Experimental results are reported from two measurementtechniques (semiconductor switching and electro-optic sampling) thatallow temporal characterization of electron bunches produced by alaser-driven plasma-based accelerator. As femtosecond electron bunchesexit the plasma-vacuum interface, coherent transition radiation (at THzfrequencies) is emitted. Measuring the properties of this radiationallows characterization of the electron bunches. Theoretical work on theemission mechanism is represented, including a model that calculates theTHz waveform from a given bunch profile. It is found that the spectrum ofthe THz pulse is coherent up to the 200 mu m thick crystal (ZnTe)detection limit of 4 THz, which corresponds to the production of sub-50fs (root-mean-square) electron bunch structure. The measurementsdemonstrate both the shot-to-shot stability of bunch parameters that arecritical to THz emission (such as total charge and bunch length), as wellas femtosecond synchrotron between bunch, THz pulse, and laserbeam.

The Center for Extended Magnetohydrodynamic Modeling (CEMM) is developing computer simulation models for predicting the behavior of magnetically confined plasmas. Over the first phase of support from the Department of Energy’s Scientific Discovery through Advanced Computing (SciDAC) initiative, the focus has been on macroscopic dynamics that alter the confinement properties of magnetic field configurations. The ultimate objective is to provide computational capabilities to predict plasma behavior—not unlike computational weather prediction—to optimize performance and to increase the reliability of magnetic confinement for fusion energy. Numerical modeling aids theoretical research by solving complicated mathematical models of plasma behavior including strong nonlinear effects and the influences of geometrical shaping of actual experiments. The numerical modeling itself remains an area of active research, due to challenges associated with simulating multiple temporal and spatial scales. The research summarized in this report spans computational and physical topics associated with state of the art simulation of magnetized plasmas. The tasks performed for this grant are categorized according to whether they are primarily computational, algorithmic, or application-oriented in nature. All involve the development and use of the Non-Ideal Magnetohydrodynamics with Rotation, Open Discussion (NIMROD) code, which is described at http://nimrodteam.org. With respect to computation, we have tested and …

TMVOC-MP is a massively parallel version of the TMVOC code (Pruess and Battistelli, 2002), a numerical simulator for three-phase non-isothermal flow of water, gas, and a multicomponent mixture of volatile organic chemicals (VOCs) in multidimensional heterogeneous porous/fractured media. TMVOC-MP was developed by introducing massively parallel computing techniques into TMVOC. It retains the physical process model of TMVOC, designed for applications to contamination problems that involve hydrocarbon fuels or organic solvents in saturated and unsaturated zones. TMVOC-MP can model contaminant behavior under 'natural' environmental conditions, as well as for engineered systems, such as soil vapor extraction, groundwater pumping, or steam-assisted source remediation. With its sophisticated parallel computing techniques, TMVOC-MP can handle much larger problems than TMVOC, and can be much more computationally efficient. TMVOC-MP models multiphase fluid systems containing variable proportions of water, non-condensible gases (NCGs), and water-soluble volatile organic chemicals (VOCs). The user can specify the number and nature of NCGs and VOCs. There are no intrinsic limitations to the number of NCGs or VOCs, although the arrays for fluid components are currently dimensioned as 20, accommodating water plus 19 components that may be either NCGs or VOCs. Among them, NCG arrays are dimensioned as 10. The user may select …

Although electrokinetic effects are not new, only recently have they been investigated for possible use in energy conversion devices. We have recently reported the electrokinetic generation of molecular hydrogen from rapidly flowing liquid water microjets [Duffin et al. JPCC 2007, 111, 12031]. Here, we describe the use of liquid water microjets for direct conversion of electrokinetic energy to electrical power. Previous studies of electrokinetic power production have reported low efficiencies ({approx}3%), limited by back conduction of ions at the surface and in the bulk liquid. Liquid microjets eliminate energy dissipation due to back conduction and, measuring only at the jet target, yield conversion efficiencies exceeding 10%.

This sampling and analysis instruction (SAI) provides the requirements for sample collection and laboratory analysis to evaluate the extent of hexavalent chromium contamination present in the soil below the 100-C-7 and 100-C-7:1 remedial action waste site excavations.

