Livermore Lab's giant laser system will bring star power to Earth (open access)

Livermore Lab's giant laser system will bring star power to Earth

In the 50 years since the laser was first demonstrated in Malibu, California, on May 16, 1960, Lawrence Livermore National Laboratory (LLNL) has been a world leader in laser technology and the home for many of the world's most advanced laser systems. That tradition continues today at LLNL's National Ignition Facility (NIF), the world's most energetic laser system. NIF's completion in March 2009 not only marked the dawn of a new era of scientific research - it could also prove to be the next big step in the quest for a sustainable, carbon-free energy source for the world. NIF consists of 192 laser beams that will focus up to 1.8 million joules of energy on a bb-sized target filled with isotopes of hydrogen - forcing the hydrogen nuclei to collide and fuse in a controlled thermonuclear reaction similar to what happens in the sun and the stars. More energy will be produced by this 'ignition' reaction than the amount of laser energy required to start it. This is the long-sought goal of 'energy gain' that has eluded fusion researchers for more than half a century. Success will be a scientific breakthrough - the first demonstration of fusion ignition in a …
Date: April 8, 2010
Creator: Moses, Edward
Object Type: Article
System: The UNT Digital Library
Aspects of Holography for Theories with Hyperscaling Violation (open access)

Aspects of Holography for Theories with Hyperscaling Violation

None
Date: April 8, 2013
Creator: Dong, Xi; Harrison, Sarah; Kachru, Shamit; Torroba, Gonzalo; Wang, Huajia & /Stanford U., ITP /Stanford U., Phys. Dept. /SLAC
Object Type: Article
System: The UNT Digital Library
Ro-vibrational Relaxation Dynamics of PbF Molecules (open access)

Ro-vibrational Relaxation Dynamics of PbF Molecules

In 1950 Purcell and Ramsey suggested that the electron might have a CP-violating electric dipole moment (e-EDM) proportional to its spin angular momentum. This possibility initiated an ongoing hunt for the e-EDM that has been spurred on by the recognition of the importance of CP-violation to the formation of a matter-dominated universe[2] as well as a difference in magnitude of the Supersymmetric and Standard Model[4] prediction for its value. The current limit on the e-EDM is 1.6E−27 e·cm as determined in a Ramsey beam resonance study of the Tl atom. The PbF molecule provides a unique opportunity to measure the e-EDM. The molecule’s odd electron, heavy mass, and large internal field combine to give it an intrinsic sensitivity to an e-EDM that is over three orders of magnitude bigger than that of the Tl atom. In addition to this increased intrinsic sensitivity, the ground state of the PbF molecule allows for a "magic" electric field at which the magnetic moment vanishes[7]. All of these advantages create an opportunity to significantly lower the current limit on the e-EDM. These advantages can only be realized if an intense source of ground-state PbF molecules can be created and detected with high efficiency. The …
Date: April 8, 2011
Creator: Shafer-Ray, Neil
Object Type: Report
System: The UNT Digital Library
Final Technical Report for DOE Award DE-FG02-05ER63959 (open access)

Final Technical Report for DOE Award DE-FG02-05ER63959

The goals of this work were: (1) to improve the University of Washington shallow cumulus parameterization, first developed by the PI's group for better simulation of shallow oceanic cumulus convection in the MM5 mesoscale model (Bretherton et al., 2004, Mon. Wea. Rev.); (2) to explore its applicability to deep (precipitating) cumulus convection; and (3) to explore fundamental physical issues related to this cumulus parameterization.
Date: April 8, 2011
Creator: Bretherton, Christopher S.
Object Type: Report
System: The UNT Digital Library
Final Technical Report for "Collaborative Research: Regional climate-change projections through next-generation empirical and dynamical models" (open access)

Final Technical Report for "Collaborative Research: Regional climate-change projections through next-generation empirical and dynamical models"

