The Minimum Degree algorithm, one of the classical algorithms of sparse matrix computations, is widely used to order graphs to reduce the work and storage needed to solve sparse systems of linear equations. There has been extensive research involving practical implementations of this algorithm over the past two decades. However, little has been done to establish theoretical bounds on the computational complexity of these implementations. We study the Minimum Degree algorithm, and prove time complexity bounds for its widely used variants.

The Lawrence Livermore National Laboratory (LLNL) and the Sandia National Laboratory (SNL) are located at the eastern end of the City of Livermore. Recently the research facilities have been placed on heightened security alerts due to the events of September 11. To respond to the security concerns, LLNL and SNL have proposed to place East Avenue between South Vasco Road and Greenville Road under administrative control. This type of control would require security check points at both ends of this segment of East Avenue, including a truck inspection facility west of the Greenville Road intersection. In this configuration, East Avenue would be closed to general public traffic. The purpose of this traffic study is to determine the potential traffic impact of placing East Avenue under administrative control. The primary focus of the traffic study is to evaluate the proposed modifications to the geometry and operation of East Avenue between South Vasco Road and Greenville Road. The study also includes a review of a traffic study prepared for the closure of East Avenue in 1989 to determine if the assumptions and conclusions of that study remain valid.

We demonstrate the application code ''rap'' which is part of the ''Overture'' library. A CAD geometry imported from an IGES file is first cleaned up and simplified to suit the needs of mesh generation. Thereafter, the topology of the model is computed and a water-tight surface triangulation is created on the CAD surface. This triangulation is used to speed up the projection of points onto the CAD surface during the generation of overlapping surface grids. From each surface grid, volume grids are grown into the domain using a hyperbolic marching procedure. The final step is to fill any remaining parts of the interior with background meshes.

We consider beams which are described by a 4D transverse distribution f(x, y, x', y'), where x' {triple_bond} p{sub x}/p{sub z} and z is the axial coordinate. A two-slit scanner is commonly employed to measure, over a sequence of shots, a 2D projection of such a beam's phase space, e.g., f(x, x'). Another scanner might yield f(y, y') or, using crossed slits, f(x, y). A small set of such 2D scans does not uniquely specify f(x, y, x', y'). We have developed ''tomographic'' techniques to synthesize a ''reasonable'' set of particles in a 4D phase space having 2D densities consistent with the experimental data. These techniques are described in a separate document [A. Friedman, et. al., submitted to Phys. Rev. ST-AB, 2002]. Here we briefly summarize one method and describe progress in validating it, using simulations of the High Current Experiment at Lawrence Berkeley National Laboratory.

The preparation and characterization of energetic composite materials containing nanometer-sized constituents is currently a very active and exciting area of research at laboratories around the world. Some of these efforts have produced materials that have shown very unique and important properties relative to traditional energetic materials. We have previously reported on the use of sol-gel chemical methods to prepare energetic nanocomposites. Primarily we reported on the sol-gel method to synthesize nanometer-sized ferric oxide that was combined with aluminum fuel to make pyrotechnic nanocomposites. Since then we have developed a synthetic approach that allows for the preparation of hybrid inorganic/organic energetic nanocomposites. This material has been characterized by thermal methods, energy-filtered transmission electron microscopy (EFTEM), N, adsorption/desorption methods, and Fourier-Transform (FT-IR) spectroscopy, results of which will be discussed. According to these characterization methods the organic polymer phase fills the nanopores of the composite material, providing superb mixing of the component phases in the energetic nanocomposite. The EFTEM results provide a convenient and effective way to evaluate the intimacy of mixing between these component phases. The safe handling and preparation of energetic nanocomposites is of paramount importance to this research and we will report on studies performed to ensure such.

This report presents vadose sediment characterization data that improves understanding of the nature and extent of past releases in the B tank farm. A vertical borehole, located approximately 15 ft (5 m) from the northeast edge of single-shell tank 241-B-110 was drilled to a total depth of 264.4 ft bgs, the groundwater table was encountered at 255.8 ft bgs. During drilling, a total of 3 two-ft long, 4-inch diameter split-spoon core samples were collected between 10 and 254 ft bgs-an average of every 7.5 ft. Grab samples were collected between these core sample intervals to yield near continuous samples to a depth of 78.3 m (257 ft). Geologic logging occurred after each core segment was emptied into an open plastic container, followed by photographing and sub-sampling for physical and chemical characterization. In addition, 54 out of a total of 120 composite grab samples were opened, sub-sampled, logged, and photographed. Immediately following the geologic examination, the core and selected grab samples were sub-sampled for moisture content, gamma-emission radiocounting, tritium and strontium-90 determinations, total carbon and inorganic carbon content, and 8 M nitric acid extracts (which provide a measure of the total leachable sediment content of contaminants) and one-to-one sediment to water …

