Engineering Commons^™

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 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, …

A Thermodynamic Study Of The Zirconium-Sulfur, Titanium-Sulfur And Hafnium-Sulfur Systems In The Disulfide-Trisulfide Region, Norbert Achilles Vermaut

Doctoral Dissertations

"A static method was used to study the equilibria which exist between the higher sulfides of zirconium and sulfur at temperatures from 700° to 1000 °C. Both disulfide and trisulfide have been identified by chemical analysis and X-ray diffraction. There exists a two-phase region of 'ZrS₂' and 'ZrS₃'. The composition limit of the homogeneous disulfide phase appears to exist between ZrS_1.90 and ZrS_2.00. The lower composition limit of the homogeneous region of the trisulfide phase was established as ZrS_2.75.

An experimental method of Blitz and co-workers, i.e., the use of evacuated …

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 …

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 …

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 …

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 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.

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 …

A Thermodynamic Study Of The Zirconium Sulfides, Andrew Hessler Larson

Doctoral Dissertations

"A hydrogen reduction technique was used to determine some thermodynamic properties of various zirconium sulfide phases. The equilibrium H₂S/H₂ ratios were determined as a function of temperature and composition of the condensed sulfide phases. The hydrogen sulfide content of the equilibrated gas mixtures was analyzed by an iodimetric titration procedure.

A detailed description is given for the method and apparatus used both in the preparation of the various sulfide phases and in their equilibration with a hydrogen-hydrogen sulfide gas mixture.

The composition ranger 59 to 67 atomic per cent sulfur was studied over a temperature range of …

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 …}

A Study Of The Recrystallization And The Mechanical Properties Of Indium, Louis John Reitsma Jr.

Doctoral Dissertations

"The recrystallization temperature and the mechanical properties of tensile strength, elongation, reduction in area and hardness were determined for 99.97% indium. Metallographic techniques were developed and stress rupture data were obtained.

Single crystals of indium were grown in a horizontal furnace with a traveling temperature zone, and sectioned in a strain-free manner, with an etch-cutter. Because of the low recrystallization temperature of indium, no further work was done on the single crystals.

The effect of recrystallization on electrical resistance, thermoelectric force, hardness, bending strength, crystallographic orientation and microstructure was studied. The range of recrystallization temperature for small amounts of cold …

A Thermodynamic Study Of The Titanium Sulfides, Reinhard Paul Abendroth

Doctoral Dissertations

"The determination of the thermodynamic properties of chemical compounds is in essence an experimental one. The purpose of this investigation was (1) to make an experimental determination of the thermodynamic properties of the titanium sulfides (2) to determine what sulfide phases are present in the titanium-sulfur system (3) to show the relationships between the various phases present"--The Problem, Statement of the Problem, page 3.

An Experimental And Theoretical Investigation Of The Preferred Orientation In Deformed And Recrystallized Hafnium, David S. Gould

Doctoral Dissertations

"The research problem, as presented, therefore became two-fold; first to investigate and determine the feasibility of fabrication of hafnium and secondly to study the deformation characteristics of the material in light of the overall study of hexagonal metals aimed at the development of an overall general theory of plastic deformation. This appeared to envolve a study of the operating deformation systems in hafnium and the theoretical and experimental study of the textures resulting from plastic deformation. These were to be analyzed in comparison with the other hexagonal metals.

It became evident immediately that the research techniques which must be evolved …

Phase Relationships In The Quaternary System Lime-Titania-Zirconia-Silica, Robert Martin Gruver

Doctoral Dissertations

"The phase compatibility relationships for the quaternary system lime-titania-zirconia-silica have been determined by a solid-phase-reaction technique.

