Physical Sciences and Mathematics Commons^™

Effects Of Insectivorous Birds On Tree Growth In The Maurepas Swamp, David M. Fox

LSU Master's Theses

Coastal forests in Louisiana are in decline due to natural and human caused changes in the hydrology of the region. Baldcypress and water tupelo trees have been further stressed by caterpillar herbivory in recent decades. Regeneration of water tupelo is crucial for cavity creation for nesting habitat for secondary cavity nesting bird populations. Insectivorous birds have been shown to decrease insect-caused leaf damage on trees in other ecosystems. Two experiments examining effects of insectivorous birds on tree growth were conducted in degraded areas of the Maurepas Swamp in southeastern Louisiana. In the first experiment, nest boxes were added to study …

Bisections And Reflections: A Geometric Investigation, Carrie Carden, Jessie Penley

Undergraduate Mathematics Day: Past Content

This problem was first introduced as a challenge problem to high school geometry students. After receiving no responses from students, it was then taken to the collegial level. We were given this problem to investigate with the intent of generalizing the results to a broader question. This question being, what happens when we have a polygon with n sides? Before introducing the problem itself, we will recall some basic geometry definitions which will be used throughout this paper.

Methods Of Solution Of Second Order Linear Equations On Time Scales, Ashley Askew

Undergraduate Mathematics Day: Past Content

A time scale, T, is a nonempty, closed subset of the real numbers, R. Several methods of solution exist for second order linear equations on a time scale. An advantage of these methods is that we can obtain solutions on a system comprising of continuous and/or discrete elements. After restricting the time scale to be R, these solutions are equivalent to those obtained using differential equations methods.

A time scale, T, is a nonempty, closed subset of the real numbers, R. Several methods of solution exist for second order linear equations on a time scale. An advantage of these methods …

2006 Vol. 2 Table Of Contents, University Of Dayton. Department Of Mathematics

Undergraduate Mathematics Day: Past Content

No abstract provided.

Mathematical And Numerical Modeling Of Inflammation, Joshua Sullivan, Ivan Yotov

Undergraduate Mathematics Day: Past Content

When the body is attacked by a bacterial infection, it initiates a series of events designed to eradicate the infection while causing minimal damage to the body. Our goal is to investigate the defenses of the organ walls to the spread of infection. To do this we have chosen to model a volume of the body that includes the organ wall, the lumen outside of it and the blood and tissue within it. We have also taken into account the varied responses of the body, and our model includes many interacting agents that are part of the infection and defense …

Adventures With Rubik's Ufo, Bill Higgins

Undergraduate Mathematics Day: Past Content

Enro Rubik invented the puzzle which is now known as Rubik’s Cube in the 1970’s. More than 100 million cubes have been sold worldwide. The mathematics behind solutions to the cube have been extensively studied by mathematicians and puzzle enthusiasts alike. In this article the mathematics behind a solution of the related puzzle known as Rubik’s UFO is analyzed.

An Investigation Of Continued Fractions, Kristi Patton, Sandra Schroeder, Richard Daquila

Undergraduate Mathematics Day: Past Content

The study of continued fractions has produced many interesting and exciting results in number theory and other related fields of mathematics. Continued fractions have been studied for centuries by many famous mathematicians such as Wallis, Euler, Gauss, Lagrange, Ramanujan, Cauchy, and Khinchin. A connection between continued fractions and the Fibonacci sequence can be revealed by examining functional parameters of various rational functions. This work makes use of existing results concerning continued fractions and Mathematica to explore the relationship between continued fractions and rational functions.

Brownian Motion And Its Applications In The Stock Market, Angeliki Ermogenous

Undergraduate Mathematics Day: Past Content

Wilfrid Kendall notes on the complexity of the paths of Brownian motion: If you run Brownian motion in two dimensions for a positive amount of time, it will write your name. The oddness and complexity of Brownian motion reveal a really deep subject in the field of mathematics that cannot be fully understood and explained even until now. The purpose of this paper is to introduce the Brownian motion with its properties and to explain how it is applied in an everyday but totally unpredictable environment like the stock market.

Classifying E-Algebras Over Dedekind Domains, Brendan Goldsmith, R. Gobel

Articles

An R-algebra A is said to be a generalized E-algebra if A is isomorphic to the algebra EndR(A). Generalized E-algebras have been extensively investigated. In this work they are classified ‘modulo cotorsion-free modules’ when the underlying ring R is a Dedekind domain.

