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Sample records for mhd generator aerl mark vii

  1. MHD Power Generation

    ERIC Educational Resources Information Center

    Kantrowitz, Arthur; Rosa, Richard J.

    1975-01-01

    Explains the operation of the Magnetohydrodynamic (MHD) generator and advantages of the system over coal, oil or nuclear powered generators. Details the development of MHD generators in the United States and Soviet Union. (CP)

  2. Supersonic MHD generator system

    SciTech Connect

    Rahman, M.A.

    1983-11-29

    An improved MHD electrical power generating system of the type having a MHD topping cycle and a steam generating bottoming cycle is disclosed. The system typically includes a combustion system, a conventional MHD generator and a first diffuser radiant boiler. The improvement comprises a first supersonic MHD generator and ramjet engine configuration operatively connected in series with each other and with the conventional MHD generator. The first supersonic MHD generator and ramjet engine configuration increase the power output and improve the operating efficiency of the electrical generating system. A diffuser system is also disclosed which is in fluid communication with the supersonic MHD generator and the ramjet engine for collecting bypass plasma gas to be used for heating a second radiant boiler adapted for powering a steam turbine generator.

  3. MHD-generator-component development. Quarterly report, July 1980-September 1980

    SciTech Connect

    1980-12-01

    The overall objectives of this program are twofold: to contribute, by appropriate systematic experimental and analytical investigations, to the engineering database necessary for the design and construction of MHD generators at CDIF-scale (50 MW/sub th/) and baseload scale (2000 MW/sub th/), and to design and fabricate specific hardware items to be tested at the CDIF site in Butte, Montana. The overall program consists of a series of inter-related tasks, described as follows: (1) perform experimental investigations related to MHD channel design and performance by testing existing channel hardware and by fabricating and testing new channel hardware; (2) perform experimental investigations related to MHD channel perform and lifetime, with the principal aim of systematically obtaining data on the prototype electrodes for the coal-fired, subsonic, long-duration CDIF Generator 1B3; (3) perform testing on channel loading and control utilizing the supersonic Reference Channel No. 4 and other appropriate channels and/or test modules, at magnetic fields to 4 T; (4) provide for facility operation and maintenance of the Mk VI and Mk VII test bays; (5) design and fabricate the following items of CDIF hardware: CDIF Generator 1B2, CDIF Generator 1B3, CDIF 1B Ash Injection Combustor (AIC), CDIF Generator 1A2, and diagonal current control and load consolidation for the 1A2, 1B2 and 1B3 generators; and (4) compare the performance and durability characteristics of coal-fired versus (Mk VI-type) AIC-fired supersonic channels, using existing facilities at the AERL Haverhill site. Progress is described. (WHK)

  4. Explosive MHD Generators

    NASA Astrophysics Data System (ADS)

    Lebedev, E. F.; Ostashev, V. E.; Fortov, V. E.

    2004-11-01

    Explosive driven MHD generators (EMHD) occupy an intermediate position between destroyed Explosive Flux Compression Generators and solid-propellant- pulsed MHD generators. Studies revealed the negative consequences of destroying a plasma liner through Rayleigh-Taylor instability. The real efficiency of conversion of condensed HE charge chemical energy reaches ~10% if the magnetic field in a MHD channel is approximately 8-10 T. Accommodation of 20-30 linear MHD channels into a toroidal magnet seems to be optimal for EMHD generator design. This device may operate repeatedly with a frequency of up to 6.5×103pps.

  5. Disk MHD generator study

    NASA Technical Reports Server (NTRS)

    Retallick, F. D.

    1980-01-01

    Directly-fired, separately-fired, and oxygen-augmented MHD power plants incorporating a disk geometry for the MHD generator were studied. The base parameters defined for four near-optimum-performance MHD steam power systems of various types are presented. The finally selected systems consisted of (1) two directly fired cases, one at 1920 K (2996F) preheat and the other at 1650 K (2500 F) preheat, (2) a separately-fired case where the air is preheated to the same level as the higher temperature directly-fired cases, and (3) an oxygen augmented case with the same generator inlet temperature of 2839 (4650F) as the high temperature directly-fired and separately-fired cases. Supersonic Mach numbers at the generator inlet, gas inlet swirl, and constant Hall field operation were specified based on disk generator optimization. System pressures were based on optimization of MHD net power. Supercritical reheat stream plants were used in all cases. Open and closed cycle component costs are summarized and compared.

  6. Solar driven liquid metal MHD power generator

    NASA Technical Reports Server (NTRS)

    Lee, J. H.; Hohl, F. (Inventor)

    1983-01-01

    A solar energy collector focuses solar energy onto a solar oven which is attached to a mixer which in turn is attached to the channel of a MHD generator. Gas enters the oven and a liquid metal enters the mixer. The gas/liquid metal mixture is heated by the collected solar energy and moves through the MHD generator thereby generating electrical power. The mixture is then separated and recycled.

  7. Design Study: Rocket Based MHD Generator

    NASA Technical Reports Server (NTRS)

    1997-01-01

    This report addresses the technical feasibility and design of a rocket based MHD generator using a sub-scale LOx/RP rocket motor. The design study was constrained by assuming the generator must function within the performance and structural limits of an existing magnet and by assuming realistic limits on (1) the axial electric field, (2) the Hall parameter, (3) current density, and (4) heat flux (given the criteria of heat sink operation). The major results of the work are summarized as follows: (1) A Faraday type of generator with rectangular cross section is designed to operate with a combustor pressure of 300 psi. Based on a magnetic field strength of 1.5 Tesla, the electrical power output from this generator is estimated to be 54.2 KW with potassium seed (weight fraction 3.74%) and 92 KW with cesium seed (weight fraction 9.66%). The former corresponds to a enthalpy extraction ratio of 2.36% while that for the latter is 4.16%; (2) A conceptual design of the Faraday MHD channel is proposed, based on a maximum operating time of 10 to 15 seconds. This concept utilizes a phenolic back wall for inserting the electrodes and inter-electrode insulators. Copper electrode and aluminum oxide insulator are suggested for this channel; and (3) A testing configuration for the sub-scale rocket based MHD system is proposed. An estimate of performance of an ideal rocket based MHD accelerator is performed. With a current density constraint of 5 Amps/cm(exp 2) and a conductivity of 30 Siemens/m, the push power density can be 250, 431, and 750 MW/m(sup 3) when the induced voltage uB have values of 5, 10, and 15 KV/m, respectively.

  8. Computer Controlled MHD Power Consolidation and Pulse Generation System

    DTIC Science & Technology

    2007-11-02

    4465 Publication Date: Aug 01,1990 Title: Computer Controlled MHD Power Consolidation and Pulse Generation System Personal Author: Johnson, R...of Copies In Library: 000001 Record ID: 26725 : Computer Controlled MHD Power Consolidation and Pulse Generation System Final Technical Progress...Four-pulse CI System For A Diagonally Connected MHD Generator 14 9 Diagonal Output Voltage for Rsource =10 ohms, Rload = 1 ohm 16 10 Diagonal

  9. Performance of Combustion Disk MHD Generators.

    NASA Astrophysics Data System (ADS)

    Jenkins, Marion Karl

    of Hall fields were investigated using external voltage augmentation, and electric fields of 9 KV/m were observed in the channel with no evidence of breakdown. The analytical work consisted of the development of a two-dimensional computer program to predict boundary layer phenomena in disk generators, including the effects of turbulence, variable gas properties and MHD interaction. The numerical results show the effect of the variable MHD body force across the insulating wall boundary layer, giving rise to boundary layer velocities higher than those in the core. This leads to greater skin friction and heat transfer losses than what would be predicted with a quasi -one dimensional model. Calculations carried out for baseload -sized generators show the expected dependence of boundary layer behavior on channel operating conditions such as wall temperature, swirl, magnetic field strength and channel loading.

  10. Laser-powered MHD generators for space application

    NASA Technical Reports Server (NTRS)

    Jalufka, N. W.

    1986-01-01

    Magnetohydrodynamic (MHD) energy conversion systems of the pulsed laser-supported detonation (LSD) wave, plasma MHD, and liquid-metal MHD (LMMHD) types are assessed for their potential as space-based laser-to-electrical power converters. These systems offer several advantages as energy converters relative to the present chemical, nuclear, and solar devices, including high conversion efficiency, simple design, high-temperature operation, high power density, and high reliability. Of these systems, the Brayton cycle liquid-metal MHD system appears to be the most attractive. The LMMHD technology base is well established for terrestrial applications, particularly with regard to the generator, mixer, and other system components. However, further research is required to extend this technology base to space applications and to establish the technology required to couple the laser energy into the system most efficiently. Continued research on each of the three system types is recommended.

  11. MHD generator component development. Quarterly report, July 1983-September 1983

    SciTech Connect

    Not Available

    1983-11-01

    The overall objectives of this program are two-fold: (1) To contribute, by appropriate systematic experimental and analytical investigations, to the engineering data base necessary for the design and construction of MHD generators at CDIF-scale (50 MW/sub th/) and baseload scale (2000 MW/sub th/). (2) To design and fabricate specific hardware items to be tested at the CDIF site in Butte, Montana. The program consists of a series of related tasks: (1) MHD channel design and performance; (2) MHD channel construction and lifetime; (3) MHD channel loading and control; (4) facility operation; (5) CDIF related hardware; and (6) high interaction tests of a supersonic channel. Progress is reported. (WHK)

  12. Performance evaluations of MHD generator tests at CDIF

    NASA Astrophysics Data System (ADS)

    Daniel, V. W.; Lineberry, J. T.; Wu, Y. C. L.

    1992-01-01

    Experimental data from CDIF coal-fired MHD generator test 90-DIAG-3 are analyzed. The results of two independent studies are presented and compared. Both studies impose experimental data upon modeling to derive information on plasma properties and electrical loss mechanisms. The first technique applies routine electrical data to special solutions of the MHD electrical equations to determine gross electrophysical properties and nonuniformity parameters of the generator medium (plasma plus slag) over one pitch control volumes along the length of the MHD channel. The second technique pits a predictive 1D MHD generator model against input experimental Hall voltage data. The generator model solves for the MHD plasmadynamic and electrical processes required to fit the experimental voltage distribution to determine plasma properties with wall and electrical losses. Among the parameters that are estimated by these methods are conductivity, Hall parameter, interelectrode resistances, and the plasma nonuniformity factors (e.g., G). The magnitude of leakage current (slag or otherwise) can also inferred from these analyses.

  13. Performance enhancement of explosive-driven MHD generators

    SciTech Connect

    Smith, I.R.; Senior, P.; Stewardson, H.R.; Vadher, V.V. . Dept. of Electronic and Electrical Engineering); Novac, B.M. )

    1994-11-01

    The change in the circuit inductance of a pulsed MHD generator as the plasma sheet travels along the electrodes acts to increase the voltage produced in the generator. The paper explains how unconventional electrode arrangements enable this effect to be significantly magnified, thereby bringing about a considerable increase in the output that can be obtained.

  14. MHD marking using the MSE polarimeter optics in ILW JET plasmas.

    PubMed

    Reyes Cortes, S; Alper, B; Alves, D; Baruzzo, M; Bernardo, J; Buratti, P; Coelho, R; Challis, C; Chapman, I; Hawkes, N; Hender, T C; Hobirk, J; Joffrin, E

    2016-11-01

    In this communication we propose a novel diagnostic technique, which uses the collection optics of the JET Motional Stark Effect (MSE) diagnostic, to perform polarimetry marking of observed MHD in high temperature plasma regimes. To introduce the technique, first we will present measurements of the coherence between MSE polarimeter, electron cyclotron emission, and Mirnov coil signals aiming to show the feasibility of the method. The next step consists of measuring the amplitude fluctuation of the raw MSE polarimeter signals, for each MSE channel, following carefully the MHD frequency on Mirnov coil data spectrograms. A variety of experimental examples in JET ITER-Like Wall (ILW) plasmas are presented, providing an adequate picture and interpretation for the MSE optics polarimeter technique.

  15. MHD marking using the MSE polarimeter optics in ILW JET plasmas

    NASA Astrophysics Data System (ADS)

    Reyes Cortes, S.; Alper, B.; Alves, D.; Baruzzo, M.; Bernardo, J.; Buratti, P.; Coelho, R.; Challis, C.; Chapman, I.; Hawkes, N.; Hender, T. C.; Hobirk, J.; Joffrin, E.

    2016-11-01

    In this communication we propose a novel diagnostic technique, which uses the collection optics of the JET Motional Stark Effect (MSE) diagnostic, to perform polarimetry marking of observed MHD in high temperature plasma regimes. To introduce the technique, first we will present measurements of the coherence between MSE polarimeter, electron cyclotron emission, and Mirnov coil signals aiming to show the feasibility of the method. The next step consists of measuring the amplitude fluctuation of the raw MSE polarimeter signals, for each MSE channel, following carefully the MHD frequency on Mirnov coil data spectrograms. A variety of experimental examples in JET ITER-Like Wall (ILW) plasmas are presented, providing an adequate picture and interpretation for the MSE optics polarimeter technique.

  16. Characterization of open-cycle coal-fired MHD generators

    NASA Astrophysics Data System (ADS)

    Wormhoudt, J.; Yousefian, V.; Weinberg, M.; Kolb, C.; Martinez-Sanchez, M.; Cheng, W.; Bien, F.; Dvore, D.; Unkel, W.; Stewart, G.

    1980-09-01

    The successful design of full-scale, open-cycle, coal-fired MHD generators for baseload electrical production requires a detailed understanding of the plasma chemical and plasma dynamic characteristics of anticipated combustor and channel fluids. Progress in efforts to model the efficiency of an open-cycle, coal-fired MHD channel based on the characterization of the channel flow as well as laboratory experiments to validate the modeling effort is detailed. In addition, studies related to understanding arcing phenomena in the vicinity of an anode are reported.

  17. RANDOM PULSE GENERATOR PRODUCING FIDUCIAL MARKS

    DOEpatents

    Nielsen, W.F.

    1960-02-01

    The apparatus for automatically applying a fiducial marking, having a nonrepetitive pattern, to a plurality of simultaneously made records comprises, in series, a bypass filter, a trigger circuit, and a pulse generator, with printing means connected to and controlled by the pulse generator for simultaneously making the visible fiducial marks on a plurality of simultaneously produced records.

  18. Three-dimensional analysis of MHD generators and diffusers

    SciTech Connect

    Vanka, S P; Ahluwalia, R K; Doss, E D

    1982-03-01

    The three-dimensional flow and heat transfer phenomena in MHD channels and diffusers are analyzed by solving the governing partial differential equations for flow and electrical fields. The equation set consists of the mass continuity equation, the three momentum equations, the equations for enthalpy, turbulence kinetic energy and its dissipation rate, and the Maxwell equations. This set of coupled equations is solved by the use of a finite-difference calculation procedure. The turbulence is represented by a two-equation model of turbulence in which partial differential equations are solved for the turbulence kinetic energy and its dissipation rate. Calculations have been performed for Faraday and diagonally-connected channels. Specifically, the AEDC (Faraday) and the UTSI (diagonal) channels have been analyzed, and the results are compared with experimental data. The agreement is fairly good for all the measured quantities. The effects of channel loading on the three-dimensional flow characteristics of Faraday and diagonally-connected generators have been also analyzed. A simple argument is presented to show qualitatively the role of MHD body forces in generating axial vorticity and hence secondary flows in the cross-stream. Calculations have also been made to study the flow evolution in MHD diffusers. The calculations show that the velocity overshoots and secondary flows decay along the diffusers length. Plots of velocity, skin friction and pressure recovery are presented to illustrate the flow development in MHD diffusers.

  19. Solar-Driven Liquid-Metal MHD Generator

    NASA Technical Reports Server (NTRS)

    Hohl, F.; Lee, J. H.

    1982-01-01

    Liquid-metal magnetohydrodynamic (MHD) power generator with solar oven as its heat source has potential to produce electric power in space and on Earth at high efficiency. Generator focuses radiation from Sun to heat driving gas that pushes liquid metal past magnetic coil. Power is extracted directly from electric currents set up in conducting liquid. Using solar energy as fuel can save considerable costs and payload weight, compared to previous systems.

  20. Current distribution and nonuniformity effects in MHD disk generators

    NASA Astrophysics Data System (ADS)

    Roseman, D. F.

    1982-08-01

    Current distribution and nonuniformity effects in combustion driven MHD disk generators were studied. The importance of these phenomena to baseload power generation was investigated. The peg wall construction allowed current and voltage distributions to be measured. The channel was operated with plasma temperatures up to 2750 K and magnetic field strengths up to 5.5 Tesla. The magnitudes of the currents and voltages were reduced by significant loss mechanisms, primarily electrode losses and current leakage through the wall caused by potassium seed penetration of the castable ceramic between the pegs. A simple circuit model accounting for these losses was developed to be compared with analytical calculations. Under normal uniform electrical loading the distributions measured in the channel were uniform as expected. Nonuniform electrical loading was used to produce and measure effects on the current distribution that occur only in the presence of high magnetic fields as required for MHD power generation.

  1. Space-based laser-driven MHD generator: Feasibility study

    NASA Technical Reports Server (NTRS)

    Choi, S. H.

    1986-01-01

    The feasibility of a laser-driven MHD generator, as a candidate receiver for a space-based laser power transmission system, was investigated. On the basis of reasonable parameters obtained in the literature, a model of the laser-driven MHD generator was developed with the assumptions of a steady, turbulent, two-dimensional flow. These assumptions were based on the continuous and steady generation of plasmas by the exposure of the continuous wave laser beam thus inducing a steady back pressure that enables the medium to flow steadily. The model considered here took the turbulent nature of plasmas into account in the two-dimensional geometry of the generator. For these conditions with the plasma parameters defining the thermal conductivity, viscosity, electrical conductivity for the plasma flow, a generator efficiency of 53.3% was calculated. If turbulent effects and nonequilibrium ionization are taken into account, the efficiency is 43.2%. The study shows that the laser-driven MHD system has potential as a laser power receiver for space applications because of its high energy conversion efficiency, high energy density and relatively simple mechanism as compared to other energy conversion cycles.

  2. International Conference on MHD Electrical Power Generation, 7th, Massachusetts Institute of Technology, Cambridge, MA, June 16-20, 1980, Proceedings. Volumes 1, 2 & 3

    NASA Astrophysics Data System (ADS)

    Dawson, A. M.; Overlan, D.

    The first volume of this conference on magnetohydrodynamics (MHD) for electrical power generation covers: (1) MHD pilot plants; (2) MHD generator experiments and modeling; (3) the performance of various MHD generator types; (4) MHD channel design considerations; (5) MHD channel materials considerations; (6) MHD system components, heat recovery and emissions; and (7) MHD oxidizers and inverters. The second volume deals with (8) MHD system magnets and combustors; (9) MHD field, flow and chemical processes; (10) MHD fluid dynamics; (11) MHD electrical power plant design; (12) current transfer and diagnostics; and (13) MHD power plant systems considerations.

  3. MHD generator of electrical energy working on the gasification products of lignites

    NASA Astrophysics Data System (ADS)

    Derevianko, V. A.; Slavin, V. S.; Sokolov, V. S.

    1981-03-01

    An investigation is presented of an MHD generator of electrical energy fueled by gasification products of lignite coals using the T-layer effect which eliminates caustic additives. A quasi-one-dimensional theory of linear MHD processes is constructed on the basis of MHD equations; a design of an industrial generator is discussed.

  4. High-magnetic-field MHD-generator program

    NASA Astrophysics Data System (ADS)

    Kruger, C. H.; Eustis, R. H.; Mitchner, M.; Self, S. A.; Koester, J. K.; Nakamura, T.

    1981-04-01

    Channel phenomena which are important at high magnetic fields are investigated. Nonuniformity effects, boundary layers, hall field breakdown, the effects of electrode configuration and current concentrations, and studies of steady state combustion disk and linear channels in a 6 Tesla magnet of small dimensions were studied. A multi-channel fiber optics diagnostic system is described. A one dimensional model to describe the performance of a non-ideal MHD generator was developed. A two dimensional MHD computer code was developed which predicts the dependence on electrode and insulator dimensions of the onset of interelectrode Hall field breakdown. Calculations of the effects of nonuniformities on the flow and electrical behavior of baseload-sized disk generators were performed.

  5. Off-design performance analysis of MHD generator channels

    NASA Astrophysics Data System (ADS)

    Wilson, D. R.; Williams, T. S.

    1980-01-01

    A computer code for performing parametric design point calculations, and evaluating the off-design performance of MHD generators has been developed. The program is capable of analyzing Faraday, Hall, and DCW channels, including the effect of electrical shorting in the gas boundary layers and coal slag layers. Direct integration of the electrode voltage drops is included. The program can be run in either the design or off-design mode. Details of the computer code, together with results of a study of the design and off-design performance of the proposed ETF MHD generator are presented. Design point variations of pre-heat and stoichiometry were analyzed. The off-design study included variations in mass flow rate and oxygen enrichment.

  6. MHD generator with improved network coupling electrodes to a load

    DOEpatents

    Rosa, Richard J.

    1977-01-01

    An MHD generator has a plurality of segmented electrodes extending longitudinally of a duct, whereby progressively increasing high DC voltages are derived from a set of cathode electrodes and progressively increasing low DC voltages are derived from a set of anode electrodes. First and second load terminals are respectively connected to the cathode and anode electrodes by separate coupling networks, each of which includes a number of SCR's and a number of diode rectifiers.

  7. Liquid-metal-piston MHD generator

    NASA Technical Reports Server (NTRS)

    Palmer, J. P.

    1969-01-01

    Magnetohydrodynamic generator uses a slug or piston of liquid potassium as the working fluid. An expanding vapor of the metal is allowed to reciprocate the liquid-metal-piston through a magnetic field and the expansion energy is converted directly into electrical energy.

  8. Plasma plume MHD power generator and method

    DOEpatents

    Hammer, James H.

    1993-01-01

    Highly-conducting plasma plumes are ejected across the interplanetary magnetic field from a situs that is moving relative to the solar wind, such as a spacecraft or an astral body, such as the moon, having no magnetosphere that excludes the solar wind. Discrete plasma plumes are generated by plasma guns at the situs extending in opposite directions to one another and at an angle, preferably orthogonal, to the magnetic field direction of the solar wind plasma. The opposed plumes are separately electrically connected to their source by a low impedance connection. The relative movement between the plasma plumes and the solar wind plasma creates a voltage drop across the plumes which is tapped by placing the desired electrical load between the electrical connections of the plumes to their sources. A portion of the energy produced may be used in generating the plasma plumes for sustained operation.

  9. Transpiration cooled electrodes and insulators for MHD generators

    DOEpatents

    Hoover, Jr., Delmer Q.

    1981-01-01

    Systems for cooling the inner duct walls in a magnetohydrodynamic (MHD) generator. The inner face components, adjacent the plasma, are formed of a porous material known as a transpiration material. Selected cooling gases are transpired through the duct walls, including electrically insulating and electrode segments, and into the plasma. A wide variety of structural materials and coolant gases at selected temperatures and pressures can be utilized and the gases can be drawn from the generation system compressor, the surrounding environment, and combustion and seed treatment products otherwise discharged, among many other sources. The conduits conducting the cooling gas are electrically insulated through low pressure bushings and connectors so as to electrically isolate the generator duct from the ground.

  10. Effects of water molecules of Ar-Cs MHD disk generator operated with strong MHD interaction

    SciTech Connect

    Ishikawa, M.; Kosugi, A.; Inui, Y.; Kabashima, S.

    1998-07-01

    Effects of water molecule impurity are studied on performance of a disk type MHD generator operated with Ar-Cs weakly ionized plasma. To reveal phenomena for a wide range of operation conditions, time-dependent one-dimensional analyses are carried out, where an up-wind, second order Chakravarthy TVD scheme is applied for the gasdynamics, while a Galerkin FEM is used for the electrodynamics. A simplified model is used for the water molecule impurity, where total effects of nonelastic collision between electrons and water molecules are estimated by the collision loss factor of electrons and also the electron momentum-transfer collision frequency is taken into account. The collision loss factor of electrons and the electron momentum-transfer collision frequency are taken from references, and the loss factor is assumed to be 700 independently of the electron temperature. On the Fuji-1 facilities at Tokyo Institute Technology, Japan, series of experiment A4105 were carried out with the Disk F-4 generator. Ar was heated with the heat-exchanger heated by the natural gas-air combustion and the metal cesium was used as the seeding material, while SCM maintained the magnetic field of 4.7 T at the center of disk and the very strong MHD interaction was realized. The thermal input was about 3 MW, the electrical output was about 500 kW with the enthalpy extraction ratio of about 17%. The numerical analyses have shown that the water molecule enhances the ionization instability at the low voltage loading because of insufficient Joule heating for electrons. The generator performance is degraded and the strong MHD interaction between the unstable plasma and the flow field induces slow and fast moving shock waves, leading to the very complicated flow field. The fast and slow moving shocks collide with each other, merge into a sharp shock moving downward, and then the shock front moves back slightly to maintain the pressure balance, collides again with another weak moving shock, and

  11. Design of closed-cycle MHD generator with nonequilibrium ionization and system

    NASA Technical Reports Server (NTRS)

    Voshall, R. E.; Wright, R. J.; Liebermann, R. W.

    1977-01-01

    A method is developed to include the nonequilibrium ionization process in the MHD generator duct design equations, and these equations are coupled to the thermodynamic conditions of the closed cycle system. This is used to relate MHD generator size, configuration and gas conditions to the overall thermodynamic efficiency of the system. The system studied consists of an MHD loop (Ar + Cs or He + Cs) topping a steam bottoming plant.

  12. Assessment of disk MHD generators for a base load powerplant

    NASA Technical Reports Server (NTRS)

    Chubb, D. L.; Retallick, F. D.; Lu, C. L.; Stella, M.; Teare, J. D.; Loubsky, W. J.; Louis, J. F.; Misra, B.

    1981-01-01

    Results from a study of the disk MHD generator are presented. Both open and closed cycle disk systems were investigated. Costing of the open cycle disk components (nozzle, channel, diffuser, radiant boiler, magnet and power management) was done. However, no detailed costing was done for the closed cycle systems. Preliminary plant design for the open cycle systems was also completed. Based on the system study results, an economic assessment of the open cycle systems is presented. Costs of the open cycle disk conponents are less than comparable linear generator components. Also, costs of electricity for the open cycle disk systems are competitive with comparable linear systems. Advantages of the disk design simplicity are considered. Improvements in the channel availability or a reduction in the channel lifetime requirement are possible as a result of the disk design.

  13. Two-dimensional MHD generator model. [GEN code

    SciTech Connect

    Geyer, H. K.; Ahluwalia, R. K.; Doss, E. D.

    1980-09-01

    A steady state, two-dimensional MHD generator code, GEN, is presented. The code solves the equations of conservation of mass, momentum, and energy, using a Von Mises transformation and a local linearization of the equations. By splitting the source terms into a part proportional to the axial pressure gradient and a part independent of the gradient, the pressure distribution along the channel is easily obtained to satisfy various criteria. Thus, the code can run effectively in both design modes, where the channel geometry is determined, and analysis modes, where the geometry is previously known. The code also employs a mixing length concept for turbulent flows, Cebeci and Chang's wall roughness model, and an extension of that model to the effective thermal diffusities. Results on code validation, as well as comparisons of skin friction and Stanton number calculations with experimental results, are presented.

  14. Electrode materials for coal-fired MHD generators

    NASA Astrophysics Data System (ADS)

    Perkins, R. A.

    1980-10-01

    Metallic materials are evaluated as electrodes for coal fired MHD generators. A laboratory test that simulates the electrochemical and corrosive environment was developed and used to characterize electrode behavior in a diffuse current flow (nonarcing) mode of operation. High current density requires that an electron transport mechanism of current flow be maintained. With inert, stable electrodes, anode polarization occurs and ionic conduction prevails, limiting current to low values. The nature of this behavior and approaches to overcoming anodic polarization are studied as a function of electrode material, slag composition, and temperature. By operating at high temperatures and with controlled slag chemistries to produce a very fluid slag, depolarization may be achieved by mechanical mixing. Interrupted current flow are required to aid in breaking down anodic polarization.

  15. Feasibility of the inflow disk generator for open-cycle MHD power generation

    NASA Astrophysics Data System (ADS)

    Nakamura, T.; Lear, W. E.; Eustis, R. H.

    1981-01-01

    A feasibility study of the inflow disk MHD generator for baseload applications was performed. Each design element, i.e., the combustor, the inlet flow path, the generator channel, the diffuser and the magnet, was studied in detail in order to provide a comprehensive assessment of the inflow disk generator. Based on these results, the performance of the inflow disk generator was calculated for two different thermal inputs: 1250 MW(th) and 2500 MW(th). It was shown that the performance of the inflow disk generator is similar to that of the diagonal generator within the uncertainty of the analysis.

  16. Computer controlled MHD power consolidation and pulse generation system

    SciTech Connect

    Johnson, R.; Marcotte, K.; Donnelly, M.

    1990-01-01

    The major goal of this research project is to establish the feasibility of a power conversion technology which will permit the direct synthesis of computer programmable pulse power. Feasibility has been established in this project by demonstration of direct synthesis of commercial frequency power by means of computer control. The power input to the conversion system is assumed to be a Faraday connected MHD generator which may be viewed as a multi-terminal dc source and is simulated for the purpose of this demonstration by a set of dc power supplies. This consolidation/inversion (CI), process will be referred to subsequently as Pulse Amplitude Synthesis and Control (PASC). A secondary goal is to deliver a controller subsystem consisting of a computer, software, and computer interface board which can serve as one of the building blocks for a possible phase II prototype system. This report period work summarizes the accomplishments and covers the high points of the two year project. 6 refs., 41 figs.

  17. Fundamental Studies On Development Of MHD (Magnetohydrodynamic) Generator Implement On Wave Energy Harvesting

    NASA Astrophysics Data System (ADS)

    Majid, M. F. M. A.; Apandi, Muhamad Al-Hakim Md; Sabri, M.; Shahril, K.

    2016-02-01

    As increasing of agricultural and industrial activities each year has led to an increasing in demand for energy. Possibility in the future, the country was not able to offer a lot of energy and power demand. This means that we need to focus on renewable energy to supply the demand for energy. Energy harvesting is among a method that can contribute on the renewable energy. MHD power generator is a new way to harvest the energy especially Ocean wave energy. An experimental investigation was conducted to explore performance of MHD generator. The effect of intensity of NaCl Solution (Sea Water), flow rate of NaCl solution, magnetic strength and magnet position to the current produce was analyzed. The result shows that each factor is give a significant effect to the current produce, because of that each factor need to consider on develop of MHD generator to harvest the wave energy as an alternative way to support the demand for energy.

  18. Slag condensation kinetics in the channel of an MHD generator: Explosive condensation

    SciTech Connect

    Zhukhovitskii, D.I.; Khrapak, A.G.; Yakubov, I.T.

    1983-09-01

    A study has been made of the bulk condensation of the inorganic part of combustion products in the channel of an MHD generator. An analytic solution has been obtained to the equations describing the process. A physical interpretation is given for the various stages. It is known that the condensation consists of several slightly overlapping stages. First there is the explosive formation of nuclei, which then grow rapidly, and a quasistationary stage of condensation sets in. A calculation is performed for particular conditions in an MHD generator.

  19. Closed cycle MHD generator with nonuniform gas-plasma flow driving recombinated plasma clots

    SciTech Connect

    Slavin, V.S.; Danilov, V.V.; Sokolov, V.S.

    1996-12-31

    A new concept of a closed cycle MHD generator without alkali seed has been suggested. The essence of it is the phenomenon of frozen conductivity for recombined plasma which appears for noble gas at T{sub e} > 4,000 K. At the inlet of the MHD channel in supersonic flow of noble gas (He or Ar) the plasma clots with electron density about 10{sup 15} cm{sup {minus}3} are formed by pulsed intense electron beam with energy about 300 keV. Gas flow drives these clots in a cross magnetic field along the MHD channel which has electrodes connected with the load by Faraday scheme. The gas flow pushes plasma layers and produces electric power at the expense of enthalpy extraction. The numerical simulation has shown that a supersonic gas flow, containing about 4 plasma layers in the MHD channel simultaneously, is braked without shock waves creation. This type of the MHD generator can provide more than 30% enthalpy extraction ratio and about 80% isentropic efficiency. The advantages of the new concept are the following: (a) possibility of working at higher pressure and lower temperature, (b) operation with alkali seed.

  20. Possible uses for Phillips Laboratory MHD generator. Final report, 1 October 1994-30 August 1995

    SciTech Connect

    Turchi, P.J.

    1995-08-01

    There is interest in electromagnetic energy sources for applications to directed energy weapons. Candidates include portable conventional rotating machinery electric generators, magnetic flux compression generators (aka explosive generators, magnetocumulative generators or MCGs) based on explosive action, and magnetohydrodynamic (MHD) generators using chemical energy of explosives or rocket propellants. For portable high energy MHD generators, US technology base appeared to need rescue. The US has received a MHD device in the PAMlR-3U, developed in the former Soviet Union. The present discussion considers uses of this generator for programs on high-power microwave systems and other directed energy concepts. Future applications will be limited by development and funding of specific technical needs. A useful next step would be detailed design of a system to charge high-voltage pulsers. This design should include comparison of single-pulse switching to achieve high-voltage from an inductive storage coil (energy storage option) vs repetitive switching at low voltage, followed by custom built transformers (direct drive option).

  1. Method of generating electricity using an endothermic coal gasifier and MHD generator

    DOEpatents

    Marchant, David D.; Lytle, John M.

    1982-01-01

    A system and method of generating electrical power wherein a mixture of carbonaceous material and water is heated to initiate and sustain the endothermic reaction of carbon and water thereby providing a gasified stream containing carbon monoxide, hydrogen and nitrogen and waste streams of hydrogen sulfide and ash. The gasified stream and an ionizing seed material and pressurized air from a preheater go to a burner for producing ionized combustion gases having a temperature of about 5000.degree. to about 6000.degree. F. which are accelerated to a velocity of about 1000 meters per second and passed through an MHD generator to generate DC power and thereafter through a diffuser to reduce the velocity. The gases from the diffuser go to an afterburner and from there in heat exchange relationship with the gasifier to provide heat to sustain the endothermic reaction of carbon and water and with the preheater to preheat the air prior to combustion with the gasified stream. Energy from the afterburner can also be used to energize other parts of the system.

  2. Coal-fired MHD combustor development project: Phase IIIB. First quarterly technical progress report, 13 January-30 April 1982

    SciTech Connect

    1982-05-20

    The first quarterly technical progress report of the Coal-Fired MHD Combustor Development Project (Phase IIIB) presents the accomplishments during the period 13 January to 30 April, 1982. The scope of work covered by this quarterly report relates to those tasks associated with preparing the TRW 20 MW/sub t/ MHD coal combustor for delivery to AERL for integrated power tests and the work associated with the preliminary design of a 50 MW/sub t/ coal-fired combustor. Progress during this reporting period is described. All new 20 MW/sub t/ hardware was designed and fabricated. Interface coordination meetings were conducted with AERL and DOE. Interface control drawings were completed and a 20 MW/sub t/ coal combustion User's manual was delivered to AERL. The User's manual contained a shipping plan, a crew training plan, an assembly manual, interface documentation and recommended operating procedures. Facility/combustor set-up was completed and the pre-delivery 20 MW/sub t/ coal combustor qualification test series was completed. The 50 MW/sub t/ coal-fired MHD combustor preliminary designs were finalized and the DOE preliminary design review (PDR) was successfully completed.

  3. Design study of superconducting magnets for a combustion magnetohydrodynamic (MHD) generator

    NASA Technical Reports Server (NTRS)

    Thome, R. J.; Ayers, J. W.

    1977-01-01

    Design trade off studies for 13 different superconducting magnet systems were carried out. Based on these results, preliminary design characteristics were prepared for several superconducting magnet systems suitable for use with a combustion driven MHD generator. Each magnet generates a field level of 8 T in a volume 1.524 m (60 in.) long with a cross section 0.254 m x 0.254 m (10 in. x 10 in.) at the inlet and 0.406 m x .406 m (16 in. x 16 in.) at the outlet. The first design involves a racetrack coil geometry intended for operation at 4.2 K; the second design uses a racetrack geometry at 2.0 K; and the third design utilizes a rectangular saddle geometry at 4.2 K. Each case was oriented differently in terms of MHD channel axis and main field direction relative to gravity in order to evaluate fabrication ease. All cases were designed such that the system could be disassembled to allow for alteration of field gradient in the MHD channel by changing the angle between coils. Preliminary design characteristics and assembly drawings were generated for each case.

  4. ORNL Resolved Resonance Covariance Generation for ENDF/B-VII.1

    SciTech Connect

    Leal, L.; Guber, K.; Wiarda, D.; Arbanas, G.; Derrien, H.; Sayer, R.; Larson, N.; Dunn, M.

    2012-12-15

    Resonance-parameter covariance matrix (RPCM) evaluations in the resolved resonance regionwere done at the Oak Ridge National Laboratory (ORNL) for the chromium isotopes, titanium isotopes, {sup 19}F, {sup 58}Ni, {sup 60}Ni, {sup 35}Cl, {sup 37}Cl, {sup 39}K, {sup 41}K, {sup 55}Mn, {sup 233}U, {sup 235}U, {sup 238}U, and {sup 239}Pu using the computer code SAMMY. The retroactive approach of the code SAMMY was used to generate the RPCMs for {sup 233}U. For {sup 235}U, the approach used for covariance generation was similar to the retroactive approach with the distinction that real experimental data were used as opposed to data generated from the resonance parameters. RPCMs for {sup 238}U and {sup 239}Pu were generated together with the resonance parameter evaluations. The RPCMs were then converted in the ENDF format using the FILE32 representation. Alternatively, for computer storage reasons, the FILE32 was converted in the FILE33 cross section covariance matrix (CSCM). Both representations were processed using the computer code PUFF-IV. This paper describes the procedures used to generate the RPCM and CSCM in the resonance region for ENDF/B-VII.1. The impact of data uncertainty in nuclear reactor benchmark calculations is also presented.

  5. ORNL Resolved Resonance Covariance Generation for ENDF/B-VII.1

    SciTech Connect

    Leal, Luiz C.; Guber, Klaus H.; Wiarda, Dorothea; Arbanas, Goran; Derrien, Herve; Sayer, Royce O.; Larson, Nancy M.; Dunn, Michael E.

    2012-12-01

    Resonance-parameter covariance matrix (RPCM) evaluations in the resolved resonance regionwere done at the Oak Ridge National Laboratory (ORNL) for the chromium isotopes, titanium isotopes, 19F, 58Ni, 60Ni, 35Cl, 37Cl, 39K, 41K, 55Mn, 233U, 235U, 238U, and 239Pu using the computer code SAMMY. The retroactive approach of the code SAMMY was used to generate the RPCMs for 233U. For 235U, the approach used for covariance generation was similar to the retroactive approach with the distinction that real experimental data were used as opposed to data generated from the resonance parameters. RPCMs for 238U and 239Pu were generated together with the resonance parameter evaluations. The RPCMs were then converted in the ENDF format using the FILE32 representation. Alternatively, for computer storage reasons, the FILE32 was converted in the FILE33 cross section covariance matrix (CSCM). Both representations were processed using the computer code PUFF-IV. This paper describes the procedures used to generate the RPCM and CSCM in the resonance region for ENDF/B-VII.1. The impact of data uncertainty in nuclear reactor benchmark calculations is also presented.

  6. 3-D General Relativistic MHD Simulations of Generating Jets

    NASA Astrophysics Data System (ADS)

    Nishikawa, K.-I.; Koide, S.; Shibata, K.; Kudoh, T.; Frank, J.; Sol, H.

    1999-12-01

    We have investigated the dynamics of an accretion disk around Schwarzschild black holes initially threaded by a uniform poloidal magnetic field in a non-rotating corona (either in a steady-state infalling state or in hydrostatic equilibrium) around a non-rotating black hole using a 3-D GRMHD with the ``axisymmetry'' along the z-direction. Magnetic field is tightly twisted by the rotation of the disk, and plasmas in the shocked region of the disk are accelerated by J x B force to form bipolar relativistic jets. In order to investigate variabilities of generated relativistic jets and magnetic field structure inside jets, we have performed calculations using the 3-D GRMHD code with a full 3-dimensional system. We will investigate how the third dimension affects the global disk dynamics and jet generation.

  7. 3-D General Relativistic MHD Simulations of Generating Jets

    NASA Astrophysics Data System (ADS)

    Nishikawa, K.-I.; Koide, S.; Shibata, K.; Kudoh, T.; Sol, H.; Hughes, J. P.

    2001-12-01

    We have investigated the dynamics of an accretion disk around Schwarzschild black holes initially threaded by a uniform poloidal magnetic field in a non-rotating corona (either in a steady-state infalling state) around a non-rotating black hole using a 3-D GRMHD with the ``axisymmetry'' along the z-direction. Magnetic field is tightly twisted by the rotation of the disk, and plasmas in the shocked region of the disk are accelerated by J x B force to form bipolar relativistic jets. In order to investigate variabilities of generated relativistic jets and magnetic field structure inside jets, we have performed calculations using the 3-D GRMHD code with a full 3-dimensional system without the axisymmetry. We have investigated how the third dimension affects the global disk dynamics and jet generation. We will perform simulations with various incoming flows from an accompanying star.

  8. 3-D General Relativistic MHD Simulations of Generating Jets

    NASA Astrophysics Data System (ADS)

    Nishikawa, K.-I.; Koide, S.; Shibata, K.; Kudoh, T.; Sol, H.; Hughes, J. P.

    2000-12-01

    We have investigated the dynamics of an accretion disk around Schwarzschild black holes initially threaded by a uniform poloidal magnetic field in a non-rotating corona (either in a steady-state infalling state) around a non-rotating black hole using a 3-D GRMHD with the ``axisymmetry'' along the z-direction. Magnetic field is tightly twisted by the rotation of the disk, and plasmas in the shocked region of the disk are accelerated by J x B force to form bipolar relativistic jets. In order to investigate variabilities of generated relativistic jets and magnetic field structure inside jets, we have performed calculations using the 3-D GRMHD code with a full 3-dimensional system. We will investigate how the third dimension affects the global disk dynamics and jet generation.

  9. 3-D General Relativistic MHD Simulations of Generating Jets

    NASA Astrophysics Data System (ADS)

    Nishikawa, Ken-Ichi; Koide, Shinji; Shibata, Kazunari; Kudoh, Takashiro; Sol, Helene; Hughes, John

    2002-04-01

    We have investigated the dynamics of an accretion disk around Schwarzschild black holes initially threaded by a uniform poloidal magnetic field in a non-rotating corona (either in a steady-state infalling state) around a non-rotating black hole using a 3-D GRMHD with the ``axisymmetry'' along the z-direction. Magnetic field is tightly twisted by the rotation of the disk, and plasmas in the shocked region of the disk are accelerated by J × B force to form bipolar relativistic jets. In order to investigate variabilities of generated relativistic jets and magnetic field structure inside jets, we have performed calculations using the 3-D GRMHD code with a full 3-dimensional system without the axisymmetry. We have investigated how the third dimension affects the global disk dynamics and jet generation. We will perform simulations with various incoming flows from an accompanying star.

  10. Geosynchronous Electron Fluxes and Chorus Generation During an MHD Substorm

    NASA Astrophysics Data System (ADS)

    Woodroffe, J. R.; Jordanova, V.; Henderson, M. G.; Welling, D. T.; Vernon, L.

    2015-12-01

    We present results from a numerical study of electron dynamics and whistler generation during an idealized substorm simulated using the Space Weather Modeling Framework. The time-dependent electric and magnetic fields from this simulated substorm are used to drive a new backwards particle tracing model, and the results from this model are used to identify the regions responsible for populating geosynchronous orbit during and after the substorm. Liouville mapping is then used to obtain electron fluxes at geosynchronous orbit as well as to assess the development of anisotropy during the earthward propagation of the electron injection.

  11. 3-D General Relativistic MHD Simulations of Generating Jets

    NASA Astrophysics Data System (ADS)

    Nishikawa, K.-I.; Koide, S.; Shibata, K.; Kudoh, T.; Frank, J.; Sol, H.

    1999-05-01

    Koide et al have investigated the dynamics of an accretion disk initially threaded by a uniform poloidal magnetic field in a non-rotating corona (either in a steady-state infalling state or in hydrostatic equilibrium) around a non-rotating black hole using a 3-D GRMHD with the ``axisymmetry'' along the z-direction. Magnetic field is tightly twisted by the rotation of the disk, and plasmas in the shocked region of the disk are accelerated by J x B force to form bipolar relativistic jets. In order to investigate variabilities of generated relativistic jets and magnetic field structure inside jets, we have performed calculations using the 3-D GRMHD code on a full 3-dimensional system. We will investigate how the third dimension affects the global disk dynamics. 3-D RMHD simulations wil be also performed to investigate the dynamics of a jet with a helical mangetic field in it.

  12. High-enthalpy extraction demonstration with closed-cycle disk MHD generators

    SciTech Connect

    Harada, N.; Suekane, T.; Tsunoda, K.; Yamasaki, H.; Shioda, S.

    1996-01-01

    Recent results of high-enthalpy extraction experiments with closed-cycle MHD disk generators are described. Power generation experiments were carried out with two types of facility: the shock tube facility with the Disk-IV generator and the FUJI-1-blow-down facility. In the shock tube experiments, the effect of channel shape on generator performance was studied using helium seeded with cesium as working fluid. A more divergent channel shape was effective in sustaining a high Hall field throughout the channel and achieving high generator performance even under the strong MHD interaction. High-enthalpy extraction of 27.3% was achieved. Furthermore, these experimental results agree well with the result of one-dimensional calculations. In the FUJI-1 blow-down experiments, the effect of stagnation gas pressure on performance was studied with a working gas of seeded argon. The highest enthalpy extraction ratio of 15.7% was achieved with the lower stagnation pressure of 0.46 MPa, whereas the largest output power of 516.7 kW and power density of 70 MW/m{sup 3} were extracted with the nominal stagnation pressure of 0.6 MPa. This suggested the possibility of a part-load operation without significant degradation of generator performance by reducing stagnation pressure.

  13. High magnetic field MHD generator program. Final report, July 1, 1976-December 31, 1979

    SciTech Connect

    Eustis, R. H.; Kruger, C. H.; Mitchner, M.; Self, S. A.; Koester, J. K.; Nakamura, T.

    1980-04-01

    A theoretical and experimental program was undertaken to investigate MHD channel phenomena which are important at high magnetic fields. The areas studied were inhomogeneity effects, boundary layers, Hall field breakdown and electrode configuration and current concentrations. In addition, a program was undertaken to study steady-state combustion disk and linear channels in an existing 6 Tesla magnet of small dimensions. The structure of the inhomogeneities in the Stanford M-2 was characterized and compared with theoretical results from a linearized perturbation analysis. General agreement was obtained and the analysis was used to compute stability regions for large size generators. The Faraday electrical connection was found to be more stable than the Hall or diagonal wall connections. Boundary layer profile measurements were compared with theoretical calculations with good agreement. Extrapolation of the calculations to pilot scale MHD channels indicates that Hartmann effects are important in the analysis of the sidewall, and Joule heating is important in calculating heat transfer and voltage drops for the electrode wall. Hall field breakdown was shown to occur both in the plasma and through the interelectrode insulator with the insulator breakdown threshold voltage lower than the plasma value. The threshold voltage was shown to depend on the interelectrode gap but was relatively independent of plasma conditions. Experiments were performed at 5.5 Tesla with both disk and linear MHD channels.

  14. Self-consistent stationary MHD shear flows in the solar atmosphere as electric field generators

    NASA Astrophysics Data System (ADS)

    Nickeler, D. H.; Karlický, M.; Wiegelmann, T.; Kraus, M.

    2014-09-01

    Context. Magnetic fields and flows in coronal structures, for example, in gradual phases in flares, can be described by 2D and 3D magnetohydrostatic (MHS) and steady magnetohydrodynamic (MHD) equilibria. Aims: Within a physically simplified, but exact mathematical model, we study the electric currents and corresponding electric fields generated by shear flows. Methods: Starting from exact and analytically calculated magnetic potential fields, we solved the nonlinear MHD equations self-consistently. By applying a magnetic shear flow and assuming a nonideal MHD environment, we calculated an electric field via Faraday's law. The formal solution for the electromagnetic field allowed us to compute an expression of an effective resistivity similar to the collisionless Speiser resistivity. Results: We find that the electric field can be highly spatially structured, or in other words, filamented. The electric field component parallel to the magnetic field is the dominant component and is high where the resistivity has a maximum. The electric field is a potential field, therefore, the highest energy gain of the particles can be directly derived from the corresponding voltage. In our example of a coronal post-flare scenario we obtain electron energies of tens of keV, which are on the same order of magnitude as found observationally. This energy serves as a source for heating and acceleration of particles.

  15. Mark.

    ERIC Educational Resources Information Center

    Lipman, Matthew; Smith, Theresa L., Ed.

    Mark is the central character in this story designed to help adolescents formulate a philosophy of values. The story is well suited for use in high school social studies courses and/or in philosophy or guidance units. Mark's thoughts and actions are reported as he interacts with his family, friends, acquaintances, and individuals of authority…

  16. Operation of a railgun accelerator for solid projectiles powered from an explosive MHD generator

    SciTech Connect

    Shvetsov, G.A.; Bashkatov, Y.L.; Orgov, A.V.; Stadnichenko, I.A.; Titov, V.M.

    1984-11-01

    These authors investigate the possibility of using an explosive MHD generator whose electrodes consist of the rails of a railgun accelerator so that the projectile is anitially accelerated by the action of electromagnetic forces and then, once the gas-cumulative jets reach the body, it can be subjected to additional acceleration by the gas flow moving at a high rate of speed. They conclude that the proposed compounded electrodynamic and gasdynamic acceleration scheme holds promise for achieving velocities in the 5-10 km/sec range.

  17. Key contributions in MHD power generation. Quarterly technical progress report, September 1, 1979-November 30, 1979

    SciTech Connect

    Louis, J F

    1980-03-01

    Separate entries were made in the data base for the four tasks which include: (1) investigation of electrical behavior in the vicinity of electrode and insulating walls; (2) studies of critical performance issues in the development of combustion disk generators; (3) development and testing of electrode modules, including studies of insulator properties; and (4) determination of coal combustion kinetics and ash behavior relevant to two-stage MHD combustors, and investigation of the mixing and flow aerodynamics of a high swirl geometry second stage. (WHK)

  18. Fault analysis of mid-channel power takeoff in DCW MHD generators

    NASA Astrophysics Data System (ADS)

    Ishikawa, M.; Wu, Y. C. L.; Scott, M. H.

    1982-06-01

    Analysis is presented of the effect of loading faults on the mid-channel power takeoff of a diagonal-conducting-wall MHD generator in special loading schemes. Two-dimensional calculations indicate that an open-circuit condition in the upstream load circuit results in a large current density at the power takeoff anode and drives a shorting current over the interframe insulators at the cathode side. A short-circuit condition in the upstream load circuit results in a large current density at the power takeoff cathode and a shorting current over the interframe insulators at the anode side.

  19. ENDF/B-VII.0: Next Generation Evaluated Nuclear Data Library for Nuclear Science and Technology

    SciTech Connect

    Chadwick, M B; Oblozinsky, P; Herman, M; Greene, N M; McKnight, R D; Smith, D L; Young, P G; MacFarlane, R E; Hale, G M; Haight, R C; Frankle, S; Kahler, A C; Kawano, T; Little, R C; Madland, D G; Moller, P; Mosteller, R; Page, P; Talou, P; Trellue, H; White, M; Wilson, W B; Arcilla, R; Dunford, C L; Mughabghab, S F; Pritychenko, B; Rochman, D; Sonzogni, A A; Lubitz, C; Trumbull, T H; Weinman, J; Brown, D; Cullen, D E; Heinrichs, D; McNabb, D; Derrien, H; Dunn, M; Larson, N M; Leal, L C; Carlson, A D; Block, R C; Briggs, B; Cheng, E; Huria, H; Kozier, K; Courcelle, A; Pronyaev, V; der Marck, S

    2006-10-02

    We describe the next generation general purpose Evaluated Nuclear Data File, ENDF/B-VII.0, of recommended nuclear data for advanced nuclear science and technology applications. The library, released by the U.S. Cross Section Evaluation Working Group (CSEWG) in December 2006, contains data primarily for reactions with incident neutrons, protons, and photons on almost 400 isotopes. The new evaluations are based on both experimental data and nuclear reaction theory predictions. The principal advances over the previous ENDF/B-VI library are the following: (1) New cross sections for U, Pu, Th, Np and Am actinide isotopes, with improved performance in integral validation criticality and neutron transmission benchmark tests; (2) More precise standard cross sections for neutron reactions on H, {sup 6}Li, {sup 10}B, Au and for {sup 235,238}U fission, developed by a collaboration with the IAEA and the OECD/NEA Working Party on Evaluation Cooperation (WPEC); (3) Improved thermal neutron scattering; (4) An extensive set of neutron cross sections on fission products developed through a WPEC collaboration; (5) A large suite of photonuclear reactions; (6) Extension of many neutron- and proton-induced reactions up to an energy of 150 MeV; (7) Many new light nucleus neutron and proton reactions; (8) Post-fission beta-delayed photon decay spectra; (9) New radioactive decay data; and (10) New methods developed to provide uncertainties and covariances, together with covariance evaluations for some sample cases. The paper provides an overview of this library, consisting of 14 sublibraries in the same, ENDF-6 format, as the earlier ENDF/B-VI library. We describe each of the 14 sublibraries, focusing on neutron reactions. Extensive validation, using radiation transport codes to simulate measured critical assemblies, show major improvements: (a) The long-standing underprediction of low enriched U thermal assemblies is removed; (b) The {sup 238}U, {sup 208}Pb, and {sup 9}Be reflector

  20. ENDF/B-VII.0: Next Generation Evaluated Nuclear Data Library for Nuclear Science and Technology

    NASA Astrophysics Data System (ADS)

    Chadwick, M. B.; Obložinský, P.; Herman, M.; Greene, N. M.; McKnight, R. D.; Smith, D. L.; Young, P. G.; MacFarlane, R. E.; Hale, G. M.; Frankle, S. C.; Kahler, A. C.; Kawano, T.; Little, R. C.; Madland, D. G.; Moller, P.; Mosteller, R. D.; Page, P. R.; Talou, P.; Trellue, H.; White, M. C.; Wilson, W. B.; Arcilla, R.; Dunford, C. L.; Mughabghab, S. F.; Pritychenko, B.; Rochman, D.; Sonzogni, A. A.; Lubitz, C. R.; Trumbull, T. H.; Weinman, J. P.; Brown, D. A.; Cullen, D. E.; Heinrichs, D. P.; McNabb, D. P.; Derrien, H.; Dunn, M. E.; Larson, N. M.; Leal, L. C.; Carlson, A. D.; Block, R. C.; Briggs, J. B.; Cheng, E. T.; Huria, H. C.; Zerkle, M. L.; Kozier, K. S.; Courcelle, A.; Pronyaev, V.; van der Marck, S. C.

    2006-12-01

    We describe the next generation general purpose Evaluated Nuclear Data File, ENDF/B-VII.0, of recommended nuclear data for advanced nuclear science and technology applications. The library, released by the U.S. Cross Section Evaluation Working Group (CSEWG) in December 2006, contains data primarily for reactions with incident neutrons, protons, and photons on almost 400 isotopes, based on experimental data and theory predictions. The principal advances over the previous ENDF/B-VI library are the following: (1) New cross sections for U, Pu, Th, Np and Am actinide isotopes, with improved performance in integral validation criticality and neutron transmission benchmark tests; (2) More precise standard cross sections for neutron reactions on H, 6Li, 10B, Au and for 235,238U fission, developed by a collaboration with the IAEA and the OECD/NEA Working Party on Evaluation Cooperation (WPEC); (3) Improved thermal neutron scattering; (4) An extensive set of neutron cross sections on fission products developed through a WPEC collaboration; (5) A large suite of photonuclear reactions; (6) Extension of many neutron- and proton-induced evaluations up to 150 MeV; (7) Many new light nucleus neutron and proton reactions; (8) Post-fission beta-delayed photon decay spectra; (9) New radioactive decay data; (10) New methods for uncertainties and covariances, together with covariance evaluations for some sample cases; and (11) New actinide fission energy deposition. The paper provides an overview of this library, consisting of 14 sublibraries in the same ENDF-6 format as the earlier ENDF/B-VI library. We describe each of the 14 sublibraries, focusing on neutron reactions. Extensive validation, using radiation transport codes to simulate measured critical assemblies, show major improvements: (a) The long-standing underprediction of low enriched uranium thermal assemblies is removed; (b) The 238U and 208Pb reflector biases in fast systems are largely removed; (c) ENDF/B-VI.8 good

  1. Analysis of Fluctuations in a Combustion-Driven Open-Cycle MHD Generator.

    NASA Astrophysics Data System (ADS)

    Skorska, Malgorzata Bozena

    Fluctuations present in MHD generators may cause significant degradation in the generated power. The fluctuations may result from three sources. First, the mass flow rates of the components' input to the combustor vary. Second, the combustor initiates its own variations which are functions of the combustor geometry and injection techniques. Third, the generator action, i.e., flow of plasma in a magnetic field, introduces variations in the plasma variables. The purpose of the study is to investigate the fluctuations of MHD output signals, which may either arise from the combustor fluctuations propagating into a conducting channel, or are inherent in the generator dynamics. The analysis of fluctuations is based on the analytical and empirical models. Both models assume that stochastic processes take place within the MHD plasma, and both models yield results in the form of autocorrelation, crosscorrelation, and power spectral density functions of the system variables. The study showed that fluctuations, whose frequencies exceed 200 Hz, in the plasma density, velocity, pressure, current and voltage variables are acoustic in nature, and are caused by longitudinal standing waves present in the generator. The analysis proved that Hall generators develop fluctuations mainly in the range 700 Hz to 2000 Hz, whereas Faraday and DCW generators are favorable for the low frequency fluctuations. Parametric study of the plasma disclosed that stronger magnetic fields and larger Hall parameters increase the frequency range of fluctuations. Changes in plasma specific heat ratio or in inlet steady-state parameters may increase or decrease the intensities of some odd harmonics of the standing waves. The fluctuations that originate in the combustion chamber also affect the plasma variables. A white noise character of these fluctuations guarantees a fairly uniform distribution of energy in the fluctuations of the plasma variables in the frequency range up to 200 Hz. Future research in

  2. FLASH MHD simulations of experiments that study shock-generated magnetic fields

    NASA Astrophysics Data System (ADS)

    Tzeferacos, P.; Fatenejad, M.; Flocke, N.; Graziani, C.; Gregori, G.; Lamb, D. Q.; Lee, D.; Meinecke, J.; Scopatz, A.; Weide, K.

    2015-12-01

    We summarize recent additions and improvements to the high energy density physics capabilities in FLASH, highlighting new non-ideal magneto-hydrodynamic (MHD) capabilities. We then describe 3D Cartesian and 2D cylindrical FLASH MHD simulations that have helped to design and analyze experiments conducted at the Vulcan laser facility. In these experiments, a laser illuminates a carbon rod target placed in a gas-filled chamber. A magnetic field diagnostic (called a Bdot) employing three very small induction coils is used to measure all three components of the magnetic field at a chosen point in space. The simulations have revealed that many fascinating physical processes occur in the experiments. These include megagauss magnetic fields generated by the interaction of the laser with the target via the Biermann battery mechanism, which are advected outward by the vaporized target material but decrease in strength due to expansion and resistivity; magnetic fields generated by an outward expanding shock via the Biermann battery mechanism; and a breakout shock that overtakes the first wave, the contact discontinuity between the target material and the gas, and then the initial expanding shock. Finally, we discuss the validation and predictive science we have done for this experiment with FLASH.

  3. Transient Phenomena of Disk MHD Generator due to Change of Load Resistance

    NASA Astrophysics Data System (ADS)

    Koka, Hidetoshi; Okuno, Yoshihiro; Yamasaki, Hiroyuki

    Results of experimental study on transient phenomena of the closed cycle disk MHD generator are described in this paper. The transient phenomena were caused by a step-like change of load resistance during a test time of the shock-tube driven disk MHD generator. The load resistance was changed by using an IGBT (Insulated Gate Bipolar Transistor) installed in a load circuit. When the load resistance was changed from 0.096Ω to 2.5Ω, an overshoot of the Hall output voltage and of the Hall electric field was observed, and a large fluctuation of static pressure was also observed. At the same time, a spike-like increase of cesium recombination continuum and line spectrum appeared just after the load change. Results of the quasi-one dimensional numerical simulation have indicated that the observed overshoot was caused by the following phenomena: 1) a steep reduction of the Hall current and a steep increase in both the Faraday current and the electrical conductivity, and 2) a slow reduction of gas velocity due to the enhanced retarding force. Furthermore, the measured spike-like increase of radiation intensity was ascribed to an increase of electron temperature and electron number density by a steep increase of Joule heating.

  4. Four-piston double-duct liquid metal MHD engine and AC generator

    SciTech Connect

    Haaland, C.M.

    1995-12-31

    Operating principles, features and applications of the Liquid Metal (LM) engine are presented. This engine combines a free-piston internal combustion engine with an MHD AC power generator. Liquid metal (LM) oscillates back-and-forth in two separate channels, driven by free pistons coupled magnetically to pistons driven by internal combustion. One of the principal breakthroughs is the concept of using double ducts in a Hartmann configuration for MHD production of alternating current. The LM flows in opposing directions in the two adjacent Hartmann ducts, thus eliminating magnetic-induced instabilities, eliminating vibration, and providing an ideal setup for attaching an output transformer on one side provide to provide useful ranges of current and voltage. Because LM is used, the length of the piston stroke can be easily varied over a large range, thus making possible an engine that, changes size, according to variation in output load requirements. Increasing the stroke length results in increased compression ratio, which requires computer controlled modification of the fuel injection mixture. Higher fuel efficiencies will result, whether the engine is idling or operating at maximum power. Because of viscous dissipation losses in the LM, this engine will be more efficient for larger engines. Applications include any power generation where variable load is required, such as stationary electric generators for remote towns and cities, temporary military encampments, and mobile primary power generators for off-road and on-road automotive equipment, including caterpillars, cars, military vehicles, trucks, and trains. The advantages for automotive propulsion will be described in comparisons with current and developmental vehicles using internal combustion engines. Because the LM-engine generates electricity, an LM-engine vehicle is readily adaptable to hybrid concepts. An R&D program will be outlined for bringing the concept of the LM engine to commercial application.

  5. Integration of MHD load models with circuit representations the Z generator.

    SciTech Connect

    Jennings, Christopher A.; Ampleford, David J.; Jones, Brent Manley; McBride, Ryan D.; Bailey, James E.; Jones, Michael C.; Gomez, Matthew Robert.; Cuneo, Michael Edward; Nakhleh, Charles; Stygar, William A.; Savage, Mark Edward; Wagoner, Timothy C.; Moore, James K.

    2013-03-01

    MHD models of imploding loads fielded on the Z accelerator are typically driven by reduced or simplified circuit representations of the generator. The performance of many of the imploding loads is critically dependent on the current and power delivered to them, so may be strongly influenced by the generators response to their implosion. Current losses diagnosed in the transmission lines approaching the load are further known to limit the energy delivery, while exhibiting some load dependence. Through comparing the convolute performance of a wide variety of short pulse Z loads we parameterize a convolute loss resistance applicable between different experiments. We incorporate this, and other current loss terms into a transmission line representation of the Z vacuum section. We then apply this model to study the current delivery to a wide variety of wire array and MagLif style liner loads.

  6. The generation and damping of propagating MHD kink waves in the solar atmosphere

    SciTech Connect

    Morton, R. J.; Verth, G.; Erdélyi, R.; Hillier, A. E-mail: g.verth@sheffield.ac.uk

    2014-03-20

    The source of the non-thermal energy required for the heating of the upper solar atmosphere to temperatures in excess of a million degrees and the acceleration of the solar wind to hundreds of kilometers per second is still unclear. One such mechanism for providing the required energy flux is incompressible torsional Alfvén and kink magnetohydrodynamic (MHD) waves, which are magnetically dominated waves supported by the Sun's pervasive and complex magnetic field. In particular, propagating MHD kink waves have recently been observed to be ubiquitous throughout the solar atmosphere, but, until now, critical details of the transport of the kink wave energy throughout the Sun's atmosphere were lacking. Here, the ubiquity of the waves is exploited for statistical studies in the highly dynamic solar chromosphere. This large-scale investigation allows for the determination of the chromospheric kink wave velocity power spectra, a missing link necessary for determining the energy transport between the photosphere and corona. Crucially, the power spectra contain evidence for horizontal photospheric motions being an important mechanism for kink wave generation in the quiescent Sun. In addition, a comparison with measured coronal power spectra is provided for the first time, revealing frequency-dependent transmission profiles, suggesting that there is enhanced damping of kink waves in the lower corona.

  7. An innovative demonstration of high power density in a compact MHD (magnetohydrodynamic) generator

    SciTech Connect

    Schmidt, H.J.; Lineberry, J.T.; Chapman, J.N.

