Engineering Commons^™

A Simulation Study Of A Limited Sensing Random Access Algorithm For A Local Area Network With Voice Users, Robert M. Spillers

Retrospective Theses and Dissertations

The purpose of this work is to evaluate the perfonnance of a limited sensing random access algorithm in a local area network with voice users. Random access algorithms have proven to be very efficient in local area network environments with data users. However, in contrast to data packets, voice packets cannot be allowed to experience long delays, because of the requirement that a voice "data stream" must be played out at the receiver. If a voice packet does exceed its established maximum delay, it is discarded. This simulation study finds the number of voice users that a network can support, …

Bias Optimization For Noise Reduction In Focal Plane Arrays, Kirk B. Reiff

Retrospective Theses and Dissertations

A gain enhanced common gate transresistance circuit is typically used as the coupling circuit between detector and multiplexer in a focal plane array. At an operating temperature of 77 degrees Kelvin, the dominant noises in the system are shot noise and 1/f noise. The 1/f noise corner frequency of the CMOS amplifiers used in focal plane arrays can .be as high as 10 kHz. In this paper it is shown that the 1/f noise corner frequency contributed to the system noise by the amplifier is a function of the bias voltage applied to the photodiode detector. Specifically, as the reverse …

Evaluation Of Concrete Pavement Performance With Related Cracking And/Or Voids Under I-10 Concrete Pavement, Cecil R. Henderson

Retrospective Theses and Dissertations

Under existing concrete highway payments there are voids that develop because of the pumping action of the slabs. The presence of free water, curled slabs from temperature and moisture gradients, and heavy wheel loads combine to provide this problem. The result is pumping and erosion of the base material, nonuniform support of the pavement slab, and eventual breakup of the concrete slabs. Two methods of voids detection were utilized in this study to compare one against the other. The first method used the Falling Weight Deflectometer (FWD) and the second method used the Ground Penetrating Radar (GPR) unit. Deflection readings …

Applications Of Simulation And Animation In Facilities Planning And Design, William Joseph Mattingly

Retrospective Theses and Dissertations

Recent developments of simulation software have made computer simulation and animation popular system problem-solving techniques. One field that has many potential applications for computer simulation and animation is in the area of facilities planning and design. The purpose of this paper is to provide the facilities planner with information to assist in determining when, why, how and what simulation software should be implemented to solve facilities planning and design problems. Also, the usefulness of simulation and animation to the facilities planner is evaluated and areas for improving software for future application in facilities planning and design are identified. TO assist …

A Rapid Acquisition Technique For Direct Sequence Spread Spectrum Systems By A Pn Phase Multiplexed Correlator, Greg S. Rawlins

Retrospective Theses and Dissertations

With the proliferation of direct sequence spread spectrum (DSSS) systems in the communications arena, synchronization techniques that offer improved performance and higher speed are of great value to the spread spectrum designer and user. Matched filter approaches have gained momentum in recent years due to SAW filter technology, while sliding correlators have experienced slower development. This paper introduces a unique multi-phase correlator intended to decrease the mean time to acquire synchronization by exploiting properties of Gold codes and other pseudo-noise (PN) sequences. These properties are used to create a novel signal structure for the local correlator. A brief explanation of …

Extending The Power Bandwidth Of A Piezoelectric Bender Actuator, Jerrold Pavlinko

Retrospective Theses and Dissertations

Scanning mirrors are a control element used in electrooptical systems. A scanning mirror system is a position control system that directs an image to an optical receiver or projects the output of an optical source to a target. A scanning mirror, as part of an infrared image generation system, could be used to scan an array of infrared detectors with a television camera to produce a raster image. Conversely, a scanning mirror could be part of a laser engraving system where the mirror moves the laser beam across the surface of a material to engrave characters, drawings in the material.

Implementing Path Control, English Motion Commands And Off Line Programming On Minimover-5 Robot, Mark S. Chen

Retrospective Theses and Dissertations

According to Alan L. Porter and Frederick A. Rossini (1987), 50,000 robots are expected to be installed by year 2000. This increasing number of robots to be used in industry has lead to the need for skilled robot operators and programmers. However, to train this specific class of personnel using an industrial robot as a training tool can be expensive and dangerous due to the possibility of robot accidents. Therefore, in order to provide a safe, inexpensive, and effective training tool, the use of the Mini-Mover-5 educational robot is proposed. The MiniMover-5 has only a primitive programming capability. A use-friendly …

Analysis Of Flexible Pavement On The Basis Of Deflection Basins, Dinesh M. Kamath

Retrospective Theses and Dissertations

The pavement at research park called Research Parkway and Discovery Drive was found Deteriorated within two years of the construction. The need to evaluate the extent of the damage and the estimate of remaining life of pavement initiate the research study. The analysis presented in this report is based on the measurements of the surface deflections and the layered elastic theory. The life expectancy of the pavement can be estimated by the amount of pavement deflection developed within the pavement system. The parameters used in the analysis are the applied load, material of the pavement components and environmental effects. Trial …

