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X-Ray Active Matrix Pixel Sensors Basedon J-FET Technology Developed for the Linac Coherent Light Source.

Description: An X-ray Active Matrix Pixel Sensor (XAMPS) is being developed for recording data for the X-ray Pump Probe experiment at the Linac Coherent Light Source (LCLS). Special attention has to be paid to some technological challenges that this design presents. New processes were developed and refined to address problems encountered during previous productions of XAMPS. The development of these critical steps and corresponding tests results are reported here.
Date: October 29, 2007
Creator: Carini, G. A.; Chen, W.; Li, Z.; Rehak, P. & Siddons, D. P.
Partner: UNT Libraries Government Documents Department
open access

Compact Analytic Expression for the Electric Field of a 2DElliptical Charge Distribution Inside a Perfectly Conducting CircularCylinder

Description: By combining the method of images with calculus of complex variables, we provide a simple expression for the electric field of a two-dimensional (2D) static elliptical charge distribution inside a perfectly conducting cylinder. The charge distribution need not be concentric with the cylinder.
Date: May 29, 2007
Creator: Furman, M. A.
Partner: UNT Libraries Government Documents Department
open access

In-situ X-ray photoelectron spectroscopy studies of water on metals and oxides at ambient conditions

Description: X-ray photoelectron spectroscopy (XPS) is a powerful tool for surface and interface analysis, providing the elemental composition of surfaces and the local chemical environment of adsorbed species. Conventional XPS experiments have been limited to ultrahigh vacuum (UHV) conditions due to a short mean free path of electrons in a gas phase. The recent advances in instrumentation coupled with third-generation synchrotron radiation sources enables in-situ XPS measurements at pressures above 5 Torr.… more
Date: October 29, 2007
Creator: Salmeron, Miquel; Yamamoto, S.; Bluhm, H.; Andersson, K.; Ketteler, G.; Ogasawara, H. et al.
Partner: UNT Libraries Government Documents Department
open access

Evidence for Merging or Disruption of Red Galaxies from the Evolution of Their Clustering

Description: The formation and evolution of massive red galaxies form a crucial test of theories of galaxy formation based on hierarchical assembly. In this Letter we use observations of the clustering of luminous red galaxies from the Boötes field and N-body simulations to argue that about of the most luminous satellite galaxies appear to undergo merging or disruption within massive halos between and 0.5.
Date: November 29, 2006
Creator: White, Martin; White, Martin; Zheng, Zheng; Brown, Michael J. I.; Dey, Arjun & Jannuzi, Buell T.
Partner: UNT Libraries Government Documents Department
open access

Using measured equipment load profiles to 'right-size' HVACsystems and reduce energy use in laboratory buildings (Pt. 2)

Description: There is a general paucity of measured equipment load datafor laboratories and other complex buildings and designers often useestimates based on nameplate rated data or design assumptions from priorprojects. Consequently, peak equipment loads are frequentlyoverestimated, and load variation across laboratory spaces within abuilding is typically underestimated. This results in two design flaws.Firstly, the overestimation of peak equipment loads results in over-sizedHVAC systems, increasing initia… more
Date: June 29, 2005
Creator: Mathew, Paul; Greenberg, Steve; Frenze, David; Morehead, Michael; Sartor, Dale & Starr, William
Partner: UNT Libraries Government Documents Department
open access

Rapid Reagentless Detection of M. tuberculosis H37Ra in Respiratory Effluents

Description: Two similar mycobacteria, Mycobacteria tuberculosis H37Ra and Mycobacteria smegmatis are rapidly detected and identified within samples containing a complex background of respiratory effluents using Single Particle Aerosol Mass Spectrometry (SPAMS). M. tuberculosis H37Ra (TBa), an avirulent strain, is used as a surrogate for virulent tuberculosis (TBv); M. smegmatis (MSm) is utilized as a near neighbor confounder for TBa. Bovine lung surfactant and human exhaled breath condensate are used as fi… more
Date: January 29, 2008
Creator: Adams, K L; Steele, P T; Bogan, M J; Sadler, N M; Martin, S; Martin, A N et al.
Partner: UNT Libraries Government Documents Department
open access

Dirac charge dynamics in graphene by infrared spectroscopy

Description: A remarkable manifestation of the quantum character of electrons in matter is offered by graphene, a single atomic layer of graphite. Unlike conventional solids where electrons are described with the Schrödinger equation, electronic excitations in graphene are governed by the Dirac hamiltonian. Some of the intriguing electronic properties of graphene, such as massless Dirac quasiparticles with linear energy-momentum dispersion, have been confirmed by recent observations. Here, we report an… more
Date: April 29, 2008
Creator: Martin, Michael C.; Li, Z. Q.; Henriksen, E. A.; Jiang, Z.; Hao, Z.; Martin, Michael C et al.
Partner: UNT Libraries Government Documents Department
open access

