B - Universitatea "Constantin Brâncuşi" din Târgu-Jiu

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B - Universitatea "Constantin Brâncuşi" din Târgu-Jiu
CONTENTS
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Ion BULAC - VIBRATIONS OF THE BICARDANIC TRANSMISSIONS WITH ELASTIC SUPPORTS……
Mădălina DUMITRIU - ON THE DYNAMIC VERTICAL WHEEL-RAIL FORCES AT LOW
FREQUENCIES................................................................................................................................................
Stefan GHIMISI - STUDY CONSIDERATIONS ON THE FRETTING PHENOMENON FOR LAMELLAR
SPRINGS...........................................................................................................................................................
Ioan HITICAS, Danila IORGA, Liviu MIHON, Emanuel RESIGA, Narcis URICANU - STUDIES
AND EXPERIMENTAL RESEARCH CONCERNING THE PERFORMANCES OF THE INTERNAL
COMBUSTION ENGINE, CONTROLLED OVER THE POWERTRAIN CONTROL MODULE....................
Ioan HITICAS, Danila IORGA, Liviu MIHON, Narcis URICANU, George PICIOREA - THE
INFLUENCE OF THE INTAKE MANIFOLD SYSTEM CONCERNING THE PERFORMANCES OF THE
INTERNAL COMBUSTION ENGINE..............................................................................................................
Dan ILINCIOIU, Ion TĂTARU, Cosmin-Mihai MIRIŢOIU - RESEARCH REGARDING THE
MODAL PARAMETERS IDENTIFICATION FOR METALLIC STRUCTURES (I).......................................
Dan ILINCIOIU, Ion TĂTARU, Cosmin-Mihai MIRIŢOIU - - RESEARCH REGARDING THE
MODAL PARAMETERS IDENTIFICATION FOR METALLIC STRUCTURES (II).......................................
Iulian POPESCU, Liliana LUCA, Sevasti Mitsi - CINEMATIC AND STRUCTURAL PROBLEMS AT A
STEPPING MECHANISM USED FOR TOYS ................................................................................................
Liliana LUCA, Iulian POPESCU - GENERATION OF AESTHETIC SURFACES THROUGH
TRAMMEL MECHANISM ..............................................................................................................................
Traian MAZILU - A STUDY ON THE WHEELSET/SLAB TRACK VERTICAL INTERACTION................
Monica BALDEA - DETERMINING THE RESPONSE IN CASE OF VIBRATIONS OF STRAIGHT BARS
WITH RANDOM EXCITATIONS…………………………………………………………………………………
Corneliu MOROIANU - THE THEORETICAL CRITERIA ON THE VAPORIZATION AND
COMBUSTION RATES OF EMULSIONS WATER IN HEAVY FUEL OIL.....................................................
Gheorghe POPESCU - DYNAMIC ANALYSIS OF A CRIMPING DEVICE WITH MULTIPLE CAMS
USING MSC ADAMS (I)…………………………………………………………………………………………….
Gheorghe POPESCU - DYNAMIC ANALYSIS OF A CRIMPING DEVICE WITH MULTIPLE CAMS
USING MSC ADAMS (II)…………………………………………………………………………………………….
Constantin D.STANESCU, Liliana CAINICEANU , Tudor BURLAN - THEORETICAL RESEARCH
ON THERMAL MODELING OF A HIGH POWER AUDIO DEVICE.........................................................
Liliana CAINICEANU , Constantin D.STANESCU, Tudor BURLAN - EXPERIMENTAL
THERMAL SIMULATION OF THE HIGH AUDIO SPEAKER.....................................................................
Michail VULKOV - A GENERALIZED INTEGRAL-GEOMETRICAL THEORY IN MINING
SUBSIDENCE (I)………………………………………………………………………………………………….
Michail VULKOV - A GENERALIZED INTEGRAL-GEOMETRICAL THEORY IN MINING
SUBSIDENCE (I)………………………………………………………………………………………………….
Ovidiu ANTONESCU, Păun ANTONESCU - CINETOSTATIC CALCULATION OF MECHANISMS
PLANETARY CYLINDRICAL...........................................................................................................................
Gheorghe AMZA, Dan DOBROTA - CONTRIBUTIONS TO THE IMPLEMENTATION OF
ENVIRONMENTAL MANAGEMENT SYSTEM WITHIN THE ECO TECHNOLOGIC ORGANIZATION
Catalin Gh. AMZA, Gheorghe AMZA, Diana POPESCU - IMAGE SEGMENTATION FOR
INDUSTRIAL QUALITY INSPECTION………………………………………………………………..…………….
Oana Roxana CHIVU, Ilie PRISACARIU, Constantin RADU - THEORETICAL AND
EXPERIMENTAL CONTRIBUTIONS REGARDING MATERIALS USED IN PRODUCTION OF ACTIVE
ELEMENTS OF ULTRASONICS MOTORS-PROPERTIES, SINGULARITY PIEZOCERAMIC
MATERIALS PIC 151, 155, 255………………………………………………………………………….………….
Fiabilitate si Durabilitate - Fiability & Durability Supplement no 1/ 2012
Editura “Academica Brâncuşi” , Târgu Jiu, ISSN 1844 – 640X
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CIOFU Florin, NIOATA Alin - PLATYNG OF WEAR RESISTANT SURFACE LAYERS BY THE
METHOD - LASER SINTERING......................................................................................................................
CIOFU Florin, STĂNCIOIU Alin - ALUMINISATION THERMOCHEMICAL TREATMENT APPLIED
TO WEAR RESISTANT COATINGS.................................................................................................................
Constanța Rădulescu, Liviu Marius Cîrțînă - STUDIES REGARDING THE CALCULATION OF
SLIDING FIT DIMENSION CHAIN ...............................................................................................................
Dan DOBROTĂ, Gheorghe AMZA - CONTRIBUTIONS TO THE DEVELOPMENT OF A MODEL OF
ECO TECHNOLOGIC ORGANIZATION........................................................................................................
Yury GUTSALENKO
FRACTURE
FEATURES
OF
METAL
BINDING
WHEN DIAMOND-SPARK GRINDING…………………………………………………………………………….
Tatyana TRETYAK, Yury GUTSALENKO, Alexander MIRONENKO - MODELING OF RUNNING
CUTTERS FOR SHAPING OF IMPROVED NONINVOLUTE TOOTH GEARS ………………………………
Cătălin IANCU - FROM ZERO-DIMENSIONAL TO 2-DIMENSIONAL CARBON NANOMATERIALS part I: TYPES OF CNs....................................................................................................................................
Cătălin IANCU - FROM ZERO-DIMENSIONAL TO 2-DIMENSIONAL CARBON NANOMATERIALS part II: GRAPHENE.................................................................................................................... ....................
Cristina Ionici - PLASTIC DEFORMATION ON SINTERED STEELS BY POWDER IRON.......................
Cristina Ionici - STUDIES ON MICROSTRUCTURE OF PREALLOYED POWDER FE STEEL............
Ilie ISARIE, BOKOR Corina, CIOFU Florin - SPARK-PLASMA SINTERING (SPS) OF VARIOUS
CONVENTIONAL AND NANOSTRUCTURED POWDERS...........................................................................
Minodora Maria PASĂRE - DETERMINATION OF ELECTRODEPOSITION HARDNESS BY
ANALYTICAL MODELING
- PART
I - Ni-P COATINGS OBTAINED BY VARYING THE
ELABORATION TIME....................................................................................................................................
Minodora Maria PASĂRE, Delia NICA BADEA - DETERMINATION OF ELECTRODEPOSITION
HARDNESS BY ANALYTICAL MODELING - PART II - Ni-P COATINGS OBTAINED BY VARYING
THE ELABORATION TIME............................................................................................................................
Valeriu PLESEA, Marius Eremia VLAICU POPA, Cristian TOMESCU - ASSESSMENT ON
QUALITY OF THE METALLIC REINFORCEMENTS USED FOR SUPPORT AND SECURITY OF THE
UNDERGROUND EXCAVATIONS.................................................................................................................
Constanţa Rădulescu - ASPECTS REGARDING THE FORMATION CHAINS SIZES
TO
SUBASSEMBLIES OF THE FIELD THE MECHANICS HEAVY......................................................
Alin STĂNCIOIU, Florin-Cristian CIOFU - RESEARCH ON INCREASING ACTIVE LIFE OF
CUTTING TOOLS...........................................................................................................................................
Alexandru STANIMIR, Catalin ROSU, Cosmin MIRITOIU, Dumitru PANDURU, Emil PATRU AN ANALYSIS OF THE MANUFACTURING PRODUCTIVITY WHEN THE SAME PIECE IS
PERFORMED ON 3 VERSUS 4 AXES MACHINING CENTERS…………………………………………….….
Gheorghe AMZA, Zoia APOSTOLESCU, Maria Dragomir GROZA, Liana Sanda PAISE CONTRIBUTIONS FROM SMOKE ON IMPACT OF WELDING PROCEDURES HEALTH OPERATORS
WELDER...........................................................................................................................................................
Gheorghe AMZA, Zoia APOSTOLESCU, Liana Sanda PAISE, Maria Dragomir GROZA IMPACT ON CONTRIBUTIONS FUMES FROM WELDING PROCEDURES WELDER HEALTH
OPERATORS ............................................................................................................................. ....................
Eugen Dumitru BUSA - FEATURES FOR TRANSPORT AND AIR MECHANICAL SYSTEMS OF
DANGEROUS GOODS....................................................................................................................................
Camelia CĂPĂŢÎNĂ, Gheorghe GĂMĂNECI - STUDIES REGARDING THE MANUFACTURE OF
RED GLASSES USED IN VEHICLE CONSTRUCTION INDUSTRY ............................................................
Camelia CĂPĂŢÎNĂ, Gheorghe GĂMĂNECI - GLASS PLATES FOR MOTOR VEHICLES AND
OTHER MEANS OF TRANSPORT..................................................................................................................
Dan Horia CHINDA - THE SOCIAL IMPLICATION OF INDUSTRIAL DESIGN…………………………..
Daniela Dorina FULOP, Tiberiu Rusu, Dan Viorel, Istvan FULOP - RISK BASED MAINTENANCE
IMPLEMENTATION OF REGENERATION BOILER AT S.C. ―SOMES DEJ‖ COMPANY........................
Ovidiu GAVRIS - METHODS FOR DETERMINING THE OPTIMAL SOLUTION FOR THE
REHABILITATION OF CEMENT CONCRETE ROAD PAVEMENTS..........................................................
Fiabilitate si Durabilitate - Fiability & Durability Supplement no 1/ 2012
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Edward GHEORGHIOSU, Attila KOVACS, Sorin BORDOŞ - FACILITES FOR ELECTRIC
DETONATORS TESTING, ON HIGH TECHNICAL LEVEL AND IN SAFETY CONDITIONS
REGARDING OF REQUIREMENTS OF EUROPEAN STANDARDS...........................................................
Cătălina IANĂŞI - MANAGEMENT OF THE ECONOMIC ENTERPRISES - THE HARD OR THE SOFT
APPROACH?...................................................................................................................................................
Attila KOVACS, Daniela-Carmen RUS , Edward- Jan GHEORGHIOSU - THE SPECIAL
CONSTRUCTION FACILITY AT INCD-INSEMEX FOR TESTING EXPLOSIVES AND CHEMICAL
FERTILIZERS WITH DETONATION IN SAFE CONDITIONS………………………………………………….
Roxana Gabriela POPA, Maria CĂLINOIU - TECHNOLOGIES FOR BIOREMEDIATION OF SOILS
CONTAMINATED WITH PETROLEUM PRODUCTS........................................................................
Mihai MAGYARI, Sorin BURIAN, Martin FRIEDMANN, Lucian MOLDOVAN - ASPECTS
REGARDING THE DESIGN AND PERFORMANCE OF FLAMEPROOF ELECTRIC MOTORS
SUPPLIED VIA STATIC FREQUENCY CONVERTERS FOR EXPLOSIVE ATMOSPHERES.....................
Monica BALDEA - RELIABILITY,COMPONENT OF INDUSTRIAL PRODUCTION QUALITY ………..
Delia NICA-BADEA, Minodora Maria PASARE - CONDITION ASSESSMENT OF SUBJECTIVE
COMFORT AND THE REACTIONS OF THE POPULATION IN THE URBAN CONTEXT OF
EXPOSURE TO NOISE....................................................................................................................................
Alin NIOAȚĂ, Florin CIOFU - PROMOTING THE MANAGEMENT BASED ON KNOWLEDGE IN
THE ROMANIAN ORGANIZATIONAL ENVIRONMENT...............................................................................
Florin Adrian PĂUN, Mihaela PĂRĂIAN, Emilian GHICIOI, Niculina VĂTAVU, Leonard LUPU,
Adrian JURCA - DEVELOPMENT OF THE TEST METHODS OF THE CONVEYOR BELTS USED IN
ENVIRONMENTS ENDANGERED BY EXPLOSION HAZARDS..................................................................
Irina Ramona PECINGINĂ - INDUSTRIAL GAS PURIFICATION USE OF BIOFILTERS.....................
Ali BEAZIT, Gheorghe SAMOILESCU - EFFICIENCY ANALYSIS OF THE LIQUID CONTROLLER
WITH A RING VALVE......................................................................................................................................
Iuliana Carmen BĂRBĂCIORU - STATISTICAL HYPOTHESIS TESTING USING FUZZY
LINGUISTIC VARIABLES................................................................................................................................
Jan-Cristian GRIGORE, Alexandru BOROIU, Andrei-Alexandru BOROIU - PROPOSALS TO
IMPROVE THE RELIABILITY MODELING IN THE CASES OF TRUNCATED TESTS...............................
Mădălina Roxana BUNECI - GROUPOIDS AND IRREVERSIBLE DISCRETE DYNAMICAL SYSTEMS
(I)……………………………………………………………………………………………………………………..….
Mădălina Roxana BUNECI - GROUPOIDS AND IRREVERSIBLE DISCRETE DYNAMICAL SYSTEMS
(II)…………………………………………………………………………………………………………………….….
Constantin Cristinel GIRDU - THE CALCULATION METHOD FOR SPHERICAL OPERATORS IN
MALKIN'S MODEL.........................................................................................................................................
Jan-Cristian GRIGORE - NUMERICAL APPLICATIONS ON RIGID SOLID CALCULATION USING
LINEAR ELASTIC METHOD.............................................................................................................
Teodora HRISTOVA, Ivan MININ - DЕTERMINATION OF THE DRUM MILLS’ ENGINE CAPACITY
BY USING NEURAL NETWORK WITH SUBORDINATE INPUT PARAMETERS……………………………
Stefan IOVAN, Gheorghe Iulian DAIAN - ENTERPRISE SERVICES ARCHITECTURE IN THE
WORLD OF INFORMATION TECHNOLOGY..............................................................................................
Marcel LITRA, Stefan IOVAN - INTERMODAL TRANSPORT AND STANDARDISATION....................
Miodrag IOVANOV - AN THE ECUATION Re [(a)f(x)]=0, fєS................................................................
Nicoleta-Maria MIHUT - IMPROVING THE PERFORMANCES OF THE CONTINUOUS TRANSPORT
INSTALLATIONS WITH BAND (I)................................................................................................................
Nicoleta-Maria MIHUT - IMPROVING THE PERFORMANCES OF THE CONTINUOUS TRANSPORT
INSTALLATIONS WITH BAND (II)................................................................................................................
Adrian Stere PARIS - STATISTICAL METHODS AND THE RELIABILITY OF PRODUCTION
EQUIPMENTS………………………………………………………………………………………………………
Adrian Stere PARIS, Gheorghe AMZA, Claudiu BABIŞ, Dan Niţoi - STATISTICAL ANALYSIS OF
SOME EXPERIMENTAL FATIGUE TESTS RESULTS...................................................................................
Vladimir Dragoş TĂTARU, Mircea Bogdan TĂTARU - A NUMERICAL METHOD USED FOR
KINEMATIC SURVEY OF A COMPLEX MECHANICAL SYSTEM WITH FOUR ROTATING RIGI..
SOLIDS............................................................................................................................. ...............................
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Vladimir Dragoş TĂTARU, Mircea Bogdan TĂTARU - A NUMERICAL METHOD USED FOR
KINEMATIC SURVEY OF A COMPLEX MECHANICAL SYSTEM WITH TWO ROTATING RIGID
SOLIDS AND TWO RIGID SOLIDS IN TRANSLATIONAL MOTION..........................................................
V.M. UNGUREANU - A NEW REPRESENTATION RESULT FOR STOCHASTIC DIFFERENTIAL
EQUATIONS WITH INFINITE MARKOV JUMPS AND MULTIPLICATIVE NOISE…………………………
Cristiana VOICAN, Constantin STANESCU - FLEXIBLE SERVICE BINDING IN DISTRIBUTED
AUTOMATION AND CONTROL SYSTEM………………………………………………………………………..
Cristiana VOICAN - SERVICE ORIENTATION IN DISTRIBUTED AUTOMATION AND CONTROL
SERVICE………………………………………………………………………………………………………………..
Fiabilitate si Durabilitate - Fiability & Durability Supplement no 1/ 2012
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VIBRATIONS OF THE BICARDANIC TRANSMISSIONS WITH
ELASTIC SUPPORTS
Ion BULAC
Doctorand, Universitatea din Pitești, email: [email protected]
Abstract: In order to study the lateral vibrations of the policardanic transmissions, they assimilate with the
elastic systems of bars articulated between them and suspended by elastic cantilivers, the bars having in their
component different sections.In this paper some bases of computation for own pulsations are elaborated and
numerical calculations are performed for this purpose.
Keywords: cardan, peak revolutions.
1. FIELD MATRIX.STATUS VECTOR
The partial differential equation of the opened transverse vibration of an average fiber bar
(see Figure 1) is [1], [6], [10] :
Fig.1.
 4 w A  2 w

0
x 4 EI t 2
(1)
where: w - is the deflection;
A- normal section area;
ρ - the density;
E - longitudinal elasticity moment;
I- is the geometrical inertial moment of a bar in regard to the normal main
central axis on the AXY plane.
A particular solution of the equation (1) is [1], [6], [10] :
w( x, t )  f ( x) cos( pt   )
(2)
where f(x) is the harmonic vibrations amplitude, and this function fulfils the conditions:
d2 f
M ( x)
d3 f
F ( x)
df



;
(3)
  (x) ;
2
3
EI
EI
dx
dx
dx
θ, M, F being the amplitudes, respectively of the section rotation, of the bending moment and
cutting force.
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Fiabilitate si Durabilitate - Fiability & Durability Supplement no 1/ 2012
Editura “Academica Brâncuşi” , Târgu Jiu, ISSN 1844 – 640X
One considers the notations:
- f A  F (0) ;  A   (0) ; M A  M (0) ; FA  F (0) ;
f B  F (l ) ;  B   (l ) ; M B  M (l ) ; FB  F (l )
for the amplitudes of the displacements from the end sections A and B;
-   ;  A  ;  B  for the status vectors, defined by the relations:
   f , , M , F T ;  A    f A , A , M A , FA T
;
(4)
 B    f B , B , M B , FB T
- f i (z) , i=1,2,3,4 for the Krâlov functions, defined by the relations:
ch( z )  cos( z )
sh( z )  sin( z )
; f 2 ( z) 
;
f1 ( z ) 
2
2
ch( z )  cos( z )
sh( z )  sin( z )
; f 4 ( z) 
f 3 ( z) 
2
2
z
z
z
e e
e  ez
where : ch( z ) 
; sh( z ) 
;
2
2
- F (z ) – for the Krâlov matrix defined by the relation :
 f1 ( z )
 f ( z)
F ( z )   4
 f 3 ( z)

 f 4 ( z)
f 2 ( z)
f1 ( z )
f 4 ( z)
f 3 ( z)
f 3 ( z)
f 2 ( z)
f1 ( z )
f 2 ( z)
(5)
(6)
f 4 ( z )
f 3 ( z ) 
f 2 ( z )

f1 ( z ) 
(7)
- α – for the parameter defined by the relation:
A
  4 p2
(8)
EI
-   ,   – for the diagonal matrix:
1
1 0
1

0 
   0 0

0 0

0
0

1
 2 EI
0




0 

1
 3 
 EI 
0
0
;  1
1 0
0 

0 0

0 0
0
0
  2 EI
0





3
  EI 
0
0
0
(9)
- R  - the field matrix defined by the relation:
where was noted with: z  x
R   1 F (x) 
With the relations [1], [6], [10] are obtained the relations between the status vectors:
   1 F (x)  A  ;  B   R A 
In the case where the bar is made out of segments with different sections (see Figure 2),
then the field matrices of the segments are given by the relations:
6
(10)
(11)
Fiabilitate si Durabilitate - Fiability & Durability Supplement no 1/ 2012
Editura “Academica Brâncuşi” , Târgu Jiu, ISSN 1844 – 640X
Fig.2.
Ri    i 1 F ( i xi ) i  , in the presented case, i=1,2,3
(12)
and between the status vectors are the relations:
 B   R1  A  ; C   R2  B  ;  D   R3 C 
from which results:
 D   R3 R2 R1  A 
(13)
(14)
and the field matrix for the entire bar is:
R  R3 R2 R1 
(15)
2. THE DISTRIBUTED MASS MODEL OF THE OF THE DOUBLE DRIVE SHAFT
TRANSMISSION
One associates the equivalent model from to the constructive model of the double drive shaft
transmission (see Figure 3.) and in the sections A and D are placed the elastic bearers that are
connected to the mounting frame, that have the elastically constants:
Fig.3.
Assimilating the bonds from A and D with the articulations, one will obtain:
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Fiabilitate si Durabilitate - Fiability & Durability Supplement no 1/ 2012
Editura “Academica Brâncuşi” , Târgu Jiu, ISSN 1844 – 640X
MA  MD  0
(16)
The cutting forces from A and D are given by the relations:
FA  k A f A ; FD  k D f D
(17)
Next are obtained the status vectors:
;  D    f D , D ,0,k D f D T
 A   FA / k A , A ,0, FA T
If one uses the notations:
1

 R11 R12 
0

kA 
R


R22 
21


1
0
TA   
 R3 R2 R1 T A 
(19)
 ; R 
 R31 R32 
0 0 




 R41 R42 
0 1 
then the status vectors from points A and D can be written under:
 A   TA  A , FA T
and the equality :
(18)
 
 D   R3 R2 R1  A 
(20)
(21)
becomes:
 fD 
 

 D   R   A 
(22)
F 
 0 
 A


 k D f D 
and from here is obtained the homogenous equation system in  A , F A , f D :
(23)
f D  R11 A R12 FA ; 0  R31 A  R32 FA ;  k D f D  R41 A  R42 FA
In order that the system (23) to have a solution different then zero is needed that the
determinant to be equal with zero.
 ( p)  0
(24)
 
where :
 R11
 ( p)   R31
 R41
R12
R32
R42
1 
0 
 k D 
(25)
3. THE REPRESENTATION OF THE SPECIFIC WAYS OF VIBRATION
In the graphical representation of a vibration mode there are calculated the amplitudes f
in different sections of the defections for the pulse p that corresponds to this mode of
vibration. So it is assigned to the deflection f A the numerical value equal with the unity and
then from the system () results:
R
R
FA  k A ;  A   32 ; f D  k A ( R12  R11 32 )
(26)
R31
R31
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The deflections from sections B and C are the first elements of the column matrices
 B  , C , that are obtained from the relations:
A 

 C   R2 R1 TA  A 

 FA  ;
 FA 
 B   R1 TA 
(27)
Fig.4.
The deflections from the intermediary points (see Figure 4.) are the first elements of the
column matrices  1  ,  2  , 3  and are calculated with the relations:
1   1 1 F (1 x1 )1 TA  A , FA T
 2    2 1 F ( 2 x2 ) 2  B 
 3    3 1 F ( 3 x3 ) 3  C 
(28)
(29)
(30)
4. NUMERICAL APPLICATION
One considers the double drive shaft transmission of an off-road vehicle for which:
k A  85  10 6 N / m ; k D  20  10 6 N / m ; l1  0,07m ; l 2  0,59m ; l3  0,25m ;
A1  19,6  10 4 m 2 ; A2  3,6 10 4 m 2 ; A3  7,06 10 4 m 2 ; 1   2   3  7800kg / m 3
For the first approximation the double drive shaft transmission is replaced with a
constant section bar, yielding seats at both ends, made out of three same length parts.
In this case the following values for the characteristic pulses are obtained:
p1  748,52s 1 ; n1crt  7151,51rot / min
p 2  2519,79s 1 ; n2crt  24074,42rot / min
considering the bar with the complete section with ext  50mm
p1  1062,53s 1 ; n1crt  10151,56rot / min
p 2  4004,91s 1 ; n2crt  38263,47rot / min
considering the bar with the circular section with ext  50mm and int  45mm
For the real double drive shaft transmission with the data presented above, one obtains these
values for the characteristic pulses:
p1  876,66s 1 ; n1crt  8375,78rot / min
p 2  2827,37s 1 ; n2crt  27013,15rot / min
Accordingly to the characteristic pulses the characteristic modes of vibration are obtained as
in Figure 3.c,d
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5. CONCLUSIONS
1. Calculating the peak revolutions with this method, even if it is more complicated and
hard, it is closest to reality. By comparing the value of the first critical calculated revolution
with the relation :
D2  d 2
[rot/min]
(31)
L2
with the value obtained with this method, for the same double drive shaft transmission, a
difference of 17% is obtained between the two values.
2. In automotive construction, the most frequent case is the one where the bearer from A is
rigid (the cardan shaft with the front axle) and the one from D is elastic (the connection of the
cardan with the engine-gearbox ensemble). Considering those two, the calculation program
elaborated on this method can determine the influence of the elastic constants on the peak
revolutions.
3. In a matter that concerns the characteristic modes of vibration, the amplitude of the medium
fiber bar calculated in the characteristic points drops as the rigidity from D increases. For an
increase in the elastically constant from 20·106 N/m to 85·106 N/m , the points D amplitude
drops four times for the first characteristic pulsation. The values of the peak revolutions
decrease as the rigidity for bearer D decreases.
4. To avoid the disturbing effects of the peak revolutions it is wanted that the first
characteristic frequency n1 to be as lowest as it can be and the second characteristic frequency
n 2 to be as highest as it can be, so that the transition to be smooth.
5. The increase of the second peak revolution can be done by using the cardan shafts with
high rigidity that are obtained by reducing the length or by increasing the exterior diameter. In
the construction of automotive is usually used the first constructive method, through which
the long bio-cardan transmissions are replaced with multi-cardan transmissions with short
shafts.
n  ncrt  1,21  10 7
REFERENCES
1. BUZDUGAN, GH. FETCU, LUCIA., RADEȘ, M., Vibrațiile sistemelor , R.S.R. Academy
Publishing House, Bucharest, 1975.
2. DUMITRU, N., NAHU, GH., VINTILĂ, DANIELA., Mecanisme și transmisii mecanice, Didactic
and Pedagogical Publishing House, Bucharest, 2008.
3. DUDIțĂ, FL., Transmisii cardanice, Technical Publishing House, Bucharest, 1966.
4. DUDIțĂ, FL., DIACONESCU, D., BOHN, CR., NEAGOE, M., SĂULESCU, R., Transmisii
cardanice,Transilvania Expres Publishing House, Brașov, 2003.
5. HARISS, C., CRUDU, GH., Șocuri și vibrații, Technical Publishing House, Bucharest, 1968.
6. PANDREA, N., PÂRLAC, S., Vibrații mecanice, University of Pitești Publishing House, Pitești,
2000.
7. PANDREA, N., PÂRLAC, S., POPA, D., Modele pentru studiul vibrațiilor automobilelor, Tiparg
Publishing House, Pitești, 2001.
8. PANDREA, N., Elemente de mecanica solidelor în coordinate plucheriene, Romanian Academy
Publishing House, Bucharest,2000.
9. RIPIANU, A., CRĂCIUN, I., Osii, arbori drepți și arbori cotiți, Technical Publishing House,
Bucharest, 1977.
10. VOINEA, R., VOICULESCU, D, SIMION, FL., Introducere în mecanica solidului cu aplicații în
inginerie, R.S.R. Academy
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Fiabilitate si Durabilitate - Fiability & Durability Supplement no 1/ 2012
Editura “Academica Brâncuşi” , Târgu Jiu, ISSN 1844 – 640X
ON THE DYNAMIC VERTICAL WHEEL-RAIL FORCES
AT LOW FREQUENCIES
Assistant Prof. PhD. stud.eng. Mădălina DUMITRIU
Department of Railway Vehicles, University Politehnica of Bucharest
313 Splaiul Independentei, sector 6, 77206, Bucharest, Romania
[email protected]
Abstract To homologate the railay vehicles, from the pespective of dynamic behavior, the dynamic forces
generated at the wheel/rail interface should be limited, in order to comply with the criterion regarding the
rolling track fatigue. The meeting of this requirement implies the vehicle adjustment in its construction. This
paper examines the influence of certain vehicle parameters upon the magnitude of the dynamic vertical loads
derived during travelling on a track with random irregularities. It will be shown how the minimizing condition
of the dynamic vertical loads can result into the best primary suspension damping.
Keywords: railway vehicle, dynamic vertical load, track irregularities
1. Introduction
The dynamic forces generated at the wheel/rail interface while the railway vehicles are
rolling will occur due to the track irregularities [1], irregularities of the rolling surfaces [2],
discontinuities of the rail contact surfaces (joints, switches, crossings) [3] or to the local
defects of the wheel contact surface (wheel flat) [4]. The range of the dynamic forces derived
at crossing over the track irregularities expands to circa 20 Hz, unlike the dynamic forces of
over 20 Hz that occur due to the wheel/rail structural vibrations [5, 6]. The dynamic forces
overlap with the static ones, which will in time result into the deterioration of the track.
While designing the railway vehicles, the dynamic forces are expected to comply with
the limits included in the standards [7, 8, 9]. In Europe, the vertical forces that stress the
rolling track are limited, due to reasons concerning the track fatigue conditions - in fact, this
is one of the homologation requirements of the railway vehicles [8]. All these limitations
imply an adjustment of the railway vehicle in its construction.
This paper examines the influence of certain vehicle parameters upon the magnitude of
the dynamic vertical loads derived during travelling on a track with random irregularities.
Here we find mentions about velocity, vehicle axle bases and wheelset mass, in correlation
with the suspension damping characteristics. It will be shown how the minimizing condition
of the dynamic vertical loads can result into the best primary suspension damping.
2. The vehicle mechanical model
The case study relates to a four-wheelset, two-level suspension railway vehicle,
travelling at a constant velocity V on a track with random longitudinal defects.
Should we disregard the coupling effects between wheels derived from the propagation
of the bending waves in the rails in the frequency range specific to the vertical vibration of the
vehicle, an equivalent model with concentrated parameters will be adopted for the track.
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Opposite each axle, the track is represented by an oscillatory system with a freedom degree
that can move vertically, where the corresponding travelling is zrj, for j = 14. The equivalent
track model has the mass mr, rigidity kzr and the damping coefficient czr.
The vehicle model includes a body with parameters distributed for the carbody and a
system of rigid bodies, namely the axles and the suspended masses of the two bogies.
The carbody of a length L is modelled by an Euler-Bernoulli beam of a constant section
and an uniformly distributed mass, with the bending model EI and mass per length unit m.
The structural damping of the carbody will be also weighed in, by the damping coefficient .
The displacement of a beam section in relation to the mobile referential Oxz attached to the
rear carbody end is w(x,t), where t is time. The positions of the carbody suspension points on
the secondary suspension are given by the distances l1 and l2.
The suspended masses of the bogies are considered to be two-degree of freedom rigid
bodies, i.e. the bounce movement zbi and pitch bi, with i = 1, 2. The mass of a bogie is mb
and its inertia moment J b  mbib2 , where ib – the gyration radius of the bogie.
The wheelset with mass mw have only one degree of freedom, which is the vertical
movement zwj, with j = 14.
The suspension levels of the vehicle, two per each bogie, are modelled via Kelvin-Voigt
systems. The primary suspension has one Kelvin-Voigt system working on the transition
motion, and the secondary suspension has two Kelvin-Voigt systems for translation and
rotation. The elastic constants are kzb, kzc and kc, and the damping ones czb, czc and cc.
Figure 1. The mechanical model of the vehicle-track system.
To calculate the dynamic vertical forces, the hypothesis of the linear hertzian contact
between wheel and rail is assumed
Q j  k H ( zwj  zrj   j ) , for j = 1 to 4,
12
(1)
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where j, with j = 14, represents the track longitudinal irregularities opposite the axle j, and
kH – the rigidity of the wheel-rail contact.
Upon taking into account the first two natural bending modes only, symmetrical and
anti-symmetrical, the vibration of the vehicle-track system is described by a set of 16 coupled
equations with ordinary derivatives.
The movement equations with partial derivatives are processed via the modal analysis
method. For this reason, the rigid and bending carbody modes are taken into consideration,
reading as

L

w( x, t )  zc (t )   x  c (t )   X k ( x)Tk (t ) ,
2

k 2
(2)
where zc(t) and c(t) represent the carbody vibration rigid modes, namely the pitch and
bounce, Tk(t) is time-dependent function and Xk(x) is the eingenfunction of the bending
vibration mode i
X k ( x)  sin k x  sinhk x 
sin k L  sinhk L
(cos k x  coshk x) ;
cos k L  coshk L
(3)
with k  2k m /( EI ) and cos k L cosh k L  1  0 , where k is the natural pulsation of the
vibration mode k.
In order to calculate the dynamic vertical forces, the track irregularities are considered as
random and stationary. The power spectral density of track irregularities need to be expressed
as a function of angular frequency  = V according to the relation
G () 
Ac2V 3
[2  (Vc ) 2 ][2  (Vr ) 2 ]
,
(4)
where  is the wave number, c  0,8246 rad/m, r  0,0206 rad/m, and A = 4,03210-7
rad m or A = 1,08010-6 rad m, depending on the track quality.
Starting from the frequency response factors of dynamic forces and the power spectral
density of track irregularities, the power spectral density of the dynamic forces can be
calculated
2
GQj ()  G() H Qj () , for j = 1 to 4.
where

(5)

HQj ()  k H H wj ()  H rj ()  H j () ,
(6)
with H wj () and H rj () the frequency responses of the wheel and rail j, and H j () the
frequency-domain track irregularity against the wheelset j.
Next, the root mean square of the dynamic vertical wheel/rail forces is determined on
basis of the above
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
Qj 
1
GQj ()d , j = 1 to 4.

(7)
0
3. The estimation of the dynamic forces at a railway vehicle
This section presents the results of numerical simulations regarding the influence of the
velocity behavior, the axle bases of the vehicle, the wheelset mass and the suspension
damping on the dynamic vertical wheel/rail forces.
The model parameters for a passenger coach are: mc = 34320 kg; EI = 3.2109 Nm2;
L = 26.4 m; 2ac = 19 m; ic = 7.6 m; 4kzc = 2.4 MN/m; 2kc = 1.6 MNm; 4czc = 68.88 kNs/m;
2cc = 2.87 kNm; mb = 3200 kg; ib = 0.8 m; 2ab = 2.56 m; 4kzb = 4.4 MN/m; 4czb = 52.21
kNs/m; mw = 1686 kg; mw = 1686 kg; mr = 180 kg; 2kzr = 170 MN/m; 2czr = 52 kNs/m;
2kH = 3000 MN/m.
To facilitate the analysis of vibrations, the damping ratio of the suspension levels is
considered uncoupled, as below
 b, c 
4cb,c
2 4kb,c mb,c
.
(8)
Figure 2 shows how velocity influences the dynamic vertical forces at the four wheelsets
of the vehicle. It can be noticed that their magnitude depends on the wheelsets position inside
the vehicle and the velocity behavior. Generally speaking, the dynamic forces increase along
with the velocity. An exception would be for the two rear wheelsets of the vehicle, where the
vertical force exhibits a series of maximum and minimum values (the speed is up to 120
km/h), due to the geometric filtering effect from the wheel bases of the vehicle. At high
velocities (over 200 km/h), a range where the magnitude of the dynamic forces is more
important, the highest values are noticed at the last wheelset (number 4). Starting from this
observation, the results for this case only will be presented below.
Figure 2. Influence of the velocity on the dynamic vertical forces:
—— Q1; ——Q2; ——Q3; ——Q4.
The following numerical simulations present the influence of certain vehicle parameters
upon the magnitude of the dynamic vertical forces. The investigations will be carried out in
correlation with the damping ratio of the primary suspension, an essential factor that has an
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impact upon the magniture of the dynamic forces. In fact, the damping ratio cannot be
increased however much, due to the limitations placed upon the wheel/rail dynamic vertical
forces [10].
The influence of the vehicle wheel bases is presented in figures 3 and 4. The change in
the bogie wheel base has contrary effects on the magnitude of dynamic forces, in dependence
with the damping ratio of primary suspension, as seen in figure 3. To examine the above, the
bogie axle base was given values between 2.3 and 3 m; for the primary suspension damping,
different damping ratio between 0.05....0.4, and the reference speed was V = 220 km/h. The
decrease or increase of the wheel base compared to the adopted reference value (2ab = 2.56
m) takes to a lowering of dynamic forces for only certain values of the damping ratio b. For
instance, by reducing the wheel base to 2.3 m, the lowering of dynamic forces is realized
whether the damping ratio of primary suspension is below 0.38, whereas the increase in the
wheel base to 2.8 m results into an higher value for the dynamic vertical forces, should b is
lower than 0.26. It can be noticed that for wheel bases smaller than circa 2.8 m, there is a
damping ratio of the primary suspension that turns into the minimizing of the dynamic
vertical loads. For 2ab > 2.8 m and higher dampings of the primary suspension, a reduction in
the dynamic vertical forces is evident.
Based on chart 4, the increase in the carbody wheelset leads to a decrease in the
wheel/rail dynamic vertical forces, irrespective of the damping ratio of the primary
suspension. Another important issued is that there is a value of b as circa 0.1, no matter the
wheelset magnitude, for which the dynamic vertical loads are minimum.
Figure 3. Influence of the bogie axle base.
Figure 4. Influence of the distance between
bogies.
Figure 5. Influence of the damping ratio of the
secondary suspension.
Figure 6. Wheelset mass influence.
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Figure 5 shows the influence of the damping ratio of the secondary suspension on the
magnitude of dynamic vertical forces. The starting hypothesis was that the vehicle was
travelling at speed V = 250 km/h. A first observation would refer to the fact that a higher
value of c means a decrease of the wheel/rail dynamic forces. Moreover, it can be noticed
that the damping ratio of primary suspension that makes the dynamic forces minimum is not
significantly influenced by the magnitude of c, as this is around the value of 0.1.
The wheel/rail dynamic vertical forces that have been calculated for a wheelset with
mass between 1400 and 2000 kg, at speed 250 km/h, are presented in figure 6. The other
vehicle parameters are the ones in the reference range. It is evident that the dynamic vertical
forces increase along with the wheelset mass. In this specific case, the best damping of
primary suspension is pointed out at, for which the dynamic vertical forces are minimum.
4. Conclusions
The magnitude of the dynamic vertical forces generated at the wheel/rail interface is an
important prerequisite in the homologation process for the railway vehicles and their
admission into the international traffic. To limit the dynamic vertical forces derived at the
wheel/rail interface, construction measures are provided, both for the rolling track and the
vehicle. Since it is difficult to achieve a track with a perfect geometry and to maintain it at its
initial designing parameters, a special attention has been paid to the very designing process of
the railway vehicle. The limitation of the dynamic forces generated at the wheel/rail interface
implies adopting a series of measures regarding the vehicle building parameters, such as the
suspended and unsuspended masses, the wheels diameter, the suspension characteristics, etc.
The paper herein has examined the influence of certain vehicle parameters, in correlation
with the impact of the damping ratio of primary suspension upon the magnitude of the
dynamic vertical forces.
The present study has shown that a decrease of the dynamic forces can derive from
increasing the damping ratio of secondary suspension, by reducing the wheelset mass or by
raising the vehicle axle base – where all these results are independent from the damping ratio
of primary suspension. Similarly, the dynamic vertical forces can be reduced by lowering the
bogie axle base, but only for a certain range of values given to the damping ratio of primary
suspension. At the same time, an important issue has been highlighted – namely, there is
value of the damping ratio of primary suspension for which the dynamic vertical forces are
minimum.
Upon the analysis of the speed behavior upon the magnitude of the vertical forces, the
conclusion is that the last vehicle wheelset will have the highest value for superior velocities.
References
[1] Sebeşan I., Mazilu T., Vibraţiile vehiculelor feroviare (Vibrations of the railway vehicles),
MatrixRom, Bucureşti, 2010.
[2] Wu T.X., Thompson D. J. Vibration analysis of railway track with multiple wheels on the rail,
Journal of Sound and Vibration, 239, 2001, 69-97.
[3] Steenbergen, M. Modelling of wheels and rail discontinuities in dynamic wheel-rail contact
analysis, Vehicle System Dynamics, vol. 44, no. 10, oct. 2006, 763-787.
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Fiabilitate si Durabilitate - Fiability & Durability Supplement no 1/ 2012
Editura “Academica Brâncuşi” , Târgu Jiu, ISSN 1844 – 640X
[4] Wu T.X., Thompson D.J., A hybrid model for the noise generation due to railway wheel flats,
Journal of Sound and Vibration 251, 2002, 115-139.
[5] Mazilu T., Vibraţii roată-şină (Wheel rail vibrations), Ed. MatrixRom, Bucureşti, 2008.
[6] Thompson D., Railway noise and Vibration: mechanisms, modelling and means of control,
Elsevier, London, 2009.
[7] Lyon D., A review dynamic vertical track forces, Research programme, Report no. IFLT/111257,
2002.
[8] UIC Leaflet 518: Testing and approval of railway vehicles from the point of view of their dynamic
behaviour. Safety,Track fatigue, Running behaviour, September 2009.
[9] GM/TT0088, Permissible track forces for railway vehicles, 1993.
[10] Zhou J., Goodall R., Ren L., Zhang H., Influences of car body vertical flexibility on ride quality
of passenger railway vehicles, Proceedings of the Institution of Mechanical Engineers, Part F:
Journal of Rail and Rapid Transit, 223, 2009, 461- 471.
17
Fiabilitate si Durabilitate - Fiability & Durability Supplement no 1/ 2012
Editura “Academica Brâncuşi” , Târgu Jiu, ISSN 1844 – 640X
STUDY CONSIDERATIONS ON THE FRETTING PHENOMENON
FOR LAMELLAR SPRINGS
Prof.univ.dr.eng.Stefan GHIMISI,
―Constantin Brancusi‖ University of Târgu Jiu,[email protected]
Abstract: Fretting regimes were first mapped by Vingsbo. In a similar way, three fretting regimes will be
considered: stick regime, slip regime and mixed regime. The mixed regime was made up of initial gross slip
followed by partial slip condition after a few hundred cycles. For the study of the fretting phenomenon in case of
elastics assemblages spring slides with multiple sheets, I used the experimental stall. On the rigid support the
elastic lamella is assembling through the agency of the superior plate and of the screws.
The elastic lamella oscillates because of the rod crank mechanism with eccentric. This mechanism is auctioned
with the electrical engine assuring the necessary conditions for producing the fretting phenomenon
Keywords: fretting, transition, variable friction coefficient.
1.Introduction
Fretting is now fully identified as a small amplitude oscillatory motion which induces
a harmonic tangential force between two surfaces in contact. It is related to three main
loadings, i.e. fretting-wear, fretting-fatigue and fretting corrosion.
The main parameters were reported to be amplitude displacement, normal load,
frequency, surface roughness and morphology, and residual stresses. More recently fretting
has been discussed using the third-body concept and using the means of the velocity
accommodation mechanisms introduced by Godet et al.
Fretting regimes were first mapped by Vingsbo[1]. In a similar way, three fretting regimes
will be considered: stick regime, slip regime and mixed regime. The mixed regime was made
up of initial gross slip followed by partial slip condition after a few hundred cycles. Obviously
the partial slip transition develops the highest stress levels which can induce fatigue crack
nucleation depending on the fatigue properties of the two contacting first bodies. Therefore
prediction of the frontier between partial slip and gross slip is required[2,3,4].
The type of surface damage that occurs in fretting contact depends on the magnitude
of the surface normal and tangential tractions. In existing fretting models the relative
displacement is assumed to be accommodated mainly microslip in the contact surface.
2. Experimental means
For the study of the fretting phenomenon in case of elastics assemblages spring slides
with multiple sheets, I used the experimental stall from fig.1.[5]
The stall permits testing for one slide and for spring slides with multiple sheets, too.
2.1. Description of the stall
On the rigid support the elastic lamella is assembling through the agency of the
superior plate and of the screws. The elastic lamella oscillates because of the rod crank
mechanism with eccentric. This mechanism is actioner with the electrical engine assuring the
necessary conditions for producing the fretting phenomenon.
The contact is charged with the assistance of 4 screws through the agency of some
helicoidally springs and through the agency of some radial-axial bearings with conic rolls.
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The helicoidally springs beforehand standard permit a charge with a normal and
known force, the presence of the radial-axial bearings assuring the eliminate of friction
between the screw and the superior plate.
Fig.1. Experimental stall
Fig.2.The system excentricity
The stall can be used for the testing at fretting of some couples by different materials.
This stall can be adapted for study of the lamellar springs with many sheets.
The lamellas used in experiments have the dimensions 560x56x2 mm and are realised by
spring steel having hardness 55 HRC.
The rod-crank mechanism permits a displace at the end (extremity) of the 20 mm
lamella and can modify this displace by changing of the system excentricity(Fig.2). The
system is actioned through the agency of electrical enging having revolution of 750 rot/min.
The experimental stand was used to study of the state of wear produced in slide
contact, specific contact leaf springs with multiple sheets by small amplitude oscillatory
motion.
In this case we have studied the phenomenon of fretting dependence of normal forces,
giving specific traces for each case. If the pressure variation in normal force of 200N we used
force and 250N duration ranging between 40000 and 60000 application of load cycles.
The wear traces resulting from attempts to push the normal force of 250N shows, just
as expected, an increase in sample size used to increase the duration of application.
Also, all traces of fretting wear tests wear identified by the presence of ―red powder‖
at the contact between the two blades.
The traces obtained for 250N and 40000 cycles are given in fig.3, for the same normal
force and 50000 and 60000 cycles for traces obtained are given in fig.4 and fig.5
Traces obtained for 200 N and 40000 cycles are given in Fig.6, for the same normal
force and 50000 and 60000 cycles for traces obtained are given in Fig.7 and 8
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Fig.3.The traces wear for a normal charcing of 250 N, Nc=40000 number of cycles
Fig.4.The traces wear for a normal charcing of 250 N, Nc=50000 number of cycles–lamella lower
Fig.5. The traces wear for a normal charcing of 250 N, Nc=60000 number of cycles–lamella upper
Fig.6. The traces wear for a normal charcing of 200 N, Nc=40000 number of cycles–lamella upper
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Fig.7. The traces wear for a normal charcing of 200 N, Nc=50000 number of cycles–lamella upper
Fig.8. The traces wear for a normal charcing of 200 N, Nc=60000 number of cycles–lamella lower
For 40000 cycles the traces obtained are distinguished by small areas of adhesion
between the two lamella, these areas increased significantly to 50000 and 60000 cycles. To
60000 cycles per slide were found in much larger areas that was present "red powder 'which
means an increase in wear with time request. For the same lifetime can be observed an
increase in area used to increase the normal force push.
The traces obtained were taken with a camera, is then processed by computer.
Examples of fretting wear are shown in Figure 9, 10.11
Fig.9 The traces wear for a normal charcing of 250 N, Nc=50000 number of cycles
3. Conclusion
The experimental stall permits realization of the experimental tries for the study of fretting.
We can determine the different size of the fretting areas and we can compare these with the
theoretical results.
Identified the presence of "red powder 'on slides and subjected to fretting wear has been an
increase in the duration of the request. For the same lifetime can be observed an increase in
area used to increase the normal force push.
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REFERENCES
[1] O.Vingsbo and M.Soderberg,On fretting maps,Wear, 126 (1988) 131-147
[2] Stefan Ghimisi, Liliana Luca, Gheorghe Popescu, Transition in the fretting
phenomenon based on the variabile coefficient of friction, International Conference on
Mechanical Engineering, Robotics and Aerospace ICMERA 2010, 2-4 december Bucharest,
Romania, Publisher Institute of Electrical and Electronics Engineers(IEEE), China, ISBN
978-1-4244-8867-4,pag.308-312
[3] Stefan Ghimisi, Study of the transition in the fretting phenomenon, Baltrib‘09, V
International Scientific Conference, Lithuanian University of Agriculture, Kaunas, Lithuania,
19-21 decembrie 2009, PROCEEDINGS, ISSN 1822-8801, pag.230-236
[4] Stefan Ghimisi, Transition in the fretting phenomenon based on the variabile coefficient
of fretting, Fiability& Durability, nr 2/2010, pag.89-92, Editura Academica Brancuşi, Târgu
Jiu, ISSN 1844ICMERA 2010, 2-4 december Bucharest, Romania, Publisher Institute of
Electrical and Electronics Engineers(IEEE), China, ISBN 978-1-4244-8867-4,pag.308-312
[5] Stefan Ghimisi, Experimental investigation of the fretting phenomenon-dependence of
number cycles, Baltrib‘09, V International Scientific Conference, Lithuanian University of
Agriculture, Kaunas, Lithuania, 19-21 decembrie 2009, PROCEEDINGS, ISSN 1822-8801,
pag.226-230,
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Editura “Academica Brâncuşi” , Târgu Jiu, ISSN 1844 – 640X
STUDIES AND EXPERIMENTAL RESEARCH CONCERNING THE
PERFORMANCES OF THE INTERNAL COMBUSTION ENGINE,
CONTROLLED OVER THE POWERTRAIN CONTROL MODULE
PhD. Eng. Ioan HITICAS, „Politehnica‖ University of Timisoara, Romania,
[email protected]
Prof. Dr. Eng. Danila IORGA, „Politehnica‖ University of Timisoara, Romania,
[email protected]
Conf. Dr. Eng. Liviu MIHON, „Politehnica‖ University of Timisoara, Romania,
[email protected]
Eng. Emanuel RESIGA, „Politehnica‖ University of Timisoara, Romania,
[email protected]
PhD. Eng. Narcis URICANU, Euromaster Tyre and Service Timisoara Romania,
[email protected]
Abstract — the paper present how can be controlled a road vehicle through a powertrain control module, a type
of ECU, programmable ECU (Electronic Control Unit), when we want to increase the performances of the
engine, compared with the standard performances of the engine. The programmable ECU is a control system
which replaces the ECU from the vehicle and is able to manage, better than the standard ECU, the behaviour of
the spark ignition engine on increasing the performances. Sports cars need to obtain the best performances from
them engine, the specific regimes at which them must function impose certain limits which will be achieved
during the competition. Nowadays the vehicles designers and engineering, working for the production cars, have
adopted many solutions from the race cars area, due to the advantage offered by these elements (lightweight
materials, fasts responses, high speeds) and system like programmable ECU. To obtain more power on the
engine, we have to find and applied the best solution concerning the internal combustion processes and the
consequences concerning the exhaust. This papers present who can be increased the performances of the spark
ignition engine through the air-flow ratio, controlled by the programmable ECU and with the sensors help, like
water temperature sensor, intake air temperature sensor, throttle position sensor, lambda sensor.
Keyword: internal combustion engine, performances, powertrain (engine) control unit, lambda, ARF.
Introduction
Today‘s road vehicles are used for many things, like arriving at time somewhere, carrying
passenger or different object, but one thing it‘s sure: we need them today more than in other
times and we count on them. For this reason, automotive designer and engineering are
working continuously to find new solutions for the needs of today's drivers. Safety and
comfort, these are two goals what must meet abundantly our cars. Close collaboration
between the fields of mechanical, electronic, materials, and others areas, have led to today's
vehicles, which offer safety and comfort, and one of these results is and the programmable
ECU. What is a programmable ECU? It‘s an electronic control unit [1] designed to increase
the performances of the engine by controlling the sensors of the vehicle, taking into account
the inputs – air and fuel, and the parameters – temperature and pressure, which are set during
the tested in real time. His target is to control the fuel injection of the spark ignition engine,
controlling and the intake air temperature, coolant temperature, heated oxygen, the injection
timing, and much more elements (fuel pomp, ignition, power, fast idle valve, sensor ground).
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Analysing these advantage offered by the programmable ECU [2], we decided to realise
the parameterization of a thermal engine with spark ignition, vehicle used for competitions at
international level. To be useful this new system applied to our engine, first we realised the
motor tuning, which involves the mechanical elements like intake manifold, exhaust
manifold, turbines, box gear and other elements, which were replaced with other with high
performances, situation which requires it. After we made the replacement of mechanical
elements, we start to analyze the wiring diagram, to make all the new connections between the
vehicle sensors and programmable ECU.
Technical Data
When we talk about thermal engine [6], [7] we have affront us more elements, but two
elements are very important: fuel and air. The fuel is an important element without the
thermal engine will not function. The first fuel used as energy power it was the diesel and the
gasoline. After the oil crises, in years ‘70, engineers started to find new energy sources and
they found the alternative fuels, biodiesel and the alcohols (used as additives for gasolines).
The new concepts applied to the production cars, namely the electric cars, which are using the
batteries, are steel too expensive for most of us. Thermal engine are steel for us a subject who
keep the attention of the automotive engineers and designer. The second element is the air,
taken from the atmosphere, necessary element for the burning process and which must be
controlled on temperature and pressure across the intake process.
We know that the spark ignition engine works on optimal conditions if the AFR (Air/Fuel
Ratio) is closer to the ideal value, which is the stoichiometric ratio, 14.7:1. This ideal situation
was made for the octane (choose this element due to his proprieties).
Lambda number is ratio between a give AFR and the stoechiometric AFR [1]:
(1)
The given AFR can be found in the following table for some of the fuel. [11]
Table1. Equivalent air/fuel ratio
Air/Fuel Ratio Equivalents
Lambda
Gasoline Propane
10.3
11.0
0.70
11.0
11.8
0.75
11.8
12.5
0.80
12.5
13.3
0.85
13.2
14.1
0.90
14.0
14.9
0.95
1.00
14.7
15.7
15.4
16.5
1.05
16.2
17.2
1.10
16.9
18.0
1.15
17.6
18.8
1.20
18.4
19.6
1.25
19.1
20.4
1.30
24
Methanol
4.5
4.9
5.2
5.5
5.8
6.1
6.5
6.8
7.1
7.4
7.8
8.1
8.4
Ethanol
6.3
6.8
7.2
7.7
8.1
8.6
9.0
9.5
9.9
10.4
10.8
11.3
11.7
Diesel
10.2
10.9
11.6
12.3
13.1
13.8
14.5
15.2
16.0
16.7
17.4
18.1
18.9
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The AFR is also a ratio between masses of the air and fuel [3]:
(2)
So, if we have a rich mixture, then we can affirm the compression ratio as 12.5: 1. This
means:
11.0:1 / 14.7:1 = 0.75
(3)
AFR / AFRstoech = λ
The oxygen sensor will manage the AFR ratio, also the λ number. This sensor is useful
concerning the volumetric efficiency. The volumetric efficiency, ηV, [3] is ―one of the most
important parameter for the evaluation of the running regime of the engine. The volumetric
efficiency is the ratio between the pressure in the cylinder/combustion chamber and the
pressure in the intake manifold.‖ [4]
The oxygen sensors have a different trigger point for stoichiometric compared to a narrow
band sensor, and the opposite ―slope‖ to the voltage curve as showed in the following figure.
It can be observed the best power area concerning the air fuel ratio. [11]
Figure1. Oxygen sensor output – narrow and wide band [11]
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Experimental research
Our studies analysed the evolution of the AFR on a spark ignition engine, with
gasoline as fuel, with target to obtain a value of the AFR, from the lambda sensor, closer to
the ideal situation, when, due to these number, we will obtain the high performances from the
engine.
The vehicle used for experimental research was a race car, involved in national and
international competition. Vehicle Renault 5, 1721 cm3displacement, 89.5 kW – maximum
power at 5400 rpm, 175 Nm – maximum torque at 3300 rpm, 8.1:1 compression ratio [12].
The connection between the powertrain control unit and the engine sensors is possible
through the OBD II plug, and a laptop which has the software used specially for this purpose
[5].
Before to add this powertrain control unit on the vehicle [8], [9], which is an ECU
tuning, we proceeded on the mechanical tuning on the engine, like replacing the exhaust pipe,
intake manifold system, the gear box, the turbine, and other elements. After this mechanical
replace, the followed element was the vehicle ECU, replaced with the new powertrain control
unit, analysing the wiring diagram to make the new connection.
The advantage of this system is the possibilities to manage the sensors of the engine
and to control them by setting the value limit, maximum and minimum values.
The below figure show us a general view of the software through we observe the
evolution of RPM (crankshaft rotate per minutes), MAP (manifold absolute pressure), TP
(throttle position), AFR (air/fuel ration), PW (pulse weight), Duty Cycle (injection timing),
CLT (coolant temperature), MAT (manifold absolute temperature). On the right side of the
windows we can manage the volumetric efficiency and the advance.
Figure2. – General view of software used for tuning
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The MAP sensor represents the absolute pressure in the intake manifold to determine the
load on the engine and the consequent fuelling requirements. The MAP sensor values must be
between 115 kPa and 250kPa and the engine will run properly.
TP is a voltage divider that gives information to the powertrain control unit about the
throttle position, from which is calculated the rate of throttle opening for acceleration
enrichment.
PW is a signal with a fixed frequency, which is turned on for part of the pulse, and is used
to control the voltage to injectors.
Duty Cycle is used to describe the amount of time that the injectors are turned on, and to
describe the ―hold‖ part of the peak and hold injector drivers.
CLT and MAT are resistors whose resistance varies with temperature.
At the end of fixing all the additional sensors, we make the first vehicle test a real time, on
the road, with constant speed, for a short distance, to eliminate the possible errors. When was
set the value of the sensor, we proceeded to the vehicle tests, and below we present only the
graph where is the AFR values.
Figure3. Evolution of AFR
As it can be seen in the figure, the AFR value varies between 11.5 and 12.5, value 12.2
archived along our measurements is a very good value. It allowed us to increase the
performances of the engine due to this ratio between air mass and fuel mass. The value of
lambda is around 0.83, which is a very good ratio at 5000 rpm. The behaviour of the engine is
very good and the fuel consumption is acceptable considering that is a rich mixture,
comparing with poor mixture, when the AFR is around 16.6.
Conclusions
As conclusions we affirm that this powertrain control unit, programmed by our team,
provided a very good behaviour of the internal combustion engine used for this purpose. We
mention that the vehicle run on the completion race after these adjustments and won. The
performances of the engine was increased, air fuel ratio, with his value 12.2, being our
witnessing. Because on the race the vehicle must run at different regimes, we realised the best
adjustments for this purpose.
As future research we will try to achieve better values of the AFR, like 13.5 to be inside
the ―best power‖ area. Also, we intend to use the powertrain control unit and for vehicle
running with alternative fuels, like propane or ethanol, or other alternative solution, which
offers a very good alternative to fossil fuels, taking into account the greenhouse effect, due to
the high level of CO2 concentration [10] on the atmosphere.
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Acknowledgment
This work was partially supported by the strategic grant POSDRU/88/1.5/S/50783, Project
ID 50783 (2009) co-financed by the European Social Fund – Investing in People, within the
sectarial Operational Programme Human Resources Development 2007-2013.
This work was partially supported by the strategic grant POSDRU/21/1.5/G/13798, inside
POSDRU Romania 2007-2013, co-financed by the European Social Fund – Investing in
People
References
B. Bowling and A. Grippo, Building a Fuel-Injection ECU, Circuit Cellar Ink 138, USA,
January 2002.
S. Ratanaprutthakul and S. Grobosch, Model checking and verification method of engine
control unit, IEEE Software Engineering (MySEC), Malaysia 2011.
De Lorenzo, Test bench for internal combustion engines, Italy, pp. 13, 2009.
Ioan Hiticas and all, Parameters control of a spark ignition engine through programmable
ECU for specific regimes, in paper, IEEE Conference, SACI 2012, Timisoara, Romania.
N.N. Hassan and all, Micro-Controller Based on-board diagnostic (OBD) system for nonOBD vehicles, IEEE Computer Modeling and Simulation (UKSim), Cambridge, April
2011.
Richard D.Atkins, An Introduction to Engine Testing and Development, SAE International,
2009.
Gordon P.Blair, Design and Simulation of Four-Stroke Engines, SAE International, USA,
1999.
Aurel P. Stoicescu, Proiectarea performanţelor de tracţiune şi de consum ale automobilelor,
Editura Tehnică, Bucureşti, 2007.
Sorin Ratiu, Liviu Mihon, Motoare cu ardere internă pentru autovehicule rutiere –procese
şi caracteristici, Editura Mirton, Timişoara, 2008.
Gervin J.C, McClain C.R, Hall F.G, Caruso P.S, A comprehensive plan for studying the
carbon cycle from space, Aerospace Conference 2003, Proceedings 2003 IEEE, vol.1, pp.
1 - 172.
www.ms3efi.com
www.renault5gtturbo.com
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THE INFLUENCE OF THE INTAKE MANIFOLD SYSTEM
CONCERNING THE PERFORMANCES OF THE INTERNAL
COMBUSTION ENGINE
PhD. Eng. Ioan HITICAS, „Politehnica‖ University of Timisoara, Romania,
[email protected]
Prof. Dr. Eng. Danila IORGA, „Politehnica‖ University of Timisoara, Romania,
[email protected]
Conf. Dr. Eng. Liviu MIHON,„Politehnica‖ University of Timisoara, Romania,
[email protected]
PhD. Eng. Narcis URICANU, Euromaster Tyre and Service Timisoara Romania,
[email protected]
PhD. Eng.George PICIOREA, „Politehnica‖ University of Timisoara, Romania
Abstract —Comfort and safety, this are two targets for today designer and engineering of the road vehicle.
Increasing the performances of the engine through all the system of the thermal engine, have concerned the main
vehicles companies to develop all the systems of the engine. One of this system is and the air intake system. This
paper presents parts of the mathematic calculation and the experimental tests of the intake manifold system
concerning the performances of the engine. The vehicle used was a BMW vehicle. We study the air flow inside
the filter housing with CFD (Computational Fluid Dynamics) simulation, being mentioned the high importance
of this system on increasing the performances of the engine.
Keyword : intake manifold, internal combustion engine, performances, simulation CFD.
Introduction
The emissions of CO2, as a consequence for burning the fossil fuels inside the thermal
engine are made the automotive designer and engineers to reanalyze all the systems of the
engine with internal combustion, because the level of the CO2 concentration in the
atmosphere presents a very high level. Another reason for which they started to reanalyze was
to increase the performances of the engine after the request of the drivers. One of this system,
which was reanalyzed was and the intake manifold system.
This paper preset the theoretical studies [1], and experimental research concerning the role
of this system in formation and distribution of the mixture air fuel inside the combustion
chamber, with consequence in power and torque of the engine.
As we know, the thermal engine can function properly only with air and fuel, in specific
conditions, as pressure and temperature. The mixture between these elements is held in the
intake manifold system. The air is taken from the atmosphere, where are also other elements,
which compose the earth atmosphere [3] like N2 – 78.1%, O2 – 20.9%, Ar – 0.9%, CO2 –
0.035% and others elements – 0.065%, with consequences on the nature of the exhaust gases.
The fuel we buy it from the station, and here are also discussions about the component of the
gasoline. On the market we can found different gasoline, but the components of the gasoline
are: sulphur (0.08 – 0.5%), aromatic hydrocarbons (42%) and benzene (3%), also with
consequences concerning the nature of the exhaust.
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Intake manifold systems have a wide variety of tasks [4], including and:
- Uniform air distribution to the cylinder
- Filtration of the air before admission into the cylinder.
- Improved performance.
- Integration air flow meter in the intake route.
- Reducing noise made by the air intake in to the engine as well as its movement inside
the intake manifold.
More, the intake manifold system has and other important task: increasing the
performances of the engine thought the supercharging effect. This is a solution to reduce the
fuel consumption and also de exhaust, by controlling the movement of the air with valves
installed for this purpose.
Technical Data
Thermal engines, (or internal combustion engine), transform the heat obtained from the
combustion chamber, into the mechanical work [5], [6], due to the proprieties of the fuels as a
consequences of chemical reactions. But not only the fuels are important in this phenomenon
but also the air. This mixture, called fresh fluid, must be introduced into the engine whit help
of the intake manifold system, which allowed to the air to reach at perfect condition for
burning process.
Figure 1 – Constructive scheme of filter system
To work properly, the engine must have a certain quantities of air, and this mass can be
calculated with the equation:
(1)
were,
Ar – Air requirements
D – Displacement [mc]
S – Speed [rpm]
Ef – The filling efficiency
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The air, before to be introduced into the engine, has the ambient pressure and the ambient
temperature. For this reason we need the intake manifold system. We know that the pressure
in the cylinder at the end of intake is influenced by hydrodynamic losses on the route.
Generally, the route of intake of an internal combustion engine with fuel injection, is
composed by air filter housing related, duct mounted between the filter and throttle body,
collector and the intake manifold, at the end of which is the intake valve with the purpose of
opening and closing the orifice passage between the gallery practiced in cylinder head and the
cylinder.
The main hydraulic resistance on the route is: air filter, throttle and valve or intake
valves. In the following figure can be seen the scheme of the route of the intake.
Figure 2.The route of intake of a spark ignition engine with direct injection [9]
Losses on the route of intake depend on fluid density and functional factors such as
engine speed, which directly influence the flow velocity. It can be define two fluid flows, as
relationships:
(2)
(3)
were,
– fresh fluid flow for ideal condition [kg/s]
ρff0 – fresh fluid density for ideal condition [kg/m3]
Vs – displacement
i – number of cylinder
n – speed [rad/s]
Tc – length of a cycle
The equation without 0 indexes means the condition for real situation when we have
losses on the route intake. The relative level of losses during the intake process is given by the
ratio of fresh fluid flow in real and ideal flow conditions without losses or other influences.
This ratio is noted with ηv and is called the degree of filling, defined bellowed:
(4)
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The degree of filling is a perfection criterion for admission process and as the ηv have a
higher value, as much the losses are small. This is a criterion for comparison of the intake
engine systems. Relation 5 shows the dependence of effective power to the degree of filling:
(5)
Were,
Pe – effective power [W]
ηe – effective yield
Qi – lower calorific power of fuel [J/kg].
λ – excess air coefficient
Lmin – minimum air necessary for combustion [kgair/kgfuel]
Maximum engine power is obtained at the highest value of the product (n∙ηv)max, due to
decrease of the degree of filling value with speed increasing, after reach its peak (Figure 3).
Figure3. Variation of the degree of filling and actual power, with speed
Effective torque Me is not depend directly by speed, but also by the degree of filling:
(6)
Experimental Research
The experimental test was realised inside of Mahle Componente de Motor Timisoara, in
testing laboratory. For testing we take the model of the intake manifold from the thermal
engine BMW N52, with dates: year of manufacturing – 2004, fuel – gasoline, cylinder
capacity – 2996 cm3, mass – 1580 kg, number of cylinder – 6 (in line), power – 189.2 kW at
6600 rpm, torque – 300 Nm at 2500 – 4000 rpm, CO2 emission – 226 g/km, compression
ration – 10.7:1.
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Our purpose is to optimise the intake manifold using the CFD simulation and, if is
possible, to increase the performances of the engine, on power and torque [7]. The CFD
simulation was made on an inhomogeneous fluid. We have the actual curve of the torque of
the engine with the ordinary intake manifold, then we realised the optimisation, we realised
the intake manifold with optimisation on the test bench, and all this curves compared with the
ideal power and torque curves.
First step in our experiment research it was to create a model using the CFD simulation
software. The model is presented in below:
Figure 4 – Intake manifold BMW N52 6 SL.
Figure 5 – Optimization of the intake manifold and
simulation of pressure drop before and after changes.
We start to create a succession of 3D simulation models to optimize the air flow inside the
inlet collector to analyze each modification [8]. For reducing the pressure inside the intake
manifold, it can be followed the Figures 5 were we modified the connection between the
distributor and a resonator tube. CFD simulation, over the intake manifold, allows us to
analyze all the difficult areas, like optimization from Figure 5, where it can be seen the
reduction of pressure inside the intake manifold.
Below are presented the scheme of the test bench from the testing laboratory from
Mahle Timisoara, where we realized the experimental research.
Figure 6 – Functional scheme of the bench test [8]
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CFD simulation started by calculation the dispersion D, between individual intake routes,
using the equation:
(7)
were,
M – Maximum pressure drop
m – Minimum pressure drop
p – Average pressure drop
And the pressure drop, PL, is calculated with the following equation:
(8)
were,
Po – outlet pressure
Pi – inlet pressure
Conclusions
The intake manifold system is a very important system concerning the performances of
the engine, by his aim. He must help the air to get into the combustion chamber, and also the
mixture consist by fuel and air. If the hydraulic resistance are not eliminated through
simulation process, of the degree of filling is not properly calculated, or if the required
quantities of air are not very well calculated, the performances of the internal combustion
engine won‘t be on the top.
After our simulation with CFD software, and after the optimization of the intake manifold,
we made the correction concerning the pressure drop. We realized the 3D model then
proceeded to realize the real model for vehicle BMW, testing the advantage of the
modification trough the simulation. The final conclusion is: we succeeded to optimize the
intake manifold of the BMW N52 vehicle, E63 engine, using CFD simulation taking into
account the degree of filling, hydraulic resistance, pressure drop and temperature.
As future research concerning the intake manifold is the phenomena of wave, which can
add a fresh flow air into the cylinder.
Acknowledgment
This work was partially supported by the strategic grant POSDRU/88/1.5/S/50783, Project
ID 50783 (2009) co-financed by the European Social Fund – Investing in People, within the
sectarial Operational Programme Human Resources Development 2007-2013.
This work was partially supported by the strategic grant POSDRU/21/1.5/G/13798, inside
POSDRU Romania 2007-2013, co-financed by the European Social Fund – Investing in
People
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References
Richard D.Atkins, An Introduction to Engine Testing and Development, SAE International,
2009.
Gervin J.C, McClain C.R, Hall F.G, Caruso P.S, A comprehensive plan for studying the
carbon cycle from space, Aerospace Conference 2003, Proceedings 2003 IEEE, vol.1, pp.
1 - 172.
Algieri A., Bova S., Influence of valve-wall distance on the intake flow in high performance,
I.C.E., SAE International, 2004.
Aurel P. Stoicescu, Proiectarea performanţelor de tracţiune şi de consum ale automobilelor,
Editura Tehnică, Bucureşti, 2007.
Sorin Ratiu, Liviu Mihon, Motoare cu ardere internă pentru autovehicule rutiere –procese
şi caracteristici, Editura Mirton, Timişoara, 2008.
Gordon P.Blair, Design and Simulation of Four-Stroke Engines, SAE International, USA,
1999.
Radu Hentiu, Studii si cercetari privind influenta sistemului de admisie asupra
performantelor motoarelor cu aprindere prin scanteie si injective indirect de combustibil,
Editura Politehnica, Timisoara, 2011.
www.mechanicvirtual.org.
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Editura “Academica Brâncuşi” , Târgu Jiu, ISSN 1844 – 640X
RESEARCH REGARDING THE MODAL PARAMETERS
IDENTIFICATION FOR METALLIC STRUCTURES (I)
1
Prof. phd. eng. Dan ILINCIOIU, University of Craiova, Faculty of Mechanics, Department
of Applied Mechanics and Civil Constructions, Calea Bucuresti Street, no. 107, Craiova,Code
200512, Romania, [email protected]
2
Eng. Ion TĂTARU, University of Craiova, Faculty of Mechanics, Department of Applied
Mechanics and Civil Constructions, Calea Bucuresti Street, no. 107, Craiova,Code 200512
3
Eng. Cosmin-Mihai MIRIŢOIU, University of Craiova, Faculty of Mechanics, Department
of Vehicles, Transports and Industrial Engineering, Calea Bucuresti Street, no. 107,
Craiova,Code 200512, Romania, [email protected]
Abstract. In this paper, starting from previous methods written by other authors, we present the theoretical
background of the modal identification for hyperstatic metallic structures (in an own way). We present also the
known methods which are used nowadays for modal parameters identification.
Keywords: excitation, eigenmodes, eigenfrequency, admittance, modal parameters
Contents:
1.
2.
3.
4.
Introduction
Theoretical background for the experimental modal analysis
Modal parameters identification steps
Conclusions
1. Introduction
The modal identification of three dimensional metallic structures consists in an
assembly of theoretical and experimental procedures for determination of those parameters
that characterize the system eigenmodes. The testing techniques for nowadays, for modal
parameters identification can be broadly classified in two majour groups (according to Manea
(2006)[17], Manea et al. (2007)[18], Miritoiu et al. (2011)[19] or Edwins (1987)[8]): the
multipoint-excitation that involves the usage of multiple shakers located at various points on
the structure and having controlled force amplitudes and phase relationships in order to nullify
the damping forces presented in the structure and to drive the structure in an undamped mode;
the single point excitation method used even if the structure is complicated and consists in
applying a force in a given point and recording the vibratory response in all interest points,
including the excitation point. The advantages of the first method are: the undamped normal
frequencies and the corresponding mode shapes are immediately produced. The major
disadvantage of the first method is: high complexity and expense in time and cost of installing
multiple shakers. The main advantage of the second method is that it requires a minimum of
equipment, but, as a disadvantage, it needs a laborious analysis to perform extensive
processing of the result to interprete the dynamic behaviour of the structure under test. It also
gives a good procedure and criteria to validate the mathematical model obtained by finite
element analysis using specialised softwares. This article presents a theoretical background of
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single point excitation method from the authors point of view, a software for modal
identification and an application for modal identification on a hyperstatic metallic structure.
Many papers present methods for eigenmodes calculus. For example, in Gomes et al.
(2008)[10] the limit spectral problems are derived for the problem on oscillations of a solid
with light inclusions. It is established that, for heavy inclusions, the limit problems are united
into a more complex resultant problem describing the far action in the set of inclusions. In
Mishakin and Samsonov (2011)[20] it is presented a method for calculating the dispersion
characteristics of eigenmodes of metal waveguides with helical corrugations on the inner
surface, which is based on the transition to a new nonortogonal system of coordinates. The
analyzed problem is reduced to solving a generalized algebraic problem. Kairov (2001)[12]
studies the effect of holes on the eigenmodes of reinforced shells of rotation. A solution is
built on the basis of the linear theory of thin elastic shells using the Ritz method. The obtained
numerical results are compared with experimental data. Tommaseo et al. study the
subharmonic excitation of the eigenmodes of charged particles in a penning trap. Komarov
(2011)[14] studies the eigenvalues and eigenfields of regular polygonal waveguides. The
lowest and high-order TE- and TM-modes are identified on a basis of united classification
scheme. Closed-form expressions for calculation of cutoff wavelengths of the lowest TE- and
TM-modes are presented. Belousov et al. (2000)[2] study methods of spectrum calculation
and parameter control of open-cavity eigenmodes. The potential of the proposed software and
hardware is demonstrated on the basis of an orotron cavity model designed and examined for
millimeter wavelengths. The numerical and experimental results are in good agreement. The
developed methods and software can be used for designing open cavities in various frequency
ranges. Vlasov (2006)[27] has determined the characteristics (eigenfrequencies and radiation
Q-factors) of elastic oscillations existing at the boundary of a cylindrical cavity in a solid
body. These oscillations become Rayleigh waves with increasing cavity radius. It was shown
that such oscillations in bodies with moderate Poisson‘s ratios (about 0.2–0.3) can exist in the
case of sufficiently large cavity diameters exceeding 100 Rayleigh wave lengths. In SchidtHattenberger (1992)[22] an important subclass of solutions has been analytically investigated
for a non-linear three coupler fiber. These were the stationary solutions or nonlinear
eigenmodes. Their stability is checked by using an exact method and numerical tests. In
Stanescu et al. (2009)[23] it was made a study for modal identification for two bars from
composite materials (bar 1 made of phenolic fireproof resin reinforced with fiberglass; bar 2
made of ortophtalic polyesteric resin reinforced with fiberglass).
Many other vibration studies exist in the engineering literature. For example, in Hu
(2011)[7] the vibration mode of the constrained damping cantilever is built up according to
the mode superposition of the elastic cantilever beam. The control equation of the constrained
damping cantilever beam is then derived using Lagrange‘s equation. There is made a
comparison between analytical and experimental methods. Xinong and Zinghui (1998)[31]
studied the active and passive control of vibration of the thin plate with Local Active
Constrained Damping Layer. The governing equations of system were formulated based on
the constitutive equations of elastic, viscoelastic, piezoelectric materials. Cao et al. (2011)[3]
studied the free vibration characteristics of circular cylindrical shell with passive constrained
layer damping (PCLD). Wave propagation approach rather than finite element method,
transfer matrix method, and Rayleigh-Ritz method was used to solve the problem of vibration
of PCLD circular cylindrical shell under a simply supported boundary condition at two ends.
Numerical results show that the presented method was more effective in comparison with
other methods. Xia and Lukasiewicz (1995)[29] studied the nonlinear, forced, damped
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vibrations of simply-supported rectangular sandwhich plates with a viscoelastic core.
Damping was taken into account by modelling the viscoelastic core as a Voigt-Kelvin solid. It
was also studied the influence of the thickness of the layers and the material properties on the
nonlinear response of the plates. Lee and Han (2006)[11] studied the free and forced vibration
of laminated composite plates and shells using a 9-node strain shell element. The natural
frequencies of isotropic and composite laminates were presented. The forced vibration
analysis of laminated composite plates and shells subjected to arbitrary loading was
investigated. Karnopp et al. (1970)[13] studied the problem of determining the natural
frequencies and modes of a statically indeterminant Timoshenko beam. By lumping the beam
properties of linear and rotary inertia at discrete points along the length of the beam and by
employing the complementary, variational principle, an approximate solution was obtained by
using simple matrix iteration.
2. Theoretical background for the modal parameters identification
Any system can be modeled by n concentrated mass points jointed by elastic elements
having kk rigidity and elements having ck damping. If this damped system, having n degrees of
freedom, is loaded by an external excitation system marked with {Q(t)}, the motion equations
are given in relation (1).
M    xt   C    xt   k   xt   Qt 
..

.


(1)

where [M], [C] and [K] represent the matrices of mass, damping and rigidity; {x(t)}
with the first and second derivatives are the vectors of displacements, velocity and
acceleration; {Q(t)} is the generalised forces vector.
The system response at external excitation is calculated with (2), where it is processed
as a sum of ‗n‘ modal contributions due to each separate degree of freedom.


k
k T
N 
X         Q  
k 1  a k    k  i   v k 



  
T

 __k   __k 
      Q 

   

__
a k    k  i   v k  


 
(2)

k
where {X(ω)} is the Fourier transform of displacement;  k and  represent the k
order eigenvector and its complex conjugate; μk is the k order of damping ratio; νk is the k
order of damped natural frequency; ak and ak are the norm constants of eigenvector; ω is the
external excitation frequency.
In practical applications in mechanical engineering, we usually replace the modal
vectors with two constants that are determined with (3).
 k
 ik  kj
k
U ij  iVij 
ak


 ik  kj
 k
k
U ij  iVij 
ak

38
(3)
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The system admittance, defined as the ratio between the displacement response and
the force excitation is calculated with (4).

n
 ij     
k 1
U ijk  iVijk
   k  i  v k 



  k  i  v k  
U ijk  iVijk
(4)
The concept of discrete system with concentrated mass in n material points was used
in the approximations adopted during the mathematical model. In order to obtain an accurate
approximation of the real system by the discrete one, n must converge to infinity. Because of
experimental and processing technique and of the necessary time for data processing, this is
impossible. The frequencies domain is limited to a reasonable width in practical applications,
which is obtained by the major resonances of the analyzed equipment and the frequency
domain of the application goal. In these conditions, the sum from relation (4) is reduced to
several components marked in the following with n. The contribution of superior and inferior
modes are included in two corrections factors known as residual flexibility S‘ij (for superior
modes) and inferior modal addmitance (-1)/(M‘ij · ω2) (for inferior modes). The system
admittance will be calculated with (5).
 ij   
1

'
M ij   2
 U ijk  iVijk

U ijk  iVijk


  S ij'







i


v



i


v
k
k
k
k 
k 1 


n

(5)
where i is the excitation point and j is the measuring point.
The modal identification of a system with n degrees of freedom assumes
determination of 4n modal parameters: μk, νk, U‘ij, V‘ij. These are the intrinsic characteristics
of the system, independent of the external conditions. The system response to different
excitations (like: seismic motion applied to base, concentrated electrodynamics forces due to
the switching phenomena, distributed forces due to wind actions and so on) can be calculated
with relation (2). The modal parameters are determined from experimental tests performed on
the system brought into a controlled vibrations state with simultaneous measurement of the
applied excitation and structure response. The controlled vibration state can be made using the
following low-level excitation methods (according to Manea (2007)[18] or Miritoiu
(2011)[19]): the relaxed step force, the one-point sinusoidal or large band steady-state
vibration excitation and the impact force. In this paper, in order to bring the metallic structure
into a controlled vibrations state, there will be used the impact force.
3. Modal parameters identification steps
To determine de modal parameters, we follow the next steps:
 We determine the frequency response characteristics by calculating the admittance
αij(ω) for all the pairs excitation/vibratory response points
 Preliminary resonances localization in the initial approximation of μ k and νk
(k=1,2,..,n) modal parameters
 The first stage identification of modal parameters μk, νk, Ukij, Vkij, S‘ij and (-1/M‘ij)
(where k=1,2,..,n) on limited frequency domains. The identification is made by using linear
procedures, determining those parameters which inserted in relation (5) generate theoretical
characteristics that approximate with minimal error the experimental calculated frequency
response function.
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 The final identification of modal parameters μk, νk, Ukij, Vkij, S‘ij and (-1/M‘ij) (where
k=1,2,..,n) on the entire frequency domain. The identification is made similar with the above
step.
4. Conclusions
In this paper we have presented the theoretical background for the modal parameters
identification. The modal parameters can be used for structural changes analysis and for
assesment of structure response to given excitations concentrated in distinct points or
distributed on the structure.
Applied on a new equipment in the prototype stage, modal identification gives
informations about the corectitude of design conception, construction, and it may give
informations concerning the improvement of the vibration response of the equipment.
This method can be used in parallel with a finite element software. A very good finite
element software can be a certain error source if it is used by an analyst that mindless of the
fact that the material characteristics are only approximate known, even if the geometrical
model is very good.
Applied on a recent mounted equipment, or on a working equipment, the modal
identification gives informations concerning the quality of the mounting process, the
weariness of material, possible cracks or the whickness of some parts.
5. Acknowledgement
This work was partially supported by the strategic grant POSDRU/88/1.5/S/50783
(2009), co-financed by the European Social Fund – Investing in People, within the Sectoral
Operational Programme Human Resources Development 2007-2013.
References
1. Adam, C., (2001) Eigenstrain induced vibration of composite plates, Acta Mechanica 148,
35-53
2. Belousov, V., I., et al., (2000) Methods of calculation and parameter control of the
eigenmodes of a simple two-mirror cavity, Radiophysics and Quantum electronics, 43(8),
663-670
3. Cao, X.,et al., (2011) Free vibration of cylindrical shell with constrained layer damping,
Appl. Math. Mech.-Engl. Ed., 32(4), 495-506, DOI: 10.1007/s10483-011-1433-7
4. Chapman, C., L., et al., (2002) Spatial eigenmodes and synchronous oscillation: Coincidence detection in simulated cerebral cortex, J. Math. Biol. 45, 57-78
5. Esmailzadeh, E., Jalali, M., A., (1999) Nonlinear oscilations of viscoelastic rectangular
plates, Nonlinear Dynamics, 18:311-319
6. Hu, M-y, Wang, A-w., (2009) Free vibration and transverse stresses of viscoelastic
laminated plates, Appl. Math. Mech.-Engl. Ed., 30(1), 101-108, DOI: 10.1007/s10483-0090111-y
7. Hu, M-y, et al., (2011) Approximate analytical soluctions and experimental analysis for
transient response of constrained damping cantilever beam, Appl. Math. Mech.-Engl. Ed.,
31(11), 1359-1370
8. Edwins, D., J., (1987) Modal testing, Bruel&Kjaer
9. Jianxin, G., Yapeng, S., (1999) Vibration and damping analysis of a composite plate with
active and passive damping layer, Appl. Math. Mech.-Engl. Ed., 20(10) 10-1075-12
10. Gomez., D., et al., (2008) Fromal asymptotics of eigenmodes of oscillation spatial bodies
with concentrated masses, Journal of Mathematical Sciences, 148(5), 650-674
40
Fiabilitate si Durabilitate - Fiability & Durability Supplement no 1/ 2012
Editura “Academica Brâncuşi” , Târgu Jiu, ISSN 1844 – 640X
11. Lee, W-H., Han S-C.,(2006) Free and forced vibration analysis of laminated composite
plates and shells using a 9-node Assumed strain shell element, Comput Mech, 39:41-58, DOI:
10.1007/s00466-005-0007-8
12. Kairov, A., S.,(2001) Effect of holes on the eigenmodes of reinforces shells of rotation,
Journal of Mathematical Sciences, 103(3), 393-397
13. Karnopp, B., H., et. al.,(1970) On the Oscillations of Statically Indeterminate Beams, Acta
Mechanica 9, 121-129
14. Komarov, V., V.,(2011) Eigenmodes of regular polygonal waveguides, J. Infrared. Milli.
Terahz. Waves., 32:40-46, DOI 10.1007/s10762-010-9755-4
15. Kulkarni, S., D., Kapuria, S., (2008) Free vibration analysis of composites and sandwhich
plates using an improved discrete Kirchoff quadrilateral element based in third-order zig-zag
theory, Comput. Mech., 42:803-824, DOI 10.1007/s00466-008-0285-z
16. Maheri, M., R., et al.,(2008) Vibration damping in sandwhich panels, J Mater Sci, 43:
6604-6618, DOI 10.1007/s10853-008-2694-y
17. Manea, I.,(2006) Experimental Modal Analysis, Universitaria Publishing, Craiova
18. Manea, I., et al., (2007) Software for mechanical systems modal identification, Annals of
the University of Craiova, Mechanical Series, 1:191-198
19. Miritoiu, et al., (2011) A comparison
between the modal parameters obtained by two
different accelerometers, The 5TH International Conference on Manufacturing Science and
Education – MSE 2011,1:39-43,Sibiu, Romania
20. Mishakin, S., V., Samsonov, S., V., (2011) Method for calculation of helical-waveguide
eigenmodes of the basis of solving the equivalent two-dimensional problem by field
expansion in circular wave-guides modes, Radiophysics and Quantum Electronics, 54(3),
174-184
21. Park, J-T., Choi, N-S., (2004) Flexural vibration analysis of a sandwhich beam specimen
with a partially inserted viscoelastic layer, KSME International Journal, 18(3), 247-356
22. Schimidt-Hattenberger, C., et al., (1992) Nonlinear eigenmodes of a three-core fiber
coupler, Optical and Quantum Electronics, 24:691-701
23. Stanescu, M., M., et al., (2009) Experimental researches concerning the properties of
composite materials with random distribution of reinforcement, Materiale Plastice, 46(2), 7378
24. Sudahar, R., M., Kant, T., (2007) On the angle ply higher order beam vibrations, Comput
Mech, 40:25-33, DOI 10.1007/s00466-006-0079-0
25. Tommaseo, G., et al., (2004) Subharmonic excitation of the eigenmodes of charged
particles in a Penning trap, Eur. Phys. J. D., 28: 39-48, DOI 10.1140/epjd/e2003-00296-0
26. Trompette, P., Fatemi, J.,(1997) Damping of beams, Optimal distribution of cuts in the
viscoelastic constrained layer, Structural Optimization, 13: 167-171
27. Vlasov, S., N.,(2006) Eigenmodes of a cylindrical cavity in a solid body, Radiophysics
and Quantum Electronics, 49(12), 956-960
28. Wang, J., M., Guo, B., Z., (2008) Analyticity and dynamic behaviour of a damped three
layer sandwhich beam, J Optim Theory Appl, 137:675-689, DOI 10.1007/s10957-007-9341-7
29. Xia., Z., Lukasiewicz, S., (1995) Nonlinear damped vibrations of simply-supported
rectangular sandwich plates, Nonlinear Dynamics, 8: 417-433
30. Xiang, Y., et al.,(2008) New matrix method for analyzing vibration and damping effect of
sandwhich circular cylindrical shell with viscoelastic core, Appl. Math. Mech.-Engl. Ed.,
29(12), 1587-1600, DOI: 10.1007/s10483-008-1207-x
31. Xinong, Z., Jinghui, Z., (1998) The hybrid control of vibration of thin plate with active
constrained damping layer, Applied Mathematics and Mechanics, English Edition, 19(12),
1119-1134
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Editura “Academica Brâncuşi” , Târgu Jiu, ISSN 1844 – 640X
RESEARCH REGARDING THE MODAL PARAMETERS
IDENTIFICATION FOR METALLIC STRUCTURES (II)
1
Prof. phd. eng. Dan ILINCIOIU, University of Craiova, Faculty of Mechanics, Department
of Applied Mechanics and Civil Constructions, Calea Bucuresti Street, no. 107, Craiova,Code
200512, Romania, [email protected]
2
Eng. Ion TĂTARU, University of Craiova, Faculty of Mechanics, Department of Applied
Mechanics and Civil Constructions, Calea Bucuresti Street, no. 107, Craiova,Code 200512
3
Eng. Cosmin-Mihai MIRIŢOIU, University of Craiova, Faculty of Mechanics, Department
of Vehicles, Transports and Industrial Engineering, Calea Bucuresti Street, no. 107,
Craiova,Code 200512, Romania, [email protected]
Abstract. Starting from the theoretical background written in [1], we present the package programs software
realized by the authors for modal parameters identification of this kind of structures. We also present the
experimental montage used to identify the modal parameters. In the end of the paper it is presented an
experiment for modal parameters assessment for a metallic structure statically indeterminate.
Keywords: eigenmodes, eigenfrequency, modal parameters, eigenvectors, software programs
Contents:
5.
6.
7.
8.
Introduction
Experimental Montage
Modal identification
Conclusions
1. Introduction
Starting from the theoretical background written in Ilincioiu et al.,(2012) [1], we
present the package programs software realized by the authors for modal parameters
identification of this kind of structures. We also present the experimental montage used to
identify the modal parameters. In the end of the paper it is presented an experiment for modal
parameters assessment for a metallic structure statically indeterminate.
.
2. Experimental montage
We have divided the structure in several points in order to measure the modal parameters in
different places on the structure like in fig. 1. The experimental montage is presented in fig. 2.
Fig. 1. The studied metallic structure
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Fig. 2. The experimental montage
In fig. 2 we can see the next parts of the experimental montage: 1- the studied metallic
structure (presented also in fig. 1); 2- a Bruel&Kjaer accelerometer with 0,004 pc/ms-2
sensitivity; 3- a notebook; 4- impact hammer Bruel&Kjaer; 5- Spider 8 data acquisition
aparatus; 6- signal amplifyer NEXUS 2692-A-0I4 produced by Bruel&Kjaer. A zoom with
the accelerometer applied on the structure is presented in fig. 3.
Fig. 3. The Bruel&Kjaer accelerometer applied on the structure
We have placed the small accelerometer in several points and excited the structure in
other points. For each excitation condition, the excitation force and the beam acceleration
response were measured
3. Modal identification
We shall consider for this paper the next studying variants: variant 1- point 2
excitation and point 1 measuring; variant 2- point 3 excitation and point 1 measuring.
In fig. 1 we presented the time recorded characteristics for variant 1. We also made a
zoom in the signal area to highlight the impact force (marked with 1) and the beam
acceleration response in point 1 (marked with 2). We abbreviate the frequency response
function with FRF. In fig. 5 and 6 we present the FRF in cartesian and polar coordinates.
In fig. 5 we have the next curves: 1- real part of FRF (red line); 2- imaginary part of
FRF (blue line); 3- power spectral density of excitation (green line); 4- FRF amplitude (black
line); 5- power spectral density of response (pink line).
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In fig. 6 we have used the next axes for the FRF in polar coordinates: the horizontal
axis- real part of FRF (abbreviated with RE_FRF); the vertical axis- imaginary part of FRF
(abbreviated with Im_FRF). In fig. 7 we present a modal parameters panel in the first stage of
identification (as described in chapter 3 from this paper). We have made a zoom in the
graphic area to highlight the next curves: 1- real part of experimental FRF (dotted red line); 2real part of theoretical FRF (continuous red line); 3- imaginary part of experimental FRF
(dotted blue line); imaginary part of theoretical FRF (continuous blue line). In fig 8 we
present the final panel of the modal parameters identification, using the same symbols like in
fig. 7 for the theoretical and experimental FRF. We observe that there are very little
differences between the experimental and theoretical characteristics.
Fig. 4. The time recorded characteristics for variant 1
Fig. 5. FRF in cartesian coordinates for variant 1
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Fig. 6. FRF in polar coordinates for variant 1
Fig. 7. Modal parameters in the first stage of identification for variant 1
Fig. 8. Final modal parameters panel with theoretical and experimental characteristics in variant 1
For the variant 2, we will follow the same steps like above, using the same notations for the
obtained curves. The time recorded characteristics is presented in fig. 9. The FRF in cartesian
and polar coordinates is presented in fig. 10 and 11. In fig. 12 we present the final panel of the
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modal parameters identification, using the same simbols like in fig. 7 for the theoretical and
experimental FRF. We observe that there are very little differences between the experimental
and theoretical characteristics.
Fig. 9. Time recorded characteristics for variant 2
Fig. 10. FRF in cartesian coordinates for variant 2
Fig. 11. FRF in polar coordinates
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Fig. 12. Final modal parameters panel with experimental and theoretical characteristics in variant 2
4. Conclusions
In this paper we have presented the software for the modal parameters identification.
For the two considered variants, we have obtained five modal parameters (variant 1) and four
modal parameters (variant 2). For further analysis, we can excite the structure and measure
the vibratory response in other points. From the fig. 8 and fig. 12 we can observe that between
the theoretical and experimental characteristics exist very small deviations because of the
investigated structure complexity and because in an excitation point ―i‖ and measurement
point ―j‖ configuration, not all the vibration modes are acting as strong, some of them are
hardly to separate.
Applied on a new equipment in the prototype stage, modal identification gives
informations about the corectitude of design conception, construction, and it may give
informations concerning the improvement of the vibration response of the equipment.
This method can be used in parallel with a finite element software. A very good finite
element software can be a certain error source if it is used by an analyst that mindless of the
fact that the material characteristics are only approximate known, even if the geometrical
model is very good.
Applied on a recent mounted equipment, or on a working equipment, the modal
identification gives informations concerning the quality of the mounting process, the
weariness of material, possible cracks or the whickness of some parts.
5. Acknowledgement
This work was partially supported by the strategic grant POSDRU/88/1.5/S/50783
(2009), co-financed by the European Social Fund – Investing in People, within the Sectoral
Operational Programme Human Resources Development 2007-2013.
References
32. Ilincioiu, D., et. al., (2012), Research Regarding the Modal Parameters Identification (I),
SYMECH, Tg-Jiu
33. Adam, C., (2001) Eigenstrain induced vibration of composite plates, Acta Mechanica 148,
35-53
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Editura “Academica Brâncuşi” , Târgu Jiu, ISSN 1844 – 640X
34. Belousov, V., I., et al., (2000) Methods of calculation and parameter control of the
eigenmodes of a simple two-mirror cavity, Radiophysics and Quantum electronics, 43(8),
663-670
35. Cao, X.,et al., (2011) Free vibration of cylindrical shell with constrained layer damping,
Appl. Math. Mech.-Engl. Ed., 32(4), 495-506, DOI: 10.1007/s10483-011-1433-7
36. Chapman, C., L., et al., (2002) Spatial eigenmodes and synchronous oscillation: Coincidence detection in simulated cerebral cortex, J. Math. Biol. 45, 57-78
37. Esmailzadeh, E., Jalali, M., A., (1999) Nonlinear oscilations of viscoelastic rectangular
plates, Nonlinear Dynamics, 18:311-319
38. Hu, M-y, Wang, A-w., (2009) Free vibration and transverse stresses of viscoelastic
laminated plates, Appl. Math. Mech.-Engl. Ed., 30(1), 101-108, DOI: 10.1007/s10483-0090111-y
39. Hu, M-y, et al., (2011) Approximate analytical soluctions and experimental analysis for
transient response of constrained damping cantilever beam, Appl. Math. Mech.-Engl. Ed.,
31(11), 1359-1370
40. Edwins, D., J., (1987) Modal testing, Bruel&Kjaer
41. Jianxin, G., Yapeng, S., (1999) Vibration and damping analysis of a composite plate with
active and passive damping layer, Appl. Math. Mech.-Engl. Ed., 20(10) 10-1075-12
42. Gomez., D., et al., (2008) Fromal asymptotics of eigenmodes of oscillation spatial bodies
with concentrated masses, Journal of Mathematical Sciences, 148(5), 650-674
43. Lee, W-H., Han S-C.,(2006) Free and forced vibration analysis of laminated composite
plates and shells using a 9-node Assumed strain shell element, Comput Mech, 39:41-58, DOI:
10.1007/s00466-005-0007-8
44. Kairov, A., S.,(2001) Effect of holes on the eigenmodes of reinforces shells of rotation,
Journal of Mathematical Sciences, 103(3), 393-397
48
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Editura “Academica Brâncuşi” , Târgu Jiu, ISSN 1844 – 640X
CINEMATIC AND STRUCTURAL PROBLEMS AT A STEPPING
MECHANISM USED FOR TOYS
Prof. PhD. Iulian POPESCU, University of Craiova, [email protected]
Prof. PhD. Liliana LUCA, Constantin Brancusi University of Targu-Jiu,
[email protected]
Prof.PhD.eng.Sevasti Mitsi, Department of Mechanical engineering
University of Thessaloniki, Greece
Abstract. We do a short history of the mechanisms for stepping toys and we analyse such a mechanism from the
structural and cinematic viewpoint, establishing the diagrams of displacements. We also do the movement
simulation. We structurally study a mechanism rotating the head and the eyes of the same toy, by finding a
complicated structure.
Key words: stepping mechanism, toy mechanisms
1. Introduction
In the technique history, we know certain stepping mechanisms used for different toys
[3]. Thus, Leonardo da Vinci in the 16th century built a lion that moved its legs, rotated his
head and his tail a little bit (fig. 1) [5]. It is also known Cebâşev‘s mechanism in fig. 2, that
acted as a toy-horse that moved its legs and stepped [1].
Fig. 1
Fig. 2
After the robots appeared, many works that treat displacement by stepping were
created, by using electro-mechanic actions and electronic commands. In [2] they study
mechanic stability problems of certain stepping devices based on mechanisms. They establish
the moving cycles and elaborate mechanic models that are studied in detail. They present then
the stepping mechanism for a mechanic toy, achieving structural and cinematic studies.
2. Cinematic scheme and the operation of the mechanism
The mechanism of an animal that steps and moves its eyes was studied. The action is
made by a small electric engine powered by batteries.
For stepping, the toy has 4 legs, the legs from behind also have wheels, and also a
platen that rotates around the vertical axis, and it also has two wheels that are made solid by a
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tree that receives the movement from the same cinematic chain as the platen, as the
movements are correlated.
The action block having an electric engine and a reducing tool, rotates the cam 1 (fig.
3) that displaces the tappet 2 forward and backward.
Fig. 3
There are two prominences of the tappet that penetrate, in backlash, the channel of a
connecting rod that makes the legs work.. Fig. 4 gives the cinematic scheme of the
mechanism.
Fig. 4
From outside we receive a translation movement from the tappet. The connection
between tappet 1 and the connecting rod 2 is made by a toy in backlash, so in the cinematic
scheme there is a higher wire of the 4th class in C. Structurally, we replaced the wire of C by
an element 2‘ (fig. 5) and the wires C‘ and C.
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Fig. 5
Fig. 6
Therefore, the resulting structural scheme is given in fig. 6. We find that the stepping
mechanism is formed of a leading element and a triad.
There are two symmetric stepping mechanisms, one of them making the left legs
work, the other one making the right ones work. The maximum rotation angle of the element
DBB1 (fig. 4) is about 40 degrees.
For simulating the leg movement, we considered as known the movement of the
element 3 (fig. 4) and we calculated the movement of BEF.
Fig. 7 shows the successive positions of the left legs.
Fig. 7
Fig. 8 gives the variation curves of the coordinates of points B and B1 (depending on
the rotating angle of the stem DB), and fig. 9 – the curves for the coordinates of the points E
and E1. We may notice that the points representing the tiptoes have negative values, as they
are under the adopted x axis (fig. 4).
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100.
40.
75.
20.
50.
xB [mm]
yb [mm]
xB1 [mm]
yB1 [mm]
25.
xE [mm]
yE [mm]
xE1 [mm]
yE1 [mm]
0.0
0.0
-25.
-20.
0.0
10.
20.
30.
40.
Fi [grd]
0.0
10.
20.
30.
40.
Fi [grd]
Fig. 8
Fig. 9
From fig. 9 it results that, for the vertical position of EF, the abscises are equal; in the
diagram, there is an overlapping of three curves, that is actually an optical illusion, because xF
is in fact 2 mm bigger than FE.
At the same toy, there is also a very complicated spatial mechanism. It is about two
symmetric mechanisms that rotate, with a certain angle, the animal‘s ―eyes‖.
The movement starts from another cam mechanism, symmetric to the previous one.
The tappet of fig. 10 has a small hole in the middle on the right, where the left side of stem 3
enters. This stem articulates at the chassis and makes the ―eye‖ work.
Fig. 10
The movement starts from cam 1 that makes tappet 2 work, and by means of roll it
gets to element 3. The elements 3 and 4 form the oscillating link mechanism of fig. 11.
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Fig. 11
Fig. 12
Up to this point, we met plain mechanisms that were known. The remained
mechanism, FGH is spatial and its leading element is FG with the rotation movement. In H
there is a bolt moving in a very large place. This is associated to the oscillating ―eye‖.
The element 4 is the animal‘s ―head‖ that has an oscillating movement. The place of
the chassis is large also because there is the bolt of the symmetrical mechanism.
By analysing the possible movements for the elements, we found the scheme of fig.
12. It results that the mechanism belongs to the family 1.
The mobility degree is:
M=5n-4C5-3C4-2C3-C2 = 5.2-4.2-0.3-1.1=1, so in H there is a wire of the 2nd class.
3. Conclusions
Based on the facts above, we can establish the following conclusions:
- the toy corresponds to the purpose, meaning that it simulates an animal‘s stepping,
the rotation of the head and eyes;
- the mechanisms are desmodrom;
- the toy contains two interesting mechanisms: one for stepping and another spatial
one for the movement of ―the head and eye‖;
- both of the mechanisms have difficulties at the cinematic calculations;
- the constructor accomplished many wires with backlash in order to obtain the desired
movements, and this is not correct according to Mechanism Theory.
- the constructive solutions based on big backlashes in wires, allow the functioning of
the mechanisms, without imposing a big accuracy.
- the mechanisms were empirically accomplished, but they meet the required
conditions.
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Bibliography
[1] Cebâşev, P.L. Izbrannâe trudî, Moskva, Nauka, 1953.
[2] Coleman, M.J. ş.a. - Prediction of stable walking for a toy that cannot stand. În:
PHYSICAL REVIEW E, VOLUME 64, 022901.
[3] Popescu. I. – Din istoria mecanismelor, vol IV, Editura Sitech Craiova, 2002.
[4] Popescu, I., Luca, L., Cherciu, M. – Traiectorii şi legi de mişcare ale unor mecanisme.
Editura Sitech, Craiova, 2011.
[5] http://re.trotoys.com/article/mechanical-toys-history
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GENERATION OF AESTHETIC SURFACES THROUGH TRAMMEL
MECHANISM
Prof. PhD. Liliana LUCA, Constantin Brancusi University of Targu-Jiu,
[email protected]
Prof. PhD. Iulian POPESCU, University of Craiova, [email protected]
Abstract: It is being made the geometric synthesis of trammel mechanism, and structural and kinematics
analysis. They generate ellipses and the successive positions of mechanism, observing that some figures are
aesthetic. Performing additional rotations of ellipses, they result aesthetic surfaces .
Keyword: trammel mechanism, aesthetic curves and surfaces.
1. Introduction
Drawing conics is necessary both to design and in workshops. Thus, are usual cases
whern you should cut elliptical plates, which must first be traced or drawn to scale for
oxyacetylene cutting after drawing. They are also necessary the conics generation
mechanisms, for operations of welding of caps or flanges, using automatic welding devices.
Such operations are still widespread, even if today there are machines with numerical
command or special plotters.
Conicograf mechanisms have long been known, being widely studied in terms of
geometry. Although based on simple mathematical theories, these mechanisms result quite
complicated, raising issues in their analysis and synthesis.
Recently, they expanded the research on the aesthetic effects of curves and surfaces.
Thus, Kanaya makes a classification of aesthetic curves and surfaces with applications in
design (CAD). They are given the mathematical relations of some aesthetic curves,
exemplifying their application in car‘s forms. Miura is studying the aesthetic aspect of
logarithmic spiral, clothoid and involute curves.
They also analyze the properties of these curves based on differential geometry,
indicating the mathematical generation manner, point by point. It is being exemplified by the
usage of these curves to the shaping of some musical instruments, car carcasses and as models
in the textile industry field. Yoshida examines a method of interactively control of aesthetic
curves and surfaces, by analyzing the positions of normality and binormality, the curvature,
the torsion, giving numerous tabulated examples. Trammel mechanisms have been studied by
Artobolevskii, Tutunaru, Smith and others. Below are studied two trammel mechanisms
andthey are shown some aesthetics forms generated by them, and by further rotation resulting
aesthetic surfaces.
2. The trammel mechanism
It is known that Cardan's problem if a line ends moving axes x and y, then its points
describe ellipses.
If axis x1 ≠ x and y are not perpendicular, in [6] shows that all results conicograf
mechanism (Fig. 1).
Based on Fig. 1, we write the relations:
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Fig. 1
Fig. 2
For other dates (L,  , AM) they resulted: fig. 2, 3 (L=30,  =30, AM=30), fig. 4, 5
(L=30,  =20, AM=40).
Fig. 3
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Fig. 4
Fig. 5
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For point C taken off the distance AB we can observe the ellipse described by the AC
segment (Fig. 6 (L=35,  =45, AM= - 25), Fig. 7 (L=30,  =30, AM= - 30)).
Fig. 6
Fig .7
Note that some of the figures above have aesthetic forms.
3. Other visual effects
If the x axis in Fig. 1 is rotating around the y axis, then an observer which views
from the z axis which is perpendicular to x and y, will see in xoy plane a series of ellipses that
form a surface.
Thus, for the case in Fig. 4 it resulted the image in Figure 8.
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Fig. 8
Fig. 9
For Fig. 6 was obtained the surface from fig. 9.
The generated ellipse in Fig. 7, by rotation, generated the surface in Fig. 10, with the
intermediate phase in Fig. 11.
Fig. 10
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Fig. 11
It was also generated an area (L= - 50,  = - 30, AM= - 25), which is given in Fig. 12,
as intermediate phase, respectively in Fig. 13, as the final form.
Fig. 12
Fig. 13
If for the mechanism in Fig. 1, the resulting ellipse rotates around the x axis, aesthetic
surfaces are obtained Fig. 14, for the curve in Fig. 6. Also in order to emphasize aesthetics,
were not traced the axes of the coordinate system.
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Fig. 14
If for the mechanism in Fig. 1, the resulting ellipse rotates around the z axis, aesthetic
surfaces are obtained as follows: Fig. 15, for the curve in Fig. 4 and Fig. 16, for the curve in
Fig. 6.
Fig. 15
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Fig. 16
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Each right of these last images represents an ellipse in the plane perpendicular to the
drawing.
4. Conclusions
- They have been presented one simple mechanism that trace ellipses.
- This mechanism are based on geometric properties: Cardan's circle and the ellipse
graphical construction.
- There have been realised programs with which they have been drawn different
ellipses and the successive positions of the generating mechanisms.
- Aesthetics forms were obtained by rotating mechanisms around the axis system.
References
[1]Artobolevskii, I.I – Teoria mehanizmovdlia vosproizvedenia ploskih crivâh. Izd.
Academii Nauk, SSSR, Moskva, 1959.
[2]Kanaya, I., Nakano, Y., Sato, K. – Classification of aesthetic curves and surfaces
for industrial designs. În: Design Discourse vol. II, 4 aprilie 2007
[http://designhistoryforum.org/dd/papers/vol02/no4/02_4_1.pdf].
[3]Yoshida, N., Fukuda, R. Saito, T. - Log-Aesthetic Space Curve Segments. În:
SIAM/ACM Joint Conference on Geometric and Physical Modeling, 2009, pp.35-46.[
http://www.yoshida-lab.net/english/research-e/log-aesthetic-curves/]
[4]Miura, K., Agari, S., Kavata, Y., Fujisawa, M., Cheng, F. - Input of Log-aesthetic
Curve Segments with Inflection End Points and Generation of Log-aesthetic Curves with G2
continuity. În: Computer-Aided Design and Applications, 5(1-4), 2008, pp. 77-85.
[http://www.cadanda.com/CAD_5_1-4__77-85.pdf]
[5]Popescu, I., Sass, L. – Mecanisme generatoare de curbe, Editura Scrisul
Românesc, Craiova, 2001.
[6]Tutunaru, D. – Mecanisme plane rectiliniare şi inversoare. Editura Tehnică,
Bucureşti, 1969.
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Editura “Academica Brâncuşi” , Târgu Jiu, ISSN 1844 – 640X
A STUDY ON THE WHEELSET/SLAB TRACK
VERTICAL INTERACTION
Associate Professor PhD. eng. Traian MAZILU
Department of Railway Vehicles, University Politehnica of Bucharest
313 Splaiul Independentei, sector 6, 77206, Bucharest, Romania
[email protected]
Abstract This paper deals with the interaction between a moving wheelset and a slab track due to the shortpitch corrugated rail. The wheelset is modeled using a free-free Timoshenko beam with attached rigid bodies as
the axle boxes, wheels and brake discs. The slab track model consists of elastically supported double EulerBernoulli beams. In fact, both wheelset and slab track are symmetric structures and the issue of the
wheelset/slab track interaction is reduced to the wheel/rail interaction. The nonlinear equations of motion
describing the wheelset/slab track interaction due to the short-pitch corrugated rail are solved using the timedomain Green’s functions method and the convolution theorem. The wheelset/slab track interaction due to the
short-pitch corrugated rail exhibits a critical velocity when the vibration reaches the maximum level.
Keywords: wheelset, slab track, short-pitch corrugated rail, Green‘s functions
1. Introduction
This paper showcases a study of the interaction between a wheelset and a slab track
when considering the input due to the short-pitch corrugated rail. These aspects of the
wheelset/slab track interaction are critical in predicting the rolling noise [1], the ground
vibration [2] or the formation and developing of the short-pitch rail corrugation [3].
The slab track is seldom preferred for the high-speed lines crossing region with soft soil
because it is able to isolate the rail vibration from the subgrade influence, mainly when the
trains‘ velocity and the phase velocity of the waves induced by the trains in the track structure
are closed. Similarly, the slab track is extensively applied for urban railway transport [4]. In
virtue of the symmetry feature, the slab track model is usually reduced to a rail resting on a
slab via rail pad, both taken as Euler-Bernoulli or Timoshenko beams [5].
For the middle and high frequency range, the issue of the vehicle/track interaction is
solved by reducing the vehicle to a wheel. The lumped mass model [6] and two-mass
oscillator [7] are the usual models for the wheel. Likewise, there are models that include the
bending modes due to the axle or the radial modes of the wheel itself [7]. These models are
either discrete-continuous or FE models like the ones used by Szolc [9] and respectively,
Diana et al [10] to study the vibration behavior of the ballasted track.
In this paper, the interaction between a moving wheelset and a slab track is investigated
using the time-domain Green‘s functions for both wheelset and slab track, which are suitable
to account for the nonlinear wheel/rail contact [11, 12]. The wheelset is modeled using a freefree uniform Timoshenko beam as the axle, with attached rigid bodies as the wheels, axle
boxes and brake discs. Only the symmetric bending modes are taken into account. The model
of the slab track consists of two infinite uniform Euler–Bernoulli beams coupled by a Winkler
layer as the rail, slab and the rail pad, respectively. Similarly, the ground is taken as a Winkler
foundation. Finally, the results from the numerical simulation of the interaction between the
wheelset and the slab track due to the short-pitch corrugated rail are presented.
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2. The vehicle mechanical model
It considers the case of one wheelset that rolls without slip at the constant velocity V
along a tangent slab track as depicted in fig. 1. Both wheelset and slab track (including the
irregularities of the rolling surfaces and the loading of the wheel/rail contacts) are presumed
as symmetric structures. Subsequently, only half of the slab track needs to be modeled and the
dynamics of one wheel considering the symmetric modes of the wheel set have to be
accounted for.
Fig. 1. The wheelset/slab track mechanical model: (a) wheelset/slab track system; (b) wheelset.
Sticking with the general domain, we refer to one wheelset of a passenger coach with
two wheels, two axle boxes and two brake discs, as well. The model of the wheelset consists
of a uniform Timoshenko beam as the axle, with attached rigid bodies as the wheels, the axle
boxes and the brake discs (fig. 1 (b)). The displacements of the axle are described by the
column vector qw(y, t) = [v(y, t) (y, t)]T, where v(y, t) and (y, t) are the vertical
displacement and the rotation of the cross-section; t and y stand for the time and the
coordinate along the axle, respectively. The parameters of the axle are: the Young‘s modulus
E, the shear modulus  the density ,he
t length l, the mass per length unit ma, the crosssection area Sa, the area moment of inertia Ia and the shear coefficient a. The rigid body i (i
= 1÷6) is attached to the axle at the distance ei from the left end of the axle and has the Mi
mass and the Ji mass-moment inertia.
The wheelset is subjected to static loads F0 applied on the two axle boxes by the
suspended mass of the vehicle, the wheelset weight Gw and two equal contact forces Q(t)
including the static component Q0 (Q0 = F0 + Gw) and the dynamic one. It is quite obvious that
these two forces act on the wheels and are located at the distances e2 and e5, respectively. For
that reason, only the symmetric vibration modes are involved.
Assuming the hypothesis of the small motions about the equilibrium position and
neglecting the gyroscopic effects and the static and dynamic imbalances of the wheelset, the
governing equations of motion may be written as follows:
6
Lwy, t q w ( y, t )   Fi, t q w (ei , t )( y  ei )  Q w ( y, t ) ,
(1)
i 1
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qw(ei, t) is the column vector which contains the axle displacement in the ei section, Qw(y,t) =
(Q(t) –Q0)[y 0]T is the column vector of the forces which act on the wheelset with y=(y–
e2)+(y–e5) and (.) as the Dirac‘s delta function, and Lwy,t and Fi,t stand for the matrix
differentials

