Physical Sciences and Mathematics Commons^™

Pedogenic Relationships In A Texas Vertisol Climosequence Defined By Geochemical Mass Balance Of Whole Soil And Chemistry Of Iron-Manganese Nodules, Cynthia A. Stiles

Doctoral Dissertations

Climosequence Vertisol profiles derived from the Upper Beaumont Formation in the Gulf Coastal Prairie physiographic province of Texas were examined for geochemical trends ascribed to different precipitation regimes. Mass-balance relationships were utilized for the comparisons. Compositional differences in zirconium (Zr) content between the solum and lower sub-soil precluded it use an immobile strain (volumetric change) indicator. This difference was correlated to sand weight percent (r² = 0.65**). Titanium (Ti) content did not shift correlatively with depth, thus making Ti the preferred strain index element for mass-balance calculations. Depths at which the Zr compositions shifted were not directly related to …

Diagenesis Of Upper Cambrian Mount Simon Sandstone In The Illinois Basin - Microscale Investigation Of Basinal Fluid Migration And Mass Transfer, Zhensheng Chen

Doctoral Dissertations

A series of investigations were conducted to evaluate microscale evidence for basinal fluid migration in the Illinois basin during diagenesis of the Upper Cambrian Mount Simon Sandstone. Samples were examined using transmitted light and cathodoluminescence (CL) petrography, fluid inclusion analysis, and Secondary Ion Mass Spectrometry (SIMS) analysis of ¹⁸O/¹⁶O ratios and trace element compositions. Preliminary investigation of in situ laser ablation ⁴⁰Ar-³⁹Ar age dating techniques on authigenic K-feldspar over growths was also completed.

Two major generations of quartz overgrowths are observed, on the basis of transmitted light and CL petrography and fluid inclusion studies. …

Two Body Dirac Equations And Nucleon Nucleon Scattering Phase Shift Analysis, Bin Liu

Doctoral Dissertations

In this dissertation, the nucleon-nucleon interaction is investigated by using the meson exchange model and the two body Dirac equations of constraint dynamics. This approach to the two body problem has been successfully tested for QED and QCD relativistic bound states. An important question we wish to address is whether or not this approach is also valid in the two body nucleon-nucleon scattering problem. This test involves a number of related problems.

First we must reduce our two body Dirac equations exactly to a Schr¨odinger-like equation. This can be done without making any assumptions or approximations and unlike other relativistic …

Reaction Rate Of 17f(P,Γ)18ne And Its Implications For Nova Nucleosynthesis, Suzanne Parete-Koon

Masters Theses

The rate of the 17F(p,γ)18Ne reaction has a profound effect on the abundances of several isotopes produced during a nova outburst. In 1999 a new rate for 17F(p,γ)18Ne was determined from a measurement of the excitation function for the 1H(17F,p)17F reaction at Oak Ridge National Laboratory's (hereafter ORNL) Holifield Radioactive Ion Beam Facility[1]. This experiment yielded the first definite evidence of a Jπ =3+ state in 18Ne. This state provided a new resonance in the 17F +p capture, which could, depending on its properties, dominate the rate of 17F(p,γ)18Ne at stellar explosive temperatures. The new rate for 17F(p,γ) 18Ne was …

Cross Sections Fall 2001, Department Of Physics And Astronomy

Cross Sections

No abstract provided.

Reversible Melting And Crystallization Of Short And Long Flexible Chain Molecules By Temperature-Modulated Calorimetry, Jeongihm Pak

Doctoral Dissertations

Melting and crystallization of linear, flexible molecules of different lengths was studied by temperature-modulated differential scanning calorimetry, TMDSC. Various techniques for TMDSC with single and multifrequency modulations have been analyzed to optimize the conditions for the present study. The finally chosen method involved a quasi-isothermal mode with a temperature amplitude of 0.5 K and a period of 60 s (frequency = 0.167 Hz). The interpretation of the reversible and irreversible melting was developed by comparison of a variety of different modes of analysis (sinusoidal, sawtooth, and complex sawtooth). The analyzed molecules ranged from n-paraffins, oligomeric fractions of polyethylene and poly(oxyethylene) …

