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Facilities projects performance measurement system. [Fuels and Materials Examination Facility (EMEF); Fusion Material Irradiation Test (FMIT) facility] (open access)

Facilities projects performance measurement system. [Fuels and Materials Examination Facility (EMEF); Fusion Material Irradiation Test (FMIT) facility]

The two DOE-owned facilities at Hanford, the Fuels and Materials Examination Facility (FMEF), and the Fusion Materials Irradiation Test Facility (FMIT), are described. The performance measurement systems used at these two facilities are next described. (DLC)
Date: October 9, 1979
Creator: Erben, J.F.
System: The UNT Digital Library
Vacuum system for the Tandem Mirror Experiment (open access)

Vacuum system for the Tandem Mirror Experiment

This paper is a sequel to the one prepared by Atkinson, et al., in which the authors described the vacuum system of Lawrence Livermore Laboratory's Tandem Mirror Experiment (TMX). We discuss here the final configuration, liquid nitrogen (LN/sub 2/) supply, and operation of the complete TMX vacuum system. The assembled vacuum system consists of two plug tanks with a volume of approximately 60 m/sup 3/ each and a center cell tank with a volume of approximately 10 m/sup 3/. In each plug tank there are 145 m/sup 2/ of titanium-gettered, LN/sub 2/-filled panels, which allow a pumping speed calculated to be 5 x 10/sup 7/ l/s for a period of 50 ms. The system maintains an operating pressure in the plasma chamber on the order of 10/sup -6/ Torr while 24 neutral-beam injectors are introducing 700 Torr l/s of hydrogen into the vacuum chamber.
Date: November 9, 1979
Creator: Richardson, M. J.; Atkinson, D. P. & Calderon, M. O.
System: The UNT Digital Library
The History Engine: Doing History with Digital Tools (open access)

The History Engine: Doing History with Digital Tools

Article on the History Engine Project, an online archive consisting of thousands of narratives written and contributed by undergraduates.
Date: September 9, 2009
Creator: Nelson, Robert K.; Nesbit, Scott & Torget, Andrew J., 1978-
System: The UNT Digital Library
Genomic and Co-expression Analyses Predict Multiple Genes Involved in Triterpene Saponin Biosynthesis in Medicago truncatula (open access)

Genomic and Co-expression Analyses Predict Multiple Genes Involved in Triterpene Saponin Biosynthesis in Medicago truncatula

Article discusses genomic and coexpression analyses predicting multiple genes involved in triterpene saponin biosynthesis in Medicago truncatula.
Date: March 9, 2010
Creator: Naoumkina, Marina A.; Modolo, Luzia V.; Huhman, David; Urbanczyk-Wochniak, Ewa; Tang, Yuhong; Sumner, Lloyd W. et al.
System: The UNT Digital Library
Theory and Fluid Simulations of Boundary Plasma Fluctuations (open access)

Theory and Fluid Simulations of Boundary Plasma Fluctuations

Theoretical and computational investigations are presented of boundary plasma microturbulence that take into account important effects of the geometry of diverted tokamaks--in particular, the effect of x-point magnetic shear and the termination of field lines on divertor plates. We first generalize our previous 'heuristic boundary condition' which describes, in a lumped model, the closure of currents in the vicinity of the x-point region to encompass three current-closure mechanisms. We then use this boundary condition to derive the dispersion relation for low-beta flute-like modes in the divertor-leg region under the combined drives of curvature, sheath impedance, and divertor tilt effects. The results indicate the possibility of strongly growing instabilities, driven by sheath boundary conditions, and localized in either the private or common flux region of the divertor leg depending on the radial tilt of divertor plates. We re-visit the issue of x-point effects on blobs, examining the transition from blobs terminated by x-point shear to blobs that extend over both the main SOL and divertor legs. We find that, for a main-SOL blob, this transition occurs without a free-acceleration period as previously thought, with x-point termination conditions applying until the blob has expanded to reach the divertor plate. We also derive …
Date: January 9, 2007
Creator: Cohen, R. H.; LaBombard, B.; LoDestro, L. L.; Rognlien, T. D.; Ryutov, D. D.; Terry, J. L. et al.
System: The UNT Digital Library
ENCAPSULATION OF PALLADIUM IN POROUS WALL HOLLOW GLASS MICROSPHERES (open access)

