WorldWideScience

Sample records for current drive capability

  1. On the Current Drive Capability of Low Dimensional Semiconductors: 1D versus 2D

    Science.gov (United States)

    Zhu, Y.; Appenzeller, J.

    2015-10-01

    Low-dimensional electronic systems are at the heart of many scaling approaches currently pursuit for electronic applications. Here, we present a comparative study between an array of one-dimensional (1D) channels and its two-dimensional (2D) counterpart in terms of current drive capability. Our findings from analytical expressions derived in this article reveal that under certain conditions an array of 1D channels can outperform a 2D field-effect transistor because of the added degree of freedom to adjust the threshold voltage in an array of 1D devices.

  2. On the Current Drive Capability of Low Dimensional Semiconductors: 1D versus 2D.

    Science.gov (United States)

    Zhu, Y; Appenzeller, J

    2015-12-01

    Low-dimensional electronic systems are at the heart of many scaling approaches currently pursuit for electronic applications. Here, we present a comparative study between an array of one-dimensional (1D) channels and its two-dimensional (2D) counterpart in terms of current drive capability. Our findings from analytical expressions derived in this article reveal that under certain conditions an array of 1D channels can outperform a 2D field-effect transistor because of the added degree of freedom to adjust the threshold voltage in an array of 1D devices.

  3. Capabilities of the ITER Electron Cyclotron Equatorial Launcher for Heating and Current Drive

    Directory of Open Access Journals (Sweden)

    Ramponi G.

    2012-09-01

    Full Text Available The ITER Electron Cyclotron Equatorial Launcher is designed to be one of the heating systems to assist and sustain the development of various ITER plasma scenarios starting with the very first plasma operation. Here the capabilities for Heating and Current Drive of this system are reviewed. In particular, the optimum launching conditions are investigated for two scenarios at burn, comparing toroidal and poloidal steering options. Then, the EC capabilities are investigated for different plasma parameters corresponding to various phases of the ITER plasma discharge, from current ramp-up up to burn, and for a wide range of magnetic field, focusing in particular on the EC potential for heating and for L to H-mode assist. It is found that the EC system can contribute to a wide range of heating scenarios during the ramp-up of the magnetic field, significantly increasing the applicable range as a function of magnetic field.

  4. Studies of challenge in lower hybrid current drive capability at high density regime in experimental advanced superconducting tokamak

    Science.gov (United States)

    Ding, B. J.; Li, M. H.; Li, Y. C.; Wang, M.; Liu, F. K.; Shan, J. F.; Li, J. G.; Wan, B. N.; Wan

    2017-02-01

    Aiming at a fusion reactor, two issues must be solved for the lower hybrid current drive (LHCD), namely good lower hybrid wave (LHW)-plasma coupling and effective current drive at high density. For this goal, efforts have been made to improve LHW-plasma coupling and current drive capability at high density in experimental advanced superconducting tokamak (EAST). LHW-plasma coupling is improved by means of local gas puffing and gas puffing from the electron side is taken as a routine way for EAST to operate with LHCD. Studies of high density experiments suggest that low recycling and high lower hybrid (LH) frequency are preferred for LHCD experiments at high density, consistent with previous results in other machines. With the combination of 2.45 GHz and 4.6 GHz LH waves, a repeatable high confinement mode plasma with maximum density up to 19~\\text{m}-3$ was obtained by LHCD in EAST. In addition, in the first stage of LHCD cyclic operation, an alternative candidate for more economical fusion reactors has been demonstrated in EAST and further work will be continued.

  5. Turbulent current drive mechanisms

    Science.gov (United States)

    McDevitt, Christopher J.; Tang, Xian-Zhu; Guo, Zehua

    2017-08-01

    Mechanisms through which plasma microturbulence can drive a mean electron plasma current are derived. The efficiency through which these turbulent contributions can drive deviations from neoclassical predictions of the electron current profile is computed by employing a linearized Coulomb collision operator. It is found that a non-diffusive contribution to the electron momentum flux as well as an anomalous electron-ion momentum exchange term provide the most efficient means through which turbulence can modify the mean electron current for the cases considered. Such turbulent contributions appear as an effective EMF within Ohm's law and hence provide an ideal means for driving deviations from neoclassical predictions.

  6. Turbulent current drive

    Science.gov (United States)

    Garbet, X.; Esteve, D.; Sarazin, Y.; Dif-Pradalier, G.; Ghendrih, P.; Grandgirard, V.; Latu, G.; Smolyakov, A.

    2014-11-01

    The Ohm's law is modified when turbulent processes are accounted for. Besides an hyper-resistivity, already well known, pinch terms appear in the electron momentum flux. Moreover it appears that turbulence is responsible for a source term in the Ohm's law, called here turbulent current drive. Two terms contribute to this source. The first term is a residual stress in the momentum flux, while the second contribution is an electro-motive force. A non zero average parallel wave number is needed to get a finite source term. Hence a symmetry breaking mechanism must be invoked, as for ion momentum transport. E × B shear flows and turbulence intensity gradients are shown to provide similar contributions. Moreover this source term has to compete with the collision friction term (resistivity). The effect is found to be significant for a large scale turbulence in spite of an unfavorable scaling with the ratio of the electron to ion mass. Turbulent current drive appears to be a weak effect in the plasma core, but could be substantial in the plasma edge where it may produce up to 10 % of the local current density.

  7. Non-inductive current drive

    NARCIS (Netherlands)

    Westerhof, E.

    2012-01-01

    This lecture addresses the various ways of non-inductive current generation. In particular, the topics covered include the bootstrap current, RF current drive, neutral beam current drive, alternative methods, and possible synergies between different ways of non-inductive current generation.

  8. NON-INDUCTIVE CURRENT DRIVE

    NARCIS (Netherlands)

    Westerhof, E.

    2010-01-01

    This lecture addresses the various ways of non-inductive current generation. In particular, the topics covered include the bootstrap current, RF current drive, neutral beam current drive, alternative methods, and possible synergies between different ways of non-inductive current generation.

  9. Electron cyclotron heating and current drive

    NARCIS (Netherlands)

    Westerhof, E.

    1996-01-01

    Plasma heating and non-inductive current drive by waves in the electron cyclotron range of frequencies are reviewed. Both theoretical aspects concerning wave properties, heating and current drive mechanisms, as well as the major experimental results are summarized.

  10. Approach to Developing Predictive Capability for Hohlraum Drive and Symmetry

    Energy Technology Data Exchange (ETDEWEB)

    Jones, O. S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-07-22

    Currently, we do not have the ability to predict the hohlraum drive and symmetry without requiring ad hoc adjustments to physics models. This document describes a plan for code improvements and focused physics validation experiments.

  11. Current drive induced by intermittent trapping

    Energy Technology Data Exchange (ETDEWEB)

    Nakach, R. [Association Euratom-CEA, CEA/Cadarache, Dept. de Recherches sur la Fusion Controlee (DRFC), 13 - Saint-Paul-lez-Durance (France); Gell, Y. [CET, Israel (Israel)

    1999-02-01

    We propose a mechanism for driving a current in a dispersive plasma based on intermittent trapping of electrons in a ponderomotive well generated by two- counterpropagating electron cyclotron waves. By choosing properly the parameters of the system, this mechanism is expected to induce a high efficiency current drive. (authors)

  12. Electron cyclotron resonance heating and current drive

    Energy Technology Data Exchange (ETDEWEB)

    Fidone, I.; Castejon, F.

    1992-07-01

    A brief summary of the theory and experiments on electron- cyclotron heating and current drive is presented. The general relativistic formulation of wave propagation and linear absorption is considered in some detail. The O-mode and the X-mode for normal and oblique propagation are investigated and illustrated by several examples. The experimental verification of the theory in T-10 and D- III-D is briefly discussed. Quasilinear evolution of the momentum distribution and related applications as, for instance, non linear wave, damping and current drive, are also considered for special cases of wave frequencies, polarization and propagation. In the concluding section we present the general formulation of the wave damping and current drive in the absence of electron trapping for arbitrary values of the wave frequency. (Author) 13 refs.

  13. ITER (International Thermonuclear Experimental Reactor) current drive and heating physics

    Energy Technology Data Exchange (ETDEWEB)

    Nevins, W.M.; Lindquist, W. (Lawrence Livermore National Lab., CA (USA)); Fujisawa, N.; Kimura, H. (Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan)); Hopman, H.; Rebuffi, L.; Wegrowe, J.G. (Max-Planck-Institut fuer Plasmaphysik, Garching (Germany, F.R.). NET Design Team); Parail, V.; Vdovin, V. (Gosudarstvennyj Komitet po Ispol' zovaniyu Atomnoj Ehnergii SSSR, Moscow (USSR). Inst. Atomnoj Ehn

    1990-01-01

    The ITER Current Drive and Heating (CD H) systems are required for: Ionization and current initiation; Non-inductive current ramp-up assist; Heating of the plasma; Steady-state operation with full non-inductive current drive; Current profile control; and Burn control by modulation of the auxiliary power. Steady-state current drive is the most demanding requirement, so this has driven the choice of the ITER current drive and heating systems.

  14. Lower Hybrid Current Drive in Tore Supra

    Energy Technology Data Exchange (ETDEWEB)

    Ekedahl, A.; Goniche, M.; Guilhem, D.; Kazarian, F.; Peysson, Y. and Tore Supra Team [CEA, IRFM, F-13108 St Paul Les Durance, (France)

    2009-07-01

    Since the mission of Tore Supra is to produce quasi-steady-state discharges, the lower hybrid current drive (LHCD) system constitutes the most important method of additional hewing and noninductive current drive. A description of the LHCD is given, including the different launcher designs developed for the Tore Supra long-pulse program. Following the completion of the Composants Internes et Limiteur project, together with the installation of a high-performance LHCD launcher, world record discharges, injected and extracted energy exceeding 1 GJ, were obtained in 2003. With the flexibility of lower hybrid (LH) waves to tailor the current profile, an enhanced performance regime, the so-called LHEP has been maintained in quasi-steady-state discharges. Detailed measurements of the fast electron distribution have allowed us to constrain LHCD ray-tracing models and to quantify parametric dependencies describing the fast electron tail. Localized heat loads oil the LHCD launchers due to interaction with fast particles have been measured and quantified, using infrared imaging and calorimetric measurements oil water-cooled plasma facing components. Furthermore, experimental results in the area of LH wave coupling are presented. (authors)

  15. Current drive for stability of thermonuclear plasma reactor

    Science.gov (United States)

    Amicucci, L.; Cardinali, A.; Castaldo, C.; Cesario, R.; Galli, A.; Panaccione, L.; Paoletti, F.; Schettini, G.; Spigler, R.; Tuccillo, A.

    2016-01-01

    To produce in a thermonuclear fusion reactor based on the tokamak concept a sufficiently high fusion gain together stability necessary for operations represent a major challenge, which depends on the capability of driving non-inductive current in the hydrogen plasma. This request should be satisfied by radio-frequency (RF) power suitable for producing the lower hybrid current drive (LHCD) effect, recently demonstrated successfully occurring also at reactor-graded high plasma densities. An LHCD-based tool should be in principle capable of tailoring the plasma current density in the outer radial half of plasma column, where other methods are much less effective, in order to ensure operations in the presence of unpredictably changes of the plasma pressure profiles. In the presence of too high electron temperatures even at the periphery of the plasma column, as envisaged in DEMO reactor, the penetration of the coupled RF power into the plasma core was believed for long time problematic and, only recently, numerical modelling results based on standard plasma wave theory, have shown that this problem should be solved by using suitable parameter of the antenna power spectrum. We show here further information on the new understanding of the RF power deposition profile dependence on antenna parameters, which supports the conclusion that current can be actively driven over a broad layer of the outer radial half of plasma column, thus enabling current profile control necessary for the stability of a reactor.

  16. ICRF fast wave current drive and mode conversion current drive in EAST tokamak

    Science.gov (United States)

    Yin, L.; Yang, C.; Gong, X. Y.; Lu, X. Q.; Du, D.; Chen, Y.

    2017-10-01

    Fast wave in the ion-cyclotron resonance frequency (ICRF) range is a promising candidate for non-inductive current drive (CD), which is essential for long pulse and high performance operation of tokamaks. A numerical study on the ICRF fast wave current drive (FWCD) and mode-conversion current drive (MCCD) in the Experimental Advanced Superconducting Tokamak (EAST) is carried out by means of the coupled full wave and Ehst-Karney parameterization methods. The results show that FWCD efficiency is notable in two frequency regimes, i.e., f ≥ 85 MHz and f = 50-65 MHz, where ion cyclotron absorption is effectively avoided, and the maximum on-axis driven current per unit power can reach 120 kA/MW. The sensitivity of the CD efficiency to the minority ion concentration is confirmed, owing to fast wave mode conversion, and the peak MCCD efficiency is reached for 22% minority-ion concentration. The effects of the wave-launch position and the toroidal wavenumber on the efficiency of current drive are also investigated.

  17. TOKAMAK EQUILIBRIA WITH CENTRAL CURRENT HOLES AND NEGATIVE CURRENT DRIVE

    Energy Technology Data Exchange (ETDEWEB)

    CHU, M.S.; PARKS, P.B.

    2002-06-01

    OAK B202 TOKAMAK EQUILIBRIA WITH CENTRAL CURRENT HOLES AND NEGATIVE CURRENT DRIVE. Several tokamak experiments have reported the development of a central region with vanishing currents (the current hole). Straightforward application of results from the work of Greene, Johnson and Weimer [Phys. Fluids, 3, 67 (1971)] on tokamak equilibrium to these plasmas leads to apparent singularities in several physical quantities including the Shafranov shift and casts doubts on the existence of this type of equilibria. In this paper, the above quoted equilibrium theory is re-examined and extended to include equilibria with a current hole. It is shown that singularities can be circumvented and that equilibria with a central current hole do satisfy the magnetohydrodynamic equilibrium condition with regular behavior for all the physical quantities and do not lead to infinitely large Shafranov shifts. Isolated equilibria with negative current in the central region could exist. But equilibria with negative currents in general do not have neighboring equilibria and thus cannot have experimental realization, i.e. no negative currents can be driven in the central region.

  18. Current Drive in a Ponderomotive Potential with Sign Reversal

    Energy Technology Data Exchange (ETDEWEB)

    N.J. Fisch; J.M. Rax; I.Y. Dodin

    2003-07-30

    Noninductive current drive can be accomplished through ponderomotive forces with high efficiency when the potential changes sign over the interaction region. The effect can practiced upon both ions and electrons. The current drive efficiencies, in principle, might be higher than those possible with conventional radio-frequency current-drive techniques, since different considerations come into play.

  19. Current Drive in a Ponderomotive Potential with Sign Reversal

    CERN Document Server

    Fisch, N J; Rax, J M

    2003-01-01

    Noninductive current drive can be accomplished through ponderomotive forces with high efficiency when the potential changes sign over the interaction region. The effect can practiced upon both ions and electrons. The current drive efficiencies, in principle, might be higher than those possible with conventional radio-frequency current-drive techniques, since different considerations come into play.

  20. How dynamic capabilities drive performance in the Indian IT industry

    DEFF Research Database (Denmark)

    Holzweber, Markus; Mattsson, Jan; Chadee, Doren;

    2012-01-01

    This study examines key issues and effects of capability management on a fast-growing area of knowledge-intensive global business services – IT outsourcing and offshoring. An exploratory study of Indian companies providing complex process-oriented offshore IT services to their global customers...... is undertaken. The analysis of the data related to the service provider side shows that developing dynamic capabilities is strongly driven by management and top-clients and results in the development of business processes and in establishing a strategic partnership with the client organization. Key findings...

  1. Electron cyclotron heating and current drive in toroidal geometry

    Energy Technology Data Exchange (ETDEWEB)

    Kritz, A.H.

    1991-11-01

    The Principal Investigator has continued to work on problems associated both with the deposition and with the emission of electron cyclotron power in toroidal plasmas. We have investigated the use of electron cyclotron resonance heating for bringing compact tokamaks (BPX) to ignition-like parameters. This requires that we continue to refine the modeling capability of the TORCH code linked with the BALDUR 1 {1/2} D transport code. Using this computational tool, we have examined the dependence of ignition on heating and transport employing both theoretical (multi-mode) and empirically based transport models. The work on current drive focused on the suppression of tearing modes near the q = 2 surface and sawteeth near the q = 1 surface. Electron cyclotron current drive in CIT near the q =2 surface was evaluated for a launch scenario where electron cyclotron power was launched near the equatorial plane. The work on suppression of sawteeth has been oriented toward understanding the suppression that has been observed in a number of tokamaks, in particular, in the WT-3 tokamak in Kyoto. To evaluate the changes in current profile (shear) near the q =1 surface, simulations have been carried out using the linked BALDUR-TORCH code. We consider effects on shear resulting both from wave-induced current as well as from changes in conductivity associated with changes in local temperature. Abstracts and a paper relating to this work is included in Appendix A.

  2. Bubble Radiation Detection: Current and Future Capability

    Energy Technology Data Exchange (ETDEWEB)

    AJ Peurrung; RA Craig

    1999-11-15

    Despite a number of noteworthy achievements in other fields, superheated droplet detectors (SDDs) and bubble chambers (BCs) have not been used for nuclear nonproliferation and arms control. This report examines these two radiation-detection technologies in detail and answers the question of how they can be or should be ''adapted'' for use in national security applications. These technologies involve closely related approaches to radiation detection in which an energetic charged particle deposits sufficient energy to initiate the process of bubble nucleation in a superheated fluid. These detectors offer complete gamma-ray insensitivity when used to detect neutrons. They also provide controllable neutron-energy thresholds and excellent position resolution. SDDs are extraordinarily simple and inexpensive. BCs offer the promise of very high efficiency ({approximately}75%). A notable drawback for both technologies is temperature sensitivity. As a result of this problem, the temperature must be controlled whenever high accuracy is required, or harsh environmental conditions are encountered. The primary findings of this work are listed and briefly summarized below: (1) SDDs are ready to function as electronics-free neutron detectors on demand for arms-control applications. The elimination of electronics at the weapon's location greatly eases the negotiability of radiation-detection technologies in general. (2) As a result of their high efficiency and sharp energy threshold, current BCs are almost ready for use in the development of a next-generation active assay system. Development of an instrument based on appropriately safe materials is warranted. (3) Both kinds of bubble detectors are ready for use whenever very high gamma-ray fields must be confronted. Spent fuel MPC and A is a good example where this need presents itself. (4) Both kinds of bubble detectors have the potential to function as low-cost replacements for conventional neutron

  3. Current European developments in solar paddle drives

    Science.gov (United States)

    Bentall, R. H.

    1973-01-01

    The European Space Research and Technology Centre (ESTEC) is sponsoring the development of a number of critical spacecraft hardware items. The hardware under development includes two competing solar paddle drives which are being produced to similar specifications. Three mechanisms of each type are being produced and will undergo thermal vacuum testing. All mechanisms have lead lubricated bearings.

  4. Theoretical studies of non inductive current drive in compact toroids

    NARCIS (Netherlands)

    Farengo, R; Lifschitz, AF; Caputi, KI; Arista, NR; Clemente, RA

    2002-01-01

    Three non inductive current drive methods that can be applied to compact toroids axe studied. The use of neutral beams to drive current in field reversed configurations and spheromaks is studied using a Monte Carlo code that includes a complete ionization package and follows the exact particle orbit

  5. Characterization of Input Current Interharmonics in Adjustable Speed Drives

    DEFF Research Database (Denmark)

    Soltani, Hamid; Davari, Pooya; Zare, Firuz

    2017-01-01

    -edge symmetrical regularly sampled Space Vector Modulation (SVM) technique, on the input current interharmonic components are presented and discussed. Particular attention is also given to the influence of the asymmetrical regularly sampled modulation technique on the drive input current interharmonics...

  6. Sensorless optimal sinusoidal brushless direct current for hard disk drives

    Science.gov (United States)

    Soh, C. S.; Bi, C.

    2009-04-01

    Initiated by the availability of digital signal processors and emergence of new applications, market demands for permanent magnet synchronous motors have been surging. As its back-emf is sinusoidal, the drive current should also be sinusoidal for reducing the torque ripple. However, in applications like hard disk drives, brushless direct current (BLDC) drive is adopted instead of sinusoidal drive for simplification. The adoption, however, comes at the expense of increased harmonics, losses, torque pulsations, and acoustics. In this paper, we propose a sensorless optimal sinusoidal BLDC drive. First and foremost, the derivation for an optimal sinusoidal drive is presented, and a power angle control scheme is proposed to achieve an optimal sinusoidal BLDC. The scheme maintains linear relationship between the motor speed and drive voltage. In an attempt to execute the sensorless drive, an innovative power angle measurement scheme is devised, which takes advantage of the freewheeling diodes and measures the power angle through the detection of diode voltage drops. The objectives as laid out will be presented and discussed in this paper, supported by derivations, simulations, and experimental results. The proposed scheme is straightforward, brings about the benefits of sensorless sinusoidal drive, negates the need for current sensors by utilizing the freewheeling diodes, and does not incur additional cost.

  7. High Harmonic Fast Wave heating and current drive for NSTX

    Science.gov (United States)

    Robinson, J. A.; Majeski, R.; Hosea, J.; Menard, J.; Ono, M.; Phillips, C. K.; Wilson, J. R.; Wright, J.; Batchelor, D. B.; Carter, M. D.; Jaeger, E. F.; Ryan, P.; Swain, D.; Mau, T. K.; Chiu, S. C.; Smithe, D.

    1997-11-01

    Heating and noninductive current drive in NSTX will initially use 6 MW of rf power in the high harmonic fast wave (HHFW) regime. We present numerical modelling of HHFW heating and current drive in NSTX using the PICES, CURRAY, FISIC, and METS95 codes. High electron β during the discharge flattop in NSTX is predicted to result in off-axis power deposition and current drive. However, reductions in the trapped electron fraction (due also to high β effects) are predicted to result in adequate current drive efficiency, with ~ 400 - 500 kA of noninductive current driven. Sufficient per-pass absorption (>10%) to ensure effective electron heating is also expected for the startup plasma. Present plans call for a single twelve strap antenna driven by six FMIT transmitters operating at 30 MHz. The design for the antenna and matching system will also be discussed.

  8. Plasma heating and current drive using intense, pulsed microwaves

    Energy Technology Data Exchange (ETDEWEB)

    Cohen, B.I.; Cohen, R.H.; Nevins, W.M.; Rognlien, T.D.; Bonoli, P.T.; Porkolab, M.

    1988-01-01

    The use of powerful new microwave sources, e.g., free-electron lasers and relativistic gyrotrons, provide unique opportunities for novel heating and current-drive schemes in the electron-cyclotron and lower-hybrid ranges of frequencies. These high-power, pulsed sources have a number of technical advantages over conventional, low-intensity sources; and their use can lead to improved current-drive efficiencies and better penetration into a reactor-grade plasma in specific cases. The Microwave Tokamak Experiment at Lawrence Livermore National Laboratory will provide a test for some of these new heating and current-drive schemes. This paper reports theoretical progress both in modeling absorption and current drive for intense pulses and in analyzing some of the possible complications that may arise, e.g., parametric instabilities and nonlinear self-focusing. 22 refs., 9 figs., 1 tab.

  9. Langmuir probe study in the nonresonant current drive regime of helicon discharge

    Indian Academy of Sciences (India)

    Manash Kumar Paul; Dhiraj Bora

    2008-07-01

    Characterization of the current drive regime is done for helicon wave-generated plasma in a torus, at a very high operating frequency. A radiofrequency-compensated Langmuir probe is designed and used for the measurement of plasma parameters along with the electron energy distributions in radial scans of the plasma. The electron energy distribution patterns obtained in the operational regime suggest that Landau damping cannot be responsible for the efficient helicon discharge in the present study. A typical peaked radial density profile, high plasma temperature and absence of an appreciable amount of energetic electrons for resonant wave–particle interactions, suggest that the chosen operational regime is suitable for the study of nonresonant current drive by helicon wave. Successful and significant current drive achieved in our device clearly demonstrates the capability of nonresonant current drive by helicon waves in the present operational regime.

  10. Low Cost Sensors-Current Capabilities and Gaps

    Science.gov (United States)

    1. Present the findings from the a recent technology review of gas and particulate phase sensors 2. Focus on the lower-cost sensors 3. Discuss current capabilities, estimated range of measurement, selectivity, deployment platforms, response time, and expected range of acceptabl...

  11. Advanced induction motor drive control with single current sensor

    Directory of Open Access Journals (Sweden)

    Adžić Evgenije M.

    2016-01-01

    Full Text Available This paper proposes induction motor drive control method which uses minimal number of sensors, providing only DC-link current as a feedback signal. Improved DC-link current sampling scheme and modified asymmetrical switching pattern cancels characteristic waveform errors which exist in all three reconstructed motor line-currents. Motor linecurrent harmonic content is reduced to an acceptable level, eliminating torque and speed oscillations which were inherent for conventional single sensor drives. Consequently, use of single current sensor and line-current reconstruction technique is no longer acceptable only for low and medium performance drives, but also for drives where priority is obtaining a highly accurate, stable and fast response. Proposed control algorithm is validated using induction motor drive hardware prototype based on TMS320F2812 digital signal processor. [Projekat Ministarstva nauke Republike Srbije, br. III 042004 and by the Provincial Secretariat for Science and Technological Development of AP Vojvodina under contract No. 114-451-3508/2013-04

  12. Current drive experiments in the Helicity Injected Torus - II

    Science.gov (United States)

    Hamp, W. T.; Redd, A. J.; Jarboe, T. R.; Nelson, B. A.; O'Neill, R. G.; Raman, R.; Sieck, P. E.; Smith, R. J.; Mueller, D.

    2006-10-01

    The HIT-II spherical torus (ST) device has demonstrated four toroidal plasma current drive configurations to form and sustain a tokamak: 1) inductive (ohmic) current drive, 2) coaxial helicity injection (CHI) current drive, 3) CHI initiated plasmas with ohmic sustainment (CHI+OH), and 4) ohmically initiated plasmas with CHI edge current drive (OH+ECD). CHI discharges with a sufficiently high ratio of injector current to toroidal field current form a closed flux core, and amplify the injector poloidal flux through magnetic reconnection. CHI+OH plasmas are more robust than unassisted ohmic discharges, with a wider operating space and more efficient use of the transformer Volt-seconds. Finally, edge CHI can enhance the plasma current of an ohmic discharge without significantly degrading the quality of the discharge. Results will be presented for each HIT-II operating regime, including empirical performance scalings, applicable parametric operating spaces, and requirements to produce these discharges. Thomson scattering measurements and EFIT simulations are used to evaluate confinement in several representative plasmas. Finally, we outline extensions to the HIT-II CHI studies that could be performed with NSTX, SUNIST, or other ST devices.

  13. High-current cyclotron to drive an electronuclear assembly

    CERN Document Server

    Alenitsky, Yu G

    2002-01-01

    The proposal on creation of a high-current cyclotron complex for driving an electronuclear assembly reported at the 17th Meeting on Accelerators of Charged Particles is discussed. Some changes in the basic design parameters of the accelerator are considered in view of new results obtained in the recent works. It is shown that the cyclotron complex is now the most real and cheapest accelerator for production of proton beams with a power of up to 10 MW. Projects on design of a high-current cyclotron complex for driving an electronuclear subcritical assembly are presented.

  14. Testing of an Arcjet Thruster with Capability of Direct-Drive Operation

    Science.gov (United States)

    Martin, Adam K.; Polzin, Kurt A.; Eskridge, Richard H.; Smith, James W.; Schoenfeld, Michael P.; Riley, Daniel P.

    2015-01-01

    Electric thrusters typically require a power processing unit (PPU) to convert the spacecraft provided power to the voltage-current that a thruster needs for operation. Testing has been initiated to study whether an arcjet thruster can be operated directly with the power produced by solar arrays without any additional conversion. Elimination of the PPU significantly reduces system-level complexity of the propulsion system, and lowers developmental cost and risk. The work aims to identify and address technical questions related to power conditioning and noise suppression in the system and heating of the thruster in long-duration operation. The apparatus under investigation has a target power level from 400-1,000 W. However, the proposed direct-drive arcjet is potentially a highly scalable concept, applicable to solar-electric spacecraft with up to 100's of kW and beyond. A direct-drive electric propulsion system would be comprised of a thruster that operates with the power supplied directly from the power source (typically solar arrays) with no further power conditioning needed between those two components. Arcjet thrusters are electric propulsion devices, with the power supplied as a high current at low voltage; of all the different types of electric thruster, they are best suited for direct drive from solar arrays. One advantage of an arcjet over Hall or gridded ion thrusters is that for comparable power the arcjet is a much smaller device and can provide more thrust and orders of magnitude higher thrust density (approximately 1-10 N/sq m), albeit at lower I(sub sp) (approximately 800-1000 s). In addition, arcjets are capable of operating on a wide range of propellant options, having been demonstrated on H2, ammonia, N2, Ar, Kr, Xe, while present SOA Hall and ion thrusters are primarily limited to Xe propellant. Direct-drive is often discussed in terms of Hall thrusters, but they require 250-300 V for operation, which is difficult even with high-voltage solar

  15. Research on Predicting Drive Current of Shipborne Satcom Antenna

    Directory of Open Access Journals (Sweden)

    Kong Jinping

    2015-01-01

    Full Text Available Predicting the effect of antenna wind load on servo system precisely is meaningful to ensure the safety of satcom antenna on operation, which can avoid overload operation. In this paper, the computational fluid dynamics is used to proceed numerical computation on the pressure distribution of the reflector and torque of drive shaft under different wind speed, windward angle and angle of pitch of the antenna. The simulation model is built under MATLAB/Simulink simulation environment, and the drive current of the antenna servo system is analyzed under wind load effect and ship swing. Then, a method of predicting drive current of antenna servo system according to the wind speed, wind direction and attitude of the antenna is concluded. And this method is verified by simulation at last.

  16. Alternating-Current Motor Drive for Electric Vehicles

    Science.gov (United States)

    Krauthamer, S.; Rippel, W. E.

    1982-01-01

    New electric drive controls speed of a polyphase as motor by varying frequency of inverter output. Closed-loop current-sensing circuit automatically adjusts frequency of voltage-controlled oscillator that controls inverter frequency, to limit starting and accelerating surges. Efficient inverter and ac motor would give electric vehicles extra miles per battery charge.

  17. Disturbance observer based current controller for vector controlled IM drives

    DEFF Research Database (Denmark)

    Teodorescu, Remus; Dal, Mehmet

    2008-01-01

    In order to increase the accuracy of the current control loop, usually, well known parameter compensation and/or cross decoupling techniques are employed for advanced ac drives. In this paper, instead of using these techniques an observer-based current controller is proposed for vector controlled...... coupling effects and increase robustness against parameters change without requiring any other compensation strategies. The experimental implementation results are provided to demonstrate validity and performance of the proposed control scheme.......In order to increase the accuracy of the current control loop, usually, well known parameter compensation and/or cross decoupling techniques are employed for advanced ac drives. In this paper, instead of using these techniques an observer-based current controller is proposed for vector controlled...

  18. Study of lower hybrid current drive for the demonstration reactor

    Energy Technology Data Exchange (ETDEWEB)

    Molavi-Choobini, Ali Asghar [Dept. of Physics, Faculty of Engineering, Islamic Azad University, Shahr-e-kord Branch, Shahr-e-kord (Iran, Islamic Republic of); Naghidokht, Ahmed [Dept. of Physics, Urmia University, Urmia (Iran, Islamic Republic of); Karami, Zahra [Dept. of Engineering, Islamic Azad University, Zanjan Branch, Zanjan (Iran, Islamic Republic of)

    2016-06-15

    Steady-state operation of a fusion power plant requires external current drive to minimize the power requirements, and a high fraction of bootstrap current is required. One of the external sources for current drive is lower hybrid current drive, which has been widely applied in many tokamaks. Here, using lower hybrid simulation code, we calculate electron distribution function, electron currents and phase velocity changes for two options of demonstration reactor at the launched lower hybrid wave frequency 5 GHz. Two plasma scenarios pertaining to two different demonstration reactor options, known as pulsed (Option 1) and steady-state (Option 2) models, have been analyzed. We perceive that electron currents have major peaks near the edge of plasma for both options but with higher efficiency for Option 1, although we have access to wider, more peripheral regions for Option 2. Regarding the electron distribution function, major perturbations are at positive velocities for both options for flux surface 16 and at negative velocities for both options for flux surface 64.

  19. Enhanced Lower Hybrid Current Drive Experiments on HT-7 Tokamak

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Effective Lower Hybrid Current Driving (LHCD) and improved confinement exper-iments in higher plasma parameters (Ip > 200 kA, ne> 2×1013 cm-3, Te ≥ 1 keⅤ) havebeen curried out in optimized LH wave spectrum and plasma parameters in HT-7 supercon-ducting tokamak. The dependence of current driving efficiency on LH power spectrum, plasmadensity ne and toroidal magnetic field BT has been obtained under optimal conditions. A goodCD efficiency was obtained at higher plasma current and higher electron density. The improve-ment of the energy confinement time is accompanied with the increase in line averaged electrondensity, and in ion and electron temperatures. The highest current driving efficiency reachedηCD = IpneR/PRF ≈ 1.05 × 1019 Am-2/W. Wave-plasma coupling was sustained in a good stateand the reflective coefficient was less than 5%. The experiments have also demonstrated the abilityof LH wave in the start-up and ramp-up of the plasma current. The measurement of the temporaldistribution of plasma parameter shows that lower hybrid leads to a broader profile in plasmaparameter. The LH power deposition profile and the plasma current density profile were modeledwith a 2D Fokker-Planck code corresponding to the evolution process of the hard x-ray detectorarray.

  20. Electric machine and current source inverter drive system

    Science.gov (United States)

    Hsu, John S

    2014-06-24

    A drive system includes an electric machine and a current source inverter (CSI). This integration of an electric machine and an inverter uses the machine's field excitation coil for not only flux generation in the machine but also for the CSI inductor. This integration of the two technologies, namely the U machine motor and the CSI, opens a new chapter for the component function integration instead of the traditional integration by simply placing separate machine and inverter components in the same housing. Elimination of the CSI inductor adds to the CSI volumetric reduction of the capacitors and the elimination of PMs for the motor further improve the drive system cost, weight, and volume.

  1. Current drive at plasma densities required for thermonuclear reactors.

    Science.gov (United States)

    Cesario, R; Amicucci, L; Cardinali, A; Castaldo, C; Marinucci, M; Panaccione, L; Santini, F; Tudisco, O; Apicella, M L; Calabrò, G; Cianfarani, C; Frigione, D; Galli, A; Mazzitelli, G; Mazzotta, C; Pericoli, V; Schettini, G; Tuccillo, A A

    2010-08-10

    Progress in thermonuclear fusion energy research based on deuterium plasmas magnetically confined in toroidal tokamak devices requires the development of efficient current drive methods. Previous experiments have shown that plasma current can be driven effectively by externally launched radio frequency power coupled to lower hybrid plasma waves. However, at the high plasma densities required for fusion power plants, the coupled radio frequency power does not penetrate into the plasma core, possibly because of strong wave interactions with the plasma edge. Here we show experiments performed on FTU (Frascati Tokamak Upgrade) based on theoretical predictions that nonlinear interactions diminish when the peripheral plasma electron temperature is high, allowing significant wave penetration at high density. The results show that the coupled radio frequency power can penetrate into high-density plasmas due to weaker plasma edge effects, thus extending the effective range of lower hybrid current drive towards the domain relevant for fusion reactors.

  2. Physics of electron cyclotron current drive on DIII-D

    CERN Document Server

    Petty, C C; Harvey, R W; Kinsey, J E; Lao, L L; Lohr, J; Luce, T C; Makowski, M A; Prater, R

    2002-01-01

    OAK A271 PHYSICS OF ELECTRON CYCLOTRON CURRENT DRIVE ON DIII-D. Recent experiments on the DIII-D tokamak have focused on determining the effect of trapped particles on the electron cyclotron current drive (ECCD) efficiency. The measured ECCD efficiency increases as the deposition location is moved towards the inboard midplane or towards smaller minor radius for both co and counter injection. The measured ECCD efficiency also increases with increasing electron density and/or temperature. The experimental ECCD is compared to both the linear theory (Toray-GA) as well as a quasilinear Fokker-Planck model (CQL3D). The experimental ECCD is found to be in better agreement with the more complete Fokker-Planck calculation, especially for cases of high rf power density and/or loop voltage. The narrow width of the measured ECCD profile is consistent with only low levels of radial transport for the current carrying electrons.

  3. Fast wave current drive antenna performance on D3-D

    Science.gov (United States)

    Mayberry, M. J.; Pinsker, R. I.; Petty, C. C.; Chiu, S. C.; Jackson, G. L.; Lippmann, S. I.; Prater, R.; Porkolab, M.

    1991-10-01

    Fast wave current drive (FWCD) experiments at 60 MHz are being performed on the D3-D tokamak for the first time in high electron temperature, high (beta) target plasmas. A four-element phased-array antenna is used to launch a directional wave spectrum with the peak n(sub parallel) value (approximately = 7) optimized for strong single-pass electron absorption due to electron Landau damping. For this experiment, high power FW injection (2 MW) must be accomplished without voltage breakdown in the transmission lines or antenna, and without significant impurity influx. In addition, there is the technological challenge of impedance matching a four-element antenna while maintaining equal currents and the correct phasing (90 degrees) in each of the straps for a directional spectrum. We describe the performance of the D3-D FWCD antenna during initial FW electron heating and current drive experiments in terms of these requirements.

  4. Fast Wave Current Drive Antenna Performance on DIII-D

    Science.gov (United States)

    Mayberry, M. J.; Pinsker, R. I.; Petty, C. C.; Chiu, S. C.; Jackson, G. L.; Lippmann, S. I.; Porkolab, M.; Prater, R.; Baity, F. W.; Goulding, R. H.; Hoffman, D. J.

    1992-01-01

    Fast wave current drive (FWCD) experiments at 60 MHz are being performed on the DIII-D tokamak for the first time in high electron temperature, high β target plasmas. A four-element phased-array antenna is used to launch a directional wave spectrum with the peak n∥ value (≂7) optimized for strong single-pass electron absorption due to electron Landau damping. For this experiment, high power FW injection (2 MW) must be accomplished without voltage breakdown in the transmission lines or antenna, and without significant impurity influx. In addition, there is the technological challenge of impedance matching a four-element antenna while maintaining equal currents and the correct phasing (90°) in each of the straps for a directional spectrum. In this paper we describe the performance of the DIII-D FWCD antenna during initial FW electron heating and current drive experiments in terms of these requirements.

  5. Direct calculation of current drive efficiency in FISIC code

    Energy Technology Data Exchange (ETDEWEB)

    Wright, J.C.; Phillips, C.K. [Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543-0451 (United States); Bonoli, P.T. [Plasma Fusion Center, MIT Cambridge, Massachusetts 02139 (United States)

    1996-02-01

    Two-dimensional RF modeling codes use a parameterization (1) of current drive efficiencies to calculate fast wave driven currents. This parameterization assumes a uniform quasi-linear diffusion coefficient and requires {ital a} {ital priori} knowledge of the wave polarizations. These difficulties may be avoided by a direct calculation of the quasilinear diffusion coefficient from the Kennel-Englemann form with the field polarizations calculated by the full wave code, FISIC (2). Current profiles are calculated using the adjoint formulation (3). Comparisons between the two formulations are presented. {copyright} {ital 1996 American Institute of Physics.}

  6. Direct calculation of current drive efficiency in FISIC code

    Science.gov (United States)

    Wright, J. C.; Phillips, C. K.; Bonoli, P. T.

    1996-02-01

    Two-dimensional RF modeling codes use a parameterization (1) of current drive efficiencies to calculate fast wave driven currents. This parameterization assumes a uniform quasi-linear diffusion coefficient and requires a priori knowledge of the wave polarizations. These difficulties may be avoided by a direct calculation of the quasilinear diffusion coefficient from the Kennel-Englemann form with the field polarizations calculated by the full wave code, FISIC (2). Current profiles are calculated using the adjoint formulation (3). Comparisons between the two formulations are presented.

  7. An Imposed Dynamo Current Drive Experiment: Demonstration of Confinement

    Science.gov (United States)

    Jarboe, Thomas; Hansen, Chris; Hossack, Aaron; Marklin, George; Morgan, Kyle; Nelson, Brian; Sutherland, Derek; Victor, Brian

    2014-10-01

    An experiment for studying and developing the efficient sustainment of a spheromak with sufficient confinement (current-drive power heats the plasma to its stability β-limit) and in the keV temperature range is discussed. A high- β spheromak sustained by imposed dynamo current drive (IDCD) is justified because: previous transient experiments showed sufficient confinement in the keV range with no external toroidal field coil; recent results on HIT-SI show sustainment with sufficient confinement at low temperature; the potential of IDCD of solving other fusion issues; a very attractive reactor concept; and the general need for efficient current drive in magnetic fusion. The design of a 0.55 m minor radius machine with the required density control, wall loading, and neutral shielding for a 2 s pulse is presented. Peak temperatures of 1 keV and toroidal currents of 1.35 MA and 16% wall-normalized plasma beta are envisioned. The experiment is large enough to address the key issues yet small enough for rapid modification and for extended MHD modeling of startup and code validation.

  8. Collisional current drive in two interpenetrating plasma jets

    Energy Technology Data Exchange (ETDEWEB)

    Ryutov, D. D.; Kugland, N. L.; Park, H.-S.; Pollaine, S. M.; Remington, B. A.; Ross, J. S. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States)

    2011-10-15

    The magnetic field generation in two interpenetrating, weakly collisional plasma streams produced by intense lasers is considered. The generation mechanism is very similar to the neutral beam injection current drive in toroidal fusion devices, with the differences related to the absence of the initial magnetic field, short interaction time, and different geometry. Spatial and temporal characteristics of the magnetic field produced in two counterstreaming jets are evaluated; it is shown that the magnetic field of order of 1 T can be generated for modest jet parameters. Conditions under which this mechanism dominates that of the ''Biermann battery'' are discussed. Other settings where the mechanism of the collisional current drive can be important for the generation of seed magnetic fields include astrophysics and interiors of hohlraums.

  9. Brushless DC motor Drive during Speed regulation with Current Controller

    Directory of Open Access Journals (Sweden)

    Bhikshalu Manchala

    2015-04-01

    Full Text Available Brushless DC Motor (BLDC is one of the best electrical drives that have increasing popularity, due to their high efficiency, reliability, good dynamic response and very low maintenance. Due to the increasing demand for compact & reliable motors and the evolution of low cost power semiconductor switches and permanent magnet (PM materials, brushless DC motors become popular in every application from home appliances to aerospace industry. The conventional techniques for controlling the stator phase current in a brushless DC drive are practically effective in low speed and cannot reduce the commutation torque ripple in high speed range. This paper presents the PI controller for speed control of BLDC motor. The output of the PI controllers is summed and is given as the input to the current controller. The BLDC motor is fed from the inverter where the rotor position and current controller is the input. The complete model of the proposed drive system is developed and simulated using MATLAB/Simulink software. The operation principle of using component is analysed and the simulation results are presented in this to verify the theoretical analysis.

  10. Towards fully non-inductive current drive operation in JET

    Energy Technology Data Exchange (ETDEWEB)

    Litaudon, X. [Association Euratom-CEA Cadarache, Dept. de Recherches sur la Fusion Controlee, 13 - Saint-Paul-lez-Durance (France); Crisanti, F. [Association Euratom-ENEA sulla Fusione, Centro Ricerche Frascati (Italy); Alper, B. [Euratom-UKAEA Fusion Association, Culham Science Centre, Abingdon, Oxon (United Kingdom)] [and others

    2002-01-01

    Quasi steady operation has been achieved at JET in the high confinement regime with Internal Transport Barriers, ITBs. The ITBs' performances are maintained up to 11 s. This duration, much larger than the energy confinement time, is already approaching a current resistive time. The high performance phase is limited only by plant constraints. The radial profiles of the thermal electron and ion pressures have steep gradients typically at mid-plasma radius. A large fraction of non-inductive current (above 80%) is sustained throughout the high performance phase with a poloidal beta exceeding unity. The safety factor profile plays an important role in sustaining the ITB characteristics. In this regime where the self-generated bootstrap current (up to LOMA) represents 50% of the total current, the resistive evolution of the non-monotonic q-profile is slowed down by using off-axis lower hybrid current drive. (authors)

  11. Path to Efficient Lower Hybrid Current Drive at High Density

    Science.gov (United States)

    Baek, S. G.; Bonoli, P. T.; Brunner, D.; Faust, I.; Labombard, B. L.; Parker, R. R.; Shiraiwa, S.; Wallace, G. M.; Wukitch, S.

    2015-11-01

    Recovery of lower hybrid current drive (LHCD) efficiency at high density was demonstrated on Alcator C-Mod by modifying the scrape-off layer (SOL) plasma. RF probe measurements around the C-Mod tokamak indicate that the LH wave amplitude at the high field side wall significantly attenuates with plasma density. This is interpreted as enhanced collisional loss due to the increase in the SOL density and width. By taking advantage of the narrower SOL width by doubling plasma current to 1.1 MA, it is found that the LH wave amplitude maintains its strength, and an effective current drive is extended to above 1x10e20 m-3. An order of magnitude increase in non-thermal Bremsstrahlung emission is consistent with ray-tracing results which take into account the change of SOL profiles with current. In the coming campaign, a further investigation on the role of the SOL plasma is planned by raising plasma current above 1.1 MA. This will be aided with newly developed RF magnetic loop antennas mounted on a radially movable probe head. This system is expected to intercept the LH resonance cone on the first pass, allowing us to measure radial profiles of both the wave amplitude and dominant parallel wavenumber in the SOL for the first time. These data will be compared with the GENRAY ray-tracing code. Work supported by USDoE awards DE-FC02-99ER54512.

  12. Direct Calculations of Current Drive with a Full Wave Code

    Science.gov (United States)

    Wright, John C.; Phillips, Cynthia K.

    1997-11-01

    We have developed a current drive package that evaluates the current driven by fast magnetosonic waves in arbitrary flux geometry. An expression for the quasilinear flux has been derived which accounts for coupling between modes in the spectrum of waves launched from the antenna. The field amplitudes are calculated in the full wave code, FISIC, and the current response function, \\chi, also known as the Spitzer function, is determined with Charles Karney's Fokker-Planck code, adj.f. Both codes have been modified to incorporate the same numerical equilibria. To model the effects of a trapped particle population, the bounce averaged equations for current and power are used, and the bounce averaged flux is calculated. The computer model is benchmarked against the homogenous equations for a high aspect ratio case in which the expected agreement is confirmed. Results from cases for TFTR, NSTX and CDX-U are contrasted with the predictions of the Ehst-Karney parameterization of current drive for circular equilibria. For theoretical background, please see the authors' archive of papers. (http://w3.pppl.gov/ ~jwright/Publications)

  13. Electric machine and current source inverter drive system

    Energy Technology Data Exchange (ETDEWEB)

    Hsu, John S

    2014-06-24

    A drive system includes an electric machine and a current source inverter (CSI). This integration of an electric machine and an inverter uses the machine's field excitation coil for not only flux generation in the machine but also for the CSI inductor. This integration of the two technologies, namely the U machine motor and the CSI, opens a new chapter for the component function integration instead of the traditional integration by simply placing separate machine and inverter components in the same housing. Elimination of the CSI inductor adds to the CSI volumetric reduction of the capacitors and the elimination of PMs for the motor further improve the drive system cost, weight, and volume.

  14. Modeling of finite aspect ratio effects on current drive

    Energy Technology Data Exchange (ETDEWEB)

    Wright, J.C.; Phillips, C.K. [Princeton Plasma Physics Lab., NJ (United States)

    1996-12-31

    Most 2D RF modeling codes use a parameterization of current drive efficiencies to calculate fast wave driven currents. This parameterization assumes a uniform diffusion coefficient and requires a priori knowledge of the wave polarizations. These difficulties may be avoided by a direct calculation of the quasilinear diffusion coefficient from the Kennel-Englemann form with the field polarizations calculated by a full wave code. This eliminates the need to use the approximation inherent in the parameterization. Current profiles are then calculated using the adjoint formulation. This approach has been implemented in the FISIC code. The accuracy of the parameterization of the current drive efficiency, {eta}, is judged by a comparison with a direct calculation: where {chi} is the adjoint function, {epsilon} is the kinetic energy, and {rvec {Gamma}} is the quasilinear flux. It is shown that for large aspect ratio devices ({epsilon} {r_arrow} 0), the parameterization is nearly identical to the direct calculation. As the aspect ratio approaches unity, visible differences between the two calculations appear.

  15. Current drive by electron cyclotron waves in stellarators

    Energy Technology Data Exchange (ETDEWEB)

    Castejon, F.; Alejaldre, C.; Coarasa, J. A.

    1992-07-01

    In this paper we propose a method to estimate the induced current by Electron Cyclotron waves fast enough, from the numerical point of view, to be included in a ray-tracing code, and yet accounting for the complicated geometry of stellarators. Since trapped particle effects are particularly important in this Current Drive method and in stellarator magnetic configuration, they are considered by the modification they introduce in the current drive efficiency. Basically, the method consists of integrating the Fisch and Boozer relativistic efficiency, corrected with the effect of trapped particles, times the absorbed power per momentum interval. This one is calculated for a Maxwellian distribution function, assuming a nearly linear regime. The influence of impurities and of species which are not protons is studied, calculating the efficiency for plasmas with Zeff) - Finally, a numerical analysis particularized to TJ-II stellarator is presented. The absorbed power density is calculated by the ray tracing code RAYS, taking into account the actual microwave beam structure. (Author) 23 refs.

  16. Current drive generation based on autoresonance and intermittent trapping mechanisms

    Energy Technology Data Exchange (ETDEWEB)

    Nakach, R. [Association Euratom-CEA, CEA/Cadarache, Dept. de Recherches sur la Fusion Controlee (DRFC), 13 - Saint-Paul-lez-Durance (France); Gell, Y. [CET, Tel-Aviv (Israel)

    1999-10-15

    Two mechanisms for generating streams of high parallel velocity of electrons are presented. One has its origin in Autoresonance (AR) interaction taking place after a trapping conditioning stage, the second being dominated by the trapping itself. These mechanisms are revealed from the study of the relativistic motion of an electron in a configuration consisting of two counterpropagating electromagnetic waves along a uniform magnetic field in a dispersive medium. The operation of these mechanisms was found to circumvent the deterioration of the electron acceleration process which is characteristic for a dispersive medium, allowing for an effective generation of current drive. (author)

  17. Fluid equations in the presence of electron cyclotron current drive

    Energy Technology Data Exchange (ETDEWEB)

    Jenkins, Thomas G.; Kruger, Scott E. [Tech-X Corporation, 5621 Arapahoe Avenue, Boulder, Colorado 80303 (United States)

    2012-12-15

    Two-fluid equations, which include the physics imparted by an externally applied radiofrequency source near electron cyclotron resonance, are derived in their extended magnetohydrodynamic forms using the formalism of Hegna and Callen [Phys. Plasmas 16, 112501 (2009)]. The equations are compatible with the closed fluid/drift-kinetic model developed by Ramos [Phys. Plasmas 17, 082502 (2010); 18, 102506 (2011)] for fusion-relevant regimes with low collisionality and slow dynamics, and they facilitate the development of advanced computational models for electron cyclotron current drive-induced suppression of neoclassical tearing modes.

  18. Current Capabilities of the Fuel Performance Modeling Code PARFUME

    Energy Technology Data Exchange (ETDEWEB)

    G. K. Miller; D. A. Petti; J. T. Maki; D. L. Knudson

    2004-09-01

    The success of gas reactors depends upon the safety and quality of the coated particle fuel. A fuel performance modeling code (called PARFUME), which simulates the mechanical and physico-chemical behavior of fuel particles during irradiation, is under development at the Idaho National Engineering and Environmental Laboratory. Among current capabilities in the code are: 1) various options for calculating CO production and fission product gas release, 2) a thermal model that calculates a time-dependent temperature profile through a pebble bed sphere or a prismatic block core, as well as through the layers of each analyzed particle, 3) simulation of multi-dimensional particle behavior associated with cracking in the IPyC layer, partial debonding of the IPyC from the SiC, particle asphericity, kernel migration, and thinning of the SiC caused by interaction of fission products with the SiC, 4) two independent methods for determining particle failure probabilities, 5) a model for calculating release-to-birth (R/B) ratios of gaseous fission products, that accounts for particle failures and uranium contamination in the fuel matrix, and 6) the evaluation of an accident condition, where a particle experiences a sudden change in temperature following a period of normal irradiation. This paper presents an overview of the code.

  19. Speed Control of Brushless Dc Motor Using Current Fed Quasi Z-source Inverter with Regeneration Capability

    Directory of Open Access Journals (Sweden)

    A. Santhi Mary Antony

    2015-06-01

    Full Text Available Current fed Quasi Z-Source Inverters (qZSI have the advantages of voltage buck-boost capability, improved reliability, reduced passive component ratings, continuous input current, a common dc rail between source and inverter and unique regeneration capability. This current-fed qZSIs are bidirectional with an additional diode, unlike the voltage-fed ZSI that needs a switch to achieve bidirectional power flow. Since current fed quasi Z Source Inverter has many advantages it can be employed for motor drive applications such as Brushless DC motor (BLDC drive. Therefore this study proposes the use of qZSI for BLDC motor. The simulation results for the same are presented in this study.

  20. Recent experimental results of KSTAR RF heating and current drive

    Energy Technology Data Exchange (ETDEWEB)

    Wang, S. J., E-mail: sjwang@nfri.re.kr; Kim, J.; Jeong, J. H.; Kim, H. J.; Joung, M.; Bae, Y. S.; Kwak, J. G. [National Fusion Research Institute, Daejoen, 305-806 (Korea, Republic of)

    2015-12-10

    The overview of KSTAR activities on ICRH, LHCD and ECH/CD including the last experimental results and future plan aiming for long-pulse high-beta plasma will be presented. Recently we achieved reasonable coupling of ICRF power to H-mode plasma through several efforts to increase system reliability. Power balance will be discussed on this experiment. LHCD is still struggling in the low power regime. Review of antenna spectrum for the higher coupling in H-mode plasma will be tried. ECH/CD provides 41 sec, 0.8 MW of heating power to support high-performance long-pulse discharge. Also, 170 GHz ECH system is integrated with the Plasma Control System (PCS) for the feedback controlling of NTM. Status and plan of ECH/CD will be discussed. Finally, helicon current drive is being prepared for the next stage of KSTAR operation. The hardware preparation and the calculation results of helicon current drive in KSTAR plasma will be discussed.

  1. The ESA River & Lake System: Current Capabilities and Future Potential

    DEFF Research Database (Denmark)

    Smith, Richard G.; Salloway, Mark; Berry, Philippa A. M.;

    Measuring the earth's river and lake resources using satellite radar altimetry offers a unique global monitoring capability, which complements the detailed measurements made by the steadily decreasing number of in-situ gauges. To exploit this unique remote monitoring capability, a global pilot sc...

  2. Development of an ultrasonic linear motor with ultra-positioning capability and four driving feet.

    Science.gov (United States)

    Zhu, Cong; Chu, Xiangcheng; Yuan, Songmei; Zhong, Zuojin; Zhao, Yanqiang; Gao, Shuning

    2016-12-01

    This paper presents a novel linear piezoelectric motor which is suitable for rapid ultra-precision positioning. The finite element analysis (FEA) was applied for optimal design and further analysis, then experiments were conducted to investigate its performance. By changing the input signal, the proposed motor was found capable of working in the fast driving mode as well as in the precision positioning mode. When working in the fast driving mode, the motor acts as an ultrasonic motor with maximum no-load speed up to 181.2mm/s and maximum thrust of 1.7N at 200Vp-p. Also, when working in precision positioning mode, the motor can be regarded as a flexible hinge piezoelectric actuator with arbitrary motion in the range of 8μm. The measurable minimum output displacement was found to be 0.08μm, but theoretically, can be even smaller. More importantly, the motor can be quickly and accurately positioned in a large stroke.

  3. Current drive generation based on autoresonance and intermittent trapping mechanisms

    Energy Technology Data Exchange (ETDEWEB)

    Nakach, R. [Association Euratom-CEA, CEA/Cadarache, Dept. de Recherches sur la Fusion Controlee (DRFC), 13 - Saint-Paul-lez-Durance (France); Gell, Y. [CET, Israel(Israel)

    1999-04-01

    Two mechanisms for generating stream of high velocity of electrons are presented. One has its origin in Auto Resonance interaction (AR) which takes place in the system after a trapping conditioning stage, the second being dominated by the trapping process itself. These mechanisms are revealed from the study of the relativistic motion of an electron in a configuration consisting of two counterpropagating electromagnetic waves along a constant magnetic field in a dispersive medium. Using a Hamiltonian formalism, we have numerically solved the equations of motion and presented the results in a set of figures showing the generation of stream of electrons having high parallel velocities. Insight into these numerical results is gained from a theoretical analysis which consists of a reformulation of the equations of motion. The operation of these mechanisms was found to circumvent the deterioration of the electron acceleration process which is characteristic for a dispersive medium, allowing for an effective generation of current drive. Discussion of the results follows. (author)

  4. Trapped electron effects on ICRF Current Drive Predictions in TFTR

    Science.gov (United States)

    Wright, John C.; Phillips, Cynthia K.; Bonoli, Paul T.

    1996-11-01

    Most 2D RF modeling codes use a parameterization^1 of current drive efficiencies to calculate fast wave driven currents. Because this parameterization is derived from a ray--tracing model, there are difficulties in applying it to a spectrum of waves. In addition, one cannot account for multiple resonances and coherency effects between the electrons and the waves. These difficulties may be avoided by a direct calculation of the quasilinear diffusion coefficient in an inhomogenous geometry coupled with a full wave code for the field polarizations. Current profiles are then calculated using the adjoint formulation^2, with the magnetic equilibrium specified consistently in both the adjoint routine and the full wave code. This approach has been implemented in the FISIC code^3. Results are benchmarked by comparing a power deposition calculation from conductivity to one from the quasilinear expression. It is shown that the two expressions agree. We quantify differences seen based upon aspect ratio and elongation. The largest discrepancies are seen in the regime of small aspect ratio, and little loss in accuracy for moderate aspect ratios ~>3. This work supported by DoE contract No. DE--AC02--76--CH03073. ^1 D. A. Ehst and C. F. F. Karney, Nucl. Fusion 31, 1933 (1991). ^2 C. F. F. Karney, Computer Physics Reports 4, 183 (1986). ^3 M. Brambilla and T. Krücken, Nucl. Fusion 28, 1813 (1988).

  5. Integrated Plasma Simulation of Lower Hybrid Current Drive in Tokamaks

    Science.gov (United States)

    Bonoli, P. T.; Wright, J. C.; Harvey, R. W.; Batchelor, D. B.; Berry, L. A.; Kessel, C. E.; Jardin, S. C.

    2012-03-01

    It has been shown in Alcator C-Mod that the onset time for sawteeth can be delayed significantly (up to 0.5 s) relative to ohmically heated plasmas, through the injection of off-axis LH current drive power [1]. We are simulating these experiments using the Integrated Plasma Simulator (IPS) [2], where the driven LH current density profiles are computed using a ray tracing component (GENRAY) and Fokker Planck code (CQL3D) [3] that are run in a tightly coupled time advance. The background plasma is evolved using the TSC transport code with the Porcelli sawtooth model [4]. Predictions of the driven LH current profiles will be compared with simpler ``reduced'' models for LHCD such as the LSC code which is implemented in TSC and which is also invoked within the IPS. [4pt] [1] C. E. Kessel et al, Bull. of the Am. Phys. Soc. 53, Poster PP6.00074 (2008). [0pt] [2] D. Batchelor et al, Journal of Physics: Conf. Series 125, 012039 (2008). [0pt] [3] R. W. Harvey and M. G. McCoy, Proc. of the IAEA Tech. Comm. Meeting on Simulation and Modeling of Therm. Plasmas, Montreal, Canada (1992). [0pt] [4] S. C. Jardin et al, J. Comp. Phys. 66, 481 (1986).

  6. Heating and Current Drive by Electron Cyclotron Waves

    Science.gov (United States)

    Prater, R.

    2003-10-01

    The physics model of electron cyclotron heating (ECH) and current drive (ECCD) is becoming well validated through systematic comparisons of theory and experiment. Work has shown that ECCD can be highly localized and robustly controlled, leading to applications including stabilization of MHD instabilities like neoclassical tearing modes, control and sustainment of desired profiles of current density and plasma pressure, and studies of localized transport. These physics applications and the study of the basic physics of ECH and ECCD were enabled by the advent of the gyrotron in the 1980s and of the diamond window for megawatt gyrotrons in the 1990s. The experimental work stimulated a broad base of theory based on first principles which is encapsulated in linear ray tracing codes and fully relativistic quasilinear Fokker-Planck codes. Recent experiments use measurements of the local poloidal magnetic field through the motional Stark effect to determine the magnitude and profile of the locally driven current. The subtle balance between wave-induced diffusion and Coulomb relaxation in velocity space provides an understanding of the effects of trapping of current-carrying electrons in the magnetic well, an effect which can be used to advantage. Strong quasilinear effects and radial transport of electrons which may broaden the driven current profile have also been observed under some conditions and appear to be consistent with theory, but in large devices these are usually insignificant. Additional advantages of ECH compared with other rf heating methods are that the antenna can be far removed from the plasma and the power density can be very high. The agreement of theory and experiment, the broad base of established applications, and the technical advantages of ECH support the application of ECH in next-step tokamaks and stellarators.

  7. Conditions for Lower Hybrid Current Drive in ITER

    Science.gov (United States)

    Cesario, R.; Amicucci, L.; Cardinali, A.; Castaldo, C.; Ceccuzzi, S.; Napoli, F.; Tuccillo, A. A.; Galli, A.; Schettini, G.

