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Electrical Conductivity in Thin Films

Description: 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
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A Study and Critique of the Mean Position Concept in Relativistic Wave Mechanics

Description: The basic concept to be used in studying the question of one-particle interpretations of relativistic wave equations is that of observables and operator representations that are different from the more usual classically motivated observables and representations. In particular, the concept of a mean-position observable will be used to determine to what extent the one-particle "problems" can be resolved.
Date: January 1967
Creator: Gebhart, Hugh David
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Homogeneous Canonical Formalism and Relativistic Wave Equations

Description: This thesis presents a development of classical canonical formalism and the usual transition schema to quantum dynamics. The question of transition from relativistic mechanics to relativistic quantum dynamics is answered by developing a homogeneous formalism which is relativistically invariant. Using this formalism the Klein-Gordon equation is derived as the relativistic analog of the Schroedinger equation. Using this formalism further, a method of generating other relativistic equations (with … more
Date: January 1967
Creator: Jackson, Albert A.
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Quantized Hydrodynamics

Description: The object of this paper is to derive Landau's theory of quantized hydrodynamics from the many-particle Schroedinger equation. Landau's results are obtained, together with an additional term in the Hamiltonian.
Date: August 1972
Creator: Coomer, Grant C.
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A Study of the Celestial Gamma-ray Flux

Description: This thesis is a study of the celestial gamma-ray flux. It reviews several of the proposed mechanisms for producing high energy gamma rays and describes several of the attempts to detect their presence. Also included is a short historical review of the spark chamber, along with a qualitative description of its operation.
Date: June 1967
Creator: Keath, Edwin P. (Edwin Paul), 1938-
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Effects of Discharge Tube Geometry on Plasma Ion Oscillations

Description: 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 al… more
Date: May 1975
Creator: Simmons, David Warren
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Emergence of Complexity from Synchronization and Cooperation

Description: The dynamical origin of complexity is an object of intense debate and, up to moment of writing this manuscript, no unified approach exists as to how it should be properly addressed. This research work adopts the perspective of complexity as characterized by the emergence of non-Poisson renewal processes. In particular I introduce two new complex system models, namely the two-state stochastic clocks and the integrate-and-fire stochastic neurons, and investigate its coupled dynamics in diff… more
Date: May 2008
Creator: Geneston, Elvis L.
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Application of the Wigner Formalism to a Slightly Relativistic Quantum Plasma

Description: A slightly relativistic fermion gas is described by the dynamical theory obtained from the Wigner distribution function. The problem is approached in a self-consistent manner including the two-body Darwin Hamiltonian. The goal is to find the departures from equilibrium and dispersion relations for wave propagation in the gas.
Date: August 1967
Creator: Harper, John H.
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Ballistic Deposition: Global Scaling and Local Time Series.

Description: Complexity can emerge from extremely simple rules. A paradigmatic example of this is the model of ballistic deposition (BD), a simple model of sedimentary rock growth. In two separate Problem-in-Lieu-of Thesis studies, BD was investigated numerically in (1+1)-D on a lattice. Both studies are combined in this document. For problem I, the global interface roughening (IR) process was studied in terms of effective scaling exponents for a generalized BD model. The model used incorporates a tunable p… more
Date: December 2003
Creator: Schwettmann, Arne
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Steady-state and Dynamic Probe Characteristics in a Low-density Plasma

Description: The problem with which this investigation is concerned is that of determining the steady-state and dynamic characteristics of the admittance of a metallic probe immersed in a laboratory plasma which has the low electron densities and low electron temperatures characteristic of the ionospheric plasma. The problem is separated into three related topics: the design and production of the laboratory plasma, the measurement of the steady-state properties of dc and very low frequency probe admittance,… more
Date: December 1970
Creator: Bunting, William David
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Application of the Finite Element Method to Some Simple Systems in One and Two Dimensions.

Description: 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-dime… more
Date: May 2002
Creator: Hunnell, Jason C.
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Anderson Localization in Two-Channel Wires with Correlated Disorder: DNA as an Application

Description: This research studied the Anderson localization of electrons in two-channel wires with correlated disorder and in DNA molecules. It involved an analytical calculation part where the formula for the inverse localization length for electron states in a two-channel wire is derived. It also involved a computational part where the localization length is calculated for some DNA molecules. Electron localization in two-channel wires with correlated disorder was studied using a single-electron tight-bi… more
Date: December 2007
Creator: Bagci, V. M. Kemal
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Surface Segregation in Multi-component Systems: Modeling Binary Ni-Al Alloys Using the BFS Method

Description: Although the study of surface segregation has a great technological importance, the work done in the field was for a long time largely restricted to experimental studies and the theoretical work was neglected. However, recent improvements in both first principles and semi-empirical methods are opening a new era for surface scientists. A method developed by Bozzolo, Ferrante, and Smith (BFS) is particularly suitable for complex systems and several aspects of the computational modeling of surface… more
Date: August 2004
Creator: Kasmi, Azeddine
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Test of Gauge Invariance: Charged Harmonic Oscillator in an Electromagnetic Field

