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Surface Self-Diffusion On Nickel (111) By Radioactive Tracers, James Ronald Wolfe Jan 1968

Surface Self-Diffusion On Nickel (111) By Radioactive Tracers, James Ronald Wolfe

Doctoral Dissertations

"Surface self-diffusion coefficients have been measured by a radioactive tracer method over the temperature range 614⁰ to 840⁰C on nickel (111) surfaces characterized by LEED. Previously unrecognized tracer evaporation during surface diffusion resulted in restricted spreading of the tracer at higher temperatures. A theoretical treatment of the tracer evaporation phenomenon is presented and subsequently used in the analysis of the data. The temperature dependence of the surface self-diffusion coefficient (Ds) for nickel (111) can be represented, over the experimental temperature range, by a single Arrhenius type relationship...Arguments are presented to justify an adatom surface diffusion mechanism which is …

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The Effect Of Polymer Structure On Drag Reduction In Nonpolar Solvents, Gin Chain Liaw Jan 1968

The Effect Of Polymer Structure On Drag Reduction In Nonpolar Solvents, Gin Chain Liaw

Doctoral Dissertations

"The effects of polymer chain flexibility, molecular weight and entanglement capacity, and of polymer solution concentration on drag reduction in nonpolar solvents were studied in this investigation. Three samples of polydimethyl siloxane in toluene, five samples of polyethylene oxide in benzene, two samples of cis-polyisoprene in toluene, trans-polyisoprene in toluene, cis-polybutadiene in toluene, ethyl cellulose in toluene and a copolymer of epichlorohydrin and polyethylene oxide in toluene were studied. Molecular weights of all polymers were estimated from intrinsic viscosity, except for the molecular weight of the copolymer which was given by the manufacturer. Turbulent and laminar flow pressure drop data …

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The Damage Assessment Of Thermally Shocked High Density, High Purity Aluminum Oxide, John H. Ainsworth Jan 1968

The Damage Assessment Of Thermally Shocked High Density, High Purity Aluminum Oxide, John H. Ainsworth

Doctoral Dissertations

"The traditional approach to thermal shock testing in brittle materials has been to determine the temperature difference required to nucleate cracks in these materials. Recent work has indicated that the degree of damage after crack nucleation should be an additional consideration. The degree of damage resulting from cooling thermal shocks has been the primary consideration of the present work. Test specimens of two geometries: long, solid rods and short, solid cylinders were quenched from selected temperatures into ice water. The degree of damage was determined through strength measurements and sonic damping analysis. Initial damage occurred at a temperature difference above …

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Signal Theoretic Characterization Of A Function Using Positive Exponential Basis Functions, James Julius Baremore Jan 1968

Signal Theoretic Characterization Of A Function Using Positive Exponential Basis Functions, James Julius Baremore

Doctoral Dissertations

"A signal theory characterization of a time function or signal is a representation of the function throughout a sample interval by an orthogonal basis function expansion. The characterization described here obtains the coefficients in the expansion by processing the input waveform, in real time, through a system of three terminal passive RC filters. The outputs of the filters are sampled periodically and the coefficients of the basis function expansion in that interval are related to these values. The basis functions result from an exponential transformation applied to the Legendre polynomials and are orthogonal in time over the sample interval. The …

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Analysis Of A Focus Log Electrode In A Non Homogeneous Medium, John Julian Zenor Jan 1968

Analysis Of A Focus Log Electrode In A Non Homogeneous Medium, John Julian Zenor

Doctoral Dissertations

"The mathematical model presented for the focused logging system is applicable to any resistance logging tool of the electrode type. Horizontal or cylindrical resistance interfaces may be included in any combinations. The tool and its environment are compartmentalized, and the integral form of the condition for continuity of current is applied to each compartment. Acceleration methods are applied to the iterative solution of the resulting large-scale system of linear equations. Two specific models are presented, one for the study of the effects of invasion and the other for the study of the effects of bed thickness on the apparent resistivity …

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Decomposition Of Cr(Oh)₃ To Form Active Cr₂C₃, Timothy A. Clancy Jan 1968

Decomposition Of Cr(Oh)₃ To Form Active Cr₂C₃, Timothy A. Clancy

Doctoral Dissertations

"This study was concerned with the sinterability of Cr₂C₃ powders produced by the calcination of a Cr(OH)₃ gel. The decomposition of the gel was investigated by thermogravimetric analysis, X-ray analysis and microscopic examination. Comparison was made between the size of crystallites as determined by X-ray line broadening and the size of aggregated particles as determined by independent means. These lineal measurements were compared to surface area measurements on the calcined powders. The degree of sinterability was judged from the density measurements on Cr₂C₃ pellets fired under air, oxygen and nitrogen atmospheres. Energies of activation of 25 and 20 kilocalories per …

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Hrva - A Velocity Analysis Technique For Seismic Data, John Charles Robinson Jan 1968

Hrva - A Velocity Analysis Technique For Seismic Data, John Charles Robinson

Doctoral Dissertations

"A High-Resolution Velocity Analysis (HRVA) has been developed for the determination of the root-mean-square subsurface-velocity energy spectrum from gated seismic data which has been normal-moveout corrected. All calculations are performed in the frequency-space or frequency-wavenumber domain; seismic gates are transformed from the time-space domain via the Fast Fourier Transform algorithm. HRVA is not restricted to the investigation of apparent horizontal velocities which have associated stepout values that are integral multiples of the time sampling interval, as are the existing correlation techniques. The technique liberally exploits the inexistence of significant energy in the higher frequency harmonies of seismic data, resulting in …

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Effect Of Micelles On Flotation Of Metal Ions, Uriel Michael Oko Jan 1968

Effect Of Micelles On Flotation Of Metal Ions, Uriel Michael Oko

Doctoral Dissertations

"A study of the anionic surfactant, sodium dodecyl sulfate (SDS), and the dependency of the adsorption of divalent metal counterions such as copper and zinc at the air-water interface on its concentration in the solution, was undertaken in order to better understand the process of ion flotation. The study is divided into two broad categories, the first of which consists of the evaluation of the extent of aggregation of the surfactant molecules into micelles, and the effect of the divalent metal counterion concentration on this aggregation and on the critical concentration at which micelles start forming (cmc). This was accomplished …

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A Novel Method For Solving The Uniform Distributed Network Analysis Problem, Robert C. Peirson, Edward C. Bertnolli Jan 1968

A Novel Method For Solving The Uniform Distributed Network Analysis Problem, Robert C. Peirson, Edward C. Bertnolli

Electrical and Computer Engineering Faculty Research & Creative Works

An application of the Laplace transform method of Ogata to the solution of the uniform distributed network analysis problem is described. Copyright © 1968 by The Institute of Electrical and Electronics Engineers, Inc.

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Recombination Statistics For Neutron Bombarded Silicon Transistors, M. C. Chow, J. L. Azarewiczt, C. A. Goben Jan 1968

Recombination Statistics For Neutron Bombarded Silicon Transistors, M. C. Chow, J. L. Azarewiczt, C. A. Goben

Electrical and Computer Engineering Faculty Research & Creative Works

This paper presents a recombination statistical model for the neutron-induced base current component reported previously. The derivation was based on the following: 1) the current equation for the induced current component developed previously; 2) the Shockley-Read-Hall statistics for holes and electrons; and 3) the recombination statistics derived by Sah, Noyce and Shockley for sites in the bulk space-charge region. The recombination statistics model depends on the diffusion potential, the junction voltage, the activation energy, temperature, and the ratio of capture cross-sections for holes and electrons. The utility of such a recombination statistical model is illustrated by using measured parameters to …

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Radiation And Annealing Characteristics Of Neutron Bombarded Silicon Transistors, L. S. Su, G. E. Gassner, C. A. Goben Jan 1968

Radiation And Annealing Characteristics Of Neutron Bombarded Silicon Transistors, L. S. Su, G. E. Gassner, C. A. Goben

Electrical and Computer Engineering Faculty Research & Creative Works

Operating a silicon planar epitaxial transistor in the inverse configuration allows one to demonstrate clearly the importance of the neutron-induced base current component and its degradation of the emitter efficiency, and, because of the much larger depletion layer, to compute a volume dependent damage constant applicable to all silicon p-n junctions. The importance of minimizing the absolute change versus relative change in radiation hardening studies is clearly illustrated. Surface effects were found to be significant for transistors mounted in gas-filled cans. The diffusion potential was predicted, on theoretical grounds, to vary with neutron fluence, and the theory was experimentally confirmed. …

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Design Of Truncated Sequential Tests For Rapidly Fading Radar Targets, Norval D. Wallace Jan 1968

Design Of Truncated Sequential Tests For Rapidly Fading Radar Targets, Norval D. Wallace

Electrical and Computer Engineering Faculty Research & Creative Works

Curves and equations are presented from which the exact performance of truncated sequential tests can be determined for one important case: the biased square-law detector for the detection of rapidly fading targets. The method of generating functions is used to derive probability distributions for sample size. It is shown how these probability distributions can be used to determine truncation errors and the effects of multiple-resolution elements. Sample calculations are performed to determine the effects of a particular truncation procedure. Copyright © 1968 by The Institute of Electrical and Electronics Engineers, Inc.

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Electric Field Investigations And A Model For Electrical Liquid Spraying, Wallace E. Deshon, Ralph S. Carson Jan 1968

Electric Field Investigations And A Model For Electrical Liquid Spraying, Wallace E. Deshon, Ralph S. Carson

Electrical and Computer Engineering Faculty Research & Creative Works

The equation generally used for determining the electric field at the liquid tip in electrical spraying of liquids was originally derived for determining the electric field around a metal tip in the extraction of electrons from metals. In the present paper experimental data were taken at the instant of spraying to determine the validity of using this equation for liquid tips. the results indicate that the value of electric field given by this equation needs to be increased by about 20% in the normal range of operation. A model for the spraying mechanism of the liquid is also presented. © …

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The Identification And Evaluation Of Toxic Effects Of Organic Micropollutants, John Warren Smith Jan 1968

The Identification And Evaluation Of Toxic Effects Of Organic Micropollutants, John Warren Smith

Doctoral Dissertations

No abstract provided.

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Semiempirical Determination Of The Differential Fast Flux Spectrum For U-235 Fission With Water Moderator, Henry Anthony Till Jan 1968

Semiempirical Determination Of The Differential Fast Flux Spectrum For U-235 Fission With Water Moderator, Henry Anthony Till

Masters Theses

"The differential fast flux spectrum of the UMR Pool Research and Training Reactor core was determined by simultaneous activations of threshold foil detectors by neutron-nucleon reactions. This represents one phase of the composite neutron environment at two sample irradiation locations and the center of a fuel element during a power operation of 200 Kw (th). To accomplish this measurement a semiempirical least-squares approximation fitting activation date to a theoretical Cranberg U-wet fission spectrum was applied. This is a technique designed specifically for water moderated systems and takes into consideration both virgin and down-scatter neutrons. Gamma decay photopeaks were reduced using …

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Transient Response Of A Class Of Distributed Systems, Jaw-Shyong Tzeng Jan 1968

Transient Response Of A Class Of Distributed Systems, Jaw-Shyong Tzeng

Masters Theses

"The transient response of uniform distributed systems with any transfer function that is rational in w=e[square root of Ts] can be analyzed with the basic form of the transfer function [1 over (w-a)] after partial fraction expansion, where the pole a can be real or complex in the w plane. with the complex pole within the stable region in the w plane, there are only two possible combinations of the basic transfer function [1 over (w-a)], i.e. [1 over (w-a)] ł [1 over (w-a*)], for physical realizability. The imaginary part of the transient response of the basic transfer function [1 …

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A Simple Design Algorithm For Synthesis Of Multilevel Combinational Networks, James H. Tracey Jan 1968

A Simple Design Algorithm For Synthesis Of Multilevel Combinational Networks, James H. Tracey

Electrical and Computer Engineering Faculty Research & Creative Works

An algorithm is presented for the synthesis of combinational networks with a constrained arrangement of ANDS, ORS, NANDS, NORS, and inverters. The algorithm is easily presented to students in an introductory logic design course and has considerable application in modern practical logic design. Many texts available for a first course in logic design give very limited practical guidance for synthesis of networks under constraints outlined here. It is suggested that the algorithm presented here be furnished as supplementary material in the introductory course. Copyright © 1968 by The Institute of Electrical and Electronics Engineers, Inc.

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A Study Of A Model-Referenced Adaptive Control System, James William Graham Jan 1968

A Study Of A Model-Referenced Adaptive Control System, James William Graham

Masters Theses

"A model-referenced adaptive controller for a first-order plant with time-varying parameters is developed using Lyapunov's second method. The system is studied with the aid of analogue computer simulation and an oscillatory mode is encountered. A method of reducing the oscillations by addition of a compensating network is proposed. The compensation is obtained through the use of linearization and root locus techniques. The compensated system shows a much improved error response over the original system"--Abstract, page ii.

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A Method Of Supervised Pattern Recognition By An Adaptive Hypersphere Decision Threshold, Darroll Steven Mccormack Jan 1968

A Method Of Supervised Pattern Recognition By An Adaptive Hypersphere Decision Threshold, Darroll Steven Mccormack

Masters Theses

"In this study the Bayes likelihood detector is combined with an adaptive decision threshold classifier to solve the multicategory pattern recognition problem. It is assumed that the pattern classes can be represented by an n-dimensional vector sample taken from a multivariate gaussian probability distribution. This study presents (1) the derivation of the A̲daptive H̲ypersphere D̲ecision T̲hreshold classifier (AHDT classifier) and shows (2) how the AHDT classifier minimizes the probability of error using the learning patterns. Finally the AHDT classifier is applied to the solution of a physical problem through computer simulation"--Abstract, page ii.

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A Simulation Of The Transistor By Computer Using The Linvill Diffusion Model, Clifford D. Skouby Jan 1968

A Simulation Of The Transistor By Computer Using The Linvill Diffusion Model, Clifford D. Skouby

Masters Theses

"This investigation involves the construction of an analog computer model of the transistor. The computer model is based upon the Linvill diffusion model. The equations for the Linvill diffusion model were programmed on the computer by making certain approximations. Different models, using different approximations, were used for the different regions of operation of the transistor. A composite analog model was constructed by combining the models for the restricted regions, giving a general model good for all regions of transistor operation. This analog diffusion model was modified to account for the effects of junction capacitance and base resistance. The modified analog …

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An Unsteady-State Method For Determining The Thermal Conductivity Of Materials, Richard H. Bulmer Jan 1968

An Unsteady-State Method For Determining The Thermal Conductivity Of Materials, Richard H. Bulmer

Masters Theses

"Originally this work was initiated to develope [sic] a method for measuring the thermal diffusivity and thermal conductivity of metals. Due to the characteristics of the method and the equipment used, it was concluded that the technique is not suitable for materials of high conductivity. However, results show that the apparatus is valuable for the determination of the thermal diffusivity of relatively poor heat conductors. The favorable characteristics of the method are its rapidity and basic simplicity"--Abstract, page ii.

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An Ultrasonic Pulse Generator Using The Transducer As A Frequency Determining Element, Donald E. Watke Jan 1968

An Ultrasonic Pulse Generator Using The Transducer As A Frequency Determining Element, Donald E. Watke

Masters Theses

"This paper describes the development of a method of ultrasonic pulse generation in which the transducer determines the frequency of oscillation. A definite advantage of this method is the ability of the frequency of oscillation to change with changes in the transducer mechanical resonant frequency. This maintains peak efficiency at all times. The method is demonstrated in a small sonar transmitter but could be applied to any area involving driven ultrasonic transducers"--Abstract, page ii.

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Coupled Transport Of Heat And Mass In Laminar Tube Flow, Lung-Mau Huang Jan 1968

Coupled Transport Of Heat And Mass In Laminar Tube Flow, Lung-Mau Huang

Masters Theses

"The object of this investigation is to study the mutual dependence of heat and mass transport in laminar and hydrodynamically developed tube flow. Consideration is given to gas flow through a tube whose wall is coated with a sublimable materials so that heat and mass transfers take place between the wall and the flowing gas stream. The tube wall is thermally insulated from the external environment, with the result that the latent heat required by the sublimation process at the wall is supplied solely by convective transfer from the gas. The analysis of the problem requires simultaneous solution of the …

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Optical Reflectance Spectra Of Chromium (Iii) In Mgo-Ss, Thomas Spencer Montgomery Jan 1968

Optical Reflectance Spectra Of Chromium (Iii) In Mgo-Ss, Thomas Spencer Montgomery

Doctoral Dissertations

"The valence state and coordination site of the transition-metal ion, chromium, was investigated in a MgO host lattice. The chromium ion incorporated into poly-crystalline MgO by quenching from elevated temperatures allowed investigation of a single crystalline phase, MgO-solid solution (ss). The chromium ion was confirmed to occur in the trivalent state and to occupy octahedral cation sites in the MgO lattice by the use of optical reflectance spectroscopy. The effect of the concentration of the chromium ion on the crystal field splitting energy, 10 Dq, permitted analysis over a range of Dq/B values. In conjunction, MgO-ss lattice parameters examined as …

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Compressive Creep Of Basic Refractories, Maurice E. Green Jan 1968

Compressive Creep Of Basic Refractories, Maurice E. Green

Masters Theses

"The microstructure and mineralogical composition of direct bonded, 50 wt.% magnesia - 50 wt.% chrome ore refractory compositions containing controlled additions of silica were correlated with their compressive creep behavior in the temperature range 1450⁰ to 1550⁰C under stresses of 100 to 175 psi. Steady state creep rates were determined from the linear regression of the steady state regions of deformation on time. Apparent activation energies and deformation flow characteristics were determined from the temperature and stress dependence of the steady state creep rates. Silica contents up to 3.5 wt.% increased the amount of direct intergranular bonding which decreased the …

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Investigation Of Thermal Resistance At The Interface Of Dissimilar And Similar Metals, Ching-Liang Lin Jan 1968

Investigation Of Thermal Resistance At The Interface Of Dissimilar And Similar Metals, Ching-Liang Lin

Masters Theses

"Experiments have been conducted to investigate the resistance and the effect of the directional heat flow at the interface of metals in contact. The test specimens were cylinders, axially aligned and dead weight loaded. Specimen materials were aluminum, bronze, and steel. The tests were conducted at environment pressures of 5x10⁻⁵ Torr. or less. The dead weight load was kept at 10 lbs. for all tests and the surface roughness for all specimens was from 6 to 8x10⁻⁶ inch. The results of the investigation reveal that the resistance to heat flow at the interface of metals decreases as the interface temperature …

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An Intensity Regulation System For A Monochromator, David A. Wayne Jan 1968

An Intensity Regulation System For A Monochromator, David A. Wayne

Masters Theses

"In the investigation of phenomena involving both optical intensity and wavelength, an instrument is often desired which allows one of the quantities to be held constant while the other is varied. A relatively inexpensive system is described which utilizes a commercial grating monochromator and external feedback electronics to regulate the output intensity as the wavelength is varied. In this system, a sample of the output intensity is taken by a photosensor with known spectral response. The output of the photosensor is then compared electronically with that of a pre-programmed function generator which cancels nonlinearities in the photo-sensor. The resulting signal …

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The Effect Of Prior Cold Work On The Pressure Welding Of Ferritic Nodular Iron, Ronald Morris Ledbetter Jan 1968

The Effect Of Prior Cold Work On The Pressure Welding Of Ferritic Nodular Iron, Ronald Morris Ledbetter

Masters Theses

"The purpose of this investigation was to determine the effect of prior cold work by swaging on the pressure welding of ferritic nodular iron. Test pressure welds were produced from continuously cast ferritic nodular iron in the as cast condition and with prior cold work of 20, 30, 40, and 50 per cent reductions in area. Welding pressures of 23,500 psi, 35,300 psi, and 47,100 psi were employed. All welds were made at interface temperatures of 2000°F. Welds made with the as cast material at high welding pressures possessed relatively low tensile strengths due to the creation of planes of …

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Design And Construction Of A Liquid Nitrogen Cryostat For Use In A Swimming Pool Type Reactor, Bruce B. Joiner Jan 1968

Design And Construction Of A Liquid Nitrogen Cryostat For Use In A Swimming Pool Type Reactor, Bruce B. Joiner

Masters Theses

"The continued expansion of the nuclear reactor facility and the nuclear engineering program dictates the need that a liquid nitrogen cooled cryostat be available at the reactor. This unit would be available for use in graduate and undergraduate laboratories and for graduate research. A liquid nitrogen cooled cryostat capable of maintaining a sample between 77°K to 80°K for an extended period of time in or adjacent to the core of the reactor was designed, constructed, and successfully operated. Recommendations were made for possible modifications to expand the versatility of the system"--Abstract, page ii.

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Analytical And Experimental Methods For Determining The Properties Of Materials At Very High Rates Of Loading, A. G. Behring Jan 1968

Analytical And Experimental Methods For Determining The Properties Of Materials At Very High Rates Of Loading, A. G. Behring

Masters Theses

"In the following report, some of the properties of ALCOA 7075 T651 aluminum, when subjected to high rates of loading, are experimentally investigated by impacting two rods of the material longitudinally. One rod is accelerated to a uniform velocity with an air gun launcher. The stationary second rod is instrumented with strain gages on its lateral surface in order to determine the strain-time history following impact. A detailed description of the experimental equipment is included. Simple, one-dimensional theory is used to determine the dynamic, elastic modulus of the test material under the impact condition. Several observations regarding the behavior of …

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