Digital Commons Network^™

Photoluminescence In Spray-Pyrolyzed Cdte, Bernard J. Feldman, J. (Jack) L. Boone, T. (Thomas) Van Doren

Electrical and Computer Engineering Faculty Research & Creative Works

We report very intense photoluminescence in spray-pyrolyzed CdTe at 77 K. We also notice striking similarities in the luminescence spectra, decay, and temperature dependence between CdTe and other thin-film semiconductors, which we interpret in terms of recombination at defect sites in intergranular regions.

Contours Of Constant Principal Angle And Constant Principal Azimuth In The Complex Ε Plane, R. M.A. Azzam

Electrical Engineering Faculty Publications

For light reflection at a planar interface between two homogeneous isotropic media with complex relative dielectric function ε, we show that the constant-principal-angle contours are a family of semicircles, whereas the constantprincipal-azimuth contours are a family of (segments of) hyperbolas in the complex ε plane. We also find the exact envelope curve of both families and hence determine the domain of the ε plane of multiple (three) principal angles that is bougded by the envelope curve and the real axis. A unique and peculiar interface with ε = (5 - j√2)/27 is shown to have three coincident principal angles of …

Electrodeposition Of Photovolatic Cdte Films, Thomas P. Van Doren, Jack L. Boone, R. Engelken, Z. Maczenski

UMR-DNR Conference on Energy

No abstract provided.

Feasibility Study Of A Wind Energy Conversion System (Wecs) For The Sedgwick County Zoo, Robert I. Egbert, Scott S. Heide, Gary C. Thomann

UMR-DNR Conference on Energy

No abstract provided.

Cold Load Pick-Up: Quantifying The Electrical Space Heating Component, Walter W. Lang, Max D. Anderson, David R. Fannin

UMR-DNR Conference on Energy

No abstract provided.

The Bond Graph - A Power And Energy Modeling Concept, K. Sirivadhna, Earl F. Richards, Max D. Anderson

UMR-DNR Conference on Energy

No abstract provided.

Development Of A Small Computer-Based Power System Simulator For Economic Dispatch And Operator Training, James Liao, Max D. Anderson, Earl F. Richards

UMR-DNR Conference on Energy

No abstract provided.

Modes Of A Laser Resonator With A Retroreflecting Roof Mirror, Guosheng Zhou, Lee W. Casperson

Electrical and Computer Engineering Faculty Publications and Presentations

The self-consistent integral equation for the field distribution of the resonant modes in a resonator with a tilted retroreflecting roof mirror is solved. The field distribution in the direction of the roof can be described in terms of Hermite-Gaussian functions. The beam matrix for a retroreflecting roof is found, and a new type of resonator which does not need precise alignment is proposed.

Explicit Determination Of Thickness Of A Transparent Film On A Transparent Substrate From Angles Of Incidence Of Equal P And S Reflectivities, R. M.A. Azzam

Electrical Engineering Faculty Publications

No abstract provided.

Electromagnetic Modes Of An Inhomogeneous Sphere, Lee W. Casperson

Electrical and Computer Engineering Faculty Publications and Presentations

In many cases the electromagnetic modes of a sphere can be obtained exactly. Special simplifications occur when the conductivity, complex permittivity, and complex permeability vary only in the radial direction, and static and time dependent examples are discussed. With quadratic or Coulomblike permittivity variations, the wave functions resemble the quantum mechanical harmonic oscillator or hydrogen atom wave functions, and similar angular momentum operators are obtained.

Synthesis Of Gaussian Beam Optical Systems, Lee W. Casperson

Electrical and Computer Engineering Faculty Publications and Presentations

Systematic procedures are presented for determining the the optical components needed to obtain an arbitrary transformation of a propagating light ray or Gaussian beam.

Analysis Of Oscillations In Nonlinear Systems Using Multiple Input Describing Functions, Frederic Lee Swern

Dissertations

Sufficient conditions for oscillation as well as absence of oscillations are presented for a class of systems containing one lumped linear element and a differentiable nonlinearity. The results are obtained by estimating the error inherent in using a describing function analysis. Contraction type arguments are used to show common topological properties of the describing function solution and the balance of first harmonic terms of the system.

After discussing the describing function method, two theorems are presented regarding existence or nonexistence of oscillations from homotopic considerations. A graphical method for examining systems with power law nonlinearities is given using a parameter …

Investigations Of Gate Turn-Off Structures, Hans Werner Becke

Dissertations

Research and Development was done on gate turn-off devices. The aim was i) to improve turn-off capability without compromise of turn-on, on-state, and useful temperature range, ii) to implement "safe" turn-off.

A) The dependence of the electrical device characteristics on cathode width for an optimized vertical structure was determined. Fall times of 100 to 200 nsec and risetimes of <400 nsec were simultaneously obtained for average current densities of 53 A/cm² @ T_j = 125°C. From spreading resistance analysis the fast t_r and t_f response is shown to be a consequence of proper Au-distribution in the active device volume.

