Engineering Commons^™

A Theoretical Approach To The Problem Of Determining Ejecta Volumes In A Gravitational Vacuumed Half-Space, William J. Karwoski

Doctoral Dissertations

"The formation of an explosion crater is a highly complex process. All of the pertinent parameters governing the mechanisms of cratering are not clearly understood or known. Many cratering experiments were performed in desert alluvium in an effort to relate crater dimensions with charge weight and depth of burst. Various scaling laws were devised in an attempt to correlate the data gathered from these experiments. When cube-root scaling was used to correlate results of tests conducted at a constant scaled depth of burst, larger charge weights consistently gave smaller scaled results. This was particularly true of apparent crater volume. When …

Continuously Tapered Dielectric Matching Transitions For Waveguides, William E. Hord

Doctoral Dissertations

"Dielectric matching transitions at microwave frequencies are used for matching air filled waveguides into dielectric filled waveguides for maser work or into dielectric rod antennas. Also dielectric loading has been shown to improve the performance of the ferrite isolators.

The dielectric matching transitions that have been analyzed in the literature are of the stepped type. The continuously tapered dielectric matching transitions investigated in this dissertation provide increased bandwidth with very little increase of physical complexity.

The dissertation provides an analytical method for analysis and design for the continuously tapered dielectric matching transition. First-order and second-order approximate solutions for both symmetrical …

The Anodic Behavior Of Zinc In Aqueous Salt Solutions, Yun-Chung Sun

Doctoral Dissertations

"The increasing demand for protective metals as coatings and non-corrosive alloys has caused extensive research on the fundamental behavior of metals in corrosive media. The problem of controlling the destructive process of metallic corrosion still exists and becomes urgent in this space age. The desirablity of metals such as beryllium, magnesium, and zinc in air frame and space structural units, because of their high strength to weight ratio, has been responsible for the considerable progress in their technology in recent years.

The basic mechanism of the anodic dissolution of metals such as zinc, cadmium, and magnesium in salt solution is …

Aeration Studies In Submerged Fermentations Using A Steam-Sterilizable Dissolved Oxygen Sensor Of Improved Design, Carl J. Wallace

Doctoral Dissertations

"Large-scale submerged fermentations have been important for many years for the production of antibiotics, vitamins, enzymes, etc.; however, aeration studies have been severely restricted in these processes because of the unavailability of adequate oxygen sensing equipment.

A steam-sterilizable oxygen sensor of improved design was developed out of an investigation of several potential sensors. This rapidly responding galvanic probe made use of a lead anode, a silver cathode, an acetate buffer as the electrolyte, and a one mil Teflon® membrane as the diffusion barrier. Its sensitivity was approximately 40 µamps and full response required approximately 5 minutes.

Use was made of …

Hydrogen Absorption And Corrosion Studies Of Zone-Refined Iron, Chang Don Kim

Doctoral Dissertations

"The lattice constants of zone-refined iron filings and iron whiskers are 2.86623 and 2.86626 Å at 25°C respectively. Their thermal expansion coefficients are both the same, 12.1 x 10⁻⁶ /°C at temperatures 10 - 65°C.

The influence of hydrogen on the lattice constant of iron was investigated and it was found that hydrogen has no effect (within the limits of errors) on the lattice constant of iron at room temperature regardless of the charging methods. However, at elevated temperatures hydrogen expands the iron lattice due to increased solubility of the gas. The lattice constant of iron in vacuum and in …

A Study Of The Anodic Oxidation Of Acetylene On Gold Electrodes, Jo Lisle Reed

Doctoral Dissertations

"The object of this investigation was to establish a mechanism for the anodic oxidation of acetylene on gold electrodes in aqueous solutions. It is known that anodic oxidation of organic compounds on gold electrodes produces a large number of organic intermediates and end products. Therefore, it appeared worthwhile to establish a mechanism that could provide a better understanding of the fuel cell electrode kinetics and possibly lead to new methods of organic syntheses"--Introduction, page 2.

Turbulence Measurements In Polymer Solutions Using Hot-Film Anemometry, Gary Kent Patterson

Doctoral Dissertations

"Hot-film anemometry was used to study the detailed structure of turbulence (intensities, energy spectra, and auto-correlations) in Newtonian solvents, non-drag reducing polymer solutions, and drag reducing polymer solutions. This was done in two smooth wall tubes with diameters of 1.0 inch and 2.0 inches. A probe traversing mechanism was used for measurements at radial positions from the center to as near the wall as possible for both the film probes (r/a=0.85 in the 2-inch tube) and the impact tubes (r/ a=0.98). The impact tubes were used to measure velocities for film probe calibration.

The solvents used in this investigation were …

Nonparametric Detection Of Signals Causing Arbitrary Changes In The Accompanying Noise Backgrounds, John Joseph Komo

Doctoral Dissertations

"The detection of signals in the presence of noise is an important problem in the field of communications. The detection problem is concerned with the design of systems which determine only the presence or absence of a signal which occurs with background noise. An example of considerable importance, which is encountered quite frequently in practice, is the radar detection problem. In the radar problem it is desired to determine the presence of a target by detecting the presence of a radar return signal in noise. Another example is the seismic exploration problem which utilizes the detection of reflected signals from …

The Anodic Dissolution Of Cadmium In Aqueous Solutions, San-Cheng Lai

Doctoral Dissertations

"The purpose of this investigation was to study the effect of cadmium ions on the anodic dissolution of cadmium in salt solutions of ·constant ionic strength. The concentration of the cadmium ions was varied from 0.001 to 1 N and the current density ranged from 0.001 to 0.1 amp•cm^-2. The temperature was controlled at 25°C.

....A mathematical model was postulated expressing the anodic dissolution rate as the sum of electrochemical, local corrosion, and disintegration rates."--Abstract, page iii.

An Investigation Of The Induction Heating Characteristics Of Powdered Susceptors Dispersed In A Non-Conducting Medium, Robert Leon Wright

Doctoral Dissertations

"This investigation determined some of the induction heating characteristics of powdered magnetite, iron and ferrosilicon susceptor dispersed in silica sand which had been coated with thermosetting resin. The powdered susceptor particles in the mixture were heated by the field of an induction coil, consequently heating the resin coated sand and bonding the sand grains together.

It was found that the type, relative amount,and particle size of the susceptor were important variables to be considered in the induction heating characteristics. Hysteresis losses in the susceptor particles, which are a function of the coil current, frequency, and permeability, appear to be the …

The Statistical Mechanics Of Kink Interactions, Michael Brewer Mcneil

Doctoral Dissertations

"Using a potential derived from continuum elasticity, the interactions between kinks on a dislocation line are studied as special cases of the problem of a one-dimensional system of interacting particles. By the use of constant pressure ensembles, the principal kink-interaction problems of physical interest are solved. The application of these solutions to the theoretical analyses of work hardening and internal friction is explored and comparisons made to previous work in which kink interactions were neglected; it is found that, as would be expected, variations of equilibrium kink populations with external stress cannot account for the Bordoni peak, which must therefore …

A Study Of The Supercooling Behavior Of High Purity Liquid Bismuth, B. L. Bramfitt

Doctoral Dissertations

"This investigation involves a study of the supercooling behavior of pure bismuth as affected by the melting atmosphere, the amount of superheat, and the intentional addition of metallic and non-metallic foreign materials to the melt. It was found that the amount of oxide on the melt surface is a controlling factor in the degree of supercooling obtainable in bismuth. In the presence of a thick bismuth oxide surface layer the amount of superheat below a 15°C drastically decreases the amount of supercooling due to the retention of nuclei in the surface film that promote nucleation upon cooling of the melt. …