2
2
S a  a 2  ma 2
y
t
Lwy ,t  


S a  a
y




2
2



EI a
 I a
 S a  a 

y 2
t 2

d2
M i 2
dt
Fi, t  

 0

 S a  a

y


.
2 
d
Ji

dt 2 
(2)
0
(3)
Such model gives enough accuracy as long as the wheel rim and the disc vibrate
together, which means that the frequency is up to 1500 Hz [23].
The boundary conditions (free-free) require that the shear force and the moment are null
for both ends of the axle (y = 0 and y = l)
v

  0,
0
y
y
(4)
The slab track is considered to be an infinite, homogeneous structure and its model (half
track) may be reduced to double Euler–Bernoulli beams coupled with a Winkler layer, due to
the symmetric structure hypothesis. The loss factor for both beams is neglected. It is assumed
that the wheelset velocity is lower than the minimum phase velocity of the waves excited in
the ground and, because of that, the ground is looked at as a Winkler foundation.
One the other hand, it has to be mentioned that the Euler-Bernoulli beam model gives
satisfactory results as long as the cross-sectional dimensions are small compared to the
bending wavelength. The parameters for the slab track model are: the mass per length unit
m1,2 (index 1 for upper beam and index 2 for under beam) and the bending stiffness EI1,2. The
two Winkler foundations have the elastic constants k1,2 per length unit and the viscous
damping factors c1,2 per length unit.
The track‘s differential equations of motion can be written in matrix form as
L x0 ,t w( x0 , t )  Q( x0 , t ) ,
(5)
where L x0 ,t stands for matrix differential operator
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
4
2

EI

m
 k1
 1 4
1 2  c1
t
x0
t

L x0 , t  


 c1  k1
t




 , (6)
2


 m2
 (c1  c2 )  (k1  k 2 )
t

t 2
 c1
EI 2
4
x04

 k1
t
w(x0,t)=[w1(x0,t)
w2(x0,t)]T is the column vector of the beams displacements and
Q(x0,t)=[Q(t)(x0–Vt) 0]T is the column vector of forces on the track.
The boundary conditions are
lim
x0 Vt  
w( x0 , t )  0 0T
(7)
and all initial conditions are zero, including the Q(0) normal contact force.
The wheel and the rail are solid elastic bodies and the Hertz‘s theory of elastic contact
may be applied for the wheel/rail deformation at contact point. By neglecting the wheel radius
influence on the contact position, the wheel/rail normal force will be expressed as
Q(t ) / CH 2 / 3  z (t )z (t ) ,
(8)
where CH represents the Hertzian constant, [.] is the Heaviside function and z is wheel/rail
deflection, including the irregularity of the rolling surface.
It has to be underlined that the two subsystems – the wheelset and the slab track - are
represented by the linear models and this fact allows to highlight their response, using
adequate forms of the Green‘s functions.
3. The estimation of the dynamic forces at a railway vehicle
In this section, both the random behavior and the time-domain numerical analysis of a
particular wheelset that uniformly moves along a slab track are presented. The model
parameters for the wheelset and the slab track are presented in ref. [11] and [12].
Fig. 2. The wheel/rail interaction due to the corrugated rail (amplitude of 30 µm and wave
length of 80 mm) at 84 m/s: (a) , rail displacement at the moving contact point, , wheel
displacement; (b) , contact force, , static load.
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The Hertzian constant CH = 9.42∙1010 N/m3/2 is determined by taking the curve radiuses
of the UIC 60 rail-type and the radius of 0.46 m for the wheel (conic profile). The stiffness of
the wheel/rail contact has the value of 1.338 GN/m.
Fig. 3. Contact force versus wheelset velocity: (a) •, maximum contact force;
*, minimum contact force; – – –, static load; (b) o, asymmetry ratio.
As it is known, the rail corrugation is a specific defect of the rail rolling surface with the
wavelength between 3-4 cm and 2-3 m. Critical for the vibration level is the short pitch
corrugation with the wavelength of 30-100 mm. To illustrate the wheelset/slab track
interaction due to the short pitch corrugation, we look at the case of the wheelset rolling on
the corrugated rails with the wavelength of 80 mm and the amplitude of 30 m. Figure 2
shows the numerical results of the steady-state interaction derived from the above model
when the wheelset velocity is 84 m/s (302.4 km/h). For this velocity, the vibration frequency
due to the short pitch corrugation of the 80 mm wavelength is 1050 Hz. Upon comparing the
average value of the wheel displacement and rail‘s at the moving contact point, it may be
observed that the wheel displacements are higher due to the contact elasticity. On the other
hand, the rail amplitude is significantly higher than the wheel‘s one and this aspect is
consistent with the results obtained via the frequency-domain analysis. It is worthwhile
mentioning that the wheel and rail at the moving contact point are in antiphase, which
explains why the contact force reaches values so high (see Fig. 2 (b)). The peak of the contact
force is 148.4 kN and the minimum contact force value is 7.8 kN. By comparing these values
with the static load of 70 kN, the nonlinear character of the wheel/rail vibration is obvious.
The asymmetry ratio may be introduced as the ratio between the high and low amplitudes of
the contact force during a cycle. The asymmetric ratio reflects the nonlinear character of the
vibration. It has to be observed that the nonlinear Hertzian contact has a hardening
nonlinearity and, because of that, when the wheel is moving downwards, the contact force
increases higher than it decreases during the upwards motion of the wheel.
Finally, the influence of the wheelset velocity on the maximum/minimum contact force
value when the wheelset rolls over the corrugated rail is displayed in Figure 3 for velocities
between 40 and 100 m/s. In this figure, the asymmetry ratio may be also found for the same
velocity interval. The level of the vibration behavior increases along the velocity and reaches
the highest level at 84 m/s. Then, at higher velocities, the vibration level decreases. This fact
corresponds to the results derived from the frequency-analysis, where the contact force
exhibits a relative flattened peak around 1050 Hz. The nonlinear character of the vibration
becomes more evident at the velocity of 84 m/s.
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6. Conclusions
Here, the time-domain analysis of the wheelset/slab track interaction behavior has been
performed by taking into account the nonlinearity of the wheel/rail Hertzian contact.
The wheelset is modeled as a free-free Timoshenko beam as the axle, attached rigid
bodies as the axle boxes, wheels and brake discs. The mechanical structure of the wheelset is
symmetric and consequently, the symmetric bending modes of the wheelset only are
considered. Also, the slab track is supposed to be a symmetric infinite structure and its model
consists of elastically supported double Euler-Bernoulli beams. The upper beam models the
rail, the lower is for the slab, while the two elastic layers represent the rail pad and the
subgrade.
The wheelset/slab track interaction might be strongly influenced by the contact
nonlinearities, such as the non-linear contact stiffness according to the Hertz theory. When
the wheelset rolls over a short-pitch corrugated rail, the level of the wheelset/slab track
vibration increases along the wheelset velocity and reaches a maximum level at a particular
velocity. The vibration nonlinear character is visible thanks to the asymmetry ratio that
exhibits the maximum value when the vibration level is the highest.
References
[1] Remington, J.P., Wheel/rail noise—part I: theoretical analysis, J. Acoust. Soc. Am. 81, (1987),
1805–1823.
[2] Metrikine, A.V., Popp, K., Steady-state vibrations of an elastic beam on a visco-elastic layer
undermoving load, Arch. Appl. Mech. 70, (2000), 399–408.
[3] Nielsen, J.C.O., Lundén, R. Johansson, A. Vernersson, T., Train–track interaction and
mechanisms of irregular wear on wheel and rail surfaces, Veh. Syst. Dyn. 40, (2003), 3–54.
[4] Esveld, C., Track Structures in an Urban Environment, TU Delft, Symposium K. U. Leuven
(1997).
[5] Hussein, M.F.M., Hunt, H.E.M., Modelling of floating-slab tracks with continuous slabs under
oscillating moving loads, J. Sound Vib. 297, (2006), 37–54.
[6] Grassie, S.L., Gregory, R.W., Harrison, D., Johnson, K.L., The dynamic response of railway
track to high frequency vertical excitation, J. Mech. Eng. Sci. 24, (1982), 77–90.
[7] Nielsen, J.C.O., High-frequency vertical wheel–rail contact forces-validation of a prediction
model by field testing, Wear 265, (2008), 1465–1471.
[8] Thompson, D.J., Wheel–rail noise generation, part II: wheel vibration, J. Sound Vib., 161,
(1993), 401–419.
[9] Szolc, T., Simulation of bending-torsional-lateral vibration of the railway wheelset-track system in
the medium frequency range, Veh. Syst. Dyn., 30, (1998), 473–508.
[10] G. Diana, F. Cheli, S. Bruni, A. Collina, Exprimental and numerical investigation on subway
short pitch corrugation, Veh. Syst. Dyn. Suppl., 28, (1998), 234–245.
[11] Mazilu, T., Dumitriu, M., Tudorache, C., Sebeşan, M., Using the Green’s functions method to
study wheelset/ballasted track vertical interaction, Math. Comp. Mod. 54, (2011), 261–279.
[12] Mazilu, T., Interaction between a moving two mass oscillator and an infinite homogeneous
structure: Green’s functions method, Arch. Appl. Mech., 80, (2010), 909-927.
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DETERMINING THE RESPONSE IN CASE OF VIBRATIONS OF
STRAIGHT BARS WITH RANDOM EXCITATIONS
Ph.D.Lecturer Monica BALDEA,Faculty of Mechanics and Technology,University of
Pitesti,e-mail:[email protected]
Abstract:By applying the finite element calculus to the study of bar vibrations, one obtains a system of linear
diferential equations. One carries out the determination of the response to random stimulations by calculating
the statistical terms as a function of the statistical terms of the stimulation.
Key words:random,vibrations, bar, response.
1.Introduction
The exact mathematical model of the bars vibrations leads, as we know, at solving some
partial derivative equations.
The difficulties we come across solving this equations start from the limit conditions as
well from the stimulation that solicits the bars.
Paper [5] shows that the difficulties concerning the limit conditions can be avoid by using
the finite element calculus. The paper which we present shows that by applying the finite
element calculus we can avoid the difficulties concerning stimulations too, especially the
random ones, in which the response must be expressed in stimulation statistic terms.
2.Differential equation of the finite element (the finite elements differential equations)
Let s take a straight bar constant section, with area A and length L and AiAj the finite
element with length l noted with index p.
We will note OXYZ the reference system, and Ai xyz the local reference system, and Ai
xyz the local reference system.
During the following equations we will study only the bars plane vibrations.
We will use for the knots Ai Aj displace in the local reference system, the notes
(1)
And for the knots Ai Aj faces the notes
(2)
If m is the finite elements mass, E the longitudinal elasticity module I the inertia moment
from the normal sections Aiz axis, than based on the notes from paper [5]
(3)
We obtain the inertia matrix
(4)
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(5)
and the rigidity matrix:
(6)
(7)
The differential equations of the finite elements vibrations, in the local reference system
are the same in this case with the differential equations from the general system
(8)
3.Equations assembly
If in the Ai knots the external forces Pi operates (acts) and the use notes
(9)
Taking into account the equality
For the knot Ai we obtain the equation
(10)
The relations written for all the non-zero displacement knots can be written in one matrix
equation
(11)
Where M is the bars inertia matrix K is the bars rigidity matrix
is the displacement
vector and P the stimulations vector
So for the bar embedded at the ends from considering only three finite elements
(12)
(13)
(14)
;
(15)
If we consider that all free finite elements have the same length than by noting the bars
length l and the bars mass m results
(16)
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(17)
(18)
(19)
(20)
Considering the first and fourth scalar equation resulting from the (11) equation, we
obtain the system
(21)
Result in system (21) beats value:
(22)
Which is very similar to the exact value[6]
4.The response to random stimulation
Lets further consider that stimulation{P}from the (11) equation is a stationary random
vector function and ergodic and lets determin the responses terms.
We calculate the transfer matrix
(23)
and considering that the interspectral density matrix of power is know, results[ 4]:
-mean value vector
(24)
-interspectral density matrix
(25)
where H is the [H] matrix conjugated
-effective value
(26)
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Bibliography
[1] Buzdugan Gh. ,Fetcu L., Rades M., Vibrations of mechanical systems, Bucharest
Academy Publishing House,1975
[2] Cuteanu E., Marinev R., Finite element method in design of structures,Facla Publishing
House,Bucharest,1980
[3]Marinescu G.,Ivan C., Finite Element Method, C.I.A.Publishing House,Bucuresti,1996
[4]Munteanu M.,Introduction in the dynamics of solid rigid oscillations and of solid rigid
systems,ColoseumPublishing House, Cluj Napoca,1977
[5]Pandrea N.,Rizea V., Finite Element Method. Concepts and aplications, Publisher
University of Pitesti,1998
[6]Pandrea N., Parlac S.,Mechanical vibrations ,Publisher University of Pitesti,2000
[7]Baldea M.,Linear-elastic vibrations of mechanical systems with random excitation,
Publisher University of Pitesti,2008
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THE THEORETICAL CRITERIA ON THE VAPORIZATION AND
COMBUSTION RATES OF EMULSIONS WATER
IN HEAVY FUEL OIL
Ph. D. Corneliu MOROIANU
Naval Academy of Constanţa, E-mail: [email protected]
Abstract: The vaporization and combustion characteristics of a heavy oil-water emulsion droplet are
investigated with graphological method. The combustion graphology of fuel oils is defined as a new technical
and scientific field which deals with the graphic transposition of the processes of fuels combustion development
in a simulator. Thus, it is easy to establish the ignition-combustion characteristics, including the laws that
govern their changes depending on the combustion conditions and fuel specifications.
Keywords: oil-water emulsion, vaporization, graphological method.
1. INTRODUCTION
In the actual process of development of technologies for obtaining liquid fuels we can
mark out two main classes: the class of liquid fuels with cenosphere and the class of liquid
fuels without cenosphere. In the former class, the so-called intermediate and heavy fuels
which resulted from the mixture in different proportions between the residues obtained from
the oil processing (air distillation, vacuum distillation, analytic cracking, thermal cracking,
etc.) and light products. According to the combustion particularities, they have a similar
behavior, both of them belonging to the class of fuels with cenosphere. In the latter class, they
are included Diesel oil, lamp oil, methanol, etc. The reduction of distillates in the mixture
makes worse their quality by appearing in their composition of a high content of Conradson
coke and asphaltenes, by increasing the viscosity, the content of ash, sulphur and suspended
mechanical particles.
Oxides of nitrogen (NOx) emissions from ship engines and boilers are significant on a
global level. NOx emissions participate in the formation of photochemical smog and acid rain.
Marine sourced emissions have significant impact on air quality on land. The challenge is to
control NOx emissions without increasing fuel consumption and smoke. The slow speed
diesel engines and boilers tend to produce higher NOx emissions than the medium speed ones.
The ship engines are very fuel efficient but have a relatively high output of NOx emissions.
They use very poor quality fuel for economical reasons (heavy fuel oil). The introduction of
water into the combustion chamber for engines and boilers ships reduces the combustion
temperature due to the absorption of energy for evaporation and it increases the specific heat
capacity of the cylinder gases. The water can be introduced in the charge air (humidification)
by direct injection into the cylinder or by water/fuel emulsion. The water/fuel emulsion can
reduce smoke while humidification can increase smoke. The water/fuel emulsions place the
water more directly in the combustion area where it has the maximum effect on NO x
generation.
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2. THE THEORETICAL CRITERIA ON THE
COMBUSTION RATES OF LIQUID FUEL DROPLET
VAPORIZATION
AND
The accurate combustion test for gas oil determines the economic improvement of their
quality. Although. In the early, it had a large field of application, the combustion graphology of
fuel was defined as the scientific branch concerned with the graphic transposition of these fuel
combustion processes, establishing the ignition-combustion characteristics including the laws
which govern their change, depending on the combustion conditions and the chemical structure
of the liquid fuels. The graphological ignition-combustion characteristics of the liquid fuel result
from the interpretation of the combustion oscillogram which is experimentally obtained. The
need for increasing the degree of marine fuel combustion with and without cenosphere, imply
the water emulsification of fuel for obtaining the secondary atomization. This paper deals
with finding new methods and means for improving the combustion processes of marine
liquid fuel. It tries to make evident the effects of water emulsion on the marine liquid fuel
during combustion. The assessment of emulsification influence was made by comparing the
combustion performance and the results with those obtained in the absence of emulsification
under the same test conditions. The laboratory researches developed on the isolated droplet
burning had in view to state the measure in which the emulsification would interfere for
carrying out the secondary atomization [1]. We also tried to determine the characteristics of
induced flames following their configuration and radiation and to assess the igniting and
burning behavior of droplets by laying down comparison criteria of the following times:
i - self-ignition delay, the time betwen the moment of introduction inside the
combustion chamber and the ignition of the droplet which is marked by the appearance of
flame;
 v - burning time of volatile matters;
c - burning time of cenosphere.
2.1. Self-ignition delay time i
The physical model for theoretical calculation of self-ignition time [1]:
i 
L v ( r0  ri )
 Tm  4  T0  4 
r Cr 
 
    c Tm  T0   Ca Q
 100   100  
(1)
The theoretical expression of time i shows that its value can be reduced by increasing the
ambient temperature of droplet, the coefficient of heat-transfer from the gas flowing around
the droplet to its surface, the oxygen concentration of droplet environment, the constant of
reaction rate, the quantity of heat released up to the flame ignition and by decreasing of the
droplet initial diameter and the latent heat of vaporization and the liquid fuel density as well.
2.2. Burning time of droplet a
The burning of residual fuel droplet is achieved in a period of time given by [1]:
a = v + c, (s).
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(2)
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where: v - is burning time of volatile matters;
c - burning time of cenosphere.
The life of droplet e is longer than the burning time because it also includes the self-ignition
delay times i.
e =i + a, (s).
(3)
The liquid fuel droplet is considered a porous sphere in the middle of which the liquid
volatile matters are concentrated. By vaporization and porous mass diffusion the volatile
matters get out of the burning range and burn. After consuming the volatile matters, the
carbon porous lattice also burns due to the oxygen diffusion from the environment to its
surface.
2.3. Burning time of volatile matters  v
Based on the usual physical model, the theoretical relation for calculating the burning
time of volatile matters was determined by [1]:
M 
v  v 
2
 100  2 d 0
v 
do 
P
Kv
8C 0 0
v
,
(4)
where:
ρν - is the density of liquid volatile matters (kg/m3);
Mν - the content of volatile matters (%);
μv - coefficient of dynamical viscosity of volatile matters (kJ/kg K);
d0 – initial diameter of droplet (mm);
C0 - on the surface of porous lattice where r = r0 the volatile matter concentration is c =
0 and for r = rν the concentration is c = c0;
Kν - vaporization constant of volatile matters, depending on the chemical analysis of
liquid heavy fuel and the characteristics of oxygen carrier medium as well.
The decrease of time τν is made by reducing the initial diameter of droplet and by increasing
the ambient temperature as well and the initial diameter of droplet decreases by increasing the
content of volatile matters in the fuel.
2.4. Burning time of cenosphere c
After burning of volatile matters the carbon spherical porous lattice with diameter dc
remains to burn at the surface due to the oxygen diffusion from the environment to it [1]:
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 M 
 c 1  v 
d 02
 100 
2
c 
d

0 , 75 c
Kc
 Tm 
3 0 D 0 C a  
 T0 
(5)
where:
ρc - is the density of cenosphere (kg/m3);
ρ0 - density of gaseous fluid;
D0 - diffusion coefficient of nitrogen at T0 = 273 (K), (m3/s);
Tm- absolute average temperature of gaseous fluid surrounding the droplet (K).
The burning time of cenosphere τc decreases with the temperature rise and the increase of
oxygen concentration in the environment around the droplet and with the increase of the
diffusion coefficient of oxygen as well [1]. The self-ignition delay time of cenosphere τic was
experimentally stated by the period between the completion of volatile matters flame burning
and the self-ignition of carbon residues.
a = i + v + ic + c.
(6)
3. THE COMBUSTION CHARACTERISTICS OF A HEAVY OIL-WATER
EMULSION DROPLET INVESTIGATED
The combustion oscillogram is the graphic transposition of the development of the
ignition and, combustion processes of a liquid fuel droplet under the shape of a curve
represented in coordinates of axes of a rectangular system. The τ-time variation is represented
on the abscissa and the I-radiation intensity variation of the burnt droplet on the ordinate, the
radiation being transformed into voltage through a photoelectric cell with amplification, the
latter receiving the light-infrared signals
The graphic representation of the combustion processes development for a droplet of
liquid fuel used in the industrial combustion can be made by means of the so-called
"combustion oscillogram" (fig. 1).
This graphic representation specifies the time variation of the light-thermal energy radiation
intensity I, for a burning droplet, transformed into electric signals.
Ic [mv]
Iv [mv]
Iv = f(τ)
c
Ev  k  f d
0
0
i
a
Ec  k
c
 v b 
c  
Ic = F(τ)
 F d
0
c
d
τ[ms]
a
e
Fig. 1. The combustion oscillogram.
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From (fig.1) we can see that the energy (power) radiated by the volatile matters Iv =
f() is much higher than the energy of cenosphere represented on the scale by the area under
the curve Ic = F().
Thus, for a heavy fuel oil, this ignition and combustion graphic representation
establishes, under standard conditions: the self-ignition delay τi, the volatile matters
combustion time τv, the cenosphere combustion time τc, the maximum radiation intensity
obtained at the combustion of the cenosphere Ic, the maximum radiation intensity obtained at
the combustion of the volatile matter Iv, the energy radiated by the burning of volatile matters
Ev and cenosphere transformed by the photocell into electric energy Ec, etc. Tf = Ψ(τ) is the
temperature characteristic of the combustion.
c
E v  k  f d
(6)
0
Ec  k
c  
 Fd
(7)
0
4.CONCLUSIONS
The initial strain of the droplet under the action of water vapors contained in the emulsion, it
is followed by its breaking in more droplets of smaller diameters. The smaller values of I c ,
E c and c for C3 fuel droplet as compared to the samples C1, C2 and the sudden variation in
temperature Tf , make evident the possibility of reducing the losses by unburnt carbon,
therefore, the decrease of carbon black (soot) quantity released in the flame leads to the
increase in burning performance of cenosphere, as a result of the secondary atomization. The
combustion of a water-in-oil emulsion is a result of the explosive vaporization caused by
rapid heating of the water dispersed within the individual fuel droplets. The internal water
droplets undergo spontaneous nucleation of steam bubbles, causing a violent conversion of
the water droplet to steam. The vaporization, in turn, produces a rapid expansion of the
surrounding oil droplets, fragmenting the oil into a vast number of smaller fuel droplets. The
name for this process is secondary atomization.
REFERENCES:
1. Law C. K., Combustion Characteristics of Water in Oil Emulsion Droplets, Combustion
and flame, USA, 1980, p. 13-18.
2. Ghia V., Combustion Graphology of intermediate Fuel Oil, Rev. Rom. Sci. Techn.
Electrotechn., t. 36, nr. 3, p. 379-396, Bucharest 1991.
3. WILLIAMS A., The mechanism of combustion of droplets and sprays of liquid fuels,
Oxidation and Combustion Reviews 3, USA,1968, p. 14- 19.
4. Moroianu C., Arderea combustibililor lichizi în sistemele de propulsie navale, Ed.
Academiei Navale ―Mircea cel Bătrân‖ Constanta, 2001., p 34-38.
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DYNAMIC ANALYSIS OF A CRIMPING DEVICE WITH
MULTIPLE CAMS USING MSC ADAMS
Part I. Implementation of the mechanisms with cams in the crimping
of electric detonators
Prof. Univ. Dr. Eng. Gheorghe Popescu,
University ―Constantin Brâncuşi‖ of Târgu Jiu
e-mail: [email protected]
Abstract:
In the present paper, the author presents the result of the researches realized to realize a
tightening device with 12 cams to crimping electrical detonators. This can work singular in vertical position,
through the agency of a sprocket wheel mechanism or in tandem with another cam device, both auctioned by a
sprocket wheel mechanism – cog rack with symmetrical profile. By the application of this device in series
production can be obtained an efficient character of crimping in the process of explosions alienation by dynamic
tearing of rheophore, as well as against of water penetration inside detonator.
Key words: Crimping, electrical detonator, mechanism with multiple cams, bac, avulsion conductors.
1. Introduction
Electric detonators used in shoot activities, have in their composition the pyrotechnical
detonator and the combustion electrical device [3,4].
The assembly of these two components can be realised by the crimping of the metallic
tube of the detonator on the obturator of the combustion electric device, so that the spreading
of their rheophores by the miners and the building-up of explosive loads, not to produce
intempestive explosions.
Also, in case mine holes are full of water, the detonator should enure the tightness of
the explosive loads in respect of them.
Crimping it is realized commonly, with a device of 12 crimping tanks and 3-4 rows of
ribs on bac.
Figure 1. Crimping with several connection rings.
Taking into account the fact that the obturator confectioned from plasticised PVC can
have an elasticity coefficient different from batch to batch, in an indispensable manner there
appear deficiencies of qualitative order in realising the crimping operation.
According to the paper [3] the crimping diameter varies between 4.2 and 5.4 mm.
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Starting from these aspects, the author from the present paper, presents the dynamic
analyze with MSC ADAMS of the mechanism of a crimping device with 12 connection cams,
designed by the author and used in the technological process of assembly of indigenous
electrical detonators.
2. Crimping notion
Crimping is the technological operation through which is realized the plastic
deformation of the copper, aluminum or steel metallic tube, on the obturator cork, through
which are passing electrical conductors, having as effect the consolidation and perfect
tightening of the interior of the detonator, against humidity.
Two procedures of detonator‘s crimping procedures:
- crimping with several connection rings (figure 1);
- doubling crimping (figure 2).
Figure 2. Contortion crimping.
The crimping with several tightening rings is the spreadest procedure and can be
realized with the aid of some devices of radial tightening, auctioned with mechanisms with
cams, plumes and inclined plan or conic mechanisms[3].
Bac‘s penetration depth varies from 1.25 mm to 1.55 mm and it is realized depending
on the number of circles that are used, the shape of the tanks, plasticity of the obturator cork
and disturbances that can be produced in the area of assembly of the rheophores.
The tightening force of each bac can be allocated uniform on each tightening circle.
3. Proposed experimental pattern
The author has designed and realized practical the experimental pattern of a crimping
device for detonators with 12 tightening bacs, auctioned with cams which are part, in their
turn, from a sprocket wheel rack mechanism[2].
Figure 3. Crimping device with 12 tightening bacs.
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In figure 3 it is presented the crimping device having the following component: 1- fixing
block; 2 – cogged sector with 12 internal cams; 3 – crimping bacs; 4 – return resorts; 5 – cog;
6 – double rack; 7 – basic plate. The author has designed this device to work singular in
vertical position (figure 4) through the agency of a sprocket wheel mechanism or in tandem
with other device with cams, both auctioned by a sprocket wheel – rack mechanism, with
symmetrical profile.
In the second case, the devices have been assembled in horizontal position on the table
of a hydraulic press of 3 tf, (figure 5). On the skull of the press has been assembled the rack,
and in its lower part has been assembled a course limiter so that crimping can be done at a
minimum diameter of 3.8 mm. Behind each crimping device has been assembled a detent
chamber for eventual detonations that might be produced during the tightening process.
The crimping device from figure 3, functions this way:
At the displacement of the press‘s skull, the rack involving the cogged sector with internal
cams, displaces radial the 12 bacs to the tightening centre. The 4 claws of each bac deform
plastically the tube of the detonator, diminishing its diameter and at the same time realizing its
tightening over the obturator cork, being obtained the ensemble from figure 1. At the reverse
course of the rack, bacs are displaced reversely to resort 4.
Figure 4. Singular device.
Figure 5. Tandem of two dispositive.
4. Result of the experiments
In order to show the efficiency of using this device, we have initiated two types of
experiments [5]:
- efficiency of the crimp for the alienation of the accidental explosion of the
detonator at dynamic removal ;
- efficiency of the crimp against the penetration of the water inside the detonator
and the compromising of the explosive load; at this test has been verified also if the
exaggerated tightening of the tanks did not lead to the perforation of the tube in this area, the
separation of the rheophores from the inflamator, the short-circuit or grounding of the
rheophores.
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The first type of experiments has been realized with the aid of stand from STAS
8136/1985, and the results of the experiments are presented in table 1.
The second type of experiments required according to STAS 8136/1985 norms, the
introduction of the detonators in a water recipient at the depth of one meter and the realization
of the electrical measurements followed by detonations after being maintained at this depth
for 24 hours.
The result of the experiments are presented in table 2.
6. Conclusions
The analyse of the results lead to the following conclusions[1]:
- By modifying the penetration depth of the crimping bacs, from a maximum value
of Ø 4.2 mm to a minimum values of Ø 6.6 mm, it can be observed an accentuated increase of
the rheophores displacement from the obturator cork, followed in some cases by explosions;
- Concerning the variant with 3 ribles (rings) of crimping, no removal of the
rheophores with diameter of 4.2 mm is realized, meanwhile at the variant with 4crimping
circles, these can not be produced starting with the diameter of 4.6 mm;
- The crimping with 4 crimping ribles presents the best safety against water
penetration inside the detonator, starting with a diameter of 4.2 mm;
- Mechanised crimping represents a safe solution for the removal of the un-uniform
crimping of the detonators, followed by explosions at manipulation or flegmatization of the
explosives in composition;
- Using cams in operating the tanks- pegs constitutes a reliable solution in building
tightening mechanisms with several fingers.
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Bibliography
1. Popescu Gh; Ghimiş Ştefan; Stancioiu Alin. The results of the researches reguarding the
use of cams mechanisms in assembling electrical detonators. Annals of the Oradea
University- Fascicle of Management and Technological Engineering, Volume VII
(XVII),2008, Editura Universităţii din Oradea, pag. 1040.
2. Popescu Gh. Cercetări experimentale pentru realizarea unui dispozitiv de sertisare
detonatori electrici. Proceedings scientific conference 9-th edition with international
participation – „Constantin Brâncuşi‖ University of Târgu Jiu, 2004, pagina 81.
3. Popescu Gh. - Implicaţiile dopului opturator injectat asupra siguranţei detonatorilor.
Analele Universităţii ‖C-tin. Brâncuşi‖Târgu Jiu – nr. 1, seria A, 1994.
4. Leţu Nic. Popescu Gh. - Posibilităţi de înlăturare a exploziilor necomandate, provocate
de smulgerea reoforilor la capsele detonante electrice. Revista ‖ Mine, Petrol, Gaze‖, vol
33, Bucureşti, 1982.
5. * * * STAS 8136/1985.
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DYNAMIC ANALYSIS OF A CRIMPING DEVICE WITH
MULTIPLE CAMS USING MSC ADAMS
Part II.Shaping of the tightening forces from a crimping device with
multiple cams, using MSC ADAMS
Prof. Univ. Dr. Eng. Gheorghe Popescu,
University ―Constantin Brâncuşi‖ of Târgu Jiu
e-mail: [email protected]
Abstract:Through the present paper, the author presents the results of the dynamic analysis with MSC
ADAMS of the mechanism with a crimping device with 12 tightening cams, designed and used in the
technological process of assembly of the indigenous electrical detonators. In this sense, the mechanism with
multiple cams is considered a mechanical system and is treated as an assembly of rigid bodies connected by
mechanical connections and elastic elements.
For shaping and simulation of the mechanism with multiple cams using ADAMS program, the author got
through the following stages: construction of the pattern, its testing and simulation, validation, finishing,
parametrization, optimization of the pattern.
Key words: Shaping, simulation, parts, connection, spring, operation engine, parameterization, optimization.
1. Introduction
For shaping the tightening forces, we have started from the hypothesis that in the
process of design and use of the crimping device with multiple cams, the greatest part of the
energy receives has been used to realize the crimping operation [1].
It is obvious that the mechanical efficiency of this device depends on the type of the
resistances appearing during its functioning, on the working conditions, on the construction of
the elements and the cinematic couples of the component mechanism, on the lubrication and
maintenance modality of the mechanism, etc. That is why, for the mechanism of the crimping
device it is not possible the specific determination of the values for the mechanical
efficiency[2]. To realize an energetic study and calculation of the mechanical efficiency it is
necessary a theoretical and experimental analyze.
In the stage of theoretical analysis, our study consisted in realizing a dynamic analyze
based on which has been established the mathematical pattern and the auctioning force on
each crimping tank.
Alongside experimental stage, the study has been focused on the determination of
some dynamic parameters in mechanism, using the package of programs MSC ADAMS.
2. Structural shaping of the multiple cams crimping mechanism through the soft
ADAMS
The crimping mechanism with multiple cams is considered a mechanical system and is
treated in ADAMS as an ensemble of rigid bodies (named parts), connected through
mechanical connections (named couples) and elastic elements [3].
The stages for shaping and simulation of the multiple cams crimping mechanism with
program ADAMS are presented in scheme in the figure 1.
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The types of pasts included in ADAMS are: rigid bodies, elastic bodies and bodies
without mass. Rigid bodies are defined by mass and inertial properties.
ADAMS contains a library of elementary solids (sphere, cylinder, torus and so on),
from which can be created complex bodies (solid composites) by the application of Boolean
operation (reunion, extraction, intersection). Rigid bodies can be created also starting from
closed plan surfaces by adding the thickness (extrusion), namely by rotation around a central
axis (rotation surface).
On the bodies from the mechanical system of the mechanism with multiple cans can
be imposed the initial conditions of positioning – orientation, that are taken into consideration
in its assembly process [5,6].
This process, named also the analysis of the initial conditions, is very useful in case it
is not recognized completely the shaping functional configuration (in the initial position) of
the mechanism.
Figure 1. Stages for shaping and simulation of the crimping mechanism with multiple cams,
with the program ADAMS.
The mechanism with multiple cams in figure 3 consists of 12 identical mechanisms.
For shaping and simulation of the crimping mechanism with multiple cams, with the ADAMS
program it is sufficient to study on mechanism presented in figure 2.
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For this, are known the geometrical dimensions of the crimping tank (PART_8),
configuration of the cam (PART_7), location of the spring for maintaining the contact cam –
tank (SPRING_1.sforce), locations of the couples on the elements of the mechanism
(JOINT_1, JOINT_2, JOINT_3), as well as the ensemble configuration of the mechanism
(model_1), in other words the global coordinates of the point where positioned the couple of
the cam rotation.
Figure 2. The pattern executed in ADAMS.
Shaping based on MSC ADAMS soft has as basis the principles of solid shaping [7];
in this sense, are determined automatically the mass, the inertial tightener and the position of
the mass centre of the shaped elements. The couples of the mechanism have been
implemented, using the library of couples of the soft, by indicating the connection between
different component elements of the pattern realized or from the elements and the fix part on
base type (PART_9).
Figure 3. Connexions between different elements of the pattern, external attempts and the engine.
Figure 4. Graphic of the rotation angle of the cam.
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Figure 5. Graphic of tank’s displacement.
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Figure 6. Graphic of the contact forces on axles x
and y.
Figure 7. Graphic of displacement of the radial force
for the deformation of the tube.
In the following stage, has been shaped the engine (MOTION_1) and has been applied
the external resistant technological force, auctioning on the mechanism with cams (in the
present case, the radial force of tube‘s deformation - SFORCE_2, applied on the tightening
tank). The connections between different elements of the pattern, external tests and the engine
are presented succinct in figure 3.
Figure 8. Graphic of energy consumption.
Figure 9. Graphic of engine torsion moment, applied
to the shaft of the cam.
Figure 10. Graphic of deformation of the spring.
Figure 11. Graphic of the resort force.
The signification of the elements from figure 3 is presented as follows: Ground
represents the fix element (basis); PART_A - element A; Revoulte Joint - rotation couple;
Single_Component_Force - unique component of the force; Contact - contact; Translational
Joint - translation couple; Fixed Joint - fix couple; Rotational Motion - rotation engine.
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The entrance parameters used for the realization of the simulation are: rotation angle
of the cam - seen graphically in figure 4; displacement of the tank - seen graphically in figure
5; contact forces on axes x and y - seen graphically in figure 6; displacement of the radial
force for the deformation of the tube - seen graphically in figure 7; consumption of energy seen graphically in figure 8; moment of engine torsion, applied to the shaft of the cam - seen
graphically in figure 9; deformation of the spring - seen graphically in figure 10; force of the
spring - seen graphically in figure 11;
Taking into account the character of the variation for entrance parameters (presented
in upper figures) are imposed the following observations:
- angle speed of the entrance shaft is constant;
-has been considered a linear variation, in time, of the rotation angle, so that this has
the value of 0o at the end of the simulation and the maximum values of 11o at the end of the
time interval that is necessary for simulation;
- the value of the displacement speed of the peg has been elected depending on the
shape of the cam, to illustrate more convenient the character of the forces on contact1;
- the movement law of the profile of the cam has been realized with 2 bearing: easily
increasing, and increasing, depending on time.
Before beginning the simulation, has been realized the verification of the created
pattern. By verification, the soft presented automatically the results presented in figure 12.
From the ones presented above, can be considered the following:
- the pattern contains 2 elements in movement;
- there are 2 couples of class V, one of rotation and one of translation (namely 2x5
constraints);
- there is 1superior couple of class IV (1x4 constraints);
- the pattern has one independent movement (rotation realized by the entrance shaft);
- the pattern has one degree of mobility;
- there are no redundant constraints, the pattern being verified successfully.
Taking into account the results of the pattern verification stage (results certifying the
fact that the pattern has been correctly realized) as follows will be realised the simulation of
the dynamic behavior of the realized pattern.
For simulation has been considered a time interval of 0.36 seconds.
Figure 12. Verification of the created pattern.
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3. Simulation results
By simulation of the realized pattern, have been observed: the determination of the
displacement distances of the tightening tank; observing the displacement law of the tank;
determination of the variation of the forces on contact 1; determination of the variation of the
energy consumption at the displacement of the tank.
As results from figure 8, the displacement of the tank n a rotation cycle of the cam
o
(11 ) is of 1,35 mm; even if the displacement speed of the tank is uniform, when the cam
rotated with 4,5 o, for a duration of 0.02 s, the displacement of the peg stops returning to
position of 0 mm, after that the displacement is uniform until the end of the cycle. The
explanation is given by the beam of connection between the profiles of the cam, not correlated
with the contact area of the tank. It has been observed that the contact forces in that area, as
well as the moment of torsion of the cam‘s axle are minimal.
The figure 9 shows that there is an active component of the contact force on the
direction of the Ox axis and an inactive component with very small values on the Oy axis.
The active contact force has a linear variation and is maximum at the end of the work cycle.
4. Conclusions
As a result of interpretation the result of the simulation, can be formulated the
following conclusions:
1. The displacement of the tightening tank in a cinematic cycle is of 1.35 mm,
sufficient to realize a quality peg;
2. 80% from the value of the contact force is transmitted on the direction of the Ox
axis and 20% on the direction of the Oy axis;
3. The mechanical efficiency of the crimping mechanism with multiple cams depends
to the greatest extent on the active component of the contact force;
4. Advanced usage of the peg on the action direction of the active force or the
apparition of the usage points to the area of end of the cycle for the profile of the cam,
determines insufficient displacement of the peg as well as internal contact forces for the
deformation of the tube, submitted to the crimping operation.
Bibliography
1. Popescu Gh; Ghimiş Ştefan; Stancioiu Alin. The results of the researches reguarding the
use of cams mechanisms in assembling electrical detonators. Annals of the Oradea
University- Fascicle of Management and Technological Engineering, Volume VII
(XVII),2008, Editura Universităţii din Oradea, pag. 1040.
2. Popescu Gh. Cercetări experimentale pentru realizarea unui dispozitiv de sertisare
detonatori electrici. Proceedings scientific conference 9-th edition with international
participation – „Constantin Brâncuşi‖ University of Târgu Jiu, 2004, pagina 81.
3. Jula, A. Multibody modeling of the tripod coupling. Proceedings of Research and
Development in Mechanical Industry – RaDMI 2002, vol.2, VrnjaOka Banja, Yugoslavia, 1 –
4 september 2002. p. 649 – 654.
4. Alexandru, C. Testing the Guiding - Suspension System of the Motor Vehicles in Virtual
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Environment. International Review of Mechanical Engineering, Vol. 3 (5), 2009, p. 521-528.
5. Alexandru, C. Virtual prototyping of mechanical systems used to the renewable energy
sources. Proceedings of the First Conference on Sustainable Energy – CSE, Bra_ov, pag. 69
(Abstract Book), 2005.
6. Bernard, A. Virtual Engineering: Methods and Tools. Proceedings of the Institution of
Mechanical Engineers, Part B: Journal of Engineering Manufacture, Vol. 219 (5), 2005, p.
413-421.
7. *** Getting Started using ADAMS v2011, MSC Software, 2011.
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THEORETICAL RESEARCH ON THERMAL MODELING OF A HIGH
POWER AUDIO DEVICE
Prof.Univ.ing. Dr.Constantin D.Stanescu- Universitatea ―Politehnica‖ Bucuresti
e_mail : [email protected]
Prof. ing.drd.Liliana Cainiceanu –Universitatea ―Politehnica‖ Bucuresti
e_mail : [email protected]
Prof.drd.Tudor Burlan- Universitatea ―Politehnica‖ Bucureşti
e-mail:[email protected] yahoo.com
ABSTRACT :This paper aims at analyzing the mechanism of heat transfer and consequently a thermal
analysis. Data obtained provides a starting point in choosing solutions constructrive, mechanical and electrichal
dynamic audio device prototype .A comprehensive approach allows optimization of device based on our
maximum eficianta developed model and finite element analysis program using coupling possibilities in different
conditions.
Keywords: magnet, speaker, transducer
1.INTRODUCTION
Most speakers today are products of "electrodynamic" or "permanent dynamic." Schematic
representation of such a speaker is shown in Figure 1
Fig. 1.Schematically representation of a permanent dynamic audio device :1-coil support, 2-coil, three-board
back, 4-permanent magnet, front plate 5, 6-cone membrane, 7-membrane suspension, 8-capacde dust; 9-chassis
(frame), 10-centering membrane
The speaker is basically a transformer (transducer) of electrical energy in the acoustic
energy passing through mecanica.Numai a small amount of energy used is converted into
acoustic energy, the rest being lost in part by the heating effect of electric current, partly by
eddy currents and partly by friction in mechanical system. The audio device applications is
that a circuit with concentrated parameters as in Fig.2
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Fig.2. Equivalent circuit with concentrated parameters of the speaker transducer
Where : U is the the voltage supply control for audio device ; Re is the electric resistence ;
Le is the inductance of mobile coil ; Rms – equivalent resistence of the losses of the mobile
sistem ;Cms – equivalent capacitance losses ; Zmr – acoustic radiation impedance of the
vibrating piston corresponds to one side of the membrane
The transducer is represented as a transformer with transformation ratio B∙ l :1 from
electrical to the mechanical ,where B is the magnetic induction and l is the length of the
conductor coil. It can make a formal equivalence between the electric and the acoustic , the
mechanical force and speed is corresponding to voltage and current. This equivalent circuit
can be used both in electrical engineering and in the sound, depending on the intended
purpose. The electrical circuit can be used to determine the frequency behavior of the speaker
(resonance frequency) and the mechanical (acoustic) can be used to determine the total
radiated power or sound pressure.
Total radiated power is the power dissipated in the environment acoustic radiator.
Based on Figure .2, radiated power is 2∙Rmr ∙ ν2 ,with Rmr, the radiation resistance.
There are two requirements for the new speaker:
1.) Mobile equipment to suport the developed high power
2.) Acoustic efficiency of the speaker to be high.
Thermal analysis seeks to define the limits of power for the prototype to be built.
Electric power is applied to the mobile coil. Terem dissipation is concentrated in the narrow
air gap of magnetic circuit .Adhesives used to fix the coil support on the membrane, and the
permanent magnet ,wire insulation are the most susceptible to overheating.
2.. MODELING THERMAL DEVICE AUDIO
Electrical energy is transmitted to mobile coil. Most energy is used for heating coil,
some energy is transformed into mechanical energy, of which a fraction is converted into
acoustic energy. If energy transfer by radiation is neglected, energy transfer coil surrounding
air that circulate through the air gap. Thermal energy is then transmitted to bodies in contact
with hot air, bodies found in the region of flow, thus warm the magnet and pole piece.
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COIL
UNIT
POLE PIECE
MAGNET
CHASSIS
AIR (INSIDE)
Fig.3.Simplified cooling model of speaker
It uses concentrated parameters model in figure 2.
Heating speaker is due to the resistors of the scheme. Losses due to friction in the
system is neglected . Heat is generated in the coil which transmits the ambient air. A coil
support with high thermal conductivity can prevent rising hot spots in windings and removes
heat from the air gap. Airflow partially transmits heat to the permanent magnet pole piece and
the channel forming flow. Hence heat is removed by convection or radiation to the
environment.Based on the simplified thermal model described above ,the thermal equivalent
circuit (for stationary thermal regime) is presented in figure 4 .
Fig.4. Simplified thermal modelul of speaker.
The concentrated parameters model from figure 2, determine the heat resistance of the
speaker schedule. A major contribution to heating has Rms. Losses due to friction in the
system and the air surrounding the coil are neglected .The heat is generated and transmitted to
ambient air.
A coil support with high thermal conductivity can help to avoid the ' hot spots' in the
windings and helps remove heat from the air gap.
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Fig.5. The air flow circulating in the air gap (a) classical, (b) leg "ventilated"
For low frequencies, the high-powered, some manufacturers made a pole piece
ventilation channel, see fig. 5 (b) as a supplementary heat in the exhaust. But this solution
reduces air velocity in the coil, the air gap, so be well analyzed before being applied
Analysis using finite element modeling can complement optimizing constructive solution.
There are some problems in modeling finite element diffuser structure, most problems
resulting from the cooling the air gap mechanism .
Computational Fluid Dynamics, (CFD) require a finer mesh in areas with high gradient of
temperature and usually require more memory and computing time. CFD analysis result will
be presented as temperature, air velocity and temperature of solid zones .
Boundary conditions are imposed in the area of fluid flow. Solid surface areas, usually
normal speeds are zero and the domain boundaries are prescribed zero speed or require
temperatures known. Effects due to natural convection (buoyancy) can be taken into account
by specifying a value of gravitational acceleration (g = 9.8 m/s2)
Moving areas will be modeled with a relative velocity of the fluid turbulence inducing
factor in the equation. In determining whether flow should be estimated Reynolds number:
Re = (ν ∙ ρ ∙ L) / μ
(1)
with ν air velocity, air density ρ, length L characteristic and dynamic viscosity μ.
For an estimated average amplitude A = 5 mm ,the relative speed for harmonic
oscillation frequency of 100 Hz is 2 ∙ π ∙ f ∙ A = 3.14m / s, which corresponds to the actual
2.22 m / s
If you consider the flow channel width of 2 mm (the value of L in this case is 4 mm)
and for proper air ρ = 1006 kg/m3, μ = 1.873 ∙ 10-5Kg / m ∙ s get a Reynolds number of 240.
The critical Re number is about 2200. In this case, the result indicates a laminar flow.
The turbulent flow will turn algorithm for moving areas.
CONCLUTIONS
Computational Fluid Dynamics, (CFD) require a finer mesh in areas with high
gradient of temperature and usually require more memory and computing time. CFD analysis
result will be presented as temperature, air velocity and temperature of solid zones .
Boundary conditions are imposed in the area of fluid flow. Solid surface areas, usually
normal speeds are zero and the domain boundaries are prescribed zero speed or require
temperatures known. Effects due to natural convection (buoyancy) can be taken into account
by specifying a value of gravitational acceleration (g = 9.8 m/s2)
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REFERENCES
[1] Otto J. , ―Dynamic Simulation of Electromechanical System using ANSYS and
CASPOC‖ ANSYS Conference ,22-24 April 2006 ,Pittsburg, USA.
[2] Rohsenow W.M., Hernett J.P. ,Young I., ―Handbook of transfer‖ -3th edition ,
McGraw-Hill ,1998
[3] Dodd M. , ―The Application of FEM to the analysis of Loudspeaker Motor Thermal
behavior‖ ,The 112th Convention of Audio Engineering Society ,2002 May 10-13,
Munich,Germany.
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EXPERIMENTAL THERMAL SIMULATION OF THE HIGH AUDIO
SPEAKER
Prof. ing.drd.Liliana Cainiceanu –Universitatea ―Politehnica‖ Bucuresti
e_mail : [email protected]
Prof.Univ.ing. Dr.Constantin D.Stanescu- Universitatea ―Politehnica‖ Bucuresti
e_mail : [email protected]
Prof.drd.Tudor Burlan- Universitatea ―Politehnica‖ Bucureşti
e-mail:[email protected] yahoo.com
ABSTRACT:This paper uses a thermal simulation model that can be applied to electromagnetic field and for the
sound. Due to the symmetrical structure difuzorlui using AXI-symmetric pattern which significantly reduces
computing time.
Key words :magnets, air gap, coil
1.INTRODUCTION
To reduce the number of elements we consider membrane for thermal analysis, a little thicker
than the real one. Construction details of the frame (chassis) will also be simplified,
preferably using straight line model.
Model with main geometrical parameters is shown in Figure 1, and values are given in Tab.1
Fig1.The speaker used in the simulation represented with the main parameters (ambient air is presented in full)
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Parameters
(mm)
P100
P200
P300
Table 1. Geometric parameters of the model speaker
RC
HC
RPI RPE HM
HP
RF
40
85
125
20
30
50
9
17
25
27,5
43,5
60
10
15
20
16
27
32
50
100
150
In the mesh, special attention was paid to interior cavity where there is most
important, namely the heat transfer coil. In the air gap were used rectangular elements. The
discretized (with mesh) is shown in Figure 2 (a)
Fig.2 (a) The discretized., (B) 3D model made by extension symmetry due
2.MATERIALS
Material parameters used in the analysis are presented in Tab.2
Tab.2. Material properties used in analysis
Mat.nr.
95
Materials
Thermal
conductivity
(W/ m ∙K)
3,2
Density
(Kg / m3 )
Specific heat
(J/ Kg∙ K)
4400
750
1
Ferrite (magnet)
2
3
Soft steel (pole piece)
Paper (membrane)
48
0,18
7840
900
450
1340
4
5
Copper (coil)
Aluminum (support coil)
380
180
8920
2600
385
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ANSYS has been used in the simulation, request that the material always be No.1 air
(or fluid) and taking into account mecanisumul natural convection (buoyancy) physical
properties of air to be highlighted in particular are temperature and density.
Area that extends to the air must be large enough not to influence the flow of heat in
the area of interest, but bear in mind the overall size of the model.
Analysis performed using conjugate heat transfer process. Both areas of fluid and
solids are modeled together using the same type of finite element.
CFD analysis (Computational Fluid Dynamics) performs calculations necessary to
satisfy the law of conservation of momentum and mass. This analysis is (fluid flow) suitable
for problems involving convection cooling. The disadvantage of this method is that for
materials with thermal conductivities is different the precision is not good. Analysis was
performed with a transient simulation for high enough temperature to obtain the stationary
solution.
Analysis of steady state model is applied using the initially solutiones. Coil was
modeled with constant power density proportional electric power applied to the speaker.
3. RESULTS OF MEASUREMENTS AND SIMULATION
Simulations and measurements were made assuming that we have two types of speakers that
we call "small", P100 and that "high", P200 frames with outer diameters of 100 mm and 200
mm respectively. Figure 3 shows the speaker P100.
Fig.3 .P100 speaker with diameter 100 mm (a) front view (b) rear view
Speakers analyzed power ratings of 20 and 100 W. The measurements were made
using about 100 Hz sinusoidal signal.
For temperature measurements were used based on contact measurements based on an
acquisition system with thermocouple on one side and additional measurement system based
on IR (infrared). We used a total of five thermocouples placed in different positions, including
positions "hidden" for IR measurements.
Speaker P100 was prepared in two versions with a coil made in support of a classic paper and
support alumniu.Masuratorile and simulations were conducted at a power level of 16W for
small speaker, 50 W respectively the largest.
Measurement results are presented based thermocouples in tabele3, 4 and 5
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Table 3. Measurement results on loudspeaker of 10 cm coil support the paper.
Frequency
(Hz)
Power
(W)
Tmax(IR)
(°C)
1
100
1000
100
1000
100
1000
8
8
16
16
20
20
39
63,8
74
86,1
88,6
92,5
34,3
52,8
54
70,4
68,8
75,8
Temp.termocuple(°C)
2
3
4
32,5
50,3
50,9
66,5
65,1
71,4
30,2
47,1
45,7
61,1
58,7
65,4
27,5
43,7
35,6
55,8
41,7
59.4
5
23,9
34,2
25,6
40,2
26,9
41,4
Area
graph
from
fig.6.
A
B
C
D
E
F
Table.4. Measurement results on loudspeaker of 10 cm aluminum coil support.
Frequency
(Hz)
100
1000
100
1000
Power
(W)
8
8
16
16
Tmax Infrared (°C)
Front Profile Back
38,8
79,8
58,3
109
29,6
43,1
39,8
53,5
39,5
42,8
43,0
57,6
1
30,7
47
43,7
63,6
Temp.termocuple(°C)
2
3
4
30
44,9
42,2
60,1
27
39,6
34,4
51,9
26,8
40,3
33
52,2
5
24,2
32,2
26,3
38,6
For data interpretation is necessary to specify the position thermocouples attached
speaker. For Tables 3 and 4 position thermocouples was 1-5 in Figure 5:
Figure 5 Position thermocouples the measurements contained in Table 3 and 4, Bolt central flange 2
inf. Magnet 3, 4 cavity lateral to the coil, 5 Chassis
Speaker P 200 with a diameter of 20 cm have been used only four thermocouples,
thermocouples denoted by 1,2,3 and 4 in Table 5 are the positions in Figure 5, respectively as
follows: 4 cavity, 2 flange. 3, magnet, 5 chassis.
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Tab.5 Results of measurements for speaker on 20 cm with aluminum coil support
Frequency
(Hz)
100
1000
100
1000
Power
(W)
20
20
50
50
Tmax Infrared (°C)
Front Profile Back
63,7
54,3
76
101
44,5
37,6
43,2
56,1
39,3
40,6
47,9
60,3
Temp.termocuple(°C)
1
2
3
4
35,1
37,5
43,2
52,1
37,7
39,6
47,3
60,8
32,6
36,2
41
47,8
25,5
28,0
30,1
28
Mains based on data acquisition can be represented graphically and time evolution of
temperature in the 5 samples that were placed in temperature. For configuration presents
search The results for configuration presents in Table 3 is shown in Figure 6
Fig.6.Evolution of temperature measurement in the 5 point of measurement corresponding from Table 3.
The data in Figure 6 have estimated thermal time constant of the speaker, a value that
was useful for transient simulations the choice of the final simulation time.
CONCLUSIONES
Was performed thermal modeling and simulation of a permanent dynamic speaker on
finite element analysis that uses fluid flow (CFD analysis) .
Simulation results were accompanied by complex measurements.
For the purposes at this stage of research the results of measurements corespond with the
simulation results.
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REFERENCES
[1] Otto J. , ―Dynamic Simulation of Electromechanical System using ANSYS and
CASPOC‖ ANSYS Conference ,22-24 April 2006 ,Pittsburg, USA.
[2] Rohsenow W.M., Hernett J.P. ,Young I., ―Handbook of transfer‖ -3th edition ,
McGraw-Hill ,1998
[3] Dodd M. , ―The Application of FEM to the analysis of Loudspeaker Motor Thermal
behavior‖ ,The 112th Convention of Audio Engineering Society ,2002 May 10-13,
Munich,Germany.
99
Fiabilitate si Durabilitate - Fiability & Durability Supplement no 1/ 2012
Editura “Academica Brâncuşi” , Târgu Jiu, ISSN 1844 – 640X
A GENERALIZED INTEGRAL-GEOMETRICAL THEORY IN MINING
SUBSIDENCE
PART I
Ph.D. Michail VULKOV, University of Mining and Geology ―St. Ivan Rilski‖, Sofia,
Bulgaria, [email protected]
Abstract. A new mechanical and mathematical model for mining through formation is suggested. A vector
function which describes the created displacement possibility of the influence zone points of the mining
excavation is applied. The points put under influence react specifically to the offered displacement possibility.
The reaction functional describes their behavior. The cause-effect connection between the behavior of the
displacement’s sources and the reaction of the influence area points is described. The vector function of the
source of displacement is obtained. The required simplification for mining out a coal seam is made. A new
formula for determining the vertical displacement field is obtained.
An approach is suggested which makes it possible to determine the reaction of the rock mass on basis of in-situ
measurements. The reaction of the rock mass of the created displacements possibility is determined analytically
after measurements of the displacements in a given mining field are performed. This allows better calculation
results to be obtained and offers an opportunity to adapt the calculated procedure to the unique conditions in a
specific mining field.
Key words: mining geomechanics, mining subsidence, influence function, reaction function
1. Introducing the Idea
The search of formulae describing the process of the rock mass subsidence above a field of
underground exploitation has been initiated by mining damages.
The phenomenon discussed in this paper is the occurrence of depression on the earth's surface
above a field of underground exploitation. If by underground mining a part of geomaterial is
removed, then the particles above the mined-out area will move downwards until arranging a
new equilibrium state (Fig.1)
By using an integral-geometrical theory for predicting the mining subsidence the
following formula is applied [3]:
w  x, y  
   x   , y    w  ,  d . d , (1)
F 
where   x, y  is the influence function;
w  ,  is the subsidence of the collapse area borders.
In order to describe the displacements caused by mining the following mechano-mathematical
model is suggested [4]:
Let us assume that the rock mass points belong to two multitudes. The mining-out
geomaterial points Q .
These points are treated as infinitesimal source of displacement possibility.
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
Their behaviour can be described by a vector-function q  Q  defined in area  Fig.2.
Fig. 1. Scheme for subsidence calculating after
integral-geometrical theories
Fig. 2. Influence and reaction in rock mass

Let us assume that q  Q  can be written as follows:




q  Q   qx  Q  i  q y  Q  j  qz  Q  k ,
Q  (2)
  
where i , j , k are the single vectors of the chosen coordinate system.
When a point Q  is removed a displacement possibility is created for all points Pi   of
all strata between the extraction level and the surface. These points Pi belong to the second
multitude  , which members are put under the influence of the infinitesimal sources. The
displacement of the points Pi   can be written as:




V  Pi   Vx  Pi  i  Vy  Pi  j  Vz  Pi  k ,
Pi   . (3)
The point put under influence reacts specifically to the given displacement possibility.
Its behavior may be described by the reaction‘s functional:
Wxx Wxy Wxz
W  Pi   Wyx W yy W yz ,
Pi   . (4)
Wzx Wzy Wzz
The cause-effect connection between the behavior of the sources and the reaction in the
influence area is described by the operator F:
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



V  Pi   F  Pi , Q,W  Pi  , q  Q   , Pi   , Q  . (5)


It is supposed the operator F is a linear one [6], i.e:




F  Pi , Q1, Q2 ,W  Pi  , q  Q1   q  Q2   


(6)






 F  Pi , Q1,W  Pi  , q  Q1    F  Pi , Q2 ,W  Pi  , q  Q2  .




In order to calculate the displacements of all points Pi   caused by extraction of all points
Q  , let us ascribe the operator F an integral character:


V  Pi    W  Pi  q  Q  dx dy dz

Pi   , Q  (7)
or
Wxx Wxy Wxz qx  Q 
Vx  Pi 
V y  Pi    Wyx Wyy Wyz q y  Q  dxdydz . (8)
Vz  Pi 

Wzx Wzy Wzz qz  Q 
The process described by (8) can be viewed upon as a filtration through the rock mass of the
displacement possibility provided by the mining out of geomaterial. According to the

superposition principle the total displacement V  Pi  of the point Pi , is understood as the

integral of the partial causes q  Q  , filtrated through the functional W  Pi  .The latter
represents the rock mass reaction to the provided displacement possibility.
Thus, all the infinitesimal sources Q  create displacement possibility in every point Pi  
in the influence area. The provided displacement possibility is an integral characteristic of the
action in a point Pi   of all the sources Q  .
The possibility mentioned above does not depend on the Pi points in any way.
The reaction of the rock mass points Pi   is a local characteristics. It gives expression of the
degree in which the potential displacement possibility will be realized. In fact this
characteristic transforms the abstract medium into a real physical object, which has been
ascribed elastic, plastic, reological etc. properties.
2. Simplifying the Model by Coal Mining
The model can be simplified by the conditions of coal mining as follows [5]:
- It may be viewed a plane problem;
- It may be assumed that the displacement of Pi   caused by the infinitesimal source Q 
is directed from Pi to Q ;
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- According to the fact that H> >m (Fig3.), it may be assumed that the sources lying one over
the other have the same influence to the rock mass points.
Fig.3. Subsidence by mining out a horizontal coal seam - plane problem

Let us draw our attention to the coal seam shown in Fig.3. In this case the function q  Q  ,
describing the infinitesimal source behaviour can be written as follows:



q  Q   qx  Q  i  q y  Q  j ,
Q  . (9)
The displacement of the point Pi   can be introduced as



V  Pi   Vx  Pi  i  Vy  Pi  j ,
Pi   . (10)
The functional describing the rock mass reaction is expressed by:
W  Pi  
Wxx Wxy
Wyx Wyy
,
Pi   . (11)
Thus, for the components of the displacement vector is fulfilled:
Vx  Pi    Wxx qx  Q   Wyx q y  Q   dxdy

Pi  , Q  (12)
Vy  Pi    Wxy qx  Q   Wyy q y  Q   dxdy .

The nuclei of the integrals (12) express the reaction of a rock mass point Pi   on the
provided displacement possibility by a infinitesimal source Q  by viewing a plane
problem.
3. The New Formula
The attempts to present the changes in the geomechanic setting only through the influence
function without impacting the structure of the relation itself did not produce any encouraging
results [6].
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For calculating the displacement of a real medium we have to ascribe its physical and
mechanical properties, which determine the medium reaction to the provided displacement
possibility.
From equation (12) we get:
Vx  Pi   Wxx  qx  Q  dxdy  Wyx  q y  Q dxdy 


 Wxx Rx  Wyx R y  Vx1  Vx2 ;
V y  Pi   Wxy  qx  Q  dxdy  Wyy  q y  Q dxdy 

;
(13)

 Wxy Rx  Wyy R y  Vy1  Vy2 .
In these relations Vx2
is a horizontal displacement realized as a result of the vertical
behaviour of the infinitesimal source. Analogically, V y1 is a vertical displacement as a result
of the horizontal behaviour of the source [5].
Accounting the sense of the functions Wkt  k , t  x, y  as a local medium characteristic, which
determine how the displacement possibility is realized obviously, they will change into the
following limits:
0  Wkt  1
 k , t  x, y  .
The following changes are introduced to align the notations in the paper with the standard
ones found in the mining literature [3]:
By solving plane problems (8) may be written in the form:
u
 a.m
w
or
g xx g xy
g yx g yy
fx
(14)
fy

u  a.m g xx . f x  g xy f y



(15)
w  a.m g yx . f x  g yy f y ,

where f  x, y  is the influence vector function with components fx,fy ; gkt=Wkt (x,y=k,t) are the
components of the rock mass reaction tensor G  x, y  .
By determining the reaction's functional we have to specify the most important physical and
mechanical properties of the rock mass, which govern the displacement behaviour of this a
medium above a field of underground mining.
The main goal in mining subsidence predicting is the vertical displacement determining.
Let we assume in second equation of (15) that gyy >> gyx and fy >> fx .The observation in situ
verify this suggestion. The horizontal displacement is a function of the vertical one. It can be
calculated after Avershin [1].
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In this way from (15) we get for the vertical displacement the following new formula:
w  x, y   a.m. f  x .g  x  , (16)
where w(x,y) is the vertical displacement of a point Pi of the influence zone whit coordinates
(x,y); a is a subsidence factor ; m is the mined out thickness of the coal seam; f(x) is the
influence function ; g(x) is the rock mass reaction function.
Formula (16) is a generalization of the classical main formula for the subsidence calculation
w  x, y   amf  x  , (17)
where g(x) = 1, i.e. when all of the displacement possibility turns into subsidence.
Formula (17) represents the vertical displacement of a point Pi of an ideal medium, if it
exists.
To complete the study we have to specify the influence function and the rock mass reaction
function. This is realized in the second part of the paper.
References:
1) Авершин С.Г. Сдвижение горных пород при подземных разработках. М.,
Углетехиздат, 1947, 215 с.
2) Вълков М.В. Нова формула за определяне на предизвиканите от подземни минни
работи премествания в скалния масив и на земната повърхност. VІІа национална
маркшайдерска конференция с международно участие, 19’23 юни 2000, Златни пясъци,
стр. 177’183.
3) Kratzsch Η. Mining Subsidence Engineering. Berlin, Heidelberg, New York, SpringerVerlag, 1983, p. 5431983, p. 543.
4) Vulkov, M.V. About the potential of a new adaptive mechanical model in mechanics of
mining subsidence. Mine surviving support of the verge of 21 century, l0-14 June, 1997,
Nessebar, Bulgaria p. 229-239.
5) Walther G.U., Bauer E. Die Anwendung eines mathematischen Modells zur
Vorausberechnun von Bodenbewegungen im Saar-Revier. Mitt. Markscheidewesen.
6) Wieland R. Ein Verfahren zur Senkungsvorausberechnung über Abbau in flach gelagerten
Flotzen auch unter Berücksichtigung der Besonderheiten eines durchbauten Gebirgskörpers.
Dissertation, T.U. Aachen, 1984, S. 91.
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Editura “Academica Brâncuşi” , Târgu Jiu, ISSN 1844 – 640X
A GENERALIZED INTEGRAL-GEOMETRICAL THEORY IN MINING
SUBSIDENCE
PART II
Ph.D. Michail VULKOV, University of Mining and Geology ‖St. Ivan Rilski‖, Sofia,
Bulgaria, [email protected]
Abstract. A new mathematical model for mining through formation is suggested. A vector function which
describes the created displacement possibility of the influence zone points of the mining excavation is applied.
The points put under influence react specifically to the offered displacement possibility. The reaction functional
describes their behavior. The cause-effect connection between the behavior of the displacement’s sources and
the reaction of the influence area points is described. The vector function of the source of displacement is
obtained. The required simplification for mining out a coal seam is made. A new formula for determining the
vertical displacement field is obtained.
An approach is suggested which makes it possible to determine the rock mass reaction on basis of in-situ
measurements. The reaction of the rock mass of the created displacements possibility is determined analytically
after measurements of the displacements in a given mining field. This allows better calculation results to be
obtained and offers an opportunity to adapt the calculating procedure to the unique conditions in a specific
mining field.
Key words: mining geomechanics, mining subsidence, influence function, reaction function
In this study the ideas, suggested in part I of the paper are completed. The influence and the
reaction function for a specific mining field are calculated. The numbering of the paragraphs,
formulae and figures follows these in part I.
4. Specifying the Source Behaviour (The Influence Function)
By mining out an elementary area dA  dxdy from domain  a displacement possibility
potential in point Pi   will be created as follows [4] Fig.4:
Fig.4. Scheme for determining the influence function
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U  , y   km ln
1
 2  y2
, (18)
where k is a reducing coefficient.
The components of the elementary displacement possibility can be written in following form
[1, 3]:
U

U
y
; dRy 
; Pi   . (19)
dRx 
 km
 km
2
2
2

y
 y
  y2
If the coal is mined out in the limits b < x < b for the total vertical displacement possibility
is obtained:
R y  , H   kmH
b
d
b
 x   2  H 2

. (20)
Then after changing the variables the integration is realized.
Thus, the vertical component of the total displacement possibility, which is provided in a rock
mass point Pi   by removing of the geomaterial in all domain  , can be calculated as
follows:
xb
x b 

Ry  x, H   km  arctg
 arctg
 , (21)
H
H 

where Ry  x, H   f  x, H  of the point Pi   .
In conclusion we should note , that the displacement possibility, calculated above represents
the displacement of a point of an ideal medium if it exists.
5. Specifying the Rock Mass Reaction
In a real medium we have to ascribe its physical and mechanical properties by using g(x,H),
which determine the rock mass reaction to the provided subsidence possibility.
By comparing the theoretical model (16) to measurement results in situ we will use
Avershin‘s (1947) natural observation realized in Stekinsy region of the Podmoskovsky coal
basin. The technological characteristics in this case are as follows -Fig 5a:
- Dept of working H = 60 m;
- Half length of working b = 30 m;
- Thickness of seam mined m = 2 m;
- Maximum subsidence wmax = 1,3 m.
In the Avershin‘s monograph [1] can be found the measurement results and the calculations
based on the potential theory of the vertical displacements. We should note that the results
and the analysis of Avershin verify the mechanical model suggested above and confirm its
applied potentiality.
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Actually Avershin notes that the calculated after the potential theory subsidence is bigger than
the measured one. This observation is in agreement whit the assumption in the new model. In
the potential theory solutions of Avershin is calculated the displacement possibility created on
the earths surface by removal of the coal, i.e. g(x) = 1.We can have g(x) = 1 only in the case
of an ideal medium where 100% of the displacement possibility offered in a point Pi   can
be realized.
Let us pay attention to Fig.5, where a partial mined horizontal coal seam is shown.
a
b
Fig.5. Measured and calculated subsidence realized in Stekinsy region of the Podmoskovsky
basin
On the earth's surface over that working the measured by Aversin subsidence trough is formed
Fig.5a.
Let us suppose the function w  x  represents the calculated after the potential theory mining
subsidence. The calculated subsidence is drawn by a continuous line (Fig.5) and is assumed as
the displacement possibility.
The function w (x, H) establishes the measured values of the vertical displacement. This
function is drawn by short dashes (Fig.5) It is assumed that the measured in situ subsidence
values are the real ones and are defined by the relation (l8). So it could be written:
w  x, H   amf  x  ,
(22)
w  x, H   amf  x  g  x  .
The difference between these functions is:
w  x, H   maf  x   maf  x  g  x  . (23)
The graphic of this function is illustrated on Fig. 6.
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Fig.6. Values of Δw(x, H)
The values of Δw(x, H) are given in column 5 of table l.
From (22) can be obtained
g  x  1 
w  x, H 
1
maf  x, H 
w  x, H 
w  x, H 
. (24)
Obviously 0 < g(x,H) < 1.
The discrete values of g(x,H) are given numerical in column 7 of table 1 and shown graphical
in Fig.7.
In accordance to the numerical values of g(x, H) in table 1 for determining the rock mass
reaction function will be used as an exponential function interpolation:


y  x   c.exp kx 2 , (25)
where k = const > 0; c = const.
109
Table 1
№ xi m
w  xi  m w  xi  m
 w  xi   w  xi 
w  xi 
g  xi 
y  xi 
1
2
3
4
5
6
7
8
9
1
10
1
1,3
1,28
1,22
1,10
0,82
0,60
0,40
0,28
0,20
0,18
0,17
0,01
0,02
0,12
0,26
0,30
0,30
0,24
0,20
0,17
0,16
0,16
0,9923
0,9844
0,9017
0,7636
0,6342
0,5000
0,4000
0,2857
0,1500
0,0778
0,0588
0,9963
0,9683
0,8887
0,7704
0,6307
0,4878
0,3562
0,2457
0,1600
0,0988
0,0572
0
10
20
30
40
50
60
70
80
90
100
1,29
1,26
1,10
0,84
0,52
0,30
0,18
0,08
0,03
0,02
0,01
0,0077
0,0156
0,0983
0,2364
0,3658
0,5000
0,6000
0,7143
0,8500
0,9222
0,9412
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Writing (25) in the form:
ln y  ln c  kx 2 .
and substituting
z  ln y; A  ln c
is obtained
z  A  kx 2 . (26)
Using second range polynomial interpolation must be written
a0  a1x  a2 x 2  A  kx 2 , (27)
where а1=0.
The normal system of the polynomial regression after Dorn and McCacen [2] takes the form:
11
 11 
 11 
11a0    xi  a1    xi2  a2   yi
i 1
 i 1 
 i 1 
11
 11 
 11 2 
 11 3 
  xi  a0    xi  a1    xi  a2   xi yi (28)
i 1
 i 1 
 i 1 
 i 1 
11
11
11
11



2
3
4
2
  xi  a0    xi  a1    xi  a2   xi yi .
i 1
 i 1 
 i 1 
 i 1 
By solving this system is obtained
с = 0,9963 and k = 2,8571.104.
a
b
Fig.7. Graphics of g(x) and y(x) functions
So the interpolation function is


y  x   0,9963exp 2,8571.104 x 2 . (29)
110
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This function is shown in Fig.7b. It gives acceptable results by calculating. The obtained
Gauss's interpolation function makes it possible to suggest hypothesis about the physical
nature of the rock mass reaction in the influence area.
6. The Final Result
The form of the suggested new relation is:


xb
x b

4 2
w  x, H   m.a. f  x, H  .g  x, H   0,9963.m.a.k  arctg
 arctg
 .exp 2,8571.10 x (30)
H
H


Taking into account the fact that by x  0 w(0)  wmax the coefficient k is determined as
follows:
k
wmax
b
1,9926.m.arctg
H
(31)
Finally the new obtained formula is
w  x, H  
wmax .a
b
2arctg
H

xb
x b 

4 2
. arctg
 arctg
 .exp 2,8571.10 x
H
H


 (32)
The relation (32) is adapted to the conditions of the Stekinsy region of the Podmoskovsky
coal basin.
Follow the suggested algorithms one can obtain the better adapted relation for calculating the
subsidence for every specific coal basin.
7. Conclusion
The considerations presented above lead to a new mechano-mathematical model for
describing the rock mass displacements caused by underground excavation of geomaterial.
The essence of such a model is its adaptation possibility for the specific conditions in a
specific mining field.
The new formula allows separate determining of the influence and of the reaction functions
connected whit the medium behaviour properties.
References:
1) Авершин С.Г. Сдвижение горных пород при подземных разработках. М.,
Углетехиздат, 1947, 215 с.
2) Дорн У.С., Макракен Д.Д. Числени методи и програмиране на Фортран-IV. С,
Наука и изкуство, 1977, 451 с.
3) Dimova V. Direct and Inverse Problems and Land Subsidence Mechanics. UMG,
University Press, 1997.
4) Vulkov, M.V. About the potentiality of a new adaptive mechanical model in mechanics of
mining subsidence. Mine surviving support of the verge of 21 century, June, l0-14, 1997,
Nessebar, Bulgaria, p. 229-239.
111
Fiabilitate si Durabilitate - Fiability & Durability Supplement no 1/ 2012
Editura “Academica Brâncuşi” , Târgu Jiu, ISSN 1844 – 640X
CALCULUL CINETOSTATIC AL MECANISMELOR
PLANETARE CILINDRICE
Ovidiu ANTONESCU, Păun ANTONESCU
Universitatea POLITEHNICA din Bucureşti
Abstract: În lucrare se prezintă o metodă analitică pentru calculul cinetostatic al mecanismului planetar
monomobil cu două roţi dinţate centrale. Se consideră mai întâi cazul general al schemelor cinematice cu două
roţi dinţate solidare tip satelit, în două variante practice (multiplicator şi reductor de turaţie). Este menţionat
cazul particular al mecanismelor planetare cu o singură roată satelit cu angrenare dublă (exterioară şi
interioară). Pe baza modelului de analiză cinetostatică a mecanismului planetar monomobil cu două roţi dinţate
centrale, în finalul lucrării se abordează o problemă practică de calcul cinetostatic al unui mecanism planetar
cilindric simplu folosit la capul de frezat pentru prelucrarea roţilor dinţate cilindrice cu dinţi curbi în
hipocicloidă.
Keywords: roţi, articulaţie, ecuaţie;
1. MECANISMUL PLANETAR CA MULTIPLICATOR DE TURAŢIE
Asupra arborelui roţii centrale 1 acţionează momentul rezistent M1, iar la arborele de
intrare al braţului port-satelit p acţionează momentul motor Mp (fig. 1a,b)
Fi 2 y
.
Fi 2
Rp2
 R py2
-R02
C
R02
R02
 R px 2
C
‘
C
h
2‘
2
B
R01y
R px 2 B y
B h
Mp B
2
2
Mp R0 p
A
R
R
R
ω1
A
M1
0
a)
p
1
O
ωp
3(0)
21
A
M1O
Mp
b)
R12
21
1
M1
h1 1
O
c)
Fig. 1
12
A
O
x
R01
d)
O
R0xp
e)
1.1. Mecanismul general când roţile satelit 2 şi 2’ sunt distincte
Se consideră ipoteza că se cunoaşte cuplul rezistent M1, acţionând asupra roţii centrale 1 şi
se neglijează forţele de frecare şi de greutate. Astfel, pornind de la echilibrul elementului 1
(fig. 1c), se scriu cele trei ecuaţii de echilibru [1,2]:
  M O1  R21h1  M 1  0

1
x
(1.1)
  Fx R01  R21 cos   0


1
y
 F  R  R sin   0
01
21
 y
unde h1  r1 cos  , în care r1  12 mz1 este raza cercului de divizare, m este modulul roţilor
dinţate şi  este unghiul de angrenare. Din prima ecuaţie (1.1) se obţine mărimea reacţiunii
din angrenajul exterior (1,2) cilindric (fig. 1a,b):
2M 1
R21 
(1.2)
mz1 cos 
112
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Ecuaţiile a doua şi a treia din (1.1) permit calculul componentelor reacţiunii R01 :
2M 1
2M 1
x
y
; R01  R21 sin  
R01
 R21 cos  
tg
mz1
mz1
(1.3,4)
Asupra roţilor satelit 2+2‘ cu masa m2 acţionează forţa de inerţie centrifugală
Fi 2  m2 r1  r2  p2  12 m2mz1  z2  p2
(1.5)
Se izolează elementul cinematic 2(2‘) şi se introduc reacţiunile R12 şi R32'  R02 în
punctele de angrenare A respectiv C (fig. 1.d).
De asemenea, în punctul B se introduc componentele reacţiunii specifice unei articulaţii
plane R px 2 , R py2 , dintre braţul portsatelit p şi roţile satelit 2(2‘).
Echilibrul cinetostatic [1, 3] al corpului 2(2‘), fără considerarea forţei de greutate, se
exprimă prin cele trei ecuaţii (una de momente şi două de proiecţii pe axele x, y ):
  M B2   R12h2  R02h2'  0

2 
x
 Fx R p 2  R12 cos   R02 cos   0
 F 2   R y  F  R sin   R sin   0
p2
i2
12
02
 y
(1.6)
Din fiecare din cele trei ecuaţii (1.6) se deduce în această ordine:
h
2M 1 r2
2M 1 z2
R02  R12 2 

h2' mz1 cos  r2' mz1 cos  z2'
(1.7)
2M 1 
z 
1  2 
mz1  z2' 
  Fi 2  R12 sin   R02 sin  
R px 2   R12 cos   R02' cos   
R py2
(1.8)
(1.9)
2M 1 
z 
1  2 tg
mz1  z2' 
Calculul cinetostatic al mecanismului planetar monomobil (fig. 1a) se încheie cu scrierea
ecuaţiilor de echilibru [3, 4] pentru braţul port-satelit p, fără considerarea forţei de greutate
(fig. 1e):
  12 m2*mz1  z2  p2 
  M O p   R px 2 r1  r2   M p  0

 p
x
x
 Fx R0 p  R p 2  0
 F  p  R y  R y  0
0p
p2
 y
Din fiecare ecuaţie (1.10) se deduce câte o necunoscută:
 z 
z 
M p   R px 2 r1  r2   M 1 1  2 1  2 
z1  z2' 

R0xp  R px 2  
2M 1 
z 
1  2 
mz1  z2' 
R0yp  R py2   12 m2*mz1  z2  p2 
113
(1.10)
(1.11)
(1.12)
2M 1  z2 
1  tg
mz1 
z1 
(1.13)
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1.2. Mecanismul particular cu roţile satelit 2 cu dublă angrenare
Dacă roţile 2 şi 2‘ coincid între numerele de dinţi există egalitatea z2  z2' , astfel că
formulele (1.7), (1.8), (1.9), (1.12), (1.13) pentru calculul reacţiunilor deduse mai sus capătă
expresiile:
4M 1
2M 1
y

2
x
; Rp2  
; R p 2   12 m2 mz1  z2  p
(1.7‘,8‘,9‘)
R02 
mz1
mz1 cos 
4M 1
y

2
; R0 p  12 m2 mz1  z2  p
(1.12‘,13‘)
R0xp 
mz1
Pentru momentul motor acţionând pe braţul portsatelit p, formula de calcul (1.11) capătă
forma
 z 
 z 
M p  2M 1 1  2   M 1 1  3 
(1.11‘)
z1 
z1 


2. MECANISMUL PLANETAR CA REDUCTOR DE TURAŢIE
Asupra arborelui braţului portsatelit p acţionează momentul rezistent Mp, iar asupra
arborelui roţii centrale 1 acţionează momentul motor M1 (fig. 2a,b).
C
2
B
ω 1 M1 A
0
2
p
1
O
ωp
R02
‘
Fi 2
R12
0
R02
-R02
C
A
Mp
1 R21
O
M1
Mp
a)
R12
2(2‘)
h2‘ C
h2 B
A
3(0)
B
3(0)
R py2( R p 2 )
y
Fi 2
y
0p
O
c)
R01y
Mp
R
b)
R px 2 ( R px 2 )
R0xp
M1
A
R21
1 h1
O
x
R01
d)
Fig. 2
2.1. Mecanismul general când roţile satelit 2 şi 2’ distincte
În acest caz se consideră lanţul cinematic format din două corpuri: roţile satelit 2(2‘),
izolate prin îndepărtarea roţilor centrale 1 (din punctul A) respectiv 3(0) din punctul C şi din
braţul portsatelit p, prin desfacerea legăturii din O cu batiul 0 (fig. 2c). Observând că în A şi C
sunt cuple roto-translante (angrenări cilindrice plane), lanţul cinematic diadic (2+p) este
echivalent din punct de vedere structural-topologic cu un lanţ cinematic tip triadă [3].
În continuare se scriu ecuaţiile de echilibru cinetostatic ale acestui lanţ diadic (2+p), fără
forţe de frecare şi de greutate:
(2.1)
 Fx2  Rpx2  R12 cos   R02 cos   0
F   R
M    R
F   R
2
y
2
B
p
x
114
y
p2
 R12 cos   R02 cos   Fi 2  0
(2.2)
h  R02h2'  0
(2.3)
R
(2.4)
12 2
x
0p
x
p2
0
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Editura “Academica Brâncuşi” , Târgu Jiu, ISSN 1844 – 640X
F   R
M    M
p
y
y
0p
p
B
p
 Rpy2  0
(2.5)
 R0xp r1  r2 
(2.6)
Din ecuaţia (2.6) se deduce componenta orizontală
Mp
2M p
(2.7)
R0xp 

r1  r2 mz1  z2 
Ecuaţia (2.1) se scrie ţinând seama de ecuaţiile (2.3) şi (2.4):
h
(2.8)
R0xp  R12 (1  2 ) cos   0
h2'
din care se deduce reacţiunea din angrenajul exterior (1,2)
R0xp z2'
2M p z 2'
(2.9)
R12 

z2'  z2 cos  mz1  z2 z2  z2' cos 
Ecuaţia (2.3) permite calculul reacţiunii din angrenajul interior (2‘,3)
2M p z2
h
R02  R12 2 
(2.10)
h2' mz1  z2 z2  z2'  cos 
Din ecuaţia (2.2) se explicită componenta verticală a reacţiunii din articulaţia B:
Rpy2  R02 sin   R12 sin   Fi 2
(2.11)
sau, ţinând seama de expresiile (2.9), (2.10) şi (1.5) rezultă
2M p z 2  z2 ' 
R py2 
 12 m2*mz1  z2  p2
(2.12)
mz1  z2 z2  z2'  cos 
Ecuaţiile (2.4) şi (2.5) evidenţiază egalitatea componentelor din articulaţiile O şi B:
R px 2  R0xp ; R0yp  R py2
(2.13)
În final se scriu ecuaţiile de echilibru cinetostatic pentru roata dinţată centrală 1 (fig. 2d):
  M O1  R21h1  M 1  0

1
x
(2.14)
  Fx R01  R21 cos   0
 F 1  R y  R sin   0
01
21
 y
Se observă că toate cele trei ecuaţii sunt decuplate, astfel că din fiecare se deduce câte o
necunoscută în ordinea corespunzătoare:
z1 z2'
M1  R21h1  M p
(2.15)
z1  z2 z2  z2' 
x
R01
  R21 cos  
 2M 1
;
mz1
R01y  R21 sin  
2M 1
tg
mz1
(2.16,17)
2.2. Mecanismul particular cu roţile satelit 2 cu dublă angrenare ( 2  2' )
În formulele deduse mai sus se face z2  z2' şi rezultă următoarele expresii:
R0xp  R px 2 
115
2M p
mz1  z2 
;
R0yp  Rpy2   12 m2*mz1  z2  p2
(2.7‘,12‘)
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Editura “Academica Brâncuşi” , Târgu Jiu, ISSN 1844 – 640X
R12 
Mp
mz1  z2  cos 
R02 
;
Mp
(2.9‘,10‘)
mz1  z2  cos 
1
M
 z 
z1
 2M 1
2M 1
y
; R01 
(2.16‘,17‘,15‘)
 M p 1  3 
R 
tg ; M 1  p
2 z1  z2
z1 
mz1
mz1

În ultima formulă (2.15‘) s-a folosit relaţia dintre numerele de dinţi z1  2 z2  z3 . Se
verifică acest rezultat cu formula (1.11‘).
x
01
3. CALCULUL CINETOSTATIC AL MECANISMULUI PLANETAR CILINDRIC CU
LANŢURI PARALELE
Mecanismele planetare cu roţi dinţate cilindrice sunt realizate de obicei cu două sau mai
multe roţi satelit montate în paralel (fig. 3), prin acest montaj realizându-se atât echilibrarea
maselor rotative cât şi micşorarea efortului dintr-un angrenaj. Din punct de vedere structuraltopologic şi cinematic, roţile dinţate montate în paralel sunt elemente cinematice pasive,
mişcarea acestor roţi satelit fiind teoretic identică.
Practic însă, datorită elasticităţii şi abaterilor tehnologice, roţile dinţate montate în paralel
nu se comportă ca elemente pasive, ceea ce determină o tendinţă de blocare a mecanismului.
Fi 2
Fi 2
C
ω 1 M1 A
0
R02
2‘
B
2
1
O
p
3(0)
ωp
0
R12
Mp
-R02
‘
2 C2
B
R21
pA
3(0)
Mp
b)
pA
R02
Fi 2
-R02
3(0)
Mp
1 R21
MO
1
B
-R02
Fig. 3
C 2‘
2 B
R12
1 R21
O
M1 R12
B
a)
R02
Fi 2
B
Fi 2
c)
Jocurile dintre dinţi poate compensa nedeterminarea structural-topologică şi cinematică,
datorită abaterilor de montaj, dar nu elimină încărcarea dinamică neuniformă a roţilor satelit
legate în paralel.
S-au propus şi încercat diferite procedee pentru distribuirea uniformă a sarcinilor statice şi
dinamice pe roţile dinţate montate în paralel, dar aceste metode nu s-au generalizat.
De obicei, în calculul cinetostatic al mecanismelor cu roţi dinţate legate în paralel se
consideră o distribuţie uniformă pe toate roţile montate în paralel (fig. 3), compensându-se
erorile introduse prin această ipoteză prin impunerea unor coeficienţi de siguranţă mai mari.
3.1. Mecanismul ca multiplicator de turaţie
În varianta mecanismului multiplicator de turaţie (reductor de cuplu) M p  M m ,
M1  M r , astfel că reacţiunile se calculează conform algoritmului folosit anterior cu ajutorul
ecuaţiilor implicite (1.1.1), (1.1.6) şi (1.1.10) deduse din echilibrul cinetostatic.
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Pentru mecanismul planetar cu ns sateliţi, de exemplu ns  2 (fig. 3b) şi ns  3 (fig. 3c),
reacţiunile se calculează cu formulele:
2M 1
2M 1
z2
x
y
; R01  0 ; R01  0 ; R02 
(3.1-4)
R21 
ns mz1 cos 
ns mz1 cos  z2'
2M 1 
z 
2M 1 
z 
1  2  ; R py2   12 m2*mz1  z2  p2 
1  2 tg
ns mz1  z2' 
ns mz1  z2' 
 z 
1
z 
M p  ns R px 2 r1  r2   M 1 1  2 1  2  ; R0xp  0 ; R0yp  0
ns
z1  z2' 

