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2011 Computation Directorate Annual Report (open access)

2011 Computation Directorate Annual Report

From its founding in 1952 until today, Lawrence Livermore National Laboratory (LLNL) has made significant strategic investments to develop high performance computing (HPC) and its application to national security and basic science. Now, 60 years later, the Computation Directorate and its myriad resources and capabilities have become a key enabler for LLNL programs and an integral part of the effort to support our nation's nuclear deterrent and, more broadly, national security. In addition, the technological innovation HPC makes possible is seen as vital to the nation's economic vitality. LLNL, along with other national laboratories, is working to make supercomputing capabilities and expertise available to industry to boost the nation's global competitiveness. LLNL is on the brink of an exciting milestone with the 2012 deployment of Sequoia, the National Nuclear Security Administration's (NNSA's) 20-petaFLOP/s resource that will apply uncertainty quantification to weapons science. Sequoia will bring LLNL's total computing power to more than 23 petaFLOP/s-all brought to bear on basic science and national security needs. The computing systems at LLNL provide game-changing capabilities. Sequoia and other next-generation platforms will enable predictive simulation in the coming decade and leverage industry trends, such as massively parallel and multicore processors, to run petascale applications. …
Date: April 11, 2012
Creator: Crawford, D. L.
Object Type: Report
System: The UNT Digital Library
Final Report (open access)

Final Report

Our research program was aimed at elucidating the nature of proton transport in ionomer membranes by means of a combination of analytical theory and molecular modeling. There were two broad thrusts. The first of these was directed towards understanding the equilibrium structure of Nafion and related polymers at various levels of hydration. The second thrust was concerned with the transport of protons through a membrane of this type. The research on structure proceeded by building on existing work, but with the introduction of some novel techniques, among which is a hybrid Molecular Dynamics--Monte Carlo approach. This method permits rapid computations by temporarily decoupling the motion of the polar side chains from that of the perfluorinated backbone, while still retaining the essential aspects of the constraint that phase separation can only continue to a very limited degree. Competition between an elastic energy due to this constraint and the tendency to phase separation lead to the equilibrium structure, which turns out to be qualitatively different at different levels of hydration. The use of a carefully formulated dielectric function was necessary to achieve accurate results. The work on transport of protons in Nafion-like membranes also involved a combination of theory and simulation. Atomistic …
Date: November 11, 2012
Creator: Taylor, Philip L.
Object Type: Report
System: The UNT Digital Library
A Linac Simulation Code for Macro-particles Tracking and Steering Algorithm Implementation (open access)

A Linac Simulation Code for Macro-particles Tracking and Steering Algorithm Implementation

None
Date: May 11, 2012
Creator: Sun, Yipeng
Object Type: Report
System: The UNT Digital Library
LHC Abort Gap Cleaning Studies During Luminosity Operation (open access)

LHC Abort Gap Cleaning Studies During Luminosity Operation

The presence of significant intensities of un-bunched beam is a potentially serious issue in the LHC. Procedures using damper kickers for cleaning both the Abort Gap (AG) and the buckets targeted for injection, are currently in operation at flat bottom. Recent observations of relatively high population of the AG during physics runs brought up the need for AG cleaning during luminosity operation. In this paper the results of experimental studies performed in October 2011 are presented.
Date: May 11, 2012
Creator: Gianfelice-Wendt, E.; Bartmann, W.; Boccardi, A.; Bracco, C.; Bravin, E.; Goddard, B. et al.
Object Type: Article
System: The UNT Digital Library
Assessment of an ORION-based experimental platform for measuring the opacity of high-temperature and high-density plasma (open access)

Assessment of an ORION-based experimental platform for measuring the opacity of high-temperature and high-density plasma

