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Air Force Institute of Technology

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Decision Analysis Using Value-Focused Thinking For Infrastructure Prioritization, Mona A. Tenorio Mar 2005

Decision Analysis Using Value-Focused Thinking For Infrastructure Prioritization, Mona A. Tenorio

Theses and Dissertations

Infrastructure systems and facilities have deteriorated due to the impact of limited defense funding and competing priorities within the Air Force. The current method used for infrastructure prioritization is influenced by political sensitivity and uncertainty regarding the consequences of various funding decisions. Senior leaders need to better understand how their funding decisions will impact the overall condition and service life of the installation's infrastructure systems and facilities. The purpose of this research was to improve the method of prioritizing infrastructure projects through the use of a decision analysis methodology known as Value-Focused Thinking. The value model was created based on …

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Evaluation Of Fuel Oxygenate Degradation In The Vadose Zone, David A. Torres Mar 2005

Evaluation Of Fuel Oxygenate Degradation In The Vadose Zone, David A. Torres

Theses and Dissertations

Groundwater contamination by petroleum products poses a potential human health and safety risk. Methyl tert-butyl ether (MTBE) was a commonly used fuel oxygenate that was added to gasoline to meet environmental regulations. The widespread use of MTBE resulted in significant contamination of drinking water supplies across the United States. This research evaluated the degradation characteristics of potential alternative fuel oxygenates in the vadose zone. One fuel oxygenate being considered as an alternative to MTBE is diisopropyl ether (DIPE). Specifically, this thesis sought to answer three research questions: what is the potential for DIPE degradation in soil without prior microbial augmentation, …

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An Analysis Of Biometric Technology As An Enabler To Information Assurance, Darren A. Deschaine Mar 2005

An Analysis Of Biometric Technology As An Enabler To Information Assurance, Darren A. Deschaine

Theses and Dissertations

The use of and dependence on, Information technology (IT) has grown tremendously in the last two decades. Still, some believe the United States is only in the infancy of this growth. This explosive growth has opened the door to capabilities that were only dreamed of in the past. As easy as it is to see how advantageous this technology is, it also is clear that with its advantages come distinct responsibilities and new problems that must be addressed. For instance, the minute one begins using information processing systems, the world of information assurance (IA) becomes far more complex. As a …

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Web Usability Guidelines For Air Force Knowledge Now Web Site, Gary A. Felax Mar 2005

Web Usability Guidelines For Air Force Knowledge Now Web Site, Gary A. Felax

Theses and Dissertations

The Department of Defense Net-Centric Data Strategies number one key attribute is to ensure data is visible, available, and usable when and where needed to accelerate decision-making. The Internet provides opportunities for quick and efficient disseminating of information to the public, distributing information throughout the Air Force, and accessing information from a variety of sources. In 2002, the Air Force CIO designated the Air Force Knowledge Now (AFKN) as the center of excellence for Knowledge Management. The site is a one-stop resource, providing access to a great depth and breadth of information. This study seeks to determine how usable and …

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Assessing The Usefulness Of The Decision Framework For Identifying And Selecting Knowledge Management Projects, Kevin G. Budai Mar 2005

Assessing The Usefulness Of The Decision Framework For Identifying And Selecting Knowledge Management Projects, Kevin G. Budai

Theses and Dissertations

Knowledge management (KM) is becoming recognized as a valuable tool for the Department of Defense (DoD) in its effort to maintain a competitive, strategic advantage against its enemies in a new threat environment. Decision superiority is the ultimate end result and is only possible through the effective and efficient use of its chief key resource--knowledge. As the Air Force seeks to transform the way it does business the concept of knowledge management has made its way to the forefront of both the Air Force's Information Strategy and Information Resource Flight Plan. This research assesses the usefulness of a knowledge management …

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Key Issues In The Application Of Knowledge Management In Education, George A. Mendoza Mar 2005

Key Issues In The Application Of Knowledge Management In Education, George A. Mendoza