    1990-06-01

    The present program was conducted by the University of Tennessee Space Institute (UTSI). It was by its nature a high risk experimental program to demonstrate the feasibility of high power density operation in a laboratory scale combustion driven MHD generator. Maximization of specific energy was not a consideration for the present program, but the results have implications in this regard by virtue of high energy fuel used. The power density is the ratio of the electrical energy output to the internal volume of the generator channel. The MHD process is a volumetric process and the power density is therefore a direct measure of the compactness of the system. Specific energy, is the ratio of the electrical energy output to consumable energy used for its production. The two parameters are conceptually interrelated. To achieve high power density and implied commensurate low system volume and weight, it was necessary to use an energetic fuel. The high energy fuel of choice was a mixture of powdered aluminum and carbon seeded with potassium carbonate and burned with gaseous oxygen. The solid fuel was burned in a hybrid combustion scheme wherein the fuel was cast within a cylindrical combustor in analogy with a solid propellant rocket motor. Experimental data is limited to gross channel output current and voltage, magnetic field strength, fuel and oxidizer flow rates, flow train external temperatures and combustor pressure. Similarly, while instantaneous oxidizer flow rates were measured, only average fuel consumption based on pre and post test component weights and dimensions was possible. 4 refs., 60 figs., 9 tabs.

  8. Design and calculated performance and cost of the ECAS Phase II open cycle MHD power generation system

    NASA Technical Reports Server (NTRS)

    Harris, L. P.

    1977-01-01

    A 2000 MWe MHD/steam plant for central station applications has been designed and costed as part of the Energy Conversion Alternatives Study (ECAS). This plant is fueled by Illinois No. 6 coal, rejects heat through mechanical draft wet cooling towers, and includes coal processing equipment, seed reprocessing, electrical inversion of the MHD generator output and emission controls to current EPA standards. It yields an estimated overall efficiency of 0.483 (7066 Btu/kWe-hr), a capital cost of $718 per kWe (1975 dollars), and a cost of electricity at 65% capacity factor of 32 mills per kWe-hr. If the assumed life and reliability could be achieved with these performance parameters, the MHD system should prove attractive.

  9. Virtual Tool Mark Generation for Efficient Striation Analysis

    SciTech Connect

    Ekstrand, Laura; Zhang, Song; Grieve, Taylor; Chumbley, L Scott; Kreiser, M James

    2014-02-16

    This study introduces a tool mark analysis approach based upon 3D scans of screwdriver tip and marked plate surfaces at the micrometer scale from an optical microscope. An open-source 3D graphics software package is utilized to simulate the marking process as the projection of the tip's geometry in the direction of tool travel. The edge of this projection becomes a virtual tool mark that is compared to cross-sections of the marked plate geometry using the statistical likelihood algorithm introduced by Chumbley et al. In a study with both sides of six screwdriver tips and 34 corresponding marks, the method distinguished known matches from known nonmatches with zero false-positive matches and two false-negative matches. For matches, it could predict the correct marking angle within ±5–10°. Individual comparisons could be made in seconds on a desktop computer, suggesting that the method could save time for examiners.

  10. Virtual tool mark generation for efficient striation analysis.

    PubMed

    Ekstrand, Laura; Zhang, Song; Grieve, Taylor; Chumbley, L Scott; Kreiser, M James

    2014-07-01

    This study introduces a tool mark analysis approach based upon 3D scans of screwdriver tip and marked plate surfaces at the micrometer scale from an optical microscope. An open-source 3D graphics software package is utilized to simulate the marking process as the projection of the tip's geometry in the direction of tool travel. The edge of this projection becomes a virtual tool mark that is compared to cross-sections of the marked plate geometry using the statistical likelihood algorithm introduced by Chumbley et al. In a study with both sides of six screwdriver tips and 34 corresponding marks, the method distinguished known matches from known nonmatches with zero false-positive matches and two false-negative matches. For matches, it could predict the correct marking angle within ±5-10°. Individual comparisons could be made in seconds on a desktop computer, suggesting that the method could save time for examiners.

  11. Results of closed cycle MHD power generation test with a helium-cesium working fluid

    NASA Technical Reports Server (NTRS)

    Sovie, R. J.

    1977-01-01

    The cross sectional dimensions of the MHD channel in the NASA Lewis closed loop facility were reduced to 3.8 x 11.4 cm. Tests were run in this channel using a helium-cesium working fluid at stagnation pressures of 160,000 n/M2, stagnation temperatures of 2000-2060 K and an entrance Mach number of 0.36. In these tests Faraday open circuit voltages of 200 V were measured which correspond to a Faraday field of 1750 V/M. Power generation tests were run for different groups of electrode configurations and channel lengths. Hall fields up to 1450 V/M were generated. Power extraction per electrode of 183 W and power densities of 1.7 MW/M3 were obtained. A total power output of 2 kW was generated for tests with 14 electrodes. The power densities obtained in this channel represent a factor of 3 improvement over those previously reported for the M = 0.2 channel.

  12. Results of closed cycle MHD power generation tests with a helium-cesium working fluid

    NASA Technical Reports Server (NTRS)

    Sovie, R. J.

    1977-01-01

    The cross-sectional dimensions of the MHD channel in the NASA Lewis closed loop facility have been reduced to 3.8 x 11.4 cm. Tests were run in this channel using a helium-cesium working fluid at stagnation pressures of 1.6 x 10 to the 5th N/sq m, stagnation temperatures of 2000-2060 K and an entrance Mach number of 0.36. In these tests Faraday open circuit voltages of 200 V were measured which correspond to a Faraday field of 1750 V/m. Power generation tests were run for different groups of electrode configurations and channel lengths. Hall fields up to 1450 V/m were generated. Power extraction per electrode of 183 W and power densities of 1.7 MW/cu m have been obtained. A total power output of 2 kW was generated for tests with 14 electrodes. The power densities obtained in this channel represent a factor of 3 improvement over those reported for the m = 0.2 channel at the last EAM Symposium.

  13. Comparison of Performances of Scramjet-Driven Experimental DCW-MHD Generators with Different Cross-Section

    NASA Astrophysics Data System (ADS)

    Niwa, Naoyuki; Takahashi, Toru; Fujino, Takayasu; Ishikawa, Motoo

    The purpose of this study is to examine the influence of shape of cross-section of scramjet engine driven experimental DCW-MHD generator on generator performance by three-dimensional numerical analyses. We have designed the MHD generators with symmetric square and circular cross-section, based on the experimental MHD generator with asymmetric square cross-section. Under the optimum load condition, the electric power output becomes 26.6kW for the asymmetric square cross-section, 24.6kW for the symmetric square cross-section, and 22.4kW for the circular cross-section. The highest output is obtained for the experimental generator with asymmetric square cross-section. The difference of electric power output is induced by the difference of flow velocity and boundary layer thickness. For the generator with asymmetric square cross-section, the average flow velocity becomes the highest and the boundary layer becomes the thinnest. The compression wave is generated depending on the channel shape. The difference of flow velocity and boundary layer thickness is induced by the superposition of compression wave.

  14. Experimental results of the UTSI coal-fired MHD generator and investigations of various power take-off schemes

    NASA Astrophysics Data System (ADS)

    Galanga, F. L.; Lineberry, J. T.; Wu, Y. C. L.; Scott, M. H.; Baucum, W. E.; Clemons, R. W.

    1981-01-01

    Tests were conducted at the University of Tennessee Space Institute, Energy Conversion Division, in support of technology development of coal-fired MHD generator systems. The primary objectives of the test series were to evaluate the overall electrical performance of the 60 deg DCW generator with vitiation heated oxidizer, to study the thermal behavior of capped versus solid frame electrodes, and to investigate various power take-off schemes. Results from the above-mentioned areas of investigation are presented and discussed.

  15. US/USSR cooperative program in open-cycle MHD electrical power generation: joint test report No. 3. Tests in the U-25B facility: MHD generator tests No. 4 and 5

    SciTech Connect

    Picologlou, B F; Batenin, V M

    1980-07-01

    A description of the modifications made to improve the plasma parameters of the U-25B Facility is presented. The oxygen enrichment system was modified to allow oxygen enrichment of up to 50% (by volume) ahead of the preheaters. Optimum design and operating conditions of the seed injection system were defined as a result of experimental investigations. An account of the extensive diagnostic studies performed and a description of the measurement techniques and of the new submillimeter laser interferometer are given. The performance of the MHD generator is analyzed for different operating modes. Studies of fluctuations and nonuniformities, current take-off distributions, local electrical analysis, overall heat transfer history of the MHD channel, and an extensive parametric study of the generator are presented. A detailed account of the complete disassembly and inspection of channel No. 1 after more than 100 hours of operation with the combustor, and of the condition of its various elements is also given.

  16. US/USSR cooperative program in open-cycle MHD electrical power generation: joint test report No. 4. Tests in the U-25B facility: MHD generator tests No. 6 and 7

    SciTech Connect

    Picologlou, B F; Batenin, V M

    1981-01-01

    A description of the main results obtained during Tests No. 6 and 7 at the U-25B Facility using the new channel No. 2 is presented. The purpose of these tests was to operate the MHD generator at its design parameters. Described here are new plasma diagnostic devices: a traversing dual electrical probe for determining distribution of electron concentrations, and a traversing probe that includes a pitot tube for measuring total and static pressure, and a light detector for measuring plasma luminescence. Data are presented on heat flux distribution along the channel, the first data of this type obtained for an MHD facility of such size. Results are given of experimental studies of plasma characteristics, gasdynamic, thermal, and electrical MHD channel performance, and temporal and spatial nonuniformities. Typical modes of operation are analyzed by means of local electrical analyses. Computer models are used to obtain predictions for both localized and overall generator characteristics. These theoretical predictions agree closely with the results of the local analyses, as well as with measurements of the overall gasdynamic and electrical characteristics of the generator.

  17. Design study of superconducting magnets for a combustion magnetohydrodynamic /MHD/ generator

    NASA Technical Reports Server (NTRS)

    Thome, R. J.; Ayers, J. W.; Hrycaj, T. M.; Burkhart, J. A.

    1978-01-01

    Results are presented for a trade-off and preliminary design study on concepts of a superconducting magnet system for a combustion MHD generator test facility. The main objective is to gain insight into the magnitude of the project in terms of physical characteristics and cost. The net result of a first-phase evaluation of attractive design alternatives is to concentrate subsequent efforts on (1) a racetrack coil geometry with an operating temperature of 4.2 K, (2) a racetrack coil geometry with an operating temperature of 2.0 K, and (3) a rectangular saddle coil geometry with an operating temperature of 4.2 K. All three systems are to produce 8 T, and use NbTi superconductor and iron for field enhancement. Design characteristics of the three systems are described. It is shown that the racetrack and rectangular saddle coil geometries seem most suitable for this application, the former because of its simplicity and the latter because of its efficient use of material. Advantages of the rectangular saddle over the two other systems are stressed.

  18. Evaluation of technical feasibility of closed-cycle non-equilibrium MHD power generation with direct coal firing. Final report, Task I

    SciTech Connect

    Not Available

    1981-11-01

    Program accomplishments in a continuing effort to demonstrate the feasibility of direct coal-fired, closed-cycle MHD power generation are reported. This volume contains the following appendices: (A) user's manual for 2-dimensional MHD generator code (2DEM); (B) performance estimates for a nominal 30 MW argon segmented heater; (C) the feedwater cooled Brayton cycle; (D) application of CCMHD in an industrial cogeneration environment; (E) preliminary design for shell and tube primary heat exchanger; and (F) plant efficiency as a function of output power for open and closed cycle MHD power plants. (WHK)

  19. COMBINE7.1 - A Portable ENDF/B-VII.0 Based Neutron Spectrum and Cross-Section Generation Program

    SciTech Connect

    Woo Y. Yoon; David W. Nigg

    2009-08-01

    COMBINE7.1 is a FORTRAN 90 computer code that generates multigroup neutron constants for use in the deterministic diffusion and transport theory neutronics analysis. The cross-section database used by COMBINE7.1 is derived from the Evaluated Nuclear Data Files (ENDF/B-VII.0). The neutron energy range covered is from 20 MeV to 1.0E-5 eV. The Los Alamos National Laboratory NJOY code is used as the processing code to generate a 167 fine-group cross-section library in MATXS format for Bondarenko self-shielding treatment. Resolved resonance parameters are extracted from ENDF/B-VII.0 File 2 for a separate library to be used in an alternate Nordheim self-shielding treatment in the resolved resonance energy range. The equations solved for energy dependent neutron spectrum in the 167 fine-group structure are the B-3 or B-1 approximations to the transport equation. The fine group cross sections needed for the spectrum calculation are first prepared by Bondarenko self-shielding interpolation in terms of background cross section and temperature. The geometric lump effect, when present, is accounted for by augmenting the background cross section. Nordheim self-shielded fine group cross sections for a material having resolved resonance parameters overwrite correspondingly the existing self-shielded fine group cross sections when this option is used. The fine group cross sections in the thermal energy range are replaced by those self-shielded with the Amouyal/Benoist/Horowitz method in the three region geometry when this option is requested. COMBINE7.1 coalesces fine group cross sections into broad group macroscopic and microscopic constants. The coalescing is performed by utilizing fine-group fluxes and/or currents obtained by spectrum calculation as the weighting functions. The multigroup constant may be output in any of several standard formats including ANISN 14** free format, CCCC ISOTXS format, and AMPX working library format. ANISN-PC, a one-dimensional, discrete

  20. COMBINE7.0 - A Portable ENDF/B-VII.0 Based Neutron Spectrum and Cross-Section Generation Program

    SciTech Connect

    Woo Y. Yoon; David W. Nigg

    2008-09-01

    COMBINE7.0 is a FORTRAN 90 computer code that generates multigroup neutron constants for use in the deterministic diffusion and transport theory neutronics analysis. The cross-section database used by COMBINE7.0 is derived from the Evaluated Nuclear Data Files (ENDF/B-VII.0). The neutron energy range covered is from 20 MeV to 1.0E-5 eV. The Los Alamos National Laboratory NJOY code is used as the processing code to generate a 167 finegroup cross-section library in MATXS format for Bondarenko self-shielding treatment. Resolved resonance parameters are extracted from ENDF/B-VII.0 File 2 for a separate library to be used in an alternate Nordheim self-shielding treatment in the resolved resonance energy range. The equations solved for energy dependent neutron spectrum in the 167 fine-group structure are the B-3 or B-1 approximations to the transport equation. The fine group cross sections needed for the spectrum calculation are first prepared by Bondarenko selfshielding interpolation in terms of background cross section and temperature. The geometric lump effect, when present, is accounted for by augmenting the background cross section. Nordheim self-shielded fine group cross sections for a material having resolved resonance parameters overwrite correspondingly the existing self-shielded fine group cross sections when this option is used. The fine group cross sections in the thermal energy range are replaced by those selfshielded with the Amouyal/Benoist/Horowitz method in the three region geometry when this option is requested. COMBINE7.0 coalesces fine group cross sections into broad group macroscopic and microscopic constants. The coalescing is performed by utilizing fine-group fluxes and/or currents obtained by spectrum calculation as the weighting functions. The multigroup constant may be output in any of several standard formats including ANISN 14** free format, CCCC ISOTXS format, and AMPX working library format. ANISN-PC, a onedimensional, discrete

  1. The energy associated with MHD waves generation in the solar wind plasma

    NASA Technical Reports Server (NTRS)

    delaTorre, A.

    1995-01-01

    Gyrotropic symmetry is usually assumed in measurements of electron distribution functions in the heliosphere. This prevents the calculation of a net current perpendicular to the magnetic field lines. Previous theoretical results derived by one of the authors for a collisionless plasma with isotropic electrons in a strong magnetic field have shown that the excitation of MHD modes becomes possible when the external perpendicular current is non-zero. We consider then that any anisotropic electron population can be thought of as 'external', interacting with the remaining plasma through the self-consistent electromagnetic field. From this point of view any perpendicular current may be due to the anisotropic electrons, or to an external source like a stream, or to both. As perpendicular currents cannot be derived from the measured distribution functions, we resort to Ampere's law and experimental data of magnetic field fluctuations. The transfer of energy between MHD modes and external currents is then discussed.

  2. Generator coordinate method and nuclear collective motions (VII): the preservation of symmetry properties

    SciTech Connect

    XU Gong-ou

    1985-01-01

    In order to preserve all the symmetry properties for the effective collective Hamiltonian obtained with the generator coordinate method, it is necessary for the trial wave function to have proper transformation properties. The generator coordinates should then transform in the same way as the represented collective operators. Also, the center-of-mass motion should be independent of the internal motion in conformity with the invariance of the nuclear Hamiltonian with respect to space rotation and Galilean transformation.

  3. COMBINE7.1 - A Portable ENDF/B-VII.0 Based Neutron Spectrum and Cross-Section Generation Program

    SciTech Connect

    Woo Y. Yoon; David W. Nigg

    2011-09-01

    COMBINE7.1 is a FORTRAN 90 computer code that generates multigroup neutron constants for use in the deterministic diffusion and transport theory neutronics analysis. The cross-section database used by COMBINE7.1 is derived from the Evaluated Nuclear Data Files (ENDF/B-VII.0). The neutron energy range covered is from 20 MeV to 1.0E-5 eV. The Los Alamos National Laboratory NJOY code is used as the processing code to generate a 167 fine-group cross-section library in MATXS format for Bondarenko self-shielding treatment. Resolved resonance parameters are extracted from ENDF/B-VII.0 File 2 for a separate library to be used in an alternate Nordheim self-shielding treatment in the resolved resonance energy range. The equations solved for energy dependent neutron spectrum in the 167 fine-group structure are the B3 or B1 zero-dimensional approximations to the transport equation. The fine group cross sections needed for the spectrum calculation are first prepared by Bondarenko self-shielding interpolation in terms of background cross section and temperature. The geometric lump effect, when present, is accounted for by augmenting the background cross section. Nordheim self-shielded fine group cross sections for a material having resolved resonance parameters overwrite correspondingly the existing self-shielded fine group cross sections when this option is used. COMBINE7.1 coalesces fine group cross sections into broad group macroscopic and microscopic constants. The coalescing is performed by utilizing fine-group fluxes and/or currents obtained by spectrum calculation as the weighting functions. The multigroup constants may be output in any of several standard formats including INL format, ANISN 14** free format, CCCC ISOTXS format, and AMPX working library format. ANISN-PC, a one-dimensional (1-D) discrete-ordinate transport code, is incorporated into COMBINE7.1. As an option, the 167 fine-group constants generated by zero-dimensional COMBINE portion in the program can be

  4. Analysis of entropy generation for double diffusive MHD convection in a square cavity with isothermal hollow cylinder

    NASA Astrophysics Data System (ADS)

    Mojumder, Satyajit; Saha, Sourav; Saha, Sumon

    2016-07-01

    Entropy optimization is a major concern for designing modern thermal management system. In the present work, entropy analysis in a square cavity with an isothermal hollow cylinder at the center is carried out for magneto-hydrodynamic (MHD) double diffusive convection. Galerkin weighted residuals method of finite element formulation is adopted for the numerical solution. Entropies due to fluid flow, heat, and mass transfer are computed for wide range of Hartmann (0 ≤ Ha ≤ 50) and Lewis numbers (1 ≤ Le ≤ 15), and buoyancy ratios (-5 ≤ N ≤ 5) at constant Rayleigh and Prandtl numbers. It is found that the influence of buoyancy ratio is prominent on entropy generation, which also depends on both Lewis and Hartmann numbers. The ratio N = -1 shows minimum entropy generation for any combination of Lewis and Hartman numbers. Visualization of isentropic contours and the variation of total entropy with the governing parameters provide remarkable evidences of entropy optimization.

  5. Thrombin generation by activated factor VII on platelet activated by different agonists. Extending the cell-based model of hemostasis

    PubMed Central

    Altman, Raul; Scazziota, Alejandra Silvia; Herrera, Maria de Lourdes; Gonzalez, Claudio

    2006-01-01

    Background Platelet activation is crucial in normal hemostasis. Using a clotting system free of external tissue factor, we investigated whether activated Factor VII in combination with platelet agonists increased thrombin generation (TG) in vitro. Methods and results TG was quantified by time parameters: lag time (LT) and time to peak (TTP), and by amount of TG: peak of TG (PTG) and area under thrombin formation curve after 35 minutes (AUC→35min) in plasma from 29 healthy volunteers using the calibrated automated thrombography (CAT) technique. TG parameters were measured at basal conditions and after platelet stimulation by sodium arachidonate (AA), ADP, and collagen (Col). In addition, the effects of recombinant activated FVII (rFVIIa) alone or combined with the other platelet agonists on TG parameters were investigated. We found that LT and TTP were significantly decreased (p < 0.05) and PTG and AUC→35min were significantly increased (p < 0.05) in platelet rich plasma activated with AA, ADP, Col, and rFVIIa compared to non-activated platelet rich plasma from normal subjects (p = 0.01). Furthermore platelet rich plasma activated by the combined effects of rFVIIa plus AA, ADP or Col had significantly reduced LT and TTP and increased AUC→35min (but not PTG) when compared to platelet rich plasma activated with agonists in the absence of rFVIIa. Conclusion Platelets activated by AA, ADP, Col or rFVIIa triggered TG. This effect was increased by combining rFVIIa with other agonists. Our intrinsic coagulation system produced a burst in TG independent of external tissue factor activity an apparent hemostatic effect with little thrombotic capacity. Thus we suggest a modification in the cell-based model of hemostasis. PMID:16630353

  6. Closed cycle MHD generator with nonuniform gas-plasma flow driving recombinated plasma clots formed by high-energy electron beams

    SciTech Connect

    Danilov, V.V.; Laptev, S.S.; Slavin, V.S.

    1996-12-31

    A new concept of a closed cycle MHD generator without alkali seed has been suggested. The essence of it is the use of the high-energy electron beams technology for a nonuniform gas-plasma flow in MHD channel creation. At the inlet of MHD channel in supersonic flow of noble gas (He) the plasma clots with a density about 10{sup 15} cm{sup {minus}3} are formed by pulsed intense electron beams with energy about 100 keV. Gas flow drives these clots in a cross magnetic field along the MHD channel which has electrodes connected with a load by Faraday`s scheme. Because the nonuniform gas-plasma flow has not the conductivity in the Hall`s EMF direction a Faraday`s current can flow only through the narrow plasma layers. The energy dissipation and Joule`s heating in MHD channel support the nonequilibrium conductivity in these plasma layers. a gas flow pushes current layers and produces electric power at the expense of enthalpy extraction. The key element is a question of plasma layers stability in MHD channel. The most dangerous instability is the overheating instability. it is shown that taking into account the phenomenon of frozen conductivity for recombinated plasma which appears for noble gas at T{sub e} > 4,000 K the regime with {partial_derivative}{sigma}/{partial_derivative}T{sub e} < 0 can be realized. Due to the fulfillment of this condition the overheating instability is effectively suppressed. The numerical simulation has shown that a supersonic gas flow, containing about 4 current layers in MHD channel simultaneously, is braked without shock waves creation. Current layers provide no less than 30% enthalpy extraction and about 80% isentropic efficiency.

  7. Periodic Wnt1 expression in response to ecdysteroid generates twin-spot markings on caterpillars.

    PubMed

    Yamaguchi, Junichi; Banno, Yutaka; Mita, Kazuei; Yamamoto, Kimiko; Ando, Toshiya; Fujiwara, Haruhiko

    2013-01-01

    Among various pigmentation patterns on caterpillars, sequential spot markings are often observed and used for aposematic colouration. In contrast to adult wings, caterpillar cuticle markings are repeatedly generated at each moult, but little is known about how the patterns are formed and maintained periodically. Here we focus on a silkworm mutant, multi lunar (L), with twin-spot markings on sequential segments. Positional cloning of L and expression analyses reveal that cis-regulatory change in Wnt1 is responsible for the spot patterning. The periodical upregulation of Wnt1 in response to ecdysteroid is detected only in epidermis within spot marking area. We verify by transgenic expression that the ectopic Wnt1 induces the additional pigmentation. Furthermore, the association of Wnt1 expression with spot markings is observed in the wild Bombyx species and swallowtail butterfly Papilio machaon. Taken together, we anticipate that periodic Wnt1 expression may contribute to natural variations of spot patterning on caterpillar cuticle.

  8. Unsteady Flow of Radiating and Chemically Reacting MHD Micropolar Fluid in Slip-Flow Regime with Heat Generation

    NASA Astrophysics Data System (ADS)

    Abo-Dahab, S. M.; Mohamed, R. A.

    2013-11-01

    An analytical study of the problem of unsteady free convection with thermal radiation and heat generation on MHD micropolar fluid flow through a porous medium bounded by a semi-infinite vertical plate in a slip-flow regime has been presented. The Rosseland diffusion approximation is used to describe the radiation heat flux in the energy equation. The homogeneous chemical reaction of first order is accounted for in the mass diffusion equation. A uniform magnetic field acts perpendicular on the porous surface absorbing micropolar fluid with a suction velocity varying with time. A perturbation technique is applied to obtain the expressions for the velocity, microrotation, temperature, and concentration distributions. Expressions for the skin-friction, Nusselt number, and Sherwood number are also obtained. The results are discussed graphically for different values of the parameters entered into the equations of the problem.

  9. Characterization of open-cycle coal-fired MHD generators. 14th/15th quarterly technical progress report, February 1-July 31, 1980

    SciTech Connect

    Wormhoudt, J.; Yousefian, V.; Weinberg, M.; Kolb, C.; Martinez-Sanchez, M.; Cheng, W.; Bien, F.; Dvore, D.; Unkel, W.; Stewart, G.

    1980-09-01

    The successful design of full-scale, open-cycle, coal-fired MHD generators for baseload electrical production requires a detailed understanding of the plasma chemical and plasma dynamic characteristics of anticipated combustor and channel fluids. Progress in efforts to model the efficiency of an open-cycle, coal-fired MHD channel based on the characterization of the channel flow as well as laboratory experiments to validate the modeling effort as detailed. In addition, studies related to understanding arcing phenomena in the vicinity of an anode are reported.

  10. Characterization of open-cycle coal-fired MHD generators. 16th quarterly technical progress report, December 16, 1980-March 31, 1981

    SciTech Connect

    Wormhoudt, J.; Yousefian, V.; Weinberg, M.; Kolb, C.; Martinez-Sanchez, M.; Cheng, W.; Dvore, D.; Freedman, A.; Stanton, A.; Stewart, G.

    1981-05-01

    The successful design of full-scale, open-cycle, coal-fired MHD generators for baseload electrical production requires a detailed understanding of the plasma chemical and plasma dynamic characteristics of anticipated combustor and channel fluids. Progress in efforts to model the efficiency of an open-cycle, coal-fired MHD channel based on the characterization of the channel flow as well as laboratory experiments to validate the modeling effort is reported. In addition, studies related to understanding arcing and corrosion phenomena in the vicinity of an anode are reported.

  11. Generation of the V4.2m5 and AMPX and MPACT 51 and 252-Group Libraries with ENDF/B-VII.0 and VII.1

    SciTech Connect

    Kim, Kang Seog

    2016-12-12

    The evaluated nuclear data file (ENDF)/B-7.0 v4.1m3 MPACT 47-group library has been used as a main library for the Consortium for Advanced Simulation of Light Water Reactors (CASL) neutronics simulator in simulating pressurized water reactor (PWR) problems. Recent analysis for the high void boiling water reactor (BWR) fuels and burnt fuels indicates that the 47-group library introduces relatively large reactivity bias. Since the 47- group structure does not match with the SCALE 6.2 252-group boundaries, the CASL Virtual Environment for Reactor Applications Core Simulator (VERA-CS) MPACT library must be maintained independently, which causes quality assurance concerns. In order to address this issue, a new 51-group structure has been proposed based on the MPACT 47- g and SCALE 252-g structures. In addition, the new CASL library will include a 19-group structure for gamma production and interaction cross section data based on the SCALE 19- group structure. New AMPX and MPACT 51-group libraries have been developed with the ENDF/B-7.0 and 7.1 evaluated nuclear data. The 19-group gamma data also have been generated for future use, but they are only available on the AMPX 51-g library. In addition, ENDF/B-7.0 and 7.1 MPACT 252-g libraries have been generated for verification purposes. Various benchmark calculations have been performed to verify and validate the newly developed libraries.

  12. MHD boundary layer radiative, heat generating and chemical reacting flow past a wedge moving in a nanofluid.

    PubMed

    Khan, Md Shakhaoath; Karim, Ifsana; Islam, Md Sirajul; Wahiduzzaman, Mohammad

    2014-01-01

    The present study analyzed numerically magneto-hydrodynamics (MHD) laminar boundary layer flow past a wedge with the influence of thermal radiation, heat generation and chemical reaction. This model used for the momentum, temperature and concentration fields. The principal governing equations is based on the velocity uw (x) in a nanofluid and with a parallel free stream velocity ue (x) and surface temperature and concentration. Similarity transformations are used to transform the governing nonlinear boundary layer equations for momentum, thermal energy and concentration to a system of nonlinear ordinary coupled differential equations with fitting boundary conditions. The transmuted model is shown to be controlled by a number of thermo-physical parameters, viz. the magnetic parameter, thermal convective parameter, mass convective parameter, radiation-conduction parameter, heat generation parameter, Prandtl number, Lewis number, Brownian motion parameter, thermophoresis parameter, chemical reaction parameter and pressure gradient parameter. Numerical elucidations are obtained with the legendary Nactsheim-Swigert shooting technique together with Runge-Kutta six order iteration schemes. Comparisons with previously published work are accomplished and proven an excellent agreement.

  13. MHD boundary layer radiative, heat generating and chemical reacting flow past a wedge moving in a nanofluid

    NASA Astrophysics Data System (ADS)

    Khan, Md Shakhaoath; Karim, Ifsana; Islam, Md Sirajul; Wahiduzzaman, Mohammad

    2014-07-01

    The present study analyzed numerically magneto-hydrodynamics (MHD) laminar boundary layer flow past a wedge with the influence of thermal radiation, heat generation and chemical reaction. This model used for the momentum, temperature and concentration fields. The principal governing equations is based on the velocity u w (x) in a nanofluid and with a parallel free stream velocity u e (x) and surface temperature and concentration. Similarity transformations are used to transform the governing nonlinear boundary layer equations for momentum, thermal energy and concentration to a system of nonlinear ordinary coupled differential equations with fitting boundary conditions. The transmuted model is shown to be controlled by a number of thermo-physical parameters, viz. the magnetic parameter, thermal convective parameter, mass convective parameter, radiation-conduction parameter, heat generation parameter, Prandtl number, Lewis number, Brownian motion parameter, thermophoresis parameter, chemical reaction parameter and pressure gradient parameter. Numerical elucidations are obtained with the legendary Nactsheim-Swigert shooting technique together with Runge-Kutta six order iteration schemes. Comparisons with previously published work are accomplished and proven an excellent agreement.

  14. Closed cycle MHD power generation experiments using a helium-cesium working fluid in the NASA Lewis Facility

    NASA Technical Reports Server (NTRS)

    Sovie, R. J.

    1976-01-01

    The MHD channel in the NASA Lewis Research Center was redesigned and used in closed cycle power generation experiments with a helium-cesium working fluid. The cross sectional dimensions of the channel were reduced to 5 by 16.5 cm to allow operation over a variety of conditions. Experiments have been run at temperatures of 1900-2100 K and Mach numbers from 0.3 to 0.55 in argon and 0.2 in helium. Improvements in Hall voltage isolation and seed vaporization techniques have resulted in significant improvements in performance. Typical values obtained with helium are Faraday open circuit voltage 141 V (92% of uBh) at a magnetic field strength of 1.7 T, power outputs of 2.2 kw for tests with 28 electrodes and 2.1 kw for tests with 17 electrodes. Power densities of 0.6 MW/cu m and Hall fields of about 1100 V/m were obtained in the tests with 17 electrodes, representing a factor of 18 improvement over previously reported results. The V-I curves and current distribution data indicate that while near ideal equilibrium performance is obtained under some conditions, no nonequilibrium power has been generated to date.

  15. MHD Spectroscopy

    SciTech Connect

    Heeter, R F; Fasoli, A; Testa, D; Sharapov, S; Berk, H L; Breizman, B; Gondhalekar, A; Mantsinen, M

    2004-03-23

    Experiments are conducted on the JET tokamak to assess the diagnostic potential of MHD active and passive spectroscopy, for the plasma bulk and its suprathermal components, using Alfv{acute e}n Eigenmodes (AEs) excited by external antennas and by energetic particles. The measurements of AE frequencies and mode numbers give information on the bulk plasma. Improved equilibrium reconstruction, in particular in terms of radial profiles of density and safety factor, is possible from the comparison between the antenna driven spectrum and that calculated theoretically. Details of the time evolution of the non-monotonic safety factor profile in advanced scenarios can be reconstructed from the frequency of ICRH-driven energetic particle modes. The plasma effective mass can be inferred from the resonant frequency of externally driven AEs in discharges with similar equilibrium profiles. The stability thresholds and the nonlinear development of the instabilities can give clues on energy and spatial distribution of the fast particle population. The presence of unstable AEs provides lower limits in the energy of ICRH generated fast ion tails. Fast ion pressure gradients and their evolution can be inferred from the stability of AEs at different plasma radial positions. Finally, the details of the AE spectrum in the nonlinear stage can be used to obtain information about the fast particle velocity space diffusion.

  16. Visualization analysis of tiger-striped flow mark generation phenomena in injection molding

    NASA Astrophysics Data System (ADS)

    Owada, Shigeru; Yokoi, Hidetoshi

    2016-03-01

    The generation mechanism of tiger-striped flow marks of polypropylene (PP)/rubber/talc blends in injection molding was investigated by dynamic visualization analysis in a glass-inserted mold. The analysis revealed that the behavior of the melt flow front correlates with the flow mark generation. The cloudy part in the tiger-striped flow marks corresponded to the low transcription rate area of the melt diverging near the cavity wall, while the glossy part corresponded to the high transcription rate area of the melt converging toward the cavity wall side. The melt temperature at the high transcription rate area was slightly lower than that at the low transcription rate area. These phenomena resulted due to the difference in the temperature of the melt front that was caused by the asymmetric fountain flow. These results suggest the followings; At the moment when the melt is broken near the one side of cavity wall due to piling the extensional strains up to a certain level, the melt spurts out near the broken side. It results in generating asymmetric fountain flow temporarily to relax the extensional front surface, which moves toward the opposite side to form the high transcription area.

  17. Magnetohydrodynamic power generation

    NASA Technical Reports Server (NTRS)

    Smith, J. L.

    1984-01-01

    Magnetohydrodynamic (MHD) Power Generation is a concise summary of MHD theory, history, and future trends. Results of the major international MHD research projects are discussed. Data from MHD research is included. Economics of initial and operating costs are considered.

  18. Analyses on the Ionization Instability of Non-Equilibrium Seeded Plasma in an MHD Generator

    NASA Astrophysics Data System (ADS)

    Le, Chi Kien

    2016-06-01

    Recently, closed cycle magnetohydrodynamic power generation system research has been focused on improving the isentropic efficiency and the enthalpy extraction ratio. By reducing the cross-section area ratio of the disk magnetohydrodynamic generator, it is believed that a high isentropic efficiency can be achieved with the same enthalpy extraction. In this study, the result relating to a plasma state which takes into account the ionization instability of non-equilibrium seeded plasma is added to the theoretical prediction of the relationship between enthalpy extraction and isentropic efficiency. As a result, the electron temperature which reaches the seed complete ionization state without the growth of ionization instability can be realized at a relatively high seed fraction condition. However, the upper limit of the power generation performance is suggested to remain lower than the value expected in the low seed fraction condition. It is also suggested that a higher power generation performance may be obtained by implementing the electron temperature range which reaches the seed complete ionization state at a low seed fraction.

  19. Simulating forensic casework scenarios in experimental studies: The generation of footwear marks in blood.

    PubMed

    McElhone, Rachel L; Meakin, Georgina E; French, James C; Alexander, Tracy; Morgan, Ruth M

    2016-07-01

    A study was designed to investigate the effects of external variables, including blood type, flooring surface, footwear tread depth and blood dryness, on the appearance of blood-based footwear marks, with particular reference to simulating a specific casework scenario. Results showed that footwear marks left in human blood tended to be of greater quality than those in equine blood, highlighting a potential issue in applying data generated with equine blood to human bloodstains in casework. Footwear tread effects were also dependent on blood type, but the type of flooring surface did not affect the appearance of the mark. Under some conditions, as the blood dried, the amount of detail retained from footwear contact decreased. These results provide the beginnings of an empirical evidence base to allow a more accurate interpretation of blood-based footwear marks in forensic casework. When applied to a disputed bloodstain in a specific case, these results also demonstrate the importance of such experiments in narrowing the range of explanations possible in the interpretation of forensic evidence.

  20. Numerical investigation of entropy generation in unsteady MHD generalized Couette flow with variable electrical conductivity.

    PubMed

    Chinyoka, T; Makinde, O D

    2013-01-01

    The thermodynamic second law analysis is utilized to investigate the inherent irreversibility in an unsteady hydromagnetic generalized Couette flow with variable electrical conductivity in the presence of induced electric field. Based on some simplified assumption, the model nonlinear governing equations are obtained and solved numerically using semidiscretization finite difference techniques. Effects of various thermophysical parameters on the fluid velocity, temperature, current density, skin friction, the Nusselt number, entropy generation number, and the Bejan number are presented graphically and discussed quantitatively.

  1. Male germline transmits fetal alcohol epigenetic marks for multiple generations: a review.

    PubMed

    Sarkar, Dipak K

    2016-01-01

    Alcohol exposure during fetal and early postnatal development can lead to an increased incidence of later life adult-onset diseases. Examples include central nervous system dysfunction, depression, anxiety, hyperactivity, and an inability to deal with stressful situations, increased infection and cancer. Direct effects of alcohol leading to developmental abnormalities often involve epigenetic modifications of genes that regulate cellular functions. Epigenetic marks carried over from the parents are known to undergo molecular programming events that happen early in embryonic development by a wave of DNA demethylation, which leaves the embryo with a fresh genomic composition. The proopiomelanocortin (Pomc) gene controls neuroendocrine-immune functions and is imprinted by fetal alcohol exposure. Recently, this gene has been shown to be hypermethylated through three generations. Additionally, the alcohol epigenetic marks on the Pomc gene are maintained in the male but not in the female germline during this transgenerational transmission. These data suggest that the male-specific chromosome might be involved in transmitting alcohol epigenetic marks through multiple generations.

  2. Non-planar MHD model for solar flare-generated disturbances in the heliospheric equatorial plane

    NASA Technical Reports Server (NTRS)

    Wu, S. T.; Dryer, M.; Han, S. M.

    1983-01-01

    An analysis, with a representative (canonical) example of solar-flare-generated equatorial disturbances, is made for the temporal and spatial changes in the solar wind plasma and magnetic field environment between the sun and 1 AU. The goal is to search for first-order global consequences rather than to make a parametric study. The analysis treats all three plasma velocity and magnetic field components in any convenient heliospheric plane of symmetry. The representative disturbance is examined for the canonical case in which the temporal and spatial changes in a homogeneous solar wind caused by a solar-flare-generated shock wave are described. All plasma and field parameters at three radial locations are examined. These are the central meridian and 33 deg W and 90 deg W of the flare's central meridian. It is found that the incorporation of a small meridional magnetic field in the ambient magnetic spiral field has negligible effect on the results. The magnetic field exhibits strong kinking within the interplanetary shocked flow, even reversed polarity that, coupled with low temperature and low density, suggests a plausible explanation for magnetic clouds' with accompanying double-streaming of electrons observed at directions approximately 90 deg to the heliocentric radius.

  3. Congenital deficiency of factor VII.

    PubMed

    Sikka, M; Gomber, S; Madan, N; Rusia, U; Sharma, S

    1996-01-01

    A case of congenital factor VII deficiency in a five-year-old child is reported. The patient, born of a non-consanguineous marriage, presented with repeated bouts of epistaxis since childhood. The prothrombin time (PT) was markedly prolonged with a normal bleeding time (BT), partial thromboplastin time with Kaolin (PTTK) and platelet count. The patient has been on follow up for the last four years and is doing apparently well.

  4. Factor VII deficiency

    MedlinePlus

    ... if one or more of these factors are missing or are not functioning like they should. Factor VII is one such coagulation factor. Factor VII deficiency runs in families (inherited) and is very rare. Both parents must ...

  5. Polar Cap Potential Saturation during the Bastille Day Storm using Next Generation Magnetosphere-Ionosphere Coupling Global MHD Simulation

    NASA Astrophysics Data System (ADS)

    Kubota, Y.; Nagatsuma, T.; Den, M.; Tanaka, T.; Fujita, S.

    2015-12-01

    We are developing a real-time numerical simulator for the solar-wind-magnetosphere-ionosphere coupling system using next generation magnetosphere-ionosphere coupling global MHD simulation called REPPU (REProduce Plasma Universe) code. The feature of simulation has an advanced robustness to strong solar wind case because a triangular grid is used, which is able to calculate in the uniform accuracy over the whole region. Therefore we can simulate extreme event such as the Bastille day storm. The resolution is 7682 grids in the horizontal direction and 240 grids in the radial direction. The inner boundary of the simulation box is set at 2.6 Re. We investigate the reproduction of the magnetosphere-ionosphere coupling simulation in strong solar wind case. Therefore we compared the simulation results with the observation of the Bastille day storm event (2000/7/15), in which the solar wind velocity is above 1000 km/s and the value of Bz reached -60 nT. Especially, we focus the cross polar cap potential (CPCP) saturation and time variation because the CPCP represents the value of magnetospheric - ionospheric convection strength via region 1 current. The CPCP depends on solar wind electric field, dynamic pressure and ionospheric conductivity [Siscoe et al., 2002; Kivelson et al., 2008]. The model of Kivelson et al. [2008] shows a good reproduction to the CPCP variation. However their study assumes that the ionospheric conductivity is constant. The conductivity in our simulation of the Bastille day event is varied by the auroral activity. In this lecture, we discuss the effect of both the auroral conductance and solar EUV-driven conductance to CPCP saturation.

  6. Development of Liquid-Vapor Core Reactors with MHD Generator for Space Power and Propulsion Applications

    SciTech Connect

    Samim Anghaie

    2002-08-13

    Any reactor that utilizes fuel consisting of a fissile material in a gaseous state may be referred to as a gaseous core reactor (GCR). Studies on GCRs have primarily been limited to the conceptual phase, mostly due to budget cuts and program cancellations in the early 1970's. A few scientific experiments have been conducted on candidate concepts, primarily of static pressure fissile gas filling a cylindrical or spherical cavity surrounded by a moderating shell, such as beryllium, heavy water, or graphite. The main interest in this area of nuclear power generation is for space applications. The interest in space applications has developed due to the promise of significant enhancement in fuel utilization, safety, plant efficiency, special high-performance features, load-following capabilities, power conversion optimization, and other key aspects of nuclear power generation. The design of a successful GCR adapted for use in space is complicated. The fissile material studied in the pa st has been in a fluorine compound, either a tetrafluoride or a hexafluoride. Both of these molecules have an impact on the structural material used in the making of a GCR. Uranium hexafluoride as a fuel allows for a lower operating temperature, but at temperatures greater than 900K becomes essentially impossible to contain. This difficulty with the use of UF6 has caused engineers and scientists to use uranium tetrafluoride, which is a more stable molecule but has the disadvantage of requiring significantly higher operating temperatures. Gas core reactors have traditionally been studied in a steady state configuration. In this manner a fissile gas and working fluid are introduced into the core, called a cavity, that is surrounded by a reflector constructed of materials such as Be or BeO. These reactors have often been described as cavity reactors because the density of the fissile gas is low and criticality is achieved only by means of the reflector to reduce neutron leakage from the core

  7. Corrosion and arc erosion in MHD channels

    SciTech Connect

    Rosa, R.J. . Dept. of Mechanical Engineering); Pollina, R.J. . Dept. of Mechanical Engineering EG and G Energy Measurements, Inc., Las Vegas, NV )

    1992-08-01

    The problems connected with gas side corrosion for the design of the lA4 (POC) channel hardware are explored and results of gas side wear rate tests in the Textron Mark VII facility are presented. It is shown that the proposed designs meet a 2000 hour lifetime criterion based upon these materials tests. Improvement in cathode lifetime is demonstrated with lower voltage intercathode gaps. The corrosion of these materials is discussed and it is shown how lifetimes are dependent upon gap voltage and average metal temperature. The importance of uniformity of slagging to the durability of the anode wall is demonstrated. The wear mechanism of the anodes in the MHD channel is analyzed. In addition to gas-side corrosion, the results of specific water corrosion tests of sidewall materials are discussed. All of the tests reported here were carried out to confirm the gas-side performance and the manufacturability of anode and sidewall designs and to address questions posed about the durability of tungsten-copper on the waterside. the results of water corrosion tests of the tungsten copper alloy sidewall material are presented to show that with proper control of waterside pH and, if necessary, dissolved oxygen, one can obtain reliable performance with no degradation of heat transfer with this material. The final choice of materials was determined primarily by the outcome of these tests and also by the question of the manufacturability of the prospective designs.

  8. Arbitrary continuous nano-marks generated by multifocal spot arrays for controllable laser printing

    NASA Astrophysics Data System (ADS)

    Wen, Jing; Feng, Hui; Liu, Shiliang; Zhang, Dawei

    2017-04-01

    Phase-only modulations derived from the Debye approximation of the Richards–Wolf vectorial integral are used to produce a multifocal spot array. An analytical solution, which controls the position of each focal spot, can generate phase modulation images which are loaded into spatial light modulators. The calculated field distributions and the experimental images of the spot array on the back aperture of the objective are both demonstrated and validated. By overlapping the discrete focal points, continuous nano-structures of arbitrary marks can be achieved conveniently and easily. The above-proposed approach offers opportunities for flexible laser printing and creative micro-manipulation in the future.

  9. MHD channel performance for potential early commercial MHD power plants

    NASA Technical Reports Server (NTRS)

    Swallom, D. W.

    1981-01-01

    The commercial viability of full and part load early commercial MHD power plants is examined. The load conditions comprise a mass flow of 472 kg/sec in the channel, Rosebud coal, 34% by volume oxygen in the oxidizer preheated to 922 K, and a one percent by mass seeding with K. The full load condition is discussed in terms of a combined cycle plant with optimized electrical output by the MHD channel. Various electrical load parameters, pressure ratios, and magnetic field profiles are considered for a baseload MHD generator, with a finding that a decelerating flow rate yields slightly higher electrical output than a constant flow rate. Nominal and part load conditions are explored, with a reduced gas mass flow rate and an enriched oxygen content. An enthalpy extraction of 24.6% and an isentropic efficiency of 74.2% is predicted for nominal operation of a 526 MWe MHD generator, with higher efficiencies for part load operation.

  10. MHD channel development, part 3

    NASA Astrophysics Data System (ADS)

    1989-12-01

    This is the final report of work performed by Avco Research Laboratory, Inc. for the U.S. Department of Energy, Pittsburgh Energy Technology Center. The overall objectives of this program were: to contribute, by appropriate systematic experimental and analytical investigations, to the engineering data base necessary for the design and construction of MHD generators at the 50 MW(sub th) and ultimately at commercial sizes; and to design and fabricate specific hardware items to be tested at a site to be specified by DOE. Section 3.0, MHD Channel Design and Performance, reports experimental and analytical investigations related to MHD channel design and performance.

  11. Rapporteur report: MHD electric power plants

    NASA Technical Reports Server (NTRS)

    Seikel, G. R.

    1980-01-01

    Five US papers from the Proceedings of the Seventh International Conference on MHD Electrical Power Generation at the Massachusetts Institute of Technology are summarized. Results of the initial parametric phase of the US effort on the study of potential early commercial MHD plants are reported and aspects of the smaller commercial prototype plant termed the Engineering Test Facility are discussed. The alternative of using a disk geometry generator rather than a linear generator in baseload MHD plants is examined. Closed-cycle as well as open-cycle MHD plants are considered.

  12. Non-linear heat and mass transfer in a MHD Homann nanofluid flow through a porous medium with chemical reaction, heat generation and uniform inflow

    NASA Astrophysics Data System (ADS)

    EL-Dabe, N. T.; Attia, H. A.; Essawy, M. A. I.; Ramadan, A. A.; Abdel-Hamid, A. H.

    2016-11-01

    The steady MHD axisymmetric flow of an incompressible viscous electrically conducting nanofluid impinging on a permeable plate is investigated with heat and mass transfer. An external uniform magnetic field as well as a uniform inflow, in the presence of either suction or injection, are applied normal to the plate. The effects of heat (generation/absorption) and chemical reaction have been accentuated. This study indicates the incorporated influence of both the thermophoresis phenomenon and the Brownian behavior. Numerical solutions for the governing non-linear momentum, energy and nanoparticle equations have been obtained. The rates of heat and mass transfer are presented and discussed.

  13. Effects of thermophoresis and heat generation/absorption on MHD flow due to an oscillatory stretching sheet with chemically reactive species

    NASA Astrophysics Data System (ADS)

    Sheikh, Mariam; Abbas, Zaheer

    2015-12-01

    The effects of chemical reaction and heat generation/absorption on MHD flow over an oscillatory stretching surface in a viscous fluid have been studied in the presence of thermophoresis. The porous plate is oscillated back and forth in its own plane and suction/injection is also taking into account. The similarity solution of the developed non-linear governing partial differential equations is constructed in the form of series using homotopy analysis method. The convergence of the obtained series solutions is discussed in the whole domain (0 ≤ η ≤ ∞) . A parametric study of the all governing parameters is accomplished and the physical results are shown graphically.

  14. MHD Energy Bypass Scramjet Engine

    NASA Technical Reports Server (NTRS)

    Mehta, Unmeel B.; Bogdanoff, David W.; Park, Chul; Arnold, Jim (Technical Monitor)

    2001-01-01

    Revolutionary rather than evolutionary changes in propulsion systems are most likely to decrease cost of space transportation and to provide a global range capability. Hypersonic air-breathing propulsion is a revolutionary propulsion system. The performance of scramjet engines can be improved by the AJAX energy management concept. A magneto-hydro-dynamics (MHD) generator controls the flow and extracts flow energy in the engine inlet and a MHD accelerator downstream of the combustor accelerates the nozzle flow. A progress report toward developing the MHD technology is presented herein. Recent theoretical efforts are reviewed and ongoing experimental efforts are discussed. The latter efforts also include an ongoing collaboration between NASA, the US Air Force Research Laboratory, US industry, and Russian scientific organizations. Two of the critical technologies, the ionization of the air and the MHD accelerator, are briefly discussed. Examples of limiting the combustor entrance Mach number to a low supersonic value with a MHD energy bypass scheme are presented, demonstrating an improvement in scramjet performance. The results for a simplified design of an aerospace plane show that the specific impulse of the MHD-bypass system is better than the non-MHD system and typical rocket over a narrow region of flight speeds and design parameters. Equilibrium ionization and non-equilibrium ionization are discussed. The thermodynamic condition of air at the entrance of the engine inlet determines the method of ionization. The required external power for non-equilibrium ionization is computed. There have been many experiments in which electrical power generation has successfully been achieved by magneto-hydrodynamic (MHD) means. However, relatively few experiments have been made to date for the reverse case of achieving gas acceleration by the MHD means. An experiment in a shock tunnel is described in which MHD acceleration is investigated experimentally. MHD has several

  15. Evaluation of technical feasibility of closed-cycle non-equilibrium MHD power generation with direct coal firing. Final report, Task 1

    SciTech Connect

    Not Available

    1981-11-01

    Program accomplishments in a continuing effort to demonstrate the feasibility of direct coal fired, closed cycle, magnetohydrodynamic power generation are detailed. These accomplishments relate to all system aspects of a CCMHD power generation system including coal combustion, heat transfer to the MHD working fluid, MHD power generation, heat and cesium seed recovery and overall systems analysis. Direct coal firing of the combined cycle has been under laboratory development in the form of a high slag rejection, regeneratively air cooled cyclone coal combustor concept, originated within this program. A hot bottom ceramic regenerative heat exchanger system was assembled and test fired with coal for the purposes of evaluating the catalytic effect of alumina on NO/sub x/ emission reduction and operability of the refractory dome support system. Design, procurement, fabrication and partial installation of a heat and seed recovery flow apparatus was accomplished and was based on a stream tube model of the full scale system using full scale temperatures, tube sizes, rates of temperature change and tube geometry. Systems analysis capability was substantially upgraded by the incorporation of a revised systems code, with emphasis on ease of operator interaction as well as separability of component subroutines. The updated code was used in the development of a new plant configuration, the Feedwater Cooled (FCB) Brayton Cycle, which is superior to the CCMHD/Steam cycle both in performance and cost. (WHK)

  16. A comparative study between xerographic, computer-assisted overlay generation and animated-superimposition methods in bite mark analyses.

    PubMed

    Tai, Meng Wei; Chong, Zhen Feng; Asif, Muhammad Khan; Rahmat, Rabiah A; Nambiar, Phrabhakaran

    2016-09-01

    This study was to compare the suitability and precision of xerographic and computer-assisted methods for bite mark investigations. Eleven subjects were asked to bite on their forearm and the bite marks were photographically recorded. Alginate impressions of the subjects' dentition were taken and their casts were made using dental stone. The overlays generated by xerographic method were obtained by photocopying the subjects' casts and the incisal edge outlines were then transferred on a transparent sheet. The bite mark images were imported into Adobe Photoshop® software and printed to life-size. The bite mark analyses using xerographically generated overlays were done by comparing an overlay to the corresponding printed bite mark images manually. In computer-assisted method, the subjects' casts were scanned into Adobe Photoshop®. The bite mark analyses using computer-assisted overlay generation were done by matching an overlay and the corresponding bite mark images digitally using Adobe Photoshop®. Another comparison method was superimposing the cast images with corresponding bite mark images employing the Adobe Photoshop® CS6 and GIF-Animator©. A score with a range of 0-3 was given during analysis to each precision-determining criterion and the score was increased with better matching. The Kruskal Wallis H test showed significant difference between the three sets of data (H=18.761, p<0.05). In conclusion, bite mark analysis using the computer-assisted animated-superimposition method was the most accurate, followed by the computer-assisted overlay generation and lastly the xerographic method. The superior precision contributed by digital method is discernible despite the human skin being a poor recording medium of bite marks.

  17. MHD channel development, part 4

    NASA Astrophysics Data System (ADS)

    1989-12-01

    This is the final report of work performed by Avco Research Laboratory, Inc. for the U.S. Department of Energy, Pittsburgh Energy Technology Center. The overall objectives of this program were: to contribute, by appropriate systematic experimental and analytical investigations, to the engineering data base necessary for the design and construction of MHD generators at the 50 MW(sub th) and ultimately at commercial sizes; and to design and fabricate specific hardware items to be tested at a site to be specified by DOE. The program consisted of a series of related tasks, which are described in subsequent sections of this report. Section 4.0, MHD Channel Construction and Lifetime, reports experimental investigations related to MHD channel reliability and lifetime, where the principal aim is to improve the constructability, maintainability, and reliability of coal-fired, long-duration MHD channels.

  18. MHD turbulent processes

    NASA Technical Reports Server (NTRS)

    Montgomery, David

    1988-01-01

    Three areas of study in MHD turbulence are considered. These are the turbulent relaxation of the toroidal Z pinch, density fluctuations in MHD fluids, and MHD cellular automata. A Boolean computer game that updates a cellular representation in parallel and that has macroscopic averages converging to solutions of the two-dimensional MHD equations is discussed.

  19. Virtual tool mark generation for efficient striation analysis in forensic science

    SciTech Connect

    Ekstrand, Laura

    2012-01-01

    In 2009, a National Academy of Sciences report called for investigation into the scienti c basis behind tool mark comparisons (National Academy of Sciences, 2009). Answering this call, Chumbley et al. (2010) attempted to prove or disprove the hypothesis that tool marks are unique to a single tool. They developed a statistical algorithm that could, in most cases, discern matching and non-matching tool marks made at di erent angles by sequentially numbered screwdriver tips. Moreover, in the cases where the algorithm misinterpreted a pair of marks, an experienced forensics examiner could discern the correct outcome. While this research served to con rm the basic assumptions behind tool mark analysis, it also suggested that statistical analysis software could help to reduce the examiner's workload. This led to a new tool mark analysis approach, introduced in this thesis, that relies on 3D scans of screwdriver tip and marked plate surfaces at the micrometer scale from an optical microscope. These scans are carefully cleaned to remove noise from the data acquisition process and assigned a coordinate system that mathematically de nes angles and twists in a natural way. The marking process is then simulated by using a 3D graphics software package to impart rotations to the tip and take the projection of the tip's geometry in the direction of tool travel. The edge of this projection, retrieved from the 3D graphics software, becomes a virtual tool mark. Using this method, virtual marks are made at increments of 5 and compared to a scan of the evidence mark. The previously developed statistical package from Chumbley et al. (2010) performs the comparison, comparing the similarity of the geometry of both marks to the similarity that would occur due to random chance. The resulting statistical measure of the likelihood of the match informs the examiner of the angle of the best matching virtual mark, allowing the examiner to focus his/her mark analysis on a smaller range of angles

  20. Three-dimensional, time-dependent, MHD model of a solar flare-generated interplanetary shock wave

    NASA Technical Reports Server (NTRS)

    Dryer, M.; Wu, S. T.; Han, S. M.

    1986-01-01

    A three-dimensional time-dependent MHD model of the propagation of an interplanetary shock wave into an ambient three-dimensional heliospheric solar wind is initialized with a peak velocity of 1000 km/s at the center of a right circular cone of 18 deg included angle at 18 solar radii. Differences from a previous 2-1/2 simulation (Wu et al., 1983; Gislason et al., 1984; Dryer et al., 1984) include diminuation of the solar peak velocity and concentration of the peak density at each radius. The IMF magnitude starts with high-latitude peaks, and helical-like IMF rotation is noted due to a large-amplitude nonlinear Alfven wave in the shocked plasma.

  1. Simultaneous effects of heat generation/absorption and thermal radiation in magnetohydrodynamics (MHD) flow of Maxwell nanofluid towards a stretched surface

    NASA Astrophysics Data System (ADS)

    Hayat, Tasawar; Qayyum, Sajid; Shehzad, Sabir Ali; Alsaedi, Ahmed

    Mathematical analysis of magnetohydrodynamic (MHD) three-dimensional nonlinear convective flow of Maxwell nanofluid towards a stretching surface is made in this article. Characteristics of heat transfer are examined under thermal radiation, heat generation/absorption and prescribed heat flux condition. Nanofluid model includes Brownian motion and thermophoresis. Dimensional nonlinear expressions of momentum, energy and concentration are converted into dimensionless systems by invoking suitable similarity variables. A well-known homotopic technique is implemented for dimensionless expressions. Impact of different quantities on velocities, temperature and concentration are scrutinized graphically and discussed in detail. The expressions of Nusselt and Sherwood numbers are calculated and addressed comprehensively. It is also seen that thermal radiation parameter enhances the temperature field and heat transfer rate.

  2. Homosexuals and Title VII

    ERIC Educational Resources Information Center

    Rivera, Juan R.; Galvan, Richard J.

    1975-01-01

    A method of dealing with the problems of discrimination against homosexuals in private employment through the application of Title VII of the Civil Rights Act of 1964 is discussed. The scope of the paper is limited to male homosexuals. (LBH)

  3. Fokker D.VII

    NASA Technical Reports Server (NTRS)

    1923-01-01

    Fokker D.VII: The Fokker D.VII was one of the best fighter aircraft of World War I, and was the only weapon used by the Central Powers specifically mentioned in the Versailles Treaty. The Central Powers surrendered 142 at the close of the war, and the Fokker company sold even more to the U. S. Air Service. Several were flown at Langley Field, but this one was the sole example operated by the NACA.

  4. Closed cycle MHD power generation experiments using a helium-cesium working fluid in the NASA Lewis Facility

    NASA Technical Reports Server (NTRS)

    Sovie, R. J.

    1976-01-01

    A MHD channel, which was previously operated for over 500 hours of thermal operation, ten thermal cycles, and 200 cesium injection tests, was removed from the facility and redesigned. The cross sectional dimensions of the channel were reduced to 5 by 16.5 cm to allow operation over a variety of conditions. The redesigned channel has been operated for well over 300 hours, 10 thermal cycles, and 150 cesium injection tests with no problems. Experiments have been run at temperatures of 1900-2100 K and Mach numbers from 0.3 to 0.55 in argon and 0.2 in helium. The best results to date have been obtained in the helium tests. Power outputs of 2.2 kw for tests with 28 electrodes and 2.1 kw for tests with 17 electrodes were realized. Power densities of 0.6 MW/cu m and Hall fields of about 1,100 V/m were obtained in the tests with 17 electrodes.

  5. Modeling of fast neutral-beam-generated ion effects on MHD-spectroscopic observations of resistive wall mode stability in DIII-D plasmas

    SciTech Connect

    Turco, F. Hanson, J. M.; Navratil, G. A.; Turnbull, A. D.

    2015-02-15

    Experiments conducted at DIII-D investigate the role of drift kinetic damping and fast neutral beam injection (NBI)-ions in the approach to the no-wall β{sub N} limit. Modelling results show that the drift kinetic effects are significant and necessary to reproduce the measured plasma response at the ideal no-wall limit. Fast neutral-beam ions and rotation play important roles and are crucial to quantitatively match the experiment. In this paper, we report on the model validation of a series of plasmas with increasing β{sub N}, where the plasma stability is probed by active magnetohydrodynamic (MHD) spectroscopy. The response of the plasma to an externally applied field is used to probe the stable side of the resistive wall mode and obtain an indication of the proximity of the equilibrium to an instability limit. We describe the comparison between the measured plasma response and that calculated by means of the drift kinetic MARS-K code [Liu et al., Phys. Plasmas 15, 112503 (2008)], which includes the toroidal rotation, the electron and ion drift-kinetic resonances, and the presence of fast particles for the modelled plasmas. The inclusion of kinetic effects allows the code to reproduce the experimental results within ∼13% for both the amplitude and phase of the plasma response, which is a significant improvement with respect to the undamped MHD-only model. The presence of fast NBI-generated ions is necessary to obtain the low response at the highest β{sub N} levels (∼90% of the ideal no-wall limit). The toroidal rotation has an impact on the results, and a sensitivity study shows that a large variation in the predicted response is caused by the details of the rotation profiles at high β{sub N}.

  6. Corrosion and arc erosion in MHD channels. Final report

    SciTech Connect

    Rosa, R.J.; Pollina, R.J. |

    1992-08-01

    The problems connected with gas side corrosion for the design of the lA4 (POC) channel hardware are explored and results of gas side wear rate tests in the Textron Mark VII facility are presented. It is shown that the proposed designs meet a 2000 hour lifetime criterion based upon these materials tests. Improvement in cathode lifetime is demonstrated with lower voltage intercathode gaps. The corrosion of these materials is discussed and it is shown how lifetimes are dependent upon gap voltage and average metal temperature. The importance of uniformity of slagging to the durability of the anode wall is demonstrated. The wear mechanism of the anodes in the MHD channel is analyzed. In addition to gas-side corrosion, the results of specific water corrosion tests of sidewall materials are discussed. All of the tests reported here were carried out to confirm the gas-side performance and the manufacturability of anode and sidewall designs and to address questions posed about the durability of tungsten-copper on the waterside. the results of water corrosion tests of the tungsten copper alloy sidewall material are presented to show that with proper control of waterside pH and, if necessary, dissolved oxygen, one can obtain reliable performance with no degradation of heat transfer with this material. The final choice of materials was determined primarily by the outcome of these tests and also by the question of the manufacturability of the prospective designs.

  7. Theoretical and Experimental Research of Capabilities of MHD Technology to Control Gas Flow with Non-Equilibrium Ionization

    DTIC Science & Technology

    2007-11-02

    experimental research of capabilities of using of MHD technology to control gas flow with non-equilibrium ionization. Cold gas flows will be considered, where...and MHD generator will be developed. Requirements to ionizer, MHD generator and flow parameters at which self- sustained operational mode of ionizer and...MHD generator is realized will be formulated. Possibilities of using of MHD control in gas-dynamical systems will be considered. Traditional use of

  8. A three-dimensional MHD simulation of the interaction of the solar wind with the earth's magnetosphere - The generation of field-aligned currents

    NASA Technical Reports Server (NTRS)

    Ogino, T.

    1986-01-01

    The time-dependent interaction of the solar wind with the earth's magnetosphere is simulated using a three-dimensional MHD model. The bow shock, magnetopause, magnetotail, and plasma sheet of the magnetosphere and Birkeland field-aligned currents that are dependent on the polarity of the z component of the IMF are produced. Twin convection cells and a dawn to dusk electric potential of 30-100 kV are detected at the equator in the magnetosphere. Four types of field-aligned currents are observed: region 1, region 2, dayside magnetopause currents in the dayside cusp region, and the dayside cusp currents for southward IMF. Region 1 and 2 field-aligned currents generated for all IMF conditions are 0.6-1.0 x 10 to the 6th A and 0.15-0.61 x 10 to the 6th A, respectively. The relationship between region 1 currents and field-aligned vorticity, and region 2 currents and pressure gradients are studied. The simulated data are compared with a theoretical analysis of the field-aligned currents and good correlation is observed.