Forced, Non-Linear Vibration Of Integral Shroud Turbine Blades, Michael K. Brown

Retrospective Theses and Dissertations

This thesis examines the forced, non-linear vibration of integral shroud turbine blades. The shroud of this type of blade is integral with the foil and root. During turbine operation small gaps are generally present between adjacent shrouds. If the amplitude of blade vibration is sufficient, adjacent shrouds will contact. This contact creates a dynamic non-linearity. A complete row of blades is considered in the analysis. The Ritz averaging method is used to develop an approximate displacement solution. Frequency response curves for a representative turbine blade are presented in the usual format.

Numerical Solutions Of Continuous Wave Beam In Nonlinear Media, Jeffrey Huang

Dissertations and Theses

Deformation of a Gaussian beam is observed when it propagates through a plasma. Self-focusing of the beam may be observed when the intensity of the laser increases the index of refraction of plasma gas.

Due to the difficulties in solving the nonlinear partial differential equation in Maxwell's wave equation, a numerical technique has been developed in favor of the traditional analytical method. Result of numerical solution shows consistency with the analytical method. This further suggests the validity of the numerical technique employed.

A three dimensional graphics package was used to depict the numerical data obtained from the calculation. Plots from …

Applications Of Artificial Intelligence In Military Training Simulation, Igor V. Golovcsenko

Retrospective Theses and Dissertations

This report is a survey of Artificial Intelligence (AI) technology contributions to military training. It provides an overview of military training simulation and a review of instructional problems and challenges which can be addressed by AI. The survey includes current as well as potential applications of AI, with particular emphasis on design and system integration issues. Applications include knowledge and skills training in strategic planning and decision making, tactical warfare operations, electronics maintenance and repair, as well as computer-aided design of training systems. The report describes research contributions in the application of AI technology to the training world, and it …

Design Of A Lens System For A Structured Light Projector, Rick Joe Johnson

Retrospective Theses and Dissertations

Code V, an optical design program, was used to design a lens for a three-dimensional mapping application. The purpose of the lens system is to project an array of spots of light onto the object of interest. The size of the projected spots can be used to determine the distance from the lens to the object. The design criterion for this system was a 2% accuracy of position with a two lens system. The use of anamorphic and aspheric surfaces was also investigated as a means to improve the design performance.

Real Time Signal Processing Using Systolic Arrays, Jack Boulay

Retrospective Theses and Dissertations

This thesis discusses and presents the design of systolic arrays used in modern real time signal processing. A methodology to map a given algorithm into a systolized VLSI implementation is described. The architectural alternatives for a given signal processing algorithm are discussed and investigated at a function level using a simulation package that has been developed using the “C” programming language. The similarities and differences between wavefront array processors and systolic array processors are presented.

Versatile Gasdynamics Computer Program For One-Dimensional Isentropic Rayleigh And Fanno Flows, Robert Kenneth Smith

Retrospective Theses and Dissertations

The purpose of this research report is to discuss the development and results of a computer program (GASDYNAMICS) that solves a variety of compressible one-dimensional (1-D) steady gas dynamics problems utilizing the algebraic equations that result from the governing differential equations assuming perfect gas condition. This report shows how the governing differential equations that are derived from the ideal gas law, the definition of Mach number and the fundamental conservation laws of mass, energy, and momentum can be developed into their algebraic forms when additional simplifying assumptions are made.

GASDYNAMICS solves problems for either a converging or a converging –diverging …

Motion And Intrusion Detection Using A Pyroelectric Detector, Randy R. Fields

Retrospective Theses and Dissertations

The purpose of this paper is to describe a device that passively detects the presence of a warm-bodied object in a specified area. The detecting device used is a pyroelectric detector with an integral optical filter. By focusing infrared radiation generated by the object onto the detector, the resulting temperature change is converted to a voltage and then amplified. Modulation of the incoming radiation is accomplished by a rotating disk whose speed of rotation is dynamically controlled by a microprocessor. The resulting detector response is filtered and converted to a DC level. The signal is then passed through an analog-to-digital …

Diffraction Modelling For Saw Devices On Anisotropic Substrates, Melanie A. Roberts

Retrospective Theses and Dissertations

This thesis presents two approaches to solving the diffraction problem for SAW devices on anisotropic substrates. Diffraction is a nonlinear second-order effect which alters SAW performance, and some of the difficulty in predicting the actual effect is the anisotropy of acoustic materials, which makes the Fresnel Integral solution non-trivial. An accurate model for diffraction effects will allow compensation to be made without iterations in expensive and time consuming fabrication and testing processes, especially since it is difficult to isolate diffraction from other second-order effects. Of the two methods of modelling, one is a Fresnel Integral evaluation approach, and the other …

