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Science & Technology Review, April 1998

Description: Serial publication produced by Lawrence Livermore National Laboratory regarding the institution's research in technology to address concerns about energy, bioscience, and the environment. "Science & Technology Review is published ten times a year to communicate, to a broad audience, the Laboratory's scientific and technological accomplishments in fulfilling its primary missions. The publication's goal is to help readers understand these accomplishments and appreciate their value to the individual citizen, the nation, and the world" (inside cover).
Date: April 1998
Creator: Lawrence Livermore National Laboratory
Partner: UNT Libraries Government Documents Department

Plan for metal barrier selection and testing for NNWSI

Description: The Department of Energy`s Nevada Nuclear Waste Storage Investigations (NNWSI) Project is evaluating a site at Yucca Mountain in Nevada as a geological repository for the storage of high-level nuclear waste. The Nuclear Waste Management Projects (NWMP) at Lawrence Livermore National Laboratory (LLNL) has the responsibility for design, testing, and performance analysis of the NNWSI waste packages. One portion of this work is the selection and testing of the material for container construction. The anticipated container design is for this material to be a corrosion resistant metal called the metal barrier. This document is the publication version of the Scientific Investigation Plan (SIP) for the Metal Barrier Selection and Testing Task. The SIP serves as a formal planning document for the investigation and is used to assign quality assurance levels to the activities of the task. This document is an informal version for information distribution and has the sections on ``Schedule and Milestones`` and ``Quality Assurance Level Assignment Sheets`` removed.
Date: December 1, 1987
Creator: Halsey, W.G. & McCright, R.D.
Partner: UNT Libraries Government Documents Department

Plan for spent fuel waste form testing for NNWSI [Nevada Nuclear Waste Storage Investigations]

Description: The purpose of spent fuel waste form testing is to determine the rate of release of radionuclides from failed disposal containers holding spent fuel, under conditions appropriate to the Nevada Nuclear Waste Storage Investigations (NNWSI) Project tuff repository. The information gathered in the activities discussed in this document will be used: to assess the performance of the waste package and engineered barrier system (EBS) with respect to the containment and release rate requirements of the Nuclear Regulatory Commission, as the basis for the spent fuel waste form source term in repository-scale performance assessment modeling to calculate the cumulative releases to the accessible environment over 10,000 years to determine compliance with the Environmental Protection Agency, and as the basis for the spent fuel waste form source term in repository-scale performance assessment modeling to calculate cumulative releases over 100,000 years as required by the site evaluation process specified in the DOE siting guidelines. 34 refs.
Date: November 1, 1987
Creator: Shaw, H.F.
Partner: UNT Libraries Government Documents Department

Plan for waste package environment for NNWSI [Nevada Nuclear Waste Storage Investigations]

Description: The purpose and objective of the Waste Package Environment task is to establish and characterize the environmental processes affecting the near-field repository host rock after waste package emplacement. These processes, which reflect the perturbation induces in the environment by engineering effects and by the waste package decay heat and radiation, will influence chemical, mineralogical and hydrological features of the environment. The thermal and radiation output of the waste packages will change with time, resulting in an environment in which the chemical, mineralogical and physical attributes may also change through time. To assure that waste package design considerations reflect the characteristics of this evolving environment, it is necessary to determine the range of conditions that may develop in the pre- and post-emplacement waste package environment. To assure that the emplacement configurations do not compromise the lifetime of the repository or the waste packages, the design of the emplacement configuration must also consider the environmental features. Recognition of these requirements resulted in the development of the issue an information needs. 20 refs.
Date: February 1, 1988
Creator: Glassley, W.E.
Partner: UNT Libraries Government Documents Department

Planar LIF observation of unburned fuel escaping the upper ring-land crevice in an SI engine

Description: PLIF has been used to observe the in-cylinder transport of unburned fuel that, while trapped in the ring-land and ring-groove crevices, survives combustion in the propagating flame. Away from the top-ring gap, we detect a wall-jet comprised of unburned charge exiting the top ring-land crevice opening. At the location of the top-ring gap, we observed unburned fuel lying in the cool boundary layer along the cylinder wall during the later stages of the expansion stroke. This layer is scraped into the roll-up vortex during the exhaust stroke. These data lead us to conclude that away from the end gap, unburned, high pressure charge, trapped between the two compression rings escapes as a wall jet after ring-reversal near the bottom center. Conversely, at the ring gap, when the cylinder pressure drops below the pressure between the compression rings, the trapped charge escapes through the gap and forms a thin layer on the cylinder wall.
Date: January 1, 1997
Creator: Green, R.M. & Cloutman, L.D.
Partner: UNT Libraries Government Documents Department

