Multi-Tube Power Leads Tower for Bepcii Ir Magnets. (open access)

Multi-Tube Power Leads Tower for Bepcii Ir Magnets.

A power lead tower containing the multi-tube power leads is designed and under fabrication for the superconducting IR quadrupole magnets in the Beijing Electron Position Collider Upgrade (BEPCII). The lead tower consists of six pairs of gas-cooled leads for seven superconducting coils at various operating currents. The power lead is designed in a modular fashion, which can be easily applied to suit different operating current. The end copper block of the tube lead has a large cold mass that provide a large time constant in case of cooling flow interruption. A novel cryogenic electrical isolator is used for the leads.
Date: May 11, 2004
Creator: Jia, L. X.; Zhang, X. B.; Wang, L.; Wang, T. H. & Yao, Z. L.
Object Type: Article
System: The UNT Digital Library
Speckle Imaging of Titan at 2 microns: Surface Albedo, Haze Optical Depth, and Tropospheric Clouds 1996-1998 (open access)

Speckle Imaging of Titan at 2 microns: Surface Albedo, Haze Optical Depth, and Tropospheric Clouds 1996-1998

We present results from 14 nights of observations of Titan in 1996-1998 using near-infrared (centered at 2.1 microns) speckle imaging at the 10-meter W.M. Keck Telescope. The observations have a spatial resolution of 0.06 arcseconds. We detect bright clouds on three days in October 1998, with a brightness about 0.5% of the brightness of Titan. Using a 16-stream radiative transfer model (DISORT) to model the central equatorial longitude of each image, we construct a suite of surface albedo models parameterized by the optical depth of Titan's hydrocarbon haze layer. From this we conclude that Titan's equatorial surface albedo has plausible values in the range of 0-0.20. Titan's minimum haze optical depth cannot be constrained from this modeling, but an upper limit of 0.3 at this wavelength range is found. More accurate determination of Titan's surface albedo and haze optical depth, especially at higher latitudes, will require a model that fully considers the 3-dimensional nature of Titan's atmosphere.
Date: February 11, 2004
Creator: Gibbard, S. G.; Gavel, D.; Ghez, A. M.; de Pater, I.; Max, C. E.; Young, E. F. et al.
Object Type: Article
System: The UNT Digital Library
Letter to the Editors of Physics Today (open access)

Letter to the Editors of Physics Today

Two points in our recent article on Edward Teller's scientific life (Physics Today, August 2004, page 45) require correction. In our description of Teller's students, we incorrectly stated that Arthur Kantrowitz's thesis was on the generation of hypersonic molecular beams. Actually, his thesis was on heat capacity lags in gas dynamics. Kantrowitz's invention of high intensity sources for molecular beams came later in his career. Maurice Goldhaber has emphasized that the situation with respect to possible nuclear resonances in ({gamma},n) or ({gamma},fission) reactions was quite unclear at the time of George C. Baldwin and G. Stanley Klaiber's papers on these reactions. This was because the rapid rise of their yield to a prominent peak with increasing energy, followed by a slower fall off was then thought to have been due to the competition between the rapidly rising density of nuclear states and the eventual domination of other reaction channels at higher energies. Goldhaber realized, however, that there could be an analogy between a possible collective nuclear resonance and the restrahl resonance (essentially the transverse optical phonon mode) in polar crystals. Goldhaber sought out Teller because of his paper with Russell Lyddane and Robert Sachs, relating the restrahl frequency to the …
Date: November 11, 2004
Creator: Libby, S B & Weiss, M S
Object Type: Article
System: The UNT Digital Library
Example Programs for KINSOL v2.2.0 (open access)

Example Programs for KINSOL v2.2.0

None
Date: November 11, 2004
Creator: Collier, A M & Serban, R
Object Type: Text
System: The UNT Digital Library
Thermal Fluid Modeling of Bepcii Ir Quadrupole Magnet Cryostat. (open access)

Thermal Fluid Modeling of Bepcii Ir Quadrupole Magnet Cryostat.

