Physical Sciences and Mathematics Commons^™

An Information Theoretic Study Of The Ising Antiferromagnet With Quenched Dilution On A Triangular Lattice, Matthew D. Robinson

Electronic Theses and Dissertations

This investigation applies information theoretic techniques to study the ordering and structure of the Ising antiferromagnet with quenched disorder on a triangular lattice. The pure system shows no phase transition due to the high degree of frustration present. However, when quenched vacancies are introduced randomly into this geometrically frustrated system, a phase transition at finite temperature, to an ordered phase, can arise. If the vacancies are introduced on all three sublattices of the triangular lattice, then a two-dimensional spin-glass transition occurs. If dilution takes place on only one sublattice, then the other two sublattices develop magnetiza- tions below the critical …

Crevassing And Calving Of Glacial Ice, James Patrick Kenneally

Electronic Theses and Dissertations

Calving of ice is a relatively new area of research in the still young field of glaciology. In the short time that calving has been studied, it has been mainly treated as an afterthought, with the predominant mode of thinking being that it will happen so to concern oneself with why is not important. Many studies dealt with observations of calving front positions over time vs. ice velocity in an attempt to quantify the calving rate as the difference between the two, while others have attempted to deduce some empirical relationship between calving rate and variables such as water depth …

Extracting Movement Patterns Using Fuzzy And Neuro-Fuzzy Approaches, Haci Mustafa Palancioglu

Electronic Theses and Dissertations

Several applications generate large volumes of data on movements including vehicle navigation, fleet management, wildlife tracking and in the near future cell phone tracking. Such applications require support to manage the growing volumes of movement data. Understanding how an object moves in space and time is fundamental to the development of an appropriate movement model of the object. Many objects are dynamic and their positions change with time. The ability to reason about the changing positions of moving objects over time thus becomes crucial. Explanations on movements of an object require descriptions of the patterns they exhibit over space and …

Performance Advantages Of Maximum Likelihood Methods In Prbs-Modulated Time-Of-Flight Energy Loss Spectroscopy, Zhongyu Yang

Electronic Theses and Dissertations

This thesis describes the design, experimental performance, and theoretical simulation of a novel time-of-flight analyzer that was integrated into a high resolution electron energy loss spectrometer (TOF-HREELS). First we examined the use of an interleaved comb chopper for chopping a continuous electron beam. Both static and dynamic behaviors were simulated theoretically and measured experimentally, with very good agreement. The finite penetration of the field beyond the plane of the chopper leads to non-ideal chopper response, which is characterized in terms of an "energy corruption" effect and a lead or lag in the time at which the beam responds to the …

Renormalization-Group Studies Of Three Model Systems Far From Equilibrium, Ivan T. Georgiev

Electronic Theses and Dissertations

This thesis describes the development of analytical and computational techniques for systems far from equilibrium and their application to three model systems. Each of the model systems reaches a non-equilibrium steady state and exhibits one or more phase transitions. We first introduce a new position-space renormalization-group approach and illustrate its application using the one-dimensional fully asymmetric exclusion process. We have constructed a recursion relation for the relevant dynamic parameters for this model and have reproduced all of the important critical features of the model, including the exact positions of the critical point and the first and second order phase boundaries. …

Table Of Contents

Journal of the South Carolina Academy of Science

No abstract provided.

President's Message

Journal of the South Carolina Academy of Science

No abstract provided.

Par Mediation Of Thrombin-Induced Effects On Motoneurons, Nadim Salman, Drew Watkins, Kate Hamel, Lakisha Gadsden, Sarah Funderburk, Victoria Turgeon

Journal of the South Carolina Academy of Science

No abstract provided.

Some Notes On Multiplicative Congruential Random Number Generators With Mersenne Prime Modulus 261-1., James Harris

Journal of the South Carolina Academy of Science

No abstract provided.

Embryogenesis In The Japanese Medaka, Oryzias Latipes, Laura Harris Harris, Lisa Sims, Roxann Stachiw

Journal of the South Carolina Academy of Science

No abstract provided.

Critical Thinking And Biology Instruction., David J. Stroup, John L. Frola

Journal of the South Carolina Academy of Science

No abstract provided.

