The fate of six volatile organic compounds (VOC) in a 150-meter deep vadose zone was examined in support of a RCRA Corrective Measures Study of the Chemical Waste Landfill at Sandia National Laboratories, Albuquerque, New Mexico. The study focused on the modeling of potential future transport of the VOCs to exposure media upon the completion of two separate voluntary corrective measures--soil vapor extraction and landfill excavation--designed to significantly reduce contaminant levels in subsurface soils. modeling was performed with R-UNSAT, a finite-difference simulator that was developed by the U.S. Geological Survey. R-UNSAT facilitated a relatively unique and comprehensive assessment of vapor transport because it (1) simulated the simultaneous movement of all six VOCs, taking into account each constituent's diffusion coefficient as affected by its mole fraction within a mixture of chemicals, and (2) permitted simultaneous assessment of risk to human health via volatilization (air) and drinking water (groundwater) pathways. Modeling results suggested that monitored natural attenuation would represent a viable remedial alternative at the landfill after both voluntary corrective measures were completed.

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The positions of Ge atoms intermixed in the Si(100) surface at very low concentration are identified using empty-state imaging in scanning tunneling microscopy. A measurable degree of place exchange occurs at temperatures as low as 330 K. Contrary to earlier conclusions, good differentiation between Si atoms and Ge atoms can be achieved by proper imaging conditions.

Because of the complexity of two-phase flow phenomena, two-phase flow codes rely heavily on empirical correlations. This approach has a number of serious shortcomings. Advances in parallel computing and continuing improvements in computer speed and memory have stimulated the development of numerical simulation tools that rely less on empirical correlations and more on fundamental physics. The objective of this work is to take advantage of developments in massively parallel computing, single-phase computational fluid dynamics of complex systems, and numerical methods for front capturing in two-phase flows to develop a computer code for direct numerical simulation of two-phase flow. This includes bubble/droplet transport, interface deformation and topology change, bubble/droplet interactions, interface mass, momentum and energy transfer.

The authors recently developed an analytic theory of cumulative multibunch beam breakup that includes a linear variation of transverse focusing across the bunch train. The focusing variation saturates the exponential growth of the beam breakup and establishes an algebraic decay of the transverse bunch displacement versus bunch number. In this paper they illustrate how the focusing variation works to suppress multibunch beam breakup, as well as how the mechanism scales with accelerator and beam parameters.

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The 2-D structure of plasma density turbulence in a magnetically confined plasma can potentially be measured using a Thomson scattering system made from components of the Nova laser of LLNL. For a plasma such as NSTX at PPPL, the laser would form an {approximately}10 cm wide plane sheet beam passing vertically through the chamber across the magnetic field. The scattered light would be imaged by a CCD camera viewing along the direction of the magnetic field. The laser energy required to make 2-D images of density turbulence is in the range 1--3 kJ, which can potentially be obtained from a set of frequency-doubled Nd:Glass amplifiers with diameters in the range of 208--315 mm. A laser pulse width of 100 nsec would be short enough to capture the highest spatial frequency components of the expected density fluctuations.

A fully kinetic assessment of the stability properties of toroidal drift modes has been obtained for a case for the Large Helical Device (LHD) [A.Iiyoshi, et al., Plasma Physics and Controlled Nuclear Fusion Research, 1998, Nucl.Fusion 39, 1245 (1999)]. This calculation retains the important effects in the linearized gyrokinetic equation, using the lowest-order ''ballooning representation'' for high toroidal mode number instabilities in the electrostatic limit. Results for toroidal drift waves destabilized by trapped particle dynamics and ion temperature gradients are presented, using three-dimensional magnetohydrodynamics equilibria reconstructed from experimental measurements. The effects of helically-trapped particles and helical curvature are investigated.

