Open Access. Powered by Scholars. Published by Universities.®

Digital Commons Network™

Open Access. Powered by Scholars. Published by Universities.®

Faculty Publications

Discipline
Institution
Keyword
Publication Year
File Type

Articles 6481 - 6510 of 9022

Full-Text Articles in Entire DC Network

Beating The Spin-Down Limit On Gravitational Wave Emission From The Crab Pulsar, B. Abbott, R. Abbott, R. Adhikari, P. Ajith, B. Allen, G. Allen, R. Amin, S. B. Anderson, W. G. Anderson, M. A. Arain, M. Araya, H. Armandula, P. Armor, Y. Aso, S. Aston, P. Aufmuth, C. Aulbert, S. Babak, S. Ballmer, H. Bantilan, B. C. Barish, C. Barker, D. Barker, B. Barr, P. Barriga, M. A. Barton, M. Bastarrika, K. Bayer, J. Betzwieser, P. T. Beyersdorf, I. A. Bilenko, Tiffany Z. Summerscales Jan 2008

Beating The Spin-Down Limit On Gravitational Wave Emission From The Crab Pulsar, B. Abbott, R. Abbott, R. Adhikari, P. Ajith, B. Allen, G. Allen, R. Amin, S. B. Anderson, W. G. Anderson, M. A. Arain, M. Araya, H. Armandula, P. Armor, Y. Aso, S. Aston, P. Aufmuth, C. Aulbert, S. Babak, S. Ballmer, H. Bantilan, B. C. Barish, C. Barker, D. Barker, B. Barr, P. Barriga, M. A. Barton, M. Bastarrika, K. Bayer, J. Betzwieser, P. T. Beyersdorf, I. A. Bilenko, Tiffany Z. Summerscales

Faculty Publications

We present direct upper limits on gravitational wave emission from the Crab pulsar using data from the first 9 months of the fifth science run of the Laser Interferometer Gravitational-wave Observatory (LIGO). These limits are based on two searches. In the first we assume that the gravitational wave emission follows the observed radio timing, giving an upper limit on gravitational wave emission that beats indirect limits inferred from the spin-down and braking index of the pulsar and the energetics of the nebula. In the second we allow for a small mismatch between the gravitational and radio signal frequencies and interpret …


First Joint Search For Gravitational-Wave Bursts In Ligo And Geo 600 Data, B. Abbott, R. Abbott, R. Adhikari, P. Ajith, B. Allen, G. Allen, R. Amin, S. B. Anderson, W. G. Anderson, M. A. Arain, M. Araya, H. Armandula, P. Armor, Y. Aso, S. Aston, P. Aufmuth, C. Aulbert, S. Babak, S. Ballmer, H. Bantilan, B. C. Barish, C. Barker, D. Barker, B. Barr, P. Barriga, M. A. Barton, I. Bartos, M. Bastarrika, K. Bayer, J. Betzwieser, P. T. Beyersdorf, Tiffany Z. Summerscales Jan 2008

First Joint Search For Gravitational-Wave Bursts In Ligo And Geo 600 Data, B. Abbott, R. Abbott, R. Adhikari, P. Ajith, B. Allen, G. Allen, R. Amin, S. B. Anderson, W. G. Anderson, M. A. Arain, M. Araya, H. Armandula, P. Armor, Y. Aso, S. Aston, P. Aufmuth, C. Aulbert, S. Babak, S. Ballmer, H. Bantilan, B. C. Barish, C. Barker, D. Barker, B. Barr, P. Barriga, M. A. Barton, I. Bartos, M. Bastarrika, K. Bayer, J. Betzwieser, P. T. Beyersdorf, Tiffany Z. Summerscales

Faculty Publications

We present the results of the first joint search for gravitational-wave bursts by the LIGO and GEO 600 detectors. We search for bursts with characteristic central frequencies in the band 768-2048 Hz in the data acquired between 22 February and 23 March, 2005 (fourth LSC Science Run-S4). We discuss the inclusion of the GEO 600 data in the Waveburst-CorrPower pipeline that first searches for coincident excess power events without taking into account differences in the antenna responses or strain sensitivities of the various detectors. We compare the performance of this pipeline to that of the coherent Waveburst pipeline based on …


