Gravity Environments - Island Software Group

Transcription

Splashless In Space: The Impact Behavior of Large
Droplets on a Rigid Surface in Low-Atmosphere, LowGravity Environments
Topic Area: Fluid Dynamics
A Proposal for the 2007 NASA Reduced Gravity Student Flight
Opportunities Program
Fairfield University
Physics Department
1073 North Benson Road
Fairfield, CT 06824
Team Contact:
Brendan Hermalyn
[email protected]
(203) 623-4794
Faculty Advisor:
Dr. Leslie Schaffer
[email protected] (203) 615-4034
Team:
Hermalyn, Brendan
Flyer / Senior / Physics Major
Hunter, Brittany
Alt. Flyer / Senior / Physics Major
[email protected],
[email protected]
[email protected]
Kurose, Jessica
[email protected]
Stupak, John
[email protected]
Zaffetti, Michael
[email protected]
As advisor for this project, I support and endorse this proposal.
_
Dr. Leslie Schaffer
Date
Table of Contents
0. Miscellaneous...................................................................................................................................................4
0.1 Flight Week Preference ..............................................................................................................................4
0.2 Mentor Request ...........................................................................................................................................4
0.3 Table of Variables.......................................................................................................................................4
I Technical .............................................................................................................................................................5
I.1 Abstract. .......................................................................................................................................................5
I.2 Test Description ...........................................................................................................................................5
I.2.A Introduction and Background ............................................................................................................5
I.2.B Theory..................................................................................................................................................7
I.2.C Hypothesis ...........................................................................................................................................9
I.2.D The Need for Microgravity ................................................................................................................9
I.3 Test Objectives ...........................................................................................................................................10
I.3.A Aim of Experiment ...........................................................................................................................10
I.3.B Follow Up Justification ....................................................................................................................11
I.3.C Ground-Based Experiments .............................................................................................................11
I.3.D Expectation of Results......................................................................................................................12
I.3.E Experimental Design and Procedure................................................................................................15
I.3.E.1 Experimental Apparatus ...........................................................................................................15
I.3.E.2 Experimental Procedure ...........................................................................................................16
I.3.E.3 Additional Considerations ........................................................................................................19
I.3.E.4 Experiment Flight Plan .............................................................................................................19
1.3.F Analysis of Quantitative/Qualitative Data Collected .....................................................................20
I.4 Justification for Follow-Up Flight ...........................................................................................................21
I.5. References .................................................................................................................................................21
II. Safety...............................................................................................................................................................24
II.1 Flight Manifest .........................................................................................................................................24
II.2 Experiment Description/Background......................................................................................................24
II.3 Equipment Description ............................................................................................................................24
II.4 Structural Design .....................................................................................................................................31
II.5 Electrical System ......................................................................................................................................31
II.6 Pressure/Vacuum System .........................................................................................................................32
II.7 Laser System .............................................................................................................................................32
II.8 Crew Assistance Requirements................................................................................................................32
II.9 Institutional Review Board ......................................................................................................................33
II.10 Hazard Analysis .....................................................................................................................................33
II.11 Tool Requirements .................................................................................................................................35
II.12 Ground Support Requirements..............................................................................................................36
II.13 Hazardous Materials .............................................................................................................................36
II.14 Procedures..............................................................................................................................................36
II.14.1 Ground Operations.........................................................................................................................36
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II.14.2 Pre-Flight Operations.....................................................................................................................36
II.14.3 In-Flight Operations.......................................................................................................................37
II.14.4 Post-Flight Operations ...................................................................................................................37
III Outreach Plan. ..............................................................................................................................................38
III.1. Objective.................................................................................................................................................38
III.2 Website.....................................................................................................................................................38
III.3 Partnerships ............................................................................................................................................39
III.3.A.The Discovery Museum ................................................................................................................39
III.3.B Bridgeport School District.............................................................................................................39
III.3.B Fairfield High Schools ...................................................................................................................40
III.4 Target Audience ......................................................................................................................................40
III.5 Connection to Curriculum......................................................................................................................41
III.6 Activities ..................................................................................................................................................42
III.7 NASA Education......................................................................................................................................45
III.8 Press Plan................................................................................................................................................46
III.9 Milestone Timeline..................................................................................................................................47
IV. Administrative Requirements: ..................................................................................................................48
IV.1 Institutional Letter of Endorsement. ......................................................................................................48
IV.2 Statement of Supervising Faculty...........................................................................................................48
IV. 3 Funding/Budget Statement ....................................................................................................................48
IV.4. Experiments Involving Animals.............................................................................................................49
IV.5 Parental Consent Forms........................................................................................................................49
V. Appendices .....................................................................................................................................................50
V.1 Appendix A ................................................................................................................................................50
V.2 Appendix B ................................................................................................................................................52
V.3 Appendix C................................................................................................................................................53
V.4 Appendix D................................................................................................................................................54
V.5 Appendix E ................................................................................................................................................57
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0. Miscellaneous
0.1 Flight Week Preference
1. Flight Group 1 – March 8 – 17, 2007
2. Flight Group 2 – March 22 – 31, 2007
3. Flight Group 3 – April 19 – 28, 2007
Note: Flight Group 1 overlaps with Fairfield University’s Spring Break. Being chosen
for Flight Group 1 would mean we would only have to miss 2 days of class rather than 7.
This would be by far the most convenient group and cause the least interference with our
schoolwork. However, if this is not possible, we are prepared to take part in either group
2 or 3.
0.2 Mentor Request
We would like to request the assistance of a JSC scientist or engineer as a mentor.
0.3 Table of Variables
Variable
ΣG
ΣL
γ
T
kB
Mair
P
V0
R
σ
νethanol
Description
Destabilizing stress due to
compressibility of gas
Stabilizing stress due to surface tension
Adiabatic constant of air
Temperature of air
Boltzmann's constant
Molecular weight of gas
Pressure of gas
Velocity of drop on impact
Radius of drop
Surface tension coefficient of ethanol
Kinematic viscosity of ethanol
Table 0.1. Variables used in proposal.
Note: Any pressure mentioned in this proposal refers to atmospheric pressure.
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I Technical
I.1 Abstract.
Our proposal is to investigate the physics of large scale liquid drop impacts upon
a smooth dry surface. As a drop of liquid impacts a smooth dry surface, a crown shaped
splash emerges as the drop collapses. A rather surprising phenomenon, however, was
discovered in 2005: when the atmospheric pressure around the impact is decreased, the
splash ceases to occur. There seems to exist a relationship between the splash
characteristics and the atmospheric conditions. This relationship governs the threshold
pressure, which is the atmospheric pressure at which a splash no longer results. One of
the key parameters is the size of the drop. Previous ground based experiments have been
limited in drop size due to the effects of gravity, which acts to detach a drop from an
injector when the weight of the drop surpasses the adhesive force of the liquid. While
strides are being made in understanding this phenomenon on Earth, particularly with
smaller droplets, it has not been possible to test the threshold scaling with larger drops.
We propose to use the microgravity environment onboard the DC-9 to scale the drop
sizes much larger than is possible on a ground-based lab to verify and extend our
understanding into the regime of large drop sizes. Using a variation on an experimental
setup proven in a previous microgravity experiment, we will form drops up to 5 times the
previously tested size, into the gravity limited drop size regime, and impact them on a
smooth dry surface at constant velocity. This process will be repeated while capturing
the impacts on a high speed camera, varying the atmospheric pressure by ±10% in 2%
increments from the theoretically calculated threshold pressure (see Plot I.3.1). Followup image processing will let us confirm or reject the expectations. With many
applications, ranging from printing and surface coating to wing icing on airplanes,
verification and further refinement of this model would be a welcomed contribution to
the science community.
I.2 Test Description
I.2.A Introduction and Background
Intuitively, one would expect a splash to result from a drop falling onto a solid
surface. Under normal conditions (standard atmospheric pressure), this expectation
proves true. When a drop hits a smooth, dry substrate a corona splash occurs. After the
drop contacts the surface, the fluid can spread upward to form a crown, which (in most
cases) then breaks up into a spray of droplets.
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Figure I.2.A.1 Falling drop of milk, illuminated by a strobe light, photographed by
Harold E. Edgerton, c. 1938. [2]
We see splashes so frequently that we rarely think twice about the occurrence.
This causes us to overlook much of the complexity inherent in the collision and
subsequent splash. While many experiments have been conducted that attempt to
explain, once and for all, the physics of droplet splashing, we still do not fully understand
what exactly causes the effect.
In 2005, a team of researchers from the University of Chicago MRSEC
composed of physicists Xu, Zhang, and Nagel, made the surprising observation that when
pressure is lowered enough, splashing can be completely eliminated[20,21]. The
dependence of the splash on surrounding gas had not been previously recognized or
studied, and their groundbreaking paper on this subject was cited as one of the 10 best in
2005 by the American Institute of Physics. As pressure is reduced, less of a splash forms
from the drop impact and fewer droplets break free. If the pressure is reduced
sufficiently, the drop simply flattens out and spreads over the impacting surface in a
fairly uniform way.
These observations have lead to a model of splashing that takes two types of
stresses into account, which will be discussed in depth below. First, there are the
compressible effects of the surrounding gas which acts to both destabilize the drop and
push it upwards. Second, there is a stabilizing stress from the surface tension of the
liquid which encourages the fluid to remain together. When destabilizing pressures
outweigh stabilizing forces, a splash is predicted to occur. As destabilizing stresses are
lowered, surface tension begins to dominate and splashing is inhibited.
Understanding exactly how this works has great importance in industry. Drop
impact and splashing is related to “ink-jet printing, soil erosion by rain, spray cooling,
annealing, quenching and painting, shock atomization, combustion engines, meteorology,
and underwater noise of rain” [22], among others. For example, internal combustion
engines can apply this research to break fuel droplets into smaller, more potent mists by
increasing pressure, and precision painting or covering techniques could benefit from a
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low pressure, splashless environment. Our experiment will extend the knowledge of this
effect into a regime that cannot be tested well on Earth.
I.2.B Theory
To understand why a splash forms, we must look at the stresses present during a
droplet impact. The researchers at the University of Chicago hypothesized a relationship
between two forces: stabilizing (surface tension) and destabilizing forces (gas
compression) [20,21].).