Molecular Dynamics Simulation Of The Order- Disorder Phase Transition In Solid Nano2, Wei-Guo Yin, Chun-Gang Duan, Wai-Ning Mei, Jianjun Liu, Robert W. Smith, John R. Hardy

Physics Faculty Publications

We present molecular dynamics simulations of solid NaNO2 using pair potentials with the rigid-ion model. The crystal potential surface is calculated by using an a priori method which integrates the ab initio calculations with the Gordon-Kim electron gas theory. This approach is carefully examined by using different population analysis methods and comparing the intermolecular interactions resulting from this approach with those from the ab initio Hartree-Fock calculations. Our numerics show that the ferroelectric-paraelectric phase transition in solid NaNO2 is triggered by rotation of the nitrite ions around the crystallographical c axis, in agreement with recent x-ray experiments @Gohda et al., …

Comparison Of The Theoretical And Experimental Band Structure Of Poly (Vinylidene Fluoride) Crystal, Chun-Gang Duan, Wai-Ning Mei, John R. Hardy, Stephen Ducharme, Jaewu Choi, Peter A. Dowben

Physics Faculty Publications

The electronic structure and band symmetries of the ferroelectric phase of poly (vinylidene fluoride) (PVDF) are studied by using the first-principles density-functional method. Our calculated results agree well with the angle-resolved photoemission experiments. We find that the PVDF crystal has an energy gap of about 6 eV at the Γ-point. Large dispersion of the valence band is found only along the chain direction, which is consistent with the quasi-one-dimensional nature of PVDF. In particular, the band symmetries of the valence states deduced theoretically are in good agreement with experiment. Finally, further investigations on the electronic structure of poly(trifluoroethylene) (PTrFE) …

Characterization Of The Interaction Of Gamma Cyclodextrin With Single-Walled Carbon Nanotubes, Gordon Chambers, Clodagh Carroll, Garrett Farrell, Alan Dalton, Mary Mcnamara, Marc In Het Panhuis, Hugh Byrne

Articles

In this study a number of composite-like samples of ç-cyclodextrin and HiPco carbon nanotubes were prepared. The first sample was prepared by a simple grinding procedure, which has been reported to cut HiPco carbon nanotubes. The other samples were obtained via a refluxing procedure analogous to similar studies on other fullerenes and ç-cyclodextrin. The samples were analyzed using absorption and Raman spectroscopy, and differential scanning calorimetry. The results presented show clear evidence of an intermolecular interaction between ç-cyclodextrin and single-walled carbon nanotubes.

Atlases Of Globally-Predicted Small Molecule Data. 1: Internuclear Separation, Jason V. Ileto

Capstone Research Projects

A table of globally-predicted data of internuclear separation is presented, the first of a series on molecular properties. This paper explores a novel frequency compensation of neural network inputs and a new measure of the asymmetry in the globally-predicted data.

Evaluation Of The Influence Of A Thioether Substituent On The Solid State And Solution Properties Of N3S-Ligated Copper(Ii) Complexes, Kyle J. Tubbs, Amy L. Fuller, Brian Bennett, Atta M. Arif, Magdalena Makowska-Grzyska, Lisa M. Berreau

Physics Faculty Research and Publications

Admixture of a N₃S(thioether) ligand having two internal hydrogen bond donors (pbnpa: N-2-(phenylthio)ethyl-N,N-bis-((6-neopentylamino-2-pyridyl)methyl)amine; ebnpa: N-2-(ethylthio)ethyl-N,N-bis-((6-neopentylamino-2-pyridyl)methyl)amine) with equimolar amounts of Cu(ClO₄)₂·6H₂O and NaX (X = Cl⁻, NCO⁻, or N₃⁻) in CH₃OH/H₂O yielded the mononuclear Cu(II) derivatives [(pbnpa)Cu–Cl]ClO₄ (1), [(ebnpa)Cu–Cl]ClO₄ (2), [(pbnpa)Cu–NCO]ClO₄ (3), [(ebnpa)Cu–NCO]ClO₄ (4), [(pbnpa)Cu–N₃]ClO₄ (5), and [(ebnpa)Cu–N₃]ClO₄ (6). Each …

