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Sample records for string-guided fast transport

  1. A model for fast axonal transport.

    PubMed

    Blum, J J; Reed, M C

    1985-01-01

    A model for fast axonal transport is developed in which the essential features are that organelles may interact with mechanochemical cross-bridges that in turn interact with microtubules, forming an organelle-engine-microtubule complex which is transported along the microtubules. Computer analysis of the equations derived to describe such a system show that most of the experimental observations on fast axonal transport can be simulated by the model, indicating that the model is useful for the interpretation and design of experiments aimed at clarifying the mechanism of fast axonal transport. PMID:2416456

  2. Fast atomic transport without vibrational heating

    SciTech Connect

    Torrontegui, E.; Ibanez, S.; Chen Xi; Ruschhaupt, A.; Guery-Odelin, D.; Muga, J. G.

    2011-01-15

    We use the dynamical invariants associated with the Hamiltonian of an atom in a one dimensional moving trap to inverse engineer the trap motion and perform fast atomic transport without final vibrational heating. The atom is driven nonadiabatically through a shortcut to the result of adiabatic, slow trap motion. For harmonic potentials this only requires designing appropriate trap trajectories, whereas perfect transport in anharmonic traps may be achieved by applying an extra field to compensate the forces in the rest frame of the trap. The results can be extended to atom stopping or launching. The limitations due to geometrical constraints, energies, and accelerations involved are analyzed along with the relation to previous approaches based on classical trajectories or ''fast-forward'' and ''bang-bang'' methods, which can be integrated in the invariant-based framework.

  3. Measurements of classical transport of fast ions

    SciTech Connect

    Zhao, L.; Heidbrink, W.W.; Boehmer, H.; McWilliams, R.; Leneman, D.; Vincena, S.

    2005-05-15

    To study the fast-ion transport in a well controlled background plasma, a 3-cm diameter rf ion gun launches a pulsed, {approx}300 eV ribbon shaped argon ion beam parallel to or at 15 deg. to the magnetic field in the Large Plasma Device (LAPD) [W. Gekelman, H. Pfister, Z. Lucky, J. Bamber, D. Leneman, and J. Maggs, Rev. Sci. Instrum. 62, 2875 (1991)] at UCLA. The parallel energy of the beam is measured by a two-grid energy analyzer at two axial locations (z=0.32 m and z=6.4 m) from the ion gun in LAPD. The calculated ion beam slowing-down time is consistent to within 10% with the prediction of classical Coulomb collision theory using the LAPD plasma parameters measured by a Langmuir probe. To measure cross-field transport, the beam is launched at 15 deg. to the magnetic field. The beam then is focused periodically by the magnetic field to avoid geometrical spreading. The radial beam profile measurements are performed at different axial locations where the ion beam is periodically focused. The measured cross-field transport is in agreement to within 15% with the analytical classical collision theory and the solution to the Fokker-Planck kinetic equation. Collisions with neutrals have a negligible effect on the beam transport measurement but do attenuate the beam current.

  4. Turbulent transport of fast ions in the Large Plasma Device

    SciTech Connect

    Zhou Shu; Heidbrink, W. W.; Boehmer, H.; McWilliams, R.; Carter, T.; Vincena, S.; Tripathi, S. K. P.; Popovich, P.; Friedman, B.; Jenko, F.

    2010-09-15

    Strong drift wave turbulence is observed in the Large Plasma Device [H. Gekelman et al., Rev. Sci. Instrum. 62, 2875 (1991)] on density gradients produced by a plate limiter. Energetic lithium ions orbit through the turbulent region. Scans with a collimated ion analyzer and with Langmuir probes give detailed profiles of the fast ion spatial distribution and the fluctuating fields. The fast ion transport decreases rapidly with increasing fast ion gyroradius. Unlike the diffusive transport caused by Coulomb collisions, in this case the turbulent transport is nondiffusive. Analysis and simulation suggest that such nondiffusive transport is due to the interaction of the fast ions with stationary two-dimensional electrostatic turbulence.

  5. Evidence for fast-ion transport by microturbulence.

    PubMed

    Heidbrink, W W; Park, J M; Murakami, M; Petty, C C; Holcomb, C; Van Zeeland, M A

    2009-10-23

    Cross-field diffusion of energetic ions by microturbulence is measured during neutral-beam injection into the DIII-D tokamak. Fast-ion D(alpha), neutron, and motional Stark effect measurements diagnose the fast-ion distribution function. As expected for transport by plasma turbulence, anomalies relative to the classical prediction are greatest in high temperature plasmas, at low fast-ion energy, and at larger minor radius. Theoretical estimates of fast-ion diffusion are comparable to experimental levels.

  6. Evidence for Fast-Ion Transport by Microturbulence

    SciTech Connect

    Heidbrink, W. W.; Park, Jin Myung; Murakami, Masanori; Petty, C C.; Holcomb, C T; Van Zeeland, Michael

    2009-01-01

    Cross-field diffusion of energetic ions by microturbulence is measured during neutral-beam injection into the DIII-D tokamak. Fast-ion D-alpha, neutron, and motional Stark effect measurements diagnose the fastion distribution function. As expected for transport by plasma turbulence, anomalies relative to the classical prediction are greatest in high temperature plasmas, at low fast-ion energy, and at larger minor radius. Theoretical estimates of fast-ion diffusion are comparable to experimental levels.

  7. Evidence for Fast-Ion Transport by Microturbulence

    SciTech Connect

    Heidbrink, W. W.; Park, J. M.; Murakami, M.; Petty, C. C.; Van Zeeland, M. A.; Holcomb, C.

    2009-10-23

    Cross-field diffusion of energetic ions by microturbulence is measured during neutral-beam injection into the DIII-D tokamak. Fast-ion D{sub {alpha}}, neutron, and motional Stark effect measurements diagnose the fast-ion distribution function. As expected for transport by plasma turbulence, anomalies relative to the classical prediction are greatest in high temperature plasmas, at low fast-ion energy, and at larger minor radius. Theoretical estimates of fast-ion diffusion are comparable to experimental levels.

  8. Automated measurement of fast mitochondrial transport in neurons

    PubMed Central

    Miller, Kyle E.; Liu, Xin-An; Puthanveettil, Sathyanarayanan V.

    2015-01-01

    There is growing recognition that fast mitochondrial transport in neurons is disrupted in multiple neurological diseases and psychiatric disorders. However, a major constraint in identifying novel therapeutics based on mitochondrial transport is that the large-scale analysis of fast transport is time consuming. Here we describe methodologies for the automated analysis of fast mitochondrial transport from data acquired using a robotic microscope. We focused on addressing questions of measurement precision, speed, reliably, workflow ease, statistical processing, and presentation. We used optical flow and particle tracking algorithms, implemented in ImageJ, to measure mitochondrial movement in primary cultured cortical and hippocampal neurons. With it, we are able to generate complete descriptions of movement profiles in an automated fashion of hundreds of thousands of mitochondria with a processing time of approximately one hour. We describe the calibration of the parameters of the tracking algorithms and demonstrate that they are capable of measuring the fast transport of a single mitochondrion. We then show that the methods are capable of reliably measuring the inhibition of fast mitochondria transport induced by the disruption of microtubules with the drug nocodazole in both hippocampal and cortical neurons. This work lays the foundation for future large-scale screens designed to identify compounds that modulate mitochondrial motility. PMID:26578890

  9. Fast Ignition Transport Simulations for NIF

    SciTech Connect

    Strozzi, D J; Grote, D P; Tabak, M; Cohen, B I; Town, R P; Kemp, A J

    2009-10-05

    This paper shows work at Lawrence Livermore National Lab (LLNL) devoted to modeling the propagation of, and heating by, a relativistic electron beam in a idealized dense fuel assembly for fast ignition. The implicit particle-in-cell (PIC) code LSP is used. Experiments planned on the National Ignition Facility (NIF) in the next few years using the Advanced Radiography Capability (ARC) short-pulse laser motivate this work. We demonstrate significant improvement in the heating of dense fuel due to magnetic forces, increased beam collimation, and insertion of a finite-radius carbon region between the beam excitation and fuel regions.

  10. Fast electron generation and transport in a turbulent, magnetized plasma

    SciTech Connect

    Stoneking, W.R.

    1994-05-01

    The nature of fast electron generation and transport in the Madison Symmetric Torus (MST) reversed field pinch (RFP) is investigated using two electron energy analyzer (EEA) probes and a thermocouple calorimeter. The parallel velocity distribution of the fast electron population is well fit by a drifted Maxwellian distribution with temperature of about 100 eV and drift velocity of about 2 {times} 10{sup 6} m/s. Cross-calibration of the EEA with the calorimeter provides a measurement of the fast electron perpendicular temperature of 30 eV, much lower than the parallel temperature, and is evidence that the kinetic dynamo mechanism (KDT) is not operative in MST. The fast electron current is found to match to the parallel current at the edge, and the fast electron density is about 4 {times} 10{sup 11} cm{sup {minus}3} independent of the ratio of the applied toroidal electric field to the critical electric field for runaways. First time measurements of magnetic fluctuation induced particle transport are reported. By correlating electron current fluctuations with radial magnetic fluctuations the transported flux of electrons is found to be negligible outside r/a{approximately}0.9, but rises the level of the expected total particle losses inside r/a{approximately}0.85. A comparison of the measured diffusion coefficient is made with the ausilinear stochastic diffusion coefficient. Evidence exists that the reduction of the transport is due to the presence of a radial ambipolar electric field of magnitude 500 V/m, that acts to equilibrate the ion and electron transport rates. The convective energy transport associated with the measured particle transport is large enough to account for the observed magnetic fluctuation induced energy transport in MST.

  11. Experiment to measure fast ion transport by magnetic fluctuations

    NASA Astrophysics Data System (ADS)

    Preiwisch, Adam; Heidbrink, William; Boehmer, Heinz; McWilliams, Roger; Carter, Troy; Gekelman, Walter; Tripathi, Shreekrishna; van Compernolle, Bart; Vincena, Steve

    2013-10-01

    Fast ion transport in a linear magnetic field is studied at the upgraded Large Plasma Device. Recent developments allow for the generation of turbulent magnetic flux ropes, produced by a hot LaB6 cathode situated in the main chamber.1 A large-gyroradius, energetic lithium ion beam (300 <= Efast /Ti <= 1000) is passed through the turbulent region and collected by a collimated analyzer downstream, yielding a detailed plane profile of the fast ion distribution.2 Magnetic fluctuations, density, and temperature profiles are also obtained via probes. Enhanced fast-ion transport is clearly observed in the form of beam broadening. Early analysis shows broadband ion saturation current and magnetic fluctuations attributed to the flux ropes. A follow up experiment is currently under way to address whether the increased transport is primarily attributed to magnetic fields, associated electric fields, or increased Coulomb scattering.

  12. Fast Ion Transport by Magnetic Flux Ropes

    NASA Astrophysics Data System (ADS)

    Preiwisch, Adam; Heidbrink, William; Boehmer, Heinrich; McWilliams, Roger; Carter, Troy; Gekelman, Walter; Tripathi, Shreekrishna; Compernolle, Bart; Vincena, Steven

    2014-10-01

    Energetic Lithium test ions (500 <= Efast/Ti <= 1000) are launched in a Helium plasma in the presence of current-produced magnetic flux ropes at the upgraded Large Plasma Device (LAPD) at UCLA. Perturbing flux ropes are introduced via a hot, biased LaB6 cathode in the main chamber. Ion beam broadening up to fifty percent above background levels is observed in the radial direction after passing through the flux rope region (Te,max = 7 eV, Bperp = 7G, ΔV = 160 V). Density, temperature, and magnetic fluctuation profiles are also obtained. A noise model has been developed to assess the quality of ion signals during the flux rope discharge period. The enhancement to transport may be a result of increased Coulomb scattering, magnetic fluctuations, or electric fields. Further analysis to determine the primary mechanism is ongoing.

  13. Transport Simulations for Fast Ignition on NIF

    SciTech Connect

    Strozzi, D J; Tabak, M; Grote, D P; Cohen, B I; Shay, H D; Town, R J; Kemp, A J; Key, M

    2009-10-26

    We are designing a full hydro-scale cone-guided, indirect-drive FI coupling experiment, for NIF, with the ARC-FIDO short-pulse laser. Current rad-hydro designs with limited fuel jetting into cone tip are not yet adequate for ignition. Designs are improving. Electron beam transport simulations (implicit-PIC LSP) show: (1) Magnetic fields and smaller angular spreads increase coupling to ignition-relevant 'hot spot' (20 um radius); (2) Plastic CD (for a warm target) produces somewhat better coupling than pure D (cryogenic target) due to enhanced resistive B fields; and (3) The optimal T{sub hot} for this target is {approx} 1 MeV; coupling falls by 3x as T{sub hot} rises to 4 MeV.

  14. Fast algorithms for transport models. Final report

    SciTech Connect

    Manteuffel, T.A.

    1994-10-01

    This project has developed a multigrid in space algorithm for the solution of the S{sub N} equations with isotropic scattering in slab geometry. The algorithm was developed for the Modified Linear Discontinuous (MLD) discretization in space which is accurate in the thick diffusion limit. It uses a red/black two-cell {mu}-line relaxation. This relaxation solves for all angles on two adjacent spatial cells simultaneously. It takes advantage of the rank-one property of the coupling between angles and can perform this inversion in O(N) operations. A version of the multigrid in space algorithm was programmed on the Thinking Machines Inc. CM-200 located at LANL. It was discovered that on the CM-200 a block Jacobi type iteration was more efficient than the block red/black iteration. Given sufficient processors all two-cell block inversions can be carried out simultaneously with a small number of parallel steps. The bottleneck is the need for sums of N values, where N is the number of discrete angles, each from a different processor. These are carried out by machine intrinsic functions and are well optimized. The overall algorithm has computational complexity O(log(M)), where M is the number of spatial cells. The algorithm is very efficient and represents the state-of-the-art for isotropic problems in slab geometry. For anisotropic scattering in slab geometry, a multilevel in angle algorithm was developed. A parallel version of the multilevel in angle algorithm has also been developed. Upon first glance, the shifted transport sweep has limited parallelism. Once the right-hand-side has been computed, the sweep is completely parallel in angle, becoming N uncoupled initial value ODE`s. The author has developed a cyclic reduction algorithm that renders it parallel with complexity O(log(M)). The multilevel in angle algorithm visits log(N) levels, where shifted transport sweeps are performed. The overall complexity is O(log(N)log(M)).

  15. Fast Optimal Transport Averaging of Neuroimaging Data.

    PubMed

    Gramfort, A; Peyré, G; Cuturi, M

    2015-01-01

    Knowing how the Human brain is anatomically and functionally organized at the level of a group of healthy individuals or patients is the primary goal of neuroimaging research. Yet computing an average of brain imaging data defined over a voxel grid or a triangulation remains a challenge. Data are large, the geometry of the brain is complex and the between subjects variability leads to spatially or temporally non-overlapping effects of interest. To address the problem of variability, data are commonly smoothed before performing a linear group averaging. In this work we build on ideas originally introduced by Kantorovich to propose a new algorithm that can average efficiently non-normalized data defined over arbitrary discrete domains using transportation metrics. We show how Kantorovich means can be linked to Wasserstein barycenters in order to take advantage of the entropic smoothing approach used by. It leads to a smooth convex optimization problem and an algorithm with strong convergence guarantees. We illustrate the versatility of this tool and its empirical behavior on functional neuroimaging data, functional MRI and magnetoencephalography (MEG) source estimates, defined on voxel grids and triangulations of the folded cortical surface. PMID:26221679

  16. Reduced Fast Ion Transport Model For The Tokamak Transport Code TRANSP

    SciTech Connect

    Podesta,, Mario; Gorelenkova, Marina; White, Roscoe

    2014-02-28

    Fast ion transport models presently implemented in the tokamak transport code TRANSP [R. J. Hawryluk, in Physics of Plasmas Close to Thermonuclear Conditions, CEC Brussels, 1 , 19 (1980)] are not capturing important aspects of the physics associated with resonant transport caused by instabilities such as Toroidal Alfv en Eigenmodes (TAEs). This work describes the implementation of a fast ion transport model consistent with the basic mechanisms of resonant mode-particle interaction. The model is formulated in terms of a probability distribution function for the particle's steps in phase space, which is consistent with the MonteCarlo approach used in TRANSP. The proposed model is based on the analysis of fast ion response to TAE modes through the ORBIT code [R. B. White et al., Phys. Fluids 27 , 2455 (1984)], but it can be generalized to higher frequency modes (e.g. Compressional and Global Alfv en Eigenmodes) and to other numerical codes or theories.

  17. Membranes for nanometer-scale mass fast transport

    DOEpatents

    Bakajin, Olgica; Holt, Jason; Noy, Aleksandr; Park, Hyung Gyu

    2011-10-18

    Nanoporous membranes comprising single walled, double walled, and multiwalled carbon nanotubes embedded in a matrix material were fabricated for fluid mechanics and mass transfer studies on the nanometer scale and commercial applications. Average pore size can be 2 nm to 20 nm, or seven nm or less, or two nanometers or less. The membrane can be free of large voids spanning the membrane such that transport of material such as gas or liquid occurs exclusively through the tubes. Fast fluid, vapor, and liquid transport are observed. Versatile micromachining methods can be used for membrane fabrication. A single chip can comprise multiple membranes. These membranes are a robust platform for the study of confined molecular transport, with applications in liquid and gas separations and chemical sensing including desalination, dialysis, and fabric formation.

  18. Energy transport in ultra-fast eated solid targets

    NASA Astrophysics Data System (ADS)

    Sentoku, Yasuhiko; Johzaki, Tomoyuki; Kemp, Andreas

    2008-11-01

    We discuss hot electron generation in ultra intense laser interaction with initially non-ionized matter. Hot electron energy and the transport inside the target are strongly affected by collisional effects and ionization processes, especially in high-Z material. We have introduced an ionization model into our collisional particle-in-cell code, PICLS, to study hot electron transport in ultra-fast heated matter. Our description of collisional ionization is based on the Thomas-Fermi model, where a local average charge state is calculated from the bulk electron temperature and density. Field ionization is taken into account for ionization of low density plasmas. We have studied laser matter interaction under an irradiation of a laser with 10^20W/cm^2. A strong heat inhibition within a micron distance was observed in a gold target because of the large number of lower energy hot electrons produced at the steepened interface by the laser photon pressure. We will discuss the generation of hot electrons and their transport in ultra-fast heated solid targets of various materials.

  19. Behaviour of fast electron transport in solid targets

    NASA Astrophysics Data System (ADS)

    Koenig, M.; Baton, S. D.; Benuzzi-Mounaix, A.; Fuchs, J.; Loupias, B.; Guillou, P.; Batani, D.; Morace, A.; Piazza, D.; Kodama, R.; Norimatsu, T.; Nakatsutsumi, M.; Aglitskiy, Y.; Rousseaux, C.

    2006-06-01

    One of the main issues of the fast ignitor scheme is the role of fast electron transport in the solid fuel heating. Recent experiments used a new target scheme based on the use of cone to guide the PW laser and enhance the electron production. In this context it is fundamental to understand the physics underlying this new target scheme. We report here recent and preliminary results of ultra-intense laser pulse interaction with three layer targets in presence of the cone or without. Experiments have been performed at LULI with the 100 TW laser facility, at intensities up to 3 1019 W/cm2. Several diagnostics have been implemented (2D Kα imaging, Kα spectroscopy and rear side imaging, protons emission) to quantify the cone effect.

  20. Fast and efficient transport of large ion clouds

    NASA Astrophysics Data System (ADS)

    Kamsap, M. R.; Pedregosa-Gutierrez, J.; Champenois, C.; Guyomarc'h, D.; Houssin, M.; Knoop, M.

    2015-10-01

    The manipulation of trapped charged particles by electric fields is an accurate, robust, and reliable technique for many applications or experiments in high-precision spectroscopy. The transfer of an ion sample between multiple traps allows the use of a tailored environment in quantum information, cold chemistry, or frequency metrology experiments. In this article, we experimentally study the transport of ion clouds of up to 80 000 ions over a distance of 20 mm inside a linear radio-frequency trap. Ion transport is controlled by a transfer function, which is designed taking into account the local electric potentials. We observe that the ion response is very sensitive to the details of the description of the electric potential. Nevertheless, we show that fast transport—with a total duration of 100 μ s —results in transport efficiencies attaining values higher than 90% of the ion number, even with large ion clouds. For clouds smaller than 2000 ions, a 100% transfer efficiency is observed. Transport induced heating, which depends on the transport duration, is also analyzed.

  1. A Novel and Fast Purification Method for Nucleoside Transporters.

    PubMed

    Hao, Zhenyu; Thomsen, Maren; Postis, Vincent L G; Lesiuk, Amelia; Sharples, David; Wang, Yingying; Bartlam, Mark; Goldman, Adrian

    2016-01-01

    Nucleoside transporters (NTs) play critical biological roles in humans, and to understand the molecular mechanism of nucleoside transport requires high-resolution structural information. However, the main bottleneck for structural analysis of NTs is the production of pure, stable, and high quality native protein for crystallization trials. Here we report a novel membrane protein expression and purification strategy, including construction of a high-yield membrane protein expression vector, and a new and fast purification protocol for NTs. The advantages of this strategy are the improved time efficiency, leading to high quality, active, stable membrane proteins, and the efficient use of reagents and consumables. Our strategy might serve as a useful point of reference for investigating NTs and other membrane proteins by clarifying the technical points of vector construction and improvements of membrane protein expression and purification. PMID:27376071

  2. A Novel and Fast Purification Method for Nucleoside Transporters

    PubMed Central

    Hao, Zhenyu; Thomsen, Maren; Postis, Vincent L. G.; Lesiuk, Amelia; Sharples, David; Wang, Yingying; Bartlam, Mark; Goldman, Adrian

    2016-01-01

    Nucleoside transporters (NTs) play critical biological roles in humans, and to understand the molecular mechanism of nucleoside transport requires high-resolution structural information. However, the main bottleneck for structural analysis of NTs is the production of pure, stable, and high quality native protein for crystallization trials. Here we report a novel membrane protein expression and purification strategy, including construction of a high-yield membrane protein expression vector, and a new and fast purification protocol for NTs. The advantages of this strategy are the improved time efficiency, leading to high quality, active, stable membrane proteins, and the efficient use of reagents and consumables. Our strategy might serve as a useful point of reference for investigating NTs and other membrane proteins by clarifying the technical points of vector construction and improvements of membrane protein expression and purification. PMID:27376071

  3. Modeling Fast Ion Transport in TAE Avalanches in NSTX

    SciTech Connect

    Fredrickson, E D; Bell, R E; Darrow, D; Gorelenkov, N N; Kramer, G; Kubota, S; Levinton, F M; Liu, D; Medley, S S; Podesta, M; Tritz, K

    2009-08-17

    Experiments on the National Spherical Torus Experiment [M. Ono, et al., Nucl. Fusion 40 (2000) 557 ] have found strong bursts of Toroidal Alfven Eigenmode (TAE) activity correlated with abrupt drops in the neutron rate. A fairly complete data set offers the opportunity to benchmark the NOVA [C. Z. Cheng, Phys. Reports 211, 1-51 (1992)] and ORBIT [R. B. White and M. S. Chance, Phys. Fluids 27, 2455 (1984)] codes in the low aspect ratio tokamak (ST) geometry. The internal structure of TAE were modeled with NOVA and good agreement is found with measurements made with an array of five fixed-frequency reflectometers. The fast-ion transport resulting from these bursts of multiple TAE were then modeled with the ORBIT code. The simulations are reasonably consistent with the observed drop in neutron rate. While these results represent our best attempts to find agreement, we believe that further refinements in both the simulation of the TAE structure and in the modeling of the fast ion transport are needed. Benchmarking stability codes against present experiments is an important step in developing the predictive capability needed to plan future experiments.

  4. Design of a transportable high efficiency fast neutron spectrometer

    NASA Astrophysics Data System (ADS)

    Roecker, C.; Bernstein, A.; Bowden, N. S.; Cabrera-Palmer, B.; Dazeley, S.; Gerling, M.; Marleau, P.; Sweany, M. D.; Vetter, K.

    2016-08-01

    A transportable fast neutron detection system has been designed and constructed for measuring neutron energy spectra and flux ranging from tens to hundreds of MeV. The transportability of the spectrometer reduces the detector-related systematic bias between different neutron spectra and flux measurements, which allows for the comparison of measurements above or below ground. The spectrometer will measure neutron fluxes that are of prohibitively low intensity compared to the site-specific background rates targeted by other transportable fast neutron detection systems. To measure low intensity high-energy neutron fluxes, a conventional capture-gating technique is used for measuring neutron energies above 20 MeV and a novel multiplicity technique is used for measuring neutron energies above 100 MeV. The spectrometer is composed of two Gd containing plastic scintillator detectors arranged around a lead spallation target. To calibrate and characterize the position dependent response of the spectrometer, a Monte Carlo model was developed and used in conjunction with experimental data from gamma ray sources. Multiplicity event identification algorithms were developed and used with a Cf-252 neutron multiplicity source to validate the Monte Carlo model Gd concentration and secondary neutron capture efficiency. The validated Monte Carlo model was used to predict an effective area for the multiplicity and capture gating analyses. For incident neutron energies between 100 MeV and 1000 MeV with an isotropic angular distribution, the multiplicity analysis predicted an effective area of 500 cm2 rising to 5000 cm2. For neutron energies above 20 MeV, the capture-gating analysis predicted an effective area between 1800 cm2 and 2500 cm2. The multiplicity mode was found to be sensitive to the incident neutron angular distribution.

  5. Visualizing fast electron energy transport into laser-compressed high-density fast-ignition targets

    NASA Astrophysics Data System (ADS)

    Jarrott, L. C.; Wei, M. S.; McGuffey, C.; Solodov, A. A.; Theobald, W.; Qiao, B.; Stoeckl, C.; Betti, R.; Chen, H.; Delettrez, J.; Döppner, T.; Giraldez, E. M.; Glebov, V. Y.; Habara, H.; Iwawaki, T.; Key, M. H.; Luo, R. W.; Marshall, F. J.; McLean, H. S.; Mileham, C.; Patel, P. K.; Santos, J. J.; Sawada, H.; Stephens, R. B.; Yabuuchi, T.; Beg, F. N.

    2016-05-01

    Recent progress in kilojoule-scale high-intensity lasers has opened up new areas of research in radiography, laboratory astrophysics, high-energy-density physics, and fast-ignition (FI) laser fusion. FI requires efficient heating of pre-compressed high-density fuel by an intense relativistic electron beam produced from laser-matter interaction. Understanding the details of electron beam generation and transport is crucial for FI. Here we report on the first visualization of fast electron spatial energy deposition in a laser-compressed cone-in-shell FI target, facilitated by doping the shell with copper and imaging the K-shell radiation. Multi-scale simulations accompanying the experiments clearly show the location of fast electrons and reveal key parameters affecting energy coupling. The approach provides a more direct way to infer energy coupling and guide experimental designs that significantly improve the laser-to-core coupling to 7%. Our findings lay the groundwork for further improving efficiency, with 15% energy coupling predicted in FI experiments using an existing megajoule-scale laser driver.

  6. Fast ion transport induced by saturated infernal mode

    SciTech Connect

    Marchenko, V. S.

    2014-05-15

    Tokamak discharges with extended weak-shear central core are known to suffer from infernal modes when the core safety factor approaches the mode ratio. These modes can cause an outward convection of the well-passing energetic ions deposited in the core by fusion reactions and/or neutral beam injection. Convection mechanism consists in collisional slowing down of energetic ions trapped in the Doppler-precession resonance with a finite-amplitude infernal mode. Convection velocity can reach a few m/s in modern spherical tori. Possible relation of this transport with the enhanced fast ion losses in the presence of “long lived modes” in the MAST tokamak [I. T. Chapman et al., Nucl. Fusion 50, 045007 (2010)] is discussed.

  7. Fast-electron transport in cylindrically laser-compressed matter

    NASA Astrophysics Data System (ADS)

    Perez, F.; Koenig, M.; Batani, D.; Baton, S. D.; Beg, F. N.; Benedetti, C.; Brambrink, E.; Chawla, S.; Dorchies, F.; Fourment, C.; Galimberti, M.; Gizzi, L. A.; Heathcote, R.; Higginson, D. P.; Hulin, S.; Jafer, R.; Koester, P.; Labate, L.; Lancaster, K.; Mac Kinnon, A. J.; McPhee, A. G.; Nazarov, W.; Nicolai, P.; Pasley, J.; Ravasio, A.; Richetta, M.; Santos, J. J.; Sgattoni, A.; Spindloe, C.; Vauzour, B.; Volpe, L.

    2009-12-01

    Experimental and theoretical results of relativistic electron transport in cylindrically compressed matter are presented. This experiment, which is a part of the HiPER roadmap, was achieved on the VULCAN laser facility (UK) using four long pulses beams (~4 × 50 J, 1 ns, at 0.53 µm) to compress a hollow plastic cylinder filled with plastic foam of three different densities (0.1, 0.3 and 1 g cm-3). 2D simulations predict a density of 2-5 g cm-3 and a plasma temperature up to 100 eV at maximum compression. A short pulse (10 ps, 160 J) beam generated fast electrons that propagate through the compressed matter by irradiating a nickel foil at an intensity of 5 × 1018 W cm-2. X-ray spectrometer and imagers were implemented in order to estimate the compressed plasma conditions and to infer the hot electron characteristics. Results are discussed and compared with simulations.

  8. Bifurcation of Velocity Distributions in Cooperative Transport of Filaments by Fast and Slow Motors

    PubMed Central

    Li, Xin; Lipowsky, Reinhard; Kierfeld, Jan

    2013-01-01

    Several intracellular processes are governed by two different species of molecular motors, fast and slow ones, that both move in the same direction along the filaments but with different velocities. The transport of filaments arising from the cooperative action of these motors has been recently studied by three in vitro experiments, in which the filament velocity was measured for varying fraction of the fast motors adsorbed onto substrate surfaces in a gliding assay. As the fast motor fraction was increased, two experiments found a smooth change whereas the third one observed an abrupt increase of the filament velocity. Here, we show that all of these experimental results reflect the competition between fast and slow motors and can be understood in terms of an underlying saddle-node bifurcation. The comparison between theory and experiment leads to predictions for the detachment forces of the two motor species. Our theoretical study shows the existence of three different motility regimes: 1), fast transport with a single velocity; 2), slow transport with a single velocity; and 3), bistable transport, where the filament velocity stochastically switches between fast and slow transport. We determine the parameter regions for these regimes in terms of motility diagrams as a function of the surface fraction of fast motors and microscopic single-motor parameters. An abrupt increase of the filament velocity for an increasing fraction of fast motors is associated with the occurrence of bistable transport. PMID:23442917

  9. Thermal plasma and fast ion transport in electrostatic turbulence in the large plasma device

    SciTech Connect

    Zhou Shu; Heidbrink, W. W.; Boehmer, H.; McWilliams, R.; Carter, T. A.; Vincena, S.; Tripathi, S. K. P.; Van Compernolle, B.

    2012-05-15

    The transport of thermal plasma and fast ions in electrostatic microturbulence is studied. Strong density and potential fluctuations ({delta}n/n{approx}{delta}{phi}/kT{sub e}{approx} 0.5, f {approx} 5-50 kHz) are observed in the large plasma device (LAPD) [W. Gekelman, H. Pfister, Z. Lucky et al., Rev. Sci. Instrum. 62, 2875 (1991)] in density gradient regions produced by obstacles with slab or cylindrical geometry. Wave characteristics and the associated plasma transport are modified by driving sheared E Multiplication-Sign B drift through biasing the obstacle and by modification of the axial magnetic fields (B{sub z}) and the plasma species. Cross-field plasma transport is suppressed with small bias and large B{sub z} and is enhanced with large bias and small B{sub z}. The transition in thermal plasma confinement is well explained by the cross-phase between density and potential fluctuations. Large gyroradius lithium fast ion beam ({rho}{sub fast}/{rho}{sub s} {approx} 10) orbits through the turbulent region. Scans with a collimated analyzer give detailed profiles of the fast ion spatial-temporal distribution. Fast-ion transport decreases rapidly with increasing fast-ion energy and gyroradius. Background waves with different scale lengths also alter the fast ion transport. Experimental results agree well with gyro-averaging theory. When the fast ion interacts with the wave for most of a wave period, a transition from super-diffusive to sub-diffusive transport is observed, as predicted by diffusion theory. Besides turbulent-wave-induced fast-ion transport, the static radial electric field (E{sub r}) from biasing the obstacle leads to drift of the fast-ion beam centroid. The drift and broadening of the beam due to static E{sub r} are evaluated both analytically and numerically. Simulation results indicate that the E{sub r} induced transport is predominately convective.

  10. Fast axonal transport of kinesin in the rat visual system: functionality of kinesin heavy chain isoforms.

    PubMed Central

    Elluru, R G; Bloom, G S; Brady, S T

    1995-01-01

    The mechanochemical ATPase kinesin is thought to move membrane-bounded organelles along microtubules in fast axonal transport. However, fast transport includes several classes of organelles moving at rates that differ by an order of magnitude. Further, the fact that cytoplasmic forms of kinesin exist suggests that kinesins might move cytoplasmic structures such as the cytoskeleton. To define cellular roles for kinesin, the axonal transport of kinesin was characterized. Retinal proteins were pulse-labeled, and movement of radiolabeled kinesin through optic nerve and tract into the terminals was monitored by immunoprecipitation. Heavy and light chains of kinesin appeared in nerve and tract at times consistent with fast transport. Little or no kinesin moved with slow axonal transport indicating that effectively all axonal kinesin is associated with membranous organelles. Both kinesin heavy chain molecular weight variants of 130,000 and 124,000 M(r) (KHC-A and KHC-B) moved in fast anterograde transport, but KHC-A moved at 5-6 times the rate of KHC-B. KHC-A cotransported with the synaptic vesicle marker synaptophysin, while a portion of KHC-B cotransported with the mitochondrial marker hexokinase. These results suggest that KHC-A is enriched on small tubulovesicular structures like synaptic vesicles and that at least one form of KHC-B is predominantly on mitochondria. Biochemical specialization may target kinesins to appropriate organelles and facilitate differential regulation of transport. Images PMID:7538359

  11. Characterizing Critical Gradient Threshold for Alfvén Eigenmode Induced Fast-Ion Transport

    NASA Astrophysics Data System (ADS)

    Collins, C. S.; Heidbrink, W. W.; Stagner, L.; van Zeeland, M. A.; Pace, D. C.; Petty, C. C.

    2015-11-01

    Recent experiments on DIII-D indicate a sudden increase in fast-ion transport in the presence of many simultaneous Alfvén eigenmodes (AEs) at a threshold in neutral beam power. The threshold is beyond the AE linear stability limit and appears to differ between various fast-ion diagnostics, indicating phase-space dependent transport. Above threshold, transport becomes stiff, resulting in virtually unchanged fast-ion density profiles despite increased beam drive. In the experiment, a beam power scan (2-9 MW) varies AE activity, while the fast-ion pressure profile is modulated using an off-axis neutral beam. Measurements of the fast-ion density evolution are used to infer flux. Fast-ion D α (FIDA) spectroscopy indicates the peak of the modulated fast-ion flux is localized to mid-core radii, corresponding to the radial location of AEs. These measurements facilitate numerical model validation studies, giving greater confidence in predicting the fusion alpha density profiles and losses in future burning plasma devices. Work supported by the US DOE under SC-G903402 & DE-FC02-04ER54698.

  12. Simulations of Fuel Assembly and Fast-Electron Transport in Integrated Fast-Ignition Experiments on OMEGA

    NASA Astrophysics Data System (ADS)

    Solodov, A. A.; Theobald, W.; Anderson, K. S.; Shvydky, A.; Epstein, R.; Betti, R.; Myatt, J. F.; Stoeckl, C.; Jarrott, L. C.; McGuffey, C.; Qiao, B.; Beg, F. N.; Wei, M. S.; Stephens, R. B.

    2013-10-01

    Integrated fast-ignition experiments on OMEGA benefit from improved performance of the OMEGA EP laser, including higher contrast, higher energy, and a smaller focus. Recent 8-keV, Cu-Kα flash radiography of cone-in-shell implosions and cone-tip breakout measurements showed good agreement with the 2-D radiation-hydrodynamic simulations using the code DRACO. DRACO simulations show that the fuel assembly can be further improved by optimizing the compression laser pulse, evacuating air from the shell, and by adjusting the material of the cone tip. This is found to delay the cone-tip breakout by ~220 ps and increase the core areal density from ~80 mg/cm2 in the current experiments to ~500 mg/cm2 at the time of the OMEGA EP beam arrival before the cone-tip breakout. Simulations using the code LSP of fast-electron transport in the recent integrated OMEGA experiments with Cu-doped shells will be presented. Cu-doping is added to probe the transport of fast electrons via their induced Cu K-shell fluorescent emission. This material is based upon work supported by the Department of Energy National Nuclear Security Administration DE-NA0001944 and the Office of Science under DE-FC02-04ER54789.

  13. On the Criticality Safety of Transuranic Sodium Fast Reactor Fuel Transport Casks

    SciTech Connect

    Samuel Bays; Ayodeji Alajo

    2010-05-01

    This work addresses the neutronic performance and criticality safety issues of transport casks for fuel pertaining to low conversion ratio sodium cooled fast reactors, conventionally known as Advanced Burner Reactors. The criticality of a one, three, seven and 19-assembly cask capacity is presented. Both dry “helium” and flooded “water” filled casks are considered. No credit for fuel burnup or fission products was assumed. As many as possible of the conservatisms used in licensing light water reactor universal transport casks were incorporated into this SFR cask criticality design and analysis. It was found that at 7-assemblies or more, adding moderator to the SFR cask increases criticality margin. Also, removal of MAs from the fuel increases criticality margin of dry casks and takes a slight amount of margin away for wet casks. Assuming credit for borated fuel tube liners, this design analysis suggests that as many as 19 assemblies can be loaded in a cask if limited purely by criticality safety. If no credit for boron is assumed, the cask could possibly hold seven assemblies if low conversion ratio fast reactor grade fuel and not breeder reactor grade fuel is assumed. The analysis showed that there is a need for new cask designs for fast reactors spent fuel transportation. There is a potential of modifying existing transportation cask design as the starting point for fast reactor spent fuel transportation.

  14. In vitro low frequency electromagnetic field effect on fast axonal transport.

    PubMed

    Zborowski, M; Atkinson, M; Lewandowski, J J; Jacobs, G; Mitchell, D; Breuer, A C; Nosé, Y

    1988-01-01

    The objective of this study was to evaluate the effects of a low frequency electromagnetic field on fast axonal transport for future neuroprosthetic applications. Changes in speeds and densities of retrograde fast organelle transport in rat sciatic nerve preparations were measured in vitro upon exposure to 15 and 50 Hz pulsed magnetic fields with peak intensities of 4.4 and 8.8 mT. Maximum current density of the induced eddy current was calculated to be about 40 microA/cm2. Video enhanced differential interference contrast microscopy was used to record axons supporting active organelle transport. Strong effects were observed in myelinated axons (cessation of transport in up to 10 min). Such effects may eventually be used as part of a neuroprosthesis to noninvasively modify or couple to various parts of the nervous system.

  15. Tissue-specific expression of monocarboxylate transporters during fasting in mice.

    PubMed

    Schutkowski, Alexandra; Wege, Nicole; Stangl, Gabriele I; König, Bettina

    2014-01-01

    Monocarboxylates such as pyruvate, lactate and ketone bodies are crucial for energy supply of all tissues, especially during energy restriction. The transport of monocarboxylates across the plasma membrane of cells is mediated by monocarboxylate transporters (MCTs). Out of 14 known mammalian MCTs, six isoforms have been functionally characterized to transport monocarboxylates and short chain fatty acids (MCT1-4), thyroid hormones (MCT8, -10) and aromatic amino acids (MCT10). Knowledge on the regulation of the different MCT isoforms is rare. In an attempt to get more insights in regulation of MCT expression upon energy deprivation, we carried out a comprehensive analysis of tissue specific expression of five MCT isoforms upon 48 h of fasting in mice. Due to the crucial role of peroxisome proliferator-activated receptor (PPAR)-α as a central regulator of energy metabolism and as known regulator of MCT1 expression, we included both wildtype (WT) and PPARα knockout (KO) mice in our study. Liver, kidney, heart, small intestine, hypothalamus, pituitary gland and thyroid gland of the mice were analyzed. Here we show that the expression of all examined MCT isoforms was markedly altered by fasting compared to feeding. Expression of MCT1, MCT2 and MCT10 was either increased or decreased by fasting dependent on the analyzed tissue. MCT4 and MCT8 were down-regulated by fasting in all examined tissues. However, PPARα appeared to have a minor impact on MCT isoform regulation. Due to the fundamental role of MCTs in transport of energy providing metabolites and hormones involved in the regulation of energy homeostasis, we assumed that the observed fasting-induced adaptations of MCT expression seem to ensure an adequate energy supply of tissues during the fasting state. Since, MCT isoforms 1-4 are also necessary for the cellular uptake of drugs, the fasting-induced modifications of MCT expression have to be considered in future clinical care algorithms. PMID:25390336

  16. Energetic-particle-driven instabilities and induced fast-ion transport in a reversed field pinch

    SciTech Connect

    Lin, L.; Brower, D. L.; Ding, W. X.; Anderson, J. K.; Capecchi, W.; Eilerman, S.; Forest, C. B.; Koliner, J. J.; Nornberg, M. D.; Reusch, J.; Sarff, J. S.; Liu, D.

    2014-05-15

    Multiple bursty energetic-particle (EP) driven modes with fishbone-like structure are observed during 1 MW tangential neutral-beam injection in a reversed field pinch (RFP) device. The distinguishing features of the RFP, including large magnetic shear (tending to add stability) and weak toroidal magnetic field (leading to stronger drive), provide a complementary environment to tokamak and stellarator configurations for exploring basic understanding of EP instabilities. Detailed measurements of the EP mode characteristics and temporal-spatial dynamics reveal their influence on fast ion transport. Density fluctuations exhibit a dynamically evolving, inboard-outboard asymmetric spatial structure that peaks in the core where fast ions reside. The measured mode frequencies are close to the computed shear Alfvén frequency, a feature consistent with continuum modes destabilized by strong drive. The frequency pattern of the dominant mode depends on the fast-ion species. Multiple frequencies occur with deuterium fast ions compared to single frequency for hydrogen fast ions. Furthermore, as the safety factor (q) decreases, the toroidal mode number of the dominant EP mode transits from n=5 to n=6 while retaining the same poloidal mode number m=1. The transition occurs when the m=1, n=5 wave-particle resonance condition cannot be satisfied as the fast-ion safety factor (q{sub fi}) decreases. The fast-ion temporal dynamics, measured by a neutral particle analyzer, resemble a classical predator-prey relaxation oscillation. It contains a slow-growth phase arising from the beam fueling followed by a rapid drop when the EP modes peak, indicating that the fluctuation-induced transport maintains a stiff fast-ion density profile. The inferred transport rate is strongly enhanced with the onset of multiple EP modes.

  17. A fluctuation-induced plasma transport diagnostic based upon fast-Fourier transform spectral analysis

    NASA Technical Reports Server (NTRS)

    Powers, E. J.; Kim, Y. C.; Hong, J. Y.; Roth, J. R.; Krawczonek, W. M.

    1978-01-01

    A diagnostic, based on fast Fourier-transform spectral analysis techniques, that provides experimental insight into the relationship between the experimentally observable spectral characteristics of the fluctuations and the fluctuation-induced plasma transport is described. The model upon which the diagnostic technique is based and its experimental implementation is discussed. Some characteristic results obtained during the course of an experimental study of fluctuation-induced transport in the electric field dominated NASA Lewis bumpy torus plasma are presented.

  18. MCNPX Monte Carlo simulations of particle transport in SiC semiconductor detectors of fast neutrons

    NASA Astrophysics Data System (ADS)

    Sedlačková, K.; Zat'ko, B.; Šagátová, A.; Pavlovič, M.; Nečas, V.; Stacho, M.

    2014-05-01

    The aim of this paper was to investigate particle transport properties of a fast neutron detector based on silicon carbide. MCNPX (Monte Carlo N-Particle eXtended) code was used in our study because it allows seamless particle transport, thus not only interacting neutrons can be inspected but also secondary particles can be banked for subsequent transport. Modelling of the fast-neutron response of a SiC detector was carried out for fast neutrons produced by 239Pu-Be source with the mean energy of about 4.3 MeV. Using the MCNPX code, the following quantities have been calculated: secondary particle flux densities, reaction rates of elastic/inelastic scattering and other nuclear reactions, distribution of residual ions, deposited energy and energy distribution of pulses. The values of reaction rates calculated for different types of reactions and resulting energy deposition values showed that the incident neutrons transfer part of the carried energy predominantly via elastic scattering on silicon and carbon atoms. Other fast-neutron induced reactions include inelastic scattering and nuclear reactions followed by production of α-particles and protons. Silicon and carbon recoil atoms, α-particles and protons are charged particles which contribute to the detector response. It was demonstrated that although the bare SiC material can register fast neutrons directly, its detection efficiency can be enlarged if it is covered by an appropriate conversion layer. Comparison of the simulation results with experimental data was successfully accomplished.

  19. Fast axonal transport of the proteasome complex depends on membrane interaction and molecular motor function.

    PubMed

    Otero, Maria G; Alloatti, Matías; Cromberg, Lucas E; Almenar-Queralt, Angels; Encalada, Sandra E; Pozo Devoto, Victorio M; Bruno, Luciana; Goldstein, Lawrence S B; Falzone, Tomás L

    2014-04-01

    Protein degradation by the ubiquitin-proteasome system in neurons depends on the correct delivery of the proteasome complex. In neurodegenerative diseases, aggregation and accumulation of proteins in axons link transport defects with degradation impairments; however, the transport properties of proteasomes remain unknown. Here, using in vivo experiments, we reveal the fast anterograde transport of assembled and functional 26S proteasome complexes. A high-resolution tracking system to follow fluorescent proteasomes revealed three types of motion: actively driven proteasome axonal transport, diffusive behavior in a viscoelastic axonema and proteasome-confined motion. We show that active proteasome transport depends on motor function because knockdown of the KIF5B motor subunit resulted in impairment of the anterograde proteasome flux and the density of segmental velocities. Finally, we reveal that neuronal proteasomes interact with intracellular membranes and identify the coordinated transport of fluorescent proteasomes with synaptic precursor vesicles, Golgi-derived vesicles, lysosomes and mitochondria. Taken together, our results reveal fast axonal transport as a new mechanism of proteasome delivery that depends on membrane cargo 'hitch-hiking' and the function of molecular motors. We further hypothesize that defects in proteasome transport could promote abnormal protein clearance in neurodegenerative diseases.

  20. Energetic-particle-driven instabilities and induced fast-ion transport in a reversed field pinch

    NASA Astrophysics Data System (ADS)

    Lin, Liang

    2013-10-01

    Multiple bursty energetic-particle (EP) modes with fishbone-like structures are observed during 1 MW tangential neutral-beam injection into MST reversed field pinch (RFP) plasmas. The distinguishing features of the RFP, including large magnetic shear (tending to add stability) and weak toroidal magnetic field (leading to large fast ion beta and stronger drive), provide a complementary environment to tokamak and stellarator configurations for exploring basic understanding of these instabilities. Detailed measurements of the EP mode characteristics and temporal-spatial dynamics reveal their influence on fast ion transport and interaction with global tearing modes. Internal magnetic field fluctuations associated with the EP modes are directly observed for the first time by Faraday-effect polarimetry (frequency ~ 90 kHz and amplitude ~ 2 G). Simultaneously measured density fluctuations exhibit a dynamically evolving and asymmetric spatial structure that peaks near the core where fast ions reside and shifts outward as the instability evolves. Furthermore, the EP mode frequencies appear at ~k∥VA , consistent with continuum modes destabilized by strong drive. The fast-ion temporal dynamics, measured by a neutral particle analyzer, resemble a classical predator-prey relaxation oscillation. It contains a slow-growing phase arising from the beam fueling followed by a rapid drop (~ 15 %) when the EP modes peak, indicating the fluctuation-induced transport maintains a stiff fast-ion density profile. The inferred transport rate is strongly enhanced (× 2) with the onset of multiple nonlinearly-interacting EP modes. The fast ions also impact global tearing modes, reducing their amplitudes by up to 65%. This mode reduction is lessened following the EP-bursts, further evidence for fast ion redistribution that weakens the suppression mechanism. Possible tearing mode suppression mechanisms will be discussed. Work supported by US DoE.

  1. Measurements of fast-ion transport by mode-particle resonances on DIII-D

    NASA Astrophysics Data System (ADS)

    Muscatello, C. M.; Grierson, B. A.; Harvey, R. W.; Heidbrink, W. W.; Pace, D. C.; Van Zeeland, M. A.

    2012-10-01

    Magnetohydrodynamic (MHD) instabilities in tokamak plasmas manifest in a variety of ways, characterized by different scale lengths and mode frequencies. MHD activity can cause significant degradation of plasma performance due to transport of particles, energy and current. Among the many different types of MHD, arguably fishbones, sawteeth and Alfvén eigenmodes (AEs) are observed to cause the largest fluxes of superthermal ions. DIII-D's expansive suite of diagnostics makes it possible to rigorously characterize these instabilities and study their interaction with fast ions. This review paper first presents an overview of the recent additions to DIII-D's collection of fast-ion diagnostics. The extended diagnostic capabilities are employed in a series of experiments to investigate fast-ion dynamics in the presence of fishbones, sawteeth and AEs. Results from these seemingly unrelated studies are highlighted, and they reveal that mode-particle resonances play the central role in the observed deterioration of fast-ion confinement.

  2. Experimental evidence of electric inhibition in fast electron penetration and of electric-field-limited fast electron transport in dense matter

    PubMed

    Pisani; Bernardinello; Batani; Antonicci; Martinolli; Koenig; Gremillet; Amiranoff; Baton; Davies; Hall; Scott; Norreys; Djaoui; Rousseaux; Fews; Bandulet; Pepin

    2000-11-01

    Fast electron generation and propagation were studied in the interaction of a green laser with solids. The experiment, carried out with the LULI TW laser (350 fs, 15 J), used K(alpha) emission from buried fluorescent layers to measure electron transport. Results for conductors (Al) and insulators (plastic) are compared with simulations: in plastic, inhibition in the propagation of fast electrons is observed, due to electric fields which become the dominant factor in electron transport. PMID:11102017

  3. A monocarboxylate transporter required for hepatocyte secretion of ketone bodies during fasting

    PubMed Central

    Hugo, Sarah E.; Cruz-Garcia, Lourdes; Karanth, Santhosh; Anderson, Ryan M.; Stainier, Didier Y.R.; Schlegel, Amnon

    2012-01-01

    To find new genes that influence liver lipid mass, we performed a genetic screen for zebrafish mutants with hepatic steatosis, a pathological accumulation of fat. The red moon (rmn) mutant develops hepatic steatosis as maternally deposited yolk is depleted. Conversely, hepatic steatosis is suppressed in rmn mutants by adequate nutrition. Adult rmn mutants show increased liver neutral lipids and induction of hepatic lipid biosynthetic genes when fasted. Positional cloning of the rmn locus reveals a loss-of-function mutation in slc16a6a (solute carrier family 16a, member 6a), a gene that we show encodes a transporter of the major ketone body β-hydroxybutyrate. Restoring wild-type zebrafish slc16a6a expression or introducing human SLC16A6 in rmn mutant livers rescues the mutant phenotype. Radiotracer analysis confirms that loss of Slc16a6a function causes diversion of liver-trapped ketogenic precursors into triacylglycerol. Underscoring the importance of Slc16a6a to normal fasting physiology, previously fed rmn mutants are more sensitive to death by starvation than are wild-type larvae. Our unbiased, forward genetic approach has found a heretofore unrecognized critical step in fasting energy metabolism: hepatic ketone body transport. Since β-hydroxybutyrate is both a major fuel and a signaling molecule in fasting, the discovery of this transporter provides a new direction for modulating circulating levels of ketone bodies in metabolic diseases. PMID:22302940

  4. A monocarboxylate transporter required for hepatocyte secretion of ketone bodies during fasting.

    PubMed

    Hugo, Sarah E; Cruz-Garcia, Lourdes; Karanth, Santhosh; Anderson, Ryan M; Stainier, Didier Y R; Schlegel, Amnon

    2012-02-01

    To find new genes that influence liver lipid mass, we performed a genetic screen for zebrafish mutants with hepatic steatosis, a pathological accumulation of fat. The red moon (rmn) mutant develops hepatic steatosis as maternally deposited yolk is depleted. Conversely, hepatic steatosis is suppressed in rmn mutants by adequate nutrition. Adult rmn mutants show increased liver neutral lipids and induction of hepatic lipid biosynthetic genes when fasted. Positional cloning of the rmn locus reveals a loss-of-function mutation in slc16a6a (solute carrier family 16a, member 6a), a gene that we show encodes a transporter of the major ketone body β-hydroxybutyrate. Restoring wild-type zebrafish slc16a6a expression or introducing human SLC16A6 in rmn mutant livers rescues the mutant phenotype. Radiotracer analysis confirms that loss of Slc16a6a function causes diversion of liver-trapped ketogenic precursors into triacylglycerol. Underscoring the importance of Slc16a6a to normal fasting physiology, previously fed rmn mutants are more sensitive to death by starvation than are wild-type larvae. Our unbiased, forward genetic approach has found a heretofore unrecognized critical step in fasting energy metabolism: hepatic ketone body transport. Since β-hydroxybutyrate is both a major fuel and a signaling molecule in fasting, the discovery of this transporter provides a new direction for modulating circulating levels of ketone bodies in metabolic diseases.

  5. Mesoscale Simulation Data for Initializing Fast-Time Wake Transport and Decay Models

    NASA Technical Reports Server (NTRS)

    Ahmad, Nashat N.; Proctor, Fred H.; Vanvalkenburg, Randal L.; Pruis, Mathew J.; LimonDuparcmeur, Fanny M.

    2012-01-01

    The fast-time wake transport and decay models require vertical profiles of crosswinds, potential temperature and the eddy dissipation rate as initial conditions. These inputs are normally obtained from various field sensors. In case of data-denied scenarios or operational use, these initial conditions can be provided by mesoscale model simulations. In this study, the vertical profiles of potential temperature from a mesoscale model were used as initial conditions for the fast-time wake models. The mesoscale model simulations were compared against available observations and the wake model predictions were compared with the Lidar measurements from three wake vortex field experiments.

  6. Transport of fast electrons in a nanowire array with collisional effects included

    SciTech Connect

    Li, Boyuan; Zhang, Zhimeng; Wang, Jian; Zhang, Bo; Zhao, Zongqing; Shan, Lianqiang; Zhou, Weimin; Zhang, Baohan; Cao, Lihua; Gu, Yuqiu

    2015-12-15

    The transport of picosecond laser generated fast electrons in a nanowire array is studied with two-dimensional particle-in-cell simulations. Our simulations show that a fast electron beam is initially guided and collimated by strong magnetic filaments in the array. Subsequently, after the decomposition of the structure of nanowire array due to plasma expansion, the beam is still collimated by the resistive magnetic field. An analytical model is established to give a criterion for long-term beam collimation in a nanowire array; it indicates that the nanowire cell should be wide enough to keep the beam collimated in picosecond scale.

  7. Fast electron transport and heating in ultraintense laser pulse interaction with solid targets

    NASA Astrophysics Data System (ADS)

    Koenig, Michel; Amiranoff, Francois; Baton, Sophie; Gremillet, Laurent; Martinolli, Emanuele; Batani, Dimitri; Bernardinello, Andrea; Greison, Gabriella; Hall, Tom; Rabec Le Gloahec, Marc; Rousseaux, Christophe; Santos, Joao

    2000-10-01

    In the context of the fast electron transport in solid matter and the fast ignitor scheme, we report on results from ultraintense laser pulse interaction with thick targets. Experiments have been performed at LULI with the 100 TW CPA Nd:glass laser, at intensities up to a few 10^19 W/cm^2. Images obtained from classical and chirped-pulse time-resolved reflectometry diagnostics of the back-side target give evidence of the rear surface heating; the geometry and the dynamics of the energy deposition of the relativistic electrons flux into matter are also inferred.

  8. Inhibition of fast axonal transport in vitro by the local anesthetics prilocaine, mepivacaine, and bupivacaine.

    PubMed

    Lavoie, P A

    1983-12-01

    The aim of the present study was to establish the concentrations of prilocaine, mepivacaine, and bupivacaine which are effective at blocking fast axonal transport, to determine whether prilocaine and mepivacaine offer a better prospect of dissociating conduction block and transport block in vivo than does lidocaine and whether bupivacaine offers a better prospect than etidocaine in the same context. Fast axonal transport of [3H]leucine-labeled proteins was studied in vitro in bullfrog spinal nerves and quantitated by liquid scintillation counting. Exposure of spinal nerves to 14 mM prilocaine reduced the quantity of 3H-labeled proteins which accumulated at a ligature by 86%, and exposure to 14 mM mepivacaine reduced it by 70%; 10 mM prilocaine reduced this same parameter by 54%, a degree of inhibition close to the 44% reduction caused by 14 mM lidocaine. The D(-) and L(+) stereoisomers of mepivacaine each reduced transport to the ligature by approximately 50% at a concentration of 14 mM. Bupivacaine reduced the accumulation of 3H-labeled proteins at the ligature by 49% at a 10 mM concentration (pH 6.2); its potency is close to that found for etidocaine in a previous study. Since prilocaine and mepivacaine are at least as potent as lidocaine as transport inhibitors and at blocking impulse conduction, these two anesthetics offer no advantage over lidocaine to achieve dissociation of conduction block from transport block in vivo. Bupivacaine appears to offer no advantage over etidocaine in the same context, as the two agents have a similar potency as local anesthetics and a similar potency as inhibitors of fast axonal transport.

  9. Integrated kinetic simulation of laser-plasma interactions, fast-electron generation, and transport in fast ignition

    SciTech Connect

    Kemp, A. J.; Cohen, B. I.; Divol, L.

    2010-05-15

    We present new results on the physics of short-pulse laser-matter interaction of kilojoule-picosecond pulses at full spatial and temporal scale using a new approach that combines a three-dimensional collisional electromagnetic particle-in-cell code with a magnetohydrodynamic-hybrid model of high-density plasma. In the latter, collisions damp out plasma waves, and an Ohm's law with electron inertia effects neglected determines the electric field. In addition to yielding orders of magnitude in speed-up while avoiding numerical instabilities, this allows us to model the whole problem in a single unified framework: the laser-plasma interaction at subcritical densities, energy deposition at relativistic critical densities, and fast- electron transport in solid densities. Key questions such as the multipicosecond temporal evolution of the laser energy conversion into hot electrons, the impact of return currents on the laser-plasma interaction, and the effect of self-generated electric and magnetic fields on electron transport will be addressed. We will report applications to current experiments.

  10. Integrated Kinetic Simulation of Laser-Plasma Interactions, Fast-Electron Generation and Transport in Fast Ignition

    SciTech Connect

    Kemp, A; Cohen, B; Divol, L

    2009-11-16

    We present new results on the physics of short-pulse laser-matter interaction of kilojoule-picosecond pulses at full spatial and temporal scale, using a new approach that combines a 3D collisional electromagnetic Particle-in-Cell code with an MHD-hybrid model of high-density plasma. In the latter, collisions damp out plasma waves, and an Ohm's law with electron inertia effects neglected determines the electric field. In addition to yielding orders of magnitude in speed-up while avoiding numerical instabilities, this allows us to model the whole problem in a single unified framework: the laser-plasma interaction at sub-critical densities, energy deposition at relativistic critical densities, and fast-electron transport in solid densities. Key questions such as the multi-picosecond temporal evolution of the laser energy conversion into hot electrons, the impact of return currents on the laser-plasma interaction, and the effect of self-generated electric and magnetic fields on electron transport will be addressed. We will report applications to current experiments.

  11. Evidences for and the Models of Fast Nonlocal Transport of Heat in Magnetic Fusion Devices

    NASA Astrophysics Data System (ADS)

    Kukushkin, A. B.; Cherepanov, K. V.

    2009-07-01

    The paper gives a short survey of (i) recent evidences for fast nonlocal transport of the heat in magnetically confined plasmas (above all, the "cold/heat pulse" experiments), (ii) interpretations of such phenomena in terms of nonlocal transport formalisms, based on the dominance of long mean-free-path energy carriers, including the interpretations of "cold pulse" experiments, and gives (iii) quantitative evidence for the domination of nonlocality in the spatial profile of electron cyclotron net radiated power in fusion reactor-grade tokamak (strong toroidal magnetic field, BT>5 T, highly reflecting walls, Rwall>0.5, and hot electron plasma, >10 keV).

  12. PIC modeling of material dependence on fast electron generation and transport

    NASA Astrophysics Data System (ADS)

    Mishra, R.; Wei, M. S.; Chawla, S.; Sentoku, Y.; Stephens, R. B.; Beg, F. N.

    2011-10-01

    2D collisional PIC simulations, using PICLS code that includes dynamic ionization and radiation cooling, are performed to model a recent experiment on the Titan laser using multi-foil targets, where 2x reduction in total fast electron flux and a smaller spot size through high-Z layer were observed. Modeling show that a thin high-Z transport layer (e.g., Au) near lower Z source layer introduces a collimating effect on fast electron transport. Strong self-generated resistive B-fields are produced inside Au layer and at the interface (Al/Au), which confine the fast electron propagation and can also trap electrons in wing region to inhibit their propagation. In addition, effects of the surface material on LPI produced fast electron source characteristics are examined in both planar and buried cone geometries. Supported by US DOE under contracts DE-AC52 07NA27344(ACE) and DE-FC02-04ER54789 (FSC).

  13. Fast Monte Carlo Electron-Photon Transport Method and Application in Accurate Radiotherapy

    NASA Astrophysics Data System (ADS)

    Hao, Lijuan; Sun, Guangyao; Zheng, Huaqing; Song, Jing; Chen, Zhenping; Li, Gui

    2014-06-01

    Monte Carlo (MC) method is the most accurate computational method for dose calculation, but its wide application on clinical accurate radiotherapy is hindered due to its poor speed of converging and long computation time. In the MC dose calculation research, the main task is to speed up computation while high precision is maintained. The purpose of this paper is to enhance the calculation speed of MC method for electron-photon transport with high precision and ultimately to reduce the accurate radiotherapy dose calculation time based on normal computer to the level of several hours, which meets the requirement of clinical dose verification. Based on the existing Super Monte Carlo Simulation Program (SuperMC), developed by FDS Team, a fast MC method for electron-photon coupled transport was presented with focus on two aspects: firstly, through simplifying and optimizing the physical model of the electron-photon transport, the calculation speed was increased with slightly reduction of calculation accuracy; secondly, using a variety of MC calculation acceleration methods, for example, taking use of obtained information in previous calculations to avoid repeat simulation of particles with identical history; applying proper variance reduction techniques to accelerate MC method convergence rate, etc. The fast MC method was tested by a lot of simple physical models and clinical cases included nasopharyngeal carcinoma, peripheral lung tumor, cervical carcinoma, etc. The result shows that the fast MC method for electron-photon transport was fast enough to meet the requirement of clinical accurate radiotherapy dose verification. Later, the method will be applied to the Accurate/Advanced Radiation Therapy System ARTS as a MC dose verification module.

  14. Transport simulation and image reconstruction for fast-neutron detection of explosives and narcotics

    NASA Astrophysics Data System (ADS)

    Micklich, Bradley J.; Fink, Charles L.; Sagalovsky, Leonid

    1995-09-01

    Fast-neutron inspection techniques show considerable promise for explosive and narcotics detection. A key advantage of using fast neutron is their sensitivity to low-Z elements (carbon, nitrogen, and oxygen), which are the primary constituents of these materials. We are currently investigating two interrogation methods in detail: fast-neutron transmission spectroscopy (FNTS) and pulsed fast-neutron analysis (PFNA). FNTS is being studied for explosives and narcotics detection in luggage and small containers for which the transmission ration is greater than about 0.01. The Monte Carlo radiation transport code MCNP is being used to simulate neutron transmission through a series of phantoms for a few (3-5) projections angles and modest (2 cm) reolution. Areal densities along projection rays are unfolded from the transmission data. Elemental abundances are obtained for individual voxels by tomographic reconstruction, and the reconstructed elemental images are combined to provide indications of the presence or absence of explosives or narcotics. PFNA techniques are being investigated for detection of narcotics in cargo containers because of the good penetration of the fast neutrons and the low attenuation of the resulting high-energy gamma-ray signatures. Analytic models and Monte Carlo simulations are being used to explore the range of capabilities of PFNA techniques and to provide insight into systems engineering issues. Results of studies from both FNTS and PFNA technqiues are presented.

  15. Transport simulation and image reconstruction for fast-neutron detection of explosives and narcotics

    SciTech Connect

    Micklich, B.J.; Fink, C.L.; Sagalovsky, L.

    1995-07-01

    Fast-neutron inspection techniques show considerable promise for explosive and narcotics detection. A key advantage of using fast neutrons is their sensitivity to low-Z elements (carbon, nitrogen, and oxygen), which are the primary constituents of these materials. We are currently investigating two interrogation methods in detail: Fast-Neutron Transmission Spectroscopy (FNTS) and Pulsed Fast-Neutron Analysis (PFNA). FNTS is being studied for explosives and narcotics detection in luggage and small containers for which the transmission ratio is greater than about 0.01. The Monte-Carlo radiation transport code MCNP is being used to simulate neutron transmission through a series of phantoms for a few (3-5) projection angles and modest (2 cm) resolution. Areal densities along projection rays are unfolded from the transmission data. Elemental abundances are obtained for individual voxels by tomographic reconstruction, and these reconstructed elemental images are combined to provide indications of the presence or absence of explosives or narcotics. PFNA techniques are being investigated for detection of narcotics in cargo containers because of the good penetration of the fast neutrons and the low attenuation of the resulting high-energy gamma-ray signatures. Analytic models and Monte-Carlo simulations are being used to explore the range of capabilities of PFNA techniques and to provide insight into systems engineering issues. Results of studies from both FNTS and PFNA techniques are presented.

  16. Electron Generation and Transport in Intense Relativistic Laser-Plasma Interactions Relevant to Fast Ignition ICF

    SciTech Connect

    Ma, Tammy Yee Wing

    2010-01-01

    The reentrant cone approach to Fast Ignition, an advanced Inertial Confinement Fusion scheme, remains one of the most attractive because of the potential to efficiently collect and guide the laser light into the cone tip and direct energetic electrons into the high density core of the fuel. However, in the presence of a preformed plasma, the laser energy is largely absorbed before it can reach the cone tip. Full scale fast ignition laser systems are envisioned to have prepulses ranging between 100 mJ to 1 J. A few of the imperative issues facing fast ignition, then, are the conversion efficiency with which the laser light is converted to hot electrons, the subsequent transport characteristics of those electrons, and requirements for maximum allowable prepulse this may put on the laser system. This dissertation examines the laser-to-fast electron conversion efficiency scaling with prepulse for cone-guided fast ignition. Work in developing an extreme ultraviolet imager diagnostic for the temperature measurements of electron-heated targets, as well as the validation of the use of a thin wire for simultaneous determination of electron number density and electron temperature will be discussed.

