Engineering Commons^™

Effects Of Facility Configurations And Scheduling Techniques On Aircraft Throughput For Warner Robins Alc Paint/Depaint Facilities, David V. Mcelveen

Theses and Dissertations

The purpose of this research was to determine the effects of configuration options and dispatching rules on aircraft throughput for the WR- ALC paint/depaint facilities. A simulation model was constructed and used for this analysis as the primary means to conduct the research. The dispatching rules considered were first come first served, largest number in queue, shortest processing time, and a look ahead heuristic. Due to a reduction in the number of paint aircraft, no configuration option differing from the baseline significantly affected aircraft throughput. Dispatching rules were also found to produce no significant differences on aircraft throughput. Configuration options …

An Outline For A Manufacturing Planning And Control System For A Repair/ Overhaul/Rebuilding Environment, Peter H. Miyares

Theses and Dissertations

This study outlines a structure for a manufacturing planning and control (MPC) system for a repair/overhaul/rebuilding environment. Included an examination of the organizational components that must be incorporated into the system and the planning functions for which the system can be used. The study compares and contrasts the differences between an MPC system for a maintenance organization and a manufacturing organization and concludes that the MPC system for a maintenance organization must account for the greater degree of variability that occurs within the process. The proposed system is composed of an information system which collects data from throughout an organization …

Quantifying The Impact Of The Acquisition Professional Development Program Certification Requirements On The Air Force Institute Of Technology, Paul A. Nicholson

Theses and Dissertations

The purpose of this research is to determine the impact of implementing the Acquisition Professional Development Program on the Air Force Institute of Technology. APDP is part of a DOD-wide effort to decrease inefficiency in the procurement process. The program encompasses a tri-level certification process based on experience, training, and educational standards. APDP serves as a guideline for professional development of acquisition personnel from entry to senior level management. Many of the courses required for certification are offered through AFIT School of Systems and Logistics. Integrating the new educational requirements as a standard for career development is expected to produce …

A Sensitivity Analysis Of Circular Error Probable Approximation Techniques, Peter Puhek

Theses and Dissertations

Several algebraic CEP estimates models were examined in this study. Each assumes that the crossrange and downrange miss distances of the sample data follow a bivariate normal distribution. The analysis determined the sensitivities of these models to changes in the parameters of sample size, bias, correlation, and ellipticity. The accuracy of each model is expressed in terms of relative error, and the parameter regions in which a certain method dominated as the most accurate were noted. In general, it was found that bias was the most significant parameter in determining the best CEP method. A simple method, based on the …

Spartan: An Instructional High Resolution Land Combat Model, David K. Cox

Theses and Dissertations

This project developed an instructional high resolution land combat simulation model. The purpose of this model is to demonstrate common techniques of modeling used in the present generation of US Army land combat models. This model is stochastic and uses an event scheduling type of discrete event time algorithm. The model represents a maximum of two six-man infantry squads in direct fire combat. The individual soldiers move, search for targets, engage targets, and react to hostile encounters. The data values provided will the model are all. generic and hypothetical. The model is only intended as a demonstration tool and has …

Gettysburg: An Analysis Of The Training Value Of Commercial Models, Jude C. Fernan

Theses and Dissertations

This study investigated the possibilities of using commercial combat models/war games dealing with the battle of Gettysburg as aids for the training of soldiers and leaders in the military. With the downsizing of the military and the high cost of training, there exists a need to reduce training costs while not affecting the quality of training. The military employs various military models to assist in training but has yet to fully tap the wealth of commercial combat models. One reason may be the lack of an investigative analysis into the soundness and applicability of commercial combat models to military training. …

A Decision-Theoretic Approach To Recommending Action In The Air-To- Ground Aircraft Of The Future, Garrison H. Flemings

Theses and Dissertations

Designers of air-to-ground fighters of the future should consider including decision support systems to relieve pilots of some of the present workload. Those decision support systems should use utility theory. This work reviews two techniques of utility theory (decision trees and influence diagrams) and a new technique due to Morlan (probability ratio nets). The work includes a proposed structure for action recommendation systems in air-to-ground fighters of the future. The work describes an implementation of probability ratio nets. The work demonstrates the value of decision theory to air-to-ground fighters of the future by way of solving an example problem and …

Saber: Airland Combat Training Model Credibility Assessment And Methodology, David L. Scagliola

