The objective of this research program was to take a highly multidisciplinary approach to define the biogeochemical factors that control technetium (Tc) mobility in FRC sediments. The aim was to use batch and column studies to probe the biogeochemical conditions that control the mobility of Tc at the FRC. Background sediment samples from Area 2 (pH 6.5, low nitrate, low {sup 99}Tc) and Area 3 (pH 3.5, high nitrate, relatively high {sup 99}Tc) of the FRC were selected (http://www.esd.ornl.gov/nabirfrc). For the batch experiments, sediments were mixed with simulated groundwater, modeled on chemical constituents of FRC waters and supplemented with {sup 99}Tc(VII), both with and without added electron donor (acetate). The solubility of the Tc was monitored, alongside other biogeochemical markers (nitrate, nitrite, Fe(II), sulfate, acetate, pH, Eh) as the 'microcosms' aged. At key points, the microbial communities were also profiled using both cultivation-dependent and molecular techniques, and results correlated with the geochemical conditions in the sediments. The mineral phases present in the sediments were also characterized, and the solid phase associations of the Tc determined using sequential extraction and synchrotron techniques. In addition to the batch sediment experiments, where discrete microbial communities with the potential to reduce and precipitate {sup …

Concentrator photovoltaics may play significant role in growth of solar electricity because of scalability. Need to take a bird?s eye view for the design and a worm?s eye view for diagnosis.

The purpose of this Workshop on ''Functional Requirements for the Modeling of Fate and Transport of Waterborne CBRN Materials'' was to solicit functional requirements for tools that help Incident Managers plan for and deal with the consequences of industrial or terrorist releases of materials into the nation's waterways and public water utilities. Twenty representatives attended and several made presentations. Several hours of discussions elicited a set of requirements. These requirements were summarized in a form for the attendees to vote on their highest priority requirements. These votes were used to determine the prioritized requirements that are reported in this paper and can be used to direct future developments.

Protein transport across hydrophobic membranes that partition cellular compartments is essential in all cells. The twin arginine translocation (Tat) pathway transports proteins across the prokaryotic cytoplasmic membranes. Distinct from the universally conserved Sec pathway, which secretes unfolded proteins, the Tat machinery is unique in that it secretes proteins in a folded conformation, making it an attractive pathway for the transport and secretion of heterologously expressed proteins that are Sec-incompatible. During the past 7 years, the DOE-supported project has focused on the characterization of the diversity of bacterial and archaeal Tat substrates as well as on the characterization of the Tat pathway of a model archaeon, Haloferax volcanii, a member of the haloarchaea. We have demonstrated that H. volcanii uses this pathway to transport most of its secretome.

Under the Nuclear/Radiological Incident Annex of the National Response Framework, the U.S. Department of Energy (DOE) has specific responsibilities as a coordinating agency and for leading interagency response elements in the Federal Radiological Monitoring and Assessment Center (FRMAC). Emergency response planning focuses on rapidly providing response elements in stages after being notified of a nuclear/radiological incident. The use of Home Teams during the field team deployment period and recent advances in collecting and transmitting data from the field directly to assessment assets has greatly improved incident assessment times for public protection decisions. The DOE’s Remote Sensing Laboratory (RSL) based in Las Vegas, Nevada, has successfully deployed technical and logistical support for this mission at national exercises such as Top Officials Exercise IV (TOPOFF IV). In a unique response situation, DOE will provide advance contingency support to NASA during the scheduled launch in the fall of 2009 of the Mars Science Laboratory (MSL). The MSL rover will carry a radioisotope power system that generates electricity from the heat of plutonium’s radioactive decay. DOE assets and contingency planning will provide a pre-incident response posture for rapid early plume phase assessment in the highly unlikely launch anomaly.