Remote Data Acquisition And Error Analysis Of The Scattering Parameters Of Quartz Crystal Devices, Sallie Layton Douglas

Retrospective Theses and Dissertations

A two-port device can be described by the incident and reflected voltages at each port. The parameters used in this description are known as scattering parameters. Accurate measurement of the values are thus important in device evaluation and network design. Limitations arise with the measurement capability of the equipment. In order to reduce these limitations, the data acquisition is controlled remotely by a computer program. The program also offers an error correction analysis of the measurement results. The measurement setup and basic approach are discussed as well as the techniques of normalization and calibration of each scattering parameter. The computer …

Design And Analysis Of A Voice Band Qpsk Modem, John F. Doud

Retrospective Theses and Dissertations

The objective of this paper is to design and construct a modem using the Quadrature Phase Shift Key digital modulation technique. The modem is designed to transmit information over a telephone line at the rate of 1200 bits per second subject to noise and imperfect channel response in the form of magnitude and delay distortion. The device is constructed using CMOS logic to minimize power consumption. To analyze the design with respect to the above constraints, it was necessary to build a pseudorandom bit sequence generator and correlator, a variable magnitude white noise generator and a digital error detector/indicator.

Two Point Resolution Of A Defocused Multi-Aperture System Eyelet, Steven A. Marlow

Retrospective Theses and Dissertations

Multi-aperture optical systems based on the insect eye offer an alternative to the common optical system based on the human eye. Some of the advantages of a multi - aperture system include the ability to perform parallel processing, have super resolution and have available large amounts of system redundancy.

An individual eyelet of a multi-aperture system consists of a gradient index lens coupled to optical fibers which transfer the incident light on the lens to individual detectors.

A mathematical model of an individual eyelet was developed. It is a flexible model allowing various system parameters to vary. Computer based algorithms …

The Design And Implementation Of An Interdigitated Directional Coupler For Use In Microwave Mixers, Golnaz Pourparviz

Retrospective Theses and Dissertations

The purpose of this thesis is to present a design for a balanced microwave mixer, operating in the X-band region(S-12 GHZ). The major emphasis of this work is on the coupling structure of the mixer. A 3-db interdigitated Lange coupler is designed, fabricated, and tested. The design obtained through numerical procedures is compared with that obtained with the TOUCHSTONE CAD package. A brief comparison between this coupler and other commonly used couplers is also presented. The diode circuitry of the mixer is discussed in detail, focusing mainly on the operation of the Schottky barrier diode, and finally a total layout …

Ada Tools For The Description And Simulation Of Digital Signal Processing Systems, Mark D. Happel

Retrospective Theses and Dissertations

While specialized hardware description languages allow for maximum capability and efficiency in a design automation system, the use of a general purpose language in the same role can make the system more available or more available or more practical for a larger set of users. This project demonstrates the use of ADA* for the description and simulation of small digital signal processing systems. Building on conventions and primitives proposed by Denyer and Renshaw, a simple subsystem was described in ADA and then tested with a small simulator also written in ADA.

* ADA is a trademark of the United States …

An Apparatus For The Measurement Of Dc Electrical Conductivity And Seebeck Coefficient Of Semiconductors As A Function Of High Temperature And Oxygen Partial Pressure, George Francis Carini Ii

Masters Theses

"A computer controlled apparatus for the measurement of dc electrical conductivity and Seebeck coefficient as a function of temperature and oxygen partial pressure has been developed. Thermocouples are in electrical and thermal contact with the ends of the specimen bar. This allows both Seebeck and four-wire electrical conductivity measurements to be made in situ. Environmental enclosure of the specimen allows measurements over a range of oxygen activities from 1 to 10^-18 atm. A discussion of the measuring technique with schematics of the apparatus and data retrieval system is made. Results for measurements in selected oxide ceramics are compared to …

The Development Of Glass-Ceramic Matrix Composites And The Crystallization Of Two Glass-Ceramic Matrices, William M. Carty

Masters Theses

"In order to develop ceramic matrix composites for high temperature applications, two glass-ceramic matrices, one an yttrium aluminosilicate (YAS), the other a magnesium aluminosilicate (cordierite), were chosen as possible matrix compositions. Two separate sets of experiments were performed. Specimens were hot pressed and heat treated then analyzed for the crystallization products and C.T.E. Specimens were also prepared containing commercially available ceramic fibers and coated ceramic fibers to investigate fiber/matrix interactions and the effect of fiber additions on the crystallization of the glass matrices. DTA was employed to approximate the crystallization temperature of the glasses and to determine the effect of …

Glass Fiber Reinforced Polycarbonate Composites, Wen Ching Hu

Masters Theses

"The purpose of this work was to develop a transparent glass fiber reinforced polymer composite material which is superior to the transparent unreinforced thermoplastic in mechanical properties but similar in optical clarity. Polycarbonate matrix composite specimens containing 0 to 40 wt% SK-12 glass fiber were studied, with mechanical and optical properties determined as a function of glass fiber content. The mechanical properties -- flexural strength and elastic modulus increased with increasing glass fiber content. The optical properties -- transmission and transparency decreased with increasing glass fiber content. The factors which influence the mechanical and optical properties were investigated"--Abstract, page ii.

