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Evolution of the Surface Science of Catalysis from Single Crystals to Metal Nanoparticles under Pressure

Description: Vacuum studies of metal single crystal surfaces using electron and molecular beam scattering revealed that the surface atoms relocate when the surface is clean (reconstruction) and when it is covered by adsorbates (adsorbate induced restructuring). It was also discovered that atomic steps and other low coordination surface sites are active for breaking chemical bonds (H-H, O=O, C-H, C=O and C-C) with high reaction probability. Investigations at high reactant pressures using sum frequency genera… more
Date: March 6, 2008
Creator: Somorjai, Gabor A. & Park, Jeong Y.
Partner: UNT Libraries Government Documents Department
open access

New experimental capabilities and theoretical insights of high pressure compression waves

Description: Currently there are three platforms that offer quasi-isentropic compression or ramp-wave compression (RWC): light-gas gun, magnetic flux (Z-pinch), and laser. We focus here on the light-gas gun technique and on some current theoretical insights from experimental data. A gradient impedance through the length of the impactor provides the pressure pulse upon impactor to the subject material. Applications and results are given concerning high-pressure strength and liquid to solid, phase transition … more
Date: July 20, 2007
Creator: Orlikowski, D.; Nguyen, J.; Patterson, J. R.; Minich, R.; Martin, L. P. & Holmes, N.
Partner: UNT Libraries Government Documents Department
open access

How to Calculate Colourful Cross Sections Efficiently

Description: Different methods for the calculation of cross sections with many QCD particles are compared. To this end, CSW vertex rules, Berends-Giele recursion and Feynman-diagram based techniques are implemented as well as various methods for the treatment of colours and phase space integration. We find that typically there is only a small window of jet multiplicities, where the CSW technique has efficiencies comparable or better than both of the other two methods.
Date: September 3, 2008
Creator: Gleisberg, Tanju; Hoeche, Stefan & Krauss, Frank
Partner: UNT Libraries Government Documents Department
open access

Technical Risk Rating of DOE Environmental Projects - 9153

Description: The U.S. Department of Energy's Office of Environmental Management (DOE-EM) was established to achieve the safe and compliant disposition of legacy wastes and facilities from defense nuclear applications. The scope of work is diverse, with projects ranging from single acquisitions to collections of projects and operations that span several decades and costs from hundreds of millions to billions US$. The need to be able to manage and understand the technical risks from the project to senior mana… more
Date: February 11, 2009
Creator: Cercy, Michael; Fayfich, Ronald & Schneider, Steven
Partner: UNT Libraries Government Documents Department
open access

INTEGRAL BENCHMARKS AVAILABLE THROUGH THE INTERNATIONAL REACTOR PHYSICS EXPERIMENT EVALUATION PROJECT AND THE INTERNATIONAL CRITICALITY SAFETY BENCHMARK EVALUATION PROJECT

Description: Interest in high-quality integral benchmark data is increasing as efforts to quantify and reduce calculational uncertainties accelerate to meet the demands of next generation reactor and advanced fuel cycle concepts. The International Reactor Physics Experiment Evaluation Project (IRPhEP) and the International Criticality Safety Benchmark Evaluation Project (ICSBEP) continue to expand their efforts and broaden their scope to identify, evaluate, and provide integral benchmark data for method and… more
Date: September 1, 2008
Creator: Briggs, J. Blair; Scott, Lori; Sartori, Enrico & Rugama, Yolanda
Partner: UNT Libraries Government Documents Department
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High Penetration, Grid Connected Photovoltaic Technology Codes and Standards: Preprint

Description: This paper reports the interim status in identifying and reviewing photovoltaic (PV) codes and standards (C&S) and related electrical activities for grid-connected, high-penetration PV systems with a focus on U.S. electric utility distribution grid interconnection.
Date: May 1, 2008
Creator: Basso, T. S.
Partner: UNT Libraries Government Documents Department
open access

Progress with Tevatron Electron Lenses

Description: No Description Available.
Date: September 13, 2007
Creator: Kamerdzhiev, V.; Alexahin, Y.; Kuznetsov, G. F.; Shiltsev, V. D. & Zhang, X.
Partner: UNT Libraries Government Documents Department
open access

Direct Assay of Filter Media following DEOX Testing

Description: The direct assay of filter media by gamma spectrometry following DEOX testing has distinct advantages over analytical chemistry. Prior to using gamma spectrometry for the quantification of cesium (Cs-137), a calibration must be established with known sources since gamma spectrometry yields relative results. Quantitative analytical chemistry, in particular ICP-MS, has been performed on the filter media for comparison to the gamma spectrometry data. The correlation of gamma spectrometry to ICP-MS… more
Date: September 1, 2007
Creator: Lind, R. P.; Giglio, J. J.; Cummings, D. G.; Huntley, M. W.; Morgan, C. D.; Bateman, K. J. et al.
Partner: UNT Libraries Government Documents Department
open access

Use of microphysical relationships to discern growth/decay mechanisms of cloud droplets with focus on Z-LWC relationships.

