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THE JOURNAL OF THE INSTITUTION OF ENGINEERS, MALAYSIA
KDN PP5476/10/2012 (030203) | ISSN 0126-513X
Tel: 03-7968 4001/4002 Fax: 03-7957 7678 E-mail: [email protected] Homepage: htp://www.myiem.org.my
J
VOL. 76, NO. 1 | JULY 2015
L
IEM
OURNA
Vol. 76, No. 1, July 2015
KDN PP5476/10/2012 (030203) ISSN 0126-513X
MajliS Bagi SeSi 2015/2016 (ieM CounCil SeSSion 2015/2016)
YANG DIpERTUA / pRESIDENT
Y.Bhg. Dato’ Ir. Lim Chow Hock
TIMbALAN YANG DIpERTUA / DEpUTY pRESIDENT
Ir. Tan Yean Chin
naiB Yang DiperTua / ViCe preSiDenTS
Y.Bhg. Dato’ Ir. Dr Andy Seo Kian Haw, Ir. Lee Weng Onn, Ir. Gopal Narian Kuty, Ir. Prof. Dr
Ruslan bin Hassan, Ir. Lai Sze Ching, Ir. Lee Boon Chong, Ir. David Lai Kong Phooi
SeTiauSaha KehorMaT / honorarY SeCreTarY
Ir. Yam Teong Sian
bENDAHARI KEHORMAT / HONORARY TREASURER
Ir. Prof. Dr Jefrey Chiang Choong Luin
bEKAS YANG DIpERTUA TERAKHIR / IMMEDIATE pAST pRESIDENT
Ir. Choo Kok Beng
bEKAS YANG DIpERTUA / pAST pRESIDENTS
Y.Bhg. Academician Tan Sri Dato’ Ir. (Dr) Hj. Ahmad Zaidee bin Laidin, Y.Bhg. Dato’ Ir. Dr
Gue See Sew, Y.Bhg. Academician Dato’ Ir. Prof. Dr Chuah Hean Teik, Ir. Vincent Chen Kim
Kieong
WaKil aWaM / CiVil repreSenTaTiVe
Ir. Prof. Dr Mohd. Zamin bin Jumaat
WaKil MeKaniKal / MeChaniCal repreSenTaTiVe
Ir. Dr Kannan M. Munisamy
WaKil eleKTriK / eleCTriCal repreSenTaTiVe
Y.Bhg. Dato’ Ir. Ali Askar bin Sher Mohamad
WaKil STruKTur / STruCTural repreSenTaTiVe
Ir. Hooi Wing Chuen
WaKil KiMia / CheMiCal repreSenTaTiVe
Ir. Prof. Dr Thomas Choong Chean Yaw
WaKil lain-lain DiSplin / repreSenTaTiVe To oTher DiSCiplineS
Ir. S. Kumar a/l Subramaniam
WaKil MulTiMeDia Dan iCT / iCT anD MulTiMeDia repreSenTaTiVe
Engr. Abdul Fatah bin Mohd. Yaim, M.I.E.M.
ahli MajliS / CounCil MeMBerS
Ir. Dr Tan Chee Fai, Ir. Kok Hee Poh, Ir. Tiong Ngo Pu, Ir. Yau Chau Fong, Ir. Teh Piaw Ngi, Ir.
Kim Kek Seong, Ir. Chong Chin Meow, Ir. Chin Kuan Hwa, Ir. Assoc. Prof. Dr Vigna Kumaran
Ramachandaramurthy, Ir. Lee Cheng Pay, Ir. Ong Ching Loon, Ir. Gary Lim Eng Hwa, Y.Bhg.
Dato’ Ir. Noor Azmi bin Jaafar, Ir. Aminuddin bin Mohd Baki, Ir. Mohd Radzi bin Salleh, Ir.
Ong Sang Woh, Ir. Mohd Khir bin Muhammad, Ir. Assoc. Prof. Dr Norlida Bini Buniyamin,
Y. Bhg. Dato’ Ir. Hanapi bin Mohamad Noor, Ir. Dr Ahmad Anuar bin Othman, Ir. Ishak bin
Abdul Rahman, Ir. PE Chong, Ir. Ng Yong Kong, Ir. Tejinder Singh, Ir. Sreedaran a/l Raman,
Ir. Roger Wong Chin Weng
ahli MajliS jeMpuTan / inViTeD CounCil MeMBerS
Y. Bhg. Datuk Ir. Rosaline Ganendra, Y. Bhg. Dato’ Ir. Abdul Rashid bin Maidin
pengeruSi CaWangan / BranCh ChairMan
1. Pulau Pinang: Ir. Dr Mui Kai Yin
2. Selatan: Ir. Assoc. Prof. Hayai bini Abdullah
3. Perak: Ir. Lau Win Sang
4. Kedah-Perlis: Ir. Abdullab bin Othman
5. Negeri Sembilan: Ir. Shahrin Amri bin Jahari
6. Kelantan: Ir. Mohd Zaki bin Mat
7. Terengganu: Ir. Hj. Abdullah Zawawi bin Mohd. Nor
8. Melaka: Ir. Nur Fazil Noor Mohamed
9. Sarawak: Ir. Haidel Heli
10. Sabah: Ir. Tan Koh Yon
11. Miri: Ir. Steven Chin Hui Seng
12. Pahang: Y. Bhg. Dato’ Ir. Hj. Abdul Jalil bin Hj. Mohamed
CONTENTS
1
Exploring the Viability of Dams is Key to Malaysian
Water Resources Development of the Future
by Dato’ Ir. Syed Muhammad Shahabudin
24 Control of Bifurcation Behaviour of the Buck Converter Via A
Resonant Parametric Perturbation Circuit
by Ir. Dr Ng Kok Chiang, Dr Michelle Tan Tien Tien, Dr Nadia Tan
Mei Lin
32 Characteristics of Optical Silicone Tactile Sensor
by Nurul Fathiah Mohamed Rosli, Muhammad Azmi Ayub and
Roseleena Jaafar
38 Effect of Polishing Grits, Temperatures and Selected Activators
on Electroless-nickel Deposition on Cast Aluminium
Substrates
by Ajibola Olawale Olarewaju, Oloruntoba Daniel Toyin, and
Adewuyi Benjamin Omotayo.
47 Effect of Grinding on Workability and Strength of Penang Rice
Husk Ash Blended Concrete Grade 30
by Rahizuwan Hamid, Norisham Ibrahim
52 Guideline for Authors
AHLI JAWATANKUASA INFORMASI DAN pENERbITAN /
STanDing CoMMiTTee on inForMaTion anD puBliCaTionS 2015/2016
Pengerusi/Chairman: Ir. Prof. Dr Ruslan Hassan
Naib Pengerusi/Vice Chairman: Ir. Mohd. Khir Muhammad
Seiausaha/Secretary: Ir. Lau Tai Onn
Ketua Pengarang/Chief Editor: Ir. Prof. Dr Ruslan Hassan
Pengarang Bulein/Bullein Editor: Ir. Mohd. Khir Muhammad
Pengarang Prinsipal Jurnal/Principal Journal Editor: Ir. Prof. Dr Dominic Foo Chwan Yee
Pengerusi Perpustakaan/Library Chairman: Ir. C.M.M. Aboobucker
Ahli-Ahli/Commitee Members: Y.Bhg. Datuk Ir. Prof. Dr Ow Chee Sheng, Engr. Abdul
Fatah bin Mohamed Yaim, M.I.E.M., Ir. Dr Kannan a/l M. Munisamy, Ir. Chin Mee Poon,
Ir. Yee Thien Seng, Ir. Ong Guan Hock, Ir. Dr Wang Hong Kok, Ir. Dr Oh Seong Por,
Ir. Dr Aminuddin Mohd Baki, Ir. Tejinder Singh
LEMbAGA pENGARANG/EDITORIAL bOARD 2015/2016
Ketua Pengarang/Chief Editor: Ir. Prof. Dr Ruslan Hassan
Pengarang Bulein/Bullein Editor: Ir. Mohd. Khir Muhammad
Pengarang Jurnal/Journal Editor: Ir. Prof. Dr Dominic Foo Chwan Yee
Ahli-ahli/Commitee Members: Ir. Ong Guan Hock, Ir. Lau Tai Onn, Ir. Yee Thien Seng,
Ir. Dr Wang Hong Kok
Secretariats: Janet Lim, May Lee
THE INSTITUTION OF ENGINEERS, MALAYSIA
Bangunan Ingenieur, Lots 60 & 62, Jalan 52/4,
P.O.Box 223 (Jalan Sultan),
46720 Petaling Jaya, Selangor Darul Ehsan.
Tel: 03-7968 4001/4002
Fax: 03-7957 7678
E-mail: [email protected] Homepage: htp://www.myiem.org.my
THE TWENTY THIRD
PROFESSOR CHIN FUNG KEE MEMORIAL LECTURE
Presented at Auditorium Tan Sri Prof. Chin Fung Kee,Wisma IEM, Jalan Selangor, 46200 Petaling Jaya,
Selangor, Malaysia on 7th December 2013
Dato’ Ir. Syed Muhammad Shahabudin
DSDK, PJK, PEng, MIEM, FICE, Chartered
Water and Environmental Manager, UK
Non-executive Chairman, SMHB Sdn. Bhd.
Dato’ Ir. Syed Muhammad Shahabudin has been in the water
engineering ield for close to 50 years most of which in private
practice as a consulting engineer. He graduated as an engineer
from Plymouth College of Technology, United Kingdom
and is a Professional Engineer Malaysia, a Member of The
Institution of Engineers Malaysia, a Fellow of the Institution of
Civil Engineers, United Kingdom and a Chartered Water and
Environmental Manager, United Kingdom.
After serving the Government of Malaysia for 12 years,
the last appointment being the Chief Executive Engineer of
the newly-formed Penang Water Authority (1973-74) on
secondment from the Public Works Department, he became as
partner in the consulting engineering irm of Binnie dan Rakan
(BDR) Malaysia, a member of the international group of Binnie
and Partners, United Kingdom with practices in South-East
Asia and Hongkong specializing in water engineering. BDR
was restructured in 1980 as Syed Muhammad, Hooi dan Binnie
Sdn Bhd and Dato’ Ir. Syed Muhammad Shahabudin became
the Chairman and Managing Director. The irm was completely
taken over by Malaysians in 1995 and SMHB Sdn Bhd was
formed. He assumed the duty as Executive Chairman.
Journal – The Institution of Engineers, Malaysia (Vol. 76, No. 1, July 2015)
Dato’ Ir. Syed Muhammad Shahabudin has made many
contributions towards the ield of engineering particularly to
the Association of Consulting Engineers Malaysia as President
(1985 – 1987), the Malaysian Water Association as President
(1994 – 2007).
As President of Malaysian Water Association, he led a
team in initiating the transformation of water services industry,
taking the matter up in 2004 to the Minister who obtained
Government’s approval to eventually form National Water
Services Commission (SPAN) three years later.
As Chairman of Malaysian Water Partnership (2007 –
2011), he was committed to the implementation of Integrated
Water Resources Management (IWRM) and strongly believes
that this is the best approach which can promote sustainability of
water resources management in Malaysia.
He has been a board member of Selangor Water Management
Board (LUAS) since its formation in 2000 and is currently a
member of the National Water Services Commission (SPAN)
since its formation in 2007. He is a Fellow of the Academy of
Sciences Malaysia, established under the Act of Parliament to
pursue, encourage and enhance excellence in the ield of science,
engineering and technology. He is currently Chairman of Task
Force on Water Demand Management.
1
Exploring The Viability of Dams is Key to Malaysian Water
Resources Development of the Future
(Date received: 30/10/14/Date accepted: 11/8/2015)
Dato’ Ir. Syed Muhammad Shahabudin
DSDK, PJK, PEng, MIEM, FICE, Chartered Water and Environmental Manager, UK,
Non-executive Chairman, SMHB Sdn. Bhd.
E-mail: [email protected]
ABSTRACT
It is said that civilization began and prospered when humans could control water; and that same civilization declined and
vanished when that control is lost. Dams and other river low barriers were built to harness and control water in the early days
of civilisation in order to secure the beneits for human basic needs and comfort. Centuries later, more dams were built to cater
for increasing population, especially in arid and semi-arid areas. But it is really in the past two centuries that many large-sized
dams have been built to satisfy a wider range of development demands – hydropower, treated water supply, irrigation, lood
control and environmental needs.
Towards the second half of the last century, society came to realise that dams can cause signiicant negative social and
environmental impacts that could outweigh the original economic beneits. Opponents of dams protest vehemently world-wide
against the development of more dams whilst proponents are convinced that they are a necessary feature to support growth and
prosperity. It is these contradicting beliefs in mind that the public must be engaged to facilitate a better understanding of the
views of both the proponents and the opponents of dam development before deciding on a long-term strategy. In the meantime,
more effort may have to be made for water and energy conservation strategies and to realize the potential applications of low
impact and non-structural solutions that complement existing dams and defer new dam development to as far into the future
as possible.
This paper aims to provoke a critical debate amongst engineers and the public to look at the longer term future of dams in water
resources development that could possibly reduce the fundamental demand for services that dam provides. In other words, to
try and answer the question “Why should a country rich in water, as Malaysia is, need to construct dams and even plan for
more?”
1.0 INTRODUCTION
It has often been argued by critics to large dams construction
in water resources development that economic and social
development can also be achieved without building dams. This
is theoretically possible but not easily implementable. More time
is needed for studies, research and assessment on alternatives
or other options, for example, in water reuse, recycling, water
footprint of conventional and renewable energy resources and
optimizing the overall use of water by fully utilizing water
demand management concept which calls for water conservation
in reduction of usage and pollution. Furthermore, unlike
advanced and industrialized countries where economically
exploitable water resources are nearly fully developed, in many
of the developing countries, demand for water is tremendous
and extensive undeveloped exploitable water resources are still
available for use. This is particularly so in energy production
utilizing hydro-electric dams and multipurpose dams. Malaysia
belongs to this category as a fast developing nation.
The challenge for the future will be the utilization of
dams in conjunction with climate, environment and land use
for the prudent management of water resources as part of the
nation’s social and economic development goals. This calls
for opportunities to fully utilise the most effective approach to
ensure the most sustainable outcome is achieved in cases where
there is not much choice but to build dams.
2
2.0 ENGINEERING LARGE DAMS IN
MALAYSIA
General
The engineering of dams is among the earliest structures built
by mankind. Since early civilization, dams have provided the
necessary quantities of water to sustain the population in semiarid and arid regions with a huge seasonal variability of rainfall,
with too little precipitation and too high evapotranspiration.
In such cases, there was no other choice but to build dams and
make water available for human needs and comfort especially
to cultures highly dependent on irrigation for security of food
supply.
For regions which experience signiicant precipitation,
the sustainability of life is hardly threatened by the imbalance
between demands and available supplies of water, food and
energy. Malaysia is among the countries blessed with good water
resources. Apart from the Bukit Merah Project, the provision of
large dams is, therefore, deemed unnecessary until much later in
time during the late 1920s and early 1930s.
International Commission on Large Dams (ICOLD) deines
Large Dam as having at least heights of 15m or 5-15m with at
least 3 million m3 (MCM) storage volume.
ExPLORING THE VIABILITY OF DAMS IS KEY TO MALAYSIAN WATER RESOURCES
DEVELOPMENT OF THE FUTURE
Table 2.1
Year of
Commission
Capacity
Ownership
Purpose
Bukit Merah
Project, Perak
1906
Augmented supply for
Irrigation (24,000 ha)
Perak Government
(Federated MalayStates)
Irrigation water supply
Chenderoh
Hydroelectric
1930
27 MW
Perak River Hydroelectric
Company
Supply to tin mines and other areas
Gunong Pulai II and
Pontian, Johor
1932
12 mgd
Straits Settlement
Government, Singapore
Water supply to Singapore
Project
The Early Dams
The earliest large dams in the country were constructed for three
different purposes, namely for irrigation needs of agriculture,
for hydroelectric generation and potable water supply (export to
Singapore) as seen on Table 2.1 above.
largest in Southeast Asia until after the Second World War (TNB
Publication 1993) as shown in Figure 2.1. The aim was to make
electricity available to the State of Perak for all purposes. But
the tin mining industry, especially after the advent of massive
dredging operations, was the driving economic force behind the
demand of electric power. The dam structure is a hollow buttress
type concrete dam.
The third is a combination of large dams at Gunung Pulai II
and Pontian in Johor, built by the Straits Settlment Government
for Water Supply to Singapore as shown in Figure 2.2. Singapore
was then part of the British administration in this region. The
View of Bukit Merah Dam, Perak
The irst large dam to be constructed in 1906 was a
homogeneous earth-ill dam at Bukit Merah, Perak built
primarily for irrigation purposes but later extended for other
uses like potable water supply, recreational use, ishing and
lood mitigation. In fact Perak was the irst state in the Federated
Malay States to be involved in the rehabilitation of existing
irrigation areas in Kerian in 1899. The interest in irrigation was
towards increasing the food supply levels in the state (History
of Irrigation in Malaysia: MOA). The dam reduced the risk of
crop failures for the only one cropping season practiced at the
time. The scheme was completed at a cost of 2,600,000 Straits
Dollars. The dam heights was raised twice the irst in 1965 and
again in 1984 and currently serves 24,000 hectares of the Kerian
Irrigation Scheme and double cropped every year. A view of the
dam is seen on the photograph.
The dam is now one of the major components of the Kerian
Irrigation Scheme, one of the 12 Granaries in Malaysia.
The Second large dam was built by the private company
as the irst hydro-electric project in the country: a 27 MW
Chenderoh Hydro-electric Power Station, across the Sg. Perak,
which was inaugurated in 1930, making it one of the largest
hydro developments in the British Empire at that time and the
Journal – The Institution of Engineers, Malaysia (Vol. 75,
76, No. 2,
1, Dec
July 2014)
2015)
Figure 2.1
Figure 2.1
3
DATO’ IR. SYED MUHAMMAD SHAHABUDIN
require stable supply of water throughout the year. In addition,
infrastructure systems were left much to be desired as the result
of negligence during the war. The large rain-fed irrigation areas
in Kedah, Perak and Kelantan were often at the mercy of poor
crop production during dry periods and severe looding.
View of Pulai II Dam, Johor
scheme took six years to be completed and was commissioned
in 1932 under dificult working conditions “on sites in tropical
jungle with serious outbreaks of malaria where work on one
dam had to be stopped to deal with the outbreak”. (Binnie Short
History, 1990). The job was completed by direct labour with
resident site staff buying all plants and materials and hiring
labour to get work done, using money provided by the client.
The main dam, Gunung Pulai II, is a masonry gravity dam, 37m
high as seen on the photograph and with a 31m high earth-ill
dam at nearby Pontian. The Gunong Pulai II masonry dam is
understood to be the only dam of its type built in Malaysia. The
job was inished at a cost of £2.6 million, a princely sum in those
days.
After the construction of these three earliest large dams,
there was about a 30 year gap before more dams were considered
for construction in the latter part of 1950s and after Merdeka.
In the meantime, in most parts of the country, there was still
abundant supply of water for abstraction and use.
The Post Second World War Period
The most signiicant period of dam construction took place
worldwide after the Second World War. Elsewhere in the
developed and industrialized countries, postwar reconstruction
and economic development was accompanied by phenomenal
construction of infrastructure systems between 1950-1980 when
7,600 large dams were commissioned in the 1970s (ICOLD:
2006).
For about the same period more large dams were planned
to meet shortages in water supply as some parts of the country
were not able to balance demand with supply of water for
potable supply and agricultural needs. This was particularly
so in urban centres like Kuala Lumpur and George Town with
marked increase in population after the war years. The pre-war
water supply from the upper reaches of Sg. Ampang at Ampang
Intake and Impounding (5 mgd) and Kuala Sleh (10 mgd) for
Kuala Lumpur municipal limits, could no longer meet the
increased demand of Kuala Lumpur and new extended areas.
Similarly George Town’s main sources of supply at the waterfall
(4 mgd), Guillemard (12 mgd) and Air Itam old plant (4 mgd)
could no longer satisfy the increased demand of the population.
Increased paddy cultivation to meet more food demand would
Figure 2.2: Gunung Pulai Scheme, Johor
However, with the formation of the Federation of Malaya
in February 1948, when all states of the peninsula were united
for the irst time under a Federal System of Government,
opportunities were created for reconstruction and development
of infrastructures for the whole country. Prior to this, there was a
Federal system in four states forming the Federated Malay States
(Selangor, Perak, Pahang and Negeri Sembilan), and the three
British Straits Settlements ((Singapore, Penang and Melaka).
The ive remaining states (Johor, Kedah, Perlis, Kelantan and
Terengganu) were self-governing under British protection. The
most remarkable advantage is the ability to reconstruct, plan and
improve infrastructure system in a concerted and most effective
way by all the states with close coordination by the Federal
Government.
Meanwhile, in 1949, one of the most important events in the
history of Malaysia’s power supply (TNB Publication 1993) took
place when public supply of electricity in the country became
the vested interest of the newly formed Central Electricity Board
(CEB).
With stability, after the war and uniication of states in
Malaya, came economic development and physical achievements
especially in the urban centres. The eventual achievement of
Independence in August 1957, economic development was
further extended to cover the whole country notably the rural
areas.
The First Dams After The Second World War
During the late 1940s until early 1960s, the following three large
dams were built as indicated in Table 2.2.
The Labong Dam (Irrigation)
The need for irrigation facilities (including dams even for
a single cropping system before the 1960s), is because of the
variability of rainfall within a year, between years and also
within the rainy and the dry seasons in a year. Dams provide the
2
YTL does not condone exploitation of labour, nor does the company allow for labour practices that jeopardise the health and safety of its employees. In the 1980s, it
acted within the purview of existing Malaysian Labour Laws that permitted 24-hour construction work. Thus, gaining strategic upper-hand over Japanese construction
irms that were not permitted to do the same.
4
Table 2.2
Year of
Commission
Capacity
Ownership
Purpose
Labong Dam
1949
Augmented supply for
Irrigation (1,184 ha)
Government of Johor
Irrigation water supply
Klang Gates Dam
1959
30 mgd
Government of Selangor
Water supply to KL and suburbs
Air Itam Dam
1963
City Council of George Town
Water supply to George Town
Project
6 mgd
stability of irrigation water supply and thereby reduce the risk of
crop failures, improve the chances of success for the only one
cropping season then and for double cropping now. With dams,
production became more consistent and therefore stable incomes
for farmers as well. The Labong Dam for the Endau Rompin
irrigation scheme, as shown in Figure 2.3, was commissioned in
1949 for single cropping system.
This dam is an earth-ill embankment dam and the scheme
has recently been added to be another one of the Granary Areas
for the country. With the re-activation, the whole scheme will
be for double cropping. The reservoir also supplies 0.5 mgd for
water supply needs.
the Ahning Dam, a rock-ill with concrete faced dam type, height
74 m, length 270 m, storage 275 MCM. The total annual release
from these dams is 1,600 MCM.
Plans are already underway to augment irrigation supply
to the southern region of this MADA Granary from the Beris
Dam (concrete faced rock-ill type, 40 m high, 155 m long, 122.4
MCM storage capacity). The dams also supply water for water
supply needs in Kedah, Penang and Perlis.
The Cameron Highlands hydroelectric dams
The year 1963 marked the CEB successful completion of its
irst major hydroelectric scheme in the Cameron Highlands.
The Klang Gates and Air Itam Dams (Water Supply)
The shortage of treated water supply became increasingly
apparent with the expansion of Kuala Lumpur and its suburbs
particularly the newly created Petaling Jaya in the 1950s
which called for urgent attention and the irst large dam in the
country for water supply (if supply from Gunong Pulai II is
discounted as water export) was commissioned in 1959 with the
completion of the Klang Gates arch gravity concrete dam (this
dam was eventually raised in 1979 to accommodate as a dual
purpose dam for lood mitigation). In the north, George Town,
Penang similarly needed to solve their water supply shortages.
The second large dam for water supply in the country, an earthill dam, was built by the City Council of George Town and
commissioned in 1963.
Major Post War Schemes Involving Dams
Pedu and Muda dams (Irrigation)
This is perhaps the largest “Twin” Dams in Malaysia.
