Engineering Commons^™

Relationships Among The Metallurgical Condition, Hardness, And The Electrical Conductivity Of Aluminum Alloys, Richard A. Mueller

Masters Theses

"Electrical conductivity measurements (eddy current determined) combined with indentation hardness measurements are now being used throughout the aerospace industry for nondestructive evaluation of the metallurgical condition of commercial precipitation hardenable aluminum alloys. The review of literature and experiments with two aluminum alloys, 7178 and a 5% Zn-Al binary, have shown that skilled interpretation of hardness-conductivity data depends not only upon a qualitative understanding of the modern wave mechanical theories of electron conduction, but also upon some knowledge of the precipitation reaction kinetics. In particular, the effects of "quenched-in" vacancies and retrogression upon the reaction kinetics must be considered. Studies of …

Effects Of Mixing Procedure Upon Uniformity Of Fibre Reinforced Concrete, Donald E. Nortrup

Masters Theses

"This thesis describes the effects of several methods of introducing wire fibres into a concrete mix upon the uniformity of wire fibre reinforced concrete. Various mechanical and manual methods of introducing the fibres were used and comparisons of the methods were based upon variability in splitting tensile strength and the quantitative distribution of the fibres as determined by visual inspection of sawed cylinders. Test results show that the tensile strength of concrete is increased appreciably by the inclusion of steel wire fibres in the mix and the uniformity of strength is similar to that of unreinforced concrete. The methods of …

An Investigation Of The Effects Of An Impact On Some Of The Mechanical Properties Of Aluminum Alloy 2014-T6, Rajnikant K. Shah

Masters Theses

"Static and impact tests were conducted on an Aluminum alloy 2014-T6 specimen. The purpose of this research was to determine the effects of an impact load on some of the mechanical properties of aluminum. The cross section of the specimen measured 4.438 in. by 3.850 in. and it was 12 in. long. It was equipped with a total of four electric resistance gages connected in two pairs. One pair measured longitudinal strain while the other measured transverse strain. Both gages in each pair were mounted on the opposite sides to cancel the bending effect. In the static tests, load was …

The Economics And Design Of Desalination By Evaporation Through Porous, Water-Repellent Membranes, Kuei-Hsiung Yang

Masters Theses

"The economics of desalination by evaporation through porous, water-repellent membranes has been studied in this investigation. Using reasonable assumptions this desalination process was found to be economical with the principal advantage being the simplification of multi-stage flash-type evaporation. Based on this process, two different methods were designed and studied by means of computer calculations for a 10 million gallons product water per stream day desalting plant. One method was based on a membrane evaporator and a heat exchanger and was designated Method I; and a combined evaporation-heat exchanger system was designated at Method II. The major factors affecting the economics …

Convective Heat Transfer In Small Cylindrical Enclosures Heated From Below, Donald Wayne Land

Masters Theses

"Free convection in enclosed air spaces is often of prime importance in the design and analysis of panels utilizing the insulating properties of air and other gases. Previous investigations were performed on very thin air layers.

This thesis presents the results of an experimental investigation to determine the heat transfer by convection and conduction through air layers with relative sizes in terms of length/diameter ratios of one-fourth to one.

Eight cylindrical samples were tested. Four had inside diameters of 2.0 inches, and the others were 2.75 inches in diameter. Heat was transferred across the air layers by both conduction and …

Mode Analysis Of The Unsymmetrically Fed Ground-Plane Aperture, John G. Hemmann

Masters Theses

"The problem of radiation from a waveguide-fed ground-plane aperture perturbed with a wedge-shaped dielectric insert was examined more carefully. The work initiated by Blumberg was continued, using a greater range of dielectric constants and smaller increments of angle.

Aperture field measurements were made over a range of dielectric constants for each wedge angle, in order to determine the change in amplitude distribution as a function of permittivity. Aperture phase measurements were also taken for selected angles. These were used with the amplitude data to predict, using numerical integration, the far-field radiation patterns of the perturbed aperture. Far-field patterns were then …

Study Of Mass Transfer Through Porous Water-Repellent Membrane As A Function Of Membrane Thickness And Rates Of Heating, Yalamanchili Babu Rao

Masters Theses

"The object of this investigation was to study the mass transfer coefficients through porous water-repellent membranes, and their dependence on membrane thickness and rates of heating, and to compare experimental correlations with theoretically based equations. The membranes used during the experimental work were made of glass fiber treated with Teflon suspension and aluminum sulfate. The mechanism involves evaporation and condensation on opposite sides of a vapor-filled porous membrane. Salt water evaporates from one interface of a non-wettable, porous membrane, diffuses through the vapor filled pores, and condenses to fresh water at the other interface of the membrane. This transfer may …

Programmed State Assignment Algorithms For Asynchronous Sequential Machines., Wayne L. Schoeffel

Masters Theses

"An important step in the synthesis procedure for realizing a normal fundamental mode asynchronous sequential circuit is the internal state assignment. Although systematic methods have been developed to construct minimum-transition-time state assignments, they become long and tedious with hand methods for machines with more than 7 or 8 internal states. To extend the application of these algorithms to larger problems, this paper presents an efficient digital computer program for generating minimum-variable state assignments. An alternate program is also presented which, though shorter, does not guarantee a minimum-variable assignment"--Abstract, page ii.

