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The 8 O'Clock Arc: A Serendipitous Discovery of a Strongly Lensed Lyman Break Galaxy in the SDSS DR4 Imaging Data (open access)

The 8 O'Clock Arc: A Serendipitous Discovery of a Strongly Lensed Lyman Break Galaxy in the SDSS DR4 Imaging Data

We report on the serendipitous discovery of the brightest Lyman Break Galaxy (LBG) currently known, a galaxy at z = 2.73 that is being strongly lensed by the z = 0.38 Luminous Red Galaxy (LRG) SDSS J002240.91+143110.4. The arc of this gravitational lens system, which we have dubbed the ''8 o'clock arc'' due to its time of discovery, was initially identified in the imaging data of the Sloan Digital Sky Survey Data Release 4 (SDSS DR4); followup observations on the Astrophysical Research Consortium (ARC) 3.5m telescope at Apache Point Observatory confirmed the lensing nature of this system and led to the identification of the arc's spectrum as that of an LBG. The arc has a spectrum and a redshift remarkably similar to those of the previous record-holder for brightest LBG (MS 1512-cB58, a.k.a ''cB58''), but, with an estimated total magnitude of (g,r,i) = (20.0,19.2,19.0) and surface brightness of ({mu}{sub g}, {mu}{sub r}, {mu}{sub i}) = (23.3, 22.5, 22.3) mag arcsec{sup -2}, the 8 o'clock arc is thrice as bright. The 8 o'clock arc, which consists of three lensed images of the LBG, is 162{sup o}(9.6'') long and has a length-to-width ratio of 6:1. A fourth image of the LBG--a counter-image--can …
Date: November 1, 2006
Creator: Allam, Sahar S.; Tucker, Douglas L.; Lin, Huan; Diehl, H. Thomas; Annis, James; Buckley-Geer, Elizabeth J. et al.
System: The UNT Digital Library
100,000-Mile Evaluation of Transit Buses Operated on Biodiesel Blends (B20) (open access)

100,000-Mile Evaluation of Transit Buses Operated on Biodiesel Blends (B20)

Evaluates the emissions, fuel economy, and maintenance of five 40-foot transit buses operated on B20 compared to four on petroleum diesel.
Date: November 1, 2006
Creator: Proc, K.; Barnitt, R.; Hayes, R. R.; Ratcliff, M.; McCormick, R. L.; Ha, L. et al.
System: The UNT Digital Library
Addressing the workforce pipeline challenge (open access)

Addressing the workforce pipeline challenge

A secure and affordable energy supply is essential for achieving U.S. national security, in continuing U.S. prosperity and in laying the foundations to enable future economic growth. To meet this goal the next generation energy workforce in the U.S., in particular those needed to support instrumentation, controls and advanced operations and maintenance, is a critical element. The workforce is aging and a new workforce pipeline, to support both current generation and new build has yet to be established. The paper reviews the challenges and some actions being taken to address this need.
Date: November 1, 2006
Creator: Bond, Leonard; Kostelnik, Kevin & Holman, Richard
System: The UNT Digital Library
Advances in Acid Concentration Membrane Technology for the Sulfur-Iodine Thermochemical Cycle (open access)

Advances in Acid Concentration Membrane Technology for the Sulfur-Iodine Thermochemical Cycle

One of the most promising cycles for the thermochemical generation of hydrogen is the Sulfur-Iodine (S-I) process, where aqueous HI is thermochemically decomposed into H2 and I2 at approximately 350 degrees Celsius. Regeneration of HI is accomplished by the Bunsen reaction (reaction of SO2, water, and iodine to generate H2SO4 and HI). Furthermore, SO2 is regenerated from the decomposition of H2SO4 at 850 degrees Celsius yielding the SO2 as well as O2. Thus, the cycle actually consists of two concurrent oxidation-reduction loops. As HI is regenerated, co-produced H2SO4 must be separated so that each may be decomposed. Current flowsheets employ a large amount (~83 mol% of the entire mixture) of elemental I2 to cause the HI and the H2SO4 to separate into two phases. To aid in the isolation of HI, which is directly decomposed into hydrogen, water and iodine must be removed. Separation of iodine is facilitated by removal of water. Sulfuric acid concentration is also required to facilitate feed recycling to the sulfuric acid decomposer. Decomposition of the sulfuric acid is an equilibrium limited process that leaves a substantial portion of the acid requiring recycle. Distillation of water from sulfuric acid involves significant corrosion issues at the liquid-vapor …
Date: November 1, 2006
Creator: Stewart, Frederick F. & Orme, Christopher J.
System: The UNT Digital Library
Application of a Sweating Manikin Controlled by a Human Physiological Model and Lessons Learned (open access)

