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Award Term Incentive Contracting: An Investigation Of United States Air Force Strategic Purchasing, Rachael A. Harris Mar 2001

Award Term Incentive Contracting: An Investigation Of United States Air Force Strategic Purchasing, Rachael A. Harris

Theses and Dissertations

This research explored implementing a best commercial practice of establishing strategic purchasing relationships within the Department of Defense (DOD) procurement environment. The research was sparked by Air Force Material Command's (AFMC) instituting a commercial style acquisition strategy using an award term incentive on several programs. The award term incentive provides for extensions or reductions to the term of the contract based on contractors' level of performance. Forthcoming implementation of Air Force FAR supplement 5317.7X Incentive Term Extension, will likely increase the number of acquisitions using an award term incentive. Research findings indicate that management should consider expanding the AFMC award …

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Development And Testing Of A Multiple Filter Approach For Precise Dgps Positioning And Carrier-Phase Ambiguity Resolution, Paul E. Henderson Mar 2001

Development And Testing Of A Multiple Filter Approach For Precise Dgps Positioning And Carrier-Phase Ambiguity Resolution, Paul E. Henderson

Theses and Dissertations

The most precise relative positioning obtained using differential GPS depends on accurately determining carrier-phase integer ambiguities. To achieve high precision, many current static and kinematic algorithms use a floating-point solution until enough information becomes available to fix the carrier-phase ambiguities accurately. A mew method is presented that uses a multiple model Kalman filter to resolve the carrier-phase integer ambiguities. This method starts with the floating-point results, yet smoothly and rapidly attains the precision of the correct fixed-integer solution, eliminating the need to decide when to switch from the floating to the fixed-integer solution. This method is based on a theoretically …

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Factors Influencing The Air Force Cycle Ergometry Fitness Assessment, Heather M. Hunn Mar 2001

Factors Influencing The Air Force Cycle Ergometry Fitness Assessment, Heather M. Hunn

Theses and Dissertations

This research investigated the influence of exercise activities, situational factors, and personality on the Air Force submaximal cycle ergometry test (SCET). Data were collected via a questionnaire administered to 209 active duty students and faculty assigned to the Air Force Institute of Technology during their required annual SCET. Stepwise multiple regression and ANOVA were used to find the proportion of variance explained by the significant predictors of SCET results for various subsets of the sampled population. For the group as a whole, self-reported test anxiety explained 24% of the variance in SCET results, while reported aerobic caloric expenditure during exercise …

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Multiple Model Adaptive Estimation For Time Series Analysis, Ibrahim Dulger Mar 2001

Multiple Model Adaptive Estimation For Time Series Analysis, Ibrahim Dulger

Theses and Dissertations

Multiple Model Adaptive Estimation (MMAE) is a Bayesian technique that applies a bank of Kalman filters to predict future observations. Each Kalman filter is based on a different set of parameters and hence produces different residuals. The likelihood of each Kalman filter's prediction is determined by a magnitude of the residuals. Since some researchers have obtained good forecasts using a single Kalman filter, we tested MMAE's ability to make time series predictions. Our Kalman filters have a dynamics model based on a Box-Jenkins Auto-Regressive Moving Average (ARMA) model and a measure model with additive noise. The time-series prediction is based …

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Turbine Blade Surface Roughness Effects On Shear Drag And Heat Transfer, Jess W. Drab Mar 2001

Turbine Blade Surface Roughness Effects On Shear Drag And Heat Transfer, Jess W. Drab

Theses and Dissertations

This work used scaled samples of actual turbine blade surfaces to characterize correlations between turbine surface roughness, friction coefficient, and convective heat transfer rate-parameters which affect an engine's efficiency and the blade's lifespan. For erosion/deposits, friction coefficients up to 250 times higher and convective heat transfer coefficients of up to 150 times higher were found when compared to a flat plate baseline. Other roughness types (pitting and fuel deposits) yielded less dramatic results. These results did not follow existing friction coefficient-to-heat transfer coefficient correlations, such as the Reynolds analogy. While these analytical and empirical correlations hold for flat plates, they …