An over-dense microwave driven ion source capable ofproducing deuterium (or hydrogen) beams at 100-200 mA/cm2 and with atomicfraction>90 percent was designed and tested with an electrostaticlow energy beam transport section (LEBT). This ion source wasincorporatedinto the design of an Accelerator Driven Neutron Source(ADNS). The other key components in the ADNS include a 6 MeV RFQaccelerator, a beam bending and scanning system, and a deuterium gastarget. In this design a 40 mA D+ beam is produced from a 6 mm diameteraperture using a 60 kV extraction voltage. The LEBT section consists of 5electrodes arranged to form 2 Einzel lenses that focus the beam into theRFQ entrance. To create the ECR condition, 2 induction coils are used tocreate ~; 875 Gauss on axis inside the source chamber. To prevent HVbreakdown in the LEBT a magnetic field clamp is necessary to minimize thefield in this region. Matching of the microwave power from the waveguideto the plasma is done by an autotuner. We observed significantimprovement of the beam quality after installing a boron nitride linerinside the ion source. The measured emittance data are compared withPBGUNS simulations.

Stimulated sulfate-reduction is a bioremediation technique utilized for the sequestration of heavy metals in the subsurface.We performed laboratory column experiments to investigate the geoelectrical response of iron sulfide transformations by Desulfo vibriovulgaris. Two geoelectrical methods, (1) spectral induced polarization (SIP), and (2) electrodic potential measurements, were investigated. Aqueous geochemistry (sulfate, lactate, sulfide, and acetate), observations of precipitates (identified from electron microscopy as iron sulfide), and electrodic potentials on bisulfide ion (HS) sensitive silver-silver chloride (Ag-AgCl) electrodes (630 mV) were diagnostic of induced transitions between an aerobic iron sulfide forming conditions and aerobic conditions promoting iron sulfide dissolution. The SIP data showed 10m rad anomalies during iron sulfide mineralization accompanying microbial activity under an anaerobic transition. These anomalies disappeared during iron sulfide dissolution under the subsequent aerobic transition. SIP model parameters based on a Cole-Cole relaxation model of the polarization at the mineral-fluid interface were converted to (1) estimated biomineral surface area to pore volume (Sp), and (2) an equivalent polarizable sphere diameter (d) controlling the relaxation time. The temporal variation in these model parameters is consistent with filling and emptying of pores by iron sulfide biofilms, as the system transitions between anaerobic (pore filling) and aerobic (pore emptying) conditions. The …

A recent independent review led to uncertainty about the technical basis for characterizing the residual amount of tritium in polymer components used in the Savannah River Site Tritium Facilities that are sent for waste disposal. A review of a paper published in the open literature firmly establishes the basis of the currently used characterization, 10 Ci/cc. Information provided in that paper about exposure experiments performed at the DOE Mound Laboratory allows the calculation of the currently used characterization. These experiments involved exposure of high density polyethylene (HD-PE) to initially 1 atm tritium gas. In addition, a review of recent research at the Savannah River Site not only further substantiates this characterization, but also establishes its use for ultra-high molecular weight polyethylene (UHMW-PE), polytetrafluoroethylene (PTFE, a trade name is Teflon{reg_sign}), and Vespel{reg_sign} polyimide. 10 Ci/cc tritium is a representative characterization for any type of polymer components exposed at ambient temperature and at approximately 1 atm. tritium gas.

We have released Version 2 of Milagro, an object-oriented, C++ code that performs radiative transfer using Fleck and Cummings' Implicit Monte Carlo method. Milagro, a part of the Jayenne program, is a stand-alone driver code used as a methods research vehicle and to verify its underlying classes. These underlying classes are used to construct Implicit Monte Carlo packages for external customers. Milagro-2 represents a design overhaul that allows better parallelism and extensibility. New features in Milagro-2 include verified momentum deposition, restart capability, graphics capability, exact energy conservation, and improved load balancing and parallel efficiency. A users' guide also describes how to configure, make, and run Milagro2.

