Digital Commons Network^™

Quantification Of Indian Rights: Problems Of Proof, Harry R. Sachse

The Federal Impact on State Water Rights (Summer Conference, June 11-13)

32 pages.

Spontaneous Coherent Pulsations In Ring-Laser Oscillators: Stability Criteria, Lee W. Casperson

Electrical and Computer Engineering Faculty Publications and Presentations

The stability criteria implied by a simplified semiclassical laser model are considered in detail. It is found that two types of criteria must be distinguished. The first concerns the smallest pump rate for which infinitesimal perturbations of the steady-state solution will increase with time, and the second concerns the smallest pump rate for which large amplitude modulations will not damp away.

The Effect Of A Higher Order Pole On The Optimum Design Of Minimum Threshold Phase Locked Detectors, Bernard Zivotofsky

Dissertations

The phase lockedloop is widely used as an FM demodulator known as a phaselocked detector (PLD). It is particularly useful in the detection of weak signals because lower threshold is possible with a PLD than with a conventional limiter discriminator. An enhanced version PLD known as an extended range phaselocked detector (ERPLD) is capable of further threshold reduction. The most popular PLD is a second order type I system employing a loop filter having one real pole and one real zero.

One implementation of an ERPLD calls for the addition of a differentiator to the standard loop filter which replaces …

A Pitch Based Processor For The Analysis Of Steady State Laryngeal Modes, Tzyy-Jenq Lou

Theses

A data acquisition and analysis stem for use in the study of laryngeal dynamics has been built and tested. The special feature of the system is the computer controlled digitizing rate and coordinated subject pitch prompting. Tokens of steady state laryngeal vibration are obtained from an electroglottograph when the subject intones a series of computer prompted pitchs in a musically scalar sequence. The digital samples of this data are captured by the system at a basic rate of 200 samples per laryngeal cycle. This procedure enables the system to perform a modal analysis of laryngeal function, not unlike the analysis …

Microcomputer Controlled Continuous Activity Monitor For Small Caged Animals, Yogesh Parekh

Theses

The task of this instrumentation system is to measure the activity of rats in a controlled experiment. The system is designed to work in conjunction with the system for studies of metabolic rates in rats. The interface circuits take the picture from a video (vidicon) camera into the computer. Once the picture frame is taken into the high resolution graphics screen memory area, the computer uses this data to detect the activity. The movements of the rat are detected by comparing the number of pixels changed between two consecutive picture frames. The area covered by the rat determines the standing …

Computerized Instrumentation System For Indirect Measurement Of Metabolic Changes In Rats, Holger Tebbje

Theses

This work describes the further development of a system for the measurement of the energy expenditure of rats. Based on the concept of indirect calorimetry the respiratory exchange is monitored in a controlled experiment. Rats are held in cages through which air is drawn and analyzed. Transducers and sensors, interfaced to the computer, are measuring the composition and the physical parameters of the gas entering and leaving the chambers. The data recieved is processed, displayed on a screen, printed and stored for later analysis.

The accuracy and repeatability of the system improved by measuring additional parameters like barometric pressure and …

An Examination Of The Power Spectral Density Function, James Edward Coleman

Theses

The power spectral density (PSD) function is a characterization of an (ideal) signal or set of signals. It is usually associated with a stationary random process, but it need not be. In fact, to study its properties it is desirable to divorce the power PSD from any extraneous structure that may conceal its properties. Specifically, it is desirable to study Sτ(f) = | Xτ(f)|²/2T and determine how it approximates the power spectrum of a power signal S (f) = τ[R(τ)].

It is shown that it cannot be concluded (contrary to what some of the literature has reported) that …

Reliability Problems And Failure Mechanisms Of Solid Tantalum Capacitors, Ghanshyam B. Nakrani

Theses

Today, reliability is acknowledged as an important item in design and the operation of the electronic systems.

This thesis provides some theory, and experiments are instituted to evaluate the reliability for SOLID TANTALUM CAPACITORS made by different manufacturers. The experimental life test work was done at high temperature of 9S 2°C and high humidity of 95 ± 3% on transfer molded tantalum capacitors.

Literature study concentrates on the reliability in solid tantalum capacitors developed between 1961 and 1984.

Several failure mechanisms with figures are illustrated to point out how higher reliability of solid tantalum capacitors may be developed.