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Dissolution Of Chromium From Inhalable Primer Paint Particles Into A Simulated Lung Fluid, David A. Kauth Mar 2001

Dissolution Of Chromium From Inhalable Primer Paint Particles Into A Simulated Lung Fluid, David A. Kauth

Theses and Dissertations

The use of chromate as a corrosion inhibitor in primer paint is an essential component for the protection of aluminum-skinned aircraft and the primary source of hexavalent chromium (Cr (VI)) exposure to USAF aircraft painters. The objective of this research was to quantify the dissolution of chromate from freshly sprayed paint particles into a simulated lung fluid (SLF). Two primer paints were sprayed with a paint spray gun to generate overspray particles for collection into impingers filled with SLF. Particles were allowed to soak in SLF for 24 and 48 hours and then the particles were removed by centrifugation. The …

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Validation And Characterization Of Ionospheric Densities Measured By Dmsp, Herbert L. Keyser Mar 2001

Validation And Characterization Of Ionospheric Densities Measured By Dmsp, Herbert L. Keyser

Theses and Dissertations

Future models of the thermosphere-ionosphere-magnetosphere system will require near real-time assimilation of ionospheric parameters to specify% and forecast these regions One of the current sensors that will be used in the GAIM model is the DMSP SSIES. Knowledge of the SSIES's reliability and data characteristics is key to using the data when relying on automated processes to ingest the data. To validate the DMSP value, the DMSP-measured density is compared to ground-based ISR measurements from solar minimum to solar maximum. The DMSP data are compared to data from the ISRs located at the Millstone Hill Observatory in Massachusetts and Sondrestrom …

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An Objective Evaluation Of Four Sar Image Segmentation Algorithms, Jason B. Gregga Mar 2001

An Objective Evaluation Of Four Sar Image Segmentation Algorithms, Jason B. Gregga

Theses and Dissertations

Because of the large number of SAR images the Air Force generates and the dwindling number of available human analysts, automated methods must be developed. A key step towards automated SAR image analysis is image segmentation. There are many segmentation algorithms, but they have not been tested on a common set of images, and there are no standard test methods. This thesis evaluates four SAR image segmentation algorithms by running them on a common set of data and objectively comparing them to each other and to human segmentors. This objective comparison uses a multi-metric a approach with a set of …

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Influence Of Personality Type And Anonymity On Participation In A Group Support System, Robert E. Hartmann Mar 2001

Influence Of Personality Type And Anonymity On Participation In A Group Support System, Robert E. Hartmann

Theses and Dissertations

A group support system (GSS) uses a combination of networked personal computers, software that collects, manipulates, and aggregates member's individual input, and human facilitation to improve the group decision-making process. A GSS has been promoted as a means of improving the quantity and quality of ideas within a decision-making meeting. Research into GSS has focused on the benefits of providing anonymity to improve participation. Anonymity in a GSS meeting has been offered as a means to improve participation, which in turn improves decision quality. To date this has not been proven through research. In fact, there is conflicting evidence as …

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Modeling Biodegradation Of Chlorinated Groundwater Contaminants Under Iron-Reducing Conditions Of A Constructed Wetland: A System Dynamics Approach, Max E. Johnson Mar 2001

Modeling Biodegradation Of Chlorinated Groundwater Contaminants Under Iron-Reducing Conditions Of A Constructed Wetland: A System Dynamics Approach, Max E. Johnson

Theses and Dissertations

The purpose of this study is to determine and explore the fundamental processes associated with biodegradation of chlorinated ethenes in iron-reducing conditions of a constructed wetland and to evaluate the impacts of changing conditions (both natural and engineer-controlled) on the system. The modeler uses a system dynamics approach to construct a model that represents behavior in the iron-reducing environment. The model incorporates hematite, a form of oxidized iron (Fe3+), as the electron acceptor in microbial biodegradation in the system. Vinyl chloride, cis-dichloroethene, and trans-dichloroethene are known to anaerobically degrade to carbon dioxide in the presence of oxidized iron. …

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Routing Of Time-Sensitive Data In Mobile Ad Hoc Networks, Necdet Kilic Mar 2001