This project was a continuation of previous work under DOE CCPP funding in which we developed a twin approach of non-homogeneous hidden Markov models (NHMMs) and coupled ocean-atmosphere (O-A) intermediate-complexity models (ICMs) to identify the potentially predictable modes of climate variability, and to investigate their impacts on the regional-scale. We have developed a family of latent-variable NHMMs to simulate historical records of daily rainfall, and used them to downscale seasonal predictions. We have also developed empirical mode reduction (EMR) models for gaining insight into the underlying dynamics in observational data and general circulation model (GCM) simulations. Using coupled O-A ICMs, we have identified a new mechanism of interdecadal climate variability, involving the midlatitude oceans’ mesoscale eddy field and nonlinear, persistent atmospheric response to the oceanic anomalies. A related decadal mode is also identified, associated with the oceans’ thermohaline circulation. The goal of the continuation was to build on these ICM results and NHMM/EMR model developments and software to strengthen two key pillars of support for the development and application of climate models for climate change projections on time scales of decades to centuries, namely: (a) dynamical and theoretical understanding of decadal-to-interdecadal oscillations and their predictability; and (b) an interface from …
Date: April 8, 2011
Creator: Kravtsov, S.; Robertson, A. W.; Ghil, M. & Smyth, P. J.
Object Type: Report
System: The UNT Digital Library
GRiP - A flexible approach for calculating risk as a function of consequence, vulnerability, and threat. (open access)

GRiP - A flexible approach for calculating risk as a function of consequence, vulnerability, and threat.

Get a GRiP (Gravitational Risk Procedure) on risk by using an approach inspired by the physics of gravitational forces between body masses! In April 2010, U.S. Department of Homeland Security Special Events staff (Protective Security Advisors [PSAs]) expressed concern about how to calculate risk given measures of consequence, vulnerability, and threat. The PSAs believed that it is not 'right' to assign zero risk, as a multiplicative formula would imply, to cases in which the threat is reported to be extremely small, and perhaps could even be assigned a value of zero, but for which consequences and vulnerability are potentially high. They needed a different way to aggregate the components into an overall measure of risk. To address these concerns, GRiP was proposed and developed. The inspiration for GRiP is Sir Isaac Newton's Universal Law of Gravitation: the attractive force between two bodies is directly proportional to the product of their masses and inversely proportional to the squares of the distance between them. The total force on one body is the sum of the forces from 'other bodies' that influence that body. In the case of risk, the 'other bodies' are the components of risk (R): consequence, vulnerability, and threat (which …
Date: April 8, 2011
Creator: Whitfield, R. G.; Buehring, W. A. & Bassett, G. W. (Decision and Information Sciences)
Object Type: Report
System: The UNT Digital Library
Collaborative Research: Towards Advanced Understanding and Predictive Capability of Climate Change in the Arctic using a High-Resolution Regional Arctic Climate System Model (open access)

Collaborative Research: Towards Advanced Understanding and Predictive Capability of Climate Change in the Arctic using a High-Resolution Regional Arctic Climate System Model

Primary activities are reported in these areas: climate system component studies via one-way coupling experiments; development of the Regional Arctic Climate System Model (RACM); and physical feedback studies focusing on changes in Arctic sea ice using the fully coupled model.
Date: April 8, 2013
Creator: Lettenmaier, Dennis P.
Object Type: Report
System: The UNT Digital Library
Modeling Fission Product Sorption in Graphite Structures (open access)

Modeling Fission Product Sorption in Graphite Structures

The goal of this project is to determine changes in adsorption and desorption of fission products to/from nuclear-grade graphite in response to a changing chemical environment. First, the project team will employ principle calculations and thermodynamic analysis to predict stability of fission products on graphite in the presence of structural defects commonly observed in very high- temperature reactor (VHTR) graphites. Desorption rates will be determined as a function of partial pressure of oxygen and iodine, relative humidity, and temperature. They will then carry out experimental characterization to determine the statistical distribution of structural features. This structural information will yield distributions of binding sites to be used as an input for a sorption model. Sorption isotherms calculated under this project will contribute to understanding of the physical bases of the source terms that are used in higher-level codes that model fission product transport and retention in graphite. The project will include the following tasks: Perform structural characterization of the VHTR graphite to determine crystallographic phases, defect structures and their distribution, volume fraction of coke, and amount of sp2 versus sp3 bonding. This information will be used as guidance for ab initio modeling and as input for sorptivity models; Perform ab initio …
Date: April 8, 2013
Creator: Szlufarska, Izabela; Morgan, Dane & Allen, Todd
Object Type: Report
System: The UNT Digital Library
SMALL-SCALE SAFETY TEST REPORT FOR RDX (SECOND CALIBRATION) (open access)