The bibliography …

Determining Process Latitude With Electrically Measurable Test Structures, Jonathan Littlehale

Theses

Collection of linewidth data is an important part of photoresist characterization. Linewidth data are usually collected by optical measurements or scanning electron microscopy. Both of these techniques are tedious and time-consuming. In this work, electrically measurable test structures are used to collect linewidth data. These structures use a measured sheet resistance, a known length of conducting material, and the measured resistance of the structure to determine the linewidth. The benefits of using these structures include completely automated data collection and the ability to collect statistically significant amounts of data. This allows the use of existing statistical analysis software to analyze …

Constraint On The Optical Constants Of A Film-Substrate System For Operation As An External-Reflection Retarder At A Given Angle Of Incidence, R. M.A. Azzam, Bruce E. Perilloux

Electrical Engineering Faculty Publications

Given a transparent film of refractive index n₁ on an absorbing substrate of complex refractive indexn₂-jk₂, we examine the constraint on n₁, n₂, and k₂ such that the film-substrate system acts as an external-reflection retarder of specified retardance Δ at a specified angle of incidence φ. The constraint, which takes the form ƒ(n₁,n₂,k₂;φ,Δ) = 0, is portrayed graphically by equi-n₁ contours in the n₂,k₂ plane at φ = 45, 70° and for Δ …

A New Design Concept For Field Distortion Trigger Spark Gaps, G. Schaefer, B. Pashale, P. F. Williams, K. H. Schoenbach, H. Krompholz

P. F. (Paul Frazer) Williams Publications

A common field distortion triggered spark gap utilizing geometric field enhancement at sharp edges usually operates in a cascade mode via the trigger electrode. A new trigger concept is proposed allowing strong field enhancement and direct breakdown between the two main electrodes. A test setup was designed to prove the feasibility of this concept. Experimental results on delay and jitter depending on percent breakdown voltage are presented. Best results achieved are a delay of 9 ns and a jitter of 2 ns at a self-breakdown voltage of 15 kV.

Test Derivation For Cmos Iterative Logic Arrays, Ravi Sharma

Electrical & Computer Engineering Theses & Dissertations

Testability criteria for stuck-open (s-op) faults in one-dimensional unilateral iterative logic arrays (ILA) of CMOS combinational cells are considered in this thesis. A functional fault model to represents-op faults i~ an ILA cell is given. The procedure to detect as-op fault needs a pair of test vectors. The first is used to set up the initial conditions required to test the fault and the second is the test which distinguishes between the good and the bad circuit. Based on this approach necessary and sufficient conditions are given for the testability of as-op fault in a CMOS ILA cell. These conditions …

Explicit Equations For The Polarizing Angles Of A High-Reflectance Substrate Coated By A Transparent Thin Film, R. M.A. Azzam

Electrical Engineering Faculty Publications

Simple explicit equations are derived that determine the angles of incidence at which the parallel and perpendicular polarization components of light are extinguished on reflection from a transparent film coating a high-reflectance (metallic) substrate. The polarizing angles obtained from our approximate expressions are in excellent agreement with those determined by iterative numerical solution of the exact nonlinear equations that govern such angles. For the approximation to be valid, the intensity reflectance of the film-substrate interface, evaluated at the critical angle of the film-ambient interface, must exceed 0.5.

Antireflecting And Polarizing Transparent Bilayer Coatings On Absorbing Substrates At Oblique Incidence, R. M.A. Azzam, Karim Javily

Electrical Engineering Faculty Publications

The condition of zero reflection of p- and s-polarized light by a transparent bilayer on an absorbing substrate is derived in the form |g_ν(ø,N_i)| ≤ 1, where g_ν is a function of the angle of incidence ø, the refractive indices N_i(i = 0,1,2,3) of the system, and the polarization state ν (= p or s). As an application, the air-Si₃N₄-SiO₂-Si system is considered at two laser wavelengths λ = 6328 and 3250 Å. The thicknesses of the two films of the bilayer and the …

Single-Layer Antireflection Coatings On Absorbing Substrates For The Parallel And Perpendicular Polarizations At Oblique Incidence, R. M.A. Azzam

Electrical Engineering Faculty Publications

Explicit equations are derived that determine the refractive index of a single layer that suppresses the reflection of p- or s-polarized light from the planar interface between a transparent and an absorbing medium at any given angle of incidence. The required layer thickness and the system reflectance for the orthogonal unextinguished polarization also follow explicitly. This generalizes earlier work that was limited to normal incidence or to oblique incidence at dielectric—dielectric interfaces. Specific examples are given of p- and s-antireflection layers on Si and Al substrates at λ = 6328 Å at various angles of incidence.

