We report a two-step growth method to obtain uniformly coalesced epitaxial lateral overgrown a-plane GaN by metal-organic chemical vapor deposition (MOCVD). By obtaining a large wing height to width aspect ratio in the first step followed by enhanced lateral growth in the second step via controlling the growth temperature, we reduced the tilt angle between the advancing Ga-polar and N-polar wings for improved properties. Transmission electron microscopy (TEM) showed that the threading dislocation density in the wing area was 1.0 x 10{sup 8}cm{sup -2}, more than two orders of magnitude lower than that in the window area (4.2 x 10{sup 10} cm{sup -2}). However, a high density of basal stacking faults, 1.2 x 10{sup 4} cm{sup -1}, was still observed in the wing area. Near field scanning optical microscopy (NSOM) at room temperature revealed that the luminescence was mainly from the wing regions with very little contribution from the windows and meeting fronts. These observations suggest that due to significant reduction of threading dislocations radiative recombination is enhanced in the wings.

The purpose of this calculation is to evaluate the thermal performance of the Naval Long and Naval Short spent nuclear fuel (SNF) waste packages (WP) in the repository emplacement drift. The scope of this calculation is limited to the determination of the temperature profiles upon the surfaces of the Naval Long and Short SNF waste package for up to 10,000 years of emplacement. The temperatures on the top of the outside surface of the naval canister are the thermal interfaces for the Naval Nuclear Propulsion Program (NNPP). The results of this calculation are intended to support Licensing Application design activities.

Results from a confirmatory survey of the upper structural surfaces of the Reactor Building Dome at the Rancho Seco Nuclear Generating Station (RSNGS) performed by the Oak Ridge Institute for Science and Education for the NRC. Also includes results of interlaboratory comparison analyses on several archived soil samples that would be provided by RSNGS personnel. The confirmatory surveys were performed on June 7 and 8, 2006.

Triple junctions are often initiation points for insulator flashover in pulsed power devices. The two-dimensional finite-element TriComp [1] modeling software suite was utilized for its electrostatic field modeling package to investigate electric field behavior in the anode and cathode triple junctions of a high voltage vacuum-insulator interface. TriComp enables simple extraction of values from a macroscopic solution for use as boundary conditions in a subset solution. Electric fields computed with this zoom capability correlate with theoretical analysis of the anode and cathode triple junctions within submicron distances for nominal electrode spacing of 1.0 cm. This paper will discuss the iterative zoom process with TriComp finite-element software and the corresponding theoretical verification of the results.

Recent microfabrication technologies based on LIGA (German acronym for Lithographe, Galvanoformung, und Abformung) have been applied to build high-aspect-ratio, metallic or dielectric, planar structures suitable for high-frequency rf cavity structures. The cavity structures would be used as parts of linear accelerators, microwave undulators, and mm-wave amplifiers. The microfabrication process includes manufacturing of precision x-ray masks, exposure of positive resist by x-rays through the mask, resist development, and electroforming of the final microstructure. Prototypes of a 32-cell, 108-GHz constant impedance cavity and a 66-cell, 94-GHz constant-gradient cavity were fabricated using the synchrotron radiation sources at APS. Preliminary design parameters for a 91-GHz modulator klystron along with an overview of the new technology are discussed.

This report details the work done between June 13 andSeptember 30, 2006 by Lawrence Berkeley National Laboratory (LBNL)scientists to assist Fermi National Accelerator Laboratory (Fermilab)staff in understanding tritium transport at the Neutrino at the MainInjector (NuMI) facility. As a byproduct of beamline operation, thefacility produces (among other components) tritium in engineeredmaterials and the surrounding rock formation. Once the tritium isgenerated, it may be contained at the source location, migrate to otherregions within the facility, or be released to theenvironment.

