Engineering Commons^™

Dynamics Of Interconnected Systems With Pulse Frequency Modulators, Halil Ozcan Gulcur

Dissertations

The objective of this dissertation is to study the dynamics of systems consisting of interconnections of an arbitrary number of complete-reset pulse frequency modulators (CRPFM's) and linear dynamical subsystems (in general, time-varying, lumped and/or distributed). CRPFM, which represents a generalization of several types of pulse frequency modulators (PFM's), consists of two basic components; a multi-input dynamic element, called the timing-filter (TF) and a threshold device (TD). Whenever the output of the TF reaches a given threshold value the TD generates an impulse and, at the same time, resets all the states of the TF to zero. This dissertation is devoted …

Gaussian Light Beams In Inhomogeneous Media, Lee W. Casperson

Electrical and Computer Engineering Faculty Publications and Presentations

Vector wave solutions are obtained for the propagation of beams of light in media having slow spatial variations of the gain, loss, or index of refraction. The formalism developed here is applicable to a wide range of problems, and an exa mple considered in detail is the propagation of off-axis beams in lenslike laser materials and optical waveguides. A procedure is also described for the diagnosis of localized dielectric inhomogeneities such as plasmas by means of Gaussian laser beams.

Correlation Of Drain Breakdown With Excess Noise And Other Surface-Related Phenomena In Enhancement Mosfets, Jerry J. Rij

Theses

An investigation of semiconductor surface-related phenomena has been undertaken to correlate 1/F noise with drain breakdown in P-channel enhancement MOSFET's. Increases in the intensity of drain current fluctuations at 10Hz and at 1KHz, particularly at the higher frequency, was observed following accelerated life-testing for threshold voltage drift. It was also concluded that mobile ions near the oxide-semiconductor interface produce a sharp increase in fast trapping centers. It was also found that 1/F noise intensity consistently peaked at the threshold of drain breakdown and that it steadily decreased with further increases in drain current. Of all the transistors tested, those with …

Non-Transposing Mute, Benjamin R. Gossick, Karl A. Schneider

Electrical and Computer Engineering Faculty Patents

A non-transposing mute having a metallic hemispherical resonator with a hollow acoustic filter attached thereto is provided for detachably fitting upon the rim of a brass musical instrument. A variety of tonal quality is available by choice of the particular filter selected by the musician.

Memory Utilization For A Dynamically Microprogrammed Computer, Paul D. Stigall

Electrical and Computer Engineering Faculty Research & Creative Works

A Particular, Dynamically Microprogrammed Computer (Proposed by Tucker and Flynn in Commun. of ACM, April 1971) is Considered with Respect to Main Memory and Micro-Memory Utilization. a Dependency is Shown between Memory Utilization and Utilization of the Arithmetic and Logic Unit.

Symmetry-Forbidden Resonant Raman Scattering In Cu2O, S. P. S. Porto, P. F. Williams

P. F. (Paul Frazer) Williams Publications

We have observed resonant Raman scattering from the two longitudinal branches of the Raman-forbidden F_{1u modes of Cu2O. The agreement between our measured scattering cross section as a function of excitation frequency and a calculated cross section which assumes an intraband Frohlich electron-phonon interaction is good. This represents a quantitative confirmation of the resonant-Raman-scattering theory proposed by Martin.}

An Historical Review Of Oil Spills Along The Maine Coast 1953-1973, Edward H. Shenton

Maine Collection

An Historical Review of Oil Spills Along the Maine Coast 1953-1973

by Edward H. Shenton

Prepared for The Maine State Planning Office, Coastal Planning Group and The Research Institute of the Gulf of Maine (TRIGOM), August, 1973.

TRIGOM Publication No. 3

Contents: Introduction / A Chronology of Significant Oil Spills / A Summary of Biological Impacts / Spill Statistics / Discussion of Results / Conclusions of the Study / Recommendations for Future Research / Appendices

Fast Neutron Effects On Time Delay Occuring In Gallium Arsenide Laser Diodes., James Owen Schroeder

Electrical and Computer Engineering ETDs

A study has been made on the effects of fast neutron irradiation on time delay occurring in diffused GaAs laser diodes operating at 77° K and 300° K. Measurements were performed at 300° K prior to irradiation and thence after successive exposure to neutron irradiation to a maximum of about 1.2 x 10^14 nvt (>10 KeV). At 77° K, measurements were limited to a pre-irradiation characterization and a characterization after the final irradiation. A double acceptor model is used to account for the observed changes in the delay characteristics as a result of both temperature changes and neutron irradiation. …

