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1998

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Articles 571 - 600 of 2574

Full-Text Articles in Physical Sciences and Mathematics

Review Of Visual Complex Analysis, By Tristan Needham, Frank A. Farris Jul 1998

Review Of Visual Complex Analysis, By Tristan Needham, Frank A. Farris

Mathematics and Computer Science

Tristan Needham's Visual Complex Analysis will show you the field of complex analysis in a way you almost certainly have not seen before. Drawing on historical sources and adding his own insights, Needham develops the subject from the ground up, drawing attractive pictures at every step of the way. If you have time for a year course, full of fascinating detours, this is the perfect text; by picking and choosing, you could use it for a variety of shorter courses. I am tempted to hide the book from my own students, in order to appear the more clever for popping …


Evolution Of Mixed-State Regions In Type-Ii Superconductors, Chaocheng Huang, Tom Svobodny Jul 1998

Evolution Of Mixed-State Regions In Type-Ii Superconductors, Chaocheng Huang, Tom Svobodny

Mathematics and Statistics Faculty Publications

A mean-field model for dynamics of superconducting vortices is studied. The model, consisting of an elliptic equation coupled with a hyperbolic equation with discontinuous initial data, is formulated as a system of nonlocal integrodifferential equations. We show that there exists a unique classical solution in C1+α0) for all t > Ω, where Ω0 is the initial vortex region that is assumed to be in C1+α. Consequently, for any time t, the vortex region Ωt is of C1+α, and the vorticity is in Cαt).


Minimizing The Diameter In Tree Networks Under Edge Reductions, Susanne E. Hambrusch, Hyeong-Seok Lim Jul 1998

Minimizing The Diameter In Tree Networks Under Edge Reductions, Susanne E. Hambrusch, Hyeong-Seok Lim

Department of Computer Science Technical Reports

No abstract provided.


Seasonal Variation In Reception Of Fin Whale Calls At Five Geographic Areas In The North Pacific Jul 1998

Seasonal Variation In Reception Of Fin Whale Calls At Five Geographic Areas In The North Pacific

United States Department of Commerce: Staff Publications

In late August 1991 scientists at the National Oceanic and Atmospheric Administration’s (NOAA) National Marine Mammal Laboratory (NMML) and Pacific Marine Environmental Laboratory (PMEL) began a pilot study to investigate the capability of hydrophones from the US. Navy’s fixed array system to detect large whales in the North Pacific by passive reception of their calls. PMEL had previously established a direct data link from five bottom-mounted arrays of the Navy SOSUS (Sound Surveillance System), via the Naval Oceanographic Processing Facility (NOPF) at Whidbey Island, Washington, to study low-level seafloor seismicity (Fox et al. 1994). PMEL subsequently provided NMML tapes of …


Iron And Nickel Surface And Interface Anisotropies, Ralph Skomski, D. Sander, C. Schmidthals, Axel Enders, J. Kirschner Jul 1998

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.


Magnetoelectric Néel Anisotropies, Ralph Skomski Jul 1998

Magnetoelectric Néel Anisotropies, Ralph Skomski

Ralph Skomski Publications

The applicability of Néel's pair model to metallic 3d surfaces and interfaces is explained in terms of the tight-binding moments theorem. The Néel model reproduces itinerant magnetism so long as the band structure is approximated by third-moment atomic-pair contributions. This establishes an atomic Néel description of interfaces and impurities. The Néel parameter g depends on the d-band filling and, to some extent, on the atomic structure.


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 Jul 1998

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.


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 Jul 1998

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 …


Experimental Observation Of Correlated Magnetic Reconnection And Alfvénic Ion Jets, Thomas W. Kornack , '98, Peter K. Sollins , '98, Michael R. Brown Jul 1998

Experimental Observation Of Correlated Magnetic Reconnection And Alfvénic Ion Jets, Thomas W. Kornack , '98, Peter K. Sollins , '98, Michael R. Brown

Physics & Astronomy Faculty Works

Correlations between magnetic reconnection and energetic ion flow events have been measured with merging force free spheromaks at the Swarthmore Spheromak Experiment. The reconnection layer is measured with a linear probe array and ion flow is directly measured with a retarding grid energy analyzer. Flow has been measured both in the plane of the reconnection layer and out of the plane. The most energetic events occur in the reconnection plane immediately after formation as the spheromaks dynamically merge. The outflow velocity is nearly Alfvenic. As the spheromaks form equilibria and decay, the flow is substantially reduced.


Adopting An Ecosystem Approach: Local Variability In Remedial Action Planning, Wendy A. Kellogg Jul 1998

Adopting An Ecosystem Approach: Local Variability In Remedial Action Planning, Wendy A. Kellogg

All Maxine Goodman Levin School of Urban Affairs Publications

Provides information on a study that describes the adoption of an ecosystem approach by lead agencies in two remedial action plans (RAP) for Great Lakes basin. Guidelines on what an ecosystem approach is; Account on International Joint Commission (IJC); Congruency between RAP processes with IJC articulation; How variability in local conditions shaped the innovation adoption process.


