Accomplishments in Field Period Assembly for NCSX* This is how we did it (open access)

Accomplishments in Field Period Assembly for NCSX* This is how we did it

The National Compact Stellarator Experiment (NCSX) was a collaborative effort between ORNL and PPPL. PPPL provided the assembly techniques with guidance from ORNL to meet design criteria. The individual vacuum vessel segments, modular coils, trim coils, and toroidal field coils components were delivered to the Field Period Assembly (FPA) crew who then would complete the component assemblies and then assemble the final three field period assemblies, each consisting of two sets of three modular coils assembled over a 120o vacuum vessel segment with the trim coils and toroidal field coils providing the outer layer. The requirements for positioning the modular coils were found to be most demanding. The assembly tolerances required for accurate positioning of the field coil windings in order to generate sufficiently accurate magnetic fields strained state of the art techniques in metrology and alignment and required constant monitoring of assembly steps with laser trackers, measurement arms, and photogrammetry. The FPA activities were being performed concurrently while engineering challenges were being resolved. For example, it was determined that high friction electrically isolated shims were needed between the modular coil interface joints and low distortion welding was required in the nose region of those joints. This took months of …
Date: September 14, 2009
Creator: Michael Viola, J. Edwards, T. Brown, L. Dudek, R. Ellis, P. Heitzenroeder, R. Strykowsky and Michael Cole
Object Type: Article
System: The UNT Digital Library
Atmospheric Dispersion at Spatial Resolutions Below Mesoscale for university of Tennessee SimCenter at Chattanooga: Final Report (open access)

Atmospheric Dispersion at Spatial Resolutions Below Mesoscale for university of Tennessee SimCenter at Chattanooga: Final Report

In Year 1 of this project, items 1.1 and 1.2 were addressed, as well as item 2.2. The baseline parallel computational simulation tool has been refined significantly over the timeline of this project for the purpose of atmospheric dispersion and transport problems; some of these refinements are documented in Chapter 3. The addition of a concentration transport capability (item 1.2) was completed, along with validation and usage in a highly complex urban environment. Multigrid capability (item 2.2) was a primary focus of Year 1 as well, regardless of the fact that it was scheduled for Year 2. It was determined by the authors that due to the very large nature of the meshes required for atmospheric simulations at mesoscale, multigrid was a key enabling technology for the rest of the project to be successful. Therefore, it was addressed early according to the schedule laid out in the original proposal. The technology behind the multigrid capability is discussed in detail in Chapter 5. Also in Year 1, the issue of ground topography specification is addressed. For simulations of pollutant transport in a given region, a key prerequisite is the specification of the detailed ground topography. The local topography must be placed …
Date: September 14, 2009
Creator: Whitfield, Dr. David & Hyams, Dr. Daniel
Object Type: Report
System: The UNT Digital Library
Graphene Growth by Metal Etching on Ru (0001) (open access)

Graphene Growth by Metal Etching on Ru (0001)

Low-energy electron microscopy (LEEM) reveals a new mode of graphene growth on Ru(0001) in which Ru atoms from a step edge are injected under a growing graphene sheet. The injected atoms can form under-graphene islands, or incorporate into the topmost Ru layer, thereby increasing its density and forming dislocation networks. Density functional calculations imply that Ru islands nucleated between the graphene layer and the substrate are energetically stable; scanning tunneling microscopy (STM) reveals that dislocation networks exist near step edges.
Date: September 14, 2009
Creator: Loginova, Elena; Maier, Sabine; Stass, Ingeborg; Bartelt, Norman; Feibelman, Peter; Salmeron, Miquel et al.
Object Type: Article
System: The UNT Digital Library
Monodisperse metal nanoparticle catalysts on silica mesoporous supports: synthesis, characterizations, and catalytic reactions (open access)

Monodisperse metal nanoparticle catalysts on silica mesoporous supports: synthesis, characterizations, and catalytic reactions

