Summer 2007 Poster Session Abstracts
First, Second, and Third Place Winners

Presentation of Awards
From left: Dr. Michael Pestorius, ARL:UT Independent Research & Development Coordinator; Christy Habecker, ARL:UT Educational Programs Coordinator; Vian Nguyen, second place winner; Jack Wimberley, first place winner; Ashley Bowie, third place winner; & Dr. Clark Penrod, ARL:UT Executive Director

1st Place, Poster Presentation
Modeling and Study of Electromagnetic Plate Launchers for Use as Armor
By Jack Wimberley
Anderson High School
Supervisors: Dr. Harry Fair & Dr. John Mallick; Institute for Advanced Techonology

Abstract
Explosive-reactive armor (ERA) is effective against anti-tank munitions, but cumbersome and heavy for lighter vehicles such as personnel carriers. A possible replacement for ERA with less bulk and nearly equal defensive capabilities is electromagnetic armor (EMA). Such electromagnetic armor could come in numerous configurations. In this paper, the feasibility of a coil-plate transformer for use as EMA is studied through analytical and numerical modeling and finite element simulation. A functional such transformer is built and tested to evaluate the various analyses.

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2nd Place, Poster Presentation
Modeling Acoustic Propagation of Noise fromSurface Ships in a Deep Ocean Environment
By Vian Nguyen
Westwood High School
Supervisors: Jack Shooter and Dr. David Knobles, Environmental Sciences Laboratory, ARL:UT

Abstract
In 1988 an experiment code named NORPAC was conducted in the Philippine Sea. A vertical line array (VLA) of hydrophones was deployed to record in part ambient noise below the critical depth. The ambient noise included the received acoustic spectra of ships that passed near the VLA. There are several unknown properties about the experiment including the location of the VLA, the sound speed profile (SSP), the properties of the sea bed, and the tracks of the passing ships. With estimates of the ship’s distance from the VLA, ship speed, intrinsic geometry of the hydrophones on the VLA, and the geoacoustic properties of the seabed; simulated low frequency and ranging (LOFAR) grams of the noise are generated and compared with those derived from the measured acoustic data. Adjustments are made to the relative positions of the ships to the VLA, the sound speed profile, and the geoacoustic profile until the data and model comparison is optimized. This analysis approach is a basic example of an inversion methodology that can potentially be used to localize ships employing their acoustic emissions.

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3rd Place, Poster Presentation
The Effects of Varying Edge Information on Object Recognition
By Ashley Bowie
Crockett High School
Supervisor: David Wick, Signal & Information Systems Laboratory, ARL:UT

Abstract
Edge detection and object recognition are imperative to many different technologies, and the biological basis of these processes is integral to advancement of the field itself. In this study an evaluation was made of human capacity to recognize an object under altered conditions and after computer processing. In a two part design, participants were first asked to identify the outlines of common objects in various states of completeness. It was then asked that participants identify similar objects (in varying states of completeness) after being filtered though a common edge detection program. Preliminary results indicate object recognition requires a surprisingly great majority of an object to be visible and that the presence of subtle visual clues (e.g. shading, texture, minor object details) increases the frequency of accurate identification even under partial visibility.

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Presentation of Awards
From left: Dr. Clark Penrod, ARL:UT Executive Director; Christi Habecker, ARL:UT Educational Programs Coordinator; Srikanth Kodali, third place winner; Nicole Varnado, second place winner; Carl Richardson, first place winner; and Dr. Michael Pestorius, ARL:UT Independent Research & Development Coordinator

1st Place, Poster Presentation
Display Gun Diagnostics
By Carl Richardson
Del Valle High School
Supervisors:  Dr. Mark Crawford, Dwayne Surls, and Alex Sitzman; Institute for Advanced Techonology

Abstract
The purpose of this project was to fabricate the necessary diagnostic equipment to collect data from the display rail launcher. Collected data included armature position inside the bore, breech, shunt and armature current, and the breech voltage. To measure current, Rogowski coils were utilized around the positive rail clamp and the muzzle shunt. Rogowski coils were ideal because they are easily fabricated, easy to calibrate, and produce a voltage directly proportional to the rate of change in the current flowing through the conductor. The Rogowski coils were calibrated by utilizing an additional current sensor with a known amps/volts ratio around the muzzle shunt. The gun was then fired without an armature at a low voltage. To detect armature position an array of B-dot probes was mounted under the bore of the gun. As the armature passed though the bore, the electromagnetic field around the armature would induce a voltage in the windings of the B-dot probes in relation to armature position and current flow.

