Cosmography From Two-Image Lens Systems: Overcoming the Lens Profile Slope Degeneracy (open access)

Cosmography From Two-Image Lens Systems: Overcoming the Lens Profile Slope Degeneracy

None
Date: April 25, 2013
Creator: Suyu, S.H. & /UC, Santa Barbara /KIPAC, Menlo Park
System: The UNT Digital Library
Deflection of MeV Electrons by Self-Generated Magnetic Fields in Intense Laser-Solid Interaction (open access)

Deflection of MeV Electrons by Self-Generated Magnetic Fields in Intense Laser-Solid Interaction

None
Date: April 25, 2013
Creator: Perez, F.; Kemp, A. J.; Divol, L.; Chen, C. D. & Patel, P. K.
System: The UNT Digital Library
Dissecting the Gravitational Lens B1608 656. I. Lens Potential Reconstruction (open access)

Dissecting the Gravitational Lens B1608 656. I. Lens Potential Reconstruction

None
Date: April 25, 2013
Creator: Suyu, S. H.; Marshall, P. J.; Blandford, R. D.; Fassnacht, C. D.; Koopmans, L. V. E.; McKean, J. P. et al.
System: The UNT Digital Library
Interaction-Based Load Balancing in N-body Simulations (open access)

Interaction-Based Load Balancing in N-body Simulations

None
Date: April 25, 2013
Creator: Pearce, O.; Gamblin, T.; Schulz, M.; de Supinski, B. R. & Amato, N. M.
System: The UNT Digital Library
Titanium dxy Ferromagnetism at the LaAlO3/SrTiO3 Interface (open access)

Titanium dxy Ferromagnetism at the LaAlO3/SrTiO3 Interface

None
Date: April 25, 2013
Creator: Lee, J. S.; Xie, Y. W.; Sato, H. K.; Bell, C.; Hikita, Y.; Hwang, H. Y. et al.
System: The UNT Digital Library
Unbound Particles in Dark Matter Halos (open access)

Unbound Particles in Dark Matter Halos

None
Date: April 25, 2013
Creator: Behroozi, Peter S.; /KIPAC, Menlo Park /Stanford U., Phys. Dept. /SLAC; Loeb, Abraham; U., /Harvard; Wechsler, Risa H. & /KIPAC, Menlo Park /Stanford U., Phys. Dept. /SLAC
System: The UNT Digital Library
Searches for Leptonic B Decays at BaBar (open access)

Searches for Leptonic B Decays at BaBar

Measurements of the branching fractions of purely leptonic decays of B-mesons translate into constraints in the plane of the charged Higgs mass versus tan {beta} which are relatively insensitive to the particular theoretical model. Using the full BABAR dataset of 450 million B-decays we search for these decays. No significant signal is found in the decays into electrons or muons and we set upper limits on the branching fractions of the order of a 10{sup -6} at 90% confidence level. We measure the branching fraction of B {yields} {tau}{mu} to be (1.7 {+-} 0.6) x 10{sup -4}.
Date: April 25, 2012
Creator: Nelson, Silke
System: The UNT Digital Library
Growth of detector-grade CZT by Traveling Heater Method (THM): An advancement (open access)

Growth of detector-grade CZT by Traveling Heater Method (THM): An advancement

In this present work we report the growth of Cd{sub 0.9}Zn{sub 0.1}Te doped with In by a modified THM technique. It has been demonstrated that by controlling the microscopically flat growth interface, the size distribution and concentration can be drastically reduced in the as-grown ingots. This results in as-grown detector-grade CZT by the THM technique. The three-dimensional size distribution and concentrations of Te inclusions/precipitations were studied. The size distributions of the Te precipitations/inclusions were observed to be below the 10-{micro}m range with the total concentration less than 10{sup 5} cm{sup -3}. The relatively low value of Te inclusions/precipitations results in excellent charge transport properties of our as-grown samples. The ({mu}{tau}){sub e} values for different as-grown samples varied between 6-20 x 10{sup -3} cm{sup 2}/V. The as-grown samples also showed fairly good detector response with resolution of {approx}1.5%, 2.7% and about 3.8% at 662 keV for quasi-hemispherical geometry for detector volumes of 0.18 cm{sup 3}, 1 cm{sup 3} and 4.2 cm{sup 3}, respectively.
Date: April 25, 2011
Creator: ROY, U.N.; JAMES, R.; WEILER, S.; STEIN, J.; GROZA, M.; BURGER, A. et al.
System: The UNT Digital Library
IMPROVEMENT OF CdMnTe DETECTOR PERFORMANCE BY MnTe PURIFICATION (open access)