Constructed in 1966, it supplies 30% of the total irrigation
requirement to the largest irrigation scheme in Malaysia, the
Muda Irrigation Scheme (also known as the MADA: Muda
Agricultural Development Authority) Granary, totalling 96,558
ha. Interestingly, this scheme is not within the Muda River
Basin. The Muda River water is impounded by the Muda Dam
and transferred into the Pedu Dam in the Pedu River Basin
via the Saiong Tunnel (4.42 m diameter, 6.8 km length) and
subsequently released to irrigate the paddy ields. This MADA
Granary is now the premier rice bowl of Malaysia consistently
producing 40% of the total National output with yields of more
than 6 tons/ha per season.
The Muda Dam is concrete ambursen buttress type with
overlow spillway. Its main dam is 37m height and 250m length.
Its storage capacity is 160 MCM. The Pedu Dam is of rockill
with upstream asphaltic concrete membrane type with its main
dam at 61 m height and 220 m length with a reservoir storage
capacity of 1,073 MCM. The irrigation supply is augmented by
Figure 2.3: Labong Scheme, Johor
(Sources: http://www.mada.gov.my, http://www.water.gov.my/ : 22 October
2013-9.30am)
Figure 2.4
5
The scheme started in 1959 and about half the £15 million cost
represented the civil engineering works (Binnie short history
1990). “Much of the initial survey work in 1955 had to take
place in virgin jungle, but in addition there were still a number
of guerilla camps in the area”. The power house was constructed
260m underground, the machine hall being 24m high by 15m
wide. Some 26km of tunnels were driven, the last section feeding
the turbines having driven at 45º to the horizontal. The 40m high
dam to pond the power water was a buttress design, Sultan Abu
Bakar (Ringlet) dam, fully closed in on the downstream face to
permit overspill to occur over the whole crest of the dam.
The construction of the similar Batang Padang hydroelectric
scheme downstream followed immediately and involved another
20 km tunnel, a 46m high earth dam and another underground
power station. Figure 2.5 indicates the Location Plan. The push
towards nationwide power supply was becoming a reality and
CEB was renamed National Electricity Board (NEB) in June
1965.
The 5-Year Development Plans
Systematic planning for economic development of the country
started with two 5-year Malayan Development Plans (1960–
1970) and followed by a series of 5-year Malaysian Development
Plans (1970–2015). The country is currently undergoing
implementation of 10th Malaysia Plan.
Table 2.3 indicates large dams built for various purposes
numbering 69 altogether by the end of 2000s. The locations
are shown on Figures 2.6 and 2.7. Over a period of 40 years
of economic diversiication from an agriculture based to
industrialization between 1960 and the end of 1990s, 45 large
dams were constructed in Malaysia; or at an average of more
than one dam constructed every year. Of these, 20 were in the
1980s; an average of about 2 dams per year over the decade.
Most of those dams were for water supply (43 dams), relecting
the need for timely water resources development to satisfy the
growing demands of the population and industry over those 40
years. The largest dam for Malaysian water supply is the Sg.
Selangor dam (235 MCM) as seen in the photograph. The dam
development momentum continued into the new millennium.
Between the year 2000 and 2013, 18 more new dams were
added or at an average of more than 1 dam per year, the largest
being the Bakun Hydroelectric Scheme, Sarawak (44,000 MCM
and with capacity 2400 MW) as seen in the photograph. Presently
(2013), six new large dams are under construction. These are:
•
Kelau, Pahang (water supply)
•
Ulu Jelai, Pahang (Hydroelectric)
•
Puah and Tembat, Terengganu (Hydroelectric)
•
Murum, Sarawak (Hydroelectric)
•
Paya Peda, Terengganu (Irrigation)
More dams are planned for the future. Based on the Review
National Water Resources Study in 2012 and other proposals
to date, another 73 dams are expected to be constructed in the
future.
Since 1960, not only were new dams constructed but there
were also existing dams re-developed to increase their capacities
by raising their dam heights. These are the Bukit Merah Dam
(1965 and 1984), the Klang Gates Dam (1979), Durian Tunggal
Dam (1992), Lebam Dam (1992) and Sg. Tinggi (2003). Works
View of Sg. Selangor Dam
Figure 2.5
6
to raise the TimahTasoh Dam height are currently on going and
plans to raise the Mengkuang Dam height are already irmed.
Unlike some dams in other countries (e.g. Mangla Dam in Pakistan
and Hinze Dam in Australia) that were planned and constructed
to be raised in the future, none of the existing dams in Malaysia
are known to have been planned, designed and constructed to
account for such long-term phased-development. However there
View of Bakun Hydroelectric Dam
are already serious considerations to review the existing dams
for possible dam height raise either to meet increasing needs or
as an adaptation strategy to absorb the projected extreme lood
lows due to climate change impacts.
Most of the dams in Malaysia are earth-ill dams. The
majority of sites are in mountainous country and foundations are
relatively uncomplicated. Alluvium depths are rather shallow
(10-15m) or absent. The weathered rocks in place have adequate
strength and stiffness. So they rarely control the embankment
slope angles. The residual soil and weathered rocks of Malaysia
makes an ideal ill material. The strength of the soil, the ease
with which it can be compacted and its fairly rapid rate of
consolidation to provide an economical cross-section for a
central core embankment dams.
The irst Roller Compacted Concrete (RCC) dam in Malaysia
was completed in 2006 as the Sg. Kinta dam at Ulu Kinta, Perak.
Dams were previously built by different government agencies
like the Public Works Department and various Water Authorities
Figure 2.6
7
8
Table 2.3: Major Dam Development in Malaysia
No.
Purpose
(Primary /
Secondary)
Before 1950s
Water Supply
Gunung
Pulai
Scheme
1. Pulai II
Dams
2. Pontian
Kechil
Dam
B
Hydropower
Chenderoh
Dam,
Perak
C
Irrigation
Bukit
Merah
Dam,
Perak1
Labong
Dam,
Johor
D
Flood
Mitigation
E
Environmental
F
Recreation
1960s
Air Hitam Dam,
Penang
Damansara Dam,
Selangor
Klang
Gates
Dam2
3
1970s
1
1
Lebam Dam,
Johor
Durian Tunggal
Dam, Melaka
Langat Dam,
Selangor
2
Cameron Highland
Scheme
Sultan Abu Bakar
(Ringlet Falls)
Dam, Pahang
Batang Padang
Scheme
Jor and Mahang,
Perak
1980s
3
Temenggor Dam,
Perak5
3
Mahang Agricultural
Development
Authority Scheme
Pedu and Muda Dams
2000s
Sg. Buloh (Tinggi)
Dam, Johor
Air Kuning
(Taiping) Dam,
Perak
Pedas Dam, N.S.
Juaseh Dam, N.S.
Upper Muar Dam,
N.S.
Gemencheh Dam,
N.S.
Kelinchi Dam, N.S.
Barbagon Dam,
Sabah
11
9
Sg. Selangor Dam,
Selangor
Chereh Dam, Kuantan
Betotan Dam,
Sandakan
Milau Dam, Kudat,
Sabah
Gerugu Dam, Sarikei,
Sarawak
Labu Dam, Selangor
Teluk Bahang Dam,
Penang
Telibu Dam, Sabah
Kerteh (KIPC),
Terengganu1
2010-2013
11
Anak Endau Dam,
Pahang1
Pontian Dam, Pahang1
1
43
2
12
Beris Dam
Timah Tasoh Dam,
Perlis3
1
3
Sg. Batu Dam, Selangor4
Sembong Dam, Johor1
Machap Dam, Johor3
3
Bakun
Dam,
Sarawak
Murum,
Sarawak
4
1
Total
Kinta,
Perak
Terian,
N.S.
Batu
Hampar,
N.S.
Pergau Dam,
Kelantan5
Kenyir Dam, Terengganu5
Batang Air, Sarawak
Bersia Dam, Perak
Kenering Dam, Perak
Bukit Kwong
Dam, Kelantan
2
Semenyih Dam, Selangor
Terip Dam, Negeri
Sembilan1
Malut Dam, Kedah
Ahning Dam, Kedah1
Mengkuang Dam, Penang
Layang Upper Dam, Johor
Layang Lower Dam,
Johor
Timbangan, Semporna,
Sabah
Sika, Bintulu, Sarawak
Bukit Kuda, Labuan
Paka (Bukit Bauk),
Terengganu
1990s
1
10
Bekok Dam, Johor4
2
1
3
Silt Retention Repas
Baru Dam, Pahang1
1
Putrajaya Dam,
Wilayah Persekutuan
6
1
8
5
20
12
1
1
13
5
69
A
1950s
(Water Supply). Department of Drainage and Irrigation
(Irrigation and Flood Control), National Electricity Board for
Peninsular Malaysia, Sarawak Electricity Supply Company
and the Sabah Electric Board Sdn Bhd. Since 2004, most of
the construction of water supply dams has been taken over by
agencies under the State Governments and Ministry of Energy,
Green Technologi and Water (KeTTHA), and irrigation dams by
agencies under the state government and Ministry of Agriculture
& Agro Based Industry (MOA). The states of Sabah and Sarawak
are directly responsible for construction of dams undertaken by
their agencies.
Catchment Control
A major problem facing reservoir operation in Malaysia is the
potential for intense erosion of the catchment. The majority of
the reservoirs have steep jungle-covered catchments. Under
conditions of intense tropical rainstorms even virgin jungle
catchments will produce serious soil erosion, as commented by
WJ Carlyle, a dam expert from United Kingdom, conversant
with dam implementation in Malaysia. According to him, “it is
not uncommon for 75% of the annual sediment yield to move in
a single storm even in normal conditions.”
In his expert view, the Sultan Abu Bakar (Ringlet Falls)
reservoir in the Cameron Highlands “presents a good example
of where the catchment area has been progressively denuded to
grow tea and vegetables and in 20 years of operation, the reservoir
has been virtually illed with sediment. An interesting secondary
problem of catchment management at Ringlet Falls Reservoir
is the development that has encroached into the corridor of the
river valley downstream. This used to be a “jungle” river when
the scheme was built, but has now been cleared for intensive
vegetable and lower cultivation. The concrete dam has loatoperated crest radial gates which open in response to rising
reservoir levels. It is now unsafe to operate these gates because
of the risk of life loss downstream.”
The recent tragedy which occurred on 23rd October, 2013
involving the loss of 3 lives, downstream of Sultan Abu Bakar
dam (as seen in the photograph) as a result of releases of large
volumes of water from the dam, emphasized on the need to
keep river reserves and corridors downstream free of human
settlements and low obstructions. This problem of catchment
management was previously raised by W.J. Carlyle in his
inspection report.
Catchment control needs an integrated approach by all parties
concerned at state level to maintain the designed life expectancy
of any dam as well as to minimize the risks associated with dam
structural integrity and dam operations particularly during large
volume releases of water during excessive stormwater lows.
Problems
In his review of dams built before 1990s, WJ Carlyle was not
aware of a failure of any Malaysian large dam over the 60
years of dam history. He is aware of only three incidents of any
signiicance:
(i) Serious leakage of an asphalt deck rockill dam. Leakage
was much reduced by underwater placement of clay blanket
layer
(ii) Failure of the spillway section of a low irrigation dam due to
piping and erosion of the concrete toe, which was rebuilt.
(iii) Slam failure of a 1800 butterly guard valve upstream of
a fully opened 1400 regulator valve on a 2200 outlet pipe
causing failure of pipe joints and some looding. On the
same dam but unrelated to the irst incident the accidental
looding of the outlet culvert (old diversion tunnel) causing
loatation of the empty twin 2200 pipes 500 m long, resulting
in damage to pipe addles and support straps -now repaired.
According to him, this is a good record and a credit to the dam
owners and builders. These are large dams designed by qualiied
engineers.
However, there are many small dams mainly in estates and
for storage of tailings that are constructed without proper design.
A famous tailing dam failure is Ampang Pechah in Kuala Kubu
Baru with a loss of many lives. Recently, another tailing dam
failed in Gambang, Pahang.
Photo credit: STAR publications (M) Bhd.
View of illegal farms within the Sg. Bertam reserve
Dam Safety
Malaysia has no central authority for enforcement of dam safety,
nor any governing legislation. Each dam owner is responsible
to carry out the inspection on the maintenance and safety of
his dam. State authorities are owners of dams for water supply
purposes, lood control and agricultural dams. The Ministry of
Agriculture and Agro-based Industry is jointly responsible with
state authorities for management of major agricultural dams.
The other owners are the electrical power authorities which own
and operate the hydroelectric dams in the Peninsula, Sabah and
Sarawak. Of recent times, design and construction of dams for
water supply purposes has been known to be privatized.
Although, there is no doubt that there is an appropriate
awareness of dam safety needs in Malaysia, the time has come
for need to have governing legislations to cater for Dam Safety.
This is also covered in Section 3 under “Effective Governance of
Water Resources Management”
A “Guideline for Operations, Maintenances and
Surveillance of Dam”, dated October 1989, was prepared by
an Inter-Departmental Committee on Dam Safety in Malaysia.
The members of the Committee were Public Works Department,
Tenaga Nasional Bhd, Department of Irrigation and Drainage,
Sabah Electricity Board, Sarawak Electric Supply Company and
Penang Water Authority.
9
It is understood that since 1999, the Inter-Department
Committee on Dam Safety has not been operating.
Transfer of Technology and Special Training in
Dam Engineering
Immediately after Merdeka, the bulk of the engineers upon
graduating from overseas or University of Malaya (being the only
university at the time) were taken in to serve the Government,
under the Malayanisation Programme to replace expatriates in
the Government service. However, a few joined foreign irms of
consulting engineers based in the country or newly established
local consulting engineering irms. These engineers formed the
core of local engineers in the private sector including the pioneers
in geotechnical works involved in the large dam schemes such
as the Cameron Highlands hydroelectric schemes (1959-1963),
Penang-Air Itam dam for water supply scheme (1963-1965) and
MADA irrigation project (1666-1970) in Kedah.
During the subsequent years in the 1970s to the 1990s, a
number of the foreign owned irms were taken over by Malaysian
engineers and among such irms involved in dam engineering
were SMHB Sdn Bhd, SSP, and Ranhill Bersekutu. Among
the locally established irms with background experience in
dam engineering were JKC, KTA Tenaga, Angkasa Consulting
Services and RPM engineers. These local engineers received
in-house peer training and also gained considerable experience
through transfer of technology from their overseas associates.
For the future, it is considered appropriate for new irms
intending to be involved in dam engineering to have engineers
specially trained and qualiied for design, supervision of
construction, environmental and safety inspection of dams.
These engineers may need to be accredited possibly with a
yet to be formed ‘Government Commission on Dams’. This is
particularly important as far as dam safety is concerned. The
consequential effect of failure of dams can be disastrous causing
loss of lives to entire villages and townships and to properties
downstream of the dams.
3.0 MAIN ISSUES OF CONCERN IN DAMS,
ENVIRONMENT AND DEVELOPMENT
IN MALAYSIA
Introduction
Malaysia has undergone rapid economic development since the
1960s after achieving independence from Great Britain. A series
of 5-year development plans have been implemented with the
current 10th Malaysia Development Plan due for completion
in 2015. Ensuring adequate supply of water resources remains
a key prime mover in the much needed development of the
country to meet the rising demands of the increasing population,
the requirements of the fast expanding industrial development,
irrigated agricultural needs and for energy generation in the
hydro-electric process. The increasing demand of water is shown
in Table 3.1 and for energy in Figure 3.1 (Generation Mix) which
indicates increase in electricity demand from 2015 to 2030. It is
interesting to note that hydroelectric source is projected to be
23% of the Generation Mix when the total demand increases
from 121,000 GWh in 2015 to 211,000 GWh in 2030.
Due to climatic condition in the country where, sometimes,
prolonged dry periods take place, adequate storages are
provided to ensure stability in the supply of water. Like other
countries, Malaysia highlights that damming of rivers, where
economically and socially feasible, is still an important priority
for water managers and policy makers. It is a convenient and
most feasible way to solve and meet evolving water and energy
needs by building dams. However, since the past two decades,
another issue emerges in the immediate need to protect and
conserve the environment particularly in the provision of dams
and storageswhere extensive area of fertile land and forests are
inundated permanently with water.
So the issues of concern is not only on freshwater scarcity,
causing a crisis, but also on adverse effect, caused by a remedial
measure in the provision of dams, to the environment. To put
Table 3.1
TOTAL CONSUMPTIVE WATER DEMAND ( MLD)
Perlis
Kedah
Pulau Pinang
Perak
Selangor
Negeri Sembilan
Melaka
Johor
Pahang
Terengganu
Kelantan
Pen. Malaysia
2010
837
8,006
2,096
5,342
6,133
932
885
1,958
1,990
2,421
4,472
35,065
2020
819
8,152
2,271
5,267
6,823
989
1,003
2,410
2,594
2,671
4,435
37,427
2030
783
7,785
2,289
4,927
7,041
982
1,030
2,832
2,455
2,657
4,344
37,137
2040
778
7,871
2,395
4,933
7,561
1,002
1,120
3,189
2,495
2,736
4,385
38,481
2050
771
7,881
2,450
4,962
8,005
1,026
1,202
3,563
2,624
2,811
4,393
39,680
Sabah
FT Labuan
Sarawak
Sabah. FT Labuan & Sarawak
2,501
49.29
2,898
5,429
3,712
65.89
5,933
9,719
3,813
71.05
5,830
9,719
3,954
75.79
5,967
9,990
4,035
79.28
6,171
10,262
Total Malaysia
40,512
47,128
46,856
48,488
49,938
Source: Adapted from Review NWRS 2000-2050 (2012) using Mld conversion
10
everything in the right perspective, the inal issue of concern,
at the moment, is the absence of an effective coordinating
mechanism at the national level to initiate, develop and monitor the
implementation of policy reform that are of national signiicance
and requires cooperative action by State Governments. This
mechanism can also be responsible for legislation on dam safety
and regulation on provision of dams that includes the design and
maintenance of dams for the country similar to what is being
practiced in developed countries like Australia, South Africa,
South Korea and Europe.
in Peninsular Malaysia (Reference Table 3.2 and graphically
Figure 3.2).
These shortages are, in fact, being managed at above stress
level mainly by regulated releases from storages impounded by
dams as additional water required during dry periods. The role
played by dams is certainly vital to maintain a consistent supply
of freshwater for use throughout the year.
Security of water resources is very much dependent on climatic
conditions. Although Malaysia is among the countries with
high average annual rainfall, it is however, seasonal and very
Figure 3.2
Table 3.2
Figure 3.1
Source: EPU - Malaysia Energy Outlook 2010-2030
Pre-empting Water Crisis
The new study on Asia-Paciic region water security warns
that many countries face an imminent water crisis unless steps
are taken immediately to improve their management of water
resources (ADB-Asia Paciic Water Forum). “As a whole the
region is faced with a number of unique challenges – most
notably rapid urbanization and industrialization. The region’s
huge population is also very exposed to the expected impacts of
climate charge” (Makin ADB).
From a UN data, Malaysia is among the handful of Asian
nations largely free of water stress at present. However, the
threat of scarcity of freshwater in the near future is already there.
The main issue of concern is to address this threat and pre-empt
it from happening.
Addressing scarcity of freshwater resources
The threat of scarcity of freshwater resources is as shown in
Figure 3.2 (NWRS Review : 2000-2050) where consumptive
water demand (irrigated agriculture and potable water supply) is
increasing whilst unregulated low is decreasing. This alarming
situation, if unchecked on time, would result in serious water
shortages in the immediate future. Some parts of the country
are already experiencing unregulated low freshwater deicit, as
shown in Table 3.2. The deicits are in Perlis, Kedah and Penang
(irrigated agriculture and potable water supply and in Selangor
and Melaka (potable water supply). Melaka is already importing
water from Johor to augment the storage and Selangor will soon
be using water from Pahang. The total deicits in the ive states
is calculated to be 4,202 MCM (11,512 Mld) which is about
28.4 per cent of the total Malaysian demand of 14,787 MCM
(40,512 Mld) in 2010 (or 32.8 per cent compared to total demand
pronounced. In an extreme case during the water crisis in
Selangor in 1998, there was hardly any rainfall for nearly
six months resulting in a severe drop of lows in rivers and
waterways. Occurrences of lood is more frequent, particularly
on the east coast of Peninsular Malaysia during the monsoon
season. Adequate storage is deemed necessary. The main
issue is the ability to harness and store the excess rainfall for
use effectively over the remaining period of the year whilst
concurrently attending to lood mitigation measures in dams like
large hydroelectric reservoirs as multi-purpose dams.
The issue of water scarcity is global. By 2025, two-thirds
of the global population could confront water stress (FAO “Hot
issues : water security 2012) – the vast majority would be in
Asia. While Asian freshwater resources have remained the same,
its population has grown from nearly 1.5 billion in 1950 to 4.2
billion by end of 2011 or 60 percent of the world’s total (UNDP
2011). Asia’s rivers, lakes and aquifers give it, per capita,
barely one tenth the water of South America or Australia and
New Zealand, less than one-fourth of North America and nearly
one-third of Europe (FAO IRWR 2011). Yet the world’s fastestgrowing demand for water for food and industrial production
and water supply is also in Asia.
11
The decision lies on whether developing Asian nations would
have the capacity to emulate many of the advanced countries to
build large dams in order to strengthen the high capita storage
capacity needed for human development and economic growth.
China, as the fast growing developing country, and second largest
economy in world, has embarked on construction of many large
dams. In the case of Malaysia it is interesting to note that based
on computation of the total storage volume of 86,763 million m3
and the current population of 29 million, the per capita storage
is 2,992 m3 when compared to Australia’s 4,600 m3 and North
America’s 6,000 m3.
Environmental
Sustainability
and
Social
Conditions
of
Where large quantities of water are needed for potable and/or
industrial water supply, irrigation, energy and lood control,
multipurpose dams have proven to be the best solution. Once
these dams are completed, they become an integral part of the
environment. It is essential that environmental assessments be
made to identify potential impact by the project. From social
aspects, public involvement early in the project planning process
also allows the affected people not only to better understand
the project but plan for and obtain assistance for real estate
acquisition and resettlement. It is an acceptable practice that
people who have to be resettled must have a better quality of
life than they have before and also better facilities. All necessary
expenses for such settlement practices should be included in the
project cost.
Central to issues on the development of dams in Malaysia
is the effect it has on water resources lies on inadequate
environmental and social consideration when planning of the
project. Perhaps if the planning and study period is spread over a
reasonably longer period of at least ive years or more before the
project is started, most issues of concern would be scrutinized
and agreed to everybody’s satisfaction and adverse impacts
reduced to absolute minimum.
The environmental impact of dams are wide ranging and can
be briely summarized as follows:
i. Habitat fragmentation within dammed rivers;
ii. Downstream habitat effects caused by altered lows, such
as loss of loodplains, riparian zones, and adjacent wetlands
and deterioration and loss of river deltas and ocean estuaries;
iii. Deterioration of irrigated terrestrial environments and
associated surface waters;
iv. Reduction of river lows, leading to reduced water quality
because of dilution problems for point and non-point sources
of pollution;
v. Genetic isolation of species as a result of habitat
fragmentation;
vi. Changes in ecosystem-level processes such as nutrient
cycling and primary productivity;
vii. Contamination of food webs, and
viii. Increase in greenhouse gas emissions.
One example of note is the Three Gorges Dam in China.
Constructed in 2006, the dam was completed and became
functional by July 2012. The environmental impacts are
certainly worth noting when considering the beneits of
considerable hydroelectric power (22,500MW). The irst impact
is the water pollution created the submergence of hundreds of
12
factories, mines and waste dumps, and the presence of massive
industrial centres upstream. Second, erosion of the reservoir and
downstream riverbanks is causing landslides, and treating one
of the world’s biggest isheries in the East China Sea. Third, the
weight of the reservoir’s water has many scientist concerned
over reservoir-induced seismicity. Finally, crisis have also
argued that the project may have exacerbated recent droughts
by withholding critical water supply to downstream users and
ecosystems, and through the creation of a microclimate by its
giant reservoir. In 2011, China’s highest government body for
the irst time oficially acknowledged the “urgent problems” of
the Three Gorges Dam.
Equally of major concern in the resettlement of people from
the area to be inundated as reservoirs. Some form of resettlement
programme has to be drawn up during the planning and study
period. In Malaysia, many of the programmes have either
been unsuccessful or met with implementation problems. For
instance, many Orang Asli communities have been provided
with alternative housing which is built of concrete structures in
land areas that are void of forest vegetation. Such housing are
unsuitable for the Orang Asli who are used to living in wooden
houses among tall trees.
To quote actual examples of dams that have been built in
Malaysia and some of their effects on the environment and
communities, two dams are cited, namely Sg. Selangor dam in
Hulu Selangor and Kelau Dam in Pahang.