The design of high performance catalyst achieving near 100% product selectivity at maximum activity is one of the most important goals in the modern catalytic science research. To this end, the preparation of model catalysts whose catalytic performances can be predicted in a systematic and rational manner is of significant importance, which thereby allows understanding of the molecular ingredients affecting the catalytic performances. We have designed novel 3-dimensional (3D) high surface area model catalysts by the integration of colloidal metal nanoparticles and mesoporous silica supports. Monodisperse colloidal metal NPs with controllable size and shape were synthesized using dendrimers, polymers, or surfactants as the surface stabilizers. The size of Pt, and Rh nanoparticles can be varied from sub 1 nm to 15 nm, while the shape of Pt can be controlled to cube, cuboctahedron, and octahedron. The 3D model catalysts were generated by the incorporation of metal nanoparticles into the pores of mesoporous silica supports via two methods: capillary inclusion (CI) and nanoparticle encapsulation (NE). The former method relies on the sonication-induced inclusion of metal nanoparticles into the pores of mesoporous silica, whereas the latter is performed by the encapsulation of metal nanoparticles during the hydrothermal synthesis of mesoporous silica. The …
Date: September 14, 2009
Creator: Somorjai, G.A.
Object Type: Book
System: The UNT Digital Library
Observation of Magnetocoriolis Waves in a Liquid Metal Taylor-Couette Experiment (open access)

Observation of Magnetocoriolis Waves in a Liquid Metal Taylor-Couette Experiment

The first observation of fast and slow magnetocoriolis (MC) waves in a laboratory experiment is reported. Rotating nonaxisymmetric modes arising from a magnetized turbulent Taylor-Couette flow of liquid metal are identified as the fast and slow MC waves by the dependence of the rotation frequency on the applied field strength. The observed slow MC wave is marginally damped but will become destabilized by the magnetorotational instability with a modest increase in rotation rate.
Date: September 14, 2009
Creator: M.D. Nornberg, H. Ji, E. Schartman, A. Roach, and J. Goodman
Object Type: Report
System: The UNT Digital Library
Oxidation of Mercury in Products of Coal Combustion (open access)

Oxidation of Mercury in Products of Coal Combustion

Laboratory measurements of mercury oxidation during selective catalytic reduction (SCR) of nitric oxide, simulation of pilot-scale measurements of mercury oxidation and adsorption by unburned carbon and fly ash, and synthesis of new materials for simultaneous oxidation and adsorption of mercury, were performed in support of the development of technology for control of mercury emissions from coal-fired boilers and furnaces. Conversion of gas-phase mercury from the elemental state to water-soluble oxidized form (HgCl{sub 2}) enables removal of mercury during wet flue gas desulfurization. The increase in mercury oxidation in a monolithic V{sub 2}O{sub 5}-WO{sub 3}/TiO{sub 2} SCR catalyst with increasing HCl at low levels of HCl (< 10 ppmv) and decrease in mercury oxidation with increasing NH{sub 3}/NO ratio during SCR were consistent with results of previous work by others. The most significant finding of the present work was the inhibition of mercury oxidation in the presence of CO during SCR of NO at low levels of HCl. In the presence of 2 ppmv HCl, expected in combustion products from some Powder River Basin coals, an increase in CO from 0 to 50 ppmv reduced the extent of mercury oxidation from 24 {+-} 3 to 1 {+-} 4%. Further increase in …
Date: September 14, 2009
Creator: Walsh, Peter; Tong, Giang; Bhopatkar, Neeles; Gale, Thomas; Blankenship, George; Ingram, Conrad et al.
Object Type: Report
System: The UNT Digital Library
Quality and Performance of LED Flashlights in Kenya: Common End User Preferences and Complaints (open access)

Quality and Performance of LED Flashlights in Kenya: Common End User Preferences and Complaints

