36 Matching Results

Search Results

Results: 1 - 24 next
open access

The National Ignition Facility and the Promise of Inertial Fusion Energy

Description: The National Ignition Facility (NIF) at the Lawrence Livermore National Laboratory (LLNL) in Livermore, CA, is now operational. The NIF is the world's most energetic laser system capable of producing 1.8 MJ and 500 TW of ultraviolet light. By concentrating the energy from its 192 extremely energetic laser beams into a mm{sup 3}-sized target, NIF can produce temperatures above 100 million K, densities of 1,000 g/cm{sup 3}, and pressures 100 billion times atmospheric pressure - conditions that ha… more
Date: December 13, 2010
Creator: Moses, E I
Partner: UNT Libraries Government Documents Department
open access

kt-factorization for Hard Processes in Nuclei

Description: Two widely proposed kt-dependent gluon distributions in the small-x saturation regime are investigated using two particle back-to-back correlations in high energy scattering processes. The Weizsacker-Williams gluon distribution, interpreted as the number density of gluon inside the nucleus, is studied in the quark-antiquark jet correlation in deep inelastic scattering. On the other hand, the unintegrated gluon distribution, defined as the Fourier transform of the color-dipole cross section, is … more
Date: September 13, 2010
Creator: Dominguez, Fabio; Xiao, Bo-Wen & Yuan, Feng
Partner: UNT Libraries Government Documents Department
open access

2010 Water & Aqueous Solutions

Description: Water covers more than two thirds of the surface of the Earth and about the same fraction of water forms the total mass of a human body. Since the early days of our civilization water has also been in the focus of technological developments, starting from converting it to wine to more modern achievements. The meeting will focus on recent advances in experimental, theoretical, and computational understanding of the behavior of the most important and fascinating liquid in a variety of situations … more
Date: August 13, 2010
Creator: Ben-Amotz, Dor
Partner: UNT Libraries Government Documents Department
open access

MIDAS (Material Implementation, Database, and Analysis Source): A comprehensive resource of material properties

Description: MIDAS is aimed to be an easy-to-use and comprehensive common source for material properties including both experimental data and models and their parameters. At LLNL, we will develop MIDAS to be the central repository for material strength related data and models with the long-term goal to encompass other material properties. MIDAS will allow the users to upload experimental data and updated models, to view and read materials data and references, to manipulate models and their parameters, and t… more
Date: December 13, 2010
Creator: Tang, M.; Norquist, P.; Barton, N.; Durrenberger, K.; Florando, J. & Attia, A.
Partner: UNT Libraries Government Documents Department
open access

Evolution of Static Physical Properties in Plutonium by Self-irradiation Damage

Description: The alpha-decay of plutonium leads to the age-related change in physical properties. This paper presents updated results of age-related effects on enriched and reference alloys measured from immersion density, dilatometry, and mechanical tests. After nearly 100 equivalent years of aging, both the immersion density and dilatometry show that the enriched alloys are decreasing in density by less than 0.02% per year and now exhibit a near linear density decrease, without void swelling. The tensile … more
Date: April 13, 2010
Creator: Chung, B W; Lema, K E & Hiromoto, D S
Partner: UNT Libraries Government Documents Department
open access

ROCK DEFORMATION 2010 GORDON RESEARCH CONFERENCE, AUGUST 8-13, 2010

Description: Creep in the crust and mantle is commonly considered a steady-state process. This view prevails despite the fact that earthquakes do not represent steady-state and at the base of the seismogenic zone, for example, the stresses that drive creep must vary with the earthquake cycle. The contribution of transient versus steady-state behavior is not easy to determine from naturally-deformed brittle or plastic rocks and our view of steady-state depends on whether we consider geological or shorter tim… more
Date: August 13, 2010
Creator: Prior, David
Partner: UNT Libraries Government Documents Department
open access

Rhodium-Catalyzed C-C Bond Formation via Heteroatom-Directed C-H Bond Activation

Description: Once considered the 'holy grail' of organometallic chemistry, synthetically useful reactions employing C-H bond activation have increasingly been developed and applied to natural product and drug synthesis over the past decade. The ubiquity and relative low cost of hydrocarbons makes C-H bond functionalization an attractive alternative to classical C-C bond forming reactions such as cross-coupling, which require organohalides and organometallic reagents. In addition to providing an atom economi… more
Date: May 13, 2010
Creator: Colby, Denise; Bergman, Robert & Ellman, Jonathan
Partner: UNT Libraries Government Documents Department
open access

Polarization-selective vortex-core switching by tailored orthogonal Gaussian-pulse currents

Description: We experimentally demonstrate low-power-consumption vortex-core switching in magnetic nanodisks using tailored rotating magnetic fields produced with orthogonal and unipolar Gaussian-pulse currents. The optimal width of the orthogonal pulses and their time delay are found, from analytical and micromagnetic numerical calculations, to be determined only by the angular eigenfrequency {omega}{sub D} for a given vortex-state disk of polarization p, such that {sigma}=1/{omega}{sub D} and {Delta}t={p… more
Date: October 13, 2010
Creator: Jung, H.; Choi, Y. S.; Yoo, M. W.; Im, M. Y. & Kim, S. K.
Partner: UNT Libraries Government Documents Department
open access