For the Sg. Selangor Dam, because the project was in
Selangor where public is more vocal and more aware of
environmental issues, there was much protests from various
NGO groups during the early stages of the project. Now, some
12 years after the implementation of the dam, the actual outcome
of some of the earlier major concerns can be summarized as
follows:
• Relocation of about 340 Orang Asli in Kg. Gerachi and
Kg. Peretak – in this case there was emphasis placed on
providing the Orang Asli communities with suitable housing
which was designed to be of wooden structure, more like
kampong houses. There are nevertheless still issues in the
implementation programme due to inadequate follow up on
their livelihood, schooling programme for the children, etc.
• Impact on irely colonies in Kg. Kuantan located at the river
mouth about 80 km downstream of the dam – this was one
of the key issues of concern of the Sg. Selangor dam. The
Malaysian Nature Society had been monitoring the irely
colonies after the dam was constructed and their inding was
that the colonies have been dwindling. However, this may
not be completely due to the dam project along since there
are also other activities at the estuary areas that could be
affecting the mangrove ecosystem.
In the case of the Kelau Dam project in Pahang, the dam
construction is currently ongoing. The main issue relating to
this project is again the resettlement of Orang Asli communities
affecting about 110 people. The resettlement package for the
Orang Asli includes concrete houses, 5 acres of oil palm areas and
monetary compensation for 4 years. This is part of Government’s
“Program Pembasmian Rakyat Termiskin”, (PPRT) programme.
There are already problems with the execution of the resettlement
programme; the oil palm areas are poorly managed, the houses
are in areas that are completely cleared of vegetation, the
drainage systems for the housing area have already collapsed,
and there is no waste collection provided for the settlement area.
As a result some of the Orang Asli families have moved back to
near where they used to live before.
Resettlement programme must involve educational proposals
and new activities such as crafts or other cottage industries to be
developed.
Effective Governance
Management
of
Water
Resources
Another main issue of concern is the confusion over responsibility
for governance. “Many countries still have multiple agencies
with responsibilities for water. This often leads to ineffective
planning and utilization of available resources, including water,
human and inancial resources. I cannot think of a country in
the region that would not beneit from a long hard look at the
institutional arrangement for water planning and management”.
(Makin ADB).
Management of water resources is a state responsibility in
Malaysia and of late, a number of states has instituted some form
of arrangement for improvement to water resources and water
demand management with a varying degree of success. The state
of Selangor, with the formation of Lembaga Urus Air Selangor
(LUAS), has for sometime established a system of governance,
which would be a suitable model for other states to adopt. Among
the responsibilities are:
• The conservation, replenishment and supply of water
• The beneicial use of water
• determining and recording the actual availability of water
resources within the state,
• protection of water from pollution and the improvement of
its quality
• equitable distribution of water by allocating the rightful use
of water to users for different purposes broadly based on the
principle of IWRM
• protection of the environment
At the National level, there has yet to be an effective Advisory
Mechanism on eficient Water Resources Management across
the whole range of users based on IWRM principles. The users
are irrigated agriculture, potable water supply and sewerage,
hydropower, lood management, environment, isheries,
transport and others. This mechanism, among others, can
provide guidance and advice on policy matters, human resources
training, research and development and investments on capital
and operational works.
A good example, for reference, is the way the Council of
Australian Governments (COAG) water reform is being made
to work in Australia. The role of COAG is to initiate, develop
and monitor the implementation of policy reforms that are of
national signiicance and which require cooperative action by
Australian governments (State Governments).
The responsibility in water resources management lies with
the State Governments. Water resources can become a National
Issue when shortages in supply are widespread throughout or
some parts of the country. In such a case, the role of the Federal
Government, represented by a Mechanism, becomes important
to provide coordination among the states and setting direction to
overcome any issues and problems of national importance. This
Mechanism should preferably be independent, sector-neutral
and high level. With the formation of this mechanism, important
issues of dam safety can be addressed, through legislation and
applied uniformly throughout the country.
•
•
•
•
•
•
•
•
General issue of concern in management
To change from Supply to Demand Management
From Sectorial to IWRM
Federal-State coordination
Inter-state coordination
Inter-Ministry coordination
Public Participation
Driving Business Development and Wealth Creation
Driving Science, Technology and Innovation (STI)
Speciic Issues of Concern
• Water security and, consequently, food security are important
concerns which need to be carefully balanced with the likely
negative social and environmental impacts they can cause.
• Dam safety – the need to have legislation in the provision
of dams to ensure that dams are properly and adequately
designed, maintained and regularly inspected by providing
standard practices including rules and regulations
• Moving towards a more inclusive approach to tackling water
pollution issues has long been recognized as a positive step
: but turning this into a practical reality requires social
evidence for what works well at catchment scale.
• Launching of water certiication standard (eg.UK-based
Carbon Trust) – a Water Standard to help drive the move
to resource-eficient economy, requiring to produce at least
two years of data abstraction.
• Promoting close linkages among the sectors, such as, water
and energy. Water is not only essential for large-scale
electricity consumption and production but also the water
sector is a major consumer of electrical power.
• Promoting the provision of multi-purpose dams as a mean
to manage demands on use of water in the overall water
resources management.
Summary of Conclusion
•
•
The main issue of concern facing Malaysia is scarcity
in freshwater resources. At the moment, this is being
experienced in the ive states of Perlis, Kedah, Penang,
Selangor and Melaka. There are normally large bodies of
water downstream of rivers which are severely polluted.
The situation may become serious with the imminent impact
of climate change. For a long time in the past, provision of
dams and storages has been given priority in solving water
shortages and has played an important part in water sources
regulation in the states concerned. Some amount of recycling
has also been adopted for irrigated areas.
Reservoirs impounded by the dams inundate extensive areas
of forest and fertile lands permanently and cause adverse
effect to lows in the river regimes. The initial issue before
the construction of the dam is to satisfy the environmentalist
and social activists that any adverse effect will be minimized.
At planning stage, suficient time should be allowed (5 years
or more) for reconnaissance work identifying suitable sites
for dams. At the later stage when the dams are in operation,
the dam owners are obligated to ensure that the river lows
are kept to at least, the normal lows before dams make their
appearance. The dam owners are to ensure that dam safety
units are set up for the regular monitoring and surveillance
functions. Safety review by independent and properly
qualiied engineers is strongly recommended.
13
•
Malaysia needs a mechanism at the highest national level to
provide an independent, sector-neutral effective leadership
and drive in water resources management. There is also need
for private sector participation, principally as stakeholders,
if water resources management is to be successful.
4.0 MAxIMIZING SUSTAINABILITY IN
THE CONSTRUCTION AND OPERATION
OF DAMS
HSAP is an evidence-based objective assessment of a
project’s performance, prepared by an accredited assessor
applicable to all stages of hydropower development in all
global contexts. Therefore, it is plausible that the HSAP could
be integrated into Malaysia’s current EIA processes to help
site areas for dams that will limit the environmental, social and
economic upheaval. Furthermore, the preparation of HSAP
involved participation of leading NGOs including WWF, The
Nature Conservancy, and Transparency International. NGO
participation provides further legitimacy and helps to ensure all
aspects of sustainability are being properly examined.
Introduction
Despite efforts to achieve Integrated Catchment Management,
it is conceivable that dams will be required in the future to meet
societal needs. If this is the case, what process can be followed
to ensure that the most sustainable outcome is achieved when
considering the vast array of technical, environmental, social
and economic challenges that exist with a new or existing dam
project?.
The emphasis on sustainability has relevance in Malaysia
considering the challenges involved in siting a dam. There are
numerous issues to contend with and past experiences of dam
building in the country have often faced dificulties related to
community resettlement and environmental degradation. Whilst
there are existing regulations in place to assess the sustainability
implications of a dam (i.e. Environmental Impact Assessment),
these could be enhanced with the latest developments in current
dam building practice. This next section briely sets out a process
of determining the most sustainable outcome for hydropower
projects.
The Hydropower Sustainability Assessment
Protocol (HSAP)
The Application of HSAP
A wide application of the Protocol is desired by the IHA and
they argue it should be applied in a collaborative way, to
ensure the best availability of information and points of view.
The development and evaluation of a hydropower project will
involve many actors with different roles and responsibilities. It
is recognized that both development and operation may involve
public entities, private companies or combined partnerships, and
responsibilities may change as the project progresses through its
life cycle.
In sum, HSAP provides developers and relevant stakeholders
(i.e. government agencies, non-governmental, community
groups) with a necessary tool kit so that they are asking the
right sustainability questions across a number of topics. If
these stakeholders are unsure of the most suitable site for dams
between a number of different sites, the HSAP provides them
with a way to determine the most sustainable and in which areas
they need to augment poorly performing aspects of the project.
Potential application of HSAP in Malaysia
Developed by the International Hydropower Association (IHA)
and launched in 2011, the Hydropower Sustainability Assessment
Protocol (HSAP) is a sustainability assessment framework
for hydropower development and operation. It enables the
production of a sustainability proile for a project through the
assessment of performance within important sustainability
topics. Sustainability in this context refers to aspects related to
the environment, society, economy, technical and integrative
aspects. While HSAP is focused towards hydropower projects,
the process of site selection, engineering design and project
operation has relevance in determining suitable sites for dams in
Malaysia. Table 4.1 provides an overview of the sustainability
criteria and Figure 4.1 shows an example of the scoring ‘spider
diagram’.
Any future application of HSAP in Malaysia could be
undertaken alongside the current regulatory framework for dam
selection and associated environmental and social assessments,
including the Environmental Impact Assessment (or EIA).
The current regulations relating to Environmental Impact
Assessment is stipulated under the Section 34A Environmental
Quality Act 1974, Environmental Quality (Prescribed Activities)
(Environmental Impact Assessment) Order 1987. Dam projects
are Prescribed Activities under three categories:
i. Schedule 3 – Drainage and Irrigation: (a) construction of
dams and man-made lakes and artiicial enlargement of
lakes with surface areas of 200 hectares or more.
ii. Schedule 13 – Power Generation and Transmission: (b)
dams and hydro-electric power schemes with either of both
Table 4.1: Sustainability criteria for dam builders as prescribed in the HSAP
TECHNICAL
ENVIRONMENTAL
Siting and
Downstream lows
Design
Hydrological Resource Erosion and sedimentation
Reservoir planning,
Water quality
illing and management
Biodiversity and invasive
Infrastructure safety
species
Asset reliability and
Waste, noise
eficiency
and air quality
SOCIAL
FINANCIAL AND
ECONOMIC
Project affected communities
Economic viability
and livelihoods
Resettlement
Financial viability
INTEGRATIVE
Downstream need and strategic it
Communications and consultation
Indigenous people
Project beneits
Governance
Cultural heritage
Procurement
Integrated project management
Public health
Environmental and social issues
management
Source: International Hydropower Association
14
Figure 4.1: Example of a scoring ‘spider diagram’ for an individual dam
Source: International Hydropower Association
of the following:- (i) dams over 15 metres high and ancillary
structures covering a total area in excess of 40 hectares and
(ii) reservoirs with a surface area in excess of 400 hectares.
iii. Schedule 19 – Water Supply: (a) construction of dams or
impounding reservoirs with a surface area of 200 hectares or
more.
The Hydropower Sustainability Assessment Protocol (HSAP)
appears to be a good tool for site selection exercise whereby
environmental, social and economic factors are included in the
decision to site a dam. The HSAP would be most appropriate
to be used during the masterplanning stage when preliminary
investigations are made to identify sites for dams. For instance,
for water supply dams, the water resources masterplan studies
identify dam sites which are recommended to be gazetted for the
purpose. The HSAP tool could be used for such studies.
In Malaysia, the EIA process usually takes place once the
dam site has already been identiied and using the HSAP at this
stage is almost too late for a change in the site. The EIA identiies
the impacts and make recommendations to mitigate the impacts,
which is more a corrective rather than a preventive means of
minimizing environmental and social issues. In most cases, the
EIA is conducted in tandem with the engineering design and
at this stage, the project proponent (usually the government
authorities) is already quite committed to the implementation of
the project and would have already invested time and cost.
Having said that, recently the DOE has included an additional
step in the EIA process which is the requirement to conduct a
Preliminary Site Assessment (PSA) and submit the PSA to
the DOE before embarking on the full EIA study. The HSAP
process could be a useful tool in the PSA stage. However, the
PSA process is a fairly simplistic assessment without involving
the participation of an independent expert and auditor which is
the concept of the HSAP.
The HSAP could provide a more comprehensive assessment
of potential sustainability impacts than the PSA and, moreover,
if successfully adhered to, provides the developer with a
certiication standard of international standing.
5.0 FUTURE OUTLOOK OF TOMORROW’S
DAMS TO ACHIEVE SUSTAINABLE TARGET
Introduction
For a long time dams have been the most obvious option in
meeting development objectives. Over the past 5,000 years,
more than 50,000 large dams have been completed. Throughout
history of the world, dams and reservoirs have been used
successfully in collecting, storing and managing water needed
to sustain civilization.
Construction of dams gathers momentum since 1900s when
more than 60% of the dams have been built as shown in Figure
5.1. Most of the construction has taken place in industrialized
countries where need for water grows tremendously beyond
the basic needs in food production, drinking water supply
15
In operation up to 1999
8000
7000
6000
5000
4000
3000
2000
1000
0
<
1900
1900- 1910- 1920- 1930- 1940- 1950- 1960- 1970- 1980- 19901909 1919 1929 1939 1949 1959 1969 1979 1989 1999
Figure 5.1
Source: Dams and Reservoirs, Societies and Environment in the 21st Century
(22 ICOLD International Conference 2006)
and lood control measures. The era of intensive development
in industrialized or developed countries calls for massive
energy requirement which relies a lot of energy provided by
hydroelectric generation. More than 80% of the world reservoirs
storage is used for hydropower.
However, over the past three decades there has been
a dramatic decline in dam investment in industrialized or
developed countries. This is possibly due to stabilization in
demand for water and energy in developed countries and also
resiting of some heavy industries to developing countries
possessing extensive energy potentials like hydroelectric power.
The present total storage is about 6,800 km3 (billion m3)
and is estimated to increase by 2,500 km3, i.e. around 40% up
to 2050. A further increase of 1,000 or 1,500 km3 after 2050 is
likely, as shown in Table 5.1.
The probable huge increase in oil costs, the likely premiums
to clean energy may provide impetus to building more
hydroelectric dams in large countries like China, India, Brazil,
Russia and Congo.
Before 1970, for dams as for other human activities, there
was little concern for the environment. For now, the possibility
to build dams is made more dificult in view of actions of some
opponents. Critics to large hydraulic structures, particularly to
large dams often argue that economic and social development
can also be achieved without them. It is the intention in this
presentation to address this issue based on available alternative
options which can be used. The two main environmental
drawbacks of dams are large impounded areas and, in some
cases, the withdrawal of most of the river water throughout the
year. Besides studying the possible alternative options to large
dams, the dissemination of fair and balanced information on the
beneits of the dams and the management of these drawbacks are
thus essential.
Table 5.1
2000
2050
2100
a) Irrigation, water supply,dry season releases, lood
mitigation, part for hydropower (50%)
YEAR
1200
2400
3000
b) Hydropower alone
3000
3600
4000
c) Siltated storage and unsiltated dead storage
2600
3500
4000
Total
6800
9500
11000
Source: Dams and Reservoirs, Societies and Environment in the 21st Century
(22nd ICOLD International Conference, 2006)
16
Dam Development in Developed Countries
Most developed countries turned to large dams to help them
in their industrialization development to meet escalating
water, energy and other demands from the 1930s to the 1970s.
Compared to the rest of the world, they had a headstart in dam
building and this reached a peak in the 1970s when 7000 dams
were constructed as seen in Figure 5.1. On average two or
three new large dams were commissioned each day somewhere
in the world. The water that is stored and regulated by dams
and reservoirs produces irreplaceable water resources and
apart from water and energy demands, also brings beneits to
lood mitigation, river navigation, recreation, tourism and the
environment. Globally, this represents 30% of the world’s
available water resources which reaches the end users. However
over the past three decades there has been a dramatic decline in
dam investment in developed countries.
Over this same period, partly due to pressure from anti
dam movement, the world is looking for a balance between
the beneits and the environment for water resources projects.
The challenge for the future will be the utilization of dams in
conjunction with the climate, environment and land use as part
of social and economic development goals, crucial to achieving
sustainable and inclusive growth of which natural aquatic
ecosystems are considered as an integral part.
Dam Development in Developing Countries
Many developing countries started building large dams after
World War II and are still building more in order to meet the
increasing water and energy demands for now and the future. As
shown in Figure 5.2, the top ive dam-building countries account
for more than three quarters of all large dams worldwide, with
approximately two-thirds of the world’s existing large dams
found in developing countries. Being late starters in dam building,
inevitably, they face the full force of anti-dam movement of the
world which became active after 1970s.
Among developing countries, Malaysia has to date
constructed 69 large dams, of which 66 were constructed after
United States - 6,575
14%
India - 4,291
9%
World War II and has plan to build 73 more by 2050 (Review
of NWRS 2012 and other reports). About 95% of the reservoir
storage is used for hydropower.
Malaysia has undertaken ten Five-Year Economic
Development Plans (EDP) successfully and has ensured that
there is suficient quantity of water supply for development in
agriculture, domestic and industrial uses. For the same period,
storages were provided for hydro-electric generation. Timely
commissioning of dams under the various stages of the EDP has
assisted in the stability in the supply of water resources for the
economic development and water security of the country. It is a
credit to the country that Malaysia has maintained water security
at all time with the continued implementation of EDP. This is
crucial in achieving sustainable and inclusive growth.
Adverse Impacts of Dam
Worldwide, dams have been accepted as an important means
of meeting perceived needs for water and energy services and
as long-term, strategic investments with the ability to deliver
multiple beneits. Some of these beneits include job creation,
creating income from export earnings by selling cash crops
or processed products. In many cases an unacceptable and
often unnecessary price has been paid to secure those beneits
especially in social and environmental terms.
The generic nature of the impacts of large dams on ecosystems,
biodiversity and downstream livelihoods is increasingly well
known. Increased attention is now given to avoidance or
minimization of ecological impacts. A number of developed
countries, particularly in the USA, ecosystem restoration is
being implemented as a result of the decommissioning of dams.
It is possible that impacts of large dams have yet to reach a
serious level in Malaysia. The question is what about what may
unfold in the future if more dams are built. Perhaps lessons can be
learnt from China, which along with India is now building most
of the large dams among developing countries. Can developing
countries like Malaysia manage suficiently well without dam?
Japan - 2,675
6%
Spain - 1,196%
3%
Others - 7,372%
70%
Others
23%
France - 569
4%
Brazil - 594
4%
China - 22,000
45%
Turkey - 625
4%
Canada - 793
9%
South Korea - 765
9%
Figure 5.2: World population of dams, by country
Source: World Commission on Dams (WCD) estimates, based on ICOLD and Other sources
17
Other Options to Dam Building
Opponents of large dams contend that better, cheaper, more
benign options for meeting water and energy needs exist and
have been frequently ignored. Dams have often been selected
over other options that may meet water or energy goals at
lower cost or that may offer development beneits that are more
sustainable and more equitable.
For Malaysia, several options to dam building for water and
energy resources development to meet sustainable energy, water
and food needs currently exist as shown in Figure 5.3.
• Stakeholder Engagement: Promoting IWRM is now
widely accepted internationally as central to effective
management of water resources. Although accepted by
the Government for adoption more than 20 years ago, the
results have not been satisfactory. Getting all parties to be
Stateholder Engagement
Promoting Integrated
Water Resources
Management (IWRM)
Utilize Latest
Research
Demand-side
Management Water
Demand Management
(WDM)
Surface Water
Management
Other Options For
Water and Energy
Resources
Development
Groundwater
Utilities
Supply-side
Eficiency
Infrastructure
Management
Figure 5.3: Other Options for Water and Energy Resources
Development
•
•
•
18
involved in an integrated manner in water management can
assist in solving major water problems like keeping clean
(to acceptable standards) large bodies of water in rivers and
lakes and maintaining them in good conditions, for use.
Surface Water Management: Improve the management
of surface water in order to utilize this resource more
effectively, including improving the surface water quality
and tackling pollution. This includes examining how best to
manage current surface water sources through the legislative
and regulatory frameworks. The diesel oil spill into Sungai
Selangor in August 2013 is a case in point: the incident
reveals a breakdown in the enforcement and monitoring of
polluting industries in the Malaysian urban context.
Supply-side eficiency: This can include interbasin transfers, recycling and reuse of water and new
supply alternatives like renewable energy options.
Where practicable, there should be provision in raising of
existing dams to store more water instead of planning for
more dams. As far as possible, more existing dams should
be converted and used as multi-purpose dams.
Infrastructure
Management:
Manage
existing
infrastructure to minimize water losses, such as reducing
non-revenue water (NRW) from illegal connections and
damaged pipelines. Malaysia treats approximately 14,000
mega litres a day in 2011: however, nearly 37% does not
reach consumers (Malaysian Water Industry Guide 2012).
In contrast, neighbouring Singapore reports an NRW value
of just at 4.6% (Asian Green Index, 2011). This issue
highlights not only the considerable waste of water but the
waste of energy and chemicals required for the treatment
process.
• Groundwater Utilization: Determine the opportunities for
groundwater extraction, including critical research to derive
the extent of sources and treatment technologies required.
• Water Demand Management (WDM): Implementation
water demand management strategies to reduce the need for
water. Such techniques include education of water users to
minimize their consumption and encourage installation of
water eficient technologies (i.e. half lush on toilets, push
taps). This can be supported by considering the economies
of water supply, including revisions of the current water
tariff. Examples of water demand management in action
include programmes in the Murray-Darling Basin, a water
scarce region in Southeast Australia. Here, an integrated
programme was devised to support better use across the
major industrial and agricultural user groups, as well as
including a plan for residential users too.
• Utilize Latest Research: Recent developments in the ield
of ‘water footprint’ to allow a better understanding of the
extent of our water quality and quantitative impacts related
to water production and consumption. Determining a ‘water
footprint’ for the Malaysian Water Industry as a whole may
help to justify more sustainable strategies and approaches.
All these alternative options are not easily implemented but if
successfully put in use can question the wisdom in building more
dams. But can this happen?
Some of the alternative options make economic sense and
merit special attention listed as follows:
► Demand-side management (WDM)
Options for water supply hinge on demand-side management
(WDM) in reducing usage and wastage and eficient
distribution and accounting for water supplied to end users
In the case of potable water supply, any reduction in per capita
usage means saving in water usage and reducing wastage.
Correspondingly, a better management in water distribution can
cut down on water losses considerably. As an example, Table
5.2 indicatively shows a potential saving of at least 1600 Mld in
potable water supply in 2020 in Peninsular Malaysia assuming
a 15% reduction in per capita demand and a 6% reduction in
losses.
In the case of agricultural water usage, particularly
paddy cultivation, a small reduction in water usage can free a
considerable amount of water for other end users, like domestic
and industrial supplies and for environment and recreational
beneits.
Efforts to develop varieties that require less water is currently
on going. In the mean time, efforts to increase irrigation eficiency
has to be stepped up. As an example, as shown in Table 5.3, the
total paddy crop water requirement for the MADA Granary is
0.011 MCM/ha for the main season and 0.013 MCM/ha for the
off season. Thus the total crop water requirement is equivalent to
0.024 MCM/ha/year. Rainfall provides 52% (0.0125 MCM/ha)
of the total water needs and the remaining 48% (0.0115 MCM/
ha) is from non-rainfall sources namely the dams (32%), rivers
(10%) and re-use (6%). With a total area of 96,558 ha, then the
total crop water requirement is 2,317 MCM/year. Since 52%
of this amount 1,205 MCM is from rainfall and the remaining
48% or 1,112 MCM has to be from irrigation. Presently, MADA
irrigation system is reported to be operating at 70% irrigation
eficiency. This means that the irrigation supply to produce rice
here is 1,588 MCM/year. If irrigation eficiency is raised to
75% (an on-going effort), then the total irrigation supply would
be 1,483 MCM/year, a reduction of 105 MCM/year. This is
equivalent to a relief of 288 MLD for the water supply industry.
Assuming a domestic and industrial consumption rate of 250
litres/day/capita, this savings from irrigation could satisfy water
supply requirements for about 1.2 million population. Estimating
that the populations of Kedah, Perlis and Pulau Pinang now are
nearly 2.3, 0.7 and 1.7 million (2015) respectively or a total of
4.7 million, this saving in irrigation represents nearly 25% of the
water supply requirements of the population in the three northern
states.
