Digital Commons Network^™

Reliability Aspects Of Semiconductor Surface Protective Coatings, Robert Edward Mcmillan

Dissertations

This research was directed towards the occurrence and im-portance of surface leakage in reverse biased semiconductor diodes and the relation of this leakage to the reliability of a device under use conditions. As a result of this study, it is possible to predict one important leakage mechanism after such back-biased diode units have been subjected to long periods of temperature and humidity. This theory is consistent with tests of commercially available units, some of which have very slight surface leakage and others very large surface leakage.

Further, the usefulness of various possible passivating coatings is critically analyzed on the basis …

Dynamic Stress Concentrations About An Epilliptical Discontinuity In An Elastic Solid, Kenneth Roy Schroll

Dissertations

The redistribution of dynamic stresses caused by the presence of an elliptical discontinuity in an infinite isotropic homogeneous elastic solid is examined. The solutions are obtained for the special cases of the rigid immovable inclusion and the vacuous cavity inclusion, and numerical results are presented.

The solutions to the wave equations in elliptical coordinates are expressed in series of the elliptical geometry eigenfunctions. Application of the boundary conditions, vanishing displacements for the rigid immovable inclusion and vanishing stresses for the cavity inclusion, yields in each case two infinite sets of linear algebraic equations for the expansion coefficients of the series …

Oscillations In Pulse Frequency Modulated Control Systems, Warren Joseph Guy

Dissertations

This dissertation is concerned with oscillations and their stability which occur in a control system containing two nonlinearities, separated by linear elements. Specifically the nonlinearities are Integral Pulse Frequency Modulators and the linear elements are described by ordinary differential equations which are linear. The IPFM can be modelled by a quantizer with hysteresis and many other PFM laws are related to IPFM, thus the study applies to more than just IPFM alone.

Boundaries on the system parameters are identified within which free oscillation may be possible. These boundaries give sufficient conditions for stability and necessary conditions for instability. Also since …

The Oxidation Of Sulfur Dioxide In A Regenerative Reactor, Raymond Henry Edgecomb

Theses

A novel dual-unit sulfuric acid converter is depicted that performs in cyclic operation in unsteady state. A mathematical model and IBM 1130 Computer program were developed to show the temperature and conversion profiles in commercial-sized vanadium oxide catalyst beds. In the catalytic oxidation of sulfur dioxide conversions of 95-97% were attained without benefit of conventional heat exchangers. A single exchanger operating in conjunction with the dual-unit system might attain conversions as high as 99%.

Batch Heat Transfer To Suspensions In An Agitated Vessel, John Philip Horzepa

Theses

Batch heat transfer data was experimentally determined for two phase (solid?liquid) systems in a baffled agitated vessel. Three iron oxide and water and two kaolin and water suspensions were evaluated and were found to be pseudoplastic. A total of 231 heating and cooling data points were examined. Each suspension was evaluated using anchor, paddle, propeller and turbine impellers. Various sizes of the latter three impellers were used.

The experimental heat transfer results for suspensions were compared with the Hagedorn and Salamone correlation for pseudoplastic liquids. Only partial agreement with the more dilute suspensions was obtained. Overall, the data for suspensions …

Determination Of The Electronic State Of Aryl Nitrenes In An Intramolecular C-H Insertion Reaction, Ali Mohammad Khonsari

Theses

β,γ-Dideuteriopropylbenzene was obtained in 84% yield from deuteration of allylbenzene. Nitration of this compound resulted in o-nitro (β,γ-dideuteriopropyl)-benzene. Reduction of this compound gave o-(β,γ-aideuterio-propyl)aniline. o-(β,γ-Dideuteriopropyl)phenyl azide was prepared by dizotization of the aniline compound, followed by treatment with sodium azide.

Decomposition of the azide in isooctane solution by photolysis at room temperature gave no trace of deuterio-2-methylindoline (intramolecular insertion product).

