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Measurement of Flow Phenomena in a VHTR Lower Plenum Model

Description: Mean velocity and turbulence data that measure turbulent flow phenomena in an approximately 1:7 scale model of a region of the lower plenum of a typical prismatic gas-cooled reactor are presented as a follow-up to summaries presented at the 2006 Annual Meeting and the 2006 Winter Meeting. The experiments were designed to develop benchmark databases to support the first Standard Problem endorsed by the Generation IV International Forum to validate the heat transfer and fluid flow software that w… more
Date: June 1, 2007
Creator: Jr., Hugh M. McIlroy; McEligot, Donald M. & Pink, Robert J.
Partner: UNT Libraries Government Documents Department
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Experimental and theoretical studies of particle generation afterlaser ablation of copper with background gas at atmosphericpressure

Description: Laser ablation has proven to be an effective method for generating nanoparticles; particles are produced in the laser induced vapor plume during the cooling stage. To understand the in-situ condensation process, a series of time resolved light scattering images were recorded and analyzed. Significant changes in the condensation rate and the shape of the condensed aerosol plume were observed in two background gases, helium and argon. The primary particle shape and size distribution were measured… more
Date: May 31, 2007
Creator: Wen, Sy-Bor; Mao, Xianglei; Greif, Ralph & Russo, Richard E.
Partner: UNT Libraries Government Documents Department
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Soft Phonons in (delta)-Phase Plutonium Near the (delta)-(alpha)' Transition

Description: Plutonium and its alloys exhibit complex phase diagrams that imply anomalous lattice dynamics near phase stability boundaries. Specifically, the TA [111] phonon branch in Ga-stabilized {delta}-Pu at room temperature shows a pronounced soft mode at the zone boundary, which suggests a possible connection to the martensitic transformation from the fcc {delta}-phase to the monoclinic {alpha}{prime}-phase at low temperatures. This work is a study of the lattice dynamics of this system by x-ray therm… more
Date: September 13, 2007
Creator: Xu, R; Wong, J; Zshack, P; Hong, H & Chiang, T
Partner: UNT Libraries Government Documents Department
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Syntheses, Structure, Magnetism, and Optical Properties of Lutetium-based Interlanthanide Selenides

Description: Ln{sub 3}LuSe{sub 6} (Ln = La, Ce), {beta}-LnLuSe{sub 3} (Ln = Pr, Nd), and Ln{sub x}Lu{sub 4-x}Se{sub 6} (Ln = Sm, Gd; x = 1.82, 1.87) have been synthesized using a Sb{sub 2}Se{sub 3} flux at 1000 C. Ln{sub 3}LuSe{sub 6} (Ln = La, Ce) adopt the U{sub 3}ScS{sub 6}-type three-dimensional structure, which is constructed from two-dimensional {infinity}{sup 2} [Ln{sub 3}Se{sub 6}]{sup 3-} slabs with the gaps between these slabs filled by octahedrally coordinated Lu{sup 3+} ions. The series of {beta… more
Date: October 1, 2007
Creator: Booth, Corwin H; Jin, Geng Bang; Choi, Eun Sang; Guertin, Robert P.; Brooks, James S.; Booth, Corwin H. et al.
Partner: UNT Libraries Government Documents Department
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Optimization of the Helical Orbits in the Tevatron

Description: To avoid multiple head-on collisions the proton and antiproton beams in the Tevatron move along separate helical orbits created by 7 horizontal and 8 vertical electrostatic separators. Still the residual long-range beam-beam interactions can adversely affect particle motion at all stages from injection to collision. With increased intensity of the beams it became necessary to modify the orbits in order to mitigate the beam-beam effect on both antiprotons and protons. This report summarizes the … more
Date: June 1, 2007
Creator: Alexahin, Y.
Partner: UNT Libraries Government Documents Department
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World Sheet Commuting beta-gamma CFT and Non-Relativistic StringTheories

Description: We construct a sigma model in two dimensions with Galilean symmetry in flat target space similar to the sigma model of the critical string theory with Lorentz symmetry in 10 flat spacetime dimensions. This is motivated by the works of Gomis and Ooguri[1] and Danielsson et. al.[2, 3]. Our theory is much simpler than their theory and does not assume a compact coordinate. This non-relativistic string theory has a bosonic matter {beta}{gamma} CFT with the conformal weight of {beta} as 1. It is natu… more
Date: August 30, 2007
Creator: Kim, Bom Soo
Partner: UNT Libraries Government Documents Department
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Shape Determination for Deformed Electromagnetic Cavities