A droplet in mid air is held together by surface tension. This is a stabilizing force
in that it keeps the droplet together. It is modeled as a:
#L =
"
"
=
d
! Lt
(1)
Where the surface tension of the liquid is divided by the boundary layer thickness, which
is dependent on the viscosity and shear rate of the liquid.
When the droplet impacts a smooth and dry surface, however, it compresses the
gas near the surface and forms a shock wave as the gas expands and escapes from
between the liquid and the surface. To model the shock wave, three elements are looked
at
The density of the gas, which changes due to compression:
!G =
PM G
k BT
The speed of the shock wave, which is the velocity of sound in the surrounding gas:
CG =
"k B T
MG
And the velocity of the expanding liquid, which contributes to the destabilizing stress.
!
Ve =
RV0
2t
This leads to the force of the shock wave:
"G # ( $G )(CG )(Ve ) #
!
PMG
kB T
%k B T
MG
RV0
2t
(2)
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Upon impact the droplet experiences both the stabilizing force of surface tension, which
tries to keep all of the molecules together, and the destabilizing force of the shock wave,
which effectively tries to rip the droplet apart. Under normal conditions, as we can
readily observe, the stress of the shock wave is sufficient to overcome the force of surface
tension and the droplet breaks up and splashes. The University of Chicago team,
however, observed that when the pressure drops below a certain critical limit, the splash
ceases to occur; in other words, the stabilizing surface tension is stronger than the
destabilizing shockwave. This leads us to a relationship between these stresses,
expressed as a ratio:
Destabilizing Stress "G
RV0 $ L
=
= #M G P
Stabilizing Stress
"L
2kB T %
(3)
The threshold ratio where the splash no longer occurs has been empirically shown
to be 9/20 or 0.45. Above this threshold, splashing will occur. Using this threshold ratio
the !
Group at the University of Chicago found good agreement between their splashing
predictions and experimental results by varying the gas inside the chamber, the velocity
of the drop (by releasing it from different heights), the liquid used for the drop, and the
pressure.
Because their experiment was ground-based, they could only test their hypothesis
over a limited range of radii. They have noticed that at very low velocities with regular
and small drop sizes, the splashing effects are no longer modeled by this equation.
Presently there are additional studies being conducted on scaling the drop size down to
see if the physics holds in the extremely small regime.
It is very difficult if not impossible to test this model for much larger drop radii on
Earth due to gravity, and thus the positive scaling of this relationship has been
unconfirmed. We propose to greatly increase the range of radii over which to test their
hypotheses by making use of microgravity, thereby gaining greater insight into the
dependence of splashing on drop size. We expect their relationships to hold with
increased drop sizes, but then again, it may very well turn out that there is an upper limit
on drop size, beyond which the physics of this model breaks down. If so, we hope to
determine this upper limit and hypothesize a modified model which accurately predicts
the behavior of large drops.
We will test this model by calculating the threshold pressure. Keeping in mind
the observed 9/20 ratio, one can solve the equation above for the threshold pressure:
PT = .45 "
#
2k B T
"
RV% L
$M G
(4)
This will be measured by varying the pressure by ±10% of the calculated threshold
pressure from above in 2% increments while keeping all other variables constant and
observing the impact to!determine if a splash occurred or not.
There have simply not been very many tests of this newly discovered
phenomenon. Previous studies of splashing almost unanimously ignore the effect of the
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compressed gas on the droplet, instead citing a shockwave that propagates in the fluid
alone [3,5]. This new model has far reaching implications on understanding splashing,
with the newfound ability to suppress or support splashes by simply varying the
atmospheric pressure.
I.2.C Hypothesis
By determining the threshold pressure of larger drop sizes, we hypothesize that
we will be able to test the splashing model proposed by the University of Chicago team,
and expand the understanding of the physics of this phenomenon into a larger regime
than possible on Earth. We expect that our results will confirm the model and that the
experimental threshold pressures will agree with theoretical values, but we will be testing
over a range of pressures wide enough to observe a noticeable difference between the
theoretical and experimental results, if one exists. If there is a discrepancy, we hope to
create a modified model that depicts splashing effects more accurately.
I.2.D The Need for Microgravity
We will be using the microgravity environment onboard the DC-9 to create
spherical droplets much larger then what can be formed on Earth. This is a proven and
time tested application of microgravity. [6,10]
The most common method for producing droplets is using an injector or syringe
apparatus. A drop is formed on the tip of a needle until it grows so large that gravity
overcomes the adhesive surface tension forces, and causes the droplet to fall. Therefore,
there exists a maximum size of a droplet that can be formed on a needle. This is dictated
by Tate’s Law:
W=2πrγ
(5)
where W is the weight of the drop, r is the radius of the tip of the needle, and γ is the
surface tension of the liquid. [18]
By knowing the density of the liquid used, one can calculate the volume of the droplet.
We can also rearrange the equation to find the radius of the drop,
rd = 3
3rn "
2 !g
where rd is the radius of the drop and rn is the radius of the needle tip. For a needle with a
radius of .4mm, the largest ethanol drop which can be formed has a radius of .954mm.
Using the same size needle, we will be able to produce drop sizes much larger. The
largest drop size we will form is 8.5mm.
Although other methods of forming large droplets in Earth gravity do exist, they
are not particularly useful for this application. First, they tend not to produce very
spherical droplets. A major condition of this experiment is that the droplets impact the
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glass substrate as, or most nearly as a sphere. In past ground based experiments on
splashing, the height from which the drops were released was adjusted to account for
harmonic oscillation in the direction of motion so that the droplet impacted the substrate
“in between” oscillations, and thus, as a sphere. [20,21] Thus, several methods for large
droplet production in Earth gravity, including sonic levitation, and simple valve
mechanisms, which quickly release a quantity of water, are not usable.
Even if a large droplet is formed into a perfect sphere, when it is accelerated due
to gravity, it will deform and possibly break apart by the same destabilizing forces that
make it splash. These effects will ruin the symmetry of the experiment, and will not yield
the results we are looking for.
Although the role of gravity is not mentioned in the past research on splashing
phenomena, we are also interested to see if it plays a previously unidentified role in
splashing. Gravity could well be a dampening force on the rebound splash. As stated
above, this is new physics that we are seeking to understand. The reduced gravity
environment will allow us to not only scale the drop sizes but observe differences
between the ground based control tests, including experiments by other groups as well as
our own preflight testing, and the trials run in microgravity.
These factors make the microgravity environment an ideal place to study
splashing effects in low atmospheric conditions. It allows us to form large droplets, as
we can make them effectively as large as we want, allow them to come to spherical
equilibrium, then cause them to impact upon the glass surface by moving the vacuum
chamber, rather then actually moving the droplet. As this is not possible on Earth, we
will expand the testable regime of this phenomenon by a factor of 5 over what was
previously tested. In addition, we may also be able to notice subtle effects of gravity
upon the splashing phenomenon, which we hope to quantify and incorporate into the
model.
I.3 Test Objectives
I.3.A Aim of Experiment
Although the model that Xu, Zhang, and Nagel developed holds for the
experimental data they were able to collect, they were not able to test all ranges of
variables. Because their experiments were conducted in regular gravity, they were
limited in the size of the drops they were able to test, namely they could not test drops
larger than 3.4 mm in diameter. Under standard Earth gravity, the weight of the drop
pulls it off the drop injector before its mass, and therefore its size, can get too large. In
microgravity, we will be able to form larger drop sizes[6] and test the scaling of their
proposed model. Therefore, the aim of this experiment is to test the physics of splashing
effects in a drop size regime previously untested.
We have been in contact with the University of Chicago team, and they agree that
our results from this experiment will greatly help in understanding the phenomenon. Our
experiment will test four different drop sizes, 1, 2, 3, and 5 times the size of the drop
tested in the ground based lab. We will test the model by observing the difference
between the calculated and observed threshold pressure for each drop size. All other
parameters will remain constant throughout. High-speed photography will allow us to
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observe the experimental threshold pressure. A plot of threshold pressure vs. drop size
will be created and compared with the expectation graph.
This is an exciting experiment, as we are combining new science with a novel
application of microgravity to expand the range of understanding of a phenomenon. This
is the first time this experiment will be conducted for large drops at all, let alone in a
microgravity environment.
I.3.B Follow Up Justification
To the best of the authors’ knowledge, this experiment has never been tested
microgravity. It is a novel application of microgravity to test a newly discovered
phenomenon. This is also the first proposal submitted to the NASA Reduced Gravity
Student Flight Opportunities Program by a Fairfield University team.
I.3.C Ground-Based Experiments
The original experiment of this type was conducted under standard Earth gravity
by researchers at the University of Chicago [20,21]. Xu, Zhang and Nagel created drops
of the same size and spherical shape while varying other parameters, including the
velocity of the drop at impact, different gases and liquids, and most importantly, the
pressure of the surrounding gas. To determine the threshold pressure, the University of
Chicago team kept the drop size and all other variables constant, but varied the pressure
for each trial until the pressure at which the splash no longer occurs was found. A highspeed camera was used to capture the behavior of the liquid at the moment of impact.
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Figure 1.3.B.1. Photographs depicting the dependence of splashing on atmospheric
pressure. Each row shows the time evolution of a single alcohol drop impacting on a
glass substrate. [21]
In Figure 1.3.B.1, the top row shows a drop under normal atmospheric conditions, where
splashing clearly occurs. The proceeding rows depict drops impacting under decreased
atmospheric pressure, and splashing can also be seen to decrease, until finally the
threshold pressure is reached and no splashing results. [21]
Figure 1.3.B.2. A blowup of picture top row, second from left, correlating to standard
atmospheric pressure at time t = 0.726 ms. Note the crown deflected upwards by the air
pocket, as indicated by the red arrows. [21]
I.3.D Expectation of Results
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Plot I.3.1. The threshold curve: Atmospheric Pressure vs. Drop Diameter. Note the
inverse square root relationship. We will be testing one drop size as they did on Earth,
then scaling the drop size by factors of 2, 3, and 5. Below the plotted curve, no splashing
occurs; above the curve, splashing does occur. The area to the left of the red line has
been tested under earth gravity. The area to the right of the red line has not yet been
possible to test. We will experimentally determine the shape of the curve in this region as
it conforms or deviates from expectation.