Learning Policies For Embodied Virtual Agents Through Demonstration, Jonathan Dinerstein, Parris K. Egbert, Dan A. Ventura Jan 2008

Learning Policies For Embodied Virtual Agents Through Demonstration, Jonathan Dinerstein, Parris K. Egbert, Dan A. Ventura

Faculty Publications

Although many powerful AI and machine learning techniques exist, it remains difficult to quickly create AI for embodied virtual agents that produces visually lifelike behavior. This is important for applications (e.g., games, simulators, interactive displays) where an agent must behave in a manner that appears human-like. We present a novel technique for learning reactive policies that mimic demonstrated human behavior. The user demonstrates the desired behavior by dictating the agent’s actions during an interactive animation. Later, when the agent is to behave autonomously, the recorded data is generalized to form a continuous state-to-action mapping. Combined with an appropriate animation algorithm …


Performance Comparison Of Pb(Zr0.52Ti0.48)O3-Only And Pb(Zr0.52Ti0.48)O3-On-Silicon Resonators, Hengky Chandrahalim, Sunil A. Bhave, Ronald G. Polcawich, Jeff Pulskamp, Dan Judy, Roger Kaul, Madan Dubey Jan 2008

Performance Comparison Of Pb(Zr0.52Ti0.48)O3-Only And Pb(Zr0.52Ti0.48)O3-On-Silicon Resonators, Hengky Chandrahalim, Sunil A. Bhave, Ronald G. Polcawich, Jeff Pulskamp, Dan Judy, Roger Kaul, Madan Dubey

Faculty Publications

This paper provides a quantitative comparison and explores the design space of lead zirconium titanate (PZT)–only and PZT-on-silicon length-extensional mode resonators for incorporation into radio frequency microelectromechanical system filters and oscillators. We experimentally measured the correlation of motional impedance (RX) and quality factor (Q) with the resonators’ silicon layer thickness (tSi). For identical lateral dimensions and PZT-layer thicknesses (tPZT), the PZT-on-silicon resonator has higher resonant frequency (fC), higher Q (5100 versus 140), lower RX (51 Ω versus 205 Ω), and better linearity [third-order input intercept …


The Path Not Taken: French Industrialization In The Age Of Revolution, 1750-1830, By Jeff Horn, Michael S. Smith Jan 2008

The Path Not Taken: French Industrialization In The Age Of Revolution, 1750-1830, By Jeff Horn, Michael S. Smith

Faculty Publications

A review of The Path Not Taken: French Industrialization in the Age of Revolution, 1750-1830, by Jeff Horn


Combinatorial Investigation Of Magnetostriction In Fe-Fa And Fe-Ga-Al, Jason R. Hattrick-Simpers, Dwight Hunter, Corneliu M. Craciunescu, Kyu Sung Jang, Makoto Murakami, James Cullen, Manfred Wuttig, Ichiro Takeuchi, Samuel E. Lofland, Leonid Bendersky, Noble Woo, Robert Bruce Vandover, Toshiya Takahashi, Yasubumi Furuya Jan 2008

Combinatorial Investigation Of Magnetostriction In Fe-Fa And Fe-Ga-Al, Jason R. Hattrick-Simpers, Dwight Hunter, Corneliu M. Craciunescu, Kyu Sung Jang, Makoto Murakami, James Cullen, Manfred Wuttig, Ichiro Takeuchi, Samuel E. Lofland, Leonid Bendersky, Noble Woo, Robert Bruce Vandover, Toshiya Takahashi, Yasubumi Furuya

Faculty Publications

A high-throughput high-sensitivity optical technique for measuringmagnetostriction of thin-film composition-spread samples has been developed. It determines the magnetostriction by measuring the induced deflection of micromachined cantilever unimorph samples. Magnetostrictionmeasurements have been performed on as-deposited Fe–Ga and Fe–Ga–Al thin-film composition spreads. The thin-film Fe–Ga spreads display a similar compositional variation of magnetostriction as bulk. A previously undiscovered peak in magnetostriction at low Ga content was also observed and attributed to a maximum in the magnetocrystalline anisotropy. Magnetostrictive mapping of the Fe–Ga–Al ternary system reveals the possibility of substituting up to 8at.%Al in Fe70Ga30 without significant degradation of magnetostriction.


