WorldWideScience

Sample records for hybrid em wave

  1. Investigation on High Performance of 10m Semi Anechoic Chamber by using Open-Top Hollow Pyramidal Hybrid EM Wave Absorber

    Science.gov (United States)

    Kurihara, Hiroshi; Saito, Toshifumi; Suzuki, Yoshikazu; Nishikata, Atsuhiro; Hashimoto, Osamu

    The emission radiated from electric and electronic equipments is evaluated through OATS. Recently, it is not fully prepared the environment for OATS because of a variety of communication radiation sources (e.g., digital television broadcast and cellular phone station). Therefore, the EM anechoic chambers are becoming more and more important as EMI test site. On the other hand, the EM anechoic chambers are needed high performance in order to cut down EMI countermeasure cost and calculate the antenna factor. The objective of this paper is mainly to present the EM wave absorber design in order to obtain within ±2dB against the theoretical site attenuation values in the 10m semi anechoic chamber at 30MHz to 300MHz. We get the necessary reflectivity of EM wave absorber by the basic site attenuation equation. We design the open-top hollow pyramidal new hybrid EM wave absorber consisted of 180cm long dielectric loss foam and ferrite tiles. Then, we design the 10m semi anechoic chamber by using the ray-tracing simulation and construct it in the size of L24m×W15.2m×H11.2m. More over, we measure the site attenuation of the constructed 10m semi anechoic chamber by using the broadband calculable dipole antennas. As the result, we confirm the validity of the designed open-top hollow pyramidal new hybrid EM wave absorber.

  2. EMS wave logger data processing

    NARCIS (Netherlands)

    Verhagen, H.J.

    2013-01-01

    Waves can be measured in several ways. One way of measuring waves is by measuring the wave pressure at a certain depth using a pressure sensor and calculate the wave information from the pressure record. The EMS wave logger uses a Honeywell MLH 050 PGP 06A pressure sensor. The information is stored

  3. Travelling waves in hybrid chemotaxis models

    CERN Document Server

    Franz, Benjamin; Painter, Kevin J; Erban, Radek

    2013-01-01

    Hybrid models of chemotaxis combine agent-based models of cells with partial differential equation models of extracellular chemical signals. In this paper, travelling wave properties of hybrid models of bacterial chemotaxis are investigated. Bacteria are modelled using an agent-based (individual-based) approach with internal dynamics describing signal transduction. In addition to the chemotactic behaviour of the bacteria, the individual-based model also includes cell proliferation and death. Cells consume the extracellular nutrient field (chemoattractant) which is modelled using a partial differential equation. Mesoscopic and macroscopic equations representing the behaviour of the hybrid model are derived and the existence of travelling wave solutions for these models is established. It is shown that cell proliferation is necessary for the existence of non-transient (stationary) travelling waves in hybrid models. Additionally, a numerical comparison between the wave speeds of the continuum models and the hybr...

  4. Travelling Waves in Hybrid Chemotaxis Models

    KAUST Repository

    Franz, Benjamin

    2013-12-18

    Hybrid models of chemotaxis combine agent-based models of cells with partial differential equation models of extracellular chemical signals. In this paper, travelling wave properties of hybrid models of bacterial chemotaxis are investigated. Bacteria are modelled using an agent-based (individual-based) approach with internal dynamics describing signal transduction. In addition to the chemotactic behaviour of the bacteria, the individual-based model also includes cell proliferation and death. Cells consume the extracellular nutrient field (chemoattractant), which is modelled using a partial differential equation. Mesoscopic and macroscopic equations representing the behaviour of the hybrid model are derived and the existence of travelling wave solutions for these models is established. It is shown that cell proliferation is necessary for the existence of non-transient (stationary) travelling waves in hybrid models. Additionally, a numerical comparison between the wave speeds of the continuum models and the hybrid models shows good agreement in the case of weak chemotaxis and qualitative agreement for the strong chemotaxis case. In the case of slow cell adaptation, we detect oscillating behaviour of the wave, which cannot be explained by mean-field approximations. © 2013 Society for Mathematical Biology.

  5. Particle acceleration in tangential discontinuities by lower hybrid waves

    Directory of Open Access Journals (Sweden)

    D. Spicer

    2002-01-01

    Full Text Available We consider the role that the lower-hybrid wave turbulence plays in providing the necessary resistivity at collisionless reconnection sights. The mechanism for generating the waves is considered to be the lower-hybrid drift instability. We find that the level of the wave amplitude is sufficient enough to heat and accelerate both electrons and ions.

  6. Hybrid polymer composite membrane for an electromagnetic (EM) valveless micropump

    Science.gov (United States)

    Said, Muzalifah Mohd; Yunas, Jumril; Bais, Badariah; Azlan Hamzah, Azrul; Yeop Majlis, Burhanuddin

    2017-07-01

    In this paper, we report on a hybrid membrane used as an actuator in an electromagnetically driven valveless micropump developed using MEMS processes. The membrane structure consists of the combination of a magnetic polymer composite membrane and an attached bulk permanent magnet which is expected to have a compact structure and a strong magnetic force with maintained membrane flexibility. A soft polymeric material made of polydimethylsiloxane (PDMS) is initially mixed with neodymium magnetic particles (NdFeB) to form a magnetic polymer composite membrane. The membrane is then bonded with the PDMS based microfluidic part, developed using soft lithography process. The developed micropump was tested in terms of the actuator membrane deflection capability and the fluidic flow of the injected fluid sample through the microfluidic channel. The experimental results show that the magnetic composite actuator membrane with an attached bulk permanent magnet is capable of producing a maximum membrane deflection of up to 106 µm. The functionality test of the electromagnetic (EM) actuator for fluid pumping purposes was done by supplying an AC voltage with various amplitudes, signal waves and frequencies. A wide range of sample injection rates from a few µl min-1 to tens of nl min-1 was achieved with a maximum flow rate of 6.6 µl min-1. The injection flow rate of the EM micropump can be controlled by adjusting the voltage amplitude and frequency supplied to the EM coil, to control the membrane deflection in the pump chamber. The designed valveless EM micropump has a very high potential to enhance the drug delivery system capability in biomedical applications.

  7. Full wave simulations of fast wave mode conversion and lower hybrid wave propagation in tokamaks

    DEFF Research Database (Denmark)

    Wright, J.C.; Bonoli, P.T.; Brambilla, M.;

    2004-01-01

    Fast wave (FW) studies of mode conversion (MC) processes at the ion-ion hybrid layer in toroidal plasmas must capture the disparate scales of the FW and mode converted ion Bernstein and ion cyclotron waves. Correct modeling of the MC layer requires resolving wavelengths on the order of k(perpendi......Fast wave (FW) studies of mode conversion (MC) processes at the ion-ion hybrid layer in toroidal plasmas must capture the disparate scales of the FW and mode converted ion Bernstein and ion cyclotron waves. Correct modeling of the MC layer requires resolving wavelengths on the order of k......). Two full wave codes, a massively-parallel-processor (MPP) version of the TORIC-2D finite Larmor radius code [M. Brambilla, Plasma Phys. Controlled Fusion 41, 1 (1999)] and also an all orders spectral code AORSA2D [E. F. Jaeger , Phys. Plasmas 9, 1873 (2002)], have been developed which for the first......)] to gain new understanding into the nature of FWMC in tokamaks. The massively-parallel-processor version of TORIC is also now capable of running with sufficient resolution to model planned lower hybrid range of frequencies experiments in the Alcator C-Mod. (C) 2004 American Institute of Physics....

  8. Stochastic Ion Heating by the Lower-Hybrid Waves

    Science.gov (United States)

    Khazanov, G.; Tel'nikhin, A.; Krotov, A.

    2011-01-01

    The resonance lower-hybrid wave-ion interaction is described by a group (differentiable map) of transformations of phase space of the system. All solutions to the map belong to a strange attractor, and chaotic motion of the attractor manifests itself in a number of macroscopic effects, such as the energy spectrum and particle heating. The applicability of the model to the problem of ion heating by waves at the front of collisionless shock as well as ion acceleration by a spectrum of waves is discussed. Keywords: plasma; ion-cyclotron heating; shocks; beat-wave accelerator.

  9. Gravity Waves from Tachyonic Preheating after Hybrid Inflation

    CERN Document Server

    Dufaux, Jean Francois; Kofman, Lev; Navros, Olga

    2008-01-01

    We study the stochastic background of gravitational waves produced from preheating in hybrid inflation models. We investigate different dynamical regimes of preheating in these models and we compute the resulting gravity wave spectra using analytical estimates and numerical simulations. We discuss the dependence of the gravity wave frequencies and amplitudes on the various potential parameters. We find that large regions of the parameter space leads to gravity waves that may be observable in upcoming interferometric experiments, including Advanced LIGO, but this generally requires very small coupling constants.

  10. DE-1 and COSMOS 1809 observations of lower hybrid waves excited by VLF whistler mode waves

    Science.gov (United States)

    Bell, T. F; Inan, U. S.; Lauben, D.; Sonwalkar, V. S.; Helliwell, R. A.; Sobolev, Ya. P.; Chmyrev, V. M.; Gonzalez, S.

    1994-01-01

    Past work demostrates that strong lower hybrid (LH) waves can be excited by electromagnetic whistler mode waves throughout large regions of the topside ionosphere and magnetosphere. The effects of the excited LH waves upon the suprathermal ion population in the topside ionosphere and magnetosphere depend upon the distribution of LH wave amplitude with wavelength lambda. The present work reports plasma wave data from the DE-1 and COSMOS 1809 spacecraft which suggests that the excited LH wave spectrum has components for which lambda less than or equal to 3.5 m when excitation occurs at a frequency roughly equal to the local lower hybrid resonance frequency. This wavelength limit is a factor of approximately 3 below that reported in past work and suggests that the excited LH waves can interact with suprathermal H(+) ions with energy less than or equal to 6 eV. This finding supports recent work concerning the heating of suprathermal ions above thunderstorm cells.

  11. Lower hybrid waves at the shock front: a reassessment

    Directory of Open Access Journals (Sweden)

    S. N. Walker

    2008-03-01

    Full Text Available The primary process occurring at a collisionless shock is the redistribution of the bulk upstream energy into other degrees of freedom. One part of this process results in the acceleration of electrons at the shock front. Accelerated electrons are observed at the terrestrial and other planetary shocks, comets, and their effects are observed in astrophysical phenomena such as supernova remnants and jets in the form of X-ray bremsstrahlung radiation. One of the physical models for electron acceleration at supercritical shocks is based on low-hybrid turbulence due to the presence of reflected ions in the foot region. Since lower hybrid waves propagate almost perpendicular to the magnetic field they can be simultaneously in resonance with both the unmagnetised ions (ω=Vik and magnetised electrons (ω=Vek||. In this paper, Cluster observations of the electric field are used to study the occurrence of lower hybrid waves in the front of the terrestrial bow shock. It is shown that the lower hybrid waves exist as isolated wave packets. However, the very low level of the observed lower hybrid turbulence is too small to impart significant energisation to the electron population.

  12. Hybridizing matter-wave and classical accelerometers

    Science.gov (United States)

    Lautier, J.; Volodimer, L.; Hardin, T.; Merlet, S.; Lours, M.; Pereira Dos Santos, F.; Landragin, A.

    2014-10-01

    We demonstrate a hybrid accelerometer that benefits from the advantages of both conventional and atomic sensors in terms of bandwidth (DC to 430 Hz) and long term stability. First, the use of a real time correction of the atom interferometer phase by the signal from the classical accelerometer enables to run it at best performance without any isolation platform. Second, a servo-lock of the DC component of the conventional sensor output signal by the atomic one realizes a hybrid sensor. This method paves the way for applications in geophysics and in inertial navigation as it overcomes the main limitation of atomic accelerometers, namely, the dead times between consecutive measurements.

  13. Hybridizing matter-wave and classical accelerometers

    Energy Technology Data Exchange (ETDEWEB)

    Lautier, J.; Volodimer, L.; Hardin, T.; Merlet, S.; Lours, M.; Pereira Dos Santos, F.; Landragin, A., E-mail: arnaud.landragin@obspm.fr [LNE-SYRTE, Observatoire de Paris, CNRS, UPMC, 61 avenue de l' Observatoire, 75014 Paris (France)

    2014-10-06

    We demonstrate a hybrid accelerometer that benefits from the advantages of both conventional and atomic sensors in terms of bandwidth (DC to 430 Hz) and long term stability. First, the use of a real time correction of the atom interferometer phase by the signal from the classical accelerometer enables to run it at best performance without any isolation platform. Second, a servo-lock of the DC component of the conventional sensor output signal by the atomic one realizes a hybrid sensor. This method paves the way for applications in geophysics and in inertial navigation as it overcomes the main limitation of atomic accelerometers, namely, the dead times between consecutive measurements.

  14. Hybridizing matter-wave and classical accelerometers

    CERN Document Server

    Lautier, Jean; Hardin, Thomas; Merlet, Sebastien; Santos, Franck Pereira Dos; Landragin, Arnaud

    2014-01-01

    We demonstrate a hybrid accelerometer that benefits from the advantages of both conventional and atomic sensors in terms of bandwidth (DC to 430 Hz) and long term stability. First, the use of a real time correction of the atom interferometer phase by the signal from the classical accelerometer enables to run it at best performances without any isolation platform. Second, a servo-lock of the DC component of the conventional sensor output signal by the atomic one realizes a hybrid sensor. This method paves the way for applications in geophysics and in inertial navigation as it overcomes the main limitation of atomic accelerometers, namely the dead times between consecutive measurements.

  15. Active graphene-silicon hybrid diode for terahertz waves.

    Science.gov (United States)

    Li, Quan; Tian, Zhen; Zhang, Xueqian; Singh, Ranjan; Du, Liangliang; Gu, Jianqiang; Han, Jiaguang; Zhang, Weili

    2015-05-11

    Controlling the propagation properties of the terahertz waves in graphene holds great promise in enabling novel technologies for the convergence of electronics and photonics. A diode is a fundamental electronic device that allows the passage of current in just one direction based on the polarity of the applied voltage. With simultaneous optical and electrical excitations, we experimentally demonstrate an active diode for the terahertz waves consisting of a graphene-silicon hybrid film. The diode transmits terahertz waves when biased with a positive voltage while attenuates the wave under a low negative voltage, which can be seen as an analogue of an electronic semiconductor diode. Here, we obtain a large transmission modulation of 83% in the graphene-silicon hybrid film, which exhibits tremendous potential for applications in designing broadband terahertz modulators and switchable terahertz plasmonic and metamaterial devices.

  16. Active graphene–silicon hybrid diode for terahertz waves

    Science.gov (United States)

    Li, Quan; Tian, Zhen; Zhang, Xueqian; Singh, Ranjan; Du, Liangliang; Gu, Jianqiang; Han, Jiaguang; Zhang, Weili

    2015-01-01

    Controlling the propagation properties of the terahertz waves in graphene holds great promise in enabling novel technologies for the convergence of electronics and photonics. A diode is a fundamental electronic device that allows the passage of current in just one direction based on the polarity of the applied voltage. With simultaneous optical and electrical excitations, we experimentally demonstrate an active diode for the terahertz waves consisting of a graphene–silicon hybrid film. The diode transmits terahertz waves when biased with a positive voltage while attenuates the wave under a low negative voltage, which can be seen as an analogue of an electronic semiconductor diode. Here, we obtain a large transmission modulation of 83% in the graphene–silicon hybrid film, which exhibits tremendous potential for applications in designing broadband terahertz modulators and switchable terahertz plasmonic and metamaterial devices. PMID:25959596

  17. Active graphene-silicon hybrid diode for terahertz waves

    Science.gov (United States)

    Li, Quan; Tian, Zhen; Zhang, Xueqian; Singh, Ranjan; Du, Liangliang; Gu, Jianqiang; Han, Jiaguang; Zhang, Weili

    2015-05-01

    Controlling the propagation properties of the terahertz waves in graphene holds great promise in enabling novel technologies for the convergence of electronics and photonics. A diode is a fundamental electronic device that allows the passage of current in just one direction based on the polarity of the applied voltage. With simultaneous optical and electrical excitations, we experimentally demonstrate an active diode for the terahertz waves consisting of a graphene-silicon hybrid film. The diode transmits terahertz waves when biased with a positive voltage while attenuates the wave under a low negative voltage, which can be seen as an analogue of an electronic semiconductor diode. Here, we obtain a large transmission modulation of 83% in the graphene-silicon hybrid film, which exhibits tremendous potential for applications in designing broadband terahertz modulators and switchable terahertz plasmonic and metamaterial devices.

  18. Active graphene–silicon hybrid diode for terahertz waves

    OpenAIRE

    Li, Quan; Tian, Zhen; Zhang, Xueqian; Singh, Ranjan; Du, Liangliang; Gu, Jianqiang; Han, Jiaguang; Zhang, Weili

    2015-01-01

    Controlling the propagation properties of the terahertz waves in graphene holds great promise in enabling novel technologies for the convergence of electronics and photonics. A diode is a fundamental electronic device that allows the passage of current in just one direction based on the polarity of the applied voltage. With simultaneous optical and electrical excitations, we experimentally demonstrate an active diode for the terahertz waves consisting of a graphene–silicon hybrid film. The di...

  19. A stochastic background of gravitational waves from hybrid preheating

    CERN Document Server

    García-Bellido, J; Garcia-Bellido, Juan; Figueroa, Daniel G.

    2006-01-01

    The process of reheating the universe after hybrid inflation is extremely violent. It proceeds through the nucleation and subsequent collision of large concentrations of energy density in bubble-like structures, which generate a significant fraction of energy in the form of gravitational waves. We study the power spectrum of the stochastic background of gravitational waves produced at reheating after hybrid inflation. We find that the amplitude could be significant for high-scale models, although the typical frequencies are well beyond what could be reached by planned gravitational wave observatories like LIGO, LISA or BBO. On the other hand, low-scale models could still produce a detectable stochastic background at frequencies accesible to those detectors. The discovery of such a background would open a new window into the very early universe.

  20. A Gravitational Wave Background from Reheating after Hybrid Inflation

    CERN Document Server

    Garcia-Bellido, Juan; Sastre, Alfonso

    2007-01-01

    The reheating of the universe after hybrid inflation proceeds through the nucleation and subsequent collision of large concentrations of energy density in the form of bubble-like structures moving at relativistic speeds. This generates a significant fraction of energy in the form of a stochastic background of gravitational waves, whose time evolution is determined by the successive stages of reheating. First, tachyonic preheating makes the amplitude of gravity waves grow exponentially fast. Second, bubble collisions add a new burst of gravitational radiation. Third, turbulent motions finally produce a self-similar time evolution, which allows us to extrapolate the amplitude and shape of this background till the end of reheating. We find that the fraction of energy density today in these primordial gravitational waves could be significant for GUT-scale models of inflation, although well beyond the frequency range sensitivity of gravitational wave observatories like LIGO, LISA or BBO. However, low-scale models ...

  1. Double hybrid inflation and gravitational waves

    CERN Document Server

    Lazarides, G

    2015-01-01

    A double hybrid inflationary scenario in non-minimal supergravity which can predict values of the tensor-to-scalar ratio up to about 0.05 is presented. Larger values of this ratio would require unacceptably large running of the scalar spectral index. The underlying supersymmetric particle physics model possesses, for the chosen values of the parameters, practically two inflationary paths, the trivial and the semi-shifted one. The trivial path is stabilized by supergravity and supports a first stage of inflation with a limited number of e-foldings. The tensor-to-scalar ratio can become appreciable with the scalar spectral index remaining acceptable, as a result of the competition between the relatively mild supergravity and the strong radiative corrections to the inflationary potential. The additional number of e-foldings required for solving the puzzles of hot big bang cosmology are generated by a second stage of inflation along the semi-shifted path. This is possible only because the semi-shifted path is alm...

  2. EM-wave absorption properties of hollow spiral iron particles

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Wenqiang, E-mail: zwqcau@gmail.com [College of Engineering, China Agricultural University, Beijing 100083 (China); Bionic and Micro/Nano/Bio Manufacturing Technology Research Center, Beihang University, Beijing 100191 (China); Zhang, Deyuan [Bionic and Micro/Nano/Bio Manufacturing Technology Research Center, Beihang University, Beijing 100191 (China)

    2015-12-15

    Hollow iron spiral particles were fabricated successfully by thermal decomposition method, and they were heat-treated at different temperatures in N{sub 2} atmosphere. The electromagnetic wave absorption properties of hollow iron spiral particles were investigated ranging between 1 GHz and 18 GHz. The results indicated that the phase structures of the particles changed from amorphous to nanocrystal with the treating temperature rising, also causing the significant change in electromagnetic parameters and the reflection loss. The reflection loss could reach −33 dB at 16.2 GHz, indicating that the hollow iron spiral particles had the potential to be used in prepare the a high property EM-wave absorber. - Highlights: • Hollow iron spiral particles were fabricated by thermal decomposition method. • The particles changed from amorphous to nanocrystals with heat-treatment. • Particles’ EM-parameters have a great change after high temperature heat-treatment. • RL results show the particles have potential to be high property EM-wave absorber.

  3. Plasma-maser instability of the ion acoustics wave in the presence of lower hybrid wave turbulence in inhomogeneous plasma

    Indian Academy of Sciences (India)

    M Singh; P N Deka

    2006-03-01

    A theoretical study is made on the generation mechanism of ion acoustics wave in the presence of lower hybrid wave turbulence field in inhomogeneous plasma on the basis of plasma-maser interaction. The lower hybrid wave turbulence field is taken as the low-frequency turbulence field. The growth rate of test high frequency ion acoustics wave is obtained with the involvement of spatial density gradient parameter. A comparative study of the role of density gradient for the generation of ion acoustics wave on the basis of plasma-maser effect is presented. It is found that the density gradient influences the growth rate of ion acoustics wave.

  4. Hybrid Modeling of Elastic Wave Scattering in a Welded Cylinder

    Science.gov (United States)

    Mahmoud, A.; Shah, A. H.; Popplewell, N.

    2003-03-01

    In the present study, a 3D hybrid method, which couples the finite element region with guided elastic wave modes, is formulated to investigate the scattering by a non-axisymmetric crack in a welded steel pipe. The algorithm is implemented on a parallel computing platform. Implementation is facilitated by the dynamic memory allocation capabilities of Fortran 90™ and the parallel processing directives of OpenMp™. The algorithm is validated against available numerical results. The agreement with a previous 2D hybrid model is excellent. Novel results are presented for the scattering of the first longitudinal mode from different non-axisymmetric cracks. The trend of the new results is consistent with the previous findings for the axisymmetric case. The developed model has potential application in ultrasonic nondestructive evaluation of welded steel pipes.

  5. Stochastic generation of currents by lower-hybrid waves

    Energy Technology Data Exchange (ETDEWEB)

    Gell, Y.; Nakach, R.

    1984-03-01

    A scheme for current generation based on a stochastic driving mechanism is proposed. The current in this approach is generated by launching into the plasma two lower-hybrid waves having appropriate different frequencies, wave numbers, and amplitudes. The phase-space analysis of the electron motion in such a configuration reveals the existence of a relatively broad stochastic layer far away from the separatrix, allowing for diffusion in velocity space of high-velocity electrons. The diffusion coefficient of this process is evaluated and the solution of the Fokker-Planck equation for the electron velocity distribution function is used to calculate the current J and the power dissipated P/sub d/ in generating it. A favorable J-to-P/sub d/ ratio for steady-current drive is found.

  6. Full Wave Simulation of Integrated Circuits Using Hybrid Numerical Methods

    Science.gov (United States)

    Tan, Jilin

    Transmission lines play an important role in digital electronics, and in microwave and millimeter-wave circuits. Analysis, modeling, and design of transmission lines are critical to the development of the circuitry in the chip, subsystem, and system levels. In the past several decays, at the EM modeling level, the quasi-static approximation has been widely used due to its great simplicity. As the clock rates increase, the inter-connect effects such as signal delay, distortion, dispersion, reflection, and crosstalk, limit the performance of microwave systems. Meanwhile, the quasi-static approach loses its validity for some complex system structures. Since the successful system design of the PCB, MCM, and the chip packaging, rely very much on the computer aided EM level modeling and simulation, many new methods have been developed, such as the full wave approach, to guarantee the successful design. Many difficulties exist in the rigorous EM level analysis. Some of these include the difficulties in describing the behavior of the conductors with finite thickness and finite conductivity, the field singularity, and the arbitrary multilayered multi-transmission lines structures. This dissertation concentrates on the full wave study of the multi-conductor transmission lines with finite conductivity and finite thickness buried in an arbitrary lossy multilayered environment. Two general approaches have been developed. The first one is the integral equation method in which the dyadic Green's function for arbitrary layered media has been correctly formulated and has been tested both analytically and numerically. By applying this method, the double layered high dielectric permitivitty problem and the heavy dielectrical lossy problem in multilayered media in the CMOS circuit design have been solved. The second approach is the edge element method. In this study, the correct functional for the two dimensional propagation problem has been successfully constructed in a rigorous way

  7. The effect of lower hybrid waves on JET plasma rotation

    Science.gov (United States)

    Nave, M. F. F.; Kirov, K.; Bernardo, J.; Brix, M.; Ferreira, J.; Giroud, C.; Hawkes, N.; Hellsten, T.; Jonsson, T.; Mailloux, J.; Ongena, J.; Parra, F.; Contributors, JET

    2017-03-01

    This paper reports on observations of rotation in JET plasmas with lower hybrid current drive. Lower hybrid (LH) has a clear impact on rotation. The changes in core rotation can be either in the co- or counter-current directions. Experimental features that could determine the direction of rotation were investigated. Changes from co- to counter-rotation as the q-profile evolves from above unity to below unity suggests that magnetic shear could be important. However, LH can drive either co- or counter-rotation in discharges with similar magnetic shear and at the same plasma current. It is not clear if a slightly lower density is significant. A power scan at fixed density, shows a lower hybrid power threshold around 3 MW. For smaller LH powers, counter rotation increases with power, while for larger powers a trend towards co-rotation is found. The estimated counter-torque from the LH waves, would not explain the observed angular frequencies, neither would it explain the observation of co-rotation.

  8. Incommensurate Chirality Density Wave Transition in a Hybrid Molecular Framework

    Science.gov (United States)

    Hill, Joshua A.; Christensen, Kirsten E.; Goodwin, Andrew L.

    2017-09-01

    Using single-crystal x-ray diffraction we characterize the 235 K incommensurate phase transition in the hybrid molecular framework tetraethylammonium silver(I) dicyanoargentate, [NEt4]Ag3(CN )4 . We demonstrate the transition to involve spontaneous resolution of chiral [NEt4]+ conformations, giving rise to a state in which molecular chirality is incommensurately modulated throughout the crystal lattice. We refer to this state as an incommensurate chirality density wave (XDW) phase, which represents a fundamentally new type of chiral symmetry breaking in the solid state. Drawing on parallels to the incommensurate ferroelectric transition of NaNO2 , we suggest the XDW state arises through coupling between acoustic (shear) and molecular rotoinversion modes. Such coupling is symmetry forbidden at the Brillouin zone center but symmetry allowed for small but finite modulation vectors q =[0 ,0 ,qz]* . The importance of long-wavelength chirality modulations in the physics of this hybrid framework may have implications for the generation of mesoscale chiral textures, as required for advanced photonic materials.

  9. Speech articulator measurements using low power EM-wave sensors

    Energy Technology Data Exchange (ETDEWEB)

    Holzrichter, J.F.; Burnett, G.C.; Ng, L.C. [Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94551 (United States); Lea, W.A. [Speech Science Institute, P.O. Box 240428, Apple Valley, Minnesota 55124 (United States)

    1998-01-01

    Very low power electromagnetic (EM) wave sensors are being used to measure speech articulator motions as speech is produced. Glottal tissue oscillations, jaw, tongue, soft palate, and other organs have been measured. Previously, microwave imaging (e.g., using radar sensors) appears not to have been considered for such monitoring. Glottal tissue movements detected by radar sensors correlate well with those obtained by established laboratory techniques, and have been used to estimate a voiced excitation function for speech processing applications. The noninvasive access, coupled with the small size, low power, and high resolution of these new sensors, permit promising research and development applications in speech production, communication disorders, speech recognition and related topics. {copyright} {ital 1998 Acoustical Society of America.}

  10. Long-wave approximation for hybridization modeling of local surface plasmonic resonance in nanoshells.

    Science.gov (United States)

    Li, Ben Q; Liu, Changhong

    2011-01-15

    A hybridization model for the localized surface plasmon resonance of a nanoshell is developed within the framework of long-wave approximation. Compared with the existing hybridization model derived from the hydrodynamic simulation of free electron gas, this approach is much simpler and gives identical results for a concentric nanoshell. Also, with this approach, the limitations associated with the original hybridization model are succinctly stated. Extension of this approach to hybridization modeling of more complicated structures such as multiplayered nanoshells is straightforward.

  11. Electromagnetic Components of Auroral Hiss and Lower Hybrid Waves in the Polar Magnetosphere

    Science.gov (United States)

    Wong, H. K.

    1995-01-01

    DE-1 has frequently observed waves in the whistler and lower hybrid frequencies range. Besides the electrostatic components, these waves also exhibit electromagnetic components. It is generally believed that these waves are excited by the electron acoustic instability and the electron-beam-driven lower hybrid instability. Because the electron acoustic and the lower hybrid waves are predominately electrostatic waves, they cannot account for the observed electromagnetic components. In this work, it is suggested that these electromagnetic components can be explained by waves that are generated near the resonance cone and that propagate away from the source. The role that these electromagnetic waves can play in particle acceleration processes at low altitude is discussed.

  12. A Hybrid Aggressive Space Mapping Algorithm for EM Optimization

    DEFF Research Database (Denmark)

    Bakr, M.; Bandler, J. W.; Georgieva, N.;

    1999-01-01

    We present a novel, Hybrid Aggressive Space Mapping (HASM) optimization algorithm. HASM is a hybrid approach exploiting both the Trust Region Aggressive Space Mapping (TRASM) algorithm and direct optimization. It does not assume that the final space-mapped design is the true optimal design and is...

  13. Multiscale modeling for classification of SAR imagery using hybrid EM algorithm and genetic algorithm

    Institute of Scientific and Technical Information of China (English)

    Xianbin Wen; Hua Zhang; Jianguang Zhang; Xu Jiao; Lei Wang

    2009-01-01

    A novel method that hybridizes genetic algorithm (GA) and expectation maximization (EM) algorithm for the classification of syn-thetic aperture radar (SAR) imagery is proposed by the finite Gaussian mixtures model (GMM) and multiscale autoregressive (MAR)model. This algorithm is capable of improving the global optimality and consistency of the classification performance. The experiments on the SAR images show that the proposed algorithm outperforms the standard EM method significantly in classification accuracy.

  14. Special purpose hybrid transfinite elements and unified computational methodology for accurately predicting thermoelastic stress waves

    Science.gov (United States)

    Tamma, Kumar K.; Railkar, Sudhir B.

    1988-01-01

    This paper represents an attempt to apply extensions of a hybrid transfinite element computational approach for accurately predicting thermoelastic stress waves. The applicability of the present formulations for capturing the thermal stress waves induced by boundary heating for the well known Danilovskaya problems is demonstrated. A unique feature of the proposed formulations for applicability to the Danilovskaya problem of thermal stress waves in elastic solids lies in the hybrid nature of the unified formulations and the development of special purpose transfinite elements in conjunction with the classical Galerkin techniques and transformation concepts. Numerical test cases validate the applicability and superior capability to capture the thermal stress waves induced due to boundary heating.

  15. Intermodal parametric gain of degenerate four wave mixing in large mode area hybrid photonic crystal fibers

    OpenAIRE

    Petersen, Sidsel Rübner; Lægsgaard, Jesper; Alkeskjold, Thomas Tanggaard

    2013-01-01

    Intermodal degenerate four wave mixing (FWM) is investigated numerically in large mode area hybrid photonic crystal fibers. The dispersion is controlled independently of core size, and thus allows for power scaling of the FWM process.

  16. Frequency conversion through spontaneous degenerate four wave mixing in large mode area hybrid photonic crystal fibers

    DEFF Research Database (Denmark)

    Petersen, Sidsel Rübner; Alkeskjold, Thomas Tanggaard; Olausson, Christina Bjarnal Thulin;

    2014-01-01

    Frequency conversion through spontaneous degenerate four wave mixing (FWM) is investigated in large mode area hybrid photonic crystal fibers. Different FWM processes are observed, phasematching between fiber modes of orthogonal polarization, intermodal phasematching across bandgaps, and intramodal...

  17. Intermodal parametric gain of degenerate four wave mixing in large mode area hybrid photonic crystal fibers

    DEFF Research Database (Denmark)

    Petersen, Sidsel Rübner; Lægsgaard, Jesper; Alkeskjold, Thomas Tanggaard

    2013-01-01

    Intermodal degenerate four wave mixing (FWM) is investigated numerically in large mode area hybrid photonic crystal fibers. The dispersion is controlled independently of core size, and thus allows for power scaling of the FWM process.......Intermodal degenerate four wave mixing (FWM) is investigated numerically in large mode area hybrid photonic crystal fibers. The dispersion is controlled independently of core size, and thus allows for power scaling of the FWM process....

  18. Polarization switch of four-wave mixing in large mode area hybrid photonic crystal fibers

    DEFF Research Database (Denmark)

    Petersen, Sidsel Rübner; Alkeskjold, Thomas Tanggaard; Olausson, Christina Bjarnal Thulin;

    2015-01-01

    Degenerate spontaneous four-wave mixing is considered in a large mode area hybrid photonic crystal fiber. Numerical and experimental results show birefringence assisted four-wave mixing for a certain polarization state of the pump field. The parametric gain can be turned on and off by switching...... the polarization state of the pump field between the two principal axis of the hybrid photonic crystal fiber. (C) 2015 Optical Society of America...

  19. Polarization switch of four-wave mixing in large mode area hybrid photonic crystal fibers.

    Science.gov (United States)

    Petersen, Sidsel R; Alkeskjold, Thomas T; Olausson, Christina B; Lægsgaard, Jesper

    2015-02-15

    Degenerate spontaneous four-wave mixing is considered in a large mode area hybrid photonic crystal fiber. Numerical and experimental results show birefringence assisted four-wave mixing for a certain polarization state of the pump field. The parametric gain can be turned on and off by switching the polarization state of the pump field between the two principal axis of the hybrid photonic crystal fiber.

  20. Biometric analysis of interspecific hybrids between Rosa canina L. and Rosa rubiginosa L. (section Caninae DC. em. Christ.

    Directory of Open Access Journals (Sweden)

    Anna Sołtys-Lelek

    2016-06-01

    Full Text Available The article presents the biometric analysis of selected morphological features of interspecies hybrid Rosa canina L. × R. rubiginosa L. This hybrid was the result of spontaneous hybridization between the two species falling into section Caninae DC. em. Christ. So far, it has not been studied in terms of morphological characteristics, in particular with respect to the parental forms.

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

    Institute of Scientific and Technical Information of China (English)

    方瑜德; 石跃江; 匡光力; 刘岳修; 沈慰慈; 丁伯江

    2001-01-01

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

  2. Design of a plasmonic-organic hybrid slot waveguide integrated with a bowtie-antenna for terahertz wave detection

    CERN Document Server

    Zhang, Xingyu; Subbaraman, Harish; Pan, Zeyu; Chen, Chin-Ta; Chen, Ray T

    2016-01-01

    Electromagnetic (EM) wave detection over a large spectrum has recently attracted significant amount of attention. Traditional electronic EM wave sensors use large metallic probes which distort the field to be measured and also have strict limitations on the detectable RF bandwidth. To address these problems, integrated photonic EM wave sensors have been developed to provide high sensitivity and broad bandwidth. Previously we demonstrated a compact, broadband, and sensitive integrated photonic EM wave sensor, consisting of an organic electro-optic (EO) polymer refilled silicon slot photonic crystal waveguide (PCW) modulator integrated with a gold bowtie antenna, to detect the X band of the electromagnetic spectrum. However, due to the relative large RC constant of the silicon PCW, such EM wave sensors can only work up to tens of GHz. In this work, we present a detailed design and discussion of a new generation of EM wave sensors based on EO polymer refilled plasmonic slot waveguides in conjunction with bowtie ...

  3. A Laboratory Experiment on EM Backscatter from Farley-Buneman and Gradient Drift Waves

    DEFF Research Database (Denmark)

    Alport, M. J.; D'Angelo, N.; Pécseli, Hans

    1981-01-01

    Results are reported of a laboratory experiment on Bragg backscatter of 3-cm microwaves by turbulent waves driven by the Farley-Buneman and gradient drift instabilities. The present work is the third in a series of laboratory experiments performed to test, under controlled conditions, prevalent...... ideas on EM scattering by equatorial and high-latitude ionospheric waves and irregularities....

  4. A Hybrid Aggressive Space Mapping Algorithm for EM Optimization

    DEFF Research Database (Denmark)

    Bakr, Mohamed H.; Bandler, John W.; Georgieva, N.;

    1999-01-01

    We propose a novel hybrid aggressive space-mapping (HASM) optimization algorithm. HASM exploits both the trust-region aggressive space-mapping (TRASM) strategy and direct optimization. Severe differences between the coarse and fine models and nonuniqueness of the parameter extraction procedure ma...

  5. Alpha Channeling with High-field Launch of Lower Hybrid Waves

    CERN Document Server

    Ochs, Ian E; Fisch, Nathaniel J

    2015-01-01

    Although lower hybrid waves are effective at driving currents in present-day tokamaks, they are expected to interact strongly with high-energy particles in extrapolating to reactors. In the presence of a radial alpha particle birth gradient, this interaction can take the form of wave amplification rather than damping. While it is known that this amplification more easily occurs when launching from the tokamak high-field side, the extent of this amplification has not been made quantitative. Here, by tracing rays launched from the high- field-side of a tokamak, the required radial gradients to achieve amplification are calculated for a temperature and density regime consistent with a hot-ion-mode fusion reactor. These simulations, while valid only in the linear regime of wave amplification, nonetheless illustrate the possibilities for wave amplification using high-field launch of the lower hybrid wave.

  6. SDN Controlled mmWave Massive MIMO Hybrid Precoding for 5G Heterogeneous Mobile Systems

    Directory of Open Access Journals (Sweden)

    Na Chen

    2016-01-01

    Full Text Available In 5G mobile network, millimeter wave (mmWave and heterogeneous networks (Hetnets are significant techniques to sustain coverage and spectral efficiency. In this paper, we utilize the hybrid precoding to overcome hardware constraints on the analog-only beamforming in mmWave systems. Particularly, we identify the complicated antenna coordination and vast spatial domain information as the outstanding challenges in mmWave Hetnets. In our work, we employ software defined network (SDN to accomplish radio resource management (RRM and achieve flexible spacial coordination in mmWave Hetnets. In our proposed scheme, SDN controller is responsible for collecting the user channel state information (CSI and applying hybrid precoding based on the calculated null-space of victim users. Simulation results show that our design can effectively reduce the interference to victim users and support high quality of service.

  7. Parametric decay of plasma waves near the upper-hybrid resonance

    Science.gov (United States)

    Dodin, I. Y.; Arefiev, A. V.

    2017-03-01

    An intense X wave propagating perpendicularly to dc magnetic field is unstable with respect to a parametric decay into an electron Bernstein wave and a lower-hybrid wave. A modified theory of this effect is proposed that extends to the high-intensity regime, where the instability rate γ ceases to be a linear function of the incident-wave amplitude. An explicit formula for γ is derived and expressed in terms of cold-plasma parameters. Theory predictions are in reasonable agreement with the results of the particle-in-cell simulations presented in a separate publication.

  8. Four-wave parametric amplification in semiconductor quantum dot-metallic nanoparticle hybrid molecules.

    Science.gov (United States)

    Li, Jian-Bo; He, Meng-Dong; Chen, Li-Qun

    2014-10-06

    We study theoretically four-wave parametric amplification arising from the nonlinear optical response of hybrid molecules composed of semiconductor quantum dots and metallic nanoparticles. It is shown that highly efficient four-wave parametric amplification can be achieved by adjusting the frequency and intensity of the pump field and the distance between the quantum dot and the metallic nanoparticle. Specifically, the induced probe-wave gain is tunable in a large range from 1 to 1.43 × 10⁵. This gain reaches its maximum at the position of three-photon resonance. Our findings hold great promise for developing four-wave parametric oscillators.

  9. Poloidal rotation induced by injecting lower hybrid waves in tokamak plasma edge

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The poloidal rotation of the magnetized edge plasma in tokamak driven by theponderomotive force which is generated by injecting lower hybrid wave(LHW) electric field hasbeen studied. The LHW is launched from a waveguide in the plasma edge, and by Brambilla’sgrill theory, analytic expressions for the wave electric field in the slab model of an inhomogeneouscold plasma have been derived. It is shown that a strong wave electric field will be generated inthe plasma edge by injecting LH wave of the power in MW magnitude, and this electric field willinduce a poloidal rotation with a sheared poloidal velocity.PACS: 52.55.Fa

  10. Interaction of runaway electrons with lower hybrid waves via anomalous Doppler broadening

    Science.gov (United States)

    Martín-Solís, J. R.; Sánchez, R.; Esposito, B.

    2002-05-01

    Due to the relativistic decrease of the electron cyclotron frequency, a cyclotron resonance may appear between runaway electrons and lower hybrid waves. A single particle description of the runaway dynamics [J. R. Martín-Solís et al., Phys. Plasmas 5, 2370 (1998)] is extended to analyze the effect of the interaction of runaway electrons with lower hybrid waves via anomalous Doppler broadening. The conditions under which the resonant interaction can play a role in limiting the runaway energy are established and it is shown that, under typical lower hybrid current drive operation parameters, an efficient wave-particle coupling may occur. Observations of a fast pitch angle scattering event during the current decay phase of Ohmic discharges in the Toroidal Experiment for Technically Oriented Research (TEXTOR) [R. J. E. Jaspers, Ph.D. thesis, Technical University Eindhoven (1995)] are interpreted in terms of such interaction.

  11. A hybrid continuous-wave terahertz imaging system

    Energy Technology Data Exchange (ETDEWEB)

    Dolganova, Irina N., E-mail: in.dolganova@gmail.com; Zaytsev, Kirill I., E-mail: kirzay@gmail.ru; Metelkina, Anna A.; Karasik, Valeriy E.; Yurchenko, Stanislav O., E-mail: st.yurchenko@mail.ru [Bauman Moscow State Technical University, 2nd Baumanskaya str. 5, Moscow 105005 (Russian Federation)

    2015-11-15

    A hybrid (active-passive mode) terahertz (THz) imaging system and an algorithm for imaging synthesis are proposed to enhance the THz image quality. The concept of image contrast is used to compare active and passive THz imaging. Combining the measurement of the self-emitted radiation of the object with the back-scattered source radiation measurement, it becomes possible to use the THz image to retrieve maximum information about the object. The experimental results confirm the advantages of hybrid THz imaging systems, which can be generalized for a wide range of applications in the material sciences, chemical physics, bio-systems, etc.

  12. Transverse ion acceleration by localized lower hybrid waves in the topside auroral ionosphere

    Energy Technology Data Exchange (ETDEWEB)

    Vago, J.L.

    1992-01-01

    Up to now, observations had been unable to show conclusively a one-to-one correspondence between perpendicular ion acceleration and a particular type of plasma wave within the O(+) source region below 2000 km. In this thesis, the author demonstrates that intense (100-300 mV/m) lower hybrid waves are responsible for transversely accelerating H(+) and O(+) ions to characteristic energies of up to 6 eV. This wave-particle interaction takes place in thin filamentary density cavities oriented along geomagnetic field lines. The measurements discussed were conducted in the nightside auroral zone at altitudes between 500 km and 1100 km. The results are consistent with theories of lower hybrid wave condensation and collapse.

  13. Transverse ion acceleration by localized lower hybrid waves in the topside auroral ionosphere

    Energy Technology Data Exchange (ETDEWEB)

    Vago, J.L.; Kintner, P.M.; Chesney, S.W.; Arnoldy, R.L.; Lynch, K.A.; Moore, T.E.; Pollock, C.J. (Cornell Univ., Ithaca, NY (United States) New Hampshire Univ., Durham (United States) NASA, Marshall Space Flight Center, Huntsville, AL (United States))

    1992-11-01

    Up to now, observations had been unable to show conclusively a one-to-one correspondence between perpendicular ion acceleration and a particular type of plasma wave within the O(+) source region below 2000 km. In this paper we demonstrate that intense (100-300 mV/m) lower hybrid waves are responsible for transversely accelerating H(+) and O(+) ions to characteristic energies of up to 6 eV. This wave-particle interaction takes place in thin filamentary density cavities oriented along geomagnetic field lines. The measurements we discuss were conducted in the nightside auroral zone at latitudes between 500 km and 1100 km. Our results are consistent with theories of lower hybrid wave condensation and collapse. 50 refs.

  14. Transverse ion acceleration by localized lower hybrid waves in the topside auroral ionosphere

    Science.gov (United States)

    Vago, J. L.; Kintner, P. M.; Chesney, S. W.; Arnoldy, R. L.; Lynch, K. A.; Moore, T. E.; Pollock, C. J.

    1992-01-01

    Up to now, observations had been unable to show conclusively a one-to-one correspondence between perpendicular ion acceleration and a particular type of plasma wave within the O(+) source region below 2000 km. In this paper we demonstrate that intense (100-300 mV/m) lower hybrid waves are responsible for transversely accelerating H(+) and O(+) ions to characteristic energies of up to 6 eV. This wave-particle interaction takes place in thin filamentary density cavities oriented along geomagnetic field lines. The measurements we discuss were conducted in the nightside auroral zone at latitudes between 500 km and 1100 km. Our results are consistent with theories of lower hybrid wave condensation and collapse.

  15. Hybrid localized waves supported by resonant anisotropic metasurfaces

    DEFF Research Database (Denmark)

    Bogdanov, A. A.; Yermakov, O. Y.; Ovcharenko, A. I.

    2016-01-01

    We study both theoretically and experimentally a new class of surface electromagnetic waves supported by resonant anisotropic metasurface. At certain frequency this type of metasurface demonstrates the topological transition from elliptical to hyperbolic regime.......We study both theoretically and experimentally a new class of surface electromagnetic waves supported by resonant anisotropic metasurface. At certain frequency this type of metasurface demonstrates the topological transition from elliptical to hyperbolic regime....

  16. Evaluation of thermally induced non-Fourier stress wave disturbances via tailored hybrid transfinite element formulations

    Science.gov (United States)

    Tamma, Kumar K.; Railkar, Sudhir B.

    1989-01-01

    Accurate solutions have been obtained for a class of non-Fourier models in dynamic thermoelasticity which are relevant to the understanding of thermally-induced stress wave disturbances. The method employs tailored hybrid formulations based on the transfinite element approach. The results show that significant thermal stresses may arise due to non-Fourier effects, especially when the speeds of propagation of the thermal and stress waves are equal.

  17. A rapid, fully non-contact, hybrid system for generating Lamb wave dispersion curves.

    Science.gov (United States)

    Harb, M S; Yuan, F G

    2015-08-01

    A rapid, fully non-contact, hybrid system which encompasses an air-coupled transducer (ACT) and a laser Doppler vibrometer (LDV) is presented for profiling A0 Lamb wave dispersion of an isotropic aluminum plate. The ACT generates ultrasonic pressure incident upon the surface of the plate. The pressure waves are partially refracted into the plate. The LDV is employed to measure the out-of-plane velocity of the excited Lamb wave mode at some distances where the Lamb waves are formed in the plate. The influence of the ACT angle of incidence on Lamb wave excitation is investigated and Snell's law is used to directly compute Lamb wave dispersion curves including phase and group velocity dispersion curves in aluminum plates from incident angles found to generate optimal A0 Lamb wave mode. The measured curves are compared to results obtained from a two-dimensional (2-D) Fast Fourier transform (FFT), Morlet wavelet transform (MWT) and theoretical predictions. It was concluded that the experimental results obtained using Snell's law concept are well in accordance with the theoretical solutions. The high degree of accuracy in the measured data with the theoretical results proved a high sensitivity of the air-coupled and laser ultrasound in characterizing Lamb wave dispersion in plate-like structures. The proposed non-contact hybrid system can effectively characterize the dispersive relation without knowledge of neither the materials characteristics nor the mathematical model.

  18. Hybrid dispersive media with controllable wave propagation: A new take on smart materials

    Energy Technology Data Exchange (ETDEWEB)

    Bergamini, Andrea E., E-mail: andrea.bergamini@empa.ch [Empa, Materials Science and Technology, Laboratory for Mechanical Integrity of Energy Systems, Überlandstrasse 129, CH-8600, Dübendorf (Switzerland); Zündel, Manuel [ETH Zürich, Institute of Mechanical Systems, Leonhardstrasse 21, CH-8092 Zürich (Switzerland); Flores Parra, Edgar A.; Ermanni, Paolo [ETH Zürich, Composite Materials and Adaptive Structures Laboratory, Leonhardstrasse 21, CH-8092 Zürich (Switzerland); Delpero, Tommaso [Empa, Materials Science and Technology, Laboratory for Mechanical Integrity of Energy Systems, Überlandstrasse 129, CH-8600 Dübendorf (Switzerland); Ruzzene, Massimo [Georgia Institute of Technology, G.W. Woodruff School of Mechanical Engineering, 801 Ferst Drive, Atlanta, Georgia 30332-0405 (United States)

    2015-10-21

    In this paper, we report on the wave transmission characteristics of a hybrid one dimensional (1D) medium. The hybrid characteristic is the result of the coupling between a 1D mechanical waveguide in the form of an elastic beam, supporting the propagation of transverse waves and a discrete electrical transmission line, consisting of a series of inductors connected to ground through capacitors. The capacitors correspond to a periodic array of piezoelectric patches that are bonded to the beam and that couple the two waveguides. The coupling leads to a hybrid medium that is characterized by a coincidence condition for the frequency/wavenumber value corresponding to the intersection of the branches of the two waveguides. In the frequency range centered at coincidence, the hybrid medium features strong attenuation of wave motion as a result of the energy transfer towards the electrical transmission line. This energy transfer, and the ensuing attenuation of wave motion, is alike the one obtained through internal resonating units of the kind commonly used in metamaterials. However, the distinct shape of the dispersion curves suggests how this energy transfer is not the result of a resonance and is therefore fundamentally different. This paper presents the numerical investigation of the wave propagation in the considered media, it illustrates experimental evidence of wave transmission characteristics and compares the performance of the considered configuration with that of internal resonating metamaterials. In addition, the ability to conveniently tune the dispersion properties of the electrical transmission line is exploited to adapt the periodicity of the domain and to investigate diatomic periodic configurations that are characterized by a richer dispersion spectrum and broader bandwidth of wave attenuation at coincidence. The medium consisting of mechanical, piezoelectric, and analog electronic elements can be easily interfaced to digital devices to offer a novel

  19. Hybrid dispersive media with controllable wave propagation: A new take on smart materials

    Science.gov (United States)

    Bergamini, Andrea E.; Zündel, Manuel; Flores Parra, Edgar A.; Delpero, Tommaso; Ruzzene, Massimo; Ermanni, Paolo

    2015-10-01

    In this paper, we report on the wave transmission characteristics of a hybrid one dimensional (1D) medium. The hybrid characteristic is the result of the coupling between a 1D mechanical waveguide in the form of an elastic beam, supporting the propagation of transverse waves and a discrete electrical transmission line, consisting of a series of inductors connected to ground through capacitors. The capacitors correspond to a periodic array of piezoelectric patches that are bonded to the beam and that couple the two waveguides. The coupling leads to a hybrid medium that is characterized by a coincidence condition for the frequency/wavenumber value corresponding to the intersection of the branches of the two waveguides. In the frequency range centered at coincidence, the hybrid medium features strong attenuation of wave motion as a result of the energy transfer towards the electrical transmission line. This energy transfer, and the ensuing attenuation of wave motion, is alike the one obtained through internal resonating units of the kind commonly used in metamaterials. However, the distinct shape of the dispersion curves suggests how this energy transfer is not the result of a resonance and is therefore fundamentally different. This paper presents the numerical investigation of the wave propagation in the considered media, it illustrates experimental evidence of wave transmission characteristics and compares the performance of the considered configuration with that of internal resonating metamaterials. In addition, the ability to conveniently tune the dispersion properties of the electrical transmission line is exploited to adapt the periodicity of the domain and to investigate diatomic periodic configurations that are characterized by a richer dispersion spectrum and broader bandwidth of wave attenuation at coincidence. The medium consisting of mechanical, piezoelectric, and analog electronic elements can be easily interfaced to digital devices to offer a novel

  20. mm-Wave Hybrid Photonic Wireless Links for Ultra-High Speed Wireless Transmissions

    DEFF Research Database (Denmark)

    Rommel, Simon; Vegas Olmos, Juan José; Tafur Monroy, Idelfonso

    Hybrid photonic-wireless transmission schemes in the mm-wave frequency range are promising candidates to enable the multi-gigabit per second data communications required from wireless and mobile networks of the 5th and future generations. Large FCC spectrum allocations for wireless transmission...

  1. An adaptive metamaterial beam with hybrid shunting circuits for extremely broadband control of flexural waves

    Science.gov (United States)

    Chen, Y. Y.; Hu, G. K.; Huang, G. L.

    2016-10-01

    A great deal of research has been devoted to controlling the dynamic behaviors of phononic crystals and metamaterials by directly tuning the frequency regions and/or widths of their inherent band gaps. Here, we report a new class of adaptive metamaterial beams with hybrid shunting circuits to realize super broadband Lamb-wave band gaps at an extreme subwavelength scale. The proposed metamaterial is made of a homogeneous host beam on which tunable local resonators consisting of hybrid shunted piezoelectric stacks with proof masses are attached. The hybrid shunting circuits are composed of negative-capacitance and negative-inductance elements connected in series or in parallel in order to tune the desired frequency-dependent stiffness. It is shown theoretically and numerically that by properly modifying the shunting impedance, the adaptive mechanical mechanism within the tunable resonator can produce high-pass and low-pass wave filtering capabilities for the zeroth-order anti-symmetric Lamb-wave modes. These unique behaviors are due to the hybrid effects from the negative-capacitance and negative-inductance circuit elements. Such a system opens up important perspectives for the development of adaptive vibration or wave-attenuation devices for broadband frequency applications.

  2. Continuous-wave Optically Pumped Lasing of Hybrid Perovskite VCSEL at Green Wavelength

    KAUST Repository

    Alias, Mohd Sharizal

    2017-05-08

    We demonstrate the lasing of a perovskite vertical-cavity surface-emitting laser at green wavelengths, which operates under continuous-wave optical pumping at room-temperature by embedding hybrid perovskite between dielectric mirrors deposited at low-temperature.

  3. Observation of the lower hybrid waves near the three-dimensional null pair

    Institute of Scientific and Technical Information of China (English)

    ZHOU Meng; DENG XiaoHua; FU Song; TANG RongXin; HU YunHui; LI ShiYou; A. VAIVADS; M. ANDRE; LIN Xi; LIN MingHui; ZHOU XiaoMin

    2009-01-01

    Magnetic reconnection is a fundamental process in plasma, which is thought to play important roles both in laboratory and natural plasmas through affecting magnetic topology, heating and accelerating particles. During an event on Oct. 1st, 2001, the Cluster tetrahedron circled around the magnetic re-connection region several times, and Xiao et al. First identified the null pair and found that the spectrum of the null-point oscillation shows the maximum power near the lower-hybrid frequency. In this paper we report the observation of electromagnetic and electrostatic wave enhancements near lower hybrid frequency associated with the reconnection process near the null pair. The lower hybrid waves (LHWs) with quasi-perpendicular propagation were identified and also confirmed by the power law of the spectrum of electric and magnetic fields.

