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Air Force Institute of Technology

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Nuclear Forensics: Measurements Of Uranium Oxides Using Time-Of-Flight Secondary Ion Mass Spectrometry (Tof-Sims), Wesley A. Schuler Mar 2010

Nuclear Forensics: Measurements Of Uranium Oxides Using Time-Of-Flight Secondary Ion Mass Spectrometry (Tof-Sims), Wesley A. Schuler

Theses and Dissertations

Over the past decade, law enforcement, governmental and public agencies have been stymied by the threat of the trafficking of nuclear materials. During this time span, reports from the International Atomic Energy Agency of illicit trafficking have increased eightfold from 20 to 160. For this reason, nuclear forensics is a burgeoning science focused on the identification of seized special nuclear materials. Identification of these materials is based upon the wealth of information that can be obtained by applying multiple analytical and measurement technologies. All of the information gained from each sample can then be used to further characterize other samples …

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Hard Collisions In Rubidium Using Sub-Doppler Spectroscopy, Douglas E. Thornton Mar 2010

Hard Collisions In Rubidium Using Sub-Doppler Spectroscopy, Douglas E. Thornton

Theses and Dissertations

To better understand the laser kinetics of an alkali gain medium, hard collisions, or velocity-changing collisions, has been studied and a velocity-changing collisional rate has been calculated. Previous works have studied these collisions, but no rate has been calculated. Using the precise tool of sub-Doppler spectroscopy, atomic hard collisions can be observed. The collected spectra are fitted with two different line shapes to demonstrate the accuracy of this method. From the fits, the number of hard collisions can be extracted. The time scale of the hard collisions in rubidium is interpolated by varying the chopping frequency of the pump beam, …

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Attitude Control Of A Satellite Simulator Using Reaction Wheels And A Pid Controller, Ryan E. Snider Mar 2010

Attitude Control Of A Satellite Simulator Using Reaction Wheels And A Pid Controller, Ryan E. Snider

Theses and Dissertations

Attitude requirements of a satellite are determined by its mission: telecommunications, optical imagery, and meteorology to name a few. A satellite's ability to orient its mission critical hardware (solar arrays, attitude sensors, etc.), as well as its mission specific payload, is incumbent upon the performance of the satellite's attitude control system (ACS). For a highly accurate ACS and for moderately fast maneuverability, reaction wheels are preferred because they allow continuous and smooth control while inducing the smallest possible disturbance torques. The objective of this research is to design, build, test, and evaluate the performance of a reaction wheel ACS on-board …

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Knowledge Transformation In The United States Air Force Civil Engineer Career Field: A System Dynamics Approach, Gregory J. Ward Mar 2010

Knowledge Transformation In The United States Air Force Civil Engineer Career Field: A System Dynamics Approach, Gregory J. Ward

Theses and Dissertations

Recent operations in Iraq and Afghanistan have brought the level of expeditionary contractors to historically unprecedented levels, altering the work composition for military engineers. The alteration has shifted emphasis from technical knowledge areas toward managerial knowledge associated with supervising the increased number of contractors. This research utilizes System Dynamics modeling to analyze this shift in the United States Air Force Civil Engineer officer career field and resulting transformative effect on career field knowledge levels, both technical and managerial. The model is then tested with multiple external policy adjustments in the areas of career field structure, training, and operating policy. Results …

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Digital Delay Device, Guna Seetharaman, Paul E. Kladitis Mar 2010

Digital Delay Device, Guna Seetharaman, Paul E. Kladitis

AFIT Patents

A digitally controlled optical delay apparatus providing optical signal delays electrically selectable in the picosecond to nanosecond range by way of selectable signal path lengths. Path lengths are incremented in physical length and path delay time according to digital ratios. The delay element includes micro-miniature path changing mirrors controlled in path length selecting positioning by input signals of logic level magnitude. Fiber optic coupling of signals to and from the delay element and a combination of fixed position and movable mirror included optical signal path lengths are included.