High-Throughput Screening Of Shape Memory Alloy Thin-Film Spreads Using Nanoindentation, Arpit Dwivedi, Thomas J. Wyrobek, Oden L. Warren, Jason R. Hattrick-Simpers, Olubenga O. Famodu, Ichiro Takeuchi Jan 2008

High-Throughput Screening Of Shape Memory Alloy Thin-Film Spreads Using Nanoindentation, Arpit Dwivedi, Thomas J. Wyrobek, Oden L. Warren, Jason R. Hattrick-Simpers, Olubenga O. Famodu, Ichiro Takeuchi

Faculty Publications

We have demonstrated the utility of nanoindentation as a rapid characterization tool for mapping shape memoryalloy compositions in combinatorial thin-film libraries. Nanoindentation was performed on Ni–Mn–Al ternary composition spreads. The indentation hardness and the reduced elastic modulus were mapped across a large fraction of the ternary phase diagram. The large shape memoryalloy composition region, located around the Heusler composition (Ni2MnAl), was found to display significant departure in these mechanical properties from the rest of the composition spread. In particular, the modulus and the hardness values are lower for the martensite region than those of the rest of the …


Alternative Parametric Boundary Reconstruction Method For Biomedical Imaging, Joseph Kolibal, Daniel Howard Jan 2008

Alternative Parametric Boundary Reconstruction Method For Biomedical Imaging, Joseph Kolibal, Daniel Howard

Faculty Publications

Determining the outline or boundary contour of a two-dimensional object, or the surface of a three-dimensional object poses difficulties particularly when there is substantial measurement noise or uncertainty. By adapting the mathematical approach of stochastic function recovery to this task, it is possible to obtain usable estimates for these boundaries, even in the presence of large amounts of noise. The technique is applied to parametric boundary data and has potential applications in biomedical imaging. It should be considered as one of several techniques to improve the visualization of images. Copyright (C) 2008 J. Kolibal and D. Howard.


Unusual Digital Patterns In Eps: Evidence On The Association Between Earnings Management And Company Characteristics, Charles E. Jordan, Stanley J. Clark, Mary M. Anderson Jan 2008

Unusual Digital Patterns In Eps: Evidence On The Association Between Earnings Management And Company Characteristics, Charles E. Jordan, Stanley J. Clark, Mary M. Anderson

Faculty Publications

Prior studies (Thomas, 1989; Das and Zhang, 2003) provide evidence of earnings manipulation to achieve cognitive reference points in EPS. The current study extends this line of research by examining the relation between unusual digital patterns in the right EPS position and specific firm characteristics. Results suggest that the propensity to manage earnings to effect desired EPS results is particularly associated with company size and to a lesser degree with operating performance and the level of debt leverage employed.


The Wheel Garden: Project Based Learning For Cross Curriculum Education, Sherry S. Herron, Douglas Magomo, Paula Rae Gossard Jan 2008

The Wheel Garden: Project Based Learning For Cross Curriculum Education, Sherry S. Herron, Douglas Magomo, Paula Rae Gossard

Faculty Publications

In this article, we discuss project-based learning in the context of a wheel garden as an instructional tool in science and mathematics education. A wheel garden provides multiple opportunities to teach across the curriculum, to integrate disciplines, and to promote community involvement. Grounded in the theoretical framework of constructivism, the wheel garden provides a multidisciplined educational tool that provides a hands-on, non-traditional arena for learning. We will examine some of the cultural, art, science, and mathematics connections made with this project


A Clustering Approach For The Separation Of Touching Edges In Particle Images, Jose M. Korath, Ali Abbas, Jose A. Romagnoli Jan 2008

A Clustering Approach For The Separation Of Touching Edges In Particle Images, Jose M. Korath, Ali Abbas, Jose A. Romagnoli