  4. Observation of the lower hybrid waves near the three-dimensional null pair

    Institute of Scientific and Technical Information of China (English)

    A.; VAIVADS; M.; ANDRE

    2009-01-01

    Magnetic reconnection is a fundamental process in plasma,which is thought to play important roles both in laboratory and natural plasmas through affecting magnetic topology,heating and accelerating particles. During an event on Oct. 1st,2001,the Cluster tetrahedron circled around the magnetic reconnection region several times,and Xiao et al. first identified the null pair and found that the spectrum of the null-point oscillation shows the maximum power near the lower-hybrid frequency. In this paper we report the observation of electromagnetic and electrostatic wave enhancements near lower hybrid frequency associated with the reconnection process near the null pair. The lower hybrid waves(LHWs) with quasi-perpendicular propagation were identified and also confirmed by the power law of the spectrum of electric and magnetic fields.

  5. Quantum electrostatic surface waves in a hybrid plasma waveguide: Effect of nano-sized slab

    Science.gov (United States)

    Shahmansouri, M.; Mahmodi Moghadam, M.

    2017-10-01

    The propagation properties of surface plasmon (SP) waves are studied in a hybrid plasma waveguide (consisting of plasma-gap-dielectric layers) with quantum effects including the Fermi-pressure, the Bohm potential and the exchange-correlation interaction. By using a quantum hydrodynamic model and Maxwell's equations, the dispersion relation of SP waves is derived, which describes the quantum corrected features of the dispersion properties of such surface waves. Previous results in this context are recovered. It is found that the exchange-correlation interactions and the presence of the second dielectric layer drastically modify the behaviors of the surface plasmon waves. The implications of our finding are discussed in some particular cases of interest. Our finding is applicable for understanding the surface wave behaviors in nano-scale systems.

  6. Hybrid yttrium iron garnet-ferromagnet structures for spin-wave devices

    Energy Technology Data Exchange (ETDEWEB)

    Papp, A., E-mail: apapp@nd.edu [Center for Nano Science and Technology and Department of Electrical Engineering, University of Notre Dame, Notre Dame, Indiana 46556 (United States); Pázmány Péter Catholic University, Faculty of Information Technology, Budapest 1088 (Hungary); Porod, W., E-mail: porod@nd.edu; Csaba, G., E-mail: gcsaba@nd.edu [Center for Nano Science and Technology and Department of Electrical Engineering, University of Notre Dame, Notre Dame, Indiana 46556 (United States)

    2015-05-07

    We study coupled ferromagnetic layers, which could facilitate low loss, sub 100 nm wavelength spin-wave propagation and manipulation. One of the layers is a low-loss garnet film (such as yttrium iron garnet (YIG)) that enables long-distance, coherent spin-wave propagation. The other layer is made of metal-based (Permalloy, Co, and CoFe) magnetoelectronic structures that can be used to generate, manipulate, and detect the spin waves. Using micromagnetic simulations, we analyze the interactions between the spin waves in the YIG and the metallic nanomagnet structures and demonstrate the components of a scalable spin-wave based signal processing device. We argue that such hybrid-metallic ferromagnet structures can be the basis of potentially high-performance, ultra low-power computing devices.

  7. Hybrid single-beam reconstruction technique for slow and fast varying wave fields.

    Science.gov (United States)

    Falaggis, Konstantinos; Kozacki, Tomasz; Kujawinska, Malgorzata

    2015-06-01

    An iterative single-beam wave field reconstruction technique that employs both non-paraxial, wave propagation based and paraxial deterministic phase retrieval techniques is presented. This approach overcomes two major obstacles that exist in the current state of the art techniques: iterative methods do not reconstruct slowly varying wave fields due to slow convergence and stagnation, and deterministic methods have paraxial limits, making the reconstructions of quickly varying object features impossible. In this work, a hybrid approach is reported that uses paraxial wave field corrections within iterative phase retrieval solvers. This technique is suitable for cases ranging from slow to fast varying wave fields, and unlike the currently available methods, can also reconstruct measurement objects with different regions of both slowly and quickly varying object features. It is further shown that this technique gives a higher accuracy than current single-beam phase retrieval techniques, and in comparison to the iterative methods, has a higher convergence speed.

  8. A hybrid method based upon nonlinear Lamb wave response for locating a delamination in composite laminates.

    Science.gov (United States)

    Yelve, Nitesh P; Mitra, Mira; Mujumdar, P M; Ramadas, C

    2016-08-01

    A new hybrid method based upon nonlinear Lamb wave response in time and frequency domains is introduced to locate a delamination in composite laminates. In Lamb wave based nonlinear method, the presence of damage is shown by the appearance of higher harmonics in the Lamb wave response. The proposed method not only uses this spectral information but also the corresponding temporal response data, for locating the delamination. Thus, the method is termed as a hybrid method. The paper includes formulation of the method and its application to locate a Barely Visible Impact Damage (BVID) induced delamination in a Carbon Fiber Reinforced Polymer (CFRP) laminate. The method gives the damage location fairly well. It is a baseline free method, as it does not need data from the pristine specimen.

  9. Paraxial Wentzel-Kramers-Brillouin method applied to the lower hybrid wave propagation

    Energy Technology Data Exchange (ETDEWEB)

    Bertelli, N.; Phillips, C. K.; Valeo, E.; Wilson, J. R. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States); Maj, O.; Poli, E. [Max Planck Institute for Plasma Physics, EURATOM Association, Boltzmannstr. 2, 85748, Garching (Germany); Harvey, R. [CompX, Del Mar, California 92014 (United States); Wright, J. C.; Bonoli, P. T. [MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139 (United States); Smirnov, A. P. [Lomonosov Moscow State University, Moscow (Russian Federation)

    2012-08-15

    The paraxial Wentzel-Kramers-Brillouin (pWKB) approximation, also called beam tracing method, has been employed in order to study the propagation of lower hybrid waves in a tokamak plasma. Analogous to the well-know ray tracing method, this approach reduces Maxwell's equations to a set of ordinary differential equations, while, in addition, retains the effects of the finite beam cross-section, and, thus, the effects of diffraction. A new code, LHBEAM (lower hybrid BEAM tracing), is presented, which solves the pWKB equations in tokamak geometry for arbitrary launching conditions and for analytic and experimental plasma equilibria. In addition, LHBEAM includes linear electron Landau damping for the evaluation of the absorbed power density and the reconstruction of the wave electric field in both the physical and Fourier space. Illustrative LHBEAM calculations are presented along with a comparison with the ray tracing code GENRAY and the full wave solver TORIC-LH.

  10. Effect of organic-inorganic hybrid P123-em-SBA15 on lithium transport properties of composite polymer electrolyte

    Institute of Scientific and Technical Information of China (English)

    XI Jingyu; HUANG Xiaobin; TANG Xiaozhen

    2004-01-01

    A novel PEO-based composite polymer electrolyte by using organic-inorganic hybrid EO20PO70EO20-em- mesoporous silica (P123-em-SBA15) as the filler has been developed. The experiment results show that P123-em- SBA15 can enhance the lithium-ion transference number of the composite polymer electrolyte, which is induced by the special topology structure of P123 in P123-em-SBA15 hybrid. In addition, room temperature ionic conductivity of the composite polymer electrolyte can also be increased by about two orders of magnitude. The excellent lithium transport properties suggest that PEO-LiClO4-P123-em-SBA15 composite polymer electrolyte can be used as electrolyte materials for all solid-state rechargeable lithium polymer batteries.

  11. EM wave propagation analysis in plasma covered radar absorbing material

    CERN Document Server

    Singh, Hema; Rawat, Harish Singh

    2017-01-01

    This book focuses on EM propagation characteristics within multilayered plasma-dielectric-metallic media. The method used for analysis is impedance transformation method. Plasma covered radar absorbing material is approximated as a multi-layered dielectric medium. The plasma is considered to be bounded homogeneous/inhomogeneous medium. The reflection coefficient and hence return loss is analytically derived. The role of plasma parameters, such as electron density, collision frequency, plasma thickness, and plasma density profile in the absorption behavior of multi-layered plasma-RAM structure is described. This book provides a clearer picture of EM propagation within plasma. The reader will get an insight of plasma parameters that play significant role in deciding the absorption characteristics of plasma covered surfaces.

  12. Influence of collisions on parametric instabilities induced by lower hybrid waves in tokamak plasmas

    Science.gov (United States)

    Castaldo, C.; Di Siena, A.; Fedele, R.; Napoli, F.; Amicucci, L.; Cesario, R.; Schettini, G.

    2016-01-01

    Parametric instabilities induced at the plasma edge by lower hybrid wave power externally coupled to tokamak plasmas have, via broadening of the antenna spectrum, strong influence on the power deposition and current drive in the core. For modeling the parametric instabilities at the tokamak plasma edge in lower hybrid current drive experiments, the effect of the collisions has been neglected so far. In the present work, a specific collisional parametric dispersion relation, useful to analyze these nonlinear phenomena near the lower hybrid antenna mouth, is derived for the first time, based on a kinetic model. Numerical solutions show that in such cold plasma regions the collisions prevent the onset of the parametric instabilities. This result is important for present lower hybrid current drive experiments, as well as in fusion reactor scenarios.

  13. Hybrid Model of Inhomogeneous Solar Wind Plasma Heating by Alfven Wave Spectrum: Parametric Studies

    Science.gov (United States)

    Ofman, L.

    2010-01-01

    Observations of the solar wind plasma at 0.3 AU and beyond show that a turbulent spectrum of magnetic fluctuations is present. Remote sensing observations of the corona indicate that heavy ions are hotter than protons and their temperature is anisotropic (T(sub perpindicular / T(sub parallel) >> 1). We study the heating and the acceleration of multi-ion plasma in the solar wind by a turbulent spectrum of Alfvenic fluctuations using a 2-D hybrid numerical model. In the hybrid model the protons and heavy ions are treated kinetically as particles, while the electrons are included as neutralizing background fluid. This is the first two-dimensional hybrid parametric study of the solar wind plasma that includes an input turbulent wave spectrum guided by observation with inhomogeneous background density. We also investigate the effects of He++ ion beams in the inhomogeneous background plasma density on the heating of the solar wind plasma. The 2-D hybrid model treats parallel and oblique waves, together with cross-field inhomogeneity, self-consistently. We investigate the parametric dependence of the perpendicular heating, and the temperature anisotropy in the H+-He++ solar wind plasma. It was found that the scaling of the magnetic fluctuations power spectrum steepens in the higher-density regions, and the heating is channeled to these regions from the surrounding lower-density plasma due to wave refraction. The model parameters are applicable to the expected solar wind conditions at about 10 solar radii.

  14. Hybrid local FEM/global LISA modeling of damped guided wave propagation in complex composite structures

    Science.gov (United States)

    Shen, Yanfeng; Cesnik, Carlos E. S.

    2016-09-01

    This paper presents a new hybrid modeling technique for the efficient simulation of guided wave generation, propagation, and interaction with damage in complex composite structures. A local finite element model is deployed to capture the piezoelectric effects and actuation dynamics of the transmitter, while the global domain wave propagation and interaction with structural complexity (structure features and damage) are solved utilizing a local interaction simulation approach (LISA). This hybrid approach allows the accurate modeling of the local dynamics of the transducers and keeping the LISA formulation in an explicit format, which facilitates its readiness for parallel computing. The global LISA framework was extended through the 3D Kelvin-Voigt viscoelasticity theory to include anisotropic damping effects for composite structures, as an improvement over the existing LISA formulation. The global LISA framework was implemented using the compute unified device architecture running on graphic processing units. A commercial preprocessor is integrated seamlessly with the computational framework for grid generation and material property allocation to handle complex structures. The excitability and damping effects are successfully captured by this hybrid model, with experimental validation using the scanning laser doppler vibrometry. To demonstrate the capability of our hybrid approach for complex structures, guided wave propagation and interaction with a delamination in a composite panel with stiffeners is presented.

  15. Hybrid Model of Inhomogeneous Solar Wind Plasma Heating by Alfven Wave Spectrum: Parametric Studies

    Science.gov (United States)

    Ofman, L.

    2010-01-01

    Observations of the solar wind plasma at 0.3 AU and beyond show that a turbulent spectrum of magnetic fluctuations is present. Remote sensing observations of the corona indicate that heavy ions are hotter than protons and their temperature is anisotropic (T(sub perpindicular / T(sub parallel) >> 1). We study the heating and the acceleration of multi-ion plasma in the solar wind by a turbulent spectrum of Alfvenic fluctuations using a 2-D hybrid numerical model. In the hybrid model the protons and heavy ions are treated kinetically as particles, while the electrons are included as neutralizing background fluid. This is the first two-dimensional hybrid parametric study of the solar wind plasma that includes an input turbulent wave spectrum guided by observation with inhomogeneous background density. We also investigate the effects of He++ ion beams in the inhomogeneous background plasma density on the heating of the solar wind plasma. The 2-D hybrid model treats parallel and oblique waves, together with cross-field inhomogeneity, self-consistently. We investigate the parametric dependence of the perpendicular heating, and the temperature anisotropy in the H+-He++ solar wind plasma. It was found that the scaling of the magnetic fluctuations power spectrum steepens in the higher-density regions, and the heating is channeled to these regions from the surrounding lower-density plasma due to wave refraction. The model parameters are applicable to the expected solar wind conditions at about 10 solar radii.

  16. VLSI Implementation of Hybrid Wave-Pipelined 2D DWT Using Lifting Scheme

    Directory of Open Access Journals (Sweden)

    G. Seetharaman

    2008-01-01

    Full Text Available A novel approach is proposed in this paper for the implementation of 2D DWT using hybrid wave-pipelining (WP. A digital circuit may be operated at a higher frequency by using either pipelining or WP. Pipelining requires additional registers and it results in more area, power dissipation and clock routing complexity. Wave-pipelining does not have any of these disadvantages but requires complex trial and error procedure for tuning the clock period and clock skew between input and output registers. In this paper, a hybrid scheme is proposed to get the benefits of both pipelining and WP techniques. In this paper, two automation schemes are proposed for the implementation of 2D DWT using hybrid WP on both Xilinx, San Jose, CA, USA and Altera FPGAs. In the first scheme, Built-in self-test (BIST approach is used to choose the clock skew and clock period for I/O registers between the wave-pipelined blocks. In the second approach, an on-chip soft-core processor is used to choose the clock skew and clock period. The results for the hybrid WP are compared with nonpipelined and pipelined approaches. From the implementation results, the hybrid WP scheme requires the same area but faster than the nonpipelined scheme by a factor of 1.25–1.39. The pipelined scheme is faster than the hybrid scheme by a factor of 1.15–1.39 at the cost of an increase in the number of registers by a factor of 1.78–2.73, increase in the number of LEs by a factor of 1.11–1.32 and it increases the clock routing complexity.

  17. Role of fast waves in the central deposition of lower hybrid power

    Science.gov (United States)

    Heikkinen, J. A.; Tala, T. J. J.; Pättikangas, T. J. H.; Piliya, A. D.; Saveliev, A. N.; Karttunen, S. J.

    1999-10-01

    In tokamaks, lower hybrid (LH) waves are routinely used for current drive and heating of plasmas. The LH waves have two modes of propagation that are called the slow and the fast wave. Usually, the lower hybrid waves are launched as slow waves into a tokamak, but during the propagation part of the wave power can be transformed to fast waves. General characteristics of the mode transformation of slow waves to fast waves are first investigated with a simple quasitoroidal ray-tracing model. Next, the effect of mode transformed LH power on the deposition profiles in a JET-like tokamak is analysed by using the fast ray-tracing code FRTC. When the launched spectrum is at small values of the toroidal refractive index (1.6 icons/Journals/Common/lesssim" ALT="lesssim" ALIGN="TOP"/> nicons/Journals/Common/phi" ALT="phi" ALIGN="TOP"/>0 icons/Journals/Common/lesssim" ALT="lesssim" ALIGN="TOP"/> 2.0), the contribution of the fast wave to the deposited power is found to be significant and responsible for most of the absorption at the centre. When nicons/Journals/Common/phi" ALT="phi" ALIGN="TOP"/>0 is large (nicons/Journals/Common/phi" ALT="phi" ALIGN="TOP"/>0 icons/Journals/Common/gtrsim" ALT="gtrsim" ALIGN="TOP"/> 2.2), the effect of the mode transformed fast waves is small or negligible. At modest central densities (ne0 ~ 0.5 × 1020 m-3), the contribution of the fast wave to the power deposition can be more than 50% in the plasma centre. In consequence, the significant amount of wave energy absorbed in the fast mode must be carefully taken into account in modelling LH current drive experiments in the future. At low central densities (ne0 icons/Journals/Common/lesssim" ALT="lesssim" ALIGN="TOP"/> 0.3 × 1020 m-3), practically no absorption of fast waves occurs.

  18. Controllable wave propagation of hybrid dispersive medium with LC high-pass network (Conference Presentation)

    Science.gov (United States)

    Flores Parra, Edgar; Bergamini, Andrea E.; Ermanni, Paolo

    2017-04-01

    This work reports on the wave transmission characteristics of a hybrid one dimensional (1D) medium. The hybrid characteristic is the result of the coupling between a mechanical waveguide in the form of an elastic beam, and an electrical network. The network configuration investigated is an LC high-pass, consisting of a series of capacitors connected in series through grounded inductors. The capacitors correspond to a periodic array of piezoelectric patches that are bonded to the beam thus coupling the two waveguides. The coupling is characterized by a coincidence frequency/wavenumber corresponding to the intersection of the dispersion curves. At this coincidence frequency, the hybrid medium features attenuation of wave motion as a result of the energy transfer to the electrical network. This energy exchange is depicted in the dispersion by eigenvalue crossing, a particular case of eigenvalue veering. This paper presents the numerical investigations of the wave propagation in the considered medium, and validates the numerical findings with experimental evidence of the wave transmission characteristics. Moreover, the dispersion properties of the electrical network are further studied by varying the inductances thus exploiting the tunability of the periodic electrical domain, i.e: monoatomic and diatmomic unit cell configurations. The LC high-pass network offers several advantages over other configurations, from ease of implementation as the piezoelectric elements are not grounded, to a smaller inductance values to achieve attenuation at a given frequency. Such media could be interfaced with more complex electrical networks to create a new type of smart materials.

  19. General Solution of EM Wave Propagation in Anisotropic Media

    CERN Document Server

    Lee, Jinyoung

    2010-01-01

    When anisotropy is involved, the wave equation becomes simultaneous partial differential equations that are not easily solved. Moreover, when the anisotropy occurs due to both permittivity and permeability, these equations are insolvable without a numerical or an approximate method. The problem is essentially due to the fact neither $\\e$ nor $\\m$ can be extracted from the curl term, when they are in it. The terms $\

  20. Influence of plasma beta on the generation of lower hybrid and whistler waves by an ion velocity ring distribution

    Energy Technology Data Exchange (ETDEWEB)

    Winske, D., E-mail: winske@lanl.gov; Daughton, W. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

    2015-02-15

    We present results of three-dimensional electromagnetic particle-in-cell simulations of the lower hybrid ion ring instability, similar to our earlier results [D. Winske and W. Daughton, Phys. Plasma 19, 072109 (2012)], but at higher electron beta (β{sub e} = ratio of electron thermal pressure to magnetic pressure = 0.06, rather than at 0.006) with T{sub i} = T{sub e}. At higher electron beta, the level of lower hybrid waves at saturation normalized to the ion thermal energy (β{sub i} = 0.06 also) is only slightly smaller, but the corresponding magnetic fluctuations are about an order of magnitude larger, consistent with linear theory. After saturation, the waves evolve into whistler waves, through a number of possible mechanisms, with an average growth rate considerably smaller than the linear growth rate of the lower hybrid waves, to a peak fluctuation level that is about 20% above the lower hybrid wave saturation level. The ratio of the peak magnetic fluctuations associated with the whistler waves relative to those of the saturated lower hybrid waves, the ratio of the nonlinear growth rate of whistlers relative to the linear growth rate of lower hybrid waves, the amount of energy extracted from the ring, and the amount of heating of the background ions and electrons are comparable to those in the lower electron beta 3D simulation. This suggests that even at higher electron beta, the linear and nonlinear physics of the lower hybrid ion ring instability is dominated by electrostatic, wave-particle rather than wave-wave interactions.

  1. Influence of plasma beta on the generation of lower hybrid and whistler waves by an ion velocity ring distribution

    Science.gov (United States)

    Winske, D.; Daughton, W.

    2015-02-01

    We present results of three-dimensional electromagnetic particle-in-cell simulations of the lower hybrid ion ring instability, similar to our earlier results [D. Winske and W. Daughton, Phys. Plasma 19, 072109 (2012)], but at higher electron beta (βe = ratio of electron thermal pressure to magnetic pressure = 0.06, rather than at 0.006) with Ti = Te. At higher electron beta, the level of lower hybrid waves at saturation normalized to the ion thermal energy (βi = 0.06 also) is only slightly smaller, but the corresponding magnetic fluctuations are about an order of magnitude larger, consistent with linear theory. After saturation, the waves evolve into whistler waves, through a number of possible mechanisms, with an average growth rate considerably smaller than the linear growth rate of the lower hybrid waves, to a peak fluctuation level that is about 20% above the lower hybrid wave saturation level. The ratio of the peak magnetic fluctuations associated with the whistler waves relative to those of the saturated lower hybrid waves, the ratio of the nonlinear growth rate of whistlers relative to the linear growth rate of lower hybrid waves, the amount of energy extracted from the ring, and the amount of heating of the background ions and electrons are comparable to those in the lower electron beta 3D simulation. This suggests that even at higher electron beta, the linear and nonlinear physics of the lower hybrid ion ring instability is dominated by electrostatic, wave-particle rather than wave-wave interactions.

  2. Upper-hybrid wave driven Alfvenic turbulence in magnetized dusty plasmas

    CERN Document Server

    Misra, A P

    2010-01-01

    The nonlinear dynamics of coupled electrostatic upper-hybrid (UH) and Alfven waves (AWs) is revisited in a magnetized electron-ion plasma with charged dust impurities. A pair of nonlinear equations [J.Plasma Phys. 73, 3 (2006)] that describe the interaction of UH wave envelopes (including the relativistic electron mass increase) and the density as well as the compressional magnetic field perturbations associated with the AWs is solved numerically to show that many coherent solitary patterns can be excited and saturated due to modulational instability of unstable UH waves. The evolution of these solitary patterns is also shown to appear in the states of spatiotemporal coherence, temporal as well as spatiotemporal chaos due to collision and fusion among the patterns in stochastic motion. Furthermore, these spatiotemporal features are demonstrated by the analysis of wavelet power spectra. It is found that a redistribution of wave energy takes place to higher harmonic modes with small wavelengths which, in turn, ...

  3. Study of lower hybrid wave propagation in ionized gas by Hamiltonian theory

    CERN Document Server

    Casolari, Andrea

    2013-01-01

    In order to find an approximate solution to the Vlasov-Maxwell equation system describing the lower hybrid wave propagation in magnetic confined plasmas, the use of the WKB method leads to the ray tracing equations. The Hamiltonian character of the ray tracing equations is investigated analytically and numerically in order to deduce the physical properties of the wave propagating without absorption in the confined plasma. The consequences of the Hamiltonian character of the equations on the travelling wave, in particular, on the evolution of the parallel wavenumber along the propagation path have been accounted and the chaotic diffusion of the timeaveraged parallel wave-number towards higher values has been evaluated. Numerical analysis by means of a Runge-Kutta based algorithm implemented in a ray tracing code supplies the analytical considerations. A numerical tool based on the symplectic integration of the ray trajectories has been developed.

  4. Study of lower hybrid wave propagation in ionized gas by Hamiltonian theory

    Energy Technology Data Exchange (ETDEWEB)

    Casolari, A. [Università di Pisa, Pisa (Italy); Cardinali, A. [Associazione Euratom-ENEA sulla Fusione, C.P. 65 - I-00044 - Frascati, Rome (Italy)

    2014-02-12

    In order to find an approximate solution to the Vlasov-Maxwell equation system describing the lower hybrid wave propagation in magnetic confined plasmas, the use of the WKB method leads to the ray tracing equations. The Hamiltonian character of the ray tracing equations is investigated analytically and numerically in order to deduce the physical properties of the wave propagating without absorption in the confined plasma. The consequences of the Hamiltonian character of the equations on the travelling wave, in particular, on the evolution of the parallel wavenumber along the propagation path have been accounted and the chaotic diffusion of the timeaveraged parallel wave-number towards higher values has been evaluated. Numerical analysis by means of a Runge-Kutta based algorithm implemented in a ray tracing code supplies the analytical considerations. A numerical tool based on the symplectic integration of the ray trajectories has been developed.

  5. Opportunistic beam training with hybrid analog/digital codebooks for mmWave systems

    KAUST Repository

    Eltayeb, Mohammed E.

    2016-02-25

    © 2015 IEEE. Millimeter wave (mmWave) communication is one solution to provide more spectrum than available at lower carrier frequencies. To provide sufficient link budget, mmWave systems will use beamforming with large antenna arrays at both the transmitter and receiver. Training these large arrays using conventional approaches taken at lower carrier frequencies, however, results in high overhead. In this paper, we propose a beam training algorithm that efficiently designs the beamforming vectors with low training overhead. Exploiting mmWave channel reciprocity, the proposed algorithm relaxes the need for an explicit feedback channel, and opportunistically terminates the training process when a desired quality of service is achieved. To construct the training beamforming vectors, a new multi-resolution codebook is developed for hybrid analog/digital architectures. Simulation results show that the proposed algorithm achieves a comparable rate to that obtained by exhaustive search solutions while requiring lower training overhead when compared to prior work.

  6. The new wave of hybrid vehicles in Japan; La nouvelle vague de vehicules hybrides au Japon

    Energy Technology Data Exchange (ETDEWEB)

    Moille, F.

    2000-05-01

    The Japan Ministry of international trade and industry (MITI) has foreseen a 23% reduction of the consumption of internal combustion engines between 1995 and 2010. The Japanese automotive companies are seriously working on the development of less polluting and more economical vehicles. After the domination of the internal combustion engine with its good performances, and the quasi-exclusive use of electric-powered vehicles in urban areas for autonomy reasons, time has come for the development of hybrid vehicles which combine the advantages of both principles. With a very simple use for the driver, the hybrid vehicle is in fact based on a particularly complex technology which is explained for some prototypes presented in this paper. (J.S.)

  7. Development of hybrid composite radar wave absorbing structure for stealth applications

    Indian Academy of Sciences (India)

    T Annil Kumar; J Inayathullah; V A Nagarajan; S Hari Kumar

    2016-02-01

    The ideally invisible stealth radomes are usually sandwiched constructions composed of E-glass/epoxy composite, polyvinyl chloride foam and frequency selective surfaces (FSS). Nylon 6/6 and balsa wood are well known for their low dielectric properties. In this work the electromagnetic (EM) wave transmission characteristics of the existing stealth radomes were improved by employing nylon 6/6 fibre and balsa wood, along with E-glass/epoxy composite without compromising the mechanical properties. The free space measurement technique was performed to measure the EM wave transmission characteristics in the X-band frequency range (8.2–12.4 GHz) for a specific FSS. The flexural strength of the sandwiched constructions were investigated with three-point bending test.

  8. A Magnetic Flux Leakage and Magnetostrictive Guided Wave Hybrid Transducer for Detecting Bridge Cables

    Directory of Open Access Journals (Sweden)

    Jiang Xu

    2012-01-01

    Full Text Available Condition assessment of cables has gained considerable attention for the bridge safety. A magnetic flux leakage and magnetostrictive guided wave hybrid transducer is provided to inspect bridge cables. The similarities and differences between the two methods are investigated. The hybrid transducer for bridge cables consists of an aluminum framework, climbing modules, embedded magnetizers and a ribbon coil. The static axial magnetic field provided by the magnetizers meets the needs of the magnetic flux leakage testing and the magnetostrictive guided wave testing. The magnetizers also provide the attraction for the climbing modules. In the magnetic flux leakage testing for the free length of cable, the coil induces the axial leakage magnetic field. In the magnetostrictive guided wave testing for the anchorage zone, the coil provides a pulse high power variational magnetic field for generating guided waves; the coil induces the magnetic field variation for receiving guided waves. The experimental results show that the transducer with the corresponding inspection system could be applied to detect the broken wires in the free length and in the anchorage zone of bridge cables.

  9. Reduction of the equation for lower hybrid waves in a plasma to a nonlinear Schroedinger equation

    Science.gov (United States)

    Karney, C. F. F.

    1977-01-01

    Equations describing the nonlinear propagation of waves in an anisotropic plasma are rarely exactly soluble. However it is often possible to make approximations that reduce the exact equations into a simpler equation. The use of MACSYMA to make such approximations, and so reduce the equation describing lower hybrid waves into the nonlinear Schrodinger equation which is soluble by the inverse scattering method is demonstrated. MACSYMA is used at several stages in the calculation only because there is a natural division between calculations that are easiest done by hand, and those that are easiest done by machine.

  10. Hybrid surface waves in semi-infinite metal-dielectric lattices

    CERN Document Server

    Miret, Juan J; Jaksic, Zoran; Vukovic, Slobodan; Belic, Milivoj R

    2012-01-01

    We investigate surface waves at the boundary between a semi-infinite layered metal-dielectric nanostructure cut normally to the layers and a semi-infinite dielectric. Spatial dispersion properties of such a nanostructure can be dramatically affected by coupling of surface plasmons polaritons at different metal-dielectric interfaces. As a consequence, the effective medium approach is not applicable in general. It is demonstrated that Dyakonov-like surface waves with hybrid polarization can propagate in an angular range substantially enlarged compared to conventional birefringent materials. Our numerical simulations for an Ag-GaAs stack in contact with glass show a low to moderate influence of losses.

  11. Strong Optomechanical Interaction in Hybrid Plasmonic-Photonic Crystal Nanocavities with Surface Acoustic Waves.

    Science.gov (United States)

    Lin, Tzy-Rong; Lin, Chiang-Hsin; Hsu, Jin-Chen

    2015-09-08

    We propose dynamic modulation of a hybrid plasmonic-photonic crystal nanocavity using monochromatic coherent acoustic phonons formed by ultrahigh-frequency surface acoustic waves (SAWs) to achieve strong optomechanical interaction. The crystal nanocavity used in this study consisted of a defective photonic crystal beam coupled to a metal surface with a nanoscale air gap in between and provided hybridization of a highly confined plasmonic-photonic mode with a high quality factor and deep subwavelength mode volume. Efficient photon-phonon interaction occurs in the air gap through the SAW perturbation of the metal surface, strongly coupling the optical and acoustic frequencies. As a result, a large modulation bandwidth and optical resonance wavelength shift for the crystal nanocavity are demonstrated at telecommunication wavelengths. The proposed SAW-based modulation within the hybrid plasmonic-photonic crystal nanocavities beyond the diffraction limit provides opportunities for various applications in enhanced sound-light interaction and fast coherent acoustic control of optomechanical devices.

  12. Topology optimization of bounded acoustic problems using the hybrid finite element-wave based method

    DEFF Research Database (Denmark)

    Goo, Seongyeol; Wang, Semyung; Kook, Junghwan

    2017-01-01

    This paper presents an alternative topology optimization method for bounded acoustic problems that uses the hybrid finite element-wave based method (FE-WBM). The conventional method for the topology optimization of bounded acoustic problems is based on the finite element method (FEM), which...... is limited to low frequency applications due to considerable computational efforts. To this end, we propose a gradient-based topology optimization method that uses the hybrid FE-WBM whereby the entire domain of a problem is partitioned into design and non-design domains. In this respect, the FEM is used...... as a design domain of topology optimization, and the WBM is used as a non-design domain to increase computational efficiency. The adjoint variable method based on the hybrid FE-WBM is also proposed as a means of computing design sensitivities. Numerical examples are presented to demonstrate the effectiveness...

  13. On the possibility of reducing the instability threshold of a parametric decay of an extraordinary wave into two upper hybrid waves in an inhomogeneous plasma

    Energy Technology Data Exchange (ETDEWEB)

    Popov, A. Yu., E-mail: a.popov@mail.ioffe.ru; Gusakov, E. Z., E-mail: evgeniy.gusakov@mail.ioffe.ru [Russian Academy of Sciences, Ioffe Physical Technical Institute (Russian Federation)

    2015-01-15

    A parametric decay instability (PDI) of an extraordinary wave leading to excitation of two upper hybrid (UH) plasmons at frequencies close to half the pump wave frequency is analyzed. It is shown that the two-plasmon PDI power threshold can be significantly reduced under conditions of electron cyclotron resonance heating (ECRH) experiments in toroidal magnetic devices, where the plasma density profile is often nonmonotonic, which leads to the localization of UH waves.

  14. Suitability of post-Newtonian/numerical-relativity hybrid waveforms for gravitational wave detectors

    Energy Technology Data Exchange (ETDEWEB)

    MacDonald, Ilana; Nissanke, Samaya; Pfeiffer, Harald P, E-mail: macdonald@astro.utoronto.ca [Canadian Institute for Theoretical Astrophysics, University of Toronto, Toronto, Ontario M5S 3H8 (Canada)

    2011-07-07

    This paper presents a study of the sufficient accuracy of post-Newtonian and numerical relativity waveforms for the most demanding usage case: parameter estimation of strong sources in advanced gravitational wave detectors. For black hole binaries, these detectors require accurate waveform models which can be constructed by fusing an analytical post-Newtonian inspiral waveform with a numerical relativity merger-ringdown waveform. We perform a comprehensive analysis of errors that enter such 'hybrid waveforms'. We find that the post-Newtonian waveform must be aligned with the numerical relativity waveform to exquisite accuracy, about 1/100 of a gravitational wave cycle. Phase errors in the inspiral phase of the numerical relativity simulation must be controlled to {approx}< 0.1 rad. (These numbers apply to moderately optimistic estimates about the number of GW sources; exceptionally strong signals require even smaller errors.) The dominant source of error arises from the inaccuracy of the investigated post-Newtonian Taylor approximants. Using our error criterion, even at 3.5th post-Newtonian order, hybridization has to be performed significantly before the start of the longest currently available numerical waveforms which cover 30 gravitational wave cycles. The current investigation is limited to the equal-mass, zero-spin case and does not take into account calibration errors of the gravitational wave detectors.

  15. Theoretical and FEM analysis of suspension and propulsion system with HTS hybrid electromagnets in an EMS Maglev model

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Y.D., E-mail: ydchung@suwon.ac.kr [Department of Electrical Engineering, Suwon University, Bongdang Eup, Hwaseong Si 445-743 (Korea, Republic of); Lee, C.Y. [Korea Railroad Research Institute, Woram Dong, Uiwang Si 437-757 (Korea, Republic of); Jang, J.Y. [Department of Electrical Engineering, Ansan College of Technology, Choji-Dong, Ansan Si 425-792 (Korea, Republic of); Yoon, Y.S. [Department of Electrical and Electronic Engineering, Yonsei University, Sinchon-dong, Seoul 120-749 (Korea, Republic of); Ko, T.K. [Department of Electrical Engineering, Ansan College of Technology, Choji-Dong, Ansan Si 425-792 (Korea, Republic of)

    2011-11-15

    We examine levitation and propulsion forces of the proto-type maglev vehicle system based on 3D FEM. The levitation force increases over 15% due to AC current of the guideway. The levitation force by HTS electromagnet (EM) and AC current is larger over 30% than that of only HTS EM. We have been constructed a proto-type electromagnetic suspension (EMS) based maglev vehicle system. The maglev concept utilizes magnetic forces for noncontact suspension, guidance and propulsion. The suspension system with high temperature superconducting (HTS) hybrid electromagnet (EM) is composed of HTS coils and normal coils, which consume little power to keep large suspension gap. The magnetic forces realize to guide the vehicle, propel the vehicle along the guide-way and assist in braking action. The proto-type EMS-based Maglev model is designed to keep the suspension gap of 20 mm. This paper presents the theoretical analysis of the maglev vehicle based on the EMS model to obtain the designing parameters for levitation and propulsion forces. The magnetic field distributions of the electromagnetic forces with hybrid EM and propulsion stator coils are analyzed based on three dimension (3D) finite element method (FEM) analysis. From the simulation results, appropriately design parameters of the suspension, guidance and propulsion were obtained.

  16. Generation of acoustic terahertz waves in hybrid InGaN/GaN quantum wells

    Science.gov (United States)

    Mahat, Meg; Llopis, Antonia; Choi, Tae Youl; Periera, Sergio; Watson, Ian; Neogi, Arup

    2015-03-01

    We have carried out differential transmission measurements on InGaN/ GaN quantum wells with Au nanoparticles inserted inside V-pits with high filling fraction. We have observed acoustic wave packets generated with multiple THz frequencies as 0.12 THz from GaN buffer layer, 0.22 THz from Au-InGaN multiple quantum wells region, 0.07 THz from sapphire substrate, and 0.17 THz mixed signals from the sample. These THz wave packets are observed as a result of generation of coherent acoustic phonons propagating in hybrid Au-InGaN quantum wells. The study of these acoustic THz wave generation is crucial for the imaging of nanostructures.

  17. Direct detection of lower hybrid wave using a reflectometer on Alcator C-Moda)

    Science.gov (United States)

    Shiraiwa, S.; Baek, S.; Dominguez, A.; Marmar, E.; Parker, R.; Kramer, G. J.

    2010-10-01

    The possibility of directly detecting a density perturbation produced by lower hybrid (LH) waves using a reflectometer is presented. We investigate the microwave scattering of reflectometer probe beams by a model density fluctuation produced by short wavelength LH waves in an Alcator C-Mod experimental condition. In the O-mode case, the maximum response of phase measurement is found to occur when the density perturbation is approximately centimeters in front of the antenna, where Bragg scattering condition is satisfied. In the X-mode case, the phase measurement is predicted to be more sensitive to the density fluctuation close to the cut-off layer. A feasibility test was carried out using a 50 GHz O-mode reflectometer on the Alcator C-Mod tokamak, and positive results including the detection of 4.6 GHz pump wave and parametric decay instabilities were obtained.

  18. Single-Particle Cryo-EM and 3D Reconstruction of Hybrid Nanoparticles with Electron-Dense Components.

    Science.gov (United States)

    Yu, Guimei; Yan, Rui; Zhang, Chuan; Mao, Chengde; Jiang, Wen

    2015-10-01

    Single-particle cryo-electron microscopy (cryo-EM), accompanied with 3D reconstruction, is a broadly applicable tool for the structural characterization of macromolecules and nanoparticles. Recently, the cryo-EM field has pushed the limits of this technique to higher resolutions and samples of smaller molecular mass, however, some samples still present hurdles to this technique. Hybrid particles with electron-dense components, which have been studied using single-particle cryo-EM yet with limited success in 3D reconstruction due to the interference caused by electron-dense elements, constitute one group of such challenging samples. To process such hybrid particles, a masking method is developed in this work to adaptively remove pixels arising from electron-dense portions in individual projection images while maintaining maximal biomass signals for subsequent 2D alignment, 3D reconstruction, and iterative refinements. As demonstrated by the success in 3D reconstruction of an octahedron DNA/gold hybrid particle, which has been previously published without a 3D reconstruction, the devised strategy that combines adaptive masking and standard single-particle 3D reconstruction approach has overcome the hurdle of electron-dense elements interference, and is generally applicable to cryo-EM structural characterization of most, if not all, hybrid nanomaterials with electron-dense components.

  19. Nonlinear coupling of lower hybrid waves to the kinetic low-frequency plasma response in the auroral ionosphere

    Science.gov (United States)

    Sanbonmatsu, K. Y.; Goldman, M. V.; Newman, D. L.

    A hybrid kinetic-fluid model is developed which is relevant to lower hybrid spikelets observed in the topside auroral ionosphere [Vago et al., 1992; Eriksson et al., 1994]. In contrast to previous fluid models [Shapiro et al., 1995; Tam and Chang, 1995; Seyler, 1994; Shapiro et al., 1993] our linear low frequency plasma response is magnetized and kinetic. Fluid theory is used to incorporate the nonlinear wave coupling. Performing a linear stability analysis, we calculate the growth rate for the modulational instability, driven by a lower hybrid wave pump. We find that both the magnetic and kinetic effects inhibit the modulational instability.

  20. Intermodal and cross-polarization four-wave mixing in large-core hybrid photonic crystal fibers

    DEFF Research Database (Denmark)

    Petersen, Sidsel Rübner; Alkeskjold, Thomas Tanggaard; Olausson, Christina Bjarnal Thulin;

    2015-01-01

    Degenerate four-wave mixing is considered in large mode area hybrid photonic crystal fibers, combining photonic bandgap guidance and index guidance. Co- and orthogonally polarized pump, signal and idler fields are considered numerically by calculating the parametric gain and experimentally...... by spontaneous degenerate four-wave mixing. Intermodal and birefringence assisted intramodal phase matching is observed. Good agreement between calculations and experimental observations is obtained. Intermodal four-wave mixing is achieved experimentally with a conversion efficiency of 17%. (C) 2015 Optical...

  1. Intermodal and cross-polarization four-wave mixing in large-core hybrid photonic crystal fibers.

    Science.gov (United States)

    Petersen, Sidsel R; Alkeskjold, Thomas T; Olausson, Christina B; Lægsgaard, Jesper

    2015-03-09

    Degenerate four-wave mixing is considered in large mode area hybrid photonic crystal fibers, combining photonic bandgap guidance and index guidance. Co- and orthogonally polarized pump, signal and idler fields are considered numerically by calculating the parametric gain and experimentally by spontaneous degenerate four-wave mixing. Intermodal and birefringence assisted intramodal phase matching is observed. Good agreement between calculations and experimental observations is obtained. Intermodal four-wave mixing is achieved experimentally with a conversion efficiency of 17%.

  2. The Nonlinear Coupling of Electromagnetic Ion Cyclotron and Lower Hybrid Waves in the Ring Current Region

    Science.gov (United States)

    Khazanov, G. V.

    2004-01-01

    The excitation of lower hybrid waves (LHWs) is a widely discussed mechanism of interaction between plasma species in space, and is one of the unresolved questions of magnetospheric multi-ion plasmas. In this paper we present the morphology, dynamics, and level of LHW activity generated by electromagnetic ion cyclotron (EMIC) waves during the May 2-7, 1998 storm period on the global scale. The LHWs were calculated based on a newly developed self-consistent model (Khazanov et. al., 2002, 2003) that couples the system of two kinetic equations: one equation describes the ring current (RC) ion dynamic, and another equation describes the evolution of EMIC waves. It is found that the LHWs are excited by helium ions due to their mass dependent drift in the electric field of EMIC waves. The level of LHW activity is calculated assuming that the induced scattering process is the main saturation mechanism for these waves. The calculated LHWs electric fields are consistent with the observational data.

  3. Experimental characteristics of a lower hybrid wave multi-junction coupler in the HT-7 tokamak

    Institute of Scientific and Technical Information of China (English)

    Ding Bo-Jiang; Jiang Min; Zhang Gong-Rang; Huang Feng; Zhao Yan-Ping; Kuang Guang-Li; HT-7 team; Shan Jia-Fang; Liu Fu-Kun; Fang Yu-De; Wei Wei; Wu Zhen-Wei; Chen Zhong-Yong; Xu Han-Dong; Wang Mao

    2006-01-01

    A phase-controlled lower hybrid wave (LHW) multi-junction (M J) coupler (3(rows)×4(columns)×4 (subwaveguides)) has been developed in the HT-7 tokamak. Simulations show that it is more effective for driving plasma current than an ordinary phase-controlled LHW antenna (3(rows)× 12(columns)) (traditional coupler). The plasma-wave coupling experiments show that the reflection coefficient (RC) is below 10%, implying that the MJ grill can launch the wave into the plasma effectively. The effect of power spectrum launched by the MJ coupler on RC indicates that an optimal condition is requisite for a better coupling in the lower hybrid current drive (LHCD) experiments. Studies indicate that the drive efficiency of the MJ antenna is higher than that of the traditional one, which is mainly ascribed to the discrepancy in impurity concentration, plasma temperature, and spectrum directivity. An improved confinement with an electron internal transport barrier is obtained by LHCD. The analysis shows that the modified negative (low)magnetic shear and the change of radial electric field profile due to LHCD are possible factors responsible for the eITB formation.

  4. Employing injection-locked FP LDs to set up a hybrid CATV/MW/MMW WDM light wave transmission system.

    Science.gov (United States)

    Lin, Chun-Yu; Lu, Hai-Han; Li, Chung-Yi; Wu, Po-Yi; Peng, Peng-Chun; Jhang, Tai-Wei; Lin, Che-Yu

    2014-07-01

    A hybrid cable television (CATV)/microwave (MW)/millimeter-wave (MMW) wavelength-division-multiplexing (WDM) light wave transmission system based on injection-locked Fabry-Perot laser diodes (FP LDs) is proposed and demonstrated. Different from conventional hybrid WDM light wave transmission systems, which need wavelength-selected distributed feedback laser diodes to support various services, the proposed systems employ injection-locked FP LDs to provide multiple applications. Over a 40 km single-mode fiber transport, impressive performances of carrier-to-noise ratio/composite second-order/composite triple-beat/bit error rate are obtained for 550 MHz CATV/20 GHz MW/40 GHz MMW/60 GHz MMW signal transmissions. Such a hybrid WDM light wave transmission system would be attractive for fiber links to provide broadband integrated services.

  5. Abortive and propagating intracellular calcium waves: analysis from a hybrid model.

    Directory of Open Access Journals (Sweden)

    Nara Guisoni

    Full Text Available The functional properties of inositol(1,4,5-triphosphate (IP3 receptors allow a variety of intracellular Ca(2+ phenomena. In this way, global phenomena, such as propagating and abortive Ca(2+ waves, as well as local events such as puffs, have been observed. Several experimental studies suggest that many features of global phenomena (e.g., frequency, amplitude, speed wave depend on the interplay of biophysical processes such as diffusion, buffering, efflux and influx rates, which in turn depend on parameters such as buffer concentration, Ca(2+ pump density, cytosolic IP3 level, and intercluster distance. Besides, it is known that cells are able to modify some of these parameters in order to regulate the Ca(2+ signaling. By using a hybrid model, we analyzed different features of the hierarchy of calcium events as a function of two relevant parameters for the calcium signaling, the intercluster distance and the pump strength or intensity. In the space spanned by these two parameters, we found two modes of calcium dynamics, one dominated by abortive calcium waves and the other by propagating waves. Smaller distances between the release sites promote propagating calcium waves, while the increase of the efflux rate makes the transition from propagating to abortive waves occur at lower values of intercluster distance. We determined the frontier between these two modes, in the parameter space defined by the intercluster distance and the pump strength. Furthermore, we found that the velocity of simulated calcium waves accomplishes Luther's law, and that an effective rate constant for autocatalytic calcium production decays linearly with both the intercluster distance and the pump strength.

  6. Simulation of mode conversion process from upper-hybrid waves to LO-mode waves in the vicinity of the plasmapause

    Directory of Open Access Journals (Sweden)

    M. J. Kalaee

    2010-06-01

    Full Text Available In order to clarify the role of the mode conversion process in the generation mechanism of LO-mode waves in the equatorial region of the plasmasphere, we have investigated the linear mode conversion process among upper-hybrid-resonance (UHR-mode, Z-mode and LO-mode waves by a numerical simulation solving Maxwell's equations and the equation of motion of a cold electron fluid. The wave coupling process occurring in the cold magnetized plasma are examined in detail. In order to give a realistic initial plasma condition in the numerical experiments, we use initial parameters inferred from observation data obtained around the generation region of LO-mode waves obtained by the Akebono satellite. A density gradient is estimated from the observed UHR frequency, and wave normal angles are estimated from the dispersion relation of cold plasma by comparing observed wave electric fields. Then, we perform numerical experiments of mode conversion processes using the density gradient of background plasma and the wave normal angle of incident upper hybrid mode waves determined from the observation results. We found that the characteristics of reproduced LO-mode waves in each simulation run are consistent with observations.

  7. Wave dispersion in the hybrid-Vlasov model: verification of Vlasiator

    CERN Document Server

    Kempf, Yann; von Alfthan, Sebastian; Vaivads, Andris; Palmroth, Minna; Koskinen, Hannu E J

    2013-01-01

    Vlasiator is a new hybrid-Vlasov plasma simulation code aimed at simulating the entire magnetosphere of the Earth. The code treats ions (protons) kinetically through Vlasov's equation in the six-dimensional phase space while electrons are a massless charge-neutralizing fluid [M. Palmroth et al., Journal of Atmospheric and Solar-Terrestrial Physics 99, 41 (2013); A. Sandroos et al., Parallel Computing 39, 306 (2013)]. For first global simulations of the magnetosphere, it is critical to verify and validate the model by established methods. Here, as part of the verification of Vlasiator, we characterize the low-\\beta\\ plasma wave modes described by this model and compare with the solution computed by the Waves in Homogeneous, Anisotropic Multicomponent Plasmas (WHAMP) code [K. R\\"onnmark, Kiruna Geophysical Institute Reports 179 (1982)], using dispersion curves and surfaces produced with both programs. The match between the two fundamentally different approaches is excellent in the low-frequency, long wavelength...

  8. Excitation of ion-cyclotron harmonic waves in lower-hybrid heating

    Science.gov (United States)

    Villalon, E.

    1981-06-01

    The parametric excitation of ion-cyclotron waves by a lower-hybrid pump field is studied in the assumption that the magnitude of the pump is constant. The spatial amplification factor is given as a function of the wavenumber mismatch as produced by the plasma density gradient, and of the linear damping rates of the excited ion-cyclotron and sideband waves. The analysis is applied to plasma edge parameters relevant to the JFT2 heating experiment. It is found that ion-cyclotron harmonic modes are excited depending on pump frequency and plasma density. These modes are shown to have finite damping rates. The parallel refractive indices n1z of the excited sideband fields are found to be always larger than that of the driven pump field. Transition to quasi-mode decay occurs either by decreasing the pump frequency or by increasing the applied RF-power.

  9. Hybrid electrodynamics and kinetics simulation for electromagnetic wave propagation in weakly ionized hydrogen plasmas.

    Science.gov (United States)

    Chen, Qiang; Chen, Bin

    2012-10-01

    In this paper, a hybrid electrodynamics and kinetics numerical model based on the finite-difference time-domain method and lattice Boltzmann method is presented for electromagnetic wave propagation in weakly ionized hydrogen plasmas. In this framework, the multicomponent Bhatnagar-Gross-Krook collision model considering both elastic and Coulomb collisions and the multicomponent force model based on the Guo model are introduced, which supply a hyperfine description on the interaction between electromagnetic wave and weakly ionized plasma. Cubic spline interpolation and mean filtering technique are separately introduced to solve the multiscalar problem and enhance the physical quantities, which are polluted by numerical noise. Several simulations have been implemented to validate our model. The numerical results are consistent with a simplified analytical model, which demonstrates that this model can obtain satisfying numerical solutions successfully.

  10. Hybrid metal-dielectric, slow wave structure with magnetic coupling and compensation

    Energy Technology Data Exchange (ETDEWEB)

    Smirnov, A.V., E-mail: asmirnov@radiabeam.com [RadiaBeam Systems LLC, 1713 Stewart St., Santa Monica, CA 90404 (United States); Savin, E. [RadiaBeam Systems LLC, 1713 Stewart St., Santa Monica, CA 90404 (United States); National Research Nuclear University “MEPhI”, Moscow 115409 (Russian Federation)

    2016-06-01

    A number of electron beam vacuum devices such as small radiofrequency (RF) linear accelerators (linacs) and microwave traveling wave tubes (TWTs) utilize slow wave structures which are usually rather complicated in production and may require multi-step brazing and time consuming tuning. Fabrication of these devices becomes challenging at centimeter wavelengths, at large number of cells, and when a series or mass production of such structures is required. A hybrid, metal-dielectric, periodic structure for low gradient, low beam current applications is introduced here as a modification of Andreev’s disk-and-washer (DaW) structure. Compensated type of coupling between even and odd TE01 modes in the novel structure results in negative group velocity with absolute values as high as 0.1c–0.2c demonstrated in simulations. Sensitivity to material imperfections and electrodynamic parameters of the disk-and-ring (DaR) structure are considered numerically using a single cell model.

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

    Institute of Scientific and Technical Information of China (English)

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

    2005-01-01

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

  12. Effectiveness of emWave biofeedback in improving heart rate variability reactivity to and recovery from stress.

    Science.gov (United States)

    Whited, Amanda; Larkin, Kevin T; Whited, Matthew

    2014-06-01

    The current study examined the efficacy of heart rate variability (HRV) biofeedback using emWave, a publicly available biofeedback device, to determine whether training affected physiological tone and stress responses. Twenty-seven individuals aged 18-30 years were randomized to a treatment or no-treatment control group. Treatment participants underwent 4-8 sessions of emWave intervention, and all participants attended pre-treatment and post-treatment assessment sessions during which acute stressors were administered. Physiological data were collected at rest, during stress, and following stress. emWave treatment did not confer changes in tonic measures of HRV or in HRV recovery following stress. However, treatment participants exhibited higher parasympathetic responses (i.e., pNN50) during stress presentations at the post-treatment session than their control counterparts. No treatment effects were evident on self-reported measures of stress, psychological symptoms, or affect. Overall, results from the current study suggest that the emWave may confer some limited treatment effects by increasing HRV during exposure to stress. Additional development and testing of the emWave treatment protocol is necessary before it can be recommended for regular use in clinical settings, including the determination of what physiological changes are clinically meaningful during HRV biofeedback training.

  13. A Simple FDTD Algorithm for Simulating EM-Wave Propagation in General Dispersive Anisotropic Material

    KAUST Repository

    Al-Jabr, Ahmad Ali

    2013-03-01

    In this paper, an finite-difference time-domain (FDTD) algorithm for simulating propagation of EM waves in anisotropic material is presented. The algorithm is based on the auxiliary differential equation and the general polarization formulation. In anisotropic materials, electric fields are coupled and elements in the permittivity tensor are, in general, multiterm dispersive. The presented algorithm resolves the field coupling using a formulation based on electric polarizations. It also offers a simple procedure for the treatment of multiterm dispersion in the FDTD scheme. The algorithm is tested by simulating wave propagation in 1-D magnetized plasma showing excellent agreement with analytical solutions. Extension of the algorithm to multidimensional structures is straightforward. The presented algorithm is efficient and simple compared to other algorithms found in the literature. © 2012 IEEE.

  14. Electromagnetic wave absorption properties of barium titanate/carbon nanotube hybrid nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Melvin, Gan Jet Hong [Interdisciplinary Graduate School of Science and Technology, Shinshu University, Tokida, Ueda 386-8576 (Japan); Ni, Qing-Qing, E-mail: niqq@shinshu-u.ac.jp [Department of Functional Machinery and Mechanics, Shinshu University, Tokida, Ueda 386-8576 (Japan); Key Laboratory of Advanced Textile Materials and Manufacturing Technology, Ministry of Education, Zhejiang Sci-Tech University, Hangzhou (China); Natsuki, Toshiaki [Department of Functional Machinery and Mechanics, Shinshu University, Tokida, Ueda 386-8576 (Japan)

    2014-12-05

    Highlights: • BTO/CNT hybrid nanocomposites was prepared by sol–gel method. • BTO/CNT 60 wt.%, t = 1.1 mm showed a minimum reflection loss of ∼−56.5 dB. • Weight fraction and thickness can be manipulated for various absorption bands. - Abstract: Barium titanate/carbon nanotube (BTO/CNT) hybrid nanocomposites were fabricated by sol–gel method. The BTO/CNT hybrid nanomaterials were characterized using X-ray diffraction, transmission electron microscopy, field emission scanning electron microscopy, Raman and X-ray photoelectron spectroscopy. The BTO/CNT hybrid nanomaterials were then loaded in paraffin wax with different weight percentage, and pressed into toroidal shape with thickness of 1.0 mm to evaluate their complex permittivity and complex permeability using vector network analyzer. The reflection loss of the samples was calculated according to their measured complex permittivity and permeability. The minimum reflection loss of the BTO/CNT 60 wt.% hybrid nanocomposites sample with a thickness of 1.0 mm reached 29.6 dB (over 99.9% absorption) at 13.6 GHz, and also exhibited a wide response bandwidth where the frequency bandwidth of the reflection loss of less than −10 dB (over 90% absorption) was from 12.1 to 13.8 GHz. The BTO/CNT 60 wt.% hybrid nanocomposites with thickness of 1.1 mm showed a minimum reflection loss of ∼−56.5 dB (over 99.999% absorption) at 13.2 GHz and was the best absorber when compared with the other samples of different thickness. The reflection loss peak shifted to lower frequency and wider response bandwidth can be obtained as the thickness of the samples increased. The capability to modulate the absorption band of these samples to suit various applications in different frequency bands simply by manipulating their weight percentage and thickness indicates that these hybrid nanocomposites could be a promising electromagnetic wave absorber.