► Supply-side management in eficient inter-basin water transfer
Inter-basin water transfers have solved a number of vital
water shortage cases in Peninsular Malaysia in recent
years. The most notable completed project in the transfer
of water from the Sg. Muar to Melaka to meet the shortfall
in potable water supply in 1991. Catchment water transfers
Table 5.2: Reduction in per capita consumption and water losses
YEAR 2020
Projected Potable Water Demand (MId)
For Malaysia
a) Per capita demand
Assuming 50% as domestic and
15% reduction in per capita demand
For Peninsular Malaysia
Correspondingly reduction in per capita demand
b) Water losses
Assuming 50% as domestic and
6% reduction in losses
For Peninsular Malaysia
and 6% reduction in losses
TOTAL (a) + (b)
18,618 MId
9,309 MId
8, 046 MId
1, 123 MId
9,309 MId
8,046 MId
483 MId
1,606 MId
Source: Demand Projection: Review of NWRS (2000-2050)
Table 5.3: Irrigation water saving through eficiency improvement
POTENTIAL WATER SAVINGS IN IRRIGATION
(AN ILLUSTRATION) – THE MADA GRANARY
A. Estimated Total Paddy Crop Water Requirement
0.011 MCM/ha
a) Main Season
0.013 MCM/ha
b) Off-Season
0.024 MCM/ha
c) Total Annual
B. Total MADA Granary Area
C. Total Annual Crop Water Requirement
(A(c) x B)
96,558 ha
2,317 MCM
D. Sources of Water
a) Rainfall (52% x C)
b) Non-Rainfall (48% x C)
1,205 MCM/yr
1,112 MCM/yr
E. Irrigation Supply
a) Present Irrigation Eficiency
b) Thus Irrigation Supply (D(b)/E(a))
70%
1,588 MCM/yr
F. Potential Savings
a) Increasing Irrigation Eficiency to
b) Irrigation Supply (D(b)/F(a))
c) Irrigation Supply Savings (E(b)-F(b))
75%
1,483 MCM/yr
105 MCM/yr
have been known to take place in hydroelectric generation.
One example is in the Cameron Highland Scheme, where
augmentation of water supply comes from upper reaches of
Sg. Kelantan at Sg. Plauur to Ringlet completed in 1963. It
is possible that such similar schemes may take place in the
future, particularly, the transfer of water from existing dams
in water rich states to recipient’s states needing water.
► Regulating reuse and recycling of water, potentially,
as augmented supply to available water resources.
One of the greatest opportunities for water reuse is to
supplement or replace the potable water or freshwater
demands of industries and other commercial uses. The
industry is the second largest market for water supply
after agriculture, accounting for around 25% of global
demand. The milestone in the development of safe
water reuse practices are as seen in Figure 5.4 and are
based on the advances in waste water treatment with the
technological break through in of membrane iltration.
In developed countries an important new concept in water reuse
is the ‘it-to-purpose’ approach which entails the production
of recycled water of a quality that suits the end users. Figure
5.5 (Asano 2002; Lazarova et al., 2013) shows the sequence
treatment and reuse for the main categories of water reuse.
Water reclamation and puriication technologies exist
to produce pure water of almost any quality desired,
including puriied water of quality equal to or higher
than drinking water (IWA Lazarova et al., 2013).
In Malaysia, this potential supply should be closely studied
with particular reference to treated efluent discharges
in built-up areas in Selangor, Kuala Lumpur, Putrajaya,
Johor and Penang where there is scarcity of unregulated
water resources (Review of NWRS 2000-2050). The total
potential augmentation from treated wastewater efluent is
estimated to be about 14% of total water demand for these
states as shown in Table 5.4. (Using data from Malaysian
Water Industry Guide (MWIG 2012).
Similarly, if focus is given to Selangor, Kuala Lumpur and
Putrajaya, the total potential augmentation from treated biomass
efluent is estimated to be 24.5% of total water demands as
shown in Table 5.5.
Large commercial and industrial complexes are known to
have their own recycling systems to meet their own requirements
for non-potable water usage for washroom facilities, cleaning
purposes and landscape work. In some cases, with further
treatment, the water has been used for potable purposes. It is
understood that the irst large scale recycling system is planned
for TRX (Tun Razak Exchange in Kuala Lumpur) with a capacity
of 14 Mld.
► Renewable Energy (RE) Options
Due prominence is now given to usage of renewable sources
Table 5.4: Potential for water supply augmentation by recycling of
wastewater in Selangor, Putrajaya, Kuala Lumpur,
Johor and Penang
2020
Total estimated efluent from Regional Plants (2011)
Total potable water demand in the region
Percentage of water recycled
1151 Mld
8046 Mld
14%
Source: Potable water demand – Review of NWRS (2000-2050Treated Efluent
– MWIG 2012
19
will not only address carbon reduction, but can indirectly
assist in providing alternative options to building dams.
Energy provided by RE is green and clean and with
strong Government participation the mission will receive
encouraging public support. The scheme is in the early
stages of development in Malaysia. Electricity generation
RE by Public Licences by region in 2011 is as shown in
Table 5.6.
► The River Revitalisation Program
The Four River Restoration Project to restore the four major
rivers in South Korea is one of the most recent schemes
implemented to provide water security, lood control,
ecosystem vitablity and small-scale hydropower.
Source: International Water Association (IWA) Water 21 August 2013
Figure 5.4: Milestones in indirect potable water reuse with selected
connected projects
The project sets on exemplary case of strong determination
and accomplishment in recent time in this part of the world
to resolve deiciencies in drinking water and water for
industrial and agricultural uses. The Korean Government
spends US$18.3 billion over 3 years (2009-2012) on the
project. The project also improves the water quality of the
rivers to an average of grade 2. The project scopes and
effects are seen on Table 5. 7.
In Malaysia, the Klang River Rehabilitation Programme is
currently on-going. Perhaps the whole stretch of the river
would be rehabilitated or “cleaned-up” in the future to resolve
deiciencies in domestic and industrial water and also for
environment and renewable beneits.
Summary of Conclusions
Source: International Water Association (IWA) Water 21 – August 2013
Figure 5.5
Table 5.5: Potential for water supply augmentation by recycling of
wastewater in Selangor, KL and Putrajaya
YEAR 2020
Total estimated potable water demand for Selangor,
KL and Putrajaya
4896 Mld
Total estimated efluent water available for recycling
(source IWK estimated)
1200 Mld
Percentage of water recycled
24.5%
Source: Potable water demand – Review of NWRS (2000-2050Treated Efluent –
MWIG 2012
of energy (RE). In the Five-Fuel Diversiication Policy (2001),
RE is incorporated as the ifth fuel, the other four being oil,
hydro, gas and coal (Malaysia Energy Outlook 2010-2030,
EPU.).
Under the Renewable Energy Act 2011, there are only
four technologies applicable for Feed-in Tariff (FiT)
portfolio, which are biomass, biogas, solar photovoltaic
and small hydro. It is reported that the Sustainable Energy
Development Authority Malaysia (Seda) is considering the
inclusion of wind as another renewable resource in the RE
Scheme. Seda together with Energy, Green Technology and
Water Ministry is on a mission to increase RE sources, which
20
It is apparent that there is a future in the provision of RE
and the implementation of green technology as both are
strongly supported by the Government and with public-sector
participation. In both cases, intensive efforts are being undertaken
to provide alternative options to production of energy via RE
and reduction and saving in usage of electricity by application
of green technology.
There is as yet to be an effective effort in all-round reduction
in water usage and consumption in the Water Industry and
production of additional water sources, like recycling of biomass
efluent and rehabilitation of rivers to a scale which constitutes a
sizeable igure in water use and consumption.
Any remarkable success in these areas will no doubt
inluence decisions on dam building of the future.
6.0 CONCLUDING THOUGHTS
On balance, there is still good ground to justify more dam
construction in Malaysia but this must be preceded by in-depth
study and detailed planning at least ive to ten years or even
more before any project is started with most issues of concern
scrutinized and agreed to everybody’s satisfaction and adverse
impacts reduced to absolute minimum. It is important, therefore,
that an Integrated River Basin Management Plan (IRBM) be
completed before implementation of large structures, like dams.
Dams should be made more attractive to the people and
people must be seen to beneit from large projects like dams.
Dams should not only be seen as beneiting from industry’s point
of view but should also address rights of the people especially
those affected by land acquisition and resettlement. This can be
achieved by following an internationally respected standard for
Table 5.6: Electricity Generation (RE) by Public Licences in 2011
Region
Peninsular Malaysia
Sabah
Sarawak
Type of Prime Mover
Installed Capacity (MW)
Unit Generated (MWh)
Land Fill Gas
Mini Hydro
Solar
Palm Oil Mill Efluent (POME)
Subtotal
Palm Shell & Empty Fruit Bunch (EFB)
Wood Waste
Mini Hydro
Palm Oil Waste
Subtotal
Mini Hydro
Solar
Subtotal
2.00
45.98
0.80
2.00
48.78
35.20
10.00
17.34
14.00
76.54
6.00
0.02
6.02
131.3
5,613
38,780
666
2,030
47,089
165,425
4
47,841
69,483
282,753
7,021
15
7,036
336,879
Grand Total
Source: National Energy Balance 2011- Suruhanjaya Tenaga
Table 5.7: The Four-River Restoration Project, South Korea
Project Scope & Effects
Unit Generated (MWh)
Dregging: 450 million m3
Detentions: 5 places
Reinforcing dilapidated leeves: 784km
Movable weirs: 16
Water Security Dams: 2
Elevating agricultural reservoir banks: 96
Water Quality Sewage treatment facilities: 1,281
Improvement Total-phosphorus treatment facilities: 233
Ecological
Ecological wetlands: 118 million m2
Restoration
Fish-ways: 33 sites
Waterfront
Bicycle paths: 1,757km
Development Tourist attraction sites: 36
Lowering lood water levels (2-4m)
Flood Control
Secure 1.3 billion m3 of water
Swimmable water 76% → 86%
Improve natural ecology & promote eco-tourism
Better quality of life
Source: The River Revitalization of Korea
dam design, building and operation, such as the Hydropower
Sustainability Assessment Framework as described in section 4.
Dams need not be the only solution in preparing for the
future in water security but it is a good option when viewed in
terms of risks involved in future global climate change impacts
which is uncertain. What is certain are the observed, abnormal
climate-related events in recent years of increased variability of
rainfall resulting in historic loods and droughts in many places
around the world.
What should a responsible and pro-active government do to
prepare for water resource investment of the future to avoid water
security risks and where could dams play any useful role? This
is a very important and vital area where there need to be close
cooperation between states and between states and the national
government with coordination provided by a mechanism at the
highest federal level.
Addressing
The
Need
For
Future
Dams
Developing countries, like Malaysia, may still need to build
large dams for development in the future (possibly up to 2050)
for the following reasons:
First:
The uncertainty in ‘human-induced’ climate change situation
and consequently extreme climatic conditions may render river
lows in many parts of the country to be unstable and unreliable
at unpredictable time for irrigated agriculture, domestic and
industrial supplies.
Second:
Demand for electrical energy is large and it appears unlikely that
RE can be substantially produced in the future to replace oil,
gas and coal. Nuclear Power is an option which has yet to be
accepted for use.
Third:
Paddy irrigation in granary areas needs a large volume of water
and, at the moment, supply from river sources can be unstable
throughout the year, except regulated by strategic reserves in
dams like the MADA Scheme. Furthermore, with increase in
energy cost, pumped paddy irrigation scheme, like the Kemubu
Agricultural Development Authority (KADA) Scheme, will be
expensive to maintain and operate.
21
Fourth:
Hydroelectric scheme is expected to be promoted because it is
RE, source of clean energy and green.
Fifth:
As the country transforms into a developed nation, the water
management approach will also have to transform in tandem.
This is the change from Supply-side Management to meet the
basic needs of a developing country, to that of Water Demand
Management, a characteristic of a developed Nation that makes
best use of available infrastructure and water. However, it will
still take sometime to achieve a mature and stable environment
to complete that transformation and achieving high levels of
water security is a critical element in this process. Thus for now,
the prudent strategy would be to continue planning for dams as
a component of total water resources management plan for the
future.
Sixth:
Recovery of additional source of water for use as industrial water
or other non-potable uses can be substantial from recycling of
treated biomass efluent. For developed areas in Selangor, Kuala
Lumpur and Putrajaya, for example, there is potential to make
use of this facility up to 25% of their total water demand in
2020. The volume is substantial and is likely to increase in the
future and, therefore, is also worth implementing for economic
reason. However, the will to proceed appears, so far, to be not
so forthcoming.
nothing much has been done for water. It is timely, therefore,
that a national mechanism be set up at the highest level to assist
and coordinate water bodies at federal and state levels in allround reduction in water usage and consumption and production
of additional water sources, like recycling of biomass efluent
and rehabilitation of rivers to a scale which constitutes a sizeable
igure in water use and consumption. At the same time, this
national mechanism could assist in setting up a “Government
Commission on Dams” for enforcement of dam safety in
Malaysia.
ACKNOWLEDGEMENTS
I would like to record my sincere thanks to Ir. Mohd Adnan bin
Mohd Nor, Managing Director, RPM Engineers Sdn Bhd for his
untiring effort in advising and supporting me in the preparation
of this paper. My thanks also goes to Mr. Rory Patield of
Universiti Teknologi Malaysia (UTM) and staff of SMHB Sdn
Bhd. Without their untiring support, the preparation of this paper
would not have been as planned.
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[1]
Bjorn F. Dahlen (1993) Hydro Power in Malaysia. Tenaga
Nasional Berhad (TNB). Published by TNB, Kuala Lumpur.
[2]
Alan C.Twort (1990) Binnie & Partners. A short History to 1990,
Published by Binnie & Partners, Redhill, Surrey, UK.
[3]
Alan C.Twort (1991) Binnie & Partners, 1890 to 1990, (Another
version of the 100-year history). Published by Binnie & Partners,
Redhill, Surrey, UK.
[4]
W.J. Carlyle (1994) Dams in Malaysia. The British Dam Society
Presentation, at the Institution of Civil Engineers (ICE), London.
[5]
Food and Agriculture Organisation of the United Nations (FAO)
(2004). FAO Water Report 27: Economic Valuation of Water
Resources in Agriculture. Retrieved from www.unwater.org/
downloads/wr27e.pdf.
[6]
Irrigation and Agriculture Drainage Division. (BPSP)-(2007).
The History of Irrigation in Malaysia. Irrigation and Agriculture
Drainage Division Ministry of Agriculture and Agro-Based
Industry, Malaysia.
[7]
Aviva Imhof, Susanne Wong and Peter Bosshard 2002: Citizen’s
Guide to the World Commission on Dams, published by
International Rivers Network, Berkeley, USA.
[8]
Proceedings of the International Symposium on Dams in the
Societies of the 21st Century, ICOLD-SPANCOLD, 2006,
Barcelone, Spain, Edited by Spanish National Committee on
Large Dams, SPANCOLD and published by Taylor & Francis/
Balkema, The Netherlands.
[9]
The Royal Academy of Engineering, London, 2010. Global
Water Security – an engineering perspective, published by The
Royal Academy of Engineering www.raeng.org.uk.
Seventh:
Unless there is irm commitment by the Government to invest on
rehabilitation and cleaning the large bodies of water, like rivers
and lakes, to enable large extra volumes of water to the available
for use, strategic storage in dams remains a solution for security
of supply.
Eights:
The Water Industry needs strong leadership at the highest
national level in Water Resources Management to ensure
integrated management at Federal and State levels. Among the
objectives is to possibly change the lifestyle of the people: use
less water, reduce wastage and cut down on losses – a necessary
feature of a developed country status. Unless this is achieved,
the fundamental demand of services the dam provides will not
be reduced.
Finally, with the increase of freshwater scarcity and energy
cost, the strong links between water and energy are becoming
increasingly obvious. The ‘Water-Energy-Nexus’ has become
an increasingly important concept in recent times; it recognizes
that energy and water are intrinsically linked and should be
considered together as opposed to independently. Energy drives
every element of the water cycle, while water is necessary for
energy production. The effects of climate change and global
warming reinforce the need for a holistic approach to the
management of energy and water into an integrated system.
This holistic approach has not effectively taken place, at the
moment, in Malaysia. While a lot of focus has been given to
energy with the creation of government agencies SEDA (for RE)
and GreenTech Malaysia (for green technology/climate change)
22
[10] Tenth Malaysia Plan 2011-2015, published by The Economic
Planning Unit, Prime Minister’s Department, Putrajaya, 2010.
[11] Suruhanjaya Tenaga (Energy Commission), Ministry of Energy,
Green Technology and Water (KeTTHA), National Energy
Balance, 2011, published by the Energy Commission.
[12] Review of the National Water Resources Study (2000-2050) and
Formulation of National Water Resources Policy, Final Report,
2011.
[13] Cecilia Tortajada, Dogan Altinbilek, Asit K. Biswas; 2012,
Impacts of Large Dams ; A Global Assessment, Water Resources
Development and Management ISSN: 1614-810X.
[14] The River Revitalisation of Korea, 2011, The Four Rivers
Restoration Project, Republic of Korea (www.4rivers,go.kr/eng).
[15] Valentina Lazarova, Kwang-Ho Choo, Peter Cornel, 2012,
Water-Energy Interactions in Water Reuse, International Water
Association, published by IWA Publishing, London, UK.
[16] Detailed Environmental Impact Assessment Study (1999) for the
Sg. Selangor Dam in Hulu Selangor.
[17] Ninth Malaysia Plan (2006-2010), the Economic Planning Unit,
Prime Minister’s Department, Putrajaya, 2006.
[18] Water 21, Magazine of the International Water Association
(IWA), valentine Lazarova, Global Milestone in Water reuse,
August 2013.
[19] International Hydropower Association (2013) hydropower
Sustainability
Assessment
Protocol
http://www.
hydrosustainability.org/protocolaspx.
[20] Food and Agricultural Organisation of the United Nations (FAO),
2012, Hot Issues: Water Scarcity. Retrieved from www.fao.org/
nr/water/issues/scarcity.htm/.
[21] Malaysia National Committee on Irrigation and Drainage
(MANCID) 2013. Development of Terms of Reference for
a National Irrigation and Drainage Centre of Excellence and
Irrigation Management Modernization Country Assessment
Report for Malaysia. Final Report, Ministry of Agriculture and
Agtro-ased Industry Malaysia.
[22] Muda Agricultural Development Authority (MADA) 2013.
Retrieved from http://www.mada.gov.my.
[23] The Southern African Development Community (SADC) 2013
Per Capita Water Storage Indicator. Retreived from http://
www.sadc water accounting.org/indicators/4.5 Percapita Water
Storage. asPX.
[24] Department of Irrigation and Drainage (DID) 2013 retrieved from
http://www.water.gov.my
[25] International Rivers, Berkeley CA, USA, February 2012. Three
Gorges Dam, A model of the past. www.internationals.org/en/
node/356.
[26] Water Services Industry Performance Report 2012, Suruhanjaya
Perkhidmatan Air Negara (SPAN).
[27] Malaysia Water Industry Guide, 2012 published by the Malaysian
Water Association (MWA), in collaboration with KeTTHA and
SPAN.
[28] Steve Maxwell, TECHKNOWLEDGE Y. Strategic Group.
The State of the Water Industry, Blood of the Earth – Store of
Economic Value.
[29] Water Markets in Australia, a short history (2011) Australian
Government, National Water Commission.
[30] Asian Development Bank (ADB), Asian-Paciic Water Forum
(APWF), Global Water Partnership (GWP), Stockholm
September 2013, Asian Water Development Outlook – Water
Security Assessment Framework, Ian W. Makin, Principal Water
Resources Specialist, ADB.
23
Control of Bifurcation Behaviour of the Buck Converter via a
Resonant Parametric Perturbation Circuit
Ir. Dr Ng Kok Chiang*1, Dr Michelle Tan Tien Tien2, Dr Nadia Tan Mei Lin3
1
R&D Centre, Leong Hing Sdn. Bhd., No. 1, Jalan P4/7, Seksyen 4, Bandar Teknologi Kajang, 43500 Semenyih, Selangor,
Malaysia. 2The University of Nottingham Malaysia Campus, Jalan Broga, 43500 Semenyih, Selangor, Malaysia.
3
Universiti Tenaga Nasional, Jalan IKRAM-UNITEN, 43000 Kajang, Selangor, Malaysia.
*Corresponding author: [email protected]
ABSTRACT
Nonlinear circuits and systems research has been growing very quickly over the past two decades. Actively pursued in almost every
branch of science and engineering, nonlinear systems theory has found wide applications in a variety of practical engineering
problems. Engineers, scientists and mathematicians have similarly advanced from the passive role of simply analyzing, or
identifying chaos to their present, active involvement in controlling chaos – control directed not only at suppression, but also at
exploiting its enormous potential. We now stand at the threshold of major advances in the control and synchronization of chaos
for new applications across the range of engineering disciplines. All feedback controlled power converters exhibit certain
non-linear phenomena over a speciic breadth of parameter values. Despite being commonly encountered by power electronics
engineers, these non-linear phenomena are by and large not thoroughly understood by engineers. Such phenomena remaining
somewhat mysterious and hardly ever been examined in a formal way. As the discipline of power electronics becomes more
matured, demand for better functionality, dependability and performance of power electronics circuits will inevitably force
researchers to engage themselves in more detailed study and analysis of non-linear phenomena and complex behaviour of
power electronics converters. The bifurcation behaviour of the buck converter occurs when the input voltage is varied. In this
study, the computer simulation scheme, PSPICE is employed to model the behaviour of the ideal buck converter. For certain
values of the input voltage Vin instability occurs. The resonant parametric perturbation method is then applied to control
the bifurcation behaviour of the voltage-mode controlled buck converter. Analysis and simulations are presented to provide
theoretical and practical evidence for the proposed control method. As the buck converter has wide industrial application, it
would be deemed necessary for designers to know about its bifurcation behaviour and how to control such behaviour.
Keywords: Bifurcation, Chaos, Control, Buck Converter, Parametric Perturbation
1.0 INTRODUCTION
Bifurcations control involves the designing of a controller to
curb or lessen the bifurcation dynamics of a given system to
attain desirable dynamical behaviour. There have been proposals
for control methods to bifurcation and chaos behaviour for a
variety of engineering applications [1-3]. The objectives of the
control methods can be divided into two groups. The irst is
the identiication of one of the unstable periodic orbits within
a chaotic attractor as the control target and the utilisation of a
control technique to speciically stabilise the system on the
targeted periodic orbit [2]. The second group involves the control
action to attain the required operating state (target) without much
emphasis on which unstable orbit that is stabilised in the chaotic
attractor. The feedback scheme is used to for the irst category of
control objective, while the non-feedback scheme is employed
mostly for the second category [2, 3].
For the feedback method, some parameters of the control
mechanism are changed to attain the required control objective
after the establishment and implementation of control laws. These
control laws are established from the collection and examinations
of the system variables via experiments and simulations [2, 3].
Among the techniques that are currently employed to counter the
bifurcation behaviour using the feedback method are the deferral
of the incident of an intrinsic bifurcation, the modiication of
24
the shape or nature of the bifurcation, the introduction of a new
bifurcation phenomena, the ine tuning of the system performance
around a bifurcation point, the supervision of the multiplicity,
amplitude and frequency of some limit cycles surfacing from a
bifurcation process, and the adjustment of the parameter sets or
values of an existing bifurcation point [1].
As for the non-feedback scheme, there is no need for any
system variables to be gauged, and it is of no necessity to identify
any speciic periodic orbit as the control target [4, 5]. Among the
known techniques of controlling bifurcation behaviour without
feedback are the resonant parametric perturbation technique
[4-6], the weak periodic perturbation, and the entrainment and
migration control [7, 8]. Contrasting the non-feedback scheme to
the feedback scheme, the method that is more suited for practical
implementation and for anti-jamming ability is that of the nonfeedback scheme [7, 9].
Implementation of bifurcations and chaos control with
speciic objectives have been successful in various experimental
systems and numerical simulations in a wide range of ields and
disciplines, the former including electrical, mechanical, chemical,
and the latter, aeronautical studies, biology, meteorology,
physics and chemistry [10]. Bifurcation control usually paves
the way to the identiication of chaos control as bifurcation is a
generic route to chaos in most nonlinear dynamical systems [1012]. In the course of this study, the non-feedback type of control,
CONTROL OF BIFURCATION BEHAVIOUR OF THE BUCK CONVERTER VIA A RESONANT
PARAMETRIC PERTURBATION CIRCUIT
namely the resonant parametric perturbation method, will be
examined in detail for the control of chaotic and bifurcation
behaviour of the buck converter.