Direct Photons at RHIC

Description: Direct photons are ideal tools to investigate kinematical and thermodynamical conditions of heavy ion collisions since they are emitted from all stages of the collision and once produced they leave the interaction region without further modification by the medium. The PHENIX experiment at RHIC has measured direct photon production in p+p and Au+Au collisions at 200 GeV over a wide transverse momentum (p{sub T}) range. The p+p measurements allow a fundamental test of QCD, and serve as a baseline… more
Date: July 29, 2008
Creator: Gabor,D.
Partner: UNT Libraries Government Documents Department
open access

SALT CORE SAMPLING EVOLUTION AT THE SAVANNAH RIVER SITE

Description: The Savannah River Site (SRS), a Department of Energy (DOE) facility, has over 30 million gallons of legacy waste from its many years of processing nuclear materials. The majority of waste is stored in 49 buried tanks. Available underground piping is the primary and desired pathway to transfer waste from one tank to another until the waste is delivered to the glass plant, DWPF, or the grout plant, Saltstone. Prior to moving the material, the tank contents need to be evaluated to ensure the corr… more
Date: November 29, 2007
Creator: Nance, T; Daniel Krementz, D & William Cheng, W
Partner: UNT Libraries Government Documents Department
open access

Design and Construction Solutions in the Accurate Realization of NCSX Magnetic Fields

Description: The National Compact Stellarator Experiment, NCSX, is being constructed at the Princeton Plasma Physics Laboratory (PPPL) in partnership with the Oak Ridge national Laboratory. The goal of NCSX is to provide the understanding necessary to develop an attractive, disruption free, steady state compact stellaratorbased reactor design. This paper describes the recently revised designs of the critical interfaces between the modular coils, the construction solutions developed to meet assembly toleranc… more
Date: September 29, 2008
Creator: Heitzenroeder, P.; Dudek, Lawrence E.; Brooks, Arthur W.; Viola, Michael E.; Brown, Thomas; Neilson, George H. et al.
Partner: UNT Libraries Government Documents Department
open access

Surface Specularity as an Indicator of Shock-Induced Solid-Liquid Phase Transitions

Description: When highly polished metal surfaces melt upon release after shock loading, they exhibit a number of features that suggest that significant surface changes accompany the phase transition. The reflection of light from such surfaces changes from specular (pre-shock) to diffuse upon melting. A familiar manifestation of this phenomenon is the loss of signal light in velocimetric measurements typically observed above pressures high enough to melt the free-surface. Unlike many other potential material… more
Date: June 29, 2007
Creator: Gerald Stevens, Stephen Lutz, William Turley, Lynn Veeser
Partner: UNT Libraries Government Documents Department
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Comparison of kinetic and equilibrium reaction models insimulating gas hydrate behavior in porous media

Description: In this study we compare the use of kinetic and equilibriumreaction models in the simulation of gas (methane) hydrate behavior inporous media. Our objective is to evaluate through numerical simulationthe importance of employing kinetic versus equilibrium reaction modelsfor predicting the response of hydrate-bearing systems to externalstimuli, such as changes in pressure and temperature. Specifically, we(1) analyze and compare the responses simulated using both reactionmodels for natural gas pro… more
Date: November 29, 2006
Creator: Kowalsky, Michael B. & Moridis, George J.
Partner: UNT Libraries Government Documents Department
open access

Repair of radiation-induced heat-labile sites is independent of DNA-PKcs, XRCC1 or PARP

Description: Ionizing radiation induces a variety of different DNA lesions: in addition to the most critical DNA damage, the DSB, numerous base alterations, SSBs and other modifications of the DNA double-helix are formed. When several non-DSB lesions are clustered within a short distance along DNA, or close to a DSB, they may interfere with the repair of DSBs and affect the measurement of DSB induction and repair. We have previously shown that a substantial fraction of DSBs measured by pulsed-field gel elec… more
Date: April 29, 2008
Creator: Stenerlöw, Bo; Karlsson, Karin H.; Radulescu, Irina; Rydberg, Bjorn & Stenerlow, Bo
Partner: UNT Libraries Government Documents Department
open access

Effect of Random Clustering on Surface Damage Density Estimates

Description: Identification and spatial registration of laser-induced damage relative to incident fluence profiles is often required to characterize the damage properties of laser optics near damage threshold. Of particular interest in inertial confinement laser systems are large aperture beam damage tests (>1cm{sup 2}) where the number of initiated damage sites for {phi}>14J/cm{sup 2} can approach 10{sup 5}-10{sup 6}, requiring automatic microscopy counting to locate and register individual damage si… more
Date: October 29, 2007
Creator: Matthews, M J & Feit, M D
Partner: UNT Libraries Government Documents Department
open access