Faculty Publications

The occurrence of touching objects in images of particulate systems is very common especially in the absence of dispersion methods during image acquisition. The separation of these touching particles is essential before accurate estimation of particle size and shape can be achieved from these images. In the current work, clustering approaches based on the fuzzy C-means algorithm are employed to identify the touching particle regions. Firstly, clustering in the multidimensional space of image features, e.g., standard deviation, gradient and range calculated in a certain neighborhood of each pixel, is performed to trap the touching regions. Then, in a novel proposed …


Tetra-μ-Aqua-Octaaquabis(μ-4-Chloropyridine-2,6-Dicarboxylato(Bis(4-Chloro-Pyridine-2,6-Dicarboxylato)Tricobalt(Ii)-Disodium(I) Bis[Triaquabis(4-Chloro-Pyridine-2,6-Dicarboxylato)Cobalt(Ii)] Hexahydrate, Lamaryet Moody, Shawna Balof, Shanika Smith, Varma H. Rambaran, Don Vanderveer, Alvin A. Holder Jan 2008

Tetra-μ-Aqua-Octaaquabis(μ-4-Chloropyridine-2,6-Dicarboxylato(Bis(4-Chloro-Pyridine-2,6-Dicarboxylato)Tricobalt(Ii)-Disodium(I) Bis[Triaquabis(4-Chloro-Pyridine-2,6-Dicarboxylato)Cobalt(Ii)] Hexahydrate, Lamaryet Moody, Shawna Balof, Shanika Smith, Varma H. Rambaran, Don Vanderveer, Alvin A. Holder

Faculty Publications

The title compound, [Co3Na2(C72ClNO4)4(H2O)12][Co(C7H2ClNO4(H2O)3]2·6H2O, consists of a centrosymmetric dimer of [CoII(dipicCl)2]2- complex dianions [dipicCl is 4-chloro­pyridine-2,6-dicarboxyl­ate] bridged by an [Na2CoII(H2O)12]4+ tetra­cationic cluster, two independent [Co(dipicCl)(H2O)3] complexes, and six water mol­ecules of crystallization. The metals are all six-coordinate with distorted octahedral geometries. The [CoII(dipicCl)(H2O)3] complexes are neutral, with …


Use Of Trees By The Texas Ratsnake (Elaphe Obsoleta) In Eastern Texas, Josh B. Pierce, Robert R. Fleet, Lance Mcbrayer, D. Craig Rudolph Jan 2008

Use Of Trees By The Texas Ratsnake (Elaphe Obsoleta) In Eastern Texas, Josh B. Pierce, Robert R. Fleet, Lance Mcbrayer, D. Craig Rudolph

Faculty Publications

We present information on the use of trees by Elaphe obsoleta (Texas Ratsnake) in a mesic pine-hardwood forest in eastern Texas. Using radiotelemetry, seven snakes (3 females, 4 males) were relocated a total of 363 times from April 2004 to May 2005, resulting in 201 unique locations. Snakes selected trees containing cavities and used hardwoods and snags for a combined 95% of arboreal locations. Texas Ratsnake arboreal activity peaked during July and August, well after the peak of avian breeding activity, suggesting arboreal activity involves factors other than avian predation.


Delta Function For An Affine Subspace, Jeremy Becnel Jan 2008

Delta Function For An Affine Subspace, Jeremy Becnel

Faculty Publications

The Kubo–Yokoi and Donsker delta functions are well known generalized functions in infinite dimensional distribution theory. In this paper we develop the delta function for an affine subspace and show that it is a generalization of the Kubo–Yokoi and Donsker delta functions. The Wiener– Itˆo expansion of the delta function for an affine subspace is also given.


Privacy And Funeral Protests, Christina E. Wells Jan 2008

Privacy And Funeral Protests, Christina E. Wells

Faculty Publications

This article examines the free speech implications of funeral protest statutes. Enacted in response to the Westboro Baptist Church, whose members protest at funerals to spread their antigay message, such statutes restrict a broad array of peaceful expressive activity. This Article focuses on the states’ interest underlying these statutes - protecting mourners’ right to be free from unwanted intrusions while at funeral services. Few would argue against protecting funeral services from intrusive protests. These statutes, however, go far beyond that notion and protect mourners from offensive, rather than intrusive, protests. As such, they do not conceive of privacy as protection …


