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Inhibition of K+ currents of outer hair cells in guinea pig cochlea by fluoxetine (open access)

Inhibition of K+ currents of outer hair cells in guinea pig cochlea by fluoxetine

Article discussing the inhibition of K+ currents of outer hair cells in guinea pig cochlea by fluoxetine.
Date: October 25, 2002
Creator: Bian, Jing-Tan; Yeh, Jay Z.; Aistrup, Gary L.; Narahashi, Toshio & Moore, Ernest J.
System: The UNT Digital Library
Peter Schneider's "Eduards Heimkehr" and the Image of the "New Berlin" (open access)

Peter Schneider's "Eduards Heimkehr" and the Image of the "New Berlin"

Article discussing Peter Schneider's "Eduards Heimkehr" and the image of the "New Berlin."
Date: October 2002
Creator: Costabile-Heming, Carol Anne
System: The UNT Digital Library
High pT inclusive charged hadron spectra from Au+Au collisions at {radical}(s{sub NN}) = 200 Gev (open access)

High pT inclusive charged hadron spectra from Au+Au collisions at {radical}(s{sub NN}) = 200 Gev

The STAR Collaboration presents new measurements of inclusive charged hadron distributions for p{sub T} < 12 GeV/c from Au+Au collisions at {radical}(s{sub NN}) = 200GeV. Charged hadron suppression at high p{sub T} is similar in shape and magnitude at all centralities to that observed previously at {radical}(s{sub NN}) = 130 GeV for p{sub T} < 6 GeV/c. The ratio of spectra from central and peripheral Au+Au collisions shows that hadron suppression is approximately constant within 6 < p{sub T} < 12 GeV/c. The ratios of charged hadron spectra at the two beam energies show a 15-20 percent increase in yield at low p{sub T}. At high p{sub T}, the ratios show a larger increase that agrees well with pQCD calculations of the {radical}(s{sub NN}) dependence of particle production in Au+Au collisions.
Date: October 17, 2002
Creator: Klay, Jennifer L.
System: The UNT Digital Library
Magnetism in heterogeneous thin film systems: Resonant x-ray scattering studies (open access)

Magnetism in heterogeneous thin film systems: Resonant x-ray scattering studies

Magnetic and chemical heterogeneity are common in a broad range of magnetic thin film systems. Emerging resonant soft x-ray scattering techniques are well suited to resolve such heterogeneity at relevant length scales. Resonant x-ray magneto-optical Kerr effect measurements laterally average over heterogeneity but can provide depth resolution in different ways, as illustrated in measurements resolving reversible and irreversible changes in different layers of exchange-spring heterostructures. Resonant small-angle scattering measures in-plane heterogeneity and can resolve magnetic and chemical scattering sources in different ways, as illustrated in measurements of granular alloy recording media.
Date: October 28, 2002
Creator: Kortright, J. B.; Jiang, J. S.; Bader, S. D.; Hellwig, O.; Marguiles, D. T. & Fullerton, E. E.
System: The UNT Digital Library
Physics Prospects with the JLab 12-GeV upgrade (open access)

Physics Prospects with the JLab 12-GeV upgrade

Increasing the beam energy of the CEBAF accelerator to 12 GeV will greatly expand the physics opportunities to explore the nature of strongly interacting matter. The primary thrusts of the experimental program will include the study of quark confinement and the direct exploration of the quark-gluon structure of hadrons and nuclei in the valence-quark region.
Date: October 1, 2002
Creator: Smith, Elton
System: The UNT Digital Library
Review of North American Neutrino Factory R and D (open access)

Review of North American Neutrino Factory R and D

We report here on the R and D program of the U.S. Neutrino Factory and Muon Collider Collaboration. Our effort includes work on targetry, muon ionization cooling, simulation work, and development of superconducting RF cavities. In addition, we are involved in the international effort toward a Muon Ionization Cooling Experiment (MICE). Recent activities in all these areas will be described.
Date: October 7, 2002
Creator: Zisman, Michael S. & Collaboration, Neutrino Factory and Muon Collider
System: The UNT Digital Library
Recent Developments on the 110 GHz Electron Cyclotron Instatllation on the DIII-D Tokamak (open access)

