Engineering Commons^™

Modeling Application Of Hydrogen Release Compound To Effect In Situ Bioremediation Of Chlorinated Solvent-Contaminated Groundwater, Ryan C. Wood

Theses and Dissertations

This study investigates how application of Hydrogen Release Compound (HRC) might be implemented to remediate a site contaminated with tetrachloroethene (PCE) or its daughter products, under varying site conditions. The 3-D reactive transport model RT3D was coupled with a dual-Monod biodegradation submodel to simulate the effect of the hydrogen generated by HRC on accelerating the biodegradation of dissolved chlorinated solvents. Varying site conditions and injection well configurations were investigated to determine the effect of these environmental and design conditions on overall treatment efficiency. The model was applied to data obtained at a chlorinated solvent contaminated site at Vandenberg AFB, where …

An Investigation Of Geobase Mission Data Set Design, Implementation, And Usage Within Air Force Civil Engineer Electrical And Utilities Work Centers, Paul C. Loeber

Theses and Dissertations

In 2001, the Office of the Civil Engineer, Installation and Logistics, Headquarters, United States Air Force, (ILE) identified Civil Engineer Squadrons as the central point of contact for all base-level mapping requirements/activities. In order to update mapping methods and procedures, ILE has put into place a program called GeoBase, which uses private sector Geographic Information Systems (GIS) technology as a foundation. In its current state, GeoBase uses the concept of a "Common Installation Picture (CIP)" to describe the goal of a consolidated "visual" that integrates the many layers of mapping information. The CIP visual is formed from a collection of …

An Historical Analysis Of Factors Contributing To The Emergence Of The Intrusion Detection Discipline And Its Role In Information Assurance, James L.M. Hart

Theses and Dissertations

In 2003, Gartner, Inc., predicted the inevitable demise of the intrusion detection (ID) market, a major player in the computer security technology industry. In light of this prediction, IT executives need to know if intrusion detection technologies serve a strategic purpose within the framework of information assurance (IA). This research investigated the historical background and circumstances that led to the birth of the intrusion detection field and explored the evolution of the discipline through current research in order to identify appropriate roles for IDS technology within an information assurance framework. The research identified factors contributing to the birth of ID …

An Analysis Of Information Assurance Relating To The Department Of Defense Radio Frequency Identification (Rfid) Passive Network, Robert G. Giovannetti

Theses and Dissertations

The mandates for suppliers to commence Radio Frequency Identification tagging set by Wal-Mart and the Department of Defense is changing this long-time rumored technology into reality. Despite the many conveniences to automate and improve asset tracking this technology offers, consumer groups have obstinately opposed this adoption due to the perceived weaknesses in security and privacy of the network. While the heated debate between consumers and retailers continues, little to no research has addressed the implications of security on the Department of Defense Radio Frequency Identification network. This thesis utilized a historical analysis of Radio Frequency Identification literature to determine whether …

Investigation Of Aerobraking To Return The Space Maneuver Vehicle To Low Earth Orbit From Geotransfer Orbit, Benjamin M. Berlin

Theses and Dissertations

This study investigated the use of ballistic and Double-Dip'' aerobraking reentry to return the Space Maneuver Vehicle (SMV) from geotransfer orbit in no more than two atmosphere passes. Lift and drag accelerations were applied to the two-body problem when either of their magnitudes exceeded 1/1000 g. Lift and drag coefficients, along with the SMV model, were taken from Investigation of Atmospheric Reentry for the Space Maneuver Vehicle by Captain McNabb, AFIT/GA/ENY/04-M03. Target perigees were formulated using the two-body problem. The orbit from each target perigee was numerically integrated around a planar earth model using a fourth order Runge-Kutta method. Ballistic …

Effectively Managing The Air Force Enterprise Architecture, Jamie P. Sharkey

Theses and Dissertations

The Air Force is developing and implementing an enterprise architecture to meet the Clinger-Cohen Act's requirement that all federal agencies use an architecture to guide their information technology (IT) investments. However, this act does not provide guidance on how to effectively manage an enterprise architecture. Prior research applied maturity models and competency stages to manage an enterprise architecture by defining layers of enterprise architecture management maturity. However, these efforts tend to view enterprise architecture development as a one-time planning process rather than an iterative progression. Enterprise architecture is not a one-time exercise, but rather it is an on-going effort within …