The Future Of The Economic Analysis Of Law In Latin America: A Proposal For Model Codes, Juan Javier Del Granado, M C. Mirow Jan 2008

The Future Of The Economic Analysis Of Law In Latin America: A Proposal For Model Codes, Juan Javier Del Granado, M C. Mirow

Faculty Publications

Nothing excites civilian lawyers and judges more than commissions for codification. Codification is more than an academic enterprise. Codification projects directly cut across the interface between law and life. ALACDE intends to harness this Latin American interest in codification to bring the economic approach to Latin America. A new-generation law and economics civil and commercial code will be a conscious project to restate Roman law's usefulness for coping with today's problems. Through law and economics, Roman law will renew itself. As a paradigmatic private-law system, Roman law is eminently amenable to a state-of-the-art fusion with law and economics. Sensitivity to …


Polymorphisms In Methionine Synthase, Methionine Synthase Reductase And Serine Hydroxymethyltransferase, Folate And Alcohol Intake, And Colon Cancer Risk, Susan E. Steck, Temitope O. Keku, Lesley M. Butler, Joseph Galanko, Beri Massa, Robert C. Millikan, Robert S. Sandler Jan 2008

Polymorphisms In Methionine Synthase, Methionine Synthase Reductase And Serine Hydroxymethyltransferase, Folate And Alcohol Intake, And Colon Cancer Risk, Susan E. Steck, Temitope O. Keku, Lesley M. Butler, Joseph Galanko, Beri Massa, Robert C. Millikan, Robert S. Sandler

Faculty Publications

Background/Aims - We examined associations among folate and alcohol intake, SNPs in genes involved in one-carbon metabolism and colon cancer risk.

Methods - Colon cancer cases (294 African Americans and 349 whites) were frequency matched to population controls (437 African Americans and 611 whites) by age, race and sex from 33 North Carolina counties from 1996 to 2000. Folate and alcohol intakes were collected by dietary interview. Five SNPs were genotyped using DNA from whole blood: SHMT C1420T; MTRR A66G; MTR A2756G, and the previously-reported MTHFR C677T and MTHFR A1298C. Adjusted odds ratios (OR) and 95% …


Parameter Estimation And Life Modeling Of Lithium-Ion Cells, Shriram Santhanagopalan, Qi Zhang, Karthikeyan Kumaresan, Ralph E. White Jan 2008

Parameter Estimation And Life Modeling Of Lithium-Ion Cells, Shriram Santhanagopalan, Qi Zhang, Karthikeyan Kumaresan, Ralph E. White

Faculty Publications

Lithium-ion pouch cells were cycled at five different temperatures (5, 15, 25, 35, and 45°C ), and rate capability studies were performed after every hundred cycles. The data were used with a simple physics-based model to estimate parameters that capture the capacity fade in the cell, with cycling. The weight of active material within each electrode was estimated as a function of time, using rate capability data at the C/33 rate. The C-rate for these cells is 1.656 A. The capacity fade due to the loss of active material and that due to the loss of cyclable lithium …


Thermal Model For A Li-Ion Cell, Karthikeyan Kumaresan, Godfrey Sikha, Ralph E. White Jan 2008

Thermal Model For A Li-Ion Cell, Karthikeyan Kumaresan, Godfrey Sikha, Ralph E. White

Faculty Publications

A thermal model for a lithium-ion cell is presented and used to predict discharge performance at different operating temperatures. The results from the simulations are compared to experimental data obtained from lithium-ion pouch cells. The model includes a set of parameters (and their concentration and temperature dependencies) that has been obtained for a lithium-ion cell composed of a mesocarbon microbead anode, LiCoO2 cathode in 1 M LiPF6 salt, in a mixture of ethylene carbonate, propylene carbonate, ethyl-methyl carbonate, and diethyl carbonate electrolyte. The parameter set was obtained by comparing the model predictions to the experimental discharge profiles obtained …


Analytical Expression For The Impedance Response For A Lithium-Ion Cell, Godfrey Sikha, Ralph E. White Jan 2008

Analytical Expression For The Impedance Response For A Lithium-Ion Cell, Godfrey Sikha, Ralph E. White

