Article describes study which investigates the hot corrosion behavior of Al0.1CoCrFeNi high entropy alloy (HEA) and Ni-base Alloy 718.

The production of a Higgs boson in association with a pair of t{bar t} or b{bar b} quarks plays a very important role at both the Tevatron and the Large Hadron Collider. The theoretical prediction of the corresponding cross sections has been improved by including the complete next-to-leading order QCD corrections. After a brief introduction, we review the results obtained for both the Tevatron and the Large Hadron Collider.

The following is an overview of results from ROA01-32 that focuses on an empirical method of calibrating stable seismic source moment-rate spectra derived from regional coda envelopes using broadband stations. The main goal was to develop a regional magnitude methodology that had the following properties: (1) it is tied to an absolute scale and is thus unbiased and transportable; (2) it can be tied seamlessly to the well-established teleseismic and regional catalogs; (3) it is applicable to small events using a sparse network of regional stations; (4) it is flexible enough to utilize S{sub n}-coda, L{sub g}-coda, or P-coda, whichever phase has the best signal-to-noise ratio. The results of this calibration yield source spectra and derived magnitudes that were more stable than any other direct-phase measure to date. Our empirical procedure accounted for all propagation, site, and S-to-coda transfer function effects. The resultant coda-derived moment-rate spectra were used to provide traditional band-limited magnitude (e.g., M{sub L}, m{sub b} etc.) as well as an unbiased, unsaturated magnitude (moment magnitude, M{sub w}) that is tied to a physical measure of earthquake size (i.e., seismic moment). We validated our results by comparing our coda-derived moment estimates with those obtained from long-period waveform modeling. …

The monitoring of nuclear explosions on a global basis requires accurate event locations. As an example, under the Comprehensive Test Ban Treaty, the size of an on-site inspection search area is 1,000 square kilometers or approximately 17 km accuracy assuming a circular area. This level of accuracy is a significant challenge for small events that are recorded using a sparse regional network. In such cases, the travel-time of seismic energy is strongly affected by crustal and upper mantle heterogeneity and large biases can result. This can lead to large systematic errors in location and, more importantly, to invalid error bounds associated with location estimates. Corrections can be developed and integrated to correct for these biases. These path corrections take the form of both three-dimensional model corrections along with three-dimensional empirically based travel time corrections. LLNL is currently working to integrate a diverse set of three-dimensional velocity model and empirical based travel-time products into one consistent and validated calibration set. To perform this task, we have developed a hybrid approach that uses three-dimensional model corrections for a region and then uses reference events when available to improve the path correction. This Bayesian kriging approach uses the best apriori three-dimensional velocity model …

We carried out a set of experiments on the Omega laser facility at Rochester with Laser MegaJoule (LMJ) like indirect drive irradiation. We studied the irradiation non-uniformity with the foam ball radiography technique and the implosion symmetry with (D{sub 2} + Argon) filled capsules core emission. Cylindrical ''Nova scale 1'' thin wall hohlraums were used. Forty of the Omega beams, arranged in three cones on each side of the hohlraum (5, 5, and lo), were used to create the X-ray drive. Eight additional beams were used on a Ti source to radiograph the foam balls. The shaped laser pulse was about 3 ns duration. The radiation drive was measured on each shot. The images were recorded with a 5 prn resolution Gated X-ray Imager coupled to a CCD camera.

Due to the planar construction of present x-ray streak tubes significant off-center defocusing is observed in both static and dynamic images taken with one-dimensional resolution slits. Based on the streak tube geometry curved photocathodes with radii of curvature ranging from 3.5 to 18 inches have been fabricated. We report initial off-center focusing performance data on the evaluation of these ''improved'' photocathodes in an X-ray streak camera and an update on the theoretical simulations to predict the optimum cathode curvature.

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The activities performed in verification of reactor fuel rods and assemblies by International Atomic Energy Agency (IAEA) safeguards inspectors include measurements of the length of the enriched uranium sections in fuel assemblies and fuel rods. These measurements are normally made with the IAEA hand-held gamma monitor (HM-4) on fuel elements containing only enriched uranium. Many fuel rods currently in use contain natural uranium end sections and several different {sup 235}U enrichment zones. To support development of standard procedures for IAEA nondestructive assay (NDA) measurements, a field measurement campaign was carried out to evaluate the FM-4 measurements and to investigate the feasibility of extending the HM-4 measurements to fuel rods and assemblies containing both natural and enriched uranium sections. The results show that the enriched fuel length can be measured to within {plus_minus} 1 to 2 cm in the presence of natural uranium sections and to within {plus_minus} 0.5 = when only enriched uranium is present. Based on the results from these measurements, a standard procedure, ``Measurement of Active Fuel Length in Fuel Assemblies and Fuel Rods Using the HM-4,`` has been drafted for review by the IAEA.