Description: The measured physical parameters of a superconducting cavity differ from those of the designed ideal cavity. This is due to shape deviations caused by both loose machine tolerances during fabrication and by the tuning process for the accelerating mode. We present a shape determination algorithm to solve for the unknown deviations from the ideal cavity using experimentally measured cavity data. The objective is to match the results of the deformed cavity model to experimental data through least-… more
Date: December 10, 2007
Creator: Akcelik, Volkan; Ko, Kwok; Lee, Lie-Quan; Li, Zhenghai; Ng, Cho-Kuen & Xiao, Liling
Partner: UNT Libraries Government Documents Department
open access

An array of low-background 3He proportional counters for theSudbury Neutrino Observatory

Description: An array of Neutral-Current Detectors (NCDs) has been builtin order to make a unique measurement of the total active ux of solarneutrinos in the Sudbury Neutrino Observatory (SNO). Data in the thirdphase of the SNO experiment were collected between November 2004 andNovember 2006, after the NCD array was added to improve theneutral-current sensitivity of the SNO detector. This array consisted of36 strings of proportional counters lled with a mixture of 3He and CF4gas capable of detecting the neu… more
Date: February 1, 2007
Creator: Amsbaugh, J. F.; Anaya, J. M.; Banar, J.; Bowles, T. J.; Browne, M. C.; Bullard, T. V. et al.
Partner: UNT Libraries Government Documents Department
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The groundwater-land-surface-atmosphere connection: soil moisture effects on the atmospheric boundary layer in fully-coupled simulations

Description: This study combines a variably-saturated groundwater flow model and a mesoscale atmospheric model to examine the effects of soil moisture heterogeneity on atmospheric boundary layer processes. This parallel, integrated model can represent spatial variations in land-surface forcing driven by three-dimensional (3D) atmospheric and subsurface components. The development of atmospheric flow is studied in a series of idealized test cases with different initial soil moisture distributions generated b… more
Date: February 2, 2007
Creator: Maxwell, R M; Chow, F K & Kollet, S J
Partner: UNT Libraries Government Documents Department
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Tevatron results on the discovery of sigma^(*)_b, b_s oscillations and the measurement of delta m_s, the lifetime difference delta gamma_s and the cp-violating phase phi

Description: The author discusses results from the Tevatron experiments on mixing and CP-violation in B{sub s} mesons, including the observation of B{sub s} oscillations and the first precision measurement of the mixing frequency, as well as a measurement of the lifetime difference {Delta}{Lambda}{sub s} and the first measurement of the CP-violating phase {delta}{sub s}. The author also briefly reports on the observation of four new bottom baryons at CDF.
Date: October 1, 2007
Creator: Heijboer, Aart
Partner: UNT Libraries Government Documents Department
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Water, law, science

Description: In a world with water resources severely impacted bytechnology, science must actively contribute to water law. To this end,this paper is an earth scientist s attempt to comprehend essentialelements of water law, and to examine their connections to science.Science and law share a common logical framework of starting with apriori prescribed tenets, and drawing consistent inferences. In science,observationally established physical laws constitute the tenets, while inlaw, they stem from social valu… more
Date: October 17, 2007
Creator: Narasimhan, T.N.
Partner: UNT Libraries Government Documents Department
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Radioactive Elements in the Standard Atomic Weights Table.

Description: In the 1949 Report of the Atomic Weights Commission, a series of new elements were added to the Atomic Weights Table. Since these elements had been produced in the laboratory and were not discovered in nature, the atomic weight value of these artificial products would depend upon the production method. Since atomic weight is a property of an element as it occurs in nature, it would be incorrect to assign an atomic weight value to that element. As a result of that discussion, the Commission deci… more
Date: August 4, 2007
Creator: Holden, N. E.
Partner: UNT Libraries Government Documents Department
open access