Faculty Publications

An analytical expression to predict the impedance response of a dual insertion electrode cell (insertion electrodes separated by an ionically conducting membrane) is presented. The expression accounts for the reaction kinetics and double-layer adsorption processes at the electrode-electrolyte interface, transport of electroactive species in the electrolyte phase, and insertion of species in the solid phase of the insertion electrodes. The accuracy of the analytical expression is validated by comparing the impedance response predicted by the expression to the corresponding numerical solution. The analytical expression is used to predict the impedance response of a lithium-ion cell consisting of a porous LiCoO …


A Mathematical Model For A Lithium–Sulfur Cell, Karthikeyan Kumaresan, Yuriy Mikhaylik, Ralph E. White Jan 2008

A Mathematical Model For A Lithium–Sulfur Cell, Karthikeyan Kumaresan, Yuriy Mikhaylik, Ralph E. White

Faculty Publications

A mathematical model is presented for a complete lithium–sulfur cell. The model includes various electrochemical and chemical (precipitation) reactions, multicomponent transport phenomena in the electrolyte, and the charge transfer within and between solid and liquid phases. A change in the porosity of the porous cathode and separator due to precipitation reactions is also included in the model. The model is used to explain the physical reasons for the two-stage discharge profiles that are typically obtained for lithium–sulfur cells.


Evaluating Forest Harvesting To Reduce Its Hydrologic Impact With A Spatial Decision Support System, Yanli Zhang, P. K. Barten, Ramanathan Sugumaran Jan 2008

Evaluating Forest Harvesting To Reduce Its Hydrologic Impact With A Spatial Decision Support System, Yanli Zhang, P. K. Barten, Ramanathan Sugumaran

Faculty Publications

Timber harvesting changes the condition of forest ecosystems, which are a major influence on the characteristics of headwater streams. Such characteristics include the quantity and timing of base flow and storm flow, concentrations of sediment and dissolved nutrients, water temperature, and the stability of the stream channels. This paper explores previous studies dealing with the relationship between timber harvesting and its hydrologic effects, especially long term water yield increase. The watershed disturbance threshold theory is raised and investigated in detail. The development and evaluation of a spatial decision support system, the Harvest Schedule Review System (HSRS), is then described. The …


Narcissism, Over-Optimism, Fear, Anger, And Depression: The Interior Lives Of Corporate Leaders, Jayne W. Barnard Jan 2008

Narcissism, Over-Optimism, Fear, Anger, And Depression: The Interior Lives Of Corporate Leaders, Jayne W. Barnard

Faculty Publications

No abstract provided.


Personal Integration And Outsider Status As Factors In Law Student Well-Being, Susan Grover Jan 2008

Personal Integration And Outsider Status As Factors In Law Student Well-Being, Susan Grover

Faculty Publications

No abstract provided.


Ideological Cohesion And Precedent (Or Why The Court Only Cares About Precedent When Most Justices Agree With Each Other), Neal Devins Jan 2008

Ideological Cohesion And Precedent (Or Why The Court Only Cares About Precedent When Most Justices Agree With Each Other), Neal Devins

Faculty Publications

This Article examines the profound role that ideological cohesion plays in explaining the Supreme Court's willingness to advance a coherent vision of the law - either by overruling precedents inconsistent with that vision or by establishing rule-like precedents intended to bind the Supreme Court and lower courts in subsequent cases. Through case studies of the New Deal, Warren, and Rehnquist Courts, this Article calls attention to key differences between Courts in which five or more Justices pursue the same substantive objectives and Courts which lack a dominant voting block. In particular, when five or more Justices pursue the same substantive …


Constructing An Ethic Of Care In Teacher Education: Narrative As Pedagogy Toward Care, Colette Rabin Jan 2008

Constructing An Ethic Of Care In Teacher Education: Narrative As Pedagogy Toward Care, Colette Rabin

Faculty Publications

Teacher educators have a civic responsibility to prepare novice teachers to foster relationships across cultural, racial, and socioeconomic divides. Care ethics acknowledges this imperative. This study explores how to cultivate the knowledge, skills and dispositions associated with constructing a caring stance toward the work of teaching. Data come from two preservice teacher education courses. A cluster of course activities sought to foster novice teachers’ core skills for a caring stance. In particular, one assignment, an ethical dilemma case, gave the novice teachers the opportunity to write a narrative about practice and consider any potential moral implications. Since narrative methodology accounts …