Plant mounds or blow-sand mounds are accumulations of soil particles and plant debris around the base of shrubs and are common features in deserts in the southwestern United States. An important factor in their formation is that shrubs create surface roughness that causes wind-suspended particles to be deposited and resist further suspension. Shrub mounds occur in some plant communities on the Nevada Test Site, the Nevada Test and Training Range (NTTR), and Tonopah Test Range (TTR), including areas of surface soil contamination from past nuclear testing. In the 1970s as part of early studies to understand properties of actinides in the environment, the Nevada Applied Ecology Group (NAEG) examined the accumulation of isotopes of Pu, 241Am, and U in plant mounds at safety experiment and storage-transportation test sites of nuclear devices. Although aerial concentrations of these contaminants were highest in the intershrub or desert pavement areas, the concentration in mounds were higher than in equal volumes of intershrub or desert pavement soil. The NAEG studies found the ratio of contaminant concentration of actinides in soil to be greater (1.6 to 2.0) in shrub mounds than in the surrounding areas of desert pavement. At Project 57 on the NTTR, 17 percent …

This document summarizes the findings of the Accelerator Working Group (AWG) of the International Scoping Study (ISS) of a Future Neutrino Factory and Superbeam Facility. The work of the group took place at three plenary meetings along with three workshops, and an oral summary report was presented at the NuFact06 workshop held at UC-Irvine in August, 2006. The goal was to reach consensus on a baseline design for a Neutrino Factory complex. One aspect of this endeavor was to examine critically the advantages and disadvantages of the various Neutrino Factory schemes that have been proposed in recent years.

Many of the important challenges facing humanity, including developing alternative sources of energy and improving health, are being addressed by advances that demand the improved understanding and control of matter. While the visualization, exploration, and manipulation of macroscopic matter have long been technological goals, scientific developments in the twentieth century have focused attention on understanding matter on the atomic scale through the underlying framework of quantum mechanics. Of special interest is matter that consists of natural or artificial nanoscale building blocks defined either by atomic structural arrangements or by electron or spin formations created by collective correlation effects (Figure 1.1). The essence of the challenge to the scientific community has been expressed in five grand challenges for directing matter and energy recently formulated by the Basic Energy Sciences Advisory Committee [1]. These challenges focus on increasing our understanding of, and ultimately control of, matter at the level of atoms, electrons. and spins, as illustrated in Figure 1.1, and serve the entire range of science from advanced materials to life sciences. Meeting these challenges will require new tools that extend our reach into regions of higher spatial, temporal, and energy resolution. X-rays with energies above 10 keV offer capabilities extending beyond …

Dramatic advances in data management have been made as a result of the Paperless FRMAC initiative, sponsored by the DOE’s Office of Emergency Response (NA-42). The FRMAC (Federal Radiological Monitoring and Assessment Center) is the hub for all radiological monitoring and the production of data products that interpret those measurements in terms of protective action guidelines. As such, very large amounts of data must be quickly assimilated from numerous sources and then widely distributed as graphical interpretations as fast as possible. Paperless FRMAC is a broad initiative to move that data faster, farther and better through telemetry, automation, and networking. This discussion reviews for the first time the status of the now two-year-old Paperless FRMAC initiative. Key features of Paperless FRMAC include multipath telemetry of measurements from DOE field teams, 24/7 Internet presence, early data entry by first responders, support for distance collaborations, and data exchange with the EPA’s SCRIBE database. The heart of the enterprise is the RAMS database, which provides seamless interfacing with GIS, LIMS, and TurboFRMAC for calculations. Paperless FRMAC is presented to users via two Internet websites. The first, FRMAC Portal website, is restricted to the emergency responders for data input, analysis, and product development. The …