Passwords: A Survey On Usage And Policy, Kurt W. Martinson

Theses and Dissertations

Computer password use is on the rise. Passwords have become one of the primary authentication methods used today. It is because of their high use that organizations have started to place parameters on passwords. Are password restrictions a nuisance? What are some of the consequences that result as organizations place the burden of their computer security on passwords? This thesis analyzes the results of a survey instrument that was used to determine if individuals are using similar techniques or patterns when choosing or remembering their passwords. It also looks at how individuals feel about using passwords. In addition, the authors …

The Feasibility Of The U.S. Air Force Mandating The Exclusive Use And Purchase Of Forest Stewardship Council Certified Wood And Paper Containing 100% Post Consumer Content, Silinda Johnson

Theses and Dissertations

The Resource Conservation and Recovery Act required federal agencies to purchase products with the highest recovered content (or post-consumer content in the case of paper) as practicable. The Office of Federal Procurement Policy required all executive agencies to give preference in their procurement programs to products that conserve natural resources and protect the environment. These requirements necessitate that the Air Force consider purchasing 100% post-consumer content (PCC) paper and Forest Stewardship Council (FSC) certified wood because of their environmentally preferable attributes. This study compared the availability, performance standards, and prices of 100% PCC paper to 30% PCC paper and FSC-certified …

Project Portfolio Management: An Investigation Of One Air Force Product Center, Bryan D. Edmunds

Theses and Dissertations

Over the last two decades, reducing product development times in the DoD has been the focus of many committees, commissions, and research efforts. Despite the implementation of numerous recommendations, the DoD still struggles with long acquisition cycle times. This research is part of the Air Force Cycle Time Reduction Research Program (CTRRP), which grew out of the Cycle Time Reduction Action Plan, developed in 1998. This research focuses on the portfolio management (project selection and resource allocation) part of the CTRRP. The purpose of this research effort was to investigate the use of portfolio management within the Air Force. Specifically, …

Daytime Detection Of Space Objects, Alistair D. Funge

Theses and Dissertations

Space Situational Awareness (SSA) requires repeated object updates for orbit accuracy. Detection of unknown objects is critical. A daytime model was developed that evaluated sun flares and assessed thermal emissions from space objects. Iridium satellites generate predictable sun glints. These were used as a model baseline for daytime detections. Flares and space object thermal emissions were examined for daytime detection. A variety of geometric, material and atmospheric characteristics affected this daytime detection capability. In a photon noise limited mode, simulated Iridium flares were detected. The peak Signal-to- Noise Ratios (SNR) were 6.05e18, 9.63e5, and 1.65e7 for the nighttime, daytime and …

Performance Based Service Acquisition: A Quantitative Evaluation Of Implementation Goals And Performance In The United States Air Force, Dylan D. Pope

Theses and Dissertations

In an attempt to maximize cost savings in the rapidly growing services sector, the DoD established a Performance Based Service Acquisition (PBSA) strategy that focuses on evaluating contractor performance based on their ability to meet desired outcomes rather than the means to which the outcomes are obtained. In April 2000, Dr. Gansler, then Under Secretary of Defense for Acquisition, Technology and Logistics, mandated that 50 percent of all eligible service acquisitions be awarded using PBSA methods by FY 2005. Since then very little research has been focused on USAF implementation of PBSA and the progress and attainment of the PBSA …

Enabling Intrusion Detection In Ipsec Protected Ipv6 Networks Through Secret-Key Sharing, Patrick J. Sweeney

