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Brittle and Ductile Behavior in Carbon Nanotubes

Description: Article discussing research on the response of carbon nanotubes to a tensile load.
Date: November 23, 1998
Creator: Buongiorno Nardelli, Marco; Yakobson, Boris I. & Bernholc, Jerry
Partner: UNT College of Arts and Sciences
open access

Quantum Irreversibility and Chaos [Phys. Rev. Lett. 67, 2593 (1991)]

Description: Corrections to an equation printed with a typographical error in Quantum Irreversibility and Chaos, Physical Review Letters 67, 2593 (1991).
Date: December 23, 1991
Creator: Bonci, Luca; Roncaglia, Roberto; West, Bruce J. & Grigolini, Paolo
Partner: UNT College of Arts and Sciences
open access

Partitioning between sediment and porewater of radiocesium from Chernobyl fallout

Description: As part of a joint USA/USSR Environmental Agreement to determine the distribution and concentration of Chernobyl radioactivity in the northwest Black Sea area, the sediment from eight stations was collected and analyzed to assess the ability of sediment from the northwest Black Sea to adsorb radiocesium. Two methods were used to determine partitioning between liquid and solid phases; batch tests and porewater separation. In the batch test, Cs-137 tracer was added to mixtures of sediment and bot… more
Date: April 23, 1991
Creator: Fuhrmann, M.; Pietrzak, R. (Brookhaven National Lab., Upton, NY (USA)); Neiheisel, J. & Dyer, R. (Environmental Protection Agency, Washington, DC (USA))
Partner: UNT Libraries Government Documents Department
open access

The AGS Booster high frequency rf system

Description: A high level rf system, including a power amplifier and cavity, has been designed and built for the AGS Booster. It covers a frequency range of 2.4 to 4.2 MHz and will be used to accelerate high intensity protons. Low intensity polarized protons and heavy ions, to the 1.5 GeV level. A total accelerating voltage of up to 90 kV will be provided by two cavities, each having two gaps. The internally cross coupled, pushpull cavities are driven by an adjacently located power amplifier. In order to ac… more
Date: April 23, 1991
Creator: Sanders, R.T.; Cameron, P.; Eng, W.; Goldman, M.A.; Jablonski, E.; Kasha, D. et al.
Partner: UNT Libraries Government Documents Department
open access

Overview of spin physics

Description: Spin physics activities at medium and high energies became significantly active when polarized targets and polarized beams became accessible for hadron-hadron scattering experiments. My overview of spin physics will be inclined to the study of strong interaction using facilities at Argonne ZGS, Brookhaven AGS (including RHIC), CERN, Fermilab, LAMPF, an SATURNE. In 1960 accelerator physicists had already been convinced that the ZGS could be unique in accelerating a polarized beam; polarized beam… more
Date: December 23, 1992
Creator: Yokosawa, A.
Partner: UNT Libraries Government Documents Department
open access

Improvement of Azimuthal Homogeneity in Permanent-Magnet Bearing Rotors

Description: Permanent magnets that are levitated and rotating over a bulk high-temperature superconductor (HTS) form the basis of many superconducting bearing designs. Experiments have shown that the rotational-loss coefficient of friction'' for thrust bearings of this type can be as low as 8 [times] 10[sup [minus]6]. While the loss mechanisms of such bearings are not well understood, the azimuthal homogeneity of the rotating permanent magnet is believed to play an important role in determining the loss. O… more
Date: October 23, 1992
Creator: Hull, J. R.; Rossing, T. D.; Mulcahy, T. M. & Uherka, K. L.
Partner: UNT Libraries Government Documents Department
open access

Influence of doping on the electronic structure of (La, Sr){sub 2}CuO{sub 4}

Description: High statistics, (> 4 x 10{sup 8} counts), room temperature measurements of the electron-positron momentum density of La{sub 2-x}Sr{sub x}CuO{sub 4} have been performed for samples with Sr concentrations of x - 0.0, 0.1, 0.13 and 0.2. These spectra have been analyzed in conjunction with theoretical calculations of the electron-positron momentum density. The metallic samples show features consistent with the presence of a Fermi surface, but its evolution with increasing Sr concentration does not… more
Date: August 23, 1993
Creator: Howell, R. H.; Fluss, M. J.; Sterne, P. A.; Kaiser, J. H.; Kitazawa, K. & Kojima, H.
Partner: UNT Libraries Government Documents Department
open access

