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2-D electric fields and drifts near the magnetic separatrix in divertor tokamaks

Description: A 2-D calculation is presented for the transport of plasma in the edge region of a divertor tokamak solving continuity, momentum, and energy balance fluid equations. The model uses anomalous radial diffusion, including perpendicular ion momentum, and classical cross-field drifts transport. Parallel and perpendicular currents yield a self-consistent electrostatic potential on both sides of the magnetic separatrix. Outside the separatrix, the simulation extends to material divertor plates where the incident plasma is recycled as neutral gas and where the plate sheath and parallel currents dominate the potential structure. Inside the separatrix, various radial current terms - from viscosity, charge-exchange and poloidal damping, inertia, and {triangledown}B - contribute to the determining the potential. The model rigorously enforces cancellation of gyro-viscous and magnetization terms from the transport equations. The results emphasize the importance of E x B particle flow under the X-point which depends on the sign of the toroidal magnetic field. Radial electric field (E{sub y}) profiles at the outer midplane are small with weak shear when high L-mode diffusion coefficients are used and are large with strong shear when smaller H-mode diffusion coefficients are used. The magnitude and shear of the electric field (E{sub y}) is larger both when the core toroidal rotation is co-moving with the inductive plasma current and when the ion {triangledown}B-drift is towards the single-null X-point.
Date: November 15, 1998
Creator: Mattor, N.; Porter, G. D.; Rognlien, T. D. & Ryutov, D. D.

1998 Complex Systems Summer School

Description: For the past eleven years a group of institutes, centers, and universities throughout the country have sponsored a summer school in Santa Fe, New Mexico as part of an interdisciplinary effort to promote the understanding of complex systems. The goal of these summer schools is to provide graduate students, postdoctoral fellows and active research scientists with an introduction to the study of complex behavior in mathematical, physical, and living systems. The Center for Nonlinear Studies supported the eleventh in this series of highly successful schools in Santa Fe in June, 1998.
Date: December 15, 1998

Agricultural Research, Education, and Extension Issues in the 105th Congress

Description: The public agricultural research, education, and extension system is comprised of a nationwide network of federal and state agricultural research laboratories and departments, land grant Colleges of Agriculture, colleges of forestry and veterinary medicine, and the nationwide Cooperative Extension System. Although the basic authority to conduct agricultural research and extension programs is permanent, Congress since 1977 has provided funding authority and policy guidance for USDA's in-house research programs, and for federal support for cooperative research, higher education, and extension programs in the states, through a title contained in omnibus farm legislation. This report discusses specific pieces of such legislation and details certain agricultural and food-related appropriations.
Date: January 15, 1998
Creator: Rawson, Jean M.

Los Alamos National Laboratory emergency management plan. Revision 1

Description: The Laboratory has developed this Emergency Management Plan (EMP) to assist in emergency planning, preparedness, and response to anticipated and actual emergencies. The Plan establishes guidance for ensuring safe Laboratory operation, protection of the environment, and safeguarding Department of Energy (DOE) property. Detailed information and specific instructions required by emergency response personnel to implement the EMP are contained in the Emergency Management Plan Implementing Procedure (EMPIP) document, which consists of individual EMPIPs. The EMP and EMPIPs may be used to assist in resolving emergencies including but not limited to fires, high-energy accidents, hazardous material releases (radioactive and nonradioactive), security incidents, transportation accidents, electrical accidents, and natural disasters.
Date: July 15, 1998
Creator: Ramsey, G.F.

Alignment and micro-inspection system

Description: A video microscope system has been designed and installed in the C-tank, a 3-g, high-explosive firing chamber in HEAF (High Explosives Applications Facility in LLNL). This microscope system helps a great deal, not only for precision alignment of the laser beam on the minute target for the Fabry-Perot velocimeter, but also for in situ inspection of the target before and after the experiment. In addition, the video information can also be stored in the PC computer as database documentati
Date: September 15, 1998
Creator: Chau, H; Hodgin, R L & Moua, K

Application of Integrated Reservoir Management and Reservoir Characterization to Optimize Infill Drilling.

