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2006

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Articles 3751 - 3780 of 3784

Full-Text Articles in Physical Sciences and Mathematics

Biconformal Matter Actions, A. Wehner, James Thomas Wheeler Jan 2006

Biconformal Matter Actions, A. Wehner, James Thomas Wheeler

All Physics Faculty Publications

We extend 2n-dim biconformal gauge theory by including Lorentz-scalar matter fields of arbitrary conformal weight. We show that for a massless scalar field of conformal weight zero in a torsion-free biconformal geometry, the solution is determined by the Einstein equation on an n-dim submanifold, with the stress-energy tensor of the scalar field as source. The matter field satisfies the n-dim Klein-Gordon equation.


Coalgebras And Their Logics, Alexander Kurz Jan 2006

Coalgebras And Their Logics, Alexander Kurz

Engineering Faculty Articles and Research

"Transition systems pervade much of computer science. This article outlines the beginnings of a general theory of specification languages for transition systems. More specifically, transition systems are generalised to coalgebras. Specification languages together with their proof systems, in the following called (logical or modal) calculi, are presented by the associated classes of algebras (e.g., classical propositional logic by Boolean algebras). Stone duality will be used to relate the logics and their coalgebraic semantics."


The Lazarus Project. Ii. Spacelike Extraction With The Quasi-Kinnersley Tetrad, Manuela Campanelli, Bernard Kelly, Carlos O. Lousto Jan 2006

The Lazarus Project. Ii. Spacelike Extraction With The Quasi-Kinnersley Tetrad, Manuela Campanelli, Bernard Kelly, Carlos O. Lousto

Physics and Astronomy Faculty Publications and Presentations

The Lazarus project was designed to make the most of limited 3D binary black-hole simulations, through the identification of perturbations at late times, and subsequent evolution of the Weyl scalar Ψ4 via the Teukolsky formulation. Here we report on new developments, employing the concept of the “quasi-Kinnersley” (transverse) frame, valid in the full nonlinear regime, to analyze late-time numerical space-times that should differ only slightly from Kerr. This allows us to extract the essential information about the background Kerr solution, and through this, to identify the radiation present. We explicitly test this procedure with full-numerical evolutions of Bowen-York data for …


Relativistic Three-Body Effects In Black Hole Coalescence, Manuela Campanelli, Miranda Dettwyler, Mark Hannam, Carlos O. Lousto Jan 2006

Relativistic Three-Body Effects In Black Hole Coalescence, Manuela Campanelli, Miranda Dettwyler, Mark Hannam, Carlos O. Lousto

Physics and Astronomy Faculty Publications and Presentations

Three-body interactions are expected to be common in globular clusters and in galactic cores hosting supermassive black holes. We consider an equal-mass binary black hole system in the presence of a third black hole. Using numerically generated binary black hole initial data sets, and first and second-order post-Newtonian (1PN and 2PN) techniques, we find that the presence of the third black hole has nonnegligible relativistic effects on the location of the binary’s innermost stable circular orbit (ISCO), and that these effects arise at 2PN order. For a stellar-mass black hole binary in orbit about a supermassive black hole, the massive …


Search For Gravitational Waves From Binary Black Hole Inspirals In Ligo Data, B. P. Abbott, R. Abbott, W. G. Anderson, Mario C. Diaz, Wm. R. Johnston, Soumya Mohanty, Soma Mukherjee, Cristina V. Torres Jan 2006

Search For Gravitational Waves From Binary Black Hole Inspirals In Ligo Data, B. P. Abbott, R. Abbott, W. G. Anderson, Mario C. Diaz, Wm. R. Johnston, Soumya Mohanty, Soma Mukherjee, Cristina V. Torres

Physics and Astronomy Faculty Publications and Presentations

We report on a search for gravitational waves from binary black hole inspirals in the data from the second science run of the LIGO interferometers. The search focused on binary systems with component masses between 3 and 20M⊙. Optimally oriented binaries with distances up to 1 Mpc could be detected with efficiency of at least 90%. We found no events that could be identified as gravitational waves in the 385.6 hours of data that we searched.


