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Sample records for strong radial electric

  1. Inward transport of a toroidally confined plasma subject to strong radial electric fields

    Science.gov (United States)

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

    1977-01-01

    The paper aims at showing that the density and confinement time of a toroidal plasma can be enhanced by radial electric fields far stronger than the ambipolar values, and that, if such electric fields point into the plasma, radially inward transport can result. The investigation deals with low-frequency fluctuation-induced transport using digitally implemented spectral analysis techniques and with the role of strong applied radial electric fields and weak vertical magnetic fields on plasma density and particle confinement times in a Bumpy Torus geometry. Results indicate that application of sufficiently strong radially inward electric fields results in radially inward fluctuation-induced transport into the toroidal electrostatic potential well; this inward transport gives rise to higher average electron densities and longer particle confinement times in the toroidal plasma.

  2. The role of fluctuation-induced transport in a toroidal plasma with strong radial electric fields

    Science.gov (United States)

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

    1981-01-01

    Previous work employing digitally implemented spectral analysis techniques is extended to demonstrate that radial fluctuation-induced transport is the dominant ion transport mechanism in an electric field dominated toroidal plasma. Such transport can be made to occur against a density gradient, and hence may have a very beneficial effect on confinement in toroidal plasmas of fusion interest. It is shown that Bohm or classical diffusion down a density gradient, the collisional Pedersen-current mechanism, and the collisionless electric field gradient mechanism described by Cole (1976) all played a minor role, if any, in the radial transport of this plasma.

  3. Interactions between Radial Electric Field, Transport and Structure in Helical Plasmas

    International Nuclear Information System (INIS)

    Ida, Katsumi and others

    2006-01-01

    Control of the radial electric field is considered to be important in helical plasmas, because the radial electric field and its shear are expected to reduce neoclassical and anomalous transport, respectively. Particle and heat transport, that determines the radial structure of density and electron profiles, sensitive to the structure of radial electric field. On the other hand, the radial electric field itself is determined by the plasma parameters. In general, the sign of the radial electric field is determined by the plasma collisionality, while the magnitude of the radial electric field is determined by the temperature and/or density gradients. Therefore the structure of radial electric field and temperature and density are strongly coupled through the particle and heat transport and formation mechanism of radial electric field. Interactions between radial electric field, transport and structure in helical plasmas is discussed based on the experiments on Large Helical Device

  4. Radial electric fields for improved tokamak performance

    International Nuclear Information System (INIS)

    Downum, W.B.

    1981-01-01

    The influence of externally-imposed radial electric fields on the fusion energy output, energy multiplication, and alpha-particle ash build-up in a TFTR-sized, fusing tokamak plasma is explored. In an idealized tokamak plasma, an externally-imposed radial electric field leads to plasma rotation, but no charge current flows across the magnetic fields. However, a realistically-low neutral density profile generates a non-zero cross-field conductivity and the species dependence of this conductivity allows the electric field to selectively alter radial particle transport

  5. Control of the radial electric field shear by modification of the magnetic field configuration in LHD

    International Nuclear Information System (INIS)

    Ida, K.; Yoshinuma, M.; Yokoyama, M.

    2005-01-01

    Control of the radial electric field, E γ , is considered to be important in helical plasmas, because the radial electric field and its shear are expected to reduce neoclassical and anomalous transport, respectively. In general, the radial electric field can be controlled by changing the collisionality, and positive or negative electric field have been obtained by decreasing or increasing the electron density, respectively. Although the sign of the radial electric field can be controlled by changing the collisionality, modification of the magnetic field is required to achieve further control of the radial electric field, especially producing a strong radial electric field shear. In the Large Helical Device (LHD) the radial electric field profiles are shown to be controlled by the modification of the magnetic field by 1) changing the radial profile of the helical ripples, ε h , 2) creating a magnetic island with an external perturbation field coil and 3) changing the local island divertor coil current. (author)

  6. Control of the radial electric field shear by modification of the magnetic field configuration in LHD

    International Nuclear Information System (INIS)

    Ida, K.; Yoshinuma, M.; Yokoyama, M.

    2005-01-01

    Control of the radial electric field, E r , is considered to be important in helical plasmas, because the radial electric field and its shear are expected to reduce neoclassical and anomalous transport, respectively. In general, the radial electric field can be controlled by changing the collisionality, and positive or negative electric fields have been obtained by decreasing or increasing the electron density, respectively. Although the sign of the radial electric field can be controlled by changing the collisionality, modification of the magnetic field is required to achieve further control of the radial electric field, especially to produce a strong radial electric field shear. In the Large Helical Device (LHD) the radial electric field profiles are shown to be controlled by the modification of the magnetic field by (1) changing the radial profile of the effective helical ripples, ε h (2) creating a magnetic island with an external perturbation field coil and (3) changing the local island divertor coil current

  7. Radial oscillations of neutron stars in strong magnetic fields

    Indian Academy of Sciences (India)

    The eigen frequencies of radial pulsations of neutron stars are calculated in a strong magnetic field. At low densities we use the magnetic BPS equation of state (EOS) similar to that obtained by Lai and Shapiro while at high densities the EOS obtained from the relativistic nuclear mean field theory is taken and extended to ...

  8. Radial-Electric-Field Piezoelectric Diaphragm Pumps

    Science.gov (United States)

    Bryant, Robert G.; Working, Dennis C.; Mossi, Karla; Castro, Nicholas D.; Mane, Pooma

    2009-01-01

    In a recently invented class of piezoelectric diaphragm pumps, the electrode patterns on the piezoelectric diaphragms are configured so that the electric fields in the diaphragms have symmetrical radial (along-the-surface) components in addition to through-the-thickness components. Previously, it was accepted in the piezoelectric-transducer art that in order to produce the out-of-plane bending displacement of a diaphragm needed for pumping, one must make the electric field asymmetrical through the thickness, typically by means of electrodes placed on only one side of the piezoelectric material. In the present invention, electrodes are placed on both sides and patterned so as to produce substantial radial as well as through-the-thickness components. Moreover, unlike in the prior art, the electric field can be symmetrical through the thickness. Tests have shown in a given diaphragm that an electrode configuration according to this invention produces more displacement than does a conventional one-sided electrode pattern. The invention admits of numerous variations characterized by various degrees of complexity. Figure 1 is a simplified depiction of a basic version. As in other piezoelectric diaphragm pumps of similar basic design, the prime mover is a piezoelectric diaphragm. Application of a suitable voltage to the electrodes on the diaphragm causes it to undergo out-of-plane bending. The bending displacement pushes a fluid out of, or pulls the fluid into, a chamber bounded partly by the diaphragm. Also as in other diaphragm pumps in general, check valves ensure that the fluid flows only in through one port and only out through another port.

  9. Electrophoresis in strong electric fields.

    Science.gov (United States)

    Barany, Sandor

    2009-01-01

    Two kinds of non-linear electrophoresis (ef) that can be detected in strong electric fields (several hundred V/cm) are considered. The first ("classical" non-linear ef) is due to the interaction of the outer field with field-induced ionic charges in the electric double layer (EDL) under conditions, when field-induced variations of electrolyte concentration remain to be small comparatively to its equilibrium value. According to the Shilov theory, the non-linear component of the electrophoretic velocity for dielectric particles is proportional to the cubic power of the applied field strength (cubic electrophoresis) and to the second power of the particles radius; it is independent of the zeta-potential but is determined by the surface conductivity of particles. The second one, the so-called "superfast electrophoresis" is connected with the interaction of a strong outer field with a secondary diffuse layer of counterions (space charge) that is induced outside the primary (classical) diffuse EDL by the external field itself because of concentration polarization. The Dukhin-Mishchuk theory of "superfast electrophoresis" predicts quadratic dependence of the electrophoretic velocity of unipolar (ionically or electronically) conducting particles on the external field gradient and linear dependence on the particle's size in strong electric fields. These are in sharp contrast to the laws of classical electrophoresis (no dependence of V(ef) on the particle's size and linear dependence on the electric field gradient). A new method to measure the ef velocity of particles in strong electric fields is developed that is based on separation of the effects of sedimentation and electrophoresis using videoimaging and a new flowcell and use of short electric pulses. To test the "classical" non-linear electrophoresis, we have measured the ef velocity of non-conducting polystyrene, aluminium-oxide and (semiconductor) graphite particles as well as Saccharomice cerevisiae yeast cells as a

  10. Radial Distribution Functions of Strongly Coupled Two-Temperature Plasmas

    Science.gov (United States)

    Shaffer, Nathaniel R.; Tiwari, Sanat Kumar; Baalrud, Scott D.

    2017-10-01

    We present tests of three theoretical models for the radial distribution functions (RDFs) in two-temperature strongly coupled plasmas. RDFs are useful in extending plasma thermodynamics and kinetic theory to strong coupling, but they are usually known only for thermal equilibrium or for approximate one-component model plasmas. Accurate two-component modeling is necessary to understand the impact of strong coupling on inter-species transport, e.g., ambipolar diffusion and electron-ion temperature relaxation. We demonstrate that the Seuferling-Vogel-Toeppfer (SVT) extension of the hypernetted chain equations not only gives accurate RDFs (as compared with classical molecular dynamics simulations), but also has a simple connection with the Yukawa OCP model. This connection gives a practical means to recover the structure of the electron background from knowledge of the ion-ion RDF alone. Using the model RDFs in Effective Potential Theory, we report the first predictions of inter-species transport coefficients of strongly coupled plasmas far from equilibrium. This work is supported by NSF Grant No. PHY-1453736, AFSOR Award No. FA9550-16-1-0221, and used XSEDE computational resources.

  11. Radial electrical field effects in TJ-II. (Preliminary study)

    International Nuclear Information System (INIS)

    Guasp, J.

    1996-01-01

    The influence of the radial electric field upon the neoclassical transport coefficients of TJ-II helical axis Stellarator has been calculated as well on the microwave heating stage (ECRH) as on the neutral injection one (NBI). The influence of the solutions for the self-consistent ambipolar field on confinement times and temperatures has been studied by means of a zero-dimensional energy balance. The simultaneous presence of two roots, the electronic and the ionic one, is observed for the ECRH phase, while for NBI only the ionic root appears, although with a strong field intensity that could produce a favourable effect on confinement. The interest and need of the extension of these calculations to include radial profile effects by using spatial dependent transport codes in stressed

  12. Physical mechanism determining the radial electric field and its radial structure in a toroidal plasma

    International Nuclear Information System (INIS)

    Ida, Katsumi; Miura, Yukitoshi; Itoh, Sanae

    1994-10-01

    Radial structures of plasma rotation and radial electric field are experimentally studied in tokamak, heliotron/torsatron and stellarator devices. The perpendicular and parallel viscosities are measured. The parallel viscosity, which is dominant in determining the toroidal velocity in heliotron/torsatron and stellarator devices, is found to be neoclassical. On the other hand, the perpendicular viscosity, which is dominant in dictating the toroidal rotation in tokamaks, is anomalous. Even without external momentum input, both a plasma rotation and a radial electric field exist in tokamaks and heliotrons/torsatrons. The observed profiles of the radial electric field do not agree with the theoretical prediction based on neoclassical transport. This is mainly due to the existence of anomalous perpendicular viscosity. The shear of the radial electric field improves particle and heat transport both in bulk and edge plasma regimes of tokamaks. (author) 95 refs

  13. Measurement of the radial electric field in the ASDEX tokamak

    International Nuclear Information System (INIS)

    Field, A.R.; Fussmann, G.; Hofmann, J.V.

    1990-12-01

    The radial electric field (E Τ ) at the plasma periphery is determined by measuring the drift velocities of low-Z impurities ions (BIV, CIII and HeII). The measurements are performed with a scannable mirror system which allows the determination of the poloidal, perpendicular (to B vector) and toroidal components of the drift velocities from the differential Doppler shift of visible line emission observed along opposing viewing directions. The principle of the measurement is investigated in detail. In particular, it is shown that for radially localised emission shells there exits a line of sight oriented perpendicular to B vector along which E Τ may be inferred directly from the observed Doppler shift of the line emission. Along such a line of sight the net contribution to the shift from the diamagnetic drift and the radial gradient of the excitation probability is negligible. During the Ohmic- and L-phases the perpendicular drift velocity of the BIV ions measured approximately 2 cm inside the separatrix is small (≤ 2 kms -1 ) and in the ion diamagnetic drift direction. However, at the L → H-Mode transition it changes sign and begins to increase on the time-scale of the edge pressure gradients reaching the highest values at the end of the H * -phase. From these high perpendicular drift velocities it is infered that, in the H-mode, there exists a strong negative radial electric field (vertical strokeE τ vertical stroke ≤ kVm -1 ) just inside the separatrix. The dependence of the drift velocity of the BIV ions and E Τ on the NBI-heating power and the magnitude and direction of the plasma current and the magnetic field is investigated. (orig.)

  14. Effects of applied dc radial electric fields on particle transport in a bumpy torus plasma

    Science.gov (United States)

    Roth, J. R.

    1978-01-01

    The influence of applied dc radial electric fields on particle transport in a bumpy torus plasma is studied. The plasma, magnetic field, and ion heating mechanism are operated in steady state. Ion kinetic temperature is more than a factor of ten higher than electron temperature. The electric fields raise the ions to energies on the order of kilovolts and then point radially inward or outward. Plasma number density profiles are flat or triangular across the plasma diameter. It is suggested that the radial transport processes are nondiffusional and dominated by strong radial electric fields. These characteristics are caused by the absence of a second derivative in the density profile and the flat electron temperature profiles. If the electric field acting on the minor radius of the toroidal plasma points inward, plasma number density and confinement time are increased.

  15. Effect of the radial electric field on turbulence

    International Nuclear Information System (INIS)

    Carreras, B.A.; Lynch, V.E.

    1990-01-01

    For many years, the neoclassical transport theory for three- dimensional magnetic configurations, such as magnetic mirrors, ELMO Bumpy Tori (EBTs), and stellarators, has recognized the critical role of the radial electric field in the confinement. It was in these confinement devices that the first experimental measurements of the radial electric field were made and correlated with confinement losses. In tokamaks, the axisymmetry implies that the neoclassical fluxes are ambipolar and, as a consequence, independent of the radial electric field. However, axisymmetry is not strict in a tokamak with turbulent fluctuations, and near the limiter ambipolarity clearly breaks down. Therefore, the question of the effect of the radial electric field on tokamak confinement has been raised in recent years. In particular, the radial electric field has been proposed to explain the transition from L-mode to H-mode confinement. There is some initial experimental evidence supporting this type of explanation, although there is not yet a self-consistent theory explaining the generation of the electric field and its effect on the transport. Here, a brief review of recent results is presented. 27 refs., 4 figs

  16. Effects of Radial Electric Fields on ICRF Waves

    International Nuclear Information System (INIS)

    Phillips, C.K.; Hosea, J.C.; Ono, M.; Wilson, J.R.

    2001-01-01

    Equilibrium considerations infer that large localized radial electric fields are associated with internal transport barrier structures in tokamaks and other toroidal magnetic confinement configurations. In this paper, the effects of an equilibrium electric field on fast magnetosonic wave propagation are considered in the context of a cold plasma model

  17. Radial and tangential friction in heavy ion strongly damped collisions

    International Nuclear Information System (INIS)

    Jain, A.K.; Sarma, N.

    1979-01-01

    Deeply inelastic heavy ion collisions have been successfully described in terms of a nucleon exchange mechanism between two nucleon clouds. This model has also predicted the large angular momentum that is induced in the colliding nuclei. However computations were simplified in the earlier work by assuming that the friction was perturbation on the elastic scattering trajectory. Results of a more rigorous calculation are reported and the effect of modification of the trajectory on the energy transfer, the angular momentum induced and on the ratio of the radial to the tangential friction coefficients is reported. (auth.)

  18. The impact of the biasing radial electric field on the SOL in a divertor tokamak

    International Nuclear Information System (INIS)

    Rozhansky, V.; Tendler, M.

    1993-01-01

    Strong radial electric field can be induced within the SOL in a divertor tokamak by applying a voltage to divertor plates with respect to the first wall. This biasing scheme results in the strong radial electric field which is much larger than the natural electric field, usually of the order T e /e. Experiments employing this biasing scheme were carried out on the tokamak TdeV. Many interesting effects such as - modifications of the density profile and radial transport of impurities as a function of the polarity and the magnitude of the biasing voltage, the generation of the flux surface average toroidal rotation proportional to the applied voltage, redistribution of the plasma outflow onto divertor plates and so on - were demonstrated to result from the biasing. Furthermore, in contrast to studies carried out employing a different biasing scheme which primarily results in a poloidal electric field, the strong radial electric field impacts more significantly within SOL than the poloidal electric field. Here, we aim to show that the main effects observed experimentally follow from the analysis, provided continuity and momentum balances are employed invoking anomalous viscosity and inertia. (author) 4 refs

  19. Ion confinement and transport in a toroidal plasma with externally imposed radial electric fields

    Science.gov (United States)

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

    1979-01-01

    Strong electric fields were imposed along the minor radius of the toroidal plasma by biasing it with electrodes maintained at kilovolt potentials. Coherent, low-frequency disturbances characteristic of various magnetohydrodynamic instabilities were absent in the high-density, well-confined regime. High, direct-current radial electric fields with magnitudes up to 135 volts per centimeter penetrated inward to at least one-half the plasma radius. When the electric field pointed radially toward, the ion transport was inward against a strong local density gradient; and the plasma density and confinement time were significantly enhanced. The radial transport along the electric field appeared to be consistent with fluctuation-induced transport. With negative electrode polarity the particle confinement was consistent with a balance of two processes: a radial infusion of ions, in those sectors of the plasma not containing electrodes, that resulted from the radially inward fields; and ion losses to the electrodes, each of the which acted as a sink and drew ions out of the plasma. A simple model of particle confinement was proposed in which the particle confinement time is proportional to the plasma volume. The scaling predicted by this model was consistent with experimental measurements.

  20. Control of radial electric field in torus plasma

    International Nuclear Information System (INIS)

    Ida, K.; Idei, H.; Sanuki, H.

    1994-09-01

    The radial electric fields is controlled by changing the direction of neutral beam from co to counter to plasma current in tokamak, while it is controlled by the 2nd harmonic ECH and NBI and pellet injection in heliotron/torsatron. (author)

  1. Core radial electric field and transport in Wendelstein 7-X plasmas

    Science.gov (United States)

    Pablant, N. A.; Langenberg, A.; Alonso, A.; Beidler, C. D.; Bitter, M.; Bozhenkov, S.; Burhenn, R.; Beurskens, M.; Delgado-Aparicio, L.; Dinklage, A.; Fuchert, G.; Gates, D.; Geiger, J.; Hill, K. W.; Höfel, U.; Hirsch, M.; Knauer, J.; Krämer-Flecken, A.; Landreman, M.; Lazerson, S.; Maaßberg, H.; Marchuk, O.; Massidda, S.; Neilson, G. H.; Pasch, E.; Satake, S.; Svennson, J.; Traverso, P.; Turkin, Y.; Valson, P.; Velasco, J. L.; Weir, G.; Windisch, T.; Wolf, R. C.; Yokoyama, M.; Zhang, D.; W7-X Team

    2018-02-01

    The results from the investigation of neoclassical core transport and the role of the radial electric field profile (Er) in the first operational phase of the Wendelstein 7-X (W7-X) stellarator are presented. In stellarator plasmas, the details of the Er profile are expected to have a strong effect on both the particle and heat fluxes. Investigation of the radial electric field is important in understanding neoclassical transport and in validation of neoclassical calculations. The radial electric field is closely related to the perpendicular plasma flow (u⊥) through the force balance equation. This allows the radial electric field to be inferred from measurements of the perpendicular flow velocity, which can be measured using the x-ray imaging crystal spectrometer and correlation reflectometry diagnostics. Large changes in the perpendicular rotation, on the order of Δu⊥˜ 5 km/s (ΔEr ˜ 12 kV/m), have been observed within a set of experiments where the heating power was stepped down from 2 MW to 0.6 MW. These experiments are examined in detail to explore the relationship between heating power temperature, and density profiles and the radial electric field. Finally, the inferred Er profiles are compared to initial neoclassical calculations based on measured plasma profiles. The results from several neoclassical codes, sfincs, fortec-3d, and dkes, are compared both with each other and the measurements. These comparisons show good agreement, giving confidence in the applicability of the neoclassical calculations to the W7-X configuration.

  2. Neoclassical transport and radial electric fields in TJ-K

    International Nuclear Information System (INIS)

    Rahbarnia, K.; Greiner, F.; Ramisch, M.; Stroth, U.; Greiner, F.

    2003-01-01

    The neoclassical transport is investigated in the torsatron TJ-K, which is operated with a low-temperature plasma. In the low-collisionality regime neoclassical losses are not intrinsically ambipolar, leading to the formation of a radial electric field which acts on both neoclassical and turbulent transport. This electric field is measured with a combination of Langmuir and emissive probes. The data are compared with the ambipolar electric field calculated with an analytic model. The experimental fields are positive and larger than the calculated ones. Direct losses of the fast electrons might explain this discrepancy. (orig.)

  3. Modelling of radial electric field profile for different divertor configurations

    International Nuclear Information System (INIS)

    Rozhansky, V; Kaveeva, E; Voskoboynikov, S; Counsell, G; Kirk, A; Meyer, H; Coster, D; Conway, G; Schirmer, J; Schneider, R

    2006-01-01

    The impact of divertor configuration on the structure of the radial electric field has been simulated by the B2SOLPS5.0 transport fluid code. It is shown that the change in the parallel flows in the scrape-off layer, which are transported through the separatrix due to turbulent viscosity and diffusivity, should result in variation of the radial electric field and toroidal rotation in the separatrix vicinity. The modelling predictions are compared with the measurements of the radial electric field for the low field side equatorial mid-plane of ASDEX Upgrade in lower, upper and double-null (DN) divertor configurations. The parallel (toroidal) flows in the scrape-off layer and mechanisms for their formation are analysed for different geometries. It is demonstrated that a spike in the electric field exists at the high field side equatorial mid-plane in the connected DN divertor configuration. Its origin is connected with different potential drops between the separatrix vicinity and divertor plates in the two disconnected scrape-off layers, while the separatrix should be at almost the same potential. The spike might be important for additional turbulent suppression

  4. Radial electric field evolution in various operational modes in the TUMAN-3M tokamak

    International Nuclear Information System (INIS)

    Askinazi, L G; Kornev, V A; Krikunov, S V; Lebedev, S V; Smirnov, A I; Tukachinsky, A S; Vildjunas, M I; Zhubr, N A; Krupnik, L I; Tendler, M

    2008-01-01

    Radial electric field evolution has been studied on the TUAMN-3M tokamak in different modes of operation: ohmic and NBI heating, L- and H-modes, with and without strong MHD activity. Peripheral radial electric field was measured using Langmuire probes, which were inserted up to 2cm inside LCFS, while core plasma potential evolution was measured using HIBP diagnostic. It was found, that in presence of strong MHD activity radial electric field in a vicinity of the island changed sign from negative to positive and could reach up to 4kV/m. Central plasma potential exhibited a positive perturbation of ∼700V during the MHD burst. This positive radial electric field might lead to H-mode termination, both in ohmic and NBI heating cases. Possible mechanism of the positive E r generation, namely the electron losses along ergodized magnetic field lines in the presence of MHD-island, is discussed. The same mechanism might be responsible for the positive potential spikes during a saw-tooth crash, also observed using HIBP. Another phenomenon observed using HIBP was quasi-coherent potential oscillations with the frequency close to one of the GAM. Possible location of these oscillations in the core region r/a ∼ 0.33 is discussed

  5. Effects of radial electrical field on neoclassical transport in tokamaks

    International Nuclear Information System (INIS)

    Wang Zhongtian; Le Clair, G.

    1996-07-01

    Neoclassical transport theory for tokamaks in presence of a radial electrical field with shear is developed using Hamiltonian formalism. Diffusion coefficients are derived in both plateau regime including a large electric field and banana regime including the squeezing factor which can greatly affect diffusion at the plasma edge. The scaling on squeezing factor is different from the one given by Shaing and Hazeltine. Rotation speeds are calculated in the scrape-off region. They are in good agreement with measurements on TdeV Tokamak. (2 figs.)

  6. Confinement in W7-AS and the role of radial electric field and magnetic shear

    International Nuclear Information System (INIS)

    Brakel, R.; Anton, M.; Baldzuhn, J.; Burhenn, R.; Erckmann, V.; Fiedler, S.; Geiger, J.; Hartfuss, H.J.; Heinrich, O.; Hirsch, M.; Jaenicke, R.; Kick, M.; Kuehner, G.; Maassberg, H.; Stroth, U.; Wagner, F.; Weller, A.

    1997-01-01

    Improved neoclassical electron confinement in the centre of low-density ECRH plasmas has been observed in the presence of a strong positive radial electric field, which resembles the electron root solution of the neoclassical ambipolarity condition but is obviously driven by the loss of ECRH-generated suprathermal electrons. At higher densities and with NBI heating, a high confinement regime substantially above the ISS95-scaling and different from the H-mode is established with a strongly sheared negative radial electric field at the boundary. The application of plasma-current induced magnetic shear reveals that confinement in W7-AS is essentially determined by perturbations at high-order rational surfaces. For optimum confinement, these resonances have either to be avoided in the boundary region or magnetic shear must be sufficiently large. Independent of its sign, magnetic shear can reduce electron energy transport which is enhanced in the presence of such resonances to the neoclassical level. (author)

  7. Strong economic growth driving increased electricity consumption

    International Nuclear Information System (INIS)

    Tiusanen, P.

    2000-01-01

    The Finnish economy is growing faster today than anyone dared hope only a few years ago. Growth estimates for 2000 have already had to be raised. This strong level of economic growth has been reflected in electricity consumption, which has continued to increase, despite the exceptionally warm winter. A major part of this increased electricity usage has so far been met through imports. The continued growth in electricity imports has largely been a result of the fact that the good water level situation in Sweden and Norway, together with the mild winter, has kept electricity prices exceptionally low on the Nordic electricity exchange. The short period of low temperatures seen at the end of January showed, however, that this type of temperature fluctuation, combined with the restrictions that exist in regard to transfer capacity, can serve to push Nordic exchange electricity prices to record levels. This increase in price also highlights the fact that we are approaching a situation in which capacity will be insufficient to meet demand. A truly tough winter has not been seen since the Nordic region's electricity markets were deregulated. The lesson that needs to be learnt is that Finland needs sufficient capacity of her own to meet demand even during particularly cold winters. Finland used 77.9 billion kWh of electricity last year, up 1.6% or 1.3 billion kWh on 1998. This growth was relatively evenly distributed among different user groups. This year, electricity consumption is forecast to grow by 2-3%

  8. Transport modelling including radial electric field and plasma rotation

    International Nuclear Information System (INIS)

    Fukuyama, A.; Fuji, Y.; Itoh, S.-I.

    1994-01-01

    Using a simple turbulent transport model with a constant diffusion coefficient and a fixed temperature profile, the density profile in a steady state and the transient behaviour during the co and counter neutral beam injection are studied. More consistent analysis has been initiated with a turbulent transport model based on the current diffusive high-n ballooning mode. The enhancement of the radial electric field due to ion orbit losses and the reduction of the transport due to the poloidal rotation shear are demonstrated. The preliminary calculation indicates a sensitive temperature dependence of the density profile. (author)

  9. Transport analysis of radial electric field in helical plasmas

    International Nuclear Information System (INIS)

    Toda, S.; Itoh, K.

    2004-01-01

    A set of transport equations is analyzed which induces the radial transition of the electric field. A temperature profile which is related with the transport barrier is obtained by use of the theoretical model for the anomalous transport diffusivities. A dependence on the different initial condition is found even if the same values of the control parameters are used in calculations. A study of the temporal evolution of E r is done. We examine the test of the adopted theoretical model for the anomalous transport diffusivities compared with the experimental result in Large Helical Device (LHD). (authors)

  10. Sparse Reconstruction of Electric Fields from Radial Magnetic Data

    International Nuclear Information System (INIS)

    Yeates, Anthony R.

    2017-01-01

    Accurate estimates of the horizontal electric field on the Sun’s visible surface are important not only for estimating the Poynting flux of magnetic energy into the corona but also for driving time-dependent magnetohydrodynamic models of the corona. In this paper, a method is developed for estimating the horizontal electric field from a sequence of radial-component magnetic field maps. This problem of inverting Faraday’s law has no unique solution. Unfortunately, the simplest solution (a divergence-free electric field) is not realistically localized in regions of nonzero magnetic field, as would be expected from Ohm’s law. Our new method generates instead a localized solution, using a basis pursuit algorithm to find a sparse solution for the electric field. The method is shown to perform well on test cases where the input magnetic maps are flux balanced in both Cartesian and spherical geometries. However, we show that if the input maps have a significant imbalance of flux—usually arising from data assimilation—then it is not possible to find a localized, realistic, electric field solution. This is the main obstacle to driving coronal models from time sequences of solar surface magnetic maps.

  11. Sparse Reconstruction of Electric Fields from Radial Magnetic Data

    Energy Technology Data Exchange (ETDEWEB)

    Yeates, Anthony R. [Department of Mathematical Sciences, Durham University, Durham, DH1 3LE (United Kingdom)

    2017-02-10

    Accurate estimates of the horizontal electric field on the Sun’s visible surface are important not only for estimating the Poynting flux of magnetic energy into the corona but also for driving time-dependent magnetohydrodynamic models of the corona. In this paper, a method is developed for estimating the horizontal electric field from a sequence of radial-component magnetic field maps. This problem of inverting Faraday’s law has no unique solution. Unfortunately, the simplest solution (a divergence-free electric field) is not realistically localized in regions of nonzero magnetic field, as would be expected from Ohm’s law. Our new method generates instead a localized solution, using a basis pursuit algorithm to find a sparse solution for the electric field. The method is shown to perform well on test cases where the input magnetic maps are flux balanced in both Cartesian and spherical geometries. However, we show that if the input maps have a significant imbalance of flux—usually arising from data assimilation—then it is not possible to find a localized, realistic, electric field solution. This is the main obstacle to driving coronal models from time sequences of solar surface magnetic maps.

  12. Pentacene Excitons in Strong Electric Fields.

    Science.gov (United States)

    Kuhnke, Klaus; Turkowski, Volodymyr; Kabakchiev, Alexander; Lutz, Theresa; Rahman, Talat S; Kern, Klaus

    2018-02-05

    Electroluminescence spectroscopy of organic semiconductors in the junction of a scanning tunneling microscope (STM) provides access to the polarizability of neutral excited states in a well-characterized molecular geometry. We study the Stark shift of the self-trapped lowest singlet exciton at 1.6 eV in a pentacene nanocrystal. Combination of density functional theory (DFT) and time-dependent DFT (TDDFT) with experiment allows for assignment of the observation to a charge-transfer (CT) exciton. Its charge separation is perpendicular to the applied field, as the measured polarizability is moderate and the electric field in the STM junction is strong enough to dissociate a CT exciton polarized parallel to the applied field. The calculated electric-field-induced anisotropy of the exciton potential energy surface will also be of relevance to photovoltaic applications. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Overview on the radial electric field, plasma rotation and transport in the stellarator W7-AS

    International Nuclear Information System (INIS)

    Baldzuhn, J.; Kick, M.; Maassberg, H.; Ohlendorf, W.

    1998-01-01

    In the advanced stellarator W7-AS the radial electric field E r is measured by active charge exchange recombination spectroscopy CXRS. In parallel, it is calculated by using the neoclassical DKES code. A comparison of calculated and measured solutions reveals in how far the neoclassical model is valid for the description of the radial particle transport and the formation of E r . In general good consistency is found, even for the outer radii where the neoclassical fluxes become much smaller than the experimental ones. In this paper the interplay between the particular E r roots and transport is considered. For strongly positive E r a reduction of χ e is observed in the vicinity of the magnetic axis. The typically negative ion-root in the gradient region strongly influences the local ∇ T i , thus determining the maximum attainable T i (0). (author)

  14. Plasma rotation and radial electric field with a density ramp in an ohmically heated tokamak

    International Nuclear Information System (INIS)

    Duval, B.P.; Joye, B.; Marchal, B.

    1991-10-01

    Measurements of toroidal and poloidal rotation of the TCA plasma with Alfven Wave Heating and different levels of gas feed are reported. The temporal evolution of the rotation was inferred from intrinsic spectral lines of CV, CIII and, using injected helium gas, from HeII. The light collection optics and line intensity permitted the evolution of the plasma rotation to be measured with a time resolution of 2ms. The rotation velocities were used to deduce the radial electric field. With Alfven heating there was no observable change of this electric field that could have been responsible for the density rise which is characteristic of the RF experiments on TCA. The behaviour of the plasma rotation with different plasma density ramp rates was investigated. The toroidal rotation was observed to decrease with increasing plasma density. The poloidal rotation was observed to follow the value of the plasma density. With hard gas puffing, changes in the deduced radial electric field were found to coincide with changes in the peaking of the plasma density profile. Finally, with frozen pellet injection, the expected increase in the radial electric field due to the increased plasma density was not observed, which may explain the poorer confinement of the injected particles. Even in an ohmically heated tokamak, the measurement of the plasma rotation and the radial electric field are shown to be strongly related to the confinement. A thorough statistical analysis of the systematic errors is presented and a new and significant source of uncertainty in the experimental technique is identified. (author) 18 figs., 18 refs

  15. Effects of the radial electric field in a quasisymmetric stellarator

    International Nuclear Information System (INIS)

    Landreman, Matt; Catto, Peter J

    2011-01-01

    Recent calculations have shown that a radial electric field can significantly alter the neoclassical ion heat flux, ion flow, bootstrap current and residual zonal flow in a tokamak, even when the E x B drift is much smaller than the ion thermal speed. Here we show the novel analytical methods used in these calculations can be adapted to a quasisymmetric stellarator. The methods are based on using the conserved helical momentum ψ * instead of the poloidal or toroidal flux as a radial coordinate in the kinetic equation. The banana-regime calculations also employ a model collision operator that keeps only the velocity-space derivatives normal to the trapped-passing boundary, even as this boundary is shifted and deformed by the E x B drift. We prove the isomorphism between quasisymmetric stellarators and tokamaks extends to the finite-E x B generalizations of both banana-regime and plateau-regime neoclassical theory and the residual zonal flow. The plateau-regime results may be relevant to the HSX stellarator, and both the plateau- and banana-regime results can be used to validate stellarator transport codes.

  16. Analysis of radial electric field in LHD towards improved confinement

    International Nuclear Information System (INIS)

    Yokoyama, M.; Ida, K.; Sanuki, H.; Itoh, K.; Narihara, K.; Tanaka, K.; Kawahata, K.; Ohyabu, N.

    2001-05-01

    The radial electric field (E r ) properties in LHD have been investigated to indicate the guidance towards improved confinement with possible E r transition and bifurcation. The ambipolar E r is obtained from the neoclassical flux based on the analytical formulae. This approach is appropriate to clarify ambipolar E r properties in a wide range of temperature and density in a more transparent way. The comparison between calculated E r and experimentally measured one has shown the qualitatively good agreement such as the threshold density for the transition from ion root to electron root. The calculations also well reproduce the experimentally observed tendency that the electron root is possible by increasing temperatures even for higher density and the ion root is enhanced for higher density. Based on the usefulness of this approach to analyze E r in LHD, calculations in a wide range have been performed to clarify the parameter region of interest where multiple solutions of E r can exist. This is the region where E r transition and bifurcation may be realized as already experimentally confirmed in CHS. The systematic calculations give a comprehensive understandings of experimentally observed E r properties, which indicates an optimum path towards improved confinement. (author)

  17. Strong non-radial propagation of energetic electrons in solar corona

    Science.gov (United States)

    Klassen, A.; Dresing, N.; Gómez-Herrero, R.; Heber, B.; Veronig, A.

    2018-06-01

    Analyzing the sequence of solar energetic electron events measured at both STEREO-A (STA) and STEREO-B (STB) spacecraft during 17-21 July 2014, when their orbital separation was 34°, we found evidence of a strong non-radial electron propagation in the solar corona below the solar wind source surface. The impulsive electron events were associated with recurrent flare and jet (hereafter flare/jet) activity at the border of an isolated coronal hole situated close to the solar equator. We have focused our study on the solar energetic particle (SEP) event on 17 July 2014, during which both spacecraft detected a similar impulsive and anisotropic energetic electron event suggesting optimal connection of both spacecraft to the parent particle source, despite the large angular separation between the parent flare and the nominal magnetic footpoints on the source surface of STA and STB of 68° and 90°, respectively. Combining the remote-sensing extreme ultraviolet (EUV) observations, in-situ plasma, magnetic field, and energetic particle data we investigated and discuss here the origin and the propagation trajectory of energetic electrons in the solar corona. We find that the energetic electrons in the energy range of 55-195 keV together with the associated EUV jet were injected from the flare site toward the spacecraft's magnetic footpoints and propagate along a strongly non-radial and inclined magnetic field below the source surface. From stereoscopic (EUV) observations we estimated the inclination angle of the jet trajectory and the respective magnetic field of 63° ± 11° relative to the radial direction. We show how the flare accelerated electrons reach very distant longitudes in the heliosphere, when the spacecraft are nominally not connected to the particle source. This example illustrates how ballistic backmapping can occasionally fail to characterize the magnetic connectivity during SEP events. This finding also provides an additional mechanism (one among others

  18. Neoclassical transport, poloidal rotation and radial electric field at the L-H transition

    International Nuclear Information System (INIS)

    Minardi, E.; Gervasini, G.; Lazzaro, E.

    1993-01-01

    The transition to a high confinement regime in tokamaks operating with a magnetic divertor configuration is accompanied by the strong steepening of the edge temperature profile and the onset of a large positive poloidal mass rotation associated with a negative radial electric field. The latter phenomena are signatures of a neoclassical transport mechanism. We address the question of establishing whether neoclassical transport is indeed sufficient to establish high edge gradients and drive poloidal rotation under strong auxiliary heating. The heat transport equation is solved numerically in a narrow edge layer interfaced to the plasma body through heat flux continuity, but allowing for heat conductivity discontinuity. The results compared with recent experimental measurements support the assumption that a highly sheared neoclassical poloidal velocity profile can suppress the anomalous part of the heat transport, and that the neoclassical residual transport, characterizes the plasma behaviour at the edge during H modes. (author) 3 refs., 4 figs

  19. Dependence of the trapping regions with the radial electric field in TJ-II

    International Nuclear Information System (INIS)

    Guasp, J.; Liniers, M.

    1997-01-01

    The influence of the electric field upon the radial and angular distributions of trapped ions of energies between 0.1 and 1 keV in TJ-II is analysed. Near the magnetic axis, with moderate electric fields, the trapped fraction increases for negative potentials and decreases for positive ones. Nevertheless for high potentials this decreasing for positive sign can be reversed. Near the plasma periphery trapping is affected only for high potentials and always increases, independently of the potential sign. The sensibility to negative potentials is always higher than for the positive ones. These trapping changes are almost uniform in poloidal and toroidal angular profiles and affect mainly to marginally trapped or passing particles. Nevertheless for high potentials or energie the resonances modify this behaviour and inhibit the increasing of trapping in the outer side or the torus. For the locally trapped population fraction a steady decrease with the potential appears independently of the sign, except very near the magnetic axis or the plasma periphery. The global result of all these partial effects is the presence of a wide trapping minimum for moderate positive electric potential, potential that increases with the ion energy as well as a strong increase for high electric fields of either sign, more visible for negative potentials and high energies. For the locally trapped population a steady decrease with potential appears independently of the sign. All these effects can be explained by the combined action of the appearance and elimination of radial magnetic barriers and of the electric field resonances. (Author)

  20. radial

    Directory of Open Access Journals (Sweden)

    JOHN WILLIAM BRANCH

    2007-01-01

    Full Text Available La creación de modelos de objetos reales es una tarea compleja para la cual se ha visto que el uso de técnicas tradicionales de modelamiento tiene restricciones. Para resolver algunos de estos problemas, los sensores de rango basados en láser se usan con frecuencia para muestrear la superficie de un objeto desde varios puntos de vista, lo que resulta en un conjunto de imágenes de rango que son registradas e integradas en un modelo final triangulado. En la práctica, debido a las propiedades reflectivas de la superficie, las oclusiones, y limitaciones de acceso, ciertas áreas de la superficie del objeto usualmente no son muestreadas, dejando huecos que pueden crear efectos indeseables en el modelo integrado. En este trabajo, presentamos un nuevo algoritmo para el llenado de huecos a partir de modelos triangulados. El algoritmo comienza localizando la frontera de las regiones donde están los huecos. Un hueco consiste de un camino cerrado de bordes de los triángulos en la frontera que tienen al menos un borde que no es compartido con ningún otro triangulo. El borde del hueco es entonces adaptado mediante un B-Spline donde la variación promedio de la torsión del la aproximación del B-spline es calculada. Utilizando un simple umbral de la variación promedio a lo largo del borde, se puede clasificar automáticamente, entre huecos reales o generados por intervención humana. Siguiendo este proceso de clasificación, se usa entonces una versión automatizada del interpolador de funciones de base radial para llenar el interior del hueco usando los bordes vecinos.

  1. Anelastic spherical dynamos with radially variable electrical conductivity

    Science.gov (United States)

    Dietrich, W.; Jones, C. A.

    2018-05-01

    A series of numerical simulations of the dynamo process operating inside gas giant planets has been performed. We use an anelastic, fully nonlinear, three-dimensional, benchmarked MHD code to evolve the flow, entropy and magnetic field. Our models take into account the varying electrical conductivity, high in the ionised metallic hydrogen region, low in the molecular outer region. Our suite of electrical conductivity profiles ranges from Jupiter-like, where the outer hydrodynamic region is quite thin, to Saturn-like, where there is a thick non-conducting shell. The rapid rotation leads to the formation of two distinct dynamical regimes which are separated by a magnetic tangent cylinder - mTC. Outside the mTC there are strong zonal flows, where Reynolds stress balances turbulent viscosity, but inside the mTC Lorentz force reduces the zonal flow. The dynamic interaction between both regions induces meridional circulation. We find a rich diversity of magnetic field morphologies. There are Jupiter-like steady dipolar fields, and a belt of quadrupolar dominated dynamos spanning the range of models between Jupiter-like and Saturn-like conductivity profiles. This diversity may be linked to the appearance of reversed sign helicity in the metallic regions of our dynamos. With Saturn-like conductivity profiles we find models with dipolar magnetic fields, whose axisymmetric components resemble those of Saturn, and which oscillate on a very long time-scale. However, the non-axisymmetric field components of our models are at least ten times larger than those of Saturn, possibly due to the absence of any stably stratified layer.

  2. Radial electric field and transport near the rational surface and the magnetic island in LHD

    International Nuclear Information System (INIS)

    Ida, K.; Inagaki, S.; Tamura, N.

    2002-10-01

    The structure of the radial electric field and heat transport at the magnetic island in the Large Helical Device is investigated by measuring the radial profile of poloidal flow with charge exchange spectroscopy. The convective poloidal flow inside the island is observed when the n/m=1/1 external perturbation field becomes large enough to increase the magnetic island width above a critical value (15-20% of minor radius) in LHD. This convective poloidal flow results in a non-flat space potential inside the magnetic island. The sign of the curvature of the space potential depends on the radial electric field at the boundary of the magnetic island. The heat transport inside the magnetic island is studied with a cold pulse propagation technique. The experimental results show the existence of the radial electric field shear at the boundary of the magnetic island and a reduction of heat transport inside the magnetic island. (author)

  3. On improved confinement in mirror plasmas by a radial electric field

    Science.gov (United States)

    Ågren, O.; Moiseenko, V. E.

    2017-11-01

    A weak radial electric field can suppress radial excursions of a guiding center from its mean magnetic surface. The physical origin of this effect is the smearing action by a poloidal E × B rotation, which tend to cancel out the inward and outward radial drifts. A use of this phenomenon may provide larger margins for magnetic field shaping with radial confinement of particles maintained in the collision free idealization. Mirror fields, stabilized by a quadrupolar field component, are of particular interest for their MHD stability and the possibility to control the quasi neutral radial electric field by biased potential plates outside the confinement region. Flux surface footprints on the end tank wall have to be traced to avoid short-circuiting between biased plates. Assuming a robust biasing procedure, moderate voltage demands for the biased plates seems adequate to cure even the radial excursions of Yushmanov ions which could be locally trapped near the mirrors. Analytical expressions are obtained for a magnetic quadrupolar mirror configuration which possesses minimal radial magnetic drifts in the central confinement region. By adding a weak controlled radial quasi-neutral electric field, the majority of gyro centers are predicted to be forced to move even closer to their respective mean magnetic surface. The gyro center radial coordinate is in such a case an accurate approximation for a constant of motion. By using this constant of motion, the analysis is in a Vlasov description extended to finite β. A correspondence between that Vlasov system and a fluid description with a scalar pressure and an electric potential is verified. The minimum B criterion is considered and implications for flute mode stability in the considered magnetic field is analyzed. By carrying out a long-thin expansion to a higher order, the validity of the calculations are extended to shorter and more compact device designs.

  4. Structure of the radial electric field and toroidal/poloidal flow in high temperature toroidal plasma

    International Nuclear Information System (INIS)

    Ida, Katsumi

    2001-01-01

    The structure of the radial electric field and toroidal/poloidal flow is discussed for the high temperature plasma in toroidal systems, tokamak and Heliotron type magnetic configurations. The spontaneous toroidal and poloidal flows are observed in the plasma with improved confinement. The radial electric field is mainly determined by the poloidal flow, because the contribution of toroidal flow to the radial electric field is small. The jump of radial electric field and poloidal flow are commonly observed near the plasma edge in the so-called high confinement mode (H-mode) plasmas in tokamaks and electron root plasma in stellarators including Heliotrons. In general the toroidal flow is driven by the momentum input from neutral beam injected toroidally. There is toroidal flow not driven by neutral beam in the plasma and it will be more significant in the plasma with large electric field. The direction of these spontaneous toroidal flows depends on the symmetry of magnetic field. The spontaneous toroidal flow driven by the ion temperature gradient is in the direction to increase the negative radial electric field in tokamak. The direction of spontaneous toroidal flow in Heliotron plasmas is opposite to that in tokamak plasma because of the helicity of symmetry of the magnetic field configuration. (author)

  5. Radial electric field studies in the plasma edge of ASDEX upgrade

    International Nuclear Information System (INIS)

    Viezzer, Eleonora

    2012-01-01

    In magnetically confined fusion plasmas, edge transport barriers (ETBs) are formed during the transition from a highly turbulent state (low confinement regime, L-mode) to a high energy confinement regime (H-mode) with reduced turbulence and transport. The performance of an H-mode fusion plasma is highly dependent on the strength of the ETB which extends typically over the outermost 5% of the confined plasma. The formation of the ETB is strongly connected to the existence of a sheared plasma flow perpendicular to the magnetic field caused by a local radial electric field E r . The gradients in E r and the accompanying E x B velocity shear play a fundamental role in edge turbulence suppression, transport barrier formation and the transition to H-mode. Thus, the interplay between macroscopic flows and transport at the plasma edge is of crucial importance to understanding plasma confinement and stability. The work presented in this thesis is based on charge exchange recombination spectroscopy (CXRS) measurements performed at the plasma edge of the ASDEX Upgrade (AUG) tokamak. During this thesis new high-resolution CXRS diagnostics were installed at the outboard and inboard miplane of AUG, which provide measurements of the temperature, density and flows of the observed species. From these measurements the radial electric field can be directly determined via the radial force balance equation. The new CXRS measurements, combined with the other edge diagnostics available at AUG, allow for an unprecedented, high-accuracy localization (2-3 mm) of the E r profile. The radial electric field has been derived from charge exchange spectra measured on different impurity species including He 2+ , B 5+ , C 6+ and Ne 10+ . The resulting E r profiles are found to be identical within the uncertainties regardless of the impurity species used, thus demonstrating the validity of the diagnostic technique. Inside the ETB the E r profile forms a deep, negative (i.e. directed towards the

  6. Confinement of ripple-trapped slowing-down ions by a radial electric field

    International Nuclear Information System (INIS)

    Herrmann, W.

    1998-03-01

    Weakly collisional ions trapped in the toroidal field ripples at the outer plasma edge can be prevented to escape the plasma due to grad B-drift by a counteracting radial electric field. This leads to an increase in the density of ripple-trapped ions, which can be monitored by the analysis of charge exchange neutrals. The minimum radial electric field E r necessary to confine ions with energy E and charge q (q=-1: charge of the electron) is E r = -E/(q * R), where R is the major radius at the measuring point. Slowing-down ions from neutral injection are usually in the right energy range to be sufficiently collisionless in the plasma edge and show the confinement by radial electric fields in the range of tens of kV/m. The density of banana ions is almost unaffected by the radial electric field. Neither in L/H- nor in H/L-transitions does the density of ripple-trapped ions and, hence, the neutral particle fluxes, show jumps in times shorter than 1 ms. According to [1,2] the response time of the density and the fluxes to a sudden jump in the radial electric field is less than 200 μs, if the halfwidth of the electric field is larger or about 2 cm. This would exclude rapid jumps in the radial electric field at the transition. Whether the halfwidth of the electric field is that large during transition cannot be decided from the measurement of the fluxes alone. (orig.)

  7. Formation of positive radial electric field by electron cyclotron heating in compact helical system

    International Nuclear Information System (INIS)

    Idei, H.; Ida, K.; Sanuki, H.

    1994-07-01

    The radial electric field is driven to positive value by off-axis second harmonic electron cyclotron heating (ECH) in the Compact Helical System. The observed positive electric field is associated with the outward particle flux enhanced with ECH. The enhanced particle flux triggered by the production of the electrons accelerated perpendicularly to the magnetic field with ECH results in the change of the electric field. (author)

  8. Turbulence in tokamak plasmas. Effect of a radial electric field shear

    International Nuclear Information System (INIS)

    Payan, J.

    1994-05-01

    After a review of turbulence and transport phenomena in tokamak plasmas and the radial electric field shear effect in various tokamaks, experimental measurements obtained at Tore Supra by the means of the ALTAIR plasma diagnostic technique, are presented. Electronic drift waves destabilization mechanisms, which are the main features that could describe the experimentally observed microturbulence, are then examined. The effect of a radial electric field shear on electronic drift waves is then introduced, and results with ohmic heating are studied together with relations between turbulence and transport. The possible existence of ionic waves is rejected, and a spectral frequency modelization is presented, based on the existence of an electric field sheared radial profile. The position of the inversion point of this field is calculated for different values of the mean density and the plasma current, and the modelization is applied to the TEXT tokamak. The radial electric field at Tore Supra is then estimated. The effect of the ergodic divertor on turbulence and abnormal transport is then described and the density fluctuation radial profile in presence of the ergodic divertor is modelled. 80 figs., 120 refs

  9. Fast ion loss and radial electric field in high-aspect-ratio stellarator

    International Nuclear Information System (INIS)

    Itoh, Kimitaka; Sanuki, Heiji; Itoh, Sanae

    1992-01-01

    Theoretical model is developed to determine the radial electric field and the fast ion loss simultaneously in stellarators, and is applied to the Wendelstein VII-A stellarator. The predicted value of the radial electric field is more close to experiments than the purely neoclassical calculation. The loss rate, which is determined simultaneously, is in the range of experimental observations. The partition of the injection energy by the bulk heating, direct orbit loss and shine through is estimated by using the selfconsistent electric field profile. The orbit loss becomes noticeable as the injection energy increases. The influence of the neutral particles is also studied. Neutral particles enhance the negative radial electric field, and reduce the direct orbit loss by the expense of the charge exchange loss. The impact of the increased radial electric field on the neoclassical ion thermal energy loss is compared to the direct loss of fast ions. The reduction of the neoclassical loss is much smaller than the orbit loss. (author)

  10. Fast ion loss and radial electric field in Wendelstein VII-Λ stellarator

    International Nuclear Information System (INIS)

    Itoh, K.; Sanuki, H.; Itoh, S.

    1991-10-01

    Theoretical model is developed to determine the radial electric field and the fast ion loss simultaneously in stellarators, and is applied to the Wendelstein VII-A stellarator. The predicted value of the radial electric field is more closer to experiments than the purely neoclassical calculation. The loss rate, which is determined simultaneously, is in the range of experimental observations. The partition of the injection energy by the bulk heating, direct orbit loss and shine through is estimated by using the self consistent electric field profile. The orbit loss become noticeable as the injection energy increases. The influence of the neutral particles is also studied. Neutral particles enhances the negative radial electric field, and reduces the direct orbit loss by the expense of the charge exchange loss. The impact of the increased radial electric field on the neoclassical ion thermal energy loss is compared to the direct loss of fast ions. The reduction of the neoclassical loss is much smaller than the orbit loss. (author)

  11. Experimental observation of bifurcation nature of radial electric field in CHS heliotron/torsatron

    International Nuclear Information System (INIS)

    Fujisawa, Akihide; Iguchi, Harukazu; Yoshimura, Yasuo; Minami, Takashi; Tanaka, Kenji; Okamura, Shoichi; Matsuoka, Keisuke; Fujiwara, Masami

    1999-01-01

    Several interesting phenomena, such as the formation of a particular potential profile with a protuberance around the core and oscillatory stationary states termed electric pulsation, have been discovered using a heavy ion beam probe in the electron cyclotron heated plasmas of the CHS. This paper presents experimental observations which indicate that bifurcation of the radial electric field is responsible for such phenomena; existence of an ECH power threshold to obtain the profile with a protuberance, and its striking sensitivity to density. In particular, Flip-flop behavior of the potential near the power threshold clearly demonstrates bifurcation characteristics. Bifurcation of radial electric field in neoclassical theory is presented, and its qualitative expectation is discussed in the bifurcation phenomena. The neoclassical transition time scale between two bifurcative sates is compared with the experimental observations during the electric pulsation. It is confirmed that the neoclassical transition time is not contradictory with the experimental one. (author)

  12. Phase diagram of structure of radial electric field in helical plasmas

    International Nuclear Information System (INIS)

    Toda, S.; Itoh, K.

    2002-01-01

    A set of transport equations in toroidal helical plasmas is analyzed, including the bifurcation of the radial electric field. Multiple solutions of E r for the ambipolar condition induces domains of different electric polarities. A structure of the domain interface is analyzed and a phase diagram is obtained in the space of the external control parameters. The region of the reduction of the anomalous transport is identified. (author)

  13. Radial electric field in JET advanced tokamak scenarios with toroidal field ripple

    NARCIS (Netherlands)

    Crombe, K.; Andrew, Y.; Biewer, T. M.; Blanco, E.; de Vries, P. C.; Giroud, C.; Hawkes, N. C.; Meigs, A.; Tala, T.; von Hellermann, M.; Zastrow, K. D.

    2009-01-01

    A dedicated campaign has been run on JET to study the effect of toroidal field (TF) ripple on plasma performance. Radial electric field measurements from experiments on a series of plasmas with internal transport barriers (ITBs) and different levels of ripple amplitude are presented. They have been

  14. HIGHLY RESOLVED MEASUREMENTS OF PERIODIC RADIAL ELECTRIC FIELD AND ASSOCIATED RELAXATIONS IN EDGE BIASING EXPERIMENTS

    Czech Academy of Sciences Publication Activity Database

    Peleman, P.; Xu, Y.; Spolaore, M.; Brotánková, Jana; Devynck, P.; Stöckel, Jan; Van Oost, G.; Boucher, C.

    363-365, č. 17 (2007), s. 638-642 ISSN 0022-3115. [ Plasma Surface Interactions in Controlled Fusion Devices/17th./. Hefei, 22.05.2007-26.05.2007] Institutional research plan: CEZ:AV0Z20430508 Keywords : Relaxations * Edge transport * Plasma flow * Radial electric fields Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 1.643, year: 2007

  15. Electrostatic turbulence with finite parallel correlation length and radial electric field generation

    International Nuclear Information System (INIS)

    Vlad, M.; Spineanu, F.; Misguich, J.H.; Balescu, R.

    2001-01-01

    Particle diffusion in a given electrostatic turbulence with a finite correlation length along the confining magnetic field is studied in the test particle approach. An anomalous diffusion regime of amplified diffusion coefficients is found in the conditions when particle trapping in the structure of the stochastic potential is effective. The auto-generated radial electric field is calculated. (author)

  16. Ionizing gas breakdown waves in strong electric fields.

    Science.gov (United States)

    Klingbeil, R.; Tidman, D. A.; Fernsler, R. F.

    1972-01-01

    A previous analysis by Albright and Tidman (1972) of the structure of an ionizing potential wave driven through a dense gas by a strong electric field is extended to include atomic structure details of the background atoms and radiative effects, especially, photoionization. It is found that photoionization plays an important role in avalanche propagation. Velocities, electron densities, and temperatures are presented as a function of electric field for both negative and positive breakdown waves in nitrogen.

  17. Effect of radial electric field inhomogeneity on anomalous cross field plasma flux in Heliotron/Torsatron

    International Nuclear Information System (INIS)

    Yamagishi, Tomejiro; Sanuki, Heiji.

    1996-01-01

    Anomalous cross field plasma fluxes induced by the electric field fluctuations has been evaluated in a rotating plasma with shear flow in a helical system. The anomalous ion flux is evaluated by the contribution from ion curvature drift resonance continuum in the test particle model. The radial electric field induces the Doppler frequency shift which disappears in the frequency integrated anomalous flux. The inhomogeneity of the electric field (shear flow effect), however, induces a new force term in the flux. The curvature drift resonance also induces a new force term '/ which, however, did not make large influence in the ion flux in the CHS configuration. The shear flow term in the flux combined with the electric field in neoclassical flux reduces to a first order differential equation which governs the radial profile of the electric field. Numerical results indicate that the shear flow effect is important for the anomalous cross field flux and for determination of the radial electric field particularly in the peripheral region. (author)

  18. Effects of the radial electrical field on the drifts, trapping and particle orbits in TJ-II

    International Nuclear Information System (INIS)

    Guasp, J.; Liniers, M.

    1997-01-01

    In this study a detailed analysis of the effect of radial electric fields on drifts, trapping and trajectories for ions of low and intermediate energy (0.1-1 keV) in the helical axis stellarator TJ-II has been performed. In TJ-II the drift velocities have the same rotation direction than the Hard Core (HC, the same than the plasma) with predominance of the vertical downwards component. The intensity is higher near the HC and in the outwards direction. These trends create strong asymmetries in losses even in the absence of electric field. When an electric field is present the poloidal components of the drift velocity predominates modifying deeply the orbit behaviour. Positive electric fields produce internal radial trapping barriers and have a tendency to eliminate the external ones. The opposite happens for negative fields. These facts alterate deeply the tapping and confinement properties of the particles. All these analysis will be used as a basis for the understanding of the modifications on the loss distribution, trapping regions and loss cones for TJ-II that will be addressed in forthcoming studies. (Author)

  19. Possible control scenario of radial electric field by loss-cone-particle injection into helical device

    International Nuclear Information System (INIS)

    Motojima, Osamu; Shishkin, A.A.; Inagaki, Shigeru; Watanabe, Kiyomasa

    1999-08-01

    The possibility of controlling the radial electric field of toroidal plasmas by injecting high energy electrons along the reversible loss cone orbit of the helical magnetic traps is investigated. It is well known that the radial electric field plays an important role in the confinement improvement scenario especially in the low collisional regime under the physics picture of neoclassical theory. For this purpose, it is made clear that the most suitable particles are transit particles, which show a transition from helically trapped orbits to blocked ones. It is also found that a parallel AC electric field launched from outside assists this transition and makes it possible for particles to penetrate deeply into the plasma. In addition we clarify that the viscosity of the plasma coupled with the helical field configuration provide a bifurcation of plasma states and its stable solution results in confinement improvement. (author)

  20. Turbulence in tokamak plasmas. Effect of a radial electric field shear; Turbulence dans les plasmas de tokamaks. Effet d`un cisaillement de champ electrique radial

    Energy Technology Data Exchange (ETDEWEB)

    Payan, J

    1994-05-01

    After a review of turbulence and transport phenomena in tokamak plasmas and the radial electric field shear effect in various tokamaks, experimental measurements obtained at Tore Supra by the means of the ALTAIR plasma diagnostic technique, are presented. Electronic drift waves destabilization mechanisms, which are the main features that could describe the experimentally observed microturbulence, are then examined. The effect of a radial electric field shear on electronic drift waves is then introduced, and results with ohmic heating are studied together with relations between turbulence and transport. The possible existence of ionic waves is rejected, and a spectral frequency modelization is presented, based on the existence of an electric field sheared radial profile. The position of the inversion point of this field is calculated for different values of the mean density and the plasma current, and the modelization is applied to the TEXT tokamak. The radial electric field at Tore Supra is then estimated. The effect of the ergodic divertor on turbulence and abnormal transport is then described and the density fluctuation radial profile in presence of the ergodic divertor is modelled. 80 figs., 120 refs.