Improvement of Azimuthal Homogeneity in Permanent-Magnet Bearing Rotors

Description: Permanent magnets that are levitated and rotating over a bulk high-temperature superconductor (HTS) form the basis of many superconducting bearing designs. Experiments have shown that the rotational-loss``coefficient of friction`` for thrust bearings of this type can be as low as 8 {times} 10{sup {minus}6}. While the loss mechanisms of such bearings are not well understood, the azimuthal homogeneity of the rotating permanent magnet is believed to play an important role in determining the loss. … more
Date: October 23, 1992
Creator: Hull, J. R.; Rossing, T. D.; Mulcahy, T. M. & Uherka, K. L.
Partner: UNT Libraries Government Documents Department
open access

Ultra-shallow box-like profiles fabricated by pulsed UV-laser doping process

Description: Ultra-shallow, box-like impurity profiles are produced using Gas Immersion Laser Doping (GILD) and then analyzed by spreading resistance profilometry (SRP) and secondary ion mass spectrometry (SIMS) to determine the impurity distribution. At high concentrations, the profiles obtained by SRP exhibit the expected box-like shape over the entire range of junction depths: The measured concentration within the junction region is uniform while the dopant gradient at the junction exceeds 0.5 decades/nm… more
Date: March 23, 1993
Creator: Ishida, E.; Sigmon, T. W. & Weiner, K. H.
Partner: UNT Libraries Government Documents Department
open access

Robotics for waste storage inspection: A user`s perspective

Description: Self-navigating robotic vehicles are now commercially available, and the technology supporting other important system components has also matured. Higher reliability and the obtainability of system support now make it practical to consider robotics as a way of addressing the growing operational requirement for the periodic inspection and maintenance of radioactive, hazardous, and mixed waste inventories. This paper describes preparations for the first field deployment of an autonomous container… more
Date: June 23, 1994
Creator: Hazen, F. B.
Partner: UNT Libraries Government Documents Department
open access

High Performance Fortran: An overview

Description: The purpose of this paper is to give an overview of the work of the High Performance Fortran Forum (HPFF). This group of industry, academic, and user representatives has been meeting to define a set of extensions for Fortran dedicated to the special problems posed by a very high performance computers, especially the new generation of parallel computers. The paper describes the HPFF effort and its goals and gives a brief description of the functionality of High Performance Fortran (HPF).
Date: December 23, 1992
Creator: Zosel, M. E.
Partner: UNT Libraries Government Documents Department
open access

Envelope model of beam transport in ILSE

Description: CIRCE is an efficient beam dynamics code developed to facilitate the design and analysis of heavy-ion accelerators. The code combines an envelope description of the beam transverse dynamics with a fluid-like treatment of longitudinal dynamics, and terms are included to account for the effects of space charge, emittance, and image forces. CIRCE is currently being adapted to model the Induction Linac Systems Experiments (ILSE) facility, a proposed heavy-ion accelerator designed to test aspects of… more
Date: March 23, 1993
Creator: Sharp, W. M.; Barnard, J. J.; Grote, D. P.; Lund, S. M. & Yu, S. S.
Partner: UNT Libraries Government Documents Department
open access

Two-phase flow modeling with discrete particles

Description: The design of efficient heat exchangers in which the working fluid changes phase requires accurate modeling of two-phase fluid flow. The local Navier-Stokes equations form the basic continuum equations for this flow situation. However, the local instantaneous model using these equations is intractable for afl but the simplest problems. AH the practical models for two-phase flow analysis are based on equations that have been averaged over control volumes. These models average out the detailed de… more
Date: March 23, 1992
Creator: Mortensen, G. A. & Trapp, J. A.
Partner: UNT Libraries Government Documents Department
open access

A 1200 element detector system for synchrotron-based coronary angiography

Description: A 1200 channel Si(Li) detector system has been developed for transvenous coronary angiography experiments using synchrotron radiation. It is part of the synchrotron medical imaging facility at the National Synchrotron Light Source. The detector is made from a single crystal of lithium-drifted silicon with an active area 150 mm long {times} 11 mm high {times} 5 mm thick. The elements are arranged in two parallel rows of 600 elements with a center-to-center spacing of 0.25 mm. All 1200 elements a… more
Date: August 23, 1993
Creator: Thompson, A. C.; Lavender, W. M.; Rubenstein, E.; Giacomini, J. C.; Rosso, V.; Schulze, C. et al.
Partner: UNT Libraries Government Documents Department
open access

Rapidity distributions of K{sub s} and {Lambda}`s produced by 14.6 GeV/c Si beams on Si and Pb targets