Recent Developments on the 110 GHz Electron Cyclotron Instatllation on the DIII-D Tokamak

OAK A271 RECENT DEVELOPMENTS ON THE 110 GHZ ELECTRON CYCLOTRON INSTALLATION ON THE DIII-D TOKAMAK. Significant improvements are being implement4ed to the capability of the 110 GHz electron cyclotron system on the DIII-D tokamak. Chief among these is the addition of the fifth and sixth 1 MW class gyrotrons, increasing the power available for auxiliary heating and current drive by nearly 60%. These tubes use artificially grown diamond rf output windows to obtain high power with long pulse capability. The beams from these tubes are nearly Gaussian, facilitating coupling to the waveguide. A new fully articulating dual launcher capable of high speed spatial scanning has been designed and tested. The launcher has two axis independent steering for each waveguide. the mirrors can be rotated at up to 100{sup o}/s. A new feedback system linking the DIII-D Plasma Control System (PCS) with the gyrotron beam voltage waveform generators permits real-time feedback control of some plasma properties such as electron temperature. The PCS can use a variety of plasma monitors to generate its control signal, including electron cyclotron emission and Mirnov probes. Electron cyclotron heating and electron cyclotron current drive (ECH and ECCD) were used during this year's DIII-D experimental campaign to …
Date: October 1, 2002
Creator: Ponce, D.; Callis, R. W.; Cary, W. P.; Ferron, J. R.; Green, M.; Grunloh, H. J. et al.
System: The UNT Digital Library
Disruption Mitigation With High-Pressure Noble Gas Injection (open access)

Disruption Mitigation With High-Pressure Noble Gas Injection

OAK A271 DISRUPTION MITIGATION WITH HIGH-PRESSURE NOBLE GAS INJECTION. High-pressure gas jets of neon and argon are used to mitigate the three principal damaging effects of tokamak disruptions: thermal loading of the divertor surfaces, vessel stress from poloidal halo currents and the buildup and loss of relativistic electrons to the wall. The gas jet penetrates as a neutral species through to the central plasma at its sonic velocity. The injected gas atoms increase up to 500 times the total electron inventory in the plasma volume, resulting in a relatively benign radiative dissipation of >95% of the plasma stored energy. The rapid cooling and the slow movement of the plasma to the wall reduce poloidal halo currents during the current decay. The thermally collapsed plasma is very cold ({approx} 1-2 eV) and the impurity charge distribution can include > 50% fraction neutral species. If a sufficient quantity of gas is injected, the neutrals inhibit runaway electrons. A physical model of radiative cooling is developed and validated against DIII-D experiments. The model shows that gas jet mitigation, including runaway suppression, extrapolates favorably to burning plasmas where disruption damage will be more severe. Initial results of real-time disruption detection triggering gas jet injection …
Date: October 2002
Creator: Whyte, D. G.; Jernigan, T. C.; Humphreys, D. A.; Hyatt, A. W.; Lasnier, C. J.; Parks, P. B. et al.
System: The UNT Digital Library
Simulation of chamber transport for heavy-ion fusion (open access)

Simulation of chamber transport for heavy-ion fusion

Beams for heavy-ion fusion (HIF) are expected to require substantial neutralization in a target chamber. Present targets call for higher beam currents and smaller focal spots than most earlier designs, leading to high space-charge fields. Collisional stripping by the background gas expected in the chamber further increases the beam charge. Simulations with no electron sources other than beam stripping and background-gas ionization show an acceptable focal spot only for high ion energies or for currents far below the values assumed in recent HIF power-plant scenarios. Much recent research has, therefore, focused on beam neutralization by electron sources that were neglected in earlier simulations, including emission from walls and the target, photoionization by radiation from the target, and pre-neutralization by a plasma generated along the beam path. The simulations summarized here indicate that these effects can significantly reduce the beam focal-spot size.
Date: October 4, 2002
Creator: Sharp, W. M.; Callahan, D. A.; Tabak, M. A.; Yu, S. S.; Peterson, P. F.; Rose, D. V. et al.
System: The UNT Digital Library
Pressure and fluid saturation prediction in a multicomponent reservoir, using combined seismic and electromagnetic imaging (open access)