Better to understand the status of fusion research in the year 2003 we will first put the research in its historical context. Fusion power research, now beginning its sixth decade of continuous effort, is unique in the field of scientific research. Unique in its mixture of pure and applied research, unique in its long-term goal and its promise for the future, and unique in the degree that it has been guided and constrained by national and international governmental policy. Though fusion research's goal has from the start been precisely defined, namely, to obtain a net release of energy from controlled nuclear fusion reactions between light isotopes (in particular those of hydrogen and helium) the difficulty of the problem has spawned in the past a very wide variety of approaches to the problem. Some of these approaches have had massive international support for decades, some have been pursued only at a ''shoestring'' level by dedicated groups in small research laboratories or universities. In discussing the historical and present status of fusion research the implications of there being two distinctly different approaches to achieving net fusion power should be pointed out. The first, and oldest, approach is the use of strong magnetic …

In this paper we propose a novel visibility-culling technique for optimizing the computation and rendering of opaque isosurfaces. Given a continuous scalar field f (x) over a domain D and an isovalue w, our technique exploits the continuity of f to determine conservative visibility bounds implicitly, i.e., without the need for actually computing the isosurface f{sup -1}(w). We generate Implicit Occluders based on the change in sign of f *(x) = f (x)-w, from positive to negative (or vice versa) in the neighborhood of the isosurface. Consider, for example, the sign of f * along a ray r cast from the current viewpoint. The first change in sign of f * within D must contain an intersection of r with the isosurface. Any additional intersection of the isosurface with r is not visible. Implicit Occluders constitute a general concept that can be exploited algorithmically in different ways depending on the framework adopted for visibility computations. In this paper, we propose a simple from-point approach that exploits well-known hardware occlusion queries.

The mobilization of arsenic was examined in a system where the deposition of iron and arsenic have been substantially modified by large-scale manipulations. This engineering practice was designed to decrease arsenic concentrations in water supplied to the City of Los Angeles. Accomplishing this objective, however, has resulted in significant accumulation of arsenic and iron in the sediments of a reservoir on the Los Angeles Aqueduct. Arsenic and iron are released into the porewater at depth in the sediment, consistent with reductive dissolution of iron(III) oxyhydroxides. Factors influencing the possible re-sorption of arsenic onto residual iron(III) oxyhydroxides solids have been examined. Reduction of As(V) to As(III) alone cannot account for arsenic mobilization since arsenic occurs in the solid phase as As(III) well above the depth at which it is released into the porewater. Competition from other porewater constituents could suppress re-sorption of arsenic released by reductive dissolution.

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The present paper reports the results of an attempt aimed at the synthesis of element 118 in the reaction {sup 249}Cf({sup 48}Ca,3n){sup 294}118. The experiment was performed employing the Dubna Gas-filled Recoil Separator and the U400 heavy-ion cyclotron at FLNR, JINR, Dubna. In the course of a 2300-hour irradiation of an enriched {sup 249}Cf target (0.23 mg/cm{sup 2}) with a beam of 245-MeV {sup 48}Ca ions, we accumulated a total beam dose of 2.5 x 10{sup 19} ions. We detected two events that may be attributed to the formation and decay of nuclei with Z=118. For one event, we observed a decay chain of two correlated {alpha}-decays with corresponding energies and correlation times of E{sub {alpha}1} = 11.65 {+-} 0.06 MeV, t{sub {alpha}1} = 2.55 ms and E{sub {alpha}2} = 10.71 {+-} 0.17 MeV, t{sub {alpha}2} = 42.1 ms and, finally, a spontaneous fission with the sum of the kinetic energies of the fission fragments E{sub tot} = 207 MeV (TKE {approx} 230 MeV) and t{sub SF} = 0.52 s. In the second event chain, the recoil nucleus decayed into two fission fragments with E{sub tot} = 223 MeV (TKE {approx} 245 MeV) 3.16 ms later, without intervening {alpha} decays. …

The compressibility of fluid deuterium up to several Mbar has been probed using laser-driven shock waves reflected from a quartz anvil. Combining high-precision ({approx} 1 %) shock velocity measurements with the double-shock technique, where differences in equation of state (EOS) models are magnified, has allowed us to accurately discriminate between various theoretical predictions. Our data are consistent with EOS models that show approximately fourfold compression on the principal Hugoniot from 0.7 to 1 Mbar; however, our results indicate that deuterium has a higher compressibility than predicted by these models for single shock pressures between 1 and 2.5 Mbar.