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2009 Annual Report Of The Graduate School Of Engineering And Management, Air Force Institute Of Technology, Office Of Research And Sponsored Programs, Graduate School Of Engineering And Management, Afit Mar 2010

2009 Annual Report Of The Graduate School Of Engineering And Management, Air Force Institute Of Technology, Office Of Research And Sponsored Programs, Graduate School Of Engineering And Management, Afit

AFIT Documents

The Graduate School's Annual Report highlights research focus areas, new academic programs, faculty accomplishments and news, and provides top-level sponsor-funded research data and information.

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Air Force Institute Of Technology Research Report 2009, Office Of Research And Sponsored Programs, Graduate School Of Engineering And Management, Afit Feb 2010

Air Force Institute Of Technology Research Report 2009, Office Of Research And Sponsored Programs, Graduate School Of Engineering And Management, Afit

AFIT Documents

This report summarizes the research activities of the Air Force Institute of Technology’s Graduate School of Engineering and Management. It describes research interests and faculty expertise; lists student theses/dissertations; identifies research sponsors and contributions; and outlines the procedures for contacting the school. Included in the report are: faculty publications, conference presentations, consultations, and funded research projects. Research was conducted in the areas of Aeronautical and Astronautical Engineering, Electrical Engineering and Electro-Optics, Computer Engineering and Computer Science, Systems and Engineering Management, Operational Sciences, Mathematics, Statistics and Engineering Physics.

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Graduate School Of Engineering And Management 2010-2011 Catalog, Graduate School Of Engineering And Management, Air Force Institute Of Technology Jan 2010

Graduate School Of Engineering And Management 2010-2011 Catalog, Graduate School Of Engineering And Management, Air Force Institute Of Technology

AFIT Documents

The Graduate Catalog represents the offerings, programs, and requirements in effect at the time of publication.

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Large-Scale Distributed Coalition Formation, Daniel R. Karrels Dec 2009

Large-Scale Distributed Coalition Formation, Daniel R. Karrels

Theses and Dissertations

The CyberCraft project is an effort to construct a large scale Distributed Multi-Agent System (DMAS) to provide autonomous Cyberspace defense and mission assurance for the DoD. It employs a small but flexible agent structure that is dynamically reconfigurable to accommodate new tasks and policies. This document describes research into developing protocols and algorithms to ensure continued mission execution in a system of one million or more agents, focusing on protocols for coalition formation and Command and Control. It begins by building large-scale routing algorithms for a Hierarchical Peer to Peer structured overlay network, called Resource-Clustered Chord (RC-Chord). RC-Chord introduces the …

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Performance Analysis Of Live-Virtual-Constructive And Distributed Virtual Simulations: Defining Requirements In Terms Of Temporal Consistency, Douglas D. Hodson Dec 2009

Performance Analysis Of Live-Virtual-Constructive And Distributed Virtual Simulations: Defining Requirements In Terms Of Temporal Consistency, Douglas D. Hodson

Theses and Dissertations

This research extends the knowledge of live-virtual-constructive (LVC) and distributed virtual simulations (DVS) through a detailed analysis and characterization of their underlying computing architecture. LVCs are characterized as a set of asynchronous simulation applications each serving as both producers and consumers of shared state data. In terms of data aging characteristics, LVCs are found to be first-order linear systems. System performance is quantified via two opposing factors; the consistency of the distributed state space, and the response time or interaction quality of the autonomous simulation applications. A framework is developed that defines temporal data consistency requirements such that the objectives …

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Electromagnetic Field Control And Optimization Using Metamaterials, Jeffrey S. Mcguirk Dec 2009

Electromagnetic Field Control And Optimization Using Metamaterials, Jeffrey S. Mcguirk

Theses and Dissertations

Transformation optics has shown the ability to cloak an object from incident electromagnetic radiation is possible. However, the material parameters are inhomogeneous, anisotropic, and, in some instances, singular at various locations. In order for a cloak to be practically realized, simplified parameter sets are required. However, the simplified parameters result in a degradation in the cloaking function. Constitutive parameters for simplified two-dimensional cylindrical cloaks have been developed with two material property constraints. It was initially believed satisfying these two constraints would result in the simplified cylindrical cloaks having the same wave equation as an ideal cloak. Because of this error, …