    2012-12-01

    To control the plasma current profile represents one of the most important problems of the research of nuclear fusion energy based on the tokamak concept, as in the plasma column the necessary conditions of stability and confinement should be satisfied. This problem can be solved by using the lower hybrid current drive (LHCD) effect, which was demonstrated to occur also at reactor grade high plasma densities provided that a proper method should be utilised, as assessed on FTU (Frascati Tokamak Upgrade). This method, based on theoretical predictions confirmed by experiment, produces relatively high electron temperature at the plasma periphery and scrape-off layer (SOL), consequently reducing the broadening of the spectrum launched by the antenna produced by parasitic wave physics of the edge, namely parametric instability (PI). The new results presented here show that, for kinetic profiles now foreseen for the SOL of ITER, PI is expected to hugely broaden the antenna spectrum and prevent any penetration in the core of the coupled LH power. However, considering the FTU method and assuming higher electron temperature at the edge (which would be however reasonable for ITER) the PI-produced spectral broadening would be mitigated, and enable the penetration of the coupled LH power in the main plasma. By successful LHCD effect, the control of the plasma current profile at normalised minor radius of about 0.8 would be possible, with much higher efficiency than that obtainable by other tools. A very useful reinforce of bootstrap current effects would be thus possible by LHCD in ITER.

  8. Current capability of a matured disposable acoustic sensor network

    Science.gov (United States)

    Beale, D. A. R.; Geddes, N. J., II; Hume, A.; Gray, A. J.

    2006-05-01

    In response to the needs of the UK MOD QinetiQ have designed, developed and trialled an ad-hoc, self organising network of acoustic nodes for in-depth deployment that can detect and track military targets in a range of environments and for all types of weapon locating. Research conducted has shown that disposable technologies are sufficiently mature to provide a useful military capability. Work this year has included a 3 month series of trials to exercise the prototype equipment and has provided an indication of in-service capability across a broad range of environments. This paper will discuss the scientific approach that was applied to the development of the equipment, from early laboratory development through to the prototype sensor network deployment in operationally representative environments. Highlights from the trials have been provided. New findings from the fusion of a low cost thermal imager that can be cued by the acoustic network are also discussed.

  9. Lower Hybrid Current Drive Experiments in Alcator C-Mod

    Energy Technology Data Exchange (ETDEWEB)

    J.R. Wilson, S. Bernabei, P. Bonoli, A. Hubbard, R. Parker, A. Schmidt, G. Wallace, J. Wright, and the Alcator C-Mod Team

    2007-10-09

    A Lower Hybrid Current Drive (LHCD) system has been installed on the Alcator C-MOD tokamak at MIT. Twelve klystrons at 4.6 GHz feed a 4x22 waveguide array. This system was designed for maximum flexibility in the launched parallel wave-number spectrum. This flexibility allows tailoring of the lower hybrid deposition under a variety of plasma conditions. Power levels up to 900 kW have been injected into the tokomak. The parallel wave number has been varied over a wide range, n|| ~ 1.6–4. Driven currents have been inferred from magnetic measurements by extrapolating to zero loop voltage and by direct comparison to Fisch-Karney theory, yielding an efficiency of n20IR/P ~ 0.3. Modeling using the CQL3D code supports these efficiencies. Sawtooth oscillations vanish, accompanied with peaking of the electron temperature (Te0 rises from 2.8 to 3.8 keV). Central q is inferred to rise above unity from the collapse of the sawtooth inversion radius, indicating off-axis cd as expected. Measurements of non-thermal x-ray and electron cyclotron emission confirm the presence of a significant fast electron population that varies with phase and plasma density. The x-ray emission is observed to be radialy broader than that predicted by simple ray tracing codes. Possible explanations for this broader emission include fast electron diffusion or broader deposition than simple ray tracing predictions (perhaps due to diffractive effects).

  10. Lower hybrid counter current drive for edge current density modification in DIII-D

    Energy Technology Data Exchange (ETDEWEB)

    Fenstermacher, M.E.; Nevins, W.M. [Lawrence Livermore National Lab., CA (US); Porkolab, M.; Bonoli, P.T. [Massachusetts Inst. of Technology, Cambridge, MA (US). Plasma Fusion Center; Harvey, R.W. [General Atomics, San Diego, CA (US)

    1993-07-01

    Each of the Advanced Tokamak operating modes in DIII-D is thought to have a distinctive current density profile. So far these modes have only been achieved transiently through experiments which ramp the plasma current and shape. Extension of these modes to steady state requires non-inductive current profile control, e.g. with lower hybrid current drive (LHCD). Calculations of LHCD have been done for DIII-D using the ACCOME and CQL3D codes, showing that counter driven current at the plasma edge can cancel some of the undesirable edge bootstrap current and potentially extend the VH-mode. Results are presented for scenarios using 2.45 GHz LH waves launched from both the midplane and off-axis ports. The sensitivity of the results to injected power, n{sub e} and T{sub e}, and launched wave spectrum is also shown.

  11. Recent progress on lower hybrid current drive and implications for ITER

    CERN Document Server

    Hillairet, Julien; Goniche, M; Achard, J; Armitano, A; Beckett, B; Belo, J; Berger-By, G; Corbel, E; Delpech, L; Decker, J; Dumont, R; Guilhem, D; Kazarian, F; Litaudon, X; Magne, R; Marfisi, L; Mollard, P; Namkung, W; Nilsson, E; Park, S; Peysson, Y; Preynas, M; Sharma, P K; Prou, M

    2015-01-01

    The sustainment of steady-state plasmas in tokamaks requires efficient current drive systems. Lower Hybrid Current Drive (LHCD) is currently the most efficient method to generate a continuous additional off-axis toroidal plasma current as well as reduce the poloidal flux consumption during the plasma current ramp-up phase. The operation of the Tore Supra ITER-like LH launcher has demonstrated the capability to couple LH power at ITER-like power densities with very low reflected power during long pulses. In addition, the installation of eight 700kW/CW klystrons at the LH transmitter has allowed increasing the total LH power in long pulse scenarios. However, in order to achieve pure stationary LH sustained plasmas, some R\\&D are needed to increase the reliability of all the systems and codes, from the RF sources to the plasma scenario prediction. The CEA/IRFM is addressing some of these issues by leading a R\\&D program towards an ITER LH system and by the validation of an integrated LH modeling suite of...

  12. Current drive generation based on autoresonance and intermittent trapping mechanisms.

    Science.gov (United States)

    Gell, Y; Nakach, R

    1999-09-01

    Two mechanisms for generating streams of high-velocity electrons are presented. One has its origin in auto resonance (AR) interaction, which takes place in the system after a trapping conditioning stage, the second being dominated by the trapping process itself. These mechanisms are revealed from the study of the relativistic motion of an electron in a configuration consisting of two counterpropagating electromagnetic waves along a constant magnetic field in a dispersive medium. Using a Hamiltonian formalism, we have numerically solved the equations of motion and presented the results in a set of figures showing the generation of streams of electrons having high parallel velocities. Insight into these numerical results is gained from a theoretical analysis, which consists of a reformulation of the equations of motion. The operation of these mechanisms was found to circumvent the deterioration of the electron acceleration process that is characteristic for a dispersive medium, thus allowing for an effective generation of a current drive. Discussion of the results follows.

  13. Current ramp-up with lower hybrid current drive in EAST

    Science.gov (United States)

    Ding, B. J.; Li, M. H.; Fisch, N. J.; Qin, H.; Li, J. G.; Wilson, J. R.; Kong, E. H.; Zhang, L.; Wei, W.; Li, Y. C.; Wang, M.; Xu, H. D.; Gong, X. Z.; Shen, B.; Liu, F. K.; Shan, J. F.

    2012-12-01

    More economical fusion reactors might be enabled through the cyclic operation of lower hybrid current drive. The first stage of cyclic operation would be to ramp up the plasma current with lower hybrid waves alone in low-density plasma. Such a current ramp-up was carried out successfully on the EAST tokamak. The plasma current was ramped up with a time-averaged rate of 18 kA/s with lower hybrid (LH) power. The average conversion efficiency Pel/PLH was about 3%. Over a transient phase, faster ramp-up was obtained. These experiments feature a separate measurement of the L/R time at the time of current ramp up.

  14. Current Behaviours and Attitudes Towards Texting While Driving in Australia

    DEFF Research Database (Denmark)

    Adamsen, Jannie Mia; Beasley, Keiran

    2011-01-01

    This paper aims to understand the behaviour of texting and driving among the broader driving public in Australia and uncover whether attitudes are congruent with behaviours. Recent studies have generally been focussing on the behaviours of 18-24 year olds suggesting that the practice is mainly...... confined to people in this age bracket. Findings from an anonymous online survey show that the practice of texting and driving is widespread in Australia and not just confined to the younger demographic. Additionally, evidence suggests smart phone users are more likely to engage in texting while driving....... The paper also reveals that a majority of people continue to text and drive despite having strong views on the dangers associated with the practice....

  15. Single-phase Multilevel Current Source Inverter with Reduced Device Count and Current Balancing Capability

    Directory of Open Access Journals (Sweden)

    MOALLEMI KHIAVI, A.

    2015-08-01

    Full Text Available Nowadays power converters play an important role in power system and industrial centers. One of the most important and widely used types of conversion is DC to AC conversion that is also called inverters. Generally inverters are divided to voltage source inverter (VSI and current source inverter (CSI. From another view the inverters are divided to two-level and multilevel types. The multilevel inverters are attractive because of their good output waveform quality. However, there has been less attention to multilevel current source inverter (MLCSI when compared with multilevel VSI. In this paper, a new topology for MLCSI is proposed. The proposed topology employs reduced number of switches to generate desired multilevel output current. The proposed MLCSI is capable of balancing the currents of the inductors that are used in the MLCSI structure. A multicarrier PWM based switching strategy is also proposed for the MLCSI. The simulation results using PSCAD/EMTDC as well as the experimental results from a single-phase 5-level CSI laboratory prototype demonstrate its validity.

  16. Electron cyclotron heating and current drive in toroidal geometry. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Kritz, A.H.

    1991-11-01

    The Principal Investigator has continued to work on problems associated both with the deposition and with the emission of electron cyclotron power in toroidal plasmas. We have investigated the use of electron cyclotron resonance heating for bringing compact tokamaks (BPX) to ignition-like parameters. This requires that we continue to refine the modeling capability of the TORCH code linked with the BALDUR 1 {1/2} D transport code. Using this computational tool, we have examined the dependence of ignition on heating and transport employing both theoretical (multi-mode) and empirically based transport models. The work on current drive focused on the suppression of tearing modes near the q = 2 surface and sawteeth near the q = 1 surface. Electron cyclotron current drive in CIT near the q =2 surface was evaluated for a launch scenario where electron cyclotron power was launched near the equatorial plane. The work on suppression of sawteeth has been oriented toward understanding the suppression that has been observed in a number of tokamaks, in particular, in the WT-3 tokamak in Kyoto. To evaluate the changes in current profile (shear) near the q =1 surface, simulations have been carried out using the linked BALDUR-TORCH code. We consider effects on shear resulting both from wave-induced current as well as from changes in conductivity associated with changes in local temperature. Abstracts and a paper relating to this work is included in Appendix A.

  17. A Modified Bridgeless Converter for SRM Drive with Reduced Ripple Current

    Directory of Open Access Journals (Sweden)

    Maheswari C krishnakumar

    2015-06-01

    Full Text Available Single Phase Switched Reluctance Motor is more popular in many industrial purposes for high speed applications because of its robust and rugged construction. For low cost and variable speed drive applications SRM are widely used.Due to doubly salient structure of motor, the torque pulsations are high when compared to other sinusoidal machines. The major drawback in using SRM drive is torque pulsations and increased number of switching components. In order to overcome these drawbacks, a bridgeless Single Ended Primary Inductor Converter (SEPIC is proposed. The major advantages of this converter are continuous output current,smaller voltage ripple and reduced semiconductor current stress when compared to the conventional SEPIC converter. The ripple free input current is obtained by using additional winding of input inductor and auxiliary capacitors. To achieve high efficiency, active power factor correction circuits (PFC are employed to precise the power factor. Further, the unity power factor can be obtained by making the input current during switching period proportional to the input voltage is proposed. The proposed system consists of reduced components and it is also capable of reducing the conduction losses. The working principles and the waveforms of proposed converter are analyzed. To analyze the circuit operation, theoretical analysis and simulation results are provided. Finally, the  comparison between the waveforms of conventional SEPIC and proposed system is presented by using MATLAB/Simulink tools.

  18. Advances in modeling of lower hybrid current drive

    Science.gov (United States)

    Peysson, Y.; Decker, J.; Nilsson, E.; Artaud, J.-F.; Ekedahl, A.; Goniche, M.; Hillairet, J.; Ding, B.; Li, M.; Bonoli, P. T.; Shiraiwa, S.; Madi, M.

    2016-04-01

    First principle modeling of the lower hybrid (LH) current drive in tokamak plasmas is a longstanding activity, which is gradually gaining in accuracy thanks to quantitative comparisons with experimental observations. The ability to reproduce simulatenously the plasma current and the non-thermal bremsstrahlung radial profiles in the hard x-ray (HXR) photon energy range represents in this context a significant achievement. Though subject to limitations, ray tracing calculations are commonly used for describing wave propagation in conjunction with Fokker-Planck codes, as it can capture prominent features of the LH wave dynamics in a tokamak plasma-like toroidal refraction. This tool has been validated on several machines when the full absorption of the LH wave requires the transfer of a small fraction of power from the main lobes of the launched power spectrum to a tail at a higher parallel refractive index. Conversely, standard modeling based on toroidal refraction only becomes more challenging when the spectral gap is large, except if other physical mechanisms may dominate to bridge it, like parametric instabilities, as suggested for JET LH discharges (Cesario et al 2004 Phys. Rev. Lett. 92 175002), or fast fluctuations of the launched power spectrum or ‘tail’ LH model, as shown for Tore Supra (Decker et al 2014 Phys. Plasma 21 092504). The applicability of the heuristic ‘tail’ LH model is investigated for a broader range of plasma parameters as compared to the Tore Supra study and with different LH wave characteristics. Discrepancies and agreements between simulations and experiments depending upon the different models used are discussed. The existence of a ‘tail’ in the launched power spectrum significantly improves the agreement between modeling and experiments in plasma conditions for which the spectral gap is large in EAST and Alcator C-Mod tokamaks. For the Alcator C-Mod tokamak, the experimental evolution of the HXR profiles with density suggests

  19. Lower hybrid current drive favoured by electron cyclotron radiofrequency heating

    Energy Technology Data Exchange (ETDEWEB)

    Cesario, R.; Cardinali, A.; Castaldo, C.; Marinucci, M.; Tuccillo, A. A. [Associazione EURATOM/ENEA sulla Fusione, Centro Ricerche Frascati, 00044, Frascati (Italy); Amicucci, L.; Galli, A. [Università di Roma Sapienza, Dipartimento Ingegneria Elettronica, Rome (Italy); Giruzzi, G. [CEA, IRFM, F-13108 Saint-Paul-lez-Durance (France); Napoli, F.; Schettini, G. [Università di Roma Tre, Dipartimento Ingegneria Elettronica, Rome (Italy)

    2014-02-12

    The important goal of adding to the bootstrap a fraction of non-inductive plasma current, which would be controlled for obtaining and optimizing steady-state profiles, can be reached by using the Current Drive produced by Lower Hybrid waves (LHCD). FTU (Frascati Tokamak Upgrade) experiments demonstrated, indeed, that LHCD is effective at reactor-graded high plasma density, and the LH spectral broadening is reduced, operating with higher electron temperature in the outer region of plasma column (T{sub e-periphery}). This method was obtained following the guidelines of theoretical predictions indicating that the broadening of launched spectrum produced by parametric instability (PI) should be reduced, and the LHCD effect at high density consequently enabled, under higher (T{sub e-periphery}). In FTU, the temperature increase in the outer plasma region was obtained by operating with reduced particle recycling, lithized walls and deep gas fuelling by means of fast pellet. Heating plasma periphery with electron cyclotron resonant waves (ECRH) will provide a further tool for achieving steady-state operations. New FTU experimental results are presented here, demonstrating that temperature effect at the plasma periphery, affecting LH penetration, occurs in a range of plasma parameters broader than in previous work. New information is also shown on the modelling assessing frequencies and growth rates of the PI coupled modes responsible of spectral broadening. Finally, we present the design of an experiment scheduled on FTU next campaign, where ECRH power is used to slightly increase the electron temperature in the outer plasma region of a high-density discharge aiming at restoring LHCD. Consequent to model results, by operating with a toroidal magnetic field of 6.3 T, useful for locating the electron cyclotron resonant layer at the periphery of the plasma column (r/a∼0.8, f{sub 0}=144 GHz), an increase of T{sub e} in the outer plasma (from 40 eV to 80 eV at r/a∼0.8) is

  20. Building Visual Artists’ Resilience Capabilities: Current Educator Strategies and Methods

    Directory of Open Access Journals (Sweden)

    Eileen Maree Siddins

    2016-07-01

    Full Text Available Enrolments in higher education programs in the creative and performing arts are increasing in many countries. Yet graduates of these degrees, who enter the broad sector known as the creative industries, face particular challenges in terms of securing long-term and sustainable employment. In addition, creative and performing artists face a range of mental challenges, caused by such factors as: the solitary nature of much creative practice, critical feedback by audiences and gatekeepers, or the general pressures associated with maintaining artistic relevance or integrity. The concepts of resilience and professional wellbeing are therefore highly relevant to those who pursue a career in creative industries, and while there has been an emerging body of work in this area, to date it has focussed on the performing arts area (e.g. music, theatre. Hence, in order to expand knowledge relevant to resilience and artists, this paper sets out to explore the extent to which current educators in the Australian context specifically address these issues within higher visual arts curricula; specifically the areas of illustration, design, film and photography. This was achieved via interviews with seventeen current academics working in these areas. The findings propose that higher education providers of programs in the visual arts consider placing a stronger emphasis on the embedded development of resilience and professional wellbeing capacities.

  1. Plasma Heating and Current Drive for Fusion Reactors

    Science.gov (United States)

    Holtkamp, Norbert

    2010-02-01

    ITER (in Latin ``the way'') is designed to demonstrate the scientific and technological feasibility of fusion energy. Fusion is the process by which two light atomic nuclei combine to form a heavier one and thus release energy. In the fusion process two isotopes of hydrogen - deuterium and tritium - fuse together to form a helium atom and a neutron. Thus fusion could provide large scale energy production without greenhouse effects; essentially limitless fuel would be available all over the world. The principal goals of ITER are to generate 500 megawatts of fusion power for periods of 300 to 500 seconds with a fusion power multiplication factor, Q, of at least 10. Q >= 10 (input power 50 MW / output power 500 MW). In a Tokamak the definition of the functionalities and requirements for the Plasma Heating and Current Drive are relevant in the determination of the overall plant efficiency, the operation cost of the plant and the plant availability. This paper summarise these functionalities and requirements in perspective of the systems under construction in ITER. It discusses the further steps necessary to meet those requirements. Approximately one half of the total heating will be provided by two Neutral Beam injection systems at with energy of 1 MeV and a beam power of 16 MW into the plasma. For ITER specific test facility is being build in order to develop and test the Neutral Beam injectors. Remote handling maintenance scheme for the NB systems, critical during the nuclear phase of the project, will be developed. In addition the paper will give an overview over the general status of ITER. )

  2. Current Capabilities and Development Potential in Surgical Robotics

    Directory of Open Access Journals (Sweden)

    Mathias Hoeckelmann

    2015-05-01

    Full Text Available Commercial surgical robots have been in clinical use since the mid-1990s, supporting surgeons in various tasks. In the past decades, many systems emerged as research platforms, and a few entered the global market. This paper summarizes the currently available surgical systems and research directions in the broader field of surgical robotics. The widely deployed teleoperated manipulators aim to enhance human cognitive and physical skills and provide smart tools for surgeons, while image-guided robotics focus on surpassing human limitations by introducing automated targeting and treatment delivery methods. Both concepts are discussed based on prototypes and commercial systems. Through concrete examples the possible future development paths of surgical robots are illustrated. While research efforts are taking different approaches to improve the capacity of such systems, the aim of this survey is to assess their maturity from the commercialization point of view.

  3. Effort of lower hybrid current drive experiments toward to H-mode in EAST

    Science.gov (United States)

    Ding, B. J.; Li, M. H.; Liu, F. K.; Shan, J. F.; Li, Y. C.; Wang, M.; Liu, L.; Zhao, L. M.; Yang, Y.; Wu, Z. G.; Feng, J. Q.; Hu, H. C.; Jia, H.; Cheng, M.; Zang, Q.; Lyu, B.; Duan, Y. M.; Lin, S. Y.; Wu, J. H.; Hillairet, J.; Ekedahl, A.; Peysson, Y.; Goniche, M.; Tuccillo, A. A.; Cesario, R.; Amicucci, L.; Shen, B.; Gong, X. Z.; Xu, G. S.; Zhao, H. L.; Hu, L. Q.; Li, J. G.; Wan, B. N.; EAST Team

    2017-02-01

    Lower hybrid current drive (LHCD) is an effective tool to achieve high confinement (H-mode) plasma in EAST. To utilize LHCD for accessing H-mode plasma, efforts have been made to improve LHW (lower hybrid wave)-plasma coupling and current drive capability at high density. Improved LHW-plasma coupling by means of local gas puffing and gas puffing from the electron side is routinely used during EAST operation with LHCD. High density experiments suggest that low recycling and high LH frequency are preferred for LHCD experiments at high density, consistent with previous results in other machines. The effect of LHCD on the current profile in EAST demonstrates that it is possible to control the plasma profile by optimizing the LHW spectrum. Repeatable H-mode plasma was obtained by LHCD and the maximum density during H-mode with the combination of 2.45 GHz and 4.6 GHz LH waves was up to 4.5  ×  1019 m-3.

  4. Air Quality Study Using Satellites - Current Capability and Future Plans

    Science.gov (United States)

    Bhartia, Pawan K.; Joiner, Joanna; Gleason, James; Liu, Xiong; Torres, Omar; Krotkov, Nickolay; Ziemke, Jerry; Chandra, Sushil

    2008-01-01

    Satellite instruments have had great success in monitoring the stratospheric ozone and in understanding the processes that control its daily to decadal scale variations. This field is now reaching its zenith with a number of satellite instruments from the US, Europe and Canada capping several decades of active research in this field. The primary public policy imperative of this research was to make reliable prediction of increases in biologically active surface UV radiation due to human activity. By contrast retrieval from satellite data of atmospheric constituents and photo-chemically active radiation that affect air quality is a new and growing field that is presenting us with unique challenges in measurement and data interpretation. A key distinction compared to stratospheric sensors is the greatly enhanced role of clouds, aerosols, and surfaces (CAS) in determining the quality and quantity of useful data that is available for air quality research. In our presentation we will use data from several sensors that are currently flying on the A-train satellite constellation, including OMI, MODIS, CLOUDSAT, and CALIPSO, to highlight that CAS can have both positive and negative effects on the information content of satellite measurements. This is in sharp contrast to other fields of remote sensing where CAS are usually considered an interference except in those cases when they are the primary subject of study. Our analysis has revealed that in the reflected wavelengths one often sees much further down into the atmosphere, through most cirrus, than one does in the emitted wavelengths. The lower level clouds provide a nice background against which one can track long-range transport of trace gases and aerosols. In addition, differences in trace gas columns estimated over cloudy and adjacent clear pixels can be used to measure boundary layer trace gases. However, in order to take full advantage of these features it will be necessary to greatly advance our understanding of

  5. The Use of Current Generators in Electrical Converter Drives for Stepper Motors

    Directory of Open Access Journals (Sweden)

    Emanoil Toma

    2014-09-01

    Full Text Available This paper presents some ways to realize electrical converters for stepper motor drives. The first part analyzes aspects for unipolar stepper motor and use of constant current generators. The second part present current sources based on peak limiting current trough the inductance of motor coil. A complete drive module for bipolar stepper motor was conceived and simulation results confirm their functionability.

  6. Broadband sidebands generated by parametric instability in lower hybrid current drive experiments on EAST

    Energy Technology Data Exchange (ETDEWEB)

    Amicucci, L., E-mail: luca.amicucci@enea.it; Castaldo, C.; Cesario, R.; Giovannozzi, E.; Tuccillo, A. A. [EUROfusion-ENEA, Centro Ricerche Frascati, Unità Fusione, Frascati (Italy); Ding, B. J.; Li, M. H. [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China)

    2015-12-10

    Modern research on nuclear fusion energy, based on the tokamak concept, has strong need of tools for actively driving non-inductive current especially at the periphery of plasma column, where tools available so far have poor efficiency. This is essential for solving one of the most critical problems for thermonuclear reactor, consisting in how to achieve the figure of fusion gain in the context of sufficient stability. The lower hybrid current drive (LHCD) effect has the potential capability of driving current at large radii of reactor plasma with high efficiency [1]. Experiments recently carried out on EAST showed that a strong activity of LH sideband waves (from the RF probe spectra), accompanied by weak core penetration of the coupled LH power, is present when operating at relatively high plasma densities. Previous theoretical results, confirmed by experiments on FTU, showed that the LH sideband phenomenon is produced by parametric instability (PI), which are mitigated by higher plasma edge temperatures. This condition is thus useful for enabling the LH power propagation when operating with profiles having high plasma densities even at the edge. In the present work, we show new PI modeling of EAST plasmas data, obtained in condition of higher plasma edge temperature due to chamber lithisation. The obtained trend of the PI frequencies and growth rates is consistent with data of RF probe spectra, available in different regimes of lithisated and not lithisated vessel. Moreover, these spectra are interpreted as PI effect occurring at the periphery of plasma column, however in the low field side where the LH power is coupled.

  7. Broadband sidebands generated by parametric instability in lower hybrid current drive experiments on EAST

    Science.gov (United States)

    Amicucci, L.; Ding, B. J.; Castaldo, C.; Cesario, R.; Giovannozzi, E.; Li, M. H.; Tuccillo, A. A.

    2015-12-01

    Modern research on nuclear fusion energy, based on the tokamak concept, has strong need of tools for actively driving non-inductive current especially at the periphery of plasma column, where tools available so far have poor efficiency. This is essential for solving one of the most critical problems for thermonuclear reactor, consisting in how to achieve the figure of fusion gain in the context of sufficient stability. The lower hybrid current drive (LHCD) effect has the potential capability of driving current at large radii of reactor plasma with high efficiency [1]. Experiments recently carried out on EAST showed that a strong activity of LH sideband waves (from the RF probe spectra), accompanied by weak core penetration of the coupled LH power, is present when operating at relatively high plasma densities. Previous theoretical results, confirmed by experiments on FTU, showed that the LH sideband phenomenon is produced by parametric instability (PI), which are mitigated by higher plasma edge temperatures. This condition is thus useful for enabling the LH power propagation when operating with profiles having high plasma densities even at the edge. In the present work, we show new PI modeling of EAST plasmas data, obtained in condition of higher plasma edge temperature due to chamber lithisation. The obtained trend of the PI frequencies and growth rates is consistent with data of RF probe spectra, available in different regimes of lithisated and not lithisated vessel. Moreover, these spectra are interpreted as PI effect occurring at the periphery of plasma column, however in the low field side where the LH power is coupled.

  8. Modeling of the influences of multiple modulated electron cyclotron current drive on NTMs in rotating plasma

    Science.gov (United States)

    Long, Chen; Jinyuan, Liu; Ping, Duan; Guangrui, Liu; Xingyu, Bian

    2017-02-01

    In this work, physical models of neoclassical tearing modes (NTMs) including bootstrap current and multiple modulated electron cyclotron current drive model are applied. Based on the specific physical problems during the suppression of NTMs by driven current, this work compares the efficiency of continuous and modulated driven currents, and simulates the physical processes of multiple modulated driven currents on suppressing rotating magnetic island. It is found that when island rotates along the poloidal direction, the suppression ability of continuous driven current can be massively reduced due to current deposition outside the island separatrix and reverse deposition direction at the X point, which can be avoided by current drive modulation. Multiple current drive has a better suppressing effect than single current drive. This work gives realistic numerical simulations by optimizing the model and parameters based on the experiments, which could provide references for successful suppression of NTMs in future advanced tokamak such as international thermonuclear experimental reactor.

  9. Brushless DC motor Drive during Speed regulation with Current Controller

    OpenAIRE

    Bhikshalu Manchala; T.Amar Kiran

    2015-01-01

    Brushless DC Motor (BLDC) is one of the best electrical drives that have increasing popularity, due to their high efficiency, reliability, good dynamic response and very low maintenance. Due to the increasing demand for compact & reliable motors and the evolution of low cost power semiconductor switches and permanent magnet (PM) materials, brushless DC motors become popular in every application from home appliances to aerospace industry. The conventional techniques for controlling...

  10. Research on Predicting Drive Current of Shipborne Satcom Antenna

    OpenAIRE

    Kong Jinping; Xu Zhengfeng; Wu Botao

    2015-01-01

    Predicting the effect of antenna wind load on servo system precisely is meaningful to ensure the safety of satcom antenna on operation, which can avoid overload operation. In this paper, the computational fluid dynamics is used to proceed numerical computation on the pressure distribution of the reflector and torque of drive shaft under different wind speed, windward angle and angle of pitch of the antenna. The simulation model is built under MATLAB/Simulink simulation environment, and the dr...

  11. An Improved Variable-Frequency Drive Based on Current Tracking

    Directory of Open Access Journals (Sweden)

    Zhiwei He

    2013-11-01

    Full Text Available Variable frequency devices are widely used in many power systems. A current tracking based VFD is proposed in this paper. The output current is firstly fed back and compared with a standard sine wave, the difference of them is then used for a PI regulator to control the PWM signal, so as to change the output current accordingly to make it approach the standard sine wave. Simulation and experiments results show that the current tracking VFD not only has a fast dynamic response, high current tracking precision, current limiting ability, but also has small distortion of the output sine wave current and low loss of the motor.    

  12. The role of the plasma current in turbulence decrease during lower hybrid current drive

    Science.gov (United States)

    Antar, G.; Ekedahl, A.; Goniche, M.; Asghar, A.; Žàček, F.

    2017-03-01

    The interaction of radio frequency (RF) waves with edge turbulence has resurfaced after the results obtained on many tokamaks showing that edge turbulence decreases when the ion cyclotron frequency heating (ICRH) is switched on. Using the lower hybrid (LH) waves to drive current into tokamak plasmas, this issue presented contradicting results with some tokamaks (FTU & HT-7) showing a net decrease, similar to the ICRH results, and others (Tore Supra) did not. In this article, these apparent discrepancies among tokamaks and RF wave frequencies are removed. It is found that turbulence large-scale structures in the scrape-off layer decrease at high enough plasma currents (Ip) on the Tore Supra tokamak. We distinguish three regimes: At low Ip's, no modification is detected with statistical properties of turbulence similar to ohmic plasmas even with PLH reaching 4.8 MW. At moderate plasma currents, turbulence properties are modified only at a high LH power. At high plasma currents, turbulent large scales are reduced to values smaller than 1 cm, and this is accompanied by a net decrease in the level of turbulence of about 30% even with a moderate LH power.

  13. Short term Braking Capability during Power Interruptions for Integrated Matrix Converter-Motor Drives

    DEFF Research Database (Denmark)

    Klumpner, Christian; Blaabjerg, Frede

    2002-01-01

    The new trend in Adjustable Speed Drives (ASD) is to integrate the inverter and the motor into a single unit in order to reduce the production cost, the commissioning time and the physical size of the equipment. This last issue becomes more important, making the matrix converter topology more...

  14. Improvements on Pulsed Current Sharing in Driving Parallel MOSFETs

    Science.gov (United States)

    Takagi, Hajime; Orihara, Masato; Yamada, Tsutomu; Yanagidaira, Takeshi

    To switch high-voltage and high-current pulses by using MOS (Metal Oxide Semiconductor) transistors, it is necessary to distribute evenly the voltage and current to each element connected in series and parallel. In parallel connection, the current flowing in each element is different depending on the series resistance and wiring inductance. We verified improvements on pulsed current sharing in parallel transistors which were arranged in line on a printed circuit board. Although Gate and Drain wirings are different in length, pulsed current was evenly distributed by using transmission line transformers. Dissipation in transistors were equalized and four transistors were driven simultaneously near the rated current.

  15. Clipper for High-Impedance Current-Drive Line

    Science.gov (United States)

    Woodhouse, Christopher E.

    1987-01-01

    New circuit leakage reduced by shunting current through saturated input at operational-amplifier follower already part of Howland, or equivalent, current source. Typical application is in circuit of germanium resistance thermometer in cryogenic system.

  16. Motion Control of a Four-wheel-drive Omnidirectional Wheelchair with High Step Climbing Capability

    OpenAIRE

    WADA, Masayoshi

    2010-01-01

    Mechanism and omnidirectional control of a 4WD mechanism for wheelchairs are presented in this chapter. The omnidirectional wheelchair system is proposed for improving maneuverability of standard wheelchairs The 4WD mechanism has high mobility which equips four wheels, two omni-wheels in the front and two normal tires in the rear, and all wheels provide traction even with two motors to drive these wheels. To realize holonomic and omnidirectional motion of a chair by utilizing the 4WD mechanis...

  17. Dynamic behavioral fingerprinting': What drives the deployment of environmental information and communication capabilities?

    NARCIS (Netherlands)

    Bremmers, H.J.; Haverkamp, D.J.; Omta, S.W.F.

    2009-01-01

    This article investigates the impact of organizational drivers for the implementation of business process and network information and communication capabilities (ICCs) supporting cleaner production in the Dutch food and beverage industry. We do so with the intention to promote `dynamic behavioral fi

  18. Detection and sizing of defects in control rod drive mechanism penetrations using eddy current and ultrasonics

    Energy Technology Data Exchange (ETDEWEB)

    Light, G.M.; Fisher, J.L.; Tennis, R.F.; Stolte, J.S.; Hendrix, G.J. [Southwest Research Inst., San Antonio, TX (United States)

    1996-08-01

    Over the last two years, concern has been generated about the capabilities of performing nondestructive evaluation (NDE) of the closure-head penetrations in nuclear-reactor pressure vessels. These penetrations are primarily for instrumentation and control rod drive mechanisms (CRDMs) and are usually thick-walled Inconel tubes, which are shrink-fitted into the steel closure head. The penetrations are then welded between the outside surface of the penetration and the inside surface of the closure head. Stress corrosion cracks initiating at the inner surface of the penetration have been reported at several plants. Through-wall cracks in the CRDM penetration or CRDM weld could lead to loss of coolant in the reactor vessel. The CRDM penetration presents a complex inspection geometry for conventional NDE techniques. A thermal sleeve, through which pass the mechanical linkages for operating the control rods, is inserted into the penetration in such a way that only a small annulus (nominally 3 mm) exists between the thermal sleeve and inside surface of the penetration. Ultrasonic (UT) and eddy current testing (ET) techniques that could be used to provide defect detection and sizing capability were investigated. This paper describes the ET and UT techniques, the probes developed, and the results obtained using these probes and techniques on CRDM penetration mock-ups.

  19. Estimating Heat and Mass Transfer Processes in Green Roof Systems: Current Modeling Capabilities and Limitations (Presentation)

    Energy Technology Data Exchange (ETDEWEB)

    Tabares Velasco, P. C.

    2011-04-01

    This presentation discusses estimating heat and mass transfer processes in green roof systems: current modeling capabilities and limitations. Green roofs are 'specialized roofing systems that support vegetation growth on rooftops.'

  20. What drives successful implementation of pollution prevention and cleaner technology strategy? The role of innovative capability.

    Science.gov (United States)

    Bhupendra, Kumar Verma; Sangle, Shirish

    2015-05-15

    Firms that are dynamic and prepared to implement environmental strategies have a potential competitive advantage over their industry counterparts. Therefore, it is important to understand, what capabilities are required to implement proactive environmental strategies. The paper discusses the attributes of innovative capability required by firms in order to adopt pollution prevention and cleaner technology strategies. Empirical results show that process and behavioral innovativeness are required by firms to implement a pollution prevention strategy. In addition to process and behavioral innovativeness, firms need a top management with high risk-taking ability as well as market, product, and strategic innovativeness to implement a cleaner technology strategy. The paper proposes some important managerial implications on the basis of the above research findings. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. Adiabatic Compression of Compact Tori for Current Drive and Heating

    Science.gov (United States)

    Woodruff, Simon; McNab, Angus; Miller, Kenneth; Ziemba, Tim

    2008-11-01

    Several critical issues stand in the development path for compact tori. An important one is the production of strong magnetic fields, (or large flux amplifications) by use of a low current source. The Pulsed Build-up Experiment is a Phase II SBIR project in which we aim to show a new means for generating strong magnetic fields from a low current source, namely, the repetitive injection of helicity-bearing plasma that also undergoes an acceleration and compression. In the Phase I SBIR, advanced computations were benchmarked against analytic theory and run to determine the best means for the acceleration and compression of a compact torus plasma. The study included detailed simulations of magnetic reconnection. In Phase II, an experiment has been designed and is being built to produce strong magnetic fields in a spheromak by the repetitive injection of magnetic helicity from a low current coaxial plasma source. The plasma will be accelerated and compressed in a similar manner to a traveling wave adiabatic compression scheme that was previously applied to a mirror plasma [1]. [1] P. M. Bellan Scalings for a Traveling Mirror Adiabatic Magnetic Compressor Rev. Sci. Instrum. 53(8) 1214 (1982) Work supported by DOE Grant No. DE-FG02-06ER84449.

  2. Assessment of Electron-Cyclotron-Current-Drive-Assisted Operation in DEMO

    Directory of Open Access Journals (Sweden)

    Marushchenko N.B.

    2012-09-01

    Full Text Available The achievable efficiency for external current drive through electron-cyclotron (EC waves in a demonstration tokamak reactor is discussed. Two possible reactor designs, one for steady state and one for pulsed operation, are considered. It is found that for midplane injection the achievable current drive efficiency is limited by secondharmonic absorption at levels consistent with previous studies. Propagation through the second-harmonic region can be reduced by moving the launch position to the high-field side (this can be obtained by injecting the beam from an upper port in the vacuum vessel. In this case, beam tracing calculations deliver values for the EC current drive efficiency approaching those usually reported for neutral beam current drive.

  3. Fast wave current drive modeling using the combined RANT3D and PICES codes

    Energy Technology Data Exchange (ETDEWEB)

    Jaeger, E.F.; Murakami, M.; Stallings, D.C. [and others

    1995-07-01

    Two numerical codes are combined to give a theoretical estimate of the current drive and direct electron heating by fast waves launched from phased antenna arrays on the DIII-D tokamak. Results are compared with experiment.

  4. Fast wave current drive modeling using the combined RANT3D and PICES Codes

    Science.gov (United States)

    Jaeger, E. F.; Murakami, M.; Stallings, D. C.; Carter, M. D.; Wang, C. Y.; Galambos, J. D.; Batchelor, D. B.; Baity, F. W.; Bell, G. L.; Wilgen, J. B.; Chiu, S. C.; DeGrassie, J. S.; Forest, C. B.; Kupfer, K.; Petty, C. C.; Pinsker, R. T.; Prater, R.; Lohr, J.; Lee, K. M.

    1996-02-01

    Two numerical codes are combined to give a theoretical estimate of the current drive and direct electron heating by fast waves launched from phased antenna arrays on the DIII-D tokamak. Results are compared with experiment.

  5. Coupling of α-channeling to |k∥| upshift in lower hybrid current drive

    Energy Technology Data Exchange (ETDEWEB)

    Ochs, I. E. [Harvard University, Cambridge, MA (United States). Department of Physics.; Bertelli, N. [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Fisch, N. J. [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)

    2014-08-26

    Although lower hybrid waves have been shown to be effective in driving plasma current in present-day tokamaks, they are predicted to strongly interact with the energetic α particles born from fusion reactions in eventual tokamak reactors.

  6. Experimental Research of Harmonic Spectrum of Currents at Traction Drive with PMSM

    Directory of Open Access Journals (Sweden)

    J. Novak

    2011-06-01

    Full Text Available The paper deals with the significant results of the experimental research of current harmonic spectrum of traction drive with permanent magnet synchronous motor. The experiments were done on a special workplace with a real traction drive for wheel vehicles. Current harmonic spectrum was analyzed by a specialized device on the base of central measuring station. The knowledge of current marked subharmonic components of stator winding is the most significant finding of experiments. The frequencies of these components are given by multiples of frequency of mechanical speeds. The subharmonic components also pass to input DC current of drive. This fact is important in particular from the point of view of legislative requirements to electromagnetic compatibility of drive with railway interlocking devices.

  7. High power millimeter wave experiment of ITER relevant electron cyclotron heating and current drive system.

    Science.gov (United States)

    Takahashi, K; Kajiwara, K; Oda, Y; Kasugai, A; Kobayashi, N; Sakamoto, K; Doane, J; Olstad, R; Henderson, M

    2011-06-01

    High power, long pulse millimeter (mm) wave experiments of the RF test stand (RFTS) of Japan Atomic Energy Agency (JAEA) were performed. The system consists of a 1 MW/170 GHz gyrotron, a long and short distance transmission line (TL), and an equatorial launcher (EL) mock-up. The RFTS has an ITER-relevant configuration, i.e., consisted by a 1 MW-170 GHz gyrotron, a mm wave TL, and an EL mock-up. The TL is composed of a matching optics unit, evacuated circular corrugated waveguides, 6-miter bends, an in-line waveguide switch, and an isolation valve. The EL-mock-up is fabricated according to the current design of the ITER launcher. The Gaussian-like beam radiation with the steering capability of 20°-40° from the EL mock-up was also successfully proved. The high power, long pulse power transmission test was conducted with the metallic load replaced by the EL mock-up, and the transmission of 1 MW/800 s and 0.5 MW/1000 s was successfully demonstrated with no arcing and no damages. The transmission efficiency of the TL was 96%. The results prove the feasibility of the ITER electron cyclotron heating and current drive system.

  8. A relativistic model of electron cyclotron current drive efficiency in tokamak plasmas

    OpenAIRE

    Lin-Liu Y.R.; Hu Y.J.; Hu Y.M.

    2012-01-01

    A fully relativistic model of electron cyclotron current drive (ECCD) efficiency based on the adjoint function techniques is considered. Numerical calculations of the current drive efficiency in a tokamak by using the variational approach are performed. A fully relativistic extension of the variational principle with the modified basis functions for the Spitzer function with momentum conservation in the electron-electron collision is described in general tokamak geometry. The model developed ...

  9. RF current drive by electron cyclotron waves in the presence of magnetic islands

    Energy Technology Data Exchange (ETDEWEB)

    Da Silva Rosa, P.; Giruzzi, G

    1999-11-01

    The influence of the presence of magnetic islands, and the consequent modification of the tokamak magnetic surface topology, on electron current drive is analyzed. To this end, a new 3D Fokker-Planck code has been developed, taking into account the modifications of the magnetic equilibrium topology owing to the presence of the islands. Significant differences between electron cyclotron current drive efficiency with and without island inside the plasma are found, particularly in the case of interaction with locked modes. (authors)

  10. Mass of a skyrmion under a driving current

    Science.gov (United States)

    Martinez, J. C.; Jalil, M. B. A.

    2017-02-01

    We present arguments for a mass term in the Landau-Lifshitz-Gilbert equation based on the notion of mass as an inertial quantity. From trajectories of skyrmions in a confining potential and a 1-D potential we see evidence for a mass-inertia connection. We derive an expression for the effective mass for skyrmions, 1.6 ε ×10-23 kg , where ε accounts for the mismatch between the local magnetic moment induced on the conduction electrons and its corresponding effect on the current-driven skyrmion and varies from 10-2 to 1.

  11. Current Research Activities in Drive System Technology in Support of the NASA Rotorcraft Program

    Science.gov (United States)

    Handschuh, Robert F.; Zakrajsek, James J.

    2006-01-01

    Drive system technology is a key area for improving rotorcraft performance, noise/vibration reduction, and reducing operational and manufacturing costs. An overview of current research areas that support the NASA Rotorcraft Program will be provided. Work in drive system technology is mainly focused within three research areas: advanced components, thermal behavior/emergency lubrication system operation, and diagnostics/prognostics (also known as Health and Usage Monitoring Systems (HUMS)). Current research activities in each of these activities will be presented. Also, an overview of the conceptual drive system requirements and possible arrangements for the Heavy Lift Rotorcraft program will be reviewed.

  12. Effects of passive components on the input current interharmonics of adjustable-speed drives

    DEFF Research Database (Denmark)

    Soltani, Hamid; Blaabjerg, Frede; Zare, Firuz;

    2016-01-01

    speed drives with and/or without motor current imbalance. The investigation is done at different motor operating frequencies and load torque values. It shows that selecting the small filter components (ac choke, dc choke and dc-link capacitor) results in different performances in respect to those......Current and voltage source Adjustable Speed Drives (ASDs) exert distortion current into the grid, which may produce some interharmonic components other than the characteristic harmonic components. This paper studies the effects of passive components on the input current interharmonics of adjustable...... interharmincs issued by motor current imbalance and other non-characteristic interharmonics. The results are helpful for engineers investigating the effects of drive filters on the input current interharmonic components....

  13. Lower hybrid current drive for edge current density modification in DIII-D: Final status report

    Energy Technology Data Exchange (ETDEWEB)

    Fenstermacher, M.E. [Lawrence Livermore National Lab., CA (United States); Porkolab, M. [Massachusetts Inst. of Tech., Cambridge, MA (United States). Plasma Fusion Center

    1993-08-04

    Application of Lower Hybrid (LH) Current Drive (CD) in the DIII-D tokamak has been studied at LLNL, off and on, for several years. The latest effort began in February 1992 in response to a letter from ASDEX indicating that the 2.45 GHz, 3 MW system there was available to be used on another device. An initial assessment of the possible uses for such a system on DIII-D was made and documented in September 1992. Multiple meetings with GA personnel and members of the LH community nationwide have occurred since that time. The work continued through the submission of the 1995 Field Work Proposals in March 1993 and was then put on hold due to budget limitations. The purpose of this document is to record the status of the work in such a way that it could fairly easily be restarted at a future date. This document will take the form of a collection of Appendices giving both background and the latest results from the FY 1993 work, connected by brief descriptive text. Section 2 will describe the final workshop on LHCD in DIII-D held at GA in February 1993. This was an open meeting with attendees from GA, LLNL, MIT and PPPL. Summary documents from the meeting and subsequent papers describing the results will be included in Appendices. Section 3 will describe the status of work on the use of low frequency (2.45 GHZ) LH power and Parametric Decay Instabilities (PDI) for the special case of high dielectric in the edge regions of the DIII-D plasma. This was one of the critical issues identified at the workshop. Other potential issues for LHCD in the DIII-D scenarios are: (1) damping of the waves on fast ions from neutral beam injection, (2) runaway electrons in the low density edge plasma, (3) the validity of the WKB approximation used in the ray-tracing models in the steep edge density gradients.

  14. The drive to strive: goal generation based on current needs

    Directory of Open Access Journals (Sweden)

    Elisabeth A Murray

    2013-06-01

    Full Text Available Hungry animals are influenced by a multitude of different factors when foraging for sustenance. Much of the work on animal foraging has focused on factors relating to the amount of time and energy animals expend searching for and harvesting foods. Models that emphasize such factors have been invaluable in determining when it is beneficial for an animal to search for pastures new. When foraging, however, animals also have to determine how to direct their search. For what food should they forage? There is no point searching for more of a particular food when you are sated from eating it. Here we review work in macaques and humans that has sought to reveal the neural circuits critical for determining the subjective value of different foods and associated objects in our environment and tracking this value over time. There is mounting evidence that a network composed of the orbitofrontal cortex (OFC, amygdala and medial thalamus is critical for linking objects in the environment with food value and adjusting those valuations in real time based on current biological needs. Temporal inactivation studies have revealed that the amygdala and OFC play distinct, but complementary roles in this valuation process. Such a network for determining the subjective value of different foods and, by extension, associated objects, must interact with systems that determine where and for how long to forage. Only by efficiently incorporating these two factors into their decisions will animals be able to achieve maximal fitness.

  15. GENERATING OF OPTIMAL QUANTIZATION LEVELS OF CONTROL CURRENTS FOR LINEAR STEPPING DRIVES OF PRECISION MOTION SYSTEMS

    Directory of Open Access Journals (Sweden)

    I. V. Dainiak

    2014-01-01

    Full Text Available The paper proposes a method of taking into account accumulated and temperature errors while forming coordinate discrete grid of a linear stepping drive. An algorithm for determination of optimal quantization levels of control currents of drive's phases has been developed in the paper; it minimizes an error of positioning that forms correction files for application of a control system in the software. Investigations on stability of discrete grid nodes coordinates have been carried our with the help of a monitoring station for accurate parameters of linear stepping drive. The investigations have proved an efficiency of the proposed algorithm and methodology for forming coordinate discrete grid.

  16. Fokker-Planck Simulation of Fast Wave Current Drive and Heating in the Reversed Field Pinch

    Science.gov (United States)

    Uchimoto, E.; Shiina, S.; Harvey, R. W.; Smirnov, A. P.; Forest, C. B.; Prager, S. C.; Wright, J. C.

    1999-11-01

    Fast wave current drive (FWCD) has been shown theoretically to be a good candidate for improving plasma confinement characteristics of a high-beta, reactor-grade RFP via current profile control.footnote S. Shiina, Y. Kondoh, H. Ishii, Nuclear Fusion 34, 1473 (1994); T. Nagai et al., Proc. ICPP (Nagoya, 1996), p. 1042; K. Kusano et al., 17th IAEA Fusion Energy Conf. (Yokohama, 1998), paper THP1/12. To assess the effects of toroidicity and quasilinear modifications to the electron distribution function on FWCD, we are using the RFP version of ray-tracing and Fokker-Planck codes (GENRAY and CQL3D). Although lower hybrid slow waves are ideally suited for poloidal current drive in large RFPs presently in operation, possible use of fast waves is being considered for core current drive and heating in these devices. For MST parameters, our calculations focus on intermediate to high harmonic fast waves for which geometric optics is valid.

  17. Closure of the single fluid magnetohydrodynamic equations in presence of electron cyclotron current drive

    NARCIS (Netherlands)

    Westerhof, E.; Pratt, J.

    2014-01-01

    In the presence of electron cyclotron current drive (ECCD), the Ohm's law of single fluid magnetohydrodynamics is modified as E + v × B = η(J – J EC). This paper presents a new closure relation for the EC driven current density appearing in this modified Ohm's law. The new relation faithfu

  18. The effect of toroidal field on the rotating magnetic field current drive in rotamak plasmas

    Institute of Scientific and Technical Information of China (English)

    Zhong Fang-Chuan; Huang Tian-Sen; Petrov Yuri

    2007-01-01

    A rotamak is one kind of compact spherically shaped magnetic-confinement device. In a rotamak the plasma current is driven by means of rotating magnetic field (RMF). The driven current can reverse the original equilibrium field and generate a field-reversed-configuration. In a conventional rotamak, a toroidal field (TF) is not necessary for the RMF to drive plasma current, but it was found that the present of an additional TF can influence the RMF current drive. In this paper the effect of TF on the RMF current drive in a rotamak are investigated in some detail.The experimental results show that addition of TF increases the RMF driven current greatly and enhances the RMF penetration dramatically. Without TF, the RMF can only penetrate into plasma in the edge region. When a TF is added, the RMF can reach almost the whole plasma region. This is an optimal strength of toroidal magnetic field for getting maximum plasma current when Bv and radio frequency generator power are fixed. Besides driving current,the RMF generates high harmonic fields in rotamak plasma. The effect of TF on the harmonic field spectra are also reported.

  19. Concept development and numerical analysis of tokamak heating and current drive

    Energy Technology Data Exchange (ETDEWEB)

    Ju, Myung Hee; Hong, Bong Guen [Korea Atomic Energy Research Institute, Taejon (Korea)

    1998-10-01

    We have done the analytical study on the coupling between the KSTAR plasma and RF antenna necessary for the engineering design of the KSTAR auxiliary heating and current drive system as well as the KSTAR RF antenna. With the code TORIC, the possible parameter ranges of tokamak heating and current drive operation modes using fast wave on the KSTAR are defined and analyzed. The optimized operation scenarios corresponding to the variety of KSTAR fast wave-driven heating and current drive parameters are also developed. With the code RANT3D, the characteristics of the coupling between the KSTAR plasma and RF antenna are analyzed, and the data for the conceptual design of 6 MW KSTAR RF antenna are achieved. Finally the optimum heating and current drive scenarios for the 3 KSTAR operation modes (the baseline reference mode, the upgrade reference mode, the reverse shear mode) using ACCOME and WHIST are developed, and it was shown that they can be realized in KSTAR tokamak with the planned heating and current drive systems. (author). 20 refs., 39 figs., 3 tabs.

  20. Large-Eddy Simulation: Current Capabilities, Recommended Practices, and Future Research

    Science.gov (United States)

    Georgiadis, Nicholas J.; Rizzetta, Donald P.; Fureby, Christer

    2009-01-01

    This paper presents the results of an activity by the Large Eddy Simulation (LES) Working Group of the AIAA Fluid Dynamics Technical Committee to (1) address the current capabilities of LES, (2) outline recommended practices and key considerations for using LES, and (3) identify future research needs to advance the capabilities and reliability of LES for analysis of turbulent flows. To address the current capabilities and future needs, a survey comprised of eleven questions was posed to LES Working Group members to assemble a broad range of perspectives on important topics related to LES. The responses to these survey questions are summarized with the intent not to be a comprehensive dictate on LES, but rather the perspective of one group on some important issues. A list of recommended practices is also provided, which does not treat all aspects of a LES, but provides guidance on some of the key areas that should be considered.

  1. Investigation of lower hybrid current drive during H-mode in EAST tokamak

    Institute of Scientific and Technical Information of China (English)

    Li Miao-Hui; Liu Fu-Kun; Wang Mao; Xu Han-Dong; Wan Bao-Nian; Ding Bo-Jiang; Kong Er-Hua; Zhang Lei; Zhang Xin-Jun; Qian Jin-Ping; Yan Ning; Han Xiao-Feng; Shan Jia-Fang

    2011-01-01

    H-mode discharges with lower hybrid current drive (LHCD) alone are achieved in EAST divertor plasma over a wide parameter range.These H-mode discharges are characterized by a sudden drop in Dα emission and a spontaneous rise in main plasma density.Good lower hybrid (LH) coupling during H-mode is obtained by putting the plasma close to the antenna and by injecting D2 gas from a pipe near the grill mouse.The analysis of lower hybrid current drive properties shows that the LH deposition profile shifts off axis during H-mode,and current drive (CD) efficiency decreases due to the increase in density.Modeling results of H-mode discharges with a general ray tracing code GENRAY are reported.

  2. Lower hybrid current drive experiments on Alcator C-Mod: Comparison with theory and simulationa)

    Science.gov (United States)

    Bonoli, P. T.; Ko, J.; Parker, R.; Schmidt, A. E.; Wallace, G.; Wright, J. C.; Fiore, C. L.; Hubbard, A. E.; Irby, J.; Marmar, E.; Porkolab, M.; Terry, D.; Wolfe, S. M.; Wukitch, S. J.; Alcator C-Mod Team; Wilson, J. R.; Scott, S.; Valeo, E.; Phillips, C. K.; Harvey, R. W.

    2008-05-01

    Lower hybrid (LH) current drive experiments have been carried out on the Alcator C-Mod tokamak [I. H. Hutchinson et al., Phys. Plasmas 1, 1511 (1994)] using a radio-frequency system at 4.6GHz. Up to 900kW of LH power has been coupled and driven LH currents have been inferred from magnetic measurements by extrapolating to zero loop voltage, yielding an efficiency of neILHR0/PLH≈2.5±0.2×1019(A/W/m2). We have simulated the LH current drive in these discharges using the combined ray tracing/three-dimensional (r,v⊥,v∥) Fokker-Planck code GENRAY-CQL3D (R. W. Harvey and M. McCoy, in Proceedings of the IAEA Technical Committee Meeting on Simulation and Modeling of Thermonuclear Plasmas, Montreal, Canada, 1992) and found similar current drive efficiencies. The simulated profiles of current density from CQL3D, including both ohmic plus LH drive have been found to be in good agreement with the measured current density from a motional Stark effect diagnostic. Measurements of nonthermal x-ray emission confirm the presence of a significant fast electron population and the three-dimensional (r,v⊥,v∥) electron distribution function from CQL3D has been used in a synthetic diagnostic code to simulate the measured hard x-ray data.

  3. Analysis of JET LCHD/ICRH synergy experiments in terms of relativistic current drive theory

    Energy Technology Data Exchange (ETDEWEB)

    Start, D.F.H.; Baranov, Y.; Brusati, M.; Ekedahl, A.; Froissard, P.; Gormezano, C.; Jacquinot, J.; Paquin, L.; Rimini, F.G. [Commission of the European Communities, Abingdon (United Kingdom). JET Joint Undertaking; Cox, M.; Gardner, C.; O`Brien, M.R. [UKAEA Culham Lab., Abingdon (United Kingdom); Di Vita, A. [Ansaldo SpA, Genoa (Italy)

    1994-07-01

    The present analysis shows that the observed efficiency of current drive with synergy between LHCD and ICRH is in good agreement with the relativistic theory of Karney and Fisch for Landau damped waves. The predicted power absorption from the fast wave by the electron tail is within 30% of the measured value. In the presence of significant fast electron diffusion within a slowing down time it would be possible to produce central current drive using multiple ICRF resonances even when the LHCD deposition is at half radius, as in an ITER type device. (authors). 4 refs., 6 figs.

  4. Design of long-pulse fast wave current drive antennas for DIII-D

    Science.gov (United States)

    Baity, F. W.; Batchelor, D. B.; Bills, K. C.; Fogelman, C. H.; Jaeger, E. F.; Ping, J. L.; Riemer, B. W.; Ryan, P. M.; Stallings, D. C.; Taylor, D. J.; Yugo, J. J.

    1994-10-01

    Two new long-pulse fast wave current drive (FWCD) antennas will be installed on DIII-D in early 1994. These antennas will increase the available FWCD power from 2 MW to 6 MW for pulse lengths of up to 2 s, and to 4 MW for up to 10 s. Power for the new antennas is from two ASDEX-type 30- to 120-MHz transmitters. When operated at 90° phasing into a low-density plasma (˜4×1019m-3) with hot electrons (˜10 keV), these two new antennas are predicted to drive approximately 1 MA of plasma current.

  5. Five-Level Current-Source Inverters With Buck–Boost and Inductive-Current Balancing Capabilities

    DEFF Research Database (Denmark)

    Gao, Feng; Loh, Poh Chiang; Blaabjerg, Frede

    2010-01-01

    This paper presents new five-level current-source inverters (CSIs) with voltage/current buck–boost capability, unlike existing five-level CSIs where only voltage–boost operation is supported. The proposed inverters attain self-inductive-currentbalancing per switching cycle at their dc front ends...... therefore be conveniently retrofitted for controlling the presented inverters. By appropriately coordinating the inverter gating signals, their implementations can be realized by using the least number of components without degrading performance. These enhanced features of the inverters have already been...

  6. Balancing Current Drive and Heating in DIII-D High Noninductive Current Fraction Discharges Through Choice of the Toroidal Field

    Energy Technology Data Exchange (ETDEWEB)

    Ferron, J.R. [General Atomics, San Diego; Holcomb, C T [Lawrence Livermore National Laboratory (LLNL); Luce, T.C. [General Atomics, San Diego; Politzer, P. A. [General Atomics, San Diego; Turco, F. [Oak Ridge Associated Universities (ORAU); DeBoo, J. C. [General Atomics; Doyle, E. J. [University of California, Los Angeles; In, Y. [FAR Tech Inc. San Diego, CA; La Haye, R. [General Atomics, San Diego; Murakami, Masanori [ORNL; Okabayashi, M. [Princeton Plasma Physics Laboratory (PPPL); Park, J. M. [Oak Ridge National Laboratory (ORNL); Petrie, T W [General Atomics, San Diego; Petty, C C. [General Atomics, San Diego; Reimerdes, H. [Columbia University

    2011-01-01

    In order to maintain stationary values of the stored energy and the plasma current in a tokamak discharge with all of the current driven noninductively, the sum of the alpha-heating power and the power required to provide externally driven current must be equal to the power required to maintain the pressure against transport losses. In a study of high noninductive current fraction discharges in the DIII-D tokamak, it is shown that in the case of present-day tokamaks with no alpha-heating, adjustment of the toroidal field strength (B(T)) is a tool to obtain this balance between the required current drive and heating powers with other easily modifiable discharge parameters (beta(N), q(95), discharge shape, n(e)) fixed at values chosen to satisfy specific constraints. With all of the external power sources providing both heating and current drive, and beta(N) and q(95) fixed, the fraction of externally driven current scales with B(T) with little change in the bootstrap current fraction, thus allowing the noninductive current fraction to be adjusted.

  7. Extracting DC bus current information for optimal phase correction and current ripple in sensorless brushless DC motor drive

    Institute of Scientific and Technical Information of China (English)

    Zu-sheng HO; Chii-maw UANG; Ping-chieh WANG

    2014-01-01

    Brushless DC motor (BLDCM) sensorless driving technology is becoming increasingly established. However, op-timal phase correction still relies on complex calculations or algorithms. In finding the correct commutation point, the problem of phase lag is introduced. In this paper, we extract DC bus current information for auto-calibrating the phase shift to obtain the correct commutation point and optimize the control of BLDC sensorless driving. As we capture only DC bus current information, the original shunt resistor is used in the BLDCM driver and there is no need to add further current sensor components. Software processing using only simple arithmetic operations successfully accomplishes the phase correction. Experimental results show that the proposed method can operate accurately and stably at low or high speed, with light or heavy load, and is suitable for practical applications. This approach will not increase cost but will achieve the best performance/cost ratio and meet market expectations.

  8. On the merits of heating and current drive for tearing mode stabilization

    Science.gov (United States)

    DeLazzari, D.; Westerhof, E.