  17. Carbon transport in a bimetallic sodium loop simulating the intermediate heat transport system of a liquid metal fast breeder reactor

    SciTech Connect

    Hampton, L.V.; Spalaris, C.N.; Roy, P.

    1980-04-01

    Carbon transport data from a bimetallic sodium loop simulating the intermediate heat transport system of a Liquid Metal Fast Breeder Reactor are discussed. The results of bulk carbon analyses after 15,000 hours' exposure indicate a pattern of carburization of Type 304 stainless steel foils which is independent of loop sodium temperature. A model based on carbon activity gradients accounting for this behavior is proposed. Data also indicate that carburization of Type 304 stainless steel is a diffusion-controlled process; however, decarburization of the ferritic 2 1/4 Cr-1Mo steel is not. It is proposed that the decarburization of the ferritic steel is controlled by the dissolution of carbides in the steel matrix. The differences in the sodium decarburization behavior of electroslag remelted and vacuum-arc remelted 2 1/4 Cr-1Mo steel are also highlighted.

  18. A fast low-pressure transport route to large black phosphorus single crystals

    SciTech Connect

    Nilges, Tom Kersting, Marcel; Pfeifer, Thorben

    2008-08-15

    Black phosphorus, a promising candidate for lithium battery electrodes, can be prepared by a low-pressure transport reaction route representing the first effective and scalable access to this element modification. Crystal sizes larger than 1 cm were obtained at low-pressure conditions in silica ampoules. X-ray phase analyses, EDX, ICP-MS and optical microscopy were applied to characterize the resulting black phosphorus. The present method drastically improves the traditional preparation ways like mercury catalysis, bismuth-flux or high-pressure techniques and represents an easy, non-toxic, fast and highly efficient method to achieve black phosphorus. In contrast to a previously reported low-pressure route the present transport reaction allows an up-scaling to higher masses of starting materials, a larger black phosphorus yield and faster reaction time under retention of the high product crystallinity. - Graphical abstract: A low-pressure transport reaction route representing the first effective and scalable access to black phosphorus.

  19. Observation of Critical-Gradient Behavior in Alfvén-Eigenmode-Induced Fast-Ion Transport.

    PubMed

    Collins, C S; Heidbrink, W W; Austin, M E; Kramer, G J; Pace, D C; Petty, C C; Stagner, L; Van Zeeland, M A; White, R B; Zhu, Y B

    2016-03-01

    Experiments in the DIII-D tokamak show that fast-ion transport suddenly becomes stiff above a critical threshold in the presence of many overlapping small-amplitude Alfvén eigenmodes (AEs). The threshold is phase-space dependent and occurs when particle orbits become stochastic due to resonances with AEs. Above threshold, equilibrium fast-ion density profiles are unchanged despite increased drive, and intermittent fast-ion losses are observed. Fast-ion Dα spectroscopy indicates radially localized transport of the copassing population at radii that correspond to the location of midcore AEs. The observation of stiff fast-ion transport suggests that reduced models can be used to effectively predict alpha profiles, beam ion profiles, and losses to aid in the design of optimized scenarios for future burning plasma devices.

  20. Observation of Critical-Gradient Behavior in Alfvén-Eigenmode-Induced Fast-Ion Transport

    NASA Astrophysics Data System (ADS)

    Collins, C. S.; Heidbrink, W. W.; Austin, M. E.; Kramer, G. J.; Pace, D. C.; Petty, C. C.; Stagner, L.; Van Zeeland, M. A.; White, R. B.; Zhu, Y. B.

    2016-03-01

    Experiments in the DIII-D tokamak show that fast-ion transport suddenly becomes stiff above a critical threshold in the presence of many overlapping small-amplitude Alfvén eigenmodes (AEs). The threshold is phase-space dependent and occurs when particle orbits become stochastic due to resonances with AEs. Above threshold, equilibrium fast-ion density profiles are unchanged despite increased drive, and intermittent fast-ion losses are observed. Fast-ion D α spectroscopy indicates radially localized transport of the copassing population at radii that correspond to the location of midcore AEs. The observation of stiff fast-ion transport suggests that reduced models can be used to effectively predict alpha profiles, beam ion profiles, and losses to aid in the design of optimized scenarios for future burning plasma devices.

  1. Measurement of Fast Electron Transport by Lower Hybrid Modulation Experiments in Alcator C-Mod

    SciTech Connect

    Schmidt, A. E.; Bonoli, P. T.; Parker, R.; Porkolab, M.; Wallace, G.; Wright, J. C.; Wilson, J. R.; Harvey, R. W.; Smirnov, A. P.

    2009-11-26

    The Lower Hybrid Current Drive (LHCD) system on Alcator C-Mod can produce spectra with a wide range of peak parallel refractive index (n{sub parallel}). An experiment in which LH power is square-wave modulated on a time scale much faster than the current relaxation time does not significantly alter the poloidal magnetic field inside the plasma and thus allows for realistic modeling and consistent plasma conditions for different ny spectra. Boxcar binning of hard x-rays during LH power modulation allows for time resolution sufficient to resolve the build-up, steady-state, and slowing-down of fast electrons. A transport model built in Matlab has been used to determine a fast electron pinch velocity for a high-n{sub parallel} case of 1-2 m/s.

  2. High effective cytosolic H+ buffering in mouse cortical astrocytes attributable to fast bicarbonate transport.

    PubMed

    Theparambil, Shefeeq M; Deitmer, Joachim W

    2015-09-01

    Cytosolic H(+) buffering plays a major role for shaping intracellular H(+) shifts and hence for the availability of H(+) for biochemical reactions and acid/base-coupled transport processes. H(+) buffering is one of the prime means to protect the cell from large acid/base shifts. We have used the H(+) indicator dye BCECF and confocal microscopy to monitor the cytosolic H(+) concentration, [H(+)]i, in cultured cortical astrocytes of wild-type mice and of mice deficient in sodium/bicarbonate cotransporter NBCe1 (NBCe1-KO) or in carbonic anhydrase isoform II (CAII-KO). The steady-state buffer strength was calculated from the amplitude of [H(+)]i transients as evoked by CO2/HCO3(-) and by butyric acid in the presence and absence of CO2/HCO3(-). We tested the hypotheses if, in addition to instantaneous physicochemical H(+) buffering, rapid acid/base transport across the cell membrane contributes to the total, "effective" cytosolic H(+) buffering. In the presence of 5% CO2/26 mM HCO3(-), H(+) buffer strength in astrocytes was increased 4-6 fold, as compared with that in non-bicarbonate, HEPES-buffered solution, which was largely attributable to fast HCO3 (-) transport into the cells via NBCe1, supported by CAII activity. Our results show that within the time frame of determining physiological H(+) buffering in cells, fast transport and equilibration of CO2/H(+)/HCO3(-) can make a major contribution to the total "effective" H(+) buffer strength. Thus, "effective" cellular H(+) buffering is, to a large extent, attributable to membrane transport of base equivalents rather than a purely passive physicochemical process, and can be much larger than reported so far. Not only physicochemical H(+) buffering, but also rapid import of HCO3(-) via the electrogenic sodium-bicarbonate cotransporter NBCe1, supported by carbonic anhydrase II (CA II), was identified to enhance cytosolic H(+) buffer strength substantially.

  3. Fast Responsive and Controllable Liquid Transport on a Magnetic Fluid/Nanoarray Composite Interface.

    PubMed

    Tian, Dongliang; Zhang, Na; Zheng, Xi; Hou, Guanglei; Tian, Ye; Du, Yi; Jiang, Lei; Dou, Shi Xue

    2016-06-28

    Controllable liquid transport on surface is expected to occur by manipulating the gradient of surface tension/Laplace pressure and external stimuli, which has been intensively studied on solid or liquid interface. However, it still faces challenges of slow response rate, and uncontrollable transport speed and direction. Here, we demonstrate fast responsive and controllable liquid transport on a smart magnetic fluid/nanoarray interface, i.e., a composite interface, via modulation of an external magnetic field. The wettability of the composite interface to water instantaneously responds to gradient magnetic field due to the magnetically driven composite interface gradient roughness transition that takes place within a millisecond, which is at least 1 order of magnitude faster than that of other responsive surfaces. A water droplet can follow the motion of the gradient composite interface structure as it responds to the gradient magnetic field motion. Moreover, the water droplet transport direction can be controlled by modulating the motion direction of the gradient magnetic field. The composite interface can be used as a pump for the transport of immiscible liquids and other objects in the microchannel, which suggests a way to design smart interface materials and microfluidic devices. PMID:27199104

  4. Molecular-Flow Properties of RIB Type Vapor-Transport Systems Using a Fast-Valve

    SciTech Connect

    Alton, Gerald D; Bilheux, Hassina Z; Zhang, Y.; Liu, Yuan

    2014-01-01

    The advent of the fast-valve device, described previously, permits measurement of molecular-flow times of chemically active or inactive gaseous species through radioactive ion beam (RIB) target ion source systems, independent of size, geometry and materials of construction. Thus, decay losses of short-half-life RIBs can be determined for a given target/vapor-transport system in advance of on-line operation, thereby ascertaining the feasibility of the system design for successful processing of a given isotope. In this article, molecular-flow-time theory and experimentally measured molecular-flow time data are given for serial- and parallel-coupled Ta metal RIB vapor-transport systems similar to those used at ISOL based RIB facilities. In addition, the effect of source type on the molecular-flow time properties of a given system is addressed, and a chemical passivation method for negating surface adsorption enthalpies for chemically active gaseous species on Ta surfaces is demonstrated.

  5. Theory of ion transport with fast acid-base equilibrations in bioelectrochemical systems

    NASA Astrophysics Data System (ADS)

    Dykstra, J. E.; Biesheuvel, P. M.; Bruning, H.; Ter Heijne, A.

    2014-07-01

    Bioelectrochemical systems recover valuable components and energy in the form of hydrogen or electricity from aqueous organic streams. We derive a one-dimensional steady-state model for ion transport in a bioelectrochemical system, with the ions subject to diffusional and electrical forces. Since most of the ionic species can undergo acid-base reactions, ion transport is combined in our model with infinitely fast ion acid-base equilibrations. The model describes the current-induced ammonia evaporation and recovery at the cathode side of a bioelectrochemical system that runs on an organic stream containing ammonium ions. We identify that the rate of ammonia evaporation depends not only on the current but also on the flow rate of gas in the cathode chamber, the diffusion of ammonia from the cathode back into the anode chamber, through the ion exchange membrane placed in between, and the membrane charge density.

  6. Theory of ion transport with fast acid-base equilibrations in bioelectrochemical systems.

    PubMed

    Dykstra, J E; Biesheuvel, P M; Bruning, H; Ter Heijne, A

    2014-07-01

    Bioelectrochemical systems recover valuable components and energy in the form of hydrogen or electricity from aqueous organic streams. We derive a one-dimensional steady-state model for ion transport in a bioelectrochemical system, with the ions subject to diffusional and electrical forces. Since most of the ionic species can undergo acid-base reactions, ion transport is combined in our model with infinitely fast ion acid-base equilibrations. The model describes the current-induced ammonia evaporation and recovery at the cathode side of a bioelectrochemical system that runs on an organic stream containing ammonium ions. We identify that the rate of ammonia evaporation depends not only on the current but also on the flow rate of gas in the cathode chamber, the diffusion of ammonia from the cathode back into the anode chamber, through the ion exchange membrane placed in between, and the membrane charge density. PMID:25122405

  7. Fast strontium transport induced by hydrodynamic dispersion and pH-dependent sorption

    NASA Astrophysics Data System (ADS)

    Prigiobbe, Valentina; Hesse, Marc A.; Bryant, Steven L.

    2012-09-01

    As a fluid carries solutes through a porous material, species that sorb onto the surface of the material travel more slowly than the fluid. Stronger adsorption results in slower solute migration, or increased solute retardation. The adsorption of strontium (Sr2+) onto iron-oxides is strongly pH-dependent and becomes significant at high pH. Radioactive Sr2+ isotopes are, therefore, commonly stored in alkaline solutions to maximize their retardation. Field observations and numerical simulations of the leakage of such solutions into low-pH soils, however, show that even Sr2+ stored in alkaline solutions can migrate without retardation. Migration occurs because hydrodynamic dispersion allows mixing of Sr2+ with the low-pH fluid forming an acidic Sr2+-rich plume which can travel without retardation. Here we report the first experimental observations confirming this dispersion-induced fast Sr2+ transport. We report column-flood experiments where a high-pH solution containing Sr2+ was injected into a low-pH porous medium of iron-oxide-coated beads. We observe both a strongly retarded Sr2+ front and an isolated fast pulse of Sr2+ traveling at the average fluid velocity. This dispersion-induced fast pulse of strontium must be taken into account when considering the safety of radionuclide storage in alkaline solutions.

  8. Alfv?nic Instabilities and Fast Ion Transport in the DIII-D Tokamak

    SciTech Connect

    Van Zeeland, M; Heidbrink, W; Nazikian, R; Austin, M; Berk, H; Gorelenkov, N; Holcomb, C; Kramer, G; Lohr, J; Luo, Y; Makowski, M; McKee, G; Petty, C; Prater, R; Solomon, W; White, R

    2008-10-14

    Neutral beam injection into reversed magnetic shear DIII-D plasmas produces a variety of Alfvenic activity including Toroidicity and Ellipticity induced Alfven Eigenmodes (TAE/EAE, respectively) and Reversed Shear Alfven Eigenmodes (RSAE) as well as their spatial coupling. These modes are typically studied during the discharge current ramp phase when incomplete current penetration results in a high central safety factor and strong drive due to multiple higher order resonances. During this same time period Fast-Ion D{sub {alpha}} (FIDA) spectroscopy shows that the central fast ion profile is flattened, the degree of which depends on the Alfven eigenmode amplitude. Interestingly, localized electron cyclotron heating (ECH) near the mode location stabilizes RSAE activity and results in significantly improved fast ion confinement relative to discharges with ECH deposition on axis. In these discharges, RSAE activity is suppressed when ECH is deposited near the radius of the shear reversal point and enhanced with deposition near the axis. To simulate the observed neutral beam ion redistribution, NOVA calculations of the 3D eigenmode structures are matched with experimental measurements and used in combination with the ORBIT guiding center following code. For fixed frequency eigenmodes, it is found that ORBIT calculations cannot explain the observed beam ion transport with experimentally measured mode amplitudes. Possible explanations are considered including recent simulation results incorporating eigenmodes with time dependent frequencies.

  9. Modeling fast-ion transport during toroidal Alfven eigenmode avalanches in National Spherical Torus Experiment

    SciTech Connect

    Fredrickson, E. D.; Bell, R. E.; Darrow, D. S.; Gorelenkov, N. N.; Kramer, G. J.; Medley, S. S.; White, R. B.; Crocker, N. A.; Kubota, S.; Levinton, F. M.; Yuh, H.; Liu, D.; Podesta, M.; Tritz, K.

    2009-12-15

    Experiments on the National Spherical Torus Experiment [M. Ono et al., Nucl. Fusion 40, 557 (2000)] found strong bursts of toroidal Alfven eigenmode (TAE) activity correlated with abrupt drops in the neutron rate. A fairly complete data set offers the opportunity to benchmark the NOVA[C. Z. Cheng, Phys. Rep. 211, 1 (1992)] and ORBIT[R. B. White and M. S. Chance, Phys. Fluids 27, 2455 (1984)] codes in the low aspect ratio tokamak (ST) geometry. The internal structure of TAE was modeled with NOVA and good agreement is found with measurements made with an array of five fixed-frequency reflectometers. The fast-ion transport resulting from these bursts of multiple TAE was then modeled with the ORBIT code. The simulations are reasonably consistent with the observed drop in neutron rate, however, further refinements in both the simulation of the TAE structure and in the modeling of the fast-ion transport are needed. Benchmarking stability codes against present experiments is an important step in developing the predictive capability needed to plan future experiments.

  10. Generation and Transport of Fast Electrons in Laser Irradiated Targets at Relativistic Intensities

    NASA Astrophysics Data System (ADS)

    Amiranoff, F.; Baton, S. D.; Gremillet, L.; Guilbaud, O.; Koenig, M.; Martinolli, E.; Santos, J. J.; Le Gloahec, M. Rabec; Rousseaux, C.; Hall, T.

    2002-10-01

    The transport of relativistic electrons in solid targets irradiated by a short laser pulse at relativistic intensities has been studied both experimentally and numerically. A Monte-Carlo collision code takes into account individual collisions with the ions and electrons in the target. A 3D-hybrid code takes into account these collisions as well as the generation of electric and magnetic fields and the self-consistent motion of the electrons in these fields. It predicts a magnetic guiding of a fraction of the fast electron current over long distances and a localized heating of the material along the propagation axis. In experiments performed at LULI on the 100 TW laser facility, several diagnostics have been implemented to diagnose the geometry of the fast electron transport and the target heating. The typical conditions were: E1 less-than-or-equal 20 J, lambda = 1 mum, tau approximately 300 fs, I approximately 1018-5.1019W/cm2. The results indicate a modest heating of the target (typically 20-40 eV over 20 mum to 50 mum), consistent with an acceleration of the electrons inside a wide aperture cone along the laser axis.

  11. Fasting induces basolateral uptake transporters of the SLC family in the liver via HNF4alpha and PGC1alpha.

    PubMed

    Dietrich, Christoph G; Martin, Ina V; Porn, Anne C; Voigt, Sebastian; Gartung, Carsten; Trautwein, Christian; Geier, Andreas

    2007-09-01

    Fasting induces numerous adaptive changes in metabolism by several central signaling pathways, the most important represented by the HNF4alpha/PGC-1alpha-pathway. Because HNF4alpha has been identified as central regulator of basolateral bile acid transporters and a previous study reports increased basolateral bile acid uptake into the liver during fasting, we hypothesized that HNF4alpha is involved in fasting-induced bile acid uptake via upregulation of basolateral bile acid transporters. In rats, mRNA of Ntcp, Oatp1, and Oatp2 were significantly increased after 48 h of fasting. Protein expression as determined by Western blot showed significant increases for all three transporters 72 h after the onset of fasting. Whereas binding activity of HNF1alpha in electrophoretic mobility shift assays remained unchanged, HNF4alpha binding activity to the Ntcp promoter was increased significantly. In line with this result, we found significantly increased mRNA expression of HNF4alpha and PGC-1alpha. Functional studies in HepG2 cells revealed an increased endogenous NTCP mRNA expression upon cotransfection with either HNF4alpha, PGC-1alpha, or a combination of both. We conclude that upregulation of the basolateral bile acid transporters Ntcp, Oatp1, and Oatp2 in fasted rats is mediated via the HNF4alpha/PGC-1alpha pathway. PMID:17640976

  12. Fasting induces basolateral uptake transporters of the SLC family in the liver via HNF4alpha and PGC1alpha.

    PubMed

    Dietrich, Christoph G; Martin, Ina V; Porn, Anne C; Voigt, Sebastian; Gartung, Carsten; Trautwein, Christian; Geier, Andreas

    2007-09-01

    Fasting induces numerous adaptive changes in metabolism by several central signaling pathways, the most important represented by the HNF4alpha/PGC-1alpha-pathway. Because HNF4alpha has been identified as central regulator of basolateral bile acid transporters and a previous study reports increased basolateral bile acid uptake into the liver during fasting, we hypothesized that HNF4alpha is involved in fasting-induced bile acid uptake via upregulation of basolateral bile acid transporters. In rats, mRNA of Ntcp, Oatp1, and Oatp2 were significantly increased after 48 h of fasting. Protein expression as determined by Western blot showed significant increases for all three transporters 72 h after the onset of fasting. Whereas binding activity of HNF1alpha in electrophoretic mobility shift assays remained unchanged, HNF4alpha binding activity to the Ntcp promoter was increased significantly. In line with this result, we found significantly increased mRNA expression of HNF4alpha and PGC-1alpha. Functional studies in HepG2 cells revealed an increased endogenous NTCP mRNA expression upon cotransfection with either HNF4alpha, PGC-1alpha, or a combination of both. We conclude that upregulation of the basolateral bile acid transporters Ntcp, Oatp1, and Oatp2 in fasted rats is mediated via the HNF4alpha/PGC-1alpha pathway.

  13. Fast axonal transport in isolated axoplasm from the squid giant axon.

    PubMed

    Song, Yuyu; Kang, Minsu; Morfini, Gerardo; Brady, Scott T

    2016-01-01

    The giant axon of the squid provides a unique cell biological model for analyzing the biochemistry and cell biology of the axon. These axons may exceed 500 μm in diameter and can be readily dissected. Once the surrounding small axons and connective tissue are removed, the axoplasm can be extruded as an intact cylinder of isolated cytoplasm. This isolated axoplasm is morphologically indistinguishable from the intact axon, but without permeability barriers. Fast axonal transport will continue for more than 4 h after extrusion and can be visualized in real time. By perfusing defined concentrations of proteins and/or reagents into the axoplasm, this preparation represents a powerful model for study of intracellular trafficking and its underlying molecular mechanisms.

  14. Cadmium transport through molten salts in the reprocessing of spent fuel for the integral fast reactor

    SciTech Connect

    Goff, K.M.; Schneider, A. ); Battles, J.E. )

    1993-06-01

    The reprocessing of spent fuel from the Integral Fast Reactor is to be accomplished with a pyrochemical process employing molten LiCl-KCl salt covering a pool of cadmium. An examination of this system demonstrates that cadmium metal is soluble to a small extent in this salt and that it diffuses through the salt covering and vaporizes at the surface. The cadmium is soluble in the salt because of either chemical or physical solubility, both of which are dependent on the salt's surface tension. Mixing increases the vaporization rate of the cadmium by increasing its transport to the salt surface. The cadmium vapors can therefore be reduced by decreasing the mixing conditions, by choosing a salt with a higher surface tension so that the cadmium is less soluble, or by decreasing the temperature of the system, thereby lowering the vapor pressure of the cadmium.

  15. Dependence of fast-ion transport on the nature of the turbulence in the Large Plasma Device

    SciTech Connect

    Zhou Shu; Heidbrink, W. W.; Boehmer, H.; McWilliams, R.; Carter, T. A.; Vincena, S.; Tripathi, S. K. P.

    2011-08-15

    Strong turbulent waves ({delta}n/n {approx}0.5, f {approx}5-40 kHz) are observed in the upgraded Large Plasma Device [W. Gekelman, H. Pfister, Z. Lucky, J. Bamber, D. Leneman, and J. Maggs, Rev. Sci. Instrum. 62, 2875 (1991)] on density gradients produced by an annular obstacle. Energetic lithium ions (E{sub fast}/T{sub i}{>=}300, {rho}{sub fast}/{rho}{sub s}{approx}10) orbit through the turbulent region. Scans with a collimated analyzer and with probes give detailed profiles of the fast ion spatial distribution and of the fluctuating wave fields. The characteristics of the fluctuations are modified by changing the plasma species from helium to neon and by modifying the bias on the obstacle. Different spatial structure sizes (L{sub s}) and correlation lengths (L{sub corr}) of the wave potential fields alter the fast ion transport. The effects of electrostatic fluctuations are reduced due to gyro-averaging, which explains the difference in the fast-ion transport. A transition from super-diffusive to sub-diffusive transport is observed when the fast ion interacts with the waves for most of a wave period, which agrees with theoretical predictions.

  16. Ultra-fast single-file transport of a simple liquid beyond the collective behavior zone.

    PubMed

    Su, Jiaye; Yang, Keda; Huang, Decai

    2016-07-27

    We use molecular dynamics simulations to analyze the single-file transport behavior of a simple liquid through a narrow membrane channel. With the decrease of the liquid-channel interaction, the liquid flow exhibits a remarkable maximum behavior owing to the competition of liquid-liquid and liquid-channel interactions. Surprisingly, this maximum flow is coupled to a sudden reduce of the liquid occupancy, where the liquid particle is moving through the channel alone at nearly constant velocity, rather than in a collective motion mode. Further investigation on the encountered energy barrier suggests that this maximum flow should be induced by particles having large instant velocities (or thermal fluctuation) that overcome the liquid-liquid and liquid-channel interaction barriers. Further decreasing the liquid-channel interaction leads to the decrease and ultimate stabilization of the liquid flow, since the energy barrier will increase and becomes steady. These results suggest that the breakdown of collective behavior can be a new rule for achieving fast single-file transportation, especially for simple or nonpolar liquids with relatively weak liquid-liquid interactions, and is thus helpful for the design of high flux nanofluidic devices.

  17. Does a Critical Gradient Exist for Alfvén Eigenmode Induced Fast-Ion Transport?

    NASA Astrophysics Data System (ADS)

    Collins, C. S.; Heidbrink, W. W.; van Zeeland, M. A.; Petty, C. C.; Pace, D. C.; Grierson, B. A.

    2014-10-01

    In the critical gradient model, if local energetic particle (EP) drive exceeds the Alfvén eigenmode (AE) stability limit, particles diffuse to flatten the pressure profile until marginal stability is maintained. A key signature is a sudden increase in transport above the critical gradient. In DIII-D, the onset of AE-induced EP transport is examined by modulating the EP pressure profile using an off-axis neutral beam while AE activity gradually diminishes during the current ramp. The time evolution of the EP density profile is measured with fast-ion Dα (FIDA) spectroscopy. During quiescent periods, the FIDA intensity rises and decays approximately linearly during and after the beam pulse, whereas during strong AE activity, the modulated FIDA intensity amplitude and decay rate decrease, suggesting additional AE-induced radial diffusion. Hardware upgrades are underway to increase spatial resolution and accommodate the full Dα spectrum, providing better constraints when comparing to predictive models. Work supported by the US Department of Energy under SC-G903402, DE-FC02-04ER54698, and DE-AC02-09CH11466.

  18. Experimental studies on fast-ion transport by Alfven wave avalanches on the National Spherical Torus Experiment

    SciTech Connect

    Podesta, M.; Heidbrink, W. W.; Liu, D.; Ruskov, E.; Bell, R. E.; Darrow, D. S.; Fredrickson, E. D.; Gorelenkov, N. N.; Kramer, G. J.; LeBlanc, B. P.; Medley, S. S.; Roquemore, A. L.; Crocker, N. A.; Kubota, S.; Yuh, H.

    2009-05-15

    Fast-ion transport induced by Alfven eigenmodes (AEs) is studied in beam-heated plasmas on the National Spherical Torus Experiment [Ono et al., Nucl. Fusion 40, 557 (2000)] through space, time, and energy resolved measurements of the fast-ion population. Fast-ion losses associated with multiple toroidicity-induced AEs (TAEs), which interact nonlinearly and terminate in avalanches, are characterized. A depletion of the energy range >20 keV, leading to sudden drops of up to 40% in the neutron rate over 1 ms, is observed over a broad spatial range. It is shown that avalanches lead to a relaxation of the fast-ion profile, which in turn reduces the drive for the instabilities. The measured radial eigenmode structure and frequency of TAEs are compared with the predictions from a linear magnetohydrodynamics stability code. The partial disagreement suggests that nonlinearities may compromise a direct comparison between experiment and linear theory.

  19. Confinement degradation by Alfvén-eigenmode induced fast-ion transport in steady-state scenario discharges

    NASA Astrophysics Data System (ADS)

    Heidbrink, W. W.; Ferron, J. R.; Holcomb, C. T.; Van Zeeland, M. A.; Chen, Xi; Collins, C. M.; Garofalo, A.; Gong, X.; Grierson, B. A.; Podestà, M.; Stagner, L.; Zhu, Y.

    2014-09-01

    Analysis of neutron and fast-ion Dα data from the DIII-D tokamak shows that Alfvén eigenmode activity degrades fast-ion confinement in many high βN, high qmin, steady-state scenario discharges. (βN is the normalized plasma pressure and qmin is the minimum value of the plasma safety factor.) Fast-ion diagnostics that are sensitive to the co-passing population exhibit the largest reduction relative to classical predictions. The increased fast-ion transport in discharges with strong AE activity accounts for the previously observed reduction in global confinement with increasing qmin; however, not all high qmin discharges show appreciable degradation. Two relatively simple empirical quantities provide convenient monitors of these effects: (1) an ‘AE amplitude’ signal based on interferometer measurements and (2) the ratio of the neutron rate to a zero-dimensional classical prediction.

  20. Alfvén Eigenmode Induced Fast Ion Transport in DIII-D Resulting From Finite Larmor Radius Effects

    NASA Astrophysics Data System (ADS)

    Kramer, G. J.; Fu, G. Y.; Nazikian, R.; van Zeeland, M. A.; Fisher, R. K.; Pace, D. C.; Chen, L.; Chen, X.; Heidbrink, W. W.

    2013-10-01

    Alfvén Eigenmode (AE) induced fast-ion redistribution and loss are commonly observed in DIII-D. In those experiments the perpendicular wave vector times the fast-ion Larmor radius is of order unity (k⊥ρi ~ 1), which allows fast ion orbits to traverse the AE mode structures asymmetrically causing a significant change in magnetic moment. Full-orbit simulations of the expected transport in DIII-D plasmas show that this effect can lead to fast-ion radial diffusion constants of 5 m2/s at the measured mode amplitudes. This level of diffusion is not captured with a guiding center approximation and is in agreement with that deduced in DIII-D experiments when AE activity was present. Work supported by the US Department of Energy under DE-AC02-09CH11466, DE-FC02-04ER54698, and SC-G903402.

  1. Fast-ion transport in qmin>2, high- β steady-state scenarios on DIII-D

    DOE PAGESBeta

    Holcomb, C. T.; Heidbrink, W. W.; Ferron, J. R.; Van Zeeland, M. A.; Garofalo, A. M.; Solomon, W. M.; Gong, X.; Mueller, D.; Grierson, B.; Bass, E. M.; et al

    2015-05-22

    The results from experiments on DIII-D [J. L. Luxon, Fusion Sci. Technol. 48, 828 (2005)] aimed at developing high β steady-state operating scenarios with high-qminqmin confirm that fast-ion transport is a critical issue for advanced tokamak development using neutral beam injection current drive. In DIII-D, greater than 11 MW of neutral beam heating power is applied with the intent of maximizing βN and the noninductive current drive. However, in scenarios with qmin>2 that target the typical range of q95= 5–7 used in next-step steady-state reactor models, Alfvén eigenmodes cause greater fast-ion transport than classical models predict. This enhanced transport reducesmore » the absorbed neutral beam heating power and current drive and limits the achievable βN. Conversely similar plasmas except with qmin just above 1 have approximately classical fast-ion transport. Experiments that take qmin>3 plasmas to higher βP with q95= 11–12 for testing long pulse operation exhibit regimes of better than expected thermal confinement. Compared to the standard high-qmin scenario, the high βP cases have shorter slowing-down time and lower ∇βfast, and this reduces the drive for Alfvénic modes, yielding nearly classical fast-ion transport, high values of normalized confinement, βN, and noninductive current fraction. These results suggest DIII-D might obtain better performance in lower-q95, high-qmin plasmas using broader neutral beam heating profiles and increased direct electron heating power to lower the drive for Alfvén eigenmodes.« less

  2. Fast-ion transport in q min > 2 , high- β steady-state scenarios on DIII-Da)

    NASA Astrophysics Data System (ADS)

    Holcomb, C. T.; Heidbrink, W. W.; Ferron, J. R.; Van Zeeland, M. A.; Garofalo, A. M.; Solomon, W. M.; Gong, X.; Mueller, D.; Grierson, B.; Bass, E. M.; Collins, C.; Park, J. M.; Kim, K.; Luce, T. C.; Turco, F.; Pace, D. C.; Ren, Q.; Podesta, M.

    2015-05-01

    Results from experiments on DIII-D [J. L. Luxon, Fusion Sci. Technol. 48, 828 (2005)] aimed at developing high β steady-state operating scenarios with high- q min confirm that fast-ion transport is a critical issue for advanced tokamak development using neutral beam injection current drive. In DIII-D, greater than 11 MW of neutral beam heating power is applied with the intent of maximizing β N and the noninductive current drive. However, in scenarios with q min > 2 that target the typical range of q 95 = 5-7 used in next-step steady-state reactor models, Alfvén eigenmodes cause greater fast-ion transport than classical models predict. This enhanced transport reduces the absorbed neutral beam heating power and current drive and limits the achievable βN. In contrast, similar plasmas except with q min just above 1 have approximately classical fast-ion transport. Experiments that take q min > 3 plasmas to higher β P with q 95 = 11-12 for testing long pulse operation exhibit regimes of better than expected thermal confinement. Compared to the standard high- q min scenario, the high β P cases have shorter slowing-down time and lower ∇ β fast , and this reduces the drive for Alfvénic modes, yielding nearly classical fast-ion transport, high values of normalized confinement, β N , and noninductive current fraction. These results suggest DIII-D might obtain better performance in lower- q 95 , high- q min plasmas using broader neutral beam heating profiles and increased direct electron heating power to lower the drive for Alfvén eigenmodes.

  3. Fast-ion transport in qmin>2, high- β steady-state scenarios on DIII-D

    SciTech Connect

    Holcomb, C. T.; Heidbrink, W. W.; Ferron, J. R.; Van Zeeland, M. A.; Garofalo, A. M.; Solomon, W. M.; Gong, X.; Mueller, D.; Grierson, B.; Bass, E. M.; Collins, C.; Park, J. M.; Kim, K.; Luce, T. C.; Turco, F.; Pace, D. C.; Ren, Q.; Podesta, M.

    2015-05-22

    The results from experiments on DIII-D [J. L. Luxon, Fusion Sci. Technol. 48, 828 (2005)] aimed at developing high β steady-state operating scenarios with high-qminqmin confirm that fast-ion transport is a critical issue for advanced tokamak development using neutral beam injection current drive. In DIII-D, greater than 11 MW of neutral beam heating power is applied with the intent of maximizing βN and the noninductive current drive. However, in scenarios with qmin>2 that target the typical range of q95= 5–7 used in next-step steady-state reactor models, Alfvén eigenmodes cause greater fast-ion transport than classical models predict. This enhanced transport reduces the absorbed neutral beam heating power and current drive and limits the achievable βN. Conversely similar plasmas except with qmin just above 1 have approximately classical fast-ion transport. Experiments that take qmin>3 plasmas to higher βP with q95= 11–12 for testing long pulse operation exhibit regimes of better than expected thermal confinement. Compared to the standard high-qmin scenario, the high βP cases have shorter slowing-down time and lower ∇βfast, and this reduces the drive for Alfvénic modes, yielding nearly classical fast-ion transport, high values of normalized confinement, βN, and noninductive current fraction. These results suggest DIII-D might obtain better performance in lower-q95, high-qmin plasmas using broader neutral beam heating profiles and increased direct electron heating power to lower the drive for Alfvén eigenmodes.

  4. Magnetic field measurements for study of fast electron transport in magnetized HED plasma

    NASA Astrophysics Data System (ADS)

    Sawada, Hiroshi; Griffin, Brandon; Presura, Radu; Haque, Showera; Sentoku, Yasuhiko

    2014-10-01

    Interaction of megagauss magnetic fields with high energy density (HED) plasma is of great interest in the field of magnetized plasma. The field changes fundamental properties of the HED plasma such as thermal and magnetic diffusion. A coupled capability utilizing the 1.0 MA Zebra pulsed power generator and the 50 TW Leopard laser at Nevada Terawatt Facility enables to create such a condition for studies of magnetized plasma properties. We have conducted an experiment to measure magnetic fields generated by a 1.0 MA, 100 ns Zebra pulsed current in stainless steel coils. Using a 532 nm continuous laser from a single longitudinal mode laser system, the temporal change in the magnetic field was measured with the Faraday rotation in F2 glass. The probe laser passing through the 1.5 mm in radius and 1.75 mm thick glass placed in the vicinity of the inductive coils was split with a Glan-Taylor prism to measure vertical and horizontal polarization components with photodiodes. We will present the analysis of the experimental result and a design of a coupled experiment for study of fast electron transport in the magnetized plasma.

  5. Simulation of laser-plasma interactions and fast-electron transport in inhomogeneous plasma

    SciTech Connect

    Cohen, B.I. Kemp, A.J.; Divol, L.

    2010-06-20

    A new framework is introduced for kinetic simulation of laser-plasma interactions in an inhomogeneous plasma motivated by the goal of performing integrated kinetic simulations of fast-ignition laser fusion. The algorithm addresses the propagation and absorption of an intense electromagnetic wave in an ionized plasma leading to the generation and transport of an energetic electron component. The energetic electrons propagate farther into the plasma to much higher densities where Coulomb collisions become important. The high-density plasma supports an energetic electron current, return currents, self-consistent electric fields associated with maintaining quasi-neutrality, and self-consistent magnetic fields due to the currents. Collisions of the electrons and ions are calculated accurately to track the energetic electrons and model their interactions with the background plasma. Up to a density well above critical density, where the laser electromagnetic field is evanescent, Maxwell's equations are solved with a conventional particle-based, finite-difference scheme. In the higher-density plasma, Maxwell's equations are solved using an Ohm's law neglecting the inertia of the background electrons with the option of omitting the displacement current in Ampere's law. Particle equations of motion with binary collisions are solved for all electrons and ions throughout the system using weighted particles to resolve the density gradient efficiently. The algorithm is analyzed and demonstrated in simulation examples. The simulation scheme introduced here achieves significantly improved efficiencies.

  6. Using the transportable, computer-operated, liquid-scintillator fast-neutron spectrometer system

    SciTech Connect

    Thorngate, J.H.

    1988-11-01

    When a detailed energy spectrum is needed for radiation-protection measurements from approximately 1 MeV up to several tens of MeV, organic-liquid scintillators make good neutron spectrometers. However, such a spectrometer requires a sophisticated electronics system and a computer to reduce the spectrum from the recorded data. Recently, we added a Nuclear Instrument Module (NIM) multichannel analyzer and a lap-top computer to the NIM electronics we have used for several years. The result is a transportable fast-neutron spectrometer system. The computer was programmed to guide the user through setting up the system, calibrating the spectrometer, measuring the spectrum, and reducing the data. Measurements can be made over three energy ranges, 0.6--2 MeV, 1.1--8 MeV, or 1.6--16 MeV, with the spectrum presented in 0.1-MeV increments. Results can be stored on a disk, presented in a table, and shown in graphical form. 5 refs., 51 figs.

  7. Numerical modeling for energy transport and isochoric heating in ultra-fast heated high Z target

    NASA Astrophysics Data System (ADS)

    Mishra, Rohini; Sentoku, Yasuhiko; Hakel, Peter; Mancini, Roberto C.

    2010-11-01

    Collisional Particle-in-Cell (PIC) code is an effective tool to study extreme energy density conditions achieved in intense laser-solid interactions. In the continuous process of developing PIC code, we have recently implemented models to incorporate dynamic ionizations, namely Saha and Thomas Fermi, and radiation cooling (due to Bremsstrahlung and line emissions). We have also revised the existing collision model to take into account bounded electrons in dynamically ionizing target (partially ionized target). One-dimensional PIC simulation of a gold target with new collision model shows strong local heating in a micron distance due to shorter stopping range of fast electrons, which reflects the increased collision frequency due to bound electrons. The peak temperature in the heated region drops significantly due to the radiation cooling to a level of a few hundred eV from keV. We also discuss the target Z dependence on radiation loss and two-dimensional effects such as the resistive magnetic fields in the hot electron transport in metal targets.

  8. Measurements of Fast Ion Transport Due to n = 3 Magnetic Perturbations on DIII-D

    NASA Astrophysics Data System (ADS)

    van Zeeland, M. A.; Evans, T. E.; Ferraro, N. M.; Lanctot, M. J.; Pace, D. C.; Collins, C.; Heidbrink, W. W.; Garcia-Munoz, M.; Hanson, J. M.; Grierson, B. A.; Kramer, G. J.; Nazikian, R.; Allen, S. L.; Lasnier, C. J.; Meyer, W. H.

    2014-10-01

    Measurements of fast ion (FI) transport due to applied n = 3 magnetic perturbations on DIII-D have been made in both ELM suppressed H-mode as well as L-mode discharges. FIDA measurements probe the confined FI profile in the edge and losses to the wall are obtained with scintillator detectors as well as an infrared periscope. In ELM suppressed plasmas FIDA data show a significant depletion of the edge FI profile during application of n = 3 fields. IR imaging of the beam ion prompt loss footprint shows a difference in wall heating depending on phase of the n = 3 perturbation. Measurements of both the impact on the confined FI profile and prompt losses will be compared to full-orbit modeling which predicts up to 10%-15% of the injected beam ions are lost before thermalization. Orbit following simulations also predict an increase in losses due to resonance between the FI drift orbits and the applied n = 3 fields. Measurements during L-mode current ramp plasmas used to scan for signatures of these resonances will be discussed. Work supported in part by the US DOE under DE-FC02-04ER54698, SC-G903402, DE-FG02-04ER54761, DE-AC02-09CH11466, DE-AC52-07NA27344.

  9. Hybrid Simulation of Laser-Plasma Interactions and Fast Electron Transport in Inhomogeneous Plasma

    SciTech Connect

    Cohen, B I; Kemp, A; Divol, L

    2009-05-27

    A new framework is introduced for kinetic simulation of laser-plasma interactions in an inhomogenous plasma motivated by the goal of performing integrated kinetic simulations of fast-ignition laser fusion. The algorithm addresses the propagation and absorption of an intense electromagnetic wave in an ionized plasma leading to the generation and transport of an energetic electron component. The energetic electrons propagate farther into the plasma to much higher densities where Coulomb collisions become important. The high-density plasma supports an energetic electron current, return currents, self-consistent electric fields associated with maintaining quasi-neutrality, and self-consistent magnetic fields due to the currents. Collisions of the electrons and ions are calculated accurately to track the energetic electrons and model their interactions with the background plasma. Up to a density well above critical density, where the laser electromagnetic field is evanescent, Maxwell's equations are solved with a conventional particle-based, finite-difference scheme. In the higher-density plasma, Maxwell's equations are solved using an Ohm's law neglecting the inertia of the background electrons with the option of omitting the displacement current in Ampere's law. Particle equations of motion with binary collisions are solved for all electrons and ions throughout the system using weighted particles to resolve the density gradient efficiently. The algorithm is analyzed and demonstrated in simulation examples. The simulation scheme introduced here achieves significantly improved efficiencies.

  10. Fast electron generation and transport in solid matter irradiated at relativistic intensities. Evidence of vxB acceleration

    NASA Astrophysics Data System (ADS)

    Baton, S. D.; Santos, J. J.; Amiranoff, F.; Popescu, H.; Gremillet, L.; Koenig, M.; Martinolli, E.; Rousseaux, C.; Rabec-Le-Gloahec, M.; Hall, T. A.; Batani, D.; Perelli, E.; Scianitti, F.; Cowan, T. E.

    2002-11-01

    In the context of the fast electron transport in solid matter and the fast ignitor scheme,we report on measurements of second harmonic of the laser light observed on the rear side of solid targets irradiated by the 100 TW laser at LULI. This emission can be explained by the acceleration of short bunches of electrons in the front of the target by the vxB force. The observations indicate that, in our conditions, the minimum fraction of the laser energy transferred to these electron bunches is of the order of 1 °.

  11. Collective Thomson scattering measurements of fast-ion transport due to sawtooth crashes in ASDEX Upgrade

    NASA Astrophysics Data System (ADS)

    Rasmussen, J.; Nielsen, S. K.; Stejner, M.; Galdon-Quiroga, J.; Garcia-Munoz, M.; Geiger, B.; Jacobsen, A. S.; Jaulmes, F.; Korsholm, S. B.; Lazanyi, N.; Leipold, F.; Ryter, F.; Salewski, M.; Schubert, M.; Stober, J.; Wagner, D.; the ASDEX Upgrade Team; the EUROFusion MST1 Team

    2016-11-01

    Sawtooth instabilities can modify heating and current-drive profiles and potentially increase fast-ion losses. Understanding how sawteeth redistribute fast ions as a function of sawtooth parameters and of fast-ion energy and pitch is hence a subject of particular interest for future fusion devices. Here we present the first collective Thomson scattering (CTS) measurements of sawtooth-induced redistribution of fast ions at ASDEX Upgrade. These also represent the first localized fast-ion measurements on the high-field side of this device. The results indicate fast-ion losses in the phase-space measurement volume of about 50% across sawtooth crashes, in good agreement with values predicted with the Kadomtsev sawtooth model implemented in TRANSP and with the sawtooth model in the EBdyna_go code. In contrast to the case of sawteeth, we observe no fast-ion redistribution in the presence of fishbone modes. We highlight how CTS measurements can discriminate between different sawtooth models, in particular when aided by multi-diagnostic velocity-space tomography, and briefly discuss our results in light of existing measurements from other fast-ion diagnostics.

  12. Bayesian meta-analysis of the effect of fasting, transport and lairage times on four attributes of pork meat quality.

    PubMed

    Salmi, B; Trefan, L; Bünger, L; Doeschl-Wilson, A; Bidanel, J P; Terlouw, C; Larzul, C

    2012-03-01

    Technological meat quality is a significant economic factor in pork production, and numerous publications have shown that it is strongly influenced both by genetic status and by rearing and slaughter conditions. The quality of meat is often described by meat pH at different times postmortem, as well as by color and drip loss. A meta-analysis based on a database built from 27 studies corresponding to a total of 6526 animals classified was carried out. The purpose of this meta-analysis was to study the effect of fasting, lairage and transport durations on four main attributes of the technological pork meat quality. A Bayesian hierarchical meta-regression approach was adopted. The results of our meta-analysis showed that fasting time had a significant effect on pH measured 24h post-mortem (pHu) and drip loss (DL) measured in longissimus muscle. While, lairage affected only the pHu in semimembranosus muscle. Interestingly, we found that DL was the lone attribute that was affected by transport time and its interaction with fasting time.

  13. Experimental Study on Fast Electrons Transport in Ultra-intense Laser Irradiated Solid Targets by Transition Radiation

    NASA Astrophysics Data System (ADS)

    Zhijian, Zheng; Guangcan, Wang; Yuqiu, Gu

    2008-11-01

    The experiment was performed with SILEX laser facility(Ti-saphhire) at LFRC in China. The SILEX parameter: wavelength 0.8μm, duration 35fs, output power 280TW, contrast 5*105, The focal spot φ10μm(F/1.7), intensity on target surface 1*10^19W/cm^2(F/3). The main diagnostic equipments are the electron spectrometer, OMA spectrometer, optical streak camera. Some experimental results are given: The spectrum of optical emission from rear surface is rather narrow around some particular frequencies(1φ, 2φ, 3φ), We ascribe and confirm that the spike-like spectral line that is coherent transition radiation; The coherent light is also seen on time-integrated image with ring-patter due to Weibel instability of the fast electron transport; Obtained experimental cure of target thickness vs OTR image intensity is relative to mean free path of fast electron; The measuring optical transition radiation(OTR) duration of 171ps much longer than 1ps duration of fast electron transport target, the possible explanation is that the OTR duration to be determined magnetic diffusion time.

  14. Effects of age on calcium transport activity of sarcoplasmic reticulum in fast- and slow-twitch rat muscle fibres.

    PubMed Central

    Larsson, L; Salviati, G

    1989-01-01

    1. The calcium transport activity of the sarcoplasmic reticulum (SR) was measured in chemically skinned single fast- and slow-twitch muscle fibres from young (3 months) and old (23-24 months) rats. Contractile properties, the myosin heavy chain (MHC) composition and enzyme histochemical features were studied in relation to the SR characteristics. 2. In fast-twitch single motor units, the contraction time of the isometric twitch increased (P less than 0.001) from 13 +/- 1 ms in young animals to 18 +/- 2 ms in old ones. In the slow-twitch soleus, the contraction (P less than 0.001) and half-relaxation (P less than 0.05) times increased from 30 +/- 5 and 45 +/- 10 ms, respectively, in the young animals to 43 +/- 3 and 55 +/- 4 ms in the old ones. The proportion of slow-twitch (type I) fibres increased (P less than 0.05) with age in the soleus from 92 +/- 6 to 98 +/- 2% and the proportion of fast-twitch fibres (type IIA) decreased (P less than 0.01) from 6 +/- 5 to 0 +/- 0%. 3. The Ca2+ accumulation capacity (an index of SR volume), the rate of Ca2+ uptake and the fractional rate of SR filling (an estimate of the specific activity of the Ca2+ pump) were decreased by 18 (P less than 0.05), 32 (P less than 0.01) and 32% (P less than 0.001), respectively, in the old fast-twitch muscle fibres. In the slow-twitch muscle fibres, on the other hand, no significant age-related changes were observed in the Ca2+ transport activity of the SR. Thus, ageing exerts a differential influence on SR volume and function in fast- and slow-twitch fibres. 4. It is concluded that an age-related impairment of intrinsic SR function and a decrease in SR volume are probable factors underlying the decreased speed of contraction of fast-twitch muscle fibres in old age. In the slow-twitch soleus, on the other hand, one or more other mechanisms are responsible for the age-related decrease in the speed of contraction. The loss of fast-twitch muscle fibres in old soleus is one mechanism, but not the

  15. Communication: fast transport and relaxation of vibrational energy in polymer chains.

    PubMed

    Kurnosov, Arkady A; Rubtsov, Igor V; Burin, Alexander L

    2015-01-01

    We investigate ballistic vibrational energy transport through optical phonon band in oligomeric chains in the presence of decoherence. An exact solution is obtained for the excitation density in the space-time representation in the continuous limit and this solution is used to characterize the energy transport time and intensity. Three transport mechanisms are identified such as ballistic, diffusive, and directed diffusive regimes, occurring at different distances and time scales. The crossover between the two diffusive regimes is continuous, while the switch between the ballistic and diffusive mechanisms occurs in a discontinuous manner in accord with the recent experimental results on energy transport in perfluoroalkanes. PMID:25573545

  16. Effects of colchicine on the intestinal transport of endogenous lipid. Ultrastructural, biochemical, and radiochemical studies in fasting rats

    SciTech Connect

    Pavelka, M.; Gangl, A.

    1983-03-01

    The involvement of microtubules in the transepithelial transport of exogenous lipid in intestinal absorptive cells has been suggested. Using electronmicroscopic, biochemical, and radiochemical methods, researchers have studied the effects of the antimicrotubular agent colchicine on the intestinal mucosa and on the intestinal transport of endogenous lipid of rats in the fasting state. After colchicine treatment, the concentration of triglycerides in intestinal mucosa of rats fasted for 24 h doubled, and electron microscopic studies showed a striking accumulation of lipid particles in absorptive epithelial cells of the tips of jejunal villi. These findings suggest that colchicine interferes with the intestinal transepithelial transport of endogenous lipoproteins. Additional studies, using an intraduodenal pulse injection of (/sup 14/C)linoleic acid, showed that colchicine does not affect the uptake of fatty acids by intestinal mucosa. However, it had divergent effects on fatty acid esterification, enhancing their incorporation into triglycerides relative to phospholipids, and caused a significant accumulation of endogenous diglycerides, triglycerides, and cholesterol esters within the absorptive intestinal epithelium. Detailed ultrastructural and morphometric studies revealed a decrease of visible microtubules, and a displacement of the smooth and rough endoplasmic reticulum and Golgi apparatus. Furthermore, it is shown that after colchicine treatment, microvilli appear at the lateral plasma membrane of intestinal absorptive cells, a change not previously reported to our knowledge. Thus, our study shows that colchicine causes significant changes in enterocyte ultrastructure and colchicine perturbs the reesterification of absorbed endogenous fatty acids and their secretion in the form of triglyceride-rich lipoproteins from the enterocyte.

  17. Parametric Dependence Of Fast-ion Transport Events On The National Spherical Torus Experiment

    SciTech Connect

    Fredrickson, Erik; Gorelenkov, N. N.; Podesta, M.; Gerhardt, S. P.; Bell, R. E.; Diallo, A.; LeBlanc, B.; Bortolon, A.

    2014-03-31

    Neutral-beam heated tokamak plasmas commonly have more than one third of the plasma kinetic energy in the non-thermal energetic beam ion population. This population of fast ions heats the plasma, provides some of the current drive, and can affect the stability (positively or negatively) of magnetohydrodynamic instabilities. This population of energetic ions is not in thermodynamic equilibrium, thus there is free-energy available to drive instabilities, which may lead to redistribution of the fast ion population. Understanding under what conditions beam-driven instabilities arise, and the extent of the resulting perturbation to the fast ion population, is important for predicting and eventually demonstrating non-inductive current ramp-up and sustainment in NSTX-U, as well as the performance of future fusion plasma experiments such as ITER. This paper presents an empirical approach towards characterizing the stability boundaries for some common energetic-ion-driven instabilities seen on NSTX.

  18. Recent experiment on fast electron transport in ultra-high intensity laser interaction

    NASA Astrophysics Data System (ADS)

    Batani, D.; Baton, S.; Koenig, M.; Guillou, P.; Loupias, B.; Vinci, T.; Rousseaux, C.; Gremillet, L.; Morace, A.; Redaelli, R.; Nakatsutsumi, M.; Kodama, R.; Ozaki, N.; Norimatsu, T.; Rassuchine, J.; Cowan, T.; Dorchies, F.; Fourment, C.; Santos, J. J.

    2008-05-01

    We performed an experiment with cone targets in planar geometry devoted to the study of fast electron generation, propagation, and target heating. This was done at LULI with the 100 TW laser at intensities up to 1019 W/cm2. Fast electrons penetration, with and without cones, was studied with different diagnostics (Kα imaging, Kα spectroscopy, visible emission) for ω or 2ω irradiation. At ω, the pre-plasma generated by the laser pedestal fills the cone and prevents the beam from reaching the tip.

  19. Measurements and modeling of Alfven eigenmode induced fast ion transport and loss in DIII-D and ASDEX Upgrade

    SciTech Connect

    Van Zeeland, M. A.; Fisher, R. K.; Hyatt, A. W.; Heidbrink, W. W.; Pace, D. C.; Muscatello, C. M.; Zhu, Y. B.; Garcia Munoz, M.; Geiger, B.; Maraschek, M.; Suttrop, W.; Tardini, G.; Kramer, G. J.; White, R. B.; Gorelenkova, M.; Gorelenkov, N. N.; Nazikian, R.; Aekaeslompolo, S.; Austin, M. E.; Boom, J. E.

    2011-05-15

    Neutral beam injection into reversed magnetic shear DIII-D and ASDEX Upgrade plasmas produces a variety of Alfvenic activity including toroidicity-induced Alfven eigenmodes and reversed shear Alfven eigenmodes (RSAEs). These modes are studied during the discharge current ramp phase when incomplete current penetration results in a high central safety factor and increased drive due to multiple higher order resonances. Scans of injected 80 keV neutral beam power on DIII-D showed a transition from classical to AE dominated fast ion transport and, as previously found, discharges with strong AE activity exhibit a deficit in neutron emission relative to classical predictions. By keeping beam power constant and delaying injection during the current ramp, AE activity was reduced or eliminated and a significant improvement in fast ion confinement observed. Similarly, experiments in ASDEX Upgrade using early 60 keV neutral beam injection drove multiple unstable RSAEs. Periods of strong RSAE activity are accompanied by a large (peak {delta}S{sub n}/S{sub n{approx_equal}}60%) neutron deficit. Losses of beam ions modulated at AE frequencies were observed using large bandwidth energy and pitch resolving fast ion loss scintillator detectors and clearly identify their role in the process. Modeling of DIII-D loss measurements using guiding center following codes to track particles in the presence of ideal magnetohydrodynamic (MHD) calculated AE structures (validated by comparison to experiment) is able to reproduce the dominant energy, pitch, and temporal evolution of these losses. While loss of both co and counter current fast ions occurs, simulations show that the dominant loss mechanism observed is the mode induced transition of counter-passing fast ions to lost trapped orbits. Modeling also reproduces a coherent signature of AE induced losses and it was found that these coherent losses scale proportionally with the amplitude; an additional incoherent contribution scales

  20. Fast ion transport during applied 3D magnetic perturbations on DIII-D

    NASA Astrophysics Data System (ADS)

    Van Zeeland, M. A.; Ferraro, N. M.; Grierson, B. A.; Heidbrink, W. W.; Kramer, G. J.; Lasnier, C. J.; Pace, D. C.; Allen, S. L.; Chen, X.; Evans, T. E.; García-Muñoz, M.; Hanson, J. M.; Lanctot, M. J.; Lao, L. L.; Meyer, W. H.; Moyer, R. A.; Nazikian, R.; Orlov, D. M.; Paz-Soldan, C.; Wingen, A.

    2015-07-01

    Measurements show fast ion losses correlated with applied three-dimensional (3D) fields in a variety of plasmas ranging from L-mode to resonant magnetic perturbation (RMP) edge localized mode (ELM) suppressed H-mode discharges. In DIII-D L-mode discharges with a slowly rotating n=2 magnetic perturbation, scintillator detector loss signals synchronized with the applied fields are observed to decay within one poloidal transit time after beam turn-off indicating they arise predominantly from prompt loss orbits. Full orbit following using M3D-C1 calculations of the perturbed fields and kinetic profiles reproduce many features of the measured losses and points to the importance of the applied 3D field phase with respect to the beam injection location in determining the overall impact on prompt beam ion loss. Modeling of these results includes a self-consistent calculation of the 3D perturbed beam ion birth profiles and scrape-off-layer ionization, a factor found to be essential to reproducing the experimental measurements. Extension of the simulations to full slowing down timescales, including fueling and the effects of drag and pitch angle scattering, show the applied n=3 RMPs in ELM suppressed H-mode plasmas can induce a significant loss of energetic particles from the core. With the applied n=3 fields, up to 8.4% of the injected beam power is predicted to be lost, compared to 2.7% with axisymmetric fields only. These fast ions, originating from minor radii ρ >0.7 , are predicted to be primarily passing particles lost to the divertor region, consistent with wide field-of-view infrared periscope measurements of wall heating in n=3 RMP ELM suppressed plasmas. Edge fast ion {{\\text{D}}α} (FIDA) measurements also confirm a large change in edge fast ion profile due to the n=3 fields, where the effect was isolated by using short 50 ms RMP-off periods during which ELM suppression was maintained yet the fast ion profile was allowed to recover. The role of resonances

  1. Synergy between fast-ion transport by core MHD and test blanket module fields in DIII-D experiments

    SciTech Connect

    Heidbrink, W. W.; Austin, M. E.; Collins, C. S.; Gray, T.; Grierson, B. A.; Kramer, G. J.; Lanctot, M.; Pace, D. C.; Van Zeeland, M. A.; Mclean, A. G.

    2015-07-21

    We measured fast-ion transport caused by the combination of MHD and a mock-up test-blanket module (TBM) coil in the DIII-D tokamak. The primary diagnostic is an infrared camera that measures the heat flux on the tiles surrounding the coil. The combined effects of the TBM and four other potential sources of transport are studied: neoclassical tearing modes, Alfvén eigenmodes, sawteeth, and applied resonant magnetic perturbation fields for the control of edge localized modes. A definitive synergistic effect is observed at sawtooth crashes where, in the presence of the TBM, the localized heat flux at a burst increases from 0.36±0.27 to 2.6±0.5 MW/m-2.

  2. Synergy between fast-ion transport by core MHD and test blanket module fields in DIII-D experiments

    DOE PAGESBeta

    Heidbrink, W. W.; Austin, M. E.; Collins, C. S.; Gray, T.; Grierson, B. A.; Kramer, G. J.; Lanctot, M.; Pace, D. C.; Van Zeeland, M. A.; Mclean, A. G.

    2015-07-21

    We measured fast-ion transport caused by the combination of MHD and a mock-up test-blanket module (TBM) coil in the DIII-D tokamak. The primary diagnostic is an infrared camera that measures the heat flux on the tiles surrounding the coil. The combined effects of the TBM and four other potential sources of transport are studied: neoclassical tearing modes, Alfvén eigenmodes, sawteeth, and applied resonant magnetic perturbation fields for the control of edge localized modes. A definitive synergistic effect is observed at sawtooth crashes where, in the presence of the TBM, the localized heat flux at a burst increases from 0.36±0.27 tomore » 2.6±0.5 MW/m-2.« less

  3. Design and fabrication of hollow-core photonic crystal fibers for high power fast laser beam transportation and pulse compression

    NASA Astrophysics Data System (ADS)

    Wang, Y. Y.; Peng, Xiang; Alharbi, M.; Dutin, C. F.; Bradley, T. D.; Mielke, Michael; Booth, Timothy; Benabid, F.

    2012-03-01

    We report on recent design and fabrication of Kagome type hollow-core photonic crystal fiber (HC-PCF) for the purpose of high power fast laser beam transportation. The fabricated seven-cell three-ring hypocycloid-shaped large core fiber exhibits an up-to-date lowest attenuation (among all Kagome fibers) of 40dB/km over a broadband transmission centered at 1500nm. We show that the large core size, low attenuation, broadband transmission, single modedness, low dispersion and relatively low banding loss makes it an ideal host for high power laser beam transportation. By filling the fiber with helium gas, a 74μJ, 850fs and 40kHz repetition rate ultra-short pulse at 1550nm has been faithfully delivered with little propagation pulse distortion. Compression of a 105μJ laser pulse from 850fs to 300fs has been achieved by operating the fiber in ambient air.

  4. Synergy between fast-ion transport by core MHD and test blanket module fields in DIII-D experiments

    NASA Astrophysics Data System (ADS)

    Heidbrink, W. W.; Austin, M. E.; Collins, C. S.; Gray, T.; Grierson, B. A.; Kramer, G. J.; Lanctot, M.; Pace, D. C.; Van Zeeland, M. A.; Mclean, A. G.

    2015-08-01

    Fast-ion transport caused by the combination of MHD and a mock-up test-blanket module (TBM) coil is measured in the DIII-D tokamak. The primary diagnostic is an infrared camera that measures the heat flux on the tiles surrounding the coil. The combined effects of the TBM and four other potential sources of transport are studied: neoclassical tearing modes, Alfén eigenmodes, sawteeth, and applied resonant magnetic perturbation fields for the control of edge localized modes. A definitive synergistic effect is observed at sawtooth crashes where, in the presence of the TBM, the localized heat flux at a burst increases from 0.36+/- 0.27 to 2.6+/- 0.5 MW m-2.

  5. Life cycle assessment of the production of hydrogen and transportation fuels from corn stover via fast pyrolysis

    NASA Astrophysics Data System (ADS)

    Zhang, Yanan; Hu, Guiping; Brown, Robert C.

    2013-06-01

    This life cycle assessment evaluates and quantifies the environmental impacts of the production of hydrogen and transportation fuels from the fast pyrolysis and upgrading of corn stover. Input data for this analysis come from Aspen Plus modeling, a GREET (Greenhouse Gases, Regulated Emissions, and Energy Use in Transportation) model database and a US Life Cycle Inventory Database. SimaPro 7.3 software is employed to estimate the environmental impacts. The results indicate that the net fossil energy input is 0.25 MJ and 0.23 MJ per km traveled for a light-duty vehicle fueled by gasoline and diesel fuel, respectively. Bio-oil production requires the largest fossil energy input. The net global warming potential (GWP) is 0.037 kg CO2eq and 0.015 kg CO2eq per km traveled for a vehicle fueled by gasoline and diesel fuel, respectively. Vehicle operations contribute up to 33% of the total positive GWP, which is the largest greenhouse gas footprint of all the unit processes. The net GWPs in this study are 88% and 94% lower than for petroleum-based gasoline and diesel fuel (2005 baseline), respectively. Biomass transportation has the largest impact on ozone depletion among all of the unit processes. Sensitivity analysis shows that fuel economy, transportation fuel yield, bio-oil yield, and electricity consumption are the key factors that influence greenhouse gas emissions.

  6. Boundary-artifact-free phase retrieval with the transport of intensity equation: fast solution with use of discrete cosine transform.

    PubMed

    Zuo, Chao; Chen, Qian; Asundi, Anand

    2014-04-21

    The transport of intensity equation (TIE) is a two-dimensional second order elliptic partial differential equation that must be solved under appropriate boundary conditions. However, the boundary conditions are difficult to obtain in practice. The fast Fourier transform (FFT) based TIE solutions are widely adopted for its speed and simplicity. However, it implies periodic boundary conditions, which lead to significant boundary artifacts when the imposed assumption is violated. In this work, TIE phase retrieval is considered as an inhomogeneous Neumann boundary value problem with the boundary values experimentally measurable around a hard-edged aperture, without any assumption or prior knowledge about the test object and the setup. The analytic integral solution via Green's function is given, as well as a fast numerical implementation for a rectangular region using the discrete cosine transform. This approach is applicable for the case of non-uniform intensity distribution with no extra effort to extract the boundary values from the intensity derivative signals. Its efficiency and robustness have been verified by several numerical simulations even when the objects are complex and the intensity measurements are noisy. This method promises to be an effective fast TIE solver for quantitative phase imaging applications. PMID:24787811

  7. Guidelines for Transportation, Handling, and Use of Fast Pyrolysis Bio-Oil. Part 1. Flammability and Toxicity

    SciTech Connect

    Oasmaa, Anja; Kalli, Anssi; Lindfors, Christian; Elliott, Douglas C.; Springer, David L.; Peacocke, Cordner; Chiaramonti, David

    2012-05-04

    An alternative sustainable fuel, biomass-derived fast pyrolysis oil or 'bio-oil', is coming into the market. Fast pyrolysis pilot and demonstration plants for fuel applications producing tonnes of bio-oil are in operation, and commercial plants are under design. There will be increasingly larger amounts of bio-oil transportation on water and by land, leading to a need for specifications and supporting documentation. Bio-oil is different from conventional liquid fuels, and therefore must overcome both technical and marketing hurdles for its acceptability in the fuels market. A comprehensive Material Safety Data Sheet (MSDS) is required, backed with independent testing and certification. In order to standardise bio-oil quality specifications are needed. The first bio-oil burner fuel standard in ASTM (D7544) was approved in 2009. CEN standardisation has been initiated in Europe. In the EU a new chemical regulation system, REACH (Registration, Evaluation and Authorisation of Chemicals) is being applied. Registration under REACH has to be made if bio-oil is produced or imported to the EU. In the USA and Canada, bio-oil has to be filed under TOSCA (US Toxic Substances Control Act). In this paper the state of the art on standardisation is discussed, and new data for the transportation guidelines is presented. The focus is on flammability and toxicity.

  8. A CFD-based wind solver for a fast response transport and dispersion model

    SciTech Connect

    Gowardhan, Akshay A; Brown, Michael J; Pardyjak, Eric R; Senocak, Inanc

    2010-01-01

    In many cities, ambient air quality is deteriorating leading to concerns about the health of city inhabitants. In urban areas with narrow streets surrounded by clusters of tall buildings, called street canyons, air pollution from traffic emissions and other sources is difficult to disperse and may accumulate resulting in high pollutant concentrations. For various situations, including the evacuation of populated areas in the event of an accidental or deliberate release of chemical, biological and radiological agents, it is important that models should be developed that produce urban flow fields quickly. For these reasons it has become important to predict the flow field in urban street canyons. Various computational techniques have been used to calculate these flow fields, but these techniques are often computationally intensive. Most fast response models currently in use are at a disadvantage in these cases as they are unable to correlate highly heterogeneous urban structures with the diagnostic parameterizations on which they are based. In this paper, a fast and reasonably accurate computational fluid dynamics (CFD) technique that solves the Navier-Stokes equations for complex urban areas has been developed called QUIC-CFD (Q-CFD). This technique represents an intermediate balance between fast (on the order of minutes for a several block problem) and reasonably accurate solutions. The paper details the solution procedure and validates this model for various simple and complex urban geometries.

