The Physics of Edge Resonant Magnetic Perturbations in Hot Tokamak Plasmas (open access)

The Physics of Edge Resonant Magnetic Perturbations in Hot Tokamak Plasmas

None
Date: June 13, 2006
Creator: Evans, T. E.; Burrell, K. H.; Fenstermacher, M. E.; Moyer, R. A.; Osborne, T. H.; Schaffer, M. J. et al.
Object Type: Article
System: The UNT Digital Library
Edge Stability and Transport Control with Resonant Magnetic Perturbations in Collisionless Tokamak Plasmas (open access)

Edge Stability and Transport Control with Resonant Magnetic Perturbations in Collisionless Tokamak Plasmas

A critical issue for fusion plasma research is the erosion of the first wall of the experimental device due to impulsive heating from repetitive edge magneto-hydrodynamic (MHD) instabilities known as 'edge-localized modes' (ELMs). Here, we show that the addition of small resonant magnetic field perturbations completely eliminates ELMs while maintaining a steady-state high-confinement (H-mode) plasma. These perturbations induce a chaotic behavior in the magnetic field lines, which reduces the edge pressure gradient below the ELM instability threshold. The pressure gradient reduction results from a reduction in particle content of the plasma, rather than an increase in the electron thermal transport. This is inconsistent with the predictions of stochastic electron heat transport theory. These results provide a first experimental test of stochastic transport theory in a highly rotating, hot, collisionless plasma and demonstrate a promising solution to the critical issue of controlling edge instabilities in fusion plasma devices.
Date: June 13, 2006
Creator: Evans, T. E.; Moyer, R. A.; Burrell, K. H.; Fenstermacher, M. E.; Joseph, I.; Leonard, A. W. et al.
Object Type: Article
System: The UNT Digital Library
Waste Isolation Pilot Plant 2005 Site Environmental Report (open access)

Waste Isolation Pilot Plant 2005 Site Environmental Report

The purpose of this report is to provide information needed by the DOE to assess WIPP's environmental performance and to make WIPP environmental information available to stakeholders and members of the public. This report has been prepared in accordance with DOE Order 231.1A and DOE guidance. This report documents WIPP's environmental monitoring programs and their results for 2004. The WIPP Project is authorized by the DOE National Security and Military Applications of Nuclear Energy Authorization Act of 1980 (Pub. L. 96-164). After more than 20 years of scientific study and public input, WIPP received its first shipment of waste on March 26, 1999. Located in southeastern New Mexico, WIPP is the nation's first underground repository permitted to safely and permanently dispose of TRU radioactive and mixed waste (as defined in the WIPP LWA) generated through defense activities and programs. TRU waste is defined, in the WIPP LWA, as radioactive waste containing more than 100 nanocuries (3,700 becquerels [Bq]) of alpha-emitting TRU isotopes per gram of waste, with half-lives greater than 20 years except for high-level waste, waste that has been determined not to require the degree of isolation required by the disposal regulations, and waste the U.S. Nuclear Regulatory Commission …
Date: October 13, 2006
Creator: Services, Washington Regulatory and Environmental
Object Type: Report
System: The UNT Digital Library
Avoiding the Haircut: Potential Ways to Enhance the Value of theUSDA's Section 9006 Program (open access)

Avoiding the Haircut: Potential Ways to Enhance the Value of theUSDA's Section 9006 Program

Section 9006 of Title IX of The Farm Security and Rural Investment Act of 2002 (the '2002 Farm Bill') established the Renewable Energy Systems and Energy Efficiency Improvements Program (the 'Section 9006 program'). Administered by the United States Department of Agriculture (USDA), the Section 9006 program provides grants, loan guarantees, and - perhaps in the future - direct loans to farmers, ranchers, and rural small businesses for assistance with purchasing renewable energy systems and making energy efficiency improvements. In the three rounds of Section 9006 funding to date (FY03-FY05), roughly 40% of all grant dollars in aggregate have been awarded to 'large' (defined as > 100 kW) wind projects. Such projects are also typically eligible for the Federal Production Tax Credit (PTC) codified in Section 45 of the US tax code. Because the PTC provides a significant amount of value to a wind project, most 'large wind' applicants to the Section 9006 program have also tried to take advantage of the PTC. Through what are known as 'anti-double-dipping' or, more colloquially, 'haircut' provisions, however, the size of the PTC is reduced if a project receives certain other forms of governmental support. Specifically, Section 45(b)(3) of the US tax code reduces …
Date: July 13, 2006
Creator: Bolinger, Mark
Object Type: Report
System: The UNT Digital Library
SATB1 tethers multiple gene loci to reprogram expression profiledriving breast cancer metastasis (open access)