    2009-07-01

    Neoclassical tearing modes (NTMs) are magnetohydrodynamic modes that can limit the performance of high β discharges in a tokamak, leading eventually to a plasma disruption. A NTM is sustained by the perturbation of the 'bootstrap' current, which is a consequence of the pressure flattening across a magnetic island. Control and suppression of this mode can be achieved by means of electron cyclotron waves (ECWs) which allow the deposition of highly localized power at the island location. The ECW power replenishes the missing bootstrap current by generating a current perturbation either inductively, through a temperature perturbation (electron cyclotron resonance heating), or non-inductively by direct current drive (electron cyclotron current drive). Although both methods have been applied successfully to experiments showing a predominance of ECRH for medium-sized limiter tokamaks (TEXTOR, T-10) and of ECCD for mid-to-large-sized divertor tokamaks (AUG, DIII-D, JT-60), conditions determining their relative importance are still unclear. We address this problem with a numerical study focused on the contributions of heating and current drive to the temporal evolution of NTMs as described by the modified Rutherford equation. For the effects of both heating as well as current drive, simple analytical expressions have been found in terms of an efficiency fore-factor times a 'geometrical' term depending on the power deposition width wdep, location and modulation. When the magnetic island width w equals the width of the deposition profile, w ≈ wdep, both geometric terms are practically identical. Whereas for current drive the geometric term approaches a constant for small island widths and is inversely proportional to (w/wdep)2 for large island widths, the heating term approaches a constant for large island widths and is proportional to (w/wdep) for small island widths. For medium-sized tokamaks (TEXTOR, AUG) the heating and current drive efficiencies are of the same order

  9. Lower hybrid heating and current drive in ignitor shear reversal scenarios

    Energy Technology Data Exchange (ETDEWEB)

    Barbato, E.; Pinaccione, L. [Italian Agengy for New Technologies, Energy and the Environment, Centro Ricerche Frascati, Rome (Italy). Dip. Energia

    1996-05-01

    Injection of Lower Hybrid (LH) Wave power at 8 GHz is considered into IGNITOR shear reversal scenarios, characterized by a reduced plasma current and density. Power deposition calculation are performed to establish whether LH waves can be used both as central heating and off axis current drive tool. It turns out that LH waves can be used (a) for central plasma heating purpose during the current vamp phase, to freeze the shear reversed configuration, at the power level of {approx}10 MW. (b) to drive a current in the outer part of the plasma at the power level of 20 MW. In this way around 1/3-1/6 of the total current in the proper plasma position (i.e. where q is minimum) is driven.

  10. Lower hybrid heating and current drive design for ITER and application for present tokamaks

    Energy Technology Data Exchange (ETDEWEB)

    Froissard, P.; Rey, G.; Bibet, P.; Goniche, M.; Kazarian, F.; Portafaix, C.; Tonon, G. [Association Euratom-CEA Cadarache, 13 - Saint-Paul-lez-Durance (France). Dept. de Recherches sur la Fusion Controlee; Bosia, G.; Bruno, L. [ITER Joint Work Site, Garching (Germany); Kuzikov, S. [Inst. of Applied Physics, Nizhny Novgorod (Russian Federation); Wasastjerna, F. [VTT Energy (Finland)

    1998-07-01

    The lower Hybrid Heating and Current Drive (LHH and CD) System shall provide on ITER off-axis current profile control during burn, main contribution to the non-inductive current generation in the advanced Tokamak scenario, current profile tailoring during ramp up phase, heating and current drive during plasma shut-down, extension of the pulse duration during commissioning phase. The LHH and CD system operates at 5 GHz, this frequency being a trade-off between power absorption by alpha particles and klystron technology and couples a minimum of 50 MW using two ITER ports. This article describes the launcher plug and the transmission lines. Specific converters, such as the mode converters, RF windows and the hyper-guide have now been successfully tested at high power and long pulse duration.

  11. Theory and experiments on RF plasma heating, current drive and profile control in TORE SUPRA

    Energy Technology Data Exchange (ETDEWEB)

    Moreau, D.

    1994-01-01

    This paper reviews the main experimental and theoretical achievements related to the study of RF heating and non-inductive current drive and particularly phenomena related to the current density profile control and the potentiality of producing stationary enhanced performance regimes: description of the Lower Hybrid (LH) and Ion Cyclotron Resonant Frequency (ICRF) systems; long pulse coupling performance of the RF systems; observation of the transition to the so-called ``stationary LHEP regime`` in which the (flat) central current density and (peaked) electron temperature profiles are fully decoupled; experiments on ICRF sawtooth stabilization with the combined effect of LHCD modifying the current density profile; diffusion of fast electrons generated by LH waves; ramp-up experiments in which the LH power provided a significant part of the resistive poloidal flux and flux consumption scaling; theory of spectral wave diffusion and multipass absorption; fast wave current drive modelling with the Alcyon full wave code; a reflector LH antenna concept. 18 figs., 48 refs.

  12. Application of drive circuit based on L298N in direct current motor speed control system

    Science.gov (United States)

    Yin, Liuliu; Wang, Fang; Han, Sen; Li, Yuchen; Sun, Hao; Lu, Qingjie; Yang, Cheng; Wang, Quanzhao

    2016-10-01

    In the experiment of researching the nanometer laser interferometer, our design of laser interferometer circuit system is up to the wireless communication technique of the 802.15.4 IEEE standard, and we use the RF TI provided by Basic to receive the data on speed control system software. The system's hardware is connected with control module and the DC motor. However, in the experiment, we found that single chip microcomputer control module is very difficult to drive the DC motor directly. The reason is that the DC motor's starting and braking current is larger than the causing current of the single chip microcomputer control module. In order to solve this problem, we add a driving module that control board can transmit PWM wave signal through I/O port to drive the DC motor, the driving circuit board can come true the function of the DC motor's positive and reversal rotation and speed adjustment. In many various driving module, the L298N module's integrated level is higher compared with other driver module. The L298N model is easy to control, it not only can control the DC motor, but also achieve motor speed control by modulating PWM wave that the control panel output. It also has the over-current protection function, when the motor lock, the L298N model can protect circuit and motor. So we use the driver module based on L298N to drive the DC motor. It is concluded that the L298N driver circuit module plays a very important role in the process of driving the DC motor in the DC motor speed control system.

  13. Influence of various physics phenomena on fast-wave current drive in advanced tokamaks

    Energy Technology Data Exchange (ETDEWEB)

    Batchelor, D.B.; Jaeger, E.F.; Carter, M.D.; Goldfinger, R.C.; Stallings, D.C. [Oak Ridge National Lab., TN (United States)

    1992-12-31

    The need for some type of noninductive current drive in advanced tokamaks has been recognized for some time. In reactor-grade plasmas, as envisioned in the International Thermonuclear Experimental Reactor (ITER), high density and temperature may limit the penetration of lower hybrid (LH) waves to only the outer layers of the plasma. Fast waves in the ion cyclotron range of frequencies (ICRF), however, can easily penetrate to the center of such high-density plasmas. With sufficient directivity in the launched wave spectrum, currents can be driven by combined damping of the fast waves on resonant electrons through electron Landau damping (ELD) and transit-time magnetic pumping (TTMP). Experiments to study the feasibility of fast-wave current drive (FWCD) have only recently begun, but theoretical predictions look promising. In this paper we analyze the influence of the relevant physics phenomena, which are not necessarily independent, on current drive performance. Such phenomena include diffraction and other nongeometrical optics processes, k{sub ||} modification, single-pass absorption, and antenna characteristics, such as poloidal extent and poloidal location. To do this, we apply a two-and-one-half dimensional (2 1/2-D), full-wave code (PICES) for modeling ion cyclotron resonance heating (ICRH) and current drive based on the poloidal mode expansion method and the reduced-order expansion. By 2 1/2-D, we mean that 3-D wave fields are calculated in axisymmetric geometry (2-D solution domain - r, {theta}), while the correct toroidal dependence of the antenna source currents is obtained from a 2-D (r, {phi}) recessed antenna code. The model includes the poloidal and toroidal structure of the antennas, the modification of the k{sub ||} spectrum due to the poloidal magnetic field, and a nonperturbative solution for E{sub ||}. A semianalytical model for current drive, including trapped electron effects, is employed. (author) 10 refs., 4 figs.

  14. Lower Hybrid Heating and Current Drive on the Alcator C-Mod Tokamak

    Energy Technology Data Exchange (ETDEWEB)

    R. Wilson, R. Parker, M. Bitter, P.T. Bonoli, C. Fiore, R.W. Harvey, K. Hill, A.E. Hubbard, J.W. Hughes, A. Ince-Cushman, C. Kessel, J.S. Ko, O. Meneghini, C.K. Phillips, M. Porkolab, J. Rice, A.E. Schmidt, S. Scott,S. Shiraiwa, E. Valeo, G.Wallace, J.C. Wright and the Alcator C-Mod Team

    2009-11-20

    On the Alcator C-Mod tokamak, lower hybrid current drive (LHCD) is being used to modify the current profile with the aim of obtaining advanced tokamak (AT) performance in plasmas with parameters similar to those that would be required on ITER. To date, power levels in excess of 1 MW at a frequency of 4.6 GHz have been coupled into a variety of plasmas. Experiments have established that LHCD on C-Mod behaves globally as predicted by theory. Bulk current drive efficiencies, n20IlhR/Plh ~ 0.25, inferred from magnetics and MSE are in line with theory. Quantitative comparisons between local measurements, MSE, ECE and hard x-ray bremsstrahlung, and theory/simulation using the GENRAY, TORIC-LH CQL3D and TSC-LSC codes have been performed. These comparisons have demonstrated the off-axis localization of the current drive, its magnitude and location dependence on the launched n|| spectrum, and the use of LHCD during the current ramp to save volt-seconds and delay the peaking of the current profile. Broadening of the x-ray emission profile during ICRF heating indicates that the current drive location can be controlled by the electron temperature, as expected. In addition, an alteration in the plasma toroidal rotation profile during LHCD has been observed with a significant rotation in the counter current direction. Notably, the rotation is accompanied by peaking of the density and temperature profiles on a current diffusion time scale inside of the half radius where the LH absorption is taking place.

  15. A mechanism for the dynamo terms to sustain closed-flux current, including helicity balance, by driving current which crosses the magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Jarboe, T. R.; Nelson, B. A.; Sutherland, D. A. [University of Washington, Seattle, Washington 98195 (United States)

    2015-07-15

    An analysis of imposed dynamo current drive (IDCD) [T.R. Jarboe et al., Nucl. Fusion 52 083017 (2012)] reveals: (a) current drive on closed flux surfaces seems possible without relaxation, reconnection, or other flux-surface-breaking large events; (b) the scale size of the key physics may be smaller than is often computationally resolved; (c) helicity can be sustained across closed flux; and (d) IDCD current drive is parallel to the current which crosses the magnetic field to produce the current driving force. In addition to agreeing with spheromak data, IDCD agrees with selected tokamak data.

  16. Evolution of the Tore Supra Lower Hybrid Current Drive System for WEST

    Energy Technology Data Exchange (ETDEWEB)

    Delpech, Léna, E-mail: lena.delpech@cea.fr [CEA, IRFM, F-13108 St Paul-Lez-Durance (France); Achard, Joelle; Armitano, Arthur; Berger-By, Gilles; Ekedahl, Annika; Gargiulo, Laurent; Goniche, Marc; Guilhem, Dominique; Hertout, Patrick; Hillairet, Julien; Magne, Roland; Mollard, Patrick [CEA, IRFM, F-13108 St Paul-Lez-Durance (France); Piluso, P. [CNIM Industrial Systems, 83507 La Seyne-sur-Mer (France); Poli, Serge; Prou, Marc; Saille, Alain; Samaille, Franck [CEA, IRFM, F-13108 St Paul-Lez-Durance (France)

    2015-10-15

    Highlights: • Describe the state of the Lower Hybrid heating system for the WEST project. • Detailed the experiments to assess the coupling in WEST configuration. • Give the modifications required on the launchers to be adapted to WEST configuration. • Detailed the technical modifications with the CNIM company on the launchers. - Abstract: The WEST-project (W-tungsten Environment in Steady-state Tokamak) involves equipping Tore Supra with a full tungsten divertor, capable of withstanding heat load of 10 MW/m{sup 2} in steady-state conditions, in discharges sustained by Lower Hybrid Current Drive (LHCD). The LHCD generator, recently upgraded to deliver 9.2 MW/1000 s, is equipped with sixteen TH2103C klystrons powering two launchers. The WEST transformation involves reducing the plasma volume, thus moving the launchers ∼10 cm closer to the tokamak centre. The toroidal curvature of the launchers no longer fits the plasma curvature due to the strong magnetic field ripple effect, leading to a degradation of the LH wave coupling, especially with the Full Active Multijunction Launcher (FAM). The toroidal curvature radius of the FAM launcher mouth will therefore be reshaped from 1700 mm to 2300 mm. The machining process is described in this article. In order to improve the coupling of the LH wave, the local gas injection has been modified to help to meet the requirement of 7 MW/1000 s of LH power coupled to the plasma in the WEST scenarios. Finally, the curvature radius of the waveguide septa are rounded to minimize the excitation of suprathermal electrons near the plasma edge, which can induce high power loads on the plasma facing components.

  17. Compensation methods applied in current control schemes for large AC drive systems

    DEFF Research Database (Denmark)

    Rus, D. C.; Preda, N. S.; Teodorescu, Remus;

    2012-01-01

    The paper deals with modified PI current control structures for large AC drive systems which use surface mounted permanent magnet synchronous machines or squirrel-cage induction motors supplied with voltage source inverters. In order to reduce the power losses caused by high frequency switching...

  18. Advanced launcher design options for electron cyclotron current drive on ITER based on remote steering

    NARCIS (Netherlands)

    Graswinckel, M. R.; Bongers, W. A.; M.R. de Baar,; van den Berg, M. A.; Denisov, G.; Donne, A. J. H.; Elzendoorn, B. S. Q.; Goede, A. P. H.; Heidinger, R.; Kuzikov, S.; Kruijt, O. G.; Kruizinga, B.; Moro, A.; Poli, E.; Ronden, D. M. S.; Saibene, G.; Thoen, D. J.; Verhoeven, A. G. A.

    2008-01-01

    Electron cyclotron current drive will become the main scheme on ITER for the stabilization of neoclassical tearing modes (NTMs) and the control of sawtooth oscillations. The effectiveness of this scheme forms the basis for the requirements of the ITER Upper Port Launcher. These requirements include

  19. Application of High Harmonic Fast Waves to Off-Axis Current Drive in DIII-D

    Science.gov (United States)

    Prater, R.; Pinsker, R. I.; Moeller, C. P.; Porkolab, M.; Vdovin, V. L.

    2013-10-01

    High harmonic fast waves, also called ``whistlers'' or ``helicons,'' may be an effective means of driving current off-axis in high performance discharges in DIII-D. Modeling using the GENRAY ray tracing code APP shows that fast waves launched with frequency 500 MHz tend to spiral around the magnetic axis. If the electron beta is above 1.7%, the waves are damped around ρ = 0 . 5 for a broad range of conditions. The fast wave current drive in the test discharge is 2 to 4 times larger per MW than that from the electron cyclotron heating or neutral beam injection systems on DIII-D. Interestingly, the current drive location and magnitude are nearly independent of the launched n| | over the range 2 to 4. Use of a moderately large value, n| | = 3 , reduces the possibility of mode conversion to the slow wave. A traveling wave antenna is expected to be effective at launching the wave with a narrow spectrum of n| |, which also helps avoid mode conversion. A test of the physics of high harmonic fast wave current drive is planned for DIII-D. Work supported in part by the US Department of Energy under DE-FC02-04ER54698.

  20. Fast-ion transport and neutral beam current drive in ASDEX upgrade

    DEFF Research Database (Denmark)

    Geiger, B.; Weiland, M.; Jacobsen, Asger Schou

    2015-01-01

    The neutral beam current drive efficiency has been investigated in the ASDEX Upgrade tokamak by replacing on-axis neutral beams with tangential off-axis beams. A clear modification of the radial fast-ion profiles is observed with a fast-ion D-alpha diagnostic that measures centrally peaked profil...

  1. Globalisation and the foreignisation of space: The seven processes driving the current global land grab.

    NARCIS (Netherlands)

    Zoomers, E.B.

    2010-01-01

    The current global land grab is causing radical changes in the use and ownership of land. The main process driving the land grab, or ‘foreignisation of space’, as highlighted in the media and the emerging literature is the production of food and biofuel for export in the aftermath of recent food and

  2. Heating, current drive and energetic particle studies on JET in preparation of ITER operation

    NARCIS (Netherlands)

    Noterdaeme, J. M.; Budny, R.; Cardinali, A.; Castaldo, C.; Cesario, R.; Crisanti, F.; DeGrassie, J.; D' Ippolito, D. A.; Durodie, F.; Ekedahl, A.; Figueiredo, A.; Ingesson, C.; Joffrin, E.; Hartmann, D.; Heikkinen, J.; Hellsten, T.; Jones, T.; Kiptily, V.; Lamalle, P.; Litaudon, X.; Nguyen, F.; Mailloux, J.; Mantsinen, M.; Mayoral, M.; Mazon, D.; Meo, F.; Monakhov, I.; Myra, J. R.; Pamela, J.; Pericoli, V.; Petrov, Y.; Sauter, O.; Sarazin, Y.; Sharapov, S. E.; Tuccillo, A. A.; Van Eester, D.

    2003-01-01

    This paper summarizes the recent work on JET in the three areas of heating, current drive and energetic particles. The achievements have extended the possibilities of JET, have a direct connection to ITER operation and provide new and interesting physics. Toroidal rotation profiles of plasmas heated

  3. Study of multipass regimes in lower hybrid current drive experiments on Tore Supra

    Energy Technology Data Exchange (ETDEWEB)

    Arslanbekov, R.; Litaudon, X.; Peysson, Y.; Hoang, G.T.; Kazarian, F.; Moreau, D. [Association Euratom-CEA, Centre d`Etudes de Cadarache, 13 - Saint-Paul-lez-Durance (France). Dept. de Recherches sur la Fusion Controlee; Shoucri, M.; Shkarofsky, I.P. [Centre Canadien de Fusion Magnetique, Varennes, PQ (Canada); Baranov, Y. [Commission of the European Communities, Abingdon (United Kingdom). JET Joint Undertaking; Kupfer, K. [General Atomics, San Diego, CA (United States)

    1995-12-31

    This document presents a study of multipass regimes in Lower Hybrid Current Drive on Tore Supra. A statistical model of the plasma wave propagation based on the Fokker-Planck theory is proposed, together with experimental results performed on Tore Supra. (TEC). 9 refs., 4 figs.

  4. Lower Hybrid Wave Current Drive Efficiency on the HT-7 Tokamak

    Institute of Scientific and Technical Information of China (English)

    CHEN Zhong-Yong; WAN Bao-Nian; SHI Yue-Jiang; HU Li-Qun; XU Han-Dong; LI Guo-Chao

    2005-01-01

    @@ Lower hybrid (LH) wave current drive efficiency on our HT-7 tokamak has been investigated based on the hot electrical conductivity theory.The interaction of the residual toroidal electric field with fast electrons has been included in the determination of current drive efficiency.The LH wave power scan was performed in the plasma parameter ranges of Ip = 50-156kA, (n)e = 0.5 × 1019-1.6 × 1019 m-3, PLH = 50-350kW.The current drive efficiency is derived to be about 0.1 × 1019-0.4 × 1019 Am-2W-1 on the HT-7 tokamak, which depends on the electron density and the LH wave phase velocity.At the electron density of about 1.5 × 1019 m-3, with the LH wave parallel refraction index peaked at 1.8, the highest current drive efficiency was obtained.A more generally normalized method is introduced to analyse the experimental data, which combines all the data in one curve.The normalized parameters are independent of the plasma parameters.

  5. Impact of heating and current drive mix on the ITER hybrid scenario

    NARCIS (Netherlands)

    Citrin, J.; Artaud, J. F.; Garcia, J.; Hogeweij, G. M. D.; Imbeaux, F.

    2010-01-01

    Hybrid scenario performance in ITER is studied with the CRONOS integrated modelling suite, using the GLF23 anomalous transport model for heat transport prediction. GLF23 predicted core confinement is optimized through tailoring the q-profile shape by a careful choice of current drive actuators, affe

  6. Fast wave current drive modeling using the combined RANT3D and PICES Codes

    Energy Technology Data Exchange (ETDEWEB)

    Jaeger, E.F.; Murakami, M.; Stallings, D.C.; Carter, M.D.; Wang, C.Y.; Galambos, J.D.; Batchelor, D.B.; Baity, F.W.; Bell, G.L.; Wilgen, J.B. [Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-8071 (United States); Chiu, S.C.; DeGrassie, J.S.; Forest, C.B. [General Atomics, San Diego, California 92186-9784 (United States); Kupfer, K. [ORISE Postdoctoral Fellow at General Atomics, San Diego, California 92186-9784 (United States); Petty, C.C.; Pinsker, R.T.; Prater, R.; Lohr, J. [General Atomics, San Diego, California 92186-9784 (United States); Lee, K.M. [University of California, Los Angeles, California 90024-1597 (United States)

    1996-02-01

    Two numerical codes are combined to give a theoretical estimate of the current drive and direct electron heating by fast waves launched from phased antenna arrays on the DIII-D tokamak. Results are compared with experiment. {copyright} {ital 1996 American Institute of Physics.}

  7. Benchmarking of codes for electron cyclotron heating and electron cyclotron current drive under ITER conditions

    NARCIS (Netherlands)

    Prater, R.; Farina, D.; Gribov, Y.; Harvey, R. W.; Ram, A. K.; Lin-Liu, Y. R.; Poli, E.; Smirnov, A. P.; Volpe, F.; Westerhof, E.; Zvonkovo, A.

    2008-01-01

    Optimal design and use of electron cyclotron heating requires that accurate and relatively quick computer codes be available for prediction of wave coupling, propagation, damping and current drive at realistic levels of EC power. To this end, a number of codes have been developed in laboratories wor

  8. U.S. Sodium Fast Reactor Codes and Methods: Current Capabilities and Path Forward

    Energy Technology Data Exchange (ETDEWEB)

    Brunett, A. J.; Fanning, T. H.

    2017-06-26

    The United States has extensive experience with the design, construction, and operation of sodium cooled fast reactors (SFRs) over the last six decades. Despite the closure of various facilities, the U.S. continues to dedicate research and development (R&D) efforts to the design of innovative experimental, prototype, and commercial facilities. Accordingly, in support of the rich operating history and ongoing design efforts, the U.S. has been developing and maintaining a series of tools with capabilities that envelope all facets of SFR design and safety analyses. This paper provides an overview of the current U.S. SFR analysis toolset, including codes such as SAS4A/SASSYS-1, MC2-3, SE2-ANL, PERSENT, NUBOW-3D, and LIFE-METAL, as well as the higher-fidelity tools (e.g. PROTEUS) being integrated into the toolset. Current capabilities of the codes are described and key ongoing development efforts are highlighted for some codes.

  9. Derivation of dynamo current drive in a closed-current volume and stable current sustainment in the HIT-SI experiment

    Science.gov (United States)

    Hossack, A. C.; Sutherland, D. A.; Jarboe, T. R.

    2017-02-01

    A derivation is given showing that the current inside a closed-current volume can be sustained against resistive dissipation by appropriately phased magnetic perturbations. Imposed-dynamo current drive theory is used to predict the toroidal current evolution in the helicity injected torus with steady inductive helicity injection (HIT-SI) experiment as a function of magnetic fluctuations at the edge. Analysis of magnetic fields from a HIT-SI discharge shows that the injector-imposed fluctuations are sufficient to sustain the measured toroidal current without instabilities whereas the small, plasma-generated magnetic fluctuations are not sufficiently large to sustain the current.

  10. "When can I return to driving?": a review of the current literature on returning to driving after lower limb injury or arthroplasty.

    Science.gov (United States)

    MacLeod, K; Lingham, A; Chatha, H; Lewis, J; Parkes, A; Grange, S; Smitham, P J

    2013-03-01

    Clinicians are often asked by patients, "When can I drive again?" after lower limb injury or surgery. This question is difficult to answer in the absence of any guidelines. This review aims to collate the currently available evidence and discuss the factors that influence the decision to allow a patient to return to driving. Medline, Web of Science, Scopus, and EMBASE were searched using the following terms: 'brake reaction time', 'brake response time', 'braking force', 'brake pedal force', 'resume driving', 'rate of application of force', 'driving after injury', 'joint replacement and driving', and 'fracture and driving'. Of the relevant literature identified, most studies used the brake reaction time and total brake time as the outcome measures. Varying recovery periods were proposed based on the type and severity of injury or surgery. Surveys of the Driver and Vehicle Licensing Agency, the Police, insurance companies in the United Kingdom and Orthopaedic Surgeons offered a variety of opinions. There is currently insufficient evidence for any authoritative body to determine fitness to drive. The lack of guidance could result in patients being withheld from driving for longer than is necessary, or returning to driving while still unsafe.

  11. Hysteretic self-oscillating bandpass current mode control for Class D audio amplifiers driving capacitive transducers

    DEFF Research Database (Denmark)

    Nielsen, Dennis; Knott, Arnold; Andersen, Michael A. E.

    2013-01-01

    A hysteretic self-oscillating bandpass current mode control (BPCM) scheme for Class D audio amplifiers driving capacitive transducers are presented. The scheme provides excellent stability margins and low distortion over a wide range of operating conditions. Small-signal behavior of the amplifier...... the rules of electrostatics have been known as very interesting alternatives to the traditional inefficient electrodynamic transducers. When driving capacitive transducers from a Class D audio amplifier the high impedance nature of the load represents a key challenge. The BPCM control scheme ensures a flat...... is analysis through transfer function based linear control methodology. Measurements are performed on a single-ended ± 300 V half-bridge amplifier driving a capacitive load of 100 nF. Total Harmonic Distortion plus noise (THD+N) below 0.1 % are reported. Transducers representing a capacitive load and obeying...

  12. High efficiency off-axis current drive by high frequency fast waves

    Science.gov (United States)

    Prater, R.; Pinsker, R. I.; Moeller, C. P.; Porkolab, M.; Vdovin, V.

    2014-02-01

    Modeling work shows that current drive can be done off-axis with high efficiency, as required for FNSF and DEMO, by using very high harmonic fast waves ("helicons" or "whistlers"). The modeling indicates that plasmas with high electron beta are needed in order for the current drive to take place off-axis, making DIII-D a highly suitable test vehicle for this process. The calculations show that the driven current is not very sensitive to the launched value of n∥, a result that can be understood from examination of the evolution of n∥ as the waves propagate in the plasma. Because of this insensitivity, relatively large values (˜3) of n∥ can be launched, thereby avoiding some of the problems with mode conversion in the boundary found in some previous experiments. Use of a traveling wave antenna provides a very narrow n∥ spectrum, which also helps avoid mode conversion.

  13. An analysis of JET fast-wave heating and current drive experiments directly related to ITER

    Energy Technology Data Exchange (ETDEWEB)

    Bhatnagar, V.P.; Eriksson, L.; Gormezano, C.; Jacquinot, J.; Kaye, A.; Start, D.F.H. [Commission of the European Communities, Abingdon (United Kingdom). JET Joint Undertaking

    1994-07-01

    The ITER fast-wave system is required to serve a variety of purposes, in particular, plasma heating to ignition, current profile and burn control and eventually, in conjunction with other schemes, a central non-inductive current drive (CD) for the steady-state operation of ITER. The ICRF heating and current drive data that has been obtained in JET are analyzed in terms of dimensionless parameters, with a view to ascertaining its direct relevance to key ITER requirements. The analysis is then used to identify areas both in physics and technological aspects of ion-cyclotron resonance heating (ICRH) and CD that require further experimentation in ITER-relevant devices such as JET to establish the required data base. (authors). 12 refs., 8 figs.

  14. A Smart Current Modulation Scheme for Harmonic Reduction in Three- Phase Motor Drive Applications

    DEFF Research Database (Denmark)

    Davari, Pooya; Zare, Firuz; Blaabjerg, Frede

    2015-01-01

    harmonic mitigation methods have been developed over the years, the total cost and complexity has become the main obstacle in employing prior-art methods for motor drive systems. This paper presents a novel current modulation method based on the electronic inductor concept for three-phase ac-dc systems......Electric motor-driven systems consume considerable amount of the global electricity. Majority of three-phase motor drives are equipped with conventional diode rectifier and passive harmonic mitigation, being witnessed as the main source in generating input current harmonics. While many active...... to reduce input current harmonics. The obtained results at simulation and experimental levels confirm the effectiveness of the proposed approach....

  15. On radio frequency current drive in the ion cyclotron range of frequencies in DEMO and large ignited plasmas

    Science.gov (United States)

    Brambilla, Marco; Bilato, Roberto

    2015-02-01

    To explore the possibility of efficient fast wave current drive in an ignited plasma in the ion cyclotron (IC) range of frequency in spite of competition from absorption by ions, we have added to the full-wave toroidal code TORIC a set of subroutines which evaluate absorption by these particles at IC harmonic resonances, using a realistic ‘slowing-down’ distribution function, and taking into account that their Larmor radius is comparable or even larger than the fast wave wavelength. The thermalized population of α-particles is not a serious competitor for power absorption as long as their number density is compatible with maintenance of ignition. By contrast, the energetic slowing down fraction, in spite of its even greater dilution, can absorb from the waves a substantial amount of power at the cyclotron resonance and its harmonics. An extensive exploration both in frequency and in toroidal wavenumbers using the parameters of one of the European versions of DEMO shows that three frequency windows exist in which damping is nevertheless predominantly on the electrons. Designing an antenna capable of shaping the launched spectrum to optimize current drive, however, will not be straightforward. Only in a narrow range when the first IC harmonic of tritium is deep inside the plasma on the high-field side of the magnetic axis, and that of deuterium and helium is still outside on the low-field side, it appears possible to achieve a satisfactory current drive efficiency with a conventional multi-strap antenna, preferentially located in the upper part of the vessel. Exploiting the other two windows at quite low and quite high frequencies is either impossible on first principles, or will demand novel ideas in antenna design.

  16. A Phase Current Reconstruction Approach for Three-Phase Permanent-Magnet Synchronous Motor Drive

    Directory of Open Access Journals (Sweden)

    Hao Yan

    2016-10-01

    Full Text Available Three-phase permanent-magnet synchronous motors (PMSMs are widely used in renewable energy applications such as wind power generation, tidal energy and electric vehicles owing to their merits such as high efficiency, high precision and high reliability. To reduce the cost and volume of the drive system, techniques of reconstructing three-phase current using a single current sensor have been reported for three-phase alternating current (AC control system using the power converts. In existing studies, the reconstruction precision is largely influenced by reconstructing dead zones on the Space Vector Pulse Width Modulation (SVPWM plane, which requires other algorithms to compensate either by modifying PWM modulation or by phase-shifting of the PWM signal. In this paper, a novel extended phase current reconstruction approach for PMSM drive is proposed. Six novel installation positions are obtained by analyzing the sampling results of the current paths between each two power switches. By arranging the single current sensor at these positions, the single current sensor is sampled during zero voltage vectors (ZVV without modifying the PWM signals. This proposed method can reconstruct the three-phase currents without any complex algorithms and is available in the sector boundary region and low modulation region. Finally, this method is validated by experiments.

  17. Current Reversal Due to Coupling Between Asymmetrical Driving Force and Ratchet Potential

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Transport of a Brownian particle moving in a periodic potential is investigated in the presence of an asymmetric unbiased external force. The asymmetry of the external force and the asymmetry of the potential are the two ways of inducing a net current. It is found that the competition of the spatial asymmetry of potential with the temporal asymmetry of the external force leads to the phenomena like current reversal. The competition between the two opposite driving factors is a necessary but not a sufficient condition for current reversals.

  18. Extreme Environment Simulation - Current and New Capabilities to Simulate Venus and Other Planetary Bodies

    Science.gov (United States)

    Kremic, Tibor; Vento, Dan; Lalli, Nick; Palinski, Timothy

    2014-01-01

    Science, technology, and planetary mission communities have a growing interest in components and systems that are capable of working in extreme (high) temperature and pressure conditions. Terrestrial applications range from scientific research, aerospace, defense, automotive systems, energy storage and power distribution, deep mining and others. As the target environments get increasingly extreme, capabilities to develop and test the sensors and systems designed to operate in such environments will be required. An application of particular importance to the planetary science community is the ability for a robotic lander to survive on the Venus surface where pressures are nearly 100 times that of Earth and temperatures approach 500C. The scientific importance and relevance of Venus missions are stated in the current Planetary Decadal Survey. Further, several missions to Venus were proposed in the most recent Discovery call. Despite this interest, the ability to accurately simulate Venus conditions at a scale that can test and validate instruments and spacecraft systems and accurately simulate the Venus atmosphere has been lacking. This paper discusses and compares the capabilities that are known to exist within and outside the United States to simulate the extreme environmental conditions found in terrestrial or planetary surfaces including the Venus atmosphere and surface. The paper then focuses on discussing the recent additional capability found in the NASA Glenn Extreme Environment Rig (GEER). The GEER, located at the NASA Glenn Research Center in Cleveland, Ohio, is designed to simulate not only the temperature and pressure extremes described, but can also accurately reproduce the atmospheric compositions of bodies in the solar system including those with acidic and hazardous elements. GEER capabilities and characteristics are described along with operational considerations relevant to potential users. The paper presents initial operating results and concludes

  19. Single-current-sensor-based active front-end-converter-fed four quadrants induction motor drive

    Indian Academy of Sciences (India)

    JOSEPH KIRAN BANDA; AMIT KUMAR JAIN

    2017-08-01

    Induction motor (IM) is a workhorse of the industry, whose dynamics can be modified close to that of a separately excited DC machine by field-oriented control technique, which is commonly known as vector control of induction machine. This paper presents a complete performance of the field-oriented control of IM drive in all four quadrants with a single-current-sensor-based active front end converter whose work is to regulate DC link voltage, draw pure sinusoidal currents at unity power factor and to facilitate bi-directional power flow between the grid and the drive. The entire system is completely modelled in MATLAB/SIMULINK and the results are discussed in detail. The vector control analogy of the back to back converters is highlighted along with the experimental results of field-oriented control of induction machine using a dsPIC30F6010A digital signal controller.

  20. Redundant drive current imbalance problem of the Automatic Radiator Inspection Device (ARID)

    Science.gov (United States)

    Latino, Carl D.

    1992-09-01

    The Automatic Radiator Inspection Device (ARID) is a 4 Degree of Freedom (DOF) robot with redundant drive motors at each joint. The device is intended to automate the labor intensive task of space shuttle radiator inspection. For safety and redundancy, each joint is driven by two independent motor systems. Motors driving the same joint, however, draw vastly different currents. The concern was that the robot joints could be subjected to undue stress. It was the objective of this summer's project to determine the cause of this current imbalance. In addition it was to determine, in a quantitative manner, what was the cause, how serious the problem was in terms of damage or undue wear to the robot and find solutions if possible. It was concluded that most problems could be resolved with a better motor control design. This document discusses problems encountered and possible solutions.

  1. Design of long-pulse fast wave current drive antennas for DIII-D

    Energy Technology Data Exchange (ETDEWEB)

    Baity, F.W.; Batchelor, D.B.; Bills, K.C.; Fogelman, C.H.; Jaeger, E.F.; Ping, J.L.; Riemer, B.W.; Ryan, P.M.; Stallings, D.C.; Taylor, D.J.; Yugo, J.J. (Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-8071 (United States))

    1994-10-15

    Two new long-pulse fast wave current drive (FWCD) antennas will be installed on DIII-D in early 1994. These antennas will increase the available FWCD power from 2 MW to 6 MW for pulse lengths of up to 2 s, and to 4 MW for up to 10 s. Power for the new antennas is from two ASDEX-type 30- to 120-MHz transmitters. When operated at 90[degree] phasing into a low-density plasma ([similar to]4[times]10[sup 19]m[sup [minus]3]) with hot electrons ([similar to]10 keV), these two new antennas are predicted to drive approximately 1 MA of plasma current.

  2. Design of Current Controller for Two Quadrant DC Motor Drive by Using Model Order Reduction Technique

    CERN Document Server

    Ramesh, K; Nirmalkumar, A; Gurusamy, G

    2010-01-01

    In this paper, design of current controller for a two quadrant DC motor drive was proposed with the help of model order reduction technique. The calculation of current controller gain with some approximations in the conventional design process is replaced by proposed model order reduction method. The model order reduction technique proposed in this paper gives the better controller gain value for the DC motor drive. The proposed model order reduction method is a mixed method, where the numerator polynomial of reduced order model is obtained by using stability equation method and the denominator polynomial is obtained by using some approximation technique preceded in this paper. The designed controllers responses were simulated with the help of MATLAB to show the validity of the proposed method.

  3. Fast electron dynamics in lower hybrid current drive experiment on HT-7 tokamak

    Institute of Scientific and Technical Information of China (English)

    Shi Yue-Jiang; Kuang Gang-Li; Li Jian-Gang; HT-7 Team; Wan Bao-Nian; Chen Zhong-Yong; Hu Li-Qun; Lin Shi-Yao; Ruan Huai-Lin; Qian Jin-Ping; Zhen Xiang-Jun; Ding Bo-Jiang

    2005-01-01

    The dynamic behaviour of fast electron in lower hybrid current drive (LHCD) experiments is a crucial issue in the sense of enhancing plasma performance. A new hard x-ray diagnostic system on HT-7 allows the investigation of the lower hybrid wave dynamics. The behaviour of fast electron is studied in several kinds of LHCD experiments, including long pulse discharges, high performance discharges and counter-LHCD experiments.

  4. First principles fluid modelling of magnetic island stabilization by electron cyclotron current drive (ECCD)

    Science.gov (United States)

    Février, O.; Maget, P.; Lütjens, H.; Luciani, J. F.; Decker, J.; Giruzzi, G.; Reich, M.; Beyer, P.; Lazzaro, E.; Nowak, S.; the ASDEX Upgrade Team

    2016-04-01

    Tearing modes are MagnetoHydroDynamics (MHD) instabilities that reduce the performance of fusion devices. They can however be controlled and suppressed using electron cyclotron current drive (ECCD) as demonstrated in various tokamaks. In this work, simulations of island stabilization by ECCD-driven current have been carried out using the toroidal nonlinear 3D full MHD code xtor-2f, in which a current source term modeling the ECCD has been implemented. The efficiency parameter, {η\\text{RF}} , has been computed and its variations with respect to source width and location were also computed. The influence of parameters such as current intensity, source width and position with respect to the island was evaluated and compared to the modified Rutherford equation. We retrieved a good agreement between the simulations and the analytical predictions concerning the variations of control efficiency with source width and position. We also show that the 3D nature of the current source term can lead to the onset of an island if the source term is precisely applied on a rational surface. We report the observation of a flip phenomenon in which the O- and X-points of the island rapidly switch their position in order for the island to take advantage of the current drive to grow.

  5. Study of lower hybrid current drive system in tokamak fusion devices

    Energy Technology Data Exchange (ETDEWEB)

    Maebara, Sunao [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2001-01-01

    This report describes R and D of a high-power klystron, RF vacuum window, low-outgassing antenna and a front module for a plasma-facing antenna aiming the 5 GHz Lower Hybrid Current Drive (LHCD) system for the next Tokamak Fusion Device. 5 GHz klystron with a low-perveances of 0.7 {mu}P is designed for a high-power and a high-efficiency, the output-power of 715 kW and the efficiency of 63%, which are beyond the conventional design scaling of 450 kW-45%, are performed using the prototype klystron which operates at the pulse duration of 15 {mu}sec. A new pillbox window, which has an oversized length in both the axial and the radial direction, are designed to reduce the RF power density and the electric field strength at the ceramics. It is evaluated that the power capability by cooling edge of ceramics is 1 MW with continuous-wave operation. The antenna module using Dispersion Strengthened Copper which combines high mechanical property up to 500degC with high thermal conductivity, are developed for a low-outgassing antenna in a steady state operation. It is found that the outgassing rate is in the lower range of 4x10{sup -6} Pam{sup 3}/sm{sup 2} at the module temperature of 300degC, which requires no active vacuum pumping of the LHCD antenna. A front module using Carbon Fiber Composite (CFC) are fabricated and tested for a plasma facing antenna which has a high heat-resistive. Stationary operation of the CFC module with water cooling is performed at the RF power of 46 MWm{sup -2} (about 2 times higher than the design value) during 1000 sec, it is found that the outgassing rate is less than 10{sup -5} Pam{sup 3}/sm{sup 2} which is low enough for an antenna material. (author)

  6. Potential of ion cyclotron resonance frequency current drive via fast waves in DEMO

    Science.gov (United States)

    Kazakov, Ye O.; Van Eester, D.; Wauters, T.; Lerche, E.; Ongena, J.

    2015-02-01

    For the continuous operation of future tokamak-reactors like DEMO, non-inductively driven toroidal plasma current is needed. Bootstrap current, due to the pressure gradient, and current driven by auxiliary heating systems are currently considered as the two main options. This paper addresses the current drive (CD) potential of the ion cyclotron resonance frequency (ICRF) heating system in DEMO-like plasmas. Fast wave CD scenarios are evaluated for both the standard midplane launch and an alternative case of exciting the waves from the top of the machine. Optimal ICRF frequencies and parallel wave numbers are identified to maximize the CD efficiency. Limitations of the high frequency ICRF CD operation are discussed. A simplified analytical method to estimate the fast wave CD efficiency is presented, complemented with the discussion of its dependencies on plasma parameters. The calculated CD efficiency for the ICRF system is shown to be similar to those for the negative neutral beam injection and electron cyclotron resonance heating.

  7. Telemedicine deployments within NATO military forces: a data analysis of current and projected capabilities.

    Science.gov (United States)

    Lam, David M; Poropatich, Ronald K

    2008-11-01

    Since the creation of the NATO Telemedicine Expert Panel (now renamed the TMED Expert Team) in 2000, when few nations had deployed telemedicine systems to support military field operations, this group has been encouraging the nations to deploy telemedicine (TMED) in support of their forces, and to write the use of TMED into NATO doctrine. This has been a relatively successful effort, and TMED is increasingly being used within the military medical structures of some NATO and Partnership for Peace nations to provide medical care to deployed military personnel. We report the results of a multinational survey of current and projected availability of various telemedicine modalities within the NATO medical services that are participating in the work of the TMED expert team (ET). Though only a "snapshot in time," and not representing all NATO nations, this is the first attempt to identify both current and planned TMED utilization within the multinational military medical community. Participating nations report that communication systems now in place at the lowest levels of medical support increasingly enable the routine use of Web-based teleconsultation modalities. Teleradiology is now being seen as the de facto standard for imaging support. While a number of nations report they have deployed capabilities for obtaining clinical consultations at a distance, most responding nations do not have a formal organizational structure to control and manage remote consultation and rely on informal clinical relationships (e.g., requesting consults from the deployed clinician's home hospital or from friends). Military electronic health records are in use by only a minority of nations and fewer still are capable of civilian interface. Less common TMED capabilities (e.g., tele-microbiology, tele-pathology, tele-medical maintenance) are being increasingly used, but are still rarely deployed. As a result of the findings of this survey, specific recommendations for expanding the use of

  8. A New High Speed Induction Motor Drive based on Field Orientation and Hysteresis Current Comparison

    Science.gov (United States)

    Ogbuka, Cosmas; Nwosu, Cajethan; Agu, Marcel

    2016-09-01

    This paper presents a new high speed induction motor drive based on the core advantage of field orientation control (FOC) and hysteresis current comparison (HCC). A complete closed loop speed-controlled induction motor drive system is developed consisting of an outer speed and an inner HCC algorithm which are optimised to obtain fast and stable speed response with effective current and torque tracking, both during transient and steady states. The developed model, being speed-controlled, was examined with step and ramp speed references and excellent performances obtained under full load stress. A speed response comparison of the model with the standard AC3 (Field-Oriented Control Induction Motor Drive) of MATLAB Simpower systems shows that the model achieved a rise time of 0.0762 seconds compared to 0.2930 seconds achieved by the AC3. Also, a settle time of 0.0775 seconds was obtained with the developed model while that of the AC3 model is 0.2986 seconds confirming, therefore, the superiority of the developed model over the AC3 model which, hitherto, served as a reference standard.

  9. Compact ASD Topologies for Single-Phase Integrated Motor Drives with Sinusoidal Input Current

    DEFF Research Database (Denmark)

    Klumpner, Christian; Blaabjerg, Frede; Thoegersen, Paul

    2005-01-01

    A standard configuration of an Adjustable Speed Drive (ASD) consists of two separate units: an AC motor, which runs with fixed speed when it is supplied from a constant frequency grid voltage and a frequency converter, which is used to provide the motor with variable voltage-variable frequency...... needed to adjust the speed of the motor. The integrated motor drive concept is a result of merging the two units in order to achieve the following benefits [1-3]: reducing the design and the commissioning time in complex industrial equipments, no need for a cabinet to host the frequency converter......, no needfor shielded cables to reduce EM1 (Electro Magnetic Inteiference), no needfor cables for the speed transducers or for other sensorsfor industrial process control (e.g. pressure). This solution is currently available up to 7.5 kW being not used in the medium and high power range due to a low...

  10. Input current interharmonics in adjustable speed drives caused by fixed-frequency modulation techniques

    DEFF Research Database (Denmark)

    Soltani, Hamid; Davari, Pooya; Loh, Poh Chiang

    2016-01-01

    Adjustable Speed Drives (ASDs) based on double-stage conversion systems may inject interharmonics distortion into the grid, other than the well-known characteristic harmonic components. The problems created by interharmonics make it necessary to find their precise sources, and, to adopt an approp......Adjustable Speed Drives (ASDs) based on double-stage conversion systems may inject interharmonics distortion into the grid, other than the well-known characteristic harmonic components. The problems created by interharmonics make it necessary to find their precise sources, and, to adopt...... an appropriate strategy for minimizing their effects. This paper investigates the ASD's input current interharmonic sources caused by applying symmetrical regularly sampled fixed-frequency modulation techniques on the inverter. The interharmonics generation process is precisely formulated and comparative results...

  11. Lower Hybrid Current Drive Experiments on Alcator C-Mod: Comparison with Theory and Simulation

    Science.gov (United States)

    Bonoli, Paul

    2007-11-01

    Recently, lower hybrid current drive (LHCD) experiments have been carried out on Alcator C-Mod using an RF system consisting of 12 klystrons at 4.6 GHz, feeding a 4 x 22 waveguide array. Up to 900 kW of LH power has been coupled in the range1.6 PLH 0.3 [1]. We have simulated the LH current drive in these discharges using the combined ray tracing / 3D (r, v, v//) Fokker Planck code GENRAY -- CQL3D [2] and found similar current drive efficiencies. Measurements of nonthermal x-ray emission and electron cyclotron emission (ECE) confirm the presence of a significant fast electron population that varies with waveguide phasing and plasma density. Studies are currently underway to investigate the role of fast electron diffusion and full-wave effects such as diffractional broadening in determining the spatial and velocity space structure of the nonthermal electrons. The 3D (r, v, v//) electron distribution function from CQL3D has been used in synthetic diagnostic codes to simulate the measured hard x-ray and ECE emissions. Fast electron diffusion times have been inferred from x-ray data by employing a radial diffusion operator in CQL3D and determining the fast electron diffusivities that are required to reproduce the experimentally observed profiles of hard x-ray emission. Finally, we have been performing full-wave LH field simulations using the massively parallel TORIC --LH solver [3] in order to assess spatial and spectral broadening of the incident wave front that can result from diffraction and wave focusing effects. [1] R. Parker, Bull. Am. Phys. Soc. 51, 20 (2006). [2] R.W. Harvey and M. McCoy, ``The CQL3D Fokker Planck Code,'' Proc. IAEA Tech. Comm. Meeting on Simulation and Modeling of Thermonuclear Plasmas, Montreal, Canada, 1992. [3] J. C. Wright et al., Nucl. Fusion 45, 1411 (2005).

  12. UPQC Controlled Capable Of Mitigating Unbalance In Source Voltage And Load Current

    Directory of Open Access Journals (Sweden)

    B. Santhosh Kumar

    2013-11-01

    Full Text Available This paper reports the development of a laboratory prototype of a fully digital DSP-controlled 12-kVA unified power quality conditioner (UPQC, capable of compensating for both the supply voltage and the load current imperfections. A fully digital controller based on the TMS320F2812 DSP platform is implemented for the reference generation as well as control purposes. The delay problem in the digital controller is overcome by application of a fast DSP, a compact control technique and proper flow of control steps in the DSP software. A phase-locked loop- less software grid synchronization method has been implemented for the effective operation of the UPQC under conditions of grid frequency variation. A sequence-based compensation strategy has been developed to compensate for balanced and unbalanced sags while accommodating the fact that the voltage injection capability of the UPQC is limited. The prototype UPQC power circuit, control features, and control algorithm along with experimental results are presented in this paper.

  13. Liquid nitrogen cooled integrated power electronics module with high current carrying capability and lower on resistance

    Science.gov (United States)

    Ye, Hua; Lee, Changwoo; Simon, Randy W.; Haldar, Pradeep; Hennessy, Michael J.; Mueller, Eduard K.

    2006-11-01

    This letter presents the development of high-performance integrated cryogenic power modules, where both driver components and power metal-oxide semiconductor field-effect transistors are integrated in a single package, to be used in a 50kW prototype cryogenic inverter operating at liquid nitrogen temperature. The authors have demonstrated a compact high-voltage, cryogenic integrated power module that exhibited more than 14 times improvement in on-resistance and continuous current carrying capability exceeding 40A. The modules are designed to operate at liquid nitrogen temperature with extreme thermal cycling. The power electronic modules are necessary components that provide control and switching for second generation, yttrium barium copper oxide-based high temperature superconductor devices including cables, motors, and generators.

  14. Dark Current and Multipacting Capabilities in OPAL: Model Benchmarks and Applications

    CERN Document Server

    Wang, C; Yin, Z G; Zhang, T J

    2012-01-01

    Dark current and multiple electron impacts (multipacting), as for example observed in radio frequency (RF) structures of accelerators, are usually harmful to the equipment and the beam quality. These effects need to be suppressed to guarantee efficient and stable operation. Large scale simulations can be used to understand causes and develop strategies to suppress these phenomenas. We extend \\opal, a parallel framework for charged particle optics in accelerator structures and beam lines, with the necessary physics models to efficiently and precisely simulate multipacting phenomenas. We added a Fowler-Nordheim field emission model, two secondary electron emission models, developed by Furman-Pivi and Vaughan respectively, as well as efficient 3D boundary geometry handling capabilities. The models and their implementation are carefully benchmark against a non-stationary multipacting theory for the classic parallel plate geometry. A dedicated, parallel plate experiment is sketched.

  15. Space Weather - Current Capabilities, Future Requirements, and the Path to Improved Forecasting

    Science.gov (United States)

    Mann, Ian

    2016-07-01

    We present an overview of Space Weather activities and future opportunities including assessments of current status and capabilities, knowledge gaps, and future directions in relation to both observations and modeling. The review includes input from the scientific community including from SCOSTEP scientific discipline representatives (SDRs), COSPAR Main Scientific Organizers (MSOs), and SCOSTEP/VarSITI leaders. The presentation also draws on results from the recent activities related to the production of the COSPAR-ILWS Space Weather Roadmap "Understanding Space Weather to Shield Society" [Schrijver et al., Advances in Space Research 55, 2745 (2015) http://dx.doi.org/10.1016/j.asr.2015.03.023], from the activities related to the United Nations (UN) Committee on the Peaceful Uses of Outer Space (COPUOS) actions in relation to the Long-term Sustainability of Outer Space (LTS), and most recently from the newly formed and ongoing efforts of the UN COPUOS Expert Group on Space Weather.

  16. Evolution of Wave Energy Deposition Profile in HT-7 Lower Hybrid Current Drive Experiment

    Institute of Scientific and Technical Information of China (English)

    方瑜德; 石跃江; 匡光力; 刘岳修; 沈慰慈; 丁伯江

    2001-01-01

    Lower hybrid waves (LHWs) with a selected n‖ spectrum have been used to control the energy deposition profiles, and then the wave driven current profiles effectively in tokamak discharges. In our lower hybrid current drive experiment in the HT-7 tokamak, it was found that the set-up of the wave energy deposition profile is a graduation process. In the beginning phase of the wave injection duration, the waves (with different n‖ spectra)deposit almost all their energy in the central region of the plasma column, even if their n‖ are very different. Up to around one hundred milliseconds, the wave energy deposition profiles can only take their corresponding shapes according to the n‖ spectra of LHWs. It also shown that this evolution process is affected obviously by the LHW driven current profile, which has been formed early.

  17. High voltage power supplies for ITER RF heating and current drive systems

    Energy Technology Data Exchange (ETDEWEB)

    Gassmann, T., E-mail: thibault.gassmann@iter.org [ITER Organization, CS 90 046, 13067 St. Paul Lez Durance Cedex (France); Arambhadiya, B.; Beaumont, B. [ITER Organization, CS 90 046, 13067 St. Paul Lez Durance Cedex (France); Baruah, U.K. [Institute for Plasma Research, Near Indira Bridge, Bhat, Gandhinagar 382428 (India); Bonicelli, T. [Fusion For Energy, C/3 Josep Pla 2, Torres Diagonal Litoral-B3, E-08019 Barcelona (Spain); Darbos, C.; Purohit, D.; Decamps, H. [ITER Organization, CS 90 046, 13067 St. Paul Lez Durance Cedex (France); Albajar, F. [Fusion For Energy, C/3 Josep Pla 2, Torres Diagonal Litoral-B3, E-08019 Barcelona (Spain); Gandini, F.; Henderson, M.; Kazarian, F.; Lamalle, P.U.; Omori, T. [ITER Organization, CS 90 046, 13067 St. Paul Lez Durance Cedex (France); Parmar, D.; Patel, A. [Institute for Plasma Research, Near Indira Bridge, Bhat, Gandhinagar 382428 (India); Rathi, D. [ITER Organization, CS 90 046, 13067 St. Paul Lez Durance Cedex (France); Singh, N.P. [Institute for Plasma Research, Near Indira Bridge, Bhat, Gandhinagar 382428 (India)

    2011-10-15

    The RF heating and current drive (H and CD) systems to be installed for the ITER fusion machine are the electron cyclotron (EC), ion cyclotron (IC) and, although not in the first phase of the project, lower hybrid (LH). These systems require high voltage, high current power supplies (HVPS) in CW operation. These HVPS should deliver around 50 MW electrical power to each of the RF H and CD systems with stringent requirements in terms of accuracy, voltage ripple, response time, turn off time and fault energy. The PSM (Pulse Step Modulation) technology has demonstrated over the past 20 years its ability to fulfill these requirements in many industrial facilities and other fusion reactors and has therefore been chosen as reference design for the IC and EC HVPS systems. This paper describes the technical specifications, including interfaces, the resulting constraints on the design, the conceptual design proposed for ITER EC and IC HVPS systems and the current status.

  18. Current drive with combined electron cyclotron wave and high harmonic fast wave in tokamak plasmas

    Science.gov (United States)

    Li, J. C.; Gong, X. Y.; Dong, J. Q.; Wang, J.; Zhang, N.; Zheng, P. W.; Yin, C. Y.

    2016-12-01

    The current driven by combined electron cyclotron wave (ECW) and high harmonic fast wave is investigated using the GENRAY/CQL3D package. It is shown that no significant synergetic current is found in a range of cases with a combined ECW and fast wave (FW). This result is consistent with a previous study [Harvey et al., in Proceedings of IAEA TCM on Fast Wave Current Drive in Reactor Scale Tokamaks (Synergy and Complimentarily with LHCD and ECRH), Arles, France, IAEA, Vienna, 1991]. However, a positive synergy effect does appear with the FW in the lower hybrid range of frequencies. This positive synergy effect can be explained using a picture of the electron distribution function induced by the ECW and a very high harmonic fast wave (helicon). The dependence of the synergy effect on the radial position of the power deposition, the wave power, the wave frequency, and the parallel refractive index is also analyzed, both numerically and physically.

  19. Reduced Order Models of a Current Source Inverter Induction Motor Drive

    Directory of Open Access Journals (Sweden)

    Ibrahim K. Al-Abbas

    2009-01-01

    Full Text Available Problem Statement: The current source inverter induction motor (CSI-IM drive was widely used in various industries. The main disadvantage of this drive was nonlinearity and complexity. This work was done to develop a simple drive systems models. Approach: The MATLAB/SIMULINK software was used for system modeling. Three reduced models were developed by choosing specific frame, neglecting stator transients and ignoring stator equations. Results: The dynamic performance of the models was examined in open loop form for a step change in control variable (the input voltage as well as for step change in disturbance (mechanical load.Conclusion: The three models were equivalent in steady state. The error of these models in the transient response was less than 5 %, with the exception of the time performances of the transient model to step change of supply voltage. Recommendations: All three models were suggested to be used for designing torque control systems. The detailed and stator equation models were recommended to be used in speed control design.

  20. High efficiency off-axis current drive by high frequency fast waves

    Energy Technology Data Exchange (ETDEWEB)

    Prater, R.; Pinsker, R. I.; Moeller, C. P. [General Atomics, PO Box 85608, San Diego, California 92186-5608 (United States); Porkolab, M.; Vdovin, V. [Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge, Massachusetts 02139 (United States)

    2014-02-12

    Modeling work shows that current drive can be done off-axis with high efficiency, as required for FNSF and DEMO, by using very high harmonic fast waves (“helicons” or “whistlers”). The modeling indicates that plasmas with high electron beta are needed in order for the current drive to take place off-axis, making DIII-D a highly suitable test vehicle for this process. The calculations show that the driven current is not very sensitive to the launched value of n{sub ∥}, a result that can be understood from examination of the evolution of n{sub ∥} as the waves propagate in the plasma. Because of this insensitivity, relatively large values (∼3) of n{sub ∥} can be launched, thereby avoiding some of the problems with mode conversion in the boundary found in some previous experiments. Use of a traveling wave antenna provides a very narrow n{sub ∥} spectrum, which also helps avoid mode conversion.

  1. The targeted heating and current drive applications for the ITER electron cyclotron system

    Energy Technology Data Exchange (ETDEWEB)

    Henderson, M.; Darbos, C.; Gandini, F.; Gassmann, T.; Loarte, A.; Omori, T.; Purohit, D. [ITER Organization, Route de Vinon-sur-Verdon, CS 90 046, 13067 St. Paul Lez Durance Cedex (France); Saibene, G.; Gagliardi, M. [Fusion for Energy, Josep Pla 2, Barcelona 08019 (Spain); Farina, D.; Figini, L. [Istituto di Fisica del Plasma CNR, 20125 Milano (Italy); Hanson, G. [US ITER Project Office, ORNL, 1055 Commerce Park, PO Box 2008, Oak Ridge, Tennessee 37831 (United States); Poli, E. [Max-Planck-Institut für Plasmaphysik, D-85748 Garching (Germany); Takahashi, K. [Japan Atomic Energy Agency (JAEA), Naka, Ibaraki 311-0193 (Japan)

    2015-02-15

    A 24 MW Electron Cyclotron (EC) system operating at 170 GHz and 3600 s pulse length is to be installed on ITER. The EC plant shall deliver 20 MW of this power to the plasma for Heating and Current Drive (H and CD) applications. The EC system is designed for plasma initiation, central heating, current drive, current profile tailoring, and Magneto-hydrodynamic control (in particular, sawteeth and Neo-classical Tearing Mode) in the flat-top phase of the plasma. A preliminary design review was performed in 2012, which identified a need for extended application of the EC system to the plasma ramp-up, flattop, and ramp down phases of ITER plasma pulse. The various functionalities are prioritized based on those applications, which can be uniquely addressed with the EC system in contrast to other H and CD systems. An initial attempt has been developed at prioritizing the allocated H and CD applications for the three scenarios envisioned: ELMy H-mode (15 MA), Hybrid (∼12 MA), and Advanced (∼9 MA) scenarios. This leads to the finalization of the design requirements for the EC sub-systems.

  2. Reduction of current chopping noise with DSP controller in switched reluctance motor drive system

    Institute of Scientific and Technical Information of China (English)

    郭伟; 詹琼华; 马志源

    2002-01-01

    A novel current chopping mode was used in a switched reluctance motor drive system to make full use of the characteristics of digital signal processor (DSP) TMS320F240. The necessity of this 180° phase-shift current control (PSCC) mode is introduced first and then the principle of PSCC covering both hardware requirement and software programming is described in detail. The analysis made indicated that with this mode, the chopping frequency in winding can reach 20 kHz with 10 kHz power switches and the control frequency can reach 40 kHz at the same time. Subsequently, based on the linear and nonlinear mathematical models of the switched reluctance motor ( SRM), some simulation work has been done. The simulation results show that when this mode is applied to SRM drive (SRD) system, the current waveform becomes better. So the ripple of the torque is reduced simultaneously and the vibration and acoustic noise are reduced involuntarily. Stationary tests show that the acoustic noise is greatly diminished. Finally, some experiments were made using a 50 kW SRD system for electric vehicle (EV). Experimental results indicate that this mode can be implemented feasibly and it has a good action on the SRD system.

  3. Destabilization of fast particle stabilized sawteeth in ASDEX Upgrade with electron cyclotron current drive

    DEFF Research Database (Denmark)

    Igochine, V.; Chapman, I.T.; Bobkov, V.

    2011-01-01

    It is often observed that large sawteeth trigger the neoclassical tearing mode well below the usual threshold for this instability. At the same time, fast particles in the plasma core stabilize sawteeth and provide these large crashes. The paper presents results of first experiments in ASDEX...... Upgrade for destabilization of fast particle stabilized sawteeth with electron cyclotron current drive (ECCD). It is shown that moderate ECCD from a single gyrotron is able to destabilize the fast particle stabilized sawteeth. A reduction in sawtooth period by about 40% was achieved in first experiments...

