Chemical Engineering Commons^™

The Amino Acid And Monosaccharide Content Of The Cell Walls Of Thiobacillus Thiooxidans, Edward Hibbert Crum

Doctoral Dissertations

"The objectives of this investigation were: (a) to culture large quantities of Thiobacillus thiooxidans cells, (b) to find an acceptable method of rupturing the cells, (c) to find an acceptable method of isolating the cell walls, and (d) to analyze the cell wall components, especially the amino acid and sugar components. The strain of T. thiooxidans used for this investigation was American Type Culture Collection Number 8085. The surface active agents Tergitol 08 and Tween 80 were investigated for their ability to reduce the lag period found in the growth of T. thiooxidans. Although a concentration of 12.5 ppm Tween …

A Structural Investigation Of Bismuth Ferrate And The Bifeo₃-Pbzro₃-Pbtio₃ Ternary System, Gary D. Achenbach

Doctoral Dissertations

"Solid state reaction of Bi₂O₃ · Fe₂O₃ mixtures was shown to yield impure bismuth ferrate, BiFeO₃, containing Bi₂Fe₄O₉ and residual Bi₂O₃; this places the results of much of the literature based on BiFeO₃ prepared by this technique in suspect. Single phase polycrystalline BiFeO₃ was prepared by multiple nitric acid leaching of sintered samples which contained excess Bi₂O₃ to prevent the formation of Bi₂Fe₄O₉ during sintering. X-ray and neutron powder diffraction data indicate that …

A Study Of Surface And Geometric Effects On The Nucleate Boiling Of Liquid Nitrogen And Liquid Argon From Atmospheric To The Critical Pressure, Calvin Benson Cobb

Doctoral Dissertations

"A maximum heat flux correlation was derived for corresponding states liquids and subsequently verified by the data collected in this study as well as data presented in the literature. By applying this correlation, one can predict maximum heat flux values at high pressures from maximum heat flux values measured at low pressures; however, to apply the correlation it is necessary to have at least one maximum heat flux value and the saturation temperature at which it was determined.

Contrary to existing correlations, it is shown that for any nucleate boiling heat transfer correlation to be truly general, it must include …

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 …

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 …

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.

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.

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 …

Drag Reduction In Newtonian Polymer Solutions, Harry C. Hershey

Doctoral Dissertations

"Prior work in the area of drag reduction has been mainly limited to aqueous solutions. Theoretical and empirical analyses of the resulting data in aqueous solutions have been hindered by the fact that some polymers cause drag reduction and others do not...This investigation was directed to the study of how the size and configuration of the polymer molecule in solution affected drag reduction and the related phenomenon of turbulence suppression. Apparatuses were designed and built to measure viscometric flow, curves, friction factors, velocity profiles, and normal stresses (by a jet thrust technique developed by Metzner and associates)"--Summary, page 1-2.

The Microbial Hydrolysis Of Cellulose And Some Factors Affecting The Production Of Cellulase In A Submerged Culture Of Alternaria Sp, Robert Murray Logan

Doctoral Dissertations

"A mile hydrolyzing procedure was utilized to degrade oak sawdust. Its capability of producing a suitable fermentatation [sic] medium was studied. In the interest of solubilizing, enzymatically, the carbohydrate portion of oak sawdust, an investigation was conducted in which various microorganisms were examined for their ability to utilize different forms of cellulose for their growth and to produce cellulose decomposing enzymes. The microorganisms included a myxobacterium, several fungi, and a wood-rotting basidiomycete. The fungi included two highly cellulolytic organisms, Myrothecium verrucaria and Trichoderma viride. The myxobacterium used was Sorangium cellulosum and the basidiomycete was Pleurotus ostreatus. The principla substrates employed …

A Study Of The Eddy Diffusivity In Turbulent Heat Transfer, Frank Fu-Kun Tao

Doctoral Dissertations

"The purpose of this investigation was to determine the eddy thermal diffusivity values as a function of radial position at various Reynolds numbers for a fluid flowing turbulently in a pipe. The ratios of the eddy thermal diffusivity and the eddy viscosity were also investigated.

A vertical column of copper tube two inches in diameter was constructed which consisted of an entrance section for the development of the velocity profile and a heating section for the development of the temperature distribution. The heating section was jacketed and maintained at a constant wall temperature at about 103 ° F by the …

A Study Of Turbulent Mass Transfer In A Wetted-Wall Column, David William Bunch

Doctoral Dissertations

"The field of mass transfer is one of great interest to the chemical engineer. An understanding of this field is vital in the design of many types of chemical processing equipment, particularly in the areas of distillation, extraction, absorption, adsorption, and reactor analysis and design.

However, much of the knowledge in this area at the present time is in the form of empirical relationships, and the basic theory is still not well delineated. This lack of understanding leads to expensive and over-sized or under-sized equipment.

A particular area within this field which needs additional investigation is the theory of mass …

A Study Of The Dissolution Of Titanium-Oxygen-Nitrogen Alloys In Hydrofluoric Acid, Arliss V. Martin

Doctoral Dissertations

"The purpose of this investigation was to study the effect of oxygen and nitrogen (in the alpha solid solution range) on the kinetics and electrochemistry of titanium dissolution in hydrofluoric acid. Dissolution rates, activation energies, difference effects, and potential measurements were determined with TiO_XN_Y sintered alloys and sheet metal. Values of x ranged from 0.01 to 0.126 and values of x. from 0.001 to 0.230.

Dissolution rates were determined using a gas evolution technique. Temperatures were varied from 5 to 45°C. The hydrogen evolution rates were converted to TiO_XN_Y dissolution rates by means of …

A Study Of The Dissolution Of Zr-O Alloys In Hydrofluoric Acid, Wayne Gilbert Custead

Doctoral Dissertations

"The purpose of this investigation was to ascertain and explain, if possible, the effect of oxygen in the metal on the kinetics and electrochemistry of the reaction of zirconium in hydrofluoric acid solutions. This entailed the determination of the effect of oxygen on the dissolution rates, activation energies, dissolution potentials, and difference effect for zirconium in hydrofluoric acid and hydrofluoric-hydrochloric acid mixtures.

The alpha-phase solid solutions of oxygen and zirconium were synthesized by the powder-metallurgy technique. Both the alloy analysis and dissolution rates were obtained by the gas evolution method according to the reaction:

ZrO_x + 4HF → ZrF …

Lattice Parameters, Densities And Imperfections In Indium And Indium-Cadmium Alloys Rich In Indium, Paluri Bhimeswara Rao

Doctoral Dissertations

"An investigation of perfection of the structure of the indium-cadmium system was suggested by the interesting properties of indium and its cadmium alloys. The lattice of indium, though tetragonal, may be considered as distorted cubic, its axial ratio being 1.0767 at 20°C. Furthermore earlier studies have revealed a transformation of the tetragonal structure to cubic in the presence of cadmium.

To determine the perfection or soundness of the indium and indium-cadmium alloys rich in indium, pure indium (99.999 per cent purity) and eight samples of the indium-cadmium alloys ranging in composition from 2.977 to 10.015 per cent by weight of …

A Study Of The Dissolution Of Hafnium In Hydrofluoric Acid, James W. Johnson

Doctoral Dissertations

"The purpose of this investigation was to obtain kinetic and electrochemical information concerning the reaction of hafnium with hydrofluoric acid in order to establish the mechanism of dissolution. This included the determination of dissolution rates, the difference effect, and dissolution potentials of hafnium in hydrofluoric acid"--Abstract, page 1.