R px 2  
(3.5,6)
(3.7-9)
3.2. Mecanismul ca reductor de turaţie
În varianta mecanismului reductor de turaţie (multiplicator de cuplu) roata dinţată 1 este
element motor ( M 1  M m ), iar braţul portsatelit este element condus ( M p  M r ), situaţie în
care reacţiunile se calculează cu ajutorul ecuaţiilor implicite de echilibru cinetostatic (2.1-6) şi
(2.14).
2M p
2M p z2'
2M p z2
;
; R02 
R0xp 
R12 
ns mz1  z2 
ns mz1  z2 z2  z2'  cos 
ns mz1  z2 z2  z2'  cos 
(3.10-12)
R py2 
2M p z2  z2' 
 12 m2*mz1  z2  p2 ; R px 2  R0xp ; R0yp  R py2
ns mz1  z2 z2  z2'  cos 
M
z1 z2'
 2M 1
2M 1
x
y
M1  p
; R01 
; R01 
tg
ns z1  z2 z2  z2' 
ns mz1
ns mz1
(3.13-15)
(3.16-18)
4. CINETOSTATICA MECANISMULUI PLANETAR SIMPLU CU O SINGURĂ
ROATĂ CENTRALĂ FIXĂ
Se consideră mecanismul planetar cu angrenajul interior, la care braţul portsatelit p este
conducător şi roata satelit 2 este element condus (fig. 4).
Fi 2
Fi 2
-R02 C
R02
B 2
1(0)
A
F
r
Mp p
C
B
3
2
Fr A p
O
1(0)
ωp
0
O
Mp
-R02
A
Mp
B
a)
R02
-R02
b)
Fi 2
p
R02
3(0)
Fr
O
R02
B
C
B 2
-R02
B
c) R02
-R02
Fi 2
Fi 2
Fig. 4
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Roata dinţată centrală 1 este fixată de batiul 0 (fig. 4a). Cuplul motor Mp acţionează braţul
portsatelit p , iar asupra roţii dinţate satelit 2 acţionează forţa rezistentă Fr perpendiculară pe
braţul portsatelit OB (fig. 4b).
Forţa Fr este de rezistenţă tehnologică, ea se manifestă dinspre roata prelucrată 3 şi care
apasă asupra cuţitelor montate în punctul A la distanţa AB  r2  12 mz2 de axa arborelui roţii satelit 2.
Valoarea forţei rezistente Fr depinde atât de duritatea materialului din care se prelucrează
roata cu dantură hipocicloidă [5], cât şi de grosimea aşchiei care este evaluată prin avansul
piesei brute fixată pe platoul din faţa capului de frezat. Roata brută (3) execută două mişcări
de avans, una de rotaţie (υrb) şi alta de translaţie (srb), putând fi aşezată în poziţia verticală
(fig. 4) sau mai eficient într-o poziţie orizontală, când fixarea se realizează cu dispozitive
adecvate (fig. 5).
C
2
B
A
p
1(0)
ωp
Mp
O
3
υrb
srb
Fig. 5
Pornind de la forţa rezistentă Fr, cunoscută şi aplicată în punctul A, se calculează, din
echilibrul cinetostatic al roţii dinţate 2 (fig. 4b,c), reacţiunea din angrenajul interior (2,1),
considerând ecuaţia de momente faţă de punctul B:
Fr
(4.1)
R02 
ns cos 
unde ns este numărul roţilor satelit montate în paralel.
Componenta orizontală din articulaţia B se deduce din ecuaţia de momente, în raport cu
punctul C, a forţelor care acţionează pe roata satelit 2 (fig. 4b,c):
R px 2  2 Fr
(4.2)
Componenta verticală din articulaţia B se calculează din ecuaţia de proiecţie pe axa y:
R py2  Fr tg  m2*mz1  z2  p2
(4.3)
Din echilibrul barei portsatelit p se calculează componentele reacţiunii din lagărul O,
reprezentând articulaţia (0,p) şi în mod deosebit valoarea cuplului motor Mp:
M p  Rpx 2 r1  r2   mFr z1  z2 
(4.4)
Acest cuplu motor permite calculul puterii necesare pentru capul de frezat [5] şi implicit
alegerea motorului electric de acţionare a dispozitivului.
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Bibliografie
1. Antonescu, P., Cinetostatica şi dinamica mecanismelor, Lito UPB, Bucureşti, 1980.
2. Handra-Luca, V., Introducere în teoria mecanismelor, vol. II, Editura Dacia Cluj
Napoca, 1983.
3. Antonescu, P., Antonescu, O., Mecanisme şi dinamica maşinilor, Editura Printech
Bucureşti, 2005.
4. Margine, A., Contribuţii la sinteza geometro-cinematică şi dinamică a mecanismelor
planetare cu roţi dinţate cilindrice, teză de doctorat, UPB, 1999.
5. Ghionea, A., Contribuţii la cercetarea teoretică şi experimentală a prelucrării roţilor
dinţate cilindrice cu dinţi curbi, teză de doctorat, UPB, 1980.
6. Antonescu, O., Antonescu, P., Ghionea, A., Cinetostatica mecanismelor planetare
cilindrice, rev. Mecanisme şi Manipulatoare, Vol. 6, nr. 1, 2007, p. 13-18.
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CONTRIBUTIONS TO THE IMPLEMENTATION OF
ENVIRONMENTAL MANAGEMENT SYSTEM WITHIN THE ECO
TECHNOLOGIC ORGANIZATION
Prof. univ. dr. ing. Gheorghe AMZA, Polytechnic University of Bucharest, Romania,
[email protected]
Prof.univ. dr. ing. Dan DOBROTA, ‖Constantin Brâncusi‖ University of Târgu - Jiu,
Romania, [email protected]
Abstract: This paper presents contributions to the implementation of environmental management system within
the eco technologic organization.
SME type organization's environmental policies highlights the
accomplishment of requirements of ISO 19001 standard, regarding pollution prevention, commitment in
accordance to the law and if it is documented and can provide a framework for setting environmental objectives
and targets. The audit may reveal whether it corresponds to the nature, scale and impact that activities, products
and services of the organization have on the environment, or if it is implemented, maintained and communicated
to all staff. This paper presents mainly the following: elements of environmental planning process,
environmental planning process, place of environmental conservation in the general strategy of the organization
Keyworks: implementation, environmental, eco technologic, management system.
1. INTRODUCTION
The task of achieving consistency between population growth trends, the desire for
continuous development of the organization and the need to protect the environment can be
met only through an approach that encourages and supports development and environment
simultaneously.
The development of eco technologic organizations represents a new approach of
industrial development that enables organizations to ensure economic and social benefits for
the present generation without compromising the ability of future generations to meet their
own needs without damaging the fundamental ecological processes.
From this definition follows that any significant degradation of ecological processes, due
to industrial organizations should not be on long term. To achieve sustainable development of
the organization three criteria have to be met:
- protection of eco-capacity, namely maintenance of the capacity of ecosystems to
function in spite of pollution;
- efficient use of human, material and energy resources;
- ensuring a fair distribution among nations both of the goods supplied by the
development of organizations as well of the hardships caused by environmental degradation.
The eco production concept evolves from earlier concepts of eco-technology and clean
technology or low-waste production. The older concept of clean technology was regarded by
the European Community Commission in 1979 as having three distinct but complementary
goals:
- fewer pollutants discharged into the natural environment (air, water, soil);
- less waste (waste-free technology or low-waste production);
- lower demand for natural resources (water, energy and raw materials).
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Although there is still no universally agreed definition of eco production, nor do any
sustainable development, there is some consensus expressed at the seminar to promote clean
production, organized by the United Nations Environment Program.
Eco production is a global approach of environmental protection, which includes all
phases of production or product life cycle, mainly aimed to prevent and minimize short-and
long-term risks for humans and the environment.
Eco production is beneficial to the environment by reducing pollution. Also, eco
technologic organizations following this type of preventive pollution approach, have some
direct benefits, such as:
- achieve cost savings by reducing waste of energy and raw materials;
- improving the efficiency of the organization;
- achieving a better quality of products, since the operation of the organization is
easier to predict;
- recovery of wasted certain materials.
Eco production includes the following:
- application of expertise;
- improving technology;
- changing attitudes.
By the new approach born in environmental management, the priorities of pollution
management are completely reversed. Thus, the first hierarchic priority is to prevent pollution,
according to changes of the processes and products, recycling and recovery of production site,
before taking measures to reduce pollution. This new hierarchy looks like this:
- prevention;
- reduction;
- reuse and recycling;
- treatment with energy and material recovery;
- treatment;
- final disposal.
This approach of environmental management is growing because of the fact that eco
technologic organizations, especially companies applying technical progress:
- realize that new priorities are less expensive and therefore it is a more profitable
environment management;
- are aware that sooner or later they will be forced by public pressure or Government
to reduce pressure of environmental pollution.
Steps necessary to implement a program to achieve an eco production in an
organization can be summarized as follows:
- develop and implement a comprehensive environmental policy at corporate level to
focus on preventing pollution.
- setting some corporate objectives regarding the program of introduction of eco
production by establishing a precise agenda.
- allocation of responsibilities, time and financial support for the entire program;
- employees‘ involvement at all levels;
- develop accounting procedures for the reduction of waste in the company and their
regular use to identify, assess and eliminate waste at every stage of production;
- obtaining and using the best technical and other information from both inside and
outside the company;
- monitoring and evaluating progress of the program;
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- regular information of all company‘s employees on progress in connection with eco
production from the last month, from the last six months, the last year or last five years;
- encouraging and rewarding fruitful individual and collective efforts in eco
production‘s implementation;
- awareness that achieving eco production is a journey and not a destination;
- regular modernization of objectives and timetables to minimize the amount of waste.
2. REQUIREMENTS FOR ENVIRONMENTAL POLICY
Environmental policy is the only the framework for setting environmental objectives and
specific environmental targets. There are however certification bodies requiring, that these
objectives to be explicitly included in the policy.
SME type organization's environmental policies highlights the accomplishment of
requirements of ISO 19001 standard, regarding pollution prevention, commitment in
accordance to the law and if it is documented and can provide a framework for setting
environmental objectives and targets. The audit may reveal whether it corresponds to the
nature, scale and impact that activities, products and services of the organization have on the
environment, or if it is implemented, maintained and communicated to all staff.
PROCESS INPUTS:
- supplied materials and products;
- semi finished products;
-
power;
water;
air;
other materials.
MANUFACTURING PROCESSES, ACTIVITIES,
SERVICES, AUXILIARIES
PROCESS OUTPUT:
-
finite products;
sub products;
realized service;
waste;
air, water soil exhaustions;
vibration and noice;
consumption of resources.
Figure 1. Elements of environmental planning process
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It is indicated that environmental issues identified at the outset to completely reflect the
real situation of an organization against the environment. Not to lose sight the essential
aspects, it is appropriate to consider each process analyzed within scheme shown in figure 1,
that should be customized for each examined process.
Also, setting environmental goals, targets and programs must necessarily consider
significant environmental aspects. The sequence indicated in figure 2 must be followed.
ENVIRONMENTAL
POLICY
ENVIRONMENTAL
OBJECTIVES
ENVIRONMENTAL
SIGNIFICANT ASPECTS
ENVIRONMENTAL
TARGETS
ENVIRONMENTAL
PROGRAM
ENVIRONMENTAL
LEGISLATION
Figure 2. Environmental planning process
It is essential that management reviews to be strictly conducted within the terms
specified and regularly. Such analysis must always rely on some clearly defined input data,
showing how the system works, the degree to which the objectives and targets are
accomplished, the problems, identified nonconformities, deviations from the planned
approach and the proposed targets. Analysis of the above indicated aspects should always be
done with functions involved and those which can offer solutions, but also to those having
responsibilities in implementing the actions to be determined. Presence of the environmental
management representative is always required. Analyses made by management may be more
effective if based on the results obtained by one or more teams, who have previously applied
techniques to identify the causes that have led to environmental problems, to nonconformances, to deviations or undesirable impacts from the established objectives.
Analysis made by management must always lead to certain decisions, namely the
corrective and preventive actions, or to confirm, correct or generalize some certain previously
taken actions. These results should always be documented on forms to allow their tracking. In
the forthcoming review meeting application and effectiveness of established measures must
necessarily be verified. Where failures or inefficiencies are found corrective action must
necessarily be taken. Management analysis and in particular, decisions on these occasions in
order to meet and positive spirit of our own of continuous improvement that the standard
promotes must be used. According to the above mentioned, all the leverage that the standard
offers and even those aimed at updating the policy, objectives and targets should be
considered.
For a better approximation of reality and a higher accuracy the following content of
analysis scales, divided into five levels of representation of environmental phenomena and
processes in the overall effort, and the fields, at the level of eco technologic organization is
proposed.
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The place of environmental conservation in the general strategy of the organization is
presented in table 1.
Table 1. Place of environmental conservation in the general strategy of the organization
Presentation level (elements)
1 Hierarchical level to assume the environmental responsibilities
2 Share of medium expenses (less investment) in the organization's
budget
3 Investment for environmental conservation
4 The importance attached to internal communication policy in
environmental management
5 The importance of external communication policy in environmental
management
6 The importance given to increasing number of supporters greening
activity
7 Efficient distribution (effective and economical) of environmental
responsibilities
8 Perceiving need for greening of the activity for internal business
environment organization
9 Perceiving need for greening of the activity for external business
environment organization
10 The share of environmental problems in research and development.
The level of presentation (items) (Msg)
1
2
3
*
4
5
*
*
*
*
*
*
*
*
*
Msg = (ΣEi/50) · 100[%]
Ei = the level of
representation of i
elements
Msg =(41/50)·100=82[%]
Assessment of global importance given to environmental conservation in the overall
strategy Msg of the organization has as its starting point the hierarchic level to assume
environmental responsibilities, this practice recording several situations, giving notes:
1. assuming responsibilities by the general manager;
2. assuming responsibilities of a department dealing with:
 public relations;
 supervision and control of quality production;
 security in the conduct of technical and productive processes;
3. assuming responsibilities by several departments;
4. assuming responsibilities of a specialized department;
5. assuming responsibilities by the entire organization.
Coverage of environmental conservation in the organization's strategy is realized by
calculating the presentation level Msg presentation, with the relationship:
10
 Ei
 100%
50
where: Ei is the representation level of ‖i‘‘ elements.
In the above mentioned case, the Msg presentation level is:
Msg 
124
i 1
(1)
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M sg 
41
100  82%
50
(2)
3. CONCLUSIONS.
In conclusion, it can be affirmed that according to scales resolved in the organization
the production strategy obtained the highest score. This is very important because in any
organization a higher production is required to be obtained as the company to achieve
foreseen profits. Second place was taken by legal and financial strategy with the level of
representation of 88%, this revealing that the company complies with state laws with great
care in this respect.
General strategy to the environmental problems with a representation level of 82%
occupies the third place, followed in fourth place by the communications strategy, revealing a
growing interest in communication, with implications for both internal communication and
external communication, as internal communication gives consistency to the mechanism of
transmission of the image enhancing efficiency of external communication.
Imposing command and control regulations on eco technologic organization, is a
contested process, often involving substantial legal costs and more delays. If eco technologic
organization representatives are eager to cooperate, the Government may negotiate planned
arrangements. A planned understanding represents a guarantee of eco technologic
organization to meet environmental objectives that are acceptable for the government. This
method works well in sectors that have relatively few organizations, but high capacity (United
Nations Industrial Development Organization, 2002).
REFERENCES
1. Amza, Gh., - Eco technology and sustainable development, publisher Printech, Bucharest,
2009.
2.Amza, Gh., Pîrvulescu Mihaela- Achieving sustainable development of a mathematical
model of manufacturing organization eco technology welded construction, TQSD, Bucharest,
2008
3. Gore, Al., Earth in the Balance. Ecology and the Human Spirit, Penquin Books, U.S.A.,
1993.
4. Hart, S.L., Greening, B., - ―Strategies for a Sustainable World", Harvard Business Review
on Business and the Environment, Cambridge: Harvard University Press, p. 108, 2000.
5. Oprean, C., Bucur, A., Vanu, A., „A mathematical model of the innovation indicator"
Balkan Region Conference on Engineering and Business Education & International
Conference on Engineering and Business Education, Sibiu, Romania. 15-17 October,
publishing Lucian Blaga Univesrsity of Sibiu, 2009.
6. Oprean, C., Vanu, A.,‖Leadership and organizational wellness‖, Review of Management
and Economical Engineering, Cluj-Napoca, Romania, volume 8. No.2 (32), 2009
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IMAGE SEGMENTATION FOR INDUSTRIAL QUALITY
INSPECTION
Dr.Catalin Gh. AMZA, Universitatea Politehnica din Bucuresti, [email protected]
Dr.Gheorghe AMZA, Universitatea Politehnica din Bucuresti, [email protected]
Dr.Diana POPESCU, Universitatea Politehnica din Bucuresti, [email protected]
Abstract: The contaminant detection process of an industrial product is an important stage of a modern
production factory. The large demand of quality products has lead producers to use automated systems. One
such system is the automated detection of defects/contaminants. An X-ray image of the product is taken and
automatically analysed by the system. The most important step of the process of inspecting that product is the
segmentation of the image into meaningful objects (defects and normal product). This paper presents an original
approach along with other classical techniques for the segmentation of dual-band X-ray images of industrial
products.
Keywords: image segmentation, Hopfield neural networks, industrial quality inspection
1. INTRODUCTION
There are just a few products of industrial processes so well defined that their quality can be
guaranteed to meet exactly the client specifications or requirements. However, in most areas
of industrial processing some sort of testing or inspection has to be performed on intermediate
or final products [1]. When dealing with small and simple batch products, it is easy and
inexpensive to perform destructive testing on a sample of components, but in most of the
industrial cases, non-destructive inspection techniques are employed.
Image segmentation is the first and the most important step in a contaminant/defect
detection/inspection system used in the industry. Whereas such a system is used for detection
of metallic or non-metallic contaminants (e.g. glass, bones and stones) or for detection of
flaws or cracks), it usually involves some means of acquiring one or more images of the
inspected product. The most important type of image used in commercial inspection systems
is the X-ray image [1]-[5]. The detection of defects has to be reliable and cost efficient while
performed with high speed [1]. Most segmentation methods currently rely on simple
thresholding algorithms [7], [8], [9]. This paper concerns the use of a Competitive Hopfield
Neural Network (CHNN) for the segmentation process of a dual-band image of industrial
products.
2. EXPERIMENT
2.1. Classical approaches to x-ray images segmentation
A segmentation algorithm for an X-ray image needs to separate foreign objects (such as
defects or contaminants) from the background (the normal product). One aims in separating
not only entire objects from the background, but also separating only parts of objects from the
background is also considered a successful technique. A simple thresholding of a the X-ray
image would provide a useless result for further image analysis techniques. To illustrate this,
an Otsu-based algorithm was implemented [8]. The product (an aluminum faucet obtained
through casting – Fig. 1) contains three easily visible defects (Fig. 2 left).
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A dual-band X-ray image [10] of the product has been acquisitioned (an image consisting
of one high-energy and one low-energy X-ray images). Fig. 2 depicts the high-energy and
low-energy X-ray images taken from the product. When thresholding the image, defects are
merged with other parts of the background (normal product) and therefore, a correct
extraction of important objects is not possible in this way, due to the fuzziness of the obtained
X-ray dual-image. Therefore, multilevel thresholding techniques need to be employed to solve
the segmentation problem.
Classical edge enhancement and detection techniques were also tested on the X-ray images.
The aim here is to have a resultant image that contains contours for the foreign objects
embedded in the product. The idea under lying edge detection is the computation of a local
derivative operator. The first derivative of an edge modeled in this manner is 0 in all regions
of constant grey level and constant during a grey-level transition. The first derivative of an
image is called gradient. Results of applying classical edge detection techniques on a detail Xray image (Fig. 3) are depicted in Fig. 4.
Classical methods of image segmentation applied to X-ray images with respect to an
inspection system have proven to render results that are not very useful for further image
analysis such as high-level detection (due to the merging between foreign-bodies and the
surrounding background). Since image segmentation output is the input to consequent image
processing techniques, one wants that output to be of a high quality. The segmentation
process can also be seen as a constraint optimization problem. The constraints, in this case are
based on the fact that objects extracted from the image needs to be homogenous and different
from each other for instance. Thus, an alternative approach to image segmentation was
implemented by using a Hopfield Neural Network architecture.
Fig. 1. A part obtained through casting used for
experiments
Fig.3. X-ray detail of the faucet
127
Fig. 2. Dual band X-ray image of the faucet
Fig. 4. Classical Image segmentation
algorithm results (Laplace – left, Gradient –
right)
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2.2. Hopfield Neural Networks
Hopfield neural network (HNN) was proposed in 1985 by Hopfield as a way of solving
optimization problems [11]. In a HNN each neuron is linked to another and weights are
symmetrical, i.e. wij=wji, where wij represent the weight of connection between neuron i and j.
There are no input or output neurons, but rather all the neurons look and act exactly the same.
Inputs are applied to all neurons at the same time. The network for the optimization
application tends to relax into stable states that minimizes an energy function of a Lyapunov
form [11], [12], [13]:
N
N
N
E   wij vi v j   I i vi
i 1 j 1
i 1
(1)
where N is the number of neurons, vi is the output of the ith neuron , and Ii is the external input
for the ith neuron term. Hopfield demonstrated that HNN relax into a stable state tending to
minimize its corresponding energy function. The behavior of the network in time can be
determined by differentiating E with respect to vi. The updating algorithm for a neuron i, at a
given moment in time t is:
[t ]
[ t 1]
(2)
vi   wij v j
The strategy used by the majority of the authors comprises two steps: firstly to find a
binary representation for the segmentation solution, so that it can be mapped into a HNN
stable state; and secondly, to define the energy function whose minimization will lead to an
optimum solution to the problem. A Hopfield neural-network assigns each grey-level to a
class according to a ―goodness of segmentation‖ criteria. If a neuron (i,j) is active, then its
corresponding grey-level i is assigned to class j. One grey-level can only be assigned to one
class. The problem of segmenting an image of n by n pixels into k classes is to choose a
suitable architecture for the HNN. In this study, we follow the ideas proposed in [14], [15],
[16]. The solution of the segmentation process using a binary representation can be mapped
using a grid of P rows of k neurons. The columns of this architecture represent the classes in
which the image has to be segmented. The rows correspond to the objects that have to be
assigned to a class according to some constraints. An approach taken by [7] is to use a grid of
P by k neurons, where P is the total number of pixels in the image. Thus, the number of
neurons in this approach is n x n x k . The computations associated with the behavior of such a
neural network are very complex and unsuitable for a real time application. The complexity of
such an approach can be decreased severely as in [16], [17]. Their HNN consists of a similar
grid of N by k neurons, but in this case N is the number of grey-level values found in the input
image (see Fig. 4). The number of neurons decreases dramatically to Nxk. This makes this
architecture not only manageable from the point of view of computations involved, but also
independent of the size of the image.
An energy function associated with a HNN must comprise terms for image segmentation
constraints Esyntactic or syntax energy i.e. to ensure that no grey-level or pixel can belong to
two classes at the same time, and terms for goodness of segmentation, Esemantic or the semantic
energy:
(3)
E  Esyntactic  Esemantic
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Using the binary mapping mentioned above, the segmentation constraints can be
summarized as follows: only one neuron per row can be active (output is 1); this puts each
grey-level into one class (left term of equation (4)); the sum of outputs of all neurons in one
row is 1, this ensuring the fact that each grey-level belongs to only and only one class (right
term of equation (4)):
2
N
N k
k
 k

E systactic      v xi  1    v xi v xj
x 1  i 1
x 1 i 1 j 1

(4)
j i
where α and β are constant values.
Class 1
Class 2
Class k
1,1
1,2
1,k
2,1
2,2
2,k
grey-level(2)
N,1
N,2
N,k
grey-level(N)
grey-level(1)
Fig.4 HNN architecture
The ―goodness‖ of segmentation has to be measured by the following properties. Firstly,
segments have to be uniform and homogenous with respect to grey-level values. Secondly,
adjacent regions or segments have to have significant differences with respect to their
uniformity (in this case the grey-level values). Thus, the semantic energy is defined in this
case as the sum of square distances from each grey-level to the center of its class. By
minimizing the energy, these distances decrease to a minimum leading to a solution for the
segmentation. Due to the fact that two images are taken for each product, one high-energy Xray and one low-energy X-ray image, a semantic energy for both images has to be defined as
follows:
N1
N1
k
E semantic1   
x 1 y 1 i 1
1
N
 hl y v yi
y 1
N2 N2
k
v xi DIS xy hl y v yi   
x 1 y 1 i 1
1
N
 hhy v yi
y 1
v xi DIS xy hh y v
(5)
where N1 , N2 are the number of grey-levels present in the low-energy respectively highenergy image,  and δ are constants and hly and hhy are the histogram values of the y greylevel for the low-energy band and high-energy band image respectively.
An important aspect in the process of defining the semantic energy is choosing the
appropriate measure of distance DISxy. This represents the distance between grey-level lx and
grey-level ly. Because the present method is actually a cluster analysis algorithm, a good
segmentation can be defined by having spherical or ellipsoidal clusters. The squared Euclidian
distance will allow hyperspherical distribution of clusters, formula that was used to determine
DISxy:
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DIS x , y  d lx ,l y  l x  l y 
2
(6)
Using (4), (5) and (6) into (3) we derive the formula for the energy:
2
N
N
k
k
N
 k

E      v xi  1     V xi V xj   
x 1  i 1
x 1 i 1 j 1
x 1

j i
N
k

y 1 i 1
1
N
 (hl
y 1
y
v xi (l x  l y ) 2 (hl y  hh y )v yi
 hh y )v yi
(7)
where N = max(N1, N2).
A simplification of the energy equation can be done using a Winner Take All (WTA) scheme
transforming HNN into a competitive architecture (CHNN). The input-output function for a
neuron is modeled as to satisfy the constraints of the energy function. For every row, only one
neuron can be active. The neuron that receives maximum input from all other neurons is
declared winner and its output is set to 1; the output of the rest of neurons for the same row is
set to zero:
V x ,i
x 1.. N
i 1..k



1, if u x ,i  max  v x ,i 

 i 1..k 
0, otherwise

(8)
In other words, only one neuron is assigned 100% to a class. This satisfies the syntactic
energy terms, therefore the energy equation (7) can be simplified to:
N
E 
x 1
N
k

y 1 i 1
1
N
 (hl
y 1
y
 hh y )V yi
V xi DIS xy (hl y  hh y )V yi
(9)
Comparing equation (9) with the definition of the Lyapunov energy (1) one can compute the
updating equation for the interconnection weights when no bias or threshold is present:
w( x ,i )( y , j )  
x , y 1.. N
i , j 1..k
1
N
 (hl
y 1
y
 hh y )V yi
V xi DIS xy (hl y  hh y )V yi
(10)
where Vxi and Vyi are the binary values for the output of neurons (x,i) and (y,i). Because the
number of weights that needs to be updated is high, using the updating formula (2) and the
weights updating formula (10), we have an equation for the total input to the neuron (x,i) :
v xi  
1
N
 (hl
y 1
y
 hh y )V yi
N

y 1
DIS xy (hl y  hh y )V yi
(11)
An algorithm was designed and implemented using the above equations. Segmentation into 3,
4 and 6 classes is depicted in Fig. 5 (for the image shown in Fig. 3).
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Fig. 5. CHNN segmentation into 6 classes (left) and 4
classes (right)
Fig. 6. CHNN segmentation into 3 classes
While classical algorithms may be able to detect some defects, CHNN successfully
detects all defects, even though some of them only partially. Furthermore, during
experimentation, it has been established that CHNN performs better on dual-band images than
on single-band images, where some of the defects are missed. Since the number of classes
must be specified a priori, further experimental work is necessary in order to find its optimum
value. As it can be seen from Fig. 6, the segmentation into a large number of classes will lead
to increased fragmentation of the segments, while the result of segmentation into only 3
classes (Fig. 6) is not satisfactory. The best results are obtained for 6 classes.
3. CONCLUSIONS
This paper concerns with using a Hopfield Neural Network in conjunction with a Winner
Take All mechanism for segmentation of dual-band X-ray images. The number of
computations associated with this algorithm is lower in comparison with other segmentation
techniques proposed, i.e. morphological filtering [1]. The major advantage of this technique is
the fact that only the histogram information of both images is used as opposed to spatial
constraints that will lead to increased overhead. This study proved the applicability of CHNN
for the detection of foreign bodies within a X-ray image. Future work will concentrate on
minimizing even further the computational overhead involved and finding some means of
post-processing the result.
Acknowledgments: The work has been co-funded by the Sectoral Operational Programme
Human Resources Development 2007-2013 of the Romanian Ministry of Labour, Family and
Social Protection through the Financial Agreement POSDRU/89/1.5/S/62557.
References
1. C.G. Amza, Intelligent X-ray Imaging Inspection System for the Food Industry, PhD
Thesis, De Montfort University, Leicester, United Kingdom (2002)
2. K.J. Burnham, Image segmentation, patent no. US2004/0258305 A1 (2004)
3. G.E. Georgeson, System, method and apparatus for the inspection of joints in a
composite structure, patent no. US2003/0154801 A1 (2003)
4. E.J., Morton, et al., X-ray scanning system, patent no US7684538B2 (2010)
5. T. Moritake, et al., X-ray shielding device, patent no.US7500785 B2 (2009)
6. C.G. Amza, G. Tasca, Segmentation of Industrial X-ray images, Proceedings of the 4th
WSEAS International Conference on Computational Intelligence CI’10, Bucharest,
Romania, 2010, pp.54-59, ISSN: 1790-5117, ISBN 978-968-474-179-3 (2010)
7. J.E. Koss, F.D. Newman, T.K. Johnson, D.L. Kirch, Abdominal organ segmentation
using texture transforms and a Hopfield neural network, IEEE Transactions on Medical
Imaging, (1999) vol.18, no.7, pp.640-648,
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Fiabilitate si Durabilitate - Fiability & Durability Supplement no 1/ 2012
Editura “Academica Brâncuşi” , Târgu Jiu, ISSN 1844 – 640X
8. N. Otsu, A threshold selection method from grey-level histograms, IEEE Trans. On
systems, man and Cybernetics, vol. SMC-9, no.1, pp.62-66, (1979)
9. N.R. Pal, S.K. Pal, A review on image segmentation techniques, Pattern Recognition,
(1993), vol.26, no.9, pp.1277-1294
10. C.G. Amza, Intelligent x-ray imaging inspection system for composite materials with
polymeric matrix, Revista de materiale plastice, (2007) , nr.4, vol. 44(4), pp. 326-331
11. J.J. Hopfield, Tank, D.W., ―Neural‖ Computation of Decisions in Optimisation Problems,
Biol.Cybern., (1985) vol.52, pp.141-152
12. J.J. Hopfield, Neural networks and physical systems with emergent collective
computational abilities, Proc. Natl.Acad.Sci., USA, vol.79, pp.2554-2558, April (1982)
13. J.J. Hopfield, Neurons with graded response have collective computational properties like
those of two-state neurons, Biophysics: Proc.Natl.Acad.Sci., USA, (1984) vol.81,
pp.3088-3092
14. R. Poli, G. Valli, Hopfield neural networks for the optimum segmentation of medical
images, Handbook of Neural Computation, Oxford University Press, chapter.G5.5, pp.110, (1997)
15. D. Popescu, D. Anania, C.G. Amza, G. Amza, T. Cicic, Intelligent x-ray based training
system for pedicle screw placement in lumbar vertebrae, Academic Journal of
manufacturing Engineering, (2011) vol.9, Issue 1/2011, pp. 94-100, Ed. Politehnica,
ISSN 1583-7904
16. K.S. Cheng, J.S. Lin, C.W. Mao, The application of competitive Hopfield Neural
Network to medical image segmentation, IEEE Transactions on Medical Imaging, vol.15,
no.4, pp.560-567, August (1996)
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THEORETICAL AND EXPERIMENTAL CONTRIBUTIONS
REGARDING MATERIALS USED IN PRODUCTION OF ACTIVE
ELEMENTS OF ULTRASONICS MOTORS-PROPERTIES,
SINGULARITY PIEZOCERAMIC MATERIALS PIC 151, 155, 255
Oana Roxana CHIVU, Ilie PRISACARIU, Constantin RADU
―POLITEHNICA‖ University of Bucharest, Splaiul Independenţei no. 313 Street, ROMANIA
―Stefan Cel Mare‖ University of Suceava
[email protected]; [email protected]; [email protected];
Abstract. In this article we present main characteristics of materials used at the construction of ultrasonic
motors. Also, there is presented the mode of determination of material's properties of active elements used in
ultrasonic motors.
Keywords: Ultrasonic Motors, Piezoelectric materials.
1. Introduction
From the crystallographic point of view, this materials have a crystalline structure called
perovskite type. This structure will be found at a lot of series by compounds with three types
of atoms and general formula by form ABCx.
Main piezoceramic materials used in our days, PbTiOx - PbZrOx type, are made from by
lead oxide, titanic oxide, zirconium oxide. The BaTiOx ceramic is also used. This materials
aren't ferroelectrics materials at the temperature called ―Curie temperature‖. They have a
paraelectric behaviour. From an electric point of view under Curie point, crystal lines
materials are neutrals and presents distortions, and the consequence is development of
rhombohedrical and tetragonical crystalline pole and phasewhich have interest for
piezoelectric technology.
In case of PZT, ideal cubic perovskite structure solids solutions are described by
Golschmidt mathematical equation, like:
t
R A  R0
2 RB  R0 
(1)
Notations: RA, RB, R0 are Pb big basic ionic radius, Ti and Zr small basic ion and respective
anion by oxygen.
The measured t value is calling factor of tolerance and in case of ideal cubic
perovskite is equal with unity.
In case of a reasonable measure, an alignment could be possible because there exists
same allowed directions inside each crystal.
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Figure 1. Piezoelectrics and ferroelectrics ceramic's polarisation process a-depolarisation ceramic b, c –
ceramic in time of polarisation and after this process 6.
2. Determination of material's properties used at the manufacturing of ultrasonic
motors.
For the ultrasonic motors designed and manufactured shown in scientific literature, there has
been determinated a lot of properties of piezoelectrics materials used and also the effects of
temperature against them in function time.
Table 1 Main properties of piezoelectric materials PIC ―soft‖ type
Name
General description
„Soft‖ PZT
PIC15 PIC151 is a modified lead zirconate-lead titanate material with high 600 II
1
permittivity high coupling factor and high piezoelectric charge constant.
This material is the standard material for actuators and suitable for lowpower ultrasonic transducers and low-frequency sound transducers.
PIC25 PIC 255 is a modifiend PZT material with extremely high Curie 200 II
5
temperature, high permittivity, high coupling factor and high carge
constant. The high coupling factor, low mechanical quality factor and
low temperature coefficient make this material particularly suitable for
low-power ultrasonic transducers non-resonant broadband systems, and
for force and acoustic pick-ups.
PIC15 PIC155 is a modification of the PIC 255 material distinguished by high 200 II
5
piezoelectric stress coefficients and lower frequency constants. It is used
in applications where a high g-constant is required, such as in
microphones and vibration pickups with preamps.
Table 2 Main characteristics of piezoelectric materials PIC ―hard‖ type
Name General description
‖Hard‖ PZT
PIC18 PIC181 is a modified lead zirconade–lead titanate material with ar 100 I
1
extremely high mechanical quality factor and a high Curie temperature.
This material is destined for the use in high–power acoustic applications.
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PIC14
1
PIC24
1
PIC 141 is a modified PZT material with a mechanical quality factor and 100 I
a comparatively moderate permittivity. This material is designed for use
in high–power acoustic applications and is also used for pharmaceutical
atomizers.
PIC241 is a PZT ceramic is distinguished by its high mechanical quality 100 I
factor and comparatively high permittivity. Its fields of applications lie in
high–power ultrasonic devices and it is used for piezomotor drives.
Some of these properties for singularity piezoceramics materials PIC 151, PIC 554
and PIC 225, used at the manufacturing of ultrasonic motors, are showed in the followings
diagrams 6.
In figure 2, there is shown the variation of capacity with temperature for
piezoceramics materials PIC151, PIC255 and PIC155 used for manufactured active elements
of some ultrasonic motors.
ΔC/C
100
80
60
40
20
-50
0
-20 0
50
100
150
200
-40
C
ΔfS/fS
Figure 2. The variation of the capacity with temperature for piezoceramics materials PIC151,
PIC255 and PIC155.
-50
6
5
4
3
2
1
0
-1 0
-2
-3
-4
50
100
150
200
C
Figure 3. Resonant frequency's longitudinal oscillation fr, related to temperature for piezoceramics
materials PIC151, PIC255 and PIC155.
In figure 3 there is shown the resonant frequency's longitudinal oscillation fr related to
temperature for piezoceramics materials PIC151, PIC255 and PIC155.
In figure 4 there is shown the variation of factor k31 with temperature for
piezoceramics materials PIC151, PIC255 and PIC155.
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1
0
ΔK31/K31
-50
-1 0
50
100
150
200
-2
-3
-4
-5
-6
-7
C
Figure 4. The variation of factor k31 with temperature for piezoceramics materials PIC151,
PIC255 and PIC155.
3. Conclusions
1. One of any types of ultrasonic motors important elements is the active element,
which depends totally by functional properties, by manufacturing and specially depends by
the mobility of dipole or domain, and in conclusion it depends by the behavior at polarisation
and depolarization.
2. The piezoceramic material's constants can vary during time because of thermal,
mechanical and electrical depolarisation reasons and also by the ageing of material.
3. The case researched by now had been evidenced the advantage of using the
piezoelectric ceramics in manufacturing of ultrasonic motors compared with the use of
magnetostrictive, electrostrictive materials or another type.
4. The piezoceramic active element's oscillation mode is determinated by his
geometries, by his mechanical and supply proprieties and also by the direction of polarization.
5. The advantage of piezoceramics materials used, PIC special type materials, are
characterised by the big value of the coefficients of electromechanical coupling, chemical
stability, relative high temperature of function, also by the possibility of manufacturing in
the most variety forms and possibility choices in any direction for polarization axe.
REFERENCES
1 AMZA, Gh. ş.a. - Ultrasunete de mari energii. Editura Academiei, R. S. R, Bucureşti,
1984.
2 AMZA, Gh. ş.a. - Tratat de tehnologia materialelor. Editura Academiei, Bucureşti, 2003.
[3] A. LANGELLA, C.VISCONTI, Technological characteristics of a new optical sensor for
smart composites. Advanced Composite Materials. Detroit, Michigan, 1991.
[4] ABRAHAM S., TAY, A. Strain concentrations around embedded optical fibers by FEM
and moire Interferometry. Advanced Composite Materials, Detroit, Michigan, 1991.
[5] ACHENBACH, J., FANG, S. Asymptotic analysis of the modes of wave propagation in
solid cylinder. Journal of Acoustics Society, 1970.
[6]. *** Physikinstrumente Company-Catalogue: Designing with piezoelectric transducers:
Nanopositioning Fundamentals, 2005, p. 13.
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PLATYNG OF WEAR RESISTANT SURFACE LAYERS BY THE
METHOD - LASER SINTERING
Lecturer dr.ing. CIOFU Florin, Lecturer dr.ing. NIOATA Alin
University "Constantin Brâncuşi" of Târgu-Jiu, [email protected]
Abstract: The essence of process for production of metal powders by aggregation is the formation and sintering
operations that cause growth and stabilization of the contact surfaces, together with connections interatomic
cohesion between particles.
A body of metal powders is a thermodynamically unstable state due to the smoothness powder, grains
surface roughness, form, degree of hardening in deformed areas, surface defects at grain polycrystalline
networks (vacations, dislocations), etc.
Keywords: powder, alumina, protective atmosphere, grains surface
1.Introduction
In this paper will be presented several studies on deposition of wear resistant layers on
the
surface of pieces of ordinary materials, common, a relatively
new
technology laser sintering.
Experiments similar to those presented in this paper were described in their
previous works, both in terms of the mechanics of obtaining evidence and in terms
of observations and interpretation of results.
Concomitantly, I
watched with interest and practice of professors from other
universities and research centers abroad. The results were analyzed and compared with those
obtained in my studies, being me often of great use.
In his work Bourell D. L, [1] is representative deposits metal-ceramic materials by
laser-sintering. Tolochko N.K, [13] studied deposits in layers, or layers of material deposited
over other layers of different material (with intermediate layer deposition).
Such, this paperwill be presented an experiment in hich we obtained some evidence of
a material
base - OLC 45,
which I deposited
on the surface of lasersintering technology, metal powders of Al2O3 layers in different thicknesses. The physicochemical features upper oxide ceramics are determined by low content or absence
of vitreous phase, something that is a primary goal in ceramic processing.
Aluminum oxide Al2O3 ceramics is the main element and is found in nature as
corundum, which may be colorless or colored differently as: ruby (red), sapphire(blue), topaz
(yellow). Temperature sintering ceramics based on Al2O3 is between 1550oC and 1650oC.
Descent sintering temperature is achieved by introducing the mixture of raw
material composition of mineralized flux, influencing the subsequent processing and product
characteristics, the formation of melts which act as binders between alumina particles [1].
Method deposition of layers of materials with a characteristic usually over a base
material offers many advantages, the most important is economic.
Alumina Al2O3 as high densityand high purity (>99.5%) was the first bioceramic
material widely used in various clinical applications.
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The combination of excellent properties, corrosion resistance, good compatibility,
high wear resistance, outstanding mechanical properties, is used in the following areas:
-maxillofacial reconstruction using Al2O3-based ceramics as bone cavity filling
material;
-various plastic surgery to achieve the alveoli of alumina, hydroxyapatite and
alumina ceramic composites;
-the construction of various medical devices as sensors, electrodes, pacemakers,etc..;
-replacement of bone segments;
-in dental ceramics, aluminum oxide powder is a primary component in dental
porcelain;
-in prosthetic, alumina is used as surface coatings on metal surfaces - as
in
hip,
elbow or shoulder.
2. Experimental study
2.1. The materials used
Deposits were made on flat surfaces of a piece of OLC 45 [2,3]. Rectangular shaped
piece dimensions are: h = 4mm, L = 80mm, l = 50mm. Basic material characteristics are
presented in Tables 1 and 2 [1].
Table 1. The chemical composition of steel OLC45.
Steel
Chemical composition [%]
C
Mn
Si
Pmax
OLC 45
0,42…
0,50…
0,17…
0,040
0,50
0,80
0,37
Annealing
2
HBmax daN/mm
OLC45
235
207
Călire şi
revenire
înaltă
Thicknes
s product
mm
Normalized
Heat
treatment
Tabel 2. Mechanical characteristics of steel OLC45.
Delivery status
Steel
<16
Critical temperatures
Ac1[oC]
Ac3[oC]
725
780
S
max 0,045
Mechanical characteristics
Main areas of
use
Rm
N/mm2
Rp
N/mm2
A5
%
KCU
J/cm2
700…
840
480
14
59
Parts heat
treated, high
mechanical
strength and
toughness
average.
Additional layer is made up of a powder of Al2O3. Pure alumina (> 99.5%) has been
used since the '70s, as material for implants, especially for artificial joints and teeth, due to its
good mechanical and biocompatibility with tissues. Al2O3 powder characteristics are
presented in Table 3 [1].
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Table 3. Characteristics of Al2O3 powder
Physical properties
Density
3,96 [g/cm3]
Constant matrix
4,7591 [Å]
Molecular weight
Module Weibull
101,961 [g/mol]
10
Mechanical properties
Hardness (Vickers)
1365
Microhardness (Vickers)
2085
Tensile strength
300 [MPa]
Elastic modulus
370 [GPa]
Resistance to bending
400 [MPa]
Compressive strength
3000 [MPa]
Thermal properties
Linear expansion
7,4 [μm/(m°C)]
coefficient (250°C)
Linear expansion
8,2 [μm/(m°C)]
coefficient (1000°C)
Thermal conductivity
30 [W/(mK)]
Melting point
2054 °C
Boiling point
3000 °C
Optical properties
Refractive index
1,761
Description
Color
White
Crystalline structure
Rhombohedral
Grain size
15-20 [μm]
2.2. Equipment used
The experiments were run in two stages, purposes to production workshops
Phoenix & CO company Sibiu. Because the first attempts were made without a sintering
environment - a protective atmosphere, parts could not be obtained to provide the relevant
evidence on which to make some measurements
In fact, Figure 1 shows the aspects of such an experiment [1].
Fig. 1. Deposition on the surface of a piece of 4mm
thick material OLC45.
Fig.2. Al2O3 particles (99.5%), sintered by laser
beam on the surface OLC45 (electronic1500x).
Therefore, experiments were repeated, this time in the protective environment of gas
(CO2). Sintering was performed at a temperature of about 1550oC. Laser installation was set
to an output of 200W. Power density was adjusted to 700W/mm2 and diameter laser outbreak
are reduced to 300μm. In micrography (Fig. 2) shows that sintering in the presence of solid
phase, as confirmed by the presence of pores.
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2.3. Sintering mechanisms
A body of metal powders is a thermodynamically unstable state due to the smoothness
powder, grains surface roughness, form, degree of hardening in deformed areas, surface
defects at grain polycrystalline networks (vacations, dislocations), etc. Thermal activation of
this system, by heating for sintering, produces transition of a state nearest equilibrium by
reducing the free surface [6]. Except these phenomena, same time with the sintering it takes
place a process of softening, namely a reduction of the rezistance to deformation of the
cristalline grains from the particles, leading to the viscous flow. To the superficial tension of
the material of the grains it is opposed a weakened rezistance of the crystalline grains on the
contact zones. The value of the superficial tension exceeds the critical tension of flowing –
creep tension, at the respective temperature and determines displacings of the gliding plans,
therefore a mass transport by the flow in the viscid state of the material.
During the sintering, next to the effect of the body contraction, it is produced the
continous reduction of the porosity by the decreasing the dimensions and the form of the
eyepores.
Sintering environment (protective atmosphere) occurs in the processes that occur in
the superficial layers of materials during sintering. Through judicious selection of these media
properties can be obtained so upper and reducing the time and sintering temperature.
Material moves under the influence of surface energy at the convex surface near the
concave surface of the material transport mechanisms. Processes of material transport links
between particles increases thus generating the phenomenon of shrinkage during sintering.
2.4. Specimens optained
There have been four samples: the OLC 45 plates with dimensions h = 4mm,
L =80mm,
l = 50 mm
were deposited Al2O3 powder layer thickness of
0.2 mm, 0.6 mm, 1 mm or 1.2 mm sintered laser beam (fig.3, fig.4, fig.5, fig.6).
Fig.3. Deposition of powder Al2O3 (99,5%)
on the support OLC 45
(thickness deposited h = 0,2 mm, optic 100x)
140
Fig.4. Deposition of powder Al2O3 (99,5%)
on the support OLC 45
(thickness deposited h = 0,6 mm, optic 100x)
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Fig.5. Deposition of powder Al2O3 (99,5%)
on the support OLC 45
(thickness deposited h = 1 mm, optic 100x)
Fig.6. Deposition of powder Al2O3 (99,5%)
on the support OLC 45
(thickness deposited h = 1,2 mm, optic 100x)
4. Conclusions
Performing results of measurements, we can conclude the following:
-The deadline for submitting, near the base material, wear resistance is considerably
higher than the base material itself;
-The modification states that the deposited layer thickness, by increasing its changes,
all with increased resistance to wear;
-Loss of mass in the layers are substantially lower than the basic material submitted,
proving the wear resistance of alumina;
-Are higher mass-loss limit for submission decreasing thickness layer, proving that a
thicker layer provides better wear resistance;
References
[1] B o c h , P . , N i e p c e , J . - C . , C e r a m i c M a t e r i a l s - Processes, Properties and
Applications,ISTELtd, 2007, pp. 199-209;
[2] Bourell D. L, H. L. Marcus, J. W. Barlow, and J. J. Beaman, - Selective laser sintering of
metals and ceramics, Int. J. Powder. Met., 28, No. 4, 369-381 (1992)
[3] Brinkman H.J., F. Zupanic, J. Duszczyk, L. Katgerman; - Production of Al-Ti-C grain
refiner alloys by reactive synthesis of elemental powders: Part I. Reactive synthesis and
characterization of alloys. Journal of Materials Research, 15/12 (2000) 2620-2627. ISSN:
0884-2914;
[4] Brinkman H.J., F. Zupanic, J. Duszczyk, L. Katgerman; - Production of Al-Ti-C grain
refiner alloys by reactive synthesis of elemental powders: Part II. Grain refining performance
of alloys and secondary processing. Journal of Materials Research, 15/12 (2000) 2628-2635;
ISSN: 0884-2914;
[5] Ciofu Florin – Asupra aplicării laserului ca sursă energetică în progesul de
agregare/depunere a unor pulberi metalice, Teza de doctorat, Sibiu, 2007
[6] Ciofu Florin - Experimental studies on the laser depositions of the Al2O3 powder on the
plane surfaces, Annals of the University of Oradea, Fascicle of Management and
Technological Engineering,IMT Oradea 2009,CNCSIS"Clasa B+"
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[7] Ciofu Florin - Experimental studies on the laser deposits with Al2O3 powder on cylindric
surfaces, Annals of the University of Oradea, Fascicle of Management and Technological
Engineering, IMT Oradea 2009, CNCSIS "Cl. B+"
[8] Ciofu Florin - Experimental research into increasing materials properties by means
depositions. 1.Plane surfaces, Scientific Conference 13th edition, November 13-14, 2009, TgJiu, ISSN 1842-4856, pag.91-100
[9] Tolochko N. K., S. E. Mozzharov, N. V. Sobolenko, et al., - ―Laser selective layer-bylayer sintering of powders: problems and perspectives,‖ Poroshk. Metall., Nos. 3-4, 32-27
(1995).
[10] Isarie C., Nemeş T., Ciofu Florin, Popescu F., - Properties and characteristics of parts
obtained by laser sintering of titanium powder mixtures., 11th International Research/Expert
Conference ‖Trends in the Development of Machinery and Associated Technology‖ TMT
2007, Hammamet, Tunisia, 5-9 September, 2007.
[11] Liu Z., Kovacevic R., Temperature Control Based on 3-D Thermal Finite Element
Modeling of Laser Direct Metal Deposition, Solid Freeform Fabrication Symposium, August
2-4, Austin-Texas, SUA 2004;
[12] Ragulya A. V, - ―Selective laser sintering of multilayer oxide ceramics,‖ Functional
Mat., 8, No. 1, 162-166 (2001).
[13] Tolochko N. K., S. E. Mozzharov, N. V. Sobolenko, et al., - ―Laser selective layer-bylayer sintering of powders: problems and perspectives,‖ Poroshk. Metall., Nos. 3-4, 32-27
(1995).
[14] Tolochko N. K., I. A. Yadroitsev, A. F. Il‘yushchenko, et al., ―Principle possibilities of
preparing articles for micromechanics by laser sintering of metal micro- and nanopowders,‖
in: Nanostructural Materials: Preparation and Properties [in Russian], Minsk (2000).
[15] Tolochko N. K. , Tu. A. Sheinok, T. Laoui, et al., ―Laser processing of fine powders
using powder microfeeding and micro-shaping techniques,‖ Proc. EUROMAT 2001 Conf.
(10-14 June, 2001, Rimini, Italy), Rimini (2001).
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ALUMINISATION THERMOCHEMICAL TREATMENT APPLIED
TO WEAR RESISTANT COATINGS
Lecturer dr.ing. CIOFU Florin, Lecturer dr.ing. STĂNCIOIU Alin
University "Constantin Brâncuşi" of Târgu-Jiu, [email protected]
Abstract: Aluminisation process is particularly widespread the process to increase wear resistance, oxidation
resistance, heat-resistant alloysto replace expensive heat resistant to 800oC-1000oC, with cheaper materials.
Keywords: powder, aluminium, laser-sintering
1.Introduction
In a previous paper „Platyng of wear resistant surface layers by the method - laser
sintering‖ I presented some pieces of a base material from OLC 45, that were made by
process laser-sintering layer of Al2O3 powder. In this paper we apply these parts heat
treatment aluminisation in order to observe changes in structure and physico-mechanical
properties obtained.
By aluminisation (alitare or hardening aluminum) surface enrichment is achieved by
diffusion of aluminum products made of ferrous alloys, to increase resistance to oxidation at
high temperatures (800o-900oC) in solid medium, liquid or gaseous, diffusion layer thickness
reaching value 0,02 – 1,2mm.
Speed of diffusion of aluminum in the alloys of iron with carbon is influenced by their
content of carbon and alloying elements is the lower, the higer their proportion is higher. For
this reason, aluminisation applies in particular products made of carbon and low alloy steels,
with low carbon content and less of the average content of carbon steels or cast iron.
Aluminisation process is particularly the process of increasing the wear resistance,
oxidation resistance to hot, to replace refractory alloys expensive, heat resistance 800 o1000oC, with cheaper materials.
2.Experimental study
2.1. The material investigated. Experimental study
Based on unfavorable influence on the deformability of aluminum and steel hardening,
will try aluminisation heat treatment of samples of OLC 45 that were previously filed by
laser-sintering technology, additional layers consisting of Al2O3.
For the experimental, were used specimens obtained in the work „Wear resistant
coatings obtained by the method - laser sintering‖.
Aluminum surface enrichment of samples was done by keeping the different times al
temperatures 820oC şi 860oC in a bath of molten aluminum, containing 90% aluminum (Al
99,7) and 10% submitted filings to protect evidence them against corrosion.
To avoid oxidation of aluminum melt, on its surface to put a layer of flux with explicit
composition in table 1.
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Table 1- Flux coating composition.
Composition
NaCl
[%]
40
KCl
40
Na3AlF6
10
AlF3
10
For making the experiment using a ceramic melting pot, which was filled with 900g
aluminum and 100g iron powder, so that after melting the fullness load of the melting pot was
75%. Melting pot was introduced into the furnace and was heates to 800oC, so that aluminum
is melted, covering iron powder. Immediately after the melting of aluminum metal bath was
covered a thick layer of flux around 10mm.
Then, molten metal in the form described above, heated furter to temperatures 820oC
respectively 860oC. At this point, samples were placed on all melt bath and maintained for a
period of time according to a schedule previously (table 2).
Table 2- Regime aluminisation
Sample
1
2
3
4
T[oC]
820
820
860
860
Regime aluminisation
Hold time [min]
15
15
20
20
Cooling medium
oil
oil
oil
oil
2.2. Structure and properties of aluminized layer
Aluminized layer structure, nature, sequence and structural constituents of different
morphology, are determined directly from concentration and distribution of aluminum in the
diffusion layer. Aluminized layer constituents monophasic domains corresponding equilibrum
diagram of iron-aluminum. The concentration and distribution of aluminum in the surface
layer is due to both process and technological parameters used aluminisation selected
(temperature and duration of maintenance), and steel type submitted aluminization.
Sample 1- Plate of OLC 45 with dimension h=4mm, L=80mm, l=50mm that have
submitted a layer of Al2O3 with thick 0,2mm. After application of termochemical treatment
aluminisation in the conditions described above, resulting microstructure shown in figure 1.
In the sample microstructure distinguished four succesive zone:
1- outer layer on the sample surface machanically joined during extraction in the
bathroom, with a thickness of about 0,15mm and an irregular interface as a result of
interdifusion processes between the two layers ;
2- between the top layer consist of aluminum + phase θ and layer deposited there is a
thin border around 0,02mm, strongly attacked by reactive.
3- layer made of Al2O3, weak attack, is in alloy of aluminum with alumina, thick
0,2mm;
4- basic mass of the sample, spoon showing fine structure, being attacked intensely
reactive;
Sample 2 - Palte of OLC 45 with dimension h=4mm, L=80mm, l=50mm that have
submitted a layer of Al2O3 with thick 0,6mm. After application of termochemical treatment
aluminisation in the conditions described above, resulting microstructure shown in figure 2.
In the sample microstructure distinguished four succesive zone:
1- outer layer adhered on the sample surface during mechanical extraction in the
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bathroom, with a thickness of about 0,05mm. Thickness smaller than for sample 1 is caused
by speed extraction of the sample in the melting pot;
2- thin boundary layer around 0,01mm, consists of phase θ;
3- layer made of Al2O3, thicker than for a sample 1 about 0,6mm, presenting to play a
sinuous contours;
4- basic mass of the sample, showing spoon fine structure, being attacked intensely by
the reactive;
Fig.1. Microstructure of sample 1
(thickness deposited h = 0,2 mm, optic 100x)
Fig.2. Microstructure of sample 2
(thickness deposited h = 0,6 mm, optic 100x)
Fig.3. Microstructure of sample 3
(thickness deposited h = 1 mm, optic 100x)
Fig.4. Microstructure of sample 4
(thickness deposited h = 1,2 mm, optic 100x)
Sample 3 – Plate of OLC 45 with dimension h=4mm, L=80mm, l=50mm that have
submitted a layer of Al2O3 with thick 1mm. After application of termochemical treatment
aluminisation in the conditions described above, resulting microstructure shown in figure 3.
In the sample microstructure distinguished four succesive zone:
1- outer layer adhered on the sample surface during mechanical extraction in the
bathroom, with a thickness of about 0,1mm consists of aluminum and phase θ. Medium
thickness 0,1mm indicates a low extraction rate of the sample in the melting pot;
2- the thin boundary layer about 0,01mm, consists of phase θ;
3- layer deposited of Al2O3 thick 1mm, shown into play also has a sinuous shape but
more subdued than in sample entered the bathroom located at a temperature of 820oC;
4- basic mass of the sample, showing spoon fine structure, being attacked intensely
reactive;
Sample 4 - Plate of OLC 45 with dimension h=4mm, L=80mm, l=50mm that have
submitted a layer of Al2O3 with thick 1,2mm. After application of termochemical treatment
aluminisation in the conditions described above, resulting microstructure shown in figure 3.
In the sample microstructure distinguished four succesive zone:
1- outer layer adhered on the sample surface during mechanical extraction in the
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bathroom, with a thickness of about 0,12mm consists of aluminum and phase θ. Medium
thickness 0,12mm indicates a low extraction rate of the sample in the melting pot;
2- the thin boundary layer about 0,02mm, consists of phase θ;
3- layer deposited of Al2O3 thick 1,2mm, shown into play also has a sinuous shape;
4- basic mass of the sample, showing spoon fine structure, being attacked intensely
reactive;
3. Conclusions
From the examination microstructures shown in figures 1-4 allows the following
conclusions:
-as expected, after aluminisation, in the section samples resulted four successive zones,
characteristic on the process of thermochemical treatment used;
-on the surface has been obtained one layer mechanically joined during the extraction from
bath of aluminum. Interface with the adjacent layer is in the all cases irregular, due to
interdifusion processes that occur during aluminisation between molten metal and steel
sample;
-the first layer thickness was variable from sample to sample, depending on the speed sample
extraction of the melt bath;
-in the outer layer, optical microscope examination revealed the fact that not only is the
aluminum phase θ (FeAl3);
-between aluminum layer + phase θ formed and diffusion layer, observed presence of a thin
0,01-0,02mm border, strongly attacked by reactive;
-the third layer is the diffusion of aluminum in the alumina layer, rich in aluminum;
-the fourth layer (base layer) not substantially altered the structure;
References
[1] Brinkman H.J., F. Zupanic, J. Duszczyk, L. Katgerman; - Production of Al-Ti-C grain
refiner alloys by reactive synthesis of elemental powders: Part I. Reactive synthesis and
characterization of alloys. Journal of Materials Research, 15/12 (2000) 2620-2627. ISSN:
0884-2914;
[2] Brinkman H.J., F. Zupanic, J. Duszczyk, L. Katgerman; - Production of Al-Ti-C grain
refiner alloys by reactive synthesis of elemental powders: Part II. Grain refining performance
of alloys and secondary processing. Journal of Materials Research, 15/12 (2000) 2628-2635;
ISSN: 0884-2914;
[3] Ciofu Florin – Asupra aplicării laserului ca sursă energetică în progesul de
agregare/depunere a unor pulberi metalice, Teza de doctorat, Sibiu, 2007
146
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STUDIES REGARDING THE CALCULATION OF SLIDING FIT
DIMENSION CHAIN
S.l.dr.ing. Constanța Rădulescu
Prof.univ.dr.ing. Liviu Marius Cîrțînă
Faculty of Engineering―Constantin Brâncuși‖ University of Tg-Jiu,
[email protected]; [email protected]
Abstract: This paper presents a case study regarding the determination of a dimension chain consisting in the
case of a sliding fit of a guide column and a bushing guide of a die. It also presents the distribution of the chain
elements tolerances values, their standard deviation and output probabilities values for the studied values. Data
processing was made with a PQRS statistic program.
Key words: dimension chain, tolerance, standard deviation
1.INTRODUCTION
The allocation of a part dimensional tolerances is a special matter because it influences
both the good operation of the assembly and its execution cost. When we refer to the
production cost of a part, we have to consider several determining factors, that is: the
production process, material, thermal and chemical treatments, part size, part dimensional
tolerances, etc.
When we refer only to the size of dimensional tolerances of a revolution part, they are
rendered in tables in the specialized literature (the case of shafts and bores). Even if these
values have been determined at industrial scale, they are not the optimal ones.
The specialized literatures presents charts where the value of the execution index cost
increases along with the decreases of the part execution class (fig1). This is normal because
we know that allocating restricted tolerances requires more complex processing operations,
and implicitly leads to the increase of production costs.
Fig.1. Production cost index depending on the precision class.
In order to see the importance of the part execution tolerance, the case of shafts can be
discussed. In general, the specialized literature presents us simpler cases when the shaft and
bore form a clearance fit. But we have to study the cases of tight fits and medium fits.
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2.DETERMINING THE CALCULATION OF DIMENSION CHAINS FOR
A SLIDING FIT
It is known that the tolerances of parts dimensions presented in the execution drawing
have to coincide with the real tolerances determined as a result of measurements made. It is
always desired that the measured dimension, and implicitly its deviations be within the ranges
of the provided tolerance field, in this case we speak about permissible deviations or
conformities. But there are cases when the measured dimension is not in the tolerance field
and then we are speaking of non-permissible deviations or non-conformities, and therefore
parts are rejected (fig.2).
If we consider a normal distribution of the measured dimensions of a sample for
determining parts non-conformities we can be in one of the following cases:
 If measured values have values very close to the provided limit values (upper, lower)
there
is a high probability of accepting these non-conformities parts P≥90%. In this case, these nonconformities have the name of AQL acceptable quality level;
 If measured values are far from the limiting values, there is a small possibility for
accepting
these non-conformities parts, P<10%. In this case, these non-conformities have the name of
LQ quality limit LQ.
Starting from this idea, we will study the case of the dimension chain formed in a fit. It is
known that the dimension chain of a fit generally consists of three elements: increasing
element (bore), reducing element (shaft) and closing element.
Fig.2. Tolerance field areas
Fig.3. The fit between a guide column and a
bushing guide of a die
This paper will study the case of a sliding fit of a guide system. The guide system
consists of a guide bushing and a guide column of a die. The guide column has a cylindrical
tail and a support collar. Along with the guide bushing it forms a sliding fit H7/h6. The fit
dimension will be Ø50 H7/h6.
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For the guide column:
0
Ø50 h6( 0,016 ), therefore: Li=49,984mm, Lm=49,992mm, Ls=50,000mm and Td=0,016mm.
For the guide bushing:
0,025
Ø50 H7( 0
), therefore: LI=50,000mm, LM=50,0125mm, LS=50,025mm and Td=0,025mm
Fig.4. Initial values distribution.
In order to see the importance of the part execution tolerance, we can discuss the case
of fits. In general, the specialized literature presents us simpler cases when the shaft and bore
form a clearance bore. We have to study the cases of tight fits and intermediary fits when
dimensions overlap.
It is known that the tolerances of a part dimensions, presented on the execution drawing have
to coincide with the real tolerances determined as a result of the measurements made. We
always want that the measured dimension be within the ranges of the tolerance field.
In this case, the dimension chain consists of three elements: increasing element and
decreasing element (rated dimensions of the column and bushing) and closing elements. The
upper and lower values of the closing element are the value of minimal and maximal
clearance of the sliding fit discussed. In this case we will get:
J min  Dmin  d max  50, 000  50, 000  0, 000mm
J min  Dmax  d min  TD  Td  0, 025  0, 0, 016  0, 041mm
Outputs probability for the minimal and maximal dimensions of the shaft and bore are
determined as follows:
- For the bore:
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At the upper limit
x

x
5
0
,
0
2
5

5
0
,
0
1
2
5
S
M
u




3
S
,
0
,
0
0
4
1
6
1
the specialized literature chooses the values of 0,00135, which means that p=0,135%;
-

At the lower limit:
xx
0

5
0
,
0
1
2
5
I
M5
u



3
I
,
0
,
0
0
4
1
6
1
the specialized literature chooses the values of 0,00135, which means that p=0,135%;
-

For the shaft:
- At the upper limit
x

x
5
0
,
0
0
0

4
9
,
9
9
2
s
m
u



3
,
0
7
s
,
0
,
0
0
2
6
2
the specialized literature chooses the values of 0,00107, which means that p=0,107%;
-

At the lower limit:
x

x
9
,
9
8
4

4
9
,
9
9
2
i
i 4
u



3
,
0
7
i
,
0
,
0
0
2
6
2
the specialized literature chooses the values of 0,00107, which means that p=0,107%.
-

In this case, for the closing element between the shaft and bore, which have the rated
dimension equal to 0, the standard medium deviation is calculated using the relation:






0
,
0
0
4
1
6

0
,
0
0
2
6

0
,
0
0
4
9
2 2
1 2
2
2
The reduction factor for normal distribution will be:
3

0
,
0
0
4
9
r

0
,
3
5
8
3
D
N
0
,
0
2
5

0
,
0
1
6
If we consider the reduction factor and we consider the same value of the square average
deviation for the two elements of the dimension chain, then the distribution curves with their
related values are presented in figure 5.
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Fig.5. Final values distribution.
Outputs probability for the minimal and maximal dimensions of the shaft and bore are
determined as follows:
- For the bore:
- At the upper limit
x

x
5
0
,
0
2
7
2

5
0
,
0
1
2
5
S
M
u




2
,
5
5
S
,
0
,
0
0
4
9
1
the specialized literature chooses the values of 0,00539 which means that p=0,539%;
- At the lower limit:
x

x
4
9
,
9
9
7
8

5
0
,
0
1
2
5
I
M
u




2
,
5
5
I
,
0
,
0
0
4
9
1
the specialized literature chooses the values of 0,00539, which means that p=0,539%;
- For the shaft:
- At the upper limit
x

x
5
0
,
0
0
0

4
9
,
9
9
2
s
m
u




1
,
6
3
2
s
,
0
,
0
0
4
9
2
the specialized literature chooses the values 0,00515, which means that p=0,515%;
- At the lower limit:
x

x
9
,
9
8
4

4
9
,
9
9
2
i
i 4
u




1
,
6
3
2
i
,
0
,
0
0
4
9
2
the specialized literature chooses the values of 0,00515, which means that p=0, 515%.
In this case, for the closing element between the shaft and the bore, which has the
rated dimension 0, the standard medium deviation is calculated using the relation:




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

2


2

0
,
0
0
4
90

,
0
0
6
9
2
2
The deviations of this element are therefore determined:
ls=lm +3σ=0,0412mm
li=lm -3σ=-0,0002mm
after determining all the elements and their related deviations, the related conclusions
can be drawn.
3.CONCLUSIONS
As we can see in fig.3, values spreading, both for shafts and for bores, is made
according to a normal distribution with the standard deviation for bores σ=0,004126 and for
the shaft σ=0,0026. In this case, the closing element of the dimension chain has a normal
distribution curve, with the standard deviation of σ=0,0049, and the value of the tolerance
field middle point of the closing element is lm=0,0205mm.
All the three elements of the dimension chain are within the admitting limits. The
output probabilities percentage is very small, which means that the siding fit is complied with,
and the percentage of non-conformities is also very small.
In fig. 4, we notice that values spreading is made according to a normal distribution
with the standard deviation σ=0,0049 both for bores and for shafts. In this case, the closing
element of the dimension chain has a normal distribution chain, with a standard deviation
σ=0,0069, and the value of the tolerance field middle point of the closing element is
lm=0,0205mm. In this case all the three elements of the dimension chain regarding values
spreading are not within the admitting limits. Outputs probability percentage is very low in
this case as well, because the difference between the calculated limitations and the real
limitations is very small to the order of thousands. Nonetheless, outputs probability for this
case increases and there is the possibility that a sliding fit transform into tight fit.
REFERENCES.
Dumitraș, C. – Dies and matrices made of modulated elements, Technical Press,
Bucharest, 1980.
2. Liviu-Marius Cirtina, Constanta
Radulescu - Effects of Measuring Uncertainty over the Quality of the Products - WSEAS
International Conference on MANUFACTURING ENGINEERING, QUALITY and
PRODUCTION SYSTEMS, Transilvania University of Brasov, Romania, April 11-13, 2011
3. Liviu Marius CÎRŢÎNĂ, Constanţa
RĂDULESCU- Researches regarding the determination and optimization of dimension chains
in the case of the direct problem, Reliability and Durability Magazine, Supplement, no 1/
2010, pag. 85, ―Academica Brâncuşi‖ Press, Târgu Jiu, ISSN 1844 – 640X.
4. Gunter Kirschling, - Quality assurance
and tolerance, Springer-Verlag Berlin Heidelberg 1991.
5. http://members.home.nl/sytse.knypstra/PQRS/
1.
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CONTRIBUTIONS TO THE DEVELOPMENT OF A MODEL OF ECO
TECHNOLOGIC ORGANIZATION
Prof. univ. dr. ing. Dan DOBROTĂ, ‖Constantin Brâncusi‖ University of Târgu - Jiu,
Romania, [email protected]
Prof. univ. dr. ing. Gheorghe AMZA, Polytechnic University of Bucharest Romania,
[email protected]
Abstract: The paper present a series of contributions to the development of a model of eco technologic
organization. Managers of various organizations generally recognized the need for change, as a
way to cope with competitive pressures, but many do not understand how the change should
be implemented. The key to success is to integrate employees, their roles and responsibilities
within the organization in a structure of processes. A process-based approach and starting
with the declaration of vision and mission, analyzing critical success factors and identifying
the basic processes, it is the most effective way of employment of staff in the process of
change In these conditions paper addresses notions of implementation of the change in the
industrial organizations: organizational change process, consequences of ignoring the change, internal and
external factors of change, actions needing change.
Keyworks: organization, model, eco technologic, implementation.
1. INTRODUCTION
Each organization has its own specific type of organization and functioning and in this
regard, it is difficult to recommend a common methodology, applicable anywhere, anytime
and whose success is always guaranteed. Although consultants often have their own
methodologies, sometimes quite performing based on a rich work experience, however, it
cannot be said that there is only one way to succeed. The following we will clarify some ideas
and instructions to be used by those who wish to implement or maintain such a system.
2. IMPLEMENTATION MODEL OF ECO TECHNOLOGIC ORGANIZATION
2.1. Initiating implementation model of eco technologic organization
The organizations held a series of changes, some are small scale, affecting an individual
or small group of individuals, such as small changes in work organization at a job, others are
large scale, affecting the overall organization her or its major areas, such as the assimilation of
a new product or introducing a new management system.
Schematically, the changing process appears as in figure 1. An organization must be
aware of market pressures, and develop appropriate strategies to win customers on the basis of
existent competitiveness criteria existent in the market at that time. In reality, market
competitiveness criteria lead the market. Organization cannot change these criteria and the
environment that creates external pressures will not change. Therefore, change must come
from the organization. Figure 2 illustrates the consequences resulting from ignoring the
current market forces and avoiding changing actions.
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There are countless examples of organizations that have paid a lot for ignoring the
changes in market conditions hesitating or refusing to adapt to these changes.
The changes are real changes that apply to any part of the organization: plans and
activity programs, the scope of the management, machinery and equipment, equipment,
organizational structure, the people themselves etc.
Figure 1. Organizational change process
Figure 2. Consequences of ignoring the change
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Figure 3. Internal and external factors of change
Figure 3 represents the schemes of internal and external factors that may cause
changes in an organization. The external factors of change arise from external organizational
environment factors: general and specific (figure 1 and figure 2)
2.2. Awareness of the need to implement environmental management
Managers of various organizations generally recognized the need for change, as a way to
cope with competitive pressures, but many do not understand how the change should be
implemented. The key to success is to integrate employees, their roles and responsibilities
within the organization in a structure of processes. A process-based approach and starting
with the declaration of vision and mission, analyzing critical success factors and identifying
the basic processes, it is the most effective way of employment of staff in the process of
change (table 1).
Senior management should begin developing the new process-oriented structures by
commitment to all levels by observing certain stages. The starting point should be an
overview of the organization and the changes requested by the management team. By carrying
out this diagnostic analysis on the imposed changes, on existing problems, and on the areas
for improvement, can get an initial commitment, vital to begin the transformation process is
obtained.
The basic processes describe what it is done or what should be done so that the
organization achieves success factors. The first step in understanding the basic processes is to
identify an architectural network of processes with the same order of importance (figure 4).
Once the basic processes are defined, it is necessary for the new structure of processes
objectives, targets and performance indicators to be set. The decomposition into subprocesses, activities and tasks is also necessary. An insight into how to the structure of
processes should be carried out is presented in figure 5. Assignments are made by individuals.
The employee must understand the task and his position in the hierarchy of processes.
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Table 1. Actions needing change
Values
Stakeholders‘ attitude towards
environmental performance.
Team work and cooperation
Internalization of the clientsupplier relationship
Leading all the indicators
depending on the degree of
satisfaction of stakeholders.
Primacy of long-term
improvements to rapid
improvements.
Facts and data are preferred to
suspicions and assumptions.
Necessary actions
Reporting results of studies by stakeholders to all
employees; including their satisfaction degree as the key
element for the environmental plan; individual assessing
and rewarding for an exceptional service.
Extensive use of teams to improve quality; reward of
team members according to system of assessment of
special activities.
Using environment quality management at compartment
level; encouraging interaction between compartments.
The communication of this concept to all employees;
meeting stakeholders‘ objectives represent the top
objectives revealing performances of the organization.
Teams to supervise the resolution of factual issues;
rejecting quick solutions that are not supported by data.
Preparing teams to solve problems based on facts;
supporting management teams for the correct diagnosis
based on objective data.
Focus on finding solutions, not
Award those employees who find new problems and
mistakes.
work to solve them.
Total involvement of employees Follow closely the employees involved; relief efforts to
achieve quality and environmental performances;
employees‘ involvement award in the assessment of
organization‘s culture.
Approach the environmental
Structure of quality system must be integrated into the
quality in the context of
existing one; setting targets and long term plans for
organization.
environmental quality; the approach in the field of the
environment is a new road to be followed.
Guideline for environmental
Recruitment and training of appropriate personnel;
quality is an intensive process.
popularize environmental quality policy in the domain of
environmental quality in promoting a new attitude of
staff; training, assessment, promotion and reward staff
with honors in environmental quality domain.
Promoting a spirit of commitment Full involvement of senior management; availability of
to the environment
necessary resources; patience and perseverance in action;
joining local, national and international organizations
having as objective environmental quality.
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Figure 4. Architecture of processes
Figure 5. Identify main processes and their decomposition
3. CONCLUSIONS.
Sustainable development of eco technologic organization cannot be achieved only through
the efforts of the organization, but it requires the participation of all sectors of society.
Government has an important role to play, through laws, regulations, taxation systems and
other measures. The main activities that the Government could perform to management an
eco technologic organization on a sustainable basis are:
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- use the command and control regulations and economic incentives to force industry to
internalize the cost of environmental depreciation, making the polluter (and ultimately the
consumer) pay;
- develop plans and adopts policies to encourage eco technologic organizations to use
environmental factors and natural resources adequately without adversely affecting
productivity;
- conducting or sponsoring research in the environmental field;
- collection and dissemination of significant data material relating to emissions of
pollutants and their effects on human health and the environment, in order to create public
awareness of problems and a request for environmental non hazardous products and services;
- participation in international agreements to reduce pollution, causing cross border
effects.
REFERENCES
1. Amza, Gh., - Eco technology and sustainable development, publisher Printech, Bucharest,
2009.
2.Amza, Gh., Pîrvulescu Mihaela- Achieving sustainable development of a mathematical
model of manufacturing organization eco technology welded construction, TQSD, Bucharest,
2008
3. Gore, Al., Earth in the Balance. Ecology and the Human Spirit, Penquin Books, U.S.A.,
1993.
4. Hart, S.L., Greening, B., - ―Strategies for a Sustainable World", Harvard Business Review
on Business and the Environment, Cambridge: Harvard University Press, p. 108, 2000.
5. Oprean, C., Bucur, A., Vanu, A., „A mathematical model of the innovation indicator"
Balkan Region Conference on Engineering and Business Education & International
Conference on Engineering and Business Education, Sibiu, Romania. 15-17 October,
publishing Lucian Blaga Univesrsity of Sibiu, 2009.
6. Oprean, C., Vanu, A.,‖Leadership and organizational wellness‖, Review of Management
and Economical Engineering, Cluj-Napoca, Romania, volume 8. No.2 (32), 2009.
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FRACTURE FEATURES OF METAL BINDING
WHEN DIAMOND-SPARK GRINDING
Yury GUTSALENKO
National Technical University ―Kharkov Polytechnic Institute‖, Ukraine
Senior Staff Scientist
[email protected]
Abstract: The hypothesis of the influence of binding energy of metal on the processes of destruction and mass
transfer at high-speed machining is considered. Some nonconventional processes of cleaning of intergranularity
spaces from waste products at diamond-spark grinding are explained, the approach to assessment of metal
resistance in these processes is proposed and eo ipso modern conception of processes in chip formation zone
under condition of electric discharge effect is supplemented.
Keywords: high-speed diamond-spark grinding, binding energy of metal, explosive sublimation
1. INTRODUCTION
The most known implementation of abrasive machining accompanied by introduction of
additional energy of electric discharges in cutting area is the process of diamond-spark
grinding developed at the Kharkov Polytechnic Institute [1].
The processes of high-speed machining which enabled with variety of favourable
practical features of new method of combined processing, first of all smaller level of force
intensity became one of the leading tendencies in development of techniques and technologies
of diamond-spark grinding. A typical example can be development of technique and
technologies of internal diamond-spark grinding of hard-to-work materials. In particular, the
Saratov machine-tool plant masters the manufacture of special internal grinding
semiautomatic machine of model 3М227ВЭРФ2 for realization of the technologies of double
high-speed grinding (with high speed of peripheral preparation per grinding wheel).
Investigation of processes dispersion of chip in the area of diamond-spark grinding has
shown that such processes in the electric discharge channel are accompanied by its partial
evaporation with the lowered resistance (high current density), especially at long thin sections
of a cut (chips), characteristic to double high-speed grinding. So it is corroborated
experimentally, including natural modeling, that chips at bridging interelectrode space in
grinding zone, i.e. coming in sliding contact with conductive bond of wheel, can explode
("exploding wire"), and when the peripheral feed of work-piece per grinding wheel becomes
higher and a chip becomes thinner and the interelectrode potential becomes higher, a
probability of such events becomes higher.
Known assessment of erosive resistance of metals by L.S. Palatnik criterion [2] taking
into account the aftereffect of electric discharge on a surface of stationary object of rather
bulky mass when energy of electric discharge is redistributed between evaporation of metal
from a surface of massive object and its heating, is not to the full suitable for real dynamic
conditions in cutting area, including electric "exploding wire" (chip). However this criterion
of a comparative assessment of "pliability" of metals to erosive destruction under the
influence of energy of electric discharge is almost with no alternative recommended and used
for corresponding assessment under condition of diamond-spark grinding [3].
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2. PHYSICAL IDEAS AND PRESENT-DAY EXPERIENCE
From the classical physical positions it is possible to explode metal by means of two
forces: electric or mechanical, influencing only on free electrons.
Experiences of G.Wertheim (1844-1848) to which in the researches of the mechanism of
explosion of metals address M. Marakhtanov (Moscow State Technical University n.a.
N.E. Bauman, Russia) and A.Marakhtanov (Berkeley University of California, the USA) [4]
are indicative in this plan, and according to which already concerning a small electric current
(some tens of amperes) essentially changes characteristics of metals, namely reduces their
rupture strength, and the module of elasticity of metals considerably decreases. It, in
particular, argues in favour of electric current in cutting area from the positions of facilitation
of mass microcutting of surface to-be-machined by abrasive grains of wheel at diamond-spark
grinding.
М. and A. Marakhtanovs have achieved the explosion of the thin metal films of tungsten
and aluminum of the thickness up to 45 nm, i.e. in some atomic layers, and in so thin layer
metal was well cooled by air and heated not up to 180 ºС. It should be noted that to a certain
extent these tests can be considered as an analog of real processes in thin chips, bridging an
interelectrode gap at diamond-spark grinding with cooling. With increase in current density to
very large values, of the order of 1 GA/m2, the electron stream due to quantum processes in a
crystal lattice turns to a wave packet, i.e. current strength in various places of conductor
becomes various, and metal heats up irregularly by electrons grouped in a wave, with a
difference in temperature on a wave crest and in node of wave by several times after that for
some microseconds the explosion of hard metal follows, passing a liquid state (similarly to
explosive evaporation of metal with formation of an erosive trace (a crater) in a point of the
channel of electric discharge of enough high capacity). At current strength of the order of
100 A (corresponds to the characteristic of the commercial wide-range pulse-generators
used for power-supply of electrical discharge processes in the area of diamond-spark
grinding) the current density of the order of 1 GA/m2, corresponding to described by
М. and A. Marakhtanovs explosion of particles equilibrium in metal crystals of
aluminum and tungsten, is observed at its advancing through a conductor of section of the
order of 0,1 mm2, and this value takes in the sizes of sections of a cut (chip),
characteristic to conventional grinding processes (finishing), especially with thin cross sections of cut. Hence we are challenged to optimize fully chip formation (contr ol of
mechanical modes of processing and characteristics of grinding wheels) and electrical
discharge processes (control of electric modes of processing), focused on non conventional processes of cleaning of intergranular spaces from processing products at
diamond-spark grinding. Speed v of body movement before impact, atomic weight А of
metal of which it consists, kinetic energy W ≈ 10-8Av2/2 (in electronvolts) of its every atom,
corresponding to speed of movement, energy ε of c oonnection of particles in metal and their
relation α ≈ W/ε are the signs which determine whether the metal will explode or not.
It follows from this that in order to the metal object explodes on impact with hard
barrier, it is necessary to increase its speed and to choose for it metal with maximum atomic
weight and minimum energy of connection. M.Ja.Fuks et. al. [3] state a fact that "energy of
connection in a lattice decreases in the same sequence as for erosion resistance of metals (W,
Mo, Ni, Fe, Co, Cu, Ag, Al, Zn, Pb, Cd, Sn, Bi)". Here it should be noted that for the listed
metals energy of connection in a lattice as it follows from table 1, decreases nevertheless in a
bit different sequence (W, Mo, Co, Ni, Fe, Al, Cu, Sn, Ag, Bi, Pb, Zn, Cd).
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Table 1: Atomic characteristics of some metals: mass (А) and energy of connection (ε).
Ratio of energies: kinetic and connection (α(v=1) = wk(v=1) /ε) at unit speed of motion (v=1m/s). Speeds of
monometallic bodies, keeping some prescribed ratio of energy
Parameter
Metal
Pb
Bi
Cd
Zn
Sn
Ag
W
Cu
Fe
Mo
Ni
Co
Al
v, m/s
Ax1027, kg
εx1021, J
α(v=1) x106
344,1
347,0
186,6
108,6
197,1
179,1
305,4
105,5
92,7
159,3
97,5
97,9
44,8
324
329
185
216
502
473
1527
531
565
1094
703
706
538
0,531
0,528
0,504
0,252
0,196
0,189
0,1
0,099
0,082
0,073
0,069
0,069
0,042
α = 0,1
α = 0,5
α = 1,0
434
435
445
630
714
727
1000
1003
1104
1172
1201
1201
1550
970
973
996
1409
1596
1625
2236
2243
2469
2621
2686
2686
3465
1372
1377
1409
1993
2257
2298
3162
3171
3491
3707
3798
3799
4901
Atomic properties of metals in table 1 are presented according to [5]. When there are no
data on value of specific sublimation heat ΔHsubl (parameter ε in table 1), but there is an
information on values of specific heat of fusion ΔHfus and evaporation ΔHevap then to
determine
ΔHsubl
one
can
use
the
dependence
ΔHsubl = ΔHfus+ ΔHevap as enthalpy of sublimation is spent at sublimation, and enthalpy is
invariable function [6].
It follows from table 1 that ability to explosion of the metals considered in it decreases in
the following sequence: Pb, Bi, Cd, Zn, Sn, Ag, W, Cu, Fe, Mo, Ni, Co, Al.
3. PECULIARITIES OF HIGH SPEED MACHINING
In the processes of abrasive machining where potential readiness of metals to explode is
worth to use in local microvolumes of intergranular spaces, increase in speed of product tobe-machined in the technologies of double high-speed grinding is one of the factors
favourable for effective use of this readiness at introduction of additional energy of electric
discharges. Another factor, also mechanical one, is increase in speed of processing surface
(grinding wheel). Discharge processes in grinding area, in addition to electric effects, are
accompanied with shock action too which speed is rather great. On various, but almost the
same in the order of sizes, assessment given as an example by A.L.Livshits and Ju.S.Volkov
[7], these speeds reach several hundred meters per second, up to 500-1000 m/s.
The specified values, in particular, are reached the observable speeds of scattering of
particles from erosive pit on surface of the object subjected to pulse discharge influence. In
processes of diamond-spark grinding, wheel bond is such basic object. On the other hand, it is
possible to consider action of front of shock wave capturing microvolumes of bond in point of
the channel of discharge with their subsequent explosive evaporation as direct effect of
electric discharge action on bond of a fast-moving working surface of wheel.
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4. DISCUSSION AND CONCLUSION
The approach under consideration explains well-established conception on comparative
erosion resistance of metal bonds of various grades properly. So, for example, it is known that
among two metal bonds, the most used at manufacturing of diamond grinding wheel, namely
brand М1-01 (copper- aluminium-zinc) and М2-01 (copper-tin) [8], the latter is more erosionresistant. From the considered positions it is possible to explain it by the fact that except
copper its structure includes tin, and on readiness for explosive processes as it follows from
table 1, this metal is worse a little than zinc (by 22 %), but considerably exceeds aluminum
(by 4,7 times), which added to copper in other bond.
It follows from the presented in [4] analysis of conditions and results of impact contact
for some metal bodies (Fe56, W184, U238) that in conventional impacts (without additional
wave pressure of electrophysical fields of additional energy effects) the selection of excess
energy exceeding kinetic energy and evaporation of metals are observed since the order of
values α ≈ 0,1. So if for rather light metal the selection of excess energy is already noticed
from considered [4] (Fe56) at α = 0,08 in observable practice, then for nearest heavier (W184) it
is not in these tests marked at all even at α = 0,09. By analogy in the same range α = 0,6÷0,7
a meteorite (Fe56) with preimpact rate υ ≈ 3000 m/s evaporates completely, and the armourpiercing shell (U238) with preimpact velocity υ ≈ 1700 m/s evaporates only partly (20 %).
Rates of contact mechanical processes at modern conventional cutting-grinding by tools made
of superhard materials in practice of the development of industrial techniques do not usually
exceed 150-200m/s [9, 10], and rare – 300 m/s [11]. Thus machining process with rates over
250 m/s is already related to high-speed one [11]. It is obvious from tab. 1 that modern limits
of grinding rates in conventional processes for all metals are rather far from necessary for at
least fractional immediate sublimation of removable allowance.
Scientific novelty in the elucidation of destruction processes of metals in working area
of diamond-spark grinding and other types of the combined processing using high-speed
processes of the influence on metal and electric currents in the processing area (for example,
processes of electroerosive machining), is not only in the interpretation and development with
regard to them the newest ideas about possibility of metal explosion by force of mechanical or
electric effects especially as such explosion can be unachievable or inexpedient for technical
and economic reasons at the available level of practical adoption of separate technical and
technological innovations. At the state-of-the-art techniques and technologies, the combined
decision of such problems when effects of mechanical and electric influences supplement and
strengthen each other with achievement of qualitatively new integrated result, in particular
with selective predestruction and the metal destruction, allowing to create working processes
of the raised efficiency, stability and controllability is much more important.
The technique of diamond-spark grinding [1, 12-14] noted by the Cabinet of Ministers of
Ukraine within the framework of the nation-wide action devoted to the 20 anniversary of the
country independence "Barvysta Ukraina" as "the Best domestic commodity 2011" is an
effective instance of the combined approach to such solutions.
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REFERENCES
[1] Bezzubenko N. K. Increase of diamond grinding efficiency by introduction in a
cutting zone the additional energy in the form of electric discharges / Tesis for a
Doctor's degree. – Kharkov, 1995 – 457 p. – In Russian.
[2] Palatnik L. S. About character of electrical erosion on monocrystals //
Crystallography. – 1957. – V. 3. – PP. 612-616. – In Russian.
[3] Fuks M. Ya., Bezzubenko N. K., Sverdlova B. M. Surface layer condition of
materials after diamond and borazon processing. – Kiev. – Vyshcha shkola, 1979.
– 160 p. – In Russian.
[4] Marakhtanov M., Marakhtanov А. Metal blows up! // Science and life. – 2002.
– No. 4. – PP. 16-19. – In Russian.
[5] Element properties / Reference book. Ed. by Dritz M. E. – Moscow: Metallurgy,
1985. – 672 p. – In Russian.
[6] Chemistry / Reference guide. Translate from German. – Leningrad: Chemistry,
1975. – 576 p. – In Russian.
[7] Livshitz A. L., Volkov Yu. S. About physical mechanism of metal evacuation out of
hole // Electrophysical and electrochemical methods of processing. – 1974. – Issue 12.
– PP. 1-4. – In Russian.
[8] Gutsalenko Yu. G. Influence of wheel bond on tooling backup costs of diamond
grinding // Bulletin of KhSPU. – 2000. – Issue 99. – PP. 57-59. – In Russian.
[9] Xiu S., Luo J., Sun Z. Study on properties of grinding fluid jet and nozzle
position for super-high speed point grinding // Advanced Materials Research. –
Vol. 135 (2010). – PP. 452-457. – Online since 2010/Oct./19 at www.scientific.net .
[10] Zhang J. Q., Pang Z. R., Guan P., Wang W. S., Pi H. Z. Optimization of
segmented grinding wheel matrix based on super-high speed grinding // Advanced
Materials Research. – Vol. 135 (2010). – PP. 355-360. – Online since 2010/Oct./19 at
www.scientific.net .
[11] Hou Y. L., Li C. H., Liu G. Y. Investigation into high-speed/super-high speed
grinding // Advanced Materials Research. – Vols. 189-193 (2011). – PP. 41084111. – Online since 2011/Feb./21 at www.scientific.net .
[12] Gutsalenko Yu. G. Electroerosion diamond grinding // MicroCAD 2005,
Section M: Production Engineering and Manufacturing Systems / Proceedings of
the International Scientific Conference 10-11 March 2005. – University of
Miskolc (Hungary). – PP. 165-168.
[13] Bezzubenko N. K., Gutsalenko Yu. G. Diamond-spark grinding: brief survey
about development of the Kharkov scientific school to the physics of cutting
operations // Information technologies: science, technics, technology, education,
health / Matters of International Theoretical and Practical Conference 18-19 May
2006 devoted to the M. F. Semko's 100th anniversary. – Kharkov: Cursor
Publishing House, 2006. – PP. 60-66. – In Russian.
[14] Bezzubenko N. K., Gutsalenko Yu. G. Intensive grinding and special design
machines // Eastern-European Journal of Enterprise Technologies. – 2010. –
No. 5/1(47). – PP. 70-71. – In Russian.
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Editura “Academica Brâncuşi” , Târgu Jiu, ISSN 1844 – 640X
MODELING OF RUNNING CUTTERS FOR SHAPING OF
IMPROVED NONINVOLUTE TOOTH GEARS
Tatyana TRETYAK1, Yury GUTSALENKO2, Alexander MIRONENKO3
National Technical University ―Kharkov Polytechnic Institute‖, Ukraine
1,3
Associate Professor, 2Senior Staff Scientist
1,3
[email protected], [email protected]
Abstract: The questions of tooling design for production of advanced gears are considered.
Engineering is based on the special applied development of the mathematical theory of multiparametric
mappings of space. In fulfilled engineering of gear cutting tools for shaping of noninvolute gears it is provided
for exclusion of distorted profiling after tool regrinds. There are proposed calculation algorithms, which may be
used in dataware of respective CAD/CAM systems of maintenance for tooling backup. Among developed tools
there are assembled shaping cutters with prismatic and round cutters. Compensatory possibilities of proposed
assembled shaping cutters are ensured by repositioning of shaped cutting edges after their regrindings: by linear
displacement of prismatic shaped cutters and angular displacement of round ones respectively.
Keywords: advanced gearing, constant normal pitch, gear cutter, multiparametric mappings of space
1. INTRODUCTION
At the advanced production associations the great attention is given to creation of united
information platforms and development of simulation modeling. Simulation modeling is most
successfully applied in tool production as in the high technology field of machining. Proposed in
this paper a model of running tools is a set of geometrical and physical-mechanical components.
Shaping for such tools is carried out by surface generation method at which work and machine-tool
gearings coincide. It allows to increase considerably speed and accuracy of products processing.
At resharpening of monolithic shaped gear cutter for processing of noninvolute gears the
form of a cutting edge changes. Besides, the form error of tooth gear to be machined occurs
due to reduction of center-to-center spacing at displacement of gear cutter. In this connection
the problem of development of tools, after resharpening of which noninvolute profile of tooth
gear to be machined does not change geometrically, becomes topical.
Assembled gear cutters with prismatic and round shaped cutters can be considered as the
types of running gear cutting tools for generation of geometry of tooth gear with noninvolute
profile. Their advantage is that the form of cutting edges is not deformed when resharpening.
Displacement of prismatic cutters by the relevant distance or rotation of round cutters about
relevant angle after each resharpening compensate shaped cutting edges displacement relatively
gear cutter axis caused by such resharpening. Besides, proposed assembled gear cutters allow
quantity of resharpenings several times as much in comparison with the monolithic ones.
2. PROFILING OF ASSEMBLED SHAPING CUTTERS
The sequence of shaping of these tools is defined by the fact that gear cutter as running tool is
a set of shaped cutters (generating ones in relation to a tool surface and contacting ones in relation to
a tooth gear surface to be formed) [1, 2].
The first stage of profiling of assembled gear cutters consists in finding of a tool surface
as an envelope. Tooth flank surfaces of gear to be machined and tool surface of the cutting
tool are profiled cylindrical ones, they are located in reference points x1y1z1 and x2y2z2 (fig. 1,
example for assembled gear cutter with prismatic shaped cutter).
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Figure 1:To calculation of the profile of assembled shaping cutter with
prismatic shaped cutters
The initial information at the first stage is the coordinates of points of a profile of
processed gear x1К, y1К in gear reference point x1y1z1 and the greatest radius of generating
gear R2. Coordinates of points of profile of tool surface x 1И, y1И in gear cutter reference point
x2y2z2 are unknown quantities.
The algorithm of calculation of enveloping surfaces for running tools and processed
tooth gears can be used to find a profile of tool surface conjugated to the predetermined
profile of the processed tooth gear [3].
The second stage of profiling of assembled gear cutters consists in a finding of a shaped
cutting edge as a line of crossing of tool surface and rake face. The initial information is
coordinates of points of profile of cylindrical tool surface in reference point of gear cutter x2y2z2
and rake . Coordinates of shaped cutting edge in the reference point of cutter, marked in fig. as
x3y3z3, are unknown quantities.
The cylindrical tool surface is formed by action of the operator of parallel shift  on its
profile. In reference point of gear cutter x2y2z2 its equation has the following operator and matrix
notations with parameter  :
r2 r2И ,
(1)
m

m

m
,
r
r

(2)
x
x
0






И
2

2



y
;m

y
;m
0
.






where m
(3)
r
2
r
2
И

2
2
И






x
x


2
2
И






2
2И
The rake face (plane) is formed by action of two operators of parallel shift 1 and 2 on
base point of cutting edge with coordinates x2б, y2б, z2б [2]. Having directed the vectors of
carryover as shown in figure, we will write down the operator and matrix equation of face
plane in reference point of gear cutter x2y2z2with parameters  1 and  2 :
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r
r


2
2
б
1
2,
(4)
(5)
m

m

m

m
,
r
r


2
2
б
1
2
x
0


cos







2
б


 
2 

y
;m



;m

.




