Engineering Commons^™

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, …

Response Of Orthotropic Bridge Decks To Highway Loadings, Harry Morris Rexin

Dissertations and Theses

This thesis documents the fabrication, testing techniques, and response of a plastic scale model of an orthotropic bridge deck. To economically investigate a two-lane steel bridge deck, plastic Acrylic^R was used as a modeling material. Welds were simulated with dichloromethane, a capillary action solvent, and PS-30, a polymerizable cement. Deflections were measured with laboratory dial guages while strains were monitored with strain guages mounted on the deck.

The response of the deck to AASHO vehicle axle loads was compared with a discrete element computer program used to analyze orthotropic bridge decks continuous over flexible supports. Results indicate good correlation …

Effects Of High Altitude Jet Aircraft On The Stratosphere, Dennis K. Bushnell

Retrospective Theses and Dissertations

This paper presents a review of the basic thermal, chemical and radiation balances existing in the atmosphere and discusses the mechanisms by which jet engine exhaust products can disturb these balances. Possible effects of stratospheric pollution on plant and animal life are discussed. Methods for reducing harmful emissions through engine design modifications are outlined and current successful research programs are surveyed. The SST type aircraft is shown to be a greater threat to the environment than conventional jets because of differences in cruise altitudes. It is concluded that due to the existence of several potential environmental problems associated with contamination …

Remote Sensing Of Earth Resources System Capabilities V.S. Design Constraints, William Howard Grisham

Retrospective Theses and Dissertations

There is new evidence that global earth resources satellite net will be practical. This paper weighs recent advances in remote sensing to pinpoint the dominant constraints. The data and sensor systems interfacing requirements are critically reviewed. It is shown that conventional optics constraints can be relaxed, with the newer systems, based on multi-spectral imagery and statistical processing methods. The most powerful computational methods use algorithms based on a Gaussian assumption for the species vector in feature space, but biases in the imagery limit their efficiency. A rationale is proposed: improving the observational network calibrating efficiency will also improve the photogrammetric …

Computer-Aided Design Of Light Aircraft To Meet Certain Aerodynamic And Structural Requirements, Joanne Lynn Walsh

Mechanical & Aerospace Engineering Theses & Dissertations

Nonlinear mathematical programming techniques are applied to a particular aircraft design problem, that of determining the maximum range design for light aircraft subject to certain aerodynamic and structural requirements. Search techniques available in an existing nonlinear optimization computer program, AESOP, are applied to the design problem. Seven design variables are used to define the wing dimensions, the wing skin thickness, the cruise velocity, the amount of fuel carried, and the engine horsepower. The influence of different design requirements on the range is observed and discussed.

An Investigation Of A Free Jet At Low Reynolds Numbers, George C. Greene

Mechanical & Aerospace Engineering Theses & Dissertations

This thesis presents a comparison of the measured and calculated flow field properties of a nozzle of unusual design which was used to produce an incompressible, low Reynolds number ]et. The "nozzle" is essentially a porous metal plate which covers the end. of a pipe. Results are presented for nozzle Reynolds numbers from 50 to 1000 with velocities of 100 or 200 ft/sec. The nozzle produces s, uniform velocity profile at nozzle Reynolds numbers well below those at, which conventional contoured nozzles are completely filled with the boundary layer. A Jet mixing analysis based on the boundary layer equations accurately …

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 …

A Simulation Modeling Approach To Central City Dynamics, Leonard William Schaper Jr.

Dissertations

This dissertation describes a computer simulation model of a central city with emphasis on its application to Newark, New Jersey. The work begins with a review of the Forrester Urban Dynamics Model; the first attempt to simulate the entire system of the city. The objections to this model which have appeared in the literature are discussed, and the model is viewed in the light of other work in the field. A set of guidelines to aid the "second generation" model building effort is developed. The actual construction of a model which attempts to follow these guidelines is described. First, the …

Representation And Characterization Of Thixotropic Fluids, Huei-Hsiung Wang

Dissertations

Thixotropy is a time-dependent rheological behavior of a group of fluids which are characterized by an isothermal reversible breakdown induced by a mechanical disturbance. Based on this definition, a mathematical model of reversible degradation kinetics is set up. Its development leads to two equations which represent quantitatively the hysteresis loop and torque-decay curve. These equations consist of five independent parameters with their physical meanings. These parameters can be used to characterize the properties of thixotropic materials.