Photolysis of the azide at the reflux temperature of the solvent (99?C) resulted in the formation of deuterated-2-methylindoline as the major product (40%) yield. The reaction is presumed to proceed through an aryl nitrene intermediate. Analysis of the nuclear magnetic …

A Comparative Analysis Of Multicomponent Distillation Minimum Reflux Methods, Joesph H. F. Loozen

Theses

One of the most important factors to know in the design of distillation columns is the minimum reflux ratio. Numerous procedures have been developed for the determination of the value of the minimum reflux ratio for multicomponent mixtures requiring various degrees of computational effort. Shortcut techniques are obviously advantageous with respect to computation time. After reviewing the available methods, those by Underwood, Colburn, Scheibel and Montross, Murdoch and Holland, and Shiras et al. were selected for further evaluation, mainly on the basis of practical potential.

Comparison of these procedures was accomplished by calculating the minimum reflux ratio for a large …

An Economic Evaluation Of A Pressure Sulfuric Acid Manufacturing Plant, Daniel A. Marlin

Theses

The production of Sulfuric Acid at elevated pressures is presented with the economics for operating at one, three, five, seven, nine and thirteen atmospheres. The conventional and pressure plants are compared operating on the same basis.

The basis for a pressure plant design is obtained from an I.B.M. 1130 computer program developed for One Thousand Net Tons per Day of Sulfuric Acid. Recognized operating conditions for a conventional acid plant are incorporated in the pressure plant design program.

Sulfuric Acid manufacture with operating pressures higher than atmospheric, but less than five atmospheres, results in maximum rate of return on investment …

A Computer Program For The Optimization Of Binary Distillation In A Dual-Column System, Richard Vincent O'Lenick

Theses

A computer program is presented for the optimization of a two-column distillation system involving a two-component mixture. The economic reflux ratios in each column are determined using the McCabe-Thiele Method. Activity coefficients are computed by either the Wilson equation, the Margules equation, or both. The program is general and may be used for any binary system where the assumption of constant molal overflow is valid.

Options in the program permit use of either column in separate calculation schemes.

While the optimization effort was prepared in general terms, the initial work was directed toward the acetone-water system. Full data for this …

Effect Of Column Diameter On Mixing In Water Fluidized Beds, Donald P. Schiesl

Theses

In this investigation, the effect of column diameter and flow rate on the mixing characteristics of fluidized beds were studied.

Tests were made on columns of 4, 6, 8 and 10 inches in diameter using water to fluidize glass beads of 0.0185 inches in diameter. The tests were run both at minimum and three times minimum fluidization. Step, impulse, and sinusoidal forcing signals were fed to the columns, using a sodium chloride solution as a tracer with the inlet and outlet concentrations being monitored continuously by a conductivity recorder.

The result of this study showed increased fluid dispersion with increasing …

Packed Column Simulation, Frederick W. Schmidt

Theses

The most difficult and time consuming aspect of the design of packed columns is the hydraulic part. If the designer wants to try many different conditions, many repetitive calculations will have to be performed. Also, some inaccuracy is incurred when trying to use the U.S. Stoneware curves. The graphs are hard to read and almost impossible to interpolate between the parametric lines. The purpose of the program is to give a more accurate calculation by using equations for the pressure drop lines, interpolating between them and correcting for gas density for each foot of packing. The program also allows changes …

The Application Of A Non-Newtonian Rheological Equation To Low-Density Polyethylene, Jeffrey N. Goldstein

Theses

A generalized non-Newtonian equation describing the rheology of molten thermoplastics is verified for low-density polyethylenes. The equation is extended to account for both rheological temperature dependency and polyethylene molecular weight dependency. The prediction of the rheology of new polyethylenes without additional experimentation is thus possible.

The Computer Evaluation Of The Natural Frequencies Of Vibrating Circular Plates With Free, Fixed And Simply Supported Edges, Thomas Michael Juliano

Theses

The natural frequencies of the transverse vibration of a thin, isotropic, circular plate with free, clamped, and simply supported edge conditions were studied extensively. The frequency equation for each edge condition was derived from the classical partial differential equation of plate vibration. These equations, which are in terms of Bessel functions, were then solved numerically to find the natural frequencies. Since the accuracy of the Bessel function values is very important in evaluating these frequencies, a comprehensive digital computer program was devised to calculate these values to eleven digit accuracy. In this Bessel function program four different methods were required …

The Optimization Of A Catalytic Methanol Reactor Using Quench Feed, John Paul Mcburney

Theses

The production of methanol in a catalytic quench feed reactor is studied by means of a computerized model and optimized in terms of total reactor length necessary to achieve a given production rate. The methanol reaction rate can be maximized in a quench reactor through the use of cold stream feeds along the length of reactor.

