Engineering Commons^™

Cathodoluminescence Of Gaas, Tyler Smith

Electrical & Computer Engineering Theses & Dissertations

Cathodoluminescence of band-gap radiation across the bulk of a proposed semiconductor switch has been studied. Such a device relies on the efficient use of cathodoluminescence to modulate the conductivity of the switch. Diagnostics were configured to measure the intensity of band-gap radiation across the bulk of several switch samples. The measured results were compared to calculations based on a four energy level band-gap model which included two deep levels EL2 and HL10.

A Comparative Analysis Of The Efficacy Of Zero-Order, First-Order And Monod Kinetic Models In Representing Raw Aerobic Biodegradation Data, Andrew I. Bakun

Theses

A total of 148 raw aerobic biodegradation data sets from batch and continuous stirred-tank reactors were extracted from the open literature and previous NJIT MS theses. Kinetic analysis of each of these data sets was performed with respect to the following commonly used empirical models: (1) zero-order, (2) first-order, and (3) Monod. Two constant-biomass versions of each model were evaluated; one in which So (i.e., the boundary condition for substrate concentration at time equal to zero) was assumed to be equal to the measured value of the initial substrate concentration and the other in which So was treated as a …

Simulation Study Of Signal Coupling For Monolithic Gaas 8-12 Micron Direct Injection Mqw Image Sensor, Lei Zhang

Theses

The simulation of signal coupling for a single pixel of a monolithic 8-12 micron GaAs/A1GaAs direct injection MQW infrared image sensor with 100% fill factor has been performed by using PISCES-IIB and PSPICE simulators. A vertical structure with the readout circuit built on the back of MQW was adopted for simulations. Both the static and transient characteristics were analyzed by simulation. The simulation was used to verify the doping profiles and device parameters for the n-GaAs MESFETs used in the read-out circuit.

The simulation result is as follow:

(1) A 900A thick p-GaAs (p=10¹⁶/cm3) substrate for GaAs MESFETs …

Optimal Sustained-Yield Groundwater Pumping Strategy For The East Shore Area, Utah, Shu Takahashi, Richard C. Peralta

Civil and Environmental Engineering Faculty Publications

Optimal sustained-yield pumping strategies were developed for the irrigated and industrialized eastern shore of the Great Salt Lake. The combined optimization and simulation model contains steady-state, finite difference, quasi-three-dimensional, groundwater flow equations embedded as constraints. The model computes the optimal spatial distribution of sustainable annual groundwater pumping rates for alternative scenarios. The addressed aquifer is a multilayer and confined/unconfined (linear/nonlinear) system. The research can help manage water in the study area, where the demand for water of sufficient quality and quantity is increasing due to urbanization.

Tractor Museum Committee Establishment 1991, Tractor Museum

Lester F. Larsen Tractor Museum: Planning and Development Documents

No abstract provided.

Cognitive Learning Styles And Their Relation To Air Traffic Control Screening And Training, Vincent P. Galotti

Master's Theses - Daytona Beach

The purpose of this study was to show a relationship between the type of cognitive learning style that an individual possesses and their subsequent success at simulated air traffic control practical exercises. Kolb's Learning Style Inventory was utilized to determine dominant learning styles of 30 college students enrolled in a laboratory-based air traffic control course. The instrument was administered during the first day of classes in the Fall of 1990. Students were placed in one of four groups for statistical purposes according to learning style. The scores of simulated micro-computer based air traffic control practical exercises given at semester's end …

Simultaneous Extraction And Sorption Under Supercritical Conditions, Ş. Uğur Akman

USF Tampa Graduate Theses and Dissertations

Supercritical Exsorption (SCEXS), simultaneous supercritical extraction and sorption (adsorption and/or desorption), is a novel process which may have potential for applications in chemical, biochemical and environmental engineering. The system of interest consists of a fixed-bed packed with an adsorbent (e.g., activated carbon or catalyst) through which a so~vent stream (e.g., supercritical carbon dioxide) and a feed stream (e.g., an aqueous stream with low concentration of solute such as phenol) flow countercurrently.