The activities performed in verification of reactor fuel rods and assemblies by International Atomic Energy Agency (IAEA) safeguards inspectors include measurements of the length of the enriched uranium sections in fuel assemblies and fuel rods. These measurements are normally made with the IAEA hand-held gamma monitor (HM-4) on fuel elements containing only enriched uranium. Many fuel rods currently in use contain natural uranium end sections and several different [sup 235]U enrichment zones. To support development of standard procedures for IAEA nondestructive assay (NDA) measurements, a field measurement campaign was carried out to evaluate the FM-4 measurements and to investigate the feasibility of extending the HM-4 measurements to fuel rods and assemblies containing both natural and enriched uranium sections. The results show that the enriched fuel length can be measured to within [plus minus] 1 to 2 cm in the presence of natural uranium sections and to within [plus minus] 0.5 = when only enriched uranium is present. Based on the results from these measurements, a standard procedure, Measurement of Active Fuel Length in Fuel Assemblies and Fuel Rods Using the HM-4,'' has been drafted for review by the IAEA.

Recent developments in six areas of tandem-mirror theory are explored. Specifically, FLR terms (including electric-field drift) have been added to our 3-D paraxial MHD equilibrium code. Our low-frequency MHD stability analysis with FLR, which previously included only m/sub theta/ = 1 rigid perturbations, has been extended to incorporate moderate m/sub theta/, rotational drive, finite-beta effects on wall stabilization, and the well-digging effect of energetic electrons by using three computational techniques. In addition, we have examined the microstability of relativistic electrons with a loss-cone distribution, emphasizing the whistler and cyclotron-maser instabilities. We have also studied techniques for controlling radial transport, including the floating of segmented end plates and the tuning of transition-region coils, and have quantified the residual transport in a tandem mirror with axisymmetric throttle coils. Earlier work on the effect of ECRH on potentials in thermal-barrier cells has been extended. The transition between the weak- and strong-heating regimes has been examined using Fokker-Planck and Monte Carlo codes; an analytic model for the potentials relative to the end wall has been developed. Finally, our investigation of drift-frequency pumping of thermal-barrier ions has demonstrated that pumping is optimized when the magnetic fluctuation is perpendicular to both the unperturbed field and the …

A wide range of phenomena is observed in heavy-ion collisions, calling for a comprehensive theory based on fundamental principles of many-particle quantum mechanics. At low energies, the nuclear dynamics is controlled by the mean field, as we know from spectroscopic nuclear physics. We therefore expect the comprehensive theory of collisions to contain mean-field theory at low energies. The mean-field theory is the subject of the first lectures in this chapter. This theory can be studied quantum mechanically, in which form it is called TDHF (time-dependent Hartree-Fock), or classically, where the equation is called the Vlasov equation. 25 references, 14 figures.

The basis for the study of the evolution of a shocked interface stems from the question of the Rayleigh-Taylor (RT) instability (Taylor 1950). Starting in the late 18th century, the stability of an interface submitted to gravitational forces was investigated for the case in which the density of one of the materials across the interface was negligible compared to the other. Taylor analyzed the case in which the Atwood number (ratio of the difference of the densities to their sum) is less than 1, and the acceleration of the system is constant. He determined that the interface was unstable to small perturbations only if the direction of the acceleration normal to the interface coincides with that of the density gradient. Richtmyer (1960) extended Taylor's analysis to the case of an implusive acceleration. His results implied that the interface would be unstable irrespective of the relative orientation of the velocity impulse and the density gradient. His predictions were verified experimentally by Meshkov (1969), and the Richtmyer-Meshkov (RM) instability became a subject of research in its own right. Experimental, numerical, and theoretical works address this problem. The RM problem has been studied with both the shock-tube and laser experiments. In this paper, …

Newly developed multilayer-based mirrors and optical elements enable the imaging of high-resolution structure and ultrafast dynamics of samples with the soft X-ray free electron laser, FLASH, at DESY in Hamburg. The FLASH free-electron laser (FEL) produces intense ultrashort soft X-ray pulses with more than 10{sup 8} times higher peak brightness as compared with the most advanced synchrotron radiation sources. This allows time-resolved X-ray imaging and holography of nanostructures with a temporal resolution approaching 10 fs, opening up new studies of laser-matter interactions and the dynamics of correlated systems. In addition, the ultrafast pulses can be used to obtain structural data before the onset of radiation damage. This vastly increases the dose that can be used to record images of biological samples and hence improving the resolution of images. The extreme power of the X-ray pulses poses a challenge, and new methods are required to harness them. The methods developed here will also pave the way to imaging at upcoming hard-X-ray FELs. With those sources, atomic-resolution imaging of single uncrystallized macromolecules may become possible. In the first demonstration of ultrafast X-ray imaging at FLASH, a micron-sized test object was illuminated by a single focused coherent FEL pulse (Fig. 1). The coherent …