2.0 METHODOLOGY
The PSPICE Model for this study –The PSPICE schematic of
the closed-loop voltage feedback buck converter used in this
study is depicted in Figure 1. The changes made in this PSPICE
circuit however are the replacement of one of the comparators
with a gain of 8.4 in the Fossas and Olivar’s paper with an ideal
multiplier and a difference comparator, which forms the error
ampliier circuit of the buck converter to generate the birfucation
behaviour and the replacement of Vref with the Vref- (1 + α sin 2πf r t )
function as the control which forms the Resonant Parametric
Perturbation Circuit as indicated in Figure 1 [13, 14]. The PWM
controls the ideal switch, S1 and it is the most complex part of the
switched regulator of the buck converter [13, 15]. The switched
buck converter circuit in this study uses a PWM integrator
circuit. The PWM circuit consists of the wave generator, the
error ampliier and an ininite gain comparator. The PWM
controls the ideal switch, S1 and is the most complex part of
the switched regulator of the buck converter [13, 14]. All the
components used in this PSPICE model are ideal components.
Both switches, S1 and S2 have zero on and ininite off resistance,
and can switch instantaneously. Both the S1 and S2 switches
work in a complementary manner. When S1 is on, S2 will be off
and the input voltage supplies energy to the load resistance and
the inductor. On the other hand, when S1 is off and S2 is on, the
inductor current decays while lowing through S2 and at the same
time transfers some of the stored energy to the load resistor.
The output voltage is controlled by setting the frequency of the
sawtooth generator to be of constant switching frequency and by
altering the on-interval of the switch. The switch ratio, d which
can be characterised as the ratio of the on-time to the switching
period is changed through the PWM switching. As the switches
turn off and turn on in a complementary way, instantaneously
allowing the current low in two different directions, the
discontinuous conduction mode can be assumed to be avoided.
Such mechanisms of the switches also cater for the existence of
light load levels [13-15].
In this work, the circuit parameter with the strongest effect
on the system is employed to be the perturbation parameter,
i.e. the reference voltage, Vref of the buck converter circuit. The
circuit used to study the effectiveness of the resonant parametric
perturbation method in controlling the chaos and bifurcation
behaviour of the buck converter will be further discussed in the
Results and Discussion section of this paper. The waveforms
obtained are then observed and analysed to establish the effects
of the changes of the perturbation amplitude, in the newly
introduced function, Vref (1 + α sin 2πf r t ) on the typical circuit
characteristics.
The perturbation frequency fr is set to the driving frequency
and the perturbation amplitude, α is varied from 0 to 0.25. The
chaotic behaviour of the buck converter when Vin = 33 V is
examined in this study. Simulation of the buck converter for each
value of α is presented in three main categories of waveforms
namely, the time-domain voltage and current waveforms, the
Fast Fourier Transform (FFT), and the phase portrait (better
known as the Trajectory).
Procedures in Controlling the Bifurcation Behaviour – The
value for α of the resonant parametric perturbation function
in the PSPICE model of the buck converter
in Figure 1 is varied while other circuit parameters are held
constant to obtain the required waveforms. The ixed value
parameters, which include the input voltage, Vin (when the circuit
exhibits chaotic behaviour), the load resistor, R, the inductor, L,
the capacitor, C, switching frequency, ƒ of the ramp generator,
the perturbation frequency, ƒr , and the ramp upper and lower
voltages are as summarised in the Table 1.
Figure 1: PSPICE Schematic of the Modiied Voltage Feedback Buck Converter with Resonant Parametric Perturbation Control Circuit
25
IR. DR NG KOK CHIANG; DR NADIA TAN MEI LIN; DR MICHELLE TAN TIEN TIEN
Figure 2: Output Voltage at α = 0.00
Table 1: Values of Fixed Circuit Parameters of the Modiied Circuit
of the Buck ConverterCircuit
The perturbation amplitude, α is varied from 0 to 0.25
and the new circuit is simulated at each of the different values
of α. The corresponding voltage and current waveforms, FFT
spectrum, and trajectories (phase portrait diagrams) are shown
in the Results and Discussion section. All cases are described as
is increased from when the circuit started out in the chaotic state
progresses through to period-2, lastly to period-1.
Figure 3: Inductor Current, IL at α = 0.00
Figure 4: FFT Spectrum at α = 0.00
3.0 RESULTS AND DISCUSSION
The resonant parametric perturbation method is highly effective
in controlling chaos and bifurcations in periodically driven
systems. Although this method requires non-zero control power
even when the system has been reduced to its steady state, the
viability of its implementation to control chaos and bifurcations in
various systems is very encouraging [16-18]. Nonetheless, even
though by and large, parametric perturbation can lead to chaotic
behaviour of a system, it can also be used to suppress chaos if
the right frequencies and amplitudes are selected. Thus, a chaotic
system or a system which is in its period-doubling domain can
be converted into a normal period-1 operation through the
perturbation of some parameters at the right frequencies and
amplitude [16, 18].
The parameter that will be selected to be perturbed using
this technique is usually the parameter that has characteristics
such as strong inluence on the system, and can be easily varied.
In the circuit developed in PSPICE for the control of chaos and
bifurcation behaviour of the buck converter, (see Figure 1),
Vref is chosen to be the perturbation parameter. This parameter
is perturbed with the function
where α and ƒr
is the perturbation frequency. This is to ensure the Lyapunov
exponent is kept below zero [16]. Lima & Pettini’s paper in 1990
[4], proves that the largest Lyapunov exponent will approach
zero from positive which leads to the taming of the chaos. The
period-1 operation then appears when the Lyapunov exponent
falls further below zero if the perturbation frequency fr is the set
to be the same as the periodic driving frequency of the circuit [4,
5]. The PSPICE model of the modiied buck converter to which
includes the resonant parametric perturbation circuit is simulated
for the perturbation amplitude, α being varied from 0 to 0.25
in steps of 0.01. The chaotic reduction effect by the resonant
parametric perturbation circuit when Vin = 33 V is examined
here. Crucial information about the output voltage (the capacitor
voltage), the inductor current and Fast Fourier Transform
Spectrum are collected.
26
Figure 5: Trajectory when α = 0.00
Figure 6: Output Voltage, VC at α = 0.01
Figure 8: Broadband FFT Spectrum at α = 0.01
Figure 9: Chaotic Trajectory when α = 0.01
When α = 0.00, the operation of the buck converter is in
the chaotic region where Vin = 33 V. This is very much the
same operation as in the case of chaotic operation of the buck
converter when Vin = 33 V as previously reported [19-21]. This is
because at α = 0.00, the resonant parametric perturbation circuit
remains dormant and does not affect the operation of the buck
converter signiicantly. When α is increased to 0.01 however, we
can see some improvement in the waveforms as compared to that
when α = 0.00. Random, unsymmetrical disjoint and aperiodic
nature that are evident in the waveforms of the output voltage
and the inductor current of the buck converter as in Figure 6 and
7, have improved a little. Nonetheless, as expected, the output
voltage and the inductor current waveforms still do not follow
a speciic form of repetition. Improvement is also evident in the
phase portrait in Figure 9 where the trajectory is less chaotic
when compared to that in Figure 5. As for the Fast Fourier
Transform Spectrum in Figure 8, a continuous and broadband
nature can still be observed suggesting that the buck converter is
still operating in the chaotic region.
having little hiccups in them. The output voltage and the inductor
current waveforms when α = 0.02 are very much the same as
when the buck converter was operating in its period-2 region as
if when Vin = 28 V as previously reported [19, 21]. Hence, by
just changing the฀฀฀, the operation of the buck converter as if Vin
is equal to 28 V (as been reported previously [19-21]) can be
achieved even at Vin = 33 V, which would have been chaotic if it
was not for the resonant parametric perturbation circuit. The Fast
Fourier Transform Spectrum (see Figure 12) is now no longer
continuous and of a broadband nature as before. Moreover, to
strengthen the argument that the buck converter is now operating
in the period-2 region, the trajectory or the phase portrait in
Figure 13 is a two-branch loop of a period-2 attractor.
Figure 13: Period-2 Trajectory when α = 0.02
As α is increased to 0.02, the waveforms of the output
voltage and the inductor current of the buck converter show
great improvement. The unsymmetrical and disjoint waveforms
of the output voltage and inductor current when α is equal to
0.01 are now showing a constant repetition of waveforms despite
27
As α is increased further to 0.04, the output voltage and the
inductor current waveforms show an even better improvement
than before as can be seen in Figures 14 and 15. The waveforms
are experiencing the smoothing effect of the resonant parametric
perturbation circuit. The hiccups become less evident in the
waveforms, and the trajectory now has the shape of a period-1
trajectory except for the little disjoint at the right bottom corner
of the graph (see Figure 17). The Fourier Transform Spectrum
too has narrowband, discontinuous and isolated frequency
harmonics as in Figure 16. Figures 18 to Figure 21 and Figures
22 to 25 show the waveforms as α is changed to 0.06 and 0.08
respectively. As α is increased further and further, the waveforms
of the output voltage and the inductor current show better and
better symmetry and improvement. The graphs have indeed
become smoother and smoother. When α is 0.08, the waveforms
shown are already as good as those of period-1 operation except
for occasional small laws and hiccups.
28
Finally, when α is equal to 0.09, output voltage and the
inductor current waveforms in the time domain both appear to
be very smooth and periodic in nature, demonstrating that the
period-1 stable operation of the buck converter has been achieved.
This observation is further veriied by its Fast Fourier Transform
Spectrum in Figure 28 where narrowband, discontinuous and
isolated frequency harmonics are very obvious. Furthermore, the
very small hiccup in the trajectory of the buck operation when
α= 0.08, is now gone, and the only thing left is a smooth period-1
trajectory signifying that the operation of the buck converter is
in its stable region similar to its operation with Vin = 20V has
been reported elsewhere [19, 20-28]. Here however, the only
difference is that the buck converter is now operating in period-1
region at Vin = 33 V with α = 0.09 for the resonant parametric
perturbation circuit. The input voltage of 33 V and switching
frequency of 2.5 kHz were chosen because the bifurcation
behaviour that was present in an earlier study [29] used the input
voltage 33 V at the switching frequency of 2.5 kHz. This study
attempts to solve the bifurcation problem that was present in
the earlier study [29]. Thus, α= 0.09 is found to be the smallest
effective perturbation amplitude to bring the chaotic operation
of the buck converter circuit back to its period-1 operation. To
conirm that the operation of the buck converter continues in the
stable period-1 region after α= 0.09, simulations when α = 0.10
and α= 0.20 are carried out and as expected, the results obtained
as depicted in Figures 30 to 37 point to operation of the buck
converter in the stable period-1 domain. Thus, results show that
the resonant parametric perturbation circuit functions effectively
in smoothing out the curves and the waveforms of the output
voltage and the inductor current of the buck converter circuit to
bring it back to its period-1 operation in a non-feedback manner.
4.0 CONCLUSION
Power electronics has always been known to exhibit complicated
behaviour, even in very simple circuits. This is due to their
inherent non-linear and time-varying nature. Throughout the
years, it has been experimentally found that a large number of
non-linear systems in power electronics demonstrate ‘strange
behaviour’ which includes subharmonic oscillations, bifurcations
and chaos. But due to the normal reaction of engineers who
wish to avoid such behaviours through some trial-and-error
procedures these phenomena have remained rather puzzling and
rarely examined in a formal manner. However, it is only with
detailed examination and study of these non-linear behaviours
that better controls of these non-linear behaviours can be found
instead of just sticking to traditional trial-and-error methods.
This paper dealt with the modelling and simulation of the
buck converter in PSPICE to simulate its bifurcation behaviour
and to examine a control technique to counter such behaviour.
Being one of the simplest of the DC-to-DC converters, the buck
converter is chosen to be the subject of this study because of
its widespread representation of the circuit to many practical
DC-to-DC converters. Also, due to its extensive applications
in industrial and engineering applications, the knowledge of
the system behaviour in different regions of parameter space
should be crucial, especially in designing the buck converter for
sensitive equipment.
29
As the buck converter is expected to function under a
generous range of input voltage, Vin, additional control may
be essential to control chaos and bifurcations. The resonant
parametric perturbation method has been chosen in this study
as the non-feedback control strategy to counter the chaotic and
bifurcation behaviour of the buck converter when it is operating
in its chaotic region at Vin = 33V. Figures 5, 9, 13, 17, 21, 25,
and 29 are phase portrait diagrams which shows the progression
of the change from chaotic to period-2 and lastly to period-1
operation of the buck converter when α is varied from 0 to
0.09. Thus, the addition of the resonant parametric perturbation
circuit has indeed turned out to be effective in suppressing
the chaotic and bifurcation behaviour of the buck converter,
bringing its operation back to its period-1 state. The resonant
parametric perturbation method is a method easy to apply
when it is compared to those of the feedback types as no prior
knowledge of the system behaviour is required. Besides that,
as evident from the layout of the circuit in Figure 1, resonant
parametric perturbation control allows easy incorporation of the
perturbation circuit with the existing buck converter circuit.
With better understanding of the system’s behaviour under
different operating circumstances, better control strategies can
be developed and furthermore, proitable exploitation of the
non-linear operating region for engineering purposes may also
be possible. There are also a number of papers on the control of
chaos and bifurcation behaviours now being actively published.
Better knowledge of non-linear behaviour of the system has paved
way for such publications. Bifurcation and chaos control via the
resonant parametric perturbation method is now becoming more
and more useful in engineering applications. Examples can be
found in areas such as power network control and stabilisation,
axial low compressors and jet engine control, cardiac alternans
and rhythms control, and stabilisation in tethered satellites and
bearing systems. Successful implementation of this method in
controlling chaos and bifurcation is now not in doubt anymore as
to its effectiveness in a wide range of systems.
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30
D. C. Hamill and D. J. Jefferies, “Subharmonics and Chaos in a
Controlled Switched-mode Power Converter,” IEEE Transactions
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Y. Zhou, C. K. Tse, S. Qiu and F. C. M. Lau, “Applying
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J. H. B. Deane and D. C. Hamill, “Instability, subharmonics and
chaos in power electronics systems,” in IEEE Power Electronics
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J. H. B. Deane and D. C. Hamill, “Instability, subharmonics
and chaos in power electronics systems,” IEEE Transactions on
Power Electronics, vol. 5, no. 3, pp.260-268, 1990.
[10] G. Chen, “Chaos: Control and Anti-Control,” IEEE Circuits and
Systems Society Newsletter, pp. 1-5, March 1998.
[11] P. T. Krein and R. M. Bass, “Types of Instability Encountered in
Simple Power Electronics Circuits: Unboundedness, Chattering,
and Chaos,” in APEC’90, IEEE Applied Power Electronics
Conference Proceedings, pp. 191-194, 1990.
[12] J. H. B., Deane and D. C. Hamill, “Analysis, Simulation and
Experimental Study of Chaos in the Buck Converter,” PESC’90,
IEEE Power Electronics Specialists Conference Record, Vol. II,
pp.491-498, 1990.
[13] E. Fossas and G. Olivar, “Study of chaos in the buck converter,”
IEEE Transactions on Circuits Systems I, vol. 43, pp. 13–25, Jan
1996.
[14] K. Chakrabarty, G. Podder, and S. Banerjee, “Bifurcation
behaviour in buck converter,” IEEE Transactions on Power
Electronics, vol. 11, pp. 439–447, May 1996.
[15] Poddar, Gautam, K. Chakrabarty and S. Banerjee, “Experimental
Control of Chaotic Behavior of a Buck Converter,” IEEE
Transactions on Circuits and Systems I, vol. 43, no. 8, pp. 502504, August 1995.
[16] P. Colet and Y. Braiman, “Control of chaos in multimode solid
state lasers by the use of small periodic perturbations,” Phys.
Rev., E53, pp. 200-206, 1996.
[17] Y. Braiman and I. Goldhirsch, “Taming chaotic dynamics with
weak periodic perturbations,” Phys. Rev. Lett. 66, pp. 2545-2548,
1991.
[18] R. Chacón and J. Díaz Bejarano, “Routes to suppressing chaos
by weak periodic perturbations,” Phys. Rev. Lett. 71, pp. 31033106, 1993.
[19] H. B. J. Deane and D. C. Hamill. “Analysis, simulation and
experimental study of chaos in the buck converter.” IEEE Power
Electronics Specialists Conference, 2. 1990.
[20] K. A. Mirus and J. C. Sprott “Controlling chaos a high dimensional
system with periodic parametric perturbations,” Phys. Lett. A254,
pp. 275-278, 1999.
[21] W. C. Y. Chan and C. K. Tse, “Study of Bifurcations in CurrentProgrammed DC/DC Boost Converters: From Quasi-Periodicity
to Period-Doubling,” IEEE Transactions on Circuits and Systems
I, vol. 44, no. 12, pp. 1129-1142, December 1997.
[22] R. Gavagsaz-Ghoachani, M. Phattanasak, J.-P. Martin, S.
Pierfederici and B. Davat
“Predicting the onset of bifurcation and stability study of a
hybrid current controller for a boost converter,” Mathematics and
Computers in Simulation, vol. 91, pp. 262-273, May 2013.
[23] S. Hebertt, L. Alberto and C. John, “Robust input–output sliding
mode control of the buck converter,” Control Engineering
Practice, vol. 21, pp 671–678, May 2013.
[24] W. Lu, L. Zhou, Q. Luo and J. Wu, “Non-invasive chaos control
of DC–DC converter and its optimization,” International Journal
of Circuit Theory and Applications, vol. 39, pp 159–174, Feb
2011.
[25] E. Meyer, Z. Zhang and Y. Liu, “Digital Charge Balance Controller
to Improve the Loading/Unloading Transient Response of Buck
Converters,” IEEE Transactions on Power Electronics, vol. 27,
pp. 1314 – 1326, March 2012.
[27] K. Karama, J. Pelaez-Restrepo, M. Feki, B. G. M. Robert and A.
El Aroudi, “Improved static and dynamic performances of a two-
cell DC–DC buck converter using a digital dynamic time-delayed
control,” vol 40, pp 395–407, April 2012.
[28] C. K. Tse and M. di Bernardo, “Complex Behavior in Switching
Power Converters,” Proceedings of IEEE, Special Issue on
Application of Nonlinear Dynamics to Electronic and Information
Engineering, vol. 90, no. 5, pp.768-781, May 2002.
[29] K. C. Ng, N. M.L. Tan and M. T. T. Tan, “ Bifurcation of Buck
Converter,” Journal of the Institutions of Engineers, Malaysia,
vol. 75, no. 1, June 2014.
PROFILES
IR. DR NG KOK CHIANG graduated from the University of Western Australia with irst class honours in Bachelor of Engineering in Electrical &
Electronics and Bachelor of Commerce majoring in Accounting, Investment Finance (Derivatives), and Managerial Accounting. He then furthered
his studies to the University of Nottingham, UK and graduated with a PhD in Engineering having worked in the area of renewable energy and
its storage for three and a half years. Ir. Dr Ng Kok Chiang in his course of research and work had liaised with various organisations such as
E.ON (Power and Gas), Lockheed Martin, Jaguar/Land Rover (supercapacitors in automotive industry/electric cars), Battelle (lab management
and commercialisation), Malaysia Rubber Board (energy management, artiicial intelligent, control, and electronics), and MOSTI (Fabrication of
Advanced Supercapacitors). He is currently the Chief Technology Oficer of MyBig Sdn. Bhd. and a Professional Engineer with the R&D Centre
at Leong Hing Sdn. Bhd. involved in research and prototyping projects in collaboration with various Malaysian Government Agencies and research
bodies. Among the prominent solutions founded were the advanced switching mechanism in the Nexcap storage to eficiently capture minuscule
trickle of charges, intelligent control systems incorporating power electronics device, and the advanced Sunopy solar system.
DR NADIA TAN MEI LIN was born in Kuala Lumpur, Malaysia. She received the B.Eng. (Hons.) degree from the University of Shefield,
Shefield, U.K., in 2002, the M.Eng. degree from Universiti Tenaga Nasional, Kajang, Malaysia, in 2007, and the Ph.D. degree from Tokyo
Institute of Technology, Tokyo, Japan, in 2010, all in electrical engineering. Since October 2010, she has been a Senior Lecturer in the Department
of Electrical Power Engineering, Universiti Tenaga Nasional. Her current research interests include power conversion systems and bidirectional
isolated dc–dc converters. Dr. Tan is a Graduate Member of the Institution of Engineers Malaysia (IEM), a Member of the Institution of Engineering
and Technology (IET), and a Member of the Institute of Electrical and Electronics Engineers (IEEE).
DR MICHELLE TAN TIEN TIEN is an Assistant Professor in the Department of Electrical & Electronic Engineering at the University of
Nottingham Malaysia Campus. She received her BEng. degree in Electrical & Electronic Engineering at Swansea University, Wales, UK where
she also completed her PhD on using one dimensional Zinc Oxide nanowires for bio-sensing application. Michelle’s current research focuses on
the synthesis and characterisation of nanomaterials for bio-sensing applications, with emphasis on graphene, metal oxide and graphene/metal oxide
composites. Besides that, her research also focuses on incorporating graphene composites for application in critical and hard environments, such as
aerospace applications, of which is currently funded by the Ministry of Science Technology & Innovation (MOSTI), Malaysia.
31
Characteristics of Optical Silicone Tactile Sensor
Nurul Fathiah Mohamed Rosli1, Muhammad Azmi Ayub2, Roseleena Jaafar3
1
Faculty of Mechanical Engineering, Universiti Teknologi MARA, 40450 Shah Alam, Selangor Malaysia
1
[email protected]
ABSTRACT
The main objective of this research work is to analyze the characteristics of a newly developed optical tactile sensor for
sensing surface hardness. Many optical tactile sensors are bulky in size and lack of dexterity for biomedical applications.
Therefore, this tactile sensor is design relative small in size and lexible for easier insertion in endoscopic surgery application.
The characteristics of the tactile sensor are calibrated with respect to changes in the diameter, area and perimeter of a silicon
tactile sensor subjected to normal forces applied at the point of interaction. A surface exploration computer algorithm to obtain
the sensing information was developed to analyse the characteristic of the optical tactile sensor. The overall image analysis
technique involves the following main stages: image acquisition (capturing of images), processing (thresholding, noise iltering
and boundary detection) and evaluation (force measurement). The measured forces were then compared to the actual forces to
determine the accuracy of the tactile sensor’s characteristics. The results showed that the sensing characteristic with respect to
changes in perimeter of the tactile sensor is more accurate compared to the other sensing characteristics. The outcomes of this
research shows that the functionality of the developed new image analysis computer algorithm coupled with the silicone tactile
sensor is suitable for biomedical applications such as in endoscopic surgery for measurement of tissue softness.
Keywords: Image Processing, Optical Tactile Sensor and WiT. Introduction
Minimal access surgery (MAS), are known as keyhole surgery is
routinely used as the preferred choice for many operations. The
scanning technology with the assistance of a video camera and
several thin instrument give an useful displays visual information
which is “medical imaging” to the surgeon[1]. “Medical imaging”
is the technique of creating images of the interior of a body for
medical analysis. Currently, surgeons also performed manually
using naked eyes or scanning device to analyze characterization
of soft tissue by captured the images [2]. Unfortunately, the
main limitation this technique is the lack of sense of touch on
the surface characteristic information such on the hardness of the
soft tissue. Tactile sensation is important information for surface
sensorization, manipulation and exploration. Because of that,
many researcher concerning in this area.
During recent years, Minimally Invasive Robot-Assisted
surgery, this has become the main choice for surgically reported
in Science Daily. Because of that, this surgery manipulates the
tactile feedback of organs and assesses the condition of tissue.
In other words, the system allows greater precision and better
visualization compared to MAS technique by the combination
of the image processing with the sense of touch. However, it
would be advantageous for the surgeon to have an idea about the
characteristic of the surfaces which are in contact with the tools.
According to, researcher from Nagoya [3], they developed an
optical three-axis tactile sensor capable to recognize the objects
shape and surface condition either its hardness or smoothness
by utilized image processing as their method to obtain the
information of the sensor. Therefore, the use of optical based
tactile sensor for surface characterization is a new approach
in biomedical applications. This new approach provides more
information regarding the surface condition directly by analyzing
the sensing information. The consequence of this technique,
several applications of a sensor is detecting various tumors in
32
patient’s body by through analyzing the softness of the tissues
based on its sensing information such as the change in size,
shape, texture, etc. [4] will be eased to achieved.