Description: Excess strangeness production is an expected signal for formation of a Quark-Gluon Plasma and therefore we have been searching for it. We present the first measurements at AGS energies of rapidity distributions of K{sub s} and {Lambda} production with silicon beams on Silicon and Lead targets. The measurements cover the lab rapidity region of 2.0 < y < 3.5 for K{sub s} and 1.4 < y< 3.2 for {Lambda}`s. the gross features of our observation are explainable with a nuclear cascade model including N… more
Date: June 23, 1992
Creator: Lindenbaum, S. J. & Collaboration, E-810
Partner: UNT Libraries Government Documents Department
open access

DSP accelerator for the wavelet compression/decompression of high- resolution images

Description: A Texas Instruments (TI) TMS320C30-based S-Bus digital signal processing (DSP) module was used to accelerate a wavelet-based compression and decompression algorithm applied to high-resolution fingerprint images. The law enforcement community, together with the National Institute of Standards and Technology (NISI), is adopting a standard based on the wavelet transform for the compression, transmission, and decompression of scanned fingerprint images. A two-dimensional wavelet transform of the in… more
Date: July 23, 1993
Creator: Hunt, M. A.; Gleason, S. S. & Jatko, W. B.
Partner: UNT Libraries Government Documents Department
open access

Rapidity distributions of K sub s and. Lambda. 's produced by 14. 6 GeV/c Si beams on Si and Pb targets

Description: Excess strangeness production is an expected signal for formation of a Quark-Gluon Plasma and therefore we have been searching for it. We present the first measurements at AGS energies of rapidity distributions of K{sub s} and {Lambda} production with silicon beams on Silicon and Lead targets. The measurements cover the lab rapidity region of 2.0 < y < 3.5 for K{sub s} and 1.4 < y< 3.2 for {Lambda}'s. the gross features of our observation are explainable with a nuclear cascade model including N… more
Date: June 23, 1992
Creator: Lindenbaum, S. J.
Partner: UNT Libraries Government Documents Department
open access

Superconducting solenoids for the Muon collider

Description: The muon collider is a new idea for lepton colliders. The ultimate energy of an electron ring is limited by synchrotron radiation. Mouns, which have a rest mass that is 200 times that of an electron can be stored at much higher energies before synchrotron radiation limits ring performance. The problem with muon is their short lifetime (2.1 microseconds at rest). In order to operate a muon storage ring large numbers of muon must be collected, cooled and accelerated before they decay to an electr… more
Date: September 23, 1999
Creator: Green, M. A.; Eyssa, Y.; Kenny, S.; Miller, J. R.; Prestemon, S. & Weggel, R. J.
Partner: UNT Libraries Government Documents Department
open access

Two-phase flow modeling with discrete particles

Description: The design of efficient heat exchangers in which the working fluid changes phase requires accurate modeling of two-phase fluid flow. The local Navier-Stokes equations form the basic continuum equations for this flow situation. However, the local instantaneous model using these equations is intractable for afl but the simplest problems. AH the practical models for two-phase flow analysis are based on equations that have been averaged over control volumes. These models average out the detailed de… more
Date: March 23, 1992
Creator: Mortensen, G. A. & Trapp, J. A.
Partner: UNT Libraries Government Documents Department
open access

Application of x-rays lasers as imaging and plasma diagnostics

Description: This report describes utilization of multilayer mirrors and beam splitters to develop x-ray laser interferometry, radiography, and deflectometry to probe high-density laser plasmas.
Date: March 23, 1994
Creator: Wan, A. S.; Da Silva, L. B. & Barbee, T. W.
Partner: UNT Libraries Government Documents Department
open access

A high-power switch-mode dc power supply for dynamic loads

Description: High-voltage dc power supplies are often required to operate with highly dynamic loads, such as arcs. A switch-mode dc power supply can offer significant advantages over conventional thyristor-based dc power supplies under such conditions. It can quickly turn off the supply to extinguish the arc, and it can quickly recover after the arc. It has a relatively small output filter capacitance, which results in small stored energy available to the arc. A 400-kW, 50-kV switch-mode dc power supply for… more
Date: June 23, 1994
Creator: Shimer, D. W.; Lange, A. C. & Bombay, J. N.
Partner: UNT Libraries Government Documents Department
open access

Current status of the recirculator project at LLNL

Description: The Heavy Ion Fusion Group at Lawrence Livermore National Laboratory has for several years been developing the world's first circular ion induction accelerator designed to transport space charge dominated beams. Currently, the machine extends to 90 degrees, or 10 half-lattice periods (HLP) with induction cores for acceleration placed on every other HLP. Full current transport with acceptable emittance growth without acceleration has been achieved. Recently, a time stability measurement revealed… more
Date: March 23, 1999
Creator: Ahle, L; Autrey, D; Barnard, J; Craig, G; Debeling, A; Eylon, S et al.
Partner: UNT Libraries Government Documents Department
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