Physical Sciences and Mathematics Commons^™

Shoreline Change Modeling As A Tool In Coastal Environmental Management, Jorge Espinoza Amaguana

Civil & Environmental Engineering Theses & Dissertations

The one-line numerical model GENESIS has been calibrated to evaluate its performance as a tool in providing insights into the physical components to manage the coastal environment. To calibrate the model, physical environmental data, literature research, and computer modeling methodologies were utilized in addressing the objectives of this thesis. The model was applied at three beaches of the Virginia Beach City with different man-made structures by using the actual field wave data for wave year J 997. Waves are the main environmental component affecting the coastal system; however, additional environmental data and the best engineering decision were used as model …

Analyzing The Effects Of Display Characteristics And Cognitive Variables On Performance Using Keystroke And Eye Movement Data, Orhan E. Beckman

Psychology Theses & Dissertations

Information about how operators use their eyes while interacting with visual displays is often an overlooked aspect of human-computer interaction. Such information is fundamental to assessing the quality of software interfaces and understanding the cognitive processes that underlie operator behavior. Other research evaluating information displays evolved from using reaction time and subjective data as dependent variables to using oculometric measures. In the current research conventional performance measures are coupled with oculometric measures to evaluate the influence display characteristics and cognitive variables have on performance.

Twelve subjects used a software program to complete a series of specified tasks. Subjects were asked …

Measurement Of The Photorefractive Grating Phase Shift In A Polymer By An Ac Phase-Modulation Technique, Martin M Liphardt, Stephen Ducharme

Stephen Ducharme Publications

The complex coupling constant of a photorefractive polymer was measured as a function of an applied electric field by use of a modified ac phase modulation technique. We determined that both a photorefractive index grating and a nonphotorefractive absorption grating were present. The electric field dependencies of the amplitude and the phase of the photorefractive gain coefficient were accurately described by standard photorefractive theory. The accuracy of the photorefractive phase shift as measured by this phase-modulation technique was ±1° near phase shifts of 90° and ±3° near phase shifts of 45°.

Iron And Nickel Surface And Interface Anisotropies, Ralph Skomski, D. Sander, C. Schmidthals, Axel Enders, J. Kirschner

Ralph Skomski Publications

The anisotropy of fcc (111) Fe/Ni and Fe/Ni/Fe layers is investigated. The films exhibit an oscillating behavior of the preferential magnetization direction depending on whether the surface layer is Ni or Fe. Anisotropy fields are obtained from polar and perpendicular Kerr hysteresis loops and yield a comparatively small perpendicular Fe/Ni interface anisotropy of about 0.15 mJ/m2. The real-space origin of the interface anisotropy is the interlayer hybridization of the yz, zx, and z² orbitals.

กิจกรรมสิ่งแวดล้อม

Thai Environment

No abstract provided.

การพัฒนาพื้นที่ชายฝั่งทะเลภาคใต้ กับ แผนการจัดการสิ่งแวดล้อม, พรชัย สุตันไชยนนท์

Thai Environment

No abstract provided.

Review Of The United States And Arms Control: The Challenge Of Leadership By Allan S. Krass, David W. Hafemeister

Physics

No abstract provided.

Proton Nmr Spectroscopy As A Probe Of Dinuclear Copper(Ii) Active Sites In Metalloproteins. Characterization Of The Hyperactive Copper(Ii)-Substituted Aminopeptidase From Aeromonas Proteolytica, Richard C. Holz, Brian Bennett, Guanjing Chen, Li-June Ming

Physics Faculty Research and Publications

Proton NMR spectra of the hyperactive Cu(II)-substituted aminopeptidase from Aeromonas proteolytica (AAP) were recorded in both H₂O and D₂O buffered solution at pH 6.7. Several remarkably sharp, well resolved hyperfine shifted ¹H NMR signals were observed in the 70 to −20 ppm chemical shift range. That hyperfine shifted signals were observed is due to spin-coupling of the two Cu(II) ions. Comparison of the spectra recorded in H₂O and D₂O buffered solutions indicated that the signals at 44.6, 43.3, and 17.7 ppm were solvent exchangeable. The two most strongly downfield shifted signals …

Circulation, Vol. 5, No. 4, Center For Coastal Physical Oceanography, Old Dominion University

CCPO Circulation

Summer 1998 issue of CCPO Circulation featuring article "Bay Mouth Climatology"

Digital Image Retrieval Using Shape-Based Queries, James Carswell

Conference papers

In this paper we present the development of a spatial data management system utilizing sketch-based queries for the content-based retrieval of digital images from topographic databases. We discuss our overall strategy and associated algorithmic and implementational aspects, and present the associated database design issues. The query tools devised in this research are employing user-provided sketches of the shape and spatial configuration of the object(s) which should appear in the images to be retrieved. Our strategy is scale-independent. It is inspired by least-squares matching (lsm), and represents an extension of lsm to function with a variety of raster representations. The results …

