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1Surface structure of cleaved (001) USB2 single crystal surface

Description: We have achieved what we believe to be the first atomic resolution STM images for a uranium compound USb2 taken at room temperature. The a, b, and c lattice parameters in the images confirm that the tetragonal USb2crystals cleave on the (00 I) basal plane as expected. Our calculations indicate a symmetric cut between Sb planes to be the most favorable cleavage plane and U atoms to be responsible for most ofthe density of states measured by STM. Since the spacing between Sb atoms and between U a… more
Date: January 1, 2009
Creator: Chen, Shao-ping
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Partner: UNT Libraries Government Documents Department
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2008 Wind Energy Projects, Wind Powering America (Poster)

Description: The Wind Powering America program produces a poster at the end of every calendar year that depicts new U.S. wind energy projects. The 2008 poster includes the following projects: Stetson Wind Farm in Maine; Dutch Hill Wind Farm in New York; Grand Ridge Wind Energy Center in Illinois; Hooper Bay, Alaska; Forestburg, South Dakota; Elbow Creek Wind Project in Texas; Glacier Wind Farm in Montana; Wray, Colorado; Smoky Hills Wind Farm in Kansas; Forbes Park Wind Project in Massachusetts; Spanish For… more
Date: January 1, 2009
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Partner: UNT Libraries Government Documents Department
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3D design activities at Fermilab: Opportunities for physics

Description: Fermilab began exploring the technologies for vertically integrated circuits (also commonly known as 3D circuits) in 2006. These technologies include through silicon vias (TSV), circuit thinning, and bonding techniques to replace conventional bump bonds. Since then, the interest within the High Energy Physics community has grown considerably. This paper will present an overview of the activities at Fermilab over the last 3 years which have helped spark this interest.
Date: January 1, 2009
Creator: Yarema, Raymond; Deptuch, Grezgorz; Hoff, Jim; Shenai, Alpana; Trimpl, Marcel; Zimmerman, Tom et al.
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Partner: UNT Libraries Government Documents Department
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Ab-initio calculations of the hydrogen-uranium system. Part I: Surface phenomena, absorption, transport and trapping

Description: Density functional theory was applied to the initial steps of uranium hydriding: surface phenomena, absorption, bulk transport and trapping. H adsorbs exothermically to the (0 0 1) surface, yet H absorption into the bulk is endothermic, with off-center octahedral absorption having the lowest absorption energy of 0.39 eV, relative to molecular H{sub 2}. H absorption in interstitial sites causes a local softening of the bulk modulus. Diffusion of H in unstrained {alpha}-U has a barrier of 0.6 eV.… more
Date: January 1, 2009
Creator: Taylor, Christopher D & Lillard, R Scott
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Partner: UNT Libraries Government Documents Department
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Accelerating the disposition of transuranic waste from LANL - 9495

Description: Los Alamos National Laboratory (LANL) was established during World War II with a single mission -- to design and build an atomic bomb. In the 65 years since, nuclear weapons physics, design and engineering have been the Laboratory's primary and sustaining mission. Experimental and process operations -- and associated cleanout and upgrade activities -- have generated a significant inventory of transuranic (TRU) waste that is stored at LANL's Technical Area 54, Material Disposal Area G (MDA G). W… more
Date: January 1, 2009
Creator: Shepard, Mark D; Stiger, Susan G; Blankenhorn, James A; Rael, George J & Moody, David C
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Partner: UNT Libraries Government Documents Department
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Adaptive anisotropic meshing for steady convection-dominated problems

Description: Obtaining accurate solutions for convection–diffusion equations is challenging due to the presence of layers when convection dominates the diffusion. To solve this problem, we design an adaptive meshing algorithm which optimizes the alignment of anisotropic meshes with the numerical solution. Three main ingredients are used. First, the streamline upwind Petrov–Galerkin method is used to produce a stabilized solution. Second, an adapted metric tensor is computed from the approximate solution. Th… more
Date: January 1, 2009
Creator: Nguyen, Hoa; Gunzburger, Max; Ju, Lili & Burkardt, John
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Partner: UNT Libraries Government Documents Department
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Adaptive management: a paradigm for remediation of public facilities

Description: Public facility restoration planning traditionally focused on response to natural disasters and hazardous materials accidental releases. These plans now need to integrate response to terrorist actions. Therefore, plans must address a wide range of potential vulnerabilities. Similar types of broad remediation planning are needed for restoration of waste and hazardous material handling areas and facilities. There are strong similarities in damage results and remediation activities between uninten… more
Date: January 1, 2009
Creator: Janecky, David R; Whicker, Jeffrey J & Doerr, Ted B
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Partner: UNT Libraries Government Documents Department
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Advanced Fuel Cycle Economic Analysis of Symbiotic Light-Water Reactor and Fast Burner Reactor Systems