Preliminary division of the system into Alkemade tetrahedra was based on the phases found in samples by X-ray diffraction analysis. These samples covered the entire volume of the tetrahedron in a systematic fashion. When the quaternary system had been divided into regions or compatible phases, an analytical method was used to calculate the phase composition of each sample. The relative amounts of each phase in a sample determined by X-ray analysis were compared with the calculated quantities, and agreement between the two methods verified …

Preparation And Separation Of Metallic Chlorides, Norbert Felix Neumann

Doctoral Dissertations

"The use of chlorine and chlorine compounds as metallurgical reagents has long been known to the metallurgical industry. Recent developments in corrosion resistant metals and alloys as well as new equipment and techniques have led to a revival of chlorine processes. Many of the objections to the use of chlorine in metallurgical operations have been overcome and many are being reconsidered, as evidenced by the new processes in which chlorine and chlorides are the primary reagents. The Betterton process employs chlorine or lead chloride for the dezincing of lead. Ductile zirconium and titanium have been made by reducing their chlorides …

Nanbo₃ - Batio₃ - Basno₃ Ceramic Dielectrics, William Dean Mckee

Doctoral Dissertations

"A. The Problem.

The purpose of this investigation was to form by ceramic processes a number of compositions in the ternary system NaNbO₃ - BaSnO₃ - BaTiO₃, to determine certain dielectric properties of these, to study them by means or x-ray diffraction, and to determine the extent or correlation possible between the compositional variation of dielectric properties and the x-ray results.

Compositions investigated contained 50 mole percent or less BaSnO₃. Materials and methods of forming were chosen with the intent that the final bodies should be pure oxide compositions as represented in the ternary …

An Investigation Of The Characteristics Of High Alumina Refractory Castables, Gajendra Nath Mohanty

Doctoral Dissertations

"Refractory castables or concretes, a comparatively new member of the refractories family, are an admixture of highly aluminous cements and graded refractory aggregates, blended in predetermined proportions very much like structural concrete. The refractory aggregates must contain a large amount of fines contrary to the requirements of ordinary concrete. Unlike the Portland cements, which are mainly combinations of calcium silicates, the highly aluminous cements are predominantly calcium aluminates. They are comparatively of a refractory natures, having the hydraulic setting property combined also with high early strength. The discovery of the fact that these refractory concretes could be cast, in situ, …

A Study Of The Deformation Texture And Its Variation In Cold Drawn Nickel Rods, Krishan Kumar Tangri

Doctoral Dissertations

"The production of rods by cold drawing is a development of recent years as compared to other methods of fabrication. Though a good many investigations correlating the observed mechanical properties to the mill practices employed have been reported, the results nevertheless are more of a qualitative and empirical nature. It is well known that the physical properties of a metal product are related to its deformation textures which are characteristic of the metal and the fabricating method used. Thus a study of the deformation textures of cold-drawn rods, specially by x-ray diffraction techniques should provide a much more precise and …

Hydrogen Overvoltage On Titanium, Sheng-Tai Shih

Doctoral Dissertations

"The hydrogen overvoltage has been defined as the difference between the potential of the working electrode (cathode) and the theoretical reversible value for the same solution. This definition brings out the difficulty involved in the measurement of the "theoretical reversible potential for the same solution” as the potential of the hydrogen electrode in such a solution is usually different from the value of a standard reversible hydrogen electrode, for which the activity of hydrogen ions is set as being “1” and the potential arbitrarily set as being “0”. Besides, it is sometimes necessary to add addition agents to the solution …

A Study Of The Bonding By Air-Setting Refractory Mortar At Elevated Temperatures, Bhikhubhai Mahadeo Sedalia

Doctoral Dissertations

"The importance of a suitable material for the laying of bricks in furnace and kiln construction has been recognized by the refractory industry for a long time. It is necessary that a strong bond should develop between the bricks to impart strength to the entire construction work. A weak joint would form the weakest link and dangerously weaken the whole structure.

