2011 Bowman Scholars
Division of Engineering and Weapons
1/C Eric Arnold
- Major: Mechanical Engineering
- Title: Crack Growth and Propagation in 70xx Series Aluminum Alloys in Corrosive Environments
- Advisor: Assistant Professor Joel Schubbe - Mechanical Engineering Department
Crack Growth and Propagation in 70xx Series Aluminum Alloys in Corrosive Environments
Aerospace structural components are frequently constructed of aluminum plate products. These plate products do not exhibit uniform microstructures through the thickness of the plate, allowing for different orientations of the material to behave differently. This project will examine the susceptibility to stress corrosion cracking of Aluminum 7050 T-7451, an alloy which is becoming more common in the aerospace community, in the LS orientation relative to Aluminum 7085, an alloy with a historical corrosion problem. Compact tension test samples will be notched and pre-cracked in air before the crack is allowed to arrest and reach equilibrium. The samples will then be exposed to the corrosive environments of a sodium chloride solution simulating natural exposure in maritime environments, as well as a wash solution used for aircraft cleaning. Because naval aircraft are frequently exposed to each of these environments, this research will allow for relevant data collection and the determination of the existence of a cracking problem in Aluminum 7050.
1/C Matthew Carr
- Major: Mechanical Engineering
- Title: The Effects of Water Injection in a Variable Compression Otto Cycle Engine
- Advisors: Associate Professor Jim S. Cowart - Mechanical Engineering Department, Captain Leonard Hamilton, USN - Mechanical Engineering Department
The Effects of Water Injection in a Variable Compression Otto Cycle Engine
The purpose of this project was to explore the effect of water-fuel mixtures injected into a spark ignition engine on overall engine efficiency and performance. New direct fuel injection engine technology, allowing fuel and other liquid components (e.g. water) to be directly injected in the engine’s combustion chamber, provides a renewed interest in this century old technology. In the past water injection into the engine’s intake system has reduced the amount of air and fuel that could be delivered to the engine, and thus engine performance was reduced. With new direct injection technology, however, this limitation should be reduced significantly. This study will compare older water injection approaches directly to new ‘direct injection’ approaches in an effort to see if performance and engine efficiency can be improved as a result of increased octane resistance as well as volumetric efficiency gains. (This research project was undertaken during the spring 2011 semester).
1/C Adam Garfrerick
- Major: Electrical Engineering
- Title: The Design and Simulation of a Circuit Breaker for a Medium Voltage DC System
- Advisor: Associate Associate Professor John G. Ciezki - Electrical and Computer Engineering Department
The Design and Simulation of a Circuit Breaker for a Medium Voltage DC System
For my Bowman research project, I will simulate and build a low power prototype for a DC circuit breaker which could be used in a Medium Voltage (1-10 kV) Direct Current (MVDC) distribution system. This circuit will consist of three switches and an LC oscillator which will cause opposing current to flow into the system when a ground fault occurs, creating current zeros in the DC system. Much like an AC circuit breaker, the low power prototype of the MVDC circuit breaker will use the current zero to break the circuit. To effectively break a circuit the MVDC prototype breaker will use timing circuitry to break the circuit when a current zero occurs. When the oscillator and timing circuitry work properly together, the MVDC prototype will function like a normal AC circuit breaker, creating a simple solution to what has become a problem for the Navy’s advancement into MVDC ship power systems.
1/C Leslie Landry
- Major: Systems Engineering (Honors)
- Title: Next Generation Integrated Power System Stability Analysis
- Advisor: Associate Professor Edwin Zivi - Weapons and Systems Engineering Department
Next Generation Integrated Power System Stability Analysis
In response to rapid improvements in power electronics, the U. S. Navy is developing a family of Next Generation Integrated Power Systems. These systems are needed to enable future ships to use high power sensors and weapons to maintain tactical superiority. The objective of this research is to model, design, implement and demonstrate a controller for a representative low power low voltage power conversion module. Since these systems are vulnerable to instability, the controller must ensure system stability. A prototype will be ready for demonstration of the controller by the end of the Spring Semester. Specific steps that outline this project include: selecting an appropriate power conversion module, obtaining mathematical and Simulink models, establishing control performance objectives, developing a plan or approach for control, designing controller, simulating controller and tuning as required while obtaining and having working knowledge of a low power, low voltage power converter.
