Digital Commons Network^™

A Low Frequency Phase Shift Method, Ronnie Carroll Mcmillan

Masters Theses

"The phase shift method of measuring atomic lifetimes is particularly useful because it allows us to make measurements in the steady state mode instead of in the transient mode. High frequency phase shift techniques cause many problems. The equipment, which was designed and built to make low frequency phase shift techniques possible, is shown schematically and discussed. The new experimental techniques employed in our apparatus are a phase multiplier and a unique method of using a photomultiplier as a mixer. In the photomultiplier the final dynode is used as the grid of a triode. The next to the last dynode …

The Use Of Turbulence Energy Equation In Boundary Layer Study, Ro-Chi Tai

Masters Theses

"A turbulent boundary layer problem has been studied analytically and compared with an available experiment in the literature. Correlations of the experimental data were made to investigate the validity of the commonly used empirical relations on turbulent shear stresses. It was found that the model which related the local turbulent shear stress linearly with the local turbulent kinetic energy, as used by Bradshow et. al., appeared to be most reasonable. combining this model with the expression of turbulent viscosity given by Boussinesq, it was then possible to introduce the turbulence-energy equation in addition to the governing equations of continuity and …

Analog Simulation Of Mass Transfer In Droplets With Turbulent Internal Circulation, Jeffrey Tsai-Hwa Kuo

Masters Theses

"The object of this thesis is to simulate the Handlos and Baron Model for mass transfer into droplets by using an iterative analog computer in order to obtain eigenvalue and other parameters in a series solution. The eigenvalues λ_n calculated in this work are compared with the results obtained by Wellek-Skelland using a variational technique and by Patel using numerical approaches on the digital computer. From the analytical series solution, one can calculate the fraction of solute extracted in the droplets as a function of droplet contact time. PACTOLUS, a digital-analog simulator, provides a check on the validity of …

Basic Design Of Mosfet, Four-Phase, Digital Integrated Circuits, Earl Morris Worstell

Masters Theses

"MOSFET is defined as metal oxide semiconductor field-effect transistor. The integrated circuit design relates strictly to logic and switching circuits rather than linear circuits. The design of MOS circuits is primarily one of charge and discharge of stray capacitance through MOSFETS used as switches and active loads. To better take advantage of the possibilities of MOS technology, four-phase (4[phi]) circuitry is developed. It offers higher speeds and lower power while permitting higher circuit density than does static or two-phase (2[phi]) logic. Equations are developed that apply directly to the design of four-phase logic along with examples of circuitry that show …

Experimental Determination Of Dynamic Properties Of Aluminum Including Poisson's Ratio, Terry Lee Holman

Masters Theses

"Two rods of 7075-T651 aluminum are longitudinally impacted to investigate the material's dynamic properties. The test rod, initially at rest, is instrumented with strain gages to record the strain-time history after the impact rod, accelerated to uniform velocity by an air gun launcher, strikes the test rod. A camera records the strain-time pattern displayed on an oscilloscope. The experiment indicates a consistent rise time of approximately 9 µsec. Simple one-dimensional theory correlates well with the experimental data. Compensation is included for the transverse sensitivity of the gages used. The dynamic values for both the modulus of elasticity and Poisson's ratio …

A Study Of The Nucleate Boiling Of Liquid Nitrogen, Liquid Argon, And Liquid Carbon Monoxide From Atmospheric To Near The Critical Pressure, Craig Bauer Johler

Masters Theses

"The nucleate boiling curves of three corresponding states liquids (nitrogen, argon, and carbon monoxide) were analyzed. Each liquid was studied at pressures ranging from atmospheric pressure to near the critical pressure. Saturated liquid boiling was conducted from cylindrical heaters in the horizontal position having diameters of 0.75 inches and lengths of three inches. Liquid nitrogen was boiled from four different gold heat transfer surfaces; argon and carbon monoxide were boiled from the same gold surface. The critical heat flux correlation of Cobb and Park was further verified by agreement with the experimental critical heat flux ratios obtained in this investigation. …

Current Characteristics Of Electrically Sprayed Glycerine, Larry Eugene Stoddard

Masters Theses

"The current carried by electrically-sprayed glycerine was measured, and an empirical relation was obtained for single-jet spraying, given by I = K_IV^0.45M^0.55̇d^-0.18 where V is the electrode voltage, Ṁ the mass-flow rate, and d the electrode spacing, the electrodes being a capillary and collecting plate. Peculiarities of the current waveform, including an exponentially rising envelope, for unstable-jet spraying and multiple-jet spraying, were recorded"--Abstract, page ii.