Application of a Sweating Manikin Controlled by a Human Physiological Model and Lessons Learned

Discusses two applications of NREL's suite of thermal comfort tools: one to assess impact of an automotive ventilated seat on comfort and fuel economy, and another to evaluate liquid cooling garments for NASA spacesuits.
Date: November 1, 2006
Creator: Rugh, J. & Lustbader, J.
System: The UNT Digital Library
Application of a Swelling/Shrinkage Model for Analysis of Reservoir Performance at a Field Site (open access)

Application of a Swelling/Shrinkage Model for Analysis of Reservoir Performance at a Field Site

This report talks about Application of a Swelling/Shrinkage Model for Analysis of Reservoir Performance at a Field Site
Date: November 1, 2006
Creator: Siriwardane, H. & Smith, D. H.
System: The UNT Digital Library
Battery Thermal Management System Design Modeling (open access)

Battery Thermal Management System Design Modeling

Looks at the impact of cooling strategies with air and both direct and indirect liquid cooling for battery thermal management.
Date: November 1, 2006
Creator: Pesaran, A. & Kim, G. H.
System: The UNT Digital Library
Beam diagnostics, collimation, injection/extraction, targetry, accidents and commissioning: Working group C&G summary report (open access)

Beam diagnostics, collimation, injection/extraction, targetry, accidents and commissioning: Working group C&G summary report

The performance of accelerators with high beam power or high stored beam energy is strongly dependent on the way the beam is handled, how beam parameters are measured and how the machine is commissioned. Two corresponding working groups have been organized for the Workshop: group C ''Beam diagnostics, collimation, injection/extraction and targetry'' and group G ''Commissioning strategies and procedures''. It has been realized that the issues to be discussed in these groups are interlaced with the participants involved and interested in the above topics, with an extremely important subject of beam-induced accidents as additional topic. Therefore, we have decided to combine the group sessions as well as this summary report. Status, performance and outstanding issues of each the topic are described in the sections below, with additional observations and proposals by the joint group at the end.
Date: November 1, 2006
Creator: Mokhov, N. V.; Hasegawa, K.; Henderson, S.; Schmidt, R.; Tomizawa, M. & Wittenburg, K.
System: The UNT Digital Library
Beam-induced damage to the Tevatron components and what has been done about it (open access)

Beam-induced damage to the Tevatron components and what has been done about it

A beam-induced damage to the Tevatron collimators happened in December 2003 was induced by a failure in the CDF Roman Pot detector positioning during the collider run. Possible scenarios of this failure resulted in an excessive halo generation and superconducting magnet quench have been studied via realistic simulations using the STRUCT and MARS14 codes. It is shown that the interaction of a misbehaved proton beam with the collimators result in a rapid local heating and a possible damage. A detailed consideration is given to the ablation process for the collimator material taking place in high vacuum. It is shown that ablation of tungsten (primary collimator) and stainless steel (secondary collimator) jaws results in creation of a groove in the jaw surface as was observed after the December's accident. The actions undertaken to avoid such an accident in future are described in detail.
Date: November 1, 2006
Creator: Mokhov, N. V.; Czarapata, P. C.; Drozhdin, A. I.; Still, D. A.; /Fermilab; Samulyak, R. V. et al.
System: The UNT Digital Library
Can Astrophysical Gamma Ray Sources Mimic Dark Matter Annihilation in Galactic Satellites? (open access)

Can Astrophysical Gamma Ray Sources Mimic Dark Matter Annihilation in Galactic Satellites?

