This report describes HAVA best practice

December report of the U.S. Congressional Oversight Panel describing their activities and findings regarding the U.S. Treasury's strategy in combating the ongoing financial crisis

We demonstrate the first field trial of optical label-based wavelength switching and packet drop on 476.8km of the National Transparent Optical Network. Subcarrier multiplexed labels control a switch fabric that includes a tunable wavelength converter and arrayed waveguide grating router.

Predictions of airflows around buildings and the associated thermal and dispersion phenomena continue to be challenging because of the presence of extremely heterogeneous surface structures within urban areas. Atmospheric conditions can induce local winds to flow around structures rather than over them. Thus pollutants that are released at or near the ground tend to persist at relatively low levels with only minimal ventilation of the airborne material away from the ground surface. While flow and dispersion phenomena can be studied within wind tunnel settings, recent advances in numerical modeling have enabled computational fluid dynamics (CFD) to evolve into an important tool in the simulation of building scale flows. They are developing numerical models to simulate the flow and dispersion of releases around multi-building complexes. These models will be used to assess the transport and fate of releases of hazardous agents within urban areas and to support emergency response activities. There are already a number of models that have been developed to simulate flow and dispersion around urban settings. A recent collection of these papers can be found in the Proceedings of the International Workshop on CFD for Wind Climate in Cities. Most of the simulation studies presented in the literature …

In our quest for accurate linear scaling first-principles molecular dynamics methods for pseudopotential DFT calculations, we investigate the accuracy of real-space grid approaches, with finite differences and spherical localization regions. We examine how the positions of the localization centers affect the accuracy and the convergence rate of the optimization process. In particular we investigate the accuracy of the atomic forces computation compared to the standard O(N{sup 3}) approach. We show the exponential decay of the error on the energy and forces with the size of the localization regions for a variety of realistic physical systems. We propose a new algorithm to automatically adapt the localization centers during the ground state computation which allows for molecular dynamics simulations with diffusion processes. The combination of algorithms proposed lead to a genuine linear scaling First-Principles Molecular Dynamics method with controlled accuracy. We illustrate our approach with examples of microcanonical molecular dynamics with localized orbitals.

Adoption of hydrogen (H{sub 2}) vehicles has been advocated for decades as an ecological ideal, capable of eliminating petroleum consumption as well as tail-pipe air pollution and carbon dioxide (CO{sub 2}) from automobiles. Storing sufficient hydrogen fuel onboard still remains a great technological challenge, despite recent advances in lightweight automotive materials, hybrid-electric drivetrains and fuel cells enabling 60-100 mpg equivalent H{sub 2}-fueled automobiles. Future onboard hydrogen storage choices will be pivotal, with lasting strategic consequences for the eventual scale, shape, security, investment requirements, and energy intensity of the H{sub 2} refueling infrastructure, in addition to impacts on automotive design, cost, range, performance, and safety. Multiple hydrogen storage approaches have been examined and deployed onboard prototype automobiles since the 1970's. These include storing H{sub 2} as a cryogenic liquid (LH{sub 2}) at temperatures of 20-25 Kelvin, compressing room temperature H{sub 2} gas to pressures as high as 10,000 psi, and reversible chemical absorption storage within powdered metal hydrides (e.g. LaNi{sub 5}H{sub 6}, TiFeH{sub 2}, MgH{sub 2}, NaAlH{sub 4}) which evolve H{sub 2} when warmed. Each of these approaches face well-known fundamental physical limits (thermal endurance, volume, and weight, respectively). This report details preliminary experiments investigating the potential of a new approach …

Although healthy dentin is invariably hydrated in vivo, from a perspective of examining the mechanisms of fracture in dentin, it is interesting to consider the role of water hydration. Furthermore, it is feasible that exposure to certain polar solvents, e.g., those found in clinical adhesives, can induce dehydration. In the present study, in vitro deformation and fracture experiments, the latter involving a resistance-curve (R-curve) approach (i.e., toughness evolution with crack extension), were conducted in order to assess changes in the constitutive and fracture behavior induced by three common solvents - acetone, ethanol and methanol. In addition, nanoindentation-based experiments to evaluate the deformation behavior at the level of individual collagen fibers and ultraviolet Raman spectroscopy to evaluate changes in bonding were performed. The results indicate a reversible effect of chemical dehydration, with increased fracture resistance, strength, and stiffness associated with lower hydrogen bonding ability of the solvent. These results are analyzed both in terms of intrinsic and extrinsic toughening phenomena to further understand the micromechanisms of fracture in dentin and the specific role of water hydration.

