Status of the Nif Power Conditioning System (open access)

Status of the Nif Power Conditioning System

The NIF Power Conditioning System provides the pulsed excitation required to drive flashlamps in the laser's optical amplifiers. Modular in design, each of the 192 Main Energy Storage Modules (MESMs) storage up to 2.2 MJ of electrical energy in its capacitor bank before delivering the energy to 20 pairs of flashlamps in a 400 {micro}s pulse (10% power points). The peak current of each MESM discharge is 0.5 MA. Production, installation, commissioning and operation of the NIF Power Conditioning continue to progress rapidly, with the goals of completing accelerated production in late 2007 and finishing commissioning by early 2008, all the while maintaining an aggressive operations schedule. To date, more than 80% of the required modules have been assembled, shipped and installed in the facility, representing more that 240 MJ of stored energy available for driving NIF flashlamps. The MESMs have displayed outstanding reliability during daily, multiple-shift operations.
Date: July 26, 2007
Creator: Arnold, P.; Hulsey, S.; Ullery, G.; Petersen, D.; Pendleton, D.; Ollis, C. et al.
Object Type: Article
System: The UNT Digital Library
Diffractive J/Psi Production (open access)

Diffractive J/Psi Production

This work presents measurements of two diffractive production ratio for heavy flavour physics with the use of a reconstructed J/{psi} {yields} {mu}{sup +}{mu}{sup -} sample in p{bar p} collisions at {radical}s = 1.96 TeV using the D0 detector at Fermilab Tevatron. These events were selected using the Luminosity Monitor detectors, the calorimeter system and the muon system in a pseudo-rapidity region with range 2.7 {le} |{eta}| {le} 4.4. The measured ratio were estimated to be N{sub diff}{sup J/{psi}}/N{sub total}{sup J/{psi}} = (1.74 {+-} 0.16(stat) {+-} 0.13(syst))% e N{sub diff}{sup b}/N{sub total}{sup b} = (0.79 {+-} 0.11(stat) {+-} 0.23(syst))%.
Date: July 1, 2007
Creator: Assis Jesus, Ana Carolina & U., /Rio de Janeiro Federal
Object Type: Thesis or Dissertation
System: The UNT Digital Library
The Stability and Reversibility of Metallic Borohydrides (open access)

The Stability and Reversibility of Metallic Borohydrides

In effort to develop reversible metallic borohydrides with high hydrogen storage capacity and low dehydriding temperature, several new materials have been synthesized by modifying LiBH{sub 4} with various metal halides and hydrides. The investigation shows that the halide modification effectively reduced the dehydriding temperature through ion exchange interaction. The effective halides are TiCl{sub 3}, TiF{sub 3}, ZnF{sub 2} and AlF{sub 3}. The material LiBH{sub 4}+0.1TiF{sub 3} desorbs 3.5wt% and 8.5wt% hydrogen at 150 C and 450 C respectively. It re-absorbed 6wt% hydrogen at 500 C and 70 bar after dehydrogenation. The XRD of the rehydrided samples confirmed the formation of LiBH{sub 4}. It indicates that the materials are reversible at the conditions given. However, a number of other halides: MgF{sub 2}, MgCl{sub 2}, CaCl{sub 2}, SrCl{sub 2} and FeCl{sub 3}, did not reduce dehydriding temperature of LiBH{sub 4} significantly. TGA-RGA analysis indicated that some halide modified lithium borohydrides such as LiBH{sub 4}+0.1ZnF{sub 2} evolved diborane during dehydrogenation, but some did not such as LiBH{sub 4}+0.1TiCl{sub 3}. The formation of diborane caused unrecoverable capacity loss resulting in irreversibility. It is suggested that the lithium borohydrides modified by the halides containing the metals that can not form metal borides with boron are …
Date: July 27, 2007
Creator: Au, M.
Object Type: Article
System: The UNT Digital Library
Does Price Transparency Improve Market Efficiency? Implications of Empirical Evidence in Other Markets for the Health Sector (open access)