Description: A total of 18 wells, 14 producers and 4 injection wells, were drilled and completed during the Field Demonstration portion of the project. These 18 wells are all currently in service, with the producing wells going on-line between May and September 1996, and the injection wells going into service between August and December 1996. Current Unit production is approximately 3,100 BOPD, of which approximately 800 BOPD is being contributed from the 14 Project 10-acre producing wells (Figure 1). A revision in the Statement of Work was approved to allow for the drilling of additional 10-acre infill wells or injection well conversions as budget constraints allow.
Date: January 15, 1998

Application of system simulation for engineering the technical computing environment of the Lawrence Livermore National Laboratorie

Description: This report summarizes an investigation performed by Lawrence Livermore National Laboratory´┐Ż s (LLNL) Scientific Computing & Communications Department (SCCD) and the Garland Location of Raytheon Systems Company (RSC) from April through August.1998. The study assessed the applicability and benefits of utilizing System Simulation in architecting and deploying technical computing assets at LLNL, particularly in support of the ASCI program and associated scientific computing needs. The recommendations and other reported findings reflect the consensus of the investigation team. The investigation showed that there are potential benefits to performing component level simulation within SCCD in support of the ASCI program. To illustrate this, a modeling exercise was conducted by the study team that generated results consistent with measured operational performance. This activity demonstrated that a relatively modest effort could improve the toolset for making architectural trades and improving levels of understanding for managing operational practices. This capability to evaluate architectural trades was demonstrated by evaluating some of the productivity impacts of changing one of the design parameters of an existing file transfer system. The use of system simulation should be tailored to the local context of resource requirements/limitations, technology plans/processes/issues, design and deployment schedule, and organizational factors. In taking these matters into account, we recommend that simulation modeling be employed within SCCD on a limited basis for targeted engineering studies, and that an overall performance engineering program be established to better equip the Systems Engineering organization to direct future architectural decisions and operational practices. The development of an end-to-end modeling capability and enterprise-level modeling system within SCCD is not warranted in view of the associated development requirements and difficulty in determining firm operational performance requirements in advance of the critical architectural decisions. These recommendations also account for key differences between the programmatic and institutional environments at LLNL and RSC.
Date: September 15, 1998
Creator: Boyd, V; Edmunds, T; Minuzzo, K; Powell, E & Roche, L

Atomic Structure and Properties of Extended Defects in Silicon

Description: The Z-contrast technique represents a new approach to high-resolution electron microscopy allowing for the first time incoherent imaging of materials on the atomic scale. The key advantages of the technique, an intrinsically higher resolution limit and directly interpretable, compositionally sensitive imaging, allow a new level of insight into the atomic configurations of extended defects in silicon. This experimental technique has been combined with theoretical calculations (a combination of first principles, tight binding, and classical methods) to extend this level of insight by obtaining the energetic and electronic structure of the defects.
Date: October 15, 1998
Creator: Buczko, R.; Chisholm, M.F.; Kaplan, T.; Maiti, A.; Mostoller, M.; Pantelides, S.T. et al.

Back Contact Effects on the Electro-Optical Properties of CdTe/CdS Solar Cells

Description: Studies of junction photoluminescence (PL) in CdTe/CdS solar cells reveal that back-contact application produces a dramatic qualitative change in the junction picosecond-PL spectrum. Prior to contact application, the spectrum has two peaks at energies of 1.501 eV and 1.457 eV, corresponding to recombination in regions of CdTeS alloy with 2% and 12% sulfur content, respectively. After contact application, the spectrum consists of a single broad peak at 1.48 eV. Previous studies have shown that the nitric-phosphoric (NP) etch used in the contact procedure produces a layer of elemental tellurium (Te) on the CdTe surface. We postulate that the change in the near-junction PL spectrum is caused by a grain-boundary field effect due to perturbations of the grain-boundary conductivity and Fermi level.
Date: October 15, 1998
Creator: Levi, D. H.; Albin, D. S.; Gessert, T. A. (National Renewable Energy Laboratory) & Woods, L. M. (Department of Electrical Engineering, Colorado State University, Ft. Collins, CO)