SATB1 tethers multiple gene loci to reprogram expression profiledriving breast cancer metastasis

Global changes in gene expression occur during tumor progression, as indicated by expression profiling of metastatic tumors. How this occurs is poorly understood. SATB1 functions as a genome organizer by folding chromatin via tethering multiple genomic loci and recruiting chromatin remodeling enzymes to regulate chromatin structure and expression of a large number of genes. Here we show that SATB1 is expressed at high levels in aggressive breast cancer cells, and is undetectable in non-malignant breast epithelial cells. Importantly, RNAi-mediated removal of SATB1 from highly-aggressive MDA-MB-231 cells altered the expression levels of over 1200 genes, restored breast-like acinar polarity in three-dimensional cultures, and prevented the metastastic phenotype in vivo. Conversely, overexpression of SATB1 in the less-aggressive breast cancer cell line Hs578T altered the gene expression profile and increased metastasis dramatically in vivo. Thus, SATB1 is a global regulator of gene expression in breast cancer cells, directly regulating crucial metastasis-associated genes, including ERRB2 (HER2/NEU), TGF-{beta}1, matrix metalloproteinase 3, and metastasin. The identification of SATB1 as a protein that re-programs chromatin organization and transcription profiles to promote breast cancer metastasis suggests a new model for metastasis and may provide means of therapeutic intervention.
Date: July 13, 2006
Creator: Han, Hye-Jung; Kohwi, Yoshinori & Kohwi-Shigematsu, Terumi
Object Type: Article
System: The UNT Digital Library
Transmission Electron Microscopy Study of InN Nanorods (open access)

Transmission Electron Microscopy Study of InN Nanorods

InN nanorods were grown on a, c-, and r-plane of sapphire and also on Si (111) and GaN (0001) by non-catalytic, template-free hydride metal-organic vapor phase epitaxy and studied by transmission electron microscopy, electron energy loss (EELS) and photoluminescence (PL) at room temperature. These nanocrystals have different shapes and different faceting depending on the substrate used and their crystallographic orientation. EELS measurements have confirmed the high purity of these crystals. The observed PL peak was in the range of 0.9-0.95 eV. The strongest PL intensity was observed for the nanocrystals with the larger diameters.
Date: July 13, 2006
Creator: Liliental-Weber, Z.; Li, X.; Kryliouk, Olga; Park, H.J.; Mangum,J. & Anderson, T.
Object Type: Article
System: The UNT Digital Library
Incorporation of aqueous reaction kinetics and biodegradation intoTOUGHREACT: Application of a multi-region model to hydrobiogeoChemicaltransport of denitrification and sulfate reduction (open access)

Incorporation of aqueous reaction kinetics and biodegradation intoTOUGHREACT: Application of a multi-region model to hydrobiogeoChemicaltransport of denitrification and sulfate reduction

The need to consider aqueous and sorption kinetics andmicrobiological processes arises in many subsurface problems. Ageneral-rate expression has been implemented into the TOUGHREACTsimulator, which considers multiple mechanisms (pathways) and includesmultiple product, Monod, and inhibition terms. This paper presents aformulation for incorporating kinetic rates among primary species intomass-balance equations. The space discretization used is based on aflexible integral finite difference approach that uses irregular griddingto model bio-geologic structures. A general multi-region model forhydrological transport interacted with microbiological and geochemicalprocesses is proposed. A 1-D reactive transport problem with kineticbiodegradation and sorption was used to test the enhanced simulator,which involves the processes that occur when a pulse of water containingNTA (nitrylotriacetate) and cobalt is injected into a column. The currentsimulation results agree very well with those obtained with othersimulators. The applicability of this general multi-region model wasvalidated by results from a published column experiment ofdenitrification and sulfate reduction. The matches with measured nitrateand sulfate concentrations were adjusted with the interficial areabetween mobile hydrological and immobile biological regions. Resultssuggest that TOUGHREACT can not only be a useful interpretative tool forbiogeochemical experiments, but also can produce insight into processesand parameters of microscopic diffusion and their interplay withbiogeochemical reactions. The geometric- and process-based multi-regionmodel may provide …
Date: July 13, 2006
Creator: Xu, Tianfu
Object Type: Article
System: The UNT Digital Library
Cleanup Verification Package for the 118-B-6, 108-B Solid Waste Burial Ground (open access)