Thermally sprayed coating characteristics and mechanical properties are in part a result of the residual stress developed during the fabrication process. The total stress state in a coating/substrate is comprised of the quench stress and the coefficient of thermal expansion (CTE) mismatch stress. The quench stress is developed when molten particles impact the substrate and rapidly cool and solidify. The CTE mismatch stress results from a large difference in the thermal expansion coefficients of the coating and substrate material. It comes into effect when the substrate/coating combination cools from the equilibrated deposit temperature to room temperature. This paper describes a laser-based technique for measuring the curvature of a coated substrate and the analysis required to determine residual stress from curvature measurements. Quench stresses were determined by heating the specimen back to the deposit temperature thus removing the CTE mismatch stress. By subtracting the quench stress from the total residual stress at room temperature, the CTE mismatch stress was estimated. Residual stress measurements for thick (>1mm) spinel coatings with a Ni-Al bond coat on 304 stainless steel substrates were made. It was determined that a significant portion of the residual stress results from the quenching stress of the bond coat and …

The Hanford Site's mission has been to produce nuclear materials for the US Department of Energy (DOE) and its predecessors. A large inventory of radioactive and mixed waste, largely generated during plutonium production, exists in 177 underground single- and double-shell tanks. These wastes are to be retrieved and separated into low-activity waste (LAW) and high-level waste (HLW) fractions. The total volume of LAW requiring immobilization will include the LAW separated from the tank waste, as well as new wastes generated by the retrieval, pretreatment, and immobilization processes. Per the Tri-Party Agreement (1994), both the LAW and HLW will be vitrified. It has been estimated that vitrification of the LAW waste will result in over 500,000 metric tons or 200,000 m{sup 3} of immobilized LAW (ILAW) glass. The ILAW glass is to be disposed of onsite in a near-surface burial facility. It must be demonstrated that the disposal system will adequately retain the radionuclides and prevent contamination of the surrounding environment. This report describes a study of the impacts of systematic glass-composition variation on the responses from accelerated laboratory corrosion tests of representative LAW glasses. A combination of two tests, the product consistency test and vapor-hydration test, is being used to …

Since 1993, the IAEA has made great progress in the implementation of remote monitoring. Equipment has been developed and tested, and installed systems are being used for safeguards purposes. The cost of equipment, the complexity of communication technology, and maintenance of the equipment are challenges that still face the IAEA. Resolution of these challenges will require significant effort. The USSP is committed to assisting the IAEA to overcome these challenges.

Electrical breakdown in thin oxides is assessed by a new bias-temperature ramp technique. No significant effect of radiation exposure on breakdown is observed for high quality thermal and nitrided oxides, up to 20 Mrad(SiO{sub 2}).

Sandia National Laboratories has been developing technologies to support person-to-person collaboration and the efforts of teams in the business and research communities. The technologies developed include knowledge-based design advisors, knowledge management systems, and streamlined manufacturing supply chains. These collaborative environments in which people can work together sharing information and knowledge have required a new approach to software development. The approach includes an emphasis on the requisite change in business practice that often inhibits user acceptance of collaborative technology. Leveraging the experience from this work, they have established a multidisciplinary approach for developing collaborative software environments. They call this approach ``A Holistic Software Development Methodology''.

Since 1981, more than 7,000 wind turbines have been installed in the Altamont Wind Resource Area in north-central California. Currently, about 5,000 turbines are operating. Past research efforts demonstrated that wind turbines frequently kill birds, especially raptors. Little is known about the specific flight and perching behaviors by birds near wind turbines. A better understanding of these interactions may one day yield insights on how to minimize bird fatalities. This Phase 1 progress report summarizes research findings obtained at 20 study plots totaling 785 turbines of various configurations and conducted between March 1998 and February 1999. The authors examined bird use and behaviors and collected data on fatalities at the same turbines throughout the course of the surveys. They completed 745 30-minute point counts (1,702 bird observations) that quantified bird risk behaviors and bird use of the study plots. The four most frequently observed bird species were red-tailed hawks, common ravens, turkey vultures, and golden eagles. During the same period, the authors recorded 95 bird fatalities. Raptors represent 51% (n=49) of the kills found. The data indicate that the relative abundance of species observed does not predict the relative frequency of fatalities per species. Phase II of the research is …

The next great issue on the Russian landscape will be management of its foreign debt. In the near future the United States will be called upon to lead an international program of debt restructuring to assist Russia in overcoming the burden of its debt trap. With debt service obligations equal to 50{percent} of 1999 revenues, Russia has virtually no chance of sustaining a program of economic recovery without debt relief (Hardt, 1999). With some form of debt restructuring a foregone conclusion, Russia, the United States, and world community have a vital stake in searching for creative ways to transform the inevitability of debt restructuring into something of value and constructive to Russia and the problems it faces. This was the rationale behind debt-for-nature swaps which emerged in the early 1980s in Latin American and Eastern Europe as a means of relieving developing nations of their crippling foreign debt. Debt-for-nature swaps served both domestic and international needs by converting a portion of foreign debt, often at steep discounts, into local currency that was then used to fund programs to preserve the environment. The debt swap mechanism provides the prospect of getting something of real value where nothing is expected. The Pacific …