Flashlights that use LED technology have quickly emerged as the dominant source of portable lighting in Kenya. While flashlights do not normally provide a substitute for kerosene and other highly inefficient fuels, they are an important early manifestation of LED lighting in the developing world that can serve as a platform - or deterrent - to the diffusion of the technology into the broader off-grid lighting market. The lead acid batteries embedded in flashlights also represent an important source of hazardous waste, and flashlight durability is thus an important determinant of the rate of waste disposal. Low-cost LED flashlights with prices from $1 to $4 are now widely available in shops and markets throughout Kenya. The increased penetration of LED technology in the flashlight market is significant, as over half of all Kenyan households report owning a flashlight (Kamfor, 2002). While this shift from conventional incandescent technology to modern LEDs may appear to be a promising development, end users that our research team interviewed expressed a number of complaints about the quality and performance of these new flashlights. This raises concerns about the interests of low-income flashlight users, and it may also indicate the onset of a broader market spoiling …
Date: September 14, 2009
Creator: Tracy, Jenny; Jacobson, Arne & Mills, Evan
Object Type: Report
System: The UNT Digital Library
Transmittal of the Calculation Package that Supports the Analysis of Performance of the Environmental Management Waste Management Facility Oak Ridge, Tennessee (Based 5-Cell Design Issued 8/14/09) (open access)

Transmittal of the Calculation Package that Supports the Analysis of Performance of the Environmental Management Waste Management Facility Oak Ridge, Tennessee (Based 5-Cell Design Issued 8/14/09)

This document presents the results of an assessment of the performance of a build-out of the Environmental Management Waste Management Facility (EMWMF). The EMWMF configuration that was assessed includes the as-constructed Cells 1 through 4, with a groundwater underdrain that was installed beneath Cell 3 during the winter of 2003-2004, and Cell 5, whose proposed design is an Addendum to Remedial Design Report for the Disposal of Oak Ridge Reservation Comprehensive Environmental Response, Compensation, and Liability Act of 1980 Waste, Oak Ridge, Tennessee, DOE/OR/01-1873&D2/A5/R1. The total capacity of the EMWMF with 5 cells is about 1.7 million cubic yards. This assessment was conducted to determine the conditions under which the approved Waste Acceptance Criteria (WAC) for the EMWMF found in the Attainment Plan for Risk/Toxicity-Based Waste Acceptance Criteria at the Oak Ridge Reservation, Oak Ridge, Tennessee [U.S. Department of Energy (DOE) 2001a], as revised for constituents added up to October 2008, would remain protective of public health and safety for a five-cell disposal facility. For consistency, the methods of analyses and the exposure scenario used to predict the performance of a five-cell disposal facility were identical to those used in the Remedial Investigation and Feasibility Study (RI/FS) and its addendum …
Date: September 14, 2009
Creator: Williams, M. J.
Object Type: Report
System: The UNT Digital Library
DEVELOPMENT OF A NEW TYPE A(F)RADIOACTIVE MATERIAL PACKAGING FOR THE DEPARTMENT OF ENERGY (open access)

DEVELOPMENT OF A NEW TYPE A(F)RADIOACTIVE MATERIAL PACKAGING FOR THE DEPARTMENT OF ENERGY

In a coordinated effort, the Department of Transportation (DOT) and Nuclear Regulatory Commission (NRC) proposed the elimination of the Specification Packaging from 49 CFR 173.[1] In accordance with the Federal Register, issued on October 1, 2004, new fabrication of Specification Packages would no longer be authorized. In accordance with the NRC final rulemaking published January 26, 2004, Specification Packagings are mandated by law to be removed from service no later than October 1, 2008. This coordinated effort and resulting rulemaking initiated a planned phase out of Specification Type B and Type A fissile (F) material transportation packages within the Department of Energy (DOE) and its subcontractors. One of the Specification Packages affected by this regulatory change is the UN1A2 Specification Package, per DOT 49 CFR 173.417(a)(6). To maintain continuing shipments of DOE materials currently transported in UN1A2 Specification Package after the existing authorization expires, a replacement Type A(F) material packaging design is under development by the Savannah River National Laboratory. This paper presents a summary of the prototype design effort and testing of the new Type A(F) Package development for the DOE. This paper discusses the progress made in the development of a Type A Fissile Packaging to replace the …
Date: September 14, 2008
Creator: Blanton, P. & Eberl, K.
Object Type: Article
System: The UNT Digital Library
DEVELOPMENT OF THE BULK TRITIUM SHIPPING PACKAGING (open access)