An Analysis Of A Standardized Digital Circuit Driving A Coaxial Cable, John Pitkin Lappington

Masters Theses

"The expense of developing new circuit designs has forced electronic manufacturers to develop and use multipurpose circuits that can be adapted to fit many requirements. Sometimes this procedure leads to problems that would not have occurred if a circuit, designed to fit a particular application, had been developed. One problem of this type deals with the effect of improperly terminated coaxial cables loading output signals from a digital computer. The unterminated cable reflected the signal back in the computer. This did not affect the putout stage, but the preceeding [sic] driving stage was affected. The degradation of the output of …

A Lyapunov Designed Model-Referenced Control System With Signum Function Adaptive Control Laws, James Steven Epstein

Masters Theses

"An examination of a model-referenced adaptive control system designed to satisfy the requirements of Lyapunov's direct method is made. It is found that each adaptive control loop requires a multiplier for its implementation. A new design is proposed which replaces the multipliers in the control loops by switches, thereby gaining a significant hardware advantage. A first order system designed by the new method is simulated on an analog computer and some refinements are made. The method is then generalized to include nth order systems. The poles of the model, however, are subject to some restrictions. Finally, the problems associated with …

Correlation Of Particulate Theory And Behavior Of Real Soils, Christopher Byron Groves

Masters Theses

"The behavior of granular soils subjected to triaxial stresses can be explained in terms of a combination of elastic deformation and sliding friction. Three sans and a coarse silt at various initial void ratios were tested in drained triaxial compression. Cell pressures were varied between 50 and 1500 psi. Prediction techniques for simulating laboratory data was based on various packings of equal radii spheres. Equilibrium and compatibility equations were used to calculate the principal strains under certain applied stresses. The assumed arrays predicted much smaller strains than those than the soils exhibited. If these strains were subtracted from those observed, …

Effect Of Hydrostatic Pressure On Anelastic Stress Relaxation In A Mixed-Alkali Silicate Glass, Young-Gil (Gilbert Y.) Kim

Masters Theses

"The effect of hydrostatic pressure on the anelastic stress relaxation of a mixed-alkali silicate glass (0.05 Na₂O, 0.95 K₂O, 3 SiO₂) was studied at 75°C between ambient pressure and 6 kbar. The activation volume of diffusion was found to be - 4.2 cm³/mole. It is proposed that a reequilibration of the defect population at pressure gives rise to the negative activation volume of diffusion"--Abstract, page ii.

The Iron-Holmium Binary System And Related Magnetic Properties, Gerald J. Roe

Doctoral Dissertations

"The iron-holmium phase diagram was investigated to determine the alloying behavior of these two metals and to determine the magnetic properties of some of the iron-holmium alloys which formed intermediate phases. The iron-holmium binary system was determined by three experimental techniques, differential thermal analysis (DTA), x-ray diffraction, and metallography. A phase diagram with three eutectic points and four intermediate phases was constructed from the experimental data. The two phases, Ho₆Fe₂₃ and Ho₂Fe₁₇, melted congruently at 1322⁰C and 1343⁰C respectively. HoFe₂ and HoFe₃ melted incongruently at 1288⁰C and 1293⁰C respectively. Neutron diffraction investigations were made on the intermediate phases Ho₆Fe₂₃ and …

Longitudinal Optical Phonon-Plasmon Coupling In Ionic Semiconductors, Thomas Joseph Mcmahon

Doctoral Dissertations

"The coupling of free carriers and lattice vibrational modes is studied in CdS and InSb by room temperature far infrared reflectance measurements. When the free carrier concentration is such that the plasma frequency is at or near the longitudinal optical mode frequency it is shown that while the transverse modes remain fixed, the longitudinal modes mix with the plasma mode and are shifted in a manner similar to that described by Varga in 1965. Using the dielectric function for the coupled system permits the determination of electron effective masses by reflectance measurements with lattice effects excluded. This method allows one …

