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The Effect Of 15% Mno On The Phase Relations In The System Cao-Feo-Sio₂ At 1450ºc, Aquil Ahmad

Masters Theses

"A study was made of the phase relations at 1450ºC in the systems CaO-FeO-SiO₂ and CaO-FeO-SiO₂ -15% MnO, in equilibrium with metallic iron. The stability region of different phases was determined by microscopic examination and electron-beam microprobe analysis of the quenched specimens. The effect of 15% MnO on the liquid saturation boundary of the system CaO-(FeO+MnO)-SiO₂ was discussed in terms of the effect of MnO on slag making reactions in the Basic Oxygen Furnace steelmaking process"--Abstract, page ii.

Quenching Defects In Aluminum Plus Ten Atomic Per Cent Zinc, James Thomas Grider

Masters Theses

"This study was undertaken to resolve the conflict which has recently arisen as to the as-quenched microstructure in the Al-Zn system as revealed by thin film transmission electron microscopy. The composition range of most active study has been that from 5 to 15 atomic per cent Zn in superpurity AL. Consequently a composition of 10 atomic per cent Zn was chosen for this study. There are no discontinuties in the phase diagram in this composition range which would influence the above choice. It exists as a single phase solid solution at high temperatures and as a two phase alloy at …

The Design Of A High Temperature Thermoelectric Generator Element Using Silicon Carbide, John Talmage Barrow Jr.

Masters Theses

"This report presents the design of an optimum, high temperature silicon carbide thermoelectric generator element. The analytical efforts have been divided into three basic parts, the development of the theory, the accumulation of the data, and the optimization of the design. The first step in the theory development was the derivation of accurate design equations. With this done, the design philosophy and computer program were constructed, the latter utilizing a subroutine to contain the design equations. The data was obtained from a survey of many references and, for the most part, was found to be inexact, requiring the consideration of …

Low-Energy Electron Transport By The Method Of Discrete Ordinates, David E. Bartine

Doctoral Dissertations

"The one-dimensional discrete ordinates code ANISN has been adapted to simulate the transport of low-energy (on the order of a few MeV) electrons. Two different calculational techniques have been utilized for the treatment of electron-electron collisions that result in a small energy transfer. One method treats such collisions by a continuous slowing-down approximation, while the other method treats these collisions by the use of a very approximate cross section. Calculated results obtained with ANISN are compared with experimental data for the transmitted energy and angular distributions for 1-, 2.5-, 4-, and 8- MeV electrons normally incident on aluminum slabs of …

Interactions Between Selected Pigment Producing Bacteria Isolated From Sewage, Leslie Alexander Lakie

Masters Theses

"Pigmented bacteria have been of interest to the microbiologist for several years. The pigmented organisms in sewage have been known to gain predominance, but no investigations have been made to determine whether the pigment assists the organism in gaining predominance. During this study a number of bacteria which produced a water soluble pigment were isolated from sewage. These bacteria were grown in shaken flasks using tryptone Glucose extract broth as a medium. Growth studies of the bacteria in pure and mixed culture were performed to determine if the pigment could affect another bacteria's growth. Studies were also performed using the …

Reservoir Design: Simulation Techniques, Larry W. Mays

Masters Theses

"A simulation model is developed to aid in the analysis of small dams to reduce the possibility of inadequate spillway designs. Basic assumptions concerning the geometric aspects of the natural reservoir are made to develop the model which is based upon describing the timing and magnitude of a design flood passing through a reservoir. Simulation equations are derived from the basic continuity equation and describe reservoir outflow and storage as functions of reservoir depth. Newton's Iteration Technique is utilized to solve the simulation equations for the reservoir depth. The resulting simulation model determines an optimum size auxiliary spillway having a …

Electrolytic Reduction Of Zinc From Acidic Sulfate Solutions, Kenneth Dale Gielow

Masters Theses

"Cathode polarization curves were obtained for the electrodeposition of zinc from sulfate solutions with pH 2 and zinc concentrations of 10.0, 40.0, 80.0, and 100.0 gpl zinc. Both pure zinc and pure aluminum were used as cathodes with some difference in results noted. The effect of animal glue additions of 0.01, 0.10, and 0.50 gpl of solution on the cathodic polarization curves and the resulting deposit morphologies were determined. These glue additions correspond to 0.20, 2.0, and 10.0 pounds of glue per ton of zinc deposited, respectively. The slope of the Tafel region of the polarization curves was found to …

