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An Alternative Model for Electron Correlation in Pu

Description: Using a density functional theory based approach that treats the 5f electrons relativistically, a Pu electronic structure with zero net magnetic moment is obtained, where the 5f orbital and 5f spin moments cancel each other. By combining the spin and orbital specific densities of states with state, spin and polarization specific transition moments, it is possible to reconstruct the experimentally observed photoemission spectra from Pu. Extrapolating to a spin-resolving Fano configuration, it is… more
Date: October 23, 2007
Creator: Yu, S.; Tobin, J. & Soderlind, P.
Partner: UNT Libraries Government Documents Department
open access

SALT FOG TEST OF SAM2X5 COATED STAINLESS STEEL CYLINDER

Description: A salt fog test of an iron-based amorphous metal, SAM2X5, coated Type 316L stainless steel (SS316L) cylinder was made. The cylinder was 30-inch diameter by 88-inch long, and 3/8-inch thick. One end was welded shut with a SS316L end cap before coating. The body of the cylinder and the end cap were both coated. The cylinder was coated with SAM2X5 by the HVOF thermal spray process. The coating thickness was 0.015-inch to 0.019-inch thick. The cylinder was tested in a horizontal position. Also incl… more
Date: April 23, 2007
Creator: Aprigliano, L F; Rebak, R B; Choi, J; Lian, T & Day, S D
Partner: UNT Libraries Government Documents Department
open access

Genus Oblivious Cross Parameterization: Robust Topological Management of Inter-surface Maps

Description: We consider the problem of generating a map between two triangulated meshes, M and M{prime}, with arbitrary and possibly differing genus. This problem has rarely been tackled in its generality. Early schemes considered only topological spheres. Recent algorithms allow inputs with an arbitrary number of tunnels but require M and M{prime} to have equal genus, mapping tunnel to tunnel. Other schemes which allow more general inputs are not guaranteed to work and the authors do not provide a charact… more
Date: October 23, 2007
Creator: Bennett, J C; Pascucci, V & Joy, K I
Partner: UNT Libraries Government Documents Department
open access

Digital Frequency Domain Multiplexer for mm-Wavelength Telescopes

Description: An FPGA based digital signal processing (DSP) system for biasing and reading out multiplexed bolometric detectors for mm-wavelength telescopes is presented. This readout system is being deployed for balloon-borne and ground based cosmology experiments with the primary goal of measuring the signature of inflation with the Cosmic Microwave Background Radiation. The system consists of analog superconducting electronics running at 250 mK and 4 K, coupled to digital room temperature backend electron… more
Date: July 23, 2007
Creator: Spieler, Helmuth G; Dobbs, Matt; Bissonnette, Eric & Spieler, Helmuth G.
Partner: UNT Libraries Government Documents Department
open access

Exact de Rham Sequences of Spaces Defined on Macro-elements in Two and Three Spatial Dimensions

Description: This paper proposes new finite element spaces that can be constructed for agglomerates of standard elements that have certain regular structure. The main requirement is that the agglomerates share faces that have closed boundaries composed of 1-d edges. The spaces resulting from the agglomerated elements are subspaces of the original de Rham sequence of H{sup 1}-conforming, H(curl) conforming, H(div) conforming and piecewise constant spaces associated with an unstructured 'fine' mesh. The proce… more
Date: July 23, 2007
Creator: Pasciak, J. & Vassilevski, P.
Partner: UNT Libraries Government Documents Department
open access

Production of Neutrals and Their and Effects on the Ion Chargestates in Cathodic Vacuum Arc Plasmas

Description: Cathodic arc plasmas are considered fully ionized and theycontain multiply charged ions, yet, gaseous and metal neutrals can bepresent. It is shown that they can cause a significant reduction of theion charge states as measured far from the cathode spots. Several cathodematerials were used to study the evolution the mean ion charge state as afunction of time after arc ignition. The type of cathode material, arccurrent amplitude, intentionally increased background gas, additionalsurfaces placed … more
Date: May 23, 2007
Creator: Anders, Andre; Oks, Efim M. & Yushkov, Georgy Yu.
Partner: UNT Libraries Government Documents Department
open access