Improvement In Target Detection With A Frequency Agile Pulsed Non-Coherent Radar, Kenneth Lee Horn

Doctoral Dissertations

"Frequency agile tracking radars have received considerable attention in the literature. Frequency agility is useful in reducing target scintillations, thereby reducing tracking errors under certain conditions. However, little attention has been devoted to the improvement that can be expected in target detection with a frequency agile radar. In the past, complete pulse-to-pulse decorrelation of the target returns has been assumed for all of the analyses concerning target detection with frequency agile radars. This assumption always implies a transmitter with a large bandwidth.

This dissertation analyses a pulsed non-coherent frequency agile radar applied to Swerling's Case I target. The target model …

Dynamic Response Of Circular Plates To Transient And Harmonic Transverse Loads Including The Effect Of Transverse Shear And Rotary Inertia, Perakatte Joseph George

Doctoral Dissertations

"Using an improved theory of plate vibration suggested by R. D. Mindlin which takes into account the effects of transverse shear and rotary inertia, free and forced transverse vibrations of uniform circular plates are studied and the results compared with those obtained using the classical theory of plate vibration. The governing equations are developed in polar coordinates using the equations of elasticity. Frequency equations for axisymmetric and antisymmetric vibrations are derived for solid circular plates under different boundary conditions and for an annular plate rigidly mounted on a shaft. The response of plates to different types of rapidly applied axisymmetric …

A Method For Determining Transient Stability In Power Systems, Charles A. Gross

Doctoral Dissertations

"Given a three phase ac power system consisting of synchronous alternators interconnected by transmission lines and other items of electrical transmission equipment, a method is presented which determines the stability of the system when subjected to a three phase symmetrical fault, and to the subsequent clearing of the fault. It is inherent in the method that an estimation of system stability, assuming an instantaneous clearing of the fault, is available. The critical clearing time is therefore determined. The effect of a speed control loop on the system's largest machine is investigated. The method is applied to two, three, four, and …

A Theoretical Study On The Interpretation Of Resistivity Sounding Data Measured By The Wenner Electrode System, Siew Hung Chan

Doctoral Dissertations

"This thesis deals with a theoretical study on the interpretation of resistivity sounding data measured by the Wenner electrode system. The objectives of this investigation are twofold: (i) to derive from the apparent resistivity data some suitable functions from which the resistivity and thickness of each member of the sequence of layers composing the earth may be determined, and (ii) to devise suitable methods for analyzing the resulting functions. In this investigation it is shown that the solution of the boundary value problem associated with an n-layered earth model leads to an integral equation for the Wenner electrode system. This …

A.C. Hall Effect Measurements On Very High Resistivity Materials Exhibiting Electrode Polarization, James Dale Boyd

Doctoral Dissertations

"A variable frequency, a.c. Hall effect measurement technique has been designed for mobility studies in very high resistivity (>10⁹ ohm·cm) materials exhibiting electrode space charge polarization effects. It incorporates a neutralized input capacitance preamplifier detector which reduces the total input shunting capacitance, including the sample interelectrode capacitances, to a very low, definable value (<0.1 pf) and thereby provides very high and well defined a.c. detector input impedances (4 x 10⁹ and 7 x 10⁹ ohms at 600 and 200 Hz, respectively). Lumped parameter equivalent circuits have been defined to approximate the electrical behavior of sample materials in the measurement configuration. These equivalent circuits, together with independent measurements of the detector input and sample impedances, allow one to correct the detected Hall voltage and obtain the true value from which mobility data may be derived. The validity of these circuits has been established by independent a.c. and d.c. measurements on photoconductive CdS (dark resistivity >10¹⁰ ohm·cm) which exhibited maximum differences of less than 4%. The existing literature has been critically reviewed and the measurement criteria established by this study have been applied to resolve differences in reported data and to suggest improvements in the resolution of previously employed experimental …