The following provides an assessment of an experimental platform based on the ORION laser at AWE Aldermasten, England, for measuring the opacity of high-temperature and high-density LTE plasmas. The specific points addressed are (1) the range of electron density and temperature that can be achieved with short-pulse beams alone, as well as (2) by means of compression with a long-pulse beam; (3) the accuracy with which electron density, electron temperature, and absolute emissivity can be measured; (4) the use of pulse shaping to increase the sample density to above solid density; (5) the effect that target materials and target design have on maintaining spatial uniformity of the sample, and (6) the need for additional diagnostics to produce and characterize samples for decisive measurements.
Date: June 11, 2012
Creator: Beiersdorfer, P; Schneider, M & Shepherd, R
Object Type: Report
System: The UNT Digital Library
Fast-ion Energy Loss During TAE Avalanches in the National Spherical Torus Experiment (open access)

Fast-ion Energy Loss During TAE Avalanches in the National Spherical Torus Experiment

Strong TAE avalanches on NSTX, the National Spherical Torus Experiment [M. Ono, et al., Nucl. Fusion 40 (2000) 557] are typically correlated with drops in the neutron rate in the range of 5% - 15%. In previous studies of avalanches in L-mode plasmas, these neutron drops were found to be consistent with modeled losses of fast ions. Here we expand the study to TAE avalanches in NSTX H-mode plasmas with improved analysis techniques. At the measured TAE mode amplitudes, simulations with the ORBIT code predict that fast ion losses are negligible. However, the simulations predict that the TAE scatter the fast ions in energy, resulting in a small (≈ 6%) drop in fast ion β. The net decrease in energy of the fast ions is sufficient to account for the bulk of the drop in neutron rate, even in the absence of fast ion losses. This loss of energy from the fast ion population is comparable to the estimated energy lost by damping from the Alfven wave during the burst. The previously studied TAE avalanches in L-mode are re-evaluated using an improved calculation of the potential fluctuations in the ORBIT code.
Date: July 11, 2012
Creator: Fredrickson, E D; Darrow, D S; Gorelenkov, N N; Kramer, G J; Kubota, S; Podesta, M et al.
Object Type: Report
System: The UNT Digital Library
Corrosion Testing of Carbon Steel in Oxalic Acid that Contains Dissolved Iron (open access)

Corrosion Testing of Carbon Steel in Oxalic Acid that Contains Dissolved Iron

Radioactive liquid waste has been stored in underground carbon steel tanks for nearly 60 years at the Savannah River Site. The site is currently in the process of removing the waste from these tanks in order to place it into vitrified, stable state for longer term storage. The last stage in the removal sequence is a chemical cleaning step that breaks up and dissolves metal oxide solids that cannot be easily pumped out of the tank. Oxalic acid (OA) will be used to chemically clean the tanks after waste retrieval is completed. The waste tanks at SRS were constructed from carbon steel materials and thus are vulnerable to corrosion in acidic media. In addition to structural impacts, the impact of corrosion on the hydrogen generated during the process must be assessed. Electrochemical and coupon immersion tests were used to investigate the corrosion mechanism at anticipated process conditions. The testing showed that the corrosion rates were dependent upon the reduction of the iron species that had dissolved in solution. Initial corrosion rates were elevated due to the reduction of the ferric species to ferrous species. At later times, as the ferric species depleted, the corrosion rate decreased. On the other hand, …
Date: October 11, 2012
Creator: Wiersma, Bruce J.; Mickalonis, John I. & Subramanian, Karthik H.
Object Type: Article
System: The UNT Digital Library
Report on the Feasibility of Pu Photoelectron Spectroscopy with Microscopic and Nanoscopic Samples at NSLSII (open access)

Report on the Feasibility of Pu Photoelectron Spectroscopy with Microscopic and Nanoscopic Samples at NSLSII

None
Date: September 11, 2012
Creator: Tobin, J G
Object Type: Report
System: The UNT Digital Library
Shubnikov-de Haas Oscillations in the Bulk Rashba Semiconductor BiTeI (open access)

