Digital Commons Network^™

Interfacial Electrical Properties Of Ion-Beam Sputter Deposited Amorphous Carbon On Silicon, A. Azim Khan, John A. Woollam, Y. Chung, B. Banks

Department of Electrical and Computer Engineering: Faculty Publications

Amorphous, “diamond-like” Carbon films have been deposited on Si substrates, using ion-beam sputtering. The interfacial properties are studied using capacitance and conductance measurements. Data are analyzed using existing theories for interfacial electrical properties. The density of electronic states at the interface, along with corresponding time constants are determined, and the density of interface states is unusually low for an as yet unoptimized

Radio-Frequency-Excited Carbon Dioxide Metal Waveguide Laser, Jonathan Gary Grossman, Lee W. Casperson, O. M. Stafsudd

Electrical and Computer Engineering Faculty Publications and Presentations

A new type of waveguide laser is described in which a single-surface concave metal waveguide also doubles as the grounded electrode in a radio-frequency-excited gaseous discharge. The laser’s output modes and spectrum have been studied theoretically and experimentally for cw CO₂ operation of the laser. Overall operating efficiency and mode stability are comparable with those of conventional dielectric waveguide CO₂ lasers, and advantages of the metal waveguide laser include convection cooling, intracavity mode control, and partial self-alignment.

A Master Clock For The Speed School Impulse Clock System Using Wwv Time Information, John E. Pfeifer Jr.

Electronic Theses and Dissertations

Since approximately February of 1979, the Speed School impulse clock system has not functioned due to a worn-out master clock that was never replaced because of a lack of fund. For this thesis project, a solid-state master clock that performs the same functions as the old mechanical master clock was built for less than $200. The new clock features accuracy traceable to the National Bureau of Standards, automatic reset after a power-down and subsequent power-up, and a daylight savings time provision. A decoder that recovers time information broadcast by radio station WWV from Fort Collins, Colorado was built and interfaced …

Time-Resolved Two-Dimensional Imaging Of Ground-State Species Using Laser-Induced Fluorescence, R. A. Dougal, P. F. Williams, D. C. Pease

P. F. (Paul Frazer) Williams Publications

Laser-induced fluorescence has been employed to obtain two-dimensional images of the spatial distribution of a vapor in the ground state with nanosecond resolution. The method has a wide range of potential applications, as it can be used to observe any species which has energy levels accessible to tunable laser systems. In the application we describe, aluminum vapor was observed jetting from spark gap electrodes and diffusing throughout the gap volume.

Broadband Base Isolated Asymetrically Fed Vhf Antenna, Peter Edward Cunningham

Dissertations

Antennas presently being used for vehicular military VHF communications are narrowband. New generation frequency hopping radios, however, require broadband antennas. The antenna must be base isolated in order to reduce undesirable pattern nulls and impedance variations caused by currents induced on the support structure. Physical constraints limit the antenna length to three meters while operating from a frequency of 30 MHz to 88 MHz.

To satisfy the above requirements a model of a broadband, base isolated, cylindrical antenna less than three meters long was analyzed and built. Equations for the current distribution as a function of the physical parameters were …

The Photovoltaic Cell: History, Operation, Current Technology, Marc L. Luksetich

Graduate Research Papers

Historically, practical applications of solar cells were of single crystal silicon material (Rauschenbach, 1980). In the mid 1970s, the U.S. Government actively began to subsidize solar cell development and use (Maycock & Stirewalt, 1981). This funding provided a major contribution for expanded research, development, and markets. Consequently, manufacturing and final-product costs have been reduced with a corresponding increase in solar cell efficiency (Merrigan, 1982). The main objective of this study was to analyze literature from photovoltaic cell manufacturers regarding their current production methods, materials, and uses, and to report the findings.

