We have measured the polarization of the heliumlike sulfur resonance line 1s2p {sup 1}P{sub 1} {yields} 1s{sup 2} {sup 1}S{sub 0}, and of the blend of the lithiumlike sulfur resonance lines 1s2s2p {sup 2}P{sub 3/2} {yields} 1s{sup 2}2s {sup 2}S{sub 1/2} and 1s2s2p {sup 2}P{sub 1/2} {yields} 1s{sup 2}2s {sup 2}S{sub 1/2} as a function of electron beam energy from near threshold to 144 keV. These lines were excited with the LLNL high-energy electron beam ion trap and measured using a newly modified two-crystal technique. Our results test polarization predictions in an energy regime where few empirical results have been reported. We also present calculations of the polarization using two different methods, and good agreement is obtained.

Surfaces of steel structures that enclose high-fluence, large-beam lasers have conventional and unconventional requirements. Aside from rust prevention, the surfaces must resist laser-induced degradation and the contamination of the optical components. The latter requires a surface that can be precision cleaned to low levels of particulate and organic residue. In addition, the surface treatment for the walls should be economical to apply because of the large surface areas involved, and accommodating with intricate joint geometries. Thermal sprayed coatings of aluminum (Al) and stainless steel are candidate surface materials. Coatings are produced and characterized for porosity, smoothness, and hardness. These properties have a bearing on the cleanliness of the coating. The laser resistance of Al and 3 16L coatings are given. The paper summarizes the characterization of twin-wire-arc deposited Al, high-velocity-oxygen-fueled (HVOF) deposited Al, flame-sprayed 316L, and HVOF deposited316L. The most promising candidate coating is that of HVOF Al. This Al coating has the lowest porosity (8%) compared the other three coatings and relatively low hardness (100 VHN). The as-deposited roughness (Ra) is 433 pinches, but after a quick sanding by hand, the roughness decreased to 166 pinches. Other post-coat treatments are discussed. HVOF aluminum coatings are demonstrated. Al coatings are …

Chromosome 19 has the highest gene density of all human chromosomes, more than double the genome-wide average. The large clustered gene families, corresponding high GC content, CpG islands and density of repetitive DNA indicate a chromosome rich in biological and evolutionary significance. Here we describe 55.8 million base pairs of highly accurate finished sequence representing 99.9% of the euchromatin portion of the chromosome. Manual curation of gene loci reveals 1,461 protein-coding genes and 321 pseudogenes. Among these are genes directly implicated in Mendelian disorders, including familial hypercholesterolemia and insulin-resistant diabetes. Nearly one quarter of these genes belong to tandemly arranged families, encompassing more than 25% of the chromosome. Comparative analyses show a fascinating picture of conservation and divergence, revealing large blocks of gene orthology with rodents, scattered regions with more recent gene family expansions and deletions, and segments of coding and non-coding conservation with the distant fish species Takifugu.

A membrane of multiwalled carbon nanotubes embedded in a silicon nitride matrix was fabricated for use in studying fluid mechanics on the nanometer scale. Characterization by fluorescent tracer diffusion and scanning electron microscopy suggests that the membrane is void-free near the silicon substrate on which it rests, implying that the hollow core of the nanotube is the only conduction path for molecular transport. Assuming Knudsen diffusion through this nanotube membrane, a maximum helium transport rate (for a pressure drop of 1 atm) of 0.25 cc/sec is predicted. Helium flow measurements of a nanoporous silicon nitride membrane, fabricated by sacrificial removal of carbon, give a flow rate greater than 1x10{sup -6} cc/sec. For viscous, laminar flow conditions, water is estimated to flow across the nanotube membrane (under a 1 atm pressure drop) at up to 2.8x10{sup -5} cc/sec (1.7 {micro}L/min).

An indirect method for determining cross sections for reactions proceeding through a compound nucleus is presented. Exploring indirect approaches for obtaining reaction cross sections is important since a large number of reactions relevant to astrophysics cannot be measured with currently available techniques. Of particular importance are reactions involving unstable nuclei. Some applications of the Surrogate nuclear reactions method are considered and challenges that need to be addressed are outlined.