SMALL-SCALE SAFETY TEST REPORT FOR RDX (SECOND CALIBRATION)

RDX was provided by Indian Head and was dried at 60 C for 16 hours, cooled and kept in a desiccator before use. Please note that the impact testing was done on both pellets and loose powder which resulted in different data. The impact sensitivity on pressed pellets was 34 cm that is greater than that on loose powder, as expected. The impact test data on the loose powder was similar to what Indian Head and LANL got. Remarkable consistent results were observed for test results of loose powder RDX. The average impact sensitivyt (DH{sub 50}) was 21.8 cm and the average friction sensitivity (F{sub 50}) for loose powder was 24.9 kg, respectively. DSC charts showed that peak temperatures and onset temperatures for all 3 runs of RDX samples were almost identical. All electrostatic spark sensitivity was 0/10 at 1.0 J with a 510-ohm resistor in the discharge circuit.
Date: April 8, 2011
Creator: HSU, P C; Reynolds, J G; HSU, P C & Reynolds, J G
Object Type: Report
System: The UNT Digital Library
Coordinated Fault Tolerance for High-Performance Computing (open access)

Coordinated Fault Tolerance for High-Performance Computing

Our work to meet our goal of end-to-end fault tolerance has focused on two areas: (1) improving fault tolerance in various software currently available and widely used throughout the HEC domain and (2) using fault information exchange and coordination to achieve holistic, systemwide fault tolerance and understanding how to design and implement interfaces for integrating fault tolerance features for multiple layers of the software stack—from the application, math libraries, and programming language runtime to other common system software such as jobs schedulers, resource managers, and monitoring tools.
Date: April 8, 2013
Creator: Dongarra, Jack; Bosilca, George & al., et
Object Type: Report
System: The UNT Digital Library
Ultra-Compact High-Efficiency Luminaire for General Illumination (open access)

Ultra-Compact High-Efficiency Luminaire for General Illumination

Cree has developed a new ultra-compact light emitting diode (LED) luminaire capable of providing high efficacy with excellent color quality that can lead to significant energy savings in today‟s commercial and retail applications. This success was based on an integrated development effort tailoring the LED component characteristics, optics, thermal management and driver design for the small footprint to achieve an overall system efficiency of ≥ 70%. A new LED component was designed to provide high brightness and efficacy in a form factor that allowed for a small directional beam with a luminaire housing design able to dissipate the heat effectively using a small physical envelope. A very compact, 90% efficient driver was developed to meet the system performance while not taking away any thermal mass from the heat sink. A 91% efficient secondary optics was designed to maximize efficiency while providing a smooth beam. The reliability of the new LED component was robust under accelerated testing conditions. Luminaires were assembled integrating the novel LED component, secondary optics, heat sink and driver technology to demonstrate the system improvement. Cree has successfully completed this project by developing an ultra-compact LED luminaire that provided 380 lumens at a correlated color temperature (CCT) of …
Date: April 8, 2012
Creator: Lowes, Ted
Object Type: Report
System: The UNT Digital Library
Atmospheric Radiation Measurement Program Climate Research Facility Operations Quarterly Report January 1–March 31, 2010 (open access)

Atmospheric Radiation Measurement Program Climate Research Facility Operations Quarterly Report January 1–March 31, 2010

The U.S. Department of Energy (DOE) requires national user facilities to report time-based operating data. The requirements concern the actual hours of operation (ACTUAL); the estimated maximum operation or uptime goal (OPSMAX), which accounts for planned downtime; and the VARIANCE [1 – (ACTUAL/OPSMAX)], which accounts for unplanned downtime.
Date: April 8, 2010
Creator: Sisterson, D. L.
Object Type: Report
System: The UNT Digital Library
Operations and Maintenance Manual for Large Aperture Scanner System (open access)

Operations and Maintenance Manual for Large Aperture Scanner System

Operations and maintenance manual includes detailed instructions for system assembly, use, and maintenance.
Date: April 8, 2010
Creator: Jones, Anthony M. & Hall, Thomas E.
Object Type: Report
System: The UNT Digital Library
Authorized Limits for the Release of a 25 Ton Locomotive, Serial Number 21547, at the Area 25 Engine Maintenance, Assembly, and Disassembly Facility, Nevada Test Site, Nevada (open access)

