Digital Commons Network^™

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, …

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.

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.

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) …

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.

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 …

Electrical Engineering, C. J. Thomforde

UND Departmental Histories

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

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 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 …

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 …

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 …

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

Electrical and Computer Engineering Faculty Research & Creative Works

No abstract provided.

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 …

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.

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.

Coherence Effects In Synchronously Pumped Mode‐Locked Dye Lasers, Lee W. Casperson

Electrical and Computer Engineering Faculty Publications and Presentations

A formalism is developed for describing the evolution of picosecond mode‐locked pulses in synchronously pumped dye lasers. The finite phase memory of the molecular wave functions is included, and it is found that the resultant coherence effects can be dominant for operation close to exact synchrony. Considerations of the isotropic molecular orientational distribution and the finite vibrational relaxation times are also essential in obtaining quantitative agreement with experimental results.

Polarization-Preserving Single-Layer-Coated Beam Displacers And Axicons, R. M.A. Azzam, M. Emdadur Rahman Khan

Electrical Engineering Faculty Publications

A design procedure is described to determine the thicknesses of single-layer coatings of a given dielectric on a given metallic substrate so that any input polarization of light is preserved after two reflections at the same angle of incidence from a parallel-mirror beam displacer or an axicon. This is achieved by equalizing the net complex p and s reflection coefficients (also called the radial and azimuthal eigenvalues of an axicon) after two reflections. The net polarization-independent reflectance (insertion loss) of the device is computed and found to exceed the net minimum parallel reflectance of the uncoated device for incidence above …

Scheme To Polarization-Correct A Waxicon, R. M.A. Azzam

Electrical Engineering Faculty Publications

No abstract provided.

Stationary Property Of Normal-Incidence Reflection From Isotropic Surfaces, R. M.A. Azzam

Electrical Engineering Faculty Publications

The complex reflection coefficients for the parallel (p) and perpendicular (s) polarizations of light that are normally incident upon an isotropic surface are proved to be stationary with respect to small changes of the angle of incidence in the neighborhood of zero. This is true not only for a single interface between isotropic media but also for any one-dimensionally inhomogeneous or multilayer reflecting structure that is stratified in the direction of the surface normal. For incident light of certain intensity, phase, and polarization, the intensity, phase, and polarization of the reflected light all remain stationary with …

Remote Attitude Measurement Techniques, Frank John Elmer

Dissertations

A method has been developed for solving practical problems which can be expressed in terms of physical geometry. These problems often involve combining directional information observed by remotely located sensors reported in their own respective local coordinate systems. To transform this information into a common coordinate system, the attitude of the sensors must be measured with respect to this common coordinate system.

Physical geometry is a generalization of mathematical -geometry where objects define the endpoints of figures composed of ensembles of lines. A probabilistic approach has been taken which is based on the fundamental assumption that the objects can be …

Study Of Compositional Changes (Altered Layer) In (Hg,Cd)Te Targets Sputtered With Hg Vapor, Robert Granville Bourne

Theses

Six mercury cadmium telluride targets (5.74 cm diameter) with six polycrystalline (Hg_0.8 Cd_0.2 )Te ingots (1 x 3 x 0.7 cm ± 20%) epoxied on them, were r.f. sputtered in an MRC-8800 triode system for 1, 2, 3, and 5 minutes. The six sputtering runs were made with 3 different Hg pressures of 1.0, 1.25, and 1.6μm while the uniform target power density was kept constant at 7.7W/cm². After sputtering a target, Br₂ +CH₃OH was used to chemically etch the sputtered ingots to different depths. The surface composition of the etched ingots was …

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 …

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.

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 …

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 …

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.