Plasma arc heated secondary combustion chamber

Description: This paper describes a secondary combustion chamber (SCC) for hazardous waste treatment systems that uses a plasma arc torch as the heat source. Developed under a cooperative research and development agreement (CRADA) between Retech, Inc. and Lawrence Livermore National Laboratory (LLNL), the unit is intended primarily to handle the off-gas from a Plasma Arc Centrifugal Treatment (PACT) system. ft is designed to heat the effluent gas which may contain volatile organic compounds, and maintain the gas temperature above 1000 C for two seconds or more. The benefits of using a plasma arc gas heater are described in comparison to a conventional fossil fuel heated SCC. Thermal design considerations are discussed. Analysis and experimental results are presented to show the effectiveness in destroying hazardous compounds and reducing the total volume of gaseous emissions.
Date: February 1, 1995
Creator: Haun, R.; Paulson, B.; Schlienger, M.; Goerz, D.; Kerns, J. & Vernazza, J.
Partner: UNT Libraries Government Documents Department

Plasma diagnostic reflectometry

Description: Theoretical and experimental studies of plasma diagnostic reflectometry have been undertaken as a collaborative research project between the Lawrence Livermore National Laboratory (LLNL) and the University of California Department of Applied Science Plasma Diagnostics Group under the auspices of the Laboratory Directed Research and Development Program at LLNL. Theoretical analyses have explored the basic principles of reflectometry to understand its limitations, to address specific gaps in the understanding of reflectometry measurements in laboratory experiments, and to explore extensions of reflectometry such as ultra-short-pulse reflectometry. The theory has supported basic laboratory reflectometry experiments where reflectometry measurements can be corroborated by independent diagnostic measurements.
Date: February 26, 1996
Creator: Cohen, B.I.; Afeyan, B.B.; Garrison, J.C.; Kaiser, T.B.; Luhmann, N.C. Jr.; Domier, C.W. et al.
Partner: UNT Libraries Government Documents Department

Plasma electrode pockels cell for ICF lasers

Description: In a plasma-electrode Pockels cell (PEPC), plasma discharges serve as transparent electrodes on each side of, an electrooptic crystal such as KDP. These plasmas facilitate rapid and uniform charging and discharging of the crystal. The authors describe PEPC technology deployed on Beamlet and envisioned for the National Ignition Facility. Performance on Beamlet is discussed in detail. They also discuss models which have shed light on PEPC operation. These models describe both the high-voltage sheath that forms near the crystal surface and the characteristics of the bulk plasma column.
Date: July 7, 1995
Creator: Rhodes, M.A.; Boley, C.D.; Tarditi, A.G. & Bauer, B.S.
Partner: UNT Libraries Government Documents Department

Pollution prevention cost savings potential

Description: The waste generated by DOE facilities is a serious problem that significantly impacts current operations, increases future waste management costs, and creates future environmental liabilities. Pollution Prevention (P2) emphasizes source reduction through improved manufacturing and process control technologies. This concept must be incorporated into DOE`s overall operating philosophy and should be an integral part of Total Quality Management (TQM) program. P2 reduces the amount of waste generated, the cost of environmental compliance and future liabilities, waste treatment, and transportation and disposal costs. To be effective, P2 must contribute to the bottom fine in reducing the cost of work performed. P2 activities at LLNL include: researching and developing innovative manufacturing; evaluating new technologies, products, and chemistries; using alternative cleaning and sensor technologies; performing Pollution Prevention Opportunity Assessments (PPOAs); and developing outreach programs with small business. Examples of industrial outreach are: innovative electroplating operations, printed circuit board manufacturing, and painting operations. LLNL can provide the infrastructure and technical expertise to address a wide variety of industrial concerns.
Date: December 1, 1994
Creator: Celeste, J.
Partner: UNT Libraries Government Documents Department

Polyimide capsules may hold high pressure DT fuel without cryogenic support for the National Ignition Facility indirect-drive targets

Description: New target designs for the Omega upgrade laser and ignition targets in the National Ignition Facility (NIF) require thick (80 - 100 {micro}m) cryogenic fuel layers. The Omega upgrade target will require cryogenic handling after initial fill because of the high fill pressures and the thin capsule walls. For the NIF indirectly driven targets, a larger capsule size and new materials offer hope that they can be built, filled and stored in a manner similar to the targets used in the Nova facility without requiring cryogenic handling.
Date: March 26, 1997
Creator: Sanchez, J.J. & Letts, S.A.
Partner: UNT Libraries Government Documents Department

