Digital Commons Network^™

Mechanism Of Siliconizing Of Molybdenum And Tantalum By Vapor Deposition, Gordon Pu Kong Chu

Doctoral Dissertations

"Molybdenum and tantalum were siliconized in an enclosed system by the hydrogen reduction of silicon tetrachloride with induction heating between 900°C and 1450°C.

The siliconizing process was primarily influenced by the gaseous composition, temperature, time, molar flow ratio (SiCl₄/H₂), geometrical shape and ionization charges. The rate of siliconizing, measured as the weight gain by the fused quartz helix balance, generally follows a parabolic law, y = k t^1/2, where y = weight gain, t = time, and k = rate constant. The activation energy is estimated at 21.6 k cal/mole for siliconizing of molybdenum. …

Petrology And Mineralogy Of Certain Portions Of The Fredericktown Deposits, Farouk El Baz

Doctoral Dissertations

"The Fredericktown area is part of the 'Lead Belt' district of southeastern Missouri, the major lead-producing region in the world for fifty years. The district is a typical example of the Mississippi Valley Type deposits. The ores occur in Upper Cambrian sediments overlying Precambrian rocks.

The Fe-Cu-Pb-Zn (-Co-Ni) - sulphide deposits of Fredericktown occur over a few square kilometers in sediments overlying two 'granite knobs'. The sedimentary units lap upon and pinch-out against these buried basement hills.

The basal sedimentary unit, the Lamotte Formation, is a time-transgressive, marine, submature orthoquartzite. It contains a Boulder Bed at the base or at …

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 …

Lattice Parameters, Thermal Expansion Coefficients, Densities, And Imperfections In Silver And In The Alpha-Phase Of The Silver-Indium System, Samir Moustafa Riad

Doctoral Dissertations

“An investigation of structure insensitive properties (lattice parameters, thermal expansion coefficients, densities, and imperfections) of silver and the α-phase of the silver-indium system was suggested by the desirable uses for silver and its indium alloys.

Both silver and indium used were 99.999 per cent pure. The silver-indium alloys were prepared by melting both metals inside evacuated and sealed fused quartz tubes. The solidified alloys were annealed and then examined by X-ray diffraction for homogeneity.

This experimental work is divided into three main parts:-

I. X-ray diffraction investigation to determine the solid solubility limit of the Ag-In α-phase at 25° C, …

Stratigraphy Sedimentation And Petroleum Possibilities Of The Middle Ordovician (Kimmswick-Galena) Rocks Of Missouri, Illinois And Iowa, Krishna Kant Misra

Doctoral Dissertations

"Detailed surface and subsurface studies of the Kimmswick Limestone and the Galena Formation of Middle Ordovician age in eastern Missouri, western Illinois, and southeastern Iowa were conducted in order to examine their stratigraphic relations, geological history, environment of deposition, and petroleum possibilities.

The main objective of this study was to seek a stratigraphic subdivision of the Kimmswick Limestone in Missouri, based on its gross lithology and thin section study, and its correlation with the Galena Formation in Illinois and Iowa. As a result of this study, based on the examination of twelve surface sections and 92 thin sections a three-fold …

A New Determination Of The Homogeneous Nucleation Rate Of Water In Helium, Edward Francis Allard

Doctoral Dissertations

"The object of this investigation is to apply the best known cloud chamber techniques to the study of condensation phenomena, directed mainly toward the development of a precise method for the determination of homogeneous nucleation rates. A secondary object is to investigate the properties of re-evaporation nuclei so that adequate precautions may be taken to eliminate their detrimental effect in the homogeneous nucleation experiments"--Statement of Problem, page 10.

On The Kirkwood Superposition Approximation, Russell V. Cochran Jr.