  1. Radial electric field studies in the plasma edge of ASDEX upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Viezzer, Eleonora

    2012-12-18

    In magnetically confined fusion plasmas, edge transport barriers (ETBs) are formed during the transition from a highly turbulent state (low confinement regime, L-mode) to a high energy confinement regime (H-mode) with reduced turbulence and transport. The performance of an H-mode fusion plasma is highly dependent on the strength of the ETB which extends typically over the outermost 5% of the confined plasma. The formation of the ETB is strongly connected to the existence of a sheared plasma flow perpendicular to the magnetic field caused by a local radial electric field E{sub r}. The gradients in E{sub r} and the accompanying E x B velocity shear play a fundamental role in edge turbulence suppression, transport barrier formation and the transition to H-mode. Thus, the interplay between macroscopic flows and transport at the plasma edge is of crucial importance to understanding plasma confinement and stability. The work presented in this thesis is based on charge exchange recombination spectroscopy (CXRS) measurements performed at the plasma edge of the ASDEX Upgrade (AUG) tokamak. During this thesis new high-resolution CXRS diagnostics were installed at the outboard and inboard miplane of AUG, which provide measurements of the temperature, density and flows of the observed species. From these measurements the radial electric field can be directly determined via the radial force balance equation. The new CXRS measurements, combined with the other edge diagnostics available at AUG, allow for an unprecedented, high-accuracy localization (2-3 mm) of the E{sub r} profile. The radial electric field has been derived from charge exchange spectra measured on different impurity species including He{sup 2+}, B{sup 5+}, C{sup 6+} and Ne{sup 10+}. The resulting E{sub r} profiles are found to be identical within the uncertainties regardless of the impurity species used, thus demonstrating the validity of the diagnostic technique. Inside the ETB the E{sub r} profile forms a deep

  2. Bifurcation of radial electric field in tokamak edge plasmas due to ion orbit loss

    International Nuclear Information System (INIS)

    Wu, G.J.; Zhang, X.D.

    2015-01-01

    The ion orbit loss and the formation of radial electric field Er in tokamak edge region are calculated. The ion orbit loss generates a negative Er, which in turn affects the ion loss. As a result, Er can saturates at either a low or a high value, depending on the plasma parameters. When the ion temperature in the plasma edge is higher than a threshold a self-sustaining growth in both the ion loss and Er is found, leading to a high saturation value of Er in the milliseconds time. This mechanism provides a possible explanation for the formation of the edge radial electric field during the L to H-mode transition observed in tokamak experiments. (author)

  3. Transitionless Enhanced Confinement and the Role of Radial Electric Field Shear

    International Nuclear Information System (INIS)

    Coppi, B.; Ernst, D.R.; Bell, M.G.; Bell, R.E.; Budny, R.V.

    1999-01-01

    Evidence for the role of radial electric field shear in enhanced confinement regimes attained without sharp bifurcations or transitions is presented. Temperature scans at constant density, created in the reheat phase following deuterium pellet injection into supershot plasmas in the Tokamak Fusion Test Reactor [J.D. Strachan, et al., Phys. Rev. Lett. 58 (1987) 1004] are simulated using a first-principles transport model. The slow reheat of the ion temperature profile, during which the temperature nearly doubles, is not explained by relatively comprehensive models of transport due to Ion Temperature Gradient Driven Turbulence (ITGDT), which depends primarily on the (unchanging) electron density gradient. An extended model, including the suppression of toroidal ITGDT by self-consistent radial electric field shear, does reproduce the reheat phase

  4. Atom-Pair Kinetics with Strong Electric-Dipole Interactions.

    Science.gov (United States)

    Thaicharoen, N; Gonçalves, L F; Raithel, G

    2016-05-27

    Rydberg-atom ensembles are switched from a weakly to a strongly interacting regime via adiabatic transformation of the atoms from an approximately nonpolar into a highly dipolar quantum state. The resultant electric dipole-dipole forces are probed using a device akin to a field ion microscope. Ion imaging and pair-correlation analysis reveal the kinetics of the interacting atoms. Dumbbell-shaped pair-correlation images demonstrate the anisotropy of the binary dipolar force. The dipolar C_{3} coefficient, derived from the time dependence of the images, agrees with the value calculated from the permanent electric-dipole moment of the atoms. The results indicate many-body dynamics akin to disorder-induced heating in strongly coupled particle systems.

  5. Effect of shear in the radial electric field on confinement in JET

    Energy Technology Data Exchange (ETDEWEB)

    O` Brien, D P; Balet, B; Deliyanakis, N; Cordey, J G; Stubberfield, P M [Commission of the European Communities, Abingdon (United Kingdom). JET Joint Undertaking

    1994-07-01

    The role of the radial electric field during enhanced confinement of JET discharges is studied. Results from two series of experiments are presented: beam dominated with the addition of a small amount of ICRH, and ICRH dominated discharges, showing that for high performance ICRH heated discharges which obtain the high confinement regime, there is evidence against the E x B flow stabilisation. 4 refs., 4 figs.

  6. Analysis of influence of the radial electric field on turbulent transport in tandem mirror plasma

    International Nuclear Information System (INIS)

    Khvesyuk, Vladimir I.; Chirkov, Alexei Yu.; Pshenichnikov, Anton A.

    2000-01-01

    The model of anomalous transport in cylindrical non-uniform steady state plasma in uniform magnetic field under the influence of many mode drift wave oscillations is suggested. The effect of anomalous transport suppression due to radial electric field is studied, and physical picture of H mode in plasma of GAMMA-10 tandem mirror device is considered. Presented theoretical and numerical results agree with the experimental data obtained on GAMMA-10. (author)

  7. The Pioneer 9 electric field experiment. III - Radial gradients and storm observations.

    Science.gov (United States)

    Scarf, F. L.; Green, I. M.; Burgess, J. S.

    1973-01-01

    We present a detailed analysis of the Pioneer 9 VLF electric field observations for 20 selected storm periods covering a heliocentric range extending from 0.754 AU to 0.99 AU. Although data from only two low frequency channels are available, the results of the present study tend to confirm the preliminary speculation by Scarf and Siscoe (1971) that the turbulent E-field spectrum in the disturbed solar wind has a significant radial gradient.

  8. Transition of radial electric field by electron cyclotron heating in stellarator plasmas

    International Nuclear Information System (INIS)

    Idei, H.; Ida, K.; Sanuki, H.

    1993-06-01

    The transition of a radial electric field from a negative to a positive value is observed in Compact Helical System when the electron loss is sufficiently enhanced by the superposition of the off-axis second harmonic electron cyclotron heating on the neutral beam heated plasmas. The observed threshold for the enhanced particle flux required to cause the transition is compared with a theoretical prediction. (author)

  9. Experiments on plasma turbulence induced by strong, steady electric fields

    International Nuclear Information System (INIS)

    Hamberger, S.M.

    1975-01-01

    The author discusses the effect of applying a strong electric field to collisionless plasma. In particular are compared what some ideas and prejudices lead one to expect to happen, what computer simulation experiments tell one ought to happen, and what actually does happen in two laboratory experiments which have been designed to allow the relevant instability and turbulent processes to occur unobstructed and which have been studied in sufficient detail. (Auth.)

  10. Finite-orbit-width effect and the radial electric field in neoclassical transport phenomena

    International Nuclear Information System (INIS)

    Satake, S.; Okamoto, M.; Nakajima, N.; Sugama, H.; Yokoyama, M.; Beidler, C.D.

    2005-01-01

    Modeling and detailed simulation of neoclassical transport phenomena both in 2D and 3D toroidal configurations are shown. The emphasis is put on the effect of finiteness of the drift-orbit width, which brings a non-local nature to neoclassical transport phenomena. Evolution of the self-consistent radial electric field in the framework of neoclassical transport is also investigated. The combination of Monte-Carlo calculation for ion transport and numerical solver of ripple-averaged kinetic equation for electrons makes it possible to calculate neoclassical fluxes and the time evolution of the radial electric field in the whole plasma region, including the finite-orbit-width (FOW) effects and global evolution of geodesic acoustic mode (GAM). The simulation results show that the heat conductivity around the magnetic axis is smaller than that obtained from standard neoclassical theory and that the evolution of GAM oscillation on each flux surface is coupled with other surfaces if the FOW effect is significant. A global simulation of radial electric field evolution in a non-axisymmetric plasma is also shown. (author)

  11. Separation of Electric Fields Into Potential and Inductive Parts, and Implications for Radial Diffusion

    Science.gov (United States)

    Chan, A. A.; Ilie, R.; Elkington, S. R.; Albert, J.; Huie, W.

    2017-12-01

    It has been traditional to separate radiation belt radial-diffusion coefficients into two contributions: an "electrostatic" diffusion coefficient, which is assumed to be due to a potential (non-inductive) electric field, and an "electromagnetic" diffusion coefficient , which is assumed to be due to the combined effect of an inductive electric field and the corresponding time-dependent magnetic field. One difficulty in implementing this separation when using magnetospheric fields obtained from measurements, or from MHD simulations, is that only the total electric field is given; the separation of the electric field into potential and inductive parts is not readily available. In this work we separate the electric field using a numerical method based on the Helmholtz decomposition of the total motional electric field calculated by the BATS-R-US MHD code. The inner boundary for the electric potential is based on the Ridley Ionospheric Model solution and we assume floating boundary conditions in the solar wind. Using different idealized solar wind drivers, including a solar wind density that is oscillating at a single frequency or with a broad spectrum of frequencies, we calculate potential and inductive electric fields, electric and magnetic power spectral densities, and corresponding radial diffusion coefficients. Simulations driven by idealized solar wind conditions show a clear separation of the potential and inductive contributions to the power spectral densities and diffusion coefficients. Simulations with more realistic solar wind drivers are underway to better assess the use of electrostatic and electromagnetic diffusion coefficients in understanding ULF wave-particle interactions in Earth's radiation belts.

  12. Fusion-product ash buildup in tokamak with radial electric field

    International Nuclear Information System (INIS)

    Downum, W.B.; Choi, C.K.; Miley, G.H.

    1979-01-01

    The buildup of thermalized fusion products (ash) in a tokamak can seriously limit burn times. Prior studies have concentrated on deposition profile effects on alpha particle transport in tokamaks but have not considered the effect on ash of radial electric fields (either created internally, e.g. due to high-energy alpha leakage, or generated externally). The present study focuses on this issue since it appears that electric fields might offer one approach to control of the ash. Approximate field and source profiles are used, based on prior calculations

  13. Model validation for radial electric field excitation during L-H transition in JFT-2M tokamak

    Science.gov (United States)

    Kobayashi, T.; Itoh, K.; Ido, T.; Kamiya, K.; Itoh, S.-I.; Miura, Y.; Nagashima, Y.; Fujisawa, A.; Inagaki, S.; Ida, K.; Hoshino, K.

    2017-07-01

    In this paper, we elaborate the electric field excitation mechanism during the L-H transition in the JFT-2M tokamak. Using time derivative of the Poisson’s equation, models of the radial electric field excitation is examined. The sum of the loss-cone loss current and the neoclassical bulk viscosity current is found to behave as the experimentally evaluated radial current that excites the radial electric field. The turbulent Reynolds stress only plays a minor role. The wave convection current that produces a negative current at the edge can be important to explain the ambipolar condition in the L-mode.

  14. Height and sex is strongly associated with radial augmentation index in Korean patients with never-treated hypertension

    Directory of Open Access Journals (Sweden)

    Ahn KT

    2016-04-01

    Full Text Available Kye Taek Ahn, Kwang-In Park, Mi Joo Kim, Jin Kyung Oh, Ji Hye Han, Hee Jin Kwon, Seon-Ah Jin, Jun-Hyung Kim, Jae-Hyeong Park, Jae-Hwan Lee, Si Wan Choi, In-Whan Seong, Jin-Ok Jeong Department of Internal Medicine, Division of Cardiology, Chungnam National University Hospital, Chungnam National University School of Medicine, Daejeon, Republic of Korea Objectives: Central hemodynamics may better represent the load imposed on the coronary and cerebral arteries and thereby bear a stronger relationship to cardiovascular outcomes. Methods: Patients who had confirmed hypertension as assessed by daytime 24-hour ambulatory blood pressure monitoring (≥135/85 mmHg were enrolled. Central blood pressure and radial augmentation index (AIx corrected for a heart rate of 75 bpm (radial AIx 75 were measured for all patients. We evaluated the association of age, height, and sex with central hemodynamics in patients with never-treated hypertension. Results: A total of 203 patients were enrolled, of whom men numbered 101 (49.7%. The median height of all patients was 162 cm, and mean age was 53.2 years. In the Pearson correlation analysis, regardless of sex difference (R=-0.627 for height, R=0.035 for age, P-value =0.005, a stronger relationship was observed between height and radial AIx 75 than between age and radial AIx 75. In the multiple regression analysis, the sex difference and height were strongly associated with elevated radial AIx 75 in all patients (adjusted R2=0.428, β=6.237, 95% confidence interval [CI] for women 1.480–10.995, P-value =0.011 and β=-0.632, 95% CI for height -0.929 to -0.335, P-value =0.009, respectively. Conclusion: In patients with never-treated hypertension, female sex and shorter height are the important risk factors of elevated radial AIx 75. Keywords: hypertension, augmentation index, height, sex

  15. A domain-decomposition method to implement electrostatic free boundary conditions in the radial direction for electric discharges

    Science.gov (United States)

    Malagón-Romero, A.; Luque, A.

    2018-04-01

    At high pressure electric discharges typically grow as thin, elongated filaments. In a numerical simulation this large aspect ratio should ideally translate into a narrow, cylindrical computational domain that envelops the discharge as closely as possible. However, the development of the discharge is driven by electrostatic interactions and, if the computational domain is not wide enough, the boundary conditions imposed to the electrostatic potential on the external boundary have a strong effect on the discharge. Most numerical codes circumvent this problem by either using a wide computational domain or by calculating the boundary conditions by integrating the Green's function of an infinite domain. Here we describe an accurate and efficient method to impose free boundary conditions in the radial direction for an elongated electric discharge. To facilitate the use of our method we provide a sample implementation. Finally, we apply the method to solve Poisson's equation in cylindrical coordinates with free boundary conditions in both radial and longitudinal directions. This case is of particular interest for the initial stages of discharges in long gaps or natural discharges in the atmosphere, where it is not practical to extend the simulation volume to be bounded by two electrodes.

  16. Radial electric field in JET advanced tokamak scenarios with toroidal field ripple

    Energy Technology Data Exchange (ETDEWEB)

    Crombe, K [Postdoctoral Fellow of the Research Foundation - Flanders (FWO), Department of Applied Physics, Ghent University, Rozier 44, B-9000 Gent (Belgium); Andrew, Y; De Vries, P C; Giroud, C; Hawkes, N C; Meigs, A; Zastrow, K-D [EURATOM/UKAEA Fusion Association, Culham Science Centre, Abingdon, Oxon, OX14 3DB (United Kingdom); Biewer, T M [Oak Ridge National Laboratory, Oak Ridge, TN 37831-6169, TN (United States); Blanco, E [Laboratorio Nacional de Fusion, Asociacion EURATOM-CIEMAT, Madrid (Spain); Tala, T [VTT Technical Research Centre of Finland, Association EURATOM-Tekes, PO Box 1000, FIN-02044 VTT (Finland); Von Hellermann, M [FOM Institute for Plasma Physics Rijnhuizen, Association EURATOM-FOM, Trilateral Euregio Cluster, PO Box 1207, 3430 BE Nieuwegein (Netherlands)], E-mail: Kristel.Crombe@jet.uk

    2009-05-15

    A dedicated campaign has been run on JET to study the effect of toroidal field (TF) ripple on plasma performance. Radial electric field measurements from experiments on a series of plasmas with internal transport barriers (ITBs) and different levels of ripple amplitude are presented. They have been calculated from charge exchange measurements of impurity ion temperature, density and rotation velocity profiles, using the force balance equation. The ion temperature and the toroidal and poloidal rotation velocities are compared in plasmas with both reversed and optimized magnetic shear profiles. Poloidal rotation velocity (v{sub {theta}}) in the ITB region is measured to be of the order of a few tens of km s{sup -1}, significantly larger than the neoclassical predictions. Increasing levels of the TF ripple are found to decrease the ion temperature gradient in the ITB region, a measure for the quality of the ITB, and the maximum value of v{sub {theta}} is reduced. The poloidal rotation term dominates in the calculations of the total radial electric field (E{sub r}), with the largest gradient in E{sub r} measured in the radial region coinciding with the ITB.

  17. An enhanced radial basis function network for short-term electricity price forecasting

    International Nuclear Information System (INIS)

    Lin, Whei-Min; Gow, Hong-Jey; Tsai, Ming-Tang

    2010-01-01

    This paper proposed a price forecasting system for electric market participants to reduce the risk of price volatility. Combining the Radial Basis Function Network (RBFN) and Orthogonal Experimental Design (OED), an Enhanced Radial Basis Function Network (ERBFN) has been proposed for the solving process. The Locational Marginal Price (LMP), system load, transmission flow and temperature of the PJM system were collected and the data clusters were embedded in the Excel Database according to the year, season, workday and weekend. With the OED applied to learning rates in the ERBFN, the forecasting error can be reduced during the training process to improve both accuracy and reliability. This would mean that even the ''spikes'' could be tracked closely. The Back-propagation Neural Network (BPN), Probability Neural Network (PNN), other algorithms, and the proposed ERBFN were all developed and compared to check the performance. Simulation results demonstrated the effectiveness of the proposed ERBFN to provide quality information in a price volatile environment. (author)

  18. Modelling of radial electric fields and currents during divertor plate biasing on TdeV

    International Nuclear Information System (INIS)

    Lachambre, J.L.; Quirion, B.; Boucher, C.

    1994-01-01

    A simple model based on non-ambipolar radial transport and planar sheath physics is used to describe the generation of radial electric fields and currents in the scrape-off layer of the Tokamak de Varennes (TdeV) during divertor plate biasing. In general, the calculated predictions compare favourably with TdeV results over a variety of plasma conditions and divertor magnetic configurations. Validated by the experiment, the model is used to study the scaling laws of perpendicular ion mobility and to test existing related theories. Finally, the model is proposed as a useful tool for the design and upgrade of biased divertors through optimization of the plate and throat geometry. (author). 35 refs, 16 figs, 1 tab

  19. Effects of the radial electric field on confinement and trapping for non collisional electrons in TJ-II

    International Nuclear Information System (INIS)

    Guasp, J.; Liniers, M.

    1998-01-01

    The effects of radial electric fields on the non collisional losses, asymmetries at plasma border and on the Vacuum Vessel and trapping fractions for 0.1 1 KeV electrons in TJ-II are analysed. This study complements a series, already published, for ions, therefore only the main differences are stressed. Many of these effect are similar for electrons and ions, mainly the drastic decrease of losses with the electric field, the increasing peripherical loss concentration, the strong accumulation on the Hard Core (HC), the modification in the direction of the induced poloidal rotation, similar angular distributions for trapped particles, etc. Nevertheless, there appear also important differences, that in many cases are originated by the higher electron mobility, in particular a higher sensitivity to the electric field, as well to the intensity as to the sign, producing a faster drop in electron losses for positive potential and a higher asymmetry in the sign dependence. Most of these electron losses exit through the upper side of the plasma, the opposite happens for ions. The strong concentration on the HC appears, many, on the PL-1 plate (the one that is placed upside for toroidal angle φ=0 degree centigree), instead of the opposite PL-2 plate for ions.Finally, for the analysed energy range, there is no variation of electron trapping with the potential nor resonant effect. (Author) 8 refs

  20. Electric conductivity of TlInTe2 monocrystal in strong electric fields

    International Nuclear Information System (INIS)

    Zarbaliev, M.M.; Godzhaev, Eh.M.; Gadzhiev, V.A.

    1980-01-01

    Electric condUctivity of the TlInTe 2 single crystal in strong electric fields has been studied in the range of 77-300 K. The electron part of the TlInTe 2 dielectric constant has been found to be 4. The dependence of the activation energy of current carriers on the electric field strength is constructed and the value of the activation energy of current carriers in the absence of an electric field is determined by the extrapolation method. The results of the experiments are in good agreement with the Frenkel-Pool theory, and this affords grounds for asserting that the obtained dependences of electric conductivity on temperature and the electric field strength are defined by variation in the current carrier concentration due to action of the thermal-electron ionization mechanism

  1. Theoretical transport analysis of density limit with radial electric field in helical plasmas

    International Nuclear Information System (INIS)

    Toda, S.; Itoh, K.

    2010-11-01

    The confinement property in helical toroidal plasmas is clarified. The analysis is performed by use of the one-dimensional transport equations with the effect of the radiative loss and the radial profile of the electric field. The analytical results in the edge region show the steep gradient in the electron temperature, which indicates the transport barrier formation. Because of the rapid increase of the radiative loss at the low electron temperature, the anomalous heat diffusivity is reduced near the edge. Next, the efficiency of the heating power input in the presence of the radiative loss is studied. The scaling of the critical density in helical devices is also derived. (author)

  2. Unifying role of radial electric field shear in the confinement trends of transitionless regimes in TFTR

    International Nuclear Information System (INIS)

    Ernst, D.R.; Beer, M.; Batha, S.

    2001-01-01

    Turbulence suppression by radial electric field shear (E r ) is shown to be important in the enhanced confinement of TFTR supershot plasmas. Simulations of supershot ion temperature profiles are performed using an existing parameterization of transport due to toroidal ion temperature gradient modes, extended to include suppression by E r shear. New spectroscopic measurements of E r differ significantly from prior neoclassical estimates. Supershot temperature profiles appear to be consistent with a criterion describing near-complete turbulence suppression by intrinsically generated E r shear. Helium spoiling and xenon puffing experiments are simulated to illustrate the role of E r shear in the confinement changes observed. (author)

  3. Unifying role of radial electric field shear in the confinement trends of transitionless regimes in TFTR

    International Nuclear Information System (INIS)

    Ernst, D.R.; Beer, M.; Batha, S.

    1999-01-01

    Turbulence suppression by radial electric field shear (E r ) is shown to be important in the enhanced confinement of TFTR supershot plasmas. Simulations of supershot ion temperature profiles are performed using an existing parameterization of transport due to toroidal ion temperature gradient modes, extended to include suppression by E r shear. New spectroscopic measurements of E r differ significantly from prior neoclassical estimates. Supershot temperature profiles appear to be consistent with a criterion describing near-complete turbulence suppression by intrinsically generated E r shear. Helium spoiling and xenon puffing experiments are simulated to illustrate the role of E r shear in the confinement changes observed. (author)

  4. Investigations of radial electric field and global circulation layer in limiter tokamaks

    International Nuclear Information System (INIS)

    Zagorski, R.; Gerhauser, H.; Lehnen, M.; Loarer, T.

    2002-01-01

    An updated version of the 2D multifluid code TECXY is used to study the radial electric field structure and the appearance of a global circulation layer (GCL) inside the separatrix of the limiter tokamaks TEXTOR-94 and Tore-Supra-CIEL. The dependence of the driving forces on device geometry, limiter position, magnetic field orientation, impurity content and other parameters is investigated. The centrifugal force in the vicinity of the limiter head always determines the direction of the poloidal velocity in the GCL. There is good agreement with experimentally measured profiles of the poloidal velocity at the TEXTOR low field side. (orig.)

  5. Ambipolarons: Solitary wave solutions for the radial electric field in a plasma

    International Nuclear Information System (INIS)

    Hastings, D.E.; Hazeltine, R.D.; Morrison, P.J.

    1986-01-01

    The ambipolar radial electric field in a nonaxisymmetric plasma can be described by a nonlinear diffusion equation. This equation is shown to possess solitary wave solutions. A model nonlinear diffusion equation with a cubic nonlinearity is studied. An explicit analytic step-like form for the solitary wave is found. It is shown that the solitary wave solutions are linearly stable against all but translational perturbations. Collisions of these solitary waves are studied and three possible final states are found: two diverging solitary waves, two stationary solitary waves, or two converging solitary waves leading to annihilation

  6. Effects of the radial electric field resonances on the particle orbits and loss cones in TJ-II

    International Nuclear Information System (INIS)

    Guasp, J.; Liniers, M.

    1997-07-01

    The effects of the radial electric field resonances on the trapping and confinement of low and intermediate energy ions (0.1-1 keV) for the Reference configuration of TJ-II have been analysed. In TJ-II these resonances appear for electric potentials that grow with pitch and with the square root of the initial kinetic energy and are placed inside strips whose width increases with the initial radius and with the absolute value of initial pitch. The 0-Resonance is the most important one for particle trapping, it appears for high electric potential (between 1000 and 3000 V for 0.5 keV ions) with the same sign than pitch, inside very wide strips (several thousands of V). Along these band periphery, for potential intensities below the central resonant values, there exists a very strong increase of particle trapping. Instead, around the resonance center, the trapping is inhibited and a very strong increase of the passing particle population appears. This increase is higher for the torus external side (Theta approximately 0 degree centigree) and for small initial radius. For peripherical particles wide loss strips appear along the border of the resonant band corresponding to more positive potential. The 2-Resonance has small effect on trapping but affects strongly to the of peripherical passing particles. It appears for moderate electric potential (between 400 and 1000 V for 0.5 keV ions) with sign opposite than pitch and inside narrow bands than the 0-Resonance. In this case a loss of peripherical passing particles appears, placed also along the more positive potential band side. The other Resonances (except the -4) have much less effect on particle trapping and confinement. All these phenomena have been explained by the action of magnetic barriers and different mechanisms for particle orbit modification. (Author) 8 refs

  7. Aqueous electrolyte surfaces in strong electric fields: molecular insight into nanoscale jets and bridges

    Science.gov (United States)

    Jirsák, Jan; Moučka, Filip; Škvor, Jiří; Nezbeda, Ivo

    2015-04-01

    Exposing aqueous surfaces to a strong electric field gives rise to interesting phenomena, such as formation of a floating water bridge or an eruption of a jet in electrospinning. In an effort to account for the phenomena at the molecular level, we performed molecular dynamics simulations using several protocols on both pure water and aqueous solutions of sodium chloride subjected to an electrostatic field. All simulations consistently point to the same mechanisms which govern the rearrangement of the originally planar surface. The results show that the phenomena are primarily governed by an orientational reordering of the water molecules driven by the applied field. It is demonstrated that, for pure water, a sufficiently strong field yields a columnar structure parallel to the field with an anisotropic arrangement of the water molecules with their dipole moments aligned along the applied field not only in the surface layer but over the entire cross section of the column. Nonetheless, the number of hydrogen bonds per molecule does not seem to be affected by the field regardless of its strength and molecule's orientation. In the electrolyte solutions, the ionic charge is able to overcome the effect of the external field tending to arrange the water molecules radially in the first coordination shell of an ion. The ion-water interaction interferes thus with the water-electric field interaction, and the competition between these two forces (i.e., strength of the field versus concentration) provides the key mechanism determining the stability of the observed structures.

  8. Effects of finite-β and radial electric fields on neoclassical transport in the Large Helical Device

    International Nuclear Information System (INIS)

    Kanno, R.; Nakajima, N.; Sugama, H.; Okamoto, M.; Ogawa, Y.

    1997-01-01

    Effects of finite-β and radial electric fields on the neoclassical transport in the Large Helical Device are investigated with the DKES (Drift Kinetic Equation Solver) code. In the finite-β configuration, even orbits of deeply trapped particles deviate significantly from magnetic flux surfaces. Thus, neoclassical ripple transport coefficients in the finite-β configuration are several times larger than those in the vacuum configuration under the same condition of temperatures and radial electric fields. When the plasma temperature is several keV, a bifurcation of the electric fields appears under the ambipolarity condition, and sufficient large radial electric fields can be generated. As a result, the ExB drift rectifies orbits of particles and improves significantly the transport coefficients in the finite-β configuration. (author)

  9. Redox processes at a nanostructured interface under strong electric fields.

    Science.gov (United States)

    Steurer, Wolfram; Surnev, Svetlozar; Netzer, Falko P; Sementa, Luca; Negreiros, Fabio R; Barcaro, Giovanni; Durante, Nicola; Fortunelli, Alessandro

    2014-09-21

    Manipulation of chemistry and film growth via external electric fields is a longstanding goal in surface science. Numerous systems have been predicted to show such effects but experimental evidence is sparse. Here we demonstrate in a custom-designed UHV apparatus that the application of spatially extended, homogeneous, very high (>1 V nm(-1)) DC-fields not only changes the system energetics but triggers dynamic processes which become important much before static contributions appreciably modify the potential energy landscape. We take a well characterized ultrathin NiO film on a Ag(100) support as a proof-of-principle test case, and show how it gets reduced to supported Ni clusters under fields exceeding the threshold of +0.9 V nm(-1). Using an effective model, we trace the observed interfacial redox process down to a dissociative electron attachment resonant mechanism. The proposed approach can be easily implemented and generally applied to a wide range of interfacial systems, thus opening new opportunities for the manipulation of film growth and reaction processes at solid surfaces under strong external fields.

  10. Lepton electric dipole moment and strong CP violation

    Science.gov (United States)

    Ghosh, Diptimoy; Sato, Ryosuke

    2018-02-01

    Contribution of the strong CP angle, θ bar , to the Wilson Coefficients of electron and muon electric dipole moment (EDM) operators are discussed. Previously, θ bar contribution to the electron EDM operator was calculated by Choi and Hong [1]. However, the effect of CP-violating three meson coupling was missing in [1]. We include this missing contribution for the first time in the literature, and reevaluate the Wilson coefficients of the lepton EDM operator. We obtain de = - (2.2 - 8.6) ×10-28 θ bar e-cm which is 15-70% of the result obtained in [1]. We also estimated the muon EDM as dμ = - (0.5 - 1.8) ×10-25 θ bar e-cm. Using | θ bar | ≲10-10 suggested by the neutron EDM measurements, we obtain |de | ≲ 8.6 ×10-38e-cm and |dμ | ≲ 1.8 ×10-35e-cm. The θ bar contribution to the muon EDM is much below the sensitivities of the current and near future experiments. Our result shows that the θ bar contribution to de,μ can be larger than the CKM contributions by many orders of magnitude.

  11. Lepton electric dipole moment and strong CP violation

    Directory of Open Access Journals (Sweden)

    Diptimoy Ghosh

    2018-02-01

    Full Text Available Contribution of the strong CP angle, θ¯, to the Wilson Coefficients of electron and muon electric dipole moment (EDM operators are discussed. Previously, θ¯ contribution to the electron EDM operator was calculated by Choi and Hong [1]. However, the effect of CP-violating three meson coupling was missing in [1]. We include this missing contribution for the first time in the literature, and reevaluate the Wilson coefficients of the lepton EDM operator. We obtain de=−(2.2–8.6×10−28θ¯e-cm which is 15–70% of the result obtained in [1]. We also estimated the muon EDM as dμ=−(0.5–1.8×10−25θ¯e-cm. Using |θ¯|≲10−10 suggested by the neutron EDM measurements, we obtain |de|≲8.6×10−38e-cm and |dμ|≲1.8×10−35e-cm. The θ¯ contribution to the muon EDM is much below the sensitivities of the current and near future experiments. Our result shows that the θ¯ contribution to de,μ can be larger than the CKM contributions by many orders of magnitude.

  12. Formation of electron-root radial electric field and its effect on thermal transport in LHD high Te plasma

    International Nuclear Information System (INIS)

    Matsuoka, Seikichi; Satake, Shinsuke; Takahashi, Hiromi; Yokoyama, Masayuki; Ido, Takeshi; Shimizu, Akihiro; Shimozuma, Takashi; Wakasa, Arimitsu; Murakami, Sadayoshi

    2013-01-01

    Neoclassical transport analyses have been performed for a high electron temperature LHD plasma with steep temperature gradient using a neoclassical transport simulation code, FORTEC-3D. It is shown that the large positive radial electric field is spontaneously formed at the core along with the increase in the electron temperature, while the neoclassical heat diffusivity remains almost unchanged. This indicates that the 1/ν-type increase expected in the neoclassical transport in helical plasmas can be avoided by the spontaneous formation of the radial electric field. At the same time, it is found that the experimentally estimated heat diffusivity is significantly reduced. This suggests that the formation process of the transport barrier in the high electron temperature plasma can be caused by the spontaneous formation of the radial electric field. (author)

  13. Radial electric field evolution in the vicinity of a rotating magnetic island in the TUMAN-3M tokamak

    International Nuclear Information System (INIS)

    Askinazi, L G; Golant, V E; Kornev, V A; Lebedev, S V; Tukachinsky, A S; Vildjunas, M I; Zhubr, N A

    2006-01-01

    Radial electric field is known to be an important factor affecting transport and confinement in toroidal fusion plasmas. Langmuire probe measurements of peripheral radial electric field evolution in the presence of a rotating MHD island were performed on the TUMAN-3M tokamak in order to clear up the possible connection between the radial electric field and the island rotation, both in L and H-modes. The measurements showed that E r became positive, if the island was large enough, in spite of the constant direction of the island's rotation. Comparing similar ohmic H-mode discharges with or without a rotating MHD island, it was found that in the presence of the large island E r was always more positive. Possible explanations of this observation are discussed

  14. Evolution of the radial electric field in a JET H-mode plasma

    International Nuclear Information System (INIS)

    Andrew, Y.; Hawkes, N.C.; Biewer, T.; Crombe, K.; Keeling, D.; De la Luna, E.; Giroud, C.; Korotkov, A.; Meigs, A.; Murari, A.; Nunes, I.; Sartori, R.; Tala, T.; Andrew, Y.; Hawkes, N.C.; Keeling, D.; Giroud, C.; Korotkov, A.; Meigs, A.; Biewer, T.; Crombe, K.; De la Luna, E.; Murari, A.; Nunes, I.; Sartori, R.; Tala, T.

    2008-01-01

    Results from recent measurements of carbon impurity ion toroidal and poloidal rotation velocities, ion temperature, ion density and the resulting radial electric field (E r ) profiles are presented from an evolving Joint European Torus (JET) tokamak plasma over a range of energy and particle confinement regimes. Significant levels of edge plasma poloidal rotation velocity have been measured for the first time on JET, with maximum values of ±9 km/s. Such values of poloidal rotation provide an important contribution to the total edge plasma E r profiles. Large values of shear in the measured E r profiles are observed to arise as a consequence of the presence of the edge transport barrier (ETB) and do not appear to be necessary for their formation or destruction. These results have an important impact on potential mechanisms for transport barrier triggering and sustainment in present-day and future high-performance fusion plasmas. (authors)

  15. Onset of the radial electric field oscillations in the neoclassical plasmas

    International Nuclear Information System (INIS)

    Liu, C.S.; Novakovskii, S.V.; Sagdeev, R.Z.; Galeev, A.A.

    1996-01-01

    It is shown that the relaxation of the radial electric field in the tokomak plasmas towards its neoclassical value is accompanied by the fast oscillations of the order of the ion transient frequency V T /qR. This happens during the transition from the Pfirsch-Schluter collisional regime to the plateau regime at v c qR/V T ≤ c cr ≤ 1. The investigation has been performed with the help of the specially developed numerical code for solution of the nonsteady-state drift kinetic equation with the exact collisional term in the Hirshman-Sigmar-Clarke form. Comparison with the analytical results, corresponding to the regime of the very low collisions as well as with previous approximate models for the plateau regime will also be reported

  16. Drift motion of a charged particle in the crossed axial magnetic and radial electric fields, and the electric field of a rotating potential wave

    International Nuclear Information System (INIS)

    Eliseev, Yu.N.; Stepanov, K.N.

    1983-01-01

    In the drift motion approximation solution of the problem is obtained on the motion of a nonrelativistic charged particle in the crossed axial magnetic and radial electric fields, and the electric field of a rotating potential wave under cherenkov and modified cyclotron resonances. The static radial electric field potential is supposed to be close to the parabolic one. The drift motion equations and their integrals are preseOted. The experimentally obtained effect of plasma ionic component division in the crossed fields under the excitation of ion cyclotron oscillations is explained with the help of the theory developed in the paper

  17. Strong CP violation and the neutron electric dipole form factor

    International Nuclear Information System (INIS)

    Kuckei, J.; Dib, C.; Faessler, A.; Gutsche, T.; Kovalenko, S. G.; Lyubovitskij, V. E.; Pumsa-ard, K.

    2007-01-01

    We calculate the neutron electric dipole form factor induced by the CP-violating θ term of QCD within a perturbative chiral quark model which includes pion and kaon clouds. On this basis, we derive the neutron electric dipole moment and the electron-neutron Schiff moment. From the existing experimental upper limits on the neutron electric dipole moment, we extract constraints on the θ parameter and compare our results with other approaches

  18. Strong electric and magnetic dipole excitations in deformed nuclei

    International Nuclear Information System (INIS)

    Kneissl, U.

    1993-01-01

    Systematic nuclear resonance fluorescence (NRF) experiments have been performed at the bremsstrahlung facility of the Stutgart dynamitron to investigate the distribution of magnetic and electric dipole excitations in deformed nuclei

  19. Optimization of confinement in a toroidal plasma subject to strong radial electric fields

    International Nuclear Information System (INIS)

    Roth, J.R.

    1977-01-01

    A preliminary report on the identification and optimization of independent variables which affect the ion density and confinement time in a bumpy torus plasma is presented. The independent variables include the polarity, position, and number of the midplane electrode rings, the method of gas injection, and the polarity and strength of a weak vertical magnetic field. Some characteristic data taken under condition when most of the independent variables were optimized are presented. The highest value of the electron number density on the plasma axis is 3.2 x 10 to the 12th power/cc, the highest ion heating efficiency is 47 percent, and the longest particle containment time is 2.0 milliseconds

  20. Development of tool for simulating the effect of radial electric fields on Ion-Temperature-Gradient modes in 3D configurations

    International Nuclear Information System (INIS)

    Eriksson, Lars

    2003-03-01

    The heat flux level observed in magnetic plasma confinement experiments such as tokamaks is much higher than what can be explained from neoclassical theory. There is a strong interest in the controlled nuclear fusion community to fully understand this phenomenon, called anomalous transport. One idea is that radial electric fields play a key role in the stabilization process of the electrostatic instabilities called micro instabilities that are considered responsible for the anomalous heat flux. This work studies the effect of a static ad-hoc radial electric field on microinstabilities, especially the ion temperature gradient (ITG) driven mode, within the frame of a global 3D gyrokinetic model. This will make it possible to extend the simulations done in tokamaks and helically symmetric systems to fully 313 magnetic configurations. Technically the work consists of extending the 3D gyrokinetic code Euterpe to also include the effect of the drifts induced by an imposed radial electrostatic potential. Simulations are performed in tokamak and helically symmetric configurations. The results indicate that this modified version of Euterpe can be used in studying more complex 3D fusion devices

  1. Strong dependence of ultracold chemical rates on electric dipole moments

    International Nuclear Information System (INIS)

    Quemener, Goulven; Bohn, John L.

    2010-01-01

    We use the quantum threshold laws combined with a classical capture model to provide an analytical estimate of the chemical quenching cross sections and rate coefficients of two colliding particles at ultralow temperatures. We apply this quantum threshold model (QT model) to indistinguishable fermionic polar molecules in an electric field. At ultracold temperatures and in weak electric fields, the cross sections and rate coefficients depend only weakly on the electric dipole moment d induced by the electric field. In stronger electric fields, the quenching processes scale as d 4(L+(1/2)) where L>0 is the orbital angular-momentum quantum number between the two colliding particles. For p-wave collisions (L=1) of indistinguishable fermionic polar molecules at ultracold temperatures, the quenching rate thus scales as d 6 . We also apply this model to pure two-dimensional collisions and find that chemical rates vanish as d -4 for ultracold indistinguishable fermions. This model provides a quick and intuitive way to estimate chemical rate coefficients of reactions occuring with high probability.

  2. Self-consistent analysis of radial electric field and fast ion losses in CHS Torsatron/Heliotron

    International Nuclear Information System (INIS)

    Sanuki, H.; Itoh, K.; Itoh, S.

    1992-09-01

    A self-consistent analysis is developed to determine the radial electric field and loss cone boundary in Torsatron/Heliotron plasmas under the influence of non-classical ion losses such as the loss cone loss ans charge exchange loss of fast ions with neutrals. Analysis is applied to the NBI heated plasmas in the Compact Helical System (CHS) device. Comparison is made between theoretical results and experimental observations. The increased ion particle losses caused by the orbit loss and charge exchange loss with neutrals make the radial electric field more negative than the value of purely neoclassical calculation. The partition of the injection energy among the shine through, direct orbit loss, change exchange loss and bulk heating is evaluated by using the self-consistent electric field profile. On-going experiments in the CHS device are briefly introduced. (author)

  3. Maximum entropy reconstruction of poloidal magnetic field and radial electric field profiles in tokamaks

    Science.gov (United States)

    Chen, Yihang; Xiao, Chijie; Yang, Xiaoyi; Wang, Tianbo; Xu, Tianchao; Yu, Yi; Xu, Min; Wang, Long; Lin, Chen; Wang, Xiaogang

    2017-10-01

    The Laser-driven Ion beam trace probe (LITP) is a new diagnostic method for measuring poloidal magnetic field (Bp) and radial electric field (Er) in tokamaks. LITP injects a laser-driven ion beam into the tokamak, and Bp and Er profiles can be reconstructed using tomography methods. A reconstruction code has been developed to validate the LITP theory, and both 2D reconstruction of Bp and simultaneous reconstruction of Bp and Er have been attained. To reconstruct from experimental data with noise, Maximum Entropy and Gaussian-Bayesian tomography methods were applied and improved according to the characteristics of the LITP problem. With these improved methods, a reconstruction error level below 15% has been attained with a data noise level of 10%. These methods will be further tested and applied in the following LITP experiments. Supported by the ITER-CHINA program 2015GB120001, CHINA MOST under 2012YQ030142 and National Natural Science Foundation Abstract of China under 11575014 and 11375053.

  4. Analysis of radial electric field bifurcation in LHD based on neoclassical transport theory

    International Nuclear Information System (INIS)

    Yokoyama, Masayuki; Ida, Katsumi; Shimozuma, Takashi

    2003-01-01

    Radial electric field (E r ) properties in LHD have been investigated based on the neoclassical transport theory and have also applied to LHD experimental results. The effects of the helicity of the magnetic configuration on the condition required to realize the electron root are examined. The larger helicity makes the threshold temperature lower for the same electron density. A higher threshold temperature is anticipated to be required in the plasma core region based on this fact and also due to the larger density there. This high electron temperature (T e ) has been successfully obtained with a center-focused ECH. There is a threshold for the ECH power to achieve a steep gradient of T e , and it seems to be qualitatively consistent with the transition of E r , at least in the sense that the abrupt increase of T e occurs after entering the anticipated electron root regime. These experimental results, consistent with those of analysis of the neoclassical ambipolar E r , indicate that the transition phenomena of E r in LHD are predominantly governed by neoclassical features. (author)

  5. The influence of the dynamic ergodic divertor on the radial electric field at the Tokamak TEXTOR

    Energy Technology Data Exchange (ETDEWEB)

    Coenen, Jan Willem

    2009-11-06

    In this work the influence of external Resonant Magnetic Perturbations (RMPs) on the radial electric field Er in magnetically confined plasmas is investigated by Charge Exchange Recombination Spectroscopy (CXRS) at the Tokamak TEXTOR. Here, the RMPs are produced with the Dynamic Ergodic Divertor (DED), a set of 16 helical perturbation coils located at the high field side of TEXTOR. Within this work, the base mode number of perturbations has been m/n=6/2. We have first investigated the influence of external torque from neutral heating beams on plasma rotation and E{sub r}. The ergodic zone causes an electron loss, and subsequently a (vector)j x (vector)B force driven by the compensating ion return current. In addition, the DED changes the global confinement properties. Depending on the edge safety factor (''field line twist'') q{sub a}, either increased or decreased particle confinement is observed. In case of the increased particle confinement (IPC) the increase in density (40%) and particle confinement time {tau}{sub p} (30%) is correlated to the connection of field lines at the q=5/2 surface to the DED target, locally changing the transport properties and the E{sub r}. Transport is reduced and the E{sub r} shear is increased locally at q=5/2 up to 1.5 . 10{sup 5}s{sup -1}, while the E{sub r} becomes more positive. (orig.)

  6. The influence of the dynamic ergodic divertor on the radial electric field at the Tokamak TEXTOR

    International Nuclear Information System (INIS)

    Coenen, Jan Willem

    2009-01-01

    In this work the influence of external Resonant Magnetic Perturbations (RMPs) on the radial electric field Er in magnetically confined plasmas is investigated by Charge Exchange Recombination Spectroscopy (CXRS) at the Tokamak TEXTOR. Here, the RMPs are produced with the Dynamic Ergodic Divertor (DED), a set of 16 helical perturbation coils located at the high field side of TEXTOR. Within this work, the base mode number of perturbations has been m/n=6/2. We have first investigated the influence of external torque from neutral heating beams on plasma rotation and E r . The ergodic zone causes an electron loss, and subsequently a vector j x vector B force driven by the compensating ion return current. In addition, the DED changes the global confinement properties. Depending on the edge safety factor (''field line twist'') q a , either increased or decreased particle confinement is observed. In case of the increased particle confinement (IPC) the increase in density (40%) and particle confinement time τ p (30%) is correlated to the connection of field lines at the q=5/2 surface to the DED target, locally changing the transport properties and the E r . Transport is reduced and the E r shear is increased locally at q=5/2 up to 1.5 . 10 5 s -1 , while the E r becomes more positive. (orig.)

  7. Electrohydrodynamics of drops in strong electric fields: Simulations and theory

    Science.gov (United States)

    Saintillan, David; Das, Debasish

    2016-11-01

    Weakly conducting dielectric liquid drops suspended in another dielectric liquid exhibit a wide range of dynamical behaviors when subject to an applied uniform electric field contingent on field strength and material properties. These phenomena are best described by the much celebrated Maylor-Taylor leaky dielectric model that hypothesizes charge accumulation on the drop-fluid interface and prescribes a balance between charge relaxation, the jump in Ohmic currents and charge convection by the interfacial fluid flow. Most previous numerical simulations based on this model have either neglected interfacial charge convection or restricted themselves to axisymmetric drops. In this work, we develop a three-dimensional boundary element method for the complete leaky dielectric model to systematically study the deformation and dynamics of liquid drops in electric fields. The inclusion of charge convection in our simulation permits us to investigate drops in the Quincke regime, in which experiments have demonstrated symmetry-breaking bifurcations leading to steady electrorotation. Our simulation results show excellent agreement with existing experimental data and small deformation theories. ACSPRF Grant 53240-ND9.

  8. Double photoexcitation of helium in a strong dc electric field

    International Nuclear Information System (INIS)

    Harries, James R.; Sullivan, James P.; Sternberg, James B.; Obara, Satoshi; Suzuki, Tadayuki; Azuma, Yoshiro; Hammond, Peter; Bozek, John; Berrah, Nora; Halka, Monica

    2003-01-01

    We report the first experimental measurements of the effect of an applied field on the photoexcitation and autoionization of doubly excited states of helium. Ground-state photoionization spectra have been measured in the region below the He + (N=2) threshold with static electric fields of up to 84.4 kV/cm across the interaction region. The results are compared to the theoretical calculations of Chung et al. [J. Phys. B10.1088/0953-4075/34/2/304 34, 165 (2001)], which are the only calculations available in this regime. Transitions to several states in the N=2, n=6 manifold are assigned, and a wealth of new structure is observed. Our data show that many more series are mixed in by the field than those predicted by theory

  9. Radial electric field and ion parallel flow in the quasi-symmetric and Mirror configurations of HSX

    Science.gov (United States)

    Kumar, S. T. A.; Dobbins, T. J.; Talmadge, J. N.; Wilcox, R. S.; Anderson, D. T.

    2018-05-01

    The radial electric field and the ion mean parallel flow are obtained in the helically symmetric experiment stellarator from toroidal flow measurements of C+6 ion at two locations on a flux surface, using the Pfirsch–Schlüter effect. Results from the standard quasi-helically symmetric magnetic configuration are compared with those from the Mirror configuration where the quasi-symmetry is deliberately degraded using auxiliary coils. For similar injected power, the quasi-symmetric configuration is observed to have significantly lower flows while the experimental observations from the Mirror geometry are in better agreement with neoclassical calculations. Indications are that the radial electric field near the core of the quasi-symmetric configuration may be governed by non-neoclassical processes.

  10. Redshift of A 1(longitudinal optical) mode for GaN crystals under strong electric field

    Science.gov (United States)

    Gu, Hong; Wu, Kaijie; Zheng, Shunan; Shi, Lin; Zhang, Min; Liu, Zhenghui; Liu, Xinke; Wang, Jianfeng; Zhou, Taofei; Xu, Ke

    2018-01-01

    We investigated the property of GaN crystals under a strong electric field. The Raman spectra of GaN were measured using an ultraviolet laser, and a remarkable redshift of the A 1(LO) mode was observed. The role of the surface depletion layer was discussed, and the interrelation between the electric field and phonons was revealed. First-principles calculations indicated that, in particular, the phonons that vibrate along the [0001] direction are strongly influenced by the electric field. This effect was confirmed by a surface photovoltage experiment. The results revealed the origin of the redshift and presented the phonon property of GaN under a strong electric field.

  11. Calculation of Self-consistent Radial Electric Field in Presence of Convective Electron Transport in a Stellarator

    International Nuclear Information System (INIS)

    Kernbichler, W.; Heyn, M.F.; Kasilov, S.V.

    2003-01-01

    Convective transport of supra-thermal electrons can play a significant role in the energy balance of stellarators in case of high power electron cyclotron heating. Here, together with neoclassical thermal particle fluxes also the supra-thermal electron flux should be taken into account in the flux ambipolarity condition, which defines the self-consistent radial electric field. Since neoclassical particle fluxes are non-linear functions of the radial electric field, one needs an iterative procedure to solve the ambipolarity condition, where the supra-thermal electron flux has to be calculated for each iteration. A conventional Monte-Carlo method used earlier for evaluation of supra-thermal electron fluxes is rather slow for performing the iterations in reasonable computer time. In the present report, the Stochastic Mapping Technique (SMT), which is more effective than the conventional Monte Carlo method, is used instead. Here, the problem with a local monoenergetic supra-thermal particle source is considered and the effect of supra-thermal electron fluxes on both, the self-consistent radial electric field and the formation of different roots of the ambipolarity condition are studied

  12. Green Functions for the Radial Electric Component of the Monopole Wake Field in a Round Resistive Chamber

    International Nuclear Information System (INIS)

    Zimmermann, Frank

    1998-01-01

    We compare different approximations to the point-charge Green function for the radial electric monopole field excited by an ultrarelativistic particle propagating through a resistive pipe, and study the applicability of these approximations for calculating the field of a bunch with finite length. It has been speculated that the exact form of the electric field could be important for simulations of the electron-cloud instability. In this paper, we show, however, that the usual approximation of the Green function by a delta function is adequate, except for extremely short bunch lengths

  13. Simulating radial diffusion of energetic (MeV electrons through a model of fluctuating electric and magnetic fields

    Directory of Open Access Journals (Sweden)

    T. Sarris

    2006-10-01

    Full Text Available In the present work, a test particle simulation is performed in a model of analytic Ultra Low Frequency, ULF, perturbations in the electric and magnetic fields of the Earth's magnetosphere. The goal of this work is to examine if the radial transport of energetic particles in quiet-time ULF magnetospheric perturbations of various azimuthal mode numbers can be described as a diffusive process and be approximated by theoretically derived radial diffusion coefficients. In the model realistic compressional electromagnetic field perturbations are constructed by a superposition of a large number of propagating electric and consistent magnetic pulses. The diffusion rates of the electrons under the effect of the fluctuating fields are calculated numerically through the test-particle simulation as a function of the radial coordinate L in a dipolar magnetosphere; these calculations are then compared to the symmetric, electromagnetic radial diffusion coefficients for compressional, poloidal perturbations in the Earth's magnetosphere. In the model the amplitude of the perturbation fields can be adjusted to represent realistic states of magnetospheric activity. Similarly, the azimuthal modulation of the fields can be adjusted to represent different azimuthal modes of fluctuations and the contribution to radial diffusion from each mode can be quantified. Two simulations of quiet-time magnetospheric variability are performed: in the first simulation, diffusion due to poloidal perturbations of mode number m=1 is calculated; in the second, the diffusion rates from multiple-mode (m=0 to m=8 perturbations are calculated. The numerical calculations of the diffusion coefficients derived from the particle orbits are found to agree with the corresponding theoretical estimates of the diffusion coefficient within a factor of two.

  14. Phase diagrams and radial distribution of the electric field components of coaxial discharges with outer dielectric tube at different wave modes

    International Nuclear Information System (INIS)

    Neichev, Z; Benova, E; Gamero, A; Sola, A

    2007-01-01

    The purpose of this work is to investigate phase diagrams and electric field radial distribution of coaxial discharges, sustained by a traveling electromagnetic wave, assuming finite and infinite thickness of the discharge chamber in the model. The calculations are made for azimuthally symmetric and dipolar wave modes. The phase diagrams and the radial profiles of the electric field at various thicknesses of the outer dielectric tube of the chamber and different discharge conditions are obtained. For the purpose of low pressure coaxial plasma modelling, radial profiles of the electric field at different discharge conditions have been investigated experimentally and compared with the theoretical results

  15. Poloidal rotation dynamics, radial electric field, and neoclassical theory in the jet internal-transport-barrier region.

    Science.gov (United States)

    Crombé, K; Andrew, Y; Brix, M; Giroud, C; Hacquin, S; Hawkes, N C; Murari, A; Nave, M F F; Ongena, J; Parail, V; Van Oost, G; Voitsekhovitch, I; Zastrow, K-D

    2005-10-07

    Results from the first measurements of a core plasma poloidal rotation velocity (upsilontheta) across internal transport barriers (ITB) on JET are presented. The spatial and temporal evolution of the ITB can be followed along with the upsilontheta radial profiles, providing a very clear link between the location of the steepest region of the ion temperature gradient and localized spin-up of upsilontheta. The upsilontheta measurements are an order of magnitude higher than the neoclassical predictions for thermal particles in the ITB region, contrary to the close agreement found between the determined and predicted particle and heat transport coefficients [K.-D. Zastrow, Plasma Phys. Controlled Fusion 46, B255 (2004)]. These results have significant implications for the understanding of transport barrier dynamics due to their large impact on the measured radial electric field profile.

  16. Kinetic theory of wave spectra in semiconductors at the strong constant electric field

    International Nuclear Information System (INIS)

    Grinev, B.V.; Seminozhenko, V.P.; Yatsenko, A.A.

    1984-01-01

    With allowanse made for the effect of strong static electric field on the electronic interaction with collective oscillations in plasms, the Languemure oscillations, ion acoustic instability of plasma with current are considered in the collisionless limit. The electric field dependence of the collisionless damping of transversal wayes is determined borh in the degenerate and the nondegenerate cases. The influence of the constant electric field on the anomalous skineffect isstudied

  17. Radial electric field at the plasma edge on the FT-2 Tokamak in regimes with large gradients

    International Nuclear Information System (INIS)

    Lashkul, S.; Popov, A.

    2001-01-01

    The transport barrier formation is widely believed to be the fundamental element of transition into improved confinement regimes (H-mode). Experiments on many tokamaks demonstrate that transport barrier formation is connected with the suppression of turbulent transport by shear of E x B drift. Therefore, the calculation of radial electric field is of great importance. Our work is devoted to progress the neoclassical theory by taking into account electron viscosity and non-linear effects (ion inertia), presented results being valuable for interpretation transition into H-mode at the plasma edge in small tokamaks. Calculations of the electric field profile for FT-2 tokamak (a=8cm, R 0 =55cm, Ioffe Institute, Russia) according found expressions are in the good agreement with experimental results obtained. (orig.)

  18. Influence of the radial spacing between cathodes on the surface composition of iron samples sintered by hollow cathode electric discharge

    Directory of Open Access Journals (Sweden)

    Brunatto S.F.

    2001-01-01

    Full Text Available The present work reports an investigation of the influence of the radial spacing between cathodes on the iron sintering process by hollow cathode electrical discharge, with surface enrichment of the alloying elements Cr and Ni. Pressed cylindrical samples of 9.5 mm diameter and density of 7.0 ± 0.1 g/cm³ were prepared by compaction of Ancorsteel 1000C iron powder. These samples, constituting the central cathode, were positioned concentrically in the interior of an external cathode machined from a tube of stainless steel AISI 310 (containing: 25% Cr, 16% Ni, 1.5% Mn, 1.5% Si, 0.03% C and the remainder Fe. Sintering was done at 1150 °C, for 120 min, utilizing radial spacings between the central and hollow cathodes of 3, 6 and 9 mm and a gas mixture of 80% Ar and 20% H2, with a flow rate of 5 cm³/s at a pressure of 3 Torr. The electric discharge was generated using a pulsed voltage power source, with a period of 200 mus. The radial spacing had only a slight influence on the quantity of atoms of alloying elements deposited and diffused on the surface of the sample. Analysis with a microprobe showed the presence of chrome (up to 4.0% and nickel (up to 3.0%, in at. % at the surface of the samples. This surface enrichment can be attributed to the mechanism of sputtering of the metallic atoms present in the external cathode, with the deposition of these elements on the sample surface and consequent diffusion within the sample.

  19. Radial density distribution of a warm dense plasma formed by underwater electrical explosion of a copper wire

    Science.gov (United States)

    Nitishinskiy, M.; Yanuka, D.; Virozub, A.; Krasik, Ya. E.

    2017-12-01

    Time- and space-resolved evolution of the density (down to 0.07 of solid state density) of a copper wire during its microsecond timescale electrical explosion in water was obtained by X-ray backlighting. In the present research, a flash X-ray source of 20 ns pulse-width and >60 keV photon energy was used. The conductivity of copper was evaluated for a temperature of 10 kK and found to be in good agreement with the data obtained in earlier experiments [DeSilva and Katsouros, Phys. Rev. E 57, 5945 (1998) and Sheftman and Krasik, Phys. Plasmas 18, 092704 (2011)] where only electrical and optical diagnostics were applied. Magneto-hydrodynamic simulation shows a good agreement between the simulated and experimental waveforms of the current and voltage and measured the radial expansion of the exploding wire. Also, the radial density distribution obtained by an inverse Abel transform analysis agrees with the results of these simulations. Thus, the validity of the equations of state for copper and the conductivity model used in the simulations was confirmed for the parameters of the exploding wire realized in the present research.

  20. On the applicability of the standard approaches for evaluating a neoclassical radial electric field in a tokamak edge region

    Energy Technology Data Exchange (ETDEWEB)

    Dorf, M. A.; Cohen, R. H.; Joseph, I. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Simakov, A. N. [Los Alamos National Laboratory, Los Alamos, New Mexico 87544 (United States)

    2013-08-15

    The use of the standard approaches for evaluating a neoclassical radial electric field E{sub r}, i.e., the Ampere (or gyro-Poisson) equation, requires accurate calculation of the difference between the gyroaveraged electron and ion particle fluxes (or densities). In the core of a tokamak, the nontrivial difference appears only in high-order corrections to a local Maxwellian distribution due to the intrinsic ambipolarity of particle transport. The evaluation of such high-order corrections may be inconsistent with the accuracy of the standard long wavelength gyrokinetic equation (GKE), thus imposing limitations on the applicability of the standard approaches. However, in the edge of a tokamak, charge-exchange collisions with neutrals and prompt ion orbit losses can drive non-intrinsically ambipolar particle fluxes for which a nontrivial (E{sub r}-dependent) difference between the electron and ion fluxes appears already in a low order and can be accurately predicted by the long wavelength GKE. The parameter regimes, where the radial electric field dynamics in the tokamak edge region is dominated by the non-intrinsically ambipolar processes, thus allowing for the use of the standard approaches, are discussed.

  1. Corrections for a constant radial magnetic field in the muon g - 2 and electric-dipole-moment experiments in storage rings

    Energy Technology Data Exchange (ETDEWEB)

    Silenko, Alexander J. [Belarusian State University, Research Institute for Nuclear Problems, Minsk (Belarus); Joint Institute for Nuclear Research, Bogoliubov Laboratory of Theoretical Physics, Dubna (Russian Federation)

    2017-10-15

    We calculate the corrections for constant radial magnetic field in muon g - 2 and electric-dipole-moment experiments in storage rings. While the correction is negligible for the current generation of g - 2 experiments, it affects the upcoming muon electric-dipole-moment experiment at Fermilab. (orig.)

  2. Corrections for a constant radial magnetic field in the muon \\varvec{g}-2 and electric-dipole-moment experiments in storage rings

    Science.gov (United States)

    Silenko, Alexander J.

    2017-10-01

    We calculate the corrections for constant radial magnetic field in muon {g}-2 and electric-dipole-moment experiments in storage rings. While the correction is negligible for the current generation of {g}-2 experiments, it affects the upcoming muon electric-dipole-moment experiment at Fermilab.