Theses and Dissertations

As the Internet Protocol version 6 (IPv6) implementation becomes more widespread, the IP Security (IPSec) features embedded into the next-generation protocol will become more accessible than ever. Though the network-layer encryption provided by IPSec is a boon to data security, its use renders standard network intrusion detection systems (NIDS) useless. The problem of performing intrusion detection on encrypted traffic has been addressed by differing means with each technique requiring one or more static secret keys to be shared with the NIDS beforehand. The problem with this approach is static keying is much less secure than dynamic key generation through the …

Performance Of A Spectrally Encoded Multi-Carrier Phase Shift Keying Communications System In A Frequency-Selective, Slowly-Fading Multipath Channel, Charles M. Gaona

Theses and Dissertations

This research examines the performance of a spectrally encoded, multi-carrier, phase shift keying communications system in a frequency-selective, slowly-fading multipath channel. The specific communications system modeled is the transform domain communication system (TDCS) originally researched as an interference avoidance technique. Previous TDCS research assumed an additive white Gaussian noise channel, which is not representative of a realistic environment. This thesis presents overviews of previous TDCS research, the multipath fading channel, and the RAKE receiver. Analysis and Matlab simulations compare the performance of spectrally encoded and un-encoded signals through a multipath fading channel using an L-diversity TDCS RAKE receiver. Encoded signals …

Head Tracking For 3d Audio Using A Gps-Aided Mems Imu, Jacque M. Joffrion

Theses and Dissertations

Audio systems have been developed which use stereo headphones to project sound in three dimensions. When using these 3D audio systems, audio cues sound like they are originating from a particular direction. There is a desire to apply 3D audio to general aviation applications, such as projecting control tower transmissions in the direction of the tower or providing an audio orientation cue for VFR pilots who find themselves in emergency zero-visibility conditions. 3D audio systems, however, require real-time knowledge of the pilot's head orientation in order to be effective. This research describes the development and testing of a low-cost head …

Finite Difference Time Domain (Fdtd) Analysis Of A Leaky Traveling Wave Microstrip Antenna, Gregory M. Zelinski

Theses and Dissertations

This thesis provides the groundwork that will enable the development of a lightweight, inexpensive, aerodynamic, and broadband antenna. Whether for radar or communication, an antenna with these properties would be a force multiplier for the smaller, limited payload air vehicles the United States Air Force will pursue in the coming years. Several microstrip antennas using the first higher order mode were simulated with the Finite-Difference Time-Domain (FDTD) method. The propagation constant of each antenna was extracted from the resulting field distribution for comparison with a transverse resonance approximation, measured far-field patterns, and other simulated antennas. Variations of the geometry were …

Doppler Aliasing Reduction In Wide-Angle Synthetic Aperture Radar Using A Linear Frequency Modulated Random Stepped-Frequency Waveform, Jason R. Mcmahon

Theses and Dissertations

This research examines the theory, application, and results of using Random Stepped-Frequency (RSF) waveforms to mitigate Doppler aliasing in a wide-angle Synthetic Aperture Radar (SAR) imaging scenario. Severe Doppler aliasing typically occurs in this scenario since range extent requirements force the pulse repetition frequency to a value violating the lower bound for Doppler aliasing. Building on previous research, this work expands upon RSF waveform analysis using a Linear Frequency Modulated RSF (LFM-RSF) waveform. The RSF waveform suppresses Doppler aliasing by positioning nulls at the aliased scatterer location. Applying LFM with RSF processing theoretically provides greater frequency coverage and aliased scatterer …

Three-Dimensional Finite Element Modeling As A Tool For Flexible Pavement Design And Analysis, Michael L. Willis

Theses and Dissertations

This study investigates the potential of using finite element modeling for analyzing the performance of flexible pavement. The study is deemed necessary because of the complexity of the landing gears and heavy loads imposed by heavier and bigger aircraft, like the Boeing 747-400, Airbus A380 and Boeing 777.

The development of the finite element model required a finite element mesh design study and two verification studies conducted to show that the material properties and material models used in the study gave a good representation of the individual soil and also the response of the pavement structure.