Authorized Limits for the Release of a 25 Ton Locomotive, Serial Number 21547, at the Area 25 Engine Maintenance, Assembly, and Disassembly Facility, Nevada Test Site, Nevada

This document contains process knowledge and radiological data and analysis to support approval for release of the 25-ton locomotive, Serial Number 21547, at the Area 25 Engine Maintenance, Assembly, and Disassembly (EMAD) Facility, located on the Nevada Test Site (NTS). The 25-ton locomotive is a small, one-of-a-kind locomotive used to move railcars in support of the Nuclear Engine for Rocket Vehicle Application project. This locomotive was identified as having significant historical value by the Nevada State Railroad Museum in Boulder City, Nevada, where it will be used as a display piece. A substantial effort to characterize the radiological conditions of the locomotive was undertaken by the NTS Management and Operations Contractor, National Security Technologies, LLC (NSTec). During this characterization process, seven small areas on the locomotive had contamination levels that exceeded the NTS release criteria (limits consistent with U.S. Department of Energy [DOE] Order DOE O 5400.5, “Radiation Protection of the Public and the Environment”). The decision was made to perform radiological decontamination of these known accessible impacted areas to further the release process. On February 9, 2010, NSTec personnel completed decontamination of these seven areas to within the NTS release criteria. Although all accessible areas of the locomotive had …
Date: April 8, 2010
Creator: Frenette, Jeremy Gwin and Douglas
Object Type: Report
System: The UNT Digital Library
Fluidized Bed Steam Reforming for Treatment and Immobilization of Low-Activity Waste (open access)

Fluidized Bed Steam Reforming for Treatment and Immobilization of Low-Activity Waste

This report is one of four reports written to provide background information regarding immobilization technologies remaining under consideration for supplemental immobilization of Hanford's low-activity waste. This paper provides the reader a general understanding of fluidized bed steam reforming and its possible application to treat and immobilize Hanford low-activity waste.
Date: April 8, 2011
Creator: Hewitt, W. M.
Object Type: Report
System: The UNT Digital Library
Alternative Neutron Detection Testing Summary (open access)

Alternative Neutron Detection Testing Summary

Radiation portal monitors used for interdiction of illicit materials at borders include highly sensitive neutron detection systems. The main reason for having neutron detection capability is to detect fission neutrons from plutonium. Most currently deployed radiation portal monitors (RPMs) use neutron detectors based upon 3He-filled gas proportional counters, which are the most common large area neutron detector. This type of neutron detector is used in the TSA and other RPMs installed in international locations and in the Ludlum and Science Applications International Corporation RPMs deployed primarily for domestic applications. There is a declining supply of 3He in the world and, thus, methods to reduce the use of this gas in RPMs with minimal changes to the current system designs and sensitivity to cargo-borne neutrons are being investigated. Four technologies have been identified as being currently commercially available, potential alternative neutron detectors to replace the use of 3He in RPMs. These technologies are: 1) Boron trifluoride-filled proportional counters, 2) Boron-lined proportional counters, 3) Lithium-loaded glass fibers, and 4) Coated wavelength-shifting plastic fibers. Reported here is a summary of the testing carried out at Pacific Northwest National Laboratory on these technologies to date, as well as measurements on 3He tubes at various …
Date: April 8, 2010
Creator: Kouzes, Richard T.; Ely, James H.; Erikson, Luke E.; Kernan, Warnick J.; Lintereur, Azaree T.; Siciliano, Edward R. et al.
Object Type: Report
System: The UNT Digital Library
Recommended Changes to Specifications for Demand Controlled Ventilation in California's Title 24 Building Energy Efficiency Standards (open access)

Recommended Changes to Specifications for Demand Controlled Ventilation in California's Title 24 Building Energy Efficiency Standards