We expect to see results which confirm the model presented by researchers Xu, Zhang,
and Nagel. For the four different drop sizes of ethanol, we have calculated radii of R1x =
1.7mm, R2x = 3.4mm, R3x = 5.1mm and R5x = 8.5mm. (Please see appendix for scaling
these values for water). These size drops yield theoretical threshold pressures:
Diameter
(mm)
3.4
6.8
10.2
17
Threshold
Pressure (kPa)
41.91
29.63
24.20
18.74
From the high-speed photography of the drop impact at different pressures, we will be
able to determine the threshold pressure of the system to an accuracy of ±1% error. At
pressures higher than the threshold value, a corona splash will occur. At pressures lower
than the threshold value, no drops will be emitted from the drop impact, although at
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values near the threshold pressure, ripples will occur on the expanding rim of the
liquid[21].
The first drop size will function as our control, as it is the same size used in the
University of Chicago tests.
Another interpretation is to look directly at the ratio in Eq. 3 for each drop size:
Plot I.3.2. The expected stress ratios. Note expected threshold pressure when the stress
ratio is 9/20.
While we are testing Xu, Zhang and Nagel’s model and expect our result to
confirm their theory, we maybe also observe a deviation from their model. Although it is
very clear from their experiments that the presence of gas plays a significant role in
splashing, it is not completely clear that a shock wave must travel through the gas.
Perhaps the gas compresses and pushes back up against the drop but does not cause a
shock wave. Also, there is nothing in the stress ratios taking the compressibility of the
liquid into account. As Field, Lesser and Dear suggest, perhaps a shock wave travels
through the drop caused by the compressibility of the liquid [3,5]. By testing the
proposed model with larger drop sizes we may find inconsistencies or missing pieces
which are not observable with smaller drop sizes.
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Prior to arrival at the Johnson Space Center, we will conduct ground based tests using
our apparatus as a control, and to repeat and verify the results obtained by the University
of Chicago group.
I.3.E Experimental Design and Procedure
I.3.E.1 Experimental Apparatus
Our experimental design is a modification of an apparatus built to test water
droplets impacting on a thin sheet of water in microgravity, where it successfully
accomplished the task.[6] We have changed it to suit our needs, but there already exists a
proof of concept. We have discussed our design and procedure with the University of
Chicago team, [19] who agrees that it should be successful in gathering the data required
to confirm or deny our hypothesis in the 60 parabolic loops of 23 seconds of microgravity
each.
The experimental apparatus consists of an aluminum frame structure, a shockinsulating base, a belt drive shaft, an inertial sled, a vacuum chamber, a digitally
controlled injector, an impact apparatus, a high-speed digital camera, a digitally
controlled vacuum compressor, and an onboard computer system. The apparatus is
designed to mount horizontally on the floor of the aircraft. Once in microgravity
conditions, we will form a free-floating drop, and then accelerate an impact surface
towards the drop in a controlled manner, to simulate a drop ‘falling’ in gravity. The
impact surface is contained in a vacuum chamber, along with the drop injector, all of
which will move as a unit as controlled by the drive belt.
Figure I.3.D.1 A to-scale concept model of our experimental apparatus, with the
protective cover open, and the sled in the ending position
Figure I.3.D.1 is a to-scale front-view 3D model of our design concept. The following
components are highlighted:
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1.
2.
3.
4.
5.
6.
Computer
Drive Belt Controller
Drive Belt
Camera Controller
Camera Head
Vacuum Compressor
7.
8.
9.
10.
11.
12.
Power Supply
Impact Surface
Protective Case
Vacuum Chamber
Mirror
Injector
These components are detailed in sections II.3 - 6.
I.3.E.2 Experimental Procedure
To set up the apparatus for a particular trial run, we will need to first set the
pressure of the vacuum chamber using the digitally-controlled compressor. The chamber
has a fairly small volume of air, which will make it very quick and easy for our
compressor to control the pressure inside. Additionally, on each flight day we will be
testing two different drop sizes with one needle size for each day. This will eliminate the
need to switch needles. We will simply control the droplet size with the digital syringe,
which allows for very accurate volumetric measurements that provide us with a
repeatable drop diameter of only ±0.1mm. All computer equipment will be online and
idle prior to starting.
When the aircraft reaches microgravity, we will form a drop of a specified size.
The digitally-controlled injector is mounted inside the vacuum chamber and can produce
a drop size at the appropriate diameter in just a few seconds. Once fully formed, the drop
will be detached from the needle’s nose by producing a sharp and momentary
acceleration of the sled to dislodge the drop[6].
After the drop is formed and released, we will let it float freely for a short period
of time to stabilize into a sphere. A water droplet 1 cc in volume takes approximately
100 ms to stabilize. The time will be calculated for each drop size. Once in this position,
there is approximately 8 inches (20.32 cm) to accelerate the sled and chamber such that
the plate collides with the drop at velocity of 3 m/s. The required acceleration is easily
found using kinematics, as is calculated for ethanol:
2
2
V f = Vo + 2ad
m 2
) = 2a (0.2032m)
s
m
a = 22.15 2
s
(3
The maximum instantaneous force our drive shaft can apply to the belt is 2450 N; this
imposes a weight limitation of the inertial sled; we can verify that this will not be a
problem: our sled will weigh no more than 20.41 kg
Let us calculate the maximum weight for this acceleration.
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Fmax = mmax a
(2450 N ) = mmax (22.15
m
)
s2
mmax = 110.6kg
The available 8 inches to accelerate the sled is enough room. We can determine the
actual force we will need to give our sled:
F = ma
F = (20.41kg )(22.15
m
)
s2
F = 452.1N
Additionally, it will not affect the experiment if the sled is accelerating or in
constant velocity when we observe the collision between the plate and the drop. The time
interval over which we will make our observations is under 2ms, during which time the
presence of acceleration will introduce less than a 1.5% error in the velocity:
"V = at
"V = (22.15
E=
m
m
)(2 ! 10 #3 s ) = .0443
2
s
s
!v 0.0443 ms
=
= 0.0148
v
3 ms
The drop will remain 8 inches away from the collision plate until the sled begins
to move, assuming any initial velocity imparted on the drop was nullified or compensated
for. On our onboard computer, we will trigger the drive shaft to begin accelerating. The
software component that triggers the shaft will automatically activate our high-speed
digital camera (which is mounted on the sled and focused at the point of impact for the
drop) at the appropriate interval later:
1 2
at
2
2d
t=
=
a
d=
(0.2032m)(2)
m
22.15 2
s
t = 0.135s
The computer will trigger the belt through a PLC controller, and then wait the
predetermined interval to activate the camera. The computer will stop the camera 2 ms
after the drop impact. All the data will be bounced to the computer and saved on the hard
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drive in uncompressed format. This storage method requires approximately 8GB / 3
seconds of recording, so for 30 trials with recording in the order of milliseconds, a typical
hard drive will be plenty to store the uncompressed images. The sled will have moved a
total of:
1 2 1
m
at = (22.15 2 )(0.135s ) 2
2
2
s
d = 0.202m
d=
We will use the remaining distance to decelerate the sled as slowly as possible, a
deceleration which will be automatically initiated after the impact by the onboard
computer. The full running length of the sled is 48cm. The deceleration needed to stop
the sled is equal to:
v 2f = v02 + 2ad
m
)(0.137 s )]2 + 2(a )(0.48m ! 0.202m)
s
m
a = !16.56 2
s
0 = [(22.15
The majority of the drop liquid will stick to the impact surface due simply to
adhesion compared to this deceleration rate. Should any liquid from the drop leave the
surface as the sled decelerates, it will collide with the sponge-lined casing around the
collision point and be absorbed via capillary action. Additionally, when the plane enters
a 2-g climb, any free-floating liquid inside the collision cage will fall into a Chemical
Pillow at the bottom of the chamber. This absorption pillow was tested with 300 cc’s of
liquid (approximately 20 times the total amount of liquid that will be used on a given
flight day) and it absorbed the liquid completely, without becoming saturated, and
without “loosing” the absorbed liquid when squeezed or subjected to approximately 4g of
acceleration.
When the sled is decelerated to a stop, the trial will be complete. Including the
drop detach and the sled acceleration/deceleration, each experimental run should be
completed in less than 10 seconds. The sled is will be returned to the starting position by
the computer.
Once we will exit microgravity and begin the assent for the next drop, the glass
impact plate will be manually advanced to expose a new dry surface for the next trial and
the vacuum compressor will be cycled to adjust the pressure of the chamber. Both of
these steps will only take a few seconds. The drop size will only need to be adjusted on
the digital injector once on each flight day; it will already be set for the first set of flights,
and will need to be changed to the new volume during the flight.
After all data is collected, we will have a collection of side-view images of each
impact. We will conduct post-flight image possessing, including measuring the height of
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splash waves, the duration of the disruptions, the true size of the impact droplet (through
a grid on the back of the vacuum chamber) and the magnitude of liquid rebound, which
are sufficient parameters to verify the validity of the model. Additionally, we will
correlate our data with the temperature, pressure, and speed of the sled, all of which will
be captured to the computer to verify our hypothesis.
I.3.E.3 Additional Considerations
There are a few subtleties that we will consider and resolve prior to the actual
flight. Included is a description of these subtleties as well as the possible resolutions to
eliminate them.
Air Compression inside the chamber
As the sled accelerates towards the water drop, there will be a known non-linear
compression of the residual atmosphere. This can be calculated easily, and the
atmospheric pressure will be adjusted to create the desired local pressure surrounding the
drop impact.
Non-Spherical Drops
Depending on the method used to detach the drops from the injector, the drop may have
some initial oscillation. It is preferable that the collision with the plate occurs when the
drop is spherical. The period of oscillation of the drop shape can be calculated and
compensated for in the procedure[20,21]. We will wait an appropriate amount of time for
the oscillations to die down due to surface tension. This does not pose any significant
problem.
Aircraft vibrations
By properly insulating the base of our structure, no large vibrations should affect the
apparatus. The foam will dampen both high and low frequency vibrations induced by the
aircraft, and the remaining vibration will not affect the experiment. The timescale of
measurement on each drop is 2ms, which is too short for motion from normal aircraft
turbulence to interfere with.