Analysis of poly(ethylene glycol)(PEG)-containing particles by online single particle aerosol mass spectrometers equipped with laser desorption ionization (LDI) is reported. We demonstrate that PEG-containing particles are useful in the development of aerosol mass spectrometers because of their ease of preparation, low cost, and inherently recognizable mass spectra. Solutions containing millimolar quantities of PEGs were nebulized and, after drying, the resultant micrometer-sized PEG containing particles were sampled. LDI (266 nm) of particles containing NaCl and PEG molecules of average molecular weight <500 generated mass spectra reminiscent of mass spectra of PEG collected by other MS schemes including the characteristic distribution of positive ions (Na{sup +} adducts) separated by the 44 Da of the ethylene oxide units separating each degree of polymerization. PEGs of average molecular weight >500 were detected from particles that also contained t the tripeptide tyrosine-tyrosine-tyrosine or 2,5-dihydroxybenzoic acid, which were added to nebulized solutions to act as matrices to assist LDI using pulsed 266 nm and 355 nm lasers, respectively. Experiments were performed on two aerosol mass spectrometers, one reflectron and one linear, that each utilize two time-of-flight mass analyzers to detect positive and negative ions created from a single particle. PEG-containing particles are currently being employed in …

There are several lines of evidence which suggest that the relativistic outflows in gamma-ray bursts (GRBs) are collimated into narrow jets. The jet structure has important implications for the true energy release and the event rate of GRBs, and can constrain the mechanism responsible for the acceleration and collimation of the jet. Nevertheless, the jet structure and its dynamics as it sweeps up the external medium and decelerates, are not well understood. In this review I discuss our current understanding of GRB jets, stressing their structure and dynamics.

The purpose of this calculation is to tabulate a set of computer files for use as input to the WPLOAD thermal loading software. These files contain details regarding heat and radiation from pressurized water reactor (PWR) assemblies and boiling water reactor (BWR) assemblies. The scope of this calculation is limited to rearranging and reducing the existing file information into a more streamlined set of tables for use as input to WPLOAD. The electronic source term files used as input to this calculation were generated from the output files of the SAS2H/ORIGIN-S sequence of the SCALE Version 4.3 modular code system, as documented in References 2.1.1 and 2.1.2, and are included in Attachment II.

This report documents the deactivation, decontamination, decommissioning, and demolition of five buildings in the 300 Area of the Hanford Site. The D4 of these facilities included characterization, engineering, removal of hazardous and radiologically contaminated materials, equipment removal, utility disconnection, deactivation, decontamination, demolition of the structure, and stabilization or removal of the remaining slab and foundation as appropriate.

The Pacific Northwest National Laboratory (PNNL) is assembling existing borehole geologic information to aid in determining the distribution and potential movement of contaminants released to the environment and to aid selection of remedial alternatives. This information is being assembled via the Hanford Borehole Geologic Information System (HBGIS), which is being developed as part of the Characterization of Systems Project, managed by PNNL, and the Remediation Decision Support Task of the Groundwater Remediation Project, managed by Fluor Hanford, Inc. The purpose of this particular study was to assemble the existing borehole geologic data pertaining to sediments underlying the 216-Z Crib Facilities and the Plutonium Finishing Plant Closure Zone. The primary objective for Fiscal Year 2006 was to assemble the data, complete log plots, and interpret the location of major geologic contacts for each major borehole in and around the primary disposal facilities that received carbon tetrachloride. To date, 154 boreholes located within or immediately adjacent to 19 of the 216-Z crib facilities have been incorporated into HBGIS. Borehole geologic information for the remaining three Z-crib facilities is either lacking (e.g. 216-Z-13, -14, and -15), or has been identified as a lesser priority to be incorporated at a later date.