In demand-controlled ventilation (DCV), rates of outdoor air ventilation are automatically modulated as occupant density varies. The objective is to keep ventilation rates at or above design specifications and code requirements and also to save energy by avoiding excessive ventilation rates. DCV is most often used in spaces with highly variable and sometime dense occupancy. In almost all cases, carbon dioxide (CO{sub 2}) sensors installed in buildings provide the signal to the ventilation rate control system. People produce and exhale CO{sub 2} as a consequence of their normal metabolic processes; thus, the concentrations of CO{sub 2} inside occupied buildings are higher than the concentrations of CO{sub 2} in the outdoor air. The magnitude of the indoor-outdoor CO{sub 2} concentration difference decreases as the building's ventilation rate per person increases. The difference between the indoor and outdoor CO{sub 2} concentration is also a proxy for the indoor concentrations of other occupant-generated bioeffluents, such as body odors. Reviews of the research literature on DCV indicate a significant potential for energy savings, particularly in buildings or spaces with a high and variable occupancy. Based on modeling, cooling energy savings from applications of DCV are as high as 20%. With support from the California …
Date: April 8, 2010
Creator: Fisk, William J.; Sullivan, Douglas P. & Faulkner, David
Object Type: Report
System: The UNT Digital Library
Fermi level stabilization energy in cadmium oxide (open access)

Fermi level stabilization energy in cadmium oxide

We have studied the effects of high concentrations of native point defects on the electrical and optical properties of CdO. The defects were introduced by irradiation with high energy He+, Ne+, Ar+ and C+ ions. Increasing the irradiation damage with particles heavier than He+ increases the electron concentration until a saturation level of 5x1020 cm-3 is reached. In contrast, due to the ionic character and hence strong dynamic annealing of CdO, irradiation with much lighter He+ stabilizes the electron concentration at a much lower level of 1.7x1020 cm-3. A large shift of the optical absorption edge with increasing electron concentration in irradiated samples is explained by the Burstein-Moss shift corrected for electron-electron and electron-ion interactions. The saturation of the electron concentration and the optical absorption edge energy are consistent with a defect induced stabilization of the Fermi energy at 1 eV above the conduction band edge. The result is in a good agreement with previously determined Fermi level pinning energies on CdO surfaces. The results indicate that CdO shares many similarities with InN, as both materials exhibit extremely large electron affinities and an unprecedented propensity for n-type conductivity.
Date: April 8, 2010
Creator: Speaks, D. T.; Mayer, M. A.; Yu, K. M.; Mao, S. S.; Haller, E. E. & Walukiewicz, W.
Object Type: Article
System: The UNT Digital Library
Zinc distribution and speciation in Arabidopsis halleri x Arabidops is lyrata progenies presenting various zinc accumulation capacities (open access)

Zinc distribution and speciation in Arabidopsis halleri x Arabidops is lyrata progenies presenting various zinc accumulation capacities

- The purpose of this study was to investigate the relationship between the chemical form and localization of zinc (Zn) in plant leaves and their Zn accumulationcapacity. - An interspecific cross between Arabidopsis halleri sp. halleri and Arabidopsis lyrata sp. petrea segregating for Zn accumulation was used. Zinc (Zn) speciation and Zn distribution in the leaves of the parent plants and of selected F1 and F2 progenies were investigated by spectroscopic and microscopic techniques and chemical analyses. - A correlation was observed between the proportion of Zn being in octahedral coordination complexed to organic acids and free in solution (Zn?OAs + Znaq) and Zn content in the leaves. This pool varied between 40percent and 80percent of total leaf Zn depending on the plant studied. Elemental mapping of the leaves revealed different Zn partitioning between the veins and the leaf tissue. The vein : tissue fluorescence ratio was negatively correlated with Zn accumulation. - The higher proportion of Zn?OAs + Znaq and the depletion of the veins in the stronger accumulators are attributed to a higher xylem unloading and vacuolar sequestration in the leaf cells. Elemental distributions in the trichomes were also investigated, and results support the role of carboxyl and⁄ …
Date: April 8, 2010
Creator: Sarret, Geraldine; Willems, Glenda; Isaure, Marie-Pierre; Marcus, Matthew A.; Fakra, Sirine C.; Frerot, Helene et al.
Object Type: Article
System: The UNT Digital Library
"Problems in Web-Based Open Source Information Processing for IT Early Warning" (open access)

"Problems in Web-Based Open Source Information Processing for IT Early Warning"

None
Date: April 8, 2011
Creator: Grothoff, Krista; Brunner, Martin; Hofinger, Hans; Roblee, Christopher & Eckert, Claudia
Object Type: Article
System: The UNT Digital Library
STATISTICAL MECHANICS MODELING OF MESOSCALE DEFORMATION IN METALS (open access)