  15. Time-domain hybrid method for simulating large amplitude motions of ships advancing in waves

    Directory of Open Access Journals (Sweden)

    Shukui Liu

    2011-03-01

    Full Text Available Typical results obtained by a newly developed, nonlinear time domain hybrid method for simulating large amplitude motions of ships advancing with constant forward speed in waves are presented. The method is hybrid in the way of combining a time-domain transient Green function method and a Rankine source method. The present approach employs a simple double integration algorithm with respect to time to simulate the free-surface boundary condition. During the simulation, the diffraction and radiation forces are computed by pressure integration over the mean wetted surface, whereas the incident wave and hydrostatic restoring forces/moments are calculated on the instantaneously wetted surface of the hull. Typical numerical results of application of the method to the seakeeping performance of a standard containership, namely the ITTC S175, are herein presented. Comparisons have been made between the results from the present method, the frequency domain 3D panel method (NEWDRIFT of NTUA-SDL and available experimental data and good agreement has been observed for all studied cases between the results of the present method and comparable other data.

  16. Development of a hybrid wave based-transfer matrix model for sound transmission analysis.

    Science.gov (United States)

    Dijckmans, A; Vermeir, G

    2013-04-01

    In this paper, a hybrid wave based-transfer matrix model is presented that allows for the investigation of the sound transmission through finite multilayered structures placed between two reverberant rooms. The multilayered structure may consist of an arbitrary configuration of fluid, elastic, or poro-elastic layers. The field variables (structural displacements and sound pressures) are expanded in terms of structural and acoustic wave functions. The boundary and continuity conditions in the rooms determine the participation factors in the pressure expansions. The displacement of the multilayered structure is determined by the mechanical impedance matrix, which gives a relation between the pressures and transverse displacements at both sides of the structure. The elements of this matrix are calculated with the transfer matrix method. First, the hybrid model is numerically validated. Next a comparison is made with sound transmission loss measurements of a hollow brick wall and a sandwich panel. Finally, numerical simulations show the influence of structural damping, room dimensions and plate dimensions on the sound transmission loss of multilayered structures.

  17. Feedback control of current drive by using hybrid wave in tokamaks; Asservissement de la generation de courant par l`onde hybride dans un plasma de tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Wijnands, T.J. [Association Euratom-CEA, Centre d`Etudes Nucleaires de Cadarache, 13 - Saint-Paul-lez-Durance (France). Dept. de Recherches sur la Fusion Controlee]|[CEA Centre d`Etudes de Cadarache, 13 - Saint-Paul-lez-Durance (France). Direction des Sciences de la Matiere

    1997-03-01

    This work is focussed on an important and recent development in present day Controlled Nuclear Fusion Research and Tokamaks. The aim is to optimise the energy confinement for a certain magnetic configuration by adapting the radial distribution of the current. Of particular interest are feedback control scenarios with stationary modifications of the current profile using current, driven by Lower Hybrid waves. A new feedback control system has been developed for Tore Supra and has made a large number of new operation scenarios possible. In one of the experiments described here, there is no energy exchange between the poloidal field system and the plasma, the current is controlled by the power of the Lower Hybrid waves while the launched wave spectrum is used to optimise the current profile shape and the energy confinement. (author) 151 refs.

  18. Envelope Soliton in Multi-ion Plasma and Ion-Ion Hybrid Wave Excited by Energetic Electron Beam

    Institute of Scientific and Technical Information of China (English)

    WANG De-Yu; HUANG Guang-Li

    2001-01-01

    Another envelope soliton event below the H+ gyrofrequency and localized density depletion has been discoveredin the low auroral region (~1760 kin) by the Freja satellite. This envelope soliton has a characteristic frequencyat ~190 Hz, which is also close to the resonance frequency of hydrogen ion-oxygen ion hybrid wave. This event iscorrelated in time with the observations of the sharp increase of the ratio of oxygen ion density to hydrogen andwith the electron energization along the magnetic field. A theoretical model on the ion-ion hybrid wave excitedby an energetic electron beam has also been presented. It is found that the ion-ion hybrid wave is mainly excitedby the Cherenkov instability in the auroral region.

  19. An efficient hybrid pseudospectral/finite-difference scheme for solving the TTI pure P-wave equation

    KAUST Repository

    Zhan, Ge

    2013-02-19

    The pure P-wave equation for modelling and migration in tilted transversely isotropic (TTI) media has attracted more and more attention in imaging seismic data with anisotropy. The desirable feature is that it is absolutely free of shear-wave artefacts and the consequent alleviation of numerical instabilities generally suffered by some systems of coupled equations. However, due to several forward-backward Fourier transforms in wavefield updating at each time step, the computational cost is significant, and thereby hampers its prevalence. We propose to use a hybrid pseudospectral (PS) and finite-difference (FD) scheme to solve the pure P-wave equation. In the hybrid solution, most of the cost-consuming wavenumber terms in the equation are replaced by inexpensive FD operators, which in turn accelerates the computation and reduces the computational cost. To demonstrate the benefit in cost saving of the new scheme, 2D and 3D reverse-time migration (RTM) examples using the hybrid solution to the pure P-wave equation are carried out, and respective runtimes are listed and compared. Numerical results show that the hybrid strategy demands less computation time and is faster than using the PS method alone. Furthermore, this new TTI RTM algorithm with the hybrid method is computationally less expensive than that with the FD solution to conventional TTI coupled equations. © 2013 Sinopec Geophysical Research Institute.

  20. Lower hybrid frequency range waves generated by ion polarization drift due to electromagnetic ion cyclotron waves: Analysis of an event observed by the Van Allen Probe B

    Science.gov (United States)

    Khazanov, G. V.; Boardsen, S.; Krivorutsky, E. N.; Engebretson, M. J.; Sibeck, D.; Chen, S.; Breneman, A.

    2017-01-01

    We analyze a wave event that occurred near noon between 07:03 and 07:08 UT on 23 February 2014 detected by the Van Allen Probes B spacecraft, where waves in the lower hybrid frequency range (LHFR) and electromagnetic ion cyclotron (EMIC) waves are observed to be highly correlated, with Pearson correlation coefficient of 0.86. We assume that the correlation is the result of LHFR wave generation by the ions' polarization drift in the electric field of the EMIC waves. To check this assumption the drift velocities of electrons and H+, He+, and O+ ions in the measured EMIC wave electric field were modeled. Then the LHFR wave linear instantaneous growth rates for plasma with these changing drift velocities and different plasma compositions were calculated. The time distribution of these growth rates, their frequency distribution, and the frequency dependence of the ratio of the LHFR wave power spectral density (PSD) parallel and perpendicular to the ambient magnetic field to the total PSD were found. These characteristics of the growth rates were compared with the corresponding characteristics of the observed LHFR activity. Reasonable agreement between these features and the strong correlation between EMIC and LHFR energy densities support the assumption that the LHFR wave generation can be caused by the ions' polarization drift in the electric field of an EMIC wave.

  1. Analysis of Hybrid-Integrated High-Speed Electro-Absorption Modulated Lasers Based on EM/Circuit Co-simulation

    DEFF Research Database (Denmark)

    Johansen, Tom Keinicke; Krozer, Viktor; Kazmierski, C.

    2009-01-01

    An improved electromagnetic simulation (EM) based approach has been developed for optimization of the electrical to optical (E/O) transmission properties of integrated electro-absorption modulated lasers (EMLs) aiming at 100 Gbit/s Ethernet applications. Our approach allows for an accurate analys...... of the EML performance in a hybrid microstrip assembly. The established EM-based approach provides a design methodology for the future hybrid integration of the EML with its driving electronics....

  2. Formation of lower-hybrid solitary structures by modulational interaction between lower-hybrid and dispersive Alfvén waves

    Directory of Open Access Journals (Sweden)

    J. O. Hall

    2009-03-01

    Full Text Available We investigate the possibility that lower-hybrid solitary structures (LHSS, which are frequently observed in the Earth's ionosphere and magnetosphere, are formed as a result of a modulational interaction between lower-hybrid and dispersive Alfvén waves of initially small amplitude. A large amplitude lower-hybrid pump wave can excite density structures with length scales transverse to the geomagnetic field of the order of the ion gyroradius via a modulational instability. The structure formation in the nonlinear stage of the instability is investigated by numerical solutions of the governing equations, using plasma parameters relevant for LHSS observations in the upper ionosphere and in the magnetosphere. The numerical solutions reveal that the lower-hybrid waves become self-localized inside cylindrically symmetric (with respect to the ambient magnetic field density cavities, in qualitative agreement with observations. Our model includes thermal electron effects but shows no stabilization at the ion sound gyroradius, suggesting that any preference of observed LHSS for that perpendicular scale likely is due to processes arresting the cavity collapse.

  3. A hybrid stimulation strategy for suppression of spiral waves in cardiac tissue

    Energy Technology Data Exchange (ETDEWEB)

    Xu Binbin, E-mail: xubinbin@hotmail.fr [LE2I, CNRS UMR 5158, Universite de Bourgogne, Dijon (France); Jacquir, Sabir, E-mail: sjacquir@u-bourgogne.fr [LE2I, CNRS UMR 5158, Universite de Bourgogne, Dijon (France); Laurent, Gabriel; Bilbault, Jean-Marie [LE2I, CNRS UMR 5158, Universite de Bourgogne, Dijon (France); Binczak, Stephane, E-mail: stbinc@u-bourgogne.fr [LE2I, CNRS UMR 5158, Universite de Bourgogne, Dijon (France)

    2011-08-15

    Highlights: > Simulation of a cardiac tissue by a modified 2D FitzHugh-Nagumo model. > Stimulation of monophasic impulsions from a grid of electrodes to the cardiac tissue. > Propose a method by modifying the tissue's sodium channels and electrical stimulation. > The method leading to suppress spiral waves without generating new ones. > Optimal parameters of a successful suppression of spiral waves are investigated. - Abstract: Atrial fibrillation (AF) is the most common cardiac arrhythmia whose mechanisms are thought to be mainly due to the self perpetuation of spiral waves (SW). To date, available treatment strategies (antiarrhythmic drugs, radiofrequency ablation of the substrate, electrical cardioversion) to restore and to maintain a normal sinus rhythm have limitations and are associated with AF recurrences. The aim of this study was to assess a way of suppressing SW by applying multifocal electrical stimulations in a simulated cardiac tissue using a 2D FitzHugh-Nagumo model specially convenient for AF investigations. We identified stimulation parameters for successful termination of SW. However, SW reinduction, following the electrical stimuli, leads us to develop a hybrid strategy based on sodium channel modification for the simulated tissue.

  4. Lower hybrid wave resonance cone detection via CO/sub 2/ laser scattering

    Energy Technology Data Exchange (ETDEWEB)

    Wurden, G.A.; Wong, K.L.; Ono, M.

    1984-04-01

    Lower hybrid waves are studied in the Princeton ACT-I steady-state toroidal plasma device using a radially scanning CO/sub 2/ laser scattering system with both amplitude and phase sensitive detection techniques. Clearly defined resonance cones launched from external electrostatic antennas are seen to disappear as the plasma density is raised. Scaling of LHW laser signal with RF power in the presence of resonance cones shows nonlinearities associated with RF induced changes in the effective laser scattering volume. Absolute fluctuation level estimates suggest this occurs when e PHI/T/sub e/ greater than or equal to 1. Wavefront curvature effects can cause a complete loss of resonance cone laser signals, even though probes indicate that cones are still present. Measurements of the wave k/sub perpendicular/-spectrum in the plasma show direct evidence for electron Landau filtering of the original wave k/sub parallel/-spectrum launched from the antenna at the plasma edge, and strong dependence on antenna phasing. Finally, frequency shifts and loss of the resonance cone signal are associated with high levels of plasma density edge turbulence.

  5. Interaction between the lower hybrid wave and density fluctuations in the scrape-off layer

    Energy Technology Data Exchange (ETDEWEB)

    Peysson, Y., E-mail: yves.peysson@cea.fr [CEA, IRFM, 13108 Saint Paul-lez-Durance (France); Madi, M.; Kabalan, K. [AUB, Bliss Street (Lebanon); Decker, J. [EPFL, CRPP (Switzerland)

    2015-12-10

    In the present paper, the perturbation of the launched power spectrum of the Lower Hybrid wave at the separatrix by electron density fluctuations in the scrape-off layer is investigated. Considering a slab geometry with magnetic field lines parallel to the toroidal direction, the full wave equation is solved using Comsol Multiphysics® for a fully active multi-junction like LH antenna made of two modules. When electron density fluctuations are incorporated in the dielectric tensor over a thin perturbed layer in front of the grill, it is shown that the power spectrum may be strongly modified from the antenna mouth to the plasma separatrix as the wave propagates. The diffraction effect leads to the appearance of multiple satellite lobes with randomly varying positions, a feature consistent with the recently developed model that has been applied successfully to high density discharges on the Tokamak Tore Supra corresponding to the large spectral gap regime [Decker J. et al. Phys. Plasma 21 (2014) 092504]. The perturbation is found to be maximum for the Fourier components of the fluctuating spectrum in the vicinity of the launched LH wavelength.

  6. Plasma current start-up using the lower hybrid wave on the TST-2 spherical tokamak

    Science.gov (United States)

    Takase, Y.; Ejiri, A.; Inada, T.; Moeller, C. P.; Shinya, T.; Tsujii, N.; Yajima, S.; Furui, H.; Homma, H.; Imamura, K.; Nakamura, K.; Nakamura, K.; Sonehara, M.; Takeuchi, T.; Togashi, H.; Tsuda, S.; Yoshida, Y.

    2015-12-01

    Non-inductive plasma current start-up, ramp-up and sustainment by waves in the lower hybrid wave (LHW) frequency range at 200 MHz were investigated on the TST-2 spherical tokamak (R0 ≤ 0.38 m, a ≤ 0.25 m, Bt0 ≤ 0.3T, Ip ≤ 0.14 MA). Experimental results obtained using three types of antenna were compared. Both the highest plasma current (Ip = 18 kA) and the highest current drive figure of merit ηCD≡n¯eIpR0/PRF=1.4 ×1017 A/W/m2 were achieved using the capacitively-coupled combline (CCC) antenna, designed to excite the LHW with a sharp and highly directional wavenumber spectrum. For Ip greater than about 5 kA, high energy electrons accelerated by the LHW become the dominant carrier of plasma current. The low value of ηCD observed so far are believed to be caused by a rapid loss of energetic electrons and parasitic losses of the LHW energy in the plasma periphery. ηCD is expected to improve by an order of magnitude by increasing the plasma current to improve energetic electron confinement. In addition, edge power losses are expected to be reduced by increasing the toroidal magnetic field to improve wave accessibility to the plasma core, and by launching the LHW from the inboard upper region of the torus to achieve better single-pass absorption.

  7. Study on the Detectability of the Sky-Surface Wave Hybrid Radar

    Directory of Open Access Journals (Sweden)

    Hou Chengyu

    2014-01-01

    Full Text Available Working in the HF (high-frequency band and the transmitter and receiver locating separately, the sky-surface wave hybrid radar both has the capabilities of the OTHR (over-the-horizon radar and the advantage of the bistatic radar. As the electromagnetic wave will be disturbed by the ionosphere, interfered by the sea clutter and attenuated by the sea surface, the detectability of this radar system is more complex. So, in this paper, we will discuss the problem detailedly. First of all, the radar equation is deduced based on the propagation of the electromagnetic wave. Then, how to calculate the effect of the ionosphere and the propagation loss is discussed. And an example based on the radar equation is given. At last, the ambiguity function is used to analyze the range and velocity resolution. From the result, we find that the resolution has relation with the location of the target and the height of reflection point of the ionosphere. But compared with the location, the effect of the ionospheric height can be ignored.

  8. Study of Bridging of the Spectral Gap in the Lower Hybrid Wave Current Drive in the HT-7 Tokamak

    Institute of Scientific and Technical Information of China (English)

    WANG Mao; DING Bojiang; XU Handong; ZHAO Lianmin; LIU Liang; LIN Shiyao; XU Ping; SUN Youwen; HU Huaichuan; YANG Yong; JIA Hua; WANG Xiaojie; WANG Dongxia; QIN Yongliang; FENG Jianqiang; LIU Fukun; SHAN Jiafang; ZHAO Yanping; HT-7 team

    2009-01-01

    An additional lower hybrid wave (LHW) with a higher refractive index(N//)was investigated in the HT-7 tokamak to bridge the spectral gap.It was found that the spectral gap between the wave and the electrons in the outer region was bridged by the additional wave with a higher N// spectrum.The results showed that the sawteeth oscillation was suppressed by launching the additional wave,and that the power deposition profile was moved outwards and the current profile was broadened due to the application of the additional wave.Our study indicates that the spectral gap may be bridged by an additional wave with a higher N// spectrum in the outer region.

  9. Analysis of Upper Hybrid Wave Growth Rates From Measured Electron Distributions; An Encounter With the Source of Auroral Roar

    Science.gov (United States)

    Bounds, S. R.; Kletzing, C. A.; Labelle, J. W.; Samara, M.; Yoon, P. H.

    2005-12-01

    In January of 2003, the High Bandwidth Auroral Rocket (HIBAR) passed through two regions of strong upper hybrid wave emission associated with the approximate matching of the upper hybrid frequency to twice the electron cyclotron frequency (fuh = 2 fce) (Samara 2004) These types of emission are believed to be the source of the HF auroral roar often observed by ground based receivers. The current model theorizes that the free space 0-mode waves observed on the ground are produced through mode conversion of strong emission of Z-mode, or upper hybrid waves. The relativistic electron cyclotron maser exhibits significant growth rates for the Z-mode when the local upper hybrid frequency is just below (~1%) twice the electron cyclotron frequency and with the appropriately unstable electron distribution (Yoon 1996, Yoon 1998, Yoon 2000). Though auroral roar is frequently observed from the ground, the source region has rarely been identified in-situ and even more rarely with sufficient bandwidth to analyze the underlying physical processes. Analysis of the electron distributions from HIBAR show good agreement with the theoretical distributions used by Yoon:98. HIBAR encountered three separate regions where fuh ≍ 2 fce, two of these regions include strong upper hybrid emission, while the third is void of upper hybrid wave activity. The measured particle distributions demonstrate that, in the two regions with wave emission, the relativistic electron cyclotron maser instability produces Z mode wave growth rates at least an order of magnitude greater than the electron collision frequency. In the third region without wave emission, the growth rates are much smaller in both amplitude and the extent of occurance. Samara, M., J. LaBelle, C. A. Kletzing, and S. R. Bounds, Rocket observations of structured upper hybrid wave at fuh=2fce, Geophys. Res. Lett., 31, L22804, doi:10.1029/2004GL021043. Yoon, P. H., A. T. Weatherwax, and T. J. Rosenberg, Lower ionospheric cyclotron maser

  10. The Investigation of EM Scattering from the Time-Varying Overturning Wave Crest Model by the IEM

    Directory of Open Access Journals (Sweden)

    Xiao Meng

    2016-01-01

    Full Text Available Investigation of the electromagnetic (EM scattering of time-varying overturning wave crests is a worthwhile endeavor. Overturning wave crest is one of the reasons of sea spike generation, which increases the probability of false radar alarms and reduces the performance of multitarget detection in the environment. A three-dimensional (3D time-varying overturning wave crest model is presented in this paper; this 3D model is an improvement of the traditional two-dimensional (2D time-varying overturning wave crest model. The integral equation method (IEM was employed to investigate backward scattering radar cross sections (RCS at various incident angles of the 3D overturning wave crest model. The super phenomenon, where the intensity of horizontal polarization scattering is greater than that of vertical polarization scattering, is an important feature of sea spikes. Simulation results demonstrate that super phenomena may occur in some time samples as variations in the overturning wave crest.

  11. Hybrid simulations of whistler waves generation and current closure by a pulsed tether in the ionosphere

    Science.gov (United States)

    Chang, C. L.; Lipatov, A. S.; Drobot, A. T.; Papadopoulos, K.; Satya-Narayana, P.

    1994-01-01

    The dynamic response of a magnetized collisionless plasma to an externally driven, finite size, sudden switch-on current source across the magnetic field has been studied using a two dimensional hybrid code. It was found that the predominant plasma response was the excitation of whistler waves and the formation of current closure by induced currents in the plasma. The results show that the current closure path consists of: (a) two antiparallel field-aligned current channels at the end of the imposed current sheet; and (b) a cross-field current region connecting these channels. The formation of the current closure path occured in the whistler timescale much shorter than that of MHD and the closure region expanded continuously in time. The current closure process was accompanied by significant energy loss due to whistler radiation.

  12. Degenerate four wave mixing in large mode area hybrid photonic crystal fibers

    DEFF Research Database (Denmark)

    Petersen, Sidsel Rübner; Alkeskjold, Thomas Tanggaard; Lægsgaard, Jesper

    2013-01-01

    Spontaneous degenerate four wave mixing (FWM) is investigated in large mode area hybrid photonic crystal fibers, in which photonic bandgap guidance and index guidance is combined. Calculations show the parametric gain is maximum on the edge of a photonic bandgap, for a large range of pump...... wavelengths. The FWM products are observed on the edges of a transmission band experimentally, in good agreement with the numerical results. Thereby the bandedges can be used to control the spectral positions of FWM products through a proper fiber design. The parametric gain control combined with a large mode...... area fiber design potentially allows for power scaling of light at wavelengths not easily accessible with e.g. rare earth ions....

  13. Degenerate four wave mixing in large mode area hybrid photonic crystal fibers.

    Science.gov (United States)

    Petersen, Sidsel R; Alkeskjold, Thomas T; Lægsgaard, Jesper

    2013-07-29

    Spontaneous degenerate four wave mixing (FWM) is investigated in large mode area hybrid photonic crystal fibers, in which photonic bandgap guidance and index guidance is combined. Calculations show the parametric gain is maximum on the edge of a photonic bandgap, for a large range of pump wavelengths. The FWM products are observed on the edges of a transmission band experimentally, in good agreement with the numerical results. Thereby the bandedges can be used to control the spectral positions of FWM products through a proper fiber design. The parametric gain control combined with a large mode area fiber design potentially allows for power scaling of light at wavelengths not easily accessible with e.g. rare earth ions.

  14. A Novel Cell-Based Hybrid Acoustic Wave Biosensor with Impedimetric Sensing Capabilities

    Directory of Open Access Journals (Sweden)

    Ioana Voiculescu

    2013-03-01

    Full Text Available A novel multiparametric biosensor system based on living cells will be presented. The biosensor system includes two biosensing techniques on a single device: resonant frequency measurements and electric cell-substrate impedance sensing (ECIS. The multiparametric sensor system is based on the innovative use of the upper electrode of a quartz crystal microbalance (QCM resonator as working electrode for the ECIS technique. The QCM acoustic wave sensor consists of a thin AT-cut quartz substrate with two gold electrodes on opposite sides. For integration of the QCM with the ECIS technique a semicircular counter electrode was fabricated near the upper electrode on the same side of the quartz crystal. Bovine aortic endothelial live cells (BAECs were successfully cultured on this hybrid biosensor. Finite element modeling of the bulk acoustic wave resonator using COMSOL simulations was performed. Simultaneous gravimetric and impedimetric measurements performed over a period of time on the same cell culture were conducted to validate the device’s sensitivity. The time necessary for the BAEC cells to attach and form a compact monolayer on the biosensor was 35~45 minutes for 1.5 × 104 cells/cm2 BAECs; 60 minutes for 2.0 × 104 cells/cm2 BAECs; 70 minutes for 3.0 × 104 cells/cm2 BAECs; and 100 minutes for 5.0 × 104 cells/cm2 BAECs. It was demonstrated that this time is the same for both gravimetric and impedimetric measurements. This hybrid biosensor will be employed in the future for water toxicity detection.

  15. Non-conforming hybrid meshes for efficient 2-D wave propagation using the Discontinuous Galerkin Method

    Science.gov (United States)

    Hermann, Verena; Käser, Martin; Castro, Cristóbal E.

    2011-02-01

    We present a Discontinuous Galerkin finite element method using a high-order time integration technique for seismic wave propagation modelling on non-conforming hybrid meshes in two space dimensions. The scheme can be formulated to achieve the same approximation order in space and time and avoids numerical artefacts due to non-conforming mesh transitions or the change of the element type. A point-wise Gaussian integration along partially overlapping edges of adjacent elements is used to preserve the schemes accuracy while providing a higher flexibility in the problem-adapted mesh generation process. We describe the domain decomposition strategy of the parallel implementation and validate the performance of the new scheme by numerical convergence test and experiments with comparisons to independent reference solutions. The advantage of non-conforming hybrid meshes is the possibility to choose the mesh spacing proportional to the seismic velocity structure, which allows for simple refinement or coarsening methods even for regular quadrilateral meshes. For particular problems of strong material contrasts and geometrically thin structures, the scheme reduces the computational cost in the sense of memory and run-time requirements. The presented results promise to achieve a similar behaviour for an extension to three space dimensions where the coupling of tetrahedral and hexahedral elements necessitates non-conforming mesh transitions to avoid linking elements in form of pyramids.

  16. The dynamic dielectric at a brain functional site and an EM wave approach to functional brain imaging.

    Science.gov (United States)

    Li, X P; Xia, Q; Qu, D; Wu, T C; Yang, D G; Hao, W D; Jiang, X; Li, X M

    2014-11-04

    Functional brain imaging has tremendous applications. The existing methods for functional brain imaging include functional Magnetic Resonant Imaging (fMRI), scalp electroencephalography (EEG), implanted EEG, magnetoencephalography (MEG) and Positron Emission Tomography (PET), which have been widely and successfully applied to various brain imaging studies. To develop a new method for functional brain imaging, here we show that the dielectric at a brain functional site has a dynamic nature, varying with local neuronal activation as the permittivity of the dielectric varies with the ion concentration of the extracellular fluid surrounding neurons in activation. Therefore, the neuronal activation can be sensed by a radiofrequency (RF) electromagnetic (EM) wave propagating through the site as the phase change of the EM wave varies with the permittivity. Such a dynamic nature of the dielectric at a brain functional site provides the basis for an RF EM wave approach to detecting and imaging neuronal activation at brain functional sites, leading to an RF EM wave approach to functional brain imaging.

  17. An adaptive metamaterial beam with hybrid shunting circuits for extremely broadband control of flexural wave (Conference Presentation)

    Science.gov (United States)

    Chen, Yangyang; Huang, Guoliang

    2017-04-01

    A great deal of research has been devoted to controlling the dynamic behaviors of phononic crystals and metamaterials by directly tuning the frequency regions and/or widths of their inherent band gaps. Here, we present a novel approach to achieve extremely broadband flexural wave/vibration attenuation based on tunable local resonators made of piezoelectric stacks shunted by hybrid negative capacitance and negative inductance circuits with proof masses attached on a host beam. First, wave dispersion relations of the adaptive metamaterial beam are calculated analytically by using the transfer matrix method. The unique modulus tuning properties induced by the hybrid shunting circuits are then characterized conceptually, from which the frequency dependent modulus tuning curves of the piezoelectric stack located within wave attenuation frequency regions are quantitatively identified. As an example, a flexural wave high-pass band filter with a wave attenuation region from 0 to 23.0 kHz is demonstrated analytically and numerically by using the hybrid shunting circuit, in which the two electric components are connected in series. By changing the connection pattern to be parallel, another super wide wave attenuation region from 13.5 to 73.0 kHz is demonstrated to function as a low-pass filter at a subwavelength scale. The proposed adaptive metamaterial possesses a super wide band gap created both naturally and artificially. Therefore, it can be used for the transient wave mitigation at extremely broadband frequencies such as blast or impact loadings. We envision that the proposed design and approach can open many possibilities in broadband vibration and wave control.

  18. Density convection near radiating ICRF antennas and its effect on the coupling of lower hybrid waves

    Energy Technology Data Exchange (ETDEWEB)

    Ekedahl, A.; Colas, L.; Beaumont, B.; Bibet, Ph.; Bremond, S.; Kazarian, F. [Association Euratom-CEA Cadarache, 13 - Saint-Paul-lez-Durance (France). Dept. de Recherches sur la Fusion Controlee; Mayoral, M.L.; Mailloux, J. [Euratom/UKAEA Fusion Association, Culham Science Centre, Abingdon, OX (United Kingdom); Noterdaeme, J.M. [Max-Planck-Institut fuer Plasmaphysik, Euratom Association, Garching (Germany)]|[Gent University, EESA Dept. (Belgium); Tuccillo, A.A. [Associazione Euratom-ENEA sulla Fusione, CR Frascati, Rome (Italy)

    2003-07-01

    Combined operation of lower hybrid (LH) and Ion Cyclotron Resonance Frequency (ICRF) waves can result in a degradation of the LH wave coupling, as observed both in the Tore-Supra and Jet tokamaks. The reflection coefficient on the part of the LH launcher magnetically connected to the powered ICRF antenna increases, suggesting a local decrease in the electron density in the connecting flux tubes. This has been confirmed by Langmuir probe measurements on the LH launchers in the latest Tore-Supra experiments. Moreover, recent experiments in Jet indicate that the LH coupling degradation depends on the ICRF power and its launched k{sub /} spectrum. The 2D density distribution around the Tore-Supra ICRF antennas has been modelled with the CELLS-code, balancing parallel losses with diffusive transport and sheath induced ExB convection, obtained from RF field mapping using the ICANT-code. The calculations are in qualitative agreement with the experimental observations, i.e. density depletion is obtained, localised mainly in the antenna shadow, and dependent on ICRF power and antenna spectrum. (authors)

  19. Modification of ordinary-mode reflectometry system to detect lower-hybrid waves in Alcator C-Moda)

    Science.gov (United States)

    Baek, S. G.; Shiraiwa, S.; Parker, R. R.; Dominguez, A.; Kramer, G. J.; Marmar, E. S.

    2012-10-01

    Backscattering experiments to detect lower-hybrid (LH) waves have been performed in Alcator C-Mod, using the two modified channels (60 GHz and 75 GHz) of an ordinary-mode reflectometry system with newly developed spectral recorders that can continuously monitor spectral power at a target frequency. The change in the baseline of the spectral recorder during the LH wave injection is highly correlated to the strength of the X-mode non-thermal electron cyclotron emission. In high density plasmas where an anomalous drop in the lower hybrid current drive efficiency is observed, the observed backscattered signals are expected to be generated near the last closed flux surface, demonstrating the presence of LH waves within the plasma. This experimental technique can be useful in identifying spatially localized LH electric fields in the periphery of high-density plasmas.

  20. Hybrid local FEM/global LISA modeling of guided wave propagation and interaction with damage in composite structures

    Science.gov (United States)

    Shen, Yanfeng; Cesnik, Carlos E. S.

    2015-03-01

    This paper presents a hybrid modeling technique for the efficient simulation of guided wave propagation and interaction with damage in composite structures. This hybrid approach uses a local finite element model (FEM) to compute the excitability of guided waves generated by piezoelectric transducers, while the global domain wave propagation, wave-damage interaction, and boundary reflections are modeled with the local interaction simulation approach (LISA). A small-size multi-physics FEM with non-reflective boundaries (NRB) was built to obtain the excitability information of guided waves generated by the transmitter. Frequency-domain harmonic analysis was carried out to obtain the solution for all the frequencies of interest. Fourier and inverse Fourier transform and frequency domain convolution techniques are used to obtain the time domain 3-D displacement field underneath the transmitter under an arbitrary excitation. This 3-D displacement field is then fed into the highly efficient time domain LISA simulation module to compute guided wave propagation, interaction with damage, and reflections at structural boundaries. The damping effect of composite materials was considered in the modified LISA formulation. The grids for complex structures were generated using commercial FEM preprocessors and converted to LISA connectivity format. Parallelization of the global LISA solution was achieved through Compute Unified Design Architecture (CUDA) running on Graphical Processing Unit (GPU). The multi-physics local FEM can reliably capture the detailed dimensions and local dynamics of the piezoelectric transducers. The global domain LISA can accurately solve the 3-D elastodynamic wave equations in a highly efficient manner. By combining the local FEM with global LISA, the efficient and accurate simulation of guided wave structural health monitoring procedure is achieved. Two numerical case studies are presented: (1) wave propagation in a unidirectional CFRP composite plate

  1. Semi-classical description of matter wave interferometers and hybrid quantum systems

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, Mathias

    2015-02-16

    This work considers the semi-classical description of two applications involving cold atoms. This is, on one hand, the behavior of a BOSE-EINSTEIN condensate in hybrid systems, i.e. in contact with a microscopic object (carbon nanotubes, fullerenes, etc.). On the other, the evolution of phase space distributions in matter wave interferometers utilizing ray tracing methods was discussed. For describing condensates in hybrid systems, one can map the GROSS-PITAEVSKII equation, a differential equation in the complex-valued macroscopic wave function, onto a system of two differential equations in density and phase. Neglecting quantum dispersion, one obtains a semiclassical description which is easily modified to incorporate interactions between condensate and microscopical object. In our model, these interactions comprise attractive forces (CASIMIR-POLDER forces) and loss of condensed atoms due to inelastic collisions at the surface of the object. Our model exhibited the excitation of sound waves that are triggered by the object's rapid immersion, and spread across the condensate thereafter. Moreover, local particle loss leads to a shrinking of the bulk condensate. We showed that the total number of condensed particles is decreasing potentially in the beginning (large condensate, strong mean field interaction), while it decays exponentially in the long-time limit (small condensate, mean field inetraction negligible). For representing the physics of matter wave interferometers in phase space, we utilized the WIGNER function. In semi-classical approximation, which again consists in ignoring the quantum dispersion, this representation is subject to the same equation of motion as classical phase space distributions, i.e. the LIOUVILLE equation. This implies that time evolution of theWIGNER function follows a phase space flow that consists of classical trajectories (classical transport). This means, for calculating a time-evolved distribution, one has know the initial

  2. The hybrid of SnO2 nanoparticle and polypyrrole aerogel: an excellent electromagnetic wave absorbing materials

    Science.gov (United States)

    Wang, Yu; Dai, Xiaoqing; Jiang, Wanchun; Wu, Fan; Xie, Aming

    2016-07-01

    As a kind of costless and lightweight material, SnO2 nanoparticles@polypyrrole hybrid aerogels have been synthesized and displayed electromagnetic wave absorbing (EWA) performance. Only with 10 wt% of nano-SnO2 filler loading in wax, effective EWA bandwidth of the hybrid aerogel can reach 7.28 GHz which is the widest lightweight EWA material among the reported absorbents. Through the regulation of sample thicknesses, effective EWA at lower frequencies can also be achieved. It was demonstrated that this aerogel can be used as an effective lightweight broadband EWA material.

  3. Multi-spacecraft observations of broadband waves near the lower hybrid frequency at the Earthward edge of the magnetopause

    Directory of Open Access Journals (Sweden)

    M. André

    Full Text Available Broadband waves around the lower hybrid frequency (around 10 Hz near the magnetopause are studied, using the four Cluster satellites. These waves are common at the Earthward edge of the boundary layer, consistent with earlier observations, and can have amplitudes at least up to 5 mV/m. These waves are similar on all four Cluster satellites, i.e. they are likely to be distributed over large areas of the boundary. The strongest electric fields occur during a few seconds, i.e. over distances of a few hundred km in the frame of the moving magnetopause, a scale length comparable to the ion gyroradius. The strongest magnetic oscillations in the same frequency range are typically found in the boundary layer, and across the magnetopause. During an event studied in detail, the magnetopause velocity is consistent with a large-scale depression wave, i.e. an inward bulge of magnetosheath plasma, moving tailward along the nominal magnetopause boundary. Preliminary investigations indicate that a rather flat front side of the large-scale wave is associated with a rather static small-scale electric field, while a more turbulent backside of the large-scale wave is associated with small-scale time varying electric field wave packets.

    Key words. Magnetospheric physics (magnetopause, cusp, and boundary layers – Space plasma physics (waves and in-stabilities

  4. Experimental characterization of the lower hybrid wave field on the first pass using a magnetic probe array

    Science.gov (United States)

    Shinya, T.; Baek, S. G.; Wallace, G. M.; Parker, R. R.; Shiraiwa, S.; Takase, Y.

    2016-10-01

    Experimental characterization of the lower hybrid (LH) wave propagation from the launcher to the core plasma is important to validate an antenna spectrum model and to identify parasitic wave-edge plasma interactions occurring in front of the launcher. On Alcator C-Mod, the wave frequency spectrum and dominant parallel wavenumber are characterized with two probe arrays installed near the edge plasma. The first one is mounted on a radially movable structure that is about 108 deg toroidally away from the launcher. A phasing scan experiment at moderate density suggests a resonance-cone propagation of the launched slow LH wave with a finite spectral width. As plasma density is raised, the measured power decreases, correlated with the observed loss of efficiency. Recently, the second probe array with an increased number of probes has been installed on a limiter that is 54 deg. toroidally away from the launcher, which is expected to be dominantly sensitive to the wave-field directly leaving the launcher. An initial measurement shows that the probe array detects a coherent wave field. A full-wave model to evaluate the wave electric-field pattern in front of the probe array is under development. If available, further experimental and modeling results will be presented. Supported by USDoE Award(s) DE-FC02-99ER54512 and Japan/U.S. Cooperation in Fusion Research and Development.

  5. Observations of a free-energy source for intense electrostatic waves. [in upper atmosphere near upper hybrid resonance frequency

    Science.gov (United States)

    Kurth, W. S.; Frank, L. A.; Gurnett, D. A.; Burek, B. G.; Ashour-Abdalla, M.

    1980-01-01

    Significant progress has been made in understanding intense electrostatic waves near the upper hybrid resonance frequency in terms of the theory of multiharmonic cyclotron emission using a classical loss-cone distribution function as a model. Recent observations by Hawkeye 1 and GEOS 1 have verified the existence of loss-cone distributions in association with the intense electrostatic wave events, however, other observations by Hawkeye and ISEE have indicated that loss cones are not always observable during the wave events, and in fact other forms of free energy may also be responsible for the instability. Now, for the first time, a positively sloped feature in the perpendicular distribution function has been uniquely identified with intense electrostatic wave activity. Correspondingly, we suggest that the theory is flexible under substantial modifications of the model distribution function.

  6. A Comment on Interaction of Lower Hybrid Waves with the Current-Driven Ion-Acoustic Instability

    DEFF Research Database (Denmark)

    Schrittwieser, R.; Juul Rasmussen, Jens

    1985-01-01

    Majeski et al. (1984) have investigated the interaction between the current-driven 'ion-acoustic' instability and high frequency lower hybrid waves. The 'ion-acoustic' instability was excited by drawing an electron current through the plasma column of a single-ended Q-machine by means of a positi......Majeski et al. (1984) have investigated the interaction between the current-driven 'ion-acoustic' instability and high frequency lower hybrid waves. The 'ion-acoustic' instability was excited by drawing an electron current through the plasma column of a single-ended Q-machine by means...... of a positively biased cold plate. Schmittwieser et al. do not believe that the observed instability is of the ion-acoustic type but that it is rather the so-called potential relaxation instability....

  7. Enabling inter- and intra-chip optical wireless interconnect by the aid of hybrid plasmonic leaky-wave optical antennas

    Science.gov (United States)

    Ebrahimi, Vahid; Yousefi, Leila; Mohammad-Taheri, Mahmoud

    2017-01-01

    In this paper, we propose a new method to provide optical link in Photonic Integrated Circuits (PICs). The proposed method uses two hybrid plasmonic leaky-wave optical antennas, operating at the standard optical telecommunication wavelength of 1.55 μm, to provide inter-chip interconnect between two layers in a photonic chip and also intra-chip interconnect between two different photonic ICs. Linearly tapered couplers are designed to couple the optical signal from the silicon waveguide to the hybrid plasmonic antennas. The performance of the proposed optical link is verified using numerical full wave simulation. The proposed structure is planar, and can be fabricated using standard CMOS technology which makes it the superior candidate for realization of future multi-layered Photonic Integrated Circuits.

  8. Design and implementation of a multichannel millimeter wave interferometer for the Compact Toroidal Hybrid experiment

    Energy Technology Data Exchange (ETDEWEB)

    Miller, M. C.; Hanson, J. D.; Hartwell, G. J.; Knowlton, S. F.; Maurer, D. A.; Stevenson, B. A. [Physics Department, Auburn University, Auburn, Alabama 36849 (United States)

    2012-10-15

    A three-channel 1 mm wave interferometer has been designed, assembled, and installed on the Compact Toroidal Hybrid torsatron (CTH). The interferometer design makes novel use of a subharmonic mixer for detection, which simplifies alignment. It employs a single electronically tunable source that is repetitively chirped using a sawtooth waveform of frequency up to 1 MHz. The 15.25 GHz drive oscillator is multiplied in two stages to 122 GHz before a final doubler stage brings it to 244 GHz. Local oscillator (LO) power at 122 GHz is directed through waveguide to the LO input of the subharmonic mixer of each viewing chord, simplifying alignment. Phase detection is performed by directly digitizing the amplified mixer outputs at 50 MHz and processing them with a software algorithm. Initial measurements made with the central chord of the new interferometer agree with those from the existing 4 mm system at low densities. The 1 mm system performs well in current-driven discharges reaching densities over 10{sup 19} m{sup -3}, whereas the lower frequency interferometer is found to be less reliable due to loss of fringes. This is a critical improvement for experiments studying the onset, avoidance, and vacuum magnetic transform dependence of disruptions in the CTH device.

  9. Antenna-coupled silicon-organic hybrid integrated photonic crystal modulator for broadband electromagnetic wave detection

    CERN Document Server

    Zhang, Xingyu; Subbaraman, Harish; Wang, Shiyi; Zhan, Qiwen; Luo, Jingdong; Jen, Alex K -Y; Chung, Chi-jui; Yan, Hai; Pan, Zeyu; Nelson, Robert L; Lee, Charles Y -C; Chen, Ray T

    2015-01-01

    In this work, we design, fabricate and characterize a compact, broadband and highly sensitive integrated photonic electromagnetic field sensor based on a silicon-organic hybrid modulator driven by a bowtie antenna. The large electro-optic (EO) coefficient of organic polymer, the slow-light effects in the silicon slot photonic crystal waveguide (PCW), and the broadband field enhancement provided by the bowtie antenna, are all combined to enhance the interaction of microwaves and optical waves, enabling a high EO modulation efficiency and thus a high sensitivity. The modulator is experimentally demonstrated with a record-high effective in-device EO modulation efficiency of r33=1230pm/V. Modulation response up to 40GHz is measured, with a 3-dB bandwidth of 11GHz. The slot PCW has an interaction length of 300um, and the bowtie antenna has an area smaller than 1cm2. The bowtie antenna in the device is experimentally demonstrated to have a broadband characteristics with a central resonance frequency of 10GHz, as we...

  10. Global SH-wave propagation in a 2D whole Moon model using the parallel hybrid PSM/FDM method

    Science.gov (United States)

    Jiang, Xianghua; Wang, Yanbin; Qin, Yanfang; Takenaka, Hiroshi

    2015-06-01

    We present numerical modeling of SH-wave propagation for the recently proposed whole Moon model and try to improve our understanding of lunar seismic wave propagation. We use a hybrid PSM/FDM method on staggered grids to solve the wave equations and implement the calculation on a parallel PC cluster to improve the computing efficiency. Features of global SH-wave propagation are firstly discussed for a 100-km shallow and 900-km deep moonquakes, respectively. Effects of frequency range and lateral variation of crust thickness are then investigated with various models. Our synthetic waveforms are finally compared with observed Apollo data to show the features of wave propagation that were produced by our model and those not reproduced by our models. Our numerical modeling show that the low-velocity upper crust plays significant role in the development of reverberating wave trains. Increasing frequency enhances the strength and duration of the reverberations. Surface multiples dominate wavefields for shallow event. Core-mantle reflections can be clearly identified for deep event at low frequency. The layered whole Moon model and the low-velocity upper crust produce the reverberating wave trains following each phases consistent with observation. However, more realistic Moon model should be considered in order to explain the strong and slow decay scattering between various phases shown on observation data.

  11. A hyperbolic function approach to constructing exact solitary wave solutions of the Hybrid lattice and discrete mKdV lattice

    Institute of Scientific and Technical Information of China (English)

    Zha Qi-Lao; Sirendaoreji

    2006-01-01

    Some new exact solitary wave solutions of the Hybrid lattice and discrete mKdV lattice are obtained by using a hyperbolic function approach.This approach can also be applied to other nonlinear differential-difference equations.

  12. ‘Who Said It Was Simple!’ Third-Wave Feminist Coalition and Audre Lorde's Intersectionalist Hybrid Poetics of Difference

    Directory of Open Access Journals (Sweden)

    Yomna Saber

    2015-05-01

    Full Text Available Third-Wave Feminism digs its roots in intersectionality and coalition, which were not fully realised in Second-Wave Feminism. However, the movement is usually under attack for lacking a clear agenda. Recent scholarship strongly suggests that third wavers get back to third-world writers, like Audre Lorde, to realise an anti-racist and inclusive feminism.  Lorde occupies a distinctive position in feminist literature; a poet who resides in too many margins being black, female and lesbian. This essay draws an analogy between third wave intersectionality and postcolonial hybridity, and argues that Lorde's use of hybridity is a 'third space' that she opens up in her poetry to disrupt spheres of supremacy through its interdependence and reciprocal construction that defy dualisms, hence realising coalition. The analysis is anchored by HomiBhabha's definition of hybridity in colonial discourse. Key Words: Third-Wave Feminism, intersectionality, hybridity, dualism, Audre Lorde, HomiBhabha.

  13. Design and Analysis of the AlNiCo Hybrid Magnet in EMS Maglev Vehicles

    Directory of Open Access Journals (Sweden)

    Lv Chao

    2017-01-01

    Full Text Available In order to solve the problem of hybrid electromagnet lock orbit, we design a new type of AlNiCo-NdFeB hybrid levitation electromagnet. The theoretical analysis has be carried on and mathematical model is established for AlNiCo-NdFeB hybrid levitation electromagnet. Through two dimensional simulation, the electromagnetic characteristics of the suspended electromagnet are analyzed in the 3 typical operating conditions , which are in heavy load at gap 8mm, in full load at gap 16mm and in no-load at gap 3mm. And it’s compared with the traditional electromagnetic magnet and NdFeB hybrid electromagnet. Calculation and analysis show that the new hybrid levitation electromagnet can effectively solve the problems of the electromagnet lock orbit, at the same time, have a good dynamic performance and suspension regulation performance.

  14. Is Hybrid Education and Videoconferencing the Wave of the Future for Online Courses?

    Science.gov (United States)

    Popma, Joe

    2012-01-01

    A comprehensive literature review examines the effectiveness of hybrid education utilizing videoconferencing. The observations and perceptions of both students and the instructor participating in a hybrid pilot program will be discussed. Discussion highlights the value of hybrid education within the context of the students' busy schedules and…

  15. Catastrophic instabilities of modified DA-DC hybrid surface waves in a semi-bounded plasma system

    Science.gov (United States)

    Lee, Myoung-Jae; Jung, Young-Dae

    2016-06-01

    We find the catastrophic instabilities and derive the growth rates for the dust-cyclotron resonance (DCR) and dust-rotation resonance (DRR) modes of the modified dust-acoustic and dust-cyclotron (DA-DC) hybrid surface waves propagating at the plasma-vacuum interface where the plasma is semi-bounded and composed of electrons and rotating dust grains. The effects of magnetic field and dust rotation frequency on the DCR- and DDR-modes are also investigated. We find that the dust rotation frequency enhances the growth rate of DCR-mode and the effect of dust rotation on this resonance mode decreases with an increase of the wave number. We also find that an increase of magnetic field strength enhances the DCR growth rate, especially, for the short wavelength regime. In the case of DRR-mode, the growth rate is found to be decreased less sensitively with an increase of the wave number compared with the case of DCR, but much significantly enhanced by an increase of dust rotation frequency. The DRR growth rate also decreases with an increase of the magnetic field strength, especially in the long wavelength regime. Interestingly, we find that catastrophic instabilities occur for both DCR- and DRR-modes of the modified DA-DC hybrid surface waves when the rotational frequency is close to the dust-cyclotron frequency. Both modes can also be excited catastrophically due to the cooperative interaction between the DCR-mode and the DRR-mode.

  16. A hybrid MAC protocol design for energy-efficient very-high-throughput millimeter wave, wireless sensor communication networks

    Science.gov (United States)

    Jian, Wei; Estevez, Claudio; Chowdhury, Arshad; Jia, Zhensheng; Wang, Jianxin; Yu, Jianguo; Chang, Gee-Kung

    2010-12-01

    This paper presents an energy-efficient Medium Access Control (MAC) protocol for very-high-throughput millimeter-wave (mm-wave) wireless sensor communication networks (VHT-MSCNs) based on hybrid multiple access techniques of frequency division multiplexing access (FDMA) and time division multiplexing access (TDMA). An energy-efficient Superframe for wireless sensor communication network employing directional mm-wave wireless access technologies is proposed for systems that require very high throughput, such as high definition video signals, for sensing, processing, transmitting, and actuating functions. Energy consumption modeling for each network element and comparisons among various multi-access technologies in term of power and MAC layer operations are investigated for evaluating the energy-efficient improvement of proposed MAC protocol.

  17. Global effects of transmitted shock wave propagation through the Earth's inner magnetosphere: First results from 3-D hybrid kinetic modeling

    Science.gov (United States)

    Lipatov, A. S.; Sibeck, D. G.

    2016-09-01

    We use a new hybrid kinetic model to simulate the response of ring current, outer radiation belt, and plasmaspheric particle populations to impulsive interplanetary shocks. Since particle distributions attending the interplanetary shock waves and in the ring current and radiation belts are non-Maxwellian, wave-particle interactions play a crucial role in energy transport within the inner magnetosphere. Finite gyroradius effects become important in mass loading the shock waves with the background plasma in the presence of higher energy ring current and radiation belt ions and electrons. Initial results show that shocks cause strong deformations in the global structure of the ring current, radiation belt, and plasmasphere. The ion velocity distribution functions at the shock front, in the ring current, and in the radiation belt help us determine energy transport through the Earth's inner magnetosphere.

  18. A hybrid surface layer parameterization scheme for the two-way fully coupled atmosphere-ocean wave system WEW

    Science.gov (United States)

    Katsafados, Petros; Papadopoulos, Anastasios; Varlas, George; Korres, Gerasimos

    2015-04-01

    The two-way fully coupled atmosphere-ocean wave system WEW has been recently developed in order to study the factors that contribute to the air-sea interaction processes and feedbacks. The coupled system consists of two components: the atmospheric component which is based on the Workstation Eta non-hydrostatic limited area model and the ocean-wave component which is based on the fourth generation OpenMP (OMP) version of the WAM model. The WEW has been already evaluated in a number of high-impact weather and sea state events where generally a more realistic representation of the momentum exchanges in the ocean wind-wave system has been shown However, the new developed wind-wave parameterization scheme reduces both the near surface wind speed and the significant wave height as a response to the increased aerodynamic drag considered by the atmospheric model over rough sea surfaces. Such behavior is mainly attributed to the surface layer parameterization scheme of the atmospheric component which is based on the Mellor-Yamada-Janjic (MYJ) scheme. It is noted that this scheme has been adjusted to support independent atmospheric simulations. Therefore, we proceed to develop a new hybrid surface layer parameterization based on the MYJ and the Janssen schemes that operate in the atmospheric and ocean wave components of the WEW, respectively. In this case the roughness length depends on the wave age instead of the Charnock parameter following the formulation proposed by Vickers and Mahrt. The spatial variability of the wave age is estimated at each ocean wave component time step and it is directly provided to the MYJ scheme. The parameterization of the viscous sublayer and the universal functions for the estimation of the near surface wind speed have been also revised accordingly. In this study, a test version of the new hybrid scheme of WEW has been statistically evaluated against a number of buoys and satellite retrievals over the Mediterranean Sea in a case study of high

  19. Inhibition of Salmonella typhi growth using extremely low frequency electromagnetic (ELF-EM) waves at resonance frequency.

    Science.gov (United States)

    Fadel, M A; Mohamed, S A; Abdelbacki, A M; El-Sharkawy, A H

    2014-08-01

    Typhoid is a serious disease difficult to be treated with conventional drugs. The aim of this study was to demonstrate a new method for the control of Salmonella typhi growth, through the interference with the bioelectric signals generated from the microbe during cell division by extremely low frequency electromagnetic waves (ELF-EMW-ELF-EM) at resonance frequency. Isolated Salmonella typhi was subjected to square amplitude modulated waves (QAMW) with different modulation frequencies from two generators with constant carrier frequency of 10 MHz, amplitude of 10 Vpp, modulating depth ± 2 Vpp and constant field strength of 200 V m(-1) at 37°C. Both the control and exposed samples were incubated at the same conditions during the experiment. The results showed that there was highly significant inhibition effect for Salm. typhi exposed to 0·8 Hz QAMW for a single exposure for 75 min. Dielectric relaxation, TEM and DNA results indicated highly significant changes in the molecular structure of the DNA and cellular membrane resulting from the exposure to the inhibiting EM waves. It was concluded that finding out the inhibiting resonance frequency of ELF-EM waves that deteriorates Salm. typhi growth will be promising method for the treatment of Salm. typhi infection either in vivo or in vitro. This new non-invasive technique for treatment of bacterial infections is of considerable interest for the use in medical and biotechnological applications. © 2014 The Society for Applied Microbiology.

  20. Ecocardiografia modo Doppler pulsado em gatos clinicamente sadios Pulsed wave Doppler echocardiography in clinically healthy cats

    Directory of Open Access Journals (Sweden)

    R.O. Carvalho

    2006-06-01

    Full Text Available Estudou-se o fluxo sangüíneo através das quatro valvas cardíacas em 30 gatos clinicamente sadios, com idade entre um e cinco anos e peso médio de 4,08kg, por meio da ecocardiografia modo Doppler pulsado. Foram medidas a velocidade máxima e a velocidade média dos fluxos, e realizou-se uma análise qualitativa dos seus perfis. Os animais foram sedados pela combinação de quetamina (12mg/kg e acepromazina (0,04mg/kg, aplicados por via intramuscular. Observou-se correlação positiva entre os parâmetros avaliados e a freqüência cardíaca, com exceção daqueles medidos no fluxo da valva aórtica. Não se observou correlação entre velocidades máxima e média e freqüência cardíaca e entre aquelas e peso corporal, e não houve diferença entre sexos.Pulsed wave Doppler echocardiography was used to study blood flow across the cardiac valves in 30 five-year-old cats (average body weight = 4.08kg. Animals were sedated using a combination of ketamin (12mg/kg, IM and acepromazin (0.04mg/kg, IM. Peak and mean velocities were determined, and blood flow patterns were recorded at the four cardiac valves. All variables, except those characterizing aortic valve flow, were positively correlated with heart rate. Blood flow variables were not correlated, however, with body weight; and there were no differences between males and females.

  1. Conversion of electrostatic upper hybrid emissions to electromagnetic O and X mode waves in the Earth's magnetosphere

    Energy Technology Data Exchange (ETDEWEB)

    Budden, K.G.; Jones, D.

    1987-02-01

    The linear conversion of electrostatic upper hybrid emissions via the Z mode to electromagnetic ordinary (O) mode waves has for some time been invoked for the source of Terrestrial and Saturnian myriametric and Jovian kilometric radiations. The conversion occurs by virtue of the emissions' propagation in concentration gradients, and for it to be efficient it is necessary for the gradient to be normal to the ambient magnetic field. Suitable concentration gradients are believed to occur at the plasmapause and at the magnetopause. Ray theory predicts only O mode production whereas full wave theory in a cold plasma shows that both O and X (extraordinary) mode are produced, their relative intensities depending on the plasma parameters. Full wave theory in a warm plasma, besides yielding more accurate information on the O and X modes also provides an insight into the effect of conversion on the source plasma wave. Results obtained from these three levels of theory are compared using plasma parameters derived from wave experiments on spacecraft.

