The chemical vapor deposition and properties of the boron-rich semiconductors B12As2 and B12P2 on 6H-SiC(0001) and silicon substrates were investigated. Crystalline, stoichiometric films were deposited between 1200 C and 1500 C using two types of reactants, hydrides (B2H6 and AsH3) for B12As2 and halides (BBr3 and PBr3) for B12P2. 6H-SiC proved to be the better substrate for B12As2 heteroepitaxy, in terms of the residual impurity concentrations. Films on Si substrates suffered from high concentrations of Si (up to 4at.%); in contrast, the Si and C concentrations in the B12As2 films deposited on 6H-SiC at 1300 C were at or below the detection limits of secondary ion mass spectrometry (SIMS). The deposition temperature was significant as films deposited at 1450 C contained high residual C and Si concentrations (>1020 cm-3), probably due to the decomposition of the substrate. The hydrogen concentration in all B12As2 films was relatively high, with a minimum concentration of 3x1019 cm-3 in undoped B12As2. SIMS measurements showed that the hydrogen concentration was directly proportional to and tracked the Si concentration, reaching values as high as 3 x 1020 cm-3. The structural properties of the B12As2 films were characterized by x-ray diffraction and transmission electron microscopy. The FWHM …

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Dielectric, adhesion-promoting, moisture barriers comprised of silicon oxynitride thin film materials (SiOxNy with various material stoichiometric compositions x,y) were applied to: 1) bare and pre-coated soda-lime silicate glass (coated with transparent conductive oxide SnO2:F and/or aluminum), and polymer substrates (polyethylene terephthalate, PET, or polyethylene napthalate, PEN); plus 2) pre- deposited photovoltaic (PV) cells and mini-modules consisting of amorphous silicon (a-Si) and copper indium gallium diselenide (CIGS) thin-film PV technologies. We used plasma enhanced chemical vapor deposition (PECVD) process with dilute silane, nitrogen, and nitrous oxide/oxygen gas mixtures in a low-power (< or = 10 milliW per cm2) RF discharge at ~ 0.2 Torr pressure, and low substrate temperatures < or = 100(degrees)C, over deposition areas ~ 1000 cm2. Barrier properties of the resulting PV cells and coated-glass packaging structures were studied with subsequent stressing in damp-heat exposure at 85(degrees)C/85% RH. Preliminary results on PV cells and coated glass indicate the palpable benefits of the barriers in mitigating moisture intrusion and degradation of the underlying structures using SiOxNy coatings with thicknesses in the range of 100-200 nm.

At the Savannah River Site (SRS) the Defense Waste Processing Facility (DWPF) has been immobilizing SRS's radioactive high-level waste (HLW) sludge into a borosilicate glass for approximately nine years. Currently the DWPF is immobilizing HLW sludge in Macrobatch 4 (MB4). Each macrobatch is nominally five hundred thousand gallons of HLW and produces nominally five hundred stainless steel canisters two feet in diameter ten feet tall filled with the borosilicate glass. This paper presents results of the characterization of a sample of MB4 glass taken directly from the pour stream of the DWPF melter during the filling of the canister S02312. This canister was the 275th canister filled during immobilizing MB4. The purpose of the sample was to confirm that the leachability of the glass in a standard ASTM test was less than the leachability criterion set forth in the Waste Acceptance Product Specifications (WAPS) for vitrified waste forms for permanent disposal in a Federal geologic repository. The sample was sent to the Savannah River National Laboratory (SRNL) for characterization.

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This paper presents a review of racetrack coil magnet designs and technologies for high field magnets that can be used in LHC upgrade. The designs presented here allow both ''Wind & React'' and ''React & Wind'' technologies as they are based on flat racetrack coils with large bend radii. Test results of the BNL 10.3 T ''React & Wind'' common coil magnet are also presented. A possible use of High Temperature Superconductors (HTS) in future high field accelerator magnets is examined.

This paper presents results of a study of the behavior of technetium-99 (Tc-99) during high level waste (HLW) processing operations at Savannah River Site (SRS). Its behavior during HLW processing is important to understand because Tc-99 can fractionate in the waste and appear in both the sludge and the salt tanks at SRS. It can also be soluble in groundwaters and thus is an important radionuclide that may dictate how much waste has to be removed from a tank to prepare it for permanent closure. The HLW processing steps considered in this study are: (1) The initial caustic neutralization of the acidic waste streams generated in the SRS canyons to prepare the waste for storage in the mild steel tanks in the SRS Tank Farm. Waste that is insoluble in caustic precipitates while soluble elements remain in the supernates. At SRS insoluble components are segregated into sludge tanks and soluble components into the salt tanks. (2) The operations in the SRS Tank Farm that wash the sludge in preparation for immobilization for permanent disposal. (3) The sludge immobilization process in the Defense Waste Processing Facility (DWPF) that solidifies the solids into a stable borosilicate glass. The data in this study …

This report describes how to acquire localized Corrosion kinetic maps for a series of NiCrMo alloys.