The project entitled 'Scaleable Clean Aluminum Melting Systems' was a Cooperative Research and Development Agreements (CRADAs) between Oak Ridge National Laboratory (ORNL) and Secat Inc. The three-year project was initially funded for the first year and was then canceled due to funding cuts at the DOE headquarters. The limited funds allowed the research team to visit industrial sites and investigate the status of using immersion heaters for aluminum melting applications. Primary concepts were proposed on the design of furnaces using immersion heaters for melting. The proposed project can continue if the funding agency resumes the funds to this research. The objective of this project was to develop and demonstrate integrated, retrofitable technologies for clean melting systems for aluminum in both the Metal Casting and integrated aluminum processing industries. The scope focused on immersion heating coupled with metal circulation systems that provide significant opportunity for energy savings as well as reduction of melt loss in the form of dross. The project aimed at the development and integration of technologies that would enable significant reduction in the energy consumption and environmental impacts of melting aluminum through substitution of immersion heating for the conventional radiant burner methods used in reverberatory furnaces. Specifically, the …

WRN is unique among the five human RecQ DNA helicases by having a functional exonuclease domain (WRN-exo) and being defective in the premature aging and cancer-related disorder Werner syndrome. Here, we characterize WRN-exo crystal structures, biochemical activity and participation in DNA end-joining. Metal ion complex structures, active site mutations and activity assays reveal a two-metal-ion mediated nuclease mechanism. The DNA end-binding Ku70/80 complex specifically stimulates WRN-exo activity, and structure-based mutational inactivation of WRN-exo alters DNA end-joining in human cells. We furthermore establish structural and biochemical similarities of WRN-exo to DnaQ family replicative proofreading exonucleases, with WRN-specific adaptations consistent with dsDNA specificity and functionally important conformational changes. These results indicate WRN-exo is a human DnaQ family member and support analogous proof-reading activities that are stimulated by Ku70/80 with implications for WRN functions in age related pathologies and maintenance of genomic integrity.

Very large multidimensional arrays are commonly used in data intensive scientific computations as well as on-line analytical processingapplications referred to as MOLAP. The storage organization of such arrays on disks is done by partitioning the large global array into fixed size sub-arrays called chunks or tiles that form the units of data transfer between disk and memory. Typical queries involve the retrieval of sub-arrays in a manner that access all chunks that overlap the query results. An important metric of the storage efficiency is the expected number of chunks retrieved over all such queries. The question that immediately arises is"what shapes of array chunks give the minimum expected number of chunks over a query workload?" The problem of optimal chunking was first introduced by Sarawagi and Stonebraker who gave an approximate solution. In this paper we develop exact mathematical models of the problem and provide exact solutions using steepest descent and geometric programming methods. Experimental results, using synthetic and real life workloads, show that our solutions are consistently within than 2.0percent of the true number of chunks retrieved for any number of dimensions. In contrast, the approximate solution of Sarawagi and Stonebraker can deviate considerably from the true result with …

In case of porous fluid-saturated medium the Biot's poroelasticity theory predicts a movement of the pore fluid relative to the skeleton on seismic wave propagation through the medium. This phenomenon opens an opportunity for investigation of the flow properties of the hydrocarbon-saturated reservoirs. It is well known that relative fluid movement becomes negligible at seismic frequencies if porous material is homogeneous and well cemented. In this case the theory predicts an underestimated seismic wave velocity dispersion and attenuation. Based on Biot's theory, Helle et al. (2003) have numerically demonstrated the substantial effects on both velocity and attenuation by heterogeneous permeability and saturation in the rocks. Besides fluid flow effect, the effects of scattering (Gurevich, et al., 1997) play very important role in case of finely layered porous rocks and heterogeneous fluid saturation. We have used both fluid flow and scattering effects to derive a frequency-dependent seismic attribute which is proportional to fluid mobility and applied it for analysis of reservoir permeability.

Proton exchange membrane fuel cells are expected to change the landscape of power generation over the next ten years. For this to be realized one of the most significant challenges to be met for stationary systems is lifetime, where 40,000 hours of operation with less than 10% decay is desired. This project conducted fundamental studies on the durability of membrane electrode assemblies (MEAs) and fuel cell stack systems with the expectation that knowledge gained from this project will be applied toward the design and manufacture of MEAs and stack systems to meet DOE’s 2010 stationary fuel cell stack systems targets. The focus of this project was PEM fuel cell durability – understanding the issues that limit MEA and fuel cell system lifetime, developing mitigation strategies to address the lifetime issues and demonstration of the effectiveness of the mitigation strategies by system testing. To that end, several discoveries were made that contributed to the fundamental understanding of MEA degradation mechanisms. (1) The classically held belief that membrane degradation is solely due to end-group “unzipping” is incorrect; there are other functional groups present in the ionomer that are susceptible to chemical attack. (2) The rate of membrane degradation can be greatly slowed …