  2. Proton Heating by Pick-up Ion Driven Cyclotron Waves in the Outer Heliosphere: Hybrid Expanding Box Simulations

    Science.gov (United States)

    Hellinger, Petr; Trávníček, Pavel M.

    2016-11-01

    Using a one-dimensional hybrid expanding box model, we investigate properties of the solar wind in the outer heliosphere. We assume a proton-electron plasma with a strictly transverse ambient magnetic field and, aside from the expansion, we take into account the influence of a continuous injection of cold pick-up protons through the charge-exchange process between the solar wind protons and hydrogen of interstellar origin. The injected cold pick-up protons form a ring distribution function, which rapidly becomes unstable, and generate Alfvén cyclotron waves. The Alfvén cyclotron waves scatter pick-up protons to a spherical shell distribution function that thickens over that time owing to the expansion-driven cooling. The Alfvén cyclotron waves heat solar wind protons in the perpendicular direction (with respect to the ambient magnetic field) through cyclotron resonance. At later times, the Alfvén cyclotron waves become parametrically unstable and the generated ion-acoustic waves heat protons in the parallel direction through Landau resonance. The resulting heating of the solar wind protons is efficient on the expansion timescale.

  3. Proton heating by pick-up ion driven cyclotron waves in the outer heliosphere: Hybrid expanding box simulations

    CERN Document Server

    Hellinger, Petr

    2016-01-01

    Using one-dimensional hybrid expanding box model we investigate properties of the solar wind in the outer heliosphere. We assume a proton-electron plasma with a strictly transverse ambient magnetic field and, beside the expansion, we take into account influence of a continuous injection of cold pick-up protons through the charge-exchange process between the solar wind protons and hydrogen of interstellar origin. The injected cold pick-up protons form a ring distribution function that rapidly becomes unstable and generate Alfv\\'en cyclotron waves. The Alfv\\'en cyclotron waves scatter pick-up protons to a spherical shell distribution function that thickens over that time owing to the expansion-driven cooling. The Alf\\'ven cyclotron waves heat solar wind protons in the perpendicular direction (with respect to the ambient magnetic field) through the cyclotron resonance. At later times, the Alfv\\'en cyclotron waves become parametrically unstable and the generated ion acoustic waves heat protons in the parallel dir...

  4. Medium-energy electrons and heavy ions in Jupiter's magnetosphere - Effects of lower hybrid wave-particle interactions

    Science.gov (United States)

    Barbosa, D. D.

    1986-01-01

    A theory of medium-energy (about keV) electrons and heavy ions in Jupiter's magnetosphere is presented. Lower hybrid waves are generated by the combined effects of a ring instability of neutral wind pickup ions and the modified two-stream instability associated with transport of cool Iogenic plasma. The quasi-linear energy diffusion coefficient for lower hybrid wave-particle interactions is evaluated, and several solutions to the diffusion equation are given. Calculations based on measured wave properties show that the noise substantially modifies the particle distribution functions. The effects are to accelerate superthermal ions and electrons to keV energies and to thermalize the pickup ions on time scales comparable to the particle residence time. The S(2+)/S(+) ratio at medium energies is a measure of the relative contribution from Iogenic thermal plasma and neutral wind ions, and this important quantity should be determined from future measurements. The theory also predicts a preferential acceleration of heavy ions with an accleration time that scales inversely with the root of the ion mass. Electrons accelerated by the process contribute to further reionization of the neutral wind by electron impact, thus providing a possible confirmation of Alfven's critical velocity effect in the Jovian magnetosphere.

  5. Transfer RNA in the hybrid P/E state: correlating molecular dynamics simulations with cryo-EM data.

    Science.gov (United States)

    Li, Wen; Frank, Joachim

    2007-10-16

    Transfer RNA (tRNA) transiently occupies the hybrid P/E state (P/E-tRNA) when mRNA-tRNA are translocated in the ribosome. In this study, we characterize the structure of P/E-tRNA and its interactions with the ribosome by correlating the results from molecular dynamics simulations on free tRNA with the cryo-EM map of P/E-tRNA. In our approach, we show that the cryo-EM map may be interpreted as a conformational average. Along the molecular dynamics trajectories (44 ns, 18 ns, and 18 ns), some of the snapshots prove to be quite close to the observed density. In a representative structure, the CCA (3') arm is uniquely twisted, and the anticodon stem loop is kinked at the junctions to both the anticodon loop and the D stem. In addition, the map shows that the P/E-tRNA is no longer bound to helix H69 of 23S rRNA and is flexible, and the conformations of helices H68 and h44 of 16S rRNA differ from those in the x-ray structure. Thus, our study presents structural and dynamic information on the P/E-tRNA and characterizes its interactions with the translocating ribosome.

  6. Non linear dynamic of Langmuir and electromagnetic waves in space plasmas; Dinamica nao linear de ondas de Langmuir e eletromagneticas em plasmas espaciais

    Energy Technology Data Exchange (ETDEWEB)

    Guede, Jose Ricardo Abalde

    1995-11-01

    The aim of this work is to study the nonlinear dynamics of Langmuir and electromagnetic waves in space plasmas. Firstly, the generalized Zakharov equations are derived which are used to study the hybrid parametric instability involving the generation of daughter Langmuir, electromagnetic and ion-acoustic waves induced by two counter-propagating Langmuir pump waves with different amplitudes based on a coupled dispersion relation. Secondly, starting from the generalized Zakharov equations the linear and nonlinear coupled mode theories of three-wave and four-wave parametric interactions are developed, respectively. In three-waves processes, a Langmuir wave decays into another Langmuir wave and an ion-acoustic wave (electrostatic parametric decay) or into an electromagnetic wave and an ion-acoustic wave (electromagnetic parametric decay). In four-wave (modulational) processes, the interaction involves two wave triplets: in the decay triplet a pump wave couples with a low-frequency wave to generate a Stokes wave, and in the fusion triplets: in the decay triplet a pump wave couples with a low-frequency wave to generate a Stokes wave, and in the fusion triplet the coupling of a pump wave with a low-frequency wave generate an anti-Stokes wave. These modulational processes are convective and resonant processes wherein the low-frequency modes are Eigenmodes of plasma and are known as the stimulated modulational processes. Four such processes are investigated in this thesis: two with Langmuir pump waves (electrostatic and hybrid stimulated modulation processes) and the other two with electromagnetic pump waves (stimulated modulation Brillouin scattering and electromagnetic stimulated modulation process). Applications of the theoretical results in space plasmas are discussed. In particular, it is shown that the electrostatic and electromagnetic parametric decay processes of Langmuir waves can model the generation and modulation of radio emissions and Langmuir waves in the

  7. Characterization of onset of parametric decay instability of lower hybrid waves

    Energy Technology Data Exchange (ETDEWEB)

    Baek, S. G.; Bonoli, P. T.; Parker, R. R.; Shiraiwa, S.; Wallace, G. M.; Porkolab, M.; Brunner, D.; Faust, I. C.; Hubbard, A. E.; LaBombard, B. L.; Lau, C. [MIT Plasma Science and Fusion Center, Cambridge, MA (United States); Takase, Y. [The University of Tokyo, Kashiwa (Japan)

    2014-02-12

    The goal of the lower hybrid current drive (LHCD) program on Alcator C-Mod is to develop and optimize ITER-relevant steady-state plasmas by controlling the current density profile. Using a 4×16 waveguide array, over 1 MW of LH power at 4.6 GHz has been successfully coupled to the plasmas. However, current drive efficiency precipitously drops as the line averaged density (nÐœ„{sub e}) increases above 10{sup 20}m{sup −3}. Previous numerical work shows that the observed loss of current drive efficiency in high density plasmas stems from the interactions of LH waves with edge/scrape-off layer (SOL) plasmas [Wallace et al., Physics of Plasmas 19, 062505 (2012)]. Recent observations of parametric decay instability (PDI) suggest that non-linear effects should be also taken into account to fully characterize the parasitic loss mechanisms [Baek et al., Plasma Phys. Control Fusion 55, 052001 (2013)]. In particular, magnetic configuration dependent ion cyclotron PDIs are observed using the probes near nÐœ„{sub e}≈1.2×10{sup 20}m{sup −3}. In upper single null plasmas, ion cyclotron PDI is excited near the low field side separatrix with no apparent indications of pump depletion. The observed ion cyclotron PDI becomes weaker in inner wall limited plasmas, which exhibit enhanced current drive effects. In lower single null plasmas, the dominant ion cyclotron PDI is excited near the high field side (HFS) separatrix. In this case, the onset of PDI is correlated with the decrease in pump power, indicating that pump wave power propagates to the HFS and is absorbed locally near the HFS separatrix. Comparing the observed spectra with the homogeneous growth rate calculation indicates that the observed ion cyclotron instability is excited near the plasma periphery. The incident pump power density is high enough to overcome the collisional homogeneous threshold. For C-Mod plasma parameters, the growth rate of ion sound quasi-modes is found to be typically smaller by an

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-11-01

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

  9. A unified formulation for guided-wave propagation in multi-layered mixed anisotropic-isotropic hybrid aerospace composites

    Science.gov (United States)

    Barazanchy, Darun; Giurgiutiu, Victor

    2016-04-01

    A unified approach was formulated to predict guided-wave propagation in a material regardless its degree of anisotropy, thereby having one solution method for both isotropic and anisotropic material. The unified approach was based on the coupled eigenvalue problem derived from Chirstoffels equation for a lamina. The eigenvalue problem yielded a set of eigenvalues, and corresponding eigenvectors that were used to obtain the stress-displacement matrix. The dispersion curves were obtained by applying the traction free boundary conditions to the stress-displacement matrix, and searching for sign changes in the complex determinant of the matrix. To search for sign changes, hence the velocity-wavenumber pairs which yielded a solution to the problem, the real and imaginary part of the complex determinant had to change sign simultaneously. A phase angle approach was, therefore, developed and successfully applied. A refinement algorithm was applied to refine the accuracy of the solution without increasing the computational time significantly. A high accuracy was required to calculated the correct partial-wave participation factors. The obtained partial-wave participation factors were used to calculate the modeshape through the thickness for each velocity-wavenumber pair. To identify the different wave types, A0, S0, SHS0, SHA0, a modeshape identification was applied successfully. The unified approach was evaluated for hybrid aerospace composites. In addition, the two most common solution methods: (i) the global matrix method; and (ii) the transfer matrix method were applied, and a comparative study between the different methods was performed.

  10. Excitation of whistler waves below the lower hybrid frequency by a loop antenna located in an enhanced density duct

    Science.gov (United States)

    Kudrin, Alexander V.; Ostafiychuk, Oleg M.; Zaboronkova, Tatyana M.

    2017-08-01

    Whistler wave radiation from a loop antenna located in a cylindrical duct with enhanced plasma density is considered in the case where the wave frequency is less than the lower hybrid frequency. Using the full-wave formulation, the total radiation resistance and the partial radiation resistances corresponding to guided eigenmodes of such a duct and unguided waves radiating to the background magnetoplasma are calculated and analyzed as functions of the plasma and source parameters. The emphasis is placed on the radiation characteristics of the considered source in the presence of an artificial near-antenna duct that can be created during active experiments in the ionosphere. Conditions are revealed under which the total radiation resistance is predominantly determined by the excitation of the eigenmodes of the duct. It is shown that the presence of an enhanced density duct can lead to a notable increase in the radiation resistance of a loop antenna in the discussed frequency range even if the duct is rather narrow and capable of guiding only a single low-order eigenmode. The results obtained can be helpful in understanding the basic features of excitation of the ducted whistlers and planning the related ionospheric and laboratory experiments.

  11. Hybrid ANFIS with ant colony optimization algorithm for prediction of shear wave velocity from a carbonate reservoir in Iran

    Directory of Open Access Journals (Sweden)

    Hadi Fattahi

    2016-12-01

    Full Text Available Shear wave velocity (Vs data are key information for petrophysical, geophysical and geomechanical studies. Although compressional wave velocity (Vp measurements exist in almost all wells, shear wave velocity is not recorded for most of elderly wells due to lack of technologic tools. Furthermore, measurement of shear wave velocity is to some extent costly. This study proposes a novel methodology to remove aforementioned problems by use of hybrid adaptive neuro fuzzy inference system (ANFIS with ant colony optimization algorithm (ACO based on fuzzy c–means clustering (FCM and subtractive clustering (SCM. The ACO is combined with two ANFIS models for determining the optimal value of its user–defined parameters. The optimization implementation by the ACO significantly improves the generalization ability of the ANFIS models. These models are used in this study to formulate conventional well log data into Vs in a quick, cheap, and accurate manner. A total of 3030 data points was used for model construction and 833 data points were employed for assessment of ANFIS models. Finally, a comparison among ANFIS models, and six well–known empirical correlations demonstrated ANFIS models outperformed other methods. This strategy was successfully applied in the Marun reservoir, Iran.

  12. Technico-economical analysis of a hybrid wave power-air compression storage system

    OpenAIRE

    Hernandez-Torres, David; Bridier, Laurent; David, Mathieu; Lauret, Philippe; Ardiale, Thomas

    2015-01-01

    International audience; This paper presents a technico-economical analysis of a Pelamis wave power generator coupled with a proposed air compression storage system. Ocean wave measurements and forecasts are used from a site near the city of Saint-Pierre in Réunion island, France. The insular context requires both smoothing and forecast of the output power from the wave power system. The storage system is a solution to meet this requirement. Several power network services are defined by the ut...

  13. Loop heating by D.C. electric current and electromagnetic wave emissions simulated by 3-D EM particle zone

    Science.gov (United States)

    Sakai, J. I.; Zhao, J.; Nishikawa, K.-I.

    1994-01-01

    We have shown that a current-carrying plasma loop can be heated by magnetic pinch driven by the pressure imbalance between inside and outside the loop, using a 3-dimensional electromagnetic (EM) particle code. Both electrons and ions in the loop can be heated in the direction perpendicular to the ambient magnetic field, therefore the perpendicular temperature can be increased about 10 times compared with the parallel temperature. This temperature anisotropy produced by the magnetic pinch heating can induce a plasma instability, by which high-frequency electromagnetic waves can be excited. The plasma current which is enhanced by the magnetic pinch can also excite a kinetic kink instability, which can heat ions perpendicular to the magnetic field. The heating mechanism of ions as well as the electromagnetic emission could be important for an understanding of the coronal loop heating and the electromagnetic wave emissions from active coronal regions.

  14. Jacobian Elliptic Function Method and Solitary Wave Solutions for Hybrid Lattice Equation

    Institute of Scientific and Technical Information of China (English)

    WANG Rui-Min; DAI Chao-Qing; ZHANG Jie-Fang

    2006-01-01

    In this paper, we have successfully extended the Jacobian elliptic function expansion approach to nonlinear differential-difference equations. The Hybrid lattice equation is chosen to illustrate this approach. As a consequence,twelve families of Jacobian elliptic function solutions with different parameters of the Hybrid lattice equation are obtained.When the modulus m → 1 or 0, doubly-periodic solutions degenerate to solitonic solutions and trigonometric function solutions, respectively.

  15. Identification of waves in the lower-hybrid frequency range in the scrape-off layer plasma of Alcator C-Mod

    Science.gov (United States)

    Shinya, Takahiro; Gyou Baek, Seung; Wallace, Gregory M.; Shiraiwa, Syun'ichi; Takase, Yuichi; Parker, Ronald R.; Bonoli, Paul T.; Brunner, Dan; Faust, Ian; LaBombard, Brian L.; Wukitch, Steve

    2017-03-01

    Polarization resolved measurements of the parallel refractive index {{N}\\parallel}\\equiv c{{k}\\parallel}/ω of the driven RF waves in the lower hybrid (LH) range of frequencies are performed using arrays of RF magnetic probes in the scrape-off layer plasma of Alcator C-Mod. The measured {{N}\\parallel} of the RF magnetic field component parallel to the background magnetic field is about  -1.6, which corresponds to the peak of the launched LH {{N}\\parallel} spectrum. Based on the wave dispersion relationship, this wave is identified as the LH slow wave. On the other hand, the RF magnetic field component perpendicular to the magnetic field is found to have a lower {{N}\\parallel} of  -1.2, and is detected only near the last closed flux surface. This wave is identified as the LH fast wave generated by slow-fast wave mode conversion.

  16. Self-Adaptive Power Control Mechanism in D2D Enabled Hybrid Cellular Network with mmWave Small Cells:An Optimization Approach

    OpenAIRE

    Raza, Syed Ahsan; Hassan, Syed Ali; Pervaiz, Haris Bin; Ni, Qiang; Musavian, Leila

    2016-01-01

    Millimeter wave (mmWave) and Device-to-Device (D2D) communications have been considered as the key enablers of the next generation networks. We consider a D2D-enabled hybrid cellular network compromising of μW macro-cells coexisting with mmWave small cells. We investigate the dynamic resource sharing in downlink transmission to maximize the energy efficiency (EE) of the priority, or cellular users (CUs), that are opportunistically served by either macrocells or mmWave small cells, while satis...

  17. A wave-shaped hybrid piezoelectric and triboelectric nanogenerator based on P(VDF-TrFE) nanofibers.

    Science.gov (United States)

    Chen, Xuexian; Han, Mengdi; Chen, Haotian; Cheng, Xiaoliang; Song, Yu; Su, Zongming; Jiang, Yonggang; Zhang, Haixia

    2017-01-19

    A wave-shaped hybrid nanogenerator (NG) with mutually enhanced piezoelectric and triboelectric output is presented in this work. By sandwiching piezoelectric P(VDF-TrFE) nanofibers between wave-shaped Kapton films, the device forms a three-layer structure, which can generate piezoelectric and triboelectric outputs simultaneously in one press and release cycle. Through systematic situational analysis and experimental validation, the three-layer structure can achieve obvious improvement of the output performance for both parts. When triggered with 4 Hz external force, the piezoelectric part generates a peak output and current of 96 V and 3.8 μA, which is ∼2 times higher than its initial output. Meanwhile, the performance of triboelectric parts also increases 8 V and 16 V with the assistance of piezoelectric potential. The enhanced high output enables the hybrid nanogenerator to instantaneously light up LEDs and charges capacitors quickly, which shows extensive application prospects in the field of self-powered systems or sensor networks.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-10-15

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

  19. Development of numerical methods to calculate the propagation and the absorption of the hybrid wave in tokamaks; Developpement des methodes numeriques pour la resolution de la propagation et de l`absorption de l`onde hybride dans les tokamaks

    Energy Technology Data Exchange (ETDEWEB)

    Sebelin, E

    1997-12-15

    Full-wave calculations based on trial functions are carried out for solving the lower hybrid current drive problem in tokamaks. A variational method is developed and provides an efficient system to describe in a global manner both the propagation and the absorption of the electromagnetic waves in plasmas. The calculation is fully carried out in the case of circular and concentric flux surfaces. The existence and uniqueness of the solution of the wave propagation equation is mathematically proved. The first realistic simulations are performed for the high aspect ratio tokamak TRIAM-1M. It is checked that the main features of the lower-hybrid wave dynamics are well described numerically. (A.C.) 81 refs.

  20. Impact of Ion Acoustic Wave Instabilities in the Flow Field of a Hypersonic Vehicle on EM Signals

    Science.gov (United States)

    Mudaliar, Saba; Sotnikov, Vladimir

    2016-10-01

    Flow associated with a high speed air vehicle (HSAV) can get partially ionized. In the absence of external magnetic field the flow field turbulence is due to ion acoustic wave (IAW) instabilities. Our interest is in studying the impact of this turbulence on the radiation characteristics of EM signals from the HSAV. We decompose the radiated signal into coherent and diffuse parts. We find that the coherent part has the same spectrum as that of the source signal, but it is distorted because of dispersive coherent attenuation. The diffuse part is expressed as a convolution (in wavenumber and frequency) of the source signal with the spectrum of electron density fluctuations. This is a constrained convolution in the sense that the spectrum has to satisfy the IAW dispersion relation. A quantity that characterizes the flow is the mean free path (MFP). When the MFP is large compared to the thickness of the flow the coherent part is significant. If the MFP is larger than the thickness of the flow the diffuse part is the dominant part of the received signal. In the special case when the source signal frequency is close the electron plasma frequency, there can exist in the flow region Langmuir modes in addition to the EM modes. The radiation characteristics of EM source signals from the HSAV in this case are quite different.

  1. Hibridismo e simultaneidade em The Famished Road de Ben Okri = Hybridity and simultaneousness in The Famished Road, by Ben Okri

    Directory of Open Access Journals (Sweden)

    Divanize Carbonieri

    2008-01-01

    Full Text Available Neste artigo, analisa-se o romance The famished road (1991 de Ben Okri, um autor nigeriano que vive e publica suas obras na Inglaterra. O objetivo é demonstrar que é uma obra híbrida entre concepções de mundo e formas de narrar diferentes, características de diversas tradições literárias e orais. A análise é baseada nos conceitos de hibridismo, tradução cultural e cosmopolitismo vernáculo de Bhabha (1990 e 2000, além de textos teóricos sobre a cultura iorubá e a literatura africana, como Soyinka (1990, Okpewho (1983 e Quayson (2002, entre outros. Também são apresentadas as especificidades dorealismo mágico africano, um modo narrativo que reúne, em si, estratégias e técnicas distintas, com a discussão de autores como Cooper (2004, Slemon (1988 e Walter (1993.This article analyzes The famished road (1991 by Ben Okri, a Nigerian author who lives and publishes his works in England. Its main goal is to demonstrate that it is a hybrid work among different worldviews and narrative forms, characteristic of diverse literary andoral traditions. The analysis is based on concepts of hybridity, cultural translation and vernacular cosmopolitanism by Bhabha (1990 and 2000, as well as on theoretical texts about Yoruba culture and African literature, such as Soyinka (1990, Okpewho (1983, andQuayson (2002, among others. Specificities of African magical realism, a narrative mode that combines distinct strategies and techniques, are also presented with the discussion of authors, such as Cooper (2004, Slemon (1988, and Walter (1993.

  2. Electron Acceleration by High Power Radio Waves in the Ionosphere

    Science.gov (United States)

    Bernhardt, Paul

    2012-10-01

    At the highest ERP of the High Altitude Auroral Research Program (HAARP) facility in Alaska, high frequency (HF) electromagnetic (EM) waves in the ionosphere produce artificial aurora and electron-ion plasma layers. Using HAARP, electrons are accelerated by high power electrostatic (ES) waves to energies >100 times the thermal temperature of the ambient plasma. These ES waves are driven by decay of the pump EM wave tuned to plasma resonances. The most efficient acceleration process occurs near the harmonics of the electron cyclotron frequency in earth's magnetic field. Mode conversion plays a role in transforming the ES waves into EM signals that are recorded with ground receivers. These diagnostic waves, called stimulated EM emissions (SEE), show unique resonant signatures of the strongest electron acceleration. This SEE also provides clues about the ES waves responsible for electron acceleration. The electron gas is accelerated by high frequency modes including Langmuir (electron plasma), upper hybrid, and electron Bernstein waves. All of these waves have been identified in the scattered EM spectra as downshifted sidebands of the EM pump frequency. Parametric decay is responsible low frequency companion modes such as ion acoustic, lower hybrid, and ion Bernstein waves. The temporal evolution of the scattered EM spectrum indicates development of field aligned irregularities that aid the mode conversion process. The onset of certain spectral features is strongly correlated with glow plasma discharge structures that are both visible with the unaided eye and detectable using radio backscatter techniques at HF and UHF frequencies. The primary goals are to understand natural plasma layers, to study basic plasma physics in a unique ``laboratory with walls,'' and to create artificial plasma structures that can aid radio communications.

  3. Discursos híbridos nas memórias das licenciaturas em ciências em uma instituição universitária Hybrid Speech in the memories of Licentiates in Sciences in a university institution

    Directory of Open Access Journals (Sweden)

    Maria Inês Petrucci Rosa

    2011-01-01

    Full Text Available Esse trabalho investiga memórias de uma instituição universitária com tradição em formação docente no que se refere aos processos de reformulação curricular da última década. Para isso, foram entrevistados professores e professoras dos programas de licenciaturas em ciências, numa perspectiva metodológica afinada com a noção de rememoração e de narrativa em W. Benjamin. Os discursos produzidos durante a reconfiguração curricular das licenciaturas em questão evidenciaram hibridismos produzidos nos campos disciplinares em disputa no currículo em transformação.This work investigates the memories of a university with a tradition in teacher education, about the curricular changes that have happened during the last decade. For this, professors of science teacher education programs were interviewed, in a methodological approach influenced by the notion of remembering and narrative by W. Benjamin. Their speech showed a hybridism of discourse produced in the disciplinary fields which were disputed space during curricular change.

  4. Offshore energy structures for wind power, wave energy and hybrid marine platforms

    CERN Document Server

    Karimirad, Madjid

    2014-01-01

    This book provides all the key information needed to design offshore structures for renewable energy applications successfully. Suitable for practicing engineers and students, the author conveys design principles and best practices in a clear, concise manner, focusing on underlying physics while eschewing complicated mathematical detail. The text connects underlying scientific theory with industry standards and practical implementation issues for offshore wind turbines, wave energy converters and current turbines. Combined concepts such as wave-wind energy platforms are discussed, as well. Cov

  5. Boundaries of Parametric Gain due to Four-wave Mixing in Hybrid Photonic Crystal Fibers

    DEFF Research Database (Denmark)

    Petersen, Sidsel Rübner; Lægsgaard, Jesper; Alkeskjold, Thomas Tanggaard

    2014-01-01

    Parametric gain by four-wave mixing is considered in photonic crystal fibers for an undepleted pump. The mode distributions are wavelength dependent, thus field overlap integrals cannot be simplified, and an extended gain region is observed......Parametric gain by four-wave mixing is considered in photonic crystal fibers for an undepleted pump. The mode distributions are wavelength dependent, thus field overlap integrals cannot be simplified, and an extended gain region is observed...

  6. A hybrid scheme for absorbing edge reflections in numerical modeling of wave propagation

    KAUST Repository

    Liu, Yang

    2010-03-01

    We propose an efficient scheme to absorb reflections from the model boundaries in numerical solutions of wave equations. This scheme divides the computational domain into boundary, transition, and inner areas. The wavefields within the inner and boundary areas are computed by the wave equation and the one-way wave equation, respectively. The wavefields within the transition area are determined by a weighted combination of the wavefields computed by the wave equation and the one-way wave equation to obtain a smooth variation from the inner area to the boundary via the transition zone. The results from our finite-difference numerical modeling tests of the 2D acoustic wave equation show that the absorption enforced by this scheme gradually increases with increasing width of the transition area. We obtain equally good performance using pseudospectral and finite-element modeling with the same scheme. Our numerical experiments demonstrate that use of 10 grid points for absorbing edge reflections attains nearly perfect absorption. © 2010 Society of Exploration Geophysicists.

  7. Efficient Hybrid-Spectral Model for Fully Nonlinear Numerical Wave Tank

    DEFF Research Database (Denmark)

    Christiansen, Torben; Bingham, Harry B.; Engsig-Karup, Allan Peter;

    2013-01-01

    A new hybrid-spectral solution strategy is proposed for the simulation of the fully nonlinear free surface equations based on potential flow theory. A Fourier collocation method is adopted horisontally for the discretization of the free surface equations. This is combined with a modal Chebyshev T...

  8. Wave transmission through two-dimensional structures by the hybrid FE/WFE approach

    Science.gov (United States)

    Mitrou, Giannoula; Ferguson, Neil; Renno, Jamil

    2017-02-01

    The knowledge of the wave transmission and reflection characteristics in connected two-dimensional structures provides the necessary background for many engineering prediction methodologies. Extensive efforts have previously been exerted to investigate the propagation of waves in two-dimensional periodic structures. This work focuses on the analysis of the wave propagation and the scattering properties of joined structures comprising of two or more plates. The joint is modelled using the finite element (FE) method whereas each (of the joined) plate(s) is modelled using the wave and finite element (WFE) method. This latter approach is based on post-processing a standard FE model of a small segment of the plate using periodic structure theory; the FE model of the segment can be obtained using any commercial/in-house FE package. Stating the equilibrium and continuity conditions at the interfaces and expressing the motion in the plates in terms of the waves in each plate yield the reflection and transmission matrices of the joint. These can then be used to obtain the response of the whole structure, as well as investigating the frequency and incidence dependence for the flow of power in the system.

  9. Contrast improvement of continuous wave diffuse optical tomography reconstruction by hybrid approach using least square and genetic algorithm.

    Science.gov (United States)

    Patra, Rusha; Dutta, Pranab K

    2015-07-01

    Reconstruction of the absorption coefficient of tissue with good contrast is of key importance in functional diffuse optical imaging. A hybrid approach using model-based iterative image reconstruction and a genetic algorithm is proposed to enhance the contrast of the reconstructed image. The proposed method yields an observed contrast of 98.4%, mean square error of 0.638×10⁻³, and object centroid error of (0.001 to 0.22) mm. Experimental validation of the proposed method has also been provided with tissue-like phantoms which shows a significant improvement in image quality and thus establishes the potential of the method for functional diffuse optical tomography reconstruction with continuous wave setup. A case study of finger joint imaging is illustrated as well to show the prospect of the proposed method in clinical diagnosis. The method can also be applied to the concentration measurement of a region of interest in a turbid medium.

  10. Hybrid interferometer with nonlinear four-wave mixing process and linear beam splitter.

    Science.gov (United States)

    Liu, Shengshuai; Jing, Jietai

    2017-07-10

    Optical interferometer has played an important role in optics. Up to now, many kinds of interferometers have been realized and found their applications. In this letter, we experimentally construct an interferometer by using parametric amplifier as a wave splitter and beam splitter as a wave combiner. We make measurements of interference fringes and explore the relationships between the interference visibility of the interferometer and various system parameters, such as the gain of the parametric amplifier, the one-photon detuning and the temperature of the Rb-85 vapor cell.

  11. Analysis and design of hybrid leaky-wave antennas loaded with frequency selective surfaces

    OpenAIRE

    García Vigueras, María

    2013-01-01

    [SPA] En esta tesis se propone una nueva antena de tipo Leaky-Wave (Leaky Wave Antenna, LWA). Estas antenas han recibido mucha atención en las últimas décadas por ser altamente directivas. En concreto, constituyen una solución especialmente atractiva para aplicaciones que requieran altas prestaciones y precisión, como en sistemas de comunicación por satélite y radar. Concretamente, las LWAs consideradas en esta tesis se basan en la radiación producida por una onda de fuga que se propaga por ...

  12. Wave dispersion in the hybrid-Vlasov model: Verification of Vlasiator

    OpenAIRE

    Kempf, Yann; Pokhotelov, Dimitry; von Alfthan, Sebastian; Vaivads, Andris; Palmroth, Minna; Koskinen, Hannu E. J.

    2013-01-01

    Vlasiator is a new hybrid-Vlasov plasma simulation code aimed at simulating the entire magnetosphere of the Earth. The code treats ions (protons) kinetically through Vlasov's equation in the six-dimensional phase space while electrons are a massless charge-neutralizing fluid [M. Palmroth et al., Journal of Atmospheric and Solar-Terrestrial Physics 99, 41 (2013); A. Sandroos et al., Parallel Computing 39, 306 (2013)]. For first global simulations of the magnetosphere, it is critical to verify ...

  13. The Nonlinear Coupling of Electromagnetic Ion Cyclotron and Lower Hybrid Waves in the Ring Current Region: The Magnetic Storm May 1-7 1998

    Science.gov (United States)

    Khazanov, G. V.; Krivorutsky, E.; Gamayunov, K.; Avanov, L.

    2003-01-01

    The excitation of lower hybrid waves (LHWs) is a widely discussed mechanism of interaction between plasma species in space, and is one of the unresolved questions of magnetospheric multi-ion plasmas. In this paper we present the morphology, dynamics, and level of LHW activity generated by electromagnetic ion cyclotron (EMIC) waves during the May 2-7, 1998 storm period on the global scale. The LHWs were calculated based on our newly developed self-consistent model that couples the system of two kinetic equations: one equation describes the ring current (RC) ion dynamic, and another equation describes the evolution of EMIC waves. It is found that the LHWs are excited by helium ions due to their mass dependent drift in the electric field of EMIC waves. The level of LHW activity is calculated assuming that the induced scattering process is the main saturation mechanism for these waves. The calculated LHWs electric fields are consistent with the observational data.

  14. Internal transport barrier triggered by non-linear lower hybrid wave deposition under condition of beam-driven toroidal rotation

    Science.gov (United States)

    Gao, Q. D.; Budny, R. V.

    2015-03-01

    By using gyro-Landau fluid transport model (GLF23), time-dependent integrated modeling is carried out using TRANSP to explore the dynamic process of internal transport barrier (ITB) formation in the neutral beam heating discharges. When the current profile is controlled by LHCD (lower hybrid current drive), with appropriate neutral beam injection, the nonlinear interplay between the transport determined gradients in the plasma temperature (Ti,e) and toroidal velocity (Vϕ) and the E×B flow shear (including q-profile) produces transport bifurcations, generating spontaneously a stepwise growing ITB. In the discharge, the constraints imposed by the wave propagation condition causes interplay of the LH driven current distribution with the plasma configuration modification, which constitutes non-linearity in the LH wave deposition. The non-linear effects cause bifurcation in LHCD, generating two distinct quasi-stationary reversed magnetic shear configurations. The change of current profile during the transition period between the two quasi-stationary states results in increase of the E×B shearing flow arising from toroidal rotation. The turbulence transport suppression by sheared E×B flow during the ITB development is analysed, and the temporal evolution of some parameters characterized the plasma confinement is examined. Ample evidence shows that onset of the ITB development is correlated with the enhancement of E×B shearing rate caused by the bifurcation in LHCD. It is suggested that the ITB triggering is associated with the non-linear effects of the LH power deposition.

  15. A TVD-WAF-based hybrid finite volume and finite difference scheme for nonlinearly dispersive wave equations

    Directory of Open Access Journals (Sweden)

    Jing Yin

    2015-07-01

    Full Text Available A total variation diminishing-weighted average flux (TVD-WAF-based hybrid numerical scheme for the enhanced version of nonlinearly dispersive Boussinesq-type equations was developed. The one-dimensional governing equations were rewritten in the conservative form and then discretized on a uniform grid. The finite volume method was used to discretize the flux term while the remaining terms were approximated with the finite difference method. The second-order TVD-WAF method was employed in conjunction with the Harten-Lax-van Leer (HLL Riemann solver to calculate the numerical flux, and the variables at the cell interface for the local Riemann problem were reconstructed via the fourth-order monotone upstream-centered scheme for conservation laws (MUSCL. The time marching scheme based on the third-order TVD Runge-Kutta method was used to obtain numerical solutions. The model was validated through a series of numerical tests, in which wave breaking and a moving shoreline were treated. The good agreement between the computed results, documented analytical solutions, and experimental data demonstrates the correct discretization of the governing equations and high accuracy of the proposed scheme, and also conforms the advantages of the proposed shock-capturing scheme for the enhanced version of the Boussinesq model, including the convenience in the treatment of wave breaking and moving shorelines and without the need for a numerical filter.

  16. Hybrid Eulerian and Lagrangian Simulation of Steep and Breaking Waves and Surface Fluxes in High Winds

    Science.gov (United States)

    2012-09-30

    codes are parallelized using message passing interface (MPI) based on domain decomposition. For SPH , graphics processing unit (GPU) computing, which is...aims at developing a numerical capability using a Lagrangian Smoothed Particle Hydrodynamics ( SPH ) method and an Eulerian Level-Set Method (LSM) for...the SPH and LSM with environmental input provided by coupled wind and wave simulations at far field; (2) Use the numerical method developed in (1

  17. Separating Internal Waves and Vortical Motions: Analysis of LatMix -EM-APEX Float Measurements

    Science.gov (United States)

    2015-09-30

    Washington 98105 Phone: (206) 685-1079 fax: (206) 543-6785 email: lien@apl.washington.edu Thomas B. Sanford Applied Physics Laboratory and School ...project is to separate internal waves and vortical motions. These two processes coexist at small spatial scales (Müller 1984). However, they have distinct

  18. Four-wave mixing stability in hybrid photonic crystal fibers with two zero-dispersion wavelengths.

    Science.gov (United States)

    Sévigny, Benoit; Vanvincq, Olivier; Valentin, Constance; Chen, Na; Quiquempois, Yves; Bouwmans, Géraud

    2013-12-16

    The four-wave mixing process in optical fibers is generally sensitive to dispersion uniformity along the fiber length. However, some specific phase matching conditions show increased robustness to longitudinal fluctuations in fiber dimensions, which affect the dispersion, even for signal and idler wavelengths far from the pump. In this paper, we present the method by which this point is found, how the fiber design characteristics impact on the stable point and demonstrate the stability through propagation simulations using the non-linear Schrödinger equation.

  19. Microwave absorbance properties of zirconium–manganese substituted cobalt nanoferrite as electromagnetic (EM) wave absorbers

    Energy Technology Data Exchange (ETDEWEB)

    Khan, Kishwar, E-mail: kknano@hotmail.com; Rehman, Sarish

    2014-02-01

    Highlights: • Good candidates for EM materials with low reflectivity. • Good candidates for broad bandwidth at microwave frequency. • Microwave absorbing bandwidth was modulated simply by manipulating the Zr–Mn. • Higher the Zr–Mn content, the higher absorption rates for the electromagnetic radiation. • The predicted reflection loss shows that this can be used for thin ferrite absorber. - Abstract: Nanocrystalline Zr–Mn (x) substituted Co ferrite having chemical formula CoFe{sub 2−2x}Zr{sub x}Mn{sub x}O{sub 4} (x = 0.1–0.4) was prepared by co-precipitation technique. Combining properties such as structural, electrical, magnetic and reflection loss characteristics. Crystal structure and surface morphology of the calcined samples were characterized by X-ray diffraction analysis (XRD) and scanning electron microscopy (SEM). By using two point probe homemade resistivity apparatus to find resistivity of the sample. Electromagnetic (EM) properties are measured through RF impedance/materials analyzer over 1 MHz–3 GHz. The room-temperature dielectric measurements show dispersion behavior with increasing frequency from 100 Hz to 3 MHz. Magnetic properties confirmed relatively strong dependence of saturation magnetization on Zr–Mn composition. Curie temperature is also found to decrease linearly with addition of Zr–Mn. Furthermore, comprehensive analysis of microwave reflection loss (RL) is carried out as a function of substitution, frequency, and thickness. Composition accompanying maximum microwave absorption is suggested.

  20. Modeling wave trains in coastal regions; Modelagem de trens de ondas em regioes costeiras

    Energy Technology Data Exchange (ETDEWEB)

    Luz, Ana M.S.; Nachbin, A. [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Inst. de Matematica Pura e Aplicada (IMPA)

    2008-07-01

    Our goal is to present a model that captures how the sea bottom topography or submarine structures can influence the evolution of water wave trains over a varying topography at intermediate depth. To obtain such a model, we consider Euler equations for inviscid fluids and we perform the asymptotic simplification of the nonlinear potential theory equations together with the method of multiple scales to get a reduced model. Such a model is called reduced because it simplifies nonlinear potential theory from two spatial dimensions to one dimension along the free boundary. We consider a varying topography at the bottom and/or the presence of submarine structures together with a free boundary at the surface of the sea. For modeling such a geometry we transform our Cartesian system into curvilinear coordinates through a conformal mapping that maps the original physical domain into a simpler domain (a strip). This modeling strategy allows us to capture and understand the dynamics of water waves in regions where offshore exploration activity already exists or not. Through an efficient model we can get important information regarding the dynamics of waves in coastal regions and also questions on the viability of oil and gas recovery in these regions. (author)

  1. Ultrathin Terahertz Quarter-wave plate based on Split Ring Resonator and Wire Grating hybrid Metasurface

    Science.gov (United States)

    Nouman, Muhammad Tayyab; Hwang, Ji Hyun; Jang, Jae-Hyung

    2016-12-01

    Planar metasurface based quarter-wave plates offer various advantages over conventional waveplates in terms of compactness, flexibility and simple fabrication; however they offer very narrow bandwidth of operation. Here, we demonstrate a planar terahertz (THz) metasurface capable of linear to circular polarization conversion and vice versa in a wide frequency range. The proposed metasurface is based on horizontally connected split ring resonators and is realized on an ultrathin (0.05λ) zeonor substrate. The fabricated quarter waveplate realizes linear to circular polarization conversion in two broad frequency bands comprising 0.64-0.82 THz and 0.96-1.3 THz with an insertion loss ranging from -3.9 to -10 dB. By virtue of ultrathin sub wavelength thickness, the proposed waveplate design is well suited for application in near field THz optical systems. Additionally, the proposed metasurface design offers novel transmission phase characteristics that present further opportunities to realize dynamic polarization control of incident waves.

  2. Seismic Wave Scattering Through a Compressed Hybrid BEM/FEM Method

    CERN Document Server

    Guarín-Zapata, Nicolás; Jaramillo, Juan

    2014-01-01

    Approximated numerical techniques, for the solution of the elastic wave scattering problem over semi-infinite domains are reviewed. The approximations involve the representation of the half-space by a boundary condition described in terms of 2D boundary element discretizations. The classical BEM matrices are initially re-written into the form of a dense dynamic stiffness matrix and later approximated to a banded matrix. The resulting final banded matrix is then used like a standard finite element to solve the wave scattering problem at lower memory requirements. The accuracy of the reviewed methods is benchmarked against the classical problems of a semi-circular and a rectangular canyon. Results are presented in the time and frequency domain, as well as in terms of relative errors in the considered approximations. The main goal of the paper is to give the analyst a method that can be used at the practising level where an approximate solution is enough in order to support engineering decisions.

  3. 700-W diffusion-cooled large-area 40.68-MHz excited CO2 laser employing split-wave hybrid confocal resonator

    Science.gov (United States)

    Vitruk, Peter; Schemmer, James; Byron, Stan

    1998-09-01

    A novel non-waveguide, non-free-space CO2 laser resonator cavity, referred to as the split-wave hybrid (SWH) resonator, is described. Traditional resonator mirrors combined with two specially designed light reflecting electrode walls, which enclose the active medium, form the SWH resonator cavity. Light reflecting walls in the split-wave resonator act as wave-front-splitting mirrors in an interferometer, similar to a Fresnel double mirror or Lloyd mirror interferometer. Wave- front of the intra-cavity laser beam is significantly tilted with respect to the resonator walls, which facilitates lowest order mode selection in this resonator. Additionally, electrode wall surfaces contain discontinuities, which further enhances non-waveguide mode discrimination in the SWH resonator.

  4. Hybrid Model Representation of a TLP Including Flexible Topsides in Non-Linear Regular Waves

    Directory of Open Access Journals (Sweden)

    Christof Wehmeyer

    2014-08-01

    Full Text Available The rising demand for renewable energy solutions is forcing the established industries to expand and continue evolving. For the wind energy sector, the vast resources in deep sea locations have encouraged research towards the installation of turbines in deeper waters. One of the most promising technologies able to solve this challenge is the floating wind turbine foundation. For the ultimate limit state, where higher order wave loads have a significant influence, a design tool that couples non-linear excitations with structural dynamics is required. To properly describe the behavior of such a structure, a numerical model is proposed and validated by physical test results. The model is applied to a case study of a tension leg platform with a flexible topside mimicking the tower and a lumped mass mimicking the rotor-nacelle assembly. The model is additionally compared to current commercial software, where the need for the coupled higher order dynamics proposed in this paper becomes evident.

  5. Fabrication of two-color annular hybrid wave plate for three-dimensional super-resolution microscopy

    Science.gov (United States)

    Kumagai, Hiroshi; Iketaki, Yoshinori; Jahn, Kornel; Bokor, Nador

    2016-03-01

    In super-resolution microscopy, we use fluorescence depletion, where an erase beam quenches a molecule in the S1 state generated by a pump beam, and then prevents fluorescence from the S1 state. When a tight doughnut shaped erase beam with is focused on the dyed sample together with a Gaussian pump beam, the remaining fluorescence spot in the focal plane becomes smaller than the diffraction-limited size. Applying destructive interference to the erase beam, erase beam has a minute three-dimensional dark spot surrounded by the light near the focal region. Since this spot introduces fluorescence depletion along the optical axis as in the focal plane, we can achieve three-dimensional super-resolution microscopy. However, to overcome the diffraction limit, an extremely precise optical alignment is required for projecting the focused pump beam into the dark spot of the erase beam. To resolve this technical issue, we fabricated a two-color annular hybrid wave plate (TAHWP) by combining two multi-order wave quartz plates. Although the pump and erase beams co-axially pass through the plate; the pump beam retains its original Gaussian shape, while the erase beam undergoes destructive interference. Inserting the TAHWP into a commercial scanning laser microscope, a three-dimensional spherical fluorescence spot with a volume of (~100 nm)3 can be created. Beside eliminating alignment problems and yielding a compact setup, the TAHWP makes our proposed method very suitable for commercial microscope systems. In this study, we report about detailed fabrication procedure and three-dimensional image properties given by the TAHWP.

  6. Characterization of the onset of ion cyclotron parametric decay instability of lower hybrid waves in a diverted tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Baek, S. G., E-mail: sgbaek@mit.edu; Parker, R. R.; Shiraiwa, S.; Wallace, G. M.; Bonoli, P. T.; Porkolab, M.; Brunner, D.; Faust, I. C.; Hubbard, A. E.; LaBombard, B.; Lau, C. [MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139 (United States); Takase, Y. [University of Tokyo, Kashiwa 277-8561 (Japan)

    2014-06-15

    The goal of the lower hybrid current drive (LHCD) program on Alcator C-Mod is to develop and optimize reactor-relevant steady-state plasmas by controlling current density profile. However, current drive efficiency precipitously decreases as the line averaged density (n{sup ¯}{sub e}) increases above ∼1 × 10{sup 20} m{sup −3}. Previous simulations show that the observed loss of current drive efficiency in high density plasmas stems from the interactions of LH waves with edge/scrape-off layer plasmas [Wallace et al., Phys. Plasmas 19, 062505 (2012)]. A recent observation [Baek et al., Plasma Phys. Controlled Fusion 55, 052001 (2013)] shows that the configuration dependent ion cyclotron parametric decay instability (PDI) is excited in the density range where the discrepancy between the experiments and simulations remains. Comparing the observed spectra with the homogeneous growth rate spectra indicates that the observed ion cyclotron PDI can be excited not only at the low-field-side but also at the high-field-side (HFS) edge of the tokamak. The model analysis shows that a relevant PDI process to Alcator C-Mod LHCD experiments is decay into ion cyclotron quasi-mode driven by parallel coupling. The underlying cause of the observed onset of ion cyclotron PDI is likely due to the weaker radial penetration of the LH wave in high density plasmas, which can lead to enhanced convective growth. Configuration-dependent PDIs are found to be correlated with different edge density profiles in different magnetic configurations. While the HFS edge of the tokamak can be potentially susceptible to PDI, as evidenced by experimental observations and ray-tracing analyses, enhancing single-pass absorption is expected to help recover the LHCD efficiency at reactor-relevant densities because it could suppress several parasitic loss mechanisms that are exacerbated in multi-pass regimes.

  7. Internal transport barrier triggered by non-linear lower hybrid wave deposition under condition of beam-driven toroidal rotation

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Q. D., E-mail: qgao@swip.ac.cn [Southwestern Institute of Physics, Chengdu 610041 (China); Budny, R. V. [Princeton Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543 (United States)

    2015-03-15

    By using gyro-Landau fluid transport model (GLF23), time-dependent integrated modeling is carried out using TRANSP to explore the dynamic process of internal transport barrier (ITB) formation in the neutral beam heating discharges. When the current profile is controlled by LHCD (lower hybrid current drive), with appropriate neutral beam injection, the nonlinear interplay between the transport determined gradients in the plasma temperature (T{sub i,e}) and toroidal velocity (V{sub ϕ}) and the E×B flow shear (including q-profile) produces transport bifurcations, generating spontaneously a stepwise growing ITB. In the discharge, the constraints imposed by the wave propagation condition causes interplay of the LH driven current distribution with the plasma configuration modification, which constitutes non-linearity in the LH wave deposition. The non-linear effects cause bifurcation in LHCD, generating two distinct quasi-stationary reversed magnetic shear configurations. The change of current profile during the transition period between the two quasi-stationary states results in increase of the E×B shearing flow arising from toroidal rotation. The turbulence transport suppression by sheared E×B flow during the ITB development is analysed, and the temporal evolution of some parameters characterized the plasma confinement is examined. Ample evidence shows that onset of the ITB development is correlated with the enhancement of E×B shearing rate caused by the bifurcation in LHCD. It is suggested that the ITB triggering is associated with the non-linear effects of the LH power deposition.

  8. Outgassing of plasma facing antenna front for lower hybrid wave launcher

    Energy Technology Data Exchange (ETDEWEB)

    Maebara, Sunao E-mail: maebara@felsunl.tokai.jaeri.go.jp; Goniche, Marc; Kazarian, Fabienne; Seki, Masami; Ikeda, Yoshitaka; Imai, Tsuyoshi; Bibet, Philippe; Froissard, Philippe; Rey, Guy

    2000-11-01

    A 3.7 GHz mock-up antenna module using carbon fiber composite (CFC) was fabricated and tested for the development of a heat-resistive front of the lower hybrid current drive (LHCD) antenna. This module has four waveguides and a water cooling channel, the length is 206 mm. The CFC surface was coated with a thin titanium layer and was plated with copper in order to reduce RF losses, to bond rods and septum plates and to assemble them with cooling channel. The RF losses and the outgassing rates of this CFC module at high RF power were measured during long pulses. When the injected power varies between 30 and 100 kW, the RF losses measured by calorimetery, were found to be in the range of 1.0-1.2%. It is found that this experimental value is 2.5-3.0 times higher than the theoretical value of pure copper. Stationary operation of the CFC module with water cooling is performed at the RF power density of 45 MW m{sup -2} during 1000 s. The outgassing rates from the CFC module are in the range of 0.93{approx}1.3x10{sup -6} Pam{sup -3} s{sup -1} m{sup -2} at the module temperature of 120 deg. C, it is low enough for an antenna material. No significant bonding defects occurred during the steady-state operation. It is assessed that a CFC module is an attractive candidate for a heat-resistive front of LHCD antenna.

  9. Influence of gas puff location on the coupling of lower hybrid waves in JET ELMy H-mode plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Ekedahl, A. [CEA, IRFM, France; Petrzilka, V. [Assoc. Euratom-IPP.CR, Czech Republic; Baranov, Y. [EURATOM / UKAEA, UK; Brix, M [UKAEA Fusion, Culham UK; Goniche, M. [CEA, IRFM, France; Jacquet, P. [EURATOM / UKAEA, Abingdon, UK; Kirov, K K [Association EURATOM-CCFE, Abingdon, UK; Klepper, C Christopher [ORNL; Mailloux, J. [EURATOM / UKAEA, UK; Mayoral, M.-L. [EURATOM / UKAEA, UK; Nave, M. F. F. [Association EURATOM/IST, Lisbon, Portugal; Ongena, J. [Laboratory for Plasma Physics-ERM/KMS (LPP-ERM/KMS), Brussels, Belgium

    2012-01-01

    Reliable coupling of the lower hybrid current drive (LHCD) to H-mode plasmas in JET is made feasible through a dedicated gas injection system, located at the outer wall and magnetically connected to the antenna (Pericoli Ridolfini et al 2004 Plasma Phys. Control. Fusion 46 349, Ekedahl et al 2005 Nucl. Fusion 45 351, Ekedahl et al 2009 Plasma Phys. Control. Fusion 51 044001). An experiment was carried out in JET in order to investigate whether a gas injection from the top of the torus, as is foreseen for the main gas injection in ITER, could also provide good coupling of the LH waves if magnetically connected to the antenna. The results show that a top gas injection was not efficient for providing a reliable LHCD power injection, in spite of being magnetically connected and in spite of using almost twice the amount of gas flow compared with the dedicated outer mid-plane gas puffing system. A dedicated gas injection system, set in the outer wall and magnetically connected to the LHCD antenna, is therefore recommended in order to provide the reliable coupling conditions for an LHCD antenna in ITER.

  10. Efficient and broadband optical parametric four wave mixing in chalcogenide-PMMA hybrid microwires

    CERN Document Server

    Ahmad, Raja

    2012-01-01

    The recent development of devices based on novel nonlinear materials like chalcogenides (ChGs), silicon (Si) and other semi-conductors has revolutionized the field of nonlinear photonics [1,2,3]. Among the nonlinear effects observed in these materials, four-wave mixing (FWM) is the process that finds the most applications including wavelength conversion [4], optical regeneration [5,6], optical delay [7], time-domain demultiplexing[8], temporal cloaking[9] and negative refraction[10]. Although FWM has been observed in several media including chalcogenides [11,12,13,14], silicon[15, 16], bismuth [17] and silica [18,19], there is a continued quest for devices that realize efficient and broadband FWM while offering compactness, low-power consumption and compatibility with optical fibers. Here, we demonstrate the fabrication of 10 cm long polymer cladded chalcogenide (As2Se3) microwires to realize FWM-led sub watt threshold (70-370 mW) wavelength conversion with a 12 dB bandwidth as broad as 190 nm, and conversion...

  11. Hybrid multicore/vectorisation technique applied to the elastic wave equation on a staggered grid

    Science.gov (United States)

    Titarenko, Sofya; Hildyard, Mark

    2017-07-01

    In modern physics it has become common to find the solution of a problem by solving numerically a set of PDEs. Whether solving them on a finite difference grid or by a finite element approach, the main calculations are often applied to a stencil structure. In the last decade it has become usual to work with so called big data problems where calculations are very heavy and accelerators and modern architectures are widely used. Although CPU and GPU clusters are often used to solve such problems, parallelisation of any calculation ideally starts from a single processor optimisation. Unfortunately, it is impossible to vectorise a stencil structured loop with high level instructions. In this paper we suggest a new approach to rearranging the data structure which makes it possible to apply high level vectorisation instructions to a stencil loop and which results in significant acceleration. The suggested method allows further acceleration if shared memory APIs are used. We show the effectiveness of the method by applying it to an elastic wave propagation problem on a finite difference grid. We have chosen Intel architecture for the test problem and OpenMP (Open Multi-Processing) since they are extensively used in many applications.

  12. STUDY OF THE CORRELATION BETWEEN POWER DEPOSITION OFTHE LOWER HYBRID WAVES AND THE HARDX-RAY RADIATION ON HT-7 TOKAMAK

    Institute of Scientific and Technical Information of China (English)

    石跃江; 万宝年; 凌必利; 丁伯江

    2001-01-01

    A seven-channel NaI(T1) detector array installed on an HT-7 superconducting tokamak has been used to detect the hard X-ray (Ehv>20 keV) emitted from the plasma. The physical mechanism of the lower hybrid waves propagating and absorbed in the plasma is investigated by the measurement of the hard X-ray radial profile at different discharge parameters.

  13. Numerical Simulation of P-Wave Propagation in Rock Mass with Granular Material-Filled Fractures Using Hybrid Continuum-Discrete Element Method

    Science.gov (United States)

    Gui, Y. L.; Zhao, Z. Y.; Zhou, H. Y.; Wu, W.

    2016-10-01

    In this paper, a cohesive fracture model is applied to model P-wave propagation through fractured rock mass using hybrid continuum-discrete element method, i.e. Universal Distinct Element Code (UDEC). First, a cohesive fracture model together with the background of UDEC is presented. The cohesive fracture model considers progressive failure of rock fracture rather than an abrupt damage through simultaneously taking into account the elastic, plastic and damage mechanisms as well as a modified failure function. Then, a series of laboratory tests from the literature on P-wave propagation through rock mass containing single fracture and two parallel fractures are introduced and the numerical models used to simulate these laboratory tests are described. After that, all the laboratory tests are simulated and presented. The results show that the proposed model, particularly the cohesive fracture model, can capture very well the wave propagation characteristics in rock mass with non-welded and welded fractures with and without filling materials. In the meantime, in order to identify the significance of fracture on wave propagation, filling materials with different particle sizes and the fracture thickness are discussed. Both factors are found to be crucial for wave attenuation. The simulations also show that the frequency of transmission wave is lowered after propagating through fractures. In addition, the developed numerical scheme is applied to two-dimensional wave propagation in the rock mass.