ENCAPSULATION OF PALLADIUM IN POROUS WALL HOLLOW GLASS MICROSPHERES

A new encapsulation method was investigated in an attempt to develop an improved palladium packing material for hydrogen isotope separation. Porous wall hollow glass microspheres (PWHGMs) were produced by using a flame former, heat treating and acid leaching. The PWHGMs were then filled with palladium salt using a soak-and-dry process. The palladium salt was reduced at high temperature to leave palladium inside the microspheres.
Date: April 9, 2008
Creator: Heung, L.; George Wicks, G. & Ray Schumacher, R.
System: The UNT Digital Library
New Results on Leptonic B Meson Decays at BaBar (open access)

New Results on Leptonic B Meson Decays at BaBar

The authors present selected new results on leptonic B meson decays from the BABAR experiment: searches for the decays B{sup 0} {yields} {ell}{sup +}{ell}{sup -}, B{sup +} {yields} {ell}{sup +}{nu} and B{sup 0} {yields} {ell}{sup +}{tau}{sup -}, and B {yields} K{nu}{bar {nu}}, where {ell} = e or {mu}. They observe no evidence for these decays and set upper limits on their branching fractions.
Date: June 9, 2008
Creator: Kim, Hojeong
System: The UNT Digital Library
SQUID-Detected MRI at 132 Microtesla with T1 Contrast Weighted at10 Microtelsa-300 mT (open access)

SQUID-Detected MRI at 132 Microtesla with T1 Contrast Weighted at10 Microtelsa-300 mT

None
Date: August 9, 2004
Creator: Lee, SeungKyun; Moessle, Michael; Myers, Whittier; Kelso, Nathan; Trabesinger, Andreas H.; Pines, Alex et al.
System: The UNT Digital Library
IDENTIFYING ISOTROPIC EVENTS USING AN IMPROVED REGIONAL MOMENT TENSOR INVERSION TECHNIQUE (open access)

IDENTIFYING ISOTROPIC EVENTS USING AN IMPROVED REGIONAL MOMENT TENSOR INVERSION TECHNIQUE

None
Date: July 9, 2007
Creator: Ford, S R; Dreger, D S & Walter, W R
System: The UNT Digital Library
SYNTHESIS OF THE FULLY PROTECTED PHOSPHORAMIDITE OF THE BENZENE-DNA ADDUCT, N2- (4-HYDROXYPHENYL)-2'-DEOXYGUANOSINE AND INCORPORATION OF THE LATER INTO DNA OLIGOMERS (open access)

SYNTHESIS OF THE FULLY PROTECTED PHOSPHORAMIDITE OF THE BENZENE-DNA ADDUCT, N2- (4-HYDROXYPHENYL)-2'-DEOXYGUANOSINE AND INCORPORATION OF THE LATER INTO DNA OLIGOMERS

N2-(4-Hydroxyphenyl)-2'-deoxyguanosine-5'-O-DMT-3'-phosphoramidite has been synthesized and used to incorporate the N2-(4-hydroxyphenyl)-2'-dG (N2-4-HOPh-dG) into DNA, using solid-state synthesis technology. The key step to obtaining the xenonucleoside is a palladium (Xantphos-chelated) catalyzed N2-arylation (Buchwald-Hartwig reaction) of a fully protected 2'-deoxyguanosine derivative by 4-isobutyryloxybromobenzene. The reaction proceeded in good yield and the adduct was converted to the required 5'-O-DMT-3'-O-phosphoramidite by standard methods. The latter was used to synthesize oligodeoxynucleotides in which the N2-4-HOPh-dG adduct was incorporated site-specifically. The oligomers were purified by reverse-phase HPLC. Enzymatic hydrolysis and HPLC analysis confirmed the presence of this adduct in the oligomers.
Date: June 9, 2008
Creator: Chenna, Ahmed; Gupta, Ramesh C.; Bonala, Radha R.; Johnson, Francis & Huang, Bo
System: The UNT Digital Library
Behavior of Repeating Earthquake Sequences in Central California and the Implications for Subsurface Fault Creep (open access)

Behavior of Repeating Earthquake Sequences in Central California and the Implications for Subsurface Fault Creep

Repeating earthquakes (REs) are sequences of events that have nearly identical waveforms and are interpreted to represent fault asperities driven to failure by loading from aseismic creep on the surrounding fault surface at depth. We investigate the occurrence of these REs along faults in central California to determine which faults exhibit creep and the spatio-temporal distribution of this creep. At the juncture of the San Andreas and southern Calaveras-Paicines faults, both faults as well as a smaller secondary fault, the Quien Sabe fault, are observed to produce REs over the observation period of March 1984-May 2005. REs in this area reflect a heterogeneous creep distribution along the fault plane with significant variations in time. Cumulative slip over the observation period at individual sequence locations is determined to range from 5.5-58.2 cm on the San Andreas fault, 4.8-14.1 cm on the southern Calaveras-Paicines fault, and 4.9-24.8 cm on the Quien Sabe fault. Creep at depth appears to mimic the behaviors seen of creep on the surface in that evidence of steady slip, triggered slip, and episodic slip phenomena are also observed in the RE sequences. For comparison, we investigate the occurrence of REs west of the San Andreas fault within the …
Date: July 9, 2007
Creator: Templeton, D C; Nadeau, R & Burgmann, R
System: The UNT Digital Library
Structure and Reactions of Carbon and Hydrogen on Ru(0001): A Scanning Tunneling Microscopy Study (open access)

