The Gardner and van Genuchten models of relativepermeability are widely used in analytical and numerical solutions toflow problems. However, the applicab ility of the Gardner model to realproblems is usually limited, because empirical relative permeability datato calibrate the model are not routinely available. In contrast, vanGenuchten parameters can be estimated using more routinely availablematric potential and saturation data. However, the van Genuchten model isnot amenable to analytical solutions. In this paper, we introducegeneralized conversion formulae that reconcile these two models. Ingeneral, we find that the Gardner parameter alpha G is related to the vanGenuchten parameters alpha vG and n by alpha G=alpha vG ~; 1:3 n. Thisconversion rule will allow direct recasting of Gardner-based analyticalsolutions in the van Genuchten parameter space. The validity of theproposed formulae was tested by comparing the predicted relativepermeability of various porous media with measured values.

Some of the ramifications of user needs, user satisfaction, and the survey as a shaper of library policy are discussed. The presentation is in three parts: philosophical thinking on user needs and satisfaction, a modest tutorial on survey methodology, and a brief review of the Sandia National Laboratory Technical Library's use of surveys for information gathering and decision making. (RWR)

Scaling studies for a SITEX negative ion source to produce 200-keV, 10-A, long pulse D/sup -/ beams are under way at Oak Ridge National Laboratory (ORNL). Designs have been restricted to the use of established techniques and reasonably well-demonstrated scaling. The results show that the 1-A SITEX source can be directly scaled to produce 200-keV, 10-A long pulse ion beams with a source power efficiency of less than or equal to 5 kW of total plasma generator power per ampere of D/sup -/ beam generated. Extracted electron-to-D/sup -/ ratios should be less than or equal to 0.06, with all extracted electrons recovered at less than or equal to 10% of the first gap potential energy difference. The close-coupled accelerating structure will be 5 cm long and have five electrodes with 21 slits each, with a 50-kV/cm field in each gap.

The neutral beam development group at ORNL has designed, constructed, and shipped four 50-kV, 100-A sources to PPPL to be used for neutral beam heating of the confined plasma on the PDX tokamak. These sources have higher current capability than scaled-down sources, and they are required to run for 0.5 s as opposed to the 0.3-s requirement for PLT and ISX-B sources. Due to an innovative electrode design, these higher power sources met these requirements and achieved a higher transmission efficiency - 76% of the total input power on target vs 60% for the original ISX-B and modified PLT sources or 40% for the original PLT sources. As a consequence, a power of 2 MW of neutrals to the torus target was achieved; this is a record for measured neutral power and exceeds that of any other power source expected to be used on such advanced tokamaks as TFTR and D-III. A theoretical consideration of the relevant Poisson-Vlasov equations for ions extracted from a plasma was used to optimize the ion optics. Using the same electrode design with a tetraode accelerating structure and a new, indirectly heated cathode, repeatable long pulse, high energy conditions of 70 kV, 7 A, 8 …

The 150 keV neutral beam test facility provides for the testing and development of neutral beam injectors and beam systems of the class that will be needed for the Tokamak Fusion Test Reactor (TFTR) and The Next Step (TNS). The test facility can simulate a complete beam line injection system and can provide a wide range of experimental operating conditions. Herein is offered a general description of the facility's capabilities and a discussion of present system performance.

A technique is described for obtaining short exposure (approximately 8 ns) high resolution photomicrographs of electrically exploded bridges using a pulsed laser for bridge illumination and band-pass filters to eliminate the intense self light. Two cameras are described, one for a small field of view (approximately 1 mm) and one for a relatively large field of view (approximately 20 mm). A carbon disulfide cell and a fiber-optic light guide are used to essentially eliminate speckle, which normally limits the resolution of laser photographs of diffuse surfaces. A series of photomicrographs showing the detailed burst characteristics of both flat and round bridges are shown.

Praxair, in conjunction with the Los Alamos National Laboratory, is developing a new technology, thermoacoustic heat engines and refrigerators, for liquefaction of natural gas. This is the only technology capable of producing refrigeration power at cryogenic temperatures with no moving parts. A prototype, with a projected natural gas liquefaction capacity of 500 gallons/day, has been built and tested. The power source is a natural gas burner. Systems will be developed with liquefaction capacities up to 10,000 to 20,000 gallons per day. The technology, the development project, accomplishments and applications are discussed. In February 2001 Praxair, Inc. purchased the acoustic heat engine and refrigeration development program from Chart Industries. Chart (formerly Cryenco, which Chart purchased in 1997) and Los Alamos had been working on the technology development program since 1994. The purchase included assets and intellectual property rights for thermoacoustically driven orifice pulse tube refrigerators (TADOPTR), a new and revolutionary Thermoacoustic Stirling Heat Engine (TASHE) technology, aspects of Orifice Pulse Tube Refrigeration (OPTR) and linear motor compressors as OPTR drivers. Praxair, in cooperation with Los Alamos National Laboratory (LANL), the licensor of the TADOPTR and TASHE patents, is continuing the development of TASHE-OPTR natural gas powered, natural gas liquefiers. The liquefaction …