  3. Advances in potential formation and findings in sheared radial electric-field effects on turbulence and loss suppression in GAMMA 10

    International Nuclear Information System (INIS)

    Cho, T.; Higaki, H.; Hirata, M.; Hojo, H.; Ichimura, M.; Ishii, K.; Islam, M.K.; Itakura, A.; Katanuma, I.; Kohagura, J.; Nakashima, Y.; Numakura, T.; Saito, T.; Tatematsu, Y.; Yoshikawa, M.; Yoshida, M.; Imai, T.; Pastukhov, V.P.; Miyoshi, S.

    2005-01-01

    Following the Lyon IAEA Conference, (1) a factor of three progress up to 2.1 kV in the formation of ion-confining potential heights in comparison to those attained 1992-2002 is achieved for tandem-mirror plasmas in the hot-ion mode with ion temperatures of several keV. (2) The advance in the potential formation gives bases for a finding of the remarkable effects of radially produced shear of electric fields E r , or non-uniform sheared plasma rotation Ω r =E r /(r c B) on the suppression of turbulent fluctuations for the first time in GAMMA 10. (Here, r c denotes a radius mapped to the central-cell.) (2-i) Such a shear effect on the central-cell plasmas is highlighted visually by x-ray tomography diagnostics; that is, spatially and temporally fluctuated vortex-like structures are clearly observed in plasmas produced by ICH alone [having a quite weak shear]. (2-ii) However, during the application of plug ECH into the ICH plasmas, an associated potential rise produces a stronger shear [E r =several 10 kV/m 2 ]. In this case, the disappearance of the turbulent vortices on the basis of such a high-potential formation due to ECH is found in association with plasma confinement improvement. In fact, the associated temperature rise and transverse loss suppression are observed. (3) From the viewpoints of both (i) a conventional idea of higher and better potential confinement in the axial direction [i.e., E z effects] and (ii) the present new finding of a turbulent vortex disappearance due to a strong radial electric shear [i.e., E r effects] in the transverse direction, simultaneously, such a high potential formation is found to play an essential role in providing stably improved plasma confinement both radially and axially. (4) For the physics interpretations and control of such potential [or the associated E r or Ψ r shear] formation, the validity of our proposed theory of the potential formation is extendedly tested under the conditions with auxiliary heatings. The

  4. Heuristic for solving capacitor allocation problems in electric energy radial distribution networks

    Directory of Open Access Journals (Sweden)

    Maria A. Biagio

    2012-04-01

    Full Text Available The goal of the capacitor allocation problem in radial distribution networks is to minimize technical losses with consequential positive impacts on economic and environmental areas. The main objective is to define the size and location of the capacitors while considering load variations in a given horizon. The mathematical formulation for this planning problem is given by an integer nonlinear mathematical programming model that demands great computational effort to be solved. With the goal of solving this problem, this paper proposes a methodology that is composed of heuristics and Tabu Search procedures. The methodology presented explores network system characteristics of the network system reactive loads for identifying regions where procedures of local and intensive searches should be performed. A description of the proposed methodology and an analysis of computational results obtained which are based on several test systems including actual systems are presented. The solutions reached are as good as or better than those indicated by well referenced methodologies. The technique proposed is simple in its use and does not require calibrating an excessive amount of parameters, making it an attractive alternative for companies involved in the planning of radial distribution networks.

  5. Absolute and convective instabilities of a film flow down a vertical fiber subjected to a radial electric field

    Science.gov (United States)

    Liu, Rong; Chen, Xue; Ding, Zijing

    2018-01-01

    We consider the motion of a gravity-driven flow down a vertical fiber subjected to a radial electric field. This flow exhibits rich dynamics including the formation of droplets, or beads, driven by a Rayleigh-Plateau mechanism modified by the presence of gravity as well as the Maxwell stress at the interface. A spatiotemporal stability analysis is performed to investigate the effect of electric field on the absolute-convective instability (AI-CI) characteristics. We performed a numerical simulation on the nonlinear evolution of the film to examine the transition from CI to AI regime. The numerical results are in excellent agreement with the spatiotemporal stability analysis. The blowup behavior of nonlinear simulation predicts the formation of touchdown singularity of the interface due to the effect of electric field. We try to connect the blowup behavior with the AI-CI characteristics. It is found that the singularities mainly occur in the AI regime. The results indicate that the film may have a tendency to form very sharp tips due to the enhancement of the absolute instability induced by the electric field. We perform a theoretical analysis to study the behaviors of the singularities. The results show that there exists a self-similarity between the temporal and spatial distances from the singularities.

  6. MgB2 superconducting particles in a strong electric field

    International Nuclear Information System (INIS)

    Tao, R.; Xu, X.; Amr, E.

    2003-01-01

    The electric-field induced ball formation has been observed with MgB 2 powder in a strong static or quasi-static electric field. The effect of temperature and magnetic field on the ball formation shows surprising features. For quite a wide range of temperature from T c =39 K and below, the ball size is proportional to (1-T/T c ). As the temperature further goes below 20 K, the ball size becomes almost a constant. If MgB 2 particles are in a strong electric field and a moderate magnetic field, the electric-field induced balls align in the magnetic-field direction to form ball chains

  7. Electrically tunable single-dot nanocavities in the weak and strong coupling regimes

    DEFF Research Database (Denmark)

    Laucht, Arne; Hofbauer, Felix; Angele, Jacob

    2008-01-01

    We report the design, fabrication and optical investigation of electrically tunable single quantum dot - photonic crystal defect nanocavities [1] operating in both the weak and strong coupling regimes of the light matter interaction. Unlike previous studies, where the dot-cavity spectral detuning...... of the emitted photons from a single-dot nanocavity in the weak and strong coupling regimes. New information is obtained on the nature of the dot-cavity coupling in the weak coupling regime and electrical control of zero dimensional polaritons is demonstrated for the first time. Vacuum Rabi splittings up to 2g...... electrical readout of the strongly coupled dot-cavity system using photocurrent methods will be discussed. This work is financially supported by the DFG via SFB 631 and by the German Excellence Initiative via the “Nanosystems Initiative Munich (NIM)”....

  8. Multi nodal load forecasting in electric power systems using a radial basis neural network; Previsao de carga multinodal em sistemas eletricos de potencia usando uma rede neural de base radial

    Energy Technology Data Exchange (ETDEWEB)

    Altran, A.B.; Lotufo, A.D.P.; Minussi, C.R. [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Ilha Solteira, SP (Brazil). Dept. de Engenharia Eletrica], Emails: lealtran@yahoo.com.br, annadiva@dee.feis.unesp.br, minussi@dee.feis.unesp.br; Lopes, M.L.M. [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Ilha Solteira, SP (Brazil). Dept. de Matematica], E-mail: mara@mat.feis.unesp.br

    2009-07-01

    This paper presents a methodology for electrical load forecasting, using radial base functions as activation function in artificial neural networks with the training by backpropagation algorithm. This methodology is applied to short term electrical load forecasting (24 h ahead). Therefore, results are presented analyzing the use of radial base functions substituting the sigmoid function as activation function in multilayer perceptron neural networks. However, the main contribution of this paper is the proposal of a new formulation of load forecasting dedicated to the forecasting in several points of the electrical network, as well as considering several types of users (residential, commercial, industrial). It deals with the MLF (Multimodal Load Forecasting), with the same processing time as the GLF (Global Load Forecasting). (author)

  9. Ethylene Removal in Strong Electric Field Formed by Floating Multi-Electrode

    Science.gov (United States)

    Nagasawa, Takeshi

    Ethylene gas that contains the acetic acid ester element can be removed by applying the pulse voltage to the floating multi-electrode device. This phenomenon is caused in the weak discharge by the strong electric field between the narrow electrodes. This device is possible in very small electric power (apples, and 3.5ppm/30min for 2 melons. However, ethylene gas that doesn't contain the acetic acid ester cannot be removed (ex. ethylene pure gas and Japanese apricot).

  10. Cavity opto-electromechanical system combining strong electrical actuation with ultrasensitive transduction

    OpenAIRE

    McRae, Terry G.; Lee, Kwan H.; Harris, Glen I.; Knittel, Joachim; Bowen, Warwick P.

    2010-01-01

    A cavity opto-electromechanical system is reported which combines the ultrasensitive transduction of cavity optomechanical systems with the electrical actuation of nanoelectromechanical systems. Ultrasensitive mechanical transduction is achieved via opto-mechanical coupling. Electrical gradient forces as large as 0.40 $\\mu$N are realized, facilitating strong actuation with ultralow dissipation. A scanning probe microscope is implemented, capable of characterizing the mechanical modes. The int...

  11. Competition Between Radial Loss and EMIC Wave Scattering of MeV Electrons During Strong CME-shock Driven Storms

    Science.gov (United States)

    Hudson, M. K.; Jaynes, A. N.; Li, Z.; Malaspina, D.; Millan, R. M.; Patel, M.; Qin, M.; Shen, X.; Wiltberger, M. J.

    2017-12-01

    The two strongest storms of Solar Cycle 24, 17 March and 22 June 2015, provide a contrast between magnetospheric response to CME-shocks at equinox and solstice. The 17 March CME-shock initiated storm produced a stronger ring current response with Dst = - 223 nT, while the 22 June CME-shock initiated storm reached a minimum Dst = - 204 nT. The Van Allen Probes ECT instrument measured a dropout in flux for both events which can be characterized by magnetopause loss at higher L values prior to strong recovery1. However, rapid loss is seen at L 3 for the June storm at high energies with maximum drop in the 5.2 MeV channel of the REPT instrument coincident with the observation of EMIC waves in the H+ band by the EMFISIS wave instrument. The rapid time scale of loss can be determined from the 65 minute delay in passage of the Probe A relative to the Probe B spacecraft. The distinct behavior of lower energy electrons at higher L values has been modeled with MHD-test particle simulations, while the rapid loss of higher energy electrons is examined in terms of the minimum resonant energy criterion for EMIC wave scattering, and compared with the timescale for loss due to EMIC wave scattering which has been modeled for other storm events.2 1Baker, D. N., et al. (2016), Highly relativistic radiation belt electron acceleration, transport, and loss: Large solar storm events of March and June 2015, J. Geophys. Res. Space Physics, 121, 6647-6660, doi:10.1002/2016JA022502. 2Li, Z., et al. (2014), Investigation of EMIC wave scattering as the cause for the BARREL 17 January 2013 relativistic electron precipitation event: A quantitative comparison of simulation with observations, Geophys. Res. Lett., 41, 8722-8729, doi:10.1002/2014GL062273.

  12. Radial electric field and rotation of the ensemble of plasma particles in tokamak

    International Nuclear Information System (INIS)

    Sorokina, E. A.; Ilgisonis, V. I.

    2012-01-01

    The velocity of macroscopic rotation of an ensemble of charged particles in a tokamak in the presence of an electric field has been calculated in a collisionless approximation. It is shown that the velocity of toroidal rotation does not reduce to a local velocity of electric drift and has opposite directions on the inner and outer sides of the torus. This result is supplemented by an analysis of the trajectories of motion of individual particles in the ensemble, which shows that the passing and trapped particles of the ensemble acquire in the electric field, on the average, different toroidal velocities. For the trapped particles, this velocity is equal to that of electric drift in the poloidal magnetic field, while the velocity of passing particles is significantly different. It is shown that, although the electric-field-induced shift of the boundaries between trapped and passing particles in the phase space depends on the particle mass and charge and is, in the general case, asymmetric, this does not lead to current generation.

  13. Imaging axial and radial electric field components in dielectric targets under plasma exposure

    NARCIS (Netherlands)

    Slikboer, E.T.; Sobota, A.; Guaitella, O.; Garcia-Caurel, E.

    2018-01-01

    This work presents new ways to investigate the individual electric field components in a dielectric target induced by a non thermal atmospheric pressure plasma jet. Mueller polarimetry is applied to investigate electro-optic crystals under exposure of guided ionization waves produced by a plasma

  14. Radially and temporally resolved electric field of positive streamers in air and modelling of the induced plasma chemistry

    Science.gov (United States)

    Hoder, T.; Šimek, M.; Bonaventura, Z.; Prukner, V.; Gordillo-Vázquez, F. J.

    2016-08-01

    The initial stages of transient luminous events (TLEs) occurring in the upper atmosphere of the Earth are, in a certain pressure range, controlled by the streamer mechanism. This paper presents the results of the first laboratory experiments to study the TLE streamer phenomena under conditions close to those of the upper atmosphere. Spectrally and highly spatiotemporally resolved emissions originating from radiative states {{\\text{N}}2}≤ft({{\\text{C}}3}{{\\Pi}u}\\right) (second positive system) and \\text{N}2+≤ft({{\\text{B}}2}Σu+\\right) (first negative system) have been recorded from the positive streamer discharge. Periodic ionizing events were generated in a barrier discharge arrangement at a pressure of 4 torr of synthetic air, i.e. simulating the pressure conditions at altitudes of ≃37 km. Employing Abel inversion on the radially scanned streamer emission and a 2D fitting procedure, access was obtained to the local spectral signatures within the over 106  m s-1 fast propagating streamers. The reduced electric field strength distribution within the streamer head was determined from the ratio of the \\text{N}2+/{{\\text{N}}2} band intensities with peak values up to 500 Td and overall duration of about 10 ns. The 2D profiles of the streamer head electric fields were used as an experimentally obtained input for kinetic simulations of the streamer-induced air plasma chemistry. The radial and temporal computed distribution of the ground vibrational levels of the radiative states involved in the radiative transitions analyzed (337.1 nm and 391.5 nm), atomic oxygen, nitrogen, nitric oxide and ozone concentrations are vizualized and discussed in comparison with available models of the streamer phase of Blue Jet discharges in the stratosphere.

  15. Dirac particles in the field of magnetic monopoles and of strong electric charges

    International Nuclear Information System (INIS)

    Schafer, A.; Muller, B.; Greiner, W.

    1985-01-01

    The field of a magnetic pointlike monopole acts in a similar way on a charged Dirac particle as the field of a very strong electric point charge. To explore this parallel it is constructed a field solution for an extended magnetic-charge distribution. In contrast to what is found for extended electric charges, the Hamiltonian remains nonself-adjoint for an extended magnetic monopole. This suggests that there exist a fundamental difference between the two cases. In particular, the appearance of undefined states for point monopoles is not a consequence of the mere strength of the magnetic-monopole charge, which has a minimum value fixed by Dirac's quantization condition

  16. First in situ measurement of electric field fluctuations during strong spread F in the Indian zone

    Directory of Open Access Journals (Sweden)

    H. S. S. Sinha

    2000-05-01

    Full Text Available An RH-560 rocket flight was conducted from Sriharikota rocket range (SHAR (14°N, 80°E, dip 14°N along with other experiments, as a part of equatorial spread F (ESF campaign, to study the nature of irregularities in electric field and electron density. The rocket was launched at 2130 local time (LT and it attained an apogee of 348 km. Results of vertical and horizontal electric field fluctuations are presented here. Scale sizes of electric field fluctuations were measured in the vertical direction only. Strong ESF irregularities were observed in three regions, viz., 160-190 km, 210-257 km and 290-330 km. Some of the valley region vertical electric field irregularities (at 165 km and 168 km, in the intermediate-scale size range, observed during this flight, show spectral peak at kilometer scales and can be interpreted in terms of the image striation theory suggested by Vickrey et al. The irregularities at 176 km do not exhibit any peak at kilometer scales and appear to be of a new type. Scale sizes of vertical electric field fluctuations showed a decrease with increasing altitude. The most prominent scales were of the order of a few kilometers around 170 km and a few hundred meters around 310 km. Spectra of intermediate-scale vertical electric field fluctuations below the base of the F region (210-257 km showed a tendency to become slightly flatter (spectral index n = -2.1 ± 0.7 as compared to the valley region (n = -3.6 ± 0.8 and the region below the F peak (n = -2.8 ± 0.5. Correlation analysis of the electron density and vertical electric field fluctuations suggests the presence of a sheared flow of current in 160-330 km region.Keywords: Ionosphere (Electric fields and currents; ionospheric irregularities; Radio science (ionospheric physics

  17. Hydrodynamical flows in dielectric liquid in strong inhomogeneous pulsed electric field

    International Nuclear Information System (INIS)

    Tereshonok, Dmitry V; Babaeva, Natalia Yu; Naidis, George V; Smirnov, Boris M

    2016-01-01

    We consider a hydrodynamical flow of dielectric liquid near a high voltage needle-shaped electrode in a strong inhomogeneous pulsed electric field. It was shown that under a small rise time, a negative pressure area (pressure is less than critical pressure) appears near the electrode leading to the formation of a cavity in which electric breakdown can develop. A comparison of the dependence of the velocity of fluid near an electrode for two cases (taking into account the dependence of dielectric permeability of the liquid on the electric field and without taking it into account) was made. A field-dependent dielectric coefficient leads to the appearance of two local maximums of the velocities and increases the minimum pressure, thus lowering the possibility of cavitation. While under the constant value of dielectric permeability only one local maximum appears. (paper)

  18. Controlled self-assembly of multiferroic core-shell nanoparticles exhibiting strong magneto-electric effects

    Energy Technology Data Exchange (ETDEWEB)

    Sreenivasulu, Gollapudi; Hamilton, Sean L.; Lehto, Piper R.; Srinivasan, Gopalan, E-mail: srinivas@oakland.edu [Physics Department, Oakland University, Rochester, Michigan 48309-4401 (United States); Popov, Maksym [Physics Department, Oakland University, Rochester, Michigan 48309-4401 (United States); Radiophysics Department, Taras Shevchenko National University of Kyiv, Kyiv 01601 (Ukraine); Chavez, Ferman A. [Chemistry Department, Oakland University, Rochester, Michigan 48309-4401 (United States)

    2014-02-03

    Ferromagnetic-ferroelectric composites show strain mediated coupling between the magnetic and electric sub-systems due to magnetostriction and piezoelectric effects associated with the ferroic phases. We have synthesized core-shell multiferroic nano-composites by functionalizing 10–100 nm barium titanate and nickel ferrite nanoparticles with complementary coupling groups and allowing them to self-assemble in the presence of a catalyst. The core-shell structure was confirmed by electron microscopy and magnetic force microscopy. Evidence for strong strain mediated magneto-electric coupling was obtained by static magnetic field induced variations in the permittivity over 16–18 GHz and polarization and by electric field induced by low-frequency ac magnetic fields.

  19. Dynamics of particle production by strong electric fields in non-Abelian plasmas

    International Nuclear Information System (INIS)

    Dawson, John F.; Mihaila, Bogdan; Cooper, Fred

    2010-01-01

    We develop methods for computing the dynamics of fermion pair production by strong color electric fields including backreaction using the semiclassical Boltzmann-Vlasov (B-V) equation. We implement the Schwinger pair production by inserting a source term in the B-V equation which includes Pauli-Blocking effects. We present numerical results for a model with SU(2) symmetries in (1+1) Cartesian dimensions.

  20. Electrical control of spontaneous emission and strong coupling for a single quantum dot

    DEFF Research Database (Denmark)

    Laucht, A.; Hofbauer, F.; Hauke, N.

    2009-01-01

    We report the design, fabrication and optical investigation of electrically tunable single quantum dots—photonic crystal defect nanocavities operating in both the weak and strong coupling regimes of the light–matter interaction. Unlike previous studies where the dot–cavity spectral detuning...... switchable optical nonlinearity at the single photon level, paving the way towards on-chip dot-based nano-photonic devices that can be integrated with passive optical components....

  1. The electrical characteristic and gain behavior as a function of the radial distance from the laser axis in a copper vapor laser

    International Nuclear Information System (INIS)

    Gal, G.

    1989-06-01

    The dependence of few parameters (related to the laser gain) on the radial distance from the laser axis, is observed very easily in a large-bore Copper Vapor Laser (CVL). An 80-mm-bore CVL which has reproducible parameters for research purposes has been constructed. The temporal development of the gain at different radial distances in this laser has been measured. A narrow probing beam from a small CVL operating as a oscillator has been used for the measurements, while the large-bore CVL has been operated as an amplifier and probed by this beam at different radial points. The electric response of the laser has also been checked and lead to the conclusion that raising the electrons energy in the laser plasma entails higher gain. As the laser tube wall was moved towards the laser axis, a temporal lag in the gain development and a reduction in its size has been found. The temporal lag is related to skin effect which delays the penetration of the electric field in the plasma towards the laser axis. The reduction in gain is related to the radial dependence of the population of the laser lower levels. It has also been found that under saturation the average power per unit area extracted from the laser is weakly dependent on the radial distance. (author)

  2. Operating an EPR: A strong asset in the future European electricity market

    International Nuclear Information System (INIS)

    Esteve, Bernard; Beutier, Didier

    2006-01-01

    Recently, two nuclear units have been decided in Europe, both EPR 1,600 MWe. In Finland, TVO Company decided to commission a reactor in 2009 on Olkiluoto site. The license was granted in February 2005 and the construction started in summer. In 2004 in France, EDF Company decided an EPR to be commissioned in 2012 at Flamanville. In both cases, national Parliament vote has given the green light. It is interesting to understand why each company has made such decision. In TVO case, the main driving factor seems to be the need of industrial consumers for low and stable electricity price in a context of growing excess demand. In EDF case, no short term demand, but rather long term electricity company strategy seems to be the main reason. The relation to national energy policy is very clear in both cases. In Finland, the 5. Nuclear Power Plant was decided: - as a key element of the energy mix to meet growing electricity needs while replacing older plants, - to ensure, together with renewables, the fulfillment of the Kyoto commitments, - to secure stable and predictable electricity price for intensive industrial consumers (for instance, paper mills), - to reduce the dependence on electricity import. Here, it is argued more broadly that EPR will be a strong asset in the future European electricity market. To support this argument, we shall describe: 1) to what extent the evolving European electricity market may call for new nuclear units, 2) specific design features explaining why EPR especially fits with expectations, 3) cost assessments giving the conditions of EPR competitiveness, 4) main elements of risk assessment and how they are dealt with. (authors)

  3. On the influence of the magnetic topology on transport and radial electric fields in the TJ-II stellarator

    International Nuclear Information System (INIS)

    Castejon, F.; Ochando, M.; Estrada, T.; Pedrosa, M.A.; Lopez-Bruna, D.; Ascasibar, E.; Cappa, A.; Eguilior, S.; Fernandez-Curto, A.; Herranz, J.; Hidalgo, C.; Lopez-Fraguas, A.; Melnikov, A.V.; McCarthy, K.J.; Medina, F.; Pastor, I.; Chmyga, A.A.; Dreval, N.B.; Khrebtov, S.M.; Komarov, A.D.; Kozachok, A.S.; Krupnik, L.; Eliseev, L.

    2005-01-01

    The influence of the magnetic topology on plasma profiles and turbulence has been investigated in ECH plasmas in the stellarator TJ-II, taking advantage of the flexibility of this almost shearless device. A wide range of edge rotational transform values can be attained, but the rotational transform profile can also be tailored by inducing currents using both ECCD and two sets of OH coils. In this way it is possible to introduce rational surfaces inside the plasma and to modify the magnetic shear to examine their effect on confinement. Kinetic effects and flux changes due to the presence of resonances and ECRH are responsible of the formation of barriers in the plasma core, while the shear flow is a key ingredient in the plasma edge. The results here shown offer wide and valuable information to assess multiple mechanisms based on neoclassical/turbulent bifurcations and kinetic effects as candidates to explain the impact of magnetic topology on radial electric fields and confinement. (author)

  4. Trapped particle confinement studies in L = 2 torsatrons for additional helical coils, radial electric field and finite beta effect

    International Nuclear Information System (INIS)

    Kato, A.; Nakamura, Y.; Wakatani, M.

    1990-07-01

    L = 2 torsatrons are studied to improve the high energy trapped particle confinement with additional l = 1 and/or l = 3 helical coils. The winding laws are selected in two ways. One is to realize 'σ - optimization' by the additional helical coils, but this approach loses magnetic well region. The other selection is to produce or deepen the magnetic well by the additional helical coils. L=3 helical coils are usable to this end. In this case the improvement of the trapped particle confinement depends on magnetic axis position. Radial electric field producing sheared rotational motion is also considered to improve the trapped particle confinement in a standard l = 2 torsatron. By excluding cancellation between E x B and ΔB drift motion occurred for the parabolic potential profiles, all deeply trapped particles can be confined in the central region. Degradation of the trapped particle confinement by the Shafranov shift is mitigated by shifting the magnetic axis inside in the vacuum configuration. (author)

  5. A nonlinear efficient layerwise finite element model for smart piezolaminated composites under strong applied electric field

    International Nuclear Information System (INIS)

    Kapuria, S; Yaqoob Yasin, M

    2013-01-01

    In this work, we present an electromechanically coupled efficient layerwise finite element model for the static response of piezoelectric laminated composite and sandwich plates, considering the nonlinear behavior of piezoelectric materials under strong electric field. The nonlinear model is developed consistently using a variational principle, considering a rotationally invariant second order nonlinear constitutive relationship, and full electromechanical coupling. In the piezoelectric layer, the electric potential is approximated to have a quadratic variation across the thickness, as observed from exact three dimensional solutions, and the equipotential condition of electroded piezoelectric surfaces is modeled using the novel concept of an electric node. The results predicted by the nonlinear model compare very well with the experimental data available in the literature. The effect of the piezoelectric nonlinearity on the static response and deflection/stress control is studied for piezoelectric bimorph as well as hybrid laminated plates with isotropic, angle-ply composite and sandwich substrates. For high electric fields, the difference between the nonlinear and linear predictions is large, and cannot be neglected. The error in the prediction of the smeared counterpart of the present theory with the same number of primary displacement unknowns is also examined. (paper)

  6. Electrical transverse transport in Lorentz plasma with strong magnetic field and collision effect

    International Nuclear Information System (INIS)

    Xie, Baisong; Chong, L.V.; Li, Ziliang

    2015-01-01

    In inertial confinement fusion (ICF), the spontaneous magnetic field formed from laser interacting with the pellet may reach few hundreds of Megagauss (MG) which results in the cyclotron frequency ω at the same order of the collision frequency υ. Electrical transverse transport in this case would become very important so that we study it by the Boltzmann equation for different electron density distribution. For the Maxwell distribution, it is shown that transport coefficients decrease with the increase of Ω (the ratio of ω to υ), which means the electrons would be highly collimated by strong magnetic field. This is attributed to that the electron's gyroradius is smaller than the collisional mean free paths. Moreover, the electrical transverse transport is also studied for quasi-monoenergy distribution with different width ε, which is different from the Maxwell one. It is found that the transport coefficients decrease greatly as quasi-monoenergy degree increases. In particular when ε approaches to zero, i.e. the Delta distribution with almost perfect monoenergy electron density, the electric conductivity doesn't change while the thermal conductivity decreases with Ω. On the other hand the smaller the ε is the less amount the transverse transport exhibits. Our study indicates that they are beneficial to limit the electric transverse transport. (author)

  7. Effect of ion orbit loss on the structure in the H-mode tokamak edge pedestal profiles of rotation velocity, radial electric field, density, and temperature

    International Nuclear Information System (INIS)

    Stacey, Weston M.

    2013-01-01

    An investigation of the effect of ion orbit loss of thermal ions and the compensating return ion current directly on the radial ion flux flowing in the plasma, and thereby indirectly on the toroidal and poloidal rotation velocity profiles, the radial electric field, density, and temperature profiles, and the interpretation of diffusive and non-diffusive transport coefficients in the plasma edge, is described. Illustrative calculations for a high-confinement H-mode DIII-D [J. Luxon, Nucl. Fusion 42, 614 (2002)] plasma are presented and compared with experimental results. Taking into account, ion orbit loss of thermal ions and the compensating return ion current is found to have a significant effect on the structure of the radial profiles of these quantities in the edge plasma, indicating the necessity of taking ion orbit loss effects into account in interpreting or predicting these quantities

  8. Nonequilibrium Thermodynamic Treatment of a Warm Plasma in Strong Magnetic and Electric Fields

    International Nuclear Information System (INIS)

    Abourabia, A.M.; Shahein, R.A.

    2008-01-01

    In the framework of the irreversible thermodynamics we study a rarefied and collisional warm electron plasma under the effects of external strong magnetic and electric fields which generate small wave amplitudes. We adopt the linear theory and normal mode solution in the MHD model to calculate the perturbations in pressure, mass density, components of velocity, electric and magnetic fields. By applying the second law of thermodynamics it is concluded that the change in the internal energy of the plasma particles predicts whether they gain from or lose energy to the generated waves .The obtained results agree with the physical ground bounded by the positive nature of the entropy production. The predictions have been carried out within the range of the frequency of the generated waves and the distance from the Debye sphere

  9. The mechanism of strong electric field effect on the dispersed media in the rarefied gas

    International Nuclear Information System (INIS)

    Gagarin, A.G.; Savchenko, Y.N.; Vigdonchik, V.H.

    1985-01-01

    This paper discusses two approaches to the description of the flow of fluids and gases, that is, a phenomenological method and a molecular-kinetic method. Four dispersed admixtures are described using the model of solid spheres as for molecules and a system of aerodynamic equations is obtained. In this system interactions between gas molecules and admixtures are taken into consideration already in the zero approximation. The paper is also concerned with the experimental study of the motion of dispersed particles in corona discharge which is a typical example of a strong nonuniform electric field with a volume discharge. From the comparison of experimental and calculated paths it was found that the particles move five to seven times faster than they would have done under the action of the Coulomb force alone at a real amount of charge of the particle. The result of comparison also shows that their motion primarily depends on the jet flow of electric wind

  10. Main tasks of studying strong regulation of excitation of complex electrical system generators

    Energy Technology Data Exchange (ETDEWEB)

    Gruzdev, I.A.; Yekimova, M.M.

    1982-01-01

    A survey is made of the current state of studies of the damping properties of complex electricity systems. The calculation programs of stability are based on frequency methods using the method of D-division. Now, when ARV of strong effect dominates at the SG, the task of coordinating their adjustments develops. Consequently, the following questions are discussed: study of the properties of quality functional with several points of regulation in the circuits of different structure; development of the efficient procedures for coordinating the ARV adjustment of the related energy systems; and creation of resources for solving these tasks. Results are presented of coordinating the ARV adjustments of the generators of the 3-machine electricity system. As an example, nonlinear relationships are shown between the obtained degree of stability and the coefficient of stabilization.

  11. First in situ measurement of electric field fluctuations during strong spread F in the Indian zone

    Directory of Open Access Journals (Sweden)

    H. S. S. Sinha

    Full Text Available An RH-560 rocket flight was conducted from Sriharikota rocket range (SHAR (14°N, 80°E, dip 14°N along with other experiments, as a part of equatorial spread F (ESF campaign, to study the nature of irregularities in electric field and electron density. The rocket was launched at 2130 local time (LT and it attained an apogee of 348 km. Results of vertical and horizontal electric field fluctuations are presented here. Scale sizes of electric field fluctuations were measured in the vertical direction only. Strong ESF irregularities were observed in three regions, viz., 160-190 km, 210-257 km and 290-330 km. Some of the valley region vertical electric field irregularities (at 165 km and 168 km, in the intermediate-scale size range, observed during this flight, show spectral peak at kilometer scales and can be interpreted in terms of the image striation theory suggested by Vickrey et al. The irregularities at 176 km do not exhibit any peak at kilometer scales and appear to be of a new type. Scale sizes of vertical electric field fluctuations showed a decrease with increasing altitude. The most prominent scales were of the order of a few kilometers around 170 km and a few hundred meters around 310 km. Spectra of intermediate-scale vertical electric field fluctuations below the base of the F region (210-257 km showed a tendency to become slightly flatter (spectral index n = -2.1 ± 0.7 as compared to the valley region (n = -3.6 ± 0.8 and the region below the F peak (n = -2.8 ± 0.5. Correlation analysis of the electron density and vertical electric field fluctuations suggests the presence of a sheared flow of current in 160-330 km region.

    Keywords: Ionosphere (Electric fields and currents; ionospheric irregularities; Radio science (ionospheric physics

  12. Study on the plasma reaction process of hydroxyl generation by strong electric field ionization discharge

    International Nuclear Information System (INIS)

    Bai Mindi; Deng Shufang; Bai Xiyao; Zhang Zhitao

    2004-01-01

    Considering the change in the structure of reaction room, dielectric materials and process technology, authors have specifically studied the plasma reaction process of creating hydroxyl radical OH * and e aq - from ionization of O 2 and H 2 O through a strong electric field discharge. The production volume of hydroxyl radical OH * is up to the project application level, and process technology meets the 12 laws of green chemistry, free from environmental pollution from the source. The authors have emphatically researched on the green method of flue gas desulfurization, which will ionize SO 2 , H 2 O and O 2 in the flue gas to synthesis H 2 SO 4 in molecular level within 0.8 s without absorbent and catalyst. (author)

  13. Edge radial electric field structure in quiescent H-mode plasmas in the DIII-D tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Burrell, K H [General Atomics, PO Box 85608, San Diego, CA 92186-5608 (United States); West, W P [General Atomics, PO Box 85608, San Diego, CA 92186-5608 (United States); Doyle, E J [University of California, Los Angeles, CA 90095-1597 (United States); Austin, M E [University of Texas at Austin, Austin, TX 78712 (United States); DeGrassie, J S [General Atomics, PO Box 85608, San Diego, CA 92186-5608 (United States); Gohil, P [General Atomics, PO Box 85608, San Diego, CA 92186-5608 (United States); Greenfield, C M [General Atomics, PO Box 85608, San Diego, CA 92186-5608 (United States); Groebner, R J [General Atomics, PO Box 85608, San Diego, CA 92186-5608 (United States); Jayakumar, R [Lawrence Livermore National Laboratory, Livermore, CA 94551-9900 (United States); Kaplan, D H [General Atomics, PO Box 85608, San Diego, CA 92186-5608 (United States); Lao, L L [General Atomics, PO Box 85608, San Diego, CA 92186-5608 (United States); Leonard, A W [General Atomics, PO Box 85608, San Diego, CA 92186-5608 (United States); Makowski, M A [Lawrence Livermore National Laboratory, Livermore, CA 94551-9900 (United States); McKee, G R [University of Wisconsin, Madison, WI 53706-1687 (United States); Solomon, W M [Princeton Plasma Physics Laboratory, Princeton, NJ 08543-0451 (United States); Thomas, D M [General Atomics, PO Box 85608, San Diego, CA 92186-5608 (United States); Rhodes, T L [University of California, Los Angeles, CA 90095-1597 (United States); Wade, M R [Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Wang, G [University of California, Los Angeles, CA 90095-1597 (United States); Watkins, J G [Sandia National Laboratories, Albuquerque, NM 87185 (United States); Zeng, L [University of California, Los Angeles, CA 90095-1597 (United States)

    2004-05-01

    H-mode operation is the choice for next step tokamak devices based on either conventional or advanced tokamak physics. This choice, however, comes at a significant cost for both the conventional and advanced tokamaks because of the effects of edge localized modes (ELMs). ELMs can produce significant erosion in the divertor and can affect the {beta} limit and reduced core transport regions needed for advanced tokamak operation. Experimental results from DIII-D over the past four years have demonstrated a new operating regime, the quiescent H-mode (QH-mode) regime, that solves these problems. QH-mode plasmas have now been run for over 4 s (>30 energy confinement times). Utilizing the steady-state nature of the QH-mode edge allows us to obtain unprecedented spatial resolution of the edge ion profiles and the edge radial electric field, E{sub r}, by sweeping the edge plasma slowly past the view points of the charge exchange spectroscopy system. We have investigated the effects of direct edge ion orbit loss on the creation and sustainment of the QH-mode. Direct loss of ions injected into the velocity-space loss cone at the plasma edge is not necessary for creation or sustainment of the QH-mode. The direct ion orbit loss has little effect on the edge E{sub r} well. The E{sub r} at the bottom of the well in these cases is about -100 kV m{sup -1} compared with -20 to -30 kV m{sup -1} in the standard H-mode. The well is about 1 cm wide, which is close to the diameter of the deuteron gyro-orbit. We also have investigated the effect of changing edge triangularity by changing the plasma shape from upwardly biased single null to magnetically balanced double null. We have now achieved the QH-mode in these double-null plasmas. The increased triangularity allows us to increase pedestal density in QH-mode plasmas by a factor of about 2.5 and overall pedestal pressure by a factor of 2. Pedestal {beta} and {nu}{sup *} values matching the values desired for ITER have been achieved. In

  14. Pair production in a strong electric field with back-reaction

    International Nuclear Information System (INIS)

    Eisenberg, J.M.

    1992-01-01

    A summary is presented of the current status of efforts to solve the problem in which pairs are produced in a strong electric field, are accelerated by it, and then react back on it through the counter-field produced by their current. A review of recent developments in this back-reaction problem is given. A simple version of the theory of pair tunneling from a fixed electric field, is first presented and then a sketch is provided as to how this has been applied to the quark-gluon plasma. Then I turn to a field formulation of the problem for charged bosons, which leads to the need to carry out a renormalization program, outlined again in simple terms. Numerical results for this program are presented for one and for three spatial dimensions, and the corresponding physical behaviour of the system is discussed. I exhibit a phenomenological transport equation embodying physics that is essentially identical to that of the field formulation. Lastly, I present the extension to the fermion case and to the formulation in terms of boost-invariant variables (as required for the quark-gluon plasma). 6 figs., 17 refs. (author)

  15. Runaway breakdown in strong electric field as a source of terrestrial gamma flashes and gamma bursts in lightning leader steps

    Energy Technology Data Exchange (ETDEWEB)

    Gurevich, A.V. [P.N. Lebedev Physical Institute, Russian Academy of Sciences, 119991 Moscow (Russian Federation)]. E-mail: alex@lpi.ru; Zybin, K.P. [P.N. Lebedev Physical Institute, Russian Academy of Sciences, 119991 Moscow (Russian Federation); Medvedev, Yu.V. [Joint Institute for High Temperature, Russian Academy of Sciences, 127412 Moscow (Russian Federation)

    2007-01-22

    The new model of lightning step leader is proposed. It includes three main processes developing simultaneously in a strong electric field: conventional breakdown, effect of runaway electrons and runaway breakdown (RB). The theory of RB in strong electric field is developed. Comparison with the existing observational data shows that the model can serve as a background for the explanation of gamma bursts in step leader and TGF.

  16. Runaway breakdown in strong electric field as a source of terrestrial gamma flashes and gamma bursts in lightning leader steps

    International Nuclear Information System (INIS)

    Gurevich, A.V.; Zybin, K.P.; Medvedev, Yu.V.

    2007-01-01

    The new model of lightning step leader is proposed. It includes three main processes developing simultaneously in a strong electric field: conventional breakdown, effect of runaway electrons and runaway breakdown (RB). The theory of RB in strong electric field is developed. Comparison with the existing observational data shows that the model can serve as a background for the explanation of gamma bursts in step leader and TGF

  17. Pair production in a strong electric field with back-reaction

    International Nuclear Information System (INIS)

    Eisenberg, J.M.; Kluger, Y.; Svetitsky, B.

    1992-01-01

    We present a summary of the present status of efforts to solve the problem in which pairs are produced in a strong electric field, are accelerated by it, and then react back on it through the counter-field produced by their current. This picture has been used by Bialas and Czyz and others as a model for effects that may possibly arise in the study of the quark-gluon plasma. We here give a didactic review of recent developments in this back-reaction problem. We first present a simple version of the theory of pair tunneling from a fixed electric field, and then sketch how this has been applied to the quark-gluon plasma. Then we turn to a field formulation of the problem for charged bosons, which leads to the need to carry out a renormalization program, outlined again in simple terms. Numerical results for this program are presented for one spatial dimension, the corresponding physical behaviour of the system is discussed, and the implications for three spatial dimensions are considered. We exhibit a phenomenological transport equation embodying physics that is essentially identical to that of the field formulation, thus helping to tie the model of Bialas and Czyz for the quark-gluon plasma to a field-theory formulation. Last, we note the status of extensions to the problem with three space dimensions; the fermion case; the formulation in terms of boost-invariant variables (as desirable for the quark-gluon plasma); and transport equations derived in a fundamental and consistent fashion. 5 figs., 13 refs. (author)

  18. Electrical switching of antiferromagnets via strongly spin-orbit coupled materials

    Science.gov (United States)

    Li, Xi-Lai; Duan, Xiaopeng; Semenov, Yuriy G.; Kim, Ki Wook

    2017-01-01

    Electrically controlled ultra-fast switching of an antiferromagnet (AFM) is shown to be realizable by interfacing it with a material of strong spin-orbit coupling. The proximity interaction between the sublattice magnetic moments of a layered AFM and the spin-polarized free electrons at the interface offers an efficient way to manipulate antiferromagnetic states. A quantitative analysis, using the combination with a topological insulator as an example, demonstrates highly reliable 90° and 180° rotations of AFM magnetic states under two different mechanisms of effective torque generation at the interface. The estimated switching speed and energy requirement are in the ps and aJ ranges, respectively, which are about two-three orders of magnitude better than the ferromagnetic counterparts. The observed differences in the magnetization dynamics may explain the disparate characteristic responses. Unlike the usual precessional/chiral motions in the ferromagnets, those of the AFMs can essentially be described as a damped oscillator with a more direct path. The impact of random thermal fluctuations is also examined.

  19. Reduction of ion thermal diffusivity associated with the transition of the radial electric field in neutral-beam-heated plasmas in the large helical device.

    Science.gov (United States)

    Ida, K; Funaba, H; Kado, S; Narihara, K; Tanaka, K; Takeiri, Y; Nakamura, Y; Ohyabu, N; Yamazaki, K; Yokoyama, M; Murakami, S; Ashikawa, N; deVries, P C; Emoto, M; Goto, M; Idei, H; Ikeda, K; Inagaki, S; Inoue, N; Isobe, M; Itoh, K; Kaneko, O; Kawahata, K; Khlopenkov, K; Komori, A; Kubo, S; Kumazawa, R; Liang, Y; Masuzaki, S; Minami, T; Miyazawa, J; Morisaki, T; Morita, S; Mutoh, T; Muto, S; Nagayama, Y; Nakanishi, H; Nishimura, K; Noda, N; Notake, T; Kobuchi, T; Ohdachi, S; Ohkubo, K; Oka, Y; Osakabe, M; Ozaki, T; Pavlichenko, R O; Peterson, B J; Sagara, A; Saito, K; Sakakibara, S; Sakamoto, R; Sanuki, H; Sasao, H; Sasao, M; Sato, K; Sato, M; Seki, T; Shimozuma, T; Shoji, M; Suzuki, H; Sudo, S; Tamura, N; Toi, K; Tokuzawa, T; Torii, Y; Tsumori, K; Yamamoto, T; Yamada, H; Yamada, I; Yamaguchi, S; Yamamoto, S; Yoshimura, Y; Watanabe, K Y; Watari, T; Hamada, Y; Motojima, O; Fujiwara, M

    2001-06-04

    Recent large helical device experiments revealed that the transition from ion root to electron root occurred for the first time in neutral-beam-heated discharges, where no nonthermal electrons exist. The measured values of the radial electric field were found to be in qualitative agreement with those estimated by neoclassical theory. A clear reduction of ion thermal diffusivity was observed after the mode transition from ion root to electron root as predicted by neoclassical theory when the neoclassical ion loss is more dominant than the anomalous ion loss.

  20. Application of the nuclear liquid drop model to a negative hydrogen ion in the strong electric field of a laser

    Energy Technology Data Exchange (ETDEWEB)

    Amusia, M.Ya.; Kornyushin, Y. [Racah Institute of Physics, Hebrew University, Jerusalem (Israel)]. E-mail: yurik@vms.huji.ac.il

    2000-09-01

    The nuclear liquid drop model is applied to describe some basic properties of a negative hydrogen ion in the strong electric field of a laser. The equilibrium ionic size, energy and polarizability of the ion are calculated. Collective modes of the dipole oscillations are considered. A barrier which arises in a strong electric field is studied. The barrier vanishes at some large value of the electric field, which is defined as a critical value. The dependence of the critical field on frequency is studied. At frequencies {omega}{>=}({omega}{sub d}/2{sup 1/2}) ({omega}{sub d} is the frequency of the dipole oscillations of the electronic cloud relative to the nucleus) the barrier remains for any field. At high frequencies a 'stripping' mechanism for instability arises. At the resonant frequency a rather low amplitude of the electric field causes the 'stripping' instability. (author)

  1. Role of radial electric field in LH transition triggered by counter-NBI at low plasma density in the TUMAN-3M tokamak

    International Nuclear Information System (INIS)

    Tukachinsky, A.S.; Askinazi, L.G.; Chernyshev, F.V. and others; Krupnik, L.I.; Rushkevich, A.A.

    2008-01-01

    Threshold power needed to attain H-mode in a tokamak is a critical parameter for designing of future devices and in particular fusion reactor ITER [1]. According to commonly accepted scaling [2] the threshold power P t hr increases with average density n e when the density exceeds some n em in at which P t hr is minimal. An increase in the P t hr towards low density was observed in many experiments [3-6], prevents the transition at lower n e as well. Physics of the threshold power increase at low ne is not well understood. Since the radial electric field E r and E r xB sheared flow play important roles in the LH transition one could expect these quantities effect the low n-bar e transitions. Toroidal rotation and radial electric field generation during counter-NBI have been studied in [7] and recently reconsidered theoretically in [8]. Thus, motivation for the presented study is to analyze effect of counter-NBI on the LH transition at low density

  2. Electromagnetic processes in pulsars under strong electric and magnetic field conditions

    International Nuclear Information System (INIS)

    Ayasli, S.; Hacinliyan, A.; Oegelman, H.B.; Daugherty, I.K.

    1977-01-01

    It is believed that pulsars possess huge electric and magnetic fields. However, the electric field is commonly neglected in calculations of the rate of pair production, a process which is thought to be greatly important in the radiation mechanisms of pulsars. To see the effect of the electric field, the pair production is calculated for arbitrary electric and magnetic field configurations. The formulae thus obtained are then applied to pulsars. It is shown that the correction to the ''polar gap'' height calculated in the Ruderman and Sutherland model is negligible, although it might be important for the spectrum of emerging photons. (author)

  3. A hybrid self-adaptive Particle Swarm Optimization–Genetic Algorithm–Radial Basis Function model for annual electricity demand prediction

    International Nuclear Information System (INIS)

    Yu, Shiwei; Wang, Ke; Wei, Yi-Ming

    2015-01-01

    Highlights: • A hybrid self-adaptive PSO–GA-RBF model is proposed for electricity demand prediction. • Each mixed-coding particle is composed by two coding parts of binary and real. • Five independent variables have been selected to predict future electricity consumption in Wuhan. • The proposed model has a simpler structure or higher estimating precision than other ANN models. • No matter what the scenario, the electricity consumption of Wuhan will grow rapidly. - Abstract: The present study proposes a hybrid Particle Swarm Optimization and Genetic Algorithm optimized Radial Basis Function (PSO–GA-RBF) neural network for prediction of annual electricity demand. In the model, each mixed-coding particle (or chromosome) is composed of two coding parts, binary and real, which optimizes the structure of the RBF by GA operation and the parameters of the basis and weights by a PSO–GA implementation. Five independent variables have been selected to predict future electricity consumption in Wuhan by using optimized networks. The results shows that (1) the proposed PSO–GA-RBF model has a simpler network structure (fewer hidden neurons) or higher estimation precision than other selected ANN models; and (2) no matter what the scenario, the electricity consumption of Wuhan will grow rapidly at average annual growth rates of about 9.7–11.5%. By 2020, the electricity demand in the planning scenario, the highest among the scenarios, will be 95.85 billion kW h. The lowest demand is estimated for the business-as-usual scenario, and will be 88.45 billion kW h

  4. Collisional ionization of Na by HBr in weak to strong electric fields

    International Nuclear Information System (INIS)

    Safinya, K.A.; Gallagher, T.F.; Sandner, W.; Gounand, F.

    1985-01-01

    We report the effect of static electric fields on the collisional ionization of highly excited sodium atoms by HBr. The binding energy dependence of the collisional ionization cross section is measured at zero field and in static electric fields up to that point at which the atom field ionizes. The applied electric field lowers the ionization threshold of the atom from its zero field value. Therefore an atom near the ionization threshold in an electric field is of smaller size than a free field atom with the same binding energy. Thus measuring the binding energy dependence of the cross section at different values of the electric field allows us to study the effects of the physical size of the atom on the cross section. The effect of the electric field was to lower the measured ionization cross section. However, the binding energy dependence of the cross section remains unchanged at the level of our measurement accuracy. The measured cross sections are larger for larger atoms, exhibit a drop with increasing binding energy characteristic of rotational to electronic excitation transfer, and are of order 10 -12 --10 -11 cm 2 . A simple calculation based on dipole (J→ J-1) excitation transfer from the molecule to the atom predicts, with good agreement, the binding energy dependence of the cross section. The electric field dependence of the data however, is not shown in the theory

  5. Electrical Control of Structural and Physical Properties via Strong Spin-Orbit Interactions in Sr2IrO4

    Science.gov (United States)

    Cao, G.; Terzic, J.; Zhao, H. D.; Zheng, H.; De Long, L. E.; Riseborough, Peter S.

    2018-01-01

    Electrical control of structural and physical properties is a long-sought, but elusive goal of contemporary science and technology. We demonstrate that a combination of strong spin-orbit interactions (SOI) and a canted antiferromagnetic Mott state is sufficient to attain that goal. The antiferromagnetic insulator Sr2IrO4 provides a model system in which strong SOI lock canted Ir magnetic moments to IrO6 octahedra, causing them to rigidly rotate together. A novel coupling between an applied electrical current and the canting angle reduces the Néel temperature and drives a large, nonlinear lattice expansion that closely tracks the magnetization, increases the electron mobility, and precipitates a unique resistive switching effect. Our observations open new avenues for understanding fundamental physics driven by strong SOI in condensed matter, and provide a new paradigm for functional materials and devices.

  6. Operating cost minimization of a radial distribution system in a deregulated electricity market through reconfiguration using NSGA method

    International Nuclear Information System (INIS)

    Chandramohan, S.; Atturulu, Naresh; Devi, R.P. Kumudini; Venkatesh, B.

    2010-01-01

    In the future, mechanisms for trade in ancillary services such as reactive power will be implemented in many deregulated power systems. In such an operating framework, a Distribution Corporation (DisCo) would have to purchase reactive power along with real power from the connected transmission corporation. A DisCo would want to minimize its operating costs by minimizing the total amount of real and reactive power drawn from the connected transmission system. Optimally reconfiguring the network will achieve such a goal. In this work, we use a non-dominated sorting genetic algorithm (NSGA) for reconfiguring a radial DisCo to minimize its operating costs considering real and reactive power costs while maximizing its operating reliability and satisfying the regular operating constraints. This method is tested on sample test systems and reported. (author)

  7. A few more comments on secularly growing loop corrections in strong electric fields

    International Nuclear Information System (INIS)

    Akhmedov, E.T.; Popov, F.K.

    2015-01-01

    We extend the observations of our previous paper http://dx.doi.org/10.1007/JHEP09(2014)071 [http://arxiv.org/abs/1405.5285]. particular, we show that the secular growth of the loop corrections to the two-point correlation functions is gauge independent: we observe the same growth in the case of the static gauge for the constant background electric field. Furthermore we solve the kinetic equation describing photon production from the background fields, which was derived in our previous paper and allows one to sum up leading secularly growing corrections from all loops. Finally, we show that in the constant electric field background the one-loop correction to the current of the produced pairs is not zero: it also grows with time and violates time translational and reversal invariance of QED on the constant electric field background.

  8. The role of the radial electric field in confinement and transport in H-mode and VH-mode discharges in the DIII-D tokamak

    International Nuclear Information System (INIS)

    Gohil, P.; Burrell, K.H.; Groebner, R.J.; Osborne, T.H.; Doyle, E.J.; Rettig, C.L.

    1993-08-01

    Measurements of the radial electric field, E r , with high spatial and high time resolution in H-mode and VH-mode discharges in the DIII-D tokamak have revealed the significant influence of the shear in E r on confinement and transport in these discharges. These measurements are made using the DIII-D Charge Exchange Recombination (CER) System. At the L-H transition in DIII-D plasmas, a negative well-like E r profile develops just within the magnetic separatrix. A region of shear in E r results, which extends 1 to 2 cm into the plasma from the separatrix. At the transition, this region of sheared E r exhibits the greatest increase in impurity ion poloidal rotation velocity and the greatest reduction in plasma fluctuations. A transport barrier is formed in this same region of E x B velocity shear as is signified by large increases in the observed gradients of the ion temperature, the carbon density, the electron temperature and electron density. The development of the region of sheared E r , the increase in impurity ion poloidal rotation, the reduction in plasma turbulence, and the transport barrier all occur simultaneously at the L-H transition. Measurements of the radial electric field, plasma turbulence, thermal transport, and energy confinement have been performed for a wide range of plasma conditions and configurations. The results support the supposition that the progression of improving confinement at the L-H transition, into the H-mode and then into the VH-mode can be explained by the hypothesis of the suppression of plasma turbulence by the increasing penetration of the region of sheared E x B velocity into the plasma interior

  9. Strong dopant dependence of electric transport in ion-gated MoS2

    NARCIS (Netherlands)

    Piatti, Erik; Chen, Qihong; Ye, Jianting

    2017-01-01

    We report modifications of the temperature-dependent transport properties of MoS2 thin flakes via field-driven ion intercalation in an electric double layer transistor. We find that intercalation with Li+ ions induces the onset of an inhomogeneous superconducting state. Intercalation with K+ leads

  10. The Vlasov equation with strong magnetic field and oscillating electric field as a model for isotop resonant separation

    Directory of Open Access Journals (Sweden)

    Emmanuel Frenod

    2002-01-01

    Full Text Available We study the qualitative behavior of solutions to the Vlasov equation with strong external magnetic field and oscillating electric field. This model is relevant to the understanding of isotop resonant separation. We show that the effective equation is a kinetic equation with a memory term. This memory term involves a pseudo-differential operator whose kernel is characterized by an integral equation involving Bessel functions. The kernel is explicitly given in some particular cases.

  11. Properties of epitaxial films of indium phosphides alloyed with erbium in strong electric fields

    International Nuclear Information System (INIS)

    Borisov, V.I.; Dvoryankin, V.F.; Korobkin, V.A.; Kudryashov, A.A.; Lopatin, V.V.; Lyubchenko, V.E.; Telegin, A.A.

    1986-01-01

    Temperature dependences of specific resistance and free charge-carrier mobility at low temperatures for indium phosphide films grown by liquid-phase epitaxial method with erbium additions (0.01-0.1 mass%). The main mechanisms of scattering for different temperature regions: scattering on ionized impurities in the rage from 20 to 40 K and lattice scattering at the temperature above 90 K are determined. The current density dependences on applied electric field strength are presented

  12. Optical pulling and pushing forces exerted on silicon nanospheres with strong coherent interaction between electric and magnetic resonances.

    Science.gov (United States)

    Liu, Hongfeng; Panmai, Mingcheng; Peng, Yuanyuan; Lan, Sheng

    2017-05-29

    We investigated theoretically and numerically the optical pulling and pushing forces acting on silicon (Si) nanospheres (NSs) with strong coherent interaction between electric and magnetic resonances. We examined the optical pulling and pushing forces exerted on Si NSs by two interfering waves and revealed the underlying physical mechanism from the viewpoint of electric- and magnetic-dipole manipulation. As compared with a polystyrene (PS) NS, it was found that the optical pulling force for a Si NS with the same size is enlarged by nearly two orders of magnitude. In addition to the optical pulling force appearing at the long-wavelength side of the magnetic dipole resonance, very large optical pushing force is observed at the magnetic quadrupole resonance. The correlation between the optical pulling/pushing force and the directional scattering characterized by the ratio of the forward to backward scattering was revealed. More interestingly, it was found that the high-order electric and magnetic resonances in large Si NSs play an important role in producing optical pulling force which can be generated by not only s-polarized wave but also p-polarized one. Our finding indicates that the strong coherent interaction between the electric and magnetic resonances existing in nanoparticles with large refractive indices can be exploited to manipulate the optical force acting on them and the correlation between the optical force and the directional scattering can be used as guidance. The engineering and manipulation of optical forces will find potential applications in the trapping, transport and sorting of nanoparticles.

  13. A strong argument for using non-commodities to generate electricity

    International Nuclear Information System (INIS)

    Santiago, Katarina Tatiana Marques; Campello de Souza, Fernando Menezes; Carvalho Bezerra, Diogo de

    2014-01-01

    An optimal control approach towards generating electricity is used to analyze the trade-off between using of primary sources which are regarded as commodities, such as fossil fuels, biomass and water to generate electricity, and exploiting these sources for their other economic uses (for example, in the petrochemical industry, in the production of fuels, in agriculture, in steelmaking, and so forth). In order to do so, a dynamic model is presented which establishes relationships between economic growth, the fossil fuel, water and biomass sectors, and energy policies, based on the application of the Pontryagin Maximum Principle. Among other results, the analysis establishes that, under the optimal path, the price of commodities for non-energy uses should be twice the price of the energy assets. This indicates that sources which are not commodities such as solar energy, wind energy, and geothermal energy, should be used to generate electricity. - Highlights: • We used an optimal control approach to analyze the trade-off between the multiple uses of energy resource. • We used a dynamic model which establishes relationships between economic growth, the fossil fuel, water and biomass sectors. • The analysis establishes that the price of commodities for non-energy uses should be twice the price of the energy assets

  14. High-latitude dayside electric fields and currents during strong northward interplanetary magnetic field: Observations and model simulation

    International Nuclear Information System (INIS)

    Clauer, C.R.; Friis-Christensen, E.

    1988-01-01

    On July 23, 1983, the Interplanetary Magnetic Field turned strongly northward, becoming about 22 nT for several hours. Using a combined data set of ionospheric convection measurements made by the Sondre Stromfjord incoherent scatter radar and convection inferred from Greenland magnetometer measurements, we observe the onset of the reconfiguration of the high-latitude ionospheric currents to occur about 3 min following the northward IMF encountering the magnetopause. The large-scale reconfiguration of currents, however, appears to evolve over a period of about 22 min. Using a computer model in which the distribution of field-aligned current in the polar cleft is directly determined by the strength and orientation of the interplanetary electric field, we are able to simulate the time-varying pattern of ionospheric convection, including the onset of high-latitude ''reversed convection'' cells observed to form during the interval of strong northward IMF. These observations and the simulation results indicate that the dayside polar cap electric field observed during strong northward IMF is produced by a direct electrical current coupling with the solar wind. copyright American Geophysical Union 1988

  15. Divertor experiments in a toroidal plasma, with E x B drift due to an applied radial electric field

    International Nuclear Information System (INIS)

    Strait, E.J.

    1979-09-01

    It is proposed that the E x B drift arising from an externally applied electric field could be used in a tokamak or other toroidal magnetic plasma confinement device to remove plasma and impurities from the region near the wall and reduce the amount of plasma striking the wall. This could either augment or replace a conventional magnetic field divertor. Among the possible advantages of this scheme are easy external control over the rate of removal of plasma, more rapid removal than the naturally occurring rate in a magnetic divertor, and simplification of construction if the magnetic divertor is eliminated. Results of several related experiments performed in the Wisconsin Levitated Octupole are presented

  16. Radially and temporally resolved electric field of positive streamers in air and modelling of the induced plasma chemistry

    Czech Academy of Sciences Publication Activity Database

    Hoder, T.; Šimek, Milan; Bonaventura, Z.; Prukner, Václav; Gordillo-Vázquez, F.J.

    2016-01-01

    Roč. 25, č. 4 (2016), č. článku 045021. ISSN 0963-0252 R&D Projects: GA ČR(CZ) GA15-04023S Grant - others:Rada Programu interní podpory projektů mezinárodní spolupráce AV ČR(CZ) M100431201 Program:M Institutional support: RVO:61389021 Keywords : streamer * electric field * Blue Jet * air plasma chemistry * transient luminous event Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 3.302, year: 2016 http://iopscience.iop.org/article/10.1088/0963-0252/25/4/045021/meta

  17. The importance of the radial electric field (Er) on interpretation of motional Stark effect measurements of the q profile in DIII-D high performance plasmas

    International Nuclear Information System (INIS)

    Rice, B.W.; Lao, L.L.; Burrell, K.H.; Greenfield, C.M.; Lin-Liu, Y.R.

    1997-06-01

    The development of enhanced confinement regimes such as negative central magnetic shear (NCS) and VH-mode illustrates the importance of the q profile and ExB velocity shear in improving stability and confinement in tokamak plasmas. Recently, it was realized that the large values of radial electric field observed in these high performance plasmas, up to 200 kV/m in DIII-D, have an effect on the interpretation of motional Stark effect (MSE) measurements of the q profile. It has also been shown that, with additional MSE measurements, one can extract a direct measurement of E r in addition to the usual poloidal field measurement. During a recent vent on DIII-D, 19 additional MSE channels with new viewing angles were added (for a total of 35 channels) in order to descriminate between the neutral beam v b x B electric field and the plasma E r field. In this paper, the system upgrade will be described and initial measurements demonstrating simultaneous measurement of the q and E r profiles will be presented

  18. The odd Voigt effect under a strong electric field in semiconductors

    International Nuclear Information System (INIS)

    Nguyen Hong Shon.