  4. Effect of Alfvén resonance on low-frequency fast wave current drive

    Science.gov (United States)

    Wang, C. Y.; Batchelor, D. B.; Carter, M. D.; Jaeger, E. F.; Stallings, D. C.

    1995-08-01

    The Alfvén resonances may occur on the low- and high-field sides for a low-frequency fast wave current drive scenario proposed for the International Thermonuclear Experimental Reactor (ITER) [Nucl. Fusion 31, 1135 (1991)]. At the resonance on the low-field side, the fast wave may be mode converted into a short-wavelength slow wave, which can be absorbed by electrons at the plasma edge, before the fast wave propagates into the core area of the plasma. Such absorption may cause a significant parasitic power loss.

  5. Effect of Alfven resonance on low-frequency fast wave current drive

    Energy Technology Data Exchange (ETDEWEB)

    Wang, C.Y.; Batchelor, D.B.; Carter, M.D.; Jaeger, E.F.; Stallings, D.C. [Fusion Energy Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)

    1995-07-01

    The Alfven resonances may occur on the low- and high-field sides for a low-frequency fast wave current drive scenario proposed for the International Thermonuclear Experimental Reactor (ITER) [Nucl. Fusion {bold 31}, 1135 (1991)]. At the resonance on the low-field side, the fast wave may be mode converted into a short-wavelength slow wave, which can be absorbed by electrons at the plasma edge, before the fast wave propagates into the core area of the plasma. Such absorption may cause a significant parasitic power loss. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.

  6. Effects of electron cyclotron current drive on the evolution of double tearing mode

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Guanglan, E-mail: sunguanglan@nciae.edu.cn; Dong, Chunying [Basic Science Section, North China Institute of Aerospace Engineering, Langfang 065000 (China); Duan, Longfang [School of Computer and Remote Sensing Information Technology, North China Institute of Aerospace Engineering, Langfang 065000 (China)

    2015-09-15

    The effects of electron cyclotron current drive (ECCD) on the double tearing mode (DTM) in slab geometry are investigated by using two-dimensional compressible magnetohydrodynamics equations. It is found that, mainly, the double tearing mode is suppressed by the emergence of the secondary island, due to the deposition of driven current on the X-point of magnetic island at one rational surface, which forms a new non-complete symmetric magnetic topology structure (defined as a non-complete symmetric structure, NSS). The effects of driven current with different parameters (magnitude, initial time of deposition, duration time, and location of deposition) on the evolution of DTM are analyzed elaborately. The optimal magnitude or optimal deposition duration of driven current is the one which makes the duration of NSS the longest, which depends on the mutual effect between ECCD and the background plasma. Moreover, driven current introduced at the early Sweet-Parker phase has the best suppression effect; and the optimal moment also exists, depending on the duration of the NSS. Finally, the effects varied by the driven current disposition location are studied. It is verified that the favorable location of driven current is the X-point which is completely different from the result of single tearing mode.

  7. A fresh look at electron cyclotron current drive power requirements for stabilization of tearing modes in ITER

    Energy Technology Data Exchange (ETDEWEB)

    La Haye, R. J., E-mail: lahaye@fusion.gat.com [General Atomics, P.O. Box 85608, San Diego, California 92186-5608 (United States)

    2015-12-10

    ITER is an international project to design and build an experimental fusion reactor based on the “tokamak” concept. ITER relies upon localized electron cyclotron current drive (ECCD) at the rational safety factor q=2 to suppress or stabilize the expected poloidal mode m=2, toroidal mode n=1 neoclassical tearing mode (NTM) islands. Such islands if unmitigated degrade energy confinement, lock to the resistive wall (stop rotating), cause loss of “H-mode” and induce disruption. The International Tokamak Physics Activity (ITPA) on MHD, Disruptions and Magnetic Control joint experiment group MDC-8 on Current Drive Prevention/Stabilization of Neoclassical Tearing Modes started in 2005, after which assessments were made for the requirements for ECCD needed in ITER, particularly that of rf power and alignment on q=2 [1]. Narrow well-aligned rf current parallel to and of order of one percent of the total plasma current is needed to replace the “missing” current in the island O-points and heal or preempt (avoid destabilization by applying ECCD on q=2 in absence of the mode) the island [2-4]. This paper updates the advances in ECCD stabilization on NTMs learned in DIII-D experiments and modeling during the last 5 to 10 years as applies to stabilization by localized ECCD of tearing modes in ITER. This includes the ECCD (inside the q=1 radius) stabilization of the NTM “seeding” instability known as sawteeth (m/n=1/1) [5]. Recent measurements in DIII-D show that the ITER-similar current profile is classically unstable, curvature stabilization must not be neglected, and the small island width stabilization effect from helical ion polarization currents is stronger than was previously thought [6]. The consequences of updated assumptions in ITER modeling of the minimum well-aligned ECCD power needed are all-in-all favorable (and well-within the ITER 24 gyrotron capability) when all effects are included. However, a “wild card” may be broadening of the localized

  8. A fresh look at electron cyclotron current drive power requirements for stabilization of tearing modes in ITER

    Science.gov (United States)

    La Haye, R. J.

    2015-12-01

    ITER is an international project to design and build an experimental fusion reactor based on the "tokamak" concept. ITER relies upon localized electron cyclotron current drive (ECCD) at the rational safety factor q=2 to suppress or stabilize the expected poloidal mode m=2, toroidal mode n=1 neoclassical tearing mode (NTM) islands. Such islands if unmitigated degrade energy confinement, lock to the resistive wall (stop rotating), cause loss of "H-mode" and induce disruption. The International Tokamak Physics Activity (ITPA) on MHD, Disruptions and Magnetic Control joint experiment group MDC-8 on Current Drive Prevention/Stabilization of Neoclassical Tearing Modes started in 2005, after which assessments were made for the requirements for ECCD needed in ITER, particularly that of rf power and alignment on q=2 [1]. Narrow well-aligned rf current parallel to and of order of one percent of the total plasma current is needed to replace the "missing" current in the island O-points and heal or preempt (avoid destabilization by applying ECCD on q=2 in absence of the mode) the island [2-4]. This paper updates the advances in ECCD stabilization on NTMs learned in DIII-D experiments and modeling during the last 5 to 10 years as applies to stabilization by localized ECCD of tearing modes in ITER. This includes the ECCD (inside the q=1 radius) stabilization of the NTM "seeding" instability known as sawteeth (m/n=1/1) [5]. Recent measurements in DIII-D show that the ITER-similar current profile is classically unstable, curvature stabilization must not be neglected, and the small island width stabilization effect from helical ion polarization currents is stronger than was previously thought [6]. The consequences of updated assumptions in ITER modeling of the minimum well-aligned ECCD power needed are all-in-all favorable (and well-within the ITER 24 gyrotron capability) when all effects are included. However, a "wild card" may be broadening of the localized ECCD by the presence of

  9. SOL plasma measurements during high density and long duration current drive on TRIAM-1M

    Energy Technology Data Exchange (ETDEWEB)

    Takemura, Takeharu; Kawasaki, Shoji; Jotaki, Eriko; Makino, Ken-ichi; Sakamoto, Mizuki; Nakamura, Kazuo; Nakamura, Yukio; Itoh, Sanae; Itoh, Satoshi [Kyushu Univ., Kasuga, Fukuoka (Japan). Research Inst. for Applied Mechanics

    1997-02-01

    In the superconducting, strong magnetic field tokamak, TRIAM-1M, for the purpose of maintaining high density plasma for long time, the current drive experiment using 8.2 GHz lower hybrid wave has been carried out. For maintaining high density plasma for long time, it is indispensable to control gas puff and recycling from wall, as these are closely related to the structure and characteristics of boundary plasma including scrape-off layer (SOL). In this study, in the high density, long time current drive using 8.2 GHz lower hybrid wave, the electron density and electron temperature of SOL plasma were measured by using double probe, and the z-direction distribution and the toroidal magnetic field dependence of the electron density and electron temperature of SOL plasma were examined and compared with OH discharge. Also the dependence of the electron density of SOL plasma on the phase difference in a adjoining waveguide tubes was examined. The experimental setup and the double probe theory are explained. The experimental results of the change with time lapse, the z-direction distribution and the magnetic field dependence of the electron density and electron temperature of SOL plasma are reported. (K.I.)

  10. Performance Evaluation of Electronic Inductor-Based Adjustable Speed Drives with Respect to Line Current Interharmonics

    DEFF Research Database (Denmark)

    Soltani, Hamid; Davari, Pooya; Blaabjerg, Frede

    2017-01-01

    Electronic Inductor (EI)-based front-end rectifiers have a large potential to become the prominent next generation of Active Front End (AFE) topology used in many applications including Adjustable Speed Drives (ASDs) for systems having unidirectional power flow. The EI-based ASD is mostly...... attractive due to its improved harmonic performance compared to a conventional ASD. In this digest, the input currents of the EI-based ASD are investigated and compared with the conventional ASDs with respect to interharmonics, which is an emerging power quality topic. First, the main causes...... of the interharmonic distortions in the ASD applications are analyzed under balanced and unbalanced load conditions. Thereafter, the key role of the EI at the DC stage is investigated in terms of high impedance and current harmonics transfer. Obtained experiments and simulations for both EI-based and conventional ASD...

  11. Ion cyclotron and lower hybrid arrays applicable to current drive in fusion reactors

    Science.gov (United States)

    Bosia, G.; Helou, W.; Goniche, M.; Hillaret, J.; Ragona, R.

    2014-02-01

    This paper presents concepts for Ion Cyclotron and Lower Hybrid Current Drive arrays applicable to fusion reactors and based on periodically loaded line power division. It is shown that, in large arrays, such as the ones proposed for fusion reactor applications, these schemes can offer, in principle, a number of practical advantages, compared with currently adopted ones, such as in-blanket operation at significantly reduced power density, lay out suitable for water cooling, single ended or balanced power feed, simple and load independent impedance matching In addition, a remote and accurate real time measurement of the complex impedance of all array elements as well as detection, location, and measurement of the complex admittance of a single arc occurring anywhere in the structure is possible.

  12. Ohmic Radio-Frequency Synergy Current Drive and Transformer Recharging Experiments in the HT-7 Tokamak

    Institute of Scientific and Technical Information of China (English)

    CHEN Zhong-Yong; WAN Bao-Nian; SHI Yue-Jiang; HU Li-Qun; XU Han-Dong

    2005-01-01

    @@ Lower hybrid current drive (LHCD) experiments for investigating the interaction between lower hybrid (LH) wave and residual dc electric field were performed in extensive plasma parameter ranges in the HT-7 superconducting tokamak. The experimental results are well fitted to the Karney-Fisch theory on the efficiency of LH waves energy converted to poloidal magnetic field energy. The fraction of absorbed LH power is about 0.75 for the HT-7 machine, and the upshift of the LH-wave parallel refraction index during LHCD experiments have been derived by the optimizing fitting parameters. The LH wave is also used for the transformer recharging when the plasma current is maintained unchanged. The highest efficiency about 7% has been achieved in HT-7 machine.

  13. Heating and current drive by fast wave in lower hybrid range of frequency on Versatile Experiment Spherical Torus

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sun-Ho, E-mail: shkim95@kaeri.re.kr [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Jeong, Seung-Ho [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Lee, Hyunwoo; Lee, Byungje [KwangWoon University, Seoul (Korea, Republic of); Jo, Jong-Gab; Lee, Hyun-Young; Hwang, Yong-Seok [Seoul National University, Seoul (Korea, Republic of)

    2016-11-01

    An efficient heating and current drive scheme in central or off-axis region is required to realize steady state operation of tokamak fusion reactor. And the fast wave in lower hybrid resonance range of frequency could be a candidate for such an efficient scheme in high density and high temperature plasmas. Its propagation and absorption characteristics including current drive and coupling efficiency are analyzed for Versatile Experiment Spherical Torus and it is shown that it is possible to drive current with considerable current drive efficiency in central region. The RF system for the fast wave experiment including klystron, transmission systems, inter-digital antenna, and RF diagnostics are given as well in this paper.

  14. Overview of current capabilities and research and technology developments for planetary protection

    Science.gov (United States)

    Frick, Andreas; Mogul, Rakesh; Stabekis, Pericles; Conley, Catharine A.; Ehrenfreund, Pascale

    2014-07-01

    The pace of scientific exploration of our solar system provides ever-increasing insights into potentially habitable environments, and associated concerns for their contamination by Earth organisms. Biological and organic-chemical contamination has been extensively considered by the COSPAR Panel on Planetary Protection (PPP) and has resulted in the internationally recognized regulations to which spacefaring nations adhere, and which have been in place for 40 years. The only successful Mars lander missions with system-level “sterilization” were the Viking landers in the 1970s. Since then different cleanliness requirements have been applied to spacecraft based on their destination, mission type, and scientific objectives. The Planetary Protection Subcommittee of the NASA Advisory Council has noted that a strategic Research & Technology Development (R&TD) roadmap would be very beneficial to encourage the timely availability of effective tools and methodologies to implement planetary protection requirements. New research avenues in planetary protection for ambitious future exploration missions can best be served by developing an over-arching program that integrates capability-driven developments with mission-driven implementation efforts. This paper analyzes the current status concerning microbial reduction and cleaning methods, recontamination control and bio-barriers, operational analysis methods, and addresses concepts for human exploration. Crosscutting research and support activities are discussed and a rationale for a Strategic Planetary Protection R&TD Roadmap is outlined. Such a roadmap for planetary protection provides a forum for strategic planning and will help to enable the next phases of solar system exploration.

  15. Arctic Observing Network Data Management: Current Capabilities and Their Promise for the Future

    Science.gov (United States)

    Collins, J.; Fetterer, F.; Moore, J. A.

    2008-12-01

    CADIS (the Cooperative Arctic Data and Information Service) serves as the data management, discovery and delivery component of the Arctic Observing Network (AON). As an International Polar Year (IPY) initiative, AON comprises 34 land, atmosphere and ocean observation sites, and will acquire much of the data coming from the interagency Study of Environmental Arctic Change (SEARCH). CADIS is tasked with ensuring that these observational data are managed for long term use by members of the entire Earth System Science community. Portions of CADIS are either in use by the community or available for testing. We now have an opportunity to evaluate the feedback received from our users, to identify any design shortcomings, and to identify those elements which serve their purpose well and will support future development. This presentation will focus on the nuts-and-bolts of the CADIS development to date, with an eye towards presenting lessons learned and best practices based on our experiences so far. The topics include: - How did we assess our users' needs, and how are those contributions reflected in the end product and its capabilities? - Why did we develop a CADIS metadata profile, and how does it allow CADIS to support preservation and scientific interoperability? - How can we shield the user from metadata complexities (especially those associated with various standards) while still obtaining the metadata needed to support an effective data management system? - How can we bridge the gap between the data storage formats considered convenient by researchers in the field, and those which are necessary to provide data interoperability? - What challenges have been encountered in our efforts to provide access to federated data (data stored outside of the CADIS system)? - What are the data browsing and visualization needs of the AON community, and which tools and technologies are most promising in terms of supporting those needs? A live demonstration of the current

  16. Controlling fluctuations and transport in the reversed field pinch with edge current drive and plasma biasing

    Energy Technology Data Exchange (ETDEWEB)

    Craig, D.J.G.

    1998-09-01

    Two techniques are employed in the Madison Symmetric Torus (MST) to test and control different aspects of fluctuation induced transport in the Reversed Field Pinch (RFP). Auxiliary edge currents are driven along the magnetic field to modify magnetic fluctuations, and the particle and energy transport associated with them. In addition, strong edge flows are produced by plasma biasing. Their effect on electrostatic fluctuations and the associated particle losses is studied. Both techniques are accomplished using miniature insertable plasma sources that are biased negatively to inject electrons. This type of emissive electrode is shown to reliably produce intense, directional current without significant contamination by impurities. The two most important conclusions derived from these studies are that the collective modes resonant at the reversal surface play a role in global plasma confinement, and that these modes can be controlled by modifying the parallel current profile outside of the reversal surface. This confirms predictions based on magnetohydrodynamic (MHD) simulations that auxiliary current drive in the sense to flatten the parallel current profile can be successful in controlling magnetic fluctuations in the RFP. However, these studies expand the group of magnetic modes believed to cause transport in MST and suggest that current profile control efforts need to address both the core resonant magnetic modes and those resonant at the reversal surface. The core resonant modes are not significantly altered in these experiments; however, the distribution and/or amplitude of the injected current is probably not optimal for affecting these modes. Plasma biasing generates strong edge flows with shear and particle confinement likely improves in these discharges. These experiments resemble biased H modes in other magnetic configurations in many ways. The similarities are likely due to the common role of electrostatic fluctuations in edge transport.

  17. Requirements on localized current drive for the suppression of neoclassical tearing modes

    Science.gov (United States)

    Bertelli, N.; De Lazzari, D.; Westerhof, E.

    2011-10-01

    A heuristic criterion for the full suppression of an NTM was formulated as ηNTM ≡ jCD,max/jBS >= 1.2 (Zohm et al 2005 J. Phys. Conf. Ser. 25 234), where jCD,max is the maximum in the driven current density profile applied to stabilize the mode and jBS is the local bootstrap current density. In this work we subject this criterion to a systematic theoretical analysis on the basis of the generalized Rutherford equation. Taking into account only the effect of jCD inside the island, a new criterion for full suppression by a minimum applied total current is obtained in the form of a maximum allowed value for the width of the driven current, wdep, combined with a required minimum for the total driven current in the form of wdepηNTM, where both limits depend on the marginal and saturated island sizes. These requirements can be relaxed when additional effects are taken into account, such as a change in the stability parameter Δ' from the current driven outside the island, power modulation, the accompanying heating inside the island or when the current drive is applied preemptively. When applied to ITER scenario 2, the requirement for full suppression of either the 3/2 or 2/1 NTM becomes wdep ~ 5 cm in agreement with (Sauter et al 2010 Plasma Phys. Control. Fusion 52 025002). Optimization of the ITER ECRH Upper Port Launcher design towards minimum required power for full NTM suppression requires an increase in the toroidal injection angle of the lower steering mirror of several degrees compared with its present design value, while for the upper steering mirror the present design value is close to the optimum.

  18. ADVANCED SIMULATION CAPABILITY FOR ENVIRONMENTAL MANAGEMENT- CURRENT STATUS AND PHASE II DEMONSTRATION RESULTS

    Energy Technology Data Exchange (ETDEWEB)

    Seitz, R.

    2013-02-26

    The U.S. Department of Energy (USDOE) Office of Environmental Management (EM), Office of Soil and Groundwater, is supporting development of the Advanced Simulation Capability for Environmental Management (ASCEM). ASCEM is a state-of-the-art scientific tool and approach for understanding and predicting contaminant fate and transport in natural and engineered systems. The modular and open source high-performance computing tool facilitates integrated approaches to modeling and site characterization that enable robust and standardized assessments of performance and risk for EM cleanup and closure activities. The ASCEM project continues to make significant progress in development of computer software capabilities with an emphasis on integration of capabilities in FY12. Capability development is occurring for both the Platform and Integrated Toolsets and High-Performance Computing (HPC) Multiprocess Simulator. The Platform capabilities provide the user interface and tools for end-to-end model development, starting with definition of the conceptual model, management of data for model input, model calibration and uncertainty analysis, and processing of model output, including visualization. The HPC capabilities target increased functionality of process model representations, toolsets for interaction with Platform, and verification and model confidence testing. The Platform and HPC capabilities are being tested and evaluated for EM applications in a set of demonstrations as part of Site Applications Thrust Area activities. The Phase I demonstration focusing on individual capabilities of the initial toolsets was completed in 2010. The Phase II demonstration completed in 2012 focused on showcasing integrated ASCEM capabilities. For Phase II, the Hanford Site deep vadose zone (BC Cribs) served as an application site for an end-to-end demonstration of capabilities, with emphasis on integration and linkages between the Platform and HPC components. Other demonstrations

  19. Odour-tracking capability of a silkmoth driving a mobile robot with turning bias and time delay.

    Science.gov (United States)

    Ando, N; Emoto, S; Kanzaki, R

    2013-03-01

    The reconstruction of mechanisms behind odour-tracking behaviours of animals is expected to enable the development of biomimetic robots capable of adaptive behaviour and effectively locating odour sources. However, because the behavioural mechanisms of animals have not been extensively studied, their behavioural capabilities cannot be verified. In this study, we have employed a mobile robot driven by a genuine insect (insect-controlled robot) to evaluate the behavioural capabilities of a biological system implemented in an artificial system. We used a male silkmoth as the 'driver' and investigated its behavioural capabilities to imposed perturbations during odour tracking. When we manipulated the robot to induce the turning bias, it located the odour source by compensatory turning of the on-board moth. Shifting of the orientation paths to the odour plume boundaries and decreased orientation ability caused by covering the visual field suggested that the moth steered with bilateral olfaction and vision to overcome the bias. An evaluation of the time delays of the moth and robot movements suggested an acceptable range for sensory-motor processing when the insect system was directly applied to artificial systems. Further evaluations of the insect-controlled robot will provide a 'blueprint' for biomimetic robots and strongly promote the field of biomimetics.

  20. Status of the ITER Electron Cyclotron Heating and Current Drive System

    Science.gov (United States)

    Darbos, Caroline; Albajar, Ferran; Bonicelli, Tullio; Carannante, Giuseppe; Cavinato, Mario; Cismondi, Fabio; Denisov, Grigory; Farina, Daniela; Gagliardi, Mario; Gandini, Franco; Gassmann, Thibault; Goodman, Timothy; Hanson, Gregory; Henderson, Mark A.; Kajiwara, Ken; McElhaney, Karen; Nousiainen, Risto; Oda, Yasuhisa; Omori, Toshimichi; Oustinov, Alexander; Parmar, Darshankumar; Popov, Vladimir L.; Purohit, Dharmesh; Rao, Shambhu Laxmikanth; Rasmussen, David; Rathod, Vipal; Ronden, Dennis M. S.; Saibene, Gabriella; Sakamoto, Keishi; Sartori, Filippo; Scherer, Theo; Singh, Narinder Pal; Strauß, Dirk; Takahashi, Koji

    2016-01-01

    The electron cyclotron (EC) heating and current drive (H&CD) system developed for the ITER is made of 12 sets of high-voltage power supplies feeding 24 gyrotrons connected through 24 transmission lines (TL), to five launchers, four located in upper ports and one at the equatorial level. Nearly all procurements are in-kind, following general ITER philosophy, and will come from Europe, India, Japan, Russia and the USA. The full system is designed to couple to the plasma 20 MW among the 24 MW generated power, at the frequency of 170 GHz, for various physics applications such as plasma start-up, central H&CD and magnetohydrodynamic (MHD) activity control. The design takes present day technology and extends toward high-power continuous operation, which represents a large step forward as compared to the present state of the art. The ITER EC system will be a stepping stone to future EC systems for DEMO and beyond.

  1. Electron Cyclotron Current Drive at High Electron Temperature on DIII-D

    Science.gov (United States)

    Petty, C. C.; Austin, M. E.; Harvey, R. W.; Lohr, J.; Luce, T. C.; Makowski, M. A.; Prater, R.

    2007-09-01

    Experiments on DIII-D have measured the electron cyclotron current drive (ECCD) efficiency for co- and counter-injection in low density plasmas with radiation temperatures from electron cyclotron emission (ECE) above 20 keV. The radiation temperature is generally higher than the Thomson scattering temperature, indicating that there is a significant population of non-thermal electrons. The experimental ECCD profile measured with motional Stark effect (MSE) polarimetry is found to agree with quasi-linear theory except for the highest power density cases (QEC/ne2≫1). Radial transport of the energetic electrons with diffusion coefficients of ˜0.4 m2/s is needed to model the broadened ECCD profile at high power density.

  2. A Study on New Current Controller for 7-Phase BLDC Motor Drive System

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Surk; Jeon, Ywun Seok; Mok, Hyung Soo [Konkuk University (Korea); Kim, Duk Keun [Komotek Co., Ltd. (Korea)

    2001-04-01

    Recently, the demand of motor for industrial, household machinery is increasing. As Switching devices and control technology are progressing, so the use of BLDC Motor is increasing. But 3-phase BLCD Motor generally used has pulsating torque and speed variation in commutation, so the range of its application is limited to high speed operation. Especially, to solve these problems, it is necessary to increase phase of Motor, so study of Poly-Phase BLDC Motor is progressing. However, when hysteresis current controller is used, switching frequency is highly increasing. In this paper, 7-Phase BLDC Motor drive system is designed. Also MSTC (Minimum Switching Time Controller) is proposed and with simulation and experiment, their validities are verified. (author). 10 refs., 26 figs., 1 tab.

  3. The efficiency of fast wave current drive for a weakly relativistic plasma

    Science.gov (United States)

    Chiu, S. C.; Lin-Liu, Y. R.; Karney, C. F. F.

    1994-10-01

    Current drive by fast waves (FWCD) is an important candidate for steady-state operation of tokamaks. Major experiments using this scheme are being carried out on DIII-D. There has been considerable study of the theoretical efficiency of FWCD. In Refs. 4 and 5, the nonrelativistic efficiency of FWCD at arbitrary frequencies was studied. For DIII-D parameters, the results can be considerably different from the Landau and Alfvén limits. At the high temperatures of reactors and DIII-D upgrade, relativistic effects become important. In this paper, the relativistic FWCD efficiency for arbitrary frequencies is studied. Assuming that the plasma is weakly relativistic, i.e., Te/mc2 is small, an analytic expression for FWCD is obtained for high resonant energies (uph/uTe≫1). Comparisons with the results from a numerical code ADJ and the nonrelativistic results shall be made and analytical fits in the whole range of velocities shall be presented.

  4. HHFW Heating and Current Drive Studies of NSTX H-Mode Plasmas

    Energy Technology Data Exchange (ETDEWEB)

    G. Taylor, P.T. Bonoli, D.L. Green, R.W. Harvey, J.C. Hosea, E.F. Jaeger, B.P. LeBlanc, R. Maingi, C.K. Phillips, P.M. Ryan, E.J. Valeo, J.R. Wilson, J.C. Wright, and the NSTX Team

    2011-06-08

    30 MHz high-harmonic fast wave (HHFW) heating and current drive are being developed to assist fully non-inductive plasma current (I{sub p}) ramp-up in NSTX. The initial approach to achieving this goal has been to heat I{sub p} = 300 kA inductive plasmas with current drive antenna phasing in order to generate an HHFW H-mode with significant bootstrap and RF-driven current. Recent experiments, using only 1.4 MW of RF power (P{sub RF}), achieved a noninductive current fraction, f{sub NI} {approx} 0.65. Improved antenna conditioning resulted in the generation of I{sub p} = 650 kA HHFW H-mode plasmas, with f{sub NI} {approx} 0.35, when P{sub RF} {ge} 2.5 MW. These plasmas have little or no edge localized mode (ELM) activity during HHFW heating, a substantial increase in stored energy and a sustained central electron temperature of 5-6 keV. Another focus of NSTX HHFW research is to heat an H-mode generated by 90 keV neutral beam injection (NBI). Improved HHFW coupling to NBI-generated H-modes has resulted in a broad increase in electron temperature profile when HHFW heating is applied. Analysis of a closely matched pair of NBI and HHFW+NBI H-mode plasmas revealed that about half of the antenna power is deposited inside the last closed flux surface (LCFS). Of the power damped inside the LCFS about two-thirds is absorbed directly by electrons and one-third accelerates fast-ions that are mostly promptly lost from the plasma. At longer toroidal launch wavelengths, HHFW+NBI H-mode plasmas can have an RF power flow to the divertor outside the LCFS that significantly reduces RF power deposition to the core. ELMs can also reduce RF power deposition to the core and increase power deposition to the edge. Recent full wave modeling of NSTX HHFW+NBI H-mode plasmas, with the model extended to the vessel wall, predicts a coaxial standing mode between the LCFS and the wall that can have large amplitudes at longer launch wavelengths. These simulation results qualitatively agree with HHFW

  5. Tomography of the fast electron Bremsstrahlung emission during lower hybrid current drive on Tore Supra

    Energy Technology Data Exchange (ETDEWEB)

    Peysson, Y.; Imbeaux, F. [Association Euratom-CEA, CEA/Cadarache, Dept. de Recherches sur la Fusion Controlee (DRFC), 13 - Saint-Paul-lez-Durance (France)

    1999-04-01

    A new tomography dedicated to detailed studies of the fast electron Bremsstrahlung emission in the hard X-ray (HXR) energy range between 20 and 200 keV during lower hybrid (LH) current drive experiments on the TORE SUPRA tokamak [Equipe TORE SUPRA, in Proceedings of the 15. Conference on Plasma Physics and Controlled Nuclear Fusion Research, Seville (International Atomic Energy Agency, Vienna, 1995), 1, AIEA-CN-60 / A1-5, p. 105] is presented. Radiation detection is performed by cadmium telluride(CdTe) semiconductors, which have most of the desirable features for a powerful diagnosing of magnetically confined hot plasmas - compact size, high X-ray stopping efficiency, fast timing characteristics, good energy resolution, no sensitivity to magnetic field, reasonable susceptibility to performance degradation from neutron/{gamma}-induced damages. This instrument is made of two independent cameras viewing a poloidal cross-section of the plasma, with respectively 21 and 38 detectors. A coarse spectrometry - 8 energy channels - is carried out for each chord, with an energy resolution of 20 keV. The spatial resolution in the core of the plasma is 4-5 cm, while the time sampling may be lowered down to of 2-4 ms. Powerful inversion techniques based on maximum entropy or regularization algorithms take fully advantage of the large number of line-integrated measurements for very robust estimates of the local HXR profiles as a function of time and photon energy. A detailed account of main characteristics and performances of the diagnostic is reported as well as preliminary results on LH current drive experiments. (authors)

  6. A DEMO relevant fast wave current drive high harmonic antenna exploiting the high impedance technique

    Science.gov (United States)

    Milanesio, D.; Maggiora, R.

    2015-12-01

    Ion Cyclotron (IC) antennas are routinely adopted in most of the existing nuclear fusion experiments, even though their main goal, i.e. to couple high power to the plasma (MW), is often limited by rather severe drawbacks due to high fields on the antenna itself and on the unmatched part of the feeding lines. In addition to the well exploited auxiliary ion heating during the start-up phase, some non-ohmic current drive (CD) at the IC range of frequencies may be explored in view of the DEMO reactor. In this work, we suggest and describe a compact high frequency DEMO relevant antenna, based on the high impedance surfaces concept. High-impedance surfaces are periodic metallic structures (patches) usually displaced on top of a dielectric substrate and grounded by means of vertical posts embedded inside the dielectric, in a mushroom-like shape. These structures present a high impedance, within a given frequency band, such that the image currents are in-phase with the currents of the antenna itself, thus determining a significant efficiency increase. After a general introduction on the properties of high impedance surfaces, we analyze, by means of numerical codes, a dielectric based and a full metal solution optimized to be tested and benchmarked on the FTU experiment fed with generators at 433MHz.

  7. A DEMO relevant fast wave current drive high harmonic antenna exploiting the high impedance technique

    Energy Technology Data Exchange (ETDEWEB)

    Milanesio, D., E-mail: daniele.milanesio@polito.it; Maggiora, R. [Politecnico di Torino, Dipartimento di Elettronica e Telecomunicazioni (DET), Torino (Italy)

    2015-12-10

    Ion Cyclotron (IC) antennas are routinely adopted in most of the existing nuclear fusion experiments, even though their main goal, i.e. to couple high power to the plasma (MW), is often limited by rather severe drawbacks due to high fields on the antenna itself and on the unmatched part of the feeding lines. In addition to the well exploited auxiliary ion heating during the start-up phase, some non-ohmic current drive (CD) at the IC range of frequencies may be explored in view of the DEMO reactor. In this work, we suggest and describe a compact high frequency DEMO relevant antenna, based on the high impedance surfaces concept. High-impedance surfaces are periodic metallic structures (patches) usually displaced on top of a dielectric substrate and grounded by means of vertical posts embedded inside the dielectric, in a mushroom-like shape. These structures present a high impedance, within a given frequency band, such that the image currents are in-phase with the currents of the antenna itself, thus determining a significant efficiency increase. After a general introduction on the properties of high impedance surfaces, we analyze, by means of numerical codes, a dielectric based and a full metal solution optimized to be tested and benchmarked on the FTU experiment fed with generators at 433MHz.

  8. Fault diagnosis of motor drives using stator current signal analysis based on dynamic time warping

    Science.gov (United States)

    Zhen, D.; Wang, T.; Gu, F.; Ball, A. D.

    2013-01-01

    Electrical motor stator current signals have been widely used to monitor the condition of induction machines and their downstream mechanical equipment. The key technique used for current signal analysis is based on Fourier transform (FT) to extract weak fault sideband components from signals predominated with supply frequency component and its higher order harmonics. However, the FT based method has limitations such as spectral leakage and aliasing, leading to significant errors in estimating the sideband components. Therefore, this paper presents the use of dynamic time warping (DTW) to process the motor current signals for detecting and quantifying common faults in a downstream two-stage reciprocating compressor. DTW is a time domain based method and its algorithm is simple and easy to be embedded into real-time devices. In this study DTW is used to suppress the supply frequency component and highlight the sideband components based on the introduction of a reference signal which has the same frequency component as that of the supply power. Moreover, a sliding window is designed to process the raw signal using DTW frame by frame for effective calculation. Based on the proposed method, the stator current signals measured from the compressor induced with different common faults and under different loads are analysed for fault diagnosis. Results show that DTW based on residual signal analysis through the introduction of a reference signal allows the supply components to be suppressed well so that the fault related sideband components are highlighted for obtaining accurate fault detection and diagnosis results. In particular, the root mean square (RMS) values of the residual signal can indicate the differences between the healthy case and different faults under varying discharge pressures. It provides an effective and easy approach to the analysis of motor current signals for better fault diagnosis of the downstream mechanical equipment of motor drives in the time

  9. Principal physics of rotating magnetic-field current drive of field reversed configurations

    Science.gov (United States)

    Hoffman, A. L.; Guo, H. Y.; Miller, K. E.; Milroy, R. D.

    2006-01-01

    After extensive experimentation on the Translation, Confinement, and Sustainment rotating magnetic-field (RMF)-driven field reversed configuration (FRC) device [A. L. Hoffman et al., Fusion Sci. Technol. 41, 92 (2002)], the principal physics of RMF formation and sustainment of standard prolate FRCs inside a flux conserver is reasonably well understood. If the RMF magnitude Bω at a given frequency ω is high enough compared to other experimental parameters, it will drive the outer electrons of a plasma column into near synchronous rotation, allowing the RMF to penetrate into the plasma. If the resultant azimuthal current is strong enough to reverse an initial axial bias field Bo a FRC will be formed. A balance between the RMF applied torque and electron-ion friction will determine the peak plasma density nm∝Bω/η1/2ω1/2rs, where rs is the FRC separatrix radius and η is an effective weighted plasma resistivity. The plasma total temperature Tt is free to be any value allowed by power balance as long as the ratio of FRC diamagnetic current, I'dia≈2Be/μo, is less than the maximum possible synchronous current, I'sync=⟨ne⟩eωrs2/2. The RMF will self-consistently penetrate a distance δ* governed by the ratio ζ =I'dia/I'sync. Since the FRC is a diamagnetic entity, its peak pressure pm=nmkTt determines its external magnetic field Be≈(2μopm)1/2. Higher FRC currents, magnetic fields, and poloidal fluxes can thus be obtained, with the same RMF parameters, simply by raising the plasma temperature. Higher temperatures have also been noted to reduce the effective plasma resistivity, so that these higher currents can be supported with surprisingly little increase in absorbed RMF power.

  10. The SCEC Community Modeling Environment (SCEC/CME) - An Overview of its Architecture and Current Capabilities

    Science.gov (United States)

    Maechling, P. J.; Jordan, T. H.; Minster, B.; Moore, R.; Kesselman, C.; SCEC ITR Collaboration

    2004-12-01

    these models. In some cases, the CME system also provides alternatives to the SCEC community models. The CME system hosts a collection of community geophysical software codes. These codes include seismic hazard analysis (SHA) programs developed by the SCEC/USGS OpenSHA group. Also, the CME system hosts anelastic wave propagation codes including Kim Olsen's Finite Difference code and Carnegie Mellon's Hercules Finite Element tool chain. The CME system can execute a workflow, that is, a series of geophysical computations using the output of one processing step as the input to a subsequent step. Our workflow capability utilizes grid-based computing software that can submit calculations to a pool of computing resources as well as data management tools that help us maintain an association between data files and metadata descriptions of those files. The CME system maintains, and provides access to, a collection of valuable geophysical data sets. The current CME Digital Library holdings include a collection of 60 ground motion simulation results calculated by a SCEC/PEER working group and a collection of Greens Functions calculated for 33 TriNet broadband receiver sites in the Los Angeles area.

  11. MSE measurements for sawtooth and non-inductive current drive studies in KSTAR

    Science.gov (United States)

    Ko, J.; Park, H.; Bea, Y. S.; Chung, J.; Jeon, Y. M.

    2016-10-01

    Two major topics where the measurement of the magnetic-field-line rotational transform profiles in toroidal plasma systems include the long-standing issue of complete versus incomplete reconnection model of the sawtooth instability and the issue with future reactor-relevant tokamak devices in which non-inductive steady state current sustainment is essential. The motional Stark effect (MSE) diagnostic based on the photoelastic-modulator (PEM) approach is one of the most reliable means to measure the internal magnetic pitch, and thus the rotational transform, or its reciprocal (q), profiles. The MSE system has been commissioned for the Korea Superconducting Tokamak Advanced Research (KSTAR) along with the development of various techniques to minimize systematic offset errors such as Faraday rotation and mis-alignment of the bandpass filters. The diagnostic has revealed the central q is well correlated with the sawtooth oscillation, maintaining its value above unity during the MHD quiescent period and that the response of the q profile to external current drive such as electron cyclotron wave injection not only involves the local change of the pitch angle gradient but also a significant shift of the magnetic topology due to the wave energy transport. Work supported by the Ministry of Science, ICT and Future Planning, Korea.

  12. Integrated Plasma Simulation of Lower Hybrid Current Drive Modification of Sawtooth in Alcator C-Mod

    Science.gov (United States)

    Bonoli, P. T.; Hubbard, A. E.; Schmidt, A. E.; Wright, J. C.; Kessel, C. E.; Batchelor, D. B.; Berry, L. A.; Harvey, R. W.

    2010-11-01

    Experiments were performed in Alcator C-Mod, where the onset time for sawteeth was delayed significantly (up to 0.5 s) relative to ohmically heated plasmas, through injection of off-axis LH current drive power [1]. In this poster we discuss simulations of these experiments using the Integrated Plasma Simulator (IPS) [2], through which driven current density profiles and hard x-ray spectra are computed using a ray tracing code (GENRAY) and Fokker Planck code (CQL3D) [3], that are executed repeatedly in time. The background plasma is evolved in these simulations using the TSC transport code with the Porcelli sawtooth model [4]. [4pt] [1] C. E. Kessel et al, Bull. of the Am. Phys. Soc. 53, Poster PP6.00074 (2008). [0pt] [2] D. Batchelor et al, Journal of Physics: Conf. Series 125, 012039 (2008). [0pt] [3] R. W. Harvey and M. G. McCoy, Proc. of the IAEA Tech. Comm. Mtg. on Sim. and Mod. of Therm. Plasmas, Montreal, Canada (1992). [0pt] [4] S. C. Jardin et al, Journal Comp. Phys. 66, 481 (1986).

  13. Component development for the ITER Ion Cyclotron Heating and Current Drive Transmission Line and Matching System

    Science.gov (United States)

    Goulding, R. H.; McCarthy, M. P.; Rasmussen, D. A.; Swain, D. W.; Barber, G. C.; Barbier, C. N.; Cambell, I. H.; Gray, S. L.; Moon, R. L.; Pesavento, P. V.; Sanabria, R. M.; Fredd, E.; Greenough, N.

    2013-10-01

    The transmission line and matching network for the ITER Ion Cyclotron Heating and Current Drive System feeds two equatorial launchers, each with 24 phased current straps combined into groups of three, and each designed to couple up to 20 MW into ELMy H-mode plasmas in the frequency range 40-55 MHz, for pulse lengths up to 3600 s. The network includes > 1 km of 50 Ohm 300 mm diameter transmission line carrying up to 6 MW net power per line at VSWR = 1.5. In addition, there are 8 power splitters, 32 hybrid phase shifters incorporating 64 tuning stubs, 32 additional tuning stubs, and 36 vacuum capacitors, which are configured to provide pre-matching in the port cell region adjacent to the antenna, final matching, decoupling of mutual inductances between antenna elements, and passive ELM resilience. The development and design of the various system components will be discussed. High power tests of components have begun, and the latest results will be presented. This manuscript has been authored by UT-Battelle, LLC, under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy.

  14. Transmission line component testing for the ITER Ion Cyclotron Heating and Current Drive System

    Science.gov (United States)

    Goulding, Richard; Bell, G. L.; Deibele, C. E.; McCarthy, M. P.; Rasmussen, D. A.; Swain, D. W.; Barber, G. C.; Barbier, C. N.; Cambell, I. H.; Moon, R. L.; Pesavento, P. V.; Fredd, E.; Greenough, N.; Kung, C.

    2014-10-01

    High power RF testing is underway to evaluate transmission line components for the ITER Ion Cyclotron Heating and Current Drive System. The transmission line has a characteristic impedance Z0 = 50 Ω and a nominal outer diameter of 305 mm. It is specified to carry up to 6 MW at VSWR = 1.5 for 3600 s pulses, with transient voltages up to 40 kV. The transmission line is actively cooled, with turbulent gas flow (N2) used to transfer heat from the inner to outer conductor, which is water cooled. High voltage and high current testing of components has been performed using resonant lines generating steady state voltages of 35 kV and transient voltages up to 60 kV. A resonant ring, which has operated with circulating power of 6 MW for 1 hr pulses, is being used to test high power, low VSWR operation. Components tested to date include gas barriers, straight sections of various lengths, and 90 degree elbows. Designs tested include gas barriers fabricated from quartz and aluminum nitride, and transmission lines with quartz and alumina inner conductor supports. The latest results will be presented. This manuscript has been authored by UT-Battelle, LLC, under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy.

  15. Melt textured YBaCuO transport current capability. Application to current limitation; Capacite de transport et de limitation du courant des materiaux YBaCuO textures

    Energy Technology Data Exchange (ETDEWEB)

    Porcar, L.; Belmont, O.; Noudem, J.G.; Barbut, J.M.; Barrault, M. [Schneider Electric S.A., Grenoble (France); Bourgault, D.; Chaud, X.; Tournier, R. [CNRS-EPM/Matformag, Grenoble (France); Tixador, P. [CNRS-CRTBT/LEG, Grenoble (France)

    1998-01-01

    Pulsed and permanent sinusoidal transport current have been applied to melt textured Y{sub 1}Ba{sub 2}Cu{sub 3}O{sub 7-{delta}} in order to estimate its current limitation capability. High pulsed transport currents reaching 9000A (23000 A/cm{sup 2}) crossed a 4 cm long sample. In permanent sinusoidal current, 3000 A (7800 A/cm{sup 2}) crossed the sample without showing any resistive losses. Above the critical current, the transition from the superconducting to the normal state is strongly abrupt. (orig.). 8 refs.

  16. Correlational and Differential Influence of Historical Cost and Current Cost Profits on the Operating Capabilities of the Firm

    OpenAIRE

    S. A. Effiong; J. O. Udoayang; A. I. Asuquo

    2011-01-01

    The study investigated the correlation and differential influence of historical cost and current cost profits on the operating capabilities of the firm. The financial statements of thirty-one Nigerian Companies were surveyed and adjusted for effects of price changes using the Consumers¡¯ Price Index (CPI). Correlation influence between the historical cost profits on the operating ability of the firm was measured and established on one hand and that of current cost profit on the other hand. Di...

  17. NTM stabilization by alternating O-point EC current drive using a high-power diplexer

    Science.gov (United States)

    Kasparek, W.; Doelman, N.; Stober, J.; Maraschek, M.; Zohm, H.; Monaco, F.; Eixenberger, H.; Klop, W.; Wagner, D.; Schubert, M.; Schütz, H.; Grünwald, G.; Plaum, B.; Munk, R.; Schlüter, K. H.; ASDEX Upgrade Team

    2016-12-01

    At the tokamak ASDEX Upgrade, experiments to stabilize neoclassical tearing modes (NTMs) by electron cyclotron (EC) heating and current drive in the O-points of the magnetic islands were performed. For the first time, injection into the O-points of the revolving islands was performed via a fast directional switch, which toggled the EC power between two launchers synchronously to the island rotation. The switching was performed by a resonant diplexer employing a sharp resonance in the transfer function, and a small frequency modulation of the feeding gyrotron around the slope of the resonance. Thus, toggling of the power between the two outputs of the diplexer connected to two articulating launchers was possible. Phasing and control of the modulation were performed via a set of Mirnov coils and appropriate signal processing. In the paper, technological issues, the design of the diplexer, the tracking of the diplexer resonance to the gyrotron frequency, the generation and processing of control signals for the gyrotron, and the typical performance concerning switching contrast and efficiency are discussed. The plasma scenario is described, and plasma experiments are presented, where the launchers scanned the region of the resonant surface continuously and also where the launchers were at a fixed position near to the q  =  1.5-surface. In the second case, complete stabilization of a 3/2 NTM could be reached. These experiments are also seen as a technical demonstration for the applicability of diplexers in large-scale ECRH systems.

  18. Proposed high voltage power supply for the ITER relevant lower hybrid current drive system

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, P.K., E-mail: pramod@ipr.res.in [Institute for Plasma Research, Bhat, Gandhinagar, Gujarat (India); Kazarian, F.; Garibaldi, P.; Gassman, T. [ITER Organization, CS 90 046, 13067 Saint-Paul-Les-Durance (France); Artaud, J.F. [CEA, IRFM, F-13108 Saint-Paul-lez-Durance (France); Bae, Y.S. [National Fusion Research Institute, Daejeon (Korea, Republic of); Belo, J. [Associacao Euratom-IST, Centro de Fusao Nuclear, Lisboa (Portugal); Berger-By, G.; Bernard, J.M.; Cara, Ph. [CEA, IRFM, F-13108 Saint-Paul-lez-Durance (France); Cardinali, A.; Castaldo, C.; Ceccuzzi, S.; Cesario, R. [Associazione Euratom-ENEA sulla Fusione, CR Frascati, Rome (Italy); Decker, J.; Delpech, L.; Ekedahl, A.; Garcia, J.; Goniche, M.; Guilhem, D. [CEA, IRFM, F-13108 Saint-Paul-lez-Durance (France)

    2011-10-15

    In the framework of the EFDA task HCD-08-03-01, the ITER lower hybrid current drive (LHCD) system design has been reviewed. The system aims to generate 24 MW of RF power at 5 GHz, of which 20 MW would be coupled to the plasmas. The present state of the art does not allow envisaging a unitary output of the klystrons exceeding 500 kW, so the project is based on 48 klystron units, leaving some margin when the transmission lines losses are taken into account. A high voltage power supply (HVPS), required to operate the klystrons, is proposed. A single HVPS would be used to feed and operate four klystrons in parallel configuration. Based on the above considerations, it is proposed to design and develop twelve HVPS, based on pulse step modulator (PSM) technology, each rated for 90 kV/90 A. This paper describes in details, the typical electrical requirements and the conceptual design of the proposed HVPS for the ITER LHCD system.

  19. Extended magnetohydrodynamic simulations of field reversed configuration formation and sustainment with rotating magnetic field current drive

    Science.gov (United States)

    Milroy, R. D.; Kim, C. C.; Sovinec, C. R.

    2010-06-01

    Three-dimensional simulations of field reversed configuration (FRC) formation and sustainment with rotating magnetic field (RMF) current drive have been performed with the NIMROD code [C. R. Sovinec et al., J. Comput. Phys. 195, 355 (2004)]. The Hall term is a zeroth order effect with strong coupling between Fourier components, and recent enhancements to the NIMROD preconditioner allow much larger time steps than was previously possible. Boundary conditions to capture the effects of a finite length RMF antenna have been added, and simulations of FRC formation from a uniform background plasma have been performed with parameters relevant to the translation, confinement, and sustainment-upgrade experiment at the University of Washington [H. Y. Guo, A. L. Hoffman, and R. D. Milroy, Phys. Plasmas 14, 112502 (2007)]. The effects of both even-parity and odd-parity antennas have been investigated, and there is no evidence of a disruptive instability for either antenna type. It has been found that RMF effects extend considerably beyond the ends of the antenna, and that a large n =0 Bθ can develop in the open-field line region, producing a back torque opposing the RMF.

  20. High Power Antenna Design for Lower Hybrid Current Drive in MST

    Science.gov (United States)

    Thomas, M. A.; Goetz, J. A.; Kaufman, M. C.; Oliva, S. P.; Caughman, J. B. O.; Ryan, P. M.

    2003-10-01

    RF current drive has been proposed as a method for reducing the tearing fluctuations that are responsible for anomalous energy transport in the RFP. A system for launching lower hybrid slow waves at 800 MHz and n_||= 7.5 is now in operation at up to 50 kW on MST. The antenna is an enclosed interdigital line using λ/4 resonators with an opening in the cavity through which the wave is coupled to the plasma. It has an untuned VSWR of ˜2, and is instrumented on 5 of its 23 elements to allow measurement of damping length. The antenna design is being optimized for higher power handling. Improvements include larger vacuum feedthroughs, better impedance matching, and RF instrumentation on all resonators. The new antenna will be modeled in Microwave Studio^TM. The goal is a design which can handle ˜250 kW and presents a VSWR of 1.4 or better without external tuning. Full instrumentation will allow more detailed power deposition measurements.

  1. A camera for imaging hard x-rays from suprathermal electrons during lower hybrid current drive on PBX-M

    Energy Technology Data Exchange (ETDEWEB)

    von Goeler, S.; Kaita, R.; Bernabei, S.; Davis, W.; Fishman, H.; Gettelfinger, G.; Ignat, D.; Roney, P.; Stevens, J.; Stodiek, W. (Princeton Univ., NJ (United States). Plasma Physics Lab.); Jones, S.; Paoletti, F. (Massachusetts Inst. of Tech., Cambridge, MA (United States). Plasma Fusion Center); Petravich, G. (Hungarian Academy of Sciences, Budapest (Hungary). Central Research Inst. for Physics); Rimini,

    1993-05-01

    During lower hybrid current drive (LHCD), suprathermal electrons are generated that emit hard X-ray bremsstrahlung. A pinhole camera has been installed on the PBX-M tokamak that records 128 [times] 128 pixel images of the bremsstrahlung with a 3 ms time resolution. This camera has identified hollow radiation profiles on PBX-M, indicating off-axis current drive. The detector is a 9in. dia. intensifier. A detailed account of the construction of the Hard X-ray Camera, its operation, and its performance is given.

  2. Will Robots Ever Replace Attendants? Exploring the Current Capabilities and Future Potential of Robots in Education and Rehabilitation.

    Science.gov (United States)

    Lees, David; LePage, Pamela

    1994-01-01

    This article describes the current capabilities and future potential of robots designed as supplements or replacements for human assistants or as tools for education and rehabilitation of people with disabilities. Review of robots providing educational, vocational, or independent living assistance concludes that eventually effective, reliable…

  3. Improving Aerosol and Visibility Forecasting Capabilities Using Current and Future Generations of Satellite Observations

    Science.gov (United States)

    2015-08-27

    indicate that the assimilation of satellite observations significantly improves NAAPS aerosol forecasting capability and reliability. To fully utilize...method derives a semi-quantitative indicator of nighttime x using artificial light sources. Nighttime x retrievals from the newly-developed method are...Kemper, T. Craig, I. Ginis , Evaluation of Maine aerosol production simulated using the WaveWatchlll prognostic Wave Model coupled to the Community

  4. Quasi-linear modeling of lower hybrid current drive in ITER and DEMO

    Energy Technology Data Exchange (ETDEWEB)

    Cardinali, A., E-mail: alessandro.cardinali@enea.it; Cesario, R.; Panaccione, L.; Santini, F.; Amicucci, L.; Castaldo, C.; Ceccuzzi, S.; Mirizzi, F.; Tuccillo, A. A. [ENEA, Unità Tecnica Fusione, Via E Fermi 45 Rome (Italy)

    2015-12-10

    First pass absorption of the Lower Hybrid waves in thermonuclear devices like ITER and DEMO is modeled by coupling the ray tracing equations with the quasi-linear evolution of the electron distribution function in 2D velocity space. As usually assumed, the Lower Hybrid Current Drive is not effective in a plasma of a tokamak fusion reactor, owing to the accessibility condition which, depending on the density, restricts the parallel wavenumber to values greater than n{sub ∥crit} and, at the same time, to the high electron temperature that would enhance the wave absorption and then restricts the RF power deposition to the very periphery of the plasma column (near the separatrix). In this work, by extensively using the “ray{sup star}” code, a parametric study of the propagation and absorption of the LH wave as function of the coupled wave spectrum (as its width, and peak value), has been performed very accurately. Such a careful investigation aims at controlling the power deposition layer possibly in the external half radius of the plasma, thus providing a valuable aid to the solution of how to control the plasma current profile in a toroidal magnetic configuration, and how to help the suppression of MHD mode that can develop in the outer part of the plasma. This analysis is useful not only for exploring the possibility of profile control of a pulsed operation reactor as well as the tearing mode stabilization, but also in order to reconsider the feasibility of steady state regime for DEMO.

  5. Current practices of driving restriction implementation for patients with brain tumors.

    Science.gov (United States)

    Thomas, Sayana; Mehta, Minesh P; Kuo, John S; Ian Robins, H; Khuntia, Deepak

    2011-07-01

    Brain tumors may impair functioning in several neuro-cognitive domains and interfere with sophisticated tasks, such as driving motor vehicles. No formalized national guidelines or recommendations for driving restrictions in patients with brain tumors exist in the US. We created and administered a 24 question survey to 1,157 US medical practitioners, mostly neurosurgeons, radiation oncologists, and medical oncologists, to identify their knowledge of local driving restriction laws and their practice patterns regarding driving restriction instructions to brain tumor patients. Response were collected from 251 (21.7%) and analyzed from 221 (19%) recipients. Seventy-one percent of the respondents indicated they discuss driving recommendations/restrictions with brain tumor patients, with 82% primarily basing this on seizure activity. Approximately 28% of respondents were unsure if they are required by their State's motor vehicle licensing authority to report medically impaired drivers. Respondents felt that longer periods of restriction prior to re-evaluation are warranted in patients with malignant versus benign brain tumors and high versus low grade gliomas. Only 25% of respondents use formal, standardized testing to determine driving eligibility and approximately 31% address driving restrictions in every patient with a brain tumor. This survey highlights the lack of consensus regarding the responsibilities of physicians treating brain tumor patients in designing and enforcing driving restrictions. We propose that a panel of experts generate driving restriction guidelines to be used in conjunction with objective testing of motor and sensory impairment. These would aid practitioners in developing individualized driving restrictions for every brain tumor patient.

  6. Enhanced Phase-Shifted Current Control for Harmonic Cancellation in Three-Phase Multiple Adjustable Speed Drive Systems

    DEFF Research Database (Denmark)

    Yang, Yongheng; Davari, Pooya; Zare, Firuz

    2017-01-01

    A phase-shifted current control can be employed to mitigate certain harmonics induced by the Diode Rectifiers (DR) and Silicon-Controlled Rectifiers (SCR) as the front-ends of multiple parallel Adjustable Speed Drive (ASD) systems. However, the effectiveness of the phase-shifted control relies on......-shifted current control is a cost-effective solution to multiple ASD systems in terms of harmonic cancellation.......A phase-shifted current control can be employed to mitigate certain harmonics induced by the Diode Rectifiers (DR) and Silicon-Controlled Rectifiers (SCR) as the front-ends of multiple parallel Adjustable Speed Drive (ASD) systems. However, the effectiveness of the phase-shifted control relies...... on the loading condition of each drive unit as well as the number of drives in parallel. In order to enhance the harmonic cancellation by means of the phase-shifted current control, the currents drawn by the rectifiers should be maintained almost at the same level. Thus, this paper firstly analyzes the impact...

  7. A compact 45 kV curve tracer with picoampere current measurement capability

    Science.gov (United States)

    Sullivan, W. W.; Mauch, D.; Bullick, A.; Hettler, C.; Neuber, A.; Dickens, J.

    2013-03-01

    This paper discusses a compact high voltage curve tracer for high voltage semiconductor device characterization. The system sources up to 3 mA at up to 45 kV in dc conditions. It measures from 328 V to 60 kV with 15 V resolution and from 9.4 pA to 4 mA with 100 fA minimum resolution. Control software for the system is written in Microsoft Visual C# and features real-time measurement control and IV plotting, arc-protection and detection, an electrically isolated universal serial bus interface, and easy data exporting capabilities. The system has survived numerous catastrophic high voltage device-under-test arcing failures with no loss of measurement capability or system damage. Overall sweep times are typically under 2 min, and the curve tracer system was used to characterize the blocking performance of high voltage ceramic capacitors, high voltage silicon carbide photoconductive semiconductor switches, and high voltage coaxial cable.

  8. Operating capability as a PQ/PV node of a direct-drive wind turbine based on a permanent magnet synchronous generator

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez, L.M.; Garcia, C.A. [Department of Electrical Engineering, University of Cadiz, EPS Algeciras, Avda. Ramon Puyol s/n,11202 Algeciras (Cadiz) (Spain); Jurado, F. [Department of Electrical Engineering, University of Jaen, EPS Linares, C/ Alfonso X n . 28, 23700 Linares (Jaen) (Spain)

    2010-06-15

    This paper describes the modelling and control system of a direct-drive PMSG wind turbine for effective active and reactive power generation control and voltage control at the grid connection point. This study focuses on the maximum power capability of the wind turbine, which is limited by its generator and power converter. The ability of this model and control strategy are assessed by means of simulations and discussed at length. The results of our study show that a PMSG wind turbine is able to actively participate in grid operation because it can independently control active and reactive power production (operating as a PQ node) or the active power and voltage at the connection node (operating as a PV node). (author)

  9. The Influence of Neutral Beam Injection on the Heating and Current Drive with Electron Cyclotron Wave on EAST

    Science.gov (United States)

    Chang, Pengxiang; Wu, Bin; Wang, Jinfang; Li, Yingying; Wang, Xiaoguang; Xu, Handong; Wang, Xiaojie; Liu, Yong; Zhao, Hailin; Hao, Baolong; Yang, Zhen; Zheng, Ting; Hu, Chundong

    2016-11-01

    Both neutral beam injection (NBI) and electron cyclotron resonance heating (ECRH) have been applied on the Experimental Advanced Superconducting Tokamak (EAST) in the 2015 campaign. In order to achieve more effective heating and current drive, the effects of NBI on the heating and current drive with electron cyclotron wave (ECW) are analyzed utilizing the code TORAY and experimental data in the shot #54411 and #54417. According to the experimental and simulated results, for the heating with ECW, NBI can improve the heating efficiency and move the power deposition place towards the inside of the plasma. On the other hand, for the electron cyclotron current drive (ECCD), NBI can also improve the efficiency of ECCD and move the place of ECCD inward. These results will be valuable for the center heating, the achievement of fully non-inductive current drive operation and the suppression of magnetohydrodynamic (MHD) instabilities with ECW on EAST or ITER with many auxiliary heating methods. supported by the National Magnetic Confinement Fusion Science Program of China (Nos. 2013GB101001 and 2014DFG61950) and National Natural Science Foundation of China (Nos. 11405212 and 11175211)

  10. High RF power test of a CFC antenna module for lower hybrid current drive

    Energy Technology Data Exchange (ETDEWEB)

    Maebara, S.; Seki, M.; Ikeda, Y.; Kiyono, K.; Suganuma, K.; Imai, T. [Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan). Naka Fusion Research Establishment; Goniche, M.; Bibet, Ph.; Brossaud, J.; Cano, V.; Kazarian-Vibert, F.; Froissard, P.; Rey, G. [Association Euratom-CEA Cadarache, 13 - Saint-Paul-lez-Durance (France). Dept. de Recherches sur la Fusion Controlee

    1998-07-01

    A mock-up of a 3.7 GHz Lower Hybrid Current Drive (LHCD) antenna module was fabricated from Carbon Fibre Composite (CFC) for the development of heat resistive low Z front facing the plasma. This 2 divided waveguide module is made from CFC plates and rods which are Cu-plated to reduce the RF losses. The withstand-voltage, the RF properties and the outgassing rates for long pulses and high RF power were tested at the Lower Hybrid test bed facility of Cadarache. A reference module made from Dispersion Strengthened Copper (DSC) was also fabricated. After the short pulse conditioning, long pulses with a power density ranging between 50 and 150 MW/m{sup 2} were performed with no breakdowns on the CFC module. It was also checked that the highest power density, up to 150 MW/m{sup 2}, could be transmitted when the waveguides are filled with H2 at a pressure of 5 x 10{sup -2} Pa. During a long pulse, the power reflection coefficient remains low in the 0.8-1.3 % range and no significant change in the reflection coefficient is measured after the thermal cycling provided by the long pulse operation. From thermocouple measurements, RF losses of the copper coated CFC and the DSC modules were compared. No significant differences were measured. From pressure measurements, it was found that the outgassing rate of Cu-plated CFC is about 6-7 times larger than of DSC at 300 deg.C. It is concluded that a CFC module is an attractive candidate for the hardening of the tip of the LHCD antenna. (author)

  11. Predictions for the drive capabilities of the RancheroS Flux Compression Generator into various load inductances using the Eulerian AMR Code Roxane

    Energy Technology Data Exchange (ETDEWEB)

    Watt, Robert Gregory [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-06-06

    The Ranchero Magnetic Flux Compression Generator (FCG) has been used to create current pulses in the 10-­100 MA range for driving both “static” low inductance (0.5 nH) loads1 for generator demonstration purposes and high inductance (10-­20 nH) imploding liner loads2 for ultimate use in physics experiments at very high energy density. Simulations of the standard Ranchero generator have recently shown that it had a design issue that could lead to flux trapping in the generator, and a non-­ robust predictability in its use in high energy density experiments. A re-­examination of the design concept for the standard Ranchero generator, prompted by the possible appearance of an aneurism at the output glide plane, has led to a new generation of Ranchero generators designated the RancheroS (for swooped). This generator has removed the problematic output glide plane and replaced it with a region of constantly increasing diameter in the output end of the FCG cavity in which the armature is driven outward under the influence of an additional HE load not present in the original Ranchero. The resultant RancheroS generator, to be tested in LA43S-­L13, probably in early FY17, has a significantly increased initial inductance and may be able to drive a somewhat higher load inductance than the standard Ranchero. This report will use the Eulerian AMR code Roxane to study the ability of the new design to drive static loads, with a goal of providing a database corresponding to the load inductances for which the generator might be used and the anticipated peak currents such loads might produce in physics experiments. Such a database, combined with a simple analytic model of an ideal generator, where d(LI)/dt = 0, and supplemented by earlier estimates of losses in actual use of the standard Ranchero, scaled to estimate the increase in losses due to the longer current carrying perimeter in the RancheroS, can then be used to bound the expectations for the current drive one may

  12. Optimization of RF power absorption by optimization techniques using the lower hybrid current drive of FTU

    Energy Technology Data Exchange (ETDEWEB)

    Centioli, C. [Associazione Euratom/ENEA Sulla Fusione, Centro Ricerche Frascati, Via E. Fermi 45, CP 65, 00044 Frascati, Rome (Italy); Iannone, F. [Associazione Euratom/ENEA Sulla Fusione, Centro Ricerche Frascati, Via E. Fermi 45, CP 65, 00044 Frascati, Rome (Italy); Mazza, G. [Associazione Euratom/ENEA Sulla Fusione, Centro Ricerche Frascati, Via E. Fermi 45, CP 65, 00044 Frascati, Rome (Italy); Panella, M. [Associazione Euratom/ENEA Sulla Fusione, Centro Ricerche Frascati, Via E. Fermi 45, CP 65, 00044 Frascati, Rome (Italy); Pangione, L. [Dipartimento di Informatica, Sistemi e Produzione, Universita di Roma, Tor Vergata, Via del Politecnico 1, 00133 Rome (Italy)]. E-mail: pangione@frascati.enea.it; Podda, S. [Associazione Euratom/ENEA Sulla Fusione, Centro Ricerche Frascati, Via E. Fermi 45, CP 65, 00044 Frascati, Rome (Italy); Tuccillo, A. [Associazione Euratom/ENEA Sulla Fusione, Centro Ricerche Frascati, Via E. Fermi 45, CP 65, 00044 Frascati, Rome (Italy); Vitale, V. [Associazione Euratom/ENEA Sulla Fusione, Centro Ricerche Frascati, Via E. Fermi 45, CP 65, 00044 Frascati, Rome (Italy); Zaccarian, L. [Dipartimento di Informatica, Sistemi e Produzione, Universita di Roma, Tor Vergata, Via del Politecnico 1, 00133 Rome (Italy)

    2005-11-15

    In this paper, we will report on the experimental results arising from the implementation of optimization techniques to maximize the RF power coupling versus the plasma conditions in the FTU experimental facility. These experiments are carried out by employing the open-source Linux-RTAI control system currently running on the FTU digital feedback loop. The RF power source under consideration is a lower hybrid system (LH) based on six gyrotrons with a nominal power output capability of 1.1 MW each. The optimization of the coupling level between the plasma and the emitting antenna reduces the reflected power, thus maximizing the heating effects in addition to avoiding danger to the emitter (equivalently, annoying safety shutdowns of the system). To this aim, the plasma displacement is modified by suitably adjusting the reference input to the stabilizing feedback, according to a steepest descent algorithm. It will be shown in the paper how this algorithm achieves a satisfactory level of robustness with respect to measurement errors and well performs both in simulation and in experimental tests, thus leading to an improved effectiveness of the RF heating system.

