Engineering Commons^™

Case Studies In The Analysis Of The Dod Migration System Selection Process, Paul E. Boley Ii

Theses and Dissertations

One of the focuses of Corporate Information Management (CIM) initiative in the Department of Defense is the elimination of duplicate automated information systems. This thesis is a case study examination of the selection process in the logistics, transportation, and health functional areas. The case studies were performed through a one-time review of documents relating to system selections in each functional area. A review of strategic information systems planning and systems implementation literature is used to examine the results in the three areas. The thesis concludes with three suggestions for improving the selection process with an emphasis on systems implementation.

Economic Analysis For An F-22 Organic Vs. Contractor Aircraft Battle Damage Repair Ownership Decision, John A. Kitchens

Theses and Dissertations

The purpose of this study was to evaluate whether Contractor Logistics Support (CLS) is a viable alternative to Combat Logistics Support Squadrons (CLSSs) for providing F-22 Aircraft Battle Damage Repair (ABDR). Legalities, practicalities, and cost-effectiveness were key ownership concerns. United States Code, Office of Management and Budget, Department of Defense (DoD), and United States Air Force (USAF) requirements were reviewed to address legal and policy issues and whether F-22 ABDR is military essential. The Army's Logistics Civil Augmentation Program (LOCCAP) award fee history was used to assess the potential performance of F-22 ABDR CLS personnel. F-117 ABDR team requirements and …

How The Presence Of A Risk Ladder, Time Interval Comparison, And Smoking Comparison Affect Risk Perception, Steve A. Dinzart

Theses and Dissertations

The objective of this study is to increase the knowledge available on the relative effectiveness of risk ladders as a presentation format for explaining risk magnitudes to the public. An experiment was conducted to test the hypotheses that an individual's risk perception varies with the presence of a risk ladder, time interval comparison, and smoking comparison. Subjects were AFIT Professional Continuing Education students, asked to assume a particular level of a health hazard in their homes, to read a brochure explaining the hazard, and then to complete a questionnaire. Results demonstrated that subjects exposed to a graphical risk ladder perceived …

The Effects Of Extraneous Presentation Graphics On Decision Making, Thomas S. Tingley

Theses and Dissertations

Almost every professional presentation includes some form of graphics. Many previous researchers have analyzed the relative effectiveness of graphical decision aids, such as pie charts or bar graphs. Very little research, however, has been conducted to determine the effects of extraneous graphics, such as pictures and logos, on decision making. This study employed an experiment to determine whether extraneous graphics hinder or enhance a decision maker's ability to obtain the pertinent information from a professional presentation. Other factors such as gender and graphics training were also analyzed for any influence on the results obtained. The results of the study indicated …

Aerial Port Location Study, Levenchi L. Dingle

Theses and Dissertations

This study performed an investigation on determining the appropriate number and locations of continental United States aerial ports. To accomplish this a linear programming formulation was adapted with the optimizing function based on trading off the cost of shipping cargo against port operating costs. Cargo would travel from CONUS origin, through aerial port of embarkation (APOE), to aerial port of debarkation (APOD) at minimum cost to the DoD. The need for the study was precipitated by continued reductions in the military budget, consolidation of defense depots, and the reduction in the number of personnel stationed overseas. Cargo movement data was …

Predicting Mishap Rates At Closing Usaf Maintenance Depots, Douglas E. Mcclain

Theses and Dissertations

It is clear that the Department of Defense and the USAF, in an effort to cut costs, will continue to reduce infrastructure through base closures. This has particular implications to the civilian employee who will likely lose his or her job. The purpose of this study was to review the most recent literature relating to safety and industrial facility closures and develop a theoretical model for predicting accident or mishap rates. From the literature reviewed, a theoretical model is proposed containing five candidate variables intended to measure; perceived adequacy of employee safety training, perceived safety culture, perceived safety climate, self-reported …

Comparison Of Effects Of Change From 8 To 12 Hour Shifts On Air Force Aircraft Maintenance Workers, Daniel W. Overland

Theses and Dissertations

This study examined the effects of converting from an 8 hour shift system to a 12 hour system on aircraft maintenance personnel. The squadron had converted its 24 hour operations from an 8 hour shift schedule to a 12 hour shift schedule in stages, changing one group first and then another. A smaller third group of workers remained on 8 hour shifts. Individual differences in job related outcomes and situational constraints were measured for all three groups. Results showed that changing from 8 to 12 hour shifts affected worker well-being and morale, as indicated by an increase in hospital visits …

