Digital Commons Network^™

Epimorphisms Of Frames, James J. Madden, Andrew Molitor

Faculty Publications

No abstract provided.

Theory Of An Atomic Beam Splitter Based On Velocity-Tuned Resonances, Scott Glasgow, P. Meystre, M. Wilkens, E. M. Wright

Faculty Publications

We develop the theory of an atomic beam splitter in which a monoenergetic beam of two-level atoms is incident normally to a classical standing-wave light field. The incident atomic wave function can be split into two coherent components with transverse momenta ±(2n + 1)fzk using velocity-tuned resonances, where n is the order of the resonance. We discuss the cases of zero- and first-order resonances in detail, and show that the velocity-tuned resonances are renormalized due to a high-frequency Stark shift. Numerical results that display the effects of a finite momentum spread in the incident atomic beam are presented.

The Analysis Of A Model For Wave Motion In A Liquid Semiconductor: Boundary Interaction And Variable Conductivity, William V. Smith

Faculty Publications

The theory of conducting fluids in relative motion with small conductivity is studied with a model including the Maxwell displacement current. The model is linearized, and the interaction of waves with a plane boundary in three space is studied for two orientations of the external magnetic field. It is found that two families of boundary conditions preserve energy in one orientation (external field orthogonal to the boundary), while in the other (external field parallel to the boundary) only one condition exists which preserves energy. It is shown that generalized Fourier transforms exist, generated from the generalized eigenfunction expansions. Further, it …

Simultaneous Light And Radial Velocity Curve Solutions For U Cephei, J. B. Rafert, N. L. Markworth

Faculty Publications

The light-curve synthesis approach of Wilson & Devinney has been used to solve simultaneously light and radial velocity curves of the Algol-type eclipsing binary star U Cephei. We have performed eight new differential corrections solutions using the photometric data of Markworth and the radial velocity data of Batten to obtain a consistent set of orbital and astrophysical parameters for the light and velocity curves of this famous system. We find U Cephei to be best modeled using the semidetached (mode 5) system geometry of the Wilson & Devinney program, with a primary rotating at about 5.2 times its synchronous rate, …

Nonequilibrium Processes In Polymers Undergoing Interchange Reactions. Part 2: Reaction-Diffusion Processes, Alejandro Garcia, J. Pojman, D. Kondepudi, C. Van De Broeck

Faculty Publications

A reactiodffusion system of polymers undergoing interchange reactions is studied. The equation that describes the dynamics of the system is similar to the Boltzmann equation for a gas of hard spheres. We consider a one-dimensionsl system in which the average length and the concentrations at the boundaries are fixed. The resulting steady states are obtained analytically and with numerical integration of equations obtained by using a local equilibrium approximation. Monte Carlo simulations of experimentally realizable conditions were performed and compared. The results reveal a nonlinear distribution of molecular concentration and mass. The entropy of the polymer distributions is calculated as …

Determination Of Rate Distributions From Kinetic Experiments, Todd B. Sauke, P. J. Steinback, K. Chu, H. Frauenfelder, J. B. Johnson, D. C. Lamb, G. U. Nienhaus, R. D. Young

Faculty Publications

Rate processes in proteins are often not adequately described by simple exponential kinetics. Instead of modeling the kinetics in the time domain, it can be advantageous to perform a numerical inversion leading to a rate distribution function f(lambda). The features observed in f(lambda) (number, positions, and shapes of peaks) can then be interpreted. We discuss different numerical techniques for obtaining rate distribution functions, with special emphasis on the maximum entropy method. Examples are given for the application of these techniques to flash photolysis data of heme proteins.

