Digital Commons Network^™

Brewster And Pseudo-Brewster Angles Of Uniaxial Crystal Surfaces And Their Use For Determination Of Optical Properties, M. Elshazly-Zaghloul, R. M.A. Azzam

Electrical Engineering Faculty Publications

Brewster and pseudo-Brewster angles are defined for surfaces of transparent and absorbing uniaxial crystals parallel and perpendicular to the optic axis. Two Brewster angles of a transparent uniaxial crystal surface parallel to the optic axis, measured when the optic axis is oriented perpendicular and parallel to the plane of incidence, readily determine the ordinary and extraordinary indices N_o and N_e. N_o and N_e can also be obtained from two Brewster angles measured on a surface perpendicular to the optic axis in contact with two media of different refractive indices. Conditions for the existence of two …

A Pattern Analysis Algorithm For Wind Ambiguity Removal, Jaime R. Tormos

Electrical & Computer Engineering Theses & Dissertations

Some remote sensing devices, such as satellite microwave scatterometers, produce sampled wind vectors that are accurate in speed and streamline direction, but have a directional ambiguity of 180°. The extraction of information from the two dimensional wind vectors is readily handled using pattern analysis techniques. It is shown that there is sufficient information in the spatial relationships of the generated windstream vectors to recognize the driving meteorological wind patterns. This then leads to the resolution of the wind ambiguity problem. This thesis presents the development of a pattern analysis algorithm that generates a measure of the raw data set that …

Efficient Infrared Upconversion In Gap, M. A. Gundersen, T. A. Yocom, P. G. Snyder, P. F. Williams

P. F. (Paul Frazer) Williams Publications

Mechanisms for linear conversion of infrared to visible were investigated in extrinsic Gap. Efficient (1 %) conversion of 10 micron to visible was observed in GaP:Zn,O. Several device applications are discussed and a quantum counter scheme involving 111-V photocathodes is presented.

Constant-Psi Constant-Delta Contour Maps: Applications To Ellipsometry And To Reflection-Type Optical Devices, A.-R. M. Zaghloul, R. M.A. Azzam

Electrical Engineering Faculty Publications

Constant-psi constant-delta contour maps in the reduced angle-of-incidence-film-thickness plane that are useful in ellipsometry and in design of reflection-type optical devices are discussed. As a specific example, a contour map is given for the SiO₂-Si film-substrate system at the 6328-Å He-Ne laser wavelength.

Simple Powerful Tunable Single-Mode And Mode-Locked Tea Co2 Laser, R. A. Dougal, M. A. Gunderson, P. F. Williams

P. F. (Paul Frazer) Williams Publications

A simple method for constructing a single longitudinal-mode CO₂ laser that is tunable within individual rotational transitions is presented. Useful power levels, typically 0.3 J per pulse in a single-mode beam, are obtained from a single-stage device. Mode-locked output can also be obtained from the laser. In addition, design and construction of a local oscillator for making absolute in situ frequency measurements is described.

A Control Program And Operating System For A Three Joint Robot Arm On An Apple Microcomputer, Eric Henry Stelzer

Masters Theses

"A Robotics Operating and Control System for a three-joint robot arm model is presented. The general operation of the system in interfacing the robot to the operator is discussed. Kinematic equations for the robot are derived and commands available to the operator are covered in some detail. The operation of the Control System in moving the robot is explained. Finally, suggestions are made for further development of the system"--Abstract, page ii.

On The Uniqueness Of Solution Of Magnetostatic Vector‐Potential Problems By Three‐Dimensional Finite‐Element Methods, O. A. Mohammed, W. A. Davis, B. D. Popovic, T. W. Nehl, Nabeel Demerdash

Electrical and Computer Engineering Faculty Research and Publications

In this paper, particular attention is paid to the impact of finite‐element approximation on uniqueness and to approximations implicit in finite element formulations from the uniqueness requirements standpoint. It is also shown that the flux density is unique without qualifications. The theoretical and numerical uniqueness of the magnetic vector potential in three‐dimensional problems is also given. This analysis is restricted to linear, isotropic media with Dirichlet Boundary conditions. As an interesting consequence of this analysis it is shown that, under usual conditions adopted in obtaining three‐dimensional finite‐element solutions, it is not necessary to specify div Ā in order that Ā …

An Analytical Method For Quantifying The Electrical Space Heating Component Of A Cold Load Pick Up, Walter W. Lang, Max Darwin Anderson, David R. Fannin