Description: Cloud droplet size distributions hence the key microphysical quantities (e.g., radar reflectivity, droplet concentration, liquid water content, relative dispersion, and mean-volume radius) are determined by different physical mechanisms, including pre-cloud aerosols as CCNs, cloud updraft, and various turbulent entrainment-mixing processes. Therefore, different relationships among these microphysical properties are expected in response to these various mechanisms. The effect of turbulent entrai… more
Date: May 1, 2008
Creator: Liu, Y.; Daum, P. H.; Yum, S. S. & Wang, J.
Partner: UNT Libraries Government Documents Department
open access

Stochastic Transport Modeling of Resonant Magnetic Perturbations in DIII-D

Description: Three-dimensional two-fluid simulations of heat transport due to resonant magnetic perturbations of tokamaks have been computed by coupling the TRIP3D field line tracing code to the E3D edge transport code. The predicted electron temperature contours follow the new separatrix represented by the perturbed invariant manifold structure of the X-point in qualitative agreement with X-point TV observations. However, preliminary modeling predicts that the resulting stochastic heat transport is greater… more
Date: June 1, 2006
Creator: Joseph, I.; Moyer, R. A.; Evans, T. E.; Schaffer, M. J.; Runov, A. M.; Schneider, R. et al.
Partner: UNT Libraries Government Documents Department
open access

Theory and Fluid Simulations of Boundary Plasma Fluctuations

Description: 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 us… more
Date: January 9, 2007
Creator: Cohen, R. H.; LaBombard, B.; LoDestro, L. L.; Rognlien, T. D.; Ryutov, D. D.; Terry, J. L. et al.
Partner: UNT Libraries Government Documents Department
open access

Computational Science Research in Support of Petascale Electromagnetic Modeling

Description: Computational science research components were vital parts of the SciDAC-1 accelerator project and are continuing to play a critical role in newly-funded SciDAC-2 accelerator project, the Community Petascale Project for Accelerator Science and Simulation (ComPASS). Recent advances and achievements in the area of computational science research in support of petascale electromagnetic modeling for accelerator design analysis are presented, which include shape determination of superconducting RF ca… more
Date: June 20, 2008
Creator: Lee, L.; Akcelik, V.; Ge, L.; Chen, S.; Schussman, G.; Candel, A. et al.
Partner: UNT Libraries Government Documents Department
open access

Coherent neutrino-nucleus scattering and the MINERvA experiment

Description: In this paper we describe the capabilities of the MINERvA experiment for the measurement of neutrino-nucleus coherent scattering.
Date: January 1, 2007
Creator: Gallagher, H.; U., /Tufts; Harris, Deborah & /Fermilab
Partner: UNT Libraries Government Documents Department
open access

Measurement of Resonance Parameters of Orbitally Excited Narrow B^0 Mesons

Description: The authors report a measurement of resonance parameters of the orbitally excited (L = 1) narrow B{sup 0} mesons in decays to B{sup (*)+}{pi}{sup -} using 1.7 fb{sup -1} of data collected by the CDF II detector at the Fermilab Tevatron. The mass and width of the B*{sub 2}{sup 0} state are measured to be m(B*{sub 2}{sup 0}) = 5740.2{sub -1.8}{sup +1.7}(stat.){sub -0.8}{sup +0.9}(syst.) MeV/c{sup 2} and {Lambda}(B*{sub 2}{sup 0}) = 22.7{sub -3.2}{sup +3.8}(stat.){sub -10.2}{sup +3.2}(syst.) MeV/c… more
Date: September 1, 2008
Creator: Aaltonen, : T.
Partner: UNT Libraries Government Documents Department
open access

Adapting Existing Spatial Data Sets to New Uses: An Example from Energy Modeling

Description: Energy modeling and analysis often relies on data collected for other purposes such as census counts, atmospheric and air quality observations, and economic projections. These data are available at various spatial and temporal scales, which may be different from those needed by the energy modeling community. If the translation from the original format to the format required by the energy researcher is incorrect, then resulting models can produce misleading conclusions. This is of increasing imp… more
Date: June 23, 2006
Creator: Johanesson, G; Stewart, J S; Barr, C; Sabeff, L B; George, R; Heimiller, D et al.
Partner: UNT Libraries Government Documents Department
open access

Breaking the Curse of Cardinality on Bitmap Indexes

Description: Bitmap indexes are known to be efficient for ad-hoc range queries that are common in data warehousing and scientific applications. However, they suffer from the curse of cardinality, that is, their efficiency deteriorates as attribute cardinalities increase. A number of strategies have been proposed, but none of them addresses the problem adequately. In this paper, we propose a novel binned bitmap index that greatly reduces the cost to answer queries, and therefore breaks the curse of cardinali… more
Date: April 4, 2008
Creator: Wu, Kesheng; Wu, Kesheng; Stockinger, Kurt & Shoshani, Arie
Partner: UNT Libraries Government Documents Department
open access