Shubnikov-de Haas Oscillations in the Bulk Rashba Semiconductor BiTeI

Bulk magnetoresistance quantum oscillations are observed in high quality single crystal samples of BiTeI. This compound shows an extremely large internal spin-orbit coupling, associated with the polarity of the alternating Bi, Te, and I layers perpendicular to the c-axis. The corresponding areas of the inner and outer Fermi surfaces around the A-point show good agreement with theoretical calculations, demonstrating that the intrinsic bulk Rashba-type splitting is nearly 360 meV, comparable to the largest spin-orbit coupling generated in heterostructures and at surfaces.
Date: July 11, 2012
Creator: Bell, C.; Bahramy, M.S.; Murakawa, H.; Checkelsky, J.G.; Arita, R.; Kaneko, Y. et al.
Object Type: Article
System: The UNT Digital Library
Dynamically Adjustable Wind Turbine Blades (open access)

Dynamically Adjustable Wind Turbine Blades

Advanced Research Projects Agency-Energy project sheet summarizing general information about a new program to develop wind turbines with more efficient control systems (project title "Adaptive Turbine Blades: Blown Wing Technology for Low-Cost Wind Power") including critical needs, innovation and advantages, impacts, and contract information. This sheet is the first open solicitation, announcing funding opportunities for involvement in the project.
Date: May 11, 2012
Creator: Caitin Inc.
Object Type: Text
System: The UNT Digital Library
Pu(IV) Intrinsic Colloid Stability in the Presence of Montmorillonite at 25 & 80 C (open access)

Pu(IV) Intrinsic Colloid Stability in the Presence of Montmorillonite at 25 & 80 C

None
Date: June 11, 2012
Creator: Zhao, P.; Kersting, A. B.; Dai, Z. & Zavarin, M.
Object Type: Report
System: The UNT Digital Library
Operation Tomodachi: Answers, Data Products,and Lessons Learned from the U.S. Department of Energy's Consequence Management Response Team (CMRT) to the Fukushima-Daiichi Reactor Accident (open access)

Operation Tomodachi: Answers, Data Products,and Lessons Learned from the U.S. Department of Energy's Consequence Management Response Team (CMRT) to the Fukushima-Daiichi Reactor Accident

This slide-show presents the DOE response to the Fukushima Diaiichi disaster, including aerial and ground monitoring, issues for which the team had not trained or planned for, and questions from decision makers.
Date: July 11, 2012
Creator: Hopkins, R.
Object Type: Article
System: The UNT Digital Library
Charge transport properties of CdMnTe radiation detectors (open access)

Charge transport properties of CdMnTe radiation detectors

Growth, fabrication and characterization of indium-doped cadmium manganese telluride (CdMnTe)radiation detectors have been described. Alpha-particle spectroscopy measurements and time resolved current transient measurements have yielded an average charge collection efficiency approaching 100 %. Spatially resolved charge collection efficiency maps have been produced for a range of detector bias voltages. Inhomogeneities in the charge transport of the CdMnTe crystals have been associated with chains of tellurium inclusions within the detector bulk. Further, it has been shown that the role of tellurium inclusions in degrading chargecollection is reduced with increasing values of bias voltage. The electron transit time was determined from time of flight measurements. From the dependence of drift velocity on applied electric field the electron mobility was found to be n = (718 55) cm2/Vs at room temperature.
Date: April 11, 2012
Creator: Kim, K.; Rafiel, R.; Boardman, M.; Reinhard, I.; Sarbutt, A.; Watt, G. et al.
Object Type: Report
System: The UNT Digital Library
U.S. Environmental Protection Agency (EPA) Response to Final OIG Report Dated September 26, 2011, "Procedural Review of Greenhouse Gases Endangerment Finding Data Quality Processes", Report No. 11-P-0702 (open access)

U.S. Environmental Protection Agency (EPA) Response to Final OIG Report Dated September 26, 2011, "Procedural Review of Greenhouse Gases Endangerment Finding Data Quality Processes", Report No. 11-P-0702

EPA response to Office of the Inspector General (OIG) final report "Procedural Review of Greenhouse Gases Endangerment Finding Data Quality Processes" (Project No. OPE-FY10-0017), dated September 26, 2011.
Date: January 11, 2012
Creator: United States. Environmental Protection Agency.
Object Type: Text
System: The UNT Digital Library
Emergency Assistance for Agricultural Land Rehabilitation (open access)