Landscape predictions from cosmological vacuum selection

Description: In Bousso-Polchinski models with hundreds of fluxes, we compute the effects of cosmological dynamics on the probability distribution of landscape vacua. Starting from generic initial conditions, we find that most fluxes are dynamically driven into a different and much narrower range of values than expected from landscape statistics alone. Hence, cosmological evolution will access only a tiny fraction of the vacua with small cosmological constant. This leads to a host of sharp predictions. Unlik… more
Date: April 23, 2007
Creator: Bousso, Raphael; Bousso, Raphael & Yang, Sheng
Partner: UNT Libraries Government Documents Department
open access

Vlt and Acs Observations of RDCS J1252.9-2927: Dynamical Structure and Galaxy Populations in a Massive Cluster at Z=1.237*

Description: We present results from an extensive spectroscopic survey, carried out with FORS on the ESO Very Large Telescope, and from an extensive multi-wavelength imaging data set from the Advanced Camera for Surveys and ground based facilities of the cluster of galaxies RDCS J1252.9-2927. We have spectroscopically confirmed 38 cluster members in the redshift range 1.22 < z < 1.25. The distribution in velocity of these spectroscopic members yields a cluster median redshift of z = 1.237 and a rest-f… more
Date: March 23, 2007
Creator: Demarco, R.; Rosati, P.; Lidman, C.; Girardi, M.; Nonino, M.; Rettura, A. et al.
Partner: UNT Libraries Government Documents Department
open access

Final optics damage inspection (FODI) for the National Ignition Facility

Description: The National Ignition Facility (NIF) at the Lawrence Livermore National Laboratory (LLNL) will routinely fire high energy shots (approaching 10 kJ per beamline) through the final optics, located on the target chamber. After a high fluence shot, exceeding 4J/cm2 at 351 nm wavelength, the final optics will be inspected for laser-induced damage. The FODI (Final Optics Damage Inspection) system has been developed for this purpose, with requirements to detect laser-induced damage initiation and to t… more
Date: October 23, 2007
Creator: Conder, A.; Alger, T.; Azevedo, S.; Chang, J.; Glenn, S.; Kegelmeyer, L. et al.
Partner: UNT Libraries Government Documents Department
open access

Active Creation of Instrinsically Localized Vibrations in Uranium Using X-Ray and Neutron Scattering

Description: In real materials, nonlinear forces cause the frequencies of vibrating atoms to depend on amplitude. As a consequence, a large-amplitude fluctuation on the scale of the atom spacing can develop a frequency that does not resonate with the normal modes, causing energy to become trapped in an intrinsically localized mode (ILM)--also called 'discrete breather' or 'lattice soliton'. As temperature is increased, entropy is expected to stabilize increased concentrations of these random hotspots. This … more
Date: August 23, 2007
Creator: Manley, M.; Alatas, A.; Trouw, F.; Hults, W.; Leu, B.; Lynn, J. et al.
Partner: UNT Libraries Government Documents Department
open access

Production of a sterile species: Quantum kinetics

Description: Production of a sterile species is studied within an effective model of active-sterile neutrino mixing in a medium in thermal equilibrium. The quantum kinetic equations for the distribution functions and coherences are obtained from two independent methods: the effective action and the quantum master equation. The decoherence time scale for active-sterile oscillations is tau(dec)=2/Gamma(aa), but the evolution of the distribution functions is determined by the two different time scales associat… more
Date: April 23, 2007
Creator: Ho, Chiu Man; Boyanovsky, D. & Ho, C.M.
Partner: UNT Libraries Government Documents Department
open access