 0
where m
r
2
б

1

2
б
1
2






z
0


sin

2
б
2






For assembled gear cutter with prismatic shaped cutters
x2б c23R
y 2б  0;
2;
(6)
z 2б  0,
(7)
and for assembled gear cutter with round shaped cutters
x

c

R
cos

; y 2б  0;
2
б
23
z2б 
R
sin

,
(8)
c23– center-to-center spacing of reference points x2y2z2 and x3y3z3,  – clearance angle, R –
the biggest radius of tool.
Having equated the right parts of the equations (2) and (5), we obtain the condition of
crossing of tool surface and rake face in matrix notation:
m

m

m

m

m
.
r

r


2
И
2
б
1
2
(9)
This condition includes three equations with parameters of tool surface and rake face.
Their solution makes possible to define unknown parameters  ,  1 ,  2 , and then by means
of the equation (5) to define coordinates of points of cutting edge X2, Y2 , Z2 in reference point
of gear cutter x2y2z2.
For implementation of next stage of profiling it is necessary to write down coordinates of
points of shaped cutting edge in cutter reference point x3y3z3.
The operator and matrix equations of transition from reference point of gear cutter x2y2z2
to cutter reference point x3y3z3 by means of coordinate operator c23 write down as follows:
r
r

с
,
3
РК
2
РК
23
(10)
m
m
m
r 
r 
c ,
(11)
3
РК
2
РК
23

3sin


0 .
where m
3 
 cos

 3 
(12)
The third stage of profiling of assembled gear cutters consists in the analytical description of
shaped back surface of rotation in reference point of cutter and a finding of profile of this surface in
standard cross-section. The initial information at this stage is coordinates of points of shaped cutting
edge, tool clearance , and also the maximum radius R for round shaped cutter.
The cylindrical flank surface of prismatic shaped cutter can be formed by action of the
operator of parallel shift  on shaped cutting edge [2]. Its equations in operator and matrix notation
are as follows:
r3 r3РК3,
(13)
m
m

m
,
r
r

3
3
РК
3
(14)

3sin


0 .
where m
3 
 cos

 3 
(15)
Flank surface of round shaped cutter can be formed by action of the rotation operator
on shaped cutting edge [2]. Its equations in operator and matrix notation are as follows:
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r3 r3РК,
(16)
m
m
r3 
m
r3РК,
(17)
cos
0 
sin





0 .
 0 1

where m
sin


  0 cos

(18)
Let's draw an axial plane of standard cross-section N-N. Its operator and matrix
equations with parameters x3Н and y3Н in cutter reference point x3y3z3 write down as follows:
r3  r3Н ,
(19)
mr3 mr3H ,
where mr
3H
(20)
 x3H 


  y3H  .
 0 


(21)
Having equated the right parts of the equations (14) and (20) we will obtain the
condition of crossing of flank surface of prismatic shaped cutter and standard cross-section
plane in matrix notation:
m

m

m
.
r

r
3
РК
3
3
H
(22)
This condition includes three equations with parameters of flank surface and standard
cross-section plane. Their solution allows to define unknown parameters  3 , x3Н and y3Н and
connected with x3Н parameter z3Н, and hereby to find coordinates of points of required profile
of flank surface of prismatic shaped cutter in standard cross-section.
Having equated the right parts of the equations (17) and (20) we will obtain the
condition of crossing of flank surface of round shaped cutter and standard cross-section plane
in matrix notation:
m  mr
3PK
= mr .
3H
(23)
It includes three equations with parameters of flank surface and standard cross-section
plane. Their solution allows to define unknown parameters , x3Н, and y3Н, and thus to find
coordinates of points of required profile of flank surface of round shaped cutter in standard
cross-section.
3. PHYSICAL-MECHANICAL SIMULATION OF GEAR CUTTER LOADING
On the basis of the obtained set of equations, the geometrical model of tool which was a
basis for the FEM strength and a heat analysis at processing is developed (fig. 2).
The adequacy of FEM model for shaping element with reproduction accuracy of boundary
conditions, loading, geometry and properties of material was defined at the first stage of the
investigation. Investigations on determining of total displacements (fig. 3), equidistant
deformation by Mises criterion and equidistant pressure by Mises criterion (fig. 4) under
condition of pressure application to surface normal, resultant of which is 4000 N (~400 kg)
for the materials of high-speed steels group were carried out.
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Figure 2: Geometrical model of gear cutter
(full)
Figure 3: Resultant displacements [m]
Figure 4: Equivalent stress [Pa]
Maximal equivalent stress according to Mises criterion, calculated with averaging on
nodal point, is =5550 MPa.
Given calculated model is not accurate since it leads to setting stiffness too high in
comparison with reality which means that it leads to occurring of error too. Distributed load
application on the surface allows to decrease the error caused due to application of equivalent
force. And with it the direction of distributed load should coincide with axis of cylindrical
surface.
Taking into account carried out calculations and secondary analysis, the sector model which
includes 5 teeth (fig. 5), fixing scheme and distributed load (fig. 6).
Figure 5: Geometrical model of gear
cutter sector and boundary conditions
168
Figure 6: FEM model of gear cutter
under loading
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Editura “Academica Brâncuşi” , Târgu Jiu, ISSN 1844 – 640X
A set of experiments are worked out and exacted data array (fragment is presented in
table 1), which permit to make conclusion on strength analysis of running gear cutting tool
and change of parameters at increase of contact sites, that correspond to tool blunting, is
obtained.
Table 1: Load (F), temperature (T) and strength () FEM calculation simulation
N
tooth
1
2
3
F1
[MPa]
4000
4000
4000
F2
[MPa]
3000
F3
[MPa]
2000
2000
F4
[MPa]
-
T1
[C]
618
611
615
T2
[C]
408
T3
[C]
314
308

[MPa]
3720
3760
3800
4. CONCLUSION
The optimized geometrical model, simulation FEM model of gear cutter, considering its
physical-mechanical properties on the basis of which it is possible to recommend material and
geometrical parameters of cutting elements for the assembled tool of equidistant tooth
generation on noncylindrical surfaces of two-parameter gearing [4] are the findings of the
carried out investigations.
REFERENCES
[1] Rodin P.R. Fundamentals of shaping of surfaces by cutting. K., Vyshcha shkola, 1977.
192 p. (in Russian)
[2] Perepelitsa B.A. Development of the theory of shaping of surfaces by cutting and cutting
tools by means of mappings of affine space. D. Sc. Thesis. – Tula, 1981. – 359 p. (in
Russian)
[3] Kondusova E.B. Tretyak T.E., Krivosheya A.V. Algorithm of calculation of profile of
enveloping surfaces for running tools and components. Proceedings of the fifth
International Conference ―New Leading-Edge Technologies in Machining Building‖,
Rubachie, Ukraine, September 18-21, 1996, рр. 140-141. (in Russian)
[4] Gutsalenko Yu., Mironenko A., Tretyak T. Equidistant tooth generation on
noncylindrical surfaces for two-parameter gearing. Fiability & Durability, Targu- Jiu,
CBU, 2011, No. 2(8), pp. 67-72.
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FROM ZERO-DIMENSIONAL TO 2-DIMENSIONAL CARBON
NANOMATERIALS - part I: TYPES OF CNs
prof.PhD.eng., Cătălin IANCU,
Engineering Faculty,‖C-tin Brâncuşi‖ Univ. of Tg-Jiu, [email protected]
Abstract: In recent years, many theoretical and experimental studies have been carried out to develop
one of the most interesting aspects of the science and nanotechnology which is called carbon-related
nanomaterials. In this review paper are presented some of the most important developments in the
synthesis, properties, and applications of low-dimensional carbon nanomaterials. The synthesis
techniques are used to produce specific kinds of low-dimensional carbon nanomaterials such as zerodimensional CNs (including fullerene, carbon-encapsulated metal nanoparticles, nanodiamond, and
onion-like carbons), one-dimensional carbon nanomaterials (including carbon nanofibers and carbon
nanotubes), and two-dimensional carbon nanomaterials (including graphene and carbon nanowalls).
Keywords: graphene, carbon nanomaterials (CNs), synthesis techniques.
1. INTRODUCTION
Low-dimensional carbon nanomaterials can be divided into categories of different
dimensionality ranging from zero-dimensional (0-D) to one-dimensional (1-D) and twodimensional (2-D) depending on their nanoscale range (<100 nm) in different spatial
directions. The representatives in family of low-dimensional carbon nanomaterials focus on
fullerene, onion-like carbon, carbon-encapsulated metal nanoparticles, nanodiamond (0-D),
carbon nanofibers, carbon nanotubes (1-D), graphene, and carbon nanowall (2-D) (fig.1[1]).
Figure 1. Different forms of carbon nanomaterials [1]
In the past decade, by using nanotechnology and carbon-based nanomaterials, the
world might be able to see an industrial revolution surpassing any one before. This new
technology could end the world‘s hunger, make affordable goods, have massive implications
for medical breakthroughs, and unfortunately also be used in military applications. The latest
research results and developments, hopefully may lead more researchers to address the area
and look forward to more research results.
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2. TYPES OF CNs
The types and structure description of carbon nanomaterials is as follows:
2.1. Zero-Dimensional Carbon Nanomaterials (0-DCNs)
2.1.1. Fullerene
Fullerenes are spherical, caged molecules with carbon atoms located at the corner of a
polyhedral structure consisting of pentagons and hexagons. A spherical fullerene looks like a
soccer ball and is often called ―buckyball.‖ Fullerenes were named after Richard Buckminster
Fuller, an architect known for the design of geodesic domes which resemble spherical
fullerenes in appearance. In fact, fullerenes were discovered as an unexpected surprise during
laser spectroscopy experiments in 1985, by researchers at Rice University. As mentioned in
the Nobel Prize records, the 1996 Nobel Prize in chemistry was awarded jointly to Robert F.
Curl, Jr., Richard E. Smalley, and Sir Harold W. Kroto ―for their discovery of fullerenes‖.
The first method of production of fullerenes, by Kroto et al. in 1985 [2] used laser
vaporization of carbon in an inert atmosphere in which microscopic amounts of fullerenes
were produced.
2.1.2. Carbon-Encapsulated Metal Nanoparticles (CEMNPs)
Carbon-encapsulated metal (magnetic) nanoparticles (CEMNPs) represent a new class
of Zero-dimensional carbon-metal composite nanomaterials. It is the shape of core-shell
structure on the nanoscale. The polyhedral metallic core is entirely encapsulated by the
multilayer-graphitized carbon shell. So, the carbon layers isolate the particles magnetically
from external environment and protect them against corrosion and magnetic coupling between
individual particles.
Since the first report on LaC2 encapsulated within nanoscale polyhedral carbon
particles in a carbon arc synthesized by Ruoff et al. [3] in 1993, carbon-encapsulated metal
nanoparticles have received considerable attention because of their novel structures and
obvious technological promise. Scientist have succeeded in encapsulating various materials
into a hollow graphitic cage by arc discharge method. Saito [4] reported that 13 rare earth
metals and iron-group metals were wrapped in graphitic carbon in 1995. In summary,
CEMNPs can be synthesized by a variety of techniques such as arc discharge method,
tungsten arc techniques, high-temperature heat treatments, the mechanical milling,
cocarbonization, pulsed laser irradiation, and high-current pulsed arcs system.
2.1.3. Nanodiamond (ND)
As is well known, diamond is one of the carbon allotropes as graphite. Graphite is the
most stable form of carbon at ambient pressure. Spherical and truncated octahedron diamond
with predominant sp3-bonded carbon is one of the hardest materials known to date and is
often regarded as the king of all gemstone and top-drawer materials because of its excellent
scientific qualities in hardness, chemical corrosiveness, thermal expansion and conductivity,
electrical insulation, and biocompatibility. On the other hand, nanodiamond (ND) is a cubic
structural diamond. It possesses diamond structure and diamond properties. The average size
is mere 5 nm in diameter. In the wide sense of the word, ―nanodiamond‖ contains a variety of
diamond-based materials at the nanoscale (the length scale of approximately 1–100 nm)
including pure-phase diamond films, diamond particles, and their structural assemblies.
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Several synthesis methods have been developed to synthesize laboratory-produced
nanodiamonds. There are two main methods for fabrication of nanodiamond: transformation
of graphite under high temperature and high pressure and detonation of the carbon explosive
materials.
In 1955, Bundy et al. [5] realized the 30-year dream of many scientists in which
diamond can be transformed from graphite, as they successfully reported the synthesis of
diamond using a high-temperature and high-pressure process. However, the synthesis of
diamond by the detonation of explosives with a negative oxygen balance in a steel container
under vacuum condition was reported in the 1980s [6]. There are also some related literatures
in recent reports shown two mentioned methods [7]. Explosive detonation is still widely used;
however, the process of the detonator explosion is extremely fast and very complex.
Moreover, there are some disadvantages observed in detonation method. In fact, the fraction
of surface to bulk atom and oxygen, hydrogen, and nitrogen content in the nanodiamond
resulting from after- purification process are difficult to remove.
As an interesting matter, most previous researches on detonation synthesis have been
done at military or commercial plants; thus several reports are available for the scientific
community. Therefore, the best method is to develop new techniques to the synthesis of welldispersed and pure nanodiamonds. Recently, more researches also about the aspects of low
energy, low cost, easily controlled, few byproducts, controlled-sized, and large scale have
been reported in related literatures, such as microwave plasma chemical vapor deposition [8],
hot filament chemical vapor deposition, pulse laser ablation [9], electron irradiation [10], and
high-energy X-ray diffraction [11].
2.1.4. Onion-Like Carbons (OLCs)
Ugarte [12] in 1992 reported that carbon soot particles and tubular graphitic structures
were radiated by intense electron-beam and reorganized into quasispherical particles.
Subsequently, Harris and Tsang [13] in 1997 studied the structure of two typical
nongraphitizing carbons by heat treatment. They observed the fullerene-like structure close to
carbon nanoparticles. Then, a new model for nongraphitizing carbons was proposed which
was different with the other representatives of the carbon family graphite, fullerenes, and
nanotubes. The onion-like carbons (OLCs) have the three to eight closed graphitic shell
structures with the hollow core. The outer diameters are in the range of 20–100 nm. The
polyhedral nanoparticles exhibited a well aligned concentric and high degree of symmetry
structure. Quasispherical shape, nanometer size, and surface specificity of OLCs have
attracted enormous attention. Several routes were developed from synthesis of carbon onions
including arc discharge, high-electron irradiation, chemical vapor deposition, radio frequency
plasma and high-dose carbon ion implantation into metals, and thermal annealing of diamond
nanoparticles [14]. The current researches on OLCs are limited because of unmanageable
reaction, many byproducts, complex equipments, and high cost. At present, the most OLCs
were synthesized using vacuum annealing of nanodiamond at fixed temperatures [15].
2.2. One-Dimensional Carbon Nanomaterials (1-DCNs)
2.2.1. Carbon Nanofibers
Carbon nanofibers (CNFs) are composed of stacked and curved graphene layers from
a quasi-one-dimensional (1D) filament. CNFs have cylindrical or conical nanostructures.
Their diameters vary from a few to hundred nanometers, while lengths range from less than a
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micrometer to millimeters. According to the angle between graphene layers and fiber axis, the
morphological structure is often divided into plate CNFs, ribbon-like CNFs, herringbone
CNFs [16].CNFs known as filamentous carbon have been known for a long time [17].
However, the synthesis of filamentous carbons did not evoke great interest of scientists in
those early years until the discovery of carbon nanotubes by Iijima in 1991. Generally, CNFs
can be synthesized through the traditional vapor growth method, cocatalyst deoxidization
process, catalytic combustion technique, plasma-enhanced chemical vapor deposition, hot
filament-assisted sputtering, ultrasonic spray pyrolysis, and ion beam irradiation.
2.2.2. Carbon Nanotubes (CNT)
Carbon nanotubes are rolledup into tubular structures by sp2-bonded graphite sheets
with nanometer diameter and large length ratio. The nanotubes may consist of two different
types of carbon nanotubes. Namely, singlewall nanotubes (SWNTs) made of single layers of
graphene cylinders with typical diameter of the order of 1.4 nm and the multiwall nanotubes
(MWNTs) made of 4–24 concentric cylinders of graphene layers with adjacent shells
separation of 0.34 nm and a diameter typically of the order 10–20 nm. Nowadays, carbon
nanotubes are still mainly synthesized by the arc-discharge, laser-ablation (vaporization), and
chemical vapor decomposition (CVD) method.
The MWNTs were first observed which deposited on the negative electrode during the
direct current arc-discharge of two graphite electrodes for preparation of fullerenes in an
argon-filled vessel by Iijima in 1991 [18]. Vast amount of reviews on carbon nanotubes have
been discussed in the recent literature in detail, including the synthesis and growth
mechanisms of CNT [19].
2.3. Two-Dimensional Carbon Nanomaterials (2-DCNs)
2.3.1. Graphene
Graphene, one-atom-thick planar sheet of sp2-bonded carbon atoms, is arranged
densely in a two-dimensional hexagonal honeycomb crystal lattice. There are three extremely
strong σ bonds in-plane result in the mechanical stability of the carbon sheet, π orbitals
perpendicular to the plane interactions between graphene and a substrate or between graphene
layers are responsible for the electron conduction. It is the basic building block of (0-D)
fullerenes, (1-D) carbon nanotubes, and (3-D) graphite.
Diamond and graphit have been known for centuries, and the recently discovered
fullerenes and nanotubes also have been studied in the last two decades. For a long time,
graphene was only considered as theoretical concept. Until 2004, [20] a physicists group led
by Andre Geim and Kostya Novoselov from Manchester University, UK used mechanical
exfoliation approach to obtain graphene. The discovery of isolated graphene monolayer has
attracted wide attention to investigate the properties of this new yet ancient two-dimensional
carbon nanomaterial due to its exceptional electronic and mechanical properties [21]. More
and more simple methods were searched for the growth of graphene. Several typical methods
have been developed and will be presented in part II of the paper.
2.3.2. Carbon Nanowalls
Carbon nanowalls (CNWs) consist of vertical aligned graphene sheets standing on the
substrates, form two-dimensional wall structure with large surface areas and sharp edges. The
thickness of CNWs ranges from a few nm to a few tens nm. So far, research groups have
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explored different synthesis methods of CNWs based on plasma-enhanced chemical vapor
deposition techniques. The main approaches are as follows: 1-Microwave plasma-enhanced
chemical vapor deposition (MWPECVD); 2-Radio-frequency plasma-enhanced chemical
vapor deposition (RFPECVD) (RF inductively coupled plasma (ICP) and RF capacitively
coupled plasma (CCP); 3-Hot-wire chemical vapor deposition (HWCVD); 4-Electron beam
excited plasma-enhanced chemical vapor deposition (EBEPECVD).
For the first time, carbon nanowalls were accidentally discovered during the growth of
carbon nanotubes by Wu et al. [22] using MWPECVD. In the experiment, the NiFe-catalyzed
substrate (Si, SiO2/Si, sapphire) was preheated to about 650–700°C in hydrogen plasma; the
mixtures of CH4 and H2 were utilized as flow gases. The well-controlled MWPECVD
synthesis process induced further studies to search more flexible control of the growth of
CNWs, which aided to understand the mechanisms of CNWs growth and solving unwanted
byproduct owing to the use of metal catalyst particles.
Recently, some groups have prepared CNWs without catalysts, using RFPECVD,
assisted by a hydrogen atom injection. Shiji et al. [23] synthesized carbon nanowalls on a Si
substrate without catalysts using capacitively coupled RFPECVD by H atom injection. The
grown samples employed fluorocarbon/hydrogen mixtures, used C2F6, CF4, CH4, and
CHF3 as the carbon source gas, and heated a substrate temperature of 500°C.
3. CONCLUSIONS
As described in this paper, the unique structure and properties of low-dimensional
carbon nanomaterials as the advanced materials have led them to have a strong and important
potential role in various scientific fields and engineering such as nanoscale electronic devices,
field emission displays, diodes, transistors, sensors, composite polymers, artificial muscles,
mechanical reinforcements, capacitors, and hydrogen storage. For example, carbon nanobuds
are the recently produced materials from two previously known allotropes of carbon
nanotubes and fullerenes. These fullerene-like ―buds‖ have found the unique properties of
both fullerenes and CNTs which have many applications as good field emitters as well as their
role to improve the mechanical properties of composites. As another example, the application
of CNTs to develop the biofuel products is being noticeably growing.
As the definition of the low-dimensional carbon nanomaterial, these materials also
cover a wide range of carbon-related nanostructures such as nanodiamonds, fibers, cones,
scrolls, whiskers, and graphite polyhedral crystals. In fact, there are expectable outlooks for
the use of these materials in the fields of molecular electronics, sensoring,
nanoelectromechanic devices, field-emission displays, energy storage, and composite
materials, as well as their growing applications in medical science, health, and daily life.
BIBLIOGRAPHY
[1]. Iancu C., Stăncioiu A., Graphene: a new material, 4th Symposium with international
participation ―Durability and reliability of mechanical systems‖, Tg-Jiu, ISBN 978-973-144454-3, 2011
[2]. H. W. Kroto, J. R. Heath, S. C. O'Brien, R. F. Curl, and R. E. Smalley, ―C60:
buckminsterfullerene,‖Nature, vol. 318, no. 6042, pp. 162–163, 1985.
[3]. R. S. Ruoff, D. C. Lorents, B. Chan, R. Malhotra, and S. Subramoney, ―Single crystal
metals encapsulated in carbon nanoparticles,‖ Science, vol. 259, no. 5093, pp. 346–348, 1993.
174
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[4]. Y. Saito, ―Nanoparticles and filled nanocapsules,‖ Carbon, vol. 33, no. 7, pp. 979–988,
1995.
[5]. F. P. Bundy, H. T. Hall, H. M. Strong, and R. H. Wentorf, ―Man-Made diamonds,‖
Nature, vol. 176, no. 4471, pp. 51–55, 1955.
[6]. N. R. Greiner, D. S. Phillips, J. D. Johnson, and F. Volk, ―Diamonds in detonation
soot,‖ Nature, vol. 333, no. 6172, pp. 440–442, 1988.
[7]. K. Iakoubovskii, M. V. Baidakova, B. H. Wouters, A. Stesmans, G. J. Adriaenssens, A.
YA. Vul', and P. J. Grobet, ―Structure and defects of detonation synthesis
nanodiamond,‖ Diamond and Related Materials, vol. 9, no. 3–6, pp. 861–865, 2000.
[8] V. S. Purohit, D. Jain, V. G. Sathe, V. Ganesan, and S. V. Bhoraskar, ―Synthesis of nano
crystalline diamonds by microwave plasma,‖ Journal of Physics D, no. 6, pp. 1794–1800,
2007.
[9]. L. Vandenbulcke, T. Gries, and J. N. Rouzaud, ―Nanodiamonds in dusty low-pressure
plasmas,‖Applied Physics Letters, vol. 94, no. 4, Article ID 044106, 2009.
[10]. L. Hawelek, A. Brodka, J. C. Dore, V. Honkimaki, S. Tomita, and A. Burian, ―Structural
studies of nanodiamond by high-energy X-ray diffraction,‖ Diamond and Related Materials,
vol. 17, no. 7–10, pp. 1186–1193, 2008.
[11]. D. Amans, A. C. Chenus, and A. C. Chenus, ―Nanodiamond synthesis by pulsed laser
ablation in liquids,‖ Diamond and Related Materials, vol. 18, no. 2-3, pp. 177–180, 2009.
[12]. D. Ugarte, ―Morphology and structure of graphitic soot particles generated in arcdischarge C production,‖ Chemical Physics Letters, vol. 198, no. 6, pp. 596–602, 1992.
[13]. W. Kratschmer, L. D. Lamb, K. Fostiropoulos, and D. R. Huffman, ―Solid C60: a new
form of carbon,‖ Nature, vol. 347, no. 6291, pp. 354–358, 1990.
[14]. B. S. Xu and S. I. Tanaka, ―Formation of giant onion-like fullerenes under Al
nanoparticles by electron irradiation,‖ Acta Materialia, vol. 46, no. 15, pp. 5249–5257, 1998.
[15]. M. Bystrzejewski, M. H. Rummeli, T. Gemming, H. Lange, and A. Huczko, ―Catalystfree synthesis of onion-like carbon nanoparticles,‖ New Carbon Materials, vol. 25, no. 1, pp.
1–8, 2010.
[16]. S. Iijima, ―Helical microtubules of graphitic carbon,‖ Nature, vol. 354, no. 6348, pp. 56–
58, 1991.
[17]. E. P. S. Tan, C. N. Goh, C. H. Sow, and C. T. Lim, ―Tensile test of a single nanofiber
using an atomic force microscope tip,‖Applied Physics Letters, vol. 86, no. 7, Article ID
073115, 2005.
[18]. S. Iijima and T. Ichihashi, ―Single-shell carbon nanotubes of 1-nm diameter,‖ Nature,
vol. 363, no. 6430, pp. 603–605, 1993.
[19]. P. M. Ajayan and T. W. Ebbesen, ―Nanometre-size tubes of carbon,‖ Reports on
Progress in Physics, vol. 60, no. 10, pp. 1025–1062, 1997.
[20]. K. S. Novoselov, A. K. Geim, S. V. Morozov, et al., ―Chiral tunnelling and the Klein
paradox in graphene,‖ Nature, vol. 438, pp. 197–200, 2005.
[21]. A. K. Geim and K. S. Novoselov, ―The rise of graphene,‖ Nature Materials, vol. 6, no.
3, pp. 183–191, 2007.
[22]. Y. Wu, P. Qiao, T. Chong, and Z. Shen, ―Carbon nanowalls grown by microwave
plasma enhanced chemical vapor deposition,‖ Ad. Materials, vol. 14, no. 1, pp. 64–67, 2002.
[23]. K. Shiji, M. Hiramatsu, A. Enomoto, M. Nakamura, H. Amano, and M. Hori, ―Vertical
growth of carbon nanowalls using rf plasma-enhanced chemical vapor deposition,‖ Diamond
and Related Materials, vol. 14, no. 3–7, pp. 831–834, 2005.
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FROM ZERO-DIMENSIONAL TO 2-DIMENSIONAL CARBON
NANOMATERIALS - part II: GRAPHENE
prof.PhD.eng., Cătălin IANCU,
Engineering Faculty,‖C-tin Brâncuşi‖ Univ. of Tg-Jiu, [email protected]
Abstract: As was presented in the first part of this review paper, lately, many theoretical and
experimental studies have been carried out to develop one of the most interesting aspects of the science
and nanotechnology which is called carbon-related nanomaterials. In this review paper are presented
some of the most exciting and important developments in the synthesis, properties, and applications of
low-dimensional carbon nanomaterials. In this part of the paper are presented the synthesis techniques
used to produce the two-dimensional carbon nanomaterials (including graphene), and also the most
important properties and potential applications of graphene.
Keywords: graphene, carbon nanomaterials (CNs), synthesis techniques.
1. INTRODUCTION- 2D-GRAPHENE
Graphene is a 2-dimensional network of carbon atoms. These carbon atoms are bound
within the plane by strong bonds into a honeycomb array comprised of six-membered rings.
By stacking of these layers on top of each other, the well known 3-dimensional graphite
crystal is formed. Thus, graphene is nothing else than a single graphite layer (figure 1).
Figure 1. Graphene – 1 layer graphite
Until now graphene of sufficient quality has only been produced in the form of small
flakes of tiny fractions of a millimeter, using painstaking methods such as peeling layers off
graphite crystals with sticky tape. Producing useable electronics requires much larger areas of
material to be grown. This project saw researchers, for the first time, produce and successfully
operate a large number of electronic devices from a sizable area of graphene layers
(approximately 50 mm2). The graphene sample, was produced epitaxially - a process of
growing one crystal layer on another - on silicon carbide. Having such a significant sample
not only proves that it can be done in a practical, scalable way, but also allowed the scientists
to better understand important properties [1] [2].
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2. GRAPHENE – OBTAINING METHODS
Until 2004 [3], as described in previous part of this paper, a physicists group led by
Andre Geim and Kostya Novoselov from Manchester University, UK used mechanical
exfoliation approach to obtain graphene. The discovery of isolated graphene monolayer has
attracted wide attention to investigate the properties of this new yet ancient two-dimensional
carbon nanomaterial due to its exceptional electronic and mechanical properties. More and
more simple methods were searched for the growth of graphene. Several typical methods have
been developed and reviewed as follows.
2.1. Mechanical Exfoliation
As mentioned above, [3] graphene flakes (figure 2) were first produced by
continuously cleaving a bulk graphite crystal with a common adhesive tape and then
transferred the thinned down graphite onto a cleaned oxidized silicon wafer substrate with
visible color. The technique started with three-dimensional graphite and extracted a single
sheet (a monolayer of atoms) called mechanical exfoliation or micromechanical cleavage.
Until now, mechanical exfoliation of graphite is still the best method to provide a
small amount of high-quality samples for the study of a variety of graphene properties.
Furthermore, the venerable technique has been used easily to obtain large size (up to
100 μm), high-quality, two-dimensional graphene crystallites, which immediately brought
enormous experimental researches [4]. Meanwhile, modified techniques are needed to provide
a high yield of graphene for industrial production.
Figure 2. Graphene flakes
2.2. Epitaxial Growth
Recently, graphene was obtained by the epitaxial growth of graphene layers on metal
carbides using thermal desorption of metal atoms from the carbides surface, or directly on
metal surfaces by chemical vapor deposition (CVD). The typical carbide is SiC [5]; silicon
carbide heated to very high temperatures leads to evaporation of Si and the reformation of
graphite; the control of sublimation results in a very thin graphene coatings over the entire
surface of SiC wafers, which initially showed more performances than devices made from
exfoliated graphene.
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So far, all of known synthesis approaches, however, are required in specialized
laboratories for graphene sheets whose electronic properties are often altered by interactions
with substrate materials. The development of graphene required an economical fabrication
method compatible with mass production. The latest modified method was demonstrated by
Aristov et al. [6] (figure 3). Based on their work, for the first time, graphene was synthesized
commercially on available cubicβ-SiC/Si substrates, which was a simple and cheap procedure
to obtain industrial mass production graphene, which meets the need of technological
application. Moreover, many other types of carbide have been exploited to produce supported
graphene, such as TiC and TaC. It is well proved that metal surfaces can efficiently catalyze
decomposition of hydrocarbons into graphitic materials to support growth of graphene on
metallic surfaces by CVD. The advantage of epitaxial growth is large-scale area, but it is
difficult to control morphology, adsorption energy, and high-temperature process.
Figure 3: Edge-functionalized graphite
deposited on a silica substrate
2.3. Chemical Exfoliation
The theory of chemical exfoliation is to insert reactants in the interlayer space for
weakening the van der Waals cohesion. At first, the graphite flakes are forced upon oxidative
intercalation of potassium chlorate in concentrated sulphuric and nitric acid, received carbon
sheets with hydroxyl and carboxyl moieties. The suspension is known as graphite oxide (GO).
The GO is highly dispersible in water, and it can be easily deposited onto SiO 2 substrates
(figure 4).
The precipitate of GO is sonicated to form separated graphene oxide sheet, then
another reduction, and finally graphene sheet is formed. When KClO3 is used, it generates a
lot of chlorine dioxide gas and emits a great deal of heat, so the mixture is highly hazardous
[7]. Later was reported a modified method which was much faster and safer. Based on the
technique introduced by them, graphite is dispersed into a mixture of concentrated sulfuric
acid, sodium nitrate, and potassium permanganate in contrast to KClO3. Meanwhile, Chen et
al. [8] successfully achieved thermal reduction of graphene oxide (GO) to graphene with the
assistance of microwaves in a mixed solution of N, N-dimethylacetamide, and water
(DMAc/H2O). The reduction of GO can be accomplished rapidly and mildly.
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This method is rapid, not requiring any solvents or stabilizers, inexpensive, and easy to
scale up.
Figure 4. Chemically exfoliated graphene
3. PROPERTIES AND APPLICATIONS OF CNs
There are several various allotropes of carbon such as graphite, diamond, and
amorphous carbon. Therefore, the physical and mechanical properties of carbon strongly
depended on the allotropic forms of carbon. As an example for the mechanical property of
hardness, diamond is known as one of the hardest materials, while graphite is soft enough to
be used for making pencils. About the property of color, diamond is considered transparent
while graphite is an opaque material and black. As another example, while graphite is a good
conductor, diamond just demonstrates a low electrical conductivity. On the other hand,
diamond is normally known as a highly thermal conductive, while graphite is considered as
the most thermodynamically stable material.
3.1. Graphene
In 2007, Meyer et al. [9] used transmission electron microscopy (TEM) to study the
atomic structure of a single-layer graphene. As they reported, they have studied individual
graphene sheets freely suspended on a microfabricated scaffold in vacuum or the air. The
membranes were only one-atom thick, yet they still displayed long-range crystalline order.
According to their studies using TEM, the suspended graphene sheets are not perfectly flat. In
other words, the suspended graphenes were observed as rippling of the flat sheet, with
amplitude of about 1 nm. As the authors explained, the atomically thin single-crystal
membranes offered ample scope for fundamental research and new technologies, whereas the
observed corrugations in the third dimension may provide subtle reasons for the stability of
two-dimensional crystals.
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3.2. Mobility of Graphene and the applications
Graphene is known as a high electron mobility material at room temperature, so that
the reported value is 15,000 cm2V−1s−1. In 2005, Novoselov et al. [10] considered graphene
as a condensed-matter system in which electron transport is essentially governed by Dirac's
(relativistic) equation. In 2008, Morozov et al. [11] studied temperature dependences of
electron transport in graphene and showed that the electron mobility higher
than 2 × 105 cm2V−1s−1 is achievable if extrinsic disorder is eliminated. In the same year,
Chen et al. [12] studied the intrinsic and extrinsic performance limits of graphene devices on
SiO2. According to the studies mentioned above, it seems that the electron mobility in
graphene should be almost independent of the temperature between 10 K and 100 K.
Due to the high mobility of graphene, this material is known as a promising
nanomaterial particularly for those applications in which transistors need to switch extremely
fast. Furthermore, the high mobility of graphene involves this material in the applications
related to chemical and biochemical sensing.
On the other hand, the resistivity of the graphene sheets is 10−6 Ω cm which is less than
the resistivity of silver as known as the lowest resistivity at room temperature. Such a unique
low resistivity and also the very low thickness of graphene have made this material to have a
great role in many applications such as mechanical fields, electrical conducting, and
transparent films which are necessarily applicable in the field of electronics such as producing
touch screens and photovoltaic cells.
4. CONCLUSIONS
As described in this paper, the unique structure and properties of low-dimensional
carbon nanomaterials as the advanced materials have led them to have a strong and important
potential role in various scientific fields and engineering such as nanoscale electronic devices,
field emission displays, diodes, transistors, sensors, composite polymers, artificial muscles,
mechanical reinforcements, capacitors, and hydrogen storage. For example, carbon nanobuds
are the recently produced materials from two previously known allotropes of carbon
nanotubes and fullerenes. These fullerene-like ―buds‖ have found the unique properties of
both fullerenes and CNTs which have many applications as good field emitters as well as their
role to improve the mechanical properties of composites. As another example, the application
of CNTs to develop the biofuel products is being noticeably growing due to their strongly
deferent properties comparing to the previous products.
As a matter of fact, due to the unique mechanical, optical, and electronic properties of
carbon nanotubes, the publication statistics show that CNTs have successed to attract the main
body of the authors‘ interest since 1991 up to now. However, as described in this paper,
carbon nanomaterials are not limited to CNTs. Therefore, the future outlook of applications of
these materials depends on the capability of the use of each one. As an interesting
bioapplication example, nanodiamonds may be capable to be used for biolistic delivery in
gene therapy, drug delivery, and vaccines as a solid support matrix. Furthermore, there is a
strong possibility in near future to use nanodiamonds in the medical immunoassays as either
the detection tag or the solid support matrix [13].
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As the definition of the low-dimensional carbon nanomaterial, these materials also
cover a wide range of carbon-related nanostructures such as nanodiamonds, fibers, cones,
scrolls, whiskers, and graphite polyhedral crystals. In fact, there are expectable outlooks for
the use of these materials in the fields of molecular electronics, sensoring,
nanoelectromechanic devices, field-emission displays, energy storage, and composite
materials, as well as their growing applications in medical science, health, and daily life [14].
AKNOLEDGEMENTS
I would like to express my consideration and many thanks to Ali Mostofizadeh,
Yanwei Li, Bo Song, Yudong Huang, for permission of free web access and citations from
their article Synthesis, Properties, and Applications of Low-Dimensional Carbon-Related
Nanomaterials, published in Journal of Nanomaterials, Volume 2011 (2011), article
ID 685081, ―in the hope that more researchers can address the area and look forward to more
research results‖ [1].
BIBLIOGRAPHY
[1]. Ali Mostofizadeh, Yanwei Li, Bo Song, Yudong Huang, Synthesis, Properties, and
Applications of Low-Dimensional Carbon-Related Nanomaterials, Journal of Nanomaterials
Volume 2011 (2011), Article ID 685081
[2]. Iancu C., Stăncioiu A., Graphene: a new material, 4th Symposium with international
participation ―Durability and reliability of mechanical systems‖, Tg-Jiu, ISBN 978-973-144454-3, 2011
[3]. K. S. Novoselov, A. K. Geim, S. V. Morozov, et al., ―Chiral tunnelling and the Klein
paradox in graphene,‖ Nature, vol. 438, pp. 197–200, 2005.
[4]. A. K. Geim and K. S. Novoselov, ―The rise of graphene,‖ Nature Materials, vol. 6, no. 3,
pp. 183–191, 2007.
[5] K.V. Emtsev, A. Bostwick, K. Horn, J. Jobst, G.L. Kellogg, L. Ley, J.L. McChesney, T. Ohta,
S.A. Reshanov, J. Röhrl, E. Rotenberg, A.K. Schmid, D. Waldmann, H.B. Weber, Th. Seyller,
Towards wafer-size graphene layers by atmospheric pressure graphitization of SiC,
Nature Materials 8, 2009
[6]. Victor Yu. Aristov, Grzegorz Urbanik, a.o., Graphene Synthesis on Cubic SiC/Si Wafers.
Perspectives for Mass Production of Graphene-Based Electronic Devices, Nano
Lett., 2010, no.10 (3), pp 992–995
[7]. J. Chattopadhyay, A. Mukherjee, and A. Mukherjee, ―Graphite epoxide,‖ Journal of the
American Chemical Society, vol. 130, no. 16, pp. 5414–5415, 2008.
[8]. W. Chen, L. Yan, and P. R. Bangal, ―Preparation of graphene by the rapid and mild
thermal reduction of graphene oxide induced by microwaves,‖ Carbon, vol. 48, no. 4, pp.
1146–1152, 2010.
[9]. J. C. Meyer, A. K. Geim, M. I. Katsnelson, K. S. Novoselov, T. J. Booth, and S. Roth,
―The structure of suspended graphene sheets,‖ Nature, vol. 446, no. 7131, pp. 60–63, 2007.
[10]. A. K. Geim and K. S. Novoselov, ―The rise of graphene,‖ Nature Materials, vol. 6, no.
3, pp. 183–191, 2007.
[11]. S. V. Morozov, K. S. Novoselov, M. I. Katsnelson, F. Schedin, D. C. Elias, J. A.
Jaszczak, and A. K. Geim, ―Giant intrinsic carrier mobilities in graphene and its
bilayer,‖ Physical Review Letters, vol. 100, no. 1, Article ID 016602, 6 pages, 2008.
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[12]. J. H. Chen, C. Jang, S. Xiao, M. Ishigami, and M. S. Fuhrer, ―Intrinsic and extrinsic
performance limits of graphene devices on SiO2,‖ Nature Nanotechnology, vol. 3, no. 4, pp.
206–209, 2008.
[13]. M. S. Amanda, A. Suzanne, H. Ciftan, and S. A. Olga, ―Nanodiamond particles:
properties and perspectives for bioapplications,‖ Critical Reviews in Solid State and Materials
Sciences, vol. 34, no. 1-2, pp. 18–74, 2009.
[14]. Y. Gogotsi, Ed., Carbon Nanomaterials, CRC Press, 2006.
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PLASTIC DEFORMATION ON SINTERED STEELS
BY POWDER IRON
PHD ING. Cristina Ionici
University „Constantin Brâncuşi‖ of Tg.- Jiu, [email protected]
Abstract: Deformation features were analyzed based sintered material of iron powders. They measured features
of the structure depending on the porosity of deformed iron if monoaxiale. Analiza compression results to
provide design allows physical deformation, which based on the gradual change of its dominant mechanisms to
increase porosity.
Keywords: sintered material, porosity, compression, powder iron.
1. INTRODUCTION
Use of powder materials and products in conditions of variable external loads and also
processing of powder metals claims study of mechanisms of plastic deformation depending on
basic parameters of structure [1]. In the case of powder metals the specific peculiarities of
physical mechanisms arc still not clearly understood [1-4]. In our paper influence of porosity
on behavior of deformed sintered iron were investigated.
2. MATERIAL AND METHOD
The measurements were conducted on specimens made from iron powder with the
average size of particles 80 μm. The samples were produced single-valued compact up to
required integrated porosity P and consequent thermal processing in vacuum at the
temperature T = 1450 K during 2,5 hours. They looked like cylinders of height 10-15 mm and
diameter 15 mm. The porosity P was changed from 4 to 40%. The specimens were subjected
to single-axis compression with the deformation e from 3% to fracture, for beginning of
which magistral cracks was accepted. For comparison as compact material armco-iron was
used. To the quantitative analysis of the characteristics of structure of deformed iron were
applied optical and electron microscopy. When performing the measurements, we used the
scale grid with window of 50 /tm that was laid on a polished section of the lateral surface of
the specimen. The average linear dimensions of grain Rg, average dimensions of intergrain
R.p and intragrain pores were measured. For the analysis of strain hardening the average
dimensions of mosaic block D and densities of dislocations p were determined. The
dimensions D were measured with the help of X-ray difractometer on X-ray interference
lines. The results of measurements were presented as dependences on porosity at various
fixed deformations.
2. RESULTS AND DISCUSSION
Figure la shows typical microphotos of powder iron in the undeformed state. Figure la
illustrates a role of pore as of the basic local concentrator of elastic stresses arising in material
at loading. Elastic stresses were relaxing with emitting flows of dislocations, fig. 1.
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Availability of pore are resulting by inhomogeneous distribution of mechanical
stresses. It calls significant rotational processes exhibited in turns of grain and conglomerates
of grains from each other. The given phenomenon is illustrated fig. 2.
A turn of the upper grain rather lower with creation of area of quasi-viscous current
on intergrain boundary is shown in Fig. la. The scale grid inside grains is not deformed. It
means decreasing a role of intragrain dislocation processes at plastic deformation of material
with a high porosity and prevalence of processes in the area near the boundary, in particular,
grain-boundary slippage. In Fig. 2 the turn of grain as the whole concerning it next grains is
observed. We emphasize, that in compact iron at room temperature and same deformations so
strong rotational effects are not observed.
Fig.1 Microstructure
P=0,1; ε = 0%x100
Fig.2 Microstructure
P=0,3; ε=0,3%x300
As it is visible from Fig. 2, increase of porosity much influences the average
dimension of intergrain pore, measured at fixed deformation. At increase of deformation in
case low porous material the average dimension of these pore was changed poorly.
45
40
35
30
25
20
15
10
5
0
1
2
1%
3
3-10 %
4
5
5-20 %
Figure 3. Dependencies of characteristics of structure of deformed iron on porosity
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In case high porous material the growth of deformation calls significant decreasing of
dimension Rp. It is explained by effects of extrusion of grain in pores.
In fig. 3 results of measurements of the quantitative structural characteristics are
indicated.
It testifies to necessity of the separate account of the contributions of open porosity and close
porosity at the analysis of plastic deformation of powder metals [1, 2]. Fig. 4 shows that
average dimension of grains decreases with growth of a porosity at fixed deformation. It is
stipulated by growth of dimensions and concentration of pores constraining growth of grains
at recrystallization during a sintering. In the area of low porosity the increase of deformation
calls significant decreasing of dimensions Rg on comparison with undeformed state whereas
at high porosity grains are deformed rather poorly. It is stipulated by indicated above
decreasing of a role of intragrain dislocation processes and gradual prevalence of deformation
mechanisms connected to the motion of grains as the whole.
120
100
80
60
40
20
0
1
2
1%
3
3-10 %
4
5
5-20 %
Figure 4. Dependencies of characteristics of structure of deformed iron on porosity
ε with dimension of grain.
Essential singularity of the X-ray characteristics and densities of dislocations is
nonmonotone change with growth of porosity , fig. 5. At porosities P ~ 0.1 extremum is
observed. It is brightest expressed at large deformations e. This extremum can be explained
by accumulation of significant elastic stresses on pores in conditions of rather low porosities
(P < 0.1). In these conditions relaxation of elastic stresses by grain-boundary slippage,
rotation of grains, extrusion of grain in pore is hindered. At further growth of porosity (P >
0.1) rotational mechanisms are actuating.
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0,35
0,3
0,25
0,2
0,15
0,1
0,05
0
1
2
3
1%
3-10%
4
5
5%
Figure 5. Dependencies of characteristics of structure of deformed iron on porosity:
dimension of mosaic block..
Plastic deformation of intragrain areas decreases and density of dislocation decreases
too. It is important to note, that at P ~ 0.1 the topological picture of structure is changed, just,
transition from a closed porosity to open one take place.
3. CONCLUSION
Results the essential influence of porosity in the microstructure. In case of low
porosities the plastic deformation is determined first all by intragrain dislocation processes.
At growth porosities contribution about the processes connected to motion grains as the
whole and concentrated near boundaries become stronger. At high porosities these processes
are prevalence ones
REFERENCES
[1}. M. Mangra. Metalurgia Pulberilor, Ed. Universitaria Craiova, 1999.
[2]. J. R. Moon. Powder Metallurgy, 132-139, 1989.
[3]. A. Salak . Ferrous Powder Metallurgy, Cambridge, 1995
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STUDIES ON MICROSTRUCTURE OF PREALLOYED
POWDER FE STEEL
PHD ING. Cristina Ionici
University „Constantin Brâncuşi‖ of Tg.- Jiu,
[email protected]
Abstract: The structural analysis of the powder prealloyed Fe-1.5 Mo steel in the presence of liquid phase
sintered boron, boron matrix observed a large portion of the eutectic. Impact test results showed a greater
influence for 0.4 to 0.6% B for the values of impact energy, compared with B, plus 0.2%. The character is ductile
transgranular fracture surface in samples with higher boron content there are several areas clivage.
Keywords: prealloyed, sintered boron, eutectic, clivage, powder steel.
1.INTRODUCTION
The present development trend in powder metallurgy are steels for high static and
dynamic loading. Both the microstructure character and the material density influence the
complex properties and deformation and fracture characteristics of materials.
Enhanced sintering is one of the route how to reach the high density material by pressing and
sintering only. Boron is identified as a one of sintering enhancer for iron [1], [2].
The Fe-B phase diagram shows a low solubility of boron in iron and a high solubility of iron
in boron (unipolar solubility) and also an existence of the inter metallic Fe2B which forms an
iron rich eutectic at about 1174°C.
The Mo alloyed steels are interesting as the high strength materials. Molybdenum is widely
used for alloying in powder metallurgy because of its low affinity for oxygen and solid
solution strengthening of iron. Mo stabilizes fer.rit, and by this promotes the sintering in
ferrite area. The microstructure and mechanical properties including the impact behaviour of
sintered Fe-1.5Mo-C steels were widely investigated. The enhanced sintering of Fe-Mo steels
at the presence of boron liquid phase can contribute to the properties improvement of these
steels. In this paper the effect of boron addition up to 0.6% on microstructure, impact energy
and fracture mechanisms of the prealloyed Fe-1.5Mo steel is presented.
2. EXPERIMENTAL
The prealloyed Fe-1.5Mo powder, as a basic material for the sample preparation was used.
Boron as ferroboron (Fel8B, the particle size < 0.04 mm) amounts of 0.0; 0.2; 0.4 and 0.6
mass % B was added to this powder. The specimens were compacted at 600 MPa with die
lubricant and sintered at 1200 °C for 60 min under a flowing hydrogen atmosphere.
Sintered density and microstructure analyses were carried out. The non-stan-dart specimens
(60 x 7 x 7 — 9 mm) without notch were fractured at room temperature by impact (Charpy
tester). The fracture surfaces were evaluated by SEM.
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3. RESULTS AND DISCUSSION
3.1 Density and microstructure
The green density of samples was in the range of 7.23-7.13 g cm-3. After sintering the samples
without B exhibited a density increase by 0.5%, table 1.
Table 1. The sintered density, density increase , relative density , HV 0.02 and impact energy.
MATERIAL
M
M+ 0,2 B
M+0,4 B
M+0,6 B
DS
[g/ cm3]
7,267
7,256
7,500
7,777
DI
[%]
0,51
1,42
4,71
8,00
DREL
[%]
91
91
95
98,5
IMPACT
ENERGY
[J]
55,6
51,1
18,0
14,6
M- specimen from Fe-1,5 Mo steel.
The higher densification was achieved for samples with B addition (8% increase for
samples with the 0.6% B). The basic data of sintered samples are given in Table 1.
The microstructure of plain Fe-1.5Mo steel samples is ferritic with the microhardness
values of 127 HV 0.02. Microstructure characterization of boron alloyed samples reveals a
surface zone with plain ferrit as compared to the bulk formed by new alloyed matrix. The
thickness of the external layer (1.3-0.3 mm) decreases when the boron amount rises. The
similar effect was observed also in [6] on austenitic stainless steel samples. Microstructure
shows that during sintering an interaction between matrix and B occured with the formation
of Mo boride phases in matrix grains. The microhardness values for alloyed matrix grains are
in the range of 315-283 HV 0.02 in dependence on boron addition. In samples with higher B
addition the eutectic forms a continuous network surrounding the particles which become
more spherical, moreover porosity decreases. Fig. 1 and 2 represent the microstructure of
samples with different added B.
Fig. 1. Microstructure of sintered
Fe-1.5Mo +0.2B sample
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Fig. 2. Microstructure of sintered
Fe-1,5 Mo +0.6B sample
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3.2 Impact energy and fracture
The results of the impact test showed that 0.2% B addition did not significantly
deteriorate the impact energy value compared to plain Fe-1.5Mo sample,Table 2. The higher
B content caused the lowering of impact energy values nearly by 2/3. We supposse that this
fact is in connection with the presence of an eutectic network in microstructure. The impact
energy values for samples with higher B addition.
Tabel 2 . Values of microhardness HV 0,02 and impact energy
MATERIAL
M
M+ 0,2 B
M+0,4 B
M+0,6 B
HV
ALLOYED
MATRIX
125
315
304
280
HV
SURFACE
LAYER
135
140
145
HV
EUTECTIC
1268
1200
IMPACT
ENERGY
[J]
55,6
51,1
18,0
14,6
Fig. 3 the character of surface layer. Sintered density and the microstructure was
analyses by standard sample, The fracture by Charpy impact tester were evaluated from SEM,
fig.4.
Fig. 1 Surface layer of B
alloyed sample
Fig. 2 Fracture character of
Fe-1,5 Mo sample
The fracture surface for plain M sample shows all signs of transcrystalline ductile
fracture (dimple formation caused by ductile matrix and by irregular pores, which act as
internal notches), Fig. 4. Macroscopically the failure initiation of M and M+0.2B samples
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starts by ductile mechanisms: yielding of cross-section, the crack initiation and than ductile
fracture. In the case of M+0.2B sample the ductile fracture is about 30% of the total fracture
surface. For M+0.4B sample the fracture initiation is heterogeneous - combination of ductile
and cleavage fracture. After initiation stage at about a half of cross-section the quasi-cleavage
fracture forms, the magistral crack stops and than the sample breaks. In the case of M+0.6B
did not show a visible stop of magistral crack, the yieldig of cross-section did not form, the
non stable way of fracture is dominant. The boron addition causes the increase of strength, the
decrease of plasticity and by this also the toughness is lowering. For given geometry of
samples at impact loading it is possible to consider the content of 0.4% B as a critical - the
failure mechanism is changed. The fracture surface character of samples with B addition
show.
The surface ferritic layer do not show an influence on total fracture character of Mo
alloyed samples sintered with boron liquid phase.
3. CONCLUSIONS
In conclusion the sintered of sample with boron addition caused an alloying of matrix
by boron. The higher addition B of lowered the impact energy from sample. The fracture
mechanism is transcrystalline for Fe-1.5 Mo. Boron addition causes cleavages fracture.
REFERENCES:
[1]. H. Danninger, Powder Mettalurgy, 24, 73,1992.
[2]. M. Mangra. Metalurgia Pulberilor, Ed. Universitaria Craiova,1999.
[3]. J. R. Moon. Powder Metallurgy,132-139, 1989.
[4]. A. Salak . Ferrous Powder Metallurgy, Cambridge, 1995
[5] R.N. German, Powder Metallurgy, Science, 1994.
[6] Ionici C., Studies on sintered steels under the mechanical behavior at low
temperatures, doctoral thesis, 2004 University of Craiova.
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SPARK-PLASMA SINTERING (SPS) OF VARIOUS CONVENTIONAL
AND NANOSTRUCTURED POWDERS
Associate professor. ISARIE Ilie, Drd. Ing. BOKOR Corina
University "Lucian Blaga" of Sibiu
Lecturer dr.ing. CIOFU Florin,
University "Constantin Brâncuşi" of Târgu-Jiu, [email protected]
Abstract: Aim of this study is the evaluation of the spark-plasma-sintering method and its suitability for the
compaction of various ceramic and metalic, convetional and nanostructured powders (titanium oxide, titanium
carbonitride, cooper). It should be demonstrated if this new compaction method is qualified to combine a high
sintering density with an inhibited grain-growth. The compacted samples were investigated by X-ray diffraction,
Scanning-Electron-Microscopy, Transmission-Electron-Microscopy and mettalographic methods. The results
were compared with the data obtained with conventional sintering procedures.
Keywords: plasma, powders, sintering, crystal-growth.
1.Introduction.
The problem of obtaining fully dense nanostructured bulk samples is of essential
significance in various fields of materials engineering due to their peculiar mechanical,
electrical, optical, and magnetic properties. Aim of this study is the investigation of the
sintering process of conventional and nanostructured powder samples by means of the sparkplasma-sintering method and to compare the results with conventional sintering techniques.
The spark-plasma-sintering method can be roughly compared with the conventional
hot press. Additionally a pulsed electric current is applied directly to the graphite mold. The
SPS method comprises three main mechanisms of action: a) the application of uniaxial
pressure, b) the application of pulsed voltage, and c) the resistance heating of graphite dies
and sample. Nevertheless, an exact interpretation of the microscopic effect of the SPS has not
been achieved. It is obvious that the efficiency of this method is influenced by electric and
thermal properties of the sample.
2.Experimental procedure.
Two different titanium oxide powders were used: 1) Nanophase Technologies Corp.
NanoTek titanium dioxide powder (lot number T81117-01), containing anatase, only minor
amounts of rutile, average particle size 40 nm and a specific surface area of 38 m2/g according
to data from the supplier; 2) Kerr-McGee Pigments (Germany) Tronox TR110 (lot number
0027C17) an anatase powder with an average particle size of 0,20μm.
The powder sample Titanium Carbonitride Nanopowder Lot 2002/1, from Plasma
Ceramics Technologies Inc., Latvia, was used for the compaction experiments also. this
powder was synthesized by ultra-rapid condensation from the gas phase (high frequency
plasma). Following composition was determined by chemical analysis: N7,7%;
C12,7%;O2,7%.
Two copper powder samples were used: 1) Copper MP45 from
Norddeutsche Affinerie AG Germany, and 2) Nanocopper powder from Argonide
Corporation, FL, USA. (figure 1).
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Figure 1: TEM micrographs of the investigated nanostructured powder before compaction: a) copper,
b)titanium oxide, c) titanium carbonitride; field of view approximately 1μm.
An amount of several grams of the noncompacted titanium oxide and titanium
carbonitride powders were loaded without any pressure aids in a graphite die (15 mm
diameter) and punch unit. Already precompacted copper tablets were inserted in the graphite
die. These tablets were prepared by means of conventional uniaxial pressing-avoiding an
extensive contact with the atmosphere.
Figure 2:Schematic drawing of the applied SPS apparatus.
A low internal pressure (several Pa, air) was applied at the begining of the sintering
experiment. During the sintering process the pressure increases to 300Pa while reaching
maximal temperature. The pressure applied at the punch unit reached a maximum of 7 to 15
MPa. The used electric current was typically 500A at 700oC and 800A at 1000oC. The
coresponding voltage lay between 3,0V and 4,5V respectively. The electric current was
pulsed periodically with 14 pulses/sec (2 of 14 pulses off as a recovery time).
The temperature was measured by means of a pyrometer on the surface of the graphite
die cylinder. A temperature gradient between the measured temperature and the sample is
expected. The internal pressure was controlled by a Pirani element. All parameters were
monitored during the experiment. The heating rate lay at 100oC/min, the dwelling time was 1
min. In figure 2 a schematic of this device is displayed.
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3.Characterisation.
The determination of the compacted samples was performed using Archimedes
principle, Ethanol was used as a liquid medium. The values for the relative densities were
calculated assuming a theoretical density for rutile of 4,26 g/cm3, titanium carbonitride of 5,1
g/cm3 and copper of 8,96 g/cm3. The micrographs of the uncompacted nanopowder were
obtained with a transmission electron microscope (TEM) CM 20 (Philips, Netherlands) using
an acceleration voltage of 200 kV. The microstructural investigation of the fracture surface of
the compacted saples was conducted by using a scanning electron microscope (SEM) DSM950 (C.Zeiss, Germany). The acceleration voltage was between 5 and 20 kV.
The phase characterisation of the samples and the subsequent crystallite size
determination with X-ray powder diffractometry (XRD) were performed using an Philips
X‘Pert Powder diffractometer with Bragg-Brenantano geometry using copper Ka1,2 radiation
at 40 kV and 40 mA. The measurements were performed in step-scan mode over the range 585o2‘.
For the determination of d several well defined diffraction peaks with a diffraction
angle in the range between 25o2‘ and 60o2‘ were used and an average value for the crystallite
size was subsequently calculated using Scherrers‘s equation. These data are not fully
consistent with the observed grain size in the SEM. An increasing crystallite size (XRD)
corresponds with an even larger growth of the grain size (SEM). This difference is generated
by a possible polycrystalline structure of the rutile grains.
4.Results and discussion.
Titanium oxide.
X-ray powder diffraction measurements were performed of each compacted sample to
detect the phase composition and the full width at half maximum of the diffraction maxima
(XRD-traces not displayed here. The dependency of the grain growth d/d0 as a function of the
relative value of compaction is shown. The values were obtained according to the Scherrer
formula, d0 denotes the crystallite size of the uncompacted powder
The grain growth in the conventional sintering experiments is therefore significant
higer in comparasion to SPS-samples with an equivalent grade of densification. The
activation energy of the grain-growth reaction during the spark-plasma sintering process is
significant reduced. It is most likely that the activation energy of the grain growth reaction is
reduced by spark plasma mechanism.
Titanium carbonitrude.
It ia pretty difficult to obtain dense samples of this melting material. The relative density
obtained by means of various sintering methods as a function of the sintering temperature.
Regardless of the difficulty to compare experiments of various sintering times and different
temperature measurement circumstances, the SPS process shows high densities at
comparatively low temperatures. The conventional sintering process is not capable to produce
high densities of this carbonitride sample even with comparatively long dwelling times (120
min). For the evaluation of the sinter process the dynamics of the grain growth is crucial.
The relative grain (or crystallite) growth d/d0 as obtained by XRD is plotted as a
function of the relative density for several samples. Here the SPS method can be identified by
a more favourable grain growth to density ratio.
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A compilation of all these compaction data including various parameters of the
conventional sintering experiments is given. A significant difference between the various
sintering methods can also be determined looking at the fracture surface.
The SPS compacted samples (SEM micrographs in figures 3 a) and b) show a
complete recrystallized texture with grains of various diameters between 0,3 and 5 μm with a
relative homogenous distribution around 1 μm. The few larger grains are possibly generated
by initial agglomerates in the source powder.
The titanium carbonitride sample was filled in the graphite die before the sinter
experiment without any de-agglomeration treatment as ultrasonic conditioning or mixing
under liquid phase. On the other hand the GPS compacted sample show a complete different
fracture surface (figure 4). Clusters with a grain less than 1μm size are observed in a matrix
with a glassy appearance.
The SPS method is suitable for combing high sintering densities and comparatively
low grain-growth of the titanium carbonitride compounds. Further experiments with samples
of different grain-size and different carbide to nitride ratio should be performed. The oxigen
content and the concentration of the free carbon in the various samples should also be
considered.
a)
b)
Figure 3: Scanning electron microscope (SEM) micrograph of nanostructured titanium carbonitride powder
after compaction by means of SPS at a) 1600oC for 1 min (fracture surface) and b) 1800 oC for
1 min (fracture surface).
Figure 4: Scanning electron microscope (SEM) micrograph of nanostructured titanium carbonitride powder
after compaction by means of GPS at 2100oC for 45 min (fracture surface).
Copper.
Two different powder samples were used for the compaction experiments. In each case the
preparation of this material is complicated by its oxidation behaviour. During the sintering
process the oxygen adsorbed on the surface on the copper particles and the remaining
atmospheric oxygen present in the apparatus reacts with the copper forming cuprite, Cu2O. It
should be noted that only 1% oxygen is capable forming almost 10% cuprite after complete
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reaction. The fraction of cuprite in the Argonide powder is much higher than in the MP45
sample. This could be caused by a finer grain size and a more reactive surface of the Argonide
powder.
In figure 5 a micrograph of the polished surface (optical microscopy) after SPS at
o
700 C and 800oC, respectively is given.
The fine distribution of the cuprite phase (dark grey) in the copper matrix can be seen.
Observing a larger area of the sample the homogeneity is not so well defined. The amount of
cuprite obtained from calculation from polished surface is 40% at 700oC and 57% after
sintering at 800oC, respectively. Further quantitative phase analisys of the diffraction
measurements should be undertaken.
a)
b)
Figure 5: Pictures of the polished cross section (light microscopy) of nanostructured copper after SPS
compaction at a) 700oC and b) 800oC.
Calculating relative densities with these composition, (density of cuprite of 6,1 g/cm3)
the corresponding densities are 6,46 g/cm3 (82%) and 6,29 g/cm3 (86%). The concentration of
cuprite in the MP45 samples does not exceed 5%. The SPS compaction experiments of the
copper under air show only a slight advantage compared to the conventional sintering
experiments performed under hydrogen atmosphere.
A possible application of a similar distribution of cuprite in copper has been described
in respect of the thermophysical properties of cuprite as an application for combining a
reduced thermal expansion of the copper/cuprite composite with a still reasonable thermal
conductivity. The SPS method could be a method to obtain a defined cuprite concentration
and grain size by varying the sintering parameters.
5.References
[1] Angerer P., Yu L. G., Khor K. A. – Spark Plasma Sintering (SPS) of nanostructured and
conventional Titanium Oxide powders. Mater. Sci. and Eng. A. submitted
[2] Campbell J., Fahmy Y., Conrad H. – Influence of an electric field on the plastic
deformation of fine-grained Al2O3, Metallurgical and materials transactions, 1999
[3] Ciofu Florin - Experimental research into increasing materials properties by means
depositions. 2.Cylindric surfaces -, -Scientific Conference 13th edition, November 13-14,
2009, Tg-Jiu, ISSN 1842-4856, pag.101-106.
[4] Fultz B. & Howe J.M. – Transmission Electron Microscopy and Diffractometry of
Materials, (Springer-Verlag, Heidelberg).
[5] Groza, J.R. & Zavaliangos A.– Sintering activation by external electrical field. Mater. Sci.
and Eng. A 287, 171-177.
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[6] Groza J.R. – Field activated sintering, ASM Handbook, Volume 7, 1991
[7] Holm R. – Electric contacts: Theory and application, Springer-Verlag New York Inc.
[8] Isarie C., Nemeş T., Ciofu Florin, Popescu F., - Properties and characteristics of parts
obtained by laser sintering of titanium powder mixtures., 11th International Research/Expert
Conference ‖Trends in the Development of Machinery and Associated Technology‖ TMT
2007, Hammamet, Tunisia, 5-9 September, 2007.
[9] Kamiya A. – Observation of sample sintering temperature by the plasma activated
sintering (PAS) furnace. J.Mater. Sci. Lett. 17, 49-51.
[10] Liu Z., Kovacevic R., Temperature Control Based on 3-D Thermal Finite Element
Modeling of Laser Direct Metal Deposition, Solid Freeform Fabrication Symposium, August
2-4, Austin-Texas, SUA 2004;
[11] Okamoto K., Kondo Y., Abe T., Aono Y – United States Patent Application No
2002/0145195A1.
[12] Omori M. – Sintering, consolidation, reaction and crystal growth by the spark plasma
system (SPS), Materials Science and Engineering, 2000.
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DETERMINATION OF ELECTRODEPOSITION HARDNESS BY
ANALYTICAL MODELING
PART I - Ni-P COATINGS OBTAINED BY VARYING THE ELABORATION TIME Prof. Assoc. PASĂRE Minodora Maria, University ‖ Constantin Brâncuşi‖ of Târgu-Jiu,
[email protected]
Abstract: Results obtained from Vickers hardness tests were used for analytical modeling models Buckle,
Jönsson, Hogmark. Ni-P electrodeposition were obtained by varying the elaboration time. The analytic models
obtained by theoretical means, by applying the corresponding formulas to each model have been compared to
the experimental results obtained at hardness tests.
Keywords: composite coatings, Vickers hardness tests, elaboration time, analytic models.
1. INTRODUCTION
In the literature we know several analytical models that attempted to explain
composites hardness (Buckle‘s model [1], Jönsson and Hogmark‘s model [2]). In the
presentation of models, we have used: He-measured hardness of the composite; Hf-hardness
of the film; Hs-hardness of the substrate; e-thickness of the film; δ-depth increment.
1.1. Model of Buckle
The model of Buckle [1], considers a material whose hardness varies with the distance
to the surface, the model is based on the mixing law areas. Buckle considers an arbitrary
division of the material indented by 12 layers of equal thickness to the penetration depth, D,
diamond in the material. Layer i, is involved in the hardness of all by his own hardness, Hi,
and weighted by a factor of pi, which depends on the distance of the layer on the surface, pi is
independent of material (Figure 1):
Figure 1: The empirical distribution of the weights in the sub-layers of the zone of influence of a footprint from
Buckle [1]
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The hardness of the composite, Hc, is obtained from the formula:
12
H
Hc =
i 1
12
i
p
i 1
pi
12
p
with
i 1
i
0
(1)
i
Hi, pi-respectively the hardness and the coefficient of balancing of the layer i. If the deposit is
homogeneous the coating Hf on a substrate homogeneous, too with hardness Hs, the
expression above simplifies and gives:
Hc=aHf+bHs,
with
a+b=1
(2)
or again:
Hc=Hs+a(Hf-Hs)
(3)
a- the factor of influence of the layer on the hardness measured;
b- lover integer of 12.
n
n
 pi
a=
i 1
100
p
a=
i 1
100
i
cu
n=
e
D
(4)
where:
-
n is the serial number of the last layer that is still hypothetical in the coating (n is
an integer less than 12),
- the penetration depth D,
- the film thickness e.
Thus if a = l means that the substrate has no influence on the measurement and vice versa
if a = 0. For an e/D = 10 (so in the case of a penetration depth equal to one tenth of that of the
film), the measured hardness is written Hc = 0,015 Hs + 0,985 Hf.
This expression allows to highlight the influence of the substrate is minimal, and the
measured hardness is similar to that of the film. This corresponds to the empirical rule
justified by Buckle as the "tenth rule" that one measures only the intrinsic hardness of a
deposit if the depth of the indentation is less than one tenth of the thickness of the deposit.
The main handicap of this model is that coefficients of balancing‖pi‖ are established
empirically. This model seems to be verified for close test conditions to those that have served
to the determination of balancing coefficients; it is to tell for test of indentation Vickers on
hard deposits.
1.2. Model of Jönsson and Hogmark
They proposing [2] a law of mix area to describe the hardness measured Hc:
H A H A
HC=    s s
A
A
with:
2
A
e
e
 2C    C 2  
A
 
 
198
(5)
(6)
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or again:
Hƒ =
H S  H C  H S 
e
e
2C    C 2  
 
 
2
(7)
Aƒ and AS have been respectively areas on which concentrate respectively pressure HC
and HS. A is the total area of the imprint and C a constant (figure 2).
Figure 2: Geometric model of Jönsson and Hogmark [2]
(a) areas indented in the film (Af) and the substrate (As),
(b) plastic deformation of the film that follows the shape of the indentation (C1 = 2sin ² 22 °),
(c) rupture of the film (constant C2 = 2sin ² 11 °)
According to them, the layer deforms under the imprint without thinning and the power
dissipated by the mode of deformation is localized on flanks of the imprint. In function of the
mode of deformation of the deposit under cost, one distinguishes two possibilities for the
calculation of C.
-1st case: the deposit deforms plastic and takes the form of imprinter: C1=sin2220
-2nd case: the deposit fissures: C2=2sin2110.
These authors find a good agreement between experimental results and values given by
the model for values of the report e/D understood between 2 and 3. In fact, it is necessary to
consider two cases. For a report understood between 1,8 and 2,3, the first model is the better
adapted while the second model is the more appropriate for a report understood between 6,3
and 12,9. This implies that the model is valid for a reports e/δ raised.
2. THE EXPERIMENTAL PART
The above analytical models were applied to the Ni-P electrodepositions which were
obtained by varying development time [3]. Layers were deposited on copper substrate with
different thicknesses obtained by varying development time (10-20 min) using a constant
electrolyte containing phosphoric acid (20 g/l). Hardness tests were made with variable load
(25g, 100g, 1000g, 2000g), applied perpendicular to the surface layer. Samples were noted on
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the time of development: P1 (10min), P2 (20 min). In table 1 are given the results obtained
from applying analytical models.
Table 1. Values obtained by models on deposits
Layers
P1
P2
Load
(g)
Hardness
measured
(Hv)
25
383,6
50
100
1000
2000
25
50
100
1000
2000
248,6
169,8
102,6
96,36
427
281,6
199
107,4
100,2
Hardness corrected
with Bückle model
(HV)
Hardness corrected with
Jönsson – Hogmark model
(HV)
without fissures
(Hf1)
with fissures
(Hf2)
561,84
439,64
633,63
468,51
453,17
39,8
64,9
565,54
465,57
430,42
22,6364
49,899
363,1
298,17
249,31
239
487,51
365,46
320,63
259,45
257,83
456,95
462,40
395,64
378
609,05
546,52
496,38
413,99
413,34
The results presented in Table 1 show that for small loads (25-100g) Buckle model
overestimates the hardness values obtained applying it, and for big loads of 1 kg and 2 kg,
hardness values obtained are small compared to the measured hardness for these loads,
penetrated by Vickers penetrator and obviously cracks. But these cracks were not observed
under the microscope and thus we conclude that the model does not work for large loads. By
modeling with the analytical model Jönsson-Hogmark the obtained hardness values were
much higher than the measured hardness, showing that even this model cannot be applied to
any task and any sample.
CONCLUSIONS
Application of Buckle and Jönsson-Hogmark analytical models led to obtain hardness
values totally different from the experimental results, which shows these models do not work
for any loads and any samples.
REFERENCES
[1]. H. Buckle, Use of the hardness test to determine other material properties, in: Science of
hardness testing and its research applications, Edited by J.H.Westbrook and Conrad Metals
Park, Ohio, pp.453-491, 1971.
[2]. B. Jonson, S. Hogmark, Hardness measurements of thin films, Thin Solid Films,volume
114, pp.257-269, 1984.
[3]. M. Pasăre, The time preparation influence on the electrodeposition hardness of the
composite material, part I, Ni-P alloys, Annals of the Oradea University, Fascicle of
Management and Technological engineering, Universitatea din Oradea, Mai 2012, ISSN
1583-0691, 2012.
[4]. M. Pasăre, Determination de la durete de depots NiP charges de particules SiC, Rapport
de Stage, Ecole Nationale d‘Ingenieurs de Tarbes, 2002
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DETERMINATION OF ELECTRODEPOSITION HARDNESS BY
ANALYTICAL MODELING
PART II - Ni-P/SiC COATINGS OBTAINED BY VARYING THE
ELABORATION TIMEProf. Assoc. PASĂRE Minodora Maria, University ‖ Constantin Brâncuşi‖ of Târgu-Jiu,
[email protected]
Lecturer dr. NICA BADEA Delia, University ‖ Constantin Brâncuşi‖ of Târgu-Jiu,
Abstract: Buckle and Jönsson - Hogmark analytical models have been applied to determine the Ni-P/SiC
composite electrodeposition hardness obtained by varying development time. The hardness results obtained from
the analytical modeling were compared with the hardness Vickers tests experimentally measured.
Keywords: analytical modeling , Ni-P/SiC composite electrodeposition , hardness, elaboration time
1. INTRODUCTION
The hardness of composite materials is difficult to be accurately determined. When using
small loads, fingerprint may be masked by deposit surface roughness and it cannot be
accurately determined. This problem can be avoided by two different approaches: the use of
analytical models for determining the composite hardness by hardness tests made with big
loads (both the substrate and the layer) and combining the two measured hardness or by
hardness tests with made with very small tasks ( mg) nano-hardness composite resulting.
2. THE EXPERIMENTAL PART
Ni-P/SiC composite materials were obtained keeping constant temperature, current
density, magnetic agitation, phosphorous acid (20g/ l) and SiC particles (80g/ l) content from
the electrolyte and varying development time in the range 10-20 min [1]. By application
Buckle [1,2], and Jönsson-Hogmark [3] analytical models, presented in part I of the paper, for
both PS1 and PS2 composites were obtained the values from table 1.
Studying the results in Table 1 we see that for these types of composite analytical models
Buckle, Jönsson-Hogmark cannot be applied. Hardness shaped by these models is greater for
small tasks and smaller for large tasks then the hardness experimentally obtained.
Jönsson-Hogmark analytical modeling shows that the hardness values are overestimated
for all loads and therefore even this model does not work for PS1 and PS2 composites
obtained by varying development time.
CONCLUSIONS
Application of analytical models Buckle and Jönsson-Hogmark composites obtained by
varying the development time between 10-20 minutes shows that these models give hardness
values significantly different from the experimental hardness, which indicates that these
models are not functional.
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Table 1. Values obtained by modelling for PS1 and PS2 deposits
Layer
PS1
PS2
Load
(g)
25
50
100
1000
2000
25
50
100
1000
2000
Hardness
measured
(Hv)
Hardness corrected
with Bückle model
(HV)
383,6
248,6
169,8
102,6
96,3
427
281,6
199
107,4
100,2
802,14
682,78
914,48
43,39
60,18
597,2
576,8
366
40,8
71,8
Hardness corrected with
Jönsson – Hogmark model
(HV)
without fissures
(Hf1)
with fissures
(Hf2)
611,76
495,46
412,39
342,95
388,86
693,18
789,21
629,31
249,91
355,59
955,6
803,7
678,3
575,38
665,66
603,49
608,03
481,69
312,52
334,19
REFERENCES
[1]. H. Buckle, Use of the hardness test to determine other material properties, in: Science of
hardness testing and its research applications, Edited by J.H.Westbrook and Conrad Metals
Park, Ohio, pp.453-491, 1971.
[2]. H. Buckle, L’essai de microdureté et ses applications, Publications Scientifiques et
Techniques du Ministère de l‘Air, volume 90, 1960.
[3]. B. Jönson, S. Hogmark, Hardness measurements of thin films, Thin Solid Films, volume
114, pp.257-269, 1984.
[4]. M. Pasăre, The time preparation influence on the electrodeposition hardness of the
composite material, part II, Ni-P/SiC compound, Annals of the Oradea University, Fascicle of
Management and Technological engineering, Universitatea din Oradea, Mai 2012, ISSN
1583-0691, 2012.
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ASSESSMENT ON QUALITY OF THE METALLIC
REINFORCEMENTS USED FOR SUPPORT AND SECURITY OF THE
UNDERGROUND EXCAVATIONS
Eng. PLESEA VALERIU, PhD , S.C. ICPM SA Petrosani, ROMANIA,
[email protected]
Eng. & ec. VLAICU POPA MARIUS EREMIA, PhD, SNLO Tg.Jiu, ROMANIA,
[email protected]
Eng. TOMESCU CRISTIAN, INCD INSEMEX Petrosani, ROMANIA,
[email protected]
Abstract: On the account of the advantages benefited regarding the correlation of the sliding work
regime with the specific characteristics of the predominant rocks from the lithostratigraphical structure of the
Jiu Valley’s underground, the support of metallic elements continues to represent the most advantageous version
from the technical and economical point of view.
Besides a series of advantages, including the ensuring of bearing capacity expected per meter of work
by applying the correct adopted support fields, the metallic support presents deficiencies generated by the
irrational usage of steel for machining rolled profiles, with repercussions on imperfections recorded on
element’s cold cutting and bending, including over the underground operation period of the armouring.
The target of presented paper is to analyze those deficiencies with their evaluation trough analytical
calculation and the presentation of counter measures.
KEY WORDS: Molded profiles, manganese steel, hardness, impact resistance, tenacity, elongation, heattreating, normalization, hardening and tempering.
1. INTRODUCTION
The maintaining of the optimal functionality of the underground excavation, in full
security conditions for deploying service processes for which this are destined, continues to
represent a major interest problem regarding that no matter what the reference domain is the
success of an adequate exploitation with few interventions in the maintenance expenses
chapter makes possible the framing of the economical agent in the anticipated profitability.
This is not possible yet in the case of the mining units afferent to CNH Petrosani where,
although the system of metallic support for execution of the mine galleries is introduced over
45 years and the efforts to its improvement were significant regarding the increasing of
performing quality and underground efficient exploitation in underground, the metallic
reinforcements continues to represent a problem with no universal solution, being influenced,
besides the excavation geo-mining conditions and the support constructive technical
requirements, by the quality of the machining/rolling of the molded profiles for the execution
of the component elements (the beam and the pillars).
Next will be presented some aspects regarding the quality of steels used for the
machining of molding profiles, by comparing the situation regulated by normative with the
one that existing in mining practice.
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2. QUALITY CONDITION OF STEEL FOR PERFORMING THE MOLDED
PROFILES
The general requirement for the used steel are:
- to ensure high resistance values also the material rupture to occur at high loads;
- to ensure higher values of the flow limit to imprint to the support elements a higher
bearing capacity in the elastic domain;
- to record high values of tenacity, elongation and necking so the molding elements
to support high distortion without the appearance of the rupture phenomena;
- to ensure the possibility of reusing the support elements by cold straightening,
without applying some eventual previous or subsequent heat treatments.
By economic considerations, in the last period, for machining the molded profiles are
used non-alloy steel, respectively charcoal steel type 31 Mn 4 (tip carbon – charcoal steel
type) which, in the absence of vanadium, aluminum, niobium or titanium as alloy elements,
the existing normative in force foresee the use of charcoal in proportion of up to 1,2 – 1,6 %,
and as technical principles of molding of the one scheduled by the German standard DIN
21544 – 85, according with the delivery of the molded profiles is made in a improved status
(normalized).
The steel with high carbon content, respectively the charcoal steel, namely until 0,4
%, can be characterized with resistance at stretch and superior flow limit on the account of
reduction of the deformation capacity, meaning of the tenacity, elongation and necking with
negative consequences in the mining practice.
As a result, the modern steel manufacturing is based on the using of a moderate
content of carbon (under 0,3 %), measure which leads on the obtaining of a acceptable
deformability. The trend in this case, of decreasing the flow limit, on the reduction of carbon
content, can be diminished by the presence of the alloying elements (V, Al, Ti, Ni) in the
chemical composition, and in the lack of those (the case of charcoal steel), upper values of the
flow limit can be obtained by a later appliance, after molding, of thermal treatment processes,
meaning normalization and improvement (hardening + recovery).
Application to the supplier of the thermal normalizing treatment which consists of
heating the profiles after molding at temperatures of 850 – 9000C, followed by a slow cooling
in air, leads to removal of the ferito-perlite rows structure arrangement, respectively steel
finishing and mixing, resulting high values for rupture resistance and flow limit, including
elongation.
In the case of applying the improving thermal treatment, it is recommended to be
applied after cutting and bending the support elements, of which process consists in tempering
the elements by heating at 850 – 9000C and sudden cooling in water, emulsion or oil, followed
by a high recurrence of the material, by heating at 5000C and slow cooling in air, producing
an important increase of the rupture resistance and flow limit, in the account of reducing the
elongation due to the profile‘s molded status. Also, by applying the improvement treatment is
produced the elimination of internal tensions, recrystallization and homogenization of the
harden structure which results from the cold bending process.
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3. THE QUALITY OF THE STEEL USED FOR MOLDING THE METALIC
SUPPORT PROFILES
Currently, from the wide range of molded profiles produced in the country for
manufacturing the SG support (18, 23, 29), is produced the SG. 23 molded profile, which
shape is one of gutter, produced by the e-company „Siderurgica‖ SA Hunedoara, made of
steel type 31 Mn 4 which, in lack of alloying elements, suppose an moderate addition of
carbon in the chemical content, up to 0,3 %, in accordance with DIN 21544 – 85 standard.
In reality, the molding of SG 23 profile is made by using charcoal steel with a carbon
content way over the maximum admitted limit by the type 31 Mn 4, imprinting to the internal
structure of the material an gross aspect, with an uneven arrangement and in layers of the
crystalline grains, resulting increasing of hardens and fragility on rupture, on the account of
reduction of deformation characteristics, respectively over the plasticity and resilience.
As the carbon, the charcoal content is also high, fitting in the interval of 0,81 – 1,36
%, from 0,8 – 1,1 % Mn admitted by the standards.
In contrast, the aluminum, as the only alloying element from the chemical
composition of type 31 Mn 4 steel, records low value contents, contained in the interval of
0,006 – 0,01 %, due to the imposed minimum of 0,02 % Al.
In those situations, the checking of steel‘s mechanical characteristics highlight sizes
of rupture resistance (Rm) placed over the scheduled limit, of up to 850 N/mm 2 (fig. 1), than
Rm = min. 550 N/mm2, which is explained by the excess of C and Mn, which favors the self
hardening of the profiles during the molding process, with subsequent negative repercussions
regarding cracking and breaking of the profiles when cutting and bending, especially on cold
weather.
Fig. 1. Framing mode of the steel’s rupture resistance measure depending of Carbon content
and different profile delivery statuses
In contrast, but negative, the flow resistance values (Rp 0,2 = min 350 N/mm2) and
resilience (KCU = min. 70 J/cm2) predicted by the standards for the type 31 Mn 4 charcoal
steel, are situated at a higher level than the one resulted by testing (figures 2 and 3), with
repercussions on the accentuated reduction of steel‘s plasticity and tenacity.
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Fig. 2. Framing of the steel flow limit size
(Rp0,2) regarding to the Carbon content and
different delivery status of the molded profiles
laminate
Fig. 3. Framing of the steel resilience size
(KCU) regarding the Carbon content and
different delivery status of the molded profiles
As a result of quality inconvenient of the used steel chemical content, was tried, in
the case of charcoal steel, in the lack of imposed standard thermal treatments, the reduction of
carbon content, which generated a superior resistance to flow and resilience but due to
reduction of resistance at rupture of the molded profiles, under the minimum stipulated limits,
with repercussions on the reduction of support bearing up to 20 %.
4. CONCLUSIONS
The SG.23 molding profile used for execution of the metallic support elements,
besides the inconvenient of manifestation at joints of the un-calibration phenomena, by pole
splitting and beam compression, as a consequence of joining with gaps between the shoulders,
presents the disadvantage of self-hardening during the machining process, as a result of the
used charcoal steel (31 Mn 4 type) and the lack of subsequent thermal treatment for quality
ensure, with all the adverse consequences regarding the appearance of the highly deformation
degree imprinted actually with the existent curving installations.
In order to increase the quality of machining the molded profiles become necessary
the reuse of the alloy steel (OPM type) or applying by the supplier of the normalizing heat
treatment after rolling and of the increasing one (hardening and high recovery, by beneficiary,
after curving the elements..
REFERENCES
1. Letu, N., Pleşea, V., Butulescu, V., Semen, C. – Improving the support of
horizontal works in Jiu Valley mines. Polidava Publishing House, Deva, 2001;
2. Plesea, V., Dumitrescu, I., Vlaicu Popa, M.E., Vlasin, N. - Researches
regarding the assimilation of new constructions of molded profiles and joining elements from
the component of metallic support for supporting the underground mining works. Annals of
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the ―Constantin Brancusi― University of Targu Jiu, Engineering series, Issue 4/2011, rating
CNCSIS Type B+, code 718;
3. Pleşea, V. – Constructive and fractioning improvement solution of the sliding steel
timbering for underground excavations stability. Annals of the University of Petroşani,
Mining Engineering, vol. 10, 2009;
4. Pleşea, V. – Design and construction of underground mining support works from
the coal sector. UNIVERSITAS Publishing House, Petroşani, 2004;
5. Tigaie, I., Simaschevici, H., Ridzi, M. – Analysis of the stress state in SG profiles
used for the flexible support of the galleries during the cold-bending process. Scientific
Session, University of Petrosani, 1997.
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ASPECTS REGARDING THE FORMATION CHAINS SIZES TO
SUBASSEMBLIES OF THE FIELD THE MECHANICS HEAVY
Ş.l.dr.ing. Rădulescu Constanţa
Universitatea ,,Constantin Brâncuşi‖, România
[email protected]
Abstract: In this paper we present a case study on the construction and form a chain sizes for a
subansamble of heavy mechanics. Importance training of chain size is reflected high quality for agricultural
machineries and quality of grain. Dependence of the grain crushed and which not is crushed are in function
the element closing chain size.
Key word: chain dimensions, tolerances, quality
1. INTRODUCTION
Solving chain dimensions is of particular importance in all fields of industry. By
analyzing and solving chains of sizes that are highlighted in many cases, it underlining the
importance on the design have it any machines even if the size of elements of the chain
dimensions and tolerances are very high millimeters or centimeters. High values of the
tolerances for dimensions of the components of the chain of size are found in the case
agricultural machineries, for example.
2. CONSTRUCTION A THE CHAIN OF SIZES
To understand and demonstrate the importance of constructing and solving one chain of sizes
of heavy mechanical engineering domain, it will take into discussion chains of sizes for the
distribution the bolts on drum and decks of a the combine the for cereals.
Very high
quality and economic aspects of a agricultural machinery of the type the thrasher is
characterized by its low energy consumption and very good quality grain. The research
demonstrates that the dependence of grain crushed and which not is crushed and the games
lateral is expressed by the equation [1]:
m
(1)
Y m1X R2  n1 şi Z  22  n 2
XR
unde: Y - grain not crushed in % : Z - grain crushed in %.
XR – represent lateral play between the teeth the drum and decks in mm;
m1, m2, n1 şi n2 - coefficients that depend on the type and condition the culture.
On the basis of these equations stand the fact that changing the percentage of grain
crushed and which not is crushed is expressed by:
3 2
2
Y  m1   şi Z  m2 2 2
(2)
X R X R  3 2

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where: ∆Y – represent increasing the percentage of grain which not is crushed;
∆Z - increasing the percentage of grain crushed;
σ - standard deviation of the lateral games.
Taking into account the presentation the calculus of dependency for chain of sizes,
it will determine the lateral play between the teeth of the drum and decks, if technical
requirements are established.
T
This game should not exceed XR  1,5mm .
2
The scheme the chain of sizes is shown in fig.1, where the basic dimensions of the
chain dimensions are in mm. Elements sizes chain are:
- X R represent size of the closing, lateral play between the tooth the drum and tooth the
decks;
15
 7,5mm - half tooth thickness the deck and the base her;
- X1  X 6 
2
- X 2  X 13  55,5mm - distance between the axes the holes under the studs, in the deck;
- X 3  60,25mm - distance from the edge surface up to the hole axis in the deck in the face;
- X 4  0 - error that comes from the deteriorating the deck and game into the deck and the
faces deck;
- X 5  32,5mm - error that comes from the deteriorating the deck and game into the deck
and the faces deck;
- X 7 - lateral play between the tooth the drum base and the tooth of the deck base;
6,5
 3, 25mm - half thickness of the stud (tooth)of the drum to the his height;
- X 8  X14 
2
- X 9  X 11  0 - moving the straightedge of the drum compared to circle of the drum
because of the presence of games between the part of tail studs and hole drum circle;
- X 10  27,75mm - distance between the centers of drum holes;
- X 12  0 - the beat the drum of edge.
The equation sizes chain is of the form:
ES
ES
ES
ES
ES
ES
X 2 ES
EI  X 3 EI  X 4 EI  X 6 EI  X 7 EI  X 8 EI  X 9 EI 
ES
ES
ES
ES
ES
ES
ES
  X 5 ES
EI  X 10 EI  X 11EI  X 12 EI  X 13 EI  X 14 EI  X 1EI   X R EI
For the calculation the nominal size of the resulting element will have:
X 2  X 3  X 4  X 6  X 7  X 8  X 9   X 5  X10  X11  X12  X 13  X 14  X 1   X R
55  60.25  0  7.5  0  3.25  0  32.5  27.75  0  0  55.5  3.25  7.5  0
209
(3)
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Fig. 1. The chains of sizes of distribution the studs
drum and the deck the subassembly the combine for cereals:
a) real chain, b) schematic chain.
Calculations made for tolerances that make up the chain of sizes elements is usually
an equation (k R  1) , by which, we obtain average size of the closing dimension deviations :
T Xcp
2