Antiforce Wave Profile For Quasi-Neutral Region, Mostafa Hemmati, Pashupati Adhikari, Jeremy Eckart, Marcus Ilbara

Journal of the Arkansas Academy of Science

This article will present a fluid dynamical theory for breakdown waves in which the direction of electric field force on electrons is in the opposite direction of wave propagation. We will refer to such waves as antiforce waves. The set of equations describing the model will include the equation of particle mass balance, equation of conservation of momentum, and equation of conservation of energy, coupled with Poisson's equation. This model treats the potential wave front as an electron shock wave propagating forward mainly due to the electron impact ionization. The shock front is succeeded by a thin dynamical transition region …

Where To Sit? A Look At Frequency's Effect On Volume Distribution In The Singletary Concert Hall, Matthew Williams

Kaleidoscope

The objective of this project was to find the best seat in the Concert Hall of the Singletary Center for the Arts, here at the University of Kentucky. While subjective factors often determine a patron's favorite place to sit, I decided that an objective scientific approach could prove useful when I, or anyone, next attended a concert. Using only a keyboard amplified by speakers placed at center stage and a sound level monitor, I measured separately the volume of six different frequencies (at intervals of an octave) at twelve different seats throughout the Hall. Defining the best seat as the …

Variation In Thickness Of Copper Films Deposited At Various Distances And Angles Using The Thermionic Vacuum Arc, Tamer Akan, Naci̇ Ekem

Turkish Journal of Physics

The thermionic vacuum arc (TVA) is a new technique for the deposition of thin metallic films. Copper depositions were made on glass substrates placed at various distances and angles with respect to the TVA source. By measuring the thickness of the film on each substrate, the variation in the thickness as a function of the distance and angle with respect to the TVA source is investigated.

A Study Of Direct Two-Proton Transfer Reactions Using Optical Potential Model, A. K. A. R. Al-Farra

Turkish Journal of Physics

^{12}C, ^{26}Mg(^3He,n) reactions have been studied at high bombardment energy with evaluation of the differential cross sections to the ground and the first excited states evaluated in the framework of the exact finite-range Born approximation (DWBA) calculations using the optical model. With the constraint that bound-state interactions have a Thomas-Fermi spin orbit form, different formations of the bound-state wave functions are explored. The calculated angular distributions are found to be in a good agreement with the experimental data. The present DWBA predictions are normalized to give the best overall fits to the data. The extracted spectroscopic factors are reasonable.

First Principles Modeling Of Nanostructures, Serdar Öğüt

Turkish Journal of Physics

Among the various theoretical tools for investigating microscopic material properties, ab initio (first principles) methods based on density functional theory and pseudopotentials have had a very good track record over the last two decades in terms of accuracy, reliability, and efficiency. The application of these methods to nanostructures to investigate their structural, electronic, and optical properties has, however, not been quite straightforward due to the large computational demand and new physics inherent in the nanometer and sub-nanometer size region. One particularly useful extension to overcome the computational demand imposed by localized nanostructures has been the introduction of methods based on …

Us Nuclear Security Cooperation With Russia And Transparency, David W. Hafemeister

Physics

This chapter reviews the efforts of Russia and the United States to conclude agreements on the control or reduction of their inventories of nuclear warheads and military fissile materials. While some of the negotiations attempted to codify arms limitation and reduction measures, others were aimed at constraining the spread of fissile materials and technologies to the non-nuclear weapon states (NNWS). A number of the negotiations had elements of both arms control and non-proliferation.

Most of the monitoring provisions contained in nuclear agreements between Russia and the USA are in the category of transparency measures—those that give confidence that a …

Radiation Transport Modeling Using Parallel Computational Techniques, William Culbreth

Reactor Campaign (TRP)

The Advanced Fuel Cycle Initiative (AFCI) program will rely on the use of accurate calculations and simulations of criticality and shielding for the separation process of the longlived isotopes that present a significant safety hazard in commercial spent fuel. To help design and verify the safety of the separation process, the neutronics code MCNPX will be used to model the distribution of neutron flux within the fuel blanket and to determine the neutron multiplication, k_eff. However, the cross section libraries and computational methods used by MCNPX at these neutron energies still have some uncertainty and will require validation. …

Radiation Transport Modeling Using Parallel Computational Techniques, William Culbreth, Denis Beller

Reactor Campaign (TRP)

The second year of this project involved modeling several aspects of the LANCSE beam experiments:

• Modeling targets of varying diameter in air, in a vacuum, and in the presence of humid air;
• Modeling various proton beam profiles;
• Modeling the effects of off-axis proton beam impingement on the target;
• Modeling the asymmetry introduced by the steel table below the target;
• Modeling the effect of varying ratios of Pb to Bi and the effect of impurities; and
• Modeling the system, including other structures within the test room.