  9. Effects of temperature dependent conductivity and absorptive/generative heat transfer on MHD three dimensional flow of Williamson fluid due to bidirectional non-linear stretching surface

    NASA Astrophysics Data System (ADS)

    Bilal, S.; Khalil-ur-Rehman; Malik, M. Y.; Hussain, Arif; Khan, Mair

    Present work is communicated to identify characteristics of magnetohydrodynamic (MHD) three dimensional boundary layer flow of Williamson fluid confined by a bidirectional stretched surface. Conductivity of working fluid is assumed to be temperature dependent. Generative/absorptive heat transfer is also taken into account. Mathematical model is formulated in the form of partial expressions and then transmuted into ordinary differential equations with the help of newfangled set of similarity transformations. The resulting non-linear differential system of equations is solved numerically with the aid of Runge-Kutta algorithm supported by shooting method. Flow features are exemplified quantitatively through graphs. Scintillating results for friction factor and convective heat transfer are computed and scrutinized tabularly. Furthermore, the accuracy of present results is tested with existing literature and we found an excellent agreement. It is inferred that velocity along x-direction mounts whereas along y-direction depreciates for incrementing values of stretching ratio parameter. Moreover, it is also elucidated that non-linearity index tends to decrement the velocity and thermal distributions of fluid flow.

  10. MHD Integrated Topping Cycle Project

    SciTech Connect

    Not Available

    1992-01-01

    The overall objective of the project is to design and construct prototypical hardware for an integrated MHD topping cycle, and conduct long duration proof-of-concept tests of integrated system at the US DOE Component Development and Integration Facility in Butte, Montana. The results of the long duration tests will augment the existing engineering design data base on MHD power train reliability, availability, maintainability, and performance, and will serve as a basis for scaling up the topping cycle design to the next level of development, an early commercial scale power plant retrofit. The components of the MHD power train to be designed, fabricated, and tested include: A slagging coal combustor with a rated capacity of 50 MW thermal input, capable of operation with an Eastern (Illinois {number sign}6) or Western (Montana Rosebud) coal, a segmented supersonic nozzle, a supersonic MHD channel capable of generating at least 1.5 MW of electrical power, a segmented supersonic diffuser section to interface the channel with existing facility quench and exhaust systems, a complete set of current control circuits for local diagonal current control along the channel, and a set of current consolidation circuits to interface the channel with the existing facility inverter.

  11. Production of MHD fluid

    DOEpatents

    Lacey, James J.; Kurtzrock, Roy C.; Bienstock, Daniel

    1976-08-24

    A hot gaseous fluid of low ash content, suitable for use in open-cycle MHD (magnetohydrodynamic) power generation, is produced by means of a three-stage process comprising (1) partial combustion of a fossil fuel to produce a hot gaseous product comprising CO.sub.2 CO, and H.sub.2 O, (2) reformation of the gaseous product from stage (1) by means of a fluidized char bed, whereby CO.sub.2 and H.sub.2 O are converted to CO and H.sub.2, and (3) combustion of CO and H.sub.2 from stage (2) to produce a low ash-content fluid (flue gas) comprising CO.sub.2 and H.sub.2 O and having a temperature of about 4000.degree. to 5000.degree.F.

  12. The importance of residues 195-206 of human blood clotting factor VII in the interaction of factor VII with tissue factor

    SciTech Connect

    Wildgoose, P.; Kisiel, W.; Kazim, A.L. )

    1990-09-01

    Previous studies indicated that human and bovine factor VII exhibit 71% amino acid sequence identity. In the present study, competition binding experiments revealed that the interaction of human factor VII with cell-surface human tissue factor was not inhibited by 100-fold molar excess of bovine factor VII. This finding indicated that bovine and human factor VII are not structurally homologous in the region(s) where human factor VII interacts with human tissue factor. On this premise, the authors synthesized three peptides corresponding to regions of human factor VII that exhibited marked structural dissimilarity to bovine factor VII; these regions of dissimilarity included residues 195-206, 263-274, and 314-326. Peptide 195-206 inhibited the interaction of factor VII with cell-surface tissue factor and the activation of factor X by a complex of factor VIIa and tissue factor half-maximally at concentrations of 1-2 mM. A structurally rearranged form of peptide 195-206 containing an aspartimide residue inhibited these reactions half-maximally at concentrations of 250-300 {mu}M. In contrast, neither peptide 263-274 nor peptide 314-326, at 2 mM concentration, significantly affected either factor VIIa interaction with tissue factor or factor VIIa-mediated activation of factor X. The data provide presumptive evidence that residues 195-206 of human factor VII are involved in the interaction of human factor VII with the extracellular domain of human tissue factor apoprotein.

  13. Dual solutions of radiative MHD nanofluid flow over an exponentially stretching sheet with heat generation/absorption

    NASA Astrophysics Data System (ADS)

    Naramgari, Sandeep; Sulochana, C.

    2016-01-01

    In this study, we analyzed the heat and mass transfer in thermophoretic radiative hydromagnetic nanofluid flow over an exponentially stretching porous sheet embedded in porous medium with internal heat generation/absorption, viscous dissipation and suction/injection effects. The governing partial differential equations of the flow are converted into nonlinear coupled ordinary differential equations by using similarity transformation. Runge-Kutta-based shooting technique is employed to yield the numerical solutions for the model. The effect of non-dimensional parameters on velocity, temperature and concentration profiles are discussed and presented through graphs. The physical quantities of interest local skin friction coefficient, Nusselt and Sherwood numbers are calculated and presented through tables.

  14. Modeling of fast neutral-beam-generated ion effects on MHD-spectroscopic observations of resistive wall mode stability in DIII-D plasmas [Modeling of fast neutral-beam-generated ion effects on MHD spectroscopic observations of RWM stability in DIII-D plasmas

    DOE PAGES

    Turco, Francesca; Turnbull, Alan D.; Hanson, Jeremy M.; ...

    2015-02-03

    Experiments conducted at DIII-D investigate the role of drift kinetic damping and fast neutral beam injection (NBI)-ions in the approach to the no-wall βN limit. Modelling results show that the drift kinetic effects are significant and necessary to reproduce the measured plasma response at the ideal no-wall limit. Fast neutral-beam ions and rotation play important roles and are crucial to quantitatively match the experiment. In this paper, we report on the model validation of a series of plasmas with increasing βN, where the plasma stability is probed by active magnetohydrodynamic (MHD) spectroscopy. The response of the plasma to an externallymore » applied field is used to probe the stable side of the resistive wall mode and obtain an indication of the proximity of the equilibrium to an instability limit. We describe the comparison between the measured plasma response and that calculated by means of the drift kinetic MARS-K code, which includes the toroidal rotation, the electron and ion drift-kinetic resonances, and the presence of fast particles for the modelled plasmas. The inclusion of kinetic effects allows the code to reproduce the experimental results within ~13% for both the amplitude and phase of the plasma response, which is a significant improvement with respect to the undamped MHD-only model. The presence of fast NBI-generated ions is necessary to obtain the low response at the highest βN levels (~90% of the ideal no-wall limit). Finally, the toroidal rotation has an impact on the results, and a sensitivity study shows that a large variation in the predicted response is caused by the details of the rotation profiles at high βN.« less

  15. Modeling of fast neutral-beam-generated ion effects on MHD-spectroscopic observations of resistive wall mode stability in DIII-D plasmas [Modeling of fast neutral-beam-generated ion effects on MHD spectroscopic observations of RWM stability in DIII-D plasmas

    SciTech Connect

    Turco, Francesca; Turnbull, Alan D.; Hanson, Jeremy M.; Navratil, Gerald A.

    2015-02-03

    Experiments conducted at DIII-D investigate the role of drift kinetic damping and fast neutral beam injection (NBI)-ions in the approach to the no-wall βN limit. Modelling results show that the drift kinetic effects are significant and necessary to reproduce the measured plasma response at the ideal no-wall limit. Fast neutral-beam ions and rotation play important roles and are crucial to quantitatively match the experiment. In this paper, we report on the model validation of a series of plasmas with increasing βN, where the plasma stability is probed by active magnetohydrodynamic (MHD) spectroscopy. The response of the plasma to an externally applied field is used to probe the stable side of the resistive wall mode and obtain an indication of the proximity of the equilibrium to an instability limit. We describe the comparison between the measured plasma response and that calculated by means of the drift kinetic MARS-K code, which includes the toroidal rotation, the electron and ion drift-kinetic resonances, and the presence of fast particles for the modelled plasmas. The inclusion of kinetic effects allows the code to reproduce the experimental results within ~13% for both the amplitude and phase of the plasma response, which is a significant improvement with respect to the undamped MHD-only model. The presence of fast NBI-generated ions is necessary to obtain the low response at the highest βN levels (~90% of the ideal no-wall limit). Finally, the toroidal rotation has an impact on the results, and a sensitivity study shows that a large variation in the predicted response is caused by the details of the rotation profiles at high βN.

  16. Metal/gas MHD conversion

    NASA Astrophysics Data System (ADS)

    Thibault, J. P.; Joussellin, F.; Alemany, A.; Dupas, A.

    1982-09-01

    Operation features, theory, performance, and possible spatial applications of metal/gas MHD electrical generators are described. The working principle comprises an MHD channel, surrounded by a magnet, filled with a molten, highly conductive metal into which gas is pumped. The heat of the metal expands the gas, forcing a flow through the magnetic field crossing the channel, thus creating an electrical current conducted by the metal. The gas and metal are separated by a centrifugal device and both are redirected into the channel, forming thereby a double closed circuit when the heat of the molten metal is returned to the flow. Necessary characteristics for the gas such as a fairly low vaporization temperature and nonmiscibility with the metal, are outlined, and a space system using Li-Cs or Z-K as the heat carrier kept molten by a parabolic dish system is sketched. Equations governing the fluid mechanics, thermodynamics, and the electrical generation are defined. The construction of a prototype MHD generator using a tin-water flow operating at 250 C, a temperature suitable for coupling to solar heat sources, is outlined, noting expected efficiencies of 20-30 percent.

  17. Heat line analysis for MHD mixed convection flow of nanofluid within a driven cavity containing heat generating block

    NASA Astrophysics Data System (ADS)

    Parvin, Salma; Siddiqua, Ayesha

    2016-07-01

    Mixed convective flow and heat transfer characteristics of nanofluid inside a double lid driven cavity with a square heat generating block is analyzed numerically based on heat line approach. The water- alumina nanofluid is chosen as the operational fluid through the enclosure. The governing partial differential equations with proper boundary conditions are solved by Finite Element Method using Galerkin's weighted residual scheme. Calculations are performed for different solid volume fraction (χ) of nanoparticles 0 ≤ χ ≤ 0.15. Results are shown in terms of stream lines, isothermal lines, heat lines, average Nusselt number, average velocity and average temperature. An enhancement in heat transfer rate is observed with the increase of nanoparticles volume fraction.

  18. Slow shock and rotational discontinuity in MHD and Hall MHD models with anisotropic pressure

    NASA Astrophysics Data System (ADS)

    Hau, L.-N.; Wang, B.-J.

    2016-07-01

    Pressure anisotropy may modify the characteristics of magnetohydrodynamic (MHD) waves, in particular, the slow mode wave and the corresponding shocks and discontinuities. In this study the formation of slow shocks (SSs) in anisotropic plasmas is examined by solving the gyrotropic MHD and Hall MHD equations numerically for one-dimensional Riemann problem. The MHD shocks and discontinuities are generated by imposing a finite normal magnetic field on the Harris type current sheet with a guide magnetic By component. It is shown that anomalous SSs moving faster than the intermediate wave or with positive density-magnetic field correlation may be generated in gyrotropic MHD and Hall MHD models. Moreover, for some parameter values SSs may exhibit upstream wave trains with right-handed polarization in contrast with the earlier prediction that SSs shall possess downstream left-hand polarized wave trains based on the isotropic Hall MHD theory. For the cases of By ≠ 0, SSs with increased density and decreased magnetic field followed by noncoplanar intermediate mode or rotational discontinuity (RD)-like structures similar to the compound SS-RD structures observed in space plasma environments may possibly form in symmetric and asymmetric current layers. The Walén relation of these anomalous RDs without the correction of pressure anisotropy may significantly be violated.

  19. MHD control in burning plasmas MHD control in burning plasmas

    NASA Astrophysics Data System (ADS)

    Donné, Tony; Liang, Yunfeng

    2012-07-01

    Fusion physics focuses on the complex behaviour of hot plasmas confined by magnetic fields with the ultimate aim to develop a fusion power plant. In the future generation of tokamaks like ITER, the power generated by the fusion reactions substantially exceeds the external input power (Pfusion}/Pin >= 10). When this occurs one speaks of a burning plasma. Twenty per cent of the generated fusion power in a burning plasma is carried by the charged alpha particles, which transfer their energy to the ambient plasma in collisions, a process called thermalization. A new phenomenon in burning plasmas is that the alpha particles, which form a minority but carry a large fraction of the plasma kinetic energy, can collectively drive certain types of magneto-hydrodynamic (MHD) modes, while they can suppress other MHD modes. Both types of MHD modes can have desirable effects on the plasma, as well as be detrimental to the plasma. For example, the so-called sawtooth instability, on the one hand, is largely responsible for the transport of the thermalized alpha particles out of the core, but, on the other hand, may result in the loss of the energetic alphas before they have fully thermalized. A further undesirable effect of the sawtooth instability is that it may trigger other MHD modes such as neoclassical tearing modes (NTMs). These NTMs, in turn, are detrimental to the plasma confinement and in some cases may even lead to disruptive termination of the plasma. At the edge of the plasma, finally, so-called edge localized modes or ELMs occur, which result in extremely high transient heat and particle loads on the plasma-facing components of a reactor. In order to balance the desired and detrimental effects of these modes, active feedback control is required. An additional complication occurs in a burning plasma as the external heating power, which is nowadays generally used for plasma control, is small compared to the heating power of the alpha particles. The scientific challenge

  20. MHD heat and seed recovery technology project

    SciTech Connect

    Petrick, M.; Johnson, T. R.

    1980-08-01

    The MHD Heat and Seed Recovery Technology Project at Argonne National Laboratory is obtaining information for the design and operation of the steam plant downstream of the MHD channel-diffuser, and of the seed regeneration process. The project goal is to supply the engineering data required in the design of components for prototype and demonstration MHD facilities. The work is being done in close cooperation with the Heat Recovery-Seed Recovery facility, which will be a 20-MW pilot plant of the MHD steam bottoming system. The primary effort of the HSR Technology Project is directed toward experimental investigations of critical issues, such as 1) NO/sub x/ behavior in the radiant boiler and secondary combustor; 2) radiant boiler design to meet the multiple requirements of steam generation, NO/sub x/ decomposition, and seed slag separation; 3) effects of solid or liquid seed deposits on heat transfer and gas flow in the steam and air heaters; 4) formation, growth, and deposition of seed-slag particles, 5) character of the combustion gas effluents, and 6) the corrosion and erosion of ceramic and metallic materials of construction. These investigations are performed primarily in a 2-MW test facility, Argonne MHD Process Engineering Laboratory (AMPEL). Other project activities are related to studies of the thermochemistry of the seed-slag combustion gas system, identification of ceramic and metallic materials for service in the MHD-steam plant, and evaluation of seed regeneration processes. Progress is reported.

  1. High-bandwidth generation of duobinary and alternate-mark-inversion modulation formats using SOA-based signal processing.

    PubMed

    Dailey, James M; Power, Mark J; Webb, Roderick P; Manning, Robert J

    2011-12-19

    We report on the novel all-optical generation of duobinary (DB) and alternate-mark-inversion (AMI) modulation formats at 42.6 Gb/s from an input on-off keyed signal. The modulation converter consists of two semiconductor optical amplifier (SOA)-based Mach-Zehnder interferometer gates. A detailed SOA model numerically confirms the operational principles and experimental data shows successful AMI and DB conversion at 42.6 Gb/s. We also predict that the operational bandwidth can be extended beyond 40 Gb/s by utilizing a new pattern-effect suppression scheme, and demonstrate dramatic reductions in patterning up to 160 Gb/s. We show an increasing trade-off between pattern-effect reduction and mean output power with increasing bitrate.

  2. Magnetohydrodynamic electromagnetic pulse (MHD-EMP) interaction with power transmission and distribution systems

    SciTech Connect

    Tesche, F.M. , Dallas, TX ); Barnes, P.R. ); Meliopoulos, A.P.S. . Dept. of Electrical Engineering)

    1992-02-01

    This report discusses the effects of the late-time high-altitude electromagnetic pulse (HEMP) on electrical transmission and distribution (T D) systems. This environment, known as the magnetohydrodynamic electromagnetic pulse (MHD-EMP), is a very slowly varying electric field induced in the earth's surface, similar to the field induced by a geomagnetic storm. It can result in the flow of a quasi-dc current in grounded power lines and in the subsequent magnetic saturation of transformers. This saturation, in turn, causes 6-Hz harmonic distortion and an increase in the reactive power required by generation facilities. This report analyzes and discusses these phenomena. The MHD-EMP environment is briefly discussed, and a simplified form of the earth-induced electric field is developed for use in a parametric study of transmission line responses. Various field coupling models are described, and calculated results for the responses of both transmission- and distribution-class power lines are presented. These calculated responses are compared with measurements of transformer operation under dc excitation to infer the MHD-EMP response of these power system components. It is found that the MHD-EMP environment would have a marked effect on a power system by inducing up to several hundreds of amperes of quasi-dc current on power lines. These currents will cause transformers to saturate which could result in excessive harmonic generation, voltage swings, and voltage suppression. The design of critical facilities which are required to operate during and after MHD-EMP events will have to be modified in order to mitigate the effects of these abnormal power system conditions.

  3. Magnetohydrodynamic electromagnetic pulse (MHD-EMP) interaction with power transmission and distribution systems

    SciTech Connect

    Tesche, F.M.; Barnes, P.R.; Meliopoulos, A.P.S.

    1992-02-01

    This report discusses the effects of the late-time high-altitude electromagnetic pulse (HEMP) on electrical transmission and distribution (T&D) systems. This environment, known as the magnetohydrodynamic electromagnetic pulse (MHD-EMP), is a very slowly varying electric field induced in the earth`s surface, similar to the field induced by a geomagnetic storm. It can result in the flow of a quasi-dc current in grounded power lines and in the subsequent magnetic saturation of transformers. This saturation, in turn, causes 6-Hz harmonic distortion and an increase in the reactive power required by generation facilities. This report analyzes and discusses these phenomena. The MHD-EMP environment is briefly discussed, and a simplified form of the earth-induced electric field is developed for use in a parametric study of transmission line responses. Various field coupling models are described, and calculated results for the responses of both transmission- and distribution-class power lines are presented. These calculated responses are compared with measurements of transformer operation under dc excitation to infer the MHD-EMP response of these power system components. It is found that the MHD-EMP environment would have a marked effect on a power system by inducing up to several hundreds of amperes of quasi-dc current on power lines. These currents will cause transformers to saturate which could result in excessive harmonic generation, voltage swings, and voltage suppression. The design of critical facilities which are required to operate during and after MHD-EMP events will have to be modified in order to mitigate the effects of these abnormal power system conditions.

  4. MHD energy fluxes for late type dwarfs

    NASA Technical Reports Server (NTRS)

    Rosner, R.; Musielak, Z. E.

    1987-01-01

    The efficiency of MHD wave generation by turbulent motions in stratified stellar atmospheres with embedded uniform magnetic fields is calculated. In contradiction with previous results, it is shown that there is no significant increase in the efficiency of wave generation because of the presence of magnetic fields, at least within the theory's limits of applicability. It is shown that MHD energy fluxes for late-type stars are less than those obtained for acoustic waves in a magnetic-field-free atmosphere, and do not vary enough for a given spectral type in order to explain observed UV and X-ray fluxes. Thus, the results show that MHD energy fluxes obtained if stellar surface magnetic fields are uniform cannot explain the observed stellar coronal emissions.

  5. Antibody-enhanced dengue disease generates a marked CNS inflammatory response in the black-tufted marmoset Callithrix penicillata.

    PubMed

    Vasconcelos, Barbara Cristina Baldez; Vieira, Juliana Almeida; Silva, Geane Oliveira; Fernandes, Taiany Nogueira; Rocha, Luciano Chaves; Viana, André Pereira; Serique, Cássio Diego Sá; Filho, Carlos Santos; Bringel, Raissa Aires Ribeiro; Teixeira, Francisco Fernando Dacier Lobato; Ferreira, Milene Silveira; Casseb, Samir Mansour Moraes; Carvalho, Valéria Lima; de Melo, Karla Fabiane Lopes; de Castro, Paulo Henrique Gomes; Araújo, Sanderson Corrêa; Diniz, José Antonio Picanço; Demachki, Samia; Anaissi, Ana Karyssa Mendes; Sosthenes, Marcia Consentino Kronka; Vasconcelos, Pedro Fernando da Costa; Anthony, Daniel Clive; Diniz, Cristovam Wanderley Picanço; Diniz, Daniel Guerreiro

    2016-02-01

    Severe dengue disease is often associated with long-term neurological impairments, but it is unclear what mechanisms are associated with neurological sequelae. Previously, we demonstrated antibody-enhanced dengue disease (ADE) dengue in an immunocompetent mouse model with a dengue virus 2 (DENV2) antibody injection followed by DENV3 virus infection. Here we migrated this ADE model to Callithrix penicillata. To mimic human multiple infections of endemic zones where abundant vectors and multiple serotypes co-exist, three animals received weekly subcutaneous injections of DENV3 (genotype III)-infected supernatant of C6/36 cell cultures, followed 24 h later by anti-DENV2 antibody for 12 weeks. There were six control animals, two of which received weekly anti-DENV2 antibodies, and four further animals received no injections. After multiple infections, brain, liver, and spleen samples were collected and tissue was immunolabeled for DENV3 antigens, ionized calcium binding adapter molecule 1, Ki-67, TNFα. There were marked morphological changes in the microglial population of ADE monkeys characterized by more highly ramified microglial processes, higher numbers of trees and larger surface areas. These changes were associated with intense TNFα-positive immunolabeling. It is unclear why ADE should generate such microglial activation given that IgG does not cross the blood-brain barrier, but this study reveals that in ADE dengue therapy targeting the CNS host response is likely to be important.

  6. [Incidence of factor VII and C3 in vascular anastomosis].

    PubMed

    Skóra, Jan; Janczak, Dariusz; Korta, Krzysztof; Pupka, Artur; Ruciński, Artur; Szyber, Piotr; Pawłowski, Stanisław; Milnerowicz, Artur; Stepiński, Piotr

    2004-06-01

    In order to study pathogenesis of vascular prosthesis healing process the following experiment was designed. 16 dogs underwent implantation of unilateral straight aorto-femoral teflon (PTFE, polytetrafluoroethylene) by-pass. After 6 months all dogs were killed, dissected and vascular prostheses with margin of adjacent aorta and femoral artery were collected for further study. Areas of proximal and distal anastomosis were examined immunohistochemically. Presence of coagulation factor VII, and C3 complement factor were studied. The obtained results were analyzed statistically by means of t-Student test. Factor VII as well C3 were found in areas of both proximal and distal anastomosis. Concentration of all two substances in proximal and distal anastomosis was compared. No statistically valid differences in factor VII concentration in proximal and distal anastomosis were found, whereas amounts of C3 factor as well as degree of extracellular matrix infiltration were markedly higher in distal anastomosis.

  7. Intelsat VII planning and evolution

    NASA Astrophysics Data System (ADS)

    Nadkarni, P.; Neyret, P.; Allnutt, J.; Chidambaram, T.

    This paper describes the evolution of the Intelsat VII concept from among a number of spacecraft concepts considered in the planning process. The considerations of greatest importance in this evolution are examined, including the compatibility with small earth stations, available digital services and circuit multiplication techniques, schedule considerations, launch vehicle considerations, and operational flexibility. The roles of demand analysis and of architecture selection in the development of the Intelsat VII concept are addressed.

  8. MHD simulations: Corotating Interaction Regions

    NASA Astrophysics Data System (ADS)

    Wiengarten, T.; Kleimann, J.; Fichtner, H.; Kühl, P.; Heber, B.; Kissmann, R.

    2013-12-01

    Corotating Interaction Regions (CIRs) form in the solar wind when parcels of fast-speed wind interact with slow-speed wind due to the rotation of the Sun. The resulting buildup of pressure generates disturbances that, with increasing time (or distance from the Sun), may develop into a so-called forward-reverse shock-pair. During solar-quiet times CIRs can be the dominant force shaping large-scale structures in the heliosphere. Studying CIRs is therefore important because the associated shocks are capable of e.g. accelerating energetic particles or deflecting cosmic rays. The global structure of CIRs can be modeled with an MHD approach that gives the plasma quantities needed to model the transport of particles in the heliosphere (with e.g. stochastic differential equations (SDEs)). Our MHD code CRONOS employs a semi-discrete finite volume scheme with adaptive time-stepping Runge-Kutta integration. The solenoidality of the magnetic field is ensured via constrained transport and the code supports Cartesian, Cylindrical and Spherical coordinates (including coordinate singularities) with the option for non-equidistant grids. The code runs in parallel (MPI) and supports the HDF5 output data format. Here, we show results from 3D-MHD simulations with our code CRONOS for a) analytic boundary conditions where results can be compared to those obtained with a different code and b) boundary conditions derived with the Wang-Sheeley-Arge model from observational data (WSO), which are compared to spacecraft observations. Comparison with Pizzo (1982) for analytic boundary conditions Comparison with STEREO A for Carrington Rotation 2060

  9. BUGJEFF311.BOLIB (JEFF-3.1.1) and BUGENDF70.BOLIB (ENDF/B-VII.0) - Generation Methodology and Preliminary Testing of two ENEA-Bologna Group Cross Section Libraries for LWR Shielding and Pressure Vessel Dosimetry

    NASA Astrophysics Data System (ADS)

    Pescarini, Massimo; Sinitsa, Valentin; Orsi, Roberto; Frisoni, Manuela

    2016-02-01

    Two broad-group coupled neutron/photon working cross section libraries in FIDO-ANISN format, dedicated to LWR shielding and pressure vessel dosimetry applications, were generated following the methodology recommended by the US ANSI/ANS-6.1.2-1999 (R2009) standard. These libraries, named BUGJEFF311.BOLIB and BUGENDF70.BOLIB, are respectively based on JEFF-3.1.1 and ENDF/B-VII.0 nuclear data and adopt the same broad-group energy structure (47 n + 20 γ) of the ORNL BUGLE-96 similar library. They were respectively obtained from the ENEA-Bologna VITJEFF311.BOLIB and VITENDF70.BOLIB libraries in AMPX format for nuclear fission applications through problem-dependent cross section collapsing with the ENEA-Bologna 2007 revision of the ORNL SCAMPI nuclear data processing system. Both previous libraries are based on the Bondarenko self-shielding factor method and have the same AMPX format and fine-group energy structure (199 n + 42 γ) as the ORNL VITAMIN-B6 similar library from which BUGLE-96 was obtained at ORNL. A synthesis of a preliminary validation of the cited BUGLE-type libraries, performed through 3D fixed source transport calculations with the ORNL TORT-3.2 SN code, is included. The calculations were dedicated to the PCA-Replica 12/13 and VENUS-3 engineering neutron shielding benchmark experiments, specifically conceived to test the accuracy of nuclear data and transport codes in LWR shielding and radiation damage analyses.

  10. MHD Simulations: Corotating Interaction Regions

    NASA Astrophysics Data System (ADS)

    Wiengarten, T.; Kleimann, J.; Fichtner, H.; Kissmann, R.

    2014-09-01

    Corotating Interaction Regions (CIRs) form in the solar wind when parcels of fast-speed wind interact with slow-speed wind due to the rotation of the Sun. The resulting buildup of pressure generates disturbances that, with increasing time (or distance from the Sun), may develop into a so-called forward-reverse shock pair. During solar-quiet times CIRs can be the dominant force shaping large-scale structures in the heliosphere. Studying CIRs is therefore important because the associated shocks are capable of e.g. accelerating energetic particles or deflecting cosmic rays. The global structure of CIRs can be modeled with an MHD approach that gives the plasma quantities needed to model the transport of particles in the heliosphere with e.g. stochastic differential equations. Here, we show results from 3D-MHD simulations with our code CRONOS for a) analytic boundary conditions where results can be compared to those obtained with a different code and b) boundary conditions derived with the Wang-Sheeley-Arge model from observational data (WSO), which are compared to spacecraft observations.

  11. MHD performance demonstration experiment, FY 1974 to FY 1984

    NASA Astrophysics Data System (ADS)

    Whitehead, G. L.; Christensen, L. S.; Felderman, R. J.

    1984-06-01

    A national program for the development of commercial, open-cycle, magnetohydrodynamic (MHD) power generation is described. The emphasis of that national program was, and is, on establishing the engineering feasibilty of using coal to fuel the MHD power system. In order to establish feasibility it was necessary to experimentally demonstrate that an MHD generator system simulating a commercial-sized device can convert 16 to 18% of the available thermal energy into electric power at an isentropic efficiency of 60 to 70%. A presidential decree encouraged any government agency which might possess an organic MHD capability to assist ERDA in formulating and executing the national program. Since the largest MHD facility in the United States was located at the Arnold Engineering Development Center (AEDC), it was selected to be the national program element to demonstrate performance. As a result, the AEDC has been under contract since December 1973 (first to ERDA, later to its successor, the department of Energy, DOE) to modify existing equipment and to design, fabricate, and install new hardware to perform the MHD Performance Demonstration Experiment. The MHD facility is described and all results achieved to date are summarized.

  12. Fuel conservation and pollution control by MHD

    NASA Astrophysics Data System (ADS)

    Messerle, H. K.; Campbell, B.

    1980-06-01

    MHD generators, which directly convert thermal energy in a fluid into electricity, promise a more effective use of fuel for bulk power production than conventional steam plants, bettering efficiency by over 50% and reducing the generating cost by 20%. Using a Rankine steam cycle, overall power plant efficiency can increase from 33% to 50%, while fuel requirements can be reduced by one third and thermal pollution by one half. Since overall fuel consumption would drop, atmospheric pollution would be decreased, and coal consumption could be diverted to areas where oil is presently being used. The MHD generator structure and operation are discussed, and its general system requirements are explained. A table of energy use and an efficiency graph are provided for comparison purposes. Work is currently being done on a 2 MW open cycle MHD generator at the University of Sydney, Australia, and computer studies are in progress to evaluate the Faraday generator performance for the experimental 2 MW facility and larger power generators with segmented sets of electrodes.

  13. System studies of coal fired-closed cycle MHD for central station power plants

    NASA Technical Reports Server (NTRS)

    Zauderer, B.

    1976-01-01

    This paper presents a discussion of the closed-cycle MHD results obtained in a recent study of various advanced energy-conversion power systems. The direct coal-fired MHD topping-steam bottoming cycle was established as the current choice for central station power generation. Emphasis is placed on the background assumptions and the conclusions that can be drawn from the closed-cycle MHD analysis. It is concluded that closed-cycle MHD has efficiencies comparable to that of open-cycle MHD. Its cost will possibly be slightly higher than that of the open-cycle MHD system. Also, with reasonable fuel escalation assumptions, both systems can produce lower-cost electricity than conventional steam power plants. Suggestions for further work in closed-cycle MHD components and systems are made.

  14. Differential regulation and impact of fucosyltransferase VII and core 2 β1,6-N-acetyl-glycosaminyltransferase for generation of E-selectin and P-selectin ligands in murine CD4+ T cells.

    PubMed

    Schroeter, Micha F; Ratsch, Boris A; Lehmann, Jeanette; Baumgrass, Ria; Hamann, Alf; Syrbe, Uta

    2012-12-01

    Ligands for E-selectin and P-selectin (E-lig and P-lig) are induced on CD4+ T cells upon differentiation into effector T cells. Glycosyltransferases, especially α 1,3-fucosyltransferase VII (FucT-VII) and core 2 β1,6-N-acetyl-glycosaminyltransferase I (C2GlcNAcT-I), are critical for their synthesis. We here analysed the signals that control the expression of E-lig, P-lig and mRNA coding for FucT-VII and C2GlcNAcT-I. In line with previous reports, we found that P-lig expression correlates with the regulation of C2GlcNAcT-I, whereas E-lig expression can occur at low levels of C2GlcNAcT-I mRNA but requires high FucT-VII mRNA expression. Interestingly, the two enzymes are regulated by different signals. Activation-induced C2GlcNAcT-I up-regulation under permissive (T helper type 1) conditions was strongly reduced by cyclosporin A (CsA), suggesting the involvement of T-cell receptor-dependent, calcineurin/NFAT-dependent signals in combination with interleukin-12 (IL-12) -mediated signals in the regulation of C2GlcNAcT-I. In contrast, expression of FucT-VII mRNA was not significantly inhibited by CsA. Interleukin-4 inhibited the expression of FucT-VII but IL-2 and IL-7 were found to support induction of FucT-VII and E-lig. E-selectin, P-selectin and their ligands initially appeared to have rather overlapping functions. These findings however, unravel striking differences in the regulation of E-lig and P-lig expression, dictated by the dominance of FucT-VII and C2GlcNAcT-I, respectively, and their dependency on signals from either promiscuous or homeostatic cytokines (FucT-VII) or a strong T-cell receptor signal in combination with inflammatory cytokines in case of C2GlcNAcT-I.

  15. Proceedings of the workshop on nonlinear MHD and extended MHD

    SciTech Connect

    1998-12-01

    Nonlinear MHD simulations have proven their value in interpreting experimental results over the years. As magnetic fusion experiments reach higher performance regimes, more sophisticated experimental diagnostics coupled with ever expanding computer capabilities have increased both the need for and the feasibility of nonlinear global simulations using models more realistic than regular ideal and resistive MHD. Such extended-MHD nonlinear simulations have already begun to produce useful results. These studies are expected to lead to ever more comprehensive simulation models in the future and to play a vital role in fully understanding fusion plasmas. Topics include the following: (1) current state of nonlinear MHD and extended-MHD simulations; (2) comparisons to experimental data; (3) discussions between experimentalists and theorists; (4) /equations for extended-MHD models, kinetic-based closures; and (5) paths toward more comprehensive simulation models, etc. Selected papers have been indexed separately for inclusion in the Energy Science and Technology Database.

  16. Generation and evaluation of a recombinant genotype VII Newcastle disease virus expressing VP3 protein of Goose parvovirus as a bivalent vaccine in goslings.

    PubMed

    Wang, Jianzhong; Cong, Yanlong; Yin, Renfu; Feng, Na; Yang, Songtao; Xia, Xianzhu; Xiao, Yueqiang; Wang, Wenxiu; Liu, Xiufan; Hu, Shunlin; Ding, Chan; Yu, Shengqing; Wang, Chunfeng; Ding, Zhuang

    2015-05-04

    Newcastle disease virus (NDV) and Goose parvovirus (GPV) are considered to be two of the most important and widespread viruses infecting geese. In this study, we generated a recombinant rmNA-VP3, expressing GPV VP3 using a modified goose-origin NDV NA-1 by changing the multi-basic cleavage site motif RRQKR↓F of the F protein to the dibasic motif GRQGR↓L as that of the avirulent strain LaSota as a vaccine vector. Expression of the VP3 protein in rmNA-VP3 infected cells was detected by immunofluorescence and Western blot assay. The genetic stability was examined by serially passaging 10 times in 10-day-old embryonated SPF chicken eggs. Goslings were inoculated with rmNA-VP3 showed no apparent signs of disease and developed a strong GPV and NDV neutralizing antibodies response. This is the first study demonstrating that recombinant NDV has the potential to serve as bivalent live vaccine against Goose parvovirus and Newcastle disease virus infection in birds.

  17. Generation of higher-order atomic dipole squeezing in a high-Q micromaser cavity. (VII). Entangled two-mode coherent states

    NASA Astrophysics Data System (ADS)

    Xie, Rui-Hua; Rao, Qin

    2002-12-01

    In our preceding paper V, we investigated the generation of higher-order atomic dipole squeezing (HOADS) in a nondegenerate two-photon Jaynes-Cummings model (NTPJCM) in the presence of Stark shift. In this paper, we continue to study HOADS in this model but focus on the specific cases that the radiation field is initially prepared in a two-mode entangled state (e.g., two-mode squeezed vacuum state, two-mode Perelomov and Barut-Girardello coherent states). It is found that increasing the fixed difference in the photon numbers of the two-mode entangled states of the radiation field could decrease the squeeze duration and shorten the squeeze period, and the detuning may lead to much effective HOADS by properly adjusting certain value. In general, the Stark shift has a destructive effect on HOADS, but the combined effect of the detuning and Stark shift could increase the squeeze duration and lead to regular and periodical HOADS pattern. The influence of atomic coherence on HOADS is also examined in detail.

  18. HVEPS Scramjet-Driven MHD Power Demonstration Test Results (Preprint)

    DTIC Science & Technology

    2007-06-01

    direct connect mode with a vacuum air ejector exhaust system that holds back pressure to about 4.0 psia in the downsteam exhaust quench tank ...analytical verification. The static pressure distribution data in comparison to CFD results and past tests, provides a high degree of confidence that... pressure , high temperature combustor to produce a high velocity plasma, flow that drives the MHD generator. The self-contained combustion-driven MHD

  19. Conceptual design of the MHD Engineering Test Facility

    NASA Astrophysics Data System (ADS)

    Bents, D. J.; Bercaw, R. W.; Burkhart, J. A.; Mroz, T. S.; Rigo, H. S.; Pearson, C. V.; Warinner, D. K.; Hatch, A. M.; Borden, M.; Giza, D. A.

    The reference conceptual design of the MHD engineering test facility, a prototype 200 MWe coal-fired electric generating plant designed to demonstrate the commerical feasibility of open cycle MHD is summarized. Main elements of the design are identified and explained, and the rationale behind them is reviewed. Major systems and plant facilities are listed and discussed. Construction cost and schedule estimates are included and the engineering issues that should be reexamined are identified.

  20. An experimental studies with disk MHD channels on argon plazma

    SciTech Connect

    Koneev, S.M.A.; Kovalev, L.K.; Larionoff, A.E.; Poltavets, V.N.

    1994-12-31

    The most interesting works carried out over the past few years in the field of MHD generating electric power are the ones studying disk MHD channels. The results published give a hope to overcome one of the MHD generator essential disadvantages - relatively low effectiveness of converting heat power into electric one. In some works performed by different authors and at different plants the coefficients of energy conversion achieving 20% have been obtained and there is a hint of the future possible increase of up to 40%. In the majority of experimental studies non-equilibrium ionized inertial gases (Ar, He) with alkali metal (Cs, K) were used as a working medium, the operating temperature being 1800-2000 K. The present paper is dedicated to an experimental test rig-with-a-disk-MHD-channel development for operating on thermally ionized Ar with the temperature of up to 9000 K and pressure 10 up to 10 Pa. For heating a working medium an electric arc in a special plazmotron is used. As the experiments on linear MHD channels have shown, along the whole working area the plasma is non-equilibrium with a substantial break off of an electron temperature providing conductivity of more then 100 Sm/m. The aim of creation this test rig is in simulating the processes of the working medium flow and electric energy generation in disk MHD channels. An important research element is calculation techniques debugging and acquiring experience of development and carrying out disk MHD generator studies for the following experimental full-scale MHD plants with a disk channel to be created.

  1. Conceptual design of the MHD Engineering Test Facility

    NASA Technical Reports Server (NTRS)

    Bents, D. J.; Bercaw, R. W.; Burkhart, J. A.; Mroz, T. S.; Rigo, H. S.; Pearson, C. V.; Warinner, D. K.; Hatch, A. M.; Borden, M.; Giza, D. A.

    1981-01-01

    The reference conceptual design of the MHD engineering test facility, a prototype 200 MWe coal-fired electric generating plant designed to demonstrate the commerical feasibility of open cycle MHD is summarized. Main elements of the design are identified and explained, and the rationale behind them is reviewed. Major systems and plant facilities are listed and discussed. Construction cost and schedule estimates are included and the engineering issues that should be reexamined are identified.

  2. MHD Flow Control

    DTIC Science & Technology

    2006-09-01

    Plasmatron // The 15th International Conference on 16 N I MHD Energy Conversion and the 6th International Workshop on MagnetoPlasma Aerodynamics, IVTAN...series. 1 2. FACILITY The principal scheme of High Frequency Plasmatron is given in Fig.88, and basic specifications in the Table 1. The high-frequency...CHAMBER OF HF- PLASMATRON Statement of the problem Detailed diagnostics of plasma jet flow is required for any type of studies in HF- plasmatron . Gas flow in

  3. Nuclear MHD Converter

    DTIC Science & Technology

    2007-11-02

    model the Power Conversion Unit (gas reactor + nozzle and MHD channel), and the cross sections derived from Task 1.. The configuration extends ...8 1.1 Project Objectives 8 1.2 Report Organization 9 Tables and Figures 10 2 PROJECT DESCRIPTION 11 3 REFLECTOR MODELING 13 3.1 Symbols...outlet. This conclusion remains true even if the effect of dissociation and attachment are included in the numerical model . Furthermore, a

  4. MHD channel development, part 2

    NASA Astrophysics Data System (ADS)

    1989-12-01

    This is the final report of work performed by Avco Research Laboratory, Inc. for the U.S. Department of Energy, Pittsburgh Energy Technology Center. The overall objectives of this program were: to contribute, by appropriate systematic experimental and analytical investigations, to the engineering data base necessary for the design and construction of MHD generators at the 50 MW(sub th) and ultimately at commercial sizes; and to design and fabricate specific hardware items to be tested at a site to be specified by DOE. The program consisted of a series of related tasks, which are described in subsequent sections of this report. Section 2.0 summarizes the important results of the entire program.

  5. Analytical investigation of critical MHD phenomena

    NASA Technical Reports Server (NTRS)

    1981-01-01

    Development and analysis of schemes for suppression of the startup overvoltage transient in the AEDC High Performance Demonstration Experiment (HPDE), analysis of performance enhancement due to electrode voltage drop reduction by use of pyrolytic graphites in the HPDE, prediction of optimal loading schemes for the HPDE, prediction of PHDE performance with a diagonal electrical connection, and predictions of the likelihood and effects of axial current leakage between adjacent electrodes in the HPDE are reviewed. Simulations of tests at the AEDC/HPDE with STD Research Corporation multidimensional and time dependent computer codes provided additional validation for the computer codes and shed light on physical mechanisms which govern performance and durability of MHD power generators. The magnetoaerothermal effect was predicted by STD Research Corporation to have a significant effect on the HPDE/MHD generator performance at high interaction.

  6. Stretch Marks

    MedlinePlus

    ... like during puberty), that person may get fine lines on the body called stretch marks. Stretch marks happen when the skin is pulled by rapid growth or stretching. Although the skin is usually fairly elastic, when it's overstretched, the normal production of collagen (the major protein that makes up ...

  7. The relationship between the monitored performance of tutors and students at PBL tutorials and the marked hypotheses generated by students in a hybrid curriculum

    PubMed Central

    Addae, Jonas I.; Sahu, Pradeep; Sa, Bidyadhar

    2017-01-01

    ABSTRACT Introduction: There have been a number of published studies examining the link between the effectiveness of the problem-based learning (PBL) process and students’ performance in examinations. In a hybrid PBL/lectures curriculum, the results of such studies are of limited use because of the difficulty in dissociating the knowledge gained at lectures from that gained through PBL-related activities. Hence, the objectives of this study were: (1) to develop an instrument to measure the performance of tutors and students at PBL tutorials, and (2) to explore the contribution of such performances to the marks attained by students from the hypotheses generated at PBL tutorials. Methods: A monitoring instrument for assessing the performances of non-expert tutors and students at tutorials was developed and validated using principal component analysis and reliability analysis. Also, a rubric was formulated to enable a content expert to assign marks to the quality of hypotheses generated. Results: The monitoring instrument was found to be valid and reliable. There was a significant correlation between the performance of tutors at tutorials and hypotheses marks. In contrast, there was no significant correlation between the performance of students and hypotheses marks. Discussion: The monitoring instrument is a useful tool for improving the PBL process, especially where the medical programme depends on non-expert PBL tutors. In addition to ensuring good PBL processes, it is important that students achieve the desired output at PBL tutorials by producing hypotheses that help them understand the basic sciences underlying the clinical cases. The latter is achieved by the use of an open-ended rubric by a subject expert to assign marks to the hypotheses, a method that also provides additional motivation to students to develop relevant and detailed hypotheses. PMID:28178915

  8. Magnetohydrodynamics (MHD) Engineering Test Facility (ETF) 200 MWe power plant Conceptual Design Engineering Report (CDER)

    NASA Technical Reports Server (NTRS)

    1981-01-01

    The reference conceptual design of the magnetohydrodynamic (MHD) Engineering Test Facility (ETF), a prototype 200 MWe coal-fired electric generating plant designed to demonstrate the commercial feasibility of open cycle MHD, is summarized. Main elements of the design, systems, and plant facilities are illustrated. System design descriptions are included for closed cycle cooling water, industrial gas systems, fuel oil, boiler flue gas, coal management, seed management, slag management, plant industrial waste, fire service water, oxidant supply, MHD power ventilating

  9. Output from MHD Models

    NASA Astrophysics Data System (ADS)

    Vlahakis, Nektarios

    2010-03-01

    Outflows emanating from the environment of stellar or galactic objects are a widespread phenomenon in astrophysics. Their morphology ranges from nearly spherically symmetric winds to highly collimated jets. In some cases, e.g., in jets associated with young stellar objects, the bulk outflow speeds are nonrelativistic, while in others, e.g., in jets associated with active galactic nuclei or gamma-ray bursts, it can even be highly relativistic. The main driving mechanism of collimated outflows is likely related to magnetic fields. These fields are able to tap the rotational energy of the compact object or disk, accelerate, and collimate matter ejecta. To zeroth order these outflows can be described by the highly intractable theory of magnetohydrodynamics (MHD). Even in systems where the assumptions of zero resistivity (ideal MHD), steady state, axisymmetry, one fluid description, and polytropic equation of state are applicable, the problem remains difficult. In this case the problem reduces to only two equations, corresponding to the two components of the momentum equation along the flow and in the direction perpendicular to the magnetic field (transfield direction). The latter equation is the most difficult to solve, but also the most important. It answers the question on the degree of the collimation, but also crucially affects the solution of the first, the acceleration efficiency and the bulk velocity of the flow. The first and second parts of this chapter refer to nonrelativistic and relativistic flows, respectively. These Parts can be read independently. In each one, the governing equations are presented and discussed, focusing on the case of flows that are magnetically dominated near the central source. The general characteristics of the solutions in relation to the acceleration and collimation mechanisms are analyzed. As specific examples of exact solutions of the full system of the MHD equations that satisfy all the analyzed general characteristics, self

  10. MHD Program Plan, FY 1992

    NASA Astrophysics Data System (ADS)

    1991-10-01

    The current MHD program being implemented is a result of a consensus established in public meetings held by the Department of Energy in 1984. Essential elements of the current program include the following: (1) develop technical and environmental data for the integrated MHD topping cycle system through POC testing (1,000 hours); (2) develop technical and environmental data for the integrated MHD bottoming cycle sub system through POC testing (4,000 hours); (3) design, construct, and operate a seed regeneration POC facility (SRPF) capable of processing spent seed materials from the MHD bottoming cycle; (4) prepare conceptual designs for a site specific MHD retrofit plant; and (5) continue system studies and supporting research necessary for system testing. The current MHD program continues to be directed toward coal fired power plant applications, both stand-alone and retrofit. Development of a plant should enhance the attractiveness of MHD for applications other than electrical power. MHD may find application in electrical energy intensive industries and in the defense sector.

  11. Marking Time

    ERIC Educational Resources Information Center

    Foster, Colin

    2011-01-01

    Teachers say that they would gladly teach a day in the classroom if at the end of the day they could leave and have no marking. There is a common staffroom perception that mathematics teachers have it easy when it comes to marking. In arts subjects, setting an essay can be a fairly straightforward matter--a one-line question may suffice--but…

  12. In vivo studies of the role of factor VII in hemostasis.

    PubMed

    Giles, A R; Tinlin, S; Brosseau, L; Hoogendoorn, H

    1985-05-01

    The effect of both congenital and acquired factor VII deficiency on the cuticle bleeding time (CBT) was evaluated in dogs. The CBT has been previously documented to be a sensitive indicator of factor VIII:C deficiency in hemophilic dogs. Serial CBT determinations were made on normal dogs treated with high-dose warfarin. At 48 hours post-treatment, the CBT was normal, although the factor VII level was less than 1%, whereas the levels of factors II, IX, and X were 44%, 25%, and 17%, respectively. At 120 hours the CBT became abnormal when all vitamin K-dependent clotting factors had dropped to less than 18%. Administration of a plasma concentrate of factors II, IX, and X corrected the CBT, despite the factor VII level remaining at less than 1%. Similar studies in a congenitally factor VII-deficient dog (factor VII less than 2%) confirmed that this deficiency state was not associated with an abnormality of the CBT. Administration of heparin to both normal and factor VII-deficient animals was associated with prolongation of the CBT, but the heparin dose required in the normal animals was substantially higher than in the factor VII-deficient animals. These data do not suggest that factor VII/VIIa has an exclusive role in generating factor Xa, either directly or indirectly, by way of factor IXa generation, in vivo. However, the increase in heparin sensitivity of the factor VII-deficient animals does suggest that factor VII/VIIa may, in some circumstances, present a significant alternative pathway of factor X activation, although the activation pathway involved cannot be determined from the studies performed.

  13. Annular MHD Physics for Turbojet Energy Bypass

    NASA Technical Reports Server (NTRS)

    Schneider, Steven J.

    2011-01-01

    The use of annular Hall type MHD generator/accelerator ducts for turbojet energy bypass is evaluated assuming weakly ionized flows obtained from pulsed nanosecond discharges. The equations for a 1-D, axisymmetric MHD generator/accelerator are derived and numerically integrated to determine the generator/accelerator performance characteristics. The concept offers a shockless means of interacting with high speed inlet flows and potentially offers variable inlet geometry performance without the complexity of moving parts simply by varying the generator loading parameter. The cycle analysis conducted iteratively with a spike inlet and turbojet flying at M = 7 at 30 km altitude is estimated to have a positive thrust per unit mass flow of 185 N-s/kg. The turbojet allowable combustor temperature is set at an aggressive 2200 deg K. The annular MHD Hall generator/accelerator is L = 3 m in length with a B(sub r) = 5 Tesla magnetic field and a conductivity of sigma = 5 mho/m for the generator and sigma= 1.0 mho/m for the accelerator. The calculated isentropic efficiency for the generator is eta(sub sg) = 84 percent at an enthalpy extraction ratio, eta(sub Ng) = 0.63. The calculated isentropic efficiency for the accelerator is eta(sub sa) = 81 percent at an enthalpy addition ratio, eta(sub Na) = 0.62. An assessment of the ionization fraction necessary to achieve a conductivity of sigma = 1.0 mho/m is n(sub e)/n = 1.90 X 10(exp -6), and for sigma = 5.0 mho/m is n(sub e)/n = 9.52 X 10(exp -6).

  14. Cometary MHD and chemistry

    NASA Technical Reports Server (NTRS)

    Wegmann, R.; Schmidt, H. U.; Huebner, W. F.; Boice, D. C.

    1987-01-01

    An MHD and chemical comet-coma model was developed, applying the computer program of Huebner (1985) for the detailed chemical evolution of a spherically expanding coma and the program of Schmidt and Wegman (1982) and Wegman (1987) for the MHD flow of plasma and magnetic field in a comet to the Giotto-mission data on the ion abundances measured by the HIS ion mass spectrometer. The physics and chemistry of the coma are modeled in great detail, including photoprocesses, gas-phase chemical kinetics, energy balance with a separate electron temperature, multifluid hydrodynamics with a transition to free molecular flow, fast-streaming atomic and molecular hydrogen, counter and cross streaming of the ionized species relative to the neutral species in the coma-solar wind interaction region with momentum exchange by elastic collisions, mass-loading through ion pick-up, and Lorentz forces of the advected magnetic field. The results, both inside and outside of the contact surface, are discussed and compared with the relevant HIS ion mass spectra.

  15. Results from a large-scale MHD propulsion experiment

    NASA Astrophysics Data System (ADS)

    Petrick, M.; Libera, J.; Bouillard, J. X.; Pierson, E. S.; Hill, D.

    Magnetohydrodynamic (MHD) thrusters have long been recognized as potentially attractive candidates for ship propulsion because such systems eliminate the conventional rotating drive components. The MHD thruster is essentially an electromagnetic (EM) pump operating in seawater. An electrical current is passed directly through the seawater and interacts with an applied magnetic field; the interaction of the magnetic field and the electrode current in the seawater results in a Lorentz force acting on the water, and the reaction to this force propels the vessel forward. The concept of EM propulsion has been examined periodically during the past 35 years as an alternative method of propulsion for surface ships and submersibles. The conclusions reached in early studies were that MHD thrusters restricted to fields of 2 T (the state-of-the-art at that time) were impractical and very inefficient. With the evolution of superconducting magnet technology, later studies investigated the performance of MHD thrusters with much higher magnetic field strengths and concluded that at higher fields (greater than 6-T) practical MHD propulsion systems appear possible. The feasibility of attaining the requisite higher magnetic fields has increased markedly because of rapid advances in building high-field superconducting magnets and the recent evolution of high-temperature superconductors.

  16. System study of an MHD/gas turbine combined-cycle baseload power plant

    NASA Astrophysics Data System (ADS)

    Annen, K. D.

    1981-08-01

    The magnetohydrodynamics (MHD) gas turbine systems were modeled with sufficient detail, using realistic component specifications and costs, so that that the thermal and economic performance of the systems could be accurately determined. Three cases of MHD gas turbine systems were studied, with Case I being similar to a MHD steam system so that a direct comparison of the performances could be made, with Case II being representative of a second generation MHD system, and with Case III considering oxygen enrichment for early commercial applications. The results show that the MHD gas turbine system has very good thermal and economic performances while requiring either little or no cooling water. Compared to the MHD steam system which has a cooling tower heat load of 720 MN, the Base Case I MHD/gas turbine system has a heat rate which is 13% higher and a cost of electricity which is only 7% higher while requiring no cooling water. Case II results show that an improved performance can be expected from second generation MHD gas turbine systems. Case III results show that an oxygen enriched MHD gas turbine system may be attractive for early commercial applications in dry regions of the country.

  17. NASA Lewis Research Center combustion MHD experiment

    NASA Astrophysics Data System (ADS)

    Smith, J. M.

    The MHD power generation experiments were conducted in a high field strength cryomagnet which was adapted from an existing facility. In its original construction, it consisted of 12 high purity aluminum coils pool cooled in a bath of liquid neon. In this configuration, a peak field of 15 tesla was produced. For the present experiments, the center four coils were removed and a 23 cm diameter transverse warm bore tube was inserted to allow the placement of the MHD experiment between the remaining eight coils. In this configuration, a peak field of 6 tesla should be obtainable. The time duration of the experiment is limited by the neon supply which allows on the order of 1 minute of total operating time followed by an 18-hour reliquefaction period. As a result, the experiments are run in a pulsed mode. The run duration for the data presented here was 5 sec. The magnetic field profile along the MHD duct is shown. Since the working fluid is in essence superheated steam, it is easily water quenched at the exit of the diffuser and the components are designed vacuum tight so that the exhaust pipe and demister an be pumped down to simulate the vacuum of outer space.

  18. MHD turbulent mixing layers

    SciTech Connect

    Esquivel, A.; Lazarian, A.; Benjamin, R.A.; Cho, J.; Leitner, S.N.

    2005-09-28

    Turbulent mixing layers have been proposed to explain observations of line ratios of highly ionized elements in the interstellar medium. We present preliminary results of numerical simulations of turbulent mixing layers in a magnetized medium. We developed a MHD code with radiative cooling. The magnetic field is expected to be a controlling factor by suppressing instabilities that lead to the turbulent mixing. Our results suggest that the difference in turbulent mixing in the unmagnetized case as compared to the case of a weak magnetic field, {beta} = Pgas/Pmag {approx} 10, is insignificant. With a more thorough exploration of parameter space, this work will provide more reliable diagnostics of turbulent mixing layers than those available today.

  19. Electrical conductivity of ice VII

    PubMed Central

    Okada, Taku; Iitaka, Toshiaki; Yagi, Takehiko; Aoki, Katsutoshi

    2014-01-01

    It was discovered that a peak appears near a pressure of Pc = 10 GPa in the electrical conductivity of ice VII as measured through impedance spectroscopy in a diamond anvil cell (DAC) during the process of compression from 2 GPa to 40 GPa at room temperature. The activation energy for the conductivity measured in the cooling/heating process between 278 K and 303 K reached a minimum near Pc. Theoretical modelling and molecular dynamics simulations suggest that the origin of this unique peak is the transition of the major charge carriers from the rotational defects to the ionic defects. PMID:25047728

  20. MHD conversion of solar energy. [space electric power system

    NASA Technical Reports Server (NTRS)

    Lau, C. V.; Decher, R.

    1978-01-01

    Low temperature plasmas wherein an alkali metal vapor is a component are uniquely suited to simultaneously absorb solar radiation by coupling to the resonance lines and produce electrical power by the MHD interaction. This work is an examination of the possibility of developing space power systems which take advantage of concentrated solar power to produce electricity. It is shown that efficient cycles in which expansion work takes place at nearly constant top cycle temperature can be devised. The power density of the solar MHD generator is lower than that of conventional MHD generators because of the relatively high seed concentration required for radiation absorption and the lower flow velocity permitted to avoid total pressure losses due to heating.

  1. Effect of Hall Current and Chemical Reaction on MHD Flow Along an Accelerated Porous Flat Plate with Internal Heat Absorption/Generation

    NASA Astrophysics Data System (ADS)

    Kar, M.; Sahoo, S. N.; Dash, G. C.

    2014-05-01

    The effect of the Hall current on unsteady free convection of an electrically conducting incompressible viscous fluid past an accelerated vertical porous plate with internal heat absorption/generation in the presence of various species (H2, CO2, H2O, and NH3) undergoing a first-order chemical reaction in a uniform transverse magnetic field is studied. The role of pertinent parameters characterizing the flow field is discussed. The governing equations are solved using the Hhn(x) functions. It is revealed that heat generation coupled with injection results in a backflow rise. A linearly varying velocity of the plate causes a sudden rise or fall of the velocity in the vicinity of the plate, whereas an asymptotically varying velocity leads to a uniform fall. The presence of chemical reaction increases the secondary velocity by 40%.

  2. Three-dimensional fluid and electrodynamic modeling for MHD DCW channels

    NASA Astrophysics Data System (ADS)

    Liu, B. L.; Lineberry, J. T.; Schmidt, H. J.

    1983-01-01

    A three dimensional, numerical solution for modeling diagonal conducting wall (DCW) magnetohydrodynamic (MHD) generators is developed and discussed. Cross plane gasdynamic and electrodynamic profiles are computed considering coupled MHD flow and electrical phenomena. A turbulent transport model based on the mixing length theory is used to deal with wall roughness generated turbulence effects. The infinitely fine electrode segmentation formulation is applied to simplify the governing electrical equations. Calculations show the development of distorted temperature and velocity profiles under influence of magnetohydrodynamic interaction. Since both sidewall and electrode wall boundary losses are treated, the results furnish a realistic representation of MHD generator behavior.

  3. Three-dimensional MHD simulation of the interaction of the solar wind with the earth's magnetosphere: The generation of field-aligned currents

    SciTech Connect

    Ogino, T.

    1986-06-01

    A global computer simulation of the interaction of the solar wind with the earth's magnetosphere was executed by using a three-dimensional magnetohydrodynamic model. As a result, we were able to reproduce quasi-steady-state magnetospheric configurations and a Birkeland field-aligned current system which depend on the polarity of the z-italic component of the interplanetary magnetic field (IMF). Twin convection cells and a dawn to dusk electric potential of 30--100 kV appeared at the equator in the magnetosphere. Four types of field-aligned currents were observed. Region 1 and 2 field-aligned currents generated for all IMF conditions were 0.6--1.0 x 10/sup 6/ A and 0.15--0.61 x 10/sup 6/ A, respectively, in the total current. Region 1 currents at high latitudes are generated from the field-aligned vorticity at the flanks through a viscous interaction and are strengthened by a twisting of open magnetic field lines in the tail region for southward IMF. On the other hand, the low-latitude region 2 currents probably are generated mainly from the inner pressure gradient of the plasma sheet. The region 1 current obtained from the simulation was in good agreement with an estimate from our theoretical analysis of the localized Alfve-acute-accentn mode. The other two types of field-aligned currents are the dayside magnetopause currents in the dayside cusp region, which increase for northward IMF, and the dayside cusp currents for southward IMF. The cusp currents are associated with a twisting of open magnetic field lines in the magnetopause region.

  4. MHD mixed convection and entropy generation of water-alumina nanofluid flow in a double lid driven cavity with discrete heating

    NASA Astrophysics Data System (ADS)

    Hussain, S.; Mehmood, K.; Sagheer, M.

    2016-12-01

    In the present study, entropy generation due to mixed convection in a partially heated square double lid driven cavity filled with Al2O3 -water nanofluid under the influence of inclined magnetic field is numerically investigated. At the lower wall of the cavity two heat sources are fixed, with the condition that the remaining part of the bottom wall is kept insulated. Top wall and vertically moving walls are maintained at constant cold temperature. Buoyant force is responsible for the flow along with the two moving vertical walls. Governing equations are discretized in space using LBB-stable finite element pair Q2 / P1disc which lead to 3rd and 2nd order accuracy in the L2-norm for the velocity/temperature and pressure, respectively and the fully implicit Crank-Nicolson scheme of 2nd order accuracy is utilized for the temporal discretization. The discretized systems of nonlinear equations are treated by using the Newton method and the associated linear subproblems are solved by means of Guassian elimination method. Numerical results are presented and analyzed by means of streamlines, isotherms, tables and some useful plots. Impacts of emerging parameters on the flow, in specific ranges such as Reynolds number (1 ≤ Re ≤ 100) , Richardson number (1 ≤ Ri ≤ 50) , Hartman number (0 ≤ Ha ≤ 100) , solid volume fraction (0 ≤ ϕ ≤ 0.2) as well as the angles of inclined magnetic field (0 ° ≤ γ ≤ 90 °) are investigated and the findings are exactly of the same order as that of the previously performed analysis. Calculation of average Nusselt number, entropy generation due to heat transfer, fluid friction and magnetic field, total entropy generation, Bejan number and kinetic energy are the main focus of our study.

  5. Transport in EHD flows distinct from HD and MHD flows

    NASA Astrophysics Data System (ADS)

    Kikuchi, H.

    2003-04-01

    vortex line merging of two vortex trails in HD flows and magnetic reconnection in MHD flows. As for energy transport and heat transfer, EHD flows dissipate energy due to electric viscosity and electromagnetic radiation in addition to dissipation due to fluid viscosity and thermal conduction (HD) and magnetic viscosity (MHD). Accordingly, EHD flows produce electric or electromagnetic noise, while HD flows sonic noise and MHD flows magnetic or electromagnetic noise. EHD helical turbulence is capable for large-scale EHD vortex generation by its self-organization, while HD helical turbulence is for large-scale HD vortex generation and MHD helical turbulence for large-scale magnetic field generation. Basically, EHD flows are closely related to dusty plasma, ionization and discharge physics.

  6. Flow Matching Results of an MHD Energy Bypass System on a Supersonic Turbojet Engine Using the Numerical Propulsion System Simulation (NPSS) Environment

    NASA Technical Reports Server (NTRS)

    Benyo, Theresa L.

    2011-01-01

    Flow matching has been successfully achieved for an MHD energy bypass system on a supersonic turbojet engine. The Numerical Propulsion System Simulation (NPSS) environment helped perform a thermodynamic cycle analysis to properly match the flows from an inlet employing a MHD energy bypass system (consisting of an MHD generator and MHD accelerator) on a supersonic turbojet engine. Working with various operating conditions (such as the applied magnetic field, MHD generator length and flow conductivity), interfacing studies were conducted between the MHD generator, the turbojet engine, and the MHD accelerator. This paper briefly describes the NPSS environment used in this analysis. This paper further describes the analysis of a supersonic turbojet engine with an MHD generator/accelerator energy bypass system. Results from this study have shown that using MHD energy bypass in the flow path of a supersonic turbojet engine increases the useful Mach number operating range from 0 to 3.0 Mach (not using MHD) to a range of 0 to 7.0 Mach with specific net thrust range of 740 N-s/kg (at ambient Mach = 3.25) to 70 N-s/kg (at ambient Mach = 7). These results were achieved with an applied magnetic field of 2.5 Tesla and conductivity levels in a range from 2 mhos/m (ambient Mach = 7) to 5.5 mhos/m (ambient Mach = 3.5) for an MHD generator length of 3 m.

  7. MHD-EMP protection guidelines

    SciTech Connect

    Barnes, P.R.; Vance, E.F.