Does Price Transparency Improve Market Efficiency? Implications of Empirical Evidence in Other Markets for the Health Sector

None
Date: July 24, 2007
Creator: Austin, D. Andrew & Gravelle, Jane G.
Object Type: Report
System: The UNT Digital Library
Evaluation of 2004 Toyota Prius Hybrid Electic Drive System Interim Report - Revised (open access)

Evaluation of 2004 Toyota Prius Hybrid Electic Drive System Interim Report - Revised

The 2004 Toyota Prius is a hybrid automobile equipped with a gasoline engine and a battery-powered electric motor. Both of these motive power sources are capable of providing mechanical drive power for the vehicle. The engine can deliver a peak power output of 57 kilowatts (kW) at 5000 revolutions per minute (rpm) while the motor can deliver a peak power output of 50 kW at 1300 rpm. Together, this engine-motor combination has a specified peak power output of 82 kW at a vehicle speed of 85 kilometers per hour (km/h). In operation, the 2004 Prius exhibits superior fuel economy compared to conventionally powered automobiles. Laboratory tests were conducted to evaluate the electrical and mechanical performance of the 2004 Toyota Prius and its hybrid electric drive system. As a hybrid vehicle, the 2004 Prius uses both a gasoline-powered internal combustion engine and a battery-powered electric motor as motive power sources. Innovative algorithms for combining these two power sources results in improved fuel efficiency and reduced emissions compared to traditional automobiles. Initial objectives of the laboratory tests were to measure motor and generator back-electromotive force (emf) voltages and determine gearbox-related power losses over a specified range of shaft speeds and lubricating oil …
Date: July 31, 2007
Creator: Ayers, C. W.; Hsu, J. S.; Marlino, L. D.; Miller, C. W.; Ott, G. W., Jr.; Oland, C. B. et al.
Object Type: Report
System: The UNT Digital Library
Passive Spectroscopic Diagnostics for Magnetically-confined Fusion Plasmas (open access)

Passive Spectroscopic Diagnostics for Magnetically-confined Fusion Plasmas

Spectroscopy of radiation emitted by impurities and hydrogen isotopes plays an important role in the study of magnetically-confined fusion plasmas, both in determining the effects of impurities on plasma behavior and in measurements of plasma parameters such as electron and ion temperatures and densities, particle transport, and particle influx rates. This paper reviews spectroscopic diagnostics of plasma radiation that are excited by collisional processes in the plasma, which are termed 'passive' spectroscopic diagnostics to distinguish them from 'active' spectroscopic diagnostics involving injected particle and laser beams. A brief overview of the ionization balance in hot plasmas and the relevant line and continuum radiation excitation mechanisms is given. Instrumentation in the soft X-ray, vacuum ultraviolet, ultraviolet, visible, and near-infrared regions of the spectrum is described and examples of measurements are given. Paths for further development of these measurements and issues for their implementation in a burning plasma environment are discussed.
Date: July 18, 2007
Creator: B.C. Stratton, M. Bitter, K.W. Hill, D.L. Hillis, and J.T. Hogan
Object Type: Report
System: The UNT Digital Library
Measurement of CKM-angle gamma with Charmed B0 Meson Decays (open access)

Measurement of CKM-angle gamma with Charmed B0 Meson Decays

This thesis reports measurements of the time-dependent CP asymmetries in fully reconstructed B{sup 0} {yields} (D{sup (*){-+}} and B{sup 0} {yields} D{sup {-+}} {rho}{sup {+-}}) decays in approximately 232 million {Upsilon}(4S) {yields} B{bar B} events, collected with the BABAR detector at the PEP-II asymmetric-energy B factory at the Stanford Linear Accelerator Center in California, as published in Ref. [14]. The phenomenon of CP violation allows one to distinguish between matter and antimatter, and, as such, is one of the essential ingredients needed to explain the apparent abundance of matter over antimatter in the universe. The Standard Model describes the observed elementary particles in terms of three generations of quarks and leptons, as well as the weak, electromagnetic, and strong interactions between them. In the Standard Model, CP violation is incorporated in the Cabibbo-Kobayashi-Maskawa (CKM) matrix, which describes the weak interactions between the quarks. The weak interactions between quarks are described by coupling constants that are functions of three real parameters and one irreducible complex phase. The magnitude of all CP violating effects in the Standard Model is related to this complex phase. The measurement of the CP violating phase of the CKM matrix is an important part of the present …
Date: July 17, 2007
Creator: Baak, Max Arjen & /Vrije U., Amsterdam
Object Type: Thesis or Dissertation
System: The UNT Digital Library
INTRACELLULAR COPPER ACCUMULATION ENHANCES THE GROWTH OF KINEOCOCCUS RADIOTOLERANS DURING CHRONIC IRRADIATION (open access)

