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Articles 31831 - 31860 of 36568

Full-Text Articles in Physical Sciences and Mathematics

Quantum Version Of A Spherical Model: Crossover From Quantum To Classical Critical Behavior, Thomas Vojta Jan 1996

Quantum Version Of A Spherical Model: Crossover From Quantum To Classical Critical Behavior, Thomas Vojta

Physics Faculty Research & Creative Works

We investigate a quantum version of the spherical model which is obtained from the classical Berlin-Kac spherical model by a simple canonical quantization scheme. We find a complete solution of the model for short-range as well as for long-range interactions. At finite temperatures the critical behavior is the same as in the classical spherical model whereas at zero temperature we find a quantum phase transition characterized by new critical exponents. Based on a functional-integral representation of the partition function the free energy of the model is shown to be equivalent to that of the nonlinear σ model in the limit …

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Optical Electron Polarimetry With Heavy Noble Gases, Timothy James Gay, J. E. Furst, K. W. Trantham, W. M.K.P. Wijayaratna Jan 1996

Optical Electron Polarimetry With Heavy Noble Gases, Timothy James Gay, J. E. Furst, K. W. Trantham, W. M.K.P. Wijayaratna

Physics Faculty Research & Creative Works

We have measured the polarization of fluorescence emitted by the noble gases He, Ne, Ar, Kr, and Xe following impact excitation by polarized electrons. In He, the [Formula Presented]P→[Formula Presented]S transition was studied; in the heavy noble gases the [Formula Presented](n+1)p[Formula Presented]→[Formula Presented](n+1)s[Formula Presented] transitions were analyzed. We investigated these transitions as candidates for efficient optical electron polarimetry and found that, because of their larger excitation cross sections and analyzing power, the heavy noble gases are superior to He, which had been used previously as a polarimetric target. Several issues with regard to the implementation and accuracy of optical electron …

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Collective Behavior Of Electrons Emitted In Multiply Ionizing Collisions Of 5.9 Mev/U U⁶⁵⁺ With Ne, M. Unverzagt, R. Moshammer, W. Schmitt, Ronald E. Olson, P. Jardin, V. Mergel, J. Ullrich, H. Schmidt-Böcking Jan 1996

Collective Behavior Of Electrons Emitted In Multiply Ionizing Collisions Of 5.9 Mev/U U⁶⁵⁺ With Ne, M. Unverzagt, R. Moshammer, W. Schmitt, Ronald E. Olson, P. Jardin, V. Mergel, J. Ullrich, H. Schmidt-Böcking

Physics Faculty Research & Creative Works

The collective behavior of up to six target electrons emitted in a single collision of 5.9 MeV/u U65+ with Ne was investigated using high-resolution recoil-ion momentum spectroscopy. With an increasing number of ejected electrons the recoil ions are increasingly scattered into the backward direction, providing evidence that the electrons are emitted into the forward hemisphere. Their mean longitudinal sum energy varies from about 5 eV for single ionization up to 1.1 keV for Ne6+. Experimental recoil-ion momentum distributions are in excellent agreement with results of classical many-particle calculations. © 1996 The American Physical Society.

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Effective-Medium Theory For The Electric-Field Dependence Of The Hopping Conductivity Of Disordered Solids, Paul Ernest Parris, B. D. Bookout Jan 1996

Effective-Medium Theory For The Electric-Field Dependence Of The Hopping Conductivity Of Disordered Solids, Paul Ernest Parris, B. D. Bookout

Physics Faculty Research & Creative Works

We derive a general effective-medium theory for describing biased diffusion on a bond-disordered lattice in the presence of an external driving field. In our theory, the effective medium associated with a disordered d-dimensional lattice is characterized, for each value of the applied field, by 2d independent parameters describing, respectively, the net drift velocity vv and the diffusion constant Dvv describing the spread of a carrier packet about its mean value, for each of the d crystal axes. The theory correctly predicts the velocity transition occurring in an exactly soluble model studied by Derrida and, in contrast to other …

