Numerical Studies of the Friction Force for the Rhic Electron Cooler. (open access)

Numerical Studies of the Friction Force for the Rhic Electron Cooler.

Accurate calculation of electron cooling times requires an accurate description of the dynamical friction force. The proposed RHIC cooler will require {approx}55 MeV electrons, which must be obtained from an RF linac, leading to very high transverse electron temperatures. A strong solenoid will be used to magnetize the electrons and suppress the transverse temperature, but the achievable magnetized cooling logarithm will not be large. In this paper, we explore the magnetized friction force for parameters of the RHIC cooler, using the VORPAL code [l]. VORPAL can simulate dynamical friction and diffusion coefficients directly from first principles [2]. Various aspects of the fiction force are addressed for the problem of high-energy electron cooling in the RHIC regime.
Date: May 16, 2005
Creator: Fedotov, A. V.; Ben-Zvi, Ilan & Litvinenko, V.
Object Type: Article
System: The UNT Digital Library
Simulations of High-Energy Electron Cooling. (open access)

Simulations of High-Energy Electron Cooling.

High-energy electron cooling of RHIC presents many unique features and challenges. An accurate estimate of the cooling times requires a detailed calculation of the cooling process, which takes place simultaneously with various diffusive mechanisms in RHIC. In addition, many unexplored effects of high-energy cooling in a collider complicate the task of getting very accurate estimates of cooling times. To address these high-energy cooling issues, a detailed study of cooling dynamics based on computer codes is underway at Brookhaven National Laboratory. In this paper, we present an update on code development and its application to the high-energy cooling dynamics studies for RHIC.
Date: May 16, 2005
Creator: Fedotov, A. V.; Ben-Zvi, Ilan; Eidelman, Yu.; Litvinenko, V. & Malitsky, N.
Object Type: Article
System: The UNT Digital Library
Ibs for Ion Distribution Under Electron Cooling. (open access)

Ibs for Ion Distribution Under Electron Cooling.

Standard models of the intra-beam scattering (IBS) are based on the growth of the rms beam parameters for a Gaussian distribution. As a result of electron cooling, the core of beam distribution is cooled much faster than the tails, producing a denser core. In this paper, we compare various approaches to IBS treatment for such distribution. Its impact on the luminosity is also discussed.
Date: May 16, 2005
Creator: Fedotov, A. V.; Ben-Zvi, Ilan; Eidelman, Yu.; Litvinenko, V. & Parzen, G.
Object Type: Article
System: The UNT Digital Library
Iraq: Summary of U.S. Casualties (open access)

Iraq: Summary of U.S. Casualties

This report provides statistics on fatalities during Operation Iraqi Freedom, which began on March 19, 2003, as well as on the number of fatalities since May 1, 2003, plus statistics on those wounded, but not killed, since March 19, 2003.
Date: December 16, 2005
Creator: Fischer, Hannah & O'Bryant, JoAnne
Object Type: Report
System: The UNT Digital Library
Performance Limitations in High-Energy Ion Colliders (open access)

Performance Limitations in High-Energy Ion Colliders

High-energy ion colliders (hadron colliders operating with ions other than protons) are premier research tools for nuclear physics. The collision energy and high luminosity are important design and operations considerations. The experiments also expect flexibility with frequent changes in the collision energy, detector fields, and ion species, including asymmetric collisions. For the creation, acceleration, and storage of bright intense ion beams limits are set by space charge, charge exchange, and intrabeam scattering effects. The latter leads to luminosity lifetimes of only a few hours for intense heavy ions beams. Currently, the Relativistic Heavy Ion Collider (RHIC) at BNL is the only operating high-energy ion collider. Later this decade the Large Hadron Collider (LHC), under construction at CERN, will also run with heavy ions.
Date: May 16, 2005
Creator: Fischer, W.
Object Type: Article
System: The UNT Digital Library
Measurement of Transverse Echoes in Rhic. (open access)

Measurement of Transverse Echoes in Rhic.