The Relation Of Heat Transfer To Mass Transfer In Vaporization Through Porous Membranes., Chung-Liang Yeh

Masters Theses

"The object of this investigation was to study the mass and heat transport phenomena through porous, water-repellent membranes. The investigation concerned the rate of vaporization of salt water at a porous membrane surface, mass transfer of vapor through the pores of the membrane, condensation of vapor on the other surface of the membrane in contact with a coolant (fresh water), and the undesired heat transfer by conduction through the membrane. The water-repellent membrane separated the two liquid phases by surface tension forces and provided a vapor phase in its pores. Membranes made of fiberglass and Teflon had been found suitable …

A Determination Of The Rate Of Evaporation Of Zinc At Atmospheric Pressure., Yu Ming Su

Masters Theses

"Measurements of evaporation rates of zinc in three different residual gases, e.g., argon, carbon monoxide, and hydrogen at one atmosphere pressure, were made. It was found that the rate of evaporation of zinc in one atmosphere of argon was almost the same as that in carbon monoxide, while the rate in hydrogen was almost twice the rate in argon or carbon monoxide. Measurements of evaporation rate of zinc in one atmosphere of argon-oxygen mixtures were also made. The evaporation rate was considerably reduced because the formation of the oxide film retards the zinc vapor escaping from the evaporating surface"--Abstract, page …

The Design Of A Drum Memory System, Frederick W. Lynch

Masters Theses

"Three methods for obtaining an auxiliary memory for an SCC-650 (Scientific Control Corporation) digital computer are presented. A logic design is then developed on the basis of using the drum and write circuits from an available IBM-650 digital computer and constructing the remaining logic functions. The results of the logic design are the transfer equations necessary to implement the memory system"--Abstract, page ii.

Compressive Creep Of High Alumina Refractories, Vernon Lee Burdick

Masters Theses

"The deformation of refractory materials consisting of 90% sintered or fused alumina plus 10% silica was measured at temperatures from 1450 to 1515⁰C and a compressive stress of 100 psi. Creep rates and activation energies were determined from the steady state portion of deformation vs. time data and correlated with the mineralogical composition. Supplemental measurements included x-ray diffraction, electron probe microanalysis, apparent porosity and tensile strength. conditions having an important effect upon the mineralolgical composition were: (1) duration of heat treatment, (2) amount of sodium oxide impurity, and (3) reactivity of the alumina grain. Prolonged heat treatment and sodium oxide …

A Kinetic Study Of Ti⁺³ Oxidation To Ti⁺⁴ In Hydrofluoric Acid Solutions, Kuo-Shein Shen

Masters Theses

"The purpose of this investigation was to study the oxidation rate of Ti⁺³ to Ti⁺⁴ in hydrofluoric acid solutions in the absence of air. The concentration of hydrofluoric acid was varied from 0.25 to 2.00 M and the concentration of titanium from 0.05 to 0.50 M. The temperature was controlled at 25⁰C. The reaction rate was relatively slow. In most instances, less than 50 percent of the Ti⁺³ was oxidized during a period of 100 hours"--Abstract, page vii.

A Shunt-Feed Antenna System On A Small Supersonic Aircraft, Larry Joseph Nanney

Masters Theses

"A technique was developed which successfully predicted the reactance of a shunt cavity exciting the air frame of a small supersonic aircraft as an antenna. This was possible by the use of the wire above a ground place approximation which closely defined the characteristic impedance of the shunt fed cavity. A correlation was made between the maximum values of parallel resistance of the shunt fed cavity and the length of the air frame or portions of the air frame, which at this point were found to be a quarter wavelength in length. Measurements of the impedance of the shunt-feed system …

A Study Of Film Boiling Of Liquid Nitrogen And Liquid Argon Over A Wide Pressure Range With Cylindrical Heaters, V. J. Flanigan

Masters Theses

""A film boiling heat transfer study was conducted with three different diameter cylindrical copper heaters over a wide range of pressures for nitrogen and argon with the heat transfer surface in the horizontal position. The data were compared to the commonly used film boiling heat transfer relations. The common relations were found to be considerably in error for the range of variables covered in this investigation. A semi-empirical equation for corresponding states fluids which correlates the available data as a function of the reduced temperature and reduced pressure was derived and discussed"--Abstract, page iii.