  9. Microwave-assisted fast vapor-phase transport synthesis of MnAPO-5 molecular sieves

    SciTech Connect

    Shao Hui; Yao Jianfeng; Ke Xuebin; Zhang Lixiong Xu Nanping

    2009-04-02

    MnAPO-5 was prepared by a microwave-assisted vapor-phase transport method at 180 deg. C in short times. The products were characterized by X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectra, UV-vis spectroscopic measurement, NH{sub 3}-temperature-programmed desorption and esterification reaction. It was found that dry gels prepared with aluminum isopropoxide, phosphoric acid and manganese acetate could be transferred to MnAPO-5 in the vapors of triethylamine and water by the microwave-assisted vapor-phase transport method at 180 deg. C for less than 30 min. The crystallization time was greatly reduced by the microwave heating compared with the conventional heating. The resulting MnAPO-5 exhibited much smaller particle sizes, higher surface areas and slightly higher catalytic activity in the esterification of acetic acid and butyl alcohol than those prepared by the conventional vapor-phase transport method and hydrothermal synthesis.

  10. TIME-DEPENDENT PERPENDICULAR TRANSPORT OF FAST CHARGED PARTICLES IN A TURBULENT MAGNETIC FIELD

    SciTech Connect

    Fraschetti, F.; Jokipii, J. R.

    2011-06-20

    We present an analytic derivation of the temporal dependence of the perpendicular transport coefficient of charged particles in magnetostatic turbulence, for times smaller than the time needed for charged particles to travel the turbulence correlation length. This time window is left unexplored in most transport models. In our analysis all magnetic scales are taken to be much larger than the particle gyroradius, so that perpendicular transport is assumed to be dominated by the guiding center motion. Particle drift from the local magnetic field lines (MFLs) and magnetic field line random walk are evaluated separately for slab and three-dimensional (3D) isotropic turbulence. Contributions of wavelength scales shorter and longer than the turbulence coherence length are compared. In contrast to the slab case, particles in 3D isotropic turbulence unexpectedly diffuse from local MFLs; this result questions the common assumption that particle magnetization is independent of turbulence geometry. Extensions of this model will allow for a study of solar wind anisotropies.

  11. Pharmacokinetic Model of the Transport of Fast-Acting Insulin From the Subcutaneous and Intradermal Spaces to Blood.

    PubMed

    Lv, Dayu; Kulkarni, Sandip D; Chan, Alice; Keith, Stephen; Pettis, Ron; Kovatchev, Boris P; Farhi, Leon S; Breton, Marc D

    2015-07-01

    Pharmacokinetic (PK) models describing the transport of insulin from the injection site to blood assist clinical decision making and are part of in silico platforms for developing and testing of insulin delivery strategies for treatment of patients with diabetes. The ability of these models to accurately describe all facets of the in vivo insulin transport is therefore critical for their application. Here, we propose a new model of fast-acting insulin analogs transport from the subcutaneous and intradermal spaces to blood that can accommodate clinically observed biphasic appearance and delayed clearance of injected insulin, 2 phenomena that are not captured by existing PK models. To develop the model we compare 9 insulin transport PK models which describe hypothetical insulin delivery pathways potentially capable of approximating biphasic appearance of exogenous insulin. The models are tested with respect to their ability to describe clinical data from 10 healthy volunteers which received 1 subcutaneous and 2 intradermal insulin injections on 3 different occasions. The optimal model, selected based on information and posterior identifiability criteria, assumes that insulin is delivered at the administrative site and is then transported to the bloodstream via 2 independent routes (1) diffusion-like process to the blood and (2) combination of diffusion-like processes followed by an additional compartment before entering the blood. This optimal model accounts for biphasic appearance and delayed clearance of exogenous insulin. It agrees better with the clinical data as compared to commonly used models and is expected to improve the in silico development and testing of insulin treatment strategies, including artificial pancreas systems. PMID:25759184

  12. Bioinspired tilt-angle fabricated structure gradient fibers: micro-drops fast transport in a long-distance

    NASA Astrophysics Data System (ADS)

    Chen, Yuan; Wang, Lin; Xue, Yan; Jiang, Lei; Zheng, Yongmei

    2013-10-01

    Issues of surfaces, e.g., inspired from beetle's back, spider silk, cactus stem, etc., become the active area of research on designing novel materials in need of human beings to acquire fresh water resource from air. However, the design of materials on surface structure is little achieved on controlling of micro-scale drop transport in a long distance. Here, we report the ability of micro-drop transport in a long distance on a bioinspired Fibers with Gradient Spindle-knots (BFGS), which are fabricated by tilt angle dip-coating method. The micro-drop of ~0.25 μL transports in distance of ~5.00 mm, with velocity of 0.10-0.22 m s-1 on BFGS. It is attributed to the multi-level cooperation of the release energy of drop coalescence along the gradient spindle-knots, in addition to capillary adhesion force and continuous difference of Laplace pressure, accordingly, water drops are driven to move fast directionally in a long distance on BFGS.

  13. Development of a New and Fast Linear Solver for Multi-component Reactive Transport Simulation

    NASA Astrophysics Data System (ADS)

    Qiao, C.; Li, L.; Bao, C.; Hu, X.; Johns, R.; Xu, J.

    2013-12-01

    Reactive transport models (RTM) have been extensively used to understand the coupling between solute transport and (bio) geochemical reactions in complex earth systems. RTM typically involves a large number of primary and secondary species with a complex reaction network in large domains. The computational expenses increase significantly with the number of grid blocks and the number of chemical species. Within both the operator splitting approach (OS) and the global implicit approach (GI) that are commonly used, the steps that involve Newton-Raphson method are typically one of the most time-consuming parts (up to 80% to 90% of CPU times). Under such circumstances, accelerating reactive transport simulation is very essential. In this research, we present a physics-based linear system solution strategy for general reactive transport models with many species. We observed up to five times speed up for the linear solver portion of the simulations in our test cases. Our new linear solver takes advantage of the sparsity of the Jacobian matrix arising from the reaction network. The Jacobian matrix for the speciation problem is typically considered as a dense matrix and solved with a direct method such as Gaussian elimination. For the reactive transport problem, the graph of the local Jacobian matrix has a one-to-one correspondence to the reaction network graph. The Jacobian matrix is commonly sparse and has the same sparsity structure for the same reaction network. We developed a strategy that performs a minimum degree of reordering and symbolic factorization to determine the non-zero pattern at the beginning of the OS and GI simulation. During the speciation calculation in OS, we calculate the L and U factors and solve the triangular matrices according to the non-zero pattern. For GI, our strategy can be applied to inverse the diagonal blocks in the block-Jacobi preconditioner and smoothers of the multigrid preconditioners in iterative solvers. Our strategy is naturally

  14. Fast Na/+/-ion transport in skeleton structures. [solid electrolyte applications

    NASA Technical Reports Server (NTRS)

    Goodenough, J. B.; Hong, H. Y.-P.; Kafalas, J. A.

    1976-01-01

    The skeleton structures considered in the investigations consist of a rigid subarray with an interconnected interstitial space in which ions move in three dimensions. The classes of skeleton structures investigated include the Im3 phase of high-pressure KSbO3, the defect-pyrochlore structure illustrated by RbMgAlF6, and the carnegieite structure of high-temperature NaAlSiO4. A description is given of the results obtained in transport measurements involving dense polycrystalline ceramic disks. Results obtained in the case of the Na(+)-ion transport in Na3Zr2PSi2O12 appear particularly promising concerning the possible use of such substances in solid-electrolyte applications.

  15. On the Upscaling of Reaction-Transport Processes in Porous Media with Fast Kinetics

    SciTech Connect

    Kechagi, P.; Tsimpanogiannis, I.; Yortsos, Y.C.; Lichtner, P.

    2001-01-09

    This report is organized as follows: Provide a brief review of the upscaling constraints of the type (2) for a typical diffusion-reaction system. In this an analogy with two-phase flow in porous media was drawn. Then, using the methodology of QW a problem at the unit cell for the computation of the effective mass transfer coefficient, in processes where local thermodynamic equilibrium applies was derived. This problem is found to be different than in QW, as it depends on the gradients of the macroscale variable, and can be cast in terms of an eigenvalue problem. Two simple, examples, one involving advection-dissolution and another involving drying in a pore network, was presented to illustrate the coupling between scales and to show the quantitative effect in case this coupling was neglected. Finally, similar ideas and an illustrative example was applied to reaction-diffusion systems with fast kinetics, where an equilibrium state is approached.

  16. Direct observation of ultrafast surface transport of laser-driven fast electrons in a solid target

    SciTech Connect

    Singh, Prashant Kumar; Chatterjee, Gourab; Adak, Amitava; Ahmed, Saima; Lad, Amit D.; Ravindra Kumar, G.; Cui, Y. Q.; Wang, W. M.; Sheng, Z. M.

    2013-11-15

    We demonstrate rapid spread of surface ionization on a glass target excited by an intense, ultrashort laser pulse at an intensity of 3 × 10{sup 17} W cm{sup −2}. Time- and space-resolved reflectivity of the target surface indicates that the initial plasma region created by the pump pulse expands at c/7. The measured quasi-static megagauss magnetic field is found to expand in a manner very similar to that of surface ionization. Two-dimensional particle-in-cell simulations reproduce measurements of surface ionization and magnetic fields. Both the experiment and simulation convincingly demonstrate the role of self-induced electric and magnetic fields in confining fast electrons along the target-vacuum interface.

  17. Quantitative measurements and modeling of cargo-motor interactions during fast transport in the living axon

    NASA Astrophysics Data System (ADS)

    Seamster, Pamela E.; Loewenberg, Michael; Pascal, Jennifer; Chauviere, Arnaud; Gonzales, Aaron; Cristini, Vittorio; Bearer, Elaine L.

    2012-10-01

    The kinesins have long been known to drive microtubule-based transport of sub-cellular components, yet the mechanisms of their attachment to cargo remain a mystery. Several different cargo-receptors have been proposed based on their in vitro binding affinities to kinesin-1. Only two of these—phosphatidyl inositol, a negatively charged lipid, and the carboxyl terminus of the amyloid precursor protein (APP-C), a trans-membrane protein—have been reported to mediate motility in living systems. A major question is how these many different cargo, receptors and motors interact to produce the complex choreography of vesicular transport within living cells. Here we describe an experimental assay that identifies cargo-motor receptors by their ability to recruit active motors and drive transport of exogenous cargo towards the synapse in living axons. Cargo is engineered by derivatizing the surface of polystyrene fluorescent nanospheres (100 nm diameter) with charged residues or with synthetic peptides derived from candidate motor receptor proteins, all designed to display a terminal COOH group. After injection into the squid giant axon, particle movements are imaged by laser-scanning confocal time-lapse microscopy. In this report we compare the motility of negatively charged beads with APP-C beads in the presence of glycine-conjugated non-motile beads using new strategies to measure bead movements. The ensuing quantitative analysis of time-lapse digital sequences reveals detailed information about bead movements: instantaneous and maximum velocities, run lengths, pause frequencies and pause durations. These measurements provide parameters for a mathematical model that predicts the spatiotemporal evolution of distribution of the two different types of bead cargo in the axon. The results reveal that negatively charged beads differ from APP-C beads in velocity and dispersion, and predict that at long time points APP-C will achieve greater progress towards the presynaptic

  18. Quantitative measurements and modeling of cargo–motor interactions during fast transport in the living axon

    PubMed Central

    Seamster, Pamela E; Loewenberg, Michael; Pascal, Jennifer; Chauviere, Arnaud; Gonzales, Aaron; Cristini, Vittorio; Bearer, Elaine L

    2013-01-01

    The kinesins have long been known to drive microtubule-based transport of sub-cellular components, yet the mechanisms of their attachment to cargo remain a mystery. Several different cargo-receptors have been proposed based on their in vitro binding affinities to kinesin-1. Only two of these—phosphatidyl inositol, a negatively charged lipid, and the carboxyl terminus of the amyloid precursor protein (APP-C), a trans-membrane protein—have been reported to mediate motility in living systems. A major question is how these many different cargo, receptors and motors interact to produce the complex choreography of vesicular transport within living cells. Here we describe an experimental assay that identifies cargo–motor receptors by their ability to recruit active motors and drive transport of exogenous cargo towards the synapse in living axons. Cargo is engineered by derivatizing the surface of polystyrene fluorescent nanospheres (100 nm diameter) with charged residues or with synthetic peptides derived from candidate motor receptor proteins, all designed to display a terminal COOH group. After injection into the squid giant axon, particle movements are imaged by laser-scanning confocal time-lapse microscopy. In this report we compare the motility of negatively charged beads with APP-C beads in the presence of glycine-conjugated non-motile beads using new strategies to measure bead movements. The ensuing quantitative analysis of time-lapse digital sequences reveals detailed information about bead movements: instantaneous and maximum velocities, run lengths, pause frequencies and pause durations. These measurements provide parameters for a mathematical model that predicts the spatiotemporal evolution of distribution of the two different types of bead cargo in the axon. The results reveal that negatively charged beads differ from APP-C beads in velocity and dispersion, and predict that at long time points APP-C will achieve greater progress towards the presynaptic

  19. Fast preparation and thermal transport property of TiCoSb-based half-Heusler compounds

    NASA Astrophysics Data System (ADS)

    Xie, Wen-Jie; Tang, Xin-Feng; Zhang, Qing-Jie

    2007-11-01

    TiCoSb-based half-Heusler compounds with the substitution of Zr for Ti have been prepared quickly by combining high-energy ball milling method with spark plasma sintering technique, and their thermal transport properties have been investigated. With the increase of the concentration of Zr, the thermal conductivity of Ti1-xZrxCoSb compounds decreases significantly. Compared with the thermal conductivity of TiCoSb compound, that of Ti0.5Zr0.5CoSb decreases by 200% at 1000 K.

  20. Effects of eribulin, vincristine, paclitaxel and ixabepilone on fast axonal transport and kinesin-1 driven microtubule gliding: Implications for chemotherapy-induced peripheral neuropathy

    PubMed Central

    LaPointe, Nichole E.; Morfini, Gerardo; Brady, Scott T.; Feinstein, Stuart C.; Wilson, Leslie; Jordan, Mary Ann

    2014-01-01

    Chemotherapy-induced peripheral neuropathy (CIPN) is a serious, painful and dose-limiting side effect of cancer drugs that target microtubules. The mechanisms underlying the neuronal damage are unknown, but may include disruption of fast axonal transport, an essential microtubule-based process that moves cellular components over long distances between neuronal cell bodies and nerve terminals. This idea is supported by the “dying back” pattern of degeneration observed in CIPN, and by the selective vulnerability of sensory neurons bearing the longest axonal projections. In this study, we test the hypothesis that microtubule-targeting drugs disrupt fast axonal transport using vesicle motility assays in isolated squid axoplasm and a cell-free microtubule gliding assay with defined components. We compare four clinically-used drugs, eribulin, vincristine, paclitaxel and ixabepilone. Of these, eribulin is associated with a relatively low incidence of severe neuropathy, while vincristine has a relatively high incidence. In vesicle motility assays, we found that all four drugs inhibited anterograde (conventional kinesin-dependent) fast axonal transport, with the potency being vincristine = ixabepilone > paclitaxel = eribulin. Interestingly, eribulin and paclitaxel did not inhibit retrograde (cytoplasmic dynein-dependent) fast axonal transport, in contrast to vincristine and ixabepilone. Similarly, vincristine and ixabepilone both exerted significant inhibitory effects in an in vitro microtubule gliding assay consisting of recombinant kinesin (kinesin-1) and microtubules composed of purified bovine brain tubulin, whereas paclitaxel and eribulin had negligible effects. Our results suggest that (i) inhibition of microtubule-based fast axonal transport may be a significant contributor to neurotoxicity induced by microtubule-targeting drugs, and (ii) that individual microtubule-targeting drugs affect fast axonal transport through different mechanisms. PMID:23711742

  1. Techno-Economic Analysis of Biomass Fast Pyrolysis to Transportation Fuels

    SciTech Connect

    Wright, M. M.; Satrio, J. A.; Brown, R. C.; Daugaard, D. E.; Hsu, D. D.

    2010-11-01

    This study develops techno-economic models for assessment of the conversion of biomass to valuable fuel products via fast pyrolysis and bio-oil upgrading. The upgrading process produces a mixture of naphtha-range (gasoline blend stock) and diesel-range (diesel blend stock) products. This study analyzes the economics of two scenarios: onsite hydrogen production by reforming bio-oil, and hydrogen purchase from an outside source. The study results for an nth plant indicate that petroleum fractions in the naphtha distillation range and in the diesel distillation range are produced from corn stover at a product value of $3.09/gal ($0.82/liter) with onsite hydrogen production or $2.11/gal ($0.56/liter) with hydrogen purchase. These values correspond to a $0.83/gal ($0.21/liter) cost to produce the bio-oil. Based on these nth plant numbers, product value for a pioneer hydrogen-producing plant is about $6.55/gal ($1.73/liter) and for a pioneer hydrogen-purchasing plant is about $3.41/gal ($0.92/liter). Sensitivity analysis identifies fuel yield as a key variable for the hydrogen-production scenario. Biomass cost is important for both scenarios. Changing feedstock cost from $50-$100 per short ton changes the price of fuel in the hydrogen production scenario from $2.57-$3.62/gal ($0.68-$0.96/liter).

  2. Laser-driven fast-electron transport in preheated foil targets

    SciTech Connect

    Honrubia, J.J.; Kaluza, M.; Schreiber, J.; Tsakiris, G.D.; Meyer-ter-Vehn, J.

    2005-05-15

    Laser-driven relativistic electron transport through aluminum foils preheated and expanded by amplified spontaneous emission (ASE) prepulses has been studied by means of two- and three-dimensional hybrid particle-in-cell simulations. This study is motivated by recent proton acceleration experiments [M. Kaluza, J. Schreiber, M. I. K. Santala, G. D. Tsakiris, K. Eidmann, J. Meyer-ter-Vehn, and K. J. Witte, Phys. Rev. Lett. 93, 045003 (2004)] showing a significant effect of the ASE prepulse on the proton spectra. Here, it is found that electron-beam collimation due to magnetic fields is reduced and resistive heating by return currents is significantly enhanced, when considering ASE-expanded rather than unperturbed solid target foils. It is shown that this allows for a consistent picture of the new proton spectra and the parameters of the driving electron pulse (angular spread at injection, laser-to-electron conversion, and energy spectrum)

  3. The transport characteristics of passing fast ions produced by nonlocal overlapping of drift island surfaces and magnetic island surfaces

    NASA Astrophysics Data System (ADS)

    Cao, Jinjia; Gong, Xueyu; Xiang, Dong; Huang, Qianhong; Yu, Jun

    2016-08-01

    The structure of the drift-island surface of passing fast ions (PFIs) is investigated in the presence of the resonant interaction with a magnetic island. Two overlapping regions of the drift-island surface and the magnetic island surface are found, one corresponding to local overlapping region and the other to non-local one. Here, the word "nonlocal" denotes that the resonances in the core plasma can have effects on the PFIs near the plasma boundary, while the "local" represents that the PFIs just near the resonant location are influenced. The nonlocal overlapping constructs a transport path along which the PFIs can become losses. There are three kinds of drift-island surfaces to join in forming the transport paths. A pitch angle region, which is called pitch angle gap, is found near the plasma boundary, where the drift-island surface cannot be formed and few PFIs are lost. The pitch-angle selective features of PFI losses are obtained by analyzing the three kinds of drift-island surfaces. The coupling between the crowd drift island surfaces and the collision can induce the prompt losses of PFIs and rapidly slowing down of PFI energy. The time of the prompt losses and the slowing down rate are calculated. Qualitatively, the theoretical results are in well agreement with the experimental observations in ASDEX Upgrade [M. García-Muñoz et al., Nucl. Fusion 47, L10 (2007)].

  4. Radiological transportation risk assessment of the shipment of sodium-bonded fuel from the Fast Flux Test Facility to the Idaho National Engineering Laboratory

    SciTech Connect

    Green, J.R.

    1995-01-31

    This document was written in support of Environmental Assessment: Shutdown of the Fast Flux Test Facility (FFTF), Hanford Site, Richland, Washington. It analyzes the potential radiological risks associated with the transportation of sodium-bonded metal alloy and mixed carbide fuel from the FFTF on the Hanford Site in Washington State to the Idaho Engineering Laboratory in Idaho in the T-3 Cask. RADTRAN 4 is used for the analysis which addresses potential risk from normal transportation and hypothetical accident scenarios.

  5. A fast, parallel algorithm to solve the basic fluvial erosion/transport equations

    NASA Astrophysics Data System (ADS)

    Braun, J.

    2012-04-01

    Quantitative models of landform evolution are commonly based on the solution of a set of equations representing the processes of fluvial erosion, transport and deposition, which leads to predict the geometry of a river channel network and its evolution through time. The river network is often regarded as the backbone of any surface processes model (SPM) that might include other physical processes acting at a range of spatial and temporal scales along hill slopes. The basic laws of fluvial erosion requires the computation of local (slope) and non-local (drainage area) quantities at every point of a given landscape, a computationally expensive operation which limits the resolution of most SPMs. I present here an algorithm to compute the various components required in the parameterization of fluvial erosion (and transport) and thus solve the basic fluvial geomorphic equation, that is very efficient because it is O(n) (the number of required arithmetic operations is linearly proportional to the number of nodes defining the landscape), and is fully parallelizable (the computation cost decreases in a direct inverse proportion to the number of processors used to solve the problem). The algorithm is ideally suited for use on latest multi-core processors. Using this new technique, geomorphic problems can be solved at an unprecedented resolution (typically of the order of 10,000 X 10,000 nodes) while keeping the computational cost reasonable (order 1 sec per time step). Furthermore, I will show that the algorithm is applicable to any regular or irregular representation of the landform, and is such that the temporal evolution of the landform can be discretized by a fully implicit time-marching algorithm, making it unconditionally stable. I will demonstrate that such an efficient algorithm is ideally suited to produce a fully predictive SPM that links observationally based parameterizations of small-scale processes to the evolution of large-scale features of the landscapes on

  6. A fast flux tube-based method for solute-transport simulation

    NASA Astrophysics Data System (ADS)

    Atteia, Olivier; Huberson, Serge; Dupuy, Alain

    2011-03-01

    A new method to calculate the transport of dissolved species in aquifers is presented. This approach is an extension of the stream tubes which are used for flow computation. The flux tubes defined here are conservative for solutes, but not for water mass. The flux tubes are first defined in a general domain and then calculated in a two-dimensional uniform flow field. The tubes' computation is based on a parametric solution. The method is extended further in order to deal with heterogeneous media. A particle-tracking algorithm is used where the deviation of the flux-tube boundaries due to dispersion is accounted for. The approximate solution obtained by this approach is compared to classical numerical solutions given by a finite difference code (RT3D) and a finite element code (FEFLOW). This comparison was performed for several test cases with increasing complexity. The differences between the flux-tube approach and the other methods always remain small, even regarding mass conservation. The major advantage of the flux-tube approach is the ability to reach a solution quickly, as the method is hundreds to thousands of times faster than classical finite difference or finite element models.

  7. Release of kinesin from vesicles by hsc70 and regulation of fast axonal transport

    NASA Technical Reports Server (NTRS)

    Tsai, M. Y.; Morfini, G.; Szebenyi, G.; Brady, S. T.

    2000-01-01

    The nature of kinesin interactions with membrane-bound organelles and mechanisms for regulation of kinesin-based motility have both been surprisingly difficult to define. Most kinesin is recovered in supernatants with standard protocols for purification of motor proteins, but kinesin recovered on membrane-bound organelles is tightly bound. Partitioning of kinesin between vesicle and cytosolic fractions is highly sensitive to buffer composition. Addition of either N-ethylmaleimide or EDTA to homogenization buffers significantly increased the fraction of kinesin bound to organelles. Given that an antibody against kinesin light chain tandem repeats also releases kinesin from vesicles, these observations indicated that specific cytoplasmic factors may regulate kinesin release from membranes. Kinesin light tandem repeats contain DnaJ-like motifs, so the effects of hsp70 chaperones were evaluated. Hsc70 released kinesin from vesicles in an MgATP-dependent and N-ethylmaleimide-sensitive manner. Recombinant kinesin light chains inhibited kinesin release by hsc70 and stimulated the hsc70 ATPase. Hsc70 actions may provide a mechanism to regulate kinesin function by releasing kinesin from cargo in specific subcellular domains, thereby effecting delivery of axonally transported materials.

  8. Pressure-induced inhibition of fast axonal transport of proteins in the rabbit vagus nerve in galactose neuropathy: prevention by an aldose reductase inhibitor.

    PubMed

    McLean, W G

    1988-07-01

    Fast and slow anterograde axonal transport and retrograde axonal transport of proteins were studied in the mainly non-myelinated sensory fibres of the vagus nerve of rabbits fed a diet of 50% galactose over a period of 29 days. Galactose feeding had no effect on the rate or protein composition of slow transport nor on the amount of retrogradely transported proteins. There was a slight retardation of fast transported proteins although their composition was unchanged. The galactose feeding led to a significant increase (p less than 0.005) in nerve water content and nerve galactitol but no significant change in myo-inositol. When 20 mm Hg pressure was applied locally to the cervical vagus nerve, fast transported proteins accumulated proximal to the compression zone in the galactose-fed but not in control rabbits. Administration of the aldose reductase inhibitor Statil (ICI 128436) throughout the experiment prevented the increased susceptibility to pressure and the increase in nerve galactitol and water content. The effects of pressure are similar to those found in the streptozotocin-diabetic rat although the underlying mechanisms may differ.

  9. Sink fast and swim harder! Round-trip cost-of-transport for buoyant divers.

    PubMed

    Miller, Patrick J O; Biuw, Martin; Watanabe, Yuuki Y; Thompson, Dave; Fedak, Mike A

    2012-10-15

    Efficient locomotion between prey resources at depth and oxygen at the surface is crucial for breath-hold divers to maximize time spent in the foraging layer, and thereby net energy intake rates. The body density of divers, which changes with body condition, determines the apparent weight (buoyancy) of divers, which may affect round-trip cost-of-transport (COT) between the surface and depth. We evaluated alternative predictions from external-work and actuator-disc theory of how non-neutral buoyancy affects round-trip COT to depth, and the minimum COT speed for steady-state vertical transit. Not surprisingly, the models predict that one-way COT decreases (increases) when buoyancy aids (hinders) one-way transit. At extreme deviations from neutral buoyancy, gliding at terminal velocity is the minimum COT strategy in the direction aided by buoyancy. In the transit direction hindered by buoyancy, the external-work model predicted that minimum COT speeds would not change at greater deviations from neutral buoyancy, but minimum COT speeds were predicted to increase under the actuator disc model. As previously documented for grey seals, we found that vertical transit rates of 36 elephant seals increased in both directions as body density deviated from neutral buoyancy, indicating that actuator disc theory may more closely predict the power requirements of divers affected by gravity than an external work model. For both models, minor deviations from neutral buoyancy did not affect minimum COT speed or round-trip COT itself. However, at body-density extremes, both models predict that savings in the aided direction do not fully offset the increased COT imposed by the greater thrusting required in the hindered direction. PMID:23014571

  10. A role for cyclin-dependent kinase(s) in the modulation of fast anterograde axonal transport: effects defined by olomoucine and the APC tumor suppressor protein

    NASA Technical Reports Server (NTRS)

    Ratner, N.; Bloom, G. S.; Brady, S. T.

    1998-01-01

    Proteins that interact with both cytoskeletal and membrane components are candidates to modulate membrane trafficking. The tumor suppressor proteins neurofibromin (NF1) and adenomatous polyposis coli (APC) both bind to microtubules and interact with membrane-associated proteins. The effects of recombinant NF1 and APC fragments on vesicle motility were evaluated by measuring fast axonal transport along microtubules in axoplasm from squid giant axons. APC4 (amino acids 1034-2844) reduced only anterograde movements, whereas APC2 (aa 1034-2130) or APC3 (aa 2130-2844) reduced both anterograde and retrograde transport. NF1 had no effect on organelle movement in either direction. Because APC contains multiple cyclin-dependent kinase (CDK) consensus phosphorylation motifs, the kinase inhibitor olomoucine was examined. At concentrations in which olomoucine is specific for cyclin-dependent kinases (5 microM), it reduced only anterograde transport, whereas anterograde and retrograde movement were both affected at concentrations at which other kinases are inhibited as well (50 microM). Both anterograde and retrograde transport also were inhibited by histone H1 and KSPXK peptides, substrates for proline-directed kinases, including CDKs. Our data suggest that CDK-like axonal kinases modulate fast anterograde transport and that other axonal kinases may be involved in modulating retrograde transport. The specific effect of APC4 on anterograde transport suggests a model in which the binding of APC to microtubules may limit the activity of axonal CDK kinase or kinases in restricted domains, thereby affecting organelle transport.

  11. Fast-ion transport in q{sub min}>2, high-β steady-state scenarios on DIII-D

    SciTech Connect

    Holcomb, C. T.; Heidbrink, W. W.; Collins, C.; Ferron, J. R.; Van Zeeland, M. A.; Garofalo, A. M.; Bass, E. M.; Luce, T. C.; Pace, D. C.; Solomon, W. M.; Mueller, D.; Grierson, B.; Podesta, M.; Gong, X.; Ren, Q.; Park, J. M.; Kim, K.; Turco, F.

    2015-05-15

    Results from experiments on DIII-D [J. L. Luxon, Fusion Sci. Technol. 48, 828 (2005)] aimed at developing high β steady-state operating scenarios with high-q{sub min} confirm that fast-ion transport is a critical issue for advanced tokamak development using neutral beam injection current drive. In DIII-D, greater than 11 MW of neutral beam heating power is applied with the intent of maximizing β{sub N} and the noninductive current drive. However, in scenarios with q{sub min}>2 that target the typical range of q{sub 95}= 5–7 used in next-step steady-state reactor models, Alfvén eigenmodes cause greater fast-ion transport than classical models predict. This enhanced transport reduces the absorbed neutral beam heating power and current drive and limits the achievable β{sub N}. In contrast, similar plasmas except with q{sub min} just above 1 have approximately classical fast-ion transport. Experiments that take q{sub min}>3 plasmas to higher β{sub P} with q{sub 95}= 11–12 for testing long pulse operation exhibit regimes of better than expected thermal confinement. Compared to the standard high-q{sub min} scenario, the high β{sub P} cases have shorter slowing-down time and lower ∇β{sub fast}, and this reduces the drive for Alfvénic modes, yielding nearly classical fast-ion transport, high values of normalized confinement, β{sub N}, and noninductive current fraction. These results suggest DIII-D might obtain better performance in lower-q{sub 95}, high-q{sub min} plasmas using broader neutral beam heating profiles and increased direct electron heating power to lower the drive for Alfvén eigenmodes.

  12. Enhanced Dopamine Release by Dopamine Transport Inhibitors Described by a Restricted Diffusion Model and Fast-Scan Cyclic Voltammetry.

    PubMed

    Hoffman, Alexander F; Spivak, Charles E; Lupica, Carl R

    2016-06-15

    Fast-scan cyclic voltammetry (FSCV) using carbon fiber electrodes is widely used to rapidly monitor changes in dopamine (DA) levels in vitro and in vivo. Current analytical approaches utilize parameters such as peak oxidation current amplitude and decay times to estimate release and uptake processes, respectively. However, peak amplitude changes are often observed with uptake inhibitors, thereby confounding the interpretation of these parameters. To overcome this limitation, we demonstrate that a simple five-parameter, two-compartment model mathematically describes DA signals as a balance of release (r/ke) and uptake (ku), summed with adsorption (kads and kdes) of DA to the carbon electrode surface. Using nonlinear regression, we demonstrate that our model precisely describes measured DA signals obtained in brain slice recordings. The parameters extracted from these curves were then validated using pharmacological manipulations that selectively alter vesicular release or DA transporter (DAT)-mediated uptake. Manipulation of DA release through altering the Ca(2+)/Mg(2+) ratio or adding tetrodotoxin reduced the release parameter with no effect on the uptake parameter. DAT inhibitors methylenedioxypyrovalerone, cocaine, and nomifensine significantly reduced uptake and increased vesicular DA release. In contrast, a low concentration of amphetamine reduced uptake but had no effect on DA release. Finally, the kappa opioid receptor agonist U50,488 significantly reduced vesicular DA release but had no effect on uptake. Together, these data demonstrate a novel analytical approach to distinguish the effects of manipulations on DA release or uptake that can be used to interpret FSCV data. PMID:27018734

  13. Impact of Pre-Plasma on Fast Electron Generation and Transport from Short Pulse High Intensity Lasers

    NASA Astrophysics Data System (ADS)

    Peebles, J.; McGuffey, C.; Krauland, C.; Jarrott, L. C.; Sorokovikova, A.; Qiao, B.; Krasheninnikov, S.; Beg, F. N.; Wei, M. S.; Park, J.; Link, A.; Chen, H.; McLean, H. S.; Wagner, C.; Minello, V.; McCary, E.; Meadows, A.; Spinks, M.; Gaul, E.; Dyer, G.; Hegelich, B. M.; Martinez, M.; Donovan, M.; Ditmire, T.

    2014-10-01

    We present the results and analysis from recent short pulse laser matter experiments using the Texas Petawatt Laser to study the impact of pre-plasma on fast electron generation and transport. The experimental setup consisted of 3 separate beam elements: a main, high intensity, short pulse beam for the interaction, a secondary pulse of equal intensity interacting with a separate thin foil target to generate protons for side-on proton imaging and a third, low intensity, wider beam to generate a varied scale length pre-plasma. The main target consisted of a multilayer planar Al foil with a buried Cu fluor layer. The electron beam was characterized with multiple diagnostics, including several bremsstrahlung spectrometers, magnetic electron spectrometers and Cu-K α imaging. The protons from the secondary target were used to image the fields on the front of the target in the region of laser plasma interaction. Features seen in the interaction region by these protons will be presented along with characteristics of the generated electron beam. This work performed under the auspices of the US DOE under Contracts DE-FOA-0000583 (FES, NNSA).

  14. The effect of biological shielding on fast neutron and photon transport in the VVER-1000 mock-up model placed in the LR-0 reactor.

    PubMed

    Košťál, Michal; Cvachovec, František; Milčák, Ján; Mravec, Filip

    2013-05-01

    The paper is intended to show the effect of a biological shielding simulator on fast neutron and photon transport in its vicinity. The fast neutron and photon fluxes were measured by means of scintillation spectroscopy using a 45×45 mm(2) and a 10×10 mm(2) cylindrical stilbene detector. The neutron spectrum was measured in the range of 0.6-10 MeV and the photon spectrum in 0.2-9 MeV. The results of the experiment are compared with calculations. The calculations were performed with various nuclear data libraries.

  15. Transcriptome Analysis and Postprandial Expression of Amino Acid Transporter Genes in the Fast Muscles and Gut of Chinese Perch (Siniperca chuatsi)

    PubMed Central

    Chen, Lin; Zeng, Ming; Wu, Yuanan; Wang, Jianhua; Zhang, Jianshe

    2016-01-01

    The characterization of the expression and regulation of growth-related genes in the muscles of Chinese perch is of great interest to aquaculturists because of the commercial value of the species. The transcriptome annotation of the skeletal muscles is a crucial step in muscle growth-related gene analysis. In this study, we generated 52 504 230 reads of mRNA sequence data from the fast muscles of the Chinese perch by using Solexa/Illumina RNA-seq. Twenty-one amino acid transporter genes were annotated by searching protein and gene ontology databases, and postprandial changes in their transcript abundance were assayed after administering a single satiating meal to Chinese perch juveniles (body mass, approximately 100 g), following fasting for 1 week. The gut content of the Chinese perch increased significantly after 1 h and remained high for 6 h following the meal and emptied within 48–96 h. Expression of eight amino acid transporter genes was assayed in the fast muscles through quantitative real-time polymerase chain reaction at 0, 1, 3, 6, 12, 24, 48, and 96 h. Among the genes, five transporter transcripts were markedly up-regulated within 1 h of refeeding, indicating that they may be potential candidate genes involved in the rapid-response signaling system regulating fish myotomal muscle growth. These genes display coordinated regulation favoring the resumption of myogenesis responding to feeding. PMID:27463683

  16. Transcriptome Analysis and Postprandial Expression of Amino Acid Transporter Genes in the Fast Muscles and Gut of Chinese Perch (Siniperca chuatsi).

    PubMed

    Wu, Ping; Li, Yulong; Cheng, Jia; Chen, Lin; Zeng, Ming; Wu, Yuanan; Wang, Jianhua; Zhang, Jianshe; Chu, Wuying

    2016-01-01

    The characterization of the expression and regulation of growth-related genes in the muscles of Chinese perch is of great interest to aquaculturists because of the commercial value of the species. The transcriptome annotation of the skeletal muscles is a crucial step in muscle growth-related gene analysis. In this study, we generated 52 504 230 reads of mRNA sequence data from the fast muscles of the Chinese perch by using Solexa/Illumina RNA-seq. Twenty-one amino acid transporter genes were annotated by searching protein and gene ontology databases, and postprandial changes in their transcript abundance were assayed after administering a single satiating meal to Chinese perch juveniles (body mass, approximately 100 g), following fasting for 1 week. The gut content of the Chinese perch increased significantly after 1 h and remained high for 6 h following the meal and emptied within 48-96 h. Expression of eight amino acid transporter genes was assayed in the fast muscles through quantitative real-time polymerase chain reaction at 0, 1, 3, 6, 12, 24, 48, and 96 h. Among the genes, five transporter transcripts were markedly up-regulated within 1 h of refeeding, indicating that they may be potential candidate genes involved in the rapid-response signaling system regulating fish myotomal muscle growth. These genes display coordinated regulation favoring the resumption of myogenesis responding to feeding. PMID:27463683

  17. Homologue gene of bile acid transporters ntcp, asbt, and ost-alpha in rainbow trout Oncorhynchus mykiss: tissue expression, effect of fasting, and response to bile acid administration.

    PubMed

    Murashita, Koji; Yoshiura, Yasutoshi; Chisada, Shin-Ichi; Furuita, Hirofumi; Sugita, Tsuyoshi; Matsunari, Hiroyuki; Iwashita, Yasuro; Yamamoto, Takeshi

    2014-04-01

    Bile acid transporters belonging to the SLC10A protein family, Na+ taurocholate cotransporting polypeptide (NTCP or SLC10A1), apical sodium-dependent bile salt transporter (ASBT or SLC10A2), and organic solute transporter alpha (Ost-alpha) have been known to play critical roles in the enterohepatic circulation of bile acids in mammals. In this study, ntcp, asbt, and ost-alpha-1/-2 cDNA were cloned, their tissue distributions were characterized, and the effects of fasting and bile acid administration on their expression were examined in rainbow trout Oncorhynchus mykiss. The structural characteristics of Ntcp, Asbt, and Ost-alpha were well conserved in trout, and three-dimensional structure analysis showed that Ntcp and Asbt were similar to each other. Tissue distribution analysis revealed that trout asbt was primarily expressed in the hindgut, while ntcp expression occurred in the brain, and ost-alpha-1/-2 was mainly expressed in the liver or ovary. Although asbt and ost-alpha-1 mRNA levels in the gut increased in response to fasting for 4 days, ost-alpha-1 expression in the liver decreased. Similarly, bile acid administration increased asbt and ost-alpha-1 expression levels in the gut, while those of ntcp and ost-alpha-2 in the liver decreased. These results suggested that the genes asbt, ntcp, and ost-alpha are involved in bile acid transport in rainbow trout.

  18. Fast ion transport and phase separation in a mechanically driven flow of electrolytes through tortuous sub-nanometer nanochannels.

    PubMed

    Liu, Ling; Chen, Xi

    2013-08-01

    Both nanostructured materials and nanotubes hold tremendous promises for separation and purification applications, such as water desalination. By using molecular dynamics, herein, we compare the transport of aqueous electrolyte solutions through a Y-zeolite, which features interconnected, tortuous sub-nanometer nanopores, and a model silica nanotube, which has the same composition but is straight and has much lower surface complexity. In the Y-zeolite, ion transport is faster than the transport of water molecules, thus leading to a phenomenon of phase separation in which a gradient of salt concentration is generated along the flow direction. However, similar transport characteristics and phase separation are not found in the model silica nanotube. Detailed analysis suggests that, in nanochannels with complicated geometries, such as those of the Y-zeolite, the structural and flow characteristics of confined nanofluids are highly coupled, thus influencing the transport of ions and solvents and causing the phenomenon of phase separation.

  19. Post-scram Liquid Metal cooled Fast Breeder Reactor (LMFBR) neat transport system dynamics and steam generator control

    NASA Astrophysics Data System (ADS)

    Brukx, J. F. L. M.

    1982-06-01

    Loop type LMFBR heat transport system dynamics after reactor shutdown and during subsequent decay heat removal are considered with emphasis on steam generator dynamics including the development and evaluation of various post-scram steam generator control systems, and natural circulation of the sodium coolant, including the influence of superimposed free convection on forced convection heat transfer and pressure drop. The normal operating and decay heat removal functions of the overall heat transport system are described.

  20. Post-scram Liquid Metal cooled Fast Breeder Reactor (LMFBR) heat transport system dynamics and steam generator control: Figures

    NASA Astrophysics Data System (ADS)

    Brukx, J. F. L. M.

    1982-06-01

    Dynamic modeling of LMFBR heat transport system is discussed. Uncontrolled transient behavior of individual components and of the integrated heat transport system are considered. For each component, results showing specific dynamic features of the component and/or model capability were generated. Controlled dynamic behavior for alternative steam generator control systems during forced and natural sodium coolant circulation was analyzed. Combined free and forced convection of laminar and turbulent vertical pipe flow of liquid metals was investigated.

  1. Differential screening of mutated SOD1 transgenic mice reveals early up-regulation of a fast axonal transport component in spinal cord motor neurons.

    PubMed

    Dupuis, L; de Tapia, M; René, F; Lutz-Bucher, B; Gordon, J W; Mercken, L; Pradier, L; Loeffler, J P

    2000-08-01

    In the present study we analyze the molecular mechanisms underlying motor neuron degeneration in familial amyotrophic lateral sclerosis (FALS). For this, we used a transgenic mouse model expressing the Cu/Zn superoxide dismutase (SOD1) gene with a Gly(86) to Arg (G86R) mutation equivalent to that found in a subset of human FALS. Using an optimized suppression subtractive hybridization method, a cDNA specifically up-regulated during the asymptomatic phase in the lumbar spinal cord of G86R mice was identified by sequence analysis as the KIF3-associated protein (KAP3), a regulator of fast axonal transport. RT-PCR analysis revealed that KAP3 induction was an early event arising long before axonal degeneration. Immunohistochemical studies further revealed that KAP3 protein predominantly accumulates in large motor neurons of the ventral spinal cord. We further demonstrated that KAP3 up-regulation occurs independent of any change in the other components of the kinesin II complex. However, since the ubiquitous KIF1A motor is up-regulated, our results show an early and complex rearrangement of the fast axonal transport machinery in the course of FALS pathology.

  2. Biorelevant media for transport experiments in the Caco-2 model to evaluate drug absorption in the fasted and the fed state and their usefulness.

    PubMed

    Markopoulos, C; Thoenen, F; Preisig, D; Symillides, M; Vertzoni, M; Parrott, N; Reppas, C; Imanidis, G

    2014-04-01

    In this work we developed and characterized transport media that simulate the composition of micellar phase of intestinal fluids in the fasted and, especially, in the fed state and are appropriate for evaluating intestinal drug permeability characteristics using the Caco-2 model (FaSSIF-TM(Caco) and FeSSIF-TM(Caco), respectively). Media composition was based on FaSSIF-V2 and FeSSIF-V2 and recently reported data on total lipid concentrations in the micellar phase of contents of the upper small intestine in the fasted and the fed state and was adapted for cell culture compatibility. Permeation data were evaluated by compartmental kinetic modeling. Permeability coefficients, P, of hydrophilic drugs were not affected by media composition. In contrast, P values of a series of lipophilic compounds measured with FaSSIF-TM(Caco) and FeSSIF-TM(Caco), and reflecting transport by diffusion were smaller than those obtained with a purely aqueous reference transport medium, aq-TM(Caco), following the rank order aq-TM(Caco)>FaSSIF-TM(Caco)>FeSSIF-TM(Caco). The decline of permeability values was stronger as lipophilicity of the compounds increased. Compared with values estimated using aq-TM(Caco), permeability was reduced, depending on the compound, by more than 20- to 100-fold when measured with FeSSIF-TM(Caco) whereas compound ranking in regard to the permeability characteristics was also affected. The impact of reduced P value on flux through the mucosa, hence on drug absorption, in combination with the drug amount loaded on colloidal particles needs to be taken into consideration in PBPK modeling especially when the food effect is evaluated.

  3. Transportation.

    ERIC Educational Resources Information Center

    Crank, Ron

    This instructional unit is one of 10 developed by students on various energy-related areas that deals specifically with transportation and energy use. Its objective is for the student to be able to discuss the implication of energy usage as it applies to the area of transportation. Some topics covered are efficiencies of various transportation…

  4. The China Clipper - Fast advective transport of radon-rich air from the Asian boundary layer to the upper troposphere near California

    NASA Technical Reports Server (NTRS)

    Kritz, Mark A.; Le Roulley, Jean-Claude; Danielsen, Edwin F.

    1990-01-01

    A series of upper tropospheric radon concentration measurements made over the eastern Pacific and west coast of the U.S. during the summers of 1983 and 1984 has revealed the occurrence of unexpectedly high radon concentrations for 9 of the 61 measurements. A frequency distribution plot of the set of 61 observations shows a distinct bimodal distribution, with approximately 2/5 of the observations falling close to 1 pCi/SCM, and 3/5 falling in a high concentration mode centered at about 11 pCi/SCM. Trajectory and synoptic analyses for two of the flights on which such high radon concentrations were observed indicate that this radon-rich air originated in the Asian boundary layer, ascended in cumulus updrafts, and was carried eastward in the fast moving air on the anticyclonic side of the upper tropospheric jet. The results suggest that the combination of rapid vertical transport from the surface boundary layer to the upper troposphere, followed by rapid horizontal transport eastward represents an efficient mode of long-transport for other, chemically reactive atmospheric trace constituents.

  5. A fast long-range transport model for operational use in episode simulation. Application to the Chernobyl accident

    NASA Astrophysics Data System (ADS)

    Bonelli, P.; Calori, G.; Finzi, G.

    A simple Lagrangian puff trajectory model and its software implementation, STRALE, are described. Standard meteorological data are used as input for the simulation of the three-dimensional atmospheric transport and dispersion of a pollutant released by a point source. The schemes adopted to describe the vertical diffusion and the interaction with the mixing layer are discussed on the basis of the comparison between simulated and measured 137Cs activities for the Chernobyl nuclear accident.

  6. Risk assessment of the fatality due to explosion in land mass transport infrastructure by fast transient dynamic analysis.

    PubMed

    Giannopoulos, G; Larcher, M; Casadei, F; Solomos, G

    2010-01-15

    Terrorist attacks in New York have shocked the world community showing clearly the vulnerability of air transport in such events. However, the terrorist attacks in Madrid and London showed that land mass transport infrastructure is equally vulnerable in case of similar attacks. The fact that there has not been substantial investment in the domain of risk analysis and evaluation of the possible effects due to such events in land mass transportation infrastructure leaves large room for new developments that could eventually fill this gap. In the present work using the finite element code EUROPLEXUS there has been a large effort to perform a complete study of the land mass infrastructure in case of explosion events. This study includes a train station, a metro station and a metro carriage providing thus valuable simulation data for a variety of different situations. For the analysis of these structures it has been necessary to apply a laser scanning method for the acquisition of geometrical data, to improve the simulation capabilities of EUROPLEXUS by adding failure capabilities for specific finite elements, to implement new material models (e.g. glass), and to add new modules that achieve data post-processing for the calculation of fatal and non-fatal injuries risk. The aforementioned improvements are explained in the present work with emphasis in the newly developed risk analysis features of EUROPLEXUS.

  7. Fast Neutron Transport in the Biological Shielding Model and Other Regions of the VVER-1000 Mock-Up on the LR-0 Research Reactor

    NASA Astrophysics Data System (ADS)

    Košťál, Michal; Milčák, Ján; Cvachovec, František; Jánský, Bohumil; Rypar, Vojtěch; Juříček, Vlastimil; Novák, Evžen; Egorov, Alexander; Zaritskiy, Sergey

    2016-02-01

    A set of benchmark experiments was carried out in the full scale VVER-1000 mock-up on the reactor LR-0 in order to validate neutron transport calculation methodologies and to perform the optimization of the shape and locations of neutron flux operation monitors channels inside the shielding of the new VVER-1000 type reactors. Compared with previous experiments on the VVER-1000 mock-up on the reactor LR-0, the fast neutron spectra were measured in the extended neutron energy interval (0.1-10 MeV) and new calculations were carried out with the MCNPX code using various nuclear data libraries (ENDF/B VII.0, JEFF 3.1, JENDL 3.3, JENDL 4, ROSFOND 2009, and CENDL 3.1). Measurements and calculations were carried out at different points in the mock-up. The calculation and experimental data are compared.

  8. Investigations on the heat transport capability of a cryogenic oscillating heat pipe and its application in achieving ultra-fast cooling rates for cell vitrification cryopreservation☆

    PubMed Central

    Han, Xu; Ma, Hongbin; Jiao, Anjun; Critser, John K.

    2010-01-01

    Theoretically, direct vitrification of cell suspensions with relatively low concentrations (~1 M) of permeating cryoprotective agents (CPA) is suitable for cryopreservation of almost all cell types and can be accomplished by ultra-fast cooling rates that are on the order of 106–7 K/min. However, the methods and devices currently available for cell cryopreservation cannot achieve such high cooling rates. In this study, we constructed a novel cryogenic oscillating heat pipe (COHP) using liquid nitrogen as its working fluid and investigated its heat transport capability to assess its application for achieving ultra-fast cooling rates for cell cryopreservation. The experimental results showed that the apparent heat transfer coefficient of the COHP can reach 2 × 105 W/m2·K, which is two orders of the magnitude higher than traditional heat pipes. Theoretical analyzes showed that the average local heat transfer coefficient in the thin film evaporation region of the COHP can reach 1.2 × 106 W/m2·K, which is approximately 103 times higher than that achievable with standard pool-boiling approaches. Based on these results, a novel device design applying the COHP and microfabrication techniques is proposed and its efficiency for cell vitrification is demonstrated through numerical simulation. The estimated average cooling rates achieved through this approach is 106–7 K/min, which is much faster than the currently available methods and sufficient for achieving vitrification with relatively low concentrations of CPA. PMID:18430413

  9. N-Substituted Benztropine Analogs: Selective Dopamine Transporter Ligands with a Fast Onset of Action and Minimal Cocaine-Like Behavioral Effects

    PubMed Central

    Li, Su-Min; Kopajtic, Theresa A.; O'Callaghan, Matthew J.; Agoston, Gregory E.; Cao, Jianjing; Newman, Amy Hauck

    2011-01-01

    Previous studies suggested that differences between the behavioral effects of cocaine and analogs of benztropine were related to the relatively slow onset of action of the latter compounds. Several N-substituted benztropine analogs with a relatively fast onset of effects were studied to assess whether a fast onset of effects would render the effects more similar to those of cocaine. Only one of the compounds increased locomotor activity, and the increases were modest compared with those of 10 to 20 mg/kg cocaine. In rats trained to discriminate 10 mg/kg cocaine from saline none of the compounds produced more than 40% cocaine-like responds up to 2 h after injection. None of the compounds produced place-conditioning when examined up to 90 min after injection, indicating minimal abuse liability. The compounds had 5.6 to 30 nM affinities at the dopamine transporter (DAT), with uniformly lower affinities at norepinephrine and serotonin transporters (from 490-4600 and 1420–7350 nM, respectively). Affinities at muscarinic M1 receptors were from 100- to 300-fold lower than DAT affinities, suggesting minimal contribution of those sites to the behavioral effects of the compounds. Affinities at histaminic H1 sites were from 11- to 43-fold lower than those for the DAT. The compounds also had affinity for sigma, 5-hydroxytryptamine1 (5-HT1), and 5-HT2 receptors that may have contributed to their behavioral effects. Together, the results indicate that a slow onset of action is not a necessary condition for reduced cocaine-like effects of atypical DAT ligands and suggest several mechanisms that may contribute to the reduced cocaine-like efficacy of these compounds. PMID:21088247

  10. Dislocations in SrTiO3: easy to reduce but not so fast for oxygen transport.

    PubMed

    Marrocchelli, Dario; Sun, Lixin; Yildiz, Bilge

    2015-04-15

    The effect of dislocations on the chemical, electrical and transport properties in oxide materials is important for electrochemical devices, such as fuel cells and resistive switches, but these effects have remained largely unexplored at the atomic level. In this work, by using large-scale atomistic simulations, we uncover how a ⟨100⟩{011} edge dislocation in SrTiO3, a prototypical perovskite oxide, impacts the local defect chemistry and oxide ion transport. We find that, in the dilute limit, oxygen vacancy formation energy in SrTiO3 is lower at sites close to the dislocation core, by as much as 2 eV compared to that in the bulk. We show that the formation of a space-charge zone based on the redistribution of charged oxygen vacancies can be captured quantitatively at atomistic level by mapping the vacancy formation energies around the dislocation. Oxide-ion diffusion was studied for a low vacancy concentration regime (ppm level) and a high vacancy concentration regime (up to 2.5%). In both cases, no evidence of pipe-diffusion, i.e., significantly enhanced mobility of oxide ions, was found as determined from the calculated migration barriers, contrary to the case in metals. However, in the low vacancy concentration regime, the vacancy accumulation at the dislocation core gives rise to a higher diffusion coefficient, even though the oxide-ion mobility itself is lower than that in the bulk. Our findings have important implications for applications of perovskite oxides for information and energy technologies. The observed lower oxygen vacancy formation energy at the dislocation core provides a quantitative and direct explanation for the electronic conductivity of dislocations in SrTiO3 and related oxides studied for red-ox based resistive switching. Reducibility and electronic transport at dislocations can also be quantitatively engineered into active materials for fuel cells, catalysis, and electronics.

  11. The Shortlist Method for fast computation of the Earth Mover's Distance and finding optimal solutions to transportation problems.

    PubMed

    Gottschlich, Carsten; Schuhmacher, Dominic

    2014-01-01

    Finding solutions to the classical transportation problem is of great importance, since this optimization problem arises in many engineering and computer science applications. Especially the Earth Mover's Distance is used in a plethora of applications ranging from content-based image retrieval, shape matching, fingerprint recognition, object tracking and phishing web page detection to computing color differences in linguistics and biology. Our starting point is the well-known revised simplex algorithm, which iteratively improves a feasible solution to optimality. The Shortlist Method that we propose substantially reduces the number of candidates inspected for improving the solution, while at the same time balancing the number of pivots required. Tests on simulated benchmarks demonstrate a considerable reduction in computation time for the new method as compared to the usual revised simplex algorithm implemented with state-of-the-art initialization and pivot strategies. As a consequence, the Shortlist Method facilitates the computation of large scale transportation problems in viable time. In addition we describe a novel method for finding an initial feasible solution which we coin Modified Russell's Method. PMID:25310106

  12. A general continuum approach to describe fast electronic transport in pulsed laser irradiated materials: the problem of Coulomb explosion

    NASA Astrophysics Data System (ADS)

    Bulgakova, Nadezhda M.; Stoian, Razvan; Rosenfeld, Arkadi; Marine, Wladimir; Campbell, Eleanor E.

    2004-09-01

    We present a continuum model, based on a drift-diffusion approach, aimed to describe the dynamics of electronic excitation, heating and charge-carrier transport in different materials (metals, semiconductors, and dielectrics) under femtosecond and nanosecond pulsed laser irradiation. The laser-induced charging of the targets is investigated at laser intensities above the material removal threshold. It is demonstrated that, under near-infrared femtosecond irradiation regimes, charging of dielectric surfaces causes a sub-picosecond electrostatic rupture of the superficial layers, alternatively called Coulomb explosion (CE), while this effect is strongly inhibited for metals and semiconductors as a consequence of superior carrier transport properties. On the other hand, simulations of UV nanosecond pulsed laser interaction with bulk silicon have pointed out the possibility of Coulomb explosion in semiconductors. For such regimes a simple analytical theory for the threshold laser fluence of CE has been developed, showing results in agreement with the experimental observations. Various related aspects concerning the possibility of CE depending on different irradiation parameters (fluence, wavelength and pulse duration) are discussed. This includes the temporal and spatial dynamics of charge-carrier generation in non-metallic targets and evolution of the reflection and absorption characteristics.

  13. A general continuum approach to describe fast electronic transport in pulsed laser irradiated materials: The problem of Coulomb explosion

    NASA Astrophysics Data System (ADS)

    Bulgakova, N. M.; Stoian, R.; Rosenfeld, A.; Hertel, I. V.; Marine, W.; Campbell, E. E. B.

    2005-07-01

    We present a continuum model, based on a drift-diffusion approach, aimed at describing the dynamics of electronic excitation, heating, and charge-carrier transport in different materials (metals, semiconductors, and dielectrics) under femtosecond and nanosecond pulsed laser irradiation. The laser-induced charging of the targets is investigated at laser intensities above the material removal threshold. It is demonstrated that, for near-infrared femtosecond irradiation, charging of dielectric surfaces causes a sub-picosecond electrostatic rupture of the superficial layers, alternatively called Coulomb explosion (CE), while this effect is strongly inhibited for metals and semiconductors as a consequence of superior carrier transport properties. On the other hand, application of the model to UV nanosecond pulsed laser interaction with bulk silicon has pointed out the possibility of Coulomb explosion in semiconductors. For such regimes a simple analytical theory for the threshold laser fluence of CE has been developed, showing results in agreement with the experimental observations. Various related aspects concerning the possibility of CE depending on different irradiation parameters (fluence, wavelength and pulse duration) and material properties are discussed. This includes the temporal and spatial dynamics of charge-carrier generation in non-metallic targets and evolution of the reflection and absorption characteristics.

  14. The Shortlist Method for fast computation of the Earth Mover's Distance and finding optimal solutions to transportation problems.

    PubMed

    Gottschlich, Carsten; Schuhmacher, Dominic

    2014-01-01

    Finding solutions to the classical transportation problem is of great importance, since this optimization problem arises in many engineering and computer science applications. Especially the Earth Mover's Distance is used in a plethora of applications ranging from content-based image retrieval, shape matching, fingerprint recognition, object tracking and phishing web page detection to computing color differences in linguistics and biology. Our starting point is the well-known revised simplex algorithm, which iteratively improves a feasible solution to optimality. The Shortlist Method that we propose substantially reduces the number of candidates inspected for improving the solution, while at the same time balancing the number of pivots required. Tests on simulated benchmarks demonstrate a considerable reduction in computation time for the new method as compared to the usual revised simplex algorithm implemented with state-of-the-art initialization and pivot strategies. As a consequence, the Shortlist Method facilitates the computation of large scale transportation problems in viable time. In addition we describe a novel method for finding an initial feasible solution which we coin Modified Russell's Method.

  15. The Shortlist Method for Fast Computation of the Earth Mover's Distance and Finding Optimal Solutions to Transportation Problems

    PubMed Central

    Gottschlich, Carsten; Schuhmacher, Dominic

    2014-01-01

    Finding solutions to the classical transportation problem is of great importance, since this optimization problem arises in many engineering and computer science applications. Especially the Earth Mover's Distance is used in a plethora of applications ranging from content-based image retrieval, shape matching, fingerprint recognition, object tracking and phishing web page detection to computing color differences in linguistics and biology. Our starting point is the well-known revised simplex algorithm, which iteratively improves a feasible solution to optimality. The Shortlist Method that we propose substantially reduces the number of candidates inspected for improving the solution, while at the same time balancing the number of pivots required. Tests on simulated benchmarks demonstrate a considerable reduction in computation time for the new method as compared to the usual revised simplex algorithm implemented with state-of-the-art initialization and pivot strategies. As a consequence, the Shortlist Method facilitates the computation of large scale transportation problems in viable time. In addition we describe a novel method for finding an initial feasible solution which we coin Modified Russell's Method. PMID:25310106

  16. Fast calculation of molecular polar surface area as a sum of fragment-based contributions and its application to the prediction of drug transport properties.

    PubMed

    Ertl, P; Rohde, B; Selzer, P

    2000-10-01

    Molecular polar surface area (PSA), i.e., surface belonging to polar atoms, is a descriptor that was shown to correlate well with passive molecular transport through membranes and, therefore, allows prediction of transport properties of drugs. The calculation of PSA, however, is rather time-consuming because of the necessity to generate a reasonable 3D molecular geometry and the calculation of the surface itself. A new approach for the calculation of the PSA is presented here, based on the summation of tabulated surface contributions of polar fragments. The method, termed topological PSA (TPSA), provides results which are practically identical with the 3D PSA (the correlation coefficient between 3D PSA and fragment-based TPSA for 34 810 molecules from the World Drug Index is 0.99), while the computation speed is 2-3 orders of magnitude faster. The new methodology may, therefore, be used for fast bioavailability screening of virtual libraries having millions of molecules. This article describes the new methodology and shows the results of validation studies based on sets of published absorption data, including intestinal absorption, Caco-2 monolayer penetration, and blood-brain barrier penetration.

  17. R_transport_matrices of the Fast Extraction Beam (FEB) of the AGS, and Beam Parameters at the Starting point of the AtR Line

    SciTech Connect

    Tsoupas,N.; MacKay, W.W.; Satogata, T.; Glenn, W.; Ahrens, L.; Brown, K.; Gardner, C.; Tanaka, S.

    2008-01-01

    As part of the task to improve and further automate the 'AtR BPM Application' we provide the theoretically calculated R-transport-matrices for the following beam line sections, which are shown schematically in Figure 1: (a) the Fast Extraction Beam section (FEB) of the AGS synchrotron. The FEB section starts at the middle of the GlO-kicker and ends at the middle of the H1 0{_}septum. (b) the Drift Extraction Channel (DEC) section of the AGS synchrotron. The DEC section starts at the middle of the H10{_}septum, continues along the fringe field region of the H11,H12, and H13 AGS main magnets, and ends at the starting point of the AtR line. The knowledge of these R-transport-matrices are needed in order to calculate the beam parameters at the beginning of the AtR line, which in turn, are required to calculate the magnet settings of the U{_}line, that match the U{_}line into the W{_}line. Also by incorporating these R{_}matrices into the model of the AtR line, the G10 kicker and the H10 septum are included in the AtR model therefore one can investigate any 'jitter' of either the GlO{_}kicker or HlO{_}septum by looking at the trajectory of the beam in the AtR line.

  18. Status report on the Small Secure Transportable Autonomous Reactor (SSTAR) /Lead-cooled Fast Reactor (LFR) and supporting research and development.

    SciTech Connect

    Sienicki, J. J.; Moisseytsev, A.; Yang, W. S.; Wade, D. C.; Nikiforova, A.; Hanania, P.; Ryu, H. J.; Kulesza, K. P.; Kim, S. J.; Halsey, W. G.; Smith, C. F.; Brown, N. W.; Greenspan, E.; de Caro, M.; Li, N.; Hosemann, P.; Zhang, J.; Yu, H.; Nuclear Engineering Division; LLNL; LANL; Massachusetts Inst. of Tech.; Ecole des Mines de Paris; Oregon State Univ.; Univ.of California at Berkley

    2008-06-23

    This report provides an update on development of a pre-conceptual design for the Small Secure Transportable Autonomous Reactor (SSTAR) Lead-Cooled Fast Reactor (LFR) plant concept and supporting research and development activities. SSTAR is a small, 20 MWe (45 MWt), natural circulation, fast reactor plant for international deployment concept incorporating proliferation resistance for deployment in non-fuel cycle states and developing nations, fissile self-sufficiency for efficient utilization of uranium resources, autonomous load following making it suitable for small or immature grid applications, and a high degree of passive safety further supporting deployment in developing nations. In FY 2006, improvements have been made at ANL to the pre-conceptual design of both the reactor system and the energy converter which incorporates a supercritical carbon dioxide Brayton cycle providing higher plant efficiency (44 %) and improved economic competitiveness. The supercritical CO2 Brayton cycle technology is also applicable to Sodium-Cooled Fast Reactors providing the same benefits. One key accomplishment has been the development of a control strategy for automatic control of the supercritical CO2 Brayton cycle in principle enabling autonomous load following over the full power range between nominal and essentially zero power. Under autonomous load following operation, the reactor core power adjusts itself to equal the heat removal from the reactor system to the power converter through the large reactivity feedback of the fast spectrum core without the need for motion of control rods, while the automatic control of the power converter matches the heat removal from the reactor to the grid load. The report includes early calculations for an international benchmarking problem for a LBE-cooled, nitride-fueled fast reactor core organized by the IAEA as part of a Coordinated Research Project on Small Reactors without Onsite Refueling; the calculations use the same neutronics

  19. Fast transporting ZnO-TiO2 coaxial photoanodes for dye-sensitized solar cells based on ALD-modified SiO2 aerogel frameworks.

    PubMed

    Williams, Vennesa O; Jeong, Nak Cheon; Prasittichai, Chaiya; Farha, Omar K; Pellin, Michael J; Hupp, Joseph T

    2012-07-24

    A doubly coaxial photoanode architecture based on templated SiO(2) aerogels was fabricated on transparent conducting oxides for use in dye-sensitized solar cells (DSSCs). These templates were coated with ZnO via atomic layer deposition (ALD) to yield an electronically interconnected, low-density, high-surface-area, semiconductor framework. Addition of a thin conformal layer of a second metal oxide (alumina, zirconia, or titania) via ALD was found to suppress the dissolution of ZnO that otherwise occurs when it is soaked in alcohol solutions containing acidic dyes used for sensitization or in acetonitrile solutions containing a pyridine derivative and the iodide/tri-iodide (I(-)/I(-)(3)) redox shuttle. Electron transport in SiO(2)-ZnO-TiO(2) photoelectrodes was found to be nearly 2 orders of magnitude faster than in SiO(2)-TiO(2) structures, implying that the interior ZnO sheath serves as the primary electron conduit. In contrast, rates of electron interception by the oxidized form of the redox shuttle were observed to decrease when a TiO(2) shell was added to SiO(2)-ZnO, with the decreases becoming more significant as the thickness of the titania shell increases. These effects lead to improvements in efficiency for DSSCs that utilize I(-)/I(-)(3), but much larger improvements for DSSCs utilizing ferrocene/ferrocenium, a notoriously fast redox shuttle. For the former, overall energy conversion efficiencies maximize at 4.0%. From a variety of experiments, the primary factor limiting aerogel-based DSSC performance is light loss due to scattering. Nevertheless, variants of the doubly coaxial structure may prove useful in devising DSSCs that can achieve excellent energy conversion efficiencies even with fast redox shuttles.