X-Ray Study Of The Crystallization Processes In Amorphous (Zro. 64ni0. 36) 1-Xalx Alloys. [Abstract], W. D. Bruton, T. O. Callaway, Richard H. Langley, B. H. Zhang, D. G. Naugle

Faculty Publications

The short range order in (Zr_0.64Ni_0.36)_1−xAl_x metallic glasses for values of x between 0 and 0.25 was investigated using X-ray diffraction. X-ray intensity patterns and the derived structural functions for the as-quenched samples differed only slightly with the change in aluminum concentration, suggesting that the addition of aluminum does not significantly alter the relative coordination of the zirconium and nickel atoms. Only the first two alloys in the series (x = 0, 0.05) exhibited multiple transitions in the DSC thermograms. The intermediate phase for the x = 0.05 alloy has an …

Fusiform Rust Incidence In Loblolly And Slash Pine Plantations In East Texas, T.G. Gregoire, J. David Lenhart, A Arabatzis

Faculty Publications

A method to predict the incidence of fusiform rust (Cronartium quercuum [Berk.] Miyabe ex Shirai f. sp.

fusiforme) in unthinned loblolly (Pinus taeda L.) and slash pine (Pinus elliotti Englem.) plantations located on non-oldfields in East Texas is presented. In addition, procedures are described to estimate changes in rust incidence over time as: 1. A rust-free tree remains rust free, develops stem or branch galls, or dies. 2. A tree with branch galls remains with branch galls only, develops stem galls, or dies. 3. A tree with stem galls remains with stem galls, or dies. Multinomial logistic regression models utilizing …

Site Index Curves For Loblolly And Slash Pine Plantations In The Post Oak Belt Of East Texas, W. D. Hacker, M. Victor Bilan

Faculty Publications

Stem analysis data collected from dominant and codominant trees growing in loblolly (Pinus taeda L.) and slash pine (Pinus elliottii Engelm.) plantations were used to develop site index curves. These data were collected from loblolly and slash pine plantations growing in the Post Oak Belt of East Texas. The height prediction curves were based on the Chapman-Richards function and will provide an indication of site productivity based on plantation age. South. J. Appl. For. 15(2):97-100.

Virginia And The Ratification Of The Bill Of Rights, J. Gordon Hylton

Faculty Publications

No abstract provided.

A Characterization Of White Noise Test Functionals, H. H. Kuo, J. Potthoff, L. Streit

Faculty Publications

No abstract provided.

Attainable Sets And One-Parameter Semigroups Of Sets, I. Chon, J. D. Lawson

Faculty Publications

No abstract provided.

Some Extremal Connectivity Results For Matroids, Safwan Akkari, James Oxley

Faculty Publications

Let n be an integer exceeding one and M be a matroid having at least n + 2 elements. In this paper, we prove that every n-element subset X of E(M) is in an (n + 1)-element circuit if and only if (i) for every such subset, M X is disconnected, and (ii) for every subset Y with at most n elements, M Y is connected. Various extensions and consequences of this result are also derived including characterizations in terms of connectivity of the 4-point line and of Murty's Sylvester matroids. The former is a result of Seymour. © 1991.

D-Harmonic Distributions And Global Hypoellipticity On Nilmanifolds, Jacek M. Cygan, Leonard F. Richardson

Faculty Publications

Let M = Γ\N be a compact nilmanifold. A system of differential operators D1, …, Dk on M is globally hypoelliptic (GH) if when D1f = g1,…, Dkf=gk with f ∈ D’ (M), g1, …, gk ∈ C∞ (M) then f ∈ C∞ (M). Let X1, …, Xk be real vector fields on M induced by the Lie algebra N of N. We study the relationships between (GH) of the system X1, …, Xk on M, (GH) of the operator D = X12 + … + Xk2, the constancy of D-harmonic distributions on M, and related algebraic conditions on X1, …

Distributional Solutions Of The Wiener-Hopf Integral And Integro-Differential Equations, R. Estrada, R. P. Kanwal

Faculty Publications

We present the theory and technique for obtaining the distributional solutions for the Wiener-Hopf integral and integro-differential equations. This is achieved by identifying a class of kernels for which these equations are well defined and are of the Fredholm type. Consequently, the associated operators and their images are of finite dimensions. Furthermore, we define the operators in such a way that the corresponding equations hold at the end points; otherwise, the equations are usually ill-behaved. We illustrate our analysis with the help of various examples. © 1991, Rocky Mountain Mathematics Consortium. All Rights Reserved.