1/C Alexander Laun
- Major: Naval Architecture
- Title: Development and Design of a Six-axis, Single Strut Dynamometer for Hydromechanic Experimentation
- Advisor: Professor Gregory White - Naval Architecture and Ocean Engineering Department
Development and Design of a Six-axis, Single Strut Dynamometer for Hydromechanic Experimentation
The purpose of intended study is to research, design, and analyze an effective six-axis, single-strut towing dynamometer for use in the 120-foot towing-tank at the Naval Academy Hydromechanics Laboratory (NAHL). A towing dynamometer serves to resolve the basic forces and moments of ship motion, including surge, sway, heave, roll, pitch, and yaw. Currently, analysis of submerged hull-forms is greatly hindered by existing experimental testing devices: the common double-strut method is excruciatingly complex and any aft-mounted devices (“stings”) significantly alter the flow around the given body. Ultimately, a well-designed (calibrated), single-strut towing dynamometer would quickly provide information about the desired experimental parameters (six degrees-of-freedom) of ship motion, while simultaneously allowing for effective testing of submerged bodies, high-performance hull-forms, and a multitude of other entities.
1/C Jesse Marder
- Major: Aerospace Engineering
- Title: Hybrid Rocket Motors
- Advisor: Commander David Myre, USN - Aerospace Engineering Department
Hybrid Rocket Motors
Conventional hybrid rocket motors work by injecting a liquid or gaseous oxidizer down the length of a solid fuel grain where the two meet and combust in the presence of an igniter. An alternative, less researched, method for running a hybrid motor is to inject the oxidizer in a vortex, so that a greater proportion of the solid grain comes into contact with the oxidizer. This results in higher combustion efficiencies and greater motor performance. This method of inducing a vortex must be further investigated and studied to determine the best way of implementing it. I hope to redesign the present system so that it can better demonstrate the vortex method and can sustain longer tests. I will redesign the nozzle so that it can undergo longer and more frequent testing and will look into replacing the sensors that measure the combustion products. (This research project was performed in the Spring 2011 semester).
1/C Michael Martin
- Major: Systems Engineering
- Title: Enhancing Human / Robot Interaction Through a Virtual Reality System
- Advisor: Assistant Professor Sarangi Parikh - Weapons and Systems Engineering Department
Enhancing Human / Robot Interaction Through a Virtual Reality System
One of the current difficulties in using most touch-screen devices involves the lack of feedback the device provides when the user inputs incorrect information. The goal of this project is to design a system that provides haptic feedback to the user of a touch-screen device. This objective will be accomplished by designing a Matlab GUI that will notify the touch-screen user of an incorrect input via vibration motors and/or tri-color LEDs.
1/C Christopher Medford
- Major: Aerospace Engineering
- Title: High Energy Laser Damage Mechanisms for UAV Composites
- Advisors: Commander Joseph Watkins, USN - Mechanical Engineering Department, Associate Professor Peter Joyce - Mechanical Engineering Department
High Energy Laser Damage Mechanisms for UAV Composites
As directed energy weapons improve and evolve, the current material data and investigative techniques must change as well. It is important to understand the interaction that a directed energy weapon has with different materials. The purpose of this investigation is to study the effect that an incident laser beam of a given irradiance has on the strength of a standard 6-ply glass/polyester composite. The test will determine the trend of strength-loss as exposure time with the laser increases from initial contact to complete burn-through. Once the damage has been characterized, the test piece will be thoroughly investigated before it is subjected to a strength test in accordance with industry standards. Finally, in order to develop a theoretical approach for future studies, the different damage levels will be compared to holes created by a drill press. This process will be the beginning of a catalogue of material properties that have yet to be determined at a given wavelength of laser.
1/C Michael Moberg
- Major: Mechanical Engineering
- Title: Development of a Laser Detection System Within a Composite
- Advisor: Associate Professor Peter Joyce - Mechanical Engineering Department
Development of a Laser Detection System Within a Composite
Directed Energy Weapons are currently being developed in an effort to increase the United States’ ability to conduct wars in the future. Among the technologies being developed are lasers. An area of particular concern is the effects of high energy lasers on aerospace composite materials. The goal of the project is to develop a laser detection system that can be implemented into composites materials. This will require a system that is relatively small and lightweight as well as dispersed, in order to cover the entire surface in question. Another key consideration will be the ability to embed the system into a composite without incurring either undue complications to the manufacturing process or detrimental impacts to the material properties of the composite in question. Ideally, the system should be able to accurately identify a laser strike and be able to relay the detection signal with enough speed to allow for processing before the sample has been destroyed by the laser. Potential methods for detection include disruption of electrical signals, thermal changes, and optically detecting the beam. Breaks in electrical continuity will be tested using thin wires as well as various forms of carbon fiber. Thermal changes will be tested using thermocouples as well as carbon fiber or Bragg Diffraction gratings. Optical detection will explore the implementation of fiber optic cables and optical sensors.
