Virginia Space Grant Consortium
Student Research Conference - April 18, 2011
Omni Hotel, Newport News, Virginia
Undergraduate Research Scholars
Poster Presentations – Ballroom C
REMOTE SENSING WITH LIDAR
Lindsey Andrews, Old Dominion University
Light Detection and Ranging (LIDAR) is a type of remote sensing that emits and collects pulses
of light for applications such as mapping or tracking. LIDAR can be applied in oceanographic
studies to examine the amount of scattering particles, such as phytoplankton biomass, in a water
column to generate primary production models. Using an “in-situ” LIDAR system, the research
project initiated at Old Dominion University (ODU) will investigate the vertical structure of the
ocean. The system will use a pulsed Nd:YAG laser, photomultiplier tubes for detection of the
return signal, and high-speed analog to digital conversion to record the data. The collected data
will then be applied to test existing models of biological productivity. In addition, the data will
complement archived records from NASA satellites (CALIOP and MODIS), obtained with
passive ocean color sensing. Compiling satellite data with LIDAR in situ data, integrated
primary production models can be constructed. We report progress on the design and
construction of the ODU LIDAR system.
MEASURING SENSITIZATION OF AA 5083 USING RESISTIVITY, NONLINEAR
ACOUSTICS, AND ATTENUATION
Aaron Bailey, University of Virginia
Because of their high strength-to-weight ratio and resistance to corrosion, 5xxx aluminum alloys
are in demand for many marine applications. However, catastrophic failure can occur in 5xxx
due to sensitization. This research focuses on evaluating potential nondestructive methods to
monitor sensitization in a 5083 aluminum alloy, including resistivity, nonlinearity, and
attenuation. The resistivity decreased during the sensitization treatments, and it showed the most
reliable trends in monitoring the degree of sensitization. Although the nonlinearity and
attenuation measurements show trends with sensitization heat treatment, more work is need to
reduce the variability in the measurements in order to better relate their behavior to sensitization.
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DEVELOPMENT OF A DIRECT SKIN FRICTION MEASUREMENT SYSTEM FOR
FLUID FLOWS VIA RETRACTABLE STRAIN GAGES
Gordon Civalier, Virginia Tech
A new floating element direct skin friction measurement balance has been developed by the
author and past undergraduate and graduate students at Virginia Tech employing three aligned
cantilever force sensors contacting a circular floating head. The existing design has been
compared to other direct methods under investigation by other researchers, and improved to
allow a vertical wall mounting based on the addition of a hot glue adhesive applied and removed
using a hot plate. A user friendly LabView GUI has also been developed to allow intuitive
operation. The system has been demonstrated to within 10% agreement with boundary layer
theory in the low speed subsonic Cascade Tunnel at Virginia Tech, and methods have been
developed to test the instrument in the Stability Wind Tunnel, with these tests occurring under
the hand of a new graduate researcher. It is hoped that the advances made by the author of this
report and his colleagues will allow the project to be completed after forthcoming Stability
Tunnel tests are undertaken.
VECTOR MAGNETOMETER USING RB VAPOR
Kevin Cox, College of William and Mary
This project demonstrates an optical method for measuring the strength and direction of
magnetic fields using Electromagnetically Induced Transparency in rubidium vapor. Inside
rubidium, the Zeeman effect causes atomic states to shift when an external magnetic field is
applied. The magnitude of these shifts, and consequently the strength of the magnetic field, can
be measured by recording electromagnetically induced transparency (EIT) resonances with tuned
laser fields. Furthermore, since the atom’s interactions with the laser field are dependent on the
direction of the magnetic field and the laser polarization, we are able to discover the direction as
well as the strength of the magnetic field. With a feasible precision down to 10fT and the
possibility of complete field mapping, this magnetometer can be useful for medical, materials
testing, geo-sensing, and navigation applications.
