Polychlorinated biphenyls (PCBs) are a major environmental concern due to their ubiquity and tendency to bio-accumulate. as well as their persistence and toxicity. As the cleanup of waste and contaminated soil progresses at U.S. Department of Energy (DOE) sites, the costs for accurate PCB data are increasing. PCBs are actually a broad name for a group of 209 individual compounds known as congeners. PCBs were originally produced in the United States as specific mixtures of congeners known as Aroclors'. PCBs can be analyzed and quantified either as Aroclor mixtures or as individual congeners. Aroclor analysis, which is the more common analytical method applied to PCBs. has been in use for decades, and in general, most cleanup regulations are based on total PCB concentrations using Aroclor analyses. Congener analysis is relatively new to environmental cleanup and restoration due to both technical issues and associated cost. The benefits of congener analysis are that it allows a more direct analysis of the risk of the PCBs. The World Health Organization (WHO) has identified twelve specific congeners as dioxin-like with toxicity ranging from 0.00003 to 0.1 times the standard 2,3,7.8-Tetrachlorodibenzo-p-dioxin (2.3.7.8-TCDD) toxicity. This paper defines Aroclors and congeners and compares the current application and …

Our previous atomic force microscopy (AFM) studies successfully visualized native Bacillus atrophaeus spore coat ultrastructure and surface morphology. We have shown that the outer spore coat surface is formed by a crystalline array of {approx}11 nm thick rodlets, having a periodicity of {approx}8 nm. We present here further AFM ultrastructural investigations of air-dried and fully hydrated spore surface architecture. In the rodlet layer, planar and point defects, as well as domain boundaries, similar to those described for inorganic and macromolecular crystals, were identified. For several Bacillus species, rodlet structure assembly and architectural variation appear to be a consequence of species-specific nucleation and crystallization mechanisms that regulate the formation of the outer spore coat. We propose a unifying mechanism for nucleation and self-assembly of this crystalline layer on the outer spore coat surface.

The conversion efficiency of ultra short-pulse laser radiation to K-{alpha} x-rays has been measured for various chlorine-containing targets to be used as x-ray scattering probes of dense plasmas. The spectral and temporal properties of these sources will allow spectrally-resolved x-ray scattering probing with picosecond temporal resolution required for measuring the plasma conditions in inertial confinement fusion experiments. Simulations of x-ray scattering spectra from these plasmas show that fuel capsule density, capsule ablator density, and shock timing information may be inferred.

Unalloyed molybdenum and Oxide Dispersion Strengthened (ODS) molybdenum were irradiated at 300 C and 600 C in the high flux isotope reactor (HFIR) to neutron fluences of 0.2, 2.1, and 24.3 x 10{sup 24} n/m{sup 2} (E > 0.1 MeV), producing damage levels of 0.01, 0.1 and 1.3 Mo-dpa. Hardness measurements, electrical resistivity measurements, tensile testing, and Transmission Electron Microscopy (TEM) were used to assess the defect structure. Irradiation hardening was evident even at a damage level of 0.01 dpa resulting in a significant increase in yield stress, decrease in ductility, and elevation of the Ductile-to-Brittle Transition Temperature (DBTT). The observed size and number density of voids and loops as well as the measured irradiation hardening and electrical resistivity were found to increase sub-linearly with fluence over the range of exposure investigated. This supports the idea that the formation of the extended defects that produce irradiation hardening in molybdenum are the result of a nucleation and growth process rather than the formation of sessile defects directly from the displacement damage cascades. The formation of sessile defect clusters in the displacement cascade would be expected to result in a linear fluence dependence for the number density of defects followed by saturation …

The {alpha} to {beta} transition in pure Ti occurs mainly by a 'martensitic type' phase transformation. In such transformations, growth rates and interface velocities tend to be very large, on the order of 10{sup 3} m/s, making it difficult to observe the transformation experimentally. With thin films, it becomes even more difficult to observe, since the large surface augments the nucleation and transformation rates to levels that require nanosecond temporal resolution for experimental observations. The elucidation of the transformational mechanisms in these materials yearns for an apparatus that has both high spatial and temporal resolution. We have constructed such an instrument at LLNL (the dynamical transmission electron microscope or DTEM) that combines pulsed lasers systems and optical pump-probe techniques with a conventional TEM. We have used the DTEM to observe the transient events of the {alpha}-{beta} transformation in nanocrystalline Ti films via single shot diffraction patterns with 1.5 ns resolution. With pulsed, nanosecond laser irradiation (pump laser), the films were heated at an extreme rate of 10{sup 10} K/s. was observed At 500 ns after the initial pump laser hit, the HCP, alpha phase was almost completely transformed to the BCC, beta phase. Post-mortem investigations of the laser treated films …

