Engineering Commons^™

An Investigation Of The Radiation Polymerization Of Methyl Methacrylate-Kaolin Clay Composites, James Jackson Beeson

Doctoral Dissertations

"A kinetic and characterization study has been made on the effects of gamma-rays (Co⁶⁰) on the polymerization of a 50-50 weight mixture methyl methacrylate (MMA) kaolin clay system. The effect of dose rate (7.35 - 24.9 rads per second), temperature (25 to 75ºC) and total dose on the percentage conversion of monomer to polymer was studied. The rate of formation of polymer at 25ºC in the composite system was found to be faster when compared to a bulk MMA system at the same experimental conditions. This acceleration showed that the clay had a catalytic effect on the formation of polymer. …

Activation Volumes Of Carbon Diffusion In F.C.C. Iron-Nickel Alloys, James Raymond Keiser

Doctoral Dissertations

"The disaccommodation technique was used to determine the activation volume of carbon diffusion, ΔV, in six fcc iron-nickel alloys. Measurements were made at temperatures ranging from 68ºC to 90ºC and pressures up to six kilobars on samples having a nickel content between 31 and 63 at. %. A maximum activation volume of 3.9 cm³/mole was found at 34 at. % nickel. The compositional dependence of ΔV is satisfactorily reproduced by a magnetic energy continuum model in which it is assumed that the activation free energy of diffusion is essentially ferromagnetic in origin "--Abstract, page iii.

An Investigation Of Subsequent Yield Phenomena, Joseph George Hoeg

Doctoral Dissertations

"A method utilizing high pressure fluid environments is described whereby a three-dimensional subsequent yield surface was determined for 304 stainless steel. Cylindrical parent specimens of this material were prestrained in axial compression under fluid pressure and then small sub-specimens were sectioned from these parent specimens. Finite element techniques were used to optimize the parent specimen size so that a zone of uniform axial stress would result during the prestraining. Longitudinal strains in this zone were monitored during the prestraining and the sub-specimens were cut from this region in a manner that did not allow the machining to appreciably affect the …

An Age Hardening Study Of Magnesium-Thorium-Manganese Alloys, Kuldip Singh Chopra

Doctoral Dissertations

"The age hardening processes in Mg-3.5 wt.% Th-1.0 wt.% Mn and Mg-1.0 wt.% Th-1.0 wt.% Mn alloys have been studied by light and electron microscopy, and by electron and X-ray diffraction. At aging temperatures of 300ºC and below, G.P. zone formation rapidly hardens these alloys followed by the precipitation of disc shaped plates during averaging. During aging above 300ºC, no G.P. zones form and the disc shaped precipitate grows to very large sizes. The combined results of X-ray and electron diffraction indicate that the disc shaped precipitate has a Mg₃Cd (DO₁₉) type structure. The basal plane of the Mg₃Th discs …

Use Of The Turbulence Kinetic Energy Equation In Analyzing Turbulent Near Wakes, James Edward Auiler

Doctoral Dissertations

"A general method is presented for analyzing turbulent flow fields in the near wake regions of two-dimensional and axisymmetric bodies. The governing partial differential equations of continuity, momentum and turbulence kinetic energy are expressed in elliptic form in terms of the dependent variables stream function, vorticity and turbulence kinetic energy. An iterative finite-difference technique is used to solve the governing equations simultaneously. Numerical solutions are obtained for the following physical problems: 1. Laminar near wake: Only stream function and vorticity are considered for laminar flow. Solutions are compared with available analytical results for uniform flow over a sphere. 2. Turbulent …

Internal Friction Of Ion Exchanged Li₂O•Al₂O₃•2sio₂ Glasses, A. Ismail A. Abdel-Latif

Doctoral Dissertations

"Li₂O•Al₂O₂•2SiO₂ glass fibers were ion-exchanged from 1 to 300 minutes in a sodium nitrate bath at 366ºC. The internal friction was measured along with the lithium and sodium concentration profiles. As sodium progressively replaced lithium, the alkali internal friction peak became smaller while a new peak (mixed alkali peak) appeared and increased in magnitude. These changes in the internal friction are similar to those that occur upon the addition of a second alkali to glasses prepared by conventional melting. The magnitude of both internal friction peaks in ion exchanged glasses was dependent on the overall glass composition. The magnitude of …