Calorimetry Of Room Temperature Deformed Copper, George Juri Filatovs

Doctoral Dissertations

"An adiabatic anisothermal differential calorimeter for the study of room temperature deformed 99.999% pure copper has been constructed. An annealed and a deformed specimen were heated at a constant rate in adiabatic surroundings and the differences in energy released between samples was obtained. The control circuits were automatic. Deformation was by elongation ranging from 12 to 40%, and the corresponding energy found was from 1.9 to 5.3 calories/gram-atom. No recovery energy was found. The results obtained generally agree with published results and, in particular, verify Gordon's isothermal annealing results. It is proposed that the criteria for the presence of recovery …

Diffusion Of Iron And Cobalt In Nickel Single Crystals, Charles Frederick Heuer

Doctoral Dissertations

"Diffusion coefficients of iron-59 in nickel have been determined in the temperature range 815°C to 1200°C. The temperature dependence can be represented by an Arrhenius type relationship,...The effect of the isotopic mass on the diffusion coefficient of cobalt in nickel has also been investigated. The isotope effect parameter, E, was found to vary from .26 to .84 over the temperature range 970.5°C to 1200°C. Both results are consistent with the single vacancy mechanism of diffusion. No evidence of divacancy contributions to the mass transport has been found"--Abstract, Page i.

Grain Boundary Self-Diffusion In Sodium Chloride, Kenneth Ray Riggs

Doctoral Dissertations

"The diffusion of ²²sodium and ³⁶chlorine along tilt and twist grain boundaries in pure and calcium chloride doped sodium chloride bicrystals was investigated. No enhanced diffusion of ²²sodium along the grain boundaries was observed. Between 400°C and 500°C the chlorine grain boundary diffusion parameter, D'Δ, is described by D'Δ = (D'Δ)₀exp (-Q_b/kT), where (D'Δ)₀ is approximately 10⁻⁷ cm³/sec and Qb is 1.15 ± .30 eV. The grain boundary angle, the grain boundary character (tilt or twist), and the calcium chloride concentration appear to have no pronounced effect upon the observed chlorine grain boundary diffusion. The ionic movement …

Low-Lying Levels In Some Spherical And Rotational Nuclides By Coulomb Excitation And Radiative Capture Of Thermal Neutrons, Donald Allan Mcclure

Doctoral Dissertations

"The work presented in this dissertation was performed in order to obtain additional information on the level schemes and decay properties of several nuclei in an attempt to explain the observations in terms of an applicable nuclear model. Various nuclear models are discussed in Section II. A general review from the classical point of view of the Coulomb excitation reaction is discussed in Section III and the thermal-neutron-capture reaction is outlined in Section IV. The experimental equipment and procedure is discussed in Section V in which the ramper method of energy determination is outlined. This method allows the measurement of …

MöSsbauer Effect Studies Of Ferroelectric Phase Transitions In The Pbzro₃ - Pbtio₃ - Bifeo₃ Ternary System, James P. Canner

Doctoral Dissertations

"The Mössbauer Effect was used to measure the phase transitions in the following ferroelectric compounds: 95% PbZ4₀.₈Ti₀.₂ - 5% BiFeO₃ [and] 95% PbZ4₀.₇Ti₀.₃ - 5% BiFeO₃ and in the antiferroelectric compound: 95% PbZrO₃ - 5% BiFeO₃. The parameters obtained were the area under the resonance peak, the isomer shift, and the electric quadrupole splitting, all as a function of temperature. The ionicity, electric field gradient, and Debye temperature were determined for room temperature. The data are discussed in terms of the lattice vibration model of ferroelectrics and antiferroelectrics, and the structural phase transitions as recently defined for these compounds. The …

Noble Gases: A Record Of The Early Solar System, E. C. Alexander

Doctoral Dissertations

"Analyses of the noble gases in samples of iron meteorites are presented which indicate the following: 1. The inclusions of iron meteorites contain noble gases with a wide range of isotopic compositions. 2. The noble gas concentration and isotopic anomalies arc often grossly inhomogeneously distributed within a given inclusion and vary from inclusion to inclusion in a meteorite. 3. Silicate inclusions appear to be the most promising samples for I-Xe and Pu-Xe dating. 4. Graphite and troilite in addition to the silicate inclusion contain significant radiogenic ¹²⁹Xe anomalies. 5. The total I-Xe (and in the case of Toluca silicates total …