Beam echoes are a very sensitive method to measure diffusion, and longitudinal echo measurements were performed in a number of machines. In RHIC, for the first time, a transverse beam echo was observed after applying a dipole kick followed by a quadrupole .kick. After application of the dipole kick, the dipole moment decohered completely due to lattice nonlinearities. When a quadrupole kick is applied at time {tau} after the dipole kick, the beam re-cohered at time 2{tau} thus showing an echo response. We describe the experimental setup and measurement results. In the measurements the dipole and quadrupole kick amplitudes, amplitude dependent tune shift, and the time between dipole and quadrupole kick were varied. In addition, measurements were taken with gold bunches of different intensities. These should exhibit different transverse diffusion rates due to intra-beam scattering.
Date: May 16, 2005
Creator: Fischer, W.; Satogata, T. & Tomas, R.
Object Type: Article
System: The UNT Digital Library
Nanostructured Assemblies of Thermoelectric Composite Materials (open access)

Nanostructured Assemblies of Thermoelectric Composite Materials

None
Date: May 16, 2005
Creator: Fisher, E. R. & Dorhout, P. K.
Object Type: Report
System: The UNT Digital Library
Committee Controls of Agency Decisions (open access)

Committee Controls of Agency Decisions

Congress has a long history of subjecting certain types of executive agency decisions to committee control, either by committees or subcommittees. Especially with the beginning of World War II, the executive branch agreed to committee controls as an accommodation that allowed Congress to delegate authority and funds broadly while using committees to monitor the use of that discretionary authority. These committee-agency arrangements took the form of different procedures: simply notifying the committee, obtaining committee approval, "coming into agreement" understandings, and using the congressional distinction between authorization and appropriation to exercise committee controls. This report explains how and why committee vetoes originated, the constitutional objections raised by the executive branch, the Court’s decision in Chadha, and the continuation of committee review procedures since that time.
Date: November 16, 2005
Creator: Fisher, Louis
Object Type: Report
System: The UNT Digital Library
Global Climate Change: The Kyoto Protocol (open access)

Global Climate Change: The Kyoto Protocol

Responding to concerns that human activities are increasing concentrations of “greenhouse gases” (such as carbon dioxide and methane) in the atmosphere, most nations of the world joined together in 1992 to sign the United Nations Framework Convention on Climate Change (UNFCCC). The United States was one of the first nations to ratify this treaty. It included a legally non-binding, voluntary pledge that the major industrialized/developed nations would reduce their greenhouse gas emissions to 1990 levels by the year 2000, and that all nations would undertake voluntary actions to measure, report, and limit greenhouse gas emissions.
Date: February 16, 2005
Creator: Fletcher, Susan R.
Object Type: Report
System: The UNT Digital Library
CHARACTERIZATION OF PLASTICALLY-INDUCED STRUCTURAL CHANGES IN A Zr-BASED BULK METALLIC GLASS USING POSITRON ANNIHILATION SPECTROCOPY (open access)

CHARACTERIZATION OF PLASTICALLY-INDUCED STRUCTURAL CHANGES IN A Zr-BASED BULK METALLIC GLASS USING POSITRON ANNIHILATION SPECTROCOPY