Discourse On The Interface Of Matheatics And Physics: A Panel Discussion Sponsored By Dit And The Ria., Brendan Goldsmith

Articles

No abstract available

An Explicit Scheme For Multifluid Magnetohydrodynamics, Stephen O'Sullivan, Turlough Downes

Articles

When modelling astrophysical fluid flows, it is often appropriate to discard the canonical magnetohydrodynamic approximation, thereby freeing the magnetic field to diffuse with respect to the bulk velocity field. As a consequence, however, the induction equation can become problematic to solve via standard explicit techniques. In particular, the Hall diffusion term admits fast-moving whistler waves which can impose a vanishing time-step limit.Within an explicit differencing framework, a multifluid scheme for weakly ionized plasmas is presented which relies upon a new approach to integrating the induction equation efficiently. The first component of this approach is a relatively unknown method of accelerating …

Simulated Domain Wall Dynamics In Magnetic Nanowires, Andrew Kunz

Physics Faculty Research and Publications

The simulated domain wall dynamics in rectangular 10 nm thick, 2000 nm long Permalloy wires of varying width is presented. In the absence of an applied field the static domain wall length is found to be linearly dependent to the width of the nanowire. As magnetic fields of increasing strength are applied along the wire’s long axis, the domain wall motion changes from a uniform reversal to a steplike reversal. The onset of the stepping motion leads to a decrease in the domain wall speed. By continuing to increase the field it is possible to decrease the time between steps …

On-Road Remote Sensing Of Automobile Emissions In The Denver Area: Year 5, January 2005, Gary A. Bishop, Daniel A. Burgard, Donald H. Stedman

Fuel Efficiency Automobile Test Publications

No abstract provided.

On-Road Remote Sensing Of Automobile Emissions In The Phoenix Area: Year 5, November 2004, Gary A. Bishop, Daniel A. Burgard, Donald H. Stedman

Fuel Efficiency Automobile Test Publications

No abstract provided.

The Study Of Carbon Acylation Of Highly Delocalized Enolates Using Catalytic Dmap On 3-Phenyl Benzofuranone Derivatives, Xiguang Zhao

Masters Theses

No abstract provided.

Nonequilibrium Phase Transition On A Randomly Diluted Lattice, Thomas Vojta, Man Young Lee

Physics Faculty Research & Creative Works

We show that the interplay between geometric criticality and dynamical fluctuations leads to a novel universality class of the contact process on a randomly diluted lattice. The nonequilibrium phase transition across the percolation threshold of the lattice is characterized by unconventional activated (exponential) dynamical scaling and strong Griffiths effects. We calculate the critical behavior in two and three space dimensions, and we also relate our results to the recently found infinite-randomness fixed point in the disordered one-dimensional contact process.

Quantum Phase Transitions Of The Diluted O(3) Rotor Model, Thomas Vojta, Rastko Sknepnek

Physics Faculty Research & Creative Works

We study the phase diagram and the quantum phase transitions of a site-diluted two-dimensional O(3) quantum rotor model by means of large-scale Monte Carlo simulations. This system has two quantum phase transitions: a generic one for small dilutions and a percolation transition across the lattice percolation threshold. We determine the critical behavior for both transitions and for the multicritical point that separates them. In contrast to the exotic scaling scenarios found in other random quantum systems, all these transitions are characterized by finite-disorder fixed points with power-law scaling. We relate our findings to a recent classification of phase transitions with …

Comparison Of Classical And Second Quantized Description Of The Dynamic Stark Shift, Martin K. Haas, Ulrich D. Jentschura, Christoph H. Keitel

Physics Faculty Research & Creative Works

We compare the derivation of the dynamic Stark shift of hydrogenic energy levels in a classical framework with an adiabatically damped laser-atom interaction, which is equivalent to the Gell-Mann-Low-Sucher formula, and a treatment based on time-independent perturbation theory, with a second-quantized laser-atom dipole interaction Hamiltonian. Our analysis applies to a laser that excites a two-photon transition in atomic hydrogen or in a hydrogenlike ion with low nuclear charge number. Our comparisons serve to demonstrate why the dynamic Stark shift may be interpreted as a stimulated radiative correction and illustrates connections between the two derivations. The simplest of the derivations is …

Differential Ionization Studies For Positron Impact, Robert D. Dubois, O. G. De Lucio, J. Gavin