Surface species formed by the adsorption and dissociation of water molecules on Ru(0001) surface containing a small coverage of carbon atoms studied by scanning tunneling microscopy

Description: The adsorption and dissociation of water on a Ru(0001) surface containing a small amount ({le} 3 %) of carbon impurities was studied by scanning tunneling microscopy (STM). Various surface species are formed depending on the temperature. These include molecular H{sub 2}O, H{sub 2}O-C complexes, H, O, OH and CH. Clusters of either pure H{sub 2}O or mixed H{sub 2}O-OH species are also formed. Each of these species produces a characteristic contrast in the STM images and can be identified by exper… more
Date: April 26, 2008
Creator: UCB, Dept of Materials Science and Engineering
Partner: UNT Libraries Government Documents Department
open access

Assessing Recharge and Geological Model Uncertainty at the Climax Mine Area of the Nevada Test Site

Description: Hydrologic analyses are commonly based on a single conceptual-mathematical model. Yet hydrologic environments are open and complex, rendering them prone to multiple interpretations and mathematical descriptions. Considering conceptual model uncertainty is a critical process in hydrologic uncertainty assessment. This study assesses recharge and geologic model uncertainty for the Climax mine area of the Nevada Test Site, Nevada. Five alternative recharge models have been independently developed f… more
Date: November 8, 2007
Creator: Ye, M.; Pohlmann, K.; Chapman, J. & Pohll, G.
Partner: UNT Libraries Government Documents Department
open access

New Equalizers for Antiproton Stochastic Cooling at Fermilab

Description: In the continuous effort to improve antiproton stacking rate, a new type of equalizers has been developed and installed in antiproton accumulator. The R&D of these new equalizers is described in this paper. Equalizers are used in Fermilab antiproton stochastic cooling to compensate frequency response of the cooling system. Usually both amplitude and phase compensations are needed. However in most cases it is difficult to achieve a satisfactory compensation for both because of their interdep… more
Date: September 13, 2007
Creator: Lebedev, V. A.; Pasquinelli, R. J. & Sun, D.
Partner: UNT Libraries Government Documents Department
open access

Accurate labeling of the light-actinide O4,5 ionization edges

Description: In this short article the accurate labeling of the O4,5 edges of the light actinides is addressed. The O4 and O5 edges are both contained in what is termed the ''giant resonance'' and the smaller ''pre-peak'' that is observed is a consequence of first-order perturbation by the 5d spin-orbit interaction. Thus, the small prepeak in the actinide 5d {yields} 5f transition should not be labeled the O5 peak, but rather the {Delta}S=1 peak.
Date: August 23, 2006
Creator: Moore, K & der Laan, G v
Partner: UNT Libraries Government Documents Department
open access

Loss Factor of the PEP-II Rings

Description: An RF power balance method is used to measure the synchrotron radiation losses and the wake field losses. We present the history of the losses in the Low Energy Ring (LER) and the High Energy Ring (HER) during the last several runs of PEP-II.
Date: July 11, 2008
Creator: Novokhatski, A. & Sullivan, M.
Partner: UNT Libraries Government Documents Department
open access

Elastic electron scattering from formic acid

Description: Following our earlier study on the dynamics of low energy electron attachment to formic acid, we report the results of elastic low-energy electron collisions with formic acid. Momentum transfer and angular differential cross sections were obtained by performing fixed-nuclei calculations employing the complex Kohn variational method. We make a brief description of the technique used to account for the polar nature of this polyatomic target and compare our results with available experimental data. more
Date: July 31, 2006
Creator: Trevisan, Cynthia S.; Orel, Ann E. & Rescigno, Thomas N.
Partner: UNT Libraries Government Documents Department
open access

Compensatory Paracrine Mechanisms That Define The Urothelial Response to Injury in Partial Bladder Outlet Obstruction

Description: Diseases and conditions affecting the lower urinary tract are a leading cause of dysfunctional sexual health, incontinence, infection, and kidney failure. The growth, differentiation, and repair of the bladder's epithelial lining are regulated, in part, by fibroblast growth factor (FGF)-7 and -10 via a paracrine cascade originating in the mesenchyme (lamina propria) and targeting the receptor for FGF-7 and -10 within the transitional epithelium (urothelium). The FGF-7 gene is located at the… more
Date: June 21, 2007
Creator: Bassuk, James; Lendvay, Thomas S.; Sweet, Robert; Han, Chang-Hee; Soygur, Tarkan; Cheng, Jan-Fang et al.
Partner: UNT Libraries Government Documents Department
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