Cleanup Verification Package for the 118-B-6, 108-B Solid Waste Burial Ground

This cleanup verification package documents completion of remedial action for the 118-B-6, 108-B Solid Waste Burial Ground. The 118-B-6 site consisted of 2 concrete pipes buried vertically in the ground and capped by a concrete pad with steel lids. The site was used for the disposal of wastes from the "metal line" of the P-10 Tritium Separation Project.
Date: June 13, 2006
Creator: Proctor, M. L.
Object Type: Report
System: The UNT Digital Library
ANALYSIS RESULTS FOR BUILDING 241 702-AZ A TRAIN (open access)

ANALYSIS RESULTS FOR BUILDING 241 702-AZ A TRAIN

This report presents the analyses results for three samples obtained under RPP-PLAN-28509, Sampling and Analysis Plan for Building 241 702-AZ A Train. The sampling and analysis was done in response to problem evaluation request number PER-2004-6139, 702-AZ Filter Rooms Need Radiological Cleanup Efforts.
Date: December 13, 2006
Creator: JB, DUNCAN; JM, FRYE; CA, COOKE; SW, LI & FJ, BROCKMAN
Object Type: Report
System: The UNT Digital Library
Cleanup Verification Package for the 300 VTS Waste Site (open access)

Cleanup Verification Package for the 300 VTS Waste Site

This cleanup verification package documents completion of remedial action for the 300 Area Vitrification Test Site, also known as the 300 VTS site. The site was used by Pacific Northwest National Laboratory as a field demonstration site for in situ vitrification of soils containing simulated waste.
Date: March 13, 2006
Creator: Mitchell, S. W. Clark and T. H.
Object Type: Report
System: The UNT Digital Library
Germanium-Based Detectors for Gamma-Ray Imaging andSpectroscopy (open access)

Germanium-Based Detectors for Gamma-Ray Imaging andSpectroscopy

Germanium-based detectors are the standard technology usedfor gamma-ray spectroscopy when high efficiency and excellent energyresolution are desired. By dividing the electrical contacts on thesedetectors into segments, the locations of the gamma-ray interactionevents within the detectors can be determined as well as the depositedenergies. This enables simultaneous gamma-ray imaging and spectroscopyand leads to applications in the areas of astronomy, nuclear physics,environmental remediation, nuclear nonproliferation, and homelandsecurity. Producing the fine-pitched electrode segmentation oftenrequired for imaging has been problematic in the past. To address thisissue, we have developed an amorphous-semiconductor contact technology.Using this technology, fully passivated detectors with closely spacedcontacts can be produced using a simple fabrication process. The currentstate of the amorphous-semiconductor contact technology and thechallenges that remain will be given in this paper.
Date: October 13, 2006
Creator: Amman, Mark; Luke, Paul N. & Boggs, Steven E.
Object Type: Article
System: The UNT Digital Library
Adventures in Laser Produced Plasma Research (open access)

Adventures in Laser Produced Plasma Research

In the UK the study of laser produced plasmas and their applications began in the universities and evolved to a current system where the research is mainly carried out at the Rutherford Appleton Laboratory Central Laser Facility ( CLF) which is provided to support the universities. My own research work has been closely tied to this evolution and in this review I describe the history with particular reference to my participation in it.
Date: January 13, 2006
Creator: Key, M.
Object Type: Book
System: The UNT Digital Library
Achievable magnetic fields of super-ferric helical undulators for the ILC. (open access)

Achievable magnetic fields of super-ferric helical undulators for the ILC.

