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Alkali Mobility And Mechanical Relaxation In Mixed-Alkali Silicate Glasses, James W. Fleming Jr.

Masters Theses

"Internal friction and sodium and potassium self-diffusion coefficients for (1-X)Na₂O · XK₂O· 3SiO₂ glasses were measured. Alkali diffusion was measured between 300 and 500ºC using radioactive isotopes and a thin-sectioning technique. Internal friction was measured from room temperature to 500ºC, 0.1 to 2000 Hz. Comparison between alkali diffusion and internal friction data for Na-K glasses with those for other mixed-alkali glasses shows that the mixed-alkali peak is related to alkali mobility. It is concluded that the mechanism for mixed-alkali internal friction is a cooperative rearrangement of dissimilar alkali ions, with the slower moving ion controlling the rate of reorientation"--Abstract, page …

A Study Of The Effects Of Mixing On The Accelerated Anaerobic Digestion Of Concentrated Municipal Sludges, Victor Darryl Orr

Masters Theses

"Most domestic sewage treatment plants today practice anaerobic digestion of sludge. The purpose of this investigation was to determine if thorough mechanical mixing of concentrated sludge would improve its digestion. The simulated digesters consisted of six 1 gallon anaerobic reactors which were operated in the laboratory for 78 days. The contents of three digesters were continually mixed and their responses were compared with those of the similarly loaded remaining three unmixed units. Raw sludge with solids concentrations of 7.5, 15 and 30 per cent was digested for detention periods of 30, 15 and 7.5 days at 33º C. Various analyses …

The Thermal Contact Resistance Of Lubricant Films In Vacuum, Garry A. Heizer

Masters Theses

"This paper presents the results of an experimental investigation on the thermal contact resistance of lubricant films and bare interfaces. The apparatus and procedure used in the determination of these resistances are described. Twelve series of tests were performed to evaluate the effects of temperature and contact pressure on the thermal resistance of lubricant films. Variations of thermal contact resistance with temperature and contact pressure for four lubricants and for bare interfaces are presented graphically. The thermal resistances of the four lubricants tested in vacuum conditions: lithium grease, graphite grease, molykote grease, and silicone lubricant, were found to lie in …

The Effect Of Solvents On The Desorption Of Phenol From Carbon In A Water Free System, William W. Knickmeyer

Masters Theses

"The desorption of phenol from active carbon was studied using a continuous flow desorber. The system used was nearly water free to reduce water-phenol interactions. The ten solvents used in this study exhibited a wide difference in their desorption capabilities. An attempt to correlate the desorption data with the physical properties of phenol and solvents, in addition to regular solution theory, proved unsuccessful. A thermodynamic approach using the linear free energy-enthalpy relationship produced a general trend by using the heat of solution for phenol in solution and a reasonable correlation using the heat of formation of the phenol-solvent hydrogen bond …

Anodic Oxidation Of Ethylenediaminetetraacetic Acid On Pt In Acid Sulfate Solutions, Howard Ho-Wei Jiang

Masters Theses

"The anodic oxidation of EDTA was studied in acid sulfate solutions on platinized-Pt at 25ºC. Polarization relationships were obtained for the EDTA concentration range 3. 42 x 10⁻⁵ to 3. 42 x 10⁻³ M and pH range 0. 35 to 3. 80. Numerous reaction products were identified that indicated a sequential removal of acetate groups from the EDTA, each by an initial decarboxylation followed by a reverse Schiff-type reaction, that produced formaldehyde and the corresponding amine. A reaction sequence which correlated the experimental data involved Frumkin-type adsorption of the EDTA species through an unionized acetate group followed by a rate-determining …

An Energy Solution For Vibration Characteristics Of Free Thin Cylinders, Dale Elmer Leanhardt

Masters Theses

"In this report the flexural vibrations of the walls of free, thin, circular cylinders are considered. Theoretical expressions are developed for the natural frequencies by extending the approximate energy method of Arnold and Warburton to the free-free case. Furthermore, the developed expressions are shown to apply, as special cases, to the fixed-fixed and simply-supported cylinders analyzed by Arnold and Warburton. The energy solution for free-free cylinders is checked both experimentally using a 3500 pound-force, 5 to 2000 hertz, vibration exciter and numerically using the well documented SABOR IV-DYNAL finite element program. While the derived energy method accounts for any prescribed …

A Study Of Radiative Heat Transfer From A Spherical Layer, Hakimuddin Kalimuddin Khalil