Theses and Dissertations

Today's world is a fast moving place in which decisions are made with an ever-increasing speed, and the success of an organization rests on its ability to correctly make these decisions. This shift in paradigms has made knowledge the key resource as organizations shift their focus from natural resources to intellectual assets, heralding the use of a concept called Knowledge Management (KM). Despite its acceptance and use in commercial organizations, KM is not being applied in the academic world. No KM models exist for educational use, and no other studies into this topic can be found. This research establishes a …

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Assessing The Usefulness Of Visualization Tools To Investigate Hidden Patterns With Insider Attack Cases, Amy M. Rammel Mar 2005

Assessing The Usefulness Of Visualization Tools To Investigate Hidden Patterns With Insider Attack Cases, Amy M. Rammel

Theses and Dissertations

The insider threat is a major concern for organizations. Open markets, technological advances, and the evolving definition of employee have exacerbated the insider threat. Insider threat research efforts are focusing on both prevention and detection techniques. However, recent security violation trends highlight the damage insider attacks cause organizations and illuminate why organizations and researchers must develop new approaches to this challenge. Although fruitful research is being conducted and new technologies are being applied to the insider threat problem, companies remain susceptible to the costly damage generated by insider threat actions. This research explored how visualization tools may be useful in …

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An Eleven Year Retrospective Of The Acquisition Review Journal, Mitchell J. Elder Mar 2005

An Eleven Year Retrospective Of The Acquisition Review Journal, Mitchell J. Elder

Theses and Dissertations

The purpose of this research was to examine the evolution of the Acquisition Review Journal (ARJ) through its first 11 years of publication. Researchers assessed the Defense Acquisition community through a review of ARJ articles. They considered what areas academics and practitioners have explored, and how they have explored them. This review documents such characteristics as areas of study, methods of study, and contributors. Trends are identified and conclusions are drawn as to the contribution of the ARJ to the Defense Acquisition community of practice.

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Weapon Release Scheduling From Multiple-Bay Aircraft Using Multi-Objective Evolutionary Algorithms, Francis R. Lyons Iv Mar 2005

Weapon Release Scheduling From Multiple-Bay Aircraft Using Multi-Objective Evolutionary Algorithms, Francis R. Lyons Iv

Theses and Dissertations

The United States Air Force has put an increased emphasis on the timely delivery of precision weapons. Part of this effort has been to us multiple bay aircraft such the B-1B Lancer and B-52 Stratofortress to provide Close Air Support and responsive strikes using 1760 weapons. In order to provide greater flexibility, the aircraft carry heterogeneous payloads which can require deconfliction in order to drop multiple different types of weapons. Current methods of deconfliction and weapon selection are highly crew dependent and work intensive. This research effort investigates the optimization of an algorithm for weapon release which allows the aircraft …

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Temperature Dependent Current-Voltage Measurements Of Neutron Irradiated Al0.27Ga0.73N/Gan Modulation Doped Field Effect Transistors, Troy A. Uhlman Mar 2005

Temperature Dependent Current-Voltage Measurements Of Neutron Irradiated Al0.27Ga0.73N/Gan Modulation Doped Field Effect Transistors, Troy A. Uhlman

Theses and Dissertations

In this research, the first ever neutron irradiation study of AlGaN/GaN MODFETs was conducted. Devices irradiated to a total 1 MeV Eq (Si) neutron fluence of 1.2x1016 n/cm2 demonstrated the temperature dependence of irradiation and annealing. Devices irradiated at 80 K exhibited significant persistent electrical degradation at only 5.4 rad (Si), whereas those irradiated at elevated temperatures exhibit transient increases in gate and drain current up to 400 krad (Si). I-V measurements indicate substantial radiation-induced increased gate and drain currents occur only at low-temperature irradiations. The introduction of a high-density of donor defects is hypothesized as the primary …

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An Approach For Optimizing The On-Orbit Servicing Architecture For The Space-Based Radar Constellation, Michael L. Mcconnell Mar 2005

An Approach For Optimizing The On-Orbit Servicing Architecture For The Space-Based Radar Constellation, Michael L. Mcconnell