  14. Wave

    DEFF Research Database (Denmark)

    Ibsen, Lars Bo

    2008-01-01

    Estimates for the amount of potential wave energy in the world range from 1-10 TW. The World Energy Council estimates that a potential 2TW of energy is available from the world’s oceans, which is the equivalent of twice the world’s electricity production. Whilst the recoverable resource is many t...

  15. Hybrid integration of synthesized dielectric image waveguides in substrate integrated circuit technology and its millimeter wave applications

    Science.gov (United States)

    Patrovsky, Andreas

    This thesis deals with a novel type of integrated dielectric waveguide which is synthesized on a planar grounded substrate by perforation of the zones adjacent to a guiding channel in the center. The resulting Substrate Integrated Image Guide (SIIG) not only allows for low-loss guidance of electromagnetic waves in a similar way as the standard image guide, but also meets the requirements of low cost and ease of integration. A first objective was the detailed analysis of the propagation properties of fundamental and higher order modes in this waveguide structure, regarding attenuation, dispersion behavior, bandwidth, leakage effects, and the impact of fabrication tolerances. For this purpose, specifically adapted techniques of analysis are presented, since established methods for the conventional image guide can not be applied to the more complex periodic SIIG. Commercial electromagnetic full-wave software is used along with a dual-line approach involving a subsequent extraction of the propagation constant from simulated S-parameters. Alternatively, the solution of the eigenmode problem of a single SIIG unit cell also performs the task. Both techniques are in good agreement and provide accurate results, which is supported by measurements on laser-fabricated prototypes. It is shown that the achievable attenuation is much lower than in the standard integrated technologies and that losses mainly depend on the chosen dielectric material. As a consequence, the SIIG also is an attractive technology for applications beyond the mmW band, i. e. in the terahertz range. Design recommendations for the geometric parameters of the SIIG are discussed and a simplified equivalent model with homogeneous dielectric regions is introduced to speed up the design of passive components. Low-loss transitions between dissimilar waveguide structures are indispensable key components for a hybrid integrated platform. In order to enable the connection of standard measurement equipment in the W

  16. Modeling, Control, and Simulation of Battery Storage Photovoltaic-Wave Energy Hybrid Renewable Power Generation Systems for Island Electrification in Malaysia

    Directory of Open Access Journals (Sweden)

    Nahidul Hoque Samrat

    2014-01-01

    Full Text Available Today, the whole world faces a great challenge to overcome the environmental problems related to global energy production. Most of the islands throughout the world depend on fossil fuel importation with respect to energy production. Recent development and research on green energy sources can assure sustainable power supply for the islands. But unpredictable nature and high dependency on weather conditions are the main limitations of renewable energy sources. To overcome this drawback, different renewable sources and converters need to be integrated with each other. This paper proposes a standalone hybrid photovoltaic- (PV- wave energy conversion system with energy storage. In the proposed hybrid system, control of the bidirectional buck-boost DC-DC converter (BBDC is used to maintain the constant dc-link voltage. It also accumulates the excess hybrid power in the battery bank and supplies this power to the system load during the shortage of hybrid power. A three-phase complex vector control scheme voltage source inverter (VSI is used to control the load side voltage in terms of the frequency and voltage amplitude. Based on the simulation results obtained from Matlab/Simulink, it has been found that the overall hybrid framework is capable of working under the variable weather and load conditions.

  17. Modeling, control, and simulation of battery storage photovoltaic-wave energy hybrid renewable power generation systems for island electrification in Malaysia.

    Science.gov (United States)

    Samrat, Nahidul Hoque; Bin Ahmad, Norhafizan; Choudhury, Imtiaz Ahmed; Bin Taha, Zahari

    2014-01-01

    Today, the whole world faces a great challenge to overcome the environmental problems related to global energy production. Most of the islands throughout the world depend on fossil fuel importation with respect to energy production. Recent development and research on green energy sources can assure sustainable power supply for the islands. But unpredictable nature and high dependency on weather conditions are the main limitations of renewable energy sources. To overcome this drawback, different renewable sources and converters need to be integrated with each other. This paper proposes a standalone hybrid photovoltaic- (PV-) wave energy conversion system with energy storage. In the proposed hybrid system, control of the bidirectional buck-boost DC-DC converter (BBDC) is used to maintain the constant dc-link voltage. It also accumulates the excess hybrid power in the battery bank and supplies this power to the system load during the shortage of hybrid power. A three-phase complex vector control scheme voltage source inverter (VSI) is used to control the load side voltage in terms of the frequency and voltage amplitude. Based on the simulation results obtained from Matlab/Simulink, it has been found that the overall hybrid framework is capable of working under the variable weather and load conditions.

  18. Ploidia e fertilidade de pólen em progênies de citros Ploidy and pollen fertility in citrus hybrids

    Directory of Open Access Journals (Sweden)

    Eduardo Cesar Brugnara

    2008-01-01

    Full Text Available Este trabalho foi desenvolvido para estimar a fertilidade do pólen e determinar o nível de ploidia em progênies dos cruzamentos da tangerineira 'Montenegrina' (C. deliciosa Ten. com a tangerineira 'King' (C. nobilis Lour. e com a laranjeira 'Caipira' (C. sinensis (L. Osb.. As plantas, de pés-francos e com idade entre 11 e 12 anos, são mantidas na Estação Experimental Agronômica da Universidade Federal do Rio Grande do Sul, em Eldorado do Sul. Avaliaram-se o nível de ploidia, através da contagem dos cromossomos em células em meiose, e a fertilidade do pólen, por coloração do pólen com carmim propiônico, em 2005 e 2006. Todos os híbridos avaliados são diplóides e a fertilidade de pólen variou de zero a 98%. C27 - híbrido de 'Montenegrina' x 'Caipira' - revelou-se praticamente estéril, e a fertilidade de C21, do mesmo cruzamento, é de 10%. A menor fertilidade observada no cruzamento da 'Montenegrina' x 'King' foi de 42%.This work was performed to estimate pollen fertility and determinate the ploidy level of 11 to 12 years old progenies of crosses of 'Montenegrina' mandarin (Citrus deliciosa Ten. with 'King' mandarin (C. nobilis Lour. and with 'Caipira' sweet orange (C. sinensis (L. Osb. maintained at Estação Experimental Agronômica of UFRGS, in Eldorado do Sul, Brazil. The ploidy level was determined by chromosome countings in meiosis cells and pollen fertility evaluated by staining pollen grains with propionic carmine. All evaluated hybrids are diploid and pollen fertility varied from zero to 98%. C27, a hybrid 'Montenegrina' x 'Caipira', was found is sterile, and C21, from the same cross, showed 10 % fertility. The lowest observed fertility in the progeny 'Montenegrina' x 'King' was 42 %.

  19. Application of the Aero-Hydro-Elastic Model, HAWC2-WAMIT, to Offshore Data from Floating Power Plants Hybrid Wind- and Wave-Energy Test Platform, P37

    DEFF Research Database (Denmark)

    Bellew, Sarah; Yde, Anders; Verelst, David Robert

    2014-01-01

    numerical models, which can combine the aerodynamic, hydrodynamic, structural exibility and mooring components. Very little oshore data exists, however, in order to validate these numerical models. Floating Power Plant are the developers of a oating, hybrid wind- and wave-energy device. The device uses...... full-scale prototype, the P80, which has a width of 80 m. As part of the development, Floating Power Plant have completed 4 oshore test-phases (totalling over 2 years oshore operation) on a 37 m wide scaled test device, the P37. This paper focuses on the comparison of one of the leading numerical...... the pitching wave energy devices, not only to increase and smooth the power output from the platform, but also to take the energy from the waves in a controlled manner, resulting in a stable platform for the wind turbine and a safe harbour for O&M. They are currently developing the nal design for their rst...

  20. Travelling-wave ion mobility mass spectrometry and negative ion fragmentation of hybrid and complex N-glycans.

    Science.gov (United States)

    Harvey, David J; Scarff, Charlotte A; Edgeworth, Matthew; Pagel, Kevin; Thalassinos, Konstantinos; Struwe, Weston B; Crispin, Max; Scrivens, James H

    2016-11-01

    Nitrogen collisional cross sections (CCSs) of hybrid and complex glycans released from the glycoproteins IgG, gp120 (from human immunodeficiency virus), ovalbumin, α1-acid glycoprotein and thyroglobulin were measured with a travelling-wave ion mobility mass spectrometer using dextran as the calibrant. The utility of this instrument for isomer separation was also investigated. Some isomers, such as Man3 GlcNAc3 from chicken ovalbumin and Man3 GlcNAc3 Fuc1 from thyroglobulin could be partially resolved and identified by their negative ion fragmentation spectra obtained by collision-induced decomposition (CID). Several other larger glycans, however, although existing as isomers, produced only asymmetric rather than separated arrival time distributions (ATDs). Nevertheless, in these cases, isomers could often be detected by plotting extracted fragment ATDs of diagnostic fragment ions from the negative ion CID spectra obtained in the transfer cell of the Waters Synapt mass spectrometer. Coincidence in the drift times of all fragment ions with an asymmetric ATD profile in this work, and in the related earlier paper on high-mannose glycans, usually suggested that separations were because of conformers or anomers, whereas symmetrical ATDs of fragments showing differences in drift times indicated isomer separation. Although some significant differences in CCSs were found for the smaller isomeric glycans, the differences found for the larger compounds were usually too small to be analytically useful. Possible correlations between CCSs and structural types were also investigated, and it was found that complex glycans tended to have slightly smaller CCSs than high-mannose glycans of comparable molecular weight. In addition, biantennary glycans containing a core fucose and/or a bisecting GlcNAc residue fell on different mobility-m/z trend lines to those glycans not so substituted with both of these substituents contributing to larger CCSs. Copyright © 2016 John Wiley & Sons

  1. Thermoelectric-pyroelectric hybrid energy generation from thermopower waves in core-shell structured carbon nanotube-PZT nanocomposites

    Science.gov (United States)

    Yeo, Taehan; Hwang, Hayoung; Shin, Dongjoon; Seo, Byungseok; Choi, Wonjoon

    2017-02-01

    There is an urgent need to develop a suitable energy source owing to the rapid development of various innovative devices using micro-nanotechnology. The thermopower wave (TW), which produces a high specific power during the combustion of solid fuel inside micro-nanostructure materials, is a unique energy source for unusual platforms that cannot use conventional energy sources. Here, we report on the significant enhancement of hybrid energy generation of pyroelectrics and thermoelectrics from TWs in carbon nanotube (CNT)-PZT (lead zirconate titanate, P(Z0.5-T0.5)) composites for the first time. Conventional TWs use only charge carrier transport driven by the temperature gradient along the core materials to produce voltage. In this study, a core-shell structure of CNTs-PZTs was prepared to utilize both the temperature gradient along the core material (thermoelectrics) and the dynamic change in the temperature of the shell structure (pyroelectrics) induced by TWs. The dual mechanism of energy generation in CNT-PZT composites amplified the average peak and duration of the voltage up to 403 mV and 612 ms, respectively, by a factor of 2 and 60 times those for the composites without a PZT layer. Furthermore, dynamic voltage measurements and structural analysis in repetitive TWs confirmed that CNT-PZT composites maintain the original performance in multiple TWs, which improves the reusability of materials. The advanced TWs obtained by the application of a PZT layer as a pyroelectric material contributes to the extension of the usable energy portion as well as the development of TW-based operating devices.

  2. Multi-hybrid method for investigation of EM scattering from inhomogeneous object above a dielectric rough surface

    Science.gov (United States)

    Li, Jie; Guo, LiXin; He, Qiong; Wei, Bing

    2012-10-01

    An iterative strategy combining Kirchhoff approximation^(KA) with the hybrid finite element-boundary integral (FE-BI) method is presented in this paper to study the interactions between the inhomogeneous object and the underlying rough surface. KA is applied to study scattering from underlying rough surfaces, whereas FE-BI deals with scattering from the above target. Both two methods use updated excitation sources. Huygens equivalence principle and an iterative strategy are employed to consider the multi-scattering effects. This hybrid FE-BI-KA scheme is an improved and generalized version of previous hybrid Kirchhoff approximation-method of moments (KA-MoM). This newly presented hybrid method has the following advantages: (1) the feasibility of modeling multi-scale scattering problems (large scale underlying surface and small scale target); (2) low memory requirement as in hybrid KA-MoM; (3) the ability to deal with scattering from inhomogeneous (including coated or layered) scatterers above rough surfaces. The numerical results are given to evaluate the accuracy of the multi-hybrid technique; the computing time and memory requirements consumed in specific numerical simulation of FE-BI-KA are compared with those of MoM. The convergence performance is analyzed by studying the iteration number variation caused by related parameters. Then bistatic scattering from inhomogeneous object of different configurations above dielectric Gaussian rough surface is calculated and the influences of dielectric compositions and surface roughness on the scattering pattern are discussed.

  3. Application of P-wave Hybrid Theory to the Scattering of Electrons from He+ and Resonances in He and H ion

    Science.gov (United States)

    Bhatia, A. K.

    2012-01-01

    The P-wave hybrid theory of electron-hydrogen elastic scattering [Phys. Rev. A 85, 052708 (2012)] is applied to the P-wave scattering from He ion. In this method, both short-range and long-range correlations are included in the Schroedinger equation at the same time, by using a combination of a modified method of polarized orbitals and the optical potential formalism. The short-correlation functions are of Hylleraas type. It is found that the phase shifts are not significantly affected by the modification of the target function by a method similar to the method of polarized orbitals and they are close to the phase shifts calculated earlier by Bhatia [Phys. Rev. A 69, 032714 (2004)]. This indicates that the correlation function is general enough to include the target distortion (polarization) in the presence of the incident electron. The important fact is that in the present calculation, to obtain similar results only a 20-term correlation function is needed in the wave function compared to the 220- term wave function required in the above-mentioned calculation. Results for the phase shifts, obtained in the present hybrid formalism, are rigorous lower bounds to the exact phase shifts. The lowest P-wave resonances in He atom and hydrogen ion have been calculated and compared with the results obtained using the Feshbach projection operator formalism [Phys. Rev. A, 11, 2018 (1975)]. It is concluded that accurate resonance parameters can be obtained by the present method, which has the advantage of including corrections due to neighboring resonances, bound states and the continuum in which these resonance are embedded.

  4. Avaliação de cultivares e hibridos de bananeira em lavras, MG Banana hybrids and cultivar evaluation in lavras-MG

    Directory of Open Access Journals (Sweden)

    Lair Victor Pereira

    2003-02-01

    Full Text Available Avaliaram-se os genótipos de bananeira Nam, Pioneira, Caipira, Prata Anã, Grande Naine, SH36-40, FHIA 18, FHIA 01 e PV 03-44, em condições de sequeiro na região sul de Minas Gerais, com o objetivo de identificar os mais produtivos e com melhor adaptação edafoclimática, em comparação com as cultivares Prata e Prata Anã, tradicionalmente cultivadas nessa região. O ensaio foi conduzido na Fazenda Experimental da EPAMIG, em Lavras, no período de 1997 a 1999. Cada genótipo foi plantado em blocos de 50 plantas, no espaçamento 3,0 x 3,0 m, sendo a parcela útil as 24 plantas centrais e uma por repetição. O híbrido SH36-40 foi superior aos demais em peso médio dos cachos (16,56 kg, frutos (171,00 g, diâmetro (4,21 cm e comprimento dos frutos (17,64 cm nos três primeiros ciclos. Isso corresponde a um rendimento de 18,5 t/ha, cerca de duas vezes maior que a produção das cultivares Prata Anã, Pioneira, Nam, Caipira e três vezes maior que a do híbrido PV 03-44. O híbrido SH 36-40 apresentou, ainda, porte médio de 2,75 m, ciclo em torno de 17,5 meses e o menor período da emissão à colheita do cacho, inferior a 4,83 meses para as plantas-mãe, filha e neta. Esse híbrido apresentou também um menor e mais tardio perfilhamento. Os híbridos SH 36-40 e FHIA 01 apresentaram os maiores incrementos nos pesos dos cachos e dos frutos do primeiro para o terceiro ciclo. As cultivares Caipira, Prata Anã, Pioneira e Nam produziram cachos com peso médio inferior a 9,0 kg e o híbrido PV0344, inferior a 6,0 kg. A cv. Caipira foi a mais tardia, com um ciclo em torno de 22 meses e a Prata Anã e Pioneira, as mais precoces, com cerca de 16,6 meses no primeiro ciclo e 15,5 no segundo e terceiro ciclos.The banana genotypes Nam, Caipira, Pioneira, Prata anã, Grande Naine, FHIA 01, FHIA 18, SH 36-44, and PV 03-44 were evaluated from 1997 to 1999. The objective was to identify the most productive and most adaptated genotype compared to the

  5. Elastic wave band gaps tuned by configuring radii of rods in two-dimensional phononic crystals with a hybrid square-like lattice

    Science.gov (United States)

    Liu, Rongqiang; Zhao, Haojiang; Zhang, Yingying; Guo, Honghwei; Deng, Zongquan

    2015-12-01

    The plane wave expansion (PWE) method is used to calculate the band gaps of two-dimensional (2D) phononic crystals (PCs) with a hybrid square-like (HSL) lattice. Band structures of both XY-mode and Z-mode are calculated. Numerical results show that the band gaps between any two bands could be maximized by altering the radius ratio of the inclusions at different positions. By comparing with square lattice and bathroom lattice, the HSL lattice is more efficient in creating larger gaps.

  6. Analysis on the Radiation Property of the Bounded Modes of Periodic Leaky-Wave Structure with Finite-Length Using a Hybrid Method.

    Science.gov (United States)

    Li, Zheng; Wang, Junhong; Duan, Jianjie; Zhang, Zhan; Chen, Meie

    2016-03-18

    In this paper the radiation property of the one-dimensional periodic leaky-wave structure is analysed using a new hybrid method, which involves the mode expansion method for expanding the periodic aperture field in terms of spatial harmonics and the method of effective radiation sections for transforming the expanded fields into far fields. Using this method, the radiation of each spatial harmonic can be achieved, and the contributions of the harmonics (especially the bounded modes) to the total radiation of the periodic leaky-wave structure can be calculated. The main findings in this paper demonstrate that the bounded modes in a finite length structure have obvious contribution to the far-field radiation, which was considered to be non-radiative and always ignored in the conventional researches.

  7. The Realization of Low Loop Voltage Start-up of HT-7 Tokamak Discharge with the Assistance of Lower Hybrid Wave

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Low voltage start-up was realized in HT-7 discharges under the assistance of lower hybrid (LH) waves. The use of a strong LH wave, which can change its N// spectrum in a large range of several milliseconds, made the loop voltage for start-up reduce from around 20 V to less than 5 V. It means that the electric field for HT-7 start-up decreases from 2.5~3 V/m to 0.6 V/m.Some physical phenomena such as the consumption of magnetic flux in start-up phase and the radiation from the initial plasma were observed in this kind of low voltage start-up discharges.

  8. Proton, Helium and Minor Ion Interactions with Circularly Polarized Alfven and Ion-cyclotron waves in the Expanding Solar Wind: Hybrid Simulations

    Science.gov (United States)

    Velli, M.; Liewer, P. C.; Goldstein, B. E.

    2000-05-01

    We present simulations of parallel propagating Alfvén waves in the accelerating solar wind and their interactions with protons, alpha particles, and minor ions using an expanding box hybrid code (Liewer et al., 1999). In this model, the average solar wind flow speed is a given external function, and the simulation domain follows a plasma parcel as it expands both in the radial and transverse directions accordingly: the decrease of Alfvén speed and density with distance from the Sun are taken into account self-consistently. It is therefore possible to carry out a detailed study of frequency drifting and the coming into resonance with the waves at different radial locations of particles with differing charge to mass ratios. Simulations of monochromatic waves as well as waves with well-developed spectra are presented for plasmas with one, two and three ion species. We observe preferential heating and acceleration of protons and minor ions. Under some conditions, we obtain the scaling observed in coronal hole solar wind: the heavy ion temperature is proportional to its mass (Liewer et al., 2000). A comparison with predictions from models based on such quasi-linear or linear analyses will also be presented. P. C. Liewer, M. Velli and B. E. Goldstein, in Solar Wind Nine, S. Habbal, R. Esser, J. V. Hollweg, P. A. Isenberg, eds., (AIP Conference Proceedings 471, 1999) 449. P. C. Liewer, M. Velli, and B. E. Goldstein, in Proc. ACE 2000 Conference (2000) to be published.

  9. Reprodução de Meloidogyne spp. em porta-enxertos e híbridos de pepino Reproduction of Meloidogyne spp. in rootstocks and cucumber hybrids

    Directory of Open Access Journals (Sweden)

    Silvia Renata S Wilcken

    2010-03-01

    Full Text Available A enxertia é uma técnica alternativa frequentemente recomendada para a cultura do pepino em áreas infestadas com nematóides das galhas. O presente trabalho teve como objetivo determinar o fator de reprodução de Meloidogyne javanica e de Meloidogyne incognita raça 2 em seis porta-enxertos para pepino (abóbora 'Menina Brasileira', moranga 'Exposição', 'Shelper', 'Tetsukabuto', 'B8-A Tetsukabuto' e 'Excite Ikki' e quatro híbridos de pepino (Cucumis sativus tipo japonês ('Yoshinari', 'Kouki', 'Taisho' e 'Tsuyataro'. Foram conduzidos dois experimentos em casa-de-vegetação, um com cada espécie do nematóide, sendo cada parcela constituída de uma planta mantida em vaso contendo 2 litros de solo autoclavado. Nove dias após transplante, cada planta foi inoculada com 5.000 ovos e juvenis de segundo estádio (população inicial - Pi de M. javanica ou M. incognita raça 2. Tomateiros 'Rutgers' foram utilizados como padrão de viabilidade do inóculo, em ambos os experimentos. O delineamento experimental foi inteiramente casualizado com cinco repetições por tratamento. Sessenta dias após a inoculação, cada planta foi avaliada, quanto ao peso fresco da raiz, número total de nematóides presentes no solo e na raiz (população final - Pf, número de nematóides/g de raiz e fator de reprodução de ambas as espécies de Meloidogyne (FR=Pf/Pi. Todos os porta-enxertos e híbridos de pepino testados apresentaram fatores de reprodução superiores a um, proporcionando a multiplicação de M. javanica e de M. incognita raça 2, porém, os valores nos híbridos de pepino foram superiores aos dos porta-enxertos.Grafting is an alternative technique often recommended for the cucumber crop in root-knot nematodes infested areas. This study aimed to determine the reproduction factor of Meloidogyne javanica and M. incognita race 2 on six rootstocks for cucumber (squash 'Menina Brasileira, pumpkim 'Exposição', 'Shelper', 'Tetsukabuto', 'B8-A

  10. Estimativa do filocrono em milho para híbridos com diferentes ciclos de desenvolvimento vegetativo Estimating the phyllocron in maize hybrids with different cycles of vegetative development

    Directory of Open Access Journals (Sweden)

    Juliano Dalcin Martins

    2012-05-01

    Full Text Available O filocrono é definido como o tempo térmico necessário para o aparecimento de folhas sucessivas na haste principal de uma planta. Através do filocrono, pode-se calcular a duração do período vegetativo e, portanto, a época de florescimento em função da temperatura do ar. O presente trabalho teve por objetivo determinar o filocrono de diferentes híbridos de milho. Foram conduzidos três experimentos a campo, nos anos agrícolas de 2007/08, 2008/09 e 2009/2010. O delineamento experimental foi o de blocos ao acaso com três repetições. Os tratamentos constituíram-se de 18, 22 e 24 híbridos de milho, nos anos agrícolas de 2007/08, 2008/09 e 2009/2010, respectivamente. O filocrono foi estimado pelo inverso do coeficiente angular da regressão linear entre o número de folhas e a soma térmica acumulada a partir de emergência (temperatura base = 10°C. O filocrono calculado variou de 44,3 a 34,4°C dia-1 folha-1 entre os híbridos avaliados, estando o valor de filocrono dos híbridos diretamente relacionados com a precocidade do período vegetativo.The phyllochron is defined as the thermal time needed for the appearance of successive leaves on the plant main stem. Through the phyllochron it is possible to calculate the length of the growing period and thus the flowering period based on the air temperature. This study aimed to determine the phyllochron from different maize hybrids. Three field experiments were carried out during the agricultural years of 2007/08, 2008/09 and 2009/2010. The experimental design was one of randomized blocks with three repetitions. The treatments consisted of 18, 22 and 24 maize hybrid during the three agricultural years of 2007/08, 2008/09 and 2009/2010, respectively. The phyllochron was estimated by the inverse of the angular coefficient of the linear regression between the number of leaves and the accumulated thermal sum from emergence on (base temperature = 10°C. The calculated phyllochron varied from

  11. One-dimensional full wave treatment of mode conversion process at the ion-ion hybrid resonance in a bounded tokamak plasma

    Energy Technology Data Exchange (ETDEWEB)

    Monakhov, I.; Becoulet, A.; Fraboulet, D.; NGuyen, F

    1998-09-01

    A consistent picture of the mode conversion (MC) process at the ion-ion hybrid resonance in a bounded plasma of a tokamak is discussed, which clarifies the role of the global fast wave interference and cavity effects in the determination of the MC efficiency. This picture is supported by simulations with one-dimensional full wave kinetic code `VICE`. The concept of the `global resonator`, formed by the R = n{sup 2}{sub ||} boundary cutoffs [B. Saoutic et al., Phys. Rev. Lett. 76, 1647 (1996)], is justified, as well as the importance of a proper tunneling factor choice {eta}{sub cr} = 0.22 [A. K. Ram et al., Phys. Plasmas 3, 1976 (1996)]. The MC scheme behavior appears to be very sensitive to the MC layer position relative to the global wave field pattern, i.e. to the local value of `poloidal` electric field at the resonance. Optimal MC regimes are found to be attainable without requirement of a particular parallel wavenumber choice. (author) 40 refs.

  12. Hybrid genetic algorithm tuned support vector machine regression for wave transmission prediction of horizontally interlaced multilayer moored floating pipe breakwater

    Digital Repository Service at National Institute of Oceanography (India)

    Patil, S.G.; Mandal, S.; Hegde, A.V.; Muruganandam, A.

    of HIMMFPB using regular wave fl ume at Marine Structure Laboratory, National Institute of Technology, Surathkal, India. The results are compared with artifi cial neural network (ANN) model in terms of Correlation Coeffi cient, Root Mean Square Error...

  13. A Mathematical Approach to Hybridization

    Science.gov (United States)

    Matthews, P. S. C.; Thompson, J. J.

    1975-01-01

    Presents an approach to hybridization which exploits the similarities between the algebra of wave functions and vectors. This method will account satisfactorily for the number of orbitals formed when applied to hybrids involving the s and p orbitals. (GS)

  14. Expression of Selected <em>Ginkgo em>>biloba em>Heat Shock Protein Genes After Cold Treatment Could Be Induced by Other Abiotic Stress

    Directory of Open Access Journals (Sweden)

    Feng Xu

    2012-05-01

    Full Text Available Heat shock proteins (HSPs play various stress-protective roles in plants. In this study, three <em>HSP> genes were isolated from a suppression subtractive hybridization (SSH cDNA library of <em>Ginkgo bilobaem> leaves treated with cold stress. Based on the molecular weight, the three genes were designated <em>GbHSP16.8em>, <em>GbHSP17em> and <em>GbHSP70em>. The full length of the three genes were predicted to encode three polypeptide chains containing 149 amino acids (Aa, 152 Aa, and 657 Aa, and their corresponding molecular weights were predicted as follows: 16.67 kDa, 17.39 kDa, and 71.81 kDa respectively. The three genes exhibited distinctive expression patterns in different organs or development stages. <em>GbHSP16.8em> and <em>GbHSP70em> showed high expression levels in leaves and a low level in gynoecia, <em>GbHSP17em> showed a higher transcription in stamens and lower level in fruit. This result indicates that <em>GbHSP16.8em> and <em>GbHSP70 em>may play important roles in <em>Ginkgo> leaf development and photosynthesis, and <em>GbHSP17em> may play a positive role in pollen maturation. All three <em>GbHSPs> were up-regulated under cold stress, whereas extreme heat stress only caused up-regulation of <em>GbHSP70em>, UV-B treatment resulted in up-regulation of <em>GbHSP16.8em> and <em>GbHSP17em>, wounding treatment resulted in up-regulation of <em>GbHSP16.8em> and <em>GbHSP70em>, and abscisic acid (ABA treatment caused up-regulation of <em>GbHSP70em> primarily.

  15. New high-order, semi-implicit Hybridized Discontinuous Galerkin - Spectral Element Method (HDG-SEM) for simulation of complex wave propagation involving coupling between seismic, hydro-acoustic and infrasonic waves: numerical analysis and case studies.

    Science.gov (United States)

    Terrana, S.; Vilotte, J. P.; Guillot, L.

    2015-12-01

    New seismological monitoring networks combine broadband seismic receivers, hydrophones and micro-barometers antenna, providing complementary observation of source-radiated waves. Exploiting these observations requires accurate and multi-media - elastic, hydro-acoustic, infrasound - wave simulation methods, in order to improve our physical understanding of energy exchanges at material interfaces.We present here a new development of a high-order Hybridized Discontinuous Galerkin (HDG) method, for the simulation of coupled seismic and acoustic wave propagation, within a unified framework ([1],[2]) allowing for continuous and discontinuous Spectral Element Methods (SEM) to be used in the same simulation, with conforming and non-conforming meshes. The HDG-SEM approximation leads to differential - algebraic equations, which can be solved implicitly using energy-preserving time-schemes.The proposed HDG-SEM is computationally attractive, when compared with classical Discontinuous Galerkin methods, involving only the approximation of the single-valued traces of the velocity field along the element interfaces as globally coupled unknowns. The formulation is based on a variational approximation of the physical fluxes, which are shown to be the explicit solution of an exact Riemann problem at each element boundaries. This leads to a highly parallel and efficient unstructured and high-order accurate method, which can be space-and-time adaptive.A numerical study of the accuracy and convergence of the HDG-SEM is performed through a number of case studies involving elastic-acoustic (infrasound) coupling with geometries of increasing complexity. Finally, the performance of the method is illustrated through realistic case studies involving ground wave propagation associated to topography effects.In conclusion, we outline some on-going extensions of the method.References:[1] Cockburn, B., Gopalakrishnan, J., Lazarov, R., Unified hybridization of discontinuous Galerkin, mixed and

  16. Current generation by helicons and lower hybrid waves in modern tokamaks and reactors ITER and DEMO. Scenarios, modeling and antennae

    Energy Technology Data Exchange (ETDEWEB)

    Vdovin, V. L., E-mail: vdov@nfi.kiae.ru [National Research Centre ' Kurchatov Institute,' (Russian Federation)

    2013-02-15

    The innovative concept and 3D full-wave code modeling the off-axis current drive by radio-frequency (RF) waves in large-scale tokamaks, ITER and DEMO, for steady-state operation with high efficiency is proposed. The scheme uses the helicon radiation (fast magnetosonic waves at high (20-40) ion cyclotron frequency harmonics) at frequencies of 500-700 MHz propagating in the outer regions of the plasmas with a rotational transform. It is expected that the current generated by helicons, in conjunction with the bootstrap current, ensure the maintenance of a given value of the total current in the stability margin q(0) {>=} 2 and q(a) {>=} 4, and will help to have regimes with a negative magnetic shear and internal transport barrier to ensure stability at high normalized plasma pressure {beta}{sub N} > 3 (the so-called advanced scenarios) of interest for the commercial reactor. Modeling with full-wave three-dimensional codes PSTELION and STELEC showed flexible control of the current profile in the reactor plasmas of ITER and DEMO, using multiple frequencies, the positions of the antennae and toroidal wave slow down. Also presented are the results of simulations of current generation by helicons in the DIII-D, T-15MD, and JT-60AS tokamaks. Commercially available continuous-wave klystrons of the MW/tube range are promising for commercial stationary fusion reactors. The compact antennae of the waveguide type are proposed, and an example of a possible RF system for today's tokamaks is given. The advantages of the scheme (partially tested at lower frequencies in tokamaks) are a significant decline in the role of parametric instabilities in the plasma periphery, the use of electrically strong resonator-waveguide type antennae, and substantially greater antenna-plasma coupling.

  17. Current generation by helicons and lower hybrid waves in modern tokamaks and reactors ITER and DEMO. Scenarios, modeling and antennae

    Science.gov (United States)

    Vdovin, V. L.

    2013-02-01

    The innovative concept and 3D full-wave code modeling the off-axis current drive by radio-frequency (RF) waves in large-scale tokamaks, ITER and DEMO, for steady-state operation with high efficiency is proposed. The scheme uses the helicon radiation (fast magnetosonic waves at high (20-40) ion cyclotron frequency harmonics) at frequencies of 500-700 MHz propagating in the outer regions of the plasmas with a rotational transform. It is expected that the current generated by helicons, in conjunction with the bootstrap current, ensure the maintenance of a given value of the total current in the stability margin q(0) ≥ 2 and q( a) ≥ 4, and will help to have regimes with a negative magnetic shear and internal transport barrier to ensure stability at high normalized plasma pressure β N > 3 (the so-called advanced scenarios) of interest for the commercial reactor. Modeling with full-wave three-dimensional codes PSTELION and STELEC showed flexible control of the current profile in the reactor plasmas of ITER and DEMO, using multiple frequencies, the positions of the antennae and toroidal wave slow down. Also presented are the results of simulations of current generation by helicons in the DIII-D, T-15MD, and JT-60AS tokamaks. Commercially available continuous-wave klystrons of the MW/tube range are promising for commercial stationary fusion reactors. The compact antennae of the waveguide type are proposed, and an example of a possible RF system for today's tokamaks is given. The advantages of the scheme (partially tested at lower frequencies in tokamaks) are a significant decline in the role of parametric instabilities in the plasma periphery, the use of electrically strong resonator-waveguide type antennae, and substantially greater antenna-plasma coupling.

  18. Charge Density Wave and Crystal Structure of KxWO3 (x=0.20 and 0.22) Prepared by Hybrid Microwave Method

    Science.gov (United States)

    Chen, Runze; Gao, Chaojun; Bu, Kun; Hao, Xiaoyu; Wang, Zichen; Wen, Lianjun; Guo, Juan; Chao, Mingju; Liang, Erjun; Yang, Lihong; Dong, Cheng

    2017-02-01

    Potassium tungsten bronzes KxWO3 (x=0.20 and 0.22) with the coexistence of charge density wave (CDW) and superconductivity (SC) were prepared from K2WO4, WO3 and W powders using a hybrid microwave method. The structure refinement confirmed that all samples had a pure hexagonal phase with the space group of P63 /mcm. The distortion degree of W-O octahedron declines with x and is independent of synthesis condition for the same x (=0.20). The CDW transition is studied as a function of residual resistivity ratio. By increasing the crystallinity of sample, this transition can be suppressed, which is probably attributed to the interaction between CDW and defects in crystallites. The CDW transition temperature increases with x, which may be related to the decline of the distortion degree of W-O octahedron. The competition between CDW and SC is observed according to the resistivity and magnetization measurements.

  19. Four-wave mixing signal enhancement and optical bistability of a hybrid metal nanoparticle-quantum dot molecule in a nanomechanical resonator.

    Science.gov (United States)

    Li, Jian-Bo; Liang, Shan; Xiao, Si; He, Meng-Dong; Kim, Nam-Chol; Chen, Li-Qun; Wu, Gui-Hong; Peng, Yu-Xiang; Luo, Xiao-Yu; Guo, Ze-Ping

    2016-02-08

    We investigate theoretically four-wave mixing (FWM) response and optical bistability (OB) in a hybrid nanosystem composed of a metal nanoparticle (MNP) and a semiconductor quantum dot (SQD) coupled to a nanomechanical resonator (NR). It is shown that the FWM signal is enhanced by more than three orders of magnitude as compared to that of the system without exciton-phonon interaction, and the FWM signal can also be suppressed significantly and broadened due to the exciton-plasmon interaction. As the MNP couples strongly with the SQD, the bistable FWM response can be achieved by adjusting the SQD-MNP distance and the pumping intensity. For a given pumping constant and a fixed SQD-MNP distance, the enhanced exciton-phonon interaction can promote the occurrence of bistability. Our findings not only present a feasible way to detect the spacing between two nanoparticles, but also hold promise for developing quantum switches and nanoscale rulers.

  20. Fiber-wireless integrated mobile backhaul network based on a hybrid millimeter-wave and free-space-optics architecture with an adaptive diversity combining technique.

    Science.gov (United States)

    Zhang, Junwen; Wang, Jing; Xu, Yuming; Xu, Mu; Lu, Feng; Cheng, Lin; Yu, Jianjun; Chang, Gee-Kung

    2016-05-01

    We propose and experimentally demonstrate a novel fiber-wireless integrated mobile backhaul network based on a hybrid millimeter-wave (MMW) and free-space-optics (FSO) architecture using an adaptive combining technique. Both 60 GHz MMW and FSO links are demonstrated and fully integrated with optical fibers in a scalable and cost-effective backhaul system setup. Joint signal processing with an adaptive diversity combining technique (ADCT) is utilized at the receiver side based on a maximum ratio combining algorithm. Mobile backhaul transportation of 4-Gb/s 16 quadrature amplitude modulation frequency-division multiplexing (QAM-OFDM) data is experimentally demonstrated and tested under various weather conditions synthesized in the lab. Performance improvement in terms of reduced error vector magnitude (EVM) and enhanced link reliability are validated under fog, rain, and turbulence conditions.

  1. Plasma current start-up experiments using outboard- and top-launch lower hybrid wave on the TST-2 spherical tokamak

    Science.gov (United States)

    Shinya, T.; Takase, Y.; Yajima, S.; Moeller, C.; Yamazaki, H.; Tsujii, N.; Yoshida, Y.; Ejiri, A.; Togashi, H.; Toida, K.; Furui, H.; Homma, H.; Nakamura, K.; Roidl, B.; Sonehara, M.; Takahashi, W.; Takeuchi, T.

    2017-03-01

    Non-inductive plasma current start-up experiments were performed using the lower hybrid wave (LHW) on the TST-2 spherical tokamak. The density limit, observed in previous experiments using the outboard-launch antenna, disappeared after changing the plasma condition in the scrape-off layer, and the plasma current reached about 20 kA. In order to improve the LHW power deposition in the plasma core through an up-shift of the parallel wavenumber during the first pass through the plasma, a new top-launch antenna was designed, fabricated and installed. The plasma current ramp-up to 12 kA was achieved using the top-launch antenna alone in a preliminary experiment. Ray-tracing calculations using the measured plasma parameters showed a large up-shift during the first pass, satisfying the strong electron Landau damping condition in the plasma core.

  2. HT一7低杂波天线精确定位系统%The Accurate Positioning System of the Antenna in HT- 7 Lower Hybrid Wave

    Institute of Scientific and Technical Information of China (English)

    林建安; 匡光力; 刘岳修

    2001-01-01

    In the paper the composition and working principle of the accurate positioning system of the antenna in HT- 7 lower hybrid wave is introduced and the principle and process of software and hardware' s design is described. The principle and method for making periodic digital signals by using high- speed output ports of single- chip computer is analyzed in detail and detailed frame- graphs of related programs are given.%文中主要介绍了HT一7低杂波天线精确定位系统的组成及工作原理,描述了软硬件设计的原理和过程,详细地分析了单片机高速输出端口生成周期性数字信号的原理和方法,并给出了相关程序的详细框图。

  3. Stability of combining ability effects in maize hybrids Estabilidade dos efeitos da capacidade de combinação em híbridos de milho

    Directory of Open Access Journals (Sweden)

    Juarez Campolina Machado

    2009-08-01

    Full Text Available General and specific combining ability effects are important indicators in a maize (Zea mays L. breeding program aiming hybrid development. The objectives of the present study were to estimate the general (GCA and specific combining abilities (SCA effects of commercial maize hybrids using a complete diallel scheme and to assess the stabilities of these estimates. Fifty-five entries were assessed; ten commercial single-crosses and all possible double-crosses. The experiments were carried out in 12 environments in the 2005/06 growing season. A randomized complete block design was used with three replications per environment. Ear yield was evaluated, corrected to 13% of moisture content. The combined diallel analysis involving all environments was performed and the stability of general and specific combining ability effects was investigated. The underlying nonparametric statistics evaluated the contribution of each effect to the genotype by environment interaction. Non-additive effects were more important for this set of hybrids than the additive effects. It was possible to select parents with high stability for combining ability and with high GCA.Os efeitos da capacidade geral (CGC e específica de combinação (CEC são indicadores importantes em um programa de melhoramento milho (Zea mays L. visando a obtenção de híbridos. Os objetivos do presente trabalho foram estimar os efeitos da capacidade geral e específica de combinação de híbridos comerciais de milho e avaliar a estabilidade das estimativas desses parâmetros. Para isso foram avaliados 55 tratamentos, sendo dez híbridos simples comerciais e os 45 híbridos duplos possíveis. Os experimentos foram conduzidos em 12 ambientes no ano agrícola de 2005/06. O delineamento empregado foi o de blocos casualizados com três repetições por ambiente, e o caráter avaliado foi o peso de espigas corrigido para 13% de umidade. Procedeu-se à análise dialélica conjunta envolvendo todos os

  4. Novel Raman Parametric Hybrid L-Band Amplifier with Four-Wave Mixing Suppressed Pump for Terabits Dense Wavelength Division Multiplexed Systems

    Directory of Open Access Journals (Sweden)

    Gaganpreet Kaur

    2016-01-01

    Full Text Available We demonstrate improved performance of parametric amplifier cascaded with Raman amplifier for gain of 54.79 dB. We report amplification of L-band using 100 × 10 Gbps Dense Wavelength Division Multiplexed (DWDM system with 25 GHz channel spacing. The gain achieved is the highest reported so far with gain flatness of 3.38 dB without using any gain flattening technique. Hybrid modulated parametric pump is used for suppressing four-wave mixing (FWM around pump region, resulting in improvement of gain flatness by 2.42 dB. The peak to peak variation of gain is achieved less than 1.6 dB. DWDM system with 16-channel, 25 GHz spaced system has been analyzed thoroughly with hybrid modulated parametric pump amplified Raman-FOPA amplifier for gain flatness and improved performance in terms of BER and Q-factor.

  5. 天地波组网雷达同步控制系统设计%Synchronous Control System Design of Hybrid Sky-Surface Wave Radar Network

    Institute of Scientific and Technical Information of China (English)

    李正勇; 严颂华; 刘志忠; 吴雄斌; 张兰

    2014-01-01

    天地波组网高频地波雷达采用天波发射、地波接收和地波发射、地波接收的形式实现对海洋表面动力学参数如海洋表面流场、风场等的监测,具有覆盖面积广、回波蕴含信息丰富等特点。由于采用收发分置模式,这种组网雷达需要解决接收站与发射站、以及多个接收站之间的同步问题,主要有时间、频率和相位三大同步。针对探测海洋动力学参数的要求,分析了天地波组网雷达对同步的需求,提出了同步控制系统的设计方案,包括基于授时 GPS实现的系统外同步设计以及基于 FPGA实现的系统内同步设计,并给出了相应的硬件和软件实现以及闭环和外场测试结果。该方案解决了天地波组网同步问题,海边进行的天地波组网现场实验也证明了该方案的正确性。%High frequency hybrid sky-surface wave radar network is designed to extract sea surface state parameters such as sea current and wind speed.It works by transmitting both sky wave and ground wave then receiving ground waves,so this radar network has the feature of wide coved area,abundant backward wave information and so on.Since the transmitting stations and the receiving stations are separated,there needs a perfect synchronization system between the separated receivers and transmitters,as well as among multiple receiving stations,which involves time synchronization,frequency synchronization and phase syn-chronization.In order to satisfy the requirement of the radar network,a scheme of synchronous control sys-tem is presented which includes external synchronization sub-system based on GPS and internal synchroniza-tion sub-system based on FPGA.The scheme solves the problem of synchronization for hybrid sky-surface wave radar.The experimental results prove the validity of the proposed scheme.

  6. Study of lower hybrid wave propagation and absorption in a tokamak plasma using hard X-Ray tomography; Etude de la propagation et de l'absorption de l'onde hybride dans un plasma de tokamak par tomographie X haute energie

    Energy Technology Data Exchange (ETDEWEB)

    Imbeaux, F

    1999-09-22

    Control of the current density profile is a critical issue in view to obtain high fusion performances in tokamak plasmas? It is therefore important to be able to control the power deposition profile of the lower hybrid wave, which has the highest current drive efficiency among all other non-inductive additional methods. Propagation and absorption of this wave are investigated in the Tore Supra tokamak using a new hard x-ray tomographic system and a new ray-tracing/Fokker-Planck code. These tools are described in detail and allow to analyse the lower hybrid power deposition profile dependence as a function of various plasma parameters (density, magnetic field, current) and of the injected wave spectrum. A good agreement between the code and the measurements found when the central electron temperature is greater than about 3 keV, that is in regimes where the wave undergoes only a few reflections before being absorbed. The simulations are then used to interpret the experimental trends. The lower hybrid power deposition profile is in nearly all discharges localised at a normalised minor radius of 0.2-0.3, and is weakly sensitive to variations of plasma parameters. It is hence difficult to perform an efficient control of the current profile generated by the lower hybrid wave in Tore Supra. This goal may nevertheless be reached by using an original method, which uses an auxiliary lower hybrid wave injected by a vertical port of the torus. This method is investigated by means of the simulation code. (author)

  7. Desempenho de híbridos de melão do grupo inodorus em Mossoró Performance of melon hybrids of inodorus group in Mossoró, Brazil

    Directory of Open Access Journals (Sweden)

    Glauber Henrique de S. Nunes

    2005-03-01

    Full Text Available Foram conduzidos dois experimentos em Mossoró para avaliar o desempenho de híbridos de melão do grupo inodorus. Em ambos experimentos, foram utilizados delineamentos experimentais em blocos completos casualizados com três repetições. O primeiro experimento foi constituído de dez híbridos Pele de Sapo e o segundo de cinco híbridos de melão do tipo Amarelo e quatro Pele de Sapo. Avaliou-se a produtividade, peso médio do fruto, cavidade interna, espessura da polpa, índice de formato, aparências externa e interna, perda de peso, teor de sólidos solúveis, firmeza da polpa e concentração da produção. No primeiro experimento o híbrido PS RDR destacou-se como o mais promissor, com alta produtividade, alto teor de sólidos solúveis, elevada firmeza de polpa e boa aparência interna e externa. No segundo experimento, os melões do tipo Amarelo diferiram dos melões Pele de Sapo nas características avaliadas. Os híbridos 'Gold Mine' e 'AMR GLDX' tiveram as melhores performances entre os melões tipo Amarelo e o híbrido 'PS 07' entre os melões do tipo Pele de Sapo.Two experiments were carried out in Mossoró, Rio Grande do Norte State, Brazil, to evaluate the performance of melon hybrids of the inodorus group. The experimental design was a randomized complete blocks with three replications. In the first experiment ten 'Piel del Sapo" hybrids were evaluated and in the second five hybrids of Valenciano type of melon and four 'Piel del Sapo' hybrids were evaluated. Evaluations of yield, average fruit weight, format index, internal cavity, pulp thickness, external and intern appearance, weight loss, total soluble solids, pulp firmness and yield concentration, were done. In the first experiment, the hybrid 'PS RDR' was the most promising with high fruit yield and total soluble solids content, better pulp firmness besides good appearance. The Valenciano type of melons differed from 'Piel del Sapo' type of melons for the assessed

  8. Multi-step surface functionalization of polyimide based evanescent wave photonic biosensors and application for DNA hybridization by Mach-Zehnder interferometer

    Energy Technology Data Exchange (ETDEWEB)

    Melnik, Eva [Health and Environment Department, Nano Systems, AIT Austrian Institute of Technology GmbH, Donau-City-Strasse 1, 1220 Vienna (Austria); Department of Analytical Chemistry, University of Vienna, Waehringer Strasse 38, 1090 Vienna (Austria); Bruck, Roman [Health and Environment Department, Nano Systems, AIT Austrian Institute of Technology GmbH, Donau-City-Strasse 1, 1220 Vienna (Austria); Hainberger, Rainer, E-mail: rainer.hainberger@ait.ac.at [Health and Environment Department, Nano Systems, AIT Austrian Institute of Technology GmbH, Donau-City-Strasse 1, 1220 Vienna (Austria); Laemmerhofer, Michael, E-mail: michael.laemmerhofer@univie.ac.at [Department of Analytical Chemistry, University of Vienna, Waehringer Strasse 38, 1090 Vienna (Austria)

    2011-08-12

    Highlights: {yields} We realize a biosensing platform for polyimide evanescent photonic wave sensors. {yields} We show that the surface functionalization via silanisation and biotinylation followed by streptavidin immobilization do not destroy or damage the thin polyimide film. {yields} A highly dense streptavidin layer enables the immobilisation of biotinylated ligands such as biotinylated ssDNA for the selective measurement of DNA hybridization. - Abstract: The process of surface functionalization involving silanization, biotinylation and streptavidin bonding as platform for biospecific ligand immobilization was optimized for thin film polyimide spin-coated silicon wafers, of which the polyimide film serves as a wave guiding layer in evanescent wave photonic biosensors. This type of optical sensors make great demands on the materials involved as well as on the layer properties, such as the optical quality, the layer thickness and the surface roughness. In this work we realized the binding of a 3-mercaptopropyl trimethoxysilane on an oxygen plasma activated polyimide surface followed by subsequent derivatization of the reactive thiol groups with maleimide-PEG{sub 2}-biotin and immobilization of streptavidin. The progress of the functionalization was monitored by using different fluorescence labels for optimization of the chemical derivatization steps. Further, X-ray photoelectron spectroscopy and atomic force microscopy were utilized for the characterization of the modified surface. These established analytical methods allowed to derive information like chemical composition of the surface, surface coverage with immobilized streptavidin, as well as parameters of the surface roughness. The proposed functionalization protocol furnished a surface density of 144 fmol mm{sup -2} streptavidin with good reproducibility (13.9% RSD, n = 10) and without inflicted damage to the surface. This surface modification was applied to polyimide based Mach-Zehnder interferometer

  9. An FDTD algorithm for simulation of EM waves propagation in laser with static and dynamic gain models

    KAUST Repository

    Al-Jabr, Ahmad Ali

    2013-01-01

    This paper presents methods of simulating gain media in the finite difference time-domain (FDTD) algorithm utilizing a generalized polarization formulation. The gain can be static or dynamic. For static gain, Lorentzian and non-Lorentzian models are presented and tested. For the dynamic gain, rate equations for two-level and four-level models are incorporated in the FDTD scheme. The simulation results conform with the expected behavior of wave amplification and dynamic population inversion.

  10. Signs of cosmic rays in gravitational wave detectors;Sinais de raios cosmicos em detectores de ondas gravitacionais

    Energy Technology Data Exchange (ETDEWEB)

    Tavares, Denis Borgarelli

    2010-07-01

    One of the phenomena predicted by Einstein in the derivation of general relativity is the existence of small perturbations of the metric that he named gravitational waves. As they travel through space oscillates the space-time according to its polarization. This is the only major prediction of general relativity not yet proven completely. The small signal generated by the passage of a gravitational wave compared to the noise in the system of detection makes their direct detection one challenge of modern science. In this paper we study the noise generated by cosmic rays in the gravitational antenna Mario Schenberg, located in the city of Sao Paulo. Single muons and hadrons flux measurements held in the northern hemisphere were used to calculate the expected flux of these particles in the city of Sao Paulo. The calculation of the energy deposited in the detector of gravitational waves from cosmic rays was performed by Monte Carlo simulations using Geant4. The transport of muons and protons, with several energy and some different angles of incidence, across the building and the resonant sphere was simulated. We developed a thermo-acoustic model, called multi-point, suitable for calculating the energy deposited in the normal modes from the energy deposited on the sphere by elementary particles. With these results we calculate the expected rate of cosmic ray signals in the main detection mode of gravitational waves, nl = 12, of the Mario Schenberg detector, for temperatures T{sub noise} between 10{sup -5} and 10{sup -7} K. The results showed for the designed for 4.2 K sensitivity of the Mario Schenberg detector that the rate of signals due to cosmic rays is very small, being around 5 events per day. However, when it will reach the quantum limit will be needed a more detailed analysis of the antenna signal output, since the expected number of cosmic ray noise increases considerably, reaching about 250 signals per day. (author)

  11. Real-space and plane-wave hybrid method for electronic structure calculations for two-dimensional materials

    Science.gov (United States)

    Do, V. Nam; Le, H. Anh; Vu, V. Thieu

    2017-04-01

    We propose a computational approach to combining the plane-wave method and the real-space treatment to describe the periodic variation in the material plane and the decay of wave functions from the material surfaces. The proposed approach is natural for two-dimensional material systems and thus may circumvent some intrinsic limitations involving the artificial replication of material layers in traditional supercell methods. In particular, we show that the proposed method is easy to implement and, especially, computationally effective since low-cost computational algorithms, such as iterative and recursive techniques, can be used to treat matrices with block tridiagonal structure. Using this approach we show first-principles features that supplement the current knowledge of some fundamental issues in bilayer graphene systems, including the coupling between the two graphene layers, the preservation of the σ band of monolayer graphene in the electronic structure of the bilayer system, and the differences in low-energy band structure between the AA- and AB-stacked configurations.

  12. A hybrid method for determination of the acoustic impedance of an unflanged cylindrical duct for multimode wave

    Science.gov (United States)

    Snakowska, Anna; Jurkiewicz, Jerzy; Gorazd, Łukasz

    2017-05-01

    The paper presents derivation of the impedance matrix based on the rigorous solution of the wave equation obtained by the Wiener-Hopf technique for a semi-infinite unflanged cylindrical duct. The impedance matrix allows, in turn, calculate the acoustic impedance along the duct and, as a special case, the radiation impedance. The analysis is carried out for a multimode incident wave accounting for modes coupling on the duct outlet not only qualitatively but also quantitatively for a selected source operating inside. The quantitative evaluation of the acoustic impedance requires setting of modes amplitudes which has been obtained applying the mode decomposition method to the far-field pressure radiation measurements and theoretical formulae for single mode directivity characteristics for an unflanged duct. Calculation of the acoustic impedance for a non-uniform distribution of the sound pressure and the sound velocity on a duct cross section requires determination of the acoustic power transmitted along/radiated from a duct. In the paper, the impedance matrix, the power, and the acoustic impedance were derived as functions of Helmholtz number and distance from the outlet.

  13. Hybrid excitations due to crystal field, spin-orbit coupling, and spin waves in LiFePO4

    Science.gov (United States)

    Yiu, Yuen; Le, Manh Duc; Toft-Peterson, Rasmus; Ehlers, Georg; McQueeney, Robert J.; Vaknin, David

    2017-03-01

    We report on the spin waves and crystal field excitations in single crystal LiFePO4 by inelastic neutron scattering over a wide range of temperatures, below and above the antiferromagnetic transition of this system. In particular, we find extra excitations below TN=50 K that are nearly dispersionless and are most intense around magnetic zone centers. We show that these excitations correspond to transitions between thermally occupied excited states of Fe2 + due to splitting of the S =2 levels that arise from the crystal field and spin-orbit interactions. These excitations are further amplified by the highly distorted nature of the oxygen octahedron surrounding the iron atoms. Above TN, magnetic fluctuations are observed up to at least 720 K, with an additional inelastic excitation around 4 meV, which we attribute to single-ion effects, as its intensity weakens slightly at 720 K compared to 100 K, which is consistent with the calculated cross sections using a single-ion model. Our theoretical analysis, using the MF-RPA model, provides both detailed spectra of the Fe d shell and estimates of the average ordered magnetic moment and TN. By applying the MF-RPA model to a number of existing spin-wave results from other Li M PO4 (M =Mn , Co, and Ni), we are able to obtain reasonable predictions for the moment sizes and transition temperatures.