Since the methanol reaction temperature is restricted to an upper limit of 405°C, the addition of cold stream feed along the adiabatic reactor enables the desired conversion to be reached. For two given levels of conversion, 12% and 15%, an optimum inlet temperature, quench …

The Effect Of Polymerization Variables On Reaction Rate And Intrinsic Viscosity, David H. Smith

Theses

The free radical solution polymerization of vinyl acetate in benzene was studied under simulated commercial conditions. The effects of monomer, initiator, inhibitor, and chain transfer agent concentration on the reaction rate and intrinsic viscosity were examined. The initial reaction rates with monomer concentrations from 40% to 70% and AIBN concentrations from 0.2% to 0.5% were in agreement with the kinetic equation, - d[M]/dT = K[M]² [I]^1/2. After the initial reaction there was an increase in the reaction rate apparently associated with high viscosities, which is consistent with the Trommsdorff effect. The addition of hundredths of a percent …

Test 1044: Allis-Chalmers Crop Hustler 185 Diesel, 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 1043: Allis-Chalmers Crop Hustler 175 Diesel, 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 …

Vacuum Deposition Of Thin Films Of Ultra-High Thickness Uniformity On Conical Substrates Having Extreme Curvature, Richard Bechtel

Electrical and Computer Engineering ETDs

For many industrial and analytical applications of thin films it is very essential to have a uniform thickness of the deposit. In response to this need, various techniques have been devised that are capable of providing the required uniformity on planar and slightly-curved spherical substrates. However, when a severe curvature (such as that encountered with some conical substrates) is introduced, the deposit uniformity that is obtainable with present techniques becomes quite poor. Thus, the need exists for new technology in this respect. Theoretical consideration is given to the problem of obtaining an ultra-uniform thin film coating on conical substrates. The …

Prompt Neutron Decay Constants In A Reflected Fast Burst Reactor, Charles Clayton Price

Nuclear Engineering ETDs

A mathematical model describing the kinetic response of a reflected fast burst reactor is developed using point reac­tor theory. The equations of the model are used to derive a reflected inhour relationship and a two region Rossi-alpha equation.

The model is investigated for three reactor-reflector configurations; the bare reactor, the reactor with a radially symmetric steel reflector, and a reactor with a radially sym­metric polyethylene reflector. This investigation includes the results of a calculational study using Monte-Carlo tech­niques and an experimental program using Rossi-alpha, pulsed neutron, and reactor burst techniques on the Sandia Pulsed Reactor SPR II.

A Type I …

The Dynamic Pressure Distribution And Rigid Body Response Of A Small Buried Dome Subjected To An Airblast-Induced Loading., Richard Cramond

Civil Engineering ETDs

A 9 inch in diameter rigid hemispherical dome was buried in the bottomless soil bins of a vertical shock tube. The interior diameter of the soil bins was 22-3/4 inches, with the interior wall being covered with a friction reducing membrane. An airblast was generated so as to strike the soil perpendicular to the soil surface. The peak reflected pressure of this airblast averaged 315 psi throughout the fourteen tests with the dome. Instrumentation measured the air pressures at the soil surface, the free-field soil stress above and below the dome, the radial on-structure stress on the dome, the rigid …

Runoff And Sediment Studies For San Pedro Creek, Sandoval, Bernalillo, And Santa Fe Counties, New Mexico, Elvidio Olavo Vidalito Bernado Diniz

Civil Engineering ETDs

The San Pedro Creek basin has a drainage area of 195 square miles stretching from the eastern slopes of the Sandia Mountains to the Rio Grande in the northwest. The lower elevations in the basin have a typical semiarid climate, but the higher elevations are more humid. The basin is disected by dendritic patterned drainage systems; approximately twenty-two of these systems compose the basin. The area is a woodland with juniper, pinon, and grasses prevalent. The geology of the area is very complex numerous faults occur within the basin, and three major faults border it. The soils in the basin, …

Test 1042: Oliver 1655, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.