  20. MO-A-BRD-10: A Fast and Accurate GPU-Based Proton Transport Monte Carlo Simulation for Validating Proton Therapy Treatment Plans

    SciTech Connect

    Wan Chan Tseung, H; Ma, J; Beltran, C

    2014-06-15

    Purpose: To build a GPU-based Monte Carlo (MC) simulation of proton transport with detailed modeling of elastic and non-elastic (NE) protonnucleus interactions, for use in a very fast and cost-effective proton therapy treatment plan verification system. Methods: Using the CUDA framework, we implemented kernels for the following tasks: (1) Simulation of beam spots from our possible scanning nozzle configurations, (2) Proton propagation through CT geometry, taking into account nuclear elastic and multiple scattering, as well as energy straggling, (3) Bertini-style modeling of the intranuclear cascade stage of NE interactions, and (4) Simulation of nuclear evaporation. To validate our MC, we performed: (1) Secondary particle yield calculations in NE collisions with therapeutically-relevant nuclei, (2) Pencil-beam dose calculations in homogeneous phantoms, (3) A large number of treatment plan dose recalculations, and compared with Geant4.9.6p2/TOPAS. A workflow was devised for calculating plans from a commercially available treatment planning system, with scripts for reading DICOM files and generating inputs for our MC. Results: Yields, energy and angular distributions of secondaries from NE collisions on various nuclei are in good agreement with the Geant4.9.6p2 Bertini and Binary cascade models. The 3D-gamma pass rate at 2%–2mm for 70–230 MeV pencil-beam dose distributions in water, soft tissue, bone and Ti phantoms is 100%. The pass rate at 2%–2mm for treatment plan calculations is typically above 98%. The net computational time on a NVIDIA GTX680 card, including all CPU-GPU data transfers, is around 20s for 1×10{sup 7} proton histories. Conclusion: Our GPU-based proton transport MC is the first of its kind to include a detailed nuclear model to handle NE interactions on any nucleus. Dosimetric calculations demonstrate very good agreement with Geant4.9.6p2/TOPAS. Our MC is being integrated into a framework to perform fast routine clinical QA of pencil

  1. A Focused Transport Approach to SEP acceleration at a Fast Parallel Shock in the Corona Including Self-excitation of Alfvén Waves

    NASA Astrophysics Data System (ADS)

    le Roux, J. A.

    2012-12-01

    It has been argued that the acceleration of SEPS at a quasi-parallel CME-driven shock to GeV energies in the corona only occurs if strong wave-excitation by SEPs ahead of the shock reduces the parallel mean free path upstream, thus boosting the rate of diffusive shock acceleration. To investigate this issue, we modeled SEP acceleration at a fast parallel traveling shock in the corona with an existing time-dependent focused transport model. The model has been expanded recently to also feature time-dependent self-excitation and damping of Alfvén waves by SEP anisotropies ahead of the shock based on standard quasi-linear theory. Alfvén wave propagation near the traveling shock is modeled based on standard theory for wave transport in a slowly varying non-uniform plasma medium. Preliminary results will be shown to illustrate the increase in wave power driven by SEP anisotropies upstream, the effect of the shock wave in shortening the wave length and increasing the wave amplitude of Alfvén waves, and the associated acceleration of SEPs by 1st order Fermi acceleration to high energies. The role of the acceleration of the cross-shock solar wind flow, which was found to create a downstream population of shock pre-heated particles which forms an additional source for injection into 1st order Fermi acceleration, will be discussed in terms of how it affects self-excitation of Alfvén waves and the formation of high-energy SEPs by 1st order Fermi acceleration.

  2. Pseudophosphorylation of tau at S422 enhances SDS-stable dimer formation and impairs both anterograde and retrograde fast axonal transport.

    PubMed

    Tiernan, Chelsea T; Combs, Benjamin; Cox, Kristine; Morfini, Gerardo; Brady, Scott T; Counts, Scott E; Kanaan, Nicholas M

    2016-09-01

    In Alzheimer's disease (AD), tau undergoes numerous modifications, including increased phosphorylation at serine-422 (pS422). In the human brain, pS422 tau protein is found in prodromal AD, correlates well with cognitive decline and neuropil thread pathology, and appears associated with increased oligomer formation and exposure of the N-terminal phosphatase-activating domain (PAD). However, whether S422 phosphorylation contributes to toxic mechanisms associated with disease-related forms of tau remains unknown. Here, we report that S422-pseudophosphorylated tau (S422E) lengthens the nucleation phase of aggregation without altering the extent of aggregation or the types of aggregates formed. When compared to unmodified tau aggregates, the S422E modification significantly increased the amount of SDS-stable tau dimers, despite similar levels of immunoreactivity with an oligomer-selective antibody (TOC1) and another antibody that reports PAD exposure (TNT1). Vesicle motility assays in isolated squid axoplasm further revealed that S422E tau monomers inhibited anterograde, kinesin-1 dependent fast axonal transport (FAT). Unexpectedly, and unlike unmodified tau aggregates, which selectively inhibit anterograde FAT, aggregates composed of S422E tau were found to inhibit both anterograde and retrograde FAT. Highlighting the relevance of these findings to human disease, pS422 tau was found to colocalize with tau oligomers and with a fraction of tau showing increased PAD exposure in the human AD brain. This study identifies novel effects of pS422 on tau biochemical properties, including prolonged nucleation and enhanced dimer formation, which correlate with a distinct inhibitory effect on FAT. Taken together, these findings identify a novel mechanistic basis by which pS422 confers upon tau a toxic effect that may directly contribute to axonal dysfunction in AD and other tauopathies. PMID:27373205

  3. Intermodal Transportation: Current Fast Ship Designs Specify Propulsion Systems that Are about 20 Knots Faster than Ships in the Current Fleet

    ERIC Educational Resources Information Center

    Childress, Vincent W.

    2005-01-01

    Intermodal transportation is the moving of people or cargo using more than one mode of transportation. When a person drives to the airport, stands on a conveyor to move through the terminal, and flies to another city, then he or she is using intermodal transportation. Moving cargo in the first half of the twentieth century was a time-consuming and…

  4. Interpretation of fast-ion signals during beam modulation experiments

    NASA Astrophysics Data System (ADS)

    Heidbrink, W. W.; Collins, C. S.; Stagner, L.; Zhu, Y. B.; Petty, C. C.; Van Zeeland, M. A.

    2016-11-01

    Fast-ion signals produced by a modulated neutral beam are used to infer fast-ion transport. The measured quantity is the divergence of perturbed fast-ion flux from the phase-space volume measured by the diagnostic, \

  5. Fast valve

    DOEpatents

    Van Dyke, William J.

    1992-01-01

    A fast valve is disclosed that can close on the order of 7 milliseconds. It is closed by the force of a compressed air spring with the moving parts of the valve designed to be of very light weight and the valve gate being of wedge shaped with O-ring sealed faces to provide sealing contact without metal to metal contact. The combination of the O-ring seal and an air cushion create a soft final movement of the valve closure to prevent the fast air acting valve from having a harsh closing.

  6. Fast valve

    DOEpatents

    Van Dyke, W.J.

    1992-04-07

    A fast valve is disclosed that can close on the order of 7 milliseconds. It is closed by the force of a compressed air spring with the moving parts of the valve designed to be of very light weight and the valve gate being of wedge shaped with O-ring sealed faces to provide sealing contact without metal to metal contact. The combination of the O-ring seal and an air cushion create a soft final movement of the valve closure to prevent the fast air acting valve from having a harsh closing. 4 figs.

  7. Molecular dynamics simulation of the thermodynamic and transport properties of the molten salt fast reactor fuel LiF-ThF4

    NASA Astrophysics Data System (ADS)

    Dewan, Leslie C.; Simon, Christian; Madden, Paul A.; Hobbs, Linn W.; Salanne, Mathieu

    2013-03-01

    The local structure and transport properties of molten LiF-ThF4 at the eutectic composition have been studied at a range of temperatures, using molecular dynamics simulations that incorporate dipole polarization effects. This polarizable interaction potential was parameterized from first-principles calculations. We have calculated the density, self-diffusion coefficients, electrical conductivity, viscosity, and heat capacity at a range of temperatures from 850 K to 1273 K. We have also examined the changes in coordination number as a function of temperature. The simulation results were in good agreement with available experimental data, indicating that such simulations can fulfill a valuable role in augmenting existing experimental work.

  8. Genetic changes during a laboratory adaptive evolution process that allowed fast growth in glucose to an Escherichia coli strain lacking the major glucose transport system

    PubMed Central

    2012-01-01

    Background Escherichia coli strains lacking the phosphoenolpyruvate: carbohydrate phosphotransferase system (PTS), which is the major bacterial component involved in glucose transport and its phosphorylation, accumulate high amounts of phosphoenolpyruvate that can be diverted to the synthesis of commercially relevant products. However, these strains grow slowly in glucose as sole carbon source due to its inefficient transport and metabolism. Strain PB12, with 400% increased growth rate, was isolated after a 120 hours adaptive laboratory evolution process for the selection of faster growing derivatives in glucose. Analysis of the genetic changes that occurred in the PB12 strain that lacks PTS will allow a better understanding of the basis of its growth adaptation and, therefore, in the design of improved metabolic engineering strategies for enhancing carbon diversion into the aromatic pathways. Results Whole genome analyses using two different sequencing methodologies: the Roche NimbleGen Inc. comparative genome sequencing technique, and high throughput sequencing with Illumina Inc. GAIIx, allowed the identification of the genetic changes that occurred in the PB12 strain. Both methods detected 23 non-synonymous and 22 synonymous point mutations. Several non-synonymous mutations mapped in regulatory genes (arcB, barA, rpoD, rna) and in other putative regulatory loci (yjjU, rssA and ypdA). In addition, a chromosomal deletion of 10,328 bp was detected that removed 12 genes, among them, the rppH, mutH and galR genes. Characterization of some of these mutated and deleted genes with their functions and possible functions, are presented. Conclusions The deletion of the contiguous rppH, mutH and galR genes that occurred simultaneously, is apparently the main reason for the faster growth of the evolved PB12 strain. In support of this interpretation is the fact that inactivation of the rppH gene in the parental PB11 strain substantially increased its growth rate, very

  9. Magnetically assisted fast ignition.

    PubMed

    Wang, W-M; Gibbon, P; Sheng, Z-M; Li, Y-T

    2015-01-01

    Fast ignition (FI) is investigated via integrated particle-in-cell simulation including both generation and transport of fast electrons, where petawatt ignition lasers of 2 ps and compressed targets of a peak density of 300  g cm(-3) and areal density of 0.49  g cm(-2) at the core are taken. When a 20 MG static magnetic field is imposed across a conventional cone-free target, the energy coupling from the laser to the core is enhanced by sevenfold and reaches 14%. This value even exceeds that obtained using a cone-inserted target, suggesting that the magnetically assisted scheme may be a viable alternative for FI. With this scheme, it is demonstrated that two counterpropagating, 6 ps, 6 kJ lasers along the magnetic field transfer 12% of their energy to the core, which is then heated to 3 keV. PMID:25615473

  10. Exploiting Resistive Guiding for Fast Ignition

    NASA Astrophysics Data System (ADS)

    Robinson, Alex

    2012-10-01

    Devising methods and schemes for controlling fast electron transport remains a major challenge in Fast Ignition research. Realistic estimates of the fast electron divergence angle require this control in order to ensure that the fast electron to hot spot coupling efficiency does not reach excessively low values. Resistivity gradients in the target will lead to strong magnetic field growth (via ∇ηxj) which can be exploited for the purposes of controlling the fast electron propagation (Robinson and Sherlock, PoP (2007)). There are a number of possible schemes which might be considered. Here we will report on numerical simulations that we have carried out on both simple configurations such as parabolic reflectors, and complex arrangements (Robinson, Key and Tabak, PRL (2012)). Substantial improvements to the fast electron to hot spot coupling efficiency have been found even for realistic fast electron divergence angles.

  11. Physical studies of fast ignition in China

    NASA Astrophysics Data System (ADS)

    He, X. T.; Cai, Hong-bo; Wu, Si-zhong; Cao, Li-hua; Zhang, Hua; He, Ming-qing; Chen, Mo; Wu, Jun-feng; Zhou, Cang-tao; Zhou, Wei-Min; Shan, Lian-qiang; Wang, Wei-wu; Zhang, Feng; Bi, Bi; Zhao, Zong-qing; Gu, Yu-qiu; Zhang, Bao-han; Wang, Wei; Fang, Zhi-heng; Lei, An-le; Wang, Chen; Pei, Wen-bing; Fu, Si-zu

    2015-06-01

    Fast ignition approach to inertial confinement fusion is one of the important goals today, in addition to central hot spot ignition in China. The SG-IIU and PW laser facilities are coupled to investigate the hot spot formation for fast ignition. The SG-III laser facility is almost completed and will be coupled with tens kJ PW lasers for the demonstration of fast ignition. In recent years, for physical studies of fast ignition, we have been focusing on the experimental study of implosion symmetry, M-band radiation preheating and mixing, advanced fast ignition target design, and so on. In addition, the modeling capabilities and code developments enhanced our ability to perform the hydro-simulation of the compression implosion, and the particle-in-cell (PIC) and hybrid-PIC simulation of the generation, transport and deposition of relativistic electron beams. Considerable progress has been achieved in understanding the critical issues of fast ignition.

  12. FAST: FAST Analysis of Sequences Toolbox

    PubMed Central

    Lawrence, Travis J.; Kauffman, Kyle T.; Amrine, Katherine C. H.; Carper, Dana L.; Lee, Raymond S.; Becich, Peter J.; Canales, Claudia J.; Ardell, David H.

    2015-01-01

    FAST (FAST Analysis of Sequences Toolbox) provides simple, powerful open source command-line tools to filter, transform, annotate and analyze biological sequence data. Modeled after the GNU (GNU's Not Unix) Textutils such as grep, cut, and tr, FAST tools such as fasgrep, fascut, and fastr make it easy to rapidly prototype expressive bioinformatic workflows in a compact and generic command vocabulary. Compact combinatorial encoding of data workflows with FAST commands can simplify the documentation and reproducibility of bioinformatic protocols, supporting better transparency in biological data science. Interface self-consistency and conformity with conventions of GNU, Matlab, Perl, BioPerl, R, and GenBank help make FAST easy and rewarding to learn. FAST automates numerical, taxonomic, and text-based sorting, selection and transformation of sequence records and alignment sites based on content, index ranges, descriptive tags, annotated features, and in-line calculated analytics, including composition and codon usage. Automated content- and feature-based extraction of sites and support for molecular population genetic statistics make FAST useful for molecular evolutionary analysis. FAST is portable, easy to install and secure thanks to the relative maturity of its Perl and BioPerl foundations, with stable releases posted to CPAN. Development as well as a publicly accessible Cookbook and Wiki are available on the FAST GitHub repository at https://github.com/tlawrence3/FAST. The default data exchange format in FAST is Multi-FastA (specifically, a restriction of BioPerl FastA format). Sanger and Illumina 1.8+ FastQ formatted files are also supported. FAST makes it easier for non-programmer biologists to interactively investigate and control biological data at the speed of thought. PMID:26042145

  13. FAST: FAST Analysis of Sequences Toolbox.

    PubMed

    Lawrence, Travis J; Kauffman, Kyle T; Amrine, Katherine C H; Carper, Dana L; Lee, Raymond S; Becich, Peter J; Canales, Claudia J; Ardell, David H

    2015-01-01

    FAST (FAST Analysis of Sequences Toolbox) provides simple, powerful open source command-line tools to filter, transform, annotate and analyze biological sequence data. Modeled after the GNU (GNU's Not Unix) Textutils such as grep, cut, and tr, FAST tools such as fasgrep, fascut, and fastr make it easy to rapidly prototype expressive bioinformatic workflows in a compact and generic command vocabulary. Compact combinatorial encoding of data workflows with FAST commands can simplify the documentation and reproducibility of bioinformatic protocols, supporting better transparency in biological data science. Interface self-consistency and conformity with conventions of GNU, Matlab, Perl, BioPerl, R, and GenBank help make FAST easy and rewarding to learn. FAST automates numerical, taxonomic, and text-based sorting, selection and transformation of sequence records and alignment sites based on content, index ranges, descriptive tags, annotated features, and in-line calculated analytics, including composition and codon usage. Automated content- and feature-based extraction of sites and support for molecular population genetic statistics make FAST useful for molecular evolutionary analysis. FAST is portable, easy to install and secure thanks to the relative maturity of its Perl and BioPerl foundations, with stable releases posted to CPAN. Development as well as a publicly accessible Cookbook and Wiki are available on the FAST GitHub repository at https://github.com/tlawrence3/FAST. The default data exchange format in FAST is Multi-FastA (specifically, a restriction of BioPerl FastA format). Sanger and Illumina 1.8+ FastQ formatted files are also supported. FAST makes it easier for non-programmer biologists to interactively investigate and control biological data at the speed of thought.

  14. Enhanced Model for Fast Ignition

    SciTech Connect

    Mason, Rodney J.

    2010-10-12

    Laser Fusion is a prime candidate for alternate energy production, capable of serving a major portion of the nation's energy needs, once fusion fuel can be readily ignited. Fast Ignition may well speed achievement of this goal, by reducing net demands on laser pulse energy and timing precision. However, Fast Ignition has presented a major challenge to modeling. This project has enhanced the computer code ePLAS for the simulation of the many specialized phenomena, which arise with Fast Ignition. The improved code has helped researchers to understand better the consequences of laser absorption, energy transport, and laser target hydrodynamics. ePLAS uses efficient implicit methods to acquire solutions for the electromagnetic fields that govern the accelerations of electrons and ions in targets. In many cases, the code implements fluid modeling for these components. These combined features, "implicitness and fluid modeling," can greatly facilitate calculations, permitting the rapid scoping and evaluation of experiments. ePLAS can be used on PCs, Macs and Linux machines, providing researchers and students with rapid results. This project has improved the treatment of electromagnetics, hydrodynamics, and atomic physics in the code. It has simplified output graphics, and provided new input that avoids the need for source code access by users. The improved code can now aid university, business and national laboratory users in pursuit of an early path to success with Fast Ignition.

  15. Fast superconducting magnetic field switch

    SciTech Connect

    Goren, Y.; Mahale, N.K.

    1995-12-31

    The superconducting magnetic switch or fast kicker magnet is employed with an electron stream or a bunch of electrons to rapidly change the direction of flow of the electron stream or bunch of electrons. The apparatus employs a beam tube which is coated with a film of superconducting material. The tube is cooled to a temperature below the superconducting transition temperature and is subjected to a constant magnetic field which is produced by an external dc magnet. The magnetic field produced by the dc magnet is less than the critical field for the superconducting material, thus, creating a Meissner Effect condition. A controllable fast electromagnet is used to provide a magnetic field which supplements that of the dc magnet so that when the fast magnet is energized the combined magnetic field is now greater than the critical field and the superconducting material returns to its normal state allowing the magnetic field to penetrate the tube. This produces an internal field which effects the direction of motion and of the electron stream or electron bunch. The switch can also operate as a switching mechanism for charged particles. Magnetic switches and particularly fast kicker magnets are used in the accelerator industry to quickly deflect particle beams into and out of various transport lines, storage rings, dumps, and specifically to differentially route individual bunches of particles from a train of bunches which are injected or ejected from a given ring.

  16. Catalytic fast pyrolysis of lignocellulosic biomass

    SciTech Connect

    Liu, Changjun; Wang, Huamin; Karim, Ayman M.; Sun, Junming; Wang, Yong

    2014-11-21

    Increasing energy demand, especially in the transportation sector, and soaring CO2 emissions necessitate the exploitation of renewable sources of energy. Despite the large variety of new energy Q3 carriers, liquid hydrocarbon still appears to be the most attractive and feasible form of transportation fuel taking into account the energy density, stability and existing infrastructure. Biomass is an abundant, renewable source of energy; however, utilizing it in a cost-effective way is still a substantial challenge. Lignocellulose is composed of three major biopolymers, namely cellulose, hemicellulose and lignin. Fast pyrolysis of biomass is recognized as an efficient and feasible process to selectively convert lignocellulose into a liquid fuel—bio-oil. However bio-oil from fast pyrolysis contains a large amount of oxygen, distributed in hundreds of oxygenates. These oxygenates are the cause of many negative properties, such as low heating values, high corrosiveness, high viscosity, and instability; they also greatly Q4 limit the application of bio-oil particularly as transportation fuel. Hydrocarbons derived from biomass are most attractive because of their high energy density and compatibility with the existing infrastructure. Thus, converting lignocellulose into transportation fuels via catalytic fast pyrolysis has attracted much attention. Many studies related to catalytic fast pyrolysis of biomass have been published. The main challenge of this process is the development of active and stable catalysts that can deal with a large variety of decomposition intermediates from lignocellulose. This review starts with the current understanding of the chemistry in fast pyrolysis of lignocellulose and focuses on the development of catalysts in catalytic fast pyrolysis. Recent progress in the experimental studies on catalytic fast pyrolysis of biomass is also summarized with the emphasis on bio-oil yields and quality.

  17. Catalytic fast pyrolysis of lignocellulosic biomass.

    PubMed

    Liu, Changjun; Wang, Huamin; Karim, Ayman M; Sun, Junming; Wang, Yong

    2014-11-21

    Increasing energy demand, especially in the transportation sector, and soaring CO2 emissions necessitate the exploitation of renewable sources of energy. Despite the large variety of new energy carriers, liquid hydrocarbon still appears to be the most attractive and feasible form of transportation fuel taking into account the energy density, stability and existing infrastructure. Biomass is an abundant, renewable source of energy; however, utilizing it in a cost-effective way is still a substantial challenge. Lignocellulose is composed of three major biopolymers, namely cellulose, hemicellulose and lignin. Fast pyrolysis of biomass is recognized as an efficient and feasible process to selectively convert lignocellulose into a liquid fuel-bio-oil. However bio-oil from fast pyrolysis contains a large amount of oxygen, distributed in hundreds of oxygenates. These oxygenates are the cause of many negative properties, such as low heating value, high corrosiveness, high viscosity, and instability; they also greatly limit the application of bio-oil particularly as transportation fuel. Hydrocarbons derived from biomass are most attractive because of their high energy density and compatibility with the existing infrastructure. Thus, converting lignocellulose into transportation fuels via catalytic fast pyrolysis has attracted much attention. Many studies related to catalytic fast pyrolysis of biomass have been published. The main challenge of this process is the development of active and stable catalysts that can deal with a large variety of decomposition intermediates from lignocellulose. This review starts with the current understanding of the chemistry in fast pyrolysis of lignocellulose and focuses on the development of catalysts in catalytic fast pyrolysis. Recent progress in the experimental studies on catalytic fast pyrolysis of biomass is also summarized with the emphasis on bio-oil yields and quality.

  18. Catalytic fast pyrolysis of lignocellulosic biomass.

    PubMed

    Liu, Changjun; Wang, Huamin; Karim, Ayman M; Sun, Junming; Wang, Yong

    2014-11-21

    Increasing energy demand, especially in the transportation sector, and soaring CO2 emissions necessitate the exploitation of renewable sources of energy. Despite the large variety of new energy carriers, liquid hydrocarbon still appears to be the most attractive and feasible form of transportation fuel taking into account the energy density, stability and existing infrastructure. Biomass is an abundant, renewable source of energy; however, utilizing it in a cost-effective way is still a substantial challenge. Lignocellulose is composed of three major biopolymers, namely cellulose, hemicellulose and lignin. Fast pyrolysis of biomass is recognized as an efficient and feasible process to selectively convert lignocellulose into a liquid fuel-bio-oil. However bio-oil from fast pyrolysis contains a large amount of oxygen, distributed in hundreds of oxygenates. These oxygenates are the cause of many negative properties, such as low heating value, high corrosiveness, high viscosity, and instability; they also greatly limit the application of bio-oil particularly as transportation fuel. Hydrocarbons derived from biomass are most attractive because of their high energy density and compatibility with the existing infrastructure. Thus, converting lignocellulose into transportation fuels via catalytic fast pyrolysis has attracted much attention. Many studies related to catalytic fast pyrolysis of biomass have been published. The main challenge of this process is the development of active and stable catalysts that can deal with a large variety of decomposition intermediates from lignocellulose. This review starts with the current understanding of the chemistry in fast pyrolysis of lignocellulose and focuses on the development of catalysts in catalytic fast pyrolysis. Recent progress in the experimental studies on catalytic fast pyrolysis of biomass is also summarized with the emphasis on bio-oil yields and quality. PMID:24801125

  19. Electron Beams for Fast Ignition

    NASA Astrophysics Data System (ADS)

    Fonseca, R. A.; Davies, J. R.; Silva, L. O.

    2004-11-01

    In the fast ignitor scenario an intense relativistic electron beam is used to deposit energy inside the fuel target and trigger the thermonuclear reaction. This electron beam is produced on the outer plasma layer of the target by the interaction of an ultra-intense laser. The energy transfer from the laser to the electron beam, and the stability of the propagation of the electron beam are crucial for a successful fast ignitor scheme. We have used three-dimensional particle-in-cell simulations using the OSIRIS.framework [1] to explore the self-consistent generation of high current electron beams by ultra intense lasers. Novel laser pulse configurations are explored in order to generate electron beams transporting more energy, and capable of avoiding the deleterious effects of collisionless instabilities in the plasma corona. [1] R. A. Fonseca et al., LNCS 2331, 342-351, (Springer, Heidelberg, 2002);

  20. Fast food tips (image)

    MedlinePlus

    ... challenge to eat healthy when going to a fast food place. In general, avoiding items that are deep ... challenge to eat healthy when going to a fast food place. In general, avoiding items that are deep ...

  1. Fast food (image)

    MedlinePlus

    Fast foods are quick, reasonably priced, and readily available alternatives to home cooking. While convenient and economical for a busy lifestyle, fast foods are typically high in calories, fat, saturated fat, ...

  2. Is fast food addictive?

    PubMed

    Garber, Andrea K; Lustig, Robert H

    2011-09-01

    Studies of food addiction have focused on highly palatable foods. While fast food falls squarely into that category, it has several other attributes that may increase its salience. This review examines whether the nutrients present in fast food, the characteristics of fast food consumers or the presentation and packaging of fast food may encourage substance dependence, as defined by the American Psychiatric Association. The majority of fast food meals are accompanied by a soda, which increases the sugar content 10-fold. Sugar addiction, including tolerance and withdrawal, has been demonstrated in rodents but not humans. Caffeine is a "model" substance of dependence; coffee drinks are driving the recent increase in fast food sales. Limited evidence suggests that the high fat and salt content of fast food may increase addictive potential. Fast food restaurants cluster in poorer neighborhoods and obese adults eat more fast food than those who are normal weight. Obesity is characterized by resistance to insulin, leptin and other hormonal signals that would normally control appetite and limit reward. Neuroimaging studies in obese subjects provide evidence of altered reward and tolerance. Once obese, many individuals meet criteria for psychological dependence. Stress and dieting may sensitize an individual to reward. Finally, fast food advertisements, restaurants and menus all provide environmental cues that may trigger addictive overeating. While the concept of fast food addiction remains to be proven, these findings support the role of fast food as a potentially addictive substance that is most likely to create dependence in vulnerable populations.

  3. Is fast food addictive?

    PubMed

    Garber, Andrea K; Lustig, Robert H

    2011-09-01

    Studies of food addiction have focused on highly palatable foods. While fast food falls squarely into that category, it has several other attributes that may increase its salience. This review examines whether the nutrients present in fast food, the characteristics of fast food consumers or the presentation and packaging of fast food may encourage substance dependence, as defined by the American Psychiatric Association. The majority of fast food meals are accompanied by a soda, which increases the sugar content 10-fold. Sugar addiction, including tolerance and withdrawal, has been demonstrated in rodents but not humans. Caffeine is a "model" substance of dependence; coffee drinks are driving the recent increase in fast food sales. Limited evidence suggests that the high fat and salt content of fast food may increase addictive potential. Fast food restaurants cluster in poorer neighborhoods and obese adults eat more fast food than those who are normal weight. Obesity is characterized by resistance to insulin, leptin and other hormonal signals that would normally control appetite and limit reward. Neuroimaging studies in obese subjects provide evidence of altered reward and tolerance. Once obese, many individuals meet criteria for psychological dependence. Stress and dieting may sensitize an individual to reward. Finally, fast food advertisements, restaurants and menus all provide environmental cues that may trigger addictive overeating. While the concept of fast food addiction remains to be proven, these findings support the role of fast food as a potentially addictive substance that is most likely to create dependence in vulnerable populations. PMID:21999689

  4. Fast food: friendly?

    PubMed

    Rice, S; McAllister, E J; Dhurandhar, N V

    2007-06-01

    Fast food is routinely blamed for the obesity epidemic and consequentially excluded from professional dietary recommendations. However, several sections of society including senior citizens, low-income adult and children, minority and homeless children, or those pressed for time appear to rely on fast food as an important source of meals. Considering the dependence of these nutritionally vulnerable population groups on fast food, we examined the possibility of imaginative selection of fast food, which would attenuate the potentially unfavorable nutrient composition. We present a sample menu to demonstrate that it is possible to design a fast food menu that provides reasonable level of essential nutrients without exceeding the caloric recommendations. We would like to alert health-care professionals that fast food need not be forbidden under all circumstances, and that a fresh look at the role of fast food may enable its inclusion in meal planning for those who depend on it out of necessity, while adding flexibility.

  5. FAST User Guide

    NASA Technical Reports Server (NTRS)

    Walatka, Pamela P.; Clucas, Jean; McCabe, R. Kevin; Plessel, Todd; Potter, R.; Cooper, D. M. (Technical Monitor)

    1994-01-01

    The Flow Analysis Software Toolkit, FAST, is a software environment for visualizing data. FAST is a collection of separate programs (modules) that run simultaneously and allow the user to examine the results of numerical and experimental simulations. The user can load data files, perform calculations on the data, visualize the results of these calculations, construct scenes of 3D graphical objects, and plot, animate and record the scenes. Computational Fluid Dynamics (CFD) visualization is the primary intended use of FAST, but FAST can also assist in the analysis of other types of data. FAST combines the capabilities of such programs as PLOT3D, RIP, SURF, and GAS into one environment with modules that share data. Sharing data between modules eliminates the drudgery of transferring data between programs. All the modules in the FAST environment have a consistent, highly interactive graphical user interface. Most commands are entered by pointing and'clicking. The modular construction of FAST makes it flexible and extensible. The environment can be custom configured and new modules can be developed and added as needed. The following modules have been developed for FAST: VIEWER, FILE IO, CALCULATOR, SURFER, TOPOLOGY, PLOTTER, TITLER, TRACER, ARCGRAPH, GQ, SURFERU, SHOTET, and ISOLEVU. A utility is also included to make the inclusion of user defined modules in the FAST environment easy. The VIEWER module is the central control for the FAST environment. From VIEWER, the user can-change object attributes, interactively position objects in three-dimensional space, define and save scenes, create animations, spawn new FAST modules, add additional view windows, and save and execute command scripts. The FAST User Guide uses text and FAST MAPS (graphical representations of the entire user interface) to guide the user through the use of FAST. Chapters include: Maps, Overview, Tips, Getting Started Tutorial, a separate chapter for each module, file formats, and system

  6. Measuring Fast Ion Losses in a Reversed Field Pinch Plasma

    NASA Astrophysics Data System (ADS)

    Bonofiglo, P. J.; Anderson, J. K.; Almagri, A. F.; Kim, J.; Clark, J.; Capecchi, W.; Sears, S. H.

    2015-11-01

    The reversed field pinch (RFP) provides a unique environment to study fast ion confinement and transport. The RFP's weak toroidal field, strong magnetic shear, and ability to enter a 3D state provide a wide range of dynamics to study fast ions. Core-localized, 25 keV fast ions are sourced into MST by a tangentially injected hydrogen/deuterium neutral beam. Neutral particle analysis and measured fusion neutron flux indicate enhanced fast ion transport in the plasma core. Past experiments point to a dynamic loss of fast ions associated with the RFP's transition to a 3D state and with beam-driven, bursting magnetic modes. Consequently, fast ion transport and losses in the RFP have garnered recent attention. Valuable information on fast-ion loss, such as energy and pitch distributions, are sought to provide a better understanding of the transport mechanisms at hand. We have constructed and implemented two fast ion loss detectors (FILDs) for use on MST. The FILDs have two, independent, design concepts: collecting particles as a function of v⊥ or with pitch greater than 0.8. In this work, we present our preliminary findings and results from our FILDs on MST. This research is supported by US DOE.

  7. Fast Ion Redistribution and Implications for the Hybrid Regime

    SciTech Connect

    Nazikian, R; Austin, M E; Budny, R V; Chu, M S; Heidbrink, W W; Makowski, M A; Petty, C C; Politzer, P A; Solomon, W M; Van Zeeland, M A

    2007-06-26

    Time dependent TRANSP analysis indicates that radial redistribution of fast ions is unlikely to affect the central current density in hybrid plasmas sufficient to raise q(0) above unity. The results suggest that some other mechanism other than fast ion transport must be involved in raising q(0) and preventing sawteeth in hybrid plasmas.

  8. Diagnostics for Fast Ignition Science

    SciTech Connect

    MacPhee, A; Akli, K; Beg, F; Chen, C; Chen, H; Clarke, R; Hey, D; Freeman, R; Kemp, A; Key, M; King, J; LePape, S; Link, A; Ma, T; Nakamura, N; Offermann, D; Ovchinnikov, V; Patel, P; Phillips, T; Stephens, R; Town, R; Wei, M; VanWoerkom, L; Mackinnon, A

    2008-05-06

    The concept for Electron Fast Ignition Inertial Confinement Fusion demands sufficient laser energy be transferred from the ignitor pulse to the assembled fuel core via {approx}MeV electrons. We have assembled a suite of diagnostics to characterize such transfer. Recent experiments have simultaneously fielded absolutely calibrated extreme ultraviolet multilayer imagers at 68 and 256eV; spherically bent crystal imagers at 4 and 8keV; multi-keV crystal spectrometers; MeV x-ray bremmstrahlung and electron and proton spectrometers (along the same line of sight); nuclear activation samples and a picosecond optical probe based interferometer. These diagnostics allow careful measurement of energy transport and deposition during and following laser-plasma interactions at extremely high intensities in both planar and conical targets. Augmented with accurate on-shot laser focal spot and pre-pulse characterization, these measurements are yielding new insight into energy coupling and are providing critical data for validating numerical PIC and hybrid PIC simulation codes in an area that is crucial for many applications, particularly fast ignition. Novel aspects of these diagnostics and how they are combined to extract quantitative data on ultra high intensity laser plasma interactions are discussed, together with implications for full-scale fast ignition experiments.

  9. fast-matmul

    SciTech Connect

    Grey Ballard, Austin Benson

    2014-11-26

    This software provides implementations of fast matrix multiplication algorithms. These algorithms perform fewer floating point operations than the classical cubic algorithm. The software uses code generation to automatically implement the fast algorithms based on high-level descriptions. The code serves two general purposes. The first is to demonstrate that these fast algorithms can out-perform vendor matrix multiplication algorithms for modest problem sizes on a single machine. The second is to rapidly prototype many variations of fast matrix multiplication algorithms to encourage future research in this area. The implementations target sequential and shared memory parallel execution.

  10. Fast robust correlation.

    PubMed

    Fitch, Alistair J; Kadyrov, Alexander; Christmas, William J; Kittler, Josef

    2005-08-01

    A new, fast, statistically robust, exhaustive, translational image-matching technique is presented: fast robust correlation. Existing methods are either slow or non-robust, or rely on optimization. Fast robust correlation works by expressing a robust matching surface as a series of correlations. Speed is obtained by computing correlations in the frequency domain. Computational cost is analyzed and the method is shown to be fast. Speed is comparable to conventional correlation and, for large images, thousands of times faster than direct robust matching. Three experiments demonstrate the advantage of the technique over standard correlation.

  11. [Medical aspects of fasting].

    PubMed

    Gavrankapetanović, F

    1997-01-01

    Fasting (arabic-savm) was proclaimed through islam, and thus it is an obligation for Holly Prophet Muhammad s.a.v.s.-Peace be to Him-in the second year after Hijra (in 624 after Milad-born of Isa a.s.). There is a month of fasting-Ramadan-each lunar (hijra) year. So, it was 1415th fasting this year. Former Prophets have brought obligative messages on fasting to their people; so there are also certain forms of fasting with other religions i.e. with Catholics, Jews, Orthodox. These kinds of fasting above differ from muslim fasting, but they also appear obligative. All revelations have brought fasting as obligative. From medical point of view, fasting has two basical components: psychical and physical. Psychical sphere correlate closely with its fundamental ideological message. Allah dz.s. says in Quran: "... Fasting is obligative for you, as it was obligative to your precedents, as to avoid sins; during very few days (II, II, 183 & 184)." Will strength, control of passions, effort and self-discipline makes a pure faithfull person, who purify its mind and body through fasting. Thinking about The Creator is more intensive, character is more solid; and spirit and will get stronger. We will mention the hadith saying: "Essaihune humus saimun!" That means: "Travellers at the Earth are fasters (of my ummet)." The commentary of this hadith, in the Collection of 1001 hadiths (Bin bir hadis), number 485, says: "There are no travelling dervishs or monks in islam; thus there is no such a kind of relligousity in islam. In stead, it is changed by fasting and constant attending of mosque. That was proclaimed as obligation, although there were few cases of travelling in the name of relligousity, like travelling dervishs and sheichs." In this paper, the author discusses medical aspects of fasting and its positive characteristics in the respect of healthy life style and prevention of many sicks. The author mentions positive influence of fasting to certain system and organs of human

  12. Integrative Physiology of Fasting.

    PubMed

    Secor, Stephen M; Carey, Hannah V

    2016-04-01

    Extended bouts of fasting are ingrained in the ecology of many organisms, characterizing aspects of reproduction, development, hibernation, estivation, migration, and infrequent feeding habits. The challenge of long fasting episodes is the need to maintain physiological homeostasis while relying solely on endogenous resources. To meet that challenge, animals utilize an integrated repertoire of behavioral, physiological, and biochemical responses that reduce metabolic rates, maintain tissue structure and function, and thus enhance survival. We have synthesized in this review the integrative physiological, morphological, and biochemical responses, and their stages, that characterize natural fasting bouts. Underlying the capacity to survive extended fasts are behaviors and mechanisms that reduce metabolic expenditure and shift the dependency to lipid utilization. Hormonal regulation and immune capacity are altered by fasting; hormones that trigger digestion, elevate metabolism, and support immune performance become depressed, whereas hormones that enhance the utilization of endogenous substrates are elevated. The negative energy budget that accompanies fasting leads to the loss of body mass as fat stores are depleted and tissues undergo atrophy (i.e., loss of mass). Absolute rates of body mass loss scale allometrically among vertebrates. Tissues and organs vary in the degree of atrophy and downregulation of function, depending on the degree to which they are used during the fast. Fasting affects the population dynamics and activities of the gut microbiota, an interplay that impacts the host's fasting biology. Fasting-induced gene expression programs underlie the broad spectrum of integrated physiological mechanisms responsible for an animal's ability to survive long episodes of natural fasting. PMID:27065168

  13. Fast protein folding kinetics

    PubMed Central

    Gelman, Hannah; Gruebele, Martin

    2014-01-01

    Fast folding proteins have been a major focus of computational and experimental study because they are accessible to both techniques: they are small and fast enough to be reasonably simulated with current computational power, but have dynamics slow enough to be observed with specially developed experimental techniques. This coupled study of fast folding proteins has provided insight into the mechanisms which allow some proteins to find their native conformation well less than 1 ms and has uncovered examples of theoretically predicted phenomena such as downhill folding. The study of fast folders also informs our understanding of even “slow” folding processes: fast folders are small, relatively simple protein domains and the principles that govern their folding also govern the folding of more complex systems. This review summarizes the major theoretical and experimental techniques used to study fast folding proteins and provides an overview of the major findings of fast folding research. Finally, we examine the themes that have emerged from studying fast folders and briefly summarize their application to protein folding in general as well as some work that is left to do. PMID:24641816

  14. fastKDE

    SciTech Connect

    O'Brien, Travis A.; Kashinath, Karthik

    2015-05-22

    This software implements the fast, self-consistent probability density estimation described by O'Brien et al. (2014, doi: ). It uses a non-uniform fast Fourier transform technique to reduce the computational cost of an objective and self-consistent kernel density estimation method.

  15. Fast and effective?

    PubMed

    Trueland, Jennifer

    2013-12-18

    The 5.2 diet involves two days of fasting each week. It is being promoted as the key to sustained weight loss, as well as wider health benefits, despite the lack of evidence on the long-term effects. Nurses need to support patients who wish to try intermittent fasting. PMID:24345130

  16. A Code to Produce Cell Averaged Cross Sections for Fast Critical Assemblies and Fast Power Reactors.

    1987-05-14

    Version 00 SLAROM solves the neutron integral transport equations to determine the flux distribution and spectra in a fast reactor lattice and calculates cell averaged effective cross sections. The code uses multigroup data of the type in DLC-111/JFS that use Bondarenko factors for resonance effects.

  17. Investigation of the fast ion beta limit in MST

    NASA Astrophysics Data System (ADS)

    Capecchi, William; Eilerman, Scott; Reusch, Joshua; Koliner, Jonathan; Anderson, Jay; Lin, Liang; Clark, Jerry; Liu, Deyong

    2013-10-01

    Fast ion orbits in the reversed field pinch (RFP) magnetic configuration are well ordered and have low orbit loss, even considering the stochasticity of the magnetic field generated by multiple tearing modes. Purely classical TRANSP modeling of a 1MW tangentially injected hydrogen neutral beam in MST deuterium plasmas predicts a core-localized fast ion density that can be up to 25% of the electron density and a fast ion beta of many times the local thermal beta. However, neutral particle analysis (NPA) of an NBI-driven mode (presumably driven by a fast ion pressure gradient) clearly shows transport of core-localized fast ions and a saturated fast ion density. The TRANSP modeling is presumed valid until the onset of the beam driven mode and gives an initial estimate of the volume-averaged fast ion beta in the range of 1-2% (local core value up to 10%). Distinguishing between an experimental fast ion number limit or fast ion beta limit is performed by scanning both the magnetic field strength and the NBI energy while observing conditions at the onset of the beam driven mode. Upcoming experiments will further investigate the empirical fast ion beta limit through the use of a deuterium beam into deuterium plasma which will allow for the NPA and neutron flux signals to provide a local and global fast ion beta measurement respectively. Work supported by US DoE.

  18. Reusable fast opening switch

    DOEpatents

    Van Devender, John P.; Emin, David

    1986-01-01

    A reusable fast opening switch for transferring energy, in the form of a high power pulse, from an electromagnetic storage device such as an inductor into a load. The switch is efficient, compact, fast and reusable. The switch comprises a ferromagnetic semiconductor which undergoes a fast transition between conductive and insulating states at a critical temperature and which undergoes the transition without a phase change in its crystal structure. A semiconductor such as europium rich europhous oxide, which undergoes a conductor to insulator transition when it is joule heated from its conductor state, can be used to form the switch.

  19. Reusable fast opening switch

    DOEpatents

    Van Devender, J.P.; Emin, D.

    1983-12-21

    A reusable fast opening switch for transferring energy, in the form of a high power pulse, from an electromagnetic storage device such as an inductor into a load. The switch is efficient, compact, fast and reusable. The switch comprises a ferromagnetic semiconductor which undergoes a fast transition between conductive and metallic states at a critical temperature and which undergoes the transition without a phase change in its crystal structure. A semiconductor such as europium rich europhous oxide, which undergoes a conductor to insulator transition when it is joule heated from its conductor state, can be used to form the switch.

  20. fast-matmul

    2014-11-26

    This software provides implementations of fast matrix multiplication algorithms. These algorithms perform fewer floating point operations than the classical cubic algorithm. The software uses code generation to automatically implement the fast algorithms based on high-level descriptions. The code serves two general purposes. The first is to demonstrate that these fast algorithms can out-perform vendor matrix multiplication algorithms for modest problem sizes on a single machine. The second is to rapidly prototype many variations of fastmore » matrix multiplication algorithms to encourage future research in this area. The implementations target sequential and shared memory parallel execution.« less

  1. Fast Breeder Reactor studies

    SciTech Connect

    Till, C.E.; Chang, Y.I.; Kittel, J.H.; Fauske, H.K.; Lineberry, M.J.; Stevenson, M.G.; Amundson, P.I.; Dance, K.D.

    1980-07-01

    This report is a compilation of Fast Breeder Reactor (FBR) resource documents prepared to provide the technical basis for the US contribution to the International Nuclear Fuel Cycle Evaluation. The eight separate parts deal with the alternative fast breeder reactor fuel cycles in terms of energy demand, resource base, technical potential and current status, safety, proliferation resistance, deployment, and nuclear safeguards. An Annex compares the cost of decommissioning light-water and fast breeder reactors. Separate abstracts are included for each of the parts.

  2. Fast-ion D{alpha} measurements of the fast-ion distribution (invited)

    SciTech Connect

    Heidbrink, W. W.

    2010-10-15

    The fast-ion D{alpha} (FIDA) diagnostic is an application of charge-exchange recombination spectroscopy. Fast ions that neutralize in an injected neutral beam emit Balmer-{alpha} light with a large Doppler shift. The spectral shift is exploited to distinguish the FIDA emission from other bright sources of D{alpha} light. Background subtraction is the main technical challenge. A spectroscopic diagnostic typically achieves temporal, energy, and transverse spatial resolution of {approx}1 ms, {approx}10 keV, and {approx}2 cm, respectively. Installations that use narrow-band filters achieve high spatial and temporal resolution at the expense of spectral information. For high temporal resolution, the bandpass-filtered light goes directly to a photomultiplier, allowing detection of {approx}50 kHz oscillations in FIDA signal. For two-dimensional spatial profiles, the bandpass-filtered light goes to a charge-coupled device camera; detailed images of fast-ion redistribution at instabilities are obtained. Qualitative and quantitative models relate the measured FIDA signals to the fast-ion distribution function. The first quantitative comparisons between theory and experiment found excellent agreement in beam-heated magnetohydrodynamics (MHD)-quiescent plasmas. FIDA diagnostics are now in operation at magnetic-fusion facilities worldwide. They are used to study fast-ion acceleration by ion cyclotron heating, to detect fast-ion transport by MHD modes and microturbulence, and to study fast-ion driven instabilities.

  3. Fast-ion Dα measurements of the fast-ion distribution (invited).

    PubMed

    Heidbrink, W W

    2010-10-01

    The fast-ion Dα (FIDA) diagnostic is an application of charge-exchange recombination spectroscopy. Fast ions that neutralize in an injected neutral beam emit Balmer-α light with a large Doppler shift. The spectral shift is exploited to distinguish the FIDA emission from other bright sources of Dα light. Background subtraction is the main technical challenge. A spectroscopic diagnostic typically achieves temporal, energy, and transverse spatial resolution of ∼1 ms, ∼10 keV, and ∼2 cm, respectively. Installations that use narrow-band filters achieve high spatial and temporal resolution at the expense of spectral information. For high temporal resolution, the bandpass-filtered light goes directly to a photomultiplier, allowing detection of ∼50 kHz oscillations in FIDA signal. For two-dimensional spatial profiles, the bandpass-filtered light goes to a charge-coupled device camera; detailed images of fast-ion redistribution at instabilities are obtained. Qualitative and quantitative models relate the measured FIDA signals to the fast-ion distribution function. The first quantitative comparisons between theory and experiment found excellent agreement in beam-heated magnetohydrodynamics (MHD)-quiescent plasmas. FIDA diagnostics are now in operation at magnetic-fusion facilities worldwide. They are used to study fast-ion acceleration by ion cyclotron heating, to detect fast-ion transport by MHD modes and microturbulence, and to study fast-ion driven instabilities.

  4. Discovery with FAST

    NASA Astrophysics Data System (ADS)

    Wilkinson, P.

    2016-02-01

    FAST offers "transformational" performance well-suited to finding new phenomena - one of which might be polarised spectral transients. But discoveries will only be made if "the system" provides its users with the necessary opportunities. In addition to designing in as much observational flexibility as possible, FAST should be operated with a philosophy which maximises its "human bandwidth". This band includes the astronomers of tomorrow - many of whom not have yet started school or even been born.

  5. A Fast Hermite Transform★

    PubMed Central

    Leibon, Gregory; Rockmore, Daniel N.; Park, Wooram; Taintor, Robert; Chirikjian, Gregory S.

    2008-01-01

    We present algorithms for fast and stable approximation of the Hermite transform of a compactly supported function on the real line, attainable via an application of a fast algebraic algorithm for computing sums associated with a three-term relation. Trade-offs between approximation in bandlimit (in the Hermite sense) and size of the support region are addressed. Numerical experiments are presented that show the feasibility and utility of our approach. Generalizations to any family of orthogonal polynomials are outlined. Applications to various problems in tomographic reconstruction, including the determination of protein structure, are discussed. PMID:20027202

  6. Fast Overcurrent Tripping Circuit

    NASA Technical Reports Server (NTRS)

    Sullender, Craig C.; Davies, Bryan L.; Osborn, Stephen H.

    1993-01-01

    Fast overcurrent tripping circuit designed for incorporation into power metal oxide/semiconductor field-effect transistor (MOSFET) switching circuit. Serves as fast electronic circuit breaker by sensing voltage across MOSFET's during conduction and switching MOSFET's off within 1 microsecond after voltage exceeds reference value corresponding to tripping current. Acts more quickly than Hall-effect current sensor and, in comparison with shunt current-measuring circuits, smaller and consumes less power. Also ignores initial transient overcurrents during first 5 microseconds of switching cycle.

  7. Catalytic electron transport in Chromatium vinosum [NiFe]-hydrogenase: application of voltammetry in detecting redox-active centers and establishing that hydrogen oxidation is very fast even at potentials close to the reversible H+/H2 value.

    PubMed

    Pershad, H R; Duff, J L; Heering, H A; Duin, E C; Albracht, S P; Armstrong, F A

    1999-07-13

    The nickel-iron hydrogenase from Chromatium vinosum adsorbs at a pyrolytic graphite edge-plane (PGE) electrode and catalyzes rapid interconversion of H(+)((aq)) and H(2) at potentials expected for the half-cell reaction 2H(+) right arrow over left arrow H(2), i.e., without the need for overpotentials. The voltammetry mirrors characteristics determined by conventional methods, while affording the capabilities for exquisite control and measurement of potential-dependent activities and substrate-product mass transport. Oxidation of H(2) is extremely rapid; at 10% partial pressure H(2), mass transport control persists even at the highest electrode rotation rates. The turnover number for H(2) oxidation lies in the range of 1500-9000 s(-)(1) at 30 degrees C (pH 5-8), which is significantly higher than that observed using methylene blue as the electron acceptor. By contrast, proton reduction is slower and controlled by processes occurring in the enzyme. Carbon monoxide, which binds reversibly to the NiFe site in the active form, inhibits electrocatalysis and allows improved definition of signals that can be attributed to the reversible (non-turnover) oxidation and reduction of redox centers. One signal, at -30 mV vs SHE (pH 7.0, 30 degrees C), is assigned to the [3Fe-4S](+/0) cluster on the basis of potentiometric measurements. The second, at -301 mV and having a 1. 5-2.5-fold greater amplitude, is tentatively assigned to the two [4Fe-4S](2+/+) clusters with similar reduction potentials. No other redox couples are observed, suggesting that these two sets of centers are the only ones in CO-inhibited hydrogenase capable of undergoing simple rapid cycling of their redox states. With the buried NiFe active site very unlikely to undergo direct electron exchange with the electrode, at least one and more likely each of the three iron-sulfur clusters must serve as relay sites. The fact that H(2) oxidation is rapid even at potentials nearly 300 mV more negative than the reduction

  8. Fast current ramp experiments on TFTR

    SciTech Connect

    Fredrickson, E.D.; McGuire, K.; Goldston, R.J.; Bell, M.; Grek, B.; Johnson, D.; Morris, A.W.; Stauffer, F.J.; Taylor, G.; Zarnstorff, M.C.

    1987-05-01

    Electron heat transport on TFTR and other tokamaks is several orders of magnitude larger than neoclassical calculations would predict. Despite considerable effort, there is still no clear theoretical understanding of this anomalous transport. The electron temperature profile T/sub e/(r), shape has shown a marked consistency on many machines, including TFTR, for a wide range of plasma parameters and heating profiles. This could be an important clue as to the process responsible for this enhanced thermal transport. In this paper 'profile consistency' in TFTR is described and an experiment which uses a fast current ramp to transiently decouple the current density profile J(r), and the T/sub e/(r) profiles is discussed. From this experiment the influence of J(r) on electron temperature profile consistency can be determined.

  9. Radiation Transport

    SciTech Connect

    Urbatsch, Todd James

    2015-06-15

    We present an overview of radiation transport, covering terminology, blackbody raditation, opacities, Boltzmann transport theory, approximations to the transport equation. Next we introduce several transport methods. We present a section on Caseology, observing transport boundary layers. We briefly broach topics of software development, including verification and validation, and we close with a section on high energy-density experiments that highlight and support radiation transport.

  10. Fast focus field calculations

    NASA Astrophysics Data System (ADS)

    Leutenegger, Marcel; Geissbuehler, Matthias; Märki, Iwan; Leitgeb, Rainer A.; Lasser, Theo

    2008-02-01

    We present a method for fast calculation of the electromagnetic field near the focus of an objective with a high numerical aperture (NA). Instead of direct integration, the vectorial Debye diffraction integral is evaluated with the fast Fourier transform for calculating the electromagnetic field in the entire focal region. We generalize this concept with the chirp z transform for obtaining a flexible sampling grid and an additional gain in computation speed. Under the conditions for the validity of the Debye integral representation, our method yields the amplitude, phase and polarization of the focus field for an arbitrary paraxial input field in the aperture of the objective. Our fast calculation method is particularly useful for engineering the point-spread function or for fast image deconvolution. We present several case studies by calculating the focus fields of high NA oil immersion objectives for various amplitude, polarization and phase distributions of the input field. In addition, the calculation of an extended polychromatic focus field generated by a Bessel beam is presented. This extended focus field is of particular interest for Fourier domain optical coherence tomography because it preserves a lateral resolution of a few micrometers over an axial distance in the millimeter range.

  11. Fast ForWord.

    ERIC Educational Resources Information Center

    Education Commission of the States, Denver, CO.

    This paper provides an overview of Fast ForWord, a CD-ROM and Internet-based training program for children (pre-K to grade 8) with language and reading problems that helps children rapidly build oral language comprehension and other critical skills necessary for learning to read or becoming a better reader. With the help of computers, speech…

  12. The Integral Fast Reactor

    SciTech Connect

    Till, C.E.; Chang, Y.I. ); Lineberry, M.J. )

    1990-01-01

    Argonne National Laboratory, since 1984, has been developing the Integral Fast Reactor (IFR). This paper will describe the way in which this new reactor concept came about; the technical, public acceptance, and environmental issues that are addressed by the IFR; the technical progress that has been made; and our expectations for this program in the near term. 5 refs., 3 figs.

  13. FAST - FREEDOM ASSEMBLY SEQUENCING TOOL PROTOTYPE

    NASA Technical Reports Server (NTRS)

    Borden, C. S.

    1994-01-01

    FAST is a project management tool designed to optimize the assembly sequence of Space Station Freedom. An appropriate assembly sequence coordinates engineering, design, utilization, transportation availability, and operations requirements. Since complex designs tend to change frequently, FAST assesses the system level effects of detailed changes and produces output metrics that identify preferred assembly sequences. FAST incorporates Space Shuttle integration, Space Station hardware, on-orbit operations, and programmatic drivers as either precedence relations or numerical data. Hardware sequencing information can either be input directly and evaluated via the "specified" mode of operation or evaluated from the input precedence relations in the "flexible" mode. In the specified mode, FAST takes as its input a list of the cargo elements assigned to each flight. The program determines positions for the cargo elements that maximize the center of gravity (c.g.) margin. These positions are restricted by the geometry of the cargo elements and the location of attachment fittings both in the orbiter and on the cargo elements. FAST calculates every permutation of cargo element location according to its height, trunnion fitting locations, and required intercargo element spacing. Each cargo element is tested in both its normal and reversed orientation (rotated 180 degrees). The best solution is that which maximizes the c.g. margin for each flight. In the flexible mode, FAST begins with the first flight and determines all feasible combinations of cargo elements according to mass, volume, EVA, and precedence relation constraints. The program generates an assembly sequence that meets mass, volume, position, EVA, and precedence constraints while minimizing the total number of Shuttle flights required. Issues associated with ground operations, spacecraft performance, logistics requirements and user requirements will be addressed in future versions of the model. FAST is written in C

  14. Magnetically guided fast electrons in cylindrically compressed matter.

    PubMed

    Pérez, F; Debayle, A; Honrubia, J; Koenig, M; Batani, D; Baton, S D; Beg, F N; Benedetti, C; Brambrink, E; Chawla, S; Dorchies, F; Fourment, C; Galimberti, M; Gizzi, L A; Gremillet, L; Heathcote, R; Higginson, D P; Hulin, S; Jafer, R; Koester, P; Labate, L; Lancaster, K L; MacKinnon, A J; MacPhee, A G; Nazarov, W; Nicolai, P; Pasley, J; Ramis, R; Richetta, M; Santos, J J; Sgattoni, A; Spindloe, C; Vauzour, B; Vinci, T; Volpe, L

    2011-08-01

    Fast electrons produced by a 10 ps, 160 J laser pulse through laser-compressed plastic cylinders are studied experimentally and numerically in the context of fast ignition. K(α)-emission images reveal a collimated or scattered electron beam depending on the initial density and the compression timing. A numerical transport model shows that implosion-driven electrical resistivity gradients induce strong magnetic fields able to guide the electrons. The good agreement with measured beam sizes provides the first experimental evidence for fast-electron magnetic collimation in laser-compressed matter. PMID:21902333

  15. Chamber transport

    SciTech Connect

    OLSON,CRAIG L.

    2000-05-17

    Heavy ion beam transport through the containment chamber plays a crucial role in all heavy ion fusion (HIF) scenarios. Here, several parameters are used to characterize the operating space for HIF beams; transport modes are assessed in relation to evolving target/accelerator requirements; results of recent relevant experiments and simulations of HIF transport are summarized; and relevant instabilities are reviewed. All transport options still exist, including (1) vacuum ballistic transport, (2) neutralized ballistic transport, and (3) channel-like transport. Presently, the European HIF program favors vacuum ballistic transport, while the US HIF program favors neutralized ballistic transport with channel-like transport as an alternate approach. Further transport research is needed to clearly guide selection of the most attractive, integrated HIF system.

  16. Ab initio prediction of fast non-equilibrium transport of nascent polarons in SrI2: a key to high-performance scintillation [First-principles study of hole polaron formation and migration in strontium iodide

    DOE PAGESBeta

    Zhou, Fei; Sadigh, Babak; Aberg, Daniel; Erhart, Paul

    2016-08-12

    The excellent light yield proportionality of europium-doped strontium iodide (SrI2:Eu) has resulted in state-of-the-art γ-ray detectors with remarkably high-energy resolution, far exceeding that of most halide compounds. In this class of materials, the formation of self-trapped hole polarons is very common. However, polaron formation is usually expected to limit carrier mobilities and has been associated with poor scintillator light-yield proportionality and resolution. Here using a recently developed first-principles method, we perform an unprecedented study of polaron transport in SrI2, both for equilibrium polarons, as well as nascent polarons immediately following a self-trapping event. We propose a rationale for the unexpectedmore » high-energy resolution of SrI2. We identify nine stable hole polaron configurations, which consist of dimerised iodine pairs with polaron-binding energies of up to 0.5 eV. They are connected by a complex potential energy landscape that comprises 66 unique nearest-neighbour migration paths. Ab initio molecular dynamics simulations reveal that a large fraction of polarons is born into configurations that migrate practically barrier free at room temperature. Consequently, carriers created during γ-irradiation can quickly diffuse away reducing the chance for nonlinear recombination, the primary culprit for non-proportionality and resolution reduction. We conclude that the flat, albeit complex, landscape for polaron migration in SrI2 is a key for understanding its outstanding performance. This insight provides important guidance not only for the future development of high-performance scintillators but also of other materials, for which large polaron mobilities are crucial such as batteries and solid-state ionic conductors.« less

  17. Fast electrochemical actuator

    NASA Astrophysics Data System (ADS)

    Uvarov, I. V.; Postnikov, A. V.; Svetovoy, V. B.

    2016-03-01

    Lack of fast and strong microactuators is a well-recognized problem in MEMS community. Electrochemical actuators can develop high pressure but they are notoriously slow. Water electrolysis produced by short voltage pulses of alternating polarity can overcome the problem of slow gas termination. Here we demonstrate an actuation regime, for which the gas pressure is relaxed just for 10 μs or so. The actuator consists of a microchamber filled with the electrolyte and covered with a flexible membrane. The membrane bends outward when the pressure in the chamber increases. Fast termination of gas and high pressure developed in the chamber are related to a high density of nanobubbles in the chamber. The physical processes happening in the chamber are discussed so as problems that have to be resolved for practical applications of this actuation regime. The actuator can be used as a driving engine for microfluidics.

  18. Fast Ion Conductors

    NASA Astrophysics Data System (ADS)

    Chadwick, Alan V.

    Fast ion conductors, sometimes referred to as superionic conductors or solid electrolytes, are solids with ionic conductivities that are comparable to those found in molten salts and aqueous solutions of strong electrolytes, i.e., 10-2-10 S cm-1. Such materials have been known of for a very long time and some typical examples of the conductivity are shown in Fig. 1, along with sodium chloride as the archetypal normal ionic solid. Faraday [1] first noted the high conductivity of solid lead fluoride (PbF2) and silver sulphide (Ag2S) in the 1830s and silver iodide was known to be unusually high ionic conductor to the German physicists early in the 1900s. However, the materials were regarded as anomalous until the mid 1960s when they became the focus of intense interest to academics and technologists and they have remained at the forefront of materials research [2-4]. The academic aim is to understand the fundamental origin of fast ion behaviour and the technological goal is to utilize the properties in applications, particularly in energy applications such as the electrolyte membranes in solid-state batteries and fuel cells, and in electrochemical sensors. The last four decades has seen an expansion of the types of material that exhibit fast ion behaviour that now extends beyond simple binary ionic crystals to complex solids and even polymeric materials. Over this same period computer simulations of solids has also developed (in fact these methods and the interest in fast ion conductors were almost coincidental in their time of origin) and the techniques have played a key role in this area of research.

  19. PHENIX Fast TOF

    SciTech Connect

    Soha, Aria; Chiu, Mickey; Mannel, Eric; Stoll, Sean; Lynch, Don; Boose, Steve; Northacker, Dave; Alfred, Marcus; Lindesay, James; Chujo, Tatsuya; Inaba, Motoi; Nonaka, Toshihiro; Sato, Wataru; Sakatani, Ikumi; Hirano, Masahiro; Choi, Ihnjea

    2014-01-15

    This is a technical scope of work (TSW) between the Fermi National Accelerator Laboratory (Fermilab) and the experimenters of PHENIX Fast TOF group who have committed to participate in beam tests to be carried out during the FY2014 Fermilab Test Beam Facility program. The goals for this test beam experiment are to verify the timing performance of the two types of time-of-flight detector prototypes.

  20. Fast track evaluation methodology.

    PubMed

    Duke, J R

    1991-06-01

    Evaluating hospital information systems has taken a variety of forms since the initial development and use of automation. The process itself has moved from a hardware-based orientation controlled by data processing professionals to systems solutions and a user-driven process overseen by management. At Harbor Hospital Center in Baltimore, a fast track methodology has been introduced to shorten system evaluation time to meet the rapid changes that constantly affect the healthcare industry.

  1. Transport proteins.

    PubMed

    Thatcher, Jack D

    2013-04-16

    This Teaching Resource provides and describes two animated lessons that illustrate general properties of transport proteins. The lesson called "transport protein classes" depicts major classes and subclasses of transport proteins. The "transporters, mechanism of action" lesson explains how transporters and P class ATPase (adenosine triphosphatase) pumps function. These animations serve as valuable resources for any collegiate-level course that describes these important factors. Courses that might use them include introductory biology, biochemistry, cell biology, physiology, and biophysics.

  2. Fast Track Study

    NASA Technical Reports Server (NTRS)

    1996-01-01

    The NASA Fast Track Study supports the efforts of a Special Study Group (SSG) made up of members of the Advanced Project Management Class number 23 (APM-23) that met at the Wallops Island Management Education Center from April 28 - May 8, 1996. Members of the Class expressed interest to Mr. Vem Weyers in having an input to the NASA Policy Document (NPD) 7120.4, that will replace NASA Management Institute (NMI) 7120.4, and the NASA Program/Project Management Guide. The APM-23 SSG was tasked with assisting in development of NASA policy on managing Fast Track Projects, defined as small projects under $150 million and completed within three years. 'Me approach of the APM-23 SSG was to gather data on successful projects working in a 'Better, Faster, Cheaper' environment, within and outside of NASA and develop the Fast Track Project section of the NASA Program/Project Management Guide. Fourteen interviews and four other data gathering efforts were conducted by the SSG, and 16 were conducted by Strategic Resources, Inc. (SRI), including five interviews at the Jet Propulsion Laboratory (JPL) and one at the Applied Physics Laboratory (APL). The interviews were compiled and analyzed for techniques and approaches commonly used to meet severe cost and schedule constraints.

  3. The fast Hartley transform

    NASA Astrophysics Data System (ADS)

    Mar, Mark H.

    1990-11-01

    The purpose of this paper is to report the results of testing the fast Hartley transform (FHT) and comparing it with the fast Fourier transform (FFT). All the definitions and equations in this paper are quoted and cited from the series of references. The author of this report developed a FORTRAN program which computes the Hartley transform. He tested the program with a generalized electromagnetic pulse waveform and verified the results with the known value. Fourier analysis is an essential tool to obtain frequency domain information from transient time domain signals. The FFT is a popular tool to process many of today's audio and electromagnetic signals. System frequency response, digital filtering of signals, and signal power spectrum are the most practical applications of the FFT. However, the Fourier integral transform of the FFT requires computer resources appropriate for the complex arithmetic operations. On the other hand, the FHT can accomplish the same results faster and requires fewer computer resources. The FHT is twice as fast as the FFT, uses only half the computer resources, and so could be more useful than the FFT in typical applications such as spectral analysis, signal processing, and convolution. This paper presents a FORTRAN computer program for the FHT algorithm along with a brief description and compares the results and performance of the FHT and the FFT algorithms.