Pressure and fluid saturation prediction in a multicomponent reservoir, using combined seismic and electromagnetic imaging

This paper presents a method for combining seismic and electromagnetic measurements to predict changes in water saturation, pressure, and CO{sub 2} gas/oil ratio in a reservoir undergoing CO{sub 2} flood. Crosswell seismic and electromagnetic data sets taken before and during CO{sub 2} flooding of an oil reservoir are inverted to produce crosswell images of the change in compressional velocity, shear velocity, and electrical conductivity during a CO{sub 2} injection pilot study. A rock properties model is developed using measured log porosity, fluid saturations, pressure, temperature, bulk density, sonic velocity, and electrical conductivity. The parameters of the rock properties model are found by an L1-norm simplex minimization of predicted and observed differences in compressional velocity and density. A separate minimization, using Archie's law, provides parameters for modeling the relations between water saturation, porosity, and the electrical conductivity. The rock-properties model is used to generate relationships between changes in geophysical parameters and changes in reservoir parameters. Electrical conductivity changes are directly mapped to changes in water saturation; estimated changes in water saturation are used along with the observed changes in shear wave velocity to predict changes in reservoir pressure. The estimation of the spatial extent and amount of CO{sub 2} relies on …
Date: 2002-10~
Creator: Hoversten, G. M.; Gritto, Roland; Washbourne, John & Daley, Tom
System: The UNT Digital Library
Search for CP violation in hyperon decays. (open access)

Search for CP violation in hyperon decays.

Direct CP violation in nonleptonic hyperon decays can be established by comparing the decays of hyperons and anti-hyperons. For {Xi} decay to {Lambda} {pi} followed by {Lambda} to p{pi}, the proton distribution in the rest frame of Lambda is governed by the product of the decay parameters {alpha}{sub {Xi}} {alpha}{sub {Lambda}}. The asymmetry A{sub {Xi}{Lambda}}, proportional to the difference of {alpha}{sub {Xi}}{alpha}{sub {Lambda}} of the hyperon and anti-hyperon decays, vanishes if CP is conserved. We report on an analysis of a fraction of 1997 and 1999 data collected by the Hyper CP (E871) collaboration during the fixed-target runs at Fermilab. The preliminary measurement of the asymmetry is {Alpha}{sub {Xi}{Lambda}} = [-7 {+-} 12(stat) {+-} 6.2(sys)] x 10{sup -4}, an order of magnitude better than the present limit.
Date: October 25, 2002
Creator: Zyla, Piotr
System: The UNT Digital Library
ROLE OF NEUTRALS IN CORE FUELING AND PEDESTAL STRUCTURE IN H-MODE DIII-D DISCHARGES (open access)

ROLE OF NEUTRALS IN CORE FUELING AND PEDESTAL STRUCTURE IN H-MODE DIII-D DISCHARGES

OAK A271 ROLE OF NEUTRALS IN CORE FUELING AND PEDESTAL STRUCTURE IN H-MODE DIII-D DISCHARGES. The 2-D fluid code UEDGE was used to analyze DIII-D experiments to determine the role of neutrals in core fueling, core impurities, and also the H-mode pedestal structure. The authors compared the effects of divertor closure on the fueling rate and impurity density of high-triangularity, H-mode plasmas. UEDGE simulations indicate that the decrease in both deuterium core fueling ({approx} 15%-20%) and core carbon density ({approx} 15%-30%) with the closed divertor compared to the open divertor configuration is due to greater divertor screening of neutrals. They also compared UEDGE results with a simple analytic model of the H-mode pedestal structure. The model predicts both the width and gradient of the transport barrier in n{sub e} as a function of the pedestal density. The more sophisticated UEDGE simulations of H-mode discharges corroborate the simple analytic model, which is consistent with the hypothesis that fueling processes play a role in H-mode transport barrier formation.
Date: October 2002
Creator: Wolf, N. S.; Petrie, T. W.; Porter, G. D.; Rognlien, T. D.; Groebner, R. J. & Makowski, M. A.
System: The UNT Digital Library
Disappearance of back-to-back high p {sub T} hadron correlations in central Au+Au collisions at {radical}s{sub NN} = 200 GeV (open access)