Description: The Advanced Fuel Cycle Economic Analysis of Symbiotic Light-Water Reactor and Fast Burner Reactor Systems, prepared to support the U.S. Advanced Fuel Cycle Initiative (AFCI) systems analysis, provides a technology-oriented baseline system cost comparison between the open fuel cycle and closed fuel cycle systems. The intent is to understand their overall cost trends, cost sensitivities, and trade-offs. This analysis also improves the AFCI Program’s understanding of the cost drivers that will de… more
Date: January 1, 2009
Creator: Shropshire, D. E.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Advances in Dust Detection and Removal for Tokamaks

Description: Dust diagnostics and removal techniques are vital for the safe operation of next step fusion devices such as ITER. In the tokamak environment, large particles or fi bers can fall on the electrostatic detector potentially causing a permanent short. An electrostatic dust detector developed in the laboratory is being applied to the National Spherical Torus Experiment (NSTX). We report on the development of a gas puff system that uses helium to clear such particles from the detector. Experiments at… more
Date: January 1, 2009
Creator: Campos, A. & Skinner, C. H.
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Partner: UNT Libraries Government Documents Department
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Algorithms for optimal dyadic decision trees

Description: A new algorithm for constructing optimal dyadic decision trees was recently introduced, analyzed, and shown to be very effective for low dimensional data sets. This paper enhances and extends this algorithm by: introducing an adaptive grid search for the regularization parameter that guarantees optimal solutions for all relevant trees sizes, revising the core tree-building algorithm so that its run time is substantially smaller for most regularization parameter values on the grid, and incorpora… more
Date: January 1, 2009
Creator: Hush, Don & Porter, Reid
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Partner: UNT Libraries Government Documents Department
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Analysis and algorithms for a regularized Cauchy problem arising from a non-linear elliptic PDE for seismic velocity estimation

Description: In the present work we derive and study a nonlinear elliptic PDE coming from the problem of estimation of sound speed inside the Earth. The physical setting of the PDE allows us to pose only a Cauchy problem, and hence is ill-posed. However we are still able to solve it numerically on a long enough time interval to be of practical use. We used two approaches. The first approach is a finite difference time-marching numerical scheme inspired by the Lax-Friedrichs method. The key features of this … more
Date: January 1, 2009
Creator: Cameron, M. K.; Fomel, S. B. & Sethian, J. A.
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Partner: UNT Libraries Government Documents Department
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Analysis of error floor of LDPC codes under LP decoding over the BSC

Description: We consider linear programming (LP) decoding of a fixed low-density parity-check (LDPC) code over the binary symmetric channel (BSC). The LP decoder fails when it outputs a pseudo-codeword which is not a codeword. We propose an efficient algorithm termed the instanton search algorithm (ISA) which, given a random input, generates a set of flips called the BSC-instanton and prove that: (a) the LP decoder fails for any set of flips with support vector including an instanton; (b) for any input, the… more
Date: January 1, 2009
Creator: Chertkov, Michael; Chilappagari, Shashi; Vasic, Bane & Stepanov, Mikhail
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Partner: UNT Libraries Government Documents Department
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Analysis of Godiva-IV delayed-critical and static super-prompt-critical conditions

Description: Super-prompt-critical burst experiments were conducted on the Godiva-IV assembly at Los Alamos National Laboratory from the 1960s through 2005. Detailed and simplified benchmark models have been constructed for four delayed-critical experiments and for the static phase of a super-prompt-critical burst experiment. In addition, a two-dimensional cylindrical model has been developed for the super-prompt-critical condition. Criticality calculations have been performed for all of those models with f… more
Date: January 1, 2009
Creator: Mosteller, Russell D & Goda, Joetta M
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Partner: UNT Libraries Government Documents Department
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Analytical Study of Stress State in HTS Solenoids

Description: A main challenge for high field solenoids made of in High Temperature Superconductor (HTS) is the large stress developed in the conductor. This is especially constraining for BSCCO, a brittle and strain sensitive ceramic material. To find parametric correlations useful in magnet design, analytical models can be used. A simple model is herein proposed to obtain the radial, azimuthal and axial stresses in a solenoid as a function of size, i.e. self-field, and of the engineering current density fo… more
Date: January 1, 2009
Creator: Barzi, E. & Terzini, E.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Anomalous diffusion and scaling in coupled stochastic processes