Analog Simulation Of A Plug Flow Tubular Reactor, Jon Douglas Carson

Masters Theses

"This thesis stresses the importance of analog and digital computers in the field of reaction kinetics. The analog computer is used to simulate a chemical reaction, the hydrolysis of acetic anhydride. The hydrolysis reaction takes place in a tubular reactor. The reactor is 3/4 inch in diameter and 20 feet long. These reactor dimensions allow the reaction system to approach plug flow, if the reactants flow through the reactor at turbulent flow rates. The physical, reactor, system is used to obtain experimental data for the hydrolysis reaction. The data is obtained at reactor temperatures between 75 and 100°F. Feed concentrations …

Construction Of A Laboratory Type, Convertible Excitation Argon Laser, Arthur P. Reckinger

Masters Theses

"The purpose of this thesis is to describe the construction of a general purpose, convertable [sic] excitation, laboratory type, argon laser. Quartz tubing was used in the final model while attempts to use alumina were made during earlier work. The final model has total optical power output of 230 mw at a discharge current of 29 amperes in the dc excitation mode. Provision was also made to utilize RF or pulsed excitation. The device is built so that several values of optical transmittance are available with a wide range of mirror placement"--Abstract, page ii.

Continuous Countercurrent Evaporation Through Porous Water-Repellent Membrane With Pressure Above Atmospheric, Yung C. Hsu

Masters Theses

"An experimental method for measuring mass transfer rates at pressures above atmospheric has been developed for the case of continuous countercurrent evaporation through porous water-repellent membranes. The final developed equipment is suitable for operation under pressures up to 50 psig and at temperatures near the boiling point of 7% salt water when high flow rates are reached. Rates of evaporation of water through the membrane were measured, and the data and results were used to examine the effects of operating conditions on the over-all mass transfer resistance. Least squares equations for fitting the data were also obtained. Over-all mass transfer …

A Transmission Electron Microscopy Study Of Some High Strength Plain Carbon Steels, George Joseph Vytanovych

Masters Theses

"Methods of preparing foils of high strength, heat treated, plain carbon steels for examination in the electron microscope by the transmission technique were perfected and are described. Two processes for the initial thinning of a bulk sample were successful. A chemical process was found to be more rapid but not satisfactory for small samples. A mechanical process was slower, but was applicable to the smaller specimens. Electro-polishing the thinned material yielded acceptable foils from which photomicrographs of good quality were obtained. The microstructure of the high strength steel samples showed typical tempered martensite. No reasons for the differences in ductility …

Stresses In A Thick Spherical Shell, David Wayne Moore

Masters Theses

"This thesis reports a method to evaluate the stresses in a segment of a thick spherical shell. In the numerical examples loads due to thermal expansion as the shell is constrained at the free edge and a dead load acting vertically downward were considered for a shell assumed pinned but free to rotate and for a shell assumed completely fixed at the edge. A concrete shell was specifically studied but the method would also apply to a shell of any homogeneous, isotropic material"--Abstract, page i.

The Realization And Application Of Parallel Linear Feedback Shift Registers, Ross K. Heitzmann

Masters Theses

"Two methods for serial-to-parallel transformation of linear feedback shift registers are briefly discussed. A third method for transformation is rigorously developed using a next-state and output equation representation of the linear feedback shift register. An algorithm is developed for simplifying the parallel machine resulting from serial-to-parallel transformation, where simplification is defined as reduction in the required number of modulo 2 adders. A computer program incorporating serial-to-parallel transformation and the simplification algorithm is provided "--Abstract, page ii.

Characteristic Impedance Of Open Microstrip Transmission Lines Having Finite Thickness And Multiple Dielectric, Philip Julian Carter

Masters Theses

"A computer program is provided for determining the characteristic impedance of microstrip transmission lines having finite thickness. Infinite and finite ground planes are incorporated into the program. The programmer need only supply information in the form of a data card. This procedure is clearly outlined.

Graphical solutions of characteristic impedance for multiple dielectric microstrip transmission line problems are obtained using a discrete resistive analogue. Computer network analysis programs are viewed as having several advantages not possessed by the physical resistive analogue"--Abstract, page 2.