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2nd place, poster presentation

A Visualization of Interfering Signals in LWDA Data
By Nicole Varnado
McNeil High School
Supervisor: Dr. Tom Gaussiran, Space & Geophysics Laboratory, ARL:UT

Abstract
Modern radio telescopes collect data in frequency ranges that are often contaminated by a multitude of interfering man-made signals.  The Long Wavelength Array (LWA) is a proposed radio telescope designed to operate in the relatively unexplored frequency range of 20 to 80 MHz.  The radio frequency interference (RFI) in this frequency band is generated by sources including television, FM radio stations, and High Frequency communications. Transmissions from such sources of RFI are expected to adversely affect LWA radio observations. 

The goal of this project was to create a visual depiction of RFI signals from sample measurements mirroring LWA data.  Using the programming language Python, I created animations that included spectrograms, power spectrum, and power time graphs that eased identification of man-made signals. The spectrogram animation showed the intensity of collected frequencies over time, and the spectrum and power time plots conveyed power of the signals in the frequency and time domains, respectively.  In this project, I will create more focused, detailed animations of multiple data samples.  From this, I will be able to identify both impulsive and continuous RFI signatures within samples. 

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3rd place, poster presentation

Testing for Reliability of Components Used in the Joint Biological Point Detection System
By Srikanth Kodali
Connally High School
Supervisor: Jeffrey Michalski, Space & Geophysics Laboratory, ARL:UT

Abstract
Rigorous inspection and evaluation standards were evolved for the many components that comprise the Joint Biological Point Detection System.  These tests were applied to various units and assemblies over the course of approximately three months, allowing for segregation of improperly functioning components from the working components.  The use of these industrial techniques, in combination with a closely-regulated manufacturing system allowed for the successful fabrication and delivery of the JBPDS collector line replaceable units (LRUs).  The manufacturing process and the rules that govern it are as necessary as the initial research and development phase that was required to develop the JBPDS.  Quality testing of the parts revealed defective components and gave an understanding of the basic causes of failure, such as inherent or manufacturing flaws.  This gives an informed understanding of the probable yields and reliability of unit, and allows for maximum cost-effectiveness.  The different components that go into the JBPDS have been subject to electrical and other tests both under nominal and stress conditions.  A brief functional description of the various parts is provided along with stress conditions, test results and evaluation.

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Summer 2005 Poster Session Abstracts
First, Second, and Third Place Winners

First Place

The Effect of a Ground Reflector on Long Wavelength Development Array (LWDA) Antenna Performance

By Erika Hetherington
Westwood High School
Supervisor: Dr. David Munton, Space & Geophysics Laboratory, ARL:UT

Abstract
The Long Wavelength Development Array (LWDA) is a prototype for the planned Long Wavelength Array (LWA), a large radio astronomy telescope to be located throughout New Mexico. Researchers from ARL:UT have developed an antenna prototype to be used in the LWDA. The objective of this project is to investigate the impact of placing a metal ground reflector beneath the antenna. Several tests were conducted, including measurements of antenna gain with and without a ground reflector, over multiple angles of signal reception. Also measurements were taken of antenna impedance matching with and without a ground reflector. Finally, sky noise measurements were performed. Measured data was compiled and analyzed using computer scripts, and was then compared to results from computer simulations. From this analysis, conclusions are drawn as to the improvement in antenna performance due to installing a ground plane.