This article investigates the association between CYP2D6 genotype and the risk of antidepressant discontinuation, dosage modification, and the occurrence of maternal CYP2D6, Antidepressants, Depression during pregnancy.

This article describes the isolation and genomic characterization of 46 phages from environmental samples at various geographic locations in the U.S. infecting a single Arthrobacter sp. strain.

A new rapid separation method for radiostrontium in emergency milk samples was developed at the Savannah River Site (SRS) Environmental Bioassay Laboratory (Aiken, SC, USA) that will allow rapid separation and measurement of Sr-90 within 8 hours. The new method uses calcium phosphate precipitation, nitric acid dissolution of the precipitate to coagulate residual fat/proteins and a rapid strontium separation using Sr Resin (Eichrom Technologies, Darien, IL, USA) with vacuum-assisted flow rates. The method is much faster than previous method that use calcination or cation exchange pretreatment, has excellent chemical recovery, and effectively removes beta interferences. When a 100 ml sample aliquot is used, the method has a detection limit of 0.5 Bq/L, well below generic emergency action levels.

The authors present a straightforward method for the inclusion of quantum nuclear vibrational effects in molecular dynamics calculations of shock Hugoniot temperatures. Using a grueneisen equation of state and a quasi-harmonic approximation to the vibrational energies, they derive a simple, post-processing method for calculation of the quantum corrected Hugoniot temperatures. They have used our novel technique on ab initio simulations of both shock compressed water and methane. Our results indicate significantly closer agreement with all available experimental temperature data for these two systems. Our formalism and technique can be easily applied to a number of different shock compressed molecular liquids or covalent solids, and has the potential to decrease the large uncertainties inherent in many experimental Hugoniot temperature measurements of these systems.

Inter-plant concentration ratios (IPCR), [Bq g{sup -1} {sup 137}Cs in coral atoll tree food-crops/Bq g{sup -1} {sup 137}Cs in leaves of native plant species whose roots share a common soil volume], can replace transfer factors (TF) to predict {sup 137}Cs concentration in tree food-crops in a contaminated area with an aged source term. The IPCR strategy has significant benefits relative to TF strategy for such purposes in the atoll ecosystem. IPCR strategy applied to specific assessments takes advantage of the fact tree roots naturally integrate 137Cs over large volumes of soil. Root absorption of {sup 137}Cs replaces large-scale, expensive soil sampling schemes to reduce variability in {sup 137}Cs concentration due to inhomogeneous radionuclide distribution. IPCR [drinking-coconut meat (DCM)/Scaevola (SCA) and Tournefortia (TOU) leaves (native trees growing on all atoll islands)] are log normally distributed (LND) with geometric standard deviation (GSD) = 1.85. TF for DCM from Enewetak, Eneu, Rongelap and Bikini Atolls are LND with GSD's of 3.5, 3.0, 2.7, and 2.1, respectively. TF GSD for Rongelap copra coconut meat is 2.5. IPCR of Pandanus fruit to SCA and TOU leaves are LND with GSD = 1.7 while TF GSD is 2.1. Because IPCR variability is much lower than TF …

Lattice level measurements of material response under extreme conditions are required to build a phenomenological understanding of the shock response of solids. We have successfully used laser produced plasma x-ray sources coincident with laser driven shock waves to make in-situ measurements of the lattice response during shock compression for both single crystal and polycrystalline materials. Using a detailed analysis of shocked single crystal iron which has undergone the {alpha} - {var_epsilon} phase transition we can constrain the transition mechanism to be consistent with a compression and shuffle of alternate lattice planes.