Physics Faculty Research & Creative Works

Recent studies of differential ionization by positron impact being performed at the University of Missouri-Rolla are described. Recoil ion-scattered positron and recoil ion-scattered positron-ejected electron coincidences are measured to provide doubly and triply differential ionization data (DDCS and TDCS) for e+ - Ar collisions. the DDCS and TDCS studies are for 750 and 200 eV impact respectively. for the TDCS studies the positron scattering angles are between approximately ± 5° and electrons ejected with energies less than 15 eV and angles between 90° ± 50° with respect to the beam direction are detected. Examples of TDCS data for the scattered …

Complex Symmetric Operators And Applications, Stephan Ramon Garcia, Mihai Putinar

Pomona Faculty Publications and Research

We study a few classes of Hilbert space operators whose matrix representations are complex symmetric with respect to a preferred orthonormal basis. The existence of this additional symmetry has notable implications and, in particular, it explains from a unifying point of view some classical results. We explore applications of this symmetry to Jordan canonical models, self-adjoint extensions of symmetric operators, rank-one unitary perturbations of the compressed shift, Darlington synthesis and matrix-valued inner functions, and free bounded analytic interpolation in the disk.

Cacu3ti4o12: Low-Temperature Synthesis By Pyrolysis Of An Organic Solution, Jianjun Liu, Yucheng Sui, Chun-Gang Duan, Wai-Ning Mei, Robert W. Smith, John R. Hardy

Chemistry Faculty Publications

The giant-dielectric-constant material CaCu3Ti4O12 (CCTO) has been synthesized by pyrolyzing an organic solution containing stoichiometric amounts of the metal cations, which is done at lower temperature and shorter reaction time than the conventional solid-state reaction. A stable solution was prepared by dissolving calcium nitrate, copper(II) nitrate, and titanium(IV) isopropoxide in 2-methoxyethanol. This solution was pyrolyzed and heat-treated to achieve single-phase CCTO. The phases, microstructures, and dielectric properties of intermediate and final samples were characterized by X-ray diffraction, scanning electron microscopy, and dielectric spectroscopy.

Evolutionary Algorithms For Production Scheduling, Pio Fenton

Theses

The permutation with repetition representation is a powerful representation primarily used in the GA-JSSP domain. Recently, attention has shifted from this representation for simple GA and towards JSSP resolution using messy GA. This work returns to the permutation with repetition representation for simple GA with the intention of exploring some previously unexplored aspects. A new 1-point crossover operator is introduced which is shown to be more successful than the current standard operator for this representation. A technique known as morphogenic computation is employed with this representation for the first time and a thorough analysis of its performance is presented. While …

A Contemporary Review Of 1975-1976 Elevated Activity Levels At The Mount Baker Complex, Washington, And Current Community Awareness Of Volcanic Hazards, Janna Juday

WWU Graduate School Collection

This investigation seeks to understand the changes in the associated volcanic and human systems during and after the 1975-1976 sudden thermal events at Mount Baker volcano. Included are reviews of some of the conclusions made by scientists from the U.S. Geological Survey and universities around the U.S. during that event. A questionnaire was also presented to people in communities around the volcano to outline current understanding of volcanic activity and hazards associated with Mount Baker.

The source of the Mount Baker thermal activity in 1975-1976 was never conclusively identified at the time. There appears to have been a small decrease …

Soil Phosphorus Levels In Residential Lawns And Comparisons Among Four Land Uses In Springfield, Missouri, Timothy R. Davis

MSU Graduate Theses

Eutrophication of surface waters due to high phosphorus (P) concentrations is an important water quality concern in Greene County, Missouri. Phosphorus enrichment has been linked to a variety of non-point sources including runoff from both agricultural and urban land uses. Soil P has been shown to be a source of P in runoff. The differences in soil P among different land uses may provide insight into which land use contributes more P in runoff. This study examines the soil composition, geochemistry and total P concentration of surface soil (0-5cm) in four land uses in Greene County, Missouri. The land uses …

Development Of Generalized Index-Removal Models, With Particular Attention To Catchability Issues, Thomas F. Ihde

Dissertations, Theses, and Masters Projects

The index-removal method estimates abundance, exploitation and catchability coefficient, given surveys conducted before and after a known removal. The method assumes a closed population between surveys. Index-removal has seldom been applied due to its strong assumption of constant survey catchabilities. This work generalizes the method to allow multiple years of data to be incorporated, and the assumptions of the original model to be relaxed. If catchability is constant across years, precision can be improved by analyzing multi-year data simultaneously. Two multiple-year models were developed: the first, 1qIR, assumes constant catchability within and among years; the second, 2qIR, allows catchability to …