Enhancing Scalability of Sparse Direct Methods

Description: TOPS is providing high-performance, scalable sparse direct solvers, which have had significant impacts on the SciDAC applications, including fusion simulation (CEMM), accelerator modeling (COMPASS), as well as many other mission-critical applications in DOE and elsewhere. Our recent developments have been focusing on new techniques to overcome scalability bottleneck of direct methods, in both time and memory. These include parallelizing symbolic analysis phase and developing linear-complexity s… more
Date: July 23, 2007
Creator: Li, Xiaoye S.; Demmel, James; Grigori, Laura; Gu, Ming; Xia,Jianlin; Jardin, Steve et al.
Partner: UNT Libraries Government Documents Department
open access

3D Magnetotelluic characterization of the Coso GeothermalField

Description: Electrical resistivity may contribute to progress inunderstanding geothermal systems by imaging the geometry, bounds andcontrolling structures in existing production, and thereby perhapssuggesting new areas for field expansion. To these ends, a dense grid ofmagnetotelluric (MT) stations plus a single line of contiguous bipolearray profiling has been acquired over the east flank of the Cosogeothermal system. Acquiring good quality MT data in producing geothermalsystems is a challenge due to prod… more
Date: April 23, 2007
Creator: Newman, Gregory A.; Hoversten, G. Michael; Wannamaker, Philip E. & Gasperikova, Erika
Partner: UNT Libraries Government Documents Department
open access

PNNL: A Supervised Maximum Entropy Approach to Word Sense Disambiguation

Description: In this paper, we described the PNNL Word Sense Disambiguation system as applied to the English All-Word task in Se-mEval 2007. We use a supervised learning approach, employing a large number of features and using Information Gain for dimension reduction. Our Maximum Entropy approach combined with a rich set of features produced results that are significantly better than baseline and are the highest F-score for the fined-grained English All-Words subtask.
Date: June 23, 2007
Creator: Tratz, Stephen C.; Sanfilippo, Antonio P.; Gregory, Michelle L.; Chappell, Alan R.; Posse, Christian & Whitney, Paul D.
Partner: UNT Libraries Government Documents Department
open access

Quantifying the effects of three-dimensional subsurface heterogeneity on Hortonian runoff processes using a fully-coupled numerical, stochastic approach.

Description: The impact of three-dimensional subsurface heterogeneity on hillslope runoff generated by excess infiltration (so called Hortonian runoff) is examined. A fully-coupled, parallel subsurface overland flow model is used to simulate runoff from an idealized hillslope. Ensembles of correlated, Gaussian random fields of saturated hydraulic conductivity are used to create uncertainty and variability (i.e. structure) due to subsurface heterogeneity. A large number of cases are simulated in a parametric… more
Date: August 23, 2007
Creator: Maxwell, R M & Kollet, S J
Partner: UNT Libraries Government Documents Department
open access

Formation, Stability, and Mobility of One-Dimensional Lipid Bilayer on High Curvature Substrates

Description: Curved lipid membranes are ubiquitous in living systems and play an important role in many biological processes. To understand how curvature and lipid composition affect membrane formation and fluidity we have assembled and studied mixed 1,2-Dioleoyl-sn-Glycero-3-Phosphocholine (DOPC) and 1,2-Dioleoyl-sn-Glycero-3-Phosphoethanolamine (DOPE) supported lipid bilayers on amorphous silicon nanowires with controlled diameters ranging from 20 nm to 200 nm. Addition of cone-shaped DOPE molecules to cy… more
Date: March 23, 2007
Creator: Huang, J.; Martinez, J.; Artyukhin, A.; Sirbuly, D.; Wang, Y.; Ju, J. W. et al.
Partner: UNT Libraries Government Documents Department
open access

Ovarian carcinomas with genetic and epigenetic BRCA1 loss havedistinct molecular abnormalities

