A broad baseline study of the levels and distributions of trace metals and PCB compounds in sediments has been undertaken. PCB concentrations in surface sediments reflect the source of these contaminates in the region. The highest PCB concentrations as Aroclor 1260 (approximately 10 ng g{sup -1}) were found in sediments near the outflow of the Po river. The lowest concentrations (1.5 ng g{sup -1} dry) were associated with the sediments from the Jabuka Pit in the Middle Adriatic. These values are quite similar to total PCBs (<1.0-17) measured in surface sediments sampled off the coast of Croatia in 1977-78. Thus, based on the limited amount of new data available, it appears that there has been little, if any, decrease in PCB loading in Adriatic sediments over the past 15 years. Downcore profiles of PCBs in sediment cores are also discussed from a pollution history standpoint. Likewise, total mercury in surface sediments was also highest at stations off the Po (403-499 ng g{sup -1} dry) and lowest (67-224 ng g{sup -1}) in the Jabuka Pit. In one core located just south of the Po outflow, total Hg concentrations at all depths were relatively high decreasing gradually from approximately 400 ng g{sup …

The carbon aerogel/carbon paper composites have physical properties similar to those of monolithic carbon aerogels but do not require supercritical extraction during fabrication. The resorcinol-formaldehyde based carbon aerogel phase is intertwined between the fibers of a commercial carbon paper. The resulting composites have variable densities (0.4-0.6 g/cc), high surface areas (300-600 m{sup 2}/g), and controllable pore sizes and pore distribution. The effects of the resorcinol-formaldehyde concentrations (50-70% w/v) and the pyrolysis temperature (600-1050 C) were studied in an attempt to tailor the aerogel microstructure and properties. The composite physical properties and structure were analyzed by transmission electron microscopy and multipoint-BET analyses and related to electrochemical capacitive data in 5M KOH. These thin carbon aerogel/carbon paper composite electrodes are used in experiments with electrochemical double-layer capacitors and capacitive deionization.

Room temperature (RT) pulsed operation of blue nitride based multi-quantum well (MQW) laser diodes grown on c-plane sapphire substrates was achieved. Atmospheric pressure MOCVD was used to grow the active region of the device which consisted of a 10 pair In{sub 0.21}Ga{sub 0.79}N (2.5nm)/In{sub 0.07}Ga{sub 0.93}N (5nm) InGaN MQW. The threshold current density was reduced by a factor of 2 from 10 kA/cm{sup 2} for laser diodes grown on sapphire substrates to 4.8 kA/cm{sub 2} for laser diodes grown on lateral epitaxial overgrowth (LEO) GaN on sapphire. Lasing wavelengths as long as 425nm were obtained. LEDs with emission wavelengths as long as 500nm were obtained by increasing the Indium content. These results show that a reduction in nonradiative recombination from a reduced dislocation density leads to a higher internal quantum efficiency. Further research on GaN based laser diodes is needed to extend the wavelength to 490nm which is required for numerous bio-detection applications. The GaN blue lasers will be used to stimulate fluorescence in special dye molecules when the dyes are attached to specific molecules or microorganisms. Fluorescein is one commonly used dye molecule for chemical and biological warfare agent detection, and its optimal excitation wavelength is 490 nm. InGaN …

A new method for the solution of the unsteady Euler equations has been developed. The method combines staggered grid Lagrangian techniques with structured local adaptive mesh refinement (AMR). This method is a precursor to a more general adaptive arbitrary Lagrangian Eulerian (ALE-AMR) algorithm under development, which will facilitate the solution of problems currently at and beyond the boundary of soluble problems by traditional ALE methods by focusing computational resources where they are required. Many of the core issues involved in the development of the ALE-AMR method hinge upon the integration of AMR with a Lagrange step, which is the focus of the work described here. The novel components of the method are mainly driven by the need to reconcile traditional AMR techniques, which are typically employed on stationary meshes with cell-centered quantities, with the staggered grids and grid motion employed by Lagrangian methods. These new algorithmic components are first developed in one dimension and are then generalized to two dimensions. Solutions of several model problems involving shock hydrodynamics are presented and discussed.