Single-Reflection Film—Substrate Half-Wave Retarders With Nearly Stationary Reflection Properties Over A Wide Range Of Incidence Angles, R. M.A. Azzam, M. Emdadur Rahman Khan

Electrical Engineering Faculty Publications

The complex reflection coefficient for the p polarization of a transparent film on an absorbing or transparent substrate can be made equal to the negative of that for the s polarization, and hence the film—substrate system acts as a half-wave retarder (HWR), by proper selection of film refractive index N₁, film thickness d, and angle of incidence Φ. This condition, which generally holds only at normal incidence, becomes possible at oblique incidence also if N₁ is within a certain range, 1 < N₁ < N̂₁ . For a given substrate and given N₁, …

Computer Aided Analysis Of Electroencephalographic Waveforms, Edward Tadeusz Polkowski

Theses

An approach to analysis of EEG waveforms is described. The procedure utilizes a PDP -11 computer to perform a Fast Fourier Transform on four channels of data simultaneously. The transforms are done in real time and. the results are plotted in a manner which allows the operator to easily determine the major background activity and to check for left-right symmetries in brain waves. Patient data is used to verify the computer output against actual clinical diagnoses.

Blood Pressure Signal Simulation In An Artificial Circulation System, Shaw-Jyh Shin

Theses

The major objective of this thesis is to produce a desired pressure waveform in an artifical circulation system by using a Z-80 microcomputer controlled stepper motor. This will simulate the desired blood pressure waveform in the human body and can be used for clinical application.

A microcomputer simulation was used for setting up an electrical circuit model to represent the artificial circulation system as well as for finding out the relationship between motor speed (piston displacement) and pressure waveform.

Using this techniques, a desired pressure waveform which represents the blood pressure waveform in the human body can be obtained.

Moment Method Solution Of The Time-Dependent Transport Equation To Describe The Scattering Of Gaussian Plane Wave Pulses By A Forest, Nack Yang Cho

Theses

The time dependent transport equation is used to study the transmission of periodic pulses through a forest. The forest is assumed to occupy a half-space region, to be statistically homogeneous and to scatter energy isotropically A periodic sequence of Gaussian plane wave pulses is assumed to enter the forest normally from free space. The transport equation is solved by the moment method using triangular expansion functions. Numerical results indicate the dependence of the incoherent intensity on penetration depth, observation angle, albedo and pulse repetition rate.

Complex Reflection Coefficients For The Parallel And Perpendicular Polarizations Of A Film-Substrate System, R. M.A. Azzam, M. Emdadur Rahman Khan

Electrical Engineering Faculty Publications

The complex reflection coefficients R_v(ø,ζ) of a film-substrate system for the parallel (v = p) and perpendicular (v = s) polarizations are examined in detail as functions of the angle of incidence ø(0 ≤ ø ≤ 90°) and the reduced normalized film thickness ζ(0 ≤ ζ < 1). For definiteness, the reflection of light of wavelength λ = 0.6328 µm by the air–SiO₂–Si system is assumed. Families of circles that represent the constant-angle-of-incidence contours, their envelopes, and the associated constant-thickness contours ofR_p and R_s are all presented in the complex plane. Furthermore, the amplitude-reflectance and phase-shift functions, |R_v|(ø,ζ) and argR_v(ø,ζ) …

Saving Energy In Rural Maine : Or Who's Doing What On The Farm, Mane Department Of Agriculture

Maine Collection

Saving Energy In Rural Maine : Or Who's Doing What on the Farm

Compiled by Bettina M. Blanchard and Edited by Bill Seekins.

Maine Department of Agriculture, Food and Rural Resources, Division of Resources Development, Augusta, Maine, 1983.

Contents: List of Photographs and Diagrams / Introduction / Projects / 1. Wind / 2. Wood Heat Applications On the Farm / 3. Solar Applications / 4. Manure Handling and Waste Utilization / 5. Energy Efficient Cooling Methods / 6. Energy Saving In Field Operations / 7. Production and Use of Alternative Fuels / 8. Multi-Project Sites / Summary and Conclusions / …

Real Time Interactive Graphics Systems Identification, Youcef Hammada

Masters Theses

“This thesis describes the implementation of an identification procedure as a package of graphic programs. This package of graphic programs will allow the user to perform a least squares parameter estimation, a recursive least squares parameter estimation, and a maximum likelihood parameter estimation of a linear second-order transfer function model. This model describes in a linear form the dynamic response of an automobile in a field operating environment.

The model is to reasonably reproduce the physical behavior of an automobile through two of its dynamic variables. These are the yaw rate as output and wheel angle as input. The model …

Error Detection For Data Communication Systems, John Biancamano

Theses

A description of the problems encountered in the data communications field and the various solutions can be found in a number of diverse, and often theoretical sources. My intention in writing this thesis is to bring together, in a practical and understandable manner, the theory and the application of a method of error detection used extensively in data communication systems known as the Cyclic Redundancy Check (CRC).