The requirements for antenna design and phase control circuitry for a fast-wave current drive (FWCD) array operating in the ion cyclotron range of frequencies are considered. The design of a phase control system that can operate at arbitrary phasing over a wide range of plasma-loading and strap-coupling values is presented for a four-loop antenna array, prototypical of an array planned for the DIII-D tokamak (General Atomics, San Diego, California). The goal is to maximize the power launched with the proper polarization for current drive while maintaining external control of phase. Since it is desirable to demonstrate the feasibility of FWCD prior to ITER, a four-strap array has been designed for DIII-D to operate with the existing 2-MW transmitter at 60 MHz. 3 refs., 6 figs.

Valles Caldera No. 1 (VC-1) is the first Continental Scientific Drilling Program (CSDP) corehole drilled in the Valles caldera and the first continuously cored hole in the caldera region. The objectives of VC-1 were to penetrate a hydrothermal outflow plume near its source, to obtain structural and stratigraphic information near the intersection of the ring-fracture zone and the pre-caldera Jemez fault zone, and to core the youngest volcanic unit inside the caldera (Banco Bonito obsidian, 0.13 Ma). VC-1 penetrates 298 m of moat volcanics and caldera-fill ignimbrites, 35 m of pre-caldera volcaniclastic breccia, and 523 m of Paleozoic carbonates, sandstones and shales, with over 95% core recovery. Hydrothermal alterations are concentrated in sheared, brecciated and fractured zones from the volcaniclastic breccia to total depth with both the intensity and rank of alterations increasing with depth. Alterations consist primarily of clays, calcite, pyrite, quartz, and chlorite, but chalcopyrite has been identified as high as 518 m and molybdenite has been identified in a fractured zone at 847 m. Thermal aquifers were penetrated at various intervals from about 510 m on down. 11 refs., 5 figs.

A survey has been carried out for various potential structural safety problems of superconducting fusion magnets. These areas include: (1) Stresses due to inhomogeneous temperature distributions in magnets where normal regions have been initiated. (2) Stress distributions and yield forces due to cracks and failed regions. (3) Superconducting magnet response due to seismic excitation. These analyses have been carried out using a variety of large capacity finite element computer codes that allow for the evaluation of stresses in elastic or elastic-plastic zones and around singularities in the magnet structure. Thus far, these analyses have been carried out on UWMAK-I type magnet systems. (auth)

Two compact loop antennas have been designed to provide ion cyclotron resonant frequency (ICRF) heating for TFTR. The antennas can convey a total of 10 MW to accomplish core heating in either high-density or high-temperature plasmas. The near-term goal of heating TFTR plasmas and the longer-term goals of ease in handling (for remote maintenance) and high reliability (in an inaccessible tritium tokamak environment) were major considerations in the antenna designs. The compact loop configuration facilitates handling because the antennas fit completely through their ports. Conservative design and extensive testing were used to attain the reliability required for TFTR. This paper summarizes how these antennas will accomplish these goals. 5 figs, 1 tab.

We consider the electric dipole form factor, F{sub 3}(q{sup 2}), as well as the Dirac and Pauli form factors, F{sub 1}(q{sup 2}) and F{sub 2}(q{sup 2}), of the nucleon in the light-front formalism. We derive an exact formula for F{sub 3}(q{sup 2}) to complement those known for F{sub 1}(q{sup 2}) and F{sub 2}(q{sup 2}). We derive the light-front representation of the discrete symmetry transformations and show that time-reversal- and parity-odd effects are captured by phases in the light-front wave functions. We thus determine that the contributions to F{sub 2}(q{sup 2}) and F{sub 3}(q{sup 2}), Fock-state by Fock-state, are related, independent of the fundamental mechanism through which CP violation is generated. Our relation is not specific to the nucleon, but, rather, is true of spin-1/2 systems in general, be they lepton or baryon. The empirical values of the anomalous magnetic moments, in concert with empirical bounds on the associated electric dipole moments, can better constrain theories of CP violation. In particular, we find that the neutron and proton electric dipole moments echo the isospin structure of the anomalous magnetic moments, {kappa}{sup n} {approx} -{kappa}{sup p}.