A Statistical Hydrologic Simulation Model, Ronald L. Wycoff

Masters Theses

"Simulation of a physical system requires knowledge of all components of the system and their interactions. A probabilistic simulation model of a hydrologic system is developed from short term continuous, sychronized rainfall-runoff records. The individual components of the system area the time between and duration of storms, the depth of rain occurring in each time period of the storm, precipitation excess relations, and the watersheds unit hydrograph. The available data is used to define or develop the probabilistic models involved. The only nonprobabilistic model employed is the watersheds unit hydrograph. It is found that the time between and duration of …

Calculation Of Eddy Current Loss Of A Disc, Kou Quen Chang

Masters Theses

"A method is presented to calculate the eddy current losses of a uniform disc with an opening in the center and excited by a circular current loopage First, the disc is subdivided into smaller concentric rings, then the self-inductances, the mutual inductances between these smaller rings, the mutual inductances between the excitation coil and the smaller rings, and the resistance of the rings are calculated. Next, the eddy current flowing in each ring is obtained by solving a complex matrix equation of the form [X] [I] = [V] where X is the impedance matrix, I is the eddy current matrix, …

Evaporation And Condensation Of Zinc, Shailesh Bhanuprasad Vora

Masters Theses

"Evaporation rates of liquid zinc were determined experimentally within the temperature range of 450º C to 575º C and at argon pressures ranging from 730mm Hg to 130mm Hg. Extrapolated values of these rates are found to be consistent with the previously reported rates obtained by St. Clair and Spendlove at lower pressures. Between 100 microns and one atmosphere pressure rates of evaporation seem to vary according to an equation of the form W = APᴮ, where Pis pressure and, A and B are constants. Similar experiments were performed with brass powders in atmospheres of argon and helium at temperatures …

Low Frequency Lumped Element Directional Couplers, Constantine Rodolph Jenkins

Masters Theses

"Lumped element directional couplers are desirable at frequencies below the VHF range because they eliminate the large physical size necessary for the distributed element directional couplers. The purpose of this work is to describe the theory and design of such low frequency lumped element directional couplers. A model for the coupler is developed and the equations which describe it are derived. Scattering matrices for one and two section couplers are obtained. Computer solutions for three section couplers are presented. Experimental results for one, two, and three section couplers are presented and comparison with theory are made. Comparisons of theoretical and …

Variable-Threshold-Mixed-Weight Threshold Element, Cheng-Chung Liu

Masters Theses

"A threshold element (TE) is a mathematical model of a class of logic gates. The desirability of a threshold element in the application of digital systems stems from its richness of logic power and its relative economy. On the other hand, the tighter tolerences required by the threshold logic element as compared to conventional logic gates have prevented them from being utilized extensively. The purpose of this thesis is to propose a versatile threshold element having high noise immunity and loose tolerance requirement. The proposed TE which has variable threshold and mixed weight capability uses current switching to enhance noise …

Practical Application Of Digital Computer To Distribution Systems, Juan Vincente Saavedra

Masters Theses

"Given a three phase ac power distribution system, a digital computer program is presented which determines a complete steady state solution for a given condition. The network data is processed by the computer into an admittance matrix, and these parameters are stored in a manner that enables the computer program to operate upon them as the coefficient of a simultaneous set of nonlinear equations. This set of equations are solved by the Gauss-Seidel Iterative Process improved by a modification of the relaxation method. Practical experience with the distribution system of the Davenport, Iowa, plant of the Aluminum Company of America …

Shear Properties Of An Organic Soil And The Same Soil With The Organic Matter Removed, David Eugene Daniels

Masters Theses

"The effect of strain rate on the shearing properties of an organic A̲ horizon Bryce clay and the same soil treated with hydrogen peroxide to remove the organic matter was studied. For both soils, the pore pressures were found to be independent of strain rate, and dependent only on the increment of strain during shear. The effect of the hydrogen peroxide treatment on the shear properties of an inorganic Bryce B̲ horizon clay was also studied. It was concluded that the hydrogen peroxide does not affect the mineral properties of the Bryce clay and serves only to selectively remove organic …

Phase Equilibrium And Thermodynamic Study Of The Iron-Copper-Carbon System, Krishna Parameswaran