Next-To-Leading Order Qcd Corrections For The B⁰B⁰ Mixing With An Extended Higgs Sector, Jorg Org Urban, Frank Krauss, Ulrich D. Jentschura, Gerhard Soff

Physics Faculty Research & Creative Works

We present a calculation of the B⁰B⁰ mixing including next-to-leading order (NLO) QCD corrections within the Two-Higgs Doublet Model (2HDM). The QCD corrections at NLO are contained in the factor denoted by η₂ which modifies the result obtained at the lowest order of perturbation theory. In the Standard Model case, we confirm the results for η₂ obtained by Buras, Jamin and Weisz [Nucl. Phys, B 347 (1990) 491]. The factor η₂ is gauge and renormalization prescription invariant and it does not depend on the infrared behaviour of the theory, which constitutes an important test …

Nonlinear Field Dependence Of The Mobility Of A Charge Subjected To A Superposition Of Dichotomous Stochastic Potentials, A. M. Kenkre, Marek Kus, David H. Dunlap, Paul Ernest Parris

Physics Faculty Research & Creative Works

A general prescription is presented to address a large variety of forms of the nonlinear dependence of the static charge mobility on the applied electric field. The system consists of a classical charge subjected to an arbitrarily strong steady state electric field and to a stochastic potential consisting of a linear superposition of an unlimited number of dichotomous potentials in one-dimensional space. It is shown that the nonlinear mobility can be calculated for arbitrary forms of the density function of the individual dichotomous components of the stochastic potential. Specific cases of physical interest are analyzed. One of them provides a …

Reactions Of Oxygen And Nitric Oxide In A Microhollow Electrode Discharge, Joseph L. Desormeaux Jr.

Electrical & Computer Engineering Theses & Dissertations

Microhollow electrode discharges have been developed and researched in the Physical Electronics Research Institute Laboratories. This discharge typically operates in direct current mode. Microhollow electrode discharges are non-thermal discharges that produce electrons with energies greater than 10 electron volts. Passing gas mixtures through non-equilibrium discharges invokes excitation or dissociation of gas molecules.

The scope of my research was to study the effect of the discharge on the chemistry of two gases, oxygen and nitric oxide in nitrogen mixture. Initial experiments were performed in an effort to produce ozone near atmospheric pressure. This seemed possible since the discharge has a high-energy …

Coupled Electrodynamic-Monte Carlo Simulations Of Nanoscale Gaas Terahertz Optical Mixers, Jiang Li

Electrical & Computer Engineering Theses & Dissertations

The concept of mixing or heterodyning has traditionally been used for microwaves and for radio frequency communications. However, the concept can easily be extended into the optical frequency regime. By doing so, the photomixing process can serve as a very versatile tool for both the generation of ultrahigh frequency (terahertz) and the detection of weak optical signals.

The aim of this thesis is to perform a theoretical study of the photomixing process inside GaAs devices as the non-linear elements. A coupled approach which combines the Monte Carlo simulation scheme for the carrier transport, with Maxwell's equation for the electrodynamics, has …

Chemical Synthesis Of Nanostructured Cobalt At Elevated Temperatures, Diandra Leslie-Pelecky, M. Bonder, T. Martin, E.M. Kirkpatrick, X.Q. Zhang, S.-H. Kim, Reuben D. Reike

Diandra Leslie-Pelecky Publications

Chemical synthesis is a versatile technique for fabricating novel nanostructured materials. In the Rieke process, a metal salt is reduced by an alkali in a hydrocarbon solvent to form small, highly reactive particles. Synthesis at an elevated temperature (200°C) increases the as-synthesized particle size and produces higher coercivities and remanence ratios than observed in similar syntheses at room temperature. The ratio of synthesis temperature to solvent boiling point appears to be an important parameter in both coercivity and oxidation resistance.

Elementary Excitation Spectrum Of A Trapped Weakly Interacting Bose-Einstein Condensate, Mircea Marinescu, Anthony F. Starace

Anthony F. Starace Publications

An analytic expression is presented for the elementary excitation spectrum of the Bose-Einstein condensate of a trapped boson system in the weakly interacting, low-density limit. Explicit analytic formulas for the elementary excitation spectrum are obtained for harmonic-oscillator traps. These formulas provide information about the behavior of the elementary excitation levels as a function of the number of atoms and their interaction strength for a given trap geometry. They also provide a low-density benchmark for results of fully numerical calculations.