Evidence Contrary To The Statistical View Of Boosting, David Mease, A. Wyner Jan 2008

Evidence Contrary To The Statistical View Of Boosting, David Mease, A. Wyner

Faculty Publications

The statistical perspective on boosting algorithms focuses on optimization, drawing parallels with maximum likelihood estimation for logistic regression. In this paper we present empirical evidence that raises questions about this view. Although the statistical perspective provides a theoretical framework within which it is possible to derive theorems and create new algorithms in general contexts, we show that there remain many unanswered important questions. Furthermore, we provide examples that reveal crucial flaws in the many practical suggestions and new methods that are derived from the statistical view. We perform carefully designed experiments using simple simulation models to illustrate some of these …


Testing The Nature Of S0 Galaxies Using Planetary Nebula Kinematics In Ngc 1023, E. Noordermeer, M. R. Merrifield, L. Coccato, M. Arnaboldi, M. Capaccioli, N. G. Douglas, K. C. Freeman, O. Gerhard, K. Kuijken, F. De Lorenzi, N. R. Napolitano, Aaron J. Romanowsky Jan 2008

Testing The Nature Of S0 Galaxies Using Planetary Nebula Kinematics In Ngc 1023, E. Noordermeer, M. R. Merrifield, L. Coccato, M. Arnaboldi, M. Capaccioli, N. G. Douglas, K. C. Freeman, O. Gerhard, K. Kuijken, F. De Lorenzi, N. R. Napolitano, Aaron J. Romanowsky

Faculty Publications

We investigate the manner in which lenticular galaxies are formed by studying their stellar kinematics: an S0 formed from a fading spiral galaxy should display similar cold outer disc kinematics to its progenitor, while an S0 formed in a minor merger should be more dominated by random motions. In a pilot study, an attempt to distinguish between these scenarios, we have measured the planetary nebula (PN) kinematics of the nearby S0 system NGC 1023. Using the Planetary Nebula Spectrograph, we have detected and measured the line-of-sight velocities of 204 candidate planetary nebulae (PNe) in the field of this galaxy. Out …


Stochastic Hard-Sphere Dynamics For Hydrodynamics Of Non-Ideal Fluids, Alejandro Garcia, A. Donev, B. J. Alder Jan 2008

Stochastic Hard-Sphere Dynamics For Hydrodynamics Of Non-Ideal Fluids, Alejandro Garcia, A. Donev, B. J. Alder

Faculty Publications

A novel stochastic fluid model is proposed with a nonideal structure factor consistent with compressibility, and adjustable transport coefficients. This stochastic hard sphere dynamics (SHSD) algorithm is a modification of the direct simulation Monte Carlo algorithm and has several computational advantages over event-driven hard-sphere molecular dynamics. Surprisingly, SHSD results in an equation of state and a pair correlation function identical to that of a deterministic Hamiltonian system of penetrable spheres interacting with linear core pair potentials. The fluctuating hydrodynamic behavior of the SHSD fluid is verified for the Brownian motion of a nanoparticle suspended in a compressible solvent.


Elastic Wave Field Computation In Multilayered Nonplanar Solid Structures: A Mesh-Free Semianalytical Approach, Sourav Banerjee, Tribikram Kundu Jan 2008

Elastic Wave Field Computation In Multilayered Nonplanar Solid Structures: A Mesh-Free Semianalytical Approach, Sourav Banerjee, Tribikram Kundu

Faculty Publications

Multilayered solid structures made of isotropic, transversely isotropic, or general anisotropic materials are frequently used in aerospace, mechanical, and civil structures. Ultrasonic fields developed in such structures by finite size transducers simulating actual experiments in laboratories or in the field have not been rigorously studied. Several attempts to compute the ultrasonic field inside solid media have been made based on approximate paraxial methods like the classical ray tracing and multi-Gaussian beam models. These approximate methods have several limitations. A new semianalytical method is adopted in this article to model elastic wave field in multilayered solid structures with planar or nonplanar …