1/C Daniel Schiavo
- Major: Electrical Engineering
- Title: Designing, Building and Testing of a Bi-directional Isolated DC-DC Converter
- Advisor: Associate Professor John G. Ciezki - Electrical and Computer Engineering Department
Designing, Building and Testing of a Bi-directional Isolated DC-DC Converter
Power is generated on current Navy ships by either steam turbines or gas/diesel engines. Separate generators convert mechanical energy into electrical power for the electrical loads and the combat systems on the ships. The Integrated Power System (IPS) proposes a way to make this process more spatially and cost efficient. In the IPS, both the propulsion system and the ship’s prime movers are integrated. The prime mover generators then convert all of the power produced into electrical power. That power is then connected to a common electrical bus, which can be used for both propulsion and auxiliary loads.
The project’s main goal will be to safely and effectively build a dc-dc converter that will be controllable in direction and will operate at voltages higher than experienced in classroom laboratory exercises (~200-300V). The main points of interest will be cost, size, implementation, and the resulting effects on performance such as efficiency. This will be accomplished by: creating a basic circuit model using simulation software, developing a control algorithm (which will allow control of the directionality of the circuit), prototyping at low power, designing a printed circuit board, and assembling and testing the final circuit.
The Integrated Power System will allow for greater efficiency, stealth, and combat capability for the Navy in the future. The key, however, is finding a suitable means for power conversion from the generator to propulsion and other electrical loads. Onboard ships, the bi-directional isolated dc-dc converter will be able to step down high dc voltages to low dc voltages, enabling it to power combat systems, life systems, and other auxiliary loads, as well as, charge a storage bank that could be used to send power to those same systems or back through the converter.
1/C Michael Shea
- Major: Mechanical Engineering
- Title: Computational Fluid Dynamics in Support of the ONR Ship Air Wake Project
- Advisor: Captain Murray Snyder, USN - Mechanical Engineering Department
Computational Fluid Dynamics in Support of the ONR Ship Air Wake Project
My research will consist of modeling the air flow around an F-18C operating at speeds from Mach 0.8 to supersonic while configured with the ATFLIR and Litening external targeting pods. Using state-of-the-art computational fluid dynamics (CFD) methods, I will be able to determine yaw and pitch moments on released external stores due to various phenomena such as interaction with shock waves generated by the ATFLIR or Litening Pod. The yaw and pitch moments will be used to determine the "miss distance" for a released store. In general, miss distances of stores to aircraft of less than 6 inches after initial release are deemed unsafe for fleet use. This miss distance will be calculated using numerical simulations of the complex flow generated by the aircraft and installed external targeting pods. These simulations are very demanding and typically require 15-20 million tetrahedrons (volumes where the flow is individually calculated).
1/C Kenan Wang
- Major: Electrical Engineering
- Title: Neural Network Applications in Iris Recognition
- Advisor: Associate Professor Robert Ives - Electrical and Computer Engineering Department
Neural Network Applications in Iris Recognition
Today, the iris recognition process uses the Hamming distance to compare two iris images and determine whether the two are match. A Hamming distance is a number of bit positions at which the corresponding iris templates are different. A small Hamming distance between two iris images means that one iris image is very similar to the other. Depending on the situation, the threshold of maximum Hamming distance for judging two iris images that are matched can be adjusted.
The project will develop code to create, test, and select possible useful features from known matched-eye templates to train a neural net to identify iris images. An important part of the project involves computing statistical parameters for each template, also as known as “features,” that could be used to distinguish one iris from another. These features are then evaluated for their usefulness in identification.