Description: Inspired by problems in biochemical kinetics, we study statistical properties of an overdamped Langevin processes with the friction coefficient depending on the state of a similar, unobserved, process. Integrating out the latter, we derive the Pocker-Planck the friction coefficient of the first depends on the state of the second. Integrating out the latter, we derive the Focker-Planck equation for the probability distribution of the former. This has the fonn of diffusion equation with time-depe… more
Date: January 1, 2009
Creator: Bel, Golan & Nemenman, Ilya
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Partner: UNT Libraries Government Documents Department
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Application of x-ray tomography to optimization of new NOx/NH3 mixed potential sensors for vehicle on-board emissions control

Description: Mixed potential sensors for the detection of hydrocarbons, NO{sub x}, and NH{sub 3} have been previously developed at Los Alamos National Laboratory (LANL). The LANL sensors have a unique design incorporating dense ceramic-pelletlmetal-wire electrodes and porous electrolytes. The performance of current-biased sensors using an yttria-stabilized zirconia (YSZ) electrolyte and platinum and La{sub 0.8}Sr{sub 0.2}CrO{sub 3} electrodes is reported. X-ray tomography has been applied to non-destructive… more
Date: January 1, 2009
Creator: Nelson, Mark A; Brosha, Eric L; Mukundan, Rangachary & Garzon, Fernando H
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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An applied study using systems engineering methods to prioritize green systems options

Description: For many years, there have been questions about the effectiveness of applying different green solutions. If you're building a home and wish to use green technologies, where do you start? While all technologies sound promising, which will perform the best over time? All this has to be considered within the cost and schedule of the project. The amount of information available on the topic can be overwhelming. We seek to examine if Systems Engineering methods can be used to help people choose and … more
Date: January 1, 2009
Creator: Lee, Sonya M & Macdonald, John M
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Partner: UNT Libraries Government Documents Department
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Approximate inference on planar graphs using loop calculus and belief progagation

Description: We introduce novel results for approximate inference on planar graphical models using the loop calculus framework. The loop calculus (Chertkov and Chernyak, 2006b) allows to express the exact partition function Z of a graphical model as a finite sum of terms that can be evaluated once the belief propagation (BP) solution is known. In general, full summation over all correction terms is intractable. We develop an algorithm for the approach presented in Chertkov et al. (2008) which represents an … more
Date: January 1, 2009
Creator: Chertkov, Michael; Gomez, Vicenc & Kappen, Hilbert
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Partner: UNT Libraries Government Documents Department
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ART CCIM Phase II-A Off-Gas System Evaluation Test Plan

Description: This test plan defines testing to be performed using the Idaho National Laboratory (INL) engineering-scale cold crucible induction melter (CCIM) test system for Phase II-A of the Advanced Remediation Technologies (ART) CCIM Project. The multi-phase ART-CCIM Project is developing a conceptual design for replacing the joule-heated melter (JHM) used to treat high level waste (HLW) in the Defense Waste Processing Facility (DWPF) at the Savannah River Site (SRS) with a cold crucible induction melter… more
Date: January 1, 2009
Creator: Soelberg, Nick & Roach, Jay
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Assessment of Supply Chain Energy Efficiency Potentials: A U.S. Case Study

Description: This paper summarizes a modeling framework that characterizes the key underlying technologies and processes that contribute to the supply chain energy use and greenhouse gas (GHG) emissions of a variety of goods and services purchased by U.S. consumers. The framework couples an input-output supply chain modeling approach with"bottom-up" fuel end use models for individual IO sectors. This fuel end use modeling detail allows energy and policy analysts to better understand the underlying… more
Date: January 1, 2009
Creator: Masanet, Eric; Kramer, Klaas Jan; Homan, Gregory; Brown, Richard & Worrell, Ernst
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Partner: UNT Libraries Government Documents Department
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Asymptotic analysis of spatial discretizations in implicit Monte Carlo

Description: We perform an asymptotic analysis of spatial discretizations in Implicit Monte Carlo (IMC). We consider two asymptotic scalings: one that represents a time step that resolves the mean-free time, and one that corresponds to a fixed, optically large time step. We show that only the latter scaling results in a valid spatial discretization of the proper diffusion equation, and thus we conclude that IMC only yields accurate solutions when using optically large spatial cells if time steps are also op… more
Date: January 1, 2009
Creator: Densmore, Jeffery D
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Partner: UNT Libraries Government Documents Department
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Audit Report on "Management Controls over the Department's Excess Weapons Inventories and Selected Sensitive Equipment used by Protective Forces"

Description: Since September 11, 2001, the Department of Energy has, on several occasions, revised its security posture based on identified threats and adversaries. These revisions in security posture have driven Departmental sites to upgrade their defensive and tactical equipment. Subsequent changes in the perceived threats have, in some cases, led to a reduction in the need for certain types of weapons, thus creating a pool of surplus equipment. These surplus weapons could potentially be used by other Dep… more
Date: January 1, 2009
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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