An Experimental Study Of Ultrahigh Fluence Oxygen Ion Implantation In Silicon, Charles Burton Fite

Electrical and Computer Engineering ETDs

An investigation was made to determine the feasibility of using ultrahigh fluences of implanted oxygen ions to create a usable oxide layer on silicon for device applications. Previous studies have indicated that SiO₂ can indeed be formed in this manner, but very little work has been reported on the electrical and structural nature of the resulting oxide-silicon interface. Six implants with fluences ranging from 1.25 x 10¹⁷ to 1 x 10¹⁸ (O₂)⁺ /cm² were performed into p-type silicon wafers. The implanted material was then studied to determine how the variables of anneal time, …

Generalized Feedback Shift Register Pseudorandom Number Algorithm, Theodore Gyle Lewis, W. H. Payne

Electrical and Computer Engineering Faculty Research & Creative Works

The generalized feedback shift register pseudorandom number algorithm has several advantages over all other pseudorandom number generators. These advantages are: (1) it produces multidimensional pseudorandom numbers; (2) it has an arbitrarily long period independent of the word size of the computer on which it is implemented; (3) it is faster than other pseudorandom number generators; (4) the "same" floating-point pseudorandom number sequence is obtained on any machine, that is, the high order mantissa bits of each pseudorandom number agree on all machines— examples are given for IBM 360, Sperry-Rand-Univac 1108, Control Data 6000, and Hewlett-Packard 2100 series computers; (5) it …

Adaptive, Differential Pulse-Code Modulation For Speech Processing, Peter Cummiskey

Dissertations

The objective of the research reported here is the design of efficient speech coders that can easily be implemented in integrated circuit hardware. Companding techniques like those introduced by M. R. Winkler, J. A. Greefkes, F. DeJager, A. Tomozawa and H. Kaneko were explored along with a large body of theory concerning the application of linear prediction to speech coding.

The best features of the speech signal to be measured and coded are the overall amplitude, the resonant frequencies and dampings of the vocal cavity and the fundamental frequency of the vocal cord oscillations. Adaptive quantization was used to track …

An Intensity-Dependent Filter, James M. Thorne, Thomas R. Loree, George Mccall

Faculty Publications

It is useful in optically driven Kerr-cell shutters and other laser applications to have intense pulses with extremely low light levels between pulses. We describe here a device that accomplishes this objective external to the laser cavity.

Digital Computer Solution Of Electromagnetic Transients In Large Power Systems, Bijan Navidbakhsh

Dissertations and Theses

This thesis is an introduction to the solution of electromagnetic transients by a combination of the Bergeran method of characteristics and the application of trapezoidal rule of integration.

Three test examples solved by digital computer illustrate the step by step solution and computer programming.

To compare this method with the Laplace transformation technique, a test problem solved by both methods and also digital computer is illustrated. In conclusion, the advantages and disadvantages of both methods are compared.

The Random Sequence Closing Control System, Henri Bernard Joyaux

Dissertations and Theses

This thesis describes a digital control system used by the Network Analog Group of the Bonneville Power Administration. This system, the Random Sequence Closing Control System, provides automatic control for a special purpose analog computer used in the study of switching surge over voltages on power transmission lines. This system, which uses pseudorandom data, has made it feasible to analyze switching surge phenomena on a statistical basis.

Resonant Raman Scattering From Iodine: Spectral Changes With Excitation Frequency, P. F. Williams, D. L. Rousseau

P. F. (Paul Frazer) Williams Publications

We have recorded high-resolution resonant Raman spectra of molecular iodine which show very pronounced systematic spectral band-shape variations with incident laser frequency. This frequency dependence and the presence of the multiple overtones in resonant Raman scattering from iodine may be explained by a theory in which the scattering intensity depends on Franck-Condon overlap integrals. We have obtained semiquantitative agreement between the observed spectra and spectra calculated from this theory.

Electrical Parameter Correlations For Radiation Hardness Assurance Of Operational Amplifiers, John L. Mullis

Electrical and Computer Engineering ETDs

In the manufacture of integrated circuits, a consider­able amount of attention is given to controlling fabrication processes. This is required if high production yield and consistent quality are to be obtained. In addition to moni­toring critical parameters which are influenced by variables in processing, the packaged circuits undergo a variety of tests to determine whether they meet the desired electrical and environmental quality specifications. The problem of quality assurance is accepted and treated as an essential part of the production cycle.