Stress Analysis Of A Wall Footing Subjected To External Vertical Loads And Overturning Moments By The Finite Element Method, Adil Godiwalla

Masters Theses

"This investigation pertains to the stress analysis by the finite element method of a wall footing subjected to external vertical loads and external overturning moments. This problem has been reduced to a two-dimensional stress analysis problem by taking a unit length of the wall. A rectangular plate - element is used throughout this investigation. The development of the matrix equations is shown and the solution is performed by digital computer. Stresses in the horizontal direction show essentially linear variation which is in agreement with simple structural theory, while stresses in the vertical direction show severe perturbation near the column load. …

Computer Solutions To Depletion Drive Hydrocarbon Systems, Tu Kao Chen

Masters Theses

"Three computer analyses of oil production by depletion drive have been developed. These analyses, Tarner's method of depletion drive oil production prediction, depletion drive performance productions of Schilthuis, and depletion drive calculations by a finite difference material balance, have been programmed for computers having Fortran IV compilers and a minimum of 40 K bytes of core storage capacity. Modifications have been incorporated in the last two techniques for (a) constant volume injection of produced gas, (b) the presence of a gas cap, (c) gas-cap injection of produced gas volumes, (d) varying water encroachment and production, and/or, (e) varying sweep efficiencies …

A Study Of Probability Of Error Calculations For Baseband Multi-Level Digital Transmission Systems Using The Fixed Threshold Decision Rule, Don J. Popp

Masters Theses

"This study is an investigation into analytical techniques used in deriving probability of error expressions for baseband multi-level digital transmission systems. A fixed-level decision rule is used to solve this statistical detection problem together with some simple concepts from probability theory. To illustrate these techniques, probability of error expressions are derived for the general uncoded system, a simple coded system, and a complex coded system. Curves of probability of error versus signal-to-noise ratio are plotted for the various systems considered"--Abstract, page ii.

Vapor Pressure And Evaporation Coefficient Of Cadmium Oxide, R. Tom Coyle Jr.

Masters Theses

"Knudsen effusion experiments were carried out on CdO in fused silica crucibles at temperatures of 918°K, 1008°K with orifice areas from 2.742x10^-3 cm² to 30.52x10^-2 cm². The experiments were made in a molybdenum-wire, resistance-heated vacuum furnace. Several orifice areas were used at each temperature and reciprocal pressure versus orifice area plots were made. These plots yielded an upper limit to the evaporation coefficient of. 4.15x10^-2. An equilibrium constant for the vaporization reaction

CdO(s) = Cd(g) + 1/20₂ (g)

of

log Keq = 11.12 - 1.952x10⁴/T.

was obtained. Second and third …

Molecular Diffusion In Polymer Solutions By A Microinterferometric Method, Surendra V. Desai

Masters Theses

"The object of this investigation of molecular diffusion in aqueous polymer solutions was to study the effect of solute concentration on the differential diffusion coefficient and also to study the effect of polymer concentration on the mean integral diffusion coefficient. For this purpose a microinterferometric method was used. Two non-ionic, water soluble polymers, Carboxymethylcellulose (CMC) and Carboxypolymethylene (Carbopol), were used in the study with D-Glucose as a solute.

The differential diffusion coefficient was found to increase with increases in solute concentration in all cases. For CMC, the integral diffusion coefficient at first decreased with increasing polymer concentration but became constant …

The Recovery And Characterization Of Organic Micropollutants From Missouri Subsurface Waters, John Warren Smith

Masters Theses

"The main objectives of this investigation were the recovery and partial characterization of organic micropollutants from Missouri subsurface waters and the evaluation of the number of filters in series required for effective removal of organic materials from water using the Carbon Adsorption Method.

The organics were recovered from a spring and two deep wells using three large capacity (1. 5 cu. ft.) activated carbon filters in series. Chloroform and ethanol were employed as primary elutants, but acetone and benzene were also investigated. Characterization was by organoleptic, chemical, and biological determinations, toxicity measurements, and solubility partitioning.

Organic materials were found in …

Dynamic Response Of A Simply Supported Beam To An Accelerating Point Load, Joseph Victor Cusumano

Masters Theses

"An analysis based on linear theory is presented for determining the dynamic response of a simply supported beam on an elastic foundation acted upon by a moving time dependent point force with axial forces included. This thesis extends the present theory to include an analysis of a point force accelerating uniformly across the beam. In particular, it is shown that the customary resonance conditions which are prevalent for a point force moving with uniform velocity no longer exist for the case of a point force accelerating uniformly across the beam.

The basic problem and its solution are presented for a …

Centrifugal Model Study And Finite Element Analysis Of Stress Near A Fault, Christopher Haycocks

Doctoral Dissertations

"The adverse effects of faults on the stability of underground openings has long been realized. To date, however, discontinuities and most other types of geologic heterogeneities have not been amenable to mathematical analysis using the classical theories of elasticity and plasticity. This investigation examines the stress distribution around a single discontinuity and compares the experimental and numerical methods used for the analysis. The theory of elasticity, employing the equations of compatibility, equilibrium etc., was used to determine a stress function for the stress distribution around a circular hole loaded in a centrifugal field. The analysis was terminated after the stress …