    1992-01-01

    A nuclear detonation at altitudes several hundred kilometers above the earth will severely distort the earth's magnetic field and result in a strong magnetohyrodynamic electromagnetic pulse (MHD-EMP). The geomagnetic disturbance interacts with the soil to induce current and horizontal electric gradients. The geomagnetic disturbance interacts with the soil to induced current and horizontal electric gradients in the earth. MHD-EMP, also called E3 since it is the third component of the high-altitude EMP (HEMP), lasts over 100 s after the exoatmospheric burst. MHD-EMP is similar to solar geomagnetic storms in it's global and low frequency (less than 1 Hz) nature except that E3 can be much more intense with a far shorter duration. When the MHD-EMP gradients are integrated over great distances by power lines, communication cables, or other long conductors, the induced voltages are significant. (The horizontal gradients in the soil are too small to induce major responses by local interactions with facilities.) The long pulse waveform for MHD-EMP-induced currents on long lines has a peak current of 200 A and a time-to-half-peak of 100 s. If this current flows through transformer windings, it can saturate the magnetic circuit and cause 60 Hz harmonic production. To mitigate the effects of MHD-EMP on a facility, long conductors must be isolated from the building and the commercial power harmonics and voltage swings must be addressed. The transfer switch would be expected to respond to the voltage fluctuations as long as the harmonics have not interfered with the switch control circuitry. The major sources of MHD-EMP induced currents are the commercial power lines and neutral; neutral current indirect coupling to the facility power or ground system via the metal fence, powered gate, parking lights, etc; metal water pipes; phone lines; and other long conductors that enter or come near the facility. The major source of harmonics is the commercial power system.

  8. Operational analysis of open-cycle MHD

    NASA Astrophysics Data System (ADS)

    Lippert, T. E.; McCutchan, D. A.

    1980-07-01

    Open cycle magnetohydrodynamic (OCMHD) conceptual power plant designs are studied in the context of a utility system to form a better basis for understanding their design, design requirements, and market possibilities. Based on assumed or projected plant costs and performance characteristics, assumed economics and escalation factors, and one coal supply and delivery scenario, overall and regional OCMHD utility market possibilities are reviewed. Additionally, for one hypothetical utility system a generation expansion plan is developed that includes OCMHD as a baseload power generating station. The impact on generation system economics and operation of alternating selected MHD plant cost and performance characteristics is reviewed. Baseload plant availability is shown as an important plant design consideration, and a general methodology and data base is developed to assess the impact on design and cost of various reliability decisions. An overall plant availability goal is set and the required availabilities of various MHD high technology components are derived to meet the plant goal. The approach is then extended to projecting channel life goals for various plant design configurations and assumptions.

  9. Entropy generation for an axisymmetric MHD flow under thermal non-equilibrium in porous micro duct using a modified lattice Boltzmann method

    NASA Astrophysics Data System (ADS)

    Rabhi, Raja; Amami, Bayssain; Dhahri, Hacen; Mhimid, Abdallah

    2016-12-01

    The present paper centered on a numerical investigation of irreversibility within a porous micro duct subjected to an external oriented magnetic field. At the wall, slip velocity and temperature jump are used as types of boundary conditions. The flow is described by Darcy-Brinkman-Forchheimer model. The Local Thermal Non Equilibrium (LTNE) is adopted including viscous dissipation effects into the energy equation of fluid phase. The study has been carried out for slip-flow regime for wide range of Knudsen numbers, 10-3 ≤ Kn ≤ 10-1 . The obtained governing system equations are solved using the modified Lattice Boltzmann Method (LBM). Efforts are focused on identifying the influence of magnetic field on the entropy generation and Bejan number with a change of various parameters such as Knudsen, Eckert, Biot, Darcy numbers and thermal conductivity ratio. The obtained results show that the irreversibility and the contribution of heat transfer irreversibility and fluid flow irreversibility are strongly affected by the presence of magnetic field.

  10. MHD of Aircraft Re-entry: Limits and Perspectives

    NASA Astrophysics Data System (ADS)

    Seller, G.; Capitelli, M.; Longo, S.; Armenise, I.; Bruno, D.

    2005-05-01

    In the present work, starting from classical MHD scheme, based on Maxwell equations, Euler fluid dynamic equations and generalised Ohm law, a critical study of fluid dynamics, electromagnetism, chemical and physical behaviour of plasma is carried out, and then a aircraft re-entry MHD numerical scheme is implemented. This scheme is used for MHD calculations in different conditions, in the range of low magnetic force and intermediate electrical conductivity. Initial imposed magnetic fields are uniform, but also some cases with coil generated magnetic fields are considered. Calculations of magnetic field and induced currents are extended also inside the blunt body. Results show interesting physical and electromagnetic effects. Comparison with other methods shows possible development in keeping into account other physical and chemical effects.

  11. MHD of Aircraft Re-entry: Limits and Perspectives

    SciTech Connect

    Seller, G.; Capitelli, M.; Longo, S.; Armenise, I.; Bruno, D.

    2005-05-16

    In the present work, starting from classical MHD scheme, based on Maxwell equations, Euler fluid dynamic equations and generalised Ohm law, a critical study of fluid dynamics, electromagnetism, chemical and physical behaviour of plasma is carried out, and then a aircraft re-entry MHD numerical scheme is implemented. This scheme is used for MHD calculations in different conditions, in the range of low magnetic force and intermediate electrical conductivity. Initial imposed magnetic fields are uniform, but also some cases with coil generated magnetic fields are considered. Calculations of magnetic field and induced currents are extended also inside the blunt body. Results show interesting physical and electromagnetic effects. Comparison with other methods shows possible development in keeping into account other physical and chemical effects.

  12. Perturbed Stability Analysis of External Ideal MHD Modes

    NASA Astrophysics Data System (ADS)

    Comer, K. J.; Callen, J. D.; Hegna, C. C.; Garstka, G. D.; Turnbull, A. D.; Garofalo, A. M.; Cowley, S. C.

    2002-11-01

    Traditionally, numerical parameter scans are performed to study the effects of equilibrium shaping and profiles on long wavelength ideal MHD instabilities. Previously, we introduced a new perturbative technique to more efficiently explore these dependencies: changes in delta-W due to small equilibrium variations are found using a perturbation of the energy principle rather than with an eigenvalue-solver instability code. With this approach, the stability properties of similar equilibria can be efficiently explored without generating complete numerical results for every set of parameters (which is time-intensive for accurate representations of several configurations). Here, we apply this approach to toroidal geometry using GATO (an ideal MHD stability code) and experimental equilibria. In particular, we explore ideal MHD stability of external kink modes in the spherical tokamak Pegasus and resistive wall modes in DIII-D.

  13. Aircraft vortex marking program

    NASA Technical Reports Server (NTRS)

    Pompa, M. F.

    1979-01-01

    A simple, reliable device for identifying atmospheric vortices, principally as generated by in-flight aircraft and with emphasis on the use of nonpolluting aerosols for marking by injection into such vortex (-ices) is presented. The refractive index and droplet size were determined from an analysis of aerosol optical and transport properties as the most significant parameters in effecting vortex optimum light scattering (for visual sighting) and visual persistency of at least 300 sec. The analysis also showed that a steam-ejected tetraethylene glycol aerosol with droplet size near 1 micron and refractive index of approximately 1.45 could be a promising candidate for vortex marking. A marking aerosol was successfully generated with the steam-tetraethylene glycol mixture from breadboard system hardware. A compact 25 lb/f thrust (nominal) H2O2 rocket chamber was the key component of the system which produced the required steam by catalytic decomposition of the supplied H2O2.

  14. MHD Integrated Topping Cycle Project

    SciTech Connect

    Not Available

    1992-03-01

    The Magnetohydrodynamics (MHD) Integrated Topping Cycle (ITC) Project represents the culmination of the proof-of-concept (POC) development stage in the US Department of Energy (DOE) program to advance MHD technology to early commercial development stage utility power applications. The project is a joint effort, combining the skills of three topping cycle component developers: TRW, Avco/TDS, and Westinghouse. TRW, the prime contractor and system integrator, is responsible for the 50 thermal megawatt (50 MW{sub t}) slagging coal combustion subsystem. Avco/TDS is responsible for the MHD channel subsystem (nozzle, channel, diffuser, and power conditioning circuits), and Westinghouse is responsible for the current consolidation subsystem. The ITC Project will advance the state-of-the-art in MHD power systems with the design, construction, and integrated testing of 50 MW{sub t} power train components which are prototypical of the equipment that will be used in an early commercial scale MHD utility retrofit. Long duration testing of the integrated power train at the Component Development and Integration Facility (CDIF) in Butte, Montana will be performed, so that by the early 1990's, an engineering data base on the reliability, availability, maintainability and performance of the system will be available to allow scaleup of the prototypical designs to the next development level. This Sixteenth Quarterly Technical Progress Report covers the period May 1, 1991 to July 31, 1991.

  15. MHD mixed convection and entropy generation of nanofluid filled lid driven cavity under the influence of inclined magnetic fields imposed to its upper and lower diagonal triangular domains

    NASA Astrophysics Data System (ADS)

    Selimefendigil, Fatih; Öztop, Hakan F.; Chamkha, Ali J.

    2016-05-01

    In this study, mixed convection of CuO-water nanofluid filled lid driven cavity having its upper and lower triangular domains under the influence of inclined magnetic fields is numerically investigated. The top horizontal wall of the cavity is moving with constant speed of uw with +x direction while no-slip boundary conditions are imposed on the other walls of the cavity. The top wall of the cavity is maintained at constant cold temperature of Tc while the bottom wall is at hot temperature of Th and on the other walls of the cavity are assumed to be adiabatic. The governing equations are solved by using Galerkin weighted residual finite element formulation. Entropy generation is produced by using formulation and integrated with calculated velocities and temperatures. The numerical investigation is performed for a range of parameters: Richardson number (between 0.01 and 100), Hartmann number (between 0 and 50), inclination angle of magnetic field (between 0° and 90°) and solid volume fraction of the nanofluid (between 0 and 0.05). Different combinations of Hartmann numbers and inclination angles of the magnetic fields are imposed in the upper and lower triangular domains of the square cavity. It is observed that the local and averaged heat transfer deteriorates when the Richardson number, Hartmann number of the triangular domains increase. When the Hartmann number and magnetic angle of the upper triangle are increased, more deterioration of the averaged transfer is obtained when compared to lower triangular domain. Local and averaged heat transfer increase as the solid volume fraction of the nanoparticles increases and adding nanoparticles is more effective for the local enhancement of the heat transfer when the heat transfer rate is high and convection is not damped with lowering the Hartmann number. Second law analysis of the system for different combinations of flow parameters is also performed.

  16. A high performance spectral code for nonlinear MHD stability

    SciTech Connect

    Taylor, M.

    1992-09-01

    A new spectral code, NSTAB, has been developed to do nonlinear stability and equilibrium calculations for the magnetohydrodynamic (MHD) equations in three dimensional toroidal geometries. The code has the resolution to test nonlinear stability by calculating bifurcated equilibria directly. These equilibria consist of weak solutions with current sheets near rational surfaces and other less localized modes. Bifurcated equilibria with a pronounced current sheet where the rotational transform crosses unity are calculated for the International Thermonuclear Experimental Reactor (ITER). Bifurcated solutions with broader resonances are found for the LHD stellarator currently being built in Japan and an optimized configuration like the Wendelstein VII-X proposed for construction in Germany. The code is able to handle the many harmonics required to capture the high mode number of these instabilities. NSTAB builds on the highly successful BETAS code, which applies the spectral method to a flux coordinate formulation of the variational principle associated with the MHD equilibrium equations. However, a new residue condition for the location of the magnetic axis has been developed and implemented. This condition is based on the weak formulation of the equations and imposes no constraints on the inner flux surfaces.

  17. Demonstration of the extrinsic coagulation pathway in teleostei: Identification of zebrafish coagulation factor VII

    PubMed Central

    Sheehan, John; Templer, Michael; Gregory, Michael; Hanumanthaiah, Ravikumar; Troyer, Dean; Phan, Thao; Thankavel, Bharath; Jagadeeswaran, Pudur

    2001-01-01

    It is not known whether the mammalian mechanism of coagulation initiation is conserved in fish. Identification of factor VII is critical in providing evidence for such a mechanism. A cDNA was cloned from a zebrafish (teleost) library that predicted a protein with sequence similarity to human factor VII. Factor VII was shown to be present in zebrafish blood and liver by Western blot analysis and immunohistochemistry. Immunodepletion of factor VII from zebrafish plasma selectively inhibited thromboplastin-triggered thrombin generation. Heterologous expression of zebrafish factor VII demonstrated a secreted protein (50 kDa) that reconstituted thromboplastin-triggered thrombin generation in immunodepleted zebrafish plasma. These results suggest conservation of the extrinsic coagulation pathway between zebrafish and humans and add credence to the zebrafish as a model for mammalian hemostasis. The structure of zebrafish factor VIIa predicted by homology modeling was consistent with the overall three-dimensional structure of human factor VIIa. However, amino acid disparities were found in the epidermal growth factor-2/serine protease regions that are present in the human tissue factor–factor VIIa contact surface, suggesting a structural basis for the species specificity of this interaction. In addition, zebrafish factor VII demonstrates that the Gla-EGF-EGF-SP domain structure, which is common to coagulation factors VII, IX, X, and protein C, was present before the radiation of the teleosts from the tetrapods. Identification of zebrafish factor VII significantly narrows the evolutionary window for development of the vertebrate coagulation cascade and provides insight into the structural basis for species specificity in the tissue factor–factor VIIa interaction. PMID:11459993

  18. Little Jiffy, Mark IV

    ERIC Educational Resources Information Center

    Kaiser, Henry F.; Rice, John

    1974-01-01

    In this paper three changes and one new development for the method of exploratory factor analysis (a second generation Little Jiffy) developed by Kaiser are described. Following this short description a step-by-step computer algorithm of the revised method, dubbed Little Jiffy, Mark IV is presented. (MP)

  19. Parametric study of potential early commercial MHD power plants. Task 3: Parameter variation of plant size

    NASA Technical Reports Server (NTRS)

    Hals, F. A.

    1981-01-01

    Plants with a nominal output of 200 and 500 MWe and conforming to the same design configuration as the Task II plant were investigated. This information is intended to permit an assessment of the competitiveness of first generation MHD/steam plants with conventional steam plants over the range of 200 to 1000 MWe. The results show that net plant efficiency of the MHD plant is significantly higher than a conventional steam plant of corresponding size. The cost of electricity is also less for the MHD plant over the entire plant size range. As expected, the cost differential is higher for the larger plant and decreases with plant size. Even at the 200 MWe capacity, however, the differential in COE between the MHD plant and the conventional plant is sufficient attractive to warrant serious consideration. Escalating fuel costs will enhance the competitive position of MHD plants because they can utilize the fuel more efficiently than conventional steam plants.

  20. Kelvin-Helmholtz Unstable Magnetotail Flow Channels: Deceleration and Radiation of MHD Waves

    NASA Astrophysics Data System (ADS)

    Turkakin, H.; Mann, I. R.; Rankin, R.

    2014-12-01

    The Kelvin-Helmholtz instability (KHI) of magnetotail flow channels associated with burstybulk flows (BBFs) is investigated. MHD oscillations of the channel in both kink and sausage modes areinvestigated for KHI, and both the primary and secondary KHIs are found that drive MHD waves. Theseinstabilities are likely to be important for flow channel braking where the KHI removes energy from the flow.At flow speeds above the peak growth rate, the MHD modes excited by KHI develop from surface modesinto propagating modes leading to the radiation of MHD waves from the flow channel. The coupling ofBBF-driven shear flow instabilities to MHD waves presented here represents a new paradigm to explain BBFexcitation of tail flapping. Our model can also explain, for the first time, the generation mechanism for theobservations of waves propagating toward both flanks and emitted from BBF channels in the magnetotail.

  1. System studies of coal fired-closed cycle MHD for central station power plants

    NASA Technical Reports Server (NTRS)

    Zauderer, B.

    1976-01-01

    This paper presents a discussion of the closed cycle MHD results obtained in a recent study of various advanced energy conversion (ECAS) power systems. The study was part of the first phase of this ECAS study. Since this was the first opportunity to evaluate the coal fired closed cycle MHD system, a number of iterations were required to partially optimize the system. The present paper deals with the latter part of the study in which the direct coal fired, MHD topping-steam bottoming cycle was established as the current choice for central station power generation. The emphasis of the paper is on the background assumptions and the conclusions that can be drawn from the closed cycle MHD analysis. The author concludes that closed cycle MHD has efficiencies comparable to that of open cycle MHD and that both systems are considerably more efficient than the other system studies in Phase 1 of the GE ECAS. Its cost will possibly be slightly higher than that of the open cycle MHD system. Also, with reasonable fuel escalation assumptions, both systems can produce lower cost electricity than conventional steam power plants. Suggestions for further work in closed cycle MHD components and systems is made.

  2. Problems in nonlinear resistive MHD

    SciTech Connect

    Turnbull, A.D.; Strait, E.J.; La Haye, R.J.; Chu, M.S.; Miller, R.L.

    1998-12-31

    Two experimentally relevant problems can relatively easily be tackled by nonlinear MHD codes. Both problems require plasma rotation in addition to the nonlinear mode coupling and full geometry already incorporated into the codes, but no additional physics seems to be crucial. These problems discussed here are: (1) nonlinear coupling and interaction of multiple MHD modes near the B limit and (2) nonlinear coupling of the m/n = 1/1 sawtooth mode with higher n gongs and development of seed islands outside q = 1.

  3. Magnetohydrodynamic (MHD) channel corner seal

    DOEpatents

    Spurrier, Francis R.

    1980-01-01

    A corner seal for an MHD duct includes a compressible portion which contacts the duct walls and an insulating portion which contacts the electrodes, sidewall bars and insulators. The compressible portion may be a pneumatic or hydraulic gasket or an open-cell foam rubber. The insulating portion is segmented into a plurality of pieces of the same thickness as the electrodes, insulators and sidewall bars and aligned therewith, the pieces aligned with the insulator being of a different size from the pieces aligned with the electrodes and sidewall bars to create a stepped configuration along the corners of the MHD channel.

  4. Genetics Home Reference: factor VII deficiency

    MedlinePlus

    ... MedlinePlus Encyclopedia: Factor VII Deficiency World Federation of Hemophilia: Treatment Options General Information from MedlinePlus (5 links) ... Patient Support and Advocacy Resources (5 links) Canadian Hemophilia Society Foundation for Women and Girls with Blood ...

  5. 49 CFR 178.703 - Marking of IBCs.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... registered with the Associate Administrator. (vii) The stacking test load in kilograms (kg). For IBCs not... mass in kilograms (kg) marked above the symbol must not exceed the load imposed during the design test...) X—for IBCs meeting Packing Group I, II and III tests; (B) Y—for IBCs meeting Packing Group II...

  6. 49 CFR 178.703 - Marking of IBCs.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    .... Symbols, if used, must be registered with the Associate Administrator. (vii) The stacking test load in... (kg) marked above the symbol must not exceed the load imposed during the design test, as indicated by... successfully tested, as follows: (A) X—for IBCs meeting Packing Group I, II and III tests; (B) Y—for...

  7. 49 CFR 178.703 - Marking of IBCs.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... registered with the Associate Administrator. (vii) The stacking test load in kilograms (kg). For IBCs not... mass in kilograms (kg) marked above the symbol must not exceed the load imposed during the design test...) X—for IBCs meeting Packing Group I, II and III tests; (B) Y—for IBCs meeting Packing Group II...

  8. PREFACE: VII Mexican School on Gravitation and Mathematical Physics

    NASA Astrophysics Data System (ADS)

    Alcubierre Moya, Miguel; García Compeán, Héctor Hugo; Ureña López, Luis Arturo

    2007-07-01

    The present collection of papers was presented during the VII Mexican School on Gravitation and Mathematical Physics, which was held in Playa del Carmen, Quintana Roo, México, from 26 November to 2 December 2006. The Mexican School on Gravitation and Mathematical Physics, sponsored by the Mexican Physical Society, started in 1994 with the purpose of discussing and exchanging current ideas in gravitational physics. Each school has been devoted to a particular subject, and on previous occasions these subjects have covered topics such as supergravity, branes, black holes, the early Universe, observational cosmology, and quantum gravity. At the dawn of the XXI Century, General Relativity has finally become a standard tool in our understanding of numerous astrophysical phenomena. At the same time, the new generation of large interferometric gravitational wave detectors that are just beginning operation holds the promise of finally allowing the detection of gravitational waves and opening a new window on the Universe. However, because of the complexity of the Einstein field equations, the modelling of realistic astrophysical systems and gravitational wave sources can only be done using numerical simulations. Because of this, we have dedicated our VII School to the topic of relativistic astrophysics and numerical relativity. As in all our previous Schools, international leaders in the field were invited to give courses and plenary lectures. The school was complemented with more specialized talks presented in parallel sessions, some of which are included in these proceedings. All the contributions in this volume have been refereed, and they represent a sample of the courses, invited talks and contributed talks presented during our VII School. Our deep gratitude goes to all those who contributed to these proceedings, and to making our VII Mexican School a great success. Miguel Alcubierre Moya, Héctor Hugo García Compeán and Luis Arturo Ureña López Editors

  9. NKG2C/E Marks the Unique Cytotoxic CD4 T Cell Subset, ThCTL, Generated by Influenza Infection.

    PubMed

    Marshall, Nikki B; Vong, Allen M; Devarajan, Priyadharshini; Brauner, Matthew D; Kuang, Yi; Nayar, Ribhu; Schutten, Elizabeth A; Castonguay, Catherine H; Berg, Leslie J; Nutt, Stephen L; Swain, Susan L

    2017-02-01

    CD4 T cells can differentiate into multiple effector subsets, including ThCTL that mediate MHC class II-restricted cytotoxicity. Although CD4 T cell-mediated cytotoxicity has been reported in multiple viral infections, their characteristics and the factors regulating their generation are unclear, in part due to a lack of a signature marker. We show in this article that, in mice, NKG2C/E identifies the ThCTL that develop in the lung during influenza A virus infection. ThCTL express the NKG2X/CD94 complex, in particular the NKG2C/E isoforms. NKG2C/E(+) ThCTL are part of the lung CD4 effector population, and they mediate influenza A virus-specific cytotoxic activity. The phenotype of NKG2C/E(+) ThCTL indicates they are highly activated effectors expressing high levels of binding to P-selectin, T-bet, and Blimp-1, and that more of them secrete IFN-γ and readily degranulate than non-ThCTL. ThCTL also express more cytotoxicity-associated genes including perforin and granzymes, and fewer genes associated with recirculation and memory. They are found only at the site of infection and not in other peripheral sites. These data suggest ThCTL are marked by the expression of NKG2C/E and represent a unique CD4 effector population specialized for cytotoxicity.

  10. Technical support for open-cycle MHD program. Progress report, January-June 1979

    SciTech Connect

    Bomkamp, D. H.

    1980-07-01

    The support program for open-cycle MHD at the Argonne National Laboratory consists of developing the analytical tools needed for investigation of the performance of the major components in the combined-cycle MHD/steam power system. The analytical effort is centered on the primary components of the system that are unique to MHD and, also, on the integration of these analytical models into a model of the entire power-producing system. The present project activities include modeling of the combustor, generator, seed deposition, and formation and decomposition of NO. Parametric studies were performed to evaluate the performance of the U-25B generator and to support the design of the US U-25B generator. Refinements and improvements to the MHD systems code and executive program are described.

  11. MHD-EMP protection guidelines

    SciTech Connect

    Barnes, P.R.; Vance, E.F.

    1992-03-01

    A nuclear detonation at altitudes several hundred kilometers above the earth will severely distort the earth`s magnetic field and result in a strong magnetohyrodynamic electromagnetic pulse (MHD-EMP). The geomagnetic disturbance interacts with the soil to induce current and horizontal electric gradients. The geomagnetic disturbance interacts with the soil to induced current and horizontal electric gradients in the earth. MHD-EMP, also called E3 since it is the third component of the high-altitude EMP (HEMP), lasts over 100 s after the exoatmospheric burst. MHD-EMP is similar to solar geomagnetic storms in it`s global and low frequency (less than 1 Hz) nature except that E3 can be much more intense with a far shorter duration. When the MHD-EMP gradients are integrated over great distances by power lines, communication cables, or other long conductors, the induced voltages are significant. (The horizontal gradients in the soil are too small to induce major responses by local interactions with facilities.) The long pulse waveform for MHD-EMP-induced currents on long lines has a peak current of 200 A and a time-to-half-peak of 100 s. If this current flows through transformer windings, it can saturate the magnetic circuit and cause 60 Hz harmonic production. To mitigate the effects of MHD-EMP on a facility, long conductors must be isolated from the building and the commercial power harmonics and voltage swings must be addressed. The transfer switch would be expected to respond to the voltage fluctuations as long as the harmonics have not interfered with the switch control circuitry. The major sources of MHD-EMP induced currents are the commercial power lines and neutral; neutral current indirect coupling to the facility power or ground system via the metal fence, powered gate, parking lights, etc; metal water pipes; phone lines; and other long conductors that enter or come near the facility. The major source of harmonics is the commercial power system.

  12. Multimegawatt NEP with vapor core reactor MHD

    NASA Astrophysics Data System (ADS)

    Smith, Blair; Knight, Travis; Anghaie, Samim

    2002-01-01

    Efforts at the Innovative Nuclear Space Power and Propulsion Institute have assessed the feasibility of combining gaseous or vapor core reactors with magnetohydrodynamic power generators to provide extremely high quality, high density, and low specific mass electrical power for space applications. Innovative shielding strategies are employed to maintain an effective but relatively low mass shield, which is the most dominating part of multi-megawatt space power systems. The fission driven magnetohydrodynamic generator produces tens of kilowatt DC power at specific mass of less than 0.5 kg/kW for the total power system. The MHD output with minor conditioning is coupled to magnetoplasmadynamic thruster to achieve an overall NEP system specific mass of less than 1.0 kg/kW for power levels above 20 MWe. Few other concepts would allow comparable ensuing payload savings and flexible mission abort options for manned flights to Mars for example. .

  13. System study of an MHD/gas turbine combined-cycle baseload power plant. HTGL report No. 134

    SciTech Connect

    Annen, K.D.

    1981-08-01

    The MHD/gas turbine combined-cycle system has been designed specifically for applications where the availability of cooling water is very limited. The base case systems which were studied consisted of an MHD plant with a gas turbine bottoming plant, and required no cooling water. The gas turbine plant uses only air as its working fluid and receives its energy input from the MHD exhaust gases by means of metal tube heat exchangers. In addition to the base case systems, vapor cycle variation systems were considered which included the addition of a vapor cycle bottoming plant to improve the thermal efficiency. These systems required a small amount of cooling water. The MHD/gas turbine systems were modeled with sufficient detail, using realistic component specifications and costs, so that the thermal and economic performance of the system could be accurately determined. Three cases of MHD/gas turbine systems were studied, with Case I being similar to an MHD/steam system so that a direct comparison of the performances could be made, with Case II being representative of a second generation MHD system, and with Case III considering oxygen enrichment for early commercial applications. The systems are nominally 800 MW/sub e/ to 1000 MW/sub e/ in size. The results show that the MHD/gas turbine system has very good thermal and economic performances while requiring either little or no cooling water. Compared to the MHD/steam system which has a cooling tower heat load of 720 MW, the Base Case I MHD/gas turbine system has a heat rate which is 13% higher and a cost of electricity which is only 7% higher while requiring no cooling water. Case II results show that an improved performance can be expected from second generation MHD/gas turbine systems. Case III results show that an oxygen enriched MHD/gas turbine system may be attractive for early commercial applications in dry regions of the country.

  14. 40 CFR 262.32 - Marking.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... APPLICABLE TO GENERATORS OF HAZARDOUS WASTE Pre-Transport Requirements § 262.32 Marking. (a) Before transporting or offering hazardous waste for transportation off-site, a generator must mark each package of... transportation off-site, a generator must mark each container of 119 gallons or less used in such...

  15. 40 CFR 262.32 - Marking.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... APPLICABLE TO GENERATORS OF HAZARDOUS WASTE Pre-Transport Requirements § 262.32 Marking. (a) Before transporting or offering hazardous waste for transportation off-site, a generator must mark each package of... transportation off-site, a generator must mark each container of 119 gallons or less used in such...

  16. 40 CFR 262.32 - Marking.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... APPLICABLE TO GENERATORS OF HAZARDOUS WASTE Pre-Transport Requirements § 262.32 Marking. (a) Before transporting or offering hazardous waste for transportation off-site, a generator must mark each package of... transportation off-site, a generator must mark each container of 119 gallons or less used in such...

  17. 40 CFR 262.32 - Marking.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... APPLICABLE TO GENERATORS OF HAZARDOUS WASTE Pre-Transport Requirements § 262.32 Marking. (a) Before transporting or offering hazardous waste for transportation off-site, a generator must mark each package of... transportation off-site, a generator must mark each container of 119 gallons or less used in such...

  18. 40 CFR 262.32 - Marking.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... APPLICABLE TO GENERATORS OF HAZARDOUS WASTE Pre-Transport Requirements § 262.32 Marking. (a) Before transporting or offering hazardous waste for transportation off-site, a generator must mark each package of... transportation off-site, a generator must mark each container of 119 gallons or less used in such...

  19. Initial Flow Matching Results of MHD Energy Bypass on a Supersonic Turbojet Engine Using the Numerical Propulsion System Simulation (NPSS) Environment

    NASA Technical Reports Server (NTRS)

    Benyo, Theresa L.

    2010-01-01

    Preliminary flow matching has been demonstrated for a MHD energy bypass system on a supersonic turbojet engine. The Numerical Propulsion System Simulation (NPSS) environment was used to perform a thermodynamic cycle analysis to properly match the flows from an inlet to a MHD generator and from the exit of a supersonic turbojet to a MHD accelerator. Working with various operating conditions such as the enthalpy extraction ratio and isentropic efficiency of the MHD generator and MHD accelerator, interfacing studies were conducted between the pre-ionizers, the MHD generator, the turbojet engine, and the MHD accelerator. This paper briefly describes the NPSS environment used in this analysis and describes the NPSS analysis of a supersonic turbojet engine with a MHD generator/accelerator energy bypass system. Results from this study have shown that using MHD energy bypass in the flow path of a supersonic turbojet engine increases the useful Mach number operating range from 0 to 3.0 Mach (not using MHD) to an explored and desired range of 0 to 7.0 Mach.

  20. A base substitution in the exon of a collagen gene causes alternative splicing and generates a structurally abnormal polypeptide in a patient with Ehlers-Danlos syndrome type VII.

    PubMed Central

    Weil, D; D'Alessio, M; Ramirez, F; de Wet, W; Cole, W G; Chan, D; Bateman, J F

    1989-01-01

    An unusual splicing mutation has been characterized in the pro alpha 1(I) collagen gene of a sporadic case of Ehlers-Danlos Syndrome Type VII. Cloning of primer extended cDNA in conjunction with R-looping experiments established that nearly half of the pro alpha 1(I) collagen gene transcripts are abnormally spliced, for they lack exon 6 sequences. Analysis of cloned genomic fragments revealed that one of the proband's alleles displays the substitution of an A for a G in the last nucleotide of exon 6. The change converts the normal Met (ATG) codon to Ile (ATA) and, in addition, obliterates a NcoI restriction site. The latter event was exploited to demonstrate the de novo nature of the mutation since DNA from the unaffected parents was fully digested with the enzyme, after in vitro amplification by the polymerase chain reaction. Further confirmation of the missplicing was obtained by transient expression into animal cells of allelic minigene constructs. Finally, Western blot analysis of cyanogen bromide cleaved collagen and nucleotide sequencing of appropriately selected cDNA clones demonstrated the production of relatively low amounts of correctly spliced molecules harboring the Ile substitution, as well. Images PMID:2767050

  1. MHD Turbulence and Magnetic Dynamos

    NASA Technical Reports Server (NTRS)

    Shebalin, John V

    2014-01-01

    Incompressible magnetohydrodynamic (MHD) turbulence and magnetic dynamos, which occur in magnetofluids with large fluid and magnetic Reynolds numbers, will be discussed. When Reynolds numbers are large and energy decays slowly, the distribution of energy with respect to length scale becomes quasi-stationary and MHD turbulence can be described statistically. In the limit of infinite Reynolds numbers, viscosity and resistivity become zero and if these values are used in the MHD equations ab initio, a model system called ideal MHD turbulence results. This model system is typically confined in simple geometries with some form of homogeneous boundary conditions, allowing for velocity and magnetic field to be represented by orthogonal function expansions. One advantage to this is that the coefficients of the expansions form a set of nonlinearly interacting variables whose behavior can be described by equilibrium statistical mechanics, i.e., by a canonical ensemble theory based on the global invariants (energy, cross helicity and magnetic helicity) of ideal MHD turbulence. Another advantage is that truncated expansions provide a finite dynamical system whose time evolution can be numerically simulated to test the predictions of the associated statistical mechanics. If ensemble predictions are the same as time averages, then the system is said to be ergodic; if not, the system is nonergodic. Although it had been implicitly assumed in the early days of ideal MHD statistical theory development that these finite dynamical systems were ergodic, numerical simulations provided sufficient evidence that they were, in fact, nonergodic. Specifically, while canonical ensemble theory predicted that expansion coefficients would be (i) zero-mean random variables with (ii) energy that decreased with length scale, it was found that although (ii) was correct, (i) was not and the expected ergodicity was broken. The exact cause of this broken ergodicity was explained, after much

  2. Performance calculations for 1000 MWe MHD/steam power plants

    NASA Technical Reports Server (NTRS)

    Pian, C. C. P.

    1981-01-01

    The effects of MHD generator operating conditions and constraints on the performance of MHD/steam power plants are investigated. Power plants using high temperature combustion air preheat (2500 F) and plants using intermediate temperature preheat (1100 F) with oxygen enrichment are considered. Variations of these two types of power plants are compared on the basis of fixed total electrical output (1000 MWe). Results are presented to show the effects of generator plant length and level of oxygen enrichment on the plant thermodynamic efficiency and on the required generator mass flow rate. Factors affecting the optimum levels of oxygen enrichment are analyzed. It is shown that oxygen enrichment can reduce magnet stored energy requirement.

  3. Enhanced Born charges in III-VII, IV-VII2 , and V-VII3 compounds

    NASA Astrophysics Data System (ADS)

    Du, Mao-Hua; Singh, David J.

    2010-07-01

    We report electronic-structure and lattice dynamics calculations on selected III-VII, IV-VII2 , and V-VII3 compounds. The common characteristic of these largely ionic compounds is that their outmost cation- s states are fully occupied and thus the conduction-band states are derived from the more spatially extended cation- p states, resulting in significant cross-band-gap hybridization, which enhances Born effective charges substantially. The large Born charges cause large splitting between longitudinal and transverse optic phonon modes and large static dielectric constants resulting mostly from the lattice contribution. This can lead to effective screening of defects and impurities that would otherwise be strong carrier traps and recombination centers and may therefore have positive effects on the carrier transport properties in radiation detectors based on these soft-lattice halides.

  4. Magnetic levitation and MHD propulsion

    NASA Astrophysics Data System (ADS)

    Tixador, P.

    1994-04-01

    Magnetic levitation and MHD propulsion are now attracting attention in several countries. Different superconducting MagLev and MHD systems will be described concentrating on, above all, the electromagnetic aspect. Some programmes occurring throughout the world will be described. Magnetic levitated trains could be the new high speed transportation system for the 21st century. Intensive studies involving MagLev trains using superconductivity have been carried out in Japan since 1970. The construction of a 43 km long track is to be the next step. In 1991 a six year programme was launched in the United States to evaluate the performances of MagLev systems for transportation. The MHD (MagnetoHydroDynamic) offers some interesting advantages (efficiency, stealth characteristics, ...) for naval propulsion and increasing attention is being paid towards it nowadays. Japan is also up at the top with the tests of Yamato I, a 260 ton MHD propulsed ship. Depuis quelques années nous assistons à un redémarrage de programmes concernant la lévitation et la propulsion supraconductrices. Différents systèmes supraconducteurs de lévitation et de propulsion seront décrits en examinant plus particulièrement l'aspect électromagnétique. Quelques programmes à travers le monde seront abordés. Les trains à sustentation magnétique pourraient constituer un nouveau mode de transport terrestre à vitesse élevée (500 km/h) pour le 21^e siècle. Les japonais n'ont cessé de s'intéresser à ce système avec bobine supraconductrice. Ils envisagent un stade préindustriel avec la construction d'une ligne de 43 km. En 1991 un programme américain pour une durée de six ans a été lancé pour évaluer les performances des systèmes à lévitation pour le transport aux Etats Unis. La MHD (Magnéto- Hydro-Dynamique) présente des avantages intéressants pour la propulsion navale et un regain d'intérêt apparaît à l'heure actuelle. Le japon se situe là encore à la pointe des d

  5. Electrical characteristics of a seawater MHD thruster. Final report

    SciTech Connect

    Tempelmeyer, K.E.

    1990-06-01

    There is renewed interest in the application of the magnetohydrodynamic (MHD) propulsion concept to marine propulsion. However, there is almost no experimental information concerning the major physical processes which will occur in a seawater MHD propulsion unit, such as (1) the seawater electrolysis process at operational conditions needed for ship propulsion, (2) the effects of bubble formation on the performance of a seawater thruster and (3) the effectiveness of the MHD interaction in seawater. Small scale tests of an MHD type channel but without an applied magnetic field have been carried out to provide information about the first two of these areas (1) seawater electrolysis and (2) the effect of the H2 bubbles generated during the electrolysis of seawater. Current/voltage characteristics were obtained with different electrode materials for current densities up to 0.3 amp/sq cm. The effect of bubble formation on the channel current has been assessed over a range of operating conditions. Long-duration tests to 100 hrs have been made to provide information on electrode durability and long-term operational problems.

  6. 3D MHD Models of Active Region Loops

    NASA Technical Reports Server (NTRS)

    Ofman, Leon

    2004-01-01

    Present imaging and spectroscopic observations of active region loops allow to determine many physical parameters of the coronal loops, such as the density, temperature, velocity of flows in loops, and the magnetic field. However, due to projection effects many of these parameters remain ambiguous. Three dimensional imaging in EUV by the STEREO spacecraft will help to resolve the projection ambiguities, and the observations could be used to setup 3D MHD models of active region loops to study the dynamics and stability of active regions. Here the results of 3D MHD models of active region loops are presented, and the progress towards more realistic 3D MHD models of active regions. In particular the effects of impulsive events on the excitation of active region loop oscillations, and the generation, propagations and reflection of EIT waves are shown. It is shown how 3D MHD models together with 3D EUV observations can be used as a diagnostic tool for active region loop physical parameters, and to advance the science of the sources of solar coronal activity.

  7. Performance characteristics of an MHD (Magnetohydrodynamic) pilot plant electrostatic precipitator

    NASA Astrophysics Data System (ADS)

    Lindner, J. S.; Jang, P. R.; Okhuysen, W. P.; Holt, J. K.

    In magnetohydrodynamic (MHD) power generation, a seed material, normally K2CO3, is added to enhance the conductivity of the coal-fired gas stream. The plasma is passed through a magnetic field and electricity is produced by the Hall effect. Future large scale MHD facilities are expected to be more efficient than conventional coal-fired power plants not only because of the dc electricity produced but also from increased heat recovery owing to the large (3000 K) combustion temperatures employed. There is; however, a finite cost for the seed material and the resulting K2SO4 particles (SO2 emissions are minimized by combination with seed potassium) must be collected, converted back to K2CO3 or KCO2H, and recycled back to the combustor. The performance characteristics of the MHD electrostatic precipitator (ESP) are therefore, of interest. We describe Mie scattering and electric field measurements on an MHD pilot scale ESP located at the Coal Fire Flow Facility (CFFF) at the University of Tennessee Space Institute. Results are reported for the determination of near-real-time collection efficiencies, the variation of the ESP performance with seed percentage, and initial studies on the extent of particle re-entrainment.

  8. Integral Constraints and MHD Stability

    NASA Astrophysics Data System (ADS)

    Jensen, T. H.

    2003-10-01

    Determining stability of a plasma in MHD equilibrium, energetically isolated by a conducting wall, requires an assumption on what governs the dynamics of the plasma. One example is the assumption that the plasma obeys ideal MHD, leading to the well known ``δ W" criteria [I. Bernstein, et al., Proc. Roy. Soc. London A244, 17 (1958)]. A radically different approach was used by Taylor [J.B. Taylor, Rev. Mod. Phys. 58, 741 (1986)] in assuming that the dynamics of the plasma is restricted only by the requirement that helicity, an integral constant associated with the plasma, is conserved. The relevancy of Taylor's assumption is supported by the agreement between resulting theoretical results and experimental observations. Another integral constraint involves the canonical angular momentum of the plasma particles. One consequence of using this constraint is that tokamak plasmas have no poloidal current in agreement with some current hole tokamak observations [T.H. Jensen, Phys. Lett. A 305, 183 (2002)].

  9. Magnetohydrodynamics (MHD) Engineering Test Facility (ETF) 200 MWe power plant. Design Requirements Document (DRD)

    NASA Technical Reports Server (NTRS)

    Rigo, H. S.; Bercaw, R. W.; Burkhart, J. A.; Mroz, T. S.; Bents, D. J.; Hatch, A. M.

    1981-01-01

    A description and the design requirements for the 200 MWe (nominal) net output MHD Engineering Test Facility (ETF) Conceptual Design, are presented. Performance requirements for the plant are identified and process conditions are indicated at interface stations between the major systems comprising the plant. Also included are the description, functions, interfaces and requirements for each of these major systems. The lastest information (1980-1981) from the MHD technology program are integrated with elements of a conventional steam electric power generating plant.

  10. The Biermann catastrophe of numerical MHD

    NASA Astrophysics Data System (ADS)

    Graziani, C.; Tzeferacos, P.; Lee, D.; Lamb, D. Q.; Weide, K.; Fatenejad, M.; Miller, J.

    2016-05-01

    The Biermann Battery effect is frequently invoked in cosmic magnetogenesis and studied in High-Energy Density laboratory physics experiments. Unfortunately, direct implementation of the Biermann effect in MHD codes is known to produce unphysical magnetic fields at shocks whose value does not converge with resolution. We show that this convergence breakdown is due to naive discretization, which fails to account for the fact that discretized irrotational vector fields have spurious solenoidal components that grow without bound near a discontinuity. We show that careful consideration of the kinetics of ion viscous shocks leads to a formulation of the Biermann effect that gives rise to a convergent algorithm. We note a novel physical effect a resistive magnetic precursor in which Biermann-generated field in the shock “leaks” resistively upstream. The effect appears to be potentially observable in experiments at laser facilities.

  11. α(1,3) Fucosyltransferases IV and VII are essential for the initial recruitment of basophils in chronic allergic inflammation.

    PubMed

    Saeki, Kazumi; Satoh, Takahiro; Yokozeki, Hiroo

    2013-09-01

    Basophils act as initiator cells for the development of IgE-mediated chronic allergic inflammation (IgE-CAI). However, detailed mechanisms of initial recruitment of basophils into the skin have yet to be clarified. Selectins mediate leukocyte capture and rolling on the vascular endothelium for extravasation. Counter-receptor activity of selectins is regulated by α(1, 3) fucosyltransferases (FTs) IV and VII. To clarify the contribution of selectin ligands regulated by FTs for initial basophil recruitment, IgE-CAI was induced in mice deficient in FT-IV and/or FT-VII genes. Although FT-IV(-/-) and FT-VII(-/-) mice exhibited comparable skin responses to wild-type mice, the FT-IV(-/-)/FT-VII(-/-) mice showed significantly impaired inflammation. Although the transfer of basophils to FcRγ(-/-) mice induced IgE-CAI, this induction was completely absent when basophils from FT-IV(-/-)/FT-VII(-/-) mice were transferred. L-selectin, but not P- and E-selectin, blocking Abs inhibited skin inflammation in vivo. P-selectin glycoprotein-1 (PSGL-1) antibody also ameliorated skin inflammation, and basophils were bound to L-selectin in a PSGL-1-dependent manner, which was regulated by FT-IV/VII. Functional PSGL-1 generated by basophil FT-IV/VII and its subsequent binding to L-selectin could be one of the essential steps required for initial basophil recruitment and the development of IgE-CAI in mice.

  12. Role of lysine and tryptophan residues in the biological activity of toxin VII (Ts gamma) from the scorpion Tityus serrulatus.

    PubMed

    Hassani, O; Mansuelle, P; Cestèle, S; Bourdeaux, M; Rochat, H; Sampieri, F

    1999-02-01

    Toxin VII (TsVII), also known as Ts gamma, is the most potent neurotoxin in the venom of the Brazilian scorpion Tityus serrulatus. It has been purified to homogeneity using a new fast and efficient method. Chemical modification of TsVII with the tryptophan-specific reagent o-nitrophenylsulfenyl chloride yielded three modified derivatives (residues Trp39, Trp50 and Trp54). Acetylation of TsVII mostly generated the monoacetylated Lys12 derivative. No side reactions were detected, as indicated by endoproteinase Lys-C peptide mapping, Edman degradation and electrospray mass spectrometry. Circular dichroism and fluorimetric measurements showed that none of the chemical modifications altered the overall structure of the derivatives. The acetylation of Lys12 or the sulfenylation of Trp39 or Trp54 led to a loss of both toxicity in mice and apparent binding affinity for rat brain and cockroach synaptosomal preparations. Sulfenylation of Trp50, however, moderately affected the toxicity of TsVII in mice and had almost no effect on its binding properties. A 3-dimensional model of TsVII was constructed by homology modeling. It suggests that the most reactive residues (Lys12 and Trp39 and Trp54) are all important in the functional disruption of neuronal sodium channels by TsVII, and are close to each other in the hydrophobic conserved region.

  13. Vorticity equation for MHD fast waves in geospace environment

    NASA Technical Reports Server (NTRS)

    Yamauchi, M.; Lundin, R.; Lui, A. T. Y.

    1993-01-01

    The MHD vorticity equation is modified in order to apply it to nonlinear MHD fast waves or shocks when their extent along the magnetic field is limited. Field-aligned current (FAC) generation is also discussed on the basis of this modified vorticity equation. When the wave normal is not aligned to the finite velocity convection and the source region is spatially limited, a longitudinal polarization causes a pair of plus and minus charges inside the compressional plane waves or shocks, generating a pair of FACs. This polarization is not related to the separation between the electrons and ions caused by their difference in mass, a separation which is inherent to compressional waves. The resultant double field-aligned current structure exists both with and without the contributions from curvature drift, which is questionable in terms of its contribution to vorticity change from the viewpoint of single-particle motion.

  14. NaK-nitrogen liquid metal MHD converter tests at 30 kw

    NASA Technical Reports Server (NTRS)

    Cerini, D. J.

    1974-01-01

    The feasibility of electrical power generation with an ambient temperature liquid-metal MHD separator cycle is demonstrated by tests in which a NaK-nitrogen LM-MHD converter was operated at nozzle inlet pressures ranging from 100 to 165 N/sq cm, NaK flow rates from 46 to 72 kg/sec, and nitrogen flow rates from 2.4 to 3.8 kg/sec. The generator was operated as an eight-phase linear induction generator, with two of the eight phases providing magnetic field compensation to minimized electrical end losses at the generator channel inlet and exit.

  15. ORNL Resonance Evaluation for ENDF/B-VII.1

    SciTech Connect

    Leal, Luiz C; Guber, Klaus H; Wiarda, Dorothea; Arbanas, Goran; Dunn, Michael E

    2012-01-01

    Cross-section evaluations in the resonance region are performed at Oak Ridge National Laboratory (ORNL) with the computer code SAMMY based on formalisms derived from the R-matrix theory. Resonance parameters (RPs) obtained in the evaluation, combined with resonance formalism, replicate a regression of the experimental data. The RPs are also used to generate cross-section data for neutron transport calculations in analyses of nuclear reactor design and nuclear criticality safety. In addition to generating RPs, the evaluation also generates the resonance parameter covariance (RPC) data. Several ORNL resonance evaluations, including RPs and RPCs, were incorporated in the recently released US-evaluated nuclear data library, ENDF/B-VII.1. A brief summary of the RPs and RPCs evaluated at ORNL is given.

  16. Blister-inducing antibodies target multiple epitopes on collagen VII in mice

    PubMed Central

    Csorba, Kinga; Chiriac, Mircea Teodor; Florea, Florina; Ghinia, Miruna Georgiana; Licarete, Emilia; Rados, Andreea; Sas, Alexandra; Vuta, Vlad; Sitaru, Cassian

    2014-01-01

    Epidermolysis bullosa acquisita (EBA) is an autoimmune subepidermal blistering disease of mucous membranes and the skin caused by autoantibodies against collagen VII. In silico and wet laboratory epitope mapping studies revealed numerous distinct epitopes recognized by EBA patients' autoantibodies within the non-collagenous (NC)1 and NC2 domains of collagen VII. However, the distribution of pathogenic epitopes on collagen VII has not yet been described. In this study, we therefore performed an in vivo functional epitope mapping of pathogenic autoantibodies in experimental EBA. Animals (n = 10/group) immunized against fragments of the NC1 and NC2 domains of collagen VII or injected with antibodies generated against the same fragments developed to different extent experimental EBA. Our results demonstrate that antibodies targeting multiple, distinct epitopes distributed over the entire NC1, but not NC2 domain of collagen VII induce blistering skin disease in vivo. Our present findings have crucial implications for the development of antigen-specific B- and T cell-targeted therapies in EBA. PMID:25091020

  17. Methods for Processing ENDF/B-VII with NJOY

    SciTech Connect

    MacFarlane, R.E.; Kahler, A.C.

    2010-12-15

    The NJOY Nuclear Data Processing System is widely used to convert evaluations in the Evaluated Nuclear Data Files (ENDF) format into forms useful for practical applications such as fission and fusion reactor analysis, stockpile stewardship calculations, criticality safety, radiation shielding, nuclear waste management, nuclear medicine procedures, and more. This paper provides a description of the system's capabilities, summary descriptions of the methods used, and information on how to use the code to process the modern evaluated nuclear data files from ENDF/B-VII. It begins with the generation of pointwise libraries, including reaction and resonance reconstruction, Doppler broadening, radiation heating and damage, thermal scattering data, unresolved resonance data, and gas production. It then reviews the production of libraries for the continuous-energy Monte Carlo code MCNP, multigroup neutron, photon, and particle cross sections and matrices, and photon interaction data. The generation of uncertainty information for ENDF data is discussed, including new capabilities for calculating covariances of resonance data, angular distributions, energy distributions, and radioactive nuclide production. NJOY's ability to prepare thermal scattering data evaluations for bound moderators (which was used during the preparation of the ENDF/B-VII library) is described. The strong plotting capabilities of NJOY are summarized. Many examples of black and white and color Postscript plots are included throughout the paper. The capabilities of NJOY to output multigroup data in several different formats to suit various applications is reviewed. Finally, a section is included that summarizes the history of the development of the NJOY system over the last 37 years.

  18. Methods for Processing ENDF/B-VII with NJOY

    NASA Astrophysics Data System (ADS)

    MacFarlane, R. E.; Kahler, A. C.

    2010-12-01

    The NJOY Nuclear Data Processing System is widely used to convert evaluations in the Evaluated Nuclear Data Files (ENDF) format into forms useful for practical applications such as fission and fusion reactor analysis, stockpile stewardship calculations, criticality safety, radiation shielding, nuclear waste management, nuclear medicine procedures, and more. This paper provides a description of the system's capabilities, summary descriptions of the methods used, and information on how to use the code to process the modern evaluated nuclear data files from ENDF/B-VII. It begins with the generation of pointwise libraries, including reaction and resonance reconstruction, Doppler broadening, radiation heating and damage, thermal scattering data, unresolved resonance data, and gas production. It then reviews the production of libraries for the continuous-energy Monte Carlo code MCNP, multigroup neutron, photon, and particle cross sections and matrices, and photon interaction data. The generation of uncertainty information for ENDF data is discussed, including new capabilities for calculating covariances of resonance data, angular distributions, energy distributions, and radioactive nuclide production. NJOY's ability to prepare thermal scattering data evaluations for bound moderators (which was used during the preparation of the ENDF/B-VII library) is described. The strong plotting capabilities of NJOY are summarized. Many examples of black&white and color Postscript plots are included throughout the paper. The capabilities of NJOY to output multigroup data in several different formats to suit various applications is reviewed. Finally, a section is included that summarizes the history of the development of the NJOY system over the last 37 years.

  19. 77 FR 64400 - Order of Succession for HUD Region VII

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-19

    ... URBAN DEVELOPMENT Order of Succession for HUD Region VII AGENCY: Office of Field Policy and Management... Succession for the Kansas City Regional Office and its Field Offices (Region VII). This Order of Succession supersedes all previous Orders of Succession for HUD Region VII. DATES: Effective Date: October 9, 2012....

  20. 29 CFR 1601.93 - Opinions-title VII.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 4 2012-07-01 2012-07-01 false Opinions-title VII. 1601.93 Section 1601.93 Labor Regulations Relating to Labor (Continued) EQUAL EMPLOYMENT OPPORTUNITY COMMISSION PROCEDURAL REGULATIONS Title VII Interpretations and Opinions by the Commission § 1601.93 Opinions—title VII. Only the following may be relied upon as a “written...

  1. 29 CFR 1601.93 - Opinions-title VII.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 4 2010-07-01 2010-07-01 false Opinions-title VII. 1601.93 Section 1601.93 Labor Regulations Relating to Labor (Continued) EQUAL EMPLOYMENT OPPORTUNITY COMMISSION PROCEDURAL REGULATIONS Title VII Interpretations and Opinions by the Commission § 1601.93 Opinions—title VII. Only the following may be relied upon as a “written...

  2. 40 CFR Appendix Vii to Part 600 - [Reserved

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 30 2014-07-01 2014-07-01 false VII Appendix VII to Part 600 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) ENERGY POLICY FUEL ECONOMY AND GREENHOUSE GAS EXHAUST EMISSIONS OF MOTOR VEHICLES Appendix VII to Part 600...

  3. 40 CFR Appendix Vii to Part 600 - [Reserved

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 31 2012-07-01 2012-07-01 false VII Appendix VII to Part 600 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) ENERGY POLICY FUEL ECONOMY AND GREENHOUSE GAS EXHAUST EMISSIONS OF MOTOR VEHICLES Appendix VII to Part 600...

  4. Very low activated factor VII and reduced factor VII antigen in familial abetalipoproteinaemia.

    PubMed

    Miller, G J; Mitropoulos, K A; Nanjee, M N; Howarth, D J; Martin, J C; Esnouf, M P; Reeves, B E; Miller, N E; Cooper, J A

    1998-08-01

    Abetalipoproteinaemia is a rare disorder of apolipoprotein B metabolism associated with extremely low plasma concentrations of triglyceride. To discover whether the general positive association between factor VII and triglyceride levels extends to this condition, 5 patients were compared with 18 controls. All patients had a triglyceride below 100 micromol/l. Plasma unesterified fatty acid concentration was normal. Although factor IX activity was only slightly reduced (mean 88% standard) and factor IX antigen was normal, mean activated factor VII in patients was strikingly reduced to 34% of that in controls, a level similar to that found in haemophilia B. The patients' mean factor VII activity and factor VII antigen were also significantly reduced to 54% and 63% of those in controls, respectively. Mean factor XI activity and tissue factor pathway inhibitor activity were reduced in patients to 70% and 75% of control values respectively, while factor XII, factor XI antigen, factor X, prothrombin and protein C were normal.

  5. Intravenous pamidronate in osteogenesis imperfecta type VII.

    PubMed

    Cheung, Moira S; Glorieux, Francis H; Rauch, Frank

    2009-03-01

    Cyclical intravenous treatment with pamidronate is widely used to treat osteogenesis imperfecta (OI) types I, III, and IV, which are due to dominant mutations affecting collagen type I alpha chains. There is no information about the effects of pamidronate in children with OI type VII, an autosomal-recessive form of OI caused by a mutation in the cartilage-associated protein gene. In this retrospective single-center study, we compared the effects of pamidronate in four girls with OI type VII (age range 3.9-12.7 years) to those in eight girls with OI types caused by collagen type I mutations who were matched for age and disease severity. During 3 years of pamidronate therapy, lumbar spine areal bone mineral density increased and lumbar vertebral bodies improved in shape in patients with OI type VII. Other outcomes such as fracture rates and mobility scores did not show statistically significant changes in this small study cohort. There were no significant side effects noted during the time of follow-up. Thus, intravenous treatment with pamidronate seems to be safe and of some benefit in patients with OI type VII.

  6. Leveraging Information Technology. Track VII: Outstanding Applications.

    ERIC Educational Resources Information Center

    CAUSE, Boulder, CO.

    Eight papers from the 1987 CAUSE conference's Track VII, Outstanding Applications, are presented. They include: "Image Databases in the University" (Reid Kaplan and Gordon Mathieson); "Using Information Technology for Travel Management at the University of Michigan" (Robert E. Russell and John C. Hufziger); "On-Line Access…

  7. Emission line spectra of S VII ? S XIV in the 20 ? 75 ? wavelength region

    SciTech Connect

    Lepson, J K; Beiersdorfer, P; Behar, E; Kahn, S M

    2004-08-06

    As part of a larger project to complete a comprehensive catalogue of astrophysically relevant emission lines in support of new-generation X-ray observatories using the Lawrence Livermore electron beam ion traps EBIT-I and EBIT-II, the authors present observations of sulfur lines in the soft X-ray and extreme ultraviolet regions. The database includes wavelength measurements with standard errors, relative intensities, and line assignments for 127 transitions of S VII through S XIV between 20 and 75 {angstrom}. The experimental data are complemented with a full set of calculations using the Hebrew University Lawrence Livermore Atomic Code (HULLAC). A comparison of the laboratory data with Chandra measurements of Procyon allows them to identify S VII-S XI lines.

  8. Heating of solar and stellar chromospheres and coronae by MHD waves

    NASA Technical Reports Server (NTRS)

    Musielak, Z. E.

    1992-01-01

    The two general classes of models that deal with the required heating of stellar chromospheres and coronae assume that outer stellar atmospheres are heated by hydrodynamic or by magnetohydrodynamic (MHD) waves and that these waves are generated by turbulent motions in the stellar convection zones. This paper considers the types of MHD waves and the source of these waves in stars like sun, the efficiency of the generation of MHD waves, and the manner of propagation and energy dissipation of MHD waves. It is shown that the basic criteria for the validity of any theory of MHD wave heating must account for the mean level of heating observed in stellar chromospheres and coronae, and for the range of radiative losses observed for a given spectral type. It is also required that the MHD wave heating theory accounts for the existence of inhomogeneities in stellar atmospheres. The results obtained indicate that magnetic tube waves might supply enough energy for the chromospheric and coronal heating and might also account for the observed range of variations of stellar radiative losses for a given spectral type.

  9. MHD Integrated Topping Cycle Project

    SciTech Connect

    Not Available

    1992-07-01

    This eighteenth quarterly technical progress report of the MHD Integrated Topping cycle Project presents the accomplishments during the period November 1, 1991 to January 31, 1992. The precombustor is fully assembled. Manufacturing of all slagging stage components has been completed. All cooling panels were welded in place and the panel/shell gap was filled with RTV. Final combustor assembly is in progress. The low pressure cooling subsystem (LPCS) was delivered to the CDIF. Second stage brazing issues were resolved. The construction of the two anode power cabinets was completed.

  10. Ceramic component for MHD electrode

    DOEpatents

    Marchant, David D.; Bates, Junior L.

    1981-01-01

    A ceramic component which exhibits electrical conductivity down to near room temperatures has the formula: Hf.sub.x In.sub.y A.sub.z O.sub.2 where x=0.1 to 0.4, y=0.3 to 0.6, z=0.1 to 0.4 and A is a lanthanide rare earth or yttrium. The component is suitable for use in the fabrication of MHD electrodes or as the current leadout portion of a composite electrode with other ceramic components.

  11. Ceramic components for MHD electrode

    DOEpatents

    Marchant, D.D.

    A ceramic component which exhibits electrical conductivity down to near room temperatures has the formula: Hf/sub x/In/sub y/A/sub z/O/sub 2/ where x = 0.1 to 0.4, y = 0.3 to 0.6, z = 0.1 to 0.4 and A is a lanthanide rare earth or yttrium. The component is suitable for use in the fabrication of MHD electrodes or as the current leadout portion of a composite electrode with other ceramic components.

  12. Global MHD model of the earth's magnetosphere

    NASA Technical Reports Server (NTRS)

    Wu, C. C.

    1983-01-01

    A global MHD model of the earth's magnetosphere is defined. An introduction to numerical methods for solving the MHD equations is given with emphasis on the shock-capturing technique. Finally, results concerning the shape of the magnetosphere and the plasma flows inside the magnetosphere are presented.

  13. An MHD model of the earth's magnetosphere

    NASA Technical Reports Server (NTRS)

    Wu, C. C.

    1985-01-01

    It is pointed out that the earth's magnetosphere arises from the interaction of the solar wind with the earth's geomagnetic field. A global magnetohydrodynamics (MHD) model of the earth's magnetosphere has drawn much attention in recent years. In this model, MHD equations are used to describe the solar wind interaction with the magnetosphere. In the present paper, some numerical aspects of the model are considered. Attention is given to the ideal MHD equations, an equation of state for the plasma, the model as an initial- and boundary-value problem, the shock capturing technique, computational requirements and techniques for global MHD modeling, a three-dimensional mesh system employed in the global MHD model, and some computational results.

  14. Efficiently Finding Trends in Macroscopic MHD Stability Using Perturbed Equilibria

    NASA Astrophysics Data System (ADS)

    Comer, K. J.; Callen, J. D.; Hegna, C. C.; Turnbull, A. D.; Cowley, S. C.

    2001-10-01

    The effects of equilibrium shaping and profiles on long wavelength ideal MHD instabilities in toroidal plasmas are traditionally studied using numerical parameter scans. Previously, we introduced a new perturbative technique to explore these dependencies: assuming small equilibrium variations, new stability properties are found using a perturbation of the energy principle rather than with a traditional stability code. With this approach, stability dependencies can be efficiently examined without numerically generating complete MHD stability results for every set of parameters (which can be time-intensive for accurate representations of several configurations). Here, we briefly expand on previous successful perturbed stability analyses for screw pinch equilibria by discussing cases where the approach fails. Next, we extend the approach to toroidal geometry using the GATO and TOQ codes, and present cases that both validate the approach and suggest caution in its application.

  15. Feasibility of MHD submarine propulsion

    SciTech Connect

    Doss, E.D. ); Sikes, W.C. )

    1992-09-01

    This report describes the work performed during Phase 1 and Phase 2 of the collaborative research program established between Argonne National Laboratory (ANL) and Newport News Shipbuilding and Dry Dock Company (NNS). Phase I of the program focused on the development of computer models for Magnetohydrodynamic (MHD) propulsion. Phase 2 focused on the experimental validation of the thruster performance models and the identification, through testing, of any phenomena which may impact the attractiveness of this propulsion system for shipboard applications. The report discusses in detail the work performed in Phase 2 of the program. In Phase 2, a two Tesla test facility was designed, built, and operated. The facility test loop, its components, and their design are presented. The test matrix and its rationale are discussed. Representative experimental results of the test program are presented, and are compared to computer model predictions. In general, the results of the tests and their comparison with the predictions indicate that thephenomena affecting the performance of MHD seawater thrusters are well understood and can be accurately predicted with the developed thruster computer models.

  16. Conceptual design of a coal-fired MHD retrofit. Final technical report

    SciTech Connect

    1994-06-01

    Coal-fired magnetohydrodynamics (MHD) technology is ready for its next level of development - an integrated demonstration at a commercial scale. The development and testing of MHD has shown its potential to be the most efficient, least costly, and cleanest way to burn coal. Test results have verified a greater than 99% removal of sulphur with a potential for greater than 60% efficiency. This development and testing, primarily funded by the U.S. Department of Energy (DOE), has progressed through the completion of its proof-of-concept (POC) phase at the 50 MWt Component Development and Integration Facility (CDIF) and 28 MWt Coal Fired Flow Facility (CFFF), thereby, providing the basis for demonstration and further commercial development and application of the technology. The conceptual design of a retrofit coal-fired MHD generating plant was originally completed by the MHD Development Corporation (MDC) under this Contract, DE-AC22-87PC79669. Thereafter, this concept was updated and changed to a stand-alone MHD demonstration facility and submitted by MDC to DOE in response to the fifth round of solicitations for Clean Coal Technology. Although not selected, that activity represents the major interest in commercialization by the developing industry and the type of demonstration that would be eventually necessary. This report updates the original executive summary of the conceptual design by incorporating the results of the POC program as well as MDC`s proposed Billings MHD Demonstration Project (BMDP) and outlines the steps necessary for commercialization.