Flow in metallic glasses is associated with stress-induced cooperative rearrangements of small groups of atoms involving the surrounding free volume. Understanding the details of these rearrangements therefore requires knowledge of the amount and distribution of the free volume and how that distribution evolves with deformation. The present study employs positron annihilation spectroscopy to investigate the free volume change in Zr{sub 58.5}Cu{sub 15.6}Ni{sub 12.8}Al{sub 10.3}Nb{sub 2.8} bulk metallic glass after inhomogeneous plastic deformation by cold rolling and structural relaxation by annealing. Results indicate that the size distribution of open volume sites is at least bimodal. The size and concentration of the larger group, identified as flow defects, changes with processing. Following initial plastic deformation the size of the flow defects increases, consistent with the free volume theory for flow. Following more extensive deformation, however, the size distribution of the positron traps shifts, with much larger open volume sites forming at the expense of the flow defects. This suggests that a critical strain is required for flow defects to coalesce and form more stable nanovoids, which have been observed elsewhere by high resolution TEM. Although these results suggest the presence of three distinct open volume size groups, further analysis indicates that all …
Date: September 16, 2005
Creator: Flores, K M; Kanungo, B P; Glade, S C & Asoka-Kumar, P
Object Type: Article
System: The UNT Digital Library
Excitation function for the production of 262Bh (Z = 107) in theodd-Z projectile reaction 208Pb(55Mn, n) (open access)

Excitation function for the production of 262Bh (Z = 107) in theodd-Z projectile reaction 208Pb(55Mn, n)

The excitation function for production of 262Bh in the odd-Z-projectile reaction 208Pb(55Mn,n) has been measured at three projectile energies using the Berkeley Gas-filled Separator at the Lawrence Berkeley National Laboratory 88-Inch Cyclotron. In total, 33 decay chains originating from 262Bh and 2 decay chains originating from 261Bh were observed. The measured decay properties are in good agreement with previous reports. The maximum cross section of 540 +180 - 150 pb is observed at a lab-frame center-of-target energy of 264.0 MeV and is more than fives times larger than that expected based on previously reported results for production of 262Bh in the analogous even-Z-projectile reaction 209Bi(54Cr,n). Our results indicate that the optimum beam energy in one-neutron-out heavy-ion fusion reactions can be estimated simply using the ''Optimum Energy Rule'' proposed by Swiatecki, Siwek-Wilczynska, and Wilczynski.
Date: May 16, 2005
Creator: Folden, C. M., III; Nelson, S. L.; Dullmann, Ch. E.; Schwantes, J. M.; Sudowe, R.; Zielinski, P. M. et al.
Object Type: Article
System: The UNT Digital Library
Single Cell Proteomics with Ultra-High Sensitivity Mass Spectrometry (open access)

Single Cell Proteomics with Ultra-High Sensitivity Mass Spectrometry

This project was a joint LDRD project between PAT, CMS and NAI with the objective to develop an instrument that analyzes the biochemical composition of single cells in real-time using bioaerosol mass spectrometry (BAMS) combined with advanced laser desorption and ionization techniques. Applications include both biological defense, fundamental cell biology and biomedical research. BAMS analyzes the biochemical composition of single, micrometer-sized particles (such as bacterial cells or spores) that can be directly sampled from air or a suspension. BAMS is based on an earlier development of aerosol time of flight mass spectrometry (ATOFMS) by members of our collaboration [1,2]. Briefly, in ATOFMS and BAMS aerosol particles are sucked directly from the atmosphere into vacuum through a series of small orifices. As the particles approach the ion source region of the mass spectrometer, they cross and scatter light from two CW laser beams separated by a known distance. The timing of the two bursts of scattered light created by each ''tracked'' particle reveals the speed, location and size of the particle. This information then enables the firing of a high-intensity laser such that the resulting laser pulse desorbs and ionizes molecules from the tracked particle just as it reaches the center …
Date: February 16, 2005
Creator: Frank, M
Object Type: Report
System: The UNT Digital Library
Highly Compressed Ion Beam for High Energy Density Science (open access)