The training process in a neural network involves taking a set of iris image templates that are known to be from identical eyes or from different eyes, along with the statistical parameters (features) of the template. This information is passed into the neural net. Based on the ground truth, the neural net will determine which features are most important, and how each should be weighted to determine if an iris image is the same as another. Then, with the features optimally weighted, the system locks the already weighted and prioritized processing network. New iris images are processed and each template pair is input to the neural network, which outputs a verdict (same eye or different eyes). Performance can be determined if the ground truth of the new templates is known.
Division of Humanities and Social Sciences
1/C Kathryn Yanez
- Major: English
- Title: Passive Detection of Weapons of Mass Destruction
- Advisors: Professor Mark Harper - Mechanical Engineering Department, Professor Martin Nelson - Mechanical Engineering Department
Passive Detection of Weapons of Mass Destruction
The objective of this study is to determine the ability of ARDIMS to detect the presence of radioactive neutron emitting sources. The project will analyze neutron emissions from self-fissioning isotopes as a function of range, and the ARDIMS’ ability to distinguish a valid detection in a maritime environment taking into account background environmental interference, and the “ship effect”. The ship effect is the neutron signature developed from the cosmic ray induced neutrons interacting with the iron and other metals of which the vessel is constructed. This research will build upon the previous USNA studies of the neutron detection system within ARDIMS and the Spartan USV. The desired end result is to maximize the neutron detection success in a maritime environment in order to increase security at sea and effectively prevent weapons from illegally entering into U.S. territory. Maximum detection success will occur when the probability of false positives and negatives in minimized.
Division of Math and Science
1/C Joseph Beach
- Major: Physics
- Title: Integration of a High Frame Rate Camera into the Adaptive Optics System at the U. S. Naval Observatory
- Advisor: Assistant Professor Christopher Morgan - Physics Department
Integration of a High Frame Rate Camera into the Adaptive Optics System at the U. S. Naval Observatory
The main goal of this project was to improve the accuracy of flux measurements in the USNA/USNO Lensed Quasar Monitoring Program. My research involved integrating a tip-tilt tertiary mirror into the adaptive optics system of the Kaj Strand telescope at the United States Naval Observatory (USNO) in Flagstaff, Arizona. A tip-tilt system helps correct the effect of atmospheric conditions to first order. It simply adjusts an incoming image such that it remains properly centered and reduces twinkling or jitter. With this addition, we expect to improve the angular resolution of the telescope by approximately 40%, and thus reduce the limits of atmospheric seeing on observations. My advisor and I purchased, assembled, and lab tested the parts for this tip-tilt system during the spring semester of academic year 2009-2010. During my summer internship, we deployed the system to the 40 inch telescope for testing. For my SP495 course in the fall semester of 2010- 2011, we finalized the control software and return to USNA Flagstaff for a full system test.
1/C Zacgary Bunting
- Major: Mathematics
- Title: Direct and Inverse Problem in Laser Propagation
- Advisor: Assistant Professor Aurelia Minut - Mathematics Department
Direct and Inverse Problem in Laser Propagation
My problem arises from the fact that laser propagation varies through a non-homogeneous medium, such as the atmosphere. A direct propagation problem would be to determine the output given initial laser and atmospheric conditions. However, inverse problems deal with finding unknown properties of the atmosphere or any medium based on observations of how a system affects the input. Difficulty arises even in the one-dimensional problem when layering two media together. To make a well-posed problem, six conditions are needed. Once we determine the necessary measurements to make this a partial differential equation with a solution, we will work on patching together greater numbers of materials. This will give us greater information about laser propagation through atmosphere.
1/C Sidney Cheek
- Major: Quantitative Economics
- Title: Optimal Geographic Redistricting for Liver Transplant Allocation
- Advisor: Assistant Professor Sommer Gentry - Mathematics Department
Optimal Geographic Redistricting for Liver Transplant Allocation
The current regional system for allocating donated livers to eligible recipients is unjust and does not comply entirely with the Department of Health and Human Services “Final Rule,” which states that organs must be fairly distributed regardless of geography. The Model End Stage Liver Disease Score (MELD) assigns patients a score (from 0 to 40) based on the severity of their chronic liver disease. Livers should be allocated to those who have the highest MELD score which indicates those candidates who are the sickest. My research project will develop a model to ensure that livers are going to the sickest people in order to save lives, rather than to the people who benefit geographically but are not as critically ill. Distance is a factor. Studies have shown that livers should not be out of the body for more than ten to twelve hours. Also, survival rate for a transplant liver decreases as the time the liver remains out of the body increases. This project will maximize fairness across various regions and use distance as a constraint. Fairness will be quantified using MELD scores for severity and distance/time factor according to the Cold Ischemia Time. My main objective will be to find a model in which the geographic region plays a smaller role and the focus is placed on ensuring that the candidates who are sickest are receiving the livers available for allocation.