With the experience gained through modeling these systems, the UNLV researchers plan, with the assistance …

Monte Carlo Verification And Modeling Of Lead-Bismuth Spallation Targets, Daniel R. Lowe

Reactor Campaign (TRP)

No abstract provided.

University Of Nevada, Las Vegas Transmutation Research Program Annual Report 2002, Anthony Hechanova, Elizabeth Johnson, Gary Cerefice

Transmutation Research Program Reports (TRP)

The UNLV Transmutation Research Program consists of four components: Program Support, Research Infrastructure Augmentation, International Collaboration, and Student Research.

In the first year of the program, the student research component was supported by the infrastructure augmentation and the program support components. In the second year of the program, the fourth leg of the support system, international collaborations, was added to the research support system.

Corrosion Of Steel By Lead Bismuth Eutectic, John Farley, Allen L. Johnson, Dale L. Perry

Transmutation Sciences Materials (TRP)

Materials for transmuter systems must be able to tolerate high neutron fluxes, great temperatures, and chemical corrosion. For lead bismuth eutectic (LBE) systems, there is an additional challenge in that the corrosive behaviors of materials in LBE are not well understood. Most of the available information on LBE systems has come from the Russians, who have over 80 reactor-years experience with LBE coolant in their Alpha-class submarine reactors. The Russians found that the presence of small amounts of oxygen (on the order of parts per million) in the LBE significantly reduced corrosion. However, a fundamental understanding and verification of its …

Surface Studies Of Corrosion Of Stainless Steel By Lead Bismuth Eutectic, Daniel Koury, Brian D. Hosterman, John Farley, Dale L. Perry, D. Parsons, J. Manzerova, Allen L. Johnson

Transmutation Sciences Materials (TRP)

Why is Lead Bismuth Eutectic Important?

• Changing national security stances have led to reexamination of nuclear waste reprocessing

• Dangerous actinides can be separated and

• Transmuted into safer products, creating a waste form dangerous for only hundreds of years, in addition to the production (up to 1/3 of the original fission energy) of useful energy

• Non-moderating coolants or spallation targets for production of fast neutrons is required for transmutation

• Russian experience with LBE coolants in their nuclear submarine fleet makes LBE an attractive possible transmutation coolant technology

• Corrosion of steel by LBE is an important …

Neutron Multiplicity Measurements Of Target/Blanket Materials, Carter D. Hull, Denis Beller

Transmutation Sciences Physics (TRP)

To optimize the performance of accelerator driven transmutation systems (ADS), engineers will need to design the system to operate with a neutron multiplication factor just below that of a critical, or self-sustaining, system. This design criteria requires particle transport codes that instill the highest level of confidence with minimal uncertainty, because the larger the uncertainties in the codes, the larger the safety margin required in the design and the lower the efficiency of the ADS transmuter. For current design efforts, the MCNPX code is used to determine neutron production and transport for spallation neutron systems.

While providing a very useful …

Development Of Dose Coefficients For Radionuclides Produced In Spallation Targets, Phillip W. Patton, Mark Rudin

Transmutation Sciences Physics (TRP)

Dose coefficients permit simple determination of radiation dose associated with various exposure scenarios, and ultimately permit radiation safety personnel to assess the health risks to workers in a nuclear facility. Specifically, radiation safety personnel use dose coefficients to determine the radiation dose incurred to a tissue or organ system from a given exposure. These parameters are often expressed in terms of Annual Limits on Intake (ALIs) and Derived Air Concentrations (DACs).

Results from this study will be used to produce ALIs and DACs for these rare radionuclides created by spallation target systems that are not included in Federal Guidance Report …