Polymers replace glass in Nova fuel capsules

Description: The glass fuel-capsule designs used in previous laser-fusion research are not adaptable to the implosion-physics requirements of Nova and other more powerful laser facilities that may be available in the future. As one tries to learn more about the physics of high-density compression, it becomes increasingly important to replace the glass with lower-Z material. Accordingly, the authors have shut down the high-temperature drop-tower furnaces they used to make glass capsules, and they are focusing all their efforts on developing new techniques for making polymer capsules. These capsules are ten times larger in diameter than the glass capsules used in the early days of laser-fusion research, but they are still only one-tenth as large as a high-gain capsule must be. The polymer capsules will be used in classified indirect-drive targets. This article describes how the decisions were made on which polymers to use in the NOVA fuel capsules, the techniques explored, and the properties of the prototype capsules.
Date: January 1, 1986
Creator: Burnham, A.K.
Partner: UNT Libraries Government Documents Department

Preliminary definition of geophysical regions for the Middle East and North Africa

Description: The ability to calibrate seismic stations to improve the monitoring of the Comprehensive Test Ban Treaty is partially limited by the availability of seismic events with known locations and source properties. To confidently extrapolate from these events to aseismic regions, and to properly account for discontinuities in seismic properties requires accurate geophysical models. This paper lays out a preliminary, first-order, regionalization of the Middle East and North African (MENA) region. The model specifies boundaries and velocity structures based on the geology and tectonics of the region, previously published studies, and empirical data observations by the LLNL group. This model is a starting point and is expected to be improved and refined by comparisons with ongoing tomography efforts and the collection of new data. We anticipate that this model and its successors will prove useful as a background model in the process of forming station calibration maps based on intelligent interpolation techniques such as kriging. We also hope the model, as it improves and demonstrates some predictive power, will provide a reference model for broader CTBT research efforts in detection, location and discrimination as well as other aspects of earth science.
Date: December 1998
Creator: Sweeney, J. J. & Walter, B.
Partner: UNT Libraries Government Documents Department

Preliminary description of small block mineralogical features, data report

Description: The large block heater test, to be conducted at Fran Ridge (Lin et al., 1994), is designed to provide a database with which to test codes that simulate hydrological, geochemical, and geomechanical processes that may occur within the repository block. The geochemical processes that may occur include rock-water interaction within the matrix of fracture bounded blocks, and with the minerals that line fractures (see, for example, Buscheck and Nitao, 1992,1993ab, 1994; Glassley, 1993). As a first step in evaluating these interactions, characterization of the fractures, and of the matrix that is adjacent to those fractures, must be completed Characterization of the fractures and matrix before the large block test is started will allow a `baseline` set of data to be collected that will describe the properties of the large block prior to the test. After the test is completed, the block will be dismembered and characterization of the matrix and fractures will be repeated. Changes in matrix and fracture mineralogies will allow documentation of the mineralogical consequences of rock-water interaction resulting from heating of tuff under the conditions of the test.
Date: February 3, 1998
Creator: Glassley, W., LLNL
Partner: UNT Libraries Government Documents Department

Preliminary design report of a relativistic-Klystron two-beam-accelerator based power source for a 1 TeV center-of-mass next linear collider

Description: A preliminary point design for an 11.4 GHz power source for a 1 TeV center-of-mass Next Linear Collider (NLC) based on the Relativistic-Klystron Two-Beam-Accelerator (RK-TBA) concept is presented. The present report is the result of a joint LBL-LLNL systems study. consisting of three major thrust areas: physics, engineering, and costing. The new RK-TBA point design, together with our findings in each of these areas, are reported.
Date: February 22, 1995
Creator: Yu, S.; Goffeney, N. & Henestroza, E.
Partner: UNT Libraries Government Documents Department

Preliminary evaluation of alterant geophysical tomography in welded tuff

Description: The ability of alterant geophysical tomography to delineate flow paths in a welded tuff rock mass has been preliminarily evaluated based on the results of a field experiment. Electromagnetic measurements were made before, during and after a water-based, dye tracer flowed through the rock mass. Alterant geophysical tomographs were generated and compared with independent evidence - borescope logs, neutron logs and dyed rock samples. Anomalies present in the tomograph match the location and orientation of fractures mapped with a borescope. The location of tracer-strained fractures coincides with the location of some image anomalies; other geophysical anomalies exist where tracer-strained fractures were not observed, perhaps due to poor core recovery. Additional drilling to locate stained flow paths and other experiments are planned so that the applicability of the technique can be further evaluated. 7 refs., 5 figs.
Date: February 1, 1985
Creator: Ramirez, A.L. & Daily, W.D.
Partner: UNT Libraries Government Documents Department