  13. Study of lower hybrid current drive efficiency and its correlation with photon temperatures in the HT-7 tokamak

    Science.gov (United States)

    Younis, J.; Wan, B. N.; Lin, S. Y.; Shi, Y. J.; Ding, B. J.; Gong, X.; HT-7 Team

    2009-07-01

    Lower hybrid current drive (LHCD) efficiency is a very important parameter. The experimental current drive efficiency is defined as η = IrfneR/PLH, where Irf is the current driven by the lower hybrid waves (LHWs), ne is the central line-average density, R is the major radius of the plasma and PLH is the injected LH wave power absorbed by the plasma through Landau damping. A study of current drive efficiency of LHWs in the HT-7 tokamak has been carried out in the parameter ranges: ne = (1.2-2.5) × 1019 m-3, Ip = (80-200) kA, Bt = 1.8 T, PLH = (188-532) kW in the limiter configuration. Current drive efficiency is investigated through a simple correlation with photon temperature and normalized intensity of fast electron bremstrahlung emission, which is, in the first approximation, proportional to the averaged velocity and population of the fast electrons. The plasma current scanning experiment shows that CD efficiency increase is due to the increase in both the photon temperature and the population of the fast electrons generated by LHWs. The density scanning experiment shows that as the plasma density is increased, an increment in CD efficiency along with the increase in the population of fast electrons is observed. The slowing down through the collisions with bulk electrons is mainly responsible for the decreased photon temperature during the plasma density scan. These experiments strongly suggest the dominant role of the population of fast electrons generated by LHCD and the generation of the current carried by fast electrons.

  14. Drift chamber electronics with multi-hit capability for time and current division measurements

    Energy Technology Data Exchange (ETDEWEB)

    Manarin, A.; Pregernig, L.; Rabany, M.; Saban, R.; Vismara, G.

    1983-11-15

    Drift chambers have been installed for luminosity measurements in intersection 5 of the SPS accelerator working in panti p colliding mode. The required electronics is described. The system is able to process up to 16 hits per wire with a double pulse resolution of 40 ns; drift time and current division, with 1.25 ns and 1.6% resolution respectively, are recorded. Transconductance preamplifiers and discriminators are directly mounted on the chamber; 160 m of twisted-apir cable bring the signals to the digitizer unit. Coarse time is measured using RAM techniques, while fine time is obtained by means of a microstrip delay associated with a 100 K ECL priority encoder. Current division used a single 50 MHz Flash ADC which alows 26 dB dynamic range with 6 bit resolution. First operational results are reported.

  15. Characterisation of the incident beam and current diffraction capabilities on the VESUVIO spectrometer

    Science.gov (United States)

    Romanelli, G.; Krzystyniak, M.; Senesi, R.; Raspino, D.; Boxall, J.; Pooley, D.; Moorby, S.; Schooneveld, E.; Rhodes, N. J.; Andreani, C.; Fernandez-Alonso, F.

    2017-09-01

    The VESUVIO spectrometer at the ISIS pulsed neutron and muon source is a unique instrument amongst those available at neutron facilities. This is the only inverted-geometry neutron spectrometer accessing values of energy and wavevector transfer above tens of eV and {\\mathringA}-1 , respectively, and where deep inelastic neutron scattering experiments are routinely performed. As such, the procedure at the base of the technique has been previously described in an article published by this journal (Mayers and Reiter 2012 Meas. Sci. Technol. 23 045902). The instrument has recently witnessed an upsurge of interest due to a new trend to accommodate, within a single experiment, neutron diffraction and transmission measurements in addition to deep inelastic neutron scattering. This work presents a broader description of the instrument following these recent developments. In particular, we assess the absolute intensity and two-dimensional profile of the incident neutron beam and the capabilities of the backscattering diffraction banks. All results are discussed in the light of recent changes to the moderator viewed by the instrument. We find that VESUVIO has to be considered a high-resolution diffractometer as much as other diffractometers at ISIS, with a resolution as high as 2× 10-3 in backscattering. Also, we describe the extension of the wavelength range of the instrument to include lower neutron energies for diffraction measurements, an upgrade that could be readily applied to other neutron instruments as well.

  16. Integrated Computational Materials Engineering of Titanium: Current Capabilities Being Developed Under the Metals Affordability Initiative

    Science.gov (United States)

    Glavicic, M. G.; Venkatesh, V.

    2014-07-01

    A technical review of the titanium model development programs currently funded under the Metals Affordability Initiative is presented. Progress of the "Advanced Titanium Alloy Microstructure and Mechanical Property Modeling" and "ICME of Microtexture Evolution and its Effect on Cold Dwell/High/Low Cycle Fatigue Behavior of Dual Phase Titanium Alloys" will be reviewed followed by a discussion of the future modeling needs of the aerospace industry.

  17. When do we think it is Safe to Drive after Hand Surgery? – Current Practice and Legal Perspective

    LENUS (Irish Health Repository)

    Murphy, SF

    2016-11-01

    Patients recovering from hand surgery frequently ask when it is safe to drive and it is unclear where the responsibility lies; the surgeon, the patient or the insurance company. An eight-question survey looking at various aspects of clinical practice was circulated to consultant and trainee plastic and orthopaedic surgeons in Ireland and the UK. Of the 89 surgeons who replied, (53%) felt the decision when to drive was the patient’s compared with the insurance company (40%) and the surgeon (7%). 80% advised patients to contact their insurance company. 87% were unaware of current regulations or guidelines. National guidelines were vague and left the decision with the treating doctor. Similarly, major insurers advise patients to contact their doctor for advice. From a legal standpoint, the patient has a duty of care to other road users to be in full control of his vehicle prior to driving, regardless of any advice received.

  18. Ultra-fast dynamic imaging: an overview of current techniques, their capabilities and future prospects

    Science.gov (United States)

    Altucci, C.; Velotta, R.; Marangos, J. P.

    2010-06-01

    In this review we attempt to sketch an overview of the various methods currently being used or under development to enable ultra-fast dynamic imaging of matter. We concentrate on those techniques which combine atomic scale spatial resolution and femtosecond or even sub-femtosecond temporal resolution. In part this review was inspired and informed by the material presented at the 'Ultrafast Dynamic Imaging II' workshop held in Ischia, Italy in April 2009, but we also have drawn on a wider background of material especially when discussing the emerging laser-based methods.

  19. Current Sounding Capability From Satellite Meteorological Observation With Ultraspectral Infrared Instruments

    Science.gov (United States)

    Zhou, Daniel K.; Liu, Xu; Larar, Allen M.

    2008-01-01

    cloud top level are obtained. For both optically thin and thick cloud situations, the cloud top height can be retrieved with relatively high accuracy (i.e., error less than 1 km). Retrievals of atmospheric soundings, surface properties, and cloud microphysical properties with the AIRS and IASI observations are obtained and presented. These retrievals are further inter-compared with those obtained from airborne FTS system, such as the NPOESS Airborne Sounder Testbed? Interferometer (NAST I), dedicated dropsondes, radiosondes, and ground based Raman Lidar. The capabilities of satellite ultra-spectral sounder such as the AIRS and IASI are investigated. These advanced satellite ultraspectral infrared instruments are now playing an important role in satellite meteorological observation for numerical weather prediction.

  20. Performance Evaluation of Electronic Inductor-Based Adjustable Speed Drives with Respect to Line Current Interharmonics

    DEFF Research Database (Denmark)

    Soltani, Hamid; Davari, Pooya; Zare, Firuz;

    2017-01-01

    Electronic Inductor (EI)-based front-end rectifiers have a large potential to become the prominent next generation of Active Front End (AFE) topology used in many applications including Adjustable Speed Drives (ASDs) for systems having unidirectional power flow. The EI-based ASD is mostly attract...

  1. Thorium-230 dating of carbonates: current technical capabilities and major applications

    Science.gov (United States)

    Edwards, R. L.; Cheng, H.; Pythoud, M.; Lu, Y.; Zhang, P.; Nissen, J.; Berry, A.; Cross, M.

    2015-12-01

    Uranium-thorium or Th-230 dating has proven to be an important tool in determining the timing of events in the late Quaternary. Among the major applications are: the timing of sea level change, the timing of continental climate change as preserved in cave archives, the timing of climate change in marine and ice core archives through correlation to Th-230 - dated cave records, and calibration of the radiocarbon timescale. The success of these applications has been driven by continuing technical advances in the measurement of the rare actinide isotopes, U-234 and Th-230. The advances have improved the precision, sensitivity, and accuracy of the measurements. The main factor in measurement improvement has been an increase of about 5 orders of magnitude (over the past 30 years) in the fraction of the sample that can be detected, dramatically improving counting statistics, as well as measurement sensitivity. The 5-order of magnitude improvement, comes largely from the shift to mass spectrometric measurement techniques, but also has resulted from subsequent improvement in ionization plus transmission efficiency. While additional improvement above the 5-order of magnitude figure may be possible, current efforts are focused on improving the accuracy of the measurements, standardizing gravimetric standards among laboratories, and shortening measurement times. These efforts will be discussed along with summary results of some of the major applications.

  2. Design and Preparation of RF System for the Lower Hybrid Fast Wave Heating and Current Drive Research on VEST

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sun Ho; Jeong, Seung Ho [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Lee, Hyun Woo; Lee, Byung Je [Kwang Woon University, Chuncheon (Korea, Republic of); Jo, Jong Gab; Lee, Hyun Young; Hwang, Yong Seok [Seoul National University, Seoul (Korea, Republic of)

    2015-10-15

    Continuous current drive is one of the key issues for tokamak to be a commercial fusion reactor. As a part of new and efficient current drive concept research by using a Lower Hybrid Fast Wave (LHFW), the experimental study is planned on Versatile Experiment Spherical Torus (VEST) and a RF system is being developed in collaboration with Kwang Woon University (KWU), Korea Accelerator Plasma Research Association (KAPRA) and Seoul National University (SNU). The LHFW RF system includes UHF band klystron, inter-digital antenna, RF diagnostics and power transmission sub components such as circulator, DC breaker, vacuum feed-thru. The design and preparation status of the RF system will be presented in the meeting in detail. A RF system has been designed and prepared for the experimental study of efficient current drive by using Lower Hybrid Fast Wave. Overall LHFW RF system including diagnostics is designed to deliver about 10 kW in UHF band. And the key hardware components including klystron and antenna are being prepared and designed through the collaboration with KWU, KAPRA and SNU.

  3. Development of long pulse RF heating and current drive for H-mode scenarios with metallic walls in WEST

    Energy Technology Data Exchange (ETDEWEB)

    Ekedahl, Annika, E-mail: annika.ekedahl@cea.fr; Bourdelle, Clarisse; Artaud, Jean-François; Bernard, Jean-Michel; Bufferand, Hugo; Colas, Laurent; Decker, Joan; Delpech, Léna; Dumont, Rémi; Goniche, Marc; Helou, Walid; Hillairet, Julien; Lombard, Gilles; Magne, Roland; Mollard, Patrick; Nardon, Eric; Peysson, Yves; Tsitrone, Emmanuelle [CEA, IRFM, F-13108 Saint Paul-lez-Durance (France)

    2015-12-10

    The longstanding expertise of the Tore Supra team in long pulse heating and current drive with radiofrequency (RF) systems will now be exploited in the WEST device (tungsten-W Environment in Steady-state Tokamak) [1]. WEST will allow an integrated long pulse tokamak programme for testing W-divertor components at ITER-relevant heat flux (10-20 MW/m{sup 2}), while treating crucial aspects for ITER-operation, such as avoidance of W-accumulation in long discharges, monitoring and control of heat fluxes on the metallic plasma facing components (PFCs) and coupling of RF waves in H-mode plasmas. Scenario modelling using the METIS-code shows that ITER-relevant heat fluxes are compatible with the sustainment of long pulse H-mode discharges, at high power (up to 15 MW / 30 s at I{sub P} = 0.8 MA) or high fluence (up to 10 MW / 1000 s at I{sub P} = 0.6 MA) [2], all based on RF heating and current drive using Ion Cyclotron Resonance Heating (ICRH) and Lower Hybrid Current Drive (LHCD). This paper gives a description of the ICRH and LHCD systems in WEST, together with the modelling of the power deposition of the RF waves in the WEST-scenarios.

  4. Current and future capabilities of the neutron reflectometer MIRROR at Oak Ridge National Laboratory's High Flux Isotope Reactor

    Science.gov (United States)

    Hamilton, W. A.; Smith, G. S.; Taylor, G. B.; Larkins, B. M.; Porcar, L.

    2006-11-01

    The peripatetic ORNL HFIR Center for Neutron Scattering reflectometer instrument MIRROR has recently been re-installed in an interim beam line position in the reactor beam room. In 2006 an upgraded version of the instrument will move to a high intensity guide hall position fed by the new HFIR cold source. In this short note, we present some aspects of current instrument operation-particularly with respect to data reduction from the instrument's linear reflection plane detector-with examples of ongoing research and analysis, and a brief outline of the expected capabilities of the fully upgraded guide hall instrument.

  5. Digitally Controlled Current Source Amplifiers for Power Converter Gate Drive Units

    OpenAIRE

    Scheele, Mathias

    2013-01-01

    Within this project, performance differences of 3.3 kV / 1500 A IGBT modules of the same type, but of different production batches are being investigated while the modules are being driven by the gate drive units of Bombardier Transportation. The results will be compared to measurements of a reference module. Devices of two different manufacturers were used. Results show that the deviations in terms of dI/dt, dV/dt and losses are generally very small. However, the IGBTs react differently if a...

  6. REACTIVE CURRENT OF AN INDUCTION ELECTRIC DRIVES WITH THYRISTOR VOLTAGE REGULATOR

    Directory of Open Access Journals (Sweden)

    J.V. Kovalova

    2014-12-01

    Full Text Available A model for a separation of reactive constituent from current of idling of an induction motor at its feed from a thyristor voltage regulator in the dependences on the control angle of thyristors is developed. As a result of modeling, dependence of relative reactive current which is approximated by formula for calculation of effective current of reactive constituent of nonsinusoidal current is obtained.

  7. THE IDEA IS TO USEMODIS IN CONJUNCTION WITH THE CURRENT LIMITED LANDSAT CAPABILITY, COMMERCIAL SATELLITES, ANDUNMANNED AERIAL VEHICLES (UAV), IN A MULTI-STAGE APPROACH TO MEET EPA INFORMATION NEEDS.REMOTE SENSING OVERVIEW: EPA CAPABILITIES, PRIORITY AGENCY APPLICATIONS, SENSOR/AIRCRAFT CAPABILITIES, COST CONSIDERATIONS, SPECTRAL AND SPATIAL RESOLUTIONS, AND TEMPORAL CONSIDERATIONS

    Science.gov (United States)

    EPA remote sensing capabilities include applied research for priority applications and technology support for operational assistance to clients across the Agency. The idea is to use MODIS in conjunction with the current limited Landsat capability, commercial satellites, and Unma...

  8. THE IDEA IS TO USEMODIS IN CONJUNCTION WITH THE CURRENT LIMITED LANDSAT CAPABILITY, COMMERCIAL SATELLITES, ANDUNMANNED AERIAL VEHICLES (UAV), IN A MULTI-STAGE APPROACH TO MEET EPA INFORMATION NEEDS.REMOTE SENSING OVERVIEW: EPA CAPABILITIES, PRIORITY AGENCY APPLICATIONS, SENSOR/AIRCRAFT CAPABILITIES, COST CONSIDERATIONS, SPECTRAL AND SPATIAL RESOLUTIONS, AND TEMPORAL CONSIDERATIONS

    Science.gov (United States)

    EPA remote sensing capabilities include applied research for priority applications and technology support for operational assistance to clients across the Agency. The idea is to use MODIS in conjunction with the current limited Landsat capability, commercial satellites, and Unma...

  9. Drought Predictability and Prediction in a Changing Climate: Assessing Current Predictive Knowledge and Capabilities, User Requirements and Research Priorities

    Science.gov (United States)

    Schubert, Siegfried

    2011-01-01

    Drought is fundamentally the result of an extended period of reduced precipitation lasting anywhere from a few weeks to decades and even longer. As such, addressing drought predictability and prediction in a changing climate requires foremost that we make progress on the ability to predict precipitation anomalies on subseasonal and longer time scales. From the perspective of the users of drought forecasts and information, drought is however most directly viewed through its impacts (e.g., on soil moisture, streamflow, crop yields). As such, the question of the predictability of drought must extend to those quantities as well. In order to make progress on these issues, the WCRP drought information group (DIG), with the support of WCRP, the Catalan Institute of Climate Sciences, the La Caixa Foundation, the National Aeronautics and Space Administration, the National Oceanic and Atmospheric Administration, and the National Science Foundation, has organized a workshop to focus on: 1. User requirements for drought prediction information on sub-seasonal to centennial time scales 2. Current understanding of the mechanisms and predictability of drought on sub-seasonal to centennial time scales 3. Current drought prediction/projection capabilities on sub-seasonal to centennial time scales 4. Advancing regional drought prediction capabilities for variables and scales most relevant to user needs on sub-seasonal to centennial time scales. This introductory talk provides an overview of these goals, and outlines the occurrence and mechanisms of drought world-wide.

  10. Persistent sodium current drives conditional pacemaking in CA1 pyramidal neurons under muscarinic stimulation.

    Science.gov (United States)

    Yamada-Hanff, Jason; Bean, Bruce P

    2013-09-18

    Hippocampal CA1 pyramidal neurons are normally quiescent but can fire spontaneously when stimulated by muscarinic agonists. In brain slice recordings from mouse CA1 pyramidal neurons, we examined the ionic basis of this activity using interleaved current-clamp and voltage-clamp experiments. Both in control and after muscarinic stimulation, the steady-state current-voltage curve was dominated by inward TTX-sensitive persistent sodium current (I(NaP)) that activated near -75 mV and increased steeply with depolarization. In control, total membrane current was net outward (hyperpolarizing) near -70 mV so that cells had a stable resting potential. Muscarinic stimulation activated a small nonselective cation current so that total membrane current near -70 mV shifted to become barely net inward (depolarizing). The small depolarization triggers regenerative activation of I(NaP), which then depolarizes the cell from -70 mV to spike threshold. We quantified the relative contributions of I(NaP), hyperpolarization-activated cation current (I(h)), and calcium current to pacemaking by using the cell's own firing as a voltage command along with specific blockers. TTX-sensitive sodium current was substantial throughout the entire interspike interval, increasing as the membrane potential approached threshold, while both Ih and calcium current were minimal. Thus, spontaneous activity is driven primarily by activation of I(NaP) in a positive feedback loop starting near -70 mV and providing increasing inward current to threshold. These results show that the pacemaking "engine" from I(NaP) is an inherent property of CA1 pyramidal neurons that can be engaged or disengaged by small shifts in net membrane current near -70 mV, as by muscarinic stimulation.

  11. Optimal state feedback control of brushless direct-current motor drive systems based on Lyapunov stability criterion

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    This paper develops a unified methodology for a real-time speed control of brushless direct-current motor drive systems in the presence of measurement noise and load torque disturbance. First, the mathematical model and hardware structure of system is established. Next, an optimal state feed back controller using the Kalman filter state estimation technique is derived.This is followed by an adaptive control algorithm to compensate for the effects of noise and disturbance. Those two algorithms working together can provide a very-high-speed regulation and dynamic response over a wide range of operating conditions.Simulated responses are presented to highlight the effectiveness of the proposed control strategy.

  12. Berry{close_quote}s phase and a possible new topological current drive in certain weak link superconducting systems

    Energy Technology Data Exchange (ETDEWEB)

    Gaitan, F.; Shenoy, S.R. [International Center for Theoretical Physics, P. O. Box 586, Miramare, 34100 Trieste (Italy)

    1996-06-01

    We examine the consequences of Berry{close_quote}s phase for the dynamics of Josephson junctions and junction arrays in which moving vortices are present. For both a large annular Josephson junction and a 2D junction array, Berry{close_quote}s phase produces a new current drive in the superconducting phase dynamics of these weak link systems. This Berry phase effect is shown to be physically inequivalent to a known effect in junction arrays associated with the Aharonov-Casher phase. {copyright} {ital 1996 The American Physical Society.}

  13. Complex state variable- and disturbance observer-based current controllers for AC drives

    DEFF Research Database (Denmark)

    Dal, Mehmet; Teodorescu, Remus; Blaabjerg, Frede

    2013-01-01

    , extracted by a disturbance observer and then injected into the current controller. In this study, a revised version of a disturbance observer-based controller and a well known complex variable model-based design with a single set of complex pole are compared in terms of design aspects and performance...... of the parameter and the cross-coupling effect. Moreover, it provides a better performance, smooth and low noisy operation with respect to the complex variable controller....... of the stator current. In order to improve the current control performance an alternative current control strategy was proposed previously aiming to avoid the undesired cross-coupling and non-linearities between the state variables. These effects are assumed as disturbances arisen in the closed-loop path...

  14. Gandhi and the Environmental Consequences of the Current Drive to Industrialization and Modernization.

    Science.gov (United States)

    Sinha, Rajiv K.

    1993-01-01

    Discusses Gandhi's developmental philosophy that small is beautiful in relation to current issues in ecological conservation. Issues include environmental education, economic development, rural development, natural farming, and Gandhi's philosophy among Western nations. (MDH)

  15. Current understanding of the driving mechanisms for spatiotemporal variations of atmospheric speciated mercury: a review

    Science.gov (United States)

    Mao, Huiting; Cheng, Irene; Zhang, Leiming

    2016-10-01

    Atmospheric mercury (Hg) is a global pollutant and thought to be the main source of mercury in oceanic and remote terrestrial systems, where it becomes methylated and bioavailable; hence, atmospheric mercury pollution has global consequences for both human and ecosystem health. Understanding of spatial and temporal variations of atmospheric speciated mercury can advance our knowledge of mercury cycling in various environments. This review summarized spatiotemporal variations of total gaseous mercury or gaseous elemental mercury (TGM/GEM), gaseous oxidized mercury (GOM), and particulate-bound mercury (PBM) in various environments including oceans, continents, high elevation, the free troposphere, and low to high latitudes. In the marine boundary layer (MBL), the oxidation of GEM was generally thought to drive the diurnal and seasonal variations of TGM/GEM and GOM in most oceanic regions, leading to lower GEM and higher GOM from noon to afternoon and higher GEM during winter and higher GOM during spring-summer. At continental sites, the driving mechanisms of TGM/GEM diurnal patterns included surface and local emissions, boundary layer dynamics, GEM oxidation, and for high-elevation sites mountain-valley winds, while oxidation of GEM and entrainment of free tropospheric air appeared to control the diurnal patterns of GOM. No pronounced diurnal variation was found for Tekran measured PBM at MBL and continental sites. Seasonal variations in TGM/GEM at continental sites were attributed to increased winter combustion and summertime surface emissions, and monsoons in Asia, while those in GOM were controlled by GEM oxidation, free tropospheric transport, anthropogenic emissions, and wet deposition. Increased PBM at continental sites during winter was primarily due to local/regional coal and wood combustion emissions. Long-term TGM measurements from the MBL and continental sites indicated an overall declining trend. Limited measurements suggested TGM/GEM increasing from the

  16. Current-Sensing and Voltage-Feedback Driving Method for Large-Area High-Resolution Active Matrix Organic Light Emitting Diodes

    Science.gov (United States)

    In, Hai‑Jung; Choi, Byong‑Deok; Chung, Ho‑Kyoon; Kwon, Oh‑Kyong

    2006-05-01

    There is the problem of picture quality nonuniformity due to thin film transistor (TFT) characteristic variations throughout a panel of large-area high-resolution active matrix organic light emitting diodes. The current programming method could solve this issue, but it also requires very long charging time of a data line at low gray shades. Therefore, we propose a new driving method and a pixel circuit with emission-current sensing and feedback operation in order to resolve these problems. The proposed driving method and pixel circuit successfully compensate threshold voltage and mobility variations of TFTs and overcome the data line charging problem. Simulation results show that emission current deviations of the proposed driving method are less than 1.7% with ± 10.0% mobility and ± 0.3 V threshold voltage variations of pixel-driving TFTs, which means the proposed driving method is applicable to large-area high-resolution applications.

  17. An Overview of Current Capabilities and Research Activities in the Airspace Operations Laboratory at NASA Ames Research Center

    Science.gov (United States)

    Prevot, Thomas; Smith, Nancy M.; Palmer, Everett; Callantine, Todd; Lee, Paul; Mercer, Joey; Homola, Jeff; Martin, Lynne; Brasil, Connie; Cabrall, Christopher

    2014-01-01

    The Airspace Operations Laboratory at NASA Ames conducts research to provide a better understanding of roles, responsibilities, and requirements for human operators and automation in future air traffic management (ATM) systems. The research encompasses developing, evaluating, and integrating operational concepts and technologies for near-, mid-, and far-term air traffic operations. Current research threads include efficient arrival operations, function allocation in separation assurance and efficient airspace and trajectory management. The AOL has developed powerful air traffic simulation capabilities, most notably the Multi Aircraft Control System (MACS) that is used for many air traffic control simulations at NASA and its partners in government, academia and industry. Several additional NASA technologies have been integrated with the AOL's primary simulation capabilities where appropriate. Using this environment, large and small-scale system-level evaluations can be conducted to help make near-term improvements and transition NASA technologies to the FAA, such as the technologies developed under NASA's Air Traffic Management Demonstration-1 (ATD-1). The AOL's rapid prototyping and flexible simulation capabilities have proven a highly effective environment to progress the initiation of trajectory-based operations and support the mid-term implementation of NextGen. Fundamental questions about accuracy requirements have been investigated as well as realworld problems on how to improve operations in some of the most complex airspaces in the US. This includes using advanced trajectory-based operations and prototype tools for coordinating arrivals to converging runways at Newark airport and coordinating departures and arrivals in the San Francisco and the New York metro areas. Looking beyond NextGen, the AOL has started exploring hybrid human/automation control strategies as well as highly autonomous operations in the air traffic control domain. Initial results

  18. High-Speed Current dq PI Controller for Vector Controlled PMSM Drive

    Directory of Open Access Journals (Sweden)

    Mohammad Marufuzzaman

    2014-01-01

    Full Text Available High-speed current controller for vector controlled permanent magnet synchronous motor (PMSM is presented. The controller is developed based on modular design for faster calculation and uses fixed-point proportional-integral (PI method for improved accuracy. Current dq controller is usually implemented in digital signal processor (DSP based computer. However, DSP based solutions are reaching their physical limits, which are few microseconds. Besides, digital solutions suffer from high implementation cost. In this research, the overall controller is realizing in field programmable gate array (FPGA. FPGA implementation of the overall controlling algorithm will certainly trim down the execution time significantly to guarantee the steadiness of the motor. Agilent 16821A Logic Analyzer is employed to validate the result of the implemented design in FPGA. Experimental results indicate that the proposed current dq PI controller needs only 50 ns of execution time in 40 MHz clock, which is the lowest computational cycle for the era.

  19. A Review of Voltage and Current Signature Diagnosis in Industrial Drives

    Directory of Open Access Journals (Sweden)

    K. Vinoth Kumar

    2011-09-01

    Full Text Available This paper presents the review of identify the different types of faults in the induction motor during online condition by using current and voltage signature analysis. Special attention is focused on the effect of both space distribution of rotor breakage and rotor dis-symmetry on the mechanism of generation of diagnosis signatures with the consideration of voltage supply unbalance and speed ripples. A comparison is made between the voltage signature analysis and current signature analysis. Keywords: Fault diagnosis, Induction motor, rotor breakage, MCSA, Motor voltage signature analysis (MVSA.

  20. Performance Evaluation of Electronic Inductor-Based Adjustable Speed Drives with Respect to Line Current Interharmonics

    DEFF Research Database (Denmark)

    Soltani, Hamid; Davari, Pooya; Zare, Firuz;

    2017-01-01

    attractive due to its improved harmonic performance compared to a conventional ASD. In this digest, the input currents of the EI-based ASD are investigated and compared with the conventional ASDs with respect to interharmonics, which is an emerging power quality topic. First, the main causes...

  1. On the merits of heating and current drive for tearing mode stabilization

    NARCIS (Netherlands)

    De Lazzari, D.; Westerhof, E.

    2009-01-01

    Neoclassical tearing modes (NTMs) are magnetohydrodynamic modes that can limit the performance of high beta discharges in a tokamak, leading eventually to a plasma disruption. A NTM is sustained by the perturbation of the 'bootstrap' current, which is a consequence of the pressure flatteni

  2. Nonlinear MHD simulation of current drive by multi-pulsed coaxial helicity injection in spherical torus

    Science.gov (United States)

    Kanki, Takashi; Nagata, Masayoshi; Kagei, Yasuhiro

    2011-10-01

    The dynamics of structures of magnetic field, current density, and plasma flow generated during multi-pulsed coaxial helicity injection in spherical torus is investigated by 3-D nonlinear MHD simulations. During the driven phase, the flux and current amplifications occur due to the merging and magnetic reconnection between the preexisting plasma in the confinement region and the ejected plasma from the gun region involving the n = 1 helical kink distortion of the central open flux column (COFC). Interestingly, the diamagnetic poloidal flow which tends toward the gun region is then observed due to the steep pressure gradients of the COFC generated by ohmic heating through an injection current winding around the inboard field lines, resulting in the formation of the strong poloidal flow shear at the interface between the COFC and the core region. This result is consistent with the flow shear observed in the HIST. During the decay phase, the configuration approaches the axisymmetric MHD equilibrium state without flow because of the dissipation of magnetic fluctuation energy to increase the closed flux surfaces, suggesting the generation of ordered magnetic field structure. The parallel current density λ concentrated in the COFC then diffuses to the core region so as to reduce the gradient in λ, relaxing in the direction of the Taylor state.

  3. The simulation of hard x-ray images obtained during lower hybrid current drive on PBX-M

    Energy Technology Data Exchange (ETDEWEB)

    Goeler, S. von; Fishman, H.; Ignat, D. [and others

    1994-10-01

    During lower hybrid current drive on PBX-M suprathermal electrons in the 30 to 150 keV range are generated. These electrons emit hard X-ray bremsstrahlung in collisions with plasma ions; the radiation creates images in a hard X-ray pinhole camera. In order to interpret the hard X-ray images, a computer simulation code has been written, the PBXRAY code. It represents an extension of the STEVENS code that calculates the free-free and free-bound radiation for non-Maxwellian relativistic electron tail distributions. The PBXRAY code provides the chord integration in the bean-shaped plasma geometry on PBX-M and integrates over photon energy. The simulations show that the location of the suprathermal electrons can be determined with an accuracy of approximately two centimeters in the plasma. In particular, the authors analyzed discharges whose characteristic ``hollow`` images indicate off-axis LH current drive. A comparison of images taken with different absorber foils reveals that the suprathermal electrons have less than 150 keV parallel energy for the hollow discharges.

  4. Comparison of Output Current Ripple in Single and Dual Three-Phase Inverters for Electric Vehicle Motor Drives

    Directory of Open Access Journals (Sweden)

    Jelena Loncarski

    2015-04-01

    Full Text Available The standard solution for the traction system in battery powered electric vehicles (EVs is a two-level (2L inverter feeding a three-phase motor. A simple and effective way to achieve a three-level (3L inverter in battery-supplied electric vehicles consists of using two standard three-phase 2L inverters with the open-end winding connection of standard three-phase ac motors. The 3L inverter solution can be usefully adopted in EVs since it combines several benefits such as current ripple reduction, increment of phase motor voltage with limited voltage ratings of the two battery banks, improvement in system reliability, etc. The reduction in current ripple amplitude is particularly relevant since it is a source of electromagnetic interference and audio noise from the inverter-motor power connection cables and from the motor itself. By increasing the inverter switching frequency the ripple amplitude is reduced, but the drive efficiency decreases due to the proportionally increased switching losses. In this paper the peak-to-peak ripple amplitude of the dual-2L inverter is evaluated and compared with the corresponding ripple of the single-2L inverter, considering the same voltage and power motor ratings. The ripple analysis is carried out as a function of the modulation index to cover the whole modulation range of the inverter, and the theoretical results are verified with experimental tests carried out by an inverter-motor drive prototype.

  5. Benchmarking of electron cyclotron heating and current drive codes on ITER scenarios within the European Integrated Tokamak Modelling framework

    Directory of Open Access Journals (Sweden)

    Peysson Y.

    2012-09-01

    Full Text Available Electron cyclotron resonance heating (ECRH and electron cyclotron current drive (ECCD are used to heat the plasma, to tailor the current profiles and to achieve different operating regimes of tokamak plasmas. Plasmas with ECRH/ECCD are characterized by non-thermal electrons, which cannot be described by a Maxwellian distribution. Non-thermal electrons are also generated during MHD activity, like sawteeth crashes. Quantifying the non-thermal electron distribution is therefore a key for understanding EC heated fusion plasmas. For this purpose a vertical electron cyclotron emission (V-ECE diagnostic is being installed at TCV. The diagnostic layout, the calibration, the analysis technique for data interpretation, the physics potentials and limitations are discussed.

  6. Minimization and identification of conducted emission bearing current in variable speed induction motor drives using PWM inverter

    Indian Academy of Sciences (India)

    A Ramachandran; M Channa Reddy; Ranjan Moodithaya

    2008-10-01

    The recent increase in the use of speed control of ac induction motor for variable speed drive using pulse width modulation (PWM) inverter is due to the advent of modern power electronic devices and introduction of microprocessors. There are many advantages of using ac induction motor for speed control applicatons in process and aerospace industries, but due to fast switching of the modern power electronic devices, the parasitic coupling produces undesirable effects. The undesirable effects include radiated and conducted electromagnetic interference (EMI) which adversely affect nearby computers, electronic/electrical instruments and give rise to the flow of bearing current in the induction motor. Due to the flow of bearing current in the induction motor, electrical discharge machining takes place in the inner race of the bearing which reduces the life of the bearing. In high power converters and inverters, the conducted and radiated emissions become a major concern. In this paper, identification of bearing current due to conducted emission, the measurement of bearing current in a modified induction motor and to minimize the bearing current are discussed. The standard current probe, the standard line impedance stabilization network (LISN)), the electronics interface circuits are used to measure high frequency common mode current, bearing current and to minimize the conducted noise from the system. The LISN will prevent the EMI noise entering the system from the supply source by conductive methods, at the same time prevents the EMI generated if any due to PWM, fast switching in the system, will not be allowed to enter the supply line. For comparing the results with Federal Communications Commission (FCC) and Special Committee on Radio Interference (CISPR) standards, the graphs are plotted with frequency Vs, line voltage in $dB{_\\mu} V$, common mode voltage in $dB{_\\mu} V$ and the bearing current in $dB_{\\mu} A$ with out and with minimizing circuits.

  7. Load Torque Compensator for Model Predictive Direct Current Control in High Power PMSM Drive Systems

    DEFF Research Database (Denmark)

    Preindl, Matthias; Schaltz, Erik

    2010-01-01

    behaviour. It compensates the load torque influence on the speed control setting a feed forward torque value, i.e. current reference value. The benefits are twice. The speed controller reaches immediately the speed reference value avoiding offsets which must be compensated by the weak integrator. Moreover......, a better response to load torque variations which are detected and compensated leading to small speed variations is obtained....

  8. Magnetic ripple and the modeling of lower-hybrid current drive in tokamaks

    Energy Technology Data Exchange (ETDEWEB)

    Peysson, Y.; Arslanbekov, R.; Basiuk, V.; Carrasco, J.; Litaudon, X.; Moreau, D. [Association Euratom-CEA, Centre d`Etudes de Cadarache, 13 - Saint-Paul-lez-Durance (France). Dept. de Recherches sur la Fusion Controlee; Bizarro, J.P. [Instituto Superior Tecnico, Lisbon (Portugal). Lab. de Quimica Organica

    1996-01-01

    Using ray-tracing, a detailed investigation of the lower hybrid (LH) wave propagation in presence of toroidal magnetic field ripple is presented. By coupling ray tracing with a one-dimensional relativistic Fokker-Planck code, simulations of LH experiments have been performed for the Tore Supra tokamak. Taking into account magnetic ripple in LH simulations, a better agreement is found between numerical predictions and experimental observations, such as non-thermal Bremsstrahlung emission, current profile, ripple-induced power losses in local magnetic mirrors, when plasma conditions correspond to the ` `few passes` regime. (author). 47 refs.

  9. Heating and current drive requirements for ideal MHD stability and ITB sustainment in ITER steady state scenarios

    Science.gov (United States)

    Poli, Francesca

    2012-10-01

    Steady state scenarios envisaged for ITER aim at optimizing the bootstrap current, while maintaining sufficient confinement and stability to provide the necessary fusion yield. Non-inductive scenarios will need to operate with Internal Transport Barriers (ITBs) in order to reach adequate fusion gain at typical currents of 9 MA. However, the large pressure gradients associated with ITBs in regions of weak or negative magnetic shear can be conducive to ideal MHD instabilities in a wide range of βN, reducing the no-wall limit. Scenarios are established as relaxed flattop states with time-dependent transport simulations with TSC [1]. Fully non-inductive configurations with current in the range of 7-10 MA and various heating mixes (NB, EC, IC and LH) have been studied against variations of the pressure profile peaking and of the Greenwald fraction. It is found that stable equilibria have qmin> 2 and moderate ITBs at 2/3 of the minor radius [2]. The ExB flow shear from toroidal plasma rotation is expected to be low in ITER, with a major role in the ITB dynamics being played by magnetic geometry. Combinations of H&CD sources that maintain reverse or weak magnetic shear profiles throughout the discharge and ρ(qmin)>=0.5 are the focus of this work. The ITER EC upper launcher, designed for NTM control, can provide enough current drive off-axis to sustain moderate ITBs at mid-radius and maintain a non-inductive current of 8-9MA and H98>=1.5 with the day one heating mix. LH heating and current drive is effective in modifying the current profile off-axis, facilitating the formation of stronger ITBs in the rampup phase, their sustainment at larger radii and larger bootstrap fraction. The implications for steady state operation and fusion performance are discussed.[4pt] [1] Jardin S.C. et al, J. Comput. Phys. 66 (1986) 481[0pt] [2] Poli F.M. et al, Nucl. Fusion 52 (2012) 063027.

  10. Effective variable switching point predictive current control for ac low-voltage drives

    Science.gov (United States)

    Stolze, Peter; Karamanakos, Petros; Kennel, Ralph; Manias, Stefanos; Endisch, Christian

    2015-07-01

    This paper presents an effective model predictive current control scheme for induction machines driven by a three-level neutral point clamped inverter, called variable switching point predictive current control. Despite the fact that direct, enumeration-based model predictive control (MPC) strategies are very popular in the field of power electronics due to their numerous advantages such as design simplicity and straightforward implementation procedure, they carry two major drawbacks. These are the increased computational effort and the high ripples on the controlled variables, resulting in a limited applicability of such methods. The high ripples occur because in direct MPC algorithms the actuating variable can only be changed at the beginning of a sampling interval. A possible remedy for this would be to change the applied control input within the sampling interval, and thus to apply it for a shorter time than one sample. However, since such a solution would lead to an additional overhead which is crucial especially for multilevel inverters, a heuristic preselection of the optimal control action is adopted to keep the computational complexity at bay. Experimental results are provided to verify the potential advantages of the proposed strategy.

  11. Laser-driven Beat-Wave Current Drive in Dense Plasmas with Demo on CTIX

    Science.gov (United States)

    Liu, Fei; Horton, Robert; Hwang, David; Zhu, Ben; Evans, Russell; Hong, Sean; Hsu, Scott

    2010-11-01

    The ability to remotely generate plasma current in dense plasmas hanging freely in vacuum in voluminous amount without obstruction to diagnostics will greatly enhance our ability to study the physics of high energy density plasmas in strong magnetic fields. Plasma current can be generated through nonlinear beat-wave process by launching two intense electromagnetic waves into unmagnetized plasma. Beat-wave acceleration of electrons has been demonstrated in a low-density plasma using microwaves [1]. The proposed PLX experimental facility presently under construction at Los Alamos offers the opportunity to test the method at a density level scalable to the study of HED plasmas. For PLX beat-wave experiments, CO2 lasers will be used as pump waves due to their high power and tunability. For a typical PLX density ne=10^17cm-3, two CO2 lasers can be separately tuned to 9P(28) and 10P(20) to match the 2.84THz plasma frequency. The beat-wave demo experiment will be conducted on CTIX. The laser arrangement is being converted to two independent single lasers. Frequency-tuning methods, optics focusing system and diagnostics system will be discussed. The laser measurements and results of synchronization of two lasers will be presented, and scaling to PLX experiments will be given. [1] Rogers, J. H. and Hwang, D. Q., PRL. v68 p3877 (1992).

  12. Heating, current drive and confinement regimes with the JET ICRH and LHCD systems

    DEFF Research Database (Denmark)

    Jacquinot, J.; Adams, J.M.; Altmann, H.;

    1991-01-01

    During its 1990 operation, 2 large RF systems were available on JET. The Ion Cyclotron Resonance Heating (ICRH) system was equipped with new beryllium screens and with feedback matching systems. Specific impurities generated by ICRH were reduced to negligible levels even in the most stringent H......-mode conditions. A maximum power of 22 MW was coupled to L-mode plasmas. High quality H-modes (tau-E greater-than-or-equal-to 2.5 tau-EG) were achieved using dipole phasing. A new high confinement mode was discovered. It combines the properties of the H-mode regime to the low central diffusivities obtained....... Paradoxically, LHCD induces central heating particularly in combination with ICRH. Finally we present the first observations of the synergistic acceleration of fast electrons by Transit Time Magnetic Pumping (TTMP) (from ICRH) and Electron Landau Damping (ELD) (from LHCD). The synergism generates TTMP current...

  13. FPGA-based voltage and current dual drive system for high frame rate electrical impedance tomography.

    Science.gov (United States)

    Khan, Shadab; Manwaring, Preston; Borsic, Andrea; Halter, Ryan

    2015-04-01

    Electrical impedance tomography (EIT) is used to image the electrical property distribution of a tissue under test. An EIT system comprises complex hardware and software modules, which are typically designed for a specific application. Upgrading these modules is a time-consuming process, and requires rigorous testing to ensure proper functioning of new modules with the existing ones. To this end, we developed a modular and reconfigurable data acquisition (DAQ) system using National Instruments' (NI) hardware and software modules, which offer inherent compatibility over generations of hardware and software revisions. The system can be configured to use up to 32-channels. This EIT system can be used to interchangeably apply current or voltage signal, and measure the tissue response in a semi-parallel fashion. A novel signal averaging algorithm, and 512-point fast Fourier transform (FFT) computation block was implemented on the FPGA. FFT output bins were classified as signal or noise. Signal bins constitute a tissue's response to a pure or mixed tone signal. Signal bins' data can be used for traditional applications, as well as synchronous frequency-difference imaging. Noise bins were used to compute noise power on the FPGA. Noise power represents a metric of signal quality, and can be used to ensure proper tissue-electrode contact. Allocation of these computationally expensive tasks to the FPGA reduced the required bandwidth between PC, and the FPGA for high frame rate EIT. In 16-channel configuration, with a signal-averaging factor of 8, the DAQ frame rate at 100 kHz exceeded 110 frames s (-1), and signal-to-noise ratio exceeded 90 dB across the spectrum. Reciprocity error was found to be for frequencies up to 1 MHz. Static imaging experiments were performed on a high-conductivity inclusion placed in a saline filled tank; the inclusion was clearly localized in the reconstructions obtained for both absolute current and voltage mode data.

  14. Electron Drift Speed And Current-Induced Drive Torques On A Domain Wall

    Science.gov (United States)

    Berger, Luc

    2009-03-01

    It has become fashionable to describe [1] current-induced torques on a DW in terms of an electron drift speed u = - P*j*muB/e*M where muB is the Bohr magneton and M the saturation magnetization. While appropriate for adiabatic torques, this quantity u is misleading and not the best choice in the case of non-adiabatic torques. For example, it leads [2] to beta not equal to alpha, where beta represents the intensity of the non-adiabatic torque, and alpha is the damping parameter. By writing equations of motion for conduction- electron spins in a moving frame where the electron gas is at rest, we find [3] a direct relation between damping and non- adiabatic torques. The correct electron drift speed turns out to be the speed of the frame, and is v = P*j/(n*q) where n and q are the carrier density and charge. It is related to the ordinary Hall constant R0 by v P*R0*j. After substituting v for u in the expression of the non-adiabatic torque, we find that beta = alpha holds now. Because v is larger than u in Permalloy, it can explain better the large current-induced DW speeds found [4] experimentally. In materials where R0> 0 and the carriers are dominantly hole-like, v and u have opposite signs, leading to different predictions for the sense of DW motion. We discuss examples of such materials. 1. G. Tatara and H. Kohno, Phys. Rev. Lett. 92, 086601 (2004). 2. H. Kohno et al., J. Phys. Soc. Japan, 75, 113706 (2006). 3. L. Berger, Phys. Rev. B 75, 174401 (2007). 4. M. Hayashi et al., Phys. Rev. Lett. 98, 037204 (2007).

  15. Pile Driving

    Science.gov (United States)

    1987-01-01

    Machine-oriented structural engineering firm TERA, Inc. is engaged in a project to evaluate the reliability of offshore pile driving prediction methods to eventually predict the best pile driving technique for each new offshore oil platform. Phase I Pile driving records of 48 offshore platforms including such information as blow counts, soil composition and pertinent construction details were digitized. In Phase II, pile driving records were statistically compared with current methods of prediction. Result was development of modular software, the CRIPS80 Software Design Analyzer System, that companies can use to evaluate other prediction procedures or other data bases.

  16. Lower Hybrid Current Drive and Heating for the National Transport Code Collaboration

    Science.gov (United States)

    Ignat, D. W.; Jardin, S. C.; McCune, D. C.; Valeo, E. J.

    2000-10-01

    The Lower hybrid Simulation Code LSC was originally written as a subroutine to the Toroidal Simulation Code TSC (Jardin, Pomphrey, Kessel, et al) and subsequently ported to a subroutine of TRANSP. Modifications to simplify the use of the LSC both as a callable module, and also independently of larger transport codes, and improve the documentation have been undertaken with the goal of installing LSC in the NTCC library. The physical model, which includes ray tracing from a Brambilla spectrum, 1D Fokker-Planck development of the electron distribution, the Karney-Fisch treatment of the electric field, heuristic diffusion of current and power and wall scattering, has not been changed. The computational approach is to suppress or remove from the control of the user numerical parameters such as step size and number of iterations while changing some code to be extremely stable in varied conditions. Essential graphics are now output as gnuplot commands and data for off-line post processing, but the original outputs to sglib are retained as an option. Examples of output are shown.

  17. THEORY OF ELECTROMAGNETIC DRIVE WITH ELEMENTARY PARTICLES CURRENT AND VACUUM POLARIZATION

    Directory of Open Access Journals (Sweden)

    Trunev A. P.

    2016-01-01

    Full Text Available The article discusses a model of rocket motor of electromagnetic type, consisting of a source of electromagnetic radio frequency oscillations and the conical cavity, in which electromagnetic waves are excited. We have created a multi-dimensional transient numerical model describing the process of establishing electromagnetic oscillations in the resonator, taking into account the finite conductivity of the walls. Separately, the standing waves in the cavity with conducting walls have been simulated. It is shown that the oscillations mode in the conducting resonator different from that in an ideal resonator, both in a case of steady and unsteady waves. We have built a dynamic model taking into account the thermal conductivity and electrical conductivity of the walls, waves and particles emission and vacuum polarization. We have also developed a dynamic model enables to optimize a thrust force on a considerable number of parameters without the involvement of the hypotheses about the physics of the phenomenon. We run the optimization of the operating parameters of the device, namely by the excitation frequency, the frequency of the modulating signal, the magnitude of heat losses of electromagnetic energy by thermal radiation in the IR spectrum, the parameters of forced heat transfer and the temperature dependence of the resistance of the material of the cavity walls. It is found that the pulse modulation greatly improves the efficiency of conversion of electromagnetic energy into thrust. The mechanism of formation of traction, adjusting the metrics of space-time, the current contribution of elementary particles, the Yang-Mills and electromagnetic fields is proposed. It is shown that the contribution of the elementary particles in the thrust force is proportional to the electrical conductivity of the system multiplied by Abraham force

  18. Technological and physics assessments on heating and current drive systems for DEMO

    Energy Technology Data Exchange (ETDEWEB)

    Franke, Thomas, E-mail: thomas.franke@efda.org [EFDA Close Support Unit, Boltzmannstr. 2, D-85748 Garching (Germany); Max Planck Institute for Plasma Physics, Boltzmannstr. 2, D-85748 Garching (Germany); Barbato, E. [Unità Tecnica Fusione ENEA, C. R. Frascati, via E. Fermi 45, 00044 Frascati (Roma) (Italy); Bosia, G. [Department of Physics, University of Turin, Via P. Giuria 1, 10125 Turin (Italy); Cardinali, A.; Ceccuzzi, S.; Cesario, R. [Unità Tecnica Fusione ENEA, C. R. Frascati, via E. Fermi 45, 00044 Frascati (Roma) (Italy); Van Eester, D. [Laboratory for Plasma Physics, LPP-ERM/KMS, TEC & Belgian EUROfusion Consortium Partner, Brussels (Belgium); Federici, G. [EFDA Close Support Unit, Boltzmannstr. 2, D-85748 Garching (Germany); Gantenbein, G. [Karlsruhe Institute of Technology (KIT), Association EURATOM-KIT, Kaiserstrasse 12, 76131 Karlsruhe (Germany); Helou, W.; Hillairet, J. [CEA, IRFM, F-13108 Saint-Paul-lez-Durance (France); Jenkins, I. [CCFE, Culham Science Centre, Abingdon OX143DB (United Kingdom); Kazakov, Ye.O. [Laboratory for Plasma Physics, LPP-ERM/KMS, TEC & Belgian EUROfusion Consortium Partner, Brussels (Belgium); Kemp, R. [CCFE, Culham Science Centre, Abingdon OX143DB (United Kingdom); Lerche, E. [Laboratory for Plasma Physics, LPP-ERM/KMS, TEC & Belgian EUROfusion Consortium Partner, Brussels (Belgium); Mirizzi, F. [Unità Tecnica Fusione ENEA, C. R. Frascati, via E. Fermi 45, 00044 Frascati (Roma) (Italy); Noterdaeme, J.-M.; Poli, E. [Max Planck Institute for Plasma Physics, Boltzmannstr. 2, D-85748 Garching (Germany); Porte, L. [Centre de Recherches en Physique des Plasmas, Ecole Polytechnique Fédérale de Lausanne (EPFL), Station 13, CH-1015 Lausanne (Switzerland); Ravera, G.L. [Unità Tecnica Fusione ENEA, C. R. Frascati, via E. Fermi 45, 00044 Frascati (Roma) (Italy); and others

    2015-10-15

    Highlights: • Basic physics requirements of H&CD systems in DEMO have been captured. • The four H&CD systems NBI, EC, IC and LH were analysed to optimize performance. • Novel solutions were studied to overcome the limitations of the present H&CD systems. • RAMI as well as efficiency and optimized design of H&CD systems have been assessed. • Further constraints by remote maintenance or breeding blanket interactions were considered. - Abstract: The physics requirements of the heating and current (H&CD) systems in a Demonstration Fusion Power Plant (DEMO) are often beyond the actual level of design maturity and technology readiness required. The recent EU fusion roadmap advocates a pragmatic approach and favours, for the initial design integration studies, systems to be as much as possible, extrapolated from the ITER experience. To reach the goal of demonstrating the production of electricity in DEMO with a closed fuel cycle by 2050, one must ensure reliability, availability, maintainability, inspectability (RAMI) as well as performance, efficiency and optimized design for the H&CD systems. In the recent Power Plant Physics & Technology (PPP&T) Work Programme, a number of H&CD studies were performed. The four H&CD systems Neutral Beam (NB) Injection, Electron Cyclotron (EC), Ion Cyclotron (IC) and Lower Hybrid (LH) were considered. First, a physics optimization study was made assuming all technologies are available and identifying which parameters are needed to optimize the performance for given plasma parameters. Separately, the (i) technological maturity was considered (e.g. 240 GHz gyrotrons for EC) and (ii) technologies were adapted (e.g. multi-stage depressed collector for EC) or (iii) novel solutions (e.g. photo-neutralization for NB or new antennae concepts for IC) were studied to overcome the limitations of the present H&CD systems with respect to DEMO requirements. Further constraints imposed by remote maintenance or breeding blanket interactions

  19. Sawtooth control using electron cyclotron current drive in the presence of energetic particles in high performance ASDEX Upgrade plasmas

    CERN Document Server

    Chapman, I T; Maraschek, M; McCarthy, P J; Tardini, G

    2013-01-01

    Sawtooth control using steerable electron cyclotron current drive (ECCD) has been demonstrated in ASDEX Upgrade plasmas with a significant population of energetic ions in the plasma core and long uncontrolled sawtooth periods. The sawtooth period is found to be minimised when the ECCD resonance is swept to just inside the q = 1 surface. By utilising ECCD inside q = 1 for sawtooth control, it is possible to avoid the triggering of neoclassical tearing modes, even at significnatly higher pressure than anticipated in the ITER baseline scenario. Operation at 25% higher normalised pressure has been achieved when only modest ECCD power is used for sawtooth control compared to identical discharges without sawtooth control when neo-classical tearing modes are triggered by the sawteeth. Modelling suggests that the destabilisation arising from the change in the local magnetic shear caused by the ECCD is able to compete with the stabilising influence of the energetic particles inside the q = 1 surface.

  20. Non-inductive current built-up by local electron cyclotron heating and current drive with a 28 GHz focused beam on QUEST

    Science.gov (United States)

    Onchi, Takumi; Idei, Hiroshi; Hasegawa, Makoto; Ohwada, Hiroaki; Zushi, Hideki; Hanada, Kazuaki; Kariya, Tsuyoshi; Mishra, Kishore; Shikama, Taichi; Quest Team

    2016-10-01

    The plasma current can be driven solely by injecting electron cyclotron waves (ECWs) in spherical tokamak (ST) configuration. A system of 28 GHz gyrotron (maximum power: 270 kW) is renewed and reinstalled on QUEST. A focused ECW beam, whose diameter is about 5 cm at the second harmonic resonance, is injected for local ECW heating and current drive. The local power density at resonance exceeds 75 MW/m2 at an injection power of 150 kW. The incident ECW polarization can be adjusted employing the phase shifter consisting of two corrugated plates. During 1.25 second pulse of ECH, plasma current is built up to Ip = 70 kA fully non-inductively with a core electron density of ne > 1018 m-3. The closed flux in such ST plasma is determined at the inboard limiter on the center stack. Energetic electrons are also responsible for the pressure and equilibrium. This work is supported by JSPS KAKENHI (15H04231, 15K17800), NIFS Collaboration Research program (NIFS13KUTR085, NIFS11KUTR069, NIFS16KUTR114).

  1. Characteristics of electron cyclotron resonance plasma formed by lower hybrid current drive grill antenna

    Indian Academy of Sciences (India)

    P K Sharma; S L Rao; K Mishra; R G Trivedi; D Bora

    2008-03-01

    A 3.7 GHz system, which is meant for LHCD experiments on ADITYA tokamak, is used for producing ECR discharge. The ECR discharge is produced by setting the appropriate resonance magnetic field of 0.13 T, with hydrogen at a fill pressure of about 5 × 10-5 Torr. The RF powe r, up to 10 kW (of which ∼ 50% is reflected back), with a typical pulse length of 50 ms, is injected into the vacuum chamber of the ADITYA tokamak by a LHCD grill antenna and is used for plasma formation. The average coupled RF power density (the RF power/a typical volume of the plasma) is estimated to be ∼ 5 kW/m3. When the ECR appears inside the tokamak chamber for the given pumping frequency ( = 3.7 GHz) a plasma with a density () ∼ 4 × 1016 m-3 and electron temperature ∼ 8 eV is produced. The density and temperature during the RF pulse are measured by sets of Langmuir probes, located toroidally, on either side of the antenna. signals are also monitored to detect ionization. An estimate of density and temperature based on simple theoretical calculation agrees well with our experimental measurements. The plasma produced by the above mechanism is further used to characterize the ECR-assisted low voltage Ohmic start-up discharges. During this part of the experiments, Ohmic plasma is formed using capacitor banks. The plasma loop voltage is gradually decreased, till the discharge ceases to form. The same is repeated in the presence of ECR-formed plasma (RF pre-ionization), formed 10 ms prior to the loop voltage. We have observed that (with LHCD-induced) ECR-assisted Ohmic start-up discharges is reliably and repeatedly obtained with reduced loop voltage requirement and breakdown time decreases substantially. The current ramp-up rates also decrease with reduced loop voltage operation. These studies established that ECR plasma formed with LHCD system exhibits similar characteristics as reported earlier by dedicated ECR systems. This experiment also addresses the issue of whether ECR plasma

  2. Historical processes and contemporary ocean currents drive genetic structure in the seagrass Thalassia hemprichii in the Indo-Australian Archipelago.

    Science.gov (United States)

    Hernawan, Udhi E; van Dijk, Kor-Jent; Kendrick, Gary A; Feng, Ming; Biffin, Edward; Lavery, Paul S; McMahon, Kathryn

    2017-02-01

    Understanding spatial patterns of gene flow and genetic structure is essential for the conservation of marine ecosystems. Contemporary ocean currents and historical isolation due to Pleistocene sea level fluctuations have been predicted to influence the genetic structure in marine populations. In the Indo-Australian Archipelago (IAA), the world's hotspot of marine biodiversity, seagrasses are a vital component but population genetic information is very limited. Here, we reconstructed the phylogeography of the seagrass Thalassia hemprichii in the IAA based on single nucleotide polymorphisms (SNPs) and then characterized the genetic structure based on a panel of 16 microsatellite markers. We further examined the relative importance of historical isolation and contemporary ocean currents in driving the patterns of genetic structure. Results from SNPs revealed three population groups: eastern Indonesia, western Indonesia (Sunda Shelf) and Indian Ocean; while the microsatellites supported five population groups (eastern Indonesia, Sunda Shelf, Lesser Sunda, Western Australia and Indian Ocean). Both SNPs and microsatellites showed asymmetrical gene flow among population groups with a trend of southwestward migration from eastern Indonesia. Genetic diversity was generally higher in eastern Indonesia and decreased southwestward. The pattern of genetic structure and connectivity is attributed partly to the Pleistocene sea level fluctuations modified to a smaller level by contemporary ocean currents.