High current-density Nb{sub 3}Sn strands made by internal-tin routes are not stable against flux jumps at low fields. Since flux jumps release heat, they can initiate quenching if thermal conductivity to the liquid helium is poor. To make matters worse, tin is a potent contaminant of copper, and reaction of strands to maximize performance leads to the loss of thermal conductivity. We discuss how the root of a solution of this problem lies in optimizing two parameters, RRR and J{sub c}, instead of J{sub c} alone. An important workaround for magnet designers is controlling the balance between performance and stability by reducing the temperature or time of the final heat treatment step. This provides ample J{sub c} while also keeping RRR high. Under these conditions, the instability current density threshold J{sub s} is higher than J{sub c}. Additional factors are also available to improve the management of instabilities, including new strand designs with smaller subelements or divided subelements.

Radionuclide and metal contaminants are present in the badose zone and groundwater throughout the U.S. Department of Energy (DOE) legacy sites.

X-ray imaging is a fundamental diagnostic tool for inertial confinement fusion (ICF) research, and provides data on the size and the shape of the core in implosions. We report on the feasibility and performance analysis of an ignition x-ray imager to be used on cryogenic DT implosions at the National Ignition Facility. The system is intended to provide time-integrated, broadband, moderate-energy x-ray core images of imploding ICF capsules. It is optimized with respect to spatial-resolution, signal-to-background and signal-to-noise ratios, taking into account the extreme operating conditions expected at NIF due to high expected neutrons yields, gamma-rays, and x-rays from laser-plasma interactions.

The injection and storage of anthropogenic CO{sub 2} in deep geologic formations is a potentially feasible strategy to reduce CO{sub 2} emissions and atmospheric concentrations. While the purpose of geologic carbon storage is to trap CO{sub 2} underground, CO{sub 2} could migrate away from the storage site into the shallow subsurface and atmosphere if permeable pathways such as well bores or faults are present. Large-magnitude releases of CO{sub 2} have occurred naturally from geologic reservoirs in numerous volcanic, geothermal, and sedimentary basin settings. Carbon dioxide and natural gas have also been released from geologic CO{sub 2} reservoirs and natural gas storage facilities, respectively, due to influences such as well defects and injection/withdrawal processes. These systems serve as natural and industrial analogues for the potential release of CO{sub 2} from geologic storage reservoirs and provide important information about the key features, events, and processes (FEPs) that are associated with releases, as well as the health, safety, and environmental consequences of releases and mitigation efforts that can be applied. We describe a range of natural releases of CO{sub 2} and industrial releases of CO{sub 2} and natural gas in the context of these characteristics. Based on this analysis, several key conclusions can …

Thermochemical processes are being developed to provide global-scale quantities of hydrogen. A variant on sulfur-based thermochemical cycles is the Hybrid Sulfur (HyS) Process which uses a sulfur dioxide depolarized electrolyzer (SDE) to produce the hydrogen. In FY05, testing at the Savannah River National Laboratory (SRNL) explored a low temperature fuel cell design concept for the SDE. The advantages of this design concept include high electrochemical efficiency and small volumetric footprint that is crucial for successful implementation on a commercial scale. A key component of the SDE is the ion conductive membrane through which protons produced at anode migrate to the cathode and react to produce hydrogen. An ideal membrane for the SDE should have both low ionic resistivity and low sulfur dioxide transport. These features allow the electrolyzer to perform at high currents with low potentials, along with preventing contamination of both the hydrogen output and poisoning of the catalysts involved. Another key component is the electrocatalyst material used for the anode and cathode. Good electrocatalysts should be chemically stable and low overpotential for the desired electrochemical reactions. This report summarizes results from activities to evaluate different membrane and electrocatalyst materials for the SDE. Several different types of commercially-available membranes …

The National Ignition Facility (NIF) is a 192 beam Nd-glass laser facility presently under construction at LLNL. When completed, NIF will produce 1.8 MJ, 500 TW of ultraviolet light making it the world's largest and most powerful laser system. NIF will be the world's preeminent facility for performing experiments for Inertial Confinement Fusion (ICF) and High Energy Density Science (HEDS). The Project, begun in 1995, is over 80% complete. The building and the beam path are essentially complete. Nearly all of the functionality of the laser subsystems has been demonstrated. NIF has demonstrated on a single beam basis that it meets its performance goals and shown the laser's precision and flexibility for pulse shaping, pointing, and timing. Beam conditioning techniques, important for target performance, were also demonstrated. The focal spot can be tailored to user specifications using phase plates. Temporal smoothing using smoothing by spectral dispersion (SSD) as well as polarization smoothing was demonstrated. The remaining work is mostly to complete the optics and install them in the beam path and complete the utilities. Presently, eight beams have been activated through the amplifiers and spatial filters to the switchyard wall. Over 150 kJ of 1{omega} light has been produced with …

This report describes the progress made during the Early Career Principal Investigator (ECPI) project on Algorithmic Techniques for Large Data Sets. Research was carried out in the areas of dimension reduction, clustering and finding structure in data, aggregating information from different sources and designing efficient methods for similarity search for high dimensional data. A total of nine different research results were obtained and published in leading conferences and journals.