State Estimation In Discrete-Time Linear Systems With Quadratic Form Observers, James Parish Shipley Jr.

Electrical and Computer Engineering ETDs

The problem considered in this dissertation is that of estimating the state of a system with a linear plant equation but having a measurement function which is a quadratic form in the state. It is first demonstrated by constructive proof that the problem has a solution if the controls have large enough magnitude, and some requirements on the minimum size of the control are discussed.

Three algorithms for estimating the state are obtained, one using the technique of maximum likelihood, the other two utilizing a more general Bayesian approach. In addition, a first-order approximate conditional mean filter is included for …

Dosimetry For High Intensity, 2 Mev Radiation., Clifford Ledth Schroeder

Electrical and Computer Engineering ETDs

The purpose of this effort is to evaluate several types of dosimeters being used with the 2-MeV flash X-ray facilities at The University of New Mexico and the Air Force Weapons Laboratory (AFWL). The types include lithium fluoride and calcium fluoride thermaluminescent dosimeters (TLD's), thin foil calorimeters, p-i-n diodes, cobalt glass chips, and #25 purple Cinemoid. The evaluation includes a comparison of dose measurements, repeatability, and useful ranges. This report describes fundamental physical mechanisms by which photons and high energy electrons interact with matter, the physical mechanisms of different dosimeters, and techniques for using the dosimeters. The calcium fluoride TLD's …

Trajectories Describing The Evolution Of Polarized Light In Homogeneous Anisotropic Media And Liquid Crystals, Rasheed M.A. Azzam, N. M. Bashara, B. E. Merrill

Electrical Engineering Faculty Publications

Trajectories are given that describe the evolution of the ellipse of polarization in the complex plane for light propagating in a homogeneous anisotropic medium and along the helical axis of a cholesteric liquid crystal. For the general homogeneous anisotropic medium that exhibits combined birefringence and dichroism the trajectory is a spiral that converges to the low-absorption eigenpolarization. For pure birefringence the trajectory becomes a complete circle that encloses one eigenpolarization, whereas for pure dichroism the trajectory becomes an arc of a circle that ends at the low-absorption eigenstate. The case of a cholesteric (or twisted nematic) liquid crystal leads to …

The Effects Of Ionizing Radiation On Gallium Arsenide Phosphide Metal-Insulator-Semiconductor Structures, Gordon James Kuhlmann

Electrical and Computer Engineering ETDs

MIS capacitors were fabricated on n-type GaAs 0.5 p 0.5 using a thermally grown chromium-doped insulator and chromium gate electrode. The fabrication procedures which lead to stable devices are described. The nature of the composite insulator, as well as that of a disordered layer of GaAs 0.5 P 0.5 underneath the insulator are discussed and related to observed electrical characteristics.

Flatband voltages for the capacitors subsequent to device fabrication ranged from -2.5 to -5 volts, corresponding to surface charge densities of 3.1 x 10 11 cm-2 to 4.3 x 10 11 cm-2. Fast interface state densities at flatband varied from …

A Study Of The Dickey-Lincoln Hydroelectric Project And Its Impact On The Resources Of The Upper Saint John River Valley, Rosemary M. Manning, Sierra Club, New England Chapter

Dickey-Lincoln School Lakes Project

This report was under-taken primarily to evaluate the impact that the construction of the Dickey-Lincoln project would have upon the resources of the Upper St. John River, and to examine the assertion that the Dickey-Lincoln project constitutes a wise use of the public's environmental and economic resources. Since the case that has been made for the construction of the Dickey-Lincoln project rest primarily on the justification of the project in economic terms, this aspect of the project proposal will be intensively explored.

Loci Of Invariant-Azimuth And Invariant-Ellipticity Polarization States Of An Optical System, Rasheed M.A. Azzam, N. M. Bashara

Electrical Engineering Faculty Publications

The loci of polarization states for which either the ellipticity alone or the azimuth alone remains invariant upon passing through an optical system are introduced. The cartesian equations of these two loci are derived in the complex plane in which the polarization states are represented. The equations are quartic and are conveniently expressed in terms of the elements of the Jones. matrix of the optical system. As an exple the loci are determined for a system composed of a π/4 rotator followed by a quarter-wave retarder.