Laboratory corrosion tests were conducted to investigate the corrosivity of moist plutonium oxide/chloride (PuO{sub 2}/Cl-) salt mixtures on 304L and 316L stainless steel coupons. The tests exposed flat coupons for pitting evaluation and 'teardrop' stressed coupons for stress corrosion cracking (SCC) evaluation at room temperature to various mixtures of PuO{sub 2} and chloride-bearing salts for periods up to 500 days. The two flat coupons were placed so that the solid oxide/salt mixture contacted about one half of the coupon surface. One teardrop coupon was placed in contact with solid mixture; the second teardrop was in contact with the headspace gas only. The mixtures were loaded with nominally 0.5 wt % water under a helium atmosphere. Observations of corrosion ranged from superficial staining to pitting and SCC. The extent of corrosion depended on the total salt concentration and on the composition of the salt. The most significant corrosion was found in coupons that were exposed to 98 wt % PuO{sub 2}, 2 wt % chloride salt mixtures that contained calcium chloride. SCC was observed in two 304L stainless steel teardrop coupons exposed in solid contact to a mixture of 98 wt % PuO{sub 2}, 0.9 wt % NaCl, 0.9 wt % …

The simplest extension of the supersymmetric standard model--the addition of one singlet superfield--can have a profound impact on the Higgs and its decays. We perform a general operator analysis of this scenario, focusing on the phenomenologically distinct scenarios that can arise, and not restricting the scope to the narrow framework of the NMSSM. We reexamine decays to four b quarks and four {tau}'s, finding that they are still generally viable, but at the edge of LEP limits. We find a broad set of Higgs decay modes, some new, including those with four gluon final states, as well as more general six and eight parton final states. We find the phenomenology of these scenarios is dramatically impacted by operators typically ignored, specifically those arising from D-terms in the hidden sector, and those arising from weak-scale colored fields. In addition to sensitivity of m{sub z}, there are potential tunings of other aspects of the spectrum. In spite of this, these models can be very natural, with light stops and a Higgs as light as 82 GeV. These scenarios motivate further analyses of LEP data as well as studies of the detection capabilities of future colliders to the new decay channels presented.

Making use of the measurement of the $B\to K^*\gamma$ branching ratio together with the relations following from the limit of high recoil energy, we obtain stringent constraints on the values of the form-factors entering in heavy-to-light $B\to V\ell\ell'$ processes such as $B\to K^*\ell^+\ell^-$, $B\to K^*\nu \bar\nu$ and $B\to \rho\ell\nu$ decays. We show that the symmetry predictions, when combined with the experimental information on radiative decays, specify a severely restricted set of values for the vector and axial-vector form-factors evaluated at zero momentum transfer, $q^2=0$. These constraints can be used to test model calculations and to improve our understanding of the $q^2$-dependence of semileptonic form-factors. We stress that the constraints remain stringent even when corrections are taken into account.

Methane mixing ratios measured at a tall-tower are compared to model predictions to estimate surface emissions of CH{sub 4} in Central California for October-December 2007 using an inverse technique. Predicted CH{sub 4} mixing ratios are calculated based on spatially resolved a priori CH{sub 4} emissions and simulated atmospheric trajectories. The atmospheric trajectories, along with surface footprints, are computed using the Weather Research and Forecast (WRF) coupled to the Stochastic Time-Inverted Lagrangian Transport (STILT) model. An uncertainty analysis is performed to provide quantitative uncertainties in estimated CH{sub 4} emissions. Three inverse model estimates of CH{sub 4} emissions are reported. First, linear regressions of modeled and measured CH{sub 4} mixing ratios obtain slopes of 0.73 {+-} 0.11 and 1.09 {+-} 0.14 using California specific and Edgar 3.2 emission maps respectively, suggesting that actual CH{sub 4} emissions were about 37 {+-} 21% higher than California specific inventory estimates. Second, a Bayesian 'source' analysis suggests that livestock emissions are 63 {+-} 22% higher than the a priori estimates. Third, a Bayesian 'region' analysis is carried out for CH{sub 4} emissions from 13 sub-regions, which shows that inventory CH{sub 4} emissions from the Central Valley are underestimated and uncertainties in CH{sub 4} emissions are reduced …