The hydride anion H- would not be bound in the absence ofelectron correlation. Electron correlation drives the doublephotoionization process and, thus should impact double photoionizationresults most strongly for H-. We present fully differential crosssections for the three-body breakup of H- by single photon absorption.The absolute triple-differential and single-differential cross sectionswere yielded by ab initio calculations making use of exterior complexscaling within a discrete variable representation partialwave basis.Results calculated at photon energies of 18eV and 30eV are compared withreported cross sections for helium calculated at 20eV above the doubleionization threshold. These comparisons show a clear signature of initialstate correlation that differentiate the He and H- cases.

Small animal SPECT imaging systems have multiple potential applications in biomedical research. Whereas SPECT data are commonly interpreted qualitatively in a clinical setting, the ability to accurately quantify measurements will increase the utility of the SPECT data for laboratory measurements involving small animals. In this work, we assess the effect of photon attenuation, scatter and partial volume errors on the quantitative accuracy of small animal SPECT measurements, first with Monte Carlo simulation and then confirmed with experimental measurements. The simulations modeled the imaging geometry of a commercially available small animal SPECT system. We simulated the imaging of a radioactive source within a cylinder of water, and reconstructed the projection data using iterative reconstruction algorithms. The size of the source and the size of the surrounding cylinder were varied to evaluate the effects of photon attenuation and scatter on quantitative accuracy. We found that photon attenuation can reduce the measured concentration of radioactivity in a volume of interest in the center of a rat-sized cylinder of water by up to 50percent when imaging with iodine-125, and up to 25percent when imaging with technetium-99m. When imaging with iodine-125, the scatter-to-primary ratio can reach up to approximately 30percent, and can cause overestimation of …

Over the past half-century, the Applied Mathematics program in the U.S. Department of Energy's Office of Advanced Scientific Computing Research has made significant, enduring advances in applied mathematics that have been essential enablers of modern computational science. Motivated by the scientific needs of the Department of Energy and its predecessors, advances have been made in mathematical modeling, numerical analysis of differential equations, optimization theory, mesh generation for complex geometries, adaptive algorithms and other important mathematical areas. High-performance mathematical software libraries developed through this program have contributed as much or more to the performance of modern scientific computer codes as the high-performance computers on which these codes run. The combination of these mathematical advances and the resulting software has enabled high-performance computers to be used for scientific discovery in ways that could only be imagined at the program's inception. Our nation, and indeed our world, face great challenges that must be addressed in coming years, and many of these will be addressed through the development of scientific understanding and engineering advances yet to be discovered. The U.S. Department of Energy (DOE) will play an essential role in providing science-based solutions to many of these problems, particularly those that involve the energy, …

The CH-TRU Waste Content Codes (CH-TRUCON) document describes the inventory of the U.S. Department of Energy (DOE) CH-TRU waste within the transportation parameters specified by the Contact-Handled Transuranic Waste Authorized Methods for Payload Control (CH-TRAMPAC). The CH-TRAMPAC defines the allowable payload for the Transuranic Package Transporter-II (TRUPACT-II) and HalfPACT packagings. This document is a catalog of TRUPACT-II and HalfPACT authorized contents and a description of the methods utilized to demonstrate compliance with the CH-TRAMPAC. A summary of currently approved content codes by site is presented in Table 1. The CH-TRAMPAC describes "shipping categories" that are assigned to each payload container. Multiple shipping categories may be assigned to a single content code. A summary of approved content codes and corresponding shipping categories is provided in Table 2, which consists of Tables 2A, 2B, and 2C. Table 2A provides a summary of approved content codes and corresponding shipping categories for the "General Case," which reflects the assumption of a 60-day shipping period as described in the CH-TRAMPAC and Appendix 3.4 of the CH-TRU Payload Appendices. For shipments to be completed within an approximately 1,000-mile radius, a shorter shipping period of 20 days is applicable as described in the CH-TRAMPAC and Appendix 3.5 …

This paper provides a comparative discussion of coupledhydromechanical processes in three different geological formations:crystalline rock, plastic clay, and indurated clay. First, the importantprocesses and associated property characteristics in the three rock typesare discussed. Then, one particular hydromechanical coupling is broughtup for detailed consideration, that of pore pressure changes in nearbyrock during tunnel excavation. Three field experiments in the three rocktypes are presented and their results are discussed. It is shown that themain physical processes are common to all three rock types, but with verydifferent time constants. The different issues raised by these cases arepointed out, and the transferable lessons learned are identified. Suchcross fertilization and simultaneous understanding of coupled processesin three very different rock types help to greatly enhance confidence inthe state of science in this field.