Demonstration of Femtosecond-Phase Stabilization in 2 km OpticalFiber

Description: Long-term phase drifts of less than a femtosecond per hour have been demonstrated in a 2 km length of single-mode optical fiber, stabilized interferometrically at 1530 nm. Recent improvements include a wide-band phase detector that reduces the possibility of fringe jumping due to fast external perturbations of the fiber and locking of the master CW laser wavelength to an atomic absorption line. Mode-locked lasers may be synchronized using two wavelengths of the comb, multiplexed over one fiber,… more
Date: June 1, 2007
Creator: Staples, J. W.; Wilcox, R. & Byrd, J. M.
Partner: UNT Libraries Government Documents Department
open access

Study of the Tau- to Pi- Pi+ Pi- Pi0 Nu/Tau And Tau- to Pi- Pi- Pi+ Eta Nu/Tau Decays Using the BaBar Detector

Description: The {tau}{sup -} {yields} {pi}{sup -}{pi}{sup +}{pi}{sup -}{nu}{sub {tau}} and {tau}{sup -} {yields} {pi}{sup -}{pi}{sup -}{pi}{sup +}{eta}{nu}{sub {tau}} decays have been studied with the BABAR detector. Preliminary branching fractions on the two modes are presented. The {tau}{sup -} {yields} {pi}{sup -}{pi}{sup -}{pi}{sup +}{eta}{nu}{sub {tau}} mode is found to have a large contribution from the {tau}{sup -} {yields} {omega}{pi}{sup -}{nu}{sub {tau}} decay. The {tau}{sup -} {yields} {pi}{sup … more
Date: November 14, 2007
Creator: Sobie, Randall
Partner: UNT Libraries Government Documents Department
open access

COMPARISONS OF CRYSTALLINE SILICOTITANATE AND RESORCINOL FORMALDEHYDE MEDIA FOR CESIUM REMOVAL BY IN-TANK COLUMN PROCESSING

Description: Chemical and thermal performance of crystalline silicotitanate (CST) and resorcinol-formaldehyde (RF) ion exchange media were predicted for column configurations designed for installation in high level waste tanks and intended for cesium removal from radioactive waste supernates. Modeling predictions for the processing of a known Savannah River Site tank waste composition were generated. In a two column configuration under presumed nominal operating conditions (432 gallon packed bed, 10 gpm liq… more
Date: November 7, 2007
Creator: King, W; Frank02 Smith, F; Si Lee, S & Daniel McCabe, D
Partner: UNT Libraries Government Documents Department
open access

Measurement of correlated b-bbar production in p-pbar collisions at s**(1/2) = 1960 GeV

Description: We present a measurement of the correlated b{bar b} production cross section. The data used in this analysis were taken with the upgraded CDF detector (CDF II) at the Fermilab Tevatron collider, and correspond to an integrated luminosity of 742 pb{sup -1}. We utilize muon pairs with invariant mass 5 {le} m{sub {mu}{mu}} {le} 80 GeV/c{sup 2} produced by b{bar b} double semileptonic decays. For muons with p{sub T} {ge} 3 GeV/c and |{eta}| {le} 0.7, that are produced by b and {bar b} quarks with p… more
Date: November 1, 2007
Creator: Aaltonen, T.; Abulencia, A.; Adelman, J.; Affolder, T.; Akimoto, T.; Albrow, M. G. et al.
Partner: UNT Libraries Government Documents Department
open access

Kinetics of the water adsorption driven structural transformationof ZnS nanoparticles

Description: Nanoparticles of certain materials can respond structurally to changes in their surface environments. We have previously shown that methanol, water adsorption, and aggregation-disaggregation can change the structure of 3 nm diameter zinc sulfide (ZnS). However, in prior observations of water-driven structure change, aggregation may also have taken place. Therefore, we investigated the structural consequences of water adsorption alone on anhydrous nanoparticles that were dried to minimize change… more
Date: August 1, 2007
Creator: Goodell, C. M.; Gilbert, B.; Weigand, S. J. & Banfield, J. F.
Partner: UNT Libraries Government Documents Department
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A High-Order Finite-Volume Algorithm for Fokker-Planck Collisions in Magnetized Plasmas

Description: A high-order finite volume algorithm is developed for the Fokker-Planck Operator (FPO) describing Coulomb collisions in strongly magnetized plasmas. The algorithm is based on a general fourth-order reconstruction scheme for an unstructured grid in the velocity space spanned by parallel velocity and magnetic moment. The method provides density conservation and high-order-accurate evaluation of the FPO independent of the choice of the velocity coordinates. As an example, a linearized FPO in const… more
Date: April 18, 2007
Creator: Xiong, Z; Cohen, R H; Rognlien, T D & Xu, X Q
Partner: UNT Libraries Government Documents Department
open access