TIME DEPENDENCE OF POLAR MESOSPHERIC CLOUD BRIGHTNESS
John Jones, Hampton University
Northern Hemisphere 2007 Polar Mesospheric Cloud (PMC) season data from the Cloud
Imaging and Particle Size Experiment (CIPS)instrument on the Aeronomy of Ice in the
Mesosphere (AIM) satellite was analyzed to study the time dependence of overlapping regions of
consecutive orbits. A correction for local time was developed as a function of latitude and
applied to the raw data. This raw and corrected data was then analyzed using a Spearman rank
correlation for the months of June, July, and August. The average correlation per month shows a
small yet significant value for the first consecutive orbit, whereas the average correlation with
later orbits appears to be approaching a nonzero asymptotic value. The effects of the local time
correction on the correlation are shown to be negligible.
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THE DEVELOPMENT OF A LARGE SCALE DIAGNOSTIC TDLAT SYSTEM FOR
DETERMINATION OF SPECIES CONCENTRATION AND TEMPERATURE IN
SCRAMJET EXHAUST
Stuart Keech, University of Virginia
A Tunable Diode Laser Absorption Tomography (TDLAT) system is being developed for the
NASA Langley Direct-Connect hypersonic combustion wind tunnel. This diagnostic method is a
non-intrusive technique for measuring two-dimensional spatially resolved distributions of
species concentration and temperature. While a similar system has been demonstrated at the
University of Virginia hypersonic combustion wind tunnel, the size and installation difficulties
of the NASA wind tunnel present many design challenges. This paper addresses these design
challenges, presents solutions, and maps out the progress to-date, and future goals of the project.
Specifically, the software controls have been optimized in order to speed up the entire system.
Coupled with hardware changes, these improvements will account for a 94 percent decrease in
the run time required to obtain a complete data set.
MULTISCALE MODELING OF DAMAGE EVOLUTION DUE TO MONOTONIC AND
CYCLIC LOADING OF ENERGETIC MATERIALS
John Kiefer, Virginia Tech
A two dimensional finite element analysis was performed on a uniaxial bar problem simulating
both monotonic and cyclic loads imposed on a particle reinforced composite model. The model
of the composite consisted of a system of elastic grains adhered together by a variety cohesive
zones. Several finite element analyses were performed and general qualitative trends were
observed. These trends describe how the stress strain response of the composite depends on the
grain system and finite element mesh structure used to model the composite.
GIS STUDY TO CHARACTERIZE POTENTIAL INTERACTION BETWEEN
VIRGINIA’S COASTAL AEROSPACE ACTIVITIES AND OFFSHORE ENERGY
DEVELOPMENT ON VIRGINIA’S OUTER CONTINENTAL SHELF
Bryan Murray, Virginia Tech
The ocean off the coast of Virginia is a valuable economic resource, supporting numerous public
and private activities. Private parties have made moves toward investing in Offshore Wind
Energy in Virginia’s Outer Continental Shelf, but these initiatives have been met with both
encouragement and apprehension from public institutions in the area. NASA’s Wallops Flight
Facility is the origination point for various aerospace missions that would operate in the vicinity
of planned wind energy investments. NASA officials and wind farm developers have a mutual
interest in determining precisely how aerospace activities could threaten energy investments.
NASA’s activities in the area, especially sub-orbital sounding rocket launches, have well
established operating patterns; the area currently being considered for wind energy develop is
well defined by the U.S. Department of the Interior. These two known parameters facilitate a
quantitative analysis of possible interactions between NASA activities and wind energy
infrastructure off Virginia’s coast.
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DEVELOPMENT OF AN ELECTROACTIVE POLYMER SENSOR FOR USE IN A
NOVEL ARTIFICIAL CELL
Lynna Nguyen, University of Virginia
The ultimate goal of this project is to connect many artificial excitable cells together to produce a
medium exhibiting contraction similar to the heart. A proposed polymer-based excitable cell
design under development at UVA mimics the excitability and refractoriness of biological
cardiac myocytes. This contracting medium will be used to develop a tube pump capable of
propelling fluids along its length. Re-evaluating current pumping systems has the potential to
free up precious space, energy, and weight aboard spacecraft.
