Electrolysis of Aluminum Solutions in a Magnetic Field (open access)

Electrolysis of Aluminum Solutions in a Magnetic Field

This investigation is an attempt to verify the original work done by George Antonoff and Anne Rowley, and to contribute specific data on the action of a magnetic field on aluminum cells. Experiments of the type they have described have been performed and an extensive set of data has been collected. It was thought that if the results of Antonoff and Rowley could be duplicated, further investigation would be warranted. However, the experiments have produced negative results. These results are described in detail in these chapters.
Date: May 1950
Creator: Wood, Charles E.
System: The UNT Digital Library
Nuclear Magnetic Resonance in Hydrated Crystals - Potassium Oxalate Monohydrate (open access)

Nuclear Magnetic Resonance in Hydrated Crystals - Potassium Oxalate Monohydrate

The problem of this study was the measurement of the proton-proton separation in the water molecule of hydration in a single crystal of potassium oxalate monohydrate.
Date: May 1962
Creator: Mason, Charley Mack
System: The UNT Digital Library
Proton Nuclear Magnetic Resonance in Mica (open access)

Proton Nuclear Magnetic Resonance in Mica

The experiments to be described here were undertaken for the purpose of determining, if possible, by NMR techniques whether or not the hydroxyl protons in mica are bound in a regular crystalline array, and, if so, whether or not the hydroxyl protons occur in reasonably isolated pairs as in waters of hydration.
Date: May 1962
Creator: Townsend, Don H.
System: The UNT Digital Library
Electron Transport in Bismuth at Liquid Helium Tempratures (open access)

Electron Transport in Bismuth at Liquid Helium Tempratures

To obtain information on the band structure of bismuth, galvanomagnetic potentials were measured in a single crystal at liquid-helium and liquid-nitrogen temperatures. These measurements were analyzed for information on the different carriers, particularly for the existence of a high-mobility band of holes.
Date: May 1964
Creator: Newell, James M.
System: The UNT Digital Library
The Dielectric Constant of Galvinoxyl (open access)

The Dielectric Constant of Galvinoxyl

The molecules in many substances are know to undergo at characteristic temperatures a change in their rotational freedom in the solid state, signifying either a change in structure of the material of the onset of limited rotation of the molecule about some symmetry axis. The purpose of this research was to determine from dielectric constant measurements over the 100°K-420°K temperature range whether or not the organic free radical galvinoxyl and its diamagnetic parent molecule, dihydroxydiphenylmethane, undergo any such transitions.
Date: May 1968
Creator: Mizell, Michael E.
System: The UNT Digital Library
Cross-Section at 15.6 and 16.1 MeV (open access)

Cross-Section at 15.6 and 16.1 MeV

The intent of this investigation is the determination of the values of the Cs-133 (n,2n)Cs-132 cross-section at neutron energies of 15.6 and 16.1 MeV. Neutrons of this energy are produced with comparative ease by means of the D-T reaction, in which deuterons of energy 500 and 750 keV, respectively, are impingent upon a tritium target.
Date: May 1969
Creator: Pepper, George H.
System: The UNT Digital Library
Cross Section Measurements in Praseodymium-141 as a Function of Neutron Bombarding Energy (open access)

Cross Section Measurements in Praseodymium-141 as a Function of Neutron Bombarding Energy

Using the parallel disk method of activation analysis, the (n,2n) reaction cross section in 141-Pr was measured as a function of neutron energy in the range 15.4 to 18.4 MeV. The bombarding neutrons were produced from the 3-T(d,n)4-He reaction, where the deuterons were accelerated by the 3-MV Van de Graff generator of the North Texas Regional Physics Laboratory in Denton, Texas.
Date: May 1971
Creator: Marsh, Stephen Addison
System: The UNT Digital Library
Phase Shift Determination for Elastic Potential Scattering, Using the IBM 360-50 Computer (open access)

Phase Shift Determination for Elastic Potential Scattering, Using the IBM 360-50 Computer