Structure and Reactions of Carbon and Hydrogen on Ru(0001): A Scanning Tunneling Microscopy Study

The interaction between carbon and hydrogen atoms on a Ru(0001) surface was studied using scanning tunneling microscopy (STM), Density Functional Theory (DFT) and STM image calculations. Formation of CH species by reaction between adsorbed H and C was observed to occur readily at 100 K. When the coverage of H increased new complexes of the form CH+nH (n = 1, 2 and 3) were observed. These complexes, never observed before, might be precursors for further hydrogenation reactions. DFT analysis reveals that a considerable energy barrier exists for the CH+H {yields} CH{sub 2} reaction.
Date: September 9, 2008
Creator: Shimizu, Tomoko K.; Mugarza, Aitor; Cerda, Jorge & Salmeron, Miquel
System: The UNT Digital Library
Thermodynamic ground states of platinum metal nitrides (open access)

Thermodynamic ground states of platinum metal nitrides

We have systematically studied the thermodynamic stabilities of various phases of the nitrides of the platinum metal elements using density functional theory. We show that for the nitrides of Rh, Pd, Ir and Pt two new crystal structures, in which the metal ions occupy simple tetragonal lattice sites, have lower formation enthalpies at ambient conditions than any previously proposed structures. The region of stability can extend up to 17 GPa for PtN{sub 2}. Furthermore, we show that according to calculations using the local density approximation, these new compounds are also thermodynamically stable at ambient pressure and thus may be the ground state phases for these materials. We further discuss the fact that the local density and generalized gradient approximations predict different values of the absolute formation enthalpies as well different relative stabilities between simple tetragonal and the pyrite or marcasite structures.
Date: October 9, 2007
Creator: Aberg, D; Sadigh, B; Crowhurst, J & Goncharov, A
System: The UNT Digital Library
Light-Front Holography and QCD Hadronization at the Amplitude Level (open access)

Light-Front Holography and QCD Hadronization at the Amplitude Level

Light-front holography allows hadronic amplitudes in the AdS/QCD fifth dimension to be mapped to frame-independent light-front wavefunctions of hadrons in physical space-time, thus providing a relativistic description of hadrons at the amplitude level. The AdS coordinate z is identified with an invariant light-front coordinate {zeta} which separates the dynamics of quark and gluon binding from the kinematics of constituent spin and internal orbital angular momentum. The result is a single-variable light-front Schroedinger equation for QCD which determines the eigenspectrum and the light-front wavefunctions of hadrons for general spin and orbital angular momentum. A new method for computing the hadronization of quark and gluon jets at the amplitude level using AdS/QCD light-front wavefunctions is outlined.
Date: January 9, 2009
Creator: Brodsky, Stanley J. & de Teramond, Guy F.
System: The UNT Digital Library
Toward fully self-consistent simulation of the interaction of E-Clouds and beams with WARP-POSINST (open access)

Toward fully self-consistent simulation of the interaction of E-Clouds and beams with WARP-POSINST

To predict the evolution of electron clouds and their effect on the beam, the high energy physics community has relied so far on the complementary use of 'buildup' and 'single/multi-bunch instability' reduced descriptions. The former describes the evolution of electron clouds at a given location in the ring, or 'station', under the influence of prescribed beams and external fields [1], while the latter (sometimes also referred as the 'quasi-static' approximation [2]) follows the interaction between the beams and the electron clouds around the accelerator with prescribed initial distributions of electrons, assumed to be concentrated at a number of discrete 'stations' around the ring. Examples of single bunch instability codes include HEADTAIL [3], QuickPIC [4, 5], and PEHTS [6]. By contrast, a fully self-consistent approach, in which both the electron cloud and beam distributions evolve simultaneously under their mutual influence without any restriction on their relative motion, is required for modeling the interaction of high-intensity beams with electron clouds for heavy-ion beam-driven fusion and warm-dense matter science. This community has relied on the use of Particle-In-Cell (PIC) methods through the development and use of the WARP-POSINST code suite [1, 7, 8]. The development of novel numerical techniques (including adaptive mesh refinement, …
Date: April 9, 2012
Creator: Lawrence Livermore National Laboratory
System: The UNT Digital Library
Silver ion mediated shape control of platinum nanoparticles: Removal of silver by selective etching leads to increased catalytic activity (open access)