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Second Place

Light Bulbs as an Underwater Acoustic Source

By Shaun Sherman
Waller High School
Supervisor: Dr. David Knobles, Environmental Sciences Laboratory, ARL:UT

Abstract
Over the years, underwater sources have varied greatly in type, efficiency, and cost. Explosive TNT sources such as Sound Underwater Signaling (SUS) were popular for many years. However, recent environmental restrictions have put a halt to use of this type of underwater source. The intrinsic properties of a light bulb make it a useful source for generating underwater sound. When the bulb is placed below the surface of the water, the vacuum inside the bulb allows an implosion to occur when the glass shell is compromised. This forms a bubble, which oscillates at a diminishing level until all the ambient potential energy is transformed into mechanical energy, sound radiation, and heat. The purpose of this project is to accurately measure the characteristics of light bulb implosion source waveforms as a function of depth of implosion and evacuated volume of the light bulb.

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Third Place

Operational & Capability Enhancements for a
Railgun Bore Inspection Tool

Abstract
The purpose of our project has been to design and build a replacement for a bore inspection tool that was created last year. Our supervisors supplied us with some general guidelines of the capabilities and features that we should incorporate into our device, as well as various ways to improve previous features of the older device. The purpose of having such a tool is for assessing damage that occurs inside the bore of a rail gun after every launch, without having to disassemble the gun. Our tool is in the form of a small robotic vehicle, with a miniature camera mounted on the front, drive train and an encoder setup to transmit distance data back to the operator. The entire setup is wireless for ease of use, and required a good amount of custom fabrication, programming and electrical engineering knowledge and research to complete.

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First Place

Digital Analysis of Behind-Armor Debris (BAD) Witness Plates
By Tracy Hooten
Stony Point High School
Supervisor: Dr. Stephan Bless, IAT

The desire to create a foundation for the behind-armor debris (BAD) model stems from the lethality of behind-armor effects. While previous methods analyzed the witness packs manually, this procedure attempts to digitally capture and analyze BAD data. Each plate was digitally photographed, scanned through ImageJ (NIH software), and the results sorted and modified through Microsoft Excel and a C++ program. The results provided the polar and linear coordinates of the holes in respect to the impact center, displayed the angle of trajectory, sorted the holes into predefined rings, quarters and sub-quarters by number of particles and also total area, and determined which particles created multiple holes through the five witness plates. Further research is needed to analyze results from the debris hole matching program and the Excell area sorting, while also more witness packs need analyzed through this process to refine the data matching and sorting methods.

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Second Place

Analysis of Archival Data
By Ryan Renfrow
McNeil High School
Supervisor: Jack Shooter, ARL:UT, ESL

The purpose of this project was to analyze the acoustical data recovered from the 1975 Church Opal Exercise conducted in the northeastern Pacific Ocean. This multi-million dollar exercise was sponsored by the Long Range Acoustic Propagation Project (LRAPP) of the Naval Ocean Research and Development Activity. Our analysis was conducted through the use of Matlab and the MCS toolbox, the latter developed by ARL scientist Evan Westwood. Goals for the analysis of the data included a complete visual record of the ten day audio source using LOFAR Grams, a detailed analysis of key Lofar Grams of special interest, and ship range estimates using cross correlations (CGRAMS) of several hydrophone pairs. Overall, this summer extended our knowledge of the data to aide with several ongoing projects in long range acoustic propagation, while we also identified several new signals from whales and surveillance aircraft. These objectives proved to be a convincing method in obtaining a deeper understanding of underwater acoustics and its properties.

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Gunshot Location and Frequency Analysis using Acoustics
By James Milkey
Connally High School
Supervisor: Martin Barlett, ARL:UT, SISL

Recently methods have been researched to create a mobile device for calculating the location of origin of gunfire for military applications. Although accuracy of such methods increases with the number of microphones utilized, in theory such calculations should be possible with just two or three microphones mounted on a soldier’s helmet. In order to simulate microphones mounted on a helmet, two microphones were lined up approximately 10 inches apart from each other, and gunshots coming from different angles relative to the two-microphone system were recorded using five guns at Gary Wilson’s ranch. The data was then used to calculate the angles relative to the system at which the guns were fired, and to analyze the frequency spectrum of the acoustic characteristics of each of the five guns used.