Masters Theses

"The problem of radiative heat transfer from a spherical layer of absorbing-emitting gas has been studied. First, the medium is assumed to be gray and then nongray. A thorough survey of literature from fields other than heat transfer, such as astrophysics and neutron transport has been made to stimulate further interest in this important area. To gain some insight into the effect of various parameters on the heat transfer, simple physical situations involving isothermal medium are considered. Comparison of the results obtained for the flux from the spherical and planar layers reveal that the curvature becomes increasingly important as the …

Hydrostatic Extrusion Of Tubular Products, John Lester Roth

Masters Theses

"The production of quality tubular products by hydrostatic extrusion has been demonstrated to be a highly satisfactory method. The forming of tubes by the floating mandrel method has been accomplished on mild steel, aluminum alloy, and brass. This thesis describes the method, equipment design and operation, and the results obtained in the hydrostatic tube extrusion. A discussion on the advantages of the use of hydrostatic over conventional extrusion is included. The hydrostatic extrusion system designed for this study is described in detail"--Abstract, page ii.

A Study Of The Void-Strengthening Of Aluminum And Its Nature, Purushottam G. Manusmare

Masters Theses

"Strengthening of aluminum by formation of the voids and the nature of resultant strengthening, viz., the temperature and the strain rate dependence of its yield strength were studied. Aluminum wires with 99.999% purity and of 3.1 mm diameter were quenched and heat treated to form voids of the approximate density 10¹³-10¹⁴ voids/cm³ and were tested for their yield strength. Voids in selected samples were observed by transmission electron microscopy using the Hitachi HU-11A microscope. The yield strength of the void strengthened samples was measured at various temperatures from 77ºK to 593ºK using two strain rates, 3.33 x 10⁻²/sec and 1.67 …

Two Component Heat Pipe, Surapol Chandsawangbhuvana

Masters Theses

"A two component heat pipe with water and ethanol as the working fluid was investigated at different angles of inclination and various ethanol concentration for two power loads. The heat pipe was 15 inches long and 0.75 inches in diameter with a 100 mesh stainless steel screen wick. The wall and the vapor temperatures were measured at different stations along the length of the heat pipe by copper-constantan thermocouples. The results were used to evaluate an existing model which includes the constraint of thermodynamic phase equilibrium of the solution on the governing equations. Based on the measured pressure and temperature …

Factors Affecting The Ductility And Microstructure Of Ti-6al-6v-2sn Titanium Alloy Weldments, Michael John Ball

Masters Theses

"The purpose of the investigation was to study the effect of material thickness, weld heat input and post weld heat treatment on the tensile properties and microstructure of Ti-6Al-6V-2Sn Titanium, and obtain a practical weld/thermal treatment cycle. The objectives were accomplished by electron beam and gas tungsten arc welding 0.060, 0.125 and 0.250 inch thick material and then heat treating at various temperatures and times. Electron beam and gas tungsten arc welding enabled an approximate 4:1 ratio of heat inputs to be utilized. Resultant welded and heat treated material was tensile tested and metallographically examined. Heat treatments involved both air …

Radiant Interchange In A Non-Isothermal Rectangular Cavity, Tilak Raj Sawheny

Masters Theses

"Radiant interchange between non-isothermal, gray diffuse surfaces with non-uniform radiosity has been determined for a rectangular cavity. Temperature distribution and heat flux as thermal specifications for the parallel surfaces of the cavity have been considered separately. Ambarzumian's method has been used for the first time to solve a radiant interchange problem. According to the method, the integral equation for the radiosity is first transformed into an integro-differential equation and then into a system of ordinary differential equations. Initial conditions required to solve the differential equations are the H-functions. The H-functions represent the radiosity at the edge of the cavity for …

The Use Of Scattering Parameters In Amplifier Design, Yousef Neman-Ebrahim

Masters Theses

"The scattering-parameter formulation of an active two-port device is developed from the compensation theorem. The use of scattering parameters in graphical developments of forward operating power gain and tunability is considered in detail. Finally, two design examples show the application of the graphical procedures"--Abstract, page ii.