Routing Of Time-Sensitive Data In Mobile Ad Hoc Networks, Necdet Kilic

Theses and Dissertations

This research focuses on routing of time-sensitive data in mobile ad hoc networks. Routing protocols that were developed for ad hoc networks have been reviewed. Ad Hoc On-demand Distance Vectoring (AODV) routing protocol, which is a prominent routing protocol among these protocols have been implemented in OPNET, a discrete-event simulation tool. Taking AODV as a point of departure, a routing protocol named Real Time Routing Protocol (RTRP) has been developed and also implemented in simulation environment. The performance of these routing protocols have been observed by simulating them in various experiments where the workload has been chosen to be time-sensitive …

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Differences In Civil Engineer Perceptions Of Change Based On Prior Training And Experience, Steven W. Lo Mar 2001

Differences In Civil Engineer Perceptions Of Change Based On Prior Training And Experience, Steven W. Lo

Theses and Dissertations

The Department of Defense (DoD) and the United States Air Force (USAF) have moved toward an aggressive stance to competitively source and privatize (CS&P) support functions as much as possible. This move is intended to shrink support costs and redirect the savings to force and equipment modernization. In addition, the USAF hopes to realize improved services, gain access to technology, share risks with contractors, and allow its forces to focus on the core competencies. In order to implement OS&P, the USAF communicates information through two major pathways, passive and active. Passive communication is similar to traditional classroom learning where information …

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Malicious Hackers: A Framework For Analysis And Case Study, Laura J. Kleen Mar 2001

Malicious Hackers: A Framework For Analysis And Case Study, Laura J. Kleen

Theses and Dissertations

Recent years have seen an increase in the number and severity of Information Operations (IO) attacks upon DoD resources. At a higher level, the US as a whole has come under cyber attack by individuals and groups seeking thrills, monetary gain, publicity for their causes, and myriad other goals. This effort develops a first cut model of individual hacker mentality that can be utilized to improve threat assessment, mitigate Information Assurance (IA) vulnerabilities, and improve risk assessment. Further, it is a first step toward automated characterization of Information Warfare (IW) attacks based upon hacker types. All hackers are not the …

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Requirements-Based Methodology For Determining Age Inventory Levels, James A. Mackenna Mar 2001

Requirements-Based Methodology For Determining Age Inventory Levels, James A. Mackenna

Theses and Dissertations

The purpose of this research was to illuminate crucial areas in analyzing AGE needs on an operational flightllne and assist in determination of AGE inventory levels. Further refinements could result in more objective and accurate assessments of actual flightline AGE needs and associated risks involved with reduction of AGE inventory levels. The research in this thesis consists of a discrete event simulation to determine desired AGE inventory level through an analysis of aircraft launches and wait time for AGE support by varying AGE (mean time between failure) MTBF and AGE inventory. Stochastic inputs for aircraft failures, AGE delivery times, and …

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A Methodology For Simulating The Joint Strike Fighter's Prognostics And Health Management System, Michael E. Malley Mar 2001

A Methodology For Simulating The Joint Strike Fighter's Prognostics And Health Management System, Michael E. Malley

Theses and Dissertations

The Autonomic Logistics System Simulation (ALSim) model was developed to provide decision makers a tool to make informed decisions regarding the Joint Strike Fighter's (JSF) Autonomic Logistics System (ALS). The ALS provides real-time maintenance information to ground maintenance crews, supply depots, and air planners to efficiently manage the availability of JSF aircraft. This thesis effort focuses on developing a methodology to model the Prognostics and Health Management (PHM) component of ALS. The PHM component of JSF monitors the aircraft status. To develop a PHM methodology to use in ALSim a neural network approach is used. Notional JSF prognostic signals were …

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The Effect Of Improving The Logistics Pipeline On Supply Support Of Aerospace Expeditionary Forces, Steven L. Martinez Mar 2001

The Effect Of Improving The Logistics Pipeline On Supply Support Of Aerospace Expeditionary Forces, Steven L. Martinez

