Engineering Commons^™

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 …

Automated Arrhythmia Detection In The Exercise Electrocardiogram, Gregory Ciurpita

Theses

A self-adapting, non-real time method for detecting arrhythmias in single channel Exercise ECG is described. Linear and non-linear digital filtering techniques are used to remove additive noise. A time-varying threshold technique is used to detect R-waves based on amplitude. Feature extraction and matched filter methods are used to classify QRS-waves into existing types, or to create new types. The program works on digitized data from floppy disk and plots all data along with classification results on ReGis graphics terminal or printer. This work will continue so that the system will be capable of processing three-channel ECG in real-time.

Digitally Implemented Klapper-Kratt Fm Detector Using The Intel-292o Digital Signal Processor, Chang-Hwan Park

Theses

This thesis describes and analyses a digitally implemented FM detector, which is a new member of the family of FM detectors introduced by Drs. Klapper and Kratt.

The properties of the new detector are low delay, excellent sensitivity, extreme linearity, and compatibility of components with integrated circuit technology.

A working model is implemented by adapting FIR digital s signal processing methods, and is realized using the Single-Chip Digital Signal Processor Intel-2920 which is comprised of micro-processor, scratch-pad data RAMs, program store EPROMs, A/D and D/A conversion circuitry, and I/O circuitry.

The performance of the working model shows very good linearity …

A Parameter Identification System For The Human Electroretinogram, Yu-Huai Hsiao

Theses

The human Electroretinogram (ERG) is obtained in a clinical test to detect physiological abnormalities in the eye. A mathematical model of the ERG has been developed, as well as a system to identify its parameters. The system utilizes several computers. The data acquisition and initial processing is done on a previously developed system at the Eye Institute of New Jersey and the University of Medicine and Dentistry of New Jersey, which has been modified to provide the facility for further processing. Software was developed to use a MINC-11/23 computer at New Jersey Institute of Technology to transfer data between the …

Pressure Distributions In Microvascular Network, David Moshenberg

Theses

The objective of this study was to find a practical way of estimating the pressure distribution in a network of microvascular vessels. The pressure distribution was evaluated twice, namely before vasodilations or vasoconstrictions and after the network of vessels reached a new steady state with respect to pressure and flow. Along with determining the pressure distribtuion, the simulation also calculated an effective blood viscosity coefficient for the network.

Poiseuille's equation and the axial component of the equation of motion were used to evaluate the steady state pressure and velocity distributions in each vessel. The continuity equation (conservation of mass) was …

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 …

16-Channel Signal Analyzer For Electroencephalograms, Junnyih Chiang

Theses

An instrument has been designed to analyze 16 channels of EEG of a squirrel monkey by using several interface boards controlled by an Apple II computer. This instrumentation system is capable of performing these experiments in an automated manner. It stores the data generated on to a floppy disk, with software control and results may be printed out together with related graphs. Because of the limitation of the floppy disk capacity, we had only developed two versions:

(1) To average the EEG signal up to 8 times for all 16 channels, because a lot of memory is needed to save …

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 …

Digital Fm-Demodulation Using Digital Signal Processing Techniques, Peter Wagner

Theses

This thesis presents the results of research in the area of digital demodulation of FM signals. The first part of the thesis describes the performance of digital Hilbert-transformers and Differentiators that are optimized in a determined bandwidth. These digital filters are used to build a digital Klapper-Kratt detector. According to this procedure, the coefficients of the digital Klapper-Kratt detectors up to the filter length N=25 are calculated and the resulting discriminator ripple computed and evaluated. One suggested algorithm gives the opportunity to balance the detector at a certain center-frequency. The major part of this thesis describes a new approach towards …

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 …

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 …

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.

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 …

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.

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.

Stability Analysis Of Fixed-Point Digital Filters Using Computer Generated Lyapunov Functions- Part I: Direct Form And Coupled Form Filters, A. Michel, Kelvin T. Erickson

Electrical and Computer Engineering Faculty Research & Creative Works

We demonstrate the applicability of the constructive stability algorithm of Brayton and Tong in the stability analysis of fixed-point digital filters. In the present paper, we consider direct form and coupled form filters while in a companion paper we treat wave digital filters and lattice filters. We compare our results with existing ones which deal with either the global asymptotic stability of digital filters or with existence (resp., nonexistence) of limit cycles in digital filters. Several of the present results are new while some of the present results constitute improvements over existing results. In a few cases, the present results …

Stability Analysis Of Fixed-Point Digital Filters Using Computer Generated Lyapunov Functions- Part Ii: Wave Digital Filters And Lattice Digital Filters, A. Michel, Kelvin T. Erickson

Electrical and Computer Engineering Faculty Research & Creative Works

In a companion paper [4], we utilize the constructive stability algorithm of Brayton and Tong in the stability analysis of fixed-point digital filters which are in the direct form and in the coupled form. We continue this work in the present paper by considering wave digital filters and lattice digital filters. We believe that the results of the present paper and its companion paper demonstrate that the constructive algorithm constitutes an effective and general approach in the qualitative analysis of fixed-pointed digital filters.

Growth Of Tungsten Selenide Films Through Pyrolytic Conversion And Anodic Electrooxidation Of Ammonium Selenotungstate ((Nh4)2wse4), R. D. Engelken, T. (Thomas) P. Van Doren, Jack L. Boone, A. K. Berry, A. Shahnazary

Electrical and Computer Engineering Faculty Research & Creative Works

WxSey thin films have been prepared by the spray pyrolysis and anodic electrodeposition of solutions of ammonium selenotungstate, (NH4)2WSe4, with y/x usually between two and three for the sprayed films and y x>>1 for the electrodeposited films. The sprayed films indicated regions of crystalline WSe2 and have optical absorbance spectra consistent with a mixture of WSe2, WSe3, and selenium. The electrodeposited films are totally amorphous, highly photoconductive, and have optical absorbance spectra typical of amorphous or vitreous selenium. The sprayed films transform into WO3 at temperatures greater than 350°C in the presence of oxygen wile the electrode-posited films tend …

Microcomputer Mrp In Three Months: Photon Kinetics, Wayne W. Wakeland

Complex Systems Faculty Publications and Presentations

Information about the company Photon Kinetics, a small, privately-held manufacturer of fiber optics test equipment, located in Beaverton, Oregon.

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.

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.

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 …

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 …