I.3.E.4 Experiment Flight Plan
The following is a tentative flight plan outlining which runs will be used for
calibration, testing, data collection, and outreach. Please note that this is calculated using
ethanol as the working fluid. See appendix for a water based flight plan.
Day 1
Arc #
1
Diameter(mm)
Practice Trial
Flight Plan
Day 2
Pressure(kPa) Arc #
Practice Trial
31
Diameter(mm)
Practice Trial
Pressure(kPa)
Practice Trial
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2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
Practice Trial
3.4
3.4
3.4
3.4
3.4
3.4
3.4
3.4
3.4
3.4
3.4
Practice Trial
6.8
6.8
6.8
6.8
6.8
6.8
6.8
6.8
6.8
6.8
6.8
Extra
Outreach
Outreach
Outreach
Outreach
Practice Trial
37.7
38.6
39.4
40.2
41.1
41.9
42.7
43.6
44.4
45.3
46.1
Practice Trial
50.9
50.0
49.1
48.2
47.2
46.3
45.4
44.4
43.5
42.6
41.7
Extra
Outreach
Outreach
Outreach
Outreach
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
Practice Trial
10.2
10.2
10.2
10.2
10.2
10.2
10.2
10.2
10.2
10.2
10.2
Practice Trial
17
17
17
17
17
17
17
17
17
17
17
Extra
Outreach
Outreach
Outreach
Outreach
Practice Trial
41.6
40.8
40.1
39.3
38.6
37.8
37.0
36.3
35.5
34.8
34.0
Practice Trial
32.2
31.6
31.0
30.5
29.9
29.3
28.7
28.1
27.5
26.9
26.4
Extra
Outreach
Outreach
Outreach
Outreach
1.3.F Analysis of Quantitative/Qualitative Data Collected
During our proposed investigation, we will record high frame rate video of the impact
of drops of various sizes over a range of atmospheric pressures. From this video, we will
be able to observe whether or not splashing occurs for a given drop size and atmospheric
pressure. By analyzing the video for a given drop size over the full range of pressures
tested, we will be able to determine the threshold pressure to within an acceptable level of
error. This will enable us to determine how threshold pressure scales with drop size. If
we find that the current model does not apply to large drops, we will be in a position to
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propose a new model that correctly predicts the behavior of drops over a wider range of
radii.
There are numerous computer applications with which we may analyze the high
frame rate video captured during the experiment. Although we have not yet decided on a
specific software package, it appears as though we will settle on ITT’s IDL package. It
offers numerous features which will prove invaluable during our data analysis. The
package supports a wide variety of input formats, allows for easy data visualization, and
contains a panoply of mathematical and graphing functions.
I.4 Justification for Follow-Up Flight
This is the first proposal submitted by Fairfield University, and the first test of
this phenomenon in microgravity. Thus, this section is not applicable.
I.5. References
[1] CRC Handbook of Chemistry and Physics, 86th Edition.
[2] "Edgerton, Harold E.: falling drop of milk." Online Photograph. Encyclopædia
Britannica Online. 6 Nov. 2006
[3] Field, J.E., M.B. Lesser, J.P. Dear. “Studies of two-dimensional liquid-wedge impact
and their relevance to liquid-drop impact problems.” Proceedings of the Royal
Society of London. (1985)
[4] Fowles, Grant, and George Cassiday. Analytical Mechanics. Seventh ed. Belmont,
CA: n.p., 2005.
[5] Lesser, M.B., “Analytic solutions of liquid-drop impact problems.” Proceedings of
the Royal Society of London. (1980)
[6] López, J. M., et al. "The Orbital Liquid Experiment (OLE)." Unpublished essay.
European Space Agency. Feb. 2002. 27 Oct. 2006
[7] Purvis, R., F. T. Smith. “Droplet impact on water layers: post-impact analysis and
computations.” Philosophical Transactions of the Royal Society A 363 (2005).
[8] Quero, M., et al. "Analysis of Super-cooled Water Droplet Impact on a Thin Water
Layer and Ice Growth." 44th AIAA Aerospace Sciences Meeting and Exhibit.
Reno, NV. 2006.
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[9] Rioboo, R., M. Marengo, C. Tropea. “Time Evolution of Liquid Drop Impact onto
Solid, Dry Surfaces.” Experiments in Fluids 33 (2002).
[10] Robinson, David, et al. “Development of a Device to Deploy Fluid Droplets in
Microgravity.” NASA Lewis Research Center. 1997.
[11]
Schroeder, Daniel. An Introduction to Thermal Physics. N.p.: Addison Wesley
Longman, 2000.
[12]
Stow, C. D., M. G. Hadfield. “An Experimental Investigation of Fluid Flow
Resulting from the Impact of a Water Drop with an Unyielding Dry Surface.”
Proceedings of the Royal Society of London 373 (1981).
[13] Suryo, Ronald and Osman A. Basaran. "Dripping of a Liquid from a Tube in the
Absence of Gravity." Physical Review Letters (2006)
[14] Thoroddsen, S. T., J. Sakakibara. “Evolution of the fingering pattern of an impacting
drop.” Physics of Fluids 10 (1998).
[15] Suryo, Ronald and Osman A. Basaran. "Dripping of a Liquid from a Tube in the
Absence of Gravity." Physical Review Letters (2006)
[16] Worthington, A. M. “On the Forms Assumed by Drops of Liquids Falling Vertically
on a Horizontal Plate.” Proceedings of the Royal Society of London 25 (18761877).
[17] Thoroddsen, S. T., J. Sakakibara. “Evolution of the fingering pattern of an impacting
drop.” Physics of Fluids 10 (1998).
[18] Woodward, Roger. “Surface Tension Measurements Using the Drop Shape Method ”
2001. First Ten Angstroms.
[19] Xu, Lei. Personal correspondence. Oct/Nov 2006.
[20] Xu, Lei, Loreto Barcos, Sidney R. Nagel. “Splashing of liquids: interplay of
surrounding gas and surface roughness.” Unpublished essay. August 7, 2006. 27
Oct. 2006
[21] Xu, Lei, Wendy W. Zhang, and Sidney R. Nagel. "Drop Splashing on a Dry Smooth
Surface." Physical Review Letters 94 (2005).
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[22] Yarin, A. L., D. A. Weiss. “Impact of Drops on Solid Surfaces: Self-Similar
Capillary Waves, and Splashing as a New Type of Kinematic Discontinuity.”
Journal of Fluid Mechanics 283 (1995).
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II. Safety
II.1 Flight Manifest
Role
Flyers:
Name
Stupak, John
Hermalyn, Brendan
Zaffetti, Michael
Kurose, Jessica
Previous Experience
No previous program experience
Alternate Flyer:
Hunter, Brittany
II.2 Experiment Description/Background
The Fairfield Drop Team is conducting an experiment to better understand the
dependence of splashing on drop size. Under standard earth gravity, there is a maximum
drop size which can be tested(≈4mm diameter). Beyond this limit, as the drop forms on
the injector, gravity eventually overpowers the adhesive force between the injector and
drop, thereby pulling the drop off the injector prematurely. This problem is alleviated in
microgravity. We will be able to test drops up to 17mm in diameter.
Again, it should be said that we will be using a modification of an already proven
apparatus to test drop impacts in microgravity. We have full confidence that our
experimental set up will allow us to capture the data we need to support our hypothesis.
We propose to test 4 large drop sizes. For each drop size we will perform 11 tests at
various atmospheric pressures. Below a certain pressure, namely, the threshold pressure,
splashing ceases to occur. A high frame rate video camera will capture the impact and
subsequent splashing(or lack thereof). From ground based work we have expected values
for the threshold pressure of each drop size. The 11 tests for each drop size will cover
±10% of the expected threshold pressure. If the predicted values are erroneous, they
should still fall within ±10% of the expected values. In this way we will be able to
determine the dependence of threshold pressure on drop size. An experiment of this
nature will yield the most accurate results attainable.
This experiment has not flown prior to the current program. This is not a re-flight.
II.3 Equipment Description
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The following diagrams identify the equipment used for our experimental apparatus. The
models are conceptual, although they are drawn to scale, and are based on proven
experimental methods used for similar research.
Figure II.3.1 This is Figure I.3.D.1 reprinted.
Components are described by number below. An alternate view of the 3D model is
provided:
Figure II.3.2. A top view of the model of the apparatus.
Onboard Computer System (#1)
We will have a personal computer with a serial port, running custom software that will
orchestrate the timing of the various components, including the drive shaft and the
camera. The computer does not move during the trials – it is mounted to the apparatus on
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the outside of the cover. The purpose of the computer is data storage and experiment
timing.
The computer will be custom built for this project with a high-speed, solid-state 3.5”
hard-drive, with a storage capacity of roughly 12 GB. This primary hard-drive is the
cache drive that will receive the stream of image data from the
camera. A daemon (or other script) running on the system will
move the data from the solid-state hard-drive to a secondary
repository hard-drive, whenever the cache drive is idle. The
secondary hard-drive is a standard 7200RPM hard-drive with
over 100GB of storage space. The storage capacity needed is
not significant; over a 2ms recording interval, our camera will
capture from 8 to 32 frames, depending on the operation speed
we decide to use. Each frame is uncompressed and requires
approximately 1 MB of space. On either given flight day, no
more than 1GB of data should be collected. The emphasis of
the computer system is the fast capturing of the data from the
camera controller to prevent stalls in the frame-rate.
Belt Drive-Shaft (#2, 3)
The belt provides the accelerating force to create our collision by moving the plate
mounted on the sled to collide with the drop.
The belt-drive linear actuator offers axial thrust from 240 N (54 lbs.) to 2,490 N (560
lbs.). The carrier section is constructed out of anodized, torque-resistant, extruded
aluminum. Travel speeds of up to 5 M/sec. (16 ft./sec.) with repeatable accuracy to
within ± 0.2 mm (0.008 in.) at 2,000 mm (78.74 in.). PLC-interface utilized for computer
interfacing.
The belt shaft is housed inside the aluminum cover and closed at all times during
operation. The equipment is rated for load and speed performance almost twice as high
as our intended use.