Numerical Simulation Of Streamer Propagation In Nitrogen At Atmospheric Pressure, S. K. Dhali, P. F. Williams

P. F. (Paul Frazer) Williams Publications

Results of the application of flux-corrected transport techniques to a two-dimensional numerical simulation of streamer propagation are presented. Characteristics such as diameter, velocity, shape, and density gradient of the head, and ionization in the body of the propagating streamer are determined. These results provide new insight into streamer propagation.

Extinction Of The P And S Polarizations Of A Wave On Reflection At The Same Angle From A Transparent Film On An Absorbing Substrate: Applications To Parallel-Mirror Crossed Polarizers And A Novel Integrated Polarimeter, R. M.A. Azzam

Electrical Engineering Faculty Publications

The p- and s-polarized components of light can be suppressed on reflection at the same angle of incidence from an absorbing substrate coated by a transparent thin film if the wave is refracted in the film at 45° and the constraint Re[(ε₂ - α)/(l -α)]^1/2 = α + | ε₂ - α| is satisfied, where 2α and ε₂ are the ratios of dielectric constants of the film and substrate, respectively, to that of the ambient. For high-reflectance metal substrates (|ε₂| » 1), α≈ 1, the ratio of film to ambient refractive index …

Failure Rates And Leakage Current Increase In Tantalum Capacitors Of Different Manufacturers, Joseph G. Grant

Theses

This study has determined the effect of high humidity and temperature on solid tantalum capacitors, from five different sources.

The reasons for using capacitors from five different prestigious sources is to first determine how the parameters change with the different manufacturing techniques used by the different sources. Secondly to rank the different sources according to reliability. The parameters that were measured before and after the "1000 hour" high temperature and humidity test were, capacitance, leakage current, and equivalent series resistance. All the capacitors showed significant increase in leakage current after the test, but there were wide variations in catastrophic failure …

Study Of Mo, Au, And Ni Implanted Molybdenum Laser Mirrors By Spectroscopic Ellipsometry, Paul G. Snyder, George H. Bu-Abbud, Jae Oh, John A. Woollam, David Poker, D. E. Aspnes, David Ingram, Peter Pronko

Department of Electrical and Computer Engineering: Faculty Publications

The implantation of 150 kev molybdenum ions into polished molybdenum laser mirrors is found to increase the complex dielectric constant in the visible spectrum. Analysis using the Bruggeman effective medium approximation demonstrates that the increase is due to surface smoothing and that the surface is made nearly atomically smooth by a fluence of 5 x 10¹⁵ /cm². Implantation of Au at 1Mev caused considerable microscopic roughening, as well as a change in the bulk optical properties. 3 MeV Ni ion implantation caused only a slight surface roughening. A thin dielectric film (probably a hydrocarbon) is found to …

Phase Statistics For A Lightwave Traveling Through Turbulent Media, Donald J. Link

Retrospective Theses and Dissertations

A probability density function is developed for the phase of light that is the result of adding a signal to noise with K-distributed amplitude and uniform phase. The probability density function of the phase associated with the I-K distribution is also developed. In the process of deriving the probability density function of the phase much I as learned about the relationships between different probability density functions. Three different methods of deriving homodyned K statistics are shown to be equivalent. Two different methods of deriving I-K statistics are shown to be equivalent. Theoretical moments of the homodyned K distribution are compared …

A Study Of Shadow Contrast For A Grating, Steve Eugene Watkins

Masters Theses

"A theoretical and experimental investigation of the causes of the reduction of the contrast in the shadow of a grating has been made. The variation of the shadow contrast is shown to be different for the two causes--diffraction and divergence. The conditions which determine the dominant effect are presented. Also, the contrast pattern due to diffraction is shown to have a squared scaling law while the divergence pattern is shown to scale linearly. This understanding of the shadow contrast increases the versatility and usefulness of the shadow moire technique, an optical method for determining the topography of surfaces"--Abstract, page ii.

An Evaluation Of Magnetic Field Shielding And Cross Talk For Various Cable Configurations, Amir Hossein Nafar

Masters Theses

"The effect of shield grounding on magnetic field coupling in coaxial and twisted pair cables, was studied for various positions of the ground connection at 50 KHz. For the case of only one end of shield grounded the attenuation was about 60 dB. Furthermore, the effect of frequency from 50-500 KHz was considered on three cases. Thus it was concluded that attenuation increases as frequency increases. A combined experimental and analytical investigation was also conducted to characterize the mechanism of cross talk between wires of ribbon cable and traces on printed circuit boards. Inductive and capacitive coupling were studied in …

Bistabiity By Induced Waveguiding In Coupled Semiconductor Lasers, Daniel Heffernan, J. Mcinerney, L. Reekie, D. Bradley

Articles

Recently, McInerney, Reekie, and Bradley observed bistability in twin diode GaAs/GaAlAs injection lasers in an external cavity when both diodes were above threshold. We show that this bistability may be explained by a form of self-focusing which is produced by induced waveguiding in the wide stripe lasers. A detailed analysis is performed on a standard model of these diodes in an external cavity. We have found very good agreement between theory and experiment.