Reducing Cannon Plug Connector Pin Selection Time And Errors Through Enhanced Data Presentation Methods, Robert R. Webb

Theses and Dissertations

The purpose of this research is to investigate the effects of data presentation methods on technician performance when the procedures are presented on a monocular, head mounted display (HMD) in a static maintenance environment. This research used two different methods to present the maintenance task data to the technicians. The first method showed the task as it is typically described in standard technical manuals. It described the task to perform and provided a basic picture of the cannon plug to be tested (unenhanced). The second method provided the same information as the first, but it also modified the information by …

Cost Per Flying Hour Analysis Of The C-141, Christopher J. Omlor

Theses and Dissertations

This paper sought to examine if DoD's current transfer pricing method places AMC in a price competitive position with the government commercial rates and promotes managers to make the best decisions. Attention was paid to the stated customer concerns that current transfer pricing methods incorporate overhead and sunk costs that are not attributable to routine movement of peacetime cargo and could make AMC non price competitive with commercial vendors. The findings are that AMC currently uses full cost transfer pricing, as required by DoD policy, that includes significant overhead and sunk costs associated with its wartime responsibilities. The full cost …

Modeling Improvements For Water Supply Forecasting In The Columbia River Basin, Daniel Albert Buller

Dissertations and Theses

The purposes of this study were twofold. The first was to explore possible improvements that could be made over existing methods by applying alternative modeling approaches, including the one developed by Garen to forecast runoff volumes in the Columbia River at The Dalles, Oregon. The second was to use the Southern Oscillation as one of the variables to forecast spring and summer runoff and to evaluate whether this variable adds significant information early in the season before any snow has accumulated. The Columbia River basin's mountainous topography and northern latitude are ideally suited for water supply forecasting because much of …

Flow Due To A Moving Pressure Distribution Over Free-Surface With Finite-Depth Bottom, Noriaki Okita

Masters Theses

Two-dimensional, steady-state and time-dependent analysis of wave making phenomenon due to a moving pressure distribution in sub-critical Froude number was performed. The domain is consisted of undisturbed free-surface at y=0, flat bottom at y=-h, and it is unbounded in horizontal direction. The pressure distribution was treated as an ideal model of an air-cushioned-vehicle (ACV). Ideal flow theory and linearized boundary conditions were used. Numerical integration algorithm was developed to evaluate the analytical solution. The surface elevation, bottom pressure profiles, and wave resistance were analyzed as functions of speed and depth.

The steady-state wave resistance calculated from the surface elevation profile …

Performance Of An Air Conditioning System Using R-134a As A Refrigerant, Abdelrahman I Elsherbini

Archived Theses and Dissertations

No abstract provided.

Fabrication, Structure, Properties And Workability Of Al 2024/Sic Particulate Composites, Renee Naim Aziz

Archived Theses and Dissertations

No abstract provided.

Fabrication, Structure, Properties And Workability Of Al 2024/Sic Particulate Composites, Renee Naim Aziz

Archived Theses and Dissertations

[abstract not provided]

Experimental Investigation Of Nonlinear Dynamics In Single Mode Semiconductor Laser Diodes With Phase Conjugate Feedback, Gordon T. Hengst

Theses and Dissertations

The semiconductor laser diode offers a unique system to investigate nonlinear dynamics when optical feedback is applied. Although there is extensive research of laser diodes with optical feedback from normal dielectric mirrors, very little has been done experimentally to analyze the effects of degenerate phase conjugate feedback from a BaTiO₃ crystal. This research experimentally investigated the dynamics of a single-mode laser diode with weak phase conjugate feedback using both the self-pumped and double phase conjugate geometries. The experimental results validated a mathematical model which numerically evaluates the Lang-Kobayahsi coupled differential equations. The model simulated the nonlinear behavior of a …

Application Of Active Noise Control To Reduce Cabin Noise In Single Engine General Aviation Aircraft, Jeroen Hendrik Dolmans

Master's Theses - Daytona Beach

The application of active noise control to reduce cabin noise in single engine, general aviation aircraft is investigated through the use of the 'filtered x' least mean square algorithm and a simple acoustic feedforward method to generate a reference signal is tested. The system is designed to utilize one reference signal and up to two feedback signals and two audio speakers. The feedforward system consists of a microphone placed in close proximity to the front windshield and isolated from the cabin noise. Cabin noise and reference signals are recorded during flight in a Cessna 172 Skyhawk, a Piper Cherokee 140 …