Digested Sludge Dewatering On Drying Beds Under Controlled Environmental Conditions, Daniel James Harris

Masters Theses

"The dewatering characteristics of anaerobically digested primary and activated sludge were investigated under eight selected combinations of laboratory controlled air temperature and relative humidity using three open, drained model beds, as well as a closed, drained and an open, nondrained bed. The evaporation rate from a free water surface was also determined. Moisture content, drainage, evaporative weight loss, and sludge surface recession were measured and recorded periodically throughout the two week period of each of the eight experiments. Relationships were shown to exist between sludge moisture content, evaporation rate from a free water surface, and the parameters 6T (the difference …

The Anodic Dissolution Of Tungsten, James W. Johnson, Cheng-Hsiao Wu

Chemical and Biochemical Engineering Faculty Research & Creative Works

The anodic dissolution of tungsten was studied in H₂SO₄-K₂SO₄ solutions (pH = -2 to 2.5) and K₂SO₄-K₂CO₃-KOH solutions (pH = 11.5 to 14.5) at 25 C. Faradaic efficiency studies in basic solutions showed the metal to be oxidized to the +6 state. In acid solutions, a thick protective film of yellow WO₃ was formed. Polarization curves possessed linear Tafel regions (slope ~ 2.3 RT/F) at potentials slightly more positive than the rest potentials. An anodic dissolution mechanism is proposed which involves a surface film …

X-Ray And Neutron Diffraction Study Of The Holmium-Iron System, Michael Fred Simmons

Doctoral Dissertations

"Neutron diffraction and x-ray powder studies have been made of holmium-iron intermetallic compounds. The magnetic moments of Ho and Fe are in good agreement with measured spontaneous magnetization assuming a ferrimagnetic model with the Ho moments antiparallel to the Fe moments. The magnetic moments of the Fe atoms are found to be localized and thus independent of the rare earth content in the alloys. In contrast to HoCo₃, (00ℓ) type magnetic peaks in the neutron diffraction patterns are still prevalent at room temperature and gradually decrease as the Curie temperature is approached. This fact indicates that the easy direction of …

A Magnetic Aftereffect In Dilute H.C.P. Co-C Alloys, J. R. Keiser, Manfred Wuttig

Materials Science and Engineering Faculty Research & Creative Works

A magnetic Dis accommodation in dilute h.c.p. Co-C alloys has been observed around 90°C. The thermally activated process giving rise to the Dis accommodation is characterized by an activation energy of 26 kcal mole-1 and an attack frequency on the order of 10+13 sec-1. An application of the selection rules shows that the Dis accommodation cannot be caused by the redistribution of tetrahedral or octahedral interstitials or any nearest neighbor interstitial pairs as long as the defects interact linearly with the internal magnetic field. © 1971.

On The Activation Entropy Of Interstitial Diffusion In B.C.C. Iron, Manfred Wuttig

Materials Science and Engineering Faculty Research & Creative Works

No abstract provided.

Parameter For Comparing Anemometer Response, L. M. Fingerson

Symposia on Turbulence in Liquids

In comparing the theoretical performance of sensors, the term e_b/q (voltage change due to change In heat transfer) was found to be a fundamental sensor parameter. This was true for both sensitivity and frequency response in both constant current and constant temperature systems. Equations and data are presented for calculating this parameter for most wire and film sensors. Wedges, cones, and other non-cylindrical sensors have not been included because of their special problems at low frequencies due to conduction losses.

Internal cooling of the sensor is used for high temperature environments. Calculations show that the sensitivity at low …

An Attempt To Characterize The ‘Turbulence Burst Phenomena’ Using Digital Time Series Analysis, B. Johnson, R. Saylor

Symposia on Turbulence in Liquids

Several attempts to measure "periodicity" in the output signal of hot wires and hot films located in the viscous sublayer have been made in recent years. The usual method is to perform an autocorrelation on the signal and to interpret the strong peaks in the correlation function as indicative of the mean period of the "turbulence bursts" during a particular sampling interval.

The data analyzed for the presence of "turbulent bursts" were from the test of a 60-foot, 8-oared racing shell at the David Taylor Model Basin of the Naval Ship Research and Development Center. The shell was instrumented with …

Conference Proceedings Of The Symposium On Turbulence In Liquids October 4-6, 1971, University Of Missouri--Rolla

Symposia on Turbulence in Liquids

No abstract provided.

Mixed‐Cation Effect In Silver Borate Glasses, E. N. Boulos, N. J. Kreidl

Materials Science and Engineering Faculty Research & Creative Works

No abstract provided.

The Anodic Dissolution Reaction Of Insb: Etch Patterns, Electron Number, Anodic Disintegration, And Film Formation, Martin E. Straumanis, Lih Da Hu

Materials Science and Engineering Faculty Research & Creative Works

The etching behavior of the inverse {111} planes of undoped, semiconducting, n-type, InSb single crystals was explored. Depending upon the etchant, including anodic dissolution, various etch patterns were obtained on the inverse planes. In general, the etch pits on the In{111} plane were round, and the face was shiny, whereas the face of the inverse plane was dark and rough. The rates of dissolution in the electrolytes used were very low, especially in absence of oxidizers. The components dissolve as In3+ and Sb3 +. At current densities above 40 or 60 mA cm-2 (on Sb{111} or In{111}), growth of a …

Stored Energy Of Room Temperature Deformed Copper, G. J. Filatovs, Hollis P. Leighly

Materials Science and Engineering Faculty Research & Creative Works

No abstract provided.

