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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

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

Optimal flux patterns in cellular metabolic networks

Description: The availability of whole-cell level metabolic networks of high quality has made it possible to develop a predictive understanding of bacterial metabolism. Using the optimization framework of flux balance analysis, I investigate metabolic response and activity patterns to variations in the availability of nutrient and chemical factors such as oxygen and ammonia by simulating 30,000 random cellular environments. The distribution of reaction fluxes is heavy-tailed for the bacteria H. pylori and E… more
Date: January 20, 2007
Creator: Almaas, E
Partner: UNT Libraries Government Documents Department
open access

Scientific Application Performance on Leading Scalar and VectorSupercomputing Platforms

Description: The last decade has witnessed a rapid proliferation of superscalar cache-based microprocessors to build high-end computing (HEC) platforms, primarily because of their generality, scalability, and cost effectiveness. However, the growing gap between sustained and peak performance for full-scale scientific applications on conventional supercomputers has become a major concern in high performance computing, requiring significantly larger systems and application scalability than implied by peak per… more
Date: January 1, 2007
Creator: Oliker, Leonid; Canning, Andrew; Carter, Jonathan; Shalf, John & Ethier, Stephane
Partner: UNT Libraries Government Documents Department
open access

APTASENSORS FOR BIOSECURITY APPLICATIONS

Description: Nucleic acid aptamers have found steadily increased utility and application steadily over the last decade. In particular, aptamers have been touted as a valuable complement to and in some cases replacement for antibodies due to their structural and functional robustness as well as their ease in generation and synthesis. They are thus attractive for biosecurity applications, e.g. pathogen detection, and are especially well suited since their in vitro generation process does not require infection… more
Date: January 3, 2007
Creator: Fischer, N; Tarasow, T & Tok, J
Partner: UNT Libraries Government Documents Department
open access

Void Coalescence Processes Quantified Through Atomistic and Multiscale Simulation

Description: Simulation of ductile fracture at the atomic scale reveals many aspects of the fracture process including specific mechanisms associated with void nucleation and growth as a precursor to fracture and the plastic deformation of the material surrounding the voids and cracks. Recently we have studied void coalescence in ductile metals using large-scale atomistic and continuum simulations. Here we review that work and present some related investigations. The atomistic simulations involve three-dime… more
Date: January 12, 2007
Creator: Rudd, R E; Seppala, E T; Dupuy, L M & Belak, J
Partner: UNT Libraries Government Documents Department
open access

Lactonization and protonation of gluconic acid: a thermodynamicand kinetic study by potentiometry, nmr and esi-ms

Description: In acidic aqueous solutions, gluconate protonation is coupled with lactonization of gluconic acid. With the decrease of pC{sub H}, two lactones ({delta}/{gamma}) are sequentially formed. The {delta}-lactone forms more readily than the {gamma}-lactone. In 0.1 M gluconate solutions, if pC{sub H} is above 2.5, only the {delta}-lactone is generated. When pC{sub H} is decreased below 2.0, the formation of the {gamma}-lactone is observable although the {delta}-lactone predominates. At I = 0.1 M NaClO… more
Date: January 10, 2007
Creator: Zhang, Z.; Gibson, P.; Clark, S.B.; Tian, G.; Zanonato, P. & Rao, L.
Partner: UNT Libraries Government Documents Department
open access

Sub-diffraction-limited multilayer coatings for the 0.3-NA Micro-Exposure Tool for extreme ultraviolet lithography

Description: This manuscript discusses the multilayer coating results for the primary and secondary mirrors of the Micro Exposure Tool (MET): a 0.30-numerical aperture (NA) lithographic imaging system with 200 x 600 {micro}m{sup 2} field of view at the wafer plane, operating in the extreme ultraviolet (EUV) wavelength region. Mo/Si multilayers were deposited by DC-magnetron sputtering on large-area, curved MET camera substrates, and a velocity modulation technique was implemented to consistently achieve mul… more
Date: January 3, 2007
Creator: Soufli, R.; Hudyma, R. M.; Spiller, E.; Gullikson, E. M.; Schmidt, M. A.; Robinson, J. C. et al.
Partner: UNT Libraries Government Documents Department
open access

Steam turbine materials and corrosion

Description: Ultra supercritical (USC) power plants offer the promise of higher efficiencies and lower emissions. Current goals of the U.S. Department of Energy’s Advanced Power Systems Initiatives include coal generation at 60% efficiency, which would require steam temperatures of up to 760°C. This research examines the steamside oxidation of alloys for use in USC systems, with emphasis placed on applications in high- and intermediate-pressure turbines. The list of alloys being examined is discussed, inclu… more
Date: January 1, 2007
Creator: Holcomb, G.R. & Ziomek-Moroz, M.
Partner: UNT Libraries Government Documents Department
open access

Recovering the Elemental Composition of Comet Wild 2 Dust in Five Stardust Impact Tracks and Terminal Particles in Aerogel