Critical gaps exist in our capabilities to rapidly characterize threat agents which could be used in attacks on facilities and military forces. DNA-based PCR and immunoassay-based techniques provide unique identification of species, strains and protein signatures of pathogens. However, differentiation between naturally occurring and weaponized bioagents and the identification of formulation signatures are beyond current technologies. One of the most effective and often the only definitive means to identify a threat agent is by its direct visualization. Atomic force microscopy (AFM) is a rapid imaging technique that covers the size range of most biothreat agents (several nanometers to tens of microns), is capable of resolving pathogen morphology and structure, and could be developed into a portable device for biological weapons (BW) field characterization. AFM can detect pathogens in aerosol, liquid, surface and soil samples while concomitantly acquiring their weaponization and threat agent digital signatures. BW morphological and structural signatures, including modifications to pathogen microstructural architecture and topology that occur during formulation and weaponization, provide the means for their differentiation from crude or purified unformulated agent, processing signatures, as well as assessment of their potential for dispersion, inhalation and environmental persistence. AFM visualization of pathogen morphology and architecture often provides valuable …

A total of six core samples from 200-UP/ZP-1 OUs and two additional outcrop samples were characterized during FY2006 by PNNL. One sample (C4971) was identified as slough and not used, but the five other samples identified as intact core samples were used for further analyses. The C4977 sample is gravel-sandy silt and C4990 samples are fine-sandy silt from the Ringold formation. Although the sediments from these two boreholes have similar mineralogical composition, C4990 samples show higher values of Fe oxide content, clay/silt content, and surface area compared those in C4977. The measured Tc Kd values ranged 0–0.2 mg/L for both samples, while U(VI) Kd for C4990 (4.23 mg/L) is much higher than that for C4977 (0.76 mg/L). A key finding from the Kd measurements is that detailed sediment and pore water characterization is necessary to understand the variation in Kd values seen in the empirical batch tests. Without the ancillary characterization of the sediments and pore waters, one might form misleading interpretations of the mechanisms that control the Kd values. Thus, physical, geochemical, and hydrological characterization of the sediments and pore waters should be conducted to increase our understanding of the site-specific Kd measurements. More details for methods and results …

This report presents the results of a delineation of waters of the United States, including wetlands, for Lawrence Livermore National Laboratory's Site 300 in Alameda and San Joaquin Counties, California. Jones & Stokes mapped vegetation at Site 300 in August, 2001, using Global Positioning System (GPS) data recorders to collect point locations and to record linear features and map unit polygons. We identified wetlands boundaries in the field on the basis of the plant community present. We returned to collect additional information on wetland soils on July 3, 2002. Forty-six wetlands were identified, with a total area of 3.482 hectares (8.605 acres). The wetlands include vernal pools, freshwater seeps, and seasonal ponds. Wetlands appearing to meet the criteria for federal jurisdictional total 1.776 hectares (4.388 acres). A delineation map is presented and a table is provided with information on the type, size, characteristic plant species of each wetland, and a preliminary jurisdictional assessment.

The underlying goal of this project was to provide multi-disciplinary engineering training for graduate students in the area of internal combustion engines, specifically in direct injection compression ignition engines. The program was designed to educate highly qualified engineers and scientists that will seek to overcome technological barriers preventing the development and production of cost-effective high-efficiency vehicles for the US. market. Further, these highly qualified engineers and scientists will foster an educational process to train a future workforce of automotive engineering professionals who are knowledgeable about and have experience in developing and commercializing critical advanced automotive technologies. Eight objectives were defined to accomplish this goal: (1) Develop an interdisciplinary internal combustion engine curriculum emphasizing direct injected combustion ignited diesel engines. (2) Encourage and promote interdisciplinary interaction of the faculty. (3) Offer a Ph.D. degree in internal combustion engines based upon an interdisciplinary curriculum. (4) Promote strong interaction with industry, develop a sense of responsibility with industry and pursue a self sustaining program. (5) Establish collaborative arrangements and network universities active in internal combustion engine study. (6) Further Enhance a First Class educational facility. (7) Establish ''off-campus'' M.S. and Ph.D. engine programs of study at various industrial sites. (8) Extend and Enhance …

X-ray absorption methods have been successfully used to obtain quantitative information about local atomic composition of two different materials. X-ray Absorption Near Edge Structure analysis and X-Ray Photoelectron Spectroscopy allowed us to determine seven chemical compounds and their concentrations in c-BN composite. Use of Extended X-ray Absorption Fine Structure in combination with Transmission Electron Microscopy enabled us to determine the composition and size of buried Ge quantum dots. It was found that the quantum dots consisted out of pure Ge core covered by 1-2 monolayers of a layer rich in Si.