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This document defines the procedure necessary to qualify the airborne molecular cleanliness (AMC) of vacuum systems (enclosures or large components) that are placed within the National Ignition Facility (NIF) target chamber or are attached to it and communicate with it during vacuum operation. This test is specific to the NIF target chamber because the allowable time dependent rate of rise in the pore filling of a sol-gel coated SAW sensor is based on some nominal change-out time for the disposable debris shields. These debris shields will be sol-gel coated and thus they represent a means of ''pumping'' AMCs from the target chamber. The debris shield pumping rate sets the allowable change in pore filling with time specified in the test procedure. This document describes a two-part procedure that provides both a static measurement of sol-gel pore filling at the end of a 48-hour test period and a dynamic record of pore-filling measured throughout the test period. Successful qualification of a vacuum system requires that both the static and dynamic measurements meet the criteria set forth in Section 7 of this document.

We discuss uncertainties and possible sources of errors associated with the determination of the diffuse Galactic {gamma}-ray emission using the EGRET data. Most of the issues will be relevant also in the GLAST era. The focus here is on issues that impact evaluation of dark matter annihilation signals against the diffuse {gamma}-ray emission of the Milky Way.

The radiolysis of water in contact with spent nuclear fuel (SNF) will produce oxidants and reductants that can affect the dissolution of the fuel in a geologic disposal site. These products are created by initial radiolytic species which are a function of the type of radiation being emitted by the SNF, i.e. alpha, beta and/or gamma, as well as the energy of this radiation, the fuel grain size (and resulting surface-to-volume ratio) and the fuel-to-water ratio. These products interact with the surface of the fuel, creating new species and ultimately affecting the dissolution rate. The objective of the work reported here is to develop a systematic dosimetry model to determine the dose to water from the SNF as a function of these variables. This dose is calculated for different radiation types as a function of decay for the average fuel composition expected at Yucca Mountain. From these dose calculations the production rate of initial radiolytic products can be estimated. This data provides the basis for subsequent determination of the resulting chemical interactions at the fuel/water interface predicted by published theoretical and experimental data.

Efforts during this second year focused on four areas: (1) continued searching and summarizing of published Fischer-Tropsch synthesis (FTS) mechanistic and kinetic studies of FTS reactions on iron catalysts; (2) investigation of CO adsorption/desorption and temperature programmed hydrogenation (TPH) of carbonaceous species after FTS on unsupported iron and alumina-supported iron catalysts; (3) activity tests of alumina-supported iron catalysts in a fixed bed reactor; (4) sequential design of experiments, for the collection of rate data in a Berty CSTR reactor, and nonlinear-regression analysis to obtain kinetic parameters. Literature sources describing mechanistic and kinetic studies of Fischer-Tropsch synthesis on iron catalysts were compiled in a review. Temperature-programmed desorption/reaction methods (the latter using mass-spectrometry detection and also thermogravimetric analyzer (TGA)) were utilized to study CO adsorption/-desorption on supported and unsupported iron catalysts. Molecular and dissociative adsorptions of CO occur on iron catalysts at 25-150 C. The amounts adsorbed and bond strengths of adsorption are influenced by supports and promoters. That CO adsorbs dissociatively on polycrystalline Fe at temperatures well below those of FT reaction indicates that CO dissociation is facile and unlikely to be the rate-limiting step during FTS. Carbonaceous species formed after FT reaction for only 5 minutes at 200 C were …

The goal of the Biomolecular Simulation of Base Excision Repair and Protein Signaling project is to enhance our understanding of the mechanism of human polymerase-, one of the key enzymes in base excision repair (BER) and the cell-signaling enzymes cyclic-AMP-dependent protein kinase. This work used molecular modeling and simulation studies to specifically focus on the • dynamics of DNA and damaged DNA • dynamics and energetics of base flipping in DNA • mechanism and fidelity of nucleotide insertion by BER enzyme human polymerase-β • mechanism and inhibitor design for cyclic-AMP-dependent protein kinase. Molecular dynamics simulations and electronic structure calculations have been performed using the computer resources at the Molecular Science Computing Facility at the Environmental Molecular Sciences Laboratory.

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