From transient analysis it is concluded that for safe …

Statistical Averaging In Position Determination By Holography Under Turbulence Conditions, Paul Aloysius Mcgovern

Dissertations

An investigation of several, disparate phenomena is conducted with the aim of developing a novel surveying system capable of overcoming the limitations imposed by turbulence in modern surveying. This method incorporates standard holographic techniques and time domain statistical averaging of survey data.

Some pertinent characteristics of atmospheric turbulence are reviewed, and the restrictions imposed on standard surveying practices by such turbulence are identified. A model for the turbulent medium is proposed on the basis of previous work and several theoretical results are summarized and extended.

On this basis the technical characteristics of the proposed technique are developed and each step …

A Critical Study Of Nonlinear Echo Phenomena, Monish Ranjan Chatterjee

Electrical and Computer Engineering Faculty Publications

The present thesis attempts to give a concise and critical account of the evolution of the echo phenomena over the last thirty years. Starting with spin and photon echoes, which were among the earliest to be observed and studied, the thesis explores the experimental findings and the models proposed in connection with the more contemporary echo experiments, viz. those involving electroacoustic or polarization echoes in single and polycrystalline piezoelectric materials and in powders. Although the investigations regarding the various mechanisms of short and long term echo formation are by no means complete, a coherent picture is beginning to emerge as …

Modes Of A Laser Resonator With A Retroreflective Mirror, Guosheng Zhou, Lee W. Casperson

Electrical and Computer Engineering Faculty Publications and Presentations

The self-consistent integral equation for the field distribution of the resonant modes in an inclined retroreflective grating resonator is solved in the limit of large Fresnel numbers. The transverse field distribution in the direction perpendicular to the grating grooves can be described in terms of Hermite-Gaussian functions provided that λ « d « w, where λ is the wavelength, d is the grating spacing, and w is the beam spot size.

Laser Broadening Ratio From The Multimode Oscillation Threshold, Lee W. Casperson

Electrical and Computer Engineering Faculty Publications and Presentations

Lasers with mixed line broadening typically oscillate in a single longitudinal mode for excitation levels only slightly above threshold. At high pump levels, less desirable multimode oscillation may sometimes occur. A procedure is described for using the multimode threshold as a sensitive measure of the broadening ratio, and GaAs is mentioned as an example.

A Method Of Modeling Multirate Two-Dimensional Recursive Digital Filters Author, Albert P. Gerheim

Electrical & Computer Engineering Theses & Dissertations

This dissertation presents a method of modeling two dimensional sampled data systems with two sampling rates in each dimension. This methodology is applied to the problem of synthesizing two dimensional velocity filters using one dimensional prototypes and multirate concepts.

The modeling method includes the replacement of scalar z-transforms of signals by vectors of polynomials, and the replacement of scalar z-transforms of impulse responses by matrices of polynomials.

The synthesis of velocity filters is accomplished through the use of coordinate transformations in the z-transform domain which skew the ω₁ -ω₂ axes on the unit bidisc. The filters synthesized using …

Multiple Scattering Of Protons And Deuterons By Thick Foils, D. R. Dixon, G. L. Jensen, S. M. Morrill, C. J. Connors, R. L. Walter, C. R. Gould, P. M. Thambiduria

Faculty Publications

Protons and deuterons from the Triangle Universities Nuclear Laboratory (TUNL) tandem Van de Graaff of energies 3.0, 4.0, and 5.0 MeV were scattered from foils of Al, Ni, Mo, and Ta having thicknesses of 6.14 to 47 mg/cm2. Multiple scattering angular distributions were measured using a position-sensitive detector to collect data at nine different angles simultaneously. Gaussian curves were fitted to the central points of the distributions and the Θ1/e angles thus derived are presented graphically. The data points are compared with calculations using a common method of determining multiple scattering angles. An empirical correction for extending this method into …

Proton Induced X-Ray Emission Analysis - A Complement To Analytical Methods Used In Environmental Studies, N. F. Mangelson, D. J. Eatough, N. L. Eatough, L. D. Hansen, M. W. Hill, M. L. Lee, L. R. Phillips, M. E. Post, B. E. Richter, J. F. Ryder

Faculty Publications

Particle induced X-ray emission (PIXE) analysis is a highly versatile method of element analysis. Thus it is well suited for use as a complement to other methods of analysis in experimental programs requiring both chemical and elemental analyses. This paper reports some results of two projects where PIXE was used in conjunction with titration calorimetry, ion chromatography, atomic absorption spectroscopy, gas chromatography/mass spectrometry, X-ray fluorescence spectroscopy and some other methods. The first is a study of sulfur chemistry in a copper smelter plume. Arsenic was found to be a conservative tracer of the plume and was used for calculation of …

A Site Evaluation For A Wind Generator At The University Of Northern Iowa, William A. Rosburg Ii

Graduate Research Papers

There is a need to develop alternative sources of energy other than our finite fossil fuel resources (Clews, 1975; Leckie, Masters, Whitehouse and Young, 1975). One possible area of great potential is the clean renewable energy in the wind. The World Meteorological Organization has estimated that there is a potential for producing 20 million megawatts of electricity from wind power (Clews, 1975). Although there are problems with cost, reliability, and its inherently intermittent nature, both government and industry are working to develop a wind technology that will help meet today's electrical energy needs.