The material used in this project for the development of
the miniature tactile sensor element is silicone rubber. Silicone
rubber is a very stable material and has been widely used in many
ields because of its ability to be fabricated by conventional
techniques, its inherent silicone advantages, including excellent
thermal stability, good water characteristics, weather and
chemical resistance[5] and [6].
Several researchers have actively involved and engaged in
developing a better tactile sensor[3], [4] and[7]. Unfortunately
most of the developed tactile sensors are bulky in size and lack
of lexibility for biomedical applications. Hence, there is a need
to explore and develop new generation of tactile sensor that can
perform various tasks in biomedical applications. The developed
tactile sensor in this paper is focus on the application for
endoscopic inspection where sensorization information is need.
In this research, the development of the vision based tactile
sensor is using single wave optical image conduction method
[7]. The tactile sensor which is made of a silicone based material
has been used for measuring normal and shear forces. The inite
element model and its initial behavior of the tactile sensor was
explained in [8],[9] and [10]. In this paper, the characteristics
of the tactile sensor will be further analyzed by using surface
exploration computer algorithm developed in this research
project.
Thus, the outcome of this study is to validate the functionality,
reliability and characteristics of the optical silicone tactile sensor
using the developed surface exploration computer algorithm that
can measure the normal forces to a high accuracy in order to
facilitate and automate the process of surface characterization.
CHARACTERISTICS OF OPTICAL SILICONE TACTILE SENSOR
1.0 ExPERIMENTAL TEST RIG
A test rig was developed to suit the experimental needs and
designed to characterize the silicone tactile sensor which is
having a diameter of 6mm and 90mm long optical iber. The
test rig has both hardware and software components as shown in
Figure 1 and Figure 2. The description of the main experimental
test rig [8]:
1. Initially, calibrated force Fc, was gradually applied and
increased intermittently at the tip of the tactile sensor. The
constant value of the tactile sensor k was obtained based
on the graph of the “Calibrated Forces vs Deformations”
[9]. Then an actual force Fa was applied to the tip of the
tactile sensor. It was recommended the, Fa values were
approximately equal to the Fc values so that the accurately
and reliability of the calibration results could be easily
observed. To measure the Fc and Fa, a digital force meter
was used.
2. For image acquisition, a CCD camera was used to capture an
image inside the tactile sensor. The image data was delivered
to the frame grabber in the PC via 90mm long iber scope
that was connected to PCI bus of the computer. A computer
image processing algorithm was developed to analysis the
image data and performs an image calibration.
3. The image processing algorithm utilizes WiT 8.2 software
to analyze and measure the image data. During the force
measurement process, three main steps of computer algorithm
were performed; image acquisition, image processing and
image recognition. Details of the image analysis will be
explained in the next section. For the measurements of the
experimental forces Fe, three different sensing characteristics
which were changes in diameter, changes in area and
changes in perimeter. The whole process is repeated three
times to show the repeatability of the measurement results
and their average values were obtained[9].
4. Data obtained from both the image processing algorithm (Fe)
and digital force meter were evaluated and compared for the
three sensing characteristics. Then the average percentage of
error was determined. The lowest average percentage error
obtained would be the selected parameter of study.
Figure 1: Experimental test-rig
Figure 2: Schematic diagram for Industrial Fiberscope [8].
2.0 IMAGE PROCESSING ANALYSIS
To perform the image analysis, a surface exploration computer
algorithm was developed to obtain three different sensing
characteristics; changes in diameter, changes in area and
changes in perimeter of the tactile sensor. Data obtained from the
image analysis will relate to the normal force values. The scope
to be highlighted here is the manner in which the machine vision
system is exploited to calibrate the image of the tactile sensor.
The in-process image analysis is the key important aspect of this
test rig. The hardware components constitute of a PC computer,
frame grabber (type of video card) and CCD camera. The optical
iber scope is connected to the CCD camera to acquire the image
of the tactile sensor. The image is captured and stored for further
processing.
A. Image processing algorithm
The image processing algorithm for the tactile sensing analysis
was developed and programmed using Microsoft Visual C/C++
and WiT 8.2 Image Processing software [10]. The WiT8.2 image
processing library consists of built-in operators which provides
a great toolset for image processing [10]. Additional custom
image analysis operators and control system operators were
specially developed via Microsoft Visual C/C++, which created
a dynamic link library so that the corresponding operators
were available in WiT environment. These image operators
were integrated in theWiT 8.2 Igraph of the image analyzed
algorithm to measure the applied forces. A summary of the data
communication process for the image processing algorithm is
shown in Figure 3. The processes are explained as follows:
1. Image acquisition: The image acquisition was performed
when the image data were captured by CCD camera and
transferred to the computer via iber scope.
2. Image processing: Image processing was performed to
enhance the image by using thresholding and noise iltering
approach: In tactile sensor image analysis, the region of
interest was deined as the circle inside the tactile sensor.
Using the threshing and blobing technique, the selected
circle will be analyzed. Blobing is a technique to get the area
of interest. In this research the area of interest is the white
region (all pixels have a value of 255), as seen in Figure 4(a).
All the relevant information such as height, width, pixel size,
angle, coordinate, parameter, and centroid can be extracted
from the blob.
3. Feature Recognition: Feature recognition was accomplished
by boundary detection of the circle: The circle was detected
by grouping the blobs and iltered until relevant blobs for the
33
NURUL FATHIAH MOHAMED ROSLI; MUHAMMAD AZMI AYUB; ROSELEENA JAAFAR
circle were found. All the parameter values to ilter the blobs
were obtained and optimum values for all conditions were
obtained. After getting a satisfactory hole detection result,
the area, perimeter, diameter and centroid of the hole are
computed using the following equation:1. Area:
(6)
(1)
2. Perimeter:
(2)
3. Diameter:
(3)
4. Centroid: The location of X and Y coordinates were
determined by calculating the centroid of the circle from the
relevant blob data. Please refer to Figure 4(b). The accuracy
of the centroid location depends on the technique, control
variable and the noise analysis. By using equations (4)
and (5), the centroid locations from the relevant blobs are
calculated. All the measurements are in pixels unit.
(4)
Figure 3: Surface exploration computer algorithm low chart.
(5)
Figure 4: Image analysis output (a) boundary detection (b) draw
line.
B. Data Acquisition System
The data acquisition system is realized by the design of Image
Processing Algorithm of the optical silicone tactile sensor. To
obtain the information of the sensor, the characteristic of the
images are analyzed and correlated to the Fa-.
4. Calculation of measured force value: The force value has
been calculated by using equation (6). Here, k a constant
value of tactile sensor determined from the previous
calibrated experiment. This k value depends on the sensing
characteristics which are the changes in diameter, area and
perimeter. It is important to deine k in order to enhance
the performance of the tactile sensor algorithm during realtime object manipulation. The user is required to key in the k
value for each sensing characteristics. All the measurements
are in pixels unit. The equation of the measured force value
is as follows. This equation is according to calibration
experiments.
34
C. Conversion Factor
In order to determine the SI units, the pixel measurement has
to be converted to mm (4). It is clear from the zoomed image
shown in Figure 5 that the, 154 pixels have an equivalent value
to 2.051mm in distance.
Figure 5: Zoomed image taken by CCD camera inside the silicone
tactile sensor.
3.
ExPERIMENTAL RESULTS
This chapter present the analysis of data for the overall
performance of the machine vision for the optical tactile
sensor. The performance of the machine vision will be based
on the analysis of results from the image processing techniques,
the analysis of the source of image noise and the analysis of
deformation behaviour.
Three series of the same experiments were done in order to
ensure reliability and accuracy of the results. The results for the
average forces of the changes in diameter, area and perimeter
were presented in Figure 6, Figure 7 and Figure 8 respectively.
The plotted graphs show the correlation between the calibrated
force, Fc, actual force, Fa and experimental force, Fe for the three
sensing characteristics. The graph demonstrates that the initial
value of Fe, inluences the accuracy of the results. As seen, when
force is applied to the tip of the tactile sensor, all data show
signiicant increase in experimental forces, which indicates that
over prolonged time and increased applied force, the value of the
experimental force become stable and reliable.
The limitation in this inding is the range of the Fa, which is
between 0N to 1.5N. For medical applications, it is considered
satisfactory if the force sensitivity is within the range of
0.1N-11N [4]. Forces higher than this range of values are not
effective using this particular type of optical tactile sensor
because the system cannot analyze the deformation image
completely due to the limitation of the view range. This situation
happens because the image for the next displacement is already
out of view. Hence, the image processing is unable to deine the
data for these images. One of the reasons for this to happen is
due to the small size of the tactile sensor used. Therefore, it is
able to capture the full image up to certain amount of delection.
The optical tactile sensor in term concept in design and method
are suitable for applications in the biomedical industries. Figure
9 shows an example of an image which is out of view and cannot
be analyzed. Further works need to be carried out in this research
study to use smaller silicone tactile sensor (suggest:Ø=3mm)
that can inluence the force sensitivity results so that in future,
this sensor is suitable to be used for small internal parts of the
human body such as arteries.
Another concern is that, the accuracy of the tactile sensor
was not able to be determined directly from these plotted graphs.
Hence, an average error value was calculated to derive the
error value using equation (5) and (6). For the error analysis,
the experimental force value, Fe which is the real time value, is
compared to the actual force value, Fa which refers to the value
indicated by the digital force meter. A lower average percentage
error value indicates forces almost to the actual force line, which
Figure 6: Average Forces for Changes in Diameter.
Figure 7: Average Forces for Changes in Area.
Figure 8: Average Forces for Changes in Perimeter.
35
NURUL FATHIAH MOHAMED ROSLI; MUHAMMAD AZMI AYUB; ROSELEENA JAAFAR
(contrasts color), camera light exposure (controls light) and
camera focal distance (adjusts distance) which are not considered
in the experimental set-up. These factors may possibly inluence
the current indings.
Hence, further work needs to be carried out to consider all
these factors which can either be controlled or removed. Thus,
a conclusion can be made that there is immense potential that
this new optical tactile sensor coupled with surface exploration
computer algorithm is able to assist in biomedical applications so
as to replace the current manual characterization of soft tissues
as well as for detecting various tumors based on its sensing
characteristics information.
5.0 ACKNOWLEDGEMENT
Figure 9: Out of view image.
also signiies the image processing algorithm reliability even
when a small force is exerted onto the tactile sensor.
According to the others conference paper show that normal
force calibration that only analysis one parameter for sensing
characteristics there is area [9].Furthermore, it is dificult to obtain
a good result to analyze with only one parameter are consider.
In this inding, three parameters for the sensing characteristics
of the silicone tactile sensor are analyzed in order to obtain the
best parameter. Hence, the best sensing characteristic to select
is the perimeter because its average error value is the lowest
as compared to the other sensing characteristics as tabulated in
Table 1.
The authors gratefully acknowledge the Ministry of Higher
Education Malaysia (MOHE) for the inancial support under the
ERGS fund (project Grant No: 600-RMI/ERGS 5/3 (17/2011),
and the Universiti Teknologi MARA (UiTM) Malaysia.
6.0 REFERENCES
[1]
M. E. Eltaib and J. Hewit, “Tactile sensing technology for
minimal access surgery––a review,” Mechatronics, vol. 13, no.
10, pp. 1163–1177, Dec. 2003.
[2]
C.-K. Chen, H.-T. Wu, H.-J. Chiou, C.-J. Wei, C.-H. Yen, C.-Y.
Chang, and W.-M. Chen, “Differentiating Benign and Malignant
Soft Tissue Masses by Magnetic Resonance Imaging: Role of
Tissue Component Analysis,” Journal of the Chinese Medical
Association : JCMA, vol. 72, no. 4, pp. 194–201, Apr. 2009.
[3]
S. C. Abdullah, J. Wada, M. Ohka, and H. Yussof, “Object
Exploration Algorithm Based on Three-Axis Tactile Data,”
2010 Fourth Asia International Conference on Mathematical/
Analytical Modelling and Computer Simulation, pp. 158–163,
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J. Dargahi, S. Najarian, and B. Liu, “Sensitivity Analysis of a
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Applications in Biomedical Robotics,” Journal of Materials
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J. Liu and S. Wu, “The Research of Interaction Between the
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05, pp. 1839–1841, 2011.
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J. S. Liu, D. L. Li, J. Yu, and Z. W. Zhang, “Study on Durability
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B. Ali, Sukarnur, and M. Azmi, “Development of Experimental
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Bakri Ali, R. Othman, R. Deraman, and M. A. Ayub, “A New
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A. Halim, B. Ali, and M. Azmi, “Normal Force Calibration for
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Table 2: Concrete mix proportion
Percentage of Error, %
Diameter
Area
Perimeter
13.865
21.726
10.113
(5)
(6)
Where,
n: Number of sample
4.
CONCLUSION AND FUTURE WORK
This paper presents the development of an image analysis
algorithm using WiT environment to facilitate and automate
the process of a silicon tactile sensor behavior. Through series
of experiments, it can be concluded that the image processing
analysis is very important to help in getting detailed information
on the hardness, roughness and other physical surface
characteristics. The result shows that the perimeter (one of the
sensing characteristics) is the best parameter since it has a low
percentage error and able to detect small changes of force with
better sensitivity. There are factors such as background lighting
36
[10] A. Halim, M. Azmi, and B. Ali, “Image Analysis For Deformation
Behavior Of Optical Based Silicone Tactile Sensor,” Proceedings
of 2012 IEEE 8th International Colloqium on Signal Processing
and its Application (CSPA), pp. 23–28, 2012.
PROFILES
NURUL FATHIAH MOHAMED ROSLI was born in Kuala Lumpur, Malaysia. She received her Diploma in Electronic Engineering (Computer)
from Sultan Idris Shah Polytechnic, Malaysia in 2008. In 2012, she received a Bachelor of Mechanical Engineering (Manufacturing) (Hons) Degree
from the Universiti Teknologi MARA, Shah Alam, Malaysia. She is currently doing her Master’s Degree on Robotics and Image processing.
E-mail: [email protected].
MUHAMMAD AZMI AYUB is an Associate Professor for Mechatronics at the Faculty of Mechanical Engineering, Universiti Teknologi MARA,
Malaysia. He received his B. degree of Engineering (Mechanical) from UNSW Australia in 1989, and MSc and PhD from Loughborough University,
UK in 1996 and 2004 respectively. He was the Deputy Dean of the faculty from 2004 until 2009. Currently, he is the Head of the Research Center
for Humanoid Robots and Biosensors. His research interests include mechatronics, visual feedback and control of mechanical systems. E-mail:
[email protected].
ROSELEENA JAAFAR obtained her BEng (Hons) in Mechanical Engineering from Brighton Polytechnic, UK in 1993 and MSc in Computer
Integrated Manufacturing from Loughborough University of Technology, UK in 1994. She is currently an Associate Professor at the Faculty of
Mechanical Engineering, UniversitiTeknologi MARA (UiTM), Shah Alam since 2004. She has completed several eScience Projects since 2008 in
the areas of Automation, Mechatronics, Manufacturing Processes and Systems and Ergonomics. E-mail: [email protected].
37
Effect of Polishing Grits, Temperatures and Selected Activators on
Electroless-nickel Deposition on Cast Aluminium Substrates
1, 2
Ajibola O. O, 1Oloruntoba D.T, and 1Adewuyi B.O.
1
Metallurgical and Materials Engineering Dept., Federal University of Technology., Akure, Nigeria
2
Materials and Metallurgical Engineering Dept., Federal University Oye Ekiti, Nigeria
*[email protected]
*corresponding author
ABSTRACT
The state of the surface of a material controls how stable and lasting such material will be under the service condition. Wear
and corrosion take place on the contacting surfaces. For an eficient engineering design, the surface has to be protected by
different method of surface deposition technique such as electroless-nickel (EN) plating. The irmness and the dependability is
built strongly on the morphology of the metallic ilm. This paper aimed to study the effect of grinding grits, types of activator
and plating operation temperatures on the quantity (EN deposition per unit area) and quality (appearance, lustre, adhesion) of
the nickel plating on Al substrate. A number of experiments were performed from which the best of results were used to model
the trend of each individual effect on plating process. Different grades of polishing grits were applied and their effects on the
adhesion, appearance and quantity of EN deposits per unit area on cast aluminium substrates were studied.
Keywords: Cast Aluminium Alloy, Electroless-Nickel Deposition, Selected Activators, Substrate, Surface Polishing, Plating
Temperature
1.0 INTRODUCTION
Many types of aluminium alloys are employed for engineering
purposes where both or either of light weight and/or corrosion
resistance is required [1] such as automotive engines. Among
these vast classes are aluminium-magnesium alloys, being
found useful in automotive engine cylinder, brake and clutch
master cylinder, yet are subject to wear and corrosion. There
is certain number of environment under which aluminium gets
widely corroded and this occurs mostly in strongly acidic or
strongly alkaline solutions though there are speciic exceptions
[2,3,4,5,6]. Since 2010, Ajibola and Jimoh, and Ajibola et al.,
had been involved in understudying the properties, application
and problems of wear and corrosion of cast aluminium alloys
used in brake master cylinders with hydraulic luids (Figure 1
a,b). The reports of such indings are progressively presented
both at local conferences [7,8] and international conferences [9].
The studies by Ajibola et al., [10,11] were performed to assess
the metallurgical properties and wear rates of brake master
cylinder pistons with the view to improving on the wear and
corrosion resistance of the Al alloy substrates in brake luid. Also,
report of studies by Ajibola et al., [10,11] had recommended
the application of surface treatment and deposition of resilient
metallic ilm as solution to alleviating wear and corrosion
problems of this useful machine part immersed in brake oil.
There is variety of techniques of metal coating. These include
processes like hot dipping, electroplating, anodising, electroless
and autocatalytic deposition [12–13], cladding, parkerizing and
galvanising [14, 15, 16]. Plating has been practiced for many
years, but it is also very signiicant for modern technological
practices. Metallic coating is utilized for decoration, corrosion
inhibition, to improve solderability, to enhance hardness, to
38
increase wear resistance, to lessen friction, to improve paint
adhesion, to alter conductivity, for radiation shielding, and for
other purposes. Metal plating usually fail only in small sections,
and if the plating is more noble than the substrate (for example,
chromium on steel), a galvanic couple will cause any exposed
area to corrode much more rapidly than an uncoated surface
would.
Figure 1: Surface of corroded hydraulic brake pistons samples after
long immersion in brake oil.
Electroless-nickel (EN) deposition is a chemical autocatalytic reduction procedure which is principled on the
reduction of nickel ions in an aqueous solution (containing
a chemical reducing agent) and the subsequent deposition of
nickel metal without the application of electricity. Agarwala and
Agarwala, [17] presented the most widely accepted mechanism
by the following Equations 1-4:
(H2PO2)- + (H2O) Catalyst = H+ + (HPO3)-2 +2Habs
(1)
Heat
Ni2 + 2Habs = Ni + 2H+
(2)
(H2PO2)- + Habs = H2O + OH- + P
(3)
(H2PO2)- + H2O = H++ (HPO3)2- + H2
(4)
EFFECT OF POLISHING GRITS, TEMPERATURES AND SELECTED ACTIVATORS ON
ELECTROLESS-NICKEL DEPOSITION ON CAST ALUMINIUM SUBSTRATES
In the presence of a catalytic surface and suficient energy,
hypophosphite ions are oxidized to orthophosphite. Acid
solutions were found to have several advantages over alkaline
solutions: higher plating rate, better stability, greater ease of
control, and improved deposit corrosion resistance. Using a
proper surface pre-treatment order and precise process control,
high-quality adhesion and outstanding service performance,
very homogeneous thickness is produced all over the part, even
for asymmetrical shapes, holes, recesses, internal surfaces and
valves.
High-quality adhesion of EN deposits on Al alloy emanates
from excellent cleaning and lowest amount etching operations.
There is now a better understanding of the features inluencing
adhesion properties. Good adhesion is reliant on having a
dirt-free surface free from soils, oxides, particulate matter and
embedded materials. For instance, gentle etch alkaline cleaners
work well for many surface contaminating soils.
There are different surfactants such as applicable in cleaning,
surface modiication, sensitization, catalyzing, activation
(acceleration) and as stabilizers. Surfactants are also used as
wetting agents that lower the surface tension of a liquid, allowing
easier distribution, and lower the interfacial tension between two
liquids or a liquid and solid surface. In an EN bath, existences of
surfactants encourage the deposition reaction between the bath
solution and the immersed substrate surface [18]. The deposition
of Electroless-Ni on cast aluminium was investigated for its
wear and corrosion properties through experimental methods
and is reported in this paper.
2.0 MATERIALS AND METHOD
Model, and Brinell hardness tester respectively. The results are
presented in Table 1.
2.2 Preparation of cast samples used for EN
plating
2000g of as-received aluminium alloy sourced from purchased
piston (calliper) was weighed into a melting pot and melted at
temperature range of 750oC to 800oC in electric furnace under a
controlled atmosphere. The molten metal was sand cast into rods
of 300mm long by 30mm diameter from which the two set of
tests specimen (pistons and coins) were cut and machined out.
They were sliced to obtain 15mm thick by 25mm diameter
coin size used for plating tests (Figure 2). The surfaces of the
aluminium alloy substrates were grinded and polished with
different types of polishing grits on the grinding and polishing
machines (Metaserv 2000 model). The microstructure and
surfaces of the samples were examined under the metallurgical
microscope of X800 maximum magniication (Nikon Eclipse
ME600 model).
Figure 2: Pieces of Al alloy specimens for EN plating test.
The commercial aluminium alloy sample was sourced from
the hydraulic brake master cylinder loating pistons (callipers).
The piston (designated as ‘As-received Al alloy’ or ‘AR’) was
procured from automobile spare part market in Ado Ekiti, Nigeria
from which cast rod (designated as ‘Cast Al alloy’ or ‘AC’)
was produced. Aqueous solutions of different chemicals such
as Emulsiier, Sodium hydroxide, Hydrochloric acid, Sodium
phosphate, Zinc oxide, Potassium sodium tartrate, Sodium
nitrate, and Ferric chloride used in pre-treating the aluminium
samples, and EN plating chemical including Palladium chloride,
Nickel Chloride, Sodium Hypophosphite, Sodium citrate,
Ammonium chloride, anti-tarnish chemical (potassium-dichromate solution) were procured from scientiic chemical stores
in Ado Ekiti, Nigeria. The equipments used for the experiment
include: Electronic digital weight meter (model DT-502A,
0.0001g), lathe machine, drilling machine, electrical cutting saw,
electroless Nickel plating line (Figure 3), and thermometer.
2.2.1 Cleaning of samples, surface activation and EN
plating
Table 2 shows the EN pre-treatment and plating chemicals,
media concentrations, operating temperatures and the immersion
periods. The polished samples are cleaned in a series of chemicals
such as bases and acids to prepare the surface for good adhesion.
Each of the chemical pre-treatment is followed by water rinsing
to remove the chemical that adheres to the surface. Degreasing
removes soil and oil, while acid cleaning removes scaling. The
surface activation is done in six different types of solutions:
sodium-di-chromate, palladium chloride solution at 85°C,
zincate, water, HCl and NaOH solution before they are inally
plated with electroless nickel. The surface activation is done in
six different types of solutions before they are inally plated with
electroless nickel.
Pre-cleaned and surface activated samples are immersed
into the electroless-nickel baths operated at varying temperatures
2.1 Chemical analyses of Aluminium alloy
comprising of nickel chloride (source of nickel), sodium
substrates
hypophosphite (reducing agent) and sodium citrate (stabilizer).
The chemical compositions and hardness of aluminium alloy The pH of the EN bath was ixed by adding required quantity
substrates (as-received Al and cast Al) were determined using of ammonium solution or sodium hydroxide solution. After
Atomic Absorption Spectrometer (AAS) Thermo series 2000 the coating process, coated material is immersed in anti-tarnish
chemical to prevent unwanted stains. The EN coated samples
are washed in distilled water
Table 1: Chemical composition and hardness of aluminium alloy substrates.
after, and dried in the oven
Samples
Al
Si
Mg Fe Mn Cu Zn
Cr
Ti BHN after which the quantity of
deposition per unit area is
As-received Al.
98.87 0.38 0.40 0.23 0.001 0.01 0.001 0.001 0.001 43.6
determined.