IMPROVEMENT OF CdMnTe DETECTOR PERFORMANCE BY MnTe PURIFICATION

Residual impurities in manganese (Mn) are a big obstacle to obtaining high-performance CdMnTe (CMT) X-ray and gamma-ray detectors. Generally, the zone-refining method is an effective way to improve the material's purity. In this work, we purified the MnTe compounds combining the zone-refining method with molten Te, which has a very high solubility for most impurities. We confirmed the improved purity of the material by glow-discharge mass spectrometry (GDMS). We also found that CMT crystals from a multiply-refined MnTe source, grown by the vertical Bridgman method, yielded better performing detectors.
Date: April 25, 2011
Creator: Kim, K. H.; Bolotnikov, A. E.; Camarda, G. S.; Tappero, R.; Hossain, A.; Cui, Y. et al.
System: The UNT Digital Library
Overview of the 2009 Release of the Evaluated Nuclear Data Library (endl2009) (open access)

Overview of the 2009 Release of the Evaluated Nuclear Data Library (endl2009)

The Lawrence Livermore National Laboratory (LLNL) Physics Division has produced the next iteration of LLNL's evaluated nuclear database, ENDL2009. ENDL2009 is the second in a series of major ENDL library releases designed to support LLNL's current and future nuclear data needs. This library includes 585 distinct transport-ready evaluations in the neutron sub-library and many physics improvements for stockpile stewardship, attribution signatures, key radiochemical diagnostics and performance of conventional and hybrid fission/fusion reactors. In building this library, we adopted the best of the world's nuclear data efforts: 46% of the library is from the ENDF/B-VII.0 library, 10% is from the JENDL libraries and 8% from other libraries. The remaining 36% of the neutron sub-library and all of the charged-particle sub-libraries consist of new evaluations developed at LLNL for the ENDL2009 library. In addition, ENDL2009 supports new features such as energy-dependent Q values from fission, support for unresolved resonances and average momentum deposition. Finally, this release is our most highly tested release as we have strengthened our already rigorous testing regime by adding tests against LANL Activation Ratio Measurements and more than 1200 new critical assemblies. Our testing is now being incorporated into our development process and is serving to guide database …
Date: April 25, 2010
Creator: Brown, D. A.; Beck, B.; Descalle, M.; Hoffman, R.; Ormand, E.; Navratil, P. et al.
System: The UNT Digital Library
Search for Muon Neutrino Disappearance in a Short-Baseline Accelerator Neutrino Beam (open access)

Search for Muon Neutrino Disappearance in a Short-Baseline Accelerator Neutrino Beam

We report a search for muon neutrino disappearance in the {Delta}m{sup 2} region of 0.5--40 eV{sup 2} using data from both Sci-BooNE and MiniBooNE experiments. SciBooNE data provides a constraint on the neutrino flux, so that the sensitivity to {nu}{sub {mu}} disappearance with both detectors is better than with just MiniBooNE alone. The preliminary sensitivity for a joint {nu}{sub {mu}} disappearance search is presented.
Date: April 25, 2010
Creator: Nakajima, Y. & U., /Kyoto
System: The UNT Digital Library
Design and Implementation of a Facility for Discovering New Scintillator Materials (open access)

Design and Implementation of a Facility for Discovering New Scintillator Materials

We describe the design and operation of a high-throughput facility for synthesizing thousands of inorganic crystalline samples per year and evaluating them as potential scintillation detector materials. This facility includes a robotic dispenser, arrays of automated furnaces, a dual-beam X-ray generator for diffractometery and luminescence spectroscopy, a pulsed X-ray generator for time response measurements, computer-controlled sample changers, an optical spectrometer, and a network-accessible database management system that captures all synthesis and measurement data.
Date: April 25, 2008
Creator: Derenzo, Stephen; Derenzo, Stephen E; Boswell, Martin S.; Bourret-Courchesne, Edith; Boutchko, Rostyslav; Budinger, Thomas F. et al.
System: The UNT Digital Library
The eukaryotic translation elongation factor eEF1A2 induces neoplastic properties and mediates tumorigenic effects of ZNF217 in precursor cells of human ovarian carcinomas (open access)

The eukaryotic translation elongation factor eEF1A2 induces neoplastic properties and mediates tumorigenic effects of ZNF217 in precursor cells of human ovarian carcinomas