  4. Fasting - the ultimate diet?

    PubMed

    Johnstone, A M

    2007-05-01

    Adult humans often undertake acute fasts for cosmetic, religious or medical reasons. For example, an estimated 14% of US adults have reported using fasting as a means to control body weight and this approach has long been advocated as an intermittent treatment for gross refractory obesity. There are unique historical data sets on extreme forms of food restriction that give insight into the consequences of starvation or semi-starvation in previously healthy, but usually non-obese subjects. These include documented medical reports on victims of hunger strike, famine and prisoners of war. Such data provide a detailed account on how the body adapts to prolonged starvation. It has previously been shown that fasting for the biblical period of 40 days and 40 nights is well within the overall physiological capabilities of a healthy adult. However, the specific effects on the human body and mind are less clearly documented, either in the short term (hours) or in the longer term (days). This review asks the following three questions, pertinent to any weight-loss therapy, (i) how effective is the regime in achieving weight loss, (ii) what impact does it have on psychology? and finally, (iii) does it work long-term? PMID:17444963

  5. Fast Neutral Pressure Gauges in NSTX

    SciTech Connect

    R. Raman; H.W. Kugel; R. Gernhardt; T. Provost; T.R. Jarboe; V. Soukhanovskii

    2004-04-26

    Successful operation in NSTX of two prototype fast-response micro ionization gauges during plasma operations has motivated us to install five gauges at different toroidal and poloidal locations to measure the edge neutral pressure and its dependence on the type of discharge (L-mode, H-mode, CHI) and the fueling method and location. The edge neutral pressure is also used as an input to the transport analysis codes TRANSP and DEGAS-2. The modified PDX-type Penning gauges are well suited for pressure measurements in the NSTX divertor where the toroidal field is relatively high. Behind the NSTX outer divertor plates where the field is lower, an unshielded fast ion gauge of a new design has been installed. This gauge was developed after laboratory testing of several different designs in a vacuum chamber with applied magnetic fields.

  6. Neighborhood fast food availability and fast food consumption

    PubMed Central

    Oexle, Nathalie; Barnes, Timothy L; Blake, Christine E; Bell, Bethany A; Liese, Angela D

    2015-01-01

    Recent nutritional and public health research has focused on how the availability of various types of food in a person’s immediate area or neighborhood influences his or her food choices and eating habits. It has been theorized that people living in areas with a wealth of unhealthy fast-food options may show higher levels of fast-food consumption, a factor that often coincides with being overweight or obese. However, measuring food availability in a particular area is difficult to achieve consistently: there may be differences in the strict physical locations of food options as compared to how individuals perceive their personal food availability, and various studies may use either one or both of these measures. The aim of this study was to evaluate the association between weekly fast-food consumption and both a person’s perceived availability of fast-food and an objective measure of fast-food presence—Geographic Information Systems (GIS)—within that person’s neighborhood. A randomly selected population-based sample of eight counties in South Carolina was used to conduct a cross-sectional telephone survey assessing self-report fast-food consumption and perceived availability of fast food. GIS was used to determine the actual number of fast-food outlets within each participant’s neighborhood. Using multinomial logistic regression analyses, we found that neither perceived availability nor GIS-based presence of fast-food was significantly associated with weekly fast-food consumption. Our findings indicate that availability might not be the dominant factor influencing fast-food consumption. We recommend using subjective availability measures and considering individual characteristics that could influence both perceived availability of fast food and its impact on fast-food consumption. If replicated, our findings suggest that interventions aimed at reducing fast-food consumption by limiting neighborhood fast-food availability might not be completely

  7. Neighborhood fast food availability and fast food consumption.

    PubMed

    Oexle, Nathalie; Barnes, Timothy L; Blake, Christine E; Bell, Bethany A; Liese, Angela D

    2015-09-01

    Recent nutritional and public health research has focused on how the availability of various types of food in a person's immediate area or neighborhood influences his or her food choices and eating habits. It has been theorized that people living in areas with a wealth of unhealthy fast-food options may show higher levels of fast-food consumption, a factor that often coincides with being overweight or obese. However, measuring food availability in a particular area is difficult to achieve consistently: there may be differences in the strict physical locations of food options as compared to how individuals perceive their personal food availability, and various studies may use either one or both of these measures. The aim of this study was to evaluate the association between weekly fast-food consumption and both a person's perceived availability of fast-food and an objective measure of fast-food presence - Geographic Information Systems (GIS) - within that person's neighborhood. A randomly selected population-based sample of eight counties in South Carolina was used to conduct a cross-sectional telephone survey assessing self-report fast-food consumption and perceived availability of fast food. GIS was used to determine the actual number of fast-food outlets within each participant's neighborhood. Using multinomial logistic regression analyses, we found that neither perceived availability nor GIS-based presence of fast-food was significantly associated with weekly fast-food consumption. Our findings indicate that availability might not be the dominant factor influencing fast-food consumption. We recommend using subjective availability measures and considering individual characteristics that could influence both perceived availability of fast food and its impact on fast-food consumption. If replicated, our findings suggest that interventions aimed at reducing fast-food consumption by limiting neighborhood fast-food availability might not be completely effective.

  8. Neighborhood fast food availability and fast food consumption.

    PubMed

    Oexle, Nathalie; Barnes, Timothy L; Blake, Christine E; Bell, Bethany A; Liese, Angela D

    2015-09-01

    Recent nutritional and public health research has focused on how the availability of various types of food in a person's immediate area or neighborhood influences his or her food choices and eating habits. It has been theorized that people living in areas with a wealth of unhealthy fast-food options may show higher levels of fast-food consumption, a factor that often coincides with being overweight or obese. However, measuring food availability in a particular area is difficult to achieve consistently: there may be differences in the strict physical locations of food options as compared to how individuals perceive their personal food availability, and various studies may use either one or both of these measures. The aim of this study was to evaluate the association between weekly fast-food consumption and both a person's perceived availability of fast-food and an objective measure of fast-food presence - Geographic Information Systems (GIS) - within that person's neighborhood. A randomly selected population-based sample of eight counties in South Carolina was used to conduct a cross-sectional telephone survey assessing self-report fast-food consumption and perceived availability of fast food. GIS was used to determine the actual number of fast-food outlets within each participant's neighborhood. Using multinomial logistic regression analyses, we found that neither perceived availability nor GIS-based presence of fast-food was significantly associated with weekly fast-food consumption. Our findings indicate that availability might not be the dominant factor influencing fast-food consumption. We recommend using subjective availability measures and considering individual characteristics that could influence both perceived availability of fast food and its impact on fast-food consumption. If replicated, our findings suggest that interventions aimed at reducing fast-food consumption by limiting neighborhood fast-food availability might not be completely effective. PMID

  9. Hispanics in Fast Food Jobs.

    ERIC Educational Resources Information Center

    Charner, Ivan; Fraser, Bryna Shore

    A study examined the employment of Hispanics in the fast-food industry. Data were obtained from a national survey of employees at 279 fast-food restaurants from seven companies in which 194 (4.2 percent) of the 4,660 respondents reported being Hispanic. Compared with the total sample, Hispanic fast-food employees were slightly less likely to be…

  10. Fast ion profile stiffness due to the resonance overlap of multiple Alfvén eigenmodes

    NASA Astrophysics Data System (ADS)

    Todo, Y.; Van Zeeland, M. A.; Heidbrink, W. W.

    2016-11-01

    Fast ion pressure profiles flattened by multiple Alfvén eigenmodes (AEs) are investigated for various neutral beam deposition powers in a multi-phase simulation, which is a combination of classical simulation and hybrid simulation for energetic particles interacting with a magnetohydrodynamic fluid. Monotonic degradation of fast ion confinement and fast ion profile stiffness is found with increasing beam deposition power. The confinement degradation and profile stiffness are caused by a sudden increase in fast ion transport flux brought about by AEs for fast ion pressure gradients above a critical value. The critical pressure gradient and the corresponding beam deposition power depend on the radial location. The fast ion pressure gradient stays moderately above the critical value, and the profiles of the fast ion pressure and fast ion transport flux spread radially outward from the inner region, where the beam is injected. It is found that the square root of the MHD fluctuation energy is proportional to the beam deposition power. Analysis of the time evolutions of the fast ion energy flux profiles reveals that intermittent avalanches take place with contributions from the multiple eigenmodes. Surface of section plots demonstrate that the resonance overlap of multiple eigenmodes accounts for the sudden increase in fast ion transport with increasing beam power. The critical gradient and critical beam power for the profile stiffness are substantially higher than the marginal stability threshold.

  11. Bi-Directional Fast Charging Study Report

    SciTech Connect

    Tyler Gray

    2012-02-01

    This report details the hardware and software infrastructure needed to demonstrate the possibility of utilizing battery power in plug-in hybrid electric vehicles (PHEVs) and electric vehicles (EVs) with a bi directional fast charger to support/offset peak building loads. This document fulfills deliverable requirements for Tasks 1.2.1.2, 1.2.1.3, and 1.2.1.4 of Statement of Work (SOW) No.5799 for Electric Transportation Engineering Corporation, now ECOtality North America (NA) support for the Idaho National Laboratory (INL).

  12. Fast infrared response of YBCO thin films

    NASA Technical Reports Server (NTRS)

    Ballentine, P. H.; Kadin, A. M.; Donaldson, W. R.; Scofield, J. H.; Bajuk, L.

    1990-01-01

    The response to short infrared pulses of some epitaxial YBCO films prepared by sputter deposition and by electron-beam evaporation is reported. The response is found to be essentially bolometric on the ns timescale, with some indirect hints of nonequilibrium electron transport on the ps scale. Fast switching could be obtained either by biasing the switch close to the critical current or by cooling the film below about 20 K. These results are encouraging for potential application to a high-current optically-triggered opening switch.

  13. Simplified fast neutron dosimeter

    DOEpatents

    Sohrabi, Mehdi

    1979-01-01

    Direct fast-neutron-induced recoil and alpha particle tracks in polycarbonate films may be enlarged for direct visual observation and automated counting procedures employing electrochemical etching techniques. Electrochemical etching is, for example, carried out in a 28% KOH solution at room temperature by applying a 2000 V peak-to-peak voltage at 1 kHz frequency. Such recoil particle amplification can be used for the detection of wide neutron dose ranges from 1 mrad. to 1000 rads. or higher, if desired.

  14. The fast encryption package

    NASA Technical Reports Server (NTRS)

    Bishop, Matt

    1988-01-01

    The organization of some tools to help improve passwork security at a UNIX-based site is described along with how to install and use them. These tools and their associated library enable a site to force users to pick reasonably safe passwords (safe being site configurable) and to enable site management to try to crack existing passworks. The library contains various versions of a very fast implementation of the Data Encryption Standard and of the one-way encryption functions used to encryp the password.

  15. Fast neutron dosimetry

    SciTech Connect

    DeLuca, P.M. Jr.; Pearson, D.W.

    1992-01-01

    This progress report concentrates on two major areas of dosimetry research: measurement of fast neutron kerma factors for several elements for monochromatic and white spectrum neutron fields and determination of the response of thermoluminescent phosphors to various ultra-soft X-ray energies and beta-rays. Dr. Zhixin Zhou from the Shanghai Institute of Radiation Medicine, People's Republic of China brought with him special expertise in the fabrication and use of ultra-thin TLD materials. Such materials are not available in the USA. The rather unique properties of these materials were investigated during this grant period.

  16. Fast quench reactor method

    SciTech Connect

    Detering, Brent A.; Donaldson, Alan D.; Fincke, James R.; Kong, Peter C.; Berry, Ray A.

    1999-01-01

    A fast quench reaction includes a reactor chamber having a high temperature heating means such as a plasma torch at its inlet and a means of rapidly expanding a reactant stream, such as a restrictive convergent-divergent nozzle at its outlet end. Metal halide reactants are injected into the reactor chamber. Reducing gas is added at different stages in the process to form a desired end product and prevent back reactions. The resulting heated gaseous stream is then rapidly cooled by expansion of the gaseous stream.

  17. Fast quench reactor method

    DOEpatents

    Detering, B.A.; Donaldson, A.D.; Fincke, J.R.; Kong, P.C.; Berry, R.A.

    1999-08-10

    A fast quench reaction includes a reactor chamber having a high temperature heating means such as a plasma torch at its inlet and a means of rapidly expanding a reactant stream, such as a restrictive convergent-divergent nozzle at its outlet end. Metal halide reactants are injected into the reactor chamber. Reducing gas is added at different stages in the process to form a desired end product and prevent back reactions. The resulting heated gaseous stream is then rapidly cooled by expansion of the gaseous stream. 8 figs.

  18. FAST NEUTRONIC REACTOR

    DOEpatents

    Snell, A.H.

    1957-12-01

    This patent relates to a reactor and process for carrying out a controlled fast neutron chain reaction. A cubical reactive mass, weighing at least 920 metric tons, of uranium metal containing predominantly U/sup 238/ and having a U/sup 235/ content of at least 7.63% is assembled and the maximum neutron reproduction ratio is limited to not substantially over 1.01 by insertion and removal of a varying amount of boron, the reactive mass being substantially freed of moderator.

  19. Fast separable nonlocal means

    NASA Astrophysics Data System (ADS)

    Ghosh, Sanjay; Chaudhury, Kunal N.

    2016-03-01

    We propose a simple and fast algorithm called PatchLift for computing distances between patches (contiguous block of samples) extracted from a given one-dimensional signal. PatchLift is based on the observation that the patch distances can be efficiently computed from a matrix that is derived from the one-dimensional signal using lifting; importantly, the number of operations required to compute the patch distances using this approach does not scale with the patch length. We next demonstrate how PatchLift can be used for patch-based denoising of images corrupted with Gaussian noise. In particular, we propose a separable formulation of the classical nonlocal means (NLM) algorithm that can be implemented using PatchLift. We demonstrate that the PatchLift-based implementation of separable NLM is a few orders faster than standard NLM and is competitive with existing fast implementations of NLM. Moreover, its denoising performance is shown to be consistently superior to that of NLM and some of its variants, both in terms of peak signal-to-noise ratio/structural similarity index and visual quality.

  20. Fast SCR Thyratron Driver

    SciTech Connect

    Nguyen, M.N.; /SLAC

    2007-06-18

    As part of an improvement project on the linear accelerator at SLAC, it was necessary to replace the original thyratron trigger generator, which consisted of two chassis, two vacuum tubes, and a small thyratron. All solid-state, fast rise, and high voltage thyratron drivers, therefore, have been developed and built for the 244 klystron modulators. The rack mounted, single chassis driver employs a unique way to control and generate pulses through the use of an asymmetric SCR, a PFN, a fast pulse transformer, and a saturable reactor. The resulting output pulse is 2 kV peak into 50 {Omega} load with pulse duration of 1.5 {mu}s FWHM at 180 Hz. The pulse risetime is less than 40 ns with less than 1 ns jitter. Various techniques are used to protect the SCR from being damaged by high voltage and current transients due to thyratron breakdowns. The end-of-line clipper (EOLC) detection circuit is also integrated into this chassis to interrupt the modulator triggering in the event a high percentage of line reflections occurred.

  1. Fast Fourier transform telescope

    SciTech Connect

    Tegmark, Max; Zaldarriaga, Matias

    2009-04-15

    We propose an all-digital telescope for 21 cm tomography, which combines key advantages of both single dishes and interferometers. The electric field is digitized by antennas on a rectangular grid, after which a series of fast Fourier transforms recovers simultaneous multifrequency images of up to half the sky. Thanks to Moore's law, the bandwidth up to which this is feasible has now reached about 1 GHz, and will likely continue doubling every couple of years. The main advantages over a single dish telescope are cost and orders of magnitude larger field-of-view, translating into dramatically better sensitivity for large-area surveys. The key advantages over traditional interferometers are cost (the correlator computational cost for an N-element array scales as Nlog{sub 2}N rather than N{sup 2}) and a compact synthesized beam. We argue that 21 cm tomography could be an ideal first application of a very large fast Fourier transform telescope, which would provide both massive sensitivity improvements per dollar and mitigate the off-beam point source foreground problem with its clean beam. Another potentially interesting application is cosmic microwave background polarization.

  2. School Transportation.

    ERIC Educational Resources Information Center

    Executive Educator, 1990

    1990-01-01

    This special section on student transportation offers a case study of a school system that recycles buses for safety drills; articles on fuel-saving strategies, the pros and cons of contracting for transportation services or operating a publicly owned bus fleet, and advice on full cost accounting for transportation costs; and a transportation…

  3. Transport Experiments

    NASA Technical Reports Server (NTRS)

    Hall, Timothy M.; Wuebbles, Donald J.; Boering, Kristie A.; Eckman, Richard S.; Lerner, Jean; Plumb, R. Alan; Rind, David H.; Rinsland, Curtis P.; Waugh, Darryn W.; Wei, Chu-Feng

    1999-01-01

    MM II defined a series of experiments to better understand and characterize model transport and to assess the realism of this transport by comparison to observations. Measurements from aircraft, balloon, and satellite, not yet available at the time of MM I [Prather and Remsberg, 1993], provide new and stringent constraints on model transport, and address the limits of our transport modeling abilities. Simulations of the idealized tracers the age spectrum, and propagating boundary conditions, and conserved HSCT-like emissions probe the relative roles of different model transport mechanisms, while simulations of SF6 and C02 make the connection to observations. Some of the tracers are related, and transport diagnostics such as the mean age can be derived from more than one of the experiments for comparison to observations. The goals of the transport experiments are: (1) To isolate the effects of transport in models from other processes; (2) To assess model transport for realistic tracers (such as SF6 and C02) for comparison to observations; (3) To use certain idealized tracers to isolate model mechanisms and relationships to atmospheric chemical perturbations; (4) To identify strengths and weaknesses of the treatment of transport processes in the models; (5) To relate evaluated shortcomings to aspects of model formulation. The following section are included:Executive Summary, Introduction, Age Spectrum, Observation, Tropical Transport in Models, Global Mean Age in Models, Source-Transport Covariance, HSCT "ANOY" Tracer Distributions, and Summary and Conclusions.

  4. Faster Heavy Ion Transport for HZETRN

    NASA Technical Reports Server (NTRS)

    Slaba, Tony C.

    2013-01-01

    The deterministic particle transport code HZETRN was developed to enable fast and accurate space radiation transport through materials. As more complex transport solutions are implemented for neutrons, light ions (Z < 2), mesons, and leptons, it is important to maintain overall computational efficiency. In this work, the heavy ion (Z > 2) transport algorithm in HZETRN is reviewed, and a simple modification is shown to provide an approximate 5x decrease in execution time for galactic cosmic ray transport. Convergence tests and other comparisons are carried out to verify that numerical accuracy is maintained in the new algorithm.

  5. Fast Food Jobs. National Study of Fast Food Employment.

    ERIC Educational Resources Information Center

    Charner, Ivan; Fraser, Bryna Shore

    A study examined employment in the fast-food industry. The national survey collected data from employees at 279 fast-food restaurants from seven companies. Female employees outnumbered males by two to one. The ages of those fast-food employees in the survey sample ranged from 14 to 71, with fully 70 percent being in the 16- to 20-year-old age…

  6. An algorithm for fast DNS cavitating flows simulations using homogeneous mixture approach

    NASA Astrophysics Data System (ADS)

    Žnidarčič, A.; Coutier-Delgosha, O.; Marquillie, M.; Dular, M.

    2015-12-01

    A new algorithm for fast DNS cavitating flows simulations is developed. The algorithm is based on Kim and Moin projection method form. Homogeneous mixture approach with transport equation for vapour volume fraction is used to model cavitation and various cavitation models can be used. Influence matrix and matrix diagonalisation technique enable fast parallel computations.

  7. Microstructure design for fast oxygen conduction

    SciTech Connect

    Aidhy, Dilpuneet S.; Weber, William J.

    2015-11-11

    Research from the last decade has shown that in designing fast oxygen conducting materials for electrochemical applications has largely shifted to microstructural features, in contrast to material-bulk. In particular, understanding oxygen energetics in heterointerface materials is currently at the forefront, where interfacial tensile strain is being considered as the key parameter in lowering oxygen migration barriers. Nanocrystalline materials with high densities of grain boundaries have also gathered interest that could possibly allow leverage over excess volume at grain boundaries, providing fast oxygen diffusion channels similar to those previously observed in metals. In addition, near-interface phase transformations and misfit dislocations are other microstructural phenomenon/features that are being explored to provide faster diffusion. In this review, the current understanding on oxygen energetics, i.e., thermodynamics and kinetics, originating from these microstructural features is discussed. Moreover, our experimental observations, theoretical predictions and novel atomistic mechanisms relevant to oxygen transport are highlighted. In addition, the interaction of dopants with oxygen vacancies in the presence of these new microstructural features, and their future role in the design of future fast-ion conductors, is outlined.

  8. Microstructure design for fast oxygen conduction

    DOE PAGESBeta

    Aidhy, Dilpuneet S.; Weber, William J.

    2015-11-11

    Research from the last decade has shown that in designing fast oxygen conducting materials for electrochemical applications has largely shifted to microstructural features, in contrast to material-bulk. In particular, understanding oxygen energetics in heterointerface materials is currently at the forefront, where interfacial tensile strain is being considered as the key parameter in lowering oxygen migration barriers. Nanocrystalline materials with high densities of grain boundaries have also gathered interest that could possibly allow leverage over excess volume at grain boundaries, providing fast oxygen diffusion channels similar to those previously observed in metals. In addition, near-interface phase transformations and misfit dislocations aremore » other microstructural phenomenon/features that are being explored to provide faster diffusion. In this review, the current understanding on oxygen energetics, i.e., thermodynamics and kinetics, originating from these microstructural features is discussed. Moreover, our experimental observations, theoretical predictions and novel atomistic mechanisms relevant to oxygen transport are highlighted. In addition, the interaction of dopants with oxygen vacancies in the presence of these new microstructural features, and their future role in the design of future fast-ion conductors, is outlined.« less

  9. FAST OPENING SWITCH

    DOEpatents

    Bender, M.; Bennett, F.K.; Kuckes, A.F.

    1963-09-17

    A fast-acting electric switch is described for rapidly opening a circuit carrying large amounts of electrical power. A thin, conducting foil bridges a gap in this circuit and means are provided for producing a magnetic field and eddy currents in the foil, whereby the foil is rapidly broken to open the circuit across the gap. Advantageously the foil has a hole forming two narrow portions in the foil and the means producing the magnetic field and eddy currents comprises an annular coil having its annulus coaxial with the hole in the foil and turns adjacent the narrow portions of the foil. An electrical current flows through the coil to produce the magnetic field and eddy currents in the foil. (AEC)

  10. FAST NEUTRON SPECTROMETER

    DOEpatents

    Davis, F.J.; Hurst, G.S.; Reinhardt, P.W.

    1959-08-18

    An improved proton recoil spectrometer for determining the energy spectrum of a fast neutron beam is described. Instead of discriminating against and thereby"throwing away" the many recoil protons other than those traveling parallel to the neutron beam axis as do conventional spectrometers, this device utilizes protons scattered over a very wide solid angle. An ovoidal gas-filled recoil chamber is coated on the inside with a scintillator. The ovoidal shape of the sensitive portion of the wall defining the chamber conforms to the envelope of the range of the proton recoils from the radiator disposed within the chamber. A photomultiplier monitors the output of the scintillator, and a counter counts the pulses caused by protons of energy just sufficient to reach the scintillator.

  11. FAST ACTING CURRENT SWITCH

    DOEpatents

    Batzer, T.H.; Cummings, D.B.; Ryan, J.F.

    1962-05-22

    A high-current, fast-acting switch is designed for utilization as a crowbar switch in a high-current circuit such as used to generate the magnetic confinement field of a plasma-confining and heat device, e.g., Pyrotron. The device particularly comprises a cylindrical housing containing two stationary, cylindrical contacts between which a movable contact is bridged to close the switch. The movable contact is actuated by a differential-pressure, airdriven piston assembly also within the housing. To absorb the acceleration (and the shock imparted to the device by the rapidly driven, movable contact), an adjustable air buffer assembly is provided, integrally connected to the movable contact and piston assembly. Various safety locks and circuit-synchronizing means are also provided to permit proper cooperation of the invention and the high-current circuit in which it is installed. (AEC)

  12. Chemistry of fast electrons

    PubMed Central

    Maximoff, Sergey N.; Head-Gordon, Martin P.

    2009-01-01

    A chemicurrent is a flux of fast (kinetic energy ≳ 0.5−1.3 eV) metal electrons caused by moderately exothermic (1−3 eV) chemical reactions over high work function (4−6 eV) metal surfaces. In this report, the relation between chemicurrent and surface chemistry is elucidated with a combination of top-down phenomenology and bottom-up atomic-scale modeling. Examination of catalytic CO oxidation, an example which exhibits a chemicurrent, reveals 3 constituents of this relation: The localization of some conduction electrons to the surface via a reduction reaction, 0.5 O2 + δe− → Oδ− (Red); the delocalization of some surface electrons into a conduction band in an oxidation reaction, Oδ− + CO → CO2δ− → CO2 + δe− (Ox); and relaxation without charge transfer (Rel). Juxtaposition of Red, Ox, and Rel produces a daunting variety of metal electronic excitations, but only those that originate from CO2 reactive desorption are long-range and fast enough to dominate the chemicurrent. The chemicurrent yield depends on the universality class of the desorption process and the distribution of the desorption thresholds. This analysis implies a power-law relation with exponent 2.66 between the chemicurrent and the heat of adsorption, which is consistent with experimental findings for a range of systems. This picture also applies to other oxidation-reduction reactions over high work function metal surfaces. PMID:19561296

  13. Fast word reading in pure alexia: "fast, yet serial".

    PubMed

    Bormann, Tobias; Wolfer, Sascha; Hachmann, Wibke; Neubauer, Claudia; Konieczny, Lars

    2015-01-01

    Pure alexia is a severe impairment of word reading in which individuals process letters serially with a pronounced length effect. Yet, there is considerable variation in the performance of alexic readers with generally very slow, but also occasionally fast responses, an observation addressed rarely in previous reports. It has been suggested that "fast" responses in pure alexia reflect residual parallel letter processing or that they may even be subserved by an independent reading system. Four experiments assessed fast and slow reading in a participant (DN) with pure alexia. Two behavioral experiments investigated frequency, neighborhood, and length effects in forced fast reading. Two further experiments measured eye movements when DN was forced to read quickly, or could respond faster because words were easier to process. Taken together, there was little support for the proposal that "qualitatively different" mechanisms or reading strategies underlie both types of responses in DN. Instead, fast responses are argued to be generated by the same serial-reading strategy.

  14. Integrated simulation approach for laser-driven fast ignition.

    PubMed

    Wang, W-M; Gibbon, P; Sheng, Z-M; Li, Y-T

    2015-01-01

    An integrated simulation approach fully based on the particle-in-cell (PIC) model is proposed, which involves both fast-particle generation via laser solid-density plasma interaction and transport and energy deposition of the particles in extremely high-density plasma. It is realized by introducing two independent systems in a simulation, where the fast-particle generation is simulated by a full PIC system and the transport and energy deposition computed by a second PIC system with a reduced field solver. Data of the fast particles generated in the full PIC system are copied to the reduced PIC system in real time as the fast-particle source. Unlike a two-region approach, which takes a single PIC system and two field solvers in two plasma density regions, respectively, the present one need not match the field solvers since the reduced field solver and the full solver adopted respectively in the two systems are independent. A simulation case is presented, which demonstrates that this approach can be applied to integrated simulation of fast ignition with real target densities, e.g., 300 g/cm(3). PMID:25679717

  15. Fast pitch softball injuries.

    PubMed

    Meyers, M C; Brown, B R; Bloom, J A

    2001-01-01

    The popularity of fast pitch softball in the US and throughout the world is well documented. Along with this popularity, there has been a concomitant increase in the number of injuries. Nearly 52% of cases qualify as major disabling injuries requiring 3 weeks or more of treatment and 2% require surgery. Interestingly, 75% of injuries occur during away games and approximately 31% of traumas occur during nonpositional and conditioning drills. Injuries range from contusions and tendinitis to ligamentous disorders and fractures. Although head and neck traumas account for 4 to 12% of cases, upper extremity traumas account for 23 to 47% of all injuries and up to 19% of cases involve the knee. Approximately 34 to 42% of injuries occur when the athlete collides with another individual or object. Other factors involved include the quality of playing surface, athlete's age and experience level, and the excessive physical demands associated with the sport. Nearly 24% of injuries involve base running and are due to poor judgement, sliding technique, current stationary base design, unorthodox joint and extremity position during ground impact and catching of cleats. The increasing prevalence of overtraining syndrome among athletes has been attributed to an unclear definition of an optimal training zone, poor communication between player and coach, and the limited ability of bone and connective tissue to quickly respond to match the demands of the sport. This has led routinely to arm, shoulder and lumbar instability, chronic nonsteroidal anti-inflammatory drug (NSAID) use and time loss injuries in 45% of pitching staff during a single season. Specific attention to a safer playing environment, coaching and player education, and sport-specific training and conditioning would reduce the risk, rate and severity of fast pitch traumas. Padding of walls, backstops, rails and dugout areas, as well as minimising use of indoor facilities, is suggested to decrease the number of collision

  16. Fast pitch softball injuries.

    PubMed

    Meyers, M C; Brown, B R; Bloom, J A

    2001-01-01

    The popularity of fast pitch softball in the US and throughout the world is well documented. Along with this popularity, there has been a concomitant increase in the number of injuries. Nearly 52% of cases qualify as major disabling injuries requiring 3 weeks or more of treatment and 2% require surgery. Interestingly, 75% of injuries occur during away games and approximately 31% of traumas occur during nonpositional and conditioning drills. Injuries range from contusions and tendinitis to ligamentous disorders and fractures. Although head and neck traumas account for 4 to 12% of cases, upper extremity traumas account for 23 to 47% of all injuries and up to 19% of cases involve the knee. Approximately 34 to 42% of injuries occur when the athlete collides with another individual or object. Other factors involved include the quality of playing surface, athlete's age and experience level, and the excessive physical demands associated with the sport. Nearly 24% of injuries involve base running and are due to poor judgement, sliding technique, current stationary base design, unorthodox joint and extremity position during ground impact and catching of cleats. The increasing prevalence of overtraining syndrome among athletes has been attributed to an unclear definition of an optimal training zone, poor communication between player and coach, and the limited ability of bone and connective tissue to quickly respond to match the demands of the sport. This has led routinely to arm, shoulder and lumbar instability, chronic nonsteroidal anti-inflammatory drug (NSAID) use and time loss injuries in 45% of pitching staff during a single season. Specific attention to a safer playing environment, coaching and player education, and sport-specific training and conditioning would reduce the risk, rate and severity of fast pitch traumas. Padding of walls, backstops, rails and dugout areas, as well as minimising use of indoor facilities, is suggested to decrease the number of collision

  17. Fast ignition breakeven scaling.

    SciTech Connect

    Slutz, Stephen A.; Vesey, Roger Alan

    2005-01-01

    A series of numerical simulations have been performed to determine scaling laws for fast ignition break even of a hot spot formed by energetic particles created by a short pulse laser. Hot spot break even is defined to be when the fusion yield is equal to the total energy deposited in the hot spot through both the initial compression and the subsequent heating. In these simulations, only a small portion of a previously compressed mass of deuterium-tritium fuel is heated on a short time scale, i.e., the hot spot is tamped by the cold dense fuel which surrounds it. The hot spot tamping reduces the minimum energy required to obtain break even as compared to the situation where the entire fuel mass is heated, as was assumed in a previous study [S. A. Slutz, R. A. Vesey, I. Shoemaker, T. A. Mehlhorn, and K. Cochrane, Phys. Plasmas 7, 3483 (2004)]. The minimum energy required to obtain hot spot break even is given approximately by the scaling law E{sub T} = 7.5({rho}/100){sup -1.87} kJ for tamped hot spots, as compared to the previously reported scaling of E{sub UT} = 15.3({rho}/100){sup -1.5} kJ for untamped hotspots. The size of the compressed fuel mass and the focusability of the particles generated by the short pulse laser determines which scaling law to use for an experiment designed to achieve hot spot break even.

  18. Responder fast steering mirror

    NASA Astrophysics Data System (ADS)

    Bullard, Andrew; Shawki, Islam

    2013-10-01

    Raytheon Space and Airborne Systems (SAS) has designed, built and tested a 3.3-inch diameter fast steering mirror (FSM) for space application. This 2-axis FSM operates over a large angle (over 10 degree range), has a very high servo bandwidth (over 3.3 Khz closed loop bandwidth), has nanoradian-class noise, and is designed to support microradian class line of sight accuracy. The FSM maintains excellent performance over large temperature ranges (which includes wave front error) and has very high reliability with the help of fully redundant angle sensors and actuator circuits. The FSM is capable of achieving all its design requirements while also being reaction-compensated. The reaction compensation is achieved passively and does not need a separate control loop. The FSM has undergone various environmental testing which include exported forces and torques and thermal vacuum testing that support the FSM design claims. This paper presents the mechanical design and test results of the mechanism which satisfies the rigorous vacuum and space application requirements.

  19. Responder fast steering mirror

    NASA Astrophysics Data System (ADS)

    Bullard, Andrew; Shawki, Islam

    2013-09-01

    Raytheon Space and Airborne Systems (SAS) has designed, built and tested a 3.3-inch diameter fast steering mirror (FSM) for space application. This 2-axis FSM operates over a large angle (over 10 degree range), has a very high servo bandwidth (over 3.3 Khz closed loop bandwidth), has nanoradian-class noise, and is designed to support microradian class line of sight accuracy. The FSM maintains excellent performance over large temperature ranges (which includes wave front error) and has very high reliability with the help of fully redundant angle sensors and actuator circuits. The FSM is capable of achieving all its design requirements while also being reaction-compensated. The reaction compensation is achieved passively and does not need a separate control loop. The FSM has undergone various environmental testing which include exported forces and torques and thermal vacuum testing that support the FSM design claims. This paper presents the mechanical design and test results of the mechanism which satisfies the rigorous vacuum and space application requirements.

  20. Parallel fast gauss transform

    SciTech Connect

    Sampath, Rahul S; Sundar, Hari; Veerapaneni, Shravan

    2010-01-01

    We present fast adaptive parallel algorithms to compute the sum of N Gaussians at N points. Direct sequential computation of this sum would take O(N{sup 2}) time. The parallel time complexity estimates for our algorithms are O(N/n{sub p}) for uniform point distributions and O( (N/n{sub p}) log (N/n{sub p}) + n{sub p}log n{sub p}) for non-uniform distributions using n{sub p} CPUs. We incorporate a plane-wave representation of the Gaussian kernel which permits 'diagonal translation'. We use parallel octrees and a new scheme for translating the plane-waves to efficiently handle non-uniform distributions. Computing the transform to six-digit accuracy at 120 billion points took approximately 140 seconds using 4096 cores on the Jaguar supercomputer. Our implementation is 'kernel-independent' and can handle other 'Gaussian-type' kernels even when explicit analytic expression for the kernel is not known. These algorithms form a new class of core computational machinery for solving parabolic PDEs on massively parallel architectures.

  1. Fast Fuzzy Arithmetic Operations

    NASA Technical Reports Server (NTRS)

    Hampton, Michael; Kosheleva, Olga

    1997-01-01

    In engineering applications of fuzzy logic, the main goal is not to simulate the way the experts really think, but to come up with a good engineering solution that would (ideally) be better than the expert's control, In such applications, it makes perfect sense to restrict ourselves to simplified approximate expressions for membership functions. If we need to perform arithmetic operations with the resulting fuzzy numbers, then we can use simple and fast algorithms that are known for operations with simple membership functions. In other applications, especially the ones that are related to humanities, simulating experts is one of the main goals. In such applications, we must use membership functions that capture every nuance of the expert's opinion; these functions are therefore complicated, and fuzzy arithmetic operations with the corresponding fuzzy numbers become a computational problem. In this paper, we design a new algorithm for performing such operations. This algorithm is applicable in the case when negative logarithms - log(u(x)) of membership functions u(x) are convex, and reduces computation time from O(n(exp 2))to O(n log(n)) (where n is the number of points x at which we know the membership functions u(x)).

  2. Fasting of mice: a review.

    PubMed

    Jensen, T L; Kiersgaard, M K; Sørensen, D B; Mikkelsen, L F

    2013-10-01

    Fasting of mice is a common procedure performed in association with many different types of experiments mainly in order to reduce variability in investigatory parameters or to facilitate surgical procedures. However, the effects of fasting not directly related to the investigatory parameters are often ignored. The aim of this review is to present and summarize knowledge about the effects of fasting of mice to facilitate optimization of the fasting procedure for any given study and thereby maximize the scientific outcome and minimize the discomfort for the mice and hence ensure high animal welfare. The results are presented from a number of experimental studies, providing evidence for fasting-induced changes in hormone balance, body weight, metabolism, hepatic enzymes, cardiovascular parameters, body temperature and toxicological responses. A description of relevant normal behaviour and standard physiological parameters is given, concluding that mice are primarily nocturnal and consume two-thirds of their total food intake during the night. It is argued that overnight fasting of mice is not comparable with overnight fasting of humans because the mouse has a nocturnal circadian rhythm and a higher metabolic rate. It is suggested that because many physiological parameters are regulated by circadian rhythms, fasting initiated at different points in the circadian rhythm has different impacts and produces different results.

  3. Fast Feedback in Classroom Practice

    ERIC Educational Resources Information Center

    Emmett, Katrina; Klaassen, Kees; Eijkelhof, Harrie

    2009-01-01

    In this article we describe one application of the fast feedback method (see Berg 2003 "Aust. Sci. Teach. J." 28-34) in secondary mechanics education. Two teachers tried out a particular sequence twice, in consecutive years, once with and once without the use of fast feedback. We found the method to be successful, and the data that we obtained…

  4. Fast-Polynomial-Transform Program

    NASA Technical Reports Server (NTRS)

    Truong, T. K.; Hsu, I. S.; Chu, Y. F.

    1987-01-01

    Computer program uses fast-polynomial-transformation (FPT) algorithm applicable to two-dimensional mathematical convolutions. Two-dimensional cyclic convolutions converted to one-dimensional convolutions in polynomial rings. Program decomposes cyclic polynomials into polynomial convolutions of same length. Only FPT's and fast Fourier transforms of same length required. Modular approach saves computional resources. Program written in C.

  5. Impact of Including Higher Actinides in Fast Reactor Transmutation Analyses

    SciTech Connect

    B. Forget; M. Asgari; R. Ferrer; S. Bays

    2007-09-01

    Previous fast reactor transmutation studies generally disregarded higher mass minor actinides beyond Cm-246 due to various considerations including deficiencies in nuclear cross-section data. Although omission of these higher mass actinides does not significantly impact the neutronic calculations and fuel cycle performance parameters follow-on neutron dose calculations related to fuel recycling, transportation and handling are significantly impacted. This report shows that including the minor actinides in the equilibrium fast reactor calculations will increase the predicted neutron emission by about 30%. In addition a sensitivity study was initiated by comparing the impact of different cross-section evaluation file for representing these minor actinides.

  6. Radar system components to detect small and fast objects

    NASA Astrophysics Data System (ADS)

    Hülsmann, Axel; Zech, Christian; Klenner, Mathias; Tessmann, Axel; Leuther, Arnulf; Lopez-Diaz, Daniel; Schlechtweg, Michael; Ambacher, Oliver

    2015-05-01

    Small and fast objects, for example bullets of caliber 5 to 10 mm, fired from guns like AK-47, can cause serious problems to aircrafts in asymmetric warfare. Especially slow and big aircrafts, like heavy transport helicopters are an easy mark of small caliber hand fire weapons. These aircrafts produce so much noise, that the crew is not able to recognize an attack unless serious problems occur and important systems of the aircraft fail. This is just one of many scenarios, where the detection of fast and small objects is desirable. Another scenario is the collision of space debris particles with satellites.

  7. Transport Phenomena.

    ERIC Educational Resources Information Center

    McCready, Mark J.; Leighton, David T.

    1987-01-01

    Discusses the problems created in graduate chemical engineering programs when students enter with a wide diversity of understandings of transport phenomena. Describes a two-semester graduate transport course sequence at the University of Notre Dame which focuses on fluid mechanics and heat and mass transfer. (TW)

  8. Fast Ignition Experimental and Theoretical Studies

    SciTech Connect

    Akli, Kramer Ugerthen

    2006-01-01

    We are becoming dependent on energy more today than we were a century ago, and with increasing world population and booming economies, sooner or later our energy sources will be exhausted. Moreover, our economy and welfare strongly depends on foreign oil and in the shadow of political uncertainties, there is an urgent need for a reliable, safe, and cheap energy source. Thermonuclear fusion, if achieved, is that source of energy which not only will satisfy our demand for today but also for centuries to come. Today, there are two major approaches to achieve fusion: magnetic confinement fusion (MFE) and inertial confinement fusion (ICF). This dissertation explores the inertial confinement fusion using the fast ignition concept. Unlike the conventional approach where the same laser is used for compression and ignition, in fast ignition separate laser beams are used. This dissertation addresses three very important topics to fast ignition inertial confinement fusion. These are laser-to-electron coupling efficiency, laser-generated electron beam transport, and the associated isochoric heating. First, an integrated fast ignition experiment is carried out with 0.9 kJ of energy in the compression beam and 70 J in the ignition beam. Measurements of absolute Kα yield from the imploded core revealed that about 17% of the laser energy is coupled to the suprathermal electrons. Modeling of the transport of these electrons and the associated isochoric heating, with the previously determined laser-to-electron conversion efficiency, showed a maximum target temperature of 166 eV at the front where the electron flux is higher and the density is lower. The contribution of the potential, induced by charge separation, in opposing the motion of the electrons was moderate. Second, temperature sensitivity of Cu Kα imaging efficiency using a spherical Bragg reflecting crystal is investigated. It was found that due to the shifting and broadening of the K

  9. Anomalous Flattening of the Fast-Ion Profile during Alfvén-Eigenmode Activity

    NASA Astrophysics Data System (ADS)

    Heidbrink, W. W.; Gorelenkov, N. N.; Luo, Y.; van Zeeland, M. A.; White, R. B.; Austin, M. E.; Burrell, K. H.; Kramer, G. J.; Makowski, M. A.; McKee, G. R.; Nazikian, R.

    2007-12-01

    Neutral-beam injection into plasmas with negative central shear produces a rich spectrum of toroidicity-induced and reversed-shear Alfvén eigenmodes in the DIII-D tokamak. The first application of fast-ion Dα (FIDA) spectroscopy to Alfvén-eigenmode physics shows that the central fast-ion profile is anomalously flat in the inner half of the discharge. Neutron and equilibrium measurements corroborate the FIDA data. The current density driven by fast ions is also strongly modified. Calculations based on the measured mode amplitudes do not explain the observed fast-ion transport.

  10. Anomalous flattening of the fast-ion profile during Alfvén-Eigenmode activity.

    PubMed

    Heidbrink, W W; Gorelenkov, N N; Luo, Y; Van Zeeland, M A; White, R B; Austin, M E; Burrell, K H; Kramer, G J; Makowski, M A; McKee, G R; Nazikian, R

    2007-12-14

    Neutral-beam injection into plasmas with negative central shear produces a rich spectrum of toroidicity-induced and reversed-shear Alfvén eigenmodes in the DIII-D tokamak. The first application of fast-ion D_{alpha} (FIDA) spectroscopy to Alfvén-eigenmode physics shows that the central fast-ion profile is anomalously flat in the inner half of the discharge. Neutron and equilibrium measurements corroborate the FIDA data. The current density driven by fast ions is also strongly modified. Calculations based on the measured mode amplitudes do not explain the observed fast-ion transport.

  11. Anomalous Flattening of the Fast-Ion Profile during Alfven-Eigenmode Activity

    SciTech Connect

    Heidbrink, W. W.; Luo, Y.; Gorelenkov, N. N.; White, R. B.; Kramer, G. J.; Nazikian, R.; Van Zeeland, M. A.; Burrell, K. H.; Austin, M. E.; Makowski, M. A.; McKee, G. R.

    2007-12-14

    Neutral-beam injection into plasmas with negative central shear produces a rich spectrum of toroidicity-induced and reversed-shear Alfven eigenmodes in the DIII-D tokamak. The first application of fast-ion D{sub {alpha}} (FIDA) spectroscopy to Alfven-eigenmode physics shows that the central fast-ion profile is anomalously flat in the inner half of the discharge. Neutron and equilibrium measurements corroborate the FIDA data. The current density driven by fast ions is also strongly modified. Calculations based on the measured mode amplitudes do not explain the observed fast-ion transport.

  12. An enhanced fast scanning algorithm for image segmentation

    NASA Astrophysics Data System (ADS)

    Ismael, Ahmed Naser; Yusof, Yuhanis binti

    2015-12-01

    Segmentation is an essential and important process that separates an image into regions that have similar characteristics or features. This will transform the image for a better image analysis and evaluation. An important benefit of segmentation is the identification of region of interest in a particular image. Various algorithms have been proposed for image segmentation and this includes the Fast Scanning algorithm which has been employed on food, sport and medical images. It scans all pixels in the image and cluster each pixel according to the upper and left neighbor pixels. The clustering process in Fast Scanning algorithm is performed by merging pixels with similar neighbor based on an identified threshold. Such an approach will lead to a weak reliability and shape matching of the produced segments. This paper proposes an adaptive threshold function to be used in the clustering process of the Fast Scanning algorithm. This function used the gray'value in the image's pixels and variance Also, the level of the image that is more the threshold are converted into intensity values between 0 and 1, and other values are converted into intensity values zero. The proposed enhanced Fast Scanning algorithm is realized on images of the public and private transportation in Iraq. Evaluation is later made by comparing the produced images of proposed algorithm and the standard Fast Scanning algorithm. The results showed that proposed algorithm is faster in terms the time from standard fast scanning.

  13. Fast-ion D-alpha diagnostic for NSTX

    SciTech Connect

    Heidbrink, W. W.; Bell, R. E.; Luo, Y.; Solomon, W.

    2006-10-15

    A fast-ion D-alpha (FIDA) diagnostic is under development for the National Spherical Torus Experiment (NSTX). The FIDA technique is a charge-exchange recombination spectroscopy measurement that exploits the large Doppler shift of Balmer-alpha light from energetic hydrogenic atoms to infer the fast-ion density. The principal objective of the NSTX installation is to measure the transport of beam ions caused by fast-ion driven instabilities; detection of perpendicular acceleration of fast ions during high harmonic fast wave heating is another important goal. Recent data from a DIII-D FIDA diagnostic guide the design. The planned NSTX diagnostic consists of two separate instruments focusing on different aspects of the measurement. One instrument uses a transmission grating spectrometer to measure the perpendicular energy spectrum and the spatial profile every 10 ms; the anticipated resolution is {approx}10 keV in energy and {approx}5 cm in radius. A second instrument employs bandpass filters to detect fast-ion redistribution events with millisecond temporal resolution.

  14. A fast neighbor joining method.

    PubMed

    Li, J F

    2015-01-01

    With the rapid development of sequencing technologies, an increasing number of sequences are available for evolutionary tree reconstruction. Although neighbor joining is regarded as the most popular and fastest evolutionary tree reconstruction method [its time complexity is O(n(3)), where n is the number of sequences], it is not sufficiently fast to infer evolutionary trees containing more than a few hundred sequences. To increase the speed of neighbor joining, we herein propose FastNJ, a fast implementation of neighbor joining, which was motivated by RNJ and FastJoin, two improved versions of conventional neighbor joining. The main difference between FastNJ and conventional neighbor joining is that, in the former, many pairs of nodes selected by the rule used in RNJ are joined in each iteration. In theory, the time complexity of FastNJ can reach O(n(2)) in the best cases. Experimental results show that FastNJ yields a significant increase in speed compared to RNJ and conventional neighbor joining with a minimal loss of accuracy. PMID:26345805

  15. Optimal shortcuts for atomic transport in anharmonic traps

    NASA Astrophysics Data System (ADS)

    Zhang, Qi; Muga, J. G.; Guéry-Odelin, D.; Chen, Xi

    2016-06-01

    We design fast trap trajectories to transport cold atoms in anharmonic traps, combining invariant-based inverse engineering, perturbation theory, and optimal control theory. Among the ideal trajectories for harmonic traps, we choose the ones that minimize the anharmonic energy.

  16. Fundamental Aspects of Ion Transport in Solid Electrolytes

    NASA Technical Reports Server (NTRS)

    Ratnakumar, B. V.; Narayanan, S. R.

    1994-01-01

    Solid electrolytes (also termed as superionic solids or fast ion conductors) are characterized by high electrical conductivity, comparable to concentrated liquid electrolytes or even molten salt electrolytes, made possible by rapid transport of ions in the crystalline lattice.

  17. Fast ion beta limit measurements by collimated neutron detection in MST plasmas

    NASA Astrophysics Data System (ADS)

    Capecchi, William; Anderson, Jay; Bonofiglo, Phillip; Kim, Jungha; Sears, Stephanie

    2015-11-01

    Fast ion orbits in the reversed field pinch (RFP) are well ordered and classically confined despite magnetic field stochasticity generated by multiple tearing modes. Classical TRANSP modeling of a 1MW tangentially injected hydrogen neutral beam in MST deuterium plasmas predicts a core-localized fast ion density that can be up to 25% of the electron density and a fast ion beta of many times the local thermal beta. However, neutral particle analysis of an NBI-driven mode (presumably driven by a fast ion pressure gradient) shows mode-induced transport of core-localized fast ions and a saturated fast ion density. The TRANSP modeling is presumed valid until the onset of the beam-driven mode and gives an initial estimate of the volume-averaged fast ion beta of 1-2% (local core value up to 10%). A collimated neutron detector for fusion product profile measurements will be used to determine the spatial distribution of fast ions, allowing for a first measurement of the critical fast-ion pressure gradient required for mode destabilization. Testing/calibration data and initial fast-ion profiles will be presented. Characterization of both the local and global fast ion beta will be done for deuterium beam injection into deuterium plasmas for comparison to TRANSP predictions. Work supported by US DOE.

  18. Transportation of medical isotopes

    SciTech Connect

    Nielsen, D.L.

    1997-11-19

    A Draft Technical Information Document (HNF-1855) is being prepared to evaluate proposed interim tritium and medical isotope production at the Fast Flux Test Facility (FFTF). This assessment examines the potential health and safety impacts of transportation operations associated with the production of medical isotopes. Incident-free and accidental impacts are assessed using bounding source terms for the shipment of nonradiological target materials to the Hanford Site, the shipment of irradiated targets from the FFTF to the 325 Building, and the shipment of medical isotope products from the 325 Building to medical distributors. The health and safety consequences to workers and the public from the incident-free transportation of targets and isotope products would be within acceptable levels. For transportation accidents, risks to works and the public also would be within acceptable levels. This assessment is based on best information available at this time. As the medical isotope program matures, this analysis will be revised, if necessary, to support development of a final revision to the Technical Information Document.

  19. Intercellular transport.

    PubMed

    Thatcher, Jack D

    2013-04-16

    These animations depict generalities of intercellular transport. The animation called "permeability and transport" demonstrates the permeability of four classes of molecules. The "gap junctions" animation shows how these intercellular complexes exclude large factors while they allow small factors to diffuse between cells. These animations serve as useful resources for any collegiate-level course that describes these processes. Courses that might use them include biochemistry, biophysics, cell biology, introductory biology, and physiology.

  20. NASA AVOSS Fast-Time Wake Prediction Models: User's Guide

    NASA Technical Reports Server (NTRS)

    Ahmad, Nash'at N.; VanValkenburg, Randal L.; Pruis, Matthew

    2014-01-01

    The National Aeronautics and Space Administration (NASA) is developing and testing fast-time wake transport and decay models to safely enhance the capacity of the National Airspace System (NAS). The fast-time wake models are empirical algorithms used for real-time predictions of wake transport and decay based on aircraft parameters and ambient weather conditions. The aircraft dependent parameters include the initial vortex descent velocity and the vortex pair separation distance. The atmospheric initial conditions include vertical profiles of temperature or potential temperature, eddy dissipation rate, and crosswind. The current distribution includes the latest versions of the APA (3.4) and the TDP (2.1) models. This User's Guide provides detailed information on the model inputs, file formats, and the model output. An example of a model run and a brief description of the Memphis 1995 Wake Vortex Dataset is also provided.

  1. Fast Access Data Acquisition System

    SciTech Connect

    Dr. Vladimir Katsman

    1998-03-17

    Our goal in this program is to develop Fast Access Data Acquisition System (FADAS) by combining the flexibility of Multilink's GaAs and InP electronics and electro-optics with an extremely high data rate for the efficient handling and transfer of collider experimental data. This novel solution is based on Multilink's and Los Alamos National Laboratory's (LANL) unique components and technologies for extremely fast data transfer, storage, and processing.

  2. Fast analysis of radionuclide decay chain migration

    NASA Astrophysics Data System (ADS)

    Chen, J. S.; Liang, C. P.; Liu, C. W.; Li, L.

    2014-12-01

    A novel tool for rapidly predicting the long-term plume behavior of an arbitrary length radionuclide decay chain is presented in this study. This fast tool is achieved based on generalized analytical solutions in compact format derived for a set of two-dimensional advection-dispersion equations coupled with sequential first-order decay reactions in groundwater system. The performance of the developed tool is evaluated by a numerical model using a Laplace transform finite difference scheme. The results of performance evaluation indicate that the developed model is robust and accurate. The developed model is then used to fast understand the transport behavior of a four-member radionuclide decay chain. Results show that the plume extents and concentration levels of any target radionuclide are very sensitive to longitudinal, transverse dispersion, decay rate constant and retardation factor. The developed model are useful tools for rapidly assessing the ecological and environmental impact of the accidental radionuclide releases such as the Fukushima nuclear disaster where multiple radionuclides leaked through the reactor, subsequently contaminating the local groundwater and ocean seawater in the vicinity of the nuclear plant.

  3. Psychophysiological study on fasting therapy.

    PubMed

    Yamamoto, H; Suzuki, J; Yamauchi, Y

    1979-01-01

    The Tohoku University method of fasting therapy was performed on 380 patients. The clinical results revealed an efficacy rate of 87%. With regard to psychosomatic diseases, irritable colon syndrome, neurocirculatory asthenia, mild diabetes mellitus, obesity and borderline hypertension were good indications for this therapy. In order to clarify the therapeutic mechanism, several clinical examinations were administered before, during and after therapy. EEG data was analysed according to the power spectral method. The peak frequency decreased as fasting progressed, while it increased as re-fed continued. Percent energy of alpha waves after fasting therapy was significantly higher than that of the pre-fasting stage. The dexamethasone suppression rate of urine 17-OHCS after fasting therapy was significantly lower than that of the pre-fasting stage. It seems that ketone nutrition may work as a strong stressor in the brain cell, temporarily placing all biological mechanisms in a stress state and then activating the natural healing power inherent to the human body, thereby bringing about homeostasis.

  4. Electronic excitations in fast ion-solid collisions

    SciTech Connect

    Burgdoerfer, J. . Dept. of Physics and Astronomy Oak Ridge National Lab., TN )

    1990-01-01

    We review recent developments in the study of electronic excitation of projectiles in fast ion-solid collisions. Our focus will be primarily on theory but experimental advances will also be discussed. Topics include the evidence for velocity-dependent thresholds for the existence of bound states, wake-field effects on excited states, the electronic excitation of channeled projectiles, transport phenomena, and the interaction of highly charged ions with surfaces. 44 refs., 14 figs.

  5. New fast spectral analysis method for solid materials

    NASA Astrophysics Data System (ADS)

    Bel'Kov, M. V.; Burakov, V. S.; Kiris, V. V.; Raikov, S. N.

    2007-05-01

    We propose a new fast method for direct spectral analysis of solid materials based on laser ablation of the sample in deionized water and real-time transport of the aqueous suspension of nanoparticles into the inductively coupled plasma of an emission spectrometer. As a result, we have all the instrumental and methodological advantages of standard equipment, along with calibration of the spectrometer using standard aqueous solutions.

  6. Impact of nuclear data on fast neutron therapy

    SciTech Connect

    Hartmann Siantar, C.L.; Chandler, W.P.; Rathkopf, J.A.; Resler, D.A.; Cox, L.J.; Chadwick, M.B.; White, R.M.

    1994-05-12

    By combining a new, all-particle Monte Carlo radiation transport code, PEREGRINE, with the Lawrence Livermore National Laboratory (LLNL) nuclear data base, we have studied the importance of various neutron reactions on dose distributions in biological materials. Monte Carlo calculations have been performed for 5--20 MeV neutron pencil beams incident on biologically relevant materials arranged in several simple geometries. Results highlight the importance of nuclear data used for calculating dose distributions resulting from fast neutron therapy.

  7. Computational methods in tokamak transport

    SciTech Connect

    Houlberg, W.A.; Attenberger, S.E.; Lao, L.L.

    1982-06-01

    A variety of numerical methods for solving the time-dependent fluid transport equations for tokamak plasmas is presented. Among the problems discussed are techniques for solving the sometimes very stiff parabolic equations for particle and energy flow, treating convection-dominated energy transport that leads to large cell Reynolds numbers, optimizing the flow of a code to reduce the time spent updating the particle and energy source terms, coupling the one-dimensional (1-D) flux-surface-averaged fluid transport equations to solutions of the 2-D Grad-Shafranov equation for the plasma geometry, handling extremely fast transient problems such as internal MHD disruptions and pellet injection, and processing the output to summarize the physics parameters over the potential operating regime for reactors. Emphasis is placed on computational efficiency in both computer time and storage requirements.

  8. Dynamic Transportation Navigation

    NASA Astrophysics Data System (ADS)

    Meng, Xiaofeng; Chen, Jidong

    Miniaturization of computing devices, and advances in wireless communication and sensor technology are some of the forces that are propagating computing from the stationary desktop to the mobile outdoors. Some important classes of new applications that will be enabled by this revolutionary development include intelligent traffic management, location-based services, tourist services, mobile electronic commerce, and digital battlefield. Some existing application classes that will benefit from the development include transportation and air traffic control, weather forecasting, emergency response, mobile resource management, and mobile workforce. Location management, i.e., the management of transient location information, is an enabling technology for all these applications. In this chapter, we present the applications of moving objects management and their functionalities, in particular, the application of dynamic traffic navigation, which is a challenge due to the highly variable traffic state and the requirement of fast, on-line computations.

  9. Fast Poisson, Fast Helmholtz and fast linear elastostatic solvers on rectangular parallelepipeds

    SciTech Connect

    Wiegmann, A.

    1999-06-01

    FFT-based fast Poisson and fast Helmholtz solvers on rectangular parallelepipeds for periodic boundary conditions in one-, two and three space dimensions can also be used to solve Dirichlet and Neumann boundary value problems. For non-zero boundary conditions, this is the special, grid-aligned case of jump corrections used in the Explicit Jump Immersed Interface method. Fast elastostatic solvers for periodic boundary conditions in two and three dimensions can also be based on the FFT. From the periodic solvers we derive fast solvers for the new 'normal' boundary conditions and essential boundary conditions on rectangular parallelepipeds. The periodic case allows a simple proof of existence and uniqueness of the solutions to the discretization of normal boundary conditions. Numerical examples demonstrate the efficiency of the fast elastostatic solvers for non-periodic boundary conditions. More importantly, the fast solvers on rectangular parallelepipeds can be used together with the Immersed Interface Method to solve problems on non-rectangular domains with general boundary conditions. Details of this are reported in the preprint The Explicit Jump Immersed Interface Method for 2D Linear Elastostatics by the author.

  10. Effect of endurance training on glucose transport capacity and glucose transporter expression in rat skeletal muscle

    SciTech Connect

    Ploug, T.; Stallknecht, B.M.; Pedersen, O.; Kahn, B.B.; Ohkuwa, T.; Vinten, J.; Galbo, H. )

    1990-12-01

    The effect of 10 wk endurance swim training on 3-O-methylglucose (3-MG) uptake (at 40 mM 3-MG) in skeletal muscle was studied in the perfused rat hindquarter. Training resulted in an increase of approximately 33% for maximum insulin-stimulated 3-MG transport in fast-twitch red fibers and an increase of approximately 33% for contraction-stimulated transport in slow-twitch red fibers compared with nonexercised sedentary muscle. A fully additive effect of insulin and contractions was observed both in trained and untrained muscle. Compared with transport in control rats subjected to an almost exhaustive single exercise session the day before experiment both maximum insulin- and contraction-stimulated transport rates were increased in all muscle types in trained rats. Accordingly, the increased glucose transport capacity in trained muscle was not due to a residual effect of the last training session. Half-times for reversal of contraction-induced glucose transport were similar in trained and untrained muscles. The concentrations of mRNA for GLUT-1 (the erythrocyte-brain-Hep G2 glucose transporter) and GLUT-4 (the adipocyte-muscle glucose transporter) were increased approximately twofold by training in fast-twitch red muscle fibers. In parallel to this, Western blot demonstrated a approximately 47% increase in GLUT-1 protein and a approximately 31% increase in GLUT-4 protein. This indicates that the increases in maximum velocity for 3-MG transport in trained muscle is due to an increased number of glucose transporters.

  11. Smaller, Lower-Power Fast-Neutron Scintillation Detectors

    NASA Technical Reports Server (NTRS)

    Patel, Jagdish; Blaes, Brent

    2008-01-01

    Scintillation-based fast-neutron detectors that are smaller and less power-hungry than mainstream scintillation-based fast-neutron detectors are undergoing development. There are numerous applications for such detectors in monitoring fast-neutron fluxes from nuclear reactors, nuclear materials, and natural sources, both on Earth and in outer space. A particularly important terrestrial application for small, low-power, portable fast-neutron detectors lies in the requirement to scan for nuclear materials in cargo and baggage arriving at international transportation facilities. The present development of miniature, low-power scintillation-based fast-neutron detectors exploits recent advances in the fabrication of avalanche photodiodes (APDs). Basically, such a detector includes a plastic scintillator, typically between 300 and 400 m thick with very thin silver mirror coating on all its faces except the one bonded to an APD. All photons generated from scintillation are thus internally reflected and eventually directed to the APD. This design affords not only compactness but also tight optical coupling for utilization of a relatively large proportion of the scintillation light. The combination of this tight coupling and the avalanche-multiplication gain (typically between 750 and 1,000) of the APD is expected to have enough sensitivity to enable monitoring of a fast-neutron flux as small as 1,000 cm(exp -2)s(exp -1). Moreover, pulse-height analysis can be expected to provide information on the kinetic energies of incident neutrons. It has been estimated that a complete, fully developed fast-neutron detector of this type, would be characterized by linear dimensions of the order of 10 cm or less, a mass of no more than about 0.5 kg, and a power demand of no more than a few watts.

  12. HI Intensity Mapping with FAST

    NASA Astrophysics Data System (ADS)

    Bigot-Sazy, M.-A.; Ma, Y.-Z.; Battye, R. A.; Browne, I. W. A.; Chen, T.; Dickinson, C.; Harper, S.; Maffei, B.; Olivari, L. C.; Wilkinsondagger, P. N.

    2016-02-01

    We discuss the detectability of large-scale HI intensity fluctuations using the FAST telescope. We present forecasts for the accuracy of measuring the Baryonic Acoustic Oscillations and constraining the properties of dark energy. The FAST 19-beam L-band receivers (1.05-1.45 GHz) can provide constraints on the matter power spectrum and dark energy equation of state parameters (w0,wa) that are comparable to the BINGO and CHIME experiments. For one year of integration time we find that the optimal survey area is 6000 deg2. However, observing with larger frequency coverage at higher redshift (0.95-1.35 GHz) improves the projected errorbars on the HI power spectrum by more than 2 σ confidence level. The combined constraints from FAST, CHIME, BINGO and Planck CMB observations can provide reliable, stringent constraints on the dark energy equation of state.

  13. Fast reactors and nuclear nonproliferation

    SciTech Connect

    Avrorin, E.N.; Rachkov, V.I.; Chebeskov, A.N.

    2013-07-01

    Problems are discussed with regard to nuclear fuel cycle resistance in fast reactors to nuclear proliferation risk due to the potential for use in military programs of the knowledge, technologies and materials gained from peaceful nuclear power applications. Advantages are addressed for fast reactors in the creation of a more reliable mode of nonproliferation in the closed nuclear fuel cycle in comparison with the existing fully open and partially closed fuel cycles of thermal reactors. Advantages and shortcomings are also discussed from the point of view of nonproliferation from the start with fast reactors using plutonium of thermal reactor spent fuel and enriched uranium fuel to the gradual transition using their own plutonium as fuel. (authors)

  14. Future Assets, Student Talent (FAST)

    NASA Technical Reports Server (NTRS)

    1992-01-01

    Future Assets, Student Talent (FAST) motivates and prepares talented students with disabilities to further their education and achieve High Tech and professional employment. The FAST program is managed by local professionals, business, and industry leaders; it is modeled after High School High Tech project TAKE CHARGE started in Los Angeles in 1983. Through cooperative efforts of Alabama Department of Education, Vocational Rehabilitation, Adult and Children Services, and the President's Committee on Employment of People with Disabilities, north central Alabama was chosen as the second site for a High School High Tech project. In 1986 local business, industry, education, government agencies, and rehabilitation representatives started FAST. The program objectives and goals, results and accomplishments, and survey results are included.

  15. Pupil Transportation.

    ERIC Educational Resources Information Center

    Bete, Tim, Ed.

    1998-01-01

    Presents the opinions of four transportation experts on issues related to school buses. The experts respond to the following questions: will advertisements placed on buses be used to generate district revenue; will compressed natural gas or liquefied natural gas become standard fuel for school buses; and will school bus seat belts be mandatory and…

  16. Membrane Transport

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The selective movement and redistribution of ions and small organic molecules is essential for plant growth and cellular homeostasis. Because of this, plants have evolved numerous proteins that facilitate the transport of minerals, sugars, metabolites, and other compounds through the limiting membra...

  17. [Preoperative fasting guidelines: an update].

    PubMed

    López Muñoz, A C; Busto Aguirreurreta, N; Tomás Braulio, J

    2015-03-01

    Anesthesiology societies have issued various guidelines on preoperative fasting since 1990, not only to decrease the incidence of lung aspiration and anesthetic morbidity, but also to increase patient comfort prior to anesthesia. Some of these societies have been updating their guidelines, as such that, since 2010, we now have 2 evidence-based preoperative fasting guidelines available. In this article, an attempt is made to review these updated guidelines, as well as the current instructions for more controversial patients such as infants, the obese, and a particular type of ophthalmic surgery.

  18. Fast generation of stereolithographic models.

    PubMed

    Raic, K; Jansen, T; von Rymon-Lipinski, B; Tille, C; Seitz, H; Keeve, E

    2002-01-01

    In this paper we present a work-in-progress method for fast and efficient generation of stereolithographic models. The overall approach is embedded in our general software framework Julius, which runs on high-end-graphic systems as well as on low-level PCs. The design of the support structures needed for the stereolithographic process will allow semiautomatic generation of the model. We did produce support structures for stereolithographic models with this fast data processing pipeline and will show future perspectives in this paper. PMID:12451779

  19. Kinetics of ion transport through supramolecular channels in single crystals.

    PubMed

    Assouma, Cyrille D; Crochet, Aurélien; Chérémond, Yvens; Giese, Bernd; Fromm, Katharina M

    2013-04-22

    Single-crystal to single-crystal transformations are possible by ion-exchange and transport reactions through supramolecular channels that are composed of crown ether molecules and use trihalide ions as scaffolds. Kinetic measurements of ion transport at different temperatures provide activation energy data and show that a very fast exchange of K(+) ions with Na(+) ions occurs.

  20. Studies of thunderstorm transport processes with aircraft using tracer techniques

    SciTech Connect

    Detwiler, A.G.; Smith, P.L.; Stith, J.L.