A pair of superconducting interaction region quadrupole magnets for BEPCII was designed and fabricated at Brookhaven National Laboratory, USA. The cryogenic system for the IR magnets was designed at Harbin Institute of Technology, China. This paper provides the results of thermal fluid modeling for the magnet cryostat. The numerical analyses were carried out for two types of cooling methods, the subcooled liquid helium and the supercritical helium flow. The pressure and temperature changes in the cooling circuits are given.
Date: May 11, 2004
Creator: Wang, L.; Tang, H. M.; Zhang, X. B.; Yang, G. D. & Jia, L. X.
Object Type: Article
System: The UNT Digital Library
Groundwater Data Package for the 2004 Composite Analysis (open access)

Groundwater Data Package for the 2004 Composite Analysis

This report presents data and information that supports the groundwater module. The conceptual model of groundwater flow and transport at the Hanford Site is described and specific information applied in the numerical implementation module is provided.
Date: August 11, 2004
Creator: Thorne, Paul D.
Object Type: Report
System: The UNT Digital Library
A Study of the Ion Hose Instability in the DARHT-II Downstream Transport Region (open access)

A Study of the Ion Hose Instability in the DARHT-II Downstream Transport Region

The second axis of the DARHT flash X-ray facility at Los Alamos National Laboratory (''DARHT-II'') is a multiple-pulse, 18.4 MeV, 2 kA induction electron linear accelerator [1]. A train of short ({approx}50 ns) pulses are converted via bremsstrahlung to X-rays, which are then used to make radiographic images at various times (nominally four) during a ''hydrotest'' experiment. The train of pulses is created by carving them out of a two microsecond long macropulse, using a fast switching element called a kicker [2]. The unused portion of the macropulse is absorbed in a beam dump. Thus, upstream of the kicker, two microseconds of beam are transported through a vacuum system roughly sixty meters long. These conditions involve length and, specifically, time scales which are new to the transport of high-current beams. A concern under such conditions are the macroscopic interactions between the electron beam and positive ions created by impact ionization of the residual gas in the vacuum system. Over two microseconds, the ion density can develop to a hundredth or even a tenth of a percent of the beam density--small, to be sure, but large enough to have cumulative effects over such a long transport distance. Two such effects will …
Date: November 11, 2004
Creator: McCarrick, J F
Object Type: Report
System: The UNT Digital Library
NotCal04 - Comparison / Calibration 14C records 26-50 cal kBP (open access)

NotCal04 - Comparison / Calibration 14C records 26-50 cal kBP

The radiocarbon calibration curve, IntCal04, extends back to 26 cal kBP. While several high resolution records exist beyond this limit, these data sets exhibit discrepancies one to another of up to several millennia. As a result, no calibration curve for the time range 26-50 cal kBP can be recommended as yet, but in this paper the IntCal04 working group compares the available data sets and offers a discussion of the information that they hold.
Date: November 11, 2004
Creator: der Plicht, J. V.; Beck, J.; Bard, E. & Baille, M.
Object Type: Article
System: The UNT Digital Library
Optical Probes For Continuous Fabry-Perot Velocimetry Inside Materials (open access)

Optical Probes For Continuous Fabry-Perot Velocimetry Inside Materials

We have used velocimetry for many years at LLNL to measure velocity-time histories of surfaces in dynamic experiments. We have developed and now use special instrumentation to make continuous shock-velocity measurements inside of materials. The goal is to extend the field of velocimetry into a new area of application in shock physics. At the last Congress we reported the successful use of our new filter system for selectively eliminating most of the non- Doppler-shifted light. We showed one record of a fiber embedded inside an explosive making a continuous detonation velocity-time history. At that time it was difficult to obtain complete records. We have now carried out over 65 inexpensive experiments usually using small cylinders or rectangular blocks of explosives or metals. Most were started by detonating a 25 mm diam by 25 mm long cylinder of Comp B explosive to drive a shock into an adjacent material of similar dimensions, using our embedded fiber probes. In contrast to surface velocimetry, embedded measurements involve detailed hydrodynamic considerations in order to result in a successful record. Calculations have guided us in understanding of various failed and successful experiments. The homogeneity of the explosive, poor contact, the materials used in the cladding …
Date: August 11, 2004
Creator: Goosman, D.; Wade, J.; Garza, R.; Avara, G.; Crabtree, T.; Rivera, A. et al.
Object Type: Article
System: The UNT Digital Library
Single-State Electronic Structure Measurements Using Time-Resolved X-Ray Laser Induced Photoelectron Spectroscopy (open access)