This document is intended to facilitate calculation of inelastic scattering and charge-exchange cross sections in a variety of reaction models, including the plane-wave and distorted-wave approximations and the full coupled-channels treatments. Expressions are given for the coupling potentials between the relevant channels in both coordinate and momentum space. In particular, it is expected that the plane-wave calculations should be useful as a check on the correctness of coupled-channels calculations. The Fourier transform methods used to calculate the plane-wave approximation cross sections are also intended to be used to generate the transition potentials for coupled-channels codes, using a folding model with local effective interactions. Specific expressions are given for calculating transition densities for the folding model in the random phase approximation (RPA).

Multigrid methods are ideal for solving the increasingly large-scale problems that arise in numerical simulations of physical phenomena because of their potential for computational costs and memory requirements that scale linearly with the degrees of freedom. Unfortunately, they have been historically limited by their applicability to elliptic-type problems and the need for special handling in their implementation. In this paper, we present an overview of several recent theoretical and algorithmic advances made by the TOPS multigrid partners and their collaborators in extending applicability of multigrid methods. Specific examples that are presented include quantum chromodynamics, radiation transport, and electromagnetics.

Five projects are proposed, in an effort to supplement the efforts of fuel cell research at the University of South Carolina and to contribute to the Technical Plan for Fuel Cells of the Department of Energy. These efforts include significant interaction with the industrial community through DOE funded projects and through the National Science Foundation’s Industry/University Cooperative Research Center for Fuel Cells. The allocation of projects described below leverage all of these sources of funding without overlap and redundancy. The first project “Novel Non-Precious Metal Catalyst For PEMFCs,” (Dr. Branko Popov) continues DOE award DE-FC36-03GO13108 for which funding was delayed by DOE due to budget constraints. The purpose of this project is to develop an understanding of the feasibility and limitations of metal-free catalysts. The second project, “Non Carbon Supported Catalysts” (Dr. John Weidner), is focused on improved catalysts and seeks to develop novel materials, which are more corrosion resistant. This corrosion behavior is critical during transient operation and during start-up and shutdown. This second project will be leveraged with recent, peer-reviewed, supplemental funding from NSF for use in the National Science Foundation Industry/University Cooperative Research Center for Fuel Cells (CFC) at USC. The third project, “Hydrogen Quality,” (Dr. Jean …

Five projects were conducted in an effort to supplement the efforts of fuel cell research at the University of South Carolina and to contribute to the Technical Plan for Fuel Cells of the Department of Energy. These efforts include significant interaction with the industrial community through DOE funded projects and through the National Science Foundation�s Industry/University Cooperative Research Center (NSF-I/UCRC) for Fuel Cells at USC. The allocation of projects described below leveraged all of these sources of funding without overlap and redundancy. 1. "Novel Non-Precious Metal Catalyst For PEMFCs" (Dr. Branko Popov) 2. "Non Carbon Supported Catalysts" (Dr. John Weidner) 3. "Hydrogen Quality" (Dr. Jean St-Pierre) 4. "Gasket Materials: Mechanical and Chemical Stability in PEMFC" (Dr. Y.J. (Bill) Chao) 5. "Mathematical Modeling of PEM Fuel Cells," (Dr. Sirivatch (Vatch) Shimpalee)