The nature of the cosmic dark matter is unknown. The most compelling hypothesis is that dark matter consists of weakly interacting massive particles (WIMPs) in the 100 GeV mass range. Such particles would annihilate in the galactic halo, producing high-energy gamma rays which might be detectable in gamma ray telescopes such as the GLAST satellite. We investigate the ability of GLAST to distinguish between the WIMP annihilation spectrum and the spectrum of known astrophysical source classes. Focusing on the emission from the galactic satellite halos predicted by the cold dark matter model, we find that the WIMP gamma-ray spectrum is unique; the separation from known source classes can be done in a convincing way. We discuss the follow-up of possible WIMP sources with Imaging Atmospheric Cerenkov Telescopes. Finally we discuss the impact that Large Hadron Collider data might have on the study of galactic dark matter.
Date: November 1, 2006
Creator: Baltz, Edward A.; /KIPAC, Menlo Park; Taylor, James E.; U., /Waterloo; Wai, Lawrence L. & /KIPAC, Menlo Park
System: The UNT Digital Library
CAPE-OPEN Integration for Advanced Process Engineering Co-Simulation (open access)

CAPE-OPEN Integration for Advanced Process Engineering Co-Simulation

This paper highlights the use of the CAPE-OPEN (CO) standard interfaces in the Advanced Process Engineering Co-Simulator (APECS) developed at the National Energy Technology Laboratory (NETL). The APECS system uses the CO unit operation, thermodynamic, and reaction interfaces to provide its plug-and-play co-simulation capabilities, including the integration of process simulation with computational fluid dynamics (CFD) simulation. APECS also relies heavily on the use of a CO COM/CORBA bridge for running process/CFD co-simulations on multiple operating systems. For process optimization in the face of multiple and some time conflicting objectives, APECS offers stochastic modeling and multi-objective optimization capabilities developed to comply with the CO software standard. At NETL, system analysts are applying APECS to a wide variety of advanced power generation systems, ranging from small fuel cell systems to commercial-scale power plants including the coal-fired, gasification-based FutureGen power and hydrogen production plant.
Date: November 1, 2006
Creator: Zitney, S. E.
System: The UNT Digital Library
CDF Run II Monte-Carlo tunes (open access)

CDF Run II Monte-Carlo tunes

Several CDF Run 2 PYTHIA 6.2 tunes (with multiple parton interactions) are presented and compared with HERWIG (without multiple parton interactions) and with the ATLAS PYTHIA tune (with multiple parton interactions). Predictions are made for the ''underlying event'' in high p{sub T} jet production and in Drell-Yan lepton-pair production at the Tevatron and the LHC.
Date: November 1, 2006
Creator: Field, Rick
System: The UNT Digital Library
Cluster Dynamics in a Circulating Fluidized Bed (open access)

Cluster Dynamics in a Circulating Fluidized Bed

A common hydrodynamic feature in industrial scale circulating fluidized beds is the presence of clusters. The continuous formation and destruction of clusters strongly influences particle hold-up, pressure drop, heat transfer at the wall, and mixing. In this paper fiber optic data is analyzed using discrete wavelet analysis to characterize the dynamic behavior of clusters. Five radial positions at three different axial locations under five different operating were analyzed using discrete wavelets. Results are summarized with respect to cluster size and frequency.
Date: November 1, 2006
Creator: Guenther, C. P. & Breault, R. W.
System: The UNT Digital Library
Coherent Control of Optically Generated and Detected Picosecond Surface Acoustic Phonons (open access)

Coherent Control of Optically Generated and Detected Picosecond Surface Acoustic Phonons

Coherent control of elementary optical excitations is a key issue in ultrafast materials science. Manipulation of electronic and vibronic excitations in solids as well as chemical and biological systems on ultrafast time scales has attracted a great deal of attention recently. In semiconductors, coherent control of vibronic excitations has been demonstrated for bulk acoustic and optical phonons generated in superlattice structures. The bandwidth of these approaches is typically fully utilized by employing a 1-D geometry where the laser spot size is much larger than the superlattice repeat length. In this presentation we demonstrate coherent control of optically generated picosecond surface acoustic waves using sub-optical wavelength absorption gratings. The generation and detection characteristics of two material systems are investigated (aluminum absorption gratings on Si and GaAs substrates).
Date: November 1, 2006
Creator: Hurley, David H.
System: The UNT Digital Library
Computational Flow Predictions for the Lower Plenum of a High-Temperature, Gas-Cooled Reactor (open access)