High-Speed Digital Camera (#4, #5)
A digital camera capable of capturing at least 4000 frames / second, to resolve steps
smaller than 0.25ms, is mounted on the sled outside the vacuum chamber, and focused on
the impact surface where the drop will hit. This equipment will be rented, and is rated for
high acceleration – it is the same equipment used in car crash video recording which is
subjected to considerably more g loads than anything we will be working with.
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Digital Vacuum Compressor (#6)
A compressor that can compress a vacuum chamber based on
digital input; range needed is standard atmosphere to roughly 1/4th
standard atmosphere (26kPa). There will be a filter on the
compressor to absorb any evaporated ethanol and prevent it from
leaving the system.
Power Supply (#7)
This is the unit that must receive power from the aircraft, and it divides power into
sockets for the other devices to connect to. All power output is 115V 60Hz.
Impact Apparatus (#8)
We are testing two different methods for the impact apparatus on the ground, and will use
the one that is most efficient. The requirements for the experiment are that for each trial
we have a dry flat surface to hit our drops with; we do not want to open the vacuum
chamber between trials for a number of reasons, so the device must be self-contained.
One solution is to have the drops collide with a thin glass plate, like a microscope
slide. A number of these plates will be positioned around the end of a large thin disk.
After each trial, the disk is rotated a fixed number of degrees to reveal a new, dry, impact
surface for the next trial. Again a combination of sponges and absorbent materials would
contain fluids that escaped the surface, and those that didn’t would be advanced through
sponge-rollers and absorbed.
An alternative is to have a roll of thin plastic material stretched over a slightly
cylindrical metal surface. The film is drawn by an electric motor, and locked in place by
a ratchet on a solenoid. During a test run, all components are still, and are not released
until the sled is stationary. The impact surface would be surrounded by a Plexiglas cage,
lined with sponges except for a view port for the camera. This cage would also have a
small opening large enough for drops up to 17mm diameter to pass without touching the
sides. The material is pulled over a slightly curved surface to ensure firm contact with
the surface, and ensure no air can get underneath the film. The cage will catch any liquid
that escapes the surface during deceleration of the sled, and prevents the other
components from getting wet. The film would be mounted on rollers that slide past a
sponge so that after a trial, the roller can advance the tape to a dry surface and the
experiment can be repeated without breaking the vacuum seal.
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No components inside the vacuum chamber are ethanol sensitive, and the involved
quantities of ethanol over the course of a flight are not substantial enough to pose any
dangers. This will not, of course, be a consideration if water is used.
An important consideration to make sure the impact apparatus is able to advance
to a dry surface after each trial is how much the drop will spread out after impact.
Creating chambers on the impact surface would confine the spread to a fixed region;
however, the introduction of barriers in this manner will cause secondary waves to reflect
back from the walls, and interfere with the splash. To avoid the complications associated
with that, we would like the drops to extend as far as possible. Based on ground
experiments, a drop of ethanol will spread on glass until it has as resting depth of 1mm
(on the average). Therefore given our largest drop size of diameter d = 17mm:
4 d 2
"( )
3 2
1
V = " (0.017) 2
3
V = 2.57x10#6 m 3
V=
!
This same volume can be expected to spread into a cylinder with a height of 1mm and a
diameter D of:
D
V = " ( )2 h
2
thus
4V
2.57
=2
h"
"
3
D = 0.0573m = 57.3mm 3
D=
In the general case, we can determine that:
!
4 d 3
D
" ( ) = " ( )2 h
3 2
2
d 6d
3
D=
= 25.819 # d 2
3 h
We have tabulated the expected spread for our drop sizes in ethanol:
!
Drop Size (diameter)
3.4 mm
6.8 mm
10.2 mm
17 mm
Expected Spread (diameter)
5.11 mm
14.5 mm
26.6 mm
57.2 mm
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To give some tolerance on these estimated calculations, the impact plate allocates an area
of at least 30% more than the expected spread. On the first flight day, that means a
20mm diameter impact surface, and on the second flight day that requires a 80mm
diameter for each trial. Walls are places at the 80mm mark; should the spread be
significantly higher than found on ground trials, reflected waves would have to travel 15
centimeters before returning to the original impact site. Even if this occurs, the amplitude
of returning waves after that distance would be highly damped, and the time it would take
them to arrive back will be outside of our observation window.
Safety Cover (#9)
All moving parts are contained inside an aluminum container with a Plexiglas access
panel on the top. The access panel has a key-lock that will be secured before, and remain
secured during, each trial. The panel will only be opened when the device is not running.
The cover it to prevent accidental contact with moving parts when the apparatus is in
operation.
Vacuum Chamber (#10)
The vacuum chamber is either a reinforced glass chamber, or a ceramic chamber
approximately 6”x6”x12”. Also contained in the chamber is the digital injector. This
chamber provides our controlled-pressure environment. The chamber and all equipment
inside are rated to below 1kPa, but we will not go below 26kPa for this experiment. We
will also not be experimenting with any high-pressure environments; the maximum
pressure will be standard atmospheric pressure.
Digital Variable Injector (#12)
A Teflon-tipped needle injector mounted firmly at the top of the vacuum chamber. The
injector can create drops of specified sizes (specified digitally in cubic-centimeters),
specifically sizes (ethanol):
Size (CC)
0.121
0.484
1.09
3.03
Diameter (mm)
3.4
6.8
10.2
17
Scale
1x
2x
3x
5x
Tolerance (CC)
0.001
0.001
0.01
0.01
The injector device has no moving parts, and can sustain the intended accelerations.
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Aluminum Structure
The frame for the apparatus is constructed out of hollowed aluminum for durability and
strength. The entire apparatus will be bolted to the floor at the ends. The drive shaft is
going to accelerate a 45 pound (this is the maximum figure we are considering – our
expected weight is 30% less) sled at 22.12 ms which will provide a considerable torque on
the shaft. The center of mass of the sled sits about 4 inches (10.16cm) out from the drive
shaft belt so on the initial launch, this will produce a torque:
!
"=F#r
" = (452.1N)(0.1016)cos(90)
" = 45.93kg
!
This is not a substantial force if the device is properly bolted to the floor. The shear
stress involved is far below the critical limit of standard bolts.
Shock-Insulating Base
The base is comprised of two metal sheets sandwiching high-density foam padding, with
high and low frequency dampening. Vibrations of the aircraft in any direction will be
minimized with the padding. Also, given the time interval of the experiment, even
moderate vibrations should have little effect.
Inertial Sled
The sled is a metal plate firmly mounted to the belt on the drive shaft. Mounted on the
sled are a vacuum chamber, a digital high-speed camera, and a small mirror and lens
apparatus positioned to focus the camera properly. All equipment firmly attached to the
sled and well below the load rating on the sled.
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II.4 Structural Design
The material under consideration for the base is Aluminum which weighs 0.356 pounds /
linear foot. For the amount of aluminum needed for various frame components, the
estimated weight is about 12 pounds. The drive track and controller together weigh
approximately 40 pounds. The camera head weighs 2.2 pounds, and its controller weighs
12.13 pounds. The vacuum chamber weights around 10 pounds, and the compressor
around 50 pounds. The computer equipment will weigh less than 10 pounds. The
remaining structure will be constructed out of a polycarbonate material (such as Lexan)
and will weigh 18 pounds total. The total estimated weight of the apparatus is around
200 pounds, well under the maximum weight limit.
II.5 Electrical System
The computer equipment, as well as the digital injector and vacuum compressor, have
electrical requirements of 115V 60Hz. These systems do not require any custom power
wiring; they only need to be plugged in. Power is required throughout the flight both
during and in between trials.
The only custom wiring will be the connectivity between the computer and the camera,
and the computer and the PLC controller on the linear drive shaft. The platform is
stationary at all times, so the COM port wires between the shaft and the computer will be
unmoving and fixed out of the way of moving equipment. The wires connected between
the camera and the camera PCI controller on the computer will need to move. They are
fixed on the computer end, but must ride with the sled on the camera end.
To achieve this, these wires are guided to a position about 18” above the sled, without
coming near the path of motion for the sled. Centered over the drive shaft, the wires now
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connect to the camera from above. The motion of the sled is 48” total, or 24” to either
side of the axis where the wires are attached to the top. From this height, the motion of
the wires to follow the sled is not substantial. Furthermore, the required length of the
wires from the fixed position centered at the top is 30 inches; the most slack that the wire
will experience is at the halfway point for the sled, where there will be 12 inches of slack
in the wire. 12 inches total allows an additional hang of 6 inches down (and the other six
back up), which is not enough to come into contact with any stationary parts while in
motion, nor to drag on the track while the sled is moving. The wires will trail from the
back of the sled, but even if they were to come off the front, the slack would not be
enough at its maximum to catch under the sled while it moved. Lastly, the adaptor that
plugs into the back of the camera does not need to screw in. If we leave the plug
unscrewed, then should it catch something in an unforeseen circumstance, the plug will
simply pull out and no damage will be done the experiment or the equipment.
II.6 Pressure/Vacuum System
This experiment relies on a plastic vacuum chamber that will be de-pressurized to
varying pressures, no lower than 10 kPa, and no higher than standard atmospheric
pressure. Initial trials will start close to standard pressure, and successive trials will
decrease the internal pressure incrementally. When the trials are complete for a given
day, the vacuum compressor can restore normal pressure in a very controlled manner.
The pressures involved are not particularly drastic, and do not change rapidly or
explosively at any point in the experiment. Similar vacuum chambers are capable of
supporting vacuums 10 times more powerful; i.e. 100 Pa, or more. Thus the pressures
used in the experiment are well within the operational limits of the chamber. We will be
using a digitally controlled vacuum pump to control the pressure in the chamber. We
anticipate that this will be controlled via computer. The vacuum pump will be cycled on
only when needed, and will operate over a range of ±10% of the calculated threshold
pressure for each droplet size. This requires an accuracy of approximately 0.1 kPa. Most
digitally controlled vacuum pumps are accurate in increments of 50 Pa or better, and thus
this will not pose a problem.
The vacuum chamber will be pressure tested in the lab down to at least 100 Pa to
ensure there will be no leaks. We will be mounting a fluid trap inline with the filter to
ensure that none of the vaporized liquids escape into the cabin of the airplane, as well as a
preventive measure to prevent fouling the pump. We also have the option of dumping
removed air out the gas evacuation tubing on the DC-9. Since
II.7 Laser System
No lasers contained in this experiment.