As a part of these artificial cells, an ion-sensitive probe is needed to detect the presence, location,
and concentration of potassium ions within the cell. It is a crucial element needed to incorporate
excitability within the artificial cell. For this research project, a potassium-selective ion sensor
was reproduced following research by Pandey, Singh, and Shrivastava (2002) and tested for
functionality within hydrogels based on research by Barthus, Lira, and Cόrdoba de Toressi
(2008). A linear relationship between ion concentration and voltage drop of the sensor within
the hydrogel was observed, and therefore it is predicted that the sensor will function properly and
be easily incorporated into an artificial excitable cell with a hydrogel foundation.
COMPUTER SIMULATIONS OF CARBON NANOTUBES AND NANOCOMPOSITE
MATERIALS FOR THERMAL PROTECTION SYSTEMS
David Nicholson, University of Virginia
Carbon nanotube (CNT) reinforced nanocomposite materials show promise for use in thermal
protection systems on spacecraft. Computational modeling has shown to be an effective
technique for understanding the mechanical and thermal properties of these materials. A coarsegrained model is being developed in order to perform efficient, dynamic calculations for pure
CNT and CNT reinforced nanocomposite materials. One of the shortcomings with the current
coarse-grained model is that it fails to reproduce the dissipation of mechanical vibrations, such as
bending and stretching, into thermal motion which would is observed in real CNTs. In order to
overcome this problem, a heat bath approach is described in which an artificial temperature is
assigned to each individual CNT to account for atomic-scale vibrations not present in the coarsegrained model. Through damping forces, energy is transferred from the mechanical vibrations
into the artificial heat bath. The rate at which the energy is transferred will reflect the rates of
energy transfer observed in atomistic simulations. As a proof of concept, arbitrary decay rates are
chosen and the performance of the heat bath model is evaluated.
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QUALITATIVE STUDY OF PARTICLE IMPACT PATTERNS WITHIN TURBINE
BLADE COOLING PASSAGES
Adam Shoemaker, Virginia Tech
Gas turbine engines feature a large combination of precisely machined interacting components.
Likewise, the stability and efficiency of gas turbines is directly dependent on the condition of
these components within the engine. As particles such as dust, sand, ash, etc. enter into the
engine, a series of erosive and depositional processes occur. Often unavoidable, these
occurrences directly influence many of the engine’s components, causing mechanical
breakdown. In the event of breakdown, the ability of the engine to operate can be drastically
influenced. In mild cases, the efficiency will be lowered causing excessive fuel usage, whereas in
the most extreme cases total engine failure may result in a compromise to safety. Previous work
at Virginia Tech has yielded Computational Fluid Dynamic (CFD) models predicting the
behavior of particles flowing within a two pass blade cooling channel. This paper presents work
done in qualitative experiments aimed at reproducing the results of the CFD models. It will start
with a background that details relative events as well as particular research in this area. From this
background, the team developed an appropriate experiment to validate the CFD models which
will be used for comparison at a later date.
EQUILIBRIUM SURFACES OF TENSEGRITY STRUCTURES
Zachary Sternberger, Virginia Tech
Tensegrity structures rely on the interaction between tension and compression elements to
maintain equilibrium. A specific form of symmetric tensegrity structure is defined and
generalized. Two methods are presented to determine the conditions under which the structure is
in equilibrium. One method is based on nodal equilibrium and the second on the minimization
of strain energy. The tensegrity structure will also possess an infinitesimal mechanism allowing
for efficient deflection along a path specific to each equilibrium condition. The calculation of
the direction of the infinitesimal mechanism is generalized. These methods are applied to two
specific tensegrity structures. The resulting equilibrium path and infinitesimal mechanism
functions describe the range of motion possessed by the structure.
RUNWAY CONFIGURATION MANAGAGEMENT
Jennifer Thorne, College of William and Mary
Runway Configuration Management assigns combinations of runways to be used at an airport or
a collection of airports (a metroplex). Configurations of runways are changed as a result of
weather patterns and alterations in arrival and departure demand. Each configuration has a
Runway Configuration Capacity Envelope, which dictates the number of arrivals and departures
that can be accommodated based on the runways in use. We developed a condition-based
heuristic to select the appropriate runway configuration based on a ranking scheme and the
current airport conditions. Data from John F. Kennedy International Airport was used to develop
test cases.
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