    1991-08-01

    The high frequency conductivity tensor σ ik (ω) in the linear approximation of magnetic field H and in the quadratic approximation of external dc electric field is derived by solving Boltzmann equation. The magneto-optical phenomena in the Voigt configuration (when a probe electro-magnetic wave propagates across a magnetic field) are investigated. It is shown that the birefringence and dichroism have a component that is odd (linear) in the magnetic fields and predominate over the even effect in the weak magnetic field. (author). 8 refs

  19. Motion of Rydberg atoms with strong permanent-electric-dipole interactions

    International Nuclear Information System (INIS)

    Gonçalves, Luís Felipe; Thaicharoen, Nithiwadee; Raithel, Georg

    2016-01-01

    Using classical trajectories simulations, we investigate the dynamics of a cold sample of Rydberg atoms with high permanent electric dipole moments. The dipolar state can be created using an adiabatic passage through an avoided crossing between an S-like state and a linear Stark state. The simulations yield the pair-correlation functions (PCF) of the atom samples, which allow us to extract the motion of Rydberg-atom pairs in the many-body system. The results reveal the strength and the anisotropic character of the underlying interaction. The simulation is employed to test the suitability of experimental methods designed to derive interaction parameters from PCF. Insight is obtained about the stability of the method against variation of experimentally relevant parameters. Transient correlations due to interaction-induced heating are observed. (paper)

  20. Cytogenetic characterization of the strongly electric Amazonian eel, Electrophorus electricus (Teleostei, Gymnotiformes, from the Brazilian rivers Amazon and Araguaia

    Directory of Open Access Journals (Sweden)

    Soraia B.A. Fonteles

    2008-01-01

    Full Text Available A karyotype analysis of the electric eel, Electrophorus electricus (Teleostei, Gymnotiformes, a strongly electric fish from northern South America, is presented. Two female specimens were analyzed, one from the Amazon River and one from the Araguaia River. The specimens had a chromosomal number of 2n = 52 (42M-SM + 10A. C-bands were present in a centromeric and pericentromeric position on part of the chromosomes; some interstitial C-bands were also present. Heteromorphic nucleolus organizer regions (NORs were detected in two chromosome pairs of the specimen from the Amazon River. The chromosome number and karyotype characteristics are similar to those of other Gymnotidae species. The genera Electrophorus and Gymnotus are positioned as the basal lineages in the Gymnotiformes phylogeny.

  1. Observation of the Avalanche of Runaway Electrons in Air in a Strong Electric Field

    Science.gov (United States)

    Gurevich, A. V.; Mesyats, G. A.; Zybin, K. P.; Yalandin, M. I.; Reutova, A. G.; Shpak, V. G.; Shunailov, S. A.

    2012-08-01

    The generation of an avalanche of runaway electrons is demonstrated for the first time in a laboratory experiment. Two flows of runaway electrons are formed sequentially in an extended air discharge gap at the stage of delay of a pulsed breakdown. The first, picosecond, runaway electron flow is emitted in the cathode region where the field is enhanced. Being accelerated in the gap, this beam generates electrons due to impact ionization. These secondary electrons form a delayed avalanche of runaway electrons if the field is strong enough. The properties of the avalanche correspond to the existing notions about the runaway breakdown in air. The measured current of the avalanche exceeds up to an order the current of the initiating electron beam.

  2. Methanol and ethanol vapor conversion in gas discharge with strongly non-uniform distribution of electric field on atmospheric pressure

    International Nuclear Information System (INIS)

    Golota, V.I.; Zavada, L.M.; Kotyukov, O.V.; Kudin, D.V.; Rodionov, S.V.; Pis'menetskoj, A.S.; Dotsenko, Yu.V.

    2010-01-01

    The barrierless gas discharge of negative polarity with strongly non-uniform distribution of electrical field in the methanol and ethanol vapour was studied. It is shown that level of methanol and ethanol conversion depended from power consumed by the discharge and exposition time for gas mixture in discharge zone. The condition for deep conversion of the methanol and ethanol vapours were determined. The water and carbon dioxide are the end products for the methanol and ethanol conversion. Formaldehyde and formic acid are the intermediates products in the conversion of methanol. And ethanol has a number of different compounds, including acetic acid, acetaldehyde, etc.

  3. Neonatal thalamic hemorrhage is strongly associated with electrical status epilepticus in slow wave sleep.

    Science.gov (United States)

    Kersbergen, Karina J; de Vries, Linda S; Leijten, Frans S S; Braun, Kees P J; Nievelstein, Rutger A J; Groenendaal, Floris; Benders, Manon J N L; Jansen, Floor E

    2013-04-01

    Thalamic hemorrhage has been associated with neonatal cerebral sinovenous thrombosis (CSVT), especially when the straight sinus is involved, and often presents with neonatal seizures. Early thalamic injury has previously been shown to predispose to epilepsy and electrical status epilepticus in slow wave sleep (ESES). The objective of this study was to assess the prevalence of sleep-induced epileptic electroencephalography (EEG) abnormalities and postneonatal epilepsy after neonatal thalamic hemorrhage associated with CSVT, in the absence of more widespread cerebral damage. Between 2003 and 2008 15 neonates were diagnosed with a thalamic hemorrhage due to suspected or proven CSVT. Neurodevelopment and the history of seizures were assessed at follow-up in the outpatient clinic in all 14 survivors (age 2-9 years). Whole-night or sleep-deprived EEG recordings were obtained to assess the prevalence of interictal epileptiform activity (EA) and calculate a sleep-induced spike and wave index (SWI). Three children were diagnosed with classic ESES (SWI >85%). Two children had ESES spectrum disorder (SWI between 50% and 85%), and in two children significant sleep-induced epileptiform activity (SIEA) was noted (SWI between 25% and 50%). Two other children were diagnosed with focal epilepsy, in the absence of sleep-induced epileptiform EEG abnormalities. Five children (age 2-7 years) had normal EEG recordings at follow-up. Deficits in neurodevelopment were seen significantly more often in children with ESES, ESES spectrum, or SIEA. Neonates with thalamic hemorrhage associated with straight sinus thrombosis, without evidence of more widespread cerebral damage, are at high risk of developing ESES (spectrum) disorder (35%), SIEA (14%), or focal epilepsy (14%). Electrographic abnormalities may already be present prior to recognition of cognitive deficits. Early diagnosis may guide parents and caregivers, and subsequent treatment may improve neurodevelopmental outcome. Routine

  4. Quantum electrodynamics at strong electric fields. The ground state Lamb shift in hydrogenlike uranium

    Energy Technology Data Exchange (ETDEWEB)

    Gumberidze, A.; Stoehlker, T. [Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (Germany)]|[Frankfurt Univ. (Germany). Inst. fuer Kernphysik; Banas, D. [Pedagogical Univ., Kielce (PL). Inst. of Phys.] [and others

    2005-05-01

    X-ray spectra following radiative recombination of free electrons with bare uranium ions (U{sup 92+}) were measured at the electron cooler of the ESR storage ring. The most intense lines observed in the spectra can be attributed to the characteristic Lyman ground-state transitions and to the recombination of free electrons into the K-shell of the ions. Our experiment was carried out by utilizing the deceleration technique which leads to a considerable reduction of the uncertainties associated with Doppler corrections. This, in combination with the 0 observation geometry, allowed us to determine the ground-state Lamb shift in hydrogen-like uranium (U{sup 91+}) from the observed X-ray lines with an accuracy of 1%. The present result is about 3 times more precise than the most accurate value available up to now and provides the most stringent test of bound-state quantum electrodynamics for one-electron systems in the strong-field regime. (orig.)

  5. Stabilization effect of a strong HF electrical field on beam-plasma interaction in a relativistic plasma waveguide

    International Nuclear Information System (INIS)

    El-Shorbagy, K.H.

    2000-07-01

    The influence effect of a strong HF electrical field on the excitation of surface waves by an electron beam under the development of instability of low-density electron beam passing through plane relativistic plasma is investigated. Starting from the two fluid plasma model we separate the problem into two parts. The 'temporal' (dynamical) part enables us to find the frequencies and growth rates of unstable waves. This part within the redefinition of natural (eigen) frequencies coincide with the system describing HF suppression of the Buneman instability in a uniform unbounded plasma. Natural frequencies of oscillations and spatial distribution of the amplitude of the self-consistent electrical field are obtained by solving a boundary value problem ('spatial' part) considering a specific spatial distribution of plasma density. Plasma electrons are considered to have a relativistic velocity. It is shown that a HF electric field has no essential influence on dispersion characteristics of unstable surface waves excited in a relativistic plasma waveguide by a low-density electron beam. The region of instability only slightly narrowing and the growth rate decreases by a small parameter and this result has been reduced compared to nonrelativistic plasma. Also, it is found that the plasma electrons have not affected the solution of the space part of the problem. (author)

  6. Radial Field Piezoelectric Diaphragms

    Science.gov (United States)

    Bryant, R. G.; Effinger, R. T., IV; Copeland, B. M., Jr.

    2002-01-01

    A series of active piezoelectric diaphragms were fabricated and patterned with several geometrically defined Inter-Circulating Electrodes "ICE" and Interdigitated Ring Electrodes "ICE". When a voltage potential is applied to the electrodes, the result is a radially distributed electric field that mechanically strains the piezoceramic along the Z-axis (perpendicular to the applied electric field). Unlike other piezoelectric bender actuators, these Radial Field Diaphragms (RFDs) strain concentrically yet afford high displacements (several times that of the equivalent Unimorph) while maintaining a constant circumference. One of the more intriguing aspects is that the radial strain field reverses itself along the radius of the RFD while the tangential strain remains relatively constant. The result is a Z-deflection that has a conical profile. This paper covers the fabrication and characterization of the 5 cm. (2 in.) diaphragms as a function of poling field strength, ceramic thickness, electrode type and line spacing, as well as the surface topography, the resulting strain field and displacement as a function of applied voltage at low frequencies. The unique features of these RFDs include the ability to be clamped about their perimeter with little or no change in displacement, the environmentally insulated packaging, and a highly repeatable fabrication process that uses commodity materials.

  7. A novel solution to the Klein–Gordon equation in the presence of a strong rotating electric field

    Directory of Open Access Journals (Sweden)

    E. Raicher

    2015-11-01

    Full Text Available The Klein–Gordon equation in the presence of a strong electric field, taking the form of the Mathieu equation, is studied. A novel analytical solution is derived for particles whose asymptotic energy is much lower or much higher than the electromagnetic field amplitude. The condition for which the new solution recovers the familiar Volkov wavefunction naturally follows. When not satisfied, significant deviation from the Volkov wavefunction is demonstrated. The new condition is shown to differ by orders of magnitudes from the commonly used one. As this equation describes (neglecting spin effects the emission processes and the particle motion in Quantum Electrodynamics (QED cascades, our results suggest that the standard theoretical approach towards this phenomenon should be revised.

  8. A novel solution to the Klein–Gordon equation in the presence of a strong rotating electric field

    Energy Technology Data Exchange (ETDEWEB)

    Raicher, E., E-mail: erez.raicher@mail.huji.ac.il [Racah Institute of Physics, Hebrew University, Jerusalem 91904 (Israel); Department of Applied Physics, Soreq Nuclear Research Center, Yavne 81800 (Israel); Eliezer, S. [Department of Applied Physics, Soreq Nuclear Research Center, Yavne 81800 (Israel); Nuclear Fusion Institute, Polytechnic University of Madrid, Madrid (Spain); Zigler, A. [Racah Institute of Physics, Hebrew University, Jerusalem 91904 (Israel)

    2015-11-12

    The Klein–Gordon equation in the presence of a strong electric field, taking the form of the Mathieu equation, is studied. A novel analytical solution is derived for particles whose asymptotic energy is much lower or much higher than the electromagnetic field amplitude. The condition for which the new solution recovers the familiar Volkov wavefunction naturally follows. When not satisfied, significant deviation from the Volkov wavefunction is demonstrated. The new condition is shown to differ by orders of magnitudes from the commonly used one. As this equation describes (neglecting spin effects) the emission processes and the particle motion in Quantum Electrodynamics (QED) cascades, our results suggest that the standard theoretical approach towards this phenomenon should be revised.

  9. The Impact of Strong Climate Change on Inter-state Balancing in a Fully-renewable Simplified European Electricity System

    Science.gov (United States)

    Wohland, Jan; Witthaut, Dirk

    2017-04-01

    Electricity systems with a high penetration of renewables are strongly affected by weather patterns. Due to the variability of the climate system, a substantial fraction of energy supply needs to be provided by dispatchable power plants even if the consumption is on average balanced by renewables (e.g. Rodriguez et al. [2014]). In an interconnected system like the European electricity grid, benefits can arise from balancing generation mismatches spatially as long as overproduction in one region coincides with lack of generation in another region. These benefits might change as the climate changes and we thus investigate alterations of correlations between wind timeseries and Backup energy requirements. Our analysis is based on a five member model-ensemble from the EUROCORDEX initiative and we focus on onshore wind energy. We use the highest temporal (3h) and spatial (0.11°) resolution available to capture the intermittent and spatially diverse nature of renewable generation. In view of inter-model spread and other uncertainties, we use the strong climate change scenario rcp8.5 in order to obtain a high signal-to-noise ratio. We argue that rcp8.5 is best suited to reveal interesting interactions between climate change and renewable electricity system despite the fact that is in contradiction to the UNFCCC temperature goals (e.g. Schleussner et al. [2016]). We report spatially inhomogeneous alterations of correlations. In particular, we find increasing correlations between central and northern European states and decreasing correlations at the south-western and south-eastern margins of Europe. This hints to a lowering of balancing potentials within central and northern Europe due to climate change. A possible explanation might be associated to polar amplification and increasing frequencies of blocking events (Coumou [2015]). Moreover, we compute wind energy generation using a single-turbine model and a semi-random deployment procedure as developed in Monforti et al

  10. Spontaneous electromagnetic emission from a strongly localized plasma flow.

    Science.gov (United States)

    Tejero, E M; Amatucci, W E; Ganguli, G; Cothran, C D; Crabtree, C; Thomas, E

    2011-05-06

    Laboratory observations of electromagnetic ion-cyclotron waves generated by a localized transverse dc electric field are reported. Experiments indicate that these waves result from a strong E×B flow inhomogeneity in a mildly collisional plasma with subcritical magnetic field-aligned current. The wave amplitude scales with the magnitude of the applied radial dc electric field. The electromagnetic signatures become stronger with increasing plasma β, and the radial extent of the power is larger than that of the electrostatic counterpart. Near-Earth space weather implications of the results are discussed.

  11. Radial nerve dysfunction

    Science.gov (United States)

    Neuropathy - radial nerve; Radial nerve palsy; Mononeuropathy ... Damage to one nerve group, such as the radial nerve, is called mononeuropathy . Mononeuropathy means there is damage to a single nerve. Both ...

  12. Strongly transverse-electric-polarized emission from deep ultraviolet AlGaN quantum well light emitting diodes

    Energy Technology Data Exchange (ETDEWEB)

    Reich, Christoph, E-mail: Christoph.Reich@tu-berlin.de; Guttmann, Martin; Wernicke, Tim; Mehnke, Frank; Kuhn, Christian [Institut für Festkörperphysik, Technische Universität Berlin, Hardenbergstr. 36, Berlin 10623 (Germany); Feneberg, Martin; Goldhahn, Rüdiger [Institut für Experimentelle Physik, Otto-von-Guericke-Universität, Universitätsplatz 2, Magdeburg 39106 (Germany); Rass, Jens; Kneissl, Michael [Institut für Festkörperphysik, Technische Universität Berlin, Hardenbergstr. 36, Berlin 10623 (Germany); Ferdinand-Braun-Institut, Leibniz-Institut für Höchstfrequenztechnik, Gustav-Kirchhoff-Str. 4, Berlin 12489 (Germany); Lapeyrade, Mickael; Einfeldt, Sven; Knauer, Arne; Kueller, Viola; Weyers, Markus [Ferdinand-Braun-Institut, Leibniz-Institut für Höchstfrequenztechnik, Gustav-Kirchhoff-Str. 4, Berlin 12489 (Germany)

    2015-10-05

    The optical polarization of emission from ultraviolet (UV) light emitting diodes (LEDs) based on (0001)-oriented Al{sub x}Ga{sub 1−x}N multiple quantum wells (MQWs) has been studied by simulations and electroluminescence measurements. With increasing aluminum mole fraction in the quantum well x, the in-plane intensity of transverse-electric (TE) polarized light decreases relative to that of the transverse-magnetic polarized light, attributed to a reordering of the valence bands in Al{sub x}Ga{sub 1−x}N. Using k ⋅ p theoretical model calculations, the AlGaN MQW active region design has been optimized, yielding increased TE polarization and thus higher extraction efficiency for bottom-emitting LEDs in the deep UV spectral range. Using (i) narrow quantum wells, (ii) barriers with high aluminum mole fractions, and (iii) compressive growth on patterned aluminum nitride sapphire templates, strongly TE-polarized emission was observed at wavelengths as short as 239 nm.

  13. The electrical properties of a strongly disordered system based on lightly doped germanium compensated by disordered regions

    International Nuclear Information System (INIS)

    Evseev, V.A.; Konopleva, R.F.; Yuferev, A.A.

    1976-01-01

    A study was made of lightly doped (Nsub(Sb) approximately 10 15 cm -3 ) n-Ge, heavily compensated (K = Nsub(A)/N sub(D) approximately 1) by fast neutrons from a reactor. Irradiation is shown to produce, near n-p conversion (annealing has the same effect near p-n conversion), a random relief of electrostatic potential which is caused by the overlap of the space-charge regions surrounding disordered regions (DR). the random potential field results in a spatial 'bending' of the whole band spectrum of germanium, similar to the way it is observed in amorphous semiconductors because of their disorder. Experiments show the conduction in the DR overlap region to be of an activated nature, associated with the ejection of carriers to the corresponding 'percolation' levels. The activation energy of such conduction varies with the degree of compensation. The shift of the Fermi level depends on the degree of compensation here in a much more sensitive way than in the case of compensation by chemical impurities. The properties of Ge obtained by DR overlap and by compensation with chemical impurities are compared. A superlinear I-V characteristic producing the switching effect is observed in strong electric fields (E approximately 10 3 V cm -1 ). A suggestion is made that a study of disordered systems, based on lightly doped germanium which is compensated with DRs produced by high-energy particles, should both help to obtain new information on the parameters of the DRs proper and help to simulate the properties of the amorphous semiconductors. (author)

  14. Vortex Whistle in Radial Intake

    National Research Council Canada - National Science Library

    Tse, Man-Chun

    2004-01-01

    In a radial-to-axial intake with inlet guide vanes (IGV) at the entry, a strong flow circulation Gamma can be generated from the tangential flow components created by the IGVs when their setting exceed about halfclosing (approx. 45 deg...

  15. Self-consistent radial sheath

    International Nuclear Information System (INIS)

    Hazeltine, R.D.

    1988-12-01

    The boundary layer arising in the radial vicinity of a tokamak limiter is examined, with special reference to the TEXT tokamak. It is shown that sheath structure depends upon the self-consistent effects of ion guiding-center orbit modification, as well as the radial variation of E /times/ B-induced toroidal rotation. Reasonable agreement with experiment is obtained from an idealized model which, however simplified, preserves such self-consistent effects. It is argued that the radial sheath, which occurs whenever confining magnetic field-lines lie in the plasma boundary surface, is an object of some intrinsic interest. It differs from the more familiar axial sheath because magnetized charges respond very differently to parallel and perpendicular electric fields. 11 refs., 1 fig

  16. Effect of gases and particulate matter from electricity generation process on the radial growth of teak plantations surrounding Mae Moh power plant, Lampang province

    Directory of Open Access Journals (Sweden)

    Narapong Sangram

    2016-03-01

    Full Text Available The objectives of this study were to investigate radial growth patterns and influences of polluting gases and particulate matter on the radial growth of teak plantations surrounding the Mae Moh Power Plant. Twenty-four 32-year-old teak trees were selected from Mae Jang and Mae Moh plantations, which were 5 km and 15 km from the Mae Moe power plant, respectively. Forty-eight sample cores were collected from the 24 trees (two cores per tree. The growth patterns of all the cores were analyzed following the standard methods of dendrochronology. The relationships between the growth pattern and the amounts of sulfur dioxide, nitrogen dioxide, carbon monoxide and particulate matter were measured as average daily rates and then analyzed. The study showed that the best-fit model for the relationship between the radial current annual increment at breast height (CAIdbh and time (Y was an exponential equation. The fitted equations were: CAIdbh = 10.657e(−0.031Y for Mae Moh plantation and CAIdbh = 12.518e(−0.032Y for Mae Jang plantation. The coefficient of determination for the fitted equations was 0.410 and 0.423 for the Mae Moh and Mae Jang plantations, respectively. Moreover, carbon monoxide (CO and sulfur dioxide (SO2 had a statistically significant effect on radial teak growth (RT in the Mae Jang plantation, with a coefficient of determination of 0.69 (RTmj = 0.571 + 0.429(CO − 0.023(SO2.

  17. Phonon-assisted hopping of an electron on a Wannier-Stark ladder in a strong electric field

    International Nuclear Information System (INIS)

    Emin, D.; Hart, C.F.

    1987-01-01

    With the application of a spatially constant electric field, the degeneracy of electronic energy levels of geometrically equivalent sites of a crystal is generally lifted. As a result, the electric field causes the electronic eigenstates of a one-dimensional periodic chain to become localized. In particular, they are Wannier-Stark states. With sufficiently large electric-field strengths these states become sufficiently well localized that it becomes appropriate to consider electronic transport to occur via a succession of phonon-assisted hops between the localized Wannier-Stark states. In this paper, we present calculations of the drift velocity arising from acoustic- and optical-phonon-assisted hopping motion between Wannier-Stark states. When the intersite electronic transfer energy is sufficiently small so that the Wannier-Stark states are essentially each confined to a single atomic site, the transport reduces to that of a small polaron. In this regime, while the drift velocity initially rises with increasing electric field strength, the drift velocity ultimately falls with increasing electric-field strength at extremely large electric fields. More generally, for common values of the electronic bandwidth and electric field strength, the Wannier-Stark states span many sites. At sufficiently large electric fields, the energy separation between Wannier-Stark states exceeds the energy uncertainty associated with the carrier's interaction with phonons. Then, it is appropriate to treat the electronic transport in terms of phonon-assisted hopping between Wannier-Stark states. The resulting high-field drift velocity falls with increasing field strength in a series of steps. Thus, we find a structured negative differential mobility at large electric fields

  18. Degradation of AlGaN/GaN High Electron Mobility Transistors with Different AlGaN Layer Thicknesses under Strong Electric Field

    International Nuclear Information System (INIS)

    Ling, Yang; Yue, Hao; Xiao-Hua, Ma; Jing-Jing, Ma; Cheng, Zhu

    2010-01-01

    The degradation of AlGaN/GaN high electron mobility transistors (HEMTs) has a close relationship with a model of traps in AlGaN barriers as a result of high electric field. We mainly discuss the impacts of strong electrical field on the AlGaN barrier thickness of AlGaN/GaN HEMTs. It is found that the device with a thin AlGaN barrier layer is more easily degraded. We study the degradation of four parameters, i.e. the gate series resistance R Gate , channel resistance R channel , gate current I G,off at V GS = −5 and V DS = 0.1 V, and drain current I D,max at V GS = 2 and V DS = 5 V. In addition, the degradation mechanisms of the device electrical parameters are also investigated in detail. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  19. Understanding the electric field control of the electronic and optical properties of strongly-coupled multi-layered quantum dot molecules.

    Science.gov (United States)

    Usman, Muhammad

    2015-10-21

    Strongly-coupled quantum dot molecules (QDMs) are widely employed in the design of a variety of optoelectronic, photovoltaic, and quantum information devices. An efficient and optimized performance of these devices demands engineering of the electronic and optical properties of the underlying QDMs. The application of electric fields offers a way to realise such a control over the QDM characteristics for a desired device operation. We performed multi-million-atom atomistic tight-binding calculations to study the influence of electric fields on the electron and hole wave function confinements and symmetries, the ground-state transition energies, the band-gap wavelengths, and the optical transition modes. Electrical fields parallel (Ep) and anti-parallel (Ea) to the growth direction were investigated to provide a comprehensive guide for understanding the electric field effects. The strain-induced asymmetry of the hybridized electron states is found to be weak and can be balanced by applying a small Ea electric field, of the order of 1 kV cm(-1). The strong interdot couplings completely break down at large electric fields, leading to single QD states confined at the opposite edges of the QDM. This mimics a transformation from a type-I band structure to a type-II band structure for the QDMs, which is a critical requirement for the design of intermediate-band solar cells (IBSCs). The analysis of the field-dependent ground-state transition energies reveals that the QDM can be operated both as a high dipole moment device by applying large electric fields and as a high polarizability device under the application of small electric field magnitudes. The quantum confined Stark effect (QCSE) red shifts the band-gap wavelength to 1.3 μm at the 15 kV cm(-1) electric field; however the reduced electron-hole wave function overlaps lead to a decrease in the interband optical transition strengths by roughly three orders of magnitude. The study of the polarisation-resolved optical

  20. The role of radial particle pinches in ELM suppression by resonant magnetic perturbations

    International Nuclear Information System (INIS)

    Stacey, W.M.; Evans, T.E.

    2011-01-01

    The force balance in the plasma edge in a matched pair of DIII-D (Luxon 2002 Nucl. Fusion 42 6149) tokamak discharges with and without resonant magnetic perturbations (RMPs) is evaluated in order to investigate the effects on particle transport of RMP applied for the purpose of suppressing edge-localized modes (ELMs). Experimental data are used to evaluate the radial and toroidal force balances, which may be written as a pinch-diffusion relation for the radial ion flux to facilitate investigation of transport effects. The radial electric field in the H-mode plasma had a sharp negative dip in the steep gradient region of the edge pedestal, associated with which was a large inward pinch velocity. The main effect of RMP was to make the edge electric field less negative or more positive, reducing this strong negative dip in the radial electric field (even reversing it from negative to positive over some regions), thereby reducing the strong inward particle pinch in the edge of an H-mode discharge, thus causing a reduction in edge density below the ELM threshold.

  1. Perturbation theory for the bloch electrons on strongly coupled chains in both uniform electric and magnetic fields

    International Nuclear Information System (INIS)

    Zhao, X.G.; Chen, S.G.

    1992-01-01

    In this paper, the energy spectrum and the wave functions for a tight-binding Bloch electron on coupled chains under the action of both uniform electric and magnetic fields are studied in detail. Exact results are obtained for the case when the coupling between chains is large by using the perturbation theory, from which it is found that the spectrum is that of two interspaced Stark ladders. The magnetic field dependence of the energy spectrum is also discussed

  2. More homogeneous wind conditions under strong climate change decrease the potential for inter-state balancing of electricity in Europe

    Science.gov (United States)

    Wohland, Jan; Reyers, Mark; Weber, Juliane; Witthaut, Dirk

    2017-11-01

    Limiting anthropogenic climate change requires the fast decarbonization of the electricity system. Renewable electricity generation is determined by the weather and is hence subject to climate change. We simulate the operation of a coarse-scale fully renewable European electricity system based on downscaled high-resolution climate data from EURO-CORDEX. Following a high-emission pathway (RCP8.5), we find a robust but modest increase (up to 7 %) of backup energy in Europe through the end of the 21st century. The absolute increase in the backup energy is almost independent of potential grid expansion, leading to the paradoxical effect that relative impacts of climate change increase in a highly interconnected European system. The increase is rooted in more homogeneous wind conditions over Europe resulting in intensified simultaneous generation shortfalls. Individual country contributions to European generation shortfall increase by up to 9 TWh yr-1, reflecting an increase of up to 4 %. Our results are strengthened by comparison with a large CMIP5 ensemble using an approach based on circulation weather types.

  3. Water surface deformation in strong electrical fields and its influence on electrical breakdown in a metal pin-water electrode system

    International Nuclear Information System (INIS)

    Bruggeman, Peter; Graham, Leigh; Groote, Joris de; Vierendeels, Jan; Leys, Christophe

    2007-01-01

    Electrical breakdown and water surface deformation in a metal pin-water electrode system with dc applied voltages is studied for small inter-electrode distances (2-12 mm). The radius of curvature of the metal pin is 0.5 cm to exclude corona before breakdown at these small inter-electrode spacings. Calculations of the water surface deformation as a function of the applied voltage and initial inter-electrode spacing are compared with measurements of the water elevation. For distances smaller than 7 mm the calculated stability limit of the water surface corresponds with the experimentally obtained breakdown voltage. It is proved with fast CCD images and calculations of the electrical field distribution that the water surface instability triggers the electrical breakdown in this case. The images show that at breakdown the water surface has a Taylor cone-like shape. At inter-electrode distance of 7 mm and larger the breakdown voltage is well below the water stability limit and the conductive channel at breakdown is formed between the pin electrode and the static water surface. Both cases are discussed and compared

  4. Radial MR images of the knee

    International Nuclear Information System (INIS)

    Hewes, R.C.; Miller, T.R.

    1988-01-01

    To profile optimally each portion of the meniscus, the authors use the multiangle, multisection feature of a General Electric SIGNA 1.5-T imager to produce radial images centered on each meniscus. A total of 12-15 sections are imaged at 10 0 -15 0 intervals of each meniscus, yielding perpendicular images of the entire meniscus, comparable with the arthrographic tangential views. The authors review their technique and demonstrate correlation cases between the radial gradient recalled acquisition in a steady state sequences, sagittal and coronal MR images, and arthrograms. Radial images should be a routine part of knee MR imaging

  5. Correlations Between Secondary Cosmic Ray Ratesand Strong Electric Fields at Lomnický štít

    Czech Academy of Sciences Publication Activity Database

    Kudela, Karel; Chum, Jaroslav; Kollárik, M.; Langer, R.; Strhárský, I.; Baše, Jiří

    2017-01-01

    Roč. 122, č. 20 (2017), s. 10700-10710 ISSN 2169-897X R&D Projects: GA ČR(CZ) GC15-07281J; GA MŠk EF15_003/0000481 Grant - others:AV ČR(CZ) BAS-17-04 Program:Bilaterální spolupráce Institutional support: RVO:68378289 ; RVO:61389005 Keywords : cosmic rays * thunderstorms * electric field Subject RIV: DG - Athmosphere Sciences, Meteorology; BL - Plasma and Gas Discharge Physics (UFA-U) OBOR OECD: Meteorology and atmospheric sciences; Fluids and plasma physics (including surface physics) (UFA-U) Impact factor: 3.454, year: 2016

  6. Electron drift velocity in SF{sub 6} in strong electric fields determined from rf breakdown curves

    Energy Technology Data Exchange (ETDEWEB)

    Lisovskiy, V; Yegorenkov, V [Department of Physics and Technology, Kharkov National University, Svobody sq.4, Kharkov 61077 (Ukraine); Booth, J-P [Laboratoire de Physique des Plasmas, Ecole Polytechnique, Palaiseau 91128 (France); Landry, K [Unaxis Displays Division France SAS, 5, Rue Leon Blum, Palaiseau 91120 (France); Douai, D [Physical Sciences Division, Institute for Magnetic Fusion Research, CEA Centre de Cadarache, F-13108 Saint Paul lez Durance Cedex (France); Cassagne, V, E-mail: lisovskiy@yahoo.co [Developpement Photovoltaique Couches Minces, Total, 2, place Jean Millier, La Defense 6, 92400 Courbevoie (France)

    2010-09-29

    This paper presents measurements of the electron drift velocity V{sub dr} in SF{sub 6} gas for high reduced electric fields (E/N = 330-5655 Td (1 Td = 10{sup -17} V cm{sup 2})). The drift velocities were obtained using the method of Lisovskiy and Yegorenkov (1998 J. Phys. D: Appl. Phys. 31 3349) based on the determination of the pressure and voltage of the turning points of rf capacitive discharge breakdown curves for a range of electrode spacings. The V{sub dr} values thus obtained were in good agreement with those calculated from the cross-sections of Phelps and Van Brunt (1988 J. Appl. Phys. 64 4269) using the BOLSIG code. The validity of the Lisovskiy-Yegorenkov method is discussed and we show that it is applicable over the entire E/N range where rf discharge ignition at breakdown occurs for rf frequencies of 13.56 MHz or above.

  7. Chiral symmetry in the strong color-electric field in terms of Nambu-Jona-Lasinio model

    International Nuclear Information System (INIS)

    Suganuma, Hideo

    1990-01-01

    We examine the behavior of chiral symmetry in an external gluon field using Nambu-Jona-Lasinio model, which is an effective theory of QCD. The Dyson equation for the dynamical quark mass in the presence of the external color-electric field is obtained. By solving it in the color flux tube inside mesons, chiral symmetry would be restored in the flux tube of mesons and this result supports Chiral Bag picture for mesons. Next we consider the flux tubes formed in the central region for ultra-relativistic heavy-ion collisions, and find the chiral restoration occurs there, so that the current quark mass seems to be suitable in calculating the q-q-bar pair creation rate by the Schwinger formula in the flux-tube picture. (author)

  8. Brain electric correlates of strong belief in paranormal phenomena: intracerebral EEG source and regional Omega complexity analyses.

    Science.gov (United States)

    Pizzagalli, D; Lehmann, D; Gianotti, L; Koenig, T; Tanaka, H; Wackermann, J; Brugger, P

    2000-12-22

    The neurocognitive processes underlying the formation and maintenance of paranormal beliefs are important for understanding schizotypal ideation. Behavioral studies indicated that both schizotypal and paranormal ideation are based on an overreliance on the right hemisphere, whose coarse rather than focussed semantic processing may favor the emergence of 'loose' and 'uncommon' associations. To elucidate the electrophysiological basis of these behavioral observations, 35-channel resting EEG was recorded in pre-screened female strong believers and disbelievers during resting baseline. EEG data were subjected to FFT-Dipole-Approximation analysis, a reference-free frequency-domain dipole source modeling, and Regional (hemispheric) Omega Complexity analysis, a linear approach estimating the complexity of the trajectories of momentary EEG map series in state space. Compared to disbelievers, believers showed: more right-located sources of the beta2 band (18.5-21 Hz, excitatory activity); reduced interhemispheric differences in Omega complexity values; higher scores on the Magical Ideation scale; more general negative affect; and more hypnagogic-like reveries after a 4-min eyes-closed resting period. Thus, subjects differing in their declared paranormal belief displayed different active, cerebral neural populations during resting, task-free conditions. As hypothesized, believers showed relatively higher right hemispheric activation and reduced hemispheric asymmetry of functional complexity. These markers may constitute the neurophysiological basis for paranormal and schizotypal ideation.

  9. Radial optimization of a BWR fuel cell using genetic algorithms

    International Nuclear Information System (INIS)

    Martin del Campo M, C.; Carmona H, R.; Oropeza C, I.P.

    2006-01-01

    The development of the application of the Genetic Algorithms (GA) to the optimization of the radial distribution of enrichment in a cell of fuel of a BWR (Boiling Water Reactor) is presented. The optimization process it was ties to the HELIOS simulator, which is a transport code of neutron simulation of fuel cells that has been validated for the calculation of nuclear banks for BWRs. With heterogeneous radial designs can improve the radial distribution of the power, for what the radial design of fuel has a strong influence in the global design of fuel recharges. The optimum radial distribution of fuel bars is looked for with different enrichments of U 235 and contents of consumable poison. For it is necessary to define the representation of the solution, the objective function and the implementation of the specific optimization process to the solution of the problem. The optimization process it was coded in 'C' language, it was automated the creation of the entrances to the simulator, the execution of the simulator and the extraction, in the exit of the simulator, of the parameters that intervene in the objective function. The objective function includes four parameters: average enrichment of the cell, average gadolinia concentration of the cell, peak factor of radial power and k-infinite multiplication factor. To be able to calculate the parameters that intervene in the objective function, the one evaluation process of GA was ties to the HELIOS code executed in a Compaq Alpha workstation. It was applied to the design of a fuel cell of 10 x 10 that it can be employee in the fuel assemble designs that are used at the moment in the Laguna Verde Nucleo electric Central. Its were considered 10 different fuel compositions which four contain gadolinia. Three heuristic rules that consist in prohibiting the placement of bars with gadolinia in the ends of the cell, to place the compositions with the smallest enrichment in the corners of the cell and to fix the placement of

  10. Evaluation of electrical resistivity anisotropy in geological mapping ...

    African Journals Online (AJOL)

    user

    Key words: Electrical resistivity anisotropy, radial vertical electrical sounding, anisotropy polygons. INTRODUCTION ... electrical resistivity survey in the geological interpretation ... resistivity and other electrical or electromagnetic based.

  11. Radial nerve dysfunction (image)

    Science.gov (United States)

    The radial nerve travels down the arm and supplies movement to the triceps muscle at the back of the upper arm. ... the wrist and hand. The usual causes of nerve dysfunction are direct trauma, prolonged pressure on the ...

  12. Some peculiarities of electro-optical effect in lead magno-niobate in strong alternative electric fields in the region of washing off phase transition

    International Nuclear Information System (INIS)

    Krajnik, N.N.; Trepakov, V.A.; Kamzina, L.S.; Sakharov, D.G.; Volik, B.A.; Pis'mennyj, V.A.; Skornyakova, K.P.

    1975-01-01

    An investigation was made of the transverse electrooptic effect in PbMgsub(1/3)Nbsub(2/3)O 3 subjected to alternating fields of 0-20 kV/cm intensity and 2.10-10 4 Hz frequency in the region of the broad ferroelectric phase tansition. The quadratic electrooptic coefficients (R 11 -R 12 ) exhibited relaxation-type maxima in the temperature dependences, whereas no such maxima were observed for the linear coefficients (r 33 -r 13 ) in the investigated temperature range: The latter coefficients rose monotonically when the temperature was lowered. It was concluded that the predominant despersion mechanism in strong fields was the inertia of the growth of ferroelectric domains and nuclei. The coefficients (M 11 -M 12 ), which were quadratic in respect of the polarization, increased with rising temperature and this was explained qualitatively by allowing for the contribution of orientation processes to the overall electric polarization and birefrigence. (author)

  13. Electricity

    CERN Document Server

    Basford, Leslie

    2013-01-01

    Electricity Made Simple covers the fundamental principles underlying every aspect of electricity. The book discusses current; resistance including its measurement, Kirchhoff's laws, and resistors; electroheat, electromagnetics and electrochemistry; and the motor and generator effects of electromagnetic forces. The text also describes alternating current, circuits and inductors, alternating current circuits, and a.c. generators and motors. Other methods of generating electromagnetic forces are also considered. The book is useful for electrical engineering students.

  14. Radial wedge flange clamp

    Science.gov (United States)

    Smith, Karl H.

    2002-01-01

    A radial wedge flange clamp comprising a pair of flanges each comprising a plurality of peripheral flat wedge facets having flat wedge surfaces and opposed and mating flat surfaces attached to or otherwise engaged with two elements to be joined and including a series of generally U-shaped wedge clamps each having flat wedge interior surfaces and engaging one pair of said peripheral flat wedge facets. Each of said generally U-shaped wedge clamps has in its opposing extremities apertures for the tangential insertion of bolts to apply uniform radial force to said wedge clamps when assembled about said wedge segments.

  15. Radial interchange motions of plasma filaments

    DEFF Research Database (Denmark)

    Garcia, O.E.; Bian, N.H.; Fundamenski, W.

    2006-01-01

    on a biperiodic domain perpendicular to the magnetic field. It is demonstrated that a blob-like plasma structure develops dipolar vorticity and electrostatic potential fields, resulting in rapid radial acceleration and formation of a steep front and a trailing wake. While the dynamical evolution strongly depends...

  16. Sirenomelia with radial dysplasia.

    Science.gov (United States)

    Kulkarni, M L; Abdul Manaf, K M; Prasannakumar, D G; Kulkarni, Preethi M

    2004-05-01

    Sirenomelia is a rare anomaly usually associated with other multiple malformations. In this communication the authors report a case of sirenomelia associated with multiple malformations, which include radial hypoplasia also. Though several theories have been proposed regarding the etiology of multiple malformation syndromes in the past, the recent theory of primary developmental defect during blastogenesis holds good in this case.

  17. Radially truncated galactic discs

    NARCIS (Netherlands)

    Grijs, R. de; Kregel, M.; Wesson, K H

    2000-01-01

    Abstract: We present the first results of a systematic analysis of radially truncatedexponential discs for four galaxies of a sample of disc-dominated edge-onspiral galaxies. Edge-on galaxies are very useful for the study of truncatedgalactic discs, since we can follow their light distributions out

  18. Theoretical study of structure of electric field in helical toroidal plasmas

    International Nuclear Information System (INIS)

    Toda, S.; Itoh, K.

    2001-06-01

    A set of transport equations is analyzed, including the bifurcation of the electric field. The structure of the electric field is studied by use of the theoretical model for the anomalous transport diffusivities. The steep gradient of the electric field is obtained at the electric domain. The suppression of the anomalous transport diffusivity is studied in the presence of the strong shear of the electric field. The hard transition with the multiple ambipolar solutions is examined in the structure of the radial electric field. The details of the structure of the electric domain interface are investigated. (author)

  19. Study of electric field pulsation in helical plasmas

    International Nuclear Information System (INIS)

    Toda, S; Itoh, K

    2011-01-01

    A model for the experimental results of the periodic oscillation of the electric field, so-called the electric field pulsation, observed in the Compact Helical Device (Fujisawa et al 1998 Phys. Rev. Lett. 81 2256) and the Large Helical Device (Shimizu et al 2010 Plasma Fusion Res. 5 S1015) is presented. A self-generated oscillation of the radial electric field is shown as the simulation result in helical plasmas. The reduction of the anomalous transport diffusivity in the core region is observed due to the strong shear of the radial electric field when the positive electric field is shown in the core region in the periodic oscillation of E r . Two different time scales are found in the self-generated oscillation, which are the transport time scale and the fast time scale at the transition of the radial electric field. This oscillation because of the hysteresis characteristic is attributed to the electric field pulsation observed in helical plasmas. The parameter region of the condition for the self-generated oscillation is derived. It is shown that the multiple solutions of the radial electric field for the ambipolar condition are necessary but not sufficient for obtaining the self-generated oscillation.

  20. Electric machine

    Science.gov (United States)

    El-Refaie, Ayman Mohamed Fawzi [Niskayuna, NY; Reddy, Patel Bhageerath [Madison, WI

    2012-07-17

    An interior permanent magnet electric machine is disclosed. The interior permanent magnet electric machine comprises a rotor comprising a plurality of radially placed magnets each having a proximal end and a distal end, wherein each magnet comprises a plurality of magnetic segments and at least one magnetic segment towards the distal end comprises a high resistivity magnetic material.

  1. Strong drifts effects on neoclassical transport

    International Nuclear Information System (INIS)

    Tessarotto, M.; Gregoratto, D.; White, R.B.

    1996-01-01

    It is well known that strong drifts play an important role in plasma equilibrium, stability and confinement A significant example concerns, in particular for tokamak plasmas, the case of strong toroidal differential rotation produced by E x B drift which is currently regarded as potentially important for its influence in equilibrium, stability and transport. In fact, theoretically, it has been found that shear flow can substantially affect the stability of microinstabilities as well modify substantially transport. Recent experimental observations of enhanced confinement and transport regimes in Tokamaks, show, however, evidence of the existence of strong drifts in the plasma core. These are produced not only by the radial electric field [which gives rise to the E x B drift], but also by density [N s ], temperature [T s ] and mass flow [V = ωRe var-phi , with e var-phi the toroidal unit vector, R the distance for the symmetry axis of the torus and ω being the toroidal angular rotation velocity] profiles which are suitably steep. This implies that, in a significant part of the plasma core, the relevant scale lengths of the gradients [of N s , T s , ω], i.e., respectively L N , L T and L ω can be as large as the radial scale length characterizing the banana orbits, L b . Interestingly enough, the transport estimates obtained appear close or even lower than the predictions based on the simplest neoclassical model. However, as is well known, the latter applies, in a strict sense only in the case of weak drifts and also ignoring even the contribution of shear flow related to strong E x B drift. Thus a fundamental problem appears the extension of neoclassical transport theory to include the effect of strong drifts in Tokamak confinement systems. The goal of this investigation is to develop a general formulation of neoclassical transport embodying such important feature

  2. Variable stator radial turbine

    Science.gov (United States)

    Rogo, C.; Hajek, T.; Chen, A. G.

    1984-01-01

    A radial turbine stage with a variable area nozzle was investigated. A high work capacity turbine design with a known high performance base was modified to accept a fixed vane stagger angle moveable sidewall nozzle. The nozzle area was varied by moving the forward and rearward sidewalls. Diffusing and accelerating rotor inlet ramps were evaluated in combinations with hub and shroud rotor exit rings. Performance of contoured sidewalls and the location of the sidewall split line with respect to the rotor inlet was compared to the baseline. Performance and rotor exit survey data are presented for 31 different geometries. Detail survey data at the nozzle exit are given in contour plot format for five configurations. A data base is provided for a variable geometry concept that is a viable alternative to the more common pivoted vane variable geometry radial turbine.

  3. Estimation of Radial Runout

    OpenAIRE

    Nilsson, Martin

    2007-01-01

    The demands for ride comfort quality in today's long haulage trucks are constantly growing. A part of the ride comfort problems are represented by internal vibrations caused by rotating mechanical parts. This thesis work focus on the vibrations generated from radial runout on the wheels. These long haulage trucks travel long distances on smooth highways, with a constant speed of 90 km/h resulting in a 7 Hz oscillation. This frequency creates vibrations in the cab, which can be found annoying....

  4. Radial Fuzzy Systems

    Czech Academy of Sciences Publication Activity Database

    Coufal, David

    2017-01-01

    Roč. 319, 15 July (2017), s. 1-27 ISSN 0165-0114 R&D Projects: GA MŠk(CZ) LD13002 Institutional support: RVO:67985807 Keywords : fuzzy systems * radial functions * coherence Subject RIV: BA - General Mathematics OBOR OECD: Computer sciences, information science, bioinformathics (hardware development to be 2.2, social aspect to be 5.8) Impact factor: 2.718, year: 2016

  5. Perceived radial translation during centrifugation

    NARCIS (Netherlands)

    Bos, J.E.; Correia Grácio, B.J.

    2015-01-01

    BACKGROUND: Linear acceleration generally gives rise to translation perception. Centripetal acceleration during centrifugation, however, has never been reported giving rise to a radial, inward translation perception. OBJECTIVE: To study whether centrifugation can induce a radial translation

  6. Electricity

    International Nuclear Information System (INIS)

    Tombs, F.

    1983-01-01

    The subject is discussed, with particular reference to the electricity industry in the United Kingdom, under the headings; importance and scope of the industry's work; future fuel supplies (estimated indigenous fossil fuels reserves); outlook for UK energy supplies; problems of future generating capacity and fuel mix (energy policy; construction programme; economics and pricing; contribution of nuclear power - thermal and fast reactors; problems of conversion of oil-burning to coal-burning plant). (U.K.)

  7. Radial reflection diffraction tomography

    Science.gov (United States)

    Lehman, Sean K.

    2012-12-18

    A wave-based tomographic imaging method and apparatus based upon one or more rotating radially outward oriented transmitting and receiving elements have been developed for non-destructive evaluation. At successive angular locations at a fixed radius, a predetermined transmitting element can launch a primary field and one or more predetermined receiving elements can collect the backscattered field in a "pitch/catch" operation. A Hilbert space inverse wave (HSIW) algorithm can construct images of the received scattered energy waves using operating modes chosen for a particular application. Applications include, improved intravascular imaging, bore hole tomography, and non-destructive evaluation (NDE) of parts having existing access holes.

  8. Radial transport of poloidal momentum in ASDEX Upgrade in L-mode and H-mode

    DEFF Research Database (Denmark)

    Schrittwieser, R.; Mehlmann, F.; Naulin, Volker

    2012-01-01

    A reciprocating probe was used for localized measurements of the radial transport of poloidal momentum in the scrape-off layer (SOL) of ASDEX Upgrade (AUG). The probe measured poloidal and radial electric field components and density. We concentrate on three components of the momentum transport: ......: Reynolds stress, convective momentum flux and triple product of the fluctuating components of density, radial and poloidal electric field. For the evaluation we draw mainly on the probability density functions (PDFs)....

  9. Introducing radiality constraints in capacitated location-routing problems

    Directory of Open Access Journals (Sweden)

    Eliana Mirledy Toro Ocampo

    2017-03-01

    Full Text Available In this paper, we introduce a unified mathematical formulation for the Capacitated Vehicle Routing Problem (CVRP and for the Capacitated Location Routing Problem (CLRP, adopting radiality constraints in order to guarantee valid routes and eliminate subtours. This idea is inspired by formulations already employed in electric power distribution networks, which requires a radial topology in its operation. The results show that the proposed formulation greatly improves the convergence of the solver.

  10. Fuel radial design using Path Relinking

    International Nuclear Information System (INIS)

    Campos S, Y.

    2007-01-01

    The present work shows the obtained results when implementing the combinatory optimization technique well-known as Path Re linking (Re-linkage of Trajectories), to the problem of the radial design of nuclear fuel assemblies, for boiling water reactors (BWR Boiling Water Reactor by its initials in English), this type of reactors is those that are used in the Laguna Verde Nucleo electric Central, Veracruz. As in any other electric power generation plant of that make use of some fuel to produce heat and that it needs each certain time (from 12 to 14 months) to make a supply of the same one, because this it wears away or it burns, in the nucleolectric plants to this activity is denominated fuel reload. In this reload different activities intervene, among those which its highlight the radial and axial designs of fuel assemblies, the patterns of control rods and the multi cycles study, each one of these stages with their own complexity. This work was limited to study in independent form the radial design, without considering the other activities. These phases are basic for the fuel reload design and of reactor operation strategies. (Author)

  11. Radial optimization of a BWR fuel cell using genetic algorithms; Optimizacion radial de una celda de combustible BWR usando algoritmos geneticos

    Energy Technology Data Exchange (ETDEWEB)

    Martin del Campo M, C.; Carmona H, R.; Oropeza C, I.P. [UNAM, Paseo Cuauhnahuac 8532, 62550 Jiutepec, Morelos (Mexico)]. e-mail: cmcm@fi-b.unam.mx

    2006-07-01

    The development of the application of the Genetic Algorithms (GA) to the optimization of the radial distribution of enrichment in a cell of fuel of a BWR (Boiling Water Reactor) is presented. The optimization process it was ties to the HELIOS simulator, which is a transport code of neutron simulation of fuel cells that has been validated for the calculation of nuclear banks for BWRs. With heterogeneous radial designs can improve the radial distribution of the power, for what the radial design of fuel has a strong influence in the global design of fuel recharges. The optimum radial distribution of fuel bars is looked for with different enrichments of U{sup 235} and contents of consumable poison. For it is necessary to define the representation of the solution, the objective function and the implementation of the specific optimization process to the solution of the problem. The optimization process it was coded in 'C' language, it was automated the creation of the entrances to the simulator, the execution of the simulator and the extraction, in the exit of the simulator, of the parameters that intervene in the objective function. The objective function includes four parameters: average enrichment of the cell, average gadolinia concentration of the cell, peak factor of radial power and k-infinite multiplication factor. To be able to calculate the parameters that intervene in the objective function, the one evaluation process of GA was ties to the HELIOS code executed in a Compaq Alpha workstation. It was applied to the design of a fuel cell of 10 x 10 that it can be employee in the fuel assemble designs that are used at the moment in the Laguna Verde Nucleo electric Central. Its were considered 10 different fuel compositions which four contain gadolinia. Three heuristic rules that consist in prohibiting the placement of bars with gadolinia in the ends of the cell, to place the compositions with the smallest enrichment in the corners of the cell and to fix

  12. Radial semiconductor drift chambers

    International Nuclear Information System (INIS)

    Rawlings, K.J.

    1987-01-01

    The conditions under which the energy resolution of a radial semiconductor drift chamber based detector system becomes dominated by the step noise from the detector dark current have been investigated. To minimise the drift chamber dark current attention should be paid to carrier generation at Si/SiO 2 interfaces. This consideration conflicts with the desire to reduce the signal risetime: a higher drift field for shorter signal pulses requires a larger area of SiO 2 . Calculations for the single shaping and pseudo Gaussian passive filters indicate that for the same degree of signal risetime sensitivity in a system dominated by the step noise from the detector dark current, the pseudo Gaussian filter gives only a 3% improvement in signal/noise and 12% improvement in rate capability compared with the single shaper performance. (orig.)

  13. ISR Radial Field Magnet

    CERN Multimedia

    1983-01-01

    There were 37 (normal) + 3 (special) Radial Field magnets in the ISR to adjust vertically the closed orbit. Gap heights and strengths were 200 mm and .12 Tm in the normal magnets, 220 mm and .18 Tm in the special ones. The core length was 430 mm in both types. Due to their small length as compared to the gap heights the end fringe field errors were very important and had to be compensated by suitably shaping the poles. In order to save on cables, as these magnets were located very far from their power supplies, the coils of the normal type magnets were formed by many turns of solid cpper conductor with some interleaved layers of hollow conductor directly cooled by circulating water

  14. The ARCS radial collimator

    International Nuclear Information System (INIS)

    Stone, M.B.; Abernathy, D.L.; Niedziela, J.L.; Overbay, M.A.

    2015-01-01

    We have designed, installed, and commissioned a scattered beam radial collimator for use at the ARCS Wide Angular Range Chopper Spectrometer at the Spallation Neutron Source. The collimator has been designed to work effectively for thermal and epithermal neutrons and with a range of sample environments. Other design considerations include the accommodation of working within a high vacuum environment and having the ability to quickly install and remove the collimator from the scattered beam. The collimator is composed of collimating blades (or septa). The septa are 12 micron thick Kapton foils coated on each side with 39 microns of enriched boron carbide ( 10 B 4 C with 10 B > 96%) in an ultra-high vacuum compatible binder. The collimator blades represent an additional 22 m 2 of surface area. In the article we present collimator's design and performance and methodologies for its effective use

  15. Antiproton compression and radial measurements

    CERN Document Server

    Andresen, G B; Bowe, P D; Bray, C C; Butler, E; Cesar, C L; Chapman, S; Charlton, M; Fajans, J; Fujiwara, M C; Funakoshi, R; Gill, D R; Hangst, J S; Hardy, W N; Hayano, R S; Hayden, M E; Humphries, A J; Hydomako, R; Jenkins, M J; Jorgensen, L V; Kurchaninov, L; Lambo, R; Madsen, N; Nolan, P; Olchanski, K; Olin, A; Page R D; Povilus, A; Pusa, P; Robicheaux, F; Sarid, E; Seif El Nasr, S; Silveira, D M; Storey, J W; Thompson, R I; Van der Werf, D P; Wurtele, J S; Yamazaki, Y

    2008-01-01

    Control of the radial profile of trapped antiproton clouds is critical to trapping antihydrogen. We report detailed measurements of the radial manipulation of antiproton clouds, including areal density compressions by factors as large as ten, achieved by manipulating spatially overlapped electron plasmas. We show detailed measurements of the near-axis antiproton radial profile, and its relation to that of the electron plasma. We also measure the outer radial profile by ejecting antiprotons to the trap wall using an octupole magnet.

  16. Radial expansion and multifragmentation

    International Nuclear Information System (INIS)

    Angelique, J.C.; Bizard, G.; Bougault, R.; Brou, R.; Buta, A.; Colin, J.; Cussol, D.; Durand, D.; Kerambrun, A.; Le Brun, C.; Lecolley, J.F.; Lopez, O.; Louvel, M.; Meslin, C.; Nakagawa, T.; Patry, J.P.; Peter, J.; Popescu, R.; Regimbart, R.; Steckmeyer, J.C.; Tamain, B.; Vient, E.; Yuasa-Nakagawa, K.; Wieloch, A.

    1998-01-01

    The light systems 36 Ar + 27 Al and 64 Zn + nat Ti were measured at several bombarding energies between ∼ 35 and 95 MeV/nucleon. It was found that the predominant part of the cross section is due to binary collisions. In this paper the focus is placed on the properties of the quasi-projectile nuclei. In the central collisions the excitation energies of the quasi-projectile reach values exceeding largely 10 MeV/nucleon. The slope of the high energy part of the distribution can give only an upper limit of the apparent temperature (the average temperature along the decay chain). The highly excited quasi-projectile may get rapidly fragmented rather than sequentially. The heavy fragments are excited and can emit light particles (n, p, d, t, 3 He, α,...) what perturbs additionally the spectrum of these particles. Concerning the expansion energy, one can determine the average kinetic energies of the product (in the quasi-projectile-framework) and compare with simulation values. To fit the experimental data an additional radial expansion energy is to be considered. The average expansion energy depends slightly on the impact parameter but it increases with E * / A, ranging from 0.4 to 1,2 MeV/nucleon for an excitation energy increasing from 7 to 10.5 MeV/nucleon. This collective radial energy seems to be independent of the fragment mass, what is possibly valid for the case of larger quasi-projectile masses. The origin of the expansion is to be determined. It may be due to a compression in the interaction zone at the initial stage of the collision, which propagates in the quasi-projectile and quasi-target, or else, may be due, simply, to the increase of thermal energy leading to a rapid fragment emission. The sequential de-excitation calculation overestimates light particle emission and consequently heavy residues, particularly, at higher excitation energies. This disagreement indicates that a sequential process can not account for the di-excitation of very hot nuclei

  17. THE NONLINEAR OHM'S LAW: PLASMA HEATING BY STRONG ELECTRIC FIELDS AND ITS EFFECTS ON THE IONIZATION BALANCE IN PROTOPLANETARY DISKS

    Energy Technology Data Exchange (ETDEWEB)

    Okuzumi, Satoshi [Department of Earth and Planetary Sciences, Tokyo Institute of Technology, Meguro-ku, Tokyo 152-8551 (Japan); Inutsuka, Shu-ichiro, E-mail: okuzumi@geo.titech.ac.jp [Department of Physics, Nagoya University, Nagoya, Aichi 464-8602 (Japan)

    2015-02-10

    The ionization state of the gas plays a key role in the magnetohydrodynamics (MHD) of protoplanetary disks. However, the ionization state can depend on the gas dynamics, because electric fields induced by MHD turbulence can heat up plasmas and thereby affect the ionization balance. To study this nonlinear feedback, we construct an ionization model that includes plasma heating by electric fields and impact ionization by heated electrons, as well as charging of dust grains. We show that when plasma sticking onto grains is the dominant recombination process, the electron abundance in the gas decreases with increasing electric field strength. This is a natural consequence of electron-grain collisions whose frequency increases with the electron's random velocity. The decreasing electron abundance may lead to a self-regulation of MHD turbulence. In some cases, not only the electron abundance but also the electric current decreases with increasing field strength in a certain field range. The resulting N-shaped current-field relation violates the fundamental assumption of the non-relativistic MHD that the electric field is uniquely determined by the current density. At even higher field strengths, impact ionization causes an abrupt increase of the electric current as expected by previous studies. We find that this discharge current is multi-valued (i.e., the current-field relation is S-shaped) under some circumstances, and that the intermediate branch is unstable. The N/S-shaped current-field relations may yield hysteresis in the evolution of MHD turbulence in some parts of protoplanetary disks.

  18. Condition of damping of anomalous radial transport, determined by ordered convective electron dynamics

    International Nuclear Information System (INIS)

    Maslov, V.I.; Barchuk, S.V.; Lapshin, V.I.; Volkov, E.D.; Melentsov, Yu.V.