II.8 Crew Assistance Requirements
No special duties will be required of the Flight Crew.
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II.9 Institutional Review Board
No human, animal, or other biological substances are involved in this experiment.
Therefore, the services of the Institutional Review Board will not be necessary.
II.10 Hazard Analysis
1. Structural Failure
Description: The frame of the experiment bends or breaks
Causes: Severe g-loads on board the DC-9; excessive vibration
Results: Components of experiment move freely about the cabin.
Safety Precautions: All components of the experiment will be bolted
securely to the base plate; each bolt will be secured with a thread locking
substance. The base plate mounted on a layer of foam to reduce
vibrations. Additionally, the frame of the experiment (as well as the
interior parts) will be built to withstand approximately 6g of acceleration,
which is well beyond the maximum 3g that the DC-9 is capable of. All of
the moving parts of the experiment are enclosed inside a Lexan chamber
for safety.
2. Sled Detachment
Description: The vacuum chamber or parts inside become detached from
the sled during or between loops.
Causes: Force of linear drive, failure of attachment devices, breaking of
attachment points
Results: Components are no longer connected to linear drive.
Safety Precautions: As the linear drive accelerates with a fair degree of
force, we have designed the vacuum chamber assembly with a high factor
of safety. The Plexiglas chamber is cocooned and supported by a steel
plate, which is bolted to the linear drive sled. This puts the force of the
accelerations on the plate, and not the Plexiglas; the metal has a much
higher shear strength. The only moving part inside the vacuum chamber is
the impact surface, which rotates to allow each drop to impinge upon a dry
glass surface. All glass will be mounted with epoxy. All components of
the experiment will be mounted and bench tested to 15g prior to flight. In
addition, the large acceleration is in the same direction as the glue acts; i.e.
the initial yank pulls the glass onto its substrate rather then away from it.
The acceleration to slow the chamber is much less then the initial pull to
release the drop and impact the drop on the surface. In case there is a
failure, however, the chamber and pieces will be moving ballistically
unattached. The Lexan cover for the moving portion of the apparatus will
contain the parts, and not allow them to simply float around inside the
cabin. In addition, the side of the box that the linear drive will accelerate
the apparatus towards will be constructed out of sheet steel rather than
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Lexan to ensure that even if the parts do impact that surface, they will not
be able to break through the containment box and escape into the cabin.
3. Electrical Failure
Description: Short circuit, overload, or faulty ground
Causes: Forces and vibration on DC-9 sufficient to break or disconnect
wires, fluid leak
Results: Experiment powers down
Safety Precautions: Circuit breakers will be installed in the power
supply in case there is an electrical fault. All fluids are in a closed system;
the only possible way to have a fluid contact an electrical component is if
that system leaks (see below). As soon as any device experiences a fault,
the circuit breaker will cut off power to that device. A thin rubber mat
will be placed between the electrical components (such as the vacuum
pump and camera box) and the base plate, which will reduce transmitted
vibration and also insulate the devices from the metallic base plate.
4. Fluid Containment Failure
Description: The closed fluid system leaks
Causes: Excessive vibration, hose rupture, containment vessel(s) crack
Results: The test fluid leaks onto moving parts, electrical devices, and
viewing surfaces.
Safety Precautions: All hoses will be securely clamped, and rechecked
before each flight. The tubing used in the experimental setup have a
minimum burst rating of 300 psi, three orders of magnitude larger then the
pressures we expect. We have designed a nested box arrangement for our
clear containment boxes so that even if one should crack (although this is
highly unlikely; see #1 above) the next box will catch any spilled liquid
without it leaking into the cabin of the aircraft. We will also be lining the
bottom of the vacuum chamber and containment chamber with desiccant
bags to absorb the used drop liquid in the chamber, and to ensure all leaks
are contained. In addition, none of the liquids we are considering are
corrosive, and will not present a problem. The linear drive is fairly
immune to liquids along its length; only the electrical motor at the end of
it is susceptible.
If liquid does come in contact with any electrical
components, the experiment will be shut down and we will use wipes to
absorb all moisture before continuing the experiment.
5. Syringe Failure
Description: The syringe comes off of the apparatus, or breaks
Causes: Excessive vibration, sharp acceleration
Results: Syringe and possibly needle are free to move.
Safety Precautions: We are using a digital syringe to allow for not only
more accurate droplet size formation, but also for more robust design. A
digital syringe, which has the reservoir inside a plastic container, is much
less prone to breaking then, say, a high-end glass syringe. Our design has
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the needle apparatus inside the vacuum chamber, and thus not prone to
breaking. We will construct a bracket around the syringe to minimize
shear stress on the connection point. Additionally, we will tether the
syringe to the apparatus in case of failure so that it does not freely move
about inside the containment area.
6. Optical Obscuration
Description: Test liquid is incident upon the optical glass in the vacuum
chamber, obscuring the view of the camera lens.
Causes: Sudden, sharp change of altitude and position of DC-9, splashing
of droplet
Results: Camera cannot focus on drop impact area
Safety Precautions: Although not a safety concern per se, we will address
this issue here as it is integral to the functioning of our experiment.
Because the time between drop release and impact is so short, it would
require a vertical acceleration several times larger than the DC-9 is
designed to attain in order to appreciably divert the droplet. We have
designed the chamber in such a way that the optical glass is many times
further away from the droplet impact then we calculate the splash will
propagate. The position of the optical glass also implies that the camera,
which will be focused further into the chamber, will simply not see a very
small amount of liquid on it. In the very unlikely event that fluids do
come in contact with the optical glass, we have devised a procedure to
clean it. First, the 1.8g pullout from the microgravity environment will
cause all fluids to migrate towards the bottom of the vacuum chamber,
which is lined in desiccant bags. If that is not sufficient to pull the liquid
off the optical glass, we will power down the experiment, open the access
hatch to the drive bay, depressurize the vacuum chamber, open the top,
and wipe the glass with a chem. wipe. The process will then be reversed,
closing the vacuum chamber, resealing the hatch, and powering up the
experiment again. The vacuum pump will be cycled on and the chamber
will be returned to vacuum. We estimate this whole process, a last resort,
will take no more then 3 minutes.
II.11 Tool Requirements
We will bring all of the tools we need to assemble our apparatus at the Johnson
Space Center with us, including ratchets, screwdrivers, and pliers. We do not require
any tools to operate the experiment on board the DC-9; however, we would like to bring
a flathead screwdriver and needle nose pliers with us during the flight in case we need to
make an adjustment in the vacuum chamber.
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II.12 Ground Support Requirements
We will require a 115V power supply in order to test our electrical and data
acquisition systems.
II.13 Hazardous Materials
We are still considering a few different liquids for our tests. Ethanol is the liquid
used in the University of Chicago tests. It will wet the substrate and eliminate any
chance of retraction and rebound of the drop. It also has a low surface tension, which is
desirable for our experiment. Only small quantities of Ethanol will be needed onboard.
The liquid system will be closed to prevent Ethanol from becoming airborne, and a fluid
trap will be installed in the vacuum pump to ensure that no aerosol ethanol makes its way
back into the cabin.
We are also considering distilled water as a possible alternative. Water is
favorable as it is not hazardous, but its’ different surface tension will change the
parameters of the experiment somewhat. Neither the model nor our experimental setup
are liquid specific, however, and either should work. We will conduct ground-based
testing to determine which liquid will work best, and are open to the suggestions of
NASA specialists in deciding which will be used.
II.14 Procedures
II.14.1 Ground Operations
Prior to shipping our experiment to the JSC, we will bench test all structural
components to a minimum of 6g on each axis, and 15g dynamic stress for all moving
parts. We will conduct ground based testing using our apparatus to ensure everything
will function smoothly during the flight.
Upon arrival in Houston, we will carefully inspect all components for damage
during shipping as we reassemble our experiment. Any necessary repairs will be made.
We will conduct a few tests of the equipment to make sure all is working correctly before
securing it in the DC-9. Our base plate design was engineered to be bolted to the floor of
the DC-9, it can also be strapped, based upon the NASA specialists’ advice.
II.14.2 Pre-Flight Operations
The surface of the glass impact plate will be cleaned thoroughly and insured to be
dry. The fluid reservoir will be filled, and fresh desiccant bags will be secured in the
vacuum chamber. The chamber will then be closed and vacuum tested to ensure it is
sealed. All cables and hoses will be double checked for positive connection and free
movement with the sled. The camera will be cycled on and reviewed to ensure the drop
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impact zone is in focus. All other electronics will be turned on and checked to make sure
they are operating normally, including a test of the drive controller to verify the belt is
not caught, and that the motor can move the sled forwards and backwards. The camera
will be reset, and its on-board memory will be cleared.
Once satisfied that all portions of the experiment are in working order, the
protective cover will be closed and latched into position, safely encasing all moving parts
of the experiment.
II.14.3 In-Flight Operations
Once we are at altitude, all electronics will be switched on. At the start of the
microgravity portion of the parabolic loop, we will begin production of a droplet on the
injector needle with the digital syringe. Once the full drop size has been reached (under 3
seconds), we will signal the experimental cycle by starting the computer program. The
linear drive belt will accelerate briefly to detach the drop from the injector needle. After
detachment, the belt will pause briefly to allow the droplet to stabilize into a sphere. As a
guide, 1cc of water (the average size of our drops) will stabilize in approximately 100 ms.
After the drop stabilizes into a sphere, the belt drive will move the vacuum chamber at 3
m/s causing the formed droplet to impact upon the glass plate. During this process (under
a second), the computer will cycle the camera on in time to capture the impact. After the
impact it will then bounce the recorded video to the hard drive for future retrieval. The
drive belt will slowly accelerate to a stop after impact. The glass impact disk will be
rotated to reveal a clean dry surface, and the desiccant will absorb the excess liquid. The
linear drive belt will be returned to the starting position. The pressure will then be
adjusted electronically as per the flight plan, and the experiment will then be ready for
another test. We plan to conduct 11 trials for each of four drop sizes, each trial at a
different pressure, allowing us to determine the threshold pressure for each drop size to
an accuracy of no less then 1%.