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Deep Inelastic Scattering Of Polarized Electrons By Polarized ³He And The Study Of The Neutron Spin Structure, P. L. Anthony, R. G. Arnold, H. R. Band, H. Borel, P. E. Bosted, V. Breton, G. D. Cates, T. E. Chupp, F. S. Dietrich, J. Dunne, R. Erbacher, J. Felbauum, H. Fonvielle, R. Gearhart, R. Holmes, E. W. Hughes, J. R. Johnson, D. Kawall, C. Keppel, S. E. Kuhn, R. M. Lombard-Nelsen, J. Marroncle, T. Maruyama, W. Meyer, Z.- E. Meziani, H. Middleton, J. Morgenstern, N. R. Newbury, G. G. Petratos, R Pitthan, R. Prepost, Y. Robin, S. E. Rock, S. H. Rokni, G. Shapiro, T. Smith, P. A. Souder, M. Spengos, F. Staley, L. M. Stuart, Z. M. Szlata, Y. Terrien, A. K. Thompson, J. L. White, M. Woods, J. Xu, C. C. Young, G. Zaplac, E142 Collaboration Jan 1996

Deep Inelastic Scattering Of Polarized Electrons By Polarized ³He And The Study Of The Neutron Spin Structure, P. L. Anthony, R. G. Arnold, H. R. Band, H. Borel, P. E. Bosted, V. Breton, G. D. Cates, T. E. Chupp, F. S. Dietrich, J. Dunne, R. Erbacher, J. Felbauum, H. Fonvielle, R. Gearhart, R. Holmes, E. W. Hughes, J. R. Johnson, D. Kawall, C. Keppel, S. E. Kuhn, R. M. Lombard-Nelsen, J. Marroncle, T. Maruyama, W. Meyer, Z.- E. Meziani, H. Middleton, J. Morgenstern, N. R. Newbury, G. G. Petratos, R Pitthan, R. Prepost, Y. Robin, S. E. Rock, S. H. Rokni, G. Shapiro, T. Smith, P. A. Souder, M. Spengos, F. Staley, L. M. Stuart, Z. M. Szlata, Y. Terrien, A. K. Thompson, J. L. White, M. Woods, J. Xu, C. C. Young, G. Zaplac, E142 Collaboration

Physics Faculty Publications

The neutron longitudinal and transverse asymmetries A1n and A2n have been extracted from deep inelastic scattering of polarized electrons by a polarized 3He target at incident energies of 19.42, 22.66, and 25.51 GeV. The measurement allows for the determination of the neutron spin structure functions g1n (x,Q2) and g2n(x,Q2) over the range 0.032 of 2 (GeV/c)2. The data are used for the evaluation of the Ellis-Jaffe and Bjorken sum rules. The neutron spin structure function g1n(x,Q2) is small and …

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Operator Expansion For High-Energy Scattering, Ian Balitsky Jan 1996

Operator Expansion For High-Energy Scattering, Ian Balitsky

Physics Faculty Publications

I demonstrate that the leading logarithms for high-energy scattering can be obtained as a result of evolution of the non-local operators—straight-line ordered gauge factors—with respect to the slope of the straight line.

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Q² Evolution Of Chiral-Odd Twist-3 Distributions HL(𝓍, Q²) And E(𝓍, Q²) In Large- NC Qcd, I.I. Balitsky, V. M. Braun, K. Koike, K. Tanaka Jan 1996

Q² Evolution Of Chiral-Odd Twist-3 Distributions HL(𝓍, Q²) And E(𝓍, Q²) In Large- NC Qcd, I.I. Balitsky, V. M. Braun, K. Koike, K. Tanaka

Physics Faculty Publications

We prove that the twist-3 chiral-odd parton distributions obey simple Gribov-Lipatov-Altarelli-Parisi evolution equations in the limit Nc → ∞ and give analytic results for the corresponding anomalous dimensions. To this end we introduce an evolution equation for the corresponding three-particle twist-3 parton correlation functions and find an exact analytic solution. For large values of n (operator dimension) we are further able to collect all corrections subleading in Nc, so our final results are valid to O((1/N2c)ln(n)/n) accuracy