  17. Chapter 3: MHD stability, operational limits and disruptions

    NASA Astrophysics Data System (ADS)

    Hender, T. C.; Wesley, J. C.; Bialek, J.; Bondeson, A.; Boozer, A. H.; Buttery, R. J.; Garofalo, A.; Goodman, T. P.; Granetz, R. S.; Gribov, Y.; Gruber, O.; Gryaznevich, M.; Giruzzi, G.; Günter, S.; Hayashi, N.; Helander, P.; Hegna, C. C.; Howell, D. F.; Humphreys, D. A.; Huysmans, G. T. A.; Hyatt, A. W.; Isayama, A.; Jardin, S. C.; Kawano, Y.; Kellman, A.; Kessel, C.; Koslowski, H. R.; La Haye, R. J.; Lazzaro, E.; Liu, Y. Q.; Lukash, V.; Manickam, J.; Medvedev, S.; Mertens, V.; Mirnov, S. V.; Nakamura, Y.; Navratil, G.; Okabayashi, M.; Ozeki, T.; Paccagnella, R.; Pautasso, G.; Porcelli, F.; Pustovitov, V. D.; Riccardo, V.; Sato, M.; Sauter, O.; Schaffer, M. J.; Shimada, M.; Sonato, P.; Strait, E. J.; Sugihara, M.; Takechi, M.; Turnbull, A. D.; Westerhof, E.; Whyte, D. G.; Yoshino, R.; Zohm, H.; ITPA MHD, the; Disruption; Magnetic Control Topical Group

    2007-06-01

    Progress in the area of MHD stability and disruptions, since the publication of the 1999 ITER Physics Basis document (1999 Nucl. Fusion 39 2137-2664), is reviewed. Recent theoretical and experimental research has made important advances in both understanding and control of MHD stability in tokamak plasmas. Sawteeth are anticipated in the ITER baseline ELMy H-mode scenario, but the tools exist to avoid or control them through localized current drive or fast ion generation. Active control of other MHD instabilities will most likely be also required in ITER. Extrapolation from existing experiments indicates that stabilization of neoclassical tearing modes by highly localized feedback-controlled current drive should be possible in ITER. Resistive wall modes are a key issue for advanced scenarios, but again, existing experiments indicate that these modes can be stabilized by a combination of plasma rotation and direct feedback control with non-axisymmetric coils. Reduction of error fields is a requirement for avoiding non-rotating magnetic island formation and for maintaining plasma rotation to help stabilize resistive wall modes. Recent experiments have shown the feasibility of reducing error fields to an acceptable level by means of non-axisymmetric coils, possibly controlled by feedback. The MHD stability limits associated with advanced scenarios are becoming well understood theoretically, and can be extended by tailoring of the pressure and current density profiles as well as by other techniques mentioned here. There have been significant advances also in the control of disruptions, most notably by injection of massive quantities of gas, leading to reduced halo current fractions and a larger fraction of the total thermal and magnetic energy dissipated by radiation. These advances in disruption control are supported by the development of means to predict impending disruption, most notably using neural networks. In addition to these advances in means to control or

  18. Intelsat VII communications capabilities and performance

    NASA Astrophysics Data System (ADS)

    Abdel-Nabi, T.; Koh, E.; Kennedy, D.

    This paper describes the general characteristics of the Intelsat VII communications payload and analyzes the suitability of its design for digital transmission, for efficient incorporation of small earth stations into the Intelsat network, and for a relatively straightforward transition from the current Intelsat VA/VI configuration. An overview is presented of the comunications performance of the Intelsat VII satellite for the more important Intelsat digital and analog services, and earth stations standards. Specifically, the advantages, in terms of performance and capabilities, of the improved transponder linearity characteristics associated with the C-Band SSPA's and the K(u)-Band linearized TWTA's are addressed. The enhanced ability of this spacecraft to provide bandwidth where required from several possible orbital locations is discussed.

  19. CASMO5 JENDL-4.0 and ENDF/B-VII.1beta4 libraries

    SciTech Connect

    Rhodes, J.; Gheorghiu, N.; Ferrer, R.

    2012-07-01

    This paper details the generation of neutron data libraries for the CASMO5 lattice physics code based on the recently released JENDL-4.0 and ENDF/B-VII.1beta4 nuclear data evaluations. This data represents state-of-the-art nuclear data for late-2011. The key features of the new evaluations are briefly described along with the procedure for processing of this data into CASMO5, 586-energy group neutron data libraries. Finally some CASMO5 results for standard UO{sub 2} and MOX critical experiments for the two new libraries and the current ENDF/B-VII.0 CASMO5 library are presented including the B and W 1810 series, DIMPLE S06A, S06B, TCA reflector criticals with iron plates and the PNL-30-35 MOX criticals. The results show that CASMO5 with the new libraries is performing well for these criticals with a very slight edge in results to the JENDL-4.0 nuclear data evaluation over the ENDF/B-VII.1beta4 evaluation. Work is currently underway to generate a CASMO5 library based on the final ENDF/B-VII.R1 evaluation released Dec. 22, 2011. (authors)

  20. Magnetic flux ropes in 3-dimensional MHD simulations

    NASA Technical Reports Server (NTRS)

    Ogino, Tatsuki; Walker, Raymond J.; Ashour-Abdalla, Maha

    1990-01-01

    The interaction of the solar wind and the earth's magnetosphere is presently simulated by a 3D, time-dependent, global MHD method in order to model the magnetopause and magnetotail generation of magnetic flux ropes. It is noted that strongly twisted and localized magnetic flux tubes simular to magnetic flux ropes appear at the subpolar magnetopause when the IMF has a large azimuthal component, as well as a southward component. Plasmoids are generated in the magnetotail after the formation of a near-earth magnetic neutral line; the magnetic field lines have a helical structure that is connected from dawn to dusk.

  1. Clinical response to persistent, low-level beta-glucuronidase expression in the murine model of mucopolysaccharidosis type VII.

    PubMed

    Donsante, A; Levy, B; Vogler, C; Sands, M S

    2007-04-01

    Mucopolysaccharidosis type VII (MPS VII) is a lysosomal storage disease caused by beta-glucuronidase (GUSB) deficiency. This disease exhibits a broad spectrum of clinical signs including skeletal dysplasia, retinal degeneration, cognitive deficits and hearing impairment. Sustained, high-level expression of GUSB significantly improves the clinical course of the disease in the murine model of MPS VII. Low levels of enzyme expression (1-5% of normal) can significantly reduce the biochemical and histopathological manifestations of MPS VII. However, it has not been clear from previous studies whether persistent, low levels of circulating GUSB lead to significant improvements in the clinical presentation of this disease. We generated a rAAV2 vector that mediates persistent, low-level GUSB expression in the liver. Liver and serum levels of GUSB were maintained at approximately 5% and approximately 2.5% of normal, respectively, while other tissue ranged from background levels to 0.9%. This level of activity significantly reduced the secondary elevations of alpha-galactosidase and the levels of glycosaminoglycans in multiple tissues. Interestingly, this level of GUSB was also sufficient to reduce lysosomal storage in neurons in the brain. Although there were small but statistically significant improvements in retinal function, auditory function, skeletal dysplasia, and reproduction in rAAV-treated MPS VII mice, the clinical deficits were still profound and there was no improvement in lifespan. These data suggest that circulating levels of GUSB greater than 2.5% will be required to achieve substantial clinical improvements in MPS VII.

  2. MHD Technology Transfer, Integration and Review Committee

    SciTech Connect

    Not Available

    1989-10-01

    As part of the MHD Integrated Topping Cycle (ITC) project, TRW was given the responsibility to organize, charter and co-chair, with the Department of Energy (DOE), an MHD Technology Transfer, Integration and Review Committee (TTIRC). The Charter of the TTIRC, which was approved by the DOE in June 1988 and distributed to the committee members, is included as part of this Summary. As stated in the Charter, the purpose of this committee is to: (1) review all Proof-of-Concept (POC) projects and schedules in the national MHD program; to assess their compatibility with each other and the first commercial MHD retrofit plant; (2) establish and implement technology transfer formats for users of this technology; (3) identify interfaces, issues, and funding structures directly impacting the success of the commercial retrofit; (4) investigate and identify the manner in which, and by whom, the above should be resolved; and (5) investigate and assess other participation (foreign and domestic) in the US MHD Program. The DOE fiscal year 1989 MHD Program Plan Schedule is included at the end of this Summary. The MHD Technology Transfer, Integration and Review Committee's activities to date have focused primarily on the technology transfer'' aspects of its charter. It has provided a forum for the dissemination of technical and programmatic information among workers in the field of MHD and to the potential end users, the utilities, by holding semi-annual meetings. The committee publishes this semi-annual report, which presents in Sections 2 through 11 capsule summaries of technical progress for all DOE Proof-of-Concept MHD contracts and major test facilities.

  3. Parametric analysis of closed cycle magnetohydrodynamic (MHD) power plants

    NASA Technical Reports Server (NTRS)

    Owens, W.; Berg, R.; Murthy, R.; Patten, J.

    1981-01-01

    A parametric analysis of closed cycle MHD power plants was performed which studied the technical feasibility, associated capital cost, and cost of electricity for the direct combustion of coal or coal derived fuel. Three reference plants, differing primarily in the method of coal conversion utilized, were defined. Reference Plant 1 used direct coal fired combustion while Reference Plants 2 and 3 employed on site integrated gasifiers. Reference Plant 2 used a pressurized gasifier while Reference Plant 3 used a ""state of the art' atmospheric gasifier. Thirty plant configurations were considered by using parametric variations from the Reference Plants. Parametric variations include the type of coal (Montana Rosebud or Illinois No. 6), clean up systems (hot or cold gas clean up), on or two stage atmospheric or pressurized direct fired coal combustors, and six different gasifier systems. Plant sizes ranged from 100 to 1000 MWe. Overall plant performance was calculated using two methodologies. In one task, the channel performance was assumed and the MHD topping cycle efficiencies were based on the assumed values. A second task involved rigorous calculations of channel performance (enthalpy extraction, isentropic efficiency and generator output) that verified the original (task one) assumptions. Closed cycle MHD capital costs were estimated for the task one plants; task two cost estimates were made for the channel and magnet only.

  4. MHD Integrated Topping Cycle Project

    SciTech Connect

    Not Available

    1992-07-01

    This seventeenth quarterly technical progress report of the MHD Integrated Topping Cycle Project presents the accomplishments during the period August 1, 1991 to October 31, 1991. Manufacturing of the prototypical combustor pressure shell has been completed including leak, proof, and assembly fit checking. Manufacturing of forty-five cooling panels was also completed including leak, proof, and flow testing. All precombustor internal components (combustion can baffle and swirl box) were received and checked, and integration of the components was initiated. A decision was made regarding the primary and backup designs for the 1A4 channel. The assembly of the channel related prototypical hardware continued. The cathode wall electrical wiring is now complete. The mechanical design of the diffuser has been completed.

  5. Cosmological AMR MHD with Enzo

    SciTech Connect

    Xu, Hao; Li, Hui; Li, Shengtai

    2009-01-01

    In this work, we present EnzoMHD, the extension of the cosmological code Enzoto include magnetic fields. We use the hyperbolic solver of Li et al. (2008) for the computation of interface fluxes. We use constrained transport methods of Balsara & Spicer (1999) and Gardiner & Stone (2005) to advance the induction equation, the reconstruction technique of Balsara (2001) to extend the Adaptive Mesh Refinement of Berger & Colella (1989) already used in Enzo, though formulated in a slightly different way for ease of implementation. This combination of methods preserves the divergence of the magnetic field to machine precision. We use operator splitting to include gravity and cosmological expansion. We then present a series of cosmological and non cosmologjcal tests problems to demonstrate the quality of solution resulting from this combination of solvers.

  6. Extended MHD Modeling of Tearing-Driven Magnetic Relaxation

    NASA Astrophysics Data System (ADS)

    Sauppe, Joshua

    2016-10-01

    Driven plasma pinch configurations are characterized by the gradual accumulation and episodic release of free energy in discrete relaxation events. The hallmark of this relaxation in a reversed-field pinch (RFP) plasma is flattening of the parallel current density profile effected by a fluctuation-induced dynamo emf in Ohm's law. Nonlinear two-fluid modeling of macroscopic RFP dynamics has shown appreciable coupling of magnetic relaxation and the evolution of plasma flow. Accurate modeling of RFP dynamics requires the Hall effect in Ohm's law as well as first order ion finite Larmor radius (FLR) effects, represented by the Braginskii ion gyroviscous stress tensor. New results find that the Hall dynamo effect from < J × B > / ne can counter the MHD effect from - < V × B > in some of the relaxation events. The MHD effect dominates these events and relaxes the current profile toward the Taylor state, but the opposition of the two dynamos generates plasma flow in the direction of equilibrium current density, consistent with experimental measurements. Detailed experimental measurements of the MHD and Hall emf terms are compared to these extended MHD predictions. Tracking the evolution of magnetic energy, helicity, and hybrid helicity during relaxation identifies the most important contributions in single-fluid and two-fluid models. Magnetic helicity is well conserved relative to the magnetic energy during relaxation. The hybrid helicity is dominated by magnetic helicity in realistic low-beta pinch conditions and is also well conserved. Differences of less than 1 % between magnetic helicity and hybrid helicity are observed with two-fluid modeling and result from cross helicity evolution through ion FLR effects, which have not been included in contemporary relaxation theories. The kinetic energy driven by relaxation in the computations is dominated by velocity components perpendicular to the magnetic field, an effect that had not been predicted. Work performed at

  7. Pulse Detonation Rocket MHD Power Experiment

    NASA Technical Reports Server (NTRS)

    Litchford, Ron J.; Cook, Stephen (Technical Monitor)

    2002-01-01

    A pulse detonation research engine (MSFC (Marshall Space Flight Center) Model PDRE (Pulse Detonation Rocket Engine) G-2) has been developed for the purpose of examining integrated propulsion and magnetohydrodynamic power generation applications. The engine is based on a rectangular cross-section tube coupled to a converging-diverging nozzle, which is in turn attached to a segmented Faraday channel. As part of the shakedown testing activity, the pressure wave was interrogated along the length of the engine while running on hydrogen/oxygen propellants. Rapid transition to detonation wave propagation was insured through the use of a short Schelkin spiral near the head of the engine. The measured detonation wave velocities were in excess of 2500 m/s in agreement with the theoretical C-J velocity. The engine was first tested in a straight tube configuration without a nozzle, and the time resolved thrust was measured simultaneously with the head-end pressure. Similar measurements were made with the converging-diverging nozzle attached. The time correlation of the thrust and head-end pressure data was found to be excellent. The major purpose of the converging-diverging nozzle was to configure the engine for driving an MHD generator for the direct production of electrical power. Additional tests were therefore necessary in which seed (cesium-hydroxide dissolved in methanol) was directly injected into the engine as a spray. The exhaust plume was then interrogated with a microwave interferometer in an attempt to characterize the plasma conditions, and emission spectroscopy measurements were also acquired. Data reduction efforts indicate that the plasma exhaust is very highly ionized, although there is some uncertainty at this time as to the relative abundance of negative OH ions. The emission spectroscopy data provided some indication of the species in the exhaust as well as a measurement of temperature. A 24-electrode-pair segmented Faraday channel and 0.6 Tesla permanent

  8. MHD Integrated Topping Cycle Project

    SciTech Connect

    Not Available

    1992-02-01

    A summary of the work is excerpted here. Final design of an MHD channel for the ITC program POC test has been completed. The channel was designed to be capable of 1.5 MW {sub e} power output and a lifetime of 2000 hours. Emphasis was placed upon durability and reliability. Hence, specific measures were taken to design against channel damage due to electric faults. The life-limiting issues associated with electrochemical corrosion and erosion of gas-side surfaces were addressed by the use of various materials with proven wear characteristics in a coal-fired MHD channel environment. Pitting of prototypical sidewall coupons was observed in the CDIF workhorse testing. The most likely cause of the observed pitting, water leaks resulting from cooling water tube braze failures, has been remedied. New brazing procedures and isolation of the sidebar gas-side material from water contact will prevent sidebar pitting in the prototypical channel. Water-side corrosion tests reported in this quarterly report include the latest results of tungsten-copper elements at controlled pH, heat flux and voltage levels. In the combustion subsystem, efforts continued to focus on understanding and improving the current levels of slag recovery and seed utilization achieved by the combustor. Analytical support was also provided in the areas of slag rejection system operation, precombustor operation, and oil burner design modification. Channel data analysis activities continued in support of prototypical coupon testing at the CDIF. Analyses are presented on channel wall slagging behavior and sidewall voltage distributions.

  9. ENDF/B-VII.1 versus ENDF/B-VII.0: What's Different?

    SciTech Connect

    Cullen, D E

    2012-03-20

    Recently the new ENDF/B-VII.1 library was released; this completely replaces the earlier ENDF/B-VII.0 library. One of the first questions we ask about a new library is: What's Different? Here I attempt to at least partially answer this question. I present results in both tabulated form (so you can quickly determine if any evaluations of interest to you have changed), and graphic form (so that you can see how much evaluations have changed and in what energy ranges). For the table I have compared what I refer to as the ENDF neutron data, namely MF=1 through 6. Here I did a character-by-character comparison of the same sections (MF/MT) that appear I both ENDF/B-VII.0 and VII.1; here I found differences in 170 evaluations. For the plots I have only compared the total cross sections for all evaluations that are common to both libraries, and I found that of the 423 evaluations in ENDF/B-VII.1, 120 of these have total cross sections that differ by 1% or more from the evaluation of the same isotope in ENDF/B-VII.0. This should be considered only a preliminary comparison; obviously there can be more subtle important differences that do not effect of total cross sections. Here I present plots comparing the total cross section of these 120 isotopes. The plots are only broad overviews of the total cross sections over their entire energy range. If you have interest in more detailed plots for specific evaluations, you can download the evaluations [1,2] and the PREPRO [3] codes I used to prepare and view the data. This is all I needed to do my comparisons, and is all you should need to do any more detailed comparisons to meet your individual needs.

  10. Novel and potent anti-tumor and anti-metastatic di-2-pyridylketone thiosemicarbazones demonstrate marked differences in pharmacology between the first and second generation lead agents

    PubMed Central

    Sestak, Vit; Stariat, Jan; Cermanova, Jolana; Potuckova, Eliska; Chladek, Jaroslav; Roh, Jaroslav; Bures, Jan; Jansova, Hana; Prusa, Petr; Sterba, Martin; Micuda, Stanislav; Simunek, Tomas; Kalinowski, Danuta S.; Richardson, Des R.; Kovarikova, Petra

    2015-01-01

    Di(2-pyridyl)ketone 4,4-dimethyl-3-thiosemicarbazone (Dp44mT) and di(2-pyridyl)ketone 4-cyclohexyl-4-methyl-3-thiosemicarbazone (DpC) are novel, highly potent and selective anti-tumor and anti-metastatic drugs. Despite their structural similarity, these agents differ in their efficacy and toxicity in-vivo. Considering this, a comparison of their pharmacokinetic and pharmaco/toxico-dynamic properties was conducted to reveal if these factors are involved in their differential activity. Both compounds were administered to Wistar rats intravenously (2 mg/kg) and their metabolism and disposition were studied using UHPLC-MS/MS. The cytotoxicity of both thiosemicarbazones and their metabolites was also examined using MCF-7, HL-60 and HCT116 tumor cells and 3T3 fibroblasts and H9c2 cardiac myoblasts. Their intracellular iron-binding ability was characterized by the Calcein-AM assay and their iron mobilization efficacy was evaluated. In contrast to DpC, Dp44mT undergoes rapid demethylation in-vivo, which may be related to its markedly faster elimination (T1/2 = 1.7 h for Dp44mT vs. 10.7 h for DpC) and lower exposure. Incubation of these compounds with cancer cells or cardiac myoblasts did not result in any significant metabolism in-vitro. The metabolism of Dp44mT in-vivo resulted in decreased anti-cancer activity and toxicity. In conclusion, marked differences in the pharmacology of Dp44mT and DpC were observed and highlight the favorable pharmacokinetics of DpC for cancer treatment. PMID:26623727

  11. Open Boundary Conditions for Dissipative MHD

    SciTech Connect

    Meier, E T

    2011-11-10

    In modeling magnetic confinement, astrophysics, and plasma propulsion, representing the entire physical domain is often difficult or impossible, and artificial, or 'open' boundaries are appropriate. A novel open boundary condition (BC) for dissipative MHD, called Lacuna-based open BC (LOBC), is presented. LOBC, based on the idea of lacuna-based truncation originally presented by V.S. Ryaben'kii and S.V. Tsynkov, provide truncation with low numerical noise and minimal reflections. For hyperbolic systems, characteristic-based BC (CBC) exist for separating the solution into outgoing and incoming parts. In the hyperbolic-parabolic dissipative MHD system, such separation is not possible, and CBC are numerically unstable. LOBC are applied in dissipative MHD test problems including a translating FRC, and coaxial-electrode plasma acceleration. Solution quality is compared to solutions using CBC and zero-normal derivative BC. LOBC are a promising new open BC option for dissipative MHD.

  12. Magnetohydrodynamic generator of electrical energy using gasification products of lignite coal

    NASA Astrophysics Data System (ADS)

    Derevianko, V. A.; Slavin, V. S.; Sokolov, V. S.

    1980-10-01

    An investigation is presented of an MHD generator of electrical energy fueled by gasification products of lignite coals using the T-layer effect which eliminates caustic additives. A quasi-one-dimensional theory of linear MHD processes is constructed on the basis of MHD equations; a design of an industrial generator is discussed.

  13. Applying MHD Results to a Scramjet Vehicle

    DTIC Science & Technology

    2007-02-12

    1194, Reno, NV, January 2005. 10. Rosa, R.J., "Magnetohydrodynamic Energy Conversion", Hemisphere Publishing Corp., New York, 1968, Revised Printing ...Introduction and Background Projects Analytical and experimental studies of both electrohydrodynamic (EHD) and magnetohydrodynamic (MHD) application to...Institute, Tullahoma, TN, June 1981. 26. Vendell, E.W., "Free- Jet Electrical Conductivity Profiles of a Seeded MHD Combustion Plasma", 15"’ Symposium

  14. MHD Instabilities in Simple Plasma Configuration

    DTIC Science & Technology

    1984-01-01

    cause the field lines to break and reconnect. . This work is divided into two parts. Chapters " describe linear theory and Chapters -XV- describe the...details in any non- linear theory can rapidly mushroom out of all proportion. For this reason much work in nonlinear MHD theory is done by numerical...99 IX. INSTABILITIES IN A TOROIDAL PLASMA ........................ 125 X. QUASI- LINEAR THEORY OF MHD INSTABILITIES ........... 133

  15. The Biermann Catastrophe in Numerical MHD

    NASA Astrophysics Data System (ADS)

    Graziani, Carlo; Tzeferacos, Petros; Lee, Dongwook; Weide, Klaus; Lamb, Donald; Fatenejad, Milad; Miller, Joshua

    2014-10-01

    The Biermann Battery (BB) effect is widely invoked as a mechanism to generate cosmic magnetic fields from unmagnetized plasmas. The BB effect, which relies on large, non-aligned gradients of electron density and pressure, is expected to function most efficiently at shocks, where such gradients are largest. Simulations of cosmic magnetogenesis have accordingly relied on shocks to enhance the BB effect. What went unnoticed until recently is the fact that straightforward algorithmic implementations of the BB effect in MHD codes break down precisely at hydrodynamic discontinuities such as shocks - where the BB effect is of greatest interest - yielding results that fail to converge with resolution. We discuss this breakdown, show its origin, and present an alternative algorithm that gives finite and convergent results. We demonstrate convergence using an implementation of the algorithm within the FLASH code, and verify that the algorithm yields physically sensible results at shocks. We discuss novel - and physically observable - effects that attend the BB effect at shocks. This work was supported in part at the University of Chicago by DOE NNSA ASC.

  16. Decreased MCM2-6 in Drosophila S2 Cells Does Not Generate Significant DNA Damage or Cause a Marked Increase in Sensitivity to Replication Interference

    PubMed Central

    Crevel, Isabelle; Crevel, Gilles; Gostan, Thierry; de Renty, Christelle; Coulon, Vincent; Cotterill, Sue

    2011-01-01

    A reduction in the level of some MCM proteins in human cancer cells (MCM5 in U20S cells or MCM3 in Hela cells) causes a rapid increase in the level of DNA damage under normal conditions of cell proliferation and a loss of viability when the cells are subjected to replication interference. Here we show that Drosophila S2 cells do not appear to show the same degree of sensitivity to MCM2-6 reduction. Under normal cell growth conditions a reduction of >95% in the levels of MCM3, 5, and 6 causes no significant short term alteration in the parameters of DNA replication or increase in DNA damage. MCM depleted cells challenged with HU do show a decrease in the density of replication forks compared to cells with normal levels of MCM proteins, but this produces no consistent change in the levels of DNA damage observed. In contrast a comparable reduction of MCM7 levels has marked effects on viability, replication parameters and DNA damage in the absence of HU treatment. PMID:22102875

  17. The Next Generation Virgo Cluster Survey. VII. The Intrinsic Shapes of Low-luminosity Galaxies in the Core of the Virgo Cluster, and a Comparison with the Local Group

    NASA Astrophysics Data System (ADS)

    Sánchez-Janssen, Rubén; Ferrarese, Laura; MacArthur, Lauren A.; Côté, Patrick; Blakeslee, John P.; Cuillandre, Jean-Charles; Duc, Pierre-Alain; Durrell, Patrick; Gwyn, Stephen; McConnacchie, Alan W.; Boselli, Alessandro; Courteau, Stéphane; Emsellem, Eric; Mei, Simona; Peng, Eric; Puzia, Thomas H.; Roediger, Joel; Simard, Luc; Boyer, Fred; Santos, Matthew

    2016-03-01

    We investigate the intrinsic shapes of low-luminosity galaxies in the central 300 kpc of the Virgo Cluster using deep imaging obtained as part of the Next Generation Virgo Cluster Survey (NGVS). We build a sample of nearly 300 red-sequence cluster members in the yet-unexplored -14 < Mg < -8 mag range, and we measure their apparent axis ratios, q, through Sérsic fits to their two-dimensional light distribution, which is well described by a constant ellipticity parameter. The resulting distribution of apparent axis ratios is then fit by families of triaxial models with normally distributed intrinsic ellipticities, E = 1 - C/A, and triaxialities, T = (A2 - B2)/(A2 - C2). We develop a Bayesian framework to explore the posterior distribution of the model parameters, which allows us to work directly on discrete data, and to account for individual, surface-brightness-dependent axis ratio uncertainties. For this population we infer a mean intrinsic ellipticity \\bar{E} = {0.43}-0.02+0.02 and a mean triaxiality \\bar{T} = {0.16}-0.06+0.07. This implies that faint Virgo galaxies are best described as a family of thick, nearly oblate spheroids with mean intrinsic axis ratios 1:0.94:0.57. The core of Virgo lacks highly elongated low-luminosity galaxies, with 95% of the population having q > 0.45. We additionally attempt a study of the intrinsic shapes of Local Group (LG) satellites of similar luminosities. For the LG population we infer a slightly larger mean intrinsic ellipticity \\bar{E} = {0.51}-0.06+0.07, and the paucity of objects with round apparent shapes translates into more triaxial mean shapes, 1:0.76:0.49. Numerical studies that follow the tidal evolution of satellites within LG-sized halos are in good agreement with the inferred shape distributions, but the mismatch for faint galaxies in Virgo highlights the need for more adequate simulations of this population in the cluster environment. We finally compare the intrinsic shapes of NGVS low-mass galaxies with

  18. Marking nut anaphylaxis

    PubMed Central

    Kral, Anita Christine; Hayball, John; Smith, William B

    2016-01-01

    Marking nut Semecarpus anacardium, so-called because it contains a pigment that has been used in the past to mark fabrics, is a known cause of contact hypersensitivity. It may be ingested as an ingredient of some traditional Hindi foods. We describe the first reported case of anaphylaxis to marking nut. PMID:27489793

  19. Anisotropy of MHD Turbulence at Low Magnetic Reynolds Number

    NASA Technical Reports Server (NTRS)

    Zikanov, O.; Vorobev, A.; Thess, A.; Davidson, P. A.; Knaepen, B.

    2004-01-01

    Turbulent fluctuations in MHD flows are known to become dimensionally anisotropic under the action of a sufficiently strong magnetic field. We consider the technologically relevant case of low magnetic Reynolds number and apply the method of DNS of forced flow in a periodic box to generate velocity fields. The analysis based on different anisotropy characteristics shows that the dimensional anisotropy is virtually scale-independent. We also find that, except for the case of very strong magnetic field, the flow is componentally isotropic. Its kinetic energy is practically uniformly distributed among the velocity components.

  20. MHD equilibria with diamagnetic effects

    NASA Astrophysics Data System (ADS)

    Tessarotto, M.; Zorat, R.; Johnson, J. L.; White, R. B.

    1997-11-01

    An outstanding issue in magnetic confinement is the establishment of MHD equilibria with enhanced flow shear profiles for which turbulence (and transport) may be locally effectively suppressed or at least substantially reduced with respect to standard weak turbulence models. Strong flows develop in the presence of equilibrium E× B-drifts produced by a strong radial electric field, as well as due to diamagnetic contributions produced by steep equilibrium radial profiles of number density, temperature and the flow velocity itself. In the framework of a kinetic description, this generally requires the construction of guiding-center variables correct to second order in the relevant expansion parameter. For this purpose, the Lagrangian approach developed recently by Tessarotto et al. [1] is adopted. In this paper the conditions of existence of such equilibria are analyzed and their basic physical properties are investigated in detail. 1 - M. Pozzo, M. Tessarotto and R. Zorat, in Theory of fusion Plasmas, E.Sindoni et al. eds. (Societá Italiana di Fisica, Editrice Compositori, Bologna, 1996), p.295.

  1. MHD Integrated Topping Cycle Project

    SciTech Connect

    Not Available

    1992-02-01

    This fourteenth quarterly technical progress report of the MHD Integrated Topping Cycle Project presents the accomplishments during the period November 1, 1990 to January 31, 1991. Testing of the High Pressure Cooling Subsystem electrical isolator was completed. The PEEK material successfully passed the high temperature, high pressure duration tests (50 hours). The Combustion Subsystem drawings were CADAM released. The procurement process is in progress. An equipment specification and RFP were prepared for the new Low Pressure Cooling System (LPCS) and released for quotation. Work has been conducted on confirmation tests leading to final gas-side designs and studies to assist in channel fabrication.The final cathode gas-side design and the proposed gas-side designs of the anode and sidewall are presented. Anode confirmation tests and related analyses of anode wear mechanisms used in the selection of the proposed anode design are presented. Sidewall confirmation tests, which were used to select the proposed gas-side design, were conducted. The design for the full scale CDIF system was completed. A test program was initiated to investigate the practicality of using Avco current controls for current consolidation in the power takeoff (PTO) regions and to determine the cause of past current consolidation failures. Another important activity was the installation of 1A4-style coupons in the 1A1 channel. A description of the coupons and their location with 1A1 channel is presented herein.

  2. MHD waveguides in space plasma

    SciTech Connect

    Mazur, N. G.; Fedorov, E. N.; Pilipenko, V. A.

    2010-07-15

    The waveguide properties of two characteristic formations in the Earth's magnetotail-the plasma sheet and the current (neutral) sheet-are considered. The question of how the domains of existence of different types of MHD waveguide modes (fast and slow, body and surface) in the (k, {omega}) plane and their dispersion properties depend on the waveguide parameters is studied. Investigation of the dispersion relation in a number of particular (limiting) cases makes it possible to obtain a fairly complete qualitative pattern of all the branches of the dispersion curve. Accounting for the finite size of perturbations across the wave propagation direction reveals new additional effects such as a change in the critical waveguide frequencies, the excitation of longitudinal current at the boundaries of the sheets, and a change in the symmetry of the fundamental mode. Knowledge of the waveguide properties of the plasma and current sheets can explain the occurrence of preferred frequencies in the low-frequency fluctuation spectra in the magnetotail. In satellite observations, the type of waveguide mode can be determined from the spectral properties, as well as from the phase relationships between plasma oscillations and magnetic field oscillations that are presented in this paper.

  3. Molecular analysis of patients with beta-glucuronidase deficiency presenting as hydrops fetalis or as early mucopolysaccharidosis VII.

    PubMed

    Vervoort, R; Islam, M R; Sly, W S; Zabot, M T; Kleijer, W J; Chabas, A; Fensom, A; Young, E P; Liebaers, I; Lissens, W

    1996-03-01

    Although not all mucopolysaccharidosis type VII (MPS VII) neonates present with hydrops fetalis or with related symptoms, hydrops fetalis is a common form of presentation of this mucopolysaccharidosis. We used reverse-transcription-PCR-SSCP and direct sequencing to screen for mutations in the human beta-glucuronidase cDNA of 17 MPS VII patients with severe presentation of the disease. Mutations resulting in an unstable mRNA were detected in genomic DNA with direct sequencing of the PCR-amplified beta-glucuronidase exons. We found extensive genetic heterogeneity in MPS VII alleles: in addition to 6 or 12 previously reported mutations (L176F, R216W, R357X, R382C, W507X, and W627C), we detected 14 undescribed mutations in the beta-glucuronidase coding region that produce MPS VII alleles (G136R, E150K, S312X, Y320S, Y320C, H351Y, R382H, R374C, R435P, R477W, G572D, Y508C, K606N and 1900 delta GA). The mutations in hydropic fetuses were widely scattered in the beta-glucuronidase gene. Analysis of three polymorphic sites of the mutant alleles (1766T/C, 1972C/T and a new 1091+27C/G polymorphism) allowed exclusion of identity by descent for some recurrent mutations. Three of four mutations introducing a premature translation stop codon were found to affect mRNA abundance and/or structure. Expression studies provided evidence for the causal relationship between each of the mutations found in MPS VII alleles and the enzyme deficiency, in that all mutations identified exhibited markedly reduced enzyme activity expressed in COS7 cells following transfection with the mutant cDNA.

  4. Molecular analysis of patients with beta-glucuronidase deficiency presenting as hydrops fetalis or as early mucopolysaccharidosis VII.

    PubMed Central

    Vervoort, R.; Islam, M. R.; Sly, W. S.; Zabot, M. T.; Kleijer, W. J.; Chabas, A.; Fensom, A.; Young, E. P.; Liebaers, I.; Lissens, W.

    1996-01-01

    Although not all mucopolysaccharidosis type VII (MPS VII) neonates present with hydrops fetalis or with related symptoms, hydrops fetalis is a common form of presentation of this mucopolysaccharidosis. We used reverse-transcription-PCR-SSCP and direct sequencing to screen for mutations in the human beta-glucuronidase cDNA of 17 MPS VII patients with severe presentation of the disease. Mutations resulting in an unstable mRNA were detected in genomic DNA with direct sequencing of the PCR-amplified beta-glucuronidase exons. We found extensive genetic heterogeneity in MPS VII alleles: in addition to 6 or 12 previously reported mutations (L176F, R216W, R357X, R382C, W507X, and W627C), we detected 14 undescribed mutations in the beta-glucuronidase coding region that produce MPS VII alleles (G136R, E150K, S312X, Y320S, Y320C, H351Y, R382H, R374C, R435P, R477W, G572D, Y508C, K606N and 1900 delta GA). The mutations in hydropic fetuses were widely scattered in the beta-glucuronidase gene. Analysis of three polymorphic sites of the mutant alleles (1766T/C, 1972C/T and a new 1091+27C/G polymorphism) allowed exclusion of identity by descent for some recurrent mutations. Three of four mutations introducing a premature translation stop codon were found to affect mRNA abundance and/or structure. Expression studies provided evidence for the causal relationship between each of the mutations found in MPS VII alleles and the enzyme deficiency, in that all mutations identified exhibited markedly reduced enzyme activity expressed in COS7 cells following transfection with the mutant cDNA. Images Figure 2 Figure 3A Figure 3BC Figure 4 PMID:8644704

  5. 40 CFR Appendixes I-Vii to Part 85 - [Reserved

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 19 2013-07-01 2013-07-01 false I Appendixes I-VII to Part 85 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONTROL OF AIR POLLUTION FROM MOBILE SOURCES Appendixes I-VII to Part 85...

  6. 40 CFR Appendixes I-Vii to Part 85 - [Reserved

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 18 2011-07-01 2011-07-01 false I Appendixes I-VII to Part 85 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONTROL OF AIR POLLUTION FROM MOBILE SOURCES Appendixes I-VII to Part 85...

  7. 40 CFR Appendixes I-Vii to Part 85 - [Reserved

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 19 2014-07-01 2014-07-01 false I Appendixes I-VII to Part 85 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONTROL OF AIR POLLUTION FROM MOBILE SOURCES Appendixes I-VII to Part 85...

  8. 40 CFR Appendixes I-Vii to Part 85 - [Reserved

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 18 2010-07-01 2010-07-01 false I Appendixes I-VII to Part 85 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONTROL OF AIR POLLUTION FROM MOBILE SOURCES Appendixes I-VII to Part 85...

  9. 40 CFR Appendixes I-Vii to Part 85 - [Reserved

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 19 2012-07-01 2012-07-01 false I Appendixes I-VII to Part 85 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONTROL OF AIR POLLUTION FROM MOBILE SOURCES Appendixes I-VII to Part 85...

  10. 32 CFR 2003.7 - Support Staff (Article VII).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 32 National Defense 6 2014-07-01 2014-07-01 false Support Staff (Article VII). 2003.7 Section 2003.7 National Defense Other Regulations Relating to National Defense INFORMATION SECURITY OVERSIGHT... (ISCAP) BYLAWS, RULES, AND APPEAL PROCEDURES Bylaws § 2003.7 Support Staff (Article VII). The staff...

  11. Title VII and Public Employers: Did Congress Exceed Its Powers?

    ERIC Educational Resources Information Center

    Dean, John P.

    1979-01-01

    The impact of federal legislation aimed at discriminatory practices of state and local governments as mandated by the Civil Rights Act of 1964 and the Equal Employment Opportunity Act of 1972 is examined. Several Title VII violations are outlined; it is concluded that federal authority can be upheld under Title VII and the Fourteenth Amendment.…

  12. MHD heat and seed recovery technology project. Ninth quarterly report, January-March 1980

    SciTech Connect

    Petrick, Michael; Johnson, Terry R.

    1980-05-01

    The MHD Heat and Seed Recovery Technology Project at Argonne National Laboratory is obtaining information for the design and operation of the steam plant downstream of the MHD channel-diffuser, and of the seed regeneration process. The project goal is to supply the engineering data required in the design of components for prototype and demonstration MHD facilities. The primary effort of the HSR Technology Project at Argonne is directed toward experimental investigations of critical problem areas, such as (1) NO/sub x/ behavior in the radiant boiler and secondary combustor; (2) radiant boiler design to meet the multiple requirements of steam generation, NO/sub x/ decomposition, and seed-slag separation; (3) effects of solid or liquid seed deposits on heat transfer and gas flow in the steam and air heaters; (4) formation, growth, and deposition of seed-slag particles; and (5) character of the combustion gas effluents. These investigations are performed primarily in a 2-MW test facility, Argonne MHD Process Engineering Laboratory (AMPEL). Other project activities are related to studies of the thermochemistry of the seed-slag combustion gas system, identification of ceramic and metallic materials for service in the MHD-steam plant, and evaluation of seed regeneration processes. Progress is described.

  13. MHD heat and seed recovery technology project. Eighth quarterly report, October-December 1979

    SciTech Connect

    Petrick, M.; Johnson, T. R.

    1980-08-01

    The MHD Heat and Seed Recovery Technology Project at Argonne National Laboratory is obtaining information for the design and operation of the steam plant downstream of the MHD channel-diffuser, and of the seed regeneration process. The project goal is to supply the engineering data required in the design of components for prototype and demonstration MHD facilities. The work is being done in close cooperation with the Heat Recovery-Seed Recovery facilities, which will be 20-MW prototypes of the MHD steam bottoming system. The primary effort of the HSR Technology Project is directed toward experimental investigations of critical issues, such as (1) NO/sub x/ behavior in the radiant boiler and secondary combustor; (2) radiant boiler design to meet the multiple requirements of steam generation, NO/sub x/ decomposition, and seed-slag separation; (3) effects of solid or liquid seed deposits on heat transfer and gas flow in the steam and air heaters; (4) formation, growth, and deposition of the seed-slag particles; (5) character of the combustion gas effluents; and (6) the corrosion and erosion of ceramic and metallic materials of construction. These investigations are performed primarily in a 2-MW test facility, Argonne MHD Process Engineering Laboratory (AMPEL). Other project activities are related to studies of the thermochemistry of the seed-slag combustion gas system. Activities are reported.

  14. A numerical code for a three-dimensional magnetospheric MHD equilibrium model

    NASA Technical Reports Server (NTRS)

    Voigt, G.-H.

    1992-01-01

    Two dimensional and three dimensional MHD equilibrium models were begun for Earth's magnetosphere. The original proposal was motivated by realizing that global, purely data based models of Earth's magnetosphere are inadequate for studying the underlying plasma physical principles according to which the magnetosphere evolves on the quasi-static convection time scale. Complex numerical grid generation schemes were established for a 3-D Poisson solver, and a robust Grad-Shafranov solver was coded for high beta MHD equilibria. Thus, the effects were calculated of both the magnetopause geometry and boundary conditions on the magnetotail current distribution.

  15. MHD simulations of DC helicity injection for current drive in tokamaks

    SciTech Connect

    Sovinec, C.R.; Prager, S.C.

    1994-12-01

    MHD computations of DC helicity injection in tokamak-like configurations show current drive with no ``loop voltage`` in a resistive, pressureless plasma. The self-consistently generated current profiles are unstable to resistive modes that partially relax the profile through the MHD dynamo mechanism. The current driven by the fluctuations leads to closed contours of average poloidal flux. However, the 1% fluctuation level is large enough to produce a region of stochastic magnetic field. A limited Lundquist number (S) scan from 2.5 {times} 10{sup 3} to 4 {times} 10{sup 4} indicates that both the fluctuation level and relaxation increase with S.

  16. Advanced LMMHD space power generation concept

    NASA Astrophysics Data System (ADS)

    Ho, Vincent; Wong, Albert; Kim, Kilyoo; Dhir, Vijay

    Magnetohydrodynamic (MHD) power generation concept has been proposed and studied worldwide as one of the future power generation sources. An advanced one fluid two phase liquid metal (LM) MHD power generation concept was developed for space nuclear power generation design. The concept employs a nozzle to accelerate the liquid metal coolant to an acceptable velocity with Mach number greater than unity. Such nozzle and the MHD power generator replace the turbogenerator of a high temperature Rankine turboelectric cycle concept. As a result, the power generation system contains no movable parts. This provides high reliability, which is a very important factor in space application.

  17. a New ENDF/B-VII.0 Based Multigroup Cross-Section Library for Reactor Dosimetry

    NASA Astrophysics Data System (ADS)

    Alpan, F. A.; Anderson, S. L.

    2009-08-01

    The latest of the ENDF/B libraries, ENDF/B-VII.0 was released in December 2006. In this paper, the ENDF/B-VII.O evaluations were used in generating a new coupled neutron/gamma multigroup library having the same group structure of VITAMIN-B6, i.e., the 199-neutron, 42-gamma group library. The new library was generated utilizing NJOY99.259 for pre-processing and the AMPX modules for post-processing of cross sections. An ENDF/B-VI.3 based VITAMIN-B6-like library was also generated. The fine-group libraries and the ENDF/B-VI.3 based 47-neutron, 20-gamma group BUGLE-96 library were used with the discrete ordinates code DORT to obtain a three-dimensional synthesized flux distribution from r, r-θ, and r-z models for a standard Westinghouse 3-loop design reactor. Reaction rates were calculated for ex-vessel neutron dosimetry containing 63Cu(n,α)60Co, 46Ti(n,p)46Sc, 54Fe(n,P)54Mn, 58Ni(n,P)58Co, 238U(n,f)137Cs, 237Np(n,f)137Cs, and 59Co(n,γ)60Co (bare and cadmium covered) reactions. Results were compared to measurements. In comparing the 199-neutron, 42-gamma group ENDF/B-VI.3 and ENDF/B-VII.O libraries, it was observed that the ENDF/B-VI.3 based library results were in better agreement with measurements. There is a maximum difference of 7% (for the 63Cu(n,α)60Co reaction rate calculation) between ENDF/B-VI.3 and ENDF/B-VII.O. Differences between ENDF/B-VI.3 and ENDF/B-VII.O libraries are due to 16O, 1H, 90Zr, 91Zr, 92Zr, 238U, and 239Pu evaluations. Both ENDF/B-VI.3 and ENDF/B-VII.O library calculated reaction rates are within 20% of measurement and meet the criterion specified in the U. S. Nuclear Regulatory Commission Regulatory Guide 1.190, "Calculational and Dosimetry Methods for Determining Pressure Vessel Neutron Fluence."

  18. Newtonian CAFE: a new ideal MHD code to study the solar atmosphere

    NASA Astrophysics Data System (ADS)

    González, J. J.; Guzmán, F.

    2015-12-01

    In this work we present a new independent code designed to solve the equations of classical ideal magnetohydrodynamics (MHD) in three dimensions, submitted to a constant gravitational field. The purpose of the code centers on the analysis of solar phenomena within the photosphere-corona region. In special the code is capable to simulate the propagation of impulsively generated linear and non-linear MHD waves in the non-isothermal solar atmosphere. We present 1D and 2D standard tests to demonstrate the quality of the numerical results obtained with our code. As 3D tests we present the propagation of MHD-gravity waves and vortices in the solar atmosphere. The code is based on high-resolution shock-capturing methods, uses the HLLE flux formula combined with Minmod, MC and WENO5 reconstructors. The divergence free magnetic field constraint is controlled using the Flux Constrained Transport method.

  19. MHD forced convection flow adjacent to a non-isothermal wedge

    SciTech Connect

    Yih, K.A.

    1999-08-01

    The problem of magnetohydrodynamic (MHD) incompressible viscous flow has many important engineering applications in devices such as MHD power generator and the cooling of reactors. In this analysis, the effects of viscous dissipation and stress work on the MHD forced convection adjacent to a non-isothermal wedge is numerically analyzed. These partial differential equations are transformed into the nonsimilar boundary layer equations and solved by the Keller box method. Numerical results for the local friction coefficient and the local Nusselt number are presented for the pressure gradient parameter m, the magnetic parameter {xi}, the Prandtl number Pr, and the Eckert number Ec. In general, increasing the pressure gradient parameter m or the magnetic parameter {xi} or the Prandtl number Pr or decreasing the Eckert number EC increases the local Nusselt number.

  20. Dipole Alignment in Rotating MHD Turbulence

    NASA Technical Reports Server (NTRS)

    Shebalin, John V.; Fu, Terry; Morin, Lee

    2012-01-01

    We present numerical results from long-term CPU and GPU simulations of rotating, homogeneous, magnetohydrodynamic (MHD) turbulence, and discuss their connection to the spherically bounded case. We compare our numerical results with a statistical theory of geodynamo action that has evolved from the absolute equilibrium ensemble theory of ideal MHD turbulence, which is based on the ideal MHD invariants are energy, cross helicity and magnetic helicity. However, for rotating MHD turbulence, the cross helicity is no longer an exact invariant, although rms cross helicity becomes quasistationary during an ideal MHD simulation. This and the anisotropy imposed by rotation suggests an ansatz in which an effective, nonzero value of cross helicity is assigned to axisymmetric modes and zero cross helicity to non-axisymmetric modes. This hybrid statistics predicts a large-scale quasistationary magnetic field due to broken ergodicity , as well as dipole vector alignment with the rotation axis, both of which are observed numerically. We find that only a relatively small value of effective cross helicity leads to the prediction of a dipole moment vector that is closely aligned (less than 10 degrees) with the rotation axis. We also discuss the effect of initial conditions, dissipation and grid size on the numerical simulations and statistical theory.

  1. Markedly enhanced visible-light photocatalytic H2 generation over g-C3N4 nanosheets decorated by robust nickel phosphide (Ni12P5) cocatalysts.

    PubMed

    Wen, Jiuqing; Xie, Jun; Shen, Rongchen; Li, Xin; Luo, XingYi; Zhang, Hongdan; Zhang, Aiping; Bi, Guican

    2017-02-14

    In the present work, nickel phosphide (Ni12P5) modified graphitic carbon nitride (g-C3N4) nanosheets were synthesized by a simple grinding method. The structural characterization clearly proved that Ni12P5 nanoparticles were well loaded on the surface of g-C3N4 nanosheets. The photocatalytic activity of the composites was tested by catalyzing the reduction of water to hydrogen under visible light irradiation. The results demonstrate that Ni12P5 is an efficient co-catalyst for photocatalytic H2 production of g-C3N4 nanosheets. The maximum photocatalytic H2-production rate of 126.61 μmol g(-1) h(-1) could be obtained by loading 2.0% Ni12P5 nanoparticles on the surface of g-C3N4, which is about 269.4 times higher than that of pure g-C3N4. It is believed that Ni12P5 nanoparticles on the surface of g-C3N4 could act as significant active sites to boost separation of photoexcited electrons and holes and accelerate the H2-evolution kinetics, thus achieving greatly enhanced hydrogen generation. It is expected that this work could contribute to further experimental investigation for exploiting the low cost, high-efficiency, and environmentally friendly g-C3N4-based nanocomposites for photocatalytic H2 production.

  2. Generation of a Slc39a8 hypomorph mouse: Markedly decreased ZIP8 Zn{sup 2+}/(HCO{sub 3}{sup -}){sub 2} transporter expression

    SciTech Connect

    Wang, Bin; He, Lei; Dong, Hongbin; Dalton, Timothy P.; Nebert, Daniel W.

    2011-07-01

    Highlights: {yields} The mouse Slc39a8 gene encodes the ZIP8 transporter. {yields} ZIP8 functions endogenously as a electroneutral Zn{sup 2+}/(HCO{sub 3}{sup -}){sub 2} symporter. {yields} A Slc39a8(neo/neo) hypomorph mouse, due to retention of the neo mini-gene, has been created. {yields} ZIP8 expression in utero is {approx}90% decreased in all tissues examined. {yields} This mouse model will be useful for studying developmental and in utero physiological functions of ZIP8. -- Abstract: Previously this laboratory has identified the mouse Slc39a8 gene encoding the ZIP8 transporter, important in cadmium uptake. ZIP8 functions endogenously as a electroneutral Zn{sup 2+}/(HCO{sub 3}{sup -}){sub 2} symporter, moving both ions into the cell. The overall physiological importance of ZIP8 remains unclear. Herein we describe generation of a mouse line carrying the Slc39a8(neo) allele, containing the Frt-flanked neomycin-resistance (neo) mini-cassette in intron 3 and loxP sites in introns 3 and 6. Cre recombinase functions correctly in Escherichia coli and in adeno-Cre-infected mouse fetal fibroblasts, but does not function in the intact mouse for reasons not clear. Slc39a8(neo) is a hypomorphic allele, because Slc39a8(neo/neo) homozygotes exhibit dramatically decreased ZIP8 expression in embryo, fetus, and visceral yolk sac - in comparison to their littermate wild-type controls. This ZIP8 hypomorph will be instrumental in studying developmental and in utero physiological functions of the ZIP8 transporter.

  3. Multirail electromagnetic launcher powered from a pulsed magnetohydrodynamic generator

    NASA Astrophysics Data System (ADS)

    Afonin, A. G.; Butov, V. G.; Panchenko, V. P.; Sinyaev, S. V.; Solonenko, V. A.; Shvetsov, G. A.; Yakushev, A. A.

    2015-09-01

    The operation of an electromagnetic multirail launcher of solids powered from a pulsed magnetohydrodynamic (MHD) generator is studied. The plasma flow in the channel of the pulsed MHD generator and the possibility of launching solids in a rapid-fire mode of launcher operation are considered. It is shown that this mode of launcher operation can be implemented by matching the plasma flow dynamics in the channel of the pulsed MHD generator and the launching conditions. It is also shown that powerful pulsed MHD generators can be used as a source of electrical energy for rapid-fire electromagnetic rail launchers operating in a burst mode.

  4. GCF Mark IV development

    NASA Technical Reports Server (NTRS)

    Mortensen, L. O.

    1982-01-01

    The Mark IV ground communication facility (GCF) as it is implemented to support the network consolidation program is reviewed. Changes in the GCF are made in the area of increased capacity. Common carrier circuits are the medium for data transfer. The message multiplexing in the Mark IV era differs from the Mark III era, in that all multiplexing is done in a GCF computer under GCF software control, which is similar to the multiplexing currently done in the high speed data subsystem.

  5. Performance calculations for 200-1000 MWe MHD/steam power plants

    NASA Technical Reports Server (NTRS)

    Staiger, P. J.

    1981-01-01

    The effects of MHD generator length, level of oxygen enrichment, and oxygen production power on the performance of MHD/steam power plants ranging from 200 to 1000 MW in electrical output are investigated. The plants considered use oxygen enriched combustion air preheated to 1100 F. Both plants in which the MHD generator is cooled with low temperature and pressure boiler feedwater and plants in which the generator is cooled with high temperature and pressure boiler feedwater are considered. For plants using low temperature boiler feedwater for generator cooling the maximum thermodynamic efficiency is obtained with shorter generators and a lower level of oxygen enrichment compared to plants using high temperature boiler feedwater for generator cooling. The generator length at which the maximum plant efficiency occurs increases with power plant size for plants with a generator cooled by low temperature feedwater. Also shown is the relationship of the magnet stored energy requirement of the generator length and the power plant performance. Possible cost/performance tradeoffs between magnet cost and plant performance are indicated.

  6. Simulation of wave interactions with MHD

    SciTech Connect

    Batchelor, Donald B; Abla, G; Bateman, Glenn; Bernholdt, David E; Berry, Lee A; Bonoli, P.; Bramley, R; Breslau, J.; Chance, M.; Chen, J.; Choi, M.; Elwasif, Wael R; Fu, GuoYong; Harvey, R. W.; Jaeger, Erwin Frederick; Jardin, S. C.; Jenkins, T; Keyes, David E; Klasky, Scott A; Kruger, Scott; Ku, Long-Poe; Lynch, Vickie E; McCune, Douglas; Ramos, J.; Schissel, D.; Schnack,; Wright, J.

    2008-07-01

    The broad scientific objectives of the SWIM (Simulation of Wave Interaction with MHD) project are twofold: (1) improve our understanding of interactions that both radio frequency (RF) wave and particle sources have on extended-MHD phenomena, and to substantially improve our capability for predicting and optimizing the performance of burning plasmas in devices such as ITER: and (2) develop an integrated computational system for treating multiphysics phenomena with the required flexibility and extensibility to serve as a prototype for the Fusion Simulation Project. The Integrated Plasma Simulator (IPS) has been implemented. Presented here are initial physics results on RF effects on MHD instabilities in tokamaks as well as simulation results for tokamak discharge evolution using the IPS.

  7. MHD Equation of State with Relativistic Electrons

    NASA Astrophysics Data System (ADS)

    Gong, Zhigang; Däppen, Werner; Zejda, Ladislav

    2001-01-01

    The Mihalas-Däppen-Hummer (MHD) equation of state does not include the effect of relativistic partially degenerate electrons, although nonrelativistic partial degeneracy is taken into account. The discovery of a relativistic correction in helioseismology forces us to perform an appropriate upgrade of the MHD equation of state. We have adopted the method of J. M. Aparicio to evaluate the relativistic Fermi-Dirac functions. Our calculations confirm the validity of the approximation used, which works well for the weakly relativistic electrons under solar-center conditions. However, our results will also provide reliable thermodynamic quantities in the stronger relativistic regime as found in more massive stars. Since a particular feature of the original MHD papers was an explicit list of the adopted free energy and its first- and second-order analytical derivatives, we give the corresponding relativistic quantities in the Appendix.

  8. MHD simulations of supernova driven ISM turbulence

    NASA Astrophysics Data System (ADS)

    Gressel, Oliver; Ziegler, Udo

    The dynamic evolution of the (stratified) turbulent interstellar medium (ISM) is simulated utilizing a three-dimensional MHD model including various physical effects. The computational domain covers a box of 0.5x0.5x2.0 kpc at a resolution of typically 128x128x1024 grid cells. The model includes (constant kinematic) viscosity and magnetic diffusivity. The adiabatic equation of state is supplemented by a parameterized heating- and cooling-function allowing for thermal instability (TI). The update due to heating and cooling is implemented implicitly using a Patankar-type discretization. Turbulence is driven by supernova explosions which are modelled as local injections of thermal energy, smeared over three standard-deviations of a Gaussian support with FWHM of 20pc. Supernova rates are adopted for typical cited values. Within our model we make a distinction between Type I and Type II SNe. Latter are statistically clustered by the (artificial) constraint that the density at the explosion site be above average (with respect to a horizontal slab) - former are spatially uncorrelated. The dual-energy feature of the conservative NIRVANA-code is used to tackle the extreme ratio of kinetic to internal energy that arises from the violent energy input. We stress the importance of using a conservative scheme to properly transfer the injected energy to kinetic motion. The model also includes a differentially rotating background (with shearing boundary conditions in radial direction) as well as vertical stratification. The initial density and pressure profiles are in hydrostatic equilibrium with respect to the equation of state given by the radiative equilibrium. Including z-dependent heating rates this leads to a considerable deviation from usual isothermal initial models. The primary focus of this work is on the galactic dynamo and the generation of large-scale magnetic fields. As a secondary target we are also interested in general properties of the ISM that are of importance

  9. Vorticity equation for MHD fast waves in geospace environment

    SciTech Connect

    Yamauchi, M.; Lundin, R.; Lui, A.T.Y.

    1993-08-01

    The magnetohydrodynamic (MHD) vorticity equation is modified in order to apply it to nonlinear MHD fast waves or shocks when their extent along the magnetic field is limited. Field-aligned current (FAC) generation is also discussed on the basis of this modified vorticity equation. When the wave normal is not aligned to the finite velocity convection and the source region is spatially limited, a longitudinal polarization (u{sub {perpendicular}}{center_dot}J{sub {perpendicular}}) causes a pair of plus and minus charges inside the compressional plane waves or shocks, generating a pair of FACs. This polarization is not related to the separation between the electrons and ions caused by their difference in mass (i.e., Langmuir mode), a separation which is inherent to compressional waves. The resultant double field-aligned current structure exists both with and without the contributions from curvature drift, which is questionable in terms of its contribution to vorticity change from the viewpoint of single-particle motion. 14 refs., 3 figs.

  10. Laser production and heating of plasma for MHD application

    NASA Technical Reports Server (NTRS)

    Jalufka, N. W.

    1988-01-01

    Experiments have been made on the production and heating of plasmas by the absorption of laser radiation. These experiments were performed to ascertain the feasibility of using laser-produced or laser-heated plasmas as the input for a magnetohydrodynamic (MHD) generator. Such a system would have a broad application as a laser-to-electricity energy converter for space power transmission. Experiments with a 100-J-pulsed CO2 laser were conducted to investigate the breakdown of argon gas by a high-intensity laser beam, the parameters (electron density and temperature) of the plasma produced, and the formation and propagation of laser-supported detonation (LSD) waves. Experiments were also carried out using a 1-J-pulsed CO2 laser to heat the plasma produced in a shock tube. The shock-tube hydrogen plasma reached electron densities of approximately 10 to the 17th/cu cm and electron temperatures of approximately 1 eV. Absorption of the CO2 laser beam by the plasma was measured, and up to approximately 100 percent absorption was observed. Measurements with a small MHD generator showed that the energy extraction efficiency could be very large with values up to 56 percent being measured.

  11. Brain transplantation of genetically engineered human neural stem cells globally corrects brain lesions in the mucopolysaccharidosis type VII mouse.

    PubMed

    Meng, Xing-Li; Shen, Jin-Song; Ohashi, Toya; Maeda, Hiroshi; Kim, Seung Up; Eto, Yoshikatsu

    2003-10-15

    In the present study, we investigated the feasibility of using human neural stem cells (NSCs) in the treatment of diffuse central nervous system (CNS) alterations in a murine model of mucopolysaccharidosis VII (MPS VII), a lysosomal storage disease caused by a genetic defect in the beta-glucuronidase gene. An immortalized NSC line derived from human fetal telencephalon was genetically engineered to overexpress beta-glucuronidase and transplanted into the cerebral ventricles of neonatal MPS VII mouse. Transplanted human NSCs were found to integrate and migrate in the host brain and to produce large amount of beta-glucuronidase. Brain contents of the substrates of beta-glucuronidase were reduced to nearly normal levels, and widespread clearing of lysosomal storage was observed in the MPS VII mouse brain at 25 days posttransplantation. The number of engrafted cells decreased markedly after the transplantation, and it appears that the major cause of the cell death was not the immune response of the host but apoptotic cell death of grafted human NSCs. Results showed that human NSCs would serve as a useful gene transfer vehicle for the treatment of diffuse CNS lesions in human lysosomal storage diseases and are potentially applicable in the treatment of patients suffering from neurological disorders.

  12. Evaluation of the Effects of Ketoconazole and Voriconazole on the Pharmacokinetics of Oxcarbazepine and Its Main Metabolite MHD in Rats by UPLC-MS-MS.

    PubMed

    Chen, Xinxin; Gu, Ermin; Wang, Shuanghu; Zheng, Xiang; Chen, Mengchun; Wang, Li; Hu, Guoxin; Cai, Jian-ping; Zhou, Hongyu

    2016-03-01

    Oxcarbazepine (OXC), a second-generation antiepileptic drug, undergoes rapid reduction with formation of the active metabolite 10,11-dihydro-10-hydroxy-carbazepine (MHD) in vivo. In this study, a method for simultaneous determination of OXC and MHD in rat plasma using ultra-performance liquid chromatography with tandem mass spectrometry (UPLC-MS-MS) was developed and validated. Under given chromatographic conditions, OXC, MHD and internal standard diazepam were separated well and quantified by electrospray positive ionization mass spectrometry in the multiple reaction monitoring transitions mode. The method validation demonstrated good linearity over the range of 10-2,000 ng/mL for OXC and 5-1,000 ng/mL for MHD. The lower limit of quantification was 5 ng/mL for OXC and 2.5 ng/mL for MHD, respectively. The method was successfully applied to the evaluation of the pharmacokinetics of OXC and MHD in rats, with or without pretreatment by ketoconazole (KET) and voriconazole (VOR). Statistics indicated that KET and VOR significantly affected the disposition of OXC and MHD in vivo, whereas VOR predominantly interfered with the disposition of MHD. This method is suitable for pharmacokinetic study in small animals.

  13. Neon Induced MHD Activity in FTU

    NASA Astrophysics Data System (ADS)

    Botrugno, A.; Buratti, P.; Marinucci, M.; Mazzotta, C.; Pucella, G.; Romano, A.; Sozzi, C.

    The m/n=2/1 tearing instability driven by rapid increasing of the current density gradient near the q=2 radius induced by Ne puffing has discussed for different Frascati Tokamak Upgraded (FTU) L-mode ohmic plasmas. The dynamic of modes can be divided in three phases. The formation and dynamic of MHD activity strictly depends on the amount of Ne in plasma, for this reason, Ne puffing represents a very efficient method to deliberately induce formation of repeatable MHD targets for different experimental needs.

  14. 10 CFR 1045.40 - Marking requirements.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 4 2014-01-01 2014-01-01 false Marking requirements. 1045.40 Section 1045.40 Energy DEPARTMENT OF ENERGY (GENERAL PROVISIONS) NUCLEAR CLASSIFICATION AND DECLASSIFICATION Generation and Review of Documents Containing Restricted Data and Formerly Restricted Data § 1045.40 Marking...

  15. 10 CFR 1045.40 - Marking requirements.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 4 2011-01-01 2011-01-01 false Marking requirements. 1045.40 Section 1045.40 Energy DEPARTMENT OF ENERGY (GENERAL PROVISIONS) NUCLEAR CLASSIFICATION AND DECLASSIFICATION Generation and Review of Documents Containing Restricted Data and Formerly Restricted Data § 1045.40 Marking...

  16. 10 CFR 1045.40 - Marking requirements.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 4 2012-01-01 2012-01-01 false Marking requirements. 1045.40 Section 1045.40 Energy DEPARTMENT OF ENERGY (GENERAL PROVISIONS) NUCLEAR CLASSIFICATION AND DECLASSIFICATION Generation and Review of Documents Containing Restricted Data and Formerly Restricted Data § 1045.40 Marking...

  17. 10 CFR 1045.40 - Marking requirements.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 4 2013-01-01 2013-01-01 false Marking requirements. 1045.40 Section 1045.40 Energy DEPARTMENT OF ENERGY (GENERAL PROVISIONS) NUCLEAR CLASSIFICATION AND DECLASSIFICATION Generation and Review of Documents Containing Restricted Data and Formerly Restricted Data § 1045.40 Marking...

  18. 10 CFR 1045.40 - Marking requirements.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 4 2010-01-01 2010-01-01 false Marking requirements. 1045.40 Section 1045.40 Energy DEPARTMENT OF ENERGY (GENERAL PROVISIONS) NUCLEAR CLASSIFICATION AND DECLASSIFICATION Generation and Review of Documents Containing Restricted Data and Formerly Restricted Data § 1045.40 Marking...