Description: The elemental (non-volatile) composition of five Stardust impact tracks and terminal particles left from capture of Comet 81P/Wild 2 dust were mapped in a synchrotron x-ray scanning microprobe with full fluorescence spectra at each pixel. Because aerogel includes background levels of several elements of interest, we employ a novel 'dual threshold' approach to discriminate against background contaminants: an upper threshold, above which a spectrum contains cometary material plus aerogel and a lo… more
Date: January 4, 2007
Creator: Ishii, H. A.; Brennan, S.; Bradley, J. P.; Luening, K.; Ignatyev, K. & Pianetta, P.
Partner: UNT Libraries Government Documents Department
open access

Low-Chrome/Chrome Free Refractories for Slagging Gasifiers

Description: Gasifiers are containment vessels used to react carbon-containing materials with oxygen and water, producing syngas (CO and H2) that is used in chemical and power production. It is also a potential source of H2 in a future hydrogen economy. Air cooled slagging gasifiers are one type of gasifier, operating at temperatures from 1275-1575º C and at pressures of 400 psi or higher. They typically use coal or petroleum coke as the carbon source, materials which contain ash impurities that liquefy at … more
Date: January 1, 2007
Creator: Bennett, J.P.; Kwong, K.-S.; Powell, C.P.; Thomas, H. & Petty, A.V., Jr.
Partner: UNT Libraries Government Documents Department
open access

Environmental Stewardship: How Semiconductor Suppliers Help to Meet Energy-Efficiency Regulations and Voluntary Specifications in China

Description: Recognizing the role that semiconductor suppliers can playin meeting energy-efficiency regulations and voluntary specifications,this paper provides an overview of Chinese policies and implementingbodies; a discussion of current programs, their goals, and effectiveness;and possible steps that can be taken tomeet these energy-efficiencyrequirements while also meeting products' high performance and costgoals.
Date: January 15, 2007
Creator: Aizhen, Li; Fanara, Andrew; Fridley, David; Merriman, Louise & Ju, Jeff
Partner: UNT Libraries Government Documents Department
open access

Interactivity vs. Fairness in Networked Linux Systems

Description: In general, the Linux 2.6 scheduler can ensure fairness and provide excellent interactive performance at the same time. However, our experiments and mathematical analysis have shown that the current Linux interactivity mechanism tends to incorrectly categorize non-interactive network applications as interactive, which can lead to serious fairness or starvation issues. In the extreme, a single process can unjustifiably obtain up to 95% of the CPU! The root cause is due to the facts that: (1) net… more
Date: January 1, 2007
Creator: Wu, Wenji & Crawford, Matt
Partner: UNT Libraries Government Documents Department
open access

Mitochondrial genome sequences and comparative genomics ofPhytophthora ramorum and P. sojae

Description: The complete sequences of the mitochondrial genomes of theoomycetes of Phytophthora ramorum and P. sojae were determined during thecourse of their complete nuclear genome sequencing (Tyler, et al. 2006).Both are circular, with sizes of 39,314 bp for P. ramorum and 42,975 bpfor P. sojae. Each contains a total of 37 identifiable protein-encodinggenes, 25 or 26 tRNAs (P. sojae and P. ramorum, respectively)specifying19 amino acids, and a variable number of ORFs (7 for P. ramorum and 12for P. sojae)… more
Date: January 1, 2007
Creator: Martin, Frank N.; Douda, Bensasson; Tyler, Brett M. & Boore,Jeffrey L.
Partner: UNT Libraries Government Documents Department
open access

Relative Biological Effectiveness of HZE Fe Ions for Induction of Micro-Nuclei at Low Doses

Description: Dose-response curves for induction of micro-nuclei (MN) was measured in Chinese hamster V79 and xrs6 (Ku80-) cells and in human mammary epithelial MCF10A cells in the dose range of 0.05-1 Gy. The Chinese Hamster cells were exposed to 1 GeV/u Fe ions, 600 MeV/u Fe ions, and 300 MeV/u Fe ions (LETs of 151, 176 and 235 keV/{micro}m respectively) as well as with 320 kVp X-rays as reference. Second-order polynomials were fitted to the induction curves and the initial slopes (the alpha values) were u… more
Date: January 16, 2007
Creator: Groesser, Torsten; Chun, Eugene & Rydberg, Bjorn
Partner: UNT Libraries Government Documents Department
open access

Gryrokinetic Simulations of ETG and ITG Turbulence

Description: No Description Available.
Date: January 9, 2007
Creator: Dimits, A. M.; Nevins, W. M.; Shumaker, D. E.; Hammett, G. W.; Dannert, T.; Jenko, F. et al.
Partner: UNT Libraries Government Documents Department
open access