Doctoral Dissertations

"When the Kirkwood superposition approximation for the triplet distribution function is used in the Born-Green equation for the pair distribution function of a liquid, the fourth virial coefficient is given incorrectly. In view of this, two suggestions for improving the approximation have been investigated. A suggestion, due to G.H.A. Cole, that better results could be obtained by using a second-order integro-differential equation of the Born-Green type with the superposition approximation used for both the triplet and quadruplet distribution functions has been investigated, and results for a hard-sphere model show that this method gives considerably less reliable results than those obtained …

The Gamma Radiolysis Of Aqueous Stannous-Chloride - Hydrochloric Acid Solutions, Richard Calder Hatch

Doctoral Dissertations

No abstract provided.

The Life History Of The Round Whitefish, Prosopium Cylindraceum (Pallas) Of Newfound Lake, New Hampshire, Donald Arthur Normandeau

Doctoral Dissertations

No abstract provided.

The Gamma Radiolysis Of Ammonia And The Methylamines In The Gas Phase, Robert Carl Schiek

Doctoral Dissertations

No abstract provided.

Mineralogy, Petrography, And Ceramic Properties Of Lower Cabaniss Underclays In Western Missouri, Anthony C. Tennissen

Doctoral Dissertations

The mineral and chemical components, the petrography, and the ceramic properties of the Weir-Pittsburg, Tebo, and Mineral underclays In Barton, Vernon, St. Clair, sod Henry Counties of western Missouri have bean Investigated by x-ray diffraction, differential thermal, spectrographic, microscopic, and certain ceramic testing techniques. The underclays are composed principally of little, kaolinite, end mixed-layer illite-montmorillonite. Illite is the dominant mineral. The principal non-phyllosilicate minerals are quarts sad pyrite. The under clays are mineralogically similar to the underlying shales and contain clay pallets which also are mineralogically similar to the underclays and shales in which they are found. The clay appears …

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 …

An Investigation Of The Deformation Textures Of Cobalt, Roy Carl Wilcox

Doctoral Dissertations

"Deformation textures of various cobalt structures as a result of cold rolling together with some annealing textures were studied. The textures of cobalt were determined using a modification of the Schulz-Decker Geiger counter technique. Pole figures of the (1011), (0001) and (1010) planes were constructed. Also, a study of the microhardness of cobalt was made.

Microhardness tests were performed on various cobalt structures, in both the cold rolled and unworked conditions. The microhardness was found to vary with the source of the cobalt, the crystal orientation, and the amount of deformation and twinning. Deformation lines about the hardness impressions diffused …

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 …

Statistical Analysis Of Fracture Stresses Of Triaxial Porcelain Bodies, Robert E. Moore

Doctoral Dissertations

"Triaxial porcelain bodies containing various forms of silica, quartz, cristobalite and fused silica, were strength tested in bending. Significance tests were employed to discern real differences in the strength sample statistics caused by the various forms of silica. Firings were performed at three temperature levels. The differences in strength sample statistics were correlated to the microstructures of these silica porcelains.

A triaxial alumina porcelain body was employed as a model brittle solid for a study of the effect of flaw density on mean fracture stress. The flaws were introduced in the form of large diameter (d̄ = 115 microns) rounded …

Mineral Paragenesis And Trace Element Distribution In The Tri-State Zinc-Lead District Missouri, Kansas, Oklahoma, Richard D. Hagni

Doctoral Dissertations

"A review of the literature pertaining to the mineral paragenesis and trace element distribution in the Tri-State zinc-lead district of Missouri, Kansas, and Oklahoma revealed inconsistencies in observation and in interpretation and divergent hypotheses regarding the origin of the ores. In an attempt to reconcile the data collected by many investigators over nearly three-quarters of a century, the writer observed working faces in 37 mines, collected over 2,000 specimens for binocular examination and prepared and studied 110 polished surfaces and 60 thin sections of the ores and associated rocks utilizing mineralographic, petrographic, and x-ray techniques. This detailed study resulted in …

The Geology Of The Eldorado Mining District, Clark County, Nevada, Spenst M. Hansen

