Digital Commons Network^™

The Effect Of Thickness On Neuber's Rule For Estimation Of Fatigue Life, Shahram Elmi

Retrospective Theses and Dissertations

To predict the fatigue life of a notched member from a strain-life curve, the high strain concentration at the root of the notch must be known. For determining this high (post yield) strain, the Neuber’s Rule (for plane stress) and linear rule (for plane strain) can be applied. To investigate the accuracy of these method a notched member which is subjected to fully reversed cyclic loading is analyzed by the finite element method. Moreover, members with different thicknesses are analyzed with three dimensional elements, and a correlation between plane and three dimensional data is obtained. This correlation may be used …

Noise In Interferometric Sensors, Mark Phillips

Retrospective Theses and Dissertations

A noise analysis is conducted on an interferometric sensor employed in the study of underwater acoustic noise. Primary emphasis is placed on finding the output Signal to Noise Ratio of the sensor.

Once the initial problem of the type of noise is established, the analysis proceeds along fairly classical lines. Field equations establish the signal reaching the director. Linear filter analysis establishes the nature of the spectrum after passing through a lowpass filter. Finally, second moment theory is used to derive expressions for the output Signal to Noise Ratio.

It is noted that the random ocean noise introduced to the …

A One Step Collision Detection Method For Computer Graphics Programs, Gregory T. Eichner

Retrospective Theses and Dissertations

The topic of this thesis is a collection detection algorithm for use in computer programs dealing in three dimensional graphics. Collision detection is usually accomplished by breaking the movement into small steps and checking if a collision has occurred at each of these discrete steps. This method is a very time-intensive way to detect for collisions and therefore, inefficient for a system which typically moves in large increments. For this kind of system, a method could be developed which checks once for collisions without dividing the move into multiple small increments. The subject of this paper is an algorithm, developed …

Non-Linear Plane Stress Analysis Using The Finite Element Method, Habib Amirzadeh

Retrospective Theses and Dissertations

Purpose of the Study

The objective of this report is to check the Neuber and Linear rules, and to find the percent differences in comparison with the plane stress and plane strain solution using the non-linear finite element method. All the data are based on the maximum stress concentration where the crack forms and the material behaves non-linearly. This particular problem has been solved using ANSYS, which is a general purpose finite element program.

Life Prediction

Another purpose, which is not the main subject of this report, is to use the result from Neuber and Linear rules to predict the …

The Effect Of Winglet Twist And Toe Angle On The Drag Of A High Aspect Ratio Wing, Thomas T. Moore

Retrospective Theses and Dissertations

Winglets have been shown to significantly reduce the lift induced drag. Different parametric studies have identified important winglet characteristics, but none have examined effects on drag from varying winglet twist and toe angle. The purpose of this research report is to examine the drag reducing effect of winglet twist and toe angle on a transport type high aspect ratio wing.

By using a cost-effective three dimensional vortex-lattice program which included two dimensional profile drag, the effect of winglet twist was found to have a moderate drag reduction against an untwisted winglet for the same toe angle. For the wing-winglet configuration …

A Signal Conditioner For Speech Processing, Daniel K. Weir

Retrospective Theses and Dissertations

This thesis describes the design, implementation and testing of an analog signal conditioner for use in processing of speech signals. The signal conditioner provides gain and bandwidth control for the speech signal and also indicates the signal level. It is designed to be used in conjunction with a digital speech processor and has ports for a microphone or other signal source, an input signal monitoring device such as an oscilloscope, and interfaces to the digital speech processor. Signal bandwidth control is provided by a variable cutoff frequency lowpass switched capacitor filter, which is driven by a clock. In this thesis, …

Comparison Of Apodization Geometries For Bidirectional Surface Acoustic Wave Transducers Based On Efficient Track Modelling, Armando J. Vigil

Retrospective Theses and Dissertations

Apodization, or spatial overlap weighting, is a common tap weighting technique for Surface Acoustic Wave filter transducers. The two most common apodization strategies are beam centered and slant centered overlap weighting. Two lesser known apodization geometries are beam spread overlap weighting and generalized distance weighting.

A wide variety of SAW transducer weighting techniques are described. Analysis is focussed on the four apodization geometries listed above. An efficient track based modelling system is developed in order to accurately solve for the acoustic radiation profiles, apodization loss and frequency dependent acoustic conductance. This modelling system becomes the foundation for a set of …

The Application Of Systolic Architectures In Vlsi Design, Steven V. Manno

Retrospective Theses and Dissertations

Very large scale integrated (VLSI) circuit technology has offered the opportunity to design algorithms and data structures for direct implementation in integrated circuits. In order to take full advantage of this opportunity, the designer must understand the geometric limitations of the technology. Because the interconnections between components in a VLSI circuit are costly in both chip area and performance, the designer must consider the complexity of the data paths between components when selecting algorithms and architecture.