Ferromagnetic Resonance Investigations On Ga0.965mn0.035as Film, S. Balascuta, X. Liu, D. V. Baxter, J. Carini, T. Wojtowicz, Y. Sasaki, J. Furdyna, Mircea Chipara Jan 2006

Ferromagnetic Resonance Investigations On Ga0.965mn0.035as Film, S. Balascuta, X. Liu, D. V. Baxter, J. Carini, T. Wojtowicz, Y. Sasaki, J. Furdyna, Mircea Chipara

Physics and Astronomy Faculty Publications and Presentations

Ferromagnetic resonance studies of the temperature dependence of magnetic anisotropies in a Ga0.965Mn0.035As film between 5 and 40K are reported. The in-plane and out-of-the-plane angular dependences of the resonance field were analyzed within the Landau-Lifshitz-Gilbert approach. The second- and fourth-order magnetic anisotropy energies were derived. The temperature dependence of magnetization and of magnetic anisotropy were studied by superconducting quantum interference device and ferromagnetic resonance.


Electrical Pulse Formation During High Temperature Reaction Between Ni And Al, Mona Setoodeh, Karen S. Martirosyan, Dan Luss Jan 2006

Electrical Pulse Formation During High Temperature Reaction Between Ni And Al, Mona Setoodeh, Karen S. Martirosyan, Dan Luss

Physics and Astronomy Faculty Publications and Presentations

An electric voltage pulse (duration of about 2ms) with an amplitude of up to 0.6V was generated during the reaction between nickel and aluminum powders by a high temperature moving reaction front. The electrical signal formed during the initial stages of the combustion was annihilated before the moving front attained its maximum temperature. The voltage amplitude and combustion temperature depended on the particle size of the reactants as well as the Al to Ni ratio in the reactant mixture, and their largest values were attained for a mixture containing 27–31.5wt% Al. The combustion temperature increased when smaller Al particles were …


An Implementation Of The It Fundamentals Knowledge Area In An Introductory It Course, Cheryl L. Aasheim, Choong Kwon Lee, Han Reichgelt Jan 2006

An Implementation Of The It Fundamentals Knowledge Area In An Introductory It Course, Cheryl L. Aasheim, Choong Kwon Lee, Han Reichgelt

Department of Information Technology Faculty Publications

The recently promulgated IT model curriculum contains IT fundamentals (ITF) as one of its knowledge areas. It is intended to give students a broad understanding of (1) the IT profession and the skills that students must develop to become successful IT professionals and (2) the academic discipline of IT and its relationship to other disciplines. The model curriculum recommends 33 lecture hours to complete the IT fundamentals knowledge. The model curriculum also recommends that the material relevant to the IT fundamentals knowledge area be offered early in the curriculum, for example in an Introduction to IT course; however, many institutions …


Book Review: The Amateur Astronomer's Introduction To The Celestial Sphere, T. D. Oswalt Jan 2006

Book Review: The Amateur Astronomer's Introduction To The Celestial Sphere, T. D. Oswalt

Publications

This document is Dr. Oswalt’s review of The Amateur Astronomer's Introduction to the Celestial Sphere by William Millar. Cambridge, 2006 299p, 052167123X $40.00, 9780521671231 $40.00.


Observations Of Triboelectric Charging Effects On Langmuir-Type Probes In Dusty Plasma, Aroh Barjatya, C. M. Swenson Jan 2006

Observations Of Triboelectric Charging Effects On Langmuir-Type Probes In Dusty Plasma, Aroh Barjatya, C. M. Swenson

Publications

Investigation of Earth’s mesosphere using sounding rockets equipped with a myriad of instruments has been a highly active field in the last 2 decades. This paper presents data from three separate instruments: an RF impedance probe, a DC fixed bias Langmuir probe, and an electric field probe, that were flown on a mesospheric sounding rocket flight investigating the presence of charged dust within and/or around a sporadic metal layer. The combined data set indicates a case of payload surface charging, the causes of which are investigated within this paper. A generic circuit model is developed to analyze payload charging and …