The response of the land biosphere to the ongoing increase in atmospheric CO{sub 2} is not fully understood. To evaluate the approximate upper and lower limits of land sequestration of carbon, we performed simulations using a comprehensive carbon-climate model. In one case the land biosphere is vigorously fertilized by added CO{sub 2} and sequesters carbon throughout the 21st century. In a second case, CO{sub 2} fertilization saturates in year 2000; in this case the land becomes an additional source of CO{sub 2} by 2050. The predicted atmospheric CO{sub 2} concentration at year 2100 differs by 40% between the two cases. Current uncertainties preclude determination of whether the land biosphere will amplify or damp atmospheric CO{sub 2} increases by the end of the century.

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A variational analysis is used to derive a mixed P{sub 1}DP{sub 0} (spherical harmonics-double spherical harmonics) angular approximation to the time-independent monoenergetic neutron transport equation with linearly anisotropic scattering in one-dimensional planar geometry. This mixed approximation contains a space-dependent weight factor {alpha}(x) that controls the local angular approximation used: {alpha}(x) = 1 yields the standard P{sub 1} (diffusion) approximation, {alpha}(x) = 0 gives the standard DP{sub 0} approximation, and 0 < {alpha}(x) < 1 produces a mixed approximation. The diffusion equation obtained differs from the standard P{sub 1} diffusion equation only in the definition of the diffusion coefficient. The variational analysis shows that both the scalar flux and the current are continuous at material interfaces regardless of the value of {alpha}(x). Standard Marshak boundary conditions are also obtained via the variational analysis. In this paper, they examine the use of this mixed angular approximation to more accurately treat material interfaces and vacuum boundaries. Numerical results from a mixed-oxide fuel test problem are presented to demonstrate that significant improvements in accuracy can be obtained using this method. For this test problem, the mixed P{sub 1}-DP{sub 0} angular approximation with {alpha} = 0.25 is found to be more robust than the standard …

The objective of this work is to determine the chemical composition of nanometer precipitates responsible for irradiation hardening and embrittlement of reactor pressure vessel steels, which threaten to limit the operating lifetime of nuclear power plants worldwide. The scientific approach incorporates computational multiscale modeling of radiation damage and microstructural evolution in Fe-Cu-Ni-Mn alloys, and experimental characterization by positron annihilation spectroscopy and small angle neutron scattering. The modeling and experimental results are

UDP-Glucuronosyltransferase 1A proteins (UGT1A) catalyze the glucuronidation of many endogenous and xenobiotic compounds including heterocyclic amines and their hydroxylated metabolites (the main topic of this study). Studies have shown that in humans UGT1A mediated glucuronidation is an important pathway in the detoxification of food-borne carcinogenic heterocyclic amines. The biotransformation of 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), the most mass abundant heterocyclic amine found in cooked meats, is highly dependent on cytochrome P4501A2 hydroxylation followed by UGT catalyzed glucuronidation of the N-hydroxy-PhIP reactive intermediate. To determine which UGT1A proteins are involved in the glucuronidation of N-hydroxy-PhIP, microsomal preparations from baculovirus infected insect cells that express all of the known functional human UGT1A isozymes (UGT1A1, -1A3, -1A4, -1A6, -1A7, -1A8, -1A9, -1A10) were exposed to N-hydroxy-PhIP and the reaction products were isolated by HPLC. All UGT1A proteins except UGT1A6 showed some degree of activity towards N-hydroxy-PhIP. The formation of both N-hydroxy-PhIP-N{sup 2}-glucuronide and N-hydroxy-PhIP-N3-glucuronide was both time and substrate concentration dependent in all the microsomal incubations that showed appreciable activity. UGT1A1 was the most efficient in converting N-hydroxy-PhIP to both conjugates producing 5 times more of the N{sup 2}-conjugate than UGT1A4, the next active UGT, and 286 times more than UGT1A7, the least active UGT. With …

A unique gold nanoparticle aggregate (GNA) system has been shown to be an excellent substrate for surface-enhanced Raman scattering (SERS) applications. Rhodamine 6G (R6G), a common molecule used for testing SERS activity on silver, but generally difficult to detect on gold substrates, has been found to readily bind to the GNA and exhibit strong SERS activity due to the unique surface chemistry afforded by sulfur species on the surface. This GNA system has yielded a large SERS enhancement of 10{sup 7}-10{sup 9} in bulk solution for R6G, on par with or greater than any previously reported gold SERS substrate. SERS activity has also been successfully demonstrated for several biological molecules including adenine, L-cysteine, L-lysine, and L-histidine for the first time on a gold SERS substrate, showing the potential of this GNA as a convenient and powerful SERS substrate for biomolecular detection. In addition, SERS spectrum of R6G on single aggregates has been measured. We have shown that the special surface properties of the GNA, in conjunction with strong near IR absorption, make it useful for SERS analysis of a wide variety of molecules.