Thermal Stability And Nanostructure Of Cocrpt Longitudinal Recording Media, Mingjun Yu, Mary F. Doerner, David J. Sellmyer

David Sellmyer Publications

We report a systematic study of activation volumes and their correlation with physical grain sizes and thermal stability in CoCrPt media fabricated by magnetron sputtering. Different underlayers and CoCrPt layer thicknesses were used to provide a range of lateral grain sizes, M_Iδ (product of remanence M_I and film thickness δ) values, and remanence coercivities. Two methods, namely the field-sweep-rate dependence of coercivity and measurements of magnetic viscosity and irreversible susceptibility, were used to determine the activation volumes and the results obtained from the two methods are in reasonable agreement. For CoCrPt layer thickness from 10 nm to …

Folding Under Inequilibrium Conditions As A Possible Reason For Partial Irreversibility Of Heat-Denatured Proteins: Computer Simulation Study, Sergey A. Potekhin, Evgenii L. Kovrigin

Chemistry Faculty Research and Publications

Using computer simulations we have studied possible effects of heating and cooling at different scan rates on unfolding and refolding of macromolecules. We have shown that even the simplest two-state reversible transition can behave irreversibly when an unfavorable combination of cooling rate, relaxation time and activation energy of refolding occurs. On the basis of this finding we suppose that apparent irreversibility of some proteins denatured by heat may result from slow relaxation on cooling rather than thermodynamic instability and/or irreversible alterations of the polypeptide chain. Using this kinetic reversible two-state model, we estimated the effects of the scan rate and …

Structure And Lattice Dynamics Of Dipolarly Disordered 2,3-Dimethylanthracene Crystals, M. Dörr, H. Gerlach, J. Kalus, N. Karl, M. Monkenbusch, I. Natkaniec, U. Schmelzer, W. Schmidt, John J. Stezowski, P. Vorderwisch, M. Warth

John J. Stezowski Publications

2,3-dimethylanthracene (2,3-DMA, C₁₆H₁₄) crystallizes in a pseudocentrosymmetric triclinic lattice with two molecules per unit cell showing dipolar structural disorder of the acentric molecules. Using powder samples the amplitude weighted phonon density of states was measured by inelastic incoherent neutron scattering for different degrees of deuteration. The differences in the resulting spectra can be explained by changes of the dynamics of the molecular bodies or the methyl side groups. By the method of inelastic coherent neutron scattering phonon dispersion curves were determined. The phonon lines are broad even at low temperatures; this fact is supposed to be …

An Injection Modelocked Titanium-Sapphire Laser, James C. Hovater

Electrical & Computer Engineering Theses & Dissertations

I have investigated the possibility of using an injection modelocked Ti-sapphire laser as a illumination source for GaAs photocathodes. A commercial Ti-sapphire laser was modified to accept a seed pulse from a gain-switched diode laser. Modelocked operation was obtained through gain modulation within the Ti-sapphire crystal as a result of injection seeding with a modelocked pulse train from a gain-switched diode laser. The Ti-sapphire laser essentially becomes a pulse amplifier for the diode laser. Unlike conventional modelocked lasers, the pulse repetition rate of this laser can be discretely varied by setting the seed laser repetition rate equal to multiples of …

Determination Of The N-Terminal Amino Acid Residues On Polypeptides In Secondary Wastewaters, Edward L. Creecy

Chemistry & Biochemistry Theses & Dissertations

The N-terminal amino acid residues on polypeptides and proteins were determined in wastewaters prior to chlorination. The terminal amino groups'ere first derivatized with the well known derivatizing agent dansyl chloride, and then the resulting dansyl amino acid hydrolyzed from the peptide chain by a propionic acid/ hydrochloric acid mixture. The resulting dansyl amino acids were then separated and detected using reversed phase high performance liquid chromatography with fluorescence detection. The majority of N-terminal residues detected were the more polar amino acids. Concentrations ranged from 1 x 10^-10 to 3 x 10^-7 moles/liter. It is suggested that the shorter …

The Cluster Multipole Algorithm For Far-Field Computations, Rakesh R. Patel

Electrical & Computer Engineering Theses & Dissertations

Computer simulations of N-body systems are beneficial to study the overall behavior of a number of physical systems in fields such as astrophysics, molecular dynamics, and computational fluid dynamics. A new approach for computer simulations of N-body systems is proposed in this research. The new algorithm is called the Cluster Multipole Algorithm (CMA). The goals of the new algorithm are to improve the applicability to non-point sources and to provide more control on the accuracy over current algorithms. The algorithm is targeted to applications that do not require rebuilding the data structure about the system every time step due to …

Vortex Wake And Exhaust Plume Interaction, Including Ground Effect, Ihab Gaber Adam

Mechanical & Aerospace Engineering Theses & Dissertations

Computational modeling and studies of the near-field wake-vortex turbulent flows, far-field turbulent wake-vortex/exhaust-plume interaction for subsonic and High Speed Civil Transport (HSCT) airplane, and wake-vortex/exhaust-plume interaction with the ground are carried out. The three-dimensional, compressible Reynolds-Averaged Navier-Stokes (RANS) equations are solved using the implicit, upwind, Roe-flux-differencing, finite-volume scheme. The turbulence models of Baldwin and Lomax, one-equation model of Spalart and Allmaras and two-equation shear stress transport model of Menter are implemented with the RANS solver for turbulent-flow modeling.