  19. Experimental Study of MHD-Assisted Mixing and Combustion Under Low Pressure Conditions

    NASA Astrophysics Data System (ADS)

    Gao, Ling; Zhang, Bailing; Li, Yiwen; Fan, Hao; Duan, Chengduo; Wang, Yutian

    2016-08-01

    In order to reveal the mechanism of MHD-assisted mixing, and analyse the major parameters which influence the effect of MHD-assisted mixing, experiments of MHD-assisted mixing are carried out with a non-premixed butane-air combustion system. The evolvement of the discharge section and the effect of MHD-assisted mixing on combustion are investigated by changing the magnetic flux density and airflow velocity. The results show that the discharge area not only bends but also rotates around the centered wire electrode, which are mainly caused by the Lorentz force. Moreover, the highest curvature occurs near the centered wire electrode. The discharge localizes near the surface of the wire electrode and annular electrode when there is no ponderomotive force. However, if the ponderomotive force is applied, the discharge happens between these two electrodes and it gradually shrinks with time. The discharge area cannot localize near the annular electrode, which is due to the increase of energy loss in the airflow. When the airflow velocity exceeds a certain value, the discharge section becomes unstable because the injected energy cannot maintain the discharge. The rotation motion of the discharge section could enlarge the contact surface between butane and air, and is therefore beneficial for mixing and combustion. Magnetic flux density and airflow velocity are critical parameters for MHD-assisted mixing. supported by National Natural Science Foundation of China (No. 11372352) and the Mechanism Research on Near Electrode Thermal-Electromagnetic-Flow of High Temperature Supersonic MHD Generation (No. 51306207), and Natural Science Foundation of Shaanxi Province of China (No. 2015JM5184)

  20. The Mark 5C VLBI Data System

    NASA Technical Reports Server (NTRS)

    Whitney, Alan; Ruszczyk, Chester; Romney, Jon; Owens, Ken

    2010-01-01

    The Mark 5C disk-based VLBI data system is being developed as the third-generation Mark 5 disk-based system, increasing the sustained data-recording rate capability to 4 Gbps. It is built on the same basic platform as the Mark 5A, Mark 5B and Mark 5B+ systems and will use the same 8-disk modules as earlier Mark 5 systems, although two 8-disk modules will be necessary to support the 4 Gbps rate. Unlike its earlier brethren, which use proprietary data interfaces, the Mark 5C will accept data from a standard 10 Gigabit Ethernet connection and be compatible with the emerging VLBI Data Interchange Format (VDIF) standard. Data sources for the Mark 5C system will be based on new digital backends now being developed, specifically the RDBE in the U.S. and the dBBC in Europe, as well as others. The Mark 5C system is being planned for use with the VLBI2010 system and will also be used by NRAO as part of the VLBA sensitivity upgrade program; it will also be available to the global VLBI community from Conduant. Mark 5C system specification and development is supported by Haystack Observatory, NRAO, and Conduant Corporation. Prototype Mark 5C systems are expected in early 2010.

  1. Comparison of ENDF/B-VII.1 and ENDF/B-VII.0 Results for the Expanded Criticality Validation Suite for MCNP and for Selected Additional Criticality Benchmarks

    NASA Astrophysics Data System (ADS)

    Mosteller, R.

    2014-04-01

    Results obtained with the MCNP5 Monte Carlo code and the ENDF/B-VII.1 and ENDF/B-VII.0 nuclear data libraries have been compared for the 119 benchmarks in the expanded criticality validation suite for MCNP and for 23 additional benchmarks. ENDF/B-VII.1 was found to produce improvements relative to ENDF/B-VII.0 for benchmarks that contain significant amounts of tungsten, zirconium, cadmium, or beryllium, although the results for the benchmarks with beryllium suggest that further improvement still may be needed. In addition, a number of deficiencies previously identified for ENDF/B-VII.0 still remain in ENDF/B-VII.1.

  2. Exonuclease VII is involved in "reckless" DNA degradation in UV-irradiated Escherichia coli.

    PubMed

    Repar, Jelena; Briški, Nina; Buljubašić, Maja; Zahradka, Ksenija; Zahradka, Davor

    2013-01-20

    The recA mutants of Escherichia coli exhibit an abnormal DNA degradation that starts at sites of double-strand DNA breaks (DSBs), and is mediated by RecBCD exonuclease (ExoV). This "reckless" DNA degradation occurs spontaneously in exponentially growing recA cells, and is stimulated by DNA-damaging agents. We have previously found that the xonA and sbcD mutations, which inactivate exonuclease I (ExoI) and SbcCD nuclease, respectively, markedly suppress "reckless" DNA degradation in UV-irradiated recA cells. In the present work, we show that inactivation of exonuclease VII (ExoVII) by an xseA mutation contributes to attenuation of DNA degradation in UV-irradiated recA mutants. The xseA mutation itself has only a weak effect, however, it acts synergistically with the xonA or sbcD mutations in suppressing "reckless" DNA degradation. The quadruple xseA xonA sbcD recA mutants show no sign of DNA degradation during post-irradiation incubation, suggesting that ExoVII, together with ExoI and SbcCD, plays a crucial role in regulating RecBCD-catalyzed chromosome degradation. We propose that these nucleases act on DSBs to create blunt DNA ends, the preferred substrates for the RecBCD enzyme. In addition, our results show that in UV-irradiated recF recA(+) cells, the xseA, xonA, and sbcD mutations do not affect RecBCD-mediated DNA repair, suggesting that ExoVII, ExoI and SbcCD nucleases are not essential for the initial targeting of RecBCD to DSBs. It is possible that the DNA-blunting activity provided by ExoVII, ExoI and SbcCD is required for an exchange of RecBCD molecules on dsDNA ends during ongoing "reckless" DNA degradation.

  3. MHD Ballooning Instability in the Plasma Sheet

    SciTech Connect

    C.Z. Cheng; S. Zaharia

    2003-10-20

    Based on the ideal-MHD model the stability of ballooning modes is investigated by employing realistic 3D magnetospheric equilibria, in particular for the substorm growth phase. Previous MHD ballooning stability calculations making use of approximations on the plasma compressibility can give rise to erroneous conclusions. Our results show that without making approximations on the plasma compressibility the MHD ballooning modes are unstable for the entire plasma sheet where beta (sub)eq is greater than or equal to 1, and the most unstable modes are located in the strong cross-tail current sheet region in the near-Earth plasma sheet, which maps to the initial brightening location of the breakup arc in the ionosphere. However, the MHD beq threshold is too low in comparison with observations by AMPTE/CCE at X = -(8 - 9)R(sub)E, which show that a low-frequency instability is excited only when beq increases over 50. The difficulty is mitigated by considering the kinetic effects of ion gyrorad ii and trapped electron dynamics, which can greatly increase the stabilizing effects of field line tension and thus enhance the beta(sub)eq threshold [Cheng and Lui, 1998]. The consequence is to reduce the equatorial region of the unstable ballooning modes to the strong cross-tail current sheet region where the free energy associated with the plasma pressure gradient and magnetic field curvature is maximum.

  4. MHD (magnetohydrodynamics) instabilities in simple plasma configuration

    SciTech Connect

    Manheimer, W.M.; Lashmore-Davies, C.

    1984-01-01

    This work provides what, we hope, is a relatively simple, self contained description of MHD instabilities in plasmas with simple configurations. By simple configuration, we mean a plasma in which all quantities vary in only one spatial direction. We deal with such plasmas here because we want to emphasize the basic physics of MHD instabilities. Although some fusion devices are inherently two or three dimensional in nature, there are others, specifically tokamaks and reversed field pinches which are, to good approximation, one dimensional. Also, these devices both display a wealth of complex MHD activity which can be fruitfully discussed. One deceptive aspect of MHD instabilities is that the simplest ones are extremely easy to understand. However more complicated instabilities, for instance in a plasma where both an axial and azimuthal field are present are much more difficult to visualize; but they are also much more interesting. This work is divided into two parts. Chapters 2-9 describe linear theory and chapters 10-15 describe the nonlinear theory. The latter part is naturally much more speculative than the former because less is known about nonlinear theory.

  5. Analytical estimates of turbulent MHD transport coefficients

    NASA Technical Reports Server (NTRS)

    Montgomery, D.; Hatori, T.

    1984-01-01

    Turbulent transfer rates from small-scale MHD excitations to large-scale Fourier modes are calculated algebraically, using the method of Biskamp and Welter. Three cases are considered: two-dimensional Navier-Stokes flows, two-dimensional incompressible MHD, and the weakly three-dimensional Strauss equations. In all cases, an initially large spectral gap between the small-scale and large-scale excitations is assumed, and attention focusses on the initial values of the back-transfer rates. The sign of the transfer is determined by the sign of an analytically calculable eddy viscosity and/or anomalous resistivity. We are able to confirm the results of Biskamp and Welter for the case of two-dimensional MHD, but find some differences for the case of the Strauss equations. It is argued that the Strauss equations may not exhibit an inverse cascade phenomenon for the spatially periodic case unless their initial spectra are such that the behavior is essentially that of two-dimensional MHD.

  6. Robust and Efficient Riemann Solvers for MHD

    NASA Astrophysics Data System (ADS)

    Miyoshi, T.; Kusano, K.

    2008-04-01

    Robust and efficient approximate Riemann solvers for magnetohydrodynamics (MHD) are constructed. Particularly, a family of positively conservative Harten-Lax-van Leer (HLL)-type Riemann solvers, the so-called HLLD (`D' denotes Discontinuities), HLLR (`R' denotes Rotational), HLLC (`C' denotes Contact), and HLL solvers, is systematically considered.

  7. Featured Image: Tests of an MHD Code

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-09-01

    Creating the codes that are used to numerically model astrophysical systems takes a lot of work and a lot of testing! A new, publicly available moving-mesh magnetohydrodynamics (MHD) code, DISCO, is designed to model 2D and 3D orbital fluid motion, such as that of astrophysical disks. In a recent article, DISCO creator Paul Duffell (University of California, Berkeley) presents the code and the outcomes from a series of standard tests of DISCOs stability, accuracy, and scalability.From left to right and top to bottom, the test outputs shown above are: a cylindrical Kelvin-Helmholtz flow (showing off DISCOs numerical grid in 2D), a passive scalar in a smooth vortex (can DISCO maintain contact discontinuities?), a global look at the cylindrical Kelvin-Helmholtz flow, a Jupiter-mass planet opening a gap in a viscous disk, an MHD flywheel (a test of DISCOs stability), an MHD explosion revealing shock structures, an MHD rotor (a more challenging version of the explosion), a Flock 3D MRI test (can DISCO study linear growth of the magnetorotational instability in disks?), and a nonlinear 3D MRI test.Check out the gif below for a closer look at each of these images, or follow the link to the original article to see even more!CitationPaul C. Duffell 2016 ApJS 226 2. doi:10.3847/0067-0049/226/1/2

  8. Successive passaging of the scrapie strains, ME7-ha and 139A-ha, generated by the interspecies transmission of mouse-adapted strains into hamsters markedly shortens the incubation times, but maintains their molecular and pathological properties.

    PubMed

    Shi, Qi; Xiao, Kang; Zhang, Bao-Yun; Zhang, Xiao-Mei; Chen, Li-Na; Chen, Cao; Gao, Chen; Dong, Xiao-Ping

    2015-04-01

    As a type of zoonotic disease, prion diseases may be transmitted naturally and experimentally among species. In a previous study, we demonstrated that the mouse-adapted scrapie strains, ME7 (ME7-mo) and 139A (139A-mo), can overcome the species barrier and induce experimental scrapie when inoculated into Golden hamsters and generated 2 new hamster-adapted strains, ME7 (ME7-ha) and 139A (139A-ha). In the present study, in order to assess the infectivity and other molecular and neuropathological properties of the newly formed scrapie agents, ME7-ha and 139A-ha were further intracerebrally inoculated into hamsters. Compared with infection with 1st passage strains, the incubation times and clinical courses of infection with 2nd passage strains were markedly shorter, which were quite comparable with those of the mice infected with their parent mouse strains. The glycosylation patterns of brain PrP(Sc) in the animals infected with the 2nd passage of those 2 strains maintained similar features as those in the animals infected with the 1st passage of those strains, with predominantly diglycosylated PrP(Sc). Neuropathological assays revealed comparable spongiform degeneration and microglia proliferation in the brain tissues from the infected mice and hamsters, but markedly more plaque-like deposits of PrP(Sc) and more severe astrogliosis in the brains of the hamster. These data indicate that the strains, ME7-ha 1st and 139A-ha 1st generated by interspecies infection can passage in the new host hamster and stably maintain their molecular and neuropathological characteristics.

  9. 15 CFR Appendix Vii to Subpart P... - Areas To Be Avoided Boundary Coordinates

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 15 Commerce and Foreign Trade 3 2010-01-01 2010-01-01 false Areas To Be Avoided Boundary Coordinates VII Appendix VII to Subpart P of Part 922 Commerce and Foreign Trade Regulations Relating to... National Marine Sanctuary Pt. 922, Subpt. P, App. VII Appendix VII to Subpart P of Part 922—Areas To...

  10. 15 CFR Appendix Vii to Subpart P... - Areas To Be Avoided Boundary Coordinates

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 15 Commerce and Foreign Trade 3 2011-01-01 2011-01-01 false Areas To Be Avoided Boundary Coordinates VII Appendix VII to Subpart P of Part 922 Commerce and Foreign Trade Regulations Relating to... National Marine Sanctuary Pt. 922, Subpt. P, App. VII Appendix VII to Subpart P of Part 922—Areas To...

  11. 15 CFR Appendix Vii to Subpart P... - Areas To Be Avoided Boundary Coordinates

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 15 Commerce and Foreign Trade 3 2012-01-01 2012-01-01 false Areas To Be Avoided Boundary Coordinates VII Appendix VII to Subpart P of Part 922 Commerce and Foreign Trade Regulations Relating to... National Marine Sanctuary Pt. 922, Subpt. P, App. VII Appendix VII to Subpart P of Part 922—Areas To...

  12. 15 CFR Appendix Vii to Subpart P... - Areas To Be Avoided Boundary Coordinates

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 15 Commerce and Foreign Trade 3 2014-01-01 2014-01-01 false Areas To Be Avoided Boundary Coordinates VII Appendix VII to Subpart P of Part 922 Commerce and Foreign Trade Regulations Relating to... National Marine Sanctuary Pt. 922, Subpt. P, App. VII Appendix VII to Subpart P of Part 922—Areas To...

  13. 15 CFR Appendix Vii to Subpart P... - Areas To Be Avoided Boundary Coordinates

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 15 Commerce and Foreign Trade 3 2013-01-01 2013-01-01 false Areas To Be Avoided Boundary Coordinates VII Appendix VII to Subpart P of Part 922 Commerce and Foreign Trade Regulations Relating to... National Marine Sanctuary Pt. 922, Subpt. P, App. VII Appendix VII to Subpart P of Part 922—Areas To...

  14. Analysis of the Magneto-Hydrodynamic (MHD) Energy Bypass Engine for High-Speed Air-Breathing Propulsion

    NASA Technical Reports Server (NTRS)

    Riggins, David W.

    2002-01-01

    The performance of the MHD energy bypass air-breathing engine for high-speed propulsion is analyzed in this investigation. This engine is a specific type of the general class of inverse cycle engines. In this paper, the general relationship between engine performance (specific impulse and specific thrust) and the overall total pressure ratio through an engine (from inlet plane to exit plane) is first developed and illustrated. Engines with large total pressure decreases, regardless of cause or source, are seen to have exponentially decreasing performance. The ideal inverse cycle engine (of which the MHD engine is a sub-set) is then demonstrated to have a significant total pressure decrease across the engine; this total pressure decrease is cycle-driven, degrades rapidly with energy bypass ratio, and is independent of any irreversibility. The ideal MHD engine (inverse cycle engine with no irreversibility other than that inherent in the MHD work interaction processes) is next examined and is seen to have an additional large total pressure decrease due to MHD-generated irreversibility in the decelerator and the accelerator. This irreversibility mainly occurs in the deceleration process. Both inherent total pressure losses (inverse cycle and MHD irreversibility) result in a significant narrowing of the performance capability of the MHD bypass engine. The fundamental characteristics of MHD flow acceleration and flow deceleration from the standpoint of irreversibility and second-law constraints are next examined in order to clarify issues regarding flow losses and parameter selection in the MM modules. Severe constraints are seen to exist in the decelerator in terms of allowable deceleration Mach numbers and volumetric (length) required for meaningful energy bypass (work interaction). Considerable difficulties are also encountered and discussed due to thermal/work choking phenomena associated with the deceleration process. Lastly, full engine simulations utilizing inlet

  15. Development of MHD Wave Diagnostic and Models of Coronal Active Regions

    NASA Astrophysics Data System (ADS)

    Ofman, L.; Thompson, B. J.; Davila, J. M.

    2004-05-01

    We investigate the generation, propagation, and damping of MHD waves in active regions, with the goal to develop a diagnostic tool of active region structure, dynamics, and stability. We used 3D MHD model to study the generation and the propagation of EIT waves in a simple model of an active regions, and the interaction of EIT waves with the active region magnetic field. We model the oscillation of active region loops numerically using the 3D MHD model active regions. Such oscillations have been recently observed by TRACE. We use photospheric magnetograms as the boundary conditions for the magnetic field model, and construct an initial field using force-free extrapolation. Finite plasma temperature, density, and gravity are included in the model. We construct loop density structures in the model, guided by TRACE and EIT observations in the EUV. We demonstrate that by comparing the results of the MHD models of waves in an active region to observations we will be able to construct a diagnostic tool for the physical properties of the active regions, such as magnetic field and density structure.

  16. beta-Glucuronidase P408S, P415L mutations: evidence that both mutations combine to produce an MPS VII allele in certain Mexican patients.

    PubMed

    Islam, M R; Vervoort, R; Lissens, W; Hoo, J J; Valentino, L A; Sly, W S

    1996-09-01

    Mucopolysaccharidosis type VII (MPS VII, Sly syndrome) is an autosomal recessively inherited lysosomal storage disease caused by a deficiency in beta-glucuronidase. We identified and studied a novel allele containing two C-to-T transitions resulting in P408S and P415L alterations, which is present in homozygous state in one Mexican patient and in heterozygous state in another. None of the previous reports describing mutations in the MPS VII gene include Mexican patients. Expression of either of the mutations individually showed only modest effects on the properties of the enzyme. However, expression of the doubly mutant allele resulted in markedly reduced activity and rapid degradation in an early biosynthetic compartment.

  17. Symmetry, Statistics and Structure in MHD Turbulence

    NASA Technical Reports Server (NTRS)

    Shebalin, John V.

    2007-01-01

    Here, we examine homogeneous MHD turbulence in terms of truncated Fourier series. The ideal MHD equations and the associated statistical theory of absolute equilibrium ensembles are symmetric under P, C and T. However, the presence of invariant helicities, which are pseudoscalars under P and C, dynamically breaks this symmetry. This occurs because the surface of constant energy in phase space has disjoint parts, called components: while ensemble averages are taken over all components, a dynamical phase trajectory is confined to only one component. As the Birkhoff-Khinchin theorem tells us, ideal MHD turbulence is thus non-ergodic. This non-ergodicity manifests itself in low-wave number Fourier modes that have large mean values (while absolute ensemble theory predicts mean values of zero). Therefore, we have coherent structure in ideal MHD turbulence. The level of non-ergodicity and amount of energy contained in the associated coherent structure depends on the values of the helicities, as well as on the presence, or not, of a mean magnetic field and/or overall rotation. In addition to the well known cross and magnetic helicities, we also present a new invariant, which we call the parallel helicity, since it occurs when mean field and rotation axis are aligned. The question of applicability of these results to real (i.e., dissipative) MHD turbulence is also examined. Several long-time numerical simulations on a 64(exp 3) grid are given as examples. It is seen that coherent structure begins to form before decay dominates over nonlinearity. The connection of these results with inverse spectral cascades, selective decay, and magnetic dynamos is also discussed.

  18. Marking: A Critical Alternative.

    ERIC Educational Resources Information Center

    Hull, Charles

    1984-01-01

    Having pupils critique their own work is an alternative to marking that is worthy of consideration. Pupil critique fosters in students a willingness to take responsibility for the quality of their work products. (RM)

  19. Ames Fellows Award - Mark

    NASA Video Gallery

    Dr. Hans Mark is a leading expert in the fields of aerospace design and national defense policy. From 1969 to 1977, he served as Director of the NASA Ames Research Center. During his tenure, Ames b...

  20. The Fokker "Trimotor F VII" commercial transport monoplane

    NASA Technical Reports Server (NTRS)

    1928-01-01

    Directly developed from the single engined type F VII ten passenger monoplanes, The Fokker Trimotor closely follows the commercial aircraft that preceded it. It has three Wright Whirlwind air-cooled engines, rated at 200 HP each.

  1. Characteristics of a magnetohydrodynamic electrical power generator using convexly divergent channel

    NASA Astrophysics Data System (ADS)

    Murakami, Tomoyuki; Okuno, Yoshihiro

    2010-03-01

    We describe a magnetohydrodynamic (MHD) electrical power generator equipped with a convexly divergent channel, as determined through shock-tunnel-based experiments. The slight enhancement in a MHD channel divergence upstream provides boundary layer relief in a MHD flow decelerated by a retarding Lorentz force. Despite the present approach being simple and requiring a relatively minor modification of the MHD channel profile, the quality of MHD power-generating plasma and the energy conversion efficiency are improved compared to those from a previous linearly divergent channel; an excessive increase in static pressure is suppressed and a Hall field is enhanced, whereby notably high isentropic efficiency is achieved.

  2. Mark IVA microprocessor support

    NASA Technical Reports Server (NTRS)

    Burford, A. L.

    1982-01-01

    The requirements and plans for the maintenance support of microprocessor-based controllers in the Deep Space Network Mark IVA System are discussed. Additional new interfaces and 16-bit processors have introduced problems not present in the Mark III System. The need for continuous training of maintenance personnel to maintain a level of expertise consistent with the sophistication of the required tools is also emphasized.

  3. Computer simulation study of metastable ice VII and amorphous phases obtained by its melting

    NASA Astrophysics Data System (ADS)

    Slovák, Jan; Tanaka, Hideki

    2005-05-01

    Molecular dynamics simulations of metastable ice VII and cubic ice Ic are carried out in order to examine (1) the ability of commonly used water interaction potentials to reproduce the properties of ices, and (2) the possibility of generating low-density amorphous (LDA) structures by heating ice VII, which is known to transform to LDA at ˜135K at normal pressure [S. Klotz, J. M. Besson, G. Hamel, R. J. Nelmes, J. S. Loveday, and W. G. Marshall, Nature (London) 398, 681 (1999)]. We test four simple empirical interaction potentials of water: TIP4P [W. L. Jorgensen, J. Chandrasekhar, J. D. Madura, R. W. Impey, and M. L. Klein, J. Chem. Phys. 79, 926 (1983)], SPC/E [H. J. C. Berendsen, J. R. Grigera, and T. P. Straatsma, J. Phys. Chem. B 91, 6269 (1987)], TIP5P [M. W. Mahoney and W. L. Jorgensen, J. Chem. Phys. 112, 8910 (2000)], and ST2 [F. H. Stillinger and A. Rahman, J. Chem. Phys. 60, 1545 (1974)]. We have found that TIP5P ice VII melts at 210 K, TIP4P at 90 K, and SPC/E at 70 K. Only TIP5P water after transition has a structure similar to that of LDA. TIP4P and SPC/E have almost identical structures, dissimilar to any known water or amorphous phases, but upon heating both slowly evolve towards LDA-like structure. ST2 ice VII is remarkably stable up to 430 K. TIP4P and SPC/E predict correctly the cubic ice collapse into a high-density amorphous ice (HDA) at ˜1GPa whereas TIP5P remains stable up to ˜5GPa. The densities of the simulated ice phases differ significantly, depending on the potential used, and are generally higher than experimental values. The importance of proper treatment of long-range electrostatic interactions is also discussed.

  4. Computer simulation study of metastable ice VII and amorphous phases obtained by its melting.

    PubMed

    Slovák, Jan; Tanaka, Hideki

    2005-05-22

    Molecular dynamics simulations of metastable ice VII and cubic ice Ic are carried out in order to examine (1) the ability of commonly used water interaction potentials to reproduce the properties of ices, and (2) the possibility of generating low-density amorphous (LDA) structures by heating ice VII, which is known to transform to LDA at approximately 135 K at normal pressure [S. Klotz, J. M. Besson, G. Hamel, R. J. Nelmes, J. S. Loveday, and W. G. Marshall, Nature (London) 398, 681 (1999)]. We test four simple empirical interaction potentials of water: TIP4P [W. L. Jorgensen, J. Chandrasekhar, J. D. Madura, R. W. Impey, and M. L. Klein, J. Chem. Phys. 79, 926 (1983)], SPC/E [H. J. C. Berendsen, J. R. Grigera, and T. P. Straatsma, J. Phys. Chem. B 91, 6269 (1987)], TIP5P [M. W. Mahoney and W. L. Jorgensen, J. Chem. Phys. 112, 8910 (2000)], and ST2 [F. H. Stillinger and A. Rahman, J. Chem. Phys. 60, 1545 (1974)]. We have found that TIP5P ice VII melts at 210 K, TIP4P at 90 K, and SPC/E at 70 K. Only TIP5P water after transition has a structure similar to that of LDA. TIP4P and SPC/E have almost identical structures, dissimilar to any known water or amorphous phases, but upon heating both slowly evolve towards LDA-like structure. ST2 ice VII is remarkably stable up to 430 K. TIP4P and SPC/E predict correctly the cubic ice collapse into a high-density amorphous ice (HDA) at approximately 1 GPa whereas TIP5P remains stable up to approximately 5 GPa. The densities of the simulated ice phases differ significantly, depending on the potential used, and are generally higher than experimental values. The importance of proper treatment of long-range electrostatic interactions is also discussed.

  5. Meetings with Mark Vishik

    NASA Astrophysics Data System (ADS)

    Kalikinskaya, E. I.

    2014-12-01

    Mark Iosifovich Vishik was my husband Vladimir Chepyzhov's advisor during his years as a student in the Faculty of Mechanics and Mathematics at Moscow State University, and afterwards they worked together for almost 30 years. This is why I knew him personally while not being a mathematician myself: we sometimes talked on the phone, and met during common trips and a few holidays. In his last years, after the death of his devoted wife who was also his best friend, my husband and I decided to visit Mark regularly in order to comfort him in his loneliness, and many other of his friends did the same. I can say without exaggeration that Mark loved to talk with me about everyday matters, to reminisce about his wife Asya Moiseevna, their friends and relatives, to tell stories of his youth and the wonderful encounters that had so enriched his life. We had the idea to write down our conversations and publish them as a book. Unfortunately, few such conversations lay ahead. The last one took place in January 2010. We did not write a book, but we did write an article [1], which was published in English in the form of an interview with Mark. The present article is based on our conversations with Mark. Here I will try to recount his memories about people who played an important role in his life.

  6. Unsteady MHD Mixed Convection Slip Flow of Casson Fluid over Nonlinearly Stretching Sheet Embedded in a Porous Medium with Chemical Reaction, Thermal Radiation, Heat Generation/Absorption and Convective Boundary Conditions.

    PubMed

    Ullah, Imran; Bhattacharyya, Krishnendu; Shafie, Sharidan; Khan, Ilyas

    2016-01-01

    Numerical results are presented for the effect of first order chemical reaction and thermal radiation on mixed convection flow of Casson fluid in the presence of magnetic field. The flow is generated due to unsteady nonlinearly stretching sheet placed inside a porous medium. Convective conditions on wall temperature and wall concentration are also employed in the investigation. The governing partial differential equations are converted to ordinary differential equations using suitable transformations and then solved numerically via Keller-box method. It is noticed that fluid velocity rises with increase in radiation parameter in the case of assisting flow and is opposite in the case of opposing fluid while radiation parameter has no effect on fluid velocity in the forced convection. It is also seen that fluid velocity and concentration enhances in the case of generative chemical reaction whereas both profiles reduces in the case of destructive chemical reaction. Further, increase in local unsteadiness parameter reduces fluid velocity, temperature and concentration. Over all the effects of physical parameters on fluid velocity, temperature and concentration distribution as well as on the wall shear stress, heat and mass transfer rates are discussed in detail.

  7. MHD viscous Casson fluid flow and heat transfer with second-order slip velocity and thermal slip over a permeable stretching sheet in the presence of internal heat generation/absorption and thermal radiation

    NASA Astrophysics Data System (ADS)

    Megahed, Ahmed M.

    2015-04-01

    This article is devoted to describing the boundary layer flow and heat transfer for an electrically conducting Casson fluid over a permeable stretching surface with second-order slip velocity model and thermal slip conditions in the presence of internal heat generation/absorption and thermal radiation. The basic equations governing the flow and heat transfer are in the form of partial differential equations; the same have been reduced to a set of highly non-linear ordinary differential equations by applying suitable similarity transformations. Exact solution corresponding to momentum equation is obtained, and, in the case of no slip conditions, we get the exact solutions for both momentum and energy equation. The resulting similarity equations are solved numerically by shooting method. Comparisons with previously published work are performed and the results are found to be in excellent agreement. In the present work the effect of magnetic parameter, suction/injection parameter, Casson parameter, slip parameters, radiation parameter, internal heat generation/absorption parameter and the Prandtl number on flow and heat transfer characteristics have been discussed. Also, the local skin-friction coefficient and the local Nusselt number at the sheet are computed and discussed. It is found that the temperature rises to a higher value when the Casson parameter increases but the reverse is true for the velocity distribution. Finally, increasing the velocity and thermal slip parameters makes the rate of heat transfer decrease.

  8. Unsteady MHD Mixed Convection Slip Flow of Casson Fluid over Nonlinearly Stretching Sheet Embedded in a Porous Medium with Chemical Reaction, Thermal Radiation, Heat Generation/Absorption and Convective Boundary Conditions

    PubMed Central

    Ullah, Imran; Bhattacharyya, Krishnendu; Shafie, Sharidan; Khan, Ilyas

    2016-01-01

    Numerical results are presented for the effect of first order chemical reaction and thermal radiation on mixed convection flow of Casson fluid in the presence of magnetic field. The flow is generated due to unsteady nonlinearly stretching sheet placed inside a porous medium. Convective conditions on wall temperature and wall concentration are also employed in the investigation. The governing partial differential equations are converted to ordinary differential equations using suitable transformations and then solved numerically via Keller-box method. It is noticed that fluid velocity rises with increase in radiation parameter in the case of assisting flow and is opposite in the case of opposing fluid while radiation parameter has no effect on fluid velocity in the forced convection. It is also seen that fluid velocity and concentration enhances in the case of generative chemical reaction whereas both profiles reduces in the case of destructive chemical reaction. Further, increase in local unsteadiness parameter reduces fluid velocity, temperature and concentration. Over all the effects of physical parameters on fluid velocity, temperature and concentration distribution as well as on the wall shear stress, heat and mass transfer rates are discussed in detail. PMID:27776174

  9. MHD Integrated Topping Cycle Project. Thirteenth quarterly technical progress report, August 1, 1990--October 31, 1990

    SciTech Connect

    Not Available

    1992-01-01

    The overall objective of the project is to design and construct prototypical hardware for an integrated MHD topping cycle, and conduct long duration proof-of-concept tests of integrated system at the US DOE Component Development and Integration Facility in Butte, Montana. The results of the long duration tests will augment the existing engineering design data base on MHD power train reliability, availability, maintainability, and performance, and will serve as a basis for scaling up the topping cycle design to the next level of development, an early commercial scale power plant retrofit. The components of the MHD power train to be designed, fabricated, and tested include: A slagging coal combustor with a rated capacity of 50 MW thermal input, capable of operation with an Eastern (Illinois {number_sign}6) or Western (Montana Rosebud) coal, a segmented supersonic nozzle, a supersonic MHD channel capable of generating at least 1.5 MW of electrical power, a segmented supersonic diffuser section to interface the channel with existing facility quench and exhaust systems, a complete set of current control circuits for local diagonal current control along the channel, and a set of current consolidation circuits to interface the channel with the existing facility inverter.

  10. Multimegawatt nuclear electric propulsion with gaseous and vapor core reactors with MHD

    NASA Astrophysics Data System (ADS)

    Knight, Travis; Anghaie, Samim; Smith, Blair; Houts, Michael

    2001-02-01

    This study investigated the development of a system concept for space power generation and nuclear electric propulsion based on a fissioning plasma core reactor (FPCR) with magnetohydrodynamic (MHD) power conversion system, coupled to a magnetoplasmadynamic (MPD) thruster. The FPCR is a liquid-vapor core reactor concept operating with metallic uranium or uranium tetrafluoride (UF4) vapor as the fissioning fuel and alkali metals or their fluorides as working fluid in a closed Rankine cycle with MHD energy conversion. Candidate working fluids include K, Li, Na, KF, LiF, NaF, etc. The system features core outlet temperatures of 3000 to 4000 K at pressures of about 1 to 10 MPa, MHD temperatures of 2000 to 3000 K, and radiator temperatures of 1200 to 2000 K. This combination of parameters offers the potential for low total system specific mass in the range of 0.4 to 0.6 kg/kWe. The MHD output could be coupled with minimal power conditioning to the variable specific impulse magnetoplasma rocket (VASIMR), MPD thrusters or other types of thruster for producing thrust at very high specific impulse (Isp=1500 to 10,000 s). .

  11. MHD compressor---expander conversion system integrated with GCR inside a deployable reflector

    SciTech Connect

    Tuninetti, G. . Research Div.); Botta, E.; Criscuolo, C.; Riscossa, P. . Nuclear Div.); Giammanco, F. . Dipt. di Fisica); Rosa-Clot, M. . Dipt. di Fisica)

    1989-04-20

    This work originates from the proposal MHD Compressor-Expander Conversion System Integrated with a GCR Inside a Deployable Reflector''. The proposal concerned an innovative concept of nuclear, closed-cycle MHD converter for power generation on space-based systems in the multi-megawatt range. The basic element of this converter is the Power Conversion Unit (PCU) consisting of a gas core reactor directly coupled to an MHD expansion channel. Integrated with the PCU, a deployable reflector provides reactivity control. The working fluid could be either uranium hexafluoride or a mixture of uranium hexafluoride and helium, added to enhance the heat transfer properties. The original Statement of Work, which concerned the whole conversion system, was subsequently redirected and focused on the basic mechanisms of neutronics, reactivity control, ionization and electrical conductivity in the PCU. Furthermore, the study was required to be inherently generic such that the study was required to be inherently generic such that the analysis an results can be applied to various nuclear reactor and/or MHD channel designs''.

  12. MHD heat and seed recovery technology project. Tenth quarterly report, April-June 1980

    SciTech Connect

    Petrick, M.; Johnson, T. R.

    1980-12-01

    The MHD Heat and Seed Recovery Technology Project at Argonne National Laboratory is obtaining information for the design and operation of the steam plant downstream of the MHD channel-diffuser, and of the seed regeneration process. The project goal is to supply the engineering data required in the design of components for prototype and demonstration MHD facilities. The primary effort of the HSR Technology Project at Argonne is directed toward experimental investigations of critical problem areas, such as (1) corrosion and erosion of refractories and metal alloys; (2) NO/sub x/ behavior in the radiant boiler and secondary combustor; (3) radiant boiler design to meet the multiple requirements of steam generation, NO/sub x/ decomposition, and seed-slag separation; (4) effects of solid or liquid seed deposits on heat transfer and gas flow in the steam and air heaters; (5) formation, growth, and deposition of seed-slag particles; and (6) character of the combustion gas effluents. These investigations are performed primarily in a 2-MW test facility, the Argonne MHD Process Engineering Laboratory (AMPEL). Other project activities are related to studies of the thermochemistry of the seed-slag combustion gas system, and evaluation of seed regeneration processes. Progress is reported.

  13. Towards a Scalable Fully-Implicit Fully-coupled Resistive MHD Formulation with Stabilized FE Methods

    SciTech Connect

    Shadid, J N; Pawlowski, R P; Banks, J W; Chacon, L; Lin, P T; Tuminaro, R S

    2009-06-03

    This paper presents an initial study that is intended to explore the development of a scalable fully-implicit stabilized unstructured finite element (FE) capability for low-Mach-number resistive MHD. The discussion considers the development of the stabilized FE formulation and the underlying fully-coupled preconditioned Newton-Krylov nonlinear iterative solver. To enable robust, scalable and efficient solution of the large-scale sparse linear systems generated by the Newton linearization, fully-coupled algebraic multilevel preconditioners are employed. Verification results demonstrate the expected order-of-acuracy for the stabilized FE discretization of a 2D vector potential form for the steady and transient solution of the resistive MHD system. In addition, this study puts forth a set of challenging prototype problems that include the solution of an MHD Faraday conduction pump, a hydromagnetic Rayleigh-Bernard linear stability calculation, and a magnetic island coalescence problem. Initial results that explore the scaling of the solution methods are presented on up to 4096 processors for problems with up to 64M unknowns on a CrayXT3/4. Additionally, a large-scale proof-of-capability calculation for 1 billion unknowns for the MHD Faraday pump problem on 24,000 cores is presented.

  14. The PCB mark

    SciTech Connect

    1994-12-01

    Polychlorinated biphenyls (PCBs) are a class of organic chemicals that had become widely used in industrial applications due to their practical physical and chemical properties. Historical uses of PCBs include dielectric fluids (used in utility transformers, capacitors, etc.), hydraulic fluids, and other applications requiring stable, fire-retardant materials. Due to findings that PCBs may cause adverse health effects and due to their persistence and accumulation in the environment. The Toxic Substances Control Act (TSCA), enacted on October 11, 1976, banned the manufacture of PCBs after 1978 [Section 6(e)]. The first PCB regulations, promulgated at 40 CFR Part 761, were finalized on February 17, 1978. These PCB regulations include requirements specifying disposal methods and marking (labeling) procedures, and controlling PCB use. To assist the Department of Energy (DOE) in its efforts to comply with the TSCA statute and implementing regulations, the Office of Environmental Guidance has prepared the document ``Guidance on the Management of Polychlorinated Biphenyls (PCBs).`` That document explains the requirements specified in the statute and regulations for managing PCBs including PCB use, storage, transport, and disposal. The requirements outlined at 40 CFR 761.40 through 761.45 specify marking requirements for most PCB items (i.e., any PCB Article, PCB Container, PCB Article Container, or PCB Equipment that contains PCBs). Most PCB items require PCB marks, which are defined as a descriptive name, instructions, cautions, or other information applied to PCB Items or other objects subject to these regulations. The marking regulations include requirements for PCB marks on PCB Items, storage areas, and temporary storage areas. This Information Brief supplements the PCB guidance document by responding to common questions concerning marking requirements for PCBs. It is one of a series of Information Briefs pertinent to PCB management issues.

  15. Benchmarking ENDF/B-VII.0

    NASA Astrophysics Data System (ADS)

    van der Marck, Steven C.

    2006-12-01

    The new major release VII.0 of the ENDF/B nuclear data library has been tested extensively using benchmark calculations. These were based upon MCNP-4C3 continuous-energy Monte Carlo neutronics simulations, together with nuclear data processed using the code NJOY. Three types of benchmarks were used, viz., criticality safety benchmarks, (fusion) shielding benchmarks, and reference systems for which the effective delayed neutron fraction is reported. For criticality safety, more than 700 benchmarks from the International Handbook of Criticality Safety Benchmark Experiments were used. Benchmarks from all categories were used, ranging from low-enriched uranium, compound fuel, thermal spectrum ones (LEU-COMP-THERM), to mixed uranium-plutonium, metallic fuel, fast spectrum ones (MIX-MET-FAST). For fusion shielding many benchmarks were based on IAEA specifications for the Oktavian experiments (for Al, Co, Cr, Cu, LiF, Mn, Mo, Si, Ti, W, Zr), Fusion Neutronics Source in Japan (for Be, C, N, O, Fe, Pb), and Pulsed Sphere experiments at Lawrence Livermore National Laboratory (for 6Li, 7Li, Be, C, N, O, Mg, Al, Ti, Fe, Pb, D 2O, H 2O, concrete, polyethylene and teflon). For testing delayed neutron data more than thirty measurements in widely varying systems were used. Among these were measurements in the Tank Critical Assembly (TCA in Japan) and IPEN/MB-01 (Brazil), both with a thermal spectrum, and two cores in Masurca (France) and three cores in the Fast Critical Assembly (FCA, Japan), all with fast spectra. In criticality safety, many benchmarks were chosen from the category with a thermal spectrum, low-enriched uranium, compound fuel (LEU-COMP-THERM), because this is typical of most current-day reactors, and because these benchmarks were previously underpredicted by as much as 0.5% by most nuclear data libraries (such as ENDF/B-VI.8, JEFF-3.0). The calculated results presented here show that this underprediction is no longer there for ENDF/B-VII.0. The average over 257

  16. Numerical MHD codes for modeling astrophysical flows

    NASA Astrophysics Data System (ADS)

    Koldoba, A. V.; Ustyugova, G. V.; Lii, P. S.; Comins, M. L.; Dyda, S.; Romanova, M. M.; Lovelace, R. V. E.

    2016-05-01

    We describe a Godunov-type magnetohydrodynamic (MHD) code based on the Miyoshi and Kusano (2005) solver which can be used to solve various astrophysical hydrodynamic and MHD problems. The energy equation is in the form of entropy conservation. The code has been implemented on several different coordinate systems: 2.5D axisymmetric cylindrical coordinates, 2D Cartesian coordinates, 2D plane polar coordinates, and fully 3D cylindrical coordinates. Viscosity and diffusivity are implemented in the code to control the accretion rate in the disk and the rate of penetration of the disk matter through the magnetic field lines. The code has been utilized for the numerical investigations of a number of different astrophysical problems, several examples of which are shown.

  17. Amplitudes of MHD Waves in Sunspots

    NASA Astrophysics Data System (ADS)

    Norton, Aimee Ann; Cally, Paul; Baldner, Charles; Kleint, Lucia; Tarbell, Theodore D.; De Pontieu, Bart; Scherrer, Philip H.; Rajaguru, Paul

    2016-05-01

    The conversion of p-modes into MHD waves by strong magnetic fields occurs mainly in the sub-photospheric layers. The photospheric signatures of MHD waves are weak due to low amplitudes at the beta=1 equipartion level where mode-conversion occurs. We report on small amplitude oscillations observed in the photosphere with Hinode SOT/SP in which we analyze time series for sunspots ARs 12186 (11.10.2014) and 12434 (17.10.2015). No significant magnetic field oscillations are recovered in the umbra or penumbra in the ME inversion. However, periodicities in the inclination angle are found at the umbral/penumbral boundary with 5 minute periods. Upward propagating waves are indicated in the intensity signals correlated between HMI and AIA at different heights. We compare SP results with the oscillations observed in HMI data. Simultaneous IRIS data shows transition region brightening above the umbral core.

  18. The Termination Shock and Beyond: MHD Modeling

    SciTech Connect

    Ratkiewicz, Romana; Grygorczuk, Jolanta; Ben-Jaffel, Lotfi

    2005-08-01

    The 3D MHD models of the solar wind - interstellar plasma interaction including, in a self-consistent way, interactions of various populations of plasma and neutral particles should be ready to confront their results with the forthcoming data that will be obtained from space missions. In the near future, predictions made by sophisticated theoretical models should help refine the goals and optimize the capabilities of the instruments that will explore the far heliosphere and the LISM. In this paper we are giving a short survey of the MHD models and point out the problems, which need to be solved in the near future. As the example we show our recent numerical results with the simple model of the current sheet.

  19. Classical MHD shocks: theory and numerical simulation

    SciTech Connect

    Pogorelov, Nikolai V.

    2005-08-01

    Recent results are surveyed in the investigation of the behavior of shocks in ideal magnetohydrodynamics (MHD) and corresponding structures in dissipative/resistive plasma flows. In contrast to evolutionary shocks, a solution of the problem of the nonevolutionary shock interaction with small perturbations is either nonunique or does not exist. The peculiarity of non-ideal MHD is in that some nonevolutionary shocks have dissipative structures. Since this structure is always non-plane, it can reveal itself in problems where transverse perturbations do not exist due to symmetries restrictions. We discuss the numerical behavior of nonevolutionary shocks and argue that they necessarily disappear once the problem is solved in a genuinely three-dimensional statement.

  20. MHD processes in the outer heliosphere

    NASA Technical Reports Server (NTRS)

    Burlaga, L. F.

    1984-01-01

    The magnetic field measurements from Voyager and the magnetohydrodynamic (MHD) processes in the outer heliosphere are reviewed. A bibliography of the experimental and theoretical work concerning magnetic fields and plasmas observed in the outer heliosphere is given. Emphasis in this review is on basic concepts and dynamical processes involving the magnetic field. The theory that serves to explain and unify the interplanetary magnetic field and plasma observations is magnetohydrodynamics. Basic physical processes and observations that relate directly to solutions of the MHD equations are emphasized, but obtaining solutions of this complex system of equations involves various assumptions and approximations. The spatial and temporal complexity of the outer heliosphere and some approaches for dealing with this complexity are discussed.

  1. Coherent Eigenmodes in Homogeneous MHD Turbulence

    NASA Technical Reports Server (NTRS)

    Shebalin, John V.

    2010-01-01

    The statistical mechanics of Fourier models of ideal, homogeneous, incompressible magnetohydrodynamic (MHD) turbulence is discussed, along with their relevance for dissipative magnetofluids. Although statistical theory predicts that Fourier coefficients of fluid velocity and magnetic field are zero-mean random variables, numerical simulations clearly show that certain coefficients have a non-zero mean value that can be very large compared to the associated standard deviation, i.e., we have coherent structure. We use eigenanalysis of the modal covariance matrices in the probability density function to explain this phenomena in terms of `broken ergodicity', which is defined to occur when dynamical behavior does not match ensemble predictions on very long time-scales. We provide examples from 2-D and 3-D magnetohydrodynamic simulations of homogeneous turbulence, and show new results from long-time simulations of MHD turbulence with and without a mean magnetic field

  2. MHD shocks in coronal mass ejections

    NASA Technical Reports Server (NTRS)

    Steinolfson, R. S.

    1991-01-01

    The primary objective of this research program is the study of the magnetohydrodynamic (MHD) shocks and nonlinear simple waves produced as a result of the interaction of ejected lower coronal plasma with the ambient corona. The types of shocks and nonlinear simple waves produced for representative coronal conditions and disturbance velocities were determined. The wave system and the interactions between the ejecta and ambient corona were studied using both analytic theory and numerical solutions of the time-dependent, nonlinear MHD equations. Observations from the SMM coronagraph/polarimeter provided both guidance and motivation and are used extensively in evaluating the results. As a natural consequence of the comparisons with the data, the simulations assisted in better understanding the physical interactions in coronal mass ejections (CME's).

  3. Estimation of Specific Mass for Multimegawatt NEP Systems Based on Vapor Core Reactors with MHD Power Conversion

    NASA Astrophysics Data System (ADS)

    Knight, Travis; Anghaie, Samim

    2004-02-01

    Very low specific-mass power generation in space is possible using Vapor Core Reactors with Magnetohydrodynamic (VCR/MHD) generator. These advanced reactors at the conceptual design level have potential for the generation of tens to hundreds of megawatts of power in space with specific mass of about 1 kg/kWe. Power for nuclear electric propulsion (NEP) is possible with almost direct power conditioning and coupling of the VCR/MHD power output to the VASIMR engine, MPD, and a whole host of electric thrusters. The VCR/MHD based NEP system is designed to power space transportation systems that dramatically reduce the mission time for human exploration of the entire solar system or for aggressive long-term robotic missions. There are more than 40 years of experience in the evaluation of the scientific and technical feasibility of gas and vapor core reactor concepts. The proposed VCR is based on the concept of a cavity reactor made critical through the use of a reflector such as beryllium or beryllium oxide. Vapor fueled cavity reactors that are considered for NEP applications operate at maximum core center and wall temperatures of 4000 K and 1500K, respectively. A recent investigation has resulted in the conceptual design of a uranium tetrafluoride fueled vapor core reactor coupled to a MHD generator. Detailed neutronic design and cycle analyses have been performed to establish the operating design parameters for 10 to 200 MWe NEP systems. An integral system engineering-simulation code is developed to perform parametric analysis and design optimization studies for the VCR/MHD power system. Total system weight and size calculated based on existing technology has proven the feasibility of achieving exceptionally low specific mass (α ~1 kg/kWe) with a VCR/MHD powered system.

  4. Clinical course of sly syndrome (mucopolysaccharidosis type VII)

    PubMed Central

    Montaño, Adriana M; Lock-Hock, Ngu; Steiner, Robert D; Graham, Brett H; Szlago, Marina; Greenstein, Robert; Pineda, Mercedes; Gonzalez-Meneses, Antonio; Çoker, Mahmut; Bartholomew, Dennis; Sands, Mark S; Wang, Raymond; Giugliani, Roberto; Macaya, Alfons; Pastores, Gregory; Ketko, Anastasia K; Ezgü, Fatih; Tanaka, Akemi; Arash, Laila; Beck, Michael; Falk, Rena E; Bhattacharya, Kaustuv; Franco, José; White, Klane K; Mitchell, Grant A; Cimbalistiene, Loreta; Holtz, Max; Sly, William S

    2016-01-01

    Background Mucopolysaccharidosis VII (MPS VII) is an ultra-rare disease characterised by the deficiency of β-glucuronidase (GUS). Patients’ phenotypes vary from severe forms with hydrops fetalis, skeletal dysplasia and mental retardation to milder forms with fewer manifestations and mild skeletal abnormalities. Accurate assessments on the frequency and clinical characteristics of the disease have been scarce. The aim of this study was to collect such data. Methods We have conducted a survey of physicians to document the medical history of patients with MPS VII. The survey included anonymous information on patient demographics, family history, mode of diagnosis, age of onset, signs and symptoms, severity, management, clinical features and natural progression of the disease. Results We collected information on 56 patients from 11 countries. Patients with MPS VII were classified based on their phenotype into three different groups: (1) neonatal non-immune hydrops fetalis (NIHF) (n=10), (2) Infantile or adolescent form with history of hydrops fetalis (n=13) and (3) Infantile or adolescent form without known hydrops fetalis (n=33). Thirteen patients with MPS VII who had the infantile form with history of hydrops fetalis and survived childhood, had a wide range of clinical manifestations from mild to severe. Five patients underwent bone marrow transplantation and one patient underwent enzyme replacement therapy with recombinant human GUS. Conclusions MPS VII is a pan-ethnic inherited lysosomal storage disease with considerable phenotypical heterogeneity. Most patients have short stature, skeletal dysplasia, hepatosplenomegaly, hernias, cardiac involvement, pulmonary insufficiency and cognitive impairment. In these respects it resembles MPS I and MPS II. In MPS VII, however, one unique and distinguishing clinical feature is the unexpectedly high proportion of patients (41%) that had a history of NIHF. Presence of NIHF does not, by itself, predict the eventual severity

  5. Statistical Theory of the Ideal MHD Geodynamo

    NASA Technical Reports Server (NTRS)

    Shebalin, J. V.

    2012-01-01

    A statistical theory of geodynamo action is developed, using a mathematical model of the geodynamo as a rotating outer core containing an ideal (i.e., no dissipation), incompressible, turbulent, convecting magnetofluid. On the concentric inner and outer spherical bounding surfaces the normal components of the velocity, magnetic field, vorticity and electric current are zero, as is the temperature fluctuation. This allows the use of a set of Galerkin expansion functions that are common to both velocity and magnetic field, as well as vorticity, current and the temperature fluctuation. The resulting dynamical system, based on the Boussinesq form of the magnetohydrodynamic (MHD) equations, represents MHD turbulence in a spherical domain. These basic equations (minus the temperature equation) and boundary conditions have been used previously in numerical simulations of forced, decaying MHD turbulence inside a sphere [1,2]. Here, the ideal case is studied through statistical analysis and leads to a prediction that an ideal coherent structure will be found in the form of a large-scale quasistationary magnetic field that results from broken ergodicity, an effect that has been previously studied both analytically and numerically for homogeneous MHD turbulence [3,4]. The axial dipole component becomes prominent when there is a relatively large magnetic helicity (proportional to the global correlation of magnetic vector potential and magnetic field) and a stationary, nonzero cross helicity (proportional to the global correlation of velocity and magnetic field). The expected angle of the dipole moment vector with respect to the rotation axis is found to decrease to a minimum as the average cross helicity increases for a fixed value of magnetic helicity and then to increase again when average cross helicity approaches its maximum possible value. Only a relatively small value of cross helicity is needed to produce a dipole moment vector that is aligned at approx.10deg with the

  6. MHD simulations on an unstructured mesh

    SciTech Connect

    Strauss, H.R.; Park, W.; Belova, E.; Fu, G.Y.; Longcope, D.W.; Sugiyama, L.E.

    1998-12-31

    Two reasons for using an unstructured computational mesh are adaptivity, and alignment with arbitrarily shaped boundaries. Two codes which use finite element discretization on an unstructured mesh are described. FEM3D solves 2D and 3D RMHD using an adaptive grid. MH3D++, which incorporates methods of FEM3D into the MH3D generalized MHD code, can be used with shaped boundaries, which might be 3D.

  7. Laboratory-produced MHD plasma jets

    NASA Astrophysics Data System (ADS)

    Bellan, Paul

    2008-04-01

    Because space plasmas are neither confined by vacuum chamber walls nor have magnetic fields produced by physical coils, space plasmas have shapes that are much less determinate than lab plasmas. An experimental program underway at Caltech produces plasmas where the shape is neither fixed by a vacuum chamber wall nor imposed by an external coil set, but rather is allowed to be determined by self-organizing MHD processes subject to the constraint of imposed boundary conditions analogous to the boundary conditions of space plasmas. These self-organizing processes are believed to be fundamental to astrophysical jets, solar coronal loops, and MHD turbulence (e.g. Taylor relaxation). The experimental dynamics are sufficiently reproducible to allow detailed study despite the morphology being complex and dynamic. A surprising result has been the observation that instead of the plasma uniformly filling up the available volume, the plasma is spatially localized in a highly collimated, small diameter magnetic flux tube, the length and axis of which change in time in response to MHD forces. A model shows that the collimation results from stagnation of linked magnetic flux frozen into a MHD-driven jet that accelerates plasma from the wall into the flux tube, filling the flux tube with plasma. Jet flow has been imaged with a high-speed multi-frame camera, diagnosed via Doppler spectroscopy, and most recently (i) the collision between two opposing, color-coded jets flowing from opposite ends of a flux tube has been observed, and (ii) the collision of a jet with a target cloud has been observed.

  8. MHD Technology Transfer, Integration and Review Committee

    SciTech Connect

    Not Available

    1992-01-01

    This fifth semi-annual status report of the MHD Technology Transfer, Integration, and Review Committee (TTIRC) summarizes activities of the TTIRC during the period April 1990 through September 1990. It includes summaries and minutes of committee meetings, progress summaries of ongoing Proof-of-Concept (POC) contracts, discussions pertaining to technical integration issues in the POC program, and planned activities for the next six months.

  9. Magnetic reconnection in a compressible MHD plasma

    SciTech Connect

    Hesse, Michael; Zenitani, Seiji; Birn, Joachim

    2011-04-15

    Using steady-state resistive MHD, magnetic reconnection is reinvestigated for conditions of high resistivity/low magnetic Reynolds number, when the thickness of the diffusion region is no longer small compared to its length. Implicit expressions for the reconnection rate and other reconnection parameters are derived based on the requirements of mass, momentum, and energy conservation. These expressions are solved via simple iterative procedures. Implications specifically for low Reynolds number/high resistivity are being discussed.

  10. Magnetic Reconnection in a Compressible MHD Plasma

    NASA Technical Reports Server (NTRS)

    Hesse, Michael; Birn, Joachim; Zenitani, Seiji

    2011-01-01

    Using steady-state resistive MHD, magnetic reconnection is reinvestigated for conditions of high resistivity/low magnetic Reynolds number, when the thickness of the diffusion region is no longer small compared to its length. Implicit expressions for the reconnection rate and other reconnection parameters are derived based on the requirements of mass, momentum, and energy conservation. These expressions are solved via simple iterative procedures. Implications specifically for low Reynolds number/high resistivity are being discussed

  11. Inductive ionospheric solver for magnetospheric MHD simulations

    NASA Astrophysics Data System (ADS)

    Vanhamäki, H.

    2011-01-01

    We present a new scheme for solving the ionospheric boundary conditions required in magnetospheric MHD simulations. In contrast to the electrostatic ionospheric solvers currently in use, the new solver takes ionospheric induction into account by solving Faraday's law simultaneously with Ohm's law and current continuity. From the viewpoint of an MHD simulation, the new inductive solver is similar to the electrostatic solvers, as the same input data is used (field-aligned current [FAC] and ionospheric conductances) and similar output is produced (ionospheric electric field). The inductive solver is tested using realistic, databased models of an omega-band and westward traveling surge. Although the tests were performed with local models and MHD simulations require a global ionospheric solution, we may nevertheless conclude that the new solution scheme is feasible also in practice. In the test cases the difference between static and electrodynamic solutions is up to ~10 V km-1 in certain locations, or up to 20-40% of the total electric field. This is in agreement with previous estimates. It should also be noted that if FAC is replaced by the ground magnetic field (or ionospheric equivalent current) in the input data set, exactly the same formalism can be used to construct an inductive version of the KRM method originally developed by Kamide et al. (1981).

  12. Multi-dimensional MHD simple waves

    SciTech Connect

    Webb, G. M.; Ratkiewicz, R.; Brio, M.; Zank, G. P.

    1996-07-20

    In this paper we consider a formalism for multi-dimensional simple MHD waves using ideas developed by Boillat. For simple wave solutions one assumes that all the physical variables (the density {rho}, gas pressure p, fluid velocity u, gas entropy S, and magnetic induction B in the MHD case) depend on a single phase function {phi}(r,t). The simple wave solution ansatz and the MHD equations then require that the phase function {phi} satisfies an implicit equation of the form f({phi})=r{center_dot}n({phi})-{lambda}({phi})t, where n({phi})={nabla}{phi}/|{nabla}{phi}| is the wave normal, {lambda}({phi})={omega}/k=-{phi}{sub t}/|{nabla}{phi}| is the normal speed of the wave front, and f({phi}) is an arbitrary differentiable function of {phi}. The formalism allows for more general simple waves than that usually dealt with in which n({phi}) is a constant unit vector that does not vary along the wave front. The formalism has implications for shock formation and wave breaking for multi-dimensional waves.

  13. Multi-dimensional MHD simple waves

    NASA Technical Reports Server (NTRS)

    Webb, G. M.; Ratkiewicz, R.; Brio, M.; Zank, G. P.

    1995-01-01

    In this paper we consider a formalism for multi-dimensional simple MHD waves using ideas developed by Boillat. For simple wave solutions one assumes that all the physical variables (the density rho, gas pressure p, fluid velocity V, gas entropy S, and magnetic induction B in the MHD case) depend on a single phase function phi(r,t). The simple wave solution ansatz and the MHD equations then require that the phase function has the form phi = r x n(phi) - lambda(phi)t, where = n(phi) = Delta phi / (absolute value of Delta phi) is the wave normal and lambda(phi) = omega/k = -phi t / (absolute value of Delta phi) is the normal speed of the wave front. The formalism allows for more general simple waves than that usually dealt with in which n(phi) is a constant unit vector that does not vary along the wave front. The formalism has implications for shock formation for multi-dimensional waves.

  14. Building Action Principles for Extended MHD Models

    NASA Astrophysics Data System (ADS)

    Keramidas Charidakos, Ioannis; Lingam, Manasvi; Morrison, Philip; White, Ryan; Wurm, Alexander

    2014-10-01

    The general, non-dissipative, two-fluid model in plasma physics is Hamiltonian, but this property is sometimes lost in the process of deriving simplified two-fluid or one-fluid models from the two-fluid equations of motion. One way to ensure that the reduced models are Hamiltonian is to derive them from an action. We start with the general two-fluid action functional for an electron and an ion fluid interacting with an electromagnetic field, expressed in Lagrangian variables. We perform a change of variables and make various approximations (eg. quasineutrality and ordering of the fields) and small parameter expansions directly in the action. The resulting equations of motion are then mapped to the Eulerian fluid variables using a novel nonlocal Lagrange-Euler map. The correct Eulerian equations are obtained after we impose locality. Using this method and the proper approximations and expansions, we recover Lust's general two-fluid model, extended MHD, Hall MHD, and Electron MHD from a unified framework. The variational formulation allows us to use Noether's theorem to derive conserved quantities for each symmetry of the action. U.S. Dept. of Energy Contract # DE-FG05-80ET-53088, Western New England University Research Fund.

  15. The Statistical Mechanics of Ideal MHD Turbulence

    NASA Technical Reports Server (NTRS)

    Shebalin, John V.

    2003-01-01

    Turbulence is a universal, nonlinear phenomenon found in all energetic fluid and plasma motion. In particular. understanding magneto hydrodynamic (MHD) turbulence and incorporating its effects in the computation and prediction of the flow of ionized gases in space, for example, are great challenges that must be met if such computations and predictions are to be meaningful. Although a general solution to the "problem of turbulence" does not exist in closed form, numerical integrations allow us to explore the phase space of solutions for both ideal and dissipative flows. For homogeneous, incompressible turbulence, Fourier methods are appropriate, and phase space is defined by the Fourier coefficients of the physical fields. In the case of ideal MHD flows, a fairly robust statistical mechanics has been developed, in which the symmetry and ergodic properties of phase space is understood. A discussion of these properties will illuminate our principal discovery: Coherent structure and randomness co-exist in ideal MHD turbulence. For dissipative flows, as opposed to ideal flows, progress beyond the dimensional analysis of Kolmogorov has been difficult. Here, some possible future directions that draw on the ideal results will also be discussed. Our conclusion will be that while ideal turbulence is now well understood, real turbulence still presents great challenges.

  16. Modeling open boundaries in dissipative MHD simulation

    NASA Astrophysics Data System (ADS)

    Meier, E. T.; Glasser, A. H.; Lukin, V. S.; Shumlak, U.

    2012-04-01

    The truncation of large physical domains to concentrate computational resources is necessary or desirable in simulating many natural and man-made plasma phenomena. Three open boundary condition (BC) methods for such domain truncation of dissipative magnetohydrodynamics (MHD) problems are described and compared here. A novel technique, lacuna-based open boundary conditions (LOBC), is presented for applying open BC to dissipative MHD and other hyperbolic and mixed hyperbolic-parabolic systems of partial differential equations. LOBC, based on manipulating Calderon-type near-boundary sources, essentially damp hyperbolic effects in an exterior region attached to the simulation domain and apply BC appropriate for the remaining parabolic effects (if present) at the exterior region boundary. Another technique, approximate Riemann BC (ARBC), is adapted from finite volume and discontinuous Galerkin methods. In ARBC, the value of incoming flux is specified using a local, characteristic-based method. A third commonly-used open BC, zero-normal derivative BC (ZND BC), is presented for comparison. These open BC are tested in several gas dynamics and dissipative MHD problems. LOBC are found to give stable, low-reflection solutions even in the presence of strong parabolic behavior, while ARBC are stable only when hyperbolic behavior is dominant. Pros and cons of the techniques are discussed and put into context within the body of open BC research to date.

  17. Thermodynamic MHD Modeling of Coronal Mass Ejections

    NASA Astrophysics Data System (ADS)

    Linker, Jon A.; Lionello, R.; Mikic, Z.; Riley, P.; Titov, V.

    2007-05-01

    Coronal mass ejections (CMEs) disrupt the large-scale coronal magnetic field and propel plasma and magnetic flux outward into interplanetary space. The most energetic CMEs typically originate from active regions on the Sun. Accurately modeling active regions while also capturing the entire corona requires MHD models that include energy transport (radiative losses,anisotropic thermal conduction, and coronal heating) in the transition region and solar corona. We refer to this as the thermodynamic MHD model. The more accurate representation of energy flow in the thermodynamic MHD model allows us to to compute simulated EUV and X-ray emission as would be observed from spacecraft such as SOHO, STEREO, and Hinode. With this approach, theorists no longer get to argue what emission they think their favorite model's magnetic field evolution implies; we can actually go compute the emission and compare with observations. As an example, we show a simulation of the May 12, 1997 CME, and compare the simulated emission with observations from the actual event of dimming regions, postflare loops, and reformation of loops near the northern polar coronal hole. Work supported by NASA, NSF and the Center for Integrated Space Weather Modeling (an NSF Science and Technology Center).

  18. Anisotropic MHD model and some solutions

    SciTech Connect

    Kuznetsov, V. D.; Dzhalilov, N. S.

    2010-09-15

    MHD waves and instabilities in a collisionless anisotropic-pressure plasma are analyzed in an anisotropic MHD model based on the 16-moment approximation, and the results are found to agree well with those obtained in the low-frequency limit of the kinetic model. It is shown that accounting for heat fluxes leads to an asymmetry in the phase velocities of the wave modes with respect to the heat flux direction and also to a strong interaction between the modes, especially between the backward ones (those that propagate in a direction opposite to that of the heat flux). A correct description of the mirror instability is given. The resonant interaction of three backward modes-fast acoustic, fast magnetosonic, and slow acoustic-under the conditions for the onset of the classical firehose instability triggers a new type of instability the growth rate of which is faster than the maximum growth rate of the conventional firehose instability. The results prove that, in contrast to the familiar Chew-Goldberger-Low approximate model, the anisotropic MHD approach provides a correct description of the large-scale dynamics of collisionless anisotropic plasmas (such as solar corona, solar wind, and ionospheric and magnetospheric plasmas).