We examine how quantitative rock physics models, such as effective medium theories, can improve the interpretation of seismic parameters and material and fluid properties at The Geysers. We use effective medium theories to estimate effects of fractures on velocities for The Geysers rocks. We compare theoretical velocity estimates to laboratory measurements from the literature and our seismic velocity values from 1992 earthquake data. We approximate the reservoir as being homogeneous in mineral composition, with a constant density of fractures whose total void ratio is reduced by lithostatic pressure. Thus, we expect low velocities near the surface, increasing with depth up to the values observed in the lab on intact samples, 5.5 - 5.7 km/sec. We use a one-dimensional inversion of P-waves to obtain an ''expected'' P-wave velocity (Vp) and attenuation (Qp) relation as a function of depth for The Geysers rocks. We then use a three-dimensional Vp and Qp inversion to find anomalous zones within the reservoir. We find portions with ''high'' Vp and Qp, high Vp and low Qp, and low Vp and low Qp. We interpret the regions with high Vp and Qp to be relatively less fractured, and the regions with low Vp and Qp to be …

It is not widely acknowledged or appreciated that conventional, two-stage light-gas launchers do not efficiently apply their high breech pressures to the design intent: accelerating the projectile. Our objective in this project was to carry out the analysis, design, construction, and testing of a new class of launchers that will address this limitation. Our particular application is to expand the pressure range of the conventional, two-stage gas launcher to overlap and validate the pressure regimes previously attainable only with shock waves generated by nuclear explosions, lasers, or multistage conventional explosions. That is, these launchers would have the capability to conduct--in a laboratory setting--high-velocity-impact, equation-of-state (EOS) measurements at up to 2-TPa (20 Mbar) pressure levels in high-Z materials. Our design entailed a new class of distributed-injection, gas-dynamic launchers that are designed to use a boat-tail projectile to overcome the fundamental gas-expansion phenomena known as escape velocity (the Riemann limit). Our program included analytical, numerical, and experimental studies of the fast gas release flow technique that is central to the success of our approach. The analyses led us to believe that, in a typical configuration, the pressure will be effectively applied to the projectile in a time short relative to its few-microsecond …

Cross section measurements were made of prompt {gamma}-ray production as a function of incident neutron energy on a {sup 48}Ti sample. Partial {gamma}-ray cross sections for transitions in {sup 45-48}Ti, {sup 44-48}Sc, and {sup 42-45}Ca have been determined. Energetic neutrons were delivered by the Los Alamos National Laboratory spallation neutron source located at the LANSCE/WNR facility. The prompt-reaction {gamma} rays were detected with the large-scale Compton-suppressed germanium array for neutron induced excitations (GEANIE). Neutron energies were determined by the time-of-flight technique. The {gamma}-ray excitation functions were converted to partial {gamma}-ray cross sections taking into account the dead-time correction, target thickness, detector efficiency and neutron flux (monitored with an in-line fission chamber). The data are presented for neutron energies E{sub n} between 1 to 200 MeV. These results are compared with model calculations which include compound nuclear and pre-equilibrium emission. The model calculations are performed using the STAPRE reaction code for E{sub n} up to 20 MeV and the GNASH reaction code for E{sub n} up to 120 MeV. Using the GNASH reaction code the effect of the spin distribution in preequilibrium reactions has been investigated. The preequilibrium reaction spin distribution was calculated using the quantum mechanical theory of Feshbach, Kerman, …

A 1-J laser was designed to launch light down 16, multi-mode fibers (400-{micro}m-core dia.). A diffractive-optic splitter was designed in collaboration with Digital Optics Corporation (DOC), and was delivered by DOC. Using this splitter, the energy injected into each fiber varied <1%. The spatial profile out of each fiber was such that there were no ''hot spots,'' a flyer could successfully be launched and a PETN pellet could be initiated. Preliminary designs of the system were driven by system efficiency where a pristine TEM{sub 00} laser beam would be required. The laser is a master oscillator, power amplifier (MOPA) consisting of a 4-mm-dia. Nd:YLF rod in the stable, q-switched oscillator and a 9.5-mm-dia. Nd:YLF rod in the double-passed amplifier. Using a TEM{sub 00} oscillator beam resulted in excellent transmission efficiencies through the fibers at lower energies but proved to be quite unreliable at higher energies, causing premature fiber damage, flyer plate rupture, stimulated Raman scattering (SRS), and stimulated Brillouin scattering (SBS). Upon further investigation, it was found that both temporal and spatial beam formatting of the laser were required to successfully initiate the PETN. Results from the single-mode experiments, including fiber damage, SRS and SBS losses, will be presented. In …