Precise gamma-ray thermal neutron capture cross sectionshave been measured at the Budapest Reactor for all elements withZ=1-83,92 except for He and Pm. These measurements and additional datafrom the literature been compiled to generate the Evaluated Gamma-rayActivation File (EGAF), which is disseminated by LBNL and the IAEA. Thesedata are nearly complete for most isotopes with Z<20 so the totalradiative thermal neutron capture cross sections can be determineddirectly from the decay scheme. For light isotopes agreement with therecommended values is generally satisfactory although large discrepanciesexist for 11B, 12,13C, 15N, 28,30Si, 34S, 37Cl, and 40,41K. Neutroncapture decay data for heavier isotopes are typically incomplete due tothe contribution of unresolved continuum transitions so only partialradiative thermal neutron capture cross sections can be determined. Thecontribution of the continuum to theneutron capture decay scheme arisesfrom a large number of unresolved levels and transitions and can becalculated by assuming that the fluctuations in level densities andtransition probabilities are statistical. We have calculated thecontinuum contribution to neutron capture decay for the palladiumisotopes with the Monte Carlo code DICEBOX. These calculations werenormalized to the experimental cross sections deexciting low excitationlevels to determine the total radiative thermal neutron capture crosssection. The resulting palladium cross sections values were determinedwith a precision …

Numerical models of geologic storage of carbon dioxide (CO2)in brine-bearing formations use characteristic curves to represent theinteractions of non-wetting-phase CO2 and wetting-phase brine. When aproblem includes both injection of CO2 (a drainage process) and itssubsequent post-injection evolution (a combination of drainage andwetting), hysteretic characteristic curves are required to correctlycapture the behavior of the CO2 plume. In the hysteretic formulation,capillary pressure and relative permeability depend not only on thecurrent grid-block saturation, but also on the history of the saturationin the grid block. For a problem that involves only drainage or onlywetting, a non-hysteretic formulation, in which capillary pressure andrelative permeability depend only on the current value of the grid-blocksaturation, is adequate. For the hysteretic formulation to be robustcomputationally, care must be taken to ensure the differentiability ofthe characteristic curves both within and beyond the turning-pointsaturations where transitions between branches of the curves occur. Twoexample problems involving geologic CO2 storage are simulated withTOUGH2, a multiphase, multicomponent code for flow and transport codethrough geological media. Both non-hysteretic and hysteretic formulationsare used, to illustrate the applicability and limitations ofnon-hysteretic methods.The first application considers leakage of CO2from the storage formation to the ground surface, while the secondexamines the role of heterogeneity within the storageformation.

The Nevada Test Site (NTS) is a test bed for implementation of the Safeguards First Principles Initiative (SFPI), a risk-based approach to Material Control & Accountability (MC&A) requirements. The Comprehensive Assessment of Safeguards Strategies (COMPASS) model is used to determine the effectiveness of safeguards systems under SFPI. Under this model, MC&A is divided into nine primary elements. Each element is divided into sub-elements. Then, each sub-element is assigned two values, effectiveness and contribution, that are used to calculate the rating. Effectiveness is a measure of sub-element implementation and how well it meets requirements. Contribution is a relative measure of the importance, and functions as a weighting factor. The COMPASS model provides the methodology for calculation of element and subelement, but not the actual criteria. Each site must develop its own criteria. For the rating to be meaningful, the effectiveness criteria must be objective and based on explicit, measurable criteria. Contribution (weights) must reflect the importance within the MC&A program. This paper details the NTS approach to system effectiveness and contribution values, and will cover the following: the basis for the ratings, an explanation of the contribution weights, and the objective, performance-based effectiveness criteria. Finally, the evaluation process will be described.

The EBIT spectroscopy that now seems routine would not be possible without considerable good luck in several areas of EBIT technology. Among these are x-ray background, ion cooling, neutral gas density, and electron current density and energy control. A favourable outcome in these areas has enabled clean x-ray spectra, sufficient intensity for high resolution spectroscopy, production of very high charge states, and a remarkable variety of spectroscopic measurements. During construction of the first EBIT 20 years ago, it was not clear that any of this was possible.

An important milestone was passed this year when the fraction of the world's population living in cities exceeded 50%. This shift from the countryside to urban areas is certain to continue and, for many, the destination will be large cities. Already there are over 400 cities with populations greater than one million inhabitants and twenty cities with populations greater than ten million inhabitants. With a growing fraction of the population living in an urban environment, the unique aspects of an urban climate also rise in importance. These include features like air pollution and increased humidity. Another unique feature of the urban climate is the phenomenon of the urban heat island. The urban heat island phenomenon was first observed over one hundred years ago in northern latitude cities, where the city centers were slightly warmer than the suburbs. (Instantaneous communications probably played a role in its identification, much as it did for other weather-related events.) For these cities, a heat island was generally a positive effect because it resulted in reduced heating requirements during the winters. It was only in the 1960s, as air conditioning and heavy reliance on automobiles grew, that the negative impacts of heat islands became apparent. The …