Single-State Electronic Structure Measurements Using Time-Resolved X-Ray Laser Induced Photoelectron Spectroscopy

We demonstrate single-shot x-ray laser induced time-of-flight photoelectron spectroscopy on semiconductor and metal surfaces with picosecond time resolution. The LLNL COMET compact tabletop x-ray laser source provides the necessary high photon flux (>10{sup 12}/pulse), monochromaticity, picosecond pulse duration, and coherence for probing ultrafast changes in the city, chemical and electronic structure of these materials. Static valence band and shallow core-level photoemission spectra are presented for ambient temperature Ge(100) and polycrystalline Cu foils. Surface contamination was removed by UV ozone cleaning prior to analysis. In addition, the ultrafast nature of this technique lends itself to true single-state measurements of shocked and heated materials. Time-resolved electron time-of-flight photoemission results for ultra-thin Cu will be presented.
Date: November 11, 2004
Creator: Nelson, A J; Dunn, J; van Buuren, T & Hunter, J
Object Type: Article
System: The UNT Digital Library
Rapid Generation of a Nanocrystal-Labeled Peptide Library for Specific Identification of the Bacterium Clostrium Botulinum (open access)

Rapid Generation of a Nanocrystal-Labeled Peptide Library for Specific Identification of the Bacterium Clostrium Botulinum

Several peptide libraries containing up to 2 million unique peptide ligands have been synthesized. The peptides are attached onto a 80 micron resin and the length of these peptide ligands ranges from 5 to 9 amino acid residues. Using a novel calorimetric assay, the libraries were screened for binding to the ganglioside-binding domain of Clostridium Tetanus Toxin, a structural similar analog of the Clostridium Botulinum toxin. Several binding peptide sequences were identified, in which the detailed binding kinetics are currently underway using the Surface Plasmon Resonance (SPR) technique.
Date: November 11, 2004
Creator: Tok, J B
Object Type: Report
System: The UNT Digital Library
Methods for Calibrating Basin-Wide Hydroacoustic Propagation in the Indian Ocean (open access)

Methods for Calibrating Basin-Wide Hydroacoustic Propagation in the Indian Ocean

This collaborative project was designed to test and compare methods for achieving full ocean basin propagation of hydroacoustic signals in the 5-100 Hz frequency band. Plans for a systematic calibration of the International Monitoring System (IMS) for nuclear testing were under consideration in 2000/2001. The results from this project provide information to guide such planning for future ocean basin calibration work. Several acoustic source types were tested during two sea-going experiments and most were successful at generating signals that propagated hundreds to thousands of km to be recorded at the Indian Ocean IMS hydrophone stations. Development and numerical modeling of imploding glass sphere sources was one component of this testing. The intent was to design a relatively simple-to-use source that is not subject to restrictions that can limit use of explosive charges, but whose signal is large enough to propagate 100-1000's km range. Analysis of IMS hydrophone data recording during the experiments was used to illustrate the extent of energy loss during signal propagation and to assess the accuracy with which the small acoustic sources could be located using methods typically employed for nuclear monitoring.
Date: October 11, 2004
Creator: Blackman, D; de Groot-Hedlin, C; Orcutt, J A; Harben, P H; Clarke, D B & Ramirez, A L
Object Type: Report
System: The UNT Digital Library
User Documentation for CVODE v2.2.0 (open access)

User Documentation for CVODE v2.2.0

None
Date: November 11, 2004
Creator: Hindmarsh, A C & Serban, R
Object Type: Text
System: The UNT Digital Library
High pT hadron spectra at RHIC: an overview (open access)

High pT hadron spectra at RHIC: an overview

Recent results on high transverse momentum (p{sub T}) hadron production in p+p, d+Au and Au+Au collisions at the Relativistic Heavy Ion Collider (RHIC) are reviewed. Comparison of the nuclear modification factors, R{sub dAu}(p{sub T}) and R{sub AA}(p{sub T}), demonstrates that the large suppression in central Au+Au collisions is due to strong final-state effects. Theoretical models which incorporate jet quenching via gluon Bremsstrahlung in the dense partonic medium that is expected in central Au+Au collisions at ultra-relativistic energies are shown to reproduce the shape and magnitude of the observed suppression over the range of collision energies so far studied at RHIC.
Date: October 11, 2004
Creator: Klay, J L
Object Type: Article
System: The UNT Digital Library
User Documentation for IDA v2.2.0 (open access)