We present a simple method for compressing very large and regularly sampled scalar fields. Our method is particularly attractive when the entire data set does not fit in memory and when the sampling rate is high relative to the feature size of the scalar field in all dimensions. Although we report results for R{sup 3} and R{sup 4} data sets, the proposed approach may be applied to higher dimensions. The method is based on the new Lorenzo predictor, introduced here, which estimates the value of the scalar field at each sample from the values at processed neighbors. The predicted values are exact when the n-dimensional scalar field is an implicit polynomial of degree n-1. Surprisingly, when the residuals (differences between the actual and predicted values) are encoded using arithmetic coding, the proposed method often outperforms wavelet compression in an L{infinity} sense. The proposed approach may be used both for lossy and lossless compression and is well suited for out-of-core compression and decompression, because a trivial implementation, which sweeps through the data set reading it once, requires maintaining only a small buffer in core memory, whose size barely exceeds a single n-1 dimensional slice of the data.

Differentiating erythroid cells execute a unique gene expression program that insures synthesis of the appropriate proteome at each stage of maturation. Standard expression microarrays provide important insight into erythroid gene expression but cannot detect qualitative changes in transcript structure, mediated by RNA processing, that alter structure and function of encoded proteins. We analyzed stage-specific changes in the late erythroid transcriptome via use of high-resolution microarrays that detect altered expression of individual exons. Ten differentiation-associated changes in erythroblast splicing patterns were identified, including the previously known activation of protein 4.1R exon 16 splicing. Six new alternative splicing switches involving enhanced inclusion of internal cassette exons were discovered, as well as 3 changes in use of alternative first exons. All of these erythroid stage-specific splicing events represent activated inclusion of authentic annotated exons, suggesting they represent an active regulatory process rather than a general loss of splicing fidelity. The observation that 3 of the regulated transcripts encode RNA binding proteins (SNRP70, HNRPLL, MBNL2) may indicate significant changes in the RNA processing machinery of late erythroblasts. Together, these results support the existence of a regulated alternative pre-mRNA splicing program that is critical for late erythroid differentiation.

A group of fusion safety professionals contribute to a Joint Working Group (JWG) that performs occupational safety walkthroughs of US and Japanese fusion experiments on a routine basis to enhance the safety of visiting researchers. The most recent walkthrough was completed in Japan in March 2008 by the US Safety Monitor team. This paper gives the general conclusions on fusion facility personnel safety that can be drawn from the series of walkthroughs.

It is anticipated that in the near future disk storage systems will surpass application servers and will become the primary consumer of power in the data centers. Shutting down of inactive disks is one of the more widespread solutions to save power consumption of disk systems. This solution involves spinning down or completely shutting off disks that exhibit long periods of inactivity and placing them in standby mode. A file request from a disk in standby mode will incur an I/O cost penalty as it takes time to spin up the disk before it can serve the file. In this paper, we address the problem of designing and implementing file allocation strategies on disk storage that save energy while meeting performance requirements of file retrievals. We present an algorithm for solving this problem with guaranteed bounds from the optimal solution. Our algorithm runs in O(nlogn) time where n is the number of files allocated. Detailed simulation results and experiments with real life workloads are also presented.

The Linac Coherent Light Source (LCLS) is an x-ray Free-Electron Laser (FEL) project presently in a commissioning phase at SLAC. We report here on very low emittance measurements made at low bunch charge, and a few femtosecond bunch length produced by the LCLS bunch compressors. Start-to-end simulations associated with these beam parameters show the possibilities of generating hundreds of GW at 1.5 {angstrom} x-ray wavelength and nearly a single longitudinally spike at 1.5 nm with 2-fs duration.