In this work, the theoretical foundations of SCEXS have been established through distributed-parameter modeling which enables phenomenal description of several probable three-phase mass transfer dynamics taking place in the …

Investigation Of Real-Time Optical Scanning Holography, Bradley D. Duncan

Electro-Optics and Photonics Faculty Publications

Real-time holographic recording using an optical heterodyne scanning technique was proposed by Poon in 1985. The first part of this dissertation provides a detailed theoretical treatment of the technique, based on a Gaussian beam analysis. Topics to be addressed include the derivations of the optical transfer function (OTF) and impulse response of the scanning holographic recording system, reconstructed image resolution and magnification, methods of carrier frequency hologram generation and experimental verification of the recording technique based on careful measurements of a hologram corresponding to a simple transmissive slit. Furthermore, computer simulations are presented pertaining to the incoherent nature of the …

The Use Of A High Level Cfd Code In Engineering Education, J.E.S. Venart, P. Lemieux, A.C.M. Sousa, D. Tatchell

Mechanical Engineering

An advanced multipurpose Computational Fluid Dynamics (CFD) code, FloSYS, developed for use in a CAD/CAE environment has been utilized in undergraduate and graduate courses in heat transfer. Problems are introduced at an introductory level in: -steady 2- and 3-dimensional conduction, -transient 1-, 2-, and 3-dimensional conduction, -free convective cavity flow with conjugate heat transfer, and -turbulent flows with heat transfer. More sophisticated problems, related to the use of porous media concepts for modelling heat exchangers, and compartment fire modelling are introduced at a more senior level. After one year's experimental use, the CFD code is being recommended for use in …

Tensile Strength Of Welded Connections, Wei-Wen Yu, Roger A. Laboube

CCFSS Library (1939 - present)

PREFACE The tensile strength of an arc spot weld is given only limited attention in the current edition of the AISI Specification for the Design of Cold-Formed Steel Structural Members. To broaden the design engineer's understanding of the behavior of arc spot welds, and to expand the specification's application for arc spot welds, the American Iron and Steel Institute, in 1989, initiated a research study at the University of Missouri-Rolla. The UMR research consisted of a comprehensive literature review, and experimental study which comprised of over 260 individual connection test specimens. The test specimen selection enabled the investigation of the …

Flexural Behavior Of Web Elements With Openings, Roger A. Laboube, Wei-Wen Yu, K. D. Batson

CCFSS Library (1939 - present)

INTRODUCTION The purpose of this phase of the research has been to investigate the flexural behavior of C-shaped members with web openings. Three common industry standard C-sections were tested as outlined in the first progress report. The web openings were located at 24 inches on center as illustrated in Fig. 1. Each test specimen was subjected to two point loads until the ultimate flexural strength of the member was obtained. This report summarizes the test procedure and results of the research to date.

Energy Use In Attached And Detached Residential Developments: Survey Results, Florida Solar Energy Center, Robin Vieira

FSEC Energy Research Center®

The relationship between land use, density, dwelling types and energy use in Florida has never been comprehensively examined. Few people consider both energy used in housing and energy used for local transportation. Florida state officials and some land planners have called for compact urban growth to reduce traffic congestion and travel distances. However, energy is rarely mentioned in these arguments. Local governments are trying to respond to the state's concern for compact growth. Developers, on the other hand, are concerned with meeting the local regulations. Unfortunately, energy use is seldom considered and there is little data available to guide decision …

Investigation Of Air Distribution System Leakage And Its Impacts In Central Florida Homes, Florida Solar Energy Center, James B. Cummings

FSEC Energy Research Center®

Testing for air leakage in air distribution systems was done in 160 central Florida homes. Tracer gas tests found that infiltration rates were three times greater when the air handler was operating that when it was off, indicating that there are large leaks in the air distribution system. Infiltration averaged 0.91 air changes per hour (ach) with the air handler (AH) operating continuously and 0.28 ach with the AH off. Return leaks were measured by tracer gas and found to average 10.7% of AH total flow. House airtightness, in 99 of these homes, determined by blower door testing, averaged 12.7 …

High-Frequency Electrooptic Fabry-Perot Modulators, R. J. Simes, R. H. Yan, C. C. Barron, Dennis J. Derickson, D. G. Lishan, Judy R. Karin, L. A. Coldren, M. Rodwell, S. Elliott, B. Hughes

Electrical Engineering

Electrooptic modulators built from GaAs/Al_xGa_1-xAs Fabry-Perot cavities operating up to 6.5 GHz are reported. The measured frequency response agrees well with the one predicted using an equivalent circuit model derived from high-speed electrical measurements. The parasitic capacitances have been reduced to approximately 30 fF by fabricating the devices on semi-insulating GaAs substrates and integrating them with on-wafer bound pads which have dimensions compatible with microwave coplanar probes.

The Calendar - June 1991, Nova University

The Calendar

No abstract provided.