    1996-10-01

    Instrumented aircraft can provide in situ measurements of winds and turbulence useful for studying transport and dispersion in clouds. Using inert artificial gases as tracers, and fast response analyzers on aircraft, time-resolved observations of transport and dispersion have been obtained. Examples are shown of these types of observations in and around cumulus and cumulonimbus clouds. 23 refs., 6 figs.

  1. Analysis of colloid transport

    SciTech Connect

    Travis, B.J.; Nuttall, H.E.

    1985-12-31

    The population balance methodology is described and applied to the transport and capture of polydispersed colloids in packed columns. The transient model includes particle growth, capture, convective transport, and dispersion. We also follow the dynamic accumulation of captured colloids on the solids. The multidimensional parabolic partial differential equation was solved by a recently enhanced method of characteristics technique. This computational technique minimized numerical dispersion and is computationally very fast. The FORTRAN 77 code ran on a VAX-780 in less than a minute and also runs on an IBM-AT using the Professional FORTRAN compiler. The code was extensively tested against various simplified cases and against analytical models. The packed column experiments by Saltelli et al. were re-analyzed incorporating the experimentally reported size distribution of the colloid feed material. Colloid capture was modeled using a linear size dependent filtration function. The effects of a colloid size dependent filtration factor and various initial colloid size distributions on colloid migration and capture were investigated. Also, we followed the changing colloid size distribution as a function of position in the column. Some simple arguments are made to assess the likelihood of colloid migration at a potential NTS Yucca Mountain waste disposal site. 10 refs., 3 figs., 1 tab.

  2. Fast-response cloud chamber

    NASA Technical Reports Server (NTRS)

    Fogal, G. L.

    1977-01-01

    Wall structure keeps chambers at constant, uniform temperature, yet allows them to be cooled rapidly if necessary. Wall structure, used in fast-response cloud chamber, has surface heater and coolant shell separated by foam insulation. It is lightweight and requires relatively little power.

  3. Fast Detector Simulation Using Lelaps

    SciTech Connect

    Langeveld, W

    2004-08-20

    Lelaps is a fast detector simulation program which reads StdHep generator files and produces SIO or LCIO output files. It swims particles through detectors taking into account magnetic fields, multiple scattering and dE/dx energy loss. It simulates parameterized showers in EM and hadronic calorimeters and supports gamma conversions and decays.

  4. Fast Facts 26-42.

    ERIC Educational Resources Information Center

    Florida State Board of Community Colleges, Tallahassee.

    The document is a compilation of Fast Facts on a wide range of issues affecting the Florida Community College System (FCCS) and higher education in general. It uses data extracted from a federal publication entitled "Answers in the Tool Box." Some of the topics that are addressed are as follows: important variables for student baccalaureate…

  5. Fast and Easy Website Tuneups

    ERIC Educational Resources Information Center

    Wisniewski, Jeff

    2008-01-01

    This article presents fast, easy and helpful hints for making web sites that people will want to use over and over again. These tips include: (1) Making sure that the website's copyright statement is up-to-date; (2) Adding "last updated" code to each webpage at the site; (3) Adding photos to the site's contact information; (4) Turning boring old…

  6. Fast Atom Bombardment Mass Spectrometry.

    ERIC Educational Resources Information Center

    Rinehart, Kenneth L., Jr.

    1982-01-01

    Discusses reactions and characteristics of fast atom bombardment (FAB) mass spectroscopy in which samples are ionized in a condensed state by bombardment with xenon or argon atoms, yielding positive/negative secondary ions. Includes applications of FAB to structural problems and considers future developments using the technique. (Author/JN)

  7. LNG transportation

    SciTech Connect

    Picard, J.

    1988-01-01

    In the beginning of 1965, the participants to the starting up of first French LNG transportation system between ARZEW and LE HAVRE were indeed pioneers when they started the cool-down of the three tanks of LE HAVRE, with a LNG freight delivered by old liberty-ship ''BEAUVAIS''. Could they forecast the development of LNG industry in FRANCE and in the world and imagine that modest 'JULES VERNE' and his two english brothers would have, 25 years later, 80 successors - more than five times as big, for the main part of them, that 12 liquefaction plants would be running in the world, supplying about twenty LNG terminals. For the first time, a country - FRANCE - can draw the lessons from the exploitation of the 3 LNG transportation systems during a long period. That is the subject of the present paper.

  8. Maintenance of skeletal muscle energy homeostasis during prolonged wintertime fasting in the raccoon dog (Nyctereutes procyonoides).

    PubMed

    Kinnunen, Sanni; Mänttäri, Satu; Herzig, Karl-Heinz; Nieminen, Petteri; Mustonen, Anne-Mari; Saarela, Seppo

    2015-05-01

    The raccoon dog (Nyctereutes procyonoides) is a canid species with autumnal fattening and prolonged wintertime fasting. Nonpathological body weight cycling and the ability to tolerate food deficiency make this species a unique subject for studying physiological mechanisms in energy metabolism. AMP-activated protein kinase (AMPK) is a cellular energy sensor regulating energy homeostasis. During acute fasting, AMPK promotes fatty acid oxidation and enhances glucose uptake. We evaluated the effects of prolonged fasting on muscle energy metabolism in farm-bred raccoon dogs. Total and phosphorylated AMPK and acetyl-CoA carboxylase (ACC), glucose transporter 4 (GLUT 4), insulin receptor and protein kinase B (Akt) protein expressions of hind limb muscles were determined by Western blot after 10 weeks of fasting. Plasma insulin, leptin, ghrelin, glucose and free fatty acid levels were measured, and muscle myosin heavy chain (MHC) isoform composition analyzed. Fasting had no effects on AMPK phosphorylation, but total AMPK expression decreased in m. rectus femoris, m. tibialis anterior and m. extensor digitorum longus resulting in a higher phosphorylation ratio. Decreased total expression was also observed for ACC. Fasting did not influence GLUT 4, insulin receptor or Akt expression, but Akt phosphorylation was lower in m. flexor digitorum superficialis and m. extensor digitorum longus. Three MHC isoforms (I, IIa and IIx) were detected without differences in composition between the fasted and control animals. The studied muscles were resistant to prolonged fasting indicating that raccoon dogs have an effective molecular regulatory system for preserving skeletal muscle function during wintertime immobility and fasting.

  9. ADVANCED CUTTINGS TRANSPORT STUDY

    SciTech Connect

    Stefan Miska; Nicholas Takach; Kaveh Ashenayi; Mengjiao Yu; Ramadan Ahmed; Mark Pickell; Len Volk; Lei Zhou; Zhu Chen; Aimee Washington; Crystal Redden

    2003-09-30

    The Quarter began with installing the new drill pipe, hooking up the new hydraulic power unit, completing the pipe rotation system (Task 4 has been completed), and making the SWACO choke operational. Detailed design and procurement work is proceeding on a system to elevate the drill-string section. The prototype Foam Generator Cell has been completed by Temco and delivered. Work is currently underway to calibrate the system. Literature review and preliminary model development for cuttings transportation with polymer foam under EPET conditions are in progress. Preparations for preliminary cuttings transport experiments with polymer foam have been completed. Two nuclear densitometers were re-calibrated. Drill pipe rotation system was tested up to 250 RPM. Water flow tests were conducted while rotating the drill pipe up to 100 RPM. The accuracy of weight measurements for cuttings in the annulus was evaluated. Additional modifications of the cuttings collection system are being considered in order to obtain the desired accurate measurement of cuttings weight in the annular test section. Cutting transport experiments with aerated fluids are being conducted at EPET, and analyses of the collected data are in progress. The printed circuit board is functioning with acceptable noise level to measure cuttings concentration at static condition using ultrasonic method. We were able to conduct several tests using a standard low pass filter to eliminate high frequency noise. We tested to verify that we can distinguish between different depths of sand in a static bed of sand. We tested with water, air and a mix of the two mediums. Major modifications to the DTF have almost been completed. A stop-flow cell is being designed for the DTF, the ACTF and Foam Generator/Viscometer which will allow us to capture bubble images without the need for ultra fast shutter speeds or microsecond flash system.

  10. Copper transport.

    PubMed

    Linder, M C; Wooten, L; Cerveza, P; Cotton, S; Shulze, R; Lomeli, N

    1998-05-01

    In adult humans, the net absorption of dietary copper is approximately 1 mg/d. Dietary copper joins some 4-5 mg of endogenous copper flowing into the gastrointestinal tract through various digestive juices. Most of this copper returns to the circulation and to the tissues (including liver) that formed them. Much lower amounts of copper flow into and out of other major parts of the body (including heart, skeletal muscle, and brain). Newly absorbed copper is transported to body tissues in two phases, borne primarily by plasma protein carriers (albumin, transcuprein, and ceruloplasmin). In the first phase, copper goes from the intestine to the liver and kidney; in the second phase, copper usually goes from the liver (and perhaps also the kidney) to other organs. Ceruloplasmin plays a role in this second phase. Alternatively, liver copper can also exit via the bile, and in a form that is less easily reabsorbed. Copper is also present in and transported by other body fluids, including those bathing the brain and central nervous system and surrounding the fetus in the amniotic sac. Ceruloplasmin is present in these fluids and may also be involved in copper transport there. The concentrations of copper and ceruloplasmin in milk vary with lactational stage. Parallel changes occur in ceruloplasmin messenger RNA expression in the mammary gland (as determined in pigs). Copper in milk ceruloplasmin appears to be particularly available for absorption, at least in rats. PMID:9587137

  11. Copper transport.

    PubMed

    Linder, M C; Wooten, L; Cerveza, P; Cotton, S; Shulze, R; Lomeli, N

    1998-05-01

    In adult humans, the net absorption of dietary copper is approximately 1 mg/d. Dietary copper joins some 4-5 mg of endogenous copper flowing into the gastrointestinal tract through various digestive juices. Most of this copper returns to the circulation and to the tissues (including liver) that formed them. Much lower amounts of copper flow into and out of other major parts of the body (including heart, skeletal muscle, and brain). Newly absorbed copper is transported to body tissues in two phases, borne primarily by plasma protein carriers (albumin, transcuprein, and ceruloplasmin). In the first phase, copper goes from the intestine to the liver and kidney; in the second phase, copper usually goes from the liver (and perhaps also the kidney) to other organs. Ceruloplasmin plays a role in this second phase. Alternatively, liver copper can also exit via the bile, and in a form that is less easily reabsorbed. Copper is also present in and transported by other body fluids, including those bathing the brain and central nervous system and surrounding the fetus in the amniotic sac. Ceruloplasmin is present in these fluids and may also be involved in copper transport there. The concentrations of copper and ceruloplasmin in milk vary with lactational stage. Parallel changes occur in ceruloplasmin messenger RNA expression in the mammary gland (as determined in pigs). Copper in milk ceruloplasmin appears to be particularly available for absorption, at least in rats.

  12. Fast Neutron Sensitivity with HPGe

    SciTech Connect

    Seifert, Allen; Hensley, Walter K.; Siciliano, Edward R.; Pitts, W. K.

    2008-01-22

    In addition to being excellent gamma-ray detectors, germanium detectors are also sensitive to fast neutrons. Incident neutrons undergo inelastic scattering {Ge(n,n')Ge*} off germanium nuclei and the resulting excited states emit gamma rays or conversion electrons. The response of a standard 140% high-purity germanium (HPGe) detector with a bismuth germanate (BGO) anti-coincidence shield was measured for several neutron sources to characterize the ability of the HPGe detector to detect fast neutrons. For a sensitivity calculation performed using the characteristic fast neutron response peak that occurs at 692 keV, the 140% germanium detector system exhibited a sensitivity of ~175 counts / kg of WGPumetal in 1000 seconds at a source-detector distance of 1 meter with 4 in. of lead shielding between source and detector. Theoretical work also indicates that it might be possible to use the shape of the fast-neutron inelastic scattering signatures (specifically, the end-point energy of the long high energy tail of the resulting asymmetric peak) to gain additional information about the energy distribution of the incident neutron spectrum. However, the experimentally observed end-point energies appear to be almost identical for each of the fast neutron sources counted. Detailed MCNP calculations show that the neutron energy distributions impingent on the detector for these sources are very similar in this experimental configuration, due to neutron scattering in a lead shield (placed between the neutron source and HPGe detector to reduce the gamma ray flux), the BGO anti-coincidence detector, and the concrete floor.

  13. Kinetic transport simulation of energetic particles

    NASA Astrophysics Data System (ADS)

    Sheng, He; Waltz, R. E.

    2016-05-01

    A kinetic transport code (EPtran) is developed for the transport of the energetic particles (EPs). The EPtran code evolves the EP distribution function in radius, energy, and pitch angle phase space (r, E, λ) to steady state with classical slowing down, pitch angle scattering, as well as radial and energy transport of the injected EPs (neutral beam injection (NBI) or fusion alpha). The EPtran code is illustrated by treating the transport of NBI fast ions from high-n ITG/TEM micro-turbulence and EP driven unstable low-n Alfvén eigenmodes (AEs) in a well-studied DIII-D NBI heated discharge with significant AE central core loss. The kinetic transport code results for this discharge are compared with previous study using a simple EP density moment transport code ALPHA (R.E. Waltz and E.M. Bass 2014 Nucl. Fusion 54 104006). The dominant EP-AE transport is treated with a local stiff critical EP density (or equivalent pressure) gradient radial transport model modified to include energy-dependence and the nonlocal effects EP drift orbits. All previous EP transport models assume that the EP velocity space distribution function is not significantly distorted from the classical ‘no transport’ slowing down distribution. Important transport distortions away from the slowing down EP spectrum are illustrated by a focus on the coefficient of convection: EP energy flux divided by the product of EP average energy and EP particle flux.

  14. Fast Ion Confinement in High Beta, Steady-State Scenario Plasmas

    NASA Astrophysics Data System (ADS)

    Heidbrink, W. W.; Chen, X.; Ferron, J. R.; van Zeeland, M. A.; Grierson, B. A.; Holcomb, C. T.

    2013-10-01

    Fast-ion confinement is studied for qmin between 1.2-2.8 in plasmas with normalized β > 2 . 6 . Fast-ion D-alpha (FIDA), neutron, and neutral-particle diagnostics measure the confined fast ions. Tearing modes and a ``sea'' of unstable Alfvén eigenmodes (AE) are observed. In preliminary analysis, the degradation in fast-ion confinement increases with qmin ; increased AE activity appears responsible. Predictions of a model that assumes that AE-induced fast-ion transport is stiff are compared with the data. Work supported by the US Department of Energy under SC-G903402, DE-FC-02-04ER54698, DE-AC02-09CH11466, and DE-AC52-07NA27344.

  15. Overview of TFTR transport studies

    SciTech Connect

    Hawryluk, R.J.; Arunasalam, V.; Beer, M.; Bell, M.; Bell, R.; Biglari, H.; Bitter, M.; Boivin, R.; Bretz, N.L.; Budny, R.; Cheng, C.Z.; Chu, T.K.; Cohen, S.A.; Cowley, S.; Efthimion, P.C.; Fredrickson, E.; Furth, H.P.; Goldston, R.J.; Greene, G.; Grek, B.; Grisham, L.R.; Hammett, G.; Hill, K.W.; Hosea, J.; Hulse, R.A.; Hsuan, H.; Janos, A.; Jassby, D.; Jobes, F.C.; Johnson, D.W.; Johnson, L.C.; Kieras-Phillips, C.; Kilpatrick, S

    1991-10-01

    A review of TFTR plasma transport studies is presented. Parallel transport and the confinement of suprathermal ions are found to be relatively well described by theory. Cross-field transport of the thermal plasma, however, is anomalous with the momentum diffusivity being comparable to the ion thermal diffusivity and larger than the electron thermal diffusivity in neutral beam heated discharges. Perturbative experiments have studied non-linear dependencies in the transport coefficients and examined the role of possible non-local phenomena. The underlying turbulence has been studied using microwave scattering, beam emission spectroscopy and microwave reflectometry over a much broader range in k{perpendicular} than previously possible. Results indicate the existence of large-wavelength fluctuations correlated with enhanced transport. MHD instabilities set important operational constraints. However, by modifying the current profile using current ramp-down techniques, it has been possible to extend the operating regime to higher values of both {var epsilon}{beta}{sub p} and normalized {beta}{sub T}. In addition, the interaction of MHD fluctuations with fast ions, of potential relevance to {alpha}-particle confinement in D-T plasmas, has been investigated. The installation of carbon-carbon composite tiles and improvements in wall conditioning, in particular the use of Li pellet injection to reduce the carbon recycling, continue to be important in the improvement of plasma performance. 96 refs., 16 figs.

  16. Review of fast monte carlo codes for dose calculation in radiation therapy treatment planning.

    PubMed

    Jabbari, Keyvan

    2011-01-01

    An important requirement in radiation therapy is a fast and accurate treatment planning system. This system, using computed tomography (CT) data, direction, and characteristics of the beam, calculates the dose at all points of the patient's volume. The two main factors in treatment planning system are accuracy and speed. According to these factors, various generations of treatment planning systems are developed. This article is a review of the Fast Monte Carlo treatment planning algorithms, which are accurate and fast at the same time. The Monte Carlo techniques are based on the transport of each individual particle (e.g., photon or electron) in the tissue. The transport of the particle is done using the physics of the interaction of the particles with matter. Other techniques transport the particles as a group. For a typical dose calculation in radiation therapy the code has to transport several millions particles, which take a few hours, therefore, the Monte Carlo techniques are accurate, but slow for clinical use. In recent years, with the development of the 'fast' Monte Carlo systems, one is able to perform dose calculation in a reasonable time for clinical use. The acceptable time for dose calculation is in the range of one minute. There is currently a growing interest in the fast Monte Carlo treatment planning systems and there are many commercial treatment planning systems that perform dose calculation in radiation therapy based on the Monte Carlo technique.

  17. Rapid solute transport in the peritoneum: physiologic and clinical consequences.

    PubMed

    Cueto-Manzano, Alfonso M

    2009-02-01

    This review focuses on the physiologic and clinical consequences of rapid solute transport in the peritoneum. The concept, the current understanding of related factors, and the possible causes implicated in rapid solute transport are discussed first. Then, the consequences, with particular emphasis on mortality, are highlighted. Finally, based on recent advances and clinical studies, some strategies for the treatment of fast peritoneal transport are reviewed.

  18. Study of plasma heating induced by fast electrons

    NASA Astrophysics Data System (ADS)

    Morace, A.; Magunov, A.; Batani, D.; Redaelli, R.; Fourment, C.; Santos, J. J.; Malka, G.; Boscheron, A.; Casner, A.; Nazarov, W.; Vinci, T.; Okano, Y.; Inubushi, Y.; Nishimura, H.; Flacco, A.; Spindloe, C.; Tolley, M.

    2009-12-01

    We studied the induced plasma heating in three different kinds of targets: mass limited, foam targets, and large mass targets. The experiment was performed at Alisé Laser Facility of CEA/CESTA. The laser system emitted a ˜1 ps pulse with ˜10 J energy at a wavelength of ˜1 μm. Mass limited targets had three layers with thicknesses of 10 μm C8H8, 1 μm C8H7Cl, and 10 μm C8H8 with size of 100×100 μm2. Detailed spectroscopic analysis of x rays emitted from the Cl tracer showed that it was possible to heat up the plasma from mass limited targets to a temperature of ˜250 eV with density of ˜1021 cm-3. The plasma heating is only produced by fast electron transport in the target, being the 10 μm C8H8 overcoating thick enough to prevent any possible direct irradiation of the tracer layer even taking into account mass-ablation due to the prepulse. These results demonstrate that with mass limited targets, it is possible to generate a plasma heated up to several hundreds eV. It is also very important for research concerning high energy density phenomena and for fast ignition (in particular for the study of fast electrons transport and induced heating).

  19. Fast Ignitor Research at ILE Osaka University

    NASA Astrophysics Data System (ADS)

    Kodama, Ryosuke

    2000-10-01

    We have studied ultra-intense laser plasma interactions related to the Fast ignitor in inertial fusion energy. The interactions were investigated by using 50-100TW laser systems. Among the issues to be studied, we focused on the transport of high-density relativistic electrons and heating of high-density plasmas as well as the generation of the electrons in long scale-length plasmas. Laser propagation experiments were conducted changing the focal position of the 100 TW beam along the laser axis relative to the preformed plasma. X-ray hot spots appeared on the target surface, indicating that the ultra-intense laser light penetrated in this long scale preformed plasmas close to the solid target surface (super-penetration). At the super-penetration mode, high-density relativistic electrons and their transport were measured both inside and outside the target. Even with the long scale-length plasmas, the coupling efficiency of the laser energy to the electrons in the laser direction was 25from Ka x-ray (cf. the efficiency without the preformed plasma was 40high-density relativistic electros was investigated by 2-dimensional time-resolved UV images, XUV spectra from the target rear side and thermal neutrons from the target inside. The images show the filament and channel of the electron heating in the solid targets. The temperature of the plasma heated by the high-density relativistic electrons was evaluated to be a few 100 eV. These results indicate the channeling of the relativistic electrons in the solid plasmas. To investigate the heating of high-density plasmas, the 100TW laser light was focused into spherical implosion plasmas. The super-penetration mode was applied to this investigation as a self-guiding of the heating pulse. As an advanced fast ignitor target, we also proposed cone-guide targets to efficiently heat the core plasma without long scale-length plasmas and demonstrated the cone guide interactions for the first time.

  20. Direct Energy Conversion for Fast Reactors

    SciTech Connect

    Brown, N.; Cooper, J.; Vogt, D.; Chapline, G.; Turchi, P.; Barbee Jr., T.; Farmer, J.

    2000-07-01

    Strategic Computing Initiative (ASCI), should improve the speed and decrease the cost of developing new TEGs. The system concept to be evaluated is shown in Figure 1. Liquid metal is used to transport heat away from the nuclear heat source and to the TEG. Air or liquid (water or a liquid metal) is used to transport heat away from the cold side of the TEG. Typical reactor coolants include sodium or eutectic mixtures of lead-bismuth. These are coolants that have been used to cool fast neutron reactors. Heat from the liquid metal coolant is rejected through the thermal electric materials, thereby producing electrical power directly. The temperature gradient could extend from as high as 1300 K to 300 K, although fast reactor structural materials (including those used to clad the fuel) currently used limit the high temperature to about 825K.

  1. Fast ignition integrated experiments and high-gain point design

    SciTech Connect

    Shiraga, H.; Nagatomo, H.; Theobald, W.; Solodov, A. A.; Tabak, M.

    2014-04-17

    Here, integrated fast ignition experiments were performed at ILE, Osaka, and LLE, Rochester, in which a nanosecond driver laser implodes a deuterated plastic shell in front of the tip of a hollow metal cone and an intense ultrashort-pulse laser is injected through the cone to heat the compressed plasma. Based on the initial successful results of fast electron heating of cone-in-shell targets, large-energy short-pulse laser beam lines were constructed and became operational: OMEGA-EP at Rochester and LFEX at Osaka. Neutron enhancement due to heating with a ~kJ short-pulse laser has been demonstrated in the integrated experiments at Osaka and Rochester. The neutron yields are being analyzed by comparing the experimental results with simulations. Details of the fast electron beam transport and the electron energy deposition in the imploded fuel plasma are complicated and further studies are imperative. The hydrodynamics of the implosion was studied including the interaction of the imploded core plasma with the cone tip. Theory and simulation studies are presented on the hydrodynamics of a high-gain target for a fast ignition point design.

  2. Fast particle loss channels in Wendelstein 7-X

    NASA Astrophysics Data System (ADS)

    Faustin, J. M.; Cooper, W. A.; Graves, J. P.; Pfefferlé, D.; Geiger, J.

    2016-09-01

    One of the main goals of Wendelstein 7-X (W7-X) is to demonstrate the fast particle confinement properties of the quasi-isodynamic stellarator concept. Fast particle populations will be produced either by Neutral Beam Injection (NBI) or by minority Ion Cyclotron Resonant Heating (ICRH). A fraction of these particles are expected to be lost (even without collisions), despite the optimisation procedure used for the W7-X design. Confinement properties of NBI particles in W7-X were presented in the paper of Drevlak et al (2014 Nucl. Fusion 54 073002). A detailed study is presented here where the loss patterns of an NBI population are described. In particular, focussing on a high-mirror equilibrium, the confinement of fast ions with varying energy injection is studied under collisional conditions. It is found that collisions are not only responsible for classical transport losses but also enhance drift induced losses caused by trapped particles. Moreover, an asymmetry is found in the toroidal position of particle losses which can be explained by local variation in the equilibrium field. The effects of a neoclassically resolved radial electric field are also investigated. Fast particle confinement is significantly improved by the associated \\boldsymbol{E}× \\boldsymbol{B} drift. In particular, an increasing radial electric field helps to reduce and even stop the losses due to the 3D equilibrium structure for times comparable to slowing down time.

  3. New fast closing shutter for the PETRA III beamlines

    NASA Astrophysics Data System (ADS)

    Hahn, U.; Hesse, M.; Müller, S.; Peters, H.-B.; Timmann, B.; Wengler, R.; Zink, H.

    2008-03-01

    The conversion of the PETRA storage ring at the Deutsches Elektronen Synchrotron (DESY) to the third generation synchrotron radiation light source PETRAIII [1] poses a challenge to the design of the beamline transport system. One of these challenges is to supply 14 beamlines and experiments windowless with the extremely collimated undulator radiation from the storage ring. The windowless connection includes the risk of accidental venting of the storage ring by experiments connected to the beamlines. To stop the inrush of such an accidental venting fast closing shutter (FCS) systems with closing times in the 10msec range are mandatory. The strong radiation background in the storage ring tunnel requires the installation of all metal valves. A new small fast closing shutter with an aperture of 40mm fitting to the strong collimated undulator beams and with a closing time < 10msec was developed. The all metal sealing principle achieves leak rates smaller than 10mbarl/sec. This leak rate of the fast closing shutter combined with a standard all metal valve prevents venting of the storage ring and the beam time losses for all users. The mechanical and electronic layouts as well as first experiences with the new fast closing shutter system developed for PETRAIII are presented.

  4. A fast meteor detection algorithm

    NASA Astrophysics Data System (ADS)

    Gural, P.

    2016-01-01

    A low latency meteor detection algorithm for use with fast steering mirrors had been previously developed to track and telescopically follow meteors in real-time (Gural, 2007). It has been rewritten as a generic clustering and tracking software module for meteor detection that meets both the demanding throughput requirements of a Raspberry Pi while also maintaining a high probability of detection. The software interface is generalized to work with various forms of front-end video pre-processing approaches and provides a rich product set of parameterized line detection metrics. Discussion will include the Maximum Temporal Pixel (MTP) compression technique as a fast thresholding option for feeding the detection module, the detection algorithm trade for maximum processing throughput, details on the clustering and tracking methodology, processing products, performance metrics, and a general interface description.

  5. Causes of Extremely Fast CMEs

    NASA Technical Reports Server (NTRS)

    Feynman, Joan; Ruzmaikin, Alexander

    2006-01-01

    We study CMEs observed by LASCO to have plane of the sky velocities exceeding 1500 km/sec. We find that these extremely fast CMEs are typically associated with flares accompanied by erupting prominences. Our results are consistent with a single CME initiation process that consists of three stages. The initial stage is brought about by the emergence of new magnetic flux, which interacts with the pre-existing magnetic configuration and results in a slow rise of the magnetic structure. The second stage is a fast reconnection phase with flaring, filament eruption and a sudden increase of the rise velocity of the magnetic structure (CME). The third stage consists of propagation in the corona. We discuss the sources of these CMEs and the need for improved understanding of the first and third stages.

  6. Fast quench reactor and method

    DOEpatents

    Detering, Brent A.; Donaldson, Alan D.; Fincke, James R.; Kong, Peter C.

    2002-01-01

    A fast quench reaction includes a reactor chamber having a high temperature heating means such as a plasma torch at its inlet and a restrictive convergent-divergent nozzle at its outlet end. Reactants are injected into the reactor chamber. The resulting heated gaseous stream is then rapidly cooled by passage through the nozzle. This "freezes" the desired end product(s) in the heated equilibrium reaction stage.

  7. Fast quench reactor and method

    DOEpatents

    Detering, Brent A.; Donaldson, Alan D.; Fincke, James R.; Kong, Peter C.

    2002-09-24

    A fast quench reaction includes a reactor chamber having a high temperature heating means such as a plasma torch at its inlet and a restrictive convergent-divergent nozzle at its outlet end. Reactants are injected into the reactor chamber. The resulting heated gaseous stream is then rapidly cooled by passage through the nozzle. This "freezes" the desired end product(s) in the heated equilibrium reaction stage.

  8. Fast quench reactor and method

    DOEpatents

    Detering, Brent A.; Donaldson, Alan D.; Fincke, James R.; Kong, Peter C.

    1998-01-01

    A fast quench reaction includes a reactor chamber having a high temperature heating means such as a plasma torch at its inlet and a restrictive convergent-divergent nozzle at its outlet end. Reactants are injected into the reactor chamber. The resulting heated gaseous stream is then rapidly cooled by passage through the nozzle. This "freezes" the desired end product(s) in the heated equilibrium reaction stage.

  9. Fast track to 340B.

    PubMed

    Gricius, Robert F; Wong, Douglas

    2016-01-01

    Hospitals that are newly qualified for the 340B Drug Pricing Program may have an opportunity for fast-track approval to participate in the program. Three steps are required to seize this opportunity: Use data analytics to assess current and future percentages of Medicaid utilization and eligibility for federal SSI cash benefits. Determine the feasibility of early cost report filing. Prepare appropriate documentation and undertake the initial enrollment process. PMID:26863836

  10. Fast track to 340B.

    PubMed

    Gricius, Robert F; Wong, Douglas

    2016-01-01

    Hospitals that are newly qualified for the 340B Drug Pricing Program may have an opportunity for fast-track approval to participate in the program. Three steps are required to seize this opportunity: Use data analytics to assess current and future percentages of Medicaid utilization and eligibility for federal SSI cash benefits. Determine the feasibility of early cost report filing. Prepare appropriate documentation and undertake the initial enrollment process.

  11. Fast quench reactor and method

    DOEpatents

    Detering, B.A.; Donaldson, A.D.; Fincke, J.R.; Kong, P.C.

    1998-05-12

    A fast quench reactor includes a reactor chamber having a high temperature heating means such as a plasma torch at its inlet and a restrictive convergent-divergent nozzle at its outlet end. Reactants are injected into the reactor chamber. The resulting heated gaseous stream is then rapidly cooled by passage through the nozzle. This ``freezes`` the desired end product(s) in the heated equilibrium reaction stage. 7 figs.

  12. A repeating fast radio burst.

    PubMed

    Spitler, L G; Scholz, P; Hessels, J W T; Bogdanov, S; Brazier, A; Camilo, F; Chatterjee, S; Cordes, J M; Crawford, F; Deneva, J; Ferdman, R D; Freire, P C C; Kaspi, V M; Lazarus, P; Lynch, R; Madsen, E C; McLaughlin, M A; Patel, C; Ransom, S M; Seymour, A; Stairs, I H; Stappers, B W; van Leeuwen, J; Zhu, W W

    2016-03-10

    Fast radio bursts are millisecond-duration astronomical radio pulses of unknown physical origin that appear to come from extragalactic distances. Previous follow-up observations have failed to find additional bursts at the same dispersion measure (that is, the integrated column density of free electrons between source and telescope) and sky position as the original detections. The apparent non-repeating nature of these bursts has led to the suggestion that they originate in cataclysmic events. Here we report observations of ten additional bursts from the direction of the fast radio burst FRB 121102. These bursts have dispersion measures and sky positions consistent with the original burst. This unambiguously identifies FRB 121102 as repeating and demonstrates that its source survives the energetic events that cause the bursts. Additionally, the bursts from FRB 121102 show a wide range of spectral shapes that appear to be predominantly intrinsic to the source and which vary on timescales of minutes or less. Although there may be multiple physical origins for the population of fast radio bursts, these repeat bursts with high dispersion measure and variable spectra specifically seen from the direction of FRB 121102 support an origin in a young, highly magnetized, extragalactic neutron star. PMID:26934226

  13. Fast superconducting magnetic field switch

    DOEpatents

    Goren, Yehuda; Mahale, Narayan K.

    1996-01-01

    The superconducting magnetic switch or fast kicker magnet is employed with electron stream or a bunch of electrons to rapidly change the direction of flow of the electron stream or bunch of electrons. The apparatus employs a beam tube which is coated with a film of superconducting material. The tube is cooled to a temperature below the superconducting transition temperature and is subjected to a constant magnetic field which is produced by an external dc magnet. The magnetic field produced by the dc magnet is less than the critical field for the superconducting material, thus, creating a Meissner Effect condition. A controllable fast electromagnet is used to provide a magnetic field which supplements that of the dc magnet so that when the fast magnet is energized the combined magnetic field is now greater that the critical field and the superconducting material returns to its normal state allowing the magnetic field to penetrate the tube. This produces an internal field which effects the direction of motion and of the electron stream or electron bunch. The switch can also operate as a switching mechanism for charged particles.

  14. Heterogeneous Transmutation Sodium Fast Reactor

    SciTech Connect

    S. E. Bays

    2007-09-01

    The threshold-fission (fertile) nature of Am-241 is used to destroy this minor actinide by capitalizing upon neutron capture instead of fission within a sodium fast reactor. This neutron-capture and its subsequent decay chain leads to the breeding of even neutron number plutonium isotopes. A slightly moderated target design is proposed for breeding plutonium in an axial blanket located above the active “fast reactor” driver fuel region. A parametric study on the core height and fuel pin diameter-to-pitch ratio is used to explore the reactor and fuel cycle aspects of this design. This study resulted in both non-flattened and flattened core geometries. Both of these designs demonstrated a high capacity for removing americium from the fuel cycle. A reactivity coefficient analysis revealed that this heterogeneous design will have comparable safety aspects to a homogeneous reactor of comparable size. A mass balance analysis revealed that the heterogeneous design may reduce the number of fast reactors needed to close the current once-through light water reactor fuel cycle.

  15. A repeating fast radio burst.

    PubMed

    Spitler, L G; Scholz, P; Hessels, J W T; Bogdanov, S; Brazier, A; Camilo, F; Chatterjee, S; Cordes, J M; Crawford, F; Deneva, J; Ferdman, R D; Freire, P C C; Kaspi, V M; Lazarus, P; Lynch, R; Madsen, E C; McLaughlin, M A; Patel, C; Ransom, S M; Seymour, A; Stairs, I H; Stappers, B W; van Leeuwen, J; Zhu, W W

    2016-03-10

    Fast radio bursts are millisecond-duration astronomical radio pulses of unknown physical origin that appear to come from extragalactic distances. Previous follow-up observations have failed to find additional bursts at the same dispersion measure (that is, the integrated column density of free electrons between source and telescope) and sky position as the original detections. The apparent non-repeating nature of these bursts has led to the suggestion that they originate in cataclysmic events. Here we report observations of ten additional bursts from the direction of the fast radio burst FRB 121102. These bursts have dispersion measures and sky positions consistent with the original burst. This unambiguously identifies FRB 121102 as repeating and demonstrates that its source survives the energetic events that cause the bursts. Additionally, the bursts from FRB 121102 show a wide range of spectral shapes that appear to be predominantly intrinsic to the source and which vary on timescales of minutes or less. Although there may be multiple physical origins for the population of fast radio bursts, these repeat bursts with high dispersion measure and variable spectra specifically seen from the direction of FRB 121102 support an origin in a young, highly magnetized, extragalactic neutron star.

  16. Fast superconducting magnetic field switch

    DOEpatents

    Goren, Y.; Mahale, N.K.

    1996-08-06

    The superconducting magnetic switch or fast kicker magnet is employed with electron stream or a bunch of electrons to rapidly change the direction of flow of the electron stream or bunch of electrons. The apparatus employs a beam tube which is coated with a film of superconducting material. The tube is cooled to a temperature below the superconducting transition temperature and is subjected to a constant magnetic field which is produced by an external dc magnet. The magnetic field produced by the dc magnet is less than the critical field for the superconducting material, thus, creating a Meissner Effect condition. A controllable fast electromagnet is used to provide a magnetic field which supplements that of the dc magnet so that when the fast magnet is energized the combined magnetic field is now greater that the critical field and the superconducting material returns to its normal state allowing the magnetic field to penetrate the tube. This produces an internal field which effects the direction of motion and of the electron stream or electron bunch. The switch can also operate as a switching mechanism for charged particles. 6 figs.

  17. Mobile Transporter

    NASA Technical Reports Server (NTRS)

    2001-01-01

    The Space Shuttle Atlantis, STS-110 mission, deployed this railcar, called the Mobile Transporter, and an initial 43-foot section of track, the S0 (S-zero) truss, preparing the International Space Station (ISS) for future spacewalks. The first railroad in space, the Mobile Transporter will allow the Station's robotic arm to travel up and down the finished truss for future assembly and maintenance. The 27,000-pound S0 truss is the first of 9 segments that will make up the Station's external framework that will eventually stretch 356 feet (109 meters), or approximately the length of a football field. The completed truss structure will hold solar arrays and radiators to provide power and cooling for additional international research laboratories from Japan and Europe that will be attached to the Station. The Space Shuttle Orbiter Atlantis, STS-110 mission, was launched April 8, 2002 and returned to Earth April 19, 2002. STS-110's Extravehicular Activity (EVA) marked the first use of the Station's robotic arm to maneuver spacewalkers around the Station.

  18. General adaptive guidance using nonlinear programming constraint solving methods (FAST)

    NASA Astrophysics Data System (ADS)

    Skalecki, Lisa; Martin, Marc

    An adaptive, general purpose, constraint solving guidance algorithm called FAST (Flight Algorithm to Solve Trajectories) has been developed by the authors in response to the requirements for the Advanced Launch System (ALS). The FAST algorithm can be used for all mission phases for a wide range of Space Transportation Vehicles without code modification because of the general formulation of the nonlinear programming (NLP) problem, ad the general trajectory simulation used to predict constraint values. The approach allows on board re-targeting for severe weather and changes in payload or mission parameters, increasing flight reliability and dependability while reducing the amount of pre-flight analysis that must be performed. The algorithm is described in general in this paper. Three degree of freedom simulation results are presented for application of the algorithm to ascent and reentry phases of an ALS mission, and Mars aerobraking. Flight processor CPU requirement data is also shown.

  19. FAST20XX: Achievements On European Suborbital Space Flight

    NASA Astrophysics Data System (ADS)

    Mack, A.; Steelant, J.; Adirim, H.; Lentsch, A.; Marini, M.; Pilz, N.

    2011-05-01

    In Europe, the EC co-funded project FAST20XX aims at exploring the borderline between aviation and space by investigating suborbital vehicles. The main focus is the identification and mastering of critical technologies for such vehicles rather than the vehicle development itself. Besides the objectives and overall layout of the project, the paper addresses also the progress made during the first period of the project. Two vehicle concepts are considered. A first one is a space vehicle launched from an airplane providing a low-energy ballistic flight experience using hybrid propulsion. The second is a vertically starting two-stage rocket space vehicle system concept taken as a basis to identify the conditions and constraints experienced during high- energy suborbital ultra-fast transport. The paper mainly discusses the two actual reference vehicles and the technical aspects of prerequisites for commercial operation including safety, human spaceflight, business cases, environmental and legal issues.

  20. Proton Transport

    NASA Technical Reports Server (NTRS)

    Pohorille, Andrew; DeVincenzi, Donald L. (Technical Monitor)

    2001-01-01

    The transport of protons across membranes is an essential process for both bioenergetics of modern cells and the origins of cellular life. All living systems make use of proton gradients across cell walls to convert environmental energy into a high-energy chemical compound, adenosine triphosphate (ATP), synthesized from adenosine diphosphate. ATP, in turn, is used as a source of energy to drive many cellular reactions. The ubiquity of this process in biology suggests that even the earliest cellular systems were relying on proton gradient for harvesting environmental energy needed to support their survival and growth. In contemporary cells, proton transfer is assisted by large, complex proteins embedded in membranes. The issue addressed in this Study was: how the same process can be accomplished with the aid of similar but much simpler molecules that could have existed in the protobiological milieu? The model system used in the study contained a bilayer membrane made of phospholipid, dimyristoylphosphatidylcholine (DMPC) which is a good model of the biological membranes forming cellular boundaries. Both sides of the bilayer were surrounded by water which simulated the environment inside and outside the cell. Embedded in the membrane was a fragment of the Influenza-A M$_2$ protein and enough sodium counterions to maintain system neutrality. This protein has been shown to exhibit remarkably high rates of proton transport and, therefore, is an excellent model to study the formation of proton gradients across membranes. The Influenza M$_2$ protein is 97 amino acids in length, but a fragment 25 amino acids long. which contains a transmembrane domain of 19 amino acids flanked by three amino acids on each side. is sufficient to transport protons. Four identical protein fragments, each folded into a helix, aggregate to form small channels spanning the membrane. Protons are conducted through a narrow pore in the middle of the channel in response to applied voltage. This

  1. The digital backend of FAST

    NASA Astrophysics Data System (ADS)

    Yu, Xinying; Zhang, Xia; Duan, Ran; li, di; Hao, Jie

    2015-08-01

    The receiver system is an important part of FAST (Five-hundred-meter Aperture Spherical Radio Telescope) and plays a key role in determining the performance of the telescope.This research covers three major aspects: establishment of system synchronization and timestamps, field-programmable gate array (FPGA)-based data transmission and analysis, and the rear receiver monitoring system. We intend to combine the use of GPS and a frequency standard instrument with network access to Unix timestamps to form actual timestamps. The data are stored with timestamps that contain integer and fractional seconds to be precise and headers, which are primarily intended to distinguish the data from each other.The data analysis procedures includes converting the timestamp information to real-time information, and merging the 8 channels’ data conversion results into frequency and energy data using corresponding conversion formulae. We must develop tailored monitoring software for the FAST receiver to customize the data format and perform data transmission. Signals on the front-end and back-end of the receiver can be monitored and controlled by adjusting the parameters on the software to increase the flexibility of the receiver.Most operations are performed on FPGA board, which can be shown from the figure, including the analog-to-digital conversion (ADC), fast Fourier transform (FFT), and pulse per second (1PPS) and Unix timestamp access operations.When analog data arrive, we initialize two ADCs at a sampling rate of 3Gsps, following by 8-channel FFT parallel processing.In collaboration with the Institute of Automation, we have developed a custom FPGA board which we call "FDB"("FAST Digital Backend"). The board is integrated with two Virtex-6 and one Virtex-5 high-speed Xilinx chips. The main function of the two Virtex-6 devices is to run the FFT and PFB programs, whereas the main function of Virtex-5 is configuration of the board.This research is indispensable for realizing the

  2. Fasting Increases Tobramycin Oral Absorption in Mice▿

    PubMed Central

    De Leo, Luigina; Di Toro, Nicola; Decorti, Giuliana; Malusà, Noelia; Ventura, Alessandro; Not, Tarcisio

    2010-01-01

    The pharmacokinetics of the aminoglycoside tobramycin was evaluated after oral administration to fed or fasting (15 h) mice. As expected, under normal feeding conditions, oral absorption was negligible; however, fasting induced a dramatic increase in tobramycin bioavailability. The dual-sugar test with lactulose and l-rhamnose confirmed increased small bowel permeability via the paracellular route in fasting animals. When experiments aimed at increasing the oral bioavailability of hydrophilic compounds are performed, timing of fasting should be extremely accurate. PMID:20086144

  3. A TURBULENCE-DRIVEN MODEL FOR HEATING AND ACCELERATION OF THE FAST WIND IN CORONAL HOLES

    SciTech Connect

    Verdini, A.; Velli, M.; Matthaeus, W. H.; Oughton, S.; Dmitruk, P.

    2010-01-10

    A model is presented for generation of fast solar wind in coronal holes, relying on heating that is dominated by turbulent dissipation of MHD fluctuations transported upward in the solar atmosphere. Scale-separated transport equations include large-scale fields, transverse Alfvenic fluctuations, and a small compressive dissipation due to parallel shears near the transition region. The model accounts for proton temperature, density, wind speed, and fluctuation amplitude as observed in remote sensing and in situ satellite data.

  4. Comparison of model results transporting the odd nitrogen family with results transporting separate odd nitrogen species

    NASA Technical Reports Server (NTRS)

    Douglass, Anne R.; Jackman, Charles H.; Stolarski, Richard S.

    1989-01-01

    A fast two-dimensional residual circulation stratospheric family transport model, designed to minimize computer requirements, is developed. The model was used to calculate the ambient and perturbed atmospheres in which odd nitrogen species are transported as a family, and the results were compared with calculations in which HNO3, N2O5, ClONO2, and HO2NO2 are transported separately. It was found that ozone distributions computed by the two models for a present-day atmosphere are nearly identical. Good agreement was also found between calculated species concentrations and the ozone response, indicating the general applicability of the odd-nitrogen family approximations.

  5. Fast neutron imaging device and method

    DOEpatents

    Popov, Vladimir; Degtiarenko, Pavel; Musatov, Igor V.

    2014-02-11

    A fast neutron imaging apparatus and method of constructing fast neutron radiography images, the apparatus including a neutron source and a detector that provides event-by-event acquisition of position and energy deposition, and optionally timing and pulse shape for each individual neutron event detected by the detector. The method for constructing fast neutron radiography images utilizes the apparatus of the invention.

  6. Fast Foods, Organic Foods, Fad Diets

    Technology Transfer Automated Retrieval System (TEKTRAN)

    There is no standard definition of fast food. Generally, fast food is eaten without cutlery, and fast-food restaurants have no wait staff. Failure to have a standardized definition makes it difficult to compare studies. Foods available outside the home tend to be high in energy and fat compared w...

  7. LFR "Lead-Cooled Fast Reactor"

    SciTech Connect

    Cinotti, L; Fazio, C; Knebel, J; Monti, S; Abderrahim, H A; Smith, C; Suh, K

    2006-05-11

    The main purpose of this paper is to present the current status of development of the Lead-cooled Fast Reactor (LFR) in Generation IV (GEN IV), including the European contribution, to identify needed R&D and to present the corresponding GEN IV International Forum (GIF) R&D plan [1] to support the future development and deployment of lead-cooled fast reactors. The approach of the GIF plan is to consider the research priorities of each member country in proposing an integrated, coordinated R&D program to achieve common objectives, while avoiding duplication of effort. The integrated plan recognizes two principal technology tracks: (1) a small, transportable system of 10-100 MWe size that features a very long refuelling interval, and (2) a larger-sized system rated at about 600 MWe, intended for central station power generation. This paper provides some details of the important European contributions to the development of the LFR. Sixteen European organizations have, in fact, taken the initiative to present to the European Commission the proposal for a Specific Targeted Research and Training Project (STREP) devoted to the development of a European Lead-cooled System, known as the ELSY project; two additional organizations from the US and Korea have joined the project. Consequently, ELSY will constitute the reference system for the large lead-cooled reactor of GEN IV. The ELSY project aims to demonstrate the feasibility of designing a competitive and safe fast power reactor based on simple technical engineered features that achieves all of the GEN IV goals and gives assurance of investment protection. As far as new technology development is concerned, only a limited amount of R&D will be conducted in the initial phase of the ELSY project since the first priority is to define the design guidelines before launching a larger and expensive specific R&D program. In addition, the ELSY project is expected to benefit greatly from ongoing lead and lead-alloy technology

  8. Regimes of suprathermal electron transport

    SciTech Connect

    Glinsky, M.E.

    1995-07-01

    Regimes of the one-dimensional (1-D) transport of suprathermal electrons into a cold background plasma are delineated. A well ordered temporal progression is found through eras where {ital J}{center_dot}{ital E} heating, hot electron--cold electron collisional heating, and diffusive heat flow dominate the cold electron energy equation. Scaling relations for how important quantities such as the width and temperature of the heated layer of cold electrons evolve with time are presented. These scaling relations are extracted from a simple 1-D model of the transport which can be written in dimensionless form with one free parameter. The parameter is shown to be the suprathermal electron velocity divided by the drift velocity of cold electrons which balances the suprathermal current. Special attention is paid to the assumptions which allow the reduction from the collisional Vlasov equation, using a Fokker--Planck collision operator, to this simple model. These model equations are numerically solved and compared to both the scaling relations and a more complete multigroup electron diffusion transport. Implications of the scaling relations on fast ion generation, magnetic field generation, and electric field inhibition of electron transport are examined as they apply to laser heated plasmas. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.

  9. Generation of sheet currents by high frequency fast MHD waves

    NASA Astrophysics Data System (ADS)

    Núñez, Manuel

    2016-07-01

    The evolution of fast magnetosonic waves of high frequency propagating into an axisymmetric equilibrium plasma is studied. By using the methods of weakly nonlinear geometrical optics, it is shown that the perturbation travels in the equatorial plane while satisfying a transport equation which enables us to predict the time and location of formation of shock waves. For plasmas of large magnetic Prandtl number, this would result into the creation of sheet currents which may give rise to magnetic reconnection and destruction of the original equilibrium.

  10. Overview of recent progress in US fast ignition research

    SciTech Connect

    Freeman, R R; Akli, K; Beg, F; Betti, R; Chen, S; Clark, D J; Gu, P; Gregori, G; Hatchett, S P; Hey, D; Highbarger, K; Hill, J M; Izumi, N; Key, M H; King, J A; Koch, J A; Lasinski, B; Langdon, B; Mackinnon, A J; Meyerhofer, D; Patel, N; Patel, P; Pasley, J; Park, H; Ren, C; Snavely, R A; Stephens, R B; Stoeckl, C; Tabak, M; Town, R; Van Woerkom, L; Weber, R; Wilks, S C; Zhang, B

    2005-09-28

    The Fast Ignition Program in the United States has enjoyed increased funding in various forms from the Office of Fusion Energy Sciences of the Department of Energy. The program encompasses experiments on large laser facilities at various world-wide locations, and benefits enormously from collaborations with many international scientists. The program includes exploratory work in cone-target design and implosion dynamics, high electron current transport measurements in normal density materials, development of diagnostics for heating measurements, generation of protons from shaped targets, theoretical work on high gain target designs, and extensive modeling development using PIC and hybrid codes.

  11. Very fast thermal measurements by means of fast line scanning

    NASA Astrophysics Data System (ADS)

    Wallin, Bo

    1999-03-01

    Many thermal processes pass very quickly. The normal frame rate of radiometric scanners or FPA cameras is sometimes far below what might be needed in order to see what is happening with the object. When it comes to measurement there is nothing yet to match the measurement accuracy of the best scanning devices. When very high measurement accuracy has to be combined with highest possible data acquisition rate, the best way today is to use the scanning technique, with the scanner set for line scanning. Thus it is possible to acquire thermal information also from very fast processes. Computer processing of thermal information is today applied in almost 100% of the cases. If this is applied to thermal information, which is acquired by Fast line scanning, the results can be very interesting. This method has been successfully applied e.g. to tires, disk brakes, fusion research, and to analysis of explosions in connections with the development of air-bags. The paper describes the above mentioned applications. This includes a method description and some thermograms, which show the final result.

  12. Comparison of Fast-Food and Non-Fast-Food Children's Menu Items

    ERIC Educational Resources Information Center

    Serrano, Elena L.; Jedda, Virginia B.

    2009-01-01

    Objective: Compare the macronutrient content of children's meals sold by fast-food restaurants (FFR) and non-fast-food restaurants (NFF). Design: All restaurants within the designated city limits were surveyed. Non-fast-food children's meals were purchased, weighed, and analyzed using nutrition software. All fast-food children's meals were…

  13. Fast pulse nonthermal plasma reactor

    DOEpatents

    Rosocha, Louis A.

    2005-06-14

    A fast pulsed nonthermal plasma reactor includes a discharge cell and a charging assembly electrically connected thereto. The charging assembly provides plural high voltage pulses to the discharge cell. Each pulse has a rise time between one and ten nanoseconds and a duration of three to twenty nanoseconds. The pulses create nonthermal plasma discharge within the discharge cell. Accordingly, the nonthermal plasma discharge can be used to remove pollutants from gases or break the gases into smaller molecules so that they can be more efficiently combusted.

  14. Fast-acting valve actuator

    DOEpatents

    Cho, Nakwon

    1980-01-01

    A fast-acting valve actuator utilizes a spring driven pneumatically loaded piston to drive a valve gate. Rapid exhaust of pressurized gas from the pneumatically loaded side of the piston facilitates an extremely rapid piston stroke. A flexible selector diaphragm opens and closes an exhaust port in response to pressure differentials created by energizing and de-energizing a solenoid which controls the pneumatic input to the actuator as well as selectively providing a venting action to one side of the selector diaphragm.

  15. Fast feedback for linear colliders

    SciTech Connect

    Hendrickson, L.; Adolphsen, C.; Allison, S.; Gromme, T.; Grossberg, P.; Himel, T.; Krauter, K.; MacKenzie, R.; Minty, M.; Sass, R.

    1995-05-01

    A fast feedback system provides beam stabilization for the SLC. As the SLC is in some sense a prototype for future linear colliders, this system may be a prototype for future feedbacks. The SLC provides a good base of experience for feedback requirements and capabilities as well as a testing ground for performance characteristics. The feedback system controls a wide variety of machine parameters throughout the SLC and associated experiments, including regulation of beam position, angle, energy, intensity and timing parameters. The design and applications of the system are described, in addition to results of recent performance studies.

  16. Isochoric implosions for fast ignition

    SciTech Connect

    Clark, D S; Tabak, M

    2006-06-05

    Fast Ignition (FI) exploits the ignition of a dense, uniform fuel assembly by an external energy source to achieve high gain. In conventional ICF implosions, however, the fuel assembles as a dense shell surrounding a low density, high-pressure hotspot. Such configurations are far from optimal for FI. Here, it is shown that a self-similar spherical implosion of the type originally studied by Guderley [Luftfahrtforschung 19, 302 (1942).] may be employed to implode a dense, quasi-uniform fuel assembly with minimal energy wastage in forming a hotspot. A scheme for realizing these specialized implosions in a practical ICF target is also described.

  17. Lagrangian coherent structures and plasma transport processes

    NASA Astrophysics Data System (ADS)

    Falessi, M. V.; Pegoraro, F.; Schep, T. J.

    2015-10-01

    > A dynamical system framework is used to describe transport processes in plasmas embedded in a magnetic field. For periodic systems with one degree of freedom, the Poincaré map provides a splitting of the phase space into regions where particles have different kinds of motion: periodic, quasi-periodic or chaotic. The boundaries of these regions are transport barriers, i.e. a trajectory cannot cross such boundaries throughout the evolution of the system. Lagrangian coherent structures generalize this method to systems with the most general time dependence, splitting the phase space into regions with different qualitative behaviours. This leads to the definition of finite-time transport barriers, i.e. trajectories cannot cross the barrier for a finite amount of time. This methodology can be used to identify fast recirculating regions in the dynamical system and to characterize the transport between them.

  18. Linear and Nonlinear Study of Fast Particle Excitation of Alfvén Eigemodes

    SciTech Connect

    Berk, H.L.; Chen, Y.; Cheng, C.Z.; Fu, G.Y.; Gorelenkov, N.N; Gorelenkova, M.V.; Nazikian, R.; White, R.B.

    1998-11-01

    Recent new results concerning toroidicity-induced Alfvén eigenmode (TAE) linear stability and nonlinear amplitude saturation and associated fast ion transport are presented for tokamaks, such as the National Spherical Torus Experiment (NSTX) and the International Thermonuclear Experimental Reactor (ITER), using the numerical codes HINST, NOVA-K, and ORBIT.

  19. Glycolate transporter of the pea chloroplast envelope

    SciTech Connect

    Howitz, K.T.

    1985-01-01

    The discovery of a glycolate transporter in the pea (Pisum sativum) chloroplast envelope is described. Several novel silicone oil centrifugation methods were developed to resolve the initial rate kinetics of (/sup 14/C)glycolate transport by isolated, intact pea chloroplasts. Chloroplast glycolate transport was found to be carrier mediated. Transport rates saturated with increasing glycolate concentration. N-Ethylmaleimide (NEM) pretreatment of chloroplasts inhibited transport, an inhibition prevented by glycolate. Glycolate distributed across the envelope in a way which equalized stromal and medium glycolic acid concentrations, limiting possible transport mechanisms to facilitated glycolic acid diffusion, proton symport or hydroxyl antiport. The effects of stomal and medium pH's on the K/sub m/ and V/sub max/ fit the predictions of mobile carrier kinetic models of hydroxyl antiport or proton symport (H/sup +/ binds first). The carrier mediated transport was fast enough to be consistent with in vivo rates of photorespiration. The 2-hydroxymonocarboxylates, glycerate, lactate and glyoxylate are competitive inhibitors of chloroplast glycolate uptake. Glyoxylate, D-lactate and D-glycerate cause glycolate counterflow, indicating that they are also substrates of the glycolate carrier. This finding was confirmed for D-glycerate by studies on glycolate effects on (1-/sup 14/C)D-glycerate transport.

  20. Experimental investigation of fast electron diffusion during ECRH

    SciTech Connect

    Steimle, R.F.; Roberts, D.R.; Giruzzi, G.

    1995-06-07

    The spatial diffusion of fast electrons created by electron cyclotron resonant heating (ECRH) is examined using electron cyclotron emissions viewed along a nearly vertical chord in the TEXT-U tokamak. Enhanced emission at frequencies downshifted from the cold cyclotron frequency is attributed to non-thermal electrons. The emission spectra during ECRH are consistent with the presence of low density suprathermal electrons. Comparison of the spectra measured during ECRH with a bounce averaged Fokker-Planck code which incorporates the effects of magnetic and/or electrostatic turbulence on the distribution function, shows that the level of magnetic fluctuations in the center of TEXT-U is between 3 and 5 {times} 10{sup {minus}5}. This level of magnetic fluctuation is a factor of 2 to 5 too small to explain the transport of thermal electrons (E {approximately} 1 keV) in TEXT. Thus, magnetic fluctuations are an unlikely major cause of the transport of thermal electrons in TEXT.

  1. Influence of fast alpha diffusion and thermal alpha buildup on tokamak reactor performance

    SciTech Connect

    Uckan, N.A.; Tolliver, J.S.; Houlberg, W.A.; Attenberger, S.E.

    1987-11-01

    The effect of fast alpha diffusion and thermal alpha accumulation on the confinement capability of a candidate Engineering Test Reactor (ETR) plasma (Tokamak Ignition/Burn Experimental Reactor (TIBER-II)) in achieving ignition and steady-state driven operation has been assessed using both global and 1-1/2-D transport models. Estimates are made of the threshold for radial diffusion of fast alphas and thermal alpha buildup. It is shown that a relatively low level of radial transport, when combined with large gradients in the fast alpha density, leads to a significant radial flow with a deleterious effect on plasma performance. Similarly, modest levels of thermal alpha concentration significantly influence the ignition and steady-state burn capability. 23 refs., 9 figs., 4 tabs.

  2. Robotic transportation.

    PubMed

    Lob, W S

    1990-09-01

    Mobile robots perform fetch-and-carry tasks autonomously. An intelligent, sensor-equipped mobile robot does not require dedicated pathways or extensive facility modification. In the hospital, mobile robots can be used to carry specimens, pharmaceuticals, meals, etc. between supply centers, patient areas, and laboratories. The HelpMate (Transitions Research Corp.) mobile robot was developed specifically for hospital environments. To reach a desired destination, Help-Mate navigates with an on-board computer that continuously polls a suite of sensors, matches the sensor data against a pre-programmed map of the environment, and issues drive commands and path corrections. A sender operates the robot with a user-friendly menu that prompts for payload insertion and desired destination(s). Upon arrival at its selected destination, the robot prompts the recipient for a security code or physical key and awaits acknowledgement of payload removal. In the future, the integration of HelpMate with robot manipulators, test equipment, and central institutional information systems will open new applications in more localized areas and should help overcome difficulties in filling transport staff positions.

  3. Robotic transportation.

    PubMed

    Lob, W S

    1990-09-01

    Mobile robots perform fetch-and-carry tasks autonomously. An intelligent, sensor-equipped mobile robot does not require dedicated pathways or extensive facility modification. In the hospital, mobile robots can be used to carry specimens, pharmaceuticals, meals, etc. between supply centers, patient areas, and laboratories. The HelpMate (Transitions Research Corp.) mobile robot was developed specifically for hospital environments. To reach a desired destination, Help-Mate navigates with an on-board computer that continuously polls a suite of sensors, matches the sensor data against a pre-programmed map of the environment, and issues drive commands and path corrections. A sender operates the robot with a user-friendly menu that prompts for payload insertion and desired destination(s). Upon arrival at its selected destination, the robot prompts the recipient for a security code or physical key and awaits acknowledgement of payload removal. In the future, the integration of HelpMate with robot manipulators, test equipment, and central institutional information systems will open new applications in more localized areas and should help overcome difficulties in filling transport staff positions. PMID:2208684

  4. Nonequilibrium Interlayer Transport in Pulsed Laser Deposition

    SciTech Connect

    Tischler, Jonathan Zachary; Eres, Gyula; Larson, Ben C; Rouleau, Christopher M; Zschack, P.; Lowndes, Douglas H

    2006-01-01

    We use time-resolved surface x-ray diffraction measurements with microsecond range resolution to study the growth kinetics of pulsed laser deposited SrTiO3. Time-dependent surface coverages corresponding to single laser shots were determined directly from crystal truncation rod intensity transients. Analysis of surface coverage evolution shows that extremely fast nonequilibrium interlayer transport, which occurs concurrently with the arrival of the laser plume, dominates the deposition process. A much smaller fraction of material, which is governed by the dwell time between successive laser shots, is transferred by slow, thermally driven interlayer transport processes.

  5. Cortical Specializations Underlying Fast Computations

    PubMed Central

    Volgushev, Maxim

    2016-01-01

    The time course of behaviorally relevant environmental events sets temporal constraints on neuronal processing. How does the mammalian brain make use of the increasingly complex networks of the neocortex, while making decisions and executing behavioral reactions within a reasonable time? The key parameter determining the speed of computations in neuronal networks is a time interval that neuronal ensembles need to process changes at their input and communicate results of this processing to downstream neurons. Theoretical analysis identified basic requirements for fast processing: use of neuronal populations for encoding, background activity, and fast onset dynamics of action potentials in neurons. Experimental evidence shows that populations of neocortical neurons fulfil these requirements. Indeed, they can change firing rate in response to input perturbations very quickly, within 1 to 3 ms, and encode high-frequency components of the input by phase-locking their spiking to frequencies up to 300 to 1000 Hz. This implies that time unit of computations by cortical ensembles is only few, 1 to 3 ms, which is considerably faster than the membrane time constant of individual neurons. The ability of cortical neuronal ensembles to communicate on a millisecond time scale allows for complex, multiple-step processing and precise coordination of neuronal activity in parallel processing streams, while keeping the speed of behavioral reactions within environmentally set temporal constraints. PMID:25689988

  6. Manybeam velocimeter for fast surfaces

    SciTech Connect

    Goosman, D.; Avara, G.; Steinmetz, L.; Lai, C.; Perry, S.

    1996-09-01

    For the past 5 years, we have conceived, built and successfully used a new 10 beam laser velocimeter for monitoring velocity vs time histories of fast moving surfaces, and will have a 20 beam capability soon. We conceived a method to multiplex 5 to 10 beams through a single Fabry-Perot interferometer, without losing any light that our equivalently-performing single beam system could use, and with negligible cross- talk. This saves the cost of 16 interferometers, simplifies operation and takes less space than without multiplexing. We devised special efficient light collecting probes, streak cameras that change sweep speed during the course of the record, and a new double cavity interferometer which is better, cheaper and more flexible than our previous versions. With the 10 recorders, we conceived and employ a method of using both a fast and a slow streak camera on each of 5 beams without reducing the light that is available to either camera separately. Five new galvanometrically-driven triggerable CCD streak cameras will be installed soon.

  7. RCD+: Fast loop modeling server.

    PubMed

    López-Blanco, José Ramón; Canosa-Valls, Alejandro Jesús; Li, Yaohang; Chacón, Pablo

    2016-07-01

    Modeling loops is a critical and challenging step in protein modeling and prediction. We have developed a quick online service (http://rcd.chaconlab.org) for ab initio loop modeling combining a coarse-grained conformational search with a full-atom refinement. Our original Random Coordinate Descent (RCD) loop closure algorithm has been greatly improved to enrich the sampling distribution towards near-native conformations. These improvements include a new workflow optimization, MPI-parallelization and fast backbone angle sampling based on neighbor-dependent Ramachandran probability distributions. The server starts by efficiently searching the vast conformational space from only the loop sequence information and the environment atomic coordinates. The generated closed loop models are subsequently ranked using a fast distance-orientation dependent energy filter. Top ranked loops are refined with the Rosetta energy function to obtain accurate all-atom predictions that can be interactively inspected in an user-friendly web interface. Using standard benchmarks, the average root mean squared deviation (RMSD) is 0.8 and 1.4 Å for 8 and 12 residues loops, respectively, in the challenging modeling scenario in where the side chains of the loop environment are fully remodeled. These results are not only very competitive compared to those obtained with public state of the art methods, but also they are obtained ∼10-fold faster. PMID:27151199

  8. The Ignitor Fast Pellet Injector

    NASA Astrophysics Data System (ADS)

    Frattolillo, A.; Migliori, S.; Bombarda, F.; Milora, S. L.; Baylor, L. R.; Combs, S. K.

    2004-11-01

    A collaboration between the ENEA Laboratory at Frascati and the Fusion Technology Group of Oak Ridge for the development of a fast pellet injector for the Ignitor ignition experiment has been established. The program aims at the construction of a 4 barrel, double stage gun able to reach speeds up to 4 km/s and thus penetrate to the core of the plasma column. The compact size of the Ignitor machine favors the injection from the low field side, for which very positive results have been obtained on the FTU machine [1], in terms of density profile peaking and good energy confinement. The ongoing activities include the procurement of all the hardware for the criocooler, diagnostics and control electronics, from the ORNL side, and the design and construction of the gun by ENEA. A new fast valve has been developed that considerably reduces the requirements on the expansion volumes necessary to prevent the propulsion gas to reach the plasma chamber. [1] D. Frigione, et al., Nuclear Fusion 41, 1613 (2001).

  9. RCD+: Fast loop modeling server

    PubMed Central

    López-Blanco, José Ramón; Canosa-Valls, Alejandro Jesús; Li, Yaohang; Chacón, Pablo

    2016-01-01

    Modeling loops is a critical and challenging step in protein modeling and prediction. We have developed a quick online service (http://rcd.chaconlab.org) for ab initio loop modeling combining a coarse-grained conformational search with a full-atom refinement. Our original Random Coordinate Descent (RCD) loop closure algorithm has been greatly improved to enrich the sampling distribution towards near-native conformations. These improvements include a new workflow optimization, MPI-parallelization and fast backbone angle sampling based on neighbor-dependent Ramachandran probability distributions. The server starts by efficiently searching the vast conformational space from only the loop sequence information and the environment atomic coordinates. The generated closed loop models are subsequently ranked using a fast distance-orientation dependent energy filter. Top ranked loops are refined with the Rosetta energy function to obtain accurate all-atom predictions that can be interactively inspected in an user-friendly web interface. Using standard benchmarks, the average root mean squared deviation (RMSD) is 0.8 and 1.4 Å for 8 and 12 residues loops, respectively, in the challenging modeling scenario in where the side chains of the loop environment are fully remodeled. These results are not only very competitive compared to those obtained with public state of the art methods, but also they are obtained ∼10-fold faster. PMID:27151199

  10. Transporting particulate material

    DOEpatents

    Aldred, Derek Leslie; Rader, Jeffrey A.; Saunders, Timothy W.