1/C Rebecca King
- Major: Physics
- Title: Acoustic Scattering and Imaging
- Advisor: Associate Professor Kevin McIlhany - Physics Department
Acoustic Scattering and Imaging
My project is an ongoing acoustics scattering and imaging project that has a physical apparatus under construction. The overall goal is to construct an apparatus which creates plane-wave sound pulses and records the time and position data of the wave after it has been scattered by a composite structure of spheres and ellipsoids, in order to accurately reconstruct an image of the object. The apparatus consists of a square grid of speakers on one plate, and a grid of receivers on a second plate, which will image an object between the two plates. I will continue writing a program with neural networks in Matlab, and with Comsol, which models the apparatus and simulates the acoustic scattering. The program will then use acquired data from simulations to interpolate the location, orientation and dimensions of the object. Throughout the project, I will alter various parameters to study which model gives the most accuracy.
1/C Grant Morgan
- Major: Physics
- Title: Strange Quark Production in Cu-Cu 22.6 GeV Collisions at RHIC
- Advisor: Assistant Professor Richard Witt - Physics Department
Strange Quark Production in Cu-Cu 22.6 GeV Collisions at RHIC
By analyzing data from 22GeV Cu+Cu collisions from the Relativistic Heavy Ion Collider (RHIC), this project will investigate the properties of nuclear matter, specifically analyzing the formation and process of quark-gluon plasma, QGP. This will be completed by analyzing the production of strange quarks in the following baryons: KS0’s, Λ’s, and anti-Λ’s. Strange quark production is associated with the formation of QGP. By conducting data cuts and analysis, this project will discover strangeness production’s dependence on the system size of the ions and the energy in the collision.
1/C Eowyn Pedicini
- Major: Chemistry
- Title: Level Scheme Construction of 169-Rhenium and Search for Wobbling
- Advisor: Prof. Daryl Hartley - Physics Department
Level Scheme Construction of 169-Rhenium and Search for Wobbling
The nuclear structure of 171Re will be investigated through a heavy ion fusion reaction. Using the Gammasphere spectrometer at Argonne National Lab, a high-energy beam of 55Mn will be used to strike a target of 120Sn in order to form 175Re. In order to dissipate energy, the nucleus will first undergo particle emission, in which four neutrons will be emitted, leaving 171Re. The off-center collisions between the beam and target nuclei will result in large amounts of angular momentum (spinning) in the new compound nucleus. To dispel this angular momentum, gamma rays will be emitted by the nucleus; these gamma rays will be detected using germanium detectors in Gammasphere. This gamma-ray data will be analyzed at the Naval Academy. Any gamma rays that are emitted in coincidence, or nearly simultaneously, come from one unpaired nucleon in its decay to the ground state. It is these decay sequences in 171Re that will be studied in this project to determine if the shape of this nucleus is asymmetric. Such a shape is extremely rare and if it exists, an exotic "wobbling" decay sequence will be observed.
It is often assumed that the nucleus of an atom is spherical; however, this is not always the case. At excited or high-spin states, where the nucleus is rotating very rapidly, it can either stretch or compress along a body-fixed, principal axis, giving it the shape of an American football or a doorknob. Very rarely, however, the nucleus can assume an asymmetric shape where it does not rotate around a principal axis. This wobbling motion is analogous to the spinning motion of an asymmetric top. The wobbling mode was first found in 163Lu and it was later found in 161, 165, 167Lu, leading to the theory that the wobbling mode was characteristic of the Z (proton number) ~72, N (neutron number) ~94 region. However, this mode was not observed in several neighboring Ta, Hf, and Tm isotopes, leading to the theory that the wobbling mode was specific to Lu. However, in 2009, the wobbling mode was found in 167Ta (N=94), reopening the question of how prevalent this phenomenon is. To answer this question, the level scheme of 171Re (N=96) will be constructed to see if it too exhibits the wobbling mode. Regardless of if the wobbling sequence is found or not, a better understanding of the phenomenon will be obtained.