The Project provides for the design, procurement, construction, assembly, installation, and acceptance testing of the National Ignition Facility (NIF), an experimental inertial confinement fusion facility intended to achieve controlled thermonuclear fusion in the laboratory by imploding a small capsule containing a mixture of the hydrogen isotopes, deuterium and tritium. The NIF will be constructed at the Lawrence Livermore National Laboratory (LLNL), Livermore, California as determined by the Record of Decision made on December 19, 1996, as a part of the Stockpile Stewardship and Management Programmatic Environmental Impact Statement (SSM PEIS). Safety: On Saturday April 29, 2000, while preparing the Ringer crane for operation at the NIF site, a mechanical malfunction was observed by the operator. He stopped work and consulted with line management. They agreed with the operator's assessment, and with the Livermore Emergency Duty Officer, implemented a precautionary evacuation of the area around the crane. DOE was notified of the situation. The crane was then placed in a safe condition. A crane maintenance vendor is inspecting the crane and a management team headed by the Beampath Infrastructure System Associate Project Manager is reviewing the documentation, crane history, and repairs to ensure that the crane is fully safe before reuse. …

An international round robin study was conducted on the absorption measurement of laser-quality coatings. Sets of optically coated samples were made by a ''reactive DC magnetron'' sputtering and an ion beam sputtering deposition process. The sample set included a high reflector at 514 nm and a high reflector for the near infrared (1030 to 1318 nm), single layers of silicon dioxide, tantalum pentoxide, and hafnium dioxide. For calibration purposes, a sample metalized with hafnium and an uncoated, superpolished fused silica substrate were also included. The set was sent to laboratory groups for absorptance measurement of these coatings. Whenever possible, each group was to measure a common, central area and another area specifically assigned to the respective group. Specific test protocols were also suggested in regards to the laser exposure time, power density, and surface preparation.

In the transient diffraction NLYF proposal we set forward a program of work to investigate the response of crystals to shock compression in regions of strain rates previously unexplored, in a coordinated experimental, computational, and analytical program. Time resolved x-ray diffraction was used to directly determine the lattice parameters of crystals during shock loading previously on the Nova and Trident laser facilities. Under this proposal we extended this work to exploit the multi-beam direct drive capability of the Omega laser facility to allow more extensive diagnostic access for measuring the lattice parameters both parallel and perpendicular to the shock front. Under the NLUF Program in FY 99, we transitioned the dynamic diffraction experiments to the OMEGA facility. We developed a direct drive target configuration that uses a single beam to direct irradiate the surface of a thin crystal and 4 beams to irradiate a separate metal backlighter foil. Experiments were done with single crystal Si to demonstrate that the target design worked and that simultaneous measurements of compression both parallel and perpendicular to the shock propagation direction could be performed. We obtained simultaneous measurements of the (400) and (040) lattice planes during the period when a shock traveled through the …

In the past several years there have been several large (M{sub w} > 7.0) earthquakes in the eastern Mediterranean region (Gulf of Aqaba, Racha, Adana, etc.), many of which have had aftershock deployments by local seismological organizations. In addition to providing ground truth data (GT << 5 km) that is used in regional location calibration and validation, the waveform data can be used to aid in calibrating regional magnitudes, seismic discriminants, and velocity structure. For small regional events (m{sub b} << 4.5), a stable, accurate magnitude is essential in the development of realistic detection threshold curves, proper magnitude and distance amplitude correction processing, formation of an M{sub s}:m{sub b} discriminant, and accurate yield determination of clandestine nuclear explosions. Our approach provides a stable source spectra from which M{sub w} and m{sub b} can be obtained without regional magnitude biases. Once calibration corrections are obtained for earthquakes, the coda-derived source spectra exhibit strong depth-dependent spectral peaking when the same corrections are applied to explosions at the Nevada Test Site (Mayeda and Walter, 1996), chemical explosions in the recent ''Depth of Burial'' experiment in Kazahkstan (Myers et al., 1999), and the recent nuclear test in India. For events in the western U.S. …