Electrical and Computer Engineering Faculty Research & Creative Works

After an extended cold weather outage on a distribution circuit supplying a high saturation of electrical space heating, large transient overcurrent's persist for several hours because of the undiversified heating load. In this paper, the electrical space heating component of enduring demand is characterized by a smooth curve. Expressions are derived for the parameters of the curve in terms of the outage conditions and a statistical description of the residences. A method is suggested for using this characterization to determine the effects of a cold load pick up on the distribution circuit components. Copyright © 1982 by The Institute of …

Generalized Running Discrete Transforms, John A. Stuller

Electrical and Computer Engineering Faculty Research & Creative Works

This Paper Introduces a Generalized Running Discrete Transform with Respect to Arbitrary Transform Basea, and Relates the Generalized Transform to the Running Discrete Fourier Z and Short-Time Discrete Fourier Transforms. Concepts Associated with the Running and Short-Time Discrete Fourier Transforms Such as 1) Filter Bank Implementation, 2) Synthesis of the Original Sequence by Summation of the Filter Bank Outputs, 3) Frequency Sampling, and 4) Recursive Implementations Are All Extended to the Generalized Transform Case. a Formula is Obtained for Computing the Transform Coefficients of a Segment of Data at Time N Recursively from the Transform Coefficients of the Segment of …

Seeded Oscillatory Growth Of Si Over Sio² By Cw Laser Irradiation, G.K. Celler, L. E. Trimble, K.K. Ng, H.J. Leamy, H. Baumgart

Electrical & Computer Engineering Faculty Publications

Extensive seeded epitaxial growth of crystalline Si over SiO₂ was achieved by an oscillatory regrowth method applied to rectangular Si pads recessed into a thick SiO₂ film. Narrow (≃5 μm) via holes linked the pads with the bulk (100) Si substrate. Oriented single crystals propagated as far as 500 μm from the seeding area, following the long term advance of a scanned focused laser beam.

Applying Software Complexity Metrics To Program Maintenance, Kenneth Magel, Raymond Michael Kluczny, Warren A. Harrison, Arlan R. Dekock

Business and Information Technology Faculty Research & Creative Works

No abstract provided.

Conversion And Matched Filter Approximations For Serial Minimum-Shift Keyed Modulation, Carl R. Ryan, James H. Stilwell, Rodger E. Ziemer

Electrical and Computer Engineering Faculty Research & Creative Works

Serial minimum-shift keyed (MSK) modulation, a technique for generating and detecting MSK using series filtering, is ideally suited for high data rate applications provided the required conversion and matched filters can be closely approximated. Low-pass implementations of these filters as parallel inphase-and quadrature-mixer structures are characterized in this paper in terms of signal-to-noise ratio (SNR) degradation from ideal and envelope deviation. Several hardware implementation techniques utilizing microwave devices or lumped elements are presented. Optimization of parameter values results in realizations whose SNR degradation is less than 0.5 dB at error probabilities of 10-6. © 1982 IEEE

Electrical And Structural Properties Of P-N Junctions In Cw Laser Annealed Silicon, M. Maier, D. Bimberg, G. Fernholz, H. Baumgart, F. Phillipp

Electrical & Computer Engineering Faculty Publications

Depth profiles of the electrical quality of ion implanted and cw laser annealed p-n junctions in silicon are obtained for the first time by secondary ion mass spectroscopy. A comparison with the crystallographic properties of the surface and the junction as observed by Nomarski optical microscopy as well as cross-sectional and plan view transmission electron microscopy is made. Samples containing slip dislocations show better insulation and a lower reverse bias current across the p-n junction as compared to samples with a perfect surface in agreement with current-voltage characteristics. Small dislocation loops located at the junction are found to degrade the …

Polarimeter, Rasheed M.A. Azzam

University of New Orleans Patents

To measure characteristics such as density and particle-size distributions of a medium that interacts with light, a polarimeter simultaneously develops all 16 elements of the Mueller matrix by modulating polarized monochromatic light with a quarter-wave retarder operating at a predetermined frequency before transmitting it to the medium and then modulating the light leaving the medium with another quarter-wave retarder which operates at a frequency five times that of the predetermined frequency of modulation of the light transmitted to the medium. The light is electrically detected and provides a signal which may, by Fourier analysis, be broken into 25 terms. The …

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 …

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.

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.

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 …

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 …

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 …

Slip Dislocation Formation During Continuous Wave Laser Annealing Of Silicon, Helmut Baumgart

Electrical & Computer Engineering Faculty Publications

High-voltage electron microscopy (HVEM) has been used for the investigation of the defect structure in cw laser-annealed silicon. We report for the first time a (HVEM) analysis of the formation processes involved in the nucleation and glide of slip dislocations during epitaxial regrowth by cw laser annealing of ion-implantation damaged silicon layers. Based on the combined optical and HVEM observations a model of the dislocation generation and glide processes is presented.