  14. Novel inorganic-organic hybrids constructed from multinuclear copper cluster and Keggin polyanions: from 1D wave-like chain to 2D network.

    Science.gov (United States)

    Wang, Xiuli; Wang, Yufei; Liu, Guocheng; Tian, Aixiang; Zhang, Juwen; Lin, Hongyan

    2011-09-28

    Two novel inorganic-organic hybrids constructed from Keggin-type polyanions and multinuclear copper clusters based on 1-H-1,2,3-benzotriazole (HBTA), [Cu(I)(8)(BTA)(4)(HBTA)(8)(SiMo(12)O(40))]·2H(2)O (1) and [Cu(II)(6)(OH)(4)(BTA)(4)(SiW(12)O(40))(H(2)O)(6)]·6H(2)O (2), have been hydrothermally synthesized and structurally characterized by single crystal X-ray diffraction, elemental analyses, IR spectra and thermogravimetric (TG) analyses. In compound 1, eight Cu(I) ions were linked by twelve HBTA/BTA ligands to form an octanuclear Cu(I) cluster, which is connected by SiMo(12)O(40)(4-) anion with two bridging O atoms and two terminal O atoms to construct a one-dimensional (1D) wave-like chain. The octanuclear copper unit represents the maximum subunit linked just by amine ligands in the POMs system. In 2, four BTA ligands linked five Cu(II) ions constructing a pentanuclear "porphyrin-like" subunit, which is connected by another Cu(II) ion to form a 1D metal-organic band. The SiW(12)O(40)(4-) polyanions as tetradentate inorganic linkages extend the 1D band into a two-dimensional (2D) network with (8(3))(2)(8(5)·10) topology. To the best of our knowledge, compounds 1 and 2 represent the first examples of inorganic-organic hybrids based on metal-HBTA multinuclear subunits and polyoxometalates. The photocatalysis and electrochemical properties have been investigated in this paper.

  15. EFEITO DE ONDAS ULTRA-SÔNICAS SOBRE A POPULAÇÃO DE Leuconostoc mesenteroides EM CALDO DE CANA-DE-AÇÚCAR THE EFFECT OF ULTRASOUND WAVES ON THE Leuconostoc mesenteroides POPULATION IN SUGARCANE JUICE

    Directory of Open Access Journals (Sweden)

    Manoel Soares Soares Júnior

    2007-09-01

    Full Text Available

    No presente trabalho, irradiou-se caldo de cana-de-açúcar de primeira extração, com ondas ultra-sônicas, com o objetivo de controlar a bactéria <em>Leuconostoc mesenteroidesem>. Foi aplicada a metodologia de superfície de resposta (modelo central composto, para avaliar o efeito dos tratamentos. A variável resposta avaliada foi taxa de mortalidade (TM% da população de <em>L. mesenteroidesem>. Os resultados mostraram que a maior taxa de mortalidade, 10,55%, foi obtida com a potência de 50 W, por 225 segundos, em caldo de cana com 18° Brix, pH 4,5 e 45°C.

    PALAVRAS-CHAVE: Indústria açucareira; cana-de-açúcar; ultra-som.

    In the present work, first extraction sugarcane juice was irradiated with ultrasound waves to control <em>Leuconostoc mesenteroidesem>. Surface response methodology (central composite model was used to evaluate the treatment effects. The response variable was the death rate (DR% of the <em>L. mesenteroidesem> population. The results showed that the highest rate of mortality, 10.55%, was obtained with a power of 50 W for 225 seconds, in sugarcane juice with 18° Brix, pH 4.5 and 45°C.

    KEY-WORDS: Sugar industry; sugarcane; ultrasound.

  16. Cultivo de híbridos de pimentão amarelo em fibra da casca de coco Performance of yellow sweet peppers hybrids grown in coconut husk fiber

    Directory of Open Access Journals (Sweden)

    Hamilton César de O Charlo

    2009-06-01

    Full Text Available Objetivou-se avaliar a produtividade de cinco híbridos de pimentão amarelo em ambiente protegido, utilizando fibra de casca de coco e fertirrigação. Adotou-se o delineamento em blocos casualizados, com cinco cultivares (Zarco, CLXP 1463, Línea, Matador e Eppo, e quatro repetições, sendo cada parcela constituída por onze plantas. O cultivo de pimentão foi feito em sistema aberto em vasos plásticos de 13 L, transplantando-se uma muda por vaso, as quais foram produzidas em bandejas de poliestireno expandido. Adotou-se o espaçamento de 0,8 m entre fileiras simples, 1,10 m entre fileiras duplas e 0,5 m entre plantas. As plantas foram conduzidas com quatro hastes principais e tutoradas individualmente em forma de "V". A colheita dos frutos foi realizada quando estes atingiam o tamanho ideal e, no mínimo, 70% da coloração amarela. Avaliaram-se o comprimento e o diâmetro médio dos frutos, a relação comprimento/diâmetro, a espessura da polpa, o teor de sólidos solúveis totais, o pH, o número de frutos por planta, a massa total de frutos por planta, o peso médio dos frutos, a produtividade total e comercial, e a classificação dos frutos. O híbrido CLXP 1463 produziu frutos de maior comprimento e diâmetro. Este híbrido apresentou menor número de frutos por planta, porém com maior massa. Para as características espessura da polpa, sólidos solúveis totais e pH não se verificou diferença significativa entre os híbridos. Os híbridos CLXP 1463, Eppo e Matador se mostraram promissores, com produtividades comerciais de 107,61; 102,62 e 95,31 t ha-1, respectivamente. Os híbridos CLXP 1463, Eppo, Línea e Matador apresentaram toda a produção classificada como Extra.The yield of five yellow sweet pepper hybrids was evaluated in protected cultivation, using coconut fiber and fertirrigation. The experiment was arranged in a randomized blocks design, with five cultivars (Zarco, CLX 1463, Línea, Matador and Eppo and four

  17. Ag-Ag2S/reduced graphene oxide hybrids used as long-wave UV radiation emitting nanocomposites

    Science.gov (United States)

    Li, Wenyao; Xu, Ruoyu; Ling, Min; He, Guanjie

    2017-10-01

    We report a facile thermal decomposition approach to synthesize Ag-Ag2S/reduced graphene oxide (Ag-Ag2S/rGO), the Ag-Ag2S nanoparticles uniformly dispersed on reduced graphene oxide with diameters of 10-20 nm. The photoluminescence spectra of Ag-Ag2S/rGO showed two obvious emission peaks at 327 and 339 nm with the excitation wavelength at 287 nm. Compared with Ag-Ag2S heterostructured clusters with two peaks at 407 and 430 nm, it showed a big blue shift and higher intensity, which makes it a novel candidate for long-wave UV radiation emitting nanocomposite.

  18. Hybrid multilevel plane wave based near-field far-field transformation utilising combined near- and far-field translations

    Directory of Open Access Journals (Sweden)

    C. H. Schmidt

    2009-05-01

    Full Text Available The radiation of large antennas and those operating at low frequencies can be determined efficiently by near-field measurement techniques and a subsequent near-field far-field transformation. Various approaches and algorithms have been researched but for electrically large antennas and irregular measurement contours advanced algorithms with low computation complexity are required. In this paper an algorithm employing plane waves as equivalent sources and utilising efficient diagonal translation operators is presented. The efficiency is further enhanced using simple far-field translations in combination with the expensive near-field translations. In this way a low complexity near-field transformation is achieved, which works for arbitrary sample point distributions and incorporates a full probe correction without increasing the complexity.

  19. Qualidade das silagens de três híbridos de sorgo ensilados em cinco diferentes estádios de maturação Silage quality of three hybrids of sorghum ensiled at five different maturation stages

    Directory of Open Access Journals (Sweden)

    V.L. Araújo

    2007-02-01

    Full Text Available Foram avaliadas as silagens de três híbridos de sorgo de média altura (BR700, BR701 e MASSA 03. Os híbridos foram cortados em cinco diferentes estádios de maturação. Foram avaliados os teores de matéria seca total, pH, teores de nitrogênio amoniacal em porcentagem de nitrogênio total, porcentagem de proteína bruta, frações fibrosas, digestibilidade in vitro da matéria seca e teores de ácidos orgânicos. O delineamento experimental utilizado foi de blocos inteiramente ao acaso com três repetições. Os tratamentos foram arranjados em esquema fatorial 5x3 (estádio de maturação ´ híbrido. As médias foram comparadas pelo teste SNK (PThree hybrids of sorghum with medium height (BR700, BR701 e MASSA 03 for silage production were evaluated. Hybrids were harvest at five different maturation stages. Dry matter content, pH, ammonia nitrogen, crude protein, fibrous fractions, in vitro dry matter digestibility and organic acids were determined in silage. A completely randomized block design with three replicates was used. The treatments consisted in a factorial arrangement 5x3 (maturation stages x hybrids. The means were compared by SNK test (P<0.05. Dry matter content and pH values increased with the maturation stage; pH values were always lower than 4.09. No effects of maturation stage of the plant on ammonia nitrogen, fibrous fractions and in vitro dry matter digestibility were found. Organic acids contents suggested that the fermentation inside the silo was enough for preservation of the forage.

  20. Meiotic behavior in Panicum maximum Jacq. (Poaceae: Panicoideae: Paniceae: hybrids and their genitors = Comportamento meiótico em Panicum maximum Jacq. (Poaceae: Panicoideae: Paniceae: híbridos e seus progenitores

    Directory of Open Access Journals (Sweden)

    Cleide Pessim

    2010-07-01

    Full Text Available Panicum maximum Jacq. is one of the most cultivated grasses in the world. The intraspecific hybridization breeding program underway at Embrapa Beef Cattle aims at combining several agronomic characteristics in a single plant with high seed production. Four intraspecific hybrids originated from the cross between sexual tetraploid female plants with apomictic tetraploid male plants, including the genitors, were cytologically evaluated in the meiotic process throughout conventional methodology. Hybrids and genitors showed high meiotic stability. The percentage of abnormal cells among them ranged from 6.7 to 14.2%. Abnormalities recorded were irregular chromosome segregation, chromosome stickiness, and absence of the first cytokinesis, but the latter did not compromise pollen viability. Multivalent chromosome configurations at diakinesis, ranging from one to three quadrivalents, suggest that genetic recombination and introgression of some genes can be expected in the hybrids. Based on meiotic stability, the hybrids should be selected for high seed production, and the genitors could remain in the program participating in other intraspecific crosses.Panicum maximum Jacq. é uma das gramíneas mais cultivadas no mundo. O programa de hibridização intraespecífica, desenvolvido pela Embrapa Gado de Corte objetiva combinar diversas características agronômicas em uma única planta com alta produção de sementes. Quatro híbridosintraespecíficos, originados a partir do cruzamento entre fêmeas sexuais tetraploidizadas artificialmente com plantas apomíticas, incluindo os respectivos genitores, foram citologicamente avaliados em seu processo meiótico por meio de metodologia convencional.Híbridos e genitores apresentaram alta estabilidade meiótica, e a percentagem de anormalidades meióticas entre eles variou de 6,7 a 14,2%. As anormalidades encontradas foram segregação irregular de cromossomos, aderências e ausência de citocinese, mas esta

  1. Evolution of a hybrid micro-macro entangled state of the qubit-oscillator system via the generalized rotating wave approximation

    Science.gov (United States)

    Chakrabarti, R.; Yogesh, V.

    2016-04-01

    We study the evolution of the hybrid entangled states in a bipartite (ultra) strongly coupled qubit-oscillator system. Using the generalized rotating wave approximation the reduced density matrices of the qubit and the oscillator are obtained. The reduced density matrix of the oscillator yields the phase space quasi probability distributions such as the diagonal P-representation, the Wigner W-distribution and the Husimi Q-function. In the strong coupling regime the Q-function evolves to uniformly separated macroscopically distinct Gaussian peaks representing ‘kitten’ states at certain specified times that depend on multiple time scales present in the interacting system. The ultrastrong coupling strength of the interaction triggers appearance of a large number of modes that quickly develop a randomization of their phase relationships. A stochastic averaging of the dynamical quantities sets in, and leads to the decoherence of the system. The delocalization in the phase space of the oscillator is studied by using the Wehrl entropy. The negativity of the W-distribution reflects the departure of the oscillator from the classical states, and allows us to study the underlying differences between various information-theoretic measures such as the Wehrl entropy and the Wigner entropy. Other features of nonclassicality such as the existence of the squeezed states and appearance of negative values of the Mandel parameter are realized during the course of evolution of the bipartite system. In the parametric regime studied here these properties do not survive in the time-averaged limit.

  2. Direct generation of graphene plasmonic polaritons at THz frequencies via four wave mixing in the hybrid graphene sheets waveguides.

    Science.gov (United States)

    Sun, Yu; Qiao, Guofu; Sun, Guodong

    2014-11-17

    A compact waveguide incorporating a high-index nano-ridge sandwiched between graphene sheets is proposed for the direct generation of graphene plasmonic polaritons (GSPs) via four wave mixing (FWM). The proposed waveguide supports GSP modes at the THz frequencies and photonic modes at the infrared wavelengths. Due to the strong confinement of coupled graphene sheets, the GSP modes concentrate in the high-index nano-ridge far below the diffraction limit, which improves integral overlap with the photonic modes and greatly facilitates the FWM process. To cope with the ultra-high effective refractive of the GSP modes, an alternative energy conservation diagram is selected for the degenerated FWM, which corresponds to one pump photon transfers its energy to two signal photons and one GSP photon. The single mode condition of the generated symmetric GSP modes is analyzed by the effective index method to suppress the undesired conversion. Due to the unique tunability of GSPs, the phase matching condition can be satisfied by tuning the chemical potential of the graphene sheets employing external gates. The FWM pumped at 1,550 nm with a peak power of 1 kW is theoretically investigated by solving the modified coupled mode equations. The generated GSP power reaches its maximum up to 67 W at a propagation distance of only 43.7 μm. The proposed waveguide have a great potential for integrated chip-scale GSP source.

  3. Study of Scrape-Off-Layer Width in Ohmic and Lower Hybrid Wave Heated Double-Null Divertor Plasma in EAST%Study of Scrape-Off-Layer Width in Ohmic and Lower Hybrid Wave Heated Double-Null Divertor Plasma in EAST

    Institute of Scientific and Technical Information of China (English)

    王亮; 刘鹏; 蒋敏; 熊豪; 万宝年; 高翔; 郭后扬; 胡立群; 吴振伟; 朱思铮; 罗广南; 徐国盛; 常加峰; 张炜; 颜宁; 丁斯晔; 刘少承; 明廷凤; 汪惠乾

    2011-01-01

    Edge profiles in Ohmic and lower hybrid (LH) wave heated discharges in EAST are presented. A comparison of the measured profiles is made with those from the theoretical prediction for the scrape-off-layer (SOL) width. The edge plasma parameters are diagnosed by a triple probe divertor diagnostic system and fast reciprocating probes at the outer mid-plane. The experimental results show that the SOL width of double-null (DN) divertor plasmas in EAST appears to exhibit a negative dependence on the power crossing the separatrix, which is consistent with the collisional SOL scalings of JET and Alcator C-Mod. This will provide useful information for extrapolation to the ITER SOL width scaling for power deposition.

  4. Dispersion of complex permeability and EM-wave absorbing characteristics of polymer-based composites with dual ferrite filler

    Energy Technology Data Exchange (ETDEWEB)

    Dosoudil, Rastislav [Faculty of Electrical Engineering and Information Technology, Ilkovicova3, 81219Bratislava (Slovakia)], E-mail: rastislav.dosoudil@stuba.sk; Usakova, Marianna; Franek, Jaroslav; Gruskova, Anna; Slama, Jozef [Faculty of Electrical Engineering and Information Technology, Ilkovicova3, 81219Bratislava (Slovakia)

    2008-10-15

    Triple-component PVC-polymer-based composites with MnZn and LiZn ferrites were synthesized by a dry hot-pressing route and their complex permeability and electromagnetic wave absorption characteristics have been studied in the frequency interval of 10 kHz-1 GHz. The model concerning the domain wall and magnetization rotation dynamics was used to decompose the measured spectra of sintered ferrites and composites into the contributions of the resonance of oscillating domain walls and the natural (ferromagnetic) resonance of precessing magnetic moments in domains. The permeability, resonance frequency, return loss (RL) and bandwidth (for RL{<=}-20 dB) can be better tuned in triple-component composites than in those with single ferrite fillers.

  5. Condutividade elétrica em sementes de abóbora, híbrido Bárbara Electrical conductivity of pumpkin hybrid Bárbara seeds

    Directory of Open Access Journals (Sweden)

    Roberval Daiton Vieira

    2006-09-01

    Full Text Available A condutividade elétrica na solução de embebição de sementes tem sido um procedimento usado com sucesso para avaliar o vigor de sementes. A presente pesquisa foi desenvolvida com o objetivo de determinar os procedimentos adequados para o teste de condutividade elétrica de sementes de abóbora (Cucurbita moschata Duch ex. Lam. Foram utilizadas sementes do híbrido Bárbara, representadas por cinco lotes (1 a 5 na primeira etapa e por outros cinco (6 a 10 na segunda. Foram realizados os teste de germinação, primeira contagem de germinação, emergência de plântulas, índice de velocidade de emergência e de condutividade elétrica (CE. Para o teste de CE, foram estudadas variações no volume de água (50 e 75mL, na temperatura (20, 25 e 30ºC e no tempo de embebição (1, 2, 4, 8, 12, 16, 20 e 24 horas. Assim, concluiu-se que a condição mais adequada para o teste de CE é a utilização de 50 sementes em 75mL de água por oito horas, à temperatura de 25ºC.The electrical conductivity in the soaked seed solution has been used successfully to evaluate seed vigor. This work was developed with the objective of determining the adequate procedures to evaluate the electrical conductivity test of pumpkin (Cucurbita moschata Duch ex. Lam seeds. For pumpkin, hybrid Bárbara, five lots of seeds, in both stages, were used, all with quality patterns (germination above the minimum demanded by commercialization. The standard germination, first countig of germination, seedling emergency, and emergency speed index and electrical conductivity (EC test were run. For the EC test two volumes of water (50 and 75mL, three temperatures (20, 25 and 30ºC and eight period of seed soaking (1, 2, 4, 8, 12, 16, 20 and 24 hours were used. So, it can be concluded that the EC test can be conducted using 50 seeds, 25ºC, 75mL and 8h of embibition period for pumpkin seeds.

  6. Tolerância à toxicidade de alumínio de linhagens e híbridos de milho em solução nutritiva Aluminium toxicity tolerance of maize inbred lines and hybrids evaluated in nutrient solution

    Directory of Open Access Journals (Sweden)

    Maria Elisa Ayres Guidetti Zagatto Paterniani

    2002-04-01

    Full Text Available Avaliaram-se dez linhagens de milho do programa de melhoramento do Instituto Agronômico (IAC, em cruzamentos dialélicos e os 45 híbridos resultantes quanto à tolerância à toxicidade de alumínio em laboratório. Estimou-se a tolerância pelo comprimento líquido da radícula (CLR de plântulas em solução nutritiva contendo 4,5 mg.L-1 de alumínio, em ensaio sob delineamento experimental de blocos casualizados com quatro repetições, utilizando-se como padrões linhagens sensível e tolerante de IAC Taiúba. Apresentam-se, ainda, resultados da produtividade desses cruzamentos em ensaios de campo. Identificaram-se linhagens que constituem fontes de tolerância (L 06 e L 09 e híbridos tolerantes à toxicidade de alumínio com elevada produtividade em solos corrigidos. Na análise dialélica, o desdobramento dos efeitos de tratamentos, em capacidade geral (CGC e específica (CEC de combinação, indicou a predominância de efeitos aditivos na manifestação da tolerância ao alumínio tóxico. Obtiveram-se elevados valores de heterose, indicando a existência de interações não alélicas na manifestação do CLR. O híbrido HS 10X11 (denominado IAC 21 aliou alta produtividade e tolerância ao alumínio, apresentando a maior estimativa da CEC para CLR.Ten inbred lines and the resulting forty-five hybrids from the maize IAC breeding program were evaluated for Al tolerance by the nutrient solution technique. Net radicle lengths (CLR of plants grown with 4.5 mg.L-1 were used to estimate Al tolerance. The experimental design was randomized complete block with four replications, and it was used two divergent inbred lines IAC Taiuba as control for Al tolerance and sensitivity, respectively. In addition to these data, it is shown also the grain yield of the same materials from field plots. It was identified two inbred lines (L 06 and L 09 as Al tolerance sources and hybrids potentially adapted to acid soil conditions (tolerant to Al toxicity

  7. Efeito da tristeza em caracteres vegetativos, produtivos e industriais da laranjeira 'Valência' enxertada em híbridos segregando para tolerância Effect of the citrus tristeza disease on vegetative, productive and industrial characters of 'Valencia' sweet orange grafted onto hybrid rootstocks segregating for tolerance

    Directory of Open Access Journals (Sweden)

    Rita Bordignon

    2003-01-01

    ólidos solúveis aumentou significativamente, 14% em média, nos híbridos intolerantes.The effect of the citrus tristeza disease caused by CTV on vegetative, productive, and industrial characters of the sweet orange 'Valencia' grafted onto seven hybrid progenies of full sibs segregating for tolerance was studied. The hybrids were originated from controlled crosses between the commercial rootstocks 'Davis A' Poncirus trifoliata (T, Sunki mandarin (S, 'São Paulo' sour orange (A and 'Limeira' Rangpur lime (C. Two sets of hybrids were studied. The first was formed by 298 individuals, from which 20 were T x S, 67 S x T, 98 S x A, 48 C x A, and 65 T x A. The second set had 1.243 hybrids, being 845 S x A, 240 A x S, 139 C x A, and 19 A x C. In the nursery, tristeza disease was responsible for 21% of death among the intolerant individuals, while among survivors transplanted to the field, an additional 13% died in a four-years period. Among the intolerant survivors in the field, tristeza reduced in four years rootstock diameter to 41%, scion diameter in 45%, and general vigor in 42%. Fruit weight was reduced in 22% in average. Yield was the most drastically affected character, being reduced to 41% in the first harvest, and up to 90% in the fifth harvest. Accumulated yields of five years were reduced 85% in the intolerant segregants among the different groups of hybrids. Productivity (yield/area of canopy was also intensely affected (46% indicating that the reduction in yield was proportionally more intense than the correspondent reduction in the vegetative growth. The relation between scion/rootstock diameters decreased 7% in the intolerant plants. Although small, it indicated that the vegetative growth of the tolerant canopies was more affected than the rootstocks, despite their intolerance. Little or no effect was detected on external peel color, juice outturn, and soluble solids/acids ratio. Acidity and soluble solids significantly increased at an average of 12 and 14

  8. Rendimento de grãos de híbridos de milho em duas densidades de plantas com e sem a retirada dos perfilhos Grain yield of maize hybrids at two plant densities with and without tillers removal

    Directory of Open Access Journals (Sweden)

    Luís Sangoi

    2009-04-01

    Full Text Available O milho não possui um mecanismo efetivo de compensação de espaços vazios na lavoura. Desse modo, híbridos perfilhadores podem ser mais eficientes no aproveitamento dos recursos ambientais, principalmente sob baixas populações de plantas. Este trabalho foi conduzido com o objetivo de avaliar o desempenho agronômico de híbridos de milho cultivados em duas densidades de plantas, com e sem a presença de perfilhos. O ensaio foi implantado em Lages, Santa Catarina, nos anos agrícolas de 2005/2006 e 2006/2007. Foram avaliados três híbridos: AS1560, PENTA e P30F53. Cada híbrido foi cultivado nas densidades de 4,0 e 7,0pl m-2, mantendo-se os perfilhos produzidos até o final do ciclo ou removendo-os quando as plantas estavam com nove folhas expandidas. Foram determinados a percentagem de plantas perfilhadas em quatro estádios fenológicos da cultura, o rendimento de grãos e os componentes do rendimento. Os híbridos P30F53 e AS 1560 perfilharam mais que o PENTA na densidade de 4pl m-2. No primeiro ano do estudo, o destino dos perfilhos não interferiu sobre o rendimento de grãos. Em 2006/2007, a manutenção dos perfilhos propiciou maior rendimento de grãos que a sua remoção para todos os híbridos avaliados, na densidade de 4pl m-2. Os resultados obtidos no trabalho demonstraram que a remoção dos perfilhos não traz benefícios ao desempenho agronômico do milho e que a sua manutenção pode incrementar o rendimento de grãos quando a lavoura é conduzida com baixas densidades de plantas.Maize does not have an effective mechanism to compensate empty spaces in the field. Therefore, tillering hybrids may be more efficient to use environmental resources, especially under low plant populations. This reserach was carried out aiming to evaluate the agronomic performance of maize hybrids grown at two plant densities, with and without tiller's presence. The experiment was set in Lages, SC, Brazil, during the 2005/2006 and 2006/2007 growing

  9. Multifunctional hybrids for electromagnetic absorption

    Energy Technology Data Exchange (ETDEWEB)

    Huynen, I. [Research Center in Micro and Nanoscopic Materials and Electronic Devices, CeRMiN, Universite catholique de Louvain, B-1348 Louvain-la-Neuve (Belgium); Information and Communications Technologies, Electronics and Applied Mathematics (ICTEAM), Microwave Laboratory, Universite catholique de Louvain, B-1348 Louvain-la-Neuve (Belgium); Quievy, N. [Institute of Condensed Matter and Nanosciences (IMCN), Universite catholique de Louvain, B-1348 Louvain-la-Neuve (Belgium); Bailly, C. [Research Center in Micro and Nanoscopic Materials and Electronic Devices, CeRMiN, Universite catholique de Louvain, B-1348 Louvain-la-Neuve (Belgium); Institute of Condensed Matter and Nanosciences (IMCN), Universite catholique de Louvain, B-1348 Louvain-la-Neuve (Belgium); Institute of Mechanics, Materials and Civil Engineering (iMMC), Universite catholique de Louvain, B-1348 Louvain-la-Neuve (Belgium); Bollen, P. [Information and Communications Technologies, Electronics and Applied Mathematics (ICTEAM), Microwave Laboratory, Universite catholique de Louvain, B-1348 Louvain-la-Neuve (Belgium); Institute of Condensed Matter and Nanosciences (IMCN), Universite catholique de Louvain, B-1348 Louvain-la-Neuve (Belgium); Institute of Mechanics, Materials and Civil Engineering (iMMC), Universite catholique de Louvain, B-1348 Louvain-la-Neuve (Belgium); Detrembleur, C. [Center for Education and Research on Macromolecules (CERM), University of Liege, Sart-Tilman B6a, 4000 Liege (Belgium); Eggermont, S.; Molenberg, I. [Information and Communications Technologies, Electronics and Applied Mathematics (ICTEAM), Microwave Laboratory, Universite catholique de Louvain, B-1348 Louvain-la-Neuve (Belgium); Thomassin, J.M.; Urbanczyk, L. [Center for Education and Research on Macromolecules (CERM), University of Liege, Sart-Tilman B6a, 4000 Liege (Belgium)

    2011-05-15

    Highlights: > EM absorption requires low dielectric constant and {approx}1 S/m electrical conductivity. > New hybrids were processed with CNT-filled polymer foam inserted in Al honeycomb. > The EM absorption in the GHz range is superior to any known material. > A closed form model is used to guide the design of the hybrid. > The architectured material is light with potential for thermal management. - Abstract: Electromagnetic (EM) interferences are ubiquitous in modern technologies and impact on the reliability of electronic devices and on living cells. Shielding by EM absorption, which is preferable over reflection in certain instances, requires combining a low dielectric constant with high electrical conductivity, which are antagonist properties in the world of materials. A novel class of hybrid materials for EM absorption in the gigahertz range has been developed based on a hierarchical architecture involving a metallic honeycomb filled with a carbon nanotube-reinforced polymer foam. The waveguide characteristics of the honeycomb combined with the performance of the foam lead to unexpectedly large EM power absorption over a wide frequency range, superior to any known material. The peak absorption frequency can be tuned by varying the shape of the honeycomb unit cell. A closed form model of the EM reflection and absorption provides a tool for the optimization of the hybrid. This designed material sets the stage for a new class of sandwich panels combining high EM absorption with mass efficiency, stiffness and thermal management.

  10. Número mínimo de colheitas em pepino híbrido estimado por meio do coeficiente de repetibilidade Minimum harvest number in hybrid cucumber estimated by repeatability coefficient

    Directory of Open Access Journals (Sweden)

    Antonio Ismael Inácio Cardoso

    2006-01-01

    Full Text Available O objetivo deste trabalho foi estimar o número mínimo de colheitas em experimento com a cultura do pepino. Foram analisados dados de um experimento onde avaliaram-se 14 híbridos de pepino japonês, no delineamento em blocos ao acaso, com quatro repetições e cinco plantas por parcela, conduzidas sob ambiente protegido. Foram efetuadas 32 colheitas, três colheitas por semana, por um período de 72 dias e estimados os coeficientes de repetibilidade, com base na análise de componentes principais para os caracteres produção de frutos por planta, em massa e número, total e comercial. Os resultados permitiram concluir que menos de nove colheitas foram suficientes para analisar as diferenças de produtividade entre os diferentes híbridos, com 95% de certeza de serem eleitos os mais produtivos.The objective of this work was to estimate the minimum harvest number in experiments with cucumber. Data of an experiment comparing 14 japanese cucumber hybrids in the randomized block design, with four replications and five plants per plot, under protected cultivation, were analyzed. Thirty-two harvestings were made, three harvests a week, during 72 days to estimate repeatability coefficient based on analysis of the principal components for number and weight of total and commercial fruits per plant. Results allowed to conclude that less than nine harvestings were enough to verify yield differences among hybrids, with 95% of probability to identify the highest yielding ones.

  11. Global Coronal Waves

    CERN Document Server

    Chen, P F

    2016-01-01

    After the {\\em Solar and Heliospheric Observatory} ({\\em SOHO}) was launched in 1996, the aboard Extreme Ultraviolet Imaging Telescope (EIT) observed a global coronal wave phenomenon, which was initially named "EIT wave" after the telescope. The bright fronts are immediately followed by expanding dimmings. It has been shown that the brightenings and dimmings are mainly due to plasma density increase and depletion, respectively. Such a spectacular phenomenon sparked long-lasting interest and debates. The debates were concentrated on two topics, one is about the driving source, and the other is about the nature of this wavelike phenomenon. The controversies are most probably because there may exist two types of large-scale coronal waves that were not well resolved before the {\\em Solar Dynamics Observatory} ({\\em SDO}) was launched: one is a piston-driven shock wave straddling over the erupting coronal mass ejection (CME), and the other is an apparently propagating front, which may correspond to the CME frontal...

  12. Identification and Characterization of a <em>Bursaphelenchus xylophilusem> (Aphelenchida: Aphelenchoididae Thermotolerance-Related Gene: <em>Bx-HSP90em>

    Directory of Open Access Journals (Sweden)

    Danlei Li

    2012-07-01

    Full Text Available Temperatures directly influence the distribution and intensity of pine wilt disease caused by the pine wood nematode, <em>Bursaphelenchus xylophilusem>. To date, however, little is known about the causation and mechanism of this influence. The molecular chaperone HSP90 is a key component that contributes to survival in the abiotic stress response. In this study, we investigated the relationship between the survival of <em>B. xylophilusem> and the functionality of the HSP90 gene<em>.> <em>Bx-HSP90 em>was cloned from a suppression subtractive hybridization library. <em>In situem> mRNA hybridization showed that <em>Bx-HSP90em> was constitutively expressed in response to all of the temperatures tested, and RT-PCR indicated that all of the temperatures could induce <em>Bx-HSP90 em>transcription, with the highest transcript level detected at 30 °C. The suppression of the <em>Bx-HSP90em> transcript by RNA interference led to a 25% reduction in the number of nematodes at 30 °C after 44 h. Sharp declines in the survival of the RNAi-treated nematodes were observed after 8 days at 25 °C, 48 h at 30 °C and 24 h at 35 °C. Both heat shock and the knockdown of <em>Bx-HSP90 em>hindered the growth of the <em>B. xylophilusem> populations. The results indicate that <em>Bx-HSP90em> is essential for the survival of <em>B. xylophilusem>, confirming the thermoregulatory function of the gene, and delineate the timeframe and temperature range within which the gene function occurs.

  13. Características agronômica de híbridos diploides de bananeira em três ciclos de produção em Cruz das Almas, Bahia Agronomic traits of banana diploid hybrids in three cycle of production in Cruz das Almas, Bahia

    Directory of Open Access Journals (Sweden)

    Lauro Saraiva Lessa

    2010-03-01

    Full Text Available O objetivo deste trabalho foi avaliar agronomicamente híbridos diploides de bananeira, em três ciclos de produção, visando à seleção de genótipos para utilização em programas de melhoramento. O experimento foi conduzido entre os anos de 2005 e 2007, em blocos casualizados, no esquema de parcela subdividida no tempo, com quatro repetições, em Cruz das Almas, Bahia. Os híbridos diploides 4279-06, TH03-01, 8987-01, 0323-03, 1318-01, 0116-01, 8694-20, 1304-06 e 9179-03 foram avaliados quanto à altura de plantas, diâmetro do pseudocaule, número de folhas vivas na floração e na colheita, presença de pólen, período de formação do cacho, número de pencas e frutos, e massa média dos frutos. O híbrido 1304-06 apresentou a maior altura nos três ciclos estudados, enquanto o 0323-03 e o 1318-01 apresentaram porte intermediário. À exceção des 8987-01, 0323-03, 1304-06 e 9179-03, os demais híbridos apresentaram número de folhas, na floração, superior a oito. Na colheita, 0323-03, 1318-01, 0116-01, 1304-06 e 9179-03 destacaram-se com os maiores números de folhas. Existe variabilidade genética entre os híbridos diploides de bananeira estudados. Os híbridos 4279-06, 0323-03, 1318-01, 0116-01, 1304-06 e 9179-03 apresentaram características agronômicas favoráveis e podem ser utilizados como genitores em programas de melhoramento genético da bananeira.Objective this work was to evaluate agronomic traits of banana diploid hybrids, in three production cycles, seeking the selection of genotypes for use in banana breeding programs. Experiment was conducted between years 2005 and 2007, at complete randomized block in split plot design, with four replicates, in Cruz das Almas, Bahia, Brazil. Diploids hybrids 4279-06, TH03-01, 8987-01, 0323-03, 1318-01, 0116-01, 8694-20, 1304-06 and 9179-03, were evaluated regarding the characters plant height, pseudostem diameter, number of fresh leaves in flowering and harvest, pollen presence

  14. Hybrid membranes PVA/silicon for use in fuel cells; Membranas hibridas de PVA/silica para aplicacao em celula a combustivel

    Energy Technology Data Exchange (ETDEWEB)

    Aguiar, Liz C.V. de; Almeida, Raquel D. de; Gomes, Ailton de S. [Universidade Federal do Rio de Janeiro - UFRJ, Instituto de Macromoleculas Professora Eloisa Mano - IMA, RJ (Brazil)], e-mail: lizcontino@ima.ufrj.br; Ramos Filho, Florencio G. de [Centro Universitario Estadual da Zona Oeste - UEZO, Rio de Janeiro, RJ (Brazil)

    2011-07-01

    Hybrids organic-inorganic membranes PVA-silica have been prepared using sol-gel process in situ with the objective of study the influence of inorganic particles incorporation on the water uptake, pervaporation and proton conductivity of PVA membranes. The silica was constituted of mercaptopropyltrimethoxysilane (MPTMS) with or without the mixture with the tetra ethoxysilane (TEOS). The hybrids membranes were oxidated to convert the -SH groups in -SO{sub 3}H groups, becoming them proton conducting. The hybrids membranes not oxidated showed lesser water uptake and pervaporated material, probably, due to the formation of crosslink that restricted the swell of the PVA membrane. The protonic conductivity of the hybrid membranes after the oxidation was up to 26 times bigger than of the membrane not oxidated. (author)

  15. Desempenho de híbridos de tomate de crescimento indeterminado em função de sistemas de condução de plantas Performance of tomato hybrids of indeterminate growth depending on training systems

    Directory of Open Access Journals (Sweden)

    Evandro S Matos

    2012-06-01

    Full Text Available O presente trabalho teve como objetivo avaliar dois sistemas de tutoramento e condução de plantas na produtividade e seus componentes em híbridos de tomateiro dos segmentos Salada Longa Vida e Santa Cruz de crescimento indeterminado, visando ao consumo in natura. Adotou-se o delineamento em blocos ao acaso com os tratamentos em esquema fatorial 5x2, quatro repetições, sendo avaliados cinco híbridos comerciais, três pertencentes ao grupo Salada Longa Vida ('Alambra', 'Paron' e 'Forty' e dois do grupo Santa Cruz ('Débora Pto' e 'Ellus', em dois sistemas de condução de plantas (bambu e fitilho. O experimento foi conduzido em condições de campo, em Itatiba (SP, de julho de 2007 a janeiro de 2008. Foram consideradas todas as plantas de cada parcela e avaliaram-se a produtividade total, produtividade comercial, produção por planta, massa média de frutos, número total de frutos, número de frutos comercializáveis, número de frutos das classes '3A', '2A' e '1A', número de frutos manchado e com lóculo aberto. Não houve interação entre cultivar e sistema de condução de planta para maioria das características avaliadas, exceto número total de frutos, número de frutos comercializáveis e número de frutos da classe '2A'. O sistema de condução de plantas com uma haste tutorada com fitilho proporcionou incremento na massa média de frutos e número de frutos da classe '3A', e decréscimo do número de frutos da classe '1A', sem reduzir a produtividade total e comercial quando comparado ao método de condução tradicional no bambu com duas hastes por planta.The objective of this work was to determine the effect of training and of two staking systems for plants on yield potential and its components of tomato hybrids of the Salad Extended Shelf Life and Santa Cruz types of indeterminate growth, aiming in natura market. In this experiment we adopted the randomized block design with the treatments in a 5x2 factorial scheme, and four

  16. RELAÇÕES HÍDRICAS EM DOIS HÍBRIDOS DE MILHO SOB DOIS CICLOS DE DEFICIÊNCIA HÍDRICA WATER RELATIONS IN TWO HYBRIDS OF CORN UNDER TWO CYCLES OF WATER STRESS

    Directory of Open Access Journals (Sweden)

    CARLOS PIMENTEL

    1999-11-01

    Full Text Available Neste trabalho foram estudadas as relações hídricas de dois híbridos de milho (Zea mays L., em casa de vegetação: o IAC 8222 (híbrido com tolerância ambiental e o DINA 10 (híbrido comum; submetidos a um ou a dois ciclos de estresse, aos 30 e 46 DAP. O IAC 8222 manteve o potencial hídrico de folha (psihf superior ao do DINA no primeiro ciclo de estresse e no segundo ciclo, em plantas que sofreram os dois ciclos (com endurecimento, no sexto e último dia de deficiência hídrica, não havendo diferenças em relação ao conteúdo hídrico relativo (CHR entre os híbridos. Houve um aumento da concentração de açúcares solúveis e de aminoácidos com a deficiência hídrica, sem diferenças entre os híbridos no primeiro ciclo de déficit hídrico, e com aumento significativo somente na concentração de aminoácidos no DINA 10 submetido aos dois ciclos, no último dia do segundo ciclo. A concentração de K+ não variou nem com os ciclos nem entre híbridos. Portanto, só houve diferenças na acumulação de solutos osmóticos entre os híbridos, quanto ao teor de aminoácidos no DINA 10 submetido aos dois ciclos, no segundo ciclo. Contudo, o IAC 8222 manteve o seu psihf alto, podendo ter promovido um ajuste do coeficiente de extensibilidade de parede, que foi acentuado com o endurecimento.A study was conducted to evaluate the water relations of two corn (Zea mays L. hybrids in a greenhouse experiment: IAC 8222 (hybrid adapted to environmental stress and DINA 10 (common hybrid, under one or two cycles of water stress applied at 30 and 46 days after sowing. During the first water deficit cycle, and at the second cycle for plants submitted to both cycles, the leaf water potential (psihf of IAC 8222 was higher than the psihf of DINA 10, at the 6th and last day of water stress, with no difference for the relative water content (CHR between the hybrids. The soluble sugars and amino acids accumulated during the water stress, but no

  17. Parametric decay instability near the upper hybrid resonance in magnetically confined fusion plasmas

    DEFF Research Database (Denmark)

    Hansen, Søren Kjer; Nielsen, Stefan Kragh; Salewski, Mirko

    2017-01-01

    In this paper we investigate parametric decay of an electromagnetic pump wave into two electrostatic daughter waves, particularly an X-mode pump wave decaying into a warm upper hybrid wave (a limit of an electron Bernstein wave) and a warm lower hybrid wave. We describe the general theory...

  18. High-Order Hybridized Discontinuous Galerkin (HDG) Method for Wave Propagation Simulation in Complex Geophysical Media - Elastic, Acoustic and Hydro-Acoustic - an Unifying Framework to Couple Continuous Spectral Element and Discontinuous Galerkin Methods.

    Science.gov (United States)

    Sébastien, T.; Vilotte, J. P.; Guillot, L.; Mariotti, C.

    2014-12-01

    Today seismological observation systems combine broadband seismic receivers, hydrophones and micro-barometers antenna that provide complementary observations of source-radiated waves in heterogeneous and complex geophysical media. Exploiting these observations requires accurate and multi-physics - elastic, hydro-acoustic, infrasonic - wave simulation methods. A popular approach is the Spectral Element Method (SEM) (Chaljub et al, 2006) which is high-order accurate (low dispersion error), very flexible to parallelization and computationally attractive due to efficient sum factorization technique and diagonal mass matrix. However SEMs suffer from lack of flexibility in handling complex geometry and multi-physics wave propagation. High-order Discontinuous Galerkin Methods (DGMs), i.e. Dumbser et al (2006), Etienne et al. (2010), Wilcox et al (2010), are recent alternatives that can handle complex geometry, space-and-time adaptativity, and allow efficient multi-physics wave coupling at interfaces. However, DGMs are more memory demanding and less computationally attractive than SEMs, especially when explicit time stepping is used. We propose a new class of higher-order Hybridized Discontinuous Galerkin Spectral Elements (HDGSEM) methods for spatial discretization of wave equations, following the unifying framework for hybridization of Cockburn et al (2009) and Nguyen et al (2011), which allows for a single implementation of conforming and non-conforming SEMs. When used with energy conserving explicit time integration schemes, HDGSEM is flexible to handle complex geometry, computationally attractive and has significantly less degrees of freedom than classical DGMs, i.e., the only coupled unknowns are the single-valued numerical traces of the velocity field on the element's faces. The formulation can be extended to model fractional energy loss at interfaces between elastic, acoustic and hydro-acoustic media. Accuracy and performance of the HDGSEM are illustrated and

  19. Characterization of <em>Erysiphe necatorem>-Responsive Genes in Chinese Wild <em>Vitis> <em>quinquangularis>

    Directory of Open Access Journals (Sweden)

    Xiping Wang

    2012-09-01

    Full Text Available Powdery mildew (PM, caused by fungus <em>Erysiphe necatorem>, is one of the most devastating diseases of grapevine. To better understand grapevine-PM interaction and provide candidate resources for grapevine breeding, a suppression subtractive hybridization (SSH cDNA library was constructed from <em>E. necatorem>-infected leaves of a resistant Chinese wild <em>Vitis quinquangularisem> clone “Shang-24”. A total of 492 high quality expressed sequence tags (ESTs were obtained and assembled into 266 unigenes. Gene ontology (GO analysis indicated that 188 unigenes could be assigned with at least one GO term in the biological process category, and 176 in the molecular function category. Sequence analysis showed that a large number of these genes were homologous to those involved in defense responses. Genes involved in metabolism, photosynthesis, transport and signal transduction were also enriched in the library. Expression analysis of 13 selected genes by qRT-PCR revealed that most were induced more quickly and intensely in the resistant material “Shang-24” than in the sensitive <em>V. pseudoreticulata em>clone “Hunan-1” by<em> E. necatorem> infection. The ESTs reported here provide new clues to understand the disease-resistance mechanism in Chinese wild grapevine species and may enable us to investigate <em>E. necatorem>-responsive genes involved in PM resistance in grapevine germplasm.

  20. High-order Hybridized Discontinuous Galerkin (HDG) method for wave propagation simulation in complex geophysical media (elastic, acoustic and hydro-acoustic); an unifying framework to couple continuous Spectral Element and Discontinuous Galerkin Methods

    Science.gov (United States)

    Terrana, Sebastien; Vilotte, Jean-Pierre; Guillot, Laurent; Mariotti, Christian

    2015-04-01

    Today seismological observation systems combine broadband seismic receivers, hydrophones and micro-barometers antenna that provide complementary observations of source-radiated waves in heterogeneous and complex geophysical media. Exploiting these observations requires accurate and multi-physics - elastic, hydro-acoustic, infrasonic - wave simulation methods. A popular approach is the Spectral Element Method (SEM) (Chaljub et al, 2006) which is high-order accurate (low dispersion error), very flexible to parallelization and computationally attractive due to efficient sum factorization technique and diagonal mass matrix. However SEMs suffer from lack of flexibility in handling complex geometry and multi-physics wave propagation. High-order Discontinuous Galerkin Methods (DGMs), i.e. Dumbser et al (2006), Etienne et al. (2010), Wilcox et al (2010), are recent alternatives that can handle complex geometry, space-and-time adaptativity, and allow efficient multi-physics wave coupling at interfaces. However, DGMs are more memory demanding and less computationally attractive than SEMs, especially when explicit time stepping is used. We propose a new class of higher-order Hybridized Discontinuous Galerkin Spectral Elements (HDGSEM) methods for spatial discretization of wave equations, following the unifying framework for hybridization of Cockburn et al (2009) and Nguyen et al (2011), which allows for a single implementation of conforming and non-conforming SEMs. When used with energy conserving explicit time integration schemes, HDGSEM is flexible to handle complex geometry, computationally attractive and has significantly less degrees of freedom than classical DGMs, i.e., the only coupled unknowns are the single-valued numerical traces of the velocity field on the element's faces. The formulation can be extended to model fractional energy loss at interfaces between elastic, acoustic and hydro-acoustic media. Accuracy and performance of the HDGSEM are illustrated and

  1. A modulating effect of Tropical Instability Wave (TIW)-induced surface wind feedback in a hybrid coupled model of the tropical Pacific

    Science.gov (United States)

    Zhang, Rong-Hua

    2016-10-01

    Tropical Instability Waves (TIWs) and the El Niño-Southern Oscillation (ENSO) are two air-sea coupling phenomena that are prominent in the tropical Pacific, occurring at vastly different space-time scales. It has been challenging to adequately represent both of these processes within a large-scale coupled climate model, which has led to a poor understanding of the interactions between TIW-induced feedback and ENSO. In this study, a novel modeling system was developed that allows representation of TIW-scale air-sea coupling and its interaction with ENSO. Satellite data were first used to derive an empirical model for TIW-induced sea surface wind stress perturbations (τTIW). The model was then embedded in a basin-wide hybrid-coupled model (HCM) of the tropical Pacific. Because τTIW were internally determined from TIW-scale sea surface temperatures (SSTTIW) simulated in the ocean model, the wind-SST coupling at TIW scales was interactively represented within the large-scale coupled model. Because the τTIW-SSTTIW coupling part of the model can be turned on or off in the HCM simulations, the related TIW wind feedback effects can be isolated and examined in a straightforward way. Then, the TIW-scale wind feedback effects on the large-scale mean ocean state and interannual variability in the tropical Pacific were investigated based on this embedded system. The interactively represented TIW-scale wind forcing exerted an asymmetric influence on SSTs in the HCM, characterized by a mean-state cooling and by a positive feedback on interannual variability, acting to enhance ENSO amplitude. Roughly speaking, the feedback tends to increase interannual SST variability by approximately 9%. Additionally, there is a tendency for TIW wind to have an effect on the phase transition during ENSO evolution, with slightly shortened interannual oscillation periods. Additional sensitivity experiments were performed to elucidate the details of TIW wind effects on SST evolution during ENSO

  2. Valor nutritivo do colmo de híbridos de milho colhidos em três estádios de maturidade Stalk nutritive value of corn hybrids harvested at three maturity stages

    Directory of Open Access Journals (Sweden)

    Diego Reynaga Salazar

    2010-07-01

    Full Text Available O objetivo deste trabalho foi avaliar o efeito da maturidade da planta sobre a qualidade nutricional do colmo de híbridos de milho, para definir critérios de seleção em programas de melhoramento de milho para ensilagem. Foram avaliados 15 híbridos de milho, do programa de melhoramento do Instituto Agronômico, em Campinas, SP, colhidos com 90, 120 e 150 dias após a germinação, em experimento com delineamento de blocos ao acaso, com três repetições. O quarto e o quinto internódios do colmo foram retirados para determinação da composição bromatológica e digestibilidade in vitro. Com o avanço da maturidade, houve queda no teor de fibra e aumento no de lignina de ambos os internódios. Observou-se aumento na digestibilidade da matéria seca do quinto internódio, mas não houve mudanças na do quarto internódio. A maturidade também reduziu a digestibilidade da fibra em detergente neutro (DIVFDN do quarto internódio, mas não a do quinto. A DIVFDN do quarto internódio pode ser utilizada como parâmetro de seleção para aumento da qualidade nutricional de híbridos de milho. Nas três idades de corte, houve grande variabilidade genética dos parâmetros de qualidade, o que realça a possibilidade de implantação de programas de melhoramento genético para qualidade nutricional do milho para ensilagem.The objective of this work was to evaluate the effect of plant maturing on the stalk nutritional quality of corn hybrids, in order to define selection criteria in breeding programs of maize for silage. Fifteen hybrids from the Instituto Agronômico breeding program in Campinas, SP, Brazil, harvested at 90, 120 and 150 days after germination, were evaluated in a randomized block design, with three replicates. The fourth and fifth stalk internodes were removed for determination of chemical composition and in vitro digestibility. In both internodes, fiber content decreased and lignin content increased as maturity advanced. Dry matter

  3. CONTAMINAÇÃO POR AFLATOXINAS EM HÍBRIDOS DE MILHO CULTIVADOS EM TRÊS REGIÕES DO ESTADO DE GOIÁS AFLATOXINS CONTAMINATION OF CORN HYBRIDS IN THREE REGIONS OF THE GOIÁS STATE, BRAZIL

    Directory of Open Access Journals (Sweden)

    Robson Maia Geraldine

    2008-06-01

    ="JUSTIFY">The natural occurrence of aflatoxins B1 (AFB1, B2 (AFB2, G1(AFG1, and G2 (AFG2 in corn grains was evaluated in three locations of Goiás State (Jataí, Montividiu and Goiânia, from twelve grain samples of hybrids (DAS766, DAS657, 30K75, 30F44, 30P70, 30F33, AG7000, DKB350, AG1051, Strike, Speed and Fort. The aflatoxins were analyzed by high performance liquid chromatography (HPLC. The results were related to the temperature and rainfall data from each region, and to the presence of fungi and rotten ears in the samples. The lowest percentage of rotten ears occurred in Goiânia, with a significant difference among the hybrids. The pathological analysis of the seeds was determined by the "Blotter" test. The <em>Aspergillus em>spp. was present in all the samples from Jataí, in 41.7% of the samples from Goiânia, and a single sample from Montividiu. The aflatoxin contamination was higher in the samples from Jataí, followed by Goiânia and Montividiu, respectively. In Jataí, that result was correlated with higher rainfall levels during harvest. The levels of AFB1 ranged between "not detected" (nd and 277.8 µg.kg-1; 0.7 µg.kg-1, and 14 µg.kg-1, for AFB2; and between nd and 34.1 µg.kg-1, for AFG2. The AFG1 was not detected in any of the samples.

    KEY-WORDS: Rotten ear; <em>Aspergillus em>spp.; aflatoxin; maize; HPLC.

  4. Os efeitos da idade na percepção visual de grades senoidais em luminância baixa The effects of age on visual perception of sine-wave gratings at low luminance

    Directory of Open Access Journals (Sweden)

    Natanael Antonio dos Santos

    2006-01-01

    Full Text Available O objetivo deste trabalho foi investigar a função de sensibilidade ao contraste (FSC de adultos e idosos (20-23, 30-39, 40-49, 50-59, 60-69 anos para grades senoidais de 0,25 a 2 cpg em luminância baixa. Todos os participantes apresentavam acuidade visual normal e se encontravam livres de doenças oculares identificáveis. Foram estimados limiares de contraste para 30 participantes (seis em cada faixa etária utilizando o método psicofísico da escolha forçada. Neste método, os participantes tinham que escolher um estímulo contendo uma freqüência de teste (grade senoidal em baixo contraste ou um estímulo neutro com luminância média de 0,7 cd/m². Os resultados mostraram que os grupos de 50-59 e 60-69 anos apresentaram prejuízos significativos na FSC nas freqüências espaciais de 1 e 2 cpg comparados ao grupo de 20-23 anos. Estes resultados sugerem alterações relacionadas à idade na FSC de freqüências espaciais em níveis baixos de luminância.The aim of this work was to investigate the contrast sensitivity function for sine-wave gratings in the range between 0.25-2 cpd in young and older adults (20-23, 30-39, 40-49, 50-59, 60-69 years old using low luminance. All subjects were free from identifiable ocular disease and had normal acuity. We measured the contrast thresholds for 30 participants (six volunteers in each age using the psychophysical forced-choice staircase method. In this method the volunteers had to choose the stimulus containing a test frequency at low contrast (e.g., a sine-wave grating, or another neutral stimulus at mean luminance (0.7 cd/m². The results showed significant changes of CSF for sine-wave gratings at 1 and 2 cpd for the adults 50-59 and 60-69 years old compared to the adults of 20-23 years old. These results suggest age-related changes in the CSF for sine-wave grating at low luminance levels.