Enhancing the proliferation resistance of nuclear energy systems and fuel cycles is an ambitious undertaking. Current systems, dominated by the light water reactor fuel cycle are quite proliferation resistant. However, continued accumulations of plutonium in spent fuel and accumulations of separated plutonium resulting from reprocessing are eroding the proliferation resistance of today's nuclear energy systems. Alternatives to address these issues invariably involve making trade-offs among different proliferation risks and advantages. For example, thorium cycles reduce the quantity and quality of plutonium in spent fuel, but do so at the expense of increased fresh fuel enrichment and/or production of separable U233. Evaluation of these tradeoffs is difficult, as there are serious and significant differences of opinion regarding the relative merits and significance of the various risks of and barriers to proliferation from commercial nuclear power fuel cycles.

Thirty five years ago, while in the neutron cross section group led by Robert Howerton at LLNL, the concept of reconstructing a three dimensional spatial distribution from its projections onto two dimensional planes was tackled by some of us using three now well known methods: simple back projection, Fourier projection theorem methods and iterative least squares algebraic reconstruction. The method of iterative least squares reconstruction was implemented on patient data in the early 1970s using photons from radionuclides detected by the Anger Camera. The method useful for computed tomography was modified to include the attenuation of the photons from an unknown source through an unknown attenuation distribution (a problem thought to be intractable until 1974). These methods along with a multitude of other methods developed by my small group of Ronald Huesman, Grant Gullberg, William Greenberg and Stephen Derenzo were prepared as a library with examples in FORTRAN, RECLBL. Those codes were found useful for computed tomography, geophysical problems and plasma confinement research topics in addition to their use in Nuclear Medicine. The codes were used even in the early days of magnetic resonance imaging when back projection of filtered projection data were used before the incorporation of phase encoding …

The promise of inertial fusion energy driven by heavy ion beams requires the development of accelerators that produce ion currents (approx 100's Amperes/beam) and ion energies ({approx} 1 - 10 GeV) that have not been achieved simultaneously in any existing accelerator. The high currents imply high generalized perveances, large tun depressions, and high space charge potentials of the beam center relative to the beam pipe. Many of the scientific issues associated with ion beams of high perveance and large tune depression have been addressed over the last two decades on scaled experiments at Lawrence Berkeley and Lawrence Livermore National Laboratories, the University of Maryland, and elsewhere. The additional requirement of high space charge potential (or equivalently high line charge density) gives rise to effects (particularly the role of electrons in beam transport) which must be understood before proceeding to a large scale accelerator. The first phase of a new series of experiments in the Heavy Ion Fusion Virtual National Laboratory (HIF VNL), the High Current Experiments (HCX), is now beginning at LBNL. The mission of the HCX is to transport beams with driver line charge density so as to investigate the physics of this regime, including constraints on the maximum …

We describe Merlot, a system for delivery of digital imagery over high speed networks. We describe various use cases, the client/server interaction, and the image and network codecs. We also describe some possible applications using Merlot and future work.

Paleorecords from Minnesota and adjacent areas have often been used to evaluate large-scale climatic processes in the mid-continent of North America. However, most of these records are compromised by chronological flaws, making problematic any comparisons with climatic interpretations based on other records (e.g., GISP2 in Greenland). We report here a high-resolution pollen record with a secure chronology constrained by 26 {sup 14}C dates on terrestrial macrofossils from Steel Lake, central Minnesota. About 11,200 years ago (calibrated yr BP) the late-glacial Picea forest near Steel Lake was succeeded abruptly by Pinus banksiana and/or resinosa. The Pinus forest began to open 9.4 ka cal BP with the expansion of prairie taxa, and a pine parkland or savanna prevailed until about 8 ka cal BP, when Quercus replaced Pinus to become the dominant tree in the prairie areas for 4500 years. The close chronological control permits the correlation of key vegetational changes with those at other reliably dated sites in the eastern Dakotas and in Minnesota, suggesting that the abrupt decline of the spruce forest was time-transgressive from southwest to northeast during 2000 years, and that the development of prairie was time-transgressive in the same direction over 2600 years. Correlation of key pollen …

This project aimed to establish feasibility of using experimental techniques based on direct measurements of interaction forces on the single molecule scale to characterize equilibrium interaction potentials between individual biological molecules. Such capability will impact several research areas, ranging from rapid interaction screening capabilities to providing verifiable inputs for computational models. It should be one of the enabling technologies for modern proteomics research. This study used a combination of Monte-Carlo simulations, theoretical considerations, and direct experimental measurements to investigate two model systems that represented typical experimental situations: force-induced melting of DNA rigidly attached to the tip, and force-induced unbinding of a protein-antibody pair connected to flexible tethers. Our results establish that for both systems researchers can use force spectroscopy measurements to extract reliable information about equilibrium interaction potentials. However, the approaches necessary to extract these potentials in each case--Jarzynski reconstruction and Dynamic Force Spectroscopy--are very different. We also show how the thermodynamics and kinetics of unbinding process dictates the choice between in each case.