Theses and Dissertations

One of the biggest considerations for an Aerospace Expeditionary Force (AEF), in terms of cost and airlift requirement, is the use of aircraft spares kits to support combat operations. To date, these kits are built on the assumption that there would be no resupply for the first 30 days of a contingency. However, with more efficient transportation and information resources available today, it seems logical that resupply would occur much more quickly. If so, the Air Force should be able to trim its wartime stocks of aircraft spares. This thesis investigated the effect of improving the logistics pipeline on the …

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A Cost Comparison Between Modes In The Shipment Of Mission Capable Parts Within The Continental United States, Jason L. Masciulli Mar 2001

A Cost Comparison Between Modes In The Shipment Of Mission Capable Parts Within The Continental United States, Jason L. Masciulli

Theses and Dissertations

A numerous amount of Mission Capable Parts (MICAPs) are shipped throughout the world by the Air Force. These parts are required in order to meet mission requirements. MICAPs are often shipped via an express, small parcel air carrier, like Federal Express (FedEx). However, there is a lower cost alternative: Less-Than-Truckload express carriers. In using actual Air Force MICAP shipping data, an 11 percent savings was shown if the lowest cost carrier, either FedEx or Roadway Express, an LTL express carrier, was used in shipping these MICAPs. Also, in using simulated shipping data, over 50 percent of all types of shipments, …

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Lifecycle Energy And Air Emission Differences Between Electric And Internal Combustion Vehicles, David L. Mccleese Mar 2001

Lifecycle Energy And Air Emission Differences Between Electric And Internal Combustion Vehicles, David L. Mccleese

Theses and Dissertations

The U.S. Federal Government has encouraged shifting from internal combustion engine vehicles (ICEVs) to electric vehicles (EVs) with three objectives, reducing foreign oil dependence, greenhouse gas emissions, and criteria pollutant emissions. This thesis uses Monte Carlo simulation to predict lifecycle emissions and energy consumption differences per kilometer driven from replacing ICEVs with three EV options: lead acid, nickel cadmium (Ni-Cd), and nickel metal hydride (NiMH). All three EV options reduce U.S. foreign oil dependence by shifting to domestic coal. The probabilities that lifecycle energy consumption per km driven improve are lead acid 76%, Ni-Cd 64%, and NiMH 90%. The probabilities …

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Establishing A Career Development Plan For The System Support Manager, Noelia Mendoza Mar 2001

Establishing A Career Development Plan For The System Support Manager, Noelia Mendoza

Theses and Dissertations

Career development plans are created to assist individuals in establishing their career objectives. The most commonly used career path model is the pyramid career model. It identifies the ideal job experiences, training, and education needed to reach career success. Although the model seems to provide everything needed to succeed, it fails to answer why the experiences identified are important. The answer to that question can be found in the competency model. This thesis looked at how the pyramid career model and competency model can be used to groom individuals. The variables that contribute to overall job performance and the competencies …

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Pilot Mental Workload Calibration, Jeremy B. Noel Mar 2001

Pilot Mental Workload Calibration, Jeremy B. Noel

Theses and Dissertations

Predicting high pilot mental workload is important to the U.S. Air Force because lives and aircraft can be lost when errors are made during periods of mental overload and task saturation. Current research efforts use psychophysiological measures such as electroencephalography, cardiac, ocular, and respiration measures in an attempt to identify and predict mental workload levels. The primary focus of this effort is the development of a calibration scheme that allows a small subset of salient psychophysiological features developed using actual flight data for one pilot on a given day to accurately classify pilot mental workload for a separate pilot on …

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Solving The Protein Structure Prediction Problem With Fast Messy Genetic Algorithms (Scaling The Fast Messy Genetic Algorithm To Medium-Sized Peptides By Detecting Secondary Structures), Steven R. Michaud Mar 2001

Solving The Protein Structure Prediction Problem With Fast Messy Genetic Algorithms (Scaling The Fast Messy Genetic Algorithm To Medium-Sized Peptides By Detecting Secondary Structures), Steven R. Michaud