Highly Compressed Ion Beam for High Energy Density Science

The Heavy Ion Fusion Virtual National Laboratory is developing the intense ion beams needed to drive matter to the High Energy Density regimes required for Inertial Fusion Energy and other applications. An interim goal is a facility for Warm Dense Matter studies, wherein a target is heated volumetrically without being shocked, so that well-defined states of matter at 1 to 10 eV are generated within a diagnosable region. In the approach they are pursuing, low to medium mass ions with energies just above the Bragg peak are directed onto thin target ''foils,'' which may in fact be foams with mean densities 1% to 10% of solid. This approach complements that being pursued at GSI Darmstadt, wherein high-energy ion beams deposit a small fraction of their energy in a cylindrically target. They present the beam requirements for Warm Dense Matter experiments. The authors discuss neutralized drift compression and final focus experiments and modeling. They describe suitable accelerator architectures based on Drift-Tube Linac, RF, single-gap, Ionization-Front Accelerator, and Pulse-Line Ion Accelerator concepts. The last of these is being pursued experimentally. Finally, they discuss plans toward a user facility for target experiments.
Date: May 16, 2005
Creator: Friedman, A.; Barnard, J. J.; Briggs, R. J.; Callahan, D. A.; Caporaso, G. J.; Celata, C. M. et al.
Object Type: Article
System: The UNT Digital Library
Integrated Gasification Combined Cycle Project 2 Mw Fuel Cell Demonstration (open access)

Integrated Gasification Combined Cycle Project 2 Mw Fuel Cell Demonstration

With about 50% of power generation in the United States derived from coal and projections indicating that coal will continue to be the primary fuel for power generation in the next two decades, the Department of Energy (DOE) Clean Coal Technology Demonstration Program (CCTDP) has been conducted since 1985 to develop innovative, environmentally friendly processes for the world energy market place. The 2 MW Fuel Cell Demonstration was part of the Kentucky Pioneer Energy (KPE) Integrated Gasification Combined Cycle (IGCC) project selected by DOE under Round Five of the Clean Coal Technology Demonstration Program. The participant in the CCTDP V Project was Kentucky Pioneer Energy for the IGCC plant. FuelCell Energy, Inc. (FCE), under subcontract to KPE, was responsible for the design, construction and operation of the 2 MW fuel cell power plant. Duke Fluor Daniel provided engineering design and procurement support for the balance-of-plant skids. Colt Engineering Corporation provided engineering design, fabrication and procurement of the syngas processing skids. Jacobs Applied Technology provided the fabrication of the fuel cell module vessels. Wabash River Energy Ltd (WREL) provided the test site. The 2 MW fuel cell power plant utilizes FuelCell Energy's Direct Fuel Cell (DFC) technology, which is based on …
Date: May 16, 2005
Creator: FuelCell Energy
Object Type: Report
System: The UNT Digital Library
Immigration: Analysis of the Major Provisions of H.R. 418, the REAL ID Act of 2005 (open access)

Immigration: Analysis of the Major Provisions of H.R. 418, the REAL ID Act of 2005

The 109th Congress is considering several issues carried over from the 108th Congress related to immigration enforcement and identification-document security. This report analyzes the major provisions of House-passed H.R. 418, the REAL ID Act of 2005. It describes relevant current law relating to immigration and document-security matters, how House-passed H.R. 418 would alter current law if enacted, and the degree to which the bill duplicates existing law.
Date: February 16, 2005
Creator: Garcia, Michael J.; Lee, Margaret M. & Tatelman, Todd
Object Type: Report
System: The UNT Digital Library
TOTAL ORE PROCESSING INTEGRATION AND MANAGEMENT (open access)

TOTAL ORE PROCESSING INTEGRATION AND MANAGEMENT

The lessons learned from ore segregation test No.3 were presented to Minntac Mine personnel during the reporting period. Ore was segregated by A-Factor, with low values going to Step 1/2 and high values going to Step 3. During the test, the mine maintained the best split possible for the given production and location constraints. During the test, Step 1&2 A-Factor was lowered more than Step 3 was raised. All other ore quality changes were not manipulated, but the segregation by A-Factor affected most of the other qualities. Magnetic iron, coarse tails, fine tails, silica, and grind changed in response to the split. Segregation was achieved by adding ore from HIS to the Step 3 blend and lowering the amount of LC 1&2 and somewhat lowering the amount of LC 3&4. Conversely, Step 1&2 received less HIS with a corresponding increase in LC 1&2. The amount of IBC was increased to both Steps about one-third of the way into the test. For about the center half of the test, LC 3&4 was reduced to both Steps. The most noticeable layer changes were, then: an increase in the HIS split; a decrease in the LC 1&2 split; adding IBC to both Steps; …
Date: May 16, 2005
Creator: Gertsch, Leslie & Gertsch, Richard
Object Type: Report
System: The UNT Digital Library
TOTAL ORE PROCESSING INTEGRATION AND MANAGEMENT (open access)