  5. Inglês e globalização em uma epistemologia de fronteira: ideologia lingüística para tempos híbridos English and globalization through a border epistemology: linguistic ideology for hybrid times

    Directory of Open Access Journals (Sweden)

    Luiz Paulo da Moita Lopes

    2008-01-01

    Full Text Available Este artigo focaliza o fenômeno do inglês como língua que colabora na construção da globalização, seguindo os princípios de uma epistemologia de fronteira. Tem o objetivo de contribuir na elaboração de uma ideologia lingüística para os tempos híbridos em que vivemos. Baseia-se em uma teorização assentada nos construtos de Império, histórias locais e performatividade, possibilitando uma redescrição da relação entre inglês e globalização. O inglês é compreendido então como língua de fronteira por meio da qual as pessoas se apropriam de discursos globais e reinventam a vida local em suas performances cotidianas. São analisados exemplos de tais usos do inglês em e-mails translingüísticos e no rap brasileiro. Ao concluir, usa-se uma lógica que reconhece tanto o papel imperial do inglês assim como o seu uso transimperial, que possibilita a reinvenção da vida local não como mímica de designs globais, mas como possibilidade de construir uma outra globalização, anti-hegemônica, em performances lingüísticoidentitárias inovadoras nos fluxos da fronteira.This paper focuses on English as a language which helps to construct globalization, following principles of a border epistemology. It aims at contributing to the elaboration of a linguistic ideology for the hybrid times in which we live. It is based on a theorization informed by the constructs of Empire, local histories and performativity, making it possible to re-describe the relationship between English and globalization. English is then understood as a border language through which people appropriate global discourses and re-invent local life in their everyday performances. Examples of such uses of English in translinguistic e-mails and in the Brazilian rap are analyzed. By way of conclusion, it is used a logic which acknowledges both the imperial role of English and its transimperial use, which may re-invent local life not as mimicry of global designs, but as

  6. Herança da tolerância ao alumínio em populações híbridas de trigo Inheritance of aluminum tolerance in wheat hybrid populations

    Directory of Open Access Journals (Sweden)

    CARLOS EDUARDO DE OLIVEIRA CAMARGO

    2000-03-01

    Full Text Available Plântulas originárias de populações híbridas, em geração F2, de 26 cruzamentos entre cultivares de trigo tolerantes (BH-1146, IAC-227, IAC-24, IAC-60, C-3, IAC-5, IAC-18 e IAC-21 e sensíveis (Anahuac 75, IAC-287, IAC-289, Siete Cerros e Veery "S" à toxicidade de alumínio e de 18 cruzamentos entre cultivares tolerantes (BH-1146, IAC-227, IAC-24, IAC-60, C-3, IAC-5, IAC-21, C-17, IAC-74 e IAC-18 foram avaliadas em relação à tolerância a 3 mg/L de Al3+, empregando soluções nutritivas. A tolerância à toxicidade de alumínio foi medida pela capacidade de crescimento da raiz primária central em solução nutritiva completa, após um tratamento de 48 horas em solução contendo 3 mg/L de Al3+. Avaliando-se as plântulas das populações F2 provindas de cruzamentos entre cultivares tolerantes e sensíveis, verificou-se que a tolerância à toxicidade de Al3+ foi dominante, e que em 24 dos cruzamentos, as cultivares tolerantes diferiram das sensíveis por um par de genes. Não foi detectada diferença entre as cultivares tolerantes em relação ao par de genes dominantes em relação à tolerância. Qualquer uma dessas cultivares poderá ser utilizada como fonte de tolerância num programa de cruzamentos em que essa característica for desejada.Seedlings originated from hybrid populations, in F2 generation, from 26 crosses between tolerant wheat cultivars (BH-1146, IAC-227, IAC-24, IAC-60, C-3, IAC-5, IAC-18 and IAC-21 and sensitive cultivars (Anahuac 75, IAC-287, IAC-289, Siete Cerros and Veery "S" to aluminum toxicity and from 18 crosses between tolerant cultivars (BH-1146, IAC-227, IAC-24, IAC-60, C-3, IAC-5, IAC-21, C-17, IAC-74 and IAC-18 were evaluated for tolerance to 3 mg/L of Al3+, using nutrient solutions. It was considered tolerant the plant that was able to show root regrowth of the central primary root in the complete nutrient solution after a treatment of 48 hours in solution containing 3 mg/L of Al3+. The evaluation of

  7. Melhoramento genético da cana-de-açúcar: avaliação de clones provenientes de hibridações efetuadas em 1965 Sugarcane breeding: performance of iac sugarcane clones originated from hybridation

    Directory of Open Access Journals (Sweden)

    Raphael Alvarez

    1987-01-01

    Full Text Available Objetivando estudar dezoito clones de cana-de-açúcar provenientes de hibridações efetuadas em Ubatuba, SP, em 1965, tendo como padrão as variedades comerciais NA56-79 e CB41-76, efetuou-se um experimento em latossolo roxo na Usina Santa Lydia, em Ribeirão Preto, SP. No ensaio, plantado em março de 1973, utilizou-se o delineamento em blocos casualizados com quatro repetições, sendo a análise estatística feita com a média das três colheitas (cana-planta, soca e ressoca. Avaliou-se a produção agrícola, teor de açúcar provável e produtividade de açúcar provável. O clone IAC65-55 apresentou produtividade de açúcar significativamente superior ao padrão CB41-76, enquanto os clones IAC65-220, IAC65-257, IAC65-255, IAC65-155 e IAC65-113 não diferiram significativamente dele. Nenhum desses clones diferiu da variedade NA56-79 em produtividade de açúcar. Em função dessas características, associadas à resistência ao "carvão", os clones IAC65-55, IAC65-257, IAC65-113, IAC65-155 e IAC65-255 poderão constituir alternativas para o cultivo na região de Ribeirão Preto.A group of 18 of the best sugarcane clones obtained from hybridation in 1965, at the Experimental Station of Ubatuba, Instituto Agronômico, were evaluated in one experiment carried out in Santa Lydia mill, Ribeirão Preto, State of São Paulo, Brazil. In 1973, it was started a field trial using as controls the commercial varieties NA56-79, and CB41-76. The experiment design was a randomized complete block with four replications. The cane yield (t/ha, sugar content (kg/t cane, and sugar yield (t/ha were expressed as the average of three harvests: cane plant (18 months, first ratoon (12 months after and second ratoon (12 months after. According to these characteristics the clones IAC65-55, IAC65-257, IAC65-113, IAC65-155 and IAC65-255 were selected, and constitute alternatives of new varieties for the sugarcane cropping in the region of Ribeirão Preto.

  8. Development of CIP/graphite composite additives for electromagnetic wave absorption applications

    Science.gov (United States)

    Woo, Soobin; Yoo, Chan-Sei; Kim, Hwijun; Lee, Mijung; Quevedo-Lopez, Manuel; Choi, Hyunjoo

    2017-09-01

    In this study, the electromagnetic (EM) wave absorption ability of carbonyl iron powder (CIP)/graphite composites produced by ball milling were studied in a range of 28.5 GHz to examine the effects of the morphology and volume fraction of graphite on EM wave absorption ability. The results indicated that a ball milling technique was effective in exfoliating the graphite and covering it with CIP, thereby markedly increasing the specific surface area of the hybrid powder. The increase in the surface area and hybridization with dielectric loss materials (i.e., graphite) improved EM absorbing properties of CIP in the range of S and X bands. Specifically, the CIP/graphite composite containing 3 wt% graphite exhibited electromagnetic wave absorption of -13 dB at 7 GHz, -21 dB at 5.8 GHz, and -29 dB at 4.3 GHz after 1 h, 8 h, and 16 h of milling, respectively. [Figure not available: see fulltext.

  9. Avaliação e seleção de híbridos de cacaueiro em Rondônia Evaluation and selection of cacao hybrids in Rondônia

    Directory of Open Access Journals (Sweden)

    Claudio Guilherme Portela de Carvalho

    2001-08-01

    Full Text Available Este trabalho teve como objetivo avaliar e selecionar híbridos de cacaueiro, quanto a rendimento e qualidade de sementes, nas condições ecológicas do Município de Ouro Preto do Oeste, Rondônia. A seleção foi feita comparando-se, pelo teste de Duncan, as médias das medidas dos componentes de rendimento avaliados em um ensaio conduzido entre 1986 e 1991. O delineamento experimental usado foi o de blocos completos casualizados. Os melhores desempenhos, quanto aos caracteres avaliados, foram obtidos em cruzamentos que incluíram os clones POUND 7 e BE 10 (número total de frutos coletados, SCA 6 e PA 150 (número total de frutos sadios, PA 150 (peso total de sementes úmidas, IMC 67 e POUND 7 (peso médio de sementes úmidas por fruto. Na análise simultânea dos caracteres, os híbridos SCA 6 x ICS 1, PA 150 x SIC 328 e IMC 67 x BE 8 sobressaíram-se, em relação aos demais.The goal of the present work was to evaluate and to select cacao hybrids with respect to seed yield and quality for ecological conditions of municipality of Ouro Preto do Oeste, Rondônia, Brazil. The selection was done comparing, by means of Duncan test, the yield measurement average in trial conducted from 1986 to 1991. A randomized complete block design was used. The best performance, considering total number of collected fruits, total number of healthy fruits, total weight of humid seeds and mean weight of humid seeds per fruit, were obtained from crosses involving POUND 7 and BE 10, SCA 6 and PA 150, PA 150, IMC 67 and POUND 7 clones, respectively. The hybrids SCA 6 x ICS 1, PA 150 x SIC 328 and IMC 67 x BE 8 were outstanding when compared to the others.

  10. Composição bromatológica de silagens de híbridos de sorgo cultivados em diferentes densidades de plantas Chemical composition of silage sorghum hybrids grown at different densities

    Directory of Open Access Journals (Sweden)

    Poliana Mendes Avelino

    2011-03-01

    Full Text Available Avaliou-se a composição bromatológica das silagens de dois híbridos de sorgo, AG-2005 (duplo propósito e VOLUMAX (forrageiro, cultivados nos espaçamentos de 0,50; 0,75 e 1,00 m, resultando nas densidades de 140.000; 186.666 e 280.000 plantas por ha, respectivamente. A silagem do híbrido AG-2005 apresentou matéria seca (MS superior no espaçamento de 1,00 m e foi mais elevada ao da silagem de VOLUMAX em todos os espaçamentos. A proteína bruta (PB elevou-se com a redução dos espaçamentos (6,6; 6,8 e 8%, respectivamente, com maior valor médio no AG-2005 (7,7 vs 6,5%. A fibra em detergente neutro (FDN foi menor no AG-2005 (59,25 vs 62,3% e no espaçamento 0,75 m. Para fibra em detergente ácido (FDA ocorreu diferença entre os dois híbridos no espaçamento 0,5 m, sendo de 33,5 e 39,3 %, respectivamente, para o AG-2005 e VOLUMAX. O EE apresentou diferença significativa (P The objective of the experiment was to evaluate the nutritive value of silages from two sorghum hybrids, AG-2005 (double purpose and VOLUMAX (forage cultivated with different row spacings (0.50 m; 0.75 m and 1.00 m, resulting in 140,000; 186,666 e 280,000 plants per ha, respectively. Dry matter content of AG-2005 silage was higher for 1 m row spacing, and was higher than for VOLUMAX silage in all row spacings. Crude protein increased as the row spacing was reduced (6.6; 6.8 and 8%, respectively, with higher average value for AG-2005 (7.7 vs 6.5%. Neutral detergent fiber was lower for AG-2005 (59.25 vs 62.3% and for .75 m spacing. Acid detergent fiber differed between hybrids in .5 m row spacing, being 33.5 and 39.3%, respectively, for AG-2005 and VOLUMAX. Ether extract was significantly different between hybrids in .5 m row spacing, being higher for AG-2005 (2.05 vs 1.61%. The use of AG-2005 is recommended for silage production due to its better qualitative characteristics than the VOLUMAX. The .5 m row spacing is recommended for both hybrids, since it improves the

  11. A Study of the Strategic Alliance for EMS Industry: The Application of a Hybrid DEA and GM (1, 1 Approach

    Directory of Open Access Journals (Sweden)

    Chia Nan Wang

    2015-01-01

    Full Text Available Choosing a partner is a critical factor for success in international strategic alliances, although criteria for partner selection vary between developed and transitional markets. This study aims to develop effective methods to assist enterprise to measure the firms’ operation efficiency, find out the candidate priority under several different inputs and outputs, and forecast the values of those variables in the future. The methodologies are constructed by the concepts of Data Envelopment Analysis (DEA and grey model (GM. Realistic data in four consecutive years (2009–2012 a total of 20 companies of the Electronic Manufacturing Service (EMS industry that went public are completely collected. This paper tries to help target company—DMU1—to find the right alliance partners. By our proposed approach, the results show the priority in the recent years. The research study is hopefully of interest to managers who are in manufacturing industry in general and EMS enterprises in particular.

  12. Capacidade combinatória entre híbridos simples de milho em dialelo circulante Combining ability in corn single-cross hybrids by circulant diallel

    OpenAIRE

    Alessandra Zawadzki Pfann; Marcos Ventura Faria; Alex Antônio de Andrade; Ildon Rodrigues do Nascimento; Cacilda Márcia Duarte Rios Faria; Roni Maikel Bringhentti

    2009-01-01

    Onze híbridos comerciais de milho (AS 1550, DKB 214, DKB 215, DKB 330, Dow 2B150, Dow 8460, P 30F33, P 30F53, P 30P70, Penta e Premium Flex) foram intercruzados, obtendo-se 44 híbridos duplos, segundo um dialelo circulante com p=11 (onze genitores) e s=8 (intercruzados 8 a 8), avaliado em delineamento em blocos casualizados com três repetições. Foram conduzidos dois experimentos na Região Centro-sul do Paraná, nos municípios de Guarapuava e Goioxim. Os dados referentes à produção de grãos, al...

  13. Wave and plasma measurements and GPS diagnostics of the main ionospheric trough as a hybrid method used for Space Weather purposes

    Directory of Open Access Journals (Sweden)

    H. Rothkaehl

    2008-02-01

    Full Text Available The region of the main ionospheric trough is a unique region of the ionosphere, where different types of waves and instabilities can be generated. This region of the ionosphere acts like a lens, focusing a variety of indicators from the equator of plasmapause and local ionospheric plasma. This paper reports the results of monitoring the mid-latitude trough structure, dynamics and wave activity. For these purposes, the data gathered by the currently-operating DEMETER satellite and past diagnostics located on IK-19, Apex, and MAGION-3 spacecraft, as well as TEC measurements were used. A global-time varying picture of the ionospheric trough was reconstructed using the sequence of wave spectra registered and plasma measurements in the top-side ionosphere. The authors present the wave activity from ULF frequency band to the HF frequency detected inside the trough region and discuss its properties during geomagnetic disturbances. It is thought that broadband emissions are correlated with low frequency radiation, which is excited by the wave-particle interaction in the equatorial plasmapause and moves to the ionosphere along the geomagnetic field line. In the ionosphere, the suprathermal electrons can interact with these electrostatic waves and excite electron acoustic waves or HF longitudinal plasma waves.

    Furthermore, the electron density trough can provide useful data on the magnetosphere ionosphere dynamics and morphology and, in consequence, can be used for Space Weather purposes.

  14. 短波射线追踪技术中的电离层混合建模方法%Ionosphere hybrid modeling method for short-wave ray tracing

    Institute of Scientific and Technical Information of China (English)

    栗伟珉; 苏东林; 阎照文; 刘焱

    2012-01-01

    在国际参考电离层模型和多层准抛物模型的基础上,提出了一种混合应用两种模型进行电离层建模的新方法.利用射线追踪技术,分别对混合模型和传统国际参考电离层模型下短波射线在电离层中的轨迹进行了仿真,得到了电波群路径.通过与实测电波群路径的对比,结果表明:对中国中纬度地区在电离层混合模型下的射线追踪精度优于传统国际参考电离层模型下的射线追踪精度,同时混合建模方法降低了多层准抛物模型对输入条件的要求,扩展了多层准抛物模型在射线追踪技术中的应用范围.%Based on the international reference ionosphere(IRI) and the quasi-parabolic segments(QPS) model,a new ionosphere hybrid modeling method for short-wave ray tracing was proposed.The group ranges which show the short-wave propagation trace in the ionosphere were obtained separately by simulation in the hybrid model and the IRI model.By comparing the simulated results and the ionospheric oblique incidence sounding experimental data,the hybrid modeling method accuracy at mid-latitude region in China was analyzed.It indicates the ray tracing simulation accuracy in the hybrid model on experimental day better than the one in the IRI model.The limit to the QPS model's input is reduced by the hybrid modeling method and the QPS model's application range is extended in ray tracing technology.

  15. Phosphorus absorption by of corn hybrids grown in savana soils; Absorcao de fosforo por hibridos de milho cultivados em solo de cerrado

    Energy Technology Data Exchange (ETDEWEB)

    Fernandes, Cristiano [Fazenda Amazonas, Serra Azul, SP (Brazil); Muraoka, Takashi [Centro de Energia Nuclear na Agricultura (CENA), Piracicaba, SP (Brazil)

    2002-12-01

    In the past years the savana region has been one of the main agricultural expansion areas, however their soils present high limitation for plant growth due their high acidity, low natural fertility, and low phosphorus availability. The objective of this work was to compare 30 of the main recommended maize (Zea mays L.) hybrids for the cerrado region in relation to their ability to absorb poorly-available soil phosphorus through the {sup 32}P isotopic dilution technique, using a Typic Dystrarox cultivated for 20 years and another under natural vegetation. Differences in absorption ability were observed among hybrids, seven classified as efficient, sixteen mildly efficient and seven inefficient, for the case of soil cultivated for 20 years. The plant growth and phosphorus concentration in the natural soil was lower due to its low fertility. (author)

  16. In vitro growth of Brassocattleya orchid hybrid in different concentrations of KNO3, NH4NO3 and benzylaminopurine Cultivo in vitro de Brassocattleya (Orchidaceae em diferentes concentrações de KNO3, NH4NO3 e benzilaminopurina

    Directory of Open Access Journals (Sweden)

    Jean C Cardoso

    2011-09-01

    Full Text Available One of the most important applications of plant tissue culture is mass propagation of ornamental plants. This experiment evaluated the effect of different concentrations of NH4NO3 and KNO3 and BAP on the in vitro growth of orchid hybrid Brassocattleya 'Pastoral'. Seedlings of this orchid hybrid were used as explants and cultivated in medium with mineral salts and vitamins from the MS medium (Murashige & Skoog, 1962, with the macronutrients P, Ca and Mg reduced by half, and with an addition of 25 g L-1 of sucrose, 0.1 g L-1 of myo-inositol and 1.5 g L-1 of activated charcoal. Agar-agar was added (6.5 g L-1 and the pH was adjusted to 5.8. As treatments, four concentrations of the NH4NO3 and KNO3 (2x; 1x; ½ and ¼ MS medium and three concentrations of BAP (0.0; 0.5 and 1.0 mg L-1 were assayed. The multiplication, growth in height, fresh and dry weight and sugar level in dry weight of sprouts were evaluated. There occurred a higher growth in height with 0.25x NH4NO3 and KNO3 salts concentrations of MS medium and higher rate of multiplication with combination of NH4NO3 and KNO3 reduced by half of the MS medium concentration and 1.0 mg L-1 BAP.Entre as maiores aplicações da cultura de tecidos de plantas está a propagação massal de mudas de plantas ornamentais. O objetivo deste trabalho foi avaliar o cultivo in vitro de um híbrido de orquídea Brassocattleya em diferentes concentrações de NH4NO3, KNO3 e BAP. Foram utilizadas sementes do híbrido de orquídea Brassocattleya 'Pastoral' e as plantas foram cultivadas em meio MS com redução pela metade das fontes de P, Mg e Ca e adição de 25 g L-1 de sacarose, 100 mg L-1 de mio-inositol, 1,5 g L-1 de carvão ativo e 6,5 g L-1 de ágar-ágar, sendo o pH ajustado para 5,8. Como tratamentos foram usados quatro concentrações dos sais NH4NO3 e KNO3 (2x; 1x; ½ e ¼ do meio MS e três concentrações de BAP (0,0; 0,5 e 1,0 mg L-1. Avaliou-se a multiplicação, o crescimento em altura, massa fresca

  17. Resposta de híbridos de milho irrigado à densidade de plantas em três épocas de semeadura Response of irrigated corn hybrids to plant density in three sowing dates

    Directory of Open Access Journals (Sweden)

    Paulo Regis Ferreira da Silva

    1999-04-01

    Full Text Available A determinação da densidade ótima de semeadura do milho, além de ser influenciada pelas características dos híbridos, pelo nível de fertilidade do solo e pela disponibilidade hídrica, pode também variar de acordo com a época da semeadura, uma vez que ela afeta o crescimento e desenvolvimento da planta. Com o objetivo de determinar a densidade ótima de planta em híbridos de milho com elevado potencial de rendimento de grãos, em três épocas de semeadura, com relação a rendimento de grãos, componentes do rendimento e outras características agronômicas, foram feitos quatro experimentos na região fisiográfica da Depressão Central do Rio Grande do Sul, município de Eldorado do Sul, com suplementação hídrica por aspersão. Os tratamentos constaram de quatro híbridos (Pioneer 3063, Pioneer 3207, XL 212 e Cargill 901, quatro densidades de plantas (50, 70, 90 e 110.000 pl/ha e de três épocas de semeadura (agosto, outubro e dezembro. Não há resposta à densidade de plantas dos híbridos de milho testados nas épocas de semeadura de agosto e dezembro. O aumento na densidade de plantas somente foi vantajosa na semeadura de outubro, quando se obtiveram maiores rendimentos de grãos na densidade de 70.000 pl/ha, independentemente do híbrido avaliado, nas duas estações de crescimento.Plant density response of corn besides influenced by hybrids traits, soil fertility level and water availability, could also vary with sowing date, since it affects plant growth and development. With the objective of determining the most adequate plant density of corn hybrids with high potential grain yields, in three sowing dates, in relation to grain yields, yield components and other agronomic traits, four experiments were conducted in the state of Rio Grande do Sul, Brazil, with complementary irrigation. The treatments were composed by four hybrids (Pioneer 3063, Pioneer 3207, XL 212 and Cargill 901, four plant densities (50, 70, 90 and 110

  18. Emergência em campo de híbridos simples de milho superdoce de um cruzamento dialélico Field emergence of supersweet maize single crosses hybrids from a complete diallel cross

    Directory of Open Access Journals (Sweden)

    Margarida Agostinho Lemos

    2002-06-01

    Full Text Available Para identificar híbridos simples de milho superdoce de elevado poder germinativo, foram avaliados em 1996/97, 45 híbridos simples e 10 linhagens S4, originados de cruzamento dialélico completo, nos municípios de Pesqueira e Vitória de Santo Antão (PE. O delineamento utilizado foi "látice"7 x 8 com duas repetições por local. Foram estimados os efeitos da capacidade geral (CGC e específica (CEC de combinação para o caráter. A análise conjunta de variância mostrou alta significância de linhagens, de híbridos e capacidades combinatórias. Houve interação significativa de CGC e CEC (PTo identify single crosses hybrids of supersweet maize of high seed germination in 1996/97, 45 single crosses and 10 inbred lines were evaluated (S4, from a complete diallel cross, at Pesqueira and Vitória de Santo Antão, Brazil. A lattice 7 x 8 design was used with two replications, per each location. The general (GCA and specific (SCA combining ability effects were estimated for the trait stand. In the combined analysis of variance, lines, hybrids and both GCA and SCA effects were significant (P<0.01. The interactions of GCA and SCA (P<0.01 were significant with the locations. For the individual analysis, the mean squares estimates for lines, hybrids, GCA and SCA were also significant (P<0.01. The relative magnitude of GCA and SCA mean squares indicated predominance of additive gene effects. The average mean seed germination were of 40.4% and 56.5% at Pesqueira and Vitória de Santo Antão, respectively. The hybrids L3 x L6 and L3 x L7 at Pesqueira and L1 x L10 and L3 x L5 at Vitória de Santo Antão, were the most favorable single crosses of high quality seed having good field emergence potential.

  19. Produtividade e valor nutricional da silagem de híbridos de milho em diferentes alturas de colheita Productivity and nutritional value of silage of corn hybrids with different heights of harvest

    Directory of Open Access Journals (Sweden)

    F.C.L. Oliveira

    2011-04-01

    Full Text Available Cinco híbridos de milho foram avaliados quanto à produtividade de matéria seca, ao valor nutritivo da silagem e à produtividade de leite. Os híbridos avaliados foram AS 32, AG 9090, CD 308, DKB 747 e P 30F87, colhidos em três alturas de corte: 15, 35 e 55 cm. O delineamento experimental foi em blocos casualizados com parcelas subdivididas e três repetições. Para confecção das silagens, utilizaram-se silos experimentais de PVC com 20 cm de diâmetro e 40 cm de altura. A produtividade de leite, por tonelada de silagem (eficiência alimentar e por hectare, foi estimada pelo modelo Milk2006. A produtividade de forragem ensilável reduziu com o aumento da altura de colheita, com resultados de 14,6; 13,0 e 12,6 t/ha MS para as alturas de colheita de 15 cm, 35 cm e 55 cm, respectivamente. O híbrido de milho e a altura de colheita influenciaram a composição bromatológica das silagens, com exceção do teor de extrato etéreo (EE, que não foi influenciado pela altura de colheita. Ocorreu interação híbrido × altura de colheita para o teor de amido, a digestibilidade in vitro da MS e da fibra em detergente neutro (FDN e o teor de nutrientes digestíveis totais (NDT. Houve efeito da altura de colheita sobre a eficiência alimentar, cujos valores médios foram de 1.226, 1.291 e 1.393 kg leite/t silagem nas alturas de colheita de 15, 35 e 55 cm, respectivamente. Observou-se também efeito do tipo de híbrido sobre a produtividade de leite e a eficiência alimentar, com melhores valores verificados para o híbrido DKB 747 colhido na altura de 55 cm. Ao elevar a altura de colheita, melhora-se o valor nutritivo da silagem sem prejudicar a produtividade de leite por hectare. O manejo da altura de corte não substitui a escolha de melhores híbridos para produção de silagem de alta qualidade e produtividade.Five corn hybrids were evaluated to the productivity of dry matter, nutritive value of silage and milk yield. The hybrids evaluated were

  20. Parametric decay of linearly polarized shear Alfvén waves in oblique propagation: One and two-dimensional hybrid simulations

    National Research Council Canada - National Science Library

    Lorenzo Matteini; Simone Landi; Luca Del Zanna; Marco Velli; Petr Hellinger

    2010-01-01

      The parametric instability of a monochromatic shear Alfvén wave in oblique propagation with respect the ambient magnetic field is investigated in a kinetic regime, performing one-dimensional (1-D...

  1. Avaliação de cultivares e híbridos de bananeira em quatro ciclos de produção Evaluation of banana cultivars and hybrids in four production cycles

    Directory of Open Access Journals (Sweden)

    Sebastião de Oliveira e Silva

    2002-11-01

    Full Text Available Híbridos superiores de bananeira com alta produtividade, frutos vistosos e resistência a doenças estão sendo gerados no programa de melhoramento genético da Embrapa-Centro Nacional de Pesquisa de Mandioca e Fruticultura Tropical. Este trabalho objetivou avaliar alguns desses genótipos em quatro ciclos de produção, visando sua recomendação aos agricultores. O experimento foi realizado em delineamento inteiramente casualizado, com 18 repetições, em Cruz das Almas, BA. Avaliaram-se as cultivares Grande-Naine, Nanica, Nam, Thap Maeo, Mysore, Caipira, Prata-Comum, Pacovan e Prata-Anã e os híbridos Pioneira, PA03-22, FHIA-18, PV03-76, PV03-44 e JV03-15. Analisaram-se os caracteres altura da planta, diâmetro do pseudocaule, peso do cacho, número de frutos, comprimento do fruto e ciclo. Ao longo dos ciclos, a 'Nanica' apresentou o menor porte, enquanto a 'Prata-Anã' se destacou no diâmetro do pseudocaule, seguida pela 'Prata-Comum' e pelo JV03-15. A 'Thap Maeo' sobressaiu-se no peso do cacho e no número de frutos, seguida pelo FHIA-18, no primeiro caráter, e pela 'Mysore', pela 'Caipira' e pelo FHIA-18, no segundo caráter. A 'GrandeNaine' e a 'Nanica' apresentaram o maior comprimento do fruto, enquanto o FHIA-18 e o PA03-22 destacaram-se na precocidade. A 'Thap Maeo' tem potencial para substituir a 'Mysore' e os híbridos avaliados apresentam qualidade para vir a ser recomendados aos agricultores.New productive banana hybrids, presenting good fruits and disease resistant, have been generated at Embrapa-Centro Nacional de Pesquisa de Mandioca e Fruticultura Tropical. The objective of this work was to evaluate some of these genotypes in four production cycles, to recommend them to the farmers. The experiment was carried out in the completely randomized design with 18 replications in Cruz das Almas, BA, Brazil. The genotypes evaluated were the varieties Grande-Naine, Nanica, Nam, Thap Maeo, Mysore, Caipira, Prata-Comum, Pacovan and

  2. Continuous spike-waves during slow waves sleep: a clinical and electroencephalografic study in fifteen children Ponta-onda contínua do sono lento: estudo clínico e eletrencefalográfico em quinze crianças

    Directory of Open Access Journals (Sweden)

    ADRIANA A. F. DJABRAIAN

    1999-09-01

    Full Text Available We report on the clinical and EEG features of 15 patients with the syndrome of "continuous spike waves during slow wave sleep" (CSWSS. The differential diagnosis of CSWSS includes benign epilepsy of childhood with centro-temporal spikes, and Landau-Kleffner and Lennox-Gastaut syndromes. We found normal CT and MRI features in 6 cases, periventricular leukomalacia with and without diffuse brain atrophy in 4 cases and hydrocephalus in 1 case. There was no association between specific neurological findings and CSWSS. Nine of our cases had relatively focal discharges, like some cases from the literature. The occurrence of CSWSS appears to be age-related, generaly between the ages of 5 to 12 years, with a strong temporal relation to the neupsychological deterioration in its nature, severity and prognosis. We believe that this striking disorder has been overlooked and that routine sleep EEG studies on epileptic children may disclose additional cases of CSWSS.Relatamos as características clínicas e eletroencefalográficas de 15 patientes com a síndrome de ponta-onda contínua do sono não-REM (POCSNR. O diagnóstico diferencial da POCSNR inclue a epilepsia benigna da infância com pontas centro-temporais e as síndromes de Landau-Kleffner e Lennox-Gastaut. Encontramos TC e RNM de crânio normais em 6 casos, leucomalácia periventricular em 4 e hidrocefalia em 1. Não houve associação de achados neurológicos específicos e a POCSNR. Nove dos nossos casos tinham descargas relativamente focais, como alguns casos da literatura. A ocorrência da POCSNR parece ser idade-dependente, geralmente entre 5 e 12 anos, com forte relação temporal à deteriorização neurocognitiva, em sua natureza, severidade e prognóstico. Acreditamos que esta síndrome tem sido pouco diagnosticada e que a realização rotineira de EEG em sono em crianças epilépticas possa revelar novos casos de POCSNR.

  3. Heat transfer in hybrid media for laminar flow with recirculation; Transferencia de calor em meios hibridos para escoamentos laminares com recirculacao

    Energy Technology Data Exchange (ETDEWEB)

    Rocamora Junior, Francisco Dias [Centro Tecnico Aeroespacial (CTA-IEAv), Sao Jose dos Campos, SP (Brazil). Inst. de Estudos Avancados. Dept. de Energia Nuclear]. E-mail: rocamora@mec.ita.br; Delemos, Marcelo J.S. [Centro Tecnico Aeroespacial (CTA-IEAv), Sao Jose dos Campos, SP (Brazil). Inst. Tecnologico de Aeronautica. Dept. de Energia]. E-mail: delemos@mec.ita.br

    2000-07-01

    This work presents numerical solutions for flow and heat transfer in hybrid media (clear/porous medium). Laminar flow between parallel plates with recirculation induced by a porous obstacle was considered. The flow governing equations for both clear and porous media were solved using a single computational domain and appropriate interface boundary conditions. The theory proposed by Ochoa-Tapia e Whitaker (1995) was applied for considering the jump conditions at the interface. The influence of several parameters on flow and heat transfer, such as the thermal conductivity ratio, permeability, porosity and fluid superficial velocity, was discussed. (author)

  4. An FMM-FFT accelerated integral equation solver for characterizing electromagnetic wave propagation in mine tunnels and galleries loaded with conductors

    KAUST Repository

    Yücel, Abdulkadir C.

    2014-07-01

    Reliable wireless communication and tracking systems in underground mines are of paramount importance to increase miners\\' productivity while monitoring the environmental conditions and increasing the effectiveness of rescue operations. Key to the design and optimization of such systems are electromagnetic (EM) simulation tools capable of analyzing wave propagation in electromagnetically large mine tunnels and galleries loaded with conducting cables (power, telephone) and mining equipment (trolleys, rails, carts), and potentially partially obstructed by debris from a cave-in. Current tools for simulating EM propagation in mine environments leverage (multi-) modal decompositions (Emslie et. al., IEEE Trans. Antennas Propag., 23, 192-205, 1975; Sun and Akyildiz, IEEE Trans. Commun., 58, 1758-1768, 2010), ray-tracing techniques (Zhang, IEEE Tran. Vehic. Tech., 5, 1308-1314, 2003), or full wave methods. Modal approaches and ray-tracing techniques cannot accurately account for the presence of conductors, intricate details of transmitters/receivers, wall roughness, or unstructured debris from a cave-in. Classical full-wave methods do not suffer from such restrictions. However, they require prohibitively large computational resources when applied to the analysis of electromagnetically large tunnels loaded with conductors. Recently, an efficient hybrid method of moment and transmission line solver has been developed to analyze the EM wave propagation inside tunnels loaded with conductors (Brocker et. al., in Proc IEEE AP-S Symp, pp.1,2, 2012). However, the applicability of the solver is limited to the characterization of EM wave propagation at medium frequency band.

  5. Qualidade e maturação de tangerinas e seus híbridos em São Paulo Quality and maturation of tangerines and their hybrids in São Paulo

    Directory of Open Access Journals (Sweden)

    Simone Rodrigues da Silva

    2009-12-01

    Full Text Available A ampliação da oferta de tangerinas tanto no mercado interno como no externo é limitada pela grande quantidade de sementes nos frutos das principais cultivares, danos na casca resultante de doenças e pela pequena produção nas épocas mais quentes do ano. O presente trabalho teve como objetivo caracterizar a qualidade dos frutos e a época de maturação de 46 tangerinas e híbridos em condições de campo na Estação Experimental de Citricultura de Bebedouro (EECB, Bebedouro-SP. As variedades de tangerinas e híbridos (tangores e tangelos foram introduzidas de bancos de germoplasma da Itália, Portugal, Espanha e França, e a pesquisa desenvolveu-se durante os anos agrícolas de 2001/2002 e 2002/2003. Foram avaliadas características externas de qualidade, como altura e diâmetro dos frutos, massa dos frutos, facilidade em descascar com a mão e características internas como: número de sementes, teor de sólidos solúveis totais, acidez total titulável, rendimento em suco, "ratio" e rendimento em polpa. Duas cultivares apresentaram frutos de boa qualidade e época de maturação precoce, podendo ser disponibilizadas no mercado, num período de escassez deste tipo de citros, e serem alternativas à tangerina-'Cravo'. Quatro cultivares que apresentaram boa qualidade e maturação mediana poderão ser alternativas à 'Poncã'.The extension of tangerine offering both for internal and external markets is limited by the large amount of seeds present in the main cultivars, the occurrence of peel injures caused by diseases and the small fruit production during the hottest periods of the year. This work was aimed to characterize the fruit quality and maturation period of 46 tangerines and hybrids grown in the field at the Estação Experimental de Citricultura de Bebedouro (EECB, located in Bebedouro county, in São Paulo State, Brazil. Tangerines and their hybrids (tangors and tangelos were introduced from germplasm banks of Italy, Portugal

  6. Absorção de fósforo por híbridos de milho cultivados em solo de cerrado Phosphorus absorption by of corn hybrids grown in savana soils

    Directory of Open Access Journals (Sweden)

    Cristiano Fernandes

    2002-12-01

    Full Text Available Nos últimos anos, a região do cerrado tem sido uma das principais áreas de expansão agrícola, porém seus solos apresentam grandes limitações à produção agrícola devido à sua elevada acidez e baixa fertilidade natural, principalmente quanto à disponibilidade de fósforo para as plantas. Este trabalho teve como objetivo comparar 30 híbridos de milho (Zea mays L., recomendados para a região do cerrado, quando a eficiência na absorção do P pouco disponível em solos pobres neste nutriente, através da técnica da Diluição Isotópica de 32P. Foi utilizado um Latossolo Vermelho-Amarelo distrófico sob duas condições de manejo, um cultivado a 20 anos e outro sob vegetação natural. Houve diferença na absorção de P entre os híbridos avaliados em ambos os solos, sendo que no solo natural o acúmulo de P e o desenvolvimento das plantas foi bastante reduzido devido à sua baixa fertilidade. Quanto à eficiência na utilização de P, houve diferença entre os híbridos, sendo que dos 30 híbridos avaliados, 7 foram classificados como eficientes, 16 como medianamente eficientes e 7 ineficientes, quando plantados no solo cultivado há 20 anos.In the past years the savana region has been one of the main agricultural expansion areas, however their soils present high limitation for plant growth due their high acidity, low natural fertility, and low phosphorus availability. The objective of this work was to compare 30 of the main recommended maize (Zea mays L. hybrids for the cerrado region in relation to their ability to absorb poorly-available soil phosphorus through the 32P isotopic dilution technique, using a Typic Dystrarox cultivated for 20 years and another under natural vegetation. Differences in absorption ability were observed among hybrids, seven classified as efficient, sixteen mildly efficient and seven inefficient, for the case of soil cultivated for 20 years. The plant growth and phosphorus concentration in the natural

  7. Radioactive waste transmutation in a fission-fusion hybrid system; Transmutacao de rejeitos radioativos em sistemas hibridos de fusao-fissao

    Energy Technology Data Exchange (ETDEWEB)

    Cabrera, Carlos Eduardo Velasquez

    2015-07-01

    A fission-fusion hybrid reactor is proposed for recycling and transmutation of highly radioactive waste. Two fusion systems were evaluated. A Tokamak, based on magnetic confinement, and another based on inertial confinement. These systems have been modified and designed to place a transmutation layer loaded with transuranic elements from spent fuel of nuclear power plants. The transmutation layer is the first presented in specific literature to be used with fuel reprocessed by the method UREX + and further spiked with depleted uranium or thorium to reduce the amount of fissile material in order to keep a subcritical system. The evaluations were carried out by varying geometric parameters such as the thickness of transmutation layer and the radius of the fuel rod. Depending on the case this variations increase the efficiency to reduce the transuranic contained in the fuel. The results show the possibility of reducing the transuranic for each model and transmutation efficiency compared to the initial amount of recycled fuel for each fusion reactor. Furthermore, a comparison of both hybrid fusion-fission systems is performed in order to find the best system to reduce transuranics efficiently. (author)

  8. Human papillomavirus detection in cervical dysplasias or neoplasias and in condylomata acuminaata by in situ hybridization with biotinylated DNA probes Detecção de papilomavirus humano em displasias ou neoplasias cervicais e em condilomas acuminados por hibridização in situ com sondas de DNA biotiniladas

    Directory of Open Access Journals (Sweden)

    Eliane Machado Guimarães

    1992-08-01

    Full Text Available Specimens from cervical dysplasias or carcinomas and genital condylomata acuminata were retrospectively analysed by in situ hybridization (ISH with bioti-nylated DNA probes for human papillomavirus (HPV types 6, 11, 16 and 18. In the control group no case was positive for HPV DNA. In mild/moderate dysplasias, 4 cases (14% were positive for HPV 6 or 11 and 2 cases (7%, for HPV 16. In the severe dysplasia/in situ carcinoma group, 9 cases (31% showed presence of DNA of HPV types 16 or 18. Six invasive carcinomas (20% were positive for HPV type 16 or 18. Among condylomata acuminata, 22 cases (73% were positive for HPV types 6 or 11. In all ISH-positive cases only one viral type was detected. No correlation between HPV DNA positivity and histological findings of HPV infection was observed. Although less sensitive than some other molecular biology techniques, in situ hybridization with biotinylated DNA probes proved to be simple and useful for detecting and typing HPV in samples routinely received for histopathological analysis.Amostras de displasias ou carcinomas do colo uterino e de condilomas acuminados da região genital foram analisados retrospectivamente por hibridização in situ (HIS com sondas de DNA biotiniladas de papilomavirus humano (HPV tipos 6, 11, 16 e 18. Nenhum caso do grupo controle foi positivo para DNA de HPV. Em displasias leve/moderada, 4 casos (14% foram positivos para HPV 6 ou 11 e 2 casos (7%, para HPV 16. No grupo de displasia acentuada/carcinoma in situ, 9 casos (31% tinham DNA de HPV tipos 16 ou 18. Seis carcinomas invasores (20% foram positivos para HPV tipos 16 ou 18. Entre os condilomas acuminados, 22 casos (73% foram positivos para HPV tipos 6 ou 11. Em todos os casos positivos pela HIS somente um tipo viral foi encontrado. Não foi observada correlação entre a positividade para DNA de HPV e achados histológicos de infecção por HPV. Apesar de menos sensível que algumas outras técnicas de biologia molecular, a

  9. Time-Dependent Damage Investigation of Rock Mass in an <em>In> em>Situ> Experimental Tunnel

    Directory of Open Access Journals (Sweden)

    Jing Chen

    2012-08-01

    Full Text Available In underground tunnels or caverns, time-dependent deformation or failure of rock mass, such as extending cracks, gradual rock falls, <em>etc>., are a costly irritant and a major safety concern if the time-dependent damage of surrounding rock is serious. To understand the damage evolution of rock mass in underground engineering, an <em>in situem> experimental testing was carried out in a large belowground tunnel with a scale of 28.5 m in width, 21 m in height and 352 m in length. The time-dependent damage of rock mass was detected in succession by an ultrasonic wave test after excavation. The testing results showed that the time-dependent damage of rock mass could last a long time, <em>i.e.>, nearly 30 days. Regression analysis of damage factors defined by wave velocity, resulted in the time-dependent evolutional damage equation of rock mass, which corresponded with logarithmic format. A damage viscoelastic-plastic model was developed to describe the exposed time-dependent deterioration of rock mass by field test, such as convergence of time-dependent damage, deterioration of elastic modules and logarithmic format of damage factor. Furthermore, the remedial measures for damaged surrounding rock were discussed based on the measured results and the conception of damage compensation, which provides new clues for underground engineering design.

  10. Vegetative development of orchid hybrid in different substratesDesenvolvimento vegetativo de híbrido de orquídea em diferentes substratos

    Directory of Open Access Journals (Sweden)

    Alessandro Garrett Dronk

    2012-12-01

    Full Text Available For commercial production of orchids, it is essential to use a good substrate, and the selection of this material is very important to evaluate aspects of the economic, physical, chemical, biological, and ecological points of view. The aim of this study was to evaluate the development of clones of BLC Nan Chang Silk ‘Olimpic Torch’ on different substrates. The substrates were: T1: tree fern fiber “xaxim” (control, T2: coconut fiber, T3: composted pine bark, T4: plant coal, T5: composted pine bark + coconut fiber (1:1 v/v T6: coconut fiber + plant coal (1:1 v/v, T7: plant coal + composted pine bark (1:1 v/v, T8: plant coal + composted pine bark + coconut fiber ( 1:1:1 v/v/v. The seedlings were grown in pots of polypropylene, kept in a nursery with 80% of brightness. We evaluated 24 months after the start of the experiment: number of pseudobulbs, the lenght of pseudobulbs, height of the plant area, height of the aerial part / lenght of the pseudobulbs and pH and electrical conductivity of the substrate. Based on the parameters of vegetative development it was concluded that all the evaluated substrates can be efficiently used for the cultivation of BLC Nan Chang Silk ‘Olimpic Torch’. A produção de orquídeas é uma atividade em crescente expansão nos mercados nacional e internacional, tornando-se evidente a necessidade de informações que permitam a otimização do seu cultivo. Para a produção comercial de orquídeas, é imprescindível a utilização de um substrato que permita maior crescimento das mudas e, na seleção deste material, é muito importante avaliar aspectos do ponto de vista econômico, físico, químico, biológico e ecológico. O objetivo deste trabalho foi avaliar o desenvolvimento de clones de BLC Nan Chang Silk ‘Olimpic Torch’, obtida do cruzamento entre BLC. Bryce Canyon x BLC. Pamela Hetherington, em diferentes substratos. Os substratos avaliados foram: T1: fibra de xaxim (controle; T2: fibra de coco

  11. Estimativa do filocrono em milho para híbridos com diferentes ciclos de desenvolvimento vegetativo Estimating the phyllocron in maize hybrids with different cycles of vegetative development

    OpenAIRE

    Juliano Dalcin Martins; Reimar Carlesso; Mirta Terezinha Petry; Alberto Eduardo Knies; Zanandra Boff de Oliveira; Tiago Broetto

    2012-01-01

    O filocrono é definido como o tempo térmico necessário para o aparecimento de folhas sucessivas na haste principal de uma planta. Através do filocrono, pode-se calcular a duração do período vegetativo e, portanto, a época de florescimento em função da temperatura do ar. O presente trabalho teve por objetivo determinar o filocrono de diferentes híbridos de milho. Foram conduzidos três experimentos a campo, nos anos agrícolas de 2007/08, 2008/09 e 2009/2010. O delineamento experimental foi o de...

  12. ‘Who Said It Was Simple!’ Third-Wave Feminist Coalition and Audre Lorde's Intersectionalist Hybrid Poetics of Difference

    OpenAIRE

    Yomna Saber

    2015-01-01

    Third-Wave Feminism digs its roots in intersectionality and coalition, which were not fully realised in Second-Wave Feminism. However, the movement is usually under attack for lacking a clear agenda. Recent scholarship strongly suggests that third wavers get back to third-world writers, like Audre Lorde, to realise an anti-racist and inclusive feminism.  Lorde occupies a distinctive position in feminist literature; a poet who resides in too many margins being black, female and lesbian. This e...

  13. Study of electric and magnetic field fluctuations from lower hybrid drift instability waves in the terrestrial magnetotail with the fully kinetic, semi-implicit, adaptive multi level multi domain method

    Science.gov (United States)

    Innocenti, M. E.; Norgren, C.; Newman, D.; Goldman, M.; Markidis, S.; Lapenta, G.

    2016-05-01

    The newly developed fully kinetic, semi-implicit, adaptive multi-level multi-domain (MLMD) method is used to simulate, at realistic mass ratio, the development of the lower hybrid drift instability (LHDI) in the terrestrial magnetotail over a large wavenumber range and at a low computational cost. The power spectra of the perpendicular electric field and of the fluctuations of the parallel magnetic field are studied at wavenumbers and times that allow to appreciate the onset of the electrostatic and electromagnetic LHDI branches and of the kink instability. The coupling between electric and magnetic field fluctuations observed by Norgren et al. ["Lower hybrid drift waves: Space observations," Phys. Rev. Lett. 109, 055001 (2012)] for high wavenumber LHDI waves in the terrestrial magnetotail is verified. In the MLMD simulations presented, a domain ("coarse grid") is simulated with low resolution. A small fraction of the entire domain is then simulated with higher resolution also ("refined grid") to capture smaller scale, higher frequency processes. Initially, the MLMD method is validated for LHDI simulations. MLMD simulations with different levels of grid refinement are validated against the standard semi-implicit particle in cell simulations of domains corresponding to both the coarse and the refined grid. Precious information regarding the applicability of the MLMD method to turbulence simulations is derived. The power spectra of MLMD simulations done with different levels of refinements are then compared. They consistently show a break in the magnetic field spectra at k⊥di˜30 , with di the ion skin depth and k⊥ the perpendicular wavenumber. The break is observed at early simulated times, Ωcit <6 , with Ωci the ion cyclotron frequency. It is due to the initial decoupling of electric and magnetic field fluctuations at intermediate and low wavenumbers, before the development of the electromagnetic LHDI branch. Evidence of coupling between electric and magnetic

  14. Tratamento de esgoto sanitário em reator híbrido em bateladas sequenciais: eficiência e estabilidade na remoção de matéria orgânica e nutrientes (N, P Sewage treatment in a sequencing batch hybrid reactor: efficiency and stability in organic matter and nutrient (N, P removal

    Directory of Open Access Journals (Sweden)

    Luiz Gonzaga Lamego Neto

    2011-12-01

    Full Text Available Este trabalho apresenta os resultados de estudo sobre o comportamento de um reator híbrido, operado em bateladas sequenciais, na remoção conjunta de matéria carbonácea, nitrogênio e fósforo de esgoto sanitário. Operado em ciclos de 8 horas de duração, o reator possuía em seu interior um suporte fixo com rede de nylon. Foram testadas cargas compreendidas entre 0,39 e 1,35 kgDQO.m-3.dia-1, 42 e 60 gN-NH4-.m-3.dia e 51 e 70 gP-PO4-.m-3.dia. O reator funcionou como um sistema estável e apresentou boas condições de depuração. A remoção da matéria carbonácea mostrou-se elevada, com eficiências médias de 92% de DBO5 e 80% de DQO. A remoção de nutrientes variou entre 59 e 71% para nitrogênio total e entre 45 e 67% para fósforo total. Tanto no lodo em suspensão, quanto no biofilme, foi observada a ocorrência de bactérias oxidadoras de amônio e micro-organismos responsáveis pela desnitrificação e remoção biológica de fósforo.This paper presents the results about the behavior of a sequencing batch hybrid reactor on combined removal of carbonaceous matter, nitrogen and phosphorus from sewage. Operated in 8-hour cycles, the reactor had a nylon net fixed inside. Loads between 0.39 and 1.35 kg COD.m-3.day-1, 42 and 60 gN-NH4-m-3.day-1 and 51 and 70 gP-PO4-m-3.day-1 were tested. The reactor operated as a stable system and showed good depuration conditions. The carbonaceous matter removal was high, with 92 and 80% efficiencies average to BOD5 and COD, respectively. The nutrients removal varied between 59 and 71% for total nitrogen and between 45 and 67% for total phosphorus. In both, sludge in suspension and the biofilm, occurrence of ammonium-oxidizing bacteria and microorganisms responsible for denitrification and biological phosphorus removal was observed.

  15. Analysis and experimental validation of the middle-frequency vibro-acoustic coupling property for aircraft structural model based on the wave coupling hybrid FE-SEA method

    Science.gov (United States)

    Yan, Yunju; Li, Pengbo; Lin, Huagang

    2016-06-01

    The finite element (FE) method is suitable for low frequency analysis and the statistical energy analysis (SEA) for high frequency analysis, but the vibro-acoustic coupling analysis at middle frequency, especially with a certain range of uncertainty system, requires some new methods. A hybrid FE-SEA method is proposed in this study and the Monte Carlo method is used to check the hybrid FE-SEA method through the energy response analysis of a beam-plate built-up structure with some uncertainty, and the results show that two kinds of calculation results match well consistently. Taking the advantage of the hybrid FE-SEA method, the structural vibration and the cabin noise field responses under the vibro-acoustic coupling for an aircraft model are numerically analyzed, and, also, the corresponding experiment is carried out to verify the simulated results. Results show that the structural vibration responses at low frequency accord well with the experiment, but the error at high frequency is greater. The error of sound pressure response level in cabin throughout the spectrum is less than 3 dB. The research proves the reliability of the method proposed in this paper. This indicates that the proposed method can overcome the strict limitations of the traditional method for a large complex structure with uncertainty factors, and it can also avoid the disadvantages of solving complex vibro-acoustic system using the finite element method or statistical energy analysis in the middle frequency.

  16. Hybrid Baryons

    CERN Document Server

    Page, P R

    2003-01-01

    We review the status of hybrid baryons. The only known way to study hybrids rigorously is via excited adiabatic potentials. Hybrids can be modelled by both the bag and flux-tube models. The low-lying hybrid baryon is N 1/2^+ with a mass of 1.5-1.8 GeV. Hybrid baryons can be produced in the glue-rich processes of diffractive gamma N and pi N production, Psi decays and p pbar annihilation.

  17. Fusion of protoplasts with irradiated microprotoplasts as a tool for radiation hybrid panel in citrus Fusão de protoplastos com microprotoplastos irradiados como ferramenta para painel híbrido de radiação em citros

    Directory of Open Access Journals (Sweden)

    Claudine Maria de Bona

    2009-12-01

    Full Text Available The objective of this work was to combine asymmetric somatic hybridization (donor-recipient fusion or gamma fusion to microprotoplast-mediated chromosome transfer, as a tool to be used for chromosome mapping in Citrus. Swinglea glutinosa microprotoplasts were irradiated either with 50, 70, 100 or 200 gamma rays and fused to cv. Ruby Red grapefruit or Murcott tangor protoplasts. Cell colonies were successfully formed and AFLP analyses confirmed presence of S. glutinosa in both 'Murcott' tangor and 'Ruby Red' grapefruit genomes.O objetivo deste trabalho foi combinar hibridação somática assimétrica (fusão doador-recipiente ou fusão gama e transferência cromossômica mediada por microprotoplastos como uma ferramenta para o mapeamento cromossômico em Citrus. Microprotoplastos de Swinglea glutinosa foram irradiados com doses de 50, 70, 100 ou 200 raios gama e fusionados com protoplastos de pomelo cv. Ruby Red ou de tangor Murcott. Houve sucesso na formação de colônias de células, e a análise AFLP confirmou a presença de S. glutinosa nos genomas do tangor 'Murcott' e do pomelo 'Ruby Red'.

  18. Sowing date for forage maize hybrids harvested at different growth stages = Época de semeadura de híbridos de milho forrageiro colhidos em diferentes estádios de maturação

    Directory of Open Access Journals (Sweden)

    Marcelo Cruz Mendes

    2015-06-01

    Full Text Available The sowing dates and harvesting times of forage maize are important factors in high-yield forage production. The objective of this study was to evaluate the participation of plant components for different sowing dates and harvest stages, in commercial maize hybrids recommended for the production of forage. The experimental design was of randomised blocks, three replications, in a 4 x 2 factorial scheme, being four maize hybrids (P30B39H, DKB245, 2B688H and DKB330Y and two sowing dates (October and November. The experiment was carried out in Guarapuava, in the state of Paraná, Brazil (PR. Evaluations were done at stages R4 and R5, when the percentage of dry matter was evaluated by means of fractionation for the leaves (PPFOL, stem (PPCOL, grain (PPGR, and bracts and cob (PPSAB. The hybrid DKB245 displayed less participation of the leaves, stem, bracts and cob, and a higher participation of grain at the farinaceous and hard farinaceous grain reproductive stages, irrespective of sowing time. With the advancement of the farinaceous grain reproductive stage to hard farinaceous grain, there was an increase in the percentage of grain in the hybrids under evaluation and a reduction in the participation of the leaves, stem, bracts and cob for the two sowing dates (October and November. At the hard farinaceous grain stage, the genotypes under evaluation were less influenced by the effect of sowing time, there being a greater participation of the grain for all genotypes; with the hard farinaceous grain stage being indicated for harvesting the forage. = Época de semeadura e ponto de corte de plantas de milho forrageiro são fatores importantes na produção de forragem de alto rendimento. O objetivo deste trabalho foi avaliar a participação dos componentes da planta em diferentes épocas de semeadura e estádios de colheita, em híbridos comerciais de milho recomendados para produção de forragem. O delineamento foi em blocos casualizados, com tr

  19. Características agronômicas e estruturais de híbridos de sorgo em função de diferentes densidades de plantio Agronomic characteristics of sorghum hybrids cultivated with different plant populations

    Directory of Open Access Journals (Sweden)

    Poliana Mendes Avelino

    2011-06-01

    Full Text Available Foram avaliadas as características agronômicas dos híbridos de sorgo, AG-2005 (duplo propósito e VOLUMAX (forrageiro para produção de silagem, cultivados nos espaçamentos de 1,00; 0,75; e 0,50 m entre linhas em Neossolo Quartzarênico Órtico, resultando nas densidades de 140.000; 186.666 e 280.000 plantas por hectares, respectivamente. Para tais avaliações foi utilizado o delineamento experimental de blocos ao acaso num arranjo fatorial (2 x 3. Foram determinadas as produções de matéria seca total (PMST, de lâmina foliar (PMLF, de caule (PMSC e de panícula (PMSP, bem como suas proporções na planta inteira. Ocorreu interação significativa entre híbrido de sorgo e espaçamento para as características PMST, PMSLF e PMSP. O híbrido VOLUMAX apresentou produções semelhantes nos três espaçamentos testados. O AG-2005 apresentou maior PMST (9.474,59 vs 6.842,91 kg ha-1 e PMSP (6.355,77 vs 3.032,40 kg ha-1 em relação ao VOLUMAX no espaçamento 0,50 m. O AG-2005 foi superior ao VOLUMAX no percentual de panícula nos espaçamentos 1,00 m (57,06 vs 40,22% e 0,50 m (66,99 vs 43,55% e o VOLUMAX foi superior no percentual de colmo nos espaçamentos 1,00 e 0,50 m. Recomenda-se o uso do híbrido AG-2005 cultivado sob espaçamento de 0,50 m para produção de silagem, em virtude da maior produção de MS por área, maior percentual de panícula e menor percentual de colmo na composição da planta em comparação ao híbrido VOLUMAX.The objective of the experiment was to evaluate the agronomic characteristics of two sorghum hybrids for silage production, AG-2005 (double purpose and VOLUMAX (forage cultivated with different row spacing 1; 0.75 and 0.50 m, on Orthic Quartzarenic Neosol, resulting in 140,000; 186,666 e 280,000 plants per ha, respectively. A randomized block design with four replicates was used and the treatments consisted on a factorial arrangement 2 x 3. Were determined the total dry matter production (PMST, of leaves

  20. Numerical simulation of bistatic scattering from a target at low altitude above rough sea surface under an EM wave incidence at low grazing angle by using the finite element method

    Institute of Scientific and Technical Information of China (English)

    LIU Peng; JIN Yaqiu

    2004-01-01

    To study bistatic scattering from a target at low altitude above two- dimensional (2D) randomly rough sea surface under an electromagnetic (EM) wave incidence at low grazing angle (LGA), a numerical approach of the finite element method (FEM) is developed. The conformal perfectly matched layer (PML), as the truncation boundary of the FEM, is employed to reduce the reflection error of planar PML in conventional FEM. Numerical code of our FEM is examined by available solution of the forward backward iterative (FBM) method. Bistatic and back-scattering from composite model of a target above random rough sea surface generated by Monte Carlo realization, and functional dependence upon the sea surface wind speed, target altitude, incident and scattering angles, etc. are numerically simulated and discussed. This paper presents a numerical description of the observation principle and physical insight associated with the coupling interactions of a complex volumetric target and random rough sea surface.