Background, Aim and Scope. In 2005 a comprehensive comparison of LCIA toxicity characterisation models was initiated by the UNEP-SETAC Life Cycle Initiative, directly involving the model developers of CalTOX, IMPACT 2002, USES-LCA, BETR, EDIP, WATSON, and EcoSense. In this paper we describe this model-comparison process and its results--in particular the scientific consensus model developed by the model developers. The main objectives of this effort were (i) to identify specific sources of differences between the models' results and structure, (ii) to detect the indispensable model components, and (iii) to build a scientific consensus model from them, representing recommended practice. Methods. A chemical test set of 45 organics covering a wide range of property combinations was selected for this purpose. All models used this set. In three workshops, the model comparison participants identified key fate, exposure and effect issues via comparison of the final characterisation factors and selected intermediate outputs for fate, human exposure and toxic effects for the test set applied to all models. Results. Through this process, we were able to reduce inter-model variation from an initial range of up to 13 orders of magnitude down to no more than 2 orders of magnitude for any substance. This led to …

This project produced algorithms for and software implementations of adaptive mesh refinement (AMR) methods for solving practical solid and thermal mechanics problems on multiprocessor parallel computers using unstructured finite element meshes. The overall goal is to provide computational solutions that are accurate to some prescribed tolerance, and adaptivity is the correct path toward this goal. These new tools will enable analysts to conduct more reliable simulations at reduced cost, both in terms of analyst and computer time. Previous academic research in the field of adaptive mesh refinement has produced a voluminous literature focused on error estimators and demonstration problems; relatively little progress has been made on producing efficient implementations suitable for large-scale problem solving on state-of-the-art computer systems. Research issues that were considered include: effective error estimators for nonlinear structural mechanics; local meshing at irregular geometric boundaries; and constructing efficient software for parallel computing environments.

As safety professionals, we strive to implement a robust safety process in our organizations to maximize worker protection. We sell our philosophy and ideas to senior management, and then work with line management and the work force to develop and implement the safety process. Through this effort, we are likely to accomplish two major objectives. First, we obtain buy-in from line management and the workers, maybe even ownership for the safety process we implement. Second, we increase the likelihood that the hazards (and necessary controls) associated with the work activities performed by our workforce are identified and addressed by the safety process we implement. Our ambition is to maximize safety and health in the work place, and prevent injuries. Realizing this goal improves overall business operations. Petersen suggests an accident is an indication of something wrong in the management system (Petersen, pg 15). Successful organizations operate with the safety process fully integrated into the management system. If the management system fails, the safety process has failed the worker. As safety professionals, we must ask ourselves whether we did our job adequately. The better organizations strive for continuous improvement. The overall success of safety processes, in terms of accident and injury …

We use high-resolution N-body numerical simulations to study the number of predicted large-separation multiply-imaged systems produced by clusters of galaxies in the SDSS photometric and spectroscopic quasar samples. We incorporate the condensation of baryons at the center of clusters by (artificially) adding a brightest central galaxy (BCG) as a truncated isothermal sphere. We make predictions in two at cosmological models: a {Lambda}CDM model with a matter density {Omega}{sub m,0} = 0.3, and {sigma}{sub 8} 0.9 ({Lambda}CDM0), and a model favored by the WMAP three-year data with {Omega}{sub m,0} = 0.238, and {sigma}{sub 8} = 0.74 (WMAP3). We found that the predicted multiply-imaged quasars with separation > 10 is about 6.2 and 2.6 for the SDSS photometric (with an effective area 8000 deg{sup 2}) and spectroscopic (with an effective area 5000 deg{sup 2}) quasar samples respectively in the {Lambda}CDM0 model; the predicted numbers of large-separation lensed quasars agree well with the observations. These numbers are reduced by a factor of 7 or more in the WMAP3 model, and are consistent with data at {approx}< 8% level. The predicted cluster lens redshift peaks around redshift 0.5, and 90% are between 0.3 and 1. The ratio of systems with at least four image …