Theses and Dissertations

The ability to accurately predict a polypeptide's molecular structure given its amino acid sequence is important to numerous scientific, medical, and engineering applications. Studies have been conducted in the application of Genetic Algorithms (GAs) to this problem with promising initial results. In this thesis report, we use the fast messy Genetic Algorithm (fmGA) to attempt to find the minimization of an empirical CHARMM energy model and generation of the associated conformation. Previous work has shown that the fmGA provided favorable results, at least when applied to the pentapeptide Met-Enkephalin. We extend these results to a larger Polyalinine peptide by utilizing …

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Predictability, Work-Family Conflict, And Intent To Stay: An Air Force Case Study, Patrick J. Obruba Mar 2001

Predictability, Work-Family Conflict, And Intent To Stay: An Air Force Case Study, Patrick J. Obruba

Theses and Dissertations

A survey was completed by 362 active duty Air Force members in December 2000 regarding their perceptions of schedule predictability, work-family conflict, job satisfaction, organizational commitment, and intent to stay with the Air Force. Theory suggests that a program designed to create schedule predictability, the Expeditionary Aerospace Force (EAF), would moderate the relationship between predictability and intent to stay. Using Structural Equation Modeling (SEM), plausible evidence was found to support the idea that schedule predictability plays a role in intentions to stay via work-family conflict, job satisfaction, and organizational commitment. Additional evidence supported the theory that the path relationships generated …

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Organizational Design Of Most Efficient Organization Air Force Civil Engineer Operations Flights, Jeffrey A. Payne Mar 2001

Organizational Design Of Most Efficient Organization Air Force Civil Engineer Operations Flights, Jeffrey A. Payne

Theses and Dissertations

This research explored how two MEO Operations Flights were structured and what type of operations management practices they were utilizing. The research involved performing site visits at the 17th Civil Engineer Squadron at Goodfellow AFB, and the 14th Civil Engineer Squadron at Columbus AFB. Data was collected through the use of the case study methodology in the form of interviews and organizational records. Data was organized to describe the two MEO's structures and management practices as well as compare the organizations to the Objective Operations Flight, the traditional Air Force Operations Flight. The data showed that both MEO's have taken …

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A Model To Predict Diffraction Attenuation Resulting From Signal Propagation Over Terrain In Low Earth Orbit Satellite Systems, Peter R. Pollock Mar 2001

A Model To Predict Diffraction Attenuation Resulting From Signal Propagation Over Terrain In Low Earth Orbit Satellite Systems, Peter R. Pollock

Theses and Dissertations

This study focused on multipath communication propagation impairments to the LEOSAT communications channel. Two terrain diffraction models, based on the geometric theory of diffraction (GTD), were developed and applied to the space-to-ground communications channel. These models were used to predict the impact of terrain on the performance of three LEOSAT communication systems with designs based on the Iridium, Globalstar and Orbcomm implementations. The study verified the feasibility of applying models based on the GTD rather than empirical or statistical models, to approximate the effect of propagating signals over terrain. Both models confirm that signal blockage and multipath propagation, due to …

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Estimating C-17 Operating And Support Costs: Development Of A System Dynamics Model, Christopher D. Purvis Mar 2001

Estimating C-17 Operating And Support Costs: Development Of A System Dynamics Model, Christopher D. Purvis

Theses and Dissertations

This research provides justification for experimenting with system dynamics (SD) for performing Operation and Support Cost estimates. For the C-17 Globemaster III cargo aircraft, these costs could exceed $64 billion dollars. Also, many of our weapon systems are beginning to reach the end of their effective life span, and discussions about the impact of aging, on aircraft, has become a hot topic in the literature. System Dynamics is a modeling methodology developed in 1958, but never used extensively for cost estimating. SD offers unique capabilities to the cost estimator, including the ability to model causal relationships. This capability offers the …

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Factors Affecting Exchange Relationships Among Subordinates And Supervisors: A Study Of Military Officers, Laurie K. Richter Mar 2001

Factors Affecting Exchange Relationships Among Subordinates And Supervisors: A Study Of Military Officers, Laurie K. Richter