TOTAL ORE PROCESSING INTEGRATION AND MANAGEMENT

A new dataset to illustrate ordinary, non-segregated operation of the mine and mill has been collected. Beginning in mid-November, it ended on 31 December, 2004. Drill monitoring data for several blast patterns is being analyzed. Figures 1 through 6 represent one of the patterns. Sample preparation for laboratory rock strength tests is underway, for comparison with the density and point-load test results measured last summer. The relationships among data mined from the databases and the ore segregation tests of both mines are being examined, mainly through use of multiple regression analysis. The study is ongoing.
Date: May 16, 2005
Creator: Gertsch, Leslie & Gertsch, Richard
Object Type: Report
System: The UNT Digital Library
Enabling Tool for Innovative Glass Applications - Final Report (open access)

Enabling Tool for Innovative Glass Applications - Final Report

The use of abrasive waterjet (AWJ) cutting systems in the industrial sector has been limited to applications that are difficult to machine using conventional methods. A major factor for this limited use is the high cost of the garnet abrasive currently used. Initial studies indicated that glass can be processed to produce particles with the desired characteristics at a fraction of the existing price of garnet. Inexpensive abrasive waterjet cutting systems would allow a wider array of glass products to be produced while eliminating many existing design limitations. Availability of low-cost abrasive waterjet cutting media would open new markets for glass applications by making glass a more versatile material. A fundamental goal of this project was to scale up and refine the circuit that was established in the initial phase of this project, which using waste glass as a feed stream, could economically produce glass particles displaying high angularity, sharp edges and a low aspect ratio which would prove suitable for use in abrasive waterjet (AWJ) cutting systems. Using commercial scale equipment, demonstration runs were conducted at various manufacturers facilities to further establish that waste glass is a viable source for the production of an inexpensive AWJ media for use …
Date: November 16, 2005
Creator: Gillis, James M.
Object Type: Report
System: The UNT Digital Library
General Relativity&Compact Stars (open access)

General Relativity&Compact Stars

Compact stars--broadly grouped as neutron stars and white dwarfs--are the ashes of luminous stars. One or the other is the fate that awaits the cores of most stars after a lifetime of tens to thousands of millions of years. Whichever of these objects is formed at the end of the life of a particular luminous star, the compact object will live in many respects unchanged from the state in which it was formed. Neutron stars themselves can take several forms--hyperon, hybrid, or strange quark star. Likewise white dwarfs take different forms though only in the dominant nuclear species. A black hole is probably the fate of the most massive stars, an inaccessible region of spacetime into which the entire star, ashes and all, falls at the end of the luminous phase. Neutron stars are the smallest, densest stars known. Like all stars, neutron stars rotate--some as many as a few hundred times a second. A star rotating at such a rate will experience an enormous centrifugal force that must be balanced by gravity or else it will be ripped apart. The balance of the two forces informs us of the lower limit on the stellar density. Neutron stars are 10{sup …
Date: August 16, 2005
Creator: Glendenning, Norman K.
Object Type: Article
System: The UNT Digital Library
Characterization of High-Temperature Laser-Produced Plasmas Using Thomson Scattering (open access)

Characterization of High-Temperature Laser-Produced Plasmas Using Thomson Scattering