Nutation Control During Precession Of A Spin-Stabilized Spacecraft, Richard James Donner

Masters Theses

"The effects of precession thrust pulses and energy dissipation upon nutation of a spin-stabilized spacecraft are studied. Methods for controlling nutation during a precession maneuver are proposed and examined. In particular, a precession modulation control law is developed which uses precession thrust pulses to control nutation. Digital simulations show that precession control with separate nutation control is the fastest precessing system; however, the precession modulation method is only fractionally slower while not requiring a separate nutation control system"--Abstract, page ii.

On The Method Of Stationary Phase, Byungkyu Park

Electrical and Computer Engineering Faculty Research & Creative Works

The method of stationary phase (MSP), which is an asymptotic method of integration, nevertheless yields general (nonasymptotic) results when applied to certain integrals involving the spherical function. In such cases one may drop the requirement of far-field or high frequency from the results. Copyright © 1973 by The Institute of Electrical and Electronics Engineers. Inc.

Performance Degradation Due To Specular Multipath Intersymbol Interference, G. H. Smith, David R. Cunningham, Rodger E. Ziemer

Electrical and Computer Engineering Faculty Research & Creative Works

Plots of performance degradation are used to compare the effects of fading and intersymbol interference in a two-component specular multipath digital communications channel. Similar plots are then used to compare two practical receivers designed to combat the interference. Degradation plots are shown to allow easy identification of each receiver's range of usefulness, as well as identification of variance bounds demanded of channel parameter estimates which the receivers require. Copyright © 1973 by The Institute of Electrical and Electronics Engineers, Inc.

Analysis And Design For Semi-Automatic And Automatic Control Of Vehicles By Permanent Magnets, Hari K. Mehta

Masters Theses

"The analysis and design carried out in this study relates to automatic or semi-automatic lateral control of a vehicle. This is one of the three essential subsystems needed for a complete automatic control system. The other two subsystems provide longitudinal control, and intersection or lane-changing control.

The system studied employs a series of permanent magnets which have been embedded vertically in the road and spaced at an interval to be used for position reference, leading to discontinuous error signal. This system has been analyzed by classical Z-transform analysis and control models have been developed for two kinds of controls. First, …

A Multivariable Sampled-Data Model Of An Automobile Driver, Jose A. Bermudez

Masters Theses

"In this thesis, a multivariable system model of driver performance in the basic driving tasks is presented. The driver model described acts as a serial-process, priority-accessed, time-sharing computer. This model processes the input or output task which currently possesses the highest priority. Input tasks are represented by continuous signals sampled intermittently according to priority laws. Output tasks are modeled as simple analog processes operating on the last few intermittently generated output controls. An individual priority rule is constructed for each input and output task.

The performance of the driver in the lateral control task involves a feedforward pattern which is …

A Thin Film Evaporator Rate Controller, Daniel Robert Kasterlein

Masters Theses

"A circuit is described which is used to control the evaporation rate of material from a resistance heated boat or electron beam evaporator. The rate controller is used in conjunction with a quartz crystal thickness monitor in a vacuum evaporator"--Abstract, page ii.

A Study Of Rf Induction Heating And Float Zone Refining Of Silicon, John Allen Reynolds

Masters Theses

"Float zone refining using simultaneous RF induction heating and electromagnetic levitation has proven to be the best technique for producing high purity silicon for the semiconductor industry.

A study of the power requirements for floating molten zones, of load to source impedance matching, and of considerations for RF heating coil design was conducted to determine possible methods of improving the technique. It is shown that the power requirements are within reason, that impedance matching can be improved by varying network parameters, and that certain vital items must be assured in the design of different RF heating coils.

It is believed …

Inertial Navigation Performance Improvement Realized By The Technique Of Interrupted Alignment, Ralph E. Herndon

Masters Theses

"Present on-aircraft ground alignment gyro bias methods can basically be categorized as (1) periodic maintenance performed by the ground crew, (2) pre-flight calibration requiring a two-position gyro compass alignment or (3) optimal filter estimation of the north gyro bias error.

This thesis discussion presents an interrupted alignment method that allows adequate level axes gyro bias correction without the restrictions associated with a conventional two-position gyrocompass alignment (i.e., a minimum time for bias calibration on a steady aircraft). The interrupted alignment technique allows the pilot to select the navigate mode at any point during gyrocompass and reselect the align mode at …