Comparison Of Observed And Simulated Grow-Finish Swine Performance Under Summer Conditions, Larry W. Turner, Thomas C. Bridges, Richard D. Coffey, Richard S. Gates, Gary R. Parker, Tami M. Brown-Brandl, Douglas G. Overhults Jul 1998

Comparison Of Observed And Simulated Grow-Finish Swine Performance Under Summer Conditions, Larry W. Turner, Thomas C. Bridges, Richard D. Coffey, Richard S. Gates, Gary R. Parker, Tami M. Brown-Brandl, Douglas G. Overhults

Biosystems and Agricultural Engineering Faculty Publications

As a part of a National Pork Producers Council educational program, our research and extension team at the University of Kentucky was linked with an independent commercial swine producer to test the NCPIG model against observed commercial on-farm data. This experience provided improved information for model development as well as increased producer insight into the data input needs and potential benefits of modeling. Detailed production information comparisons between the NCPIG model and producer data are presented for summer time conditions to assess the validity of the NCPIG model for simulation of grow-finish swine performance. Results demonstrated that the NCPIG model …


Recovery Plan For The Blue Whale (Balaenoptera Musculus), Randall R. Reeves, Phillip J. Clapham, Robert L. Brownell Jr., Gregory K. Silber Jul 1998

Recovery Plan For The Blue Whale (Balaenoptera Musculus), Randall R. Reeves, Phillip J. Clapham, Robert L. Brownell Jr., Gregory K. Silber

United States Department of Commerce: Staff Publications

Recovery plans identify reasonable actions which are believed to be required to recover and/or protect endangered species. Plans are prepared by the National Marine Fisheries Service (NMFS) and the U.S. Fish and Wildlife Service (FWS) and sometimes with the assistance of recovery teams, contractors, State agencies, and others. This plan was prepared by Randall R. Reeves, Phillip J. Clapham, Robert L. Brownell, Jr., and Gregory K. Silber for NMFS. Recovery plans do not necessarily represent the views nor the official positions or approvals of any individuals or agencies, other than those of NMFS, and they represent the views of NMFS …


Gray Wolf (Canis Lupus) Jul 1998

Gray Wolf (Canis Lupus)

Rocky Mountain Wolf Recovery: Annual Reports

Historically, most Native Americans revered gray wolves, trying to emulate their cunning and hunting abilities. However, wolves became nearly extinct in the lower 48 states in the early part of the 20th century because settlers believed wolves caused widespread livestock losses. Constantly persecuted and targeted by large scale predator eradication programs sponsored by the federal government, wolves have been pursued with more passion and determination than any other animal in U.S. history. By the time wolves were finally protected by the Endangered Species Act of 1973, they had been exterminated from the lower 48 states, except for a few hundred …


Canadian Cooperative Wildlife Health Centre, Volume 5, Summer 1998 Jul 1998

Canadian Cooperative Wildlife Health Centre, Volume 5, Summer 1998

Canadian Cooperative Wildlife Health Centre: Newsletters and Publications

CCWHC Involvement with Botulism
The Value of A Complete Necropsy in Controversial Situations
Yersiniosis in Snowshoe Hares - Newfoundland
Mass mortality of young harp seals
Salmonellosis in passerine birds
Canine Parvovirus Type 2 Infection in a Wild Wolf
Presumptive Atoxoplasmosis in Common Grackles
Evidence of Leptospira infection in raccoons from Middlesex and Kent counties, Ontario
Toxicity Events


Single Crystal Raman Spectra Of 1,2,4,5-Tetrabromobenzene: Calculational And Experimental Assignment Of The Internal Modes, K.M. White, Craig J. Eckhardt Jul 1998

Single Crystal Raman Spectra Of 1,2,4,5-Tetrabromobenzene: Calculational And Experimental Assignment Of The Internal Modes, K.M. White, Craig J. Eckhardt

Craig J. Eckhardt Publications

A detailed study of the fundamental internal modes of the 1,2,4,5-tetrabromobenzene crystal has provided assignments of Raman-active modes consistent with polarized single-crystal measurements. A normal-mode calculation based on a valence force field derived from brominated and chlorinated benzenes is found to be in excellent agreement with the assignments. Additional bands arising from anharmonic interactions of the fundamentals are also assigned.


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 Jul 1998

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 …


Digital Image Retrieval Using Shape-Based Queries, James Carswell Jul 1998

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 …


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 Jul 1998

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 …


Perturbation Results For Projecting A Point Onto A Linear Manifold, Jiu Ding Jul 1998

Perturbation Results For Projecting A Point Onto A Linear Manifold, Jiu Ding

Faculty Publications

Some new results will be presented on the perturbation analysis for the orthogonal projection of a point onto a linear manifold. The obtained perturbation upper bound is with respect to the distance from the perturbed solution to the unperturbed manifold.