Theses and Dissertations

Satellite systems, once operational, are essentially a consumable item with no capacity to maintain, repair, or upgrade them while on-orbit. In order to avoid having to replace costly space assets, the Defense Advanced Research Projects Agency (DARPA) and Air Force Space Command (AFSPC) are looking to developing programs to provide an on-orbit servicing capability for future satellite systems under development, such as the Space-Based Radar (SBR) system. DARPA and AFSPC are studying on-orbit servicing using the Orbital Express platform as part of an Analysis of Alternatives for the SBR program. Like their satellite clients, on-orbit servicing assets are expected to …

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Modeling Information Quality Expectation In Unmanned Aerial Vehicle Swarm Sensor Databases, Patrick D. Baldwin Mar 2005

Modeling Information Quality Expectation In Unmanned Aerial Vehicle Swarm Sensor Databases, Patrick D. Baldwin

Theses and Dissertations

Swarming Unmanned Aerial Vehicles (UAVs) are the future of Intelligence, Surveillance and Reconnaissance (ISR). Swarms of hundreds of these vehicles, each equipped with multiple sensors, will one day fill the skies over hostile areas. As the sensors collect hundreds of gigabytes of data, telemetry data links will be unable to transmit the complete data picture to the ground in real time. The collected data will be stored on board the UAVs and selectively downloaded through queries issued from analysts on the ground. Analysts expect to find relevant sensor data within the collection of acquired sensor data. This expectation is not …

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Optimization Model For Base-Level Delivery Routes And Crew Scheduling, Young-Ho Cha Mar 2005

Optimization Model For Base-Level Delivery Routes And Crew Scheduling, Young-Ho Cha

Theses and Dissertations

In the U.S. Air Force, a Logistic Readiness Squadron (LRS) provides material management, distribution, and oversight of contingency operations. Dispatchers in the LRS must quickly prepare schedules that meet the needs of their customers while dealing with real-world constraints, such as time windows, delivery priorities, and intermittent recurring missions. Currently, LRS vehicle operation elements are faced with a shortage of manpower and lack an efficient scheduling algorithm and tool. The purpose of this research is to enhance the dispatchers' capability to handle flexible situations and produce "good" schedules within current manpower restrictions. In this research, a new scheduling model and …

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Fuel-Air Injection Effects On Combustion In Cavity-Based Flameholders In A Supersonic Flow, William H. Allen Jr. Mar 2005

Fuel-Air Injection Effects On Combustion In Cavity-Based Flameholders In A Supersonic Flow, William H. Allen Jr.

Theses and Dissertations

The Air Force Research Lab, Propulsion Directorate, Wright-Patterson Air Force Base, Ohio has studied several designs regarding cavity flameholding for supersonic RAMJET (SCRAMJET) applications. The most recent of these studies have concluded that direct injection of ethylene fuel into the aft cavity ramp produced an efficient, robust flameholder given specific freestream condition and fuel flow rate. The main goals of this experiment are: 1) study the effect on combustion of direct fuel and air injection in the main flameholding cavity and 2) characterization of the operational limits (i.e., sustained combustion limits) over a variety of fuel and air flow rates. …

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Development Of A Higher-Order Upwind Algorithm For Compressible Fluid Flow, Barry A. Croker Mar 2005

Development Of A Higher-Order Upwind Algorithm For Compressible Fluid Flow, Barry A. Croker

Theses and Dissertations

A global fourth-order solution method that incorporates compact differencing with Roe's approximate Riemann solver was investigated. This method was incorporated into a one-dimensional numerical simulation of the compressible Euler equations, and applied to a one-dimensional shock tube problem. The method was also extended to two dimensions, and applied to a two-dimensional shock tube problem and an advecting vortical structure problem on both rectilinear and curvilinear meshes. The results were compared to a third-order Roe scheme and a fourth-order compact difference scheme. An order of accuracy determination showed that it has an order of accuracy somewhere near fourth order, with absolute …