The White Dwarf Luminosity Function From Sloan Digital Sky Survey Imaging Data, Hugh C. Harris, Jeffrey A. Munn, Mukremin Kilic, James W. Liebert, Kurtis A. Williams, Ted Von Hippel, Stephen E. Levine, David G. Monet, Daniel J. Eisenstein, S. J. Kleinman, T. S. Metcalfe, Atsuko Nikka, D. E. Winget, J. Brinkmann, Masataka Fukugita, G. R. Knapp, Robert H. Lupton, J. Allyn Smith, Donald P. Schneider Jan 2006

The White Dwarf Luminosity Function From Sloan Digital Sky Survey Imaging Data, Hugh C. Harris, Jeffrey A. Munn, Mukremin Kilic, James W. Liebert, Kurtis A. Williams, Ted Von Hippel, Stephen E. Levine, David G. Monet, Daniel J. Eisenstein, S. J. Kleinman, T. S. Metcalfe, Atsuko Nikka, D. E. Winget, J. Brinkmann, Masataka Fukugita, G. R. Knapp, Robert H. Lupton, J. Allyn Smith, Donald P. Schneider

Publications

A sample of white dwarfs is selected from the Sloan Digital Sky Survey (SDSS) Data Release 3 using their reduced proper motions, based on improved proper motions from combined SDSS and USNO-B data. Numerous SDSS and follow-up spectra (Kilic and coworkers) are used to quantify completeness and contamination of the sample; kinematicsmodels are used to understand and correct for velocity-dependent selection biases.A luminosity function is constructed covering the range 7 < Mbol < 16, and its sensitivity to various assumptions and selection limits is discussed. The white dwarf luminosity function based on 6000 stars is remarkably smooth and rises nearly monotonically to Mbol=15.3. It then drops abruptly, although the small number of low-luminosity stars in the sample and their unknown atmospheric composition prevent quantitative conclusions about this decline. Stars …


Natural Resource Management Issues In The Avon River Basin, Paul Galloway Jan 2006

Natural Resource Management Issues In The Avon River Basin, Paul Galloway

Resource management technical reports

Analyses the risk of soil, land and water degradation within the Avon River Basin of Western Australia. Information is based on the interpretation of the characteristics of soils and landscapes within the Avon River basin. This report deals with 15 natural resource management issues and describes the extent of each issue, the impacts that each issue will have, management options that can be used to deal with each issue, and the effectiveness of each management option in dealing with the issues.


Surface Water Assessment For The Buntine-Marchagee Recovery Catchment, R Short, P Whale, D Farmer, N Coles Jan 2006

Surface Water Assessment For The Buntine-Marchagee Recovery Catchment, R Short, P Whale, D Farmer, N Coles

Resource management technical reports

No abstract provided.


Ravensthorpe Area Catchment Appraisal 2006, A Massenbauer Jan 2006

Ravensthorpe Area Catchment Appraisal 2006, A Massenbauer

Resource management technical reports

The Ravensthorpe area covers 861, 000 hectares. Ninety percent of the study area covered in this report falls within the Ravensthorpe Shire, Western Australia. This document aims to give the reader a starting point from which to further assess larger scale areas of the catchment for the purpose of planning to reverse and improve land degradation and sustainable farming in Western Australia.


Evaluation Of The Sustainable Grazing On Saline Lands - Wa Producer Network : Influence On Practice Change And Decision-Making Capacity, Rebecca Heath, Jamie Bowyer, T M. Lacey Jan 2006

Evaluation Of The Sustainable Grazing On Saline Lands - Wa Producer Network : Influence On Practice Change And Decision-Making Capacity, Rebecca Heath, Jamie Bowyer, T M. Lacey

Resource management technical reports

No abstract provided.


Soil-Landscapes Of Western Australia's Rangelands And Arid Interior, Peter J. Tille Jan 2006

Soil-Landscapes Of Western Australia's Rangelands And Arid Interior, Peter J. Tille

Resource management technical reports

This report documents the process of placing the most recent and detailed mapping of Western Australia's Rangelands and Arid interior that is available into a hierarchy of soil-landscape mapping units. It also provides descriptions of the soil-landscape regions, provinces and zones identified.