  3. Investigation of Line Current Harmonics in Cascaded Multi-level Inverter Based Induction Motor Drive and an Adaptive On-line Selective Current Harmonic Elimination Algorithm

    Directory of Open Access Journals (Sweden)

    P. Avirajamanjula

    2015-03-01

    Full Text Available Multilevel Inverters (MLIs have drawn increasing attention in numerous applications, especially in drives, distributed energy resources area, utility etc. MLIs have the ability to synthesize a near sinusoidal output voltage wave with minimal Total Harmonic Distortion (THD in low frequency switching. Even though they offer lower THD, the presence of lower order harmonics is objectionable and harmonics elimination in Multilevel Inverters (MLIs has been receiving immense attention for the past few decades. Existing Selective Harmonic Elimination (SHE techniques can eliminate the objectionable lower order voltage harmonics with low switching frequency by solving the Fourier non-linear transcendental equations of the output voltage. The line current harmonics has a direct role to play on the magneto-motive force and results in increase of mismatching of air-gap permeance, vibrations, acoustic noise etc. This study proposes Normalized Least Mean Squares (NLMS algorithm based scheme to eliminate the selected dominant harmonics in load current using only the knowledge of the frequencies to be eliminated. The algorithm is simulated using MATLAB/SIMULINK tool for a three-phase VSI to eliminate the fifth and seventh harmonics. The informative simulation results verify the validity and effectiveness of the proposed algorithm. The system performance is analyzed based on the simulation results considering Total Harmonic Distortion (THD, magnitude of eliminated harmonics and frequency spectrum.

  4. Design of Current Controller in Servo Drive%伺服驱动电流调节器的设计

    Institute of Scientific and Technical Information of China (English)

    游帅; 马钧华

    2012-01-01

    This paper presented a design method of current controller in servo drive. On hardware design, three current sensors, LTS25-NP, ACS7xx, HCPL-7840 and their interface circuit with DSP's AD input were introduced, and these three current sensors can perform well to meet the demands of accuracy and speed in current sampling circuit. On software design, according to simulation, the principles of adjusting PI controller parameters were discussed. The results of the simulations show that good initial PI parameters can he calculated through the motor parameters, thus lay the foundation for experiment tuning. [Ch,8 fig. 1 tab. 10 ref. ]%介绍了伺服驱动中电流调节器的设计方法.在硬件上给出LTS25-NP,ACS7xx,HCPL-7840 3种电流采样器件的工作原理、性能指标和DSP的接口设计,可知3种器件可以满足不同的电流采样精度与速度的要求.在软件上,利用仿真得到电流调节器PI参数计算方法,并介绍实验整定方法.仿真结果表明,通过电机的参数可以计算得到PI电流调节器良好的初始参数,为实验整定做基础.

  5. Direct Drive and Eddy Current Septa Magnet Designs for CERN’s PSB Extraction at 2 GeV

    CERN Multimedia

    Szoke, Zsolt; Balhan, Bruno; Baud, Cedric; Borburgh, Jan; Hourican, Michael; Masson, Thierry; Prost, Antoine

    2015-01-01

    In the framework of the LIU project, new septa magnets have been designed between CERN’s PS Booster (PSB) extraction and PS injection. The upgraded devices are to deal with the increased beam energy from 1.4 GeV to 2 GeV at extraction of the PSB. The direct drive recombination septa in the PSB transfer line to the PS, the eddy current PS injection septum together with a bumper at injection have been investigated using finite element software. For the recombination magnets an increase in magnet length is sufficient to obtain the required deflection; however, for the PS injection elements a more novel solution is necessary to also achieve increased robustness to extend the expected lifetime of the pulsed device. The injection septum will share the same vacuum vessel with an injection bumper and both magnets will be located adjacent to each other. The new PS injection magnet will be the first septum operated at CERN based on eddy current technology. The magnetic modelling of the devices, the comparison of the ...

  6. Two-way shape memory effect and alternating current driving characteristics of a TiNi alloy spring

    Institute of Scientific and Technical Information of China (English)

    WANG Zhiguo; ZU Xiaotao

    2004-01-01

    Two-way shape memory effect (TWSME) was induced into the TiNi shape memory alloys (SMAs) spring by thermomechanical training after annealing treatment, which has promising application in micro-actuating fields. The TWSME spring can contract upon heating and extend upon cooling. The results show that there is an increase of the recovery ratio up to a maximum TWSME of 45%. During the training procedure, transformation temperatures and hysteresis were measured by different scanning calorimetry (DSC). The results show that As (reverse transformation start temperature) and Af (revere transformation finish temperature) shift to lower temperature after training. The intervals of Af-As and Ms-Mr (Ms and Mf are the martensite start and finish temperatures, respectively) increase and the heat of transformation decreases after training. The electrothermal driving characteristics of the TWSME springs were also investigated with alternating current density of 3.2-14.7 A/mm2. It is found that the time response and the maximum contraction ratio greatly depend on the magnitude of the electrical current density.

  7. submitter Direct Drive and Eddy Current Septa Magnet Designs for CERN's PSB Extraction at 2 GeV

    CERN Document Server

    Szoke, Z; Balhan, B; Baud, C; Borburgh, J; Hourican, M; Masson, T; Prost, A

    2016-01-01

    In the framework of the LIU project, new septa magnets have been designed between CERN's PS booster (PSB) extraction and PS injection. The upgraded devices are to deal with the increased beam energy from 1.4 to 2 GeV at extraction of the PSB. The direct drive recombination septa in the PSB transfer line to the PS and the eddy current PS injection septum together with a bumper at injection have been investigated using finite-element software. For the recombination magnets, an increase in magnet length is sufficient to obtain the required deflection; however, for the PS injection elements, a more novel solution is necessary to also achieve increased robustness to extend the expected lifetime of the pulsed device. The injection septum will share the same vacuum vessel with an injection bumper, and both magnets will be located adjacent to each other. The new PS injection magnet will be the first septum operated at CERN based on eddy current technology. The magnetic modeling of the devices, the comparison of the p...

  8. Universal Drive Train Facility

    Data.gov (United States)

    Federal Laboratory Consortium — This vehicle drive train research facility is capable of evaluating helicopter and ground vehicle power transmission technologies in a system level environment. The...

  9. Control algorithm for the inverter fed induction motor drive with DC current feedback loop based on principles of the vector control

    Energy Technology Data Exchange (ETDEWEB)

    Vuckovic, V.; Vukosavic, S. (Electrical Engineering Inst. Nikola Tesla, Viktora Igoa 3, Belgrade, 11000 (Yugoslavia))

    1992-01-01

    This paper brings out a control algorithm for VSI fed induction motor drives based on the converter DC link current feedback. It is shown that the speed and flux can be controlled over the wide speed and load range quite satisfactorily for simpler drives. The base commands of both the inverter voltage and frequency are proportional to the reference speed, but each of them is further modified by the signals derived from the DC current sensor. The algorithm is based on the equations well known from the vector control theory, and is aimed to obtain the constant rotor flux and proportionality between the electrical torque, the slip frequency and the active component of the stator current. In this way, the problems of slip compensation, Ri compensation and correction of U/f characteristics are solved in the same time. Analytical considerations and computer simulations of the proposed control structure are in close agreement with the experimental results measured on a prototype drive.

  10. UGV Interoperability Profile (IOP) Capabilities Plan for Version 0

    Science.gov (United States)

    2011-03-11

    tied to the waypoint plan execution state machine model . This capability is applicable to the BN driving mode. Other Guidance: Current JAUS...the correct range. Limitations and Constraints: This capability will be largely tied to the leader/follower execution state machine model . This

  11. 大型带式输送机驱动能力校核计算%Calculation Method for Drive Capability of Large Belt Conveyor

    Institute of Scientific and Technical Information of China (English)

    张建军; 许宁; 赵炎

    2014-01-01

    With the development direction of long distance , large capacity and large angle of belt conveyor , the drive ability is becoming more important.If the drive ability can′t meet the needs of the actual use, the performance of the conveyor belt will greatly discount and cause great waste.A method of calculating the required motor power is introduced, according to the actual installation condition and performance requirements of the belt conveyor .The drive ability is checked whether meet the re-quirements by comparing with the total power of the motors.BH11-1 of Shenhua Huanghua Harbor, for example, the above calculation is verified.%随着带式输送机向长运距、大运载能力、大倾角的方向发展,对其驱动能力的要求也越来越高,如果驱动能力不能满足实际使用需要,输送带的性能将大打折扣,造成很大浪费。从驱动功率角度入手,详细介绍了一种根据带式输送机的实际安装条件和使用性能要求计算驱动电机所需功率的方法。将其与现场安装的电机总功率进行比较,验证驱动能力并以神华黄骅港务公司BH11-1皮带机为例,对上述计算进行了验证。

  12. Development of a high power wideband polarizer for electron cyclotron current drive system in JT-60SA

    Energy Technology Data Exchange (ETDEWEB)

    Saigusa, Mikio, E-mail: saigusa@mx.ibaraki.ac.jp [Ibaraki University, Hitachi, Ibaraki 316-8511 (Japan); Oyama, Gaku; Matsubara, Fumiaki; Takii, Keita; Sai, Takuma [Ibaraki University, Hitachi, Ibaraki 316-8511 (Japan); Kobayashi, Takayuki; Moriyama, Shinichi [Japan Atomic Energy Agency, Naka, Ibaraki 311-0193 (Japan)

    2015-10-15

    Highlights: • We developed a new wideband polarizer for JT-60SA ECCD system. • The wideband polarizer is optimized for dual frequency gyrotrons (110 and 138 GHz) in JT-60SA. • The wideband polarization properties were verified at cold tests. • The preliminary high power tests have been carried out at 0.25 MW, 3 s at 110 GHz. - Abstract: A wideband polarizer consisting of a polarization twister and a circular polarizer has been developed for an electron cyclotron current driving system in JT-60SA, where the output frequencies of a dual frequency gyrotron for JT-60SA are 110 and 138 GHz. The groove depths are optimized for the dual frequencies by numerical simulations using a FDTD method and cold test results. The polarization properties of a mock-up polarizer are measured at the dual frequencies in cold tests. The cold test results suggest that all practical polarizations for ECCD experiments can be achieved at the dual frequencies. The prototype polarization twister has been tested up to 0.25 MW during 3 s at the frequency of 110 GHz.

  13. Non-linear effects in electron cyclotron current drive applied for the stabilization of neoclassical tearing modes

    CERN Document Server

    Ayten, B

    2013-01-01

    Due to the smallness of the volumes associated with the flux surfaces around the O-point of a magnetic island, the electron cyclotron power density applied inside the island for the stabilization of neoclassical tearing modes (NTMs) can exceed the threshold for non-linear effects as derived previously by Harvey et al, Phys. Rev. Lett. 62 (1989) 426. We study the non-linear electron cyclotron current drive (ECCD) efficiency through bounce-averaged, quasi-linear Fokker-Planck calculations in the magnetic geometry as created by the islands. The calculations are performed for the parameters of a typical NTM stabilization experiment on ASDEX Upgrade. A particular feature of these experiments is that the rays of the EC wave beam propagate tangential to the flux surfaces in the power deposition region. The calculations show significant non-linear effects on the ECCD efficiency, when the ECCD power is increased from its experimental value of 1 MW to a larger value of 4 MW. The nonlinear effects are largest in case of...

  14. Power requirements for electron cyclotron current drive and ion cyclotron resonance heating for sawtooth control in ITER

    CERN Document Server

    Chapman, I T; Sauter, O; Zucca, C; Asunta, O; Buttery, R J; Coda, S; Goodman, T; Igochine, V; Johnson, T; Jucker, M; La Haye, R J; Lennholm, M; Contributors, JET-EFDA

    2013-01-01

    13MW of electron cyclotron current drive (ECCD) power deposited inside the q = 1 surface is likely to reduce the sawtooth period in ITER baseline scenario below the level empirically predicted to trigger neo-classical tearing modes (NTMs). However, since the ECCD control scheme is solely predicated upon changing the local magnetic shear, it is prudent to plan to use a complementary scheme which directly decreases the potential energy of the kink mode in order to reduce the sawtooth period. In the event that the natural sawtooth period is longer than expected, due to enhanced alpha particle stabilisation for instance, this ancillary sawtooth control can be provided from > 10MW of ion cyclotron resonance heating (ICRH) power with a resonance just inside the q = 1 surface. Both ECCD and ICRH control schemes would benefit greatly from active feedback of the deposition with respect to the rational surface. If the q = 1 surface can be maintained closer to the magnetic axis, the efficacy of ECCD and ICRH schemes sig...

  15. Simulation of injector dynamics during steady inductive helicity injection current drive in the HIT-SI experiment

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, C., E-mail: hansec@uw.edu [PSI-Center, University of Washington, Seattle, Washington 98195 (United States); Columbia University, New York, New York 10027 (United States); Marklin, G. [PSI-Center, University of Washington, Seattle, Washington 98195 (United States); Victor, B. [HIT-SI Group, University of Washington, Seattle, Washington 98195 (United States); Akcay, C. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Jarboe, T. [HIT-SI Group, University of Washington, Seattle, Washington 98195 (United States); PSI-Center, University of Washington, Seattle, Washington 98195 (United States)

    2015-04-15

    We present simulations of inductive helicity injection in the Helicity Injected Torus with Steady Inductive helicity injection (HIT-SI) device that treats the entire plasma volume in a single dynamic MHD model. A new fully 3D numerical tool, the PSI-center TETrahedral mesh code, was developed that provides the geometric flexibility required for this investigation. Implementation of a zero-β Hall MHD model using PSI-TET will be presented including formulation of a new self-consistent magnetic boundary condition for the wall of the HIT-SI device. Results from simulations of HIT-SI are presented focusing on injector dynamics that are investigated numerically for the first time. Asymmetries in the plasma loading between the two helicity injectors and progression of field reversal in each injector are observed. Analysis indicates cross-coupling between injectors through confinement volume structures. Injector impedance is found to scale with toroidal current at fixed density, consistent with experimental observation. Comparison to experimental data with an injector drive frequency of 14.5 kHz shows good agreement with magnetic diagnostics. Global mode structures from Bi-Orthogonal decomposition agree well with experimental data for the first four modes.

  16. STARLITE figures of merit for tokamak current drive -- Economic analysis of pulsed and steady state power plants with various engineering and physics performance parameters

    Energy Technology Data Exchange (ETDEWEB)

    Ehst, D.A. [Argonne National Lab., IL (United States); Jardin, S.; Kessel, C. [Princeton Univ., NJ (United States). Plasma Physics Lab.

    1995-10-01

    The physics efficiency of current drive ({gamma}{sub B} {proportional_to} n{sub e} I{sub 0} R{sub 0}/P{sub CD}), including the bootstrap effect, needs to exceed certain goals in order to provide economical steady state operation compared to pulsed power plants. The goal for {gamma}{sub B} depends not only on engineering performance of the current drive system, but also on normalized beta and the effective safety factor of the achievable MHD equilibrium.

  17. Starlite figures of merit for tokamak current drive - economic analysis of pulsed and steady state power plants with various engineering and physics performance parameters

    Energy Technology Data Exchange (ETDEWEB)

    Ehst, D.A.

    1995-09-01

    The physics efficiency of current drive ({gamma}{sub B} {proportional_to} n{sub e} I{sub o} R{sub o}/P{sub CD}), including the bootstrap effect, needs to exceed certain goals in order to provide economical steady state operation compared to pulsed power plants. The goal for {gamma}{sub B} depends not only on engineering performance of the current drive system, but also on normalized beta and the effective safety factor of the achievable MHD equilibrium.

  18. Coordination between Fault-Ride-Through Capability and Over-current Protection of DFIG Generators for Wind Farms

    DEFF Research Database (Denmark)

    Bak-Jensen, Birgitte; Kawady, T.A.; Abdel-Rahman, Mansour Hassan

    2010-01-01

    is investigated. Simulation test cases using MATLAB-Simulink are implemented on a 365-MW wind farm in AL-Zaafarana, Egypt. The simulation results show the influence of the FRT capability on the protective relaying coordination in wind farms, showing that the FRT may work in situations where is were expected...

  19. Fault Ride Though Control of Photovoltaic Grid-connected Inverter with Current-limited Capability under Offshore Unbalanced Voltage Conditions

    DEFF Research Database (Denmark)

    Liu, Wenzhao; Guo, Xiaoqiang; Savaghebi, Mehdi;

    2016-01-01

    of the excessive current phenomenon with the conventional fault ride through control is discussed. The quantitative analysis of the current peak value is conducted and a new current-limiting control strategy is proposed to achieve the flexible power control and successful fault ride through in a safe current......The photovoltaic (PV) inverter installed on board experiences the excessive current stress in case of the offshore unbalanced voltage fault ride through (FRT), which significantly affects the operation reliability of the power supply system. In order to solve the problem, the inherent mechanism...

  20. Transformer-based asymmetrical embedded Z-source neutral point clamped inverters with continuous input current and enhanced voltage boost capability

    DEFF Research Database (Denmark)

    Mo, W.; Loh, Poh Chiang; Blaabjerg, Frede

    2013-01-01

    Z-source Neutral Point Clamped (NPC) inverters were introduced to integrate both the advantages of Z-source inverters and NPC inverters. However, traditional Z-source inverters suffer from high voltage stress and chopping input current. This paper proposes six types transformer-based impedance-source...... NPC inverters which have enhanced voltage boost capability and continuous input current by utilizing of transformer and embedded dc source configuration. Experimental results are presented to verify the theory validation....

  1. Modulation method for a multiple drive system based on a two-stage direct power conversion topology with reduced input current ripple

    DEFF Research Database (Denmark)

    Klumpner, Christian; Blaabjerg, Frede

    2005-01-01

    A new two-stage multi-drive direct power conversion (DPC) topology suited for multi-drive application is proposed, having an input port for a three-phase power supply and several output ports to connect three-phase loads, which are independently controlled and allow for sine wave in-sine wave out...... patterns of the inversion stages, which have to form two groups, allowing for size reduction of the input current filter. This is validated by experiments on a realistic laboratory prototype, while its limitations are determined by simulations....

  2. Surge current capabilities and isothermal current-voltage characteristics of high-voltage 4H-SiC junction barrier Schottky rectifiers

    Science.gov (United States)

    Palmour, J. W.; Levinshtein, M. E.; Ivanov, P. A.; Zhang, Q. J.

    2015-06-01

    Isothermal forward current-voltage characteristics of high-voltage 4H-SiC junction barrier Schottky rectifiers (JBS) have been studied for the first time. Isothermal characteristics were measured with JBS having a blocking voltage of 1700 V up to a current density j  ≈  4200 A cm-2 in the temperature range 297-460 K. Quasi-isothermal current-voltage characteristics of these devices were studied with injection of minority carriers (holes) up to j  ≈  7200 A cm-2 and ambient temperatures of 297 and 460 K. The isothermal forward current-voltage characteristics make it possible to numerically calculate (for example, by an iteration procedure) the overheating in an arbitrary operation mode.

  3. Eddy-current analysis of isolated permanent-magnet drives using two- and three-dimensional finite-element methods (abstract)

    Science.gov (United States)

    Ferreira, C. A.

    1990-05-01

    Present drive systems which rely on mechanical devices for torque transmission have some negative features: the driven component cannot be isolated from the drive motor, rotating seals have inherent leakage and friction problems, and mechanical failures often occur due to torque overloads. Magnetic couplings are especially well suited for use in isolated-drive systems. This is often the case in military and aerospace applications where pumps and compressors are vital parts of the thermal and fuel operating systems. The application of permanent-magnet couplings in isolated drives requires accurate calculation of the eddy-current losses induced on the hermetic vessel. This is because the losses along with the required output torque dictate the size and efficiency of the permanent-magnet coupling. The vessel isolates the drive member from the driven member of the turbocompressor. The paper will show the formulation of the computational method based on the Poynting-vector theorem and the concept of motional electric field intensity. The eddy-current losses are calculated using two- and three-dimensional magnetostatic finite-element (FE) analysis. A comparison of the results obtained by two- and three-dimensional FE analysis is made. The results of the analysis will be compared to test data for verification. The test-facility setup and procedure will also be described. This state-of-the-art technique for computation of eddy-current losses has several advantages over conventional analysis methods: the nonlinearities of the magnetic circuit are taken into account, magnetic field fringing and end-leakage effects are not neglected, and the method does not rely on the use of empirical factors. The significant benefits of this approach are that trial-and-error experimental design approaches are eliminated and test data provide validation of analytical results.

  4. HARMONIC DRIVE SELECTION

    Directory of Open Access Journals (Sweden)

    Piotr FOLĘGA

    2014-03-01

    Full Text Available The variety of types and sizes currently in production harmonic drive is a problem in their rational choice. Properly selected harmonic drive must meet certain requirements during operation, and achieve the anticipated service life. The paper discusses the problems associated with the selection of the harmonic drive. It also presents the algorithm correct choice of harmonic drive. The main objective of this study was to develop a computer program that allows the correct choice of harmonic drive by developed algorithm.

  5. Aircraft modifications: Assessing the current state of Air Force aircraft modifications and the implications for future military capability

    Science.gov (United States)

    Hill, Owen Jacob

    How prepared is the U.S. Air Force to modify its aircraft fleet in upcoming years? Aircraft modernization is a complex interaction of new and legacy aircraft, organizational structure, and planning policy. This research will take one component of modernization: aircraft modification, and apply a new method of analysis in order to help formulate policy to promote modernization. Departing from previous small-sample studies dependent upon weight as a chief explanatory variable, this dissertation incorporates a comprehensive dataset that was constructed for this research of all aircraft modifications from 1996 through 2005. With over 700 modification programs, this dataset is used to examine changes to the current modification policy using policy-response regression models. These changes include separating a codependent procurement and installation schedule, reducing the documentation requirements for safety modifications, and budgeting for aging aircraft modifications. The research then concludes with predictive models for the F-15 and F-16 along with their replacements: the F-22 and F-35 Joint Strike Fighter.

  6. The LLNL High Accuracy Volume Renderer for Unstructured Data: Capabilities, Current Limits, and Potential for ASCI/VIEWS Deployment

    Energy Technology Data Exchange (ETDEWEB)

    Williams, P L; Max, N L

    2001-06-04

    This report describes a volume rendering system for unstructured data, especially finite element data, that creates images with very high accuracy. The system will currently handle meshes whose cells are either linear or quadratic tetrahedra, or meshes with mixed cell types: tetrahedra, bricks, prisms, and pyramids. The cells may have nonplanar facets. Whenever possible, exact mathematical solutions for the radiance integrals and for interpolation are used. Accurate semitransparent shaded isosurfaces may be embedded in the volume rendering. For very small cells, subpixel accumulation by splatting is used to avoid sampling error. A new exact and efficient visibility ordering algorithm is described. The most accurate images are generated in software, however, more efficient algorithms utilizing graphics hardware may also be selected. The report describes the parallelization of the system for a distributed-shared memory multiprocessor machine, and concludes by discussing the system's limits, desirable future work, and ways to extend the system so as to be compatible with projected ASCI/VIEWS architectures.

  7. Application of very high harmonic fast waves for off-axis current drive in the DIII-D and FNSF-AT tokamaks

    Science.gov (United States)

    Prater, R.; Moeller, C. P.; Pinsker, R. I.; Porkolab, M.; Meneghini, O.; Vdovin, V. L.

    2014-08-01

    Fast waves at frequencies far above the ion cyclotron frequency and approaching the lower hybrid frequency (also called 'helicons' or ‘whistlers’) have application to off-axis current drive in tokamaks with high electron beta. The high frequency causes the whistler-like behaviour of the wave power nearly following field lines, but with a small radial component, so the waves spiral slowly towards the plasma centre. The high frequency also contributes to strong damping. Modelling predicts robust off-axis current drive with good efficiency compared to alternatives in high performance discharges in DIII-D and Fusion Nuclear Science Facility (FNSF) when the electron beta is above about 1.8%. Detailed analysis of ray behaviour shows that ray trajectories and damping are deterministic (that is, not strongly affected by plasma profiles or initial ray conditions), unlike the chaotic ray behaviour in lower frequency fast wave experiments. Current drive was found to not be sensitive to the launched value of the parallel index of refraction n‖, so wave accessibility issues can be reduced. Use of a travelling wave antenna provides a very narrow n‖spectrum, which also helps avoid accessibility problems.

  8. The direct relationship between output power and current carrying capability of rotor bars in HTS induction/synchronous motor with the use of DI-BSCCO tapes

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, T; Nagao, K; Nishimura, T; Ogama, Y; Kawamoto, M [Department of Electrical Engineering, Graduate School of Engineering, Kyoto University, 1 Kyoto-Daigaku Katsura, Nishikyo-Ku, Kyoto 615-8510 (Japan); Okazaki, T; Ayai, N; Oyama, H [Electric Power and Energy Research Laboratories, Sumitomo Electric Industries, Ltd, 1-1-3, Shimaya, Konohaya-Ku, Osaka 554-0024 (Japan)], E-mail: tk_naka@kuee.kyoto-u.ac.jp

    2008-08-15

    We report on the direct relationship between output power and the current carrying capability of a squirrel-cage HTS induction/synchronous motor based on experiment. The secondary windings are fabricated by use of so-called DI-BSCCO tapes, and the conventional (normal conducting) stator, three-phase and four-pole, is utilized. The tests are carried out in liquid nitrogen for two kinds of HTS windings, in which the number of HTS rotor bars is varied. It is directly shown that the output power is proportional to the rotor bars' critical current at 77 K. In other words, the torque can be enlarged by increasing the critical current of the HTS rotor bars.

  9. Assessing the test–retest reliability of career path appreciation as a measure of current and potential work decision-making capability

    Directory of Open Access Journals (Sweden)

    Rudolf M. Oosthuizen

    2014-06-01

    Full Text Available Orientation: Assessing and developing managerial decision-making capability in a complex and volatile marketplace is imperative for most South African businesses.Purpose: The objective of this study was to assess the test–retest reliability of the career path appreciation (CPA procedure in assessing current and potential levels of work decision-making capability. The study also explored whether different gender and race groups differed significantly in terms of these levels at two CPA assessments.Motivation for the study: Limited recent test–retest research has been done regarding the reliability of the CPA technique as a tool for measuring the work decision-making capability of professional and managerial talent in the South African context. Scholars and practitioners in the field of industrial psychology could therefore benefit from follow-up research into the reliability of CPA.Research approach, design and method: The research followed an ex post facto correlational design using longitudinal data of a non-probability purposive sample (N = 527 within the Bioss SA database.Main findings: The results showed that the participants’ first CPA assessment scores correlated significantly and positively with their second CPA assessment scores. Gender and race groups differed significantly in their levels of current work decision-making capability at both assessments.Practical/managerial implications: The CPA procedure can be used with confidence as an assessment tool in the selection, mentoring and development of high-potential managerial and professional talent for diverse gender and race groups.Contribution/value-add: These findings contribute valuable information regarding the reliability of CPA and the differences between race and gender groups in the South African context.

  10. Fundamental analysis and development of the current and voltage control method by changing the driving frequency for the transcutaneous energy transmission system.

    Science.gov (United States)

    Miura, Hidekazu; Yamada, Akihiro; Shiraishi, Yasuyuki; Yambe, Tomoyuki

    2015-08-01

    We have been developing transcutaneous energy transmission system (TETS) for a ventricular assist device, shape memory alloy (SMA) fibered artificial organs and so on, the system has high efficiency and a compact size. In this paper, we summarize the development, design method and characteristics of the TETS. New control methods for stabilizing output voltage or current of the TETS are proposed. These methods are primary side, are outside of the body, not depending on a communication system from the inside the body. Basically, the TETS operates at the fixed frequency with a suitable compensation capacitor so that the internal impedance is minimalized and a flat load characteristic is obtained. However, when the coil shifted from the optimal position, the coupling factor changes and the output is fluctuated. TETS has a resonant property; its output can be controlled by changing the driving frequency. The continuous current to continuous voltage driving method was implemented by changing driving frequency and setting of limitation of low side frequency. This method is useful for battery charging system for electrically driven artificial hearts and also useful for SMA fibered artificial organs which need intermittent high peak power comsumption. In this system, the internal storage capacitor is charged slowly while the fibers are turned off and discharge the energy when the fibers are turned on. We examined the effect of the system. It was found that the size and maximum output of the TETS would able to be reduced.

  11. A veterinary and behavioral analysis of dolphin killing methods currently used in the "drive hunt" in Taiji, Japan.

    Science.gov (United States)

    Butterworth, Andrew; Brakes, Philippa; Vail, Courtney S; Reiss, Diana

    2013-01-01

    Annually in Japanese waters, small cetaceans are killed in "drive hunts" with quotas set by the government of Japan. The Taiji Fishing Cooperative in Japan has published the details of a new killing method that involves cutting (transecting) the spinal cord and purports to reduce time to death. The method involves the repeated insertion of a metal rod followed by the plugging of the wound to prevent blood loss into the water. To date, a paucity of data exists regarding these methods utilized in the drive hunts. Our veterinary and behavioral analysis of video documentation of this method indicates that it does not immediately lead to death and that the time to death data provided in the description of the method, based on termination of breathing and movement, is not supported by the available video data. The method employed causes damage to the vertebral blood vessels and the vascular rete from insertion of the rod that will lead to significant hemorrhage, but this alone would not produce a rapid death in a large mammal of this type. The method induces paraplegia (paralysis of the body) and death through trauma and gradual blood loss. This killing method does not conform to the recognized requirement for "immediate insensibility" and would not be tolerated or permitted in any regulated slaughterhouse process in the developed world.

  12. Current Capabilities at SNL for the Integration of Small Modular Reactors onto Smart Microgrids Using Sandia's Smart Microgrid Technology High Performance Computing and Advanced Manufacturing.

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez, Salvador B. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-05-01

    Smart grids are a crucial component for enabling the nation’s future energy needs, as part of a modernization effort led by the Department of Energy. Smart grids and smart microgrids are being considered in niche applications, and as part of a comprehensive energy strategy to help manage the nation’s growing energy demands, for critical infrastructures, military installations, small rural communities, and large populations with limited water supplies. As part of a far-reaching strategic initiative, Sandia National Laboratories (SNL) presents herein a unique, three-pronged approach to integrate small modular reactors (SMRs) into microgrids, with the goal of providing economically-competitive, reliable, and secure energy to meet the nation’s needs. SNL’s triad methodology involves an innovative blend of smart microgrid technology, high performance computing (HPC), and advanced manufacturing (AM). In this report, Sandia’s current capabilities in those areas are summarized, as well as paths forward that will enable DOE to achieve its energy goals. In the area of smart grid/microgrid technology, Sandia’s current computational capabilities can model the entire grid, including temporal aspects and cyber security issues. Our tools include system development, integration, testing and evaluation, monitoring, and sustainment.

  13. Influence of impurity and recycling on high-β steady-state plasmas sustained by rotating magnetic fields current drive

    Science.gov (United States)

    Guo, H. Y.; Grossnickle, J. A.; Hoffman, A. L.; Vlases, G. C.

    2009-06-01

    A new upgrade of the Translation, Confinement, and Sustainment (TCS) device, TCSU, has been built to form and sustain high temperature compact toroids (CT), known as Field Reversed Configurations, using Rotating Magnetic Fields (RMF). In TCS the plasma temperature was limited to several 10s of eV due to high impurity content. These impurities are greatly reduced in TCSU by using advanced plasma chamber and helium glow discharge cleaning. Reducing impurity radiation, when coupled with reduced overall recycling, enabled the plasma to enter into a new, collisionless regime with temperatures well over 200 eV, substantially exceeding the radiation barrier. This is a first for CTs at low input power density. This was achieved using the simple even-parity RMF drive (despite transient opening of field lines by the RMF) because the associated energy loss is sheath-limited, coupled with the low edge density resulting from the RMF pinch effect.

  14. Design and fabrication of nano-ring MRAM demo devices based on spin-polarized current driving

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Nano-ring-type magnetic tunnel junctions(NR-MTJ)were nano-fabricated.The tunneling magnetoresistance(TMR)versus current(Ⅰ)loops of the NR-MTJs for a spin-polarized current switching were measured and the TMR ratio of around 20%~50% with a Al-O barrier at room temperature were observed.The critical value of switching current for the free Co_(60)Fe_(20)B_(20) layer between parallel and anti-parallel magnetization states is smaller than 650μA.The NR-MTJs arrays were also integrated above the transistors in ...

  15. The impact of interface states on the mobility and drive current of In0.53Ga0.47 As semiconductor n-MOSFETs

    Science.gov (United States)

    Osgnach, Patrik; Caruso, Enrico; Lizzit, Daniel; Palestri, Pierpaolo; Esseni, David; Selmi, Luca

    2015-06-01

    Accurate Schrödinger-Poisson and Multi-Subband Monte Carlo simulations are used to investigate the effect of interface states at the channel-insulator interface of In0.53Ga0.47 As MOSFETs. Acceptor states with energy inside the conduction band of the semiconductor can explain the dramatic Fermi level pinning observed in the experiments. Our results show that these states significantly impact the electrical mobility measurements but they appear to have a limited influence on the static current drive of short channel devices.

  16. Observation of Lower Hybrid Current Drive Improved Confinement with a Graphite Probe at the Last Closed Flux Surface of the HT-7 Tokamak

    Institute of Scientific and Technical Information of China (English)

    徐国盛; 万宝年; 宋梅; 凌必利; 匡光力; 丁伯江

    2002-01-01

    High time resolution measurements of the electrostatic fluctuations, radial electric field Er and turbulence-induced electron flux Гe have been performed across the transition of lower hybrid current drive improved confinement with a graphite Langmuir probe array at the last closed flux surface of the HT-7 tokamak. The decrease of Гe is dominated by the suppression of fluctuation levels, which follows the change of Er. A reversal of the poloidal propagation direction of turbulence demonstrates that the poloidal propagation is dominated by Eт× Bφ drift. The enhancement of poloidal coherence accompanies the fluctuation suppression, which suggests the subtle variation of turbulence features.

  17. Capability Paternalism

    NARCIS (Netherlands)

    Claassen, R.J.G.

    2014-01-01

    A capability approach prescribes paternalist government actions to the extent that it requires the promotion of specific functionings, instead of the corresponding capabilities. Capability theorists have argued that their theories do not have much of these paternalist implications, since promoting c

  18. A Study of Energy Conversion Efficiency Versus Plasma Density by Lower Hybrid Current Drive in HT-7 Tokamak

    Institute of Scientific and Technical Information of China (English)

    丁伯江; 匡光力; 刘岳修; 刘登成; 单家方; 刘甫坤; 沈慰慈; 石跃江; 吴振伟; 林建安; 俞家文; 徐汉东; 商连全; 张晓东; 刘小宁; 赵燕平; 李建刚

    2002-01-01

    Ramp-up experiments by means of lower hybrid wave on HT-7 superconducting tokamak have been performed and analyzed. A ramp-up rate of over 300 kA/s is obtained and a conversion efficiency of over 10% has been achieved during the ramp-up phase. The study of the dependence of conversion efficiency on plasma density shows that the conversion efficiency is affected by the driven current, which is mainly dominated by the competition of impurity concentration with wave accessibility condition. In addition, the effect of current profile may play an important role in determining the conversion efficiency.

  19. A Study of Energy Conversion Efficiency Versus Plasma Density by Lower Hybrid Current Drive in HT—7 Tokamak

    Institute of Scientific and Technical Information of China (English)

    丁伯江; 匡光力; 等

    2002-01-01

    Ramp-up experiments by means of lower hydrid wave on HT-7 superconducting tokamak have been performed and analyzed.A ramp-up rate of over 300kA/s is obtained and a conversion efficiency of over 10% has been achieved during the ramp-up phases.The study of the dependence of conversion efficiency on plasma density shows that the conversion efficiency is affected by the driven current,which is mainly dominated by the competition of impurity concentration with wave accessibility condition.In addition,the effect of current profile may play an important role in determining the conversion efficiency.

  20. Analytical Chemistry Core Capability Assessment - Preliminary Report

    Energy Technology Data Exchange (ETDEWEB)

    Barr, Mary E. [Los Alamos National Laboratory; Farish, Thomas J. [Los Alamos National Laboratory

    2012-05-16

    The concept of 'core capability' can be nebulous one. Even at a fairly specific level, where core capability equals maintaining essential services, it is highly dependent upon the perspective of the requestor. Samples are submitted to analytical services because the requesters do not have the capability to conduct adequate analyses themselves. Some requests are for general chemical information in support of R and D, process control, or process improvement. Many analyses, however, are part of a product certification package and must comply with higher-level customer quality assurance requirements. So which services are essential to that customer - just those for product certification? Does the customer also (indirectly) need services that support process control and improvement? And what is the timeframe? Capability is often expressed in terms of the currently utilized procedures, and most programmatic customers can only plan a few years out, at best. But should core capability consider the long term where new technologies, aging facilities, and personnel replacements must be considered? These questions, and a multitude of others, explain why attempts to gain long-term consensus on the definition of core capability have consistently failed. This preliminary report will not try to define core capability for any specific program or set of programs. Instead, it will try to address the underlying concerns that drive the desire to determine core capability. Essentially, programmatic customers want to be able to call upon analytical chemistry services to provide all the assays they need, and they don't want to pay for analytical chemistry services they don't currently use (or use infrequently). This report will focus on explaining how the current analytical capabilities and methods evolved to serve a variety of needs with a focus on why some analytes have multiple analytical techniques, and what determines the infrastructure for these analyses. This

  1. Five-Phase Five-Level Open-Winding/Star-Winding Inverter Drive for Low-Voltage/High-Current Applications

    DEFF Research Database (Denmark)

    Padmanaban, Sanjeevi Kumar; Blaabjerg, Frede; Wheeler, Patrick

    2016-01-01

    This paper work proposed a five-phase five-level open-/star-winding multilevel AC converter suitable for low-voltage/high-current applications. Modular converter consists of classical two-level five-phase voltage source inverter (VSI) with slight reconfiguration to serve as a multilevel converter...

  2. Drive Stands

    Data.gov (United States)

    Federal Laboratory Consortium — The Electrical Systems Laboratory (ESL)houses numerous electrically driven drive stands. A drive stand consists of an electric motor driving a gearbox and a mounting...

  3. Numerical Simulations of Electrokinetic Processes Comparing the Use of a Constant Voltage Difference or a Constant Current as Driving Force

    DEFF Research Database (Denmark)

    Paz-Garcia, Juan Manuel; Johannesson, Björn; Ottosen, Lisbeth M.

    materials and the prevention of the reinforced concrete corrosion. The electrical energy applied in an electrokinetic process produces electrochemical reactions at the electrodes. Different electrode processes can occur. When considering inert electrodes in aqueous solutions, the reduction of water...... are transported from the anode to the cathode through the closed electrical circuit of the cell. In the solution, the electrical current is carried by the ions, which move towards the electrode with different charge. Therefore, different authors have studied the system using the circuit theory. Assuming...

  4. Study of Bridging of the Spectral Gap in the Lower Hybrid Wave Current Drive in the HT-7 Tokamak

    Institute of Scientific and Technical Information of China (English)

    WANG Mao; DING Bojiang; XU Handong; ZHAO Lianmin; LIU Liang; LIN Shiyao; XU Ping; SUN Youwen; HU Huaichuan; YANG Yong; JIA Hua; WANG Xiaojie; WANG Dongxia; QIN Yongliang; FENG Jianqiang; LIU Fukun; SHAN Jiafang; ZHAO Yanping; HT-7 team

    2009-01-01

    An additional lower hybrid wave (LHW) with a higher refractive index(N//)was investigated in the HT-7 tokamak to bridge the spectral gap.It was found that the spectral gap between the wave and the electrons in the outer region was bridged by the additional wave with a higher N// spectrum.The results showed that the sawteeth oscillation was suppressed by launching the additional wave,and that the power deposition profile was moved outwards and the current profile was broadened due to the application of the additional wave.Our study indicates that the spectral gap may be bridged by an additional wave with a higher N// spectrum in the outer region.

  5. Quasi-two-dimensional subthreshold current model of deep submicrometer SOI drive-in gate controlled hybrid transistors with lateral non-uniform doping profile

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    We have analyzed the operating mechanism of the novel deep submicrometer SOI drive-in gate controlled hybrid transistor (DGCHT), which can effectively alleviate the contradiction between speed enhancement and power reduction in conventional MOS devices and can improve the output resistance. On the basis of this, the subthreshold current model of DGCHTs is proposed. The model takes into account the impact of lateral non-uniform doping profile on body effect, short-channel effect and carrier mobility. Considering the mobile charge, two-dimensional Poisson equation is solved with quasi-two-dimensional analysis and parabolic approximation of surface potential. With the surface potential obtained, the subthreshold current is figured out, including both the diffusion and drift component. The calculated results are in good agreement with the MEDICI numerical simulation results, indicating the correct description of the current characteristics of SOI DGCHT by the presented model. The model can also be considered as an important reference to the current simulation of deep submicrometer MOSFET with pocket implantation.

  6. An Insight into the Time Domain Phenomenon during the Transition Zone from Induction Motor to Synchronous Motor Mode for a Current Source Inverter Fed Synchronous Motor Drive System

    Directory of Open Access Journals (Sweden)

    A.B. Chattopadhyay

    2014-10-01

    Full Text Available Modeling of synchronous motor plays a dominant role in designing complicated drive system for different applications, especially large blower fans etc., for steel industries. As synchronous motor has no inherent starting torque generally it is started as an induction motor with the help of a damper winding and it pulls into synchronism under certain conditions. The present study exactly concentrates on this particular zone of transition from induction motor to synchronous motor mode for a current source inverter fed synchronous motor drive system. Due to complexity of synchronous motor in terms of number of windings and finite amount of air gap saliency, direct modeling of such transition zone in time domain becomes cumbersome at the first instance of modeling. That is why firstly the modeling is presented in complex frequency domain and then the time domain modeling is obtained by applying inverse Laplace transform technique. Apparently it seems to be a straight forward mathematical treatment but involvement of Convolution Integral for converting the formulation from s-domain to time domain becomes a matter of interest and it may draw the attention of various researchers working in this area. Furthermore the time domain response of the disturbance function may help a designer to fix up the time instant when the pull in phenomenon will be imposed by throwing the field winding to a DC supply.

  7. Capability ethics

    NARCIS (Netherlands)

    I.A.M. Robeyns (Ingrid)

    2012-01-01

    textabstractThe capability approach is one of the most recent additions to the landscape of normative theories in ethics and political philosophy. Yet in its present stage of development, the capability approach is not a full-blown normative theory, in contrast to utilitarianism, deontological

  8. Capability ethics

    NARCIS (Netherlands)

    I.A.M. Robeyns (Ingrid)

    2012-01-01

    textabstractThe capability approach is one of the most recent additions to the landscape of normative theories in ethics and political philosophy. Yet in its present stage of development, the capability approach is not a full-blown normative theory, in contrast to utilitarianism, deontological theor

  9. Capability ethics

    NARCIS (Netherlands)

    I.A.M. Robeyns (Ingrid)

    2012-01-01

    textabstractThe capability approach is one of the most recent additions to the landscape of normative theories in ethics and political philosophy. Yet in its present stage of development, the capability approach is not a full-blown normative theory, in contrast to utilitarianism, deontological theor

  10. Mesoscale SST-wind stress coupling in the Peru-Chile current system: Which mechanisms drive its seasonal variability?

    Science.gov (United States)

    Oerder, Vera; Colas, François; Echevin, Vincent; Masson, Sebastien; Hourdin, Christophe; Jullien, Swen; Madec, Gurvan; Lemarié, Florian

    2016-10-01

    Satellite observations and a high-resolution regional ocean-atmosphere coupled model are used to study the air/sea interactions at the oceanic mesoscale in the Peru-Chile upwelling current system. Coupling between mesoscale sea surface temperature (SST) and wind stress (WS) intensity is evidenced and characterized by correlations and regression coefficients. Both the model and the observations display similar spatial and seasonal variability of the coupling characteristics that are stronger off Peru than off Northern Chile, in relation with stronger wind mean speed and steadiness. The coupling is also more intense during winter than during summer in both regions. It is shown that WS intensity anomalies due to SST anomalies are mainly forced by mixing coefficient anomalies and partially compensated by wind shear anomalies. A momentum balance analysis shows that wind speed anomalies are created by stress shear anomalies. Near-surface pressure gradient anomalies have a negligible contribution because of the back-pressure effect related to the air temperature inversion. As mixing coefficients are mainly unchanged between summer and winter, the stronger coupling in winter is due to the enhanced large-scale wind shear that enables a more efficient action of the turbulent stress perturbations. This mechanism is robust as it does not depend on the choice of planetary boundary layer parameterization.

  11. Current selection for lower migratory activity will drive the evolution of residency in a migratory bird population.

    Science.gov (United States)

    Pulido, Francisco; Berthold, Peter

    2010-04-20

    Global warming is impacting biodiversity by altering the distribution, abundance, and phenology of a wide range of animal and plant species. One of the best documented responses to recent climate change is alterations in the migratory behavior of birds, but the mechanisms underlying these phenotypic adjustments are largely unknown. This knowledge is still crucial to predict whether populations of migratory birds will adapt to a rapid increase in temperature. We monitored migratory behavior in a population of blackcaps (Sylvia atricapilla) to test for evolutionary responses to recent climate change. Using a common garden experiment in time and captive breeding we demonstrated a genetic reduction in migratory activity and evolutionary change in phenotypic plasticity of migration onset. An artificial selection experiment further revealed that residency will rapidly evolve in completely migratory bird populations if selection for shorter migration distance persists. Our findings suggest that current alterations of the environment are favoring birds wintering closer to the breeding grounds and that populations of migratory birds have strongly responded to these changes in selection. The reduction of migratory activity is probably an important evolutionary process in the adaptation of migratory birds to climate change, because it reduces migration costs and facilitates the rapid adjustment to the shifts in the timing of food availability during reproduction.

  12. Dynamic capabilities

    DEFF Research Database (Denmark)

    Grünbaum, Niels Nolsøe; Stenger, Marianne

    2013-01-01

    it was dominated by a lack of systematism, assessment, monitoring, marketing speculations and feasibility calculation. Furthermore, the sphere was dictated by asymmetric supplier-customer relationships and negotiation power leading, among other possible factors, to meager profitability.......The consequences of dynamic capabilities (i.e. innovation performance and profitability) is an under researched area in the growing body of literature on dynamic capabilities and innovation management. This study aims to examine the relationship between dynamic capabilities, innovation performance...... and profitability of small and medium sized manufacturing enterprises operating in volatile environments. A multi-case study design was adopted as research strategy. The findings reveal a positive relationship between dynamic capabilities and innovation performance in the case companies, as we would expect. It was...

  13. Drugged Driving

    Science.gov (United States)

    ... Parents & Educators Children & Teens Search Connect with NIDA : Google Plus Facebook LinkedIn Twitter YouTube Flickr RSS Menu ... misuse of prescription drugs can make driving a car unsafe—just like driving after drinking alcohol. Drugged ...

  14. Resurgent Na+ current in pyramidal neurones of rat perirhinal cortex: axonal location of channels and contribution to depolarizing drive during repetitive firing

    Science.gov (United States)

    Castelli, Loretta; Biella, Gerardo; Toselli, Mauro; Magistretti, Jacopo

    2007-01-01

    The perirhinal cortex (PRC) is a supra-modal cortical area that collects and integrates information originating from uni- and multi-modal neocortical regions and directed to the hippocampus. The mechanisms that underlie the specific excitable properties of the different PRC neuronal types are still largely unknown, and their elucidation may be important in understanding the integrative functions of PRC. In this study we investigated the expression and properties of resurgent Na+ current (INaR) in pyramidal neurones of rat PRC area 35 (layer II). Patch-clamp experiments in acute PRC slices were first carried out. A measurable INaR was expressed by a large majority of neurones (31 out of 35 cells). INaR appeared as an inward, slowly decaying current elicited upon step repolarization after depolarizations sufficient to induce nearly complete inactivation of the transient Na+ current (INaT). INaR had a peak amplitude of ∼2.5% that of INaT, and showed the typical biophysical properties also observed in other neuronal types (i.e. cerebellar Purkinje and granule cells), including a bell-shaped current–voltage relationship with a peak at approximately −40 mV, and a characteristic acceleration of activation and decay speed at potentials negative to −45 mV. Current-clamp experiments were then carried out in which repetitive action-potential discharge at various frequencies was induced with depolarizing current injection. The voltage signals thus obtained were then used as command waveforms for voltage-clamp recordings. These experiments showed that a Na+ current identifiable as INaR activates in the early interspike phase even at relatively high firing frequencies (20 Hz), thereby contributing to the depolarizing drive and possibly enhancing repetitive discharge. In acutely dissociated area 35 layer II neurones, as well as in nucleated patches from the same neurones, INaR was never observed, despite the presence of typical INaTs. Since in both preparations neuronal

  15. Capability approach

    DEFF Research Database (Denmark)

    Jensen, Niels Rosendal; Kjeldsen, Christian Christrup

    Lærebogen er den første samlede danske præsentation af den af Amartya Sen og Martha Nussbaum udviklede Capability Approach. Bogen indeholder en præsentation og diskussion af Sen og Nussbaums teoretiske platform. I bogen indgår eksempler fra såvel uddannelse/uddannelsespolitik, pædagogik og omsorg....

  16. ENTREPRENEURIAL CAPABILITIES

    DEFF Research Database (Denmark)

    Rasmussen, Lauge Baungaard; Nielsen, Thorkild

    2003-01-01

    The aim of this article is to analyse entrepreneurship from an action research perspective. What is entrepreneurship about? Which are the fundamental capabilities and processes of entrepreneurship? To answer these questions the article includes a case study of a Danish entrepreneur and his networks...

  17. Driving Behaviour Profile of Drivers with Autism Spectrum Disorder (ASD).

    Science.gov (United States)

    Chee, Derserri Y; Lee, Hoe C; Patomella, Ann-Helen; Falkmer, Torbjörn

    2017-06-05

    The symptomatology of autism spectrum disorder (ASD) can make driving risky, but little is known about the on-road driving behaviour of individuals with ASD. This study assessed and compared the on-road driving performance of drivers with and without ASD, and explored how the symptomatology of ASD hinders or facilitates on-road driving performance. Sixteen drivers with ASD and 21 typically-developed drivers participated in the study. Drivers with ASD underperformed in vehicle manoeuvring, especially at left-turns, right-turns and pedestrian crossings. However, drivers with ASD outperformed the TD group in aspects related to rule-following such as using the indicator at roundabouts and checking for cross-traffic when approaching intersections. Drivers with ASD in the current study presented with a range of capabilities and weaknesses during driving.

  18. Toward a Public Toxicogenomics Capability for Supporting Predictive Toxicology: Survey of Current Resources and Chemical Indexing of Experiments in GEO and ArrayExpress

    Science.gov (United States)

    A publicly available toxicogenomics capability for supporting predictive toxicology and meta-analysis depends on availability of gene expression data for chemical treatment scenarios, the ability to locate and aggregate such information by chemical, and broad data coverage within...

  19. Electric drives

    CERN Document Server

    Boldea, Ion

    2005-01-01

    ENERGY CONVERSION IN ELECTRIC DRIVESElectric Drives: A DefinitionApplication Range of Electric DrivesEnergy Savings Pay Off RapidlyGlobal Energy Savings Through PEC DrivesMotor/Mechanical Load MatchMotion/Time Profile MatchLoad Dynamics and StabilityMultiquadrant OperationPerformance IndexesProblemsELECTRIC MOTORS FOR DRIVESElectric Drives: A Typical ConfigurationElectric Motors for DrivesDC Brush MotorsConventional AC MotorsPower Electronic Converter Dependent MotorsEnergy Conversion in Electric Motors/GeneratorsPOWER ELECTRONIC CONVERTERS (PECs) FOR DRIVESPower Electronic Switches (PESs)The

  20. Dynamic capabilities

    DEFF Research Database (Denmark)

    Grünbaum, Niels Nolsøe; Stenger, Marianne

    2013-01-01

    and profitability of small and medium sized manufacturing enterprises operating in volatile environments. A multi-case study design was adopted as research strategy. The findings reveal a positive relationship between dynamic capabilities and innovation performance in the case companies, as we would expect. It was...... it was dominated by a lack of systematism, assessment, monitoring, marketing speculations and feasibility calculation. Furthermore, the sphere was dictated by asymmetric supplier-customer relationships and negotiation power leading, among other possible factors, to meager profitability....

  1. It does not always have to be three-phase current. Digitalisation makes dc drives still attractive. Es muss nicht immer Drehstrom sein. Digitalisierung macht Gleichstromantriebe weiter attraktiv

    Energy Technology Data Exchange (ETDEWEB)

    Heinrich, W. (ABB Antriebstechnik GmbH, Lampertheim (Germany))

    1992-01-31

    The stormy development of three-phase drives has replaced the dc systems in mechanical engineering and plant engineering partially, but the dc drive has managed to preserve its attractivity. Digitalisation sees to it. The progress made here is proved by the example a digital compact power converter of the second generation. (orig.).

  2. Subsurface flow and transport of organic chemicals: an assessment of current modeling capability and priority directions for future research (1987-1995)

    Energy Technology Data Exchange (ETDEWEB)

    Streile, G.P.; Simmons, C.S.

    1986-09-01

    Theoretical and computer modeling capability for assessing the subsurface movement and fate of organic contaminants in groundwater was examined. Hence, this study is particularly concerned with energy-related, organic compounds that could enter a subsurface environment and move as components of a liquid phase separate from groundwater. The migration of organic chemicals that exist in an aqueous dissolved state is certainly a part of this more general scenario. However, modeling of the transport of chemicals in aqueous solution has already been the subject of several reviews. Hence, this study emphasizes the multiphase scenario. This study was initiated to focus on the important physicochemical processes that control the behavior of organic substances in groundwater systems, to evaluate the theory describing these processes, and to search for and evaluate computer codes that implement models that correctly conceptualize the problem situation. This study is not a code inventory, and no effort was made to identify every available code capable of representing a particular process.

  3. Distracted Driving

    Science.gov (United States)

    ... What's this? Submit What's this? Submit Button Distracted Driving Recommend on Facebook Tweet Share Compartir Each day in the United States, over 8 people are killed and 1,161 injured in crashes ...

  4. DRIVING GREEN

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    China is promoting environmentally friendly cars to save energy and protect the environment While people enjoy the pleasure and convenience of driving, they are also creating and breathing more and more toxic

  5. Characterization of Electrical Current-Generation Capabilities from Thermophilic Bacterium Thermoanaerobacter pseudethanolicus Using Xylose, Glucose, Cellobiose, or Acetate with Fixed Anode Potentials.

    Science.gov (United States)

    Lusk, Bradley G; Khan, Qaiser Farid; Parameswaran, Prathap; Hameed, Abdul; Ali, Naeem; Rittmann, Bruce E; Torres, Cesar I

    2015-12-15

    Thermoanaerobacter pseudethanolicus 39E (ATCC 33223), a thermophilic, Fe(III)-reducing, and fermentative bacterium, was evaluated for its ability to produce current from four electron donors-xylose, glucose, cellobiose, and acetate-with a fixed anode potential (+ 0.042 V vs SHE) in a microbial electrochemical cell (MXC). Under thermophilic conditions (60 °C), T. pseudethanolicus produced high current densities from xylose (5.8 ± 2.4 A m(-2)), glucose (4.3 ± 1.9 A m(-2)), and cellobiose (5.2 ± 1.6 A m(-2)). It produced insignificant current when grown with acetate, but consumed the acetate produced from sugar fermentation to produce electrical current. Low-scan cyclic voltammetry (LSCV) revealed a sigmoidal response with a midpoint potential of -0.17 V vs SHE. Coulombic efficiency (CE) varied by electron donor, with xylose at 34.8% ± 0.7%, glucose at 65.3% ± 1.0%, and cellobiose at 27.7% ± 1.5%. Anode respiration was sustained over a pH range of 5.4-8.3, with higher current densities observed at higher pH values. Scanning electron microscopy showed a well-developed biofilm of T. pseudethanolicus on the anode, and confocal laser scanning microscopy demonstrated a maximum biofilm thickness (Lf) greater than ~150 μm for the glucose-fed biofilm.

  6. Static load testing of a heliostat drive

    Energy Technology Data Exchange (ETDEWEB)

    Grossman, J.W.

    1991-10-01

    The drive designed and built by the Solar Power Engineering Company (SPECO) for its large area heliostat failed under high wind loads during a winter storm. This report details the testing and analysis done to verify the load capabilities of the rebuilt heliostat drive. Changes in design and improvements in fabrication resulted in a usable drive. 12 figs., 7 tabs.

  7. An Insight into the Time Domain Phenomenon during the Transition Zone from Induction Motor to Synchronous Motor Mode for a Current Source Inverter Fed Synchronous Motor Drive System

    OpenAIRE

    A.B. Chattopadhyay; Sunil Thomas

    2014-01-01

    Modeling of synchronous motor plays a dominant role in designing complicated drive system for different applications, especially large blower fans etc., for steel industries. As synchronous motor has no inherent starting torque generally it is started as an induction motor with the help of a damper winding and it pulls into synchronism under certain conditions. The present study exactly concentrates on this particular zone of transition from induction motor to synchronous motor mode for a cur...

  8. 一个新的适用于无刷直流电机驱动的单电流传感器技术%A Novel Current Sensor Technique for Brushless DC Motor Drives

    Institute of Scientific and Technical Information of China (English)

    谭徽; 江建中; 汪信尧; 王勇

    2000-01-01

    The torque output in a permanent magnet brushless DC motor (BLDCM) is usually controlled by regulating the motor phase currents. In this paper, three kinds of PWM strategies together with some critical review on traditional current measurements in a BLDCM drive system are discussed. A novel method for assessing the PWM information and measuring the motor phase currents by a dc link current sensor is proposed. An attractive feature of the proposed method is the simplicity with the current sample processing because there is no need to incorporate the conduction information of the power switches or diodes. Only the single sided PWM or the double sided complementary PWM is needed with the proposed technique.

  9. Current and Projected Capabilities of the Solar Tower Atmospheric Cherenkov Effect Experiment (STACEE) for gamma -ray Astronomy below 100 GeV

    Science.gov (United States)

    Chantell, M. C.; Covault, C. E.; Dragovan, M.; Ong, R. A.; Oser, S.; Bhattacharya, D.; Tumer, O. T.; Gregorich, D. T.; Hanna, D. S.; Williams, D. A.

    1997-05-01

    There are currently no experiments, either satellite or ground-based, that are sensitive to astrophysical gamma -rays in the energy range between 20 and 250 GeV. We are developing the Solar Tower Atmospheric Cherenkov Effect Experiment (STACEE) to explore this energy range. STACEE will use heliostat mirrors at the National Solar Thermal Test Facility, located at Sandia National Laboratorys near Albuquerque NM., to collect Cherenkov light produced by extensive air showers initiated by high energy gamma -rays. The STACEE collaboration has recently completed a series of tests at this site that demonstrate the ability of this experiment to operate with a gamma -ray energy threshold well below 100 GeV. We present the results of these tests and use them to predict the scientific potential of a 32 heliostat experiment operating for a full winter-spring observing season.

  10. A preliminary study of the statistical analyses and sampling strategies associated with the integration of remote sensing capabilities into the current agricultural crop forecasting system

    Science.gov (United States)

    Sand, F.; Christie, R.

    1975-01-01

    Extending the crop survey application of remote sensing from small experimental regions to state and national levels requires that a sample of agricultural fields be chosen for remote sensing of crop acreage, and that a statistical estimate be formulated with measurable characteristics. The critical requirements for the success of the application are reviewed in this report. The problem of sampling in the presence of cloud cover is discussed. Integration of remotely sensed information about crops into current agricultural crop forecasting systems is treated on the basis of the USDA multiple frame survey concepts, with an assumed addition of a new frame derived from remote sensing. Evolution of a crop forecasting system which utilizes LANDSAT and future remote sensing systems is projected for the 1975-1990 time frame.

  11. Multi-Agent Active Interaction with Driving Assistance Systems

    OpenAIRE

    Barthès, Jean-Paul,; Bonnifait, Philippe

    2010-01-01

    7 pages; International audience; Intelligent vehicles refer currently to vehicles able to drive autonomously or able to provide pertinent information to the driver for safety, assistance and comfort. Cognitive cars are intelligent vehicles with additional capabilities like being able to collaborate with the driver in operating conditions. In this paper, a multi-agent system is used as a “digital butler” that does the interface between the driver and the machine. In order to test this approach...

  12. Death Drive

    OpenAIRE

    Stühler, Rebekka Hellstrøm

    2012-01-01

    The aim of this project is to investigate why the Freudian term Death Drive is not acknowledged in modern psychological therapy. On basis of psychoanalytical theory and through a literary analysis, the project will present a discussion of the significance and presence of the term within these practises.

  13. Effect of transcranial direct current stimulation on visual perception function and performance capability of activities of daily living in stroke patients

    Science.gov (United States)

    Kim, Ko-Un; Kim, Su-Han; An, Tae-Gyu

    2016-01-01

    [Purpose] The purpose of this study was to examine the effects of transcranial direct current stimulation (tDCS) on visual perception and performance of activities of daily living in patients with stroke. [Subjects and Methods] Thirty subjects were assigned equally to a tDCS plus traditional occupational therapy group (experimental group) and a traditional occupational therapy group (control group). The intervention was implemented five times per week, 30 minutes each, for six weeks. In order to assess visual perception function before and after the intervention, the motor-free visual perception test (MVPT) was conducted, and in order to compare the performance of activities of daily living, the Functional Independence Measure scale was employed. [Results] According to the results, both groups improved in visual perception function and in performance of activities of daily living. Although there was no significant difference between the two groups, the experimental group exhibited higher scores. [Conclusion] In conclusion, the application of tDCS for the rehabilitation of patients with stroke may positively affect their visual perception and ability to perform activities of daily living.