The original Weissenberg Rheogoniometer was modified to measure the thixotropic behavior of blood with the step change and the ramboid change of shear rate. …

The Effect Of Ultrasonic Vibrations On Heterogeneous Catalysis, William Lintner

Dissertations

The effect of ultrasonic vibrations on the vapor phase decomposition of cumene to benzene and propylene was investigated employing silica-aluminum cracking catalyst.

The catalytic reactor consisted of a 1 cm. diameter stainless steel tube containing a 20 in. long preheater and a 4 in. long catalyst chamber. The catalyst bed was irradiated from above by means of an ultrasonic horn which transmitted acoustical energy directly into the vapor.

The reactor was run at temperatures of 650°F. and 1050°F., frequencies of 26,000 cps and 39,000 cps, feed rates of 20 to 600 gms./hr., power outputs of 0.5 to 1.3 watts/cm.^{2 …}

The Photolysis Of Chlorobenzene In An Aqueous Environment, Louis John Del Tufo

Theses

Chlorobenzene was chosen as a model system for the study of photochemically induced reactions in an aqueous environment. It was the goal of this research to achieve a reaction system which best approximates conditions existing in the environment. To do this, a basic model system was established, and then the effect on the rate by various parameters was studied. These parameters, which included the presence of oxygen and such inorganic compounds as might be present in receiving waters, (e.g. nitrate, sulfate, and phosphate), were chosen so as to meet the goal of this research.

Kinetic data was obtained for seven …

Distillation Design Techniques, Ronald Michael Carlucci

Theses

A design method for binary distillation systems is presented that minimizes the required rigorous calculations. A computer program is developed that finds the number of theoretical stages, and feed stage for a specified separation and reboiler vapor rate. Results for three binary systems are presented.

The design method and computer program are extended to the multicomponent case at the condition of total reflux. Results for one ternary system are presented. The possibility of using the method at other than total reflux is discussed. Usage of the method to search for multicomponent azeotropes and results are also presented.

Analytic equations are …

The Quantitative Characterization Of Middle Distillate Fuels For Reduced Smoke Emission And Improved Low Temperature Operability, R. S. Feamster

Theses

Forty-eight inference equations are presented to approximate the hydrocarbon composition of middle distillate fuels and of the solids separating from these fuels at temperatures below their cloud points by consideration of fuel physical inspections. The physical inspections consist of API gravity, aniline point, cloud point, and distillation curves for ten fuels from major United States and European refineries. To determine the percentage of solids separating from cooled fuels, each fuel is filtered over a temperature range from the cloud point to -40 F in 10 F increments. Aromatic, naphthenic, and paraffinic hydrocarbon contents and the r-paraffin carbon number distributions of …

Antoine Type Equation For Liquid Viscosity Correlations, Edward Goletz Jr.

Theses

A modified Andrade⁴ equation, similar to the Antoine equation for vapor pressure-temperature correlations, was developed for liquid viscosity-temperature correlations. Included in the investigation were the following compounds: n-alkanes (C₂-C₂₀), n-alkenes (C₂-C₂₀), n-alkyl benzenes (C₆-C₁₀), n-alkyl cyclohexanes (C₆-C₂₂), and fifteen polar compounds. Except for propene, errors of less than 5% were obtained. Normal heptadecane was used to compare correlations developed by Andrade⁴, Walther²⁰, and Doolittle⁹, with the modified Andrade equation. The latter was found to give the best …

Stress-Relaxation Of Cross-Linked Polyethylene At Elevated Temperature, Ravio Luik

Theses

Polyethylene because of its excellent chemical, physical, mechanical and electrical properties, as well as its easy adaptability to extrusion, molding and other processes and its low cost has become a very widely used material for hundreds of applications. But, because it is a thermoplastic, it also deforms and flows when temperatures approach or exceed the crystalline melting point. This handicap, however, can be reduced by crosslinking the polymer chains and thereby converting the thermoplastic to a thermoset material. To further expand the possible uses of this popular material and to further improve the properties, fillers and antioxidants may be compounded …

A Computer Solution For Absorbers And Strippers Using The Newton-Raphson Iterative Method, Robert J. Lukach

Theses

The solution of absorber or stripper calculations by traditional methods can be a tedious, time consuming, if not a completely fruitless procedure. Hence a computer solution of these calculations is both desirable and, as the complexity of chemical process plants increases, necessary.