To provide some background on the subject, a description of a data communication system is presented, and the possible sources of error are explored in some detail. Data transmission formats are described, and …

The Application Of Bond Graphs To Electrical Machinery And Power Engineering, K. Sirivadhna, Earl F. Richards, Max Darwin Anderson

Electrical and Computer Engineering Faculty Research & Creative Works

No abstract provided.

Estimation Of Ocean Wave Wavenumber And Propagation Direction From Limited Synthetic Aperture Radar Data., Gordon E. Carlson

Electrical and Computer Engineering Faculty Research & Creative Works

A method for estimating wavenumber and propagation direction for the dominant wave component in an ocean wave field from a few scans of synthetic aperture radar data is described and analyzed. The use of just a few radar scans rather than a complete image reduces data storage requirements significantly. The analysis shown uses actual synthetic aperture radar data and provides parameter tradeoffs and statistical performance results. While reasonable estimates of wavenumber and propagation direction are achieved in some cases, the estimates are not sufficiently consistent to be satisfactory over a wide range of cases. The primary problem is one of …

The Application Of Bond Graphs To Electrical Machinery And Power Engineering, K. Sirivadhna, Earl F. Richards, Max Darwin Anderson

Electrical and Computer Engineering Faculty Research & Creative Works

The bond graph technique, which has been related almost entirely to the field of mechanics, is a modeling procedure where emphasis is placed on the flow of power and energy in a system. Through specific digital simulation programs such as ENPORT IV and V and THTSIM the state space representation, associated output equations and system dynamic response are directly obtainable from the bond graphs. This approach has a great advantage where a complex system is composed of electrical, mechanical, thermal, hydraulic or pneumatic subsystems, such as would exist, for example; in a boiler, turbine, generator exciter system together with its …

Improved Wavenumber Resolution For Small Arrays, Richard E. Dubroff

Electrical and Computer Engineering Faculty Research & Creative Works

The Objective of the Method Described is to Compute the Fourier Transform of a Function of Space and Time with a Significant Improvement in the Resolution of Spatial Frequencies, particularly in the Case of Small Arrays for Which the Size of the Array is on the Order of One Wavelength (Or less). This Improvement is Initially Developed by Considering the Conversion of Spatial Frequency into Temporal Frequency through the Oscillatory Motion of a Single Receiver. a More Practical Scheme is Next Presented in Which the Oscillatory Motion is Created Synthetically by the Appropriate Sequential Sampling of Individual Elements in a …

Line-Adaptive Hybrid Coding Of Images, Tai On Tam, John A. Stuller

Electrical and Computer Engineering Faculty Research & Creative Works

This Paper Describes Novel Adaptation Strategy for Hybrid Transform/DPCM Image Coders. This Strategy Has Yielded a 2–8 DB Increase in Signal-To-Noise Ratio in the Transmission of a Head and Shoulders Image at Bit Rates of 1–4 Bits Per Pel and One-Dimensional Transform Block Sizes of 2–16. © 1983 IEEE

Electrical Engineering, C. J. Thomforde

UND Departmental Histories

This departmental history was written on the occasion of the UND Centennial in 1983.

Microcomputer Control Of A Model Robot System Using Programmable Pulse Width Modulation, Richard Eugene Wainwright

Masters Theses

"The hardware design of a model robot system for experimentation in microcomputer control is presented. A special interface board is designed to allow an Apple II Plus microcomputer to control a model robot system which consists of a three-jointed robot with an electromagnet end effector and a conveyor belt, with an optional vision system. A programmable pulse-width modulator is designed to drive the DC motors which operate the robot and conveyor belt. Improvements and additional uses for the model system are discussed"--Abstract, page ii.

Analysis Of The Isolated Induction Generator, L. Ouazenne, George Mcpherson

Electrical and Computer Engineering Faculty Research & Creative Works

No abstract provided.

Bibliography Of Power Systems Operator Training Resources Ieee Committee Report Prepared By The Pes Working Group On Operator Training (Wg78-4), Max Darwin Anderson

Electrical and Computer Engineering Faculty Research & Creative Works

This paper provides a current listing of training courses, programs, and resource materials for Power System Operator/ Dispatcher training. The training resources are subdivided into five (5) categories: I. Dispatcher training courses and facilities developed by the Suppliers/Manufacturers II. University Short Courses III. Conference Publications IV. Reference Books V. Correspondence Courses A brief description of the offerings of each of the Suppliers/ Manufacturers is included. Copyright © 1983 by The Institute of Electrical and Electronics Engineers, Inc.