High-Order Finite-Difference Schemes And Their Application To Computational Acoustics, Joe Leo Manthey

Mathematics & Statistics Theses & Dissertations

The primary focus of this study is upon the numerical stability of high-order finite-difference schemes and their application to duct acoustics. Since acoustic waves are known to be non-dissipative and non-dispersive, high-order schemes are favored for their low dissipation and low dispersion relative to the low-order schemes. The primary obstacle to the the development of explicit high-order finite-difference schemes is the construction of boundary closures which simultaneously maintain the formal order of accuracy and the numerical stability of the overall scheme. In this thesis a hybrid seven-point, fourth-order stencil for computing spatial derivatives is presented and the time stability is …

Investigation Of Drag Reduction On A Two-Dimensional Circular Cylinder By Ejecting Jet From The Rear Stagnation Region, Satoshi Atsuchi

Mechanical & Aerospace Engineering Theses & Dissertations

Extensive work in the field of drag reduction has been done in the past. However, this field of study is highly desirable today because of various high-speed research programs. The present study attempts to investigate the feasibility of drag reduction on a cylinder by flow injection from the rear stagnation region. A two-dimensional circular cylinder at Reynolds number l x10⁵with a jet ejected from its tail is selected as a physical model. To tackle this problem, a numerical simulation as well as an experimental approach were used. Despite the recent development of computational fluid dynamics (CFD), computing a …

A Comparison Between Simulated And Measured Free-Flight Vortex Encounter Behavior In The Nasa Langley Full-Scale Wind Tunnel, Robert A. Pfouts

Mechanical & Aerospace Engineering Theses & Dissertations

An examination of the use of static measurements in simulating dynamic aircraft­ wake encounters is presented. By comparing dynamic aircraft-wake vortex encounter measurements obtained in free-flight wind tunnel tests to data obtained from computer­ simulated encounters based on static wind tunnel data, a determination is made concerning the validity of static vortex models in a dynamic flight environment. The development and testing of specialized elements of a flight simulation code are presented and dynamic free-flight measurements and predicted results are compared.

This study shows that static modeling provides reasonable estimates for lateral encounter trajectories when the following aircraft model is …

The Detoxification Of Petroleum Contaminated Coastal Plain Sandy Soil Using An Amended Vermicomposting Approach, John Charles Kraemer

Health Services Research Dissertations

This study explores the feasibility of utilizing an amended vermicomposting treatment approach for detoxifying petroleum hydrocarbon contaminated sandy soil. The bench-scale testing of gasoline and diesel contaminated soil using three test soil vessels and one control soil vessel was performed in a laboratory setting for a six week time period. The control soil received no treatment other than distilled water to maintain soil moisture. Treatment 1 consisted of direct application of liquid municipal biologic sludge on a weekly basis. Treatment 2 consisted of the addition of 30 Eisenia foetida earthworms and distilled water. Treatment 3 consisted of direct application of …

Electromyography (Emg) Signal Classification By Artificial Neural Networks, Behnam Dashtipour

Electrical & Computer Engineering Theses & Dissertations

EMG signal processing is one of the active fields of biomedical signal processing. One unanswered question is how to determine whether a muscle is fatigued by analyzing the EMG signal. Fatigue detection could be useful in several different practical situations. There are several studies which show there are differences between EMG signal features before fatigue and after fatigue. Generally studies are based on an analytical analysis of the EMG signal instead of a quantitative analysis. In all previous studies in EMG signal processing for fatigue/nonfatigue detection, the result is that there exist some differences between the EMG signal before muscle …

Computer-Aided Design Of Coupler-Driven Watt I And Tolerance Synthesis For Four-Bar Linkages, Haitao Li

Mechanical & Aerospace Engineering Theses & Dissertations

Theory to rectify circuit defects in rocker-crank and double-rocker at the synthesis level is described based on the angular joint displacements. It complements the crank-rocker and double-crank circuit rectification to complete the circuit rectification of four-bar linkages. The procedure utilizes the algebraic method where special points followed by a line construction procedure are employed to validate the range of the critical angle that can identify the circuit defects as a function of the design positions prior to the completion of the linkage.