We have evaluated a collimator-less gamma-ray imaging system, which is based on thin layers of double-sided strip HPGe detectors. The position of individual gamma-ray interactions will be deduced by the strip addresses and the Ge layers which fired. Therefore, high bandwidth pulse processing is not required as in thick Ge detectors. While the drawback of such a device is the increased number of electronics channels to be read out and processed, there are several advantages, which are particularly important for remote applications: the operational voltage can be greatly reduced to fully deplete the detector and no high bandwidth signal processing electronics is required to determine positions. Only a charge sensitive preamplifier, a slow pulse shaping amplifier, and a fast discriminator are required on a per channel basis in order to determine photon energy and interaction position in three dimensions. Therefore, the power consumption and circuit board real estate can be minimized. More importantly, since the high bandwidth signal shapes are not used to determine the depth position, lower energy signals can be processed. The processing of these lower energy signals increases the efficiency for the recovery of small angle scattering. Currently, we are studying systems consisting of up to ten …

Several software packages have been developed for use by NIF large optics vendors during production of NIF optics. These packages allow specific comparison of the interferometer measurements done on optics against the wavefront requirements for those optics, as given on relevant drawings. This document outlines the various packages, and their specific applications, and describes in some detail the calculational algorithms used. It is intended as the primary reference document for the codes (aside from the source codes themselves). In order to ensure good laser beam quality, NIF requires that all large optics be measured with an interferometer to monitor how that optic will affect beam wavefront quality and focusability. Various specifications for transmitted wavefront (TWF) and reflected wavefront (RWF) for the full-aperture parts, and for various sub-apertures, are given on the large optics drawings. For reference, a summary of the various specifications for the NIF large optics is given in Figure 1. Each large optic in production will be measured against some of these specifications. Other specifications will be monitored in a 'process validation' fashion by measuring a representative sample of parts to assure the process is yielding parts which pass specification. This document will focus on the specifications requiring …

This ALARA analysis of Radiological Control Criteria (RCC) considers alternatives to continued storage of certain DOE mixed wastes. It also considers the option of treating hazardous wastes generated by DOE facilities, which have a very low concentration of radionuclide contaminants, as purely hazardous waste. Alternative allowable contaminant levels examined correspond to doses to an individual ranging from 0.01 mrem/yr to 10 to 20 mrem/yr. Generic waste inventory data and radionuclide source terms are used in the assessment. Economic issues, potential health and safety issues, and qualitative factors relating to the use of RCCs are considered.

In radiation shielding applications we need photon and electron data, as well as computer codes that utilize these data, in order to predict results inexpensively and safely. In this paper we will first cover the current status of available photon and electron data that have only recently been adopted for inclusion in ENDF/B-VI, with emphasis on the improved detail that is included in these data bases. Next we will cover the availability of these data bases and computer codes that use them.

The main goals of this project were the search for a predicted nonmetallic high-pressure phase of Li and finding the metallization conditions for LiH. It has been predicted by Neaton & Ashcroft at Cornell [1] that the lithium atoms would pair at pressures around 100 GPa and their valence electrons would become localized in the interstitial regions and therefore non-conducting. LiH, an ionic compound, provides the unique opportunity to understand the effects of coupling two elements with opposite tendencies at extreme conditions and to study fundamental principles such as metallization and pairing. We measured the electrical conductivity of liquid lithium at pressures up to 1.8 Mbar and 4-fold compression, achieved through shock reverberation experiments [2]. We found that the results were consistent with a departure of the electronic properties of lithium from the nearly free electron approximation at high pressures and with ionic pairing correlations in the Mbar regime. Given the expected small effect of the temperature on the conductivity at high densities, the apparent conductivity drop and the behavior of the ionic core at the highest pressures could be interpreted as a decrease of the overall volume available for the electrons. It may be interesting to see if the …

PNNL estimated the FY2002 energy, environmental, and financial benefits (i.e., metrics) of the technologies and practices in the U.S. Department of Energy's (DOE's) Office of Building Technology, State and Community Programs (BTS). BTS uses the estimates of benefits as part of its annual budget request. This report includes an overview of the analytical approaches used to estimate energy savings for the FY2002 appropriated budget for BTS. The report also includes descriptions of key assumptions and the methodology that is used to calculate energy savings estimates for each BTS program.

This paper presents the physics design of the DARHT-II downstream system, which consists of a diagnostic beam stop, a fast, high-precision kicker system and the x-ray converter target assembly. The beamline configuration, the transverse resistive wall instability and the ion hose instability modeling are presented. They also discuss elimination of spot size dilution during kicker switching and implementation of the foil-barrier scheme to minimize the backstreaming ion focusing effects. Finally, they present the target converter's configuration, and the simulated DARHT-II x-ray spot sizes and doses. Some experimental results, which support the physics design, are also presented.