Several types of carbonaceous materials from Superior Graphite Co. were investigated for lithium ion intercalation. These commercially available cokes, graphitized cokes and graphites have a wide range of physical and chemical properties. The coke materials were investigated in propylene carbonate based electrolytes and the graphitic materials were studied in ethylene carbonate/dimethyl solutions to prevent exfoliation. The reversible capacities of disordered cokes are below 230 mAh/g and those for many highly ordered synthetic (artificial) and natural graphites approached 372 mAh/g (LiC{sub 6}). The irreversible capacity losses vary between 15 to as much as 200% of reversible capacities for various types of carbon. Heat treated cokes with the average particle size of 10 microns showed marked improvements in reversible capacity for lithium intercalation. The electrochemical characteristics are correlated with data obtained from scanning electron microscopy (SEM), high resolution transmission electron microscopy (TEM), X-ray diffraction (XRD) and BET surface area analysis. The electrochemical performance, availability, cost and manufacturability of these commercial carbons will be discussed.

Only two intrinsic approaches to increasing the density of energy stored in capacitors are known: (1) Increase the Dielectric Constant while maintaining the breakdown filed; and (2) Increase the breakdown field for a given dielectric constant material. The maximum energy density, E{sub 0} (Joules/cm{sup 3}) that can be stored in the dielectric of a capacitor is given by: E{sub 0} = 1/2 k {var_epsilon}{sub 0} V{sub b}{sup 2} (Joules/cm{sup 3} dielectric). Where k is the relative permittivity (dielectric constant), {var_epsilon}{sub 0} is the permittivity of free space (8.894 x 10{sup -14} F/cm) and V{sub b} the dielectric material breakdown field. In this project we have successfully developed capacitor structures using dielectric materials with 3 < k < 50 that exhibit high breakdown fields. The observed performance of these capacitors as characterized by the energy stored per unit volume of dielectric at V{sub b} are compared on the basis of the breakdown field in Figure 1.

This report summarizes experimentally and numerically determined modal properties for one of the reinforced concrete end walls of the NIF Periscope Support Structure in Laser Bay 1. Two methods were used to determine these modal properties: (1) Computational finite-element analyses (modal extraction process); and (2) Experimental modal analysis based on measured test data. This report also includes experimentally determined modal properties for a prototype LM3/Polarizer line-replaceable unit (LRU) and a prototype PEPC LRU. Two important parameters, used during the design phase, are validated through testing [ref 1]. These parameters are the natural frequencies and modal damping (of the system in question) for the first several global modes of vibration. Experimental modal testing provides these modal values, along with the corresponding mode shapes. Another important parameter, the input excitation (expected during normal operation of the NIF laser system) [ref 1], can be verified by performing a series of ambient vibration measurements in the vicinity of the particular system (or subsystem) of interest. The topic of ambient input excitation will be covered in a separate report. Due to the large mass of the Periscope Pedestal, it is difficult to excite the entire series of Periscope Pedestal Walls all at once. It was …

In July 1993 and June 1995 drifting sediment traps were deployed near the Po outflow, in the coastal zone and in the Jabuka Pit in order to obtain quantitative information on the vertical flux of particulate material and export of organic carbon in the Northern and Middle Adriatic Sea. During these periods and in July 1994, the standing stock of carbon and nitrogen in the water column were also estimated. Carbon and nitrogen concentrations were higher in the north with a mean of 266 {micro}g C l{sup -1} in surface waters as compared to 92 {micro}g C l{sup -1} in Middle Adriatic; maximum concentrations were associated to the less-saline surface-subsurface waters in the north and to the chlorophyll a maximum in the Middle Adriatic. Organic carbon flux was roughly five times higher near the Po than in the more oligotrophic waters of the central region, with overall values (0.8 to 11.5 mg m{sup -2} d{sup -1}) being low compared to the open Northwestern Mediterranean. Comparison with primary production measurements yielded estimates of carbon export (f-ratio) of 4.7 and 3.4% in the Po and Pit stations, respectively, in 1993 and of 1.6 and 3.6% in the central part of the Adriatic …