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Inclusive Electron Scattering From Nuclei At X≃1, J. Arrington, P. Anthony, R. G. Arnold, E. J. Beise, J. E. Belz, P. E. Bosted, H.- J. Bulten, M. S. Chapman, K. P. Coulter, F. Dietrich, R. Ent, M. Epstein, B. W. Filippone, H. Gao, R. A. Gearhart, D. F. Geesaman, J.- O. Hansen, R. J. Holt, H. E. Jackson, C. E. Jones, C. E. Keppel, E. R. Kinney, S. Kuhn, K. Lee, W. Lorenzon, A. Lung, N.C.R. Malkins, D. J. Margaziotis, R. D. Mckeown, R. G. Milner, B. Mueller, J. Napolitano, J. Nelson, T.G. O'Neill, V. Papavassiliou, G. G. Petratos, D. H. Potterveld, S. E. Rock, M. Spengos, Z. M. Szalata, L. H. Tao, K. Van Bibber, J.F.J. Van Den Brand, J. L. White, D. Winter, B. Zeidman Jan 1996

Inclusive Electron Scattering From Nuclei At X≃1, J. Arrington, P. Anthony, R. G. Arnold, E. J. Beise, J. E. Belz, P. E. Bosted, H.- J. Bulten, M. S. Chapman, K. P. Coulter, F. Dietrich, R. Ent, M. Epstein, B. W. Filippone, H. Gao, R. A. Gearhart, D. F. Geesaman, J.- O. Hansen, R. J. Holt, H. E. Jackson, C. E. Jones, C. E. Keppel, E. R. Kinney, S. Kuhn, K. Lee, W. Lorenzon, A. Lung, N.C.R. Malkins, D. J. Margaziotis, R. D. Mckeown, R. G. Milner, B. Mueller, J. Napolitano, J. Nelson, T.G. O'Neill, V. Papavassiliou, G. G. Petratos, D. H. Potterveld, S. E. Rock, M. Spengos, Z. M. Szalata, L. H. Tao, K. Van Bibber, J.F.J. Van Den Brand, J. L. White, D. Winter, B. Zeidman

Physics Faculty Publications

The inclusive A(e,e') cross section for x≃1 was measured on 2H, C, Fe, and Au for momentum transfers Q2 from 1 to 6.8 (GeV/c)2. The scaling behavior of the data was examined in the region of transition from y scaling to x scaling. Throughout this transitional region, the data exhibit ξ scaling, reminiscent of the Bloom-Gilman duality seen in free nucleon scattering.

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Synthesis And Characterization Of Boron-Containing Polymeric Materials For Neutron Shielding Applications, Michael B. Glasgow Jan 1996

Synthesis And Characterization Of Boron-Containing Polymeric Materials For Neutron Shielding Applications, Michael B. Glasgow

Dissertations, Theses, and Masters Projects

The development of boron-containing polymeric materials for neutron shielding applications was undertaken. Three types of materials were characterized for physical and thermal properties: boron powder-filled epoxy composites, carborane polyamides having boron chemically bonded into the polymer, and boron-loaded polyimide thin films. Addition of amorphous submicron boron powder did not affect significantly the thermal performance of the epoxy. The 17% boron loading produced a 26% increase in compressive failure strength and a 68% increase in the compressive modulus. 0.125 inch thick specimens containing 17% boron absorbed 92% of incident neutrons from a 5-Curie Pu/Be source compared with {dollar}<{dollar}1% for the neat epoxy. Dispersion of the boron in the epoxy was improved with the addition of larger size crystalline boron powders. Carborane polyamides containing up to 35% boron were thermally stable up to 400{dollar}\sp\circ{dollar}C in air. The polymers had hydrogen/boron ratios from 2.0 to 3.8 and were soluble in several organic solvents. Polymer solutions were processed into clear, colored thin films. Boron-filled polyamic acid solutions of a PMDA-ODA polyimide containing up to 10% boron were processed into thin films. Neutron absorption of the opaque films measured in a 5-Curie Pu/Be neutron source was linear with boron concentration and film thickness. The fraction of neutrons absorbed varied linearly with boron concentration and film thickness. The applicability of boron-containing materials to the aerospace, nuclear power and accelerator industries was investigated.