The magnetic fields on the beam axis of helical undulators for the proposed International Linear Collider (ILC) gamma-ray production were calculated for undulator periods of 10 mm and 12 mm. The calculation assumed the use of low-carbon steel for the magnetic poles and a beam chamber outer diameter of 6.3 mm. Using NbTi superconducting coils at 4.2 K, the on-axis field for a 10-mm-period undulator was 0.62 T at the critical current density. The field for a 12-mm undulator period was 0.95 T, which gives a K value of 1.06. The K value for an 11-mm undulator with Nb{sub 3}Sn superconducting coils was estimated to about 1.1.
Date: April 13, 2006
Creator: Kim, S. H.
Object Type: Report
System: The UNT Digital Library
Time-Resolved FT-IR Spectroscopy of CO Hydrogenation overSupported Ru Catalyst at 700K (open access)

Time-Resolved FT-IR Spectroscopy of CO Hydrogenation overSupported Ru Catalyst at 700K

Time-resolved FT-IR spectra of carbon monoxide hydrogenation over alumina-supported ruthenium were recorded on the millisecond timescale at 703 K using various H{sub 2} concentrations (1 atm total pressure). Adsorbed carbon monoxide was detected along with gas phase products methane (3016 and 1306 cm{sup -1}), water (sharp bands from 1900 - 1300 cm{sup -1}), and carbon dioxide (2348 cm{sup -1}). No other surface species were detected other than adsorbed carbon monoxide. The rate of formation of methane (2.5 {+-} 0.4 s{sup -1}) coincides with the rate of formation of carbon dioxide (3.4 {+-} 0.6 s{sup -1}), and bands due to water are observed to grow in over time. These results establish that methane and carbon dioxide originate from the same intermediate. The adsorbed carbon monoxide band is broad and unsymmetrical with a maximum at 2010 cm{sup -1} in spectra observed at 36 ms that shifts over 3000 ms to 1960 cm{sup -1} due to decreasing amounts of adsorbed carbon monoxide. Kinetic analysis of the adsorbed carbon monoxide band reveals that only a portion of the band can be temporally linked to gas phase products that we observe over the first 1000 ms of catalysis. This result suggests that we are observing …
Date: February 13, 2006
Creator: Wasylenko, Walter & Frei, Heinz
Object Type: Article
System: The UNT Digital Library
Theory and Simulation of Warm Dense Matter Targets (open access)

Theory and Simulation of Warm Dense Matter Targets

We present simulations and analysis of the heating of warm dense matter foils by ion beams with ion energy less than one MeV per nucleon to target temperatures of order one eV. Simulations were carried out using the multi-physics radiation hydrodynamics code HYDRA and comparisons are made with analysis and the code DPC. We simulate possible targets for a proposed experiment at LBNL (the so-called Neutralized Drift Compression Experiment, NDCXII) for studies of warm dense matter. We compare the dynamics of ideally heated targets, under several assumed equation of states, exploring dynamics in the two-phase (fluid-vapor) regime.
Date: July 13, 2006
Creator: Barnard, J. J.; Armijo, J.; More, R. M.; Friedman, A.; Kaganovich, I.; Logan, B. G. et al.
Object Type: Article
System: The UNT Digital Library
Integrated Global Nuclear Materials Management - Preliminary Concepts - (open access)

Integrated Global Nuclear Materials Management - Preliminary Concepts -

Approach to Connect Global Objectives and Local Actions: (1) Articulate global objectives into a hierarchy of subsystem requirements and local attributes and measures; (2) Establish a baseline system and viable alternatives through the interactions and relationships (e.g., networks) of local system elements and their options; (3) Evaluate performance of system alternatives and develop improved nuclear material management strategies and technologies; and (4) The need to address greatest concerns first (prioritized or graded approach) and to make tradeoffs among implementation options and competing objectives entails a risk-based approach. IGNMM could provide a systematic understanding of global nuclear materials management and evolutionarily improve and integrate the management through an active architecture, using for example, situation awareness, system models, methods, technologies, and international cooperation. Different tools would be used within the overall framework to address individual issues on the desired geographic scale that could be easily linked to broader analyses. Life-cycle system analyses would allow for evaluating material path alternatives on an integrated global scale. Disconnects, overlaps, technical options, and alternatives for optimizing nuclear materials processes could be evaluated in an integrated manner.
Date: July 13, 2006
Creator: Dreicer, M; Jones, E & Richardson, J
Object Type: Article
System: The UNT Digital Library
Sequencing and Analysis of Neanderthal Genomic DNA (open access)