  14. Effect of transcranial direct current stimulation on visual perception function and performance capability of activities of daily living in stroke patients.

    Science.gov (United States)

    Kim, Ko-Un; Kim, Su-Han; An, Tae-Gyu

    2016-09-01

    [Purpose] The purpose of this study was to examine the effects of transcranial direct current stimulation (tDCS) on visual perception and performance of activities of daily living in patients with stroke. [Subjects and Methods] Thirty subjects were assigned equally to a tDCS plus traditional occupational therapy group (experimental group) and a traditional occupational therapy group (control group). The intervention was implemented five times per week, 30 minutes each, for six weeks. In order to assess visual perception function before and after the intervention, the motor-free visual perception test (MVPT) was conducted, and in order to compare the performance of activities of daily living, the Functional Independence Measure scale was employed. [Results] According to the results, both groups improved in visual perception function and in performance of activities of daily living. Although there was no significant difference between the two groups, the experimental group exhibited higher scores. [Conclusion] In conclusion, the application of tDCS for the rehabilitation of patients with stroke may positively affect their visual perception and ability to perform activities of daily living.

  15. 有源纹波补偿电流平方降压型LED驱动电路%Step-down LED drive circuit based on active ripple compensation and current square control

    Institute of Scientific and Technical Information of China (English)

    胡成龙; 薛凌云

    2012-01-01

    The ideal way to drive LED is constant current driving, and the electrolytic capacitor for filtering is adopted in output terminal, but the life-span of electrolytic capacitor cannot match well with the LED's. Peak current control is a commonly used control mode to realize the constant driving for LED, but peak current control can only control the peak current which flows through the LED and can not precisely control its average current, thus the luminous efficiency and reliability of LED are greatly affected. Aiming at solving these problems, the active ripple compensation structure omitting the filter capacitor and the current square control technique were applied in LED's driving circuit Based on the average current, controlled by the current square control technique and the current ripple compensated by the active ripple compensation structure, the working principle of the driving circuit was researched and analyzed, and the simulation based on PSIM6. 0 and the physical simulation was carried out at last. The simulation results indicate that the current square control technique can precisely control the average current, and the active ripple compensation structure can fully compensate the current ripple which results from omitting the filter capacitor and makes the LED's current approximately const.%LED理想的驱动方式是恒流驱动,在输出端常采用电解电容进行滤波,但电解电容的寿命与LED寿命不匹配;峰值电流控制是实现恒流驱动的常用控制方式,但该方式仅控制了流过LED的峰值电流,而未精确地控制其平均电流,这对LED的发光效率、可靠性等都有较大的影响.为解决以上问题,将省略了滤波电容的有源纹波补偿电路结构与电流平方控制技术应用于LED驱动电路中,基于电流平方控制对平均电流的控制,以及有源纹波补偿电路对纹波电流的补偿,开展了该驱动电路工作原理的研究及分析,并基于PSIM6.0进行了仿真验证,

  16. 无刷直流电动机的正弦波电流驱动方法%Sine-wave Current Drive Method for Brushless DC Motors

    Institute of Scientific and Technical Information of China (English)

    朱信舜; 林明耀; 刘文勇

    2011-01-01

    分析了无刷直流电动机方波驱动方式和传统正弦波驱动方式的优缺点,利用三相Hall信号,得到正弦波电流的周期和幅值,通过软件算法生成六路SVPWM信号来驱动无刷直流电动机.采用数字信号控制器(DSC)dsPIC30F4011作为主控芯片,设计了无刷直流电动机的控制系统,详细分析了SVPWM波的生成方法,并给出了软件流程.实验结果验证了提出方法的正确性和可行性.%The performances of square-wave drive and sine-wave drive of brushless DC motor( BLDCM) were analyzed in this paper, a method to drive the BLDCM which makes use of three-phase Hall position signals to get the cycle and magnitude of the sine-wave and a proper software program to generate six-way SVPWM waves was presented. Adopting the DSC dsPIC30F4011, the control system of BLDCM was designed. The method to get SVPWM wave was analyzed in detail in the paper, and the software flow chart was also given. Experimental results verified the validity and feasibility of the proposed method.

  17. Assessing the Driver’s Current Level of Working Memory Load with High Density Functional Near-infrared Spectroscopy: A Realistic Driving Simulator Study

    Directory of Open Access Journals (Sweden)

    Anirudh Unni

    2017-04-01

    Full Text Available Cognitive overload or underload results in a decrease in human performance which may result in fatal incidents while driving. We envision that driver assistive systems which adapt their functionality to the driver’s cognitive state could be a promising approach to reduce road accidents due to human errors. This research attempts to predict variations of cognitive working memory load levels in a natural driving scenario with multiple parallel tasks and to reveal predictive brain areas. We used a modified version of the n-back task to induce five different working memory load levels (from 0-back up to 4-back forcing the participants to continuously update, memorize, and recall the previous ‘n’ speed sequences and adjust their speed accordingly while they drove for approximately 60 min on a highway with concurrent traffic in a virtual reality driving simulator. We measured brain activation using multichannel whole head, high density functional near-infrared spectroscopy (fNIRS and predicted working memory load level from the fNIRS data by combining multivariate lasso regression and cross-validation. This allowed us to predict variations in working memory load in a continuous time-resolved manner with mean Pearson correlations between induced and predicted working memory load over 15 participants of 0.61 [standard error (SE 0.04] and a maximum of 0.8. Restricting the analysis to prefrontal sensors placed over the forehead reduced the mean correlation to 0.38 (SE 0.04, indicating additional information gained through whole head coverage. Moreover, working memory load predictions derived from peripheral heart rate parameters achieved much lower correlations (mean 0.21, SE 0.1. Importantly, whole head fNIRS sampling revealed increasing brain activation in bilateral inferior frontal and bilateral temporo-occipital brain areas with increasing working memory load levels suggesting that these areas are specifically involved in workload

  18. 步进驱动器高压恒流过程与参数计算%High-Voltage Constant-Current Process and Parameter Calculation for Stepper Motor Drives

    Institute of Scientific and Technical Information of China (English)

    张文明

    2011-01-01

    To solve the problem of torque decrease at low or high speed,a new three-phase hybrid stepper motor drive was developed. All the hardware circuit and software program of the drive were presented. With the new device,the hardware circuit parameters,critical data and software design were analyzed in detail. Meanwhile a comprehesive explanation of the PLC,logic control,constant cruuent control,high voltage drive,current sampling,over current protection and power supply ciruit was put forward, which is of a certain reference value.%针对步进电动机在低速和高速转矩下降的问题,开发出一种新型三相混合式步进电动机驱动器.给出驱动器全部硬件电路和软件程序,结合新器件应用,对硬件电路参数、关键数据、软件设计进行详实分析,全面剖析了单片机、逻辑控制、恒流控制、高压驱动、电流采样、过压保护、供电电源电路等,具有一定参考价值.

  19. Determining your organization's 'risk capability'.

    Science.gov (United States)

    Hannah, Bill; Hancock, Melinda

    2014-05-01

    An assessment of a provider's level of risk capability should focus on three key elements: Business intelligence, including sophisticated analytical models that can offer insight into the expected cost and quality of care for a given population. Clinical enterprise maturity, marked by the ability to improve health outcomes and to manage utilization and costs to drive change. Revenue transformation, emphasizing the need for a revenue cycle platform that allows for risk acceptance and management and that provides incentives for performance against defined objectives.

  20. Feedback control of current drive by using hybrid wave in tokamaks; Asservissement de la generation de courant par l`onde hybride dans un plasma de tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Wijnands, T.J. [Association Euratom-CEA, Centre d`Etudes Nucleaires de Cadarache, 13 - Saint-Paul-lez-Durance (France). Dept. de Recherches sur la Fusion Controlee]|[CEA Centre d`Etudes de Cadarache, 13 - Saint-Paul-lez-Durance (France). Direction des Sciences de la Matiere

    1997-03-01

    This work is focussed on an important and recent development in present day Controlled Nuclear Fusion Research and Tokamaks. The aim is to optimise the energy confinement for a certain magnetic configuration by adapting the radial distribution of the current. Of particular interest are feedback control scenarios with stationary modifications of the current profile using current, driven by Lower Hybrid waves. A new feedback control system has been developed for Tore Supra and has made a large number of new operation scenarios possible. In one of the experiments described here, there is no energy exchange between the poloidal field system and the plasma, the current is controlled by the power of the Lower Hybrid waves while the launched wave spectrum is used to optimise the current profile shape and the energy confinement. (author) 151 refs.

  1. CLIC Drive Beam Phase Stabilisation

    CERN Document Server

    Gerbershagen, Alexander; Schulte, Daniel

    The thesis presents phase stability studies for the Compact Linear Collider (CLIC) and focuses in particular on CLIC Drive Beam longitudinal phase stabilisation. This topic constitutes one of the main feasibility challenges for CLIC construction and is an essential component of the current CLIC stabilisation campaign. The studies are divided into two large interrelated sections: the simulation studies for the CLIC Drive Beam stability, and measurements, data analysis and simulations of the CLIC Test Facility (CTF3) Drive Beam phase errors. A dedicated software tool has been developed for a step-by-step analysis of the error propagation through the CLIC Drive Beam. It uses realistic RF potential and beam loading amplitude functions for the Drive and Main Beam accelerating structures, complete models of the recombination scheme and compressor chicane as well as of further CLIC Drive Beam modules. The tool has been tested extensively and its functionality has been verified. The phase error propagation at CLIC h...

  2. Improving the Current DHS Capabilities Framework

    Science.gov (United States)

    2008-09-01

    Laboratories ( PNL ) to establish the standards for the NIMS initiative. This entire situation creates another set of inconsistencies in criteria for...www.hsaj.org/?fullarticle=1.2.2, (accessed June 12, 2007), 8. 24 setting agencies: NFPA, PNL , American National Standards Institute (ANSI), and...with Pacific Northwest Laboratory ( PNL ) to develop the NIC standards. The Incident Management Standards Working Group (IMSWG) was established

  3. [Current capabilities of telemedicine in anaesthesiology].

    Science.gov (United States)

    Czaplik, M; Brokmann, J; Hochhausen, N; Beckers, S K; Rossaint, R

    2015-03-01

    Because of an ageing population and a relative lack of professionals, the German health system is under great pressure. In rural regions in particular, anesthesiology is also affected - nursing staff, anesthetists, intensive care physicians, and emergency physicians often have to be supported by freelancers from other regions and from abroad - at least periodically. In addition to the increasing number of treatments, the potential quality of therapy is also increasing owing to progress in medical research. Against this background the need for resources is increasing to ensure the optimal quality of treatment. This applies to all clinical disciplines, including all sections of anesthesiology - especially in economically underdeveloped regions where highly qualified experts are lacking. In various cases it is not the physical attendance or manual skills of experts that is primarily requested on-site, but rather their medical expertise and experience. Therefore, telemedicine systems are suitable for closing these gaps very effectively and efficiently. In the various anesthesiological sub-sections the number of scientific papers published to date varies. For anesthesia and pain therapy only a few telemedical applications or concepts have been reported in the literature. However, in tele-intensive care medicine and tele-emergency medicine several national and international research projects have successfully been carried out, leading to established routine systems in some cases.

  4. Radiofrequency current source (RFCS) drive and decoupling technique for parallel transmit arrays using a high-power metal oxide semiconductor field-effect transistor (MOSFET).

    Science.gov (United States)

    Lee, Wonje; Boskamp, Eddy; Grist, Thomas; Kurpad, Krishna

    2009-07-01

    A radiofrequency current source (RFCS) design using a high-power metal oxide semiconductor field effect transistor (MOSFET) that enables independent current control for parallel transmit applications is presented. The design of an RFCS integrated with a series tuned transmitting loop and its associated control circuitry is described. The current source is operated in a gated class AB push-pull configuration for linear operation at high efficiency. The pulsed RF current amplitude driven into the low impedance transmitting loop was found to be relatively insensitive to the various loaded loop impedances ranging from 0.4 to 10.3 ohms, confirming current mode operation. The suppression of current induced by a neighboring loop was quantified as a function of center-to-center loop distance, and was measured to be 17 dB for nonoverlapping, adjacent loops. Deterministic manipulation of the B(1) field pattern was demonstrated by the independent control of RF phase and amplitude in a head-sized two-channel volume transmit array. It was found that a high-voltage rated RF power MOSFET with a minimum load resistance, exhibits current source behavior, which aids in transmit array design.

  5. Maximizing MST's inductive capability with a Bp programmable power supply

    Science.gov (United States)

    Chapman, B. E.; Holly, D. J.; Jacobson, C. M.; McCollam, K. J.; Morin, J. C.; Sarff, J. S.; Squitieri, A.

    2016-10-01

    A major goal of the MST program is the advancement of inductive control for the development of both the RFP's fusion potential and, synergistically, the predictive capability of fusion science. This entails programmable power supplies (PPS's) for the Bt and Bp circuits. A Bt PPS is already in place, allowing advanced RFP operation and the production of tokamak plasmas, and a Bp PPS prototype is under construction. To explore some of the new capabilities to be provided by the Bp PPS, the existing Bt PPS has been temporarily connected to the Bp circuit. One key result is new-found access to very low Ip (20 kA) and very low Lundquist number, S (104). At this low S, simulation of RFP plasmas with the MHD code NIMROD is readily achievable, and work toward validation of extended MHD models using NIMROD is underway with direct comparisons to these MST plasmas. The full Bp PPS will also provide higher Ip and S than presently possible, allowing MST to produce plasmas with S spanning as much as five orders of magnitude, a dramatic extension of MST's capability. In these initial tests, the PPS has also increased five-fold MST's Ip flattop duration, to about 100 ms. This, coupled with the recently demonstrated PPS ability to drive large-amplitude sinusoidal oscillations in Ip, will allow tests of extended-duration oscillating field current drive, the goal of which is ac sustainment of a quasi-dc plasma current. Work supported by US DOE.

  6. Behavioure of high energy electrons on tokamak with low hybrid current drive%托卡马克中低杂波电流驱动下高能电子行为分析

    Institute of Scientific and Technical Information of China (English)

    竹锦霞

    2016-01-01

    Fast electrons and runaway electrons constitute the high-energy tail of electron maxwell distribution during low hy-brid current drive. High energy fast electron can effectively carry current driving to achieve no-induced current drive due to low collision frequency. But under certain conditions,fast electron can turn into runaway electron. It will damage to the device first wall material. This paper studies fast electron distribution and the runaway electrons generation by means of fast electron bremsstrahlung array and runaway electron diagnose. The conversion phenomenon from fast electron to runaway electron can be analyzed.%在低杂波电流驱动下,快电子和逃逸电子构成了非麦克斯韦电子分布的高能尾部。高能快电子由于低的碰撞频率可以有效的携带电流来实现非感应电流驱动。但是在一定条件下,快电子可以转化为高能逃逸电子,这将对装置第一壁材料造成损伤。本文利用快电子轫致辐射测量以及逃逸电子诊断系统研究了低杂波电流驱动下快电子分布和逃逸电子的产生,并分析了快电子转化为逃逸电子的现象。

  7. Neutral-point current modeling and control for Neutral-Point Clamped three-level converter drive with small DC-link capacitors

    DEFF Research Database (Denmark)

    Maheshwari, Ram Krishan; Munk-Nielsen, Stig; Busquets-Monge, Sergio

    2011-01-01

    -point current. A new simplified model of the neutral-point voltage dynamics is derived for the proposed modulation strategy. This model shows that the neutral-point current is proportional to the power drawn from the converter and it enables the use of well established classical control theory for neutral......-point voltage controller design. A PI controller is used for neutral-point voltage balance. The implementation of the proposed modulation strategy and controller is simple. It does not require any information about the output phase currents. The controller is implemented in a 7.5 kW induction machine based...

  8. Motor Integrated Variable Speed Drives

    DEFF Research Database (Denmark)

    Singh, Yash Veer

    A new trend in the variable speed drives (VSDs) is to develop fully integrated systems, which lead to low-cost products with shorter design cycles. Motor Integrated design of VSDs will reduce cable length to connect drive with machine windings and installation time for end user. The electric drives...... are expected to have minimum effect on grid and motor connected to it, i.e. currents drawn from grid should be within specified limits and currents injecting in to machine should not overheat the machine windings to avoid insulation failure due to harmonics. It is also necessary that electric drives should...... when it comes to the development of any kind of power converter topology for power electronic applications. Concerning the use of a power converter in motor integrated VSDs, the first two mentioned aspects receive an even greater im-portance. Power converter design for integrated drives poses a host...

  9. State of the Art Report for Development of Control Element Drive Mechanism of the APR+ Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jae Seon; Choi, Suhn; Song, Chul Hwa

    2008-10-15

    Recently newly-developed nuclear reactors with increased safety and enhanced performance by developed countries in the nuclear area are competing in the global nuclear market. Several reactors, for example AP600 and AP1000 by Westinghouse Electric Co. in USA, EPR by Areva in Europe, APWR by Mitsubishi Heavy Industry in Japan in the pressurized power reactor, are competing to preoccupy the nuclear market during Nuclear Renaissance. Dedicated control element drive mechanism with enhanced performance and increased safety are developed for these new reactors. And load follow capability is required, and it is estimated that load follow requirement make design requirement of a control element drive mechanism harsh. It is necessary to review the current technical state of a control element drive mechanism. This work is aimed to review the design characteristics of a past and current control element drive mechanism for a nuclear reactor and to check the direction and goal of CEDM design development recently.

  10. Neutral-point current modeling and control for Neutral-Point Clamped three-level converter drive with small DC-link capacitors

    DEFF Research Database (Denmark)

    Maheshwari, Ram Krishan; Munk-Nielsen, Stig; Busquets-Monge, Sergio

    2011-01-01

    A Neutral-Point-Clamped (NPC) three-level inverter with small DC-link capacitors is presented in this paper. This inverter requires zero average neutral-point current for stable neutral-point potential. A simple carrier based modulation strategy is proposed for achieving zero average neutral-poin...

  11. An Inverter Packaging Scheme for an Integrated Segmented Traction Drive System

    Energy Technology Data Exchange (ETDEWEB)

    Su, Gui-Jia [ORNL; Tang, Lixin [ORNL; Ayers, Curtis William [ORNL; Wiles, Randy H [ORNL

    2013-01-01

    The standard voltage source inverter (VSI), widely used in electric vehicle/hybrid electric vehicle (EV/HEV) traction drives, requires a bulky dc bus capacitor to absorb the large switching ripple currents and prevent them from shortening the battery s life. The dc bus capacitor presents a significant barrier to meeting inverter cost, volume, and weight requirements for mass production of affordable EVs/HEVs. The large ripple currents become even more problematic for the film capacitors (the capacitor technology of choice for EVs/HEVs) in high temperature environments as their ripple current handling capability decreases rapidly with rising temperatures. It is shown in previous work that segmenting the VSI based traction drive system can significantly decrease the ripple currents and thus the size of the dc bus capacitor. This paper presents an integrated packaging scheme to reduce the system cost of a segmented traction drive.

  12. A model of the plasma flow and current in Saturn's polar ionosphere under conditions of strong Dungey cycle driving

    Directory of Open Access Journals (Sweden)

    C. M. Jackman

    2006-05-01

    Full Text Available We propose a simple model of the flow and currents in Saturn's polar ionosphere. This model is motivated by theoretical reasoning, and guided quantitatively by in situ field and flow data from space missions, ground-based IR Doppler measurements, and Hubble Space Telescope images. The flow pattern consists of components which represent (1 plasma sub-corotation in the middle magnetosphere region resulting from plasma pick-up and radial transport from internal sources; (2 the Vasyliunas-cycle of internal plasma mass-loss down the magnetospheric tail at higher latitudes; and (3 the polar Dungey-cycle flow driven by the solar wind interaction. Upstream measurements of the interplanetary magnetic field (IMF indicate the occurrence of both extended low-field rarefaction intervals with essentially negligible Dungey-cycle flow, and few-day high-field compression regions in which the Dungey-cycle voltage peaks at a few hundred kV. Here we model the latter conditions when the Dungey-cycle is active, advancing on previous axi-symmetric models which may be more directly applicable to quiet conditions. For theoretical convenience the overall flow pattern is constructed by adding together two components - a purely rotational flow similar to previous axi-symmetric models, and a sun-aligned twin vortex representing the dawn-dusk asymmetry effects associated with the Vasyliunas-and Dungey-cycle flows. We calculate the horizontal ionospheric current associated with the flow and the field-aligned current from its divergence. These calculations show that a sheet of upward-directed field-aligned current flows at the boundary of open field lines which is strongly modulated in local-time by the Dungey-cycle flows. We then consider implications of the field-aligned current for magnetospheric electron acceleration and aurorae using two plasma source populations (hot outer magnetospheric electrons and cool dense magnetosheath electrons. Both sources display a

  13. Development of hybrid frequency couplers for non-inductive current drive in a tokamak; Developpement de coupleurs a la frequence hybride pour la generation non inductive du courant dans un tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Berio, St.

    1996-11-04

    Used at its first time as an heating method in order to reach the temperature requisite for the fusion of a thermonuclear plasma, the hybrid waves has shown that they were the more efficient method for non-inductive current drive in a tokamak. The size and the objectives of a next machine such as ITER lead of the design of new antennae (in process of realisation on Tore Supra) made of oversized waveguides. This new concept of antenna will be more simple, more robust and will be able to transmit the same if not much power than the present antennae. This thesis contribute to the development of a new code called ALOHA (for `Advanced LOwer Hybrid Antenna`) which, at the end, will be able to give the characteristics and the behaviours of this new oversized antennae in front of a tokamak plasma. This thesis is also a first step in the interpretation of some experimental data concerning the measurement of coupling, absorption and current drive of the actual hybrid wave launched by a grill with rectangular waveguides. Moreover, this thesis lay some foundations of the study of these new antennae in front of a non-parallel confinement magnetic field and/or in front of poloidal inhomogeneities of plasma. (author). 53 refs.

  14. Capability Development in an Offshoring Context

    DEFF Research Database (Denmark)

    Jaura, Manya

    Capability development can be defined as deliberate firm-level investment involving a search and learning process aimed at modifying or enhancing existing capabilities. Increasingly, firms are relocating advanced services to offshore locations resulting in the challenge of capability development...... in the offshore unit. Guided by the research question – what drives or impedes capability development in an offshoring context – the purpose of this thesis is to investigate how an idiosyncratic offshoring context affects capability development. The thesis consists of three papers using various datasets...... and qualitative methods that investigate capability development in an offshoring context. The first paper investigates how capability development takes place for a service-provider firm at the activity level. The second paper examines the transition made by a captive offshore unit, from performing standardized...

  15. STRATEGIC AIRLIFT CAPABILITY: FROM THEORY TO PRACTICE

    OpenAIRE

    Cezar VASILESCU

    2011-01-01

    Strategic airlift remains a critical supporting capability that should be achieved, maintained and improved. This capability ensures the ability to deploy and sustain military forces across possible distant battlefields. The paper analyses the growing strategic airlift capabilities gap between operational needs and current realities, and underlines the need for an enhanced strategic airlift capability to meet current and future NATO alliance needs. By analyzing requirements against the existi...

  16. Mobile Test Capabilities

    Data.gov (United States)

    Federal Laboratory Consortium — The Electrical Power Mobile Test capabilities are utilized to conduct electrical power quality testing on aircraft and helicopters. This capability allows that the...

  17. The refurbished Z facility : capabilities and recent experiments.

    Energy Technology Data Exchange (ETDEWEB)

    Leeper, Ramon Joe; Long, Finis W.; Leifeste, Gordon T.; Hall, Clint Allen; Atherton, Briggs W.; Herrmann, Mark C.; Donovan, Guy Louis; McKee, G. Randall; Weinbrecht, Edward A.; Porter, John Larry, Jr.; Mehlhorn, Thomas Alan; Cuneo, Michael Edward; Struve, Kenneth William; Stygar, William A.; Kiefer, Mark Linden; Matzen, Maurice Keith; Schneider, Larry X.

    2008-09-01

    The Z Refurbishment Project was completed in September 2007. Prior to the shutdown of the Z facility in July 2006 to install the new hardware, it provided currents of {le} 20 MA to produce energetic, intense X-ray sources ({approx} 1.6 MJ, > 200 TW) for performing high energy density science experiments and to produce high magnetic fields and pressures for performing dynamic material property experiments. The refurbishment project doubled the stored energy within the existing tank structure and replaced older components with modern, conventional technology and systems that were designed to drive both short-pulse Z-pinch implosions and long-pulse dynamic material property experiments. The project goals were to increase the delivered current for additional performance capability, improve overall precision and pulse shape flexibility for better reproducibility and data quality, and provide the capacity to perform more shots. Experiments over the past year have been devoted to bringing the facility up to full operating capabilities and implementing a refurbished suite of diagnostics. In addition, we have enhanced our X-ray backlighting diagnostics through the addition of a two-frame capability to the Z-Beamlet system and the addition of a high power laser (Z-Petawatt). In this paper, we will summarize the changes made to the Z facility, highlight the new capabilities, and discuss the results of some of the early experiments.

  18. Particle-in-cell simulations of an alpha channeling scenario: electron current drive arising from lower hybrid drift instability of fusion-born ions

    Science.gov (United States)

    Cook, James; Chapman, Sandra; Dendy, Richard

    2010-11-01

    Particle-in-cell (PIC) simulations of fusion-born protons in deuterium plasmas demonstrate a key alpha channeling phenomenon for tokamak fusion plasmas. We focus on obliquely propagating modes at the plasma edge, excited by centrally born fusion products on banana orbits, known to be responsible for observations of ion cyclotron emission in JET and TFTR. A fully self-consistent electromagnetic 1D3V PIC code evolves a ring-beam distribution of 3MeV protons in a 10keV thermal deuterium-electron plasma with realistic mass ratio. A collective instability occurs, giving rise to electromagnetic field activity in the lower hybrid range of frequencies. Waves spontaneously excited by this lower hybrid drift instability undergo Landau damping on resonant electrons, drawing out an asymmetric tail in the distribution of electron parallel velocities, which constitutes a net current. These simulations demonstrate a key building block of some alpha channeling scenarios: the direct collisionless coupling of fusion product energy into a form which can help sustain the equilibrium of the tokamak.

  19. IAC - INTEGRATED ANALYSIS CAPABILITY

    Science.gov (United States)

    Frisch, H. P.

    1994-01-01

    Integration via Mesh Interpolation Coefficients), which transforms field values from one model to another; LINK, which simplifies incorporation of user specific modules into IAC modules; and DATAPAC, the National Bureau of Standards statistical analysis package. The IAC database contains structured files which provide a common basis for communication between modules and the executive system, and can contain unstructured files such as NASTRAN checkpoint files, DISCOS plot files, object code, etc. The user can define groups of data and relations between them. A full data manipulation and query system operates with the database. The current interface modules comprise five groups: 1) Structural analysis - IAC contains a NASTRAN interface for standalone analysis or certain structural/control/thermal combinations. IAC provides enhanced structural capabilities for normal modes and static deformation analysis via special DMAP sequences. IAC 2.5 contains several specialized interfaces from NASTRAN in support of multidisciplinary analysis. 2) Thermal analysis - IAC supports finite element and finite difference techniques for steady state or transient analysis. There are interfaces for the NASTRAN thermal analyzer, SINDA/SINFLO, and TRASYS II. FEMNET, which converts finite element structural analysis models to finite difference thermal analysis models, is also interfaced with the IAC database. 3) System dynamics - The DISCOS simulation program which allows for either nonlinear time domain analysis or linear frequency domain analysis, is fully interfaced to the IAC database management capability. 4) Control analysis - Interfaces for the ORACLS, SAMSAN, NBOD2, and INCA programs allow a wide range of control system analyses and synthesis techniques. Level 2.5 includes EIGEN, which provides tools for large order system eigenanalysis, and BOPACE, which allows for geometric capabilities and finite element analysis with nonlinear material. Also included in IAC level 2.5 is SAMSAN 3.1, an

  20. Observation of a new turbulence-driven limit-cycle state in H-modes with lower hybrid current drive and lithium-wall conditioning in the EAST superconducting tokamak

    DEFF Research Database (Denmark)

    Wang, H.Q.; Xu, G.S.; Guo, H.Y.;

    2012-01-01

    -frequency oscillation, termed a limit-cycle state, appears at the edge during the quiescent phase with good energy and particle confinement. Detailed measurements by edge Langmuir probes show modulation interaction and strong three-wave coupling between the low-frequency oscillations and high-frequency-broadband (80......The first high confinement H-mode plasma has been obtained in the Experimental Advanced Superconducting Tokamak (EAST) with about 1 MW lower hybrid current drive after wall conditioning by lithium evaporation and real-time injection of Li powder. Following the L–H transition, a small-amplitude, low....... And the measurements demonstrate that the energy gain of zonal flows is of the same order as the energy loss of turbulence. This strongly suggests the interactions between zonal flows and high-frequency turbulences at the pedestal during the limit-cycle state....

  1. Mild cognitive impairment: safe to drive?

    Science.gov (United States)

    Olsen, Kirsty; Taylor, John-Paul; Thomas, Alan

    2014-06-01

    Driving is an important aspect of daily living and for many older people provides autonomy and psycho-social benefits. Cognitive impairment has been found to impact driving skills at the level of dementia, however, uncertainty remains around the impact of a diagnosis of the pre-dementia condition mild cognitive impairment. Current official guidelines are unclear, and assessment of fitness to drive can be problematical. This editorial examines current official guidance available to the clinician and problems with existing assessment as well as the current position of research specifically into MCI and driving, and considers future direction for research in this field.

  2. Self-Tuning Speed Regulator for CVC Induction Motor Drive

    DEFF Research Database (Denmark)

    Bidstrup, N.; Rasmussen, Henrik; Knudsen, Torben

    1994-01-01

    A self-tuning speed regulator for a current vector controlled induction motor drive has been designed.......A self-tuning speed regulator for a current vector controlled induction motor drive has been designed....

  3. Dynamic capabilities, Marketing Capability and Organizational Performance

    Directory of Open Access Journals (Sweden)

    Adriana Roseli Wünsch Takahashi

    2017-01-01

    Full Text Available The goal of the study is to investigate the influence of dynamic capabilities on organizational performance and the role of marketing capabilities as a mediator in this relationship in the context of private HEIs in Brazil. As a research method we carried out a survey with 316 IES and data analysis was operationalized with the technique of structural equation modeling. The results indicate that the dynamic capabilities have influence on organizational performance only when mediated by marketing ability. The marketing capability has an important role in the survival, growth and renewal on educational services offerings for HEIs in private sector, and consequently in organizational performance. It is also demonstrated that mediated relationship is more intense for HEI with up to 3,000 students and other organizational profile variables such as amount of courses, the constitution, the type of institution and type of education do not significantly alter the results.

  4. Research on Characteristic of Sinusoidal Current Driving Method for BLDCM with Hall Position Sensor%基于Hall位置传感器的BLDCM正弦波驱动性能研究

    Institute of Scientific and Technical Information of China (English)

    马瑞卿; 邓钧君

    2011-01-01

    Adriving method of Brushless DC Motor (BLDCM) with sinusoidal current was presented. Space vector pulse width modulation ( SVPWM) techniques was adopted to generate sinusoidal current for motor three-phase windings according to the rotor position information provided by three-phase Hall sensors. The experimental results show that the approach is more effective for the minimization of the torque ripple and audible noise than the traditional square current driving method, and practical for quiet operation in low cost home appliances.%针对稀土永磁无刷直流电机( BLDCM),借助电机本体所固有的三相Hall转子位置传感器,通过空间矢量脉宽调制(SVPWM)控制技术,实现了BLDCM的正弦波电流驱动.实验结果表明,与方波电流驱动相比,采用正弦波驱动可有效减小BLDCM的运行噪声,降低转矩脉动,实现低成本家用电器等领域的静音运行.

  5. Automated driving safer and more efficient future driving

    CERN Document Server

    Horn, Martin

    2017-01-01

    The main topics of this book include advanced control, cognitive data processing, high performance computing, functional safety, and comprehensive validation. These topics are seen as technological bricks to drive forward automated driving. The current state of the art of automated vehicle research, development and innovation is given. The book also addresses industry-driven roadmaps for major new technology advances as well as collaborative European initiatives supporting the evolvement of automated driving. Various examples highlight the state of development of automated driving as well as the way forward. The book will be of interest to academics and researchers within engineering, graduate students, automotive engineers at OEMs and suppliers, ICT and software engineers, managers, and other decision-makers.

  6. Antihistamines and driving ability: Evidence from 30 years Dutch on-road driving research

    NARCIS (Netherlands)

    Verster, J.C.; Van De Loo, A.J.A.E.; Garssen, J.

    2015-01-01

    Background: Since all antihistamines are capable of crossing the blood-brain barrier, they may also cause sedation which may impair daily activities such as driving a car. The purpose of this review was to examine the effects of antihistamines on driving ability. Method: A literature search revealed

  7. Calculation of Excitation Current for Turbo Generator Based on Excel VBA Drive Maxwell%基于Excel VBA驱动Maxwell的汽轮发电机励磁电流计算∗

    Institute of Scientific and Technical Information of China (English)

    罗玉东; 徐余法; 陈亚新; 房建俊

    2016-01-01

    Excitation current is one of the main operating data of turbo generator, it directly affects the performance of the generator. Accroding to the feature of turbo generataor and the principle of excitation current calculation, an example of 600 MW tubro generator was taken, building the field current calculation model of tubro generator, calculating the rated load excitation current with magnetostatic field and transient field. Design the software that Excel VBA drive Maxwell to calculate the excitation current. Not could the software build the model of generator parametrically,but also realized the iterative calucation of field current atuomatically. The software had the features of creating model and calculating excitation current with one button, the difficulty of field current calculation was reduced and the generator’s development cycles was shorten, realizing the value of engineering applications.%励磁电流是汽轮发电机的主要运行数据之一,其大小直接影响发电机的运行性能。根据汽轮发电机的模型特点及励磁电流计算的原理,以一台600 MW汽轮发电机为例,建立发电机励磁电流计算模型,计算了静磁场和瞬态场下的额定负载励磁电流;并用Excel VBA编写计算程序,让Excel VBA驱动Maxwell有限元软件计算励磁电流。该程序不仅能参数化建模,还能实现励磁电流有限元计算的自动迭代,具有一键式建模和一键式求解功能,降低了励磁电流计算难度,缩短了汽轮发电机的研发周期,实现工程应用价值。

  8. IAC - INTEGRATED ANALYSIS CAPABILITY

    Science.gov (United States)

    Frisch, H. P.

    1994-01-01

    Integration via Mesh Interpolation Coefficients), which transforms field values from one model to another; LINK, which simplifies incorporation of user specific modules into IAC modules; and DATAPAC, the National Bureau of Standards statistical analysis package. The IAC database contains structured files which provide a common basis for communication between modules and the executive system, and can contain unstructured files such as NASTRAN checkpoint files, DISCOS plot files, object code, etc. The user can define groups of data and relations between them. A full data manipulation and query system operates with the database. The current interface modules comprise five groups: 1) Structural analysis - IAC contains a NASTRAN interface for standalone analysis or certain structural/control/thermal combinations. IAC provides enhanced structural capabilities for normal modes and static deformation analysis via special DMAP sequences. IAC 2.5 contains several specialized interfaces from NASTRAN in support of multidisciplinary analysis. 2) Thermal analysis - IAC supports finite element and finite difference techniques for steady state or transient analysis. There are interfaces for the NASTRAN thermal analyzer, SINDA/SINFLO, and TRASYS II. FEMNET, which converts finite element structural analysis models to finite difference thermal analysis models, is also interfaced with the IAC database. 3) System dynamics - The DISCOS simulation program which allows for either nonlinear time domain analysis or linear frequency domain analysis, is fully interfaced to the IAC database management capability. 4) Control analysis - Interfaces for the ORACLS, SAMSAN, NBOD2, and INCA programs allow a wide range of control system analyses and synthesis techniques. Level 2.5 includes EIGEN, which provides tools for large order system eigenanalysis, and BOPACE, which allows for geometric capabilities and finite element analysis with nonlinear material. Also included in IAC level 2.5 is SAMSAN 3.1, an

  9. 永磁同步电动机的直接滑模电流控制研究%Study on Permanent Magnet Synchronous Machine Drive System Based on Direct Sliding Mode Current Control

    Institute of Scientific and Technical Information of China (English)

    肖甘

    2013-01-01

    本文以永磁同步电动机为基础,研究了直接滑模电流控制策略,该策略对参数变化以及外界干扰的鲁棒性较强,从而广泛应用于电气传动控制领域.设计了新颖的直接滑模电流控制器代替传统的PI电流控制器,并且采用了开关表查询方式加快了动态响应速度.最后基于TMS320DSP28335控制器对永磁同步电动机直接滑模电流控制控制系统进行实验验证,结果表明所设计的控制器动态响应较快,抗干扰能力较强.%This paper researched on direct sliding mode current control of a permanent magnet synchronous machine.Due to the robustness to parameters variations and external disturbances,sliding mode controllers were widely used for the control of electrical drives.A novel direct sliding mode current controller was designed to substitute the traditional PI current controller,and switch table was used to speed up the dynamic response.As a result,the experiment of permanent magnet synchronous machine direct sliding mode current control system based on TMS320DSP28335 controller was finished.The experimental results illustrate this designed controller has faster dynamic response and stronger anti-interference ability.

  10. Noninvasive biological sensor system for detection of drunk driving.

    Science.gov (United States)

    Murata, Kohji; Fujita, Etsunori; Kojima, Shigeyuki; Maeda, Shinitirou; Ogura, Yumi; Kamei, Tsutomu; Tsuji, Toshio; Kaneko, Shigehiko; Yoshizumi, Masao; Suzuki, Nobutaka

    2011-01-01

    Systems capable of monitoring the biological condition of a driver and issuing warnings during instances of drowsiness have recently been studied. Moreover, many researchers have reported that biological signals, such as brain waves, pulsation waves, and heart rate, are different between people who have and have not consumed alcohol. Currently, we are developing a noninvasive system to detect individuals driving under the influence of alcohol by measuring biological signals. We used the frequency time series analysis to attempt to distinguish between normal and intoxicated states of a person as the basis of the sensing system.

  11. Behavioral and neurophysiological signatures of benzodiazepine-related driving impairments

    Directory of Open Access Journals (Sweden)

    Bradly T Stone

    2015-11-01

    Full Text Available Impaired driving due to drug use is a growing problem, worldwide; estimates show that 18-23.5% of fatal accidents, and up to 34% of injury accidents may be caused by drivers under the influence of drugs (Drummer et al., 2003; NHTSA, 2010; Walsh et al., 2004. Furthermore, at any given time, up to 16% of drivers may be using drugs that can impair one’s driving abilities (NHTSA, 2009. Currently, drug recognition experts (law enforcement officers with specialized training to identify drugged driving, have the most difficult time with identifying drivers potentially impaired on central nervous system (CNS depressants (Smith, Hayes, Yolton, Rutledge, & Citek, 2002. The fact that the use of benzodiazepines, a type of CNS depressant, is also associated with the greatest likelihood of causing accidents (Dassanayake, Michie, Carter, & Jones, 2011, further emphasizes the need to improve research tools in this area which can facilitate the refinement of, or additions to, current assessments of impaired driving. Our laboratories collaborated to evaluate both the behavioral and neurophysiological effects of a benzodiazepine, alprazolam, in a driving simulation (miniSim™. This drive was combined with a neurocognitive assessment utilizing time synched neurophysiology (EEG, ECG. While the behavioral effects of benzodiazepines are well characterized (Rapoport et al., 2009, we hypothesized that, with the addition of real-time neurophysiology and the utilization of simulation and neurocognitive assessment, we could find objective assessments of drug impairment that could improve the detection capabilities of drug recognition experts. Our analyses revealed that 1 specific driving conditions were significantly more difficult for benzodiazepine impaired drivers and; 2 the neurocognitive tasks’ metrics were able to classify impaired vs. unimpaired with up to 80% accuracy based on lane position deviation and lane departures. While this work requires replication in

  12. Rotor speed estimation for indirect stator flux oriented induction motor drive based on MRAS scheme

    Directory of Open Access Journals (Sweden)

    Youssef Agrebi

    2007-09-01

    Full Text Available In this paper, a conventional indirect stator flux oriented controlled (ISFOC induction motor drive is presented. In order to eliminate the speed sensor, an adaptation algorithm for tuning the rotor speed is proposed. Based on the model reference adaptive system (MRAS scheme, the rotor speed is tuned to obtain an exact ISFOC induction motor drive. The reference and adjustable models, developed in stationary stator reference frame, are used in the MRAS scheme to estimate induction rotor peed from measured terminal voltages and currents. The IP gains speed controller and PI gains current controller are calculated and tuned at each sampling time according to the new estimated rotor speed. The proposed algorithm has been tested by numerical simulation, showing the capability of driving active load; and stability is preserved. Experimental results obtained with a general-purpose 1-kW induction machine are presented showing the effectiveness of the proposed approach in terms of dynamic performance.

  13. Computer Tensor Codes to Design the War Drive

    Science.gov (United States)

    Maccone, C.

    To address problems in Breakthrough Propulsion Physics (BPP) and design the Warp Drive one needs sheer computing capabilities. This is because General Relativity (GR) and Quantum Field Theory (QFT) are so mathematically sophisticated that the amount of analytical calculations is prohibitive and one can hardly do all of them by hand. In this paper we make a comparative review of the main tensor calculus capabilities of the three most advanced and commercially available “symbolic manipulator” codes. We also point out that currently one faces such a variety of different conventions in tensor calculus that it is difficult or impossible to compare results obtained by different scholars in GR and QFT. Mathematical physicists, experimental physicists and engineers have each their own way of customizing tensors, especially by using different metric signatures, different metric determinant signs, different definitions of the basic Riemann and Ricci tensors, and by adopting different systems of physical units. This chaos greatly hampers progress toward the design of the Warp Drive. It is thus suggested that NASA would be a suitable organization to establish standards in symbolic tensor calculus and anyone working in BPP should adopt these standards. Alternatively other institutions, like CERN in Europe, might consider the challenge of starting the preliminary implementation of a Universal Tensor Code to design the Warp Drive.

  14. A study on the effects of fatigue driving and drunk driving on drivers' physical characteristics.

    Science.gov (United States)

    Zhang, Xingjian; Zhao, Xiaohua; Du, Hongji; Rong, Jian

    2014-01-01

    are found to impair drivers' physical characteristics. However, their impacts on the parameters SBP, HR, eyesight, and TDSA are different. A driver's physical characteristics will be impaired more seriously when he continues driving while drowsy, compared to driving under normal situation. These findings contribute to the current research on identifying drivers' driving state and quantifying the effects of fatigue driving and drunk driving on driving ability and driving behavior.

  15. Capabilities for Strategic Adaptation

    DEFF Research Database (Denmark)

    Distel, Andreas Philipp

    This dissertation explores capabilities that enable firms to strategically adapt to environmental changes and preserve competitiveness over time – often referred to as dynamic capabilities. While dynamic capabilities being a popular research domain, too little is known about what these capabilities...... empirical studies through the dynamic capabilities lens and develops propositions for future research. The second paper is an empirical study on the origins of firm-level absorptive capacity; it explores how organization-level antecedents, through their impact on individual-level antecedents, influence...... firms’ ability to absorb and leverage new knowledge. The third paper is an empirical study which conceptualizes top managers’ resource cognition as a managerial capability underlying firms’ resource adaptation; it empirically examines the performance implications of this capability and organizational...

  16. An APC:WNT counter-current-like mechanism regulates cell division along the colonic crypt axis: a mechanism that explains how APC mutations induce proliferative abnormalities that drive colon cancer development.

    Directory of Open Access Journals (Sweden)

    Bruce M Boman

    2013-11-01

    Full Text Available APC normally down-regulates WNT signaling in human colon, and APC mutations cause proliferative abnormalities in premalignant crypts leading to colon cancer, but the mechanisms are unclear at the level of spatial and functional organization of the crypt. Accordingly, we postulated a counter-current-like mechanism based on gradients of factors (APC;WNT that regulate colonocyte proliferation along the crypt axis. During crypt renewal, stem cells (SCs at the crypt bottom generate non-SC daughter cells that proliferate and differentiate while migrating upwards. The APC concentration is low at the crypt bottom and high at the top (where differentiated cells reside. WNT signaling, in contrast, is high at the bottom (where SCs reside and low at the top. Given that WNT and APC gradients are counter to one another, we hypothesized that a counter-current-like mechanism exists. Since both APC and WNT signaling components (e.g. survivin are required for mitosis, this mechanism establishes a zone in the lower crypt where conditions are optimal for maximal cell division and mitosis orientation (symmetric versus asymmetric. APC haploinsufficiency diminishes the APC gradient, shifts the proliferative zone upwards, and increases symmetric division, which causes SC overpopulation. In homozygote mutant crypts, these changes are exacerbated. Thus, APC-mutation-induced changes in the counter-current-like mechanism cause expansion of proliferative populations (SCs, rapidly-proliferating cells during tumorigenesis. We propose this mechanism also drives crypt fission, functions in the crypt cycle, and underlies adenoma development. Novel chemoprevention approaches designed to normalize the two gradients and readjust the proliferative zone downwards, might thwart progression of these premalignant changes.

  17. CLIC Drive Beam Position Monitor

    CERN Document Server

    Smith, S; Gudkov, D; Soby, L; Syratchev, I

    2011-01-01

    CLIC, an electron-positron linear collider proposed to probe the TeV energy scale, is based on a two-beam scheme where RF power to accelerate a high energy luminosity beam is extracted from a high current drive beam. The drive beam is efficiently generated in a long train at modest frequency and current then compressed in length and multiplied in frequency via bunch interleaving. The drive beam decelerator requires >40000 quadrupoles, each holding a beam position monitor (BPM). Though resolution requirements are modest (2 microns) these BPMs face several challenges. They must be compact and inexpensive. They must operate below waveguide cutoff to insure locality of position signals, ruling out processing at the natural 12 GHz bunch spacing frequency. Wakefields must be kept low. We find compact conventional stripline BPM with signals processed below 40 MHz can meet requirements. Choices of mechanical design, operating frequency, bandwidth, calibration and processing algorithm are presented. Calculations of wa...

  18. Research on Institutional Driving Mechanism of International Marketing Dynamic Capabilities: A Case Study Based on the Internationalization Process of Sichuan Changhong%国际营销动态能力的制度驱动机制研究——基于四川长虹国际化进程的案例分析

    Institute of Scientific and Technical Information of China (English)

    李巍; 许晖

    2012-01-01

    随着国际市场动荡性的不断增强,国际化企业如何在持续变化的外部环境下获取和维持竞争优势成为战略营销研究的关注焦点;国际营销动态能力概念为企业应对激烈国际市场竞争提供了新的指导工具。本研究基于制度理论的视角,从管制、规范和文化认知三大系统中识别出若干制度因素;通过对四川长虹国际化进程的案例分析,考察了企业在不同国际化阶段驱动国际营销动态能力的关键因素及实现机制;最后对研究所提供的理论和实践启示进行讨论。%With the volatility of the international market continuing to strengthen, how interna- tional corporations could access and obtain a competitive advantage under a continuous changing environment has become an important research topic of the strategic marketing theory. The de- velopment of the concept of international marketing dynamic capabilities (IMDCs) provides a new tool for corporations to respond to the intense competition in the international market. From the perspective of institutional theory, this research identifies several institutional factors basing on the regulative, normative and cultural-cognitive systems, and examines the critical factors and working mechanism of institutional factors driving on the IMDCs in the corporation' s different in- ternationalization stages through the case study on the internationalization process of Sichuan Changhong. Finally, some theoretical and practical implications the findings provide are dis- cussed.

  19. Building Service Provider Capabilities

    DEFF Research Database (Denmark)

    Brandl, Kristin; Jaura, Manya; Ørberg Jensen, Peter D.

    In this paper we study whether and how the interaction between clients and the service providers contributes to the development of capabilities in service provider firms. In situations where such a contribution occurs, we analyze how different types of activities in the production process...... of the services, such as sequential or reciprocal task activities, influence the development of different types of capabilities. We study five cases of offshore-outsourced knowledge-intensive business services that are distinguished according to their reciprocal or sequential task activities in their production...... process. We find that clients influence the development of human capital capabilities and management capabilities in reciprocally produced services. While in sequential produced services clients influence the development of organizational capital capabilities and management capital capabilities....

  20. Developing Alliance Capabilities

    DEFF Research Database (Denmark)

    Heimeriks, Koen H.; Duysters, Geert; Vanhaverbeke, Wim

    capability. However, empirical testing in this field is scarce and little is known as to what extent different learning mechanisms are indeed useful in advancing a firm's alliance capability. This paper analyzes to what extent intra-firm learning mechanisms help firms develop their alliance capability......This paper assesses the differential performance effects of learning mechanisms on the development of alliance capabilities. Prior research has suggested that different capability levels could be identified in which specific intra-firm learning mechanisms are used to enhance a firm's alliance....... Differential learning may explain in what way firms yield superior returns from their alliances in comparison to competitors. The empirical results show that different learning mechanisms have different performance effects at different stages of the alliance capability development process. The main lesson from...

  1. CLIC Drive Beam Accelerating Structures

    CERN Document Server

    Wegner, Rolf

    2012-01-01

    Travelling structures for accelerating the high-current (4.2 A) CLIC Drive Beam to an energy of 2.37 GeV are presented. The structures are optimised for efficiency (full beam loading operation) and a desired filling time. Higher order modes are studied and are reduced by detuning along the structure and by damping with silicon carbide loads.

  2. Dynamic Capabilities and Performance

    DEFF Research Database (Denmark)

    Wilden, Ralf; Gudergan, Siegfried P.; Nielsen, Bo Bernhard

    2013-01-01

    Dynamic capabilities are widely considered to incorporate those processes that enable organizations to sustain superior performance over time. In this paper, we argue theoretically and demonstrate empirically that these effects are contingent on organizational structure and the competitive...... are contingent on the competitive intensity faced by firms. Our findings demonstrate the performance effects of internal alignment between organizational structure and dynamic capabilities, as well as the external fit of dynamic capabilities with competitive intensity. We outline the advantages of PLS...

  3. Flex: RSRE's capability computer

    Science.gov (United States)

    Foster, J. M.

    The Flex capability based computer architecture is described. It supports a multilanguage environment, and compilers for ALGOL 168 and PASCAL exist; an Ada compiler is being completed. The idea of capabilities is used on backing store as well as main store, so that all kinds of structured object which can be held in main store can also be held on any of the packing stores with the same degree of protection. Capabilities are used across a network of Flex computers, so that capabilities for data in one machine may be passed to and held in another. Flex uses true procedure values in the sense of Landin (1964).

  4. Integrated Process Capability Analysis

    Institute of Scientific and Technical Information of China (English)

    Chen; H; T; Huang; M; L; Hung; Y; H; Chen; K; S

    2002-01-01

    Process Capability Analysis (PCA) is a powerful too l to assess the ability of a process for manufacturing product that meets specific ations. The larger process capability index implies the higher process yield, a nd the larger process capability index also indicates the lower process expected loss. Chen et al. (2001) has applied indices C pu, C pl, and C pk for evaluating the process capability for a multi-process product wi th smaller-the-better, larger-the-better, and nominal-the-best spec...

  5. Driving, brain injury and assistive technology.

    Science.gov (United States)

    Lane, Amy K; Benoit, Dana

    2011-01-01

    Individuals with brain injury often present with cognitive, physical and emotional impairments which impact their ability to resume independence in activities of daily living. Of those activities, the resumption of driving privileges is cited as one of the greatest concerns by survivors of brain injury. The integration of driving fundamentals within the hierarchical model proposed by Keskinen represents the complexity of skills and behaviors necessary for driving. This paper provides a brief review of specific considerations concerning the driver with TBI and highlights current vehicle technology which has been developed by the automotive industry and by manufacturers of adaptive driving equipment that may facilitate the driving task. Adaptive equipment technology allows for compensation of a variety of operational deficits, whereas technological advances within the automotive industry provide drivers with improved safety and information systems. However, research has not yet supported the use of such intelligent transportation systems or advanced driving systems for drivers with brain injury. Although technologies are intended to improve the safety of drivers within the general population, the potential of negative consequences for drivers with brain injury must be considered. Ultimately, a comprehensive driving evaluation and training by a driving rehabilitation specialist is recommended for individuals with brain injury. An understanding of the potential impact of TBI on driving-related skills and knowledge of current adaptive equipment and technology is imperative to determine whether return-to-driving is a realistic and achievable goal for the individual with TBI.

  6. DriveID: safety innovation through individuation.

    Science.gov (United States)

    Sawyer, Ben; Teo, Grace; Mouloua, Mustapha

    2012-01-01

    The driving task is highly complex and places considerable perceptual, physical and cognitive demands on the driver. As driving is fundamentally an information processing activity, distracted or impaired drivers have diminished safety margins compared with non- distracted drivers (Hancock and Parasuraman, 1992; TRB 1998 a & b). This competition for sensory and decision making capacities can lead to failures that cost lives. Some groups, teens and elderly drivers for example, have patterns of systematically poor perceptual, physical and cognitive performance while driving. Although there are technologies developed to aid these different drivers, these systems are often misused and underutilized. The DriveID project aims to design and develop a passive, automated face identification system capable of robustly identifying the driver of the vehicle, retrieve a stored profile, and intelligently prescribing specific accident prevention systems and driving environment customizations.

  7. Control and Driving Methods for LED Based Intelligent Light Sources

    DEFF Research Database (Denmark)

    Beczkowski, Szymon

    High power light-emitting diodes allow the creation of luminaires capable of generating saturated colour light at very high efficacies. Contrary to traditional light sources like incandescent and high-intensity discharge lamps, where colour is generated using filters, LEDs use additive light mixing......, where the intensity of each primary colour diode has to be adjusted to the needed intensity to generate specified colour. The function of LED driver is to supply the diode with power needed to achieve the desired intensity. Typically, the drivers operate as a current source and the intensity...... current. The model can also be used to create highly accurate luminaire model. Finally, a dual interleaved buck converter has been proposed for driving high power light-emitting diodes. Interleaving two converters lowers the output ripple current thus lowering the requirement on the output capacitor...

  8. Accelerator and electrodynamics capability review

    Energy Technology Data Exchange (ETDEWEB)

    Jones, Kevin W [Los Alamos National Laboratory

    2010-01-01

    Los Alamos National Laboratory (LANL) uses capability reviews to assess the science, technology and engineering (STE) quality and institutional integration and to advise Laboratory Management on the current and future health of the STE. Capability reviews address the STE integration that LANL uses to meet mission requirements. The Capability Review Committees serve a dual role of providing assessment of the Laboratory's technical contributions and integration towards its missions and providing advice to Laboratory Management. The assessments and advice are documented in reports prepared by the Capability Review Committees that are delivered to the Director and to the Principal Associate Director for Science, Technology and Engineering (PADSTE). Laboratory Management will use this report for STE assessment and planning. LANL has defined fifteen STE capabilities. Electrodynamics and Accelerators is one of the seven STE capabilities that LANL Management (Director, PADSTE, technical Associate Directors) has identified for review in Fiscal Year (FY) 2010. Accelerators and electrodynamics at LANL comprise a blend of large-scale facilities and innovative small-scale research with a growing focus on national security applications. This review is organized into five topical areas: (1) Free Electron Lasers; (2) Linear Accelerator Science and Technology; (3) Advanced Electromagnetics; (4) Next Generation Accelerator Concepts; and (5) National Security Accelerator Applications. The focus is on innovative technology with an emphasis on applications relevant to Laboratory mission. The role of Laboratory Directed Research and Development (LDRD) in support of accelerators/electrodynamics will be discussed. The review provides an opportunity for interaction with early career staff. Program sponsors and customers will provide their input on the value of the accelerator and electrodynamics capability to the Laboratory mission.

  9. Telematics Options and Capabilities

    Energy Technology Data Exchange (ETDEWEB)

    Hodge, Cabell [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2017-09-05

    This presentation describes the data tracking and analytical capabilities of telematics devices. Federal fleet managers can use the systems to keep their drivers safe, maintain a fuel efficient fleet, ease their reporting burden, and save money. The presentation includes an example of how much these capabilities can save fleets.

  10. New Integrated Multilevel Converter for Switched Reluctance Motor Drives in Plug-in Hybrid Electric Vehicles with Flexible Energy Conversion

    DEFF Research Database (Denmark)

    Gan, Chun; Wu, Jianhua; Hu, Yihua;

    2017-01-01

    . In generator driving mode, the battery bank is employed to elevate the phase voltage for fast excitation and demagnetization. In battery driving mode, the converter is reconfigured as a four-level converter, and the capacitor is used as an additional charge capacitor to produce multilevel voltage outputs......, which enhances the torque capability. The operating modes of the proposed drive are explained and the phase current and voltage are analyzed in details. The battery charging is naturally achieved by the demagnetization current in motoring mode and by the regenerative current in braking mode. Moreover......, the battery can be charged by the external AC source or generator when the vehicle is in standstill condition. The SRM-based PHEV can operate at different speeds by coordinating power flow from the generator and battery. Simulation in MATLAB/Simulink and experiments on a three-phase 12/8 SRM confirm...

  11. 78 FR 20219 - National Financial Capability Month, 2013

    Science.gov (United States)

    2013-04-04

    ... opportunity takes more than drive and initiative--it also requires smart financial planning. During National Financial Capability Month, we recommit to empowering individuals and families with the knowledge and tools... Documents#0;#0; ] Proclamation 8951 of March 29, 2013 National Financial Capability Month, 2013 By...

  12. Driving After a Stroke

    Science.gov (United States)

    ... Inspirational Stories Stroke Heroes Among Us Driving After Stroke Updated:Jul 23,2015 Can I drive after ... more tips for daily living . Let's Talk About Stroke Fact Sheets Our stroke fact sheets cover treatments, ...

  13. Electric Vehicle - Economical driving

    DEFF Research Database (Denmark)

    Jensen, VCE, Steen V.; Schøn, Henriette

    1999-01-01

    Instruct the reader in getting most satisfaction out of an EV, especially concerning driving and loading.......Instruct the reader in getting most satisfaction out of an EV, especially concerning driving and loading....

  14. Dementia and driving

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/patientinstructions/000028.htm Dementia and driving To use the sharing features on ... please enable JavaScript. If your loved one has dementia , deciding when they can no longer drive may ...

  15. Medical restrictions to driving: the awareness of patients and doctors.

    Science.gov (United States)

    Kelly, R; Warke, T; Steele, I

    1999-09-01

    The study was set up to investigate the awareness of elderly patients and medical doctors of medical restrictions to driving. Separate questionnaires were completed by patients and doctors. All were interviewed face-to-face, without prior warning and their immediate answers were recorded. In total, 150 elderly patients from the acute elderly care wards, rehabilitation wards and day hospital, and 50 doctors (including all grades from consultant to junior house officer) were interviewed. The main outcome measures were numbers of patients currently driving and previously driving; patients' awareness of how their medical condition affected their ability to drive; doctors' spontaneous knowledge of medical conditions which restrict driving, current licensing policy, and restrictions for five specific medical conditions (epilepsy, myocardial infarction, stroke, 5-cm abdominal aortic aneurysm, and diabetes). Only 21 patients were current drivers, and six of these should not have been driving. While 103 perceived themselves eligible to drive, 46 had medical restrictions to driving. Seventeen of the 47 patients who perceived themselves not eligible to drive possibly did not have restrictions to driving. Doctors' knowledge of the current licensing policy and action to be taken if a patient was not eligible to drive was very poor. Knowledge of medical restrictions to driving was scanty, with few doctors giving the correct driving restrictions for the five specific conditions. We recommend that education of doctors regarding medical restrictions to driving should begin at an undergraduate level and be continued throughout their postgraduate career.

  16. Gear bearing drive

    Science.gov (United States)

    Weinberg, Brian (Inventor); Mavroidis, Constantinos (Inventor); Vranish, John M. (Inventor)

    2011-01-01

    A gear bearing drive provides a compact mechanism that operates as an actuator providing torque and as a joint providing support. The drive includes a gear arrangement integrating an external rotor DC motor within a sun gear. Locking surfaces maintain the components of the drive in alignment and provide support for axial loads and moments. The gear bearing drive has a variety of applications, including as a joint in robotic arms and prosthetic limbs.

  17. DrivingSense: Dangerous Driving Behavior Identification Based on Smartphone Autocalibration

    Directory of Open Access Journals (Sweden)

    Chunmei Ma

    2017-01-01

    Full Text Available Since pervasive smartphones own advanced computing capability and are equipped with various sensors, they have been used for dangerous driving behaviors detection, such as drunk driving. However, sensory data gathered by smartphones are noisy, which results in inaccurate driving behaviors estimations. Some existing works try to filter noise from sensor readings, but usually only the outlier data are filtered. The noises caused by hardware of the smartphone cannot be removed from the sensor reading. In this paper, we propose DrivingSense, a reliable dangerous driving behavior identification scheme based on smartphone autocalibration. We first theoretically analyze the impact of the sensor error on the vehicle driving behavior estimation. Then, we propose a smartphone autocalibration algorithm based on sensor noise distribution determination when a vehicle is being driven. DrivingSense leverages the corrected sensor parameters to identify three kinds of dangerous behaviors: speeding, irregular driving direction change, and abnormal speed control. We evaluate the effectiveness of our scheme under realistic environments. The results show that DrivingSense, on average, is able to detect the driving direction change event and abnormal speed control event with 93.95% precision and 90.54% recall, respectively. In addition, the speed estimation error is less than 2.1 m/s, which is an acceptable range.