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The Projector Basis Method For Electronic Band Structure Calculations, Christopher Haas Jan 1996

The Projector Basis Method For Electronic Band Structure Calculations, Christopher Haas

Dissertations, Theses, and Masters Projects

Over the last several decades, two methods have emerged as the standard tools for the calculation of electronic band structures. These methods, the Car-Parinello plane wave method and the linear augmented plane wave method (LAPW), each have strengths and weaknesses in different regimes of physical problems. The Car-Parinello algorithm is ideal for calculations with soft pseudopotentials and large numbers of atoms. The LAPW method, on the other hand, easily handles all-electron and hard-core pseudopotential calculations with a small number of atoms. The projector basis method, presented here, is a hybrid mixed basis method which allows the calculation of moderately large …

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The Strong Force: Two Calculations Of Strong Interaction Phenomena, Richard L. Kahler Jan 1996

The Strong Force: Two Calculations Of Strong Interaction Phenomena, Richard L. Kahler

Dissertations, Theses, and Masters Projects

Because the theory of strong interactions is mathematically intractable, it is necessary to make approximations which preserve phenomenological features of the theory in order to get answers to practical questions. This thesis explores two such techniques: (1) the chiral bag model is used to investigate the nucleon-nucleon potential and (2) perturbative QCD is used to investigate the pion form factor. An extensive introduction is presented to make the thesis more understandable to a wider audience of people otherwise unfamiliar with particle physics.

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Surface Reflection Hyperthermal Neutral Stream Source, Christopher A. Nichols Jan 1996

Surface Reflection Hyperthermal Neutral Stream Source, Christopher A. Nichols

Dissertations, Theses, and Masters Projects

A novel source of hyperthermal (1-30 eV) reactive neutrals based on the surface-reflection-neutralization technique is described. This source is potentially capable of minimizing the charge-induced damage associated with plasma based semiconductor processing steps. The goal of this thesis is to investigate the issues involved in scale-up of this technology for processing of 8{dollar}\sp{lcub}\prime\prime{rcub}{dollar} diameter wafers used today in the semiconductor industry. This includes modeling the plasma ion source and trajectory simulations of the reflected neutral flux. A prototype source was constructed for experimental verification of the plasma model.;An inductively coupled plasma (ICP) source is used to provide a source of …

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Excitation Of An Atomic Electron To A Coherent Superposition Of Macroscopically Distinct States, Michael W. Noel, C. R. Stroud Jr. Jan 1996

Excitation Of An Atomic Electron To A Coherent Superposition Of Macroscopically Distinct States, Michael W. Noel, C. R. Stroud Jr.

Physics Faculty Research and Scholarship

An atomic electron is prepared in a state closely analogous to Schrödinger’s coherent superposition of “live cat” and “dead cat.” The electronic state is a coherent superposition of two spatially localized wave packets separated by approximately 0.4 mm at the opposite extremes of a Kepler orbit. State-selective ionization is used to verify that only every other atomic level is populated in the “cat state,” and a Ramsey fringe measurement is used to verify the coherence of the superposition.

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Using Symbolic Manipulation To Evaluate Feynman's Path Integral For An Interaction Of The Form F(T) X R, Min-Qi Bao, Anthony F. Starace Jan 1996

Using Symbolic Manipulation To Evaluate Feynman's Path Integral For An Interaction Of The Form F(T) X R, Min-Qi Bao, Anthony F. Starace

Anthony F. Starace Publications

Obtaining Feynman's path integral, which is a representation for the system's Green's function, is essential for many physical problems. In this paper, a symbolic algebra program is presented to evaluate analytically Feynman's path integral for an interaction of the form F(t) x r. Such an interaction governs the motion of an electron in the field of one or more lasers as well as in a static electric field.