Experimental discoveries followed by theoretical interpretations that pave the way of further advances by experimentalists is a developing pattern in modern surface chemistry and catalysis. The revolution of modern surface science started with the development of surface-sensitive techniques such as LEED, XPS, AES, ISS and SIMS, in which the close collaboration between experimentalists and theorists led to the quantitative determination of surface structure and composition. The experimental discovery of the chemical activity of surface defects and the trends in the reactivity of transitional metals followed by the explanations from the theoretical studies led to the molecular level understanding of active sites in catalysis. The molecular level knowledge, in turn, provided a guide for experiments to search for new generation of catalysts. These and many other examples of successes in experiment-and-theory-combined studies demonstrate the importance of the collaboration between experimentalists and theorists in the development of modern surface science.

Managing subsurface damage during the shaping process and removing subsurface damage during the polishing process is essential in the production of low damage density optical components, such as those required for use on high peak power lasers. Removal of subsurface damage, during the polishing process, requires polishing to a depth which is greater than the depth of the residual cracks present following the shaping process. To successfully manage, and ultimately remove subsurface damage, understanding the distribution and character of fractures in the subsurface region introduced during fabrication process is important. We have characterized the depth and morphology of subsurface fractures present following fixed abrasive and loose abrasive grinding processes. At shallow depths lateral cracks and an overlapping series of trailing indentation fractures were found to be present. At greater depths, subsurface damage consists of a series of trailing indentation fractures. The area density of trailing fractures changes as a function of depth, however the length and shape of individual cracks remain nearly constant for a given grinding process. We have developed and applied a model to interpret the depth and crack length distributions of subsurface surface damage in terms of key variables including abrasive size and load.

A design study was undertaken to develop a ''first cut'' integrated mechanical design concept of the final focusing region for a conceptual IFE power plant that considers the major issues which must be addressed in an integrated driver and chamber system. The conceptual design in this study requires a total of 120 beamlines located in two conical arrays attached on the sides of the target chamber 180 degrees apart. Each beamline consists of four large-aperture superconducting quadrupole magnets and a dipole magnet. The major interface issues include radiation shielding and thermal insulation of the superconducting magnets; reaction of electromagnetic loads between the quadrupoles; alignment of the magnets; isolation of the vacuum regions in the target chamber from the beamline, and assembly and maintenance.

Geometry processing algorithms have traditionally assumed that the input data is entirely in main memory and available for random access. This assumption does not scale to large data sets, as exhausting the physical memory typically leads to IO-inefficient thrashing. Recent works advocate processing geometry in a 'streaming' manner, where computation and output begin as soon as possible. Streaming is suitable for tasks that require only local neighbor information and batch process an entire data set. We describe a streaming compression scheme for tetrahedral volume meshes that encodes vertices and tetrahedra in the order they are written. To keep the memory footprint low, the compressor is informed when vertices are referenced for the last time (i.e. are finalized). The compression achieved depends on how coherent the input order is and how many tetrahedra are buffered for local reordering. For reasonably coherent orderings and a buffer of 10,000 tetrahedra, we achieve compression rates that are only 25 to 40 percent above the state-of-the-art, while requiring drastically less memory resources and less than half the processing time.

Fabrication of compositionally graded structures for use as light-gas gun impactors has been demonstrated using a tape casting technique. Mixtures of metal powders in the Mg-Cu system were cast into a series of tapes with uniform compositions ranging from 100% Mg to 100% Cu. The individual compositions were fabricated into monolithic pellets for characterization by laminating multiple layers together, thermally removing the organics, and hot-pressing to near-full density. The pellets were characterized by optical and scanning electron microscopy, X-ray diffraction, and measurement of density and sound wave velocity. The density and acoustic impedance were observed to vary monotonically (and nearly linearly) with composition. Graded structures were fabricated by stacking layers of different compositions in a sequence calculated to yield a desired acoustic impedance profile. The measured physical properties of the graded structures compare favorably with those predicted from the monolithic-pellet characteristics. Fabrication of graded impactors by this technique is of significant interest for providing improved control of the pressure profile in gas gun experiments.