The environmentally benign, non-toxic, non-flammable fluids water and carbon dioxide (CO2) are the two most abundant and inexpensive solvents on earth. Emulsions of these fluids are of interest in many industrial processes, as well as CO2 sequestration and enhanced oil recovery. Until recently, formation of these emulsions required stabilization with fluorinated surfactants, which are expensive and often not environmentally friendly. In this work we overcame this severe limitation by developing a fundamental understanding of the properties of surfactants the CO2-water interface and using this knowledge to design and characterize emulsions stabilized with either hydrocarbon-based surfactants or nanoparticle stabilizers. We also discovered a new concept of electrostatic stabilization for CO2-based emulsions and colloids. Finally, we were able to translate our earlier work on the synthesis of silicon and germanium nanocrystals and nanowires from high temperatures and pressures to lower temperatures and ambient pressure to make the chemistry much more accessible.

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NCSA’s role in the SCIDAC Scalable Systems Software (SSS) project was to develop interfaces and communication mechanisms for systems monitoring, and to implement a prototype demonstrating those standards. The Scalable Systems Monitoring component of the SSS suite was designed to provide a large volume of both static and dynamic systems data to the components within the SSS infrastructure as well as external data consumers.

This report is part of a series of reports on building energy efficiency codes in countries associated with the Asian Pacific Partnership (APP) - Australia, South Korea, Japan, China, India, and the United States of America . This reports gives an overview of the development of building energy codes in Canada, including national energy policies related to building energy codes, history of building energy codes, recent national projects and activities to promote building energy codes. The report also provides a review of current building energy codes (such as building envelope, HVAC, lighting, and water heating) for commercial and residential buildings in Canada.

The formation of quantum computer test structures in silicon by ion implantation enables the characterization of spin readout mechanisms with ensembles of dopant atoms and the development of single atom devices. We briefly review recent results in the characterization of spin dependent transport and single ion doping and then discuss the diffusion and segregation behaviour of phosphorus, antimony and bismuth ions from low fluence, low energy implantations as characterized through depth profiling by secondary ion mass spectrometry (SIMS). Both phosphorus and bismuth are found to segregate to the SiO2/Si interface during activation anneals, while antimony diffusion is found to be minimal. An effect of the ion charge state on the range of antimony ions, 121Sb25+, in SiO2/Si is also discussed.

We report the discovery that impacts in the Stardust cometary collector are not distributed randomly in the collecting media, but appear to be clustered on scales smaller than {approx} 10 cm. We also report the discovery of at least two populations of oblique tracks. We evaluated several hypotheses that could explain the observations. No hypothesis was consistent with all the observations, but the preponderance of evidence points toward at least one impact on the central Whipple shield of the spacecraft as the origin of both clustering and low-angle oblique tracks. High-angle oblique tracks unambiguously originate from a non-cometary impact on the spacecraft bus just forward of the collector.

The Department of Energy Office of Nuclear Energy is supporting system studies to gain a better understanding of nuclear power's potential role in a hydrogen economy and what hydrogen production technologies show the most promise. This assessment includes identifying commercial hydrogen applications and their requirements, comparing the characteristics of nuclear hydrogen systems to those market requirements, evaluating nuclear hydrogen configuration options within a given market, and identifying the key drivers and thresholds for market viability of nuclear hydrogen options. One of the objectives of the current analysis phase is to determine how nuclear hydrogen technologies could evolve under a number of different futures. The outputs of our work will eventually be used in a larger hydrogen infrastructure and market analysis conducted for DOE-EE using a system-level market simulation tool now underway. This report expands on our previous work by moving beyond simple levelized cost calculations and looking at profitability, risk, and uncertainty from an investor's perspective. We analyze a number of technologies and quantify the value of certain technology and operating characteristics. Our model to assess the profitability of the above technologies is based on Real Options Theory and calculates the discounted profits from investing in each of the production …

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