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Novel Doubly Excited States Produced In Negative Ion Photodetachment, Anthony F. Starace Jan 1996

Novel Doubly Excited States Produced In Negative Ion Photodetachment, Anthony F. Starace

Anthony F. Starace Publications

Eigenchannel R-matrix calculations (including effects of long-range multipole interactions beyond the reaction volume) for Li– photodetachment partial cross sections from the vicinity of the Li 3s threshold to the Li 6s threshold (3.8 eV ≤ ħω ≤ 5.65 eV) are presented. Excellent agreement with recent relative total cross section measurements of U. Berzinsh et al. [Phys. Rev. Lett. 74, 4795 (1995)] in the vicinity of the Li 3s and Li 3p thresholds is found. The calculated resonance structures are analyzed in detail and compared with similar calculations for H– photodetachment above the H(n = …

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High-Frequency Fluctuations Of A Modulated, Helical Electron Beam, Mark Anthony Reynolds Jan 1996

High-Frequency Fluctuations Of A Modulated, Helical Electron Beam, Mark Anthony Reynolds

Publications

The high-frequency electromagnetic field generated by a density-modulated, helical electron beam propagating in a magnetized plasma is calculated. The magnetic fluctuations are found to exhibit spatially localized ~evanescent! resonances at harmonics of the electron-cyclotron frequency, whose width is determined by the pitch angle of the beam, and whose existence is a consequence of the helical geometry. In addition, electrostatic modes are radiated near the hybrid frequencies, and electromagnetic modes are radiated above the upper-hybrid frequency. The predicted frequency spectrum and mode structure in configuration space are in good agreement with experimental observations of discrete emission lines at the electron-cyclotron harmonics.

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Measurement Of The F2 Structure Function In Deep Inelastic E+P Scattering Using 1994 Data From The Zeus Detector At Hera, M. Derrick, D. Krakauer, S. Magill, D. Mikunas, B. Musgrave, J. R. Okrasinski, J. Repond, R. Stanek, R. L. Talaga, H. Zhang, Margarita C. K. Mattingly, F. Anselmo, P. Antonioli, G. Bari, M. Basile, L. Bellagamba, D. Boscherini, A. Bruni, G. Bruni, P. Bruni, G. Cara Romeo, G. Castellini, L. Cifarelli, F. Cindolo, A. Contin, M. Corradi, I. Gialas, P. Giusti, G. Iacobucci, G. Laurenti, G. Levi Jan 1996

Measurement Of The F2 Structure Function In Deep Inelastic E+P Scattering Using 1994 Data From The Zeus Detector At Hera, M. Derrick, D. Krakauer, S. Magill, D. Mikunas, B. Musgrave, J. R. Okrasinski, J. Repond, R. Stanek, R. L. Talaga, H. Zhang, Margarita C. K. Mattingly, F. Anselmo, P. Antonioli, G. Bari, M. Basile, L. Bellagamba, D. Boscherini, A. Bruni, G. Bruni, P. Bruni, G. Cara Romeo, G. Castellini, L. Cifarelli, F. Cindolo, A. Contin, M. Corradi, I. Gialas, P. Giusti, G. Iacobucci, G. Laurenti, G. Levi

Faculty Publications

We present measurements of the structure function F2 in e+p scattering at HERA in the range 3.5 GeV2 < Q2 < 5000 GeV2. A new reconstruction method has allowed a significant improvement in the resolution of the kinematic variables and an extension of the kinematic region covered by the experiment. At Q2 < 35 GeV2 the range in x now spans 6.3 · 10-5 < x < 0.08 providing overlap with measurements from fixed target experiments. At values of Q2 above 1000 GeV2 the x range extends to 0.5. Systematic errors below 5% have been achieved for most of the kinematic region. The structure function rises as x decreases; the rise becomes more pronounced as Q2 increases. The behaviour of the structure function data is well described by next-to-leading order perturbative QCD as implemented in the DGLAP evolution equations. © Springer-Verlag 1996.