DEVELOPMENT OF THE BULK TRITIUM SHIPPING PACKAGING

A new radioactive shipping packaging for transporting bulk quantities of tritium, the Bulk Tritium Shipping Package (BTSP), has been designed for the Department of Energy (DOE) as a replacement for a package designed in the early 1970s. This paper summarizes significant design features and describes how the design satisfies the regulatory safety requirements of the Code of Federal Regulations and the International Atomic Energy Agency. The BTSP design incorporates many improvements over its predecessor by implementing improved testing, handling, and maintenance capabilities, while improving manufacturability and incorporating new engineered materials. This paper also discusses the results from testing of the BTSP to 10 CFR 71 Normal Conditions of Transport and Hypothetical Accident Condition events. The programmatic need of the Department of Energy (DOE) to ship bulk quantities of tritium has been satisfied since the late 1970s by the UC-609 shipping package. The current Certificate of Conformance for the UC-609, USA/9932/B(U) (DOE), will expire in late 2011. Since the UC-609 was not designed to meet current regulatory requirements, it will not be recertified and thereby necessitates a replacement Type B shipping package for continued DOE tritium shipments in the future. A replacement tritium packaging called the Bulk Tritium Shipping Package (BTSP) …
Date: September 14, 2008
Creator: Blanton, P. & Eberl, K.
Object Type: Article
System: The UNT Digital Library
An Efficient LED System-in-Module for General Lighting Applications (open access)

An Efficient LED System-in-Module for General Lighting Applications

The objective of the project was to realize an LED-based lighting technology platform for general illumination, starting with LED chips, and integrating the necessary technologies to make compact, user-friendly, high-efficiency, energy-saving sources of controlled white (or variable-colored) light. The project is to build the system around the LEDs, and not to work on the LEDs themselves, in order that working products can be introduced soon after the LEDs reach suitable efficiency for mass-production of high-power light sources for general illumination. Because the light sources are intended for general illumination, color must be accurately maintained, requiring feedback control in the electronics. The project objective has been realized and screw base demonstrators, based on the technology developed in the project, have been built.
Date: September 14, 2008
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Elucidation of Polymer and Polymer Composite Behavior Molding Operation (open access)

Elucidation of Polymer and Polymer Composite Behavior Molding Operation

None
Date: September 14, 2008
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Final report on work for Center for Gyrokinetic Particle Simulation of Turbulent Transport in Burning Plasmas — Tools for Improved Data Logistics (open access)

Final report on work for Center for Gyrokinetic Particle Simulation of Turbulent Transport in Burning Plasmas — Tools for Improved Data Logistics

This project focused on the use of Logistical Networking technology to address the challenges involved in rapid sharing of data from the the Center's gyrokinetic particle simulations, which can be on the order of terabytes per time step, among researchers at a number of geographically distributed locations. There is a great need to manage data on this scale in a flexible manner, with simulation code, file system, database and visualization functions requiring access. The project used distributed data management infrastructure based on Logistical Networking technology to address these issues in a way that maximized interoperability and achieved the levels of performance the required by the Center's application community. The work focused on the development and deployment of software tools and infrastructure for the storage and distribution of terascale datasets generated by simulations running at the National Center for Computational Science at Oak Ridge National Laboratory.
Date: September 14, 2008
Creator: Beck, Micah
Object Type: Report
System: The UNT Digital Library
Final Technical Report (open access)