    2006-01-01

    It is shown, that at development of instability due to a radial gradient of density in the crossed electric and magnetic fields in nuclear fusion installations ordering convective cells can be excited. It provides anomalous particle transport. The spatial structures of these convective cells have been constructed. The radial dimensions of these convective cells depend on their amplitudes and on a radial gradient of density. The convective-diffusion equation for radial dynamics of the electrons has been derived. At the certain value of the universal controlling parameter, the convective cell excitation and the anomalous radial transport are suppressed. (author)

  19. Radial gas turbine design

    Energy Technology Data Exchange (ETDEWEB)

    Krausche, S.; Ohlsson, Johan

    1998-04-01

    The objective of this work was to develop a program dealing with design point calculations of radial turbine machinery, including both compressor and turbine, with as few input data as possible. Some simple stress calculations and turbine metal blade temperatures were also included. This program was then implanted in a German thermodynamics program, Gasturb, a program calculating design and off-design performance of gas turbines. The calculations proceed with a lot of assumptions, necessary to finish the task, concerning pressure losses, velocity distribution, blockage, etc., and have been correlated with empirical data from VAT. Most of these values could have been input data, but to prevent the user of the program from drowning in input values, they are set as default values in the program code. The output data consist of geometry, Mach numbers, predicted component efficiency etc., and a number of graphical plots of geometry and velocity triangles. For the cases examined, the error in predicted efficiency level was within {+-} 1-2% points, and quite satisfactory errors in geometrical and thermodynamic conditions were obtained Examination paper. 18 refs, 36 figs

  20. Radial flow heat exchanger

    Science.gov (United States)

    Valenzuela, Javier

    2001-01-01

    A radial flow heat exchanger (20) having a plurality of first passages (24) for transporting a first fluid (25) and a plurality of second passages (26) for transporting a second fluid (27). The first and second passages are arranged in stacked, alternating relationship, are separated from one another by relatively thin plates (30) and (32), and surround a central axis (22). The thickness of the first and second passages are selected so that the first and second fluids, respectively, are transported with laminar flow through the passages. To enhance thermal energy transfer between first and second passages, the latter are arranged so each first passage is in thermal communication with an associated second passage along substantially its entire length, and vice versa with respect to the second passages. The heat exchangers may be stacked to achieve a modular heat exchange assembly (300). Certain heat exchangers in the assembly may be designed slightly differently than other heat exchangers to address changes in fluid properties during transport through the heat exchanger, so as to enhance overall thermal effectiveness of the assembly.

  1. Strong Schottky barrier reduction at Au-catalyst/GaAs-nanowire interfaces by electric dipole formation and Fermi-level unpinning.

    Science.gov (United States)

    Suyatin, Dmitry B; Jain, Vishal; Nebol'sin, Valery A; Trägårdh, Johanna; Messing, Maria E; Wagner, Jakob B; Persson, Olof; Timm, Rainer; Mikkelsen, Anders; Maximov, Ivan; Samuelson, Lars; Pettersson, Håkan

    2014-01-01

    Nanoscale contacts between metals and semiconductors are critical for further downscaling of electronic and optoelectronic devices. However, realizing nanocontacts poses significant challenges since conventional approaches to achieve ohmic contacts through Schottky barrier suppression are often inadequate. Here we report the realization and characterization of low n-type Schottky barriers (~0.35 eV) formed at epitaxial contacts between Au-In alloy catalytic particles and GaAs-nanowires. In comparison to previous studies, our detailed characterization, employing selective electrical contacts defined by high-precision electron beam lithography, reveals the barrier to occur directly and solely at the abrupt interface between the catalyst and nanowire. We attribute this lowest-to-date-reported Schottky barrier to a reduced density of pinning states (~10(17) m(-2)) and the formation of an electric dipole layer at the epitaxial contacts. The insight into the physical mechanisms behind the observed low-energy Schottky barrier may guide future efforts to engineer abrupt nanoscale electrical contacts with tailored electrical properties.

  2. Stability of radial swirl flows

    International Nuclear Information System (INIS)

    Dou, H S; Khoo, B C

    2012-01-01

    The energy gradient theory is used to examine the stability of radial swirl flows. It is found that the flow of free vortex is always stable, while the introduction of a radial flow will induce the flow to be unstable. It is also shown that the pure radial flow is stable. Thus, there is a flow angle between the pure circumferential flow and the pure radial flow at which the flow is most unstable. It is demonstrated that the magnitude of this flow angle is related to the Re number based on the radial flow rate, and it is near the pure circumferential flow. The result obtained in this study is useful for the design of vaneless diffusers of centrifugal compressors and pumps as well as other industrial devices.

  3. Channeling of protons through radial deformed carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Borka Jovanović, V., E-mail: vborka@vinca.rs [Atomic Physics Laboratory (040), Vinča Institute of Nuclear Sciences, University of Belgrade, P.O. Box 522, 11001 Belgrade (Serbia); Borka, D. [Atomic Physics Laboratory (040), Vinča Institute of Nuclear Sciences, University of Belgrade, P.O. Box 522, 11001 Belgrade (Serbia); Galijaš, S.M.D. [Faculty of Physics, University of Belgrade, P.O. Box 368, 11001 Belgrade (Serbia)

    2017-05-18

    Highlights: • For the first time we presented theoretically obtained distributions of channeled protons with radially deformed SWNT. • Our findings indicate that influence of the radial deformation is very strong and it should not be omitted in simulations. • We show that the spatial and angular distributions depend strongly of level of radial deformation of nanotube. • Our obtained results can be compared with measured distributions to reveal the presence of various types of defects in SWNT. - Abstract: In this paper we have presented a theoretical investigation of the channeling of 1 GeV protons with the radial deformed (10, 0) single-wall carbon nanotubes (SWNTs). We have calculated channeling potential within the deformed nanotubes. For the first time we presented theoretically obtained spatial and angular distributions of channeled protons with radially deformed SWNT. We used a Monte Carlo (MC) simulation technique. We show that the spatial and angular distributions depend strongly of level of radial deformation of nanotube. These results may be useful for nanotube characterization and production and guiding of nanosized ion beams.

  4. <strong>Mini-project>

    DEFF Research Database (Denmark)

    Katajainen, Jyrki

    2008-01-01

    In this project the goal is to develop the safe * family of containers for the CPH STL. The containers to be developed should be safer and more reliable than any of the existing implementations. A special focus should be put on strong exception safety since none of the existing prototypes available...

  5. Strong interactions

    International Nuclear Information System (INIS)

    Froissart, Marcel

    1976-01-01

    Strong interactions are introduced by their more obvious aspect: nuclear forces. In hadron family, the nucleon octet, OMEGA - decuplet, and quark triply are successively considered. Pion wave having been put at the origin of nuclear forces, low energy phenomena are described, the force being explained as an exchange of structure corresponding to a Regge trajectory in a variable rotating state instead of the exchange of a well defined particle. At high energies the concepts of pomeron, parton and stratons are introduced, pionization and fragmentation are briefly differentiated [fr

  6. Fuel radial design using Path Relinking; Diseno radial de combustible usando Path Relinking

    Energy Technology Data Exchange (ETDEWEB)

    Campos S, Y. [ININ, 52750 La Marquesa, Estado de Mexico (Mexico)

    2007-07-01

    The present work shows the obtained results when implementing the combinatory optimization technique well-known as Path Re linking (Re-linkage of Trajectories), to the problem of the radial design of nuclear fuel assemblies, for boiling water reactors (BWR Boiling Water Reactor by its initials in English), this type of reactors is those that are used in the Laguna Verde Nucleo electric Central, Veracruz. As in any other electric power generation plant of that make use of some fuel to produce heat and that it needs each certain time (from 12 to 14 months) to make a supply of the same one, because this it wears away or it burns, in the nucleolectric plants to this activity is denominated fuel reload. In this reload different activities intervene, among those which its highlight the radial and axial designs of fuel assemblies, the patterns of control rods and the multi cycles study, each one of these stages with their own complexity. This work was limited to study in independent form the radial design, without considering the other activities. These phases are basic for the fuel reload design and of reactor operation strategies. (Author)

  7. Radial retinotomy in the macula.

    Science.gov (United States)

    Bovino, J A; Marcus, D F

    1984-01-01

    Radial retinotomy is an operative procedure usually performed in the peripheral or equatorial retina. To facilitate retinal attachment, the authors used intraocular scissors to perform radial retinotomy in the macula of two patients during vitrectomy surgery. In the first patient, a retinal detachment complicated by periretinal proliferation and macula hole formation was successfully reoperated with the aid of three radial cuts in the retina at the edges of the macular hole. In the second patient, an intraoperative retinal tear in the macula during diabetic vitrectomy was also successfully repaired with the aid of radial retinotomy. In both patients, retinotomy in the macula was required because epiretinal membranes, which could not be easily delaminated, were hindering retinal reattachment.

  8. Detonation in supersonic radial outflow

    KAUST Repository

    Kasimov, Aslan R.; Korneev, Svyatoslav

    2014-01-01

    We report on the structure and dynamics of gaseous detonation stabilized in a supersonic flow emanating radially from a central source. The steady-state solutions are computed and their range of existence is investigated. Two-dimensional simulations

  9. Dedicated radial ventriculography pigtail catheter

    Energy Technology Data Exchange (ETDEWEB)

    Vidovich, Mladen I., E-mail: miv@uic.edu

    2013-05-15

    A new dedicated cardiac ventriculography catheter was specifically designed for radial and upper arm arterial access approach. Two catheter configurations have been developed to facilitate retrograde crossing of the aortic valve and to conform to various subclavian, ascending aortic and left ventricular anatomies. The “short” dedicated radial ventriculography catheter is suited for horizontal ascending aortas, obese body habitus, short stature and small ventricular cavities. The “long” dedicated radial ventriculography catheter is suited for vertical ascending aortas, thin body habitus, tall stature and larger ventricular cavities. This new design allows for improved performance, faster and simpler insertion in the left ventricle which can reduce procedure time, radiation exposure and propensity for radial artery spasm due to excessive catheter manipulation. Two different catheter configurations allow for optimal catheter selection in a broad range of patient anatomies. The catheter is exceptionally stable during contrast power injection and provides equivalent cavity opacification to traditional femoral ventriculography catheter designs.

  10. A novel energy transfer inducing strong enhancement of electric dipole transition in Na3Mo12PO40:xEu3+ phosphors

    Science.gov (United States)

    Long, Jinqiao; Wang, Tianman; Luo, Zhirong; Gao, Yong; Song, Baoling; Liang, Jing; Liao, Sen; Huang, Yingheng; Zhang, Huaxin

    2017-08-01

    A series of Na3Mo12PO40:xEu3+ phosphors have been successfully synthesized by a solid-state method, and characterized by powder x-ray diffraction (PXRD). The PXRD results confirm that the samples have crystal phases of Na3Mo12PO40. For PL spectra of Na3Mo12PO40:2.0Eu3+ excited by 394 and 465 nm, R (R is the peak area ratio of 5D0  →  7F2 to 5D0  →  7F1) is only 1.46 with an excitation of 394 nm, but increases to 3.03 with an excitation of 465 nm. Furthermore, a new enhancement of electric dipole transition is observed. Emission spectrum (PL) intensity at 617 nm excited by 465 nm is 1.95 times as high as the excitation spectrum (PLE) intensity at 465 nm. Thus, cooperative energy transfers from the magnetic dipole (MD) Eu3+ center to the electric dipole (ED) Eu3+ center when excited by 465 nm is demonstrated for the new fluorescent behavior.

  11. Electric quadrupole moments and strong interaction effects in pionic atoms of 165Ho, 175Lu, 176Lu, 179Hf and 181Ta

    International Nuclear Information System (INIS)

    Olaniyi, B.; Shor, A.; Cheng, S.C.; Dugan, G.; Wu, C.S.

    1981-05-01

    The effective quadrupole moments Q sub(eff) of the nuclei of 165 Ho, 175 Lu, 176 Lu, 179 Hf and 181 Ta were accurately measured by detecting the pionic atom 5g-4f x-rays of the elements. The spectroscopic quadrupole moments, Q sub(spec), were obtained by correcting Q sub(eff) for nuclear finite size effect, distortion of the pion wave function by the pion-nucleus strong interaction, and contribution to the energy level splittings by the strong interaction. The intrinsic quadrupole moments, Q 0 , were obtained by projecting Q sub(spec) into the frame of reference fixed on the nucleus. The shift, epsilon 0 , and broadening, GAMMA 0 , of the 4f energy level due to the strong interactions between the pion and the nucleons for all the elements were also measured. Theoretical values of epsilon 0 and GAMMA 0 were calculated and compared to the experimental values. The measured values of Q 0 were compared with the existing results in muonic and pionic atoms. The measured values of epsilon 0 and GAMMA 0 were also compared with existing values. (auth)

  12. Kinetic transport properties of a bumpy torus with finite radial ambipolar field

    International Nuclear Information System (INIS)

    Spong, D.A.; Harris, E.G.; Hedrick, C.L.

    1978-04-01

    Bumpy torus neoclassical transport coefficients have been calculted including finite values of the radial ambipolar field. These are obtained by solving a bounce-averaged drift kinetic equation in a local approximation for perturbations in the distribution function (away from a stationary Maxwellian) caused by toroidicity and radial gradients in plasma density, temperature, and potential. Particle and energy fluxes along with the associated transport coefficients are then calculated by taking appropriate moments of the distribution function. Particle orbits are treated by breaking them up into a vertical drift component (due to toroidicity) and a theta precessional drift (as a result of Vector E x Vector B and drifts due to the bumpy toroidal field). The kinetic equation has been solved using both a functional expansion method and finite difference techniques [Alternating-Direction-Implicit (ADI)]. The resulting transport coefficients exhibit a strong dependence on the ambipolar electric field and plasma collisionality. In the large electric field limit, our results are in close agreement with the earlier work of Kovrizhnykh

  13. Radial lean direct injection burner

    Science.gov (United States)

    Khan, Abdul Rafey; Kraemer, Gilbert Otto; Stevenson, Christian Xavier

    2012-09-04

    A burner for use in a gas turbine engine includes a burner tube having an inlet end and an outlet end; a plurality of air passages extending axially in the burner tube configured to convey air flows from the inlet end to the outlet end; a plurality of fuel passages extending axially along the burner tube and spaced around the plurality of air passage configured to convey fuel from the inlet end to the outlet end; and a radial air swirler provided at the outlet end configured to direct the air flows radially toward the outlet end and impart swirl to the air flows. The radial air swirler includes a plurality of vanes to direct and swirl the air flows and an end plate. The end plate includes a plurality of fuel injection holes to inject the fuel radially into the swirling air flows. A method of mixing air and fuel in a burner of a gas turbine is also provided. The burner includes a burner tube including an inlet end, an outlet end, a plurality of axial air passages, and a plurality of axial fuel passages. The method includes introducing an air flow into the air passages at the inlet end; introducing a fuel into fuel passages; swirling the air flow at the outlet end; and radially injecting the fuel into the swirling air flow.

  14. Double unification of particles with fields and electricity with gravity in non-empty space of continuous complex energies

    Directory of Open Access Journals (Sweden)

    Bulyzhenkov Igor E.

    2016-01-01

    Full Text Available Non-empty space reading of Maxwell equations as local energy identities explains why a Coulomb field is carried rigidly by electrons in experiments. The analytical solution of the Poisson equation defines the sharp radial shape of charged elementary densities which are proportional to continuous densities of electric self-energy. Both Coulomb field and radial charge densities are free from energy divergences. Non-empty space of electrically charged mass-energy can be described by complex analytical densities resulting in real values for volume mass integrals and in imaginary values for volume charge integrals. Imaginary electric charges in the Newton gravitational law comply with real Coulomb forces. Unification of forces through complex charges rids them of radiation self-acceleration. Strong gravitational fields repeal probe bodies that might explainthe accelerated expansion of the dense Metagalaxy. Outward and inward spherical waves form the standing wave process within the radial carrier of complex energy.

  15. Detonation in supersonic radial outflow

    KAUST Repository

    Kasimov, Aslan R.

    2014-11-07

    We report on the structure and dynamics of gaseous detonation stabilized in a supersonic flow emanating radially from a central source. The steady-state solutions are computed and their range of existence is investigated. Two-dimensional simulations are carried out in order to explore the stability of the steady-state solutions. It is found that both collapsing and expanding two-dimensional cellular detonations exist. The latter can be stabilized by putting several rigid obstacles in the flow downstream of the steady-state sonic locus. The problem of initiation of standing detonation stabilized in the radial flow is also investigated numerically. © 2014 Cambridge University Press.

  16. Numerical simulation of liquid-metal-flows in radial-toroidal-radial bends

    International Nuclear Information System (INIS)

    Molokov, S.; Buehler, L.

    1993-09-01

    Magnetohydrodynamic flows in a U-bend and right-angle bend are considered with reference to the radial-toroidal-radial concept of a self-cooled liquid-metal blanket. The ducts composing bends have rectangular cross-section. The applied magnetic field is aligned with the toroidal duct and perpendicular to the radial ones. At high Hartmann number the flow region is divided into cores and boundary layers of different types. The magnetohydrodynamic equations are reduced to a system of partial differential equations governing wall electric potentials and the core pressure. The system is solved numerically by two different methods. The first method is iterative with iteration between wall potential and the core pressure. The second method is a general one for the solution of the core flow equations in curvilinear coordinates generated by channel geometry and magnetic field orientation. Results obtained are in good agreement. They show, that the 3D-pressure drop of MHD flows in a U-bend is not a critical issue for blanket applications. (orig./HP) [de

  17. RADIALLY MAGNETIZED PROTOPLANETARY DISK: VERTICAL PROFILE

    International Nuclear Information System (INIS)

    Russo, Matthew; Thompson, Christopher

    2015-01-01

    This paper studies the response of a thin accretion disk to an external radial magnetic field. Our focus is on protoplanetary disks (PPDs), which are exposed during their later evolution to an intense, magnetized wind from the central star. A radial magnetic field is mixed into a thin surface layer, wound up by the disk shear, and pushed downward by a combination of turbulent mixing and ambipolar and ohmic drift. The toroidal field reaches much greater strengths than the seed vertical field that is usually invoked in PPD models, even becoming superthermal. Linear stability analysis indicates that the disk experiences the magnetorotational instability (MRI) at a higher magnetization than a vertically magnetized disk when both the effects of ambipolar and Hall drift are taken into account. Steady vertical profiles of density and magnetic field are obtained at several radii between 0.06 and 1 AU in response to a wind magnetic field B r ∼ (10 −4 –10 −2 )(r/ AU) −2 G. Careful attention is given to the radial and vertical ionization structure resulting from irradiation by stellar X-rays. The disk is more strongly magnetized closer to the star, where it can support a higher rate of mass transfer. As a result, the inner ∼1 AU of a PPD is found to evolve toward lower surface density. Mass transfer rates around 10 −8 M ⊙ yr −1 are obtained under conservative assumptions about the MRI-generated stress. The evolution of the disk and the implications for planet migration are investigated in the accompanying paper

  18. RADIALLY MAGNETIZED PROTOPLANETARY DISK: VERTICAL PROFILE

    Energy Technology Data Exchange (ETDEWEB)

    Russo, Matthew [Department of Physics, University of Toronto, 60 St. George St., Toronto, ON M5S 1A7 (Canada); Thompson, Christopher [Canadian Institute for Theoretical Astrophysics, 60 St. George St., Toronto, ON M5S 3H8 (Canada)

    2015-11-10

    This paper studies the response of a thin accretion disk to an external radial magnetic field. Our focus is on protoplanetary disks (PPDs), which are exposed during their later evolution to an intense, magnetized wind from the central star. A radial magnetic field is mixed into a thin surface layer, wound up by the disk shear, and pushed downward by a combination of turbulent mixing and ambipolar and ohmic drift. The toroidal field reaches much greater strengths than the seed vertical field that is usually invoked in PPD models, even becoming superthermal. Linear stability analysis indicates that the disk experiences the magnetorotational instability (MRI) at a higher magnetization than a vertically magnetized disk when both the effects of ambipolar and Hall drift are taken into account. Steady vertical profiles of density and magnetic field are obtained at several radii between 0.06 and 1 AU in response to a wind magnetic field B{sub r} ∼ (10{sup −4}–10{sup −2})(r/ AU){sup −2} G. Careful attention is given to the radial and vertical ionization structure resulting from irradiation by stellar X-rays. The disk is more strongly magnetized closer to the star, where it can support a higher rate of mass transfer. As a result, the inner ∼1 AU of a PPD is found to evolve toward lower surface density. Mass transfer rates around 10{sup −8} M{sub ⊙} yr{sup −1} are obtained under conservative assumptions about the MRI-generated stress. The evolution of the disk and the implications for planet migration are investigated in the accompanying paper.

  19. Propagation of strong electromagnetic beams in inhomogeneous plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Ferrari, A; Massaglia, S [Consiglio Nazionale delle Ricerche, Turin (Italy). Lab. di Cosmo-Geofisica; Turin Univ. (Italy). Ist. di Fisica Generale)

    1980-09-01

    We study some simple aspects of nonlinear propagation of relativistically strong electromagnetic beams in inhomogeneous plasmas, especially in connection with effects of beam self-trapping in extended extragalactic radio sources. The two effects of (i) long scale longitudinal and radial inhomogeneities inherent to the plasma and (ii) radial inhomogeneities produced by the ponderomotive force of the beam itself are investigated.

  20. Radial head dislocation during proximal radial shaft osteotomy.

    Science.gov (United States)

    Hazel, Antony; Bindra, Randy R

    2014-03-01

    The following case report describes a 48-year-old female patient with a longstanding both-bone forearm malunion, who underwent osteotomies of both the radius and ulna to improve symptoms of pain and lack of rotation at the wrist. The osteotomies were templated preoperatively. During surgery, after performing the planned radial shaft osteotomy, the authors recognized that the radial head was subluxated. The osteotomy was then revised from an opening wedge to a closing wedge with improvement of alignment and rotation. The case report discusses the details of the operation, as well as ways in which to avoid similar shortcomings in the future. Copyright © 2014 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.

  1. Tight focusing of radially polarized circular Airy vortex beams

    Science.gov (United States)

    Chen, Musheng; Huang, Sujuan; Shao, Wei

    2017-11-01

    Tight focusing properties of radially polarized circular Airy vortex beams (CAVB) are studied numerically. The light field expressions for the focused fields are derived based on vectorial Debye theory. We also study the relationship between focal profiles, such as light intensity distribution, radius of focal spot and focal length, and the parameters of CAVB. Numerical results demonstrate that we can generate a radially polarized CAVB with super-long focal length, super-strong longitudinal intensity or subwavelength focused spot at the focal plane by properly choosing the parameters of incident light and high numerical aperture (NA) lens. These results have potential applications for optical trapping, optical storage and particle acceleration.

  2. Plasma rotation under a driven radial current in a tokamak

    International Nuclear Information System (INIS)

    Chang, C.S.

    1999-01-01

    The neoclassical behaviour of plasma rotation under a driven radial electrical current is studied in a tokamak geometry. An ambipolar radial electric field develops instantly in such a way that the driven current is balanced by a return current j p in the plasma. The j p x B torque pushes the plasma into a new rotation state both toroidally and poloidally. An anomalous toroidal viscosity is needed to avoid an extreme toroidal rotation speed. It is shown that the poloidal rotation relaxes to a new equilibrium speed, which is in general smaller than the E x B poloidal speed, and that the timescale for the relaxation of poloidal rotation is the same as that of toroidal rotation generation, which is usually much longer than the ion-ion collision time. (author)

  3. RADIAL STABILITY IN STRATIFIED STARS

    International Nuclear Information System (INIS)

    Pereira, Jonas P.; Rueda, Jorge A.

    2015-01-01

    We formulate within a generalized distributional approach the treatment of the stability against radial perturbations for both neutral and charged stratified stars in Newtonian and Einstein's gravity. We obtain from this approach the boundary conditions connecting any two phases within a star and underline its relevance for realistic models of compact stars with phase transitions, owing to the modification of the star's set of eigenmodes with respect to the continuous case

  4. The radial velocity variations in IC 418

    International Nuclear Information System (INIS)

    Mendez, R.H.; Verga, A.D.

    1981-01-01

    The observations presented are part of a search for spectral and radial velocity variations among central stars of planetary nebulae and include the following new data: 1) Weak, previously undetected C III emissions are visible at 4056, 4186, 4516, 5270 and 5826 A. The famous unidentified emissions at 4485 and 4503 A were also found. 2) The He I absorptions at 4471 and 5875 A are blue-shifted relative to the nebular emissions. The same happens with Hsub(delta) and Hsub(γ), although in this case the shift can be at least partly attributed to blends with the strong He II absorptions, which are estimated to contribute about one half of the equivalent width at Hsub(delta) and Hsub(γ). 3) O III 5592 and C IV 5801, 5811 are also found in absorption. (Auth.)

  5. Velocidades radiales en Collinder 121

    Science.gov (United States)

    Arnal, M.; Morrell, N.

    Se han llevado a cabo observaciones espectroscópicas de unas treinta estrellas que son posibles miembros del cúmulo abierto Collinder 121. Las mismas fueron realizadas con el telescopio de 2.15m del Complejo Astronómico El Leoncito (CASLEO). El análisis de las velocidades radiales derivadas del material obtenido, confirma la realidad de Collinder 121, al menos desde el punto de vista cinemático. La velocidad radial baricentral (LSR) del cúmulo es de +17 ± 3 km.s-1. Esta velocidad coincide, dentro de los errores, con la velocidad radial (LSR) de la nebulosa anillo S308, la cual es de ~20 ± 10 km.s-1. Como S308 se encuentra físicamente asociada a la estrella Wolf-Rayet HD~50896, es muy probable que esta última sea un miembro de Collinder 121. Desde un punto de vista cinemático, la supergigante roja HD~50877 (K3Iab) también pertenecería a Collinder 121. Basándonos en la pertenencia de HD~50896 a Collinder 121, y en la interacción encontrada entre el viento de esta estrella y el medio interestelar circundante a la misma, se estima para este cúmulo una distancia del orden de 1 kpc.

  6. Electron–Cyclotron Laser Using Free-Electron Two-Quantum Stark Radiation in a Strong Uniform Axial Magnetic Field and an Alternating Axial Electric Field in a Voltage-Supplied Pill-Box Cavity

    International Nuclear Information System (INIS)

    Kim, S. H.

    2016-01-01

    We consider the radiation from the beam electrons traveling in a strong uniform axial magnetic field and an axial alternating electric field of wavelength λ_w generated by a voltage-supplied pill-box cavity. The beam electrons emit genuine laser radiation that propagates only in the axial direction through free-electron two-quantum Stark radiation. We find that laser radiation takes place only at the expense of the axial kinetic energy when λ_w ≪ c/(ω_c/γ), where ω_c/γ is the relativistic electron–cyclotron frequency. We formulate the laser power based on quantum-wiggler electrodynamics, and envision a laser of length 10 m with estimated power 0.1 GW/(kA) in the 10"−"4 cm wavelength range. (paper)

  7. The effect of radial migration on galactic disks

    International Nuclear Information System (INIS)

    Vera-Ciro, Carlos; D'Onghia, Elena; Navarro, Julio; Abadi, Mario

    2014-01-01

    We study the radial migration of stars driven by recurring multi-arm spiral features in an exponential disk embedded in a dark matter halo. The spiral perturbations redistribute angular momentum within the disk and lead to substantial radial displacements of individual stars, in a manner that largely preserves the circularity of their orbits and that results, after 5 Gyr (∼40 full rotations at the disk scale length), in little radial heating and no appreciable changes to the vertical or radial structure of the disk. Our results clarify a number of issues related to the spatial distribution and kinematics of migrators. In particular, we find that migrators are a heavily biased subset of stars with preferentially low vertical velocity dispersions. This 'provenance bias' for migrators is not surprising in hindsight, for stars with small vertical excursions spend more time near the disk plane, and thus respond more readily to non-axisymmetric perturbations. We also find that the vertical velocity dispersion of outward migrators always decreases, whereas the opposite holds for inward migrators. To first order, newly arrived migrators simply replace stars that have migrated off to other radii, thus inheriting the vertical bias of the latter. Extreme migrators might therefore be recognized, if present, by the unexpectedly small amplitude of their vertical excursions. Our results show that migration, understood as changes in angular momentum that preserve circularity, can strongly affect the thin disk, but cast doubts on models that envision the Galactic thick disk as a relic of radial migration.

  8. Quantum electrodynamics of strong fields

    International Nuclear Information System (INIS)

    Greiner, W.

    1983-01-01

    Quantum Electrodynamics of Strong Fields provides a broad survey of the theoretical and experimental work accomplished, presenting papers by a group of international researchers who have made significant contributions to this developing area. Exploring the quantum theory of strong fields, the volume focuses on the phase transition to a charged vacuum in strong electric fields. The contributors also discuss such related topics as QED at short distances, precision tests of QED, nonperturbative QCD and confinement, pion condensation, and strong gravitational fields In addition, the volume features a historical paper on the roots of quantum field theory in the history of quantum physics by noted researcher Friedrich Hund

  9. Electric field bifurcation and transition in the core plasma of CHS

    International Nuclear Information System (INIS)

    Fujisawa, A.; Iguchi, H.; Sanuki, H.; Itoh, K.; Okamura, S.; Matsuoka, K.; Hamada, Y.; Itoh, S.-I.

    1997-01-01

    In the CHS heliotron/torsatron, dynamic phenomena associated with transitions in radial electric field were observed during combined ECH+NBI heated plasmas. The observations with high temporal resolution confirmed a nonlinear relation between radial electric field and radial current to cause these phenomena associated with electric field bifurcation. (author)

  10. Research of long pulse high current diode radial insulation

    International Nuclear Information System (INIS)

    Tan Jie; Chang Anbi; Hu Kesong; Liu Qingxiang; Ma Qiaosheng; Liu Zhong

    2002-01-01

    A radial insulation structure which is used in long pulse high current diode is introduced. The theory of vacuum flashover and the idea of design are briefly introduced. In the research, cone-shaped insulator was used. The geometry structure parameters were optimized by simulating the static electrical field distribution. Experiment was done on a pulse power source with 200 ns pulse width. The maximum voltage 750 kV was obtained, and the average stand-off electrical field of insulator is about 50 kV/cm

  11. Crystal Growth of High-Quality Protein Crystals under the Presence of an Alternant Electric Field in Pulse-Wave Mode, and a Strong Magnetic Field with Radio Frequency Pulses Characterized by X-ray Diffraction

    Directory of Open Access Journals (Sweden)

    Adela Rodríguez-Romero

    2017-06-01

    Full Text Available The first part of this research was devoted to investigating the effect of alternate current (AC using four different types of wave modes (pulse-wave at 2 Hz on the crystal growth of lysozyme in solution. The best results, in terms of size and crystal quality, were obtained when protein crystals were grown under the influence of electric fields in a very specific wave mode (“breathing” wave, giving the highest resolution up to 1.34 Å in X-ray diffraction analysis compared with controls and with those crystals grown in gel. In the second part, we evaluated the effect of a strong magnetic field of 16.5 Tesla combined with radiofrequency pulses of 0.43 μs on the crystal growth in gels of tetragonal hen egg white (HEW lysozyme. The lysozyme crystals grown, both in solution applying breathing-wave and in gel under the influence of this strong magnetic field with pulses of radio frequencies, produced the larger-in-size crystals and the highest resolution structures. Data processing and refinement statistics are very good in terms of the resolution, mosaicity and Wilson B factor obtained for each crystal. Besides, electron density maps show well-defined and distinctly separated atoms at several selected tryptophan residues for the crystal grown using the “breathing wave pulses”.

  12. The Electric Car Challenge.

    Science.gov (United States)

    Diehl, Brian E.

    1997-01-01

    Describes the Electric Car Challenge during which students applied methods of construction to build lightweight, strong vehicles that were powered by electricity. The activity required problem solving, sheet metal work, electricity, design, and construction skills. (JOW)

  13. Finite-difference time-domain (FDTD) analysis on the interaction between a metal block and a radially polarized focused beam.

    Science.gov (United States)

    Kitamura, Kyoko; Sakai, Kyosuke; Noda, Susumu

    2011-07-18

    Radially polarized focused beams have attracted a great deal of attention because of their unique properties characterized by the longitudinal field. Although this longitudinal field is strongly confined to the beam axis, the energy flow, i.e., the Poynting vector, has null intensity on the axis. Hence, the interaction of the focused beam and matter has thus far been unclear. We analyzed the interactions between the focused beam and a subwavelength metal block placed at the center of the focus using three-dimensional finite-difference time-domain (FDTD) calculation. We found that most of the Poynting energy propagates through to the far-field, and that a strong enhancement of the electric field appeared on the metal surface. This enhancement is attributed to the constructive interference of the symmetric electric field and the coupling to the surface plasmon mode.

  14. Strongly capacitively coupled double quantum dots in GaAs-AlGaAs heterostructures. Preparation and electrical transport; Kapazitativ stark gekoppelte Doppelquantenpunkte in GaAs-AlGaAs-Heterostrukturen. Herstellung und elektrischer Transport

    Energy Technology Data Exchange (ETDEWEB)

    Huebel, A.

    2007-11-22

    In this work, a double quantum dot system is studied whose two dots are electrically insulated from one another and contacted independently with two leads. The geometry is optimized to maximize the capacitive interaction between the dots. The samples are characterized by electrical transport measurements in a dilution refrigerator. It is then studied at different tunnel couplings how the capacitive interaction influences the electrical transport in equilibrium. Under certain conditions correlated tunnel processes can be observed. A simple model is derived that serves to understand these processes. The double quantum dot system is defined in lateral arrangement by reactive ion etching of a two-dimensional electron system located only 50 nm below the surface of a GaAs-AlGaAs heterostructure. The samples are characterized in a dilution refrigerator at 25 mK near the common pinch-off point of all four tunnel barriers. A measurement of the differential equilibrium conductances of both quantum dots as a function of two gate voltages yields a honeycomb-like charge stability diagram. The most important sample characteristic is the ratio between the interaction capacitance and the total capacitance of a single quantum dot. For the optimized sample, this ratio turns out to be larger than one third near the common pinch-off point, with a single-dot charging energy of up to 800 {mu}eV. At more positive gate voltages, the capacitances between the quantum dots and their leads increase more and more, thereby diminishing the charging energy. It is shown for the optimized sample that all capacitance coefficients except the dot-lead capacitances are constant to within considerable accuracy over several Coulomb blockade oscillations. In order to measure correlated electrical transport in equilibrium, special parameter regions are examined in which the charges of both quantum dots cannot fluctuate independently of each other. An analytical formula is derived that describes the

  15. Transition from steady to periodic liquid-metal magnetohydrodynamic flow in a sliding electrical contact

    Science.gov (United States)

    Talmage, Gita; Walker, John S.; Brown, Samuel H.; Sondergaard, Neal A.

    1993-09-01

    In homopolar motors and generators, large dc electric currents pass through the sliding electrical contacts between rotating copper disks (rotors) and static copper surfaces shrouding the rotor tips (stators). A liquid metal in the small radial gap between the rotor tip and concentric stator surface can provide a low-resistance, low-drag electrical contact. Since there is a strong magnetic field in the region of the electrical contacts, there are large electromagnetic body forces on the liquid metal. The primary, azimuthal motion consists of simple Couette flow, plus an electromagnetically driven flow with large extremes of the azimuthal velocity near the rotor corners. The secondary flow involves the radial and axial velocity components, is driven by the centrifugal force associated with the primary flow, and is opposed by the electromagnetic body force, so that the circulation varies inversely as the square of the magnetic-field strength. Three flow regimes are identified as the angular velocity Ω of the rotor is increased. For small Ω, the primary flow is decoupled from the secondary flow. As Ω increases, the secondary flow begins to convect the azimuthal-velocity peaks radially outward, which in turn changes the centrifugal force driving the secondary flow. At some critical value of Ω, the flow becomes periodic through the coupling of the primary and secondary flows. The azimuthal-velocity peaks begin to move radially in and out with an accompanying oscillation in the secondary-flow strength.

  16. Exceptional circles of radial potentials

    International Nuclear Information System (INIS)

    Music, M; Perry, P; Siltanen, S

    2013-01-01

    A nonlinear scattering transform is studied for the two-dimensional Schrödinger equation at zero energy with a radial potential. Explicit examples are presented, both theoretically and computationally, of potentials with nontrivial singularities in the scattering transform. The singularities arise from non-uniqueness of the complex geometric optics solutions that define the scattering transform. The values of the complex spectral parameter at which the singularities appear are called exceptional points. The singularity formation is closely related to the fact that potentials of conductivity type are ‘critical’ in the sense of Murata. (paper)

  17. Optimal Operation of Radial Distribution Systems Using Extended Dynamic Programming

    DEFF Research Database (Denmark)

    Lopez, Juan Camilo; Vergara, Pedro P.; Lyra, Christiano

    2018-01-01

    An extended dynamic programming (EDP) approach is developed to optimize the ac steady-state operation of radial electrical distribution systems (EDS). Based on the optimality principle of the recursive Hamilton-Jacobi-Bellman equations, the proposed EDP approach determines the optimal operation o...... approach is illustrated using real-scale systems and comparisons with commercial programming solvers. Finally, generalizations to consider other EDS operation problems are also discussed.......An extended dynamic programming (EDP) approach is developed to optimize the ac steady-state operation of radial electrical distribution systems (EDS). Based on the optimality principle of the recursive Hamilton-Jacobi-Bellman equations, the proposed EDP approach determines the optimal operation...... of the EDS by setting the values of the controllable variables at each time period. A suitable definition for the stages of the problem makes it possible to represent the optimal ac power flow of radial EDS as a dynamic programming problem, wherein the 'curse of dimensionality' is a minor concern, since...

  18. Radial smoothing and closed orbit

    International Nuclear Information System (INIS)

    Burnod, L.; Cornacchia, M.; Wilson, E.

    1983-11-01

    A complete simulation leading to a description of one of the error curves must involve four phases: (1) random drawing of the six set-up points within a normal population having a standard deviation of 1.3 mm; (b) random drawing of the six vertices of the curve in the sextant mode within a normal population having a standard deviation of 1.2 mm. These vertices are to be set with respect to the axis of the error lunes, while this axis has as its origins the positions defined by the preceding drawing; (c) mathematical definition of six parabolic curves and their junctions. These latter may be curves with very slight curvatures, or segments of a straight line passing through the set-up point and having lengths no longer than one LSS. Thus one gets a mean curve for the absolute errors; (d) plotting of the actually observed radial positions with respect to the mean curve (results of smoothing)

  19. Waves on radial film flows

    Science.gov (United States)

    Cholemari, Murali R.; Arakeri, Jaywant H.

    2005-08-01

    We study the stability of surface waves on the radial film flow created by a vertical cylindrical water jet striking a horizontal plate. In such flows, surface waves have been found to be unstable and can cause transition to turbulence. This surface-wave-induced transition is different from the well-known Tollmien-Schlichting wave-induced transition. The present study aims at understanding the instability and the transition process. We do a temporal stability analysis by assuming the flow to be locally two-dimensional but including spatial variations to first order in the basic flow. The waves are found to be dispersive, mostly unstable, and faster than the mean flow. Spatial variation is the major destabilizing factor. Experiments are done to test the results of the linear stability analysis and to document the wave breakup and transition. Comparison between theory and experiments is fairly good and indicates the adequacy of the model.

  20. Radial flow gas dynamic laser

    International Nuclear Information System (INIS)

    Damm, F.C.

    1975-01-01

    The unique gas dynamic laser provides outward radial supersonic flow from a toroidal shaped stacked array of a plurality of nozzles, through a diffuser having ring shaped and/or linear shaped vanes, and through a cavity which is cylindrical and concentric with the stacked array, with the resultant laser beam passing through the housing parallel to the central axis of the diffuser which is coincident with the axis of the gas dynamic laser. Therefore, greater beam extraction flexibility is attainable, because of fewer flow shock disturbances, as compared to the conventional unidirectional flow gas dynamic laser in which unidirectional supersonic flow sweeps through a rectangular cavity and is exhausted through a two-dimensional diffuser. (auth)

  1. A strong nuclear sector

    International Nuclear Information System (INIS)

    Toivola, A.

    2000-01-01

    Following the deregulation of the Nordic electricity market, imported electricity has accounted for an increasing share of Finland's electricity supply. Imports accounted for 14% of total electricity consumption in 1999. Increasing imports and the continuing growth of electricity consumption are undermining the traditional self-sufficiency of the country's electricity supply. The open electricity market has also seen uneconomical coal-fired units taken out of service, which has made them unavailable as reserve capacity. Overall, this has meant a decline in the security of the country's electricity supply

  2. Ulnar nerve entrapment complicating radial head excision

    Directory of Open Access Journals (Sweden)

    Kevin Parfait Bienvenu Bouhelo-Pam

    Full Text Available Introduction: Several mechanisms are involved in ischemia or mechanical compression of ulnar nerve at the elbow. Presentation of case: We hereby present the case of a road accident victim, who received a radial head excision for an isolated fracture of the radial head and complicated by onset of cubital tunnel syndrome. This outcome could be the consequence of an iatrogenic valgus of the elbow due to excision of the radial head. Hitherto the surgical treatment of choice it is gradually been abandoned due to development of radial head implant arthroplasty. However, this management option is still being performed in some rural centers with low resources. Discussion: The radial head plays an important role in the stability of the elbow and his iatrogenic deformity can be complicated by cubital tunnel syndrome. Conclusion: An ulnar nerve release was performed with favorable outcome. Keywords: Cubital tunnel syndrome, Peripheral nerve palsy, Radial head excision, Elbow valgus

  3. Radial Transport and Meridional Circulation in Accretion Disks

    Energy Technology Data Exchange (ETDEWEB)

    Philippov, Alexander A. [Department of Astrophysical Sciences, Princeton University, Ivy Lane, Princeton, NJ 08540 (United States); Rafikov, Roman R., E-mail: sashaph@princeton.edu [Institute for Advanced Study, Einstein Drive, Princeton, NJ 08540 (United States)

    2017-03-10

    Radial transport of particles, elements and fluid driven by internal stresses in three-dimensional (3D) astrophysical accretion disks is an important phenomenon, potentially relevant for the outward dust transport in protoplanetary disks, origin of the refractory particles in comets, isotopic equilibration in the Earth–Moon system, etc. To gain better insight into these processes, we explore the dependence of meridional circulation in 3D disks with shear viscosity on their thermal stratification, and demonstrate a strong effect of the latter on the radial flow. Previous locally isothermal studies have normally found a pattern of the radial outflow near the midplane, switching to inflow higher up. Here we show, both analytically and numerically, that a flow that is inward at all altitudes is possible in disks with entropy and temperature steeply increasing with height. Such thermodynamic conditions may be typical in the optically thin, viscously heated accretion disks. Disks in which these conditions do not hold should feature radial outflow near the midplane, as long as their internal stress is provided by the shear viscosity. Our results can also be used for designing hydrodynamical disk simulations with a prescribed pattern of the meridional circulation.

  4. Stirling Engine With Radial Flow Heat Exchangers

    Science.gov (United States)

    Vitale, N.; Yarr, George

    1993-01-01

    Conflict between thermodynamical and structural requirements resolved. In Stirling engine of new cylindrical configuration, regenerator and acceptor and rejector heat exchangers channel flow of working gas in radial direction. Isotherms in regenerator ideally concentric cylinders, and gradient of temperature across regenerator radial rather than axial. Acceptor and rejector heat exchangers located radially inward and outward of regenerator, respectively. Enables substantial increase in power of engine without corresponding increase in diameter of pressure vessel.

  5. Electric Motor-Generator for a Hybrid Electric Vehicle

    OpenAIRE

    Odvářka, Erik; Mebarki, Abdeslam; Gerada, David; Brown, Neil; Ondrůšek, Čestmír

    2009-01-01

    Several topologies of electrical machines can be used to meet requirements for application in a hybrid electric vehicle. This paper describes process of an electric motor-generator selection, considering electromagnetic, thermal and basic control design. The requested electrical machine must develop 45 kW in continuous operation at 1300 rpm with field weakening capability up to 2500 rpm. Both radial and axial flux topologies are considered as potential candidates. A family of axial flux machi...

  6. Charging dynamics and strong localization of a two-dimensional electron cloud

    International Nuclear Information System (INIS)

    Dianoux, R; Smilde, H J H; Marchi, F; Buffet, N; Mur, P; Comin, F; Chevrier, J

    2007-01-01

    The dynamics of charge injection in silicon nanocrystals embedded in a silicon dioxide matrix is studied using electrostatic force microscopy. We show that the presence of silicon nanocrystals with a density of 10 11 cm -2 is essential for strong localization of charges, and results in exceptional charge retention properties compared to nanocrystal-free SiO 2 samples. In both systems, a logarithmic dependence of the diameter of the charged area on the injection time is experimentally observed on a timescale between 0.1 and 10 s (voltage≤10 V). A field-emission injection, limited by Coulomb blockade and a lateral charge spreading due to a repulsive radial electric field are used to model the sample charging. Once the tip is retracted, the electron cloud is strongly confined in the nanocrystals and remains static

  7. Optical transitions in semiconductor nanospherical core/shell/shell heterostructure in the presence of radial electrostatic field

    Energy Technology Data Exchange (ETDEWEB)

    Baghdasaryan, D.A. [Russian-Armenian University, H. Emin 123, 0051 Yerevan (Armenia); Hayrapetyan, D.B., E-mail: dhayrap82@gmail.com [Russian-Armenian University, H. Emin 123, 0051 Yerevan (Armenia); Yerevan State University, A. Manoogian 1, 0025 Yerevan (Armenia); Harutyunyan, V.A. [Russian-Armenian University, H. Emin 123, 0051 Yerevan (Armenia)

    2017-04-01

    The electronic states and optical properties of spherical nanolayer in the presence of the electrostatic radial field in the strong size quantization regime have been considered. Both analytical and numerical methods have been applied to the problem of one-electron states in the system. According to the intensity of the external electrostatic field, three regimes have been distinguished: week, intermediate and strong. Perturbative approach have been applied to the case of week, WKB to the case of intermediate and variation approach to the case of strong field intensities. The analytical dependencies of the one electron energy and wave function on the electric field value and geometrical parameters of the nanolayer have been achieved. The comparison of the results obtained by the analytical method with the results of the numerical method have been made. The interband and intraband optical transitions caused by incident optical light polarized in z direction have been considered in this system. The selection rules for this transitions have been obtained. The dependence of the absorption coefficient on the energy of incident light for both cases of interband and intraband transitions for every regime of the electrostatic field value have been received. - Highlights: • The electron energy analytical dependencies on the electric field value have been achieved. • The selection rules for transitions between levels with different quantum numbers are revealed. • The interband and intraband absorption coefficients have been studied.

  8. Radial head button holing: a cause of irreducible anterior radial head dislocation

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Su-Mi; Chai, Jee Won; You, Ja Yeon; Park, Jina [Seoul National University Seoul Metropolitan Government Boramae Medical Center, Department of Radiology, Seoul (Korea, Republic of); Bae, Kee Jeong [Seoul National University Seoul Metropolitan Government Boramae Medical Center, Department of Orthopedic Surgery, Seoul (Korea, Republic of)

    2016-10-15

    ''Buttonholing'' of the radial head through the anterior joint capsule is a known cause of irreducible anterior radial head dislocation associated with Monteggia injuries in pediatric patients. To the best of our knowledge, no report has described an injury consisting of buttonholing of the radial head through the annular ligament and a simultaneous radial head fracture in an adolescent. In the present case, the radiographic findings were a radial head fracture with anterior dislocation and lack of the anterior fat pad sign. Magnetic resonance imaging (MRI) clearly demonstrated anterior dislocation of the fractured radial head through the torn annular ligament. The anterior joint capsule and proximal portion of the annular ligament were interposed between the radial head and capitellum, preventing closed reduction of the radial head. Familiarity with this condition and imaging findings will aid clinicians to make a proper diagnosis and fast decision to perform an open reduction. (orig.)

  9. Modeling Marine Electromagnetic Survey with Radial Basis Function Networks

    Directory of Open Access Journals (Sweden)

    Agus Arif

    2014-11-01

    Full Text Available A marine electromagnetic survey is an engineering endeavour to discover the location and dimension of a hydrocarbon layer under an ocean floor. In this kind of survey, an array of electric and magnetic receivers are located on the sea floor and record the scattered, refracted and reflected electromagnetic wave, which has been transmitted by an electric dipole antenna towed by a vessel. The data recorded in receivers must be processed and further analysed to estimate the hydrocarbon location and dimension. To conduct those analyses successfuly, a radial basis function (RBF network could be employed to become a forward model of the input-output relationship of the data from a marine electromagnetic survey. This type of neural networks is working based on distances between its inputs and predetermined centres of some basis functions. A previous research had been conducted to model the same marine electromagnetic survey using another type of neural networks, which is a multi layer perceptron (MLP network. By comparing their validation and training performances (mean-squared errors and correlation coefficients, it is concluded that, in this case, the MLP network is comparatively better than the RBF network[1].[1] This manuscript is an extended version of our previous paper, entitled Radial Basis Function Networks for Modeling Marine Electromagnetic Survey, which had been presented on 2011 International Conference on Electrical Engineering and Informatics, 17-19 July 2011, Bandung, Indonesia.

  10. Photoelectric Radial Velocities, Paper XIX Additional Spectroscopic ...

    Indian Academy of Sciences (India)

    ian velocity curve that does justice to the measurements, but it cannot be expected to have much predictive power. Key words. Stars: late-type—stars: radial velocities—spectroscopic binaries—orbits. 0. Preamble. The 'Redman K stars' are a lot of seventh-magnitude K stars whose radial velocities were first observed by ...

  11. Radial velocities of RR Lyrae stars

    International Nuclear Information System (INIS)

    Hawley, S.L.; Barnes, T.G. III

    1985-01-01

    283 spectra of 57 RR Lyrae stars have been obtained using the 2.1-m telescope at McDonald Observatory. Radial velocities were determined using a software cross-correlation technique. New mean radial velocities were determined for 46 of the stars. 11 references

  12. Concepts of radial and angular kinetic energies

    DEFF Research Database (Denmark)

    Dahl, Jens Peder; Schleich, W.P.

    2002-01-01

    We consider a general central-field system in D dimensions and show that the division of the kinetic energy into radial and angular parts proceeds differently in the wave-function picture and the Weyl-Wigner phase-space picture, Thus, the radial and angular kinetic energies are different quantities...

  13. RADIO POLARIMETRY SIGNATURES OF STRONG MAGNETIC TURBULENCE IN SUPERNOVA REMNANTS

    International Nuclear Information System (INIS)

    Stroman, Wendy; Pohl, Martin

    2009-01-01

    We discuss the emission and transport of polarized radio-band synchrotron radiation near the forward shocks of young shell-type supernova remnants, for which X-ray data indicate a strong amplification of turbulent magnetic field. Modeling the magnetic turbulence through the superposition of waves, we calculate the degree of polarization and the magnetic polarization direction which is at 90 deg. to the conventional electric polarization direction. We find that isotropic strong turbulence will produce weakly polarized radio emission even in the absence of internal Faraday rotation. If anisotropy is imposed on the magnetic-field structure, the degree of polarization can be significantly increased, provided internal Faraday rotation is inefficient. Both for shock compression and a mixture with a homogeneous field, the increase in polarization degree goes along with a fairly precise alignment of the magnetic-polarization angle with the direction of the dominant magnetic-field component, implying tangential magnetic polarization at the rims in the case of shock compression. We compare our model with high-resolution radio polarimetry data of Tycho's remnant. Using the absence of internal Faraday rotation we find a soft limit for the amplitude of magnetic turbulence, δB ∼ 0 . An alternative viable scenario involves anisotropic turbulence with stronger amplitudes in the radial direction, as was observed in recent Magnetohydrodynamics simulations of shocks propagating through a medium with significant density fluctuations.

  14. Acoustic resonances in two-dimensional radial sonic crystal shells

    Energy Technology Data Exchange (ETDEWEB)

    Torrent, Daniel; Sanchez-Dehesa, Jose, E-mail: jsdehesa@upvnet.upv.e [Wave Phenomena Group, Departamento de Ingenieria Electronica, Universidad Politecnica de Valencia, C/Camino de Vera s.n., E-46022 Valencia (Spain)

    2010-07-15

    Radial sonic crystals (RSC) are fluidlike structures infinitely periodic along the radial direction that verify the Bloch theorem and are possible only if certain specially designed acoustic metamaterials with mass density anisotropy can be engineered (see Torrent and Sanchez-Dehesa 2009 Phys. Rev. Lett. 103 064301). A comprehensive analysis of two-dimensional (2D) RSC shells is reported here. A given shell is in fact a circular slab with a central cavity. These finite crystal structures contain Fabry-Perot-like resonances and modes strongly localized at the central cavity. Semi-analytical expressions are developed to obtain the quality factors of the different resonances, their symmetry features and their excitation properties. The results reported here are completely general and can be extended to equivalent 3D spherical shells and to their photonic counterparts.

  15. A radial velocity survey of extremely hydrogen-deficient stars

    International Nuclear Information System (INIS)

    Jeffery, C.S.; Kiel Univ.; Drilling, J.S.; Heber, U.

    1987-01-01

    A radial velocity survey of hot extremely hydrogen-deficient stars has been carried out in order to search for possible binaries. The survey found three stars to have large velocity variations. Of these, two are known hydrogen-deficient binaries and one, HDE 320156 (= LSS 4300), is a suspected binary. HDE 320156 (= LSS 4300) is therefore confirmed to be a single-lined spectroscopic hydrogen-deficient binary. The hydrogen-deficient binary stars all show weak C-lines. The remaining stars in the sample are C-strong extreme-helium (EHe) stars and did not show large-amplitude velocity variations. Small-amplitude radial velocity variations known to be present amongst the EHe stars are largely undetected. Evidence for variability is, however, present in the known variable V2076 Oph (HD 160641) and in LS IV - 1 0 2 with amplitudes between 10 and 20 km s -1 . (author)

  16. Electric vortex in MHD flow

    International Nuclear Information System (INIS)

    Garcia, M.

    1995-01-01

    An electric vortex is the circulation of electron space charge about a magnetic field line that is transported by ion momentum. In cold, or low β flow the vortex diameter is the minimum length scale of charge neutrality. The distinctive feature of the vortex is its radial electric field which manifests the interplay of electrostatics, magnetism, and motion

  17. Radial transport of storm time ring current ions

    Science.gov (United States)

    Lui, A. T. Y.

    1993-01-01

    Radial transport of energetic ions for the development of the main phase of geomagnetic storms is investigated with data from the medium energy particle analyzer (MEPA) on the Charge Composition Explorer spacecraft, which monitored protons, helium ions, and the carbon-nitrogen-oxygen group, which is mostly dominated by oxygen ions. From a study of four geomagnetic storms, we show that the flux increase of these ions in the inner ring current region can be accounted for by an inward displacement of the ring current population by 0.5 to 3.5 R(E). There is a general trend that a larger inward displacement occurs at higher L shells than at lower ones. These results are in agreement with previous findings. The radially injected population consists of the prestorm population modified by substorm injections which occur on a much shorter time scale than that for a storm main phase. It is also found that the inward displacement is relatively independent of ion mass and energy, suggesting that the radial transport of these energetic ions is effected primarily by convective motion from a large electric field or by diffusion resulting from magnetic field fluctuations.

  18. Magnetic Decoupling Design and Experimental Validation of a Radial-Radial Flux Compound-Structure Permanent-Magnet Synchronous Machine for HEVs

    Directory of Open Access Journals (Sweden)

    Zhiyi Song

    2012-10-01

    Full Text Available The radial-radial flux compound-structure permanent-magnet synchronous machine (CS-PMSM, integrated by two concentrically arranged permanent-magnet electric machines, is an electromagnetic power-splitting device for hybrid electric vehicles (HEVs. As the two electric machines share a rotor as structural and magnetic common part, their magnetic paths are coupled, leading to possible mutual magnetic-field interference and complex control. In this paper, a design method to ensure magnetic decoupling with minimum yoke thickness of the common rotor is investigated. A prototype machine is designed based on the proposed method, and the feasibility of magnetic decoupling and independent control is validated by experimental tests of mutual influence. The CS-PMSM is tested by a designed driving cycle, and functions to act as starter motor, generator and to help the internal combustion engine (ICE operate at optimum efficiency are validated.

  19. A sensitive search for a muon electric dipole moment

    International Nuclear Information System (INIS)

    Semertzidis, Yannis K.; Carey, R.M.; Miller, J.P.; Rind, O.; Roberts, B.L.; Sulak, L.R.; Brown, H.; Danby, G.T.; Jackson, J.W.; Larsen, R.; Lazarus, D.M.; Meng, W.; Morse, W.M.; Ozben, C.S.; Prigl, R.; Semertzidis, Y.K.; Balakin, V.; Bazhan, A.; Dudnikov, A.; Khazin, B. I.

    2001-01-01

    We are proposing a new method to carry out a dedicated search for a permanent electric dipole moment (EDM) of the muon with a sensitivity at a level of 10 -24 e·cm. The experiment will be sensitive to non-standard physics like SUSY. The experimental design exploits the strong motional electric field sensed by relativistic particles in a magnetic storage ring. As a key feature, a novel technique has been invented in which the g-2 precession is compensated with a radial electric field. The EDM signature will be an out of plane muon spin precession as a function of time. The rate of this precession will be proportional to the EDM amplitude of the muon

  20. Radial pattern of nuclear decay processes

    International Nuclear Information System (INIS)

    Iskra, W.; Mueller, M.; Rotter, I.; Technische Univ. Dresden

    1994-05-01

    At high level density of nuclear states, a separation of different time scales is observed (trapping effect). We calculate the radial profile of partial widths in the framework of the continuum shell model for some 1 - resonances with 2p-2h nuclear structure in 16 O as a function of the coupling strength to the continuum. A correlation between the lifetime of a nuclear state and the radial profile of the corresponding decay process is observed. We conclude from our numerical results that the trapping effect creates structures in space and time characterized by a small radial extension and a short lifetime. (orig.)

  1. Experimental observation of the inductive electric field and related plasma nonuniformity in high frequency capacitive discharge

    International Nuclear Information System (INIS)

    Ahn, S. K.; Chang, H. Y.

    2008-01-01

    To elucidate plasma nonuniformity in high frequency capacitive discharges, Langmuir probe and B-dot probe measurements were carried out in the radial direction in a cylindrical capacitive discharge driven at 90 MHz with argon pressures of 50 and 400 mTorr. Through the measurements, a significant inductive electric field (i.e., time-varying magnetic field) was observed at the radial edge, and it was found that the inductive electric field creates strong plasma nonuniformity at high pressure operation. The plasma nonuniformity at high pressure operation is physically similar to the E-H mode transition typically observed in inductive discharges. This result agrees well with the theories of electromagnetic effects in large area and/or high frequency capacitive discharges

  2. Numerical model for radial transport in the ELMO Bumpy Torus

    International Nuclear Information System (INIS)

    Jaeger, E.F.; Hedrick, C.L.

    1977-11-01

    Neutral and charged particle densities and temperatures are calculated as functions of radius for the toroidal plasma in the ELMO Bumpy Torus (EBT) experiment. Energy dependent ionization and charge-exchange rates, ambipolar diffusion, and self-consistent radial electric field profiles are included. Variation in magnetic field due to finite plasma pressure, effects of energetic electron rings, and transport due to drift waves and magnetic field errors are neglected. Diffusion is assumed to be neoclassical with enhanced losses at low collisionalities. The model reproduces many of the observed features of EBT operation in the quiescent toroidal (T) mode. The self-consistently calculated electric field is everywhere positive (not as in experiments) unless enhanced electron collisionality is included. Solutions for advanced EBT's are obtained and confinement parameters predicted

  3. High conductivity carbon nanotube wires from radial densification and ionic doping

    Science.gov (United States)

    Alvarenga, Jack; Jarosz, Paul R.; Schauerman, Chris M.; Moses, Brian T.; Landi, Brian J.; Cress, Cory D.; Raffaelle, Ryne P.

    2010-11-01

    Application of drawing dies to radially densify sheets of carbon nanotubes (CNTs) into bulk wires has shown the ability to control electrical conductivity and wire density. Simultaneous use of KAuBr4 doping solution, during wire drawing, has led to an electrical conductivity in the CNT wire of 1.3×106 S/m. Temperature-dependent electrical measurements show that conduction is dominated by fluctuation-assisted tunneling, and introduction of KAuBr4 significantly reduces the tunneling barrier between individual nanotubes. Ultimately, the concomitant doping and densification process leads to closer packed CNTs and a reduced charge transfer barrier, resulting in enhanced bulk electrical conductivity.

  4. Radial pseudoaneurysm following diagnostic coronary angiography

    Directory of Open Access Journals (Sweden)

    Shankar Laudari

    2015-06-01

    Full Text Available The radial artery access has gained popularity as a method of diagnostic coronary catheterization compared to femoral artery puncture in terms of vascular complications and early ambulation. However, very rare complication like radial artery pseudoaneurysm may occur following cardiac catheterization which may give rise to serious consequences. Here, we report a patient with radial pseudoaneurysm following diagnostic coronary angiography. Adequate and correct methodology of compression of radial artery following puncture for maintaining hemostasis is the key to prevention.DOI: http://dx.doi.org/10.3126/jcmsn.v10i3.12776 Journal of College of Medical Sciences-Nepal, 2014, Vol-10, No-3, 48-50

  5. [Occupational risk factors for radial tunnel syndrome in factory workers].