Computational Flow Predictions for the Lower Plenum of a High-Temperature, Gas-Cooled Reactor

Advanced gas-cooled reactors offer the potential advantage of higher efficiency and enhanced safety over present day nuclear reactors. Accurate simulation models of these Generation IV reactors are necessary for design and licensing. One design under consideration by the Very High Temperature Reactor (VHTR) program is a modular, prismatic gas-cooled reactor. In this reactor, the lower plenum region may experience locally high temperatures that can adversely impact the plant’s structural integrity. Since existing system analysis codes cannot capture the complex flow effects occurring in the lower plenum, computational fluid dynamics (CFD) codes are being employed to model these flows [1]. The goal of the present study is to validate the CFD calculations using experimental data.
Date: November 1, 2006
Creator: Guillen, Donna Post
System: The UNT Digital Library
Construction Safety Forecast for ITER (open access)

Construction Safety Forecast for ITER

The International Thermonuclear Experimental Reactor (ITER) project is poised to begin its construction activity. This paper gives an estimate of construction safety as if the experiment was being built in the United States. This estimate of construction injuries and potential fatalities serves as a useful forecast of what can be expected for construction of such a major facility in any country. These data should be considered by the ITER International Team as it plans for safety during the construction phase. Based on average U.S. construction rates, ITER may expect a lost workday case rate of < 4.0 and a fatality count of 0.5 to 0.9 persons per year.
Date: November 1, 2006
Creator: Cadwallader, Lee Charles
System: The UNT Digital Library
Corrosion Performance of Ferritic Steel for SOFC Interconnect Applications (open access)

Corrosion Performance of Ferritic Steel for SOFC Interconnect Applications

Ferritic stainless steels have been identified as potential candidates for interconnects in planar-type solid oxide fuel cells (SOFC) operating below 800ºC. Crofer 22 APU was selected for this study. It was studied under simulated SOFC-interconnect dual environment conditions with humidified air on one side of the sample and humidified hydrogen on the other side at 750ºC. The surfaces of the oxidized samples were studied by scanning electron microscopy (SEM) equipped with microanalytical capabilities. X-ray diffraction (XRD) analysis was also used in this study.
Date: November 1, 2006
Creator: Ziomek-Moroz, M.; Holcomb, G. R.; Covino, B. S., Jr.; Bullard, S. J.; Jablonski, P. D. & Alman, D. E.
System: The UNT Digital Library
Cosmic microwave background and large-scale structure constraints on a simple quintessential inflation model (open access)

Cosmic microwave background and large-scale structure constraints on a simple quintessential inflation model

We derive constraints on a simple quintessential inflation model, based on a spontaneously broken {Phi}{sup 4} theory, imposed by the Wilkinson Microwave Anisotropy Probe three-year data (WMAP3) and by galaxy clustering results from the Sloan Digital Sky Survey (SDSS). We find that the scale of symmetry breaking must be larger than about 3 Planck masses in order for inflation to generate acceptable values of the scalar spectral index and of the tensor-to-scalar ratio. We also show that the resulting quintessence equation-of-state can evolve rapidly at recent times and hence can potentially be distinguished from a simple cosmological constant in this parameter regime.
Date: November 1, 2006
Creator: Rosenfeld, Rogerio; /Sao Paulo, IFT; Frieman, Joshua A. & /Fermilab /Chicago U., Astron. Astrophys. Ctr.
System: The UNT Digital Library
Cost-Benefit Analysis of Plug-in Hybrid Electric Vehicle Technology (open access)

Cost-Benefit Analysis of Plug-in Hybrid Electric Vehicle Technology

This paper presents a comparison of vehicle purchase and energy costs, and fuel-saving benefits of plug-in hybrid electric vehicles relative to hybrid electric and conventional vehicles.
Date: November 1, 2006
Creator: Simpson, A.
System: The UNT Digital Library
Coupled Thermal and Water Management in Polymer-Electrolyte FuelCells (open access)