Systolic architectures offer a way to implement massively parallel special-purpose systems in VLSI circuits while minimizing costly interconnections between processing components. In a systolic …

Apodization Of Surface Acoustic Wave Three Phase Unidirectional Transducers, Benjamin P. Abbott

Retrospective Theses and Dissertations

This thesis presents an introduction to surface acoustic wave (SAW unidirectional transducer (UDT) apodization. An unbalanced apodization structure is described. The structure is shown to suffer from an unbalanced capacitive effects, significant apodization losses and passband ripple. A balanced UDT structure is developed for the purpose of improving performance and minimizing undesirable effects associated with the unbalanced structure.

Each apodization structure is analyzed and compared using a typical impulse response of a SAW transducer. The analysis is accomplished using SAWCAD2, a unidirectional Surface Acoustic Wave Computer Aided Design FORTRAN-77 program developed at the University of Central Florida. Having shown the …

Simulating The Thermal Behavior An Earth-Stationed Satellite Terminal, Anthony M. Jacobi

Retrospective Theses and Dissertations

Lumped parameter modeling using finite differencing, form the basis for a C language simulation of a thermal system. The study of the earth-stationed satellite terminal includes an introduction to the system, derivation of the governing equation, development of a simulation, and a comparison of the results to empirical data.

The analysis is undertaken with emphasis on the worst-case thermal environment, and with determination of the cooling loads and transient response as primary goals. Comparing the predicted cooling loads to empirical data, and previous analyses, indicates an accurate simulation has been constructed. The computer models are offered as an alternative method …

A Colpitts Oscillator Design Technique Using S-Parameters, Timothy K. Johnson

Retrospective Theses and Dissertations

This research report describes a method for designing a Colpitts oscillator using S-parameters. The oscillator components are grouped into three functional blocks: 1) an unstable active network (which includes the transistor, feedback capacitor, and input resistor); 2) an output matching network (which includes the inductor, tuning capacitor, and load); and, 3) an input matching network (which consists of the remaining tank capacitor). This configuration not only satisfies the standard Colpitts oscillator topology, but allows the use of three simple criteria (based on the network S-parameters) to predict oscillation. A computer program was developed to calculate specific tank component values based …

The Effects Of Trace Organic Carbon On Aluminum Solubility, Fernand J. Tiblier

Retrospective Theses and Dissertations

Alum jar tests were performed on raw portable waters of varying TOC. Parameters monitored include alum dose, pH and mixing conditions. Finished waters were analyzed for residual aluminum, residual TOC and hardness in order to investigate the effects of TOC on aluminum residual as would be encountered by alum coagulation and lime softening process in practice.

Three-dimensional graphs of residual aluminum, residual TOC and pH were constructed to illustrate the relationship among these measured parameters for the different sources. Statistical analyses were conducted to verify aluminum-organic complexation at reduced alum dosages for varying TOCs; initial TOC, reaction pH and dose …

The Hydrology And Solids Removal Efficiency Of A Detention Pond With Groundwater Inflow, Cameron A. Boss

Retrospective Theses and Dissertations

Most recently, research on stormwater detention ponds has focused on designs and operations that will improve the water quality of the discharge. Historically stormwater detention ponds were used to reduce the rate of runoff from the watershed area of using temporary storage to attenuate flow rates.

The study site was located near Orlando, Florida, and consisted of a detention pond, namely Lake Angel, which received stormwater runoff from a 131-acre area. Hydrologic data such as precipitation, runoff, and pond outflow were measured at the site. Total and suspended solids data for the pond outflow and stormwater runoff also were collected …

Root Locus Plotter For A Dual Tank System Under Feedback Control, John M. Decatrel

Retrospective Theses and Dissertations

A root locus graphics routine was written in Turbo Pascal for the analysis and design of a linearized dual tank control system. The routine is a subprogram to be incorporated with an editor written by L. Fadden. This editor allows for the saving and changing of parameters to the system.

The dual tank system is a good example for classical feedback control analysis. A brief description of the process and system is presented. The system may be described by linearized differential and algebraic equations. From these, a characteristic equation is derived, which gives rise to the root locus. The root …

Control Of A Nonlinear System By Linearization, Drew D. Nelson

Retrospective Theses and Dissertations

In today’s linear control systems, exact solutions can be obtained by the use of Laplace Transforms in the frequency domain. In dealing with nonlinear systems, exact solutions are not always achievable. For this reason, it is necessary to linearize the system and then apply frequency response methods.