Silver ion mediated shape control of platinum nanoparticles: Removal of silver by selective etching leads to increased catalytic activity

A procedure has been developed for the selective etching of Ag from Pt nanoparticles of well-defined shape, resulting in the formation of elementally-pure Pt cubes, cuboctahedra, or octahedra, with a largest vertex-to-vertex distance of {approx}9.5 nm from Ag-modified Pt nanoparticles. A nitric acid etching process was applied Pt nanoparticles supported on mesoporous silica, as well as nanoparticles dispersed in aqueous solution. The characterization of the silica-supported particles by XRD, TEM, and N{sub 2} adsorption measurements demonstrated that the structure of the nanoparticles and the mesoporous support remained conserved during etching in concentrated nitric acid. Both elemental analysis and ethylene hydrogenation indicated etching of Ag is only effective when [HNO{sub 3}] {ge} 7 M; below this concentration, the removal of Ag is only {approx}10%. Ethylene hydrogenation activity increased by four orders of magnitude after the etching of Pt octahedra that contained the highest fraction of silver. High-resolution transmission electron microscopy of the unsupported particles after etching demonstrated that etching does not alter the surface structure of the Pt nanoparticles. High [HNO{sub 3}] led to the decomposition of the capping agent, polyvinylpyrollidone (PVP); infrared spectroscopy confirmed that many decomposition products were present on the surface during etching, including carbon monoxide.
Date: January 9, 2008
Creator: Grass, Michael E.; Yue, Yao; Habas, Susan E.; Rioux, Robert M.; Teall, Chelsea I. & Somorjai, G.A.
System: The UNT Digital Library
The US Support program to IAEA Safeguards - 2008 (open access)

The US Support program to IAEA Safeguards - 2008

The U.S. Support Program to IAEA Safeguards (USSP) was established in 1977 to provide technical assistance to the IAEA Department of Safeguards. Since that time the U.S. Department of State has provided funding of over $200 million and over 900 tasks have been completed by USSP contractors on behalf of the KEA. The USSP is directed by a U.S. interagency subcommittee known as the Subgroup on Safeguards Technical Support (SSTS) and is managed by the International Safeguards Project Office (ISPO) at Brookhaven National Laboratory. In recent years, the SSTS and ISPO have identified priorities to guide the process of determining which IAEA requests are aligned with US. policy and will be funded. The USSP priorities are reviewed and updated prior to the USSP Annual Review Meeting which is hosted by the International Atomic Energy Agency (IAEA) each spring in Vienna, Austria. This paper will report on the 2008 USSP priorities and be an introduction for a session which will consist of four papers on USSP priorities and four other papers related to USSP activities.
Date: June 9, 2008
Creator: Pepper,S.
System: The UNT Digital Library
Dynamic versus Static Hadronic Structure Functions (open access)

Dynamic versus Static Hadronic Structure Functions

'Static' structure functions are the probabilistic distributions computed from the square of the light-front wavefunctions of the target hadron. In contrast, the 'dynamic' structure functions measured in deep inelastic lepton-hadron scattering include the effects of rescattering associated with the Wilson line. Initial- and final-state rescattering, neglected in the parton model, can have a profound effect in QCD hard-scattering reactions, producing single-spin asymmetries, diffractive deep inelastic scattering, diffractive hard hadronic reactions, the breakdown of the Lam-Tung relation in Drell-Yan reactions, nuclear shadowing, and non-universal nuclear antishadowing|novel leading-twist physics not incorporated in the light-front wavefunctions of the target computed in isolation. I also review how 'direct' higher-twist processes--where a proton is produced in the hard subprocess itself--can explain the anomalous proton-to-pion ratio seen in high centrality heavy ion collisions.
Date: January 9, 2009
Creator: Brodsky, Stanley J.
System: The UNT Digital Library
An Extensible Open-Source Compiler Infrastructure for Testing (open access)