Bi3+ Luminescence in ABiO2Cl (A = Sr, Ba) and BaBiO2Br

Description: Trivalent bismuth luminescence is reported in three Sillenbismuth oxyhalide phases, SrBiO2Cl, BaBiO2Cl, and BaBiO2Br. Thesecompounds exhibit Bi 6s6->6 s2 emission under UV and X-ray radiation.At room temperature, BaBiO2Cl shows the most intense light emission, withspectral and decay properties similar to those found in Bi4Ge3O12 (BGO).At low temperatures, each phase show an increase in the photoluminescenceintensities and a narrowing of the emission peaks. In contrast to thetemperature dependen… more
Date: January 18, 2007
Creator: Porter-Chapman, Yetta D.; Bourret-Courchesne, Edith E. & Derenzo,Stephen E.
Partner: UNT Libraries Government Documents Department
open access

Empirical evidence for a recent slowdown in irrigation-induced cooling

Description: Understanding the influence of past land use changes on climate is needed to improve regional projections of future climate change and inform debates about the tradeoffs associated with land use decisions. The effects of rapid expansion of irrigated area in the 20th century has remained unclear relative to other land use changes, such as urbanization, that affected a similar total land area. Using spatial and temporal variations in temperature and irrigation extent observed in California, we sh… more
Date: January 19, 2007
Creator: Bonfils, C & Lobell, D
Partner: UNT Libraries Government Documents Department
open access

Use of MCNPX for Alpha Spectrometry Simulations of a Continuous Air Monitor

Description: The purpose of this study was to determine if the alpha energy spectrum in a Passive Implanted Planar Silicon (PIPS) detector, as modeled by MCNPX [1], can be used to design a radon stripping algorithm for a continuous air monitor (CAM). This stripping algorithm would be employed to discriminate naturally occurring radioisotopes from the anthropogenic for nuclear safety -related applications. It is hoped that using an algorithm based on MCNPX simulations, the CAM will not be prone to false alar… more
Date: January 1, 2007
Creator: Robert Hayes, Craig Marianno
Partner: UNT Libraries Government Documents Department
open access

A cell nanoinjector based on carbon nanotubes

Description: Technologies for introducing molecules into living cells are vital for probing the physical properties and biochemical interactions that govern the cell's behavior. Here we report the development of a nanoscale cell injection system-termed the nanoinjector-that uses carbon nanotubes to deliver cargo into cells. A single multi-walled carbon nanotube attached to an atomic force microscope tip was functionalized with cargo via a disulfide-based linker. Penetration of cell membranes with this 'nano… more
Date: January 30, 2007
Creator: Chen, Xing; Kis, Andras; Zettl, Alex & Bertozzi, Carolyn R.
Partner: UNT Libraries Government Documents Department
open access

Characterization of a mixed salt of 1-hydroxy-pyridin-2-one Pu(IV)complexes

Description: Most expert analyses of the projected world energy needs show utilization of nuclear energy will be essential for the next few decades, and hence the need to support this technology grows. But as one measure of the supporting science base of this field, as of December 2006, only 25 Pu containing structures were in the Cambridge Structural Database, as compared to 21,807 for Fe. A comparison of the rate of addition to this knowledge base reveals that approximately 500 Fe structures are registere… more
Date: January 9, 2007
Creator: Gorden, Anne E.V.; Xu, Jide; Szigethy, Geza; Oliver, Allen; Shuh,David K. & Raymond, Kenneth N.
Partner: UNT Libraries Government Documents Department
open access

The morphologies of breast cancer cell lines in three-dimensionalassays correlate with their profiles of gene expression

Description: 3D cell cultures are rapidly becoming the method of choice for the physiologically relevant modeling of many aspects of non-malignant and malignant cell behavior ex vivo. Nevertheless, only a limited number of distinct cell types have been evaluated in this assay to date. Here we report the first large scale comparison of the transcriptional profiles and 3D cell culture phenotypes of a substantial panel of human breast cancer cell lines. Each cell line adopts a colony morphology of one of four … more
Date: January 31, 2007
Creator: Kenny, Paraic A.; Lee, Genee Y.; Myers, Connie A.; Neve, RichardM.; Semeiks, Jeremy R.; Spellman, Paul T. et al.
Partner: UNT Libraries Government Documents Department
open access

Optimal Technology Selection and Operation of Microgrids inCommercial Buildings

Description: The deployment of small (<1-2 MW) clusters of generators,heat and electrical storage, efficiency investments, and combined heatand power (CHP) applications (particularly involving heat activatedcooling) in commercial buildings promises significant benefits but posesmany technical and financial challenges, both in system choice and itsoperation; if successful, such systems may be precursors to widespreadmicrogrid deployment. The presented optimization approach to choosingsuch systems and their o… more
Date: January 15, 2007
Creator: Marnay, Chris; Venkataramanan, Giri; Stadler, Michael; Siddiqui,Afzal; Firestone, Ryan & Chandran, Bala
Partner: UNT Libraries Government Documents Department
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