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The Stability Of Compressible Mixing Layers In Binary Gases, F. Kozusko, D. G. Lasseigne, C. E. Grosch, T. L. Jackson Jan 1996

The Stability Of Compressible Mixing Layers In Binary Gases, F. Kozusko, D. G. Lasseigne, C. E. Grosch, T. L. Jackson

Mathematics & Statistics Faculty Publications

We present the results of a study of the inviscid two-dimensional spatial stability of a parallel compressible mixing layer in a binary gas. The parameters of this study are the Mach number of the fast stream, the ratio of the velocity of the slow stream to that of the fast stream, the ratio of the temperatures, the composition of the gas in the slow stream and in the fast stream, and the frequency of the disturbance wave. The ratio of the molecular weight of the slow stream to that of the fast stream is found to be an important quantity …

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Surface Debye Temperature Measurement With Reflection High-Energy Electron Diffraction, H. E. Elsayed-Ali Jan 1996

Surface Debye Temperature Measurement With Reflection High-Energy Electron Diffraction, H. E. Elsayed-Ali

Electrical & Computer Engineering Faculty Publications

Measurement of the surface mean-square atomic vibrational amplitude, or equivalently the surface Debye temperature, with reflection high-energy electron diffraction is discussed. Low-index surfaces of lead are used as examples. Particular details are given about the temperature-dependent diffraction pattern of Pb(100) in the Debye-Waller region. The use of reflection high-energy electron diffraction for measurement of the substrate surface temperature in thin-film deposition chambers is suggested. © 1996 American Institute of Physics.

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Residential Radon-222 Exposure And Lung Cancer: Exposure Assessment Methodology, R. William Field, Daniel J. Steck, Charles F. Lynch, Christine P. Brus, John S. Neuberger, Burton C. Kross Jan 1996

Residential Radon-222 Exposure And Lung Cancer: Exposure Assessment Methodology, R. William Field, Daniel J. Steck, Charles F. Lynch, Christine P. Brus, John S. Neuberger, Burton C. Kross

Physics Faculty Publications

Although occupational epidemiological studies and animal experimentation provide strong evidence that radon-222 (222Rn) progeny exposure causes lung cancer, residential epidemiological studies have not confirmed this association. Past residential epidemiological studies have yielded contradictory findings. Exposure misclassification has seriously compromised the ability of these studies to detect whether an association exists between 222Rn exposure and lung cancer. Misclassification of 222Rn exposure has arisen primarily from: 1) detector measurement error; 2) failure to consider temporal and spatial 222Rn variations within a home; 3) missing data from previously occupied homes that currently are inaccessible; 4) failure to link …

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Model Equations From Gyrokinetic Theory For A Non-Neutral Plasma To Include Temperature Effects And Applications To A Plasma Of Infinite Length, S. Neil Rasband Jan 1996

Model Equations From Gyrokinetic Theory For A Non-Neutral Plasma To Include Temperature Effects And Applications To A Plasma Of Infinite Length, S. Neil Rasband

Faculty Publications

Gyrokinetic equations are derived for applications to non-neutral plasmas in constant, straight magnetic fields wherein E X B drift velocities are of the same order as thermal velocities. The ratio of the E X B rotation frequency to the cyclotron frequency and the ratio of the gyroradius to a plasma scale length are assumed to be of order epsilon and terms are retained in the gyrokinetic expansion to second order to include finite-Larmor-radius (FLR) effects. A mode equation is obtained for a non-neutral plasma in the infinite-length approximation. The singularities of this equation are compared and contrasted with the familiar …

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Polymers Interacting With Spherical And Rodlike Particles, E. Eisenriegler, Andreas Hanke, S. Dietrich Jan 1996