Theses and Dissertations

Saber is a theater-level, airland combat training model, designed by a number of computer science and engineering students and faculty at the Air Force Institute of Technology (AFIT). Saber is intended to replace the Agile model, which is currently used at the Air Force Wargaming Center, Maxwell AFB, Alabama for Theater Warfare Exercise (TWX) training purposes. This thesis focuses on the progress made towards generating the Saber training model, its ability to meet the objectives specified by the Wargaming Center, and its ability to represent actual combat. Specifically, this thesis is directed towards characterizing, establishing a credibility assessment, and developing …

A Response Surface Methodology Study Of Ferroelectric Memory Devices, Kevin C. Smith

Theses and Dissertations

Fatigue in ferroelectric memory devices was studied. The application of fatigue pulses to a ferroelectric sample was controlled by the RT-66 Ferroelectric Tester, a variation of the Sawyer-Tower circuit. The RT-66 also controlled data collection following the fatiguing process. Seven variables were evaluated for their potential- affect on fatigue. A sequence of fatigue tests, which varied the settings of these variables, was developed using Response Surface Methodology (RSM) experimental designs. Least-squares regression models were developed once a particular RSM set of design experiments was completed. These models were evaluated using RSM tools, and the analysis of these models allowed the …

Improved I/O Pad Positions Assignment Algorithm For Sea-Of-Gates Placement, Shyang-Kuen Her

Dissertations and Theses

A new heuristic method to improve the I/O pad assignment for the sea-of-gates placement algorithm "PROUD" is proposed. In PROUD, the preplaced I/O pads are used as the boundary conditions in solving sparse linear equations to obtain the optimal module placement. Due to the total wire length determined by the module positions is the strong function of the preplaced I/O pad positions, the optimization of the I/O pad circular order and their assignment to the physical locations on the chip are attempted in the thesis. The proposed I/O pad assignment program is used as a predecessor of PROUD. The results …

Hypoid Gear Optimization, Selvaraj Ramachandran

Dissertations and Theses

A hypoid gear optimization procedure using the method of feasible directions has been developed. The objective is to reduce the gear set weight with bending strength, contact strength and facewidth-diametral pitch ratio as constraints. The objective function weight, is calculated from the geometric approximation of the volume of the gear and pinion. The design variables selected are number of gear teeth, diametral pitch, and facewidth. The input parameters for starting the initial design phase are power to be transmitted, speed, gear ratio, type of application, mounting condition, type of loading, and the material to be used. In the initial design …

An Intelligent Database For Psubot, An Autonomous Wheelchair, Dieudonne Mayi

Dissertations and Theses

In the design of autonomous mobile robots, databases have been used mainly to store information on the environment in which the device is to operate. For most of the models and ready systems, the database when used, is not a stand alone component in the system, rather it is only intended to keep static information on the disposition and properties of objects on the map.

In this thesis is implemented an intelligent database. It combines static facts to build more information. An intelligent database such as this one will be a plus for an intended autonomous machine such as the …

An Application Of The Finite Element Method In Forging, Hazim Atef El Mounayri

Archived Theses and Dissertations

No abstract provided.

An Examination Of Wing Rock For The F-15, Michael T. Davison

Theses and Dissertations

Wing rock in the F-15 was examined both analytically and experimentally. Using a previously developed model for the F-15, bifurcation analysis and continuation techniques were used to map out the periodic wing rock solutions and the equilibrium solutions leading up to wing rock. this was done for four maneuvers; a 1 g stall, rudder sweeps, constant bank turns and a symmetric pullup. To supplement this research, time history simulations were used to examine. the time history of wing rock. A study of stability derivatives was also done, to determine the critical parameters in wing rock. Bifurcation was also used to …

A Computer Based Educational Aid For The Instruction Of Combat Modeling, Richard S. Moore

Theses and Dissertations

The Air Force Institute of Technology is one of few institutions that teaches combat modeling. Combat models are typically dynamic computer simulations of specialized dynamic processes. Great difficulty exists in portraying these dynamic and recurrent processes with conventional static diagrams. This thesis produced a computer-based instructional aid which presents animated examples of processes common to combat models, demonstrates a simple few-on-few aerial combat model, and encourages student exploration and interaction with these presentations. This aid provides dynamic examples of random number generation, detection processes, target selection, and target destruction. A complete combat model demonstrating a few-on-few air duel is animated …

Improving The Throughput Of Plasticating Extruders : Manufacture Of Non-Circular Pellets, Measurement Of Their Interparticulate Friction Coefficient, And Implications For Screw Design, Chia-Ying Liu

Dissertations

This dissertation addresses the hypothesis that the interparticulate friction coefficient of a bed of polymeric particulates is a function of the cross-section of the pellets. Most pellets have a circular cross-section especially those that are strand cut. But when such pellets constitute a particulate bed there are few restrictions to adjacent pellets turning with respect to each other, or of the beds rupturing under shear load. This rupture can occur in plasticating extrusion, and it results in a poorly mixed melt with an inhomogeneous temperature distribution. The temperature fluctuations cause viscosity fluctuations which in turn cause pressure fluctuations. The pressure …

Series Compensation Investigation On The Hydro-Quebec And Nypa 765 Kv Transmission System : Modeling And Stability Analysis, Hans J. Candia

Theses

This thesis presents a mathematical approach for raising the power steady state stability limit by adding series capacitive compensation to a transmission line. The effect of series capacitive compensation and degree of compensation were investigated in detail. The power system studied includes an automatically controlled power system, IEEE Type I.