Theses and Dissertations

This research examined the effect of organizational structure on the relationships between subordinates and their supervisors using measures of leader-member exchange (LMX), mentoring effectiveness, perceived organizational support (POS), perceived opportunities for promotion, job satisfaction, affective commitment, and intent to remain. The sample obtained included 147 subordinate Air Force traditional Civil Engineer officers, Explosive Ordnance Disposal (EOD) officers, Bioenvironmental Engineer officers, and 27 squadron commanders at 19 Air Force bases. The methods of multiple analysis of variance and structural equation modeling were used to evaluate five research questions and nineteen hypotheses. Overall, no differences were found between the types of subordinate …

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Fatigue Response Of Thin Stiffened Aluminum Cracked Panels Repaired With Bonded Composite Patches, Jason B. Avram Mar 2001

Fatigue Response Of Thin Stiffened Aluminum Cracked Panels Repaired With Bonded Composite Patches, Jason B. Avram

Theses and Dissertations

This research investigated the fatigue response of precracked and patched 2024-T3 Aluminum panels with stiffeners. Patches were single-sided, unidirectional three ply boron/epoxy. Stiffeners were 2024-T3 aluminum and were riveted and bonded on. Disbonds were introduced into the repair bondline by inserting teflon strips. Three disbond configurations were investigated rack tip disbond (CTD) located at the edge of the patch in the path of crack propagation, full-width disbond (FWD) covering the entire crack, and end disbond (ED) located at each end of the patch and covering the full width. Each repaired panel was subjected to tension/tension cyclic fatigue with a maximum …

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A Model For Palladium Catalyzed Destruction Of Chlorinated Ethenes In Contaminated Groundwater, Christopher M. Stoppel Mar 2001

A Model For Palladium Catalyzed Destruction Of Chlorinated Ethenes In Contaminated Groundwater, Christopher M. Stoppel

Theses and Dissertations

Groundwater contamination by chlorinated ethenes is a widespread environmental problem. Conventional remediation technologies have shortcomings that have prompted further research into the development of novel treatment technologies. A palladium/ alumina catalyst in the presence of dissolved molecular hydrogen (referred to hereafter as a PD/H2 system) has been demonstrated to rapidly destroy chlorinated ethene contaminated groundwater. First-order kinetics have been used to model chlorinated ethene destruction in a PD/H2 reactor. However, catalyst deactivation and regeneration are important processes that also need to be modeled in order to better understand their effect on treatment efficiency. This study presents a model …

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Decision Analysis Methodology To Evaluate Integrated Solid Waste Management Alternatives For A Remote Alaskan Air Station, Mark J. Shoviak Mar 2001

Decision Analysis Methodology To Evaluate Integrated Solid Waste Management Alternatives For A Remote Alaskan Air Station, Mark J. Shoviak

Theses and Dissertations

Eareckson Air Station (AS), a remote U.S. Air Force installation, faces the complex decision of selecting a new municipal solid waste (MSW) management strategy to replace its current non-compliant system. This research effort applies value-focused thinking and multiattribute preference theory to decision analysis techniques to produce a multiple-objective decision analysis model that captures all of the site's MSW goals, objectives, and concerns in order to facilitate the evaluation of MSW management strategies available. The model ranks 40 specific MSW management alternatives, which were developed in accordance with the decision-maker's assumptions and constraints, based on how well they meet Eareckson's overall …

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The Development Of A Finite Element Program To Model High Cycle Fatigue In Isotropic Plates, William C. Shipman Mar 2001

The Development Of A Finite Element Program To Model High Cycle Fatigue In Isotropic Plates, William C. Shipman

Theses and Dissertations

As part of a joint AFRL/DAGSI turbine blade research effort, a computer program has been developed that uses a von Karman large-deflection two-dimensional finite element approximation to determine stress levels and patterns in isotropic thin plates. The dynamic loading of various plates has been carried out in order to model a high cycle fatigue situation. The research considered the various effects of mode shapes, resident frequency, non-linear cyclic effect, endurance limits, and stress variations within a high cycle fatigue environment. Two main initiatives were taken. First, a transient analysis tool was developed that calculates stress and displacement patterns over a …

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