Dynamic Behavior Of Eccentrically Stiffened Plates, Charles Stuart Ferrell

Doctoral Dissertations

"The dynamic behavior of eccentrically stiffened rectangular plates is studied by the finite element method. The addition of stiffeners to a plate structure is a common method of increasing the rigidity of the structure with a minimum of weight increase. However, this stiffened plate configuration does not easily lend itself to analysis. This study is an approach to finding a rational method by which the dynamic behavior of such a stiffened plate structure may be determined. The governing differential equations for the finite element model are derived and the stiffness and mass matrices for the plate and stiffener elements are …

Statistical Study Of Rock Drilling By Hypervelocity Jets From Explosive Shaped Charges, John William Brown

Doctoral Dissertations

"The drilling effect in rock of hypervelocity jets from explosive shaped charges was investigated experimentally to supplement a rapid excavation concept. The effects of the design factors of the charge and the mechanical properties of eight rock types were studied. Experiments were both designed and analyzed upon statistical principles. A full factorial experimental design was used for each of seven rock types. An analysis of variance and the k-ratio least significant-difference test were applied to the results.

The optimum design of shaped charges for drilling was found to be independent of rock type and rock properties. For composition C-4 charges …

Identification Of Linear Systems With Delay Via A Learning Model, Hugh Francis Spence

Doctoral Dissertations

"The effects of input delay on an identification scheme using a learning model are investigated. The parameter adjustment laws for the learning model are derived through Lyapunov methods similar to those used for the model reference adaptive control systems of Parks. For no measurement noise or delay mismatch between the learning model and system, the parameters are adjusted to bring the error between model and plant to zero. When there is delay mismatch between the inputs of the learning model and the unknown system, the convergence of the parameters of the learning model to those of the unknown system is …

Surface Reactions Of Boron With Clean Tungsten Substrates, Thomas A. Flaim

Doctoral Dissertations

"A model developed to predict adsorbate-induced work-function changes for thermionic emitters is shown here to apply to a more general class of electron emission phenomena and a much broader range of adsorbates. This model predicts that chemically, vapor-deposited boron will increase the work function of a clean tungsten substrate at coverages between 0 and 1 monolayer. This is the first time that a single model has been shown to predict both positive and negative work function changes for different adsorbates. The reactions of chemically, vapor-deposited (CVD) boron with clean tungsten substrates were studied using field emission microscopy (FEM) and low …

The Effect Of A Knurled Heat Transfer Surface Upon Pool Nucleate Boiling Of Normal Pentane, Jerry James Carr

Doctoral Dissertations

"The effect of knurling a nucleate boiling heat transfer surface was studied. The knurling utilized produced regular, four-sided, adjacent pyramids with an apex angle of 90 degrees. Four knurling densities were used ranging from 416 to 2591 pyramids per square inch. The transfer surface was gold-plated copper and the heaters used were electrically heated, ten-inch long, horizontal cylinders of one-inch diameter. The liquid boiled was normal pentane at its saturation temperature and a pressure of 760 millimeters mercury.

For some of the knurled surfaces the temperature difference required to produce a given heat flux was found to be less than …

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 …

Diffusion In Wide Grain Boundaries, J. Mimkes, Manfred Wuttig

Materials Science and Engineering Faculty Research & Creative Works

The rigorous solution of the grain-boundary diffusion problem has been approximated by a series expansion method. The calculations show that higher-order terms may be neglected in the bulk adjacent to the grain boundary. Thus, in this region Whipple's and Suzuoka's solutions represent a close approximation to the problem. Inside the grain boundary, however, higher-order approximations have to be taken into account. These approximations gain importance in the case of wide grain boundaries. The solutions obtained for an instantaneous source have been fitted to available grain-boundary diffusion data of Ni2+ in MgO at 1200°C. Numerical calculations give for the bulk diffusion …

Thermal Expansion Of Tungsten At Low Temperatures, Jayant S. Shah, Martin E. Straumanis

Materials Science and Engineering Faculty Research & Creative Works

No abstract provided.