Description: The gauge-invariant formulation of quantum mechanics is compared to the conventional approach for the case of a one-dimensional charged harmonic oscillator in an electromagnetic field in the electric dipole approximation. The probability of finding the oscillator in the ground state or excited states as a function of time is calculated, and the two approaches give different results. On the basis of gauge invariance, the gauge-invariant formulation of quantum mechanics gives the correct probabil… more
Date: August 1980
Creator: Wen, Chang-tai
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Recombination Rate Coefficient Measurements in the Helium Afterglow

Description: This thesis describes a method of determining the recombination rate coefficient experimentally, which does not depend on a specific model of the recombination process. With this method established, results are presented for the recombination rate coefficient measurements at 44.6 Torr.
Date: August 1969
Creator: Wells, William E.
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Complexity as Aging Non-Poisson Renewal Processes

Description: The search for a satisfactory model for complexity, meant as an intermediate condition between total order and total disorder, is still subject of debate in the scientific community. In this dissertation the emergence of non-Poisson renewal processes in several complex systems is investigated. After reviewing the basics of renewal theory, another popular approach to complexity, called modulation, is introduced. I show how these two different approaches, given a suitable choice of the parameter … more
Date: May 2007
Creator: Bianco, Simone
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A Study of Some Biological Effects of Non-Ionizing Electromagnetic Radiation

Description: The experimental studies of this work were done using a microwave cavity spectrometer, Escherichia coli (E-coli) bacteria, and other peripheral equipment. The experiment consists of two steps. First, a general survey of frequencies from 8 GHz to 12 GHz was made. Second, a detailed experiment for specific frequencies selected from the first survey were further studied. Interesting frequency dependent results, such as unusually higher growing or killing rates of E-coli at some frequencies, were f… more
Date: December 1996
Creator: Park, Young C. (Young Chul), 1960-
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Perturbation of renewal processes

Description: Renewal theory began development in the early 1940s, as the need for it in the industrial engineering sub-discipline operations research had risen. In time, the theory found applications in many stochastic processes. In this thesis I investigated the effect of seasonal effects on Poisson and non-Poisson renewal processes in the form of perturbations. It was determined that the statistical analysis methods developed at UNT Center for Nonlinear Science can be used to detect the effects of seasona… more
Date: May 2008
Creator: Akin, Osman Caglar
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The Dynamic Foundation of Fractal Operators.

Description: The fractal operators discussed in this dissertation are introduced in the form originally proposed in an earlier book of the candidate, which proves to be very convenient for physicists, due to its heuristic and intuitive nature. This dissertation proves that these fractal operators are the most convenient tools to address a number of problems in condensed matter, in accordance with the point of view of many other authors, and with the earlier book of the candidate. The microscopic foundation … more
Date: May 2003
Creator: Bologna, Mauro
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Complex Numbers in Quantum Theory

Description: In 1927, Nobel prize winning physicist, E. Schrodinger, in correspondence with Ehrenfest, wrote the following about the new theory: “What is unpleasant here, and indeed directly to be objected to, is the use of complex numbers. Psi is surely fundamentally a real function.” This seemingly simple issue remains unexplained almost ninety years later. In this dissertation I elucidate the physical and theoretical origins of the complex requirement. I identify a freedom/constraint situation encoun… more
Date: August 2015
Creator: Maynard, Glenn
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Polymer Gels: Kinetics, Dynamics Studies and Their Applications as Biomaterials

Description: The polymer gels especially hydrogels have a very special structure and useful features such as unusual volume phase transition, compatibility with biological systems, and sensitivity to environmental stimuli (temperature, pH value, electric field, light and more), which lead to many potential applications in physical and biochemical fields. This research includes: (1) the theoretical and experimental studies of polymer gels on swelling kinetics, spinodal decomposition, and solution convection … more
Date: December 2003
Creator: Wang, Changjie
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Mechanism and the Effect of Microwave-Carbon Nanotube Interaction

Description: A series of experimental results about unusual heating of carbon nanotubes by microwaves is analyzed in this dissertation. Two of vibration types, cantilever type (one end is fixed and the other one end is free), the second type is both ends are fixed, have been studied by other people. A third type of forced vibration of carbon nanotubes under an alternating electromagnetic field is examined in this paper. Heating of carbon nanotubes (CNTs) by microwaves is described in terms of nonlinear dyna… more
Date: December 2005
Creator: Ye, Zhou
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A Comparison of the Problem Solving Ability of Physics and Engineering Students in a Two Year College

Description: The problem with which this study was concerned is a comparison of the problem solving ability of physics and engineering students in a two year college. The purpose of this study was to compare the problem solving ability of physics and engineering students in a two year college and determine whether a difference exists. Data was collected from an instrument administered to twenty-six engineering students and twenty-three physics students as a major examination in their regular courses. The i… more
Date: December 1986
Creator: Martin, John R. (John Robert), 1951-
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The Use of Learning Theory in the Application of Artificial Intelligence to Computer-Assisted Instruction of Physics

Description: It was the purpose of this research, to develop and test an artificially intelligent, learner-based, computer-assisted physics tutor. The resulting expert system is named ARPHY, an acronym for ARtificially intelligent PHYsics tutor. The research was conducted in two phases. In the first phase of the research, the system was constructed using Ausubel's advance organizer as a guiding learning theory. The content of accelerated motion was encoded into this organizer after sub-classification accord… more
Date: August 1985
Creator: Brown, Stephen F. (Stephen Francis)
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