Comments On The Mechanism Of Aging Of Antimony Doped Tin Oxide Based Electrochromic Devices, Joo C. Chan, Nicole A. Hannah, Shankar B. Rananavare, Laura Yeager, Liviu Dinescu, Ashok Saraswat, Pradeep Iyer, James P. Coleman Jan 2006

Comments On The Mechanism Of Aging Of Antimony Doped Tin Oxide Based Electrochromic Devices, Joo C. Chan, Nicole A. Hannah, Shankar B. Rananavare, Laura Yeager, Liviu Dinescu, Ashok Saraswat, Pradeep Iyer, James P. Coleman

Chemistry Faculty Publications and Presentations

Electrochromic effects of antimony doped tin oxide (ATO) nanoparticles are investigated to probe device yellowing (degradation). Voltage vs contrast ratio curves exhibit hysteresis, i.e., image-sticking phenomena due to irreversible charge insertion. X-ray, impedance and optical b* studies suggest that the yellowing/charge trapping is nanoparticle size-dependent with 4 nm size particles exhibiting the least yellowing. Yellowing results in increased impedances of electrode–electrolyte interface and electrode corrosion. Plausible sources of discoloration are formation of insulating complex alkali oxide film, carrier inversion (n-to-p type) through electrochemical Li doping, redeposition of the corroded electrode material and perhaps residual concentration of charge-transfer species.


Computer Models For Legal Prediction, Kevin D. Ashley, Stephanie Bruninghaus Jan 2006

Computer Models For Legal Prediction, Kevin D. Ashley, Stephanie Bruninghaus

Articles

Computerized algorithms for predicting the outcomes of legal problems can extract and present information from particular databases of cases to guide the legal analysis of new problems. They can have practical value despite the limitations that make reliance on predictions risky for other real-world purposes such as estimating settlement values. An algorithm's ability to generate reasonable legal arguments also is important. In this article, computerized prediction algorithms are compared not only in terms of accuracy, but also in terms of their ability to explain predictions and to integrate predictions and arguments. Our approach, the Issue-Based Prediction algorithm, is a program …


Ip's Problem Child: Shifting The Paradigms For Software Protection, Jacqueline D. Lipton Jan 2006

Ip's Problem Child: Shifting The Paradigms For Software Protection, Jacqueline D. Lipton

Articles

Computer software is somewhat of a problem child for intellectual property law. Courts and legislatures have struggled to encourage innovations in software development while, at the same time, attempting to avoid undesirable digital information monopolies. Neither the patent nor the copyright system has provided a particularly satisfactory paradigm for software protection. Although patents have received greater attention than copyrights in the software context (consider, for example, the recent BlackBerry case), copyright law arguably creates more insidious undercurrents in today's marketplace. This is partly because we have not yet appreciated the potential impact of recent developments in programming methodology and digital …


Rocket And Radar Investigation Of Background Electrodynamics And Bottom-Type Scattering Layers At The Onset Of Equatorial Spread F, D. L. Hysell, M. F. Larsen, C. M. Swenson, Aroh Barjatya, Et. Al Jan 2006

Rocket And Radar Investigation Of Background Electrodynamics And Bottom-Type Scattering Layers At The Onset Of Equatorial Spread F, D. L. Hysell, M. F. Larsen, C. M. Swenson, Aroh Barjatya, Et. Al

Publications

Sounding rocket experiments were conducted during the NASA EQUIS II campaign on Kwajalein Atoll designed to elucidate the electrodynamics and layer structure of the postsunset equatorial F region ionosphere prior to the onset of equatorial spread F (ESF). Experiments took place on 7 and 15 August 2004, each comprised of the launch of an instrumented and two chemical release sounding rockets. The instrumented rockets measured plasma number density, vector electric fields, and other parameters to an apogee of about 450 km. The chemical release rockets deployed trails of trimethyl aluminum (TMA) which yielded wind profile measurements. The Altair radar was …


On Doubly Periodic Solutions Of Quasilinear Hyperbolic Equations Of The Fourth Order, T. Kiguradze, T. Smith Jan 2006

On Doubly Periodic Solutions Of Quasilinear Hyperbolic Equations Of The Fourth Order, T. Kiguradze, T. Smith

Publications

The problem on doubly periodic solutions is considered for a class of quasilinear hyperbolic equations. Effective sufficient conditions of solvability and unique solvability of this problem are established.