Ovarian epithelial carcinomas (OEC) frequently exhibit amplifications at the 20q13 locus which is the site of several oncogenes, including the eukaryotic elongation factor EEF1A2 and the transcription factor ZNF217. We reported previously that overexpressed ZNF217 induces neoplastic characteristics in precursor cells of OEC. Unexpectedly, ZNF217, which is a transcriptional repressor, enhanced expression of eEF1A2. In this study, array comparative genomic hybridization, single nucleotide polymorphism and Affymetrix analysis of ZNF217-overexpressing cell lines confirmed consistently increased expression of eEF1A2 but not of other oncogenes, and revealed early changes in EEF1A2 gene copy numbers and increased expression at crisis during immortalization. We defined the influence of eEF1A2 overexpression on immortalized ovarian surface epithelial cells, and investigated interrelationships between effects of ZNF217 and eEF1A2 on cellular phenotypes. Lentivirally induced eEF1A2 overexpression caused delayed crisis, apoptosis resistance and increases in serum-independence, saturation densities, and anchorage independence. siRNA to eEF1A2 reversed apoptosis resistance and reduced anchorage independence in eEF1A2-overexpressing lines. Remarkably, siRNA to eEF1A2 was equally efficient in inhibiting both anchorage independence and resistance to apoptosis conferred by ZNF217 overexpression. Our data define neoplastic properties that are caused by eEF1A2 in nontumorigenic ovarian cancer precursor cells, and suggest that eEF1A2 plays a role in mediating ZNF217-induced …
Date: April 25, 2008
Creator: Sun, Yu; Wong, Nicholas; Guan, Yinghui; Salamanca, Clara M.; Cheng, Jung Chien; Lee, Jonathan M. et al.
System: The UNT Digital Library
A Gridded Electron Gun for a Sheet Beam Klystron (open access)

A Gridded Electron Gun for a Sheet Beam Klystron

This paper describes the development of an electron gun for a sheet beam klystron. Initially intended for accelerator applications, the gun can operate at a higher perveance than one with a cylindrically symmetric beam. Results of 2D and 3D simulations are discussed.
Date: April 25, 2008
Creator: Read, M. E.; Miram, G.; Ives, R. L.; Ivanov, V. & Krasnykh, A.
System: The UNT Digital Library
Chemical Bonding and Structural Information of Black Carbon Reference Materials and Individual Carbonaceous Atmospheric Aerosols (open access)

Chemical Bonding and Structural Information of Black Carbon Reference Materials and Individual Carbonaceous Atmospheric Aerosols

The carbon-to-oxygen ratios and graphitic nature of a rangeof black carbon standard reference materials (BC SRMs), high molecularmass humic-like substances (HULIS) and atmospheric particles are examinedusing scanning transmission X-ray microscopy (STXM) coupled with nearedge X-ray absorption fine structure (NEXAFS) spectroscopy. UsingSTXM/NEXAFS, individual particles with diameter>100 nm are studied,thus the diversity of atmospheric particles collected during a variety offield missions is assessed. Applying a semi-quantitative peak fittingmethod to the NEXAFS spectra enables a comparison of BC SRMs and HULIS toparticles originating from anthropogenic combustion and biomass burns,thus allowing determination of the suitability of these materials forrepresenting atmospheric particles. Anthropogenic combustion and biomassburn particles can be distinguished from one another using both chemicalbonding and structural ordering information. While anthropogeniccombustion particles are characterized by a high proportion ofaromatic-C, the presence of benzoquinone and are highly structurallyordered, biomass burn particles exhibit lower structural ordering, asmaller proportion of aromatic-C and contain a much higher proportion ofoxygenated functional groups.
Date: April 25, 2007
Creator: Hopkins, Rebecca J.; Tivanski, Alexei V.; Marten, Bryan D. & Gilles, Mary K.
System: The UNT Digital Library
COMPARISON OF CONSEQUENCE ANALYSIS RESULTS FROM TWO METHODS OF PROCESSING SITE METEOROLOGICAL DATA (open access)