The results of the actual and theoretical steady state stability limits for a given series capacitance location and degree of compensation were obtained by applying the frequency domain technique. The natural frequencies of each compensated power network were examined.

The best location for series capacitive compensation is proposed which is …

Mathematic Models On Leaching Behavior Of Chemical Solidification And Stabilization Process For Heavy Metal Sludges, Sz-Hung Chen

Theses

Chemical Solidification and Stabilization of toxic metal-containing sludges is one of the most important problems for environmental protection. Although Chemical Solidification and Stabilization of hazardous wastes prior to disposal is increasing in importance, very little work has been done concerning the leaching mechanisms and kinetic models.

In this study, we apply Freundlich & Langmuir isotherms on Chemical Solidification and Stabilization process, and the theoretical results match with experimental data very well. In the same time, we develop a simple methematical kinetic model which relates leaching concentration of heavy metal to curing time. In this study kinetic model, what you need …

A Finite Element Thermal And Diffusion Analysis At Bearing Metal Interface In Extrusion Processes, Biju Dennis

Theses

A mathematical model is developed to study the effect of extrusion speed and the bearing length on the surface temperature along the die billet interface. The surface temperature distribution resulting from the plastic work done on the die billet interface is studied. Finite element analysis is done on the model incorporating the mass transport effect occurring during the extrusion process and the interdependence of various parameters are presented. Die wearing problem is analyzed considering the effect of diffusion. Thermal analogy of the diffusion problem is utilized in the development of the mathematical model for diffusion problem and finite element analysis …

Computer Numerical Controlled (Cnc) Machining Of Screws And Dies For Plasticating Extruders : Determination Of The Criteria For Implementing Cnc Machining, Nilesh H. Desai

Theses

The work of this thesis is dedicated to the manufacturing industry making production equipment to manufacture plastic products. The main theme of the thesis is to determine the criteria for implementing Computer Numerical Control machining to make parts with complex geometries for production equipment.

A small manufacturing company with job shop type of production was chosen as the subject and study of extruder manufacturing process was performed. The various available alternatives of CNC manufacturing units available in the market were chosen and their feasibility examined.

At present a large variety of CNC machine tools are available in the market, offered …

Ion Exchanged Glass Waveguides With Efficient Coupling To Fibers And Lasers, Shiqing Hu

Theses

To be of practical use in optical communications networks, optical components must have both low on-chip losses and efficient coupling to fibers, semiconductor lasers and detectors. In this thesis work two types of channel waveguides were designed and fabricated on BK7 glass substrate using a low-cost ion-exchange process. The first type of waveguide was formed in a simple sequence of ion-exchange and post-exchange annealing. These single mode waveguides had large mode size and were efficiently coupled to single mode fibers. The lowest loss achieved in fiber-guide direct coupling was 1.25 dB. The second type of waveguide was formed in a …

Computer Aided Shape Optimization Using Finite Element Analysis, Charanpreet Singh Bagga

Theses

Various theories behind Computer Aided Shape Optimization are studied. A special attention is paid to the shape representation, mesh generation and refinement during the shape optimization process. Shape optimization process for a wall bracket is performed using the Computer Aided Engineering package of I-DEAS. Finite element analysis of the wall bracket is done and the stress distribution over the bracket is studied. The bracket is trimmed in the selected low stress regions using shape optimization capability of I-DEAS and an optimized shape of the wall bracket is obtained. The end product is evaluated using Supertab module of I-DEAS as well …

Conditional Artificial Dielectric : Optically Controlled Microwave Modulator, J. Manuel Jimenez

Theses

A conditional artificial dielectric with embeddings of either CdS, GaAs or Si in PMMA form the dielectric material of a microstrip in a homodyne microwave detection system. The system consists of a Michelson or Mach-Zehnder interferometers with the microstrip placed in one arm. The index of refraction of the microstrip substrate is modulated by chopped incident light causing amplitude and phase variations in the incoming RF signal. Those variations are detected by mixing the light modulated microwave carrier(information channel) with the unmodulated carrier (reference channel) in the interferometer. The output is sensed by the square law detector and a lock-in …

Efficient Hypercube Communications, Shreyas R. Bhatt

Theses

Hypercube algorithms may be developed for a variety of communication-intensive tasks such as sending a message from one node to another, broadcasting a message from one node to all others, broadcasting a message from each node to all others, all-to-all personalized communication, one-to-all personalized communication, and exchanging messages between nodes via fixed permutations. All these communication patterns are special cases of many-to-many personalized communication. The problem of many-to-many personalized communication is investigated here.