A novel handheld time-domain array GPR antipersonnel mine detection system using an offset paraboloidal reflector antenna is described. The reflector collimates rays from an ultra-wideband transmitting feed, directing the microwave impulse forward, in front of the antenna structure. As such, much of the ground reflected wave is directed further forward, away from the operator, the reflector, and the receiving antennas, and thereby reducing the major source of clutter. The wave transmitted into the ground that interacts with the target, generating significant backscatter returning toward the receiving antennas. These receiving antennas are configured in a 2 by 2 array to provide spatial focusing in both the along- and cross-track directions. This system has been built and tested at both Lawrence Livermore National Laboratory, and GeoCenters, Inc. In both cases, custom-built wideband antenna elements generate narrow pulse shapes, which allow for resolving small non-metallic targets buried at shallow depths. The LLNL's Micro-Power Impulse Radar (MIR) operates in the 1.5 to 5 GHz range a very narrow pulse shape. The Geo-Centers wideband TEMR antenna elements have higher power, though lower frequency range (850 to 1700 MHz), and generate less residual ringing in the time signal. Preliminary measured data from both systems indicate that …

Bulk damage sites in frequency conversion crystals scatter and/or absorb laser light leading to interference and downstream intensification .We find that laser induced bulk damage sites in DKDP exhibit a 'shell' of structurally and/or chemically modified material surrounding a central core as indicated by SEM and optical micrographs and micro Raman spectral maps. We hypothesize that the modified material has been shock wave densified and estimate the amount of densification and its effect on scattering. A simple model indicates that densification of several percent is likely and that the scattering cross section may be larger than the geometric area of the inner core by an order of magnitude.

Millions of people suffering from diseases such as retinitis pigmentosa and macular degeneration are legally blind due to the loss of photoreceptor function. Fortunately a large percentage of the neural cells connected to the photoreceptors remain viable, and electrical stimulation of these cells has been shown to result in visual perception. These findings have generated worldwide efforts to develop a retinal prosthesis device, with the hope of restoring vision. Advances in microfabrication, integrated circuits, and wireless technologies provide the means to reach this challenging goal. This dissertation describes the development of innovative silicone-based microfabrication techniques for producing an implantable microelectrode array. The microelectrode array is a component of an epiretinal prosthesis being developed by a multi-laboratory consortium. This array will serve as the interface between an electronic imaging system and the human eye, directly stimulating retinal neurons via thin film conducting traces. Because the array is intended as a long-term implant, vital biological and physical design requirements must be met. A retinal implant poses difficult engineering challenges due to the size of the intraocular cavity and the delicate retina. Not only does it have to be biocompatible in terms of cytotoxicity and degradation, but it also has to be structurally …

Metal matrix composites (MMCs) containing matrices with nanometer grain sizes have been produced from pure aluminum nano-powders (particle sizes 50-200 nm) with SiC reinforcement (particle sizes 3-10 {micro}m). The pure Al nano-powders were produced using an exploding wire technique. Dynamic loading using a magnetic impulse technique has been used to compact the MMC to high density. The dynamic compaction process results in excellent wetting of the SiC particles by the nanocrystalline Al powders, and the retention of a nano-crystalline grain size in the MMC. Microstructural analysis of the resulting MMC showed a highly uniform distribution of Sic particles with no visible defects or pores and the absence of deleterious phases (such as Al{sub 4}C{sub 3}) at the interfaces between the aluminum nano-grains and the SiC particles. The microstructures produced and the evolution of microstructure during dynamic compaction has also been studied using TEM and found to progress in three stages. These three stages are described.