A Prolog System For Converting Vhdl-Based Models To Generalized Extraction System (Ges) Rules, Michael A. Dukes, Frank M. Brown, Joanne E. Degroat

AFIT Documents

With the advent of VHDL accurate documentation of hardware designs is a practical reality. In the past, schematics were typically used for documentation of hardware designs. However, these schematics would usually become obsolete as the hardware design was being constructed. Deviations in the hardware design would sometimes not be reflected in the schematics. For design groups, failure to update schematics could lead to different parts of a hardware design becoming incompatible. A system to ensure compliance of hardware with its VHDL documentation is presented in this paper. The system, vhdl2ges, is meant to help guide the development of hardware by …

Acuta Enews June 1991, Vol. 20, No. 6

ACUTA Newsletters

In This Issue

Panel to focus on fraud

Interactive video bandwidth

Aggregator requirements

Telex can still be useful

Penn State still pioneering

Positions availabe

Network Model Investigation Of Gas Transport In Bidisperse Porous Adsorbents, John H. Petropoulos, John K. Petrou, Athanasios I. Liapis

Chemical and Biochemical Engineering Faculty Research & Creative Works

A capillary network model consisting of a micropore network permeated by one of macropores of randomly varying size has been constructed. Although simplified (to keep computer space and time requirements low) in relation to a real bidisperse porous adsorbent or catalyst, it embodies the salient pore structural features likely to determine the gas-transport behavior of such porous solids. Suitable model calculations of Knudsen gas-phase and surface diffusion enabled us to (i) validate useful approximate methods for the more economical evaluation of network permeability and (ii) demonstrate certain important characteristic effects of nonrandom bidisperse pore structure on transport behavior and their …

High Frequency Scattering Code In A Distributed Processing Environment, Scott Suhr

Theses and Dissertations

Government agencies and academic institutions are very interested programming for concurrent processing to cut computer processing time. However, many of the world's problems have already been coded for conventional serial computers. This research demonstrates the feasibility of modifying existing serial codes for execution in a concurrent processing environment. A electromagnetic scattering prediction code known as NECBSC is incrementally modified to incorporated various levels of concurrent computing. The data processed by the code are completely independent, providing an avenue for data decomposition of the process. Portions of the data set are processed on each mode and the results combined for final …

Investigation Of Adaptive Controllers For Puma Trajectory Tracking, Daniel J. Sims

Theses and Dissertations

Two robust model-based controllers and two decentralized adaptive controllers are experimentally evaluated. Algorithm evaluation is motivated by the need for controllers with good high speed tracking under varying payload conditions. The test case is a PUMA-560 robotic manipulator operating over the standard test suite. The model-based controllers are made robust by the addition of either an auxiliary input term or an adaptive feedforward compensator based on Lyapunov Theory. The model-based auxiliary input controller (MBAIC) adapts the gain matrices used in computing an additional torque to be combined with model-based feedforward and PD feedback torques. The adaptive model-based controllers adapt the …

A Multiple Model Adaptive Estimator Using First And Second-Order Acceleration Models For Use In A Forward-Looking Infrared Tracker, Barbara J. Niblett

Theses and Dissertations

The performance of a multiple model adaptive estimator (MMAE) for an enhanced correlator/forward-looking-infrared tracker for airborne targets is analyzed in order to improve its performance. Performance evaluation is based on elemental filter selection and MMAE estimation error sizes and trends. The elemental filters are based on either first or second-order acceleration models. Improved filter selection is achieved by using acceleration models that separate the frequency content of acceleration power spectral densities into non- overlapping regions with second-order models versus the more traditional overlapping regions with first-order models. A revised tuning method is presented. The maximum a posteriori (MAP) versus the …

An Alternative Algorithm For Discrete-Time Filtering, Frederick H. Zeitz Iii

Theses and Dissertations

The discrete-time Kalman filter is a conditional mean estimator of the states of a linear stochastic process, conditioned on the previous state and current measurements. It assumes that the states and noise inputs can be represented as jointly Gaussian random variables. The influence diagram is a decision analysis tool. Under certain conditions, it can represent continuous, jointly Gaussian random variables. The conditioning order of the random variables may be changed (using Bayes' rule) so that any random variable can be conditioned on any other subset of random variables in the diagram. Under these conditions, an influence diagram can represent the …

Development Of A Personal Computer Simulation Program Of The Ln-94 Inertial Navigation System, Thomas E. Flynn

Theses and Dissertations

This thesis develops a simulation that emulates a Litton LN-94 INS. Real time simulation is achieved for a stationary navigation case and a straight-and-level flight trajectory are provided to exercise the simulation dynamics. The user interface is simple and requires little previous knowledge to operate. The communication link with the MILSTD 1553B bus provide a realistic environment in which to collect and analyze data. The simulation is processed on an 80386 IBM compatible personal computer. A 23-state INS error model is implemented and integration is performed by a fifth-order Kutta-Merson routine. The simulation is interfaced to a plotting routine and …

Experimental Evaluation Of Design Variables For Two-Dimensional Confined Jet Thrust Vector Control Nozzles, Timothy M. Hawkes

Theses and Dissertations

An experimental study of the axial and vectoring performance of two - dimensional (2-D) confined jet thrust vector control (CJTVC) nozzles was performed. The effects of adding secondary injection ports and changing exit height and secondary injection port location were studied on several 2-D CJTVC nozzles. The axial and vectoring performance results for these nozzles were measured over a range of pressure ratios. An analytical method for predicting flow separation was found to be applicable to these nozzles. Guidelines for designing 2-D CJTVC nozzles, that can be vectored using secondary injection, were established.