Preliminary field evaluation of high efficiency steel filters

Description: The authors have conducted an evaluation of two high efficiency steel filters in the exhaust of an uranium oxide grit blaster at the Y-12 Plant in Oak Ridge Tennessee. The filters were installed in a specially designed filter housing with a reverse air-pulse cleaning system for automatically cleaning the filters in-place. Previous tests conducted on the same filters and housing at LLNL under controlled conditions using Arizona road dust showed good cleanability with reverse air pulses. Two high efficiency steel filters, containing 64 pleated cartridge elements housed in the standard 2{prime} x 2{prime} {times} l{prime} HEPA frame, were evaluated in the filter test housing using a 1,000 cfm slip stream containing a high concentration of depleted uranium oxide dust. One filter had the pleated cartridges manufactured to the authors specifications by the Pall Corporation and the other by Memtec Corporation. Test results showed both filters had a rapid increase in pressure drop with time, and reverse air pulses could not decrease the pressure drop. The authors suspected moisture accumulation in the filters was the problem since there were heavy rains during the evaluations, and the pressure drop of the Memtec filter decreased dramatically after passing clean, dry air through the filter and after the filter sat idle for one week. Subsequent laboratory tests on a single filter cartridge confirmed that water accumulation in the filter was responsible for the increase in filter pressure drop and the inability to lower the pressure drop by reverse air pulses. No effort was made to identify the source of the water accumulation and correct the problem because the available funds were exhausted.
Date: November 1, 1994
Creator: Bergman, W.; Larsen, G.; Lopez, R.; Wilson, K.; Simon, K. & Frye, L.
Partner: UNT Libraries Government Documents Department

A preliminary guidebook for identifying stratigraphic contacts at the Nevada Test Site

Description: Lithologic variation, regional depositional trends, and the lack of written guidelines have resulted in inconsistencies in the recognition of stratigraphic contacts in drill holes at the Nevada Test Site (NTS). Stratigraphic identification, based on mineralogy of discrete samples, can be augmented by geophysical logs and downhole movies to more accurately and consistently locate contacts between units. Criteria are established for locating the base of the Pahute Mesa ash-flow tuff, the top of the Ammonia Tanks ash-flow tuff, the top of the Ammonia Tanks bedded tuff, and the top and the base of the Rainier Mesa Tuff.
Date: January 1, 1992
Creator: Pawloski, G.A.; McKague, H.L.; Wagoner, J.L. & McKinnis, W.B.
Partner: UNT Libraries Government Documents Department

Preliminary investigation of an additive approach to the fabrication of precision aspheres

Description: We report progress in the aspherization of precision optical substrates via deposition of graded period Mo/Si multilayer coatings using a masking technique. These preliminary results show good agreement between the measured and desired thickness profiles over 85% of the sample, however, thickness deviations of up to 7 % are observed in the central area. The errors are attributed to misalignments of the mask relative to the substrate during deposition.
Date: May 24, 1996
Creator: Weber, F.W.; Montcalm, C.; Vernon, S.P. & Kania, D.R.
Partner: UNT Libraries Government Documents Department

Preliminary investigation of grain refinement in a U-0.2 wt % V alloy casting by true isothermal transformation at 516{degree}C

Description: Laboratory-scale isothermal transformation from beta phase to alpha phase at 516 C was accomplished using one U-0.2 wt % V alloy composition and with specimens up to 7.6 mm in thickness. Gravity was used to transfer individual specimens from a furnace at 720 C to one at 516 C. The lower-temperature, furnace contained two copper blocks between which the specimens were quenched by contact. The furnace also contained a partial atmosphere of helium. Results duplicate those of Reisse et al. at this temperature. Their work was done on smaller samples. Grain sizes obtained were consistently ASTM 7 to 8 (20 to 30 {mu}m), indicating that the cooling rates at the center of even the thicker samples were adequate to miss the nose of the (upper) TTT curve. The microstructure obtained, including the grain size, appears to be equivalent to that obtained by carefully controlled wrought processing, but we believe these castings lack the strong crystallographic textures that exist in wrought products.
Date: July 1, 1995
Creator: Wood, D.H.; Flores, R. & Kershaw, R.P.
Partner: UNT Libraries Government Documents Department

Optimized, diode pumped, Nd:glass, prototype regenerative amplifier for the National Ignition Facility (NIF)