Cast Aluminium alloy coins
98.44 0.32 0.29 0.16 0.001 0.01 0.001 0.001 0.001 63.8
39
AJIBOLA O. O, OLORUNTOBA D.T, AND ADEWUYI B.O.
Table 2: Plating chemicals and the mixing ratio
Bath
Media
Concentration Temperature
(g/l or ml/l)
(oC)
Emulsiier:
15 ml/l
Kerosene
Emulsifying
with Detergent
15 g/l
solution
Alkaline
Sodium
0.4 g/l
cleaning
hydroxide
Acid
Hydrochloric
5 ml/l
cleaning
acid
Surfactant PCl2
0.0 ~ 0.12 g/l
Plating
Nickel Chloride
30 g/l
Sodium
40 g/l
Hypophosphite
Sodium citrate
25 g/l
Ammonium
50 g/l
chloride
PCl2
0.02/l
60±5
1-5
60±5
1-5
60±5
1-5
85
85±5
0.5-2
2 - 10
The effect of surface inishing on the EN plating was
studied using different emery paper polishing grits (60µm,
120µm, 220µm, 320µm, 400µm, 600µm, 800µm and 1200µm).
In another case, the effects of six selected chemical media
used as surfactants (sodium-di-chromate, palladium chloride,
zincate, water, HCl and NaOH) were also studied. The
inluence of plating bath temperatures varied from 80oC, 85oC
and 90oC temperatures were also examined on the EN plating
characteristics.
The amount of EN deposit (g) is determined from the
difference between the initial weight (Mi) and inal weight
(Mf), measured before and after EN plating using electronic
digital weight meter, from which the amount deposited per unit
area (g/mm2) and EN plating rate (g/mm2/min) are calculated;
∆W = Mf – Mi
(5)
Amount EN deposited per unit area = ∆W/(AT)
(6)
EN deposition rate REN = ∆W/(AT x t)
(7)
where Wi = weight of the sample before EN-plating, Wf =
weight of the sample after EN-plating and ∆W = EN ilm
weight deposited, AT = Total surface area of substrate, t =
plating time.
Figure 3: Pictorial views of complete assembly of the cleaning line
(a) and EN plating bath (b).
3.0 RESULTS AND DISCUSSIONS
3.1 Characteristics of the aluminium substrates
The aluminium alloy substrates, (as-received Al or AR and cast
Al or AC samples) were characterised by atomic absorption
spectrometry to ascertain the chemical composition of the
40
Time
(mins)
substrates. The micro-structural examination is
carried out to reveal the micro structure of the alloy
and to compare the similarities and differences.
The hardness values are compared as means of
predicting their behaviour under friction with respect
to their composition and micro-structure. With these,
some reasons for their corrosion and wear behaviours
of the aluminium alloy substrates could be understood.
Table 1 shows the results of chemical compositions
and hardness of as-received Al alloy (control sample)
and cast Al alloy used in the experiment. The chemical
analysis shows that 98.87%Al, 0.38%Si, 0.40%Mg,
and 0.23%Fe were present in the AR, that 98.44%Al,
0.32%Si, 0.29%Mg, and 0.16%Fe were present in
the AC while equal amount of 0.001%Mn, 0.01%Cu,
0.001%Zn, 0.001%Cr and 0.001%Ti were present in
both AR and AC alloys.
3.2
EN deposition per unit area on
aluminium substrates
The trends and amount of electroless-nickel deposition
per unit area on AR and AC alloy substrates at various
polishing grits, temperatures and surface activation are illustrated
in Figures 4-23.
3.3 Effect of surface polishing grits SFG
variation on amount of EN deposition on AR
and AC at 85oC using PdCl2
Deposition of electroless-nickel on as-received and cast
aluminium alloy substrates at various polishing grit is carried
out for 10 minutes at 85oC.
Figure 4: Effect of SFG variation on EN deposition per unit area
(g/mm2) on AR and AC samples operated at 85oC plating
temperature.
Figure 4 shows that there is more of EN deposition per unit
area on the 60µm and 120µm grits polished as-received alloy
than the cast aluminium substrate. There is steady increase in
the quantity of EN deposition per unit area on cast aluminium
substrate as the grade of surface polishing grits increased from
60µm to 600µm, above which there was reduction in the amount
of EN deposition per unit area obtained on the cast aluminium
substrate. There is subsequent greater amount of EN deposition
per unit area on cast substrate than the as-received substrate with
respect to the increase in the grade of surface polishing grits
used.
It is observed that there is fall in the quantity of EN deposition
per unit area on as-received alloy as grade of surface polishing
grits increased from 60µm to 220µm, above which there was
increase in the amount of EN deposition per unit area obtained
on the as-received aluminium substrate. 600µm surface polishing
grits produced the highest quantity of EN deposition per unit
area on both the cast and as-received aluminium substrates.
The trend of the amount of EN deposited with respect to
increasing polishing grit was studied using the experimental data
generated from the experiment. The best it models for the trend
using MS excel application were of polynomial equations to
power 2 relating the amount of EN deposited to surface polishing
grits (um). The developed models from the study are:
Mn1= -8E-06x2 + 8E-05x + 0.0002
(8)
Mn2= -3E-06x2 + 2E-05x + 0.0003
(9)
where 60≥x≥1200µm, x = grade of surface polishing grits,
Mn1 and Mn2 are the amount (g/mm2) of EN deposited with respect
to surface polishing grits on cast and as-received aluminium alloy
respectively in acidic sodium hypophosphite reduced bath. The
EN deposition per unit area increased with increasing SFG from
60µm to 600µm after which there is reduction in the amount of
EN deposition per unit area on AC Al alloy substrate. The case is
dissimilar in the AR Al alloy, there is decline in the EN deposition
per unit area on 60µm to 220µm grits polished samples; there is
boost in EN deposition per unit area from 220µm to 600µm after
which there is decrease in EN deposition per unit area obtained.
0.000446g/mm2 and 0.000364g/mm2 maximum EN plating per
unit area were obtained on the 600µm grit polished cast and asreceived aluminium samples respectively.
Rough surfaces have more points and crevices than the
smooth surfaces, hence rough surface are likely to have larger
surface areas. Unlike electro-deposition processes (electroplating,
electroforming, etc). Where deposition concentrate more at
points and less at crevices, electroless plating give a more
uniform plating thickness that electro-deposition process, hence
the electroless plating is not solely controlled by the degree of
roughness of surface.
3.4 Effect of SPG and temperature variation on
amount of EN deposition AR and AC at 85oC
using PdCl2
Figures 5-12 show the variation in the quantity of EN deposit
(g) on cast and as-received aluminium alloy substrates in acidic
sodium hypophosphite reduced bath at varying plating bath
temperatures and surface polishing grits. The temperature is
varied from 80, 85 and 90oC while the surface polishing grits
varied from 60 to 1200µm.
produced least quantity of EN deposition per unit area at 80oC
followed by 85oC and 90oC. The 90oC plating temperature
produced highest values of EN deposition per unit area on 220,
320, 400, 600 and 1200µm grit polished surfaces. Similar trends
in quantity of EN deposition per unit area are obtained on 400
to 1200µm grit polished surfaces for 85oC and 90oC plating
temperature operated baths. In principle, electroless deposition
is energy driven. It is a chemical reaction process that is highly
controlled by temperature and time. The kinetics of the reaction
is more favoured and result oriented at higher temperature. In
case of EN deposition, working at temperatures above 80oC had
been encouraged.
The amount of EN deposition per unit area (g/mm2) in
Figures 6-11 are derived from Figure 5. The effect of SFG and
Temperature variations on amount of EN deposition per unit
area (g/mm2) on AC and AR samples with the errors bars are
illustrated in Figure 6-11. All the plots in Figures 6-11 show the
amount of EN deposition per unit area (g/mm2) on cast Al alloy
and as-received Al alloy substrates measured from 8 different
SFG values. The error bars for each plot give the upper and
lower limit (maximum and minimum amount) of EN deposition
per unit area obtained from each of SPG values. For the cast and
as-received substrate samples, the 48 points are within the 5%
the error bars for EN deposition per unit area of the SPG points.
The polynomial trendlines equations (10) to (15) are also derived
from the plots.
Figure 6: Trend of EN deposition per unit area on AC samples on
operated at 80oC plating temperatures with SFG variation with the
errors bars.
errors bars.
Figure 5: Effect of SFG variation on amount (g) of EN deposition
per unit area on AC and AR samples operated at different plating
temperatures (oC).
In Figure 5, 60µm polishing of cast aluminium produced
highest EN deposition per unit area at 80oC followed by 85oC
and 90oC while on other polished surfaces grits from 120µm
to 1200µm, highest values of EN deposition per unit area are
obtained at 90oC. The result obtained at 85oC shows that there
is decline in quantity of EN deposit on 60µm to 220µm polished
Al substrate. The 60µm polishing on as-received aluminium
errors bars.
41
Figures 6-8 are derived from Figure 5. Comparisons of
results of EN deposition on cast samples at different temperatures
in Figures 5, 6, 7 and 8; show that EN deposition per unit area on
AR and AC are of close trend and values in each of the plating
temperatures (80oC and 85oC). Hence, the deposition is more
dependent on the degree of polished surface grits rather than
the aluminium material type; while further observation shows
that for 90oC plating temperature, the deposition is dependent
on both polished surface grits and the aluminium material
types. The trend of the amount of EN deposited per unit area
with respect to increasing plating bath temperature was studied
using the experimental data generated from the experiment. The
polynomial it equations for the trend using MS excel application
relates the amount of EN deposited to plating bath temperature
(oC) and surface polishing grits operated at 80oC, 85oC and 90oC
respectively as:
Mn3 = 5E-06x2 - 4E-05x + 0.0004
(10)
Mn4 = 2E-06x2 - 1E-05x + 0.0003
(11)
Mn5 = 1E-06x2 + 1E-06x + 0.0003
(12)
Where 60≥x≥1200µm, x = surface polishing grits, Mn3,
Mn4 and Mn5 are the amount of EN deposited per unit area
(g/mm2) with respect to plating bath temperatures operated at
80oC, 85oC and 90oC, respectively on cast aluminium alloy in
acidic sodium hypophosphite reduced bath.
Figure 9: Trend of EN deposition per unit area on AR samples on
operated at 80 oC plating temperatures with SFG variation with the
errors bars.
Figures 9-11 are also derived from Figure 5. The trend of the
amount of EN deposited per unit area with respect to increasing
plating bath temperature was studied using the experimental data
generated from the experiment. The polynomial it equations for
the trend using MS excel application relates the amount of EN
deposited on as-received Al alloy (AR) substrates to plating bath
temperature (oC) and surface polishing grits operated at 80oC,
85oC and 90oC respectively as:
Mn6 = 4E-06x2 - 3E-05x + 0.0004
(13)
Mn7 = 6E-07x2 + 5E-06x + 0.0003
(14)
Mn8 = 3E-06x2 - 3E-05x + 0.0004
(15)
Where 60≥x≥1200µm, x = surface polishing grits (µm),
Mn6, Mn7 and Mn8 are the amount of EN deposited per unit area
(g/mm2) with respect to plating bath temperatures operated at
80oC, 85oC and 90oC, respectively on as-received aluminium
alloy in acidic sodium hypophosphite reduced bath.
From Figures 5-11, EN deposition on AR and AC is not
solely dependent on the increase in level of the polishing grit.
The least trend of deposition per unit area is obtained at 85oC,
producing best of the adhesion and appearance at SFG of 600µm
and above. The trend of EN deposition per unit area at all plating
temperatures is observed to be controlled by the increasing
plating temperature especially for 400 to 1200µm polished
surfaces grits. Figure 12 show the appearance of EN plating on
cast aluminium substrate at (a) 80oC, (b) 85oC and (c) 90oC using
1200µm polishing grit.
Figure 12: Micrograph of EN plating on cast aluminium substrate at
(a) 80oC, (b) 85oC and (c) 90oC using 1200µm polishing grit.
3.5. Effect of surface activation on amount of EN
deposition per unit area of Al substrate.
errors bars.
Deposition requires one or more of the following steps such
as (i) cleaning, (ii) surface modiication, (iii) sensitization, (iv)
catalyzing or catalyzing, and activation (acceleration)[19].
Rinsing is required between the steps. The steps (iii) and (iv) as
sensitization and catalyzing. In this work, the selected surface
activators used include HCl, NaOH, water, sodium-di-chromate,
zincate, and palladium chloride solution, before the cast substrates
are immersed into the EN plating baths. Figures 13-16 show the
variation in the quantity of EN deposit on cast aluminium alloy
substrates in acidic sodium hypophosphite reduced bath using
six different reagents as the surface activators.
operated at 90 oC plating temperatures with SFG variation with the
errors bars.
Figure 13: Effect of activators on EN deposition (g) on 1200µm
polished AC samples operated at 85oC temperatures (oC).
42
Figure 14: Effect of activators on EN deposition per unit area
((g/mm2) on 1200µm polished AC samples operated at 85oC
temperatures (oC).
Figure 16: Effect of activators and SFG variations on EN deposition
per unit area (g/mm2) on AC samples operated at 85oC temperatures
(oC).
The Figure 14 is derived from Figure 13. Figures 13 and 14
illustrate the effects of 6 activators and SFG variations on EN
deposition (g) and EN deposition per unit area ((g/mm2) on
1200µm polished AC samples operated at 85oC temperatures
(oC). The effects of 2 activators (zincate and chloride) and SFG
variations on EN deposition per unit area (g/mm2) on 6 different
grits polished AC samples operated at 85oC temperature (oC) are
presented in Figure 15 and 16. The quantities of EN deposit with
respect to activators decline in order of the chromate, palladium
chloride, zincate, water, NaOH and HCl.
The zincate produced relative higher values of EN
depositions than the Chlorides on six of the eight grits tested.
Among the six activators presented in Figures 13-16, only the
zincate and chloride yielded quality EN deposition that could
possibly be of practical beneit.
Deposition of electroless-nickel on AC and AR alloy
substrates at various polishing grits is carried out for 10 minutes
in EN baths operated at 85oC. Figure 17 shows the appearances
of EN deposition on (a) 60µm (b) 320µm (c) 600µm (d) 800µm
(e) 1200µm polished cast substrates (AC) in acidic sodium
hypophosphite reduced bath without use of activators.
Figure 15: Trends of EN deposition per unit area (g/mm2) on zincate
and PdCl2 activated AC samples operated at 85oC temperatures (oC)
with SFG variations.
Comparing the two activators in Figure 15, the patterns of
trend lines generated from the plots are not similar; zincate is
parabolic while PdCl2 is linear (because the integer of x2 is zero);
though the amount of EN deposited per unit area (g/mm2) on cast
aluminium sample increased with SFG using the zincate as well
as the chloride.
The trends of the amount of EN deposited per unit area with
respect to decreasing SFG were studied using the experimental
data generated from the experiment. The polynomial it equations
for the trend using MS excel application relates the amount of
EN deposited per unit area to types of activators (PdCl2, zincate)
used and the surface polishing grits for baths operated at 85oC as:
Mn9 = 7E-06x + 0.0003
(16)
Mn10 = -1E-05x2 + 0.0001x + 0.0002
(17)
where 60 ≥x≥1200µm, x = surface polishing grits, Mn9
and Mn10 are the amount of EN deposited per unit area (g/mm2)
on cast aluminium alloy using PdCl2 and zincate as activators
respectively, in acidic sodium hypophosphite reduced bath
operated at 85oC.
In Figure 16, the use PdCl2 have much signiicant difference
on the amount of EN deposition per unit area on the 600µm
and 800µm grits polished surfaces as the SFG increased from
60 to 1200 µm. The application of zincate gave EN deposition
increased with the increasing SFG values from 60 to 600 µm after
which there is reduction in the EN deposition as SFG increased
from 600 to 1200 µm.
Figure 17: Micrograph of appearances (x50 mag) of (a) 60µm, (b)
320µm, (c) 600µm, (d) 800µm, and (e) 1200µm polished EN coated
cast substrates.
Figures 18-20 show the variation in the quality (appearances,
texture, brightness) of EN deposit on cast aluminium alloy
substrates in acidic sodium hypophosphite reduced bath using
different surface activators.
3.5.1 Effects of H2O, NaOH etched and HCl etched
activation on EN deposition
By water rinsing immediately after the catalytic process (prior to
immersion in the metallizing bath), the amount of oxide material
(Al2O3) present on the surface makes it dificult to obtain reliable
EN deposition. In addition, at that stage the ultra thin supporting
substrate and the deposit are virtually non-conductors.
Etching in HCl acid media stages are oxidation and hydrogen
evolution controlled, while in the case of etching in NaOH
alkaline media the following Metal deposition and Hydrogen
evolution stages are prevailing, thus the deposition reaction can
be considered to be the combined result of two independent
electrode reaction as cathodic partial reactions and anodic partial
reaction.
The activation (acceleration) step involves the removal of
the layer formed by the stabilizing agent with chemicals such as
HCl or NaOH. Thus more EN deposits were obtained from HCl
43
or NaOH etched Al substrates than in water rinsed surfaces. In
some cases the activation (acceleration) step can be omitted, but
then the plating solution may get contaminated [25].
It was observed that HCl, NaOH and water activated cast
below 400µm) under microscopic examination are more prone
to high porosity than the EN coated as-received substrates. It is
observed that the quantity of EN deposition per area is dependent
on the type and roughness of the surface of the aluminium alloy
substrates, whereas the adhesion and brightness are not solely
controlled by the surface polishing grits. There are instances
where low polishing grit produced better and more tenacious
coating than the higher polishing grit.
3.5.3
(a) Metallic, bright EN deposition (x50 mag). (b) mixed, bright and
dull EN deposition (x80 mag)
Figure 18: Micrograph of EN plating on (a) NaOH etched as-cast Al
and (b) HCl etched 1200µm polished cast Al substrates at 10 minutes
plating time.
aluminium alloy substrates did not yield much substantive
quantity and quality EN deposit as compared with sodiumdi-chromate, zincate, and palladium chloride activated cast
aluminium alloy substrates immersed into acidic sodium
hypophosphite reduced EN bath.
3.5.2 Effect of PdCl2 activation and temperatures on EN
deposition
A number of compounds, referred to as stabilizers, exist which
can render an electroless deposition bath stable or at the least
retard precipitation e.g PdCl2. In the present work, the used of
PdCl2 as surfactant, serves as both a catalyst (in the pre-treatment
line) and as a stabiliser in the EN plating bath. Hence, a more
balance trend of EN deposition was obtained from the used of
PdCl2 than what was obtainable in the zincate (Figure 15) when
compared.
Heavy metal cations such as Pb, alter the activity of the
catalytic substrate – hence their marked inluence at even low
concentrations [25]. In principle, an oversimpliied model
assumes that the sensitizing ion can reduce the active metal from
the catalyst solution of a more noble metal (Au, Pt, Rh, Os, and
Ag solutions) and such as PdCl2 in the EN process for example
(18),
Pd2+ + Ni2+ = Ni4+ + Pd0.
(18)
Figure 19 shows the Micrograph of EN plating on (a-d) 60µm
cast Aluminium substrate at different temperatures. Observations
show that EN plated cast aluminium alloy substrates (polished
(a) PdCl2 activated EN chips at 85oC (x100 mag), (b) PdCl2 activated
dull EN lakes at 90oC (x100 mag), (c) Dull EN deposition at 85oC
(x50 mag), (d) Bright EN deposition at 90oC (x50 mag),
Figure 19: Micrograph of EN plating on (a-d) PdCl2 activated 60µm
grit polished cast aluminium substrate at different temperatures.
44
Effect of zincate activation on EN
deposition
Zincating is more or less a metalised type of surface activation
or catalysing process for Al alloy, using a basic solution which
consisted of sodium hydroxide and zinc oxide, and at times
contains iron, a zincate ilm formed by single zincate treatment
Most of the Ni-P baths are acidic, Ni is more electro-positive
than Al on the electromotive scale, immersion deposits of nickel
and chemical attack of the aluminium substrate will occur,
interfering with the good adhesion of the electroless nickel
coating. In protecting the Al substrate during EN plating process,
zinc immersion deposits are used. The zinc deposit protects
aluminium surface against re-oxidation from atmosphere and
re-dissolves in the EN solution, hence forming adherent EN
coatings on an exposed oxide free aluminium substrate.
(a) Uniform deposition, (b) Lumpy, bright and dull deposition at
90oC (x80 mag), (c) Sparingly coated (x50 mag). (d) Fine, bright and
dull deposition at 85oC (x50 mag),
Figure 20: Micrographs of EN plating on (a) 60µm zincated surface
(b) 120µm zincated substrate, (c) 120µm polished cast substrate and
(d) 1200µm cast substrate.
Figure 21 shows the appearances of the PdCl2 (Figure 21b) and
zincate (Figure 21c) activated EN plated cast aluminium pistons
obtained from 600µm polishing grit. The depositions were
uniform, continuous, of very bright metallic lustre with good
adhesion.
Figure 21: (a-c) surfaces showing (b)PDCl2 and (c) zincate activated
EN plated cast aluminium samples
Calculating the plating rates based on data generated from
Figures 14 using equation (7); lower plating rates of 0.00849
mg/mm2/min, 0.00886 mg/mm2/min and 0.0169 mg/mm2/min
were obtained from using HCl, NaOH and water as cleaning
reagents. Pure and aluminium alloy form layer of oxide when
exposed to air and water. This oxide reduces the adhesion of EN
on the surface. The oxide is reactive to both acid and alkaline;
hence they disallow the continuity of autocatalytic reaction at the
immediate interface of the EN solution and the substrate.
Higher plating rates of 0.0301 mg/mm2/min, 0.0241 mg/
mm2/min and 0.0290 mg/mm2/min were obtained from cleaning
with chromate, zincate and chloride. The highest plating rate is
obtained from chromate cleaned substrate but of worst adhesion
quality among the three. Zincate and chloride cleaned aluminium
substrates yielded better quality than chromate cleaned cast
aluminium substrate. The application of zincates as primer on
cast aluminium substrate before EN-deposition has been widely
accepted, reported to be result oriented and encouraged for better
adhesion. [20, 21, 22, 23, 24].
Adhesion problem is one of the major experienced challenges
of EN plating especially when the substrate is aluminium
alloy. The cast aluminium alloy has greater challenges of EN
plating than other wrought aluminium materials hence cast Al
surfaces are specially prepared by cleaning in diverse reagents
and followed by surface activation. 17-20 show the variation in
the quality of EN deposit on cast aluminium alloy substrates in
acidic sodium hypophosphite reduced bath using six different
reagents as the surface activators. The best yield in terms of
the plating quality (adhesion and appearance) is obtained form
the activation in palladium chloride solutions (Figure 19) and
in zincate (Figure 20), though gotten in Figure 12 are of lower
quality yields as compared with what was obtainable in zincate
pre-treated cast aluminium (Figures 20 and 21).
Adhesion problem is one of the major experienced challenges
of EN plating especially when the substrate is aluminium alloy.
The cast aluminium alloy has greater challenges of EN plating
than the wrought aluminium materials. Cast surfaces are specially
prepared by cleaning in diverse reagents and followed by surface
activation. It has been identiied that the single zincate treatment
by using the basic zincate solution resulted in such poor adhesive
strength of the electroless nickel-phosphorus plated ilm as to
peel off the substrate due to its residual stress as compared with
the double zincate treatment [23, 24]. In light of overcoming
abnormalities such as poor adhesion, porosity, ilm discontinuity
resulting from EN deposition, it has been suggested that some
procedure has to be applied [25]. Using a variety of sensitizing
solutions and the catalytic solution, a metal (nickel) is deposited
electrolessly on the sensitized catalyzed surface by immersion in
the metallizing bath for ixed amounts of time.
4.0 CONCLUSION
EN has been deposited on the cast aluminium substrate in sodium
hypophosphite bath. With the variation in the surface inishing,
temperature and different types of surfactants, the results show
that that the amount of EN deposition per unit area is dependent
on both the Al Alloy type and roughness of the surface of the
Aluminium alloy substrates used, temperature and the types
of pre-treatment surfactant. On the other hand, such properties
as the adhesion, porosity, colour and brightness are not solely
controlled by the surface polishing grits. In some instances,
rough polishing grit produced improved and more irm, tenacious
coatings than the smooth polishing grits. Of the six surfactants
tested, zincate and palladium chloride solutions produced the
best of the results in terms of the plating quality porosity, colour,
adhesion and appearance. The zincate produced relative higher
amount of EN depositions than the chloride on six (120-800µm)
of the eight grits tested. Zincating on cast aluminium substrate
prior to EN-plating as it has been reported to be result oriented
and hence, encouraged for better adhesion. The SFG variation
seems to have similar trend of EN deposition on AR and AC
samples operated at 85oC plating temperature. The 90oC plating
temperature produced highest values of EN deposition per unit
area on a range of 220-1200µm grits polished Al alloy surfaces.