An Individual-Based Approach To Population Dynamics With Applications To Sockeye Salmon And Iteroparous Organisms, Cynthia Moira Krohn

Doctoral Dissertations

Individual-based models have been used to study the population dynamics of semelparous and iteroparous organisms. The rst model, developed for sockeye salmon ( On-corhynchus nerka), was based on the physiology of the individual and incorporated into a population model via a McKendrick-von Foerster type partial di
erential equation. Cycles of population abundance historically found in the Fraser River system were recreated through model simulations. Explanations for the appearance of the cycling were investigated and tested. The results showed that density- and size-dependent mortality were not necessary for cycling to appear, however their inclusion or exclusion in combination with the type …

Adaptive Simulated Annealing: An Alternative Approach For The Error Minimization Of Neural Networks, Yuxing Sun

Masters Theses

This work introduces an alternative algorithm, simulated annealing, to minimize the prediction error from neural networks that traditionally use back-propagation methods. The simulated annealing algorithm stochastically samples the parameter space formed by weights of the neural network until a minimal error is found.

Three problems were investigated in this work: the radiator problem, the spiral problem, and the time series prediction problem. Each of them was examined using the same neural network architecture, i.e., a 2-layer network, and trained by both back-propagation and simulated annealing.

The simulated annealing algorithm consumes longer computation time in searching for the global minimum than …

Quantization Of Maximally Charged Slowly Moving Black Holes, George Siopsis

Physics and Astronomy Publications and Other Works

We discuss the quantization of a system of slowly moving extreme Reissner-Nordström black holes. In the near-horizon limit, this system has been shown to possess an SL(2,R) conformal symmetry. However, the Hamiltonian appears to have no well-defined ground state. This problem can be circumvented by a redefinition of the Hamiltonian due to de Alfaro, Fubini, and Furlan (DFF). We apply the Faddeev-Popov quantization procedure to show that the Hamiltonian with no ground state corresponds to a gauge in which there is an obstruction at the singularities of moduli space requiring a modification of the quantization rules. The …

Time Dependent Density Functional Theory Of Dynamical Response In 3d And 4d Metals, James M. Sullivan

Doctoral Dissertations

Two different but complementary quantum mechanical many-body problems are investigated. These problems include both static and dynamic aspects of the electronelectron interaction in real materials. In Chapter One, we take up the cases of Ag and Ni with a microscopic evaluation of the dielectric function and loss function using the formalism of time dependent density functional theory and all-electron techniques. We address the striking line shapes that have been recently observed via inelastic scattering experiments. The present work reveals three relevant energy scales for excitations in the selected systems. These scales are argued to be generic to a large number …

Generalizations Of The Zero-Divisor Graph Of A Ring, Shane Patrick Redmond

Doctoral Dissertations

Let R be a commutative ring with 1, and let Z(R) denote the set of zero­divisors of R. We define an undirected graph Γ(R) with vertices Z(R)* = Z(R) - {0}, where distinct vertices x and y of R are connected if and only if xy = 0. This graph is called the zero-divisor graph of R. We extend the definition of the zero-divisor graph to a noncommutative ring in several ways. Next, given a commutative ring R and ideal Ι of R, we introduce the notion of an …

Subaerial Paleokarst In The Upper Pennington Formation (Upper Mississippian) Limestones At Leatherwood Ford, Big South Fork, Tennessee, Sara Elizabeth Humbert

Masters Theses

The uppermost Pennington Formation (Mississippian - latest Chesterian) consists of limestone deposits, which, in some areas, contain evidence of paleokarst. A 100 m long continuous outcrop of the upper Pennington Formation was studied at Big South Fork National River and Recreation Area, in Scott County, Tennessee, using both field and petrographic methods, in order to test the hypothesis that the paleokarst is of subaerial origin.

The upper Pennington limestone section was subdivided into 4 depositional units, interpreted as recording sea-level change through the end of the Mississippian. Although there was an overall regression toward the end of the Mississippian, changes …

Cross Sections Spring 2001, Department Of Physics And Astronomy

Cross Sections

No abstract provided.

Utk Geography Newsletter 2 (2001), Department Of Geography

UTK Geography Newsletter

No abstract provided.