Disappearance of back-to-back high p {sub T} hadron correlations in central Au+Au collisions at {radical}s{sub NN} = 200 GeV

Azimuthal correlations for large transverse momentum charged hadrons have been measured over a wide pseudo-rapidity range and full azimuth in Au+Au and p+p collisions at = {radical}s{sub NN} = 200 GeV. The small-angle correlations observed in p+p collisions and at all centralities of Au+Au collisions are characteristic of hard-scattering processes already observed in elementary collisions. A strong back-to-back correlation exists for p+p and peripheral Au + Au. In contrast, the back-to-back correlations are reduced considerably in the most central Au+Au collisions, indicating substantial interaction as the hard-scattered partons or their fragmentation products traverse the medium.
Date: October 25, 2002
Creator: Adler, C.; Ahammed, Z.; Allgower, C.; Amonett, J.; Anderson, B. D.; Anderson, M. et al.
System: The UNT Digital Library
Labs21 Environmental Performance Criteria: Toward 'LEED (trademark) for Labs' (open access)

Labs21 Environmental Performance Criteria: Toward 'LEED (trademark) for Labs'

Laboratory facilities present a unique challenge for energy efficient and sustainable design, with their inherent complexity of systems, health and safety requirements, long-term flexibility and adaptability needs, energy use intensity, and environmental impacts. The typical laboratory is about three to five times as energy intensive as a typical office building and costs about three times as much per unit area. In order to help laboratory stakeholders assess the environmental performance of their laboratories, the Labs21 program, sponsored by the US Environmental Protection Agency and the US Department of Energy, is developing the Environmental Performance Criteria (EPC), a point-based rating system that builds on the LEED(TM) rating system. Currently, LEED(TM) is the primary tool used to rate the sustainability of commercial buildings. However, it lacks some attributes essential to encouraging the application of sustainable design principles to laboratory buildings. Accordingly, the EPC has additions and modifications to the prerequisites and credits in each of the six sections of LEED(TM). It is being developed in a consensus-based approach by a diverse group of architects, engineers, consulting experts, health & safety personnel and facilities personnel. This report describes the EPC version 2.0, highlighting the underlying technical issues, and describes implications for the development …
Date: October 14, 2002
Creator: Mathew, Paul; Sartor, Dale; Lintner, William & Wirdzek, Phil
System: The UNT Digital Library
Nucleon Form Factors (open access)

Nucleon Form Factors

A review of data on the nucleon electro-weak form factors in the space-like region is presented. Recent results from experiments using polarized beams and either polarized targets or nucleon recoil polarimeters have yielded a significant improvement on the precision of the electromagnetic data obtained with the traditional Rosenbluth separation. An outlook is presented of planned experiments.
Date: October 1, 2002
Creator: Jager, Kees de
System: The UNT Digital Library
NEUTRINO SUPER BEAM FACILITY FOR A LONG BASELINE EXPERIMENT FROM BNL TO HOMESTAKE. (open access)

NEUTRINO SUPER BEAM FACILITY FOR A LONG BASELINE EXPERIMENT FROM BNL TO HOMESTAKE.

An upgrade to the BNL Alternate Gradient Synchrotron (AGS) could produce a very intense proton source at a relatively low cost. Such a proton beam could be used to generate a conventional neutrino beam with a significant flux at large distances from the laboratory. This provides the possibility of a very long baseline neutrino experiment at the Homestake mine. The construction of this facility would allow a program of experiments to study many of the aspects of neutrino oscillations including CP violations. This study examines a 1 MW proton source at BNL and a large 1 megaton detector positioned at the Homestake Mine as the ultimate goal of a staged program to study neutrino oscillations.
Date: October 21, 2002
Creator: Kahn, S.
System: The UNT Digital Library
Interfacing interactive data analysis tools with the grid: The PPDG CS-11 activity (open access)

Interfacing interactive data analysis tools with the grid: The PPDG CS-11 activity