T XR
2  kR n

1,5
12
 0,43mm
(5)
When calculating the precision taking into consideration influence the size of error
the total change of each the constitutive dimensions of the quality indicator of assembly we
obtain accurate and correct deviations of each dimension. According to the above equation,
change ΔY and ΔZ quality indicators are expressed in standard deviation σ of side games,
to which, if deviations the component elements are similar, and their standard deviation σ are
different, then the ΔY or ΔZ increases will also be different; the different deviations of
component dimensions, but mean square deviations σ similar the increases for ΔY and ΔZ
are identical.
Consecutive, in order to establish tolerance on component dimensions of the chain of
sizes, to that each dimension error affects the indicators of quality, we should have the
standard deviation similar of their.
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But when the standard deviation is similar for the chain size elements can be
obtained in different sizes and linear deviations , and therefore the need to take into account
the proportionality coefficients determined by the relationship between field the deviation
dimension and square deviation mean of them.
3. CONCLUSIONS
The high quality of agricultural machineries on the type the thresher reflects low
energy consumption (fuel consumption) and the special quality of grain. Dependence of the
grain crushed and which not are crushed is depending on the size the side games between
teeth the drum and deck subassembly the combine.
The chain of sizes formed is complex and show that lateral play between the teeth of
T
the drum and deck should not overcome tolerance the closing element XR  1,5mm .
2
Modification ΔY and ΔZ the quality indicators are expressed in the standard deviation σ of
lateral games, in which:
- if deviations component elements are similar , and their standard deviation σ are different,
then increases for ΔY or ΔZ will also be different;
- if deviations component elements are different, but standard deviation are similar then
increases for ΔY and ΔZ are the identical
4. REFERENCES
Rădulescu Constanţa, Militaru Constantin - Lanţuri de dimensiuni. Teorie şi
practică. Editura BREN Bucureşti 2009;
2.
Дунаев, П, Ф., - Допуски и посадки. Обоснование выбора
Леликв,О.П.,
Варламова Л.Р., Мoсkва, Высшая Школа, 1984.
1.
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RESEARCH ON INCREASING ACTIVE LIFE OF CUTTING TOOLS
Alin STĂNCIOIU, University Constantin Brancuși, Targu-Jiu
Florin-Cristian CIOFU, University Constantin Brancuși, Targu-Jiu
Abstract: At the exploitation of dies the defections that occur, due mainly to non operating rules of exploration,
the improperly conditions of the machine (press) in terms of cinematic precision and the wearing elements in
relative motion (ram displacement, wearing guides, etc) as the incorrect mounting of dies on the press. When
installing dies must consider several aspects. Among the techniques used, especially for restoring the active
elements in the work area are rectified frontal surfaces, hard chromating, hardening with electric sparks and
charging welding. Were restored active profile and size of the work active elements so after reconditioning they
corresponded in terms of dimensional precision and resistance to wear, like initial elements.
Keywords: cutting, rectified, chromating, sparks, charging, welding.
1. The dies defections and remediation methods.
The wear active edges of dies depends on following factors: chemical composition and
quality of the active elements of the dies; cutting edge hardness, nature and conditions of
application of heat treatment, manufacturing process and the precision execution of active
elements, cutting edge forms, methods of greasing and lubrication, stiffness components of
dies and on assembly, semi - product cutting scheme, physico-mechanical properties of the
workpiece and the kind treatment applied to this, workpiece thickness, cutting speed, etc.
Also, the incorrectly calculated gaps can lead to the early galling and burr formation.
At the exploitation of dies the defections that occur, due mainly to non operating rules
of exploration, the improperly conditions of the machine (press) in terms of cinematic
precision and the wearing elements in relative motion (ram displacement, wearing guides, etc)
as the incorrect mounting of dies on the press. When installing dies must consider several
aspects.
In the table 1 are represented the main types of defections that can occur during dies
and molds exploration, as the methods that remedy them.
Nr.crt
Type of defection
Cause
1
Rapid blunting edges during cutting.
Inadequate heat treatment.
Processing
by correcting
inadequate active edges.
The failure of the functional
gap between the active
elements.
212
Table 1
The
method
of
remedy
Hardening by electric
sparks.
Executing a new
review of the active
elements.
Adjusting the cutting
edge of the active
elements.
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2
Rapid blunting active edges on holes
perforation.
3
Touching punch 1 of cutting edge 2.
Wrong mounting of the active
elements.
The press guide wear.
Waste entering or two semiproducts between the working
surfaces of dies.
Fixing and correct
centering of the nail
3.
Adjusting the press
gap.
Using the elements of
leading of the semiproducts.
4
Crumbled cutting edge.
The wear of the guide bushing
or
columns
because
inadequate heat tratament.
Penetration of metal waste.
The voidness bevels which
should follow the dies work.
Replacing columns
and guide bushings.
Welding load of
chopped cutting edge.
5
The puncher cracked.
The dies hole 1 is coged with
waste 2.
The heat treatment of the
matrix
was
made
inadequately.
Replace the matrix.
6
When the holes are drilling it´s
formed burr on the semi-product.
Large gaps between the punch
and the active plaque.
Should adjust the
gaps between the
active elements.
The cutting edges are
corrected.
7
Disunite(dipress) the bushing guide 2
in the end plaque or the guide column
1 in motherboard.
Scratches on the active
surfaces by entering wastes.
Replace bush guide
or column.
The scratches (small
insignificant)
are
removed by manual
rectification(abrasive
paste).
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8
Burrs at the die piece 1 to the cutting
operation.
The gap between the punch
and die is high.
The active elements of cutting
had moved.
Adjusting the gaps or
fixed the nail 3.
Cutting surfaces are
corrected.
9
The cut piece 2 is obtained concave
or convex.
The active edge of the punch 1
and the extractor 3 aren´t
adjusted.
Adjusting the front
active surfaces of the
punch
and
the
extractor (after spots
of paint).
10
The punch of drilling 1 has cracked.
The hole dies is coged with
wastes 2.
It should be replaced
the punch.
Should check the size
and the form of the
bore deviation.
11
The blunting active edge of the
punch.
The
thermal
treatment
applicated to the punch is
inadequate.
The lack of lubrication
elements in relative move.
Replace punch.
Adjusting gaps.
Proper lubrication.
12
Bending punch.
The
heat
inadequate.
Replace the punch.
treatment
is
Figures 1, 2 presents the images of the used tools viewed from the side and front with
enlarged details at 6X for tools options investigated.
Fig.1 Improved punch OSC10
214
Fig.2 Improved edge punch – 6X
OSC10
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2. Preliminary operations for reconditioning of the active tools.
The cutting tools that were used were removed from the devices, were cleaned and
degreased and have carefully studied the state of cutting edges.
The working surfaces of cutting dies, punching, bending, who had minor scratches and
worn edges were reconditioned by rectification.
The restoring active profile and the initial sizes of the work item (active) that during the
operation were blunted, broken and wasted was performed by applying a metal layer, after
which it was cleaned and rectified at prescribed dimensions on the execution design of the
reconditioned element.
Among the techniques used, especially for restoring the active elements in the work area
are rectified frontal surfaces, hard chromating, hardening with electric sparks and charging
welding.
3. The rectification of the frontal surfaces.
The working surfaces of cutting dies, punching, showing minor scratches and worn edges
were reconditioned by rectification.
The durability of dies depends on many factors such as durability itself, which is estimated
by the number of work races, or using the number of items processed between two sharpening
punch and plaque rectification of active, durability active elements of dies, estimated by the
maximum possible active race (work) until they are replaced, maximum operating dies,
estimated by the maximum possible number of races to wear it all the active elements, they
can not rehabilitate.
For calculation of cutting dies durability we used the relationship:
D pa = h/g
where:
D pa – represents the number of the active plaque reconditioning;
h – blade height active plaque;
g – the layer thickness of the removed material.
The cutting active plaque high is 3 mm, but the thickness of the away layer by rectification
is 0,3mm. Result that D pa =2,7/0,3=9.
The lifetime of the active plaque until totally wear, is determined by the relation:
D fpa = (h/g + 1)DK
In which:
D – represents the itself durability(between two regrindings) 15000 strokes;
K – coefficient reduction of the dies durability after each regrinding K = 0,9
Result that D fpa =(9+1)  15000  0,9=135000 strokes.
4. Reconditioning of electric sparks and hard chrome active of the edges.
These technologies have been presented in detail in Chapter 2, "Heat treatment applied to
tool steels".
Reconditioning by covering by spark, lend themselves to the tools with a less wear and
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reconditioning by hard chrome is used for tools with more wear.
The punch was removed from the press was opened and the die was cleaned of oil and
impurities.
For operation of hard chrome and cover spark to achieve its aims, it was necessary
rectified the used areas, removing the tread and the wear, so that chromium deposit to be
uniform.
Deposited layers had equal depth of the cavities of edge tools, and hardness were for spark
covered layer 755HV and 720HV for chrome layer.
5. Reconditioning by welding load.
Reconditioning by welded load is performed to increase wear resistance and toughness
loading dies and consists in working load edges of the active elements. Shown below
reconditioning technology by welding a steel punch of OSC10 improved.
Before reconditioning punch was annealed for regeneration to change the structure of the
constituents most compatible with welding. After regeneration, before starting the welding
operation, process by pressing in active tool in the worn zone a hole and then preheated to a
temperature of 550oC.
Later, the cavity was filled with weld by superposed layers. After loading the weld the
piece was subjected to a normalization treatment. After adjustment followed by heat
treatments of burning and tempering to correspond to hardness before Reconditioning,
followed by rectification prescribed profile. Final hardness was 61 HRC.
For charging welding electrodes were used 100CrMoV type. Welding operation was done
with device continuous current with short arc reverse polarity, that the piece was connected to
the negative pole and the electrode to the positive pole, this connection avoiding overheating.
The current intensity loading of the weld was 130 A, electrode diameter was 3 mm. The
reconditioning by charging weld,the electrode was held at an angle position after contour
waste area. However, to avoid cracks in the deposited layers, the core material was heated to
annealing temperature softening and maintained in the temperature range 450 ... 550 C (to
ensure maximum stability of austenitic constituent).
After loading the welding operation followed the operation for adjusting the active
elements after template for the smooth functioning of the dies. Adjustment of active edges
was done after template at paint with a hand grinder, fitted with abrasive wheel of 46 grain.
For final adjustment were used grinding wheels with different profiles, with a granule size 4680 from synthetic corundum (electro-corundum) and bakelite binder.
After rectification with abrasive stone were cleaned asperities. The direction of movement
of the abrasive stone was constant, for keeping active geometry.
Fixing surfaces were adjusted to the paint, after die cutting the semi around 600. After
finishing the adjustment operation,the die sat again on the press for the settlement. Figure 3
presents a macro picture of the steel punch OSC10 reconditioned by welding.
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Area refurbished by welding
Fig.3 Die OSC10 refurbished by welding
6. Concluzions:
By applying reconditioning was increased the indicators so implicitly durability of cutting
tools.
Were restored active profile and size of the work active elements so after reconditioning
they corresponded in terms of dimensional precision and resistance to wear, like initial
elements.
The condition of the active elements was verified after dimensional accuracy and form of
the last pieces punched which was classified as tolerances and technical design requirements
of its execution.
References
[1] Stăncioiu Alin, Cercetări cu privire la influenţa calităţii sculelor asupra proceselor
tehnologice de tăiere, Universitatea din Craiova, Teza de Doctorat, 2004
[2] Şontea, Sever., Tratamente termice şi termochimice, Editura Spirit Românesc, Craiova,
2001
[3] Şontea, Sever,Metale şi aliaje neferoase de turnătorie, Ed. Scrisul Românesc Craiova,
1981
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AN ANALYSIS OF THE MANUFACTURING PRODUCTIVITY
WHEN THE SAME PIECE IS PERFORMED ON 3 VERSUS 4 AXES
MACHINING CENTERS
Alexandru STANIMIR, Catalin ROSU, Cosmin MIRITOIU,
Dumitru PANDURU, Emil PATRU
University of Craiova
email: [email protected]
Abstract: In this paper two technological manufacturing variants of a part are presented, one for
fabrication on a vertical manufacturing centre with 3 axes YMC type and another one for fabrication on a
horizontal manufacturing centre with 4 axes MCM type. The numerical control programs for the two
manufacturing centers were made by using the CAD and CAM modules from the TopSolid software. The
necessary times for doing the manufacturing were determined by their simulation, and by clocking the
fabricating time of the products on the machines. After the analysis, there has been found for this case of study
that, although there have been used the same cutting tools with the same cutting conditions, the higher number
of fixings is not the most important factor for decreasing the productivity.
Key words: manufacturing centers, productivity, simulation, TopSolid
1. Introduction
The manufacturing centers with numerical control are technological equipments with a
high productivity and precision that make possible special achievements. The advantages of
these machines in relation with the universal ones are expressed in productivity terms,
precision, shape complexity, manufacturing cost or the flexibility at the product change[1,4].
These advantages are due to the numerical control, the high number of machining operations
that can be made at a single fixing of the product, the automatically changing of the cutting
tools, the fast and accurate positioning of the cutting tools in relation with the workpiece etc.
It is well known that, for products with difficult configuration, with a high number of
machining that must be done and with a high number of cutting tools in several different
fixings, the manufacturing centers are several times more productive than the classical
machines. The price difference of a product manufacturing increases with the complexity of
the machined surfaces geometry.
A milling manufacturing centre is the result of the adding at a milling machine of a
storage hopper provided with an automatically system for their change and other devices for
their handling. There are more manufacturing centers types, the number of programmable
axes, the main shaft position etc. make the difference between them.
Other examples show that the shapes complexity that can be made and the machine
price increase with the increase of the control axes number [4,5].
In this paper we want to analyze the technological changes that interfere in the
practical case of a part performing on two different manufacturing centers and their
implications in the manufacturing time. To make this analysis, the TopSolid software for
manufacturing simulations was used, and for validation, a group of 25 pieces were performed
on the horizontal manufacturing centre with four axes MCM and also on the vertical
manufacturing centre with three axes YMC1050.
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For these technological equipments choosing, there has been considered that for the
manufacturing centre MCM type, the product can be obtained at a single fix in the device, and
after manufacturing only the surface, that contain the connection with the product, finish
machining must be made, and in the case of YMC manufacturing centre the piece obtaining
assumes more fixings.
2. The used method and equipments
In this study we have considered a piece made from aluminum alloy 6082, whose
surfaces can be obtained on the horizontal manufacturing centre MCM with four axes [11],
and also on the vertical manufacturing centre with three axes YMC1050 [12].
The 3D piece model was made with TopSolid Cad, and the TopSolid Cam was used
for simulation and for performing of numerical control program [6, 7, 8, 9, 10].
To establish the manufacturing time, a group of 25 pieces were considered, and in
order to easily compare the results, the same cutting tools set and cutting conditions were used
for both machining centers.
The necessary normalized time for the piece fabrication, tn, has two components: one
named unitary time tu, which is consumed at the fabrication of each piece, and another one
that consumes one time for all the n pieces from the group named as the preparing-finishing
time tpi. Between these terms there are the relations [2, 3]:
t pi
t pi
t n  tu 
 top  tin  tdes 
[min]
(1)
n
n
where top is the operative or effective time, tdes is the attendance time and tin is the time of
working disengage, all these times correspond to a product fabrication. In our case, the
manufacturing is made in a semiautomatic process, and according to [2] we have:
top  tbm  t g  ta  tm  ta [min]
(2)
where tbm= machine base time, tg= is the no load running time (tm=tbm+tg time for machine
manufacturing) and ta= auxiliary time consumed by fixing the product on the machine. If tdes
and tin are neglected, from the relations (1) and (2) results the calculus relation of the
normalized time necessary for the product fabrication:
t pi
[min] ,
(3)
tn  tm  ta 
n
respectively for the whole group of pieces:
tlot  n(tm  ta )  t pi [min] ,
(4)
The indicated times from these relations are determined in this way:
tm – is read from the CN console or is determined by simulation with the TopSolid Cam
module;
ta- is determined by clocking or with the time normative;
tpi- is established as a times sum for: cutting tools mounting in the tools holder and their
measurement in the presetting device (fig. 1), the cutting tools mounting in the storage hopper
and the panel insert of the length and radius corrections t2, and, finally, considering the
workpiece origin and inserting its coordinates from the from the CN panel t3.
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3. Part modeling
The chosen case study in this paper refers to the modeling of a part that requires the
use of the main features of Design module like points, circles, sketch lines, curves, offset
contours, axis and coordinate system in the sketch mode and extrude, drilling, boring, tapping,
fillet, chamfer and propagate operation in shapes mode. Also the shape of chosen part
assumes the use of the main manufacturing processes that usually may be met on a machining
center.
The 3D model of the product is presented in figure 2, where we made a surface
numbering which will be used to identify the performed surfaces at each manufacturing
operation.
Fig. 1 - Tool's presetting
Fig. 2 - The part model
4. Horizontal manufacturing centre MCM programming
The manufacturing centre MCM-Z16 is provided with an exterior paddles system
where the stock can be fixed in device and prepared for the next work without interruption of
the current running process. The platen degrees of freedom allow the machine loading with
many products, different of identical, that can be successively manufactured, and its using as a
machine with four axes for complex shapes fabrication with a single fixing, resulting a high
degree of the manufacturing precision.
For TopSolid Cam modeling we have firstly choose the machine and the clamping
device (fig. 3), where the workpiece was loaded and finally the origins were performed (fig.
4).
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Fig. 3 –The machine with the fixing device
Fig. 4 – Stock and origins
At each manufacturing operation, the cutting tools, the tool holders and the cutting
conditions were chosen. For example, at the first operation where we have made the roughing
cut of the side surfaces 5 and the contour 9 (fig. 8), we have chosen a mill with a 63 mm
diameter and the adequate tool holder (fig. 5 and 6), after this we have established the cutting
conditions (fig. 7).
The provided manufacturing operations and the cutting tools which were used to
perform those operations are presented, in the run order in the table from fig. 9. The numbers
from the first column refer to the cutting tools position in the storage hopper. Also this table
contains information regarding the cutting conditions, the number of the cutting tools teeth
and the cutting tools corrections that must be inserted from the machine panel (columns D and
L).
Fig. 5 – Tool type choice
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Fig. 6 – Linked tool choice
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Fig. 7 - Cutting conditions
Fig. 8 – First operation simulation (machining mode)
The product surfaces were programmed to be manufactured in this way:
Op.1 – rough milling of no. 9 and 5 surfaces (left-right) with the no. 1 cutting tool;
Op.2 – three holes centering for the no.1 and 7 circular bores with no. 2 cutting tool;
Op.3 – drilling of no. 7 surface with no. 3 cutting tool;
Op.4 – rough milling no. 9 and 11 surfaces with no.4 cutting tool;
Op.5 – rough milling no. 6 surface with no. 5 cutting tool;
Op.6 – finishing milling no. 6 surface with no. 6 cutting tool;
Op.7 – chamfering no. 8 surface with no. 7 cutting tool;
Op.8 – finishing milling no. 9, 10, 11 and 2 surfaces with no. 8 cutting tool;
Op.9 – drilling no. 1 surfaces with no. 9 cutting tool;
Op.10 – threading no. 9 surfaces with no. 10 cutting tool;
Op.11 – finishing milling surfaces 3 and 5 (left-right) with no.1 cutting tool;
Op.12 - spreading no. 7 surface with no. 11 cutting tool;
Op.13 - boring no.7 surface with no. 12 cutting tool;
Op.14 – milling separation surface no.4 with no. 4 cutting tool;
The no. 2, 4, 5, 7, 8 si 14 operations are made at two workpiece orientations, and for
the operation 1 are necessary three orientations.
The list of the used cutting tools with the part handing scheme and the cutting tools
sets made in TopSolid Cam and used at their setting, are presented in figures 10 and 11.
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Fig. 9 – List of operations
Fig. 10 – Part handing schema and origins
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Fig. 11- Setup of the used tools
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Fig. 12 – Simulation into machine mode
Fig. 13 – Checking tolerances
After the manufacturing simulation in the machine mode, at the last operation the
products looks like the one presented in fig. 12, and after the tolerances validation (fig. 13) it
is observed that on the no. 4 surface has been left a machining allowance.
5. Vertical manufacturing centre YMC programming
For the product execution on the vertical manufacturing centre with three axes YMC
1050, three fixings in the vice were provided, at the last fixing was used a device for
workpiece orientation.
At the first fixing the surfaces 3, 4, 5 (left side), 6, 7, 8 (left
side), 9, 10, 11 were completely manufactured. The way for making the first fixing on the
machine and the origin choosing is shown in figure 14. Into figure 15 is shown the milling of
the piece contour.
Fig. 14 – Stock and origins
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Fig. 15 – Contouring simulation
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At the second fixing, the remained material is removed on the surface no. 5 (right side
fig. 16) and a circular bore chamfering is performed (fig.17).
At the third fixing, the surfaces 1 and 2 (fig. 18 and 19) are performed by milling,
centering, drilling and threading. The detail from fig. 18 shows that the product orientation is
made on a vertical planar surface, a short plug that enters in the piece circular bore (no. 7
surface) and a supporting plug with which the product comes in contact through the no. 3
surface.
Fig. 16 – Stock and origin
Fig. 18 – Stock in device and origin
Fig. 17 – First operation simulation
Fig. 19 – Last operation - threading
On the vertical manufacturing centre was used the same cutting tools set, with the
same cutting conditions as in the case of the fabrication on MCM machining centre. The tool
holders obviously are those that correspond to the YMC 1050 machine, BT 40 type. Their
selection was made according to the exemplification from the figures 5..7. There were also
realized the operations and the used cutting tools lists like in figures 9..11.
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6. Results analysis
The times involved in relation (4), determined on each considered case, by the
manufacturing simulation with TopSolid, or by clocking of the consumed times with the
practical fabrication of the products, in the both variants of manufacturing on the two
manufacturing centers MCM and YMC, for each fixing P, are written in table 1.
Table 1
MC
MCM
YMC
P NT
1
1
2
3
12
10
(2)
2
t1
[min]
48
40
0
8
t2
[min]
15
10
0
3
t3
[min]
15
10
10
10
tpi
tm
ta
[min] [min] [min]
78/30 23,13
0
60/20 12,53
1
10/10 1,23
1
21/13 2,01
1,5
tlot
[min/h]
608,25/10,14
358,25/5,97
65,75/1,10
100,75/1,68
In the table 1, the NT column contains the number of the cutting tools used at each
fixing. At the fixing number two on the manufacturing centre YMC, the two used cutting
tools are written between parenthesis because they were also used for the first fixing, reason
for which the t1 times, for the cutting tools montage in the tool holders and their measurement
in the presetting device, and the time t2, for the cutting tools montage in the storage hopper
and the panel insert of radius and length corrections, are zero.
By summing the consumed times at the three fixings considered for the manufacturing
made on the vertical centre YMC, is obtained: t1=48[min], t2=13[min], t3=30[min],
tpi=91/43[min], tm=15,77[min], ta=3,5[min], tlot=524,75[min].
700
600
time (min)
500
400
300
200
100
YMC-3axis
0
Tpi
Tm
MCM-4axis
Ta
Tlot
Fig. 20 Times to achieve 25 pieces on MCM and YMC machining centers
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From the table 1, we can see that, although on the MCM manufacturing centre the
pieces are fabricated at a single fixing, and the fixing and removing time is zero, overlapping
on the manufacturing one, however the necessary time for obtaining 25 pieces is higher than
in the case of YMC manufacturing centre.
For a more significant showing of the analyzed situation, with the determined values
for the different classes of the involved times, there was built the diagram from fig. 20.
Conclusions
From the two manufacturing technological variants analysis of pieces on the
machining centers MCM and YMC, presented in this paper we can extract the following
conclusions:
- The total necessary time for making the 25 pieces is higher in the case of the vertical
machining centre with 4 axes;
- Although both manufacturing centers work with the same set of cutting tools, the preparingfinishing time is higher at the vertical manufacturing centre with 3 axes YMC 1050, which
performs the pieces at three fixings, unlike the MCM where the manufacturing is made at a
single fixing;
- The consumed time with the fixing and removing of the products is zero for the MCM,
which allows the product fabrication at a single fixing, the fixing and removing time
overlapping on the manufacturing one;
- Although both machines work with the same cutting tools set and use the same cutting
conditions, the time in witch the pieces are manufactured on the machine is higher in the case
of MCM, the main causes could be: the lower stiffness of the product fixed in the device, a
reason for what there were established an extra number for finish machining, the necessity for
making a high number of product orientations, and, not least the outlining manufacturing
accomplishment in distinct operations in order to make the product at a single fixing.
References
[1] Ciocardia. C., sa., Bazele elaborarii proceselor tehnologice in constructia de masini,
Editura didactica si pedagogica Bucuresti, 1983;
[2] Draghici. G., Bazele teoretice ale proiectarii proceselor tehnologice in constructia de
masini, Editura Tehnica, Bucuresti, 1971, pp.261-263;
[3] Popescu. I., sa. Tehnologia fabricatiei produselor mecanice, vol.1, Editura MATRIX
ROM, Bucuresti, 2005, pp348-350;
[4] Stanimir.Al., Tehnologii de prelucrare pe strunguri cu comanda numerica - Operare si
programare, Editura Universitaria, Craiova, 2002;
[5] Stanimir. Al., Panduru. D., Mâşu. B., Rusu. F., Popa. C., Programing a 3 axes machining
centee with TopSolid - Part II - G-Code programme creation , International conference of
mechanical engineering ICOME 2010, 27-30 apr. 2010, Craiova;
[6] TopSolid Quick references, Missler software
[7] TopSolid’Design 2006 - Training Guide, Missler software
[8] Top Tool, Missler software
[9] TopSolid’Design 2007, 2008, 2009 – What’s New, Missler software
[10] TopSolid’Cam 2006 - Training Guide, Missler software
[11] http://www.exapro.com/mcm-connection-z16-horizontal-machining-centre-pe112484/
[12] http://www.young-tech.com.tw/ymc1050.html
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CONTRIBUTIONS FROM SMOKE ON IMPACT OF WELDING
PROCEDURES HEALTH OPERATORS WELDER
Dr.ing.Gheorghe AMZA, Dr.ing.Zoia APOSTOLESCU
Drd.ing. Maria Dragomir GROZA, Drd.ing. Liana Sanda PAISE
Polytechnic University of Bucharest, [email protected]
Abstract: This paper presents research conducted on the contents of fumes resulting from welding processes with
emphasis on micro various metallic and nonmetallic elements involved in these fumes. It also presents the main
health effects of welders and operators working in the welding stations. Are risks that may occur due to micro
chromium, nickel, iron, manganese, silicon, fluorine, zinc, aluminum, copper, cadmium, lead, molybdenum,
cobalt, vanadium and others.
Keywords: impact, smoke, welding on health.
1.INTRODUCTION
There are several reasons for the welding operation is considered a dangerous occupation,
namely:
- Are a multitude of factors that endanger the health welder, such as heat, radiation, burns,
noise, smoke, gas, electric, and even uncomfortable places where this type of work takes
place (closed tanks, ships, etc. way .);
- High variability in the chemical composition of smoke resulting from welding, the welded
piece
varies
according
to
the
method
used
and
the
environment;
- Effects on their fumes and gases resulting from the welding operation on human operators.
Harmful effects caused by the welding operation from chemical, electrical, physical,
mechanical
and
technological
radioactive
accompanying
this
operation.
Risks that are subject to human operators acting in the workplace are presented in Table 1.
Common chemical hazards include metal particles and gases.Physical risks are the power,
noise, heat and vibration.Electromagnetic radiation waves appear visible, ultraviolet, infrared.
Welding operation is associated with a number of risks in terms of respiratory health
problems. The most common risks are the effects of electricity, heat and electromagnetic
radiation. Ultraviolet light is produced by an electric arc welders and often cause eye
problems. However, particles and gases generated during welding are considered more
harmful than other results of the welding process.
2. FUMES RESULTING FROM OPERATIONS WELDING AND THEIR EFFECTS
ON WELDER
Smoke refers to solid metal suspended in air that are formed when vaporized metal condenses
into small particles (smaller than 2μm). Metal vapor oxidizes when in contact with oxygen in
the air so that the major components of smoke are metal oxides used to make wire welding
electrode that is consumed.
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Smoke
(microparticules)
Aluminum
Cadmium
Chromium
Copper
Fluorine
Manganese
Molybdenum
Magnesium
Nickel
Silicon
Titanium
Table no.1 Sources of risk for operators welders
Gas
Radiant energy
Other risks
Carbon dioxide
Carbon monoxide
Nitric oxide
Nitrogen dioxide
ozone
Sulfur dioxide
Sulfur oxide
Oxides of other metals
ultraviolet
visible
infrared
ionized
heat
noise
vibration
electrocution
burns
Zinc
Some metal constituents of welding fumes may result in greater risks than others, depending
on their inherent toxicity. Fumes resulting from welding operations may be due or may
contain a number of chemical elements as follows:
2.1. Microparticles of chromium.
Chromium may be present as a layer on the workpiece to be welded, generally stainless steel
and the welding electrodes containing chromium steels.
Chromium is found in smoke resulting from welding of stainless steel and is an irritant of the
nasal tissue. Exposure to fumes containing high concentrations of soluble chromium during
welding of stainless steels in enclosed spaces can be a potential of causing acute or chronic
chromium poisoning that can cause asthma and dermatitis.Epidemiological studies and animal
tests have confirmed that certain chromium compounds are carcinogenic. These health risks
have been determined for non-welding operations. Qualified welders TIG process, a
procedure used mainly for welding stainless steels are exposed to much lower concentrations
of chromium than the welders using the manual arc welding and coated electrode (SMEI).
2.2. Nickel microparticles. Nickel is present in the smoke resulting from the combination of
stainless steels and nickel alloys. Nickel is classified as carcinogenic to the human operators.
Inhalation of nickel compounds cause lung cancer. It seems that there are significant
differences in the potential carcinogenicity of various nickel compounds. Studies indicate that
stainless steel welding fumes resulting from nickel mutagenic potential. Epidemiological
studies suggest that stainless steel welders have an increased risk for developing lung cancer
due to nickel.
2.3. Microparticles of iron. The main component of fumes generated from welding processes
is most iron oxide. This is considered a powder with a small probability of causing a chronic
disease of the lungs after inhalation. However, microparticles of iron oxide accumulates in the
interstices of the lung. When present in certain quantities deposit is visible when x-ray
radiographs As a result, long-term exposure to tobacco use in welding arc lead to
pneumoconiosis among welders as well as siderosis.
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2.4. Microparticles of manganese. Manganese is present in most fumes
results in the welding process and is also a cytotoxic and neurotoxic substance. Manganese
oxide is used as a feed to cover the electrodes used in manual welding Submerged arc welding
as an alloying element in steel development. Resulting from exposure to welding fumes
containing manganese steel can lead to acute inflammation of the lungs.
Some special types of steel containing a high percentage of manganese can produce high
concentrations of manganese oxide smoke. He hypothesized that exposure to smoke resulting
from the welding operation can cause diseases like Parkinson's disorder.
2.5. Silica microparticles. The main source of silicon in smoke resulting from the welding
process, comes from coating metal electrodes and the composition flow Submerged arc
welding. Or flow coating containing a large amount of silicates (5 ... 30%) and silicon, ferrosilicon, talc or water glass. Silicon found in smoke resulting from the welding operation is in
amorphous form that is non-cytotoxic and can be highly cyto-toxic if found in crystalline
form.
2.6. Microparticles of polymer. Major source of fluoride in the smoke appears in the
welding electrode coating comes from manual metal arc welding or flux and slag composition
for Submerged arc welding or slag bath.
Electrodes coated low hydrogen electrodes in arc welding contain a large amount of calcium
fluoride. Inhalation of gas containing fluorine, has been shown to affect the lungs (Stavert and
others, 1991), and pulmonary exposure to fluoride particles involves a risk factor for
occupational lung diseases. Previously demonstrated that smoke resulting from SMEI,
causing several injuries and inflammation of the lungs than fumes resulting from welding by
MIG. In addition, inhalation of fluoride affect anti-bacterial defense mechanism of the lungs
which can increase the likelihood of infection.
2.7. Microparticles of zinc. Exposure to zinc welders, most often comes from galvanized
coating of metal to be welded. Zinc fume fever due welders occurs when galvanized metal is
heated sufficiently to vaporize zinc, thus creating a smoke with a high content of zinc oxide.
Due to zinc fume fever is most often described as an acute respiratory illness of welders.
Symptoms occur at 6 ... 8 hours after smoke inhalation and is characterized by symptoms of
influenza, a sweet sensation, excessive thirst, high fever and dry cough. Chronic disease
expire after 24 ... 48 hours after inhalation and treatment.
2.8. Microparticles of aluminum. Aluminum is often used as an additional element in many
steels and alloys present in welding electrodes. Aluminium is also present in coatings such as
paint, applied basic electronic or spray. Common practice MIG welding of aluminum alloys
using aluminum wire for added magnesium produces a relatively high smoke the ease with
which magnesium vaporize. Also, aluminum welding leads in particular to produce toxic gas
called ozone.
2.9. Copper microparticles. High levels of exposure to copper fumes are possible when
welding copper or copper alloys. Another source is copper from copper wire in MIG / MAG
and submerged automatic welding flux. Copper is one of the metals vaporized causing
welding fume fever (Sferlazza and Beckett, 1991).
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2.10. Cadmium microparticles. Cadmium may be present on the surfaces of certain metals
to be welded. Cadmium oxide smoke inhalation may cause respiratory irritation and acute
bronchitis, pneumonia and chronic occurrence of excessive fluid in lung tissues (pulmonary
edema). There may be a latent period of several hours after exposure and before symptoms
appear. Effects of overexposure to cadmium can lead to initial fume fever. A single exposure
to high concentrations of cadmium oxide welding fumes can be fatal. Chronic cadmium
poisoning can cause serious damage to lungs and kidneys and is similar to nicotine poisoning.
2.11. Microparticles lead. Potential lead exposure occurs during welding or cutting any
metal coated or painted with lead based paint lead. Lead poisoning is rare among welders, but
can occur in people involved in the process of cutting metals coated with lead-based paint
such as for dismantling or demolishing bridges boats. Lead poisoning, which occurs among
welders exposure to lead oxide from welding smoke can affect the blood, tissue, gastro intestinal and nervous system.
2.12. Microparticles of molybdenum. Molybdenum is the alloying element in
steels. It was found that smoke containing molybdenum can cause bronchial irritation and
kidney and liver.
2.13. Microparticles of cobalt. Cobalt is a component found in some
alloys that can withstand high temperatures and must have also a high hardness. Researches
have shown that inhalation of fumes containing cobalt may cause decrease respiratory rate,
coughing and pneumonia.
2.14. Microparticles of vanadium. Vanadium may be present in some filler material and
some special alloy steel. Exposure to vanadium oxide of carbon, especially vanadium
pentoxide (V2O5) gives rise to severe irritation of the throat and respiratory system and cause
chronic pneumonia.
2.15. Silicate microparticles. Silicates and silicon dioxide formed in the welding fumes
results are amorphous and are deemed less offensive, but recent research has highlighted the
nervous and respiratory irritation.
2.16. Microparticles fluoride. Welders can be exposed to fluoride dust, smoke and fumes
resulting from the fusion welding processes. Fluoride in fumes can irritate eyes, throat,
respiratory system and skin. Fluorosis is a syndrome characterized by increased deposition of
fluoride in bone density and ligaments.
2.17. Microparticles of other metals. Welding process produces fumes and other metals
such as mercury, magnesium, titanium, tungsten and tin. Within the limits of available
information was not reported any effect on health due to smoke that occurs in the welding of
these metals but under certain conditions, zinc, mercury and magnesium give rise metal fume
fever or other respiratory irritation.
Beryllium is a volatile and toxic components that may be present in many welded alloys of
copper, but is the form itself. Beryllium oxide in the smoke is very toxic to the respiratory
system, lungs and skin with a quick response. Beryllium is suspicious about the occurrence of
cancer in welders.
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3. SMOKE WHEN WELDING PROCESSES.
Smoke resulting from certain welding operations is an extremely complex product. SMEI
welding smoke is produced by vaporization metal core and shell components of the electrode.
A variety of constituents of the electrode coating reacts to high temperatures arc producing
carbon particles containing a complex mixture of oxides and other components.
Factors that cause reactions due to core melt and melt flow components are:
- Welding conditions that influence the arc and gas temperature;
- Relative volatilities, representing the character of vaporization of metal oxides;
- Thermochemical factor.
In some cases, in addition to welding consumables, and other materials can be an important
source of contamination of the atmosphere such as:
- When the song contains volatile constituents such as beryllium copper;
- When ferrous metals have oxide coatings or the non-ferrous metals such as copper and
nickel and their alloys are heat cut, heated and welded;
- When parts are painted, paint fumes arising due to pigments and organic pollutants in
cement paint.
3.1. Smoke production from certain welding processes. As a benchmark, it may be noted
that for arc welding processes, welding Submerged arc automatic (SAF) has the lowest rate of
formation of smoke.
If welding process in protective gas, the situation in which carbon dioxide is used as a
shielding gas results in a higher rate of formation of smoke than when using argon or helium
as a shielding gas. Oxygen or carbon dioxide gas when added to the patron have a stabilizing
effect on the arc, but their addition leads to an increase in the occurrence of smoke. However,
small amounts of carbon dioxide, argon or helium with give rise to a voltage transfer with low
spatter arc, accompanied by some loss by splash and a lower rate of formation of smoke.
Grinding and sanding are known as two methods that generate large amounts of smoke and
dust. SAF welding, dust can be a problem, being caused by handling flow, but there was no
open arc of smoke and gases generated problems are minimal.
The amount of smoke resulting from cutting or welding plasma is generally higher than that
resulting from protective gas welding environments. microwelding and special welding
processes such as friction welding, electron beam welding and laser welding generates small
amounts of smoke.
3.2. Formation rate and composition of smoke.
The rate of formation of smoke and its chemical composition as influenced by welding regime
parameters and application type. Below are listed the most important factors, whose
participation has been shown to influence the rate of smoke formation and its chemical
composition as follows:
- Voltage of arc welding which depends on maintaining its length;
- Polarity, that is, direct and reverse AC and DC;
- Welding current;
- Angle between the electrode and the welded part;
- Position and type of welding;
- Arc temperature, which is directly related to power and inversely proportional to the speed
arc welding.
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Fume formation rate varies according to arc length, which in turn can be influenced by
experience welder. In general, experimentally found to increase with increasing fumes
welding current, voltage and arc length increase.
3.3. Micro size smoke. Micro size carbon is less than 1 μm, which means it is 0,001 mm in
diameter, but when they occur, tend to increase in size due to congestion, meaning the union
of two or more micro. Particles with sizes between 1 ... 7 μm occur over time. Particles with
sizes of 1 ... 7 μm is the biggest health threat because of their ability to penetrate deep inside
the lungs. Visible particles of smoke are usually the heaviest particles, which will precipitate
rapidly on adjacent surfaces and are known collectively as "dust fall". Particles in the
breathing zone of welders are usually the size of 2 mm, or less, these fine particles can remain
lower for several hours in the air if not removed by ventilation.
Data presented in the literature were obtained from tests performed:
- In carefully controlled environments;
- During the current employment conditions;
- In laboratories, thus being able to shape the conclusion that the severity of exposure to
welding fumes vary due to differences such as the welding process and materials used, time of
exposure, ventilation in the exposure, the time between welding and measurement function
lung and used protection.
Also, the researcher Stern (1981) indicates three other factors that lead to effects on lung
function occurred. One factor is population dynamics, which may encourage the selection of
its own among welders who experienced respiratory problems to choose another profession.
The second is the effect of smoking on lung function. Some studies indicate that effects on
lung function are related and that some welders are smokers (Hunnicutt and others, 1954;
Cotes and others, 1989, Chinn and others, 1990). The third factor is the effect of the witness.
Many welders are employed in places known to be a high risk of chronic lung disease. Thus,
pulmonary function test results may be related to exposures other than welding smoke at
work.
After a careful analysis of the literature, researchers Sferlazza and Beckett (1991) indicates
that none of the studies that evaluate lung function of welders suggests that daily exposure to
welding adversely affects lung function. Most studies show minor effects to sensitizing of
welding on lung function (Oxhoj and others, 1979, McMillan and Heath, 1979; Keimig and
others, 1983). Studies over the welders in shipyards, which are exposed to more smoke
conditions, due to work in confined spaces, poorly ventilated, shows negative effects on
pulmonary function compared with those welded in open spaces well ventilated (Oxhoj and
others, 1979; Chinn and others, 1990, Akbar-Khanzadeh, 1980, 1993).
Mur and others (1985) have shown that welders working in confined spaces have a reduction
in
lung
functionality
versus
those
working
in
well-ventilated.
Many studies have attempted to determine if welders experience chronic asymptotic transient
decreases in lung function due to daily exposure to smoke inhalation and suggested that
transient effects on the mechanical functions of the lungs may occur during exposure, which
may reverse spontaneously during no exposure before the next exposure (Sferlazza and
Bekett, 1991).
In a study by Mc Millan and Heath (1979), studying acute changes in lung function over 25
welders with 6 ... 25 years of experience electrician with 25 pairs taking care as compared to
be based on age and smoking habit. Pulmonary tests were conducted at the beginning and end
of shifts.
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They found significant differences in tests of lung function when compared with the
group of plumbers welders.
Akbar-Khandazeh (1993) obtained different tests of lung function before and after shift work
on the 209 welders and 109 control subjects in England. Significant decreases were identified
from morning till afternoon on the three indicators measured on both welders and the control
group, but the reduction was almost 4 times higher among welders. In general, there was no
significant association between acute changes in lung function and amount of daily exposure
to welding fumes in the result. However, acute reduction of forced expiratory volume of air
per second, was positively correlated with the product of Fe2O3. Also, welders who had not a
source of ventilation showed a maximum reduction in certain respects on lung function than
welders who work in well ventilated areas.
Kilburn and others (1990) examined the lung function of workers working shifts of 31 months
on subjects (21 welders and 10 non-welders). Changes in lung function were less than 2% and
insignificant between the two groups.
In a similar study, Donoghue and others (1994) examined the peak expiratory flow (PEF) of
welders and non smoking welders on a 12 hour work day beginning Monday. It was found
that the average PEF changed from welders, 15 minutes was significantly different from that
of non welders and media group for maximum PEF at any time during 12 hours was
significantly higher among welders. However, none of the welders had a reduction in PEF of
more than 20%, which is considered to be diagnostic for asthma.
In a more recent study, Beckett and others (1996) compared changes in lung function over 51
welders in the shipyards and 54 people in the control group, in a study over three years. Also,
these researchers examined changes in lung function observed during a work shift and
compared with changes occurring during a non-working days on a group of 49 welders. The
average activity of a welder was 4 hours in one shift and only 33% of welders used respiratory
protection. There was a significant decline at the peak of expiration found on days when
compared with the weld is not welded. The number of respiratory symptoms was low, but the
total number of symptoms increased during the days when welded, compared with those with
no solder. The authors concluded that the welding is associated with a decrease in the peak of
expiration.
In a comment made over three years, Sobaszek and others (2000) examined the acute
respiratory effects of 144 welders (stainless steel) and 223 control individuals, the beginning
and end of shifts. A significant decrease in vital force was found among welders during a
work shift, probably due to respiratory sensitization due to chromium. In addition, after 20
years of welding, stainless steel welders showed significant reduction in lung function over a
work shift compared with carbon steel welders. Moreover, decreases lung function over a
work shift were significantly related to the welding process SMEI than MIG / MAG.
Similarly, Mur and others (1985) found that welders who were protected even during the
application process SMEI have achieved significant reductions in lung function compared
with those who have used the MIG / MAG.
The issues listed above, indicate that the materials and processes used during exposure during
welding may have an influence on acute lung functions.
4.CONCLUSIONS
1. and most welding processes, the operating mode and pin technology equipment through the
passage, have a major impact on the environment and pollution is not negligible, and in case
of large-scale welded construction;
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2. and harmful health effects caused by the welding operation from physical, chemical,
electrical, mechanical and radiation accompanying the technological operation. Chemical
hazards include fumes, consisting of microparticles of aluminum, cadmium, chromium,
copper, fluoride, manganese, molybdenum, manganese, nickel, silicon, titanium, zinc etc.. and
harmful gases that arise, such as carbon dioxide, carbon monoxide, nitrogen oxide, nitrogen
dioxide, hydrogen sulfide, sulfur dioxide etc.
REFERENCES
1.Amza Gheorghe, Pîrvulescu Mihaela – Contribuţii privind evaluarea impactului
asupra mediului unei întreprinderi de fabricaţie construcţii sudate, Conferinţa TQSD,
Bucureşti, 2008.
2. Amza, Gh, Pică D., Pîrvulescu M., Apostolescu Z.- Theoretical and Experimental
Contribution on Environmental Pollution Using the Manual Arc Weldin and Electrod,
WSEAS Procedings of the International Conference Energy and Enviroment Technologies
and Equipment (EEETE 10), pg. 60+66, Bucharest, 2010.
3. Brett, S., Abson,D., Jones, D.L. – Repeair welding of plant without PWHT,
Conf.‖Integrity of High Temperature Welds‖, Nottingham, UK, Professional Engineering
Publishers, UK, 1998.
4.Gupe, S.V. - Ispection and Welding Repairs of Pressure Vessels, 2004.
5.John, H.,- Welded design theory and practice, 2005.
6.Keridge, A.E. Risk Mnagemnet, A project Manager s View Hydrocarbon Processing,1994.
7.Olsen,T.M. – Simulation of Welding for Optimized ,Aero Engine Structures,2005.
8.Sebastian,A.- Life-Cycle Assement for Ecological Prpocess, Igwt, Budapesta, 1993.
9.SR EN ISO 6520-1. Sudură şi procedee conexe. Imperfecţiuni în îmbinări sudate prin
topire la metale.
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IMPACT ON CONTRIBUTIONS FUMES FROM WELDING
PROCEDURES WELDER HEALTH OPERATORS
Dr.ing. Gheorghe AMZA, Dr.ing. Zoia APOSTOLESCU,
Drd.ing. Liana Sanda PAISE, Drd.ing. Maria Dragomir GROZA
Polytechnic University of Bucharest, [email protected]
Abstract: This paper presents a series of investigations undertaken to establish the impact of gas welding results
in fusion welding procedures and welders health operators who work in departments making welded
construction. Are the main gases that occur in fusion welding and main effects of short-term and long on the
human body.
Keywords: gases, welding, health impact.
1.INTRODUCTION
According to the literature, arc welding process generates a variety of toxic gases, of which
part and tropospheric ozone, nitrogen oxides, carbon monoxide and carbon dioxide.
Also, due to degreasing chemicals used to provide basic cleaning surfaces prior to welding
materials (Howden and others, 1988) such as chlorides, hydrocarbons, give rise to gas
combustion, which, according to the literature in this area may pose health hazard to operators
welders. One of the agents commonly used is trichlorethylene that has a high vapor pressure.
Airborne vapor around the arc and are subject to oxidation due to ultraviolet radiation, which
produces a gas that irritates the lungs, called phosgene.
Gases produced during welding operation can come from various sources and depend greatly
on the type of welding process, as follows.
- Protective gas;
- Electrode coatings and materials from their rods;
- The reactions taking place in the spring with atmospheric constituents;
- The reaction with atmospheric gases ultraviolet light;
- Degreasing agents of decomposition and organic coatings of metal to be welded (Villaume
and others, 1979).
2. GAS MAIN RESULTS DURING BE WELDED
2.1.Ozonul tropospheric
Ozone is an allotropic oxygen. Occurs during welding of atmospheric oxygen in a
photochemical reaction with ultraviolet radiation of the arc. The reaction takes place in two
phases to the radiation waves less than 210 nm (Edwards, 1975).
Under the effect of ultraviolet radiation arc, atmospheric oxygen in combination with CO,
participate in training an excess of ozone O3 in the troposphere, where reactions.:
O2 + hυ (<210 nm) = 2O
(1)
O + O2 = O3
(2)
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where: h - is Planch's constant ( h  6,626  103 J / s ); υ - frequency ultraviolet radiation.
The rate of ozone formation depends on the waves and the intensity of ultraviolet light
generated in the arc welding material, type of electrode used, protective gas, welding
procedure, welding regime parameters such as voltage, intensity and arc length. As effect
on operators, tropospheric ozone is a severe respiratory irritant.
2.2.Oxizii nitrogen
Nitrogen oxides are formed during welding high temperature oxidation of atmospheric
nitrogen produced by arc or flame (Villaume and others, 1979). The first reaction that
occurs in the formation of nitrogen oxides of nitrogen and oxygen atmosphere existing in
the
coating
is:
N2 + O2 = 2NO
(3)
The rate of formation of nitric oxide in the temperature of 12000C is insignificant, but
increases with increasing temperature. After dilution with air, nitrous oxide can react
further with oxygen to form nitrogen dioxide, after the relationship:
2NO + O2 = 2NO2
(4)
Under the effect of the arc radiation, nitrogen dioxide (NO2) in the presence of organic
compounds and carbon oxide, participates in the formation of excess ozone in the
atmosphere by reactions:
NO2 + hυ = NO+O
O + O2 = O3
(5)
(6)
When nitrous oxide inhalation, and resulting effects are irritation of eyes, nose and lungs.
Exposure to high concentrations can cause severe lung irritation and edema. Chronic
exposure may affect lung officials mechanism. It is known that nitrogen dioxide levels in
the welding can be up to 7 ppm during welding with cored wire. Levels inside the face
mask, however, was 2 ppm, thus showing that the welder is protected by masking the
effects of the gas resulting from welding.
Values set by WHO maximum concentration of NO2 in air are: 400μg/m3, for an
exposure duration of one hour and 150μg/m3, for a period of 8 hours exposure.
2.3.Dioxidul carbon and carbon monoxide
Carbon dioxide CO2 and carbon monoxide CO is formed from the decomposition of
organic compounds in electrode coating and the inorganic carbide coatings. Carbon
monoxide is often encountered when welding steel electrode coating containing calcium
carbonate CaCO3 or the welding in protective environments protective gas when the gas is
carbon dioxide or a mixture of argon and carbon dioxide at high temperatures in spring
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and molten metal surface, carbon dioxide is reduced to more stable carbon monoxide.
Carbon monoxide toxicity is caused by formation of carboxyhemoglobin in the blood,
which hinders the ability of blood to carry oxygen to various tissues of the body.
According to researcher Smith (1991), if carboxyhemoglobin level reaches 50%, un
consciousness can occur. Evidence indicates that carbon monoxide levels are low, the
measurements are far from arc welding, however, higher concentrations were found in the
arc welding of carbon dioxide when used as protective gas. Others believe that carbon
monoxide levels can be high both in areas with poor ventilation and in one with good
ventilation. Tsuchihana and others (1988) shows that the concentration of carbon
monoxide near the welded seam were eight times higher when welding in confined spaces
than in the outdoors. Found also individual levels, the sweat that operating in closed
spaces, of carboxyhemoglobin exceeding the 15%, it varies at around 20%, values that
increase vascular permeability to macromolecules and vessels leading to pathogenesis and
their atherosclerosis.
According to Smith (1991), only values above 30% can lead to changes in the
electrocardiogram, headache, weakness, dizziness and unconsciousness.
3.EFECTELE GAS WELDING OPERATORS AND HUMAN ENVIRONMENT
Health effects can be:
- Acute: effects arising from short-term inhalation of different gases and fumes arising
from welding process can be caused by certain processes and duration of exposure;
- Chronic: long-term effects are not taken very much into account, at present, because it
confuses the effects arising from other factors such as smoking.
3.1. Short-term effects
The main effects of short-term, therefore, researchers have analyzed these effects and
found the following are:
- Metal fume fever. Metal fume fever occurs in welders inhaling smoke that occurs in
welding and containing zinc oxide, while there are other components that can produce the
same symptoms such as copper, aluminum and magnesium. Symptoms of metal fume
fever resemble the flu usually occur several hours after exposure and include a metallic or
sweet taste, chills, thirst, fever, muscle aches, fatigue, pain, gastro - intestinal, headache,
dizziness and vomiting. Symptoms disappear after one to three days after exposure
without
residual
effects;
- Exposure to tropospheric ozone. Tropospheric ozone exposure generated by the welding
arc and plasma arc welding may produce excessive mucus secretion, headache, lethargy,
eye irritation, respiratory irritation and inflammation. In extreme cases, excess fluid may
occur and hemorrhaging in the lungs;
- Exposure to nitrogen oxides. Exposure to nitrogen oxides similar effect with ozone
exposure. Inhalation of nitric oxide does not always produce immediate irritant effect but
can lead to excessive fluid in the lung tissue which disappears within hours after exposure.
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3.2. Long-term effects
But more important are long-term effects, therefore, most researchers have focused their
attention.
Details of exposure to fumes and gases lasting results from specific welding processes are
presented below:
- Respiratory system: based on studies that were performed demonstrated that chronic effects
are worsened by smoking;
- Nervous system: all components of fumes arising from welding, micro lead and manganese
have negative effects on the nervous system.
- Cardiovascular system: the carbon monoxide gas welding protective environments reduce
the ability of blood to carry oxygen and therefore, exposure to carbon monoxide is extremely
dangerous especially for welders who have heart problems;
- Skin: chromium compounds, which may be present in stainless steel or fumes resulting from
the welding process of this material are a common cause for dermatitis;
- Carcinogenic effects: There is concern regarding the presence of agents that cause cancer in
some smoke and fumes from the welding process. In analyzing this literature can be said that:
- Nickel and chromium can cause cancer of the respiratory system;
- Tropospheric ozone is a suspect in lung cancer but no studies to prove this;
- Arc emits ultraviolet radiation emitted by certain wavelengths that have the ability to
produce tumors in animals and in individuals who overexpose, but there is confirmation of the
effect of the welders.
Lung cancer is the most common cancer found in humans. Studies of lung cancer among
welders indicate an increased risk with 30 ... 40% compared with the general population.
Because smoking and exposure to other carcinogens such as asbestos fibers may have
influenced the results, it is not known exactly when the welding operation is a danger in terms
of lung cancer. It is considered that welding low alloy steels is of no great health. Stainless
steel welders exposed to chromium and nickel are considered a high risk group;
- Asthma: Asthma is caused by inhalation of professional pathogens at work and therefore lay
apart from asthma and the symptoms of it, observed a slight improvement when it is away
from work (Palmer and Eaton , 2001). When welding stainless steel, large amounts of
chromium and nickel in smoke are considered responsible for respiratory sensitivity. A
possible association between welding and occupational asthma remains unclear. Many of the
studies are difficult to compare because of differences in the working population, industrial
facilities, welding techniques and duration of exposure. In a 1024 study by welders workers
found that the rate of occurrence of asthma is 7 times higher than the male population
working in other professions. When welders younger men (ages 20-44 years) were separated
for analysis, the rate was nine times higher than the general male population working in other
professions;
- Bronchitis: bronchitis is a disease characterized by airway inflammation due to substances
such as tobacco smoke, nitrogen dioxide and sulfur dioxide. In supervision welders significant
increase was observed symptoms of acute bronchitis, which is the most common disease of
the airways. One factor affecting the detection of chronic bronchitis in welders is tobacco
smoke and chronic bronchitis caused by tobacco smoke in the general population.
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- Pneumoconiosis and fibrosis: examination of welders lungs were observed amounts of iron
oxide deposited without fibrosis present. This condition is known as siderosis and is usually
classified as benign. Examinations were made on lung tissue from 10 welders with exposure
to welding fumes resulted in 8 to 40 years and have symptoms of cough and dyspnea and may
describe.
A case by a welder with interstitial lung fibrosis caused by iron oxide deposited in the lungs.
He worked as a welder for 27 years most of the time in places inadequately ventilated. After
eight years as a welder he made tuberculosis which was treated successfully. After 10 years
you have made siderosis without respiratory symptoms. After 27 years was diagnosed with
respiratory failure. Respiratory problems were due to exposure to large amounts of fumes
from welding operations in enclosed spaces. Any contributed tuberculosis infection as a
harmful factor;
- Respiratory infections and immunities: respiratory infections have been shown to be
severely elevated, on a long and very common for a short period among welders. Pneumonia
caused by exposure to fumes resulting from welding and cutting operations should be treated
in hospital. The authors indicate that inhalation of welding fumes can worsen the condition
resulting from pneumonia. Several studies have reported an excess mortality due to
pneumonia in welders.
- Lung Cancer: Potential association between lung cancer and welding production continues
to be considered excessive. Several studies have shown an increased risk workers the
incidence of lung cancer among welders. In 1990, the International Association for Research
on Cancer (IARC) concluded that any gas in welding is a carcinogen in humans.
Interpretation of the risk of lung cancer is more difficult when there are uncertainties in most
studies.
- Skin and hypertensive effects: skin can absorb ultraviolet radiation from arc welding
emergent fusion. Production of molten metal and ultraviolet radiation are common in these
assembly operations. Disease severity caused by radiation depends heavily protections offered
such as clothing, welding process, exposure time, radiation intensity, distance from which
radiation occurs. Skin sensitivity to irritants generated during welding due to compounds
derived from chromium, nickel, zinc, cobalt, cadmium, tungsten. Chromium in welding gases
were shown to be producing allergies in people sensitive to chrome.
- Effects of CNS constituents resulting gas welding aluminum and magnesium have been
suspected as causative of neuropsychiatric symptoms in workers exposed to specific
occupations.
In one case, Gunnarsson and others (1992) found the risk of neural motor system disease that
is fatal and progressive.
Affect the central nervous system effects due to magnesium and aluminum welders were
examined by Sjogren and others (1996). A large majority of psychological and neurological
tests were made on groups of welders with long exposure to metals. Aluminum welders (n =
38) had urinary concentration of 7 times and have reported many more changes neurological
and motor system decreases than others (n = 39). Welders exposed to manganese (n = 12) had
lower results at 5 locomotor tests. However, welders had a very high level of magnesium in
the blood to other control groups. The authors noted subtle differences in locomotor
functioning, which were observed in aluminum welders aluminum concentration in urine of
50 mg / l and recommended that measures be taken to reduce the concentration of aluminum
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welders. They also concluded that despite the low concentration of blood and lower duration
of exposure, magnesium was the cause of the locomotor symptoms of welders. They
recommended that the working environment for welders using magnesium electrodes allies to
be improved;
- Effects Reproductive studies conducted have shown that welding can affect fertility.
4.CONCLUSIONS
1. The main sources of pollution of environmental pollution due to the technological process
of welding are: lightning, electromagnetic radiation, dust and micro powders fumes, gases
(COx, SOx, NOx, H2, H2S, CH4, COVs, etc.), Fog, pollution photochemical formation of
tropospheric ozone, powders, suspensions, heavy metals and minerals break down soluble
substances, waste and industrial waste;
2. Is estimated that over 2.2 million work full time welders worldwide, most feeling some
adverse effects on their health due to their occupation;
3. Harmful health effects caused by the welding operation from physical, chemical, electrical,
mechanical and radiation accompanying the technological operation;
REFERENCES
1.Amza,Gh., Pîrvulescu, M. – Contribuţii privind impactul asupra mediului a procesului de
sudare manuală cu electrod învelit, Lucrările conferinţei ASR SUDURA, Constanţa, 2008.
2.Amza, Gh. – Ecotehnologie, Editura Printech, Bucureşti, 2007.
3. Brett, S., Abson,D., Jones, D.L. – Repeair welding of plant without PWHT,
Conf.‖Integrity of High Temperature Welds‖, Nottingham, UK, Professional Engineering
Publishers, UK, 1998.
4.Gupe, S.V. - Ispection and Welding Repairs of Pressure Vessels, 2004.
5.Heiple,C.R.-Roper, J.R.- Mechanism for minor element effect on GTA fusion zone
geometry, Weld, J., vol.61, 1982, pg.97-102.
6.John, H.,- Welded design theory and practice, 2005.
7.Keridge, A.E. Risk Mnagemnet, A project Manager s View Hydrocarbon Processing,1994.
8.Olsen,T.M. – Simulation of Welding for Optimized ,Aero Engine Structures,2005.
9.Sebastian,A.- Life-Cycle Assement for Ecological Prpocess, Igwt, Budapesta, 1993.
10.SR EN ISO 6520-1. Sudură şi procedee conexe. Imperfecţiuni în îmbinări sudate prin
topire la metale.
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FEATURES FOR TRANSPORT AND AIR MECHANICAL SYSTEMS
OF DANGEROUS GOODS
Dipl.ing.drd. Eugen Dumitru BUSA, Director-CFP IFPTR ARAD
Abstract: Transport of dangerous goods are regulated activities, they take place under the direction and control
of the authorities and specialized bodies in an institutional framework determined by national and international
law. Of economic, transport infrastructure is the crucial element without which both production and trade would
become meaningless, it is an essential element of a civilization, is also a necessary accessory of other economic
activities.
Keywords: transport, airport, infrastructure;
1.CURRENT STAGE MODE OF TRANSPORT AND AIR MECHANICAL SYSTEMS
OF DANGEROUS GOODS
Development, diversification and modernization of transport of dangerous goods have
been caused by expansion and intensification of production and circulation of goods,
increasing international division of labor and not least the need for their specialization.
Transport of dangerous goods are regulated activities, they take place under the
direction and control of the authorities and specialized bodies in an institutional framework
determined by national and international law. Of economic, transport infrastructure is the
crucial element without which both production and trade would become meaningless, it is an
essential element of a civilization, is also a necessary accessory of other economic activities.
In the context of EU membership of Romania, the existence of a developed, connected
to the European transport network, would allow significant development of economic
competitiveness, and thus creating prerequisites rapid integration of the Romanian economy
in the European market. We remember, so low road sector development until the year 1990,
but with a sharp increase in recent years, development done, unfortunately, due to favorable
reduction or similar rates of other modes of transport.
All these developments can be clearly evidenced by the situation of transport
infrastructure, the current infrastructure was an evolution of development and modernization
of the economy like the Romanian one of the main obstacles being reduced resources of
financing transport infrastructure in Romania coming a number of key issues that define the
most important changes that have occurred in the transport sector since 1990 till present.
These include fundamental changes in the structure of transport sector in Romania, from a
planned economy (economy) to a transportation-based economy driven by market demand,
the decline of the industries most likely use of rail transport and regional instability in the
neighboring Balkan countries , inheritance of inadequate investment in infrastructure
maintenance, road and rail damage however led to a significant reduction in the number of
tonne-kilometers of freight carried by rail, a change in the pattern of traffic flow and underutilization of waterways, especially in the international transport of bulk cargo and container
traffic.
Increased environmental degradation, so the effects of transport activity, but also by
degradation of natural habitats by supplying network infrastructure, economically unjustified,
in addition, there was a relatively slow uptake of innovative ideas and technology, which has
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reduced opportunities to take advantage of alternative funding sources, and new modes of
transport such as multimodal and combinat.
Toate these issues have led to 'unjust' development of the transport market in Romania,
especially in terms of its competitive potential.
The current situation of the national transport system, characterized by a reduced
number of highways and connections to the motorway or fast roads, the bypasses of large
urban agglomerations, the freight vehicle parking and special parking needed to transport
dangerous goods, the existence of naval facilities in an advanced state of decay and a railway
network in the most part, have old and outdated rolling stock is, however, required major
investments in a relatively short time in transport infrastructure, which must reach a level of
development, enabling mobility needs in the best conditions so that, to ensure capacity,
quality and safety required by European standards.
It is imperative that requires a balanced development of all modes of transport, road,
rail, sea and air as well as quality services mainly to transport of dangerous goods.
The amount of freight transported is very important because it shows the intensity of
economic activity, economist and businessman Warren Buffett even said to him, the evolution
of the quantity of goods transported by rail is the best economic indicator.
Transport of dangerous goods is a specialization of transport of goods is an important
part of material production and their function decisively influences the movement of goods
and other branches of world economy, including international trade. Being effective means
for marketing material inter-state economic relations, international economic transport can be
considered as circulatory system of the entire world economy.
The advantages of monitoring the handling, storage and transport of dangerous goods
lies and avoid accidents / incidents such as:
 Fireworks accident in Enschede, the Netherlands, in May 2000 highlighted the major
danger posed by the activities of storage and manufacture of pyrotechnic and
explosive substances.
 The explosion at a fertilizer plant in Toulouse in September 2001 has raised awareness
of the accident potential arising from the storage of ammonium nitrate fertilizer or
ammonium nitrate, in particular of material rejected manufacturing process or returned
to the manufacturer materials "off-specs" (conformity with the specifications).
 Frequent Accidents that occur during transport of dangerous goods due to improper
stowage of cargo, accidental spills, etc..
Examples of sins can continue, but these things need increasingly shows the
importance of monitoring the handling, storage and transport of dangerous goods and
developing policies to prevent accidents, major incidents and a coherent and comprehensive
framework
in
EU
countries
States
these
international
agreements.
Currently in Romania dangerous goods legislation does not fully meet the needs of the Union
are multiple European.Causes from simple ignorance and lack of political will by passing
through the crisis of innovation in this area can reach even a financial crisis reflect on this
area. Also lack of specialists in this relatively new field has a negative impact.
Carriage by air of dangerous goods
The technical and economic features of air transport of dangerous goods include:
 speed - is the essential characteristic of air transport. This is evidenced by the speed of
movement of aircraft that can not be matched by no other means of transport;
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 regularity - is that air transportation is performed by a definite program at any time of
year, both day and night;
 opportunity - is the fact that this mode of transport available to interested parties,
whenever and wherever they are arranged endpoints, the most modern means of
transport.
Airport development programs provide a platform for achieving intermodal
transport (air, rail, road). Contribution of air transport of dangerous goods transport is
marked by shortcomings such as:
 Airport services are still underdeveloped;
 lack specific features leading to landing in special circumstances;
 monitoring services and aircraft maintenance is not up to international standards;
 investment
for
dangerous
goods
cargo
terminals
is
insufficient;
Development, modernization and efficiency of air transport of dangerous goods is
possible by completing and harmonizing legislation in EU countries, improving
security and increasing the level of training of staff is involved in transport.
Proposals for the aircraft carrying dangerous goods and how to transport dangerous
goods are:
 To increase safety on the transport of certain dangerous substances aircraft carrying
dangerous goods must be equipped with advanced safety systems and certified to carry
certain categories of dangerous substances to the danger presented by these
 Providing aircraft carrying dangerous goods with very advanced safety systems to
reduce the risk of incidents / accidents while increasing safety for them.
Dangerous goods transport networks
The technical state of Romanian infrastructure not fully complies with European
standards, but need to mention a fact of utmost importance: Romania has a network of
infrastructure (roads, railways, and waterways, sea and river ports, airports, airways) which
ensures the connection of all localities to the national transport and international transport
systems. Geographically and network infrastructure, Romania fulfills the role of undisputed
hub of continental and intercontinental transport on main routes and geographical North West
South
East.
Air Network : consists of the Romanian airspace where air routes are defined according to
traffic flows in Europe coordinated by EUROCONTROL. Romanian airspace, airways that
are used both for overflight by ensuring service control and air traffic control and for taking
off and landing at Romanian airports, which are so connected with airports around the world.
The airports in Romania consists of 17 airports, of which 4 are open to domestic and
international passenger traffic and cargo and 13 are specific to particular local interest.
2.CONCLUSIONS AND ORIGINAL CONTRIBUTIONS
Worldwide, European and national efforts are made to prevent any major accidents resulting
in property damage, casualties or environmental pollution, because the human factor plays a
decisive
role
in
the
development
of
transport
operations.
In
terms
of
mechanical
systems
for
air
transport:
One of the most pressing contemporary problems of carriers is due to transport of
dangerous goods issues raised especially in terms of safety for them. Interventions of the UN
specialized agencies, and Member of the EU have shown the consistency and common mark
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by developing content standards regulations specific to the transport of dangerous goods is
reflected
in
national
regulations
in
the
field.
Mode of transport by air of dangerous goods must be chosen according to the risk that it
involves their transport, the type of hazard of hazardous substance. The main objective risk
assessment of goods / hazardous substances is to provide a reliable database to decide safety /
security
measures
(risk
management)
according
to
specific
uses.
Risk assessment provides an estimate of the situation that if a substance used as
defined by an exposure scenario could cause adverse effects. This includes a description of
the effects and to calculate the probability that they occur, and an appreciation of their
extension or size.
Currently closed body vehicles carrying dangerous goods have safety systems to avoid
accumulation of gas in case of accidents or incidents and given that vehicles transporting
dangerous goods type box (sealed) the transport of liquids dangerous ( gasoline and so on)
can in accidental situations such as incident / accident, capsizing due to climatic factors-wind,
bad stowage, etc. skidding. are able to discharge the load compartment leading to the
formation of vapor and liquid in a mixing proportion of oxygen increases the likelihood of
fire or may flow on roadways increased risk of road accidents and accidentally pollutes the
environment.
Proposals for the aircraft carrying dangerous goods and how to transport dangerous goods are:
 To increase safety on the transport of certain dangerous substances, all aircraft
carrying dangerous goods must be equipped with advanced safety systems and
certified to carry certain categories of dangerous substances to the danger presented by
them and to reduce the risk of incidents / accidents while increasing safety for them.
 aircraft carrying dangerous goods must be equipped with all types of intelligent
transport systems to be responsive to all situations that appear to limit reduces the
number of accidents, casualties and avoid accidental environmental pollution.
 Type of aircraft used to transport dangerous goods must be chosen according to the
risk that it involves transportation. The main objective of the goods and hazardous
substances risk assessment is to provide a database for groups of substances to decide
safety / security measures (risk management) .
Shares transport of dangerous substances according to the state of aggregation,
risk factors presented by these classes of risk and appropriate identification of each
type of vehicle transport.
Completion
of
legislation
on
dangerous
goods
following:
-a law must not be dense but clear and to the point answer to the problems faced by the
shipper,
carrier
and
consignee
of
dangerous
goods.
-a policy point of view Romania has to continue the compatibility of national legislation with
the acquis communitaire which includes laws and international agreements to which Romania
is part and must participate actively in the development of law by creating and sending
experts to the Commission Economic Commission for Europe (ECE) from the United
Nations.
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REFERENCES
1. Romanian Road Authority, Cuciureanu, M. - guide emergency measures I & A
Publishing House, Bucharest, 2005;
2. Busa, E. - Transportation of Dangerous Goods, the Third Edition, International
Multimedia Publishing House, Bucharest, 2012;
3. Busa, E., Legislative Guide of dangerous goods, Ed.a III International Multimedia
Publishing, Bucharest, 2012;
4. Directive 2008/68/EC of the European Parliament and Council directive on inland
transport by road, rail or inland waterway transport of dangerous goods, 2008;
5. Romanian Government - Ministry of Transport, sustainable transport strategy for
2007-2013 and 2020, 2030, 2008; an elaboration of recommendations (ferenda law)
legislation on storage, transport, continuous training of personnel involved in this
field.
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STUDIES REGARDING THE MANUFACTURE OF RED GLASSES
USED IN VEHICLE CONSTRUCTION INDUSTRY
Associate Professor PhD.Eng CĂPĂŢÎNĂ Camelia, PhD, ―Constantin Brâncuşi‖
University, Faculty of Engineering, Târgu-Jiu, Geneva 3, 210152, Gorj, Romania,
[email protected]
Professor PhD.GĂMĂNECI Gheorghe, ―Constantin Brâncuşi‖ University, Faculty
of Engineering, Târgu-Jiu, Geneva 3, 210152, Gorj, Romania, [email protected]
Abstract: Recently, glass industry in Romania has been affected by the tendency to avoid polluting
substances. A similar problem is outlined related to the cadmium glasses used for signalizations in the car
construction industry.
The paper presents the advantages of obtaining red glasses based on copper that is introduced as an
alloy of Cu – Sn. The red copper glass may substitute cadmium glasses and they are used for signalizations in
the car construction industry.
Keywords: glass, alloy, signalization, melting
Introduction
Glass is a mixture of silicon dioxide and silicates of different metals. They are
amorphous materials with high mechanical resistance and roughness, with a small dilating
coefficient. At high temperatures, the glasses react like under-cooled liquids with big
viscosity. Glasses have no defined melting point, and by heating they soften gradually,
allowing the glass processing by blowing, pressing, pouring, laminating.
Glass is obtained by the melting in special ovens and the physical properties are
determined by their composition [1].
The colorants used in glass industry are classified in three categories [2]: ionic
colorants, molecular colorants, colloidal colorants. The ionic colorants are generally metallic
oxides: copper oxides, chrome oxides, manganese oxides etc. The molecular colorants are
represented by selenium that gives a pink colour, by sulphur that gives a yellow colour, and
the mixture of CdS + CdSe that gives a red colour whose shade depends on the report
between the two components. The colloidal colorants are the metals that, by thermal
treatments, are dispersed as a colloidal solution engraving colours to the glass, depending on
the sizes of the colloidal particles.
The consumers of coloured glass are the air, naval and terrestrial transports. The light
signalizations in transports are extremely important and the used colours are red, green, blue
and yellow.
In the recent years, the glass industry has been affected by the tendency of avoiding
the use of polluting or dangerous substances that manifest in the entire world, but especially
on the market of the developed countries that are interesting for the glass producers in
Romania. A similar problem is outlined related to the cadmium glasses that are also toxic for
the human body and polluting for the environment. Cadmium glass is used in vehicle
construction industry, for signalizations of the cars.
The paper presents the advantages of replacing the cadmium glass with copper glass.
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Experimental
Table no. 1 presents the oxide composition of the examined glass.
The alloy of Cu – Sn has the copper weight of 65%:
Table no. 1. Oxide composition of examined glass
Component
SiO2
B2O3
Al2O3
Na2O
K2O
CaO
MgO
CoO
Fe2O3
Cu
Sn
Red glass% gr
71,97
1,11
0,5
9,86
4,98
10,24
0,01
0,8
0,53
White glass % gr
72,18
0,29
0,32
15,02
3
8,28
0,9
0,01
-
Blue glass % gr
61,86
2,84
0,22
11,36
4,8
3,55
0,1
15,87
0,02
-
Melting was accomplished in an electric oven with baguettes of silicon carbon, with
an automatic regulation in refractory ceramic crucibles at 14500C in normal atmosphere, for
200 minutes.
In these conditions, we obtained melting having a satisfying quality and colourless
glass samples after cooling.
For developing colours, the samples have been thermally treated at 5800C, for 85
minutes.
For all the three glass samples: red, white and blue, we determined the density as the
first method of hydrostatic weight by using an electronic analytic balance. The glass samples
were washed with distilled water and alcohol, and they were finally dried. The glass samples
were weighted in the air, obtaining the mass m0 and in distilled water, obtaining the mass ma‘.
The glass density (dst) is calculated by the relation[1]:
m0
d st 
 d a (g/cm3) (1)
m0  m a
where: ma = ma‘ - mf; mf is the weight of the wire suspending the sample and da – the density
of the distilled water of the work temperature, namely 0,99723 g/cm3 at 24 oC.
Thermal dilation determines the glass reaction in case of soldering or overlapping on
other types of glass. It is featured by the coefficient of linear thermal dilation that was
experimentally determined by means of the Weiss differential dilatometer modernized by
adding an electromagnetic micrometer and a register X-Y. The glass sample was heated with
the constant speed of 3 oC/min.[5]
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Results and discussions
Even if the use of the alloy of Cu-Sn may offer, at industrial level, the advantage of
capitalizing the bronze wastes resulted when processing the metals by chipping and
perforating [1, 2].
In the alloy composition, the copper weight may vary between 60 and 70 % and of the
corresponding tin. The melting is made in a refractory crucibles where we first introduce the
copper and then, after the copper melting, we add the tin that dissolves in the melting. The
alloy is poured as bars from where, by mechanical processing, we obtain a quire fine powder.
For avoiding the fast melting of the alloy introduced in glass and its deposit on the
bottom of the crucibles where the melting occurs, we recommend to mix the powder with a
solution of sodium silicate. Both in the mixture of raw materials and in the melted glass, it is
avoided thus the separation of the metal and its sedimentation. However, we need to
homogenise the melted glass in order to provide the manufacture of a ruby glass with a
uniform colour with no different shades.
For understanding the reaction of the alloy during the processing of the mixture of raw
materials and of glass, beside the ideas presented in the previous pages, it is useful to examine
the phase accessible diagrams of thermal balance. Thus, figure 1 presents the diagram of the
binary system CuO-SnO2 [3, 4] corresponding to the oxygen concentration in the normal
atmosphere. We may find that the tin is in the maximum oxidation state, a fact the emphasizes
the stronger tendency of oxidation, of capturing the oxygen of the environment, rather than
the copper.
Fig.1. Diagram of phase thermal balance of the system CuO – SnO2 in the normal atmosphere
This fact is especially emphasized in the diagram of figure 1 where, at a very reduced
oxygen pressure, the copper is stable as Cu+ while the tin is maintained at Sn4+. It is obvious
that the tin ―protects‖ the copper against the oxidation when they are together, and the oxygen
in that environment is in the red. In the conditions of the presence of a sufficient oxygen
quantity, the copper starts to oxidize only after the tin got to saturation as Sn4+.
As it was shown, there is also the opinion according to which some parameters of the
technological process are capitally important for the quality of the manufactured red glass.
For this reason, this study tried to follow some of the important parameters without
considering that this very complex subject was exhausted especially in the industrial practice.
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The obtained results for density are presented in table no. 2.
Table no. 2 Results of density determinations
Glass
Red glass
White glass
Blue glass
Densities
Experimentally
determined
2,4965
2,5076
2,64414
Table 2 shows a value of the red glass density that is close to the ménage white glass
density, which is advantageous for producing overlapped glass objects. The values of the
experimentally and theoretically determined densities for the glass manufactured in the
laboratory are close, within the limits of about 1 %. For the ones taken over from industry,
samples and compositions, the differences are bigger, over 2 %, especially in case of the blue
glass containing CoO.
Density is interesting for the industrial practice because it allows the fast spotlighting
of the potential changes of glass composition.
The values of the coefficients of thermal dilation experimentally determined for the
three glass samples are presented in table 3.
Table 3. Values of the coefficients of thermal dilation
Glass
Ruby copper glass
White glass
Blue glass
st experimental,
(10-7.K-1)
91,87
99
99,36
The concordance between the experimentally determined values and the calculated
ones is satisfying, except for the blue glass where the difference seems too big. Practically,
the dilation coefficient of red glass is quite close to the values found for the other glasses for
making possible their welding or overlapping.
Conclusions
The red colour is obtained due to the use of the alloy of Cu – Sn, as a copper source,
but also as a tin one, known as a reducing component.
The glass composition is established depending on the uses and the properties of other
types of glass it will be in contact, and the alloy of Cu – Sn constitutes the most reasonable
solution.
The main properties of the red glass used for signalizations in the car construction
industry are comparable and compatible with the ones of the industrial glass currently used
for ménage products.
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References
[1] Baltă P., Glass Technology, Didactic and Pedagogic Press, Bucharest, 1984
[2] Weyl W.A., Coloured glass, Society of Glass Technology, Sheffield, 1967
[3] Cristea V., Becherescu D., Simonfi P., Construction Materials Magazine,
Bucharest, Vol. V, no. 2, 1975, p. 87-88
[4] Santander N.H., Kubaschewski O., The thermodynamics of the Copper – oxygen
system, High Temp – High Press, 7, 1975, England, p. 385-391
[5]Baltă P., Dumitrescu O., Spurcaciu C., Guide of Practical Works at Glass
Technology, Bucharest, 1985
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GLASS PLATES FOR MOTOR VEHICLES AND OTHER MEANS OF
TRANSPORT
Associate Professor PhD.Eng. Camelia CĂPĂŢÎNĂ, „Constantin Brâncuşi‖ University,
Faculty of Engineering, Geneva Street, No.3, Târgu-Jiu, [email protected]
Professor PhD. Gheorghe GĂMĂNECI, „Constantin Brâncuşi‖ University, Faculty of
Engineering, Geneva Street, No.3, Târgu-Jiu,
Abstract: At present, the majority of high quality glass plate is used in vehicle industry. The paper
presents the technological process for obtaining glass plate, used in vehicle industry. Besides the usual
attributes of high quality plane glass, those used in vehicle industry must not result in sharp and cutting splinters
when broken, being dangerous for the passengers. This quality, due to which it is called safety glass, is obtained
by various methods.
Keywords: glass, vehicles, furnace, triplex
Glass plate for vehicles and other means of transport
Window panes or plane glass are glass objects modelled under the form of plates whose
thickness is relatively low compared to their length and width.
Window panes industrially produced are classified into six basic categories:
1. Sheet glass panes are transparent glass plate pieces, relatively thin, with smooth
surfaces, apparently flat – parallels, with gloss specific to glass flame modelling, with its
characteristic surface curls, visible under an acute angle or in reflected light.
2. Polished glass panes are transparent plates of glass, with plane – parallel surfaces,
which do not distort the objects reflected through transparency under different angles.
Smoothness and parallelism of the surfaces are reached through polishing and mechanic
polishing.
3. Ornament glass panes are plane glass plates whose transparency is more or less
reduced by imprinting decorative drawings on one of the plate‘s surface.
4. Reinforced glass panes are plane glass plates which have armour net in the middle.
These panes can be obtained with polished or ornamental surfaces.
5. Special glass panes are different varieties of coloured plane glass plates, transparent or
translucent, clear or opalescent.
6. Machined glass panes, comprise glass sheets which are polished, ornament, reinforced
or special, which where supplementary machined in order to obtain new attributes, necessary
for different uses.
The methods of obtaining glass panes differentiate not only by the equipment of the
machining room, but especially by the way in which the strap is led. In the specialized
literature there are known methods implying strap vertical circulation: Fourcault and Pittsburg
methods and with horizontal circulation: Coluburn – Libbey – Owens method.
The Fourcault method implies the glass pane being drawn trough a ceramic body,
directly under the form of continuous strap from the melt of a continuously operated furnace.
The surfaces of the glass panes have a specific gloss because of the so-called ―fire polishing‖
and due to the lack of imprints.
The paper presents technologies of obtaining the glass plates for vehicles and other
means of transport.
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Table 1.1. presents the composition of glass pane
Table 1.1. Composition of glass pane
Oxides
% gram
SiO2
73
Na2O
14.5
CaO
7.4
MgO
3.2
Al2O3
1.8
Fe2O3
0.1
Production of triplex glass plates
In manufacturing triplex glass plates there can be used glass plates obtained by vertical
drawing, selected especially from the current production, with a very low number of defects
and with very smooth surfaces. Preferably there are used float plates. As an intermediary
elastic material, only celluloid had been used for a long time. However, celluloid triplex
grows yellow in time, and the adherence of the plates on it diminishes; at present celluloid is
replaced by Polyvynil Butyral. Films of Polyvynil Butyral also called butafol, are 0.5 mm
thick and come in rolls. The technological process comprises the following stages:
- washing and drying the glass plates and the butafol;
- cutting the necessary dimensions with the help of patterns;
- setting up the packages;
- preliminary pressing the packages in the crushing mill, with the help of a conveyor
with 5 sections, where the temperature rises with 10 °C each (from 60 la 100 °C), or with the
help of vacuum created by some rubber frames where the package is placed. Thus the air
bubbles between the plates are eliminated;
- visual control of quality;
- pressing the packages in the steamer, at 98 - 105°C, and 18 - 20 at, for an hour;
- adjusting contours, bevelling edges and angles;
- final control of triplex. Butafol is thawed at temperatures higher than 15°C and thus it
adheres better to silica glass (adhesion force is 70—80 daN/cm2).
Triplex plates must have over 84% transparency, must stand temperatures between 60°C and + 60°C and thermal shock (especially plates provided with electrical heating), must
stand unilateral pressure (of the 1 - 3 daN/cm2 kind), and if broken it must not shatter in too
many pieces. A broken triplex plate has radial and concentric cracks around the area where
the mechanic shock occurred.
These plates are used for vehicles, railway coaches, planes, ships, protection glasses,
under pressure machines (low temperatures) etc. They can also be curved, as well as with
electric heating systems with internal resistance or semiconductor films, incrusted on the glass
surface. Triplex is also made of hardened glass plates. Triplex is the most expensive type of
plane glass and that is why it is replaced, where possible, by hardened glass plates.
Production of hardened glass
Manufacturing the hardened glass, which due to its properties is also called securite,
consists mainly of heating the plate to a temperature close to the thawing temperature,
followed by its rapid cooling with intense airstreams. Cutting the plate to the necessary
dimensions, edge bevelling and any other mechanical conditioning must be done before
hardening, because of the afore mentioned property.
Hardening is made in two types of installations which are differentiated by the way in
which the plate is maintained: horizontal or vertical.
Horizontal installation has a continuous activity which can be completely automatic
with the help of an electronic computer. Glass plates are moved on a roll conveyor, getting
first into the heating furnace, where the temperature is maintained with the help of electric
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resistances disposed above and below the conveyor and it is automatically adjusted. The
temperature can exceed 650°C. It must be chosen so that the glass plate would not get
distorted and that the inferior surface would not get imprinted with the conveyor‘s roll tracks.
The furnace is coated with refractories that can stand thermal shock, for example glass plates
of SiO2 and isolated with ceramic fibres, and the rolls are made of ceramic with very smooth
surfaces. After passing approximately 37 m through the furnace, the plates must reach the
temperature necessary for hardening, which is controlled at the end of this area with the help
of a pyrometer. If any deviation from the optimal temperature is detected, as the pyrometer
indicates, it will automatically command the rescheduling of the temperature curve in the
furnace. Then, the plates will pass through the security system, where on a length of about 25
m they will be highly cooled up with compressed air blown through nozzles disposed above
and below the glass plates. The pressure of the cooling air is modified along this area in three
steps, between 1800 mm H2O and 100 mm H2O.
We mention [1] the usefulness of achieving an atmosphere of SO2 (about 300 ml/min) in
the furnace, obtaining the hardening of the plates by depleting alkaline oxides in the
superficial layer, as well as a lubricating effect on the rolls, reducing the risk of imprinting
their tracks on the inferior surface of the plates.
In this type of installation there can be hardened plates having dimensions of up to 2 x
2.5 m, with thickness between 3 and 12 mm. In the case of plates of 1000 x 1200 x 0 mm
productivity reaches 250 pieces per hour.
Hardening installations working on this principle are exploited at the Glass Pane Factory
in Medias and Buzau.
In the vertical installation the glass plate is suspended to a device with several sharpened
tips (claws) which ingress in the recess pairs made on both sides of the plate, along one of the
edges. The device holding the plate in vertical position moves along on a monorail, ingressing
on to the side of an electric oven, (fig. 1)[1], where it heats up to the necessary hardening
temperature, then, a new movement leads the glass plate between two vertical metallic walls
with wholes of about 5mm diameter, disposed regularly at about 25mm distance from one to
another, through which compressed air is blown.
Fig. 1. Section through a plate heating vertical furnace:
1 — thermal isolation ; 2 — refractory ; 3 — resistances; 4 — conveyor rolls; 5 — conveyor ; 6 — clips; 7
— glass plate; 8 — closing lid of the furnace.
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The two perforated walls execute oscillating moves in relation to the glass plate so that
the airstream describe circles, thus covering more equally the surface of the glass plate. Both
air pressure and the distance between the perforated walls considerably influence the
hardening quality.
For curving the glass plates used in front of or at the back of vehicles there can be used
an installation similar to the one described earlier, after the furnace, it is provided with a press
whose working principle is presented in fig. 2 and which allows the production of complex
and non-uniform curves. Then, the curved plates are annealed in a furnace having this purpose
or they can also be hardened. For uniform curves there also be used moulding, respectively
distortion under its own weight at an adequate temperature, on a metallic frame having the
wanted form and curve (fig. 3)[1]. Curved plates can be used non-tensed, annealed, and
secured.
While for lateral windows of vehicles, hardened plates are generally used, 4 – 5 mm
thick; they clearly tend to 2.5 – 3 mm for windshield and back window there are more
variants, in some countries the law allowing only one of them.
Fig. 2 The principle of curving by pressure:
1 – heated glass plate; 2 - monorail; 3 – holding clips; 4 – press which also serves for hardening; 5 –asbestos
sealing; 6 – openings through which compressed air is blown out; 7 – curved and hardened plate.
Fig. 3. Section through the furnace for curving through modelling:
1 – thermal isolation: 2 - refractory; 3 — heating resistances; 4 – moulding form cart
The most appreciated windshields are of two annealed glass plates, 3mm thick, having
identical curves, joined through a Polyvynil Butyral film (butafol) 0.76 mm thick [1].
Windshields considered better are made up of glass plates hardened in a different way: the
interior one in highly hardened, while the exterior plate is less hardened. In the fifth case, such
a windshield is hit by a stone and eventually the exterior plate is broken, the chips are
relatively large so that they do not diminish visibility that much, the interior plate remains
intact and the stone does not get inside. If the interior plate is broken, in case of an accident,
by hitting it with the head, the result is very small round chips which do not produce serious
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wounds, and the head will not get through the windshield except for extreme cases, when the
entire windshield is plucked out of the frame.
Windshields composed of only one hardened glass plate are the most disadvantageous,
being even prohibited in some countries. In case of getting broken, the mechanic energy is
released with a strong rumble which may disorient the driver. If the broken glass plate does
not fall from the frame, the small chips make it almost opaque, sometimes totally reducing
visibility. This last inconvenient can be eliminated by a differentiated hardening so that in
front of the driver there would be areas with lower tensions which may get less opaque in case
of getting broken.
In order to maintain the mechanical properties, there are made some special tests. Thus,
when broken the hardened plates must form between 50 and 350 chips on a surface of 25 cm2.
For windshields there is tested the resistance to mechanical shock and to penetration with
steel balls of 0.227 kg and 2.26 kg and with a piece of a head‘s form weighting 10 kg. From
an optical perspective, the windshield must have a high transparency, without distorting the
image when looking through it and without producing a secondary image.
In the case of passenger or military planes, the conditions set for certain windows are
even more demanding, and thus there are required pieces made up of 4-5 plates of differently
hardened glass and joined with Polyvynil Butyral films.
According to the use conditions, some windows must ensure good visibility at low
temperatures, when steaming and even frost (icing) come up. One of the solutions used
consists of the electrical heating of the pane using resistances set on the glass. One variant is
silk screen printing some silver conducting wires built in a fusion agent. A number of 12 such
wires having a certain type of section ensure the heating of the rear window of an vehicle
without diminishing too much visibility [1, 2,3,4]. Another possibility consists of inserting
some heating wire-resistances between the plates of a triplex pane. A third solution consists of
using a semiconducting SnO2 film or by spraying a SnCl4 solution in water or alcohol.
Depending on the film thickness, resistivity varies between 20 and 70 ohms and the light
absorption does not exceed 20%. Electrical current is applied by means of silver electrodes set
near the window frame. The semiconducting film is electrically protected and insulated with
transparent varnish. If for other purposes the plates are heated to higher temperatures, SiO 2,
TiO2, Al2O3 electro-insulating films are deposited.
Another important problem which arises in the case of vehicle windows but also for the
windows of civil buildings is preventing the penetration of intense solar thermal radiations
during the summer or in those hot areas around the Globe. This challenge is achieved in two
main ways: producing thermo-absorbent glass plates or depositing reflector and caloric
radiation absorbent films on the normal glass plates.
Conclusions
The main qualities required for pane glass are the reduced tendency to crystallize and
high chemical stability.
The two technological methods have multiple advantages:
1. the technological method consisting of sticking two glass plates on an elastic or
transparent plate or material – results in the triplex plates, whose breaking forms chips that
remain stuck on the intermediary elastic material.
2. the technological method consisting of hardening the plates, in which case if broken it
forms small chips with non-dangerous rounded tips and edges.
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References
[1] Baltă P., Glass Technology, Didactic and Pedagogical Publishing House, Bucharest,
1984
[2] Velea V., Pane Technology, Technical Publishing House, Bucharest, 1965
[3] Velea V., Light Industry, 30, 6 (1983), p. 265-270
[4] Smărăndescu A., Marian T., Light Industry, 29, 3 (1982), 112-116
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THE SOCIAL IMPLICATION OF INDUSTRIAL DESIGN
Prof. dr. arh Dan Horia CHINDA, Dhc Creative Ltd. Co Florida SUA,
[email protected]
Abstract. The social function of design becomes indisputable. In order to define the social involvement/impact of
form I shall therefore recall the manner in which products influence man. And I shall do this by focusing on the
social involvement, which manifests itself as a result of the direct, interactive relationship between user and
product.
Keywords: design, art, perception
1.Introduction.
A new product of design communicates to its consumer inside this equation, by two
ways:
- the surprise factor triggered by this visual perception, directly proportional to the
design creativity built inside the shapes, reflecting the feeling, the impression which shapes
create upon man,
- the psycho aesthetic factor, which defines, in fact, the way in which the product is
consumed. The aesthetic perception and the possible pleasure created by this feature cannot
be lived separately by the psychological effects which the shape and the color have on the
human psychic.
The idea which I want to underline here is that the product itself can exist only within
a social activity context, a context of its interaction with man/ the human kind, nevertheless
within the interaction between men using a certain product. Considering that men
generally manifest themselves within social groups, smaller or larger, and that their activity
has mainly a social character, and considering that the product by its occurrence creates new
relations between men, developed and sustained by the simple use of the product, defining
themselves as systems of communication and object oriented connection. The product has
the ability to create new bridges, sometimes connection bridges unforeseen by either the
designer or the producer, nevertheless found by consumers by this use of the product,
therefore becoming a social vector.
Thus, the interest focus in designing design products falls not only on their formal
shape/image, but also on their use destination and on the relations thus generated, defining the
use principles for new objects.
As I have already stated, the functional object appears at a first analysis as a use need
of an individual, the object (let‘s call it product), confirmation relationship being defined by
the need which this person feels; whether the need for this product to appear on the
consumption market is of social level, as this is the definition of design understood as
production, we refer to serial production, mass production, destined to everyone. Although the
product directly answers to an initially defined individual need which is subsequently
extended to the need of social groups of consumers, it becomes hard to anticipate exactly the
effect derived by the occurrence of certain products, as well as of the relations generated by it,
their amplitude, complexity and diversity.
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Bicycles in themselves answer the human need of transportation, of movement,
exploration, physical exercise, developing in the same time social relationships, grouping
people urged by the same interest, initiating its practice in groups of people.
We shall distinctly define the quality of design by a deep social content, satisfying
masses of people by its use, functioning as a social link, uniting, and creating new
relationships by and through a certain product. In a direct manner this object oriented
communication concept suggests that satisfying the functional needs, and the aesthetic
perception function on a large scale, at a social level, design becoming therefore a social
vector, supporting and developing new relationships between people, created by the
occurrence and the use of that certain object.
This role regulates and maintains human social relationships, being not only a vector
but also a regulator, a catalyst of social activities. Considering the social-psychological aspect,
the purpose of design shall not be defined as satisfying individual demands and needs,
regardless the definition of these needs as individual as occurrence, by a human – object
direct relationship, but by the creation of certain optimum object oriented mass connection
systems, which shall reflect direct and indirect relationships, individual and mass
relationships generated as such. The object leaves the field of individual semantics meant to
define its identity, extrapolating itself within a social semantic expression, finally becoming
a status quo, a ―brand‖, an illustration of the social state of a certain group. Design can appear
at this moment not as a unifying social element, but as an element of discrimination,
defining various states and social or material levels. It therefore becomes imperative that these
object and sign-oriented mass connection valences be created naturally by the expression of
the human individuality, non-hostile under the equation of a lifestyle psychology.
Moreover, the rich social content of design is even easier to be underlined by the
parallelism between design and figurative art. The fundamental differentiation is relevant for
both the analysis of the genesis of the two forms of aesthetic manifestation and for their final
consumption.
The act of creation itself, in art and especially in the figurative art (visual arts) is most
of the time accompanied by a state specific to the act of creation, an emotional plenitude,
euphoric or dramatic, magnificent or consuming, described by the ancient Greeks as
―catharsis‖. This emotional blending has an extremely heterogenic manifestation, each artistic
personality having a strong expression and therefore, an individually differentiated
manifestation.
Artistic communication is of individual emotional nature,
a message from the creating, sensitive abyss to the world
outside the artist, it is possibly a desperate striving, it is
often a decoding of certain experiences and realities by
emotional religious, ethic, aesthetic filters, and their
emotional individual encoding. Finality is usually
hedonic, finding the joy of artistic expression, spiritual
elevation, the artistic act being usually finalized by the
creation of unique masterpieces. Considering the
consumption of this masterpiece in itself, it shall be at
first of individual, contemplative nature, which can be
accepted or denied by viewers. This contemplation is of
Laocoon, anul c. 175-150 BC
passive nature, detached by the work of art itself, with no
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direct significant interaction, nevertheless and most important, contemplation being defined
not as a direct mass phenomenon, as it does not finally offer any immediate practical utility.
(Example: the Laocoon group).
Opposite to art, design (as architecture) genetically is an extremely complex process,
cognitive and intuitive as well, a process of interaction and analysis, collective and
compulsory interdisciplinary, a process of information decoding and encoding, where strictly
technical elements, such as product function, its engineering and constructive nature, the
production materials and the applied technologies, the ergonomics, the calculus of economic
values, the consumption psychology and the market elements, the marketing get woven in
some miraculous tissue within the designer‘s creative act, who, by using his ―wand‖, defined
by his sensitiveness and aesthetic intuition, nevertheless controlled by an analytic logics,
conduct this orchestra creating in the end a product which contains a message, first of all
visual, of visual perception, therefore aesthetic, which we identify. This identification takes
place first of all because we like the product, (the surprise factor previously mentioned), but
at the same time the product makes us think of its use. This makes the fundamental
distinction and difference between the two manifestations from a genetic point of view. The
finality of this complex process is not a unique
creation; on the contrary it shall be defined as a
mass production, serial production, destined to
satisfy the practical needs of large groups of
people, the consumers. The aesthetic
consumption of this product, even if the first
perception impact is of individual nature,
whether we refer to products which are used by
just one individual, generally manifests as a mass
phenomenon, the product offering in a definite
Chevrolet Kalos manner practical utility to all its users, answering
the needs of a large group of people, therefore,
its appreciation and recognition is a mass recognition, involving consumption of social
character, the same as Architecture.
The aesthetic content blended in the design product is consumed, perceived,
appreciated actively by its use not passively by contemplation, such as art, being consumed
by the use of the object itself, by the dynamics of its functionality. The same as architecture,
design has a deep social character, nevertheless democratic by offering equality by its
destination, whether we talk of identical products. For example, when using a car type
Chevrolet or Kia, the consumers apply the same principle in the same way, the buying
decision generally defining a group of buyers of the same material condition, the buying price
being in fact the major factor of the buying decision. Moreover, the car connects the same
social human category defining their need, and carrying the social image, which the car
projects upon them.
In the same time, the car itself, appears as an extremely discriminating product by its
variety of comfort, value, style and social class implied.
Of course that by using a Ferarri, Jaguar, Porsche 911, or a Pagani, discrimination becomes
obvious, the decision and the possibility of buying this type of car reflecting a level, which
just a small group of people can afford. It is apparently a paradox that the same functional
program should equally reflect the comfort offer of the masses of consumers and the
discriminating character, of social differentiation in the same time.
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A relatively good watch can be bought for 50- 100 dollars. And again a watch, maybe
a little better than the first, costs thousands of dollars. The functional quality in itself, the
purpose of the product, which is to measure the time, is satisfied as compared to the real need
of the theoretic consumer. Both watches are bought, the sellers of both products illustrating
the extremes of social welfare, selling continuously, thus producing the desired profits.
New products determine social changes. They bring new habits in human life, they
change the systems of values, lifestyle, moreover, the communication relationships and the
reports between people. The new product, by answering specific well defined needs brings
comfort in the consumer‘s life; as an immediate result, nevertheless collateral, comfort
determines changes which shall project into the general life of the consumer, as well as into
their interaction to the others.
I could illustrate this theory better by
analyzing the big star in our life and
design: the car. The car in itself has a
spectacular evolution and trajectory in
the history of design products. At the
beginning, the car was thought of as a
new type of transportation device,
destined to be able to cover larger
distances, in shorter periods of time,
though having the privacy, the
flexibility and the motion freedom,
which the train could not offer. Nobody
could imagine in the 40‘s ‗that the car
would become a social symbol of a
certain extremely unique welfare, expressed by extravagant shapes, with chromate body
types, extremely expensive. Two decades later, people began to fly, to rent cars for their jobs,
the car beginning to lose its fashionable star place, and became less attractive. The implicit
power, the social position were no longer reflected by the car in itself, which ceases being a
unique symbol used to reflect the owner‘s social position, and becomes an average mass
transportation means. The car gains its quality of generalized transportation means, a type of
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individual and collective service and less a ―social label‖. The extremely rich people who
previously have publicly demonstrated their condition by buying cars started to buy ships,
yachts, helicopters and other ephemerals. But, following the mass joy, which the car has
offered for several decades, there has come the fear, which usually accompanies the joy: the
carbon monoxide, which destroys the ecological balance and the lungs of the humans who
have created the car. Over almost 100 years of existence, the car has gone from a product
initially used with admiration, intimidation and respect, to a demonstration of power, speed,
arrogance and especially the ability to consume fuel, equipped by extremely, unreasonable
powerful engines, which have finally become instruments of destruction and pollution.
The new electric, hybrid cars appear timidly, suffocated by the powerful jackals of the
automobile production who feel threatened, nevertheless these new vehicles are handicapped
at the same time; the chance to rapidly conquer the market is limited by the low speed, unable
to exceed 100 km per hour, speed which generally cannot satisfy the large community of car
drivers. Mentioning their small dimensions as well, which determines a diminution of comfort
– a factor being decisive in America -, the success becomes smaller.
Beyond these results impossibly to be predicted, there are other issues triggered by the
creation of the car: a complete change of people‘s lifestyle, by dramatically increasing the
stress level, by increasing the sacrifice of human lives to over 100.000 people a year. The car
completely changes man‘s philosophy and lifestyle implicitly; it more and more replaces
walks, man becoming more and more sedentary. As an immediate result of sedentariness,
there are health problems also. The creation of the car has developed a mass movement in the
USA, the ―Wheel Houses‖ movement, which was initiated at first as a form of entertainment
and recreational destination, but which rapidly turned into a social definition of those who do
not have enough money to buy a real house and wish to live independently.
These people create communities, which are usually located at the peripheries of
towns, equipped with electricity and common toilets. Unfortunately these people are of low
education, where alcohol, prostitution and drugs are blooming, already defining a certain
social category widely spread in America, commonly known as ―trailer trash‖ .
The effects of television, of music devices and entertainment devices (entertainment
centers), CD, DVD, MP3, computer games and everything representing the permanently
innovating technology have determined a series of dramatic changes, even radical in the
activities of the individual in themselves, in family and society. The TV programs bring
everything human species desires, from information to music, concerts and movies, from
western to classic movies, porno and thrillers, everything attracting man who loses their
mobility as individuals, who does not read any longer, they receive information on the history
or geography channels, who stays and remains on a surrogate Readers‘ Digest education type,
―summaries on books‖ having an effect of immediate satisfaction. Nevertheless, beyond these
aspects, which are the prices of the education of the individual caught in the TV age ―net‖,
there are even deeper consequences, which are paid by health. In America, the average time
spent in front of the TV, namely unmoved on a relatively comfortable sofa, is of 3-5 hours a
day per person! This lack of activity, besides the inherent ―intellectual‖ slowdown generates
obesity, heart diseases and other mental and physical deficiencies. Individual aspects trigger
social communication issues, modifying the relationships between people. Romantic sideway
walks have been rapidly replaced by watching a last minute movie, the owner of the house
inviting their friends, offering fast food, drinking, and smoking. This could be enough to
determine addiction: man in front of the TV set having an empty look, the remote- control in
one hand, the fast food in the other, chips and the bottle of beer, Coca-Cola; he falls asleep
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late at night, hoping to get what he does not know and cannot even imagine, this waiting
paralyzing the thirst of information, as this media system brings on the sofa already digested
information, generating, besides the physical obesity, a metal obesity, psychological obesity, a
flattening of the generous definition of the human being spirituality .…Sleep loses much of its
rest value and natural healing, its hygiene being completely neglected, the world stress
transmitted by the TV shows being deeply rooted into the human psychic, humans who begin
their night sleep on the coach, the first several hours, then tired, goes to bed (luckily!), thus
generating diseases related to the lack of sleep...in the past, long ago, we had to move to
switch channels, now we have remote control, so we do not have to lose energy by getting up
at least for this …
Examples could have an infinite number. What is important is to understand the
relationship between the new product and the consumer.
There is, obviously, a great ethic responsibility: we invent and we change the
product, which in its turn changes our life. It becomes important that designers should
responsibly think of this aspect; anticipate the issues created by the qualities of the product
and their derivations. Should he be able to anticipate undesired changes? It is a question the
answer of which I do not know exactly, but I wish with all my heart that all the designers
should be aware of this moral responsibility and be able to stop the destruction of man and of
the environment, they can save the planet or at least prolong its agony.
It is certain that the designer plays an educational role in civilizing the consumers, by
the new level of comfort offered by the created products. We can dare say that design is a
measure of civilization and this we can say by underlying the difference between the lifestyle
of the city people, as compared to the lifestyle of the village people, despite the culture level,
their behavior being influenced by the urbanization changes which influence the individual,
by the comfort which forces people to manifest themselves in a certain way, although they do
not have any merit in this, but simply reflect the level of civilization to which they have been
taken by using products specific to urban civilization, it becomes a kind of floating into that
civilization... Design can contribute to educating society not only by offering ―civilizing by
using‖ the most recently created objects, the most fashionable ones, indirectly educating
though, by the communication content which the object itself displays. Being the result of the
simultaneous synthesis of the culture moment and of the technical civilization, including
besides the representative technical elements specific to the product aesthetic elements also,
elements of art and fashion, design is in fact the answer, the aesthetic pulse, I should say, to a
particular moment of that society. The educational role of design is indisputable. Sometimes
the question is: do we wish this consumption society ―civilization‖ where modern products
and technologies manipulate us, consciously or unconsciously?
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RISK BASED MAINTENANCE IMPLEMENTATION OF
REGENERATION BOILER AT S.C. ―SOMES DEJ‖ COMPANY
Phd.Eng.Daniela Dorina FULOP, Technical University, Cluj-Napoca, Romania
[email protected]
Prof.Dr.Eng.Tiberiu Rusu, Technical University, Cluj-Napoca, Romania
[email protected]
Prof.Dr.Eng.Dan Viorel, Technical University, Cluj-Napoca, ROMANIA
[email protected]
Dr.Eng.Istvan FULOP, SC Mecsom SA Dej, Romania
[email protected]
Abstract: In the paper the authors present some characteristics aspects regarding the implementation of Risk
Based maintenance methodology in S.C.Somes Dej company, and their experience in this field.
Keywords: maintenance, risk, regeneration boiler, risk assessment
1. Introduction
The regeneration boiler is a technological installation of sodium salt waste from
concentrate Black Lye, resulted from wood boiling process, resulting dissolving pulp.
Boiling the sodium salt are resulting 50 tons vapor at the 40 bar pressure, which is used
in the pulp and paper manufacturing process. According the technical directions from the
ISCIR collection, the regeneration boiler is considered under pressure installation from A
category, with maximum level risk.
In the last years, at the pulp and paper S.C. ―Somes Dej‖ Company, in the field of
proactive maintenance, was successfully implemented risk based maintenance of installations
with high level risk, such as the regeneration boiler.
The implementation stages of risk based maintenance at the regeneration boiler are the
following:
- identified the component elements and functions of the equipments;
- identified the probability that this component element functions not accomplished, and the
possible damages of the equipment elements;
- the analysis of probability and risk produce at the equipment elements of sodium salt
boiler;
- identified the causes of damage risk appearance and solutions to avoid the risk
appearance;
- establish maintenance process for equipments protection avoiding the failure risk
appearance and planning the specific demands for avoiding risks.
The risk based maintenance and continuous monitory of equipments stage are in close
interdependence, which is the only counterwork solution of unexpected breakdowns
appearance. The determination produced risk of damage and technical unexpected
breakdowns are realized with the risk matrix depending on gravity and probability of damages
appearance.
The risk matrix is presented in figure 1.
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ECONOMIC
TECHNOLOGICAL
ENVIRONMENT
THE PROCESS SAFETY
SECURITY AND HEALTH OF WORKERS
RISK
PROBABILITY
Huge risk
Big risk
Medium risk
Low risk
Fig. 1 The risk matrix
The risk analysis of damages is based on equipment analyze and the following
components of society integral management:
- the security and health of workers;
- the process safety of installations equipments;
- the actual environment legislation;
- the technological aspects;
- the economic-financial aspects.
2. Improving the equipment’s reliability applying the risk based maintenance at the
regeneration boiler
2.1. The black lye pump of regeneration boiler
The regeneration boiler is continuous feed with concentrated lye pump type ABS
NB-125-100, driven by 22 kW/1500 rot/min electric engine.
By analyzing the historic of the black lye pump in 2006-2007 years, the total duration of
the unexpected breakdowns was 280 hours and the main causes were identified, as presented
below:
- pump bearing deterioration: 48%;
- the born of electric engine, because of the excess load, caused by the restriction of the
pumping tubing, according with lye pump debit adjusted, which entered into the boiler: 28% ;
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- non-sealing up problems caused by worm sealing destruction from shell and axle pump:
14%;
- the breaking of pump hold down screw, through high vibrations caused by non-adequate
base of the electric engine and pump in the base of structure: 7%;
- other causes: lubricate missing, braking of the rubber blades from the couple, rotor
disequilibrium: 3%.
The black lye pump is equipped with NU 312ECP bearing, on the rotor side, and a tow
6313NR bearing on the electric engine side. The proposed solution for reducing the
deterioration pump bearing was replacing the radial roller bearing 6313 NR with radial-axial
roller bearings 7313 BECBP. Meantime we replaced the pump worm sealing with mechanical
sealing, a new pump base was fixed in the structure by casting process, proceed from one
fixing pump mounting shoe, alignment of the pump electrical engine and laser centre device
was made, and the replacement of the manual valve from pump delivery with automatic
valve.
For protecting the electrical engine from additional load the solution is assembly one
frequency converter which adjusts the electrical engine speed by the black lye capacity,
barred from operator monitoring board.
After functioning of pump from January 2008, the unexpected breakdown decrease with
88%.
Fig. 2 Black lye pump
2.2. The cooling water feeding pump of the regeneration boiler
The OLT 100 pump with 10 superposed rotors assure regeneration boiler feeding with
cooling water, for cooling the tube from furnace boiler. The pump is driven by 250kW and
3000 rot/min electric engine.
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By analyzing the historic of the boiler feeding pump with cooling water in 2006-2007
years, the total duration of the unexpected breakdowns was 280 hours and the main causes
were identified:
- bearing deterioration because of the working with restriction pump delivery according with
water debit adjusted: 41%;
- electrical engine bearings deterioration because of lubricate missing;
- pump rotors deterioration because of rotors solid particles vibration and penetration getting
through.
In January 2008 at the planed repairs was made the following modifications:
- replacement of the valve from pump delivery with automatic valve;
-the assembly of frequency converter which assure the electrical engine functionality at
variable speed by the water capacity bared from board;
- assembly automat lubrication system on the electric engine bearing;
- assembly the sieve filter on pump admission for solid particles storage from the water;
- rotor dynamic balance at 3000 rot/min speed in assembly state on pump axle.
Until now this pump rotors balance was individual make without rotor-axle assembly
balance.
- was process from one fixing pump mounting shoe;
- alignment of the pump electrical engine and laser center device;
- replacement of admission location line and pump delivery, such as the attachment flange to
be in parallel with pump attachment flange.
After bring into service the regeneration boiler water feeding pump the unexpected
breakdowns decrease with 78%.
Fig. 3 Water feeding pump
2.3. Installations and electrical equipments inspection
Installations and electrical equipments inspection at regeneration boiler is periodic
inspect and carefully observed, because is a very complex equipment with high level risk.
For optimal working of installations and electrical equipments, the periodic inspections
are at exact time based on risk level, using the infrared thermograph process.
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The measured dates are compared with precedent results, following the electrical
equipments time evolution, interfering when the equipment state arrive at the critical level for
safely functioning, security and health of workers.
Fig. 4 Installations and equipments thermograph process
2.4. Vapor tube and pressure lye inspection
The 40 bar and16 bar vapor tube, as well as the concentrated black lye are periodic
inspected: measuring the tube thickness with the ultrasound equipment, welding inspections
using gamers and incisive liquids, analyzing metallographic structure of tube material using
non-destructive processes.
Pressure tubes are authorized by ISCIR and periodic inspected by IT ISCIR Inspect, for
the re-authorized at periods of 4 years. According as the level risk of the pressure tubes is
periodic inspect tow times per year, during the planed maintenance.
Table 1.
Tube pressure sections
No. Section Pressure Thickness Minimum Measured Measured Measured
code
[bar]
conform admissible
value
value
value
project
thickness
[mm]
[mm]
[mm]
[mm]
[mm]
1 401111
40
14
9,8
13,8
13,8
13,7
2 401112
40
14
9,8
10,8
10,4
10,3
3 401113
40
14
9,8
10,1
9,9
9,8
4 162001
16
8
5,6
7,6
7,5
7,5
5 162002
16
8
5,6
5,9
5,7
5,6
The pressure tubes and installations inspection has the following stages:
a) Detailed documentation realization regarding:
- component elements of pressure installations;
- breakdowns history and frequency;
- repair description of breakdowns;
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- dates regarding the technical state of installation and pressure tubes.
b) Measurements and inspections realization at installations and pressure tubes
c) Results interpretation and analysis obtained by the measurements
d) Proposed solutions for eventually deteriorations at installations and pressure tubes
The pressure tubes are divided by sections, marked, counted, inspected and observed in
time, regarding the level risk.
3. Conclusions
In order to assure a good maintenance of giant industrial equipments it is necessary to
prepare one detailed program according the specific rules and experience in this field.
ACKNOWLEDGMENT: This paper was supported by the project "Doctoral studies in
engineering sciences for developing the knowledge based society-SIDOC‖ contract no.
POSDRU/88/1.5/S/60078, project co-funded from European Social Fund through Sectorial
Operational Program Human Resources 2007-2013.
Reference
[1] Alexandru, I. Metode de evaluare a riscurilor, Universitatea Tehnică Gheorghe Asachi,
Iaşi, 2007
[2] Barratt M., Proactive maintenance, SKF Reliabilitz System, San Diego, 2003.
[3] Nagy I., Müszaki diagnosztika: Termográfia, Delta-3N Kft, 2007.
[4] Wintle J.B., Kenzie B.W., Best practice for risk based inspection as a part of plant
integrity management,TWI and Royal&Sun Alliance Engineering, 2001.
[3] Băbuţ, G. (2007). Metode de evaluare a riscurilor profesionale, Universitatea Petroşani,
2007.
[4] Fulop, I., Gyenge, Cs., et al., Some practical aspects of Risk Based Maintenance
implementation in paper industry, 9th MTeM International Conference, Cluj-Napoca, 2009.
[5] Tischuk, J.L., The application of risk based approaches to inspection planning, Tischuk
Enterprises, 2002, Aberdeen.
[6] ***, Guide to risk assessment requirements, HSE Books, 1996, ISBN 0717615650.
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METHODS FOR DETERMINING THE OPTIMAL
SOLUTION FOR THE REHABILITATION OF CEMENT CONCRETE
ROAD PAVEMENTS.
Lecturer dr. eng. GAVRIS Ovidiu
Faculty of Civil Engineering, Technical University of Cluj Napoca,
[email protected]
Abstract : Rehabilitation (restoration) of cement concrete pavements raises a number of problems for
road engineers because of the rigidity of the structure. Solutions used generally fall into two categories:
one which implies milling the concrete tiles (recycling them) and another solution which involves covering
the existing pavement with asphalt road systems that behave well under traffic.
This article aims to provide a multi-criteria analysis method regarding the choice of intervention in such
sectors.
The analysis will take into account three elements:
- the cost
- the degree of pollution of the technology that will be used
- the duration of execution
Each criterion will be graded according to an established algorithm and a ranking of the possible solutions will
be made, based on this score.
Keywords: multi-criteria analysis, road rehabilitation, cement concrete, road system
Introduction
Cement concrete pavements were very frequently used between 1970 and 1980. This was
due to the following reasons:
- the abundance of natural resources throughout Romania ( aggregate and cement)
- the lifespan of rigid pavements is higher with approximately 10 years than the elastic ones.
- the production of cement concrete pavements was less polluting and less expensive than the
asphalt pavements.
The structure of cement concrete pavement is much simpler than that of the asphalt
because it has only the foundation layer, made of granular material, on top of wich cement
concrete is applied in one or two layers depending on the thickness of the concrete road.
Between 1995 and 2010 the lifespan of many road sectors had expired (more than 25 years
have passed since they‘ve been built). In these conditions, with the upcoming road
rehabilitation programs, the matter of repairing them was raised. However, rehabilitating
these areas proved to be quite difficult. The rigid system could be replaced, reinforced with a
rigid system, turned into a semi-rigid pavement, or reinforced with asphalt layers after taking
special measures to reduce tensions and deformations at the base of the asphalt layers so that
they dont exceed the allowed values. The frequently used solutions are:
A. milling the concrete tiles and integrating the milled material into the foundation then
spreading the other layers as resulted from the calculus of the road structure;
B. Repairing the damaged tiles (including their replacement if necessary) and the joints
between the tiles, applying a geocomposite material that improves the strain and
fatigue behavior of asphalt mixtures and laying the asphalt coating.
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C. Loosening the tiles ( micro-fissuring the concrete), laying a layer of granular material
with the role of preventing the transmission of cracks and spreading the asphalt layers
as resulted from the calculus of the road structure.
The designing engineer and especially the recipient, are faced with deciding which of the
three solutions is more effective. Governmental Decision HG 28/2008 requires to compare at
least two solutions for rehabilitation and the designing engineer must sustain the most
advantageous. As a consequence of this fact the article aims to provide a method of
determining the most effective intervention solutions based on multi-criteria analysis. On one
hand the method will ease the burden on the engineer in supporting the solution and on the
other hand the comparison will help convince the recipient that he has chosen the best
solution.
THEORETICAL PRESENTATION
The theoretical presentation and the case analysis will consider the following multicriteria analysis items:
The cost
The environmental impact
The duration of the execution
Each criterion will be awarded 0 to 100 points and then it will be graded according to its
importance in investment economics. Further the scoring for each criterion will be presented:
Cost
This criterion was chosen because it reflects the investment effort, by giving at the same
time the cost amount for each analyzed alternative. The cost of execution will be determined
for each possible solution per square meter and then it will be graded according to the
following relationship (1):
Cost min
 100
(1)
Cost optioni
The environmental impact
The following criteria have been considered for the comparative analysis of the studied
options:
1. Quality of the air during the execution
2. Noise level
3. Surface water
1. Quality of the air
The criterion takes into account dust emissions depending on the technology of execution.
The factor has to be considered because some road sections are crossing urban areas. Some
other pollution sources are the hazards of hot asphalt. The latter are but inevitable for any
chosen option, however their effect on the quality of air is a minor one because the emission
are of short duration.
2. Noise Level
This item quantifies noise pollution of execution technologies. Besides the noise of the
machinery this point should also include the vibrations that are produced during the road
rehabilitation and their effect on surrounding buildings.
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3. Surface water
Surface water, due to rain, will be collected in the designed ditches and will be led to an
emissary. These measures have to be taken in order to avoid the presence of water in the road
area that would otherwise favor the emergence of holes during freeze-defreeze times and
poor adhesion to the road surface.
The quantification of the environmental impact was made using a notation scale, from ―-3‖ to
―+3‖, for each criterion as follows:
- ―-3‖ - important negative impact which requires redesigning or giving up the project;
- ―-2‖ - important negative impact which can be minimized by taking adequate measures;
- ―-1‖ - less important negative impact;
―0‖
- no impact whatsoever ;
- ―+1‖ - reduced positive impact;
- ―+2‖ - important positive impact;
- ―+3‖ - very important positive impact;
In the end, the marks for all criteria will be counted and the option‘s mark will be obtained.
The
score
for
each
option
will
be
calculated
as
follows:
- 0 when the sum of the marks is less than ―-10‖, (the sum of the marks +10) x5 when the sum
of the marks is between ―-10‖ and ―10‖ and 100 for the marks summing more or equal to 10.
The duration of execution
This criterion will evaluate the speed of execution, with direct influence over when the traffic
can be resumed. The score will be the ratio between minimum time for rehabilitation of a
square meter (Tpmin) and current time in another variant (Tpcurrent) (2).
Tp min
100
(2)
Tpcurrent
Application
Considering the above facts the three rehabilitation solutions are compared in order to
establish the best option for intervention.
Cost
Solution A
1.Surface Course
Milling
m2 1
- 50 RON
3
Crushed stone
m 0.2
- 20 RON
2.Base course
Base course
tons 0.144 - 36 RON
Surface course
tons 0. 096 - 24 RON
3.Crushed Stone
Total for solution A
130 RON/m2
4.Milling
1.Surface Course
2.Base course
3.Geocomposit
Solution B
Repairing the
tile
m2
0.15
- 15
RON
4.Repairing
the tile
m2
16 RON
Base course
273
tons
Geocomposit
1,05 -
0.144 - 36 RON
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Surface course
tons
Total for solution B
0. 096 - 24 RON
91 RON/m2
Solution C
Loosening the tile
m2
1
- 8 RON
Crushed stone
m3 0,2
- 20 RON
Base course
tons 0.144 - 36 RON
Surface course
tons 0. 096 - 24 RON
Total for solution C
88 RON/m2
1.Surface Course
2.Base course
3.Crushed Stone
4.Loosening
the tile
The score for these criteria is presented in table 1.
Table 1
Criterion
Cost
Option
A
67,7
Score
Option
B
96,7
Option
C
100
Percentage %
%
Option
A
33.33
22,34
Option
B
31,91
Option
C
33,33
The Environmental Impact Quantification
Solution A : High noise pollution and air pollution due to dust emanating from milling.
Solution B : Reduced air and noise pollution.
Solution C : Reduced air pollution, but high noise pollution.
In each of the three solutions surface water is properly disposed of. The score of the criterion
is presented in table 2.
Criterion
1. quality of the air
2. noise level
4. surface water
TOTAL
TOTAL SCORE
Option
A
-3
-3
3
-3
35
Option
B
1
1
3
5
75
Table 2
Option
C
1
-1
3
3
65
The duration of execution
Solution A : The time for road milling and spreading of layers.
Solution B : High duration of execution because of concrete strenghtening time.
Solution C : The duration of execution is very rapid and practically only the time necessary
for spreading the pavement layers is taken into account.
Table 3
Criterion
Duration of
execution
274
Option
A
50
Score
Option
B
14.28
Option
C
100
Percentage %
%
Option
A
33.34
16,67
Option
B
4.71
Option
C
33.34
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Final score
Criterion
Cost
Environmental
impact
Duration
of
execution
Total
Option
C
100
Table 4
Percentage %
%
Option Option
A
B
33.33
22,34
31,91
Option
C
33,33
75
65
33.33
11.55
24.75
21.45
50
14.28
100
33.34
16,67
4.71
33.34
152.7
185.98
265
100
50.56
61.37
88.12
Option
A
67,7
Score
Option
B
96,7
35
By comparing the three solutions, based on the presented criteria, solution C appears to be the
most advantageous (table 4). Technically the solution has some restrictions in areas where
spreading new layers over the existing road structure is limited. In this situation, in the
restricted areas, solutions A, or B are considered.
CONCLUSIONS
Multi-criteria analysis is a major aid in decision making. As observed in this paper the
methodology is easy to apply. The criteria to be considered remains at the discretion of those
who are depending on the purpose of analyzing the investment. Solution A may prove to be
challenge for those who build construction machinery, because if they can remove the
inconvenience of air pollution and tanking into account that the milled material is integrated
directly in the foundation layer, solution A would be the most advantageous.
REFERENCES
1.O. Gavriş
―The Settlement of the Optimum Intervention Solution Based on the MultiCriteria Analysis Regarding a Road‖. International Conference Constructions 2008 /C55,
ActaTechnica Napocensis, Section: Civil Engineering-Architecture nr. 51, Vol. IV, – May
2008, Cluj-Napoca, Romania ISSN 1221-5848
2. The Governmental Decision HG 28/ 9 Ian. 2008
3. The Regional Operational Programmed 2007-2013. Priority Axis 2 – The Regional and
Local Improvement of the Infrastructure
4. Romania – Technical Assistance for the Elaboration of the General Transport Master Plan
- site of Ministry of Transport ( MT)
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FACILITES FOR ELECTRIC DETONATORS TESTING, ON HIGH
TECHNICAL LEVEL AND IN SAFETY CONDITIONS REGARDING
OF REQUIREMENTS OF EUROPEAN STANDARDS
Eng. Edward GHEORGHIOSU, INCD-INSEMEX, [email protected]
Phd.Eng., Attila KOVACS, INCD-INSEMEX, [email protected]
Eng. Sorin BORDOŞ, INCD-INSEMEX, [email protected]
Abstract: To place on the market of explosives for civil use must comply with the essential safety requirements
applicable. The evaluation of products with the essential safety requirements, is achieved by comparing the
obtained results do the tests on laboratory, equipment test conditions required ensure
by the harmonized European standards.
Keywords: explosives for civil use, electric detonators, harmonized standard, the test stand
1. Foreword
To place on the market of explosives for civil use (including detonators) shall be in
accordance with applicable essential safety requirements specified in the "Directive
93/15/CE" and "Decision no.207/2005".
The products with the essential safety requirements, is achieved by "notified bodies" by
evaluating the obtained results do the laboratory tests performed by applying the harmonized
European standards of families 13630-112 Explosives for civil uses – Detonating cords and
safety fuses, 13631-1  16 Explosives for civil uses – High Explosives 13631-1 25
Explosives for civil uses – Detonators and relays, standards were taken as the SR EN "ASRO
– Standardization Association in Romania".
On basis of the experience gained during the development of specific activity in
explosives for civil use, INCD-INSEMEX certification body meet minimum criteria and the
European Commission was notified as competent in evaluating products in this area.
To obtain notification required infrastructure to test by developing stands and purchase
equipment with which can be to checked the performance and characteristics of explosives for
civil use, in accordance with harmonized European standards.
Test conditions imposed by standards for testing electric detonators, has led to a stand,
presented the contents of this article.
2. Design requirements
When designing the stand should take into account all security measures and health,
both in construction and further, to use in order to provide full safety testing and to cover
them.
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2.1. Design for ergonomics and user safety
Design for user safety. Laws and regulations on labor protection leads the designer to
act responsibly. Security of personnel and the environment are essential requirements to
respond to any technical equipment. The designer must consider the subjective aspects related
to personnel, such as misunderstanding the correct or fatigue, that the equipment designed to
avoid causing injury to a possible mishandling.
Ergonomics. In making the stand was given to maintenance and easy handling,
goodlighting and ventilation of the workplace, the possibility of surveillance equipment
operating parameters, noise, dustiness etc.
The main health and safety requirements in operation of the stand trial are related to:
avoid falling lid, providing work and movement space, to avoid danger of uncommanded
explosion of the electric detonators, excluding the false orders or incorrect handling; ensure
adequate lighnting and visibility; good opportunities handling subassemblies, stability, risk of
rupture of mechanical assemblies, risks due to surface corners and edges, explosion hazard,
avoid gas formation during handling.
2.2. Structure rezistence calculation
The main condition which prevails in the new method is that the test material, in this
case, electric detonators, is necessary to be thermally conditioned at a temperature of 20± 2 C.
Given this requirement, the test stand was built in an area that can be thermally
conditioned according to ambient temperature (heated in winter and cooled in summer).
This led to a partitioning of a building located in a warehouse
In this space to set the location of the stand, separate from the control table by a
soundproof wall.
Stand to gain visibility during the tests was provided in an insulating glasspartition.
Since the tests resulting toxic explosiones, it was necessary to provide for the
introduction of a fan to absorb gases inside the stand and to evacuate to the outeratmosphere.
The initiation of electrical detonators is as a result, the production ofexplosive gases,
and some splinters from desintegretion of detonator tube and pressure generated by the
explosion.
When designing the test stand to experience while in the field, was taken into account
the phenomena described above.
For this stand has collaborated with specialists from the UM Sadu – Bumbeşti Jiu, for
the design, and specialists from UPSROM Petroşani for the construction.
Since they took large safety factors, and has provided a massive construction, the stand
has been built modular and assembled on-site, (Fig. 1-2).
It was designed as explosion pressure to relax in a volume of 3 m3, protected by an
armore of 6 mm steel plate. Previously, the explosion takes place in a mask (cylinder) that has
a lid on top and the bottom is open, just, for the pressure to have space to relax. Splinters
results will fall to the bottom of the stand, which is protected with a rubber mat.
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Fig. 1. Components of the test stand
The stand walls are lined with expanded polystyrene 5 cm thick to reduce blast noise
and of the outside stand is wrapped in iron sheets of thick 2 mm.
Stand resistance calculation was calculated by the mass of explosive that detonates, the
pressure developed by the explosion, explosive density, stand volume.
From calculations showed that the test bench as a whole has to withstand a pressure
0.096 kgf/cm2.
Stand construction is modular, with two sizes of surfaces, the modules being
symmetrical. Front and back surfaces have a size S = 160 cm2, and the side of 74 cm2. Side
surfaces are attached with 10 screws (Fig. 2).
Fig. 2. Construction of stand modules
3. The electric current in the circuit and designing the wires
For each of the 20 cylinders (masks) which detonate electric detonators were installed
two electrical terminals on an isulated support to link wires (conductors) of detonators.
The electrical circuit to initiate electric detonators is designed to be used for testingas
required by European standards according to the procedures for detonators.
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Fig. 3. The stand equipped with electric conductors
From the literature, is considered a resistance of wires take into account themaximum
value of 5 .
In this case the circuit 20 electric detonators in series will have a maximum resistance of
100 .
Knowing that the resistivity of copper is 1.7 x 10-8  x m, and have used 80 m of wire
cross section S = 1.5 mm2 in the circuit connecting the power terminals and control panel was
calculated resistance of this circuit as 0.113 
4. Ventilation and microclimate conditions
4.1. Description of site
Test stand for detonators was placed inside a building in test polygon in this site by
creating a partitioned room dividers insulated plaster and mineral wool.
4.2. Designing of air conditioning
The test procedure requires maintaining a constant temperature of 20 ± 20 C both in the
room and stand. Following test resulting in stand gas and smoke which to be discharged into
the atmosphere without them enter the room
To ensure regularity test required ventilation is necessary to stand out in approx. 3
minutes.
From the literature, outdoor temperatures for calculating ventilation installations and air
conditioning in cold and warm periods of the year for Petrosani are:
• 29°C in summer;
• - 7°C in winter.
For the design of ventilation and air conditioning were considered calculation the
following parameters: the amount of heat came from outside or released on site, heat losses
and consumption of the enclosure, the release of moisture from the site, the release of gases,
vapors and dust, ventilation air flow required for winter season, summer season.
Following the calculations we chose an air-conditioning LG MB 18 AH DUCT
TYPE.with 18,000 Btu / h, which ensures the testing conditions.
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4.3. Choice of ventilation system
Given the recommendations of the literature on the number of air changes for ventilation
of testing, determining factor for general ventilation air exchange (Cs) as of 4 to 6 V (V volume of the enclosure).
Given the fact that ventilation must stand out in approx. 3 minutes, and stand volume
(approximately 6 m3) that is required to develop a fan flow between 16.5 ÷ 22.5 m3/min.In
this respect it is best to choose a type centrifugal fan Vortice Lineo can achieve, that flow at a
maximum pressure of 520 Pa.
4.4. Construction details on the test stand ventilation eyelets
To connect the fan to stand is necessary to perform  250 mm circular cuttings in both
wall and stand in the building wall. The relationship between fan and stand will be a circular
steel pipe 250 mm linear going beyond wall outside the building with approx. 600 mm.
The hole was practiced so that its horizontal diameter corresponds to halfway up the stand,
To reduce the influence of external temperature on the temperature required to be maintained
in the stand and to protect the fan from the dynamic effect of the tests, it achieved a
construction shown in detail 1 (Fig. 4).
Fig. 4. Vent installation location of the stand
Inner wall of the booth, located in the room, saw a circular hole diameter max. 250
mmalso provided with a shutter operated by sliding. This hole is the same height I will
practice the outside, and in the diagonally opposite to it.
Sealing both shutters will be to not allow dissipation of the stand that temperature
andgas migration in the tower room.
After each test sequence to perform maneuvers should be as follows:
• Start the fan and shutter partially open while inside;
• After stabilizing the direction of movement of air inside the booth interior shutter is
fully open;
• After, making ventilation cycle is going to stop opening covers masks and ventilation
5. Conclusion
Achievement test stand test provides the infrastructure for electric detonators checking
requirements of harmonized European standards and creates the possibility of offerings
specialized services for in this sector. This stand is used also to tests regarding standards and
technical expertise involved in producing electric detonators ofunwanted hazardous events.
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6. References
[1] Buzdugan, Gheorghe., "Strength of Materials", Technical Publishing, 1980.
[2] Cristea, A., Niculescu, N., "Ventilation and air conditioning." Technical Publishing
House, Bucharest, 1971, Volumes I, II and III.
[3] Bordos Sorin, "Design and implementation of a test stand staples staples electricalpower
requirements detonanteconform harmonized European standards" – Draft diploma
Universitatea din Petroşani, 2009.
[4] SR EN 13763-1: Explosives for civil uses. Detonators and relays. Part1:Requirements
[5] SR EN 13763-18: Explosives for civil uses. Detonators and relays. Part18: Determination
of series firing current electric of electric detonators.
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MANAGEMENT OF THE ECONOMIC ENTERPRISES
- THE HARD OR THE SOFT APPROACH? Ass. dr. eng. Cătălina IANĂŞI, ―Constantin Brâncuşi‖ University, Tg-Jiu
Abstract: The human side of economic enterprise today is fashioned from proposition and beliefs such as these.
Conventional organization structures, managerial policies, practices, and programs reflect these assumptions.
In accomplishing its task—with these assumptions as guides—management has conceived of a range of
possibilities between two extremes.
Keywords: management, organization, factors, objectives.
1. INTRODUCTION
―It has become trite to say that the most significant developments of the next quarter
century will take place not in the physical but in the social sciences, that industry - the
economic organ of society - has the fundamental know-how to utilize physical science and
technology for the material benefit of mankind, and that we must now learn how to utilize the
social sciences to make our human organizations truly effective‖ as he said Douglas
McGregor in his book ―The Human Side of Enterprise‖ [2]. Any organization, whether new
or old, whether small or big, needs to run smoothly in achieving its set goals and objectives,
which it has set forth for itself. This necessitates that the four functions of management planning, organizing, directing and controlling be precisely understood. For this to happen,
they must develop and implement their own management concepts. There are basically four
management concepts that allow any organization to take control of its destiny and to lead to
a creation of a cohesive organization, which smoothly achieves its objectives.
2. MANAGEMENT− CONVENTIONAL VIEW
The conventional conception of management‘s task in harnessing human energy to
organizational requirements can be stated broadly in terms of three propositions [2]:
1. Management is responsible for organizing the elements of productive enterprise (money,
materials, equipment and people) in the interest of economic ends.
2. This is a process of directing people‘s efforts, motivating them, controlling their actions,
modifying their behavior to fit the needs of the organization.
3. With this active intervention by management people will be persuaded, rewarded,
punished, and controlled so their activities must be directed.
This is management‘s task-in managing subordinate managers or workers.
Behind this conventional theory there are several additional beliefs-less explicit, but
widespread: the average man is by nature indolent-he works as little as possible, he lacks
ambition, dislikes responsibility prefers to be led, he is inherently self-centered, indifferent to
organizational needs and he is by nature resistant to change.
With these kinds of people the enterprise can accomplish only a few objectives. It
cannot be obtain the true performance and the true goals. From this point of view, D.
McGregor said the approach of enterprise management can be hard or soft for the people that
work inside.
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3. THE HARD OR THE SOFT APPROACH?
Conventional organization structures, managerial policies, practices, and programs
reflect the management‘ assumptions. In accomplishing its task-with these assumptions as
guides-management has conceived of a range of possibilities between two extremes.
At one extreme, management can be ―hard‖ or ―strong.‖ The methods for directing behavior
involve coercion and threat (usually disguised), close supervision, tight controls over
behavior. At the other extreme, management can be ―soft‖ or ―weak.‖ The methods for
directing behavior involve being permissive, satisfying people‘s demands, achieving
harmony. Then they will be tractable, accept direction. This range has been fairly completely
explored during the past half century, and management has learned some things from the
exploration.
There are difficulties in the ―hard‖ approach. Force breeds counterforce: restriction of
output, antagonism, militant unionism, subtle but effective sabotage of management
objectives. This approach is especially difficult during times of full employment.
There are also difficulties in the ―soft‖ approach. It leads frequently to the abdication
of management-to harmony, perhaps, but to indifferent performance. People take advantage
of the soft approach. They continually expect more, but they give less and less. Currently, the
popular theme is ―firm but fair.‖ This is an attempt to gain the advantages of both the hard and
the soft approaches. It is reminiscent of Theodore Roosevelt‘s ―speak softly and carry a big
stick.‖
After the base unending planning function, the second function of the management is
getting prepared and getting organized [1]. Management must organize all its resources
beforehand, to put into practice, the course of action, which has been decided upon in the base
function of planning. Through this process, management will now determine the inside
directorial configuration; establish and maintain relationships and also assign required
resources. While determining the inside directorial configuration, management ought to look
at the different divisions or departments. They must also ensure the harmonization of staff,
and try to find out the best way to handle the important tasks and reduce unnecessary
expenditure within the company. Management determines the division of work according to
its need. It also has to decide for suitable departments to hand over authority and
responsibilities.
Directing or leading is the third function of management. Working under this function helps
the management in controlling and supervising the actions of staff [4]. This helps them in
assisting the staff, to achieve the company's goals and also accomplish their personal or career
goals, which can be powered by motivation, communication, department dynamics, and
department
leadership.
The employees, who are highly encouraged and motivated, generally surpass expectations in
their job performance and also play an important role in achieving the company's goal. This is
the reason why managers focus on motivating their employees. Managers come up with prize
and incentive programs, based on job performance and tend to be geared to meet employee
requirements.
It is very important to maintain a productive working environment, build positive
interpersonal relationships and engage in problem solving [3,5].
This can only be done effectively, with proper communication. Understanding the
communication process and working on areas that need improvement, helps managers
become more effective communicators.
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The finest technique of finding the areas that requires improvement is to ask
themselves and others at regular intervals, how well they are doing. Such introspection leads
to better relationships and helps the managers in directing plans.
Control function includes establishing performance standards, which are aligned to the
company's objectives. It also involves evaluation and reporting of actual job performance.
When these points are studied by the management, it is necessary to compare both these
things. This study or comparison leads to further corrective and preventive actions. In an
effort to solve performance problems, management should set high standards. They should
clearly speak to the employee or department which has a problem. On the contrary, if there
are inadequate resources or other external factors, which prevent high standards from being
attained, management has to lower their standards as per requirement. The controlling
processes, in comparison with other three, are a continuous process. With this function,
management can anticipate any future problems. It helps them in taking necessary preventive
measures, against the consequences. Management can also recognize any further developing
problems that need corrective actions.
Effective and efficient management leads to success, which is the attainment of
objectives and goals that an organization sets for it. Of course, for achieving the ultimate goal,
management needs to work creatively in problem solving and execute all the four functions.
Management not only has to see goals accomplished, but also sees to it that the strategy
adopted is feasible for the company.
One of the manager‘s goals is to create teams that developing social interaction skill of
employees [5]. This social skill can be achieved through team building activities that provide
a venue for them to enjoy and learn at the same time. Planning for this type of activity would
require organizers to know much about the functions of management for them to be able to
facilitate it effectively. Other than creating a list of activities that employees can do, keeping
the theme in mind is always essential. Every team building organizer must ensure that
leadership and management are made the focal point of the activity because it helps develop
people skills to become goal oriented and well driven.
Like what has been initially mentioned, team building ideas must be rooted from the
main theme or objective of the entire activity. Keeping every single activity connected to the
others will help organizers and companies achieve what they actually came for. Although they
are having fun while performing the team building activities, they are also discovering
something new about themselves, about their co-workers or employees, and about their
company.
When thinking of the right team building themes and objectives for a group of attendees,
identifying their character as a group must be known, as well. Researching and learning about
their current issues will definitely help organizers in creating the actual activities that the
attendees can do. Team building activities must always apply to the experiences for it to
become memorable and helpful in their daily life. An example of this would be to develop
team building activities that would require individuals to go outdoors for athletic groups,
while the use brain teasers can be used to liven up a group of people who prefer mental
challenges.
As the main objective of the activity, the skill of portraying the roles of an effective
leader will emerge and will be noticeable the moment attendees leave the team building
facility. In planning for the activities for the corporate team building, one must ensure that the
end goal must always be achieved.
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A lot of planning and preparations must be done beforehand for the organizers to
achieve their main goal which is to promote growth and development in the attendees.
The main functions of the management cover a lot of facets which include production,
personnel, marketing, and many more. The different areas where the management sector is
inevitable differ from one industry to another. But what makes these different sectors become
similar is the need for the employees to portray leadership and good management skills. Here
are some possible team building activities and ideas that will achieve various goals and can be
used in different sorts of themes.
- Competitive activities
Companies that function through sales and production will definitely benefit the most from
competitive activities. Whether it would be through sports, games, or problem solving, this
type of team building activities will definitely bring out their competitive side and their
leadership styles.
- Individualized modules
It is always best to know oneself before one is able to improve on their skills. Individualized
modules for team building activities are those that enable attendees to answer handouts for
them to discover their own skills such as their style of leadership or their style of learning.
Activities that would allow them to look into their personal issues both in personal life,
career, and spiritual beliefs also belong with the individualized modules that can be used.
- Role playing activities
In every team building seminar, having a good time is always something that people look
forward to. The role playing can be utilized in team building activities because it allows
attendees to practice things that they can do to prepare them for real life situations.
There is nothing more gratifying than to see the results of one‘s hard work in preparing for the
team building activities. The easiest ways to learn about this would be the attitude of the
attendees because the activity can be said to be a success if they have a renewed energy to
work and be a participative part of the company. In addition, they also work positively
allowing them to produce great results and affirming ideas that help the overall growth of the
company through these team building activities if they are motivated, as we see in figure 1.
Internal
factors
External
factors
Individual
behavior
(motivated,
directed,
initiated,
continued)
Reward
(result)
Satisfaction
Fig.1. The behavior influence on the reward process
Any organization is comprised of people, and this staff needs direction. There must be
communication between department heads, plus motivation is required to get the various
teams headed in the right direction as set out in the planning stages. Prizes, incentives,
commissions, bonuses, even vacation packages can all be motivational tools utilized by
managers to effectively direct their employees and staff.
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A good manager understands the communication process, and thus knows how to
problem solve and build positive interpersonal relationships.
A final management concept is that of control. All the staff and workers of a company, at
whatever level of job-function, need to have a clear understanding of the performance
standards required of them. Obviously there will be higher standards required for those staff
in positions entailing higher levels of responsibility. Whichever the case management
concepts are almost always an ongoing and continuous operation, with the function of
maximizing company objectives and goals. The company is truly a series of relationships, and
ensuring the smooth flow of those relationships can be challenging at best. Efficient and
successful implementation of these management concepts will guarantee company success
3. CONCLUSIONS
The main purpose of this paper is to analyze the management relationships between manager
and his enterprise employees. Due to the large number of parameters and variables involved
in management problems, it was achieved many models through the time. At present,
researchers create new theories. As researchers and consultants write about their ideas and
experiences, they analyze what in business do and draw conclusions about why certain things
work. Unfortunately, business people often think that they do not have the time to reflect.
Business people need to reflect more on their practices and share their experiences, especially
those that did not create the expected results. To speed up the realization of the theories and
overcome the obstacles, business people responsible for the results need to be more active in
this process. There is no ―one size fits all‖ theory or practice. It is easy to talk about how to
create a workplace where people can fulfill their aspirations [6]. Without learning in the
context of practice very little can be accomplished. People can be sent to courses and be
engaged the best consultants and researchers, but it will not be enough. Business people need
to realize that while doing and learning will sometimes fail, and the best hope it has is to learn
from their mistakes by first admitting them.
REFERENCES
[1] Cornescu V., Mihãilescu I. Management. Editura Actami, 1997.
[2] McGregor D. The Human Side of Enterprise. McGraw-Hill Book Company, 1960.
[3] Mercioiu V., Bob C., Tomescu F. Management Comercial. Editura Economică, 1998.
[4] Shenkar O. Global Aspect of Human Resource Management. Boston: Irwin, 1995.
[5] Zorlenţan T., Burduş E. Managementul organizatiei. Editura Economică, 1998.
[6] Wilson Iva M, (Retired President, Philips Display Components-Philips North America).
REFLECTIONS, Volume 2, Number 1, Society for Organizational Learning, Massachusetts
Institute of Technology, 1996.
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THE SPECIAL CONSTRUCTION FACILITY AT INCD-INSEMEX FOR
TESTING EXPLOSIVES AND CHEMICAL FERTILIZERS WITH
DETONATION IN SAFE CONDITIONS
Phd. Eng. Attila KOVACS INCD-INSEMEX [email protected]
Eng. Daniela-Carmen RUS INCD-INSEMEX [email protected]
Eng. Edward- Jan GHEORGHIOSU INCD-INSEMEX [email protected]
Abstract: Tests on explosives for civil use and chemical fertilizers which are likely to have an explosive
behavior, involves special risks when the load is confined in steel tubes. The bunker was designed as a half
buried construction, with baffle, with the base plate of reinforced concrete and a steel plate in the blasting area
Keywords: confined explosive charges, safety, blasting facility.
1. General issues
Technical requirements for testing on site involve detonation of explosive charges in
accordance with harmonized European standards with the laws and regulations in force
require special equipment and facilities.
Tests on explosives for civil use and chemical fertilizers which are likely to have an
explosive behavior, involves special risks when the load is confined in steel tubes.
To avoid risk of injury due to shrapnel resulting from the detonation of explosive charge
confined in steel tubes, is necessary to take appropriate measures to protect staff.
To this purpose, in INCD-INSEMEX the explosives test area was made a proper
construction for that kind of tests in safe conditions.
This construction should meet a series of very severe requirements regarding the work
for which it was provided and the dynamic stresses on structural elements caused by the
explosion. Detonation of explosive charges in the confined environment (steel pipe) the
explosion generates a pressure that manifests dynamically on constructive elements of the
bunker and projects metal shrapnel at thousands of m / s, which due to kinetic energy and
very sharp cutting edges can damage the construction.
Given these two aspects had designed a technical solution which, on the one hand to
give adequate strength to dynamic manifestation of explosion pressure with its release to the
outside and on the other hand an inner plating designed to retain splinters resulting the
performed tests
Structure calculation had as primary elements the maximum amount of explosive
detonated instantly, predictable, for safe on inside retention of all the splinters, expansion of
explosion pressure, a reasonable time to remove fumes explosion in a dilution without a
mechanical ventilation.
2. Design, construction and maintenance
The maximum quantity of explosives planned to detonate was established to be 10 kg
TNT equivalent of considerations arising from the test procedures applied in the laboratory,
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both for civil use explosives detonated confined in steel pipe and for the test the detonability
of chemical fertilizers in accordance with European Regulation 2003/2003.
This maximum amount was the result of calculations that are necessary for testing of
chemical fertilizers on detonability with high ammonium nitrate content where the effective
approximate load in the steel tube is 8.5 kg fertilizer and it is applied a booster of 500 g for
initiation weight. The 10 kg TNT equivalent considered results from applying a safety factor
to compensate for the sudden increase of pressure on the walls and ceiling of the construction
and cumulative effects that lead to "fatigue of material " (steel concrete), after such repeated
dynamic loads.
Figure 1. General view of the blasting facility (bunker)
The bunker was designed as a half buried construction, with baffle, with the base plate
of reinforced concrete and a steel plate in the blasting area in accordance with the standard
SR EN 13631-11, and the walls should be provided with replaceable liners of hardwood.
The resistance structure of the bunker consists of reinforced concrete, with high density
of corrugated iron-Φ16 mm in brush and cast at once as a concrete structure piece.
Parameters for calculating the internal volume of 28 mc (3,15 x 3,15 x 2,8 m) to explode the
maximum amount provided for 10 kg TNT equivalent explosive generates a maximum
dynamic pressure varied according to certain structural elements of the location load (which
detonates on the floor).
Explosion pressure decreases exponentially with increasing the distance from the
structural elements, so the calculations revealed a maximum: at the ceiling 8 N/cm2, at the
walls 15 N/cm2 and at the floor 20 N / cm 2.
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Figure 2. Fumes resulted after a blasting operation in the bunker
If charges of explosives for civil use are detonated (e.g. Determination of velocity of
detonation) in the confined environment, the explosive charge is placed freely suspended near
to the geometric center of the room with the remark that of the charge will be smaller than the
10 kg TNT equivalent considered in the design.
Figure 3. Confined explosive charge placed in bunker – ready to blasting
Where the blasting scheme of chemical fertilizers for detonability test established in
European Regulation 2003/2003, the charge confined in the steel pipe inside Φ100 mm, is
placed on six lead cylinders with 100 mm height on a steel plate with thickness of 120 mm,
on the floor in the center of the room.
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Figure 4. Blasting scheme for the detonability test for chemical fertilizer in bunker
In this situation the pressure on the floor is considerably higher than that exerted on
the walls and ceilings. Protecting the reinforced concrete construction elements resulting
splinters after blasting charges was confined with half balls of wood on walls and ceiling and
a thick layer of sand 120/150mm.at the floor. Wooden balls were mounted to protect the
ceiling and walls are destroyed relatively quickly (3-5 shooting) with charges close to the
nominal, and the often replacement is necessary.
In order to reduce human labor consumption in refurbishing and maintenance
activities in 2011 was decided to replace the wooden ceiling plating with steel armor, 20mm
thick sheets, fixed on a metal frame made of rectangular sections of mining type track.
3. Conclusion
The structure is operational from 2006 fulfilling to the needs of the testing laboratory,
while behaving well, being made a considerable number of bastings in maximum safety
conditions, without damage to the structure of resistance.
4. References:
[1] Regulation (EC) nr.2003/2003 of the European Parliament and of the Council of 13
October 2003 relating to fertilizers.
[2] Recommendations on the TRANSPORT OF DANGEROUS GOODS. Manual of Tests and
Criteria. United Nations New York and Geneva, 2003.
[3] Rus, D.C., „Studiu privind situaţia pe plan mondial şi European a capacităţii tehnice de
efectuarea ciclurilor termice pentru realizarea testului de detonabilitate a îngrăşămintelor
chimice cu conţinut mare de azotat‖, INSEMEX Petroşani, 2010.
[4] Test Procedure ETI-PI-2.2 "Determination of the detonability of fertilizers based on
ammonium nitrate with high nitrogen content. INSEMEX Petroşani, 2010
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TECHNOLOGIES FOR BIOREMEDIATION OF SOILS
CONTAMINATED WITH PETROLEUM PRODUCTS
Lecturer PhD., Roxana Gabriela POPA, University Constantin Brâncuși of Tg-Jiu,
[email protected]
Associate Professor PhD, Maria CĂLINOIU, University Constantin Brâncuși of Tg-Jiu
Abstract: Biological methods for remediation of soils is based on the degradation of pollutants due to activity of
microorganisms (bacteria, fungi). Effectiveness of biological decontamination of soils depends on the following
factors: biodegradation of pollutants, type of microorganisms used, choice of oxidant and nutrient and subject to
clean up environmental characteristics. Ex situ techniques for bioremediation of soils polluted are: composting
(static / mechanical agitation), land farming and biopiles. Techniques in situ bioremediation of soils polluted
are: bioventingul, biospargingul and biostimulation – bioaugumentarea.
Key words: soils, polluted, technologies, bioremediation
1.Introduction
Biological methods for remediation of soils is based on the degradation of pollutants
due to activity of microorganisms (bacteria, fungi). Biodegradation is a natural phenomenon,
because the soil, subsoil and groundwater is normally living environment for many
microorganisms (bacteria Pseudomonas, Bacillus, Arthrobacter and Flovorbacterium and
fungi Trichoderma, Penicillium and Asperigillus), having an action on degraded organic
pollutants. This type of decontamination is suitable for petroleum hydrocarbons (diesel, light
fuel oil, gasoline, kerosene, mineral oils, benzene, toluene, xylene). Effectiveness of
biological decontamination of soils depends on the following factors:

biodegradation of pollutants - their ability to degrade under the action of
microorganisms.

type of microorganisms used - indigenous microflora of the polluted area may be
necessary decontamination of microorganisms, but microorganisms can also use
"specialized", which are developed on a mineral support (zeolites, carbonates,
composites) and mixed with the contaminated environment.

choice of oxidant and nutrient - oxygen administration in contaminated
environment, as air, pure oxygen, ozone, hydrogen peroxide and nitrogen trioxide,
following the introduction of oxygen and oxygen compounds in a reducing metal
oxidation conditions are created (cross-Fe2 + in Fe3 +) and hydroxide flocculation,
organic nutrients most commonly used processes biodecontaminare are methane,
propane, molasses, inert organic material (bark and straw) and surfactants.

subject to clean up environmental characteristics - pH, temperature, humidity,
physical parameters
2. Ex situ techniques for bioremediation of soils polluted

ex situ bioremediation = biodegradation in bulk = methods for solids used for the
remediation of contaminated soils on-site organic products, is the excavation of
polluted soil and its disposal in the vicinity of the excavation site, the technical
conditions that promote natural aerobic biodegradation
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
source of microorganisms derived from bacterial flora present in the soil

biodepoluare most important methods are:
2.1. Composting (static / mechanical agitation)

the oldest and simplest technique for biodegradation in bulk soil contaminated

contaminated soil is excavated and additive (mixed) with blowing agents (coarse
organic materials, straw, hay, bark scraps, manure), which fulfill a nutritional role and
encourage air circulation and water, essential to aerobic microbial metabolism

the resulting mixture is deposited on the soil surrounding the piles regularly, with a
circumference of several meters and a height of one meter

providing basic conditions accelerate the degradation process is aeration, moisture
and nutrient intake

composting = biotechnology requires thermophilic conditions (55-60 ° C),
favoring activities biodegradative

technologies are:
a.
static plie composting (piles are aerated by blowers or pumps)
b.
mechanically agitated in vessel composting (contaminated soil is placed in
machines which made mixing and aeration)
c.
windrow composting (placement in long mounds, mixed periodically with specific
eguipment
2.2. Land farming
 treatment of contaminated soil, the execution of specific agricultural work
 after excavation, soil pollution is deposited on a flat surface in a layer several
centimeters thick and treated with fertilizer or manure (fertilizer intake improves nutrient
balance - carbon source (pollution), and if manure increases the amount of
microorganisms available
 technique is farming land excavation, display on a platform that allows fluid drainage
collection, mixing and monitoring = technology for bioremediation of soil contaminated
by wetting, aeration, nutrients and blowing agents to promote aeration and circulation of
fluids in to increase the rate of microbial degradation of contaminants ( fig.1)
Fig. 1. Land farming technology for bioremediation of soils polluted
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2.3. Biopiles
 apply to clean up the soil with high content of volatile substances
 involves excavation of polluted soil and deposit it in the pile, and to prevent migration of
pollutants into the environment gaseous and liquid present in contaminated soil, entrances
and exits gas and liquid phases are controlled by the deposit of contaminated soil on a
slope and located impervious cover pile of soil contaminated with a membrane that retains
the gas in the enclosure biopic
 above the stack, as waterproof membrane is installed agricultural spraying device for
moistening the soil and nutrient management and micro-organisms around the stack, at its
base, is provided a gutter which is intended to collect liquid waste out of lot (because of
the sloping site, the effluent is recovered and pumped into a pool and administered by
sprinkling over the stack
 exploiting the "biopic" requires continuous monitoring and appropriate adjustment of
parameters: pH, temperature, humidity, pollutants contained in exhaust gases of the
atmosphere
 biopic = biotechnology derived from Land Farming method, based on increasing the
contaminated soil mounds several meters high, ensuring aeration and humidity + intake of
nutrients, contaminants are reduced to CO2 and H2O, within 3-6 months (fig. 2)
Fig. 2. Biopiles technology for bioremediation of soils polluted
3. Techniques in situ bioremediation of soils polluted
 biodegradation in situ = application biodecontaminare operations directly affected by
pollution in the environment (soil, subsoil, water table), without the need for
excavation of soil or water pump, is recommended for major extensions of pollution,
in depth and laterally, and and remediation of soil below the building
 principle is the introduction of the contaminated area of nutrients and oxygen, to create
favorable conditions for biodegradation of organic pollutants
 provides the classic underground water injection are dissolved phosphorus, nitrogen
and oxygen, which accelerates the annihilation reaction for aerobic pollutant, can be
applied to two distinct systems for in situ biodegradation: the passive and active
system
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a. Passive system - means taking the solution with nutrients and oxygen spray, over the
contaminated area and injection wells or wells, installed upstream of the contaminated
area, if the pollutant floating on the groundwater table, taking nutritional solution is by
spraying, for this pollutant solution to quickly reach and contact with it to make the
greatest possible surface (fig.3)
b. Active system - is based on management solution with nutrients and oxygen through
wells or wells located upstream of the air, is provided in addition to drilling wells and
pumping water downstream of the contaminated area (fig. 4.); system is based on
recirculated water before being reinjected the soil is decontaminated in a specialized
unit, use the active system allows for in situ biodegradation of remediation yields better
than when applying the passive system, the positive effects of the active system due
convection is the movement of contaminated ground water, leading to a pronounced
stimulation of biodegradation of pollutants
Fig. 3. Passive system layout
Fig. 4. Active system scheme
3.1. Bioventingul
 forced aeration is contaminated environment to stimulate mobilization of volatile
pollutants and degradation processes based on biomass development in the basement
 rebalancing report carbon - nitrogen - phosphorus in contaminated environment is
achieved by adequate intake of nutrients in water dosed and administered by
sprinkling the ground or through injection wells applied upstream of the contaminated
 vacuum extraction is volatile pollutants by creating a current of air that favor
biodegradation; recover gas from the underground is possible with a drain located near
the surface and connected to a ventilator
 is a biotechnology based on the stimulation of degradation of contaminants in the soil,
by injection of atmospheric air and nutrients (nitrogen, phosphorus) is for in situ
decontamination of POLs (petroleum, oils, lubricants)
 factors that limit the application of this technology are: poor soil aeration, soil water
saturation, low percentages of nutrients (nitrogen and phosphorus), reduced aerobic
biodegradation by cometabolism or anaerobic, low temperature (fig.5)
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Fig. 5. Application technology bioventing site the remediation of soil
3.2. Biospargingul
 air injection is performed in air, using a network of special drills, air pollutants
vaporize injected dissolved or retained by the capillary pores, mobilizing them to the
surface, on their way upward, finely dispersed pollutants are degraded by biomass
stimulated by aeration and nutrient intake
 in fig.6 is played biosparging principle method for simultaneous remediation of
unsaturated zone and saturated zone
Fig. 6. Application technology biosparging site the remediation of soil
 bioremediation of soils can be achieved by injection of hydrogen peroxide in sites with
petroleum hydrocarbon pollution constant, volatile organic compounds, halogenated
compounds, metal ions
 effects are: stimulating existing microbiota, increasing the speed of bioremediation by
soil water movement, aerobic metabolism of pollutants, their declorurarea, in situ
immobilization of metals dissolved by the intake of O2
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Fig. 7. Soil remediation technology injection of hydrogen peroxide
3.3. Biostimulation and bioaugumentarea
 biotechnology is a growth rate of biodegradation of soil contaminated with nutrients
and oxygen dissolved in water for injection
 microbial activity is stimulated by movement of water, supplemented with inoculum
(aerobic or anaerobic process) (fig.8)
Fig. 8. Technology biostimulation and bioaugumentare polluted soil
4. References
[1] Alexander M., Biodegradation and bioremediation, Academic Press, San Diego, 1994
[2] Cookson J.T., Bioremediation Engineering: Design and Application, McGraw-Hill, New
York, 1994
[3] Malschi D., Integrated pest management in relation to environmental sustainability. Part
I. Ecological management of wheat pests, Bioflux Publishing House, Cluj-Napoca, 2009
[4] Bruce E.Pivetz, Phytoremediation of Contaminated Soil and Ground Water at Hazardous
Waste Sites, Edited by United States Environmental Protection; Agency Office of Solid Waste
and Emergency Response; Office of Research and Development, 2001
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ASPECTS REGARDING THE DESIGN AND PERFORMANCE OF
FLAMEPROOF ELECTRIC MOTORS SUPPLIED VIA STATIC
FREQUENCY CONVERTERS FOR EXPLOSIVE ATMOSPHERES.
DR.ING.Mihai MAGYARI INCD - INSEMEX [email protected]
DR. ING. Sorin BURIAN INCD – INSEMEX [email protected]
DR.ING.Martin FRIEDMANN INCD-INSEMEX [email protected]
DR.ING.Lucian MOLDOVAN INCD – INSEMEX [email protected]
Abstract: The electric power drive systems consisting of three phase induction motor and static frequency
converter are designed to enhance the performance on site, by diminishing the energy consumption, optimization
of the technological processes and the reduction of costs for the maintenance and repairs of the equipment.
The paper presents some important issues concerning the selection of inverter fed flameproof electric drives in
the field of potentially explosive atmospheres of gases and vapors by ensuring a correct risk management
against the hazard of electric sparks as well as excessive temperatures.
Key-words: flameproof, electric power drive, frequency converter.
1. Fields of use for variable speed electrical motors.
Equipment consisting of rotor cage three phase asynchronous electric motor supplied
by a static frequency converter are designed to enhance the performances in exploitation, in
the sense of reducing the energetic consumption, optimization of the technological processes,
enhancing the reliability and safety in operation, simplification of the installation and
reducing of the costs for the maintenance and repair of the overall equipment.
The three phase electric motor supplied via a frequency converter is being used in all
types of power drives systems in which the speed variation ensures the regulating of
parameters such as pressure, speed or flow.
On the other hand, alternative current variable speed drives using the assembly made
up of electric motor – static frequency converter can easily replace the continuous current
motor drives.
By using variable speed drives, an important economy potential is being created. In
industrial power drives we can distinguish two groups of equipment:
a. a group in which the technological process requires the electric motor to have an
electronic command speed adjustment;
b. a second group that includes: pumps, fans, mills, etc.
which function without speed regulation, but in the case of which a great amount of energy is
being lost due to the use of valves, faucets or other systems for the regulation of process
parameters. By using variable speed drives one can obtain an economy of 20 to 70% of the
total energy consumption.
In a variable speed drive, the rotor cage electric motor can be started slowly, with a
small current and the speed can be controlled and adapted continuously, on a large scale, to
the process demands.
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2. Specific requirements imposed by the functioning of electric motors supplied
by static frequency converters in explosive atmospheres.
2.1 Constructive features.
All electric motors used in potentially explosive atmospheres have to be ATEX
certified, according to the standards for the specific type (s) of protection to which they have
been designed.
According to the regulations, the electric motor has to be so designed that the
maximum surface temperature of the enclosure of the motor is limited according to the
temperature class of the application of gases or vapors in which it will be used (this is
typically temperature class T4 or T3). This requires certain tests to be run, in order to check
and measure the external temperature of the motor.
The vast majority of electric motors falling in the T4 temperature class are being
tested by supplying via a static frequency converter using a loading characteristic according to
Figure 1.
Fig.1 Loading characteristic
2.2. Winding insulation
The winding insulation system of the motor, in case of supplying via a static
frequency converter is submitted to higher dielectric stresses than in the case of supplying
with sinusoidal currents and voltages. In the case of supplying via a current source converter,
during the commuting phase, voltage peaks are likely to occur in the motor, which induce
stresses in the winding insulation system.
The dielectric stress of the winding insulation is determined by the peak voltage, the
rising time and the frequency of the impulses produced by the converter, as well as the
characteristics and the length of the connection between the converter and the motor, and
other parameters of the system.
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The combination between rapidly commuting converters and cables is likely to
produce voltage peaks due to the effects of the transmission line. In the case of motors having
a rated voltage less or equal to 500 V a.c. the insulation system has to be so designed as to
cope with the maximum peak voltages to which it will be faced.
In the case of motors with rated voltage of more than 500 V a.c. and up to 690 V a.c.,
supplied via rapidly commuting converters, it may be necessary to apply an enhanced
insulation system and / or filters designed so as to reduce the rising time and / or the peak
voltages.
The voltage field ∆u is the difference between the instantaneous values of the voltage
right before and after the voltage impulse. This impulse ends right after the voltage reaches its
first maxim. The rising time ta is defined as the time interval in which the voltage varies
between 10% and 90% of its overall field ∆u.
Due to the complex inter conditionings, it is necessary to have a careful design of the
entire electric power drive. This requires sometimes the use of filters at the output of the
converter.
2.3. Thermal protection of the insulation
The temperature control for electric motors supplied via a static frequency converter is
usually made with the help of thermistors with positive temperature coefficient – PTC code,
which are inserted in the winding of the motor. With the help of these thermistors which are
connected via the terminal box of the motor to the protective device of the static converter, the
motor can be disconnected from the electric power supply in case of abnormal operation or
due to the overload conditions, by this avoiding the exceeding of the temperature above the
maximum admitted limits.
According to the ATEX Directive, with reference to Power Drive Systems (PDS), the
concept of power drive system is used to describe a variable speed electric drive of an electric
motor as an integral part of an assembly consisting of electric motor – static frequency
converter.
The schematic representation of this system is shown in Figure 2.
Figure 2 The Power Drive System
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Where:
 BDM – Basic drive module consisting of power input, control and power output
selections;
 CDM – Complete drive module consisting of BDM and auxiliary sections, but
excluding the motor and motor – coupled sensors.
 PDS – Power Drive System, comprising CDM, motor and sensors.
According to this reglementation, the entire system comprising the electric motor and
the frequency converter, used in potentially explosive atmospheres of gases and vapors have
to ATEx certified. The motors are tested when supplied by the converter and the temperature
of the motor is determined using a specialized software in order to predict the temperature
evolution and to revent the overheating of the motor.
2.4. Bearing currents and methods of prevention
The most important factors that define whic mecansim is prominent are the size of the
motor and how the motor frame and shaft are grounded. The electrical installation, meaning a
suitable cable type and proper bonding of the earthing conductors and the electrical shield,
also plays an important role, as well as the rated converter input voltage and the rate of rise of
the converter output voltage. The source of bearing currents is te voltage across te bearing.
In all variable speed applications, in order to ensure the reliability and the safety of the
application, voltage and currents in the bearings have to avoided by all means. In order to
supply the motor with as much as posible sinisoidal currents, the output voltage of the
frequency converter must have a high chopper frequency.
The voltage peaks rapidly choppered of the output voltage of the converter high
capacitive currents and voltages on the internal capacitances of the motor. This capacitive
voltage induced in the bearing, can produce, in the worst case scenario, pinches in the
lubricant film of the rolling elements bearing, this leading to a premature wear of the bearing.
During operation of the converter, parasit currents through the bearings can be caused
by two kinds of voltages:
- The shaft voltage
The term shaft voltage applies to the voltage that is induced in the conducting ringlet
made of: shaft, bearings, endshields and enclosure, by a ring type flow in the stator.
The irregualrities in the stator (like the ventilation channels, etc.)can cause ring type
flow.
The ring type flow can be amplified by a continuous component of the stator currents
(the so called common mode currents), whose amplitude depends on the earth bonding system
of the motor.
A current peak occuras each time one of the semiconductor elements commutes,
generally 6 times during the impulse frequency period.
- The bearings voltage
The term bearing voltage applies to a capacitive coupling voltage at the radial ... of the
bearings.
The voltage in the bearings is caused by an alternative voltage between the average
potential of the stator winding and the grounded stator core (the so called common mode
voltage) which is inherent in the commnad and contro algoritm of PWM converters.
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The common mode voltage consists in particular of the components having the
frequency 3 times higher than theh frequency of the system, 3 times the basis frequency at the
output terminals of the converter and the frequency of the impulses.
The two types of bearing currents, high-frequency circulating current (IC) and shaft
earthing current (IS), are shown schematically in Figure 3. These are strongly influenced by
the earthing arrangements and earthing impedances.
Figure 3 Possible bearing currents
The experience has shown that:
- Motors framesize up to 315 inclusive, seldom experience deficiencies related to the
bearings in case of supplying via frequency converters.
In the same time, the dielectrical stresses in the bearings show variations in large
limits, function of the command algoritm of the converter.
When converters having an impulse frequency higher than 10 kHz are used, and an
output voltage higher than 400 V, it is recommended to use the insulation of the bearings.
- In the case of motors framesize higher than 315, the folloeing are recommended:
- the use of a filter type converter designed to reduce the continuous
component of
the phase voltage (the so called common mode
voltage);
- or to reduce du / dt of the voltage;
- to insulate the bearing of the motor;
- The insulation of a rollimg element bearing can be achieved by replacement
with an insulated bearing of the the same type and dimension. The insulation
of both bearings is rarely required.
2.5.Supply cables and the distance motor – converter
When determining the cross section of the cable and the distance between the motor
and the converter, several parameters have to be taken into account, such as the current value,
the connection conductor of the given motor, the maximum diameter of the sealing gasket of
the cable gland entry of the motor, as well as the drop of voltage across the cable which can
affect the parameters of the motor and the correct operation of it.
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By using frequency converters, it is possible to compensate the voltage drop across the
supply conductors of motors which are located at great distances from the converter.
2.6. Frequency / speed variation field and maximum safety speed in operation.
Function of the design of the motor, operation at higher speeds can be allowed, but
this possibility has to checked by appropriate testing.
In the case of operation at speeds higher than the rated speed, the noise levels and the
vibrations increase. It may be necessary to re balance the rotor in order to operate at speeds
higher than the rated speed.
Long term operation at speeds close to the maximum safety operation speed can lead
to a considerable life shortening of the bearings.
This may also affect the sealing of the shaft and / or the lubrication time intervals of
the bearings.
3. Conclusions
The electric motor supplied via a frequency converter is used in all driving systems
where by the speed variation of the motor, parameters like pressure, speed or flows are
regulated.
Also, variable speed drives of the type electric a.c. motor – static frequency converter
can easily replace continuous current motors power drives.
The paper helps to identify the advantages offered by the variable speed power drives
in potentially explosive atmospheres as well as it provides important information concerning
the appropriate selection of power drives consisting of an Ex motor supplied via a frequency
converter in applications in the field of explosive atmospheres of gases and vapors, by
ensuring a correct management of the ignition risk from electric sparks and excessive
temperatures.
The correct application of these issues will lead to a reduction of the costs and time
intervals necessary for the ATEX certification of such electric power drive systems designed
for explosive atmospheres.
References
[1] Directive 94/9/EC of the European Parliament and the Council of 23 March 1994.
[2] SR EN 60079-1:2004, Atmosfere explozive. Partea 1: Echipamente protejate prin carcase
antideflagrante „d‖, ASRO - Asociaţia de Standardizare din România.
[3] SR CEI 60034 – 17 Masini electrice rotative. Partea 17: Motoare asincrone cu rotor in
colivie alimentate prin convertizoare. Ghid de aplicare.
[4] IEC TS 60034 – 25 Rotating electrical machines. Part 25: Guidance for the design and
performance of a.c. motors specifically designed for converter supply.
[5] CEMEP European Directives – Application of the ATEX Directives to Power Drive
Systems.
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RELIABILITY,COMPONENT OF INDUSTRIAL
PRODUCTION QUALITY
Ph.D.Lecturer Monica BALDEA,Faculty of Mechanics and Technology,University of
Pitesti,e-mail:[email protected]
Abstract:The reliability defined through probability, reflects the measurement of the product's quality
depending on time. We use the probability parameters as aleatory variables, the density functions of probability,
the distribution functions.
Keywords: reliability, probability, variable
1. Using the mathematical instrument of the reliability.
The general, accepted definition of the reliability is that probability viewed as a
device ready to fulfil its specific functions without faults in a certain period of time, within a
framework of operating terms before hand specified.
From this definition we may deduce that reliability differs in point of meaning from the
notion of output quality control, i.e. through control we measure quality in point zero of the
product's life-span while reliability reflects the measurement of product's quality during time.
Reliability is quality control plus time.
As reliability is defined though probability the reliability theory has on its basis the
usage of probability parameters like aleatory variables, the functions of probability density
and distribution
distribution function. The faults distribution U(t) is defined as being the probability of
an aleatory variable be no bigger than t or at an aleatory test:
or
(1)
where: u(t) stands for density function of probability for aleatory de faults (time up to
incoming faults)
This is the non-reliability function, as we speak of the fault's appearance and may be
interpreted as being the probability of a fault emerging before a moment t.
If the aleatory variable is discrete, the sign of integral is replaced by sum.
The reliability function or the probability of a device not to break down before the
moment t, is:
R(t)=l-U(t)=
(2)
The probability of faultiness in a period of time [t1,t2] is expressed by the reliability
function:
u(t)dt=
dt = R(t 1 ) – R(t 2 )
(3)
The frequency of faults emerging in the period of time [t1,t2 ]or the fault quota Φ(t) is
defined as a ratio between the probability of the fault being produced it that time, on condition
of not being produced before t1 and the duration of time [t1,t2]
(4)
The momentary rate of the faults Z(t) is defined as a limit to the fault density when the
interval extends to zero.
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(5)
Specific functions of density and distribution commonly used are: normal function
(Gauss), exponenţial function, gamma function, Weibull function, Rectangular function.
If the product is realised by n reference points, and the faultiness of whatever leads to
the product' faultiness, then the product's reliability function will become:
(6)
where Ri(t) represents the reliability function of reference point i.
2. Reliability prediction and analysis .
Predicting reliability is the process by which we estimate numerically the capacity of a
product to fulfil its function requested without faults. The measures used by this are: R(t) –
probability of surviving without fault after a period of time; average life span or its apposite
the faultiness quota λ in case we cannot replace the faulty components: average period of time
for good running when we are replacing faulty components.
In predicting the faults it's necessary to anticipate the frequency various faults may
manifest. Thus, the most dangerous are the faults produced when certain reference points of
the product become inactive, coming up as a spontaneous damage without any preliminary
symptoms.
Another sort of faults is represented by those caused due the incompatibility between
tolerance limits of product and the reference point.
The most practical predictive method supposes: defining the product and its
manifestation that will be considered faulty: drawing the block chart of reliability, drawing up
the list of each block components; selecting the data concerning reliability of the components.
Establishing the adequate faults of distribution for every component: establishing the
adequate reliability factor through its function R(t), establishing the distribution of faulty
systems due to their faulty components.
3.Designing reliability .
As the reliability prediction corresponds to the case when we know the number and type
of basic components forming the product, the designer is given only the reliability conditions
requested by the product.
The first stage in designing is distribution of reliabilities restrictions of the whole
product among its main reference points. Then follows, the process of establishing the
average range of faulty components for every principal reference point.
The results obtained are compared to the existing data about average range of faultiness
to verify whether the requested terms are being accomplished with the elements taken into
view. Otherwise, to reach the wanted reliability the designer has to use one of the following
methods:
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- finding better components as for reliability
- simplifying the project to use less components and not to disturb the operating
performances of the equipment:
- applying methods of increasing the components' reliability
- using redundancies whenever necessary
In the reliability technique, redundancy may be defined as the existence of several
means to realise a certain characteristic. Generally speaking, all those means have to go
wrong so that the system becomes faulty.
If we assume a simple system made up of two elements in parallel with A1, having a
faultiness probability p1 and A2, having a probability p2, then the possibility of the whole
system be disrupted will be calculated according to the formula:
P = p1·p2
(7)
And the reliability or probability of not displaying any faults is R calculated as follows:
R = 1-P=1- p1·p2
(8)
Consequently the redundancy in parallel, is a solution to increase the system's reliability in
case other methods cannot be applied. Generally speaking if there are in parallel components,
the probability of the whole system become faulty at t (time) is P(t) calculated accordingly:
P(t)=p1(t)·p2(t)…pm(t)
(9)
And the probability of non - faulty working is given by formula:
In the components reliabilities equal then:
P(t) = p(t)m
R(t) = 1 - p(t)m
(10)
(11)
It's quite impossible for two elements made within the output according to the same
specifications be similar. The variability of the components' characteristics leads also to the
system's variability consisting of those elements. The designer may check the implications of
this variability if he has got enough information about specific variations of the components'
characteristics either at their first usage or according to the time and request. If these aren't
taken into consideration in running the respective system, we'll get to a worsening reliability
due
the
uncontrolled
influence
of
these
parameters
4. Testing reliability.
To measure reliability, statistical data are being and processed product' related to the
product service performance within the requested interval of time. This can be done by
observing a certain number of products under service, measuring the intervals when these
didn‘t go wrong and the number of flaws, which appear during observation period. After we
got sufficient data about the moments of faultiness we can quite accurately estimate the
average running time without flaws.
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The issue of treating reliability is more complicated where there are very little
information or they merely don‘t exist, about the formula of time faultiness distribution
specific the reference points or the products on the whole. In this case we use a sample on
which basis we estimate the form of distribution and its parameters.
The testing reliability essentially consist of establishing the distribution of a statistical
data parameter and estimation of the parameter.
Establishing the confidence according to which we can admit that from the analysis of
the respective sample, it results that the effective value of the parameter is situated within the
limits of the concrete interval. Finding the answer to the question whether each reference
point of the product has a certain average life span and establishing the measure which
guarantees us these will be confirmed during services. Substantiation of the sample's size and
of time consumption for the necessary attempts. For the testing reliability, we separately
analyse the situation of aleator, faultiness at complex products, the situation of confidence
limits of aleatory defaults, the evolution in time of these ones according to Weibull
distribution and the achievement sequential test of reliability.
5. Conclusions
The variability of the components characteristic produced during the output leads also
to the variability of the system's characteristics consisting of those elements.
The designer may examine the implications of this variability if he's got sufficient
information about specific variations of the components' characteristics either at their first
usage or according to the time and request.
References
[1] Glueck F.W, Strategic management for competitive advantage , In: Harvard business
review, 1980
[2] Naisbitt J, Megatrends,In: New York Warner, 1984
[3]Dirna I.C, Management of industrial output Bucharest, Didactica si Pedagogica
Publishing House, 1999
[4]Bacanu B,Strategic management, Teora Publishing House, Bucharest, 1997
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CONDITION ASSESSMENT OF SUBJECTIVE COMFORT AND THE
REACTIONS OF THE POPULATION IN THE URBAN CONTEXT OF
EXPOSURE TO NOISE
PhD. NICA-BADEA Delia, Constantin Brancusi University, Faculty of Medical and
Behavioral Sciences of Targu-Jiu, Romania, [email protected]
PhD. PASARE Minodora Maria, Constantin Brancusi University, Faculty of Engineering
Targu-Jiu, Romania,
Abstract:The paper considers this issue matters as of interference noise of the ordinary activity of the population owing
to its cause and its presence in all departments of life. Noise pollution is a major problem in all countries where we are
witnessing a phenomenon of magnification levels of noise having effects more or less aggressive about comfort and
even health. Are presented arguments relating to the characterization of noise as a risk factor in the induction of
pathologies such as: auditory disorders, hypertension, ischemic heart disease aggravation, discomfort, sleep disorders
and decreasing school performance in children. For the evaluation and management of ambient noise has developed a
study aimed at assessing the state of comfort and subjective reactions of residents in order to fundamentarii measures
for reducing the levels of exposure and prevention of the effects of population exposed to noise in the street. In areas
with heavy traffic confirm the existence of risk perception of 56% of the people who accuse the discomfort caused by
noise in homes during the day and during the night rate is 40%. The age groups most affected are 51-65 years and over
65 years old, because they spend most of the time period in the home.
Keyword: noise, exposure, assessment risk
Introduction
In view of the fact that noise is one of the most important factors for the most part,
human-discomfort should be knowing his action on the body. Annoyance caused by noise
pollution has been mentioned in the course of human history : Quintus Horatius Flaccus (65-8
î.e.n.), Decimus Junius Juvenalis-60-140 e.n..), Paracelsus in the 16th century and the 18th
century Ramazzini, which refers exclusively to the noise of productive activities. In the 20th
century the first systematic studies appear on urban noise, though long before, it was referred
to as disruptive activity ordinary population. Under the conditions of modern civilization due
to its harmful nature and its presence in all the bins, noise pollution is a major problem in all
countries where we are witnessing a phenomenon of magnification levels of noise having
effects more or less aggressive about comfort and even health. Psihofiziologicals indicators
calculated index bother and TNI (Traffic Noise Index) marks and such a parallel evolution,
from the moderate values of noise, a decade ago, very noisy and even traumatic for the past
few years, acknowledging the possibility of pathological processes start up for people
exposed. He becomes a public health problem in Europe with mechanization, urbanization
and increasing urban population density. [1, 2, 3, 4]. European policy with regard to noise, the
vision for the year 2020, aiming for, that no one should be exposed to levels of noise which
put in danger the health or quality of life. Are sufficient studies that have shown that exposure
to noise can cause hearing disorders: aggravation of ischemic heart disease, hypertension,
discomfort, sleep disorders and decreasing school performance in children. Recent studies
have shown that more than 20% of the world population lives in conditions of a sound level
which is unacceptable and over 60% of the population of Europe is exposed to worrying
levels of noise during the day [5]. Exposure to noise is increasing especially in living
environment, but also in industrial areas.
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Standards and legislation in the field of ambient noise limits its exposure to the
pollutant by indicating the limit values for pressure level equivalent continuous A-weighted,
LAeq. In Romania, the maximum limit is admitted in 35 dB (A) day and 25 DB(a) at night,
and condition of a sound external not exceeding 50 dB (A) and 40 DB(a) at night to 3 m
building.
2. The characterization of noise as a risk factor
Noise is an unwanted pest complex sound (has no informational content), which
depends on the particular conditions of work and life leading to mental and physiological
[6]States that are harmful to people exposed. In terms of propagation and noise perception by
humans is characterized mainly by three physical sizes, namely: the frequency which is
perceived as a physiological parameter, or the intensity of the sound pressure, sound
propagation speed is based on the average. As regards noise harmfulness (agent) is a physical
process that may constitute a danger to the health of employees, in conditions determined by
the allowable limits [7]. Effects of noise can be the following: dysfunction communication
work
by
masking
effect
of
words
(acoustic
communication
signals);
psihosenzorialdysfunctions (psychological and physiological) such as auditory fatigue,
deafness. Noise is admitted on the basis of equal intensity curves drawn in Cz audibly 31.5 Hz
to 8000 Hz (in eight octave frequency ranges). Depending on the duration and intensity of
exposure that is observed in Figure 1. are given different values, exceeding the length of
exposure lead to disorders of listening
Fig. 1. Representation of the harmful effects of noise depending on the intensity and duration of exposure.
Noise is inherent to hearing fatigue that contains the treble that leads to the lifting of
temporary auditory threshold of perception. This leads to reduction of hearing, the decrease in
attention and concentration of specific to the workplace. Also increases mental instability and
nervozitatea. Auditory changes are temporary and reversible. Hearing of the trauma occurs
when the sound pressure increases by large amounts in short time intervals, when the signal
variability is characterized by high speeds. The immediate effect consists in the appearance of
excessive pain, of the internal ear, with the possibility of deafness[8].
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Hearing loss is the most serious form of auditory organ damage caused by high
frequencies and intensities of about 100 dB in a period of prolonged exposure at frequencies
up to about 4000 Hz and then progresses and lower frequencies. The importance of the risk of
damage to hearing is given in Figure 2. The curve I of the lower values of permissible sound
ambience Are marks for quality work with appropriate strength. Area between curves I and II
corresponds to a noisy ambiance but not dangerous. Area between curves II and III
correspond to the risk of exposure to hearing deficit by 1/2 hour a day increases risk of 25%
on the II. The area between the curves of the III and IV lead to risks of auditory deficit by 5080%. IV curve and cause over surdităţii professional even in case of accidental exposures.
Figure 2. The risk of hearing damage after Wisner and Javille.
Overcoming vibration intensities of the intensity and duration of exposure, disturb the
physiological and organic psihosenzorial [9]. Vibration is characterized by frequency,
amplitude and acceleration. The relationship between amplitude and frequency effects of
human perception has led to the contours of the figure 3. The extended action of vibration on
humans lead to events by nausea, headache, vomiting, lack of appetite suppressants, changes
of pulse vibration disease, 30-250 Hz.Harmful vibrations are classified based on amplitude
and frequency as follows: the vibration frequency at more than 15 Hz and amplitudes up to
0,02 mm has a decisive influence and speed vibration; vibration amplitudes and frequencies
with small. Perception of the vibration frequency result after using the following
classifications:a) the vibration under 15 Hz specific vehicles, automobiles 1.5 ÷ 2 Hz, trucks 4
Hz ÷ 2, train 3-8 Hz. Prolonged exposure may cause pain paravertebrale, disorders of the
digestive and urinary tract; b) vibration frequencies ranging between 15 and 40 Hz with large
amplitudes (hammers of broken equipment incărcare-download). Specific injuries are either
articulary, tendons, muscle; c) vibration frequencies ranging between 40 ÷ 300 Hz, mining
equipment, steel and metallurgical processes. Burns sensations appear to decrease the
sensitivity of limbs, fingers. d) frequency vibration over 300 Hz, at some specific tools such
as machines to milling, grinding, lapping. Trophic disorders may appear and sensitivity of the
hands.
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Fig.3. Effects of perception
3. The ambient noise in relation with the state of comfort and health.
The ambient noise, as defined by HG. No. 321/2005, amended and supplemented by
HG. No. 674/2007, annex 1, article 20. as "all unwanted sounds, including damaging,
resulting from human activities, including those caused by means of transport, road traffic,
rail and from the location where they are held industrial activities" , represents a factor of
environmental quality monitoring. For the evaluation and management of ambient noise has
developed a study aimed at assessing the state of comfort and subjective reactions of residents
for reducing the levels of exposure and prevention of effects in the exposed population [10].
The study was carried out in 7 cities with a population greater than 250,000 inhabitants, on
main roads with traffic more than 6.000.000 vehicle passages per year, major railroad with a
traffic of more than 60,000 train passages per year and major airports. It has developed a
standardised questionnaire that sound subjective perception of the population watched the
homes located in zonelele the most boisterous of localities according to "strategic" map by
noise. The study was conducted on a sample of 350 housing units type apartment block and
individual houses, and tenants with different age groups: 20-35 years, 36-50, 51-65 years and
over 65 years old. The method used shall be that of self-administration by completing the
questionnaires printed documents. In every town there were a number of completed
questionnaires, 25 housing oriented to heavy traffic and questionnaires to residential area 25
(witness).
The results of this study highlight oserie aspects of well-being and body reaction
towards the street noise by day and night.Noise isolation provided by the construction
materials has a great importance in achieving the body condition of comfort needed, both for
the daily activities of unfolding as well as during your stay and sleep. Noise isolation differs
depending on construction materials, but also of diatanta of building and road network and
traffic intensity in the area.During the night the bother is low compared with very little day.
Rail traffic compared with road traffic is met with a frequency much smaller. The bother
appears air traffic with a frequency of 4% in cities like: Bucharest, Brasov, Iasi, Craiova
during the day and night is met only in Bucharest with the same frequency by 4%. Insufficient
car covered parking and location close to housing, but mostly by parking in organised sites,
create discomfort both day and night. The bother produced by intercity cars has a low
frequency and the east during the night there.
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3.1. The noise of their ailments is a risk factor.
Their ailments aggravated by noise in areas with heavy traffic are given in Figure 4.
Nevroze, the largest percentage of 64% reported out of the city of Brasov, in percentage at
24%, and 17% of all attractions in Bucharest. Aggravation of cardiovascular disease occurs
with a frequency of 52% to 32% in Brasov, Constanta and Galati in major cities, 22% in
Bucharest. Turmoil with a frequency of hearing less than 12% in Ploiesti, psychic diseases
with a frequency of 4% in Bucharest, Iasi, Ploiesti. Endocrine diseases with a frequency of
12% and 8% in Ploiesti, Iasi, and Craiova. Frequency for noise caused in the residential area
is much lower. With the highest frequency is 32% maintain cardiovascular diseases due to the
Constanța. Nevrozele owning a frequency of 12% in Iasi, Galati and endocrine diseases and a
frequency of 4% in Brasov, Galati and Ploiesti. Activities undisturbed by noise appear with
the highest frequency in groups of 36-50 years of age, followed by the age group of 18 to 35
years due to heavy traffic and noise isolation of inefficient building. Discomfort is felt during
leisure time, as well as reading and learning (Fig. 5). In the area with heavy traffic,
advertising noise as a factor of stress with the highest frequency of 58 percent, the same
percentage charged twitter moods,followed by state of fatigue, with a frequency appears with
49% ( Fig. 6).
Fig. 4. Ailments aggravated by noise in areas with heavy traffic
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Fig. 5. Activities undisturbed by noise
Fig. 6. Frequency of symptoms arising from noise in areas with heavy traffic
Conclusions
Ambient noise is defined as "all the unwanted sounds, including damaging, resulting
from human activities, including those caused by means of transport, road traffic, rail and
from the location where they are held activitatiile industrial" represents a factor of
environmental quality monitoring. As regards noise harmfulness (agent) is a physical process
which may be dangerous to health, in the conditions determined by the allowable
limits.Exposure to noise can cause hearing disorders: aggravation of ischemic heart disease,
hypertension, discomfort, sleep disorders and decreasing school performance in children.
Activities undisturbed by noise appear with the highest frequency in groups of 36-50 years of
age, followed by the age group of 18 to 35 years due to heavy traffic and the introduction of
the building noise isolation.
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Discomfort is felt during leisure time, as well as reading and learning. In the area with
heavy traffic, advertising noise as a factor of stress with the highest frequency of 58 percent,
the same percentage charged stari Twitter followed by State of fatigue, with a frequency
appears with 49%.Noise is an important factor therefore, monitoring of noise and health
impact assessment represents an essential component of the activity prophylactic.
References
[1]. Berglund B. - Noise as a public health problem. Proceedings of the 5th International
Congress on Noise as a Public Health Problem Stockholm, Epidemiology: January 2005–
Vol. 16 - Issue 1 - pp 33-40, Sweden.
[2]. Directiva 2002/49/CE privind evaluarea riscului şi managementul zgomotului ambiental,
Articolul 3, litera a).
[3]. Hotărîrea de Guvern 321/2005, Evaluarea şi gestionarea zgomotului ambiental, Nr 1,
def.20
[4].Passchier-Vermeer W., Passchier WF., Noise exposure and Public Health.
Environmental Health Perspectives, 2000; March; 108 (Suppl 1): pp 123–131.
[5] .Rivas S., Hernandz, R., Cueto, J. L. Evaluation and prediction of noise pollution
levels in urban areas of Cdiz (Spain), Acoustical Society of America Journal, 2003, vol. 114,
Issue 4, pp. 2439-2439
[6].Anghelache,G-D. Cercetări privind protecţia omuluila zgomote şi vibraţii in domeniul
tehnologiilor mecanizate pentru construcţii.Th D.,Brăila 2009
[7]. Bratu P. Note de curs la programul de master – Norme privind nivelurile de zgomot şi
vibraţii admise. Universitatea Politehnica Bucureşti 2003
[8]. *** ISO 3743: Acoustics - Determination of sound power levels of noise sources using
sound pressure- Engineering methods for small, movable sources în reverberant fields - Part
1: Comparison method for hard-walled test rooms; Part 2: methods for special reverberation
testrooms.
[9].Bratu, P. , Mihalcea A., Condiţii de securitate privind nivelul de zgomot şi vibraţii în
vederea atestării tehnice a maşinilor de construcţii. La: Sesiunea de Comunicări
ŞtiinţificeEdiţia a IV-a , Universitatea „Aurel Vlaicu‖, Arad, 30-31 octombrie 1997Cap3.
[10] Fulga, M.,Evaluarea populatiei expuse la zgomotul urban supravegherea starii de
sanatate a populatiei in expunerea la zgomot. În : Programul naţional de monitorizare a
factorilor determinanţi din mediul deviaţă şi muncă.București2009. p.42-48 .
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PROMOTING THE MANAGEMENT BASED ON KNOWLEDGE IN
THE ROMANIAN ORGANIZATIONAL ENVIRONMENT
Lecturer PhD. eng. Alin NIOAȚĂ, Engineering Faculty, ‖Constantin Brâncuși‖ University,
[email protected]
Lecturer PhD. eng. Florin CIOFU, Engineering Faculty, ‖Constantin Brâncuși‖ University,
[email protected]
Abstract: The organizations based on knowledge are intelligent collective actors of the informational society
and they are determinant for affirming it as a knowledge society; belonging to the contemporary reality both as
an environment of professional and managerial environment and as an object of scientific research and strategic
project, they mark the convergence between two phenomena defining the human nature – the knowledge one and
the organization one – in a symbolic social construction for the ideas of collective competence, intelligent action
and sustainable performance.
Keywords: organization, management, scientific research, informational system, informational flow.
1. Introduction
The result of the knowledge revolution is constituted by the economy based on
knowledge. Even if the development level still places us far from the economically advanced
countries, the Romanian organizational environment cannot be an exception from the global
orientation of the contemporary society towards advanced knowledge and technologies.
Romania, in its commitment on the way to sustainable development, cannot get away from
the new organizational type belonging to the society based on knowledge.
At the level of the debates and of the theoretical analysis, the concepts of economy,
organization and management based on knowledge penetrated and are reinforced in the
university-academic environment. Also, the research projects meant for this field are already a
significant presence in the themes of basic and applicative research of the research institutes
and of the universities in Romania.
In this sense, we find a diversification of research in the management field, a
diversification leading to the approach of the complex problems of the organization and of the
management based on knowledge. Unfortunately, at the level of most of the organizations, the
capitalization of these concepts represents, in the best case, a far desideratum, a future
problem that the organization may absolve from at present. It is especially about the big
organizations with a less flexible management and less attached to the innovating approaches.
At the level of smaller firms with an emphasized extern exposure, it was outlined the
conviction according to which the only successful way on a long term is the adoption of a
different vision regarding the way of conceiving and practicing management. In this sense,
using the entire organization for creating, obtaining, assimilating, understanding and
capitalizing the knowledge are actions that started to be outlined. But it is true that the
institution of the managerial practices based on knowledge is still accomplished in
experimental forms in these organizations.
The management based on knowledge may be regarded as an approach involving
specific strategic actions directed to motivating the organization in the sense of accumulating
and capitalizing new knowledge by stimulating the continuous learning. Conceiving and
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practicing the management based on knowledge is for Romania an obvious necessity and the
guarantee of the sustainable development of the economy.
Creating a society based on knowledge and developing the institution processes at the
level of the organizations of the managerial practices based on knowledge are extremely
complex actions. At present, the role of developing and promoting these concepts belongs to
the scientific and academic environment.
By solid projects of scientific research, by strong actions of disseminating the research
results, the institutes, the universities should find solutions for crossing the limits
organizationally appeared. We may notice that, in the Romanian scientific environment, this
responsibility is assumed by the inclusion in the agenda of researching the themes referring to
the development of the organization by innovation and knowledge development. Scientific
research is the real source of revolutionizing the knowledge, the guarantee of the Romanian
economy progress on an average and long term. The application in practice of the
development projects, at a national scale, of an economy based on knowledge is not easy, as it
requires top specialists in whose training and forming the Romanian university education is
significant.
In the conditions of the world tendency of orientation to the society based on
knowledge, Romania is forced to respect the same direction if it wants a dignified position in
the future economy. The role of scientific research is essential in accomplishing this
desideratum. We should priorly launch research programs that should drive the scientific
investigation in the field of the management based on knowledge, stimulate the cooperation in
the scientific and economic environment, promote the excellence in research and support the
economy based on knowledge. The management based on knowledge is a very dynamic field
at the international level at present and it deserves all the attention including from the
management of the firms in Romania, given the impact these aspects have at the level of the
organizations on a market with increasing competitiveness. Unfortunately, there are relatively
few persons/firms in Romania that have a good understanding/competence in this field and
that could implement successful projects, based on a diagnosis-analysis/audit of the real
organizational needs and of the firm-client strategy.
2. Managerial informational system
The managerial informational system represents the ensemble of information,
informational flows, procedures and means of treating the information meant to contribute to
the accomplishment of the main objectives of the commercial society or of the autonomous
overhead.
The managerial informational system appears as a complex of people and practical
activities, of equipments and procedures, directed towards modelling the managerial
processes by means of operations of processing the information, based on using the
mechanization and automation means.
The managerial informational system supposes the use of the modern methods of
calculation and economical analysis, programming, optimizing the managerial processes and
elaborating provisional models, and also typifying schemes of informational circuits at the
level of the manager, of its immediate helpers, of the leaders of subunits and of the
employees of the economical unit.
The managerial informational system provides the knowledge of the realities of the
commercial society and it contributes thus to elaborating and accomplishing the purposes
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established by the manager. By this, all the information necessary for funding the strategic
decisions and the ones of managerial economical politics are obtained, the data base
necessary for elaborating the models of economical increase of the unit is supplied, the
information regarding the accomplishment of the purposes and objectives is collected,
processed and transmitted, the intensity of the connections in the managerial space is
measured, the appeared deviations and their causes are determined.
All the projects of accomplishing organizations based on knowledge need strategic
commitment and managerial ingeniousness in combining the computerized facilities of
intelligent assistance with reinforced organizational practices referring to the innovation, the
learning and the partnership interactivity.
In the management of the commercial society, the informational flow circulates
between the general assembly of the shareholders and the administration council, between
this and the executive committee, between this and the production sections and the
functional device, between them and the employees of the commercial society.
Using the information represents an important stage whose purpose consists of using
the information received for establishing the measures necessary for improving the work of
the manager, of its helpers, of the subunits and of the employees. Regarding the possibility
offered by the information to be used, it becomes a factor of the management of the
commercial society, of obtaining new knowledge and of influencing on the content and the
conceptions of the entire unit staff.
3. Management of organizational knowledge
The knowledge management may be defined as a strategically directed approach of
motivating and easing the involvement of the organization members in developing and using
their cognitive skills, by the capitalization subordinated to its ensemble purposes, of the
informational sources, to the experience and skills of every one of them.
In the organizational environment, knowledge comes from the information changed by
the ones owning them into a capacity of efficient action, by assimilation and integrating
understanding. Based on Nonaka and Takeuchi‘s researches referring to the elaboration of a
typology of the forms of organizational knowledge, in the literature of the field, they
suggested to take over a distinction initially noticed by the epistemologist Polanyi: the one
between explicit (articulated) knowledge that is formable, accessible and communicable, on
one hand, and the implicit (tacit) knowledge that is subtle, deeply personalized, nonformalized and diffusely present in the organizational context.
In their functioning, the organizations build representations on their own knowledge
state; they deal with the challenge of finding ways of capitalizing what they know, but also
with the paradoxical finding that they are not fully aware of what they know and of what
they do not know. In this sense, we consider as anthological the statement made by the
former general executive of Hewlett-Packard firm, Lewis Platt: ‖If Hewlett-Packard firm
was aware of what it knows, we could become three times more profitable‖.
The knowledge base makes the behaviour of an organization to contain new present
and active strategic specific punts determining it:
- to represent in an integrating and transparent way the accumulations of explicit and implicit
knowledge existing at the individual level or at the group level or on artificial supports;
- to permanently extend the knowledge base by stimulating the processes of learning and
organizational innovation and by capitalizing their results;
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- to develop their skill of changing intelligently and opportunely the available knowledge
into successful actions;
- to acknowledge and to administrate their own ignorance.
The capitalization process of the intellectual actives is associated to the concept of
knowledge base, used here in an extended acceptation in report to the one in informatics. For
organizations, the knowledge base fully refers both to the personalized size of knowledge
present at the human bearers (individuals and groups) and to its artificial size present in the
intelligent computerized systems. Being conceived thus, the knowledge base presents the
attributes of an extended organizational memory meant to cognitively support specific
autonomous projects and to cumulatively benefit from their results.
The strategic punts mentioned above involve organizational actors in the
synergistically articulated behaviours, namely of co-elaboration (interactive generation of
new knowledge), co-learning (mutual validation of the new cognitive purchases), coadministration of capitalized knowledge. They refer to the organizational knowledge as a
resource, but also as a process, involving the placing of the actors animating them in a
community frame; here, the dominant relations are the horizontal ones (non-hierarchical),
such as interaction between counterparts, resulting thus systemic effects of their co-evolution
at the cognitive level.
The knowledge base also has an inter-organizational size; in the contemporary society,
it is typical for the organizations to find and mutual evaluate, by means of their environment,
to follow the field leaders, to learn one from the other, to use imitation, to have
confrontations between them or to ally in order to create and use new ideas. In such
conditions, the extra-organizational environment becomes richer in knowledge, a fact that
gives birth, for the organizations, to an extended scale of possible alternatives of
development and learning from outside sources, but also to exigent samples of performance
and in a permanent evolution as long as the knowledge advances.
4. Conclusions
For an informational society to develop as a knowledge society, it is decisively
conditioned both in Romania and internationally by the presence of intelligent organizations
with advanced capacities of administrating their collective skills as performance sources.
The knowledge base of the contemporary organizations is unavoidable, it results from a level
of systemic complexity crossing the rigid limits of the traditions hierarchies and involves the
appearance of non-hierarchical organizational practices and configurations; from strictly
inertial evolutions, such as self-organization, maximum insular solutions may result,
potentially ad-hoc articulated; in exchange, obtaining integrated, viable systems supposes a
transforming intervention on existent organizations or creating new ones, dedicated to the
wanted purpose.
References
[1] Băcanu B., - Strategic Management, Economical Press, Bucharest, 2001.
[2] Cornescu V., Mihăilescu I., Stanciu S.,- Organizational Management, All Beck Press, Bucharest, 2003;
[3]. Nicolescu Ovidiu, Verboncu Ion, - Bases of Organizational Management, University Press, Bucharest,
2008;
[4]. Nicolescu O., Nicolescu L., - Economy, Firm and Management Based on Knowledge, Economical Press,
Bucharest, 2008;
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DEVELOPMENT OF THE TEST METHODS OF THE CONVEYOR
BELTS USED IN ENVIRONMENTS ENDANGERED BY EXPLOSION
HAZARDS
Ph.D.Eng. Florin Adrian PĂUN – INCD INSEMEX Petroşani, [email protected]
Ph.D.Eng. Mihaela PĂRĂIAN – INCD INSEMEX Petroşani, [email protected]
Ph.D.Eng. Emilian GHICIOI – INCD INSEMEX Petroşani, [email protected]
Ph.D.Eng. Niculina VĂTAVU – INCD INSEMEX Petroşani, [email protected]
Ph.D.Eng. Leonard LUPU – INCD INSEMEX Petroşani, [email protected]
Ph.D.Eng. Adrian JURCA – INCD INSEMEX Petroşani, [email protected]
Abstract:Conveyor belts are used for a long period of time in the industry branches where potentially explosive
atmospheres could occur.
Dangerous phenomena which can be in direct connection with the use of conveyor belts are the ones
regarding:
- sparks influence over the coating layer and/or resistance internal structure of the stopped conveyor
belt;
- propagation of a flame along the length of a conveyor belt that was exposed to a energy source
relative high like a fire or due to blockage of a conveyor belt as a result of the driving mechanism still
operating, that generate a local heating of the conveyor belt in contact with the driving drum, rollers or any
other heating source generated by friction.
Determining the safety parameters characteristic of the
conveyor belts by employing test methods allows assessment of the safety level as well as certification of
their explosion protection quality when used in environments with explosion danger.
Keywords: conveyor belt, potentially explosive atmosphere, static electricity, flame resistance.
Introduction
Belt conveyors have been used for a long time in most of the industrial branches as well
as there where the likelihood of explosive atmospheres occurrence exists.
Unlike normal environments, in the ones with potentially explosive atmospheres the
fire/explosions hazard occurs, as consequence of various technological processes or accidental
leaks.
In order to mitigate explosion risk in these environments with potentially explosive
atmospheres, both equipment and its component (conveyor-transportation belt) must be of
special construction so as not to generate electric sparks, impact or friction mechanical sparks,
static electricity, hot surfaces or any other energy sources that could ignite the atmosphere.
The conveyor belt, as component of the conveyor, non-metallic, made of rubber or
polymers with or without insertions, during operation may build up static electricity charges,
thus gaining an electrostatic potential. On the other side, due to belt blockage and excessive
rubbing between it and conveyor's driving drum, high temperatures can be developed that
could lead to igniting the conveyor belt and further to its burning.
All these phenomena, strictly related to conveyor belts operation, show a high influence
on the safety level in technological areas where they are operating.
Having in view this aspect, identifying these phenomena is imposed as necessary;
likelihood and frequency of occurrence determination as well as determination of those
parameters upon which the safety level depends.
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New test methods for determination of the safety parameters of conveyor belts
The importance of determining the specific safety parameters of conveyor belts is given
especially by the need of establishing the safety level that has to be ensured regardless of
application of intended use.
In case of employing conveyor belts in environments endangered by potentially
explosive atmospheres, this importance is even greater due to the explosion hazard that may
occur at a certain moment.
In order to avoid this risk and to ensure a high safety level, the conveyor belts have to
comply with both constructive and safety requirements. The safety requirements indicators
addressed are in fact the safety parameters specific to conveyor belts intended for use in
environments with explosion hazard.
Within these parameters class, are the following: the electrostatic potential generated by
a conveyor belt during operation, electric resistance, resistance to friction on drum, resistance
to burning in gallery, flame resistance.
Initially, in order to determine these safety parameters, test methods given in specific
national standards and norms had been applied. Later, through Romania joining the European
Union and implicitly harmonization with member states legislation, determination of safety
parameters is carried out based on the requirements and test conditions given in the new
European standards.
Once the new standards adopted, new test methods had been developed and
implemented within the testing laboratory, at the same time with carrying out new test stands,
modern, endowed with last generation apparatus.
Test method to determine electrostatic potential generated by a running light conveyor
belt in operation
The standard providing the test method is SR EN ISO 21178:2007 (SR EN ISO
21179:2007), applicable for conveyor belts with a inner conductive layer. The admittance
condition is not to generate electrostatic charges that could generate a surface potential greater
than 500 V [4], [5].
In special conditions of use, electrostatic high amount of static charges that generate a
surface potential greater than 500 V may be produced through the rubbing between the belt
and the conveyed products or by rubbing between the transported products themselves, or by
displacement of belt over the rollers or return drum, in this case dangerous products conveyed
are the ones in bulk.
The test is carried out on a new conveyor belt, unused and not submitted to test earlier
than five days since manufacturing date; it shall show no traces of contamination or surface
faults.
The conveyor belt to undergo the test shall have the length of (2500 ± 50) mm and width
of (100 ± 1) mm and shall have no ends. During the tests two results are important and have
to be taken into consideration, namely the maximum value reached by the surface potential
and a value taken as a constant (for example when after 10 minutes the charge accumulated is
below 10%) [6].
In order to determine the electrization potential a special test stand is required, through it
a test sample (conveyor belt) having the above mentioned sizes is statically charged while
rubbing on drums with a velocity of 5 m/s, ensuring a certain tension in the belt and under
specific environment conditions.
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Temperature and relative humidity in the test room are relevant and they have to be
measured and recorded.
In its motion, the belt sample accumulates charges of electrostatic kind as consequence
of its friction on the two drums, thus generating an electrostatic field.
In relation to the device used for recording, either electrostatic intensity E in volts per
meter or, if the measuring device has a direct potential U reading, this value in volts can be
recorded.
Figure 1 shows the test stand to determine the electrostatic potential generated by a
running conveyor belt [1].
Fig. 1 - Test stand for determination of the electrostatic field generated by a light transporting belt in operation
Keyword: 1 - electrostatic field measuring/recording device; 2 - return drum; 4 -metallic plate, 600 mm×200
mm; 5 - metallic plate 200 mm×200 mm; 6 - driving drum; 7 - metallic frame; 8 - tensiometric cell and digital
indicator; 9 - motor gear.
Test method for determination of flammability at fire simulation (propane burner)
The test consist in determination of conveyor belt characteristics regarding flame
resistance.
Method A – Test with a single propane burner on a length of 2 m
The test is carried out on two belt samples, each of 200 mm length and 1200 mm width
or on all width if the conveyor belt has a width lesser than 1200mm; the test samples have to
be kept away from moisture 24 hours before the test, at a positive room temperature in order
to avoid any residual bending [1], [8].
The test samples are placed on a trestle (fig.3) which is placed in a gallery with a cross
section area of maximum 6 m2, and then the propane burner is placed under the trestle (fig. 2).
The exposure time on flame is 10 minutes then they are let to self extinguish subsequently the
length of undamaged belt has to be measured.
The admittance condition for the conveyor belts in categories 4A, 4B, 5A, 5B and 5C
submitted to tests according to method A of SR EN 12881-1:2003 is the undamaged belt
length has to be greater than 100 cm on the tested belt [4], [5].
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Method C – Flame propagation test at medium scale
The test is carried out on two belt samples, (conveyor belt with 1500 mm length × 230
mm width ). The test samples have to be weighed and placed on an estacade located in the
flame testing gallery, having of small dimensions, under which, farther a 6 nozzle burner is
placed, fed with propane from a propane cylinder. The air velocity is adjusted in the testing
gallery at (1,0 ± 0,05) m/s. The gas flow fed by the cylinder is adjusted at 350 l/h, then the
burner is lit up and the test begins, for a period of 50 minutes [2], [8].
At the end of the testing, the sample is weighted. The test result is expressed by the
length of intact sample, temperature increase and length of consumed belt have to be
measured [2], [8].
Fig. 2 – Burner for test method for determination of
flammability of the conveyor belts
Fig. 3 - Burner trestle to support the conveyor belt sample
Test method to determine the resistance to friction drum
The method of test to determine the propensity of a conveyor belt to generate heat flame
or glow when held stationary under a given tension, in surface contact around a rotating
driven steel drum is given in SR EN 1554 :2002 Conveyor belts. Drum friction testing. [7].
In order to determine the resistance to drum friction, a test piece of conveyor belt,
suitably mounted and tensioned, is wrapped half way around a rotating steel drum, simulating
a stalled belt. The test is continued at specified tensions for a given time period, or until the
belt breaks. The presence, or absence, of flame or glow is noted and reported and the
maximum temperature of the drive drum is recorded. The test is conducted in still air or/and
in moving air.
During the testing, the test piece is examined to observe any flame or glowing and
detaching of any incandescent particles either during the test or at the end of it.
The test stand for drum friction testing is shown in figure 4 and it consists in: steel drum;
drum temperature recording device comprising an aquisition data board and a portable PC, a
tensioning system able to apply incremental tensions, an anemometer and a compressor in
order to supply the required air flow [3].
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Fig. 4 – The test stand for drum friction testing
All the three test stands previously described had been carried out as subject of research
projects unrolled in the National Research "NUCLEU" Program, where accreditation of the
tests had been in view, in order to extend laboratory's testing capacity and implicitly the
conformity assessment ability; since it's a well knows fact that proving products conformity,
in this case of conveyor belt, with the European standards ensures the presumption of
conformity with the requirements of the related European Directive, which is the ATEX
94/9/EC Directive, since INCD-INSEMEx is conformity assessment Notified Body at
Brussels. The test stand according to Method C - medium scale flame propagation test is in its
course of being executed at INCD-INSEMEX Petroşani.
Conclusions
The conveyor belts having as intended use environments with potential explosive
atmospheres have to comply with the essential safety and health requirements regarding
explosion protection and prevention.
Development of the safety parameters specific to conveyor belts, through test methods,
allows an assessment of the safety level as well as certification of their explosion protection
quality when used in environments with explosion hazards.
The test methods allow ensuring repeatability and reproducibility of tests carried out in
various test laboratories, fact having a great importance since it offers a real basis of
comparison for the tests carried out in accredited laboratories, at European level, for the
purpose of obtaining an accurate assessment with the essential safety and health requirements.
Bibliography
[1]
[2]
322
Păun F., a.o.,: Proiect Program NUCLEU „Dezvoltarea facilităţilor de cercetare
privind riscul sau frecvenţa probabilă de producere a unor fenomene periculoase în
funcţie de circumstanţele specifice ale aplicaţiilor din atmosfere cu pericol de
explozie a benzilor transportoare (DFCBT)‖, 2010-2011.
Păun F., a.o.,: Proiect Program NUCLEU, faza V/2012 „Tehnologie pentru
încercarea benzilor transportoare la ardere la scară mică în conformitate cu
standardul european‖, 2012.
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[3]
[4]
[5]
[6]
[7]
[8]
323
Lupu L., a.o.; Proiect program NUCLEU „Dezvoltarea metodelor de evaluare
pentru instalatiile de transport cu banda destinate utilizării în minele subterane
grizutoase – echipament neelectric de grupa I – METBEN‖, 2010-2011.
* * *, SR EN 12882:2009, Benzi de transport de uz general. Cerinţe de securitate
electrică şi de protecţie împotriva inflamabilităţii.
* * *, SR EN 14973:2008, Benzi transportoare pentru utilizare în instalaţii
subterane. Cerinţe de securitate electrică şi de inflamabilitate.
* * *, SR EN ISO 21179:2007, Benzi uşoare de transport. Determinarea câmpului
electrostatic generat de o bandă uşoară de transport în funcţionare.
* * *, SR EN 1554:2002, Benzi transportoare. Încercări la frecare ale tamburului.
* * *, SR EN 12881-1:2008, Benzi transportoare. Încercări de simulare a
inflamabilităţii. Partea 1: Încercări cu arzător cu propan.
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INDUSTRIAL GAS PURIFICATION USE OF BIOFILTERS
Lecturer Irina Ramona PECINGINĂ, University „Constantin Brâncuşi‖ of Tg-Jiu,
[email protected]
Abstract. Biological filtration systems is one of the current alternatives to remove residual volatile components
of the air through biological means, without affecting the natural environment. Biofilters have a technology that
uses microorganisms (bacteria) to treat emissions, in a secure economic and environmental quality. Biofilters
consist of porous filters, which is distributed flue gas stream.
Key words: biofilters, biofilm, microorganisms
1. Introduction
Air pollutants may be alien substances present in atmospheric composition or
substance, depending on their concentration and time of action, have a harmful effect on
health and environment, by default, man.
Biological filtration systems is one of the current alternatives to remove residual
volatile components of the air through biological means, without affecting the natural
environment.
Due to the metabolic capacity of aerobic species to degrade different volatile organic
substances, they are subject to microbial oxidation processes in the presence of atmospheric
oxygen after prior solubilization in aqueous medium, so that any gas to be completely free of
any compounds residual.
Biofilters have a technology that uses microorganisms (bacteria) to treat emissions, in
a secure economic and environmental quality. Biofilters consist of porous filters, which is
distributed flue gas stream.
Organisms that eat the waste gas are attached to the porous substrate. Biofiltration
process is similar to the conventional treatment of the precipitate obtained, in which
microorganisms are used to completely oxidize organic compounds in the form of CO2 and
water. Biofilters are useful for controlling emissions from composting operations, the waste
gas recovery processes in food, petrochemical, metallurgy, etc.
2. Biofiltration process description
Biofilters are technological facilities, such as fixed-film biological reactors that use
microorganisms attached to the substrate material. These substrates can be made of: compost,
peat, bark, soil or inert materials to convert waste products organic or inorganic CO2 and
water. Substrate provides structural support and nutrients essential for growth and
multiplication of microorganisms. Porous structure of the substrate provides an optimal
surface at a reasonable pressure drop of gas.
As the gases are passed through the reactor, the pollutants diffuse into the biofilm.
Pollutants are then decomposed by aerobic biodegradation process. Biofilters are economical
when applied to gas streams with low concentrations (<1000 ppm), rich in oxygen.
Decomposition efficiency greater than 90% can be achieved only if the water-soluble organic
substances such as alcohol, aldehydes and amines, or of the inorganic high solubility in water,
such as H2S and NH3.
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The main stages of the biofilter are shown schematically in figure 1 and consists of the
following technological operations:
 collection of the raw waste gas production or processing;
 transportation of gas by pipeline network, with a special pumping device;
 waste gas pretreatment to remove dust and particles of impurity;
 optimal temperature adjustment;
 adjusting the relative humidity until saturated, filtering particles and/or temperature
adjustments are often combined with equipment adjustment gas moisture content.
 decomposition of pollutants by microorganisms fixed on biofilter
Fig.1. Schematic representation of a biofiltration system
Biofilter efficiency is directly proportional to the quality of filter material and the
conditions in which the biofiltration process (tun uniform air distribution, degree of
humidification, drainage system). Since the composition of bacterial species are used as
biofilter media biofilters, they must be properly prepared and fertilized in accordance with
specific nutritional requirements of such microorganisms.
Broths are made from high quality raw materials that can guarantee the efficiency of
these bacteria supply nutrients for a long time. Correct structure of the material creates the
optimal conditions for development of low pressure and, therefore, to obtain as reduced
operating costs. The finished product of biological decomposition, in the ideal case, carbon
dioxide, water and bacterial biomass.
The pollutants are absorbed on the surface of the filter is then decomposed by
microorganisms present in an aqueous solution trickles down the filter constant. This method
is suitable mainly for water-soluble solvents.
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Composition and activity of microorganisms are provided, optimally, only when the filter
layer and the design and construction biofilters certain conditions are met:
 Design and construction. Capacity and efficiency of biofilter operation are directly
proportional to the active surface, the vacuum space of the filter efficiency in
achieving the targets, types of gas and gas loading. A proper design of the biofilter
principal components is very important to ensure a viable and efficient operation in
terms of cost.

Raw gas composition. First, the raw gas amount to be determined under biofiltration.
To ensure both a reasonable extraction efficiency and a reasonable life of
microorganisms, raw gas flow must include: an oxygen concentration equal to the
ambient gas concentrations below lethal to the microorganisms used and types of
microorganisms and bacteria lethal gas should be in the raw gas stream.

Transportation of raw gas. The gas is collected from the processing and transport by
pipeline, and fans using pressure boosting, the preconditioning equipment.
Preconditioning raw gas. To ensure destruction efficiency and lifespan biofilter, raw
gas stream must be adjusted before the gas is introduced into the biofilter safe to come
in preselected particle load, temperature and humidity.
Preconditioning particles. Loading strong with heavy particles (dust, grease, oil and
other aerosols) of gas, may be critical to the filter bed porous structure, resulting from
this increase in pressure loss. Oils and heavy metals are deposited on the filter bed can
be poisonous to living organisms in the biofilm .
Temperature. Temperature operation of a biofilter is controlled primarily by
temperature gas treatment subject. Average operating temperature recommended for
destruction efficiency is between 20 to 40 C°, with optimum temperature of 37 C°. At
low temperatures, bacterial growth will be limited and extremely low temperatures,
the bacteria will be destroyed. Above average recommended bacterial activity is also
reduced. extremely high temperatures will kill bacteria in the filter bed. If gas flow is
at a very high temperature (above 100 C°), the cost of cooling gas can be stored so
high, that may be more effective odor control some conventional methods such as
thermal oxidation.
Humidification. Inhabited by organisms that digest pollutants in a thin layer of water,
called biofilm, which encircles the filter substrate. Insufficient humidity may damage
the filter, resulting in reduction of surface active and untreated gas leak. Insufficient
moisture can also lead to breaking compression filter media, which would reduce the
active area and the untreated exhaust gases. Humidification of the gas flow is the
preferred method of transport, which is kept moist filter bed. Humidity is usually
added gas flow after fitrare stage, spraying water or steam. It is recommended to add
moisture directly above the filter bed to maintain moisture, because it could cause
local drying of the substrate. Also, the addition of hot water may reduce the activity of
microorganisms until water temperature reaches the final status of filtration bed.
Gas distribution system. Gas distribution system mission is to ensure an even
distribution of gas flow, preconditioned in all areas of filter bed. In models of flow
biofilter upstream gas distribution system provides: drainage environments, collecting,





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transporting excess water inside the filter bed, surrounding soil prevents potential
contamination, leak from the filter, a structural basis for the filter bed environment.
Gas distribution system may be composed of a network of perforated pipes, cracked or
a concrete block exits or metal bars. When there are limitations of space, is used to
filter one level. In areas where space is limited using multistage filters. If treated
inorganic components will be used building materials resistant to corrosion due to
acidic reaction bioproduct
 Filter array. Desire to preserve the effectiveness of cleaning the filter is the materialsupport to ensure a sufficient supply of nutrients for the microorganisms most
frequently used biofilters beds today are: soil or compost, leaves, peat forest, bark,
wood chips, paper or other organic material. These materials are arranged in the form
of layers through which the waste gas stream. Longer work because the
microorganisms, the filter material is gradually transformed as compost. For this
reason, it can lead to clogging and failure of the biofilter, which increases the loss of
gas pressure in the filter layer. To maintain efficiency filter material filter should be
replaced every 3 to 5 years. Are allowed inactivity period of several weeks, during
which organic filter material serves as a nutrient for microorganisms.
The filter selection should consider the following:
- Particle size and porosity of the filter environment, because efficient operation
is directly related to the biofilm surface area available;
- Filter medium must be a source of inorganic nutrients for microorganisms, and
for the duration of operations, these may be added periodically inorganic
nutriments in bed;
- Sealing of the filter bed will lead to the formation of gas channels and increase
pressure loss;
- eed good characteristics of the bed drained to ensure that reaction products are
easily removed by the filter medium;
- Any flow are generally recycled through the process of humidification to
reduce wastewater flow;
- Filter medium must have buffering capacity to maintain the pH at least 3,
particularly when necessary to reduce the inorganic components;
- Filter medium must be composed of materials with irritant odor.
Before entering the biofilters of waste gas containing pollutants, it shall be, in each case,
a preliminary treatment. Reinstatement in service to the biofilter must be taken into account,
where applicable, between the populations of microorganisms to adapt to new conditions of
existence. This method is used for organic compounds that are soluble in water and can be
decomposed microbiologically. Natural microorganisms used in biofilters are the same fungal
and bacterial species that are used routinely in activated sludge wastewater treatment. Also
were obtained and genetically modified organisms through genetic engineering techniques
that are designed decomposition of aromatic organic compounds by chemical synthesis
(xylene and styrene). Among the various research in progress, trying to widening the number
of chemicals that can be biodegraded, which will contribute to lowering the cost and size of
filter beds, currently used by reducing the time necessary for digestion.
The most common species of microorganisms are presented in table 1.
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Table.1. Species of microorganisms used in biofiltration
Bacteria
Actinomyces sp.
Micrococcus sp.
Bacillus cereus
Streptomyces sp
Fungi
Penicillium notatum
Cephalosporium sp.
Mucor mucedo
Aspergillus niger
3. Conclusions
 Biological filtration systems is one of the current alternatives to remove residual
volatile components of the air through biological means, without affecting the natural
environment.

Biofilters are technological facilities, such as fixed-film biological reactors that use
microorganisms attached to the substrate material. These substrates can be made of:
compost, peat, bark, soil or inert materials to convert waste products organic or
inorganic CO2 and water.