Two routing algorithms for many-to-many personalized communication are presented here. The algorithms proposed yield very high performance with respect to the number of time steps and packet …

Biodegradation Of Phenol And Benzoic Acid In Batch And Sequencing Batch Reactors, Stephane Reynaud

Theses

A pure culture of Pseudomonas aeruginosa ( ATCC 10145 ) was used for the biodegradation of phenol and benzoic acid. Two sets of small scale (shaker flask) experiments were originally performed: in the first set, phenol was the only carbon source present while in the second, benzoic acid was the sole carbon source. These experiments revealed the kinetics of benzoic acid degradation (they were found to be described by a Monod, non-inhibitory model), as well as of phenol biodegradation (they were found to be described by Andrews'inhibitory model) by Pseudomonas aeruginosa.

The kinetic expressions from the small scale experiments …

Developing Image Processing Tools In X Window System, Xin Zhang

Dissertations and Theses

The X Window System is an industry-standard software system which facilitates programmers to develop portable graphical user interfaces. This thesis describes an image processing tool developed under the X Window System. A multiwindow image display software with image editing and improvement functions is developed. The software has four modules: environment generation, image creation, image editing and image improvement.

The environment generation module creates working windows, scrollbars, dialogbox and pulldown menu buttons, and tracks mouse cursor positions. The working windows are three adjacent windows allowing display of three different images simultaneously. The dialogbox provides an interface between the user and the …

Electromagnetic Focusing Properties Of Chirped Metallic Gratings, Jeffrey C. Schmidt

Retrospective Theses and Dissertations

The focusing properties of chirped diffraction gratings have long been studied and often used in applications at optical frequencies. Chirped metallic gratings of this type have also been studied theoretically at microwave frequencies, but no attempt has been made to experimentally examine or utilize the focusing properties of these structures at microwave frequencies. This thesis presents an experimental analysis of the focusing properties of chirped metallic gratings. These gratings are designed to focus electromagnetic energy at a predetermined position by varying strip width and spacing as a function of position. The diffraction gratings are characterized, and experimentally measured results are …

Microchannel Fluid Flow In A Silicon Chip, Ronald R. Ulseth

Retrospective Theses and Dissertations

The objective of this study was to analyze theoretically and experimentally the fluid characteristics of forced flow in microchannels. An apparatus was designed and constructed to allow microflow through a 450 μm wide by 17. 5 μm deep microchannel in a silicon chip. The flow through the chip was laminar with Reynolds numbers not exceeding 100. Tuckerman and Pease (1981) theorized that microscopic heat exchangers etched in the back of silicon chips could provide for efficient heat removal from the chips at rates much higher than the conventional methods could attain. The best technologies available provided for heat removal rates …

Emissions Of Hexavalent Chromium From Hard Chromium Plating Operations, Mitchell Scott Hall

Retrospective Theses and Dissertations

This research addresses emissions of hexavalent chromium mist from hard chromium electroplating operations. Most of these emissions are typically captured by a ventilation stack and directed to a pollution control device; those which escape capture are called fugitive emissions. Releases of toxic materials such as hexavalent chromium must be reported annually to the Environmental Protection Agency (EPA) under provisions of the Superfund Amendments and Reauthorization Act (SARA) Title III of 1986 via the Toxic Release Inventory (TRI), Form R. The objectives were: (1) to provide estimates of fugitive hexavalent chromium emissions for the completion of Form R; and (2) to …

Express Transit Service For The University Of Central Florida, Arturo J. Perez

Retrospective Theses and Dissertations

As one of the fastest growing universities in the State of Florida, the University of Central Florida (UCF) is faced with the hardships placed on higher learning institutions across the nation. The increase of students paralleled by the increase of motor vehicles on the university campus, and the shortage of funding needed to construct the necessary parking facilities to support this growth, has left the University with a big dilemma, whether to try to overcome the parking space deficit by building the needed spaces to accommodate the demand, or provide a mass transit system that would reduce the number of …