Final Technical Report

Over the past year, our group here at the University of Texas has continued to focus primarily on analysis of data from the Sudbury Neutrino Observatory (SNO), in particular on a push to lower the energy threshold used in solar neutrino analyses and on a search for short time-scale astrophysical phenomena in the neutrino data set. We have in addition begun R and D and simulation work on a new direct search for dark matter as part of the DEAP/CLEAN collaboration, as well as an effort associated with work on a new experiment using the existing SNO detector (SNO+). Lastly, we have also been doing some very early studies of an experiment to measure the neutrino mass using the beta decay of cold tritium atoms. Our work on SNO has focused primarily on making a low-threshold spectral measurement of the flux of {sup 8}B solar neutrinos. The work forms the bulk of graduate student Stan Seibert's PhD thesis. Nearly all systematic uncertainties associated with the analysis have now been measured, in particular the dominant uncertainties such as energy scale and resolution, and the uncertainty on SNO's 'isotropy' parameter used to distinguish electrons, neutrons, and radioactive backgrounds. It is now clear …
Date: September 14, 2008
Creator: Klein, Joshua R.
Object Type: Report
System: The UNT Digital Library
Flooding Experiments and Modeling for Improved Reactor Safety (open access)

Flooding Experiments and Modeling for Improved Reactor Safety

Countercurrent two-phase flow and “flooding” phenomena in light water reactor systems are being investigated experimentally and analytically to improve reactor safety of current and future reactors. The aspects that will be better clarified are the effects of condensation and tube inclination on flooding in large diameter tubes. The current project aims to improve the level of understanding of flooding mechanisms and to develop an analysis model for more accurate evaluations of flooding in the pressurizer surge line of a Pressurized Water Reactor (PWR). Interest in flooding has recently increased because Countercurrent Flow Limitation (CCFL) in the AP600 pressurizer surge line can affect the vessel refill rate following a small break LOCA and because analysis of hypothetical severe accidents with the current flooding models in reactor safety codes shows that these models represent the largest uncertainty in analysis of steam generator tube creep rupture. During a hypothetical station blackout without auxiliary feedwater recovery, should the hot leg become voided, the pressurizer liquid will drain to the hot leg and flooding may occur in the surge line. The flooding model heavily influences the pressurizer emptying rate and the potential for surge line structural failure due to overheating and creep rupture. The air-water …
Date: September 14, 2008
Creator: Solmos, M., Hogan, K.J., VIerow, K.
Object Type: Article
System: The UNT Digital Library
High Efficiency Integrated Space Conditioning, Water Heating and Air Distribution System for HUD-Code Manufactured Housing (open access)

High Efficiency Integrated Space Conditioning, Water Heating and Air Distribution System for HUD-Code Manufactured Housing

Recognizing the need for new space conditioning and water heating systems for manufactured housing, DeLima Associates assembled a team to develop a space conditioning system that would enhance comfort conditions while also reducing energy usage at the systems level. The product, Comboflair® was defined as a result of a needs analysis of project sponsors and industry stakeholders. An integrated system would be developed that would combine a packaged airconditioning system with a small-duct, high-velocity air distribution system. In its basic configuration, the source for space heating would be a gas water heater. The complete system would be installed at the manufactured home factory and would require no site installation work at the homesite as is now required with conventional split-system air conditioners. Several prototypes were fabricated and tested before a field test unit was completed in October 2005. The Comboflair® system, complete with ductwork, was installed in a 1,984 square feet, double-wide manufactured home built by Palm Harbor Homes in Austin, TX. After the home was transported and installed at a Palm Harbor dealer lot in Austin, TX, a data acquisition system was installed for remote data collection. Over 60 parameters were continuously monitored and measurements were transmitted to a …
Date: September 14, 2008
Creator: DeLima, Henry; Akin, Joe & Pietsch, Joseph
Object Type: Report
System: The UNT Digital Library
Microbial transformations of uranium in wastes and implication on its mobility (open access)

Microbial transformations of uranium in wastes and implication on its mobility

Uranium exists in several chemical forms in mining and mill tailings and in nuclear and weapons production wastes. Under appropriate conditions, microorganisms can affect the stability and mobility of U in wastes by altering the chemical speciation, solubility and sorption properties and thus could increase or decrease the concentrations of U in solution and the bioavailability. Dissolution or immobilization of U is brought about by direct enzymatic action or indirect nonenzymatic action of microorganisms. Although the physical, chemical, and geochemical processes affecting dissolution, precipitation, and mobilization of U have been extensively investigated, we have only limited information on the mechanisms of microbial transformations of various chemical forms of U in the presence of electron donors and acceptors.
Date: September 14, 2008
Creator: Suzuki, Y.; Nankawa, T.; Ozaki, T.; Ohnuki, T.; Francis, A. J.; Enokida, Y. et al.
Object Type: Article
System: The UNT Digital Library
Calculation of the Thermal Footprint of Resonant Magnetic Perturbations in DIII-D (open access)