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Entropy Generation As A Means Of Examining Continuum Breakdown, Christopher R. Schrock Mar 2005

Entropy Generation As A Means Of Examining Continuum Breakdown, Christopher R. Schrock

Theses and Dissertations

To quantify the validity and breakdown of the continuum equations of fluid flow, the concept of entropy generation is examined. This parameter is formulated utilizing statistical mechanics and kinetic theory to avoid the use of equilibrium assumptions. This analysis leads to expressions in terms of energy distribution functions. These results are applied to monatomic and diatomic molecules. A numerical procedure for computing these values using the Direct Simulation Monte Carlo Method (DSMC) is presented. Normal shock waves in argon and nitrogen were simulated at Mach numbers ranging from 1.2 to 10. Results are compared to Navier-Stokes predictions. The Navier-Stokes equations …

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A Study In Drag Reduction Of Close Formation Flight Accounting For Flight Control Trim Positions And Dissimilar Formations, Michael T. Morgan Mar 2005

A Study In Drag Reduction Of Close Formation Flight Accounting For Flight Control Trim Positions And Dissimilar Formations, Michael T. Morgan

Theses and Dissertations

This thesis further defines the position of greatest fuel savings benefit for the trail aircraft flying in a two-ship formation. The HASC95 vortex lattice code was used for the examination. Investigations of a similar formation of F-16 aircraft and a dissimilar formation of a lead KC-135 aircraft and a trail F-16 aircraft were conducted. The analyses determined the effects of varying airspeed on the optimal position. In addition, flight control surface deflections were taken into account during the analyses. Both investigations trimmed the aircraft in the yaw and roll axes to determine the optimal savings. The similar analysis was conducted …

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Validation Of Turbulence Models In The Beggar Code For Unsteady Flow, Kevin G. Storm Mar 2005

Validation Of Turbulence Models In The Beggar Code For Unsteady Flow, Kevin G. Storm

Theses and Dissertations

Validation of the turbulence models in the CFD code Beggar for unsteady turbulent flow are discussed. Six validation cases of the code are considered, three cases with the intent of validating the code without the turbulence model and three cases to validate the turbulence model itself. Finally, a more realistic simulation of a simplified store is examined. The turbulence models considered are the Baldwin-Lomax, Spalart-Allmaras, and a DES model. The conclusions made deal with necessary prerequisites to properly simulating unsteady turbulent flow and model selection. The prerequisites necessary in the Beggar code are a second order temporal discretization and the …

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The Use Of X-Ray Pulsars For Aiding Gps Satellite Orbit Determination, Dennis W. Woodfork Ii Mar 2005

The Use Of X-Ray Pulsars For Aiding Gps Satellite Orbit Determination, Dennis W. Woodfork Ii

Theses and Dissertations

This research proposes the use of an existing "signal of opportunity" - namely x-ray pulsars - to improve the accuracy and robustness of the GPS satellite and clock estimation algorithm. Improvement in satellite and clock accuracy results in a direct benefit to the user. A simulation has been developed to determine the effects of using x-ray pulsar measurements on the GPS Operational Control Segment. The epoch-specific position, velocity, and clock errors of all GPS satellites in the constellation were estimated using both pseudoranges and time-difference-of-arrival (TDOA) measurements from pulsars. The primary measure of accuracy is a constellation Signal-In-Space Range Error …

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Attitude Model Of A Reaction Wheel/Fixed Thruster Based Satellite Using Telemetry Data, Jason E. Smith Mar 2005

Attitude Model Of A Reaction Wheel/Fixed Thruster Based Satellite Using Telemetry Data, Jason E. Smith

Theses and Dissertations

Attitude determination of satellites is normally the job of inertial instruments, such as gyroscopes, or through sensing instruments, such as star trackers or Global Positioning Satellites (GPS). Satellite health monitoring systems watch and determine if the satellite deviates from its normal operating attitude orientation. Knowing the orientation of a satellite is essential in being able to control it in order to complete the satellite's designated mission. While there are a multitude of ways to determine a satellite's orientation, very little research has been done on determining if the attitude of a satellite can be determined directly from telemetry data of …