Discharge Physics of High Power Impulse Magnetron Sputtering

Description: High power impulse magnetron sputtering (HIPIMS) is pulsed sputtering where the peak power exceeds the time-averaged power by typically two orders of magnitude. The peak power density, averaged over the target area, can reach or exceed 107 W/m2, leading to plasma conditions that make ionization of the sputtered atoms very likely. A brief review of HIPIMS operation is given in a tutorial manner, illustrated by some original data related to the self-sputtering of niobium in argon and krypton. Emp… more
Date: October 13, 2010
Creator: Anders, Andre
Partner: UNT Libraries Government Documents Department
open access

Thermal Degradation Behavior of Siloxane Elastomer Impregnated Carbon Nanotube Areogel Networks

Description: A novel class of nanoporous graphitic carbon foams has been synthesized. Unprecedented properties - electrically conductive, thermally stable (> 1000 C), and mechanically robust. Improved transport properties (DWNT-CA, SWNT-CA) - greater than 100% enhancement in thermal conductivity, 100-400% improvement in electrical conductivity. Rich mechanical deformation behavior (SWNT-CA) - stiff ({approx}100% improvement of elastic modulus), energy dissipation, fracture toughness, and fatigue behavior… more
Date: December 13, 2010
Creator: Lewicki, J P & Worsley, M A
Partner: UNT Libraries Government Documents Department
open access

Mechanical design and analysis of an eight-pole superconducting vector magnet for soft x-ray magnetic dichroism measurements

Description: An eight-pole superconducting magnet is being developed for soft x-ray magnetic dichroism (XMD) experiments at the Advanced Light Source, Lawrence Berkley National Laboratory (LBNL). Eight conical Nb{sub 3}Sn coils with Holmium poles are arranged in octahedral symmetry to form four dipole pairs that provide magnetic fields of up to 5 T in any direction relative to the incoming x-ray beam. The dimensions of the magnet yoke as well as pole taper, diameter, and length were optimized for maximum pe… more
Date: January 13, 2010
Creator: Arbelaez, D.; Black, A.; Prestemon, S.O.; Wang, S.; Chen, J. & Arenholz, E.
Partner: UNT Libraries Government Documents Department
open access

New Meteorlogical Data for Ventsar XL

Description: Every five years Savannah River National Laboratory (SRNL) generates an updated meteorological database to facilitate dosimetric calculations of accident and routine release scenarios for onsite and offsite populations. This information becomes the input of various environmental dosimetry codes run by the Environmental Dosimetry Group (EDG) at SRNL. The three most recent databases prior to the current one were completed for the time periods 1987-1991, 1992-1996, and 1997-2001. The current datab… more
Date: June 13, 2010
Creator: Foley, T. & Jannik, T.
Partner: UNT Libraries Government Documents Department
open access

DEVELOPMENT OF ASME SECTION X CODE RULES FOR HIGH PRESSURE COMPOSITE HYDROGEN PRESSURE VESSELS WITH NON-LOAD SHARING LINERS

Description: The Boiler and Pressure Vessel Project Team on Hydrogen Tanks was formed in 2004 to develop Code rules to address the various needs that had been identified for the design and construction of up to 15000 psi hydrogen storage vessel. One of these needs was the development of Code rules for high pressure composite vessels with non-load sharing liners for stationary applications. In 2009, ASME approved new Appendix 8, for Section X Code which contains the rules for these vessels. These vessels are… more
Date: April 13, 2010
Creator: Rawls, G.; Newhouse, N.; Rana, M.; Shelley, B. & Gorman, M.
Partner: UNT Libraries Government Documents Department
open access

Environmental Reactivity of Solid-State Hydrogen Systems: Fundamental Testing and Evaluation

Description: In order to enable the commercial acceptance of solid state hydrogen storage materials and systems it is important to understand the risks associated with the environmental exposure of various materials. In some instances, these materials are sensitive to the environment surrounding the material and the behavior is unique and independent to each material. The development of testing procedures to evaluate a material's behavior with different environmental exposures is a critical need. In some ca… more
Date: December 13, 2010
Creator: James, C.; Cortes-Concepcion, J.; Anton, D. & Tamburello, D.
Partner: UNT Libraries Government Documents Department
open access

Automatic Model Order Reduction

Description: No Description Available.
Date: December 13, 2010
Creator: White, D. A.
Partner: UNT Libraries Government Documents Department
open access

National Ignition Facility (NIF) Neutron time-of-flight (nTOF) Measurements

Description: The first three of eighteen neutron time-of-flight (nTOF) channels have been installed at the National Ignition Facility (NIF). The role of these detectors includes yield, temperature, and bang time measurements. This article focuses on nTOF data analysis and quality of results obtained for the first set of experiments to use all 192 NIF beams. Targets produced up to 2 x 10{sup 10} 2.45-MeV neutrons for initial testing of the nTOF detectors. Differences in neutron scattering at the OMEGA laser … more
Date: May 13, 2010
Creator: Lerche, R. A.; Glebov, V. Y.; Moran, M. J.; McNaney, J. M.; Kilkenny, J. D.; Eckart, M. et al.
Partner: UNT Libraries Government Documents Department
open access