Characterization of an AO-OCT system

Description: Adaptive optics (AO) and optical coherence tomography (OCT) are powerful imaging modalities that, when combined, can provide high-volumetric-resolution, images of the retina. The AO-OCT system at UC Davis has been under development for 2 years and has demonstrated the utility of this technology for microscopic, volumetric, in vivo retinal imaging [1]. The current system uses an AOptix bimorph deformable mirror (DM) for low-order, high-stroke correction [2] and a 140-actuator Boston Micromachine… more
Date: July 26, 2007
Creator: Evans, J. W.; Zawadzki, R. J.; Jones, S.; Olivier, S. & Werner, J. S.
Partner: UNT Libraries Government Documents Department
open access

Some Interesting Min-Bias Distributions for Early LHC Runs

Description: A few observable distributions in min-bias (inelastic, non-diffractive) events which could be well constrained with early LHC data are presented, with some comments on their significance for placing constraints on theoretical models. The effects of fiducial cuts (p{perpendicular} > 0.5 GeV, |{eta}| < 2.5) and extrapolation from the Tevatron are illustrated.
Date: December 1, 2007
Creator: Skands, P. Z.
Partner: UNT Libraries Government Documents Department
open access

Progress In High Temperature Electrolysis At The Idaho National Laboratory

Description: The United States is considering the development of a domestic hydrogen-based energy economy. Hydrogen is of particular interest as a secondary energy carrier because it has the potential to be storable, transportable, environmentally benign, and useful in many chemical processes. Obviously, before a hydrogen economy can be implemented, an efficient and environmentally friendly means for large scale hydrogen production must be identified, proven, and developed. Hydrogen is now produced primaril… more
Date: October 1, 2007
Creator: Stoots, Carl M.; E.O'Brien, James; Herring, J. Steve & Hartvigsen, Joseph
Partner: UNT Libraries Government Documents Department
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A Compact Linac for Proton Therapy Based on a Dielectric Wall Accelerator

Description: A novel compact CT-guided intensity modulated proton radiotherapy (IMPT) system is described. The system is being designed to deliver fast IMPT so that larger target volumes and motion management can be accomplished. The system will be ideal for large and complex target volumes in young patients. The basis of the design is the dielectric wall accelerator (DWA) system being developed at the Lawrence Livermore National Laboratory (LLNL). The DWA uses fast switched high voltage transmission lines … more
Date: October 29, 2007
Creator: Caporaso, G. J.; Mackie, T. R.; Sampayan, S.; Chen, Y.; Wang, L.; Blackfield, D. et al.
Partner: UNT Libraries Government Documents Department
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The polarized SRF gun experiment.

Description: RF electron guns are capable of producing electron bunches with high brightness, which outperform DC electron guns and may even be able to provide electron beams for the ILC without the need for a damping ring. However, all successful existing guns for polarized electrons are DC guns because the environment inside an RF gun is hostile to the GaAs cathode material necessary for polarization. While the typical vacuum pressure in a DC gun is better than 10{sup -11} torr the vacuum in an RF gun is … more
Date: September 10, 2007
Creator: Kewisch, J.; Ben-Zvi, Ilan; Rao, T.; Burrill, A.; Pate, D.; Grover, R. et al.
Partner: UNT Libraries Government Documents Department
open access

Numerical modeling of self-limiting and self-enhancing caprock alteration induced by CO2 storage in a depleted gas reservoir

Description: This paper presents numerical simulations of reactive transport which may be induced in the caprock of an on-shore depleted gas reservoir by the geological sequestration of carbon dioxide. The objective is to verify that CO{sub 2} geological disposal activities currently being planned for the study area are safe and do not induce any undesired environmental impact. In our model, fluid flow and mineral alteration are induced in the caprock by penetration of high CO{sub 2} concentrations from the… more
Date: September 7, 2007
Creator: Xu, Tianfu; Gherardi, Fabrizio; Xu, Tianfu & Pruess, Karsten
Partner: UNT Libraries Government Documents Department
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