Such being the importance of the bond, the refractory industry has made quite an effort to develop jointing materials which would produce strong bonds. During the last two decades, due to intensive research and development work, many good bonding …

Carbon Monoxide Attack Of Refractories, William A. Frad

Doctoral Dissertations

"The disintegration and failure of fire clay refractories due to the action of carbon monoxide has been studied tor a period at about fifty years. The most important application is in blast furnace refractories. Similar failures due to carbon deposition, involving other gases such as methane, have been noted and less extensively studied. Failures due to the action of gases other than carbon monoxide are beyond the scope of this thesis. Occasional attempts to find some agent to prevent disintegration have been mentioned in the literature. In this study the number of such substances and the results of their action …

The Rate Of Dissolution Of Aluminum In Hydrofluoric Acid, Yen-Ngen Wang

Doctoral Dissertations

"Pure aluminum has a relatively low strength, and its use is, therefore, rather limited. However, the resistance of pure aluminum to the attack of acids and many neutral solutions is higher than that of less pure aluminum or most of the aluminum-base alloys. For this reason, alclad alloy sheets, are made with a coating of pure aluminum on one or both sides of an aluminum alloy core. The coating is metallurgically bonded to the core over the entire area of contact. Thus the coating electrochemically protects the core from corrosive attack.

Aluminum is more negative in the electrochemical series than …

A Study Of The Dissolution Of Titanium In Acids With Ammonium Fluoride Added, Charles Burroughs Gill

Doctoral Dissertations

"Titanium can no longer be considered a rare metal, even though the modern era of its production came into being only a few years ago. The first discovery of titanium was in 1791 by an English clergyman, the Reverend William Gregor, and the name titanium became universally adopted when so called by a German mineralogist, Martin Klaproth, who rediscovered titanium three years later. Not until 1887 was the relatively pure, 75 percent, metal prepared by L. F. Nilson and O. Pettersson, whose experiments were repeated in 1910 by M. A. Hunter. Hunter is given credit for producing the first metallic …

Shaped Charges: Their Mechanism And Applications In Mining, Pranlal Girdharlal Sheth

Doctoral Dissertations

"A shaped charge, confined or unconfined, is a unit of explosive material with a cavity or hollow at the base. It behaves differently than an ordinary charge, and, when detonated, has been found to produce curious effects of concentrating the force of the explosive on an area opposite the cavity"--Introduction, page 1.

Determination Of Progressive Corrosion Of Clay Flux Blocks, Ved Prakash Maheshwary

Doctoral Dissertations

"The Problem. Corrosion of refractories by molten corrosive liquids like molten slags and glasses is of general occurrence in those parts of the furnaces where they come in contact with the liquids. The life of a furnace generally depends upon the progressive rate of corrosion of the refractories by the slags and glasses. There have been various methods used by the investigators to ascertain the useful life of a refractory product before its use in the furnaces, but the problem is so complex that even after decades of research work by the research engineers and technologists a satisfactory and easy …

An Investigation Of The Deformation Textures Of Titanium, Dean Nesbit Williams

Doctoral Dissertations

"With the increase in production of titanium in recent years has come a great interest in the mechanical properties and in the possible uses of this metal. Due to the affinity of titanium for oxygen, nitrogen, carbon, and hydrogen, and the market effect of these elements on the mechanical properties, much of the work previously reported is unreliable. As purer commercial grades of titanium and high purity iodide titanium have become available for examination, research has been undertaken to correct and expand the knowledge of the properties of titanium. Although the uses of titanium are limited at the present time, …

The Underground Electrocarbonization And Gasification Of Mineral Fuels, Erich Sarapuu

Doctoral Dissertations

"The development of underground gasification methods for recovering mineral fuels is comparatively recent and several methods have been evolved for treating the various source materials. The problem of recovering solid and liquid fuels by underground gasification in gaseous form was primarily approached by means of opening underground entries which created the required fire-drift for starting the gasification in place.

Increasing knowledge of the whole problem of gasification in situ led to the evolution of new improvements in the underground gasification technique and, in the course of progressive research the preparations required for starting the gasification were accomplished from the surface. …