The study of ecosystems is aided by representing structural and functional groups of organisms or processes as discrete components. A complex compartment model will explicitly map pathways from one compartment to another and specify transfer rates. This quantitative description allows insight into the dynamics of flow of nutrients, toxic chemicals, radionuclides, or energy. Three new indices that calculate compartment-specific probabilities of occurrence and recycling and illustrate the problem of applying these indices to ecosystem models are presented.

The ORNL RF Test Facility is to provide a national facility for the testing and evaluation of steady state, high-power (approx.1.0-MW) Ion Cyclotron Resonance Heating (ICRH) systems and components. The facility configuration consists of a vacuum vessel and two fully tested superconducting development magnets from the EBT-P program, arranged as a simple mirror of mirror ratio 4.8. The axial centerline distance between magnet throat centers is 112 cm. The vacuum vessel cavity has a large port (74 by 163 cm) and a test volume adequate for testing prototypic launchers for DIII-D and TFTR. The magnets are capable of generating a steady state field of approx.3 T on axis in the magnet throats. Steady state plasmas are generated in the facility by cyclotron resonance breakdown using a dedicated 200-kW, 28-GHz gyrotron. Rf sources are available covering a frequency range of 2 to 200 MHz at 1.5 kW and 3 to 18 MHz at 200 kW with several sources at intermediate parameters. Available in July 1986 will be a >1.0-MW, cw source spanning 40 to 80 MHz. The report consists of nine viewgraphs.

The rf Test Facility (RFTF) of Oak Ridge National Laboratory (ORNL) provides a national facility for the testing and evaluation of steady-state, high-power (approx.1.0-MW) ion cyclotron resonance heating (ICRH) systems and components. The facility consists of a vacuum vessel and two fully tested superconducting development magnets from the ELMO Bumpy Torus Proof-of-Principle (EBT-P) program. These are arranged as a simple mirror with a mirror ratio of 4.8. The axial centerline distance between magnet throat centers is 112 cm. The vacuum vessel cavity has a large port (74 by 163 cm) and a test volume adequate for testing prototypic launchers for Doublet III-D (DIII-D), Tore Supra, and the Tokamak Fusion Test Reactor (TFTR). Attached to the internal vessel walls are water-cooled panels for removing the injected rf power. The magnets are capable of generating a steady-state field of approx.3 T on axis in the magnet throats. Steady-state plasmas are generated in the facility by cyclotron resonance breakdown using a dedicated 200-kW, 28-GHz gyrotron. Available rf sources cover a frequency range of 2 to 200 MHz at 1.5 kW and 3 to 18 MHz at 200 kW, with several sources at intermediate parameters. Available in July 1986 will be a >1.0-MW, cw …

Initial ion cyclotron range of frequencies (ICRF) heating experiments on TFTR began in the summer of 1988. Although we were in the commissioning stage for much of the equipment, some plasma coupling measurements were made in the fall. This paper is focused on the results from the Bay L antenna. 3 refs., 3 figs., 1 tab.

The second phase (Hanna IVB) of a coal gasification experiment near Hanna, Wyoming, was completed in September 1979. The experiment attempted to link and gasify coal between process wells spaced 34.3 meters apart. Intermediate wells were positioned between the process wells so that the link could be relayed over shorter distances. Reverse combustion linking was attempted over a 22.9-meter and a 11.4-meter distance of the total well spacing. Thermal activity was generally noted in the upper 3 meters of the coal seam during the link. Two attempts to gasify over the 34.3-meter distance resulted in the propagation of the burn front at the coal overburden interface. Post-burn evaluation indicates fractures as major influencing factors of the combustion process. The Hanna IVB field test provided much insight into influence that geologic features have on in situ coal combustion. The influence of these faults, permeable zones, and cleats, on the air flow patterns can drastically change the overall results of a gasification experiment and should be studied further. The overall results of Hanna IVB were discouraging because of the rapid decline in the heating values for the production gas and the amount of coal gasified. With more complete geologic characerization prior to …

Coupling to plasma in the H-mode is essential to the success of future ignited machines such as CIT. To ascertain voltage and current requirements for high-power second harmonic heating (2 MW in a 35- by 50-cm port), coupling to the DIII-D tokamak with a prototype compact loop antenna has been measured. The results show good loading for L-mode and limiter plasmas, but coupling 2 MW to an H-mode plasma demands voltages and currents near the limit of present technology. We report the technological analysis and progress that allow coupling of these power densities. 5 refs., 4 figs.