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Biaxial Fatigue Behavior Of Niti Shape Memory Alloy, Daniel M. Jensen Mar 2005

Biaxial Fatigue Behavior Of Niti Shape Memory Alloy, Daniel M. Jensen

Theses and Dissertations

Nitinol is a shape memory alloy (SMA) capable of martensite-to-austenite phase transformations enabling shape-memory behavior. Shape-memory properties make Nitinol a strong candidate material for use in aircraft applications such as actuators. Structural integrity and reliability of torque tube actuators must be assured before this material can be used in flight-critical components. Thorough understanding of the fatigue response of the material is essential for a structurally-sound SMA actuator design. The present effort investigates pure torsion and combined tension-torsion fatigue behavior of Nitinol at room temperature. Monotonic tests in tension and torsion were conducted to typify uni-directional stress-strain behavior. Fully-reversed torsion fatigue …

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Orbit Estimation Algorithms For A Microsatellite Rendezvous With A Non-Cooperative Target, John P. Heslin Mar 2005

Orbit Estimation Algorithms For A Microsatellite Rendezvous With A Non-Cooperative Target, John P. Heslin

Theses and Dissertations

This study investigated the minimum requirements to establish a satellite tracking system architecture for a microsatellite to rendezvous with a non-cooperative target satellite. A prototype optical tracking system was reviewed with emphasis on a proposed tactical employment that could be used by technologically unsophisticated state or non-state adversaries. With the tracking system architecture selected, simulated tracking data was processed with a Non-Linear Least Squares batch orbit estimation algorithm and a Bayes sequential orbit determination filter to update the target satellite's state vector.

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Noise Estimation In The Presence Of Bpsk Digital Burst Transmissions, Susan E. Bettison Mar 2005

Noise Estimation In The Presence Of Bpsk Digital Burst Transmissions, Susan E. Bettison

Theses and Dissertations

This research explores noise estimation techniques in an attempt to improve upon a previously developed digital burst transmission Binary Phase Shift Keyed (BPSK) demodulator. The demodulator success is dependent on the accuracy of the estimate of Power Spectral Density (PSD) of the unknown noise. Given a discrete time signal transformed into the frequency domain, the research seeks to determine if it is possible to effectively estimate the PSD of the unknown noise. The demodulator was developed using a new signal model for digital burst transmissions based on linear spectral subspace theory. Using this model and the redundancy properties of BPSK …

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Environmental Acoustic Transfer Functions And Filtering Acoustic Signals, Brandon P. Dias Mar 2005

Environmental Acoustic Transfer Functions And Filtering Acoustic Signals, Brandon P. Dias

Theses and Dissertations

Signal processing is the method of taking a given signal and extracting useful information, usually by a means of a transformation of some kind. Acoustic signals are functions of time in which the output is a pressure or a velocity potential response. An acoustic signal is affected by the environment in which it propagates, so one can attempt to remove the environmental effects to extract the useful information, in this case the original signal. This thesis will derive, in a mathematical framework, the process of filtering extraneous signals in a way that yields the original signal, and will then apply …

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Non-Adiabatic Energy Surfaces Of The B+H2 Systems, Lachlan T. Belcher Mar 2005

Non-Adiabatic Energy Surfaces Of The B+H2 Systems, Lachlan T. Belcher

Theses and Dissertations

In order to solve the dynamics of a system, the kinetic energy operator of the Hamiltonian must be diagonalized. Diagonalization requires rotation of the system into a non-adiabatic representation. This rotation is a coupling angle determined by the derivative coupling terms. Derivative coupling terms are calculated using Columbus and Brooklyn, software packages. Separation of internal dynamics characterized by Jacobi coordinates, and external dynamics characterized by a set of Euler angles and the center of mass position, requires a transformation from Cartesian coordinates to Jacobi coordinates required for subsequent dynamical calculations. Previous attempts to solve for non-adiabatic energy surfaces in this …