Ultraviolet Thomson scattering has been fielded at the Omega Laser Facility to achieve accurate measurements of the plasma conditions in laser-produced high-temperature plasmas. Recent applications to hohlraum targets that have been filled with CH gas or SiO{sub 2} foams have demonstrated a new high temperature plasma regime of importance to laser-plasma interaction studies in a strongly damped regime such as those occurring in indirect drive inertial confinement fusion experiments. The Thomson scattering spectra show the collective ion acoustic features that fit the theory for two ion species plasmas and from which we infer the electron and ion temperature. We find that the electron temperature scales from 2-4 keV when increasing the heater beam energy into the hohlraum from 8-17 kJ, respectively. Simultaneous measurements of the stimulated Raman scattering from a green 527 nm interaction beam show that the reflectivity decreases from 20% to 1% indicating that this instability is strongly damped at high temperatures. These findings support green laser beams as possible driver option for laser-driven fusion experiments.
Date: September 16, 2005
Creator: Glenzer, S H; Froula, D H; Ross, S; Niemann, C; Meezan, N & Divol, L
Object Type: Article
System: The UNT Digital Library
Tax Policy Options After Hurricane Katrina (open access)

Tax Policy Options After Hurricane Katrina

None
Date: September 16, 2005
Creator: Gravelle, Jane G.
Object Type: Report
System: The UNT Digital Library
Control Surveys for Underground Construction of the Superconducting Super Collider (open access)

Control Surveys for Underground Construction of the Superconducting Super Collider

Particular care had to be taken in the design and implementation of the geodetic control systems for the Superconducting Super Collider (SSC) due to stringent accuracy requirements, the demanding tunneling schedule, long duration and large size of the construction effort of the project. The surveying requirements and the design and implementation of the surface and underground control scheme for the precise location of facilities which include approximately 120 km of bored tunnel are discussed. The methodology used for the densification of the surface control networks, the technique used for the transfer of horizontal and vertical control into the underground facilities, and the control traverse scheme employed in the tunnels is described.
Date: August 16, 2005
Creator: Greening, W. J. Trevor; Robinson, Gregory L.; Robbins, Jeffrey S. & Ruland, Robert E.
Object Type: Article
System: The UNT Digital Library
Dispute Settlement in the World Trade Organization: An Overview (open access)

Dispute Settlement in the World Trade Organization: An Overview

This report provides an overview about the Dispute Settlement in the World Trade Organization. Dispute resolution in the World Trade Organization is carried out under the WTO dispute settlement understanding whose rules apply to virtually all WTO agreements.
Date: November 16, 2005
Creator: Grimmett, Jeanne J.
Object Type: Report
System: The UNT Digital Library
OPTIMIZATION OF OPEN MIDPLANE DIPOLE DESIGN FOR LHC IR UPGRADE. (open access)

OPTIMIZATION OF OPEN MIDPLANE DIPOLE DESIGN FOR LHC IR UPGRADE.

This paper presents the optimized designs of an ''open midplane dipole'' [1] for ''dipole first optics'' [2] for the proposed luminosity upgrade of the Large Hadron Collider (LHC). It was found [3] that in this design at luminosity of 10{sup 35} cm{sup -2} s{sup -1}, the peak power density in the coils can be up to two orders of magnitude higher than that at the present baseline luminosity (10{sup 34} cm{sup -2} s{sup -1}). This comes from a large quantity of spray particles from Interaction Point (IP) that is mostly concentrated at the midplane. The ''open midplane dipole'' design is the only design so far that has been found to provide reliable quench-stable operation with a lifetime of the critical components of at least ten years. In addition to a summary of magnetic, mechanical and energy deposition calculations for various iterations, the inherent benefits and challenges associated with the ''open midplane dipole'' design are also discussed. Results are presented for a recently proposed attractive option with the dipole splitted in two with a warm absorber placed between the two [4].
Date: May 16, 2005
Creator: Gupta, R.; Anerella, M.; Ghosh, A.; Harrison, M.; Schmalzle, J.; Wanderer, P. et al.
Object Type: Article
System: The UNT Digital Library