Alloy 22 (UNS N06022) was selected to fabricate the corrosion resistant outer barrier of a two-layer waste package container for nuclear waste at the designated repository site in Yucca Mountain in Nevada (USA). A testing program is underway to characterize and quantify three main modes of corrosion that may occur at the site. Current results show that the containers would perform well under general corrosion, localized corrosion and environmentally assisted cracking (EAC). For example, the general corrosion rate is expected to be below 100 nm/year and the container is predicted to be outside the range of potential for localized corrosion and environmentally assisted cracking.

PNNL estimated the FY2003 energy, environmental, and financial benefits (i.e., metrics) of the technologies and practices in the U.S. Department of Energy's (DOE's) Office of Building Technology, State and Community Programs (BTS). BTS uses the estimates of benefits as part of its annual budget request. This report includes an overview of the analytical approaches used to estimate energy savings for the FY2003 appropriated budget for BTS. The report also includes descriptions of key assumptions and the methodology that is used to calculate energy savings estimates for each BTS program.

High spatial resolution tomography benefits from a high brightness source (photons/(mr{sup 2} x source area)). A synchrotron radiation source provides extremely high continuous brightness with spectral characteristics suited to a wide variety of imaging needs. Therefore, during the initial testing of the new synchrotron radiation computed tomography (SRCT) system at Stanford Synchrotron Radiation Laboratory, it was suggested that we image a ruled target designed for NIF experiments. This is a detailed report of that imaging effort.

In order to further the goal of optimizing Hanford?s HLW borosilicate flowsheet, a glass formulation effort was launched to develop an advanced high-capacity waste form exhibiting acceptable leach and crystal formation characteristics. A simulated C-106/AY-102 waste envelop inclusive of LAW pretreatment products was chosen as the subject of these nonradioactive optimization efforts. To evaluate this optimized borosilicate waste formulation under continuous dynamic vitrification conditions, a research-scale Joule-heated ceramic melter was used to demonstrate the advanced waste form?s flowsheet. The main objectives of this melter test was to evaluate (1) the processing characteristics of the newly formulated C-106/AY-102 surrogate melter-feed stream, (2) the effectiveness of sucrose as a glass-oxidation-state modifier, and (3) the impact of this reductant upon processing rates.

This report summarizes the earthquake activity on Hanford for FY 2002. Hanford Seismic Monitoring provides an uninterrupted collection of high-quality raw and processed seismic data from the Hanford Seismic Network for the U.S. Department of Energy and its contractors. Hanford Seismic Monitoring also locates and identifies sources of seismic activity and monitors changes in the historical pattern of seismic activity at the Hanford Site. The data are compiled, archived, and published for use by the Hanford Site for waste management, Natural Phenomena Hazards assessments, and engineering design and construction. In addition, the seismic monitoring organization works with the Hanford Site Emergency Services Organization to provide assistance in the event of a significant earthquake on the Hanford Site. The Hanford Seismic Network and the Eastern Washington Regional Network consist of 41 individual sensor sites and 15 radio relay sites maintained by the Hanford Seismic Monitoring staff. For the Hanford Seismic Network, there were 1,177 triggers during fiscal year 2002. Of these triggers, 553 were earthquakes. Two earthquakes were located in the Hanford Seismic Network area. Stratigraphically 13 occurred in the Columbia River basalt, 12 were earthquakes in the pre-basalt sediments, and 17 were earthquakes in the crystalline basement. Geographically, 13 earthquakes …

The goal of the Tank Farm Vadose Zone Project is to define risks from past and future single-shell tank farm activities. This report contains all the geologic, geochemical, and selected physical characterization data collected on vadose zone sediment recovered from a borehole installed northeast of tank BX-102 (borehole 299-E33-45). This report also presents data on the sediment lithologies, the vertical extent of contamination, their migration potential, and the source of the contamination in the vadose zone and perched water east of the BX Tank Farm. The near horizontally bedded, northeasterly dipping sediment likely caused horizontal flow of the migrating contaminants. At borehole 299-E33-45, there are several fine-grained lens within the H2 unit that cause horizontally spreading of percolating fluids. The 21-ft thick Plio-pleistocene fine grained silt/clay unit is also an important horizontal flow conduit as evidenced by the perched water between 227-232 ft bgs. Based on comparing the depth of penetration of contaminants and comparing the percentages that are water leachable, uranium migrates slower than technetium-99 and nitrate. The technetium-99 desorption data are consistently near zero, meaning that the technetium-99 is not interacting with the sediment. In summary, the moisture content, pH, electrical conductivity, sodium, tritium, and uranium profiles do …