INTRACELLULAR COPPER ACCUMULATION ENHANCES THE GROWTH OF KINEOCOCCUS RADIOTOLERANS DURING CHRONIC IRRADIATION

The actinobacteria Kineococcus radiotolerans is highly resistant to ionizing radiation, desiccation, and oxidative stress; though the underlying biochemical mechanisms are unknown. The purpose of this study was to explore a possible linkage between the uptake of transition metals and extreme resistance to ionizing radiation and oxidative stress. The effects of 6 different divalent cationic metals on growth were examined in the absence of ionizing radiation. None of the metals tested were stimulatory, though cobalt was inhibitory to growth. In contrast, copper supplementation dramatically increased cell growth during chronic irradiation. K. radiotolerans exhibited specific uptake and intracellular accumulation of copper compared to only a weak response to both iron and manganese supplementation. Copper accumulation sensitized cells to hydrogen peroxide. Acute irradiation induced DNA damage was similar between the copper-loaded culture as the age-synchronized no copper control culture, though low molecular weight DNA was more persistent during post-irradiation recovery in the Cu-loaded culture. Still, the estimated times for genome restoration differed by only 1 hr between treatments. While we cannot discount the possibility that copper fulfills an unexpectedly important biochemical role in a radioactive environment; K. radiotolerans has a high capacity for intracellular copper sequestration, and presumably efficiently coordinated oxidative stress defenses …
Date: July 24, 2007
Creator: Bagwell, C & Charles Milliken, C
Object Type: Article
System: The UNT Digital Library
Multilayers are enabling new science with x-ray free electron lasers (open access)

Multilayers are enabling new science with x-ray free electron lasers

Newly developed multilayer-based mirrors and optical elements enable the imaging of high-resolution structure and ultrafast dynamics of samples with the soft X-ray free electron laser, FLASH, at DESY in Hamburg. The FLASH free-electron laser (FEL) produces intense ultrashort soft X-ray pulses with more than 10{sup 8} times higher peak brightness as compared with the most advanced synchrotron radiation sources. This allows time-resolved X-ray imaging and holography of nanostructures with a temporal resolution approaching 10 fs, opening up new studies of laser-matter interactions and the dynamics of correlated systems. In addition, the ultrafast pulses can be used to obtain structural data before the onset of radiation damage. This vastly increases the dose that can be used to record images of biological samples and hence improving the resolution of images. The extreme power of the X-ray pulses poses a challenge, and new methods are required to harness them. The methods developed here will also pave the way to imaging at upcoming hard-X-ray FELs. With those sources, atomic-resolution imaging of single uncrystallized macromolecules may become possible. In the first demonstration of ultrafast X-ray imaging at FLASH, a micron-sized test object was illuminated by a single focused coherent FEL pulse (Fig. 1). The coherent …
Date: July 17, 2007
Creator: Bajt, S & Chapman, H N
Object Type: Article
System: The UNT Digital Library
A Measurement of the Rate of Muon Capture in Hydrogen Gas andDetermination of the Proton's Induced Pseudoscalar Coupling gP (open access)

A Measurement of the Rate of Muon Capture in Hydrogen Gas andDetermination of the Proton's Induced Pseudoscalar Coupling gP