Bearing Capacity Analysis Of Pavements, Tommy C. Hopkins

Kentucky Transportation Center Research Report

A multilayered, mathematical model for analyzing the ultimate bearing capacity of soil subgrades and asphalt pavements is presented. Theoretical considerations and mathematical derivations of limit equilibrium equations, based on plasticity principles, for analyzing the ultimate bearing capacity of soil subgrades and partially completed asphalt pavements, and the extension of these equations to the analyses of asphalt pavements composed of multiple layers, are presented. The model is unique since shear strength parameters, Φ and c, (the angle of internal friction and cohesion, respectively) are used to describe each layer of material of the pavement structure and a factor of safety against …

Evaluation Of Modified Asphalt Mixtures, Kamyar C. Mahboub, Amy Simpson

Kentucky Transportation Center Research Report

The primary objective of this study was to conduct a comparative analysis on various modified asphalt mixture systems in order to determine their suitability for conditions that are commonly encountered in Kentucky.

Several modified asphalt mixture systems were selected for laboratory and field testing (one-mile long field test section on KY 80, Pulaski County). These systems included the following asphalt mixtures: Control, Vestoplast, Polypropylene Fiber, Gilsonite, PMAC #1, Polyester Fiber, and PMAC #2. Laboratory testing included: Marshall stability and flow, mixture air voids and density, indirect tensile strength, moisture damage susceptibility, freeze-thaw damage susceptibility, resilient modulus, and repeated load permanent …

Dna Mapping Algorithms: Abstract Data Types - Concepts And Implementation, Will Gillett, Liz Hanks

All Computer Science and Engineering Research

The conceptual aspects of and the implementation details of a set of self-identifying abstract data types (ADT) are described. Each of the ADTs constitutes a specific class of object, upon which a set of well-defined access functions is available. The intent of these ADTs is to supply a paradigm in which a class of object is available for manipulation, but in which the underlying implementation is hidden from the application programmer. Specific ADTs are the described in some detail. The tagged architecture used to achieve the self-identifying property of the ADTs is presented, and a set of required system-backbone access …

The Difficulty Of Random Attribute Noise, Sally A. Goldman, Robert H. Sloan

All Computer Science and Engineering Research

This paper studies the robustness of pac learning algorithms when the instance space is {0,1}n, and the examples are corrupted by purely random noise affecting only the instances (and not the labels). In the past, conflicting results on this subject have been obtained-- the "best agreement" rule can only tolerate small amounts of noise, yet in some cases large amounts of noise can be tolerated. We show the truth lies somewhere between the two alternatives. For uniform attribute noise, in which each attribute is flipped independently at random with the same probability, we present an algorithm that pac learns monomial …

Computational Learning Theory Lecture Notes For Cs 582 Spring Semester, 1991, Sally A. Goldman

All Computer Science and Engineering Research

This manuscript is a compilation of lecture notes from the graduate level course CS 582, "Computational Learning Theory," I taught at Washington University in the spring of 1991. Students taking the course were assumed to have background in the design and analysis of algorithms as well as good mathematical background. Given that there is no text available on this subject, the course material was drawn from recent research papers. I selected the first twelve topics and the remainder were selected by the students from a list of provided topics. This list of topics is given at the end of these …

Reactivities Of Some Aromatic Compounds At Supercritical Water Conditions, Chun-Cheng Tsao

Masters Theses

The goals of this study are the removal of nitrogen from the extraction products of coal by Supercritical Water and the development of an understanding of the reactions leading to this removal. Six model compounds with structures similar to the intermediates of the coal liquefaction processes were studied. Benzylamine generated toluene through hydrogen abstraction after the C-N bond rupture. To a lesser extent, the oxidation of the benzylic carbon took place leading to benzene formation. Both reaction pathways occurred with equal probability for benzylidenebenzylamine, producing comparable yields of benzene and toluene. Benzaldehyde generated benzene through the oxidation/decarboxylation sequence. Benzyl alcohol …