STATISTICAL MECHANICS MODELING OF MESOSCALE DEFORMATION IN METALS

The research under this project focused on a theoretical and computational modeling of dislocation dynamics of mesoscale deformation of metal single crystals. Specifically, the work aimed to implement a continuum statistical theory of dislocations to understand strain hardening and cell structure formation under monotonic loading. These aspects of crystal deformation are manifestations of the evolution of the underlying dislocation system under mechanical loading. The project had three research tasks: 1) Investigating the statistical characteristics of dislocation systems in deformed crystals. 2) Formulating kinetic equations of dislocations and coupling these kinetics equations and crystal mechanics. 3) Computational solution of coupled crystal mechanics and dislocation kinetics. Comparison of dislocation dynamics predictions with experimental results in the area of statistical properties of dislocations and their field was also a part of the proposed effort. In the first research task, the dislocation dynamics simulation method was used to investigate the spatial, orientation, velocity, and temporal statistics of dynamical dislocation systems, and on the use of the results from this investigation to complete the kinetic description of dislocations. The second task focused on completing the formulation of a kinetic theory of dislocations that respects the discrete nature of crystallographic slip and the physics of dislocation …
Date: April 8, 2013
Creator: El-Azab, Anter
Object Type: Report
System: The UNT Digital Library
Activation of Air and Utilities in the National Ignition Facility (open access)

Activation of Air and Utilities in the National Ignition Facility

Detailed 3-D modeling of the NIF facility is developed to accurately simulate the radiation environment within the NIF. Neutrons streaming outside the NIF Target Chamber will activate the air present inside the Target Bay and the Ar gas inside the laser tubes. Smaller levels of activity are also generated in the Switchyard air and in the Ar portion of the SY laser beam path. The impact of neutron activation of utilities located inside the Target Bay is analyzed for variety of shot types. The impact of activating TB utilities on dose received by maintenance personnel post-shot is analyzed. The current NIF facility model includes all important features of the Target Chamber, shielding system, and building configuration. Flow of activated air from the Target Bay is controlled by the HVAC system. The amount of activated Target Bay air released through the stack is very small and does not pose significant hazard to personnel or the environment. Activation of Switchyard air is negligible. Activation of Target Bay utilities result in a manageable dose rate environment post high yield (20 MJ) shots. The levels of activation generated in air and utilities during D-D and THD shots are small and do not impact work …
Date: April 8, 2010
Creator: Khater, H; Pohl, B & Brererton, S
Object Type: Article
System: The UNT Digital Library
CAST STONE TECHNOLOGY FOR THE TREATMENT AND IMMOBILIZATION OF LOW-ACTIVITY WASTE (open access)

CAST STONE TECHNOLOGY FOR THE TREATMENT AND IMMOBILIZATION OF LOW-ACTIVITY WASTE

Cast stone technology is being evaluated for potential application in the treatment and immobilization of Hanford low-activity waste. The purpose of this document is to provide background information on cast stone technology. The information provided in the report is mainly based on a pre-conceptual design completed in 2003.
Date: April 8, 2011
Creator: Minwall, H. J.
Object Type: Report
System: The UNT Digital Library
LIFE: Recent Developments and Progress (open access)

LIFE: Recent Developments and Progress

Test results from the NIF show excellent progress toward achieving ignition. Experiments designed to verify coupling of the laser energy to the fusion target have shown that the efficiency meets that needed for ignition. Several tests with the cryogenic targets needed for ignition have been performed, and world-record neutron output produced. The National Ignition Campaign is on schedule to meet its 2012 ignition milestone, with the next phase in the campaign due to start later this month. It has been a busy and very productive year. The NIF is in full 24/7 operations and has progressed markedly in the path toward ignition. The long-standing goal of the National Ignition Campaign to demonstrate ignition by the end of FY 2012 is on track. The LIFE plant design has matured considerably, and a delivery plan established based on close interactions with vendors. National-level reviews of fusion are underway, and are due to present initial findings later this year. A value proposition has been drafted for review. The LIFE project is ready to move into the delivery phase.
Date: April 8, 2011
Creator: Anklam, T M
Object Type: Report
System: The UNT Digital Library