After we have gathered our experimental data, we will conduct the outreach portion
of our program, as is built into the flight plan. These projects will be conducted inside
the “outreach box,” a small Lexan glove box with a standard video camera that will allow
us to test and videotape the experiments brought onboard without risk of them escaping
into the cabin.
II.14.4 Post-Flight Operations
After the 30 parabolic loops, the linear drive will be returned to starting position,
and all electronics will be powered down. Upon landing, the vacuum chamber will be
opened, and the desiccant bags disposed of. The glass impact plate will be dried and
cleaned; any extraneous splashes in the chamber will be wiped up. Any remaining fluid
in the reservoir will be drained. The video taken during the flight will be backed up on
an external hard drive.
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III Outreach Plan.
III.1. Objective
We have three main goals for our outreach program:
1) Inspire interest in the physical sciences through classes, demonstrations, and
hands on activities.
2) Educate the general public about our project.
3) Enlighten students and teachers about the many opportunities NASA has to
offer.
III.2 Website
http://students.fairfield.edu/physicsclub/microgravity
We have designed a website that will not only inform the public about our
proposal, but serve as a hub for our outreach program. Through the website, students and
teacher will be able to keep track of our status through crew journals, participate in online
polls regarding their own outreach agenda (as outlined below), complete science quizzes
of the week to compete for prizes, and access valuable links in the sciences and at NASA.
Figure III.2.1. http://students.fairfield.edu/physicsclub/microgravity
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III.3 Partnerships
In our efforts to reach the widest audience possible, we have teamed up with
several institutions.
III.3.A.The Discovery Museum
4450 Park Ave, Bridgeport, CT 06604.
(203) 372-3521
The Discovery Museum is a not for profit science and technology museum with a
strong focus on education. Each year, The Discovery Museum draws over 100,000
visitors and teaches almost 70,000 students of all ages on a variety of subjects, ranging
from rocketry to submarine science. They have the only Challenger Learning Center in
Connecticut, a program that takes students on a simulated space mission in honor of the
planned educational mission of the final Challenger flight. By tapping into the programs
and resources at The Discovery Museum, we will be able to reach a wide range of
children at a variety of different grade and ability levels. Many of the programs at the
museum are tailored for underprivileged students from inner city Bridgeport, (the town
next to Fairfield), and the surrounding areas, while other interdistrict programs bring
urban and suburban students together under the common goal of learning science while
breaking down socioeconomic barriers. In addition, the museum’s membership and
school base will allow us to easily distribute our outreach plans, and develop and present
our programs to a varied and interested audience through a respected institution that is a
staple of the community.
III.3.B Bridgeport School District
45 Lyon Terrace, Bridgeport, CT 06604
(203) 576-7146
We have also partnered up with the Bridgeport School District. While initially ,
we were going to simply contact each school on a case by case basis, teaming with the
district itself provides access to a far greater number of students, and an ability to
highlight the areas where we will do the most good. The second largest district in
Connecticut, it contains 30 elementary schools, three high schools, two alternative
programs, and an inter-district vocational aquaculture school; serving a total of 23,000
students. The vast majority of these students are members of minorities, and are
underrepresented in the sciences. Obviously, we cannot hope to reach all of these
students, but we hope to visit as many of the classes as possible; we estimate that number
will be between 7 and 8 classes for multiple visits, and possibly a few multiclass
assembly presentations and demonstrations. Science to many of these students is a
foreign idea, something that they can never be a part of; the teachers do their best to
educate their students, but have a difficult time inspiring interest when they are restricted
to text books. By teaming up with the Bridgeport School District, we hope to not only
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supply new ways of teaching science, but provide gripping new learning experiences that
will motivate the students and teachers alike.
III.3.B Fairfield High Schools
Fairfield Warde High School
755 Melville Ave, Fairfield, CT 06825
(203) 255-8449
Fairfield Ludlow High School
785 Unquowa Road, Fairfield, CT 06824
(203) 255-7200
To expand our outreach program to the high school level, we have partnered with
two high schools in Fairfield Connecticut, near the university campus, Fairfield Warde
and Fairfield Ludlow. These schools have very strong science and physics programs, and
will give us the opportunity to go more in depth into the physics of our project, as well as
the processes of coming up with an experiment and methods for testing it. They are also
an excellent outlet for NASA education, as they have the talent and backing to partake in
many of the more competitive programs NASA has to offer. We expect to reach
approximately 40 students per school for a total of 80 students.
III.4 Target Audience
We plan to connect to the community on four levels:
1.
2.
3.
4.
Middle School Students (Grades 5-8)
High School Students (Grades 9-12)
College Students
The general public
We will address the lower elementary grades through presentations to the teachers
and presentations. We feel that it would not be realistic to expand our outreach to cover
even more grades and classes, and our subject material has much more relevance to the
curriculum guidelines of the middle and high school levels then it does for the elementary
level.
The first two of these categories will be served through our work at The Discovery
Museum and outreach at the Bridgeport Public Schools. One of the reasons we picked
these institutions is because we will be dealing with predominantly minority students who
are underrepresented in the sciences. This gives us a unique opportunity to truly change
the path of some lives through our outreach.
Bridgeport School District Census
Total Population under 18:
Hispanic or Latino:
39,672
16,216
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Non Hispanic or Latino:
23,456
Population of one race:
White alone:
Black or African American alone:
American Indian or Alaska Native alone:
Asian alone:
Hawaiian or other Pacific Islander alone:
Some other race alone:
Population of two or more races:
36,814
12,699
14,935
214
1,192
62
7,712
2,858
Percent of Minority Students:
67.99%
Table III.1. Census Data for the Bridgeport School District, 2000. Taken from the
National Center for Education Statistics.
Census Data on Select Bridgeport High Schools
School
Grades Students % White % Black % Hisp. % Asian % Indian
Bassick High School
9-12
947
10.9
45.8
39
4.3
0
Central High School
9-12
2,171
19.7
41.5
32.9
5.6
0.2
Harding High School
9-12
1,352
3
43.7
52
1.3
0
Homebound
PK-12
58
10.3
46.6
43.1
0
0
Table III.2. Census Data for Bridgeport High Schools, 2000. Taken from the National
Center for Education Statistics.
We will reach college students through our activities with the Fairfield University
chapter of the Society of Physics Students, and will reach the general public through
exhibitions at The Discovery Museum and open lectures at Fairfield University.
III.5 Connection to Curriculum
In planning our activities and presentations to the middle and high school classes,
we have looked to the “Core Science Curriculum Framework: An Invitation for Students
and Teacher to Explore Science and Its Role In Society” guidelines issued by the
Connecticut Department of Education. The following table summarizes a few of the
Content standards that we will address by grade.
Content Standard
Grade 5
5.3
5.4
Grade 6
6.1
Summary
Regular and predictable motion of solar system objects
Using tools to acquire new information; telescopes, magnifiers.
Basic Chemistry, introductory fluid dynamics
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6.3
Grade 7
7.2
7.4
Grade 8
8.1
8.3
Grade 9
9.3
Effect of Sun’s energy upon Earth
Human biological systems; challenges of habitation in space
Technology of Food Production; astronaut food
Inertia, forces
Gravity
Fuels
9.4
Atomic reactions
Grade 10
10.5
Origins of life, cosmic seeding
10.6
Living environments
Table III.3. Curriculum standards outlined by the Connecticut Department of Education.
Each of our classes and presentations will incorporate many of these standards,
while being tailored to the individual class or classes at hand.
III.6 Activities
We have divided our activities into two sections.
III.6.A
Middle School and High School
We have planned six major projects with The Discovery Museum and the Bridgeport
Public Schools.
1. Space Science for the Bridgeport Talented And Gifted (TAG) program, grades 58. We will be conducting outreach into these inner city schools, supplementing
the curriculum with demonstrations and presentations, tailored to grade level and
content standards in the sciences. These students represent the top of the
spectrum in the schools, and thus we will be challenging them the most with
design projects, and hard questions. We will also emphasize pursuing other
NASA opportunities, both in their current educational level, and as they continue
through high school and college. Although we will work with the teachers of the
classes to develop exactly what material we will cover, we anticipate
demonstrating or presenting the following topics and asking the following
questions:
• Gravity/Microgravity
i. What makes gravity?
ii. How does gravity affect us?
iii. Does gravity “pull” more on heavier objects?
iv. Do all objects fall at different speeds?
• Introductory astronomy
i. Heliocentric model of solar system
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•
•
•
ii. What clues are there for this model?
iii. Why do planets circle the sun instead of flying off?
iv. Sun’s impact on Earth
Forces and inertia
i. How do we see forces and inertia in every day life?
ii. Will these forces exist in space?
iii. What is mechanical advantage?
iv. Examples and demonstrations
Chemistry and fluid phenomena
i. What makes something a liquid? Solid? Gas?
ii. Can things change form?
iii. Mixtures, solutions, and reactions.
iv. Where do we see applications of these in every day life?
Biology
i. Differences in environment between earth and space
ii. How can we live in space?
iii. Challenges of long distance space flight
iv. Human colonization of other spatial bodies.
2. Outreach And After School Programs at Bridgeport Public Schools, grades 5 -8.
These programs will be on a smaller scale of one or two classes per group. Each
segment will be geared toward a specific curriculum goal, as outlined above, and
will provide us with an opportunity to provide real hands on learning experiences
to this children. In addition to some of the topics listed above, we will emphasize
space science, including rocketry, astronomy, environment, and the planets. With
these small groups, we will try to develop their interest over a few meetings each
group (approximately 2 or 3), culminating in a school wide science fair.
3. Development Of A New Gravity Learning Lab at The Discovery Museum, grades
5-8. For this section, we will bring a set of four experiments up with us on board
the C-9, conduct and record them during the outreach portion of our flights, and
bring our results back with us to Connecticut. Students will perform these same
experiments on earth under normal gravity conditions, and will make predictions
as to what will actually happen in microgravity. We will then be able to show the
video of these experiments, confirming the expected results of the students. This
particular section of the outreach portion has implications not only with the
current grade levels of students, but also far into the future. It is a very unique
opportunity to allow students to see their predictions come alive in a very real
sense. The actual experiments conducted will be selected from a pool of
possibilities by a poll on our website, which each student and teacher in the class
will be allowed to vote on. This will personalize the experience even further, and
also draws in the technological literacy component often absent in the curriculum.