COMPARISON OF CONSEQUENCE ANALYSIS RESULTS FROM TWO METHODS OF PROCESSING SITE METEOROLOGICAL DATA

Consequence analysis to support documented safety analysis requires the use of one or more years of representative meteorological data for atmospheric transport and dispersion calculations. At minimum, the needed meteorological data for most atmospheric transport and dispersion models consist of hourly samples of wind speed and atmospheric stability class. Atmospheric stability is inferred from measured and/or observed meteorological data. Several methods exist to convert measured and observed meteorological data into atmospheric stability class data. In this paper, one year of meteorological data from a western Department of Energy (DOE) site is processed to determine atmospheric stability class using two methods. The method that is prescribed by the U.S. Nuclear Regulatory Commission (NRC) for supporting licensing of nuclear power plants makes use of measurements of vertical temperature difference to determine atmospheric stability. Another method that is preferred by the U.S. Environmental Protection Agency (EPA) relies upon measurements of incoming solar radiation, vertical temperature gradient, and wind speed. Consequences are calculated and compared using the two sets of processed meteorological data from these two methods as input data into the MELCOR Accident Consequence Code System 2 (MACCS2) code.
Date: April 25, 2007
Creator: Thoman, D. C. & Weber, A. H.
System: The UNT Digital Library
Diffuse gamm-ray Emission: Lessons and Perspectives (open access)

Diffuse gamm-ray Emission: Lessons and Perspectives

The Galactic diffuse emission is potentially able to reveal much about the sources and propagation of cosmic rays (CR), their spectra and intensities in distant locations. It can possibly unveil WIMP dark matter (DM) through its annihilation signatures. The extragalactic background may provide vital information about the early stages of the universe, neutralino annihilation, and unresolved sources (blazars) and their cosmological evolution. The g-ray instrument EGRET on the CGRO contributed much to the exploration of the Galactic diffuse emission. The new NASA Gamma-ray Large Area Space Telescope (GLAST) is scheduled for launch in 2007; study of the diffuse g-ray emission is one of the priority goals. We describe current understanding of the diffuse emission and its potential for future discoveries.
Date: April 25, 2007
Creator: Moskalenko, Igor V.; /NASA, Goddard; Strong, Andrew W. & /Garching, Max Planck Inst., MPE
System: The UNT Digital Library
Electron Positron Factories (open access)

Electron Positron Factories

None
Date: April 25, 2007
Creator: Zisman, Michael S.; Chattopadhyay, S.; Garren, Alper A.; Lambertson, Glen; Bloom, Elliott D.; Corbett, William J. et al.
System: The UNT Digital Library
Fabrication and In Vitro Deployment of a Laser-Activated Shape Memory Polymer Vascular Stent (open access)

Fabrication and In Vitro Deployment of a Laser-Activated Shape Memory Polymer Vascular Stent

Vascular stents are small tubular scaffolds used in the treatment of arterial stenosis (narrowing of the vessel). Most vascular stents are metallic and are deployed either by balloon expansion or by self-expansion. A shape memory polymer (SMP) stent may enhance flexibility, compliance, and drug elution compared to its current metallic counterparts. The purpose of this study was to describe the fabrication of a laser-activated SMP stent and demonstrate photothermal expansion of the stent in an in vitro artery model. A novel SMP stent was fabricated from thermoplastic polyurethane. A solid SMP tube formed by dip coating a stainless steel pin was laser-etched to create the mesh pattern of the finished stent. The stent was crimped over a fiber-optic cylindrical light diffuser coupled to an infrared diode laser. Photothermal actuation of the stent was performed in a water-filled mock artery. At a physiological flow rate, the stent did not fully expand at the maximum laser power (8.6 W) due to convective cooling. However, under zero flow, simulating the technique of endovascular flow occlusion, complete laser actuation was achieved in the mock artery at a laser power of {approx}8 W. We have shown the design and fabrication of an SMP stent and …
Date: April 25, 2007
Creator: Baer, G. M.; Small, W., IV; Wilson, T. S.; Benett, W. J.; Matthews, D. L.; Hartman, J. et al.
System: The UNT Digital Library
Gamma-ray Source Stacking Analysis at Low Galactic Latitude (open access)

Gamma-ray Source Stacking Analysis at Low Galactic Latitude

We studied the problematic of uncertainties in the diffuse gamma radiation apparent in stacking analysis of EGRET data at low Galactic latitudes. Subsequently, we co-added maps of counts, exposure and diffuse background, and residuals, in varying numbers for different sub-categories of putatively and known source populations (like PSRs). Finally we tested for gamma-ray excess emission in those maps and attempt to quantify the systematic biases in such approach. Such kind of an analysis will help the classification processes of sources and source populations in the GLAST era.
Date: April 25, 2007
Creator: Cillis, Analia N.; Reimer, Olaf & Torres, Diego F.
System: The UNT Digital Library
Hard Real Time Quick Exafs Data Acquisition With All Open Source Software on a Commodity Personal Computer. (open access)

Hard Real Time Quick Exafs Data Acquisition With All Open Source Software on a Commodity Personal Computer.