Biological Monitoring Program for East Fork Poplar Creek

Description: In May 1985, a National Pollutant Discharge Elimination System (NPDES) permit was issued for the Oak Ridge Y-12 Plant. As a condition of the permit, a Biologicai Monitoring and Abatement Program (BMAP) was developed to demonstrate that the effluent limitations established for the Y-12 Plant protect the classified uses of the receiving stream (East Fork Poplar Creek; EFPC), in particular, the growth and propagation of aquatic life (Lear et al. 1989). A second objective of the BMAP is to document the ecological effects resulting from the implementation of a water pollution control program designed to eliminate direct discharges of wastewaters to EFPC and to minimize the inadvertent release of pollutants to the environment. Because of the compiex nature of the discharges to EFPC and the temporal and spatial variability in the composition of the discharges, a comprehensive, integrated approach to biological monitoring was developed. A new permit was issued to the Y-12 Plant on April 28, 1995 and became effective on July 1, 1995. Biological monitoring continues to be required under the new permit. The BMAP consists of four major tasks that reflect different but complementary approaches to evaluating the effects of the Y-12 Plant discharges on the aquatic integrity of EFPC, These tasks are (1) toxicity monitoring, (2) biological indicator studies, (3) bioaccumuiation studies, and (4) ecological surveys of the periphyton, benthic macro invertebrate, and fish communities. Monitoring is currently being conducted at five sites, although sites maybe excluded and/or others added depending upon the specific objectives of the various tasks. Criteria used in selecting the sites include: (1) location of sampling sites used in other studies, (2) known or suspected sources of downstream impacts, (3) proximity to U.S. Department of Energy (DOE) Oak Ridge Reservation (ORR) boundaries, (4) concentration of mercury in the adjacent floodplain, (5) appropriate habitat ...
Date: October 15, 1998
Creator: Adams, S.M.; Christensen, S.W.; Greeley, M.S.jr; Hill, W.R.; Kszos, L.A.; McCarthy, J.F. et al.

[Calibration methods for neutron diagnostics at Omega]. DOE/NLUF final report

Description: The investigation of Calibration Methods for Neutron Diagnostics at Omega is still underway. The data shown here is a compilation of measurements taken at Omega during the time of the grant. The data set has been updated with additional information taken this year. The neutron yield from an ICF event was determined by measuring the activity of an aluminum sample activated by target-produced DT neutrons. The radioactive nuclei {sup 24}Na and {sup 27}Mg, which were produced via the {sup 27}Al(n,{alpha}){sup 24}Na and {sup 27}Al(n,p){sup 27}Mg direct reactions, beta decay to excited states of {sup 24}Mg and {sup 27}Al respectively. These excited states then emitted gamma rays as the nuclei de-excite to their respective ground states. The gamma rays are detected and counted. From their numbers the neutron yield is determined.
Date: January 15, 1998
Creator: Padalino, S.

Campaign Finance Reform: A Legal Analysis of Issue and Express Advocacy

Description: Issue advocacy communications have become increasingly popular over the federal election cycles. Often these advertisements could be interpreted to favor or disfavor certain candidates, while also serving to inform the public about a policy issue. However, unlike communications that expressly advocate the election or defeat of a clearly identified candidate, the Supreme Court has ruled that issue ads are constitutionally protected First Amendment speech and cannot be regulated.
Date: May 15, 1998
Creator: Whitaker, L. Paige

Comparison of Analytical and Experimental Effectiveness of Four-Row Plate-Fin-Tube Heat Exchangers with Water, R-22, and R-410A

Description: The analytical solutions of heat exchanger effectiveness for four-row crcmilow, cross-countertlow and cross-paralleltlow have been derived in the recent study. The main objective of this study is to investigate the etlkct of heat exchawger tlow conllguration on thermal performance with refrigerant mixtures. Difference of heat exchanger effectiveness for all flow arrangements relative to an analytical many-row solution has been analyzed. A comparison of four-row cross cou~ltet-ilow heat exchanger effectiveness between analytical solutions and experimental data with water, R-22, and R-4 10A is presented.
Date: November 15, 1998
Creator: Baxter, V.D.; Chen, T.D. & Conklin, J.C.