Transfer Of Training From Flight Training Devices To Flight For Ab-Initio Pilots, Nickolas D. Macchiarella, Pamela K. Arban, Shawn M. Doherty Jan 2006

Transfer Of Training From Flight Training Devices To Flight For Ab-Initio Pilots, Nickolas D. Macchiarella, Pamela K. Arban, Shawn M. Doherty

Publications

The application of flight simulation to meet pilot training needs continues to evolve. Flight simulations built with powerful and inexpensive computers are making high fidelity simulation available as a medium for training ab-initio pilots at Pilot Schools and Training Centers. The researchers conducted an 18-month study that applied an experimental flight-training curriculum comprised of 60% flight training device (FTD) flight and 40% airplane flight to certify Private Pilots under Federal Aviation Regulation (FAR) Part 142. The results from the research provided data to ascertain the effective transfer for each flight-training task. Ab-initio student pilots practiced each task to standard in …


Kernels Of Directed Graph Laplacians, John S. Caughman Iv, J. J. P. Veerman Jan 2006

Kernels Of Directed Graph Laplacians, John S. Caughman Iv, J. J. P. Veerman

Mathematics and Statistics Faculty Publications and Presentations

Let G denote a directed graph with adjacency matrix Q and in- degree matrix D. We consider the Kirchhoff matrix L = D − Q, sometimes referred to as the directed Laplacian. A classical result of Kirchhoff asserts that when G is undirected, the multiplicity of the eigenvalue 0 equals the number of connected components of G. This fact has a meaningful generalization to directed graphs, as was observed by Chebotarev and Agaev in 2005. Since this result has many important applications in the sciences, we offer an independent and self-contained proof of their theorem, showing in this paper …


The Convergence Of V-Cycle Multigrid Algorithms For Axisymmetric Laplace And Maxwell Equations, Jay Gopalakrishnan, Joseph E. Pasciak Jan 2006

The Convergence Of V-Cycle Multigrid Algorithms For Axisymmetric Laplace And Maxwell Equations, Jay Gopalakrishnan, Joseph E. Pasciak

Mathematics and Statistics Faculty Publications and Presentations

We investigate some simple finite element discretizations for the axisymmetric Laplace equation and the azimuthal component of the axisymmetric Maxwell equations as well as multigrid algorithms for these discretizations. Our analysis is targeted at simple model problems and our main result is that the standard V-cycle with point smoothing converges at a rate independent of the number of unknowns. This is contrary to suggestions in the existing literature that line relaxations and semicoarsening are needed in multigrid algorithms to overcome difficulties caused by the singularities in the axisymmetric Maxwell problems. Our multigrid analysis proceeds by applying the well known regularity …


Puncturing Ability Of Idealized Canine Teeth: Edged And Non-Edged Shanks, Patricia W. Freeman, Cliff A. Lemen Jan 2006

Puncturing Ability Of Idealized Canine Teeth: Edged And Non-Edged Shanks, Patricia W. Freeman, Cliff A. Lemen

School of Natural Resources: Faculty Publications

Idealized edged and non-edged indenters, mimicking canine teeth, were used to puncture thin materials and thick materials. Less force was needed for the edged (triangular in cross section) indenter to penetrate thin Mylar, paper, leather, beetle elytra and turkey skin than the non-edged (circular in cross-section) indenter. Oak, grass and magnolia leaves responded equally to both indenters. In thick materials, the edged indenter punctured beetles, shrimp, bananas, and chicken flesh more easily than the non-edged indenter. Apple, tomato and avocado were punctured equally well. The edged indenter directs cracks at the corners so that the material can fold away in …


The Geoprofile Metadata, Exposure Of Instruments, And Measurement Bias In Climatic Record Revisited, Rezaul Mahmood Jan 2006

The Geoprofile Metadata, Exposure Of Instruments, And Measurement Bias In Climatic Record Revisited, Rezaul Mahmood

School of Natural Resources: Faculty Publications

No abstract provided.