Thermal Expansion Of Pb3o4, Charles A. Sorrell

Materials Science and Engineering Faculty Research & Creative Works

Thermal expansion of Pb₃O₄ was investigated by high‐temperature X‐ray diffraction. The coefficient in the a0 direction is 14.6x10−6/°C. Expansion in the c0 direction is 32% greater, with a coefficient of 19.3x10−6/°C. Coefficients of expansion are linear from 25° to 490°C and are comparable with those of tetragonal and orthorhombic PbO. Copyright © 1971, Wiley Blackwell. All rights reserved

Structure And Properties Of Silver Borate Glasses, E. N. Boulos, N. J. Kreidl

Materials Science and Engineering Faculty Research & Creative Works

Clear glasses form in the system Ag₂O‐B₂O₃ up to about 35 mol% (65 wt%) Ag2O. Infrared absorption, thermal expansion, and density data indicated an analogy to the Na₂O‐B₂O₃ system. Pentaborate‐triborate group pairs appear to be formed on addition of Ag₂O to B₂O3 up to 20 mol% Ag2O and diborate groups from 20 to 33 mol% Ag₂O. This interpretation is supported by the comparison of the infrared absorption spectra of quenched and crystallized glasses. One crystallization product, Ag₂O‐4B₂O₃, was …

Activation Volumes Of Interstitial Diffusion In Ferromagnetic Metals And Alloys, Manfred Wuttig, J. Keiser

Materials Science and Engineering Faculty Research & Creative Works

The Dis accommodation technique was used to determine the activation volumes of carbon diffusion ΔV of a Fe-1.4 wt% Si alloy, of hcp cobalt, and of nickel at the temperatures of -21, 75, and 110°C, respectively. The obtained values of ΔV are +0.3 ± 0.3 and -0.6 ± 0.9 cm3 mole-1 for the two relaxations observed in hcp cobalt, and 1.2 ± 0.1 cm3 mole-1 for nickel. These results are discussed in terms of a continuum model that interprets the activation energy of diffusion as a sum of the strain and exchange energies. It is found that in ferromagnetic solids …

Density Distribution Measurements In Rarefied Gases Contained Between Parallel Plates At High Temperature Differences, Darryl J. Alofs, Richard C. Flagan, George S. Springer

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Density Distributions Were Experimentally Determined in Rarefied Gases at Rest Contained between Two Parallel Plates Maintained at Widely Different Temperatures. the Temperatures of the Hot and Cold Plates Were ∼79°K and ∼294°K, Respectively, Resulting in a Temperature Ratio of About 4:1. Both Helium and Nitrogen Were Used as Test Gases. Particular Attention Was Focused on Obtaining Data in the Temperature Jump and Transition Regimes. the Gas Densities Were Measured by Observing the Luminescence Produced by a High-Energy Electron Beam Traversed between the Plates. in Addition to the Density Measurements, Heat Transfer Measurements Were Also Made in Order to Estimate the …

Cylindrical Couette Flow Experiments In The Transition Regime, Darryl J. Alofs, George S. Springer

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Density Distributions Were Measured in Rarefied Argon Contained between Two Concentric Cylinders, the Inner One Rotating, the Outer One Stationary. the Experiments Were Performed with a Mach Number Near Unity, based on the Surface Speed and Surface Temperature of the Rotating Cylinder. Particular Attention Was Focused on Obtaining Data in the Slip and Transition Regimes Where the Knudsen Number, Defined as the Ratio of the Mean Free Path to the Gap Size between the Cylinders, Varied from 0.04 to 1.07. the Density Distributions Were Measured by Observing the Gas Luminescence Induced by the Passage of a Narrow Beam of High …

The Axial Contact Of Finite Elastic Cylinders With Application To Thermal Contact Resistance, Ross Orlo Mcnary

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Predictions of the macroscopic thermal contact resistance have been severely restricted because the macroscopic contact area between finite members could not be determined. A new method of solution to this contact problem in elasticity is developed which is applicable to a wide variety of geometries and boundary conditions. A physical lumped-parameter model is employed from which the finite difference equations in terms of displacement are derived. Calculations using this method indicate that large errors in the prediction of the thermal contact resistance can result if solutions for bodies of infinite extent are employed for finite regions of interest. Especially large …