This dissertation describes a measurement of the rate ofnuclear muon capture by the proton, performed by the MuCap Collaborationusing a new technique based on a time projection chamber operating inultraclean, deuterium-depleted hydrogen gas at room temperature and 1 MPapressure. The hydrogen target's low gas density of 1 percent compared toliquid hydrogen is key to avoiding uncertainties that arise from theformation of muonic molecules. The capture rate was obtained from thedifference between the mu- disappearance rate in hydrogen--as determinedfrom data collected in the experiment's first physics run in fall2004--and the world averagefor the mu+ decay rate. After combining theresults of my analysis with the results from another independent analysisof the 2004 data, the muon capture rate from the hyperfine singlet groundstate of the mu-p atom is found to be Lambda_S = 725.0 +- 17.4 1/s, fromwhich the induced pseudoscalar coupling of the nucleon, gP(q2 = -0.88m2mu)= 7.3 +- 1.1, is extracted. This result for gP is consistent withtheoretical predictions that are based on the approximate chiral symmetryof QCD.
Date: July 10, 2007
Creator: Banks, Thomas Ira
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Plasma Electrode Pockels Cell Subsystem Performance in the National Ignition Facility (open access)

Plasma Electrode Pockels Cell Subsystem Performance in the National Ignition Facility

The Plasma Electrode Pockels Cell (PEPC) subsystem is a key component of the National Ignition Facility, enabling the laser to employ an efficient four-pass main amplifier architecture. PEPC relies on a pulsed power technology to initiate and maintain plasma within the cells and to provide the necessary high voltage bias to the cells nonlinear crystals. Ultimately, nearly 300 high-voltage, high-current pulse generators will be deployed in the NIF in support of PEPC. Production of solid-state plasma pulse generators and thyratron-switched pulse generators is now complete, with the majority of the hardware deployed in the facility. An entire cluster (one-fourth of a complete NIF) has been commissioned and is operating on a routine basis, supporting laser shot operations. Another cluster has been deployed, awaiting final commissioning. Activation and commissioning of new hardware continues to progress in parallel, driving toward a goal of completing the PEPC subsystem in late 2007.
Date: July 27, 2007
Creator: Barbosa, F.; Arnold, P.; Hinz, A.; Zacharias, R.; Ollis, C.; Fulkerson, E. et al.
Object Type: Article
System: The UNT Digital Library
Quintessence, inflation and baryogenesis from a single pseudo-Nambu-Goldstone boson (open access)

Quintessence, inflation and baryogenesis from a single pseudo-Nambu-Goldstone boson

We exhibit a model in which a single pseudo-Nambu-Goldstone boson explains dark energy, inflation and baryogenesis. The model predicts correlated signals in future collider experiments, WIMP searches, proton decay experiments, dark energy probes, and the PLANCK satellite CMB measurements.
Date: July 1, 2007
Creator: Barenboim, Gabriela & Lykken, Joseph D.
Object Type: Article
System: The UNT Digital Library
Radiation requirements and testing of cryogenic thermometers for the ILC (open access)

Radiation requirements and testing of cryogenic thermometers for the ILC

Large quantity of cryogenic temperature sensors will be used for operation of the International Linear Collider (ILC). Most of them will be subject to high radiation doses during the accelerator lifetime. Understanding of particle energy spectra, accumulated radiation dose in thermometers and its impact on performance are vital in establishing technical specification of cryogenic thermometry for the ILC. Realistic MARS15 computer simulations were performed to understand the ILC radiation environment. Simulation results were used to establish radiation dose requirements for commercially available cryogenic thermometers. Two types of thermometers, Cernox{reg_sign} and TVO, were calibrated prior to irradiation using different technique. The sensors were subjected then to up to 200 kGy electron beam irradiation with kinetic energy of 5 MeV, a representative of the situation at the ILC operation. A post-irradiation behavior of the sensors was studied. The paper describes the MARS15 model, simulation results, cryogenic test set-up, irradiation tests, and cryogenic test results.
Date: July 1, 2007
Creator: Barnett, T.; Filippov, Yu.P.; Mokhov, N. V.; Nakao, N.; Klebaner, A. L.; Korenev, S. A. et al.
Object Type: Article
System: The UNT Digital Library
Animal Agriculture: 2007 Farm Bill Issues (open access)