  19. MHD thrust vectoring of a rocket engine

    NASA Astrophysics Data System (ADS)

    Labaune, Julien; Packan, Denis; Tholin, Fabien; Chemartin, Laurent; Stillace, Thierry; Masson, Frederic

    2016-09-01

    In this work, the possibility to use MagnetoHydroDynamics (MHD) to vectorize the thrust of a solid propellant rocket engine exhaust is investigated. Using a magnetic field for vectoring offers a mass gain and a reusability advantage compared to standard gimbaled, elastomer-joint systems. Analytical and numerical models were used to evaluate the flow deviation with a 1 Tesla magnetic field inside the nozzle. The fluid flow in the resistive MHD approximation is calculated using the KRONOS code from ONERA, coupling the hypersonic CFD platform CEDRE and the electrical code SATURNE from EDF. A critical parameter of these simulations is the electrical conductivity, which was evaluated using a set of equilibrium calculations with 25 species. Two models were used: local thermodynamic equilibrium and frozen flow. In both cases, chlorine captures a large fraction of free electrons, limiting the electrical conductivity to a value inadequate for thrust vectoring applications. However, when using chlorine-free propergols with 1% in mass of alkali, an MHD thrust vectoring of several degrees was obtained.

  20. MHD edge instabilities in toroidal plasmas

    NASA Astrophysics Data System (ADS)

    Sugiyama, Linda

    2015-11-01

    Different types of MHD edge instabilities in different toroidal magnetically confined plasmas are compared. Large scale numerical simulations show that the nonlinear evolution of an unstable edge mode in a shaped plasma with a single X-point and a surrounding open field line region has a number of common features in the full resistive MHD model for strongly unstable and weaker instabilities. These include the relation of the nonlinear mode structure and dominant toroidal harmonics to the linear eigenmode spectrum, the effects of the mode on reducing the edge pressure or density gradient, the inward penetration of a ballooning-type perturbation into the plasma interior, and the potential to drive a coherent axisymmetric poloidal rotation of the outer part of the plasma, exhibited at different strengths. The results can be compared to experiment to estimate the usefulness and validity of the MHD model for predicting edge stability and instability properties. Work supported by the U.S. DOE OFES under Awards DE-SC-0007883, DE-FG02-04ER54802, and DE-SC-0008737. Some computation carried out at NERSC.

  1. Teaching with Mark Dion

    ERIC Educational Resources Information Center

    Fusaro, Joe

    2011-01-01

    Mark Dion creates sculptures, installations, and interactive environments that sometimes seem contrary to what one expects from visual artists. Remarkable curiosity cabinets and carefully arranged artifacts from specific places and time periods make up a large part of his work. His work does not neatly fit into traditional lessons about elements…

  2. Fathoming Mark Twain.

    ERIC Educational Resources Information Center

    Biggar, Joanna

    1988-01-01

    Relates the efforts of completing two collections of the works and papers of Mark Twain. Describes the combined efforts of the University of Iowa and the University of California to publish both a scholarly edition and a reader's edition devoted to Twain. (KO)

  3. Airbag bounce marks

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Looking east from the lander, the last few bounce marks as Pathfinder rolled to a stop on July 4 are visible in the soil in this image, taken by the Imager for Mars Pathfinder (IMP). The two most distant marks, identified by pointers in the image, consist of dark patches of disturbed soil. The three closest marks are clearly visible in the foreground, with one easily identifiable behind the Atmospheric Structure Instrument/Meteorology Package (ASI/MET) mast, is at right. The most distant positively identified bounce mark, indicated by the pointer at right, is approximately 11.3 meters (37 feet) from the lander.

    Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator. JPL is an operating division of the California Institute of Technology (Caltech).

  4. Rehab Mark. Participant's Workbook.

    ERIC Educational Resources Information Center

    Greenwood, Reed; And Others

    This manual is the employer-focused component workbook of a vocational rehabilitation program. Goals of the RehabMark approach include increased exposure of the rehabilitation agency in the local community, expanded contributions by the agency to community members, and services benefiting numerous clients simultaneously. The first half of the…

  5. Interview with Mark Ashwill

    ERIC Educational Resources Information Center

    Landsberger, Joe

    2006-01-01

    This article presents an interview with Mark Ashwill, Director of the Institute of International Education-Vietnam in Ha Noi, Vietnam, a branch of the Institute of International Education (IIE). In this interview, Ashwill talks about his work as Director of the Institute of International Education-Vietnam, the role that communications technology…

  6. Effective method for MHD retrofit of power plants

    SciTech Connect

    Berry, G.F.; Dennis, C.B.; Johnson, T.R.; Minkov, V.

    1981-10-01

    Retrofitting existing power plants with an open-cycle MHD system has been re-examined in light of recent developments in the heat and seed recovery technology area. A new retrofit cycle configuration has been developed which provides for a direct gas-gas coupling; also, the MHD topping cycle can be decoupled from the existing plant for either separate or joint operation. As an example, the MHD retrofit concept has been applied to Illinois Power Company's Vermilion Station No. 1, a coal-fired power plant presently in operation. Substantial increases in efficiency have been demonstrated and the economic validity of the MHD retrofit approach has been established.

  7. Shock-associated MHD waves - A model for interstellar density fluctuations

    NASA Technical Reports Server (NTRS)

    Spangler, Steven R.

    1988-01-01

    The possibility that the density fluctuations responsible for radio scintillations could be due to ion-beam-generated MHD waves near interstellar shock waves is discussed. This suggestion is inspired by spacecraft observations which reveal these phenomena near shocks in the solar system. The model quite naturally accounts for the scale on which these fluctuations occur; it is dictated by the wavelength of the unstable waves.

  8. VII International Congress of Engineering Physics

    NASA Astrophysics Data System (ADS)

    2015-01-01

    In the frame of the fortieth anniversary celebration of the Universidad Autónoma Metropolitana and the Physics Engineering career, the Division of Basic Science and Engineering and its Departments organized the "VII International Congress of Physics Engineering". The Congress was held from 24 to 28 November 2014 in Mexico City, Mexico. This congress is the first of its type in Latin America, and because of its international character, it gathers experts on physics engineering from Mexico and all over the globe. Since 1999, this event has shown research, articles, projects, technological developments and vanguard scientists. These activities aim to spread, promote, and share the knowledge of Physics Engineering. The topics of the Congress were: • Renewable energies engineering • Materials technology • Nanotechnology • Medical physics • Educational physics engineering • Nuclear engineering • High precision instrumentation • Atmospheric physics • Optical engineering • Physics history • Acoustics This event integrates lectures on top trending topics with pre-congress workshops, which are given by recognized scientists with an outstanding academic record. The lectures and workshops allow the exchange of experiences, and create and strengthen research networks. The Congress also encourages professional mobility among all universities and research centres from all countries. CIIF2014 Organizing and Editorial Committee Dr. Ernesto Rodrigo Vázquez Cerón Universidad Autónoma Metropolitana - Azcapotzalco ervc@correo.azc.uam.mx Dr. Luis Enrique Noreña Franco Universidad Autónoma Metropolitana - Azcapotzalco lnf@correo.azc.uam.mx Dr. Alberto Rubio Ponce Universidad Autónoma Metropolitana - Azcapotzalco arp@correo.azc.uam.mx Dr. Óscar Olvera Neria Universidad Autónoma Metropolitana - Azcapotzalco oon@correo.azc.uam.mx Professor Jaime Granados Samaniego Universidad Autónoma Metropolitana - Azcapotzalco jgs@correo.azc.uam.mx Dr. Roberto Tito Hern

  9. Mark Twain on phrenology.

    PubMed

    Stone, James L

    2003-12-01

    Mark Twain was a noted 19th century American writer and humorist. He often elaborated upon the personalities of his characters, and his observational skills reflected a strong interest in psychology. Similarly, he found an interest in phrenology, a pseudoscience that purported to characterize personality traits according to elevations or depressions on the head. Twain's style is clearly reflected in the interesting essay he wrote regarding his personal experience with phrenology.

  10. Understanding Accretion Disks through Three Dimensional Radiation MHD Simulations

    NASA Astrophysics Data System (ADS)

    Jiang, Yan-Fei

    I study the structures and thermal properties of black hole accretion disks in the radiation pressure dominated regime. Angular momentum transfer in the disk is provided by the turbulence generated by the magneto-rotational instability (MRI), which is calculated self-consistently with a recently developed 3D radiation magneto-hydrodynamics (MHD) code based on Athena. This code, developed by my collaborators and myself, couples both the radiation momentum and energy source terms with the ideal MHD equations by modifying the standard Godunov method to handle the stiff radiation source terms. We solve the two momentum equations of the radiation transfer equations with a variable Eddington tensor (VET), which is calculated with a time independent short characteristic module. This code is well tested and accurate in both optically thin and optically thick regimes. It is also accurate for both radiation pressure and gas pressure dominated flows. With this code, I find that when photon viscosity becomes significant, the ratio between Maxwell stress and Reynolds stress from the MRI turbulence can increase significantly with radiation pressure. The thermal instability of the radiation pressure dominated disk is then studied with vertically stratified shearing box simulations. Unlike the previous results claiming that the radiation pressure dominated disk with MRI turbulence can reach a steady state without showing any unstable behavior, I find that the radiation pressure dominated disks always either collapse or expand until we have to stop the simulations. During the thermal runaway, the heating and cooling rates from the simulations are consistent with the general criterion of thermal instability. However, details of the thermal runaway are different from the predictions of the standard alpha disk model, as many assumptions in that model are not satisfied in the simulations. We also identify the key reasons why previous simulations do not find the instability. The thermal

  11. Summary and evaluation of the conceptual design study of a potential early commercial MHD power plant (CSPEC)

    NASA Technical Reports Server (NTRS)

    Staiger, P. J.; Penko, P. F.

    1982-01-01

    The conceptual design study of a potential early commercial MHD power plant (CSPEC) is described and the results are summarized. Each of two contractors did a conceptual design of an approximtely 1000 MWe open-cycle MHD/steam plant with oxygen enriched combustion air preheated to an intermediate temperatue in a metallic heat exchanger. The contractors were close in their overall plant efficiency estimates but differed in their capital cost and cost of electricity estimates, primarily because of differences in balance-of-plant material, contingency, and operating and maintenance cost estimates. One contractor concluded that its MHD plant design compared favorably in cost of electricity with conventional coal-fired steam plants. The other contractor is making such a comparison as part of a follow-on study. Each contractor did a preliminary investigation of part-load performance and plant availability. The results of NASA studies investigating the effect of plant size and oxidizer preheat temperature on the performance of CSPEC-type MHD plants are also described. The efficiency of a 1000 MWe plant is about three points higher than of a 200 MWe plant. Preheating to 1600 F gives an efficiency about one and one-half points higher than preheating to 800 F for all plant sizes. For each plant size and preheat temperature there is an oxidizer enrichment level and MHD generator length that gives the highest plant efficiency.

  12. The preparation and structure of salty ice VII under pressure.

    PubMed

    Klotz, Stefan; Bove, Livia E; Strässle, Thierry; Hansen, Thomas C; Saitta, Antonino M

    2009-05-01

    It is widely accepted that ice, no matter what phase, is unable to incorporate large amounts of salt into its structure. This conclusion is based on the observation that on freezing of salt water, ice expels the salt almost entirely as brine. Here, we show that this behaviour is not an intrinsic physico-chemical property of ice phases. We demonstrate by neutron diffraction that substantial amounts of dissolved LiCl can be built homogeneously into the ice VII structure if it is produced by recrystallization of its glassy (amorphous) state under pressure. Such 'alloyed' ice VII has significantly different structural properties compared with pure ice VII, such as an 8% larger unit cell volume, 5 times larger displacement factors, an absence of a transition to an ordered ice VIII structure and plasticity. Our study suggests that there could be a whole new class of 'salty' high-pressure ice forms.

  13. A novel GUSB mutation in Brazilian terriers with severe skeletal abnormalities defines the disease as mucopolysaccharidosis VII.

    PubMed

    Hytönen, Marjo K; Arumilli, Meharji; Lappalainen, Anu K; Kallio, Heli; Snellman, Marjatta; Sainio, Kirsi; Lohi, Hannes

    2012-01-01

    Hundreds of different human skeletal disorders have been characterized at molecular level and a growing number of resembling dysplasias with orthologous genetic defects are being reported in dogs. This study describes a novel genetic defect in the Brazilian Terrier breed causing a congenital skeletal dysplasia. Affected puppies presented severe skeletal deformities observable within the first month of life. Clinical characterization using radiographic and histological methods identified delayed ossification and spondyloepiphyseal dysplasia. Pedigree analysis suggested an autosomal recessive disorder, and we performed a genome-wide association study to map the disease locus using Illumina's 22K SNP chip arrays in seven cases and eleven controls. A single association was observed near the centromeric end of chromosome 6 with a genome-wide significance after permutation (p(genome)= 0.033). The affected dogs shared a 13-Mb homozygous region including over 200 genes. A targeted next-generation sequencing of the entire locus revealed a fully segregating missense mutation (c.866C>T) causing a pathogenic p.P289L change in a conserved functional domain of β-glucuronidase (GUSB). The mutation was confirmed in a population of 202 Brazilian terriers (p = 7,71×10(-29)). GUSB defects cause mucopolysaccharidosis VII (MPS VII) in several species and define the skeletal syndrome in Brazilian Terriers. Our results provide new information about the correlation of the GUSB genotype to phenotype and establish a novel canine model for MPS VII. Currently, MPS VII lacks an efficient treatment and this model could be utilized for the development and validation of therapeutic methods for better treatment of MPS VII patients. Finally, since almost one third of the Brazilian terrier population carries the mutation, breeders will benefit from a genetic test to eradicate the detrimental disease from the breed.

  14. A Novel GUSB Mutation in Brazilian Terriers with Severe Skeletal Abnormalities Defines the Disease as Mucopolysaccharidosis VII

    PubMed Central

    Hytönen, Marjo K.; Arumilli, Meharji; Lappalainen, Anu K.; Kallio, Heli; Snellman, Marjatta; Sainio, Kirsi; Lohi, Hannes

    2012-01-01

    Hundreds of different human skeletal disorders have been characterized at molecular level and a growing number of resembling dysplasias with orthologous genetic defects are being reported in dogs. This study describes a novel genetic defect in the Brazilian Terrier breed causing a congenital skeletal dysplasia. Affected puppies presented severe skeletal deformities observable within the first month of life. Clinical characterization using radiographic and histological methods identified delayed ossification and spondyloepiphyseal dysplasia. Pedigree analysis suggested an autosomal recessive disorder, and we performed a genome-wide association study to map the disease locus using Illumina’s 22K SNP chip arrays in seven cases and eleven controls. A single association was observed near the centromeric end of chromosome 6 with a genome-wide significance after permutation (pgenome  = 0.033). The affected dogs shared a 13-Mb homozygous region including over 200 genes. A targeted next-generation sequencing of the entire locus revealed a fully segregating missense mutation (c.866C>T) causing a pathogenic p.P289L change in a conserved functional domain of β-glucuronidase (GUSB). The mutation was confirmed in a population of 202 Brazilian terriers (p = 7,71×10−29). GUSB defects cause mucopolysaccharidosis VII (MPS VII) in several species and define the skeletal syndrome in Brazilian Terriers. Our results provide new information about the correlation of the GUSB genotype to phenotype and establish a novel canine model for MPS VII. Currently, MPS VII lacks an efficient treatment and this model could be utilized for the development and validation of therapeutic methods for better treatment of MPS VII patients. Finally, since almost one third of the Brazilian terrier population carries the mutation, breeders will benefit from a genetic test to eradicate the detrimental disease from the breed. PMID:22815736

  15. MHD Electrode and wall constructions

    DOEpatents

    Way, Stewart; Lempert, Joseph

    1984-01-01

    Electrode and wall constructions for the walls of a channel transmitting the hot plasma in a magnetohydrodynamic generator. The electrodes and walls are made of a plurality of similar modules which are spaced from one another along the channel. The electrodes can be metallic or ceramic, and each module includes one or more electrodes which are exposed to the plasma and a metallic cooling bar which is spaced from the plasma and which has passages through which a cooling fluid flows to remove heat transmitted from the electrode to the cooling bar. Each electrode module is spaced from and electrically insulated from each adjacent module while interconnected by the cooling fluid which serially flows among selected modules. A wall module includes an electrically insulating ceramic body exposed to the plasma and affixed, preferably by mechanical clips or by brazing, to a metallic cooling bar spaced from the plasma and having cooling fluid passages. Each wall module is, similar to the electrode modules, electrically insulated from the adjacent modules and serially interconnected to other modules by the cooling fluid.

  16. MHD seed recovery/regeneration

    NASA Astrophysics Data System (ADS)

    Task 1 calls for the design, procurement, construction, and installation of the Seed Regeneration Proof-of-Concept Facility (SRPF) that will produce tonnage quantities of recyclable potassium formate seed at a design rate of 250 lb/hr for testing in the channel at the CDIF while collecting data that will be used to upgrade the design of a 300 MW(sub t) system. Approximately 12 tons of KCOOH (dry basis) as 70-75 wt percent solution were produced. The front end of the plant (potassium sulfate reaction and solids separation/washing units) was operated for five days in March. Most of the operations were conducted at a spent seed feed rate of 250 pounds/hour. A total of 8,500 gallons of dilute KCOOH solution was generated containing approximately 2.6 tons of potassium formate (dry basis). The average KCOOH content of this solution was 7 wt percent. The design KCOOH solution concentration for the front end of the plant is 8.5 wt percent. The evaporation unit was operated for a total of six days during March. Approximately 2.5 tons of potassium formate (dry basis) were processed through the evaporator and concentrated to greater then 7 wt percent.

  17. Laboratory Plasma Source as an MHD Model for Astrophysical Jets

    NASA Technical Reports Server (NTRS)

    Mayo, Robert M.

    1997-01-01

    The significance of the work described herein lies in the demonstration of Magnetized Coaxial Plasma Gun (MCG) devices like CPS-1 to produce energetic laboratory magneto-flows with embedded magnetic fields that can be used as a simulation tool to study flow interaction dynamic of jet flows, to demonstrate the magnetic acceleration and collimation of flows with primarily toroidal fields, and study cross field transport in turbulent accreting flows. Since plasma produced in MCG devices have magnetic topology and MHD flow regime similarity to stellar and extragalactic jets, we expect that careful investigation of these flows in the laboratory will reveal fundamental physical mechanisms influencing astrophysical flows. Discussion in the next section (sec.2) focuses on recent results describing collimation, leading flow surface interaction layers, and turbulent accretion. The primary objectives for a new three year effort would involve the development and deployment of novel electrostatic, magnetic, and visible plasma diagnostic techniques to measure plasma and flow parameters of the CPS-1 device in the flow chamber downstream of the plasma source to study, (1) mass ejection, morphology, and collimation and stability of energetic outflows, (2) the effects of external magnetization on collimation and stability, (3) the interaction of such flows with background neutral gas, the generation of visible emission in such interaction, and effect of neutral clouds on jet flow dynamics, and (4) the cross magnetic field transport of turbulent accreting flows. The applicability of existing laboratory plasma facilities to the study of stellar and extragalactic plasma should be exploited to elucidate underlying physical mechanisms that cannot be ascertained though astrophysical observation, and provide baseline to a wide variety of proposed models, MHD and otherwise. The work proposed herin represents a continued effort on a novel approach in relating laboratory experiments to

  18. Doppler displacements in kink MHD waves in solar flux tubes

    NASA Astrophysics Data System (ADS)

    Goossens, Marcel; Van Doorsselaere, Tom; Terradas, Jaume; Verth, Gary; Soler, Roberto

    Doppler displacements in kink MHD waves in solar flux tubes Presenting author: M. Goossens Co-authors: R. Soler, J. Terradas, T. Van Doorsselaere, G. Verth The standard interpretation of the transverse MHD waves observed in the solar atmosphere is that they are non-axisymmetric kink m=1) waves on magnetic flux tubes. This interpretation is based on the fact that axisymmetric and non-axisymmetric fluting waves do not displace the axis of the loop and the loop as a whole while kink waves indeed do so. A uniform transverse motion produces a Doppler displacement that is constant across the magnetic flux tube. A recent development is the observation of Doppler displacements that vary across the loop. The aim of the present contribution is to show that spatial variations of the Doppler displacements across the loop can be caused by kink waves. The motion associated with a kink wave is purely transverse only when the flux tube is uniform and sufficiently thin. Only in that case do the radial and azimuthal components of displacement have the same amplitude and is the azimuthal component a quarter of a period ahead of the radial component. This results in a unidirectional or transverse displacement. When the flux tube is non-uniform and has a non-zero radius the conditions for the generation of a purely transverse motion are not any longer met. In that case the motion in a kink wave is the sum of a transverse motion and a non-axisymmetric rotational motion that depends on the azimuthal angle. It can produce complicated variations of the Doppler displacement across the loop. I shall discuss the various cases of possible Doppler displacenents that can occur depending on the relative sizes of the amplitudes of the radial and azimuthal components of the displacement in the kink wave and on the orientation of the line of sight.

  19. 29 CFR 1604.8 - Relationship of title VII to the Equal Pay Act.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... GUIDELINES ON DISCRIMINATION BECAUSE OF SEX § 1604.8 Relationship of title VII to the Equal Pay Act. (a) The employee coverage of the prohibitions against discrimination based on sex contained in title VII...

  20. 29 CFR 1604.8 - Relationship of title VII to the Equal Pay Act.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... GUIDELINES ON DISCRIMINATION BECAUSE OF SEX § 1604.8 Relationship of title VII to the Equal Pay Act. (a) The employee coverage of the prohibitions against discrimination based on sex contained in title VII...

  1. Nonlinear MHD Waves in a Prominence Foot

    NASA Astrophysics Data System (ADS)

    Ofman, L.; Knizhnik, K.; Kucera, T.; Schmieder, B.

    2015-11-01

    We study nonlinear waves in a prominence foot using a 2.5D MHD model motivated by recent high-resolution observations with Hinode/Solar Optical Telescope in Ca ii emission of a prominence on 2012 October 10 showing highly dynamic small-scale motions in the prominence material. Observations of Hα intensities and of Doppler shifts show similar propagating fluctuations. However, the optically thick nature of the emission lines inhibits a unique quantitative interpretation in terms of density. Nevertheless, we find evidence of nonlinear wave activity in the prominence foot by examining the relative magnitude of the fluctuation intensity (δI/I ˜ δn/n). The waves are evident as significant density fluctuations that vary with height and apparently travel upward from the chromosphere into the prominence material with quasi-periodic fluctuations with a typical period in the range of 5-11 minutes and wavelengths <2000 km. Recent Doppler shift observations show the transverse displacement of the propagating waves. The magnetic field was measured with the THEMIS instrument and was found to be 5-14 G. For the typical prominence density the corresponding fast magnetosonic speed is ˜20 km s-1, in qualitative agreement with the propagation speed of the detected waves. The 2.5D MHD numerical model is constrained with the typical parameters of the prominence waves seen in observations. Our numerical results reproduce the nonlinear fast magnetosonic waves and provide strong support for the presence of these waves in the prominence foot. We also explore gravitational MHD oscillations of the heavy prominence foot material supported by dipped magnetic field structure.

  2. MHD Turbulence at Moderate Magnetic Reynolds Number

    NASA Technical Reports Server (NTRS)

    Knaepen, B.; Kassinos, S.; Carati, D.

    2003-01-01

    In the present article we will consider the decay of MHD turbulence under the influence of a strong external magnetic field at moderate magnetic Reynolds numbers. Typical values of R(sub m) that are considered here range from R(sub m) approx. 0.1 to R(sub m) approx. 20. As a comparison, the initial kinetic Reynolds number common to all our simulations is Re(sub L) = 199. This means that the range of Prandtl numbers explored is 5 x 10(exp -4) to 10(exp -1). Our motivation is mainly to exhibit how the transition from the QS approximation to FMHD occurs. At the lowest values of R(sub m) studied here, the QS approximation is shown to model the flow faithfully. However, for the higher values of R(sub m) considered, it is clearly inadequate but can be replaced by another approximation which will be referred to as the Quasi-Linear (QL) approximation. Another objective of the present study is to describe how variations in the magnetic Reynolds number (while maintaining all other parameters constant) affect the dynamics of the flow. This complements past studies where variations in either the strength of the external magnetic field or the kinetic Reynolds number were considered. This article is organized as follows. In section 2 we recall the definition of the quasi-static approximation. Section 3 is devoted to the description of the numerical experiments performed using the quasi-static approximation and full MHD. In section 4 we describe the quasi-linear approximation and test it numerically against full MHD. A concluding summary is given in section 5.

  3. NONLINEAR MHD WAVES IN A PROMINENCE FOOT

    SciTech Connect

    Ofman, L.; Knizhnik, K.; Kucera, T.; Schmieder, B.

    2015-11-10

    We study nonlinear waves in a prominence foot using a 2.5D MHD model motivated by recent high-resolution observations with Hinode/Solar Optical Telescope in Ca ii emission of a prominence on 2012 October 10 showing highly dynamic small-scale motions in the prominence material. Observations of Hα intensities and of Doppler shifts show similar propagating fluctuations. However, the optically thick nature of the emission lines inhibits a unique quantitative interpretation in terms of density. Nevertheless, we find evidence of nonlinear wave activity in the prominence foot by examining the relative magnitude of the fluctuation intensity (δI/I ∼ δn/n). The waves are evident as significant density fluctuations that vary with height and apparently travel upward from the chromosphere into the prominence material with quasi-periodic fluctuations with a typical period in the range of 5–11 minutes and wavelengths <2000 km. Recent Doppler shift observations show the transverse displacement of the propagating waves. The magnetic field was measured with the THEMIS instrument and was found to be 5–14 G. For the typical prominence density the corresponding fast magnetosonic speed is ∼20 km s{sup −1}, in qualitative agreement with the propagation speed of the detected waves. The 2.5D MHD numerical model is constrained with the typical parameters of the prominence waves seen in observations. Our numerical results reproduce the nonlinear fast magnetosonic waves and provide strong support for the presence of these waves in the prominence foot. We also explore gravitational MHD oscillations of the heavy prominence foot material supported by dipped magnetic field structure.

  4. Minimal Marking: A Success Story

    ERIC Educational Resources Information Center

    McNeilly, Anne

    2014-01-01

    The minimal-marking project conducted in Ryerson's School of Journalism throughout 2012 and early 2013 resulted in significantly higher grammar scores in two first-year classes of minimally marked university students when compared to two traditionally marked classes. The "minimal-marking" concept (Haswell, 1983), which requires…

  5. Case Marking Strategies in Kope.

    ERIC Educational Resources Information Center

    Clifton, John

    Case marking strategies in Kope, a Papuan language of Papua New Guinea, are analyzed in light of previous claims that most Papuan languages have one strategy for marking core relations and another for marking peripheral relations. A brief grammatical overview illustrates how core and peripheral relations are marked in Kope, including nominal case…

  6. Mark 3 system overview

    NASA Technical Reports Server (NTRS)

    Clark, T. A.

    1980-01-01

    The Mark 3 very long baseline interferometry (VLBI) system, comprising a complete end to end VLBI system optimized for both high accuracy geodesy and radio astronomy, is described. The data flow, the data base handler system, and the field station component and configurations are briefly discussed. The use of mobile and transportable stations allows measurements to be taken from a large number of sites with relatively few sets of equipment. Fixed stations form a long term reference network for tying together the measurements with the mobile and transportable stations.

  7. Magnetogasdynamic Phenomena in Pulsed MHD Flows.

    DTIC Science & Technology

    1979-10-01

    r D-A079 919 STD RESEARCH CORP ARCADIA CALIF F/a 20/9 VA NETOGASDYNAMIC PHENODE’A IN PULSED MHD FLOWS.(U) OCT 79 D A OLIVER, T F SWEAN. D M MARKHAN...N00014-77-C-0574 UNCLASSIFIED STD -UP-002-77-1 NL ".’ rnunnnnunnnnSllflflflflflflf lllll /////IlEEEEE//!i *fl///////lfl l I/fflIEN I2) STD -UP-002-77-1...DEMETRIADES OCTOBER 1979 --A li JTlrSUMMARY REPORT FOR THE PERIOD 1 OCTOBER 1978 THROUGH 30 SEPTEMBER 1979 STD RESEARCH CORPORATION ARCADIA, CA S1006 PREPARED

  8. MHD oxidant intermediate temperature ceramic heater study

    NASA Technical Reports Server (NTRS)

    Carlson, A. W.; Chait, I. L.; Saari, D. P.; Marksberry, C. L.

    1981-01-01

    The use of three types of directly fired ceramic heaters for preheating oxygen enriched air to an intermediate temperature of 1144K was investigated. The three types of ceramic heaters are: (1) a fixed bed, periodic flow ceramic brick regenerative heater; (2) a ceramic pebble regenerative heater. The heater design, performance and operating characteristics under conditions in which the particulate matter is not solidified are evaluated. A comparison and overall evaluation of the three types of ceramic heaters and temperature range determination at which the particulate matter in the MHD exhaust gas is estimated to be a dry powder are presented.

  9. Generations.

    PubMed

    Chambers, David W

    2005-01-01

    Groups naturally promote their strengths and prefer values and rules that give them an identity and an advantage. This shows up as generational tensions across cohorts who share common experiences, including common elders. Dramatic cultural events in America since 1925 can help create an understanding of the differing value structures of the Silents, the Boomers, Gen Xers, and the Millennials. Differences in how these generations see motivation and values, fundamental reality, relations with others, and work are presented, as are some applications of these differences to the dental profession.

  10. Apparatus for electrode current control in linear MHD generators

    DOEpatents

    Demirjian, Ara M.; Solbes, Albert

    1984-01-01

    Apparatus for controlling a plurality of opposing, electrode, direct-currents at pre-set locations across a channel that comprises a converter for converting each electrode current into first and second periodic control signals which are 180.degree. out of phase with respect to each other and which have equal magnitudes corresponding to the magnitude of the associated electrode current; and couplers for magnetically coupling individual ones of the first control signals and for magnetically coupling individual ones of the second signals such that the corresponding electrode currents are equalized or rendered proportional by balancing the same in the same or constant ratios in accordance with the locations of the electrode currents.

  11. Analytical investigation of critical phenomena in MHD power generators

    NASA Technical Reports Server (NTRS)

    1980-01-01

    Critical phenomena in the Arnold Engineering Development Center (AEDC) High Performance Demonstration Experiment (HPDE) and the U.S. U-25 Experiment, are analyzed. The performance of a NASA specified 500 MW(th) flow train is analyzed. Critical phenomena analyzed include: Hall voltage overshoots; optimal load schedules; parametric dependence of the electrode voltage drops; boundary layer behavior; near electrode phenomena with finite electrode segmentation; current distribution in the end regions; scale up rules; optimum Mach number distribution; and the effects of alternative cross sectional shapes.

  12. MHD Coal Fired Flow Facility. Quarterly technical progress report, July-September 1980

    SciTech Connect

    Altstatt, M. C.; Attig, R. C.; Brosnan, D. A.

    1980-11-01

    Significant activity, task status, planned research, testing, development, and conclusions for the Magnetohydrodynamics (MHD) Coal-Fired Flow Facility (CFFF) and the Energy Conversion Facility (ECF) are described. On Task 1, the first phase of the downstream quench system was completed. On Task 2, all three combustor sections were completed, hydrotested, ASME code stamped, and delivered to UTSI. The nozzle was also delivered. Fabrication of support stands and cooling water manifolds for the combustor and vitiation heater were completed, heat transfer and thermal stress analysis, along with design development, were conducted on the generator and radiant furnace and secondary combustor installation progressed as planned. Under Task 3 an Elemental Analyzer and Atomic Absorption Spectrophotometer/Graphite Furnace were received and installed, sites were prepared for two air monitoring stations, phytoplankton analysis began, and foliage and soil sampling was conducted using all study plots. Some 288 soil samples were combined to make 72 samples which were analyzed. Also, approval was granted to dispose of MHD flyash and slag at the Franklin County landfill. Task 4 effort consisted of completing all component test plans, and establishing the capability of displaying experimental data in graphical format. Under Task 7, a preliminary testing program for critical monitoring of the local current and voltage non-uniformities in the generator electrodes was outlined, electrode metal wear characteristics were documented, boron nitride/refrasil composite interelectrode sealing was improved, and several refractories for downstream MHD applications were evaluated with promising results.

  13. 40 CFR Appendix Vii to Part 268 - LDR Effective Dates of Surface Disposed Prohibited Hazardous Wastes

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Disposed Prohibited Hazardous Wastes VII Appendix VII to Part 268 Protection of Environment ENVIRONMENTAL... VII to Part 268—LDR Effective Dates of Surface Disposed Prohibited Hazardous Wastes Table 1—Effective... Land Disposal Restrictions for Contaminated Soil and Debris (CSD) Restricted hazardous waste in...

  14. 40 CFR Appendix Vii to Part 268 - LDR Effective Dates of Surface Disposed Prohibited Hazardous Wastes

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Disposed Prohibited Hazardous Wastes VII Appendix VII to Part 268 Protection of Environment ENVIRONMENTAL... VII to Part 268—LDR Effective Dates of Surface Disposed Prohibited Hazardous Wastes Table 1—Effective... Contaminated Soil and Debris (CSD) Restricted hazardous waste in CSD Effective date 1. Solvent-(F001-F005)...

  15. 78 FR 36011 - Region VII Regulatory Fairness Board; Federal Regulatory Enforcement Fairness Hearing

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-14

    ... ADMINISTRATION Region VII Regulatory Fairness Board; Federal Regulatory Enforcement Fairness Hearing AGENCY: U.S. Small Business Administration (SBA). ACTION: Notice of open meeting of the Regional (Region VII) Small... Region VII Regulatory Fairness Board must contact Jeanna Trenkamp by June 17, 2013 in writing, by fax...

  16. 40 CFR Appendix Vii to Part 268 - LDR Effective Dates of Surface Disposed Prohibited Hazardous Wastes

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... retorting, acid leaching followed by chemical precipitation, or thermal recovery of metals; as well as all... Disposed Prohibited Hazardous Wastes VII Appendix VII to Part 268 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SOLID WASTES (CONTINUED) LAND DISPOSAL RESTRICTIONS Pt. 268, App. VII...

  17. 40 CFR Appendix Vii to Part 268 - LDR Effective Dates of Surface Disposed Prohibited Hazardous Wastes

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 28 2013-07-01 2013-07-01 false LDR Effective Dates of Surface Disposed Prohibited Hazardous Wastes VII Appendix VII to Part 268 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SOLID WASTES (CONTINUED) LAND DISPOSAL RESTRICTIONS Pt. 268, App. VII...

  18. Gas Core Reactor Numerical Simulation Using a Coupled MHD-MCNP Model

    NASA Technical Reports Server (NTRS)

    Kazeminezhad, F.; Anghaie, S.

    2008-01-01

    Analysis is provided in this report of using two head-on magnetohydrodynamic (MHD) shocks to achieve supercritical nuclear fission in an axially elongated cylinder filled with UF4 gas as an energy source for deep space missions. The motivation for each aspect of the design is explained and supported by theory and numerical simulations. A subsequent report will provide detail on relevant experimental work to validate the concept. Here the focus is on the theory of and simulations for the proposed gas core reactor conceptual design from the onset of shock generations to the supercritical state achieved when the shocks collide. The MHD model is coupled to a standard nuclear code (MCNP) to observe the neutron flux and fission power attributed to the supercritical state brought about by the shock collisions. Throughout the modeling, realistic parameters are used for the initial ambient gaseous state and currents to ensure a resulting supercritical state upon shock collisions.

  19. Newtonian CAFE: a new ideal MHD code to study the solar atmosphere

    NASA Astrophysics Data System (ADS)

    González-Avilés, J. J.; Cruz-Osorio, A.; Lora-Clavijo, F. D.; Guzmán, F. S.

    2015-12-01

    We present a new code designed to solve the equations of classical ideal magnetohydrodynamics (MHD) in three dimensions, submitted to a constant gravitational field. The purpose of the code centres on the analysis of solar phenomena within the photosphere-corona region. We present 1D and 2D standard tests to demonstrate the quality of the numerical results obtained with our code. As solar tests we present the transverse oscillations of Alfvénic pulses in coronal loops using a 2.5D model, and as 3D tests we present the propagation of impulsively generated MHD-gravity waves and vortices in the solar atmosphere. The code is based on high-resolution shock-capturing methods, uses the Harten-Lax-van Leer-Einfeldt (HLLE) flux formula combined with Minmod, MC, and WENO5 reconstructors. The divergence free magnetic field constraint is controlled using the Flux Constrained Transport method.

  20. Flow aerodynamics modeling of an MHD swirl combustor - Calculations and experimental verification

    NASA Technical Reports Server (NTRS)

    Gupta, A. K.; Beer, J. M.; Louis, J. F.; Busnaina, A. A.; Lilley, D. G.

    1981-01-01

    The paper describes a computer code for calculating the flow dynamics of a constant-density flow in the second-stage trumpet shaped nozzle section of a two-stage MHD swirl combustor for application to a disk generator. The primitive pressure-velocity variable, finite-difference computer code has been developed for the computation of inert nonreacting turbulent swirling flows in an axisymmetric MHD model swirl combustor. The method and program involve a staggered grid system for axial and radial velocities, and a line relaxation technique for the efficient solution of the equations. The code produces as output the flow field map of the nondimensional stream function, axial and swirl velocity. It was found that the best location for seed injection to obtain a uniform distribution at the combustor exit is in the central location for seed injected at the entrance to the second stage combustor.

  1. FTE Dependence on IMF Orientation and Presence of Hall Physics in Global MHD Simulations

    NASA Astrophysics Data System (ADS)

    Maynard, K. M.; Germaschewski, K.; Lin, L.; Raeder, J.

    2013-12-01

    Flux Transfer Events (FTEs) are poleward traveling flux ropes that form in the dayside magnetopause and represent significant coupling of the solar wind to the magnetosphere during times of southward IMF. In the 35 years since their discovery, FTEs have been extensively observed and modeled; however, there is still no consensus on their generation mechanism. Previous modeling efforts have shown that FTE occurrence and size depend on the resistivity model that is used in simulations and the structure of X-lines in the magnetopause. We use Hall OpenGGCM, a global Hall-MHD code, to study the formation and propagation of FTEs in the dayside magnetopause using synthetic solar wind conditions. We examine large scale FTE structure and nearby magnetic separators for a range of IMF clock angles and dipole tilts. In addition, we investigate how FTE formation and recurrence rate depends on the presence of the Hall term in the generalized Ohm's law compared with resistive MHD.

  2. National Environmental/Energy Workforce Assessment for Region VII.

    ERIC Educational Resources Information Center

    National Field Research Center Inc., Iowa City, IA.

    This report represents a detailed summation of existing workforce levels, training programs, career potential, and staffing level projections through 1981 for EPA Region VII. This region serves the states of Iowa, Kansas, Missouri, and Nebraska. The specific pollution programs considered include air, noise, pesticides, potable water, radiation,…

  3. Title VII Program, Final Technical Report: 1985-86.

    ERIC Educational Resources Information Center

    Schuyler, Nancy B.; Yonan, Barbara

    This report documents the 1985-86 Title VII Program of the Austin (Texas) Independent School District. Major findings indicated the following: (1) three program components--staff training, tutoring, and curriculum development--were implemented as planned; (2) the staff training component included a series of English as a Second Language…

  4. Photosynthetic pigments of oceanic Chlorophyta belonging to prasinophytes clade VII.

    PubMed

    Lopes Dos Santos, Adriana; Gourvil, Priscillia; Rodríguez, Francisco; Garrido, José Luis; Vaulot, Daniel

    2016-02-01

    The ecological importance and diversity of pico/nanoplanktonic algae remains poorly studied in marine waters, in part because many are tiny and without distinctive morphological features. Amongst green algae, Mamiellophyceae such as Micromonas or Bathycoccus are dominant in coastal waters while prasinophytes clade VII, yet not formerly described, appear to be major players in open oceanic waters. The pigment composition of 14 strains representative of different subclades of clade VII was analyzed using a method that improves the separation of loroxanthin and neoxanthin. All the prasinophytes clade VII analyzed here showed a pigment composition similar to that previously reported for RCC287 corresponding to pigment group prasino-2A. However, we detected in addition astaxanthin for which it is the first report in prasinophytes. Among the strains analyzed, the pigment signature is qualitatively similar within subclades A and B. By contrast, RCC3402 from subclade C (Picocystis) lacks loroxanthin, astaxanthin, and antheraxanthin but contains alloxanthin, diatoxanthin, and monadoxanthin that are usually found in diatoms or cryptophytes. For subclades A and B, loroxanthin was lowest at highest light irradiance suggesting a light-harvesting role of this pigment in clade VII as in Tetraselmis.

  5. The RFP dynamo: MHD to kinetic regimes

    NASA Astrophysics Data System (ADS)

    Sarff, J. S.; Almagri, A. F.; den Hartog, D. J.; McCollam, K. J.; Nornberg, M. D.; Sauppe, J. P.; Sovinec, C. R.; Terry, P. W.; Triana, J. C.; Brower, D. L.; Ding, W. X.; Parke, E.

    2015-11-01

    The hallmark of magnetic relaxation in an RFP plasma is profile flattening of J0 .B0 /B2 effected by a dynamo-like emf in Ohm's law. This is well-studied in single-fluid MHD, but recent MST results and extended MHD modeling show that both and the Hall emf, - /ene , are important, revealing decoupled electron and ion motion. Since dynamo is current-related, the electron fluid emf, , captures both effects. In MST, the electron flow is dominantly Ve , 1 ~E1 ×B0 /B2 , implying ~ / B . This and the Hall emf are measured in MST for comparison in Ohm's law. A finite-pressure response is also possible, e.g., ``diamagnetic dynamo'', ∇ . /ene , associated with diamagnetic drift, and ``kinetic dynamo'' associated with collisionless streaming of electrons in a stochastic magnetic field. Correlation measurements and using FIR interferometry and Thomson scattering reveal these as small but finite in MST. A kinetic emf might be expected for any high-beta plasma with inhomogeneous pressure. Support by DOE/NSF.

  6. 3D Hall MHD Reconnection Dynamics

    NASA Astrophysics Data System (ADS)

    Huba, J. D.; Rudakov, L.

    2002-05-01

    A 3D Hall MHD simulation code (VooDoo) has recently been developed at the Naval Research Laboratory. We present preliminary results of a fully 3D magnetic reconnection study using this code. The initial configuration of the plasma system is as follows. The ambient, reversed magnetic field is in the x-direction and is proportional to B0 tanh(y/Ly) where Ly is the scale length of the current sheet. Perturbation fields δ Bx and δ By are introduced to initiate the reconnection process. This initial configuration is similar to that used in the 2D GEM reconnection study. However, the perturbation fields are localized in the z-direction. We consider two cases: no guide field (Bz = 0) and a weak guide field (Bz = 0.1B0). We find that the reconnection process is not stationary in the z-direction but propagates in the B x ∇ n direction consistent with Hall drift physics. Hence, an asymmetric disruption of the current sheet ensues. The flow structure of the plasma in the vicinity of the X-point is complex. We find that the `neutral line' (i.e, along the z-direction) is not an ignorable coordinate and is not periodic in Hall MHD reconnection dynamics; two assumptions that are often made in reconnection studies. \\ Research supported by NASA and ONR

  7. Solar wind turbulence: Observations of MHD effects

    NASA Technical Reports Server (NTRS)

    Bavassano, B.

    1995-01-01

    Since the first in-situ observations it was realized that the solar wind is permeated by large-amplitude variations on a very extended range of scales. In this paper an overview of our present state of knowledge for fluctuations in the magnetohydrodynamic (MHD) regime is given. These fluctuations are an important component of the solar wind variability and notably contribute to the overall energy and momentum flux. They generally have a turbulent character and their amplitude is large enough to suggest the presence of nonlinear effects. In recent years the use of high time-resolution data on an extended range of heliocentric distances has allowed major steps towards a satisfactory understanding of the solar wind MHD fluctuations. Their radial evolution in the expanding wind has been determined through detailed analyses of the variations in their spectral features. correlations. and anisotropics. The role of interplanetary sources has been carefully investigated. The influence of interactions with structures convected by the solar wind has been examined. Fluctuations have been studied in the light of theories developed to draw together the effects of both incompressibility and compressibility. Increasing attention has been devoted to the intermittent character of the turbulence. Finally, very recent observations by Ulysses at high heliographic latitudes have allowed the first in-situ analysis of turbulence features in polar regions of the heliosphere.

  8. Lattice Boltzmann Representations of MHD Turbulence

    NASA Astrophysics Data System (ADS)

    Vahala, George; Vahala, Linda; Soe, Min; Flint, Christopher

    2013-10-01

    Lattice Botlzmann algorithms are an ideally parallelized method for the solutions of macroscopic nonlinear equations of physics - like resistive MHD. In its simplest LB representation one introduces a scalar distribution for the density-velocity fields and a vector distribution for the magnetic field. An important feature is that gradients of certain macroscopic fields can be represented by local moments of the mesoscopic distribution functions. In particular, div B = 0 can be exactly enforced to machine accuracy, without any divergence cleaning. One of the problems facing the explicit LB code is numerical instabilities. Methods to permit strong turbulence simulations include: (a) moving from a single BGK to multiple collisional relaxation, (b) quasi-equilibria and central moment enhanced LB representations. The LB turbulence modeling of Ansumali et al. to Navier-Stokes turbulence will be extended to MHD in which in its noted that filtering and Chapman-Enskog limits do not commute. In the NS-case, it leads to unique Samgorinsky closure scheme, with definite filter width.

  9. ENDF/B-VII.1 Neutron Cross Section Data Testing with Critical Assembly Benchmarks and Reactor Experiments

    SciTech Connect

    Kahler, A.C.; Herman, M.; Kahler,A.C.; MacFarlane,R.E.; Mosteller,R.D.; Kiedrowski,B.C.; Frankle,S.C.; Chadwick,M.B.; McKnight,R.D.; Lell,R.M.; Palmiotti,G.; Hiruta,H.; Herman,M.; Arcilla,R.; Mughabghab,S.F.; Sublet,J.C.; Trkov,A.; Trumbull,T.H.; Dunn,M.

    2011-12-01

    The ENDF/B-VII.1 library is the latest revision to the United States Evaluated Nuclear Data File (ENDF). The ENDF library is currently in its seventh generation, with ENDF/B-VII.0 being released in 2006. This revision expands upon that library, including the addition of new evaluated files (was 393 neutron files previously, now 423 including replacement of elemental vanadium and zinc evaluations with isotopic evaluations) and extension or updating of many existing neutron data files. Complete details are provided in the companion paper [M. B. Chadwick et al., 'ENDF/B-VII.1 Nuclear Data for Science and Technology: Cross Sections, Covariances, Fission Product Yields and Decay Data,' Nuclear Data Sheets, 112, 2887 (2011)]. This paper focuses on how accurately application libraries may be expected to perform in criticality calculations with these data. Continuous energy cross section libraries, suitable for use with the MCNP Monte Carlo transport code, have been generated and applied to a suite of nearly one thousand critical benchmark assemblies defined in the International Criticality Safety Benchmark Evaluation Project's International Handbook of Evaluated Criticality Safety Benchmark Experiments. This suite covers uranium and plutonium fuel systems in a variety of forms such as metallic, oxide or solution, and under a variety of spectral conditions, including unmoderated (i.e., bare), metal reflected and water or other light element reflected. Assembly eigenvalues that were accurately predicted with ENDF/B-VII.0 cross sections such as unmoderated and uranium reflected {sup 235}U and {sup 239}Pu assemblies, HEU solution systems and LEU oxide lattice systems that mimic commercial PWR configurations continue to be accurately calculated with ENDF/B-VII.1 cross sections, and deficiencies in predicted eigenvalues for assemblies containing selected materials, including titanium, manganese, cadmium and tungsten are greatly reduced. Improvements are also confirmed for

  10. ENDF/B-VII.1 Neutron Cross Section Data Testing with Critical Assembly Benchmarks and Reactor Experiments

    NASA Astrophysics Data System (ADS)

    Kahler, A. C.; MacFarlane, R. E.; Mosteller, R. D.; Kiedrowski, B. C.; Frankle, S. C.; Chadwick, M. B.; McKnight, R. D.; Lell, R. M.; Palmiotti, G.; Hiruta, H.; Herman, M.; Arcilla, R.; Mughabghab, S. F.; Sublet, J. C.; Trkov, A.; Trumbull, T. H.; Dunn, M.

    2011-12-01

    The ENDF/B-VII.1 library is the latest revision to the United States' Evaluated Nuclear Data File (ENDF). The ENDF library is currently in its seventh generation, with ENDF/B-VII.0 being released in 2006. This revision expands upon that library, including the addition of new evaluated files (was 393 neutron files previously, now 423 including replacement of elemental vanadium and zinc evaluations with isotopic evaluations) and extension or updating of many existing neutron data files. Complete details are provided in the companion paper [M. B. Chadwick et al., "ENDF/B-VII.1 Nuclear Data for Science and Technology: Cross Sections, Covariances, Fission Product Yields and Decay Data," Nuclear Data Sheets, 112, 2887 (2011)]. This paper focuses on how accurately application libraries may be expected to perform in criticality calculations with these data. Continuous energy cross section libraries, suitable for use with the MCNP Monte Carlo transport code, have been generated and applied to a suite of nearly one thousand critical benchmark assemblies defined in the International Criticality Safety Benchmark Evaluation Project's International Handbook of Evaluated Criticality Safety Benchmark Experiments. This suite covers uranium and plutonium fuel systems in a variety of forms such as metallic, oxide or solution, and under a variety of spectral conditions, including unmoderated (i.e., bare), metal reflected and water or other light element reflected. Assembly eigenvalues that were accurately predicted with ENDF/B-VII.0 cross sections such as unmoderated and uranium reflected 235U and 239Pu assemblies, HEU solution systems and LEU oxide lattice systems that mimic commercial PWR configurations continue to be accurately calculated with ENDF/B-VII.1 cross sections, and deficiencies in predicted eigenvalues for assemblies containing selected materials, including titanium, manganese, cadmium and tungsten are greatly reduced. Improvements are also confirmed for selected

  11. Cloning of the canine beta-glucuronidase cDNA, mutation identification in canine MPS VII, and retroviral vector-mediated correction of MPS VII cells.

    PubMed

    Ray, J; Bouvet, A; DeSanto, C; Fyfe, J C; Xu, D; Wolfe, J H; Aguirre, G D; Patterson, D F; Haskins, M E; Henthorn, P S

    1998-03-01

    Mucopolysaccharidosis type VII (MPS VII) is an inherited disease resulting from deficient activity of the lysosomal acid hydrolase beta-glucuronidase (GUSB) and has been reported in humans, mice, cats, and dogs. To characterize canine MPS VII, we have isolated and sequenced the canine GUSB cDNA from normal and affected animals. A single nucleotide substitution was detected in the GUSB cDNA derived from MPS VII dogs. This guanosine to adenine base change at nucleotide position 559 in the canine cDNA sequence causes an arginine to histidine substitution at amino acid position 166. Introduction of the G to A substitution at position 559 in a mammalian expression vector containing the normal canine GUSB cDNA nearly eliminated the GUSB enzymatic activity, demonstrating that this mutation is the cause of canine MPS VII. A retroviral vector expressing the full-length canine beta-glucuronidase cDNA corrected the deficiency in MPS VII cells.

  12. The Mark 3 Haploscope

    NASA Technical Reports Server (NTRS)

    Decker, T. A.; Williams, R. E.; Kuether, C. L.; Logar, N. D.; Wyman-Cornsweet, D.

    1975-01-01

    A computer-operated binocular vision testing device was developed as one part of a system designed for NASA to evaluate the visual function of astronauts during spaceflight. This particular device, called the Mark 3 Haploscope, employs semi-automated psychophysical test procedures to measure visual acuity, stereopsis, phoria, fixation disparity, refractive state and accommodation/convergence relationships. Test procedures are self-administered and can be used repeatedly without subject memorization. The Haploscope was designed as one module of the complete NASA Vision Testing System. However, it is capable of stand-alone operation. Moreover, the compactness and portability of the Haploscope make possible its use in a broad variety of testing environments.

  13. Data Testing for ENDF/B-VII.1beta2

    SciTech Connect

    MacFarlane, Robert

    2011-01-01

    Calculations have been performed for 390 critical assemblies from the International Handbook of Evaluated Criticality Safety Benchmark Experiments using the beta2 release of ENDF/B-VII.1. The results are compared to previous results for ENDF/B-VII. Cases that changed between the two versions are highlighted, and the results are discussed. The Cross Section Evaluation Working Group (CSEWG) is working on a new release of the ENDF/B-VII library of evaluated nuclear data, and the 'beta2' set of files was recently made available by the National Nuclear Data Center (NNDC). A set of about 850 input files for the MCNP Monte Carlo code to run critical assemblies from the International Handbook of Evaluated Criticality Safety Benchmark Experiments was available from our previous data testing work for ENDF/B-VII.0. We have now run 390 of those cases using data based on the beta2 files, and those results will be presented below. The ENDF files were downloaded from the NNDC to a Mac workstation. They were then processed using NJOY10 into ACE format files for use in the MCNP Monte Carlo code. The processing was limited to materials needed for the data testing work at this point. The existing MCNP input decks were used. No checking was done to see if any of the benchmarks had been updated since the ENDF/B-VII testing was finished. Most runs used 50 million histories in order to get Monte Carlo statistical uncertainties down the 0.01% range.

  14. Observation of SOL Current Correlated with MHD Activity in NBI-heated DIII-D Tokamak Discharges

    SciTech Connect

    H. Takahashi; E.D. Fredrickson; M.J. Schaffer; M.E. Austin; T.E. Evans; L.L. Lao; J.G. Watkins

    2004-03-26

    This work investigates the potential roles played by the scrape-off-layer current (SOLC) in MHD activity of tokamak plasmas, including effects on stability. SOLCs are found during MHD activity that are: (1) slowly growing after a mode-locking-like event, (2) oscillating in the several kHz range and phase-locked with magnetic and electron temperature oscillations, (3) rapidly growing with a sub-ms time scale during a thermal collapse and a current quench, and (4) spiky in temporal behavior and correlated with spiky features in Da signals commonly identified with the edge localized mode (ELM). These SOLCs are found to be an integral part of the MHD activity, with a propensity to flow in a toroidally non-axisymmetric pattern and with magnitude potentially large enough to play a role in the MHD stability. Candidate mechanisms that can drive these SOLCs are identified: (a) toroidally non-axisymmetric thermoelectric potential, (b) electromotive force (EMF) from MHD activity, and (c) flux swing, both toroidal and poloidal, of the plasma column. An effect is found, stemming from the shear in the field line pitch angle, that mitigates the efficacy of a toroidally non-axisymmetric SOLC to generate a toroidally non-axisymmetric error field. Other potential magnetic consequences of the SOLC are identified: (i) its error field can introduce complications in feedback control schemes for stabilizing MHD activity and (ii) its toroidally non-axisymmetric field can be falsely identified as an axisymmetric field by the tokamak control logic and in equilibrium reconstruction. The radial profile of a SOLC observed during a quiescent discharge period is determined, and found to possess polarity reversals as a function of radial distance.

  15. Theoretical emission line ratios for [Fe III] and [Fe VII] applicable to the optical and infrared spectra of gaseous nebulae.

    PubMed

    Keenan, F P; Aller, L H; Ryans, R S; Hyung, S

    2001-08-14

    Recent calculations of electron impact excitation rates and Einstein A-coefficients for transitions among the 3d(6) levels of Fe III and among the 3d(2) levels of Fe VII are used to derive theoretical emission line ratios applicable to the optical and infrared spectra of gaseous nebulae. Results for [Fe III] are generated for electron temperatures T(e) = 7,000-20,000 K and densities N(e) = 10(2)-10(8) cm(-3), whereas those for [Fe VII] are provided for T(e) = 10,000-30,000 K and N(e) = 10(2)-10(8) cm(-3). The theoretical line ratios are significantly different in some instances from earlier calculations and resolve discrepancies between theory and observation found for the planetary nebulae IC 4997 and NGC 7027.

  16. Blood glucose may condition factor VII levels in diabetic and normal subjects.

    PubMed

    Ceriello, A; Giugliano, D; Quatraro, A; Dello Russo, P; Torella, R

    1988-12-01

    Increased factor VII levels have been reported in Type 1 (insulin-dependent) diabetic subjects. A direct correlation between fasting plasma glucose and factor VII level was found to exist in both diabetic and normal subjects. Induced-hyperglycaemia was able to increase factor VII levels in both diabetic patients and normal control subjects while, when euglycaemia was achieved in diabetic patients, factor VII values returned to normal range. This study shows that the level of factor VII may be directly conditioned by circulating blood glucose and, therefore, stresses the role of hyperglycaemia in conditioning coagulation abnormalities in diabetes mellitus.

  17. Mark Twain's Nemesis: The Paige Compositor.

    ERIC Educational Resources Information Center

    Goble, Corban

    Samuel Clemens (Mark Twain), who had set type by hand in his youth, had believed that a mechanical composer was beyond the realm of possibility. In 1880, however, he invested $2,000 in an early typesetter invented by James W. Paige. Both Clemens and Paige dreamed of immense wealth that would be generated by selling thousands of Paige Compositors.…

  18. MHD Augmentation of Rocket Engines Using Beamed Energy

    NASA Astrophysics Data System (ADS)

    Lineberry, John T.; Chapman, James N.; Litchford, Ron J.; Jones, Jonathan

    2003-05-01

    MHD technology and fundamental relations that pertain to accelerating a working fluid for propulsion of space vehicles are reviewed. Previous concepts on MHD propulsion have considered use of an on-board power supply to provide the electric power for the MHD thruster which is accompanied by an obvious weight penalty. In this study, an orbiting power station that beams microwave or laser power to the spacecraft is considered which eliminates this penalty making the thruster significantly more effective from the thrust-to-weight viewpoint. The objective of the study was to investigate augmenting a rocket motor to increase the ISP into the 2,500 seconds range using MHD acceleration. Mission scenarios are presented to parametrically compare the MHD augmented motor. Accelerator performance is calculated for an array of cases which vary the mass throughput, magnetic field strength and MHD interaction level. Performance improved with size, magnetic field strength and interaction level, although lower interaction levels can also produce attractive configurations. Accelerator efficiencies are typically 80-90%. The results display a large regime for improved performance in which the extent of the regime is critically dependent upon the weight of the power receiving equipment (rectenna). It is concluded that this system has potential when used with an orbiting power station that transmits power to the space vehicle by microwave radiation or laser beams. The most critical technology improvement needed is a reduced weight rectenna system but more development is also needed on the MHD accelerator, which is currently underway with NASA sponsorship.

  19. Revisiting MHD stability comparison theorems: Some surprising new results

    NASA Astrophysics Data System (ADS)

    Cerfon, Antoine; Freidberg, Jeffrey

    2009-05-01

    The classic MHD stability comparison theorems (Kruskal-Oberman, Rosenbluth-Rostoker) show that ideal MHD yields the most stringent stability limits according to the hierarchy δWCGL>δWKIN>δWMHD. This has long justified the use of ideal MHD for conservative predictions of MHD stability boundaries. We reexamine these theorems, with the following conclusions:(1) It is crucial to distinguish between ergodic and closed field line systems.(2) It is essential to account for resonant particles in the kinetic MHD model.(3) For ergodic systems the original kinetic MHD analysis over-estimates stability: δWKIN>δWMHD. Our new result predicts δWKIN=δWMHD.(4) For closed line systems plasma compressibility effects become important, and resonant particle effects vanish. Both the original and new analysis predict δWKIN>δWMHD. However, using a Vlasov-Fluid model with Vlasov ions and fluid electrons we show that both δWKIN and δWMHD, while mathematically correct, yield the wrong physical result. The V-F model shows that at marginal stability the compressibility stabilization term vanishes identically! For ergodic systems, marginal stability is always incompressible, so δWKIN=δWMHD=δWVF. For compressible modes in closed line systems, however, perpendicular resonant particle effects cancel the stabilizing effect of plasma compressibility predicted by ideal and kinetic MHD: δWKIN>δWMHD>δWVF.

  20. Extended-MHD modeling of diamagnetic-drift tearing instabilities

    NASA Astrophysics Data System (ADS)

    King, Jacob; Kruger, Scott

    2012-03-01

    We use analytics and computations with the NIMROD code to examine tearing stability in large-guide-field slab cases with a nonzero equilibrium pressure gradient. A well known result from drift-reduced MHD is the diamagnetic drift associated with the pressure gradient has a stabilizing influence were the dispersion relation becomes (γ+iφ*e)^3γ(γ+iφ*i)=γrMHD^5 [1]. Here φ*i and φ*e are the ion- and electron-diamagnetic frequencies and γrMHD is the tearing growth rate with a resistive-MHD model. Preliminary computational results with an unreduced extended-MHD model do not produce the expected drift-reduced result. For moderate values of φ*i (φ*i<=3γrMHD), the computations follow the dispersion relation that would result if the ∇pe term were not included in the drift-reduced parallel Ohm's law: (γ+iφ*e)^4(γ+iφ*i)=γrMHD^5. Analytics, guided by computational diagnostics, are used to examine the significant terms in the flux evolution equation and investigate the discrepancy with the drift-reduced result.[4pt] [1] For example Coppi, PoF 7, 1501 (1964); Biskamp, NF 18, 1059 (1978).

  1. Broken Symmetry and Coherent Structure in MHD Turbulence

    NASA Technical Reports Server (NTRS)

    Shebalin, John V.

    2007-01-01

    Absolute equilibrium ensemble theory for ideal homogeneous magnetohydrodynamic (MHD) turbulence is fairly well developed. Theory and Simulation indicate that ideal MHD turbulence non-ergodic and contains coherent structure. The question of applicability real (i.e., dissipative) MHD turbulence is examined. Results from several very long time numerical simulations on a 64(exp 3) grid are presented. It is seen that coherent structure begins to form before decay dominates over nonlinearity. The connection with inverse spectral cascades and selective decay will also be discussed.

  2. A summary of the ECAS MHD power plant results

    NASA Technical Reports Server (NTRS)

    Seikel, G. R.; Harris, L. P.

    1976-01-01

    The performance and the cost of electricity (COE) for MHD systems utilizing coal or coal derived fuels are summarized along with a conceptual open cycle MHD plant design. The results show that open cycle coal fired recuperatively preheated MHD systems have potentially one of the highest coal-pile-to-bus bar efficiencies (48.3%) and also one of the lowest COE of the systems studied. Closed cycle, inert gas systems do not appear to have the potential of exceeding the efficiency of or competing with the COE of advanced steam plants.

  3. Scalable implicit incompressible resistive MHD with stabilized FE and fully-coupled Newton–Krylov-AMG

    SciTech Connect

    Shadid, J. N.; Pawlowski, R. P.; Cyr, E. C.; Tuminaro, R. S.; Chacon, L.; Weber, P. D.

    2016-02-10

    Here, we discuss that the computational solution of the governing balance equations for mass, momentum, heat transfer and magnetic induction for resistive magnetohydrodynamics (MHD) systems can be extremely challenging. These difficulties arise from both the strong nonlinear, nonsymmetric coupling of fluid and electromagnetic phenomena, as well as the significant range of time- and length-scales that the interactions of these physical mechanisms produce. This paper explores the development of a scalable, fully-implicit stabilized unstructured finite element (FE) capability for 3D incompressible resistive MHD. The discussion considers the development of a stabilized FE formulation in context of the variational multiscale (VMS) method, and describes the scalable implicit time integration and direct-to-steady-state solution capability. The nonlinear solver strategy employs Newton–Krylov methods, which are preconditioned using fully-coupled algebraic multilevel preconditioners. These preconditioners are shown to enable a robust, scalable and efficient solution approach for the large-scale sparse linear systems generated by the Newton linearization. Verification results demonstrate the expected order-of-accuracy for the stabilized FE discretization. The approach is tested on a variety of prototype problems, that include MHD duct flows, an unstable hydromagnetic Kelvin–Helmholtz shear layer, and a 3D island coalescence problem used to model magnetic reconnection. Initial results that explore the scaling of the solution methods are also presented on up to 128K processors for problems with up to 1.8B unknowns on a CrayXK7.

  4. Interplanetary shock-bow shock interaction: Comparison of a global MHD model and observation

    NASA Astrophysics Data System (ADS)

    Goncharov, O.; Šafránková, J.; Němeček, Z.

    2015-09-01

    A fast forward shock passing through the bow shock would generate a train of new discontinuities that differ with the distance from the Sun-Earth line. However, interplanetary (IP) shocks are often followed by a rotation of the interplanetary magnetic field (IMF) over a large angle and a presence of this rotation can modify the interaction process. The present paper analyzes in detail one IP shock where data measured by Wind are used as an input to a global BATS-R-US MHD model and the model prediction is compared with Geotail magnetosheath observations. The study is based on three runs of the global MHD model that use different modifications of upstream conditions. We have found that (1) about 45% of IP shocks is followed by a significant IMF rotation within 15 min after the shock ramp; (2) the IMF rotation modifies the dynamics of the magnetospheric response to the IP shock arrival; (3) a train of new discontinuities created by an interaction of the IP shock with bow shock can be identified in MHD simulations as well as in the experimental data; and (4) a new discontinuity is created by the interaction of the IMF rotation with the bow shock.