Doctoral Dissertations

The rocks of the Eldorado mining district, Clark County, Nevada, are of Precambrian, Tertiary and Quaternary age. Precambrian rocks include a heterogeneous series of gneisses and schists, younger garnetiferous granite gneiss and a youngest group of pegmatites. Paleozoic and Mesozoic rocks present in surrounding areas are absent in the district and Tertiary volcanics lie directly on the Pre- cambrian basement. Tertiary rocks consist of middle to late Tertiary flows and pyroclastic beds of andesite, basalt and rhyolite. These are assigned to three volcanic formations: the Patsy Mine volcanics; the Golden Door volcanics; and the Mount Davis volcanics. The Patsy Mine …

Coordination Chemistry Of Piperazine And Piperazine Derivatives, Frederick Woods Obear

Doctoral Dissertations

No abstract provided.

A Kinetic Study Of The Gas Phase Reactions Between Nitrogen-Pentoxide Andsome Reducing Agents, Robert William Ricci

Doctoral Dissertations

No abstract provided.

Kinetics And Mechanism Of The Protonolysis Of The Tin-Hydrogen Bond, Philip Leo Levins

Doctoral Dissertations

No abstract provided.

Studies On The Inhibition Of Tobacco Mosaic Virus Infection By Plant Juices, Growth Regulators, And Systemic Insecticides, Victor Weeraratne

Doctoral Dissertations

No abstract provided.

Interrelationships Of Copper, Molybdenum And Sulfate Sulfur In Bovine Nutrition, John Edward Vanderveen

Doctoral Dissertations

No abstract provided.

The Radiation Induced Exchange Of Carbon Between Ethane And Methyl Amine, Philip Shepard Lamprey

Doctoral Dissertations

No abstract provided.

Sorption And Diffusion In Polyvinyl Acetate And Other Linear Amorphous Polymers, Roger Peabody Kambour

Doctoral Dissertations

No abstract provided.

Some Physical, Chemical, And Thermohydrodynamic Parameters Of Explosive Ammonium Nitrate-Fuel Oil Mixtures, Joseph J. Yancik

Doctoral Dissertations

"The explosive properties of ammonium nitrate-fuel blasting agents were investigated by measuring their detonation velocity and sensitivity. Detonation velocity was measured by a pin oscillograph method with a modified pin technique. Five types of tests were used to evaluate the explosive sensitivity of AN-fuel mixtures under varied environmental conditions. These tests measured the confined and unconfined critical diameter, minimum primer for a three inch diameter iron pipe confined charge, for an unconfined charge at the critical diameter, and minimum primacord primer under special conditions.

Properties of ammonium nitrate-fuel blasting agents were evaluated by considering the effects which each component of …

Polarographic Studies Of Some Organo-Tin Compounds In Anhydrous (N,N)-Dimethylformamide, Roger Baker Allen

Doctoral Dissertations

No abstract provided.

A Molecular Orbital Treatment Of Chemical Reactivity, M Donald Jordan Jr.

Doctoral Dissertations

No abstract provided.

Imperfections Within Ti₂O₃ And Tio₂ Phases In The Titanium-Oxygen System, Tatsuhiko Ejima

Doctoral Dissertations

“The hexagonal-rhombohedral Ti₂O₃ phase in the Ti-O system extends from 32.5 to 34.5% oxygen b.w., with the exact composition of Ti₂O₃ nearly in the middle of the phase. Seven samples of different composition within that phase were made, and the lattice constants (a and c) and the density of each sample were determined.

The plots of the constants against the composition of the samples revealed a deviation from Vegard’s rule when approaching the exact composition of Ti₂O₃. The lattice constants of this compound, obtained by graphical interpolation were; a_{25 …}

Reactions Of 1-Methyl-4-Halo-4-Piperidyl Phenyl Ketone And Derivatives, Henry Joseph Troscianiec

Doctoral Dissertations

No abstract provided.

Geometrical Enantiomorphic Isomerism, Gloria Gilbert Lyle

Doctoral Dissertations

No abstract provided.