We describe here the data acquisition subsystem of the Quick EXAFS (QEXAFS) experiment at the National Synchrotron Light Source of Brookhaven National Laboratory. For ease of future growth and flexibility, almost all software components are open source with very active maintainers. Among them, Linux running on x86 desktop computer, RTAI for real-time response, COMEDI driver for the data acquisition hardware, Qt and PyQt for graphical user interface, PyQwt for plotting, and Python for scripting. The signal (A/D) and energy-reading (IK220 encoder) devices in the PCI computer are also EPICS enabled. The control system scans the monochromator energy through a networked EPICS motor. With the real-time kernel, the system is capable of deterministic data-sampling period of tens of micro-seconds with typical timing-jitter of several micro-seconds. At the same time, Linux is running in other non-real-time processes handling the user-interface. A modern Qt-based controls-front end enhances productivity. The fast plotting and zooming of data in time or energy coordinates let the experimenters verify the quality of the data before detailed analysis. Python scripting is built-in for automation. The typical data-rate for continuous runs are around ten mega-bytes per minute.
Date: April 25, 2007
Creator: So,I.; Siddons, D. P.; Caliebe, W. A. & Khalid, S.
System: The UNT Digital Library
Improved Measurement of CP Violation in Neutral BDecays to \ccbar s (open access)

Improved Measurement of CP Violation in Neutral BDecays to \ccbar s

The authors present updated measurements of time-dependent CP asymmetries in fully-reconstructed neutral B decays to several CP eigenstates containing a charmonium meson. The measurements use a data sample of (383 {+-} 4) x 10{sup 6} {Upsilon}(4S) {yields} B{bar B} decays collected with the BABAR detector at the PEP-II B factory. They determine sin2{beta} = 0.714 {+-} 0.032(stat) {+-} 0.018(syst) and |{lambda}| = 0.952 {+-} 0.022(stat) {+-} 0.017(syst).
Date: April 25, 2007
Creator: Aubert, B.; Bona, M.; Boutigny, D.; Karyotakis, Y.; Lees, J. P.; Poireau, V. et al.
System: The UNT Digital Library
Localized Electron States Near a Metal-SemiconductorNanocontact (open access)

Localized Electron States Near a Metal-SemiconductorNanocontact

The electronic structure of nanowires in contact withmetallic electrodes of experimentally relevant sizes is calculated byincorporating the electrostatic polarization potential into the atomisticsingle particle Schrodinger equation. We show that the presence of anelectrode produces localized electron/hole states near the electrode, aphenomenon only exhibited in nanostructures and overlooked in the past.This phenomenon will have profound implications on electron transport insuch nanosystems. We calculate several electrode/nanowire geometries,with varying contact depths and nanowire radii. We demonstrate the changein the band gap of up to 0.5 eV in 3 nm diameter CdSe nanowires andcalculate the magnitude of the applied electric field necessary toovercome the localization.
Date: April 25, 2007
Creator: Demchenko, Denis O. & Wang, Lin-Wang
System: The UNT Digital Library
Measurement of Decay Amplitudes of B to (ccbar) K^* withan Angular Analysis, for (ccbar)=J/Psi,Psi(2S) and Chi_c1 (open access)

Measurement of Decay Amplitudes of B to (ccbar) K^* withan Angular Analysis, for (ccbar)=J/Psi,Psi(2S) and Chi_c1

The authors perform the first three-dimensional measurement of the amplitudes of B {yields} {psi}(2S)K* and B {yields} {chi}{sub c1}K* decays and update the previous measurement B {yields} J/{psi}K*. They use a data sample collected with the BABAR detector at the PEP-II storage ring, corresponding to 232 million B{bar B} pairs. The longitudinal polarization of decays involving a J{sup PC} = 1{sup ++} {chi}{sub c1} meson is found to be larger than that with a 1{sup --} J/{psi} or {psi}(2S) meson. No direct CP-violating charge asymmetry is observed.
Date: April 25, 2007
Creator: Aubert, B.; Bona, M.; Boutigny, D.; Karyotakis, Y.; Lees, J. P.; Poireau, V. et al.
System: The UNT Digital Library