Possible experiments include: gyroscopes, (self contained) capillary tubes, and
friction. Other experiment ideas will be gathered from teachers. Depending on
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teacher and student interest, we will also investigate a competition among the
schools to bring a small student designed and constructed test onboard for one of
the outreach portions.
4. Collaboration with TEAMS: Totally Extreme Adventures in Math and Science,
5th grade. This is an interdistrict program that pairs 350 students from urban and
suburban schools with the common interest of learning science through space
applications. We would provide the gravity section of the curriculum to these
students, with the goal of preparing them for their final project of constructing a
simulated moon base.
5. Development of a “drop tower” apparatus that will allow students to see what
happens in “microgravity” through the implementation of a box containing a
camera, light, and student-built experiment that will be dropped from the roof of
the Museum along a rail into a container of packing peanuts. This should allow
for a few seconds of microgravity, and can be a resource used by science classes
all over the area. This project is dependant upon funding provided by a grant we
will apply for if accepted.
III.6.B
High School
We will connect with inner-city Bridgeport high schools through the Discovery
Museum public presentations. Through these, we hope to educate the students about the
wonders of physics, and spark interest in the sciences.
Our main work at the high school level, however, will be with the Fairfield high
schools. Because of the much smaller class sizes and higher level of education, we will
be able to focus much more on the actual physics of space science. Among the projects
we will be working with the teachers to integrate into the curriculum of the schools are:
1) Model Rocketry
2) Drop Tower Tests at The Discovery Museum
3) Microgravity experiment design and construction, possibly to be flown as one of
our outreach trials
4) A Space-Science technology fair to present small team-based research projects to
the entire school.
III.6.C
University and Public
Through the Fairfield University chapter of the Society of Physics
Students, we will be conducting a series of three presentations open to the general
public as well as the student body. Our topics will include 1) Microgravity, and the
benefits of studying phenomena in microgravity; aimed at a non science major level
2) Our project and NASA opportunities for students and faculty; aimed at science
majors 3) The results of our project (upon our return); aimed at both groups. We also
hope to present our results at other SPS schools in the local area, and at conferences
upon the completion of our project.
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III.7 NASA Education
Historically, very few teachers or students from the Bridgeport area have participated
in any NASA programs. When speaking to the teachers, however, the reason for this
becomes apparent- they simply do not know about them. Therefore, we plan to give a
presentation for teachers and administrators on the different NASA opportunities
available for students, educational enrichment, and the educators themselves.
Figure III.1. Example Slides from presentation to teachers and administrators.
We will also construct a portfolio of the different NASA programs available tailored
to grade level which we will distribute one to the science teachers in the district and
beyond through The Discovery Museum. For example, the middle school packet will
include:
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•
•
•
•
A list of learning resources, including information on the NASA Educator
Resource Center Network, and Educational Publications & Products, with ideas of
how to integrate it into the curriculum.
A number of links to the internet and multimedia resources available through
NASA, and methods for integrating them into the classroom.
Listing and descriptions of the NASA Education programs for students, including
the DIME program, SEMAA, MATHCOUNTS, the Great Moonbuggy Race, and
job opportunities, along with suggestions and recommendations from Fairfield
University faculty, and the Fairfield flight team’s own experiences on how to win
these opportunities.
Professional Development opportunities for teachers and administrators. This is
vital, as better teachers result in more inspired students.
This information will all be available through the Education portal of our website as
well, with links and further ideas. Depending on teacher response and grade level, we
may also construct a flyer that will go in a mailing to the parents that outlines the
opportunities for the students.
One of the best ways we can encourage the minds of the next generation is to show
them how many opportunities are available, and allow them to feel the beauty of science
for themselves.
While The Discovery Museum already uses a fair amount of NASA multimedia
and materials, we will work with them to integrate more NASA resources into the
curriculum of their classes, and in their programs for the general public, as well as
displays and inclusion of NASA programs in their mailings.
A modified presentation will be given to the students, teachers, administrators,
and parents of the Fairfield high schools, with particular emphasis placed upon
opportunities for that grade level.
III.8 Press Plan
If our proposal is accepted, we have a press plan that encompasses several media
and should reach a wide audience.
•
•
A press release will be immediately written and submitted to papers in the local
region of Fairfield University, as well as those in the team members’ home towns,
detailing our proposal, our outreach, and NASA’s Reduced Gravity program.
Upon completion of the project, we will submit an additional release regarding
the outcome of the experiment, our experiences with the project, and a reiteration
of the NASA program.
Similar press releases will be submitted to local T.V. and Radio stations, with the
hopes of interviews of the team members.
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•
A scholarly paper will be written upon completion of the project, and sent to
various journals and newsletters, including The Observer, the Society of Physics
Students Newsletter, the AIP, and Physics Letters.
III.9 Milestone Timeline
•
•
•
•
•
•
•
•
•
•
•
•
•
December 14th- Receive notification of proposal status.
Mid December (before winter break) – meet with Discovery Museum Staff
and Director of Science of Bridgeport Public Schools (as well as any available
teachers) to outline course of action; prepare and submit grant proposal for
funding of extra projects through Discovery Museum; submit press releases
Winter Break- Prepare experiments and presentations
Mid January- Begin TAG program meetings and Bridgeport Outreach
meetings on an alternating biweekly schedule. Meet with Fairfield high
schools to plan activities. Present NASA opportunities presentation at high
schools.
Late January- Presentation at Discovery Museum on NASA opportunities, for
educators and administrators
Early February- Open meeting at Fairfield University for first presentation and
discussion. Meeting with Fairfield high schools to talk about our experiment,
and outline first project.
Mid February- Demonstrations at select Bridgeport schools. 2nd project with
Fairfield high schools.
Late February- Gravity portion of TEAMS curriculum; conduct poll for
outreach experiments; 2nd presentation at Fairfield University
March –flight
Early April- Conduct learning lab, complete with video footage of
experiments conducted in microgravity; development of drop tower. Testing
with Fairfield high schools.
Mid April –School Wide Science Fairs; submit scholarly paper of results
Late April- 3rd and final presentation at Fairfield University; conferences and
other SPS school presentations. Rocketry project with Fairfield high schools.
May-culmination of TEAMS program; final presentations at Bridgeport
Schools
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IV. Administrative Requirements:
IV.1 Institutional Letter of Endorsement.
Please refer to Appendix B.
IV.2 Statement of Supervising Faculty
Please refer to Appendix C.
IV. 3 Funding/Budget Statement
Our funding will be provided by Fairfield University. A sizable portion of the
equipment and materials used in our experiment is already at Fairfield, and will be
available for our use at no cost. In addition, we have been in touch with a few local
businesses that have expressed interest in sponsoring part of our experiment, and will
thus reduce the cost to Fairfield. Personal contributions from the team members will also
be used to offset the cost.
Costs for Experiment
Laptop Computer and peripherals
High Speed Camera rental
Vacuum Chamber and Pump
Aluminum and other materials
Linear Drive
Digital Syringe and needles
Assorted hardware
Subtotal:
$2500
$6000
$400
$300
$2000
$400
$500
$12100.00
Travel Expenses
Transportation (Airline Tickets)
Accommodations
Food and Expenses ($30 per person, per day)
Car Rental & gas
Subtotal:
$1500
$900
$1200
$700
$4300.00
Total Cost:
$16400.00
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We have broken down the expenses into two categories: experiment costs, and
travel expenses. The travel expenses are calculated for four people’s airfare and lodging
for ten days in Houston.
IV.4. Experiments Involving Animals
Our experiment does not involve any animals. This section is non applicable.
IV.5 Parental Consent Forms
All members of our team are over eighteen years of age; thus, parental consent
forms are not needed.
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V. Appendices
V.1 Appendix A
It is not absolutely essential that we perform this experiment using ethanol. It is
widely used among those researching drop behavior for numerous reasons. However, we
could perform the same experiment with water if the use of ethanol poses a safety issue.
Water has a higher surface tension than ethanol, so water drops would have to be larger
as compared to ethanol drops. This can be seen in the figure below:
Alternate
Flight Plan
(water)
Day
1
Arc
#
Day 2
Diameter(mm) Pressure(kPa)
Arc # Diameter(mm) Pressure(kPa)
1
Practice Trial
Practice Trial
31
Practice Trial
Practice Trial
2
Practice Trial
Practice Trial
32
Practice Trial
Practice Trial
3
20
71.6
33
40
50.6
4
20
70.3
34
40
49.7
5
20
69.0
35
40
48.8
6
20
67.7
36
40
47.9
7
20
66.4
37
40
46.9
8
20
65.1
38
40
46.0
9
20
63.8
39
40
45.1
10
20
62.5
40
40
44.2
11
20
61.2
41
40
43.3
12
20
59.9
42
40
42.3
13
20
58.6
43
40
41.4
14
Practice Trial
Practice Trial
44
Practice Trial
Practice Trial
15
30
58.5
45
60
41.3
16
30
57.4
46
60
40.6
17
30
56.3
47
60
39.8
18
30
55.3
48
60
39.1
19
30
54.2
49
60
38.3
20
30
53.1
50
60
37.6
21
30
52.1
51
60
36.8
22
30
51.0
52
60
36.1
23
30
50.0
53
60
35.3
24
30
48.9
54
60
34.6
25
30
47.8
55
60
33.8
26
Outreach
Outreach
56
Outreach
Outreach
27
Outreach
Outreach
57
Outreach
Outreach
28
Outreach
Outreach
58
Outreach
Outreach
29
Outreach
Outreach
59
Outreach
Outreach
30
Outreach
Outreach
60
Outreach
Outreach
Expected
threshold
pressures in bold
It is more convenient to use ethanol in this experiment than water. However, it is not
essential. Water may be substituted if ethanol is a problem.
51/62
V.2 Appendix B
Institutional Letter of Endorsement
V.3 Appendix C
Statement of Supervising Faculty
V.4 Appendix D
Material Safety data sheets
V.5 Appendix E
Outreach consent and endorsement letters
62/62

Gravity Environments - Island Software Group

Transcription

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