This method is suitable mainly for water-soluble solvents
References
[1] Pecingină I.R., Environmental Biotechnology, Ed C.T.E.A., Bucharest, 2010, p.171-185
[2] Petre, M., Teodorescu A., Environmental Biotechnology, Vol. I, Ed. CD Press,
Bucharest, 2009
[2] Petre, M., Teodorescu A., Environmental Biotechnology, Vol. II, Ed. CD Press,
Bucharest, 2008
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EFFICIENCY ANALYSIS OF THE LIQUID CONTROLLER WITH A
RING VALVE
Professor Engineer PhD. BEAZIT Ali ―Mircea cel Bătrân‖ Naval Academy, Constanţa,
Romania, e-mail: [email protected]
Professor Engineer PhD. Gheorghe SAMOILESCU ―Mircea cel Bătrân‖ Naval Academy,
Constanţa, Romania, email: [email protected]
Abstract: This paperwork studies the efficiency of the liquid controllers with a ring valve analysing the liquid
running through the controller, the variation of the pressure and its speed for various forms of the ring valve
controller.
Keywords: controller with a ring valve, flowing, energy lines, pressure decline, speed
1.Introduction. Hydraulic contacts (flowing spaces between the mobile and fixed pieces
of the devices)
Multiple hydraulic contact, actually, characterises the liquid controllers (with a ring or
a hinged valve) used in the actuation or self regulating hydraulic systems. Unlike the singular
contact, in this case, there interfere, in an unique functionality, simultaneous flows in a
contact assembly, connected between them in serial and/or in parallel way. In order to
determine the interested relation Q = f(x, Δp), where Δp = pi – pm (and pm is the pressure drop
in the actuation hydraulic engine), there must be considered not only the possible leaks from
the contact (the controller) that connects the pump and the engine entrance, but also all
contacts that modify themselves unitively (with the same variation of the x opening) with the
mentioned contact, which are higher or lower from it. Practically known situations are
multiple, they depend on the following main factors: type of the power supply (with a
constant pressure or a constant flow), type of the controller (with a valve – with 1, 2, 4 active
edges – or with help switch), type of the actuation engine (differential or undefferential gear),
type of valve (with a positive, null or negative cover, symmetrical or asymmetrical).
Uneven characteristic ecuation of the controllers with negative cover fed at a constant
pressure can be expressed in the general form:
Qm  c1c2 c4  c5 pm  c4  c5 pm  c1c3 xm c4  c5 pm  c4  c5 pm  f1 ( pm )  xm f 2 ( pm ) (1)




where: xo [cm] represents valve‘s negative cover;
D [cm] represents the valve‘s diameter for the active edge.
The relation (1) expressed for the four active edge valve fed with a constant pressure
pi (according to the data from the following table) can be resumed to the formula (2):
No. of
active edges
4
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c1
c2
c3
c4
1
1
2
1
1
1
1
1
c5
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1 p
1 p
 (1  x)
2
2
Where one must remember that the variables are expressed non-adimensionally
p
x
Q
1
p m ; Q
x m
 m ;
pi
x0
c d D 2 /  x0
pi
Q  (1  x)
(2)
For the four active edges valve, fed with a constant flow Qi, the unliniar characteristic
eqution is as follows:
 (1  x 2 )  (1  x 2 ) 2  4[ x  ( x 2  1) 2 ] p
(3)
Q
 2x
Where one must remember that the variables are expressed in an nondimensionalised form:
Q
p
x
Q  m ; p  (cd D 2 /  x0 ) 2  m2 ; x  m
Qi
x0
Qi
Just as with the singular contact, in practice, it is usually necessary to present ecuation
(1) or (2) at a liniar form. In order to function in a narrow field of the x opening variation.
This is necessary for the mathematical pattern-making of the hydraulic systems (especially for
those with self regulation) in order to analyse them dynamicly. For partial deviations of the
general equation (1), according to the pre-established definitions of the transmission gains co ¸
Eo, one can arriave at the replacement of the unliniar equation (1) with a liniar one:
A 2 c0
(4)
Q  Ac 0 xm 
p m
E0
Values of the transmission gains co and Eo are determined by the controller‘s
construction. As an example, we will consider controller 4/3 presented in Figure 1
Figure 1 Controller 4/3
In Figure 2, there are presented the 3 shifting positions of the controller.
R
A
P
B
R
R
Figure 2 / Position 1
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A
P
B R
Figure 2/ Position 2
R
A
P
B
R
Figure 2/ Position 3
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2.Study of pressure drop in the controller
We propose to study the pressure drop between two passing positions of the controller,
for three controller contruction solutions, as follows:
 Controller with a straight edge valve, Figure 3 a);
 Controller with a slightly conoidal edge valve, Figure 3 b);
 Controller with a round edge, Figure 3 c).
a)
b)
c)
Figure 3 Three controller contruction solutions
We consider the controller in position 3. The labour fluid will flow from pump P towards pipe
A (Figure 4) with a constant rate of 4.5 m3/h. The controller has the same size as the valve
presented in Figure 5, the diameter of the feedings in which flows the liquid is of 10 mm.
A
P
Figure 4
Figure 5
Figure 6
With the help of COSMOS FloWorks software, we analyse the flowing of the fluid
through the controller above presented. The analysis field contains the internal volume where
the fluid from a cube flows just like in Figure 6. The limit conditions are the following: at the
entrance, through the feeder of the pump, it is introduced a fluid rate represented with red
arrows in Figure 6, and at the exit, the fluid will meet a potential pressure represented with
blue arrows.
A. From the model from Figure 3 a) there are the following graphical results:
 Flowing on a section from the volume of the liquid disposed on the frontal side:
Representation on the perimeter, Figure 7 a); Representation on the perimeter with the
speed vectors, Figure 7 b).
 Representing fluid lines: frontal side, Figure 7 c); on the inferior side of the valve
(opposite the feeders), Figure 7 d); on the superior side of the valve, Figure 7 e);
In perspective, Figure 7 f);
 Variation graphics of the fluid‘s parameters on a curve from the interior of the
controller, parallel with the valve: Variation of speed Figure 7 g);
Variation of pressure Figure 7 h).
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a)
Figure 7 g)
b)
c)
d)
e)
f)
Variation of speed
Figure 7 h) Variation of pressure
B. From the model from Figure 3 b) there are the following graphical results:
 Flowing on a section from the volume of the liquid disposed on the frontal side:
Representation on the perimeter, Figure 8 a); Representation on the perimeter with the speed
vectors, Figure 8 b);
 Representing fluid lines: frontal side, Figure 8 c); on the inferior side of the valve
(opposite the feeders), Figure 8 d); on the superior side of the valve, Figure 8 e); In
perspective, Figure 8 f);
 Variation graphics of the fluid‘s parameters on a curve from the interior of the
controller, parallel with the valve: Variation of speed Figure 8 g); Variation of pressure Figure
8 h).
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a)
b)
c)
d)
e)
f)
Figure 8 g) Variation of speed
Figure 8 h) Variation of pressure
C. From the model from Figure 3 c) there are the following graphical results:
 Flowing on a section from the volume of the liquid disposed on the frontal side:
Representation on the perimeter, Figure 9 a); Representation on the perimeter with the speed
vectors, Figure 9 b);
 Representing fluid lines: frontal side, Figure 9 c); on the inferior side of the valve
(opposite the feeders), Figure 9 d); on the superior side of the valve, Figure 9 e); In
perspective, Figure 9 f);
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 Variation graphics of the fluid‘s parameters on a curve from the interior of the
controller, parallel with the valve: Variation of speed Figure 9 g); Variation of pressure Figure
9 h).
a)
c)
d)
e)
f)
Figure 9 g) Variation of speed
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b)
Figure 9 h) Variation of pressure
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3.Conclusions
One can notice from the three sets of analyses done that there were obtained different
results. The analysis aim was to determine the best construction solution from a fluid flow
point of view through the hydraulic slots, feeders and contacts.
The less advantageous is the one presented in case B, in which the fluid lines are
distributed uneven on the surface of the core bar between the two pistons of the hydraulic
controller. This uneven distribution determines different requests upon the valve in different
plans that may lead to a fast deterioration of the centering and actuation mechanisms of the
controller and may lead to fluid leaks between its pistons.
4. References
[1] DODDANNAVAR Ravi, BARNARD Andries – Hydraulic System, Operation and
Troubleshoting for Engineers&Technicians, Elsevier, Burlington, 2005.
[2] PETRE Pătruţ, NICOLAE Ionel – Acţionări hidraulice şi automatizări, Editura
Nausicaa, Bucureşti, 1998.
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STATISTICAL HYPOTHESIS TESTING USING FUZZY LINGUISTIC
VARIABLES
Iuliana Carmen BĂRBĂCIORU , Univ. Lecturer Ph. D.
‖ConstantinBrâncuşi‖ University ,Tg. Jiu
Abstract: This work proposes a fuzzy statistical test of fuzzy hypotheses usinglinguistic variables. The method is
based on Zadeh’s principle: the fuzzy population mean in the null hypothesis is converted to fuzzy numbers using
conversion scales proposed by Chen and Hwang (1992). The method proposed by Chen et al [10] reflects
thereal situation than conventional methods.
Keywords: fuzzy numbers, fuzzy sets, fuzzy random variables, hypothesis testing,
1. Introduction
Most of our traditional tools in descriptive and inferential statistics is based on crispness
(preciseness) of data, measurements, random variable, hypotheses, and so on. By crisp we
mean dichotomous, that is, yes-or-no type rather than more-or-less type. But there are many
situations in which the above assumptions are rather nonrealistic, such that we need some new
tools to characterize and analyze the problem.
By introducing fuzzy set theory, different branches of mathematics are recently studied.
But probability and statistics attracted more attention in this regard because of their random
nature. Mathematical statistics does not have methods to analyze the problems in which
random variables are vague (fuzzy). For example, if X is a random variable taking values:
small, medium and large, the probability of small, medium and large respectively, what about
the media and the dispersion of X?Asbetween theconcept ofBooleanlogicisasubset
ofcloselyrelated, so exists betweenthe theory offuzzy logicandfuzzysubsets.
Xconsidersomenon-emptya
set.
Theclassical
theoryof
sets,
asubsetAofXcanbehighlightedbyitscharacteristicfunction,
Therefore, the truth or falsity of claim ―x is in A‖is determined by the ordered pair
(x,
.Moreover, the ordered pair determines the subset A.Similarly, a fuzzy subset of X
can be emphasized by a (x,
ordered pairs where
is the membership function of A.The degreeoftruthorfalseclaim"xisA" is determinedby
theorderedpair (x,
.Let any non-empty a set X (the universal set). A fuzzy set of X is
characterized by membership function
and
is interpreted as the degree of
membership of element x in set A.In this sense, a fuzzy set of X can be regarded as a
function
. We note F (X) family of fuzzy sets of X.
The support of A, denoted supp(A), is the crisp subset of X whose elements all have nonzero
membership grades in A
supp(A) = {x ∈ X|A(x)> 0}.
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Let a,b,c,d∈R, a<b<c<d.A fuzzy set A is called trapezoidal fuzzy set [a,b,c,d]if its
membership function has the following form:
(1)
Let (Ω,F) be a measurable space. Any measurable function X:(Ω,F) (R, B) is called a
random variable. Let P a probability measure on (Ω,F), (and hence (Ω,F,P) be a probability
space). Then PoX-1 is a probability on (R, B) which is called the induced probability or the
distribution of X, so that
(2)
Where f(x) is the Radon-Nikodym derivative of PX with respect to ν (aσ-finite measure). The
function f is called the probability density function of X with respect to the measure ν.The
measure ν usually is ―counting measure‖ or ―Lebesgue measure‖, hence PX(A) is calculated
by
or
, respectively.Let A be a fuzzy subset of X; the support of A,
denotedsupp(A), is the crisp subset of X whose elements all have nonzero membership grades
in Asupp(A) = {x ∈ X|A(x) >0}. We not
. Let X=(X₁, X₂,..., Xn). We
say that is a random sample of size nfrom a population with probability density functionf(x), if
Xi‘s are independent and whose probability density functions are f(x) (Xi‘s are identically
distributed). In this case, we have
,
(3)
wherex=(x ₁, x ₂,..., xn) is an observed value of X.
2. Fuzzy hypotheses testing
Decision making in the classical statistical inference is based on crispness ofdata,
random variables, exact hypotheses, and decision rules and so on; see e.g.Lehmann [16],
Casella and Berger [8]. As there are many differentsituations in which the above assumptions
are rather irrealistic, therehave been some attempts to analyze these situations with fuzzy set
theoryproposed.
In this manner, one of the main areas is testing statistical hypothesis infuzzy environment.
Arnold [2], [3], for the first time, presented an approach how to test fuzzilyformulated
hypotheses with crisp data in which the probabilities of type I and type II errors are defined.
The same problem is considered by Delgado et al.[11] with another approach. Taheri and
Behboodian [25] stated and proveda Neyman-Pearson lemma for fuzzy hypotheses testing
with crisp data. Son et al. [23], using a generalizedNeyman-Pearson lemma, presented a
locally most powerful fuzzy test and studied its application in signal detection. Watanabe and
Imaizumi [26] introduced a testing method of a fuzzy hypothesis for random data, in whichthe
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conclusion from the test is also fuzzy. Saade and Schwarzlader [22] andSaade [21] developed
fuzzy hypothesis testing for hybrid data under which one hypothesis is a mixture of a random
and a fuzzy component. Casals [5]and Casals et al. [6], [7] discussed statistical hypothesis
testing based on amodel represented by fuzzy events, both by classical and Bayesian
approaches.Taheri and Behboodian [25] studied fuzzy hypothesis testing by aBayesian
approach, both for crisp and fuzzy data. Grzegorzewski [12] proposeda method for testing
hypothesis with fuzzy data which leads to a fuzzydecision result.Hypothesis testing based on
the fuzzy random variables has been consideredby some authors, e.g. Montenegro et al. [18].
Arnold and Gerke [4] havestudied testing fuzzy linear hypothesis in linear regression models.
We refer to Taheri [24] formore references about testing statistical hypothesis in fuzzy
environment.
Any statistical test of hypotheses is composed of the following elements [10],[18]
Null hypothesisH0 : the hypothesis to be tested
Alternative hypothesis, Ha : the hypothesis to be accepted in case H0 is rejected.
Test statistic : a function of the sample measurements upon which the statistical decision will
be based.
Rejection region, RR :specifies the values of the test statistic for which the null hypothesis is
rejected.
Chen [10] proposed a numerical approximation which linguistic variables are fuzzy
numbers associated.Following Zadeh's extension principle, fuzzy statistical hypotheses is the
following:First, the population mean in the null hypothesis is started in linguistic variables
such as H0 : the average degrees reaches quite level, and then one figure is selected from the
eight conversion scales in Chen , containing all of the linguistic variables specified by a
decision maker and using the fuzzy numbers in that figure to specify the meanings of the
linguistic variables. Moreover, the samples‘ linguistic variables are converted to trapezoidal
fuzzy numbers by the selected conversion scale. D is the difference between two membership
functions thus calculated to:
(4)
MR ratio is calculated as the ratio
(5)
If the two membership functions are equal
when MR = 1 and the null
hypothesis is verified. When you support the two membership functions do not overlap in any
point; or very little overlap, MR = 0, and there is reason to reject the null hypothesis. MR
represents the possibility of accepting the null hypothesis. The reject area , RR, is chosen as a
critical matched ratio, when MR<RR and then the null hypothesis is rejected and vice versa.
When MR≥RR, H0 is accepted.
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3.Illustrative example
This section presents an example to illustrate testing of hypotheses concerning a fuzzy
population mean using linguistic variable. We believe the right-sided fuzzy hypothesis test.
Unlike Chen [10], who works with a particular case of trapezoidal fuzzy numbers,
[a,b,b,c],we will take the form of trapezoidal fuzzy numbers[a,b,c,d].
ExampleA company out to contest the post of designer. For this purpose it makes up a panel
of threeexperts, to use four linguistic variables: 1:―unsatisfying‖, 2:―satisfying‖, 3:―right‖
4:―veryright‖. Each expert was allowed to select only one linguistic variable for each
candidate. Seven candidates were presented. Although few candidates have presented, the
company thinks that the average degree of candidates should reach a high level. For this
purpose it is decided that assume the null hypothesis is, H0 : the average degrees of candidates
reaches quite a high level. The decision maker selects the membership function of [10] in the
right-sided test because of the use of four linguistic variables.
The ―very right‖ of the membership function is considered to be the
membershipfunction of the null hypothesis and the trapezoidal fuzzy numbers mean is
[0.9,1,1,1]. The decision maker adopts a loose principle and sets RR as 0.1. The linguistic
variables ―unsatisfying‖=[0,0,0,0.5], ―satisfying‖=[0,0.25,0.5,0.75], ―right‖=[0.7,0.75,0.8,1],
―veryright‖= [0.9,1,1,1]. Therefore, each candidate is assigned four linguistic variables
according to the three experts‘evaluations, so the seven candidates have a total twenty one
linguistic variables. These twenty one linguistic variables are displayed as matrix A:
The values 1,2,3,4 of linguistic variables in matrix A coordinate with
trapezoidal fuzzy numbers [0,0,0,0.5], [0,0.25,0.5,0.75], [0.7,0.75,0.8,1] and [0.9,1,1,1]
respectively. The valuesof linguistic variables in matrix A can be calculated from equation
(4), and the fuzzy mean of every candidate is obtained. For example, the calculation process,
by each de fuzzy mean of the first candidate is a determined, is a follows:
Fuzzy mean of the seven candidates is:
Candidate i Fuzzy mean
1
2
3
4
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[0.766,0.833,0.866,1]
[0,0.083,0.166,0.583]
[0.833,0.916,0.933,1]
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5
6
7
[0,0.166,0.333,0.666]
[0.9,1,1,1]
[0.233,0.333,0.433,0.75]
The membership function of the first candidates, for example,
the relationship is:
calculated according to
The ―very right‖ of the membership function is considered to be the membership function of
the null hypothesis and the trapezoidal fuzzy numbers mean is =[0.9,1,1,1]. The
membership function corresponding to
is:
Using equation (4) we obtain
Equation (5) determine MR1 for candidate 1:
For all seven candidates we obtain: MR1 =0.01, MR2 =0.43, MR3 =0, MR4 =0.6, MR5 =0,
MR6 =1, MR7 =0. Therefore, candidate 1 has 1% possibility to reach a quite high level, and so
on. Also, candidate 3, candidate 5 and candidate 7 not reach quite a high level.
Finally, these seven MR results are compared with RR=0.1: MR2 =0.43, MR4 =0.6 and MR6
=1 both exceed RR=0.1. Consequently, a decision maker should accept that the average
degrees of candidates 2, 4 and 6 reached quite a high level.
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Comparing the matrix lines "A" note that although the totals are not equalMR3 = MR5
=MR7 =0. A higher score does not guarantee that you can reach the highest level.
References:
1. Arnold B.F., Mathematical Statistics, Prentice-Hall, New Jersey, 1990;
2. Arnold B.F.,An approach to fuzzy hypotheses testing, Metrika, Vol. 44, 1996,pp. 119126;
3. Arnold B.F., Testing fuzzy hypotheseswith crisp data, Fuzzy Sets and Systems, Vol.
94, 1998, pp. 323-333;
4. Arnold B.F. and Gerke O., Testing fuzzy hypotheseswithin linear regression models,
Metrika, Vol. 57, 2003, pp. 81-95;
5. Casals, M.R. (1993). ―Bayesian testing of fuzzy parametric hypotheses from fuzzy
information.‖ RAIRO, Operations Research, Vol. 27, pp. 189-199.
6. Casals, M.R., Gil, M.A. and Gil, P. (1986). ―On the use of Zadeh’s probabilistic
definition for testing statistical hypotheses from fuzzy information.‖Fuzzy Sets and
Systems, Vol. 20, pp. 175-190.
7. Casals, M.R. and Gil, M.A. (1989). ―A note on the operativeness ofNeyman-Pearson
tests with fuzzy information.‖ Fuzzy Sets and Systems, Vol. 30, pp. 215-220.
8. Casella, G. and Berger, R.L. (2002). Statistical Inference. Sec. Ed.,Duxbury Press.
9. Chen,S.J. and Hwang, C.L., ―Fuzzy Multiple Attribute Decision Making‖, SpringerVerlag, NY.
10. Chen, C.C., Lai, C.M., Chen, T.H., Nien, H.Y., (2005) ―Statistical test of fuzzy
hypotheses using linguistic variable‖, Journal of Industrial and Business Management,
Vol 1, no. 1, pp 11-22.
11. Delgado M., Verdegay, M.A. and Vila, M.A. (1985). ―Testing fuzzy hypotheses: A
Bayesian approach.‖ In: Gupta, M.M. et al. (Eds.), Approximate Reasoning in Expert
Systems, North-Holland Publishing Co., Amsterdam, pp. 307-316.
12. Grzegorzewski, P. (2000). ―Testing statistical hypotheses with vague data.‖ Fuzzy
Sets and Systems, Vol. 112, pp. 501-510.
13. Kruse, R. and Meyer, K.D. (1987). Statistics with Vague Data. ReidelPub. Comp.,
Dordrecht, Netherlands.
14. Kwakernaak, H. (1978). ―Fuzzy random variables: definition and theorems‖,Inform.
Sci. Vol. 15, pp. 1-29.
15. L´opez-D´ıaz, M. and Gil, M.A. (1997). ―Constructive definitions of fuzzy random
variables.‖ Stat. Prob. Lett., Vol. 36, pp. 135-144.
16. Lehmann, E.L. (1994). Testing Statistical Hypotheses. Chapman-Hall,New York.
17. Liu, B. (2004). Uncertainty Theory: An Introduction to Its Axiomatic Foundation.
Physica-Verlag, Heidelberg.
18. Mendenhall, W., Wackerly, D.D., and Scheaffer, R.L., 1998, Mathematical Statistics
with Applications, (5thed.) PWS-KENT, Boston.
19. Montenegro, M., Casals, M.R., Lubiano, M.A. and Gil, M.A. (2001). ―Two-sample
hypothesis tests of means of a fuzzy random variable.‖ Inform.Sci., Vol. 133, pp. 89100.
20. Puri, M.L. and Ralescu D.A. (1986). ―Fuzzy random variables.‖ J. Math.Anal. Appl.,
Vol. 114, pp. 409-422.
21. Saade, J. (1994). ―Extension of fuzzy hypotheses testing with hybrid data.‖ Fuzzy Sets
and Systems, Vol. 63, pp. 57-71.
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22. Saade, J. and Schwarzlander, H. (1990). ―Fuzzy hypotheses testing with hybrid data.‖
Fuzzy Sets and Systems, Vol. 35, pp. 192-212.
23. Son, J.C., Song, I. and Kim, H.Y. (1992) ―A fuzzy decision problem based on the
generalized Neyman-Pearson criteria.‖ Fuzzy Sets and Systems, Vol.47, pp. 65-75.
24. Taheri, S.M. (2003) ―Trends in fuzzy statistics.‖ Austrian Journal ofStatistics, Vol. 32,
pp. 239-257.
25. Taheri, S.M. and Behboodian, J. (1999). ―Neyman-Pearson lemma for fuzzy
hypotheses testing.‖ Metrika, Vol. 49, pp. 3-17.
26. Watanabe, N. and Imaizumi, T. (1993). ―A fuzzy statistical test of fuzzy hypotheses.‖
Fuzzy Sets and Systems, Vol. 53, pp. 167-178.
27. Zadeh, L.A. (1968). ―Probability measures of fuzzy events.‖ J. Math.Anal. Appl., Vol.
23, pp. 421-427.
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PROPOSALS TO IMPROVE THE RELIABILITY MODELING IN THE
CASES OF TRUNCATED TESTS
PhD. lecturer eng., Jan-Cristian GRIGORE, University of Piteşti, Street Tîrgu dinVale No.1
PhD. Professor eng., Alexandru BOROIU, University of Piteşti, Street Tîrgu dinVale No.1
Andrei-Alexandru BOROIU, Polytechnica University of Bucharest
Abstract: For modeling the reliability, there are used specifically designed computing programs, two situations
being possible: complete tests and incomplete tests. However, it is found that in the cases of incomplete tests it is
not made distinguish between the censored type testing (which ends when a preset number of products of
considered batch failed) and the truncated type testing (which ends at a predetermined time moment). In the case
of the incomplete type testing, there is not taken into consideration the time interval between the moment of the
last failure and the moment of the end of the experiment (the case of truncated type testing).
Therefore, based on the realized study, there is proposed a computing algorithm for modeling the reliability
through the usual mathematical laws (Weibull, exponential, normal) when trying truncated type. The results
obtained confirm the usefulness of theoretical and practical computational algorithms proposed
Keywords : reliability modeling, computing program, censored tests, truncated tests, Weibull law, exponential
law, normal law.
1. PROBLEM FORMULATION
There are used special designed computing programs to determinate the reliability
indicators for different mathematical models. These computer programs devoted to
determining the reliability indicators for the various mathematical models.
For example, ReliaSoft Weibull ++7 [4] is a high-performance program, which, based on
number of items tracked and recorded times of failure - for some elements (if incomplete
attempts) or for all items (complete test) realize experimental distribution modeling through
various theoretical distribution laws: Weibull-2P, Weibull-3P, Normal, Lognormal, Exp-1P,
Exp-2P, G-Gamma, Gamma, Logistic, Loglogistic, Gumbel, etc.
But working with these computing programs, it was found, however, that these have some
limitations in terms of differentiating between different types of tests. Thus, next there are
presented the following research.
So, it was started from the mileages where it were broken the 10 cars, in the framework of
a complete test (the test stops after the failure of all components) – presented in Table 1.
Table 1. The values for failure times.
343
No.
Failure time [km]
1
2
3
4
5
6
7
8
9
10
24791
28427
31175
33871
35338
38033
40102
42913
45218
48203
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The experimental data are highlighted in figure 1 (the number of failed elements is F =
10, and the number of the supervised elements that were not damaged is S = 0), and the graph
Weibull-3P (the three-parametric model) which shows the values of the three parameters
(   3.0129,   25157 km;   14417 km ) is presented in figure 2.
ReliaSoft W eibull++ 7 - www.ReliaSoft.com
F/S Timeline
FS Timeline
Failure
0,000
10000,000
20000,000
30000,000
40000,000
Boroiu Alexandru
U niversity of Pitesti
21.11.2010
00:39:12
50000,000
Time, (t)
 
Fig. 1. The graph F/S Timeline for the complete test (F = 10, S = 0).
ReliaSoft W eibull++ 7 - www.ReliaSoft.com
Probability - Weibull
99,000
Probability-W eibull
D ata 1
W eibull-3P
RRX SRM MED FM
F=10/ S=0
Adj Points
U nadj Points
Adjusted Line
U nadjusted Line
90,000
U nr e li a b ility , F ( t)
50,000
10,000
5,000
Boroiu Alexandru
U niversity of Pitesti
21.11.2010
00:25:31
100000,000
1,000
10000,000
Time, (t)
 
Fig. 2. Representation Probability Weibull-3P order to fully (F = 10, S = 0).
Using the same values for the proper functioning times of the 10 transmission shafts, it
was imagined an incomplete test in which F = 10 and S = 10, but with different scenarios for
the values assigned to the 10 monitored elements which are not breaks during the experiment:
1 – it is considered censored type test (it ends with the failure of the tenth element), so
for all the 10 elements that continue to operate, there are assigned the value of the last
recorded time: ts  48203 km (figure 3 and figure 4).
2 – it is considered the truncated type test (it not ends with the failure of the tenth
element, but at a predetermined time, which is higher than the last recorded time), so for all
the 10 elements that continue to operate, there are assigned a value of the time at which the
test stops: ts  60000 km .
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ReliaSoft W eibull++ 7 - www.ReliaSoft.com
F/S Timeline
FS Timeline
Failure
Suspension
0,000
12000,000
24000,000
36000,000
48000,000
Boroiu Alexandru
U niversity of Pitesti
21.11.2010
03:16:26
60000,000
Time, (t)
 
Fig. 3. The graph F/S Timeline for the censored incomplete test (F = 10, S = 10).
ReliaSoft W eibull++ 7 - www.ReliaSoft.com
Probability - Weibull
99,000
Probability-W eibull
D ata 1
W eibull-3P
RRX SRM MED FM
F=10/ S=10
Adj Points
U nadj Points
Adjusted Line
U nadjusted Line
90,000
U nr e li a b ility , F ( t)
50,000
10,000
5,000
1,000
1000,000
10000,000
Boroiu Alexandru
U niversity of Pitesti
21.11.2010
03:07:19
100000,000
Time, (t)
 
Fig. 4. The graph Probability Weibull-3P for the censored incomplete test (F = 10, S = 10).
3 – there are imagined, also, other values for the truncation times of the experiment:
tS. It is found that for all these different scenarios there are obtained the same values for the
Weibull-3P model parameters, ie, the computing program considers all these different tests as
a censored type test (with the censoring time equal to the time at which breaks the tenth
element). Continuing the investigations, it is imagined another censored test, in which F = 10,
but S = 20 (total, 30 elements are tracked). It appears that this time it is really obtained
different values for the three Weibull parameters, so the program has discriminatory power
for censorship tests. Analyzed test data are presented in Table 2.
Table 2. Experimental data and results obtained in the framework of reliability tests.
345
No.
Test type
F
S
F+S
1
2
3
4
complete
censored
truncated
censored
10
10
10
10
0
10
10
20
10
20
20
30
The values of the Weibull 3-P model
parameters
 = 3.0129;  = 25157 km;  = 14417 km
 = 1.6984;  = 35616 km;  = 19871 km
identical with row 2 !
= 1.5497; = 49639 km; = 20429 km
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Continuing the investigations, it is imagined another censored test, in which F = 10,
but S = 20 (total, 30 elements are tracked). It appears that this time it is really obtained
different values for the three Weibull parameters, so the program has discriminatory power
for censorship tests. Analyzed test data are presented in Table 2.
It concludes that the computing program identifies correctly the complete test and the
incomplete tests of censored type, but not the incomplete tests of truncated type. As a result,
we intend to realize a research through which we provide those theoretical elements necessary
to identify an incomplete test of truncated type and for creating a suitable computing program
to model reliability based on this type of tests.
2. REALIZED RESEARCHES
To find the theoretical elements necessary for processing the data obtained through
incomplete tests of truncated type, it can be started from the most visible reliability indicator
of reliability which depends of the type of reliability test, the estimated value of mean time
between failures m [2].
• for complete tests:
F
m
t
i
(1)
1
F
• for incomplete tests of censored type:
F
mcenz 
t
i
 S  tF
1
(2)
FS
• for incomplete tests of truncated type:
F
mtr 
t
i
 S  ttr
1
(3)
FS
where:
- tF is the time corresponding to the failure of the last element in the censored test;
- ttr is the truncation time of the test.
Note that you can get an analytical relation for the estimated average for truncated test
based on estimated average mtr when mtr truncated test:
F
mtr 
t
i
 S  ttr
1
(4)
FS
This relationship will be useful to correct the media when found as a parameter in the
mathematical model, for example if an exponential model:
t

(5)
R(t )  e m
or the normal model (which has two parameters: mean m and standard deviation .
If the normal model can be corrected even the second parameter, , through a simple
relationship, derived from the "rule of 3  '
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
m  t1
3
(6)
where t1 is the time of first failure.
For Weibull law requires a more complex analysis. So, in the particular case of
modeling by law Weibull-3P, the mean time between failures value m is depending of the all
3 Weibull parameters:
1

m        1
(7)


where  represents the Euler function of first rank (Gamma type), defined through the
analytical relation:

( x )   t x 1  e t  dt
(8)
0
Since the analytic relation of this function is quite complicated, in reliability studies is
more easily to work with the function values calculated and listed in tables [1].
The indicator m is in relation to all the three Weibull parameters, so we are not
dealing with a bi-univocal relationship, deterministic, so that will be performed an analysis to
decide which of the three indicators is most appropriate to be corrected depending on the
value of m , and thus depending on the type of test.
For this, we must define the three Weibull parameters [3]:
-  is the localization parameter or parameter position, an constant that defines the
start time of the variation of reliability function R(t);
-  is the scale parameter, expresses the extension distribution on the time axis; so, if
(t –  ) is equal with  , R(t) becomes:

(9)
R(t )  e 1  e 1  0,368
scale parameter represents the time, measured from the moment  = 0, at which 63,2% of the
elements can be failed. Therefore, this parameter expresses a characteristic operating time.
-  is the shape parameter, is dimensionless and represents the parameter that
determines the shape and curves of variation for the reliability indicators.
The parameters  and  are expressed in time units and can be graphically
highlighted (figure 5).
Fig. 5. The highlighting of the parameters
347

and  on the graph R(t) in the case of Weibull law.
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As the previously revealed problem express that the program does not offer the
possibility of extending the distribution on the time scale according to the value of truncation
time (larger than the censoring time), it follows that the most suitable to be put in a
deterministic relationship with the mean time between failures m is precisely the scale
parameter  . For this, there will be processed the analytical relations for the mean in the case
of the two types of tests – the censored test (for which the program calculates the parameters
Weibull, including cenz  ) and the truncated test (which is intended to determine the
parameter tr  ):
1

mcenz     cenz    1


1

mtr     tr    1


It results the inegality:
mcenz  
 cenz

(10)
(11)
mtr  
(12)
 tr
By reducing the inequalities (2) and (3) to equalities there is obtained concrete and
satisfactory values for the means, so based on the relation (12) it can be effectively realized
the calculation for parameter tr  .
F
t
m 
tr  cenz  tr
 cenz 
mcenz  
i
 S  ttr
1
FS
F
t
i

(13)
 S  tF

FS
Thus, in the case of truncated test from the position 3 in Table 2, we obtain the
relation (13). A value according to what is expected for the truncated test: a more extended
theoretical distribution on the time axis, compared with the case of censored test.
Therefore, the Weibull model which will be used for the truncated test from the
position 3 in Table 2 will have the parameters:  = 1.6984;  = 44897 km;  = 19871 km
1
3. CONCLUSIONS
Based on the realized researches, it can be build a computing program for the case of
incomplete tests of truncated type for each of the models considered:
- exponential model - equation (4);
- normal model - relations (4) and (6);
- if the Weibull model using additional relation (13).
In the cases of other mathematical models, a similar analysis is required to create the
computing program that will complement the complex software dedicated to reliability study.
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This work was supported by CNCSIS - UEFISCDI, project number PN-II-RU
683/2010.
REFERENCES
[1] ANDREESCU, C., TEODORESCU, C., OPREAN, I.M., DRĂGAN, V., CRISTEA,
G. (1996), Aplicaţii numerice la studiul fiabilităţii automobilelor, ISBN 973-95856-0-4, Ed.
Magie, Bucureşti;
[2] BOROIU, A., Studiu în vederea unei mai bune modelări a fiabilităţii în cazul încercărilor
complete, Revista Ingineria Automobilului nr. 20, septembrie 2011, ISSN 1842-4074;
[3] BOROIU, A. (2003), Fiabilitatea autovehiculelor, Editura Universităţii din Piteşti, ISBN
973-690-167-X, 2003
[4] * * * www.reliasoft.com
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Editura “Academica Brâncuşi” , Târgu Jiu, ISSN 1844 – 640X
GROUPOIDS AND IRREVERSIBLE DISCRETE DYNAMICAL
SYSTEMS I
Mădălina Roxana BUNECI, University Constantin Brâncuşi of Târgu-Jiu, ROMÂNIA
Abstract. The purpose of this paper is to provide a formal approach based on groupoids for studying certain
discrepancies between computational output and theoretical expectations in the analysis of the orbit space
associated to an irreversible dynamical system.
Keywords: dynamical system; groupoid; equivalence relation; computational analysis of dynamical.
.
1. INTRODUCTION
The temporal evolution of a real world system can mathematically be described by a
dynamical system. Classically, the continuous-time evolution is given by an ordinary
dx
differential equation of the form
=F(x) (F satisfying the Lipschitz existence condition),
dt
where x is state-valued function. On the other hand, if time is assumed to go on continuously
but just single instances of time are taken into account, then the mathematical model is a
discrete dynamical system. The mathematical setting for a discrete-time dynamical system is a
space X and a map :XX. The space X is the phase space (the space of all possible states of
the system) and the map  defines time evolution - the change of the states over one time
step: the state xX at time t = 0 evolves into (x) at t = 1, ((x)) at t = 2, etc. Consequently,
n(x) is the state of the system at time t = n if x is the state of the system at time t = 0. Also
this type of dynamical system naturally arises when an ordinary differential equation is
integrated by an explicit numerical scheme.
There is a rich interplay between dynamical systems theory and computational
analysis of dynamical systems. In this paper we take advantage of the framework of groupoids
in order to study at a formal level the discrepancies between orbit computation using floating
point arithmetic and theoretical expectations. More precisely, we introduce a groupoid
associated to an irreversible dynamical system and to an equivalence relation on the phase
space. The study of computational output versus theoretical expectations in the analysis of the
orbit space will be replace by a comparative study of this groupoid and of the original
groupoid associated to the dynamical system as in [3] and [4].
2. GROUPOIDS ASSOCIATED TO IRREVERSIBLE DYNAMICAL
SYSTEMS
A groupoid is a set G, together with a distinguished subset G(2) GG, and two maps:
a product map (1, 2)  12 [:G(2)  G], and an inverse map   -1 [:G  G], such that the
following relations are satisfied:
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(-1)-1 = 
If (1,2)G(2) and (2,3)G(2), then (12, 3), (1,23) G(2) and (12) 3= 1(2, 3).
(, -1)G(2), and if (1, )G(2), then (1)-1 = 1.
(-1, )G(2), and if (, 1)G(2), then -1(1) = 1.
The maps r and d on G, defined by the formulae r() =-1 and d() =-1, are called the
range and the source (domain) maps. It follows easily from the definition that they have a
common image called the unit space of G, which is denoted G(0). The fibres of the range and
the source maps are denoted Gx =r-1 ({x}) and Gx =d-1 ({x}), respectively. For x and y in G(0),
(r,d)-fibre is G xy = GxGy. It is easy to see that G xx is a group, called the isotropy group at x,
and will be denoted G(x).
(1)
(2)
(3)
(4)
The relation x~y if and only if there is G such that r()=x and d() is an equivalence
relation on G(0). Its equivalence classes are called orbits. The graph of this equivalence
relation
R=(x,y) G(0)  G(0) : there is G such that r()=x and d()
can be regarded as a groupoid, under the operations:
(x,y)(y,z) = (x,z)
(x,y)-1 = (y,x)
R is called the principal groupoid associated with G. We denote by (r,d):G→R, the map
defined by
(r,d)(x)=(r(x),d(x)) for all x∈ G.
A topological groupoid consists of a groupoid G and a topology compatible with the groupoid
structure i.e. the inverse and multiplication are continuous maps (the topology on G(2) is
induced from G×G endowed with the product topology).
Notation 2.1. Let X be a topological space, : X  X a function and E be the graph
of an equivalence relation on X. Let us denote be G(X, , E) the set:
G(X, , E) ={(x,k,y)X×Z×X:
there is nZ such that n+k0 and for all mn (m+k(x), m(y))E },
where Z is the group of integers.
We endow G(X, , E) with the subspace topology coming from XZX, where Z has
the discrete topology. Under the operations
(x, n, y)(y, m, z) = (x, n+m, y)
(x, n, y)-1 = (y, -n, x)
XZX is a topological groupoid. In the following the unit space of the groupoid XZX
{(x,0,x), xX}
will be identified with X.
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Proposition 2.2. Let : X  X be a function, E be the graph of an equivalence
relation on X and
G(X, , E) ={(x,k,y)X×Z×X:
there is nZ such that n+k0 and for all mn (m+k(x), m(y))E }.
Then
1. G(X, , E) is a subgroupoid of XZX having the same unit space.
2. If X is a topological space and G(X, , E) is endowed with the induced topology from
X×Z×X, then G(X, , E) is a topological groupoid.
Proof. If (x, k1, y), (y, k2, z)  G(X, , E), then there are n1 and n2 such that n1+k1 0,
n2+k2 0, and for all m max(n1-k2, n2),

m k 2  k1
x , mk 2 yE and

m k 2
y, m z E.
Consequently, if n0 = max(n1-k2, n2), n0+k2+k1n1 + k10 and for every mn0,
x , m z E. Hence (x, k1+k2, z) G(X, , E). If (x,k,y) G(X, , E), then there is

nZ such that n+k0 and for all mn (m+k(x), m(y))E. Let n1=max(n+k,k). Then n1-k0
and for all mn1 we have  mk k x ,  mk y E and consequently,  mk y,  m x  E.
Thus (y,-k,x) G(X, , E).

m k 2  k1





Examples 2.3.
1. Let fl(x) denote the floating point number approximating x and let : R  R be a
function. Let us define an equivalence relation E on R:
y1 ~ y2 if and only if fl(y1) = fl(y2) or
there are x1, x2 such that fl(x1) = fl(x2), fl((x1)) = fl(y1) fl((x2))=fl(y2).
Then (x, fl(x)), ((fl(x)), (x))E and (fl((fl(x))), (x))E for all x.
The study of computational output versus theoretical expectations in the analysis of the orbit
space could be replace by a comparative study of the groupoid G(X, , E) and of the groupoid
G(X, ) ={(x,k,y)X×Z×X: there is nZ such that n+k0 m+k(x) = m(y)} introduced in [3]
(let us notice that if * is an approximation for  such that fl((fl(x)))=fl(*(fl(x)) for all x,
then (n(x), *n(fl(x))E for all x and all nZ, n1).
2. To study a long term dynamical behavior of a discrete dynamical system (X, ) we
can use the groupoid G(X, , E) where E is defined bellow assuming that the phase space is
endowed with a uniform structure US:
x ~ y if and only if
for each VUS there is nVZ, nV0 such that (m(x), m(y))V for all mnV.
If (X, d) is a metric space and US is the uniform structure associated to the metric then
x ~ y if and only if limnd(n(x),n(y))=0.
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3. If the space X is endowed with a uniform structure US and E={V, VUS} then
G(X,,E) and the groupoid G(X, P, H, , US) introduced in [2] coincide (where
xn=(x,n)=n(x), P=N, H=Z).
4. If E = Δ = { (x, x) : x X }, :XX, then G(X,,E)= G(X, ) (the groupoid
introduced in [3]).
Notation 2.4. Let : X  X be a function, E be the graph of an equivalence
relation on X and
G(X, , E) ={(x,k,y)X×Z×X:
there is nZ such that n+k0 and for all mn (m+k(x), m(y))E }.
For each xX, let us denote by
H xx ={k  Z: there is nZ such that n+k0 and for all mn (m+k(x), m(x))E }
Let kx be the smallest positive k H xx if such k exists, and kx=0 otherwise.
The next propositions will be used to characterize the transported topology (introduced
in [1]) from G(X,,E) to its principal groupoid.
Proposition 2.5. With the notation 2.4, for every x,yX, let
G xy ={ G(X, , E): r()=x and d()=y}.
(we identified the unit space of G(X, , E) with X). Then
1. For every xX, G xx =(x, kxt, x): tZ}.
2. For every G(X, , E), kr() = kd().
3. For every G(X, , E) with the property that kr() = 0 (and consequently, kd()=0),
there is a unique kr(),d()Z such that
G dr  =(r(), kr(),d(), d()).
Moreover kd(),r() = - kr(),d().
4. For every G(X, , E) with the property that kr()  0, there is k0 such that
(r(),k,d()) G dr 
Proof. For each xX,
G xx ={(x, k, x)  X  Z  X :
there is nZ such that n+k0 and for all mn (m+k(x), m(x))E }
={(x, k, x)  X  Z  X : k H xx }
={x}× H xx ×{x}, is the isotropy group at x associated to the groupoid G(X, , E).
Since H xx is a subgroup of Z, it follows that there is an integer kx0 such that H xx =kxZ (kx = 0
iff H xx ={0} and kx is the smallest positive k H xx otherwise). Thus G xx =(x, kxt, x): tZ}.
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For every G(X, , E), H rr   and H dd   are isomorphic. Consequently, kr() = kd().
Let G(X, , E) be such that kr() = 0. Let us assume by contradiction that there are
k1≠k2 such that 1=(r(), k1, d()) G dr  and 2=(r(), k2, d()) G dr  . Then
(r(), k1- k2 ,r()) = 12-1 G rr   ={(r(),0,r())}.
Hence k1 – k2 = 0, which is in contradiction with k1≠k2. Consequently, there is a unique
kr(),d()Z such that
G dr  =(r(), kr(),d(), d()).

Obviously, G dr = G dr 

1
=(d(), -kr(),d(), r()).
Let G(X, , E) be such that kr() ≠ 0. Then there is mZ such that
(r(),m,d()) G dr  . Let tZ, t0 be such that m+tkr() 0. It is easy to see that
(r(),k+tkr(),d()) G dr  .
Notation 2.6. With the notation 2.4, for every x,yX, let
G xy ={ G(X, , E): r()=x and d()=y}.
and let G(X, , E). If kr() = 0 (and consequently, kd()=0), let us denote by kr(),d() the
unique kZ such that
G dr  =(r(), k, d()).
If kr() ≠ 0 let us denote by kr(),d() the smallest nonnegative number k with the
property that (r(), k, d()) G dr  .
(
k x m
For each x, let nx be the smallest nonnegative integer n, n+kx0 satisfying
x  ,m(x))E for all mn.
For every equivalent units x,yX, let nx,y be the smallest nonnegative integer n
satisfying ( 
k x , y m
x  ,m(y))E, for all mn.
Proposition 2.7. With the notations 2.4 and 2.6, we have
1. If G(X, , E) and kr()  0, then
G dr  =(r(), kr(),d() + kr() t, d()), tZ.
2. If G(X, , E), kr()  0, then kr(),d()  {0,1, …, kr()-1}.
3. If G(X, , E), then kr(),d()=0 <=> kd(),r()=0 <=> there is nN such that for all mn
(m(r()), m(d()))E.
4. If G(X, , E) and kr(),d()≠0, then kd(),r() = kr() - kr(),d().
5. For every equivalent units x,yX with the property that kx0, we have
nx,y < kx+max(nx,ny).
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Proof. Let G(X, , E) be such that kr() ≠ 0. Let k1 Z and let k0 be the remainder
obtained by Division Theorem : k1 = kr() t+ k0. Then
0 =(r(), k0, d()) G dr  if and only if 1 =(r(), k1, d()) G dr  .
Since kr() is the smallest positive k with the property that (r(),k,r()) G rr   , it follows that k0
is the smallest nonnegative number k having the property that =(r(), k, d()) G dr  . Thus k0
= kr(),d(). Therefore 1 =(r(), k1, d()) G dr  if and only if there is tZ such that k1 = kr() t +
kr(),d(). Since kr(),d(). is the remainder, obviously, kr(),d()  {0,1, …, kr()-1}.
Moreover k1 = kr() t+ kr(),d() implies - k1 = kr() (-t-1)+ kr() - kr(),d() = kd() (-t-1)+ kr()
- kr(),d(). If kr(),d()  0, then 0  kr() - kr(),d() < kr() = kd(). Thus kr() - kr(),d() is the remainder
of the division of –k1 by kd(). On the other hand
1 =(r(), k1, d()) G dr  if and only if 1-1 =(d(), -k1, r()) G dr .
Consequently, kd(),r() = kr() - kr(),d().
Let us consider two equivalent units x,yX such that kx≠0. Let us assume by
contradiction that nx,y  kx+max(nx,ny). Hence nx,y – 1  max(nx,ny). Since for all n 
max(nx,ny),
(
k x ,y n
x  ,  k x ,y k x n x  )E,
(  k x n y  ,  n y  )E,
it follows that for all m  nx,y – 1,
(
k x , y m
x  , k x ,y k x m x  )E,
(  k x m y  ,  m y  )E.
On the other hand for all m  nx,y – 1, kx + m  nx,y and therefore
(
k x , y k x m
x  ,  k x m y )E.
Consequently, (  x , y x  ,  m y  )E for all m  nx,y – 1, which is in contradiction with the
choice of nx,y. Thus nx,y < kx+max(nx,ny).
k
m
BIBLIOGRAPHY
[1] M. Buneci, Topological groupoids with locally compact fibres, Topology Proceedings 37
(2011), 239-258.
[2] M. Buneci şi I. C. Bărbăcioru, Groupoids and uniformities associated to irreversible
dynamical systems, Fiabilitate şi durabilitate (Fiability & durability), No. 2(8)/2011, 103-106.
[3] R. Exel and J. Renault, Semigroups of local homeomorphisms and interaction groups,
Ergodic Theory Dynam. Systems 27 (2007), no. 6, 1737--1771.
[4] J. Renault, Cuntz-like algebras, in Operator theoretical methods (Timişoara, 1998), 371386, Theta Found., Bucharest, 2000.
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Editura “Academica Brâncuşi” , Târgu Jiu, ISSN 1844 – 640X
GROUPOIDS AND IRREVERSIBLE DISCRETE DYNAMICAL
SYSTEMS II
Mădălina Roxana Buneci, University Constantin Brâncuşi of Târgu-Jiu, ROMÂNIA
Abstract. The purpose of this paper is to study the topology of the orbit space of an irreversible
discrete dynamical system (X, ) seen as a principal groupoid associated to the groupoid G(X, ,E) introduced in
[1] (where E is an equivalence relation on X).
Keywords: dynamical system; groupoid; equivalence relation; topology.
.
1. INTRODUCTION
We use the same notation and definitions as in [1]. The principal groupoid R
associated with a groupoid G can be endowed with various topologies such as product
topology [6] (the subspace topology on R induced from G(0)  G(0), where G(0) is endowed
itself with the subspace topology coming from G) or quotient topology [6] (the finest
topology on R with the property that (r,d):G→R is continuous). However under these
topologies the fibres of R fail to have certain topological properties that the fibres of G had
and in many cases the topological properties of fibres (endowed the subspace topology) are
more important than the properties of the space. In [2] we introduced a topology on R such
that the maps dx : Gx  Rx are continuous open maps, where dx is defined by dx() = d() for
all G, so certain properties of Gx are transported on Rx. We called that topology the
transported topology from G. The transported topology from G on R is finer than the quotient
topology on R which is finer than the product topology on R. The purpose of this paper is to
characterize the transported topology for the groupoid G(X,,E) introduced in [1].
2. THE PRINCIPAL GROUPOID ASSOCIATED TO G(X,,E)
Proposition 2.1. Let X be a locally compact space, : X  X a function and E be the
graph of an equivalence relation on X satisfying the condition that for each net (x i)iI in X
converging to xX, there is i0I and m0Z, m00 such that (m(xi), m(x))E for all ii0 and
all mm0. Then
G(X, , E) ={(x,k,y)X×Z×X:
there is nZ such that n+k0 and for all mn (m+k(x), m(y))E }
endowed with the subspace topology coming from XZX, where Z has the discrete
topology, is a topological locally compact groupoid under the operations
(x, n, y)(y, m, z) = (x, n+m, y)
(x, n, y)-1 = (y, -n, x)
Proof. We proved in [1] G(X, , E) is a topological groupoid. Let (x,k,y) G(X, ,
E), Ax be a compact neighborhood of x and By be a compact neighborhood of y. Let us prove
that (Ax  {k}  By)  G(X, , E) is a compact neighborhood of (x,k,y). Let (xi, k, yi)iI be a
net in (Ax  {k}  By)  G(X, , E). Since Ax (respectively, By) is compact there is a subnet
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of (xi)i (respectively, (yi)i), also denoted (xi)i (respectively, (yi)i), converging to aAx,
(respectively, bBy). Let us show that (a,k,b) G(X, , E). Let m00 and i0I be such that
m0+k0 and (m+k(xi), m+k(a), (m(yi), m(b)E for all ii0 and all mm0. Since (xi, k, yi)
G(X, , E), it follows that there is ni Z such that ni+k0 and for all mni,
(m+k(xi),m(yi))E. Let n0 = max(ni0, m0). Then for all mn0,
(m+k(a), m(b))= (m+k(xi), m+k(a)) (m+k(xi), m(yi)) (m(yi), m(b))E.
Thus (a,k,b) G(X, , E), and therefore (Ax  {k}  By)  G(X, , E) is compact.
Notation 2.2. Let X be a topological space, : X  X a function and E be the graph
of an equivalence relation on X. The principal groupoid associated to
G(X, , E) ={(x,k,y)X×Z×X:
there is nZ such that n+k0 and for all mn (m+k(x), m(y))E }
is R(X, , E)=(x,y)XX:
there are n, k Z such that n+k0 and for all mn (m+k(x), m(y))E}.
Let us denote with G the subspace topology on G(X, , E) coming from XZX,
where Z has the discrete topology.
Let us denote with R the topology on R(X, , E) transported topology from G(X, ,
E) (defined in [2]). Let us recall that a basis for the topology R is given by the family of sets
{U(F)}F, where each F is a finite collection F of open subsets of G(X, , E) (i.e. F  G) and
U(F) =
 r, d U 
UF
=  {(x,y): there is kZ such that (x,k,y)U}.
UF
Let us denote by X the topology on X, and let us notice that X coincides with the
topology on X seen as unit space of G(X, , E) (under the identification x  (x,0x))
Let us denote by X(R) the topology on X seen as unit space of G(X, , E) (under the
identification x  (x,x)). The topology X(R) is finer that X [2].
Proposition 2.3. Let X be a topological space, : X  X a function and E be the
graph of an equivalence relation on X. With the notations 2.4, 2.5 [1] and 2.2, if (xi)iI is a net
in X and xX such that kx  0, then the following conditions are equivalent:
i)
ii)
(xi)iI converges to x with respect to X(R).
(xi)iI converges to x with respect to X and there is i0 such that for all ii0,
kxi0 and kxi | kx (kxi divides kx)
Proof. (xi)iI converges to x with respect to X(R) if and only if (xi,x i)(x,x) with
respect to R. Furthermore (xi,x i)(x,x) with respect to R if and only if for every  in
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
G(X,,E) with r()=x and d()=y and every subnet x i j , x i j
x
i jk

, xij
k k
d(k)= x i j
k

j
of (xi,xi)i there is a subnet
with the property that there are there are k G(X, , E) with r(k)= x i j and
k
such that k . Thus the following conditions are equivalent
a. (xi,x i)(x,x) with respect to R
b. (xi)iI converges to x with respect to X and for every k such that (x, k, x)
G(X,,E), there is ik such that for all i  ik (xi, k, xi) ) G(X,,E).
Let k=kx (obviously, (x,kx,y)G(X,,E)). Moreover (xi, kx, yi) ) G(X,,E) if and
only if there is an integer ti such that kx=tikxi. Thus if (xi,kx,yi) ) G(X,,E), then kxi0 and
kxi | kx. Conversely, let us assume that there is an integer ti such that kx=tikxi and let k such that
(x, k, y) G(X,,E). Then there is an integer t such that k=tkx. Hence k=ttikxi and therefore
(xi, k, yi) ) G(X,,E).
Proposition 2.4. Let X be a topological space, : X  X a function and E be the
graph of an equivalence relation on X. With the notations 2.4, 2.6 [1] and 2.2, if (xi)iI is a net
in X and xX such that kx  0, then the following conditions are equivalent:
i)
(xi)iI converges to x with respect to X(R).
ii)
(xi)iI converges to x with respect to X
Proof. As in the proof of the preceding proposition, (xi)iI converges to x in X(R) if
and (xi)iI converges to x in X and for all k with the property that (x, k, x) G(X,,E), there
is ik such that for all i  ik (xi, k, xi) ) G(X,,E). If kx=0 and (x, k, x) G(X,,E), then k=0.
Since (xi,0,xi)G(X,,E) for all iI, it follows that (xi)iI converges to x in X(R).
Proposition 2.4. Let X be a topological space, : X  X a function and E be the
graph of an equivalence relation on X. With the notations 2.4, 2.6 [1] and 2.2, if (xi,yi)iI is a
net in R(X,,E) and (x,y) R(X,,E) such that kx  0, then the following conditions are
equivalent:
(xi,yi)iI (xi)iI converges to to (x,y) with respect to R.
(xi)iI converges to x with respect to X, (yi)iI converges to y with respect to X
and there is i0 such that for all ii0,
k x i 0, kxi | kx (kxi divides kx) and kxi | kx,y – k x i , yi
i)
ii)
Proof. (xi,yi)iI (xi)iI converges to to (x,y) with respect to R if and only if for every 
in G(X,,E) with r()=x and d()=y and every subnet x i j , y i j of (xi,yi)i there is a subnet
x
i jk
, yi j

k k


j
with the property that there are there are k G(X, , E) with r(k)= x i j and
k
d(k)= y i j such that k  [2].
k
i) => ii) If (xi,yi)i is a net in R(X, , E) and if (xi,yi)(x,y) with respect to R, then
r(xi,yi)r(x,y)=x and d(xi,yi)d(x,y)=y with respect to X(R). Hence there is i1 such that for
all ii1, kxi0, kxi | kx (kxi divides kx). If =(x, kx,y, y), then   G(X,,E), r()=x and d()=y.
Thus there is i2 such that for all ii2, (xi, kx,y, yi)  G(X,,E). Hence there is tiZ such that
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kx,y= k x i , yi +ti k x i .
Therefore k x i | kx,y – k x i , yi .
ii)=>i) It can be easily prove that ii) and (x, k, y) G(X,,E) imply (xi, k, yi)
G(X,,E), for large enough i.
Proposition 2.5 Let X be a topological space, : X  X a function and E be the graph
of an equivalence relation on X. With the notations 2.4, 2.6 [1] and 2.8, if (xi,yi)iI is a net in
R(X,,E) and (x,y) R(X,,E) such that kx = 0, then the following conditions are equivalent:
i)
ii)
(xi,yi)iI (xi)iI converges to to (x,y) in R(X,,E).
(xi)iI converges to x with respect to X, (yi)iI converges to y in X, there is i0
such that for all ii0,
( k x i =0 and k x i , yi =kx,y)or ( k x i 0 and k x i | kx,y – k x i , yi )
Proof. i)=>ii) If (xi,yi)i is a net in R(X, , E) and if (xi,yi)(x,y) with respect to R,
then r(xi,yi)r(x,y)=x and d(xi,yi)d(x,y)=y with respect to X(R) and consequently with
respect to X. If =(x, kx,y, y), then   G(X,,E), r()=x and d()=y. Thus there is i2 such that
for all ii2, (xi, kx,y, yi)  G(X,,E). Hence there is tiZ such that
kx,y= k x i , yi +ti k x i .
Therefore if k x i 0, k x i | kx,y – k x i , yi . If k x i =0, then k x i , yi =kx,y.
ii)=>i) It can be easily prove that ii) and (x, k, y) G(X,,E) imply (xi, k, yi)
G(X,,E), for large enough i.
BIBLIOGRAPHY
[1] M. Buneci, Groupoids and irreversible dynamical systems I, 5th Symposium Durability
and Reliability of Mechanical Systems SYMECH 2012, Târgu-Jiu, mai 2012.
[2] M. Buneci, Topological groupoids with locally compact fibres, Topology Proceedings 37
(2011), 239-258.
[3] M. Buneci şi I. C. Bărbăcioru, Groupoids and uniformities associated to irreversible
dynamical systems, Fiabilitate şi durabilitate (Fiability & durability), No. 2(8)/2011, 103-106.
[4] R. Exel and J. Renault, Semigroups of local homeomorphisms and interaction groups,
Ergodic Theory Dynam. Systems 27 (2007), no. 6, 1737--1771.
[5] J. Renault, Cuntz-like algebras, in Operator theoretical methods (Timişoara, 1998), 371386, Theta Found., Bucharest, 2000.
[6] J. Renault, The ideal structure of groupoid crossed product algebras, J. Operator Theory,
25 (1991), 3-36.
359
Fiabilitate si Durabilitate - Fiability & Durability Supplement no 1/ 2012
Editura “Academica Brâncuşi” , Târgu Jiu, ISSN 1844 – 640X
THE CALCULATION METHOD FOR SPHERICAL OPERATORS
IN MALKIN'S MODEL
Constantin Cristinel GIRDU, School Inspectorate Gorj, Tg-Jiu,
[email protected]
Abstract: The model was introduced by Malkin (ECM) to describe the behavior of rare earth metals (RE) and
transition metals (TM) used as an impurity ion crystal field of ligands belonging to the crystal (host matrix).The
calculation is quite easy for those who apply irreducible tensor operators MAPLE programming introduced by
Malkin.
Keywords: Malkin's model, load sharing model, ECM, single particle operators.
Introduction: For this model crystal field Hamiltonian (Hamiltonian of interaction between
2l
ligand field and impurity ions) is calculated according to the relation: H cr  
p
B O
p 0 k   p
k
p
k
p
(1.1)
where B pk are crystal field parameters of the ligand and are calculated as a sum of two
contributions:
B pk  B pk ,q  B pk ,s
(1.2)
V pk  i , i 
k
k 2
p
B p ,q   K p e r  qi
(1.3)
Rip 1
i
B pk , s  K pk e 2
k
22 p  1
2
2
2 V p  i , i 






G
S
i

G
S
i


G
S
i
i s s
 
p  
5
Rip 1


(1.4)
Irreducible tensor operators O pk introduced by Malkin acting on angular parts of wave
functions ψ and are single particle operators.
1 k
k
Op 
Zp ,
(1.5)
a pk
where a pk sunt factori numerici tabelaţi, and
Z
K
p
is calculated using the harmonic formula:
C p k   1k C pk , k  0



K
 k

C
,
k

0
 (1.6)
Zp  p


k
k
k
 i C p   1 C p , k 0
Irreducible tensor operators O pk are calculated on the basis of spherical single particle
operators play by the following relation:
4
C qk  
Y pk
(1.7)
2k  1
where Y pk spherical harmonics are calculated by Malkin's model with its annexes.

360

Fiabilitate si Durabilitate - Fiability & Durability Supplement no 1/ 2012
Editura “Academica Brâncuşi” , Târgu Jiu, ISSN 1844 – 640X
Analysis model: Calculation of spherical harmonic functions
> # Calculation of the table of coefficients angular coordinates (alpha,beta,gamma1) I took
a[i] vector line format i no Ri(last item on the line i table) then put b[i] then transposed
alpha[i]:=a[i].E1/(a[i].b[i]);beta[i]:=a[i].E2/(a[i].b[i]);
gamma1[i]:=a[i].E3/(a[i].b[i]);where
E1:=<1,0,0>:E2:=<0,1,0>:E3:=<0,0,1>: I copied the line copies i table and put the program. I
made 45 copies linii.merge repede.se line i is put in front a[i]:=< line elements i cu | between
components >: then put b[i]:=< line elements i with , between components >: and still put in
the table below. for n put how many lines are. When working with the other program is
adding to S:=sum(F(i),i=1..n);
> with(LinearAlgebra):
> E1:=<1,0,0>:E2:=<0,1,0>:E3:=<0,0,1>:
> n:=45;
>a:=array(0..n):b:=array(0..n):x:=array(0..n):x:=array(0..n):x:=array(0..n): a[1]:=<-1.9985e05|-2.0507|1.9985e-05>:b[1]:=<-1.9985e-05,-2.0507,1.9985e-05>:
a[2]:=<-1.9985e05|2.9913e-05|-2.0507>:b[2]:=<-1.9985e-05,2.9913e-05,-2.0507>:
a[3]:=<2.0507|2.9913e05|1.9985e-05>:b[3]:=<2.0507,2.9913e-05,1.9985e-05>: a[4]:=<-1.9985e-05|2.0508|1.9985e05>:b[4]:=<-1.9985e-05,2.0508,1.9985e-05
>:
a[5]:=<-2.0508|2.9913e-05|1.9985e05>:b[5]:=<-2.0508,2.9913e-05,1.9985e-05>:
a[6]:=<-1.9985e-05|2.9913e05|2.0508>:b[6]:=<-1.9985e-05,2.9913e-05,2.0508>:
a[7]:=<2.0507|-2.0507|1.9985e05>:b[7]:=<2.0507,-2.0507,1.9985e-05>:
a[8]:=<-1.9985e-05|-2.0507|-2.0507>:b[8]:=<1.9985e-05,-2.0507,-2.0507>:
a[9]:=<2.0507|2.9913e-05|-2.0507>:b[9]:=<2.0507,2.9913e-05,-2.0507>:
a[10]:=<-2.0508|2.0508|1.9985e-05>:b[10]:=<-2.0508,2.0508,1.9985e-05>:
a[11]:=<-1.9985e-05|2.0508|2.0508>:b[11]:=<-1.9985e-05,2.0508,2.0508>:
a[12]:=<2.0508|2.9913e-05|2.0508>:b[12]:=<-2.0508,2.9913e-05,2.0508>:
a[13]:=<-1.0254|-3.0761|1.0254>:b[13]:=<-1.0254,-3.0761,1.0254>:
a[14]:=<-1.0254|1.0254|-3.0761>:b[14]:=<-1.0254,1.0254,-3.0761>:
a[15]:=<3.0761|1.0254|1.0254>:b[15]:=<3.0761,1.0254,1.0254>:
Results and discussion:
V pk - depend on the spherical coordinates of the crystal lattice doped with impurity ions.
Vpk - are polynomials that depend spherical spherical coordinates θi si υi of ligands.
According to Cartesian coordinates x, y, z  and angular  ,  ,   we have the following
relations:   x / r,   y / r,   z / r
In the calculation of V pk , we have:  
x
y
z
,   ,   , where r  x 2  y 2  z 2
r
r
r
Spherical harmonics are defined by the (1.8), with V→Y
Yl m   1  lm  2 
q
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1 / 2
 e im
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Associated polynomials are defined by functions  lm :
1/ 2
 00  1 / 2 
10  3 / 2
 cos 
1/ 2
  3 / 4
 sin 
 02  5 / 8
 3 cos 2   1
1
1
1/ 2

1/ 2
12  15 / 4
 22  15 / 16 
 sin 2 
1/ 2

 30  7 / 8

 sin  cos 
1/ 2
 5 cos 3   3 cos 
1/ 2

13  21 / 32 

 sin   5 cos 2   1
1/ 2
  105 / 16 
1/ 2
2
3

 sin  cos 
2
 33  35 / 32 
 sin 3 
 04  9 / 128
 35 cos 4   30 cos 2   3
1/ 2


 45 / 32   sin   7 cos   3 cos  
 45 / 64   sin   7 cos   1
1/ 2
14
 24
1/ 2
3
1/ 2
 34  315 / 32 
1/ 2
 44  315 / 256 
2
2
 sin 3   cos 
1/ 2
 sin 4 
Conclusions:
Spherical tensor operators were refined using the computer program MAPLE.
Experimental and theoretical energy levels are calculated based on crystal field parameters
determined and the spherical tensor operators and investigated the energy levels are well
described by crystal field.
References:
1. Călin N. Avram – Vibronic laser LiCaAlF6 :Cr3+, Publishing Mirton, Timisoara
2004.
2. Nicolae M. Avram – Energy levels of ions in crystals, Publishing Mirton,
Timisoara 2001.
3. Gîrdu Constantin Cristinel - Report no. 3, West University of Timisoara.
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NUMERICAL APPLICATIONS ON RIGID SOLID CALCULATION
USING LINEAR ELASTIC METHOD
PhD. lecturer eng., Jan-Cristian GRIGORE, University of Piteşti, Street Tîrgu dinVale No.1
Abstract: Rigid solid model without constraints, suspended elastic is used in a number of technical
achievements such as heat engines, devices for measuring the elastic guides, compliance mechanisms of
industrial robots etc. During operation, geometric constraints may appear to limit the number of degrees of
freedom of rigid. In this paper, using the relative displacements, the general theory to expose such cases, to
customize the flat state, is made general algorithm computing and numerical applications are
Keywords : Rigid constraints, relative, linear elastic calculation, clearances.
1.INTRODUCTION
Rigid solid model without constraints, suspended elastic is used in a number of
technical achievements cumsunt: heat engines, measuring instruments with guides elastic
compliance mechanisms of industrial robots, was ndaţiile morning, etc. During their operation
may occur geometric constraints that limit the number of degrees of freedom of rigid.
The paper using relative movement [5] exhibit the general theory for such cases, the
calculation algorithm is drawn up and is a numerical application.
2.CONSTRAINTS (LINKS, JOINTS)
Free rigid solid has six degrees of freedom and rigid solid number k two constraints
(single) has n  6  k degrees of freedom.
Constraints is achieved through physical contact (permanently) with other bodies.
Two rigid solid contact is achieved by kinematic joints.
There is a joint reaction (force) and displacements (infinitesimal) possible.
It can be defined [6], a local reference system, the matrices ui , si  respectively.
Figure 1. Kinematic coupling
Thus the kinematic coupling of Figure 1 cylinder, the solid rigid has restrictions
(reaction) on the directions of axes Ox, Oy and rotation restrictions (moments) axes Ox, Oy ,
we obtain, for restrictions column matrices
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u1  1
u3  0
0 0 0 0 0 ; u2   0 1 0 0 0 0
T
T
0 0 1 0 0 ; u4   0 0 0 0 1 0
and column matrix of the torsor of the reaction can be written as
T
T
(1)
4
 f R    i ui 
(2)
i 1
i , i  1,2,3,4 are the real parameters.
Relationship (2) can be written in the form,
 f R   u 
where u  , matrix restrictions and  , matrix scalars restrictions, and the relations
u  u1 u2  u3 u4  ;   1
(3)
(4)
2 3 4 
Similarly there is the possibility of moving the axis Oz and on the same axis of
rotation Oz , leading to possible movements of the column matrices
(5)
s1  0 0 1 0 0 0T ; s2   0 0 0 0 0 1T
and such movement   vector components of kinematic couplings  , be written as
  s
(6)
where s  , matrix and matrix movements   matrix scalars movements are given by relations
 1,  2 being real parameters
s  s1 s1 ;   1
T
2 
T
(7)
It is easily verified that the matrices u , s satisfying equality
sT u  0 ; uT s  0
(8)
To pass to the reference system Oo XYZ (fig.1) considered notations;
- ( X 0 , Y0 , Z 0 ) point coordinates O in system Oo XYZ
- aij bij cij  the director cosines of axes Ox, Oy, Oz relative to the system Oo XYZ
-
R, G rotation matrix, respectively the translation
 a11
R  a21
a31
-
-
a12
a22
a32
a13 
 0
a23  ; G    Z 0
 Y0
a33 
 Z0
0
X0
Y0 
 X 0 
0 
T , T~, transformation matrices that forces movements
R 0 ~ R GR
T   
 ; T    0 R 
G R R


1 ~ 1
T  , T  , inverse matrices
T
T
T
 RT

0  ~ 1 R G  R 
1
T    T T
; T   
T
RT 
G  R R 
 0
FR ,  column matrix of the reaction torsor, respectively
(9)
(10)
(11)
torsorului movements,
expressed in matrix system Oo XYZ
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-
U , S  , restriction matrix, the matrix that possible movements, expressed in matrix
system Oo XYZ
With these notations, we obtain relations;
FR   T  f r  ;   T~ 

and inequalities
(12)
U   T u ; S   T~s
(13)
U T S   0 ;S T U   0
FR   U  ;   S 
(14)
(15)
3.STIFFNESS MATRIX SYSTEM
It considers bar AB constant section and length l (fig.2), reported to the local reference
system Axyz central principal axes of inertia of the normal section A .
Figure 2. Bar
AB constant section A and length l
Using notations;
- A, I y , I z , area that the main moments of inertia of the normal section;
- I x moment of inertia corresponding to conventional turning;
- E, G longitudinal modulus of elasticity, respectively cross;
- k1 , k 2 , k3 , k 4 elastic constants defined by relations;
EI
EA
EI
GI
(16)
k1 
, k2  3 z , k3  3 y , k4  x
l
l
l
l
-.  A ,  B , movements sections of arrays A and B ( in system Axyz );
-  f A ,  f B  torsor matrices of the efforts at sections A and B (in system Axyz ),
obtain [6] stiffness matrix in local system
0
0
0
0
0 
k1
 0 12k
0
0
0
6k2l 
2

0
0
12k3 0  6k3l
0 
k AB   
(17)

0
0
k4
0
0 
0
0
0
 6k3l 0 4k3l 2
0 


0
0
0
4k2l 2 
 0 6k2l
and then relations
f A  f B   0
(18)
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 f A  k AB  AB 
(19)
where  AB  is the relative displacement
 AB    A B 
(20)
If you go to a general reference, and notation is made
1
(21)
K AB   TAB k AB  T~AB
~
where TAB , TAB are transformation matrices, the relationship type (10), (11), obtain equality
FA   K AB  AB 
(22)
 
 
Figure 3.
If a rigid solid (Fig. 3) is suspended by more bars AB embedded points A, B and is
denoted  rigid displacement expressed in system O0 XYZ then  A    şi  B   0
relationship (22) becomes
Considering that the rigid torsor of forces acting O0 by matrix F  then the equation
of equilibrium
 FA   F   0 obtain equality
where
F   K 
(23)
K   K AB 
(24)
is system stiffness matrix.
4.CALCULULATION OF THE REACTION
DISPLAMENTS IN THE KINEMATIC LINKS
TORSOR
AND
OF
THE
For solid rigid constraints, noting with FR  the reaction torsor matrix and F  torsor
matrix of the given forces, we obtain the equilibrium equation
FR  F   K 
(25)
and how
FR   U  ;   S 
(26)
obtain the equations
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U  F K S 
(27)
in which the relations (14) to obtain equal
  S T K S  S T  F  ;   U T K 1U  U T  K 1F 
1
1
and then (26) the reactions and movements are derived
Forces of bars, local reference systems are
 f A  TAB 1K AB S 
and reaction forces and movements are derived from relationships (26)
(28)
(29)
5.APPLICATION
A parallelepiped A1 A2 A3 A4 A5 A6 A7 A8 (fig. 4.) by size 2a, 2b, 2c, suspended by bars
Ai Bi , i  1, 2 ,3 ,4, with length l and diameter d , power driven F along axis O0Y , is leaning
in point A5 a plane rigid equation X  Y  Z  a  b  c  0
Figure 3. Parallelepiped
A1 A2 A3 A4 A5 A6 A7 A8
To determine:
- reaction of point parameters A5
- forces and moments acting on points Ai , i  1, 2 ,3 ,4, concerning Ai Bi
Numerical data are: a=b=0.3 m, c=0.2 m, l=1 m, , E=2·1011N·m-2, G=0.8·1011N·m-2,
F=4000N, bars being equal to the square with e=0.028 m
Choose the reference system O0 XYZ so that its axes are axes of symmetry of the local
system is chosen rectangular A5 xyz axis so A5 z boundary plane is normal and the axis A5 x
parallel to the plane O0YZ .
Under these conditions result
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 0 2
1 
R   3 1
6
 3 1
1
0

2
0

c
b


0

1 



2  ; G  
c
0

a
;
s



6
0

 b 1
2
0 
0

0
0
1
0
0
0
0
0
0
0
1
0
0
0
0
0
0
1
0
0
0
0
0
 

0
 ; u   1
0
 
0

0
 0 

1
(30)
To calculate the stiffness matrices are chosen local reference systems Ai xi yi zi so that
the axes Ai xi axis coincides with Ai Bi (fig. 4) and axes Ai zi are parallel to the axis O0 Z and
results:
e4
EA
EI
2GI
Ai  A  e 2 , I iy  I iz  I  , I ix  2 I , k i1  k1 
, ki 2  ki 3  k 2  3 , ki 4  k 4 
12
l
l
l
ai  a ; b1  b2  b3  b4  b ; c1  c2  c3  c4  c
  1 0 0
 0  ci bi 


Ri   R0    0  1 0 ; G    ci 0  ai 
0 1
0 
 0
 bi ai
Numerical results are obtained;
  3351 N, 1  0.00268 mm, 2  0 mm, 3  0 mm, 4  0.0007 mm, 5  0.00044 mm
and the components in the local systems of the efforts torsors at the points A1 , A2 , A3 , A4 are:
f ix
f iy
f iz
mix
miy
miz
-322,021
-3066,33 1292,157
4036,47 N
-564,261 -564,261 -465,603 -465,603 N
-559,061 -411,074 -411,074 -559,061 N
16,44298 16,44298 16,44298 16,44298 Nm
278,8187 204,8253 204,8253 278,8187 Nm
-281,832 -281,832 -232,503 -232,503 Nm
ACKNOWLEDGEMENT
This work was supported by CNCSIS - UEFISCDI, project number PN-II-RU
683/2010.
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REFERENCES
[1] BUZDUGAN, GH., Strength of Materials , Technical Publishing House Bucharest, 1980;
[2]. CORERBAN , J.,Calculul des structures, Dunord, Paris, 1972;
[3]. DIMENTBERG, F.,Teoriza vintovi eepriloyheniya, Nauka, Moskva, 1978;
[4]. GRIGORE, J.-C., Dynamics of mechanisms with clearances, Publisher University of
Pitesti, 2010;
[5]. PANDREA, N., Relative displacement method to calculate elastic systems. Journal of
Higher Education, Pitesti, 1978;
[6]. PANDREA, N., Elements of solid mechanics coordinate plückeriene, Romanian
Academy Publishing House, Bucharest 2000;
[7]. PANDREA, M., Calculation in linear elastic coordinates plückeriene, Publisher
University of Pitesti,, 2006;
[8]. VOINEA, R., PANDREA, N., Contributions to a general mathematical theory of
kinematic couplings, IFTOMM Ins. Symp.,Vol B, Bucharest 1973;
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DЕTERMINATION OF THE DRUM MILLS’ ENGINE CAPACITY BY USING
NEURAL NETWORK WITH SUBORDINATE INPUT PARAMETERS
Ph.D eng. Teodora HRISTOVA, UMG ―St. Ivan Rilski‖, Sofia, BULGARIA,
[email protected]
Ph.D eng. Ivan MININ, UMG ―St. Ivan Rilski‖, Sofia, BULGARIA
ABSTRACT: A successful experiment has been done to train the neural network to determine the drum mills’
engine capacity by using the program „QwikNet 2.23‖. As a result we get a trained neural network with a
maximum error of 1.00619.10-5 which can be used for assessing the capacity of the electric motors of drum mills
and can be considered an accurate mathematical model.
KEY WORDS: neural network, drum mill‘s engine, subordinate input parameters
1.Introduction of the problem.
During the last years assessing the parameters of electric engines is unthinkable without
using computers and programs. When determining the drum mills‘ engine capacity are used
algorithms in which as input parameters count the sizes (measurements), the angular velocity
and the drum mills‘ load with grinding forms. In most cases it turns out that the calculated
capacity is usually lower than the requisite amount which leads to installing a much more
powerful motor of calculations.
To facilitate the designer‘s activities, the algorithms for calculating the engines‘ capacity
that operate the drum crushers become automated by using computer calculation programs.
The easiest way is to use EXCEL or MatLab . In spite of inputting of correction coefficients
the engine‘s calculated capacity differs again to the one installed in the factory-producer. This
is probably because of the fact that many of the input parameters, taking part in the techniques
that calculate the mill‘s engine capacity cannot be set correctly and differ from the real ones.
For example when determining the sphere‘s load of the drum mills it is assumed that all
spheres in the drum of the mill have the same diameter. But it came to be known that when
proceeding the spheres fatigue and decrease their diameter which leads to increasing the
density of the grinding medium, its weight and increasing the capacity spent for raising and
transmitting the kinetic energy of the spheres.
To solve this problem it is decided that a neural network should be trained by which
the determination of the drum mills‘ engine capacity is going to be done more precisely.
2.Essense of neural networks
The neural network is a mathematical program consisted of interrelated simple computing
elements (neurons). The two most essential characteristics of the neural networks are : the
ability to ―learn‖ and to ―generalize‖. When ―learning‖ every neuron accepts signals from the
others (in the forms of numbers), processes them by a relevant mathematical algorithm and
defines its activation which is being transmitted by the outgoing connections to the other
neurons. Every connection has weight which multiplicated with the signal defines the
significance (power). The connections‘ weight are analogical to power of the junctional
impulses transmitted between the biological neurons. The negative weight value corresponds
to a suppressive impulse and the positive – to a stimulating impulse. The neural network has
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an input and output layer and also several intermediate layers. To achieve accurateness on a
higher level the intermediate layers in the neuronal network could be several.
After training the neuronal network in a relevant mathematical algorithm a new array is
being entered consisting of data that wasn‘t used for the training and the system generates
new gates (Ivanova,2004).
The neural networks can be classified according to different principles. According to the
training algorithm they can be with a straightway and contrariwise diffusion, fixed
increasement or with a contrariwise diffusion of the mistake. The most used and successful
instrument for prognosis is the neural network with a straightway diffusion (Zhang,2004).
This type of neural network is being used in 80% of the researches devoted to connectional
approach (Remus,2001) and its application in solving predicative problems as its in this case
and also the task to determine the capacity of the engine.
With the development of the technologies there are operated neural networks to
prognosticate the traffic load, to define the sale or other statistic tasks.
For the training of a neural network to determine the capacity of an engine, operating the
sphere‘s mill, is chosen universal neural network QwikNet2.23 in which array can be used
several types of training algorithms.
A data array is being created from the sizes and the load of the working mills and in the
gate of the mill are set the parameters of the engine working in real conditions.
The weights of the created neural network are being calculated and as the principle of
inputting data is this one : in the neural network the input and output parameters are set. The
output parameters are being assigned by an expert assessment or taken from real data. After
that the network is being trained until a certain percent of mistake is reached.
The weights that are gotten show the rank of influence between the entrances and the
exits.
3. Results from the neuronal network teaching
A neuronal network with three layers is being trained – one input, one internal and one
output. The entrances are 7. The ones with interrelated input parameters are : the thickness of
the facing, mm and the mass of the sphere or the bar load. Independent from each other
entrances are 5 : the internal diameter of the drum, mm; volume of the drum, m3; and speed of
the mill, min -1; internal diameter of the drum, mm with relative angular velocity of the drum,
% . In the hidden layer there are 5 meetings and one outset – capacity of the engine. Between
the entrances exists a connection. Several training algorithms are researched - Rprop,
Quickprop, Backprop и Delta-bar-delta.
The least mistake when teaching a neural network is when the Rprop algorithm is used
(Hristova and Minin,2012). The correlation mistake is 1.00619.10-5 and the maximum is
3.76222.10-5 which is very low value for an engineering problem. On account of it there is no
need to train the neuronal network more intermediate layers.
Correspondingly are the weights shown in table 1.
Table 1.
Neurons’ weights
1
2
3
4
5
6
7
8
0.21
0.088
0.101
0.009
0.548
0.53
0.018
3256
5575
925
3619
423
5239
9155
0.10442
0.10
0.196
0.059
0.324
0.135
0.48
0.134
0.243
7766
373
9555
386
178
1715
074
383
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0.32
2921
0.53
0203
0.560
508
0.003
1545
0.10
2346
0.117
929
0.469
0.553
312
0.199
321
0.495
522
0.174
821
0.091
8718
0.24
682
0.33
1125
0.245332
0.143651
0.004133
0.165
702
0.011
7241
0.40
7647
0.018
403
41
0.247
247
0.076257
7
0.256016
In table 2 there are visualized the parameters of a ―taught‖ neuronal network .
Table 2.
Parameter
Epochs
Value
100000
Parameter
Initial_Weight_Step_
Size
Teaching algorithm
Rprop
Momentum
Weight_Increase_Rate
1.2
Input_Noise
Weight_Decrease_Rate
0.5
Weight_Decay
Min_Weight_Step_Size
1e-006
Final_RMS_error
Max_Weight_Step_Size
50
Max error
*
In table 2 Epochs is the number of teaching repetitions.
The results of a teaching mistake are visualized in the next graphics.
(Figure 1)
Value
0.001
0
0
0
1.00619.10-5
- 3.76222.10-5
Figure 1
On figure 2 is it shown a taught neuronal network. The colour of the connections defines
the mistake and also shows that in the exit it is in the interval 0 -1.
Figure 2.
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The colouring of the neural network connections shows that the calculation is accurate
which means that their weights are being calculated right. To achieve a better training there
are an average number of calculating repetitions because it is acknowledged that some
teaching algorithms when increasing the number of repetitions the mistake grows too
(Kissiova and Radulov, 2002). The results of the testing report a very low mistake.
When testing the system more accurate prognostic data to determine the capacity of the
engine compared to the trained neural network with independent input data (Hristova and
Minin,2012). . The correlation mistake is - Final_RMS_error - 1.00619.10-5 and the
maximum mistake is Final_Max_error - 3.76222.10-5.
On the next graphics (Figure 3) there is the data of the testing algorithm when there isn‘t
one entrance. Unlike the researches done with independent input data because of the link
between the input data, prognosticating of the engine‘s capacity is done with a lower mistake.
It is concluded that when teaching the neuronal network it is necessary to have more input
data some of which to have a connection in between. This way, in case it is needed to
determine the capacity of the motor and when there is an input parameter missing if the
parameter is dependent on the other parameters, the value we get in end is going to be correct.
This quality of the neural networks can be used in determing the capacity in rooted already
working mills, if it is necessary to repair or change the work load caused of the change in the
technology.
Figure 3
On the next figure (figure4) it is clearly seen that the output data for determing the
capacity of the engine have a lower mistake compared to the ones determined with no
connection between the entrances on the graphs (Hristova and Minin,2012).
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Figure 4.
3.Conclusions
The trained neural network can be used for determining the capacity of the engines of all
kinds of drum mills and can be considered a reliable mathematical model. Defining the
capacity of the engine that operates a big industrious equipment is a responsible engineering
assignment and it is recommended to use standard algorithm in parallel with neural network.
Still the neural network is a reliable indicator for the engine‘s capacity as the accurateness of
the prognosis is higher when using dependent input parameters. It can be used when
designing dressing factories related to a determining of the motions installed in the mills‘
department.
References:
1.
Ivanova Mausya http://www.bam.bg/ravda2004/Ivanova_Marusya.htm
2.
Hristova Teodora, Minin Ivan "Determination of engine power of drum mills
using neural network with independent input parameters", Sofia, Annual of UMG,
Volume 55,2012, part "Mechanization, electrification and automation of mining" , in
press
3.
Kissiova Teodora, G. Radulov, E. Gegov, V. Christov ― Logical-probabilistic
model for assessing the relationship between environmental pollution according to
productivity and climatic conditions in ―GORUBSO ROF‖, Interenational Symposium
―Ecology‖, 2002, pp.393-401
4.
Remus, W., O`Connor, M ., ―Neural network time-series forecasting‖ in in
Armstrong, J . (Ed.) ―Principles of forecasting: a handbook for researchers and
practitioners‖, Kluwer Academic Publishers , 2001 , pp.246.
5.
Zhang, P ., ―Neural networks in business forecasting‖, Idea Group Inc. ,
2004, pp.3.
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ENTERPRISE SERVICES ARCHITECTURE IN THE WORLD OF
INFORMATION TECHNOLOGY
Ph.D., Stefan IOVAN, Informatica Feroviara SA, Bucuresti, [email protected]
Ph.D. Candidate, Gheorghe Iulian DAIAN, Informatica Feroviara SA, Cluj-Napoca,
[email protected]
Abstract: Enterprise Services Architecture (ESA) is blueprint for now enterprise software should be constructed
to provide maximum business value. The challenge facing most companies is not whether to adopt ServiceOriented Architecture (SOA), but when and how to do so. There is always a lag between technological vision
and business feasibility. It also takes time to fully realize the potential of existing technologies, a process that
does not stop the moment the new thing arrives. But when the value of a new approach such as ESA starts to
make a difference and produces a competitive advantage, the motivation to change skyrockets. The time to
change becomes now and the hunger for learning grows. The goal of this paper is to satisfy the hunger for
information for those who suspect that ESA may be a gateway to transforming Information Technology (IT) into
a strategic weapon. This paper will explain – in more detail that ever before – what ESA is bringing the concept
to life in all of its products as a platform supported by an ecosystem.
Keywords: Enterprise Services Architecture, Service Oriented Architecture, users interface,
1. INTRODUCTION
The current state of the art is a long way from ESA. Most enterprise software programs
now use Internet-inspired technologies, such as portals, web-based User Interfaces (UIs),
application servers, and XML-based messaging services, but they still cling to client/server
and even mainframe this will change dramatically over next six years. IT will become
connected by networks, awash in data, faster, more adaptive, and more in sync with business.
Companies that understand how to unlock the business value of this new architecture before
their competitors do will have a huge advantage.
The skeptics among us cannot help but ask, ―Has something really changed?‖
Buzzwords – web services, service-oriented architecture, and enterprise service bus are the
current rage – come and go, but the network, the Internet, is here to stay. ESA represents a
refactoring of the core architecture of enterprise applications to make sense of a flock of new
possibilities and to bring them in formation to the level of business, application, and
technology architectures.
IT will change not simply because new things are possible, but because most markets
are presenting companies with a whole new set of requirements that traditional IT is having a
hard time meeting. Most companies live in a world in which business models change every
year, on even more frequently. An implementation cycle of a year or more an IT project can
no longer be tolerated. New processes must be designed and built in three months, six months,
or nine months. The systems of record that provide the context for most business activity have
been built out. Now the challenge is to quickly a new layer of flexible processes based on
those systems of record in a way that preserves flexibility so that future adjustments are
affordable.
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2. WHAT FORCES CREATED ESA?
Modern businesses need functionality that is both distributed and centralized. Existing
systems of record, such as Enterprise Resources Planning (ERP), Customer Relationship
Management (CRM), Supply Chain Management (SCM), and so on, serve the needs of key
segments of the organization. But at the same time, a need for many new processes has arisen
that requires a flow that moves from one system of record to another, with the context for the
process kept outside of any of the existing systems. The traditional way of building enterprise
software is not well-suited to these new requirements and does not take full advantage of the
new world of pervasive networks, reusable services, and distributed data. Treating an
application as a self –contained world no longer meets the needs of business.
In the past, enterprise applications contained the end-to-end processes that were being
automated. One program running on one computer automated a workflow process that began
and ended inside application. A single database was the central mechanism of integration. All
elements of the stack were contained within one program, as shown in Figure 1.
Figure 1 actually shows a prettier picture than what exists in many mainframe
applications. Even after workflow mechanisms were in use and points of integration [1] were
designed, process and integration logic ended up strewn all over the stack and was mixed in
with application and UI logic. This structure, however, captures the spirit of mainframe
applications, which at their best were organized into the following layers:
 The UI layer
 The process logic layer (which controls the automation of the steps)
 The integration logic layer (which controls the way the program interact)
 The application logic layer (which controls what the program is actually doing)
 The persistence layer that serves as the database (where all the information is
stored).
Mainframe and client/server applications had complete control
of the stack from top to bottom.
Mainframe and Client/Server Applications
User interface
Process logic
Integration logic
Application logic
Persistence
Developers were able to control a vertical slice when coding from UI
to persistence. A single, consistent database was the point of integration.
Figure 1. Mainframe and client/sever architecture
From a development perspective, the mainframe and client/server tools gave developers
control over a vertical slice of this stack, from UI to the persistence layer. If functionality in
other slices was to be reused, the developer would have a conversation with the developers of
the other slices to figure out how to use their functionality. Everything came together and had
to be carefully reconciled in the database, which was the central point of integration. One of
the major points of ESA is to transform such conversations about reuse from an ad hoc event
into a formal design based on the needs of business processes.
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It is possible to access the functionality in a mainframe/client/server stack through
application programming interfaces (APIs) [4]. But there was no template for this; each time
an API was developed, it came with its own assumptions about how it worked and how it
should be used.
The mainframe/client/server applications did anticipate the need for customization
through metadata, different variables controlling an application‘s behavior, and templates for
UIs. But because the stack contained within one application, with the UI, process, application,
integration, and information layers tightly coupled at design time, it was impossible to break
open a mainframe application and restructure it to solve new problems.
3. APPLICATION PROLIFERATION
In the late 1980s and 1990s, ERP systems showed the power of the mainframe/ client/
server stack. Despite growing pains, the widespread success of ERP – with SAP leading the
charge – led to the creation of other applications, as seen in Figure 2.
ERP
SCM
User interface
Process logic
Integration
logic
Application
logic
Persistence
User interface
Process logic
Integration
logic
Application
logic
Persistence
CRM
SRM
User interface
Process logic
Integration
logic
Application
logic
Persistence
User interface
Process logic
Integration
logic
Application
logic
Persistence
Figure 2. Many applications, many vendors
While ERP was focused primarily on only the financial and management aspects of a
company – before it expanded throughout the 1990s to sales, distribution, on other key
functions – new applications such as CRM, SCM, and supplier relationship management
(SRM), among other expanded the range of automation. This led to a proliferation of
applications for most companies under the label ―best of breed‖. The idea was to get the best
application for each purpose. This allowed the VP of manufacturing the best SCM
application, and so on. The main benefit of this proliferation was the creation of a
comprehensive collection of systems of record that automated common business processes
from end to end.
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But solutions from different vendors created a problem because they took away the
central point of integration in the mainframe/ client/ server world: the single database. Data
was scattered all over the system landscape, or even worse, was duplicated in multiple
systems.
Communication and integration [2, 3] among applications became even more important
when companies realized that essential processes may flow through several enterprise
applications. The process that starts with taking and order and ends with the receipt of money,
the so-called ―order to cash‖ process, involved many enterprise applications. A financial
transaction in the ERP system would move to the SCM system for a factory order, which then
went to the CRM system for service questions, and then back to ERP for the final
confirmation of the order. Getting it to work at all actually required expensive, hard-wired
integration projects.
4. BRIDGING THE GAP AMONG SYSTEMS OF RECORD
The next challenge facing companies using enterprise applications was integration [5]
by SOA. Hence enterprise SOA [7] is a new standard which allows integrating the
functionality of existing SAP applications. How could all of the best-of-breed applications be
made to work together to serve the needs of the cross-application process that were becoming
the key to increased efficiency and innovation? As shown in Figure 3, the key question
concerned how to bridge the gap among systems of record.
ERP
User interface
Process logic
Integration
logic
Application
logic
Persistence
Portals
Business
process
management
Enterprise
application
integration
CRM
User interface
Process logic
Integration
logic
Application
logic
Persistence
SCM
User interface
Process logic
Integration
logic
Application
logic
Persistence
SRM
Data
warehouse
Application
server
User interface
Process logic
Integration
logic
Application
logic
Persistence
Figure 3. New solution emerged to connect and unify the distributed enterprise applications.
Many different technologies emerged to bridge the gap, so a cross-application,
integrated view of enterprise applications was created, based on the new possibilities of the
Internet as a pervasive network and emerging technology standards such as HTTP, HTML,
Java and XML:
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 Portals emerged as web-based UI technology that enabled one UI to connect to
functionality from the different applications [6].
 Data warehouse collected data from all of the different databases within the
applications in one place.
 Enterprise Application Integration (EAI) technology created engines that allowed
one application to send XML message – a standard for data formatting – to another
application, B2B [2, 3]. The receiving application could send a response back, and
all sorts of fancy alerting, monitoring, and triggering could happen in central systems
for routing and transforming messages.
 Business Process Management applications for process modeling and management
were frequently coupled with EAI technologies to create a new way to define and
execute processes in the center.
 Many of these integration tools were powered by application server, a new sort of
structure for applications based on standards such as Java 2 Enterprise Edition
(J2EE) that were created for the world of the Internet.
These new technologies started to bridge the gap among isolated enterprise applications
and enabled some cross-application coordination and development. The results were
encouraging. Portals could bring together UI elements from different applications, as well as
gathering information from different sources and displaying them in one place. Data
warehouse created one view of distributed information, albeit with a delay caused by batchoriented extraction processes. EAI technologies connected applications, but these connections
were complex and threatened a new layer of unstandardized spaghetti. Parts of the gap were
bridged with these approaches and the requirements from cross-application processes were
met to some extent. These capabilities fell far short of a unified approach to UI, process, and
information integration, however. They also ushered in a new set of problems – integration of
the integration technologies.
Portals might need to talk the data warehouse, which may need to send and receive data
through the EAI system, which could be working with a Business Process Management
system. The same sort of integration problems hat these technologies were designed to resolve
among enterprise applications arose among the integration technologies, which also generally
came from a variety of vendors. It was ―best of breed‖ all over again, except this time; it
concerned integration tools, not applications.
6. EXAMPLE: mySAP Business Suite and SAP NetWeaver
The cost of integrating enterprise applications and integrating integration technologies
quickly mounted, leading customers to ask, ―Is this really our problem to solve?‖ SAP
thought not, and solved this problem in two ways. First, SAP assembled its own solutions for
ERP, CRM, SCM, SRM, and so forth into a unified collection called the myAP Business
Suite. Second, SAP integrated all of the integration technologies into a unified whole, called
SAP NetWeaver. Furthermore, SAP started to develop all of its mySAP Business Suite
applications using SAP NetWeaver: in other words, integrated applications built on integrated
technologies as a platform.
This created the situation shown in Figure 4 in which an integrated set of tools could
help manage processes across a set of enterprise applications designed to work together.
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This approach solved a large portion in the problem of connecting enterprise
applications and integration technologies to each other.
SAP NetWeaver allows you to write programs not only in ABAP – the language that
has been used for more than 20 years to write applications in SAP – but also in Java [7]. This
helps solve the problem of integrating the integration tools, but still the problem of getting all
of these applications to talk to each other remains.
Bringing all of the applications together in the mySAP Business Suite helped solve the
second half of the cross-application integration problem in a variety of ways. SAP was able to
add business packages to configure enterprise applications to work together.
mySAP
ERPinterface
User
SAP NetWeaver
Process logic
Integration
logic
Application
logic
Persistence
Portals, Collaboration,
Multi-Channel Access
Business Intelligence,
Knowledge Management,
Master Data Management
mySAP CRM
User interface
Process logic
Integration
logic
Application
logic
Persistence
Integration Broker,
Business Process
Management
Application server
J2EE and ABAP
DB and OS Abstraction
mySAP
SCMinterface
User
Process logic
Integration
logic
Application
logic
Persistence
mySAP
SRM
User interface
Process logic
Integration
logic
Application
logic
Persistence
Figure 4. SAP unified enterprise applications into mySAP Business Suite and combined integration
components into SAP NetWeaver, which became a technology platform for the development of
enterprise applications.
The challenge still remained, however, to be able to recombine systems of record to
solve new problems. The connections made possible by SAP NetWeaver allowed some
processes to flow from one enterprise application to another, and solve a host of other
problems as well. Much of the power of enterprise applications was still locked in the
monolithic structure. Business needed to change faster than the connections between
applications could be constructed.
7. REFERENCES
[1] A. Y. Halevy and et al. ―Enterprise information integration: successes, challenges and
controversies‖, In SIGMOD Conference, pg. 778-787, 2005.
[2] B. Medjahed, B. Benatallah, A. Bouguettaya, A. H. H. Ngu, A. K. Elmagarmid,
―Business-to-business interactions: issues and enabling technologies‖. The VLDB J., 12(1),
pg. 59-85, 2003.
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[3] D. J. Kim, M. Agrawal, B. Jayaraman, H. R. Rao, ―A comparison of B2B e-service
solutions‖, Commun. ACM, 46(12), pg. 317-324, 2003.
[4] Hristina Daskalova, Tatiana Atanassova, ―Integration Platforms – Problems and
Possibilities‖, Cybernetics And Information Technologies, Volume 8, No 2, Institute of
Information Technologies, 1113 Sofia, 2008.
[5] Haas, Laura. ―Beauty and the Beast: The Theory and Practice of Information Integration‖,
11th International Conference on Database Theory (ICDT 2007), Barcelona, Spain, 2007.
[6] Daniel, F., Matera, M., Yu, J. Benatalla, B. Saint-Paul, R., Casati, F., ―Understanding UI
Integration. A Survey of Problems, Technologies, and Opportunities‖, IEEE Internet
Computing, 11, 3, pg. 59-66, 2007.
[7] Robert Heidasch, ‖Get ready for the next generation of SAP business applications based
on the Enterprise Service-Oriented Architecture (Enterprise SOA)‖, SAP Profesional Journal.
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INTERMODAL TRANSPORT AND STANDARDISATION
Ph.D. Candidate, Marcel LITRA, C.N.C.F. ―CFR-SA‖, Bucuresti, [email protected]
Ph.D., Stefan IOVAN, Informatica Feroviara SA, Bucuresti, [email protected]
Abstract: Almost gone unnoticed, a new era started in rail freight transport. Whereas the conventional
―wagonload‖ rail freight transport stagnates, road-rail Combined Transport (CT) was able to register high
growth rates. Direct trains link big cities at competitive costs and speeds compared to road. The share of CT in
the performance of freight transport (t/km) of European railway undertakings represents 25-40%. More than
1200 freight trains per working day, each with an average transport capacity of 25 truck loads, travel 500 km on
national and 950 km on cross-border relations, which in comparison with road freight transport results in a
75% reduction of CO2 emissions.
Keywords: intermodal, combined transport, freight containers, BIC-code, ILU-code
1. INTRODUCTION
The introduction of containers and their worldwide standardization based on
International Organization for Standardization (ISO) standards has resulted in increased
efficiency of deep sea shipping which in turn brought about a significant expansion of world
trade and created the basis for globalization. In continental transport, intermodality enables to
combine the advantages of two or more transport modes, for instance the high transport
capacity, security and environmental performance of rail or inland navigation with the
flexibility of road over short distances and in dense urban settings.
Intermodal transport is economically attractive and efficient in two different cases:
 Transport chains to and from overseas destinations involve a section on water and
several sections overland. Intermodal transport technology, with its easy transfers
from one transport system to another, is particularly efficient in this case.
Transshipment of an intermodal transport unit, a 40-foot container for example,
enables a load of almost 80 m3 to be transferred from a ship to an HGV or rail
wagon in a single operation lasting 3 minutes. Conventional transshipment as it was
carried out in the past, with each package being lifted from the ship and loaded onto
another vehicle, would take several hours.
 Over long distances, especially in land transport, the numerous individual
consignments can be gathered together into a large consignment at the beginning of
the journey, divided once again in the destination area and distributed to the
consignees. For example, loading units are carried by road to a transshipment facility
where they are transshipped onto a block train and transported to a destination
terminal. They are then transshipped onto road vehicles and sent onwards. A block
train can transport some 80 seven-meter swap bodies on most European railways,
which means it can carry the same load as 40 trailer trains to a destination area in a
more cost-effective and energy-saving fashion.
These two different forms of intermodal traffic also have their different business
models:
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 The major players retain their traditional role when intermodal traffic is used to
organize transport chains to overseas destinations rationally and efficiently. Shipping
companies organize sea transport, port transshipment companies take care of
container transshipment in the sea port, and haulers and land transport companies
carry the container from the port to its hinterland destination. However, in the course
of containerization, the companies involved have organized themselves into
worldwide businesses, especially in terms of sea transport and transshipment in ports
[1]. The intermodal traffic system has been successful mainly through cost
regression and increased operational scale. Correspondingly, the size of the
companies involved has increased dramatically. Medium-sized service providers
only exists alongside major railways and their subsidiaries in container transport
from sea ports to the hinterland [1].
 The second intermodal traffic model, which involves grouping many individual
loads together into large transport units, created a new type of business, the
combined transport operator, which in a sense works as a consolidator company. In
the past, many railways in the USA and Europe also carried out intermodal traffic
through their own subsidiaries. At the same time, freight forwarders and road freight
companies founded their own businesses together to organize combined transport.
These companies would purchase the capacity of an entire block train from a rail
company and sell it on to haulers and goods transport companies space by space.
They usually also assumed the risk in terms of train capacity utilization in these
intermodal operations. As the railway leading operations made a significant
contribution to the success (or failure) of an intermodal transport service through the
quality (or distinct lack of quality) of its performance, operators try to ensure, as
much as their market power allows them, that their contracts with railway companies
make sure the latter would strive towards transport quality.
The new EN 13044 standard for the marking of intermodal loading units simplifies the
access to Combined Transport and brings efficiency improvements for all for all those
involved. The initiative embodied in EN 13044 and the Intermodal Loading Units (ILU) –
Code is a prime example for industry voluntarily regulating itself: a solution which the
European Commission much prefers, especially when it embraces important security-related
considerations, while also enhancing operational efficiency, all without the intervention of the
legislator.
ISO containers are shipped on road, by inland waterway or rail mainly in seaport
hinterland traffic; in continental transport easy-to-transship loading units, standardized
European Committee for Standardization (ECS) swap-bodies and semi-trailers are used.
These are better adapted to the dimensions of road vehicles and are also lighter and easier to
load. Due to common technical characteristics, many road vehicles, wagons and
transshipment devices are suitable for use with every type of loading unit. Also the owner
identification of European loading units and ISO-Containers will develop in a compatible way
in the coming years.
2. AUTHORISATION AND CODIFICATION
The forwarding of loading units on rail wagons almost always exceeds the normal
loading gauge of average railway lines and can therefore only run on sections of the rail
network which have been specifically measured and certified for an increased loading gauge.
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A gauge code is allocated to these railway lines, which indicates the maximum dimension of
loading units that may use the route referring to standard CT wagon.
The CT loading units (swap-bodies, non-ISO containers and semi-trailers) also need to
have a corresponding codification. To be able to run on a given rail route, the gauge code of
the loading unit cannot exceeds the codes of the railway lines making up the route. Moreover,
some wagons with very low loading platforms may have correction digits – differentiated
from country to country – which permit the passage of loading units that are higher by a few
centimeters. Over the years, rail gauges (especially limited in rail tunnels) have continually
improved on several important railway lines in order to allow the passage on rail by almost
any loading unit transported on road.
Intermodal loading units require certification to be transported by rail and must be fitted
with a gauge code. In accordance with EN 13044, this ―codification‖ for swap-bodies and
semi-trailers will be carried out directly by the manufacturer. He will submit the design plans
and related calculations to the competent authorities (railway undertaking, CT operators or
certification instances) followed by, if necessary, a resistance test to ensure that the design the
ECS standards or UIC leaflets. The loading units then will receive a codification plate which
certifies rail compliance and contains all the essential information to operations: for swapbodies the gauge, length, width code and the resistance category, while for semi-trailers:
important information for the quick and safe loading (carriage height, compatibility code for
pocket wagons).
The manufacturer has to guarantee towards the buyer and third party that the delivered
units comply with the certified design.
Figure 1 New codification plates compliant with the EN 13044 standard for swap-bodies and semitrailers (for each and according to preference: horizontal or vertical)
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3. IDENTIFICATION AND STANDARDISED OWNER CODES
The current standard for a maritime container is the worldwide ISO 6346 standard
which describes the BIC-Code allocated by the ―Bureau International de Containers‖. Nearly
2000 BIC owner code have been issued up to now, thus enabling the owners of ISOcontainers (ship owners, carriers or leasing companies) to effectively identify the ownership
of more than 20 million freight containers worldwide.
The capacity of the BIC-Code, with a ―U‖ for ―freight containers‖ in the 4th place,
permits the allocation of nearly 17000 codes. This would not be sufficient if all European
entities owning loading units wanted to obtain such a code. For the loading units being mainly
used within Europe (swap-bodies and semi-trailers), a technically compatible ―ILU-Code‖ is
introduced by the European EN 13044 standard, which will be administered by the
International Union of Combined Road-Rail Transport Companies (UIRR).
Example. In the USA, the ―National Motor Freight Traffic Association‖ (NMFTA)
allocates the ―Standard Carrier Alpha Code‖ (SCAC) to identify freight carriers and their
loading units. Since the loading units marked with the SCAC, mostly semi-trailers, remain on
the American continent, the European loading units can receive a similarly structured ILUCode as they will be deployed exclusively within Europe. NMFTA has ensured that it would
not allocate owner codes with ―U‖, ―J‖ or ―Z‖, as these is reserved for the worldwide BICCode.
In the future, only one uniform type of owner identification will be applied on loading
units: the worldwide BIC-Code for freight containers and the new compatible ILU-Code for
European loading units where BIC and UIRR are the issues of the owner-key. The marking on
every loading unit looks as follows:
Owner-key – Registration number – Check digit
ABCD 001234 3
Owner-key
Allocation by UIRR or BIC
4th alpha character for type of loading unit (ISO 6346
requires ―U‖ on the last place for containers, ―J‖ for
equipment fitted on the container and ―Z‖ for trailers and the
chassis. The EN 13044 requires a ―A‖, ―B‖, ―C‖, ―D‖, ―E‖ or
―K‖ for ILUs with restricted use for Europe.)
Registration number:
Check digit:
Free allocation by owner
Given calculation procedure
3.1. BIC-Code or ILU-Code?
For companies owning European loading units, the administrative costs of codification
and of the yellow plate for each individual unit will disappear in the future. Instead, they will
need a BIC-Code or an ILU-Code as owner–key for the identification of all of their loading
units. Every actor from the maritime sector and owner of ISO containers already having a
BIC-Code may, according to the ISO 6346 standard, mark all freight containers, including
swap-bodies [2].
The ILU-Code, which is compatible with the BIC-Code has been conceived for those
companies who one swap-bodies and semi-trailers used in European intermodal transport on
road, inland navigation and short distance sea shipping [3]. Companies already in possession
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of a BIC-Code will only need to acquire an ILU-Code if they also own semi-trailers. On
request, they can get an ILU-Code ending with ―K‖ and with the first three letters matching
their BIC-Code.
3.2. Launching and transition rules
The expected efficiency improvements will become visible when after a transition
period only the new markings are used. UIC railway undertakings and UIRR operators have
therefore decided the following deployment plan:
1. From July 2011, UIRR will start issuing the ILU-Codes, while operational marking
will be carried out using the new codification plates.
2. After a three-year transition period, from July 2014, only loading units marked with
a BIC-Code or an ILU-Code will be accepted.
3. After an eight-year transition period, from July 2019, every loading unit will have to
be fitted with the new codification plate.
Administration of the owner code of companies based in several countries is not easy as
some of them move others close, etc. and the code database must always be updated. UIRR,
the administrator of the ILU-Code, is mainly financed by its member companies, which
enables it to charge fees at marginal cost and hence make this step easy to accept by the
transport sector [4]. The initial allocation of the ILU-Code will cost EUR 250, while the
renewal, due only every second year, EUR 100.
4. ADVANTAGES
The ILU-Code allows a simplification of the electronic data processing and operational
running for the actors of the transport chain. The code adapted to electronic data processing
reduces the number of data capture errors as 95% of the possible typing errors are
immediately spotted thanks to the check digit. The correction costs for the data capture errors
and the transmissions are thus considerably reduced.
The EN 13044 standard distinguishes the owner identification from the operational
marking requested for the rail operation. In future, ―codification‖ will be directly carried out
by the manufacturer. The yellow codification plate concerns characteristics of the intermodal
loading unit such as the geometric dimensions and the resistance which are retained in case of
a change of owner. In case of sale, a new codification is therefore not needed anymore.
All swap-bodies and crane able semi-trailers, even if purchased to be used in pure road
transport only, will be usable in rail transport. Logistics companies and road haulers will only
have to – as this is already the case for the containers – provide their loading units with their
owner-key consisting of four letters followed by six digits, with which they can codify their
rolling stock according to own criteria, to be followed by a check digit.
Every actor of the transport chain, as well as third parties, for example customs
authorities, emergency services, can at any time identify the owner of a loading unit given that
the owner code is published. This is important aspect for the checks at the borders but also
within EU for the future reinforced requirements in the field of security and safety. For more
efficient operations in ports and terminals, the custom authorities more and more check the
identity of containers directly with BIC. This procedure will in the future likely be extended
to all CT terminals [5]. Swap-bodies and semi-trailers fitted with an ILU-Code could then
also be checked and be shipped with priority.
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The BIC-/ILU-Code, written in larger characters, are OCR-readable. The systems which
are already installed at sea-ports can thus also find an application in the continental terminals
and contribute to their streamlining.
5. CONCLUSION
The introduction of the ILU-Code with check-digit will enable the saving of labor
thanks to the reduction data capture errors at the terminals. The time saved can rather be
devoted to improved customer service. The harmonized ISO 6346 an EN 13044 standards
have the potential to be used for identifying intermodal loading units in the information
exchange foreseen under the European regulation for freight telematics (TAF TSI) if extended
to intermodal traffic [5]. With BIC and UIRR, two renowned international organizations
manage the owner codes in the interest of the transport sector.
6. REFERENCES
[1] IONITA Profir, PLATON Stelian, IOVAN Stefan, The Terminal, Key Element of
Intermodal Transport / Terminalul element esential in transportul intermodal, Annals of the
―Constantin Brancusi‖ University of Targu Jiu, Engineering Series, No. 4/2011
(CONFERENG 2011), ISSN: 1842 – 4856, pg. 281 – 291, (2011);
[2] http://www.bic-code.org
[3] http://www.ilu-code.eu
[4] * * *, New marking of intermodal loading units in Europe, UIRR, (2011);
[5] SEIDELMANN Charles, 40 Years Combined Transport Road-Rail in Europe, UIRR,
(2010);
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AN THE ECUATION Re [(x-a)f(x)]=0, fєS
Professor.dr Miodrag IOVANOV
―Constantin Brâncuşi‖University of Târgu-Jiu
[email protected]
Abstract: Let S be the class of functions f(z)=z+a2z2…, f(0)=0, f′(0)=1 which are regular and univalent in the
unit disk |z|<1.
For 0≤x≤a≤1 we consider the equation
Re [(x-a)f(x)]=0, fєS.
and
Re [(x3-a3)f(x)]=0.
(1)
Denote φ(x)=Re [(x-a)f(x)]. Because φ(0)=0 and φ(a)=0 it follows that there is x0є(0,a) such that:
φ′( x0)=0.
The aim of this paper is to find max{x| φ′( x)=0}.
If x is max{x| φ′(x)=0}, then for x> x the equation φ′( x)=0 does not have real roots. Since S is a
compact class, there exists x .
This problem was first proposed by Petru T. Mocanu in [2]. We will determine x by using the
variational method of Schiffer-Goluzin [1].
Keywords: function, variation, finite number
The main results
Let f є S be the extremal function for which x is attained, which:
Re[f( x )+( x -a)f′( x )]=0.
Next we consider a variation of the function f given by Schiffer-Goluzin’s formula [1]:
f*(x)=f(x)+ λV(x; ζ; ψ)+ 0(λ2), | ζ |<1, λ>0,
(2)
ψ real number, where:

f 2 (x)
f ( ) 2
iψ
iψ
V(x; ; )  e f (x)  f ()  e  f (x)  [ f () ] 