User Documentation for IDA v2.2.0

None
Date: November 11, 2004
Creator: Hindmarsh, A C & Serban, R
Object Type: Text
System: The UNT Digital Library

Comparison of up-scaling methods in poroelasticity and its generalizations

None
Date: June 11, 2004
Creator: Berryman, James G.
Object Type: Presentation
System: The UNT Digital Library
CRYOGENIC SYSTEM FOR BEPCII SRF CAVITY, IR QUADRUPOLE AND DETECTOR SOLENOID MAGNETS. (open access)

CRYOGENIC SYSTEM FOR BEPCII SRF CAVITY, IR QUADRUPOLE AND DETECTOR SOLENOID MAGNETS.

Beijing Electron-Positron Collider Upgrade (BEPCII) requires three types of superconducting facilities, including one pair of SRF cavities, one pair of interaction region quadrupole magnets, and one detector solenoid magnet. The cryo-plant for BEPCII has a total cooling capacity of 1kW at 4.5K, which is composed of two separate helium refrigerators of 500W each. Two refrigerators share the same gas storage and recovery system. The engineering design for the cryogenic systems, including power leads, control dewars, subcooler, cryogenic valve boxes, cryogenic transfer-lines and cryogenic controls, is completed. The production of its subsystem is under way. This paper summarizes the progress in cryogenics of the BEPCII project.
Date: May 11, 2004
Creator: JIA,J. X. & L., WANG.
Object Type: Article
System: The UNT Digital Library
FEMIS Installation Guide v1.5.3 SR1 Addendum to the FEMIS System Administration Guide v1.5.3 (open access)

FEMIS Installation Guide v1.5.3 SR1 Addendum to the FEMIS System Administration Guide v1.5.3

FEMIS v1.5.3 SR1 includes updates to Section 2.0, FEMIS UNIX Installation, for the FEMIS Installation Guide.
Date: February 11, 2004
Creator: Homer, Brian J.; Carter, Richard J.; Dunkle, Julie R.; Johnson, Sharon M. & Wood, Blanche M.
Object Type: Text
System: The UNT Digital Library
Proteomic Characterization of Host Response to Yersinia pestis (open access)

Proteomic Characterization of Host Response to Yersinia pestis

Host-pathogen interactions result in protein expression changes within both the host and the pathogen. Here, results from proteomic characterization of host response following exposure to Yersinia pestis, the causative agent of plague, and to two near neighbors, Y. pseudotuberculosis and Y. enterocolitica, are reported. Human monocyte-like cells were chosen as a model for macrophage immune response to pathogen exposure. Two-dimensional electrophoresis followed by mass spectrometry was used to identify host proteins with differential expression following exposure to these three closely related Yersinia species. This comparative proteomic characterization of host response clearly shows that host protein expression patterns are distinct for the different pathogen exposures, and contributes to further understanding of Y. pestis virulence and host defense mechanisms. This work also lays the foundation for future studies aimed at defining biomarkers for presymptomatic detection of plague.
Date: May 11, 2004
Creator: Chromy, B.; Perkins, J.; Heidbrink, J.; Gonzales, A.; Murhpy, G.; Fitch, J. P. et al.
Object Type: Article
System: The UNT Digital Library
Simulation Analysis of Inspections of International Travelers at Los Angeles International Airport for US-VISIT (open access)

Simulation Analysis of Inspections of International Travelers at Los Angeles International Airport for US-VISIT

The United States Visitor and Immigrant Status Indicator Technology Program (US-VISIT) will deploy biometric and other systems to identify and track foreign nationals entering and exiting the U.S. Evaluation of the large number of possible policy options and technical configurations for implementation of US-VISIT requires validated system analyses with appropriate tools that can address the requirements of this new program and its processes. Early identification of performance issues and capability gaps will prove critical to the success of the program.
Date: February 11, 2004
Creator: Edmunds, T.; Sholl, P.; Yao, Y.; Gansemer, J.; Cantwell, E.; Prosnitz, D. et al.
Object Type: Report
System: The UNT Digital Library
Simulations of Turbulence Induced Ellipticity Over Large Fields-of-View: The First Step Towards Enabling LSST Weak Lensing Science (open access)