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Discrete Film Cooling In A Rocket With Curved Walls, Jonathan F. Mccall Dec 2009

Discrete Film Cooling In A Rocket With Curved Walls, Jonathan F. Mccall

Theses and Dissertations

This study quantified the effects of discrete wall-based film cooling in a rocket with curved walls. Simulations and experiments showed decreasing with wall radius of curvature, holding jet diameter constant, improves net heat flux reduction (NHFR) and adiabatic effectiveness (η) for 90˚ compound injected cylindrical jets, though η is reduced at the highest curvature. NHFR and η improved further with a high favorable stream-wise pressure gradient (K=2.1x10-5) at all tested blowing ratios, but were affected little by a high density ratio (DR=1.76) using carbon dioxide as the coolant. Experiments were run at a Reynolds number of 31K and …

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Investigation Into Contact Resistance And Damage Of Metal Contacts Used In Rf-Mems Switches, Kevin W. Gilbert Dec 2009

Investigation Into Contact Resistance And Damage Of Metal Contacts Used In Rf-Mems Switches, Kevin W. Gilbert

Theses and Dissertations

This research examines the physical and electrical processes involved in lifecycle failure of Microelectromechanical (MEMS) Radio-Frequency (RF) cantilever beam ohmic contact switches. Failures of these switches generally occur at the contact, but complete details of performance of microcontacts are difficult to measure and have not been previously reported. This study investigated the mechanics of microcontact behavior by designing and constructing a novel experimental setup. Three representative contact materials of varying microstructure (Au, Au5%Ru, Au4%V2O5) were tested and parameters of contact during cycling were measured. The Au4%V2O5, a dispersion strengthened material developed at …

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An Empirical Methodology For Engineering Human Systems Integration, Nicholas S. Hardman Dec 2009

An Empirical Methodology For Engineering Human Systems Integration, Nicholas S. Hardman

Theses and Dissertations

The systems engineering technical processes are not sufficiently supported by methods and tools that quantitatively integrate human considerations into early system design. Because of this, engineers must often rely on qualitative judgments or delay critical decisions until late in the system lifecycle. Studies reveal that this is likely to result in cost, schedule, and performance consequences. This dissertation presents a methodology to improve the application of systems engineering technical processes for design. This methodology is mathematically rigorous, is grounded in relevant theory, and applies extant human subjects data to critical systems development challenges. The methodology is expressed in four methods …

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Heat And Current Propagation In Buffered Superconducting And Hyper-Conducting Wire, Jesse L. Lynn Dec 2009

Heat And Current Propagation In Buffered Superconducting And Hyper-Conducting Wire, Jesse L. Lynn

Theses and Dissertations

This research models and analyzes the distribution of heat and current in a buffered superconducting or hyper-conducting wire that shows potential for use in different capacities in multiple Air Force systems including the Active Denial System. The thesis includes a brief background of the reaction-diffusion system of partial differential equations provided by AFRL/RZPG and development of the numerical scheme. It then explores solutions to the model. These solutions indicate some of the various heat-related failures that may be observed in such a wire. The nature of the solutions observed depends on the characteristics of the wire, operating temperature and efficiency …

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Midwave Infrared Imaging Fourier Transform Spectrometry Of Combustion Plumes, Kenneth C. Bradley Dec 2009

Midwave Infrared Imaging Fourier Transform Spectrometry Of Combustion Plumes, Kenneth C. Bradley

Theses and Dissertations

A midwave infrared (MWIR) imaging Fourier transform spectrometer (IFTS) was used to successfully capture and analyze hyperspectral imagery of combustion plumes. Jet engine exhaust data from a small turbojet engine burning diesel fuel at a flow rate of 300 cm3/min was collected at 1 cm−1 resolution from a side-plume vantage point on a 200x64 pixel window at a range of 11.2 meters. Spectral features of water, CO, and CO2 were present, and showed spatial variability within the plume structure. An array of thermocouple probes was positioned within the plume to aid in temperature analysis. A single-temperature …

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Analysis Of Expedient Field Decontamination Methods For The Xmx/2l-Mil High-Volume Aerosol Sampler, Brandon C. Laroche Dec 2009