EN deposition on AR and AC is not solely dependent on the
increase in level of the polishing grit.
ACKNOWLEDGEMENT
The authors would like to express their since gratitude to the
staff of following laboratories and establishments. These
include: Engineering Materials Development Institute (EMDI),
Akure. Project Development and design Laboratory, Materials
and Metallurgy division, Federal Institute of Industrial Research,
Oshodi. (FIIRO), Lagos. The premier wings engineering
services, Ado Ekiti.
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PROFILES
AJIBOLA OLAWALE OLAREWAJU is a Lecturer II in the Department of Materials and Metallurgical Engineering, Federal University OyeEkiti (FUOYE), Nigeria. He holds Master’s degree (M. Eng) in Metallurgical and Materials Engineering from the Federal University of Technology,
Akure (FUTA) in 2008 and currently a Ph.D student of Metallurgical and Materials Engineering (Surface Engineering/Hard coatings) at FUTA. He
is a Member of the Nigerian Society of Engineers and registered by the Council of Regulation of Engineering in Nigeria (COREN). He has worked
in various capacities as a Lecturer in the Department of Mineral Resources Engineering at Federal Polytechnic, Ado Ekiti for more than a decade
before he joined the FUOYE in January, 2013. He had over 30 relevant academic publications in learned journals and conference proceedings.
OLORUNTOBA DANIEL TOYIN is a Senior Lecturer in the Department of Metallurgical and Materials Engineering, Federal University of
Technology, Akure (FUTA), Nigeria. He holds PhD (2009) in Metallurgical and Materials Engineering from FUTA and a post doctoral fellow at
CMME Dept., Tshwane University of Technology, Pretoria, South Africa. He is registered by the Council of Regulation of Engineering in Nigeria
(COREN) and other professional bodies. He has worked in various capacities as a Lecturer. He had over 25 academic publications in learned
journals and conference proceedings.
ADEWUYI BENJAMIN OMOTAYO is a Professor at Metallurgical and Materials Engineering Dept., Federal University of Technology, Akure
(FUTA), Nigeria. A distinguished Fellow of the Material Society of Nigeria (FMSN). All his appointments were based on his excellent academic
records coupled with his academic zeal and passion for research, teaching and community engagement. He is registered by the COREN. Research
interest focuses include the development and characterization of alloys and materials suitable for structural applications in the building, automobile
and oil and gas industries. Particular interest in processing and process simulation of materials; Alloy Development; Composite Developmentbioibres for reinforcement; Nanotechnology; Development of Corrosion Inhibitors using Biomaterials. He has many peer–reviewed journals and
facilitator of conferences and publications. He is a professional member of national and international societies.
46
Effect of Grinding on Workability and Strength of Penang Rice
Husk Ash Blended Concrete Grade 30
Rahizuwan Hamid1, Norisham Ibrahim2
1
Faculty of Civil Engineering, 2Faculty of Civil Engineering Universiti Teknologi MARA
40450 Shah Alam, Selangor Malaysia, [email protected]
ABSTRACT
The practice of replacing with conditioned waste materials in construction is well known for conservation of natural resources.
Ecological was damaged due to quarrying caused depletion of natural resources (limestone, iron ore, clay). Many researchers
proving that these by-products have pozzolanic properties which improve the quality of concrete. Global production of rice
husk is approximately 580 million tonnes a year and this is rising as the world population and consumption of rice increases.
This paper reports the effect of rice husk ash (RHA) grinding time on the workability and strength of concrete. Concrete mix
proportions were introduced with RHA and superplasticiser (Sp) as additives. Three RHA with different ineness, i.e. RHA1(5)
Sp, RHA2(5)Sp and RHA3(5)Sp were used for study .Based on analysis, it is found that the increasing of ineness decreases
the workability but increases the compressive strength of the concrete. The use of RHA3(5)Sp results in highest strength at
28 days, which is due to the better dispersion and illing effect as well as an increase in pozzolanic reaction. From the research,
it is shown that RHA has the potential to be a cement replacement material. The research has an important implication on
environmental for sustainability due to usage of waste product as construction material.
1.0 INTRODUCTION
Landill of waste is a problem to the environment. Hence, many
researchers are looking into the utilization of waste material.
Fortunately, from their studies, some of the waste materials have
pozzolonic characteristics due to the presence of SiO2, Al2O3,
MgO and Fe2O3[1]. Those wastes are agricultural by product
such as palm oil bottom ash (POBA)[2,3] and RHA [4-6]. The
husk of the rice is removed in the farming process before it is
sold and consumed. It has been found beneicial to burn this
rice husk in kilns for various purposes. The rice husk ash is then
used as a substitute or admixture in cement. Therefore the entire
rice product is used in an eficient and environmentally friendly
approach. Processes of burning rice husk were under control and
sustain at lower temperature. Reactivity of rice husk ash depend
on amorphous form and particle size of the material. Hence, iner
material cause high reactivity due to high speciic surface area
exposed for hydration. High production cost of cement causes
high cost in concrete construction industry.
By applying supplementary cementitious material (SCM)
concept, cement usage can be minimized or reduced while
the strength and durability of the concrete can be improvised
compared to the conventional concrete [7-9]. In addition it
reduces the concrete production cost as well as the negative
impact on the environmental [5,10,11]. So far, RHA has not
been utilized yet in the construction industry. The reason
for not utilizing this material may be probably due to lack of
understanding of the RHA blended concrete characteristic.
Many researchers have already published on properties of
the blended RHA concrete such as strength and durability.
However, only few researchers were found on the effect of RHA
ineness on the properties [12]. This paper highlighted the study
on the effect of ineness on the workability and compressive
strength of concrete which the ineness of RHA was obtained
based on the grinding method. The grinding times were varies
from 30, 60 and 90 minutes by using ball bearing mechanism.
The workability and compressive strength of Grade 30 N/mm²
concrete with partial cement replacement of RHA were reported.
2.0 MATERIALS AND MIx PROPORTIONS
2.1 Materials
Ordinary Portland cement (OPC) used in this work was a type
I cement. RHA was used as cement partial replacement which
replaced 5% of the cement content. Rice husk ash were ground
into 3 lots which were 30, 60 and 90 minutes times of grinding.
Crushed granite with maximum size of 10 mm with speciic
gravity of 2.4 for surface saturated density was used. Mining
sand was used which maximum size of 5 mm with percentage
passing 600 µm was 25%. SiO2 content is more than 92% where
the chemical analysis of OPC and RHA been extracted from
previous studies by Sumrerng et al., [13,14], Kartini et al., [5,6],
Habeeb et al., [12], Tuan et al., [15], Rukzon et al.,[16], and Abu
Bakar et al., [17] is shown in Table 1.
Rice husk was collected and transported from Bernas
factory at Kampung Bukit Tengah, Seberang Perai Tengah,
Penang, Malaysia. Abu Bakar et al., [17] suggested that
essentially amorphous silica can be produce by maintaining
or control the combustion temperature below 500°C. Study
done by Habeeb et al., [12], the RHA was burned in the mufle
furnace with incinerating temperature not exceeding 700°C.
In this research, incineration was self- sustained with the total
duration of 7 hrs at 250°C. The burnt RHA was later left inside
the furnace to cool for 24 hrs. After that, burnt RHA was divided
into 3 parts for grinding. RHA was grinded using Los Angeles
mill machine for 30, 60 and 90 minutes.
47
RAHIZUWAN HAMID; NORISHAM IBRAHIM
Two sizes of steel balls used for grinding; 25 and 12 mm
in diameter. For each lot, 1 kg of 25 mm and 0.5 kg of 12 mm
steel ball were used for every grinding time. In order to ensure
the uniformity and consistency of the RHA, necessary measures
were taken to control treatment include mass of RHA fed into
the ball mill, milling speed, thickness of rice husk layer in the
furnace during incinerating and the duration as well as the
temperature of incinerating.
Table 1: Chemical analysis of OPC and RHA
Oxides
OPC (%)
RHA(%)
SiO2
15.05 - 20.09
92.00 - 96.70
Al2O3
2.56 - 4.76
0.21 - 1.01
Fe2O3
3.42 - 4.00
0.05 - 0.21
MgO
1.25 - 1.27
0.37 - 1.59
CaO
65.41 - 72.17
0.41 - 1.28
Na2O
0.08 - 0.74
0.05 - 0.26
K2O
0.35 - 0.41
0.91 - 2.31
SO3
2.71 - 2.96
0.94 - 2.90
LOI
0.96 - 1.33
2.36 - 4.81
2.2 Mix proportions and curing
The OPC was partially replaced with pozzolans at the dosage
of 20% by weight of cementitious materials. The control OPC
concrete was designed to achieve 30 N/mm² using DOE method
[18]. Based on this method, cement content of 380 kg/m³ was
adopted to all mixes. The water binder ratio (w/b) of control
mix was 0.61 with a slump ranged 60-180 mm. Since, rice husk
being cellular in nature [4], the used of RHA tend to increase
water requirement therefore Sp need to be considered. The mix
proportions and abbreviations are given in Table 2. They were
demoulded at the age 1 day and cured in water maintained at
room temperature until the test aged.
Table 2: Concrete mix proportion
Materials
OPC (kg/m3)
RHA (kg/m3)
RESULTS AND DISCUSSIONS
4.1. Workability
The grinding of RHA increased its ineness and reactivity [10].
The longer RHA is ground, the iner RHA size obtained resulting
in increment of pozzolanic reactivity due to the higher surface
area of rice husk [12]. Since, rice husk being cellular in nature,
the use of RHA tend to increase water requirement therefore
Sp need to be considered. The slump design to achieved desire
range between 60 – 180 mm. The result was in the range of 150 50 mm. For the same percentage of RHA replacement, increment
of RHA grinding time decreases the concrete workability. There
are two reasons for this; its absorptive characteristic [6] and
ineness of its size as referred by Habeeb and Fayyadh [12] in
(Zhang et al., 1996; Ganesan et al., 2008). Both of these features
results in high water demand to wet the surface area of RHA.
According to Habeeb et al., [12] increases the speciic
surface area of RHA which therefore more water requires to
wet the surface area of RHA. Since, the water/binder ratio was
maintained, Sp was added up as aid to enhance the luidity. It
was found that Sp increase the slump of the irst mix (RHA
ground 30 minutes) by 10 mm in comparison with the control
mix. However, the slump decreases when the grinding time
increases as shown in Table 3. Sp is absorbed onto the cement
particles and impart a very strong negative charge which helps to
lower the surface tension of the surrounding water considerably
and thus greatly enhances the luidity of the mix [21]. As evident
in Table 3, it is seen that for the same amount of water and Sp,
and increase in the grinding time, decreases the slump reading.
Figure 1 shows some typical slumps for the various RHA
concrete.
Table 3: Slump and compressive strength of concrete mixes
Slump Density
(mm) (kg/m³)
Concrete Mix
7d
14d
28d
60d
140
2317.8
18.3
20.1
29.5
32.2
361
RHA1(5)Sp
150
2345.9
23.9
30.1
29.9
40.1
19
(90min)
RHA2(5)Sp
90
2384.9
24.9
29.2
34.1
44.3
RHA3(5)Sp
50
2428.3
26.1
29.2
40.6
47.1
RHA1(5)
Sp
RHA2(5)
Sp
RHA3(5)
Sp
380
361
361
0
19
(30min)
19
(60min)
Compressive Strength
(N/mm²)
OPC
OPC
955
955
955
955
Coarse aggregate (kg/m³)
560
560
560
560
Water (litre)
235
235
235
235
0
0.5
0.5
0.5
3.0 TESTING
3.1 Workability
The workability test is accordance to BS EN 12350-2[19] which
speciied for slump test to measure the desire slump.
3.2. COMPRESSIVE STRENGTH
For the compressive strength test, the cube samples of
100 x 100 x 100 mm were prepared in accordance with BS EN
48
4.
Mixes
Fine aggregate (kg/m³)
Sp (%)
12390-3 [20] using 3000 kN concrete compression machine.
Samples were tested at the ages 7, 14, 28 and 60 days.
Result pattern changes of slump with respect to grinding
time were shown in Figure 2. Table 3 shows the RHA 1(5)Sp
had highest slump because it was add with superplasticiser in
comparison to the concrete control even the RHA increases the
water demand in concrete. In comparison to the other mixes
contained RHA also shows RHA 1(5)Sp was highest slump
even the Sp was maintained. It shows that, RHA with shortest
grinding time absorb less water compare to others duration.
Hence, it can be concluded that RHA with 30 minutes grinding
time had bigger size among RHA and directly indicates that it
had smallest speciic surface area as been speciied by Habeeb et
al., [12] in their study. Hence, it proves the evidence increasing
grinding time increase the ineness thus directly increased the
speciic surface area of particles that increase water demand
[10,12,15].
EFFECT OF GRINDING ON WORKABILITY AND STRENGTH OF PENANG RICE
HUSK ASH BLENDED CONCRETE GRADE 30
Figure 1: The slump for various mixes of fresh RHA concrete
Figure 2: Effect of grinding times to the slump of concrete
4.2. COMPRESSIVE STRENGTH
The results of the compressive strength for the various mixes
of grade 30 were presented in the Table 3 and Figure 3. RHAs
concrete with Sp from Figure 3 are well above the target
strength of 30 N/mm² at 28 days. The strength of concrete can be
discussed in term of in the early age strength (7 and 14 days) and
late age strength (28 and 60 days). At early age, the compressive
strength of concrete containing RHA increases tremendously
with respect to the grinding time. It is due to the ineness of RHA
particles that have high speciic surface area which increases and
fasten the pozzolonic reactivity. At the age of 28 days, it is found
that the concrete mix containing RHA ground for 90 minutes
(longest period) shows the highest compressive strength which
is 40 N/mm². Normally, compressive strength increases as the
grinding time of RHA also increases [12]. It can be seen that
the combination of RHA and Sp effect of compressive strength
contribute from inclusion of Sp while maintaining w/b 0.61 i.e.
29.9 N/mm² for RHA 1(5)Sp, 34.1 N/mm² for RHA 2(5)Sp and
40.6 N/mm² for RHA 3(5)Sp concrete at age 28 days. Thus
suggesting that inclusion of Sp is important to maintained
under same water cement ratio condition. Finer RHA, water will
be absorb more. Hence, if the quantity of water was maintained,
the increasing if ineness will reduce the luidity which the
water should be add in order to maintained desire slump. But
then, the w/b ratio was maintained in this study. Improvement
of workability was done by adding Sp into the concrete mix.
Hence, water was not added thus the strength of the concrete
was not affected. In addition of that Sp improves the strength.
It was due to the fact that adding Sp (while keeping w/b ratio
constant), it enhances the luidity of the mix even the increasing
ineness of RHA due to grinding time that cause loosing of water
demand (reduce slump),thus improved the workability and the
strength [4,5].
From Figure 3, compressive strength also reached target
strength at 14 days for all RHA concrete mixes but the rate of
increasing was varies. RHA 3(5)Sp show high growth rate of
compressive strength. Since, RHA was pozzolans, it contribute
additional formation of calcium silicate gel (C-S-H) that
contribute to the development strength of the concrete because
the C-S-H gel was produce twice [1]. These gel volumes will
illing the void between cement matrix and cause the densiication
effect [1]. As been study by Habeeb et al., [12], the increasing
grinding time will increase ineness and speciic surface area.
Thus, the process of secondary hydration will be much better
with respect to the grinding time due to higher speciic surface
area.
Figure 3: Compressive strength of concrete mixtures
From Figure 4, the strength of concrete were below 30 N/
mm² but due to increasing to grinding time, the compressive
strength were increase even the increment was not drastic. At
age 14 days, the strength of concrete was static/ stagnant even
the grinding time was increase as in Figure 4. At 7 days, strength
of concrete increase tremendously due to additional C-S-H gel
produce from second hydration which totally depend on calcium
hydroxide [Ca(OH)2] produce from primary hydration [1,22] but
the strength are stop in increasing at age 14 days due to reduction
of Ca(OH)2 which mostly had been used by second hydration at
early age.
Generally, from Figure 4 it can be seen that the compressive
strength of all RHA concrete are well above target strength of
30 N/mm² and 40 N/mm² for age 28 and 60 days respectively.
According to Habeeb et al., [12], speciic surface area increase
when the ineness increased. The iner particles, the more
activity of pozzolanic hydration occur [10,15]. Therefore, higher
quantity of C-S-H gel produced which increased the strength
of the concrete. In comparison the activity of producing C-S-H
occur only once for control specimen. Sizes of RHA inluence
a lot to the rate of pozzolonic hydration (due to the surface area
being exposed to the chemical hydration) and some mechanical
properties of concrete [4-6]. Hence, it showing at late age,
secondary hydration received adequate Ca(OH)2 from primary
hydration which can be proved by additional of C-S-H gel due to
aggressively increment in strength. However, this increment of
strength was developed with the aid of curing process for every
age had been tested.
5.0 CONCLUSIONS
It can be concluded that the differences of grinding times produced
different ineness. Fine rice husk ash reduces the water binder
ratio (w/b) and improved the strength compared with coarser rice
husk ash. The used of RHA3(5)Sp results in a good strength in
comparison with other RHAs owning to the better dispersion and
49
RAHIZUWAN HAMID; NORISHAM IBRAHIM
Figure 4: Effect of grinding times to the compressive strength at
different days
iller effect despite an increase in the pozzolanic reaction. Due to
high speciic surface area of rice husk ash (RHA), the dosage of
superplasticiser had to be increase along with RHA ineness
to maintained desired workability. Increased in the grinding time
of RHA resulted in a dry and unworkable mixture unless Sp is
added. Maintaining of Sp into RHA concrete while sustaining
water binder ratio but increase in grinding time decreased the
slump and interrupts the cohesiveness of the concrete.
6.0 ACKNOWLEDGEMENTS
The authors would like to acknowledge the Faculty of Civil
Engineering, Universiti Teknologi MARA and Bernas Sdn.
Bhd. in the form of research support, guidance, cooperation and
materials for the study.
[7]
Bhaskar Sangoju, Ravindra Gettu, B. H. Bharatkumar and M.
Neelamegam (2011). “Chloride-Induced Corrosion of Steel in
Cracked OPC and PPC Concretes: Experimental Study.” Journal
of Materials in Civil Engineering, July 2011: pp1057-1066.
[8]
Gangné, R., Ollivier, J., Latreiile, Y.(1998). “Effect of
Superplasticiser, Retarding Agent and Silica Fume on the Air
Permeability of High Performance Concrete.” American Society
For Testing And Materials (ASTM), pp248.
[9]
Gjorv, O. E., Tan, K., and Monteiro, P. J. M.(1994). “Effect of
Elevated Curing Temperature on the Chloride Permeability of
High-Strength Lightweight Concrete.” Cement, Concrete and
Aggregates, CCAGPD. Vol. 16, No. 1: pp57-62.
[10] Chindaprasirt, P., Jaturapitakkul, C. and Rattanasak, U(2009).
“Inluence of Fineness of Rice Husk Ash and Additives on the
Properties of Light Weight Aggregates.” Construction and
Building Material 88. Pp158-162.
[11] A.A.Ramezanianpour, M.Mahdi Khani and Gh.Ahmadibeni
(2009).”The Effect of Rice Husk Ash on Mechanical Properties
and Durability of Sustainable Concretes”. International Journal
Of Civil Engineering.Vol.7, No.2: pp83-91.
[12] G.A. Habeeb and M.M. Fayyadh, Rice Husk Ash Concrete (2009).
“The Effect of RHA Average Particle Size on the Mechanical
Properties and Drying Shrinkage.” Australian Journal of Basic
and Applied Science. 3(3) : pp1616-1622.
[13] Sumrerng Rukzon And Prinya Chindaprasirt (2010).” Strength
and Carbonation Model of Rice Husk Ash Cement Mortar with
Different Fineness.” Journal of Materials in Civil Engineering.
March 2010: pp253-259.
[1]
A.M.Neville.(2010). Properties of Concrete, England, 4th Ed.,
Pearson Prentice Hall.
[14] Sumrerng Rukzon, Prinya Chindaprasirt and Tattana Mahachai
(2009). “Effect of Grinding on chemical and Phisical Properties
of Rice Husk Ash.” Journal of Materials in Civil Engineering.
Volume 19, No.2: pp242-247.
[2]
Mohd. Warid Hussin, Khairunisa Muthusamy, Fadhadli Zakaria
(2010). “Effect of Mixing Constituent Toward Engineering
Properties Of POFA Cement-Based Aerated Concrete.” Journal
of Materials In Civil Engineering. April 2010: pp287-295.
[15] Tuan, N.V., Ye, G., Breugel, K.V, Fraaij, A.L.A, Dai, B.D(2011).”
The Study of Using Rice Husk Ash to Produce Ultra High
Performance Concrete.” Construction and Building Material 25.
Pp 2030-2035.
[3]
M. A. Megat Johari, Nurdeen M. Altwair, S.F.Saiyid Hashim
(2012). “Flexural Performance Of Green Engineered Cementitous
Composities Containing High Volume Of Palm Oil Fuel Ash.”
Construction and Building Material, Vol.37: pp518-525.
[16] Rukzon, S. and Chinaprasirt, P (2010).” Strength and Carbonation
Model of Rice Husk Ash Cement Mortar with Different Fineness.”
Journal of Material in Civil Engineering (ASCE). Pp 253.
[4]
Kartini, K. (2011). “Rice Husk Ash-Pozzolanic Material For
Sustainability.” International Journal Of Applied Science and
REFERENCES
Technology. Vol.1, No. 6: pp169.
[5]
Kartini K., Mahmud H.B., Hamidah M.S.(2010).” Absorption
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Blended Grade 30 Concrete.” Journal of Engineering
Science and Technology. Vol. 5, No.1: pp1-16.
[6]
Kartini, K., Mahmud, H.B., Hamidah, M.S.(2006). “Strength
Properties of Grade 30 Rice Husk Ash Concrete.” 31st
Conference on Our World In Concrete & Structure, 16-17
August 2006, Singapore.
[17] Badorul Hisham Abu Bakar, Ramadhansyah PutrajayaC and
Hamidi Abdul Aziz (2010). “Malaysian Rice Husk Ash –
Improving the Durability and Corrosion Resistance of Concrete:
Pre-Review.” Concrete Research Letters. Vol. 1 (1): pp6-13.
[18] Department Of Environment (DOE) (1992). Design Of Normal
Concrete Mixes. BRE Publication, United Kingdom.
[19] British Standard Institution, BS EN 12350-2:2009. Testing Fresh
Concrete. Slump Test. [20] British Standard Institution, BS
EN 12390-3:2009. Testing Hardened Concrete. Compressive
Strength of Test Specimen.
[21] Superplasticiser in Concrete, The Aberdeen Group Laboratory,
1978.
[22] P. Kumar Mehta and Paulo J.M. Monteiro (2006). ConcreteMicrostructure, Properties and Materials, 3th Ed., McGraw
Hill, New York.
50
EFFECT OF GRINDING ON WORKABILITY AND STRENGTH OF PENANG RICE
HUSK ASH BLENDED CONCRETE GRADE 30
PROFILES
RAHIZUWAN HAMID is an assistant director at Cawangan Pangkalan Udara dan Maritim, JKR Headquarters Malaysia. He is also structural
designer/engineer for most of his branch project which involved in maritime work. He experienced in designing precast jetty, breakwater,
revetment, retaining wall, concrete bridge and so forth. He is also currently doing his PhD in forensic engineering regarding on structural retroitting
technology from University Science Malaysia. He obtained his Diploma in Civil Engineering (Design) from Universiti Teknologi MARA at 2010.
Then his degree, B.Eng(Hons)(Civil) major in concrete from Universiti Teknologi MARA also. He pursued his postgraduate study in Master of
Science (Structural Engineering) at University Science Malaysia and graduated in 2013.
NORISHAM is a lecturer of Structural Design at the Faculty of Civil Engineering, Universiti Teknologi Mara, Shah Alam. She is also currently
the Coordinator for the subject of Basic Timber and Steel Design. She obtained her B.E (Civil Engineering) and MSc (Structural Engineering) from
Universiti Sains Malaysia.
51
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