A high-efficiency spin-resolved photoemission spectrometer combining time-of-flight spectroscopy with exchange-scattering polarimetry

Description: We describe a spin-resolved electron spectrometer capable of uniquely efficient and high energy resolution measurements. Spin analysis is obtained through polarimetry based on low-energy exchange scattering from a ferromagnetic thin-film target. This approach can achieve a similar analyzing power (Sherman function) as state-of-the-art Mott scattering polarimeters, but with as much as 100 times improved efficiency due to increased reflectivity. Performance is further enhanced by integrating the … more
Date: April 13, 2010
Creator: Jozwiak, Chris M.; Graff, Jeff; Lebedev, Gennadi; Andresen, Nord; Schmid, Andreas; Fedorov, Alexei et al.
Partner: UNT Libraries Government Documents Department
open access

Increased Efficiency in SI Engine with Air Replaced by Oxygen in Argon Mixture

Description: Basic engine thermodynamics predicts that spark ignited engine efficiency is a function of both the compression ratio of the engine and the specific heat ratio of the working fluid. In practice the compression ratio of the engine is often limited due to knock. Both higher specific heat ratio and higher compression ratio lead to higher end gas temperatures and increase the likelihood of knock. In actual engine cycles, heat transfer losses increase at higher compression ratios and limit efficienc… more
Date: January 13, 2010
Creator: Killingsworth, N J; Rapp, V H; Flowers, D L; Aceves, S M; Chen, J & Dibble, R
Partner: UNT Libraries Government Documents Department
open access

Detoxification of Outfall Water Using Natural Organic Matter

Description: To protect stream organisms in an ephemeral stream at the Savannah River Site, a proposed National Pollutant Discharge Elimination System (NPDES) permit reduced the copper limit from 25 {micro}g/l to 6 {micro}g/l at Outfall H-12. Efforts to reduce copper in the wastewater and stormwater draining to this outfall did not succeed in bringing copper levels below this limit. Numerous treatment methods were considered, including traditional methods such as ion exchange and natural treatment alternati… more
Date: July 13, 2010
Creator: Halverson, N.; Looney, B.; Millings, M.; Nichols, R.; Noonkester, J. & Payne, B.
Partner: UNT Libraries Government Documents Department
open access

Model for Initiation of Quality Factor Degradation at High Accelerating Fields in Superconducting Radio-Frequency Cavaties

Description: A model for the onset of the reduction in SRF cavity quality factor, the so-called Q-drop, at high accelerating electric fields is presented. Since magnetic fields at the cavity equator are tied to accelerating electric fields by a simple geometric factor, the onset of magnetic flux penetration determines the onset of Q-drop. We consider breakdown of the surface barrier at triangular grooves to predict the magnetic field of first flux penetration H{sub pen}. Such defects were argued to be the w… more
Date: July 13, 2010
Creator: Dzyuba, A.; U., /Fermilab /Novosibirsk State; Romanenko, A.; /Fermilab & Cooley, L. D.
Partner: UNT Libraries Government Documents Department
open access

FUEL CYCLE POTENTIAL WASTE FOR DISPOSITION

Description: The United States (U.S.) currently utilizes a once-through fuel cycle where used nuclear fuel (UNF) is stored on-site in either wet pools or in dry storage systems with ultimate disposal in a deep mined geologic repository envisioned. Within the Department of Energy's (DOE) Office of Nuclear Energy (DOE-NE), the Fuel Cycle Research and Development Program (FCR&D) develops options to the current commercial fuel cycle management strategy to enable the safe, secure, economic, and sustainable e… more
Date: October 13, 2010
Creator: Jones, R. & Carter, J.
Partner: UNT Libraries Government Documents Department
open access

Simulation of e-cloud driven instability and its attenuation using a simulated feedback system in the CERN SPS

Description: Electron clouds have been shown to trigger fast growing instabilities on proton beams circulating in the SPS, and a feedback system to control the single-bunch instabilities is under active development. We present the latest improvements to the WARP-POSINST simulation framework and feedback model, and its application to the self-consistent simulations of two consecutive bunches interacting with an electron cloud in the SPS. Simulations using an idealized feedback system exhibit adequate mitigat… more
Date: December 13, 2010
Creator: Vay, J. L. & Furman, M. A.
Partner: UNT Libraries Government Documents Department
open access

Quark mass variation constraints from Big Bang nucleosynthesis

Description: We study the impact on the primordial abundances of light elements created of a variation of the quark masses at the time of Big Bang nucleosynthesis (BBN). In order to navigate through the particle and nuclear physics required to connect quark masses to binding energies and reaction rates in a model-independent way we use lattice QCD data and an hierarchy of effective field theories. We find that the measured {sup 4}He abundances put a bound of {delta}-1% {approx}< m{sub q}/m{sub 1} {approx… more
Date: December 13, 2010
Creator: Bedaque, P.; Luu, T. & Platter, L.
Partner: UNT Libraries Government Documents Department
Back to Top of Screen