Rotating Cylinder Apparatus For Rarefied Gas Flow Studies, Darryl J. Alofs, George S. Springer

Mechanical and Aerospace Engineering Faculty Research & Creative Works

A Rotating Cylinder Type Apparatus is Described, Suitable for Determining Drag in Cylindrical Couette Flow of Rarefied Gases, and for Evaluating Tangential Momentum Accommodation Coefficients at Gas-Solid Boundaries. the Apparatus is Equipped with a Damping Device using Diffusion Pump Oil for Eliminating Undesirable Oscillations in the System. Tangential Momentum Accommodation Coefficients of Argon on Aluminum Were Determined with an Accuracy of ±2.5%. the Results Obtained Indicate that the Apparatus May Be Used over a Wide Pressure Range, Corresponding to Free Molecule and Continuum Flow Conditions. © 1970 the American Institute of Physics.

Phase Equilibria And Thermodynamic Studies In The System Cao-Feo-Fe2o3-Sio2, M. Timucin, Arthur E. Morris

Materials Science and Engineering Faculty Research & Creative Works

Phase equilibria and thermodynamic properties of the system CaO-FeO-Fe₂O₃-SiO₂ were studied at 1450° and 1550°C, over a range of pO₂ from 1 to about 10-11 atm. Isothermal phase diagrams and activity-composition diagrams were constructed for 0, 5, 10, 20, and 30 wt pct SiO₂ sections. The data are applicable to further understanding the behavior of simple BOF steelmaking slags. © 1970 The Minerals, Metals & Materials Society - ASM International - The Materials Information Society.

A Role For Educational Institutions In Housing Development, Paul J. Grogan

International Symposia on Low Cost Housing Problems

No abstract provided.

Low Cost Housing (How To Avoid The “Problem” In Three Words Or Less), Carl P. D. Sharpe

International Symposia on Low Cost Housing Problems

No abstract provided.

Modular Housing, Herbert Behrend

International Symposia on Low Cost Housing Problems

No abstract provided.

Development By Means Of Semi-Permanent Building: A New, Practical Approach In Housing And City-Planning, B. E. Friedjung

International Symposia on Low Cost Housing Problems

No abstract provided.

"The Buckle-Shell", V. J. Meyers, V. C. Matzen

International Symposia on Low Cost Housing Problems

No abstract provided.

Low Cost Housing In The Perspective Of Metropolitan Calcutta’S Urban Renewal, S. Ghosh Dastidar

International Symposia on Low Cost Housing Problems

No abstract provided.

A Building System Using Precast Concrete Sandwich Panels From Footing To Roof, E. L. Hansen, J. O. Curtis

International Symposia on Low Cost Housing Problems

No abstract provided.

A Hyper-Roof Concept For Low-Cost Housing, John V. Huddleston

International Symposia on Low Cost Housing Problems

No abstract provided.

An Experiment In Low Cost Housing In Stillwater, Oklahoma, William H. J. Cleverly, Phillip G. Manke

International Symposia on Low Cost Housing Problems

No abstract provided.

The Mobile Home Is Low-Cost Housing -- Or Is It?, Walter L. Meyer

International Symposia on Low Cost Housing Problems

No abstract provided.

Cultural Bases Of Preference For The Visual Appearance Of Residential Environments, Peter G. Flachsbart, George L. Peterson

International Symposia on Low Cost Housing Problems

No abstract provided.

A Self-Help Process For Low Cost Housing Construction In Pittsburgh, Dennis H. Parr

International Symposia on Low Cost Housing Problems

No abstract provided.

Low Cost Housing Projects In India, A. R. Santhakumar

International Symposia on Low Cost Housing Problems

No abstract provided.

Low Income System Key Assembly, Darin V. Liska

International Symposia on Low Cost Housing Problems

No abstract provided.