Underdoped high temperature superconductors (HTS) exhibit a normal state for energies E > E{sub g} and/or temperatures T > T{sub 0}, and a pseudogap in their electronic spectrum for E < E{sub g} and/or T{sub 0} > T > {Tc}. Strikingly similar behavior occurs in the transition metal dichalcogenides (TMD) 2H-MX{sub 2}, where M = Ta, Nb, and X = S, Se, both in the normal (T > T{sub 0}) and in the incommensurate charge-density wave (T{sub ICDW} > T > T{sub c}) states. Such strikingly similar behavior has also been seen in the organic layered superconductors (OLS) {kappa}-(ET){sub 2}X, where ET is bis(ethylenedithio)tetrathiafulvalene, and X = Cu[N(CN){sub 2}]Br, and Cu(SCN){sub 2}, both in the normal region T > T{sub SDW} > {Tc} and in the spin-density wave region T{sub SDW} > T > T{sub c}. In all three materials classes, the anomalous transport and thermodynamic properties associated with the pseudogap or density-wave regime are completely independent of the applied magnetic field strength, whereas the same properties below {Tc} are all strongly field-dependent. Hence, the authors propose that the pseudogap in the HTS arises from charge- and/or spin-density waves, and not from either superconducting fluctuations or preformed charged quasiparticle pairs.

The authors report Q-switched operation from an electrically-injected monolithic coupled-resonator structure which consists of an active cavity with InGaAs quantum wells optically coupled to a passive cavity. The passive cavity contains a bulk GaAs region which is reverse-biased to provide variable absorption at the lasing wavelength of 990 nm. Cavity coupling is utilized to effect large changes in output intensity with only very small changes in passive cavity absorption. The device is shown to produce pulses as short as 150 ps at repetition rates as high 4 GHz. A rate equation approach is used to model the Q-switched operation yielding good agreement between the experimental and theoretical pulse shape. Small-signal frequency response measurements also show a transition from a slower ({approximately} 300 MHZ) forward-biased modulation regime to a faster ({approximately} 2 GHz) modulation regime under reverse-bias operation.

During this CRADA, Honeywell FM and T and MoDOT personnel designed a unique scanning system (including both hardware and software) that can be used to perform an automated scan and evaluation of a concrete sample. The specific goals of the CRADA were: (1) Develop a combined system integration, image acquisition, and image analysis approach to mimic the manual scanning and evaluation process. Produce a prototype system which can: (a) automate the scanning process to improve its speed and efficiency; (b) reduce operator fatigue; and (c) improve the consistency of the evaluation process. (2) Capture and preserve the baseline knowledge used by the MoDOT experts in performing the evaluation process. At the present time, the evaluation expertise resides in two MoDOT personnel. Automation of the evaluation process will allow that knowledge to be captured, preserved, and used for training purposes. (3) Develop an approach for the image analysis which is flexible and extensible in order to accommodate the inevitable pathologies that arise in the evaluation process. Such pathologies include features such as cracks and fissures, voids filled with paste or debris, and multiple, overlapping voids. FM and T personnel used image processing, pattern recognition, and system integration skills developed for other …

This paper focuses on a ten-element strategy for streamlining the NEPA process in order to achieve the Act's objectives while easing the considerable burden on agencies, the public, and the judicial system. In other words, this paper proposes a strategy for making NEPA work better and cost less. How these ten elements are timed and implemented is critical to any successful streamlining. The strategy elements discussed in this paper, in no particular order of priority, are as follows: (1) integrate the NEPA process with other environmental compliance and review procedures; (2) accelerate the decision time for determining the appropriate level of NEPA documentation; (3) conduct early and thorough internal EIS (or EA) scoping before public scoping or other public participation begins; (4) organize and implement public scoping processes that are more participatory than confrontational; (5) maintain an up-to-date compendium of environmental baseline information; (6) prepare more comprehensive, broad-scope umbrella EISs that can be used effectively for tiering; (7) encourage preparation of annotated outlines with detailed guidance that serve as a road map for preparation of each EIS or EA; (8) decrease the length and complexity of highly technical portions of NEPA documents; (9) increase and systematize NEPA compliance outreach, training, …