The primary objective of this paper is to present a computerized method for the extraction of phase shifts from an angular distribution. This was accomplished using a least squares curve fitting routine.
Date: May 1971
Creator: Psencik, James A.
System: The UNT Digital Library
Electrical Conductivity in Thin Films (open access)

Electrical Conductivity in Thin Films

This thesis deals with electrical conductivity in thin films. Classical and quantum size effects in conductivity are discussed including some experimental evidence of quantum size effects. The component conductivity along the applied electric field of a thin film in a transverse magnetic field is developed in a density matrix method.
Date: May 1973
Creator: Meyer, Frederick Otto
System: The UNT Digital Library
Effects of Discharge Tube Geometry on Plasma Ion Oscillations (open access)

Effects of Discharge Tube Geometry on Plasma Ion Oscillations

This study considers the effect, on plasma ion oscillations, of various lengths of discharge tubes as well as various cross sections of discharge tubes. Four different gases were used in generating the plasma. Gas pressure and discharge voltage and current were varied to obtain a large number of signals. A historical survey is given to familiarize the reader with the field. The experimental equipment and procedure used in obtaining data is given. An analysis of the data obtained is presented along with possible explanations for the observed phenomena. Suggestions for future study are made.
Date: May 1975
Creator: Simmons, David Warren
System: The UNT Digital Library
A Technique for Increasing the Optical Strength of Single-Crystal NaCl and KCl Through Temperature Cycling (open access)

A Technique for Increasing the Optical Strength of Single-Crystal NaCl and KCl Through Temperature Cycling

This thesis relates a technique for increasing the optical strength of NaCl and KCl single-crystal samples. The 1.06-μm pulsed laser damage thresholds were increased by factors as large as 4.6 for a bulk NaCl single-crystal sample. The bulk laser damage breakdown threshold (LDBT) of the crystal was measured prior to and after heat treatment at 800*C using a Nd:YAG laser operating at 1.06 μm. Bulk and surface LDBTs were also studied on samples annealed at 400° C. These samples showed differences in damage morphology on both cleaved and polished surfaces, and the cleaved surfaces had improved damage thresholds. However, neither the polished surfaces nor the bulk showed improved threshold at the lower annealing temperature.
Date: May 1983
Creator: Franck, Jerome B. (Jerome Bruce)
System: The UNT Digital Library

Growing carbon nanotubes by chemical vapor deposition technique.

Access: Use of this item is restricted to the UNT Community
Carbon nanotubes were synthesized in the laboratory using chemical vapor deposition at different methane concentration. I found that a methane concentration of 4 sccm was ideal for well recognizable carbon nanotubes. A higher concentration led to fewer nanotube growth and silicon carbide structure. Coating the sample first with Fe(NO3)3 created a catalyst base on the substrate for the nanotube to adhere and grow on.
Date: May 2000
Creator: Rajan, Harihar V.
System: The UNT Digital Library
Application of the Finite Element Method to Some Simple Systems in One and Two Dimensions. (open access)

Application of the Finite Element Method to Some Simple Systems in One and Two Dimensions.

The finite element method (FEM) is reviewed and applied to the one-dimensional eigensystems of the isotropic harmonic oscillator, finite well, infinite well and radial hydrogen atom, and the two-dimensional eigensystems of the isotropic harmonic oscillator and the propagational modes of sound in a rectangular cavity. Computer codes that I developed were introduced and utilized to find accurate results for the FEM eigensolutions. One of the computer codes was modified and applied to the one-dimensional unbound quantum mechanical system of a square barrier potential and also provided accurate results.
Date: May 2002
Creator: Hunnell, Jason C.
System: The UNT Digital Library

Approach to Quantum Information starting from Bell's Inequality (Part I) and Statistical Analysis of Time Series Corresponding to Complex Processes (Part II)