This paper shows the comparison of a nonlinear system with the linearized model of the same system. For both proportional and proportional-integral control, the response to a unit step change in the set point showed minimal difference between the linearized and nonlinear system.

The Secant-Corrector Spectral Iterative Method For Analyzing Scattering From Planar Periodic Surfaces, Robert Middelveen

Retrospective Theses and Dissertations

The secant method is applied to an iterative algorithm of electromagnetic scattering from planar surfaces with periodic structure. The theory of convergent solutions for iterative techniques is discussed and examined. The Secant method is applied to the spectral iteration approach to accelerate and assure convergence of the basic iterative scheme. The derivation of the method as applied to surfaces containing parallel thin wire gratings is presented, and the conditions for achieving convergence are explored. This new method is also applied to gratings made of coated wires. The reflection characteristics of the grating as a function of wire spacing, wire conductivity, …

A Pool Boiling Map: Water On A Horizontal Surface At Atmospheric Pressure, O. Burr. Osborn

Retrospective Theses and Dissertations

The purpose of this study was to develop a boiling map for liquid water at an atmospheric pressure. The map indicates the type of pool boiling phenomenon will initially occur in terms of the bulk temperature of the liquid and the interfacial contact temperature. The geometry studied was that of a flat horizontal plate with boiling incipient from the upward facing surface.

Previous analytical and experimental studies have been conducted concerning pool boiling. Several of these studies are summarized in this thesis and it is seen that there are gaps and limitations in the existing state of knowledge. Therefore, further …

The Application Of Expert Systems To Automated Storage And Retrieval, Robert E. Mcdonald

Retrospective Theses and Dissertations

This report discusses the major functions, decisions, and strategies of automated storage and retrieval systems (AR/RS). The report surveys the essential features of expert systems and discusses how they can be applied in automated warehousing environments. A blackboard expert system architecture was examined and found to be a flexible and responsive control system for automated warehousing applications. A simple AR/RS expert system was constructed using an expert system software package. A warehousing simulation was performed which compared the expert system’s performance to a typical AR/RS control system. The expert system produced increased efficiency of operation because of the intelligent rules …

Electromagnetic Scattering From Stacked Gratings, Pok K. Kwan

Retrospective Theses and Dissertations

The theory of scattering matrices and microwave network analysis are employed to solve the problem of scattering from cascaded infinite periodic gratings. The total reflection and transmission coefficients are calculated as functions of angle of incidence, wire spacing for each grating, grating separation, wire thickness, and number of gratings that comprise the cascaded structure. Moreover, the problem of stacking dielectric slabs with periodic gratings is formulated and solved. In all cases, the Secant Corrector Spectral Iteration approach is used as a numerical method for calculating the desired currents and fields.

Finally, calculated values of the reflection and transmission coefficients are …

Pulse Width Modulated Adaptive Delta Modem Design And Analysis, Gregory L. Milne

Retrospective Theses and Dissertations

A unique design of a voiceband adaptive delta modem will be presented. The modulator utilizes a constant amplitude variable width pulse combined with the principles of delta modulation. This results in a modem that has lower amplitude distortion, requires less transmission channel bandwidth, and is less prone to slope overload than conventional adaptive delta modems. The design also allows the use of a simple single integration demodulator while maintaining fidelity.

The modem design and analysis is presented assuming a transmission channel which is bandwidth limited and amplitude limited.

Dynamic Systems Analysis Of A Vehicle Suspension System, Bruce M. Skeldon

Retrospective Theses and Dissertations

This research report deals with one system in a Computer Aided Instruction package in the Dynamic Systems and Control Theory fields for the college undergraduate students. It uses the computer to numerically solve the two degree of freedom equations of motion for a vehicle suspension system. Numerical solutions to the system differential equations are used to drive an animated display of the vehicle’s motion (vertical displacement and rotation about the center of gravity) on the video display terminal.

The Integration Of Computer Graphics With Video Disc Technology: An Application In Training, Fereidon Torkzadeh

Retrospective Theses and Dissertations

The major objective of the work outlined in this paper is to become familiar with the MOVIE.BYU graphic system from Brigham Young University to demonstrate its use in the generation of non real-time images for a typical pilot training application. The implementation is done by using the MOVIE.BYU graphics system, a VAX 11/750 digital computer, and RAMTEK 9460 system. This paper discusses how the images can be stored a frame at a time on a video disc for playback at the normal rate to portray a moving scene using a Panasonic video disc recorder and player, and a Sony video …

A Theoretical Evaluation Of Water Surface Changes In A Circular Reservoir, Hossein G. Tehrani

Retrospective Theses and Dissertations

The purpose of this project is primarily to develop an equation to estimate the time that it will take for the water surface to decrease to another depth in an inverted conical-shaped reservoir behind an earth dam by means of the falling head permeability concept. This equation can be applied to the earth embankment either with or without underdrain. Since the derived equation for time span is a complicated and tedious matter, a computer program has been developed for solving this equation.