For today's physicists, who work in large geographically distributed collaborations, the data grid promises significantly greater capabilities for analysis of experimental data and production of physics results than is possible with today's ''remote access'' technologies. The goal of letting scientists at their home institutions interact with and analyze data as if they were physically present at the major laboratory that houses their detector and computer center has yet to be accomplished. The Particle Physics DataGrid project (www.ppdg.net) has recently embarked on an effort to ''Interface and Integrate Interactive Data Analysis Tools with the grid and identify Common Components and Services.'' The initial activities are to collect known and identify new requirements for grid services and analysis tools from a range of current and future experiments (ALICE, ATLAS, BaBar, D0, CMS, JLab, STAR, others welcome), to determine if existing plans for tools and services meet these requirements. Follow-on activities will foster the interaction between grid service developers, analysis tool developers, experiment analysis frame work developers and end user physicists, and will identify and carry out specific development/integration work so that interactive analysis tools utilizing grid services actually provide the capabilities that users need. This talk will summarize what we know of …
Date: October 9, 2002
Creator: Olson, Douglas L. & Perl, Joseph
System: The UNT Digital Library
Advanced Tokamak Operation Using the DIII-D Plasma Control System (open access)

Advanced Tokamak Operation Using the DIII-D Plasma Control System

A271 ADVANCED TOKAMAK OPERATION USING THE DIII-D PLASMA CONTROL SYSTEM. The principal focus of experimental operations in the DIII-D tokamak is the advanced tokamak (AT) regime to achieve, which requires highly integrated and flexible plasma control. In a high performance advanced tokamak, accurate regulation of the plasma boundary, internal profiles, pumping, fueling, and heating must be well coordinated with MHD control action to stabilize such instabilities as tearing modes and resistive wall modes. Sophisticated monitors of the operational regime must provide detection of off-normal conditions and trigger appropriate safety responses with acceptable levels of reliability. Many of these capabilities are presently implemented in the DIII-D plasma control system (PCS), and are now in frequent or routine operational use. The present work describes recent development, implementation, and operational experience with AT regime control elements for equilibrium control, MHD suppression, and off-normal event detection and response.
Date: October 1, 2002
Creator: Humphreys, D. A.; Ferron, J. R.; Garofalo, A. M.; Hyatt, A. W.; Jernigan, T. C.; Johnson, R. D. et al.
System: The UNT Digital Library
RHIC AND THE SEARCH FOR HIGH ENERGY DENSITY MATTER. (open access)

RHIC AND THE SEARCH FOR HIGH ENERGY DENSITY MATTER.

The major goal of the RHIC experimental program at Brookhaven National Laboratory is to make and study the Quark Gluon Plasma. Another new form of matter, the Color Glass Condensate may be formed in these collisions. The recent results from RHIC are reviewed in this context.
Date: October 2, 2002
Creator: McLerran, L.
System: The UNT Digital Library
Determining worst-case fatigue thresholds for grain-bridging ceramics (open access)

Determining worst-case fatigue thresholds for grain-bridging ceramics

A method for determining worst-case cyclic fatigue thresholds in grain-bridging ceramics by quantifying the role of bridging is demonstrated for a model alumina. Crack-growth properties for both long and short (< 2 mm) cracks emanating from machined notches (root radii, (rho) {approx}; 15 - 150 (mu)m) were investigated. When compared as a function of the applied stress-intensity range (delta K), growth rates (da/dN) were far higher and fatigue thresholds (Delta)KTH were markedly lower with short cracks, with growth being observable at the lowest driving forces for short cracks emanating from razor micronotches ((rho)is approximately equal to 15 (mu)m). For growth rates < 10-8 m/cycle, da/dN vs. (delta)K data for short cracks merged with the steady-state data for long cracks after {approx}2 mm of extension.
Date: October 7, 2002
Creator: Kruzic, J. J.; Yuan, R.; Canon, R. M. & Ritchie, R. O.
System: The UNT Digital Library
Predicting Indoor Pollutant Concentrations, and Applications to Air Quality Management (open access)

Predicting Indoor Pollutant Concentrations, and Applications to Air Quality Management