In developing the Field Investigation Report (FIR) for the Waste Management Area (WMA) S-SX at the Hanford Site, cesium-137 was the only gamma emitting radionuclide of concern (Knepp 2002). However, in WMA B-BX-BY, the spectral gamma logging data identify seven gamma emitting radionuclides, cesium-137, antimony-125, europium-152 and -154, cobalt-60, uranium-235 and -238 (DOE-GJPO 1998). The geochemical behaviors of several of these radionuclides, antimony-125 and the two europium isotopes, have not been extensively investigated at the Hanford Site. This task was initiated to assure that our understanding of the geochemical properties affecting the environmental behavior of these radionuclides reflects the current state of knowledge. A literature review was conducted to assess the important oxidation/reduction, aqueous speciation, solubility, and adsorption processes affecting the environmental behavior of antimony, cobalt, europium, technetium, and uranium in vadose zone sediments with low-organic matter content in semi-arid environments such as those at the Hanford Site. Technetium-99 was included in this task because of its importance in the long-term risk calculations. This report presents the results of this literature review.

The aim of these studies continues to be the investigation into the molecular mechanisms that underlie the virulence process in Yersinia pestis. In particular, the focus of this work centers on the identification of novel genes and pathways responsible for the pathogenic properties of this organism. In spite of more than four decades of intense investigation in this field, the dilemma as to what makes Y. pestis such a virulent and lethal pathogen remains unanswered. The method being employed makes use microarray technology (DNA chip) that enables the examination of the global activities of the whole complement of genes in this pathogen. Two primary resources available to the investigators (one directly obtained from a separate CBNP-funded project) make these studies possible: (1) Whole genome comparisons of the genes in Y. pestis and its near neighbors with attenuated or non pathogenic characteristics, and (2) the ability to duplicate in vitro, conditions that mimic the infection process of this pathogen. This year we have extended our studies from the original work of characterizing the global transcriptional regulation in Y. pestis triggered during temperature transition from 26 C to 37 C (roughly conditions found in the flea vector and the mammalian host, respectively) …

Low-defect multilayer coatings are required to fabricate mask blanks for Extreme Ultraviolet Lithography (EUVL). The mask blanks consist of high reflectance E W multilayers on low thermal expansion substrates. A defect density of 0.0025 printable defects/cm{sup 2} for both the mask substrate and the multilayer is required to provide a mask blank yield of 60%. Current low defect multilayer coating technology allows repeated coating-added defect levels of 0.05/cm{sup 2} for defects greater than 90 nm polystyrene latex sphere (PSL) equivalent size for lots of 20 substrates. Extended clean operation of the coating system at levels below 0.08/cm{sup 2} for 3 months of operation has also been achieved. Two substrates with zero added defects in the quality area have been fabricated, providing an existence proof that ultra low defect coatings are possible. Increasing the ion source-to-target distance from 410 to 560 mm to reduce undesired coating of the ion source caused the defect density to increase to 0.2/cm{sup 2}. Deposition and etching diagnostic witness substrates and deposition pinhole cameras showed a much higher level of ion beam spillover (ions missing the sputter target) than expected. Future work will quantify beam spillover, and test designs to reduce spillover, if it is confirmed …

The objective of this study was to compare the mixing performance of the Lawrence pump, which has injection nozzles at the top, with an alternative pump that has injection nozzles at the bottom, and to determine the optimal elevation for the alternative pump. Sixteen cases were evaluated: two sludge thicknesses at eight levels. A two-step evaluation approach was used: Step 1 to evaluate all 16 cases with the non-rotating mixer pump model and Step 2 to further evaluate four of those cases with the more realistic rotating mixer pump model. The TEMPEST code was used.

The motivation for the ''Transparency'' experiment is that DOE/DP would like to have data available to show to interested parties, such as the JASONs. The U1a subcritical experiments are consistent with U.S. policy on nuclear testing. This would be done in a spirit of ''Transparency'' if doubts should arise. Thus, the objective of the ''Transparency'' measurements on the Oboe series is to place an upper bound on the nuclear energy released in the subcritical experiments. Two separate experimental packages cover the transparency measurement issue thoroughly. These are: (1) Neutron Track-Etch Dosimetry. (2) Scintillator Fission Neutron/Gamma Rate Measurement. Because the containment barrier is only 1-inch steel, plus 6-inch shotcrete, it is quite transparent to fission neutrons and, thus, both experiments can be mounted outside the containment barrier and can be recovered post shot. An additional group of dosimeters was placed on the lid of the vessel for greater sensitivity.