The dynamic analysis which …

Photocontrol Data Acquisition System For Lamp Life Prediction In High Pressure Sodium Lighting, Jeffrey William Tisa

Theses and Dissertations

This thesis begins with a brief historical account of high intensity discharge (HID) lighting. It begins in the seventeenth century and concludes with the modem high pressure sodium (HPS) lamp, which has become the most widespread HID lighting source due to its high efficacy (Lumens/Watt) and acceptable color rendition. Following a more in-depth discussion on the HPS lamp, a means of estimating the arc tube voltage of an HPS lamp from the confines of a photocontrol is introduced. This technique is implemented as part of a 'smart' photocontrol data acquisition unit that functions as part of a proposed practical asset …

Optimization Of Shape, Size, And Topology Design Variables In Trusses With A Genetic Algorithm, Kevin M. Gillman

Theses and Dissertations

Briggs' genetic algorithm was extended in the Gillman algorithm to include shape optimization of trusses. Other contributions include value representation, different member linking, alternate genes, automatic k-factor evaluation for buckling, and the option to prevent overlapping members. The purpose of these contributions was to make optimization using a genetic algorithm more accessible to design engineers. The Gillman algorithm was demonstrated in two original examples as well as an example from a published work. The Gillman algorithm was effective in finding lighter designs.

Computer-Simulation-Assisted Lean Manufacturing Training, Luoding Wang

Theses and Dissertations

This thesis assesses the potential of using computer simulation to aid existing lean manufacturing training methods such as lecture and live simulation. An investigation of this possibility was carried out in conjunction with UMEP's Lean 101 class. In the study, two experimental computer simulation models demonstrating the push and pull production scenarios were constructed using ProModel software. Simulation models were equipped with a Visual Basic interface to aid trainees to manipulate the model via ActiveX. Constructed computer simulation was compared with live simulation to answer these research questions: 1. Was computer simulation able to teach additional lean concepts not covered …

Comprehensive Black Liquor Droplet Combustion Studies, Leong-Teng Ip

Theses and Dissertations

Black liquor, a byproduct from pulp production, is burned in a recovery boiler to generate electricity and recover inorganic materials. Black-liquor-droplet combustion is fundamental to understanding and potentially improving recovery boiler performance. This investigation reports comprehensive experimental data collected for a suite of five liquors. All the data were collected with newly-designed laboratory equipment, several aspects of which are unique. Single droplets were suspended on a thermocouple and heated in a furnace. Simultaneous diameter (size and shape), internal and surface temperatures, surface emissivity, and mass were measured under various furnace temperatures and gas compositions. The images recorded by the cameras …

Dynamic Reconfigurable Machine Tool Controller, Wei Li

Theses and Dissertations

This dissertation presents a dynamic reconfigurable control strategy based on the Direct Machining And Control (DMAC) research at Brigham Young University. A reconfigurable framework is proposed which will allow a machine tool to be controlled by a variety of applications and control laws. This Reconfigurable Mechanism for Application Control (RMAC) paradigm uses a hierarchical architecture to configure a mechanism into a device driver for direct control by an application like CAD/CAM. The RMAC paradigm is one of a mechanism device driver assigned to each mechanism class or model, and uses only the master model to control the mechanism. The traditional …

Engineering Tools For Variable Stiffness Vibration Suppression And Isolation, Michael F. Winthrop

Theses and Dissertations

With the advent of smart materials, the concept of semi-active control or dynamic control of stiffness and/or damping for vibration control of structures has become practical and has seen limited use. Semi-active control has advantages over active and passive control methods, since it provides almost as much capability as active control while requiring much less power. Its main disadvantage is its inherent nonlinearity, greatly complicating engineering design. The purpose of this research is to extend semi-active control vibration isolation tools and methods considering space launch and on-orbit systems.

Performance Of Concrete Bridge Deck Joints, Lik Hang Yuen

Theses and Dissertations

The purpose of this research was to identify the types of joints available for use on concrete bridge decks and to investigate the performance characteristics of each type, including primary functions and movement ranges. Eleven reports on joint performance published by state departments of transportation and universities nationwide were analyzed in order to obtain information on joint performance problems typically encountered by state transportation agencies. In addition, test methods and specifications provided by the American Society for Testing and Materials (ASTM) were reviewed for application by bridge engineers to ensure the adequacy of deck joints.