A Monte Carlo Study Of Rainfall Sampling Effect On A Distributed Catchment Model, Witold F. Krajewski, Venkataraman Lakshmi, Konstantine P. Georgakakos, Subhash C. Jain

Faculty Publications

A Monte Carlo study of a physically based distributed-parameter hydrologic model is described. The catchment model simulates overland flow and streamflow, and it is based on the kinematic wave concept. Soil Conservation Service curves are used to model rainfall excess within the basin. The model was applied to the Ralston Creek watershed, a small (7.5 km²) rural catchment in eastern Iowa. Sensitivity of the model response with respect to rainfall-input spatial and temporal sampling density was investigated. The input data were generated by a space-time stochastic model of rainfall. The generated rainfall fields were sampled by the varied-density …

The "Assaultive Jurisprudence": The Free Speech Critique Of Robert Nagle’S Constitutional Cultures, David Day

Faculty Publications

No abstract provided.

Missing Evidence, Dale A. Nance

Faculty Publications

Given the nature of my enterprise, I resist stating a specific thesis. Nevertheless, for the reader who wants an organizing or motivating principle, I offer the following two recurrent themes. First, I want to examine the relationship of traditional admissibility rules to the problem of missing evidence and to other forms of juridical response to that problem. The reason for this interest will be explained in the next section. Second, I want to investigate, as we proceed, the extent to which the regulation of proof, evidence law broadly conceived, is instrumentally related to accuracy or truth seeking, and the extent …

Structure And Optical Characterization Of Znxcd1-Xte Thin Films Prepared By The Close Spaced Vapor Transport Method, David D. Allred, Jesus González-Hernández, O. Zelaya, J. G. Mendoza-Alverez, E. López-Cruz, D. A. Pawlik

Faculty Publications

Zinc cadmium telluride (ZnxCd1-xTe) solid solution films with 0≤x≤0.12 were deposited by the close spaced vapor transport method and characterized using photoluminescence, x-ray diffraction, and scanning electron microscopy. The two former techniques indicate that films with high crystalline quality can be prepared with moderate substrate temperatures and low argon pressures. Under these conditions deposition rates of up to 1000 Å/s are achieved and Zn concentration in the film is the same as that of the source. The electron micrographs show grain sizes comparable to the film thickness.

The Transmittances Of Thin Polymer Films And Their Suitability As A Supportive Substrate For A Soft X-Ray Solar Filter, Memorie Williams, Evan Hansen, A. Reyes-Mena, David D. Allred

Faculty Publications

This paper discusses soft x-ray filter designs for the Brigham Young University "Goldhelox Project". Three polymers intended for use as a supportive substrate for a soft x-ray solar filter, having a passband centered at 171 angstroms are examined. The use of polymer substrates is examined because of vibrational and mechanical stresses associated with the shuttle launch, preventing the use of a free standing filter, and because of Goldhelox's special need to locate the filter near the imaging plane. The uniform consistency of a polymer support will prevent any imaging of the filter support structure, as would occur if a traditional …

Impossibility, Subjective Probability And Punishment For Attempts, David D. Friedman

Faculty Publications

No abstract provided.

A Fixed Point Property For The Lorentz Space Lp,1(Μ), N L. Carothers, S J. Dilworth, C J. Lennard, D A. Trautman

Faculty Publications

No abstract provided.

A Mathematical Model Of A Sealed Nickel-Cadmium Battery, Deyuan Fan, Ralph E. White

Faculty Publications

A mathematical model for the charge and discharge of a sealed nickel-cadmium (Ni-Cd) battery is presented. The model is used to study the effect of transport properties of the electrolyte and kinetic parameters of the electrode reactions on the cell performance during the charge and discharge period. The model can also be used to demonstrate the changes of cell performance during cycling. Some comparisons between model predictions and experimental results indicate that the model predictions appear to fit the experimental data well. Sensitivity analyses illustrate that the sealed nickel-cadmium battery operates under activation control. It is also shown theoretically that …

Modification Of Newman's Band(J) Subroutine To Multi-Region Systems Containing Interior Boundaries: Mband, D. Fan, Ralph E. White

Faculty Publications

Newman's BAND(J) subroutine, which has been used widely to solve models of various electrochemical systems, is extended to solve a system of coupled, ordinary differential equations with interior boundary conditions. A set of coupled, linear ordinary differential equations is used to demonstrate the solution procedure. The results show that the extended technique has the same accuracy as that of using pentadiagonal BAND(J), but the execution speed is about five times faster than that of pentadiagonal BAND(J). Using sparse matrix solver Y12MAF to solve the same set of equations takes even longer time than pentadiagonal BAND(J).