Yucca Mountain has been proposed as the site for the Nation's first geologic repository for high-level radioactive waste. This chapter provides the geologic framework for the Yucca Mountain region. The regional geologic units range in age from late Precambrian through Holocene, and these are described briefly. Yucca Mountain is composed dominantly of pyroclastic units that range in age from 11.4 to 15.2 Ma. The proposed repository would be constructed within the Topopah Spring Tuff, which is the lower of two major zoned and welded ash-flow tuffs within the Paintbrush Group. The two welded tuffs are separated by the partly to nonwelded Pah Canyon Tuff and Yucca Mountain Tuff, which together figure prominently in the hydrology of the unsaturated zone. The Quaternary deposits are primarily alluvial sediments with minor basaltic cinder cones and flows. Both have been studied extensively because of their importance in predicting the long-term performance of the proposed repository. Basaltic volcanism began about 10 Ma and continued as recently as about 80 ka with the eruption of cones and flows at Lathrop Wells, approximately 10 km south-southwest of Yucca Mountain. Geologic structure in the Yucca Mountain region is complex. During the latest Paleozoic and Mesozoic, strong compressional forces …

Yucca Mountain in southwestern Nevada is a prominent, irregularly shaped upland formed by a thick apron of Miocene pyroclastic-flow and fallout tephra deposits, with minor lava flows, that was segmented by through-going, large-displacement normal faults into a series of north-trending, eastwardly tilted structural blocks. The principal volcanic-rock units are the Tiva Canyon and Topopah Spring Tuffs of the Paintbrush Group, which consist of volumetrically large eruptive sequences derived from compositionally distinct magma bodies in the nearby southwestern Nevada volcanic field, and are classic examples of a magmatic zonation characterized by an upper crystal-rich (> 10% crystal fragments) member, a more voluminous lower crystal-poor (< 5% crystal fragments) member, and an intervening thin transition zone. Rocks within the crystal-poor member of the Topopah Spring Tuff, lying some 280 m below the crest of Yucca Mountain, constitute the proposed host rock to be excavated for the storage of high-level radioactive wastes. Separation of the tuffaceous rock formations into subunits that allow for detailed mapping and structural interpretations is based on macroscopic features, most importantly the relative abundance of lithophysae and the degree of welding. The latter feature, varying from nonwelded through partly and moderately welded to densely welded, exerts a strong control …

The objective of this document is to support the simulation results reported by Corbin et al. (2005) by documenting the requirements, conceptual model, simulation methodology, testing, and quality assurance associated with the Hanford Soil Inventory Model (SIM). There is no conventional software life-cycle documentation associated with the Hanford SIM because of the research and development nature of the project. Because of the extensive use of commercial- off-the-shelf software products, there was little actual software development as part of this application. This document is meant to provide historical context and technical support of Corbin et al. (2005), which is a significant revision and update to an earlier product Simpson et al. (2001). The SIM application computed waste discharges composed of 75 analytes at 377 waste sites (liquid disposal, unplanned releases, and tank farm leaks) over an operational period of approximately 50 years. The development and application of SIM was an effort to develop a probabilistic approach to estimate comprehensive, mass balanced-based contaminant inventories for the Hanford Site post-closure setting. A computer model capable of calculating inventories and the associated uncertainties as a function of time was identified to address the needs of the Remediation and Closure Science (RCS) Project.

The focus of the development and application of a soil inventory model as part of the Remediation and Closure Science (RCS) Project managed by PNNL was to develop a probabilistic approach to estimate comprehensive, mass balanced-based contaminant inventories for the Hanford Site post-closure setting. The outcome of this effort was the Hanford Soil Inventory Model (SIM). This document is a user's guide for the Hanford SIM. The principal project requirement for the SIM was to provide comprehensive quantitative estimates of contaminant inventory and its uncertainty for the various liquid waste sites, unplanned releases, and past tank farm leaks as a function of time and location at Hanford. The majority, but not all of these waste sites are in the 200 Areas of Hanford where chemical processing of spent fuel occurred. A computer model capable of performing these calculations and providing satisfactory quantitative output representing a robust description of contaminant inventory and uncertainty for use in other subsequent models was determined to be satisfactory to address the needs of the RCS Project. The ability to use familiar, commercially available software on high-performance personal computers for data input, modeling, and analysis, rather than custom software on a workstation or mainframe computer for …