The research indicates that compression …

The Effect Of Post-9/ 11 Security Requirements On Aviation Higher Education And Aviation Higher Education Student Attitudes Toward The United States, Richard G. Ham, Sr.

Theses and Dissertations

This study investigates the effect of security measures implemented as a result of the terrorist attacks of September 11, 2001 on aviation higher education and how the measures affected aviation higher education students' attitudes toward the United States. The underlying premise of the study is that international persistence represents the ultimate indicator of economic and cultural effect on higher education while international student attitudes provide insight into possible causes of eroding international relationships that lead to terrorism. This is a sequential mixed methods study using a qualitative interview pilot study as the foundation, followed by a quantitative survey and ending …

Experimental Design And Analysis Of Piezoelectric Synthetic Jets In Quiescent Air, Poorna Mane

Theses and Dissertations

Flow control can lead to saving millions of dollars in fuel costs each year by making an aircraft more efficient. Synthetic jets, a device for active flow control, operate by introducing small amounts of energy locally to achieve non-local changes in the flow field with large performance gains. These devices consist of a cavity with an oscillating diaphragm that divides it, into active and passive sides. The active side has a small opening where a jet is formed, whereas and the passive side does not directly participate in the fluidic jet.Research has shown that the synthetic jet behavior is dependent …

The Effects Of Parkinson's On Fixational Stability, Erin L. Mallahan

Theses and Dissertations

Parkinson's disease (PD) is a progressive, neurological movement disorder. The stability of eye movements in PD is not well understood but many patients report difficulty doing tasks that require stabilized fixation and gaze. The ability to stabilize an image on the retina is critical is acquiring visual information. The purpose of this study was to compare the stability of fixational eye movements of PD patients to those of age-matched controls. Eye movements during simple fixation tasks were recorded from 66 subjects (ages 52 to 84), and 36 age-matched controls (ages 58-85). The absolute velocity of the fixational eye movements were …

The Use Of Computerized Dynamic Posturography To Assess The Balance In Individuals With Parkinson's Disease, Theresa Erin Mcguirk

Theses and Dissertations

Postural instability is one of the hallmarks of Parkinson's disease (PD), currently evaluated using several subjective tools. However, the nature and degree of the resulting balance deficit is not well specified by these tools. Computerized dynamic posturography (CDP) provides an objective assessment by isolating and quantifying sensory and motor contributions to balance control. The purpose of this study was to compare balance in individuals with PD to a control group using CDP (NeuroCom Smart Balance Master® system). Testing took place at the Southeast Parkinson's disease Research Education and Clinical Center (PADRECC), an interdisciplinary center of excellence for people with PD …

Iterative Methods For The Reconstruction Of Tomographic Images With Unconventional Source-Detector Configurations, Abey Mukkananchery

Theses and Dissertations

X-ray computed tomography (CT) holds a critical role in current medical practice for the evaluation of patients, particularly in the emergency department and intensive care units. Expensive high resolution stationary scanners are available in radiology departments of most hospitals. In many situations however, a small, inexpensive, portable CT unit would be of significant value. Several mobile or miniature CT scanners are available, but none of these systems have the range, flexibility or overall physical characteristics of a truly portable device. The main challenge is the design of a geometry that optimally trades image quality for system size. The goal of …

Numerical Modeling Of Synthetic Jets In Quiescent Air With Moving Boundary Conditions, Nicholas D. Castro

Theses and Dissertations

Flow control is a key factor in optimizing the performance of any vehicle moving through fluids. Particularly, in aerodynamics there are many potential benefits for implementing synthetic jets to achieve aircraft designs with less moving parts, uper- maneuverability, and separation control for fuel economy. Piezoelectric synthetic jets are of special interest because of their lightweight and low power consumption. Numerous publications on such jets are available. Actuator properties and boundary conditions relevant to this particular application however are often overlooked. The focus of this project is to numerically model synthetic jets in quiescent air to study the influence of cavity …