Masters Theses

"Gas carburization experiments were conducted at 950ºC in order to study the phase relations and to determine the activity of carbon in the iron-rich corner of the iron-copper-carbon system. The solubility of graphite in equilibrium with iron-copper alloys was determined at 950º, 1000º, and 1050ºC. The results of gas carburization and graphite solubility experiments at 950ºC were used in constructing an isothermal section of the iron-rich end of the iron-copper-carbon phase diagram, on which are superimposed carbon isoactivity lines. Graphite solubility data at 1000º and 1050ºC were used to construct similar diagrams without the isoactivity lines. The effect of carbon …

A Hybrid Computer Solution Of The Swing Equation, Donald Wayne Shaw

Masters Theses

"Models for the governor and exciter control systems are presented and the development of a hybrid computing system including these models is described. A technique for including the governor and exciter effects into the solution of the power system swing equation is also discussed. A hybrid computing system consisting of an SCC 650 digital computer, hybrid interface, and an EAI-TR-48 analog computer is used to study five test cases. The test cases involve basically the same example system with different values for fault clearing times and machine inertias. The results of each test case are briefly discussed with relevance to …

Advanced Waste Treatment Of Industrial Waste Waters By Physicochemical Processes, Michael Gay Hardie

Masters Theses

"The primary objective of this investigation was to determine the general applicability of using physicochemical processes for treating different types of industrial wastes. Emphasis was placed on the evaluation of the treatment efficiency and the performance difficulties encountered in the treatment of each waste. Two types of waste were studied, one a high strength acidic industrial chemical waste and the other a petroleum refinery waste. The physicochemical system utilized included chemical coagulation and clarification plus activated carbon adsorption. Parallel operations of fixed-bed and expanded-bed carbon adsorbers were conducted. Treatment efficiencies were evaluated in terms of the removals of chemical oxygen …

An Empirical Method Of Correlating Compressibility Factors Of Nitrogen - Helium - Hydrocarbon Systems, Terry Wayne Buck

Masters Theses

"Compressibility factors have been taken from previous works by Davis and Taneja for twelve different common oil-field hydrocarbon mixtures which contain at least 2 mole % nitrogen. An effort has been made to show that by using the Benedict-Webb-Rubin Equation of State it is possible to predict compressibility factors using a correlation of error in predicted compressibility factor versus reduced pressure, at different mole % of nitrogen with constant reduced temperatures, if the critical points of the mixtures are known or can be calculated. In the mixtures which contain helium, the only effect of helium seems to be the raising …

A Comparison Of Computer Codes For Fast Neutron Dosimetry By The Foil Technique, Jau Wen Chen

Masters Theses

"A comparison of the major codes currently used for fast neutron dosimetry based on the foil technique has been made. These codes are SAND II, SPECTRA and RDMM. The comparison is based upon the deviation of calculated from-measured activities, the input data decks, the obtained information, and the computer time required. Four sets of data were used to be compared upon the above four viewpoints, the conclusion reached is that the SPECTRA computer code is the most satisfactory for the UMR Reactor fast neutron spectrum"--Abstract, page ii.

A Driver-Assisting Control System, Roger Allen Hayes

Masters Theses

"The material presented here explains the electronics of a magnetic guidance control system. The system is based on magnets embedded in the center of the roadway. If a vehicle passes near a magnet, fluxgate magnetometers sense the presence of the magnets and guidance pulses are developed and processed. The end result is a visual output which indicates the direction the driver must steer the vehicle for proper positioning on the roadway. The paper presents a solution to the detection problem caused by the sensor output being a function of the earth's field as well as the field of the guidance …

A Study Of The Dislocation Instability And Reverse Martensitic Transformation In Fe-Ni System, Chung Lim

Masters Theses

"Since the martensitic reaction is a strain transformation, the transformation of the lattice structure can be induced by an external stresses. This also means that the macroscopic total elastic constant should decrease as the temperature is lowered to M_s on cooling. For the reverse transformation an anomalous decrease of the elastic constant is to be expected as the temperature increases to A_s on heating. In this experiment measurements of the velocity change of an ultrasonic wave in Fe-Ni alloys were carried out for the reverse martensitic transformation. The deviation from the linear relationship of the velocity change as …

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 …

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 …

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 …

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 …