Double-shell ignition is complementary to the baseline approach by virtue of not requiring: (1) cryogenic preparation and fielding, (2) high-contrast pulse-shaping for shock-timing, and (3) demanding x-ray flux symmetry control. The use of simpler low-contrast pulse-shaping potentially allows more benign hohlraum conditions by reducing the risk of laser backscatter. In addition, the associated higher laser fluence threshold for optics damage initiation allows the possibility of more routine high-fluence shots with 2{omega} on the NIF. Based on LDRD-sponsored research in FY01-03 on NIF double-shell ignition target designs, the feasibility of this approach was advanced through both a highly successful implosion campaign on the Omega laser facility and a variety of design improvements for mitigating instability. The double-shell implosion campaign on Omega achieved the important milestone of repeatably demonstrating dominant primary (2.45 MeV) neutron production from the mix-susceptible compressional phase of a double-shell implosion, using fall-line design optimization and exacting fabrication standards. Showing effective control of fuel-pusher mix during final compression is an essential element for achieving ignition. In our studies to control mix by reducing hydrodynamic instability a new pathway for destructive Rayleigh-Taylor growth on the outer surface of the inner shell at ignition scales was identified. However, highly resolved multi-mode …

In response to concerns expressed by the California Legislature and the citizenry of the State of California, the State Water Resources Control Board (SWRCB), implemented a program to assess groundwater quality, and provide a predictive capability for identifying areas that are vulnerable to contamination. The program was initiated in response to concern over public supply well closures due to contamination by chemicals such as MtBE from gasoline, and solvents from industrial operations. As a result of this increased awareness regarding groundwater quality, the Supplemental Report of the 1999 Budget Act mandated the SWRCB to develop a comprehensive ambient groundwater-monitoring plan, and led to the initiation of the Ambient Groundwater Monitoring and Assessment (GAMA) Program. The primary objective of the GAMA Program is to assess the water quality and to predict the relative susceptibility to contamination of groundwater resources throughout the state of California. Under the GAMA program, scientists from Lawrence Livermore National Laboratory (LLNL) collaborate with the SWRCB, the U.S. Geological Survey, the California Department of Health Services (DHS), and the California Department of Water Resources (DWR) to implement the groundwater assessment program in cooperation with local water purveyors. In 2001 and 2002, LLNL carried out this vulnerability study in …

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The reflectance stability of multilayer coatings for extreme ultraviolet lithography (EUVL) in a commercial tool environment is of uttermost importance to ensure continuous exposures with minimum maintenance cost. We have made substantial progress in designing the protective capping layer coatings, understanding their performance and estimating their lifetimes based on accelerated electron beam and EUV exposure studies. Our current capping layer coatings have about 40 times longer lifetimes than Si-capped multilayer optics. Nevertheless, the lifetime of current Ru-capped multilayers is too short to satisfy commercial tool requirements and further improvements are essential.

This revision of PNNL-13895 is an updated version of the original document. The changes in this document include the addition of Kd data for iodide and uranium that became available during fiscal year 2003. Supplementary data are also included regarding the sediment and solution characteristic used in the studies. The original document compiles in a single source the Kd values measured with Hanford sediment for radionuclides and toxic compounds that have the greatest potential for driving risk to human health and safety in the vadose zone and groundwater at the Hanford Site.

This document presents the vision for Brookhaven National Laboratory (BNL) for the next five years, and a roadmap for implementing that vision. Brookhaven is a multidisciplinary science-based laboratory operated for the U.S. Department of Energy (DOE), supported primarily by programs sponsored by the DOE's Office of Science. As the third-largest funding agency for science in the U.S., one of the DOE's goals is ''to advance basic research and the instruments of science that are the foundations for DOE's applied missions, a base for U.S. technology innovation, and a source of remarkable insights into our physical and biological world, and the nature of matter and energy'' (DOE Office of Science Strategic Plan, 2000 http://www.osti.gov/portfolio/science.htm). BNL shapes its vision according to this plan.

This paper describes simulation and experimental results for a 1400A, {+-} 900V peak rated, switch mode power supply for SNS Injection Kicker Magnets. For each magnet (13 m{Omega}, 160{micro}H), the power supply must supply controlled pulses at 60 Hz repetition rate. The pulse current must rise from zero to maximum in less than 1 millisec in a controlled manner, flat top for up to 2 millisec, and should fall in a controlled manner to less than 4A within 500{micro}s. The low current performance during fall time is the biggest challenge in this power supply. The simulation results show that to meet the controlled fall of the current and the current ripple requirements, voltage loop bandwidth of at least 10 kHz and switching frequency of at least 100 kHz are required. To achieve high power high frequency switching with IGBT switches, a series connected topology with three phase shifted (O{sup o}, 60{sup o} & 120{sup o}) converters each with 40 kHz switching frequency (IGBT at 20kHz), has been achieved. In this paper, the circuit topology, relevant system specifications and experimental results that meet the requirements of the power supply are described in detail. A unique six pulse SCR rectifier circuit with …