    Science.gov (United States)

    Roquelaure, Y; Raimbeau, G; Saint-Cast, Y; Martin, Y H; Pelier-Cady, M C

    2003-12-01

    The purpose of the study was to evaluate the professional and extraprofessional risk factors for radial tunnel syndrome (RTS) in employees of three large companies. Twenty-one cases of RTS were compared to 21 controls, matched for age, sex, and activity. In nine cases, RTS was associated with carpal tunnel syndrome. The analysis considered medical history, extraprofessional activity, and the ergonomic and organisational aspects of work. The study demonstrated three risk factors of RTS related to work conditions. The regular use of a force of at least 1 kg (OR = 9.1 (1.4-56.9)) more than 10 times per hour is the main biomechanical risk factor. Static work (OR = 5.9 (1.2-29.9)) as well as work with the elbow constantly extended 0 degree to 45 degrees, is strongly associated with an increased risk of RTS (OR = 4.9 (1.0-25.0)). Complete extension of the elbow associated with pronation and supination of the forearm may cause trauma to the radial nerve in the radial tunnel. On the other hand, we found no personal factors and no extraprofessional activities which were associated with an increased risk of RTS. This study shows that motions of the forearm requiring intense effort and performed with the elbow in extension and the forearm in pronation and supination increase the risk of RTS.

  6. Adaptive control of the radial servo system of a compact disc player

    NARCIS (Netherlands)

    Draijer, W.; Steinbuch, M.; Bosgra, O.H.

    1992-01-01

    The radial servo system of a compact disc player has to cope with large gain variations which are due to disc dependent optical characteristics, tolerances in mechanical and electrical components and nonlinearity in the generation of the position index. In current players this problem has been

  7. Radial transport with perturbed magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Hazeltine, R. D. [Institute for Fusion Studies, University of Texas at Austin, Austin, Texas 78712 (United States)

    2015-05-15

    It is pointed out that the viscosity coefficient describing radial transport of toroidal angular momentum is proportional to the second power of the gyro-radius—like the corresponding coefficients for particle and heat transport—regardless of any geometrical symmetry. The observation is widely appreciated, but worth emphasizing because some literature gives the misleading impression that asymmetry can allow radial moment transport in first-order.

  8. Radial transport with perturbed magnetic field

    International Nuclear Information System (INIS)

    Hazeltine, R. D.

    2015-01-01

    It is pointed out that the viscosity coefficient describing radial transport of toroidal angular momentum is proportional to the second power of the gyro-radius—like the corresponding coefficients for particle and heat transport—regardless of any geometrical symmetry. The observation is widely appreciated, but worth emphasizing because some literature gives the misleading impression that asymmetry can allow radial moment transport in first-order

  9. Stability of radial and non-radial pulsation modes of massive ZAMS models

    International Nuclear Information System (INIS)

    Odell, A.P.; Pausenwein, A.; Weiss, W.W.; Hajek, A.

    1987-01-01

    The authors have computed non-adiabatic eigenvalues for radial and non-radial pulsation modes of star models between 80 and 120 M solar with composition of chi=0.70 and Z=0.02. The radial fundamental mode is unstable in models with mass greater than 95 M solar , but the first overtone mode is always stable. The non-radial modes are all stable for all models, but the iota=2 f-mode is the closest to being driven. The non-radial modes are progressively more stable with higher iota and with higher n (for both rho- and g-modes). Thus, their results indicate that radial pulsation limits the upper mass of a star

  10. Dynamical interplay between fluctuations, electric fields and transport in fusion plasmas

    International Nuclear Information System (INIS)

    Hidalgo, C.; Pedrosa, M.A.; Goncalves, B.

    2003-01-01

    A view of recent experimental results and progress in the characterization of the statistical properties of electrostatic turbulence in magnetically confined devices is given. An empirical similarity in the scaling properties of the probability distribution function (PDF) of turbulent transport has been observed in the plasma edge region in fusion plasmas. The investigation of the dynamical interplay between fluctuation in gradients, turbulent transport and radial electric fields has shows that these parameters are strongly coupled both in tokamak and stellarator plasmas. The bursty behaviour of turbulent transport is linked with a departure from the most probable radial gradient. The dynamical relation between fluctuations in gradients and transport is strongly affected by the presence of sheared poloidal flows which organized themselves near marginal stability. These results emphasize the importance of the statistical description of transport processes in fusion plasmas as an alternative approach to the traditional way to characterize transport based on the computation of effective transport coefficients. (author)

  11. Effects of relativistic small radial component on atomic photoionization cross sections

    International Nuclear Information System (INIS)

    Liu Xiaobin; Xing Yongzhong; Sun Xiaowei

    2008-01-01

    The effects of relativistic small radial component on atomic photoionization cross sections have been studied within relativistic average self-consistent field theory. Relativistic effects are relatively unimportant for low photon energy, along with a review of high-energy photoionization the relativistic effects are quite important. The effects of relativistic small radial component on photoionization process should show breakdown when the nuclear finite-size effects is taken into account. The compression of wavefunction into the space near nucleus is so strong in highly charged ions that the electronic radius greatly decreases, and the effects of relativistic small radial component on photoionization cross sections turn to stronger than ordinary atoms. Since relativistic effects are extremely sensitive to the behavior of small radial component, the results are in good agreement with relativistic effects on photoionization cross section. (authors)

  12. 21 CFR 866.4800 - Radial immunodiffusion plate.

    Science.gov (United States)

    2010-04-01

    ...) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Immunology Laboratory Equipment and Reagents § 866.4800 Radial immunodiffusion plate. (a) Identification. A radial immunodiffusion plate for clinical use...

  13. Numerical Simulation of Neoclassical Currents, Parallel Viscosity, and Radial Current Balance in Tokamak Plasmas

    International Nuclear Information System (INIS)

    Kiviniemi, T.

    2001-01-01

    One of the principal problems en route to a fusion reactor is that of insufficient plasma confinement, which has lead to both theoretical and experimental research into transport processes in the parameter range relevant for fusion energy production. The neoclassical theory of tokamak transport is well-established unlike the theory of turbulence driven anomalous transport in which extensive progress has been made during last few years. So far, anomalous transport has been dominant in experiments, but transport may be reduced to the neoclassical level in advanced tokamak scenarios. This thesis reports a numerical study of neoclassical fluxes, parallel viscosity, and neoclassical radial current balance in tokamaks. Neoclassical parallel viscosity and particle fluxes are simulated over a wide range of collisionalities, using the fully kinetic five-dimensional neoclassical orbit-following Monte Carlo code ASCOT. The qualitative behavior of parallel viscosity derived in earlier analytic models is shown to be incorrect for high poloidal Mach numbers. This is because the poloidal dependence of density was neglected. However, in high Mach number regime, it is the convection and compression terms, rather than the parallel viscosity term, that are shown to dominate the momentum balance. For fluxes, a reasonable agreement between numerical and analytical results is found in the collisional parameter regime. Neoclassical particle fluxes are additionally studied in the banana regime using the three-dimensional Fokker-Planck code DEPORA, which solves the drift-kinetic equation with finite differencing. Limitations of the small inverse aspect ratio approximation adopted in the analytic theory are addressed. Assuming that the anomalous transport is ambipolar, the radial electric field and its shear at the tokamak plasma edge can be solved from the neoclassical radial current balance. This is performed both for JET and ASDEX Upgrade tokamaks using the ASCOT code. It is shown that

  14. Testing strong interaction theories

    International Nuclear Information System (INIS)

    Ellis, J.

    1979-01-01

    The author discusses possible tests of the current theories of the strong interaction, in particular, quantum chromodynamics. High energy e + e - interactions should provide an excellent means of studying the strong force. (W.D.L.)

  15. Access of energetic particles to storm time ring current through enhanced radial diffusion

    International Nuclear Information System (INIS)

    Lyons, L.R.; Schulz, M.

    1989-01-01

    Magnetic storms are distinguishable from other periods of geomagnetic activity by the injection of trapped electrons and ions to the 2 approx-lt L approx-lt 4 region. It has been proposed previously that this injection results from an inward displacement of the preexisting trapped-particle population by enhanced storm time electric fields. However, high-energy (approx-gt 40 keV) ring-current particles have drift periods that are typically shorter than the time of the main-phase development, and so the direct radial transport of these particles is restricted. The authors propose here that the transport of approx-gt 40 keV particles into the storm time ring current can result from enhanced stochastic radial transport driven by fluctuating electric fields during a storm's main phase. They estimate the effects of such electric fields by applying radial-diffusion theory, assuming a preexisting trapped-particle population as the initial conditions, and they demonstrate the feasibility of explaining observed flux increases of approx-gt 40-keV particles at L approx-lt 4 by enhanced radial diffusion. It is necessary that new particles be injected near the outer boundary of the trapping region so as to maintain the fluxes there as an outer boundary condition, and they estimate that the approx-gt 40-keV portion of the storm time ring current at L ∼ 3 consists of about 50% preexisting and about 50% new particles. They thus find that formation of the storm time ring current may be explainable via a combination of direct radial transport at energies approx-lt 40 keV and diffusive radial transport at higher energies

  16. Apparent resistivity for transient electromagnetic induction logging and its correction in radial layer identification

    Science.gov (United States)

    Meng, Qingxin; Hu, Xiangyun; Pan, Heping; Xi, Yufei

    2018-04-01

    We propose an algorithm for calculating all-time apparent resistivity from transient electromagnetic induction logging. The algorithm is based on the whole-space transient electric field expression of the uniform model and Halley's optimisation. In trial calculations for uniform models, the all-time algorithm is shown to have high accuracy. We use the finite-difference time-domain method to simulate the transient electromagnetic field in radial two-layer models without wall rock and convert the simulation results to apparent resistivity using the all-time algorithm. The time-varying apparent resistivity reflects the radially layered geoelectrical structure of the models and the apparent resistivity of the earliest time channel follows the true resistivity of the inner layer; however, the apparent resistivity at larger times reflects the comprehensive electrical characteristics of the inner and outer layers. To accurately identify the outer layer resistivity based on the series relationship model of the layered resistance, the apparent resistivity and diffusion depth of the different time channels are approximately replaced by related model parameters; that is, we propose an apparent resistivity correction algorithm. By correcting the time-varying apparent resistivity of radial two-layer models, we show that the correction results reflect the radially layered electrical structure and the corrected resistivities of the larger time channels follow the outer layer resistivity. The transient electromagnetic fields of radially layered models with wall rock are simulated to obtain the 2D time-varying profiles of the apparent resistivity and corrections. The results suggest that the time-varying apparent resistivity and correction results reflect the vertical and radial geoelectrical structures. For models with small wall-rock effect, the correction removes the effect of the low-resistance inner layer on the apparent resistivity of the larger time channels.

  17. Anomalies of radial and ulnar arteries

    Directory of Open Access Journals (Sweden)

    Rajani Singh

    Full Text Available Abstract During dissection conducted in an anatomy department of the right upper limb of the cadaver of a 70-year-old male, both origin and course of the radial and ulnar arteries were found to be anomalous. After descending 5.5 cm from the lower border of the teres major, the brachial artery anomalously bifurcated into a radial artery medially and an ulnar artery laterally. In the arm, the ulnar artery lay lateral to the median nerve. It followed a normal course in the forearm. The radial artery was medial to the median nerve in the arm and then, at the level of the medial epicondyle, it crossed from the medial to the lateral side of the forearm, superficial to the flexor muscles. The course of the radial artery was superficial and tortuous throughout the arm and forearm. The variations of radial and ulnar arteries described above were associated with anomalous formation and course of the median nerve in the arm. Knowledge of neurovascular anomalies are important for vascular surgeons and radiologists.

  18. Rydberg atoms in strong fields

    International Nuclear Information System (INIS)

    Kleppner, D.; Tsimmerman, M.

    1985-01-01

    Experimental and theoretical achievements in studying Rydberg atoms in external fields are considered. Only static (or quasistatic) fields and ''one-electron'' atoms, i.e. atoms that are well described by one-electron states, are discussed. Mainly behaviour of alkali metal atoms in electric field is considered. The state of theoretical investigations for hydrogen atom in magnetic field is described, but experimental data for atoms of alkali metals are presented as an illustration. Results of the latest experimental and theoretical investigations into the structure of Rydberg atoms in strong fields are presented

  19. Manipulation of positron orbits in a dipole magnetic field with fluctuating electric fields

    Science.gov (United States)

    Saitoh, H.; Horn-Stanja, J.; Nißl, S.; Stenson, E. V.; Hergenhahn, U.; Pedersen, T. Sunn; Singer, M.; Dickmann, M.; Hugenschmidt, C.; Stoneking, M. R.; Danielson, J. R.; Surko, C. M.

    2018-01-01

    We report the manipulation of positron orbits in a toroidal dipole magnetic field configuration realized with electric fields generated by segmented electrodes. When the toroidal circulation motion of positrons in the dipole field is coupled with time-varying electric fields generated by azimuthally segmented outer electrodes, positrons undergo oscillations of their radial positions. This enables quick manipulation of the spatial profiles of positrons in a dipole field trap by choosing appropriate frequency, amplitude, phase, and gating time of the electric fields. According to numerical orbit analysis, we applied these electric fields to positrons injected from the NEPOMUC slow positron facility into a prototype dipole field trap experiment with a permanent magnet. Measurements with annihilation γ-rays clearly demonstrated the efficient compression effects of positrons into the strong magnetic field region of the dipole field configuration. This positron manipulation technique can be used as one of essential tools for future experiments on the formation of electron-positron plasmas.

  20. Non-linear radial spinwave modes in thin magnetic disks

    International Nuclear Information System (INIS)

    Helsen, M.; De Clercq, J.; Vansteenkiste, A.; Van Waeyenberge, B.; Gangwar, A.; Back, C. H.; Weigand, M.

    2015-01-01

    We present an experimental investigation of radial spin-wave modes in magnetic nano-disks with a vortex ground state. The spin-wave amplitude was measured using a frequency-resolved magneto-optical spectrum analyzer, allowing for high-resolution resonance curves to be recorded. It was found that with increasing excitation amplitude up to about 10 mT, the lowest-order mode behaves strongly non-linearly as the mode frequency redshifts and the resonance peak strongly deforms. This behavior was quantitatively reproduced by micromagnetic simulations. Micromagnetic simulations showed that at higher excitation amplitudes, the spinwaves are transformed into a soliton by self-focusing, and collapse onto the vortex core, dispersing the energy in short-wavelength spinwaves. Additionally, this process can lead to switching of the vortex polarization through the injection of a Bloch point

  1. Are Titan's radial Labyrinth terrains surface expressions of large laccoliths?

    Science.gov (United States)

    Schurmeier, L.; Dombard, A. J.; Malaska, M.; Radebaugh, J.

    2017-12-01

    The Labyrinth terrain unit may be the one of the best examples of the surface expression of Titan's complicated history. They are characterized as highly eroded, dissected, and elevated plateaus and remnant ridges, with an assumed composition that is likely organic-rich based on radar emissivity. How these features accumulated organic-rich sediments and formed topographic highs by either locally uplifting or surviving pervasive regional deflation or erosion is an important question for understanding the history of Titan. There are several subsets of Labyrinth terrains, presumably with differing evolutionary histories and formation processes. We aim to explain the formation of a subset of Labyrinth terrain units informally referred to as "radial Labyrinth terrains." They are elevated and appear dome-like, circular in planform, have a strong radial dissection pattern, are bordered by Undifferentiated Plains units, and are found in the mid-latitudes. Based on their shape, clustering, and dimensions, we suggest that they may be the surface expression of large subsurface laccoliths. A recent study by Manga and Michaut (Icarus, 2017) explained Europa's lenticulae (pits, domes, spots) with the formation of saucer-shaped sills that form laccoliths around the brittle-ductile transition depth within the ice shell (1-5 km). Here, we apply the same scaling relationships and find that the larger size of radial labyrinth terrains with Titan's higher gravity implies deeper intrusion depths of around 20-40 km. This intrusion depth matches the expected brittle-ductile transition on Titan based on our finite element simulations and yield strength envelope analyses. We hypothesize that Titan's radial labyrinth terrains formed as cryovolcanic (water) intrusions that rose to the brittle-ductile transition within the ice shell where they spread horizontally, and uplifted the overlying ice. The organic-rich sedimentary cover also uplifted, becoming more susceptible to pluvial and fluvial

  2. Manufacturing of Precision Forgings by Radial Forging

    International Nuclear Information System (INIS)

    Wallner, S.; Harrer, O.; Buchmayr, B.; Hofer, F.

    2011-01-01

    Radial forging is a multi purpose incremental forging process using four tools on the same plane. It is widely used for the forming of tool steels, super alloys as well as titanium- and refractory metals. The range of application goes from reducing the diameters of shafts, tubes, stepped shafts and axels, as well as for creating internal profiles for tubes in Near-Net-Shape and Net-Shape quality. Based on actual development of a weight optimized transmission input shaft, the specific features of radial forging technology is demonstrated. Also a Finite Element Model for the simulation of the process is shown which leads to reduced pre-processing effort and reduced computing time compared to other published simulation methods for radial forging. The finite element model can be applied to quantify the effects of different forging strategies.

  3. Suppression and excitation of MHD activity with an electrically polarized electrode at the TCABR tokamak plasma edge

    International Nuclear Information System (INIS)

    Nascimento, I.C.; Kuznetsov, Yu.K.; Guimaraes-Filho, Z.O.; Chamaa-Neto, I. El; Usuriaga, O.; Fonseca, A.M.M.; Galvao, R.M.O.; Caldas, I.L.; Severo, J.H.F.; Semenov, I.B.; Ribeiro, C.; Heller, M.V.P.; Bellintani, V.; Elizondo, J.I.; Sanada, E.

    2007-01-01

    Two reproducible regimes of tokamak operation, with excitation or suppression of MHD activity can be obtained using a voltage-biased electrode inside the edge of the TCABR tokamak. The experiment was carried out adjusting the tokamak parameters to obtain two types of discharges: with strong or weak MHD activity, without biasing in both cases. The plasma current was adjusted to cover a range of safety factor from 2.9 up to 3.5, so that when biasing was applied the magnetic island (3,1) could interact with the edge barrier. The application of biasing in subsequent discharges of each type resulted in excitation or suppression of the MHD activity. The results show that the dominant modes are m = 2, n = 1 and m = 3, n = 1 for excitation and partial suppression, respectively. In both regimes a strong decrease in the radial electric field is detected with destruction of the transport barrier and of the improved confinement caused by different mechanisms. The measurements include temporal behaviour of edge transport, turbulence, poloidal electric and magnetic fields, edge density, radial electric fields and radial profile of H α line intensity. The explanation of the excitation and suppression processes is discussed in the paper

  4. The Matlab Radial Basis Function Toolbox

    Directory of Open Access Journals (Sweden)

    Scott A. Sarra

    2017-03-01

    Full Text Available Radial Basis Function (RBF methods are important tools for scattered data interpolation and for the solution of Partial Differential Equations in complexly shaped domains. The most straight forward approach used to evaluate the methods involves solving a linear system which is typically poorly conditioned. The Matlab Radial Basis Function toolbox features a regularization method for the ill-conditioned system, extended precision floating point arithmetic, and symmetry exploitation for the purpose of reducing flop counts of the associated numerical linear algebra algorithms.

  5. Radial velocity observations of VB10

    Science.gov (United States)

    Deshpande, R.; Martin, E.; Zapatero Osorio, M. R.; Del Burgo, C.; Rodler, F.; Montgomery, M. M.

    2011-07-01

    VB 10 is the smallest star known to harbor a planet according to the recent astrometric study of Pravdo & Shaklan [1]. Here we present near-infrared (J-band) radial velocity of VB 10 performed from high resolution (R~20,000) spectroscopy (NIRSPEC/KECK II). Our results [2] suggest radial velocity variability with amplitude of ~1 km/s, a result that is consistent with the presence of a massive planet companion around VB10 as found via long-term astrometric monitoring of the star by Pravdo & Shaklan. Employing an entirely different technique we verify the results of Pravdo & Shaklan.

  6. Plasma Signatures of Radial Field Power Dropouts

    International Nuclear Information System (INIS)

    Lucek, E.A.; Horbury, T.S.; Balogh, A.; McComas, D.J.

    1998-01-01

    A class of small scale structures, with a near-radial magnetic field and a drop in magnetic field fluctuation power, have recently been identified in the polar solar wind. An earlier study of 24 events, each lasting for 6 hours or more, identified no clear plasma signature. In an extension of that work, radial intervals lasting for 4 hours or more (89 in total), have been used to search for a statistically significant plasma signature. It was found that, despite considerable variations between intervals, there was a small but significant drop, on average, in plasma temperature, density and β during these events

  7. Reble, a radially converging electron beam accelerator

    International Nuclear Information System (INIS)

    Ramirez, J.J.; Prestwich, K.R.

    1976-01-01

    The Reble accelerator at Sandia Laboratories is described. This accelerator was developed to provide an experimental source for studying the relevant diode physics, beam propagation, beam energy deposition in a gas using a radially converging e-beam. The nominal parameters for Reble are 1 MV, 200 kA, 20 ns e-beam pulse. The anode and cathode are concentric cylinders with the anode as the inner cylinder. The radial beam can be propagated through the thin foil anode into the laser gas volume. The design and performance of the various components of the accelerator are presented

  8. Electricity from wetlands

    NARCIS (Netherlands)

    Wetser, K.

    2016-01-01

    <strong>Sustainable electricity generation by the plant microbial fuel cellstrong>

    Fossil fuels are currently the main source of electricity production. Combustion of fossil fuels causes air pollution severely affecting human health and nature. This results in an increasing demand for

  9. Experimental Characterization of Piezoelectric Radial Field Diaphragms for Fluidic Control

    Science.gov (United States)

    Bryant, R. G.; Kavli, S. E.; Thomas, R. A., Jr.; Darji, K. J.; Mossi, K. M.

    2004-01-01

    NASA has recently developed a new piezoelectric actuator, the Radial Field Diaphragm or RFD. This actuator uses a radially-directed electric field to generate concentric out-of-plane (Z-axis) motion that allows this packaged device to be used as a pump or valve diaphragm. In order to efficiently use this new active device, experimental determination of pressure, flow rate, mechanical work, power consumption and overall efficiency needs to be determined by actually building a pump. However, without an optimized pump design, it is difficult to assess the quality of the data, as these results are inherent to the actual pump. Hence, separate experiments must be conducted in order to generate independent results to help guide the design criteria and pump quality. This paper focuses on the experiments used to generate the RFD's operational parameters and then compares these results to the experimentally determined results of several types of ball pumps. Also discussed are how errors are inherently introduced into the experiments, the pump design, experimental hardware and their effects on the overall system efficiency.

  10. Radiographic loss of contact between radial head fracture fragments is moderately reliable

    NARCIS (Netherlands)

    Bruinsma, Wendy E.; Guitton, Thierry; Ring, David; Eng, Kevin; Jokhi, Vispi; Oloruntoba, David O.; Jain, Sanjev; Melvanki, Parag; Frihagen, Frede; McGraw, Iain; Lenzlinger, Philipp; Ponsen, K. J.; Schmidt, Andrew; Ciritsis, Bernhard; Conflitti, Joseph M.; Turina, Matthias; Poolman, Rudolf W.; Liem, Ronald; Gulve, R. S.; Wagg, James; Kloen, Peter; Grosso, Elena; Mormino, Matt; Choudhari, Pradeep; Zura, Robert D.; Pesantez, Rodrigo; Thomas, George; Brink, Peter; Swiontkowski, Marc; Beingessner, Daphne; Schep, Niels; Kanakaris, Nikolaos; Peters, R. W.; Andrew, J.; Trenholm, I.; Mica, Ladislav; Verhofstad, M. H. J.; Taitsman, Lisa; Hernandez, Daniel; Harris, Ian; Egol, Kenneth; Jeray, Kyle; Borris, Lars C.; Barquet, Antonio; Kellam, James; Marsh, John L.; Hobby, Jonathan L.; Eygendaal, Denise; Goslings, J. C.; Kleinlugtenbelt, I. J. V.

    2014-01-01

    Loss of contact between radial head fracture fragments is strongly associated with other elbow or forearm injuries. If this finding has adequate interobserver reliability, it could help examiners identify and treat associated ligament injuries and fractures (eg, forearm interosseous ligament injury

  11. Feasibility tests of a high resolution sampling radial drift chamber

    International Nuclear Information System (INIS)

    Huth, J.

    1985-01-01

    The design concept and results of feasibility tests for a vertex detector intended for use in the TPC-PEP4/9 experiment are presented. The detector is based on a slow radial drift in dimethyl ether. High resolution localization of the avalanches at the sense wire is accomplished with nearby pickup wires and the utilization of waveform sampling electronics. The avalanche angular coordinate measurements, combined with knowledge of the electric field distribution and drift velocity permit reconstruction of the trajectory using essentially all track information. Measurements with a test chamber constructed to study characteristics of avalanche localization indicate that the recoverable track information in one centimeter of dimethyl ether at 1.5 atm is equivalent to 30 measurements of 40 μm accuracy. (orig.)

  12. Microinstabilities in a radially contracting inhomogeneous cylindrical plasma slab

    International Nuclear Information System (INIS)

    Deutsch, R.; Kaeppeler, H.J.

    1980-07-01

    In order to study the development of microinstabilities in a collapsing cylindrical plasma sheath, corresponding to the situations in a z-pinch or a plasma focus, the dispersion relation for electromagnetic perturbations is derived with the aid of a newly established slab-model for an inhomogeneous, radially contracting plasma. In contrast to previously used slab-models, the orientation of the electric field is in direction of the cylinder axis and the azimuthal magnetic field is induced by the current flowing through the cylindrical plasma slab. The Vlasov equation is used together with the Krook collision term in order to include the influence of collisions. The results of this theory presented in this report will be used to calculate the growth of drift instabilities in the compression phase of a plasma focus, and shall serve as a basis for further development of a more general dispersion relation including runaway-effects. (orig.)

  13. Abortion: Strong's counterexamples fail

    DEFF Research Database (Denmark)

    Di Nucci, Ezio

    2009-01-01

    This paper shows that the counterexamples proposed by Strong in 2008 in the Journal of Medical Ethics to Marquis's argument against abortion fail. Strong's basic idea is that there are cases--for example, terminally ill patients--where killing an adult human being is prima facie seriously morally...

  14. Strong Langmuir turbulence

    International Nuclear Information System (INIS)

    Goldman, M.V.

    1984-01-01

    After a brief discussion of beam-excited Langmuir turbulence in the solar wind, we explain the criteria for wave-particle, three-wave and strong turbulence interactions. We then present the results of a numerical integration of the Zakharov equations, which describe the strong turbulence saturation of a weak (low-density) high energy, bump-on-tail beam instability. (author)

  15. On helicon wave induced radial plasma transport

    International Nuclear Information System (INIS)

    Petrzilka, V.

    1993-04-01

    Estimates of helicon wave induced radial plasma transport are presented. The wave induced transport grows or decreases in dependence on the sign of the azimuthal wave number; these changes in transport may play an important role in helicon wave plasma sources. (author) 5 figs., 18 refs

  16. Revealing the radial modes in vortex beams

    CSIR Research Space (South Africa)

    Sephton, Bereneice C

    2016-10-01

    Full Text Available Light beams that carry orbital angular momentum are often approximated by modulating an initial beam, usually Gaussian, with an azimuthal phase variation to create a vortex beam. Such vortex beams are well defined azimuthally, but the radial profile...

  17. Measurement of Wear in Radial Journal Bearings

    NARCIS (Netherlands)

    Ligterink, D.J.; Ligterink, D.J.; de Gee, A.W.J.

    1996-01-01

    this article, the measurement of wear in radial journal bearings is discussed, where a distinction is made between stationary and non-stationary contact conditions. Starting with Holm/Archard's wear law, equations are derived for the calculation of the specific wear rate k of the bearing material as

  18. Radial transfer effects for poloidal rotation

    Science.gov (United States)

    Hallatschek, Klaus

    2010-11-01

    Radial transfer of energy or momentum is the principal agent responsible for radial structures of Geodesic Acoustic Modes (GAMs) or stationary Zonal Flows (ZF) generated by the turbulence. For the GAM, following a physical approach, it is possible to find useful expressions for the individual components of the Poynting flux or radial group velocity allowing predictions where a mathematical full analysis is unfeasible. Striking differences between up-down symmetric flux surfaces and asymmetric ones have been found. For divertor geometries, e.g., the direction of the propagation depends on the sign of the ion grad-B drift with respect to the X-point, reminiscent of a sensitive determinant of the H-mode threshold. In nonlocal turbulence computations it becomes obvious that the linear energy transfer terms can be completely overwhelmed by the action of the turbulence. In contrast, stationary ZFs are governed by the turbulent radial transfer of momentum. For sufficiently large systems, the Reynolds stress becomes a deterministic functional of the flows, which can be empirically determined from the stress response in computational turbulence studies. The functional allows predictions even on flow/turbulence states not readily obtainable from small amplitude noise, such as certain transport bifurcations or meta-stable states.

  19. Spectral problem for the radial Schroedinger equation

    International Nuclear Information System (INIS)

    Vshivtsev, A.S.; Tatarintsev, A.V.; Prokopov, A.V.; Sorokin, V. N.

    1998-01-01

    For the first time, a procedure for determining spectra on the basis of generalized integral transformations is implemented for a wide class of radial Schroedinger equations. It is shown that this procedure works well for known types of potentials. Concurrently, this method makes it possible to obtain new analytic results for the Cornell potential. This may prove important for hadron physics

  20. Computing modal dispersion characteristics of radially Asymmetric ...

    African Journals Online (AJOL)

    We developed a matrix theory that applies to with non-circular/circular but concentric layers fibers. And we compute the dispersion characteristics of radially unconventional fiber, known as Asymmetric Bragg fiber. An attempt has been made to determine how the modal characteristics change as circular Bragg fiber is ...

  1. Measurement of electric fields in the H-1NF heliac

    International Nuclear Information System (INIS)

    James, B.W.; Howard, J.

    1999-01-01

    There are a number of laser induced fluorescence techniques which can be used to measure internal plasma electric fields. It is planned to use a technique based on Stark mixing of energy levels in a supersonic beam containing metastable helium atoms to measure radial electric fields in H-1NF. Enhanced values of radial electric field are associated with improved confinement modes in H-1NF and other magnetically confined plasmas

  2. Variations in the usage and composition of a radial cocktail during radial access coronary angiography procedures.

    LENUS (Irish Health Repository)

    Pate, G

    2011-10-01

    A survey was conducted of medication administered during radial artery cannulation for coronary angiography in 2009 in Ireland; responses were obtained for 15 of 20 centres, in 5 of which no radial access procedures were undertaken. All 10 (100%) centres which provided data used heparin and one or more anti-spasmodics; verapamil in 9 (90%), nitrate in 1 (10%), both in 2 (20%). There were significant variations in the doses used. Further work needs to be done to determine the optimum cocktail to prevent radial artery injury following coronary angiography.

  3. Radial wave crystals: radially periodic structures from anisotropic metamaterials for engineering acoustic or electromagnetic waves.

    Science.gov (United States)

    Torrent, Daniel; Sánchez-Dehesa, José

    2009-08-07

    We demonstrate that metamaterials with anisotropic properties can be used to develop a new class of periodic structures that has been named radial wave crystals. They can be sonic or photonic, and wave propagation along the radial directions is obtained through Bloch states like in usual sonic or photonic crystals. The band structure of the proposed structures can be tailored in a large amount to get exciting novel wave phenomena. For example, it is shown that acoustical cavities based on radial sonic crystals can be employed as passive devices for beam forming or dynamically orientated antennas for sound localization.

  4. Hybrid simulations of radial transport driven by the Rayleigh-Taylor instability

    Science.gov (United States)

    Delamere, P. A.; Stauffer, B. H.; Ma, X.

    2017-12-01

    Plasma transport in the rapidly rotating giant magnetospheres is thought to involve a centrifugally-driven flux tube interchange instability, similar to the Rayleigh-Taylor (RT) instability. In three dimensions, the convective flow patterns associated with the RT instability can produce strong guide field reconnection, allowing plasma mass to move radially outward while conserving magnetic flux (Ma et al., 2016). We present a set of hybrid (kinetic ion / fluid electron) plasma simulations of the RT instability using high plasma beta conditions appropriate for Jupiter's inner and middle magnetosphere. A density gradient, combined with a centrifugal force, provide appropriate RT onset conditions. Pressure balance is achieved by initializing two ion populations: one with fixed temperature, but varying density, and the other with fixed density, but a temperature gradient that offsets the density gradient from the first population and the centrifugal force (effective gravity). We first analyze two-dimensional results for the plane perpendicular to the magnetic field by comparing growth rates as a function of wave vector following Huba et al. (1998). Prescribed perpendicular wave modes are seeded with an initial velocity perturbation. We then extend the model to three dimensions, introducing a stabilizing parallel wave vector. Boundary conditions in the parallel direction prohibit motion of the magnetic field line footprints to model the eigenmodes of the magnetodisc's resonant cavity. We again compare growth rates based on perpendicular wave number, but also on the parallel extent of the resonant cavity, which fixes the size of the largest parallel wavelength. Finally, we search for evidence of strong guide field magnetic reconnection within the domain by identifying areas with large parallel electric fields or changes in magnetic field topology.

  5. A corotation electric field model of the Earth derived from Swarm satellite magnetic field measurements

    Science.gov (United States)

    Maus, Stefan

    2017-08-01

    Rotation of the Earth in its own geomagnetic field sets up a primary corotation electric field, compensated by a secondary electric field of induced electrical charges. For the geomagnetic field measured by the Swarm constellation of satellites, a derivation of the global corotation electric field inside and outside of the corotation region is provided here, in both inertial and corotating reference frames. The Earth is assumed an electrical conductor, the lower atmosphere an insulator, followed by the corotating ionospheric E region again as a conductor. Outside of the Earth's core, the induced charge is immediately accessible from the spherical harmonic Gauss coefficients of the geomagnetic field. The charge density is positive at high northern and southern latitudes, negative at midlatitudes, and increases strongly toward the Earth's center. Small vertical electric fields of about 0.3 mV/m in the insulating atmospheric gap are caused by the corotation charges located in the ionosphere above and the Earth below. The corotation charges also flow outward into the region of closed magnetic field lines, forcing the plasmasphere to corotate. The electric field of the corotation charges further extends outside of the corotating regions, contributing radial outward electric fields of about 10 mV/m in the northern and southern polar caps. Depending on how the magnetosphere responds to these fields, the Earth may carry a net electric charge.

  6. Analysis on Coupled Vibration of a Radially Polarized Piezoelectric Cylindrical Transducer

    Directory of Open Access Journals (Sweden)

    Jie Xu

    2017-12-01

    Full Text Available Coupled vibration of a radially polarized piezoelectric cylindrical transducer is analyzed with the mechanical coupling coefficient method. The method has been utilized to analyze the metal cylindrical transducer and the axially polarized piezoelectric cylindrical transducer. In this method, the mechanical coupling coefficient is introduced and defined as the stress ratio in different directions. Coupled vibration of the cylindrical transducer is regarded as the interaction of the plane radial vibration of a ring and the longitudinal vibration of a tube. For the radially polarized piezoelectric cylindrical transducer, the radial and longitudinal electric admittances as functions of mechanical coupling coefficients and angular frequencies are derived, respectively. The resonance frequency equations are obtained. The dependence of resonance frequency and mechanical coupling coefficient on aspect ratio is studied. Vibrational distributions on the surfaces of the cylindrical transducer are presented with experimental measurement. On the support of experiments, this work is verified and provides a theoretical foundation for the analysis and design of the radially polarized piezoelectric cylindrical transducer.

  7. Experimental and theoretical study of friction torque from radial ball bearings

    Science.gov (United States)

    Geonea, Ionut; Dumitru, Nicolae; Dumitru, Ilie

    2017-10-01

    In this paper it is presented a numerical simulation and an experimental study of total friction torque from radial ball bearings. For this purpose it is conceived a virtual CAD model of the experimental test bench for bearing friction torque measurement. The virtual model it is used for numerical simulation in Adams software, that allows dynamic study of multi-body systems and in particularly with facility Adams Machinery of dynamic behavior of machine parts. It is manufactured an experimental prototype of the test bench for radial ball bearings friction torque measurement. In order to measure the friction torque of the tested bearings it is used an equal resistance elastic beam element, with strain gauge transducer to measure bending deformations. The actuation electric motor of the bench has the shaft mounted on two bearings and the motor housing is fixed to the free side of the elastic beam, which is bended by a force proportional with the total friction torque. The beam elastic element with strain gauge transducer is calibrated in order to measure the force occurred. Experimental determination of the friction torque is made for several progressive radial loads. It is established the correlation from the friction torque and bearing radial load. The bench allows testing of several types and dimensions of radial bearings, in order to establish the bearing durability and of total friction torque.

  8. The effect of sequential coupling on radial displacement accuracy in electromagnetic inside-bead forming: simulation and experimental analysis using Maxwell and ABAQUS software

    Energy Technology Data Exchange (ETDEWEB)

    Chaharmiri, Rasoul; Arezoodar, Alireza Fallahi [Amirkabir University, Tehran (Iran, Islamic Republic of)

    2016-05-15

    Electromagnetic forming (EMF) is a high strain rate forming technology which can effectively deform and shape high electrically conductive materials at room temperature. In this study, the electromagnetic and mechanical parts of the process simulated using Maxwell and ABAQUS software, respectively. To provide a link between the software, two approaches include 'loose' and 'sequential' coupling were applied. This paper is aimed to investigate how sequential coupling would affect radial displacement accuracy, as an indicator of tube final shape, at various discharge voltages. The results indicated a good agreement for the both approaches at lower discharge voltages with more accurate results for sequential coupling, but at high discharge voltages, there was a non-negligible overestimation of about 43% for the loose coupling reduced to only 8.2% difference by applying sequential coupling in the case studied. Therefore, in order to reach more accurate predictions, applying sequential coupling especially at higher discharge voltages is strongly recommended.

  9. Waves in strong centrifugal fields: dissipationless gas

    Science.gov (United States)

    Bogovalov, S. V.; Kislov, V. A.; Tronin, I. V.

    2015-04-01

    Linear waves are investigated in a rotating gas under the condition of strong centrifugal acceleration of the order 106 g realized in gas centrifuges for separation of uranium isotopes. Sound waves split into three families of the waves under these conditions. Dispersion equations are obtained. The characteristics of the waves strongly differ from the conventional sound waves on polarization, velocity of propagation and distribution of energy of the waves in space for two families having frequencies above and below the frequency of the conventional sound waves. The energy of these waves is localized in rarefied region of the gas. The waves of the third family were not specified before. They propagate exactly along the rotational axis with the conventional sound velocity. These waves are polarized only along the rotational axis. Radial and azimuthal motions are not excited. Energy of the waves is concentrated near the wall of the rotor where the density of the gas is largest.

  10. FDTD simulation of trapping nanowires with linearly polarized and radially polarized optical tweezers.

    Science.gov (United States)

    Li, Jing; Wu, Xiaoping

    2011-10-10

    In this paper a model of the trapping force on nanowires is built by three dimensional finite-difference time-domain (FDTD) and Maxwell stress tensor methods, and the tightly focused laser beam is expressed by spherical vector wave functions (VSWFs). The trapping capacities on nanoscale-diameter nanowires are discussed in terms of a strongly focused linearly polarized beam and radially polarized beam. Simulation results demonstrate that the radially polarized beam has higher trapping efficiency on nanowires with higher refractive indices than linearly polarized beam.

  11. Strong intrinsic motivation

    OpenAIRE

    Dessi, Roberta; Rustichini, Aldo

    2015-01-01

    A large literature in psychology, and more recently in economics, has argued that monetary rewards can reduce intrinsic motivation. We investigate whether the negative impact persists when intrinsic motivation is strong, and test this hypothesis experimentally focusing on the motivation to undertake interesting and challenging tasks, informative about individual ability. We find that this type of task can generate strong intrinsic motivation, that is impervious to the effect of monetary incen...

  12. Bitcoin Meets Strong Consistency

    OpenAIRE

    Decker, Christian; Seidel, Jochen; Wattenhofer, Roger

    2014-01-01

    The Bitcoin system only provides eventual consistency. For everyday life, the time to confirm a Bitcoin transaction is prohibitively slow. In this paper we propose a new system, built on the Bitcoin blockchain, which enables strong consistency. Our system, PeerCensus, acts as a certification authority, manages peer identities in a peer-to-peer network, and ultimately enhances Bitcoin and similar systems with strong consistency. Our extensive analysis shows that PeerCensus is in a secure state...

  13. Strong gravity and supersymmetry

    International Nuclear Information System (INIS)

    Chamseddine, Ali H.; Salam, A.; Strathdee, J.

    1977-11-01

    A supersymmetric theory is constructed for a strong f plus a weak g graviton, together with their accompanying massive gravitinos, by gaugin the gradel 0Sp(2,2,1)x 0Sp(2,2,1) structure. The mixing term between f and g fields, which makes the strong graviton massive, can be introduced through a spontaneous symmetry-breaking mechanism implemented in this note by constructing a non-linear realization of the symmetry group

  14. Levitated superconductor ring trap (mini-RT) project - A new self-organized structure with strong plasma flow

    International Nuclear Information System (INIS)

    Ogawa, Y.; Himura, H.; Hishinuma, Y.

    2003-01-01

    Mahajan-Yoshida has theoretically developed a new relaxation state under the condition of a strong plasma flow, and proposed a possibility for confining high beta plasmas. In this self-organized state, two fluids (electron and ion) would relax to the condition given by the relation β + (V/V A ) 2 = const.. An internal coil device is suitable for studying a self-organized structure with strong plasma flow, because a strong toroidal flow is easily induced by introducing an appropriate radial electric field. We are constructing a Mini-RT device, which is equipping a floating coil with a high temperature superconductor (HTS) coil (R=0.15m, Ic=50kAturns). The magnetic field strength near the floating coil is around 0.1 T, and the plasma production with 2.45 GHz Electron Cyclotron Heating is planned. We are preparing several techniques to build up the radial electric field in the plasma such as the direct insertion of the electrode and so on. The utilization of direct orbit loss of high energy electrons produced by ECH might be an interesting method. The orbit calculation results show that the electrons with the energy of more than 10 keV would escape at the outer region of the plasma column, yielding the build-up of the radial electric field. The engineering aspect of the HTS coil is in progress. We have fabricated a small HTS coil (R=0.04 m and Ic= 2.6 kAturns), and succeeded in levitating it during four minutes with an accuracy of a few tens of micrometers. Since the HTS coil is excited by the external power supply, the persistent current switch for the HTS coil has been developed. The HTS coil system with the PCS coil has been fabricated and the excitation test has been carried out. We have succeeded in achieving a persistent current, and it is found that the decay constant of the coil current is evaluated to be around 40 hours and 6.5 hours at 20 K and 40 K, respectively. (author)

  15. WWER radial reflector modeling by diffusion codes

    International Nuclear Information System (INIS)

    Petkov, P. T.; Mittag, S.

    2005-01-01

    The two commonly used approaches to describe the WWER radial reflectors in diffusion codes, by albedo on the core-reflector boundary and by a ring of diffusive assembly size nodes, are discussed. The advantages and disadvantages of the first approach are presented first, then the Koebke's equivalence theory is outlined and its implementation for the WWER radial reflectors is discussed. Results for the WWER-1000 reactor are presented. Then the boundary conditions on the outer reflector boundary are discussed. The possibility to divide the library into fuel assembly and reflector parts and to generate each library by a separate code package is discussed. Finally, the homogenization errors for rodded assemblies are presented and discussed (Author)

  16. Oculoauriculovertebral spectrum with radial anomaly in child.

    Science.gov (United States)

    Taksande, Amar; Vilhekar, Krishna

    2013-01-01

    Oculoauriculovertebral spectrum (OAVS) or Goldenhar syndrome is a wide spectrum of congenital anomalies that involves structures arising from the first and second branchial arches. It is characterized by a wide spectrum of symptoms and physical features. These abnormalities mainly involve the cheekbones, jaws, mouth, ears, eyes, or vertebrae. Other conditions with ear and/or radial involvement, such as, the Nager syndrome, Holt-Oram syndrome, Radial-renal syndrome, facioauriculoradial dysplasia, Fanconi anemia, and Vertebral, Anal atresia, Cardiac, Trachea, Esophageal, Renal, and Limb (VACTERL) association should be considered for differential diagnosis. Here we report a child who had facial asymmetry, microsomia, microtia, congenital facial nerve palsy, conductive hearing loss, skin tags, iris coloboma, and preaxial polydactyly.

  17. Oculoauriculovertebral spectrum with radial anomaly in child

    Directory of Open Access Journals (Sweden)

    Amar Taksande

    2013-01-01

    Full Text Available Oculoauriculovertebral spectrum (OAVS or Goldenhar syndrome is a wide spectrum of congenital anomalies that involves structures arising from the first and second branchial arches. It is characterized by a wide spectrum of symptoms and physical features. These abnormalities mainly involve the cheekbones, jaws, mouth, ears, eyes, or vertebrae. Other conditions with ear and/or radial involvement, such as, the Nager syndrome, Holt-Oram syndrome, Radial-renal syndrome, facioauriculoradial dysplasia, Fanconi anemia, and Vertebral, Anal atresia, Cardiac, Trachea, Esophageal, Renal, and Limb (VACTERL association should be considered for differential diagnosis. Here we report a child who had facial asymmetry, microsomia, microtia, congenital facial nerve palsy, conductive hearing loss, skin tags, iris coloboma, and preaxial polydactyly.

  18. Linear radial pulsation theory. Lecture 5

    International Nuclear Information System (INIS)

    Cox, A.N.

    1983-01-01

    We describe a method for getting an equilibrium stellar envelope model using as input the total mass, the envelope mass, the surface effective temperature, the total surface luminosity, and the composition of the envelope. Then wih the structure of the envelope model known, we present a method for obtaining the raidal pulsation periods and growth rates for low order modes. The large amplitude pulsations observed for the yellow and red giants and supergiants are always these radial models, but for the stars nearer the main sequence, as for all of our stars and for the white dwarfs, there frequently are nonradial modes occuring also. Application of linear theory radial pulsation theory is made to the giant star sigma Scuti variables, while the linear nonradial theory will be used for the B stars in later lectures

  19. SpicyNodes Radial Map Engine

    Science.gov (United States)

    Douma, M.; Ligierko, G.; Angelov, I.

    2008-10-01

    The need for information has increased exponentially over the past decades. The current systems for constructing, exploring, classifying, organizing, and searching information face the growing challenge of enabling their users to operate efficiently and intuitively in knowledge-heavy environments. This paper presents SpicyNodes, an advanced user interface for difficult interaction contexts. It is based on an underlying structure known as a radial map, which allows users to manipulate and interact in a natural manner with entities called nodes. This technology overcomes certain limitations of existing solutions and solves the problem of browsing complex sets of linked information. SpicyNodes is also an organic system that projects users into a living space, stimulating exploratory behavior and fostering creative thought. Our interactive radial layout is used for educational purposes and has the potential for numerous other applications.

  20. Stability of a radial immiscible drive

    Energy Technology Data Exchange (ETDEWEB)

    Bataille, J

    1968-11-01

    The stability of the displacement front between 2 immiscible fluids of radial flow between 2 parallel plates (Hele-Shaw model) is studied mathematically by superposing onto the circular displacement front a sinusoidal perturbation. The equations are reduced to dimensionless variables, and it is shown that the stable and unstable domains in a plot: dimensionless viscosity vs. dimensionless time are separated by a polygonal contour, each side of the contour being characterized by the (integer) number of perturbations along the circumference. There is a critical reduced time below which the perturbations are amortized but beyond which they are amplified. Experimental results have been in fair general agreement with theoretical results, the divergence between them being attributable to neglecting capillary phenomena, which may become very important at large radial distances. One test with miscible fluids has shown that even in this case, there is a critical time or an equivalent critical radius.

  1. Radial magnetic compression in the expelled jet of a plasma deflagration accelerator

    International Nuclear Information System (INIS)

    Loebner, Keith T. K.; Underwood, Thomas C.; Mouratidis, Theodore; Cappelli, Mark A.

    2016-01-01

    A spectroscopic study of a pulsed plasma deflagration accelerator is carried out that confirms the existence of a strong compression in the emerging jet at the exit plane of the device. An imaging spectrometer is used to collect broadened Hα emission from a transaxial slice of the emerging jet at high spatial resolution, and the radial plasma density profile is computed from Voigt fits of the Abel inverted emissivity profiles. The plasma temperature, determined via Doppler broadening of impurity line emission, is compared against the temperature predictions of a radial magnetohydrodynamic equilibrium model applied to the measured density profiles. Empirical scaling laws developed for the plasma density, combined with the measured and predicted temperatures, indicate that a radially equilibrated Z-pinch is formed within the expelled plasma jet at the exit plane during the deflagration process.

  2. Radial oxygen gradients over rat cortex arterioles

    OpenAIRE

    Galler, Michael

    2011-01-01

    Purpose: We present the results of the visualisation of radial oxygen gradients in rats’ cortices and their use in neurocritical management. Methods: PO2 maps of the cortex of 10 wistar rats were obtained with a camera (SensiMOD, PCO, Kehlheim, Germany). Those pictures were analyzed and edited by a custom-made software. We chose a vessel for examination. A matrix, designed to evaluate the cortical O2 partial pressure, was placed vertically to the artery and afterwards multiple regio...

  3. Variational method for integrating radial gradient field

    Science.gov (United States)

    Legarda-Saenz, Ricardo; Brito-Loeza, Carlos; Rivera, Mariano; Espinosa-Romero, Arturo

    2014-12-01

    We propose a variational method for integrating information obtained from circular fringe pattern. The proposed method is a suitable choice for objects with radial symmetry. First, we analyze the information contained in the fringe pattern captured by the experimental setup and then move to formulate the problem of recovering the wavefront using techniques from calculus of variations. The performance of the method is demonstrated by numerical experiments with both synthetic and real data.

  4. Moment approach to tandem mirror radial transport

    International Nuclear Information System (INIS)

    Siebert, K.D.; Callen, J.D.

    1986-02-01

    A moment approach is proposed for the study of tandem mirror radial transport in the resonant plateau regime. The salient features of the method are described with reference to axisymmetric tokamak transport theory. In particular, the importance of momentum conservation to the establishment of the azimuthal variations in the electrostatic potential is demonstrated. Also, an ad hoc drift kinetic equation is solved to determine parallel viscosity coefficients which are required to close the moment system

  5. Numerical simulation of radial compressor stage

    Science.gov (United States)

    Syka, T.; Luňáček, O.

    2013-04-01

    Article describes numerical simulations of air flow in radial compressor stage in NUMECA CFD software. In simulations geometry variants with and without seals are used. During tasks evaluating was observed seals influence on flow field and performance parameters of compressor stage. Also is described CFDresults comparison with results from design software based on experimental measurements and monitoring of influence of seals construction on compressor stage efficiency.

  6. Numerical simulation of radial compressor stage

    OpenAIRE

    Luňáček O.; Syka T.

    2013-01-01

    Article describes numerical simulations of air flow in radial compressor stage in NUMECA CFD software. In simulations geometry variants with and without seals are used. During tasks evaluating was observed seals influence on flow field and performance parameters of compressor stage. Also is described CFDresults comparison with results from design software based on experimental measurements and monitoring of influence of seals construction on compressor stage efficiency.

  7. Numerical simulation of radial compressor stage

    Directory of Open Access Journals (Sweden)

    Luňáček O.

    2013-04-01

    Full Text Available Article describes numerical simulations of air flow in radial compressor stage in NUMECA CFD software. In simulations geometry variants with and without seals are used. During tasks evaluating was observed seals influence on flow field and performance parameters of compressor stage. Also is described CFDresults comparison with results from design software based on experimental measurements and monitoring of influence of seals construction on compressor stage efficiency.

  8. Radial excitations in nucleon-nucleon scattering

    International Nuclear Information System (INIS)

    Silvestre-Brac, B.; Carbonell, J.; Gignoux, C.

    1986-01-01

    In the non-relativistic constituent quark model, the role of the radial excitations of the nucleon is studied within a resonating group approach of the nucleon-nucleon scattering. It is shown that, rather than the inclusion of new channels, it is important to include mixed-symmetry spin-isospin components in the nucleon wave function. It is also found that during the collision there is no significant deformation of the nucleon. (orig.)

  9. Learning Methods for Radial Basis Functions Networks

    Czech Academy of Sciences Publication Activity Database

    Neruda, Roman; Kudová, Petra

    2005-01-01

    Roč. 21, - (2005), s. 1131-1142 ISSN 0167-739X R&D Projects: GA ČR GP201/03/P163; GA ČR GA201/02/0428 Institutional research plan: CEZ:AV0Z10300504 Keywords : radial basis function networks * hybrid supervised learning * genetic algorithms * benchmarking Subject RIV: BA - General Mathematics Impact factor: 0.555, year: 2005

  10. Fast radial basis functions for engineering applications

    CERN Document Server

    Biancolini, Marco Evangelos

    2017-01-01

    This book presents the first “How To” guide to the use of radial basis functions (RBF). It provides a clear vision of their potential, an overview of ready-for-use computational tools and precise guidelines to implement new engineering applications of RBF. Radial basis functions (RBF) are a mathematical tool mature enough for useful engineering applications. Their mathematical foundation is well established and the tool has proven to be effective in many fields, as the mathematical framework can be adapted in several ways. A candidate application can be faced considering the features of RBF:  multidimensional space (including 2D and 3D), numerous radial functions available, global and compact support, interpolation/regression. This great flexibility makes RBF attractive – and their great potential has only been partially discovered. This is because of the difficulty in taking a first step toward RBF as they are not commonly part of engineers’ cultural background, but also due to the numerical complex...

  11. Development of a Radial Deconsolidation Method

    Energy Technology Data Exchange (ETDEWEB)

    Helmreich, Grant W. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Montgomery, Fred C. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Hunn, John D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-12-01

    A series of experiments have been initiated to determine the retention or mobility of fission products* in AGR fuel compacts [Petti, et al. 2010]. This information is needed to refine fission product transport models. The AGR-3/4 irradiation test involved half-inch-long compacts that each contained twenty designed-to-fail (DTF) particles, with 20-μm thick carbon-coated kernels whose coatings were deliberately fabricated such that they would crack under irradiation, providing a known source of post-irradiation isotopes. The DTF particles in these compacts were axially distributed along the compact centerline so that the diffusion of fission products released from the DTF kernels would be radially symmetric [Hunn, et al. 2012; Hunn et al. 2011; Kercher, et al. 2011; Hunn, et al. 2007]. Compacts containing DTF particles were irradiated at Idaho National Laboratory (INL) at the Advanced Test Reactor (ATR) [Collin, 2015]. Analysis of the diffusion of these various post-irradiation isotopes through the compact requires a method to radially deconsolidate the compacts so that nested-annular volumes may be analyzed for post-irradiation isotope inventory in the compact matrix, TRISO outer pyrolytic carbon (OPyC), and DTF kernels. An effective radial deconsolidation method and apparatus appropriate to this application has been developed and parametrically characterized.

  12. Tire-rim interface pressure of a commercial vehicle wheel under radial loads: theory and experiment

    Science.gov (United States)

    Wan, Xiaofei; Shan, Yingchun; Liu, Xiandong; He, Tian; Wang, Jiegong

    2017-11-01

    The simulation of the radial fatigue test of a wheel has been a necessary tool to improve the design of the wheel and calculate its fatigue life. The simulation model, including the strong nonlinearity of the tire structure and material, may produce accurate results, but often leads to a divergence in calculation. Thus, a simplified simulation model in which the complicated tire model is replaced with a tire-wheel contact pressure model is used extensively in the industry. In this paper, a simplified tire-rim interface pressure model of a wheel under a radial load is established, and the pressure of the wheel under different radial loads is tested. The tire-rim contact behavior affected by the radial load is studied and analyzed according to the test result, and the tire-rim interface pressure extracted from the test result is used to evaluate the simplified pressure model and the traditional cosine function model. The results show that the proposed model may provide a more accurate prediction of the wheel radial fatigue life than the traditional cosine function model.

  13. Radial transport in the Elmo Bumpy Torus in collisionless electron regimes

    International Nuclear Information System (INIS)

    Jaeger, E.F.; Hedrick, C.L.; Spong, D.A.

    1979-01-01

    One important area of disagreement between radial transport theory and the ELMO Bumpy Torus (EBT) experiment has been the degree of collisionality of the toroidal plasma electrons. Experiment shows relatively warm electrons (kTsub(e) approximately 300-600eV) and collisionless scaling, i.e. energy confinement increasing with temperature. But results of early one-dimensional (1-D), neoclassical transport models with radially inward pointing electric fields are limited to relatively cool electrons (kTsub(e) approximately 100-200eV) and collisional scaling. In this paper these early results are extended to include lowest-order effects of ion diffusion in regions where poloidal drift frequencies are small. The effects of direct, or non-diffusive, losses in such regions are neglected along with the effects of finite radial electric fields on electron transport coefficients and of self-consistent poloidal electric fields on ion transport coefficients. Results show that solutions in the collisionless electron regime do exist. Furthermore, when the effects of finite electron ring beta on magnetic fields near the plasma edge are included, these solutions occur at power levels consistent with experiment. (author)

  14. Strongly interacting Fermi gases

    Directory of Open Access Journals (Sweden)

    Bakr W.

    2013-08-01

    Full Text Available Strongly interacting gases of ultracold fermions have become an amazingly rich test-bed for many-body theories of fermionic matter. Here we present our recent experiments on these systems. Firstly, we discuss high-precision measurements on the thermodynamics of a strongly interacting Fermi gas across the superfluid transition. The onset of superfluidity is directly observed in the compressibility, the chemical potential, the entropy, and the heat capacity. Our measurements provide benchmarks for current many-body theories on strongly interacting fermions. Secondly, we have studied the evolution of fermion pairing from three to two dimensions in these gases, relating to the physics of layered superconductors. In the presence of p-wave interactions, Fermi gases are predicted to display toplogical superfluidity carrying Majorana edge states. Two possible avenues in this direction are discussed, our creation and direct observation of spin-orbit coupling in Fermi gases and the creation of fermionic molecules of 23Na 40K that will feature strong dipolar interactions in their absolute ground state.

  15. A strong comeback

    International Nuclear Information System (INIS)

    Marier, D.

    1992-01-01

    This article presents the results of a financial rankings survey which show a strong economic activity in the independent energy industry. The topics of the article include advisor turnover, overseas banks, and the increase in public offerings. The article identifies the top project finance investors for new projects and restructurings and rankings for lenders

  16. Linear theory radial and nonradial pulsations of DA dwarf stars

    International Nuclear Information System (INIS)

    Starrfield, S.; Cox, A.N.; Hodson, S.; Pesnell, W.D.

    1982-01-01

    The Los Alamos stellar envelope and radial linear non-adiabatic computer code, along with a new Los Alamos non-radial code are used to investigate the total hydrogen mass necessary to produce the non-radial instability of DA dwarfs

  17. Radial distribution of ions in pores with a surface charge

    NARCIS (Netherlands)

    Stegen, J.H.G. van der; Görtzen, J.; Kuipers, J.A.M.; Hogendoorn, J.A.; Versteeg, G.F.

    2001-01-01

    A sorption model applicable to calculate the radial equilibrium concentrations of ions in the pores of ion-selective membranes with a pore structure is developed. The model is called the radial uptake model. Because the model is applied to a Nafion sulfonic layer with very small pores and the radial

  18. Experimental feasibility study of radial injection cooling of three-pad radial air foil bearings

    Science.gov (United States)

    Shrestha, Suman K.

    Air foil bearings use ambient air as a lubricant allowing environment-friendly operation. When they are designed, installed, and operated properly, air foil bearings are very cost effective and reliable solution to oil-free turbomachinery. Because air is used as a lubricant, there are no mechanical contacts between the rotor and bearings and when the rotor is lifted off the bearing, near frictionless quiet operation is possible. However, due to the high speed operation, thermal management is one of the very important design factors to consider. Most widely accepted practice of the cooling method is axial cooling, which uses cooling air passing through heat exchange channels formed underneath the bearing pad. Advantage is no hardware modification to implement the axial cooling because elastic foundation structure of foil bearing serves as a heat exchange channels. Disadvantage is axial temperature gradient on the journal shaft and bearing. This work presents the experimental feasibility study of alternative cooling method using radial injection of cooling air directly on the rotor shaft. The injection speeds, number of nozzles, location of nozzles, total air flow rate are important factors determining the effectiveness of the radial injection cooling method. Effectiveness of the radial injection cooling was compared with traditional axial cooling method. A previously constructed test rig was modified to accommodate a new motor with higher torque and radial injection cooling. The radial injection cooling utilizes the direct air injection to the inlet region of air film from three locations at 120° from one another with each location having three axially separated holes. In axial cooling, a certain axial pressure gradient is applied across the bearing to induce axial cooling air through bump foil channels. For the comparison of the two methods, the same amount of cooling air flow rate was used for both axial cooling and radial injection. Cooling air flow rate was

  19. Behavior of highly diluted electrolytes in strong electric fields-prevention of alumina deposition on grading electrodes in HVDC transmission modules by CO2-induced pH-control.