Calculation of the Thermal Footprint of Resonant Magnetic Perturbations in DIII-D

The effect of resonant magnetic perturbations on heat transport in DIII-D H-mode plasmas has been calculated by combining the TRIP3D field-line tracing code with the E3D two-fluid transport code. Simulations show that the divertor heat flux distribution becomes non-axisymmetric because heat flux is efficiently guided to the divertor along the three-dimensional invariant manifolds of the magnetic field. Calculations demonstrate that heat flux is spread over a wider area of the divertor target, thereby reducing the peak heat flux delivered during steady-state operation. Filtered optical cameras have observed non-axisymmetric particle fluxes at the strike-point and Langmuir probes have observed non-axisymmetric floating potentials. On the other hand, the predicted magnitude of stochastic thermal transport is too large to match the pedestal plasma profiles measured by Thomson scattering and charge exchange recombination spectroscopy. The Braginskii thermal conductivity overestimates the expected heat transport in the pedestal because the mean free path is longer than estimates of the parallel thermal correlation length, and collisionless transport models are probably required for accurate description. However, even the collisionless estimates for electron thermal transport are too large by one to two orders of magnitude. Thus, it is likely that another mechanism such as rotational screening of resonant perturbations …
Date: September 14, 2007
Creator: Joseph, I; Evans, T; Moyer, R; Fenstermacher, M; Groth, M; Kasilov, S et al.
Object Type: Article
System: The UNT Digital Library
Improved Gamma Bang Time Measurements on Omega and Implications for the National Ignition Facility (open access)

Improved Gamma Bang Time Measurements on Omega and Implications for the National Ignition Facility

The time of peak fusion reactivity with respect to the impingement of laser light on an ICF capsule is known as Bang Time (BT). This is an essential parameter in the understanding of ICF implosions. Traditionally, BT has been determined through temporal measurements of 14 MeV fusion neutrons. Because the neutron energy spectrum is Doppler broadened, the detector must be positioned close to target-chamber center in order to minimize the neutron temporal spreading which can compromise such a measurement. Fusion gammas, on the other hand, are not subject to temporal spreading, making proximity of the detector to the source a lesser concern. However, the low branching ratio for DT fusion reactions producing gammas ({approx}1e-4) presents detector sensitivity challenges.
Date: September 14, 2007
Creator: Miller, Edward K.; Hermann, H. W.; Caldwell, S. E.; Evans, S. C.; Mack, J. M.; Shanch, P. et al.
Object Type: Article
System: The UNT Digital Library
Line Emission from Optically Thick RelativisticAccretion Tori (open access)

Line Emission from Optically Thick RelativisticAccretion Tori

We calculate line emission from relativistic accretion tori around Kerr black holes and investigate how the line profiles depend on the viewing inclination, spin of the central black hole, parameters describing the shape of the tori, and spatial distribution of line emissivity on the torus surface. We also compare the lines with those from thin accretion disks. Our calculations show that lines from tori and lines from thin disks share several common features. In particular, at low and moderate viewing inclination angles they both have asymmetric double-peaked profiles with a tall, sharp blue peak and a shorter red peak which has an extensive red wing. At high viewing inclination angles they both have very broad, asymmetric lines which can be roughly considered as single-peaked. Torus and disk lines may show very different red and blue line wings, but the differences are due to the models for relativistic tori and disks having differing inner boundary radii. Self-eclipse and lensing play some role in shaping the torus lines, but they are effective only at high inclination angles. If inner and outer radii of an accretion torus are the same as those of an accretion disk, their line profiles show substantial differences only …
Date: September 14, 2007
Creator: Fuerst, Steven V.; /KIPAC, Menlo Park /Mullard Space Sci. Lab.; Wu, Kinwah & Lab., /Mullard Space Sci.
Object Type: Article
System: The UNT Digital Library
LLNL Facility Screening Report (SCR) for B362 (open access)