Diel And Site-Specific Feeding Of Young Striped Bass In A Heterogeneous Nursery Habitat, Sarah C. Muffelman

Dissertations, Theses, and Masters Projects

The Chesapeake Bay spawning stock of striped bass, Morone saxatilis, is considered one of the largest sources of juvenile production along the Atlantic coast and exhibits a high degree of interannual recruitment variability. Year class strength is judged by near-shore seine surveys that cover major tributaries of Chesapeake Bay and survey results are incorporated into annual stock assessments. In these surveys, the contribution of the Rappahannock River (Virginia) to total production is significant. In this system, abundance of juveniles is highest at a single seine site, suggesting that juvenile production may be related to habitat heterogeneity and food availability. To …

Incorporating Space Into Stock Assessments Of Marine Species, John F. Walter

Dissertations, Theses, and Masters Projects

Spatial management of marine resources requires population dynamic parameters in much greater spatial detail than traditional stock assessments provide. This dissertation presents a suite of methods to improve the spatial prediction of population abundance, fishing and natural mortality and to make greater use of commercial catch data. The main objectives of this dissertation are to determine the efficacy of using the vast amount of data collected by on-board observers on commercial vessels in model-based estimation of abundance and to use the spatial autocorrelation to improve resource mapping and abundance estimation. The first paper presents a methodology for improving variogram estimation …

Magnetic Properties Of One-Dimensional Quasiperiodic Co/Pt Multilayers, L. Y. Zhu, Xuemei Cheng, C. L. Chien

Physics Faculty Research and Scholarship

We have fabricated Fibonacci [Co/Pt] multilayers with two constituent Co/Pt bilayers, as well as periodic multilayers of the same Co/Pt bilayers, all of which exhibit perpendicular magnetic anisotropy. Magnetic properties of the quasiperiodic and periodic [Co/Pt] multilayers have been studied macroscopically by vibrating sample magnetometry and microscopically by magnetic force microscopy. The Fibonacci [CoPt] multilayers show enhanced squareness in magnetic hysteresis loops compared to the corresponding periodic [Co/Pt]_n multilayers, due to a smaller density of isolated nucleation sites in the saturation state.

Unusual Magnetization Reversal In [Co/Pt]4 Multilayers With Perpendicular Anisotropy, Xuemei Cheng, V. I. Nikitenko, A. J. Shapiro, R. D. Shull, C. L. Chien

Physics Faculty Research and Scholarship

Unusual magnetization reversal of [Co(4 Å)/Pt(10 Å)]₄ multilayers with perpendicular magnetic anisotropy has been revealed macroscopically by magnetometry measurements and microscopically by magneto-optical Kerr effect microscopy and magnetic force microscopy (MFM) imaging. During the first-order reversal process, the magnetization first decreases, then reaches a plateau, and finally rises back to saturation, corresponding to expanding bubble domains, stationary domains, and fading contrast but unchanged boundary domains, respectively. MFM imaging reveals the existence of many submicron-scaled unreversed channels within the boundary of the “bubble” domains. The magnetization reversal behavior can be accounted for by the evolution of the unusual domain structures …

Cf3 Rotation In 3-(Trifluoromethyl)Phenanthrene. X-Ray Diffraction And Ab Initio Electronic Structure Calculations, Xianlong Wang, Frank B. Mallory, Clelia W. Mallory, Peter A. Beckmann, Arnold L. Rheingold, Michelle M. Francl

Physics Faculty Research and Scholarship

The molecular and crystal structure of 3-(trifluoromethyl)phenanthrene has been determined by X-ray diffraction. The structure of the isolated molecule has been calculated using electronic structure methods at the HF/3-21G, HF/6-31G*, MP2/6-31G* and B3LYP/6-31G* levels. The potential energy surfaces for the rotation of the CF3 group in both the isolated molecule and cluster models for the crystal were computed using electronic structure methods. The barrier height for CF3 rotation in the isolated molecule was calculated to be 0.40 kcal mol-1 at B3LYP/6-311+G**//B3LYP/6-311+G**. The B3LYP/6-31G* calculated CF3 rotational barrier in a 13-molecule cluster based on the X-ray data was found to be …