Graft Copolymerization Of Methacrylic Acid, Acrylic Acid And Methyl Acrylate Onto Styrene–Butadiene Block Copolymer, David D. Jiang, Charles Wilkie Jul 1998

Graft Copolymerization Of Methacrylic Acid, Acrylic Acid And Methyl Acrylate Onto Styrene–Butadiene Block Copolymer, David D. Jiang, Charles Wilkie

Chemistry Faculty Research and Publications

Methyl acrylate, methacrylic acid, and acrylic acid have been graft copolymerized onto styrene–butadiene block copolymer. All three monomers react through the macroradical interacting with the double bond of butadiene. The site of reaction has been established by infrared spectroscopy. For methyl acrylate every unit of the styrene–butadiene block copolymer is grafted but only a small fraction is grafted when the acids are used. The difference apparently lies in the fact that the reaction with the ester is homogeneous while with the acids the reactions are heterogeneous.


A Molecular Mechanics Simulation Of Cracks And Fractures In A Sheet Of Ice, Donald Greenspan Jul 1998

A Molecular Mechanics Simulation Of Cracks And Fractures In A Sheet Of Ice, Donald Greenspan

Mathematics Technical Papers

Rectangular, two dimensional sheets of ice molecules are both stressed and compressed. Computer examples compare dynamical responses when the plate has a slot or does not have a slot. The mechanisms for both crack and fracture development are clearly delineated on the molecular level.


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 Jul 1998

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.


Low Energy Electron Gun Power Control Unit, Chad Fish, Jr Dennison Jul 1998

Low Energy Electron Gun Power Control Unit, Chad Fish, Jr Dennison

Senior Theses and Projects

Near-Earth orbiting spacecraft are subject to a variety of physical environmental elements. Of these, natural space plasma and solar radiation produce spacecraft charging. Spacecraft charging consists of surface (external) and deep (internal) dielectric charging.

Natural space plasma is composed of electrons and positively charged atoms called ions. The plasma is generated by energy from solar radiation and high energy particles emitted by geomagnetic storms. The electrons produce a negative current and the ions produce a positive current. Positive photoelectron currents produced by solar radiation of spacecraft surfaces also add to the electrical fluxesi.

As spacecraft move through the …


Optimization Of Variable Area Transect Sampling Using Monte Carlo Simulation, Richard M. Engeman, Robert T. Sugihara Jul 1998

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 …


Isospectral Sets For Fourth-Order Ordinary Differential Operators, Lester Caudill, Peter A. Perry, Albert W. Schueller Jul 1998

Isospectral Sets For Fourth-Order Ordinary Differential Operators, Lester Caudill, Peter A. Perry, Albert W. Schueller

Department of Math & Statistics Faculty Publications

Let L(p)u = D4u - (p1u)+ p2u be a fourth-order differential operator acting on L2[0; 1] with p (p1; p2) belonging to L2[0, 1] x L2[0, 1] and boundary conditions u(0) = u''(0) = u(1) = u''(1) = 0. We study the isospectral set of L(p) when L(p) has simple spectrum. In particular we show that for such p …


Fuzzy Logic Applied To System Control To Enhance Commercial Appliance Performance, Glenn Moffett Jul 1998

Fuzzy Logic Applied To System Control To Enhance Commercial Appliance Performance, Glenn Moffett

Doctoral Dissertations

The purpose of this research is to determine the usefulness of fuzzy logic and fuzzy control when applied to a commercial appliance. Fuzzy logic is a structured, model-free estimator that approximates a function through linguistic input/output associations. Fuzzy rule-based systems apply these methods to solve many types of "real-world" problems, especially where a system is difficult to model, is controlled by a human operator or expert, or where ambiguity or vagueness is common.

This dissertation presents fuzzy sets, fuzzy systems, and fuzzy control, with an example conveying the use of fuzzy control of a consumer product and an overview of …


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 Jul 1998

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 …


Center For Sustainable Agricultural Systems Newsletter, July/August 1998 Jul 1998

Center For Sustainable Agricultural Systems Newsletter, July/August 1998

Center for Sustainable Agricultural Systems: Newsletters (1993-2000)

Contents:

Centers Propose Education on Conservation Buffers: The Rural/Urban Interface

Highlights of Upcoming Book: Under The Blade (Part 2)

Using Ecological Footprints to Define Sustainability

Integrated Farm Update: Accumulation of Residual Nitrate Beneath Corral Areas

CSAS Fall Seminar Series Schedule: Small Farming Systems for the Midwest

NOVA University: Regional Education Focus


Probing Electronic Radial Wave Packets Using Impulsive Momentum Retrieval, M. B. Campbell, Thomas J. Bensky, Robert R. Jones Jul 1998

Probing Electronic Radial Wave Packets Using Impulsive Momentum Retrieval, M. B. Campbell, Thomas J. Bensky, Robert R. Jones

Physics

Subpicosecond half-cycle pulses and a single-shot imaging detector have been used to monitor the evolution of electronic radial wave packets in calcium. The time-dependent momentum-space probability distribution is obtained using the impulsive momentum retrieval (IMR) method. The measured distributions are compared to the results of quantum and classical simulations allowing a comprehensive evaluation of the benefits and limitations of the IMR method.


กิจกรรมสิ่งแวดล้อม Jul 1998

กิจกรรมสิ่งแวดล้อม

Thai Environment

No abstract provided.