Emergency Assistance for Agricultural Land Rehabilitation

This report discusses the U.S. Department of Agriculture's (USDA) several permanently authorized programs to help producers recover from natural disasters. Most of these programs offer financial assistance to producers for a loss in the production of crops or livestock. In addition to the production assistance programs, USDA also has several permanent disaster assistance programs that help producers repair damaged crop and forest land following natural disasters.
Date: December 11, 2012
Creator: Stubbs, Megan
Object Type: Report
System: The UNT Digital Library
The Uniformed and Overseas Citizens Absentee Voting Act: Overview and Issues (open access)

The Uniformed and Overseas Citizens Absentee Voting Act: Overview and Issues

This report discusses the Uniformed and Overseas Citizens Absentee Voting Act (UOCAVA), under which members of the uniformed services and U.S. citizens who live abroad are eligible to register and vote absentee in federal elections. The report discusses recent improvements to UOCAVA, necessary as the result of controversy surrounding ballots received in Florida from absentee voters in the 2000 presidential election. The report also discusses related legislation, such as the National Defense Authorization Act for FY2010, which provided for a major overhaul of UOCAVA.
Date: July 11, 2012
Creator: Coleman, Kevin J.
Object Type: Report
System: The UNT Digital Library
Trade Adjustment Assistance for Workers (open access)

Trade Adjustment Assistance for Workers

This report provides background on the Trade Adjustment Assistance for Workers (TAA) program. After a brief introduction, it discusses TAA eligibility and benefits as set by TAAEA. It then describes how the program is funded and administered. The report concludes by presenting data on recent application activity and benefit usage.
Date: July 11, 2012
Creator: Collins, Benjamin
Object Type: Report
System: The UNT Digital Library
Judicial Activity Concerning Enemy Combatant Detainees: Major Court Rulings (open access)

Judicial Activity Concerning Enemy Combatant Detainees: Major Court Rulings

None
Date: December 11, 2012
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Next-Generation Tunable Targets for Laser-Compression Experiments (open access)

Next-Generation Tunable Targets for Laser-Compression Experiments

None
Date: December 11, 2012
Creator: Jeanloz, R & Millot, M
Object Type: Report
System: The UNT Digital Library
Recovering Large Volumes of Homogeneously Shocked Samples (open access)

Recovering Large Volumes of Homogeneously Shocked Samples

None
Date: December 11, 2012
Creator: Stewart, S. T.
Object Type: Report
System: The UNT Digital Library
Regeneration of Tissues and Organs Using Autologous Cells (open access)

Regeneration of Tissues and Organs Using Autologous Cells

The proposed work aims to address three major challenges to the field of regenerative medicine: 1) the growth and expansion of regenerative cells outside the body in controlled in vitro environments, 2) supportive vascular supply for large tissue engineered constructs, and 3) interactive biomaterials that can orchestrate tissue development in vivo. Toward this goal, we have engaged a team of scientists with expertise in cell and molecular biology, physiology, biomaterials, controlled release, nanomaterials, tissue engineering, bioengineering, and clinical medicine to address all three challenges. This combination of resources, combined with the vast infrastructure of the WFIRM, have brought to bear on projects to discover and test new sources of autologous cells that can be used therapeutically, novel methods to improve vascular support for engineered tissues in vivo, and to develop intelligent biomaterials and bioreactor systems that interact favorably with stem and progenitor cells to drive tissue maturation. The Institute’s ongoing programs are aimed at developing regenerative medicine technologies that employ a patient’s own cells to help restore or replace tissue and organ function. This DOE program has provided a means to solve some of the vexing problems that are germane to many tissue engineering applications, regardless of tissue type or …
Date: October 11, 2012
Creator: Anthony Atala, M.D.
Object Type: Report
System: The UNT Digital Library
PILOT-SCALE REMOVAL OF FLUORIDE FROM LEGACY PLUTONIUM MATERIALS USING VACUUM SALT DISTILLATION (open access)