Bibliography Of Power Systems Operator Training Resources, Max Darwin Anderson

Electrical and Computer Engineering Faculty Research & Creative Works

This paper attempts to provide a current listing of training courses, programs, and resource materials for Power System Operator/Dispatcher training. The training resources are subdivided into five (5) categories: I. Dispatcher training courses and facilities developed by the Suppliers/Manufacturers II. University Short Courses III. Conference Publications IV. Reference Books V. Correspondence Courses A brief description of the offerings of each of Suppliers/Manufacturers is included. Copyright © 1982 by The Institute of Electrical and Electronics Engineers, Inc.

The Performance Of Full Response Multi-H Modems In Practical Environments, Mark Alan Wickert

Doctoral Dissertations

The power and bandwidth efficiency of multi-h continuous- phase modulation (CPM) schemes in practical environments are considered. Specific impairments considered are transmitter filtering, amplitude limiting, and receiver symbol timing, phase error, and decision depth sensitivities. A coherent receiver model is employed which uses the Viterbi algorithm (VA) to perform maximum likelihood sequence estimation. For (2/4,3/4), ll (3/8,4/8) and (4/8,5/8) linear phase codes, a signal-to noise ratio (SNR) power gain of 1.85 dB, 1.9 dB, and 2.4 dB at a bit error rate (BER) of 10^-5 over differentially coded minimum-shift keyed (MSK) modulation are obtained, respectively. With transmitter filtering the …

Considerations In Developing And Utilizing Operator Training Simulators, T. E. Dyliacco, M. K. Enns, J. D. Schoeffler, J. J. Quada, D. L. Rosa, C. W. Jurkoshek, Max Darwin Anderson

Electrical and Computer Engineering Faculty Research & Creative Works

Effective electric system operation depends on strengthening the relationship between the system operator and the electrical system with its associated control system. This relationship can be developed through a training medium which increases the operator's knowledge of the behavior of the power system under various operating conditions and contingencies, and its response to control actions. An Operator Training Simulator (OTS), which simulates the static and dynamic responses of the operator's power system and his control system, can accomplish these training objectives. The concepts developed in this paper are based on the work of the project team through funding by the …

Model Studies Of Oxygen-Intercalated Graphite, Aldona M. Butkus, Cary Y. Yang, Y. W. Tsang, C. Y. Fong

Electrical and Computer Engineering

The possibility of intercalating oxygen to reduce the conductivity of graphite has been investigated by modified intermediate neglect of differential overlap 3 and tight-binding methods. The cluster calculations suggest that the most stable position for the oxygen atom is 1.25 A above a carbon-carbon bond. The tight-binding band calculation predicts the stage-I intercalated graphite to be a zero-indirect-gap semiconductor. Higher-stage intercalated graphite is expected to have a finite insulating gap whose value is governed by the carbon-oxygen interaction.

Subharmonic Generation By Resonant Three‐Wave Interaction Of Deep‐Water Capillary Waves, Partha P. Banerjee, Adrianus Korpel

Electrical and Computer Engineering Faculty Publications

Subharmonic generation has been observed during the propagation of deep‐water capillary waves. The observations are shown to be in agreement with the theory of degenerate resonant noncollinear three‐wave interaction in a nonlinear, dispersive medium.

Effects On Electrolytic Cells Of Magnetic Fields Applied To Single Electrodes, Craig Allen Cousins

Dissertations and Theses

The primary goal of this research was to investigate the effects associated with the application of magnetic fields to single electrodes.

Explicit Determination Of The Complex Refractive Index Of An Absorbing Medium From Reflectance Measurements At And Near Normal Incidence, R. M.A. Azzam

Electrical Engineering Faculty Publications

Measurement of reflectance at normal incidence R and its fractional change ΔR/R caused by a change of the angle of incidence from 0 to a small angle ϕ (ϕ≲ 20°) permits explicit determination of both the refractive index n and extinction coefficient k of an isotropic absorbing medium. The medium of incidence (ambient) is assumed to have a known refractive index (e.g., =1 for vacuum or air), and the incident light is either p or s linearly polarized.