Description: Subclassification of ovarian carcinomas can be used to guide treatment and determine prognosis. Germline and somatic mutations, loss of heterozygosity (LOH), and epigenetic events such as promoter hypermethylation can lead to decreased expression of BRCA1/2 in ovarian cancers. The mechanism of BRCA1/2 loss is a potential method of subclassifying high grade serous carcinomas. A consecutive series of 49 ovarian cancers was assessed for mutations status of BRCA1 and BRCA2, LOH at the BRCA1 and BRC… more
Date: July 23, 2007
Creator: Press, Joshua Z.; De Luca, Alessandro; Boyd, Niki; Young, Sean; Troussard, Armelle; Ridge, Yolanda et al.
Partner: UNT Libraries Government Documents Department
open access

Results from an International Simulation Study on Coupled Thermal,Hydrological, and Mechanical (THM) Processes near Geological NuclearWaste Repositories

Description: As part of the ongoing international DECOVALEX project, four research teams used five different models to simulate coupled thermal, hydrological, and mechanical (THM) processes near waste emplacement drifts of geological nuclear waste repositories. The simulations were conducted for two generic repository types, one with open and the other with back-filled repository drifts, under higher and lower postclosure temperatures, respectively. In the completed first model inception phase of the projec… more
Date: October 23, 2007
Creator: Rutqvist, Jonny; Rutqvist, J.; Barr, D.; Birkholzer, J.T.; Chijimatsu, M.; Kolditz, O. et al.
Partner: UNT Libraries Government Documents Department
open access

Evidence for Distinct Components of the Galactic Stellar Halo from 838 RR Lyrae Stars Discovered in the LONEOS-I Survey

Description: We present 838 ab-type RR Lyrae stars from the Lowell Observatory Near Earth Objects Survey Phase I (LONEOS-I). These objects cover 1430 deg{sup 2} and span distances ranging from 3-30kpc from the Galactic Center. Object selection is based on phased, photometric data with 28-50 epochs. We use this large sample to explore the bulk properties of the stellar halo, including the spatial distribution. The period-amplitude distribution of this sample shows that the majority of these RR Lyrae stars re… more
Date: February 23, 2007
Creator: Miceli, A; Rest, A; Stubbs, C W; Hawley, S L; Cook, K H; Magnier, E A et al.
Partner: UNT Libraries Government Documents Department
open access

Effect of solution saturation state and temperature on diopside dissolution

Description: Steady-state dissolution rates of diopside are measured as a function of solution saturation state using a titanium flow-through reactor at pH 7.5 and temperature ranging from 125 to 175 C. Diopside dissolved stoichiometrically under all experimental conditions and rates were not dependent on sample history. At each temperature, rates continuously decreased by two orders of magnitude as equilibrium was approached and did not exhibit a dissolution plateau of constant rates at high degrees of und… more
Date: March 23, 2007
Creator: Dixit, S & Carroll, S A
Partner: UNT Libraries Government Documents Department
open access

Alignment strategy for the ATLAS tracker

Description: The ATLAS experiment is a multi-purpose particle detector that will study high-energy particle collisions produced by the Large Hadron Collider. For the reconstruction of charged particles, and their production and their decay vertices, ATLAS is equipped with a sophisticated tracking system, unprecedented in size and complexity. Full exploitation of both the Inner Detector and the muon spectrometer requires an accurate alignment. The challenge of aligning the ATLAS tracking devices is discussed… more
Date: September 23, 2007
Creator: ATLAS & Golling, T.
Partner: UNT Libraries Government Documents Department
open access

Dynamic Diamond Anvil Cell (dDAC): A novel device for studying the dynamic-pressure properties of materials

Description: We have developed a unique device, a dynamic diamond anvil cell (dDAC), which repetitively applies a time-dependent load/pressure profile to a sample. This capability allows studies of the kinetics of phase transitions and metastable phases at compression (strain) rates of up to 500 GPa/sec ({approx}0.16 s{sup -1} for a metal). Our approach adapts electromechanical piezoelectric actuators to a conventional diamond anvil cell design, which enables precise specification and control of a time-depe… more
Date: February 23, 2007
Creator: Evans, W. J.; Yoo, C.; Lee, G. W.; Cynn, H.; Lipp, M. J. & Visbeck, K.
Partner: UNT Libraries Government Documents Department
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