LLNL Facility Screening Report (SCR) for B362

None
Date: September 14, 2007
Creator: Cooper, G
Object Type: Report
System: The UNT Digital Library
Observation of the Semileptonic Decays B to D*taunu and Evidence for B to D tau nu (open access)

Observation of the Semileptonic Decays B to D*taunu and Evidence for B to D tau nu

We present measurements of the semileptonic decays B{sup -} {yields} D{sup 0}{tau}{sup -}{bar {nu}}{sub {tau}}, B{sup -} {yields} D{sup *0}{tau}{sup -}{bar {nu}}{sub {tau}}, B{sup -} {yields} D{sup +}{tau}{sup -}{bar {nu}}{sub {tau}}, and B{sup -} {yields} D{sup *+}{tau}{sup -}{bar {nu}}{sub {tau}}, which are potentially sensitive to non-Standard Model amplitudes, The data sample comprises 232 x 10{sup 6} {Upsilon}(4s) {yields} B{bar B} decays collected with the BABAR detector. From a combined fit to B{sup -} and {bar B}{sup 0} channels, we obtain the branching fractions {beta}(B {yields} D{sub {tau}}{sup -}{bar {nu}}{sub {tau}}) = (0:86 {+-} 0:24 {+-} 0:11 {+-} 0:06)% and {beta}(B {yields} D*{tau}{sup -}{bar {nu}}{sub {tau}}) = (1:62 {+-} 0:31 {+-} 0:10 {+-} 0:05)% (normalized for the {bar B}{sup 0}), , where the uncertainties are statistical, systematic, and normalization-mode-related.
Date: September 14, 2007
Creator: B., Aubert
Object Type: Article
System: The UNT Digital Library
Searching for Inflation in Simple String TheoryModels: An Sstrophysical Perspective (open access)

Searching for Inflation in Simple String TheoryModels: An Sstrophysical Perspective

None
Date: September 14, 2007
Creator: Hertzberg, Mark P.; Tegmark, Max; /MIT; Kachru, Shamit; /Stanford U., Phys. Dept. /SLAC; Shelton, Jessie et al.
Object Type: Article
System: The UNT Digital Library
The Sloan Digital Sky Survey-II Supernova Survey:Search Algorithm and Follow-up Observations (open access)

The Sloan Digital Sky Survey-II Supernova Survey:Search Algorithm and Follow-up Observations

The Sloan Digital Sky Survey-II Supernova Survey has identified a large number of new transient sources in a 300 deg2 region along the celestial equator during its first two seasons of a three-season campaign. Multi-band (ugriz) light curves were measured for most of the sources, which include solar system objects, Galactic variable stars, active galactic nuclei, supernovae (SNe), and other astronomical transients. The imaging survey is augmented by an extensive spectroscopic follow-up program to identify SNe, measure their redshifts, and study the physical conditions of the explosions and their environment through spectroscopic diagnostics. During the survey, light curves are rapidly evaluated to provide an initial photometric type of the SNe, and a selected sample of sources are targeted for spectroscopic observations. In the first two seasons, 476 sources were selected for spectroscopic observations, of which 403 were identified as SNe. For the Type Ia SNe, the main driver for the Survey, our photometric typing and targeting efficiency is 90%. Only 6% of the photometric SN Ia candidates were spectroscopically classified as non-SN Ia instead, and the remaining 4% resulted in low signal-to-noise, unclassified spectra. This paper describes the search algorithm and the software, and the real-time processing of the SDSS …
Date: September 14, 2007
Creator: Sako, Masao; Bassett, Bruce; Becker, Andrew; Cinabro, David; DeJongh, Don Frederic; Depoy, D. L. et al.
Object Type: Article
System: The UNT Digital Library