Polymers Interacting With Spherical And Rodlike Particles, E. Eisenriegler, Andreas Hanke, S. Dietrich

Physics and Astronomy Faculty Publications and Presentations

The interaction of a long flexible polymer chain with mesoscopic particles of spherical or elongated cylindrical shape is investigated by field-theoretic methods using the polymer-magnet analogy. In the case that these particles are immersed in a dilute polymer solution and exhibit purely repulsive surfaces we study density profiles for monomers and chain ends near such a particle, the change of configurational entropy by immersing a particle into the solution, and the depletion interaction between a particle and a distant planar wall. Both ideal chains and chains with an excluded-volume interaction are considered. We also analyze particle surfaces with a short-ranged …

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Hierarchical Search Strategy For The Detection Of Gravitational Waves From Coalescing Binaries, Soumya Mohanty, S. Dhurandhar Jan 1996

Hierarchical Search Strategy For The Detection Of Gravitational Waves From Coalescing Binaries, Soumya Mohanty, S. Dhurandhar

Physics and Astronomy Faculty Publications and Presentations

The detection of gravitational waves from coalescing compact binaries would be a computationally intensive process if a single bank of template wave forms (i.e., a one-step search) is used. We present, in this paper, a method which leads to a large reduction in the computational power required as compared to a one-step search. This method is a hierarchical search strategy involving two template banks. We show that the computational power required by such a two-step search, for an on-line detection of the one-parameter family of Newtonian signals, is 18 of that required when an on-line one-step search is used. This …

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Measuring Strangeness Production From Relativisitic Collisions Between Pairs Of Nuclei Using A Vertex Time Projection Chamber, Christine A. Byrd, Wilfred J. Braithwaite Jan 1996

Measuring Strangeness Production From Relativisitic Collisions Between Pairs Of Nuclei Using A Vertex Time Projection Chamber, Christine A. Byrd, Wilfred J. Braithwaite

Journal of the Arkansas Academy of Science

At collider energies of 200A-GeV, tracking of charged particle pairs originating from neutrals is dominated by singlystrange KJ.' decays. Counting the number ofsecondary vertex pairs is a method of measuring the strangeness production. The VTX is a four-layer micro-strip gas time projection chamber being designed for use with the STAR instrument in an experiment using the Relativistic Heavy Ion Collider under construction at Brookhaven National Laboratory. Simulated pixel data generated from CERN's Monte Carlo detector-modeling program Geant were put into tables using the TAS sorting structures available from the STAR Collaboration. The response of VTX was mapped for charged pion …

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Wave Profile For Proforce Current Bearing Waves, Mostafa Hemmati, Steven Young Jan 1996

Wave Profile For Proforce Current Bearing Waves, Mostafa Hemmati, Steven Young

Journal of the Arkansas Academy of Science

A complete wave profile for proforce style of breakdown waves with a current behind the shock front is discussed. The solution of the electron fluid dynamical equations in the sheath region for proforce current bearing waves conforms with the expected conditins for the values of the dynamical variables at the trailing edge of the wave. The wave profile for electric field and electron velocity, temperature, and number density are presented.

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A Pathsearch Damped Newton Method For Computing General Equilibria, Steven P. Dirkse, Michael C. Ferris Jan 1996

A Pathsearch Damped Newton Method For Computing General Equilibria, Steven P. Dirkse, Michael C. Ferris

University Faculty Publications and Creative Works

Computable general equilibrium models and other types of variational inequalities play a key role in computational economics. This paper describes the design and implementation of a pathsearch damped Newton method for solving such problems. Our algorithm improves on the typical Newton method (which generates and solves a sequence of LCPs) in both speed and robustness. The underlying complementarity problem is reformulated as a normal map so that standard algorithmic enhancements of Newton's method for solving nonlinear equations can be easily applied. The solver is implemented as a GAMS subsystem, using an interface library developed for this purpose. Computational results obtained …

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Modelling An Optical Fiber Bragg Grating, Claudio Oliveira Egalon Jan 1996