Novel Chemical Preparative Route For Semiconducting Mose2 Thin Films, K. C. Mandal, O. Savadogo

Faculty Publications

No abstract provided.

A Mathematical Model Of Electrochemical Reactions Coupled With Homogeneous Chemical Reactions, Ken-Ming Yen, Taewhan Yeu, Ralph E. White

Faculty Publications

The zinc/bromine (Zn/Br2) flow battery has received considerable
attention in recent years [e.g., (2-4)]. Although it
is agreed that the solution chemistry is important in the
system, most of the work that has been done is concentrated
on the design variables. In this note the basic mass
transfer-solution and surface kinetics are studied to furnish
a better understanding of the system.

Current Distribution In A Horizon® Lead-Acid Battery During Discharge, Z. Mao, Ralph E. White, B. Jay

Faculty Publications

A simple mathematical model is presented and used to analyze the potential and current distributions in a HORIZON® sealed lead-acid battery. It was found that an increase in the thickness of an electrode would not enhance the discharge rate of that electrode; instead, it causes the transfer current distribution to be less uniform in the electrode. Also, the ohmic drop across the separator would decrease with a decrease in the thickness of the separator more rapidly when the thickness is small than when it is large. In addition, it was found that efficient high-capacity, high-rate electrodes must consider the electrode …

Electrochemical Characterization Of Electronically Conductive Polypyrrole On Cyclic Voltammograms, Taewhan Yeu, Ken-Ming Yin, Jose Carbajal, Ralph E. White

Faculty Publications

Experimental and theoretical cyclic voltammograms for electronically conducting polypyrrole film are obtained from the identical conditions and compared to each other to characterize electrochemical behavior of the polymer. A comparison of the simulated and experimental cyclic yoltammograms shows quantitative agreement. The profiles of the dependent variables show that the switching process is governed by the availability of the counter ion to the polypyrrole electrode and the amount of electroactive sites. Sensitivity analysis shows that the double layer effects have more influence in the cyclic voltammograms than the electrokinetic effects.

A Mathematical Model Of The Self-Discharge Of A Ni-H2 Battery, Z. Mao, Ralph E. White

Faculty Publications

A simple mathematical model is presented and used to characterize the self-discharge of a nickel oxyhydroxide(NiOOH) electrode in a hydrogen environment. This model includes diffusion of dissolved hydrogen in an electrolyte film which covers a flooded electrode, electrochemical oxidation of hydrogen, reduction of nickel oxyhydroxide, and changes of surface area and of porosity of the electrode during the self-discharge process. Although the self-discharge process is complicated, the predictions of the model are consistent with experimental results reported in the literature, which include linear relationships between the logarithm of hydrogen pressure and time and between the logarithm of the capacity remaining …

A Mathematical Model Of A Hydrogen/Oxygen Alkaline Fuel Cell, Michael C. Kimble, Ralph E. White

Faculty Publications

A mathematical model of a hydrogen/oxygen alkaline fuel cell is presented that can be used to predict polarization behavior under various potential loads. The model describes the phenomena occurring in the solid, liquid, and gaseous phases of the anode, separator, and cathode regions, assuming a macrohomogeneous, three-phase porous electrode structure. The model calculates the spatial variation of the partial pressures of oxygen, hydrogen, and water vapor, dissolved oxygen and hydrogen concentrations, electrolyte concentration, and the solid- and solution-phase potential drops. By developing a complete model of the alkaline fuel cell, the interaction of the various transport and kinetic resistances can …