Characterization Of The Fluid-Dynamic Mixing Of A Bottom Gas-Injected Channel Reactor Using Low-Temperature Modelling, Jay Bernett Gassel

Masters Theses

"Variables influencing the mixing in a single-phase (30.5 x 60 x 606 cm) and a two-phase (20 x 40 x 200 cm) channel reactor model were studied. Tracer and/or neutral density particle techniques were used to determine an eddy diffusivity, De, for the system(s). Three bubbler arrangements were investigated in the one-phase work. A separate apparatus was developed to withstand the corrosiveness of the tetrachloroethylene used in the two-phase work.

Both the electrical conductivity tracer technique and the neutral density particle technique were shown to be feasible experimental techniques for determining an eddy diffusivity in the systems studied. Decreasing liquid …

The Mechanical Properties Of The Bonne Terre Formation Dolostone According To Carbonate Facies And Moisture Conditions, Sweetwater Mine, Viburnum Trend, Southeast Missouri, Harvey Edwin Goodman

Masters Theses

"The mechanical properties of the Bonneterre Formation dolostone are critical to the design of underground mine openings at Ozark Lead Company's Sweetwater Mine, southeast Missouri. Host rock strength and elastic moduli, as affected by carbonate facies and varying moisture conditions, can influence rock stability in this multi-horizon mine.

Lead and zinc sulfide ores occur throughout the 350 foot-thick Bonneterre formation found in the mining area. Orebodies are mined in all four carbonate facies of the Bonneterre, including the (1) micrite (mudstone/wackestone) and shale facies, (2) the oolitic (packstone/ grainstone) facies, (3) the digitate stromatolite (boundstone) facies, and (4) the planar …

Causal Factors In The Hydration Susceptibility Of Periclase Aggregates, Chao-Min Cheng

Masters Theses

"The findings presented in this thesis are the result of a study of the hydration mechanism of pre-calcined periclase aggregates. It is hoped that these findings will provide the means to develop an economical, stable and hydration resistant layer on the surface of periclase aggregates by coating with appropriate chemical systems.

In the conduct of this study two sources of commercially obtained materials, Steetley 323, and China metal 90-10, supplied by the Quigley company, were characterized and treated with different concentrations of boron-containing water suspensions in order to impose an altered layer which would resist hydration.

Variables affecting hydration investigated …

Optimization Of Richardson's Shale Durability Rating System, John Dell Long

Masters Theses

"The two-cycle sieved slake durability test, performed on specimens initially oven-dried prior to testing, was determined to be the optimum slake durability testing procedure based on 12 variations of the test performed on 12 different shale types. The effects of changing slake durability testing variables was also studied.

Standard Proctor moisture-density and compaction-degradation tests were performed on 11 shales.

A modified version of the ultrasonic cavitation disaggregation test was developed and performed on 14 shales.

Richardson's shale durability rating equation was modified to include or reflect a data base of 14 shales, the results of the 20-min. ultrasonic cavitation disaggregation …

Performance Predictions For Oil Reservoirs Under Water Influx, Briareus Mitchell Wilkinson

Masters Theses

"The intent of this thesis is to develop a program that will give reasonable recovery predictions for oil reservoirs under water influx. The main advantage is to avoid the massive storage and computational requirements of numerical simulators while achieving roughly comparable results. There are many methods already in existence that have not received their full benefit, mainly because they were developed prior to the recent advances of the computer age. This thesis therefore brings some already proven methods together with new techniques in a program which, with the aid of the computer, stimulates new life in these methods. The main …

Property Survey Of Y₂O₃-Al₂O₃-Sio₂-MₓoY Glasses, Amy Lee Applewhite

Masters Theses

"The purpose of this work was to investigate the properties of Y₂O₃-Al₂O₃-SiO₂-M_xO_y glasses. Many M_xO_y components were tested, but TiO₂ and B₂O₃ proved the most interesting. Glasses containing 5 to 25 wt % TiO₂ were melted and found to have improved chemical durability and a higher refractive index and density than the eutectic Y₂O₃-Al₂O₃-SiO₂ starting glass. These glasses could be crystallized to form an opaque glass ceramic. Glasses containing B₂O₃ were formed by exchanging SiO₂ with B₂O₃ while holding the Y₂O₃ and Al₂O₃ content constant. The density, hardness, refractive index, transformation temperature, softening temperature …