Sequencing and Analysis of Neanderthal Genomic DNA

Recovery and analysis of multiple Neanderthal autosomalsequences using a metagenomic approach reveals that modern humans andNeanderthals split ~;400,000 years ago, without significant evidence ofsubsequent admixture.
Date: June 13, 2006
Creator: Noonan, James P.; Coop, Graham; Kudaravalli, Sridhar; Smith,Doug; Krause, Johannes; Alessi, Joe et al.
Object Type: Article
System: The UNT Digital Library
Radiocarbon Based Ages and Growth Rates: Hawaiian Deep Sea Corals (open access)

Radiocarbon Based Ages and Growth Rates: Hawaiian Deep Sea Corals

The radial growth rates and ages of three different groups of Hawaiian deep-sea 'corals' were determined using radiocarbon measurements. Specimens of Corallium secundum, Gerardia sp., and Leiopathes glaberrima, were collected from 450 {+-} 40 m at the Makapuu deep-sea coral bed using a submersible (PISCES V). Specimens of Antipathes dichotoma were collected at 50 m off Lahaina, Maui. The primary source of carbon to the calcitic C. secundum skeleton is in situ dissolved inorganic carbon (DIC). Using bomb {sup 14}C time markers we calculate radial growth rates of {approx} 170 {micro}m y{sup -1} and ages of 68-75 years on specimens as tall as 28 cm of C. secundum. Gerardia sp., A. dichotoma, and L. glaberrima have proteinaceous skeletons and labile particulate organic carbon (POC) is their primary source of architectural carbon. Using {sup 14}C we calculate a radial growth rate of 15 {micro}m y{sup -1} and an age of 807 {+-} 30 years for a live collected Gerardia sp., showing that these organisms are extremely long lived. Inner and outer {sup 14}C measurements on four sub-fossil Gerardia spp. samples produce similar growth rate estimates (range 14-45 {micro}m y{sup -1}) and ages (range 450-2742 years) as observed for the live collected …
Date: January 13, 2006
Creator: Roark, E. B.; Guilderson, T. P.; Dunbar, R. B. & Ingram, B. L.
Object Type: Article
System: The UNT Digital Library
Novel Methods for Binding Disparate Materials (open access)

Novel Methods for Binding Disparate Materials

This project was intended to advance the science of surface bonding in order to provide the functionality demanded by target fabrication requirements, as well as similar needs in other fields of importance to LLNL. We have developed and demonstrated a very powerful capability, i.e. 'single molecule force spectroscopy', that allows the strength of individual chemical bonds to be measured. This project focused on long chain molecules that are covalently bound to surfaces on one end and have complementary reactive groups that have the potential for bridging between surfaces. In biological systems, long chain tethers provide the mechanism for adhesion between dissimilar surfaces, e.g. bacteria adhesion to cells, and were found useful for developing the methodology. Polymer tethers offer the means to bridge across finite surface roughness and have the potential of forming thin, well-characterized bonds on a variety of surfaces.
Date: February 13, 2006
Creator: McElfresh, M W; Rudd, R E; Ratto, T V & Langry, K C
Object Type: Report
System: The UNT Digital Library
Physics of reshock and mixing in single-mode Richtmyer-Meshkov instability (open access)

Physics of reshock and mixing in single-mode Richtmyer-Meshkov instability

The ninth-order weighted essentially non-oscillatory (WENO) shock-capturing method is used to investigate the physics of reshock and mixing in two-dimensional single-mode Richtmyer-Meshkov instability to late times. The initial conditions and computational domain were adapted from the Mach 1.21 air(acetone)/SF{sub 6} shock tube experiment of Collins and Jacobs [J. Fluid Mech. 464, 113 (2002)]: the growth of the bubble and spike perturbation amplitudes from fifth- and ninth-order WENO simulations of this experiment were compared to the predictions of amplitude growth models, and were shown to be in very good agreement with the experimental data prior to reshock [Latini, Schilling and Don, Phys. Fluids (2007), in press]. In the present investigation, the density, vorticity, baroclinic vorticity production, and simulated density Schlieren fields are first presented to qualitatively describe reshock. The baroclinic circulation deposition on the interface is shown to agree with the predictions of the Samtaney and Zabusky [J. Fluid Mech. 269, 45 (1994)] model and linear instability theory. The time-evolution of the positive and negative circulation on the interface is considered before and after reshock: it is shown that the circulations are equal before, as well as after reshock, until the interaction of the reflected rarefaction with the layer leads to …
Date: December 13, 2006
Creator: Schilling, O; Latini, M & Don, W
Object Type: Article
System: The UNT Digital Library
Protein Classification Based on Analysis of Local Sequence-Structure Correspondence (open access)