The magnitude of Russian foreign debt, both official bilateral and commercial, compounded by collapse of the Russian economic system, is an obstacle in preventing the Russian Federation from effectively increasing the domestic priority of drawing down its nuclear weapons complex and providing a healthy, competitive environment to its nuclear cities. Debt-for-nature swaps, introduced in the early 1980s, provide debtor nations with a means of converting a portion of foreign debt into local currency, often at steep discounts, to use for purposes such as environmental protection that serve both a domestic and international need. This paper presents the debt-for-nature concept as a model for providing an infusion of funds to further U.S. and international nonproliferation objectives to help stabilize Russian closed city economic conditions through direct work on proliferation problems and remediation of the environment. A specific proposal is presented to demonstrate the utility and efficacy of the dept swap concept through initial collaboration with the city administration of Ozersk. The purpose of the proposal is to facilitate making Ozersk a safe, healthy competitive city, providing useful employment for its scientists and population and converting its superior infrastructure into productive activities.

Wire array Z-pinches on the Z accelerator provide the most intense laboratory source of soft x-rays in the world. The unique combination of a highly-Planckian radiation source with high x-ray production efficiency (15% wall plug), large x-ray powers and energies ( >150 TW, {ge}1 MJ in 7 ns), large characteristic hohlraum volumes (0.5 to >10 cm{sup 3}), and long pulse-lengths (5 to 20 ns) may make Z-pinches a good match to the requirements for driving high-yield scale ICF capsules with adequate radiation symmetry and margin. The Z-pinch driven hohlraum approach of Hammer and Porter [Phys.Plasmas, 6, 2129(1999)] may provide a conservative and robust solution to the requirements for high yield, and is currently being studied on the Z accelerator. This paper describes a multiple region, 0-d hohlraum energetic model for Z-pinch driven hohlraums in four configurations. The authors observe consistency between the models and the measured x-ray powers and hohlraum wall temperatures to within {+-}20% in flux, for the four configurations.

Simulation models of a variable-speed, fixed-pitch wind turbine were investigated to evaluate the feasibility of constraining rotor speed and power output without the benefit of active aerodynamic control devices. A strategy was postulated to control rotational speed by specifying the demanded generator torque. By controlling rotor speed in relation to wind speed, the aerodynamic power extracted by the blades from the wind was manipulated. Specifically, the blades were caused to stall in high winds. In low and moderate winds, the demanded generator torque and the resulting rotor speed were controlled to cause the wind turbine to operate near maximum efficiency. Using the developed models, simulations were conducted of operation in turbulent winds. Results indicated that rotor speed and power output were well regulated. Preliminary investigations of system dynamics showed that, compared to fixed-speed operation, variable-speed operation caused cyclic loading amplitude to be reduced for the turbine blades and low-speed shaft and slightly increased for the tower loads. This result suggests a favorable impact on fatigue life from implementation of the proposed control strategy.

The Experimental Breeder Reactor--II (EBR-II) at Argonne National Laboratory--West (ANL-W) in Idaho, was shutdown in September, 1994 as mandated by the US Department of Energy. This sodium cooled reactor had been in service since 1964, and was to be placed in an industrially and radiologically safe condition for ultimate decommissioning. The deactivation of a liquid metal reactor presents unique concerns. The first major task associated with the project was the removal of all fueled assemblies. In addition, sodium must be drained from systems and processed for ultimate disposal. Residual quantities of sodium remaining in systems must be deactivated or inerted to preclude future hazards associated with pyrophoricity and generation of potentially explosive hydrogen gas. A Sodium Process Facility was designed and constructed to react the elemental sodium from the EBR-II primary and secondary systems to sodium hydroxide for disposal. This facility has a design capacity to allow the reaction of the complete inventory of sodium at ANL-W in less than two years. Additional quantities of sodium from the Fermi-1 reactor are also being treated at the Sodium Process Facility. The sodium environment and the EBR-II configuration, combined with the radiation and contamination associated with thirty years of reactor operation, posed …

This Record of Technical Change updates the technical information included in ''Corrective Action Investigation Plan for Corrective Action Unit 261: Test Cell A Leachfield System, Nevada Test Site, Nevada,'' Revision 0, DOE/NV--515.