Inelastic final-state interaction

Description: The final-state interaction in multichannel decay processes is systematically studied with application to B decay in mind. Since the final-state interaction is intrinsically interwoven with the decay interaction in this case, no simple phase theorem like"Watson's theorem" holds for experimentally observed final states. We first examine in detail the two-channel problem as a toy-model to clarify the issues and to remedy common mistakes made in earlier literature. Realistic multicha… more
Date: October 29, 2007
Creator: Suzuki, Mahiko & Suzuki, Mahiko
Partner: UNT Libraries Government Documents Department
open access

Subaru Weak Lensing Measurements of Four Strong Lensing Clusters: Are Lensing Clusters Over-Concentrated?

Description: We derive radial mass profiles of four strong lensing selected clusters which show prominent giant arcs (Abell 1703, SDSS J1446+3032, SDSS J1531+3414, and SDSS J2111-0115), by combining detailed strong lens modeling with weak lensing shear measured from deep Subaru Suprime-cam images. Weak lensing signals are detected at high significance for all four clusters, whose redshifts range from z = 0.28 to 0.64. We demonstrate that adding strong lensing information with known arc redshifts significant… more
Date: January 29, 2009
Creator: Oguri, Masamune; Hennawi, Joseph F.; Gladders, Michael D.; Dahle, Haakon; Natarajan, Priyamvada; Dalal, Neal et al.
Partner: UNT Libraries Government Documents Department
open access

Downstream Intensification Effects Associated with CO2 Laser Mitigation of Fused Silica

Description: Mitigation of 351nm laser-induced damage sites on fused silica exit surfaces by selective CO{sub 2} treatment has been shown to effectively arrest the exponential growth responsible for limiting the lifetime of optics in high-fluence laser systems. However, the perturbation to the optical surface profile following the mitigation process introduces phase contrast to the beam, causing some amount of downstream intensification with the potential to damage downstream optics. Control of the laser tr… more
Date: October 29, 2007
Creator: Matthews, M. J.; Bass, I. L.; Guss, G. M.; Widmayer, C. C. & Ravizza, F. L.
Partner: UNT Libraries Government Documents Department
open access

Shape transitions in neutron-rich Ru isotopes: spectroscopy of 109,110,111,112Ru

Description: The spectroscopy of neutron-rich {sup 109,110,111,112}Ru nuclei was studied by measuring the prompt {gamma} rays originated from fission fragments, produced by the {sup 238}U({alpha},f) fusion-fission reaction, in coincidence with the detection of both fragments. For {sup 109,111}Ru, both the negative-parity (h{sub 11/2} orbitals) and positive-parity (g{sub 7/2} and/or d{sub 5/2} orbitals) bands were extended to substantially higher spin and excitation energy than known previously. The ground-s… more
Date: June 29, 2005
Creator: Hua, H.; Cline, D.; Hayes, A. B.; Teng, R.; Riley, D.; Clark, R. M. et al.
Partner: UNT Libraries Government Documents Department
open access

Correlations between Optical, Chemical and Physical Properties of Biomass Burn Aerosols

Description: Aerosols generated from burning different plant fuels were characterized to determine relationships between chemical, optical and physical properties. Single scattering albedo ({omega}) and Angstrom absorption coefficients ({alpha}{sub ap}) were measured using a photoacoustic technique combined with a reciprocal nephelometer. Carbon-to-oxygen atomic ratios, sp{sup 2} hybridization, elemental composition and morphology of individual particles were measured using scanning transmission X-ray micro… more
Date: January 29, 2008
Creator: Hopkins, Rebecca J.; Lewis, K.; Desyaterik, Yury; Wang, Z.; Tivanski, Alexei V.; Arnott, W. P. et al.
Partner: UNT Libraries Government Documents Department
open access

A Validation of FEM3MP with Joint Urban 2003 Data

Description: Under the sponsorship of the U.S. DOE and DHS, we have recently developed a computational fluid dynamics (CFD) model for simulating airflow and dispersion of chemical/biological agents released in urban areas. Our model, FEM3MP, is based on solving the three-dimensional, time-dependent Navier-Stokes equations with appropriate physics submodels on massively parallel computer platforms. It employs finite-element discretization for effective treatment of complex geometries and a semi-implicit proj… more
Date: August 29, 2006
Creator: Chan, S T & Leach, M J
Partner: UNT Libraries Government Documents Department
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