Analysis Of Expedient Field Decontamination Methods For The Xmx/2l-Mil High-Volume Aerosol Sampler, Brandon C. Laroche

Theses and Dissertations

The XMX/2L-MIL is a high volume air sampler used by the Air Force Bioenvironmental Engineering community to collect biological aerosols. Without a verified decontamination technique, however, the XMX cannot be used effectively. The objective of this study was to evaluate several proposed methods for expedient field decontamination of the XMX. This study centered on the inactivation of Bacillus atrophaeus spores and vegetative Erwinia herbicola organisms from the XMX inner canister. The goals in this investigation were twofold: 1) to verify the antimicrobial efficacy of a 10% bleach solution and 2) to determine if wiping the components with a bleach-soaked paper …

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Structured P2p Technologies For Distributed Command And Control, Daniel R. Karrels, Gilbert L. Peterson, Barry E. Mullins Dec 2009

Structured P2p Technologies For Distributed Command And Control, Daniel R. Karrels, Gilbert L. Peterson, Barry E. Mullins

Faculty Publications

The utility of Peer-to-Peer (P2P) systems extends far beyond traditional file sharing. This paper provides an overview of how P2P systems are capable of providing robust command and control for Distributed Multi-Agent Systems (DMASs). Specifically, this article presents the evolution of P2P architectures to date by discussing supporting technologies and applicability of each generation of P2P systems. It provides a detailed survey of fundamental design approaches found in modern large-scale P2P systems highlighting design considerations for building and deploying scalable P2P applications. The survey includes unstructured P2P systems, content retrieval systems, communications structured P2P systems, flat structured P2P systems and …

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Comparison Of Line-Peak And Line-Scanning Excitation In Two-Color Laser-Induced-Fluorescence Thermometry Of Oh, Stanislav Kostka, Sukesh Roy, Patrick J. Lakusta, Terrence Meyer, Michael W. Renfro, James R. Gord, Richard D. Branam Nov 2009

Comparison Of Line-Peak And Line-Scanning Excitation In Two-Color Laser-Induced-Fluorescence Thermometry Of Oh, Stanislav Kostka, Sukesh Roy, Patrick J. Lakusta, Terrence Meyer, Michael W. Renfro, James R. Gord, Richard D. Branam

Faculty Publications

Two-line laser-induced-fluorescence (LIF) thermometry is commonly employed to generate instantaneous planar maps of temperature in unsteady flames. The use of line scanning to extract the ratio of integrated intensities is less common because it precludes instantaneous measurements. Recent advances in the energy output of high-speed, ultraviolet, optical parameter oscillators have made possible the rapid scanning of molecular rovibrational transitions and, hence, the potential to extract information on gas-phase temperatures. In the current study, two-line OH LIF thermometry is performed in a well-calibrated reacting flow for the purpose of comparing the relative accuracy of various line-pair selections from the literature and …

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Dynamic Coalition Formation Under Uncertainty, Daylon J. Hooper, Gilbert L. Peterson, Brett J. Borghetti Oct 2009

Dynamic Coalition Formation Under Uncertainty, Daylon J. Hooper, Gilbert L. Peterson, Brett J. Borghetti

Faculty Publications

Coalition formation algorithms are generally not applicable to real-world robotic collectives since they lack mechanisms to handle uncertainty. Those mechanisms that do address uncertainty either deflect it by soliciting information from others or apply reinforcement learning to select an agent type from within a set. This paper presents a coalition formation mechanism that directly addresses uncertainty while allowing the agent types to fall outside of a known set. The agent types are captured through a novel agent modeling technique that handles uncertainty through a belief-based evaluation mechanism. This technique allows for uncertainty in environmental data, agent type, coalition value, and …

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Rc-Chord: Resource Clustering In A Large-Scale Hierarchical Peer-To-Peer System, Daniel R. Karrels, Gilbert L. Peterson, Barry E. Mullins Oct 2009

Rc-Chord: Resource Clustering In A Large-Scale Hierarchical Peer-To-Peer System, Daniel R. Karrels, Gilbert L. Peterson, Barry E. Mullins