  1. Caracterização citogenética, viabilidade de pólen e hibridação artificial em gérbera Chromosome number, pollen viability and gerbera hybridization

    Directory of Open Access Journals (Sweden)

    Raquel DL Cardoso

    2009-03-01

    Full Text Available Este trabalho foi conduzido com o objetivo de confirmar o número de cromossomos em cultivares de Gerbera hybrida Hort., determinar o número de cromossomos em acessos não comerciais de Gerbera sp., avaliar a viabilidade de pólen e a possibilidade de cruzamentos entre cultivares e acessos não comerciais. Foram coletados ápices de raízes e pólen de seis cultivares e de sete acessos não comerciais. O material coletado foi corado com carmim acético a 45%. A contagem dos cromossomos foi realizada em células metafásicas intactas e a estimativa de viabilidade de pólen realizada por meio da contagem do número de grãos de pólen viáveis e não viáveis. A possibilidade de cruzamento entre as cultivares e entre as cultivares e acessos não comerciais foi avaliada por meio da hibridação entre os genitores femininos, cv. Terra Fame e acesso A8, e masculinos, cvs. Cariba e Azteca. Todos os acessos contiveram cinqüenta cromossomos, indicando que a variação morfológica nos capítulos (simples, semidobrado e dobrado não é devida a mutações cromossômicas numéricas ou a poliploidia. A viabilidade do pólen variou de 87,67% a 99,27%. A formação de sementes foi de 4,46% nos cruzamentos entre cultivares, e de 50% entre o A8 e as cultivares. A compatibilidade genômica entre os acessos, a alta viabilidade do pólen e o sucesso na obtenção de sementes entre acessos comercias e não comerciais, revela a possibilidade de produção de híbridos com novas combinações alélicas e transferência de caracteres desejáveis dos acessos não comerciais para os comerciaisThis work was conducted to confirm the chromosomes number of Gerbera hybrida Hort. cultivars, to determine the chromosomes number in the non commercial accessions of Gerbera sp., and to estimate the pollen viability and the possibility of crossings among different accessions. Root-tip and pollen were collected from six cultivars and seven non commercial accessions. The collected

  2. Genitores potenciais para hibridações identificados por divergência genética em feijão carioca Bean parents for hybridization identified by genetic divergence in "carioca" bean

    Directory of Open Access Journals (Sweden)

    Nerinéia Dalfollo Ribeiro

    2003-06-01

    Full Text Available Noventa genótipos de feijão carioca (Phaseolus vulgaris L. foram avaliados, em dois anos agrícolas, em Santa Maria, RS, a fim de definir quais características agromorfológicas constituem-se como melhores descritores, realizar agrupamento em função de dissimilaridade genética e de definir quais combinações híbridas mais promissoras serão obtidas para o desenvolvimento de populações segregantes. Dos 20 caracteres agromorfológicos avaliados, apenas nove (ferrugem nos legumes, acamamento, nota geral, cor do tegumento, rendimento de grãos, massa de 100 sementes, altura de inserção do primeiro legume, altura de inserção do último legume e número de sementes por legume apresentaram maior contribuição para a divergência genética. Os genótipos de feijão carioca foram agrupados pelo método hierárquico de ligação completa. Populações segregantes, com variabilidade genética superior, podem ser obtidas com hibridações entre o genótipo ESAL 550 com genótipos do grupo 2 (LH-6, 17-4-32, R-78, H-4-5 e R-102 e/ou com genótipos do grupo 3 (FT 97-188, Cati-Taquari, CII-328, Carioca Precoce, FT 97-41, LH-11, FT 91-4067, Iapar 31, CI 102, Carioca MG, CII-54 e R-102.Carioca bean genotypes (Phaseolus vulgaris L. were evaluated in two growing seasons in Santa Maria, RS, Brazil. The objectives of this work were to evaluate which morpho-agronomic characteristics were the best descriptors, to group the genotypes in relation to genetic diversity and to determine which hybrid combinations are promissing to obtain higher segregation populations in carioca bean. From the 20 morpho-agronomic characteristics evaluated, only seven (pod rust, lodging, general note, colour of seed tegument, grain yield, 100 seed weight, height of first and final pod insertion and number of seeds per pod showed higher contribution to genetic diversity. The evaluated carioca bean genotypes were clustered by the complete linkage method. The following hybrid

  3. Desempenho de híbridos de linhagens parcialmente endogâmicas de milho em regiões dos estados de Roraima e Minas Gerais Performance of hybrids of partially endogamic lines s2 of maize in regions of the states of Roraima and Minas Gerais

    Directory of Open Access Journals (Sweden)

    Agnaldo Donizete Ferreira de Carvalho

    2003-10-01

    17% dos híbridos de LPE S2 tiveram desempenho superior ao híbrido simples C-333B C (10,76 t/ha e 46% apresentaram desempenho superior à testemunha C-435 (9,56 t/ha, um híbrido duplo amplamente utilizado nos dois estados. Para ALTP e ALTE, os resultados foram semelhantes a PESP, salientado que o contraste H vs T foi não-significativo, inferindo-se que os híbridos S2 e as testemunhas apresentaram, em média, as mesmas ALTP e ALTE. Com esse fato, evidencia-se que os híbridos LPE S2 são semelhantes aos híbridos comerciais e mostra o potencial da utilização desse tipo de híbridos no Brasil, que pode substituir com vantagens alguns híbridos comerciais disponíveis no mercado.Among the types of maize hybrids those from S2 families have the advantage of higher synthesis speed. S2 families can be obtained from any kind of population, but a good option are those derived from commercial single cross hybrids that associate productivity and many segregant loci. So, the objective of the research way to evaluate hybrids derived from S2 families descendant of three single cross hybrids. The selection of hybrids was atrained from 30 S2 families derived of three segregant populations descendent of the commercial hybrids AG- 9012, C-333B and Z-8392. Three crossings were carried out using a circular partial diallel scheme, when each family from one population was crossed with three other families from other population. For the crossings the families had been sown, in line of 10 m long. When the first ear emerged, it was protected and during the pollination time a mixture of pollen of each family was used to pollinate at least ten plants of a family of an other population. The hybrids were evaluated in Boa Vista, Roraima state and Minas Gerais state, Brazil, using the simple lattice design 12x12, including 135 hybrids and nine checks. The checks were the F1 generation of the single cross hybrids AG 9012, C333 and Z 8392, a double cross hybrid (435 and five other intervariety

  4. Hybrid instrument applied to human reliability study in event of loss of external electric power in a nuclear power plant; Instrumento hibrido aplicado ao estudo da confiabilidade humana em evento de perda de energia eletrica externa em usina nuclear

    Energy Technology Data Exchange (ETDEWEB)

    Martins, Eduardo Ferraz

    2015-04-01

    The study projects in highly complex installations involves robust modeling, supported by conceptual and mathematical tools, to carry out systematic research and structured the different risk scenarios that can lead to unwanted events from occurring equipment failures or human errors. In the context of classical modeling, the Probabilistic Safety Analysis (PSA) seeks to provide qualitative and quantitative information about the project particularity and their operational facilities, including the identification of factors or scenarios that contribute to the risk and consequent comparison options for increasing safety. In this context, the aim of the thesis is to develop a hybrid instrument (CPP-HI) innovative, from the integrated modeling techniques of Failure Mode and Effect Analysis (FMEA), concepts of Human Reliability Analysis and Probabilistic Composition of Preferences (PCP). In support of modeling and validation of the CPP-HI, a simulation was performed on a triggering event 'Loss of External Electric Power' - PEEE, in a Nuclear Power plant. The results were simulated in a virtual environment (sensitivity analysis) and are robust to the study of Human Reliability Analysis (HRA) in the context of the PSA. (author)

  5. Square wave series voltage compensator with high frequency DC-DC converter; Compensador serie de tensao em onda quadrada com conversor CC-CC de alta frequencia

    Energy Technology Data Exchange (ETDEWEB)

    Moreira, Angelo Roberto Rodrigues Resende; Caetano, William Douglas; Pires, Igor Amariz; Silva, Arlete Vieira da [Centro Universitario de Belo Horizonte (UnBH), MG (Brazil)], e-mails: angelogalo2005@hotmail.com, wdouglasbh@gmail.com, igor_amariz@yahoo.com.br, arlete.silva@prof.unibh.br

    2011-07-01

    The square wave series voltage compensator is an equipment used to mitigate voltage sags. In the case of occurrence of a voltage disturbance, the compensator acts generating a square wave voltage to supply the missing voltage. The energy inserted for the compensation is taken from the electrical grid, by a linear source. The purpose of this paper is to present a switching shunt converter instead of a linear one, with the same output parameters in order to increase the power density. This efficiency is demonstrated by simulations. (author)

  6. Prediction of genetic gain from selection indices for disease resistance in papaya hybrids Predição de ganhos genéticos para resistência a doenças por índices de seleção em híbridos de mamoeiro

    Directory of Open Access Journals (Sweden)

    Marcelo Vivas

    2012-12-01

    Full Text Available In order to select superior hybrids for the concentration of favorable alleles for resistance to papaya black spot, powdery mildew and phoma spot, 67 hybrids were evaluated in two seasons, in 2007, in a randomized block design with two replications. Genetic gains were estimated from the selection indices of Smith & Hazel, Pesek & Baker, Williams, Mulamba & Mock, with selection intensity of 22.39%, corresponding to 15 hybrids. The index of Mulamba & Mock showed gains more suitable for the five traits assessed when it was used the criterion of economic weight tentatively assigned. Together, severity of black spot on leaves and on fruits, characteristics considered most relevant to the selection of resistant materials, expressed percentage gain of -44.15%. In addition, there were gains for other characteristics, with negative predicted selective percentage gain. The results showed that the index of Mulamba & Mock is the most efficient procedure for simultaneous selection of papaya hybrid resistant to black spot, powdery mildew and phoma spot.Com a finalidade de selecionar híbridos superiores para concentração de alelos favoráveis à resistência de mamoeiro à pinta-preta, oídio e mancha de phoma, foram avaliados, em duas épocas, em 2007, 67 híbridos simples, em delineamento de blocos casualizados com duas repetições. Os ganhos genéticos foram estimados a partir dos índices de seleção de Smith & Hazel, Pesek & Baker, Williams e Mulamba & Mock, com intensidade de seleção de 22,39%, correspondendo a 15 híbridos. O índice de Mulamba & Mock evidenciou ganhos mais adequados para as cinco características avaliadas, quando utilizado o critério de peso econômico atribuído por tentativas. Em conjunto, as severidades da pinta-preta em folhas e em frutos, características consideradas de maior interesse para a seleção de materiais resistentes, expressaram ganho percentual de -44,15%. Além disso, registraram-se ganhos para as demais

  7. Eu(III) local coordination in white light emitters organic-inorganic hybrids; Coordenacao local do Eu(III) em hibridos organicos-inorganicos emissores de luz branca

    Energy Technology Data Exchange (ETDEWEB)

    Carlos, Luis D.; Ferreira, Rute A. Sa [Universidade de Aveiro (Portugal). Dept. de Fisica]. E-mail: lcarlos@ideiafix.fis.ua.pt; Bermudez, Veronica Zea de [Universidade de Tras-os-Montes e Alto Douro, Quinta de Prados (Portugal). Dept. de Quimica; Bueno, Luciano A.; Molina, Celso; Messaddeq, Younes; Ribeiro, Sidney J.L. [UNESP, Araraquara, SP (Brazil). Inst. de Quimica]. E-mail: sidney@iq.unesp.br

    2001-08-01

    Eu{sup 3+} luminescence and EXAFS (Extended X-Ray Absorption Fine Structure) results are presented for organic-inorganic hybrid gel hosts composed of a siliceous network to which small chains of oxy ethylene units are covalently grafted by means of urea bridges. Coordination numbers for Eu {sup 3+} ions range from 12.8 to 9.7 with increasing Eu {sup 3+} concentration while the Eu {sup 3=}-first neighbours mean distance is found to be constant at 2.48-2.49 angstrom in the same concentration range. Emission spectra display a broad band in the green/blue spectral region superposed to narrow lines appearing in the yellow/red region in such a way that for the eyes emission appears white. The broad band is assigned to intrinsic N H groups emission and also to electron-hole recombination in the nanosized siliceous domains. The narrow lines are assigned to intra-4f{sup 6}, {sup 5} D{sub 0}{yields}{sup 7} F{sub 0-4} Eu {sup 3+} transitions and from the energy position of the {sup 7} F{sub 0-4} levels a mean distance could be calculated for the Eu {sup 3+}-first neighbours. The calculated results are in good agreement with the experimental ones obtained from EXAFS analysis. (author)

  8. Hybrid environmental robot: a tool for monitoring gas on flooded area; Robo ambiental hibrido: utilizacao como ferramenta para monitoramento de gases em areas alagadas

    Energy Technology Data Exchange (ETDEWEB)

    Goes, Emerson de; Cerqueira, Romulo Curty; Reis, Ney Robinson S. [PETROBRAS, Rio de Janeiro, RJ (Brazil)

    2008-07-01

    The impoundment of rivers for power generation leads to flooding of vast areas of land vegetation. Most submerged plants, die and enter into decomposition, releasing CO2 (carbon dioxide), CH4 (methane gas) into the air for many years. Scientists from around the world seek to clarify the processes to which these gases are submitted and their contributions to the process of global warming. Estimates suggest that the re-use of methane that passes through the turbines of these power plants could increase their energy potential by 75% and reduce their emissions of these gases by 65%, reducing their impact on global warming and resulting in carbon credits. To check the feasibility of using new processes and technologies to generate energy that recycles this biogas, operations for monitoring these biogases become routine tasks. The frequency is such that the exposure of humans to the risks of gas combustion, inherent to scenarios where these operations take place, becomes unacceptable. This motivates the use of robots in this activity. This paper presents the multi-mission platform Hybrid Environmental Robot, named 'Chico Mendes', as a tool for tracking gas emission and specially designed for flooded forest areas.

  9. On the modeling of planetary plasma environments by a fully kinetic electromagnetic global model HYB-em

    Directory of Open Access Journals (Sweden)

    V. Pohjola

    2010-03-01

    Full Text Available We have developed a fully kinetic electromagnetic model to study instabilities and waves in planetary plasma environments. In the particle-in-a-cell (PIC model both ions and electrons are modeled as particles. An important feature of the developed global kinetic model, called HYB-em, compared to other electromagnetic codes is that it is built up on an earlier quasi-neutral hybrid simulation platform called HYB and that it can be used in conjunction with earlier hybrid models. The HYB models have been used during the past ten years to study globally the flowing plasma interaction with various Solar System objects: Mercury, Venus, the Moon, Mars, Saturnian moon Titan and asteroids. The new stand-alone fully kinetic model enables us to (1 study the stability of various planetary plasma regions in three-dimensional space, (2 analyze the propagation of waves in a plasma environment derived from the other global HYB models. All particle processes in a multi-ion plasma which are implemented on the HYB platform (e.g. ion-neutral-collisions, chemical processes, particle loss and production processes are also automatically included in HYB-em model.

    In this brief report we study the developed approach by analyzing the propagation of high frequency electromagnetic waves in non-magnetized plasma in two cases: We study (1 expansion of a spherical wave generated from a point source and (2 propagation of a plane wave in plasma. The analysis shows that the HYB-em model is capable of describing these space plasma situations successfully. The analysis also suggests the potential of the developed model to study both high density-high magnetic field plasma environments, such as Mercury, and low density-low magnetic field plasma environments, such as Venus and Mars.

  10. Localized lower hybrid acceleration of ionospheric plasma

    Science.gov (United States)

    Kintner, P. M.; Vago, J.; Chesney, S.; Arnoldy, R. L.; Lynch, K. A.; Pollock, C. J.; Moore, T. E.

    1992-01-01

    Observations of the transverse acceleration of ions in localized regions of intense lower hybrid waves at altitudes near 1000 km in the auroral ionosphere are reported. The acceleration regions are thin filaments with dimensions across geomagnetic field lines of about 50-100 m corresponding to 5-10 thermal ion gyroradii or one hot ion gyroradius. Within the acceleration region lower hybrid waves reach peak-to-peak amplitudes of 100-300 mV/m and ions are accelerated transversely with characteristic energies of the order of 10 eV. These observations are consistent with theories of lower hybrid wave collapse.

  11. Uso da técnica de Southern Blot/Hibridização associada à reação em cadeia da polimerase para aumentar a sensibilidade no diagnóstico das infecções por hemoplasmas em gatos domésticos: Use of Southern Blot/Hybridization technique associated to polymerase chain reaction to improve the sensitivity in the diagnosis of hemoplasma infections in domestic cats

    Directory of Open Access Journals (Sweden)

    Daniel B. Macieira

    2009-12-01

    Full Text Available O objetivo deste trabalho foi verificar se a técnica de Southern Blot/Hibridização (SB em associação à reação de polimerização em cadeia (PCR aumenta a sensibilidade na detecção de DNA de hemoplasmas em gatos domésticos (Felis catus. O sangue total foi coletado em tubos contendo o anticoagulante ácido etilenodiamino tetra-acético, o DNA extraído a partir de 149 animais e a PCR realizada com o uso de sequências iniciadoras espécie-específicas, para amplificar subunidade 16S do RNA ribossomal de Mycoplasma haemofelis e 'Candidatus M. haemominutum' dessas amostras. Para a hibridização, foram utilizadas sondas específicas quimicamente marcadas, e os resultados visualizados por meio da adição de substrato quimiluminescente seguida de autoradiografia. Dezoito (12,1% das 149 amostras testadas apresentaram resultado PCR-positivo para o DNA de hemoplasmas. A técnica de SB mostrou que 24/149 (16,1% amostras apresentaram resultado positivo para hemoplasmas, confirmando os 18 resultados PCR-positivos, além de revelar seis outros adicionais (p The aim of this study was to determine whether Southern Blot/Hybridization (SB associated to Polymerase Chain Reaction (PCR improves the sensitivity in the detection of hemoplasma DNA in domestic cats (Felis catus. Whole blood was collected in tubes containing the anticoagulant ethylenediamine tetra-acetic acid and DNA extracted from 149 animals. PCR was performed using species specific primers to amplify the 16S ribosomal RNA subunit of Mycoplasma haemofelis and 'Candidatus M. haemominutum' from these samples. Hybridization was performed using a 16S rDNA probes chemically labeled and the results were visualized using a chemiluminescent substrate addition followed by autoradiography. Eighteen (12.1% of the 149 tested samples had a positive PCR result for hemoplasma species DNA. SB/hybridization technique showed that 24/149 (16.1% samples were positive for hemoplasmas, confirming the 18 PCR

  12. Avaliação de citrandarins e outros híbridos de trifoliata como porta-enxertos para citros em São Paulo Performance of citrandarins and others trifoliate hybrids rootstocks in Sao Paulo, Brazil

    Directory of Open Access Journals (Sweden)

    Silvia Blumer

    2005-08-01

    Full Text Available Laranjeiras Valência enxertadas em citrandarins e outros híbridos de trifoliata foram plantadas em 1988, em Itirapina (SP, num Latossolo Vermelho-Amarelo textura arenosa e conduzidas sem irrigação. O citrandarin Sunki x English (1.628, sem diferir estatisticamente de Cleópatra x Rubidoux (1.660, Cleópatra x English (710, Cleópatra x Swingle (715 e do trangpur Cravo x Carrizo (717, induziu a maior produção de frutos nas cinco primeiras colheitas do experimento (1991-1995, sendo que os três primeiros foram os mais produtivos nas três últimas colheitas. Os citranges Troyer e Carrizo foram significativamente inferiores aos citrandarins Sunki x English (1.628, Cleópatra x Rubidoux (1.660 e Cleópatra x English (710 em todos os anos, exceto 1994. Nenhuma das plantas apresentou sintomas de suscetibilidade à tristeza ou ao declínio. Os seedlings dos porta-enxertos diferiram quanto à área lesionada pela inoculação com Phytophthora parasitica. Os citrandarins Cleópatra x Swingle (1.587, Cleópatra x Trifoliata (1.574, Cleópatra x Rubidoux (1.600, Clementina x Trifoliata (1.615 e o limão Cravo x citrange Carrizo (717 foram significativamente mais resistentes que Cleópatra x Christian (712, Sunki x English (1.628, Cleópatra x Swingle (715 e Cleópatra x English (710.Valencia sweet orange trees budded onto citrandarins and others trifoliate hybrids rootstocks from the USDA Horticultural Research Laboratory, Fort Pierce, Florida, were planted in 1988 on a sandy textured Oxisol in São Paulo State, Brazil, and managed without irrigation. Tristeza and blight diseases are endemic in this area. Trees of Sunki x English (1.628, Cleopatra x Rubidoux (1.660, Cleopatra x English (710, Cleopatra x Swingle (715 and Rangpur lime x Carrizo citrange (717, produced the highest cumulative yields in the first five crops (1991-1995. The first three rootstocks induced the highest crops in the last three years. Carrizo and Troyer citranges had the lowest

  13. Cultivo de embriões em retrocruzamentos entre Triticum aestivum Thell. e Agropyron elongatum host. & beauv. Embryo culture of backcrosses between hybrids of Triticum aestivum Thell. and Agropyron elongatum host. & beauv.

    Directory of Open Access Journals (Sweden)

    Dilma Cristina Angra

    1999-02-01

    Full Text Available A resistência a diversas moléstias fúngicas do trigo tem sido transferida de espécies perenes da tribo Triticeae, mas o híbrido produzido pelo cruzamento intergenérico apresenta embrião abortivo. Embora a técnica de resgate e cultivo in vitro destes embriões já seja amplamente utilizada, sua eficiência ainda é muito baixa. Este trabalho objetivou a obtenção de progênies de retrocruzamentos em híbrido F1 (2n=56, proveniente do cruzamento de trigo (Triticum aestivum (2n=42 com Agropyron elongatum (2n=70, utilizando-se a técnica de cultivo in vitro dos embriões imaturos. Partindo-se do material perene na geração F1, utilizou-se o trigo como parental recorrente nos retrocruzamentos. A eficiência da polinização foi de 6% no primeiro retrocruzamento (RC1 e de 12,4% no segundo (RC2. As plantas do RC1 foram viabilizadas pelo resgate e cultivo in vitro dos embriões imaturos utilizando- se o meio batata-regeneração, com adição de vitaminas. De 22 sementes, 18 embriões foram resgatados e cultivados in vitro, originando 12 plântulas. Desses embriões, 50% foram normais, 27,8% apresentaram tamanho reduzido, 16,7% foram deformados e 5,5% apresentaram desenvolvimento retardado. A eficiência do cultivo dos embriões na regeneração de plântulas foi de 66,6%. Tal resultado indica que a técnica de resgate e o meio de cultura utilizados foram eficientes para o cultivo e regeneração dos embriões híbridos, obtendo progênies viáveis de retrocruzamentos a partir de híbridos intergenéricos, nas condições realizadas.Resistance to fungal diseases of wheat has been transferred from perennial species of tribe Triticeae, but the hybrid so formed presents immature embryos. Although rescue and in vitro culture of these embryos has been widely utilized, its efficiency is still very low. This work aimed to obtain backcrossing progenies in hybrid F1 (2n=56, derived from crossing between wheat (Triticum aestivum (2n=42 and Agropyron

  14. Densidade, teor de óleo e produtividade de grãos em híbridos de milho Kernell density, oil content and yield of maize hybrids

    Directory of Open Access Journals (Sweden)

    Aildson Pereira Duarte

    2008-01-01

    Full Text Available Existe grande variabilidade das cultivares de milho quanto à densidade de grãos no mercado brasileiro, mas se conhece pouco sobre seus teores de óleo. Objetivou-se estudar a variabilidade do teor de óleo nos grãos de híbridos de milho e verificar a existência de correlação entre a produtividade, a densidade e o teor de óleo. Desenvolveram-se, na safra 2002/2903, dois experimentos de avaliação de cultivares, em Assis e Adamantina (SP, utilizando o delineamento em blocos ao acaso com 39 híbridos simples e triplos. Foram utilizadas dez espigas por parcela, as quais foram secionadas transversalmente na região mediana para amostragem de grãos, na face exposta. Avaliaram-se a produtividade dos genótipos, a massa de cem grãos, a proporção de grãos boiantes em solução-padrão de nitrato de sódio, o peso volumétrico e o teor de óleo dos grãos pelo método de espectrometria de ressonância magnética nuclear (RMN. Procedeu-se à análise de variância dos dados e a comparação das médias pelo teste de Skott-Knott a 5%. Calcularam-se correlações de Pearson entre o teor de óleo e os demais parâmetros avaliados, utilizando o programa SAS. Os teores de óleo variaram entre 38 a 60 g kg-1. O valor médio de massa volumétrica foi relativamente elevado (796 e 801 g L-1 devido à predominância de cultivares com grãos de aparência dura. As correlações obtidas no experimento evidenciam que híbridos de grãos mais densos tendem a ter maiores teores de óleo (r = 0,34 a 0,40. Três híbridos, no entanto, proporcionaram grãos menos densos e teores de óleo relativamente elevados. As cultivares com maior produtividade tiveram menor teor de óleo, embora o índice de correlação tenha sido baixo (r = -0,24. Concluiu-se que existe variabilidade genética do teor de óleo nos grãos suficiente para discriminar grupo de materiais com teores mais elevados. O teor de óleo correlacionou-se positivamente com a densidade de grãos, por

  15. A Low Cost Air Hybrid Concept Un concept hybride à air et à bas prix

    Directory of Open Access Journals (Sweden)

    Lee C. Y.

    2010-02-01

    Full Text Available The air hybrid engine absorbs the vehicle kinetic energy during braking, stores it in an air tank in the form of compressed air, and reuses it to propel a vehicle during cruising and acceleration. Capturing, storing and reusing this braking energy to give additional power can therefore improve fuel economy, particularly in cities and urban areas where the traffic conditions involve many stops and starts. In order to reuse the residual kinetic energy, the vehicle operation consists of 3 basic modes, i.e. Compression Mode (CM, Expander Mode (EM and normal firing mode. Unlike previous works, a low cost air hybrid engine has been proposed and studied. The hybrid engine operation can be realized by means of production technologies, such as VVT and valve deactivation. In this work, systematic investigation has been carried out on the performance of the hybrid engine concept through detailed gas dynamic modelling using Ricardo WAVE software. Valve timing optimization has been done for the more efficient operation of air hybrid operation and obtaining higher braking and motoring mean effective pressure for CM and EM respectively. Le moteur hybride à air absorbe l’énergie cinétique du véhicule en cas de freinage, la stocke sous forme d’air comprimé, puis la réutilise pour faire avancer le véhicule en circulation ou en accélération. Capter, stocker et réutiliser cette énergie et créer ainsi une puissance plus importante peut donc permettre de plus grandes économies de carburant, surtout en ville et zone urbaine, lorsque les conditions de circulation imposent de nombreux arrêts et démarrages. Pour pouvoir réutiliser l’énergie cinétique, on distingue trois modes de base d’utilisation du véhicule : les modes compression (MC, expansion (ME et standard. Un moteur hybride à air et à bas prix a été proposé et étudié. Un tel moteur peut être opéré par le biais de technologies de production, comme le VVT et la d

  16. Tunable electromagnetically induced transparency in hybrid graphene/all-dielectric metamaterial

    Science.gov (United States)

    Zhu, Lei; Dong, Liang; Guo, Jing; Meng, Fan-Yi; Wu, Qun

    2017-03-01

    We proposed a hybrid graphene/dielectric structure to achieve tunable electromagnetically induced transparency (EIT) effect. Unit cell of hybrid structure consists of a graphene strip as bright element and a dielectric split ring resonator (DSRR) as quasi-dark element. The destructive inference between dipolar plasmon resonance induced by graphene strip and Mie resonance induced by DSRR leads to famous EIT effect. By altering physical sizes of two resonant elements and their couplings, EIT resonance can be effectively controlled. In particular, EIT window and effective group index can be dynamically dominated by varying graphene strip's Fermi level. This active manipulation is also confirmed using "two-particle" model. More interestingly, EIT resonance can be also effectively modulated through controlling incident angles for electromagnetic (EM) waves. These results would have promising applications in areas of tunable slow light devices and new filters.

  17. Características fenológicas, produtivas e qualitativas de híbridos de girassol em diferentes épocas de semeadura para produção de silagem Sowing dates effects on the phenology, yield and qualitative traits of sunflower hybrids for silage making

    Directory of Open Access Journals (Sweden)

    Renius Mello

    2006-06-01

    Full Text Available Objetivou-se verificar o efeito de três épocas de semeadura - outubro (antecipada, novembro (normal e dezembro (tardia - sobre as características fenológicas, produtivas e qualitativas de quatro híbridos de girassol: Rumbosol-91 (forrageiro, M-734 (duplo propósito, C-11 (duplo propósito e BRS-191 (granífero destinados à produção de silagem. O delineamento experimental foi em blocos ao acaso, com arranjo fatorial 4 x 3 (quatro híbridos x três épocas de semeadura e quatro repetições. A semeadura em outubro resultou em ciclo mais longo, altura de planta mais elevada e diâmetro e participação de capítulo menores, como conseqüência da temperatura, da insolação e do fotoperíodo, que foram mais baixos nessa época. Os híbridos Rumbosol-91 e BRS-191 semeados em novembro apresentaram taxas de acamamento mais quebramento maiores, de 49,6 e 65,7%, respectivamente. Os híbridos BRS-191 e M-734 semeados em dezembro apresentaram produtividades de fitomassa maiores, com 39,71 e 43,76 t ha-1 de matéria verde e 11,31 e 11,41 t ha-1 de matéria seca, respectivamente. Nos constituintes da planta, os teores de PB aumentaram e os de FDN, FDA e LDA diminuíram, respectivamente, para colmo, folhas e capítulo. Na planta inteira, os teores de MS oscilaram de 23,2%, para o híbrido Rumbosol-91 semeado em novembro, a 47,9%, para o híbrido C-11 semeado em dezembro, indicando que os híbridos possuem capacidade diferenciada de retenção de umidade em estádio de maturidade fisiológica semelhante da cultura (fase R-9. Os teores de PB variaram de 7,0 a 15,7%, demonstrando a riqueza protéica da cultura. Os teores de LDA da planta inteira oscilaram de 6,5 a 12,4%, sendo que os híbridos M-734 semeado em dezembro e C-11 semeado em outubro apresentaram os teores mais baixos. Visando à produção de silagem de elevada qualidade, o híbrido M-734 semeado em dezembro apresentou melhor relação entre fenologia, produtividade e composição bromatol

  18. Relações de causa e efeito em espigas de milho relacionadas aos tipos de híbridos Path analysis on maize spikes characteristics related of the hybrid type

    Directory of Open Access Journals (Sweden)

    Sidinei José Lopes

    2007-12-01

    Full Text Available O peso de grãos é um dos componentes determinantes do rendimento de grãos de milho, que apresenta relações complexas com várias características morfológicas da espiga. O objetivo deste trabalho foi verificar como o peso dos grãos das espigas de milho está relacionado diretamente ou indiretamente com as características morfológicas das espigas e se esta relação depende do tipo de híbrido: simples, triplo ou duplo. O experimento de milho foi realizado no ano agrícola de 2004/05, na Universidade Federal de Santa Maria, com seis tratamentos, que foram compostos de dois híbridos simples, dois híbridos triplos e dois híbridos duplos. O delineamento utilizado foi o de blocos completos ao acaso, com três repetições, com parcelas de duas filas de cinco metros de comprimento com 0,8 m entre filas e densidade de 55.000 plantas ha-1. As correlações entre as características morfológicas da espiga e o peso de grãos foram desdobradas em efeitos diretos e indiretos. O número de filas de grãos por espiga está correlacionado com o peso de grãos apenas nos híbridos duplos (0,5298, e esta correlação se deve ao efeito indireto positivo do número de grãos por espiga (0,8875 e negativo do peso de 100 grãos (- 0,3795. A seleção de espigas com maior peso de 100 grãos e maior número de grãos por espiga tem efeito direto sobre o aumento do peso de grãos por espiga nos híbridos simples e triplo, enquanto que, no híbrido duplo, apenas o número de grãos por espiga tem efeito. As relações entre as características de espigas são dependentes dos genótipos, o que deve complicar um pouco mais a tarefa dos melhoristas de plantas ao selecionar genótipos para maior peso de grão por espiga.The weight of grains is one of the decisive components of the income of corn yield, and presents complex relationships with several morphologic characteristics of the maize spikes. The objective of this research was to verify if the grain weight

  19. Study on the electromagnetic waves propagation characteristics in partially ionized plasma slabs

    Directory of Open Access Journals (Sweden)

    Zhi-Bin Wang

    2016-05-01

    Full Text Available Propagation characteristics of electromagnetic (EM waves in partially ionized plasma slabs are studied in this paper. Such features are significant to applications in plasma antennas, blackout of re-entry flying vehicles, wave energy injection to plasmas, and etc. We in this paper developed a theoretical model of EM wave propagation perpendicular to a plasma slab with a one-dimensional density inhomogeneity along propagation direction to investigate essential characteristics of EM wave propagation in nonuniform plasmas. Particularly, the EM wave propagation in sub-wavelength plasma slabs, where the geometric optics approximation fails, is studied and in comparison with thicker slabs where the geometric optics approximation applies. The influences of both plasma and collisional frequencies, as well as the width of the plasma slab, on the EM wave propagation characteristics are discussed. The results can help the further understanding of propagation behaviours of EM waves in nonuniform plasma, and applications of the interactions between EM waves and plasmas.

  20. Poda da haste principal e densidade de cultivo na produção e qualidade de frutos em híbridos de melão Pruning of main stem and plant density on yield and fruit quality of melon hybrids

    Directory of Open Access Journals (Sweden)

    Francisco Hevilásio F. Pereira

    2003-06-01

    Full Text Available Avaliou-se os efeitos da poda da haste principal e da densidade de cultivo sobre a produção e a qualidade de dois híbridos de melão. Os trabalhos foram desenvolvidos na ESAM em Mossoró-RN, de 01/06 a 11/08/98. Foram desenvolvidos dois experimentos, sendo um com e o outro sem poda da haste principal. Em cada um estudaram-se os híbridos Orange Flesh e Hy Mark e as densidades de cultivo de 20.000, 30.000, 40.000 e 50.000 plantas ha-1, arranjados em esquema fatorial 2 x 4. O delineamento experimental utilizado foi blocos casualizados com quatro repetições. Houve interação significativa entre a poda da haste principal e os híbridos para massa média dos frutos, relação de formato e sólidos solúveis totais e entre a poda da haste principal e a densidade de cultivo para o número de frutos totais e não-comercializáveis. Os híbridos Orange Flesh e Hy Mark, quando submetidos à poda, foram mais produtivos apresentando, em média, 25,96 Mg ha-1 de frutos comercializáveis. A produtividade e a massa média dos frutos diminuíram com o aumento da densidade de cultivo. O número de frutos totais e comercializáveis aumentaram em função da densidade de cultivo. O híbrido Orange Flesh, submetido à poda, apresentou a maior relação de formato, com índice de 1,09, enquanto o híbrido Hy Mark apresentou a menor, com índice de 1,04. O híbrido Hy Mark submetido à poda da haste principal apresentou o maior teor de sólidos solúveis totais (8,99%.Two field trials were carried out to evaluate the effect of pruning and planting density on yield and fruit quality of two melon hybrids. The work was done in Mossoró, Brazil, in the period of 06/01 to 08/11/98. The hybrids Orange flesh and Hy Mark were studied and the planting densities of 20,000; 30,000; 40,000 and 50,000 plants ha-1, in factorial outline 2 x 4. The experimental design was of randomized blocks, with four replications. There was significant interaction among pruning and hybrid

  1. Hybrid vehicles

    Energy Technology Data Exchange (ETDEWEB)

    West, J.G.W. [Electrical Machines (United Kingdom)

    1997-07-01

    The reasons for adopting hybrid vehicles result mainly from the lack of adequate range from electric vehicles at an acceptable cost. Hybrids can offer significant improvements in emissions and fuel economy. Series and parallel hybrids are compared. A combination of series and parallel operation would be the ideal. This can be obtained using a planetary gearbox as a power split device allowing a small generator to transfer power to the propulsion motor giving the effect of a CVT. It allows the engine to run at semi-constant speed giving better fuel economy and reduced emissions. Hybrid car developments are described that show the wide range of possible hybrid systems. (author)

  2. Pseudovector mesons, hybrids and glueballs

    CERN Document Server

    Burakovsky, L; Burakovsky, Leonid; Page, Philip R.

    2000-01-01

    We consider glueball- (hybrid) meson mixing for the low-lying four pseudovector states. The h_1'(1380) decays dominantly to K*K with some presence in rho pi and omega eta. The newly observed h_1(1600) has a D- to S-wave width ratio to omega eta which does not enable differentiation between a conventional and hybrid meson interpretation. We predict the decay pattern of the isopartner conventional or hybrid meson b_1(1650). A notably narrow s sbar partner h_1'(1810) is predicted.

  3. Desempenho de híbridos triplos de milho obtidos de top crosses em três locais do Estado de São Paulo Performance of maize triple cross-way hybrids in three environments in São Paulo State, Brazil

    Directory of Open Access Journals (Sweden)

    Maria Elisa Ayres Guidetti Zagatto Paterniani

    2006-01-01

    Full Text Available Com o objetivo de avaliar a capacidade de combinação e obter híbridos triplos superiores, 30 linhagens do programa de melhoramento de milho do Instituto Agronômico (IAC foram cruzadas em esquemas top crosses com dois testadores (híbridos simples experimentais. Os 60 híbridos top crosses, os testadores e duas testemunhas foram avaliados em dois ensaios (TC1 e TC2, sob delineamento de blocos casualizados com três repetições, na safra 2001/2002, em Campinas (Centro Experimental do IAC, Mococa (Pólo Regional de Desenvolvimento do Nordeste Paulista/APTA e Palmital (Pólo Regional de Desenvolvimento do Vale do Paranapanema/APTA. Os seguintes caracteres foram avaliados: altura da planta (AP e da espiga (AE, plantas acamadas e quebradas (Ac+Que, massa de espigas (ME e massa de grãos corrigida para 14% de umidade (MG. A capacidade de combinação foi estimada apenas para MG, de acordo com o Método 2 de Griffing. Pelos resultados constatou-se que tanto os efeitos da Capacidade Geral de Combinação (CGC como os da Capacidade Específica de Combinação (CEC foram importantes nesse dialelo. As linhagens que se destacaram quanto à CGC para MG nos três locais foram: L 126, L 111, IP 330 e SLP 103, podendo ser utilizadas para síntese de populações-base em programas de seleção recorrente e para programas de híbridos. Algumas linhagens tiveram elevadas estimativas de g i em locais específicos, como L 3 e L 161 em Palmital; IP 4035 em Mococa e AL 326 e L 14 em Campinas. Visando maximizar o rendimento potencial dos híbridos em cada ambiente, a escolha das linhagens poderá ser feita de acordo com a capacidade de combinação dentro de cada local.The objectives of this investigation were to study the combining ability of 30 lines of the maize breeding program of the Instituto Agronomico, São Paulo State, Brazil, in top crosses squemes, aiming at to identify lines for developing high yield triple cross hybrids with two testers (single cross

  4. Incidência de podridões do colmo, grãos ardidos e rendimento de grãos em híbridos de milho submetidos ao aumento na densidade de plantas Incidence of stalk rot, rot grains and grain yield of maize hybrids submitted to the increase in plant density

    Directory of Open Access Journals (Sweden)

    Ricardo Trezzi Casa

    2007-12-01

    Full Text Available A adequada combinação entre a escolha da densidade de plantas e do híbrido é um dos fatores que contribuem para o aumento da produtividade do milho. O objetivo deste trabalho foi avaliar o efeito do incremento na densidade de plantas sobre a incidência de podridões do colmo, de grãos ardidos e o rendimento de grãos de dois híbridos de milho contrastantes quanto a tolerância ao adensamento. O experimento foi conduzido em Lages, SC, nas safras agrícolas 2002/03 e 2003/04, em área de semeadura direta e monocultura, sob sucessão de cobertura morta constituída de aveia preta+ervilhaca. Estudou-se a combinação de dois fatores: híbrido e densidades, utilizando-se o delineamento experimental de blocos casualizados com parcela sub-dividida. Na parcela principal avaliaram os híbridos: Speed (simples, tolerante ao adensamento e AG 303 (duplo, intolerante ao adensamento. Nas sub-parcelas testaram-se cinco densidades de plantas: 25, 50, 75, 100 e 125 mil plantas ha-1. O aumento da densidade de plantas, proporcionou incremento linear na incidência das podridões do colmo e grãos ardidos para os dois híbridos e duas safras avaliadas. O fungo Colletotrichum graminicola foi o mais detectado em colmos doentes, seguido do Fusarium graminearum, F. verticillioides e Stenocarpella sp. Nos grãos ardidos, os fungos predominantes foram F. verticillioides, F. graminearum e Penicillium spp. O híbrido AG 303 demonstrou menor resposta no rendimento do que o híbrido Speed com o aumento da população de plantas. Não foi observada associação direta entre o maior rendimento de grãos do híbrido simples em estandes adensados e a menor incidência de doenças de colmo e de grãos ardidos.The combination between plant density and hybrid choice is an important factor to enhance maize grain yield. The objective of this work was to evaluate the increasing of plant density on the incidence of stalk rot, rot grains and grain yield of two maize hybrids with

  5. Effects of acoustic waves on pupas of Ceratitis capitata. (Wied., 1824) (Diptera: Tephritidae); Efeitos das ondas acusticas em pupas de Ceratitis capitata. (Wied., 1824) (Diptera: Tephritidae)

    Energy Technology Data Exchange (ETDEWEB)

    Barros, Adilson Camilo de

    2007-07-01

    The aim of this research has been to investigate the hypothesis that acoustic waves would provoke a measurable effect on a population of fruit flies, a treatment denominated sonication. Ionizing radiation, the causative agent for the treatment designated by irradiation has been used as a reference, as long as its effects on living beings and particularly on insects are widely known. This research also enquiries into the possible effects of acoustic waves and gamma rays. The experiments of sonication were carried out in the Laboratory of Entomology of the Instituto Biologico de Sao Paulo. The experiments of radiation were carried out in the Centro de Tecnologia das Radiacoes - IPEN, located within the campus of the University of Sao Paulo. It has been employed a Gamma cell source model 220 with average activity of 757.069 {+-} 293.484 curies (Ci) and an average doses rate of 3.106 {+-} 0.245 kilo grays per hour (kGy/h). Levels applied to the sonication treatment, in hertz and kilo Hertz were: 0 Hz (control) ; 5.0 Hz; 10.0 Hz; 20.0 Hz; 40.0 Hz; 60.0 Hz; 80.0 Hz; 1.0 k Hz; 2.0 k Hz; 10.0 k Hz; 15.0 k Hz e 20.0 k Hz. Irradiation doses applied in Grays were: 5.0 Gy; 7.5 Gy; 10.0 Gy; 12.5 Gy; 15 Gy; 50 Gy; 100 Gy; 150 Gy and 200 Gy. It has been used an acoustic tube made of glass - 40.6 cm in length and 9.1 cm in diameter - and sinusoidal waves originated from three acoustic sources, with response in decibels, which sound intensity varied from 93.60 {+-} 1.51 dB to 123.96 {+-} 0.23 dB. Final results have pointed to evidences that would justify the rejection of null hypothesis H{sub 0}, to which the average of the treatments due to acoustic waves do not differ significantly from each other.(author)

  6. Collapse of Electrostatic Waves in Magnetoplasmas

    DEFF Research Database (Denmark)

    Shukla, P. K.; Yu, M. Y.; Juul Rasmussen, Jens

    1984-01-01

    The two-fluid model is employed to investigate the collapse of electrostatic waves in magnetized plasmas. It is found that nonlinear interaction of ion cyclotron, upper-, and lower-hybrid waves with adiabatic particle motion along the external magnetic field can cause wave-field collapse....

  7. The generation and propagation of nonlinear waves in a reservoir; Geracao e propagacao de ondas nao-lineares em um reservatorio

    Energy Technology Data Exchange (ETDEWEB)

    Moreira, Roger Matsumoto; Mendes, Andre Avelino de Oliveira; Bacchi, Raphael David Aquilino [Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil). Escola de Engenharia. Lab. de Dinamica dos Fluidos Computacional (LabCFD)], e-mail: roger@vm.uff.br, e-mail: andreavelinoom@gmail.com, e-mail: raphael@esss.com.br

    2006-07-01

    The present work aims to model numerically the generation and propagation of waves in a reservoir, represented by a two-dimensional impermeable box, with a flat horizontal bottom and two vertical walls. The horizontal or vertical harmonic motion is imposed at the container, which is partially filled with water, with two possible initial conditions for the free surface: still water or a stationary sinusoidal wave. Two numerical methods are employed in the solution of the boundary value problem. The first is based on solving an integral equation that arises from Cauchy's integral theorem for functions of a complex variable. The transient nonlinear free surface flow is simulated using a boundary integral method. Numerical results are validated by comparing them with classical analytical solutions. The second method uses the commercial code ANSYS CFX with its homogeneous free surface model. In this case, results are compared with experiments done by Bredmose et al. (2003). In both models, interesting features at the free surface are obtained and discussed. (author)

  8. Photosynthetic characteristics of hybrid and conventional rice plants as a function of plant competition Características fotossintéticas de plantas de arroz híbridas e convencionais em função da intensidade de competição

    Directory of Open Access Journals (Sweden)

    G Concenço

    2011-12-01

    Full Text Available The objective of this work was to evaluate the characteristics related to the photosynthetic ability of hybrid and inbred rice varieties, as a way to assess which of the two presented higher potential to stand out under conditions of competition. The trial was set in a greenhouse in completely randomized block design and 2 x 6 factorial scheme with four replications. Factor A consisted of rice varieties (hybrid or inbred and factor B by competition levels. Treatments consisted in maintaining one plant of either BRS Pelota (inbred or Inov (hybrid variety at the center of the plot, under competition with 0, 1, 2, 3, 4 or 5 plants of the variety BRS Pelota at the periphery of the experimental unit, according to the treatment. Fifty days after emergence (DAE, sub-stomatal CO2 concentration (Ci - mmol mol-1, photosynthetic rate (A - mmol m-2 s-1 and CO2 consumed (DC - mmol mol-1 were quantified, as well as shoot dry mass(SDM.Hybrid plants present higher photosynthesis capacity than inbred plants, when competing with up to 3 times its own density. When under the same competitive intensity, hybrid plants surpass the inbred. However, it should be emphasized that, when in farm condition, the lower competitive capacity with weeds often attributed to the hybrid varieties, probably is due to their lower planting density, but if weed competition is kept at low levels, hybrid rice plants may perform in the same way or usually better than inbred plants.Objetivou-se com este estudo avaliar características relacionadas a capacidade fotossintética de variedades de arroz híbridas e convencionais, de forma a quantificar seu potencial de competição. O experimento foi instalado em casa de vegetação em delineamento experimental de blocos casualizados e esquema fatorial 2 x 6, com quatro repetições. O fator A consistiu de variedades de arroz (convencional e híbrida e o fator B de níveis de competição. Os tratamentos consistiram em manter uma planta da

  9. Training for Defense? From Stochastic Traits to Synchrony in Giant Honey Bees (<em>Apis dorsataem>

    Directory of Open Access Journals (Sweden)

    Gerald Kastberger

    2012-08-01

    Full Text Available In Giant Honey Bees, abdomen flipping happens in a variety of contexts. It can be either synchronous or cascaded, such as in the collective defense traits of shimmering and rearing-up, or it can happen as single-agent behavior. Abdomen flipping is also involved in flickering behavior, which occurs regularly under quiescent colony state displaying singular or collective traits, with stochastic, and (semi- synchronized properties. It presumably acts via visual, mechanoceptive, and pheromonal pathways and its goals are still unknown. This study questions whether flickering is preliminary to shimmering which is subject of the <em>fs em>(flickering-shimmering-transition> hypothesis? We tested the respective prediction that trigger sites (<em>ts> at the nest surface (where shimmering waves had been generated show higher flickering activity than the alternative non-trigger sites (<em>nts>. We measured the flickering activity of <em>ts>- and <em>nts>-surface bees from two experimental nests, before and after the colony had been aroused by a dummy wasp. Arousal increased rate and intensity of the flickering activity of both <em>ts>- and <em>nts> cohorts (P < 0.05, whereby the flickering intensity of <em>ts>-bees were higher than that of <em>nts>-bees (P < 0.05. Under arousal, the colonies also increased the number of flickering-active <em>ts>- and <em>nts>-cohorts (P < 0.05. This provides evidence that cohorts which are specialist at launching shimmering waves are found across the quiescent nest zone. It also proves that arousal may reinforce the responsiveness of quiescent curtain bees for participating in shimmering, practically by recruiting additional trigger site bees for expanding repetition of rate and intensity of shimmering waves. This finding confirms the <em>fs-transition> hypothesis and constitutes evidence that flickering is part of a basal colony-intrinsic information system

  10. RAPD markers utilization and other parameters in the determination of mango hybrids genitors Utilização de marcadores RAPD e outros parâmetros na determinação de genitores em híbridos de mangueira

    Directory of Open Access Journals (Sweden)

    Maria Cristina Rocha Cordeiro

    2006-08-01

    Full Text Available Actually mango (Mangifera indica, L. is considered one of the largest Brazilian fruitbusiness for the export market. Cultivar selection having high fruit quality is a fundamental step to obtain excellent results in this business. A mango breeding program based on intervarietal hybridization may produce new improved cultivars for mango growers. Mango hybrids have been obtained by controlled or open crosses. In the last one, it is important to identify the male parent because it is useful for the genetic cultivar history, thus it is important for planning further improvements. This work presents a parentage test using among others parameters RAPD (Random amplified Polymorphic DNA markers to estimate the male parent of the selected hybrids in an open cross plot by using five mango cultivars densely planted in a latin square design.Atualmente, o cultivo da mangueira (Mangifera indica, L. é considerado um dos maiores agronegócios frutícolas brasileiros para o mercado externo. A seleção de cultivares com elevada qualidade de frutos é uma etapa fundamental para o sucesso deste negócio. O melhoramento genético da mangueira, baseado em hibridações intervarietais, pode originar cultivares superiores aos padrões disponíveis no mercado, ofertando uma nova alternativa ao produtor. Híbridos de mangueira têm sido obtidos por meio de cruzamentos controlados ou abertos. Neste último, é importante identificar o genitor masculino visando a obter a história genética da cultivar além de ser importante no planejamento do melhoramento subseqüente. Este trabalho apresenta um teste de paternidade, utilizando, entre outros parâmetros, marcadores RAPD (Random Amplified Polymorphic DNA, para estimar o genitor masculino de híbridos selecionados em uma área de cruzamento aberto contendo cinco cultivares de manga plantadas em alta densidade, no delineamento experimental do quadrado latino.

  11. Stability of the hybrid epithelial/mesenchymal phenotype

    Science.gov (United States)

    Jolly, Mohit Kumar; Mooney, Steven M.; Celiktas, Muge; Hanash, Samir M.; Mani, Sendurai A.; Pienta, Kenneth J.; Ben-Jacob, Eshel; Levine, Herbert

    2016-01-01

    Epithelial-to-Mesenchymal Transition (EMT) and its reverse – Mesenchymal to Epithelial Transition (MET) – are hallmarks of cellular plasticity during embryonic development and cancer metastasis. During EMT, epithelial cells lose cell-cell adhesion and gain migratory and invasive traits either partially or completely, leading to a hybrid epithelial/mesenchymal (hybrid E/M) or a mesenchymal phenotype respectively. Mesenchymal cells move individually, but hybrid E/M cells migrate collectively as observed during gastrulation, wound healing, and the formation of tumor clusters detected as Circulating Tumor Cells (CTCs). Typically, the hybrid E/M phenotype has largely been tacitly assumed to be transient and ‘metastable’. Here, we identify certain ‘phenotypic stability factors’ (PSFs) such as GRHL2 that couple to the core EMT decision-making circuit (miR-200/ZEB) and stabilize hybrid E/M phenotype. Further, we show that H1975 lung cancer cells can display a stable hybrid E/M phenotype and migrate collectively, a behavior that is impaired by knockdown of GRHL2 and another previously identified PSF - OVOL. In addition, our computational model predicts that GRHL2 can also associate hybrid E/M phenotype with high tumor-initiating potential, a prediction strengthened by the observation that the higher levels of these PSFs may be predictive of poor patient outcome. Finally, based on these specific examples, we deduce certain network motifs that can stabilize the hybrid E/M phenotype. Our results suggest that partial EMT, i.e. a hybrid E/M phenotype, need not be ‘metastable’, and strengthen the emerging notion that partial EMT, but not necessarily a complete EMT, is associated with aggressive tumor progression. PMID:27008704

  12. Fotossíntese, remobilização de reservas e crescimento de grãos em dois híbridos de milho sob deficiência hídrica na fase de enchimento dos grãos Photosynthesis, reserves remobilization and grain growth of two maize hybrids submitted to water stress during the grain filling stage

    Directory of Open Access Journals (Sweden)

    Eduardo Caruso Machado

    1992-01-01

    Full Text Available Foram avaliados, em dois híbridos simples de milho (Zea mays L., Pioneer 3072 e IAC 701 x B, submetidos à deficiência hídrica, o comportamento da fotossíntese, da remobilização de N e de açúcares durante o período de crescimento dos grãos. As plantas foram cultivadas sob condições naturais, em doze tanques de alvenaria (4 m de comprimento x 0,5 m de largura x 0,6 m de profundidade contendo terra. A deficiência hídrica foi induzida entre o 5.º e o 15.º dia após a floração, suspendendo-se a irrigação. Sem deficiência hídrica, ambos os híbridos apresentaram comportamento semelhante quanto aos parâmetros avaliados. Sob deficiência hídrica, a remobilização de açúcares e de N, a partir dos órgãos vegetativos para os grãos, foi mais intensa que nas plantas-controle, sem deficiência hídrica, e mais acentuada, tanto em açúcares como em N, no híbrido IAC 701 x B. Sob deficiência hídrica, a taxa de fotossíntese diminuiu em ambos os híbridos, sobretudo no IAC 701 x B.Photosynthesis, nitrogen and sugar remobilization during the grain filling period were examined in two maize (Zea mays L. hybrids (Pioneer 3072 and IAC 701 x B submitted to water stress. The plants were grown under natural conditions in 12 boxes (4 m x 0,5 m x 0.6 m each containing soil. Water stress was imposed by with holding irrigation during the 5.th and 15.th days after anthesis. Both hybrids in control treatment (without water stress showed no differences in relation to the avaliated parameters. Under water stress the sugar and N remobilization from vegetative organs to the grains, were more intense than of the control plants. The sugar and N remobilization were larger in IAC 701 x B. The photosynthesis rates were reduced in both hybrids under water stress, but the reduction was larger in IAC 701 x B.

  13. Velocidade da onda de pulso, pressão arterial e adipocitocinas em adultos jovens: estudo do Rio de Janeiro Pulse wave velocity, blood pressure and adipocytokines in young adults: the Rio de Janeiro study

    Directory of Open Access Journals (Sweden)

    Oswaldo Luiz Pizzi

    2012-01-01

    Full Text Available FUNDAMENTO: Dados sobre a avaliação não invasiva vascular e suas relações com variáveis de risco cardiovascular são escassos em jovens. OBJETIVO: Avaliar a relação entre a velocidade de onda de pulso e a pressão arterial,variáveis antropométricas e metabólicas, incluindo as adipocitocinas, em indivíduos adultos jovens. MