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The Mechanism Of Second Breakdown In Transistors, Eugene David Fabricius

Dissertations

The purpose of this dissertation is to examine the behavior of electrons and holes in a semiconductor or diode under conditions of high current density as a function of temperature, and to relate this behavior to the phenomenon of Second Breakdown. The approach used is that of magnetohydrodynamics, the electrons and holes being treated as a plasma "gas" embedded in the dielectric of the semiconductor.

This approach is unique in the following respects:

1. This is the first attempt to explain second breakdown in terms of magnetohydrodynamics.
2. This is the first time an explanation of pinching in a solid at room …

The Generalized Virial Equation Of State, Ghanshyam R. Patel

Dissertations

A generalized three parameter virial equation of state has been developed and tested for seven pure gases having different molecular characteristics. The equation has also been tested for more than thirteen binary gas mixtures using three different mixture rules. The final equation is as follows:

Z = 1 + B(T)/V + C(T)/V² + D(T)/V³ + E(T)/V⁴ + VF(T)/e^aV + VG(T)/e^bV

The expressions for E(T), F(T), and G(T) along the critical isotherm were derived in terms of critical properties and two constants, a and b which appear in the sixth and seventh terms in the above …

The Plasticization Of 4-Methyl-Pentene-1 (Tpx-Rt-D30) Polymer With Petroleum Jelly, Joseph P. Mccann

Theses

The properties of TPX-RT-D30 (4-methyl-pentene-1 polymer) have been changed by blending petroleum jelly with the polymer. The polymer was blended in a Brabender apparatus with up to 40% by weight petroleum jelly (P.J.) at 270°C, pressed and quenched in water. Samples were die cut for the various tests. The polymer tensile properties (ASTM-638-64T) showed both a break and yield value in all ratios as compared to only a break value for the TPX-RT polymer. Breaking strength ranged from 4000 psi for pure TPX-RT down to 1000 psi at 40% P.J., with a leveling point of 2000 psi at 15% P.J. …

Critical Interaction Constants For Binary Gas Mixtures For Use In The Redlich-Kwong Equation Of State, Warren J. Biss

Theses

In this work, critical interaction constants were used to evaluate the interaction coefficients of the Redlich - Kwong constants for bin-ary gas mixtures. From these constants, the pressure - volume - temperature behavior of the mixtures was calculated using the Redlich - Kwong equation.

The critical interaction constants, T₁₂ and P₁₂ , were evaluated for binary mixtures by solving, simultaneously, two second degree equations relating terminal slopes for critical pressure loci and the mole fractions of the components present. The feasibility of this method was tested by calculating P-V-T data for binary mixtures and comparing this with values …

The Effect Of Nitrilotriacetic Acid Upon The Biodegradability Of Linear Alkyl Benzene Sulfonate, John D. Mckenna

Theses

The effects of trisodium nitrilotriacetate (SKTA) and sodium tipolyphosphate (STPP) upon the biological degradation of linear alkyl benzene sulfonate (LAS) ware experimentally investigated by the chemical oxygen demand and methylene blue methods. It was found that when STPP was present with LAS, the degradation of the LAS was better than when alone in solution. It was also found that LAS in solution with SN TA was less degradable than LAS alone. The benzene ring of the MS appeared to degrade after most of the linear portion of the chain had already been degraded.

Effect Of Column Diameter On The Frequency Response Of Water Fluidized Beds, Edward C. Maiuro

Theses

The effect of column diameter on the frequency response of water fluidized beds was investigated.

Studies were made on four columns ranging from four to ten inches in diameter. Water was used to fluidize the beds which consisted of spherical glass beads .0185 inches in diameter. A trace solution of sodium chloride was sinusoidally introduced into the beds. Inlet and outlet concentrations were continuously measured by an electrical conductivity recorder. Separate frequency response tests were conducted on the inlet calmning section in an attempt to obtain the frequency response of this region alone. Results of the tests were expressed as …

A Correlation Of Latent Heats And Densities Of Pure Organic Liquids From Known Vapor Pressure Data, Vincent J. Vasta

Theses

Employing the correlation developed by Kemme (5), which is based on a hole model for a liquid, relating vapor pressures with corresponding liquid densities and the number of carbon atoms in a molecular chain for a homologous series, correlation coefficients were established using multi-linear regression analysis on available literature data. This correlation was newly applied to several straight chain homologous series including the n-acids, formate esters and n-alkyl benzenes.

A second correlation developed by Kemme (5) relating vapor pressure, internal heat of vaporization and the number of carbon atoms for a homologous series was employed to determine correlation coefficients for …

The Optimization Of A Catalytic Methanol Reactor, Peter Wrampe

Theses

The development of a computer program which determines the minimum space time of the methanol synthesis reactants is presented. Also, the optimum temperature profile along the catalytic reactor was predicted for a desired conversion at a given operating pressure, feed composition, and catalyst effectiveness factor.

The equilibrium conversion of methanol was determined at various reaction parameters. Rates of reaction were ascertained and maximized with respect to temperature for various conversions and given reaction parameters. The results, along with those obtained when the design equation was numerically integrated, were compared to published data. Equations were established for various sets of published …

Realization Of Transfer Impedances Using Distributed Rc Elements In A Common Ground Linvill Configuration, Walter Woronka

Theses

One of several synthesis procedures available for the realization of a transfer admittance is that of Linvill. This synthesis procedure employs an active element, a negative impedance converter (NIC), to shift the poles of passive immittance functions from the negative real axis into the complex plane to realize the desired transfer immittance function.

The Linvill synthesis procedure is extended to networks containing cascaded distributed RC elements and the conditions which must be satisfied to realize a transfer impedance using these distributed elements are defined.

Premix Molding Compounds : The Effect Of Processing Technique On Profitability And Product Integrity, Albert Robert Kurkowski

Theses

Premix molding compounds, presently manufactured in a double-armed blade kneader mixer, can now be prepared by a new and unique method utilizing a high speed densifier. Compounds processed in a kneader mixer, by virtue of its overlapping, shear mixing motion, are extremely susceptible to glass fiber degradation and. consequent mechanical strength reductions in moldings. Previously, as this was the only equipment, available with the capability to admix highly viscous materials, processors would formulate and design to compensate for the resultant property reductions that are encountered. Also typical of conventional kneader mixer processes is an inherent materials handling problem and mixing …

Test 980: Minneapolis-Moline G900 Gasoline (Also G950 Gasoline), Nebraska Tractor Test Lab

Nebraska Tractor Tests

EXPLANATION OF TEST REPORT GENERAL CONDITIONS East tractor is a production model equipped for common usage. Power consuming accessories can be disconnected only when it is convenient for the operator to do so in practice. Additional weight can be added as ballast if the manufacturer regularly supplies it for sale. The static tire loads and the inflation pressures muse conform to recommendations in the Tire Standards published by the Society of Automotive Engineers. PREPARATION FOR PERFORMANCE RUNS The engine crank case is drained and refilled with a measured amount of new oil conforming to specifications in the operator’s manual. The …

Test 978: Minneapolis-Moline G900 Diesel (Also G950 Diesel 10-Speed), Nebraska Tractor Test Lab

Nebraska Tractor Tests

EXPLANATION OF TEST REPORT GENERAL CONDITIONS East tractor is a production model equipped for common usage. Power consuming accessories can be disconnected only when it is convenient for the operator to do so in practice. Additional weight can be added as ballast if the manufacturer regularly supplies it for sale. The static tire loads and the inflation pressures muse conform to recommendations in the Tire Standards published by the Society of Automotive Engineers. PREPARATION FOR PERFORMANCE RUNS The engine crank case is drained and refilled with a measured amount of new oil conforming to specifications in the operator’s manual. The …

Test 979: Minneapolis-Moline G900 Lpg (Also G950 Lpg), Nebraska Tractor Test Lab

Nebraska Tractor Tests

EXPLANATION OF TEST REPORT GENERAL CONDITIONS East tractor is a production model equipped for common usage. Power consuming accessories can be disconnected only when it is convenient for the operator to do so in practice. Additional weight can be added as ballast if the manufacturer regularly supplies it for sale. The static tire loads and the inflation pressures muse conform to recommendations in the Tire Standards published by the Society of Automotive Engineers. PREPARATION FOR PERFORMANCE RUNS The engine crank case is drained and refilled with a measured amount of new oil conforming to specifications in the operator’s manual. The …

Joining Graphite To Graphite With Transition Metal Foils, Donald James Sandstrom

Chemical and Biological Engineering ETDs

A study has been undertaken to determine the relationship of metallic-foil joining and joining parameters to the strength of joints in a high-quality extruded nuclear graphite. The materials chosen for investigation as joining materials on the graphite of interest were considered to be representative of the Group IVA, VA, and VIA transition metals and iron. The parameters used for joining yielded either a fully diffused joint, which was not temperature-limited with respect to service conditions or a continuous-carbide-interface joint, which was temperature -limited. The metal chosen from Group IVA for joining was zirconium in the form of 0.0005 in. -thick …

Mass Transfer Of Oxygen In Sodium Cold Traps, Charles Clellan Mcpheeters

Nuclear Engineering ETDs

Cold traps have been used extensively for controlling oxygen concentration in sodium systems. Cold traps utilize the positive temperature dependence of the solubility of sodium monoxide in sodium and the resultant precipitation of sodium monoxide at low sodium temperatures. Sodium monoxide precipitation is here assumed to be heterogeneous because of the strong effect of surface area on the precipitation rate shown in previous packless cold trap experiments. Growth of crystals from a super-saturated solution is said to proceed according to the equation

where dm/dt is the rate of mass accumulation on the crystal, k is an over-all mass transfer coefficient …

An Experimental Study Of Soil-Structure Interaction, Stephen Connally Mitchell

Civil Engineering ETDs

Experimental data obtained from a series of static arching tests run on vertically oriented rigid-base cylindrical structures buried in a partially saturated low plasticity soil are presented. The experimental results are compared to an available analytical approach. The axial stiffness of the structure, the confined tangent modulus (stiffness) of the soil, and the applied surface overpressure were varied. The most important measurement in this experimental study was the total load carried by the structure for different values of structural stiffness and soil stiffness. The index properties, as well as the shear strength and angle of internal friction for the soil …

A Soil Stress Gage Evaluation., Caryl Martin Reiff

Civil Engineering ETDs

The static evaluation of a recently developed soil-stress gage, primarily designed for laboratory use in dry cohesionless soils, is presented. Two variations of the same basic soil stress gage design are discussed. Tests were performed to evaluate the gage linearity, temperature sensitivity, and electrical response to applied soil pressure. The gage responded linearly to pressure and the calibration curves remained stable within ± 5 percent over a period of two years. With a 10 ma bridge current, the gage had an output sensitivity of 0.040 mv per psi. Temperature changes produced signals which could not be distinguished from pressure signals. …

A Study Of Delta Modulation And Its Application To Control Communication, Robert H. Maschhoff

Electrical and Computer Engineering ETDs

This thesis is a study of certain aspects of delta modulation which are of particular interest or significance in control system communication. Delta Modulation is a discrete difference encoding method in which the amplitude difference between the signals occurring at two points in time can be transmitted as a plus one or a minus one bit. Such a method of encoding has a rate of change capacity limit rather than a hard amplitude bound.

A determination of the sampling rates, and therefore bit rates, necess­ary to encode several types of signals is reported. Signals which themselves have a rate-limited characteristic …

Temperature Distribution Within Aspalt Pavements And Its Relationship To Pavement Deflection, Herbert F. Southgate, Robert C. Deen

Kentucky Transportation Center Research Report

No abstract provided.

Bridge Paint Specifications, Proposed Revisions, James H. Havens

Kentucky Transportation Center Research Report

During the past several years, I have devoted considerable attention and study to bridge-paint systems and specification -- in an attempt to keep abreast with developments and current practices throughout the country. My first proposal (July 30, 1958; copy appended) was motivated by development of a then-new rust-inhibitive pigment suggested by National Lead Company. The pigment had shown considerable promise as a substitute for red lead and appeared in many respects to be superior to red lead -- on of which was economy.

Construction And Performance Of Trial Section Of Treated Shoulders On The Mountain Parkway Extension, Robert L. Florence, Tommy C. Hopkins

Kentucky Transportation Center Research Report

In October 1966, J.W. Spurrier, Assistant Operations Management Engineer, requested that the Research Division make a study of a two-mile section of the shoulders on the Mountain Parkway Extension in Wolfe County (from Mile Post 43.8 to Mile Post 45.8) and make recommendations for design and construction procedures for cement stabilization of the shoulders. In compliance with this request, in January 1967, Research Division personnel made a survey of the full length of shoulder on the Mountain Parkway Extension. Included in this survey were measurements of depth of the dense graded aggregate, penetrations of the shoulder subgrade soil and samples …

Investigation Of Use Of Preformed, Compressed Neoprene Seals In Joints Of Concrete Bridge Decks, Dennis L. Willaman

Kentucky Transportation Center Research Report

Progressive deterioration and staining of concrete bridge substructures and erosion of abutments may, in many instances, be attributed to the leakage of bridge deck joints. The primary difficulty in maintaining a properly sealed joint is the continual expansion and contraction of the bridge spans. Joint seals, of course, must remain in contact with both faces of the disjointed sections and remain flexible at all temperatures encountered.

A study was initiated by the Division of Research for the specific purpose of evaluating the performance of preformed, compressed neoprene seals and to compare the performance of these seals with the performance of …

The Development Of An Instrument For Three Dimensional Analysis Of Micron Quantities Of Tooth Movement, M. Clark Lamberton

Loma Linda University Electronic Theses, Dissertations & Projects

In order to quantitate initial tooth movement in response to forces applied to the tooth crown, an instrument for intraoral use has been developed. The photomicrometer consists of nine photosensitive cells mounted in an assembly of two layers. Eight of the cells were mounted to form X and Y axes, top layer and bottom layer, to measure horizontal movements. The ninth cell was mounted in the center of the bottom layer and was used for alignment and for measurements in the Z or vertical axis. The photocell assembly was approximately 10 mm diameter and 6 mm high. This assembly when …

X-Ray Irradiation Studies Of Lybian Desert Glass And Sand, Magdi M. Nasrallah

Archived Theses and Dissertations

No abstract provided.

Design Of Linear Control Systems With Distributed Parameter Elements By Parameter Plane Techniques, Murray Weinberg

Dissertations

This dissertation extends the application of parameter plane techniques to a number of areas. Specifically, the parameter plane technique can now be used to determine absolute stability, relative stability, and the location of roots of the closed-loop characteristic equation of systems containing both lumped and distributed parameter elements. The advantages of utilizing this technique are that results can be obtained as two system parameters are varied simultaneously and higher order systems can be treated as easily as low order ones.

Investigation of the mapping of real roots resulted in the derivation of a theorem which relates the number of real …

Noise Spectral Density As A Diagnostic Tool For Reliability Of P-N Junctions, Young Duck Kim

Dissertations

The feasibility of choosing noise-voltage spectral density as a prediction parameter for the degradation of p-n junctions has been examined both theoretically and through a series of life-tests.

Experimental facts show that the noise-voltage spectral density, S_v(w), observed in a p-n junction under the breakdown condition tends to be "white" (which contradicts the 1/f-noise theory), and S_v(w) is inversely proportional to the breakdown current (which contradicts the shot-noise theory). Furthermore, some p-n junctions display one or more multiple peaks of S_v(w) at different current levels which can not be explained by any of the …

An Analysis Of The Effects Of Ionizing Radiation In One-Dimensional Metal-Oxide-Semiconductor Structures, Charles William Gwyn

Electrical and Computer Engineering ETDs

Previous investigations of the radiation effects in Metal­Oxide-Semiconductor (MOS) devices have shown that ionizing radiation produces a trapped space charge in the oxide which causes a shift in the electrical characteristics of the device. Several models have been proposed to explain the observed change in the MOS device characteristics as a function of nuclear radiation exposure. Although these models have qualitatively explained the change in device characteristics, they have not adequately explained the physical processes producing the charge buildup nor have they considered the detailed conduction and charge trapping processes which exist in the various regions of an MOS structure. …

Electromagnetic Scattering From A Statistically Rough Spherical Surface With Shadowing, James Albert Doran

Electrical and Computer Engineering ETDs

Significant errors may be introduced into the theoretical calculation of scattered fields from a roughened sphere by the use of erroneously derived shadowing probabilities. These shadowing probabilities, of recent appearance in the literature, had been derived using an infinite plane as the mean surface. This paper undertakes the derivation of shadowing probabilities using a spherical mean surface. Although closed form expressions could not be obtained, computer evaluation of a "correction factor" showed that the errors incurred through use of the infinite plane probabilities (rather than the spherical surface) are insignificant. The class of rough surfaces considered was with a gaussian …

Measurement Of Deformations An A Large Displacement Gradient Field, Lowell P. Martin

Mechanical Engineering ETDs

A summary of the general kinematical theory of finite deformations is presented together with analyses of the specific deformations of sim­ple shear, bending of a block and bending of an initially curved cuboid.

The moiré fringe equations for large homogeneous deformation are developed. The extension to the nonhomogeneous case is presented and specific analyses are given for the deformations noted above. The moiré theory is combined with the results of the large deformation analyses.

Theoretical results are verified by the study of geometrically produced moiré patterns, and by actual experiments conducted on syn­thetic rubber specimens. The experiments included the deformations …

Liquid Vapor Equilibrium In Nucleate And Film Boiling, Walter Henry Rothaug

Theses

Liquid vapor equilibrium data were obtained for several solutions and azeotropes under both nucleate and film boiling. The data were invariant between the two boiling regimes indicating that both nucleate and film boiling are equilibrium vaporizations rather than either diffusional or bulk vaporizations. Boiling heat transfer versus temperature data were taken in nucleate and film boiling for the solutions and azeotropes and for several pure liquids. The critical heat flux for methyl alcohol-benzene solutions rose sharply at first and then more moderately with increasing alcohol concentration. The critical heat flux was pratically constant regardless of concentration in ethyl alcohol-benzene solutions. …