The component oriented Newton-Raphson procedure was programed to perform this calculation, and makes full use of the material and enthalpy balance equations to perform the iterative equilibrium stage calculations. A Newton-Raphson stage oriented method was also developed as a verification program to check the solutions obtained from the Newton-Raphson component oriented procedure.

Computer Simulation Of A Split Feed Claus Sulfur Recovery Plant, Thomas R. Woolley

Theses

A computer program which calculates a complete heat and material balance around a "split feed" Claus sulfur recovery plant was written in Fortran IV for the RCA Spectra 70 computer. The program provides for up to three catalytic reactors, the hot gas bypass method of reheating, and a feed gas containing hydrogen sulfide, water vapor, hydrogen, and nitrogen. The program user specifies as input data the feed stream composition and temperature, the number of reactors, the combustion air temperature, the conversion in each reactor, the outlet temperature in each condenser, and the fraction of burner exit gas used for reheating …

A Theoretical Study Of Continuous Parametric Pumping At Constant Temperature, Philip Weingartner

Theses

A continuous parametric pump, operating at constant temperature with pressure as the driving force, is analyized by means of an equilibrium theory. A thorough explanation of the process and the resulting mathematical model reveal how the parameters effect pump performance. The experimental data cited agree well with the analytical results in the CO₂-He on silica gel system. Complete removal of the solute from one of the product streams can be achieved through the proper selection of penetration distances and pressure levels.

Interfacial Energy And Wettability Of Some Glass-Metal Systems, Mahmoud Yehia Demeri

Archived Theses and Dissertations

No abstract provided.

The Theoretical Distribution Of Forces In The Rigid Component Of The Buccal Arch Positioner, Dennis H. Teruya

Loma Linda University Electronic Theses, Dissertations & Projects

The distribution of an applied force to the rigid component of the Buccal Arch Positioner was determined with a theoretically formulated model. The rigid component was assumed to be a free body without the semi-rigid attachments and was evaluated at four points for the force distribution. The summation of the forces and the moments were equated to zero and were utilized to derive equations to solve for the unknown forces. The unknown forces at each point of the rigid component were solved for in terms of the given force applications.

A laterally directed force application at one of the posterior …

A Method Of Analyzing Mandibular Movement, Richard B. Mccoy

Loma Linda University Electronic Theses, Dissertations & Projects

Mandibular movement is considered to be a fundamental factor in the study, analysis, and treatment of occlusion. For many years, dentists have realized that dental health depends upon the compatibility of mandibular movements and occlusion. This realization has led to the development of new methods and techniques for recording accurately and scientifically the movements of the mandible. In order for this data to be of scientific value, it must be stored in a usable form which is easily available for analysis.

The purpose of this research project was to develop a procedure for storing and recalling mandibular-movement information. Before such …

A Study Into The Feasibility Of Constructing A Pedestrian Mall In Newark Downtown, Stephen Wesley Warren

Theses

Newark's central business district has been suffering steady economic decline for at least a decade. In an attempt to halt this trend, and perhaps even reverse it, a feasibility study has been conducted toward the goal of implementing a pedestrian mall in the area.

This study was accomplished by conducting both field examinations of Halsey Street, the area under consideration, and investigating data from other existing United States pedestrian malls.

The results of this study show that it is feasible to construct a permanent pedestrian mall on Halsey Street and that the benefits of doing so far outweigh the costs …

Separation Of Glucose - Fructose - Water Systems Via Thermal Parametric Pumping, Zikri Mostafa Ahmed

Theses

Series of experiments were carried out to determine the effect of different factors on adsorption from aqueous solutions of sugar using fuller's earth ( LW 16-30 Mesh ) as an adsorbent. The equilibrium data were fitted to the Langmuir's equation., and an explanation for the deviation of some of these data has been given.