The Booster synchrotron at Brookhaven National Laboratory has been incorporated into the accelerator chain at the Alternating Gradient Synchrotron (AGS) complex. After a successful first commissioning effort in the spring of 1991, the Booster has been part of this year's silicon, gold and proton physics runs. After a brief review of the Booster design goals, and of the early commissioning, this paper will summarize this year's activities.

Observations of high intensity effects on the proton performance of the AGS Booster are presented, including present operational limits and correction methods. The transverse emittances, optimum tune working points, damping of coherent transverse oscillations and correction of stopband resonances through third-order are discussed in addition to the observed tune spread due to space charge forces. The initial longitudinal phase space distribution, capture and acceleration parameters and measurements are also given. Operational tools and strategies relevant to the high intensity setup are mentioned.

A compact resonant loop antenna is installed on the ORNL Radio Frequency Test Facility (RFTF). Facility characteristics include a steady-state magnetic field of {approx} 0.5 T at the antenna, microwave-generated plasmas with n{sub e} {approx} 10{sup 12} cm{sup {minus}3} and T{sub e} {approx} 8 eV, and 100 kW of 25-MHz rf power. The antenna is tunable from {approximately}22--75 MHz, is designed to handle {ge}1 MW of rf power, and can be moved 5 cm with respect to the port flange. Antenna characteristics reported and discussed include the effect of magnetic field on rf voltage breakdown at the capacitor, the effects of magnetic field and plasma on rf voltage breakdown between the radiating element and the Faraday shield, the effects of graphite on Faraday shield losses, and the efficiency of coupling to the plasma. 2 refs., 4 figs.

Over the laqt decade, network practitioners have focused on monitoring, measuring, and characterizing traffic in the network to gain insight into building critical network components (from the protocol stack to routers and switches to network interface cards). Recent research shows that additional insight can be obtained by monitoring traffic at the application level (Le,, before application-sent traffic is modulated by the protocol stack) rather than in the network (i-e., after it is modulated by the protocol stack). Consequently, this paper describes a Monitor for Application-Generated Network Traffic (MAGNeT) that captures traffic generated by the application rather than traffic in the network. MAGNeT consists of application programs as well as modifications to the standard Linux kernel. Together, these tools provide the capability of monitoring an application's network behavior and protocol state information in production systems. The use of MAGNeT will enable the research community to construct a library of real traces of application-generated traffic from which researchers can more realistically test network protocol designs and theory. MAGNeT can also be used to verify the correct operation of protocol enhancements and to troubleshoot and tune protocol implementations.

The current trend in constructing high-performance computing systems is to connect a large number of machines via a fast interconnect or a large-scale network such as the Internet, This approach relies on the performance of the interconnect (or Internet) to enable Past, large-scale distributed computing. A detailed understanding of the communication traffic is required in order to optimize the operation of entire system. Network researchers traditionally monitor traffic in the network to gain the insight necessary to optimize network operations. Recent work suggests additional insight can be obtained by also monitoring trafflc at the application level. The Monitor for Application-Generated Network Traffic toolkit (MAGNeT) we describe here monitors application trallic patterns In production systems, thus enabling more highly optimized networks and interconnects for the next generation of high performance computing system. Keywords- monitor, measurement, network protocol, traffic characterization, TCP, MAGNet, traces, application-generated traffic, virtual supercomputing, network-aware applications, computational giids, high-perfomiance computing.

Future long-impulse magnetic fusion devices will have operating characteristics similar to those described in the design studies of the Tokamak Fusion Core Experiment (TFCX), the Fusion Engineering Device (FED), and the International Tokamak Reactor (INTOR). Their first-wall components (pumped limiters, divertor plates, and rf waveguide launchers with Faraday shields) will be subjected to intense bombardment by energetic particles exhausted from the plasma, including fusion products. These particles are expected to have particle energies of approx.100 eV, particle fluxes of approx.10/sup 18/ cm/sup -2/.s/sup -1/, and heat fluxes of approx.1 kW/cm/sup 2/ CW to approx.100 kW/cm/sup 2/ transient. No components are available to simultaneously handle these particle and heat fluxes, survive the resulting sputtering erosion, and remove exhaust gas without degrading plasma quality. Critical issues for research and development of first-wall components have been identified in the INTOR Activity. Test facilities are needed to qualify candidate materials and develop components. At Oak Ridge National Laboratory (ORNL), existing neutral beam and wave heating test facilities can be modified to simulate first-wall environments with heat fluxes up to 30 kW/cm/sup 2/, particle fluxes of approx.10/sup 18/ cm/sup -2/.s/sup -1/, and pulse lengths up to 30 s, within test volumes up to approx.100 L. …