A complete procedure of the rectified synthesis of the coupler-driven Watt I six-bar linkage to pass through the …

Reverse Engineering Of Aircraft Wing Data Using A Partial Differential Equation Surface Model, Jacalyn M. Huband

Mathematics & Statistics Theses & Dissertations

Reverse engineering is a multi-step process used in industry to determine a production representation of an existing physical object. This representation is in the form of mathematical equations that are compatible with computer-aided design and computer-aided manufacturing (CAD/CAM) equipment. The four basic steps to the reverse engineering process are data acquisition, data separation, surface or curve fitting, and CAD/CAM production. The surface fitting step determines the design representation of the object, and thus is critical to the success or failure of the reverse engineering process. Although surface fitting methods described in the literature are used to model a variety of …

Research Related To Multi Degree Of Freedom Magnetic Suspensions, Yan Yang

Mechanical & Aerospace Engineering Theses & Dissertations

This thesis covers the activities associated with 1) recommissioning of the 6-inch Magnetic Suspension and Balance System (MSBS) and 2) enhancing the Annular Suspension and Pointing System (ASPS). These activities continue the program of research in the multi degree of freedom magnetic suspension program at Old Dominion University. The 6-inch MSBS is a large gap magnetic suspension system used as a model support and balance system in wind tunnels. The first stage of recommissioning of the 6- inch MSBS for the 6-inch subsonic wind tunnel is performed. Experimental data and computational results for the magnetic field distribution of the MSBS …

Gfrp External Strengthening Of Structural Concrete, Tarek Mohamed Nabil Fathy Rizk

Archived Theses and Dissertations

No abstract provided.

Fabrication And Mechanical Properties Of Aluminium Composite Duplex Alloys By Semisolid Forming, Merhane Mohamed Kamel

Archived Theses and Dissertations

No abstract provided.

A Piezoresistive Metal Thin Film Tilt Sensor, Todd Allan Lindley

Electrical & Computer Engineering Theses & Dissertations

Thin film strain gauges have many applications as transducers for monitoring pressure, vibration, and acceleration. In this thesis, a simple system, consisting of a Nichrome thin film strain gauge deposited on a glass substrate, is investigated in detail. Finite element analysis is used to model the expected sensor behavior. The substrate is shaped to exhibit a constant strain distribution, and is set up in a cantilever beam configuration. R. F. sputtering is used to deposit the Nichrome film, and the resistor pattern is transferred via photolithography. The gravitational force on a mass attached to the free end of the sensor …

Specification And Verification Of Generic Cell Rate Algorithms In Pvs, Huseyin Ozgungor

Electrical & Computer Engineering Theses & Dissertations

Formal verification methods have been considered as a powerful complementary approach to define standards and to prove correctness of the systems. In this work, formal specification of Generic Cell Rate Algorithms are defined and proved. The specification process enables standardization for constructing Generic Cell Rate Algorithms. Standardization is an important process in the Asynchronous Transfer Mode (ATM) networks. By employing formal methods, the necessary standards could be constructed to allow different algorithms to be employed which still meet system requirements. Those system requirements are quantified in the Quality of Service (QOS).

Congestion management is a vital concept for networks in …

Interactive Approach For Geometry Definition With Automatically Differentiated Sensitivities For Practical Airplane Design, Yvette Cordero

Mechanical & Aerospace Engineering Theses & Dissertations

First, a newly developed interactive surface generation tool is described for the conceptual design phase and aerodynamic shape optimization of aircraft. The new design tool is called Interactive Rapid Airplane Parametric Input Design (IRAPID) for fuselage and wing body configurations, and Blended Wing Body (BWB) generator for flying wing configurations. The development of the software is based on the RAPID methodology, which incorporates a partial differential equation approach to surface design. By incorporating physical airplane design parameters into the boundaty conditions of the partial differential equation, the solution surface of a wing configuration is generated. The construction of fuselage components …

Dyna3d Simulations Of Low-Speed Impact Response Of Laminated Composite Panels, Kenneth William Barlow

Mechanical & Aerospace Engineering Theses & Dissertations

Low-speed impact response of laminated composite panels is simulated without material damage using the DYNA3D finite element analysis code. The DYNA3D code is a nonlinear transient dynamics simulation tool with a contact algorithm for impact. By gaining a more comprehensive understanding of this dynamic impact event, this work is meant to contribute to improving designs for damage tolerance and residual strength by providing modeling and analysis guidelines for the analyst.

Structural modeling of the laminate and the impact event are found to be important factors for the analyst to consider. Since DYNA3D uses an explicit formulation, problem size is constrained …