Comparison of natural convection heat exchangers for solar water heating systems

Description: Thermosyphon heat exchangers are used in indirect solar water heating systems to avoid using a pump to circulate water from the storage tank to the heat exchanger. In this study, the authors consider the effect of heat exchanger design on system performance. They also compare performance of a system with thermosyphon flow to the same system with a 40W pump in the water loop. In the first part of the study, the authors consider the impact of heat exchanger design on the thermal performance of both one- and two-collector solar water heaters. The comparison is based on Solar Rating and Certification Corporation (SRCC) OG300 simulations. The thermosyphon heat exchangers considered are (1) a one-pass, double wall, 0.22 m{sup 2}, four tube-in-shell heat exchanger manufactured by AAA Service and Supply, Inc., (the Quad-Rod); (2) a two-pass, double wall, 0.2 m{sup 2}, tube-in-shell made by Heliodyne, Inc., but not intended for commercial development; (3) a one-pass, single wall, 0.28 m{sup 2}, 31 tube-in-shell heat exchanger from Young Radiator Company, and (4) a one-pass single-wall, 0.61 m{sup 2}, four coil-in-shell heat exchanger made by ThermoDynamics Ltd. The authors compare performance of the systems with thermosyphon heat exchangers to a system with a 40 W pump used with the Quad-Rod heat exchanger. In the second part of the study, the effects of reducing frictional losses through the heat exchanger and/or the pipes connecting the heat exchanger to the storage tank, and increasing heat transfer area are evaluated in terms of OG300 ratings.
Date: September 15, 1998
Creator: Davidson, J. & Liu, W.

Concentration of uranium and plutonium in unsaturated spent fuel tests.

Description: Commercial spent fuel is being tested under oxidizing conditions at 90 C in drip tests with simulated groundwater to evaluate its long-term performance in a potential repository at Yucca Mountain [1-4]. The tests allow us to monitor the dissolution behavior of the spent fuel matrix and the release rates of individual radionuclides. This paper reports the U and Pu concentrations in the leachates of drip tests during 3.7 years of reaction. Changes in these concentrations are correlated with changes in the measured pH and the appearance of alteration products on the fuel surface. Although there is little thermodynamic information at 90 C for either uranyl or plutonium compounds, some data are available at 25 C [5-8]. The literature data for the U and Pu solubilities of U and Pu compounds were compared to the U and Pu concentrations in the leachates. We also compare Wilson's [9] U and Pu concentrations in semi-static tests at 85 C on spent fuel with our results.
Date: April 15, 1998
Creator: Finn, P. A.

Continuous, Rapid Production of Uniform Microparticles by Electrodispersion

Description: Ultrafine particles constitute the key building blocks for diverse advanced structural and functional materials, such as high-performance ceramics and alloys. These advanced materials have tremendous impact in many areas, including catalysis, separations, electronics, energy production processes, and environmental applications. Of particular importance, nanophase ceramic or metallic materials that contain nanosized (<100 nm) particles/grains show dramatically improved performance (mechanical, electrical, optical, magnetic, and/or catalytic). The characteristics of ultrafine particles (i.e. size, morphology, monodispersity, purity, and homogeneity of composition) directly determine the properties of the materials that are made from them. Thus, the future application of advanced materials depends strongly on the capability to produce particles with outstanding characteristics.
Date: November 15, 1998
Creator: DePaoli, D.W. & Hu, M.Z.-C.

Corrective Action Investigation Plan for Corrective Action Unit 486: Double Tracks RADSAFE Area Nellis Air Force Range, Nevada

Description: This Corrective Action Investigation Plan (CAIP) has been developed in accordance with the Federal Facility Agreement and Consent Order (FFACO) that was agreed to by the US Department of Energy, Nevada Operations Office (DOE/NV); the State of Nevada Division of Environmental Protection (NDEP); and the US Department of Defense (FFACO, 1996). The CAIP is a document that provides or references all of the specific information for investigation activities associated with Corrective Action Units (CAUs) or Corrective Action Sites (CASs). According to the FFACO, CASs are sites potentially requiring corrective action(s) and may include solid waste management units or individual disposal or release sites (FFACO, 1996). Corrective Action Units consist of one or more CASs grouped together based on geography, technical similarity, or agency responsibility for the purpose of determining corrective actions. This CAIP contains the environmental sample collection objectives and the criteria for conducting site investigation activities at CAU 486, the Double Tracks Radiological Safety (RADSAFE) Area (DTRSA) which is located on the Nellis Air Force Range 71North (N), west of the Tonopah Test Range (TTR). The TTR, included in the Nellis Air Force Range Complex, is approximately 255 kilometers (km) (140 miles [mi]) northwest of Las Vegas, Nevada (Figure 1-1). Corrective Action Unit 486 is comprised of CAS 71-23-001-71DT consisting of two areas of concern referred to as the vehicle decontamination area and the animal burial pit. The DTRSA is located on the west side of the Cactus Range approximately 8 km (5 mi) southwest of the Cactus Spring gate at the intersection of the Cactus Spring Road and the Double Tracks Control Point Road (Figure 1-2). The DTRSA was used during May 1963 to decontaminate vehicles, equipment, personnel, and animals from the Double Tracks test. The DTRSA is one of three areas identified as a potential location for ...
Date: October 15, 1998
Creator: Vegas, IT Las