The computer program is written in BASIC language and executed on a Tektronix 4051 microcomputer. Primary effort has …

The Effect Of Detention Period On The Clarification Efficiency Of Nitrified Activated Sludge, James C. Boyd

Retrospective Theses and Dissertations

Proper performance of the final clarifier in the activated sludge process is vital to total system efficiency. Inadequate clarification can adversely affect substrate removal efficiency due to the biochemical oxygen demand exerted by solids lost in the clarifier effluent. Detention period is one factor which influences clarification performance and thus is of interest to the designer engineer. Also of interest is the relationship between detention period and rising sludge conditions in the clarifier, which can lead to a deterioration in clarification efficiency. Rising Sludge conditions are believed to be caused by the denitrification of nitrified activated sludge in the final …

Phase-Locked Loop Based Oscillator Phase Noise Measurement Technique, Luis M. Jimenez

Retrospective Theses and Dissertations

Oscillators play an important role in the performance of various radio frequency (RF) systems. The generation of stable carrier and clock frequencies is necessary at both the transmitter and receiver ends of a communication system. Phase noise is the parameter used to characterize an oscillator frequency stability. This thesis introduces a phase noise measurement technique using a phase-locked loop. A 100 MHz Colpitt’s oscillator, for the phase noise source, was designed and built. The output of the oscillator was mixed down to 10 MHz, before a phase-locked loop extracted the phase noise information. Measurements were taken at RF frequencies using …

Optimizing Scanning Mirror System Performance Using Solid State Piezoelectric Actuators, Thomas J. Tomasetti

Retrospective Theses and Dissertations

The purpose of this thesis is to design a scanning mirror system using piezoelectric actuators. A dual-cantilevered bimorph electromechanical coupling is presented, which maximizes the amount of angular deflection possible with an applied field. Two types of feedback methods are employed: rate sensing, which provides resonance damping, and position sensing for increased bandwidth and decreased hysteresis. A prototype system, including the actuator and feedback mechanisms, is developed. Its performance compares favorably with its model and is capable of plus and minus five degrees of angular deflection with a bandwidth of 300 Hertz.

A Survey And Analysis Of The Beginning Teacher Program In Florida And Its Relationship To Effective Education, Joanne Mullins Olson

Retrospective Theses and Dissertations

This study was conducted to determine whether there were significant factors contributing to a teacher's ability to perform effectively in the classroom. An approximate 5% stratified random sample was selected from 9,401 possible subjects in Florida's Beginning Teacher Program between 1982 and 1985. A comparison of descriptive and reportive data was performed for teachers who completed and teachers who did not complete the program.

Statistical measures included the use of contingency tables, chi-square statistic, frequency distributions and t-tests. Results suggested that a teacher's possibility of successfully completing Florida's Beginning Teacher Program was influenced by the participant's age, grade point average, …

Perfect Numbers And Mersenne Primes, Barry A. Delello

Retrospective Theses and Dissertations

No abstract provided.

Development And Testing Of A Heuristic Line Balancing Program For A Microcomputer, Dean B. Creech

Retrospective Theses and Dissertations

Development, operation, and testing of a heuristic line balancing program for a microcomputer are discussed. Tasks are grouped into work stations along an assembly line such that the number of work stations required is minimized.

The model is built primarily using the Hoffman (1963) procedure with modifications described by Gehrlein and Patterson (1975). For purposes of comparison the Rank Positional Weight technique (Helgeson and Birnie, 1961) is also included in the model.

Testing included thirty-seven different balances using problems from the literature. For each balance, both Rank Positional Weight and Hoffmann solutions were obtained in the forward and reverse directions. …

Separation Plane Priority In Computer Image Generation, Keith A. Stump

Retrospective Theses and Dissertations

Flight simulators are devices in which air crews can be trained without the use of actual aircraft. Potentially dangerous maneuvers, such as air-to-air refueling, and destructive exercises, such as evasive action from weaponry or aerial dogfights, can be practiced repeatedly with no risk to pilot or crew. Flight simulators are cost effective since the fuel costs associated with training pilots in actual aircraft can be excessive. Flight simulators offer an alternate training method with reduced cost. The task of a visual flight simulator is to present the trainee with scenes representative of those that would be seen if the actual …