Coupled Thermal and Water Management in Polymer-Electrolyte FuelCells

Thermal and water management are intricately coupled in polymer-electrolyte fuel cells. In this paper, we simulate fuel-cell performance and account for nonisothermal phenomena. The transport of water due to a temperature gradient and its associated effects on performance are described, with the increase of reactant dilution by the water-vapor partial pressure being the most dominant. In addition, simulations are undergone to find the optimum operating temperature and maximum power density as a function of external heat-transfer coefficient. The shape of the optimization curves and the magnitudes of the nonisothermal phenomena are also detailed and explained.
Date: November 1, 2006
Creator: Weber, Adam Z. & Newman, John
System: The UNT Digital Library
Curved track segment finding using Tiny Triplet Finder (TTF) (open access)

Curved track segment finding using Tiny Triplet Finder (TTF)

We describe the applications of a track segment recognition scheme called the Tiny Triplet Finder (TTF) that involves the grouping of three hits satisfying a constraint forming of a track segment. The TTF was originally developed solving straight track segment finding problem, however, it is also suitable in many curved track segment finding problems. The examples discussed in this document are among popular detector layouts in high-energy/nuclear physics experiments. Although it is not practical to find a universal recipe for arbitrary detector layouts, the method of the TTF application is illustrated via the discussion of the examples. Generally speaking, whenever the data item to be found in a pattern recognition problem contains two free parameters, and if the constraint connecting the measurements and the two free parameters has an approximate shift invariant property, the Tiny Triplet Finder can be used.
Date: November 1, 2006
Creator: Wu, Jin-Yuan; Wang, M.; Gottschalk, E.; Shi, Z. & /Fermilab
System: The UNT Digital Library
Diffraction at the Tevatron: CDF results (open access)

Diffraction at the Tevatron: CDF results

The diffractive program of the CDF Collaboration at the Fermilab Tevatron p{bar p} Collider is reviewed with emphasis on recent results from Run II at {radical}s = 1.96 TeV. Updated results on the x{sub B{sub j}} and Q{sup 2} dependence of the diffractive structure function obtained from dijet production, and on the slope parameter of the t-distribution of diffractive events as a function of Q{sup 2} in the range 1 GeV{sup 2} &lt; Q{sup 2} &lt; 10{sup 4} GeV{sup 2}, are presented and compared with theoretical expectations. Results on cross sections for exclusive dijet and diphoton production are also presented and used to calibrate theoretical estimates for exclusive Higgs production at the Large Hadron Collider.
Date: November 1, 2006
Creator: Goulianos, Konstantin
System: The UNT Digital Library
Dissolution testing of a metallic waste form in chloride brine (open access)

Dissolution testing of a metallic waste form in chloride brine

This paper is intended for publication in the peer-reviewed proceedings from the Scientific Basis for Nuclear Waste Management (at the Fall 2006 meeting of the Materials Research Society). The same material was presented in a 15-minute talk. Argonne National Laboratory has developed an electrometallurgical process for conditioning spent sodium-bonded metallic reactor fuel from the Experimental Breeder Reactor II (EBR-II). One waste stream from this process consists of a metal waste form (MWF) whose baseline composition is stainless steel alloyed with 15 wt% Zr (SS-15Zr) and whose microstructure is a eutectic intergrowth of iron solid solutions and Fe-Zr-Cr-Ni intermetallics. This paper reports scanning electron microscope (SEM) observations of corrosion products formed during static immersion tests in which coupons of surrogate MWF containing 10 wt% U (SS-15Zr-10U) were immersed in solutions with nominal pH values of 3 and 4 and 1000 ppm added chloride for 70 days at 50 °C. Although the majority of the surface areas of the coupons appear unchanged, linear areas with localized corrosion products apparently consisting of porous materials overlying corrosion-product-filled channels formed on both coupons, cross-cutting phase boundaries in the original eutectic microstructures. Many of the linear areas intersected the sample edge at notches present before the …
Date: November 1, 2006
Creator: Janney, Dawn E
System: The UNT Digital Library
Dynamic Programming Applied to Investigate Energy Management Strategies for a Plug-in HEV (open access)

Dynamic Programming Applied to Investigate Energy Management Strategies for a Plug-in HEV

This paper explores two basic plug-in hybrid electric vehicle energy management strategies: an electric vehicle centric control strategy and an engine-motor blended control strategy.
Date: November 1, 2006
Creator: P., O'Keefe. M. & Markel, T.
System: The UNT Digital Library