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Limitations In Time Resolved Photoluminescence Of Gallium Nitride Using A Streak Camera, Thomas R. Jost Mar 2005

Limitations In Time Resolved Photoluminescence Of Gallium Nitride Using A Streak Camera, Thomas R. Jost

Theses and Dissertations

Semiconductor performance is often characterized in terms of the rate at which its carrier recombination processes occur. Carrier recombination, including radiative, and Shockley-Read-Hall and Auger (both nonradiative), occurs at ultra-fast times in the picosecond or femtosecond regimes. A device which can measure both spectral data and temporal phenomena at this speed is the streak camera. The capability to do time-resolved spectroscopy of wide band gap semiconductors using a streak camera has been established at AFIT for the first time. Time resolved photoluminescence (TRPL) from samples of gallium nitride were measured at temperatures of 5 K over spectral bands of 36.6 …

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Detection Of Bacillus Spores By Aptamer Selectivity Using Atomic Force Microscopy, Nina M. Houtkooper Mar 2005

Detection Of Bacillus Spores By Aptamer Selectivity Using Atomic Force Microscopy, Nina M. Houtkooper

Theses and Dissertations

The anthrax attack of Oct 2001 demonstrates the need for a rapid detector for spores of Bacillus anthracis (BA). Current technology requires cultures of BA to be grown for 24 hours. Using aptamers, a type of nucleic acid ligand selective for a target molecule, to select BA spores for measurement without culturing is a possible solution for quicker detection. An aptamer having a specially selected structure is expected to selectively bind to the surface of its target spore, separating it from other material. An atomic force microscopy (AFM) method was developed to test this selectivity. Aptamers having structure selected to …

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Computational Model Of One-Dimensional Dielectric Barrier Discharges, Krista G. Marchand Mar 2005

Computational Model Of One-Dimensional Dielectric Barrier Discharges, Krista G. Marchand

Theses and Dissertations

As theory lags experiment for dielectric barrier discharge flow control, two different computational methods are implemented to give further insight into characteristics of the dielectric barrier discharge (DBD). A one-dimensional fluid model of a surface-type dielectric barrier discharge is created using He as the background gas. This simple model, which only considers ionizing collisions and recombination in the electropositive gas, creates an important framework for future studies into the origin of experimentally observed flow-control effects of the DBD. The two methods employed in this study include the semi-implicit sequential algorithm and the fully implicit simultaneous algorithm. The first involves consecutive …

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Modeling The Infrared Intensity Of A Large Commercial Aircraft, Ruben Martinez Mar 2005

Modeling The Infrared Intensity Of A Large Commercial Aircraft, Ruben Martinez

Theses and Dissertations

Measuring the infrared signature of large civilian aircraft has become increasingly important due to the proliferation of man-portable air defense systems (MANPADS) and the increasing threat of their use by terrorists. Because of the range of these shoulder-fired weapons, most aircraft flying over 20,000 feet are safe from the threat; however, aircraft taking-off or landing are extremely vulnerable. A radiometric model was developed to simulate a large commercial aircraft’s infrared intensity during these two critical phases of flight. The radiometric model was largely based on the dimensions of a Boeing 747-400 aircraft. It is capable of simulating elevation angles between …

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Electro-Optic Beam Steering Using Domain Engineered Lithium Tantalate, Daren J. Chauvin Mar 2005

Electro-Optic Beam Steering Using Domain Engineered Lithium Tantalate, Daren J. Chauvin

Theses and Dissertations

The operation of a 14-channel five stage electro-optic beam steering device was studied. Beam deflection scanned from 0° to 10.1° was demonstrated. The maximum angle is within 0.3% of design. Many laser systems in operation today implement mechanical beam steering methods that are often expensive in terms of cost, weight and power. They are slow and subject to wear and vibration. A non-inertial beam scanning mechanism, such as one based on the device studied in this research could enhance the performance of these systems. The device studied here is fabricated in LiTaO3 using micro-patterned domain reversal. The 14 channels …

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