  18. Capabilities for Strategic Adaptation

    DEFF Research Database (Denmark)

    Distel, Andreas Philipp

    organizational conditions, such as organizational design, support the emergence and performance of such capabilities. In detail, the dissertation consists of three self-contained research papers. The first paper is a systematic, multilevel review of the innovation literature; it reinterprets evidence from prior...... firms’ ability to absorb and leverage new knowledge. The third paper is an empirical study which conceptualizes top managers’ resource cognition as a managerial capability underlying firms’ resource adaptation; it empirically examines the performance implications of this capability and organizational...... empirical studies through the dynamic capabilities lens and develops propositions for future research. The second paper is an empirical study on the origins of firm-level absorptive capacity; it explores how organization-level antecedents, through their impact on individual-level antecedents, influence...

  19. Defence Capability Plan 2009

    Science.gov (United States)

    2009-01-01

    financed lease , or elements of both. Background Initially, an improved rotary wing training capability was to be provided under two projects – Phase 7A...Destroyer (AWD), Super Hornet and New Air Combat Capability (NACC). Through-life Support The Commonwealth seeks a ‘ turnkey ’ service providing aerial...combination: > Commercial- and/or Military-off-the-Shelf; or > open tender for ADF ownership or lease . Through-life Support Depending on the procurement (ADF

  20. Capabilities for strategic flexibility:a cognitive content framework

    OpenAIRE

    Combe, Ian; Greenley, Gordon E.

    2004-01-01

    Different forms of strategic flexibility allow for reactive adaptation to different changing environments and the proactive driving of change. It is therefore becoming increasingly important for decision makers to not only possess marketing capabilities, but also the capabilities for strategic flexibility in its various forms. However, our knowledge of the relationships between decision makers’ different ways of thinking and their capabilities for strategic flexibility is limited. This limita...

  1. Simple Driving Techniques

    DEFF Research Database (Denmark)

    Rosendahl, Mads

    2002-01-01

    -like language. Our aim is to extract a simple notion of driving and show that even in this tamed form it has much of the power of more general notions of driving. Our driving technique may be used to simplify functional programs which use function composition and will often be able to remove intermediate data......Driving was introduced as a program transformation technique by Valentin Turchin in some papers around 1980. It was intended for the programming language REFAL and used in metasystem transitions based on super compilation. In this paper we present one version of driving for a more conventional lisp...

  2. High performance AC drives

    CERN Document Server

    Ahmad, Mukhtar

    2010-01-01

    This book presents a comprehensive view of high performance ac drives. It may be considered as both a text book for graduate students and as an up-to-date monograph. It may also be used by R & D professionals involved in the improvement of performance of drives in the industries. The book will also be beneficial to the researchers pursuing work on multiphase drives as well as sensorless and direct torque control of electric drives since up-to date references in these topics are provided. It will also provide few examples of modeling, analysis and control of electric drives using MATLAB/SIMULIN

  3. Structural Capability of an Organization toward Innovation Capability

    DEFF Research Database (Denmark)

    Nielsen, Susanne Balslev; Momeni, Mostafa

    2016-01-01

    competitive advantage in the organizations is the innovation capability. The innovation capability is associated with other organizational capabilities, and many organizations have focused on the need to identify innovation capabilities.This research focuses on recognition of the structural aspect...... of innovation capability and proposes a conceptual framework based on a Qualitative Meta Synthesis of academic literature on organizations innovation capability. This is proposed for the development of the concept of innovation capability in the organizations and this paper includes an expert based validation...... Capability and Structural Capability. Also, it offers the most important components and indices which directly influence and are related to the structural capability of innovation capability....

  4. Ion drive - A step toward 'Star Trek'

    Science.gov (United States)

    Atkins, K. L.; Terwilliger, C.

    1976-01-01

    The design of a solar-powered electric propulsion system is seen as the first step in the ultimate development of an ion drive system which might incorporate many features of a spacecraft propulsion system described in a science fiction novel written by Anderson (1970). The considered ion propulsion systems would make it possible to augment significantly the operational capabilities of space transportation systems utilizing the Shuttle orbiter in combination with a solid-propellant interim upper stage. The use of the ion drive in a number of applications is discussed, giving attention to the resulting enhancement of national space capabilities, the role of the ion drive in the space transportation system, the development and the operation of a manned space station, satellite positioning and service, the elimination of space debris objects, the study of Halley's comet, interplanetary or lunar shuttle services, and space missions involving the outer planets.

  5. A comprehensive estimation method for enterprise capability

    Directory of Open Access Journals (Sweden)

    Tetiana Kuzhda

    2015-11-01

    Full Text Available In today’s highly competitive business world, the need for efficient enterprise capability management is greater than ever. As more enterprises begin to compete on a global scale, the effective use of enterprise capability will become imperative for them to improve their business activities. The definition of socio-economic capability of the enterprise has been given and the main components of enterprise capability have been pointed out. The comprehensive method to estimate enterprise capability that takes into account both social and economic components has been offered. The methodical approach concerning integrated estimation of the enterprise capability has been developed. Novelty deals with the inclusion of summary measure of the social component of enterprise capability to define the integrated index of enterprise capability. The practical significance of methodological approach is that the method allows assessing the enterprise capability comprehensively through combining two kinds of estimates – social and economic and converts them into a single integrated indicator. It provides a comprehensive approach to socio-economic estimation of enterprise capability, sets a formal basis for making decisions and helps allocate enterprise resources reasonably. Practical implementation of this method will affect the current condition and trends of the enterprise, help to make forecasts and plans for its development and capability efficient use.

  6. Influence of DSP controller on performance of a permanent magnet brushless AC drive in flux-weakening mode

    Institute of Scientific and Technical Information of China (English)

    ZHU Z.Q.; SHI Y.F.; HOWE D.

    2005-01-01

    The flux-weakening performance of a permanent magnet brushless AC drive was investigated using both floating-point and fixed-point DSP controllers. A significant current oscillation was observed when the drive was operated at high-speed in the flux-weakening mode with the fixed-point DSP. The investigation showed that this was due to the on-line compensation of the winding resistance voltage drop and quantisation errors associated with the fixed-point architecture of the DSP. A simple look-up table scheme is proposed to eliminate the oscillation and to achieve extended flux-weakening capability.

  7. Rapid Capability Fielding Toolbox Study

    Science.gov (United States)

    2010-03-01

    should  inventory  and  leverage  the  substantial  capabilities  currently existing across  the  department  in M&S  (game and virtual environment...Northwestern University, and  Samsung .   One example project  that  included  significant  use of UCD  tools was  the development of  the Chicago Bus Rapid...Establish C2E training and career development programs for DoD engineers.  Recommendation:   Inventory  DoD Laboratory Capabilities  The DoD  should

  8. Dielectric Wakefield Accelerator to drive the future FEL Light Source.

    Energy Technology Data Exchange (ETDEWEB)

    Jing, C.; Power, J.; Zholents, A. (Accelerator Systems Division (APS)); ( HEP); (LLC)

    2011-04-20

    X-ray free-electron lasers (FELs) are expensive instruments and a large part of the cost of the entire facility is driven by the accelerator. Using a high-energy gain dielectric wake-field accelerator (DWA) instead of the conventional accelerator may provide a significant cost saving and reduction of the facility size. In this article, we investigate using a collinear dielectric wakefield accelerator to provide a high repetition rate, high current, high energy beam to drive a future FEL x-ray light source. As an initial case study, a {approx}100 MV/m loaded gradient, 850 GHz quartz dielectric based 2-stage, wakefield accelerator is proposed to generate a main electron beam of 8 GeV, 50 pC/bunch, {approx}1.2 kA of peak current, 10 x 10 kHz (10 beamlines) in just 100 meters with the fill factor and beam loading considered. This scheme provides 10 parallel main beams with one 100 kHz drive beam. A drive-to-main beam efficiency {approx}38.5% can be achieved with an advanced transformer ratio enhancement technique. rf power dissipation in the structure is only 5 W/cm{sup 2} in the high repetition rate, high gradient operation mode, which is in the range of advanced water cooling capability. Details of study presented in the article include the overall layout, the transform ratio enhancement scheme used to increase the drive to main beam efficiency, main wakefield linac design, cooling of the structure, etc.

  9. Kokkos? Task DAG Capabilities.

    Energy Technology Data Exchange (ETDEWEB)

    Edwards, Harold C.; Ibanez, Daniel Alejandro

    2017-09-01

    This report documents the ASC/ATDM Kokkos deliverable "Production Portable Dy- namic Task DAG Capability." This capability enables applications to create and execute a dynamic task DAG ; a collection of heterogeneous computational tasks with a directed acyclic graph (DAG) of "execute after" dependencies where tasks and their dependencies are dynamically created and destroyed as tasks execute. The Kokkos task scheduler executes the dynamic task DAG on the target execution resource; e.g. a multicore CPU, a manycore CPU such as Intel's Knights Landing (KNL), or an NVIDIA GPU. Several major technical challenges had to be addressed during development of Kokkos' Task DAG capability: (1) portability to a GPU with it's simplified hardware and micro- runtime, (2) thread-scalable memory allocation and deallocation from a bounded pool of memory, (3) thread-scalable scheduler for dynamic task DAG, (4) usability by applications.

  10. Campus Capability Plan

    Energy Technology Data Exchange (ETDEWEB)

    Adams, C. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Arsenlis, T. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Bailey, A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Bergman, M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Brase, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Brenner, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Camara, L. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Carlton, H. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Cheng, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Chrzanowski, P. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Colson, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); East, D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Farrell, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Ferranti, L. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Gursahani, A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Hansen, R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Helms, L. L. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Hernandez, M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Jeffries, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Larson, D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Lu, K. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); McNabb, D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Mercer, M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Skeate, M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Sueksdorf, M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Zucca, B. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Le, D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Ancria, R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Scott, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Leininger, L. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Gagliardi, F. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Gash, A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Bronson, M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Chung, B. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Hobson, B. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Meeker, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Sanchez, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Zagar, M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Quivey, B. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Sommer, S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Atherton, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-06-06

    Lawrence Livermore National Laboratory Campus Capability Plan for 2018-2028. Lawrence Livermore National Laboratory (LLNL) is one of three national laboratories that are part of the National Nuclear Security Administration. LLNL provides critical expertise to strengthen U.S. security through development and application of world-class science and technology that: Ensures the safety, reliability, and performance of the U.S. nuclear weapons stockpile; Promotes international nuclear safety and nonproliferation; Reduces global danger from weapons of mass destruction; Supports U.S. leadership in science and technology. Essential to the execution and continued advancement of these mission areas are responsive infrastructure capabilities. This report showcases each LLNL capability area and describes the mission, science, and technology efforts enabled by LLNL infrastructure, as well as future infrastructure plans.

  11. Management Innovation Capabilities

    DEFF Research Database (Denmark)

    Harder, Mie

    Management innovation is the implementation of a new management practice, process, technique or structure that significantly alters the way the work of management is performed. This paper presents a typology categorizing management innovation along two dimensions; radicalness and complexity. Then......, the paper introduces the concept of management innovation capabilities which refers to the ability of a firm to purposefully create, extend and modify its managerial resource base to address rapidly changing environments. Drawing upon behavioral theory of the firm and the dynamic capabilities framework......, the paper proposes a model of the foundations of management innovation. Propositions and implications for future research are discussed....

  12. Sandia QIS Capabilities.

    Energy Technology Data Exchange (ETDEWEB)

    Muller, Richard P. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-07-01

    Sandia National Laboratories has developed a broad set of capabilities in quantum information science (QIS), including elements of quantum computing, quantum communications, and quantum sensing. The Sandia QIS program is built atop unique DOE investments at the laboratories, including the MESA microelectronics fabrication facility, the Center for Integrated Nanotechnologies (CINT) facilities (joint with LANL), the Ion Beam Laboratory, and ASC High Performance Computing (HPC) facilities. Sandia has invested $75 M of LDRD funding over 12 years to develop unique, differentiating capabilities that leverage these DOE infrastructure investments.

  13. Capability Handbook- offline metrology

    DEFF Research Database (Denmark)

    Islam, Aminul; Marhöfer, David Maximilian; Tosello, Guido

    This offline metrological capability handbook has been made in relation to HiMicro Task 3.3. The purpose of this document is to assess the metrological capability of the HiMicro partners and to gather the information of all available metrological instruments in the one single document. It provides...... a quick overview of what is possible today by the state of the art, what the HiMicro consortium can do and what metrological requirements we have concerning the HiMicro industrial demonstrators....

  14. Opportunities and Cooperation Drive Prosperity

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    The old industrial base is lying in Northeast China. Although boasting many advantages such as talents, resources, transportation, environment, the region still have many disadvantages that needs opening up and reform. Revitalizing the Northeast region is an important task for China to built well-off society in an all-round way in the new century. It is also a big strategy made after developing costal region and western region by Chinese leaders according to current situation, which is a driving force

  15. Diplopia and driving: a problematic issue.

    Science.gov (United States)

    Righi, Stefano; Boffano, Paolo; Guglielmi, Valeria; Rossi, Paolo; Martorina, Massimo

    2014-10-01

    The aim of this article was to review the literature regarding diplopia and driving license and to review the West European legislations about this topic, in order to obtain appropriate indications for hospitals specialists and patients. A systematic review of articles published about diplopia and driving was performed. In addition a review of West European national legislations about driving license regulations for medical illnesses was performed, in addition to the European Union Directive on driving licenses. In the literature, the presence of diplopia has not been considered a reliable predictor of the safety of driving behavior, or it has not appeared to be a contraindication for driving according to some authors who were unable to demonstrate significant differences on driving simulator performance between subjects with chronic stable diplopia and control subjects. Nevertheless, in all western European legislations, acute diplopia constitutes an important limitation for driving, thus making the knowledge of current regulations fundamental for specialists involved in managing patients with diplopia. Ophthalmologists and maxillofacial/head and neck surgeons, may advise patients before hospital discharge about current legislations in their respective countries.

  16. STRATEGIC AIRLIFT CAPABILITY: FROM THEORY TO PRACTICE

    Directory of Open Access Journals (Sweden)

    Cezar VASILESCU

    2011-01-01

    Full Text Available Strategic airlift remains a critical supporting capability that should be achieved, maintained and improved. This capability ensures the ability to deploy and sustain military forces across possible distant battlefields. The paper analyses the growing strategic airlift capabilities gap between operational needs and current realities, and underlines the need for an enhanced strategic airlift capability to meet current and future NATO alliance needs. By analyzing requirements against the existing/potential solutions, this paper further ponders over options like the organic national capability, partnerships such as the Strategic Airlift Consortium (SAC or leasing aircraft through a venture such as the Strategic Airlift Interim Solution (SALIS. The paper also evaluates the feasibility of applying these solutions to European Union airlift needs.

  17. Warp Drive - From Imagination to Reality

    Science.gov (United States)

    Gardiner, J.

    The realisation of warp drive is far beyond current science and technology; nevertheless, setting out a timetable for the realisation of warp drive is instructive as this will set expectations for the progress of future research. It is proposed that a time scale for the realisation of warp drive can be estimated by historical analogy with the development of manned space travel to the Moon, using conventional project estimation techniques. A timeline for space travel to the Moon begins with Cyrano de Bergerac's Voyage dans la Lune in 1657 and culminates with the Apollo 11 Moon landing in 1969, a little over 300 years later. A similar timeline for warp drive begins with John W. Campbell's novel Islands of Space in 1930. Fictional conjecture on the warp drive has given way to serious scientific speculation following publication of Alcubierre's seminal warp drive paper in 1994. It is concluded that the realisation of warp drive might be achieved around the year 2180. A projected timetable for the realisation of warp drive through phases of conjecture , speculation , science , technology and application suggests that the warp drive proposal should enter the science phase around the year 2030.

  18. Lectures on magnetohydrodynamical drives

    Science.gov (United States)

    Loigom, Villem

    The paper deals with nonconventional types of electrical machines and drives - magnetohydrodynamical (MHD) machines and drives. In cardinal it is based on the research conducted with participation of the author in Tallinn Technical University at the Institute of Electrical Drives and Power Electronics, where the use of magnetohydrodynamical motors and drives in the metallurgical and casting industries have been studied for a long time. Major research interests include the qualities and applications of the induction MHD-drives for set in the motion (pumping, turning, dosing, mixing, etc.) non-ferrous molten metals like Al, Mg, Sn, Pb, Na, K, and their alloys. The first part of the paper describes induction MHD motors and their electrohydraulical qualities. In the second part energy conversion problems are described. Also, on the basis of the analogy between electromechanical and electrohydraulical phenomenas, static and dynamic qualities of MHD drives with induction MHD machines are discussed.

  19. Capabilities Composition (Briefing Charts)

    Science.gov (United States)

    2009-04-22

    and support , , processes (including ITIL v3) • Understanding of Governance is still evolving Engineering Acquisition and Operational Governance...L – Logistics • NC – Net-Centric • CPM – Capability Portfolio Management • ITIL v3 – Information Technology • ONR – Office of Naval Research

  20. Building server capabilities

    DEFF Research Database (Denmark)

    Adeyemi, Oluseyi

    -only”, exporting parts and components back to headquarter for sales in the home country. In the course of time, the role of offshore subsidiaries in a company’s operations network tends to change and, with that, the capabilities, of the subsidiaries. Focusing on Danish subsidiaries in China, the objective...

  1. Building Server Capabilities

    DEFF Research Database (Denmark)

    Adeyemi, Oluseyi

    2013-01-01

    -only”, exporting parts and components back to headquarter for sales in the home country. In the course of time, the role of offshore subsidiaries in a company’s operations network tends to change and, with that, the capabilities, of the subsidiaries. Focusing on Danish subsidiaries in China, the objective...

  2. Capabilities Report 2012

    Science.gov (United States)

    2012-01-01

    74 Biosurveillance - Rapid Identification of Unknown Microorganisms...RSI is dedicated to the effort and capabilities of enabling biosurveillance through coordinated and integrated national and international systems...natural, accidental, or deliberate in nature. These initiatives include: biosurveillance , outbreak recognition and avoidance, pathogen characterization

  3. Capabilities for Intercultural Dialogue

    Science.gov (United States)

    Crosbie, Veronica

    2014-01-01

    The capabilities approach offers a valuable analytical lens for exploring the challenge and complexity of intercultural dialogue in contemporary settings. The central tenets of the approach, developed by Amartya Sen and Martha Nussbaum, involve a set of humanistic goals including the recognition that development is a process whereby people's…

  4. Metrology Measurement Capabilities

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Glen E. Gronniger

    2007-10-02

    This document contains descriptions of Federal Manufacturing & Technologies (FM&T) Metrology capabilities, traceability flow charts, and the measurement uncertainty of each measurement capability. Metrology provides NIST traceable precision measurements or equipment calibration for a wide variety of parameters, ranges, and state-of-the-art uncertainties. Metrology laboratories conform to the requirements of the Department of Energy Development and Production Manual Chapter 13.2, ANSI/ISO/IEC ANSI/ISO/IEC 17025:2005, and ANSI/NCSL Z540-1. FM&T Metrology laboratories are accredited by NVLAP for the parameters, ranges, and uncertainties listed in the specific scope of accreditation under NVLAP Lab code 200108-0. See the Internet at http://ts.nist.gov/Standards/scopes/2001080.pdf. These parameters are summarized. The Honeywell Federal Manufacturing & Technologies (FM&T) Metrology Department has developed measurement technology and calibration capability in four major fields of measurement: (1) Mechanical; (2) Environmental, Gas, Liquid; (3) Electrical (DC, AC, RF/Microwave); and (4) Optical and Radiation. Metrology Engineering provides the expertise to develop measurement capabilities for virtually any type of measurement in the fields listed above. A strong audit function has been developed to provide a means to evaluate the calibration programs of our suppliers and internal calibration organizations. Evaluation includes measurement audits and technical surveys.

  5. ISOPHOT - Capabilities and performance

    DEFF Research Database (Denmark)

    Lemke, D.; Klaas, U.; Abolins, J.

    1996-01-01

    ISOPHOT covers the largest wavelength range on ISO from 2.5 to 240 mu m. Its scientific capabilities include multi filter and multi-aperture photometry, polarimetry, imaging and spectrophotometry. All modes can optionally include a focal plane chopper. The backbone of the photometric calibration...

  6. Capabilities for Intercultural Dialogue

    Science.gov (United States)

    Crosbie, Veronica

    2014-01-01

    The capabilities approach offers a valuable analytical lens for exploring the challenge and complexity of intercultural dialogue in contemporary settings. The central tenets of the approach, developed by Amartya Sen and Martha Nussbaum, involve a set of humanistic goals including the recognition that development is a process whereby people's…

  7. The Capability Approach

    NARCIS (Netherlands)

    I.A.M. Robeyns (Ingrid)

    2011-01-01

    textabstract In its most general description, the capability approach is a flexible and multi-purpose normative framework, rather than a precise theory of well-being, freedom or justice. At its core are two normative claims: first, the claim that the freedom to achieve well-being is of primary mora

  8. Practitioner Perspectives on Foundational Capabilities

    Science.gov (United States)

    Leider, Jonathon P.; Juliano, Chrissie; Castrucci, Brian C.; Beitsch, Leslie M.; Dilley, Abby; Nelson, Rachel; Kaiman, Sherry; Sprague, James B.

    2015-01-01

    Context: National efforts are underway to classify a minimum set of public health services that all jurisdictions throughout the United States should provide regardless of location. Such a set of basic programs would be supported by crosscutting services, known as the “foundational capabilities” (FCs). These FCs are assessment services, preparedness and disaster response, policy development, communications, community partnership, and organizational support activities. Objective: To ascertain familiarity with the term and concept of FCs and gather related perspectives from state and local public health practitioners. Design: In fall 2013, we interviewed 50 leaders from state and local health departments. We asked about familiarity with the term “foundational capabilities,” as well as the broader concept of FCs. We attempted to triangulate the utility of the FC concept by asking respondents about priority programs and services, about perceived unique contributions made by public health, and about prevalence and funding for the FCs. Setting: Telephone-based interviews. Participants: Fifty leaders of state and local health departments. Main Outcome Measures: Practitioner familiarity with and perspectives on the FCs, information about current funding streams for public health, and the likelihood of creating nationwide FCs that would be recognized and accepted by all jurisdictions. Results: Slightly more than half of the leaders interviewed said that they were familiar with the concept of FCs. In most cases, health departments had all of the capabilities to some degree, although operationalization varied. Few indicated that current funding levels were sufficient to support implementing a minimum level of FCs nationally. Conclusions: Respondents were not able to articulate the current or optimal levels of services for the various capabilities, nor the costs associated with them. Further research is needed to understand the role of FCs as part of the foundational

  9. Capitalizing on capabilities.

    Science.gov (United States)

    Ulrich, Dave; Smallwood, Norm

    2004-06-01

    By making the most of organizational capabilities--employees' collective skills and fields of expertise--you can dramatically improve your company's market value. Although there is no magic list of proficiencies that every organization needs in order to succeed, the authors identify 11 intangible assets that well-managed companies tend to have: talent, speed, shared mind-set and coherent brand identity, accountability, collaboration, learning, leadership, customer connectivity, strategic unity, innovation, and efficiency. Such companies typically excel in only three of these capabilities while maintaining industry parity in the other areas. Organizations that fall below the norm in any of the 11 are likely candidates for dysfunction and competitive disadvantage. So you can determine how your company fares in these categories (or others, if the generic list doesn't suit your needs), the authors explain how to conduct a "capabilities audit," describing in particular the experiences and findings of two companies that recently performed such audits. In addition to highlighting which intangible assets are most important given the organization's history and strategy, this exercise will gauge how well your company delivers on its capabilities and will guide you in developing an action plan for improvement. A capabilities audit can work for an entire organization, a business unit, or a region--indeed, for any part of a company that has a strategy to generate financial or customer-related results. It enables executives to assess overall company strengths and weaknesses, senior leaders to define strategy, midlevel managers to execute strategy, and frontline leaders to achieve tactical results. In short, it helps turn intangible assets into concrete strengths.

  10. The influence of music on mental effort and driving performance

    NARCIS (Netherlands)

    Ünal, Ayca Berfu; Steg, Linda; Epstude, Kai

    The current research examined the influence of loud music on driving performance, and whether mental effort mediated this effect. Participants (N = 69) drove in a driving simulator either with or without listening to music. In order to test whether music would have similar effects on driving

  11. The influence of music on mental effort and driving performance

    NARCIS (Netherlands)

    Ünal, Ayca Berfu; Steg, Linda; Epstude, Kai

    2012-01-01

    The current research examined the influence of loud music on driving performance, and whether mental effort mediated this effect. Participants (N = 69) drove in a driving simulator either with or without listening to music. In order to test whether music would have similar effects on driving perform

  12. Foreign driving licences in Switzerland

    CERN Multimedia

    DG Unit

    2009-01-01

    1. Persons residing in Switzerland 1.1 Holders of a B, C, D, E or P-type "carte de légitimation" For holders of a B, C, D, E or P-type "carte de légitimation" issued by the Swiss Federal Department for Foreign Affairs (DFAE), current non-Swiss national driving licences are valid in Switzerland. If they so wish, holders of such driving licences may apply to the relevant road licensing authority in the canton where they live (Service des Automobiles et de la Navigation; for Geneva call + 41 22 388 30 30, website http://www.geneve.ch/san; for Vaud call + 41 21 316 82 10, website http://www.san.vd.ch/index.html) to exchange their driving licence for an equivalent Swiss licence (they must pass a test if they are not citizens of countries with which Switzerland has concluded an agreement on this matter, e.g. Member States of the European Union, the United States and Japan). However, such an exchange is not possible if the driving licence was issued in a foreign country during a...

  13. FOREIGN DRIVING LICENCES IN SWITZERLAND

    CERN Multimedia

    Relatiopns with the Host States Service

    2001-01-01

    1. PERSONS RESIDING IN SWITZERLAND 1.1 Holders of a B, C, D or E-type carte de légitimation For holders of B, C, D or E-type cartes de légitimation issued by the Swiss Federal Department for Foreign Affairs (Département fédéral suisse des Affaires étrangères, hereinafter called DFAE), current non-Swiss national driving licences are valid in Switzerland. Should they so wish, holders of such driving licences may apply to the relevant roads authority in the canton where they live (Service des Automobiles et de la Navigation ; for Geneva call 022/343 02 00, website: http://www.geneve.ch/san/welcome.html, for Vaud call 021/316 82 10, website: http://www.dse.vd.ch/auto/index.html) in order to exchange their driving licence for an equivalent Swiss licence. However, exchanges are not permitted if the driving licence was issued in a foreign country during a stay there of less than six months' duration while the person concerned was officially...

  14. Evaluation of semiconductor devices for Electric and Hybrid Vehicle (EHV) ac-drive applications, volume 1

    Science.gov (United States)

    Lee, F. C.; Chen, D. Y.; Jovanovic, M.; Hopkins, D. C.

    1985-01-01

    The results of evaluation of power semiconductor devices for electric hybrid vehicle ac drive applications are summarized. Three types of power devices are evaluated in the effort: high power bipolar or Darlington transistors, power MOSFETs, and asymmetric silicon control rectifiers (ASCR). The Bipolar transistors, including discrete device and Darlington devices, range from 100 A to 400 A and from 400 V to 900 V. These devices are currently used as key switching elements inverters for ac motor drive applications. Power MOSFETs, on the other hand, are much smaller in current rating. For the 400 V device, the current rating is limited to 25 A. For the main drive of an electric vehicle, device paralleling is normally needed to achieve practical power level. For other electric vehicle (EV) related applications such as battery charger circuit, however, MOSFET is advantageous to other devices because of drive circuit simplicity and high frequency capability. Asymmetrical SCR is basically a SCR device and needs commutation circuit for turn off. However, the device poses several advantages, i.e., low conduction drop and low cost.

  15. Concerning RNA-guided gene drives for the alteration of wild populations

    Science.gov (United States)

    Esvelt, Kevin M; Smidler, Andrea L; Catteruccia, Flaminia; Church, George M

    2014-01-01

    Gene drives may be capable of addressing ecological problems by altering entire populations of wild organisms, but their use has remained largely theoretical due to technical constraints. Here we consider the potential for RNA-guided gene drives based on the CRISPR nuclease Cas9 to serve as a general method for spreading altered traits through wild populations over many generations. We detail likely capabilities, discuss limitations, and provide novel precautionary strategies to control the spread of gene drives and reverse genomic changes. The ability to edit populations of sexual species would offer substantial benefits to humanity and the environment. For example, RNA-guided gene drives could potentially prevent the spread of disease, support agriculture by reversing pesticide and herbicide resistance in insects and weeds, and control damaging invasive species. However, the possibility of unwanted ecological effects and near-certainty of spread across political borders demand careful assessment of each potential application. We call for thoughtful, inclusive, and well-informed public discussions to explore the responsible use of this currently theoretical technology. DOI: http://dx.doi.org/10.7554/eLife.03401.001 PMID:25035423

  16. Validation of the ultrasonic and Eddy current techniques to inspect the accommodation of the elements of (CRDH) control rod drive; Validacion de las tecnicas de ultrasonidos y corrientes inducidas para inspeccionar los alojamientos

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, A.; Gomez, P.; Sanchez, J.; Resa, P.

    2013-07-01

    Tecnatom development in the past with ultrasonic inspection procedures to examine vessels BWR of several Central nuclear (CRDH) control rod drive elements, accommodations. In each case, inspection techniques have relied on both the volume of required test postulated defects. Also, taking into account the possible access to the component, developed mechanical equipments of different characteristics.

  17. Exploration Medical Capability - Technology Watch

    Science.gov (United States)

    Krihak, Michael; Watkins, Sharmila; Barr, Yael; Barsten, Kristina; Fung, Paul; Baumann, David

    2011-01-01

    The objectives of the Technology Watch process are to identify emerging, high-impact technologies that augment current ExMC development efforts, and to work with academia, industry, and other government agencies to accelerate the development of medical care and research capabilities for the mitigation of potential health issues that could occur during space exploration missions. The establishment of collaborations with these entities is beneficial to technology development, assessment and/or insertion. Such collaborations also further NASA s goal to provide a safe and healthy environment for human exploration. The Tech Watch project addresses requirements and capabilities identified by knowledge and technology gaps that are derived from a discrete set of medical conditions that are most likely to occur on exploration missions. These gaps are addressed through technology readiness level assessments, market surveys, collaborations and distributed innovation opportunities. Ultimately, these gaps need to be closed with respect to exploration missions, and may be achieved through technology development projects. Information management is a key aspect to this process where Tech Watch related meetings, research articles, collaborations and partnerships are tracked by the HRP s Exploration Medical Capabilities (ExMC) Element. In 2011, ExMC will be introducing the Tech Watch external website and evidence wiki that will provide access to ExMC technology and knowledge gaps, technology needs and requirements documents.

  18. Metrology Measurement Capabilities

    Energy Technology Data Exchange (ETDEWEB)

    Barnes, L.M.

    2000-03-23

    This document contains descriptions of Federal Manufacturing and Technologies (FM and T) Metrology capabilities, traceability flow charts, and the measurement uncertainty of each measurement capability. Metrology provides NIST traceable precision measurements or equipment calibration for a wide variety of parameters, ranges, and state-of-the-art uncertainties in laboratories that conform to the requirements of the Department of Energy Development and Production Manual Chapter 8.4, and ANSI/NCSL Z540-1 (equivalent to ISO Guide 25). FM and T Metrology laboratories are accredited by NVLAP for the parameters, ranges, and uncertainties listed in the specific scope of accreditation under NVLAP Lab code 200108-0. These parameters are summarized.

  19. Metrology Measurement Capabilities

    Energy Technology Data Exchange (ETDEWEB)

    Barnes, L.M.

    2003-11-12

    This document contains descriptions of Federal Manufacturing & Technologies (FM&T) Metrology capabilities, traceability flow charts, and the measurement uncertainty of each measurement capability. Metrology provides NIST traceable precision measurements or equipment calibration for a wide variety of parameters, ranges, and state-of-the-art uncertainties. Metrology laboratories conform to the requirements of the Department of Energy Development and Production Manual Chapter 8.4, ANSI/ISO/IEC ANSI/ISO/IEC 17025:2000, and ANSI/NCSL Z540-1 (equivalent to ISO Guide 25). FM&T Metrology laboratories are accredited by NVLAP for the parameters, ranges, and uncertainties listed in the specific scope of accreditation under NVLAP Lab code 200108-0. See the Internet at http://ts.nist.gov/ts/htdocs/210/214/scopes/2001080.pdf. These parameters are summarized in the table at the bottom of this introduction.

  20. Capabilities and Special Needs

    DEFF Research Database (Denmark)

    Kjeldsen, Christian Christrup

    thesis deals with a new Danish innovative policy (Act. no. 564 of 2007), a social work and educational intervention for mentally challenged Young people and other young people with special needs, the so-called individually arranged youth education (STU). The investigated area has lately been taken......The author, Christian Christrup Kjeldsen, presents a comprehensive capability-oriented study of high excellence. For this work he has recieved the doctor titel Dr.phil (Doktor der Philosophie) from Bielefeld University, Germany 2013 with the highest possible grade "ausgezeichnet". The doctoral...... into international consideration in relation to the implementation of the UN convention on the rights of persons with disabilities. As for the theoretical basis, the research makes use of the sociological open-ended and relational concepts of Pierre Bourdieu and the normative yardstick of the Capability Approach...

  1. Capabilities and Special Needs

    DEFF Research Database (Denmark)

    Kjeldsen, Christian Christrup

    The author, Christian Christrup Kjeldsen, presents a comprehensive capability-oriented study of high excellence. For this work he has recieved the doctor titel Dr.phil (Doktor der Philosophie) from Bielefeld University, Germany 2013 with the highest possible grade "ausgezeichnet". The doctoral...... thesis deals with a new Danish innovative policy (Act. no. 564 of 2007), a social work and educational intervention for mentally challenged Young people and other young people with special needs, the so-called individually arranged youth education (STU). The investigated area has lately been taken...... into international consideration in relation to the implementation of the UN convention on the rights of persons with disabilities. As for the theoretical basis, the research makes use of the sociological open-ended and relational concepts of Pierre Bourdieu and the normative yardstick of the Capability Approach...

  2. A Review of Intelligent Driving Style Analysis Systems and Related Artificial Intelligence Algorithms.

    Science.gov (United States)

    Meiring, Gys Albertus Marthinus; Myburgh, Hermanus Carel

    2015-12-04

    In this paper the various driving style analysis solutions are investigated. An in-depth investigation is performed to identify the relevant machine learning and artificial intelligence algorithms utilised in current driver behaviour and driving style analysis systems. This review therefore serves as a trove of information, and will inform the specialist and the student regarding the current state of the art in driver style analysis systems, the application of these systems and the underlying artificial intelligence algorithms applied to these applications. The aim of the investigation is to evaluate the possibilities for unique driver identification utilizing the approaches identified in other driver behaviour studies. It was found that Fuzzy Logic inference systems, Hidden Markov Models and Support Vector Machines consist of promising capabilities to address unique driver identification algorithms if model complexity can be reduced.

  3. Joint Forces Capabilities

    Science.gov (United States)

    2007-11-02

    for countering the proliferation of weapons of mass destruction (WMD) in space. The Space Operations Center ( SPOC ), USSPACECOM is the single point...of contact for assessing space capabilities. Combatant commanders, subordinate JFCs, and Services can access this information from the SPOC via the...special operations forces SPOC Space Operations Center SSBN fleet ballistic missile submarine SST space support team UJTL Universal Joint Task List UN

  4. Capabilities for innovation

    DEFF Research Database (Denmark)

    Nielsen, Peter; Nielsen, René Nesgaard; Bamberger, Simon Grandjean

    2012-01-01

    is a survey that collected information from 601 firms belonging to the private urban sector in Denmark. The survey was carried out in late 2010. Keywords: dynamic capabilities/innovation/globalization/employee/employer cooperation/Nordic model Acknowledgment: The GOPA study was financed by grant 20080053113....../12-2008-09 from the Foundation for Research of Work Environment, Denmark. The funders played no part in the conduct or reporting of the research....

  5. Piezoelectric drive circuit

    Science.gov (United States)

    Treu, Jr., Charles A.

    1999-08-31

    A piezoelectric motor drive circuit is provided which utilizes the piezoelectric elements as oscillators and a Meacham half-bridge approach to develop feedback from the motor ground circuit to produce a signal to drive amplifiers to power the motor. The circuit automatically compensates for shifts in harmonic frequency of the piezoelectric elements due to pressure and temperature changes.

  6. Fundamentals of electrical drives

    CERN Document Server

    Veltman, André; De Doncker, Rik W

    2007-01-01

    Provides a comprehensive introduction to various aspects of electrical drive systems. This volume provides a presentation of dynamic generic models that cover all major electrical machine types and modulation/control components of a drive as well as dynamic and steady state analysis of transformers and electrical machines.

  7. Electric vehicles: Driving range

    Science.gov (United States)

    Kempton, Willett

    2016-09-01

    For uptake of electric vehicles to increase, consumers' driving-range needs must be fulfilled. Analysis of the driving patterns of personal vehicles in the US now shows that today's electric vehicles can meet all travel needs on almost 90% of days from a single overnight charge.

  8. Recognizing driving in haste

    NARCIS (Netherlands)

    Rendón-Vélez, E.

    2014-01-01

    One can often hear people discussing the reasons why a road accident has happened: “She had to pick up her kids in the school before four o’clock and she was driving in haste and careless”, “He was stressed, he wanted to reach the beginning of the football match, tried to drive faster and didn't app

  9. Drive Around the World

    Institute of Scientific and Technical Information of China (English)

    Yang Wei

    2008-01-01

    @@ "It's so cool that I can drive on my own,and my own car,"Cao Gang,WOrking for a private company in Changsha,capital city of Hunan Province,mid-south China,said in excitement when he newly bought Ben Ben,a Chinese local auto brand of Chang'an,with his freshly-passed driving license.

  10. Recognizing driving in haste

    NARCIS (Netherlands)

    Rendón-Vélez, E.

    2014-01-01

    One can often hear people discussing the reasons why a road accident has happened: “She had to pick up her kids in the school before four o’clock and she was driving in haste and careless”, “He was stressed, he wanted to reach the beginning of the football match, tried to drive faster and didn't app

  11. Electric Vehicle - Economical driving

    DEFF Research Database (Denmark)

    Jensen, VCE, Steen V.; Schøn, Henriette

    1999-01-01

    How do you reduce the energy-wast when driving and loading EV's - or rather: How do I get more km/l out of an EV......How do you reduce the energy-wast when driving and loading EV's - or rather: How do I get more km/l out of an EV...

  12. Recognizing driving in haste

    NARCIS (Netherlands)

    Rendón-Vélez, E.

    2014-01-01

    One can often hear people discussing the reasons why a road accident has happened: “She had to pick up her kids in the school before four o’clock and she was driving in haste and careless”, “He was stressed, he wanted to reach the beginning of the football match, tried to drive faster and didn't

  13. Automated Driving System Architecture to Ensure Safe Delegation of Driving Authority

    Science.gov (United States)

    YUN, Sunkil; NISHIMURA, Hidekazu

    2016-09-01

    In this paper, the architecture of an automated driving system (ADS) is proposed to ensure safe delegation of driving authority between the ADS and a driver. Limitations of the ADS functions may activate delegation of driving authority to a driver. However, it leads to severe consequences in emergency situations where a driver may be drowsy or distracted. To address these issues, first, the concept model for the ADS in the situation for delegation of driving authority is described taking the driver's behaviour and state into account. Second, the behaviour / state of a driver and functional flow / state of ADS and the interactions between them are modelled to understand the context where the ADS requests to delegate the driving authority to a driver. Finally, the proposed architecture of the ADS is verified under the simulations based on the emergency braking scenarios. In the verification process using simulation, we have derived the necessary condition for safe delegation of driving authority is that the ADS should assist s driver even after delegating driving authority to a driver who has not enough capability to regain control of the driving task.

  14. Chapter 18: Variable Frequency Drive Evaluation Protocol

    Energy Technology Data Exchange (ETDEWEB)

    Romberger, J.

    2014-11-01

    An adjustable-speed drive (ASD) includes all devices that vary the speed of a rotating load, including those that vary the motor speed and linkage devices that allow constant motor speed while varying the load speed. The Variable Frequency Drive Evaluation Protocol presented here addresses evaluation issues for variable-frequency drives (VFDs) installed on commercial and industrial motor-driven centrifugal fans and pumps for which torque varies with speed. Constant torque load applications, such as those for positive displacement pumps, are not covered by this protocol. Other ASD devices, such as magnetic drive, eddy current drives, variable belt sheave drives, or direct current motor variable voltage drives, are also not addressed. The VFD is by far the most common type of ASD hardware. With VFD speed control on a centrifugal fan or pump motor, energy use follows the affinity laws, which state that the motor electricity demand is a cubic relationship to speed under ideal conditions. Therefore, if the motor runs at 75% speed, the motor demand will ideally be reduced to 42% of full load power; however, with other losses it is about 49% of full load power.

  15. Graphical Visualization of Human Exploration Capabilities

    Science.gov (United States)

    Rodgers, Erica M.; Williams-Byrd, Julie; Arney, Dale C.; Simon, Matthew A.; Williams, Phillip A.; Barsoum, Christopher; Cowan, Tyler; Larman, Kevin T.; Hay, Jason; Burg, Alex

    2016-01-01

    of planned future work to modify the computer program to include additional data and of alternate capability roadmap formats currently under consideration.

  16. The influence of music on mental effort and driving performance.

    Science.gov (United States)

    Ünal, Ayça Berfu; Steg, Linda; Epstude, Kai

    2012-09-01

    The current research examined the influence of loud music on driving performance, and whether mental effort mediated this effect. Participants (N=69) drove in a driving simulator either with or without listening to music. In order to test whether music would have similar effects on driving performance in different situations, we manipulated the simulated traffic environment such that the driving context consisted of both complex and monotonous driving situations. In addition, we systematically kept track of drivers' mental load by making the participants verbally report their mental effort at certain moments while driving. We found that listening to music increased mental effort while driving, irrespective of the driving situation being complex or monotonous, providing support to the general assumption that music can be a distracting auditory stimulus while driving. However, drivers who listened to music performed as well as the drivers who did not listen to music, indicating that music did not impair their driving performance. Importantly, the increases in mental effort while listening to music pointed out that drivers try to regulate their mental effort as a cognitive compensatory strategy to deal with task demands. Interestingly, we observed significant improvements in driving performance in two of the driving situations. It seems like mental effort might mediate the effect of music on driving performance in situations requiring sustained attention. Other process variables, such as arousal and boredom, should also be incorporated to study designs in order to reveal more on the nature of how music affects driving. Copyright © 2012 Elsevier Ltd. All rights reserved.

  17. Polar Direct Drive

    Science.gov (United States)

    Skupsky, S.

    2003-10-01

    Direct drive offers the potential of higher target gain on the National Ignition Facility (NIF) than x-ray drive: The initial direct-drive target design had a 1-D gain of 45 and consisted primarily of a pure cryogenic DT shell. Using the expected levels of target and laser nonuniformities for the NIF, two-dimensional (2-D) hydrodynamic simulations predicted target gains around 30.(P.W. McKenty et al.), Phys. Plasmas 8, 2315 (2001). More-recent designs have shown that higher target gains could be obtained by replacing a portion of the DT shell with ``wetted'' CH foam and by using adiabat shaping: (1) Higher-Z material (C) in the foam increases laser absorption by about 40% (from 60% absorption to 85%).(S. Skupsky et al.), in Inertial Fusion Sciences and Applications 2001, edited by K. Tanaka et al. (Elsevier, Paris, 2002), p. 240. (2) Adiabat shaping allows the main portion of the fuel to be placed on a lower adiabat without compromising target stability.(V.N. Goncharov et al.), Phys. Plasmas 10, 1906 (2003). These direct-drive concepts can be tested on the NIF, long before that facility is converted to a direct-drive (spherically symmetric) irradiation configuration. Using the NIF x-ray-drive beam configuration, some of the near-polar beams could be pointed to better illuminate the target's equator. These more-oblique, equatorial beams will have lower absorption and reduced drive efficiency than the polar beams. One strategy to compensate for the difference in polar and equatorial drive is to reduce the irradiation at the poles and employ different pulse shapes to accommodate the time-dependent variations in drive and absorption. This concept of polar direct drive (PDD) has been studied using the 2-D hydrocode DRACO to determine the requirements for achieving ignition and moderate target gain for the NIF. Experiments on the OMEGA laser will examine the effects of oblique irradiation on target drive. Results of simulations for different direct-drive target designs

  18. Electrical motor/generator drive apparatus and method

    Science.gov (United States)

    Su, Gui Jia

    2013-02-12

    The present disclosure includes electrical motor/generator drive systems and methods that significantly reduce inverter direct-current (DC) bus ripple currents and thus the volume and cost of a capacitor. The drive methodology is based on a segmented drive system that does not add switches or passive components but involves reconfiguring inverter switches and motor stator winding connections in a way that allows the formation of multiple, independent drive units and the use of simple alternated switching and optimized Pulse Width Modulation (PWM) schemes to eliminate or significantly reduce the capacitor ripple current.

  19. A Control Law Definition of the Open Loop Stepping Electric Drive

    Directory of Open Access Journals (Sweden)

    A. B. Krasovskii

    2015-01-01

    Full Text Available The paper considers an open loop stepping electric drive (SEP with electric crushing of a step and motor fed from the controlled current invertor which should meet the requirement that is to trial a free-form guided trajectory with a split-hair accuracy. It is shown that with traditional programmed control, when the SEP forms motor phase currents of identical amplitude and variable frequency proportional to the set speed of movement, there may be considerable errors reducing a trial accuracy of the set movement trajectory, dynamic indicators provoking oscillatory processes, and even loss of motor synchronism because influence on a dynamic moment of the motor is impossible.The paper offers and proves a new way to define a control algorithm adequate to drive parameters and programmed trajectory of movement, providing error minimization and thereby increasing trial accuracy of set parameters of movement and expanding dynamic capabilities of a drive. The essence of the offered way is to use a modified mathematical model of a drive in d,q coordinates with a motor fed by the current source. In this model a programmed trajectory of movement is chosen as an input action while solving the appropriate equations defines the necessary law of control. The paper describes a developed simulation model of the stepping electric drive in the environment of MATLAB – SIMULINK, which has been used to verify and prove an efficiency of the offered method to define a control law via typical examples.It is established that no error trial of set movement trajectory in case it has breaks (jogs is technically unfeasible, as it demands an infinitely high forcing voltage of the power supply to maintain the instant positive or negative phase shifts of currents formed in the motor windings.The obtained results can be used in designing programmable precision SEPs in robots, numerically controlled machine tools, and assembly equipment.

  20. The latest technical solutions in rail vehicles drives

    Directory of Open Access Journals (Sweden)

    Andrzejewski Maciej

    2017-01-01

    Full Text Available The article discusses the latest trends and solutions used in the offers of rail vehicles manufacturers. The study is mainly concerned with the technical solutions used in hybrid rail vehicles, whose development has become one of the priorities for the development of rail vehicles in the European Union in recent years. Stricter emissions standards for harmful compounds in the European Union have forced manufacturers to use increasingly sophisticated technology, including hybrid drives and alternative fuels. The products and solutions offered by the major manufacturers on the market, along with their capabilities and future applications are described. The predicted trends in the development of propulsion technology for rail and road-rail vehicles are also indicated in view of the current legislative aspirations among the EU Member States.

  1. FLC based adjustable speed drives for power quality enhancement

    Directory of Open Access Journals (Sweden)

    Sukumar Darly

    2010-01-01

    Full Text Available This study describes a new approach based on fuzzy algorithm to suppress the current harmonic contents in the output of an inverter. Inverter system using fuzzy controllers provide ride-through capability during voltage sags, reduces harmonics, improves power factor and high reliability, less electromagnetic interference noise, low common mode noise and extends output voltage range. A feasible test is implemented by building a model of three-phase impedance source inverter, which is designed and controlled on the basis of proposed considerations. It is verified from the practical point of view that these new approaches are more effective and acceptable to minimize the harmonic distortion and improves the quality of power. Due to the complex algorithm, their realization often calls for a compromise between cost and performance. The proposed optimizing strategies may be applied in variable-frequency dc-ac inverters, UPSs, and ac drives.

  2. The Shipbuilding Industries of the U.S. and U.S.S.R. as Bases for National Maritime Policies: Current Capabilities and Surge Demand Potential. Volume I. Main Report

    Science.gov (United States)

    1981-02-01

    Structurals (MIL) 10 10 16 24 12 16 10 12 13 2. Alloy Steel HY80 Plate 12 14 24 26 20 20 16 16 20 Extrusions (MIL) 40 24 24 30 42 26 20 24 24 HY80 ...industries. However, for some specialized alloy steel plates such as HY80 for submarine hulls, the shipbuilders are almost the only users. The firms in...National Steel and Shipbuilding Company .......... .- 7 3-2 Ingalls Shipbuilding (Division of Litton Systemsinc - 3-3 Current (1980) Lead Times for

  3. Assessment: A Driving Force.

    Science.gov (United States)

    Rakow, Steven J.

    1992-01-01

    Asserts that educational assessment drives the curriculum. Thus, assessment is very important in contemplating reform in science education. Assessment should be an integral part of the instructional process, utilizing diagnostic testing, monitoring, and summative evaluations. (PR)

  4. Driving in a womb

    NARCIS (Netherlands)

    Anonymous

    Drive thousands of kilometres on just a litre of fuel? During the annual Shell eco-marathon at the end of May, schoolchildren and students – including a team from TU Delft – demonstrated that it can indeed be done.

  5. Stability Analysis of BLDC Motor Drive based on Input Shaping

    Directory of Open Access Journals (Sweden)

    M.Murugan

    2013-10-01

    Full Text Available The main objective of this work is to analyze the brushless DC (BLDC motor drive system with input shaping using classical control theory. In this paper, different values of damping ratio are used to understand the generalized drive performance. The transient response of the BLDC motor drive system is analyzed using time response analysis. The dynamic behaviour and steady state performance of the BLDC motor drive system is judged and compared by its steady state error to various standard test signals. The relative stability of this drive system is determined by Bode Plot. These analysis spotlights that it is possible to obtain a finite-time setting response without oscillation in BLDC motor drive by applying input in four steps of different amplitude to the drive system. These analyses are helpful to design a precise speed control system and current control system for BLDC motor drive with fast response. The Matlab/Simulink software is used to perform the simulation.

  6. Instant Google Drive starter

    CERN Document Server

    Procopio, Mike

    2013-01-01

    This book is a Starter which teaches you how to use Google Drive practically. This book is perfect for people of all skill levels who want to enjoy the benefits of using Google Drive to safely store their files online and in the cloud. It's also great for anyone looking to learn more about cloud computing in general. Readers are expected to have an Internet connection and basic knowledge of using the internet.

  7. Marine winch drive systems

    Energy Technology Data Exchange (ETDEWEB)

    Clifford, M.; Smith, P.M.

    1983-12-01

    In the design of marine winch drive systems, efficiency, controllability, compactness and component layout flexibility are major considerations. This paper discusses design concepts aimed at achieving the above considerations in the design of variable speed, hydrostatic, marine winch drive systems. These concepts utilize a high pressure, load sensing pump, and a low-speed, high-torque (LSHT), radial-piston, hydraulic motor. These components are then shown applied in several open circuit hydrostatic power transmission systems.

  8. Knowledge Management Capabilities Rubrics

    Directory of Open Access Journals (Sweden)

    Azizah B.A. Rahman

    2011-01-01

    Full Text Available Problem statement: Recently researchers discerned the vitality and importance of Knowledge Management Capabilities (KMC evaluation in organizations. In fact evaluation of KMC helps to prevent failure in Knowledge Management (KM projects. Approach: One of the most popular methods in the phase of evaluating KMC is Fuzzy method which evaluates seven attributes of KMC. Fuzzy needs KM experts to give their opinion about these attributes as input data. However in some organizations these experts are not available. Results: Therefore in this study a rubric matrix is developed as an assessment tool with ordered rank (very high, medium and very low of descriptive characteristics of criteria (seven attributes that organizations wish to evaluate. Conclusion: This rubric is applicable for members of an organization which are not familiar completely with KMC and also will be maintained by analyzing and surveying many different researches.

  9. PHOBOS physics capabilities

    Energy Technology Data Exchange (ETDEWEB)

    Baker, M.D. [Massachusetts Institute of Technology, Cambridge, MA (United States)

    1995-07-15

    PHOBOS is the name of a detector and of a research program to study systematically the physics of relativistic heavy-ion collisions over a large range of impact parameters and nuclear species. Collisions with a center mass energy of 200 A GeV at RHIC are expected to produce the highest energy densities ever accessible in the laboratory. In this writeup, the authors outline the physics capabilities of the PHOBOS detector and describe the detector design in terms of the general philosophy behind the PHOBOS research program. In order to make the discussion concrete, they then focus on two specific examples of physics measurements that they plan to make at RHIC: dN/d{eta} for charged particles and the mass spectrum from {phi} {yields} K{sup +}K{sup {minus}} decays.

  10. Dementia and driving.

    Science.gov (United States)

    O'Neill, D; Neubauer, K; Boyle, M; Gerrard, J; Surmon, D; Wilcock, G K

    1992-04-01

    Many European countries test cars, but not their drivers, as they age. There is evidence to suggest that human factors are more important than vehicular factors as causes of motor crashes. The elderly also are involved in more accidents per distance travelled than middle-aged drivers. As the UK relies on self-certification of health by drivers over the age of 70 years, we examined the driving practices of patients with dementia attending a Memory Clinic. Nearly one-fifth of 329 patients with documented dementia continued to drive after the onset of dementia, and impaired driving ability was noted in two-thirds of these. Their families experienced great difficulty in persuading patients to stop driving, and had to invoke outside help in many cases. Neuropsychological tests did not help to identify those who drove badly while activity of daily living scores were related to driving ability. These findings suggest that many patients with dementia drive in an unsafe fashion after the onset of the illness. The present system of self-certification of health by the elderly for driver-licensing purposes needs to be reassessed.

  11. Self-driving carsickness.

    Science.gov (United States)

    Diels, Cyriel; Bos, Jelte E

    2016-03-01

    This paper discusses the predicted increase in the occurrence and severity of motion sickness in self-driving cars. Self-driving cars have the potential to lead to significant benefits. From the driver's perspective, the direct benefits of this technology are considered increased comfort and productivity. However, we here show that the envisaged scenarios all lead to an increased risk of motion sickness. As such, the benefits this technology is assumed to bring may not be capitalised on, in particular by those already susceptible to motion sickness. This can negatively affect user acceptance and uptake and, in turn, limit the potential socioeconomic benefits that this emerging technology may provide. Following a discussion on the causes of motion sickness in the context of self-driving cars, we present guidelines to steer the design and development of automated vehicle technologies. The aim is to limit or avoid the impact of motion sickness and ultimately promote the uptake of self-driving cars. Attention is also given to less well known consequences of motion sickness, in particular negative aftereffects such as postural instability, and detrimental effects on task performance and how this may impact the use and design of self-driving cars. We conclude that basic perceptual mechanisms need to be considered in the design process whereby self-driving cars cannot simply be thought of as living rooms, offices, or entertainment venues on wheels.

  12. FOREIGN DRIVING LICENCES IN FRANCE

    CERN Multimedia

    Service des relations avec les Pays Hôtes

    2000-01-01

    1. PERSONS RESIDING IN FRANCE1.1 National driving licences from countries belonging to the EEAa) ValidityCurrent national driving licences issued by a country belonging to the European Economic Area (here inafter called EEA) are, in principle, valid in France. N.B. : The countries belonging to the EEA are Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Liechtenstein, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden and the United Kingdom.b)\tRegistrationTo ensure that all the conditions of validity in France have been met, holders of driving licences issued by a country belonging to the EEA, who reside in France (i.e. hold a residence permit issued by a Préfecture, or a carte spéciale issued by the French Ministry of Foreign Affairs, which is equivalent to a residence permit), can have their licences registered with the Préfecture of the department where they live (for Ain, call 04 74 32 30 00, for Haute Savoie call 04 50 33 ...

  13. Foreign driving licences in France

    CERN Multimedia

    HR Department

    2009-01-01

    The following information is subject to possible amendments decided by the competent French authorities. Those wishing to undertake the necessary steps with the prefectural services of the Departments of the Ain and Haute-Savoie may obtain information by calling the following numbers: + 33 4 74 32 30 65 for the Ain and + 33 4 50 33 60 00 for Haute-Savoie. 1. PERSONS RESIDING IN FRANCE 1.1 Driving licences issued by a State belonging to the EU or the EEA a) Recognition on French territory All currently valid driving licences issued by States belonging to the European Union (EU) or to the European Economic Area (EEA) are generally valid for driving on French territory. However, if the licence was originally obtained in exchange for a licence issued by a State not belonging to the EU or to the EEA and with which France has not concluded a reciprocity agreement, it will be recognised for a maximum of one year following the date of establishment of normal residence in France ...

  14. FOREIGN DRIVING LICENCES IN FRANCE

    CERN Document Server

    DSU Unit

    2008-01-01

    The following information is provided subject to possible amendments decided by the competent French authorities. Those wishing to undertake the necessary steps with the prefectural services of the Departments of Ain and Haute-Savoie may obtain information by calling the following numbers: + 33 474 32 30 65 for Ain and + 33 450 33 60 00 for Haute-Savoie. 1. PEOPLE RESIDING IN FRANCE 1.1 Driving licences issued by a state belonging to the EU or the EEA a) Recognition on French territory All currently valid driving licences issued by States belonging to the European Union (EU) or to the European Economic Area (EEA) are generally valid for driving on French territory. However, if the licence was originally obtained in exchange for a licence issued by a State not belonging to the EU or to the EEA with which France has not concluded a reciprocity agreement, it is recognised only up to one year following the date of establishment of normal residence in France (date of the first special residence permit issu...

  15. Foreign driving licences in Switzerland

    CERN Multimedia

    2009-01-01

    1. Persons residing in Switzerland 1.1 Holders of a B, C, D, E or P-type "carte de légitimation" For holders of a B, C, D, E or P-type "carte de légitimation" issued by the Swiss Federal Department for Foreign Affairs (DFAE), current non-Swiss national driving licences are valid in Switzerland. (see the official news about the new "Carte de légitimation P") If they so wish, holders of such driving licences may apply to the relevant road licensing authority in the canton where they live (Service des Automobiles et de la Navigation; for Geneva call + 41 22 388 30 30, website http://www.geneve.ch/san; for Vaud call + 41 21 316 82 10, website http://www.san.vd.ch/index.html) to exchange their driving licence for an equivalent Swiss licence (they must pass a test if they are not citizens of countries with which Switzerland has concluded an agreement on this matter, e.g. Member States of the European Union, the United States and Japan). However, such an exchange is not possible...

  16. An HTS flux pump operated by directly driving a superconductor into flux flow region in the E- J curve

    Science.gov (United States)

    Geng, Jianzhao; Coombs, T. A.

    2016-09-01

    High-T c superconducting (HTS) flux pumps are capable of compensating the persistent current decay in HTS magnets without electrical contact. In this paper, following work on a low-T c superconducting self-switching flux pump, we propose a new HTS flux pump by directly driving a high-T c superconductor into the flux flow region in the E- J curve. The flux pump consists of a transformer which has a superconducting secondary winding shorted by an YBCO-coated conductor bridge. A high alternating current with a much higher positive peak value than the negative peak value is induced in the secondary winding. The current always drives the bridge superconductor into the flux flow region only at around its positive peak value, thus resulting in flux pumping. The proposed flux pump is much simpler than existing HTS flux pumps.

  17. Developing Collaborative Product Development Capabilities

    DEFF Research Database (Denmark)

    Mahnke, Volker; Tran, Yen

    2012-01-01

    Collaborative product development capabilities support a company’s product innovation activities. In the context of the fast fashion sector, this paper examines the development of the product development capabilities (PDC) that align product development capabilities in a dual innovation context, ......-level, simultaneous learning processes and highlight the role of human agency in capability development with partners. Building on our analyses, we advance propositions for future research and managerial practices on developing dynamic collaboration capabilities....

  18. [Nondestructive Evaluation (NDE) Capabilities

    Science.gov (United States)

    Born, Martin

    2010-01-01

    These poster boards display the United Space Alliance's (USA) systems and equipment used for Nondestructive Evaluation. These include: (1) the Robotic Inspection Facility, (2) CAT-Scan and Laminography, (3) Laser Surface Profilometry, (4) Remote Eddy Current, (5) Ultrasonic Phased Array, (7) Infrared Flash Thermography, and (8) Backscatter X-Ray (BSX)

  19. Magnetostrictive direct drive motor

    Science.gov (United States)

    Naik, Dipak; Dehoff, P. H.

    1991-01-01

    Highly magnetostrictive materials such as Tb.3Dy.7Fe2, commercially known as TERFENOL-D, have been used to date in a variety of devices such as high power actuators and linear motors. The larger magnetostriction available in twinned single crystal TERFENOL-D, approx. 2000 ppm at moderate magnetic field strengths, makes possible a new generation of magnetomechanical devices. NASA researchers are studying the potential of this material as the basis for a direct microstepping rotary motor with torque densities on the order of industrial hydraulics and five times greater than that of the most efficient, high power electric motors. Such a motor would be a micro-radian stepper, capable of precision movements and self-braking in the power-off state. Innovative mechanical engineering techniques are juxtaposed on proper magnetic circuit design to reduce losses in structural flexures, inertias, thermal expansions, eddy currents, and magneto-mechanical coupling, thus optimizing motor performance and efficiency. Mathematical models are presented, including magnetic, structural, and both linear and nonlinear dynamic calculations and simulations. In addition, test results on prototypes are presented.

  20. Investigation of Current Driven Loudspeakers

    DEFF Research Database (Denmark)

    Schneider, Henrik; Agerkvist, Finn T.; Knott, Arnold

    2015-01-01

    Current driven loudspeakers have previously been investigated but the literature is limited and the advantages and disadvantages are yet to be fully identified. This paper makes use of a non-linear loudspeaker model to analyse loudspeakers with distinct non-linear characteristics under voltage...... and current drive. A multi tone test signal is used in the evaluation of the driving schemes since it resembles audio signals to a higher degree than the signals used in total harmonic distortion and intermodulation distortion test methods. It is found that current drive is superior over voltage drive in a 5...