2
eiψ xf (x)   [ f () ]2  e-iψ x f (x) [ f () ]2

x
f ( )
1  x f ( )
(3)
Next we consider a variation x* of x:
x*
x =x+λh+0(λ ), h 
 0
*
2
which satisfies the conditions:
|x*|=x and Re[f*(x*)+(x*-a)f′*(x*)]=0.
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We denote:
f  f (x), w  f (),   f (x),m  f (x),

V  V(x; ; ),V  VX (x; ; ).
(5)
By using (4) and (5) we obtain that the extremal function w=f(  ) must satisfy the
following equation:
4
k
 tk
 w  f [f  (x  a)]  f[f  2(x  a)]w
k=0
(6)


 
2
(f  w)
(x  ) 2 (1  x) 2
 w 
2
2
where Re t0=Re t4=0, Re t1=Re t3 and t0, t1, t2, t4, depending of x,f,ℓ, and m.
. It may be shown that the extremal function w=f(  ) maps the unit disk onto the entire w –
plane slit along a finite number of analytic arcs. Let q=eiθ be the point which is mapped into
4
an end – point of a slit. The polinomial
t 
k
k
has the double root   q. It follows that the
k=0
equation (6) may be written:
 w 2 f 2 [f  (x  a)]  f[f  2(x  a)]w


 
(f  w) 2
 w 
 2
2
2 2
 x (1  q )  [i(v  r)  2(u  iv)q  i(v  r)q  ]

(x   ) 2 (1  x ) 2
(7)
where u, v and r are real numbers and verifies:
(1  2x cos   x 2 cos 2)[2x(vsin   u cos )  x 2 (v  r)sin 2] 

2
2x sin (1  x cos )[v  r  2x(u sin   vcos )  x (v  r)cos 2] 
 (1  x 2 ) 2 Ref ,

2x sin (1  x cos )[2x(vsin   u cos )  x 2 (v  r)sin 2] 

(1  2x cos   x 2 cos 2)[v  r  2x(u sin   vcos )  x 2 (v  r)cos 2] 

 Im[(x  a)(1  x 2 ) 2 ],
 3
2
 5x  4ax  3x  2a  2x(x  cos )  N1  Re xm ,

 (1  x 2 )(x  a)
1  2x cos   x 2 N 2

sin 
N
xm

 3  Im
2
 1  2x cos   x
N4

(8)
where:
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N1  2 x(v r)(usinθ vcosθ)  2[2(u 2  v 2 )  (v 2  r 2 )cos 2θ]x 2 
........  6(v r)(usinθ vcosθ) x 3  2(v r) 2 x 4 ;
N 2  (v r)2  4 x(v r)(usinθ vcosθ)  2[2(u 2  v 2 )  (v 2  r 2 )cos 2θ]x 2 
.........  4(v r)(usinθ vcosθ) x 3  (v r) 2 x 4 ;
N 3  2 x(v r)( vsinθ ucosθ)  2(v 2  r 2 ) x 2sin 2θ  2(v r) 
........  (vsinθ ucosθ) x 3  4(v r)(vsinθ  ucosθ) x 3 ;
N4  (v r) 2  4 x(v r)(usinθ vcosθ)  2[2(u 2  v 2 )  (v 2  r 2 )cos 2θ]x 2 
........  4(v r)(usinθ vcosθ) x 3  (v r) 2 x 4 .
By (7) we obtain:
w(1 )=
f[f  (x  a)]
f  2(x  a)
(9)
u  iv  u 2  r 2  2uv  i
where 1    q , |  1 |<1,  
(  1 is root of equation i(v-r)i(v  r)
2(u+iv)q  +i(v+r)q2  2=0).
By integrating equation (7) we obtain that the extremal function w=f(  ) is given
implicitly by the equation:
s

 s1  1  1 f 2[f  (x  a)]  f 2[f  (x  a)]  f[f  2(x  a)]w

qk
f

2(x

a)





  2
 k  2 f[f  (x  a)]  s1  1 
f [f  (x  a)]  f 2[f  (x  a)]  f[f  2(x  a)]w

s1
  2
2
 f (x  a)  f [f  (x  a)]  f[f  2(x  a)]w 
 
 2
2

  f (x  a)  f [f  (x  a)]  f[f  2(x  a)]w 

1
1
s2
s3
s2
s3
 





  k    k    k       k      1  y  k    k y     y      y 

 

  k      k      k     1  y 
k y  y  y

(10)
  q
x  q2 2   xq2
vr
2
where: k 
, y
, 
, 
,
k
x


qk


xqk
vr
 q

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s1 
(x  q)(x  q)
(x  q)(x  q)
(x  a)
, s2 
and
.
s


3
f  (x  a)
 k (1  x 2 )
 k (1  x 2 )
If we put   x in (7) we obtain s1=s2. By using (9) and (10) we obtain:
 k 
qk
2  s1  1 
f
(1

s
)





1
k  2
 s1  1   k   
s1
1
k
s1
s3
  k   z k 

 
 (11)

k


z
k



 

The value of ρ, q, k, σ, z, s1 and s2 which appear in (10) depend of u, v and r; (8) and
(9) determine u, v and r as functions of θ, and θ is obtained from (9) and w′(0)=a2.
Thus f and ℓ being known, x is obtained from the condition: x =max{x|Re[f+(x-a)ℓ]=0}.
References:
[1] G.M.Goluzin, ―Geometriceskaia teoria funcţii complecsnogo peremennogo‖,
Moscova-Leningrad, 1952.
[2] P.T.Mocanu, An extremal problem for univalent functions, ―Babes-Bolyai‖
University, Faculty of Mathematics, Cluj-Napoca, 2010.
Miodrag Iovanov, University ―Constantin Brâncuşi‖ Târgu-Jiu.
e-mail: [email protected]; [email protected]
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IMPROVING THE PERFORMANCES OF THE CONTINUOUS
TRANSPORT INSTALLATIONS WITH BAND
PART I – USUAL PROBLEMS OF OPTIMIZING THE ACTION SYSTEMS OF
THE BAND TRANSPORTERS
PhD. Lecturer, Nicoleta-Maria MIHUT, University C-tin Brancusi of Tg-Jiu,
[email protected]
Abstract: Most of the systems of electric action are non-linear systems, including the continuous transport
systems with band, that could be brought by linearization and negligence at the linear system. The latest news in
the field of static convertors, of the new transfer schemes of electric energy, make possible the analysis of the
action systems of the continuous transport installations with band as linearisable systems. For the linearisable
action systems described by state equations, there are two consecrated calculation methods of the optimal
trajectory of the system, the variational calculation and the Euler-Lagrange algorithm, as the latter one is
considered by the specialty literature as an optimum generator, and the first one as an extremum generator. But
the two methods need conditions reviewed enough in the Euler-Lagrange conditions.
Keywords: continuous transport, non-linear systems, Euler-Lagrange algorithm
1. Introduction.
The optimal systems theory belongs to the general theory of systems and represents
the most evolved and important part of this field. Systems in general and the automatic
systems in particular cannot be conceived without considering their efficiency degree, the
framing in the minimum consumptions of time, energy, and materials, how much all the
available resources are required and capitalized, the minimum production costs, etc. For this
reason, any problem of calculation, projection, analysis and functioning of the continuous
transport systems is subordinated to the optimality requirements.
2. Usual problems of optimizing the action systems of the band transporters
Any process or technological installation, including the continuous transport
installations with band may be treated as a multivariable oriented system with memory,
benefiting from mathematic representations spotlighting its causal structure by input variables
u , state variables x and output variables y (fig. 1 Multivariable Oriented System)
x 0 (t)
u
y
x
Figure 1. Multivariable Oriented System
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A first mathematic description of the dynamic system is expressed by the initial mathematic
model. Considering the system as a flat system with concentrated parameters, the mathematic
model may be brought to look like a system of differential equations of first order:
F(x, x , t )  0
(1)
By separating the variables according to a causality criterion in input variables, state
variables and output variables, the model may be expressed in the 2 state equations:
x  F( x , u, t )
y  G ( x, u, t )
(2)
In calculating, projecting and functioning any system, we should consider the
limitations of the components of the system and the signals transmitted between these
elements. These limitations are called restrictions and they are generally of the (3) form and
the finding of an optimal solution should satisfy the conditions of the imposed restrictions:
r  ( x, t )  
(3)
The proper (active) input variable is real and limited by the fact that it should be
admitted at the system input under the physical nature aspect, under the aspect of the values it
may have and forming the vectorial input space, u  U   p and under the aspect of the
functioning giving in time these values that form the set of admitted input functions (non-void
set),
u  (t )  , t  T,   { : T  U}
The input variables may be continuous and derivable in report to t in a neighbourhood
of interval t 0 , t1   T , and the space the these sizes U is considered as open; flat on portions
in the interval [t0, t1]. Any element u(t), oh set U providing the system evolution in the initial
conditions in the final conditions by respecting the properties of controllability, tangibility
and observability is called an admitted order.
The state variable may be submitted or not to restrictions according to the specific of
the optimization problem, as there are the following situations:
- the set χ, where the system is defined, has no restrictions and it may cover the entire space
n ;
- the set χ is limited and opened in  n ;
- the set χ where the admitted states are restrained, is limited and closed in  n
The output variable is real and it depends on the values of the input variable and on
the system structure, and the set Y may be submitted or not to restrictions. The total values of
the constructive parameters pc and functional ones pa, admitted by the system, forms the
admitted fields Pa and respectively Pc,
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p a  Pa  l , p c  Pc   k ,
that are compact fields, usually limited and closed ones. From the analysis of the previous
restrictions, we notice that, for the good functioning of the system, the values admitted both
for the variables attached to the action system (input, state, output) and for the functional and
constructive parameters certain value intervals are found.
The admitted field of the system is definited by the total admitted values,
DA  {U, , Y, T, Pa , Pc }
that will have the respective restrictions as frontier. The admitted field imposes for the system
evolution to occur only inside it, so the solution of the optimization problem should be found
inside the admitted document.
From the systemic viewpoint in optimizing the electric actions of the continuous
transport installations with band, we should consider two aspects:
- the stationary system of determining optimal values of some sizes (speeds,
accelerations) and of constantly keeping them on relatively long times, without considering a
detailed study of the transitory systems;
- the dynamic system, having as an objective the determination of the parameters of the
automatic regulator providing a transitory system as short as possible.
The most often, the functioning cycle of an electric action system supposes a
succession of a finite number of stationary systems, a succession imposing the solving of both
of the optimization problems.
The result of this combination mostly leads to the accomplishment of a costly adaptive
optimal system. For removing this disadvantage, we adopt optimal solutions of the stationary
and suboptimal systems for the dynamic system problem.
Typical problems referring to the optimization of the functioning systems of the
electric action systems by particularizing the optimization criterion are:
a) The problem of minimum time has as an objective the minimization of the lapse of time
necessary for passing the system from the initial state to the final state by means of an
admitted order.
b) The problem of the minimum energy consumption supposes the determination of that
admissible order for which the system evolves from the initial state x 0   0 to the final state
x1  1 , mostly fixed in case of the electric actions, in the imposed lapse of time [t0, t1] or not,
so that the energy consumption should be minimum.
c) The problem of minimizing the final dispersion, existing in the minimization of the
positive-defined square shape,
1
J  x T ( t1 ) M x ( t1 )
2
(4)
d) The problem of final control. The optimization types imposing the problem of final
control are Mayer or Bolza problems, having as a purpose the determination of the free initial
or final states. These problems are mostly doubled by conditions derived from the necessity of
a minimum energetic consumption.
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3. Conclusions on the optimization methods
Most of the systems of electric action are non-linear systems, including the continuous
transport systems with band, that could be brought by linearization and negligence at the
linear system.
The latest news in the field of static convertors, of the new transfer schemes of electric
energy, make possible the analysis of the action systems of the continuous transport
installations with band as linearisable systems.
For the linearisable action systems described by state equations, there are two
consecrated calculation methods of the optimal trajectory of the system, the variational
calculation and the Euler-Lagrange algorithm, as the latter one is considered by the specialty
literature as an optimum generator, and the first one as an extremum generator.
The difference of expression between the two methods consists of the fact that the
variational method considers the quality index dependent on the state vector and on its
derivate, and the optimal order is obtained from the state equation after calculating the
optimal trajectory and Euler-Lagrange algorithm replaces the derivate of the state vector with
the order variable. But the two methods need conditions reviewed enough in the EulerLagrange conditions.
The problems of minimum time are reducible to the Euler-Lagrange equations if the state
derivates do not depend explicitly on time. Introducing the restrictions in the performance
criterion for these problem types decreases the number of possible solutions.
Solving an optimization crosses several stages, among which we mention:
- in a first stage, it is determined the mathematic model that should mathematically describe
the system functionality accomplished by differential equations. In case of linear systems, the
description may be expressed by means of the differential equation of input-output, by means
of the state equations, by means of the operational equation of input-output as the changed
Laplace, or by means of the transfer function. At the same time, we should spotlight the initial
and final conditions, the potential restrictions and the admitted field;
- in the second state, the optimization criterion is adopted and formulated mathematically;
- the third state is consecrated to formulating the optimization problem. The optimization
problem consists of determining the optimal values of decision in case of the static
optimization and in determining the optimal function of the order variable and of the extreme
trajectory that should transfer the system from the initial state to the final state in case of the
dynamic optimization, by providing the extreme optimization criterion, by satisfying the
existing connections and restrictions. Here, we also include the potential changes or the
necessary reductions.
- the following state is represented by the effective determination of the optimal solution.
Starting from the necessary extreme condition, we accomplish the necessary calculations, and
in most of the cases the computer is necessary, and in the end we analyse the nature of the
global extreme (minimum or maximum) and we check the sufficiency condition.
-the last stage consists of implementing the optimal solution in practice. This is possible only
by means of certain professional calculation equipments and of structures of purchasing and
processing data.
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References
[1] Amza Gheorghe, Tehnologia materialelor. Prelucrari cu ultrasunete, Institutul Politehnic
Bucuresti, 1984, pp 47-61.
[2] Giurgiulescu Barbu, Bercea Nicolae, Modernizarea acţionărilor electrice la utilajele
tehnologice din carierele de ligni, Editura Newest, Tg-Jiu, 2001, pp 25 - 34 ISBN 973-8043424-4.
[3] Ichim I., Marinescu G., Metode de aproximare numerica, Editura Academiei RSR,
Bucuresti, 1986, pp 256-270.
[4] Kopchenova, N., Maron, I., Computational Mathematics - Worked Examples and
Problems with Elements of Theory, Mir Publisher, Moskow, 1984, pp 123 - 130, ISBN
77356389.
[5]. Larionescu D., Metode numerice, Editura Tehnica , Bucuresti, 1989, pp 140 - 157.
[6] Mihuţ Nicoleta Maria, Contribuţii la îmbunătăţirea parametrilor tehnologici de
transport ai materialelor pe benzi, PhD thesis, University of Petrosani, Mechanical and
Electrical Faculty., Petrosani, 2007.
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IMPROVING THE PERFORMANCES OF THE CONTINUOUS
TRANSPORT INSTALLATIONS WITH BAND
PART II –DETERMINING THE OPTIMAL DEBT IN CONDITIONS OF
CONTINUOUS TRANSPORT WITH BAND
PhD. Lecturer, Nicoleta-Maria MIHUT, University C-tin Brancusi of Tg-Jiu,
[email protected]
Abstract: In order to determine the optimum capacity of band conveyers we start from the general equation,
the vee profile of the material section on band is imposed, its equation is being determined, the bedding
coefficient is being found out and its relation is further obtained for a maximum section of the material.
Relations between the band constructive parameters and the material profile are being defined which are
graphically displayed. Then, the issue of obtaining the maximum capacity through speed adjustment
depending on the gradient is being analyzed. On the base of the equation for the material balance, we obtain
the equation of the conveyed material volume under stationary regime and under dynamic regime and the
length which ensures the maximum area of the material section on the band. The material discharge is then
calculated depending on the gradient and the time constant of the continuous transport process is being
determined, necessary for the selection of acquisition equipments and data processing.
Keywords: continuous transport, the equation of the conveyed material volume, optimum capacity of band
conveyers
1. Introduction.
Knowing the area of the section of the transported material flow A, the transport speed
v, the specific weight of the loosened material, or the material mass on a linear meter of band
qm, for a continuous transport installation with band, the debt is determined by the general
equation of the continuous transport,
(1)
Q  k1 A v 
2. Determining the Optimal Debt in Conditions of Continuous Transport with Band
The section of the material flow is determined by the charged width of ben In case of
the continuous transport installations with band, it is about obtaining a maximum debt, by
regulating the speed, depending on a corresponding embankment angle. The establishment of
the equations describing the functioning of the transport system is made based on the
equations of the material balance sheet. Regulating the debt seems to be a simple problem
because the output size of the process is a debt, and the input size is the same debt and such
the transfer function would be equal to the unity. Changing the supply debt has, as a
consequence, the changing of the transport debt, so the flow cannot be changed without an
acceleration or deceleration. All of these are determined by the fact that, between the measure
element and the execution element, there is a flowing material volume featured by certain
inertia. The dynamic features of the system are mainly determined by the inertia of the
measure system of the debt, of the regulator and of the speed of the supplying band.
If it is necessary an exact regulation of the debt (supplying different installations) then
the time of the transitory system should be reduced, so the time constants of the elements
entering the composition of the regulation curl should be reduced at the possible minimum de
value.
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The balance sheet equation of material, considering the supplying debt Q1 the
transported debt Q2, the material mass on the length unit of band q and the volume of the total
flow of material transported on the band is:
dV
,
(2)
Q1  Q 2  q
dt
wherw considering the constructive and functional parameters, we obtain the volume of
transported materiel flow,
2


b2
1
b
(3)
V  L 0  tg   tg  1  2 tg 
2
2
 2


The volume of material flow corresponding to the length variation l , where there is
the speed change is:
2
2


1
 b1 b 2
(4)
V  L 0 A 20   tg   tg 

tg l
2
2
 2


We will determine the volume of the material flow in order to correspondingly provide
the length variation l the maximum imposed area. It is considered that from the charging
section, it starts the maximum debt, it is important to determine the distance where the
deviation should be made. It is interesting only the transversal section by the material flow
respecting the condition of maximum angle.
At the fall of the material perpendicularly on the band plan, we obtain the natural
embankment angle, and at the fall of the material flow under a certain angle (so in
movement), we obtain the moving embankment angle, d  0,4  0,6 0 .
For technological reasons, the width of depositing the material b1 is determined by the
constructive parameters of the band and by the nature of the transported material. Considering
the constructive parameters and keeping the longitudinal size and the imposed embankment
angle, because the corresponding falling cone is symmetric to all the generators, l is
determined as,
l 
2b  b tg 
h
 1 1
tg 
2
tg 
(5)
Even if the maximum flowing point of the material debt is at a bigger distance than the
abscise falling limit to the beginning of the charging point l  x .
The supply may be equated to the falling cone (fig.2), and the cone section is
determined by the shape of the lateral margin of the band, the idea is of keeping the
longitudinal sizes, at an imposed embankment angle.
The balance sheet equation in the falling area, correspondingly to the volume of the charging
area Vi, for a transport speed v, becomes,
dV
Q1  Q 2  q i
(6)
dt
The section along the material flow that is formed on the band having a shape hard to
explain, the volume of the charging area will be calculated by equation, considering that half
of cone, where a constant quantity is extracted from, given the band shape
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1
1
Vi  Vcon  Vk  l3 tg  Vk
2
6
According to the relation (6) the volume occupied by the material,
(7)
3
1
1  b2 b  b
1
V  x 3 y   1  1 2 tg  y 
6
6  2
2
y 
b 2 b  b 
b b  b 2 2 1 b  b 3 3 1 
  b13
 y  3 1 1 2 tg  3 1 1 2 tg  2  1 2 tg  3 
6  8
8
8
8
y
y 
(8)
Figure 1. Falling cone of the material
The natural embankment angle depends on the coal nature and granulation and it varies
between 36-38° for mixed coals, 28- 32° for fragmented lignite and 25-260 for nonfragmented lignite. In these conditions, the variation graphic of the volume occupied by the
material depending on the parameters b1 and b2 look like in figure 2,
Figure 2. Volume of the material depending on the parameters b 1 and b2
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3. Conclusions
When projecting and choosing the components of acting the transporter bands, it is imposed,
between the action engine, the transmitting mechanism and the transporting band, to exist such a
correlation that should provide the maximum energy (power) transfer, namely an optimum report of
transmitting the transmission mechanism
The algorithm of determining the optimal material debt will involve the establishment of the
band parameters, depending on which we will determine the optimal speed that should provide the
maximum transported debt.
References
[1] Giurgiulescu, B., Bercea N., (2001). Modernizarea acţionărilor electrice la utilajele
tehnologice din carierele de ligni. pp 25-34, Editura Newest, Tg-Jiu, ISBN 973-8043-424-4.
[2] Kopchenova, N., Maron, I., (1984) Computational Mathematics - Worked Examples and
Problems with Elements of Theory, pp 123 - 130, Mir Publisher, Moskow, ISBN 77356389.
[3] Mihuţ, N., (2007), Contribuţii la îmbunătăţirea parametrilor tehnologici de transport ai
materialelor pe benzi, PhD thesis, University of Petrosani, Mechanical and Electrical Faculty.
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STATISTICAL METHODS AND THE RELIABILITY OF
PRODUCTION EQUIPMENTS
Dr.ing. Adrian Stere PARIS, Univ. Politehnica Bucharest, email: [email protected]
Abstract The paper offers a synthesis of some important applications in the aria of analysis and processing of
the reliability data of the production equipments documented by computer assisted specific statistical methods
and regression models.
Key words: reliability, statistical methods, production equipments
1. Introduction
Engineering education is traditionally concerned with teaching how manufactured
products work: the ways in which products fail, the effects of failure and aspects of design,
manufacture, maintenance and use which affect the likelihood of failure are not usually
taught. Engineering education is basically deterministic, and does not usually pay sufficient
attention to variation. Yet variability and chance play a vital role in determining the reliability
of most products. Understanding the laws of chance and the causes and effects of variability is
therefore necessary for the creation of reliable products and for the solution of problems of
unreliability [3].
Reliability of manufacturing equipment has a large impact on throughput and productivity.
Hitherto, attempts at modeling manufacturing equipment reliability has concentrated on the
use of analytical models or high-level simulation models. At the same time it is important to
have available different stastical methods for practical use. The expansion of software
applications, many of them free, render possible their use at large scale in engineering fields,
and particularly in manufacturing. Focus must be on reliability and not cost, because if
reliability starts to improve the cost will definitely go down and it cannot be the other way
around. There will be times that focusing on cost will hurt reliability, a lesson that we all
should reflect upon.
1. New statistical applications
One important problem in the study of different caharacteristics of production
equipments is to focus on the most importants. Discriminant analysis offers a possible way
in separation of groups: description of group separation, in which linear functions of the
variables (discriminatory functions) are used to describe or elucidate the differences between
two or more groups. The goals of descriptive discriminate analysis include identifying the
relative contribution of the p variables to the separation of the groups and the possibility to
find out the optimal plane on which the points can be projected to best illustrate the
configuration of the groups [6].
The Principal Component Analysis is a standard technique to reduce multivariate data sets
in a subspace of small dimension, frequently a tri-, respectively bivariate one. The number of
observable attributes gives the dimension of the initial representation space of the objects.
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As illustration - an application from the agricultural machinery, concerning selecting usual
dehusking equipment from Romanian market, with seven important mechanical and
technological properties: 4 agricultural equipments (objects), each of them having 7
attributes(Table1) [7].
Table 1. Bran finishers characteristics
Characteristics
C1
C2
C3
C4
C5
C6
C7
Mean yeld
capacity,
kg/h
Necessary
area for the
equipment,
m2
Installed
power, kW
Equipment
mass, kg
Dependability
coefficient
Air flow for
aspiration,
m3/min
Specific
loading
FTO
FT
30/60
FT
40/80
BRAN
BRUSH
687
275
550
650
0.93
1.064
1.73
1.322
4
2.2
5.5
4.4
285
320
650
530
0.92
0.85
0.88
0.83
5
3.5
4.5
5.5
85
24.5
27.5
175
Variables (axes F1 and F3: 69,55 %)
1
Var5
0.75
F3 (20,08 %)
0.5
Var3
Var1
0.25
Var2
Var4
0
Var6
-0.25
-0.5
Var7
-0.75
-1
-1
-0.75 -0.5 -0.25 0
0.25
F1 (49,47 %)
0.5
0.75
1
Figure 1. Correlation circle
Table 2. The eigenvalues of the model
Characteristics/
Factors
Eigenvalue
Variability (%)
Cumulative (%)
402
F1
3.463
49.471
49.471
F2
2.131
30.446
79.917
F3
1.406
20.083
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The results of the analysis are presented in tab. 2 and fig.1 [7].
In statistics, dependence refers to any statistical relationship between two random variables or
two sets of data. Correlation refers to any of a broad class of statistical relationships involving
dependence.Correlation, Covariance and their coefficients are frequently applied in the
study of field quality and reliability data. It is important to study the dependence between
deviations of working accuracy, namely deviations from cylindricity of the work piece in a
normal lathe, and time. In this respect, measurements were performed [2] on 47 pieces of
standard form, processed on the same type of normal lathes, recording the actual working
time for each machine, and the time since they were put into service on the considered
experiment. The evaluation of the correlation coefficient rendered possible the calculation of
the technological reliability [2].
3. Regression models
3.1. Regression of reliability data
The reliability community has become well experienced in fitting of survival distributions, the
use of design of experiments (DOE) and the associated general linear model (linear regression
and analysis of variance methods) approach to analysis. An opportunity to calculate the
regression curve for the reliability field data is the software CurveExpert, a comprehensive
curve fitting system for Windows. It employs a large number of regression models (both
linear and nonlinear) as well as various interpolation schemes to represent data.
Fig.2. Adapted beta hazard-rate function
As example for reliability regressions here is used the software LAB Fit [10], with the main
application Curve Fitting (nonlinear regression - least squares method, Levenberg-Marquardt
algorithm -, almost 500 functions at the library with one and two independent variables,
functions finder, option: write fitting function with up to 150 characters, 6 independent
variables and 10 parameters). An example for an adapted beta model for the hazard rate
function h(x), as representative reliability form, is presented in fig. 2:
]
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3.2. Technological reliability models
To emphasize the problem of accuracy for manufacturing equipments it was
introduced and developed the term of technological reliability [2, 5], that is quantitatively
defined at t moment as the probability of a manufacturing equipment (namely a machine-tool)
to maintain its working accuracy limits by the time t: this means to check the machine-tool
accuracy at different time moments and establish the corresponding function of technological
reliability, as example for a family of lathes [5]. The results are processed using multivariate
data analysis, especially correlation theory and regression analysis.
3.3. Logistic regression application
Logistic regression analysis (LRA) extends the techniques of multiple regression analysis to
research situations in which the outcome variable is categorical. Interesting developments in
the reliability field are the asset health reliability estimation based on condition data, the
prognostic algorithm for machine performance assessment and its application [8], etc. An
example (Fig. 3), uses bearing failure simulation data and experiment run-to-failure data[1].
Fig.3 Schematic diagram of machine degradation assessment model [1]
One-dimensional feature, namely kurtosis, is calculated initially and represents the
information of bearing from normal to failure condition. Failure degradation is calculated
using the LR method for case of simulated data and case of experiment data. The results are
regarded as target vectors of failure probability. RVM is used for training the run-to-failure
kurtosis data and target vectors of failure probability and predict the component. To evaluate
the training performance, root mean square error (RMSE) and correlation (R) are used [1].
4. Reliability and redundancy
Redundancy is a common approach to improve the reliability and availability of a system.
Adding redundancy increases the cost and complexity of a system design and with the high
reliability of modern electrical and mechanical components, many applications do not need
redundancy in order to be successful. However, if the cost of failure is high enough,
redundancy may be an attractive option [12n]. Against the above description, in the case of
manufacturing systems it must be considered the technological and production aspect. A new
concept, the manufacturing redundancy, should be introduced, to quantify the overlap of
manufacturing targets by more complex equipments, with multiple working possibilities.
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5. Conclusions
A few statistical methods of analysis and processing the reliability data are presented in the
paper. A concise overview of some statistical software with life data analysis is
complementary presented. New applications of more complex methods as Principal
Component Analysis and Logistic Regression Analysis are detailed. It is highlighting the
concepts of technological reliability and manufacturing redundancy, for real interest in
production development and reliability.
References
1. Caesarendra, W., Widodo, A., Yang, B., Application of relevance vector machine and
logistic regression for machine degradation assessment, Mechanical Systems and Signal
Processing 24 (2010) 1161–1171
7. Ionescu, A., Târcolea, C., Paris, A., S. - Metodă de stabilire a criteriului de calcul al
fiabilităţii tehnologice la maşinile-unelte. În: Construcţia de maşini, 1976, vol.23, nr.9, p.
485-487
3. O'Connor,P.,D.,T.,- Practical Reliability Engineering, 2002, ISBN: 978-0-470-84463-2
4n. Paris, A., S. - Models in mechanical reliability data- 3rd Symposyum „DURABILITY
AND RELIABILITY OF MECHANICAL SISTEMS‖ Univ C. Brancusi Tg. Jiu, mai 2010, In:
Fiability and Durability, no. 1(5)/2010, Ed.Academica , Tg. Jiu, ISSN 1844 – 640X p.81-86
5. Paris, A,. S., Târcolea, C., - Regression models applied to manufacturing systems, (2010),
Proceedings in Manufacturing Systems, Editura Academiei Române, vol.5, nr.4, pp. 249-253.
6. Târcolea, C., Paris, A., S.- Discriminant Analysis and Applied Regression The
International Conference of Differential Geometry and Dynamical BSG PROCEEDINGS 18,
(DGDS-2010) August 2010, Bucharest, Geometry Balkan Press, ISSN 1843-2654 (printed
version) pp. 221-226, ISSN 1843-2859 (online version), 2011, pp.95-100
7. Târcolea, C., Paris, A, S., Voicu, P.- Principal Component Analysis Applied to
Agricultural Equipments, Tarım Makinaları Bilimi Dergisi (Journal of Agricultural
Machinery Science) 2011, 7 (3) pp.305-308
8. Yan, J., Koc, M., Lee, J., A prognostic algorithm for machine performance assessment
and its application, (2004), Production Planning & Control, Vol. 15, No. 8, Dec., p796–801
9.*** http://www.ni.com/tutorials/ National Instruments Tutorial, Redundant System Basic
Concepts, Publish Date: Jan 11, 2008
10. *** http://zeus.df.ufcg.edu.br/labfit/
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STATISTICAL ANALYSIS OF SOME EXPERIMENTAL FATIGUE
TESTS RESULTS
Dr.ing. Adrian Stere PARIS, Univ. Politehnica Bucharest, email: [email protected]
Dr. ing. Gheorghe AMZA, Univ. Politehnica Bucharest, email: [email protected]
Ddr.ing.Claudiu BABIŞ, Univ. Politehnica Bucharest, email: [email protected]
Dr.ing.Dan Niţoi, Univ. Politehnica Bucharest email: [email protected]
Abstract.The paper details the results of processing the fatigue data experiments to find the regression function.
Application software for statistical processing like ANOVA and regression calculi are properly utilized, with
emphasis on popular software like MSExcel and CurveExpert.
Key words: welding fatigue experiments, ANOVA, regression
1.Introduction
For many practical applications and technologies an important step is the laboratory test
of every new constructive solution. Between many test procedures and methods a major
position is occupied by the fatigue check, especially by the welded joints. The paper basic
idea is that the convex fillet welds are more likely to crack and run out than the concave ones,
in case of fatigue tests. This is due to stress concentrators placed at the intersection between
the base and the filler material, which in case of convex fillet welds, because of the bead
shape which are higher than the ones in the case of the concave fillet, which welds smoothly
connected with base material.
2. Characteristics of the welded probes
The experiment used six welded samples as follows:
-three samples A1, A2, A3, with fillet welds (MAG welding), using full wire: the plates were
placed perpendicular between them (fillet weld): weld bead with convex shape;
-three samples D1; D2; D3 with fillet welds, (MAG welding), using routine cored tubular
wire, the plates also placed perpendicular between them: weld bead with concave shape.
The samples A1, A2, A3 and D1, D2, D3, were mechanically cut from two other bigger
welding samples, marked with A and D, with dimensions: 10X150x370 and a thickness of 10
mm.
We have chosen the base material of the both samples to be S 235 JR, with chemical
composition and mechanical properties indicated in NF EN 10028-2.
Filler material for the welding of the sample marked with A, with convex bead, is a full
wire symbolised G3Si1, according EN 440. On the other hand, the filler material for the
sample marked with D, with concave bead, is a routile core wired symbolised withT 42 2 P M
1 H5 – according to EN ISO - 17632-A.
The shielding gas in both cases, is gas M21 MIX ( Ar /CO2)– , according with EN 439.
The results obtained in case of fatigue tests of those six samples, are shown in table 1.
A first attempt in this case, of small samples of data (tab.1) - here the numbers of
cycles until breakage with the concave and convexes welds as columns (tab.2)- is to find the
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correlation coefficient, a possible orientation in the direction of correlation, very easy with the
MSExcel (tab.3) or other usual computer software. The calculus gives a value of 0.999989 of
the correlation coefficient r, suggesting a close relation between the two columns.
3. Fatigue test results and preliminary processing
Tab.1 Fatigue test results
3
4
5
6
Cycles
Freq.
[Hz]
Applied
Force ±Fi
[KN]
Nr. of
cycles to
breakage=
=time*freq.
±F1=±14
0.15
594
5940
A2
±F2=±9
±F3=±5.55100s
±F3‘=±7.52284s
0.15
1488
14880
0.05
7384
73840
±F1=±14
0.14
1850
18500
±F2=±9
±F3=±5.55100s
±F3=±7.511800s
0.1
3760
37600
0.04
16900
169000
A3
D1
D2
D3
Tab.2 Fatigue data
5940
14880
73840
Time
to
Amplit.
Probe
[mm]
breakage [s]
A1
10
2
Concave shape
1
Type
Convex shape
No.
Weld
bead
form
18500
37600
169000
Tab. 3Correlation calculus
Column
1
Column 1
Column
2
1
Column 2 0.999989
1
Next step is to test the null hypothesis. It is important to understand that the null
hypothesis can never be proven. A set of data can only reject a null hypothesis or fail to
reject it: if comparison of two groups reveals no statistically significant difference between
the two, it does not mean that there is no difference in reality. It only means that there is not
enough evidence to reject the null hypothesis (in other words, the experiment fails to reject
the null hypothesis) [2]. For the data (columns) in table 2 the null hypothesis in ANOVA is
that the means of the groups are equal. In other words, if the null hypothesis is true, it means
that these 2 groups are all from the same population (these 2 groups with their different
sample means simply represent 2 points on the same sampling distribution). If the hypothesis
is true, then the "between group variance" will be equal to the "within group variance." The
"between group variance" (or Mean Square due to Treatments or MSTR) is an estimate of the
variance of the population if the null hypothesis is true. We find it by calculating the variance
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between the 2 sample means, using the mean of ALL the observations as the estimate for the
population mean; the "within group variance" (or Mean Square Error or MSE) is an average
of the 2 actual sample variances found. If the null hypothesis is true, the "between group
variances" must be equal (close to) to the "within group variances"[4]. A one-way ANOVA
test (tab.4 and 5) was conducted using MSExcel (Anova: Two-Factor Without Replication).
Tab. 4 ANOVA summary
SUMMARY
Count
Sum
Average
Variance
Row 1
2
24440
12220
78876800
Row 2
2
52480
26240 258099200
Row 3
2
242840
121420 4.528E+09
Column 1
3
94660 31553.3333 1.361E+09
Column 2
3
225100 75033.3333 6.714E+09
Tab. 5 ANOVA results
ANOVA
Source of
Variation
SS
df
MS
F
P-value
F crit
Rows
1.412E+10
2 7060144267 6.9594988 0.125636
19
Columns
2.836E+09
1 2835765600 2.7953405 0.236502
18.51282051
Error
2.029E+09
2 1014461600
Total
1.898E+10
5
The amount of evidence required to accept that an event is unlikely to have arisen by
chance is known as the significance level or critical p-value: in traditional Fisherian statistical
hypothesis testing, the p-value is the probability of observing data at least as extreme as that
observed, given that the null hypothesis is true. If the obtained p-value is small then it can be
said either the null hypothesis is false or an unusual event has occurred [2].
The significance level α has popular levels of significance 10% (0.1), 5% (0.05), 1%
(0.01), 0.5% (0.005), and 0.1% (0.001). If a test of significance gives a p-value lower than the
significance level α, the null hypothesis is rejected [3]. Here it was chosen the most frequent
value of α, 0.05; the p-value from table 5 is higher then α and so the null hypothesis is
accepted. Addionally, Fcrit and F are compared using the F-test; the data from the table are in
a clear position: F> Fcrit, that demonstrates again that the null hypothesis is accepted: all the
six experimental values from table 2 can be considered a single sample and should be
processed together. Next, on this basis, is possible to look for a function for the dependency
between the force F and the number of cycles.
4. Regression and curve fitting for fatigue data
Regression is a conceptual technique for investigating functional relationship between
output and input decision variables of a manufacturing process and may be useful for process
data description, parameter estimation, and control [6,7]. Curve fitting is the construction
process of a curve, or mathematical function, which fits to the data points in the best way,
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possibly subject to constraints. An accessible opportunity to calculate the regression curve for
the fatigue experimental data is the curve fitting system CurveExpert [1]. The regression
results for the experimental fatigue data (tab.1) with CurveExpert software (Fig.1) gives the
logarithm fit as optimum solution (fig.2), with the mathematical form (fig.3) and the residuals
(fig.4).
Fig.1 Regression results
Fig.3 Logarithm fit expression
Fig.2 Logarithm fit
Fig.4 Logarithm fit residuals
6. Conclusions
A few elements of fatigue data processing are presented in the paper. Statistical
software is currently applied for data analysis. On the basis of ANOVA analysis the fatigue
data were grouped in a single sample, offering a bigger consistency for the function
determination. A regression function for the experimental data gave the best fit for the
logarithm function. A lot of other different functions were very close, offering a wide
spectrum for further investigation.
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5.References
1. http://curveexpert.software.informer.com/1.3/
2. http://en.wikipedia.org/wiki/Null_hypothesis
3. http://en.wikipedia.org/wiki/Significance_level
4. http://org.elon.edu/econ/sac/anova.htm
5. Paris, A., S. - Software applications for field reliability data, 4th Symposyum
„DURABILITY AND RELIABILITY OF MECHANICAL SISTEMS‖ Univ C. Brancusi, mai
2011, Fiability and Durability, no. 1(7)/2011, Ed.Acad., Tg. Jiu, ISSN 1844 – 640X p.75-80
6. Paris, A,. S., Târcolea, C., - Regression models applied to manufacturing systems, (2010),
Proceedings in Manufacturing Systems, Ed. Acad. Române, vol.5, nr.4, pp. 249-253.
7. Târcolea, C., Paris, A., S., , Discriminant Analysis and Applied Regression, UPB, BSG
Proceedings 18, DGDS-2010, Geometry Balkan Press, 2011, pp. 93-98
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A NUMERICAL METHOD USED FOR KINEMATIC SURVEY OF A
COMPLEX MECHANICAL SYSTEM WITH FOUR ROTATING RIGID
SOLIDS
PhD. Vladimir Dragoş TĂTARU University ―Valahia‖ of Târgovişte
Mircea Bogdan TĂTARU University of Oradea
Abstract: The paper presents a numerical method used for kinematical study of a complex mechanical system
consisting of four rigid solids, each one of them performing a rotating motion around an axis passing through a
fixed point. Each of the four solid rigid is connected to the frame by a joint. The four solid rigid are connected by
three rigid rods. The movement of this mechanical system presents a special appearance namely that during the
motion the system freezes (is blocking) at a certain moment.
Key words: mechanical system, numerical method, joint, movement blocking
1. Introduction
We will consider the mechanical system in the figure below consisting four rotating
rigid solids. Each rigid solid is bound by a joint to another element which is supposed to be
fixed called frame. The four rigid solids are interconnected by three rigid rods. The rigid solid
―1‖ is rotating around an axis passing through the fixed point ―O1‖. The angular speed of the
rigid solid ―1‖ is known. Further on we intend to study the mechanical system movement that
is the movements of the rigid solids ―1‖, ―2‖, ―3‖ and ―4‖ as a function of time.
y
A4
A1
1   6
A2
2
A3
6
4   6
3   6
4
1
2
1
3
O1
O4
O2
0,5 m
O3
0,25 m
x
0,5 m
Fig.1 Complex mechanical system with four rotating rigid solids
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2. Relationships determining between kinematical parameters of the rigid solids
that make up the system of rigid solids
Constraint relations between kinematical parameters of the rigid solids that make up the
system are obtained by imposing the condition that the distances between the two connection
points of each rod to be constant. Thus, imposing the condition that the distance between
points A1 and A2 to be constant we obtain:
x A2  x A1 2  y A2  y A1 2  A1A 2 2  constant
(1)
Doing similar with the pairs of points (A2, A3) and (A3, A4) we will now get the
followings constraint raltions:
x A3  x A2 2  y A3  y A2 2  A 2 A 3 2  constant
(2)
x A4
 x A3 2  y A4  y A3 2  A 3 A 4  2  constant
(3)
Under differential form the relations (1), (2) and (3) will be written as followings:
x A2


 x A1   x A2  x A1   y A2  y A1   y A2  y A1   0


x A3
 x A2   x A3  x A 2   y A3  y A 2   y A3  y A 2   0
x A4
 x A3   x A4  x A3   y A4  y A3   y A4  y A3   0

(4)
(5)

(6)
Sizes involved in relationships (4), (5) and (6) have the following expressions:
412
x A2  x O2  O 2 A 2  sin 2   2 
(7)
x A1  O1A1  sin 1  1 
(8)
y A2  O 2 A 2  cos2   2 
(9)
y A1  O1A1  cos1  1 
(10)
x A3  x O3  O 3 A 3  sin 3  3 
(11)
y A3  O 3 A 3  cos3  3 
(12)
x A4  x O4  O 4 A 4  sin 4   4 
(13)
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y A4  O 4 A 4  cos4   4 
(14)
x A2  x A1  x O2  O 2 A 2  sin 2   2   O1A1  sin 1  1 
(15)
y A2  y A1  O 2 A 2  cos2   2   O1A1  cos1  1 
(16)
x A3  x A2  x O3  O 3 A 3  sin 3  3   x O2  O 2 A 2  sin 2   2 
(17)
y A3  y A2  O 3 A 3  cos3  3   O 2 A 2  cos2   2 
(18)
x A4  x A3  x O3  O 3 A 3  sin 3  3   x O2  O 2 A 2  sin 2   2 
(19)
y A4  y A3  O 3 A 3  cos3  3   O 2 A 2  cos2   2 
(20)

x A2
 x A1   dx A2  x A1  dt  O1A1  cos1  1    1  O 2 A 2  cos2   2    2
y A2
 y A1   dy A2  y A1  dt  O1A1  sin 1  1    1  O 2 A 2  sin 2   2    2
x A3
 x A2   dx A3  x A2  dt  O 2 A 2  cos2   2    2  O 3 A 3  cos3   3    3
y A3
 y A2   dy A3  y A2  dt  O 2 A 2  sin 2   2    2  O 3 A 3  sin 3   3    3
x A4
 x A3   dx A4  x A3  dt  O 4 A 4  cos4   4    4  O 3 A 3  cos3   3    3 (25)
y A4
 y A3   dy A4  y A3  dt  O 4 A 4  sin 4   4    4  O 3 A 3  sin 3   3    3
(21)

(22)

(23)

(24)


(26)
In relations (21), (22), (23), (24), (25) and (26) the following notations are introduced:
413
O1A1  x  O1A1  sin 1  1 
(27)
O1A1  y  O1A1  cos1  1 
(28)
O 2 A 2  x  O 2 A 2  sin 2   2 
(29)
O 2 A 2  y  O 2 A 2  cos2   2 
(30)
O3 A 3  x  O3 A 3  sin 3  3 
(31)
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O 3 A 3  y  O 3 A 3  cos3  3 
(32)
O 4 A 4  x  O 4 A 4  sin 4   4 
(33)
O 4 A 4  y  O 4 A 4  cos4   4 
(34)
Using the above notations the relations (21), (22), (23), (24), (25) and (26) will be
written as followings:

x A2
 x A1   dx A2  x A1  dt  O1A1  y   1  O 2 A 2  y   2
y A2
 y A1   dy A2  y A1  dt  O1A1  x   1  O 2 A 2  x   2
x A3
 x A2   dx A3  x A 2  dt  O 2 A 2  y   2  O 3 A 3  y   3
y A3
 y A2   dy A3  y A2  dt  O 2 A 2  x   2  O 3 A 3  x   3
x A4
 x A3   dx A4  x A3  dt  O 4 A 4  y   4  O 3 A 3  y   3
y A4
 y A3   dy A4  y A3  dt  O 4 A 4  x   4  O 3 A 3  x   3
(35)

(36)

(37)

(38)

(39)

(40)
2.1 Relationship determining between kinematical parameters describing the
motion of rigid solids ―1‖ and ―2‖.
Replacing relations (35) and (36) in relation (4) we obtain the relation between
kinematical parameters describing the motion of rigid solids (1) and (2).
x A2
 x A1 
y A2
T
 y A1   A   1  2   0
(41)
In relation (41) the marix [A] has the following mathematical expression:
 O1A1  y  O 2 A 2  y 
A  
O 2 A 2  x 
 O1A1  x
414
(42)
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2.2 Relationship determining between kinematical parameters describing the
motion of rigid solids ―2‖ and ―3‖.
Replacing relations (37) and (38) in relation (5) we obtain the relation between
kinematical parameters describing the motion of rigid solids (2) and (3):
x A3  x A2  y A3  y A2   B   2
T
 3   0
(43)
In relation (43) the marix [B] has the following mathematical expression:
O 3 A 3  y 
 O A 
B   2 2 y

  O 2 A 2  x  O 3 A 3  x 
(44)
2.3 Relationship determining between kinematical parameters describing the
motion of rigid solids ―3‖ and ―4‖.
Replacing relations (39) and (40) in relation (6) we obtain the relation between
kinematical parameters describing the motion of rigid solids (3) and (4):
x A4
 x A3 
y A4
 y A3   C   3
T
 4   0
(45)
In relation (45) the marix [C] has the following mathematical expression:
 O 4 A 4  y 
 O A 
C   3 3 y

  O 3 A 3  x  O 4 A 4  x 
(46)
3. Differential equation determining describing the motion of the rigid solid ―1‖
Rigid solid ―1‖ rotates uniformly around the axis passing through the fixed point O1. The
equation of motion for the rigid solid will be written as follows:
 1  1  constant
(47)
In relation (47) angular speed ―ω1‖ is known with an arbitrary value.
4. Differential equation determining describing the motion of the mechanical
system
Relations (41), (43), (45) and (47) form a system of four first order differential equations
with four unknown quantities which can be solved using numerical integration methods.
Solving this system of differential equations we obtain the values of the four angular
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displacements β1, β2, β3 şi β4 from initial time to the blocking time.
Variation in relation to time of the four angular displacements values is represented in
the figure below (fig.2).
If you wish to determine the size projections lengths of the three rods A1A2, A2A3 and
A3A4 on the axes Ox and Oy then the differential equations expressed by the relations (35),
(36), (37), (38), (39) şi (40) will be added to the differential equations system formed of
differential equations (41), (43), (45) şi (47). In this way we will get a ten first order
differential equations system with ten unknowns which can be solved using numerical
integration methods and we will obtain the values of the unknowns as function of time.
Measurements values expressed by relations (27), (28), (29), (30), (31), (32), (33) and
(34) can also be determined.
0.25
 1=1,97324[rad]
0.1
-0.25
 2[rad]
 1[rad]
0.2
0.15
0
-1
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
time [seconds]
0.2
0.15
 3=1,45525[rad]
0.5
 4[rad]
3
 [rad]
0
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
time [seconds]
2
1
 2=-0,726504[rad]
-0.75
0.05
1.5
-0.5
0.1
 4=0,1695[rad]
0.05
0
0
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
time [seconds]
-0.05
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
time [seconds]
Fig.2 Angular displacements variation as a function of time
5. Conclusions
This paper presents the kinematical survey of a complex mechanical system consisting
of four rotating rigid solids linked by a joint to the frame and interconnected by three rigid
rods. The three rigid rods introduce three constraint relations between kinematical parameters
of the four rigid solids describing the motion of the motion of the mechanical system. Thus
we can say that the mechanical system has one degree of freedom.
The motion of the mechanical system shown in the paper presents a more special aspect
namely that the system is blocking at a certain moment.
The numerical method presented in the paper can be used for kinematical survey of any
other mechanical system including a mechanism.
Mechanical system whose kinematical survey was performed in the paper is just one
example to illustrate the application of the method.
References
1. Mangeron D., Irimiciuc N., Mecanica rigidelor cu aplicatii in inginerie Vol I, II,,
Editura Tehnică, Bucureşti 1981
2. Vâlcovici V. si altii Mecanica teoretica, Editura Tehnica 1965
3. Voinea R. si altii, Mecanica, Editura Didactica si Pedagogica Bucuresti 1975
416
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Editura “Academica Brâncuşi” , Târgu Jiu, ISSN 1844 – 640X
A NUMERICAL METHOD USED FOR KINEMATIC SURVEY OF A
COMPLEX MECHANICAL SYSTEM WITH TWO ROTATING RIGID
SOLIDS AND TWO RIGID SOLIDS IN TRANSLATIONAL MOTION
PhD. Vladimir Dragoş TĂTARU University ,,Valahia‖ of Târgovişte
Mircea Bogdan TĂTARU University of Oradea
Abstract: The paper presents a numerical method used for kinematical survey of a complex mechanical system
consisting of four rigid solids of which two perform a rotational motion and the other two rigid solids in
translational motion. The rigid solids performing a rotational motion are connected to the frame by a joint and
the rigid solids performing a translational motion are connected to the frame by slides. The rigid solids are
interconnected by rigid solids rods. The motion of this mechanical system presents a peculiarity namely that the
system is blocking at a certain moment.
Key words: mechanical system, numerical method, joint, slide, motion blocking
1. Introduction
We will consider the mechanical system in the figure below consisting four rigid solids.
Two of them are bound by a joint to another element which is supposed to be fixed called
frame and the other two are connected to the frame by slides. The four rigid solids are
interconnected by three rigid rods. The rigid solid ―1‖ is rotating around an axis passing
through the fixed point ―O1‖. The angular speed of the rigid solid ―1‖ is known. Further on we
intend to study the mechanical system movement that is the movements of the rigid solids
―1‖, ―2‖, ―3‖ and ―4‖ as a function of time.
y
A3
A1
O2≡A2
O4≡A4
1   6
3   6
4
1
3
\
3
2
1
O1
0,1 m
0,1 m
q2
0,5 m
0,25 m
q4
O3
x
0,5 m
Fig.1 Complex mechanical system with rotating rigid solids and two rigid solids in translational motion
417
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Editura “Academica Brâncuşi” , Târgu Jiu, ISSN 1844 – 640X
2. Relationships determining between kinematical parameters of the rigid solids
that make up the system of rigid solids
Constraint relations between kinematical parameters of the rigid solids that make up the
system are obtained by imposing the condition that the distances between the two connection
points of each rod to be constant. Thus, imposing the condition that the distance between
points A1 and A2 to be constant we obtain:
x A2
 x A1 2  y A2  y A1 2  A1A 2  2  constant
(1)
Doing similar with the pairs of points (A2, A3) and (A3, A4) we will now get the
followings constraint raltions:
x A3
 x A2 2  y A3  y A2 2  A 2 A 3  2  constant
(2)
x A4
 x A3 2  y A4  y A3 2  A 3 A 4  2  constant
(3)
Under differential form the relations (1), (2) and (3) will be written as followings:
x A2


 x A1   x A2  x A1   y A2  y A1   y A2  y A1   0


x A3
 x A2   x A3  x A 2   y A3  y A 2   y A3  y A 2   0
x A4
 x A3   x A4  x A3   y A4  y A3   y A4  y A3   0

(4)
(5)

(6)
Sizes involved in relationships (4), (5) and (6) have the following expressions:
418
x A 2  x O2  q 2
(7)
x A1  O1A1  sin 1  1 
(8)
y A2  y O2  constant
(9)
y A1  O1A1  cos1  1 
(10)
x A 4  x O4  q 4
(11)
x A3  x O3  O 3 A 3  sin 3  3 
(12)
y A4  y O4  constant
(13)
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Editura “Academica Brâncuşi” , Târgu Jiu, ISSN 1844 – 640X
y A3  O 3 A 3  cos3  3 
(14)
x A2  x A1  x O2  q 2  O1A1  sin 1  1 
(15)
y A2  y A1  y O2  O1A1  cos1  1 
(16)
x A3  x A2  x O3  O 3 A 3  sin 3  3   x O2  q 2
(17)
y A3  y A2  O 3 A 3  cos3  3   y O2
(18)
x A4  x A3  x O4  q 4  x O3  O 3 A 3  sin 3  3 
(19)
y A4  y A3  y O4  O 3 A 3  cos3  3 
(20)

x A2
 x A1   dx A2  x A1  dt  q 2  O1A1  cos1  1    1
y A2
 y A1   dy A2  y A1  dt  O1A1  sin 1  1    1
(21)

(22)

x A3
 x A2   dx A3  x A 2  dt  q 2  O 3 A 3  cos3   3    3
y A3
 y A2   dy A3  y A2  dt  O 3 A 3  sin 3   3    3
(23)

(24)

x A4
 x A3   dx A4  x A3  dt  q 4  O 3 A 3  cos3   3    3
y A4
 y A3   dy A4  y A3  dt  O 3 A 3  sin 3   3    3
(25)

(26)
In relations (21), (22), (23), (24), (25) and (26) the following notations are introduced:
419
O1A1  x  O1A1  sin 1  1 
(27)
O1A1  y  O1A1  cos1  1 
(28)
O3 A 3  x  O3 A 3  sin 3  3 
(29)
O 3 A 3  y  O 3 A 3  cos3  3 
(30)
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Editura “Academica Brâncuşi” , Târgu Jiu, ISSN 1844 – 640X
Using the above notations the relations (21), (22), (23), (24), (25) and (26) will be
written as followings:

x A2
 x A1   dx A2  x A1  dt  q 2  O1A1  y   1
y A2
 y A1   dy A2  y A1  dt  O1A1  x   1
x A3
 x A2   dx A3  x A 2  dt  q 2  O 3 A 3  y   3
y A3
 y A2   dy A3  y A2  dt  O 3 A 3  x  3
(31)

(32)

(33)

(34)

x A4
 x A3   dx A4  x A3  dt  q 4  O 3 A 3  y   3
y A4
 y A3   dy A4  y A3  dt  O 3 A 3  x   3
(35)

(36)
2.1 Relationship determining between kinematical parameters describing the
motion of rigid solids ―1‖ and ―2‖.
Replacing relations (31) and (32) in relation (4) we obtain the relation between
kinematical parameters describing the motion of rigid solids (1) and (2).
x A2
 x A1 
y A2
T
 y A1   A   1 q 2   0
(37)
In relation (37) the marix [A] has the following mathematical expression:
 O1A1  y 1
A  
0
 O1A1  x
(38)
2.2 Relationship determining between kinematical parameters describing the
motion of rigid solids ―2‖ and ―3‖.
Replacing relations (33) and (34) in relation (5) we obtain the relation between
kinematical parameters describing the motion of rigid solids (2) and (3):
x A3  x A2  y A3  y A2   B   3
420
q 2   0
T
(39)
Fiabilitate si Durabilitate - Fiability & Durability Supplement no 1/ 2012
Editura “Academica Brâncuşi” , Târgu Jiu, ISSN 1844 – 640X
In relation (39) the marix [B] has the following mathematical expression:
 O 3 A 3  y  1
B  

  O 3 A 3  x 0 
(40)
2.3 Relationship determining between kinematical parameters describing the
motion of rigid solids ―3‖ and ―4‖.
Replacing relations (35) and (36) in relation (6) we obtain the relation between
kinematical parameters describing the motion of rigid solids (3) and (4):
x A4
 x A3 
y A4
 y A3   C   3
T
 4   0
(41)
In relation (41) the marix [C] has the following mathematical expression:
1
O A 
C   3 3 y 
O 3 A 3  x 0
(42)
3. Differential equation determining describing the motion of the rigid solid ―1‖
Rigid solid ―1‖ rotates uniformly around the axis passing through the fixed point O1. The
equation of motion for the rigid solid will be written as follows:
 1  1  constant
(43)
In relation (43) angular speed ―ω1‖ is known with an arbitrary value.
4. Differential equation determining describing the motion of the mechanical
system
Relations (37), (39), (41) and (43) form a system of four first order differential equations
with four unknown quantities which can be solved using numerical integration methods.
Solving this system of differential equations we obtain the values of the four angular
displacements β1, β2, β3 şi β4 from initial time to the blocking time. Variation in relation to
time of the four angular displacements values is represented in the figure below (fig.2).
If you wish to determine the size projections lengths of the three rods A1A2, A2A3 and
A3A4 on the axes Ox and Oy then the differential equations expressed by the relations (31),
(32), (33), (34), (35) şi (36) will be added to the differential equations system formed of
differential equations (37), (39), (41) şi (43). In this way we will get a ten first order
differential equations system with ten unknown which can be solved using numerical
integration methods and we will obtain the values of the unknowns as function of time.
Measurements values expressed by relations (27), (28), (29) and (30) can also be
determined. The relations (27), (28), (29) and (30) can be written under the following form:
421
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Editura “Academica Brâncuşi” , Târgu Jiu, ISSN 1844 – 640X

O1A1  x  O1A1  cos1  1    1  O1A1  y   1
(44)

O1A1  y  O1A1  sin 1  1    1  O1A1  x   1
(45)

O 3 A 3  x  O 3 A 3  cos3   3    3  O 3 A 3  y   3
(46)

O 3 A 3  y  O 3 A 3  sin 3   3    3  O 3 A 3  x   3
(47)
Taking account of relations (44), (45), (46) and (47) we obtain a system of fourteen
differential equations with fourteen unknowns which can be solved using numerical
integration methods.
2.5
1=2.019105512163534 [rad]
q2[meters]
1[rad]
2
1.5
0.2
1
0.5
0
0
0.25
0.5
0.75
1
1.25
0.1
0
-0.1
-0.2
0
1.5
q2= -0.1663183192683230 [m]
0.25
time [seconds]
q4[meters]
3[rad]
1
1.25
1.5
0.2
3=0.9348690074464843 [rad]
0
-0.5
-1
0
0.75
time [seconds]
1
0.5
0.5
0.25
0.5
0.75
time [seconds]
1
1.25
1.5
0.1
0
-0.1
-0.2
0
q4=-0.1781277608418223 [m]
0.25
0.5
0.75
1
1.25
1.5
time [seconds]
Fig.2 Angular displacements variation as a function of time
5. Conclusions
This paper presents the kinematical survey of a complex mechanical system consisting
of four rigid solids. Two of them are linked by a joint to the frame and the other two are
linked to the frame by slides. The four rigid solids are interconnected by three rigid rods. The
three rigid rods introduce three constraint relations between four rigid solids kinematical
parameters describing the motion of the mechanical system. Thus we can say that the
mechanical system has one degree of freedom.
The motion of the mechanical system shown in the paper presents a more special aspect
namely that the system is blocking at a certain moment.
The numerical method presented in the paper can be used for kinematical survey of any
other mechanical system including a mechanism.
Mechanical system whose kinematical survey was performed in the paper is just one
example to illustrate the application of the method.
References
1. Mangeron D., Irimiciuc N., Mecanica rigidelor cu aplicatii in inginerie Vol I, II,,
Editura Tehnică, Bucureşti 1981
2. Vâlcovici V. si altii Mecanica teoretica, Editura Tehnica 1965
3. Voinea R. si altii, Mecanica, Editura Didactica si Pedagogica Bucuresti 1975
422
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Editura “Academica Brâncuşi” , Târgu Jiu, ISSN 1844 – 640X
A NEW REPRESENTATION RESULT FOR STOCHASTIC
DIFFERENTIAL EQUATIONS WITH INFINITE MARKOV JUMPS
AND MULTIPLICATIVE NOISE
V.M. UNGUREANU, Constantin Brâncuşi University, Tg-Jiu, ROMANIA
Abstract. In this paper we give a new representation of the conditional mean square of the solutions for a class
of stochastic differential linear equations with infinite Markov jumps (SDELMs) and multiplicative noise. The
obtained result is related to the solutions of two Lyapunov type differential equations defined on ordered Banach
spaces of sequences of bounded operators.
Keywords: seqences, matrix, subspace;
1. INTRODUCTION
In the last decades, the SDELMs with and without multiplicative noise have attracted the
interest of the researchers [5], [6] and led to new applications in modern queuing network
theory [4] or in the study of safety-critical and high integrity systems (see [1] and the
references therein.) As in the discrete time-case (see for e.g [9], [8]), the representation of the
conditional mean square of the solutions for SDELMs play an important role in studying
different stability and optimal control problems ([8], [5], [6], [1]). So, in this paper we establish
a new representation result based on the solution properties of some Lyapunov type equations
associated with the discussed SDELMs.
2. NOTATIONS
Let Z be an interval of integers, which may be finite or infinite. Let R n be the n dimensional Euclidian space of real numbers and let M nm R  be the real normed linear
space of all n  m matrices with real entries; if m  n we will write M n R  instead of
M nn R  . Let l MZ nm R  be the space of all Z -sequences g  {g i   M nm R }iZ with the
property that
l
Z
M n m  R 
g
Z
: supiZ gi    . It can be shown by using a standard procedure that
is a real Banach space when endowed with the usual term-wise addition, the real
scalar multiplication and the norm
sequences
. Z . The Banach subspace of l MZ n R  formed by all
g  {g i }iZ of symmetric matrices g i  , i  Z will be denoted by l SZn R  . An
element g  l MZ n R  is said to be positive, and we write g  0 , iff g i  is a nonnegative
matrix (
g i   0 ) for all
i  Z . If
  ...I n , I n , I n ,... is an element of l
423
Z
M n R 
In
is the identity matrix from
M n R  , then
.
Fiabilitate si Durabilitate - Fiability & Durability Supplement no 1/ 2012
Editura “Academica Brâncuşi” , Târgu Jiu, ISSN 1844 – 640X
Let us consider the linear subspace H nZ of l MZ n R  formed by all sequences {Pi }iZ
with the property
 TrP  P   
P2
T
i
A M n R  and the the superscript
H nZ
i
, where
TrA
T
denotes the transpose. It is not difficult to see that
is a Hilbert space with the inner product
Z
n
Analogously, we define N , the linear subspace of l
with the property
is the trace of the matrix
iZ
Z
M n R 
D, F
2
 TrFiT Di  , D, F  H nZ .
iZ
formed by all sequences {Pi }iZ
P 1   Tr PiT Pi    . (We recall that, if A M n R  is a nonnegative
iZ
matrix, then A is the unique nonnegative matrix defined by A 
way it follows that N nZ is a Banach space.
Moreover,
since
there
are
n1 , n2  0
A A ). By a standard
such
that
n1Tr X T X  TrX T X  n2Tr X T X
for all X  M n R  it follows that the linear spaces N nZ and H nZ coincide. In what follows
 
we will denote by  the adjoint operator of any operator   L H nZ .
Let T  0 . If B is an arbitrary Banach space, then we denote by C (0, T , B) the
space of all mappings G : 0, T   B that are continuous. Also C 1 (0, T , B) denotes the
subspace of C (0, T , B) of all continuously differentiable mappings G on 0, T  (i.e. G
0, T  and G  is continuous on 0, T  ). The product
is differentiable on
Z
of any two functions
and
t  J  Gt  X t   l M n p R 
G : J  L l MZ n R  , l MZ n p R 

X : J  l MZ n R 
will be often denoted shortly

Gt , X t  . In this case we will write
Gt , X t i  for the i -th component of Gt , X t  .
Let wt   w1 t , w2 t ,.., wr t , t  R  ( R   {t  R, t  0} ) be a standard r
dimensional Wiener process (see [3]) on a complete probability space (, F, P) . For each
t  0 , we denote by Ft the smallest  -algebra which contains all sets M  F with
P(M )  0 and with respect to which all random vectors {w( s)}st are measurable. Let
 t , t  R  be a right continuous, homogeneous Markov chain with the state space Z and a
stationary standard transition probability matrix function {Pt i, j }i , jZ defined by
  t  oij t , i  j
Pt i, j   P t     j |     i    ij
,


1


t

o
t
,
i

j
ii
ii

for all 0   . Here   ij i , jZ , is the infinitesimal matrix of the Markov process; it is
known that ij  0 for i  j and ii  0 . We also assume that:
1.  t  is conservative and stable, i.e. there is c  R  such that
i Z ;
2. there is c1  R  such that
 ij  ii  c for all
jZ, j i
 ij  c1 for all i  Z ;
jZ, j i
3. the  -algebras Ft and G t     , 0    t  are independent for every t  0.
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2. MAIN RESULTS
We consider the class of stochastic differential equations
r
dxt   A0 t , t  xt  dt   Ak t , t  xt  dwk t , t  t 0 , xt 0   x0  R n ,


(1)
k 1
where Ak  Cb R  , lMZ n R  , Ak t   {Ak t , i }iZ for all k  0,1.., r .
It is known that under the above hypotheses there is a unique continuous solution
x(t )  x(t , t 0 , x) , t  t 0 , of (1). Let us denote A(t , i)  A0 (t , i)  2ii I n and, for all i  Z and


X  l SZn R  and t  R  , we define the linear operators on L lSZn R  :
 1 t , X i    AkT (t , i ) X i  Ak (t , i )   ij X  j ,
r
k 1
jZ, j  i
1 t , X i    Ak (t , i ) X i  AkT (t , i )    ji X  j ,
r
k 1
jZ, j  i
Gt , X i   A (t , i) X (i)  X (i) A(t , i)  1 t , X i 
T
(2)
Gt , Y i   A(t , i)Y (i)  Y (i) A (t , i)  1 t , Y i .
T

It is not difficult to see that Gt , Gt   L l
Z
Sn R 

(3)
and their restrictions to H
Z
n
Z
n
and N ,
respectively, remain linear and bounded operators. In addition G, G  Cb (R  , B) , where


B  L lSZn R  , LH nZ , LN nZ  . It is not difficult to see that the adjoint operator of Gt  (as a
 
 
linear and bounded operator from L H nZ ) is exactly the restriction of G t  to L H nZ .
We associate with (1) the following Lyapunov equations:
d
(4)
X t , i   Gt , X t i   0
dt
d
(5)
Y t , i   Gt , Y t i .
dt
The equation (4) with the initial condition X s   D  l SZn R  has a unique solution

X t , s; D  not U t , s D  C 1 ([s, ), l SZn R  ) [7]. The mapping t , s   U t , s  L lSZn R 
an evolution operator on l SZn R  having the property
U t , s 
s

is
 U t , s Gs  [7]. It is called the
evolution operator generated by G  Cb (R  , l SZn R  ) . Let D  H nZ . An easy computation
shows that U  t 0 , t D  is the unique solution of (5) with the final condition Y t 0   D .
Now let {V t , s }0st the evolution operator generated by the mapping G  Cb (R  , l SZn R  )
 
(see [7]). Since G  Cb (R  , L H nZ ) , it follows that V t , s D  U  t0 , t D for all D  H nZ
, by the uniqueness of the solution. Analogously we can deduce that V t , s D   N nZ for all
D  N nZ .
Further we consider the element of H nZ  N nZ defined by
i,x
i,x
P  j   0 , if i  j and
P  j   x  x . We get the following.
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Lemma 1. For all 0  s  t , i  Z and x  R n we have
U t , s  i  x, x  V t , s i , x P 
1
.
 I , i  m,
Proof. Let m  H nZ , m  N  , defined by m i    n
. Obviously
 0, i  m,
1  2  ...  m  ...   . By Lemma 2 from [9]we have
V t , s i , x P   lim m,V t , s i , x P  .
m
1
2
From (5), it follows that V t , s   i , x P   U s, t   i , x P  and therefore

lim m,V t , s  i , x P   lim m,U  s, t  i , x P 
m
2
m
2
 lim  Tr  i , x P  j U s, t m j   Tr  i , x P i U s, t    U t , s  i  x, x .
m
jZ
The conclusion follows.
For all H  l SZn R  and 0  t 0  s we define the mapping T s, t 0  : l SZn R   l SZn R  ,


T s, t 0 H i  x, x  E H  s  xs , xs  | (t0 )i , where i  Z


x  R n . Note that
and


T s,t 0  is well defined, because sup E H  s  xs , xs  | (t0 )i  H Z sup E xs  | (t0 )i and


E xs  | (t0 )i  K , where K
2
iZ
iZ
2
does not depends on i . (The last inequality follows by
arguing as for the proof of Theorem 37 from [3]). Moreover, it follows easily that T s,t 0  is
a linear and bounded operator on l SZn R  and T s, t 0 H   0 for all H  l SZn R  , H  0 (we
will say that T s,t 0  is a positive operator).
Theorem 1. For all 0  s  t , i  Z and x  R n we have


E xs  | (t0 )i  T s, t0  i  x, x  V s, t0  i , x P  .
2
1
Proof. Applying Ito's formula (see Theorem 37 in [3]) for the function
vt , x, i   H i  x, x , t  R, x  R n and i  Z and the stochastic process x(t , t 0 , x) we get
E[ H  s  xs , xs  | (t0 )i ]  H i  x0 , x0 
s
r
t0
k 1
E[  2 H  t  xt , A0 t , t  xt    AkT t , t  H ( t ) Ak t , t  xt , xt  
  H  t  xt , xt   t  j | (t0 )i ]dt.
jZ
s
Hence T s, t 0 H i  x, x  H i  x, x   T t , t 0 [ A0T t  H  HA0 t   1 t , H i ]x, x dt .
t0
Differentiating with respect to s we get
426
dT  s , t0 
ds
 T s, t 0 Gs , T t 0 , t 0 H   H . If
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H , D  H nZ we have
d T   s , t0  D , H
ds
2
 Gs T  s, t 0 D , H , T  t 0 , t 0 D   D and we deduce
that T  s, t 0   V t , s  . On the other hand, let DmmN  lSZn R  be an increasing and
bounded sequence with Di  x   lim m Dmi  x , for all i  Z and x  H . Since
T s,t 0  is a positive operator, it follows that T s, t 0  Dm  T s, t 0  Dm  1, m  N . Thus,
the definition of T s, t 0  Dm and the Monotone convergence theorem imply that
lim T s, t0 Dmi  x, x  T s, t0 D i  x, x
m
for all i  Z and x  R n . Now it is clear that T s, t 0 Dmi  converges to T s, t 0 Di 
for all i  Z . Replacing Dm and D with  m and  , respectively, and using Lemma 1,
we get successively T s, t 0  i  x, x  lim T s, t 0 mi  x, x  V s, t 0   i , x P  .
m
1
The conclusion follows.
REFERENCES
[1] O. L.V. Costa , W. L. de Paulo, Indefinite quadratic with linear costs optimal control of
Markov jump with multiplicative noise systems, Automatica 43 (2007) 587 -- 597.
[2] E.F. Costa, J.B.R. do Val, On the detectability and observability of discrete-time Markov
jump linear systems, Systems & Control Letters 44 (2001) 135--145.
[3] V. Dragan, T. Morozan, A. Stoica, Mathematical Methods in Robust Control of Linear
Stochastic Systems, Springer, 2006.
[4] H. Daduna, Queueing Networks with Discrete Time Scale, Lecture Notes in Computer
Science,Vol. 2046, Springer, 2001.
[5] Fragoso, M. D., and Baczynski, J., Optimal Control for Continuous Time LQ - Problems
with Infinite Markov Jump Parameters, SIAM Journal on Control and Optimization,
40(2001), 270-297.
[6] Fragoso, M.D. and J. Baczynski, Lyapunov Coupled Equations for Continuous time
Infinite Markov Jump Linear Systems , Journal Math. Analysis and Applications, 274
(2002), 319-335.
[7] A. Pazy , Semigroups of linear operators and applications to partial differential
equations, Applied Mathematical Sciences 44, Springer- Verlag, Berlin, New -York,
1983.
[8] V. M. Ungureanu, Representations of mild solutions of time-varying linear stochastic
equations and the exponential stability of periodic systems, Electronic Journal of
Qualitative Theory of Differential Equations, 2004, No. 4, 1-22.
[9] V.M. Ungureanu, V. Dragan, Stability of discrete-time positive evolution operators on
ordered Banach spaces and applications, submitted to J. Differ. Eq. Appl.
[9] V.M. Ungureanu, V. Dragan, Stability of discrete-time positive evolution operators on
ordered Banach spaces and applications, submitted to J. Differ. Eq. Appl.
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FLEXIBLE SERVICE BINDING IN DISTRIBUTED AUTOMATION
AND CONTROL SYSTEM
Prof.dr.ing.Cristiana VOICAN,University Politechnic of
Bucharest,[email protected]
Prof.univ.dr.eng.Constantin STANESCU,University Politechnic of
Bucharest,[email protected]
Abstract.Particular emphasis was placed on the dynamic lease-based binding of services which on the one
hand provides flexible and loose coupling of system components but on the other hand has to ensure reliable
communication and cooperation. The guidelines were applied to the experimental implementation of a
manufacturing cell control system using a real-time version of the Java Runtime Environment.
The Device Profi.le for Web Services (DPWS) was used as basic infrastructure technology. Test and evaluation
were performed under distributed simulation of technical processes and devices
Keywords: service, interface, structure
1. INTRODUCTION
One of the key features of service-orientation is the use of loosely coupled
components. As all devices, sensors and actuators provide a service interface the coupling of
components can correspond to the flexible binding of services.
This flexible binding of services demands for service description, discovery and
selection, and service association and linking mechanisms.
The service description subsumes three basic parts:
• Type and interface definition,
• Binding and communication information,
• Functional properties.
The type and interface definition of a service specifies the methods and parameters
associated with a specific service type. All services that comply with a specific service type
offer the same interface.
The binding and communication information contains information about the actual
communication endpoints and the basic communication mechanisms, such as IP addresses
and ports, and application protocol regulations. At last, the functional properties complete
the information on devices in the automation system. They e.g. include, which sensor is
attached to which conveyer and what is the exact position.
The service description is the basis for the discovery and selection of matching
services by the automation process and control services. In our system, the discovery and
description phase are based on DPWS technology and thus adhere to the WS-Discovery and
WS-Transfer (for metadata exchange) standards.
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2.. FLEXIBLE
SERVICE BINDING
The association and linking of matching services with a particular client is handled by
our lease based binding approach to meet the requirements of a flexible but also stable way
for dealing with loosely coupled services in the domain of industrial automation.
The notion of a lease was first introduced by and was used to provide an efficient,
fault tolerant way for using file caches in distributed environments. Further on leases were
used in Jini to grant clients access to network services.
In the case a client wants to use a particular service, it issues a lease-request which
contains a duration for which the client wants the lease to be valid.
The service responds with a denial or a grant. A granted lease is valid only for the duration.
Thus the client has to request another lease for service use after the current lease has
expired or may prolong it before its valid duration has passed.
In automation systems a client usually uses a set of services (sensors, actuators, and
controllers) and has to allocate a suitable ensemble.
Therefore we extend the lease model by adding support for the atomic allocation of
service ensembles.
The atomicity property guarantees that a client either is granted the leases for all
requested services or it gets no lease at all. This atomicity is achieved by a 2-phase algorithm,
which is similar to the 2-phase-commit protocol. It is a lease granting algorithm with explicit
reservations (cf. Figure 1).
During the coupling phase the client asks the suitable services for reservations.
Reservations are binding for a short duration. If all services positively respond, the client
submits lease-requests that yield to valid usage leases.
If at least one service cannot satisfy the reservation request, the client cancels all
other reservations.
After the coupling phase is completed, the interaction of coupled components starts.
The client process configures and initializes the services and finally starts production (cf.
Figure 2).
When the leases are about to expire, the client either issues a prolongation request to
extend the production phase or stops the services and performs cleanup operations.
The prolongation of existing leases uses the same 2-phase algorithm as used at initial lease
creation. In the decoupling phase the expired leases are fairly released and deleted.
3. APPLICATION EXAMPLE
The service-oriented control software presented so far was experientially evaluated
for an example industrial automation setup. The example system and the tested applications
scenarios are presented in this section.
3.1. EXAMPLE STRUCTURE
The structure of our evaluation example is depicted in Figure 6. The work pieces
enter the system through conveyer conv1 and conv2.
Both conveyers are located next
to a rotary disk, which is able to collect work pieces from either conv1 or conv2 by rotating
the disk and using the conveyer element conv3 on top of the disk.
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This conveyer transports the work pieces to conveyer conv4 which in turn moves
them through the lacquer machine.
After being painted by the lacquer machine, the work pieces are checked by a laser sensor.
Inaccurate pieces are pushed into a disposal box by a pusher. Proper items are moved out of
the system to the next work station. The devices and sensors (not depicted) are exporting
services as described in section.
The logical control of the conveyers is implemented using a PID controlling
algorithm which could be differently parameterized for evaluation purposes.
Figure 1. Lease lifecycle
Figure 2. Leases and production
3.2. APPLICATION SCENARIOS
The example system was evaluated using different application scenarios. The
scenarios use different service hierarchies and thus model different levels of control in the
application process.
The first scenario comprises the following process:
1. Work pieces are picked up from conv1 or conv2.
2. The rotary disk and conv3 transport the work pieces to conv4.
3. The lacquer machine paints the work pieces.
4. The inaccurate work pieces are detected and pushed into the disposal box.
5. The acceptable work pieces are moved out of the system.
The service hierarchy for this application process is depicted in Figure 4. The
application process uses six different control services (light gray), each responsible for a
specific part of the example system. The control services themselves are using a set of sensor
and actuator service interfaces to interact with the hardware at technical process level (dark
grey). In contrast, the rotdisk control service for controlling the rotary disk and conv3 on top
of the disk as a whole uses the control services of the single components. It implements an
algorithm for the balanced use of the two attached input conveyers.
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The second application scenario uses only the input conveyer conv1, thus the usage of
the rotdisk control service is not necessary:
0. Statically move the rotary disk in conv1-conv4 position using the disk service.
1. Conv1 transports the work pieces to conv3.
2. Conv3 forwards the work pieces to conv4.
3. Conveyer conv4 moves the pieces through the lacquer machine.
4. The pusher sorts out erroneous pieces.
5. Acceptable items leave the system.
The service hierarchy used for the second scenario is depicted in Figure 5.
The application process of the second scenario uses seven control services. The subcomponent services of the rotary disk now are directly used to initially set up the right
direction of the disk and to control the conv3 at runtime. This change in the process outline
does not infer changes in the service implementations of the devices used.
Further scenarios were used to evaluate the applicability of multiple application
processes, each controlling a part of the overall process.
4. EVALUATION
The evaluation environment comprises three major components: the DPWS stack, the
Java Real-time VM and the simulation system.
The WS4D.org DPWS stack, developed by Dortmund University and Materna, is a Java
based implementation of the DPWS protocol stack and provides a service oriented
communication infrastructure.
It was developed with modularity and extensibility in mind and thus can be adapted
to varying application scenarios, ranging from small client-only implementations for mobile
phones to multimedia or file-sharing services for embedded settop boxes.
The Java Real-time System comprises technologies and concepts for correct
reasoning about the timing of Java real-time applications. It contains new types of real-time
threads, memory handling schemes preventing the garbage collector from influencing the
runtime behavior in a nondeterministic way), high precision timers with nanosecond
resolution and direct memory access for implementing device drivers purely in Java.
Nevertheless, the Java RTS depends on the real-time capabilities of the underlying operating
system.
For evaluation purposes we developed a testing environment, split into two blocks: a
simulation system and the sensor, actuator and control service implementations.
The time discrete simulation system is composed of four major components.
The simulation model component manages a grid model for locating devices,
sensors and work pieces in the system and a component model for preserving the state of the
simulated components.
The simulation control component periodically updates the model information.
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Figure 3. Example system
Figure 4. Scenario 1 service hierarchy
Changes in the internal state of sensors and actuators are sent to and received from the
distributed components via an UDP based communication protocol. It was especially
designed to consume few network bandwidth.
A graphical user interface is used to track and control the simulation.
The simulated system comprises sensor, actuator and
control service
implementations. The sensor and actuator implementations are connected to the simulation
system via the UDP based communication protocol (s.a.) to receive and publish state
information.
The simulations were run on an Athlon64 X2-3800 machine with two GB of memory
and an OpenSolaris installation as basis for the Java RTS.
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Figure 5. Scenario 2 service hierarchy
4.1. EXPERIMENTAL RESULTS
A series of experiments focused on the evaluation of the functional behavior of the
control system. Particular test sequences checked the feasibility and stability of the leasebased allocation. Atomic allocation and setup of service ensembles were as well tested as
atomic lease prolongation and occasional aborts followed by the searching and switching to
alternative ensembles.
In the course of additional experiments the service call roundtrip times (using simple
input and output parameters) were measured in order to check the current real-time limits of
Java VM and DPWS based control system implementations.
Table 1 presents the values obtained for local VM-internal (on the OpenSolaris host)
and for remote DPWS-based service calls (between the OpenSolaris and the PC host).
The configuration was able to support low to medium realtime requirements (e.g. cycle times
>50ms).
5. CONCLUSIONS
We have presented a service-oriented control architecture for automation systems. The
architecture forms a service hierarchy ranging from low-level sensor and actuator services,
over a number of control service levels up to application processes. Instead of statically
associating services for the different client operations, a flexible lease based binding
approach is used.
Table 1. Action call roundtrip times
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This approach follows the loosely coupled nature of components in service-oriented
architectures. The algorithm used for the flexible binding approach was tested in different
application scenarios.
The evaluation results regarding action call roundtrip time exhibit that the Java-based
service-oriented approach may not yet be a feasible solution for all applications. However,
the applicability can be extended by using e.g. hardwarebased message processing and realtime capable network infrastructures .
6. REFERENCES
[1] H. Smit, F. Jammes, ―Service-Oriented Paradigms in Industrial Automation‖, IEEE
Transactions on Industrial Informatics, Vol. 1, No. 1, pp. 62-70, 2005.
[2] C. Gray, D. Cheriton, ―Leases: an efficient fault-tolerant mechanism for distributed file
cache consistency‖, ACM SIGOPS Operating Systems Review, Vol. 23, Issue 5, pp. 202210, Dec. 1989.
[3] Universal Plug and Play (UPnP), http://www.upnp.org, 1999.
[4]
Devices
Profile
for
Web
Services
(DPWS),
http://schemas.xmlsoap.org/ws/2006/02/devprof/, 2006.
[5] Service Infrastructure for Real-time Embedded Networked Applications (SIRENA),
http://www.sirena-itea.org, 2006.
[6] Sun Microsystems, Jini, Network Technology, http://www.sun.com/software/jini, 1999.
[7] Kapsers, Küfner, ―Messen – Steuern – Regeln: Elemente der Automatisierungstechnik‖,
Vieweg Verlag, 6th Edition, p. 253, 2006. [5] Service Infrastructure for Real-time Embedded
Networked Applications (SIRENA), http://www.sirena-itea.org, 2006.
[8] WS4D.org Java Multi Edition DPWS Stack, http://www.ws4d.org, 2007.
[9]
Sun
Java
Real-time
System
2.0
(Java
RTS),
http://java.sun.com/javase/technologies/realtime, 2007.
[10] PROFINET, http://www.profibus.com/pn/, 2007.
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SERVICE ORIENTATION IN DISTRIBUTED AUTOMATION AND
CONTROL SERVICE
Prof.dr.ing.Cristiana VOICAN,University Politechnic of
Bucharest,[email protected]
Abstract: An experimental study shows the feasibility ofservice-oriented architectures for industrial automation
and control systems even with respect to lower, real-time dependent control functions. For that purpose, general
SOA-guidelines were refined in order to cover the distribution of control functions between services and the layout and management of devicebased sensor, actor and control services. Particular emphasis was placed on the
dynamic lease-based binding of services which on the one hand provides flexible and loose coupling of system
components but on the other hand has to ensure reliable communication and cooperation. The guidelines were
applied to the experimental implementation of a manufacturing cell control system using a real-time version of
the Java Runtime Environment.
The Device Profile for Web Services (DPWS) was used as basic infrastructure technology. Test and evaluation
were performed under distributed simulation of technical processes and devices.
Keywords: flexibility, equipment, software;
INTRODUCTION
Today, many modern business applications adhere to the paradigms of service
orientation and service oriented architectures in order to create loosely coupled, modular
software systems, easy to maintain and to extend. In the field of automation and control
systems, SOA-based flexibility is of even more interest, because it contributes to substantial
reductions of installation and setup costs .
These costs are of particular importance since manufacturing plants again and again
have to be adapted to new products resulting in changes of the technical equipment and the
process flows performed.
Additional reconfigurations are applied occasionally in the course of repair measures
in order to bypass defect equipment and to avoid expensive production downtimes.
Despite the desired flexibility, however, there is a needs for stable and reliable
operation phases since the efficiency of the production equipment usually depends on steady
operational conditions.
For a certain manufacturing operation usually an ensemble of suitable devices,
machines and transport equipment is necessary.
The members of the ensemble must initially be configured in harmony with each
other and thereafter be available for a certain minimal period of operation time, which may
only be aborted due to exceptional circumstances.
The members of the ensemble have to be allocated before configuration, some of them
because they can only be used exclusively, others may be sharable but have to allow for the
additional load.
In the service-oriented setting this means, that a client – which may be either a control
application or a compound service – must be able to search, find and allocate a suitable
ensemble of used services.
Since a used service may already have other obligations, it may not be disposable and
deny a current allocation request.
Then, one member of the planned ensemble fails, and the ensemble as a whole is currently not
useful.
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Therefore, the client shall be able to withdraw the other allocation requests and look
for alternative ensembles.
In order to fulfill these functional requirements of temporary and atomic ensemble
allocation we extended the approach of lease-based allocation by introducing an explicit
reservation phase in a way that reservation and allocation perform a two-phasem commitment.
Moreover we transposed the architecture of hierarchical control systems to the field of
service systems using the platform the Device Profile for Web Services (DPWS) as basic
infrastructure technology supporting the communication between devices via service
interfaces as well as the exploration and binding of services.
The application of the resulting architecture guidelines and the usage of the leasebased allocation were exemplified by means of a production cell scenario using a real-time
Java Runtime Environment.
In the sequel, we outline DPWS and its application to service-oriented industrial
applications.
SERVICE ORIENTED ARCHIECTURES
In SOA, interoperability of different platforms is established through the definition of
common communication protocol and message exchange standards.
But not only in enterprise domain software service-orientation is a feasible way of
creating flexible software systems, as through the growth of computing power of embedded
devices these paradigms are also applicable to embedded software solutions.
Universal Plug‘n‘Play (UpnP was the first specification of a service oriented
infrastructure to be used in embedded application scenarios, using SOAP and HTTP as a basic
communication layer and providing mechanisms for service discovery, action invocation and
event based communication schemes.
Its successor, the Devices Profile for Web Services (DPWS) , is completely based on
standardized Web service specifications and defines a profile (a subset) for the use of Web
service technology in the embedded domain.
DEVICES PROFILE FOR WEB SERVICES
The Devices Profile for Web Services defines a common subset of web service based
communication patterns for use in embedded devices.
The protocol stack utilizes standardized internet protocols, namely TCP/IP and UDP
(Single- and Multicast). For basic messaging HTTP and SOAP respectively SOAP-over- UDP
are employed.
On top Web service protocols are arranged that deal with service and device
description, discovery, eventing and security.
A DPWS device may host several services, which can be discovered and used by
DPWS clients. The DPWS protocol stack is depicted in Figure 1.
2.2. SOA in Industrial Automation
The emergence of powerful but less power consuming, affordable, and embedded
computing components facilitates the employment of SOA paradigms even in the world of
industrial automation
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Currently a lot of proprietary standards in device control and communication
protocols often prevent the vendors.
Thus upgrades or extensions of the manufacturing automation system tend to be
costly and time consuming .
The usage of SOA in industrial automation provides a common ground for
interoperability of all devices in a device network.
Moreover an integration of low-level devices and highlevel enterprise applications
(e.g. an ERP system) is possible.
In the European ITEA SIRENA project the applicability of DPWS in an industrial
automation scenario was demonstrated for the first time.
Figure 1. DPWS protocol stack

AUTOMATION AND CONTROL
An industrial control system commonly has a structure as depicted in Figure 2. This
architecture could be divided into three main layers: sensors and actors, control and
management.
The actual technical process is located at the bottom of the control hierarchy and
subsumes all technical lowlevel components involved in the production process like motors,
pushers or drilling machines.
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The process is monitored by sensors, collecting data from the involved resources
including e.g. temperature, rpm or the position of work pieces (indicated by a light-barrier
state change).
This information is send via a specialized communication infrastructure to the process
control level and is repeatedly evaluated by the control algorithm.
Based on the sensor information the control algorithm computes control signals which
are in turn send to the actuators connected to the technical process.
Moreover status information from the process control level is sent to the process management
level.
This may include forwarded sensor values, proinformation and fault messages.
At process management level a human operator monitors the overall process
behavior, adjusts particular parameters and sends configuration commands to the process
control system.
Besides the remote high-level controlling and monitoring of the technical process, in
some occasions (e.g. a severe fault that requires local intervention and repair) the operator
may be forced to directly intervene with the low-level hardware components via the attached
control pan.

SERVICE CONTROL ARCHITECTURE
The process control architecture shown in the last paragraph is the structural basis for
the service-oriented architecture presented in this paper.
The serviceorientation of the devices involved in the technical process and the
attached sensors suggests the use of service-orientation also on the control and management
levels.
The sensors and actuators export their functionality through defined interfaces which
can be used by higher level control services.
Control services may also be layered and arranged in a service hierarchy.
Figure 3 illustrates this architecture: the application process interacts with the
technical process using the supplied control services.
The control services themselves are acting both as a service consumer (client role) and
service provider (server role) and thus enable control service layering.
For example, a rotary disk consists of a rotation motor and a motor for moving the conveyer
belt on top of the disk.
Additionally the disk is supplied with sensors, detecting the location of the work piece
currently transported on the conveyer belt and a sensor to measure the position of the rotary
disk itself.
Both, the rotary part and the transportation part are each controlled by their own
control service.
For the control of the overall process of moving a work piece on the disk, stopping the
conveyer, turning the disk to its new position and finally transporting the work piece away
from the rotary table, an additional control service is provided that uses the control services of
the particular parts of the rotary disk. Therefore the control services themselves offer service
functionality to higher level control or management services.
However, the stacking of control services is constrained by the real-time requirements of the
process, as each new layer of control implies additional, time consuming
communication between the services
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.
Figure 2 Control system
Figure 3. Service hierarchy
CONCLUSIONS
The services (e.g. sensor or controller) offer different interfaces which can be
categorized using the follow three classes:
-
functional purpose
discovery and description
service binding
The functional interface offers the functionality of the service, e.g. a getVariable
method for sensor or a setVariable method for actuator services.
The functional service interface of control services offers high-level methods like
drillHole.
The control services comply with the notion of so called function building blocks (IEC
61499).
Each building block comprises input and output variables plus local status variables.
The functionality of a particular function block is defined by the algorithm that is used to
compute the outputs by using the inputs and the local variables.
The discovery interface contains the necessary methods for services to be able to
answer to search requests and to provide data concerning device type, location and binding
address.
Finally, the binding interface subsumes the features for lease based service binding
and reservation.
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REFERENCES
[1] H. Smit, F. Jammes, ―Service-Oriented Paradigms in Industrial Automation‖, IEEE
Transactions on Industrial Informatics, Vol. 1, No. 1, pp. 62-70, 2005.
[2] C. Gray, D. Cheriton, ―Leases: an efficient fault-tolerant mechanism for distributed file
cache consistency‖, ACM SIGOPS Operating Systems Review, Vol. 23, Issue 5, pp. 202210, Dec. 1989.
[3] Universal Plug and Play (UPnP), http://www.upnp.org, 1999.
[4]
Devices
Profile
for
Web
Services
(DPWS),
http://schemas.xmlsoap.org/ws/2006/02/devprof/, 2006.
[5] Service Infrastructure for Real-time Embedded Networked Applications (SIRENA),
http://www.sirena-itea.org, 2006.
[6] Sun Microsystems, Jini, Network Technology, http://www.sun.com/software/jini, 1999.
[7] Kapsers, Küfner, ―Messen – Steuern – Regeln: Elemente der Automatisierungstechnik‖,
Vieweg Verlag, 6th Edition, p. 253, 2006.
[8] WS4D.org Java Multi Edition DPWS Stack, http://www.ws4d.org, 2007.
[9]
Sun
Java
Real-time
System
2.0
(Java
RTS),
http://java.sun.com/javase/technologies/realtime, 2007.
[10] PROFINET, http://www.profibus.com/pn/, 2007.
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INDEX AUTHORS
Nr.
crt
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
29.
30.
31.
32.
33.
34.
35.
36.
37.
38.
39.
40.
41.
441
Name and Surname
AMZA Catalin Gh
AMZA Gheorghe
ANTONESCU Ovidiu
ANTONESCU Păun
APOSTOLESCU Zoia
BABIŞ Claudiu
BALDEA Monica
BĂRBĂCIORU Iuliana Carmen
BEAZIT Ali
BOKOR Corina
BORDOŞ Sorin
BOROIU Alexandru
BOROIU Andrei-Alexandru
BULAC Ion
BUNECI Mădălina Roxana
BURIAN Sorin
BURLAN Tudor
BUSA Eugen Dumitru
CAINICEANU Liliana
CĂLINOIU Maria
CĂPĂŢÎNĂ Camelia
CHINDA Dan Horia
CHIVU Oana Roxana
CIOFU Florin
CÎRȚÎNĂ Liviu Marius
DAIAN Gheorghe Iulian
DOBROTA Dan
DUMITRIU Mădălina
FRIEDMANN Martin
FULOP Daniela Dorina
FULOP Istvan
GAVRIS Ovidiu
GĂMĂNECI Gheorghe
GHEORGHIOSU Edward
GHICIOI Emilian
GHIMISI Stefan
GIRDU Constantin Cristinel
GRIGORE Jan-Cristian
GROZA Maria Dragomir
GUTSALENKO Yury
HITICAS Ioan
Pag
126
120, 126, 153, 229, 237, 406
112
112
229, 237
406
68, 303
336
329
191
276
343
343
5
350, 356
297
89, 94
243
89, 94
291
248, 253
259
133
137, 143, 191, 212, 314
147
375
120, 153
11
297
265
265
271
248, 253
276, 287
318
18
360
343, 363
229, 237
159, 164
23, 29
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42.
43.
44.
45.
46.
47.
48.
49.
50.
51.
52.
53.
54.
55.
56.
57.
58.
59.
60.
61.
62.
63.
64.
65.
66.
67.
68.
69.
70.
71.
72.
73.
74.
75.
76.
77.
78.
79.
80.
81.
82.
83.
84.
85.
442
HRISTOVA Teodora
IANĂŞI Cătălina
IANCU Cătălin
ILINCIOIU Dan
IONICI Cristina
IORGA Danila
IOVAN Stefan
IOVANOV Miodrag
ISARIE Ilie
JURCA Adrian
KOVACS Attila
LITRA Marcel
LUCA Liliana
LUPU Leonard
MAGYARI Mihai
MAZILU Traian
MIHON Liviu
MIHUT Nicoleta-Maria
MININ Ivan
MIRITOIU Cosmin
MIRIŢOIU Cosmin-Mihai
MIRONENKO Alexander
MITSI Sevasti
MOLDOVAN Lucian
MOROIANU Corneliu
NICA BADEA Delia
NIOATA Alin
NIŢOI Dan
PAISE Liana Sanda
PANDURU Dumitru
PARIS Adrian Stere
PASĂRE Minodora Maria
PATRU Emil
PĂRĂIAN Mihaela
PĂUN Florin Adrian
PECINGINĂ Irina Ramona
PICIOREA George
PLESEA Valeriu
POPA Roxana Gabriela
POPESCU Diana
POPESCU Gheorghe
POPESCU Iulian
PRISACARIU Ilie
RADU Constantin
370
282
170, 176
36, 42
183, 187
23, 29
375, 382
388
191
318
276, 287
382
49, 55
318
297
62
23, 29
392, 397
370
218
36, 42
164
49
297
72
201, 307
137, 314
406
229, 237
218
401, 406
197, 201, 307
218
318
318
324
29
203
291
126
77, 82
49, 55
133
133
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86.
87.
88.
89.
90.
91.
92.
93.
94.
95.
96.
97.
98.
99.
100.
101.
102.
103.
104.
105.
106.
107.
443
RĂDULESCU Constanța
RESIGA Emanuel
ROSU Catalin
RUS Daniela-Carmen
RUSU Tiberiu
SAMOILESCU Gheorghe
STANESCU Constantin
STANIMIR Alexandru
STĂNCIOIU Alin
TĂTARU Mircea Bogdan
TĂTARU Ion
TĂTARU Vladimir Dragoş
TOMESCU Cristian
TRETYAK Tatyana
UNGUREANU V.M.
URICANU Narcis
VĂTAVU Niculina
VIOREL Dan
VLAICU POPA Marius Eremia
VOICAN Cristiana
VULKOV Michail
147, 208
23
218
287
265
329
89, 94, 428
218
143, 212
411, 417
36, 42
411, 417
203
164
423
23, 29
318
265
203
428, 435
100, 106
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444
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INDEX KEYWORDS
A
articulaţie
aesthetic curves and surfaces
alumina
advanced gearing
airport
art
ANOVA
admittance
avulsion conductors
aluminium
analytic models
alloy
assessment risk
B
bac
blasting facility
biofilters
BIC-code
binding energy of metal
bioremediation
biofilm
C
cardan
connection
carbon nanomaterials (CNs)
clivage
composite coatings
cutting
charging
confined explosive charges
controller with a ring valve
censored tests
clearances.
continuous transport
Crimping
constant normal pitch
compression
crystal-growth
chain dimensions
chromating
cement concrete
conveyor belt
computing program
computational analysis of dynamical
combined transport
D
dynamic vertical load
design
drum mill‘s engine
dimension chain
dynamical system
E
ecuaţie
eigenmodes
eigenvectors
environmental
explosive sublimation
elaboration time
explosives for civil use
electric power drive
energy lines
Enterprise Services Architecture
equipment
excitation
eigenfrequency
electrical detonator
eco technologic
eutectic
elongation
electric detonators
exposure
equivalence relation
Euler-Lagrange algorithm
F
fretting
factors
frequency converter
flowing
fuzzy sets
freight containers
445
furnace
flameproof
flame resistance
fuzzy numbers
fuzzy random variables
flexibility
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G
Green‘s functions
grains surface
graphene
glass
graphological method
gear cutter
gases
groupoid
H
hardness
Hopfield neural networks
hardness
harmonized standard
health impact
high-speed diamond-spark grinding
hardening and tempering
hypothesis testing
I
internal combustion engine
internal combustion engine
implementation
industrial quality inspection
infrastructure
intermodal
interface
intake manifold
influence function
image segmentation
impact resistance
informational system
ILU-code
L
laser-sintering
linear elastic calculation
lambda
load sharing model
M
modal parameter
magnet
mining subsidence
multiparametric mappings of space
manganese steel
manufacturing centers
multi-criteria analysis
microorganisms
mechanical system
motion blocking
mechanism with multiple cams
mining geomechanics
management system
molded profiles
melting
maintenance
management
Malkin's model
movement blocking
matrix
N
normalization
neural network
numerical method
noise
non-linear systems
O
oil-water emulsion
optimization
operation engine
objective
P
peak revolutions
powertrain (engine) control unit
parameterization
powder
porosity
prealloyed
plasma
perception
probability
pressure decline
446
performances
parts
piezoelectric materials
protective atmosphere
powder iron
powder steel
productivity
polluted
potentially explosive atmosphere
production equipments
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R
roţi
random
reaction function
regeneration boiler
reliability modeling
road rehabilitation
relative
railway vehicle
response
rectified
risk assessment
reliability
rigid constraints
S
simulation CFD
stepping mechanism
Shaping
spring
standard deviation
sintered material
sintering
simulation
signalization
soils
static electricity
subordinate input parameters
statistical methods
seqences
service
software
software programs
short-pitch corrugated rail
simulation
speaker
synthesis techniques
sintered boron
sparks
smoke
safety
scientific research
single particle operators
Service Oriented Architecture
slide
subspace
structure
T
track irregularities
toy mechanisms
transducer
tenacity
transport
technologies
topology
transition
trammel mechanism
tolerance
TopSolid
triplex
truncated tests
U
ultrasonic motors
users interface
V
variable friction coefficient
vaporization
vehicles
vibrations
Vickers hardness tests
variable
W
wheelset
welding on health
welding fatigue experiments
447
welding
Weibull law
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The Journal includes papers presented at the 5th Symposium
Durability and Reliability of Mechanical Systems - SYMECH 2012,
organized by:
„Constantin Brancusi‖ University of Targu-Jiu, Engineering Faculty
Engineering and Management for Technological Systems Department
General Association of Romanian Engineers –Gorj Subsidiary
Research Center „Mechanical systems’ durability and reliability‖
SCIENTIFIC COMMITTEE
President:
Professor Stefan Ghimisi
"Constantin Brâncuşi" Univ. of Târgu-Jiu
Vice- president: Professor Liliana LUCA
"Constantin Brâncuşi" Univ. of Târgu-Jiu
Members:
Amza Gheorghe, Univ. ―Politehnica‖ of Bucharest
Cîrţînă Liviu Marius, "C-tin Brâncuşi" Univ. of Târgu-Jiu
Cofaru Nicolae, Univ. ―Lucian Blaga‖ of Sibiu
Cherciu Mirela, University of Craiova
Denes Călin, Univ. ―Lucian Blaga‖ of Sibiu
Dobrotă Dan, "C-tin Brâncuşi" University of Târgu-Jiu
Dobrescu Tiberiu, Univ. ―Politehnica‖ of Bucharest
Dumitru Nicolae, University of Craiova
Enăchescu Marius, University of California-Berkeley
Gutsalenko Yury, Kharkov Polytechnic Institute, Ukraine
Hristev Emil, Mining and Geology University of Sofia
Iancu Cătălin, "C-tin Brâncuşi" University of Târgu-Jiu
Mihăiţă Mihai, Vice- president Romanian Academy of
Technical Sciences
Mitsi Sevasti, University of Thessaloniki, Greece
Militaru Constantin, Univ. ―Politehnica‖ of Bucharest
Mitelea Ion, „Politehnica‖ University of Timişoara
Pandrea Nicolae, Univ.of Piteşti, corresponding member
of Romanian Academy of Technical Sciences
Pasare Minodora, "C-tin Brâncuşi" University of Târgu-Jiu
Petre Alexandru, „Transilvania‖ Univ. of Braşov
Popescu Iulian, Univ. of Craiova, corresponding member
of Romanian Academy of Technical Sciences
Popescu Gheorghe, "C-tin Brâncuşi" University of Târgu-Jiu
Radovanovici Miroslav, University of Niš, Serbia
Samoilescu Gheorghe, ― Mircea cel Bătrân‖ Naval Academy
Stanimir Alexandru, University of Craiova
Sucala Felicia, Tehnical University of Cluj Napoca
Tudor Andrei, Univ. ―Politehnica‖ of Bucharest
Vladut Gabriel Catalin, president Romanian Association
for Technology Transfer and Innovation
449
Fiabilitate si Durabilitate - Fiability & Durability Supplement no 1/ 2012
Editura “Academica Brâncuşi” , Târgu Jiu, ISSN 1844 – 640X
450
Fiabilitate si Durabilitate - Fiability & Durability Supplement no 1/ 2012
Editura “Academica Brâncuşi” , Târgu Jiu, ISSN 1844 – 640X

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