Modelling An Optical Fiber Bragg Grating, Claudio Oliveira Egalon

Electrical & Computer Engineering Theses & Dissertations

A theoretical investigation of a single mode optical fiber with one and two superimposed Bragg grating is presented. The formulation relies in the determination of an approximate solution in the asymptotic region of one of the fiber parameters. A correction is then applied to the asymptotic solution using the Method of the Successive Approximations also known as the Piccard Method. The approximation was then compared to the numerical solution using the Runge-Kutta method. Assuming that each Bragg grating has modulation frequencies given by Ω1 and Ω2, it has been found that the second Bragg grating shifts the …

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Measurement Of Elastic Ω Photoproduction At Hera, M. Derrick, D. Krakauer, S. Magill, D. Mikunas, B. Musgrave, J. R. Okrasiński, J. Repond, R. Stanek, R. L. Talaga, H. Zhang, Margarita C. K. Mattingly, F. Anselmo, P. Antonioli, G. Bari, M. Basile, L. Bellagamba, D. Boscherini, A. Bruni, G. Bruni, P. Bruni, G. Cara Romeo, G. Castellini, L. Cifarelli, F. Cindolo, A. Contin, M. Corradi, I. Gialas, P. Giusti, G. Iacobucci, G. Laurenti, G. Levi Jan 1996

Measurement Of Elastic Ω Photoproduction At Hera, M. Derrick, D. Krakauer, S. Magill, D. Mikunas, B. Musgrave, J. R. Okrasiński, J. Repond, R. Stanek, R. L. Talaga, H. Zhang, Margarita C. K. Mattingly, F. Anselmo, P. Antonioli, G. Bari, M. Basile, L. Bellagamba, D. Boscherini, A. Bruni, G. Bruni, P. Bruni, G. Cara Romeo, G. Castellini, L. Cifarelli, F. Cindolo, A. Contin, M. Corradi, I. Gialas, P. Giusti, G. Iacobucci, G. Laurenti, G. Levi

Faculty Publications

No abstract provided.

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Doubly Differential Final-State Momentum Distributions Of The Ionization Products In Collision Of Bare Ions With Hydrogen, Lokesh C. Tribedi, P. Richard, Y. D. Wang, C. D. Lin, Ronald E. Olson Jan 1996

Doubly Differential Final-State Momentum Distributions Of The Ionization Products In Collision Of Bare Ions With Hydrogen, Lokesh C. Tribedi, P. Richard, Y. D. Wang, C. D. Lin, Ronald E. Olson

Physics Faculty Research & Creative Works

In this paper recoil-ion production cross sections are presented differential in recoil-ion longitudinal momentum and electron emission angle in ionization of atomic and molecular hydrogen by bare ion projectiles. A new formulation for constructing these double differential distributions from the measured electron double differential cross sections is used. A novel feature is the separation of two different branches of the recoil-ion longitudinal momentum distribution corresponding to soft and hard collision mechanisms of ionization. The single differential distributions have also been derived. © 1996 The American Physical Society.

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Imaging Of Saddle Point Electron Emission In Slow, R. Dörner, H. Khemliche, M. H. Prior, C. L. Cocke, J. A. Gary, Ronald E. Olson, V. Mergel, J. Ullrich, H. Schmidt-Böcking Jan 1996

Imaging Of Saddle Point Electron Emission In Slow, R. Dörner, H. Khemliche, M. H. Prior, C. L. Cocke, J. A. Gary, Ronald E. Olson, V. Mergel, J. Ullrich, H. Schmidt-Böcking

Physics Faculty Research & Creative Works

The two-dimensional velocity distribution of electrons emitted in 5-15 keV p - He collisions has been measured for completely determined motion of the nuclei, that is, as a function of the impact parameter and in a well defined scattering plane. The electrons are emitted preferentially in the scattering plane and in the forward direction. The velocity distributions show sharp structures that vary strongly with impact parameter and projectile velocity. The results are compared to classical trajectory calculations. © 1996 The American Physical Society.

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