Test 1040: Oliver 1855 Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.

Test 1041: Oliver 1655 Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.

Electronic Analog Computer Hydrologic Simulation Of The Upper Bear River Basin, Mohammed A. Basha

All Graduate Plan B and other Reports, Spring 1920 to Spring 2023

OF the total precipitation falling on watersheds throughout the world, an average of approximately 85 percent returns directly to the atmosphere through evaporation and use by mountain vegetation. The remaining 15 percent moves from the watersheds as runoff and becomes available in the valleys to be used by man for irrigation, industry, recreation, and many other requirements in recent years has led to an increasing need for efficient management of available water resources, and in this regard computer modeling or simulation has proved to be a powerful tool.

The study described herein involves simulation of the hydrologic system of the …

A Study Of Flooded And Rain Infiltration Relations With Surface Ponding, Yehia Z. El-Shafei

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The non-linear partial differential equation (combination of Darcy's law and continuity equation) has been used in this investigation to predict the flooded infiltration through soils possessing appreciable amount of clay and initially drier than its field capacity. One of the most important assumptions made in solving the differential equation is that the capillary conductivity-moisture content relationship is unique for each initial moisture content computation due to the different reaction of clay minerals with different initial moisture contents.

Mathematical equations were also derived to predict:

1. The rate of the wetting front advance, prior to the occurrence of surface ponding, taking into …

Irrigation Water Management Potential In The Bear River Delta, Tom Al Austin

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The purposes of this study were to evaluate the present irrigation efficiencies of the Bear River delta area of northern Utah and to propose a set of management proposals to improve the irrigation efficiency. In order to evaluate the present use, all pertinent data on the water resources of the Bear River delta had to be assembled and analyzed.

A hydrologic budget is a method used to account for all inflows, outflows, and changes in storage within a given area. In this study, all inflows and changes in storage were evaluated and the outflow was predicted. In this manner the …

A Study Of An Unintentional Shutdown (Scram) Problem In The Operation Of The High Flux Isotope Reactor, Cheng Ping Wu

All Graduate Plan B and other Reports, Spring 1920 to Spring 2023

The High Flux Isotope Reactor (HFIR) at the Oak Ridge National Laboratory experiences occasional operating difficulties caused by temporary low voltage conditions on its main power feeder line. The low voltage causes the shutdown of one or more of the three primary coolant pumps. When two of these pumps are shut down, the capacity of the cooling system is reduced to the point where the reactor is scrammed due to a high inlet coolant temperature.

This study was made to determine the cause of the high inlet temperature when operating with one primary coolant pump and to suggest possible changes …

Estimating The Rainfall-Runoff Characteristics Of Selected Small Utah Watersheds, Clive H. Walker

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Runoff and rainfall data have been taken from three high mountain Utah watersheds and subjected to runoff to rainfall comparisons. The resulting Q/P ratios have been compared to the average volumes of runoff curve numbers (CN) computed from this data for each watershed. Runoff curve numbers were also estimated on the basis of the soils and vegetation data available for the watersheds.

An attempt has been made to estimate the watershed lag characteristics by computing synthetic hydrographs for successively larger values of time to peak estimates until the best fit comparison was achieved between the snythetic and the actual hydrographs. …

A Study Of The Secant Law For Sporadic E, Ruey-Yuan Han

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The secant law is the relationship between the frequencies of a vertically incident wave and an obliquely incident wave that are reflected from the same level (i.e., density) of a stratified ionosphere. This thesis investigates the validity of the secant law applied to sporadic E.

Sporadic E data from two backscatter sounders and one vertical incidence ionosonde located in Japan were studied to test the validity of the secant law. The B-scan photos of the backscatter sounders were searched for E_s patches which were then compared with the sporadic E parameters defined for vertical incidence ionograms.

Finally, two theoretical …