Animal Agriculture: 2007 Farm Bill Issues

None
Date: July 23, 2007
Creator: Becker, Geoffrey S.
Object Type: Report
System: The UNT Digital Library
Country-of-Origin Labeling for Foods (open access)

Country-of-Origin Labeling for Foods

This report provides information about the Country-of-Origin Labeling for Foods. Federal law requires most imports, including many food items to bear labels informing the "ultimate purchaser" of their country of origin.
Date: July 24, 2007
Creator: Becker, Geoffrey S.
Object Type: Report
System: The UNT Digital Library
Farm and Food Support Under USDA’s Section 32 Program (open access)

Farm and Food Support Under USDA’s Section 32 Program

None
Date: July 9, 2007
Creator: Becker, Geoffrey S.
Object Type: Report
System: The UNT Digital Library
Food and Agricultural Imports from China (open access)

Food and Agricultural Imports from China

This report details the information related to U.S food and Agricultural imports from China. The contents include import trends, U.S import safeguards, FDA import refusals, and Chinese food safety challenges.
Date: July 10, 2007
Creator: Becker, Geoffrey S.
Object Type: Report
System: The UNT Digital Library
Food and Agricultural Imports from China (open access)

Food and Agricultural Imports from China

This report details the information related to U.S food and Agricultural imports from China. The contents include import trends, U.S import safeguards, FDA import refusals, and Chinese food safety challenges.
Date: July 17, 2007
Creator: Becker, Geoffrey S.
Object Type: Report
System: The UNT Digital Library
Energy and Water Development: FY2008 Appropriations (open access)

Energy and Water Development: FY2008 Appropriations

None
Date: July 13, 2007
Creator: Behrens, Carl E.; Andrews, Anthony; Bearden, David M.; Carter, Nicole T.; Holt, Mark; Lane, Nic et al.
Object Type: Report
System: The UNT Digital Library
Ionization Thresholds of Small Carbon Clusters: Tunable VUVExperiments and Theory (open access)

Ionization Thresholds of Small Carbon Clusters: Tunable VUVExperiments and Theory

Small carbon clusters (Cn, n = 2-15) are produced in amolecular beam by pulsed laser vaporization and studied with vacuumultraviolet (VUV) photoionization mass spectrometry. The required VUVradiation in the 8-12 eV range is provided by the Advanced Light Source(ALS) at the Lawrence Berkeley National Laboratory. Mass spectra atvarious ionization energies reveal the qualitative relative abundances ofthe neutral carbon clusters produced. By far the most abundant species isC3. Using the tunability of the ALS, ionization threshold spectra arerecorded for the clusters up to 15 atoms in size. The ionizationthresholds are compared to those measured previously with charge-transferbracketing methods. To interpret the ionization thresholds for differentcluster sizes, new ab initio calculations are carried out on the clustersfor n = 4-10. Geometric structures are optimized at the CCSD(T) levelwith cc-pVTZ (or cc-pVDZ) basis sets, and focal point extrapolations areapplied to both neutral and cation species to determine adiabatic andvertical ionization potentials. The comparison of computed and measuredionization potentials makes it possible to investigate the isomericstructures of the neutral clusters produced in this experiment. Themeasurements are inconclusive for the n = 4-6 species because ofunquenched excited electronic states. However, the data provide evidencefor the prominence of linear structures for the n = 7, 9, …
Date: July 31, 2007
Creator: Belau, Leonid; Wheeler, Steven E.; Ticknor, Brian W.; Ahmed, Musahid; Leone, Stephen R.; Allen, Wesley D. et al.
Object Type: Article
System: The UNT Digital Library
Home Performance with ENERGY STAR: Utility Bill Analysis on Homes Participating in Austin Energy's Program (open access)

Home Performance with ENERGY STAR: Utility Bill Analysis on Homes Participating in Austin Energy's Program