The microstructures of lithiated synthetic graphite and carbon black were studied by high-resolution transmission electron microscopy (HRTEM) and X-ray diffraction (XRD) analysis. Information about the crystal structure of carbon containing various Li compositions can provide useful insights to our understanding of the Li storage mechanism in carbonaceous materials. Samples with compositions of Li{sub 0.93}C{sub 6} or Li{sub 0.45}C{sub 6} were found to contain both stage-one and stage-two compounds. These observations are consistent with XRD data. The changes in sample microstructure as the results of lithiation and exposure to electron irradiation were observed by TEM and recorded over several minutes in the microscope environment. Selected area electron diffraction patterns indicated that the lithiated samples quickly changed composition to LiC{sub 24}, which appeared to dominate during the brief analysis period. The layer planes in the lattice image of a disordered carbon black after Li insertion are poorly defined, and changes in the microstructure of these lithiated carbons was not readily apparent. Observations on these lithium intercalation compounds as well as the limitation of the experimental procedure will be presented.

A theoretical model for the analysis of ultrasonic guided wave mode excitation of a comb transducer with time delay features was developed. Time delay characteristics are included via a Fourier transform into the frequency domain. The phase velocity spectrum can be used to determine the mode excitation on the phase velocity dispersion curves for a given structure. Experimental and theoretical results demonstrate the tuning of guided wave modes using a time delay comb transducer.

The survivability and performance of the debris shields on the National Ignition Facility (NIF) are a key factor for the successful conduct and affordable operation of the facility. The improvements required over Nova debris shields are described. Estimates of debris shield lifetimes in the presence of target emissions with 4 - 5 J/cm{sup 2} laser fluences (and higher) indicate lifetimes that may contribute unacceptably to operations costs for NIF. We are developing detailed guidance for target and experiment designers for NIF to assist in minimizing the damage to, and therefore the cost of, maintaining NIF debris shields. The guidance limits the target mass that is allowed to become particulate on the debris shields (300 mg). It also limits the amount of material that can become shrapnel for any given shot (10 mg). Finally, it restricts the introduction of non-volatile residue (NVR) that is a threat to the sol-gel coatings on the debris shields to ensure that the chamber loading at any time is less than 1 pg/cm{sup 2}. We review the experimentation on the Nova chamber that included measuring quantities of particulate on debris shields by element and capturing shrapnel pieces in aerogel samples mounted in the chamber. We also …

The Hanford Site 200 Area Effluent Treatment Facility (ETF) processes contaminated liquids derived from Hanford Site facilities. Groundwater monitoring for tritium and other constituents is required by the state-issued permit at 22 wells surrounding the facility. Water level measurements in nearby wells indicate that a small hydraulic mound exists around the SALDS facility as a result of discharges. Evaluation of this condition indicates that the network is currently adequate for tracking potential effects of the SALDS on the groundwater. During FY 2000, average tritium activities in most wells declined from average activities in 1999. The exception was deep well 699-48-77C, where tritium results were at an all-time high (710,000 pCi/L) as a result of the delayed penetration of effluent deeper into the aquifer. Of the 12 constituents with permit enforcement limits, which are monitored in SALDS proximal wells, all were within groundwater limitations during FY 2000. Analyses for conductivity, total dissolved solids, sulfate, chloride, sulfate, dissolved calcium, and dissolved sodium indicate that well 699-48-77A and, to a lesser extent, well 699-48-77D show the effects of dilute effluent entering groundwater, resulting in a depression of concentrations of these constituents below natural background levels. Recommendations for future monitoring include temporarily increasing the …

Post-Remediation Biomonitoring of Pesticides and Other Contaminants in Marine Waters and Sediment Near the United Heckathorn Superfund Site, Richmond, California

The radiation-damaged polystyrene (given the identification name of 'polycube') was fabricated by mixing high-density polystyrene material ("Dylene Fines # 100") with plutonium and uranium oxides. The polycubes were used in the 1960s for criticality studies during processing of spent nuclear fuel. The polycubes have since been stored for almost 40 years at the Hanford Plutonium Finishing Plant (PFP) after failure of two processes to reclaim the plutonium and uranium oxides from the polystyrene matrix. Thermal decomposition products from this highly cross-linked polystyrene matrix were characterized using Gas Chromatograph/Mass Spectroscopy (GC/MS) system coupled to a horizontal furnace. The decomposition studies were performed in air and helium atmospheres at about 773 K. The volatile and semi-volatile organic products for the radiation-damaged polystyrene were different compared to virgin polystyrene. The differences were in the number of organic species generated and their concentrations. In the inert (i.e., helium) atmosphere, the major volatile organic products identified (in order of decreasing concentrations) were styrene, benzene, toluene, ethylbenzene, xylene, nathphalene, propane, .alpha.-methylbenzene, indene and 1,2,3-trimethylbenzene. But in air, the major volatile organic species identified changed slightly. Concentrations of the organic species in the inert atmosphere were significantly higher than those for the air atmosphere processing. Overall, 38 …