PILOT-SCALE REMOVAL OF FLUORIDE FROM LEGACY PLUTONIUM MATERIALS USING VACUUM SALT DISTILLATION

Between September 2009 and January 2011, the Savannah River National Laboratory (SRNL) and HB-Line designed, developed, tested, and successfully deployed a system for the distillation of chloride salts. In 2011, SRNL adapted the technology for the removal of fluoride from fluoride-bearing salts. The method involved an in situ reaction between potassium hydroxide (KOH) and the fluoride salt to yield potassium fluoride (KF) and the corresponding oxide. The KF and excess KOH can be distilled below 1000{deg}C using vacuum salt distillation (VSD). The apparatus for vacuum distillation contains a zone heated by a furnace and a zone actively cooled using either recirculated water or compressed air. During a vacuum distillation operation, a sample boat containing the feed material is placed into the apparatus while it is cool, and the system is sealed. The system is evacuated using a vacuum pump. Once a sufficient vacuum is attaned, heating begins. Volatile salts distill from the heated zone to the cooled zone where they condense, leaving behind the non-volatile material in the feed boat. Studies discussed in this report were performed involving the use of non-radioactive simulants in small-scale and pilot-scale systems as well as radioactive testing of a small-scale system with plutonium-bearing materials. …
Date: September 11, 2012
Creator: Pierce, R. A. & Pak, D. J.
Object Type: Report
System: The UNT Digital Library
Fermi Large Area Telescope Measurements of the Diffuse Gamma-Ray Emission at Intermediate Galactic Latitudes (open access)

Fermi Large Area Telescope Measurements of the Diffuse Gamma-Ray Emission at Intermediate Galactic Latitudes

The diffuse galactic {gamma}-ray emission is produced by cosmic rays (CRs) interacting with the interstellar gas and radiation field. Measurements by the Energetic Gamma-Ray Experiment Telescope (EGRET) instrument on the Compton Gamma-Ray Observatory indicated excess {gamma}-ray emission {ge}1 GeV relative to diffuse galactic {gamma}-ray emission models consistent with directly measured CR spectra (the so-called 'EGRET GeV excess'). The Large Area Telescope (LAT) instrument on the Fermi Gamma-Ray Space Telescope has measured the diffuse {gamma}-ray emission with improved sensitivity and resolution compared to EGRET. We report on LAT measurements for energies 100 MeV to 10 GeV and galactic latitudes 10{sup o} {le} |b| {le} 20{sup o}. The LAT spectrum for this region of the sky is well reproduced by a diffuse galactic {gamma}-ray emission model that is consistent with local CR spectra and inconsistent with the EGRET GeV excess.
Date: April 11, 2012
Creator: Abdo, A. A.; Ackermann, M.; Ajello, M.; Anderson, B.; Atwood, W. B.; Axelsson, M. et al.
Object Type: Article
System: The UNT Digital Library
Optimization of Extinction Efficiency in the 8-GeV Mu2e Beam Line (open access)

Optimization of Extinction Efficiency in the 8-GeV Mu2e Beam Line

A muon-to-electron conversion experiment at Fermilab, Mu2e, is being designed to probe for new physics beyond the standard model at mass scales up to 10{sup 4} TeV. For this experiment, the advance in experimental sensitivity will be four orders of magnitude when compared to existing data on charged lepton flavor violation. The muon beam will be produced by delivering a proton beam contained in short 100-ns bunches onto a muon production target, with an inter-bunch separation of about 1700 ns. A critical requirement of the experiment is to ensure a low level of background at the muon detector consistent with the required sensitivity. To meet the sensitivity requirement, protons that reach the target between bunches must be suppressed by an enormous factor, so that an extinction factor, defined as a number of background protons between main bunches per proton in such a bunch, should not exceed 10{sup -9}. This paper describes the advanced beam optics and results of numerical modeling with STRUCT and MARS codes for a beam line with a collimation system that allows us to achieve the experimental extinction factor of one per billion.
Date: May 11, 2012
Creator: Rakhno, I. L.; Drozhdin, A. I.; Johnstone, C.; Mokhov, N. V. & Prebys, E.
Object Type: Article
System: The UNT Digital Library