    2011-08-30

    A material transporting system comprises a material transporting apparatus (100) including a material transporting apparatus hopper structure (200, 202), which comprises at least one rotary transporting apparatus; a stationary hub structure (900) constraining and assisting the at least one rotary transporting apparatus; an outlet duct configuration (700) configured to permit material to exit therefrom and comprising at least one diverging portion (702, 702'); an outlet abutment configuration (800) configured to direct material to the outlet duct configuration; an outlet valve assembly from the material transporting system venting the material transporting system; and a moving wall configuration in the material transporting apparatus capable of assisting the material transporting apparatus in transporting material in the material transporting system. Material can be moved from the material transporting apparatus hopper structure to the outlet duct configuration through the at least one rotary transporting apparatus, the outlet abutment configuration, and the outlet valve assembly.

  11. Transporting Handicapped Students.

    ERIC Educational Resources Information Center

    Turner, Dayton Ray

    The book presents guidelines for adaptive transportation measures for handicapped students. Part 1 considers the transportation cycle as a means to evaluate individual student competencies at all logical points during the transportation experience. The transportation cycle is reviewed from deciding to transport the student to gaining access to…

  12. A FAST POLYNOMIAL TRANSFORM PROGRAM WITH A MODULARIZED STRUCTURE

    NASA Technical Reports Server (NTRS)

    Truong, T. K.

    1994-01-01

    This program utilizes a fast polynomial transformation (FPT) algorithm applicable to two-dimensional mathematical convolutions. Two-dimensional convolution has many applications, particularly in image processing. Two-dimensional cyclic convolutions can be converted to a one-dimensional convolution in a polynomial ring. Traditional FPT methods decompose the one-dimensional cyclic polynomial into polynomial convolutions of different lengths. This program will decompose a cyclic polynomial into polynomial convolutions of the same length. Thus, only FPTs and Fast Fourier Transforms of the same length are required. This modular approach can save computational resources. To further enhance its appeal, the program is written in the transportable 'C' language. The steps in the algorithm are: 1) formulate the modulus reduction equations, 2) calculate the polynomial transforms, 3) multiply the transforms using a generalized fast Fourier transformation, 4) compute the inverse polynomial transforms, and 5) reconstruct the final matrices using the Chinese remainder theorem. Input to this program is comprised of the row and column dimensions and the initial two matrices. The matrices are printed out at all steps, ending with the final reconstruction. This program is written in 'C' for batch execution and has been implemented on the IBM PC series of computers under DOS with a central memory requirement of approximately 18K of 8 bit bytes. This program was developed in 1986.

  13. Electrical studies on silver based fast ion conducting glassy materials

    SciTech Connect

    Rao, B. Appa Kumar, E. Ramesh Kumari, K. Rajani Bhikshamaiah, G.

    2014-04-24

    Among all the available fast ion conductors, silver based glasses exhibit high conductivity. Further, glasses containing silver iodide enhances fast ion conducting behavior at room temperature. Glasses of various compositions of silver based fast ion conductors in the AgI−Ag{sub 2}O−[(1−x)B{sub 2}O{sub 3}−xTeO{sub 2}] (x=0 to1 mol% in steps of 0.2) glassy system have been prepared by melt quenching method. The glassy nature of the compounds has been confirmed by X-ray diffraction. The electrical conductivity (AC) measurements have been carried out in the frequency range of 1 KHz–3MHz by Impedance Analyzer in the temperature range 303–423K. The DC conductivity measurements were also carried out in the temperature range 300–523K. From both AC and DC conductivity studies, it is found that the conductivity increases and activation energy decreases with increasing the concentration of TeO{sub 2} as well as with temperature. The conductivity of the present glass system is found to be of the order of 10{sup −2} S/cm at room temperature. The ionic transport number of these glasses is found to be 0.999 indicating that these glasses can be used as electrolyte in batteries.

  14. Research on Fast-Doppler-Broadening of neutron cross sections

    SciTech Connect

    Li, S.; Wang, K.; Yu, G.

    2012-07-01

    A Fast-Doppler-Broadening method is developed in this work to broaden Continuous Energy neutron cross-sections for Monte Carlo calculations. Gauss integration algorithm and parallel computing are implemented in this method, which is unprecedented in the history of cross section processing. Compared to the traditional code (NJOY, SIGMA1, etc.), the new Fast-Doppler-Broadening method shows a remarkable speedup with keeping accuracy. The purpose of using Gauss integration is to avoid complex derivation of traditional broadening formula and heavy load of computing complementary error function that slows down the Doppler broadening process. The OpenMP environment is utilized in parallel computing which can take full advantage of modern multi-processor computers. Combination of the two can reduce processing time of main actinides (such as {sup 238}U, {sup 235}U) to an order of magnitude of 1{approx}2 seconds. This new method is fast enough to be applied to Online Doppler broadening. It can be combined or coupled with Monte Carlo transport code to solve temperature dependent problems and neutronics-thermal hydraulics coupled scheme which is a big challenge for the conventional NJOY-MCNP system. Examples are shown to determine the efficiency and relative errors compared with the NJOY results. A Godiva Benchmark is also used in order to test the ACE libraries produced by the new method. (authors)

  15. Characterization of the fast electrons distribution produced in a high intensity laser target interaction

    SciTech Connect

    Westover, B.; Chen, C. D.; Patel, P. K.; McLean, H.; Beg, F. N.

    2014-03-15

    Experiments on the Titan laser (∼150 J, 0.7 ps, 2 × 10{sup 20} W cm{sup −2}) at the Lawrence Livermore National Laboratory were carried out in order to study the properties of fast electrons produced by high-intensity, short pulse laser interacting with matter under conditions relevant to Fast Ignition. Bremsstrahlung x-rays produced by these fast electrons were measured by a set of compact filter-stack based x-ray detectors placed at three angles with respect to the target. The measured bremsstrahlung signal allows a characterization of the fast electron beam spectrum, conversion efficiency of laser energy into fast electron kinetic energy and angular distribution. A Monte Carlo code Integrated Tiger Series was used to model the bremsstrahlung signal and infer a laser to fast electron conversion efficiency of 30%, an electron slope temperature of about 2.2 MeV, and a mean divergence angle of 39°. Simulations were also performed with the hybrid transport code ZUMA which includes fields in the target. In this case, a conversion efficiency of laser energy to fast electron energy of 34% and a slope temperature between 1.5 MeV and 4 MeV depending on the angle between the target normal direction and the measuring spectrometer are found. The observed temperature of the bremsstrahlung spectrum, and therefore the inferred electron spectrum are found to be angle dependent.

  16. Hydrodynamic assembly for Fast Ignition

    NASA Astrophysics Data System (ADS)

    Tabak, Max; Clark, Daniel; Town, Richard; Hatchett, Stephen

    2007-11-01

    We present directly and indirectly driven implosion designs for Fast Ignition. Directly driven designs using various laser illumination wavelengths are described. We compare these designs with simple hydrodynamic efficiency models. Capsules illuminated with less than 1 MJ of light with perfect zooming at low intensity and low contrast ratio in power can assemble 4 mg of fuel to column density in excess of 3 g/cm^2. We contrast these designs with more optimized designs that lead to Guderley-style self similar implosions. Indirectly driven capsules absorbing 75 kJ of xrays can assemble 0.7 mg to column density 2.7 g/cm^2 in 1D simulations. We describe 2-D simulations including both capsules and attached cones driven by radiation. We describe issues in assembling fuel near the cone tip and cone disruption.

  17. On fast reactor kinetics studies

    SciTech Connect

    Seleznev, E. F.; Belov, A. A.; Matveenko, I. P.; Zhukov, A. M.; Raskach, K. F.

    2012-07-01

    The results and the program of fast reactor core time and space kinetics experiments performed and planned to be performed at the IPPE critical facility is presented. The TIMER code was taken as computation support of the experimental work, which allows transient equations to be solved in 3-D geometry with multi-group diffusion approximation. The number of delayed neutron groups varies from 6 to 8. The code implements the solution of both transient neutron transfer problems: a direct one, where neutron flux density and its derivatives, such as reactor power, etc, are determined at each time step, and an inverse one for the point kinetics equation form, where such a parameter as reactivity is determined with a well-known reactor power time variation function. (authors)

  18. Fast data parallel polygon rendering

    SciTech Connect

    Ortega, F.A.; Hansen, C.D.

    1993-09-01

    This paper describes a parallel method for polygonal rendering on a massively parallel SIMD machine. This method, based on a simple shading model, is targeted for applications which require very fast polygon rendering for extremely large sets of polygons such as is found in many scientific visualization applications. The algorithms described in this paper are incorporated into a library of 3D graphics routines written for the Connection Machine. The routines are implemented on both the CM-200 and the CM-5. This library enables a scientists to display 3D shaded polygons directly from a parallel machine without the need to transmit huge amounts of data to a post-processing rendering system.

  19. Fast Steerable Principal Component Analysis

    PubMed Central

    Zhao, Zhizhen; Shkolnisky, Yoel; Singer, Amit

    2016-01-01

    Cryo-electron microscopy nowadays often requires the analysis of hundreds of thousands of 2-D images as large as a few hundred pixels in each direction. Here, we introduce an algorithm that efficiently and accurately performs principal component analysis (PCA) for a large set of 2-D images, and, for each image, the set of its uniform rotations in the plane and their reflections. For a dataset consisting of n images of size L × L pixels, the computational complexity of our algorithm is O(nL3 + L4), while existing algorithms take O(nL4). The new algorithm computes the expansion coefficients of the images in a Fourier–Bessel basis efficiently using the nonuniform fast Fourier transform. We compare the accuracy and efficiency of the new algorithm with traditional PCA and existing algorithms for steerable PCA. PMID:27570801

  20. First results on fast baking

    NASA Astrophysics Data System (ADS)

    Visentin, B.; Gasser, Y.; Charrier, J. P.

    2006-07-01

    High gradient performances of bulk niobium cavities go through a low-temperature baking during one or two days, the temperature parameter is adjusted in a narrow tuning range around 110 or 120 °C. With such treatment, the intrinsic quality factor Q0 is improved at high fields. Assuming the oxygen diffusion is involved in this phenomenon, we have developed the “fast baking” (145 °C/3 h) as an alternative method. Similar results have been achieved with this method compared to standard baking. Consequently, for the first time, a link between oxygen diffusion and high field Q-slope has been demonstrated. Furthermore, this method open the way to a simpler and better baking procedure for the large-scale cavity production due to: time reduction and possibility to combine baking and drying during cavity preparation.

  1. Rotor for centrifugal fast analyzers

    DOEpatents

    Lee, N.E.

    1984-01-01

    The invention is an improved photometric analyzer of the rotary cuvette type, the analyzer incorporating a multicuvette rotor of novel design. The rotor (a) is leaktight, (b) permits operation in the 90/sup 0/ and 180/sup 0/ excitation modes, (c) is compatible with extensively used Centrifugal Fast Analyzers, and (d) can be used thousands of times. The rotor includes an assembly comprising a top plate, a bottom plate, and a central plate, the rim of the central plate being formed with circumferentially spaced indentations. A uv-transmitting ring is sealably affixed to the indented rim to define with the indentations an array of cuvettes. The ring serves both as a sealing means and an end window for the cuvettes.

  2. Rotor for centrifugal fast analyzers

    DOEpatents

    Lee, Norman E.

    1985-01-01

    The invention is an improved photometric analyzer of the rotary cuvette type, the analyzer incorporating a multicuvette rotor of novel design. The rotor (a) is leaktight, (b) permits operation in the 90.degree. and 180.degree. excitation modes, (c) is compatible with extensively used Centrifugal Fast Analyzers, and (d) can be used thousands of times. The rotor includes an assembly comprising a top plate, a bottom plate, and a central plate, the rim of the central plate being formed with circumferentially spaced indentations. A UV-transmitting ring is sealably affixed to the indented rim to define with the indentations an array of cuvettes. The ring serves both as a sealing means and an end window for the cuvettes.

  3. Fast Randomized STDMA Link Scheduling

    NASA Astrophysics Data System (ADS)

    Gomez, Sergio; Gras, Oriol; Friderikos, Vasilis

    In this paper a fast randomized parallel link swap based packing (RSP) algorithm for timeslot allocation in a spatial time division multiple access (STDMA) wireless mesh network is presented. The proposed randomized algorithm extends several greedy scheduling algorithms that utilize the physical interference model by applying a local search that leads to a substantial improvement in the spatial timeslot reuse. Numerical simulations reveal that compared to previously scheduling schemes the proposed randomized algorithm can achieve a performance gain of up to 11%. A significant benefit of the proposed scheme is that the computations can be parallelized and therefore can efficiently utilize commoditized and emerging multi-core and/or multi-CPU processors.

  4. Fast breeder reactor protection system

    DOEpatents

    van Erp, J.B.

    1973-10-01

    Reactor protection is provided for a liquid-metal-fast breeder reactor core by measuring the coolant outflow temperature from each of the subassemblies of the core. The outputs of the temperature sensors from a subassembly region of the core containing a plurality of subassemblies are combined in a logic circuit which develops a scram alarm if a predetermined number of the sensors indicate an over temperature condition. The coolant outflow from a single subassembly can be mixed with the coolant outflow from adjacent subassemblies prior to the temperature sensing to increase the sensitivity of the protection system to a single subassembly failure. Coherence between the sensors can be required to discriminate against noise signals. (Official Gazette)

  5. Automatic differentiation: Obtaining fast and reliable derivatives -- fast

    SciTech Connect

    Bischof, C.H.; Khademi, P.M.; Pusch, G.; Carle, A.

    1994-12-31

    In this paper, the authors introduce automatic differentiation as a method for computing derivatives of large computer codes. After a brief discussion of methods of differentiating codes, they review automatic differentiation and introduce the ADIFOR (Automatic DIfferentiation of FORtran) tool. They highlight some applications of ADIFOR to large industrial and scientific codes (groundwater transport, CFD airfoil design, and sensitivity-enhanced MM5 mesoscale weather model), and discuss the effectiveness and performance of their approach. Finally, they discuss sparsity in automatic differentiation and introduce the SparsLinC library.

  6. FastBit Reference Manual

    SciTech Connect

    Wu, Kesheng

    2007-08-02

    An index in a database system is a data structure that utilizes redundant information about the base data to speed up common searching and retrieval operations. Most commonly used indexes are variants of B-trees, such as B+-tree and B*-tree. FastBit implements a set of alternative indexes call compressed bitmap indexes. Compared with B-tree variants, these indexes provide very efficient searching and retrieval operations by sacrificing the efficiency of updating the indexes after the modification of an individual record. In addition to the well-known strengths of bitmap indexes, FastBit has a special strength stemming from the bitmap compression scheme used. The compression method is called the Word-Aligned Hybrid (WAH) code. It reduces the bitmap indexes to reasonable sizes and at the same time allows very efficient bitwise logical operations directly on the compressed bitmaps. Compared with the well-known compression methods such as LZ77 and Byte-aligned Bitmap code (BBC), WAH sacrifices some space efficiency for a significant improvement in operational efficiency. Since the bitwise logical operations are the most important operations needed to answer queries, using WAH compression has been shown to answer queries significantly faster than using other compression schemes. Theoretical analyses showed that WAH compressed bitmap indexes are optimal for one-dimensional range queries. Only the most efficient indexing schemes such as B+-tree and B*-tree have this optimality property. However, bitmap indexes are superior because they can efficiently answer multi-dimensional range queries by combining the answers to one-dimensional queries.

  7. Heterogeneous Recycling in Fast Reactors

    SciTech Connect

    Forget, Benoit; Pope, Michael; Piet, Steven J.; Driscoll, Michael

    2012-07-30

    Current sodium fast reactor (SFR) designs have avoided the use of depleted uranium blankets over concerns of creating weapons grade plutonium. While reducing proliferation risks, this restrains the reactor design space considerably. This project will analyze various blanket and transmutation target configurations that could broaden the design space while still addressing the non-proliferation issues. The blanket designs will be assessed based on the transmutation efficiency of key minor actinide (MA) isotopes and also on mitigation of associated proliferation risks. This study will also evaluate SFR core performance under different scenarios in which depleted uranium blankets are modified to include minor actinides with or without moderators (e.g. BeO, MgO, B4C, and hydrides). This will be done in an effort to increase the sustainability of the reactor and increase its power density while still offering a proliferation resistant design with the capability of burning MA waste produced from light water reactors (LWRs). Researchers will also analyze the use of recycled (as opposed to depleted) uranium in the blankets. The various designs will compare MA transmutation efficiency, plutonium breeding characteristics, proliferation risk, shutdown margins and reactivity coefficients with a current reference sodium fast reactor design employing homogeneous recycling. The team will also evaluate the out-of-core accumulation and/or burn-down rates of MAs and plutonium isotopes on a cycle-by-cycle basis. This cycle-by-cycle information will be produced in a format readily usable by the fuel cycle systems analysis code, VISION, for assessment of the sustainability of the deployment scenarios.

  8. Should Type 1 diabetics fast in Ramadan.

    PubMed

    Mohsin, Fauzia; Azad, Kishwar; Zabeen, Bedowra; Tayyeb, Samin; Baki, Abdul; Nahar, Nazmun

    2015-05-01

    Fasting during the holy month of Ramadan is obligatory for all healthy adult and adolescent Muslims from the age of 12 years. This involves abstaining from eating or drinking from early dawn (Suhur/Sehri) till sunset (Iftar).Fasting is not meant to create excessive hardships or impart any adverse effect to the Muslim individual. As such, Islam has exempted certain categories of people from fasting including young children, travelers, the sick, the elderly,and pregnant and lactating women. According to expert opinion, people with type 1 diabetes who fast during Ramadan are at very high risk of metabolic deterioration. However, some recent studies have demonstrated that individuals with type 1 diabetes who are otherwise healthy and stable, can fast during Ramadan provided they comply with the Ramadan focused management plan and are under close professional supervision. This article discusses how to assess, counsel, monitor and manage people with type 1 diabetes who wish to fast during Ramadan.

  9. Study of plasma heating induced by fast electrons

    SciTech Connect

    Morace, A.; Batani, D.; Redaelli, R.; Magunov, A.; Fourment, C.; Santos, J. J.; Malka, G.; Boscheron, A.; Nazarov, W.; Vinci, T.; Okano, Y.; Inubushi, Y.; Nishimura, H.; Flacco, A.; Spindloe, C.; Tolley, M.

    2009-12-15

    We studied the induced plasma heating in three different kinds of targets: mass limited, foam targets, and large mass targets. The experiment was performed at Alise Laser Facility of CEA/CESTA. The laser system emitted a approx1 ps pulse with approx10 J energy at a wavelength of approx1 {mu}m. Mass limited targets had three layers with thicknesses of 10 {mu}m C{sub 8}H{sub 8}, 1 {mu}m C{sub 8}H{sub 7}Cl, and 10 {mu}m C{sub 8}H{sub 8} with size of 100x100 {mu}m{sup 2}. Detailed spectroscopic analysis of x rays emitted from the Cl tracer showed that it was possible to heat up the plasma from mass limited targets to a temperature of approx250 eV with density of approx10{sup 21} cm{sup -3}. The plasma heating is only produced by fast electron transport in the target, being the 10 {mu}m C{sub 8}H{sub 8} overcoating thick enough to prevent any possible direct irradiation of the tracer layer even taking into account mass-ablation due to the prepulse. These results demonstrate that with mass limited targets, it is possible to generate a plasma heated up to several hundreds eV. It is also very important for research concerning high energy density phenomena and for fast ignition (in particular for the study of fast electrons transport and induced heating).

  10. Magnetic-field-induced surface transport on laser-irradiated foils

    NASA Astrophysics Data System (ADS)

    Forslund, D. W.; Brackbill, J. U.

    1982-06-01

    Electrons heated by absorption of laser energy are shown to generate intense magnetic fields which rapidly spread from the edge of the laser spot along the target surface. The fields convectively transport hot electrons and confine a major fraction of the deposited laser energy in the corona. Eventually, this energy is lost to fast-ion blowoff or deposited at large distances from the spot. This model qualitatively explains many experimental observations of thermal-transport inhibition and fast-ion loss.

  11. Fasting: molecular mechanisms and clinical applications.

    PubMed

    Longo, Valter D; Mattson, Mark P

    2014-02-01

    Fasting has been practiced for millennia, but, only recently, studies have shed light on its role in adaptive cellular responses that reduce oxidative damage and inflammation, optimize energy metabolism, and bolster cellular protection. In lower eukaryotes, chronic fasting extends longevity, in part, by reprogramming metabolic and stress resistance pathways. In rodents intermittent or periodic fasting protects against diabetes, cancers, heart disease, and neurodegeneration, while in humans it helps reduce obesity, hypertension, asthma, and rheumatoid arthritis. Thus, fasting has the potential to delay aging and help prevent and treat diseases while minimizing the side effects caused by chronic dietary interventions. PMID:24440038

  12. Safer staining method for acid fast bacilli.

    PubMed Central

    Ellis, R C; Zabrowarny, L A

    1993-01-01

    To develop a method for staining acid fast bacilli which excluded highly toxic phenol from the staining solution. A lipophilic agent, a liquid organic detergent, LOC High Studs, distributed by Amway, was substituted. The acid fast bacilli stained red; nuclei, cytoplasm, and cytoplasmic elements stained blue on a clear background. These results compare very favourably with acid fast bacilli stained by the traditional method. Detergents are efficient lipophilic agents and safer to handle than phenol. The method described here stains acid fast bacilli as efficiently as traditional carbol fuchsin methods. LOC High Suds is considerably cheaper than phenol. Images PMID:7687254

  13. Safer staining method for acid fast bacilli.

    PubMed

    Ellis, R C; Zabrowarny, L A

    1993-06-01

    To develop a method for staining acid fast bacilli which excluded highly toxic phenol from the staining solution. A lipophilic agent, a liquid organic detergent, LOC High Studs, distributed by Amway, was substituted. The acid fast bacilli stained red; nuclei, cytoplasm, and cytoplasmic elements stained blue on a clear background. These results compare very favourably with acid fast bacilli stained by the traditional method. Detergents are efficient lipophilic agents and safer to handle than phenol. The method described here stains acid fast bacilli as efficiently as traditional carbol fuchsin methods. LOC High Suds is considerably cheaper than phenol.

  14. Relationship of attitudes toward fast food and frequency of fast-food intake in adults.

    PubMed

    Dave, Jayna M; An, Lawrence C; Jeffery, Robert W; Ahluwalia, Jasjit S

    2009-06-01

    The purpose of the study was to examine the association between attitudes toward fast food and the frequency of fast-food intake in adults. This study is a cross-sectional evaluation of random digit-dial telephone surveys to identify patterns of eating away from home and attitudes toward it. Participants included 530 adults (94% white, 65% women, 70% married, 42% with college educated). Attitudes toward fast food was measured using an 11-item, 4-dimensional scale: perceived convenience of fast food (alpha=0.56); fast food is fun and social (alpha=0.55); fast food perceived as unhealthful (alpha=0.45); and dislike toward cooking (alpha=0.52). Frequency of fast-food intake was found to be significantly associated with age (odds ratios (OR)=0.981, P=0.001), gender (men>women), and marital status of the participants (single>married/partnered and divorced/separated/widowed). Additionally, frequency of fast-food intake was also found to be significantly associated with perceived convenience of fast food (OR=1.162, P<0.001) and dislike toward cooking (OR=1.119, P<0.001) but not with perceived unhealthfulness of fast food (OR=0.692, P=0.207). These findings suggest public education regarding the unhealthfulness of fast food may not influence fast food consumption. Interventions targeting the issue of convenience and quick or efficient preparation of nutritious alternatives to fast food could be more promising. PMID:19247277

  15. Primitive layered gabbros from fast-spreading lower oceanic crust

    NASA Astrophysics Data System (ADS)

    Gillis, Kathryn M.; Snow, Jonathan E.; Klaus, Adam; Abe, Natsue; Adrião, Álden B.; Akizawa, Norikatsu; Ceuleneer, Georges; Cheadle, Michael J.; Faak, Kathrin; Falloon, Trevor J.; Friedman, Sarah A.; Godard, Marguerite; Guerin, Gilles; Harigane, Yumiko; Horst, Andrew J.; Hoshide, Takashi; Ildefonse, Benoit; Jean, Marlon M.; John, Barbara E.; Koepke, Juergen; Machi, Sumiaki; Maeda, Jinichiro; Marks, Naomi E.; McCaig, Andrew M.; Meyer, Romain; Morris, Antony; Nozaka, Toshio; Python, Marie; Saha, Abhishek; Wintsch, Robert P.

    2014-01-01

    Three-quarters of the oceanic crust formed at fast-spreading ridges is composed of plutonic rocks whose mineral assemblages, textures and compositions record the history of melt transport and crystallization between the mantle and the sea floor. Despite the importance of these rocks, sampling them in situ is extremely challenging owing to the overlying dykes and lavas. This means that models for understanding the formation of the lower crust are based largely on geophysical studies and ancient analogues (ophiolites) that did not form at typical mid-ocean ridges. Here we describe cored intervals of primitive, modally layered gabbroic rocks from the lower plutonic crust formed at a fast-spreading ridge, sampled by the Integrated Ocean Drilling Program at the Hess Deep rift. Centimetre-scale, modally layered rocks, some of which have a strong layering-parallel foliation, confirm a long-held belief that such rocks are a key constituent of the lower oceanic crust formed at fast-spreading ridges. Geochemical analysis of these primitive lower plutonic rocks--in combination with previous geochemical data for shallow-level plutonic rocks, sheeted dykes and lavas--provides the most completely constrained estimate of the bulk composition of fast-spreading oceanic crust so far. Simple crystallization models using this bulk crustal composition as the parental melt accurately predict the bulk composition of both the lavas and the plutonic rocks. However, the recovered plutonic rocks show early crystallization of orthopyroxene, which is not predicted by current models of melt extraction from the mantle and mid-ocean-ridge basalt differentiation. The simplest explanation of this observation is that compositionally diverse melts are extracted from the mantle and partly crystallize before mixing to produce the more homogeneous magmas that erupt.

  16. Primitive layered gabbros from fast-spreading lower oceanic crust.

    PubMed

    Gillis, Kathryn M; Snow, Jonathan E; Klaus, Adam; Abe, Natsue; Adrião, Alden B; Akizawa, Norikatsu; Ceuleneer, Georges; Cheadle, Michael J; Faak, Kathrin; Falloon, Trevor J; Friedman, Sarah A; Godard, Marguerite; Guerin, Gilles; Harigane, Yumiko; Horst, Andrew J; Hoshide, Takashi; Ildefonse, Benoit; Jean, Marlon M; John, Barbara E; Koepke, Juergen; Machi, Sumiaki; Maeda, Jinichiro; Marks, Naomi E; McCaig, Andrew M; Meyer, Romain; Morris, Antony; Nozaka, Toshio; Python, Marie; Saha, Abhishek; Wintsch, Robert P

    2014-01-01

    Three-quarters of the oceanic crust formed at fast-spreading ridges is composed of plutonic rocks whose mineral assemblages, textures and compositions record the history of melt transport and crystallization between the mantle and the sea floor. Despite the importance of these rocks, sampling them in situ is extremely challenging owing to the overlying dykes and lavas. This means that models for understanding the formation of the lower crust are based largely on geophysical studies and ancient analogues (ophiolites) that did not form at typical mid-ocean ridges. Here we describe cored intervals of primitive, modally layered gabbroic rocks from the lower plutonic crust formed at a fast-spreading ridge, sampled by the Integrated Ocean Drilling Program at the Hess Deep rift. Centimetre-scale, modally layered rocks, some of which have a strong layering-parallel foliation, confirm a long-held belief that such rocks are a key constituent of the lower oceanic crust formed at fast-spreading ridges. Geochemical analysis of these primitive lower plutonic rocks--in combination with previous geochemical data for shallow-level plutonic rocks, sheeted dykes and lavas--provides the most completely constrained estimate of the bulk composition of fast-spreading oceanic crust so far. Simple crystallization models using this bulk crustal composition as the parental melt accurately predict the bulk composition of both the lavas and the plutonic rocks. However, the recovered plutonic rocks show early crystallization of orthopyroxene, which is not predicted by current models of melt extraction from the mantle and mid-ocean-ridge basalt differentiation. The simplest explanation of this observation is that compositionally diverse melts are extracted from the mantle and partly crystallize before mixing to produce the more homogeneous magmas that erupt.

  17. A beam transport system for an intense He(-) beam source.

    PubMed

    Tanaka, N; Kikuchi, M; Nagamura, T; Sugawara, H; Takeuchi, S; Kobuchi, T; Okamoto, A; Shinto, K; Kitajima, S; Sasao, M; Wada, M

    2008-02-01

    We have been developing a test stand for fast He(0) beam production. One of the major issues is how to transport effectively the He(+) and He(-) beams from which the He(0) beam is produced. The beam should be focused in two transverse focal points, the center of the charge exchange cell and the electrostatic accelerator. We studied the beam transport system and effect of space charge neutralization in the test stand by experiments and calculation.

  18. Mitochondrial metabolic suppression in fasting and daily torpor: consequences for reactive oxygen species production.

    PubMed

    Brown, Jason C L; Staples, James F

    2011-01-01

    Abstract Daily torpor results in an ∼70% decrease in metabolic rate (MR) and a 20%-70% decrease in state 3 (phosphorylating) respiration rate of isolated liver mitochondria in both dwarf Siberian hamsters and mice even when measured at 37°C. This study investigated whether mitochondrial metabolic suppression also occurs in these species during euthermic fasting, when MR decreases significantly but torpor is not observed. State 3 respiration rate measured at 37°C was 20%-30% lower in euthermic fasted animals when glutamate but not succinate was used as a substrate. This suggests that electron transport chain complex I is inhibited during fasting. We also investigated whether mitochondrial metabolic suppression alters mitochondrial reactive oxygen species (ROS) production. In both torpor and euthermic fasting, ROS production (measured as H(2)O(2) release rate) was lower with glutamate in the presence (but not absence) of rotenone when measured at 37°C, likely reflecting inhibition at or upstream of the complex I ROS-producing site. ROS production with succinate (with rotenone) increased in torpor but not euthermic fasting, reflecting complex II inhibition during torpor only. Finally, mitochondrial ROS production was twofold more temperature sensitive than mitochondrial respiration (as reflected by Q(10) values). These data suggest that electron leak from the mitochondrial electron transport chain, which leads to ROS production, is avoided more efficiently at the lower body temperatures experienced during torpor. PMID:21897084

  19. Axonal Transport Rates In Vivo Are Unaffected by Tau Deletion or Overexpression in Mice

    PubMed Central

    Yuan, Aidong; Kumar, Asok; Peterhoff, Corrinne; Duff, Karen; Nixon, Ralph A.

    2010-01-01

    Elevated tau expression has been proposed as a possible basis for impaired axonal transport in Alzheimer’s disease. To address this hypothesis, we analyzed the movement of pulse radiolabeled proteins in vivo along retinal ganglion cell (RGC) axons of mice that lack tau or overexpress human tau isoforms. Here, we show that the global axonal transport rates of slow and fast transport cargoes in axons are not significantly impaired when tau expression is eliminated or increased. In addition, markers of slow transport (neurofilament light subunit) and fast transport (snap25) do not accumulate in retinas and are distributed normally along optic axons in mice that lack or overexpress tau. Finally, ultrastructural analyses revealed no abnormal accumulations of vesicular organelles or neurofilaments in RGC perikarya or axons in mice overexpressing or lacking tau. These results suggest that tau is not essential for axonal transport and that transport rates in vivo are not significantly affected by substantial fluctuations in tau expression. PMID:18272688

  20. Fast repetition rate (FRR) flasher

    DOEpatents

    Kolber, Zbigniew; Falkowski, Paul

    1997-02-11

    A fast repetition rate (FRR) flasher suitable for high flash photolysis including kinetic chemical and biological analysis. The flasher includes a power supply, a discharge capacitor operably connected to be charged by the power supply, and a flash lamp for producing a series of flashes in response to discharge of the discharge capacitor. A triggering circuit operably connected to the flash lamp initially ionizes the flash lamp. A current switch is operably connected between the flash lamp and the discharge capacitor. The current switch has at least one insulated gate bipolar transistor for switching current that is operable to initiate a controllable discharge of the discharge capacitor through the flash lamp. Control means connected to the current switch for controlling the rate of discharge of the discharge capacitor thereby to effectively keep the flash lamp in an ionized state between Successive discharges of the discharge capacitor. Advantageously, the control means is operable to discharge the discharge capacitor at a rate greater than 10,000 Hz and even up to a rate greater than about 250,000 Hz.

  1. Impulsively generated fast coronal pulsations

    NASA Technical Reports Server (NTRS)

    Edwin, P. M.; Roberts, B.

    1986-01-01

    Rapid oscillations in the corona are discussed from a theoretical standpoint, developing some previous work on ducted, fast magnetoacoustic waves in an inhomogeneous medium. In the theory, impulsively (e.g., flare) generated mhd (magnetohydrodynamic) waves are ducted by regions of low Alfven speed (high density) such as coronal loops. Wave propagation in such ducts is strongly dispersive and closely akin to the behavior of Love waves in seismology, Pekeris waves in oceanography and guided waves in fiber optics. Such flare-generated magnetoacoustic waves possess distinctive temporal signatures consisting of periodic, quasi-periodic and decay phases. The quasi-periodic phase possesses the strongest amplitudes and the shortest time scales. Time scales are typically of the order of a second for inhomogeneities (coronal loop width) of 1000 km and Alfven speeds of 1000/kms, and pulse duration times are of tens of seconds. Quasi-periodic signatures have been observed in radio wavelengths for over a decade and more recently by SMM. It is hoped that the theoretical ideas outlined may be successfully related to these observations and thus aid the interpretation of oscillatory signatures recorded by SMM. Such signatures may also provide a diagnostic of coronal conditions. New aspects of the ducted mhd waves, for example their behavior in smoothly varying as opposed to tube-like inhomogeneities, are currently under investigation. The theory is not restricted to loops but applied equally to open field regions.

  2. Isochoric Implosions for Fast Ignition

    NASA Astrophysics Data System (ADS)

    Clark, Daniel; Tabak, Max

    2006-10-01

    Various gain models have shown the potentially great advantages of Fast Ignition (FI) Inertial Confinement Fusion (ICF) over its conventional hotspot ignition counterpart. These gain models, however, all assume nearly uniform-density fuel assemblies. By contrast, typical ICF implosions yield hollowed fuel assemblies with a high-density shell of fuel surrounding a low-density, high-pressure hotspot. To realize fully the advantages of FI, then, an alternative implosion design must be found which yields nearly isochoric fuel assemblies without substantial hotspots. Here, it is shown that a self-similar spherical implosion of the type originally studied by Guderley [Luftfahrtforschung 19, 302 (1942)] may be employed to yield precisely such quasi-isochoric imploded states. The difficulty remains, however, of accessing these self-similarly imploding configurations from initial conditions representing an actual ICF target, namely a uniform, solid-density shell at rest. Furthermore, these specialized implosions must be realized for practicable drive parameters, i.e., accessible peak pressures, shell aspect ratios, etc. An implosion scheme is presented which meets all of these requirements, suggesting the possibility of genuinely isochoric implosions for FI.

  3. [Fast neutron cross section measurements

    SciTech Connect

    Knoll, G.F.

    1992-10-26

    From its inception, the Nuclear Data Project at the University of Michigan has concentrated on two major objectives: (1) to carry out carefully controlled nuclear measurements of the highest possible reliability in support of the national nuclear data program, and (2) to provide an educational opportunity for students with interests in experimental nuclear science. The project has undergone a successful transition from a primary dependence on our photoneutron laboratory to one in which our current research is entirely based on a unique pulsed 14 MeV fast neutron facility. The new experimental facility is unique in its ability to provide nanosecond bursts of 14 MeV neutrons under conditions that are clean'' and as scatter-free as possible, and is the only one of its type currently in operation in the United States. It has been designed and put into operation primarily by graduate students, and has met or exceeded all of its important initial performance goals. We have reached the point of its routine operation, and most of the data are now in hand that will serve as the basis for the first two doctoral dissertations to be written by participating graduate students. Our initial results on double differential neutron cross sections will be presented at the May 1993 Fusion Reactor Technology Workshop. We are pleased to report that, after investing several years in equipment assembly and optimization, the project has now entered its data production'' phase.

  4. Isochoric Implosions for Fast Ignition

    SciTech Connect

    Clark, D S; Tabak, M

    2007-04-04

    Various gain models have shown the potentially great advantages of Fast Ignition (FI) Inertial Confinement Fusion (ICF) over its conventional hot spot ignition counterpart [e.g., S. Atzeni, Phys. Plasmas 6, 3316 (1999); M. Tabak et al., Fusion Sci. & Technology 49, 254 (2006)]. These gain models, however, all assume nearly uniform-density fuel assemblies. In contrast, conventional ICF implosions yield hollowed fuel assemblies with a high-density shell of fuel surrounding a low-density, high-pressure hot spot. Hence, to realize fully the advantages of FI, an alternative implosion design must be found which yields nearly isochoric fuel assemblies without substantial hot spots. Here, it is shown that a self-similar spherical implosion of the type originally studied by Guderley [Luftfahrtforschung 19, 302 (1942)] may be employed to yield precisely such quasi-isochoric imploded states. The difficulty remains, however, of accessing these self-similarly imploding configurations from initial conditions representing an actual ICF target, namely a uniform, solid-density shell at rest. Furthermore, these specialized implosions must be realized for practicable drive parameters and at the scales and energies of interest in ICF. A direct-drive implosion scheme is presented which meets all of these requirements and reaches a nearly isochoric assembled density of 300 g=cm{sup 3} and areal density of 2.4 g=cm{sup 2} using 485 kJ of laser energy.

  5. Fasting: The History, Pathophysiology and Complications

    PubMed Central

    Kerndt, Peter R.; Naughton, James L.; Driscoll, Charles E.; Loxterkamp, David A.

    1982-01-01

    An appreciation of the physiology of fasting is essential to the understanding of therapeutic dietary interventions and the effect of food deprivation in various diseases. The practice of prolonged fasting for political or religious purposes is increasing, and a physician is likely to encounter such circumstances. Early in fasting weight loss is rapid, averaging 0.9 kg per day during the first week and slowing to 0.3 kg per day by the third week; early rapid weight loss is primarily due to negative sodium balance. Metabolically, early fasting is characterized by a high rate of gluconeogenesis with amino acids as the primary substrates. As fasting continues, progressive ketosis develops due to the mobilization and oxidation of fatty acids. As ketone levels rise they replace glucose as the primary energy source in the central nervous system, thereby decreasing the need for gluconeogenesis and sparing protein catabolism. Several hormonal changes occur during fasting, including a fall in insulin and T3 levels and a rise in glucagon and reverse T3 levels. Most studies of fasting have used obese persons and results may not always apply to lean persons. Medical complications seen in fasting include gout and urate nephrolithiasis, postural hypotension and cardiac arrhythmias. ImagesFigure 4. PMID:6758355

  6. Advanced Safeguards Approaches for New Fast Reactors

    SciTech Connect

    Durst, Philip C.; Therios, Ike; Bean, Robert; Dougan, A.; Boyer, Brian; Wallace, Rick L.; Ehinger, Michael H.; Kovacic, Don N.; Tolk, K.

    2007-12-15

    This third report in the series reviews possible safeguards approaches for new fast reactors in general, and the ABR in particular. Fast-neutron spectrum reactors have been used since the early 1960s on an experimental and developmental level, generally with fertile blanket fuels to “breed” nuclear fuel such as plutonium. Whether the reactor is designed to breed plutonium, or transmute and “burn” actinides depends mainly on the design of the reactor neutron reflector and the whether the blanket fuel is “fertile” or suitable for transmutation. However, the safeguards issues are very similar, since they pertain mainly to the receipt, shipment and storage of fresh and spent plutonium and actinide-bearing “TRU”-fuel. For these reasons, the design of existing fast reactors and details concerning how they have been safeguarded were studied in developing advanced safeguards approaches for the new fast reactors. In this regard, the design of the Experimental Breeder Reactor-II “EBR-II” at the Idaho National Laboratory (INL) was of interest, because it was designed as a collocated fast reactor with a pyrometallurgical reprocessing and fuel fabrication line – a design option being considered for the ABR. Similarly, the design of the Fast Flux Facility (FFTF) on the Hanford Site was studied, because it was a successful prototype fast reactor that ran for two decades to evaluate fuels and the design for commercial-scale fast reactors.

  7. Research Program of a Super Fast Reactor

    SciTech Connect

    Oka, Yoshiaki; Ishiwatari, Yuki; Liu, Jie; Terai, Takayuki; Nagasaki, Shinya; Muroya, Yusa; Abe, Hiroaki; Akiba, Masato; Akimoto, Hajime; Okumura, Keisuke; Akasaka, Naoaki; GOTO, Shoji

    2006-07-01

    Research program of a supercritical-pressure light water cooled fast reactor (Super Fast Reactor) is funded by MEXT (Ministry of Education, Culture, Sports, Science and Technology) in December 2005 as one of the research programs of Japanese NERI (Nuclear Energy Research Initiative). It consists of three programs. (1) development of Super Fast Reactor concept; (2) thermal-hydraulic experiments; (3) material developments. The purpose of the concept development is to pursue the advantage of high power density of fast reactor over thermal reactors to achieve economic competitiveness of fast reactor for its deployment without waiting for exhausting uranium resources. Design goal is not breeding, but maximizing reactor power by using plutonium from spent LWR fuel. MOX will be the fuel of the Super Fast Reactor. Thermal-hydraulic experiments will be conducted with HCFC22 (Hydro chlorofluorocarbons) heat transfer loop of Kyushu University and supercritical water loop at JAEA. Heat transfer data including effect of grid spacers will be taken. The critical flow and condensation of supercritical fluid will be studied. The materials research includes the development and testing of austenitic stainless steel cladding from the experience of PNC1520 for LMFBR. Material for thermal insulation will be tested. SCWR (Supercritical-Water Cooled Reactor) of GIF (Generation-4 International Forum) includes both thermal and fast reactors. The research of the Super Fast Reactor will enhance SCWR research and the data base. The research period will be until March 2010. (authors)

  8. Optical imaging of fast, dynamic neurophysiological function.

    SciTech Connect

    Rector, D. M.; Carter, K. M.; Yao, X.; George, J. S.

    2002-01-01

    Fast evoked responses were imaged from rat dorsal medulla and whisker barrel cortex. To investigate the biophysical mechanisms involved, fast optical responses associated with isolated crustacean nerve stimulation were recorded using birefringence and scattered light. Such studies allow optimization of non-invasive imaging techniques being developed for use in humans.

  9. Analytical model for fast-shock ignition

    NASA Astrophysics Data System (ADS)

    Ghasemi, S. A.; Farahbod, A. H.; Sobhanian, S.

    2014-07-01

    A model and its improvements are introduced for a recently proposed approach to inertial confinement fusion, called fast-shock ignition (FSI). The analysis is based upon the gain models of fast ignition, shock ignition and considerations for the fast electrons penetration into the pre-compressed fuel to examine the formation of an effective central hot spot. Calculations of fast electrons penetration into the dense fuel show that if the initial electron kinetic energy is of the order ˜4.5 MeV, the electrons effectively reach the central part of the fuel. To evaluate more realistically the performance of FSI approach, we have used a quasi-two temperature electron energy distribution function of Strozzi (2012) and fast ignitor energy formula of Bellei (2013) that are consistent with 3D PIC simulations for different values of fast ignitor laser wavelength and coupling efficiency. The general advantages of fast-shock ignition in comparison with the shock ignition can be estimated to be better than 1.3 and it is seen that the best results can be obtained for the fuel mass around 1.5 mg, fast ignitor laser wavelength ˜0.3 micron and the shock ignitor energy weight factor about 0.25.

  10. Nutrient quality of fast food kids meals

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Exposure of children to kids’ meals at fast food restaurants is high; however, the nutrient quality of such meals has not been systematically assessed. We assessed the nutrient quality of fast food meals marketed to young children, i.e., "kids meals". The nutrient quality of kids’ meals was assessed...

  11. Differential staining of bacteria: acid fast stain.

    PubMed

    Reynolds, Jackie; Moyes, Rita B; Breakwell, Donald P

    2009-11-01

    Acid-fastness is an uncommon characteristic shared by the genera Mycobacterium (Section 10A) and Nocardia. Because of this feature, this stain is extremely helpful in identification of these bacteria. Although Gram positive, acid-fast bacteria do not take the crystal violet into the wall well, appearing very light purple rather than the deep purple of normal Gram-positive bacteria.

  12. Can Fast and Slow Intelligence Be Differentiated?

    ERIC Educational Resources Information Center

    Partchev, Ivailo; De Boeck, Paul

    2012-01-01

    Responses to items from an intelligence test may be fast or slow. The research issue dealt with in this paper is whether the intelligence involved in fast correct responses differs in nature from the intelligence involved in slow correct responses. There are two questions related to this issue: 1. Are the processes involved different? 2. Are the…

  13. Fast ion JET diagnostics: confinement and losses

    SciTech Connect

    Kiptily, V. G.; Pinches, S. D.; Sharapov, S. E.; Syme, D. B.; Cecconello, M.; Darrow, D.; Hill, K.; Goloborod'ko, V.; Yavorskij, V.; Johnson, T.; Murari, A.; Reich, M.; Gorini, G.; Zoita, V.

    2008-03-12

    A study of magnetically confined fast ions in tokamaks plays an important role in burning plasma research. To reach ignition and steady burning of a reactor plasma an adequate confinement of energetic ions produced by NBI heating, accelerated with ICRF and born in fusion reactions is essential to provide efficient heating of the bulk plasma. Thus, investigation of the fast ion behaviour is an immediate task for present-day large machines, such as JET, in order to understand the main mechanisms of slowing down, redistribution and losses, and to develop optimal plasma scenarios. Today's JET has an enhanced suite of fast ion diagnostics both of confined and lost ions that enable to significantly contribute to this important area of research. Fast ion populations of p, d, t, {sup 3}He and {sup 4}He, made with ICRF, NBI, and fusion reactions have been investigated in experiments on JET with sophisticated diagnostics in conventional and shear-reversed plasmas, exploring a wide range of effects. This paper will introduce to the JET fast-ion diagnostic techniques and will give an overview of recent observations. A synergy of the unique diagnostic set was utilised in JET, and studies of the response of fast ions to MHD modes (e.g. tornado modes, sawtooth crashes), fast {sup 3}He-ions behaviour in shear-reversed plasmas are impressive examples of that. Some results on fast ion losses in JET experiments with various levels of the toroidal field ripple will be demonstrated.

  14. Fast Mapping in Late-Talking Toddlers

    ERIC Educational Resources Information Center

    Weismer, Susan Ellis; Venker, Courtney E.; Evans, Julia L.; Moyle, Maura Jones

    2013-01-01

    This study investigated fast mapping in late-talking (LT) toddlers and toddlers with normal language (NL) development matched on age, nonverbal cognition, and maternal education. The fast-mapping task included novel object labels and familiar words. The LT group scored significantly lower than the NL group on novel word comprehension and…

  15. Fasting during Ramadan in adolescents with diabetes

    PubMed Central

    Zabeen, Bedowra; Tayyeb, Samin; Benarjee, Biplob; Baki, Abdul; Nahar, Jebun; Mohsin, Fauzia; Nahar, Nazmun; Azad, Kishwar

    2014-01-01

    Background: Fasting (Sawm) during Ramadan, one of the five pillars of Islam is obligatory for all healthy adult and adolescent Muslims from the age of 12 years. Some children with diabetes, despite their exemption insist on fasting in Ramadan. We evaluated the safety of fasting among children with type 1 diabetes. Materials and Mathods: A prospective observational study was designed for diabetic children and adolescents who wish to fast during Ramadan 2012. Patients with their caregivers were given intensive education and instructions were provided by diabetic educators, dieticians and physicians on insulin adjustment, home blood glucose monitoring and dietary adjustments prior to Ramadan. Results: A total of 33 children and adolescents were included in this study. Of these, 16 were male and 17 were female. Majority (60.6%) of the patients could complete their fasting during the Ramadan. Patients were divided into two groups, those who completed fasting were considered as Group-I, whereas patients who broke the fast were in Group-ll. Blood glucose, hemoglobin A1c weight, and insulin dose before and after Ramadan in two groups showed no significant difference. Conclusion: Children older than 11 years of age with type 1 diabetes mellitus with conventional twice-a-day regimen can fast safely during Ramadan provided they have proper education and intensive follow-up during Ramadan. PMID:24701429

  16. FAST User's Guide - Updated August 2005

    SciTech Connect

    Jonkman, J. M.; Buhl, M. L. Jr.

    2005-10-01

    The FAST (Fatigue, Aerodynamics, Structures, and Turbulence) Code is a comprehensive aeroelastic simulator capable of predicting both the extreme and fatigue loads of two- and three-bladed horizontal-axis wind turbines (HAWTs). This document covers the features of FAST and outlines its operating procedures.

  17. Fast Mapping Verb Meaning from Argument Structure

    ERIC Educational Resources Information Center

    Johnson, Valerie E.

    2010-01-01

    Purpose: To examine lexical knowledge in children through a fast mapping task. Method: This study compared the performance of 60 African American English-speaking and general American English-speaking children between the ages of 4 and 6 years. They were presented with a comprehension task involving the fast mapping of novel verbs in 4 different…

  18. Analytical model for fast-shock ignition

    SciTech Connect

    Ghasemi, S. A. Farahbod, A. H.; Sobhanian, S.

    2014-07-15

    A model and its improvements are introduced for a recently proposed approach to inertial confinement fusion, called fast-shock ignition (FSI). The analysis is based upon the gain models of fast ignition, shock ignition and considerations for the fast electrons penetration into the pre-compressed fuel to examine the formation of an effective central hot spot. Calculations of fast electrons penetration into the dense fuel show that if the initial electron kinetic energy is of the order ∼4.5 MeV, the electrons effectively reach the central part of the fuel. To evaluate more realistically the performance of FSI approach, we have used a quasi-two temperature electron energy distribution function of Strozzi (2012) and fast ignitor energy formula of Bellei (2013) that are consistent with 3D PIC simulations for different values of fast ignitor laser wavelength and coupling efficiency. The general advantages of fast-shock ignition in comparison with the shock ignition can be estimated to be better than 1.3 and it is seen that the best results can be obtained for the fuel mass around 1.5 mg, fast ignitor laser wavelength ∼0.3  micron and the shock ignitor energy weight factor about 0.25.

  19. Transport induced by mean-eddy interaction: II. Analysis of transport processes

    NASA Astrophysics Data System (ADS)

    Ide, Kayo; Wiggins, Stephen

    2015-03-01

    We present a framework for the analysis of transport processes resulting from the mean-eddy interaction in a flow. The framework is based on the Transport Induced by the Mean-Eddy Interaction (TIME) method presented in a companion paper (Ide and Wiggins, 2014) [1]. The TIME method estimates the (Lagrangian) transport across stationary (Eulerian) boundaries defined by chosen streamlines of the mean flow. Our framework proceeds after first carrying out a sequence of preparatory steps that link the flow dynamics to the transport processes. This includes the construction of the so-called "instantaneous flux" as the Hovmöller diagram. Transport processes are studied by linking the signals of the instantaneous flux field to the dynamical variability of the flow. This linkage also reveals how the variability of the flow contributes to the transport. The spatio-temporal analysis of the flux diagram can be used to assess the efficiency of the variability in transport processes. We apply the method to the double-gyre ocean circulation model in the situation where the Rossby-wave mode dominates the dynamic variability. The spatio-temporal analysis shows that the inter-gyre transport is controlled by the circulating eddy vortices in the fast eastward jet region, whereas the basin-scale Rossby waves have very little impact.

  20. Texture Mapping via Optimal Mass Transport

    PubMed Central

    Dominitz, Ayelet; Tannenbaum, Allen

    2010-01-01

    In this paper, we present a novel method for texture mapping of closed surfaces. Our method is based on the technique of optimal mass transport (also known as the “earth-mover’s metric”). This is a classical problem that concerns determining the optimal way, in the sense of minimal transportation cost, of moving a pile of soil from one site to another. In our context, the resulting mapping is area preserving and minimizes angle distortion in the optimal mass sense. Indeed, we first begin with an angle-preserving mapping (which may greatly distort area) and then correct it using the mass transport procedure derived via a certain gradient flow. In order to obtain fast convergence to the optimal mapping, we incorporate a multiresolution scheme into our flow. We also use ideas from discrete exterior calculus in our computations. PMID:20224137

  1. Development towards a fast ion loss detector for the reversed field pinch

    NASA Astrophysics Data System (ADS)

    Bonofiglo, P. J.; Anderson, J. K.; Almagri, A. F.; Kim, J.; Clark, J.; Capecchi, W.; Sears, S. H.; Egedal, J.

    2016-11-01

    A fast ion loss detector has been constructed and implemented on the Madison Symmetric Torus (MST) to investigate energetic ion losses and transport due to energetic particle and MHD instabilities. The detector discriminates particle orbits solely on pitch and consists of two thin-foil, particle collecting plates that are symmetric with respect to the device aperture. One plate collects fast ion signal, while the second aids in the minimization of background and noise effects. Initial measurements are reported along with suggestions for the next design phase of the detector.

  2. Absorption of thiamine and nicotinic acid in the rat intestine during fasting and immobilization stress

    NASA Technical Reports Server (NTRS)

    Kirilyuk, O. G.; Khmelevskiy, Y. V.

    1980-01-01

    By perfusion of isolated sections of intestine with a solution containing thiamine at a concentration of 3.1 micromole, it was established that thiamine absorption in animals fasted for 72 hours decreased by 28 percent, whereas absorption increased by 12 percent in rats after 24 hour immobilization. After immobilization, absorption of label in the intestinal mucosa increased. Na K ATPase activity in the intestinal mucosa decreased by 10 percent during fasting, and it increased with immobilization of the animals. Activity of Na K ATPase in the intestinal mucosa cells determined the absorption rate of thiamine and nicotinic acid at the level of vitamin transport through the plasma membranes of the enterocytes.

  3. The performance of ENDF/B-V. 2 nuclear data for fast reactor calculations

    SciTech Connect

    Atkinson, C.A.; Collins, P.J.

    1987-01-01

    Calculations with ENDF/B-V.2 data have been made for twenty-five fast-spectrum integral assemblies covering a wide range of sizes and compositions. Analysis was done by transport codes with refined cross section processing methods and detailed reactor modelling. The predictions of fission rate distributions and control rod worths were emphasized for the more prototypic benchmark cores. The results show considerable improvements in agreement with experiment compared with analysis using ENDF/B-IV data, but it is apparent that significant errors remain for fast reactor design calculations.

  4. Fast-Food Consumption, Diet Quality, and Neighborhood Exposure to Fast Food

    PubMed Central

    Diez Roux, Ana V.; Nettleton, Jennifer A.; Jacobs, David R.; Franco, Manuel

    2009-01-01

    The authors examined associations among fast-food consumption, diet, and neighborhood fast-food exposure by using 2000–2002 Multi-Ethnic Study of Atherosclerosis data. US participants (n = 5,633; aged 45–84 years) reported usual fast-food consumption (never, <1 time/week, or ≥1 times/week) and consumption near home (yes/no). Healthy diet was defined as scoring in the top quintile of the Alternate Healthy Eating Index or bottom quintile of a Western-type dietary pattern. Neighborhood fast-food exposure was measured by densities of fast-food outlets, participant report, and informant report. Separate logistic regression models were used to examine associations of fast-food consumption and diet; fast-food exposure and consumption near home; and fast-food exposure and diet adjusted for site, age, sex, race/ethnicity, education, and income. Those never eating fast food had a 2–3-times higher odds of having a healthy diet versus those eating fast food ≥1 times/week, depending on the dietary measure. For every standard deviation increase in fast-food exposure, the odds of consuming fast food near home increased 11%–61% and the odds of a healthy diet decreased 3%–17%, depending on the model. Results show that fast-food consumption and neighborhood fast-food exposure are associated with poorer diet. Interventions that reduce exposure to fast food and/or promote individual behavior change may be helpful. PMID:19429879

  5. Fast Pyrolysis of Wood for Biofuels: Spatiotemporally Resolved Diffuse Reflectance In situ Spectroscopy of Particles.

    PubMed

    Paulsen, Alex D; Hough, Blake R; Williams, C Luke; Teixeira, Andrew R; Schwartz, Daniel T; Pfaendtner, Jim; Dauenhauer, Paul J

    2014-02-20

    Fast pyrolysis of woody biomass is a promising process capable of producing renewable transportation fuels to replace gasoline, diesel, and chemicals currently derived from nonrenewable sources. However, biomass pyrolysis is not yet economically viable and requires significant optimization before it can contribute to the existing oil-based transportation system. One method of optimization uses detailed kinetic models for predicting the products of biomass fast pyrolysis, which serve as the basis for the design of pyrolysis reactors capable of producing the highest value products. The goal of this work is to improve upon current pyrolysis models, usually derived from experiments with low heating rates and temperatures, by developing models that account for both transport and pyrolysis decomposition kinetics at high heating rates and high temperatures (>400 °C). A new experimental technique is proposed herein: spatiotemporally resolved diffuse reflectance in situ spectroscopy of particles (STR-DRiSP), which is capable of measuring biomass composition during fast pyrolysis with high spatial (10 μm) and temporal (1 ms) resolution. Compositional data were compared with a comprehensive 2D single-particle model, which incorporated a multistep, semiglobal reaction mechanism, prescribed particle shrinkage, and thermophysical properties that varied with temperature, composition, and orientation. The STR-DRiSP technique can be used to determine the transport-limited kinetic parameters of biomass decomposition for a wide variety of biomass feedstocks. PMID:24678023

  6. Fast response liquid crystal devices

    NASA Astrophysics Data System (ADS)

    Wu, Yung-Hsun

    Liquid crystal (LC) has been widely used for displays, spatial light modulators, variable optical attenuators (VOAs) and other tunable photonic devices. The response time of these devices is mainly determined by the employed liquid crystal material. The response time of a LC device depends on the visco-elastic coefficient (gamma1/K11), LC cell gap (d), and applied voltage. Hence, low visco-elastic coefficient LC materials and thinner cell gap are favorable for reducing the response time. However, low visco-elastic coefficient LCs are usually associated with a low birefringence because of shorter molecular conjugation. For display applications, such as LCD TVs, low birefringence (Deltan<0.1) LCs are commonly used. However, for optical communications at 1550 nm, low birefringence requires to a thick cell gap which, in turn, increases the response time. How to obtain fast response for the LC devices is a fundamentally important and technically challenging task. In this dissertation, we investigate several methods to improve liquid crystal response time, for examples, using dual-frequency liquid crystals, polymer stabilized liquid crystals, and sheared polymer network liquid crystals. We discover a new class of material, denoted as sheared polymer network liquid crystal (SPNLC) which exhibits a submillisecond response time. Moreover, this response time is insensitive to the LC cell gap. This is the first LC device exhibiting such an interesting property. Chapters 1 and 2 describe the motivation and background of this dissertation. From chapter 3 to chapter 6, dual-frequency liquid crystals and polymer network methods are demonstrated as examples for the variable optical attenuators. Variable optical attenuator (VOA) is a key component in optical communications. Especially, the sheared PNLC VOA shows the best result; its dynamic range reaches 43 dB while the response time is in the submillisecond range at 1550 nm wavelength, which is 50 times faster than the commercial

  7. Mutual colliding impact fast ignition

    SciTech Connect

    Winterberg, Friedwardt

    2014-09-15

    It is proposed to apply the well established colliding beam technology of high energy physics to the fast hot spot ignition of a highly compressed DT (deuterium-tritium) target igniting a larger D (deuterium) burn, by accelerating a small amount of solid deuterium, and likewise a small amount of tritium, making a head-on collision in the center of the target, projecting them through conical ducts situated at the opposite side of the target and converging in its center. In their head-on collision, the relative collision velocity is 5/3 times larger compared to the collision velocity of a stationary target. The two pieces have for this reason to be accelerated to a smaller velocity than would otherwise be needed to reach upon impact the same temperature. Since the velocity distribution of the two head-on colliding projectiles is with its two velocity peaks non-Maxwellian, the maximum cross section velocity product turns out to be substantially larger than the maximum if averaged over a Maxwellian. The D and T projectiles would have to be accelerated with two sabots driven by powerful particle or laser beams, permitting a rather large acceleration length. With the substantially larger cross section-velocity product by virtue of the non-Maxwellian velocity distribution, a further advantage is that the head-on collision produces a large magnetic field by the thermomagnetic Nernst effect, enhancing propagating burn. With this concept, the ignition of the neutron-less hydrogen-boron (HB{sup 11}) reaction might even be possible in a heterogeneous assembly of the hydrogen and the boron to reduce the bremsstrahlung-losses, resembling the heterogeneous assembly in a graphite-natural uranium reactor, there to reduce the neutron losses.

  8. Optimization of Monte Carlo transport simulations in stochastic media

    SciTech Connect

    Liang, C.; Ji, W.

    2012-07-01

    This paper presents an accurate and efficient approach to optimize radiation transport simulations in a stochastic medium of high heterogeneity, like the Very High Temperature Gas-cooled Reactor (VHTR) configurations packed with TRISO fuel particles. Based on a fast nearest neighbor search algorithm, a modified fast Random Sequential Addition (RSA) method is first developed to speed up the generation of the stochastic media systems packed with both mono-sized and poly-sized spheres. A fast neutron tracking method is then developed to optimize the next sphere boundary search in the radiation transport procedure. In order to investigate their accuracy and efficiency, the developed sphere packing and neutron tracking methods are implemented into an in-house continuous energy Monte Carlo code to solve an eigenvalue problem in VHTR unit cells. Comparison with the MCNP benchmark calculations for the same problem indicates that the new methods show considerably higher computational efficiency. (authors)

  9. Neighborhood fast food restaurants and fast food consumption: A national study

    PubMed Central

    2011-01-01

    Background Recent studies suggest that neighborhood fast food restaurant availability is related to greater obesity, yet few studies have investigated whether neighborhood fast food restaurant availability promotes fast food consumption. Our aim was to estimate the effect of neighborhood fast food availability on frequency of fast food consumption in a national sample of young adults, a population at high risk for obesity. Methods We used national data from U.S. young adults enrolled in wave III (2001-02; ages 18-28) of the National Longitudinal Study of Adolescent Health (n = 13,150). Urbanicity-stratified multivariate negative binomial regression models were used to examine cross-sectional associations between neighborhood fast food availability and individual-level self-reported fast food consumption frequency, controlling for individual and neighborhood characteristics. Results In adjusted analysis, fast food availability was not associated with weekly frequency of fast food consumption in non-urban or low- or high-density urban areas. Conclusions Policies aiming to reduce neighborhood availability as a means to reduce fast food consumption among young adults may be unsuccessful. Consideration of fast food outlets near school or workplace locations, factors specific to more or less urban settings, and the role of individual lifestyle attitudes and preferences are needed in future research. PMID:21740571

  10. Fasts, feasts and festivals in diabetes-1: Glycemic management during Hindu fasts.

    PubMed

    Kalra, Sanjay; Bajaj, Sarita; Gupta, Yashdeep; Agarwal, Pankaj; Singh, S K; Julka, Sandeep; Chawla, Rajeev; Agrawal, Navneet

    2015-01-01

    This communication is the first of a series on South Asian fasts, festivals, and diabetes, designed to spread awareness and stimulate research on this aspect of diabetes and metabolic care. It describes the various fasts observed as part of Hindu religion and offers a classification scheme for them, labeling them as infrequent and frequent. The infrequent fasts are further sub-classified as brief and prolonged, to facilitate a scientific approach to glycemic management during these fasts. Pre-fast counseling, non-pharmacological therapy, pharmacological modification, and post-fast debriefing are discussed in detail. All available drug classes and molecules are covered in this article, which provides guidance about necessary changes in dosage and timing of administration. While in no way exhaustive, the brief review offers a basic framework which diabetes care professionals can use to counsel and manage persons in their care who wish to observe various Hindu fasts. PMID:25729681

  11. Fasts, feasts and festivals in diabetes-1: Glycemic management during Hindu fasts

    PubMed Central

    Kalra, Sanjay; Bajaj, Sarita; Gupta, Yashdeep; Agarwal, Pankaj; Singh, S. K.; Julka, Sandeep; Chawla, Rajeev; Agrawal, Navneet

    2015-01-01

    This communication is the first of a series on South Asian fasts, festivals, and diabetes, designed to spread awareness and stimulate research on this aspect of diabetes and metabolic care. It describes the various fasts observed as part of Hindu religion and offers a classification scheme for them, labeling them as infrequent and frequent. The infrequent fasts are further sub-classified as brief and prolonged, to facilitate a scientific approach to glycemic management during these fasts. Pre-fast counseling, non-pharmacological therapy, pharmacological modification, and post-fast debriefing are discussed in detail. All available drug classes and molecules are covered in this article, which provides guidance about necessary changes in dosage and timing of administration. While in no way exhaustive, the brief review offers a basic framework which diabetes care professionals can use to counsel and manage persons in their care who wish to observe various Hindu fasts. PMID:25729681

  12. Fast diffraction computation algorithms based on FFT

    NASA Astrophysics Data System (ADS)

    Logofatu, Petre Catalin; Nascov, Victor; Apostol, Dan

    2010-11-01

    The discovery of the Fast Fourier transform (FFT) algorithm by Cooley and Tukey meant for diffraction computation what the invention of computers meant for computation in general. The computation time reduction is more significant for large input data, but generally FFT reduces the computation time with several orders of magnitude. This was the beginning of an entire revolution in optical signal processing and resulted in an abundance of fast algorithms for diffraction computation in a variety of situations. The property that allowed the creation of these fast algorithms is that, as it turns out, most diffraction formulae contain at their core one or more Fourier transforms which may be rapidly calculated using the FFT. The key in discovering a new fast algorithm is to reformulate the diffraction formulae so that to identify and isolate the Fourier transforms it contains. In this way, the fast scaled transformation, the fast Fresnel transformation and the fast Rayleigh-Sommerfeld transform were designed. Remarkable improvements were the generalization of the DFT to scaled DFT which allowed freedom to choose the dimensions of the output window for the Fraunhofer-Fourier and Fresnel diffraction, the mathematical concept of linearized convolution which thwarts the circular character of the discrete Fourier transform and allows the use of the FFT, and last but not least the linearized discrete scaled convolution, a new concept of which we claim priority.

  13. Fast magnetoacoustic wave trains in coronal holes

    NASA Astrophysics Data System (ADS)

    Pascoe, D. J.; Nakariakov, V. M.; Kupriyanova, E. G.