Faculty Publications

Conducting data fusion and Command and Control (C2) in large-scale systems requires more than the presently available Peer-to-Peer (P2P) technologies provide. Resource Clustered Chord (RC-Chord) is an extension to the Chord protocol that incorporates elements of a hierarchical peer-to-peer architecture to facilitate coalition formation algorithms in large-scale systems. Each cluster in this hierarchy represents a particular resource available for allocation, and RC-Chord provides the capabilities to locate agents of a particular resource. This approach improves upon other strategies by including support for abundant resources, or those resources that most or all agents in the system possess. This scenario exists in …

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Precision Navigation Using Pre-Georegistered Map Data, Frederick C. Webber Sep 2009

Precision Navigation Using Pre-Georegistered Map Data, Frederick C. Webber

Theses and Dissertations

Navigation performance in small unmanned aerial vehicles (UAVs) is adversely affected by limitations in current sensor technology for small, lightweight sensors. Because most UAVs are equipped with cameras for mission-related purposes, it is advantageous to utilize the camera to improve the navigation solution. This research improves navigation by matching camera images to a priori georegistered image data and combining this update with existing image-aided navigation technology. The georegistration matching is done by projecting the images into the same plane, extracting features using the techniques Scale Invariant Feature Transform (SIFT) [5] and Speeded-Up Robust Features (SURF) [3]. The features are matched …

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Alternative Methods To Standby Gain Scheduling Following Air Data System Failure, Matthew W. Coldsnow Sep 2009

Alternative Methods To Standby Gain Scheduling Following Air Data System Failure, Matthew W. Coldsnow

Theses and Dissertations

The United States Air Force has advanced fighter aircraft that lose the ability to operate in a large portion of their operating flight envelope when an air data system failure is experienced. These aircraft are reverted to a fixed set of standby-gains that limit their maneuverability, degrade handling qualities, and increase susceptibility to departure. The purpose of this research was to determine if three alternative methods of standby-gain-scheduling could provide robust control with minimal performance degradation despite the lack of air data. To accomplish this, three methods of standby-gain-scheduling were developed, integrated, and tested in the Infinity Cube simulator at …

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F-16 Ventral Fin Buffet Alleviation Using Piezoelectric Actuators, Joseph S. Browning Sep 2009

F-16 Ventral Fin Buffet Alleviation Using Piezoelectric Actuators, Joseph S. Browning

Theses and Dissertations

Buffet-induced vibrations can have a disastrous impact on aircraft structures. Early attempts at combating buffet vibrations included passive methods such as structural enhancements and leading edge fences. Active methods have shown greater promise, including active airflow control, control surface modulation, and active structural control using piezoelectric actuators. Surface mounted piezoelectric actuators impart directional strain reducing the negative effects associated with harmful vibration. The Block-15 F-16 ventral fin represents an aircraft structure prone to failure when subjected to the buffet field from the wake of a LANTIRN pod. This research takes advantage of the susceptibility to buffet vibration of the Block …

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Least-Squares, Continuous Sensitivity Analysis For Nonlinear Fluid-Structure Interaction, Douglas P. Wickert Sep 2009

Least-Squares, Continuous Sensitivity Analysis For Nonlinear Fluid-Structure Interaction, Douglas P. Wickert

Theses and Dissertations

A least-squares, continuous sensitivity analysis method is developed for transient aeroelastic gust response problems to support computationally efficient analysis and optimization of aeroelastic design problems. A key distinction between the local and total derivative forms of the sensitivity system is introduced. The continuous sensitivity equations and sensitivity boundary conditions are derived in local derivative form which is shown to be superior for several applications. The analysis and sensitivity problems are both posed in a first-order form which is amenable to a solution using the least-squares finite element method. Several example and validation problems are presented and solved, including elasticity, fluid, …

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Thermo-Mechanical Characterization Of Silicon Carbide-Silicon Carbide Composites At Elevated Temperatures Using A Unique Combustion Facility, Ted T. Kim Sep 2009