Home Performance with ENERGY STAR (HPwES) is a jointly managed program of the U.S. Department of Energy (DOE) and the U.S. Environmental Protection Agency (EPA). This program focuses on improving energy efficiency in existing homes via a whole-house approach to assessing and improving a home's energy performance, and helping to protect the environment. As one of HPwES's local sponsors, Austin Energy's HPwES program offers a complete home energy analysis and a list of recommendations for efficiency improvements, along with cost estimates. To determine the benefits of this program, the National Renewable Energy Laboratory (NREL) collaborated with the Pacific Northwest National Laboratory (PNNL) to conduct a statistical analysis using energy consumption data of HPwES homes provided by Austin Energy. This report provides preliminary estimates of average savings per home from the HPwES Loan Program for the period 1998 through 2006. The results from this preliminary analysis suggest that the HPwES program sponsored by Austin Energy had a very significant impact on reducing average cooling electricity for participating households. Overall, average savings were in the range of 25%-35%, and appear to be robust under various criteria for the number of households included in the analysis.
Date: July 1, 2007
Creator: Belzer, D.; Mosey, G.; Plympton, P. & Dagher, L.
Object Type: Report
System: The UNT Digital Library
In-Situ Continuous Detonation Velocity Measurements Using Fiber-optic Bragg Grating Sensors (open access)

In-Situ Continuous Detonation Velocity Measurements Using Fiber-optic Bragg Grating Sensors

In order to fully calibrate hydrocodes and dynamic chemistry burn models, initiation and detonation research requires continuous measurement of low order detonation velocities as the detonation runs up to full order detonation for a given density and initiation pressure pulse. A novel detector of detonation velocity is presented using a 125 micron diameter optical fiber with an integral chirped fiber Bragg grating as an intrinsic sensor. This fiber is embedded in the explosive under study and interrogated during detonation as the fiber Bragg grating scatters light back along the fiber to a photodiode, producing a return signal dependant on the convolution integral of the grating reflection bandpass, the ASE intensity profile and the photodetector response curve. Detonation velocity is measured as the decrease in reflected light exiting the fiber as the grating is consumed when the detonation reaction zone proceeds along the fiber sensor axis. This small fiber probe causes minimal perturbation to the detonation wave and can measure detonation velocities along path lengths tens of millimeters long. Experimental details of the associated equipment and preliminary data in the form of continuous detonation velocity records within nitromethane and PBX-9502 are presented.
Date: July 25, 2007
Creator: Benterou, J.; Udd, E.; Wilkins, P.; Roeske, F.; Roos, E. & Jackson, D.
Object Type: Article
System: The UNT Digital Library
Clean Cities Annual Metrics Report 2006 (open access)

Clean Cities Annual Metrics Report 2006

Report summarizes Clean Cities coalition accomplishments, including membership, funding, sales of alternative fuel blends, deployment of AFVs and HEVs, idle reduction initiatives, and fuel economy activities.
Date: July 1, 2007
Creator: Bergeron, P. & Putsche, V.
Object Type: Report
System: The UNT Digital Library
Unexpected Cancellations in Gravity Theories (open access)

Unexpected Cancellations in Gravity Theories

Recent computations of scattering amplitudes show that N = 8 supergravity is surprisingly well behaved in the ultraviolet and may even be ultraviolet finite in perturbation theory. The novel cancellations necessary for ultraviolet finiteness first appear at one loop in the guise of the ''no-triangle hypothesis''. We study one-loop amplitudes in pure Einstein gravity and point out the existence of cancellations similar to those found previously in N = 8 supergravity. These cancellations go beyond those found in the one-loop effective action. Using unitarity, this suggests that generic theories of quantum gravity based on the Einstein-Hilbert action may be better behaved in the ultraviolet at higher loops than suggested by naive power counting, though without additional (supersymmetric) cancellations they diverge. We comment on future studies that should be performed to support this proposal.
Date: July 13, 2007
Creator: Bern, Z.; Carrasco, J.J.; /UCLA; Forde, D.; /SLAC, /UCLA; Ita, H. et al.
Object Type: Article
System: The UNT Digital Library