Phase Equilibria And Thermodynamic Studies In The System Ca0-Fe0-Fe₂0₃₋Si0₂, Muharrem Timucin

Doctoral Dissertations

"A study of phase relations and thermodynamic properties of phases in the system CaO-FeO-Fe₂O₃-SiO₂ was conducted at 1450°C and 1550°C. The region of stability of the different phases was determined by microscopic examination of the specimens. The thermodynamic properties of liquid were determined by analyses of quenched samples equilibrated at oxygen pressures from about 10⁻¹¹ to 1 atm. Isothermal phase diagrams were constructed from data for 0, 5, 10, 20, and 30 weight percent silica sections of the CaO-FeO-Fe₂O₃-SiO₂ system, and the effect of temperature and increased silica additions on the oxygen solubility of the liquid oxides was measured. Multicomponent …

Statistical Inferences For Location And Scale Parameter Distributions, Robert Henry Dumonceaux

Doctoral Dissertations

"The problem of discriminating between two location and scale parameter distributions is investigated. A general test based on a ratio of likelihoods is presented. A test based on a Pearson Goodness of Fit statistic is also considered. Tables are given for discriminating between the normal and exponential, the normal and double exponential, the normal and extreme value, and also between the normal and logistic. For location and scale parameter distributions, two-sided tolerance limits are shown to always be obtainable by Monte Carlo simulation. A method for obtaining confidence intervals on the reliability at a fixed time t is also given. …

Statistical Inferences For The Generalized Gamma Distribution, Harold Walter Hager

Doctoral Dissertations

"Procedures for handling statistical problems with nuisance parameters are considered with special reference to problems in the three parameter generalized gamma distribution. Maximum likelihood estimation of the parameters of this density has been investigated. Properties of these estimates are established which make it possible to make inferences about the parameters. Discrimination between various models for life testing problems is discussed and the robustness of the Weibull model is advanced. The question of the existence of the maximum likelihood estimates of the parameters for all samples is raised. Empiric evidence is presented indicating that they may not exist for all small …

The Statistics Of Finite, One Dimensional Lattice Fluids, John Roger Glaese

Doctoral Dissertations

"A one dimensional lattice fluid in which particles are allowed to assume only discrete positions is proposed. Particles are free to move from one lattice site to another interacting through a variety of potentials, including the Lennard-Jones type. The model allows the partition function to be evaluated as a discrete sum over the allowable configurations. Both the canonical ensemble and grand ensemble are treated by computer and a third, the pressure ensemble, is considered and shown to be useful in the theoretical treatment of lattice systems. The thermodynamic behavior of various systems is investigated in both the canonical and grand …

X-Ray Determination Of Lattice Parameters And Thermal Expansion Coefficients Of Aluminum, Silver And Molybdenum At Cryogenic Temperatures, Claude Lowell Woodard

Doctoral Dissertations

"A multiple exposure back reflection diffraction camera was designed to mount on the vacuum jacket of a pressurized helium gas "Cryomite". With this design it is possible to obtain six diffraction exposures on a single film at any temperature in the range of 180 to 25°K. temperatures within this range are reached in short intervals and exposure periods are less than 30 minutes in a 2.875 inch (73.03 mm) diameter camera. Some of the advantages of this design are; direct measurements, multiple exposures on a single film, short exposures, direct compensation of film length changes due to evacuation or processing …

Turbulence Measurements In Drag Reducing Flow, Jorge Mario Rodriguez

Doctoral Dissertations

"Studies of the frequency response of hot-film wedge probes in viscoelastic fluids established their reliability as measuring devices and demonstrated that the objections raised by Metzner and Astarita (77) are not valid for wedge probes. The structure of turbulence in drag reducing soap and polymer solutions was studied using a hot-film wedge probe. Intensity of turbulence measurements in drag reducing fluids indicate that the structure of trubulence is strongly dependent on the condition of the solution. Rates of energy dissipation calculated at the center of the tube indicate that there is an increase in the rate of energy dissipated in …