Spontaneous Coherent Pulsations In Ring-Laser Oscillators, Lee W. Casperson

Electrical and Computer Engineering Faculty Publications and Presentations

Complex spontaneous-pulsation phenomena have been reported in xenon lasers operating at 3.51-μm wavelength, and a theoretical explanation for these effects has been given. However, the published models contain various simplifications and have so far yielded only qualitative agreement with xenon-laser experiments. Reported here is a more rigorous analytical model, which for the first time provides quantitative agreement with experimental observations. This model should also find direct application in interpreting or predicting the behavior of other spontaneously pulsing laser systems.

Fourier Transforms Over Warped Domains., Richard E. Dubroff

Electrical and Computer Engineering Faculty Research & Creative Works

The Author Shows that There May Be an Advantage to Computing Fourier Transforms Over Warped Domains. an Example of Such an Improvement is Provided. It is Also Shown How the Fourier Transform May Be Evaluated from Data Observed over a Warped Domain.

Modeling And System Identification Of Residential Air Conditioning Load, Anil Pahwa, Charles W. Brice

Faculty Publications

A fairly detailed physically-based model of the residential air condit$ oning system is presented. It has been shown that the paramstors of tho model can be identified by making a sequenco of measuremonts of on/off cycles of the air conditioner and the onvironment variables. A scheme to determine aggregate demand of the air conditionors using duty factors is presented. The effect on energy consumption and poak duty fa9tor of change in model parameters is determined. Also, the effect of reduction in the supply voltage is studied using this model and it has been found that the steady state air conditioning …

Electric And Magnetic Field Induction On Parallel Transmission Lines, Robert Joseph Schnell

Masters Theses

"The theory behind electric and magnetic field induction is developed. The theory is then applied to the calculations of induced voltages and currents on a de-energized three phase transmission line paralleling an energized three phase transmission line. The effect of shield wires on the induction phenomena is explained. Interactive computer programs for both electric and magnetic field induction are presented and instructions given for their use. Both programs are stored on disks and are for use on an IBM (or compatible) personal computer. Example problems are posed and solved"--Abstract, page ii.

Negative Corona Current Characteristics Of An Electric Wind System, Aviti Kadete

Tanzania Journal of Engineering and Technology (TJET)

The corona current characteristics of an electric wind system are investigated. First a brief summary of the negative point to plate corona mechanism and characteristics are presented. Then empirical equations for corona currents of an electric wind system are derived. Current waveform characteristics are also discussed. The effects of placing parallel rods in between a point-plate electrode gap to the corona currents are highlighted.

Solvable Hill Equation, Lee W. Casperson

Electrical and Computer Engineering Faculty Publications and Presentations

A second-order linear differential equation with continuous periodic coefficients is solved exactly in terms of elementary functions. Equations of this type arise commonly in several areas of physics, and the solutions may find practical applications. As an illustration, the results are applied to the problem of an electron in a one-dimensional periodic potential.

Multiple Determination Of The Optical Constants Of Thin-Film Coating Materials, D. P. Arndt, R. M.A. Azzam, J. M. Bennett, J. P. Borgogno, C. K. Carniglia, W. E. Case, J. A. Dobrowolski, U. J. Gibson, T. Tuttle Hart, F. C. Ho, V. A. Hodgkin, W. P. Klapp, H. A. Macleod, E. Pelletier, M. K. Purvis, D. M. Quinn, D. H. Strome, R. Swenson, P. A. Temple, T. F. Thonn

Electrical Engineering Faculty Publications

The seven participating laboratories received films of two different thicknesses of Sc₂O₃ and Rh. All samples of each material were prepared in a single deposition run. Brief descriptions are given of the various methods used for determination of the optical constants of these coating materials. The measurement data are presented, and the results are compared. The mean of the variances of the Sc₂O₃refractive-index determinations in the 0.40–0.75-nm spectral region was 0.03. The corresponding variances for the refractive index and absorption coefficient of Rh were 0.35 and 0.26, respectively.