For the near-field study, computations are carried out on a fine grid for a rectangular wing with a NACA-0012 airfoil section and …

High Pressure Radio-Frequency Microhollow Cathode Discharges, Anja Annett Muller

Electrical & Computer Engineering Theses & Dissertations

A new field of microhollow cathode discharges is represented by the RF microhollow cathode discharge. So far, the behavior and related physical processes of the RF microhollow cathode discharge are not well investigated.

RF microhollow discharges in air at high pressures were investigated under different experimental conditions. The geometry was changed by reducing the cathode hole diameter and the dielectric spacer thickness. By adding a noble gas to air, the influence of additive gases was explored. Additionally, the parallel operation of RF microhollow discharges was investigated.

It was shown that stable RF microhollow cathode discharges could only be sustained up …

Optimization Of Variable Area Transect Sampling Using Monte Carlo Simulation, Richard M. Engeman, Robert T. Sugihara

United States Department of Agriculture Wildlife Services: Staff Publications

An extensive simulation study was conducted to optimize the number, r, of population members to be encountered from each random starting point in variable area transect (VAT) sampling. The quality of estimation provided by the original calculation formula presented by K. R. Parker in 1979 was compared to another formula that was a Morisita analog intended to reduce bias when sampling aggregated populations. Monte Carlo simulations covered 64 combinations of four spatial patterns, four sample sizes, and four densities. Values of r from 3 through 10 were considered in each case. Relative root mean squared error was used as …

Results Of Investigations Into The Groundwater Response And Productivity Of High Water Use Agricultural Systems 1990-1997. 2. Souths' Catchment (Darkan), A D. Smith, Richard J. George Dr, P R. Scott, D L. Bennett, R J. Rippon, G J. Orr

Resource management technical reports

High water use vegetation systems for salinity control were trialed on a 90 ha catchment located 12 km north north-west of Darkan, Western Australia. The catchment receives about 560 mm annual rainfall and 1895 mm annual evaporation. The catchment is characterised by a number of actively expanding seeps which are developing under the strong geological control of quartz and dolerite dykes. Development of salinity is also influenced by high recharge rates in the free draining gravel soils of the upper slope.

Results Of Investigations Into The Groundwater Response And Productivity Of High Water Use Agricultural Systems 1990-1997 1. Wooldridge/Wright's Catchment (Kojonup), A D. Smith, Richard J. George Dr, P R. Scott, D L. Bennett, R J. Rippon, G J. Orr

Resource management technical reports

High water use vegetation systems for salinity control were trialed on a 170 ha catchment located 13 km north of Kojonup, Western Australia. The catchment receives about 470 mm annual rainfall and 1825 mm annual evaporation.

Managing Granite Outcrops. Revegetation On Farms Information Kit, David Bicknell, Department Of Conservation And Land Management (Calm), The Royal Society Of Western Australia

Natural resources published reports

In Western Australia, granite outcrops rise from the surrounding countryside like an extensive island chain, stretching from the high rainfall south-west to the arid interior. They are extremely rich in biodiversity, which can change dramatically from outcrop to outcrop. They may contain relics of unique plant and animal populations and are very significant for nature conservation.

Granite outcrops can also be a major source of groundwater recharge within catchments, especially where the surrounding fringe and woodland vegetation has been cleared.

What is granite?

*Granite is an igneous rock consisting of large crystals of quartz, feldspar and mica or hornblende.

* …

Development And Evaluation Of A New Soil Erosion- Productivity Index Model (Sepim), Metthew Mulengera

Tanzania Journal of Engineering and Technology (TJET)

A soil erosion-productivity model which considers rhe effect of soil water storage Capacity. crop evapotranspiration, soil chemical and physical properties inrporrantfor Crop growth has been developed. The model is shown to give good predictions and it promises to be an improvement over the former productivity Index (PI). It also promises to give more reliable results than the currently used /nodels which consider only soil water storage capacity and crop e ' 'apotransp iration.

State Of The Fisheries Report 1997/1998, Jim W. Penn

Status Reports of the Fisheries and Aquatic Resources

The State of the Fisheries document is designed as an essential supplement to the Annual Report to Parliament. By summarising data such as landings, effort, catch rates, stock assessment and breeding stock levels, this document provides a valuable reference point for all Western Australian fisheries of major importance to the commercial, recreational and aquaculture sectors. Information relevant to Fisheries WA's Fish and Fish Habitat Protection Program is also provided. The report indicates that overall the major fish stocks which support fisheries in Western Australia continue to be in a reasonably healthy condition. Those species which are being harvested at levels …