abstracts undergraduate 2010-2011 draft

8/13/2019 Abstracts Undergraduate 2010-2011 DRAFT

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Virginia Space Grant Consortium

Student Research Conference - April 18, 2011

Omni Hotel, Newport News, Virginia

Undergraduate Research Scholars

Poster PresentationsBallroom C

REMOTE SENSING WITH LIDARLindsey 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 oceanographicstudies 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 thereturn 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 withpassive 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 alloysare 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 mostreliable 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 alignedcantilever force sensors contacting a circular floating head. The existing design has beencompared 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 intuitiveoperation. 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 thisreport 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 isapplied. 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 atoms 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 aswell 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 BRIGHTNESSJohn 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 theMesosphere (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 asmall 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 EXHAUSTStuart Keech, University of Virginia

A Tunable Diode Laser Absorption Tomography (TDLAT) system is being developed for theNASA Langley Direct-Connect hypersonic combustion wind tunnel. This diagnostic method is anon-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 difficultiesof 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 inthe 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 cohesivezones. 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

VIRGINIAS COASTAL AEROSPACE ACTIVITIES AND OFFSHORE ENERGY

DEVELOPMENT ON VIRGINIAS OUTER CONTINENTAL SHELFBryan 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 Virginias Outer Continental Shelf, but these initiatives have been met with both

encouragement and apprehension from public institutions in the area. NASAs Wallops FlightFacility 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.

NASAs activities in the area, especially sub-orbital sounding rocket launches, have wellestablished 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 energyinfrastructure off Virginias 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 celldesign under development at UVA mimics the excitability and refractoriness of biologicalcardiac 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 sensorwas reproduced following research by Pandey, Singh, and Shrivastava (2002) and tested for

functionality within hydrogels based on research by Barthus, Lira, and Crdoba de Toressi

(2008). A linear relationship between ion concentration and voltage drop of the sensor withinthe 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 coarse-grained 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 asbending 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 coarse-grained 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 PASSAGESAdam 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 ofthese components within the engine. As particles such as dust, sand, ash, etc. enter into theengine, a series of erosive and depositional processes occur. Often unavoidable, these

occurrences directly influence many of the engines components, causing mechanical

breakdown. In the event of breakdown, the ability of the engine to operate can be drasticallyinfluenced. 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 workdone 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 whichwill be used for comparison at a later date.

EQUILIBRIUM SURFACES OF TENSEGRITY STRUCTURESZachary Sternberger, Virginia Tech

Tensegrity structures rely on the interaction between tension and compression elements tomaintain 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 allowingfor 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 mechanismfunctions describe the range of motion possessed by the structure.

RUNWAY CONFIGURATION MANAGAGEMENTJennifer Thorne, College of William and Mary

Runway Configuration Management assigns combinations of runways to be used at an airport ora 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-basedheuristic 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.

abstracts undergraduate 2010-2011 draft

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