An Extensible Open-Source Compiler Infrastructure for Testing

Testing forms a critical part of the development process for large-scale software, and there is growing need for automated tools that can read, represent, analyze, and transform the application's source code to help carry out testing tasks. However, the support required to compile applications written in common general purpose languages is generally inaccessible to the testing research community. In this paper, we report on an extensible, open-source compiler infrastructure called ROSE, which is currently in development at Lawrence Livermore National Laboratory. ROSE specifically targets developers who wish to build source-based tools that implement customized analyses and optimizations for large-scale C, C++, and Fortran90 scientific computing applications (on the order of a million lines of code or more). However, much of this infrastructure can also be used to address problems in testing, and ROSE is by design broadly accessible to those without a formal compiler background. This paper details the interactions between testing of applications and the ways in which compiler technology can aid in the understanding of those applications. We emphasize the particular aspects of ROSE, such as support for the general analysis of whole programs, that are particularly well-suited to the testing research community and the scale of the …
Date: December 9, 2005
Creator: Quinlan, D; Ur, S & Vuduc, R
System: The UNT Digital Library
Photofragment Coincidence Imaging of Small I- (H2O)n Clusters Excited to the Charge-transfer-to-solvent State (open access)

Photofragment Coincidence Imaging of Small I- (H2O)n Clusters Excited to the Charge-transfer-to-solvent State

The photodissociation dynamics of small I{sup -}(H{sub 2}O){sub n} (n = 2-5) clusters excited to their charge-transfer-to-solvent (CTTS) states have been studied using photofragment coincidence imaging. Upon excitation to the CTTS state, two photodissociation channels were observed. The major channel ({approx}90%) is a 2-body process forming neutral I + (H{sub 2}O){sub n} photofragments, and the minor channel is a 3-body process forming I + (H{sub 2}O){sub n-1} + H{sub 2}O fragments. Both process display translational energy (P(E{sub T})) distributions peaking at E{sub T} = 0 with little available energy partitioned into translation. Clusters excited to the detachment continuum rather than to the CTTS state display the same two channels with similar P(E{sub T}) distributions. The observation of similar P(E{sub T}) distributions from the two sets of experiments suggests that in the CTTS experiments, I atom loss occurs after autodetachment of the excited (I(H{sub 2}O){sub n}{sup -})* cluster, or, less probably, that the presence of the excess electron has little effect on the departing I atom.
Date: November 9, 2005
Creator: Neumark, D. E. Szpunar, K. E. Kautzman, A. E. Faulhaber, and D. M.; Kautzman, K.E.; Faulhaber, A.E. & Faulhaber, A.E.
System: The UNT Digital Library
Gryrokinetic Simulations of ETG and ITG Turbulence (open access)

Gryrokinetic Simulations of ETG and ITG Turbulence

None
Date: January 9, 2007
Creator: Dimits, A. M.; Nevins, W. M.; Shumaker, D. E.; Hammett, G. W.; Dannert, T.; Jenko, F. et al.
System: The UNT Digital Library
Ionization By Impact Electrons in Solids: Electron Mean Free Path Fitted Over A Wide Energy Range (open access)

Ionization By Impact Electrons in Solids: Electron Mean Free Path Fitted Over A Wide Energy Range

We propose a simple formula for fitting the electron mean free paths in solids both at high and at low electron energies. The free-electron-gas approximation used for predicting electron mean free paths is no longer valid at low energies (E < 50 eV), as the band structure effects become significant at those energies. Therefore we include the results of the band structure calculations in our fit. Finally, we apply the fit to 9 elements and 2 compounds.
Date: June 9, 2005
Creator: Ziaja, B; London, R A & Hajdu, J
System: The UNT Digital Library
Accelerator mass spectrometry of actinides (open access)

Accelerator mass spectrometry of actinides

None
Date: June 9, 2005
Creator: Marchetti, A. A.; Brown, T. A.; Cox, C. C.; Hamilton, T. F. & Martinelli, R. E.
System: The UNT Digital Library
EFFECTIVE DOSIMETRIC HALF LIFE OF CESIUM 137 SOIL CONTAMINATION (open access)

EFFECTIVE DOSIMETRIC HALF LIFE OF CESIUM 137 SOIL CONTAMINATION

In the early 1960s, an area of privately-owned swamp adjacent to the US Department of Energy's Savannah River Site (SRS), known as Creek Plantation, was contaminated by site operations. Studies conducted in 1974 estimated that approximately 925 GBq of {sup 137}Cs was deposited in the swamp. Subsequently, a series of surveys--composed of 52 monitoring locations--was initiated to characterize and trend the contaminated environment. The annual, potential, maximum doses to a hypothetical hunter were estimated by conservatively using the maximum {sup 137}Cs concentrations measured in the soil. The purpose of this report is to calculate an 'effective dosimetric' half-life for {sup 137}Cs in soil (based on the maximum concentrations) and compare it to the effective environmental half-life (based on the geometric mean concentrations).
Date: January 9, 2008
Creator: Jannik, T; P Fledderman, P & Michael Paller, M
System: The UNT Digital Library