Simulations of Turbulence Induced Ellipticity Over Large Fields-of-View: The First Step Towards Enabling LSST Weak Lensing Science

Atmospheric turbulence can mimic the effects of weak lensing in astronomical images, so it is necessary to understand to what degree turbulence affects weak lensing measurements. In particular, we studied the ellipticity induced upon the point-spread functions (PSFs) of a grid of simulated stars separated by distances (d {approx} 1{prime}) that will be characteristic of Large Synoptic Survey Telescope (LSST) images. We observe that atmospherically induced ellipticity changes on small scales (d < 0.5{prime}) and use linear interpolation between stars separated by d = 0.5{prime} to determine the induced ellipticity everywhere in the field-of-view.
Date: October 11, 2004
Creator: Schlaufman, K
Object Type: Report
System: The UNT Digital Library
Discussion: Reporting and calibration of post-bomb 14C data (open access)

Discussion: Reporting and calibration of post-bomb 14C data

The definitive paper by Stuiver and Polach (1977) established the conventions for reporting of {sup 14}C data for chronological and geophysical studies based on the radioactive decay of {sup 14}C in the sample since the year of sample death or formation. Several ways of reporting {sup 14}C activity levels relative to a standard were also established, but no specific instructions were given for reporting nuclear weapons testing (post-bomb) {sup 14}C levels in samples. Because the use of post-bomb {sup 14}C is becoming more prevalent in forensics, biology, and geosciences, a convention needs to be adopted. We advocate the use of fraction modern with a new symbol F{sup 14}C to prevent confusion with the previously used Fm, which may or may not have been fractionation corrected. We also discuss the calibration of post-bomb {sup 14}C samples and the available datasets and compilations, but do not give a recommendation for a particular dataset.
Date: October 11, 2004
Creator: Reimer, P J; Brown, T A & Reimer, R W
Object Type: Article
System: The UNT Digital Library
Simulating Time-Dependent Energy Transfer Between Crossed Laser Beams in an Expanding Plasma (open access)

Simulating Time-Dependent Energy Transfer Between Crossed Laser Beams in an Expanding Plasma

A coupled mode system is derived to investigate a three-wave parametric instability leading to energy transfer between co-propagating laser beams crossing in a plasma flow. The model includes beams of finite width refracting in a prescribed transverse plasma flow with spatial and temporal gradients in velocity and density. The resulting paraxial light equations are discretized spatially with a Crank-Nicholson-type scheme, and these algebraic constraints are nonlinearly coupled with ordinary differential equations in time that describe the ion acoustic response. The entire nonlinear differential-algebraic system is solved using an adaptive, backward-differencing method coupled with Newton's method. A numerical study is conducted in two dimensions that compares the intensity gain of the fully time-dependent coupled mode system with the gain computed under the further assumption of a strongly-damped ion acoustic response. The results demonstrate a time-dependent gain suppression when the beam diameter is commensurate with the velocity gradient scale length. The gain suppression is shown to depend on time-dependent beam refraction and is interpreted as a time-dependent frequency shift.
Date: October 11, 2004
Creator: Hittinger, J. F.; Dorr, M. R.; Berger, R. L. & Williams, E. A.
Object Type: Article
System: The UNT Digital Library
Cryogenic Facitlity Design in Bepc Ii Superconducting Upgrade. (open access)

Cryogenic Facitlity Design in Bepc Ii Superconducting Upgrade.

Three kinds of superconducting device are to be constructed at interaction regions in the upgrade of Beijing Electron-Positron Collider (BEPCII). Two sets of refrigerators with each capacity of 500W at 4.5K are adopted to provide the refrigeration for them. The cryogenic systems to support the operation of the superconducting facilities are under design by Harbin Institute of Technology in China. This paper presents the current design of main cryogenic facilities.
Date: May 11, 2004
Creator: Jia, L. X.; Wang, L.; Yang, G. D. & Al., Et
Object Type: Article
System: The UNT Digital Library