An increased awareness by the general public …

High Voltage Powerline Injury Studies, A. Sances, S. J. Larson, J. F. Szablya, J. Derald Morgan, J. B. Myklebust

Electrical and Computer Engineering Faculty Research & Creative Works

Current pathways and reconstructions of human injury after contact with distribution powerlines are not well understood. The impedance, currents, and modes of tissue destruction are rarely known. Eight anesthetized hogs, weighing 68 to 90 kg, were used in studies with potentials ranging from 2,100 to 14,400 volts. Electrical contact was made between the hindlimbs, from the hindlimb to forelimb, and over other regions of the body. Currents from 4 to 70 amperes rms and impedances ranging from 130 to 477 ohms were measured. Phase angles up to 40° were observed. Copyright © 1981 by The Institute of Electrical and Electronics …

Verification Of The Kalman Conjecture For Systems Containing Numerator Dynamics, Abdelhamid Djebrane, D. Ronald Fannin

Electrical and Computer Engineering Faculty Research & Creative Works

The Kalman conjecture is shown to be true for certain systems of arbitrary order containing numerator dynamics. Simple restrictions on the system parameters are obtained such that the validity of the Kalman conjecture can be easily tested. Copyright © 1981 by The Institute of Electrical and Electronics Engineers. Inc.

Fast Transient Contingency Evaluation In Power Systems, Rodrigo S. Chamorro, Max Darwin Anderson, Earl F. Richards

Electrical and Computer Engineering Faculty Research & Creative Works

The problem of creating a practical computational tool to perform transient contingency analysis in a power system control center is considered. The computer program developed may be used in a control center computer where a state estimation program or a consistent set of load flow data is available. It can be run on a periodic basis over a previously specified contingency list, or it can be called by the system operator to analyze a particular contingency. The transient behavior of the system is evaluated based on a simulation technique widely acknowledged for its fast solutions. The method uses rapidly convergent …

A Performance Study Of A Microcomputer-Iimplemented Microcomputer-Implemented Fsk Receiver, Paul D. Stigall, Rodger E. Ziemer, Van T. Pham

Electrical and Computer Engineering Faculty Research & Creative Works

No abstract provided.

Microfit : A Gate Level Logic Simulator, Yacoub Abraham Alsaka

Theses and Dissertations

Today, gate logic simulation requires large computer facilities. This thesis demonstrates the ability to implement a gate logic simulator in a limited memory environment, specifically in a microcomputer system which usually has limited memory space; at the same time with a reasonable response time. This will permit the use of gate level simulation as a powerful design tool implemented with limited resources or with a desk-top microcomputer. The thesis discusses the development of the MICROFIT logic simulator. The MICROFIT would be used by the students and implemented on the LSI-11 Microcomputer Systems in the Assembly Language Laboratory at Florida Institute …

Performance Of Third Harmonic Ground Fault Protection Schemes For Generator Stator Windings, R. L. Schlake, G. W. Buckley, George Mcpherson

Electrical and Computer Engineering Faculty Research & Creative Works

The paper shows how the normally generated third-harmonic voltage can be used to protect the lower ten to twenty percent of generator stator windings against ground faults. A method of determining the applicability of the scheme to a given machine is described which takes into account the design of the generator and its externally connected apparatus. The effects of finite resistence ground faults are also investigated and other advantages of the scheme, such as protection of the neutral, are also highlighted. Copyright © 1981 by The Institute of Electrical and Electronics Engineers, Inc.

Chemical Spray Pyrolysis Of Cadmium Telluride., Alok K. Berry

Masters Theses

"Chemical spray pyrolysis is a technique for film growth which is of interest because of its potential for very large scale, inexpensive production of polycrystalline thin film semiconductor materials. Cadmium telluride shows promise as a base material for solar cell applications. Thin films of CdTe have been spray deposited on glass substrates from an aqueous solution containing CdC1₂, Teo₂ and a reducing agent. The films show a zinc blende structure and appear to be intrinsic. Microprobe analysis indicate an excess of Cd, but this is not detectable by X-ray diffraction. The photo absorption studies indicate a direct …

Optimization Of An Investment Strategy For The Mcdonnell Douglas Salaried Savings Plan., Richard Charles Seifert

Masters Theses

"An automated technique is developed to maximize the return on investments in the McDonnell Douglas Salaried Savings Plan. Continual guidance is provided to the participant as to the currently preferred type of investment within the Plan, and to the strategic t iming of withdrawals from the Plan. The decision criteria within the modelled system address the tradeoff s which result from the participant's past investment decisions, his current tax situation, alternative market conditions, withdrawal penalties and o the r Plan characteristics. Decisions are made on the premise that historic performance patterns will continue, though adaptive procedures are included to react …

The Design And Development Of A Human Interface For An Intelligent Terminal For A Process Control Industry, V. Rangarajan

Masters Theses

"A complete description of an intelligent Terminal to be used in a Process Control Industry is presented. The system software is discussed. An account of the hardware and software interfaces for the input devices, along with the description of the input devices, is included. The data base used in the system is described with an example. Future enhancements have been proposed."--Abstract, page iii.