Many tools that target parallel and distributed environments must co-locate a set of daemons with the distributed processes of the target application. However, efficient and portable deployment of these daemons on large scale systems is an unsolved problem. We overcome this gap with LaunchMON, a scalable, robust, portable, secure, and general purpose infrastructure for launching tool daemons. Its API allows tool builders to identify all processes of a target job, launch daemons on the relevant nodes and control daemon interaction. Our results show that Launch-MON scales to very large daemon counts and substantially enhances performance over existing ad hoc mechanisms.

The H-02 Wetland Treatment System (Figure 1) is used to remove heavy metals (e.g., copper and zinc) from the H-Area process and storm water discharge. Routine flow enters an equalization basin by inlets on either the east (Location 1) or west end (Location 2). The west end influent constitutes 75% of the average flow into the basin which has an average residence time of approximately 3 days at low pool (i.e., 120 gal/min. through a volume of 0.5 million gallons). The water then exits via the basin outlet on the east end. Next, the water flows to a splitter box (Location 3) which evenly separates the flow between two wetland cells for a design flow of 60 gal/min. per wetland cell with a residence time in the cell of approximately 2 days. The wetland effluent is then combined (Location 4) and flows through a spillway before reaching the National Pollution Discharge Elimination System (NPDES) measurement point near Road 4. During initial operation, it was observed that the pH of the water leaving the equalization basin was elevated compared to the influent pH. Furthermore, the elevated pH remained through the wetland cells so that there was an average pH of 10 …

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.

The anthrax letters event of 2001 has raised our awareness of the potential importance of non-biological measurements on samples of biological agents used in a terrorism incident. Such measurements include a variety of mass spectral, spectroscopic, and other instrumental techniques that are part of the current armamentarium of the modern materials analysis or analytical chemistry laboratory. They can provide morphological, trace element, isotopic, and other molecular ''fingerprints'' of the agent that may be key pieces of evidence, supplementing that obtained from genetic analysis or other biological properties. The generation and interpretation of such data represents a new domain of forensic science, closely aligned with other areas of ''microbial forensics''. This paper describes some major elements of the R&D agenda that will define this sub-field in the immediate future and provide the foundations for a coherent national capability. Data from chemical and physical analysis of BW materials can be useful to an investigation of a bio-terror event in two ways. First, it can be used to compare evidence samples collected at different locations where such incidents have occurred (e.g. between the powders in the New York and Washington letters in the Amerithrax investigation) or between the attack samples and those seized …

On September 7, 2005, the Commodity Credit Corporation of the U.S. Department of Agriculture (CCC/USDA) presented a Scoping Memo (Argonne 2005) for preliminary consideration by the Kansas Department of Health and Environment (KDHE). This document suggested possible remedial options for the carbon tetrachloride contamination in groundwater at Everest, Kansas. The suggested approaches were discussed by representatives of the KDHE, the CCC/USDA, and Argonne at the KDHE office in Topeka on September 8-9, 2005, along with other technical and logistic issues related to the Everest site. In response to these discussions, the KDHE recommended (KDHE 2005) evaluation of several remedial processes, either alone or in combination, as part of a Corrective Action Study (CAS) for Everest. The primary remedial processes suggested by the KDHE included the following: (1) Hydraulic control by groundwater extraction with aboveground treatment; (2) Air sparging-soil vapor extraction (SVE) in large-diameter boreholes; and (3) Phytoremediation. As a further outcome of the 2005 meeting and as a precursor to the proposed CAS, the CCC/USDA completed the following supplemental investigations at Everest to address several specific technical concerns discussed with the KDHE: (1) Construction of interpretive cross sections at strategic locations selected by the KDHE along the main plume migration …