  5. JOINT INVERSE CASCADE OF MAGNETIC ENERGY AND MAGNETIC HELICITY IN MHD TURBULENCE

    SciTech Connect

    Stepanov, R.; Frick, P.; Mizeva, I.

    2015-01-10

    We show that oppositely directed fluxes of energy and magnetic helicity coexist in the inertial range in fully developed magnetohydrodynamic (MHD) turbulence with small-scale sources of magnetic helicity. Using a helical shell model of MHD turbulence, we study the high Reynolds number MHD turbulence for helicity injection at a scale that is much smaller than the scale of energy injection. In a short range of scales larger than the forcing scale of magnetic helicity, a bottleneck-like effect appears, which results in a local reduction of the spectral slope. The slope changes in a domain with a high level of relative magnetic helicity, which determines that part of the magnetic energy is related to the helical modes at a given scale. If the relative helicity approaches unity, the spectral slope tends to –3/2. We show that this energy pileup is caused by an inverse cascade of magnetic energy associated with the magnetic helicity. This negative energy flux is the contribution of the pure magnetic-to-magnetic energy transfer, which vanishes in the non-helical limit. In the context of astrophysical dynamos, our results indicate that a large-scale dynamo can be affected by the magnetic helicity generated at small scales. The kinetic helicity, in particular, is not involved in the process at all. An interesting finding is that an inverse cascade of magnetic energy can be provided by a small-scale source of magnetic helicity fluctuations without a mean injection of magnetic helicity.

  6. Exploring reconnection, current sheets, and dissipation in a laboratory MHD turbulence experiment

    NASA Astrophysics Data System (ADS)

    Schaffner, D. A.

    2015-12-01

    The Swarthmore Spheromak Experiment (SSX) can serve as a testbed for studying MHD turbulence in a controllable laboratory setting, and in particular, explore the phenomena of reconnection, current sheets and dissipation in MHD turbulence. Plasma with turbulently fluctuating magnetic and velocity fields can be generated using a plasma gun source and launched into a flux-conserving cylindrical tunnel. No background magnetic field is applied so internal fields are allowed to evolve dynamically. Point measurements of magnetic and velocity fluctuations yield broadband power-law spectra with a steepening breakpoint indicative of the onset of a dissipation scale. The frequency range at which this steepening occurs can be correlated to the ion inertial scale of the plasma, a length which is characteristic of the size of current sheets in MHD plasmas and suggests a connection to dissipation. Observation of non-Gaussian intermittent jumps in magnetic field magnitude and angle along with measurements of ion temperature bursts suggests the presence of current sheets embedded within the turbulent plasma, and possibly even active reconnection sites. Additionally, structure function analysis coupled with appeals to fractal scaling models support the hypothesis that current sheets are associated with dissipation in this system.

  7. Laser-Plasma Modeling Using PERSEUS Extended-MHD Simulation Code for HED Plasmas

    NASA Astrophysics Data System (ADS)

    Hamlin, Nathaniel; Seyler, Charles

    2016-10-01

    We discuss the use of the PERSEUS extended-MHD simulation code for high-energy-density (HED) plasmas in modeling laser-plasma interactions in relativistic and nonrelativistic regimes. By formulating the fluid equations as a relaxation system in which the current is semi-implicitly time-advanced using the Generalized Ohm's Law, PERSEUS enables modeling of two-fluid phenomena in dense plasmas without the need to resolve the smallest electron length and time scales. For relativistic and nonrelativistic laser-target interactions, we have validated a cycle-averaged absorption (CAA) laser driver model against the direct approach of driving the electromagnetic fields. The CAA model refers to driving the radiation energy and flux rather than the fields, and using hyperbolic radiative transport, coupled to the plasma equations via energy source terms, to model absorption and propagation of the radiation. CAA has the advantage of not requiring adequate grid resolution of each laser wavelength, so that the system can span many wavelengths without requiring prohibitive CPU time. For several laser-target problems, we compare existing MHD results to extended-MHD results generated using PERSEUS with the CAA model, and examine effects arising from Hall physics. This work is supported by the National Nuclear Security Administration stewardship sciences academic program under Department of Energy cooperative agreements DE-FOA-0001153 and DE-NA0001836.

  8. Forensic surface metrology: tool mark evidence.

    PubMed

    Gambino, Carol; McLaughlin, Patrick; Kuo, Loretta; Kammerman, Frani; Shenkin, Peter; Diaczuk, Peter; Petraco, Nicholas; Hamby, James; Petraco, Nicholas D K

    2011-01-01

    Over the last several decades, forensic examiners of impression evidence have come under scrutiny in the courtroom due to analysis methods that rely heavily on subjective morphological comparisons. Currently, there is no universally accepted system that generates numerical data to independently corroborate visual comparisons. Our research attempts to develop such a system for tool mark evidence, proposing a methodology that objectively evaluates the association of striated tool marks with the tools that generated them. In our study, 58 primer shear marks on 9 mm cartridge cases, fired from four Glock model 19 pistols, were collected using high-resolution white light confocal microscopy. The resulting three-dimensional surface topographies were filtered to extract all "waviness surfaces"-the essential "line" information that firearm and tool mark examiners view under a microscope. Extracted waviness profiles were processed with principal component analysis (PCA) for dimension reduction. Support vector machines (SVM) were used to make the profile-gun associations, and conformal prediction theory (CPT) for establishing confidence levels. At the 95% confidence level, CPT coupled with PCA-SVM yielded an empirical error rate of 3.5%. Complementary, bootstrap-based computations for estimated error rates were 0%, indicating that the error rate for the algorithmic procedure is likely to remain low on larger data sets. Finally, suggestions are made for practical courtroom application of CPT for assigning levels of confidence to SVM identifications of tool marks recorded with confocal microscopy.

  9. ENDF/B-VII Nuclear Data Libraries for SCALE-6.0

    SciTech Connect

    Williams, Mark L; Ilas, Germina

    2009-01-01

    Version 6 of the SCALE (Standardized Computer Analyses for Licensing Evaluation) code system was released in February 2009. SCALE provides a comprehensive, integrated package of modular programs and nuclear data for a wide range of applications, including reactor physics, criticality safety, shielding, sensitivity/uncertainty analysis, and isotopic transmutation and radiation source term determination. SCALE computational modules are executed by automated control sequences that prepare input and call the desired modules in a particular order, linking output from one calculation to the next in series. The SCALE lattice physics sequence TRITON generates few-group, assembly-homogenized cross sections, as a function of burnup and branch states, which can be input to core simulator codes. TRITON couples the ORIGEN-S depletion module with either the NEWT (NEW Transport algorithm) two-dimensional (2D) arbitrary-geometry transport code or the three-dimensional Monte Carlo KENO code. Fluxes from the transport solution, along with self-shielded multigroup (MG) cross sections, are passed to ORIGEN-S, which computes the time-dependent isotopic concentrations of more than 1400 nuclides. One of the major advancements in SCALE 6 is the availability of new nuclear data libraries based on ENDF/B-VII for neutron transport calculations. In this paper we describe the SCALE ENDF/B-VII (designated here as V7) libraries and present some validation results for critical benchmarks and isotopic depletion experiments.

  10. 2 CFR Appendix Vii to Part 200 - States and Local Government and Indian Tribe Indirect Cost Proposals

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... Indirect Cost Proposals VII Appendix VII to Part 200 Grants and Agreements Office of Management and Budget Guidance for Grants and Agreements OFFICE OF MANAGEMENT AND BUDGET GUIDANCE Reserved UNIFORM ADMINISTRATIVE REQUIREMENTS, COST PRINCIPLES, AND AUDIT REQUIREMENTS FOR FEDERAL AWARDS Pt. 200, App. VII Appendix VII to...

  11. A helically distorted MHD flux rope model

    NASA Technical Reports Server (NTRS)

    Theobald, Michael L.; Montgomery, David

    1990-01-01

    A flux rope model is proposed which has a variable degree of helical distortion from axisymmetry. The basis for this suggestion is a series of numerical and analytical investigations of magnetohydrodynamic states which result when an axial electric current is directed down on dc magnetic field. The helically distorted states involve a flow velocity and seem to be favored because of their lower rate of energy dissipation. Emphasis is on the magnetometer and particle energy analyzer traces that might be characteristic of such flux ropes. It is shown that even a fractionally small helical distortion may considerably alter the traces in minimum-variance coordinates. In short, what may be fairly common MHD processes can render a flux rope almost unrecognizable under standard diagnostics, even if the departures from axisymmetry are not great.

  12. Global MHD Models of the Solar Corona

    NASA Technical Reports Server (NTRS)

    Suess, S. T.; Rose, Franklin (Technical Monitor)

    2001-01-01

    Global magnetohydrodynamic (MHD) models of the solar corona are computationally intensive, numerically complex simulations that have produced important new results over the past few years. After a brief overview of how these models usually work, I will address three topics: (1) How these models are now routinely used to predict the morphology of the corona and analyze Earth and space-based remote observations of the Sun; (2) The direct application of these models to the analysis of physical processes in the corona and chromosphere and to the interpretation of in situ solar wind observations; and (3) The use of results from global models to validate the approximations used to make detailed studies of physical processes in the corona that are not otherwise possible using the global models themselves.

  13. Drag reduction in turbulent MHD pipe flows

    NASA Technical Reports Server (NTRS)

    Orlandi, P.

    1996-01-01

    This is a preliminary study devoted to verifying whether or not direct simulations of turbulent Magneto-Hydro-Dynamic (MHD) flows in liquid metals reproduce experimental observations of drag reduction. Two different cases have been simulated by a finite difference scheme which is second order accurate in space and time. In the first case, an external azimuthal magnetic field is imposed. In this case, the magnetic field acts on the mean axial velocity and complete laminarization of the flow at N(sub a) = 30 has been achieved. In the second case, an axial magnetic field is imposed which affects only fluctuating velocities, and thus the action is less efficient. This second case is more practical, but comparison between numerical and experimental results is only qualitative.

  14. Numerical linearized MHD model of flapping oscillations

    NASA Astrophysics Data System (ADS)

    Korovinskiy, D. B.; Ivanov, I. B.; Semenov, V. S.; Erkaev, N. V.; Kiehas, S. A.

    2016-06-01

    Kink-like magnetotail flapping oscillations in a Harris-like current sheet with earthward growing normal magnetic field component Bz are studied by means of time-dependent 2D linearized MHD numerical simulations. The dispersion relation and two-dimensional eigenfunctions are obtained. The results are compared with analytical estimates of the double-gradient model, which are found to be reliable for configurations with small Bz up to values ˜ 0.05 of the lobe magnetic field. Coupled with previous results, present simulations confirm that the earthward/tailward growth direction of the Bz component acts as a switch between stable/unstable regimes of the flapping mode, while the mode dispersion curve is the same in both cases. It is confirmed that flapping oscillations may be triggered by a simple Gaussian initial perturbation of the Vz velocity.

  15. Observational Tests of Recent MHD Turbulence Perspectives

    NASA Astrophysics Data System (ADS)

    Ghosh, Sanjoy

    2001-06-01

    This grant seeks to analyze the Heliospheric Missions data to test current theories on the angular dependence (with respect to mean magnetic field direction) of magnetohydrodynamic (MHD) turbulence in the solar wind. Solar wind turbulence may be composed of two or more dynamically independent components. Such components include magnetic pressure-balanced structures, velocity shears, quasi-2D turbulence, and slab (Alfven) waves. We use a method, developed during the first two years of this grant, for extracting the individual reduced spectra of up to three separate turbulence components from a single spacecraft time series. The method has been used on ISEE-3 data, Pioneer Venus Orbiter, Ulysses, and Voyager data samples. The correlation of fluctuations as a function of angle between flow direction and magnetic-field direction is the focus of study during the third year.

  16. Observational Tests of Recent MHD Turbulence Perspectives

    NASA Technical Reports Server (NTRS)

    Ghosh, Sanjoy; Guhathakurta, M. (Technical Monitor)

    2001-01-01

    This grant seeks to analyze the Heliospheric Missions data to test current theories on the angular dependence (with respect to mean magnetic field direction) of magnetohydrodynamic (MHD) turbulence in the solar wind. Solar wind turbulence may be composed of two or more dynamically independent components. Such components include magnetic pressure-balanced structures, velocity shears, quasi-2D turbulence, and slab (Alfven) waves. We use a method, developed during the first two years of this grant, for extracting the individual reduced spectra of up to three separate turbulence components from a single spacecraft time series. The method has been used on ISEE-3 data, Pioneer Venus Orbiter, Ulysses, and Voyager data samples. The correlation of fluctuations as a function of angle between flow direction and magnetic-field direction is the focus of study during the third year.

  17. MHD simulation of the Bastille day event

    NASA Astrophysics Data System (ADS)

    Linker, Jon; Torok, Tibor; Downs, Cooper; Lionello, Roberto; Titov, Viacheslav; Caplan, Ronald M.; Mikić, Zoran; Riley, Pete

    2016-03-01

    We describe a time-dependent, thermodynamic, three-dimensional MHD simulation of the July 14, 2000 coronal mass ejection (CME) and flare. The simulation starts with a background corona developed using an MDI-derived magnetic map for the boundary condition. Flux ropes using the modified Titov-Demoulin (TDm) model are used to energize the pre-event active region, which is then destabilized by photospheric flows that cancel flux near the polarity inversion line. More than 1033 ergs are impulsively released in the simulated eruption, driving a CME at 1500 km/s, close to the observed speed of 1700km/s. The post-flare emission in the simulation is morphologically similar to the observed post-flare loops. The resulting flux rope that propagates to 1 AU is similar in character to the flux rope observed at 1 AU, but the simulated ICME center passes 15° north of Earth.

  18. General Relativistic MHD Simulations of Jet Formation

    NASA Technical Reports Server (NTRS)

    Mizuno, Y.; Nishikawa, K.-I.; Hardee, P.; Koide, S.; Fishman, G. J.

    2005-01-01

    We have performed 3-dimensional general relativistic magnetohydrodynamic (GRMHD) simulations of jet formation from an accretion disk with/without initial perturbation around a rotating black hole. We input a sinusoidal perturbation (m = 5 mode) in the rotation velocity of the accretion disk. The simulation results show the formation of a relativistic jet from the accretion disk. Although the initial perturbation becomes weakened by the coupling among different modes, it survives and triggers lower modes. As a result, complex non-axisymmetric density structure develops in the disk and the jet. Newtonian MHD simulations of jet formation with a non-axisymmetric mode show the growth of the m = 2 mode but GRMHD simulations cannot see the clear growth of the m = 2 mode.

  19. Optical diagnostic measurements of coal-slag parameters in combustion MHD systems

    SciTech Connect

    Ariessohn, P.C.

    1980-08-01

    Hydrodynamic models have been developed to predict the behavior of slag layers on MHD generator walls and these have indicated a strong dependence of slag layer thickness on a number of system parameters. The first objective of this thesis was the development of a diagnostic technique capable of making continuous, in-situ measurements of the slag layer thickness, and the application of this technique in an MHD system for comparison with the predictions of one of the existing hydrodynamic models. The second objective of this thesis was the development of a diagnostic technique capable of making in-situ measurements of ash droplet size and concentration at the exit of an MHD combustor, and the study of the sensitivity of these quantities to various combustion parameters. A slag layer surface position monitor employing a laser triangulation method has been developed and used to measure variations in slag layer thickness as a function of substrate temperature for a variety of ash loadings and total reactant flowrates. Slag layer thickness is seen to decrease with increasing substrate temperature and plasma velocity. The measurement of mean size and concentration of suspended ash droplets in the plasma exiting the M-8 combustor has been accomplished utilizing a two-wavelength transmissometer developed for this purpose. This instrument incorporates several unique features which were required to overcome the difficulties imposed by the MHD environment. Measurements obtained with this device show that mean ash droplet diameter is relatively independent of ash loading, combustor residence time and combustion stoichiometry, but is a decreasing function of plasma temperature.

  20. A Two-Fluid, MHD Coronal Model

    NASA Technical Reports Server (NTRS)

    Suess, S. T.; Wang, A.-H.; Wu, S. T.; Poletto, G.; McComas, D. J.

    1999-01-01

    We describe first results from a numerical two-fluid MHD model of the global structure of the solar Corona. The model is two-fluid in the sense that it accounts for the collisional energy exchange between protons and electrons. As in our single-fluid model, volumetric heat and Momentum sources are required to produce high speed wind from Corona] holes, low speed wind above streamers, and mass fluxes similar to the empirical solar wind. By specifying different proton and electron heating functions we obtain a high proton temperature in the coronal hole and a relatively low proton temperature above the streamer (in comparison with the electron temperature). This is consistent with inferences from SOHO/UltraViolet Coronagraph Spectrometer instrument (UVCS), and with the Ulysses/Solar Wind Observations Over the Poles of the Sun instrument (SWOOPS) proton and electron temperature measurements which we show from the fast latitude scan. The density in the coronal hole between 2 and 5 solar radii (2 and 5 R(sub S)) is similar to the density reported from SPARTAN 201.-01 measurements by Fisher and Guhathakurta [19941. The proton mass flux scaled to 1 AU is 2.4 x 10(exp 8)/sq cm s, which is consistent with Ulysses observations. Inside the closed field region, the density is sufficiently high so that the simulation gives equal proton and electron temperatures due to the high collision rate. In open field regions (in the coronal hole and above the streamer) the proton and electron temperatures differ by varying amounts. In the streamer the temperature and density are similar to those reported empirically by Li et al. [1998], and the plasma beta is larger than unity everywhere above approx. 1.5 R(sub S), as it is in all other MHD coronal streamer models [e.g., Steinolfson et al., 1982; also G. A. Gary and D. Alexander, Constructing the coronal magnetic field, submitted to Solar Physics, 1998].

  1. A Two-Fluid, MHD Coronal Model

    NASA Technical Reports Server (NTRS)

    Suess, Steven T.; Wang, A.-H.; Wu, S. T.; Poletto, G.; McComas, D. J.

    1998-01-01

    We describe first results from a numerical two-fluid MHD model of the global structure of the solar corona. The model is two-fluid in the sense that it accounts for the collisional energy exchange between protons and electrons. As in our single-fluid model, volumetric heat and momentum sources are required to produce high speed wind from coronal holes, low speed wind above streamers, and mass fluxes similar to the empirical solar wind. By specifying different proton and electron heating functions we obtain a high proton temperature in the coronal hole and a relatively low proton temperature in the streamer (in comparison with the electron temperature). This is consistent with inferences from SOHO/UVCS, and with the Ulysses/SWOOPS proton and electron temperature measurements which we show from the fast latitude scan. The density in the coronal hole between 2 solar radii and 5 solar radii (2RS and 5RS) is similar to the density reported from SPARTAN 201-01 measurements by Fisher and Guhathakurta. The proton mass flux scaled to 1 AU is 2.4 x 10(exp 8)/sq cm s, which is consistent with Ulysses observations. Inside the closed field region, the density is sufficiently high so that the simulation gives equal proton and electron temperatures due to the high collision rate. In open field regions (in the coronal hole and above the streamer) the proton and electron temperatures differ by varying amounts. In the streamer, the temperature and density are similar to those reported empirically by Li et al and the plasma beta is larger than unity everywhere above approx. 1.5 R(sub s), as it is in all other MHD coronal streamer models.

  2. Magnetohydrodynamic generator scaling analysis for baseload commercial powerplants

    NASA Astrophysics Data System (ADS)

    Swallom, D. W.; Pian, C. C. P.

    1983-08-01

    MHD generator channel scaling analyses have been performed to definitize the effect of generator size and oxygen enrichment on channel performance. These studies have shown that MHD generator channels can be designed to operate efficiently over the range of 250 to 2135 thermal megawatts. The optimum design conditions for each of the thermal inputs were established by investigating various combinations of electrical load parameters, pressure ratios, magnetic field profiles, and channel lengths. These results provide design flexibility for the baseload combined cycle MHD/steam power plant.

  3. Diagnostic development and support of MHD (magnetohydrodynamics) test facilities

    SciTech Connect

    Not Available

    1989-07-01

    Mississippi State University (MSU) is developing diagnostic instruments for Magnetohydrodynamics (MHD) power train data acquisition and for support of MHD component development test facilities. Microprocessor-controlled optical instruments, initially developed for HRSR support, are being refined, and new systems to measure temperatures and gas-seed-slag stream characteristics are being developed. To further data acquisition and analysis capabilities, the diagnostic systems are being interfaced with MHD Energy Center computers. Technical support for the diagnostic needs of the national MHD research effort is being provided. MSU personnel will also cooperate with government agencies and private industries to improve the transformation of research and development results into processes, products and services applicable to their needs.

  4. TRANSITION FROM KINETIC TO MHD BEHAVIOR IN A COLLISIONLESS PLASMA

    SciTech Connect

    Parashar, Tulasi N.; Matthaeus, William H.; Shay, Michael A.; Wan, Minping

    2015-10-01

    The study of kinetic effects in heliospheric plasmas requires representation of dynamics at sub-proton scales, but in most cases the system is driven by magnetohydrodynamic (MHD) activity at larger scales. The latter requirement challenges available computational resources, which raises the question of how large such a system must be to exhibit MHD traits at large scales while kinetic behavior is accurately represented at small scales. Here we study this implied transition from kinetic to MHD-like behavior using particle-in-cell (PIC) simulations, initialized using an Orszag–Tang Vortex. The PIC code treats protons, as well as electrons, kinetically, and we address the question of interest by examining several different indicators of MHD-like behavior.

  5. Transition from Kinetic to MHD Behavior in a Collisionless Plasma

    NASA Astrophysics Data System (ADS)

    Parashar, Tulasi N.; Matthaeus, William H.; Shay, Michael A.; Wan, Minping

    2015-10-01

    The study of kinetic effects in heliospheric plasmas requires representation of dynamics at sub-proton scales, but in most cases the system is driven by magnetohydrodynamic (MHD) activity at larger scales. The latter requirement challenges available computational resources, which raises the question of how large such a system must be to exhibit MHD traits at large scales while kinetic behavior is accurately represented at small scales. Here we study this implied transition from kinetic to MHD-like behavior using particle-in-cell (PIC) simulations, initialized using an Orszag-Tang Vortex. The PIC code treats protons, as well as electrons, kinetically, and we address the question of interest by examining several different indicators of MHD-like behavior.

  6. Behavior of Np(VII, VI, V) in Silicate Solutions

    SciTech Connect

    Shilov, V P.; Fedoseev, A M.; Yusov, A B.; Delegard, Calvin H.

    2004-11-30

    Spectrophotometric methods were used to investigate the properties of neptunium(VII), (VI), and (V) in silicate solution. The transition of cationic neptunium(VII) to anionic species in non-complexing environments proceeds in the range of ?? 5.5 to 7.5. In the presence of carbonate, this transition occurs at ?? 10.0 to 11.5 and in silicate solutions at ?? 10.5-12.0. These findings show that cationic neptunium(VII) forms complexes with both carbonate and silicate and that the silicate complex is stronger than that of the carbonate. The competition of complex formation reactions for neptunium(VI) with carbonate and silicate and on the known complex stability constant of NpO2(CO3)34- allowed the NpO2SiO3 complex stability constant, log ? = 16.5, to be estimated. Determination of the formation constant of Np(V) complexes with SiO32- was not possible using similar methods.

  7. Water excitation MPRAGE MRI of VII and VIII cranial nerves

    SciTech Connect

    Litt, A.W.; Licata, P.; Knopp, E.A.; Thomasson, D.M.

    1996-03-01

    Our goal was to compare magnetization prepared rapid gradient echo-water excitation (MPR-AGE-WE) with conventional spin echo (CSE) in the evaluation of the VII and VIII cranial nerves. One hundred three consecutive patients with symptoms referable to the VII/VIII nerves were studied with CSE T1 and MPRAGE-WE following intravenous gadolinium, contrast agent. Each right and left nerve pair was independently evaluated for the presence of an enhancing mass and for visualization of the nerves. On the CSE images, 26 definite and 2 possible lesions were identified, whereas 28 definite and 2 possible abnormalities were seen on the MPRAGE-WE. Four cases were better identified on the MPRAGE-WE and one better seen on the CSE. This difference was not statistically significant (p = 0. 19). CSE demonstrated the nerves partially in 23 instances and completely in 6; MPRAGE-WE showed the nerves partially in 35 and completely in 73. This was highly significant (p < 0.001). With equivalent or slightly improved lesion detection and better visualization of the nerves, MPRAGE-WE may replace CSE in studying the VII/VIII nerves. 14 refs., 7 figs., 3 tabs.

  8. CROSS SECTION EVALUATIONS FOR ENDF/B-VII.

    SciTech Connect

    HERMAN, M.; ROCHMAN, D.; OBLOZINSKY, P.

    2006-06-05

    This is the final report of the work performed under the LANL contract on neutron cross section evaluations for ENDF/B-VII (April 2005-May 2006). The purpose of the contract was to ensure seamless integration of the LANL neutron cross section evaluations in the new ENDF/B-VII library. The following work was performed: (1) LANL evaluated data files submitted for inclusion in ENDF/B-VII were checked and, when necessary, formal formatting errors were corrected. As a consequence, ENDF checking codes, run on all LANL files, do not report any errors that would rise concern. (2) LANL dosimetry evaluations for {sup 191}Ir and {sup 193}Ir were completed to match ENDF requirements for the general purpose library suitable for transport calculations. A set of covariances for both isotopes is included in the ENDF files. (3) Library of fission products was assembled and successfully tested with ENDF checking codes, processed with NJOY-99.125 and simple MCNP calculations. (4) KALMAN code has been integrated with the EMPIRE system to allow estimation of covariances based on the combination of measurements and model calculations. Covariances were produced for 155,157-Gd and also for 6 remaining isotopes of Gd.

  9. Investigation of inconsistent ENDF/B-VII.1 independent and cumulative fission product yields with proposed revisions

    SciTech Connect

    Pigni, Marco T; Francis, Matthew W; Gauld, Ian C

    2015-01-01

    A recent implementation of ENDF/B-VII. independent fission product yields and nuclear decay data identified inconsistencies in the data caused by the use of updated nuclear scheme in the decay sub-library that is not reflected in legacy fission product yield data. Recent changes in the decay data sub-library, particularly the delayed neutron branching fractions, result in calculated fission product concentrations that are incompatible with the cumulative fission yields in the library, and also with experimental measurements. A comprehensive set of independent fission product yields was generated for thermal and fission spectrum neutron induced fission for 235,238U and 239,241Pu in order to provide a preliminary assessment of the updated fission product yield data consistency. These updated independent fission product yields were utilized in the ORIGEN code to evaluate the calculated fission product inventories with experimentally measured inventories, with particular attention given to the noble gases. An important outcome of this work is the development of fission product yield covariance data necessary for fission product uncertainty quantification. The evaluation methodology combines a sequential Bayesian method to guarantee consistency between independent and cumulative yields along with the physical constraints on the independent yields. This work was motivated to improve the performance of the ENDF/B-VII.1 library in the case of stable and long-lived cumulative yields due to the inconsistency of ENDF/B-VII.1 fission p;roduct yield and decay data sub-libraries. The revised fission product yields and the new covariance data are proposed as a revision to the fission yield data currently in ENDF/B-VII.1.

  10. MHD turbulence, reconnection, and test-particle acceleration

    NASA Technical Reports Server (NTRS)

    Gray, Perry C.; Matthaeus, William H.

    1992-01-01

    We examine homogeneous MHD turbulence and turbulent magnetic reconnection as possible mechanisms for accelerating cosmic ray particles. Test particle calculations are performed using fields from MHD simulations, and initially Maxwellian particle distributions are shown to evolve into power-law distributions. Simple estimates for both the maximum energy attainable and the mean energies of the accelerated particles are fairly successful and are consistent with timescales for flares and cosmic rays.

  11. Evaluation of the ECAS open cycle MHD power plant design

    NASA Technical Reports Server (NTRS)

    Seikel, G. R.; Staiger, P. J.; Pian, C. C. P.

    1978-01-01

    The Energy Conversion Alternatives Study (ECAS) MHD/steam power plant is described. The NASA critical evaluation of the design is summarized. Performance of the MHD plant is compared to that of the other type ECAS plant designs on the basis of efficiency and the 30-year levelized cost of electricity. Techniques to improve the plant design and the potential performance of lower technology plants requiring shorter development time and lower development cost are then discussed.

  12. Altered lumbar spine structure, biochemistry and biomechanical properties in a canine model of mucopolysaccharidosis type VII

    PubMed Central

    Smith, Lachlan J; Martin, John T; Szczesny, Spencer E; Ponder, Katherine P; Haskins, Mark E; Elliott, Dawn M

    2010-01-01

    Mucopolysaccharidosis VII (MPS VII) is a lysosomal storage disorder characterized by a deficiency in β-glucuronidase activity, leading to systemic accumulation of poorly degraded glycosaminoglycans (GAG). Along with other morbidities, MPS VII is associated with paediatric spinal deformity. The objective of this study was to examine potential associations between abnormal lumbar spine matrix structure and composition in MPS VII, and spine segment and tissue-level mechanical properties, using a naturally occurring canine model with a similar clinical phenotype to the human form of the disorder. Segments from juvenile MPS VII and unaffected dogs were allocated to: radiography, gross morphology, histology, biochemistry, and mechanical testing. MPS VII spines had radiolucent lesions in the vertebral body epiphyses. Histologically, this corresponded to a GAG-rich cartilaginous region in place of bone, and elevated GAG staining was seen in the annulus fibrosus. Biochemically, MPS VII samples had elevated GAG in the outer annulus fibrosus and epiphyses, low calcium in the epiphyses, and high water content in all regions except the nucleus pulposus. MPS VII spine segments had higher range of motion and lower stiffness than controls. Endplate indentation stiffness and failure loads were significantly lower in MPS VII samples, while annulus fibrosus tensile mechanical properties were normal. Vertebral body lesions in MPS VII spines suggest a failure to convert cartilage to bone during development. Low stiffness in these regions likely contributes to mechanical weakness in motion segments and is a potential factor in the progression of spinal deformity. PMID:19918911

  13. Hall-MHD and PIC Modeling of the Conduction-to-Opening Transition in a Plasma Opening Switch

    NASA Astrophysics Data System (ADS)

    Schumer, J. W.; SwanekampDdagger, S. B.; Ottinger, P. F.; Commisso, R. J.; Weber, B. V.

    1998-11-01

    Utilizing the fast opening characteristics of a plasma opening switch (POS), inductive energy storage devices can generate short-duration high-power pulses (<0.1 μ s, >1 TW) with current rise-times on the order of 10 ns. Plasma redistribution and thinning during the POS conduction phase can be modeled adequately with MHD methods. By including the Hall term in Ohm's Law, MHD methods can simulate plasmas with density gradient scale lengths between c/ω_pe < Ln < c/ω_pi. However, the neglect of electron inertia (c/ω_pe) and space-charge separation (λ_De) by single-fluid theory eventually becomes invalid in small gap regions that form during POS opening. PIC methods are well-suited for low-density plasmas, but are numerically taxed by high-density POS regions. An interface converts MHD (Mach2) output into PIC (Magic) input suitable for validating various transition criteria through comparison of current and density distributions from both methods. We will discuss recent progress in interfacing Hall-MHD and PIC simulations. Work supported by Defense Special Weapons Agency. ^ NRL-NRC Research Associate. hspace0.25in ^ JAYCOR, Vienna, VA 22102.

  14. Kinetic-MHD hybrid equilibrium model using a Monte-Carlo calculation of runaway electron distribution function

    NASA Astrophysics Data System (ADS)

    Matsuyama, Akinobu; Aiba, Nobuyuki; Yagi, Masatoshi

    2015-11-01

    An axisymmetric MHD equilibrium model is studied to allow the inclusion of both beam inertia and energy spectrum for runaway electron beam. Following kinetic-MHD hybrid approach, we evaluate the RE beam current from the integrals of the RE distribution function. The distribution function is here evaluated by a relativistic guiding-center trace code ETC-Rel, where we have implemented the effects of collisions, radiations, and exponential growth into the code. Because to directly treat the Dreicer mechanism in particle simulations is time consuming, the primary RE source is modeled by a Monte-Carlo weighing scheme taking into account the instantaneous generation rate. This paper applies ETC-Rel to the parametric study of the MHD equilibrium with different RE beam parameters. Kinetic effects on the MHD equilibrium appears, e.g., as enhanced Shafranov shifts due to the inertia of highly relativistic electrons. A kinetic modification to the equilibrium becomes significant if the contribution of the beam inertia - being increased with the total electron mass of multi-MeV RE populations - becomes large enough to affect the radial force balance. This work was supported in part by MEXT KAKENHI Grant No. 23561009 and 26820404.

  15. Parametric study of potential early commercial MHD power plants

    NASA Technical Reports Server (NTRS)

    Hals, F. A.

    1979-01-01

    Three different reference power plant configurations were considered with parametric variations of the various design parameters for each plant. Two of the reference plant designs were based on the use of high temperature regenerative air preheaters separately fired by a low Btu gas produced from a coal gasifier which was integrated with the power plant. The third reference plant design was based on the use of oxygen enriched combustion air preheated to a more moderate temperature in a tubular type metallic recuperative heat exchanger which is part of the bottoming plant heat recovery system. Comparative information was developed on plant performance and economics. The highest net plant efficiency of about 45 percent was attained by the reference plant design with the use of a high temperature air preheater separately fired with the advanced entrained bed gasifier. The use of oxygen enrichment of the combustion air yielded the lowest cost of generating electricity at a slightly lower plant efficiency. Both of these two reference plant designs are identified as potentially attractive for early MHD power plant applications.

  16. A high current density DC magnetohydrodynamic (MHD) micropump.

    PubMed

    Homsy, Alexandra; Koster, Sander; Eijkel, Jan C T; van den Berg, Albert; Lucklum, F; Verpoorte, E; de Rooij, Nico F

    2005-04-01

    This paper describes the working principle of a DC magnetohydrodynamic (MHD) micropump that can be operated at high DC current densities (J) in 75-microm-deep microfluidic channels without introducing gas bubbles into the pumping channel. The main design feature for current generation is a micromachined frit-like structure that connects the pumping channel to side reservoirs, where platinum electrodes are located. Current densities up to 4000 A m(-2) could be obtained without noticeable Joule heating in the system. The pump performance was studied as a function of current density and magnetic field intensity, as well as buffer ionic strength and pH. Bead velocities of up to 1 mm s(-1) (0.5 microL min(-1)) were observed in buffered solutions using a 0.4 T NdFeB permanent magnet, at an applied current density of 4000 A m(-2). This pump is intended for transport of electrolyte solutions having a relatively high ionic strength (0.5-1 M) in a DC magnetic field environment. The application of this pump for the study of biological samples in a miniaturized total analysis system (microTAS) with integrated NMR detection is foreseen. In the 7 T NMR environment, a minimum 16-fold increase in volumetric flow rate for a given applied current density is expected.

  17. Numerical simulation of propagation of the MHD waves in sunspots

    NASA Astrophysics Data System (ADS)

    Parchevsky, K.; Kosovichev, A.; Khomenko, E.; Olshevsky, V.; Collados, M.

    2010-11-01

    We present results of numerical 3D simulation of propagation of MHD waves in sunspots. We used two self consistent magnetohydrostatic background models of sunspots. There are two main differences between these models: (i) the topology of the magnetic field and (ii) dependence of the horizontal profile of the sound speed on depth. The model with convex shape of the magnetic field lines near the photosphere has non-zero horizorntal perturbations of the sound speed up to the depth of 7.5 Mm (deep model). In the model with concave shape of the magnetic field lines near the photosphere Δ c/c is close to zero everywhere below 2 Mm (shallow model). Strong Alfven wave is generated at the wave source location in the deep model. This wave is almost unnoticeable in the shallow model. Using filtering technique we separated magnetoacoustic and magnetogravity waves. It is shown, that inside the sunspot magnetoacoustic and magnetogravity waves are not spatially separated unlike the case of the horizontally uniform background model. The sunspot causes anisotropy of the amplitude distribution along the wavefront and changes the shape of the wavefront. The amplitude of the waves is reduced inside the sunspot. This effect is stronger for the magnetogravity waves than for magnetoacoustic waves. The shape of the wavefront of the magnetogravity waves is distorted stronger as well. The deep model causes bigger anisotropy for both mgnetoacoustic and magneto gravity waves than the shallow model.

  18. MHD coal combustor technology. Final report, phase II

    SciTech Connect

    Not Available

    1980-09-01

    The design, performance, and testing of a 20-MW coal combustor for scaleup to 50 MW for use in an MHD generator are described. The design incorporates the following key features: (1) a two-stage combustor with an intermediate slag separator to remove slag at a low temperture, thus minimizing enthalpy losses required for heating and vaporizing the slag; (2) a first-stage pentad (four air streams impinging on one coal stream) injector design with demonstrated efficient mixing, promoting high carbon burnout; (3) a two-section first-stage combustion chamber; the first stage using a thin slag-protected refractory layer and the second section using a thick refractory layer, both to minimize heat losses; (4) a refractory lining in the slag separator to minimize heat losses; (5) a second-stage combustor, which provided both de-swirl of the combustion products exiting from the slag separator and simple mixing of the vitiated secondary air and seed; (6) a dense-phase coal feed system to minimize cold carrier gas entering the first-stage combustors; (7) a dry seed injection system using pulverized K/sub 2/CO/sub 3/ with a 1% amorphous, fumed silicon dioxide additive to enhance flowability, resulting in rapid vaporization and ionization and ensuring maximum performance; and (8) a performance evaluation module (PEM) of rugged design based on an existing, successfully-fired unit. (WHK)

  19. Broken Ergodicity in MHD Turbulence in a Spherical Domain

    NASA Technical Reports Server (NTRS)

    Shebalin, John V.; wang, Yifan

    2011-01-01

    Broken ergodicity (BE) occurs in Fourier method numerical simulations of ideal, homogeneous, incompressible magnetohydrodynamic (MHD) turbulence. Although naive statistical theory predicts that Fourier coefficients of fluid velocity and magnetic field are zero-mean random variables, numerical simulations clearly show that low-wave-number coefficients have non-zero mean values that can be very large compared to the associated standard deviation. In other words, large-scale coherent structure (i.e., broken ergodicity) in homogeneous MHD turbulence can spontaneously grow out of random initial conditions. Eigenanalysis of the modal covariance matrices in the probability density functions of ideal statistical theory leads to a theoretical explanation of observed BE in homogeneous MHD turbulence. Since dissipation is minimal at the largest scales, BE is also relevant for resistive magnetofluids, as evidenced in numerical simulations. Here, we move beyond model magnetofluids confined by periodic boxes to examine BE in rotating magnetofluids in spherical domains using spherical harmonic expansions along with suitable boundary conditions. We present theoretical results for 3-D and 2-D spherical models and also present computational results from dynamical simulations of 2-D MHD turbulence on a rotating spherical surface. MHD turbulence on a 2-D sphere is affected by Coriolus forces, while MHD turbulence on a 2-D plane is not, so that 2-D spherical models are a useful (and simpler) intermediate stage on the path to understanding the much more complex 3-D spherical case.

  20. Potassium chloride-bearing ice VII and ice planet dynamics

    NASA Astrophysics Data System (ADS)

    Frank, Mark R.; Scott, Henry P.; Aarestad, Elizabeth; Prakapenka, Vitali B.

    2016-02-01

    Accurate modeling of planetary interiors requires that the pressure-volume-temperature (PVT) properties of phases present within the body be well understood. The high-pressure polymorphs of H2O have been studied extensively due to the abundance of ice phases in icy moons and, likely, vast number of extra-solar planetary bodies, with only select studies evaluating impurity-laden ices. In this study, ice formed from a 1.6 mol percent KCl-bearing aqueous solution was studied up to 32.89 ± 0.19 GPa and 625 K, and the incorporation of K+ and Cl- ionic impurities into the ice VII structure was documented. The compression data at 295 K were fit with a third order Birch-Murnaghan equation of state and yielded a bulk modulus (KT0), its pressure derivative (KT0 ‧), and zero pressure volume (V0) of 24.7 ± 0.9 GPa, 4.44 ± 0.09, and 39.2 ± 0.2 Å3, respectively. The impurity-laden ice was found to be 6-8% denser than ice VII formed from pure H2O. Thermal expansion coefficients were also determined for several isothermal compression curves at elevated temperatures, and a PVT equation of state was obtained. The melting curve of ice VII with incorporated K+ and Cl- was estimated by fitting experimental data up to 10.2 ± 0.4 GPa, where melting occurred at 625 K, to the Simon-Glatzel equation. The melting curve of this impurity-laden ice is systematically depressed relative to that of pure H2O by approximately 45 K and 80 K at 4 and 11 GPa, respectively. A portion of the K+ and Cl- contained within the ice VII structure was observed to exsolve with increasing temperature. This suggests that an internal differentiating process could concentrate a K-rich phase deep within H2O-rich planets, and we speculate that this could supply an additional source of heat through the radioactive decay of 40K. Our data illustrate ice VII can incorporate significant concentrations of K+ and Cl- and increasing the possibility of deep-sourced and solute-rich plumes in moderate to large sized H2O

  1. ENDF/B-VII.1 Neutron Cross Section Data Testing with Critical Assembly Benchmarks and Reactor Experiments

    SciTech Connect

    Kahler, A.; Macfarlane, R E; Mosteller, R D; Kiedrowski, B C; Frankle, S C; Chadwick, M. B.; Mcknight, R D; Lell, R M; Palmiotti, G; Hiruta, h; Herman, Micheal W; Arcilla, r; Mughabghab, S F; Sublet, J C; Trkov, A.; Trumbull, T H; Dunn, Michael E

    2011-01-01

    The ENDF/B-VII.1 library is the latest revision to the United States' Evaluated Nuclear Data File (ENDF). The ENDF library is currently in its seventh generation, with ENDF/B-VII.0 being released in 2006. This revision expands upon that library, including the addition of new evaluated files (was 393 neutron files previously, now 423 including replacement of elemental vanadium and zinc evaluations with isotopic evaluations) and extension or updating of many existing neutron data files. Complete details are provided in the companion paper [1]. This paper focuses on how accurately application libraries may be expected to perform in criticality calculations with these data. Continuous energy cross section libraries, suitable for use with the MCNP Monte Carlo transport code, have been generated and applied to a suite of nearly one thousand critical benchmark assemblies defined in the International Criticality Safety Benchmark Evaluation Project's International Handbook of Evaluated Criticality Safety Benchmark Experiments. This suite covers uranium and plutonium fuel systems in a variety of forms such as metallic, oxide or solution, and under a variety of spectral conditions, including unmoderated (i.e., bare), metal reflected and water or other light element reflected. Assembly eigenvalues that were accurately predicted with ENDF/B-VII.0 cross sections such as unrnoderated and uranium reflected (235)U and (239)Pu assemblies, HEU solution systems and LEU oxide lattice systems that mimic commercial PWR configurations continue to be accurately calculated with ENDF/B-VII.1 cross sections, and deficiencies in predicted eigenvalues for assemblies containing selected materials, including titanium, manganese, cadmium and tungsten are greatly reduced. Improvements are also confirmed for selected actinide reaction rates such as (236)U; (238,242)Pu and (241,243)Am capture in fast systems. Other deficiencies, such as the overprediction of Pu solution system critical eigenvalues

  2. The Mark III VLBI System

    NASA Technical Reports Server (NTRS)

    Rogers, A. E. E.; Whitney, A. R.; Levine, J. I.; Nesman, E. F.; Webber, J. C.; Hinteregger, H. F.

    1988-01-01

    Geodetic measurements have errors in centimeter range. Collection of three reports describes both equipment and results of some measurements taken with Mark III very-long-baseline interferometry (VLBI) system. Has demonstrated high accuracy over short baselines, where phase-delay measurements used. Advanced hardware, called Mark III A, developed to improve system performance and efficiency. Original Mark III hardware and III A subsystem upgrades developed as part of NASA Crustal Dynamics Project at Haystack Observatory.

  3. UH-FLUX: Compact, Energy Efficient Superconducting Asymmetric Energy Recovery LINAC for Ultra-high Fluxes of X-ray and THz Radiation

    SciTech Connect

    Konoplev, Ivan; Ainsworth, Robert; Burt, Graeme; Seryi, Andrei

    2016-06-01

    The conventional ERLs have limited peak beam current because increasing the beam charge and repetition rate leads to appearance of the beam break-up instabilities. At this stage the highest current, from the SRF ERL, is around 300 mA. A single-turn (the beam will be transported through the accelerating section, interaction point and deceleration section of the AERL only once) Asymmetric Energy Recovery LINAC (AERL) is proposed. The RF cells in different sections of the cavity are tuned in such a way that only operating mode is uniform inside all of the cells. The AERL will drive the electron beams with typical energies of 10 - 30 MeV and peak currents above 1 A, enabling the generation of high flux UV/X-rays and high power coherent THz radiation. We aim to build a copper prototype of the RF cavity for a compact AERL to study its EM properties. The final goal is to build AERL based on the superconducting RF cavity. Preliminary design for AERL's cavity has been developed and will be presented. The results of numerical and analytical models and the next steps toward the AERL operation will also be discussed.

  4. ENDF/B-VII.1 Nuclear Data for Science and Technology: Cross Sections, Covariances, Fission Product Yields and Decay Data

    SciTech Connect

    Chadwick, M.B.; Herman, M.; Author : Chadwick,M.B.; Herman,M.; Oblozinsky,P.; Dunn,M.E.; Danon,Y.; Kahler,A.C.; Smith,D.L.; Pritychenko,B.; Arbanas,G.; Arcilla,R.; Brewer,R.; Brown,D.A.; Capote,R.; Carlson,A.D.; Cho,Y.S.; Derrien,H.; Guber,K.; Hale,G.M.; Hoblit,S.; Holloway,S.: Johnson,T.D.; Kawano,T.; Kiedrowski,B.C.; Kim,H.; Kunieda,S.; Larson,N.M.; Leal,L.; Lestone,J.P.; Little,R.C.; McCutchan,E.A.; MacFarlane,R.E.; MacInnes,M.; Mattoon,C.M.; McKnight,R.D.; Mughabghab,S.F.; Nobre,G.P.A.; Palmiotti,G.; Palumbo,A.; Pigni,M.T.; Pronyaev,V.G.; Sayer,R.O.; Sonzogni,A.A.; Summers,N.C.; Talou,P.; Thompson,I.J.; Trkov,A.; Vogt,R.L.; van der Marck,S.C.; Wallner,A.; White,M.C.; Wiarda,D.; Young,P.G.

    2011-12-01

    for a wide range of MCNP simulations of criticality benchmarks, with improved performance coming from new structural material evaluations, especially for Ti, Mn, Cr, Zr and W. For Be we see some improvements although the fast assembly data appear to be mutually inconsistent. Actinide cross section updates are also assessed through comparisons of fission and capture reaction rate measurements in critical assemblies and fast reactors, and improvements are evident. Maxwellian-averaged capture cross sections at 30 keV are also provided for astrophysics applications. We describe the cross section evaluations that have been updated for ENDF/B-VII.1 and the measured data and calculations that motivated the changes, and therefore this paper augments the ENDF/B-VII.0 publication 'ENDF/B-VII.0: Next Generation Evaluated Nuclear Data Library for Nuclear Science and Technology,' Nuclear Data Sheets 107, 2931 (2006).

  5. ENDF/B-VII.1 Nuclear Data for Science and Technology: Cross Sections, Covariances, Fission Product Yields and Decay Data

    NASA Astrophysics Data System (ADS)

    Chadwick, M. B.; Herman, M.; Obložinský, P.; Dunn, M. E.; Danon, Y.; Kahler, A. C.; Smith, D. L.; Pritychenko, B.; Arbanas, G.; Arcilla, R.; Brewer, R.; Brown, D. A.; Capote, R.; Carlson, A. D.; Cho, Y. S.; Derrien, H.; Guber, K.; Hale, G. M.; Hoblit, S.; Holloway, S.; Johnson, T. D.; Kawano, T.; Kiedrowski, B. C.; Kim, H.; Kunieda, S.; Larson, N. M.; Leal, L.; Lestone, J. P.; Little, R. C.; McCutchan, E. A.; MacFarlane, R. E.; MacInnes, M.; Mattoon, C. M.; McKnight, R. D.; Mughabghab, S. F.; Nobre, G. P. A.; Palmiotti, G.; Palumbo, A.; Pigni, M. T.; Pronyaev, V. G.; Sayer, R. O.; Sonzogni, A. A.; Summers, N. C.; Talou, P.; Thompson, I. J.; Trkov, A.; Vogt, R. L.; van der Marck, S. C.; Wallner, A.; White, M. C.; Wiarda, D.; Young, P. G.

    2011-12-01

    of MCNP simulations of criticality benchmarks, with improved performance coming from new structural material evaluations, especially for Ti, Mn, Cr, Zr and W. For Be we see some improvements although the fast assembly data appear to be mutually inconsistent. Actinide cross section updates are also assessed through comparisons of fission and capture reaction rate measurements in critical assemblies and fast reactors, and improvements are evident. Maxwellian-averaged capture cross sections at 30 keV are also provided for astrophysics applications. We describe the cross section evaluations that have been updated for ENDF/B-VII.1 and the measured data and calculations that motivated the changes, and therefore this paper augments the ENDF/B-VII.0 publication [M. B. Chadwick, P. Obložinský, M. Herman, N. M. Greene, R. D. McKnight, D. L. Smith, P. G. Young, R. E. MacFarlane, G. M. Hale, S. C. Frankle, A. C. Kahler, T. Kawano, R. C. Little, D. G. Madland, P. Moller, R. D. Mosteller, P. R. Page, P. Talou, H. Trellue, M. C. White, W. B. Wilson, R. Arcilla, C. L. Dunford, S. F. Mughabghab, B. Pritychenko, D. Rochman, A. A. Sonzogni, C. R. Lubitz, T. H. Trumbull, J. P. Weinman, D. A. Br, D. E. Cullen, D. P. Heinrichs, D. P. McNabb, H. Derrien, M. E. Dunn, N. M. Larson, L. C. Leal, A. D. Carlson, R. C. Block, J. B. Briggs, E. T. Cheng, H. C. Huria, M. L. Zerkle, K. S. Kozier, A. Courcelle, V. Pronyaev, and S. C. van der Marck, "ENDF/B-VII.0: Next Generation Evaluated Nuclear Data Library for Nuclear Science and Technology," Nuclear Data Sheets 107, 2931 (2006)].

  6. An Approach to Mark Arthropods for Mark Capture Type Research

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A series of studies were conducted to validate methods for marking a wide variety of arthropods with inexpensive proteins for mark-capture dispersal research. The markers tested included egg albumin protein in chicken egg whites and casein protein in bovine milk. The first study qualified the effec...

  7. Improving Marking Quality through a Taxonomy of Mark Schemes

    ERIC Educational Resources Information Center

    Ahmed, Ayesha; Pollitt, Alastair

    2011-01-01

    At the heart of most assessments lies a set of questions, and those who write them must achieve "two" things. Not only must they ensure that each question elicits the kind of performance that shows how "good" pupils are at the subject, but they must also ensure that each mark scheme gives more marks to those who are…

  8. EVIDENCE OF ACTIVE MHD INSTABILITY IN EULAG-MHD SIMULATIONS OF SOLAR CONVECTION

    SciTech Connect

    Lawson, Nicolas; Strugarek, Antoine; Charbonneau, Paul E-mail: strugarek@astro.umontreal.ca

    2015-11-10

    We investigate the possible development of magnetohydrodynamical instabilities in the EULAG-MHD “millennium simulation” of Passos and Charbonneau. This simulation sustains a large-scale magnetic cycle characterized by solar-like polarity reversals taking place on a regular multidecadal cadence, and in which zonally oriented bands of strong magnetic fields accumulate below the convective layers, in response to turbulent pumping from above in successive magnetic half-cycles. Key aspects of this simulation include low numerical dissipation and a strongly sub-adiabatic fluid layer underlying the convectively unstable layers corresponding to the modeled solar convection zone. These properties are conducive to the growth and development of two-dimensional instabilities that are otherwise suppressed by stronger dissipation. We find evidence for the action of a non-axisymmetric magnetoshear instability operating in the upper portions of the stably stratified fluid layers. We also investigate the possibility that the Tayler instability may be contributing to the destabilization of the large-scale axisymmetric magnetic component at high latitudes. On the basis of our analyses, we propose a global dynamo scenario whereby the magnetic cycle is driven primarily by turbulent dynamo action in the convecting layers, but MHD instabilities accelerate the dissipation of the magnetic field pumped down into the overshoot and stable layers, thus perhaps significantly influencing the magnetic cycle period. Support for this scenario is found in the distinct global dynamo behaviors observed in an otherwise identical EULAG-MHD simulations, using a different degree of sub-adiabaticity in the stable fluid layers underlying the convection zone.

  9. Fitting Flux Ropes to a Global MHD Solution: A Comparison of Techniques. Appendix 1

    NASA Technical Reports Server (NTRS)

    Riley, Pete; Linker, J. A.; Lionello, R.; Mikic, Z.; Odstrcil, D.; Hidalgo, M. A.; Cid, C.; Hu, Q.; Lepping, R. P.; Lynch, B. J.

    2004-01-01

    Flux rope fitting (FRF) techniques are an invaluable tool for extracting information about the properties of a subclass of CMEs in the solar wind. However, it has proven difficult to assess their accuracy since the underlying global structure of the CME cannot be independently determined from the data. In contrast, large-scale MHD simulations of CME evolution can provide both a global view as well as localized time series at specific points in space. In this study we apply 5 different fitting techniques to 2 hypothetical time series derived from MHD simulation results. Independent teams performed the analysis of the events in "blind tests", for which no information, other than the time series, was provided. F rom the results, we infer the following: (1) Accuracy decreases markedly with increasingly glancing encounters; (2) Correct identification of the boundaries of the flux rope can be a significant limiter; and (3) Results from techniques that infer global morphology must be viewed with caution. In spite of these limitations, FRF techniques remain a useful tool for describing in situ observations of flux rope CMEs.

  10. Fitting Flux Ropes to a Global MHD Solution: A Comparison of Techniques

    NASA Technical Reports Server (NTRS)

    Riley, Pete; Linker, J. A.; Lionello, R.; Mikic, Z.; Odstrcil, D.; Hidalgo, M. A.; Cid, C.; Hu, Q.; Lepping, R. P.; Lynch, B. J.; Rees, A.

    2004-01-01

    Flux rope fitting (FRF) techniques are an invaluable tool for extracting information about the properties of a sub-class of coronal mass ejections (CMEs) in the solar wind. However, it has proven difficult to assess their accuracy since the underlying global structure of the CME cannot be independently determined from the data. In contrast, large-scale MHD simulations of CME evolution can provide both a global view as well as localized time series at specific points in space. In this study we apply five different fitting techniques to two hypothetical time series derived from MHD simulation results. Independent teams performed the analysis of the events in "blind tests", for which no information, other than time series, was provided. From the results, we infer the following: 1) Accuracy decreases markedly with increasingly glancing encounters; 2) Correct identification of the boundaries of the flux rope can be a significant limiter; 3) Results from techniques that infer global morphology must be viewed with caution. In spite of these limitations, FRF techniques remain a useful tool for describing in situ observations of flux rope CMEs.

  11. Anticancer Activity of the Antimicrobial Peptide Scolopendrasin VII Derived from the Centipede, Scolopendra subspinipes mutilans.

    PubMed

    Lee, Joon Ha; Kim, In-Woo; Kim, Sang-Hee; Kim, Mi-Ae; Yun, Eun-Young; Nam, Sung-Hee; Ahn, Mi-Young; Kang, Dongchul; Hwang, Jae Sam

    2015-08-01

    Previously, we performed de novo RNA sequencing of Scolopendra subspinipes mutilans using high-throughput sequencing technology and identified several antimicrobial peptide candidates. Among them, a cationic antimicrobial peptide, scolopendrasin VII, was selected based on its physicochemical properties, such as length, charge, and isoelectric point. Here, we assessed the anticancer activities of scolopendrasin VII against U937 and Jurkat leukemia cell lines. The results showed that scolopendrasin VII decreased the viability of the leukemia cells in MTS assays. Furthermore, flow cytometric analysis and acridine orange/ethidium bromide staining revealed that scolopendrasin VII induced necrosis in the leukemia cells. Scolopendrasin VII-induced necrosis was mediated by specific interaction with phosphatidylserine, which is enriched in the membrane of cancer cells. Taken together, these data indicated that scolopendrasin VII induced necrotic cell death in leukemia cells, probably through interaction with phosphatidylserine. The results provide a useful anticancer peptide candidate and an efficient strategy for new anticancer peptide development.

  12. Field-aligned currents and magnetospheric convection - A comparison between MHD simulations and observations

    NASA Technical Reports Server (NTRS)

    Walker, Raymond J.; Ogino, Tatsuki

    1988-01-01

    A time-dependent three-dimensional MHD model was used to investigate the magnetospheric configuration as a function of the interplanetary magnetic field direction when it was in the y-z plane in geocentric solar magnetospheric coordinates. The model results show large global convection cells, tail lobe cells, high-latitude polarcap cells, and low latitude cells. The field-aligned currents generated in the model magnetosphere and the model convection system are compared with observations from low-altitude polar orbiting satellites.

  13. Development of materials for open-cycle MHD. Quarterly report for the period ending March 1983

    SciTech Connect

    Marchant, D.D.; Bates, J.L.

    1983-07-01

    Pacific Northwest Laboratory (PNL) is conducting an ongoing study of channel components for open-cycle, coal-fired magnetohydrodynamic (MHD) generators. Specifically, electrodes and insulators are being developed. The electrical conductivity has been measured on several compositions based on hafnium oxide, rare earth oxides, and indium oxide. Indium oxide at present appears to be the main constituent required for high conductivity. As part of the development, materials are being corrosion tested in both Montana Rosebud coal slag and potassium sulfate (K/sub 2/SO/sub 4/). The results from three coal slag tests and one K/sub 2/SO/sub 4/ test are discussed in this document.

  14. Magnetohydrodynamics (MHD) Engineering Test Facility (ETF) 200 MWe power plant. Conceptual Design Engineering Report (CDER). Volume 4: Supplementary engineering data

    NASA Astrophysics Data System (ADS)

    1981-09-01

    The reference conceptual design of the Magnetohydrodynamic Engineering Test Facility (ETF), a prototype 200 MWe coal-fired electric generating plant designed to demonstrate the commercial feasibility of open cycle MHD is summarized. Main elements of the design are identified and explained, and the rationale behind them is reviewed. Major systems and plant facilities are listed and discussed. Construction cost and schedule estimates, and identification of engineering issues that should be reexamined are also given. The latest (1980-1981) information from the MHD technology program are integrated with the elements of a conventional steam power electric generating plant. Supplementary Engineering Data (Issues, Background, Performance Assurance Plan, Design Details, System Design Descriptions and Related Drawings) is presented.

  15. Magnetohydrodynamics (MHD) Engineering Test Facility (ETF) 200 MWe power plant. Conceptual Design Engineering Report (CDER). Volume 4: Supplementary engineering data

    NASA Technical Reports Server (NTRS)

    1981-01-01

    The reference conceptual design of the Magnetohydrodynamic Engineering Test Facility (ETF), a prototype 200 MWe coal-fired electric generating plant designed to demonstrate the commercial feasibility of open cycle MHD is summarized. Main elements of the design are identified and explained, and the rationale behind them is reviewed. Major systems and plant facilities are listed and discussed. Construction cost and schedule estimates, and identification of engineering issues that should be reexamined are also given. The latest (1980-1981) information from the MHD technology program are integrated with the elements of a conventional steam power electric generating plant. Supplementary Engineering Data (Issues, Background, Performance Assurance Plan, Design Details, System Design Descriptions and Related Drawings) is presented.

  16. 29 CFR 1604.8 - Relationship of title VII to the Equal Pay Act.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 4 2010-07-01 2010-07-01 false Relationship of title VII to the Equal Pay Act. 1604.8... GUIDELINES ON DISCRIMINATION BECAUSE OF SEX § 1604.8 Relationship of title VII to the Equal Pay Act. (a) The... based on the Equal Pay Act may be raised in a proceeding under title VII. (c) Where such a defense...

  17. Alternative splicing isoforms of synaptotagmin VII in the mouse, rat and human.

    PubMed

    Fukuda, Mitsunori; Ogata, Yukie; Saegusa, Chika; Kanno, Eiko; Mikoshiba, Katsuhiko

    2002-07-01

    Synaptotagmin VII (Syt VII) has been proposed to regulate several different types of Ca2+-dependent exocytosis, but its subcellular localization (lysosome or plasma membrane) and the number of alternative splicing isoforms of Syt VII (single or multiple forms) are matters of controversy. In the present study, we show by reverse transcriptase-PCR analysis that mouse Syt VII has one major isoform (Syt VIIalpha), the original Syt VII, and two minor isoforms (Syt VIIbeta and Syt VIIgamma), which contain unique insertions (of 44 and 116 amino acids respectively) in the spacer domain between the transmembrane and C2 domains of Syt VIIalpha. Similar results were obtained with respect to rat and human Syt VII mRNA expression. An antibody against the N-terminal domain of mouse Syt VII [anti-(Syt VII-N)], which specifically recognized recombinant Syt VII but not other Syt isoforms expressed in COS-7 cells, recognized two major, closely co-migrating bands (p58 and p60) and minor bands of approx. 65 kDa in mouse brain. Immunoaffinity purification of proteins that bind the anti-(Syt VII-N) antibody, and peptide sequence analysis revealed that: (i) the major p58 and p60 bands are identified as adenylate cyclase-associated protein 2; (ii) actin-binding protein is localized at the plasma membrane; and (iii) Syt VIIalpha (65 kDa) is the major Syt VII isoform, but with a much lower expression level than previously thought. It was also shown that FLAG-Syt VII-green-fluorescence-protein fusion protein stably expressed in PC12 cells is localized in the perinuclear region (co-localization with TGN38 protein, even after brefeldin A treatment) and in the tips of neurites (co-localization with Syt I), and not in the plasma membrane.

  18. MHD air preheaters: Results of thermomechanical tests

    SciTech Connect

    Valente, T. )

    1994-12-01

    The thermomechanical tests conducted on four different high-purity periclase magnesia-fired brick were used to select suitable refractory material for the design of a regenerative heat exchanger (Cowper type) for an open-cycle indirect preheating, MHD pilot plant. Tests were conducted under the most severe temperature condition allowable in standard test equipment. The choice among the refractories were made supposing that the ranking established with these tests does not change for higher temperatures (up to 1,900 C). Refractory material M1 exhibited the best behavior. The reported values can be used for the preliminary design of the heat exchanger, using the appropriate safety coefficient. The effective behavior of the materials can be completely understood only with experimental data obtained by the effective operation condition, because size and shape of the material strongly affect the service behavior. The best test is a pilot plant, using scaled-down criteria. This will overcome the difficulty of the standard test at 1,900 C, caused by test equipment limitations.

  19. Flares and MHD Jets in Protostar

    NASA Astrophysics Data System (ADS)

    Hayashi, M.; Shibata, K.; Matsumoto, R.

    We present a magnetic reconnection model for hard X-ray emission and flare-like hard X-ray variabilities associated with protostars detected by ASCA. The energy released by protostellar flares is 102 - 105 times larger than solar flares. Moreover, the spectrum is harder. A new ingredient in protostellar flare is the existence of a protostellar disk which can twist the magnetic fields threading the protostellar disk. We carried out magnetohydrodynamic (MHD) simulations of the disk-star interaction. The closed magnetic loops connecting the central star and the disk are twisted by the rotation of the disk. In the presence of resistivity, magnetic reconnection takes place in the current sheet formed inside the expanding loops. Hot, outgoing plasmoid and post flare loops are formed as a result of the reconnection. Numerical results are consistent with the observed plasma temperature (107 - 108K), the length of the flaring loop (1011-1012cm), the total energy of X-ray flares (~1035-36erg). Furthermore, along the opening magnetic loops, hot jet is ejected in bipolar directions with speed 200-400 km/s. The speed and mass flow rate of the jet is consistent with those of optical jets. Our model can explain both the X-ray flare-like variability and mass outflow in star forming region.

  20. Activation of MHD reconnection on ideal timescales

    NASA Astrophysics Data System (ADS)

    Landi, S.; Papini, E.; Del Zanna, L.; Tenerani, A.; Pucci, F.

    2017-01-01

    Magnetic reconnection in laboratory, space and astrophysical plasmas is often invoked to explain explosive energy release and particle acceleration. However, the timescales involved in classical models within the macroscopic MHD regime are far too slow to match the observations. Here we revisit the tearing instability by performing visco-resistive two-dimensional numerical simulations of the evolution of thin current sheets, for a variety of initial configurations and of values of the Lunquist number S, up to 107. Results confirm that when the critical aspect ratio of S 1/3 is reached in the reconnecting current sheets, the instability proceeds on ideal (Alfvénic) macroscopic timescales, as required to explain observations. Moreover, the same scaling is seen to apply also to the local, secondary reconnection events triggered during the nonlinear phase of the tearing instability, thus accelerating the cascading process to increasingly smaller spatial and temporal scales. The process appears to be robust, as the predicted scaling is measured both in inviscid simulations and when using a Prandtl number P  =  1 in the viscous regime.