Description: The National Ignition Facility (NIF) will house a 2 MJ Nd:glass laser system to be used for a broad range of inertial confinement fusion experiments. This record high energy laser output will be initiated by a single low energy, fiber -based master oscillator which will be appropriately shaped in time and frequency prior to being split into 48 beams for intermediate amplification. These 48 intermediate energy beams will feed the 192 main amplifier chains. We report on the baseline design and test results for an amplifier subsystem in the intermediate amplifiers. The subsystem is based on a diode pumped, Nd:glass regenerative amplifier. The amplifier is comprised fo a linear, folded, TEM{sub 00}, 4.5m long cavity and represents the highest gain (approximately 10{sup 7}) component in the NIF laser system. Two fundamentally important requirements for this amplifier include output energy of 20 mJ and square pulse distortion of less than 1.45. With a single 48 bar 4.5kW peak power diode array and lens duct assembly we pump a 5 mm diameter X 50 mm long Nd-doped, phosphate glass rod, and amplify the mode matched, temporally shaped (approximately 20ns in duration)oscillator seed pulse to 25 mJof output energy with a very acceptable square pulse distortion of 1.44. This most recent design of the regenerative amplifier has increased the performance and reduced the cost, enabling it to become a solid baseline for the NIF laser system.
Date: December 1, 1997
Creator: Martinez, M.; Crane, J.; Penko, F. & Browning, D.
Partner: UNT Libraries Government Documents Department

Optimizing bandwidth utilization in packet based telemetry systems

Description: A consistent theme in spacecraft telemetry system design is the desire to obtain maximum bandwidth utilization given a fixed transmission capability (usually due to cost/weight criteria). Extensions to basic packetization telemetry architectures are discussed which can facilitate a reduction in the amount of actual data telemetered, without loss of data quality. Central to the extensions are the establishment of an ``intelligent`` telemetry process, which can evaluate pending data to be telemetered, and act to compress, discard, or re-formulate data before actual transmission to ground stations.
Date: October 17, 1995
Creator: Kalibjian, J.R.
Partner: UNT Libraries Government Documents Department

Optimizing parallel reduction operations

Description: A parallel program consists of sets of concurrent and sequential tasks. Often, a reduction (such as array sum) sequentially combines values produced by a parallel computation. Because reductions occur so frequently in otherwise parallel programs, they are good candidates for optimization. Since reductions may introduce dependencies, most languages separate computation and reduction. The Sisal functional language is unique in that reduction is a natural consequence of loop expressions; the parallelism is implicit in the language. Unfortunately, the original language supports only seven reduction operations. To generalize these expressions, the Sisal 90 definition adds user-defined reductions at the language level. Applicable optimizations depend upon the mathematical properties of the reduction. Compilation and execution speed, synchronization overhead, memory use and maximum size influence the final implementation. This paper (1) Defines reduction syntax and compares with traditional concurrent methods; (2) Defines classes of reduction operations; (3) Develops analysis of classes for optimized concurrency; (4) Incorporates reductions into Sisal 1.2 and Sisal 90; (5) Evaluates performance and size of the implementations.
Date: June 1, 1995
Creator: Denton, S.M.
Partner: UNT Libraries Government Documents Department

Optimizing tertiary storage organization and access for spatio-temporal datasets

Description: We address in this paper data management techniques for efficiently retrieving requested subsets of large datasets stored on mass storage devices. This problem represents a major bottleneck that can negate the benefits of fast networks, because the time to access a subset from a large dataset stored on a mass storage system is much greater that the time to transmit that subset over a network. This paper focuses on very large spatial and temporal datasets generated by simulation programs in the area of climate modeling, but the techniques developed can be applied to other applications that deal with large multidimensional datasets. The main requirement we have addressed is the efficient access of subsets of information contained within much larger datasets, for the purpose of analysis and. interactive visualization. We have developed data partitioning techniques that partition datasets into ``clusters`` based on analysis of data access patterns and storage device characteristics. The goal is to minimize the number of clusters read from mass storage systems when subsets are requested. We emphasize in this paper proposed enhancements to current storage server protocols to permit control over physical placement of data on storage devices. We also discuss in some detail the aspects of the interface between the application programs and the mass storage system, as well as a workbench to help scientists to design the best reorganization of a dataset for anticipated access patterns.
Date: February 1, 1995
Creator: Chen, L.T.; Rotem, D.; Shoshani, A.; Drach, B.; Keating, M. & Louis, S.
Partner: UNT Libraries Government Documents Department