Systems of glucose-fructose and water mixtures were subjected to semi-continuous and continuous parametric pumping operations using activated carbon (400 Filterasorb) as an adsorbent. The results obtained confirm the equilibrium theory of the parametric pump and essentially fulfill the requirements established by Chen and Hill (6) to …

Diffusion Studies With Novel Plastics, Marion Toohey Conway

Theses

The rates of diffusion through two fluorinated groups and two non-fluorinated groups of laboratory prepared membranes were compared with each other and with commercially available cellulose membranes. The membranes.were evaluated, in particular, for possible use with the artificial kidney. Diffusion experiments were conducted with sodium chloride, urea and uric acid. Experimental results were compared to diffusion coefficients calculated in the literature for cellulose membranes. The results show that the rates of diffusion of all of the solutes tested for the laboratory prepared membranes are comparable to that of the cellulose membranes. The fluorinated group had a slightly higher diffusion coefficient …

Minimum Reflux In Fractionating Columns : A New And Improved Short-Cut Method, Elizabeth Garcia

Theses

A short-cut method is presented for calculating the minimum, reflux rate for multicomponent systems. This new method is best suited for use on the computer and gives a very accurate estimate of this important factor in the design of fractionating columns. It does so without going to the tedious and time-consuming calculations of the rigorous methods.

The calculation approach is based on a simplification of the Thiele and Geddes method for fractionating columns under minimum reflux conditions.

The program is written in Fortran IV language and was used on an IBM 370 computer. Input specifications include the split of the …

Kinetic Modeling Study Of Catalytic Hydrogenation Of Codimer, William Mounce

Theses

A kinetic modeling study was made on a gas phase catalytic reaction. The data used was that on the hydrogenation of codimer, collected by Tschernitz, et al, The objective was to determine if non-linear least squares regression offers an advantage over linear least squares regression in discriminating between Langmuir. Hinshelwood kinetic equations.

For the experimental data in question, it was found that neither linear nor non-linear regression could distinguish between the two plausible mechanisms. With the particular mechanistic equations and range of data used in this study, the more laborious non-linear analysis offered no advantage over linear regression in discriminating …

An Analysis Of The Geneva Mechanism As A Timing Device, Hubert W. Meyer

Theses

A mathematical analysis of the Geneva mechanism was conducted to determine the potential of this device as a tinting mechanism, and the feasibility of replacing the widely used pallet and starwheel escapement with a Geneva mechanism.

The primary objective of the study was to determine if the Geneva mechanism will attain a terminal velocity, and if so, how much time is required to reach this velocity.

To accomplish this objective, the differential equation of motion for the system was derived using Lagrangian dynatos. The equation was programmed and solved on a digital computer.

The study indicated that the Geneva mechanism …

Aboveground Fuel Oil Storage Tanks, Lawrence George Palmer

Theses

A review of the American Petroleum Institute Standard 650 and Appendixes points out the advantages of using high strength steel and the variable point design method (Appendix K) to obtain reasonably uniform shell stresses. Design limitations imposed by notch toughness and residual stresses are pointed out.

Design considerations for the installation of an internal floating roof in a standard cone roof tank are discussed. Methods of calculating evaporation losses and an economic justification for a floating roof are included. Budget estimate figures have been compiled as a function of tank capacity for tanks, site preparation and tank ringwall or piled …

Sidestream Tower Fractionation : A Short-Cut Calculation Method, Richard David Prickett

Theses

A short-cut procedure has been developed for making calculations on a complex fractionation tower. A Simplification of the Thiele-Geddes plate-to-plate procedure provided the basis for the short-cut procedure. The application discussed in this paper is for a tower with a liquid sidestream drawoff in the rectifying section.

The tower was broken at the feed point and sidestream drawoff locations into three calculation sections. The fractionation in each tower section can then be represented by a rigorous series solution expressed in terms of absorption or stripping factors. These rigorous equations can then be simplified by the use of average absorption or …