    2014-08-01

    Context. Rapidly propagating coronal EUV disturbances recently discovered in the solar corona are interpreted in terms of guided fast magnetoacoustic waves. Fast magnetoacoustic waves experience geometric dispersion in waveguides, which causes localised, impulsive perturbations to develop into quasi-periodic wave trains. Aims: We consider the formation of fast wave trains in a super-radially expanding coronal hole modelled by a magnetic funnel with a field-aligned density profile that is rarefied in comparison to the surrounding plasma. This kind of structure is typical of coronal holes, and it forms a fast magnetoacoustic anti-waveguide as a local maximum in the Alfvén speed. Methods: We performed 2D MHD numerical simulations for impulsively generated perturbations to the system. Both sausage and kink perturbations are considered and the role of the density contrast ratio investigated. Results: The anti-waveguide funnel geometry refracts wave energy away from the structure. However, in this geometry the quasi-periodic fast wave trains are found to appear, too, and so can be associated with the observed rapidly propagating coronal EUV disturbances. The wave trains propagate along the external edge of the coronal hole. The fast wave trains generated in coronal holes exhibit less dispersive evolution than in the case of a dense waveguide. Conclusions: We conclude that an impulsive energy release localised in a coronal plasma inhomogeneity develops into a fast wave train for both kink and sausage disturbances and for both waveguide and anti-waveguide transverse plasma profiles.

  14. Fast Physics Testbed for the FASTER Project

    SciTech Connect

    Lin, W.; Liu, Y.; Hogan, R.; Neggers, R.; Jensen, M.; Fridlind, A.; Lin, Y.; Wolf, A.

    2010-03-15

    This poster describes the Fast Physics Testbed for the new FAst-physics System Testbed and Research (FASTER) project. The overall objective is to provide a convenient and comprehensive platform for fast turn-around model evaluation against ARM observations and to facilitate development of parameterizations for cloud-related fast processes represented in global climate models. The testbed features three major components: a single column model (SCM) testbed, an NWP-Testbed, and high-resolution modeling (HRM). The web-based SCM-Testbed features multiple SCMs from major climate modeling centers and aims to maximize the potential of SCM approach to enhance and accelerate the evaluation and improvement of fast physics parameterizations through continuous evaluation of existing and evolving models against historical as well as new/improved ARM and other complementary measurements. The NWP-Testbed aims to capitalize on the large pool of operational numerical weather prediction products. Continuous evaluations of NWP forecasts against observations at ARM sites are carried out to systematically identify the biases and skills of physical parameterizations under all weather conditions. The highresolution modeling (HRM) activities aim to simulate the fast processes at high resolution to aid in the understanding of the fast processes and their parameterizations. A four-tier HRM framework is established to augment the SCM- and NWP-Testbeds towards eventual improvement of the parameterizations.

  15. Advanced Concept Exploration for Fast Ignition Science Program, Final Report

    SciTech Connect

    Stephens, Richard Burnite; McLean, Harry M.; Theobald, Wolfgang; Akli, Kramer U.; Beg, Farhat N.; Sentoku, Yasuhiko; Schumacher, Douglass W.; Wei, Mingsheng

    2013-09-04

    The Fast Ignition (FI) Concept for Inertial Confinement Fusion (ICF) has the potential to provide a significant advance in the technical attractiveness of Inertial Fusion Energy reactors. FI differs from conventional “central hot spot” (CHS) target ignition by decoupling compression from heating: using a laser (or heavy ion beam or Z pinch) drive pulse (10’s of nanoseconds) to create a dense fuel and a second, much shorter (~10 picoseconds) high intensity pulse to ignite a small volume within the dense fuel. The physics of fast ignition process was the focus of our Advanced Concept Exploration (ACE) program. Ignition depends critically on two major issues involving Relativistic High Energy Density (RHED) physics: The laser-induced creation of fast electrons and their propagation in high-density plasmas. Our program has developed new experimental platforms, diagnostic packages, computer modeling analyses, and taken advantage of the increasing energy available at laser facilities to advance understanding of the fundamental physics underlying these issues. Our program had three thrust areas: • Understand the production and characteristics of fast electrons resulting from FI relevant laser-plasma interactions and their dependence on laser prepulse and laser pulse length. • Investigate the subsequent fast electron transport in solid and through hot (FI-relevant) plasmas. • Conduct and understand integrated core-heating experiments by comparison to simulations. Over the whole period of this project (three years for this contract), we have greatly advanced our fundamental understanding of the underlying properties in all three areas: • Comprehensive studies on fast electron source characteristics have shown that they are controlled by the laser intensity distribution and the topology and plasma density gradient. Laser pre-pulse induced pre-plasma in front of a solid surface results in increased stand-off distances from the electron origin to the high density

  16. Fast Food and Neighborhood Stroke Risk

    PubMed Central

    Morgenstern, Lewis B.; Escobar, James D.; Sánchez, Brisa N.; Hughes, Rebecca; Zuniga, Belinda G.; Garcia, Nelda; Lisabeth, Lynda D.

    2009-01-01

    Objective To investigate the association between the number of fast food restaurants and ischemic stroke in neighborhoods. Methods This work was a pre-specified part of the Brain Attack in Corpus Christi (BASIC) project. Ischemic stroke cases were prospectively ascertained in Nueces County, Texas. Home addresses were geocoded and used to establish the census tract for each stroke case. Census tracts were used as proxies for neighborhoods (n=64). Using a standard definition, fast food restaurants were identified from a commercial list. Poisson regression was used to study the association between the number of fast food restaurants in the neighborhood, using a 1-mile buffer around each census tract, and the risk of stroke in the neighborhood. Models were adjusted for demographics and neighborhood socioeconomic status (SES). Results There were 1,247 completed ischemic strokes from January 2000 through June 2003 and 262 fast food restaurants. The median number of fast food restaurants per census tract including buffer was 22 (IQR 12–33). Adjusting for neighborhood demographics and SES, the association of fast food restaurants with stroke was significant (p=0.02). The association suggested that the risk of stroke in a neighborhood increased by 1% for every fast food restaurant (RR 1.01 95% CI: 1.00–1.01). The relative risk of stroke comparing neighborhoods in the 75th to the 25th percentile of the distribution of fast food restaurants was 1.13 (95% CI: 1.02–1.25). Interpretation Controlling for demographic and SES factors, there was a significant association between fast food restaurants and stroke risk in neighborhoods in this community-based study. PMID:19743456

  17. Neoclassical electron transport in tokamaks with neutral-beam injection

    SciTech Connect

    Helander, P.; Akers, R.J.

    2005-04-15

    The collisional interaction between neutral-beam ions and bulk plasma electrons leads to convective transport of particles and energy similar to the well-known Ware pinch. These transport fluxes are calculated, and it is found that the particle flux is outward when the neutral beams are in the same direction as the plasma current and inward otherwise, while the opposite holds for the electron heat transport. This effectively shifts the neutral-beam fueling profile approximately one fast-ion banana width outward during coinjection and inward during counterinjection, and could help to explain why very different plasma behavior is sometimes observed when the direction of the plasma current is reversed.

  18. The fast debris evolution model

    NASA Astrophysics Data System (ADS)

    Lewis, H. G.; Swinerd, G. G.; Newland, R. J.; Saunders, A.

    2009-09-01

    The 'particles-in-a-box' (PIB) model introduced by Talent [Talent, D.L. Analytic model for orbital debris environmental management. J. Spacecraft Rocket, 29 (4), 508-513, 1992.] removed the need for computer-intensive Monte Carlo simulation to predict the gross characteristics of an evolving debris environment. The PIB model was described using a differential equation that allows the stability of the low Earth orbit (LEO) environment to be tested by a straightforward analysis of the equation's coefficients. As part of an ongoing research effort to investigate more efficient approaches to evolutionary modelling and to develop a suite of educational tools, a new PIB model has been developed. The model, entitled Fast Debris Evolution (FADE), employs a first-order differential equation to describe the rate at which new objects ⩾10 cm are added and removed from the environment. Whilst Talent [Talent, D.L. Analytic model for orbital debris environmental management. J. Spacecraft Rocket, 29 (4), 508-513, 1992.] based the collision theory for the PIB approach on collisions between gas particles and adopted specific values for the parameters of the model from a number of references, the form and coefficients of the FADE model equations can be inferred from the outputs of future projections produced by high-fidelity models, such as the DAMAGE model. The FADE model has been implemented as a client-side, web-based service using JavaScript embedded within a HTML document. Due to the simple nature of the algorithm, FADE can deliver the results of future projections immediately in a graphical format, with complete user-control over key simulation parameters. Historical and future projections for the ⩾10 cm LEO debris environment under a variety of different scenarios are possible, including business as usual, no future launches, post-mission disposal and remediation. A selection of results is presented with comparisons with predictions made using the DAMAGE environment model

  19. Transportation Technology: Rail Transport and Logistics

    ERIC Educational Resources Information Center

    Lang, Aaron B.

    2011-01-01

    Transportation can simply be defined as the movement of goods, services, and people from one location to another. Without an efficient means to transport goods from place to place, the economy would be nothing like it is today. Throughout the history of the United States, American railroads have paved the way toward creating a nation of great…

  20. Optimization of Supersonic Transport Trajectories

    NASA Technical Reports Server (NTRS)

    Ardema, Mark D.; Windhorst, Robert; Phillips, James

    1998-01-01

    This paper develops a near-optimal guidance law for generating minimum fuel, time, or cost fixed-range trajectories for supersonic transport aircraft. The approach uses a choice of new state variables along with singular perturbation techniques to time-scale decouple the dynamic equations into multiple equations of single order (second order for the fast dynamics). Application of the maximum principle to each of the decoupled equations, as opposed to application to the original coupled equations, avoids the two point boundary value problem and transforms the problem from one of a functional optimization to one of multiple function optimizations. It is shown that such an approach produces well known aircraft performance results such as minimizing the Brequet factor for minimum fuel consumption and the energy climb path. Furthermore, the new state variables produce a consistent calculation of flight path angle along the trajectory, eliminating one of the deficiencies in the traditional energy state approximation. In addition, jumps in the energy climb path are smoothed out by integration of the original dynamic equations at constant load factor. Numerical results performed for a supersonic transport design show that a pushover dive followed by a pullout at nominal load factors are sufficient maneuvers to smooth the jump.

  1. Secure Transportation Management

    SciTech Connect

    Gibbs, P. W.

    2014-10-15

    Secure Transport Management Course (STMC) course provides managers with information related to procedures and equipment used to successfully transport special nuclear material. This workshop outlines these procedures and reinforces the information presented with the aid of numerous practical examples. The course focuses on understanding the regulatory framework for secure transportation of special nuclear materials, identifying the insider and outsider threat(s) to secure transportation, organization of a secure transportation unit, management and supervision of secure transportation units, equipment and facilities required, training and qualification needed.

  2. Developments of fast emittance monitors for ion sources at RCNP.

    PubMed

    Yorita, T; Hatanaka, K; Fukuda, M; Shimada, K; Yasuda, Y; Saito, T; Tamura, H; Kamakura, K

    2016-02-01

    Recently, several developments of low energy beam transport line and its beam diagnostic systems have been performed to improve the injection efficiency of ion beam to azimuthally varying field cyclotron at Research Center for Nuclear Physics, Osaka University. One of those is the fast emittance monitor which can measure within several seconds for the efficient beam development and a Pepper-Pot Emittance Monitor (PPEM) has been developed. The PPEM consists of pepper-pot mask, multichannel plate, fluorescent screen, mirror, and CCD camera. The CCD image is taken via IEEE1394b to a personal computer and analyzed immediately and frequently, and then real time measurement with about 2 Hz has been achieved.

  3. Fast terahertz imaging using a quantum cascade amplifier

    SciTech Connect

    Ren, Yuan Wallis, Robert; Jessop, David Stephen; Degl'Innocenti, Riccardo; Klimont, Adam; Beere, Harvey E.; Ritchie, David A.

    2015-07-06

    A terahertz (THz) imaging scheme based on the effect of self-mixing in a 2.9 THz quantum cascade (QC) amplifier has been demonstrated. By coupling an antireflective-coated silicon lens to the facet of a QC laser, with no external optical feedback, the laser mirror losses are enhanced to fully suppress lasing action, creating a THz QC amplifier. The addition of reflection from an external target to the amplifier creates enough optical feedback to initiate lasing action and the resulting emission enhances photon-assisted transport, which in turn reduces the voltage across the device. At the peak gain point, the maximum photon density coupled back leads to a prominent self-mixing effect in the QC amplifier, leading to a high sensitivity, with a signal to noise ratio up to 55 dB, along with a fast data acquisition speed of 20 000 points per second.

  4. Catalytic Fast Pyrolysis for the Production of the Hydrocarbon Biofuels

    SciTech Connect

    Nimlos, M. R.; Robichaud, D. J.; Mukaratate, C.; Donohoe, B. S.; Iisa, K.

    2013-01-01

    Catalytic fast pyrolysis is a promising technique for conversion of biomass into hydrocarbons for use as transportation fuels. For over 30 years this process has been studied and it has been demonstrated that oils can be produced with high concentrations of hydrocarbons and low levels of oxygen. However, the yields from this type of conversion are typically low and the catalysts, which are often zeolites, are quickly deactivated through coking. In addition, the hydrocarbons produced are primarily aromatic molecules (benzene, toluene, xylene) that not desirable for petroleum refineries and are not well suited for diesel or jet engines. The goals of our research are to develop new multifunction catalysts for the production of gasoline, diesel and jet fuel range molecules and to improve process conditions for higher yields and low coking rates. We are investigating filtration and the use of hydrogen donor molecules to improve catalyst performance.

  5. Developments of fast emittance monitors for ion sources at RCNP

    NASA Astrophysics Data System (ADS)

    Yorita, T.; Hatanaka, K.; Fukuda, M.; Shimada, K.; Yasuda, Y.; Saito, T.; Tamura, H.; Kamakura, K.

    2016-02-01

    Recently, several developments of low energy beam transport line and its beam diagnostic systems have been performed to improve the injection efficiency of ion beam to azimuthally varying field cyclotron at Research Center for Nuclear Physics, Osaka University. One of those is the fast emittance monitor which can measure within several seconds for the efficient beam development and a Pepper-Pot Emittance Monitor (PPEM) has been developed. The PPEM consists of pepper-pot mask, multichannel plate, fluorescent screen, mirror, and CCD camera. The CCD image is taken via IEEE1394b to a personal computer and analyzed immediately and frequently, and then real time measurement with about 2 Hz has been achieved.

  6. Design Considerations for Economically Competitive Sodium Cooled Fast Reactors

    SciTech Connect

    Hongbin Zhang; Haihua Zhao

    2009-05-01

    The technological viability of sodium cooled fast reactors (SFR) has been established by various experimental and prototype (demonstration) reactors such as EBR-II, FFTF, Phénix, JOYO, BN-600 etc. However, the economic competitiveness of SFR has not been proven yet. The perceived high cost premium of SFRs over LWRs has been the primary impediment to the commercial expansion of SFR technologies. In this paper, cost reduction options are discussed for advanced SFR designs. These include a hybrid loop-pool design to optimize the primary system, multiple reheat and intercooling helium Brayton cycle for the power conversion system and the potential for suppression of intermediate heat transport system. The design options for the fully passive decay heat removal systems are also thoroughly examined. These include direct reactor auxiliary cooling system (DRACS), reactor vessel auxiliary cooling system (RVACS) and the newly proposed pool reactor auxiliary cooling system (PRACS) in the context of the hybrid loop-pool design.

  7. Control of wire heating with resistively guided fast electrons through an inverse conical taper

    SciTech Connect

    Robinson, A. P. L. Schmitz, H.; Green, J. S.; Booth, N.; Ridgers, C. P.; Pasley, J.

    2015-04-15

    The heating of a solid wire embedded in a solid substrate (of lower Z material) with relativistic electrons generated by ultra-intense laser irradiation is considered. Previously, it has been noted that the initial angular distribution of the fast electrons is a highly important factor in the efficacy of the heating [Robinson et al., Phys. Plasmas 20, 122701 (2013)]. We show that, using 3D numerical simulations, the addition of an inverse conical taper at the front of wire can considerably improve the heating of the wire due to the reduction of angular spread of the fast electrons which is caused by transport through the inverse conical taper [Robinson et al., “Guiding of laser-generated fast electrons by exploiting the resistivity-gradients around a conical guide element,” Plasma Phys. Controlled Fusion (to be published)].

  8. Evaluation of Fast-Time Wake Vortex Models using Wake Encounter Flight Test Data

    NASA Technical Reports Server (NTRS)

    Ahmad, Nashat N.; VanValkenburg, Randal L.; Bowles, Roland L.; Limon Duparcmeur, Fanny M.; Gloudesman, Thijs; van Lochem, Sander; Ras, Eelco

    2014-01-01

    This paper describes a methodology for the integration and evaluation of fast-time wake models with flight data. The National Aeronautics and Space Administration conducted detailed flight tests in 1995 and 1997 under the Aircraft Vortex Spacing System Program to characterize wake vortex decay and wake encounter dynamics. In this study, data collected during Flight 705 were used to evaluate NASA's fast-time wake transport and decay models. Deterministic and Monte-Carlo simulations were conducted to define wake hazard bounds behind the wake generator. The methodology described in this paper can be used for further validation of fast-time wake models using en-route flight data, and for determining wake turbulence constraints in the design of air traffic management concepts.

  9. A tangentially viewing fast ion D-alpha diagnostic for NSTX.

    PubMed

    Bortolon, A; Heidbrink, W W; Podestà, M

    2010-10-01

    A second fast ion D-alpha (FIDA) installation is planned at NSTX to complement the present perpendicular viewing FIDA diagnostics. Following the present diagnostic scheme, the new diagnostic will consist of two instruments: a spectroscopic diagnostic that measures fast ion spectra and profiles at 16 radial points with 5-10 ms resolution and a system that uses a band pass filter and photomultiplier to measure changes in FIDA light with 50 kHz sampling rate. The new pair of FIDA instruments will view the heating beams tangentially. The viewing geometry minimizes spectral contamination by beam emission or edge sources of background emission. The improved velocity-space resolution will provide detailed information about neutral-beam current drive and about fast ion acceleration and transport by injected radio frequency waves and plasma instabilities.

  10. A tangentially viewing fast ion D-alpha diagnostic for NSTX

    SciTech Connect

    Bortolon, A.; Heidbrink, W. W.; Podesta, M.

    2010-10-15

    A second fast ion D-alpha (FIDA) installation is planned at NSTX to complement the present perpendicular viewing FIDA diagnostics. Following the present diagnostic scheme, the new diagnostic will consist of two instruments: a spectroscopic diagnostic that measures fast ion spectra and profiles at 16 radial points with 5-10 ms resolution and a system that uses a band pass filter and photomultiplier to measure changes in FIDA light with 50 kHz sampling rate. The new pair of FIDA instruments will view the heating beams tangentially. The viewing geometry minimizes spectral contamination by beam emission or edge sources of background emission. The improved velocity-space resolution will provide detailed information about neutral-beam current drive and about fast ion acceleration and transport by injected radio frequency waves and plasma instabilities.

  11. The effect of the fast-ion profile on Alfvén eigenmode stability

    NASA Astrophysics Data System (ADS)

    Heidbrink, W. W.; Van Zeeland, M. A.; Austin, M. E.; Bass, E. M.; Ghantous, K.; Gorelenkov, N. N.; Grierson, B. A.; Spong, D. A.; Tobias, B. J.

    2013-09-01

    Different combinations of on-axis and off-axis neutral beams are injected into DIII-D plasmas that are unstable to reversed shear Alfvén eigenmodes (RSAE) and toroidal Alfvén eigenmodes (TAE). The variations alter the classically expected fast-ion gradient ∇βf in the plasma interior. Off-axis injection reduces the amplitude of RSAE activity an order of magnitude. Core TAEs are also strongly stabilized. In contrast, at larger minor radius, the fast-ion gradient is similar for on- and off-axis injection and switching the angle of injection has a weaker effect on the stability of TAEs. The average mode amplitude correlates strongly with the classically expected profile but the measured profile relaxes to similar values independent of the fraction of off-axis beams. The observations agree qualitatively with a ‘critical-gradient’ model of fast-ion transport.

  12. Guiding and collimating fast electron beam by the quasi-static electromagnetic field array

    SciTech Connect

    Wang, J.; Zhao, Z. Q.; He, W. H.; Dong, K. G.; Wu, Y. C.; Zhu, B.; Zhang, T. K.; Zhang, B.; Zhang, Z. M.; Gu, Y. Q.; Cao, L. H.

    2014-10-15

    A guidance and collimation scheme for fast electron beam in a traverse periodic quasi-static electromagnetic field array is proposed with the semi-analytic method and the particle-in-cell simulation. The sheath electric fields on the surfaces of nanowires and the magnetic fields around the nanowires form a traverse periodic quasi-static electromagnetic field array. Therefore, most of the fast electrons are confined at the nanowire surfaces and transport forward. More importantly, due to the divergent property of the beams, the magnitudes of the generated fields decrease with the target depth. The lateral momenta of the electrons convert into the forward momenta through Lorenz force, and they cannot recover their initial values. Therefore, the fast electrons can be guided and collimated efficiently in the gaps between the nanowires. In our particle-in-cell simulations, the observed guiding efficiency exceeds 80% compared with the reference target.

  13. Role of lattice structure and low temperature resistivity in fast-electron-beam filamentation in carbon

    NASA Astrophysics Data System (ADS)

    Dance, R. J.; Butler, N. M. H.; Gray, R. J.; MacLellan, D. A.; Rusby, D. R.; Scott, G. G.; Zielbauer, B.; Bagnoud, V.; Xu, H.; Robinson, A. P. L.; Desjarlais, M. P.; Neely, D.; McKenna, P.

    2016-01-01

    The influence of low temperature (eV to tens-of-eV) electrical resistivity on the onset of the filamentation instability in fast-electron transport is investigated in targets comprising of layers of ordered (diamond) and disordered (vitreous) carbon. It is shown experimentally and numerically that the thickness of the disordered carbon layer influences the degree of filamentation of the fast-electron beam. Strong filamentation is produced if the thickness is of the order of 60 μm or greater, for an electron distribution driven by a sub-picosecond, mid-1020 Wcm-2 laser pulse. It is shown that the position of the vitreous carbon layer relative to the fast-electron source (where the beam current density and background temperature are highest) does not have a strong effect because the resistive filamentation growth rate is high in disordered carbon over a wide range of temperatures up to the Spitzer regime.

  14. Fast Action Can Prevent Sepsis Death: CDC

    MedlinePlus

    ... fullstory_160574.html Fast Action Can Prevent Sepsis Death: CDC Know the signs of extreme response to ... treated long before it causes severe illness or death, U.S. health officials report. Sepsis, or septicemia, occurs ...

  15. Fast internal dynamics in alcohol dehydrogenase.

    PubMed

    Monkenbusch, M; Stadler, A; Biehl, R; Ollivier, J; Zamponi, M; Richter, D

    2015-08-21

    Large-scale domain motions in alcohol dehydrogenase (ADH) have been observed previously by neutron spin-echo spectroscopy (NSE). We have extended the investigation on the dynamics of ADH in solution by using high-resolution neutron time-of-flight (TOF) and neutron backscattering (BS) spectroscopy in the incoherent scattering range. The observed hydrogen dynamics were interpreted in terms of three mobility classes, which allowed a simultaneous description of the measured TOF and BS spectra. In addition to the slow global protein diffusion and domain motions observed by NSE, a fast internal process could be identified. Around one third of the protons in ADH participate in the fast localized diffusive motion. The diffusion coefficient of the fast internal motions is around two third of the value of the surrounding D2O solvent. It is tempting to associate the fast internal process with solvent exposed amino acid residues with dangling side chains. PMID:26298156

  16. Fast and practical parallel polynomial interpolation

    SciTech Connect

    Egecioglu, O.; Gallopoulos, E.; Koc, C.K.

    1987-01-01

    We present fast and practical parallel algorithms for the computation and evaluation of interpolating polynomials. The algorithms make use of fast parallel prefix techniques for the calculation of divided differences in the Newton representation of the interpolating polynomial. For n + 1 given input pairs the proposed interpolation algorithm requires 2 (log (n + 1)) + 2 parallel arithmetic steps and circuit size O(n/sup 2/). The algorithms are numerically stable and their floating-point implementation results in error accumulation similar to that of the widely used serial algorithms. This is in contrast to other fast serial and parallel interpolation algorithms which are subject to much larger roundoff. We demonstrate that in a distributed memory environment context, a cube connected system is very suitable for the algorithms' implementation, exhibiting very small communication cost. As further advantages we note that our techniques do not require equidistant points, preconditioning, or use of the Fast Fourier Transform. 21 refs., 4 figs.

  17. Cosmology: Home of a fast radio burst

    NASA Astrophysics Data System (ADS)

    Lorimer, Duncan

    2016-02-01

    Our understanding of fast radio bursts -- intense pulses of radio waves -- and their use as cosmic probes promises to be transformed now that one burst has been associated with a galaxy of known distance from Earth. See Letter p.453

  18. Fast internal dynamics in alcohol dehydrogenase

    SciTech Connect

    Monkenbusch, M.; Stadler, A. Biehl, R.; Richter, D.; Ollivier, J.; Zamponi, M.

    2015-08-21

    Large-scale domain motions in alcohol dehydrogenase (ADH) have been observed previously by neutron spin-echo spectroscopy (NSE). We have extended the investigation on the dynamics of ADH in solution by using high-resolution neutron time-of-flight (TOF) and neutron backscattering (BS) spectroscopy in the incoherent scattering range. The observed hydrogen dynamics were interpreted in terms of three mobility classes, which allowed a simultaneous description of the measured TOF and BS spectra. In addition to the slow global protein diffusion and domain motions observed by NSE, a fast internal process could be identified. Around one third of the protons in ADH participate in the fast localized diffusive motion. The diffusion coefficient of the fast internal motions is around two third of the value of the surrounding D{sub 2}O solvent. It is tempting to associate the fast internal process with solvent exposed amino acid residues with dangling side chains.

  19. FastBit: Interactively Searching Massive Data

    SciTech Connect

    Wu, Kesheng; Ahern, Sean; Bethel, E. Wes; Chen, Jacqueline; Childs, Hank; Cormier-Michel, Estelle; Geddes, Cameron; Gu, Junmin; Hagen, Hans; Hamann, Bernd; Koegler, Wendy; Lauret, Jerome; Meredith, Jeremy; Messmer, Peter; Otoo, Ekow; Perevoztchikov, Victor; Poskanzer, Arthur; Prabhat,; Rubel, Oliver; Shoshani, Arie; Sim, Alexander; Stockinger, Kurt; Weber, Gunther; Zhang, Wei-Ming

    2009-06-23

    As scientific instruments and computer simulations produce more and more data, the task of locating the essential information to gain insight becomes increasingly difficult. FastBit is an efficient software tool to address this challenge. In this article, we present a summary of the key underlying technologies, namely bitmap compression, encoding, and binning. Together these techniques enable FastBit to answer structured (SQL) queries orders of magnitude faster than popular database systems. To illustrate how FastBit is used in applications, we present three examples involving a high-energy physics experiment, a combustion simulation, and an accelerator simulation. In each case, FastBit significantly reduces the response time and enables interactive exploration on terabytes of data.

  20. Investigating the possibility of a monitoring fast ion diagnostic for ITER.

    PubMed

    De Angelis, R; von Hellermann, M G; Orsitto, F P; Tugarinov, S

    2008-10-01

    In burning plasma fusion devices, fast ion transport plays a central role in the performances of the machines. Moreover the losses of energetic particles might cause severe damages on plasma facing components. Therefore real time measurements of fast ion transport would provide valuable information for safe and reliable plasma operations. In this paper, we examine the feasibility of a monitoring system based on active charge exchange recombination spectroscopy making use of the 0.5 MeV/amu ITER heating neutral beams for detecting fast (4)He(+2) (alphas) particles in ITER plasmas. There are two time scales relevant to fast ion dynamics: the first is the slowing down time of the distribution function which is of the order of 1 s, and the second is the time scale of burstlike transport events such as collective Alfven mode excitations, which--for typical ITER plasma parameters--can be as low as 0.2-1 ms. To detect such fast events a broadband high-throughput spectrometer is needed, while for the reconstruction of the alpha velocity distribution function a higher resolution spectrometer and longer integration time are necessary. To monitor a spatial redistribution of fast particles due to the propagation of the instability, it is proposed to use a limited number of spatial channels, looking at the charge exchange He II spectra induced by the heating beams, whose energy matches the slowing down energies of fast particles. The proposal is to share the motional stark effect periscope on equatorial port 3 [A. Malaquias et al., Rev. Sci. Instrum. 75, 3393 (2004)] adding additional fibers and suitable instruments. A signal to noise ratio of 5 could be achieved with a spatial resolution of a/15 and a time resolution of 5 ms, in a broad spectral band of 100 A, corresponding to the spectral broadening of the line emitted by alpha particles with energies DeltaE < or = 1.5 MeV. Fast H and D ion populations created by heating neutral beam or ion cyclotron resonance heating are

  1. Effects of nonlocal heat transport on laser implosion

    SciTech Connect

    Mima, K.; Honda, M.; Miyamoto, S.; Kato, S.

    1996-05-01

    A numerical simulation code describing the spherically symmetric implosion hydrodynamics has been developed to investigate the nonlocal heat transport effects on stable high velocity implosion and fast ignition. In the implosion simulation code HIMICO, the Fokker Planck equation for electron transport is solved to describe the nonlocal effects. For high ablation pressure implosion with a pressure higher than 200 Mbar, the isentrope is found higher by a factor 2 in the nonlocal transport model than in the Spitzer Harm model. As for the fast ignition simulation, the neutron yield for the high density compression with 10 KJ laser increases to be 20 times by injecting an additional heating pulse of 10 KJ with 1 psec. {copyright} {ital 1996 American Institute of Physics.}

  2. Digital fast neutron radiography of steel reinforcing bar in concrete

    NASA Astrophysics Data System (ADS)

    Mitton, K.; Jones, A.; Joyce, M. J.

    2014-12-01

    Neutron imaging has previously been used in order to test for cracks, degradation and water content in concrete. However, these techniques often fall short of alternative non-destructive testing methods, such as γ-ray and X-ray imaging, particularly in terms of resolution. Further, thermal neutron techniques can be compromised by the significant expense associated with thermal neutron sources of sufficient intensity to yield satisfactory results that can often precipitate the need for a reactor. Such embodiments are clearly not portable in the context of the needs of field applications. This paper summarises the results of a study to investigate the potential for transmission radiography based on fast neutrons. The objective of this study was to determine whether the presence of heterogeneities in concrete, such as reinforcement structures, could be identified on the basis of variation in transmitted fast-neutron flux. Monte-Carlo simulations have been performed and the results from these are compared to those arising from practical tests using a 252Cf source. The experimental data have been acquired using a digital pulse-shape discrimination system that enables fast neutron transmission to be studied across an array of liquid scintillators placed in close proximity to samples under test, and read out in real time. Whilst this study does not yield sufficient spatial resolution, a comparison of overall flux ratios does provide a basis for the discrimination between samples with contrasting rebar content. This approach offers the potential for non-destructive testing that gives less dose, better transportability and better accessibility than competing approaches. It is also suitable for thick samples where γ-ray and X-ray methods can be limited.

  3. Sociodemographic differences in fast food price sensitivity

    PubMed Central

    Meyer, Katie A.; Guilkey, David K.; Ng, Shu Wen; Duffey, Kiyah J.; Popkin, Barry M.; Kiefe, Catarina I.; Steffen, Lyn M.; Shikany, James M.; Gordon-Larsen, Penny

    2014-01-01

    Importance Fiscal food policies (e.g., taxation) are increasingly proposed to improve population-level health, but their impact on health disparities is unknown. Objective We estimated subgroup-specific effects of fast food price changes on fast food consumption and cardio-metabolic outcomes, hypothesizing inverse associations between fast food price with fast food consumption, BMI, and insulin resistance and stronger associations among blacks (vs. whites) and participants with relatively lower education or income. Design 20-year follow-up (5 exams) in a biracial U.S. prospective cohort: Coronary Artery Risk Development in Young Adults (CARDIA) (1985/86–2005/06, baseline n=5,115). Participants Aged 18–30 at baseline; designed for equal recruitment by race (black/white), educational attainment, age, and gender. Exposures Community-level price data from the Council for Community and Economic Research (C2ER) temporally- and geographically-linked to study participants’ home address at each exam. Main outcome and measures Participant-reported number of fast food eating occasions per week; BMI (kg/m2) from clinical assessment of weight and height; homeostatic model assessment insulin resistance (HOMA-IR) from fasting glucose and insulin. Covariates included individual- and community-level social and demographic factors. Results In repeated measures regression, multivariable-adjusted associations between fast food price and consumption were non-linear (quadratic, p<0.001), with significant inverse estimated effects on consumption at higher prices; estimates varied according to race (interaction term p=0.04), income (p=0.07), and education (p=0.03). For example, at the 10th percentile of price ($1.25/serving), blacks and whites had mean fast food consumption (times/week) of 2.2 (95% CI: 2.1–2.3) and 1.6 (1.5–1.7), respectively, while at the 90th percentile of price ($1.53/serving), respective mean consumption estimates were 1.9 (1.8–2.0) and 1.5 (1.4–1.6). We

  4. Fast ignition of inertial confinement fusion targets

    SciTech Connect

    Gus'kov, S. Yu.

    2013-01-15

    Results of studies on fast ignition of inertial confinement fusion (ICF) targets are reviewed. The aspects of the fast ignition concept, which consists in the separation of the processes of target ignition and compression due to the synchronized action of different energy drivers, are considered. Criteria for the compression ratio and heating rate of a fast ignition target, the energy balance, and the thermonuclear gain are discussed. The results of experimental and theoretical studies of the heating of a compressed target by various types of igniting drivers, namely, beams of fast electrons and light ions produced under the action of a petawatt laser pulse on the target, a heavy-ion beam generated in the accelerator, an X-ray pulse, and a hydrodynamic flow of laser-accelerated matter, are analyzed. Requirements to the igniting-driver parameters that depend on the fast ignition criteria under the conditions of specific target heating mechanisms, as well as possibilities of practical implementation of these requirements, are discussed. The experimental programs of various laboratories and the prospects of practical implementation of fast ignition of ICF targets are reviewed. To date, fast ignition is the most promising method for decreasing the ignition energy and increasing the thermonuclear gain of an ICF plasma. A large number of publications have been devoted to investigations of this method and adjacent problems of the physics of igniting drivers and their interaction with plasma. This review presents results of only some of these studies that, in the author's opinion, allow one to discuss in detail the main physical aspects of the fast ignition concept and understand the current state and prospects of studies in this direction.

  5. COUPLED FAST-THERMAL POWER BREEDER REACTOR

    DOEpatents

    Avery, R.

    1961-07-18

    A nuclear reactor having a region operating predominantly on fast neutrons and another region operating predominantly on slow neutrons is described. The fast region is a plutonium core and the slow region is a natural uranium blanket around the core. Both of these regions are free of moderator. A moderating reflector surrounds the uranium blanket. The moderating material and thickness of the reflector are selected so that fissions in the uranium blanket make a substantial contribution to the reactivity of the reactor.

  6. Fast X-Ray Fluorescence Microtomography of Hydrated Biological Samples

    PubMed Central

    Lombi, Enzo; de Jonge, Martin D.; Donner, Erica; Kopittke, Peter M.; Howard, Daryl L.; Kirkham, Robin; Ryan, Chris G.; Paterson, David

    2011-01-01

    Metals and metalloids play a key role in plant and other biological systems as some of them are essential to living organisms and all can be toxic at high concentrations. It is therefore important to understand how they are accumulated, complexed and transported within plants. In situ imaging of metal distribution at physiological relevant concentrations in highly hydrated biological systems is technically challenging. In the case of roots, this is mainly due to the possibility of artifacts arising during sample preparation such as cross sectioning. Synchrotron x-ray fluorescence microtomography has been used to obtain virtual cross sections of elemental distributions. However, traditionally this technique requires long data acquisition times. This has prohibited its application to highly hydrated biological samples which suffer both radiation damage and dehydration during extended analysis. However, recent advances in fast detectors coupled with powerful data acquisition approaches and suitable sample preparation methods can circumvent this problem. We demonstrate the heightened potential of this technique by imaging the distribution of nickel and zinc in hydrated plant roots. Although 3D tomography was still impeded by radiation damage, we successfully collected 2D tomograms of hydrated plant roots exposed to environmentally relevant metal concentrations for short periods of time. To our knowledge, this is the first published example of the possibilities offered by a new generation of fast fluorescence detectors to investigate metal and metalloid distribution in radiation-sensitive, biological samples. PMID:21674049

  7. Studies of electron and proton isochoric heating for fast ignition

    SciTech Connect

    Mackinnon, A; Key, M; Akli, K; Beg, F; Clarke, R; Clarke, D; Chen, M; Chung, H; Chen, S; Freeman, R; Green, J; Gu, P; Gregori, G; Highbarger, K; Habara, H; Hatchett, S; Hey, D; Heathcote, R; Hill, J; King, J; Kodama, R; Koch, J; Lancaster, K; Langdon, B; Murphy, C; Norreys, P; Neely, D; Nakatsutsumi, M; Nakamura, H; Patel, N; Patel, P; Pasley, J; Snavley, R; Stephens, R; Stoeckl, C; Foord, M; Tabak, M; Theobald, W; Storm, M; Tanaka, K; Tempo, M; Toley, M; Town, R; Wilks, S; VanWoerkom, L; Weber, R; Yabuuchi, T; Zhang, B

    2006-10-02

    Isochoric heating of inertially confined fusion plasmas by laser driven MeV electrons or protons is an area of great topical interest in the inertial confinement fusion community, particularly with respect to the fast ignition (FI) proposal to use this technique to initiate burn in a fusion capsule. Experiments designed to investigate electron isochoric heating have measured heating in two limiting cases of interest to fast ignition, small planar foils and hollow cones. Data from Cu K{alpha} fluorescence, crystal x-ray spectroscopy of Cu K shell emission, and XUV imaging at 68eV and 256 eV are used to test PIC and Hybrid PIC modeling of the interaction. Isochoric heating by focused proton beams generated at the concave inside surface of a hemi-shell and from a sub hemi-shell inside a cone have been studied with the same diagnostic methods plus imaging of proton induced K{alpha}. Conversion efficiency to protons has also been measured and modeled. Conclusions from the proton and electron heating experiments will be presented. Recent advances in modeling electron transport and innovative target designs for reducing igniter energy and increasing gain curves will also be discussed.

  8. Fast x-ray fluorescence microtomography of hydrated biological samples.

    PubMed

    Lombi, Enzo; de Jonge, Martin D; Donner, Erica; Kopittke, Peter M; Howard, Daryl L; Kirkham, Robin; Ryan, Chris G; Paterson, David

    2011-01-01

    Metals and metalloids play a key role in plant and other biological systems as some of them are essential to living organisms and all can be toxic at high concentrations. It is therefore important to understand how they are accumulated, complexed and transported within plants. In situ imaging of metal distribution at physiological relevant concentrations in highly hydrated biological systems is technically challenging. In the case of roots, this is mainly due to the possibility of artifacts arising during sample preparation such as cross sectioning. Synchrotron x-ray fluorescence microtomography has been used to obtain virtual cross sections of elemental distributions. However, traditionally this technique requires long data acquisition times. This has prohibited its application to highly hydrated biological samples which suffer both radiation damage and dehydration during extended analysis. However, recent advances in fast detectors coupled with powerful data acquisition approaches and suitable sample preparation methods can circumvent this problem. We demonstrate the heightened potential of this technique by imaging the distribution of nickel and zinc in hydrated plant roots. Although 3D tomography was still impeded by radiation damage, we successfully collected 2D tomograms of hydrated plant roots exposed to environmentally relevant metal concentrations for short periods of time. To our knowledge, this is the first published example of the possibilities offered by a new generation of fast fluorescence detectors to investigate metal and metalloid distribution in radiation-sensitive, biological samples. PMID:21674049

  9. IBW and Fast Wave Launching and Damping on TFTR

    SciTech Connect

    First Author = J.C. Hosea

    1997-01-01

    Antennas to provide direct IBW (ion-Bernstein wave) excitation and to improve the launched spectrum and power handling for mode-coverted (MC) IBW excitation have been installed on TFTR (Tokamak Fusion Test Reactor) to support studies of transport barrier formation inside the TFTR plasma. Initial IBW launching/heating experiments have been performed at f(subscript) rf (nonsubsript) = 76 MHz and 50.6 MHz for several antenna and plasma positions, several mangetic fields [D, T, H, (superscript) 3 (nonsuperscript) He resonances], and with and without neutral-beam injection. Although the measured surface density profiles in front of the antenna should theoretically support IBW launching to the plasma core via EPW (electron plasma wave) excitation, loading resistance parameter dependence and heating results suggest that the wave energy is being deposited mostly in the plasma periphery. The potential roles of surface fast-wave and near-field excitation/damping on the IBW performance are discussed. Also MC IBW damping of the fast wave has been significantly improved through the removal of lithium 7 from the plasma.

  10. Isochoric heating from fast electrons using mass limited targets

    NASA Astrophysics Data System (ADS)

    Koenig, Michel; Baton, Sophie; Guillou, Perceval; Audebert, Patrick; Lecherbourg, Ludovic; Barbrel, Benjamin; Bastiani-Ceccotti, Serna; Rousseaux, Christophe; Gremillet, Laurent; Lefevre, Erik; Back, Christina; Patel, Pravesh; Cowan, Tom; Rassuchine, Jenny

    2008-04-01

    Experiments to investigate fast electron transport in thin, mass-limited multilayer targets were performed at the LULI 100 TW laser facility. The targets were composed of V/Cu/Al and varied from 300 to 50 μm in diameter. They were isochorically heated by a 20 J, 300 ps laser pulse that delivered I˜2x10^19 W/cm2 to form a warm dense plasma. X-ray emission from the Cu and Al layers was measured using conical and spherical Bragg crystals. Time-resolved Kα emission spectra were also obtained using an ultra-fast streak camera indicating a total refluxing of the electrons. The data from targets of different size and/or Cu layer thickness are compared and analyzed to better understand the heating of the target and temperature of the plasma. Temperatures up to several hundred eV have been deduced from detailed spectra analysis. Comparison with PIC simulations will be presented.

  11. Temporal Characterization of Electron Beam Bunches with a Fast Streak Camera at the JLab FEL Facility

    SciTech Connect

    S. Zhang; S.V. Benson; D. Douglas; D. Hardy; C. Hernandez-Garcia; K. Jordan; G. Neil; Michelle D. Shinn

    2005-08-21

    The design and construction of an optical transport that brings synchrotron radiation from electron bunches to a fast streak camera in a remote area has become a useful tool for online observation of bunch length and stability. This paper will report on the temporal measurements we have done, comparison with simulations, and the on-going work for another imaging optical transport system that will make possible the direct measurement of the longitudinal phase space by measuring the bunch length as a function of energy

  12. Kinetic mechanisms of inhibitor binding: relevance to the fast-acting slow-binding paradigm.

    PubMed Central

    Falk, S; Oulianova, N; Berteloot, A

    1999-01-01

    Although phlorizin inhibition of Na+-glucose cotransport occurs within a few seconds, 3H-phlorizin binding to the sodium-coupled glucose transport protein(s) requires several minutes to reach equilibrium (the fast-acting slow-binding paradigm). Using kinetic models of arbitrary dimension that can be reduced to a two-state diagram according to Cha's formalism, we show that three basic mechanisms of inhibitor binding can be identified whereby the inhibitor binding step either (A) represents, (B) precedes, or (C) follows the rate-limiting step in a binding reaction. We demonstrate that each of mechanisms A-C is associated with a set of unique kinetic properties, and that the time scale over which one may expect to observe mechanism C is conditioned by the turnover number of the catalytic cycle. In contrast, mechanisms A and B may be relevant to either fast-acting or slow-binding inhibitors. However, slow-binding inhibition according to mechanism A may not be compatible with a fast-acting behavior on the steady-state time scale of a few seconds. We conclude that the recruitment hypothesis (mechanism C) cannot account for slow phlorizin binding to the sodium-coupled glucose transport protein(s), and that mechanism B is the only alternative that may explain the fast-acting slow-binding paradigm. PMID:10388748

  13. Interaction of Fast Ions with Global Plasma Modes in the C-2 Field Reversed Configuration Experiment

    NASA Astrophysics Data System (ADS)

    Smirnov, Artem; Dettrick, Sean; Clary, Ryan; Korepanov, Sergey; Thompson, Matthew; Trask, Erik; Tuszewski, Michel

    2012-10-01

    A high-confinement operating regime [1] with plasma lifetimes significantly exceeding past empirical scaling laws was recently obtained by combining plasma gun edge biasing and tangential Neutral Beam Injection (NBI) in the C-2 field-reversed configuration (FRC) experiment [2, 3]. We present experimental and computational results on the interaction of fast ions with the n=2 rotational and n=1 wobble modes in the C-2 FRC. It is found that the n=2 mode is similar to quadrupole magnetic fields in its detrimental effect on the fast ion transport due to symmetry breaking. The plasma gun generates an inward radial electric field, thus stabilizing the n=2 rotational instability without applying the quadrupole magnetic fields. The resultant FRCs are nearly axisymmetric, which enables fast ion confinement. The NBI further suppresses the n=2 mode, improves the plasma confinement characteristics, and increases the plasma configuration lifetime [4]. The n=1 wobble mode has relatively little effect on the fast ion transport, likely due to the approximate axisymmetry about the displaced plasma column. [4pt] [1] M. Tuszewski et al., Phys. Rev. Lett. 108, 255008 (2012).[0pt] [2] M. Binderbauer et al., Phys. Rev. Lett. 105, 045003 (2010).[0pt] [3] H.Y. Guo et al., Phys. Plasmas 18, 056110 (2011).[0pt] [4] M. Tuszewski et al., Phys. Plasmas 19, 056108 (2012)

  14. Transportation Management Workshop: Proceedings

    SciTech Connect

    Not Available

    1993-10-01

    This report is a compilation of discussions presented at the Transportation Management Workshop held in Gaithersburg, Maryland. Topics include waste packaging, personnel training, robotics, transportation routing, certification, containers, and waste classification.

  15. Transportation and handling loads

    NASA Technical Reports Server (NTRS)

    Ostrem, F. E.

    1971-01-01

    Criteria and recommended practices are presented for the prediction and verification of transportation and handling loads for the space vehicle structure and for monitoring these loads during transportation and handling of the vehicle or major vehicle segments. Elements of the transportation and handling systems, and the forcing functions and associated loads are described. The forcing functions for common carriers and typical handling devices are assessed, and emphasis is given to the assessment of loads at the points where the space vehicle is supported during transportation and handling. Factors which must be considered when predicting the loads include the transportation and handling medium; type of handling fixture; transport vehicle speed; types of terrain; weather (changes in pressure of temperature, wind, etc.); and dynamics of the transportation modes or handling devices (acceleration, deceleration, and rotations of the transporter or handling device).

  16. Thermodynamics of nuclear transport

    NASA Astrophysics Data System (ADS)

    Wang, Ching-Hao; Mehta, Pankaj; Elbaum, Michael

    Molecular transport across the nuclear envelope is important for eukaryotes for gene expression and signaling. Experimental studies have revealed that nuclear transport is inherently a nonequilibrium process and actively consumes energy. In this work we present a thermodynamics theory of nuclear transport for a major class of nuclear transporters that are mediated by the small GTPase Ran. We identify the molecular elements responsible for powering nuclear transport, which we term the ``Ran battery'' and find that the efficiency of transport, measured by the cargo nuclear localization ratio, is limited by competition between cargo molecules and RanGTP to bind transport receptors, as well as the amount of NTF2 (i.e. RanGDP carrier) available to circulate the energy flow. This picture complements our current understanding of nuclear transport by providing a comprehensive thermodynamics framework to decipher the underlying biochemical machinery. Pm and CHW were supported by a Simons Investigator in the Mathematical Modeling in Living Systems grant (to PM).

  17. Mixing and Transport.

    PubMed

    Chang, Chein-Chi; Chapman, Tom; Siverts-Wong, Elena; Wei, Li; Mei, Ying

    2016-10-01

    This section covers research published during the calendar year 2015 on mixing and transport processes. The review covers mixing of anaerobic digesters, mixing of heat transfer, and environmental fate and transport. PMID:27620101

  18. Basic Transportation Economics

    NASA Technical Reports Server (NTRS)

    Kneafsey, J. T.

    1972-01-01

    Transportation economics is an integral part of all transportation activities. Refined, detailed, and careful economic analyses consider conduct-performance methodology and the specifications of production, cost and demand functions.

  19. Fast temporal correlation between hard X-ray and ultraviolet continuum brightenings

    NASA Technical Reports Server (NTRS)

    Machado, Marcos E.; Mauas, Pablo J.

    1986-01-01

    Recent Solar Maximum Mission (SMM) observations have shown fast and simultaneous increases in hard X-rays (HXR, E25 keV) and ultraviolet continuum (UVC, lambda lambda approx. equals 1600 and 1388 A) radiation. A simple and natural explanation is given for this phenomenon to happen, which does not involve extreme conditions for energy transport processes, and confirms earlier results on the effect of XUV photoionization in the solar atmosphere.

  20. Fast and Reversible Actuation of Metallic Muscles Composed of Nickel Nanowire-Forest.

    PubMed

    Cheng, Chuan; Weissmüller, Jörg; Ngan, Alfonso H W

    2016-07-01

    Surface-charge-induced reversible and millimeter-scale deflection is found in a bilayered Ni cantilever upon cyclic potential triggering. The nanowire-forest structure, in which unidirectional primary nanowires are evenly separated by cross-linking subnanowires, ensures fast ion transport leading to a record-high strain response time ≈0.1 s. The actuation is sustainable beyond 800 cycles; the strain energy is compatible with human skeletal muscles. PMID:27146431

  1. Design of unique pins for irradiation of higher actinides in a fast reactor

    SciTech Connect

    Basmajian, J.A.; Birney, K.R.; Weber, E.T.; Adair, H.L.; Quinby, T.C.; Raman, S.; Butler, J.K.; Bateman, B.C.; Swanson, K.M.

    1982-03-01

    The actinides produced by transmutation reactions in nuclear reactor fuels are a significant factor in nuclear fuel burnup, transportation and reprocessing. Irradiation testing is a primary source of data of this type. A segmented pin design was developed which provides for incorporation of multiple specimens of actinide oxides for irradiation in the UK's Prototype Fast Reactor (PFR) at Dounreay Scotland. Results from irradiation of these pins will extend the basic neutronic and material irradiation behavior data for key actinide isotopes.

  2. Subseabed disposal transportation system

    SciTech Connect

    Allen, Jr., G. C.; Vernon, M. E.; Anderson, D. R.

    1980-01-01

    Transportation requirements and interfaces are being considered in the evaluation of the seabed disposal option. Technical direction and planning are on-going to ensure the development of major transportation systems in support of the seabed disposal option. Factors which affect the risk and effectiveness of transportation are being included in site selection criteria. However, detailed development of port facilities and transport/emplacement equipment is still several years into the future. (DMC)

  3. Structural Properties of the Brazilian Air Transportation Network.

    PubMed

    Couto, Guilherme S; da Silva, Ana Paula Couto; Ruiz, Linnyer B; Benevenuto, Fabrício

    2015-09-01

    The air transportation network in a country has a great impact on the local, national and global economy. In this paper, we analyze the air transportation network in Brazil with complex network features to better understand its characteristics. In our analysis, we built networks composed either by national or by international flights. We also consider the network when both types of flights are put together. Interesting conclusions emerge from our analysis. For instance, Viracopos Airport (Campinas City) is the most central and connected airport on the national flights network. Any operational problem in this airport separates the Brazilian national network into six distinct subnetworks. Moreover, the Brazilian air transportation network exhibits small world characteristics and national connections network follows a power law distribution. Therefore, our analysis sheds light on the current Brazilian air transportation infrastructure, bringing a novel understanding that may help face the recent fast growth in the usage of the Brazilian transport network.

  4. Transport properties of interacting magnetic islands in tokamak plasmas

    SciTech Connect

    Gianakon, T.A.; Callen, J.D.; Hegna, C.C.

    1993-10-01

    This paper explores the equilibrium and transient transport properties of a mixed magnetic topology model for tokamak equilibria. The magnetic topology is composed of a discrete set of mostly non-overlapping magnetic islands centered on the low-order rational surfaces. Transport across the island regions is fast due to parallel transport along the stochastic magnetic field lines about the separatrix of each island. Transport between island regions is assumed to be slow due to a low residual cross-field transport. In equilibrium, such a model leads to: a nonlinear dependence of the heat flux on the pressure gradient; a power balance diffusion coefficient which increases from core to edge; and profile resiliency. Transiently, such a model also exhibits a heat pulse diffusion coefficient larger than the power balance diffusion coefficient.

  5. Structural Properties of the Brazilian Air Transportation Network.

    PubMed

    Couto, Guilherme S; da Silva, Ana Paula Couto; Ruiz, Linnyer B; Benevenuto, Fabrício

    2015-09-01

    The air transportation network in a country has a great impact on the local, national and global economy. In this paper, we analyze the air transportation network in Brazil with complex network features to better understand its characteristics. In our analysis, we built networks composed either by national or by international flights. We also consider the network when both types of flights are put together. Interesting conclusions emerge from our analysis. For instance, Viracopos Airport (Campinas City) is the most central and connected airport on the national flights network. Any operational problem in this airport separates the Brazilian national network into six distinct subnetworks. Moreover, the Brazilian air transportation network exhibits small world characteristics and national connections network follows a power law distribution. Therefore, our analysis sheds light on the current Brazilian air transportation infrastructure, bringing a novel understanding that may help face the recent fast growth in the usage of the Brazilian transport network. PMID:26312421

  6. Cabrillo College Transportation Study.

    ERIC Educational Resources Information Center

    Willett, Terrence

    This report provides results of the survey and other sources of information which have been used to develop a transportation management plan at Cabrillo College (California). In 2000, Cabrillo College organized a Transportation Management Committee to review the existing transportation situation and develop and implement a plan with the goal of…

  7. Transportation in African Development.

    ERIC Educational Resources Information Center

    Altschul, Robert D.

    1980-01-01

    Examines the structure, role, and needs of Africa's national and intracontinental transportation system. Characteristics of rail, water, road, and air transportation are examined. The conclusion is that high investment in transportation systems is essential to the development process. (Author/KC)

  8. A fast and flexible reactor physics model for simulating neutron spectra and depletion in fast reactors

    NASA Astrophysics Data System (ADS)

    Recktenwald, Geoff; Deinert, Mark

    2010-03-01

    Determining the time dependent concentration of isotopes within a nuclear reactor core is central to the analysis of nuclear fuel cycles. We present a fast, flexible tool for determining the time dependent neutron spectrum within fast reactors. The code (VBUDS: visualization, burnup, depletion and spectra) uses a two region, multigroup collision probability model to simulate the energy dependent neutron flux and tracks the buildup and burnout of 24 actinides, as well as fission products. While originally developed for LWR simulations, the model is shown to produce fast reactor spectra that show high degree of fidelity to available fast reactor benchmarks.

  9. Effects of iriflophenone 3-C-β-glucoside on fasting blood glucose level and glucose uptake

    PubMed Central

    Pranakhon, Ratree; Aromdee, Chantana; Pannangpetch, Patchareewan

    2015-01-01

    Background: One of the biological activities of agar wood (Aquilaria sinensis Lour., Thymelaeaceae), is anti-hyperglycemic activity. The methanolic extract (ME) was proven to possess the fasting blood glucose activity in rat and glucose uptake transportation by rat adipocytes. Objective: To determine the decreasing fasting blood glucose level of constituents affordable for in vivo test. If the test was positive, the mechanism which is positive to the ME, glucose transportation, will be performed. Materials and Methods: The ME was separated by column chromatography and identified by spectroscopic methods. Mice was used as an animal model (in vivo), and rat adipocytes were used for the glucose transportation activity (in vitro). Result: Iriflophenone 3-C-β-glucoside (IPG) was the main constituent, 3.17%, and tested for the activities. Insulin and the ME were used as positive controls. The ME, IPG and insulin lowered blood glucose levels by 40.3, 46.4 and 41.5%, respectively, and enhanced glucose uptake by 152, 153, and 183%, respectively. Conclusion: These findings suggest that IPG is active in lowering fasting blood glucose with potency comparable to that of insulin. PMID:25709215

  10. Modular Code and Data System for Fast Reactor Neutronics Analyses

    2008-06-30

    Version 00. The European Reactor ANalysis Optimized calculation System, ERANOS, has been developed and validated with the aim of providing a suitable basis for reliable neutronic calculations of current as well as advanced fast reactor cores. It consists of data libraries, deterministic codes and calculation procedures which have been developed within the European Collaboration on Fast Reactors over the past 20 years or so, in order to answer the needs of both industrial and R&Dmore » organisations. The whole system counts roughly 250 functions and 3000 subroutines totalling 450000 lines of FORTRAN-77 and ESOPE instructions. ERANOS is written using the ALOS software which requires only standard FORTRAN compilers and includes advanced programming features. A modular structure was adopted for easier evolution and incorporation of new functionalities. Blocks of data (SETs) can be created or used by the modules themselves or by the user via the LU control language. Programming, and dynamic memory allocation, are performed by means of the ESOPE language. External temporary storage and permanent storage capabilities are provided by the GEMAT and ARCHIVE functions, respectively. ESOPE, LU, GEMAT and ARCHIVE are all part of the ALOS software. This modular structure allows different modules to be linked together in procedures corresponding to recommended calculation routes ranging from fast-running and moderately-accurate 'routine' procedures to slow-running but highly-accurate 'reference' procedures. The main contents of the ERANOS-2.0 package are: nuclear data libraries (multigroup cross-sections from the JEF-2.2 evaluated nuclear data file, and other specific data files), a cell and lattice code (ECCO), reactor flux solvers (diffusion, Sn transport, nodal variational transport), a burn-up module, various processing modules (material and neutron balance, breeding gains,...), tools related to perturbation theory and sensitivity analysis, core follow-up modules (connected

  11. Stationary Liquid Fuel Fast Reactor

    SciTech Connect

    Yang, Won Sik; Grandy, Andrew; Boroski, Andrew; Krajtl, Lubomir; Johnson, Terry

    2015-09-30

    For effective burning of hazardous transuranic (TRU) elements of used nuclear fuel, a transformational advanced reactor concept named SLFFR (Stationary Liquid Fuel Fast Reactor) was proposed based on stationary molten metallic fuel. The fuel enters the reactor vessel in a solid form, and then it is heated to molten temperature in a small melting heater. The fuel is contained within a closed, thick container with penetrating coolant channels, and thus it is not mixed with coolant nor flow through the primary heat transfer circuit. The makeup fuel is semi- continuously added to the system, and thus a very small excess reactivity is required. Gaseous fission products are also removed continuously, and a fraction of the fuel is periodically drawn off from the fuel container to a processing facility where non-gaseous mixed fission products and other impurities are removed and then the cleaned fuel is recycled into the fuel container. A reference core design and a preliminary plant system design of a 1000 MWt TRU- burning SLFFR concept were developed using TRU-Ce-Co fuel, Ta-10W fuel container, and sodium coolant. Conservative design approaches were adopted to stay within the current material performance database. Detailed neutronics and thermal-fluidic analyses were performed to develop a reference core design. Region-dependent 33-group cross sections were generated based on the ENDF/B-VII.0 data using the MC2-3 code. Core and fuel cycle analyses were performed in theta-r-z geometries using the DIF3D and REBUS-3 codes. Reactivity coefficients and kinetics parameters were calculated using the VARI3D perturbation theory code. Thermo-fluidic analyses were performed using the ANSYS FLUENT computational fluid dynamics (CFD) code. Figure 0.1 shows a schematic radial layout of the reference 1000 MWt SLFFR core, and Table 0.1 summarizes the main design parameters of SLFFR-1000 loop plant. The fuel container is a 2.5 cm thick cylinder with an inner radius of 87.5 cm. The fuel

  12. Transport in Auxiliary Heated NSTX Discharges

    SciTech Connect

    B.P. LeBlanc; M.G. Bell; R.E. Bell; M.L. Bitte; C. Bourdelle; D.A. Gates; S.M. Kaye; R. Maingi; J.E. Menard; D. Mueller; M. Ono; S.F. Paul; M.H. Redi; A.L. Roquemore; A. Rosenberg; S.A. Sabbagh; D. Stutman; E.J. Synakowski; V.A. Soukhanovskii; J.R.Wilson

    2003-07-10

    The NSTX spherical torus (ST) provides a unique platform to investigate magnetic confinement in auxiliary-heated plasmas at low aspect ratio. Auxiliary power is routinely coupled to ohmically heated plasmas by deuterium neutral-beam injection (NBI) and by high-harmonic fast waves (HHFW) launch. While theory predicts both techniques to preferentially heat electrons, experiment reveals the electron temperature is greater than the ion temperature during HHFW, but the electron temperature is less than the ion temperature during NBI. In the following we present the experimental data and the results of transport analyses.

  13. Solitons Transport Water through Narrow Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

    Sisan, Thomas B.; Lichter, Seth

    2014-01-01

    Transformative technologies for desalination and chemical separations call for understanding molecular transport through man-made and biological nanochannels. Using numerical simulation of single-file flow of water through carbon nanotubes, we find that flow is due to fast-moving density variations (solitons) that are additive so flow rate is proportional to number of solitons. Simulation results match predictions from a theoretical model for soliton propagation. From 1-300 K flow rates increase as temperature decreases. Our results build a fundamentally new understanding of nanochannel flows and suggest new principles for the design of nanoscale devices.

  14. Solitons transport water through narrow carbon nanotubes.

    PubMed

    Sisan, Thomas B; Lichter, Seth

    2014-01-31

    Transformative technologies for desalination and chemical separations call for understanding molecular transport through man-made and biological nanochannels. Using numerical simulation of single-file flow of water through carbon nanotubes, we find that flow is due to fast-moving density variations (solitons) that are additive so flow rate is proportional to number of solitons. Simulation results match predictions from a theoretical model for soliton propagation. From 1-300 K flow rates increase as temperature decreases. Our results build a fundamentally new understanding of nanochannel flows and suggest new principles for the design of nanoscale devices.

  15. Theory of contributon transport

    SciTech Connect

    Painter, J.W.; Gerstl, S.A.W.; Pomraning, G.C.

    1980-10-01

    A general discussion of the physics of contributon transport is presented. To facilitate this discussion, a Boltzmann-like transport equation for contributons is obtained, and special contributon cross sections are defined. However, the main goal of this study is to identify contributon transport equations and investigate possible deterministic solution techniques. Four approaches to the deterministic solution of the contributon transport problem are investigated. These approaches are an attempt to exploit certain attractive properties of the contributon flux, psi = phi phi/sup +/, where phi and phi/sup +/ are the solutions to the forward and adjoint Boltzmann transport equations.

  16. Pharmacology of Iron Transport

    PubMed Central

    Byrne, Shaina L.; Krishnamurthy, Divya; Wessling-Resnick, Marianne

    2013-01-01

    Elucidating the molecular basis for the regulation of iron uptake, storage, and distribution is necessary to understand iron homeostasis. Pharmacological tools are emerging to identify and distinguish among different iron transport pathways. Stimulatory or inhibitory small molecules with effects on iron uptake can help characterize the mechanistic elements of iron transport and the roles of the transporters involved in these processes. In particular, iron chelators can serve as potential pharmacological tools to alleviate diseases of iron overload. This review focuses on the pharmacology of iron transport, introducing iron transport membrane proteins and known inhibitors. PMID:23020294

  17. Transportation Business Plan

    SciTech Connect

    Not Available

    1986-01-01

    The Transportation Business Plan is a step in the process of procuring the transportation system. It sets the context for business strategy decisions by providing pertinent background information, describing the legislation and policies governing transportation under the NWPA, and describing requirements of the transportation system. Included in the document are strategies for procuring shipping casks and transportation support services. In the spirit of the NWPA directive to utilize the private sector to the maximum extent possible, opportunities for business ventures are obvious throughout the system development cycle.

  18. Fast-mode magnetohydrodynamic waves in coronal holes and the solar wind

    NASA Technical Reports Server (NTRS)

    Fla, T.; Habbal, S. R.; Holzer, T. E.; Leer, E.

    1984-01-01

    Fast-mode MHD waves in the solar corona can propagate in any direction relative to the background magnetic field. In coronal holes, they refract into regions of low Alfven speed and are relatively difficult to damp. These characteristics lead to the possibility that fast-mode waves transport energy from magnetically closed coronal regions into coronal holes, that they are refracted into the central regions of coronal holes, and that they deposit most of their energy in the region of supersonic flow of high-speed solar wind streams emanating from coronal holes. To investigate whether this possibility might be realized and fast-mode waves might play a significant role in driving high-speed streams, a parameter study is carried out to examine the propagation and damping of fast-mode waves in various coronal hole models. This study indicates a broad range of coronal hole parameters for which fast-mode waves can play such a role and emphasizes the need for an improved knowledge of large-scale coronal magnetic structure, which is required before any firm conclusions can be drawn.

  19. Fast electron current density profile and diffusion studies during LHCD in PBX-M

    SciTech Connect

    Jones, S.E.; Kesner, J.; Luckhardt, S.; Paoletti, F.; von Goeler, S.; Bernabei, S.; Kaita, R.; Rimini, F.

    1993-08-01

    Successful current profile control experiments using lower hybrid current drive (LCHD) clearly require knowledge of (1) the location of the driven fast electrons and (2) the ability to maintain that location from spreading due to radial diffusion. These issues can be addressed by examining the data from the hard x-ray camera on PBX-M, a unique diagnostic producing two-dimensional, time resolved tangential images of fast electron bremsstrahlung. Using modeling, these line-of-sight images are inverted to extract a radial fast electron current density profile. We note that ``hollow`` profiles have been observed, indicative of off-axis current drive. These profiles can then be used to calculate an upper bound for an effective fast electron diffusion constant: assuming an extremely radially narrow lower hybrid absorption profile and a transport model based on Rax and Moreau, a model fast electron current density profile is calculated and compared to the experimentally derived profile. The model diffusion constant is adjusted until a good match is found. Applied to steady-state quiescent modes on PBX-M, we obtain an upper limit for an effective diffusion constant of about D*=1.1 m{sup 2}/sec.

  20. Fish protein intake induces fast-muscle hypertrophy and reduces liver lipids and serum glucose levels in rats.

    PubMed

    Kawabata, Fuminori; Mizushige, Takafumi; Uozumi, Keisuke; Hayamizu, Kohsuke; Han, Li; Tsuji, Tomoko; Kishida, Taro

    2015-01-01

    In our previous study, fish protein was proven to reduce serum lipids and body fat accumulation by skeletal muscle hypertrophy and enhancing basal energy expenditure in rats. In the present study, we examined the precise effects of fish protein intake on different skeletal muscle fiber types and metabolic gene expression of the muscle. Fish protein increased fast-twitch muscle weight, reduced liver triglycerides and serum glucose levels, compared with the casein diet after 6 or 8 weeks of feeding. Furthermore, fish protein upregulated the gene expressions of a fast-twitch muscle-type marker and a glucose transporter in the muscle. These results suggest that fish protein induces fast-muscle hypertrophy, and the enhancement of basal energy expenditure by muscle hypertrophy and the increase in muscle glucose uptake reduced liver lipids and serum glucose levels. The present results also imply that fish protein intake causes a slow-to-fast shift in muscle fiber type.