Role Of Anomalous Warm Gulf Waters In The Intensification Of Hurricane Katrina, Menas Kafatos, D. Sun, Ritesh Gautam, Z. Boybeyi, Ruixin Yang, G. Cervone Jan 2006

Role Of Anomalous Warm Gulf Waters In The Intensification Of Hurricane Katrina, Menas Kafatos, D. Sun, Ritesh Gautam, Z. Boybeyi, Ruixin Yang, G. Cervone

Mathematics, Physics, and Computer Science Faculty Articles and Research

The year 2005 experienced several strong hurricanes intensifying in the Gulf of Mexico before making landfall that severely damaged the Gulf States, especially Hurricane Katrina. Remarkable similarities between sea surface temperature anomaly (SSTA) and major hurricane (categories 3 and higher) activity over the Gulf are identified. However, the intensification of individual hurricanes may not necessarily be temporally and spatially coincident with the distribution of warm waters or high sea surface temperature (SST). High SST values are found in advance of significant intensification of Hurricane Katrina. We emphasize that high SSTA which occurred at the right time and right place was …


Diurnal Temperature Range Over The United States: A Satellite View, D. Sun, R. T. Pinker, Menas Kafatos Jan 2006

Diurnal Temperature Range Over The United States: A Satellite View, D. Sun, R. T. Pinker, Menas Kafatos

Mathematics, Physics, and Computer Science Faculty Articles and Research

Diurnal temperature range (DTR) is an important climate change index. Information on this parameter comes primarily from sparse and unevenly distributed observations of shelter air temperature. In this study, five years of GOES- 8 based estimates of land surface temperature (LST) over the United States are used to evaluate DTR at high spatial resolution. The spatial and temporal patterns that emerged show a high degree of consistency with independent satellite estimates of the Normalized Difference Vegetation Index (NDVI). Specifically, the arid regions in the western and central U.S. have larger DTRs than the eastern United States or the northwest coast. …


Handling The Subclassing Anomaly With Object Teams, Jeff Furlong, Atanas Radenski Jan 2006

Handling The Subclassing Anomaly With Object Teams, Jeff Furlong, Atanas Radenski

Mathematics, Physics, and Computer Science Faculty Articles and Research

Existing Java software or libraries can evolve via subclassing. Unfortunately, subclassing may not properly support code adaptation when there are dependencies between classes. More precisely, subclassing in collections of related classes may require reimplementation of otherwise valid classes. This problem is defined as the subclassing anomaly, which is an issue when software evolution or code reuse is a goal of the programmer who is using existing classes. Object Teams offers an implicit fix to this problem and is largely compatible with the existing JVM’s. In this paper, we evaluate how well Object Teams succeeds in providing a solution for a …


Matrix-J-Unitary Non-Commutative Rational Formal Power Series, Daniel Alpay, D. S. Kalyuzhnyi-Verbovetzkii Jan 2006

Matrix-J-Unitary Non-Commutative Rational Formal Power Series, Daniel Alpay, D. S. Kalyuzhnyi-Verbovetzkii

Mathematics, Physics, and Computer Science Faculty Articles and Research

Formal power series in N non-commuting indeterminates can be considered as a counterpart of functions of one variable holomorphic at 0, and some of their properties are described in terms of coefficients. However, really fruitful analysis begins when one considers for them evaluations on N-tuples of n × n matrices (with n = 1, 2, . . .) or operators on an infinite-dimensional separable Hilbert space. Moreover, such evaluations appear in control, optimization and stabilization problems of modern system engineering.

In this paper, a theory of realization and minimal factorization of rational matrix-valued functions which are J-unitary on the imaginary …