    Science.gov (United States)

    Weber, Immo; Mallick, Bert; Schild, Matthias; Kareth, Sabine; Puchta, Ralph; van Eldik, Rudi

    2014-09-15

    Alumina deposition on platinum grading electrodes in high voltage direct current (HVDC) transmission modules is an unsolved problem that has been around for more than three decades. This is due to the unavoidable corrosion of aluminum heat sinks that causes severe damage to electrical power plants and losses in the range of a million Euro range per day in power outage. Simple experiments in a representative HV test setup showed that aluminates at concentrations even below 10(-8) mol L(-1) can deposit on anodes through neutralization by protons produced in de-ionized water (κ≤0.15 μS cm(-1)) at 20-35 kV (8 mA) per electrode. In this otherwise electrolyte-poor aqueous environment, the depositions are formed three orders of magnitude below the critical precipitation concentration at pH 7! In the presence of an inert electrolyte such as TMAT (tetramethylammonium-p-toluenesulfonate), at a concentration level just above that of the total dissolved aluminum, no deposition was observed. Deposition can be also prevented by doping with CO2 gas at a concentration level that is magnitudes lower than that of the dissolved aluminum. From an overview of aqueous aluminum chemistry, the mystery of the alumina deposition process and its inhibition by CO2 is experimentally resolved and fully explained by field accumulation and repulsion models in synergism with acid-base equilibria. The extraordinary size of the alumina depositions is accounted for in terms of proton tunneling through "hydrated" alumina, which is supported by quantum chemical calculations. As a consequence, pulse-purging with pure CO2 gas is presented as a technical solution to prevent the deposition of alumina. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Strong Electroweak Symmetry Breaking

    CERN Document Server

    Grinstein, Benjamin

    2011-01-01

    Models of spontaneous breaking of electroweak symmetry by a strong interaction do not have fine tuning/hierarchy problem. They are conceptually elegant and use the only mechanism of spontaneous breaking of a gauge symmetry that is known to occur in nature. The simplest model, minimal technicolor with extended technicolor interactions, is appealing because one can calculate by scaling up from QCD. But it is ruled out on many counts: inappropriately low quark and lepton masses (or excessive FCNC), bad electroweak data fits, light scalar and vector states, etc. However, nature may not choose the minimal model and then we are stuck: except possibly through lattice simulations, we are unable to compute and test the models. In the LHC era it therefore makes sense to abandon specific models (of strong EW breaking) and concentrate on generic features that may indicate discovery. The Technicolor Straw Man is not a model but a parametrized search strategy inspired by a remarkable generic feature of walking technicolor,...

  1. Plasmons in strong superconductors

    International Nuclear Information System (INIS)

    Baldo, M.; Ducoin, C.

    2011-01-01

    We present a study of the possible plasmon excitations that can occur in systems where strong superconductivity is present. In these systems the plasmon energy is comparable to or smaller than the pairing gap. As a prototype of these systems we consider the proton component of Neutron Star matter just below the crust when electron screening is not taken into account. For the realistic case we consider in detail the different aspects of the elementary excitations when the proton, electron components are considered within the Random-Phase Approximation generalized to the superfluid case, while the influence of the neutron component is considered only at qualitative level. Electron screening plays a major role in modifying the proton spectrum and spectral function. At the same time the electron plasmon is strongly modified and damped by the indirect coupling with the superfluid proton component, even at moderately low values of the gap. The excitation spectrum shows the interplay of the different components and their relevance for each excitation modes. The results are relevant for neutrino physics and thermodynamical processes in neutron stars. If electron screening is neglected, the spectral properties of the proton component show some resemblance with the physical situation in high-T c superconductors, and we briefly discuss similarities and differences in this connection. In a general prospect, the results of the study emphasize the role of Coulomb interaction in strong superconductors.

  2. Methods and apparatus for radially compliant component mounting

    Science.gov (United States)

    Bulman, David Edward [Cincinnati, OH; Darkins, Jr., Toby George; Stumpf, James Anthony [Columbus, IN; Schroder, Mark S [Greenville, SC; Lipinski, John Joseph [Simpsonville, SC

    2012-03-27

    Methods and apparatus for a mounting assembly for a liner of a gas turbine engine combustor are provided. The combustor includes a combustor liner and a radially outer annular flow sleeve. The mounting assembly includes an inner ring surrounding a radially outer surface of the liner and including a plurality of axially extending fingers. The mounting assembly also includes a radially outer ring coupled to the inner ring through a plurality of spacers that extend radially from a radially outer surface of the inner ring to the outer ring.

  3. Radial fractional Laplace operators and Hessian inequalities

    Science.gov (United States)

    Ferrari, Fausto; Verbitsky, Igor E.

    In this paper we deduce a formula for the fractional Laplace operator ( on radially symmetric functions useful for some applications. We give a criterion of subharmonicity associated with (, and apply it to a problem related to the Hessian inequality of Sobolev type: ∫Rn |(u| dx⩽C∫Rn -uFk[u] dx, where Fk is the k-Hessian operator on Rn, 1⩽kFerrari et al. [5] contains the extremal functions for the Hessian Sobolev inequality of X.-J. Wang (1994) [15]. This is proved using logarithmic convexity of the Gaussian ratio of hypergeometric functions which might be of independent interest.

  4. Convex and Radially Concave Contoured Distributions

    Directory of Open Access Journals (Sweden)

    Wolf-Dieter Richter

    2015-01-01

    Full Text Available Integral representations of the locally defined star-generalized surface content measures on star spheres are derived for boundary spheres of balls being convex or radially concave with respect to a fan in Rn. As a result, the general geometric measure representation of star-shaped probability distributions and the general stochastic representation of the corresponding random vectors allow additional specific interpretations in the two mentioned cases. Applications to estimating and testing hypotheses on scaling parameters are presented, and two-dimensional sample clouds are simulated.

  5. On radial flow between parallel disks

    International Nuclear Information System (INIS)

    Wee, A Y L; Gorin, A

    2015-01-01

    Approximate analytical solutions are presented for converging flow in between two parallel non rotating disks. The static pressure distribution and radial component of the velocity are developed by averaging the inertial term across the gap in between parallel disks. The predicted results from the first approximation are favourable to experimental results as well as results presented by other authors. The second approximation shows that as the fluid approaches the center, the velocity at the mid channel slows down which is due to the struggle between the inertial term and the flowrate. (paper)

  6. Intraluminal milrinone for dilation of the radial artery graft.

    Science.gov (United States)

    García-Rinaldi, R; Soltero, E R; Carballido, J; Mojica, J

    1999-01-01

    There is renewed interest in the use of the radial artery as a conduit for coronary artery bypass surgery. The radial artery is, however, a very muscular artery, prone to vasospasm. Milrinone, a potent vasodilator, has demonstrated vasodilatory properties superior to those of papaverine. In this report, we describe our technique of radial artery harvesting and the adjunctive use of intraluminal milrinone as a vasodilator in the preparation of this conduit for coronary artery bypass grafting. We have used these techniques in 25 patients who have undergone coronary artery bypass grafting using the radial artery. No hand ischemic complications have been observed in this group. Intraluminal milrinone appears to dilate and relax the radial artery, rendering this large conduit spasm free and very easy to use. We recommend the skeletonization technique for radial artery harvesting and the use of intraluminal milrinone as a radial artery vasodilator in routine myocardial revascularization. PMID:10524740

  7. Strongly intensive quantities

    International Nuclear Information System (INIS)

    Gorenstein, M. I.; Gazdzicki, M.

    2011-01-01

    Analysis of fluctuations of hadron production properties in collisions of relativistic particles profits from use of measurable intensive quantities which are independent of system size variations. The first family of such quantities was proposed in 1992; another is introduced in this paper. Furthermore we present a proof of independence of volume fluctuations for quantities from both families within the framework of the grand canonical ensemble. These quantities are referred to as strongly intensive ones. Influence of conservation laws and resonance decays is also discussed.

  8. Strong-coupling approximations

    International Nuclear Information System (INIS)

    Abbott, R.B.

    1984-03-01

    Standard path-integral techniques such as instanton calculations give good answers for weak-coupling problems, but become unreliable for strong-coupling. Here we consider a method of replacing the original potential by a suitably chosen harmonic oscillator potential. Physically this is motivated by the fact that potential barriers below the level of the ground-state energy of a quantum-mechanical system have little effect. Numerically, results are good, both for quantum-mechanical problems and for massive phi 4 field theory in 1 + 1 dimensions. 9 references, 6 figures

  9. Optimal siting of capacitors in radial distribution network using Whale Optimization Algorithm

    Directory of Open Access Journals (Sweden)

    D.B. Prakash

    2017-12-01

    Full Text Available In present days, continuous effort is being made in bringing down the line losses of the electrical distribution networks. Therefore proper allocation of capacitors is of utmost importance because, it will help in reducing the line losses and maintaining the bus voltage. This in turn results in improving the stability and reliability of the system. In this paper Whale Optimization Algorithm (WOA is used to find optimal sizing and placement of capacitors for a typical radial distribution system. Multi objectives such as operating cost reduction and power loss minimization with inequality constraints on voltage limits are considered and the proposed algorithm is validated by applying it on standard radial systems: IEEE-34 bus and IEEE-85 bus radial distribution test systems. The results obtained are compared with those of existing algorithms. The results show that the proposed algorithm is more effective in bringing down the operating costs and in maintaining better voltage profile. Keywords: Whale Optimization Algorithm (WOA, Optimal allocation and sizing of capacitors, Power loss reduction and voltage stability improvement, Radial distribution system, Operating cost minimization

  10. Channeling potential in single-walled carbon nanotubes: The effect of radial deformation

    International Nuclear Information System (INIS)

    Abu-Assy, M.K.; Soliman, M.S.

    2016-01-01

    We study the effect of radial deformation in single-walled carbon nanotubes (SWCNTs), due to one external factor, on the channeling potential. The calculations covered the channeling potential for positrons of 100 MeV move along the z-axis, which is the axis of the radially deformed SWCNTs (6, 0), (8, 0) under external mechanical stress at different values for the induced strain and also for radially deformed SWCNT (5, 5) under external transverse electric field of 1.8 and 2.6 V/Å. The calculations executed according to the continuum model approximation given by Lindhard for the case of an axial channeling in single crystals. The results of the calculations in this work agreed well with previous calculations depending on the equilibrium electron density in perfect carbon nanotubes. It has been found that, for perfect nanotubes, the channeling potential, i.e., the potential at any point (x, y) in a plane normal to the nanotube axis (xy-plane), is a function of the distance from the nanotube center whatever the (x, y) coordinate and hence, it could be expressed in terms of one independent variable. On the other hand, in radially deformed SWCNTs, the channeling potential was found to be a function of two independent variables (x, y) and could be given here by a general formula in terms of fitting parameters for each nanotube with chiral index (n, m). The obtained formula has been used in plotting the contour plot for the channeling potential.

  11. Characterization of the loss allocation techniques for radial systems with distributed generation

    International Nuclear Information System (INIS)

    Carpaneto, Enrico; Chicco, Gianfranco; Sumaili Akilimali, Jean

    2008-01-01

    In the restructured electricity industry, meaningful loss allocation methods are required in order to send correct signals to the market taking into account the location and characteristics of loads and generations, including the local sources forming the distributed generation (DG). This paper addresses the issues related to loss allocation in radial distribution systems with DG, with a three-fold focus. First, the key differences in the formulation of the loss allocation problem for radial distribution systems with respect to transmission systems are discussed, specifying the modeling and computational issues concerning the treatment of the slack node in radial distribution systems. Then, the characteristics of derivative-based and circuit-based loss allocation techniques are presented and compared, illustrating the arrangements used for adapting the various techniques to be applied to radial distribution systems with DG. Finally, the effects of introducing voltage-controllable local generation on the calculation of the loss allocation coefficients are discussed, proposing the adoption of a ''reduced'' representation of the system capable of taking into proper account the characteristics of the nodes containing voltage-controllable DG units. Numerical results are provided to show the time evolution of the loss allocation coefficients for distribution systems with variable load and local generation patterns. (author)

  12. Channeling potential in single-walled carbon nanotubes: The effect of radial deformation

    Energy Technology Data Exchange (ETDEWEB)

    Abu-Assy, M.K. [Physics Department, Faculty of Science, Suez-Canal University, Ismailia 41522 (Egypt); Soliman, M.S., E-mail: Mahmoud_einstien2@yahoo.com [Physics Department, Faculty of Science, Suez-Canal University, El-Arish (Egypt)

    2016-10-01

    We study the effect of radial deformation in single-walled carbon nanotubes (SWCNTs), due to one external factor, on the channeling potential. The calculations covered the channeling potential for positrons of 100 MeV move along the z-axis, which is the axis of the radially deformed SWCNTs (6, 0), (8, 0) under external mechanical stress at different values for the induced strain and also for radially deformed SWCNT (5, 5) under external transverse electric field of 1.8 and 2.6 V/Å. The calculations executed according to the continuum model approximation given by Lindhard for the case of an axial channeling in single crystals. The results of the calculations in this work agreed well with previous calculations depending on the equilibrium electron density in perfect carbon nanotubes. It has been found that, for perfect nanotubes, the channeling potential, i.e., the potential at any point (x, y) in a plane normal to the nanotube axis (xy-plane), is a function of the distance from the nanotube center whatever the (x, y) coordinate and hence, it could be expressed in terms of one independent variable. On the other hand, in radially deformed SWCNTs, the channeling potential was found to be a function of two independent variables (x, y) and could be given here by a general formula in terms of fitting parameters for each nanotube with chiral index (n, m). The obtained formula has been used in plotting the contour plot for the channeling potential.

  13. Poloidal spin up and electric-field generation related to displacement current and neoclassical transport

    International Nuclear Information System (INIS)

    Gervasini, G.; Lazzaro, E.; Minardi, E.

    1996-01-01

    In accordance with the conventional ordering of neoclassical theory, poloidal and toroidal accelerations with constant parallel flow can be driven by heat transport in the absence of external momentum input and with vanishing parallel viscous stress. In a transient phase in which the heat transport is the primary source of the time dependence, the torque generating the rotation is provided at third order in the adiabatic expansion by the surface-averaged (non ambipolar) displacement current, which in also responsible for charge build-up and for the radial electric field. The heat transport equation has been solved in a narrow layer interfaced with the intensely heated plasma core through heat flux continuity, assuming neoclassical multi collisional coefficients with self-consistent suppression mechanism of anomalous transport. Starting from low temperature in the edge layer, a strong temperature gradient, a mass poloidal rotation in the ion direction and a strongly negative sheared radial electric field can be generated, in agreement with the observations, and reach a stationary state after a displacement current-dominated triggering phase (intrinsically non-ambipolar) lasting few milliseconds. Momentum input becomes important on longer time scale and is responsible for the toroidal rotation, decoupled from temperature gradient and for a further development of the radial electric field. The results show the ability of edge transport processes to adapt flexibly to a high temperature imposed on the inner side of the edge layer and support the view that the edge processes are a integral part of a more fundamental global process involving possibly an internal bifurcation of state

  14. Spherical radial basis functions, theory and applications

    CERN Document Server

    Hubbert, Simon; Morton, Tanya M

    2015-01-01

    This book is the first to be devoted to the theory and applications of spherical (radial) basis functions (SBFs), which is rapidly emerging as one of the most promising techniques for solving problems where approximations are needed on the surface of a sphere. The aim of the book is to provide enough theoretical and practical details for the reader to be able to implement the SBF methods to solve real world problems. The authors stress the close connection between the theory of SBFs and that of the more well-known family of radial basis functions (RBFs), which are well-established tools for solving approximation theory problems on more general domains. The unique solvability of the SBF interpolation method for data fitting problems is established and an in-depth investigation of its accuracy is provided. Two chapters are devoted to partial differential equations (PDEs). One deals with the practical implementation of an SBF-based solution to an elliptic PDE and another which describes an SBF approach for solvi...

  15. Asymptotic Solutions of Serial Radial Fuel Shuffling

    Directory of Open Access Journals (Sweden)

    Xue-Nong Chen

    2015-12-01

    Full Text Available In this paper, the mechanism of traveling wave reactors (TWRs is investigated from the mathematical physics point of view, in which a stationary fission wave is formed by radial fuel drifting. A two dimensional cylindrically symmetric core is considered and the fuel is assumed to drift radially according to a continuous fuel shuffling scheme. A one-group diffusion equation with burn-up dependent macroscopic coefficients is set up. The burn-up dependent macroscopic coefficients were assumed to be known as functions of neutron fluence. By introducing the effective multiplication factor keff, a nonlinear eigenvalue problem is formulated. The 1-D stationary cylindrical coordinate problem can be solved successively by analytical and numerical integrations for associated eigenvalues keff. Two representative 1-D examples are shown for inward and outward fuel drifting motions, respectively. The inward fuel drifting has a higher keff than the outward one. The 2-D eigenvalue problem has to be solved by a more complicated method, namely a pseudo time stepping iteration scheme. Its 2-D asymptotic solutions are obtained together with certain eigenvalues keff for several fuel inward drifting speeds. Distributions of the neutron flux, the neutron fluence, the infinity multiplication factor kinf and the normalized power are presented for two different drifting speeds.

  16. Strongly disordered superconductors

    International Nuclear Information System (INIS)

    Muttalib, K.A.

    1982-01-01

    We examine some universal effects of strong non-magnetic disorder on the electron-phonon and electron-electron interactions in a superconductor. In particular we explicitly take into account the effect of slow diffusion of electrons in a disordered medium by working in an exact impurity eigenstate representation. We find that the normal diffusion of electrons characterized by a constant diffusion coefficient does not lead to any significant correction to the electron-phonon or the effective electron-electron interactions in a superconductor. We then consider sufficiently strong disorder where Anderson localization of electrons becomes important and determine the effect of localization on the electron-electron interactions. We find that due to localization, the diffusion of electrons becomes anomalous in the sense that the diffusion coefficient becomes scale dependent. This results in an increase in the effective electron-electron interaction with increasing disorder. We propose that this provides a natural explanation for the unusual sensitivity of the transition temperature T/sub c/ of the high T/sub c/ superconductors (T/sub c/ > 10 0 K) to damage effects

  17. Strong Coupling Holography

    CERN Document Server

    Dvali, Gia

    2009-01-01

    We show that whenever a 4-dimensional theory with N particle species emerges as a consistent low energy description of a 3-brane embedded in an asymptotically-flat (4+d)-dimensional space, the holographic scale of high-dimensional gravity sets the strong coupling scale of the 4D theory. This connection persists in the limit in which gravity can be consistently decoupled. We demonstrate this effect for orbifold planes, as well as for the solitonic branes and string theoretic D-branes. In all cases the emergence of a 4D strong coupling scale from bulk holography is a persistent phenomenon. The effect turns out to be insensitive even to such extreme deformations of the brane action that seemingly shield 4D theory from the bulk gravity effects. A well understood example of such deformation is given by large 4D Einstein term in the 3-brane action, which is known to suppress the strength of 5D gravity at short distances and change the 5D Newton's law into the four-dimensional one. Nevertheless, we observe that the ...

  18. [Comparison of chemical quality characteristics between radial striations and non-radial striations in tuberous root of Rehmannia glutinosa].

    Science.gov (United States)

    Xie, Cai-Xia; Zhang, Miao; Li, Ya-Jing; Geng, Xiao-Tong; Wang, Feng-Qing; Zhang, Zhong-Yi

    2017-11-01

    An HPLC method was established to determine the contents of catalpol, acteoside, rehmaionoside A, rehmaionoside D, leonuride in three part of Rehmanni glutinosa in Beijing No.1 variety R. glutinosa during the growth period, This method, in combination with its HPLC fingerprint was used to evaluate its overall quality characteristics.The results showed that:① the content of main components of R. glutinosa varied in different growth stages ;② there was a great difference of the content of main components between theradial striations and the non-radial striations; ③ the two sections almost have the same content distribution of catalpol, acteoside and rehmaionoside D; ④the content of rehmaionoside A in non-radial striations was higher than that in radial striations,while the content of leonuride in radial striations was higher than that in non-radial striations.; ⑤the HPLC fingerprint of radial striations, non-radial striations and whole root tuber were basically identical, except for the big difference in the content of chemical components. The result of clustering displayed that the radial striations, non-radial striations, and whole root were divided into two groups. In conclusion, there was a significant difference in the quality characteristics of radial striations and non-radial striations of R. glutinosa. This research provides a reference for quality evaluation and geoherbalism of R. glutinosa. Copyright© by the Chinese Pharmaceutical Association.

  19. Strong Gravity Effects of Rotating Black Holes: Quasiperiodic Oscillations

    OpenAIRE

    Aliev, Alikram N.; Esmer, Göksel Daylan; Talazan, Pamir

    2012-01-01

    We explore strong gravity effects of the geodesic motion in the spacetime of rotating black holes in general relativity and braneworld gravity. We focus on the description of the motion in terms of three fundamental frequencies: The orbital frequency, the radial and vertical epicyclic frequencies. For a Kerr black hole, we perform a detailed numerical analysis of these frequencies at the innermost stable circular orbits and beyond them as well as at the characteristic stable orbits, at which ...

  20. Electric-magnetic duality in non-Abelian gauge theories

    International Nuclear Information System (INIS)

    Mizrachi, L.

    1982-03-01

    The duality transformation of the vacuum expectation value of the operator which creates magnetic vortices (the 't Hooft loop operator in the Higgs phase) is performed in the radial gauge (xsub(μ)Asub(μ)sup(a)(x)=0). It is found that in the weak coupling region (small g) of a pure Yang-Mills theory the dual operator creates electric vortices whose strength is 1/g. The theory is self dual in this region, and the effective coupling of the dual Lagrangian is 1/g. Thus the above duality transformation reduces to electric-magnetic duality where the electric field in the 't Hooft loop operator transforms into a magnetic field in the dual operator. In a spontaneously broken gauge theory these results are valid only within the region where the vortices (or the monopoles) are concentrated, or in directions of the algebra space of unbroken symmetry, as self duality holds only for this subset of fields. In the strong coupling region a strong coupling expansion in powers of 1/g is suggested. (author)

  1. LIGO: The strong belief

    CERN Multimedia

    Antonella Del Rosso

    2016-01-01

    Twenty years of designing, building and testing a number of innovative technologies, with the strong belief that the endeavour would lead to a historic breakthrough. The Bulletin publishes an abstract of the Courier’s interview with Barry Barish, one of the founding fathers of LIGO.   The plots show the signals of gravitational waves detected by the twin LIGO observatories at Livingston, Louisiana, and Hanford, Washington. (Image: Caltech/MIT/LIGO Lab) On 11 February, the Laser Interferometer Gravitational-Wave Observatory (LIGO) and Virgo collaborations published a historic paper in which they showed a gravitational signal emitted by the merger of two black holes. These results come after 20 years of hard work by a large collaboration of scientists operating the two LIGO observatories in the US. Barry Barish, Linde Professor of Physics, Emeritus at the California Institute of Technology and former Director of the Global Design Effort for the Internat...

  2. Strongly interacting Higgs bosons

    International Nuclear Information System (INIS)

    Appelquist, T.; Bernard, C.

    1980-01-01

    The sensitivity of present-energy weak interactions to a strongly interacting heavy-Higgs-boson sector is discussed. The gauged nonlinear sigma model, which is the limit of the linear model as the Higgs-boson mass goes to infinity, is used to organize and catalogue all possible heavy-Higgs-boson effects. As long as the SU(2)/sub L/ x SU(2)/sub R/ symmetry of the Higgs sector is preserved, these effects are found to be small, of the order of the square of the gauge coupling times logarithms (but not powers) of the Higgs-boson mass divided by the W mass. We work in the context of a simplified model with gauge group SU(2)/sub L/; the extension to SU(2)/sub L/ x U(1) is briefly discussed

  3. Computer model analysis of the radial artery pressure waveform.

    Science.gov (United States)

    Schwid, H A; Taylor, L A; Smith, N T

    1987-10-01

    Simultaneous measurements of aortic and radial artery pressures are reviewed, and a model of the cardiovascular system is presented. The model is based on resonant networks for the aorta and axillo-brachial-radial arterial system. The model chosen is a simple one, in order to make interpretation of the observed relationships clear. Despite its simplicity, the model produces realistic aortic and radial artery pressure waveforms. It demonstrates that the resonant properties of the arterial wall significantly alter the pressure waveform as it is propagated from the aorta to the radial artery. Although the mean and end-diastolic radial pressures are usually accurate estimates of the corresponding aortic pressures, the systolic pressure at the radial artery is often much higher than that of the aorta due to overshoot caused by the resonant behavior of the radial artery. The radial artery dicrotic notch is predominantly dependent on the axillo-brachial-radial arterial wall properties, rather than on the aortic valve or peripheral resistance. Hence the use of the radial artery dicrotic notch as an estimate of end systole is unreliable. The rate of systolic upstroke, dP/dt, of the radial artery waveform is a function of many factors, making it difficult to interpret. The radial artery waveform usually provides accurate estimates for mean and diastolic aortic pressures; for all other measurements it is an inadequate substitute for the aortic pressure waveform. In the presence of low forearm peripheral resistance the mean radial artery pressure may significantly underestimate the mean aortic pressure, as explained by a voltage divider model.

  4. Performance analysis of a new radial-axial flux machine with SMC cores and ferrite magnets

    Science.gov (United States)

    Liu, Chengcheng; Wang, Youhua; Lei, Gang; Guo, Youguang; Zhu, Jianguo

    2017-05-01

    Soft magnetic composite (SMC) is a popular material in designing of new 3D flux electrical machines nowadays for it has the merits of isotropic magnetic characteristic, low eddy current loss and high design flexibility over the electric steel. The axial flux machine (AFM) with the extended stator tooth tip both in the radial and circumferential direction is a good example, which has been investigated in the last years. Based on the 3D flux AFM and radial flux machine, this paper proposes a new radial-axial flux machine (RAFM) with SMC cores and ferrite magnets, which has very high torque density though the low cost low magnetic energy ferrite magnet is utilized. Moreover, the cost of RAFM is quite low since the manufacturing cost can be reduced by using the SMC cores and the material cost will be decreased due to the adoption of the ferrite magnets. The 3D finite element method (FEM) is used to calculate the magnetic flux density distribution and electromagnetic parameters. For the core loss calculation, the rotational core loss computation method is used based on the experiment results from previous 3D magnetic tester.

  5. Optoelectrical modeling of solar cells based on c-Si/a-Si:H nanowire array: focus on the electrical transport in between the nanowires

    Science.gov (United States)

    Levtchenko, Alexandra; Le Gall, Sylvain; Lachaume, Raphaël; Michallon, Jérôme; Collin, Stéphane; Alvarez, José; Djebbour, Zakaria; Kleider, Jean-Paul

    2018-06-01

    By coupling optical and electrical modeling, we have investigated the photovoltaic performances of p-i-n radial nanowires array based on crystalline p-type silicon (c-Si) core/hydrogenated amorphous silicon (a-Si:H) shell. By varying either the doping concentration of the c-Si core, or back contact work function we can separate and highlight the contribution to the cell’s performance of the nanowires themselves (the radial cell) from the interspace between the nanowires (the planar cell). We show that the build-in potential (V bi) in the radial and planar cells strongly depends on the doping of c-Si core and the work function of the back contact respectively. Consequently, the solar cell’s performance is degraded if either the doping concentration of the c-Si core, or/and the work function of the back contact is too low. By inserting a thin (p) a-Si:H layer between both core/absorber and back contact/absorber, the performance of the solar cell can be improved by partly fixing the V bi at both interfaces due to strong electrostatic screening effect. Depositing such a buffer layer playing the role of an electrostatic screen for charge carriers is a suggested way of enhancing the performance of solar cells based on radial p-i-n or n-i-p nanowire array.

  6. A nine-electrode probe for simultaneous measurement of all terms in the ideal radial Ohm's law

    International Nuclear Information System (INIS)

    Si, Jiahe; Wang, Zhehui

    2006-01-01

    A Nine-Electrode Probe (NEP) has been developed for simultaneous measurement of all terms in the ideal Ohm's law E+UxB=0 in the radial (r) direction in cylindrical geometry, where E is the electric field, U is the plasma flow velocity, and B is the magnetic field. The probe consists of two pairs of directional Langmuir probes ('Mach' probes) to measure the axial (z) and azimuthal (θ) plasma flows, two pairs of floating Langmuir probes at different radial positions to measure the radial electric field, and two B-dot coils to measure the axial and azimuthal magnetic field. The measurement is performed in the Flowing Magnetized Plasma (FMP) experiment. Two flow patterns are identified in the FMP experiment by the NEP. The peak-to-peak values of radial electric field fluctuation is 1.5-4 times of the mean values. Comparisons of UxBvertical bar r and E r show that E r + UxBvertical bar r is not zero within some periods of discharge. This deviation suggests non-ideal effects in Ohm's law can not be neglected

  7. MR accuracy and arthroscopic incidence of meniscal radial tears

    Energy Technology Data Exchange (ETDEWEB)

    Magee, Thomas; Shapiro, Marc; Williams, David [Department of Radiology, Neuroimaging Institute, 27 East Hibiscus Blvd., Melbourne, FL 32901 (United States)

    2002-12-01

    A meniscal radial tear is a vertical tear that involves the inner meniscal margin. The tear is most frequent in the middle third of the lateral meniscus and may extend outward in any direction. We report (1) the arthroscopic incidence of radial tears, (2) MR signs that aid in the detection of radial tears and (3) our prospective accuracy in detection of radial tears. Design and patients. Three musculoskeletal radiologists prospectively read 200 consecutive MR examinations of the knee that went on to arthroscopy by one orthopedic surgeon. MR images were assessed for location and MR characteristics of radial tears. MR criteria used for diagnosis of a radial tear were those outlined by Tuckman et al.: truncation, abnormal morphology and/or lack of continuity or absence of the meniscus on one or more MR images. An additional criterion used was abnormal increased signal in that area on fat-saturated proton density or T2-weighted coronal and sagittal images. Prospective MR readings were correlated with the arthroscopic findings.Results. Of the 200 consecutive knee arthroscopies, 28 patients had radial tears reported arthroscopically (14% incidence). MR readings prospectively demonstrated 19 of the 28 radial tears (68% sensitivity) when the criteria for diagnosis of a radial tear were truncation or abnormal morphology of the meniscus. With the use of the additional criterion of increased signal in the area of abnormal morphology on fat-saturated T2-weighted or proton density weighted sequences, the prospective sensitivity was 25 of 28 radial tears (89% sensitivity). There were no radial tears described in MR reports that were not demonstrated on arthroscopy (i.e., there were no false positive MR readings of radial tears in these 200 patients). Radial tears are commonly seen at arthroscopy. There was a 14% incidence in this series of 200 patients who underwent arthroscopy. Prospective detection of radial tears was 68% as compared with arthroscopy when the criteria as

  8. MR accuracy and arthroscopic incidence of meniscal radial tears

    International Nuclear Information System (INIS)

    Magee, Thomas; Shapiro, Marc; Williams, David

    2002-01-01

    A meniscal radial tear is a vertical tear that involves the inner meniscal margin. The tear is most frequent in the middle third of the lateral meniscus and may extend outward in any direction. We report (1) the arthroscopic incidence of radial tears, (2) MR signs that aid in the detection of radial tears and (3) our prospective accuracy in detection of radial tears. Design and patients. Three musculoskeletal radiologists prospectively read 200 consecutive MR examinations of the knee that went on to arthroscopy by one orthopedic surgeon. MR images were assessed for location and MR characteristics of radial tears. MR criteria used for diagnosis of a radial tear were those outlined by Tuckman et al.: truncation, abnormal morphology and/or lack of continuity or absence of the meniscus on one or more MR images. An additional criterion used was abnormal increased signal in that area on fat-saturated proton density or T2-weighted coronal and sagittal images. Prospective MR readings were correlated with the arthroscopic findings.Results. Of the 200 consecutive knee arthroscopies, 28 patients had radial tears reported arthroscopically (14% incidence). MR readings prospectively demonstrated 19 of the 28 radial tears (68% sensitivity) when the criteria for diagnosis of a radial tear were truncation or abnormal morphology of the meniscus. With the use of the additional criterion of increased signal in the area of abnormal morphology on fat-saturated T2-weighted or proton density weighted sequences, the prospective sensitivity was 25 of 28 radial tears (89% sensitivity). There were no radial tears described in MR reports that were not demonstrated on arthroscopy (i.e., there were no false positive MR readings of radial tears in these 200 patients). Radial tears are commonly seen at arthroscopy. There was a 14% incidence in this series of 200 patients who underwent arthroscopy. Prospective detection of radial tears was 68% as compared with arthroscopy when the criteria as

  9. Strongly correlated perovskite fuel cells

    Science.gov (United States)

    Zhou, You; Guan, Xiaofei; Zhou, Hua; Ramadoss, Koushik; Adam, Suhare; Liu, Huajun; Lee, Sungsik; Shi, Jian; Tsuchiya, Masaru; Fong, Dillon D.; Ramanathan, Shriram

    2016-06-01

    Fuel cells convert chemical energy directly into electrical energy with high efficiencies and environmental benefits, as compared with traditional heat engines. Yttria-stabilized zirconia is perhaps the material with the most potential as an electrolyte in solid oxide fuel cells (SOFCs), owing to its stability and near-unity ionic transference number. Although there exist materials with superior ionic conductivity, they are often limited by their ability to suppress electronic leakage when exposed to the reducing environment at the fuel interface. Such electronic leakage reduces fuel cell power output and the associated chemo-mechanical stresses can also lead to catastrophic fracture of electrolyte membranes. Here we depart from traditional electrolyte design that relies on cation substitution to sustain ionic conduction. Instead, we use a perovskite nickelate as an electrolyte with high initial ionic and electronic conductivity. Since many such oxides are also correlated electron systems, we can suppress the electronic conduction through a filling-controlled Mott transition induced by spontaneous hydrogen incorporation. Using such a nickelate as the electrolyte in free-standing membrane geometry, we demonstrate a low-temperature micro-fabricated SOFC with high performance. The ionic conductivity of the nickelate perovskite is comparable to the best-performing solid electrolytes in the same temperature range, with a very low activation energy. The results present a design strategy for high-performance materials exhibiting emergent properties arising from strong electron correlations.

  10. Radial propagation of microturbulence in tokamaks

    International Nuclear Information System (INIS)

    Garbet, X.; Laurent, L.; Roubin, J.P.; Samain, A.

    1992-01-01

    Energy confinement time in tokamaks exhibits a clear dependence on global plasma parameters. This is not the case for transport coefficients; their dependence on local plasma parameters cannot be precisely established. The aim of the present paper is to give a possible explanation of this behaviour; turbulence propagates radially because of departure from cylindrical geometry. This implies that the turbulence level at a given point and hence transport coefficients are not only functions of local plasma parameters. A quantitative estimate of the propagation velocity is derived from a Lagrangian formalism. Two cases are considered: the effect of toroidicity and the effect of non linear mode-mode coupling. The consequences of this model are discussed. This process does not depend on the type of instability. For the sake of simplicity only electrostatic perturbations are considered

  11. Radial particle distributions in PARMILA simulation beams

    International Nuclear Information System (INIS)

    Boicourt, G.P.

    1984-03-01

    The estimation of beam spill in particle accelerators is becoming of greater importance as higher current designs are being funded. To the present, no numerical method for predicting beam-spill has been available. In this paper, we present an approach to the loss-estimation problem that uses probability distributions fitted to particle-simulation beams. The properties of the PARMILA code's radial particle distribution are discussed, and a broad class of probability distributions are examined to check their ability to fit it. The possibility that the PARMILA distribution is a mixture is discussed, and a fitting distribution consisting of a mixture of two generalized gamma distributions is found. An efficient algorithm to accomplish the fit is presented. Examples of the relative prediction of beam spill are given. 26 references, 18 figures, 1 table

  12. Radial expansion for spinning conformal blocks

    CERN Document Server

    Costa, Miguel S.; Penedones, João; Trevisani, Emilio

    2016-07-12

    This paper develops a method to compute any bosonic conformal block as a series expansion in the optimal radial coordinate introduced by Hogervorst and Rychkov. The method reduces to the known result when the external operators are all the same scalar operator, but it allows to compute conformal blocks for external operators with spin. Moreover, we explain how to write closed form recursion relations for the coefficients of the expansions. We study three examples of four point functions in detail: one vector and three scalars; two vectors and two scalars; two spin 2 tensors and two scalars. Finally, for the case of two external vectors, we also provide a more efficient way to generate the series expansion using the analytic structure of the blocks as a function of the scaling dimension of the exchanged operator.

  13. Hydrostatic radial bearing of centrifugal pump

    International Nuclear Information System (INIS)

    Skalicky, A.

    1976-01-01

    A hydrostatic radial pump is described characterized by the fact that part of the medium off-taken from delivery is used as a lubricating medium. Two additional bodies are placed alongside a hydrostatic bearing with coils in between them and the pump shaft; the coils have an opposite pitch. The feed channel for the hydrostatic bearing pocket is linked to delivery. The coil outlets are connected to the pump suction unit. Two rotating coils placed alongside the hydrostatic bearing will considerably simplify the communication channel design and reduce the dependence on the pump shaft deflections. The addition of another rotating coil in the close vicinity of the pump shaft or directly on the shaft further increases the efficiency. The bearing can be used in designing vertical circulating pumps for the cooling circuits of nuclear reactors. (J.B.)

  14. Doubly stochastic radial basis function methods

    Science.gov (United States)

    Yang, Fenglian; Yan, Liang; Ling, Leevan

    2018-06-01

    We propose a doubly stochastic radial basis function (DSRBF) method for function recoveries. Instead of a constant, we treat the RBF shape parameters as stochastic variables whose distribution were determined by a stochastic leave-one-out cross validation (LOOCV) estimation. A careful operation count is provided in order to determine the ranges of all the parameters in our methods. The overhead cost for setting up the proposed DSRBF method is O (n2) for function recovery problems with n basis. Numerical experiments confirm that the proposed method not only outperforms constant shape parameter formulation (in terms of accuracy with comparable computational cost) but also the optimal LOOCV formulation (in terms of both accuracy and computational cost).

  15. Radial-arrayed rotary electrification for high performance triboelectric generator.

    Science.gov (United States)

    Zhu, Guang; Chen, Jun; Zhang, Tiejun; Jing, Qingshen; Wang, Zhong Lin

    2014-03-04

    Harvesting mechanical energy is an important route in obtaining cost-effective, clean and sustainable electric energy. Here we report a two-dimensional planar-structured triboelectric generator on the basis of contact electrification. The radial arrays of micro-sized sectors on the contact surfaces enable a high output power of 1.5 W (area power density of 19 mW cm(-2)) at an efficiency of 24%. The triboelectric generator can effectively harness various ambient motions, including light wind, tap water flow and normal body movement. Through a power management circuit, a triboelectric-generator-based power-supplying system can provide a constant direct-current source for sustainably driving and charging commercial electronics, immediately demonstrating the feasibility of the triboelectric generator as a practical power source. Given exceptional power density, extremely low cost and unique applicability resulting from distinctive mechanism and structure, the triboelectric generator can be applied not only to self-powered electronics but also possibly to power generation at a large scale.

  16. Anomalous Medial Branch of Radial Artery: A Rare Variant

    Directory of Open Access Journals (Sweden)

    Surbhi Wadhwa

    2016-10-01

    Full Text Available Radial artery is an important consistent vessel of the upper limb. It is a useful vascular access site for coronary procedures and its reliable anatomy has resulted in an elevation of radial forearm flaps for reconstructive surgeries of head and neck. Technical failures, in both the procedures, are mainly due to anatomical variations, such as radial loops, ectopic radial arteries or tortuosity in the vessel. We present a rare and a unique anomalous medial branch of the radial artery spiraling around the flexor carpi radialis muscle in the forearm with a high rising superficial palmar branch of radial artery. Developmentally it probably is a remanent of the normal pattern of capillary vessel maintenance and regression. Such a case is of importance for reconstructive surgeons and coronary interventionists, especially in view of its unique medial and deep course.

  17. Radial extension of drift waves in presence of velocity profiles

    International Nuclear Information System (INIS)

    Sen, S.; Weiland, J.

    1994-01-01

    The effect of a radially varying poloidal velocity field on the recently found radially extended toroidal drift waves is investigated analytically. The role of velocity curvature (υ φ '') is found to have robust effects on the radial model structure of the mode. For a positive value of the curvature (Usually found in the H-mode edges) the radial model envelope, similar to the sheared slab case, becomes fully outgoing. The mode is therefore stable. On the other hand, for a negative value of the curvature (usually observed in the L-mode edges) all the characteristics of conventional drift waves return back. The radial mode envelope reduces to a localized Gaussian shape and the mode is therefore unstable again for typical (magnetic) shear values in tokamaks. Velocity shear (υ φ ??) on the other hand is found to have rather insignificant role both in determining the radial model structure and stability

  18. Pervasive Electricity Distribution System

    Directory of Open Access Journals (Sweden)

    Muhammad Usman Tahir

    2017-06-01

    Full Text Available Now a days a country cannot become economically strong until and unless it has enough electrical power to fulfil industrial and domestic needs. Electrical power being the pillar of any country’s economy, needs to be used in an efficient way. The same step is taken here by proposing a new system for energy distribution from substation to consumer houses, also it monitors the consumer consumption and record data. Unlike traditional manual Electrical systems, pervasive electricity distribution system (PEDS introduces a fresh perspective to monitor the feeder line status at distribution and consumer level. In this system an effort is taken to address the issues of electricity theft, manual billing, online monitoring of electrical distribution system and automatic control of electrical distribution points. The project is designed using microcontroller and different sensors, its GUI is designed in Labview software.

  19. Radial stability of anisotropic strange quark stars

    Energy Technology Data Exchange (ETDEWEB)

    Arbañil, José D.V.; Malheiro, M., E-mail: jose.arbanil@upn.pe, E-mail: malheiro@ita.br [ITA—Instituto Tecnológico de Aeronáutica—Departamento de Física, 12228-900, São José dos Campos, São Paulo (Brazil)

    2016-11-01

    The influence of the anisotropy in the equilibrium and stability of strange stars is investigated through the numerical solution of the hydrostatic equilibrium equation and the radial oscillation equation, both modified from their original version to include this effect. The strange matter inside the quark stars is described by the MIT bag model equation of state. For the anisotropy two different kinds of local anisotropic σ = p {sub t} − p {sub r} are considered, where p {sub t} and p {sub r} are respectively the tangential and the radial pressure: one that is null at the star's surface defined by p {sub r} ( R ) = 0, and one that is nonnull at the surface, namely, σ {sub s} = 0 and σ {sub s} {sub ≠} {sub 0}. In the case σ {sub s} = 0, the maximum mass value and the zero frequency of oscillation are found at the same central energy density, indicating that the maximum mass marks the onset of the instability. For the case σ {sub s} {sub ≠} {sub 0}, we show that the maximum mass point and the zero frequency of oscillation coincide in the same central energy density value only in a sequence of equilibrium configurations with the same value of σ {sub s} . Thus, the stability star regions are determined always by the condition dM / d ρ {sub c} {sub >} {sub 0} only when the tangential pressure is maintained fixed at the star surface's p {sub t} ( R ). These results are also quite important to analyze the stability of other anisotropic compact objects such as neutron stars, boson stars and gravastars.

  20. Strong-interaction nonuniversality

    International Nuclear Information System (INIS)

    Volkas, R.R.; Foot, R.; He, X.; Joshi, G.C.

    1989-01-01

    The universal QCD color theory is extended to an SU(3) 1 direct product SU(3) 2 direct product SU(3) 3 gauge theory, where quarks of the ith generation transform as triplets under SU(3)/sub i/ and singlets under the other two factors. The usual color group is then identified with the diagonal subgroup, which remains exact after symmetry breaking. The gauge bosons associated with the 16 broken generators then form two massive octets under ordinary color. The interactions between quarks and these heavy gluonlike particles are explicitly nonuniversal and thus an exploration of their physical implications allows us to shed light on the fundamental issue of strong-interaction universality. Nonuniversality and weak flavor mixing are shown to generate heavy-gluon-induced flavor-changing neutral currents. The phenomenology of these processes is studied, as they provide the major experimental constraint on the extended theory. Three symmetry-breaking scenarios are presented. The first has color breaking occurring at the weak scale, while the second and third divorce the two scales. The third model has the interesting feature of radiatively induced off-diagonal Kobayashi-Maskawa matrix elements

  1. John Strong (1941 - 2006)

    CERN Multimedia

    Wickens, F

    Our friend and colleague John Strong was cruelly taken from us by a brain tumour on Monday 31st July, a few days before his 65th birthday John started his career working with a group from Westfield College, under the leadership of Ted Bellamy. He obtained his PhD and spent the early part of his career on experiments at Rutherford Appleton Laboratory (RAL), but after the early 1970s his research was focussed on experiments in CERN. Over the years he made a number of notable contributions to experiments in CERN: The Omega spectrometer adopted a system John had originally developed for experiments at RAL using vidicon cameras to record the sparks in the spark chambers; He contributed to the success of NA1 and NA7, where he became heavily involved in the electronic trigger systems; He was responsible for the second level trigger system for the ALEPH detector and spent five years leading a team that designed and built the system, which ran for twelve years with only minor interventions. Following ALEPH he tur...

  2. Stirring Strongly Coupled Plasma

    CERN Document Server

    Fadafan, Kazem Bitaghsir; Rajagopal, Krishna; Wiedemann, Urs Achim

    2009-01-01

    We determine the energy it takes to move a test quark along a circle of radius L with angular frequency w through the strongly coupled plasma of N=4 supersymmetric Yang-Mills (SYM) theory. We find that for most values of L and w the energy deposited by stirring the plasma in this way is governed either by the drag force acting on a test quark moving through the plasma in a straight line with speed v=Lw or by the energy radiated by a quark in circular motion in the absence of any plasma, whichever is larger. There is a continuous crossover from the drag-dominated regime to the radiation-dominated regime. In the crossover regime we find evidence for significant destructive interference between energy loss due to drag and that due to radiation as if in vacuum. The rotating quark thus serves as a model system in which the relative strength of, and interplay between, two different mechanisms of parton energy loss is accessible via a controlled classical gravity calculation. We close by speculating on the implicati...

  3. Turbulent fluctuations and radial transport in the scrape-off layer of the ASDEX tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Endler, M [Max-Planck-Institut fuer Plasmaphysik, EURATOM Association, 85740 Garching (Germany); Giannone, L. [Max-Planck-Institut fuer Plasmaphysik, EURATOM Association, 85740 Garching (Germany); McCormick, K [Max-Planck-Institut fuer Plasmaphysik, EURATOM Association, 85740 Garching (Germany); Niedermeyer, H [Max-Planck-Institut fuer Plasmaphysik, EURATOM Association, 85740 Garching (Germany); Rudyj, A [Max-Planck-Institut fuer Plasmaphysik, EURATOM Association, 85740 Garching (Germany); Theimer, G [Max-Planck-Institut fuer Plasmaphysik, EURATOM Association, 85740 Garching (Germany); Tsois, N [NCSR ` Demokritos` , Athens (Greece); ASDEX Team

    1995-04-01

    Electrostatic fluctuations have been measured in the scrape-off layer of ASDEX by Langmuir probes and by observation of H{sub {alpha}} light with high poloidal and temporal resolution. It was demonstrated that these fluctuations contribute a significant, if not dominant, fraction of the ``anomalous`` radial particle transport. A model for an instability mechanism specific to the SOL is presented including density, temperature and electric potential fluctuations. From this model mixing length estimates for the radial transport and resulting density and pressure gradients in the SOL are derived and compared to measurements in the mid-plane and in the divertor of ASDEX. In spite of several simplifications in the model a quantitative agreement up to factors of 1-3 and a qualitative agreement for variations of discharge parameters is achieved between the model predictions and the measurements. ((orig.)).

  4. Turbulent fluctuations and radial transport in the scrape-off layer of the ASDEX tokamak

    International Nuclear Information System (INIS)

    Endler, M.; Giannone, L.; McCormick, K.; Niedermeyer, H.; Rudyj, A.; Theimer, G.; Tsois, N.

    1995-01-01

    Electrostatic fluctuations have been measured in the scrape-off layer of ASDEX by Langmuir probes and by observation of H α light with high poloidal and temporal resolution. It was demonstrated that these fluctuations contribute a significant, if not dominant, fraction of the ''anomalous'' radial particle transport. A model for an instability mechanism specific to the SOL is presented including density, temperature and electric potential fluctuations. From this model mixing length estimates for the radial transport and resulting density and pressure gradients in the SOL are derived and compared to measurements in the mid-plane and in the divertor of ASDEX. In spite of several simplifications in the model a quantitative agreement up to factors of 1-3 and a qualitative agreement for variations of discharge parameters is achieved between the model predictions and the measurements. ((orig.))

  5. Manipulation of radial-variant polarization for creating tunable bifocusing spots.

    Science.gov (United States)

    Gu, Bing; Pan, Yang; Wu, Jia-Lu; Cui, Yiping

    2014-02-01

    We propose and generate a new radial-variant vector field (RV-VF) with a distribution of states of polarization described by the square of the radius and exploit its focusing property. Theoretically, we present the analytical expressions for the three-dimensional electric field of the vector field focused by a thin lens under the nonparaxial and paraxial approximations based on the vectorial Rayleigh-Sommerfeld formulas. Numerical simulations indicate that this focused field exhibits bifocusing spots along the optical axis. The underlying mechanism for generating the bifocusing property is analyzed in detail. We give the analytical formula for the interval between two foci. Experimentally, we generate the RV-VFs with alterable topological charge and demonstrate that the interval between two foci is controllable by tuning the radial topological charge. This particular focal field has specific applications for biparticle trapping, manipulating, alignment, transportation, and accelerating along the optical axis.

  6. Turbulence simulations of blob formation and radial propagation in toroidally magnetized plasmas

    DEFF Research Database (Denmark)

    Garcia, O.E.; Naulin, V.; Nielsen, A.H.

    2006-01-01

    the presence of long- range correlations in the particle density fluctuations. Finally, conditional statistics of the particle flux demonstrates the intermittency of the turbulent plasma transport and the quasi-periodic apparency of blob structures due to bursting in the global turbulence level....... of particles and heat, which is coupled to a scrape-off layer with linear damping terms for all dependent variables corresponding to transport along open magnetic field lines. The formation of blob structures is related to profile variations caused by bursting in the global turbulence level, which is due...... to a dynamical regulation by self- sustained differential rotation of the plasma layer. Radial propagation of the blob structures follows from a vertical charge polarization due to magnetic guiding centre drifts in the toroidally magnetized plasma. Statistical analysis of the particle density, radial electric...

  7. Scattering by multiple parallel radially stratified infinite cylinders buried in a lossy half space.

    Science.gov (United States)

    Lee, Siu-Chun

    2013-07-01

    The theoretical solution for scattering by an arbitrary configuration of closely spaced parallel infinite cylinders buried in a lossy half space is presented in this paper. The refractive index and permeability of the half space and cylinders are complex in general. Each cylinder is radially stratified with a distinct complex refractive index and permeability. The incident radiation is an arbitrarily polarized plane wave propagating in the plane normal to the axes of the cylinders. Analytic solutions are derived for the electric and magnetic fields and the Poynting vector of backscattered radiation emerging from the half space. Numerical examples are presented to illustrate the application of the scattering solution to calculate backscattering from a lossy half space containing multiple homogeneous and radially stratified cylinders at various depths and different angles of incidence.

  8. Determination of radial profile of ICF hot spot's state by multi-objective parameters optimization

    International Nuclear Information System (INIS)

    Dong Jianjun; Deng Bo; Cao Zhurong; Ding Yongkun; Jiang Shaoen

    2014-01-01

    A method using multi-objective parameters optimization is presented to determine the radial profile of hot spot temperature and density. And a parameter space which contain five variables: the temperatures at center and the interface of fuel and remain ablator, the maximum model density of remain ablator, the mass ratio of remain ablator to initial ablator and the position of interface between fuel and the remain ablator, is used to described the hot spot radial temperature and density. Two objective functions are set as the variances of normalized intensity profile from experiment X-ray images and the theory calculation. Another objective function is set as the variance of experiment average temperature of hot spot and the average temperature calculated by theoretical model. The optimized parameters are obtained by multi-objective genetic algorithm searching for the five dimension parameter space, thereby the optimized radial temperature and density profiles can be determined. The radial temperature and density profiles of hot spot by experiment data measured by KB microscope cooperating with X-ray film are presented. It is observed that the temperature profile is strongly correlated to the objective functions. (authors)

  9. A New Filtering Algorithm Utilizing Radial Velocity Measurement

    Institute of Scientific and Technical Information of China (English)

    LIU Yan-feng; DU Zi-cheng; PAN Quan

    2005-01-01

    Pulse Doppler radar measurements consist of range, azimuth, elevation and radial velocity. Most of the radar tracking algorithms in engineering only utilize position measurement. The extended Kalman filter with radial velocity measureneut is presented, then a new filtering algorithm utilizing radial velocity measurement is proposed to improve tracking results and the theoretical analysis is also given. Simulation results of the new algorithm, converted measurement Kalman filter, extended Kalman filter are compared. The effectiveness of the new algorithm is verified by simulation results.

  10. Vitreous veils and radial lattice in Marshall syndrome.

    Science.gov (United States)

    Brubaker, Jacob W; Mohney, Brian G; Pulido, Jose S; Babovic-Vuksanovic, Dusica

    2008-12-01

    To report the findings of membranous vitreous veils and radial lattice in a child with Marshall syndrome. Observational case report. Retrospective review of medical records and fundus photograph of a 6-year-old boy with Marshall syndrome. Vitreoretinal findings were significant for bilateral membranous vitreous veils and radial lattice degeneration. This case demonstrates the occurrence of vitreous veils and radial lattice degeneration in patients with Marshall syndrome.

  11. Pseudarthrosis of radial shaft with dislocation of heads of radial and ulnar bones (case report

    Directory of Open Access Journals (Sweden)

    M. E. Puseva

    2013-01-01

    Full Text Available The authors presented a rare clinical case - the injury of forearm complicated by the formation of the pseudarthrosis of the radial shaft in combination with old dislocation of heads the radius and ulna. The differentiated approach to the choice of surgical tactics was proposed, which consists of several consistent stages: taking free autotransplant from the crest of iliac bone, resection of pseudarthrosis of radius with replacement of the bone defect by the graft for restoration of anatomic length, conducting combined strained osteosynthesis and elimination of dislocation of a head of radial and ulnar bones by transosseous osteosynthesis. The chosen treatment strategy allowed to restore the anatomy and function of the upper extremity.

  12. Nonlinear dynamics of semiconductors in strong THz electric fields

    DEFF Research Database (Denmark)

    Tarekegne, Abebe Tilahun

    In this thesis, we investigate nonlinear interactions of an intense terahertz (THz) field with semiconductors, in particular the technologically relevant materials silicon and silicon carbide. We reveal the time-resolved dynamics of the nonlinear processes by pump-probe experiments that involve...

  13. Kubo conductivity of a strongly magnetized two-dimensional plasma.

    Science.gov (United States)

    Montgomery, D.; Tappert, F.

    1971-01-01

    The Kubo formula is used to evaluate the bulk electrical conductivity of a two-dimensional guiding-center plasma in a strong dc magnetic field. The particles interact only electrostatically. An ?anomalous' electrical conductivity is derived for this system, which parallels a recent result of Taylor and McNamara for the coefficient of spatial diffusion.

  14. Neurogenic Radial Glia-like Cells in Meninges Migrate and Differentiate into Functionally Integrated Neurons in the Neonatal Cortex.

    Science.gov (United States)

    Bifari, Francesco; Decimo, Ilaria; Pino, Annachiara; Llorens-Bobadilla, Enric; Zhao, Sheng; Lange, Christian; Panuccio, Gabriella; Boeckx, Bram; Thienpont, Bernard; Vinckier, Stefan; Wyns, Sabine; Bouché, Ann; Lambrechts, Diether; Giugliano, Michele; Dewerchin, Mieke; Martin-Villalba, Ana; Carmeliet, Peter

    2017-03-02

    Whether new neurons are added in the postnatal cerebral cortex is still debated. Here, we report that the meninges of perinatal mice contain a population of neurogenic progenitors formed during embryonic development that migrate to the caudal cortex and differentiate into Satb2 + neurons in cortical layers II-IV. The resulting neurons are electrically functional and integrated into local microcircuits. Single-cell RNA sequencing identified meningeal cells with distinct transcriptome signatures characteristic of (1) neurogenic radial glia-like cells (resembling neural stem cells in the SVZ), (2) neuronal cells, and (3) a cell type with an intermediate phenotype, possibly representing radial glia-like meningeal cells differentiating to neuronal cells. Thus, we have identified a pool of embryonically derived radial glia-like cells present in the meninges that migrate and differentiate into functional neurons in the neonatal cerebral cortex. Copyright © 2016 Elsevier Inc. All rights reserved.

  15. PREFACE: Strongly correlated electron systems Strongly correlated electron systems

    Science.gov (United States)

    Saxena, Siddharth S.; Littlewood, P. B.

    2012-07-01

    make use of 'small' electrons packed to the highest possible density. These are by definition 'strongly correlated'. For example: good photovoltaics must be efficient optical absorbers, which means that photons will generate tightly bound electron-hole pairs (excitons) that must then be ionised at a heterointerface and transported to contacts; efficient solid state refrigeration depends on substantial entropy changes in a unit cell, with large local electrical or magnetic moments; efficient lighting is in a real sense the inverse of photovoltaics; the limit of an efficient battery is a supercapacitor employing mixed valent ions; fuel cells and solar to fuel conversion require us to understand electrochemistry on the scale of a single atom; and we already know that the only prospect for effective high temperature superconductivity involves strongly correlated materials. Even novel IT technologies are now seen to have value not just for novel function but also for efficiency. While strongly correlated electron systems continue to excite researchers and the public alike due to the fundamental science issues involved, it seems increasingly likely that support for the science will be leveraged by its impact on energy and sustainability. Strongly correlated electron systems contents Strongly correlated electron systemsSiddharth S Saxena and P B Littlewood Magnetism, f-electron localization and superconductivity in 122-type heavy-fermion metalsF Steglich, J Arndt, O Stockert, S Friedemann, M Brando, C Klingner, C Krellner, C Geibel, S Wirth, S Kirchner and Q Si High energy pseudogap and its evolution with doping in Fe-based superconductors as revealed by optical spectroscopyN L Wang, W Z Hu, Z G Chen, R H Yuan, G Li, G F Chen and T Xiang Structural investigations on YbRh2Si2: from the atomic to the macroscopic length scaleS Wirth, S Ernst, R Cardoso-Gil, H Borrmann, S Seiro, C Krellner, C Geibel, S Kirchner, U Burkhardt, Y Grin and F Steglich Confinement of chiral magnetic

  16. Design of radial reinforcement for prestressed concrete containments

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Shen, E-mail: swang@bechtel.com [Bechtel Power Corporation, 5275 Westview Drive, BP2-2C3, Frederick, MD 21703 (United States); Munshi, Javeed A., E-mail: jamunshi@bechtel.com [Bechtel Power Corporation, 5275 Westview Drive, BP2-2C3, Frederick, MD 21703 (United States)

    2013-02-15

    Highlights: ► A rigorous formulae is proposed to calculate radial stress within prestressed concrete containments. ► The proposed method is validated by finite element analysis in an illustrative practical example. ► A partially prestressed condition is more critical than a fully prestressed condition for radial tension. ► Practical design consideration is provided for detailing of radial reinforcement. -- Abstract: Nuclear containments are critical components for safety of nuclear power plants. Failure can result in catastrophic safety consequences as a result of leakage of radiation. Prestressed concrete containments have been used in large nuclear power plants with significant design internal pressure. These containments are generally reinforced with prestressing tendons in the circumferential (hoop) and meridional (vertical) directions. The curvature effect of the tendons introduces radial tensile stresses in the concrete shell which are generally neglected in the design of such structures. It is assumed that such tensile radial stresses are small as such no radial reinforcement is provided for this purpose. But recent instances of significant delaminations in Crystal River Unit 3 in Florida have elevated the need for reevaluation of the radial tension issue in prestressed containment. Note that currently there are no well accepted industry standards for design and detailing of radial reinforcement. This paper discusses the issue of radial tension in prestressed cylindrical and dome shaped structures and proposes formulae to calculate radial stresses. A practical example is presented to illustrate the use of the proposed method which is then verified by using state of art finite element analysis. This paper also provides some practical design consideration for detailing of radial reinforcement in prestressed containments.

  17. Electro-thermal analysis and integration issues of lithium ion battery for electric vehicles

    International Nuclear Information System (INIS)

    Saw, L.H.; Ye, Y.; Tay, A.A.O.