Access: Use of this item is restricted to the UNT Community
I: Quantum information obeys laws that subtly extend those governing classical information, making possible novel effect such as cryptography and quantum computation. Quantum computations are extremely sensitive to disruption by interaction of the computer with its environment, but this problem can be overcome by recently developed quantum versions of classical error-correcting codes and fault-tolerant circuits. Based on these ideas, the purpose of this paper is to provide an approach to quantum information by analyzing and demonstrating Bell's inequality and by discussing the problems related to decoherence and error-correcting. II: The growing need for a better understanding of complex processes has stimulated the development of new and more advanced data analysis techniques. The purpose of this research was to investigate some of the already existing techniques (Hurst's rescaled range and relative dispersion analysis), to develop a software able to process time series with these techniques, and to get familiar with the theory of diffusion processes.
Date: May 2002
Creator: Failla, Roberto
System: The UNT Digital Library
Theoretical Study of Second Harmonic Generation of a Blue Laser at 486 nm Using a BBO Crystal in a Standing Wave Buildup Cavity (open access)

Theoretical Study of Second Harmonic Generation of a Blue Laser at 486 nm Using a BBO Crystal in a Standing Wave Buildup Cavity

For a spectroscopy purpose, we are interested in producing continuous wave (CW) UV laser light at 243 nm with at least 2 mW power. The theory of nonlinear optics suggests that we should be able to produce a desired 2.9 mW of 243 nm light by second harmonic generation (SHG) from a 50 mW blue laser at 486 nm using a BBO crystal in a build up cavity. The most important physical parameters are calculated. A 10 mm Brewster cut BBO crystal can provide phase matching conditions for coupling two ordinary photons at 486 nm and make a secondary beam at 243 nm. The single pass conversion efficiency is calculated not to be enough to generate 2.9 mW of SH light. My investigation shows that a standing wave build up cavity can provide a buildup factor of 94 and an overall conversion efficiency of 5.9% if one use an input coupler mirror with 1.1% transmission at 486 nm.
Date: May 2002
Creator: Khademian, Ali
System: The UNT Digital Library
Precision measurements of the hyperfine structure in the 23P state of 3He. (open access)

Precision measurements of the hyperfine structure in the 23P state of 3He.

The unusually large hyperfine structure splittings in the 23P state of the 3He isotope is measured using electro-optic techniques with high precision laser spectroscopy. Originally designed to probe the fine structure of the 4He atom, this experimental setup along with special modifications I implemented to resolve certain 3He related issues has made possible new high precision hyperfine structure measurements. Discussed are the details of the experimental setup and the modifications, including in depth information necessary to consider while performing these measurements. The results of these hyperfine structure measurements give an order of magnitude improvement in precision over the best previously reported values.
Date: May 2003
Creator: Smiciklas, Marc
System: The UNT Digital Library
Maxwell's Equations from Electrostatics and Einstein's Gravitational Field Equation from Newton's Universal Law of Gravitation Using Tensors (open access)

Maxwell's Equations from Electrostatics and Einstein's Gravitational Field Equation from Newton's Universal Law of Gravitation Using Tensors

Maxwell's equations are obtained from Coulomb's Law using special relativity. For the derivation, tensor analysis is used, charge is assumed to be a conserved scalar, the Lorentz force is assumed to be a pure force, and the principle of superposition is assumed to hold. Einstein's gravitational field equation is obtained from Newton's universal law of gravitation. In order to proceed, the principle of least action for gravity is shown to be equivalent to the maximization of proper time along a geodesic. The conservation of energy and momentum is assumed, which, through the use of the Bianchi identity, results in Einstein's field equation.
Date: May 2004
Creator: Burns, Michael E.
System: The UNT Digital Library
Nonlinear UV Laser Build-up Cavity: An Efficient Design (open access)

Nonlinear UV Laser Build-up Cavity: An Efficient Design

Using the concept of the build-up cavity for second harmonic generation to produce 243nm laser light, an innovative cavity is theoretically explored using a 15mm length CLBO crystal. In order to limit the losses of the cavity, the number of effective optical surfaces is kept to only four and the use of a MgF2 crystal is adopted to separate the harmonic and fundamental laser beam from each other. The cavity is shown to have an expected round trip loss of five tenths of a percent or better, resulting in a conversion efficiency greater than 65%.
Date: May 2009
Creator: Rady, Nicholas Henry
System: The UNT Digital Library