Thermo-Mechanical Characterization Of Silicon Carbide-Silicon Carbide Composites At Elevated Temperatures Using A Unique Combustion Facility, Ted T. Kim

Theses and Dissertations

This research investigated four different types of CMCs in a simulated gas turbine engine hot section condition that involved the simultaneous application of a combustion environment and mechanical fatigue loading using a unique burner rig facility developed for this study at AFIT. Three of the materials were woven Melt-Infiltrated (MI) BN/SiC reinforced by Hi-Nicalon Type S (Hi-Nic-S), Sylramic (Syl) and Sylramic with insitu BN coating (Syl-iBN) fibers, respectively. They were made by the slurry cast method. The other CMC was MI Hi-Nic-S/BN/SiC made using the prepreg MI processing. Prepreg MI CMC and Sylramic-iBN fiber reinforced CMC showed better resistance to …

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Electronic Image Stabilization For Mobile Robotic Vision Systems, Michael John Smith Sep 2009

Electronic Image Stabilization For Mobile Robotic Vision Systems, Michael John Smith

Theses and Dissertations

When a camera is affixed on a dynamic mobile robot, image stabilization is the first step towards more complex analysis on the video feed. This thesis presents a novel electronic image stabilization (EIS) algorithm for small inexpensive highly dynamic mobile robotic platforms with onboard camera systems. The algorithm combines optical flow motion parameter estimation with angular rate data provided by a strapdown inertial measurement unit (IMU). A discrete Kalman filter in feedforward configuration is used for optimal fusion of the two data sources. Performance evaluations are conducted by a simulated video truth model (capturing the effects of image translation, rotation, …

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Signal Classification In Fading Channels Using Cyclic Spectral Analysis, Zhiqiang Wu, Eric C. Like, Vasu D. Chakravarthy, Paul Ratazzi Sep 2009

Signal Classification In Fading Channels Using Cyclic Spectral Analysis, Zhiqiang Wu, Eric C. Like, Vasu D. Chakravarthy, Paul Ratazzi

Student Publications

Cognitive Radio (CR), a hierarchical Dynamic Spectrum Access (DSA) model, has been considered as a strong candidate for future communication systems improving spectrum efficiency utilizing unused spectrum of opportunity. However, to ensure the effectiveness of dynamic spectrum access, accurate signal classification in fading channels at low signal to noise ratio is essential. In this paper, a hierarchical cyclostationary-based classifier is proposed to reliably identify the signal type of a wide range of unknown signals. The proposed system assumes no a priori knowledge of critical signal statistics such as carrier frequency, carrier phase, or symbol rate. The system is designed with …

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Synthesis, Interdiction, And Protection Of Layered Networks, Kevin T. Kennedy Sep 2009

Synthesis, Interdiction, And Protection Of Layered Networks, Kevin T. Kennedy

Theses and Dissertations

This research developed the foundation, theory, and framework for a set of analysis techniques to assist decision makers in analyzing questions regarding the synthesis, interdiction, and protection of infrastructure networks. This includes extension of traditional network interdiction to directly model nodal interdiction; new techniques to identify potential targets in social networks based on extensions of shortest path network interdiction; extension of traditional network interdiction to include layered network formulations; and develops models/techniques to design robust layered networks while considering trade-offs with cost. These approaches identify the maximum protection/disruption possible across layered networks with limited resources, find the most robust layered …

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Changes In Structural Health Monitoring System Capability Due To Aircraft Environmental Factors, Jeffrey D. Kuhn Sep 2009

Changes In Structural Health Monitoring System Capability Due To Aircraft Environmental Factors, Jeffrey D. Kuhn

Theses and Dissertations

Structural Health Monitoring (SHM) promises to decrease the maintenance cost and increase the availability of aging aircraft fleets by fundamentally changing the way structural inspections are performed. But this promise can only be realized through the consistent and predictable performance of a SHM system throughout the entire remaining life of an aircraft. In a sensor-based SHM system, sensor signal changes are analyzed and interpreted to identify structural flaws. But aircraft environmental factors such as temperature fluctuations, cyclic strain and exposure to various aircraft fluids also have the potential to change SHM sensor signals, raising questions about long term SHM system …

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