    2014-01-01

    Highlights: • We modeled the electrical and thermal behavior of the Li-ion battery. • We validated the simulation results with experimental studies. • We compared the thermal performance of different size of cylindrical cells. • We investigated the integration issues of cylindrical cells into battery pack. - Abstract: Electrical and thermal characteristics of lithium-ion battery packs in electric vehicles in different operating conditions are important in order to design the battery pack thermal management system. In this work, electrical and thermal behaviors of different size of LiFePO 4 cylindrical cells are investigated under various operating conditions. The simulation results show good agreement with the experimental data under various operating modes. Due to the large thermal resistance of layered active material in a Li-ion cell, the temperature difference in the radial direction is significantly correlated with a diameter of cell and I t -rates. Compared with natural convection, strong forced convection will reduce the temperature uniformity in the cell and accelerate the thermal aging rate. Lastly, integration issues of the cells into a battery pack are discussed from mechanical, electrical, thermal, control and monitoring, manufacturing and maintenance aspects. These issues could impact the performance, cost, driving range and life cycle of the battery pack in electric vehicles

  18. Strongly interacting matter in magnetic fields

    CERN Document Server

    Landsteiner, Karl; Schmitt, Andreas; Yee, Ho-Ung

    2013-01-01

    The physics of strongly interacting matter in an external magnetic field is presently emerging as a topic of great cross-disciplinary interest for particle, nuclear, astro- and condensed matter physicists. It is known that strong magnetic fields are created in heavy ion collisions, an insight that has made it possible to study a variety of surprising and intriguing phenomena that emerge from the interplay of quantum anomalies, the topology of non-Abelian gauge fields, and the magnetic field. In particular, the non-trivial topological configurations of the gluon field induce a non-dissipative electric current in the presence of a magnetic field. These phenomena have led to an extended formulation of relativistic hydrodynamics, called chiral magnetohydrodynamics. Hitherto unexpected applications in condensed matter physics include graphene and topological insulators. Other fields of application include astrophysics, where strong magnetic fields exist in magnetars and pulsars. Last but not least, an important ne...

  19. The innate origin of radial and vertical gradients in a simulated galaxy disc

    Science.gov (United States)

    Navarro, Julio F.; Yozin, Cameron; Loewen, Nic; Benítez-Llambay, Alejandro; Fattahi, Azadeh; Frenk, Carlos S.; Oman, Kyle A.; Schaye, Joop; Theuns, Tom

    2018-05-01

    We examine the origin of radial and vertical gradients in the age/metallicity of the stellar component of a galaxy disc formed in the APOSTLE cosmological hydrodynamical simulations. Some of these gradients resemble those in the Milky Way, where they have sometimes been interpreted as due to internal evolution, such as scattering off giant molecular clouds, radial migration driven by spiral patterns, or orbital resonances with a bar. Secular processes play a minor role in the simulated galaxy, which lacks strong spiral or bar patterns, and where such gradients arise as a result of the gradual enrichment of a gaseous disc that is born thick but thins as it turns into stars and settles into centrifugal equilibrium. The settling is controlled by the feedback of young stars; which links the star formation, enrichment, and equilibration time-scales, inducing radial and vertical gradients in the gaseous disc and its descendent stars. The kinematics of coeval stars evolve little after birth and provide a faithful snapshot of the gaseous disc structure at the time of their formation. In this interpretation, the age-velocity dispersion relation would reflect the gradual thinning of the disc rather than the importance of secular orbit scattering; the outward flaring of stars would result from the gas disc flare rather than from radial migration; and vertical gradients would arise because the gas disc gradually thinned as it enriched. Such radial and vertical trends might just reflect the evolving properties of the parent gaseous disc, and are not necessarily the result of secular evolutionary processes.

  20. Shallow crustal radial anisotropy beneath the Tehran basin of Iran from seismic ambient noise tomography

    Science.gov (United States)

    Shirzad, Taghi; Shomali, Z. Hossein

    2014-06-01

    We studied the shear wave velocity structure and radial anisotropy beneath the Tehran basin by analyzing the Rayleigh wave and Love wave empirical Green's functions obtained from cross-correlation of seismic ambient noise. Approximately 199 inter-station Rayleigh and Love wave empirical Green's functions with sufficient signal-to-noise ratios extracted from 30 stations with various sensor types were used for phase velocity dispersion analysis of periods ranging from 1 to 7 s using an image transformation analysis technique. Dispersion curves extracted from the phase velocity maps were inverted based on non-linear damped least squares inversion method to obtain a quasi-3D model of crustal shear wave velocities. The data used in this study provide an unprecedented opportunity to resolve the spatial distribution of radial anisotropy within the uppermost crust beneath the Tehran basin. The quasi-3D shear wave velocity model obtained in this analysis delineates several distinct low- and high-velocity zones that are generally separated by geological boundaries. High-shear-velocity zones are located primarily around the mountain ranges and extend to depths of 2.0 km, while the low-shear-velocity zone is located near regions with sedimentary layers. In the shallow subsurface, our results indicate strong radial anisotropy with negative magnitude (VSV > VSH) primarily associated with thick sedimentary deposits, reflecting vertical alignment of cracks. With increasing depth, the magnitude of the radial anisotropy shifts from predominantly negative (less than -10%) to predominantly positive (greater than 5%). Our results show a distinct change in radial anisotropy between the uppermost sedimentary layer and the bedrock.

  1. Observational hints of radial migration in disc galaxies from CALIFA

    NARCIS (Netherlands)

    Ruiz-Lara, T.; Pérez, I.; Florido, E.; Sánchez-Blázquez, P.; Méndez-Abreu, J.; Sánchez-Menguiano, L.; Sánchez, S. F.; Lyubenova, M.; Falcón-Barroso, J.; van de Ven, G.; Marino, R. A.; de Lorenzo-Cáceres, A.; Catalán-Torrecilla, C.; Costantin, L.; Bland-Hawthorn, J.; Galbany, L.; García-Benito, R.; Husemann, B.; Kehrig, C.; Márquez, I.; Mast, D.; Walcher, C. J.; Zibetti, S.; Ziegler, B.

    2017-01-01

    Context. According to numerical simulations, stars are not always kept at their birth galactocentric distances but they have a tendency to migrate. The importance of this radial migration in shaping galactic light distributions is still unclear. However, if radial migration is indeed important,

  2. Radial supports of face motors with slack compensation

    Energy Technology Data Exchange (ETDEWEB)

    Kuznetsova, I I; Gelman, A B; Krekina, T V

    1982-01-01

    The design of a radial support of a face motor with slack compensation is described, and gives the results of field tests which confirm the performance capacity of the experimental support both from the viewpoint of durability, and in relation to preventing radial slack of the face motor shaft.

  3. Radial Color Gradient in a Globular Cluster 1. M68

    Directory of Open Access Journals (Sweden)

    Sukyoung Yi

    1990-12-01

    Full Text Available Stars in M68 from the observed color-magnitude diagrams with CCD were integrated to find any radial gradient. The result shows that M68 has a slightly bluer core. The main cause of these calculated radial color variations seems to come from the random distribution of giants.

  4. Modelling and analysis of radial thermal stresses and temperature ...

    African Journals Online (AJOL)

    A theoretical investigation has been undertaken to study operating temperatures, heat fluxes and radial thermal stresses in the valves of a modern diesel engine with and without air-cavity. Temperatures, heat fluxes and radial thermal stresses were measured theoretically for both cases under all four thermal loading ...

  5. Radiographic study of distal radial physeal closure in thoroughbred horses

    International Nuclear Information System (INIS)

    Vulcano, L.C.; Mamprim, M.J.; Muniz, L.M.R.; Moreira, A.F.; Luna, S.P.L.

    1997-01-01

    Monthly radiography was performed to study distal radial physeal closure in ten male and ten female Throughbred horses. The height, thoracic circumference and metacarpus circumference were also measured, Distal radial physeal closure time was sooner in females than males, and took 701 +/- 37 and 748 +/- 55 days respectively

  6. Radial Velocities of 41 Kepler Eclipsing Binaries

    Science.gov (United States)

    Matson, Rachel A.; Gies, Douglas R.; Guo, Zhao; Williams, Stephen J.

    2017-12-01

    Eclipsing binaries are vital for directly determining stellar parameters without reliance on models or scaling relations. Spectroscopically derived parameters of detached and semi-detached binaries allow us to determine component masses that can inform theories of stellar and binary evolution. Here we present moderate resolution ground-based spectra of stars in close binary systems with and without (detected) tertiary companions observed by NASA’s Kepler mission and analyzed for eclipse timing variations. We obtain radial velocities and spectroscopic orbits for five single-lined and 35 double-lined systems, and confirm one false positive eclipsing binary. For the double-lined spectroscopic binaries, we also determine individual component masses and examine the mass ratio {M}2/{M}1 distribution, which is dominated by binaries with like-mass pairs and semi-detached classical Algol systems that have undergone mass transfer. Finally, we constrain the mass of the tertiary component for five double-lined binaries with previously detected companions.

  7. Nonlinear radial propagation of drift wave turbulence

    International Nuclear Information System (INIS)

    Prakash, M.

    1985-01-01

    We study the linear and the nonlinear radial propagation of drift wave energy in an inhomogeneous plasma. The drift mode excited in such a plasma is dispersive in nature. The drift wave energy spreads out symmetrically along the direction of inhomogeneity with a finite group velocity. To study the effect of the nonlinear coupling on the propagation of energy in a collision free plasma, we solve the Hasegawa-Mima equation as a mixed initial boundary-value problem. The solutions of the linearized equation are used to check the reliability of our numerical calculations. Additional checks are also performed on the invariants of the system. Our results reveal that a pulse gets distorted as it propagates through the medium. The peak of the pulse propagates with a finite velocity that depends on the amplitude of the initial pulse. The polarity of propagation depends on the initial parameters of the pulse. We have also studied drift wave propagation in a resistive plasma. The Hasegawa-Wakatani equations are used to investigate this problem

  8. THE NIRSPEC ULTRACOOL DWARF RADIAL VELOCITY SURVEY

    International Nuclear Information System (INIS)

    Blake, Cullen H.; Charbonneau, David; White, Russel J.

    2010-01-01

    We report the results of an infrared Doppler survey designed to detect brown dwarf and giant planetary companions to a magnitude-limited sample of ultracool dwarfs. Using the NIRSPEC spectrograph on the Keck II telescope, we obtained approximately 600 radial velocity (RV) measurements over a period of six years of a sample of 59 late-M and L dwarfs spanning spectral types M8/L0 to L6. A subsample of 46 of our targets has been observed on three or more epochs. We rely on telluric CH 4 absorption features in Earth's atmosphere as a simultaneous wavelength reference and exploit the rich set of CO absorption features found in the K-band spectra of cool stars and brown dwarfs to measure RVs and projected rotational velocities. For a bright, slowly rotating M dwarf standard we demonstrate an RV precision of 50 m s -1 and for slowly rotating L dwarfs we achieve a typical RV precision of approximately 200 m s -1 . This precision is sufficient for the detection of close-in giant planetary companions to mid-L dwarfs as well as more equal mass spectroscopic binary systems with small separations (a +0.7 -0.6 Gyr, similar to that of nearby sun-like stars. We simulate the efficiency with which we detect spectroscopic binaries and find that the rate of tight (a +8.6 -1.6 %, consistent with recent estimates in the literature of a tight binary fraction of 3%-4%.

  9. Vortex Ring Dynamics in Radially Confined Domains

    Science.gov (United States)

    Stewart, Kelley; Niebel, Casandra; Jung, Sunghwan; Vlachos, Pavlos

    2010-11-01

    Vortex ring dynamics have been studied extensively in semi-infinite quiescent volumes. However, very little is known about vortex-ring formation in wall-bounded domains where vortex wall interaction will affect both the vortex ring pinch-off and propagation velocity. This study addresses this limitation and studies vortex formation in radially confined domains to analyze the affect of vortex-ring wall interaction on the formation and propagation of the vortex ring. Vortex rings were produced using a pneumatically driven piston cylinder arrangement and were ejected into a long cylindrical tube which defined the confined downstream domain. A range of confinement domains were studied with varying confinement diameters Velocity field measurements were performed using planar Time Resolved Digital Particle Image Velocimetry (TRDPIV) and were processed using an in-house developed cross-correlation PIV algorithm. The experimental analysis was used to facilitate the development of a theoretical model to predict the variations in vortex ring circulation over time within confined domains.

  10. The dust acoustic wave in a bounded dusty plasma with strong electrostatic interactions between dust grains

    International Nuclear Information System (INIS)

    Shukla, Nitin; Shukla, P.K.

    2011-01-01

    The dispersion relation for the dust acoustic wave (DAW) in an unmagnetized dusty plasma cylindrical waveguide is derived, accounting for strong electrostatic interactions between charged dust grains. It is found that the boundary effect limits the radial extent of the DAW. The present result should be helpful for understanding the frequency spectrum of the DAW in a dusty plasma waveguide with strongly coupled charged dust grains. - Highlights: → We study the dust acoustic wave (DAW) in a bounded plasma. → We account for interactions between dust grains. → The boundary effect limits the radial extent of the DAW.

  11. Electric field and transport in W7-AS

    International Nuclear Information System (INIS)

    Kick, M.; Maassberg, H.; Anton, M.; Baldzuhn, J.; Endler, M.; Goerner, C.; Hirsch, M.; Weller, A.; Zoletnik, S.

    1999-01-01

    At W7-AS, confinement properties are analysed and compared mainly with neoclassical predictions for quite different conditions. Low-density electron cyclotron resonance heating (ECRH) discharges allow access to the very-long-mean-free-path regime for electrons (T e up to 6 keV) whereas pure neutral beam injections (NBI) and combined NBI/ECRH discharges at high density (T i approx. T e ≥ 1 keV at n e approx. 10 20 m -3 ) lead to high performance (τ B up to 50 ms). Depending on the achieved temperatures, the experimental transport analysis in the plasma core is consistent with the neoclassical predictions. The experimentally observed 'electron root' feature with strong E r >0 is driven by the convective flux of ripple-trapped suprathermal electrons generated by the ECRH absorption. 'Optimum' confinement is obtained in discharges with narrow density, but broad temperature profiles with steep gradients in the region of low densities and strong E r <0 close to the plasma edge. The large radial electric fields, both positive and negative, strongly reduce neoclassical transport. The achieved temperatures, however, are limited by the strong temperature dependence of the neoclassical transport. (author)

  12. VizieR Online Data Catalog: l Car radial velocity curves (Anderson, 2016)

    Science.gov (United States)

    Anderson, R. I.

    2018-02-01

    Line-of-sight (radial) velocities of the long-period classical Cepheid l Carinae were measured from 925 high-quality optical spectra recorded using the fiber-fed high-resolution (R~60,000) Coralie spectrograph located at the Euler telescope at La Silla Observatory, Chile. The data were taken between 2014 and 2016. This is the full version of Tab. 2 presented partially in the paper. Line shape parameters (depth, width, asymmetry) are listed for the computed cross-correlation profiles (CCFs). Radial velocities were determined using different techniques (Gaussian, bi-Gaussian) and measured on CCFs computed using three different numerical masks (G2, weak lines, strong lines). (1 data file).

  13. REVERSED TREND OF RADIAL DISTRIBUTION OF SUBPOPULATIONS IN THE GLOBULAR CLUSTERS NGC 362 AND NGC 6723

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Dongwook; Lee, Young-Wook; Pasquato, Mario [Center for Galaxy Evolution Research and Department of Astronomy, Yonsei University, Seoul 03722 (Korea, Republic of); Han, Sang-Il; Roh, Dong-Goo, E-mail: dwlim@galaxy.yonsei.ac.kr, E-mail: ywlee2@yonsei.ac.kr [Korea Astronomy and Space Science Institute, Daejeon 34055 (Korea, Republic of)

    2016-12-01

    Most globular clusters (GCs) are now known to host multiple stellar populations with different abundances of light elements. Here we use narrow-band photometry and low-resolution spectroscopy for NGC 362 and NGC 6723 to investigate their chemical properties and radial distributions of subpopulations. We confirm that NGC 362 and NGC 6723 are among the GCs with multiple populations showing bimodal CN distribution and CN–CH anticorrelation without a significant spread in calcium abundance. These two GCs show more centrally concentrated CN-weak, earlier generation stars compared to the CN-strong, later generation stars. These trends are reversed with respect to those found in previous studies for many other GCs. Our findings, therefore, seem contradictory to the current scenario for the formation of multiple stellar populations, but mass segregation acting on the two subpopulations might be a possible solution to explain this reversed radial trend.

  14. Multi-objective PSO based optimal placement of solar power DG in radial distribution system

    Directory of Open Access Journals (Sweden)

    Mahesh Kumar

    2017-06-01

    Full Text Available Ever increasing trend of electricity demand, fossil fuel depletion and environmental issues request the integration of renewable energy into the distribution system. The optimal planning of renewable distributed generation (DG is much essential for ensuring maximum benefits. Hence, this paper proposes the optimal placement of probabilistic based solar power DG into the distribution system. The two objective functions such as power loss reduction and voltage stability index improvement are optimized. The power balance and voltage limits are kept as constraints of the problem. The non-sorting pare to-front based multi-objective particle swarm optimization (MOPSO technique is proposed on standard IEEE 33 radial distribution test system.

  15. Design, construction and mechanical optimisation process of electrode with radial current flow in the scala tympani.

    Science.gov (United States)

    Deman, P R; Kaiser, T M; Dirckx, J J; Offeciers, F E; Peeters, S A

    2003-09-30

    A 48 contact cochlear implant electrode has been constructed for electrical stimulation of the auditory nerve. The stimulating contacts of this electrode are organised in two layers: 31 contacts on the upper surface directed towards the habenula perforata and 17 contacts connected together as one longitudinal contact on the underside. The design of the electrode carrier aims to make radial current flow possible in the cochlea. The mechanical structure of the newly designed electrode was optimised to obtain maximal insertion depth. Electrode insertion tests were performed in a transparent acrylic model of the human cochlea.

  16. Inertia effects in the laminar radial flow of a power law fluid with an electromagnetic field

    International Nuclear Information System (INIS)

    Chen, C.-K.; Chen, K.-H.; Wu, C.-Y.

    1984-01-01

    An approximate study of the pressure distribution for the radial flow of a non-newtonian (power law) fluid between two parallel disks in the presence of an axial electrical field is obtained by using the momentum and energy integral methods. For a non-newtonian fluid it is shown that the inertia effect must be considered to be significant for the pressure distribution, especially for the power law fluids with n >= 1. Furthermore, it is seen that the inertia effect will also lower the load capacity of the disks. (Auth.)

  17. Developing equivalent circuits for radial distribution networks

    Energy Technology Data Exchange (ETDEWEB)

    Prada, Ricardo; Coelho, Agnelo; Rodrigues, Anselmo [Catholic University of Rio de Janeiro (PUC-Rio), RJ (Brazil). Dept. of Electrical Engineering], Emails: prada@ele.puc-rio.br, agnelo@ele.puc-rio.br, nebulok_99@yahoo.com; Silva, Maria da Guia da [Federal University of Maranhao, Sao Luiz, MA (Brazil). Dept. of Electrical Engineering

    2009-07-01

    This paper presents a method for evaluating External Equivalent in Electric Distribution Networks (EDN).The proposed method has as its main objectives the reduction of the computational costs in distribution network reconfiguration, investigation of the optimal allocation of banks of capacitors, investigation of the allocation of distributed generation, etc. In these sorts of problems a large number of alternative projects must be assessed in order to identify the optimal solution. The optimal solution comes up with the voltage level in the load points within specified limits. Consequently, the EDN must retain the external network load points but without major increasing in the dimension of the equivalent circuit. The proposed method has been tested and validated in a substation of the Electricity Utility of Maranhao - CEMAR, in Brazil. (author)

  18. NEW RADIAL ABUNDANCE GRADIENTS FOR NGC 628 AND NGC 2403

    Energy Technology Data Exchange (ETDEWEB)

    Berg, Danielle A.; Skillman, Evan D. [Department of Astronomy, University of Minnesota, 116 Church St. SE, Minneapolis, MN 55455 (United States); Croxall, Kevin V. [Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States); Marble, Andrew R. [National Solar Observatory, 950 N Cherry Avenue, Tucson, AZ 85719 (United States); Smith, J. D. [Ritter Astrophysical Observatory, University of Toledo, Toledo, OH 43606 (United States); Gordon, Karl [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Kennicutt, Robert C. Jr. [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom); Garnett, Donald R., E-mail: berg@astro.umn.edu, E-mail: skillman@astro.umn.edu, E-mail: croxall.5@osu.edu, E-mail: amarble@nso.edu, E-mail: jd.smith@utoledo.edu, E-mail: kgordon@stsci.edu, E-mail: robk@ast.cam.ac.uk

    2013-10-01

    Motivated by recent interstellar medium studies, we present high quality MMT and Gemini spectroscopic observations of H II regions in the nearby spiral galaxies NGC 628 and NGC 2403 in order to measure their chemical abundance gradients. Using long-slit and multi-object mask optical spectroscopy, we obtained measurements of the temperature sensitive auroral lines [O III] λ4363 and/or [N II] λ5755 at a strength of 4σ or greater in 11 H II regions in NGC 628 and 7 regions in NGC 2403. These observations allow us, for the first time, to derive an oxygen abundance gradient in NGC 628 based solely on 'direct' oxygen abundances of H II regions: 12 + log(O/H) = (8.43 ± 0.03) + (–0.017 ± 0.002) × R{sub g} (dex kpc{sup –1}), with a dispersion in log(O/H) of σ = 0.10 dex, from 14 regions with a radial coverage of ∼2-19 kpc. This is a significantly shallower slope than found by previous 'strong-line' abundance studies. In NGC 2403, we derive an oxygen abundance gradient of 12 + log(O/H) = (8.48 ± 0.04) + (–0.032 ± 0.007)× R{sub g} (dex kpc{sup –1}), with a dispersion in log(O/H) of σ = 0.07 dex, from seven H II with a radial coverage of ∼1-10 kpc. Additionally, we measure the N, S, Ne, and Ar abundances. We find the N/O ratio decreases with increasing radius for the inner disk, but reaches a plateau past R{sub 25} in NGC 628. NGC 2403 also has a negative N/O gradient with radius, but we do not sample the outer disk of the galaxy past R{sub 25} and so do not see evidence for a plateau. This bi-modal pattern measured for NGC 628 indicates dominant contributions from secondary nitrogen inside of the R{sub 25} transition and dominantly primary nitrogen farther out. As expected for α-process elements, S/O, Ne/O, and Ar/O are consistent with constant values over a range in oxygen abundance.

  19. Magneto-Electric Dipole Antenna Arrays

    OpenAIRE

    Gupta, Shulabh; Jiang, Li Jun; Caloz, Christophe

    2014-01-01

    A planar magneto-electric (ME) dipole antenna array is proposed and demonstrated by both full-wave analysis and experiments. The proposed structure leverages the infinite wavelength propagation characteristic of composite right/left-handed (CRLH) transmission lines to form high-gain magnetic radiators combined with radial conventional electric radiators, where the overall structure is excited by a single differential feed. The traveling-wave type nature of the proposed ME-dipole antenna enabl...

  20. Radial thermal diffusivity of toroidal plasma affected by resonant magnetic perturbations

    International Nuclear Information System (INIS)

    Kanno, Ryutaro; Nunami, Masanori; Satake, Shinsuke; Takamaru, Hisanori; Okamoto, Masao

    2012-04-01

    We investigate how the radial thermal diffusivity of an axisymmetric toroidal plasma is modified by effect of resonant magnetic perturbations (RMPs), using a drift kinetic simulation code for calculating the thermal diffusivity in the perturbed region. The perturbed region is assumed to be generated on and around the resonance surfaces, and is wedged in between the regular closed magnetic surfaces. It has been found that the radial thermal diffusivity χ r in the perturbed region is represented as χ r = χ r (0) {1 + c r parallel 2 >}. Here r parallel 2 > 1/2 is the strength of the RMPs in the radial directions, means the flux surface average defined by the unperturbed (i.e., original) magnetic field, χ r (0) is the neoclassical thermal diffusivity, and c is a positive coefficient. In this paper, dependence of the coefficient c on parameters of the toroidal plasma is studied in results given by the δ f simulation code solving the drift kinetic equation under an assumption of zero electric field. We find that the dependence of c is given as c ∝ ω b /ν eff m in the low collisionality regime ν eff b , where ν eff is the effective collision frequency, ω b is the bounce frequency and m is the particle mass. In case of ν eff > ω b , the thermal diffusivity χ r evaluated by the simulations becomes close to the neoclassical thermal diffusivity χ r (0) . (author)

  1. Hall devices improve electric motor efficiency

    Science.gov (United States)

    Haeussermann, W.

    1979-01-01

    Efficiency of electric motors and generators is reduced by radial magnetic forces created by symmetric fields within device. Forces are sensed and counteracted by Hall devices on excitation or control windings. Hall generators directly measure and provide compensating control of anu asymmetry, eliminating additional measurements needed for calibration feedback control loop.

  2. RADIAL VELOCITY MONITORING OF KEPLER HEARTBEAT STARS

    Energy Technology Data Exchange (ETDEWEB)

    Shporer, Avi [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Fuller, Jim [TAPIR, Walter Burke Institute for Theoretical Physics, Mailcode 350-17, Caltech, Pasadena, CA 91125 (United States); Isaacson, Howard [Department of Astronomy, University of California, Berkeley CA 94720 (United States); Hambleton, Kelly; Prša, Andrej [Department of Astrophysics and Planetary Science, Villanova University, 800 East Lancaster Avenue, Villanova, PA 19085 (United States); Thompson, Susan E. [NASA Ames Research Center, Moffett Field, CA 94035 (United States); Kurtz, Donald W. [Jeremiah Horrocks Institute, University of Central Lancashire, Preston, PR1 2HE (United Kingdom); Howard, Andrew W. [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); O’Leary, Ryan M. [JILA, University of Colorado and NIST, 440 UCB, Boulder, 80309-0440 (United States)

    2016-09-20

    Heartbeat stars (HB stars) are a class of eccentric binary stars with close periastron passages. The characteristic photometric HB signal evident in their light curves is produced by a combination of tidal distortion, heating, and Doppler boosting near orbital periastron. Many HB stars continue to oscillate after periastron and along the entire orbit, indicative of the tidal excitation of oscillation modes within one or both stars. These systems are among the most eccentric binaries known, and they constitute astrophysical laboratories for the study of tidal effects. We have undertaken a radial velocity (RV) monitoring campaign of Kepler HB stars in order to measure their orbits. We present our first results here, including a sample of 22 Kepler HB systems, where for 19 of them we obtained the Keplerian orbit and for 3 other systems we did not detect a statistically significant RV variability. Results presented here are based on 218 spectra obtained with the Keck/HIRES spectrograph during the 2015 Kepler observing season, and they have allowed us to obtain the largest sample of HB stars with orbits measured using a single instrument, which roughly doubles the number of HB stars with an RV measured orbit. The 19 systems measured here have orbital periods from 7 to 90 days and eccentricities from 0.2 to 0.9. We show that HB stars draw the upper envelope of the eccentricity–period distribution. Therefore, HB stars likely represent a population of stars currently undergoing high eccentricity migration via tidal orbital circularization, and they will allow for new tests of high eccentricity migration theories.

  3. Scaling laws for radial foil bearings

    Science.gov (United States)

    Honavara Prasad, Srikanth

    The effects of fluid pressurization, structural deformation of the compliant members and heat generation in foil bearings make the design and analysis of foil bearings very complicated. The complex fluid-structural-thermal interactions in foil bearings also make modeling efforts challenging because these phenomena are governed by highly non-linear partial differential equations. Consequently, comparison of various bearing designs require detailed calculation of the flow fields (velocities, pressures), bump deflections (structural compliance) and heat transfer phenomena (viscous dissipation in the fluid, frictional heating, temperature profile etc.,) resulting in extensive computational effort (time/hardware). To obviate rigorous computations and aid in feasibility assessments of foil bearings of various sizes, NASA developed the "rule of thumb" design guidelines for estimation of journal bearing load capacity. The guidelines are based on extensive experimental data. The goal of the current work is the development of scaling laws for radial foil bearings to establish an analytical "rule of thumb" for bearing clearance and bump stiffness. The use of scale invariant Reynolds equation and experimentally observed NASA "rule of thumb" yield scale factors which can be deduced from first principles. Power-law relationships between: a. Bearing clearance and bearing radius, and b. bump stiffness and bearing radius, are obtained. The clearance and bump stiffness values obtained from scaling laws are used as inputs for Orbit simulation to study various cases. As the clearance of the bearing reaches the dimensions of the material surface roughness, asperity contact breaks the fluid film which results in wear. Similarly, as the rotor diameter increases (requiring larger bearing diameters), the load capacity of the fluid film should increase to prevent dry rubbing. This imposes limits on the size of the rotor diameter and consequently bearing diameter. Therefore, this thesis aims

  4. RADIAL VELOCITY MONITORING OF KEPLER HEARTBEAT STARS

    International Nuclear Information System (INIS)

    Shporer, Avi; Fuller, Jim; Isaacson, Howard; Hambleton, Kelly; Prša, Andrej; Thompson, Susan E.; Kurtz, Donald W.; Howard, Andrew W.; O’Leary, Ryan M.

    2016-01-01

    Heartbeat stars (HB stars) are a class of eccentric binary stars with close periastron passages. The characteristic photometric HB signal evident in their light curves is produced by a combination of tidal distortion, heating, and Doppler boosting near orbital periastron. Many HB stars continue to oscillate after periastron and along the entire orbit, indicative of the tidal excitation of oscillation modes within one or both stars. These systems are among the most eccentric binaries known, and they constitute astrophysical laboratories for the study of tidal effects. We have undertaken a radial velocity (RV) monitoring campaign of Kepler HB stars in order to measure their orbits. We present our first results here, including a sample of 22 Kepler HB systems, where for 19 of them we obtained the Keplerian orbit and for 3 other systems we did not detect a statistically significant RV variability. Results presented here are based on 218 spectra obtained with the Keck/HIRES spectrograph during the 2015 Kepler observing season, and they have allowed us to obtain the largest sample of HB stars with orbits measured using a single instrument, which roughly doubles the number of HB stars with an RV measured orbit. The 19 systems measured here have orbital periods from 7 to 90 days and eccentricities from 0.2 to 0.9. We show that HB stars draw the upper envelope of the eccentricity–period distribution. Therefore, HB stars likely represent a population of stars currently undergoing high eccentricity migration via tidal orbital circularization, and they will allow for new tests of high eccentricity migration theories.

  5. Effects of the Electric Field on the Direct Loss Asymmetries on TJ-II

    International Nuclear Information System (INIS)

    Guasp, J.

    1997-01-01

    The effects of the radial electric fields upon the direct loss asymmetries have been studied for low energy (0.1-1keV)ions. The analysis shows the permanence of the predominant downwards asymmetry that is only slightly modified in the poloidal rotation direction for moderate electric fields. In TJ-II this poloidal rotation is directed towards decreasing poloidal angles for positive (outward) electric fields and the ions drift along the same direction. Nevertheless for very strong fields the lost particles concentrate in the extreme plasma periphery (at the same time that the rate loss decreases strongly) and have no time, any more, to feel the poloidal rotation before escaping. The gaps between the TF coils receive the most of the losses. On the Vacuum Vessel the losses have a very strong concentration along the Hard Core, in particular on the PLT-2 plane plate (the one that is placed down at Phi=0 degree centigree) and a moderate preference for the 2''nd toroidal octant of each period. The poloidal rotation is much less visible than on the plasma border. The resulting power loads are small. (Author)

  6. Fluid simulation of the phase-shift effect in hydrogen capacitively coupled plasmas: II. Radial uniformity of the plasma characteristics

    International Nuclear Information System (INIS)

    Zhang Yuru; Xu Xiang; Wang Younian; Bogaerts, Annemie

    2012-01-01

    . The calculation results illustrate that the radial uniformity of the various plasma characteristics is strongly dependent on the applied frequency and the phase shift between both power sources, which is important to realize, for controlling the uniformity of the plasma etch and deposition processes. (paper)

  7. Radial head fracture associated with posterior interosseous nerve injury

    Directory of Open Access Journals (Sweden)

    Bernardo Barcellos Terra

    Full Text Available ABSTRACT Fractures of the radial head and radial neck correspond to 1.7-5.4% of all fractures and approximately 30% may present associated injuries. In the literature, there are few reports of radial head fracture with posterior interosseous nerve injury. This study aimed to report a case of radial head fracture associated with posterior interosseous nerve injury. CASE REPORT: A male patient, aged 42 years, sought medical care after falling from a skateboard. The patient related pain and limitation of movement in the right elbow and difficulty to extend the fingers of the right hand. During physical examination, thumb and fingers extension deficit was observed. The wrist extension showed a slight radial deviation. After imaging, it became evident that the patient had a fracture of the radial head that was classified as grade III in the Mason classification. The patient underwent fracture fixation; at the first postoperative day, thumb and fingers extension was observed. Although rare, posterior interosseous nerve branch injury may be associated with radial head fractures. In the present case, the authors believe that neuropraxia occurred as a result of the fracture hematoma and edema.

  8. Designing asymmetric multiferroics with strong magnetoelectric coupling

    Science.gov (United States)

    Lu, Xuezeng; Xiang, Hongjun; Rondinelli, James; Materials Theory; Design Group Team

    2015-03-01

    Multiferroics offer exciting opportunities for electric-field control of magnetism. Single-phase multiferroics suitable for such applications at room temperature need much more study. Here, we propose the concept of an alternative type of multiferroics, namely, the ``asymmetric multiferroic.'' In asymmetric multiferroics, two locally stable ferroelectric states are not symmetrically equivalent, leading to different magnetic properties between these two states. Furthermore, we predict from first principles that a Fe-Cr-Mo superlattice with the LiNbO3-type structure is such an asymmetric multiferroic. The strong ferrimagnetism, high ferroelectric polarization, and significant dependence of the magnetic transition temperature on polarization make this asymmetric multiferroic an ideal candidate for realizing electric-field control of magnetism at room temperature. Our study suggests that the asymmetric multiferroic may provide an alternative playground for voltage control of magnetism and find its applications in spintronics and quantum computing.

  9. Fully developed liquid-metal flow in multiple rectangular ducts in a strong uniform magnetic field

    International Nuclear Information System (INIS)

    Molokov, S.

    1993-01-01

    Fully developed liquid-metal flow in a straight rectangular duct with thin conducting walls is investigated. The duct is divided into a number of rectangular channels by electrically conducting dividing walls. A strong uniform magnetic field is applied parallel to the outer side walls and dividing walls and perpendicular to the top and the bottom walls. The analysis of the flow is performed by means of matched asymptotics at large values of the Hartmann number M. The asymptotic solution obtained is valid for arbitrary wall conductance ratio of the side walls and dividing walls, provided the top and bottom walls are much better conductors than the Hartmann layers. The influence of the Hartmann number, wall conductance ratio, number of channels and duct geometry on pressure losses and flow distribution is investigated. If the Hartmann number is high, the volume flux is carried by the core, occupying the bulk of the fluid and by thin layers with thickness of order M -1/2 . In some of the layers, however, the flow is reversed. As the number of channels increases the flow in the channels close to the centre approaches a Hartmann-type flow with no jets at the side walls. Estimation of pressure-drop increase in radial ducts of a self-cooled liquid-metal blanket with respect to flow in a single duct with walls of the same wall conductance ratio gives an upper limit of 30%. (author). 13 refs., 10 figs., 1 tab

  10. Optimum topology for radial networks by using evolutionary computer programming; Topologia optima de redes radiais utilizando programacao evolucionaria

    Energy Technology Data Exchange (ETDEWEB)

    Pinto, Joao Luis [Instituto de Engenhariade Sistemas e Computadores (INESC), Porto (Portugal). E-mail: jpinto@duque.inescn.pt; Proenca, Luis Miguel [Instituto Superior de Linguas e Administracao (ISLA), Gaia (Portugal). E-mail: lproenca@inescn.pt

    1999-07-01

    This paper describes the using of Evolutionary Programming techniques for determination of the radial electric network topology, considering investment costs and losses. The work aims to demonstrate the particular easiness of coding and implementation and the parallelism implicit to the method as well, giving outstanding performance levels. As test example, a 43 bars and 75 alternative lines network has been used by describing an implementation of the algorithm in an Object Oriented platform.

  11. Radial and axial compression of pure electron

    International Nuclear Information System (INIS)

    Park, Y.; Soga, Y.; Mihara, Y.; Takeda, M.; Kamada, K.

    2013-01-01

    Experimental studies are carried out on compression of the density distribution of a pure electron plasma confined in a Malmberg-Penning Trap in Kanazawa University. More than six times increase of the on-axis density is observed under application of an external rotating electric field that couples to low-order Trivelpiece-Gould modes. Axial compression of the density distribution with the axial length of a factor of two is achieved by controlling the confining potential at both ends of the plasma. Substantial increase of the axial kinetic energy is observed during the axial compression. (author)

  12. Control of radial propagation and polarity in a plasma jet in surrounding Ar

    KAUST Repository

    Gong, W.

    2018-01-08

    In recent years, the use of shielding gas to prevent the diffusion of the ambient air, particularly oxygen and nitrogen species, into the effluent of the atmospheric pressure plasma jet, and thus control the nature of chemical species used in the plasma treatment has increased. In this paper, the radial propagation of a plasma jet in ambient Ar is examined to find the key determinants of the polarity of plasma jets. The dynamics of the discharge reveal that the radial diffusion discharge is a special phenomenon observed only at the falling edge of the pulses. The radial transport of electrons, which is driven by the radial component of the applied electric field at the falling edge of the pulse, is shown to play an important role in increasing the seed electron density in the surrounding Ar. This result suggests a method to provide seed electrons at atmospheric pressure with a negative discharge. The polarity of the plasma jet is found to be determined by the pulse width rather than the polarity of the applied voltage, as it dictates the relative difference in the intensity of the two discharges in a single pulse, where the stronger discharge in a pulse dominates the behavior of the plasma jet. Accordingly, a method to control the polarity of a plasma jet through varying the pulse width is developed. Since plasma jets of different polarities differ remarkably in terms of their characteristics, the method to control the polarity reported in this paper will be of use for such applications as plasma-enhanced processing of materials and plasma biomedicine.

  13. Control of radial propagation and polarity in a plasma jet in surrounding Ar

    Science.gov (United States)

    Gong, W.; Yue, Y.; Ma, F.; Yu, F.; Wan, J.; Nie, L.; Bazaka, K.; Xian, Y.; Lu, X.; Ostrikov, K.

    2018-01-01

    In recent years, the use of shielding gas to prevent the diffusion of the ambient air, particularly oxygen and nitrogen species, into the effluent of the atmospheric pressure plasma jet, and thus control the nature of chemical species used in the plasma treatment has increased. In this paper, the radial propagation of a plasma jet in ambient Ar is examined to find the key determinants of the polarity of plasma jets. The dynamics of the discharge reveal that the radial diffusion discharge is a special phenomenon observed only at the falling edge of the pulses. The radial transport of electrons, which is driven by the radial component of the applied electric field at the falling edge of the pulse, is shown to play an important role in increasing the seed electron density in the surrounding Ar. This result suggests a method to provide seed electrons at atmospheric pressure with a negative discharge. The polarity of the plasma jet is found to be determined by the pulse width rather than the polarity of the applied voltage, as it dictates the relative difference in the intensity of the two discharges in a single pulse, where the stronger discharge in a pulse dominates the behavior of the plasma jet. Accordingly, a method to control the polarity of a plasma jet through varying the pulse width is developed. Since plasma jets of different polarities differ remarkably in terms of their characteristics, the method to control the polarity reported in this paper will be of use for such applications as plasma-enhanced processing of materials and plasma biomedicine.

  14. Stellar Angular Momentum Distributions and Preferential Radial Migration

    Science.gov (United States)

    Wyse, Rosemary; Daniel, Kathryne J.

    2018-04-01

    I will present some results from our recent investigations into the efficiency of radial migration in stellar disks of differing angular momentum distributions, within a given adopted 2D spiral disk potential. We apply to our models an analytic criterion that determines whether or not individual stars are in orbits that could lead to radial migration around the corotation resonance. We couch our results in terms of the local stellar velocity dispersion and find that the fraction of stars that could migrate radially decreases as the velocity dispersion increases. I will discuss implications and comparisons with the results of other approaches.

  15. Research on Radial Vibration of a Circular Plate

    Directory of Open Access Journals (Sweden)

    Wei Liu

    2016-01-01

    Full Text Available Radial vibration of the circular plate is presented using wave propagation approach and classical method containing Bessel solution and Hankel solution for calculating the natural frequency theoretically. In cylindrical coordinate system, in order to obtain natural frequency, propagation and reflection matrices are deduced at the boundaries of free-free, fixed-fixed, and fixed-free using wave propagation approach. Furthermore, radial phononic crystal is constructed by connecting two materials periodically for the analysis of band phenomenon. Also, Finite Element Simulation (FEM is adopted to verify the theoretical results. Finally, the radial and piezoelectric effects on the band are also discussed.

  16. Strong piezoelectricity in bioinspired peptide nanotubes.

    Science.gov (United States)

    Kholkin, Andrei; Amdursky, Nadav; Bdikin, Igor; Gazit, Ehud; Rosenman, Gil

    2010-02-23

    We show anomalously strong shear piezoelectric activity in self-assembled diphenylalanine peptide nanotubes (PNTs), indicating electric polarization directed along the tube axis. Comparison with well-known piezoelectric LiNbO(3) and lateral signal calibration yields sufficiently high effective piezoelectric coefficient values of at least 60 pm/V (shear response for tubes of approximately 200 nm in diameter). PNTs demonstrate linear deformation without irreversible degradation in a broad range of driving voltages. The results open up a wide avenue for developing new generations of "green" piezoelectric materials and piezonanodevices based on bioactive tubular nanostructures potentially compatible with human tissue.

  17. Strong spin-photon coupling in silicon

    Science.gov (United States)

    Samkharadze, N.; Zheng, G.; Kalhor, N.; Brousse, D.; Sammak, A.; Mendes, U. C.; Blais, A.; Scappucci, G.; Vandersypen, L. M. K.

    2018-03-01

    Long coherence times of single spins in silicon quantum dots make these systems highly attractive for quantum computation, but how to scale up spin qubit systems remains an open question. As a first step to address this issue, we demonstrate the strong coupling of a single electron spin and a single microwave photon. The electron spin is trapped in a silicon double quantum dot, and the microwave photon is stored in an on-chip high-impedance superconducting resonator. The electric field component of the cavity photon couples directly to the charge dipole of the electron in the double dot, and indirectly to the electron spin, through a strong local magnetic field gradient from a nearby micromagnet. Our results provide a route to realizing large networks of quantum dot–based spin qubit registers.

  18. Granular Corneal Dystrophy Manifesting after Radial Keratotomy

    Directory of Open Access Journals (Sweden)

    Sepehr Feizi

    2008-12-01

    Full Text Available

    PURPOSE: To report manifestation of granular corneal dystrophy after radial keratotomy (RK. CASE REPORT: A 32-year-old man presented with white radial lines in both corneas. He had undergone uncomplicated RK in both eyes 8 years ago. Preoperative refraction had been OD: -3.5 -0.75@180 and OS: -3.0 -0.5@175. Uncorrected visual acuity was OD: 8/10 and OS: 7/10; best corrected visual acuity was 9/10 in both eyes with OD: -0.5 -0.5@60 and OS: -0.75 -0.5@80. Slit lamp examination revealed discrete well-demarcated whitish lesions with clear intervening stroma in the central anterior cornea consistent with granular dystrophy. Similar opacities were present within the RK incisions. CONCLUSION: Granular dystrophy deposits may appear within RK incisions besides other previously reported locations.

  1. Limitations of the strong field approximation in ionization of the hydrogen atom by ultrashort pulses

    International Nuclear Information System (INIS)

    Arbo, D.G.; Toekesi, K.; Miraglia, J.E.; FCEN, University of Buenos Aires

    2008-01-01

    Complete text of publication follows. We presented a theoretical study of the ionization of hydrogen atoms as a result of the interaction with an ultrashort external electric field. Doubly-differential momentum distributions and angular momentum distributions of ejected electrons calculated in the framework of the Coulomb-Volkov and strong field approximations, as well as classical calculations are compared with the exact solution of the time dependent Schroedinger equation. We have shown that the Coulomb-Volkov approximation (CVA) describes the quantum atomic ionization probabilities exactly when the external field is described by a sudden momentum transfer [1]. The velocity distribution of emitted electrons right after ionization by a sudden momentum transfer is given through the strong field approximation (SFA) within both the CVA and CTMC methods. In this case, the classical and quantum time dependent evolutions of an atom subject to a sudden momentum transfer are identical. The difference between the classical and quantum final momentum distributions resides in the time evolution of the escaping electron under the subsequent action of the Coulomb field. Furthermore, classical mechanics is incapable of reproducing the quantum angular momentum distribution due to the improper initial radial distribution used in the CTMC calculations, i.e., the microcanonical ensemble. We find that in the limit of high momentum transfer, based on the SFA, there is a direct relation between the cylindrical radial distribution dP/dρ and the final angular momentum distribution dP/dL. This leads to a close analytical expression for the partial wave populations (dP/dL) SFA-Q given by dP SFA-Q / dL = 4Z 3 L 2 / (Δp) 3 K 1 (2ZL/Δp) which, together with the prescription L = l + 1/2, reproduces quite accurately the quantum (CVA) results. Considering the inverse problem, knowing the final angular momentum distribution can lead to the inference of the initial probability distribution

  2. relay coordination in the protection of radially-connected power

    African Journals Online (AJOL)

    ... PROTECTION OF. RADIALLY-CONNECTED POWER SYSTEM NETWORK ... Protective relays detect intolerable or unwanted conditions within an assigned area, and then trip or open one ... time, and current transformer ratio errors. 2.2.1.

  3. Photoelectric Radial Velocities, Paper XVIII Spectroscopic Orbits for ...

    Indian Academy of Sciences (India)

    The fundamental origin of the work presented here rests with the radial-velocity spectrometer that .... surfaces inevitably degrade rather rapidly in the environment in which they are called ...... are not safe to incorporate in the data set here.

  4. Endoscopic Radial Artery Harvest for Coronary Artery Bypass Surgery

    Directory of Open Access Journals (Sweden)

    Kuan-Ming Chiu

    2006-01-01

    Conclusion: Endoscopic harvest of the radial artery is technically demanding, but excellent results can be achieved. The endoscopic approach can provide suitable conduits in a less invasive way than the open harvest technique.

  5. Analyzing radial acceleration with a smartphone acceleration sensor

    Science.gov (United States)

    Vogt, Patrik; Kuhn, Jochen

    2013-03-01

    This paper continues the sequence of experiments using the acceleration sensor of smartphones (for description of the function and the use of the acceleration sensor, see Ref. 1) within this column, in this case for analyzing the radial acceleration.

  6. A synthesis of radial growth patterns preceding tree mortality

    Science.gov (United States)

    Cailleret, Maxime; Jansen, Steven; Robert, Elisabeth M.R.; Desoto, Lucia; Aakala, Tuomas; Antos, Joseph A.; Beikircher, Barbara; Bigler, Christof; Bugmann, Harald; Caccianiga, Marco; Cada, Vojtech; Camarero, Jesus J.; Cherubini, Paolo; Cochard, Herve; Coyea, Marie R.; Cufar, Katarina; Das, Adrian J.; Davi, Hendrik; Delzon, Sylvain; Dorman, Michael; Gea-Izquierdo, Guillermo; Gillner, Sten; Haavik, Laurel J.; Hartmann, Henrik; Heres, Ana-Maria; Hultine, Kevin R.; Janda, Pavel; Kane, Jeffrey M.; Kharuk, Vyacheslav I.; Kitzberger, Thomas; Klein, Tamir; Kramer, Koen; Lens, Frederic; Levanic, Tom; Calderon, Juan C. Linares; Lloret, Francisco; Lobo-Do-Vale, Raquel; Lombardi, Fabio; Lopez Rodriguez, Rosana; Makinen, Harri; Mayr, Stefan; Meszaros, IIona; Metsaranta, Juha M.; Minunno, Francesco; Oberhuber, Walter; Papadopoulos, Andreas; Peltoniemi, Mikko; Petritan, Any M.; Rohner, Brigitte; Sanguesa-Barreda, Gabriel; Sarris, Dimitrios; Smith, Jeremy M.; Stan, Amanda B.; Sterck, Frank; Stojanovic, Dejan B.; Suarez, Maria L.; Svoboda, Miroslav; Tognetti, Roberto; Torres-Ruiz, Jose M.; Trotsiuk, Volodymyr; Villalba, Ricardo; Vodde, Floor; Westwood, Alana R.; Wyckoff, Peter H.; Zafirov, Nikolay; Martinez-Vilalta, Jordi

    2017-01-01

    Tree mortality is a key factor influencing forest functions and dynamics, but our understanding of the mechanisms leading to mortality and the associated changes in tree growth rates are still limited. We compiled a new pan-continental tree-ring width database from sites where both dead and living trees were sampled (2970 dead and 4224 living trees from 190 sites, including 36 species), and compared early and recent growth rates between trees that died and those that survived a given mortality event. We observed a decrease in radial growth before death in ca. 84% of the mortality events. The extent and duration of these reductions were highly variable (1–100 years in 96% of events) due to the complex interactions among study species and the source(s) of mortality. Strong and long-lasting declines were found for gymnosperms, shade- and drought-tolerant species, and trees that died from competition. Angiosperms and trees that died due to biotic attacks (especially bark-beetles) typically showed relatively small and short-term growth reductions. Our analysis did not highlight any universal trade-off between early growth and tree longevity within a species, although this result may also reflect high variability in sampling design among sites. The intersite and interspecific variability in growth patterns before mortality provides valuable information on the nature of the mortality process, which is consistent with our understanding of the physiological mechanisms leading to mortality. Abrupt changes in growth immediately before death can be associated with generalized hydraulic failure and/or bark-beetle attack, while long-term decrease in growth may be associated with a gradual decline in hydraulic performance coupled with depletion in carbon reserves. Our results imply that growth-based mortality algorithms may be a powerful tool for predicting gymnosperm mortality induced by chronic stress, but not necessarily so for angiosperms and in case of intense drought or

  7. MODELING OF OPERATION OF COAXIAL-LINEAR MOTORS WITH AXIAL AND RADIAL DIRECTIONS OF MAGNETIZATION OF PERMANENT MAGNETS IN DYNAMIC MODE

    Directory of Open Access Journals (Sweden)

    G.M. Golenkov

    2014-12-01

    Full Text Available Theoretical and experimental investigations of the amplitude, phase and inertia-power frequency characteristics of two types of coaxial-linear electric motors of back-and-forth motion with permanent magnets, which magnetization vector is directed axially and radially relative to the axis of the runner are carried out. The comparative analysis of characteristics of these motors is presented.

  8. Electricity Theory

    International Nuclear Information System (INIS)

    Gong, Ha Soung

    2006-12-01

    The text book composed of five parts, which are summary of this book, arrangement of electricity theory including electricity nad magnetism, a direct current, and alternating current. It has two dictionary electricity terms for a synonym. The last is an appendix. It is for preparing for test of officer, electricity engineer and fire fighting engineer.

  9. Endoscopic versus open radial artery harvest and mammario-radial versus aorto-radial grafting in patients undergoing coronary artery bypass surgery

    DEFF Research Database (Denmark)

    Carranza, Christian L; Ballegaard, Martin; Werner, Mads U

    2014-01-01

    the postoperative complications will be registered, and we will evaluate muscular function, scar appearance, vascular supply to the hand, and the graft patency including the patency of the central radial artery anastomosis. A patency evaluation by multi-slice computer tomography will be done at one year...... to aorto-radial revascularisation techniques but this objective is exploratory. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT01848886.Danish Ethics committee number: H-3-2012-116.Danish Data Protection Agency: 2007-58-0015/jr.n:30-0838....

  10. Anterior transposition of the radial nerve--a cadaveric study.

    Science.gov (United States)

    Yakkanti, Madhusudhan R; Roberts, Craig S; Murphy, Joshua; Acland, Robert D

    2008-01-01

    The radial nerve is at risk during the posterior plating of the humerus. The purpose of this anatomic study was to assess the extent of radial nerve dissection required for anterior transposition through the fracture site (transfracture anterior transposition). A cadaver study was conducted approaching the humerus by a posterior midline incision. The extent of dissection of the nerve necessary for plate fixation of the humerus fracture was measured. An osteotomy was created to model a humeral shaft fracture at the spiral groove (OTA classification 12-A2, 12-A3). The radial nerve was then transposed anterior to the humeral shaft through the fracture site. The additional dissection of the radial nerve and the extent of release of soft tissue from the humerus shaft to achieve the transposition were measured. Plating required a dissection of the radial nerve 1.78 cm proximal and 2.13 cm distal to the spiral groove. Transfracture anterior transposition of the radial nerve required an average dissection of 2.24 cm proximal and 2.68 cm distal to the spiral groove. The lateral intermuscular septum had to be released for 2.21 cm on the distal fragment to maintain laxity of the transposed nerve. Transfracture anterior transposition of the radial nerve before plating is feasible with dissection proximal and distal to the spiral groove and elevation of the lateral intermuscular septum. Potential clinical advantages of this technique include enhanced fracture site visualization, application of broader plates, and protection of the radial nerve during the internal fixation.

  11. Radial-piston pump for drive of test machines

    Science.gov (United States)

    Nizhegorodov, A. I.; Gavrilin, A. N.; Moyzes, B. B.; Cherkasov, A. I.; Zharkevich, O. M.; Zhetessova, G. S.; Savelyeva, N. A.

    2018-01-01

    The article reviews the development of radial-piston pump with phase control and alternating-flow mode for seismic-testing platforms and other test machines. The prospects for use of the developed device are proved. It is noted that the method of frequency modulation with the detection of the natural frequencies is easily realized by using the radial-piston pump. The prospects of further research are given proof.

  12. Radially Polarized Conical Beam from an Embedded Etched Fiber

    OpenAIRE

    Kalaidji , D.; Spajer , M.; Marthouret , N.; Grosjean , T.

    2009-01-01

    International audience; We propose a method for producing a conical beam based on the lateral refraction of the TM01 mode from a two-mode fiber after chemical etching of the cladding, and for controlling its radial polarization. The whole power of the guided mode is transferred to the refracted beam with low diffraction. Polarization control by a series of azimuthal detectors and a stress controller affords the transmission of a stabilized radial polarization through an optical fiber. A solid...

  13. Luxation of the radial carpal bone in a cat

    International Nuclear Information System (INIS)

    Pitcher, G.D.C.

    1996-01-01

    A case of radial carpal bone luxation in the cat and its management is described. Open reduction was performed and surgically maintained, in combination with repair of rupture of the short radial collateral ligament and joint capsule. The carpus was supported for one month following surgery by application of transarticular external fixation. Four months after treatment the cat was sound, despite evidence of degenerative joint disease. The mechanism of luxation appears to be analogous to that seen in the dog

  14. Superfluid quenching of the moment of inertia in a strongly interacting Fermi gas

    Science.gov (United States)

    Riedl, S.; Sánchez Guajardo, E. R.; Kohstall, C.; Hecker Denschlag, J.; Grimm, R.

    2011-03-01

    We report on the observation of a quenched moment of inertia resulting from superfluidity in a strongly interacting Fermi gas. Our method is based on setting the hydrodynamic gas in slow rotation and determining its angular momentum by detecting the precession of a radial quadrupole excitation. The measurements distinguish between the superfluid and collisional origins of hydrodynamic behavior, and show the phase transition.

  15. Motion of guiding center drift atoms in the electric and magnetic field of a Penning trap

    International Nuclear Information System (INIS)

    Kuzmin, S.G.; O'Neil, T.M.

    2005-01-01

    The ApparaTus for High precision Experiment on Neutral Antimatter and antihydrogen TRAP collaborations have produced antihydrogen atoms by recombination in a cryogenic antiproton-positron plasma. This paper discusses the motion of the weakly bound atoms in the electric and magnetic field of the plasma and trap. The effective electric field in the moving frame of the atom polarizes the atom, and then gradients in the field exert a force on the atom. An approximate equation of motion for the atom center of mass is obtained by averaging over the rapid internal dynamics of the atom. The only remnant of the atom internal dynamics that enters this equation is the polarizability for the atom. This coefficient is evaluated for the weakly bound and strongly magnetized (guiding center drift) atoms understood to be produced in the antihydrogen experiments. Application of the approximate equation of motion shows that the atoms can be trapped radially in the large space charge field near the edge of the positron column. Also, an example is presented for which there is full three-dimensional trapping, not just radial trapping. Even untrapped atoms follow curved trajectories, and such trajectories are discussed for the important class of atoms that reach a field ionization diagnostic. Finally, the critical field for ionization is determined as an upper bound on the range of applicability of the theory

  16. Pressure Dependence of the Radial Breathing Mode of Carbon Nanotubes: The Effect of Fluid Adsorption

    Science.gov (United States)

    Longhurst, M. J.; Quirke, N.

    2007-04-01

    The pressure dependence of shifts in the vibrational modes of individual carbon nanotubes is strongly affected by the nature of the pressure transmitting medium as a result of adsorption at the nanotube surface. The adsorbate is treated as an elastic shell which couples with the radial breathing mode (RBM) of the nanotube via van der Waal interactions. Using analytical methods as well as molecular simulation, we observe a low frequency breathing mode for the adsorbed fluid at ˜50cm-1, as well as diameter dependent upshifts in the RBM frequency with pressure, suggesting metallic nanotubes may wet more than semiconducting ones.

  17. Use of the upper radial order modes in spherical superconducting cavities

    International Nuclear Information System (INIS)

    Reuss, J.

    1975-04-01

    Spherical cavities resonating on a high g radial order mode are considered. The ratio of the maximum magnetic field inside the cavity to the maximum field on the wall is proportional to g. The proportion coefficient is given for the TEsub(g10); TEsub(g20), TMsub(g10), and TMsub(g20) modes. That corresponds to an energy concentration at the center. Owing to this property the superconducting cavities might be used to produce strong H.F. magnetic fields (larger than 10 Teslas) [fr

  18. Illumination Profile & Dispersion Variation Effects on Radial Velocity Measurements

    Science.gov (United States)

    Grieves, Nolan; Ge, Jian; Thomas, Neil B.; Ma, Bo; Li, Rui; SDSS-III

    2015-01-01

    The Multi-object APO Radial-Velocity Exoplanet Large-Area Survey (MARVELS) measures radial velocities using a fiber-fed dispersed fixed-delay interferometer (DFDI) with a moderate dispersion spectrograph. This setup allows a unique insight into the 2D illumination profile from the fiber on to the dispersion grating. Illumination profile investigations show large changes in the profile over time and fiber location. These profile changes are correlated with dispersion changes and long-term radial velocity offsets, a major problem within the MARVELS radial velocity data. Characterizing illumination profiles creates a method to both detect and correct radial velocity offsets, allowing for better planet detection. Here we report our early results from this study including improvement of radial velocity data points from detected giant planet candidates. We also report an illumination profile experiment conducted at the Kitt Peak National Observatory using the EXPERT instrument, which has a DFDI mode similar to MARVELS. Using profile controlling octagonal-shaped fibers, long term offsets over a 3 month time period were reduced from ~50 m/s to within the photon limit of ~4 m/s.

  19. Instabilities in strongly coupled plasmas

    CERN Document Server

    Kalman, G J

    2003-01-01

    The conventional Vlasov treatment of beam-plasma instabilities is inappropriate when the plasma is strongly coupled. In the strongly coupled liquid state, the strong correlations between the dust grains fundamentally affect the conditions for instability. In the crystalline state, the inherent anisotropy couples the longitudinal and transverse polarizations, and results in unstable excitations in both polarizations. We summarize analyses of resonant and non-resonant, as well as resistive instabilities. We consider both ion-dust streaming and dust beam-plasma instabilities. Strong coupling, in general, leads to an enhancement of the growth rates. In the crystalline phase, a resonant transverse instability can be excited.

  20. Radial cracks and fracture mechanism of radially oriented ring 2:17 type SmCo magnets

    International Nuclear Information System (INIS)

    Tian Jianjun; Pan Dean; Zhou Hao; Yin Fuzheng; Tao Siwu; Zhang Shengen; Qu Xuanhui

    2009-01-01

    Radially oriented ring 2:17 type SmCo magnets have different microstructure in the radial direction (easy magnetization) and axial direction (hard magnetization). The structure of the cross-section in radial direction is close-packed atomic plane, which shows cellular microstructure. The microstructure of the cross-section in axial direction consists of a mixture of rhombic microstructure and parallel lamella phases. So the magnets have obvious anisotropy of thermal expansion in different directions. The difference of the thermal expansion coefficients reaches the maximum value at 830-860 deg. C, which leads to radial cracks during quenching. The magnets have high brittlement because there are fewer slip systems in crystal structure. The fracture is brittle cleavage fracture.