Protein Classification Based on Analysis of Local Sequence-Structure Correspondence

None
Date: February 13, 2006
Creator: Zemla, A T
Object Type: Report
System: The UNT Digital Library
Diffusion through Carbon Nanotube Semipermeable membranes (open access)

Diffusion through Carbon Nanotube Semipermeable membranes

The goal of this project is to measure transport through CNTs and study effects of confinement at molecular scale. This work is motivated by several simulation papers in high profile journals that predict significantly higher transport rates of gases and liquids through carbon nanotubes as compared with similarly-sized nanomaterials (e.g. zeolites). The predictions are based on the effects of confinement, atomically smooth pore walls and high pore density. Our work will provide the first measurements that would compare to and hopefully validate the simulations. Gas flux is predicted to be >1000X greater for SWNTs versus zeolitesi. A high flux of 6-30 H2O/NT/ns {approx} 8-40 L/min for a 1cm{sup 2} membrane is also predicted. Neutron diffraction measurements indicate existence of a 1D water chain within a cylindrical ice sheet inside carbon nanotubes, which is consistent with the predictions of the simulation. The enabling experimental platform that we are developing is a semipermeable membrane made out of vertically aligned carbon nanotubes with gaps between nanotubes filled so that the transport occurs through the nanotubes. The major challenges of this project included: (1) Growth of CNTs in the suitable vertically aligned configuration, especially the single wall carbon nanotubes; (2) Development of a process …
Date: February 13, 2006
Creator: Bakajin, O
Object Type: Report
System: The UNT Digital Library
Comment on "Paleoclassical Transport in Low-Collisionality Toroidal Plasmas" (open access)

Comment on "Paleoclassical Transport in Low-Collisionality Toroidal Plasmas"

Paleoclassical transport [1] is a recently proposed fundamental process that is claimed to occur in resistive plasmas and to be missing in the collisional drift-kinetic equations (DKE) in standard use. In this Comment we raise three puzzles presented by paleoclassical transport as developed in [1], one to do with conservation and two concerning uniqueness.
Date: October 13, 2006
Creator: LoDestro, L. L.
Object Type: Article
System: The UNT Digital Library
A Strong-Lens Survey in AEGIS: the influence of large scalestructure (open access)

A Strong-Lens Survey in AEGIS: the influence of large scalestructure

We report on the results of a visual search for galaxy-scale strong gravitational lenses over 650 arcmin{sup 2} of HST/ACS (F606W and F814W) imaging in the DEEP2-Extended Groth Strip (EGS). In addition to a previously-known Einstein Cross also found by our search (the 'Cross', HSTJ141735+52264, z{sub lens} = 0.8106, z{sub source} = 3.40), we identify two new strong galaxy-galaxy lenses with multiple extended arcs. The first, HSTJ141820+52361 (the 'Dewdrop'; z{sub lens} = 0.5798), lenses two distinct extended sources into two pairs of arcs (z{sub source} = 0.9818), while the second, HSTJ141833+52435 (the 'Anchor'; z{sub lens} = 0.4625), produces a single pair of arcs (z{sub lens} not yet known). Four less convincing arc/counter-arc and two-image lens candidates are also found and presented for completeness. Lenses are found in a both underdense and overdense local environments, as characterized by a robust measure, 1+{delta}{sub 3}, a normalized density that uses the distance to the third nearest neighbor. All three definite lenses are fit reasonably well by simple singular isothermal ellipsoid models including external shear, giving {chi}{sub {nu}}{sup 2} values close to unity. These shears are much greater than those implied by a simple consideration of the three-dimensional convergence and shear from galaxies along …
Date: October 13, 2006
Creator: Moustakas, Leonidas A.; Marshall, Phil; Newman, Jeffrey A.; Coil,Alison L.; Cooper, Michael C.; Davis, Marc et al.
Object Type: Article
System: The UNT Digital Library