Because most people spend more than 90% of their time indoors, predicting exposure to airborne pollutants requires models that incorporate the effect of buildings. Buildings affect the exposure of their occupants in a number of ways, both by design (for example, filters in ventilation systems remove particles) and incidentally (for example, sorption on walls can reduce peak concentrations, but prolong exposure to semivolatile organic compounds). Furthermore, building materials and occupant activities can generate pollutants. Indoor air quality depends not only on outdoor air quality, but also on the design, maintenance, and use of the building. For example, ''sick building'' symptoms such as respiratory problems and headaches have been related to the presence of air-conditioning systems, to carpeting, to low ventilation rates, and to high occupant density (1). The physical processes of interest apply even in simple structures such as homes. Indoor air quality models simulate the processes, such as ventilation and filtration, that control pollutant concentrations in a building. Section 2 describes the modeling approach, and the important transport processes in buildings. Because advection usually dominates among the transport processes, Sections 3 and 4 describe methods for predicting airflows. The concluding section summarizes the application of these models.
Date: October 1, 2002
Creator: Lorenzetti, David M.
System: The UNT Digital Library
Aspects of Parallel Simulation of High Intensity Beams in Hadron Rings. (open access)

Aspects of Parallel Simulation of High Intensity Beams in Hadron Rings.

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Date: October 16, 2002
Creator: Luccio, A. U. & D Imperio, N. L.
System: The UNT Digital Library
Technology choices for the Integrated Beam Experiment (IBX) (open access)

Technology choices for the Integrated Beam Experiment (IBX)

Over the next three years the research program of the Heavy Ion Fusion Virtual National Laboratory (HIF-VNL), a collaboration among LBNL, LLNL, and PPPL, is focused on separate scientific experiments in the injection, transport and focusing of intense heavy ion beams at currents from 100 mA to 1 A. As a next major step in the HIF-VNL program, we aim for a complete ''source-to-target'' experiment, the Integrated Beam Experiment (IBX). By combining the experience gained in the current separate beam experiments IBX would allow the integrated scientific study of the evolution of a single heavy ion beam at high current ({approx}1 A) through all sections of a possible heavy ion fusion accelerator: the injection, acceleration, compression, and beam focusing. This paper describes the main parameters and technology choices of the planned IBX experiment. IBX will accelerate singly charged potassium or argon ion beams up to 10 MeV final energy and a longitudinal beam compression ratio of 10, resulting in a beam current at target of more than 10 Amperes. Different accelerator cell design options are described in detail: Induction cores incorporating either room temperature pulsed focusing-magnets or superconducting magnets.
Date: October 31, 2002
Creator: Leitner, M. A.; Celata, C. M.; Lee, E. P.; Sabbi, G.; Waldron, W. L. & Barnard, J. J.
System: The UNT Digital Library
DESIGN, FABRICATION, INSTALLATION AND TESTING OF IN-VESSEL CONTROL COILS FOR DIII-D (open access)

DESIGN, FABRICATION, INSTALLATION AND TESTING OF IN-VESSEL CONTROL COILS FOR DIII-D

OAK A271 DESIGN, FABRICATION, INSTALLATION AND TESTING OF IN-VESSEL CONTROL COILS FOR DIII-D. Since 1995, DIII-D has performed correction of magnetic field imperfections using a set of six external picture frame coils located on the vessel mid-plane. Recently, these coils have also demonstrated significant benefits when used for feedback of the resistive wall mode, an instability that limits the plasma performance at high beta. Modeling has shown that substantial performance improvements can be achieved by installing new coils inside the vessel and expanding the poloidal coverage above and below the mid-plane. Two prototype internal coils were installed in 2001 and have been tested successfully. installation of a set of twelve internal coils and magnetic sensors in the DIII-D tokamak is to be completed in December 2002. The design requirement for the new coil system was to maximize the magnetic field at the plasma edge, operate with a frequency range of dc to 1000 Hz, and fit behind the existing graphite wall tiles. The coil design adopted and installed is a water-cooled hollow copper conductor insulated with polyamide and housed inside a stainless steel tube that forms a vacuum boundary. The coil is rigidly mounted to the inside of the vacuum …
Date: October 1, 2002
Creator: Anderson, P. M.; Baxi, C. B.; Kellman, A. G.; Reis, E. E. & Robinson, J. I.
System: The UNT Digital Library