The 232-Z Plutonium Incinerator Facility was a small, highly alpha-contaminated, building situated between three active buildings located in an operating nuclear complex. Approximately 500 personnel worked within 250 meters (800 ft) of the structure and expectations were that the project would neither impact plant operations nor result in any restrictions when demolition was complete. Precision demolition and tight controls best describe the project. The team used standard open-air demolition techniques to take the facility to slab-on-grade. Several techniques were key to controlling contamination and confining it to the demolition area: spraying fixatives before demolition began; using misting systems, frequently applying fixatives, and using a methodical demolition sequence and debris load-out process. Detailed air modeling was done before demolition to determine necessary facility source-term levels, establish radiological boundaries, and confirm the adequacy of the proposed demolition approach. By only removing the major source term in equipment, HEPA filters, gloveboxes, and the like, and leaving fixed contamination on the walls, ceilings and floors, the project showed considerable savings and reduced worker hazards and exposure. The ability to perform this demolition safely and without the spread of contamination provides confidence that similar operations can be performed successfully. By removing the major source terms, …

The Courant-Snyder parameterization of one-dimensional linear betatron motion is generalized to two-dimensional coupled linear motion. To represent the 4 x 4 symplectic transfer matrix the following ten parameters were chosen: four beta-functions, four alpha-functions and two betatron phase advances which have a meaning similar to the Courant-Snyder parameterization. Such a parameterization works equally well for weak and strong coupling and can be useful for analysis of coupled betatron motion in circular accelerators as well as in transfer lines. Similarly, the transfer matrix, the bilinear form describing the phase space ellipsoid and the second order moments are related to the eigen-vectors. Corresponding equations can be useful in interpreting tracking results and experimental data.

From a controls viewpoint, contemporary high energy physics collider detectors are comparable in complexity to small to medium size accelerators: however, their controls requirements often differ significantly. D0, one of two collider experiments at Fermilab, has recently started a second, extended running period that will continue for the next five years. EPICS [1], an integrated set of software building blocks for implementing a distributed control system, has been adapted to satisfy the slow controls needs of the D0 detector by (1) extending the support for new device types and an additional field bus, (2) by the addition of a global event reporting system that augments the existing EPICS alarm support, and (3) by the addition of a centralized database with supporting tools for defining the configuration of the control system. This paper discusses the control architecture of the current D0 experiment, how the EPICS system was extended to meet the control requirements of a large, high-energy physics detector, and how a formal control system contributes to the management of detector operations.

A complement of 266 users, staff, and vendors descended upon the Ernest Orlando Lawrence Berkeley National Laboratory (Berkeley Lab) from Monday through Wednesday, October 16-18, 2000 for the thirteenth edition of the annual Advanced Light Source (ALS) users meeting. In a departure from previous practice, the meeting featured an increased emphasis on workshops with the result that the proceedings were equally divided between oral and poster presentations and the workshops. After the traditional welcomes and facility updates on the first morning, science dominated the first day and a half comprising the formal meeting with a session of highlights from young researchers, three sessions of scientific highlights from the ALS and elsewhere, and a poster session that included a student poster competition. A set of seven workshops covering research areas of current or growing interest at the ALS rounded out the final day and a half of the meeting.

For the next generation of large accelerators, the civil engineering of accelerator tunnels and associated underground enclosures will be a major component of the technical challenge of building such machines. Because of the large scale involved, the engineering will be required to be as cost-effective as possible, and issues such as ground motion and artificial sources of vibration in the environment will need to be carefully considered. installation and alignment of the machine components will be tasks of unprecedented scope, and will require unprecedented precision. Examine in detail the most important and most difficult aspects of these challenges, both from the point of view of performance and cost-effectiveness. In particular, identify what the site requirements are for the different machines under discussion (JLC, NLC, TESLA, VLHC, Muon source), and describe how tunneling methods are affected by them. Identify, for the different types of accelerators, the different length scales that are involved in defining the alignment tolerances, and what are the tolerances over that length scale. Specify the R and D efforts needed to define the scope of the most critical challenges, and prioritize the efforts, in terms of the potential to provide maximal performance and/or cost-effectiveness. Establish a technology-limited time …

We have measured the production of h{nu} {ge} 4.5 keV x-rays from low-density Ti-doped aerogel targets at the OMEGA laser facility (University of Rochester). The doped-foam density was {approx} 3 mg/cc. Forty beams of the OMEGA laser ({lambda}{sub L} = 0.351 {micro}m) illuminated the two cylindrical faces of the target with a total power that ranged from 7 to 14 TW. The laser interaction fully ionizes the target (n{sub e}/n{sub crit} {ge} 0.1), and allows the laser-bleaching wave to excite, supersonically, the high-Z emitter ions in the sample. Ti K-shell x-ray emission was spectrally resolved with a two-channel crystal spectrometer and also with a set of filtered aluminum x-ray diodes, both instruments provide absolute measurement of the multi-keV x-ray emission. Back-scattered laser energy is observed to be minimal. We find between 40 - 260 J of output with 4.67 {le} h{nu} {le} 5.0 keV.