Creating metallic under-dense radiators by electron beam heating prior to laser impact

Description: A pulsed, relativistic electron beam can heat a metal foil to a plasma state, and initiate an expanding flow into vacuum. At a given time in its evolution, this flow fills a nearly spherical volume with nearly uniform density, assuming a rapid expansion prior to any condensation. A metal cloud produced in this way can serve as a target of intense laser illumination to create an under-dense radiator of x-rays. The phrase ''under-dense radiator'' means that the cloud, assumed ionized, has a plasma density that is less than the critical density for the wavelength of the laser light. The example described here is of a 2 {micro}g copper foil 23 {micro}m thick and 0.16 mm in diameter, heated by 8 mJ of electron beam energy in as short a time as possible, perhaps under 50 ns. The electron beam pulse must be at least 140 nC at 100 keV in order to transit the foil and deposit 8 mJ. A 50 ns pulse focused on the target would have a current of 2.8 A, and a current density of 14 kA/cm{sup 2}. The initial plasma temperature is 0.5 eV. After 300 ns, the flow has expanded to fill a nearly spherical volume of 1 mm diameter, with a nearly uniform copper density of 1.5 x 10{sup 20} cm{sup {minus}3}. The leading edge of the cloud is expanding at 1700 m/s, while flow at the original position of the foil surface expands at 150 m/s. This cloud is nearly stationary during the short time of a laser pulse at the National Ignition Facility (NIF).
Date: December 15, 1998
Creator: Garcia, M

Cryogenic D-T fuel layers formed in 1mm spheres by beta-layering

Description: Solid D-T fuel smoothly layered on the interior of spherical capsules is required for all inertial confinement fusion ignition target designs. One process for forming these layers, beta-layering, has been studied in surrogate geometries such as open cylinders or tori to allow accurate characterization of the DT surfaces. We present the first results from beta layering in 1 mm spherical containers, such as will be used in upcoming Omega experiments. These results are also directly relevant to ignition capsules for the National Ignition Facility. We find that layers can form with roughness as small as 1.2 microns rms, and that results are strongly dependent upon freezing rate as well as layer thickness.
Date: October 15, 1998
Creator: Bernat, T P; Burmann, J; Collins, G W; Kozioziemski, B; Mapoles, E R; Pipes, J et al.

Current Status of Health and Safety Issues of Sodium/Metal Chloride (Zebra) Batteries

Description: This report addresses environmental, health, and safety (EH&S) issues associated with sodium/ metal chloride batteries, in general, although most references to specific cell or battery types refer to units developed or being developed under the Zebra trademark. The report focuses on issues pertinent to sodium/metal chloride batteries and their constituent components; however, the fact that some ''issues'' arise from interaction between electric vehicle (EV) and battery design compels occasional discussion amid the context of EV vehicle design and operation. This approach has been chosen to provide a reasonably comprehensive account of the topic from a cell technology perspective and an applications perspective.
Date: December 15, 1998
Creator: Trickett, D.

Decontamination of Radionuclides from Concrete During and After Thermal Treatment

Description: The objective was to clarify from the theoretical viewpoint the mechanical, diffusional, thermodynamic and electromagnetic aspects of the decontaminations problem, by means of developing a powerful computational model to evaluate the effect of a very rapid heating regime on the on the contaminated concrete walls or slabs. The practical objective was to assess the feasibility of the microwave heating scheme envisaged and determine its suitable parameters such as power and duration. This objective was complementary to, but separate from, the chemical and nuclear aspects of long-time processes that led to the contamination and various conceivable alternative methods of decontamination which were investigated by Dr. Brian Spalding of Oak Ridge National Laboratory, with whom the start-up phase of this project was coordinated.
Date: September 15, 1998
Creator: Bazant, Z. P.