Sluicing operations were performed to retrieve high-heat sludge from single-shell tank 241-C-106 and transfer it to double-shell tank 241-AY-102 using the Waste Retrieval Sluicing System. This eliminated the high-heat safety issue for C-106 and demonstrated a technology for retrieval of single-shell tank waste. Both AY-102 and C-106 were monitored during the waste transfer operations, providing a clear picture of general trends in each tank. Specific issues addressed were evaluation of the data for evidence of flammable gas accumulation in AY-102 and thermal performance of AY-102 under the increasing heat load.

In Situ Gaseous Reduction is a technology currently being developed by DOE for the remediation of soil waste sites contaminated with hexavalent chromium. Prior work suggests that a candidate for application of this approach is the 183-DR site at Hanford. However, deep vadose zone drilling is needed to verify the presence of a hexavalent chromium source and to determine the concentration levels and spatial distribution of contamination. This document presents the requirements associated with drilling one to two vadose zone boreholes at the 183-DR site to obtain this information. If hexavalent chromium is determined to be present at levels of at least 10 ppm in the vadose zone in one of the initial boreholes, this hole will be completed for gas injection and six additional gas extraction boreholes will be drilled and completed. This network will be used as a flowcell for performing a gas treatment test at the site.

Representing samll-scale features can be a challenge when one wants to model unsaturated flow in large domains. In this report, the various upscaling techniques are reviewed. The following upscaling methods have been identified from the literature: stochastic methods, renormalization methods, volume averaging and homogenization methods. In addition, a final technique, full resolution numerical modeling, is also discussed.

The purpose of the work described in this report was to identify methods that are currently being used in the Department of Energy (DOE) complex to identify and control hazards/risks in the workplace, evaluate them in terms of their effectiveness in reducing risk to the workers, and to develop a preliminary method that could be used to predict the relative risks to workers performing proposed tasks using some of the current methodology. This report describes some of the performance indicators (i.e., safety metrics) that are currently being used to track relative levels of workplace safety in the DOE complex, how these fit into an Integrated Safety Management (ISM) system, some strengths and weaknesses of using a statistically based set of indicators, and methods to evaluate them. Also discussed are methods used to reduce risk to the workers and some of the techniques that appear to be working in the process of establishing a condition of continuous improvement. The results of these methods will be used in future work involved with the determination of modifying factors for a more complex model. The preliminary method to predict the relative risk level to workers during an extended future time period is based on …

The simulation of the Auxiliary Charcoal Bed (ACB) Vacuum System was performed to evaluate the original vacuum system design, detect and identify design deficiencies, investigate the effects of proposed corrections on system performance, and generally aid in refining the system design before construction and mockup testing. The simulation was performed by using the Advanced Continuous Simulation Language (ACSL). The vacuum system design goals are to provide approximately 20 SCFM of both booster gas and purge gas through the system and maintain a flow of approximately 40 SCFM with a velocity of 50 to 75 f/sec at the entrance to the cyclone separator. The model results showed that the original system design was incapable of meeting the system performance goals. Further simulations showed that the following modifications to the original vacuum system design were required to make the system performance acceptable; (1) Remove valve PCV4. (2) Modify the flow controllers FTC3 and FTC4 from the original flow range of 0-17.6 SCFM (0-500 SLM) to 0-35.3 SCFM (0-1000 SLM). (3) Replace the bellows sealed valves SV-1, SV-3A, SV-3B, SV-4A, and SV-4B with less restrictive ball valves. The simulation results saved considerable time and effort by identifying flaws in the original system design. …

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