This paper describes a technique for applying the transition probability geostatistics method for stochastic simulation to a MODFLOW model. Transition probability geostatistics has several advantages over traditional indicator kriging methods including a simpler and more intuitive framework for interpreting geologic relationships and the ability to simulate juxtapositional tendencies such as fining upwards sequences. The indicator arrays generated by the transition probability simulation are converted to layer elevation and thickness arrays for use with the new Hydrogeologic Unit Flow (HUF) package in MODFLOW 2000. This makes it possible to preserve complex heterogeneity while using reasonably sized grids. An application of the technique involving probabilistic capture zone delineation for the Aberjona Aquifer in Woburn, Ma. is included.

Double shell targets have been built by Lawrence Livermore National Laboratory (LLNL) for inertial confinement fusion (ICF) experiments on the Omega laser at the University of Rochester and as a prelude to similar experiments on NIF. Of particular interest to ICF studies are high-precision double shell implosion targets for demonstrating thermonuclear ignition without the need for cryogenic preparation. Because the ignition tolerance to interface instabilities is rather low, the manufacturing requirements for smooth surface finishes and shell concentricity are particularly strict. This paper describes a deterministic approach to manufacturing and controlling error sources in each component. Included is the design philosophy of why certain manufacturing techniques were chosen to best reduce the errors within the target. The manufacturing plan developed for this effort created a deterministic process that, once proven, is repeatable. By taking this rigorous approach to controlling all error sources during the manufacture of each component and during assembly, we have achieved the overall 5 {micro}m dimensional requirement with sub-micron surface flaws. Strengths and weaknesses of the manufacturing process will be discussed.

To significantly improve the simulation of climate by general circulation models (GCMs), systematic errors in representations of relevant processes must first be identified, and then reduced. This endeavor demands, in particular, that the GCM parameterizations of unresolved processes should be tested over a wide range of time scales, not just in climate simulations. Thus, a numerical weather prediction (NWP) methodology for evaluating model parameterizations and gaining insights into their behavior may prove useful, provied that suitable adaptations are made for implementation in climate GCMs. This method entails the generation of short-range weather forecasts by realistically initialized climate GCM, and the application of six-hourly NWP analyses and observations of parameterized variables to evaluate these forecasts. The behavior of the parameterizations in such a weather-forecasting framework can provide insights on how these schemes might be improved, and modified parameterizations then can be similarly tested. In order to further this method for evaluating and analyzing parameterizations in climate GCMs, the USDOE is funding a joint venture of its Climate Change Prediction Program (CCPP) and Atmospheric Radiation Measurement (ARM) Program: the CCPP-ARM Parameterization Testbed (CAPT). This article elaborates the scientific rationale for CAPT, discusses technical aspects of its methodology, and presents examples of its …

The use of sprayed flammable fluids as solvents in dissolution and cleaning processes demand detailed understanding of ignition and fire hazards associated with these applications. When it is not feasible to inert the atmosphere in which the spraying process takes place, then elimination of all possible ignition sources must be done. If operators are involved in the process, the potential for human static build-up and ultimate discharge is finite, and it is nearly impossible to eliminate. The specific application discussed in this paper involved the use of heated Dimethyl Sulfoxide (DMSO) to dissolve high explosives (HE). Search for properties of DMSO yielded data on flammability limits and flash point, but there was no published information pertaining to the minimum energy for electrical arc ignition. Due to the sensitivity of this procedure, The Hazards Control Department of Lawrence Livermore National Laboratory (LLNL) was tasked to determine the minimum ignition energy of DMSO aerosol and vapor an experimental investigation was thus initiated. Because there were no electrical sources in spray chamber, Human Electro-Static Discharge (HESD) was the only potential ignition source. Consequently, the electrostatic generators required for this investigation were designed to produce electrostatic arcs with the defined voltage and current pulse …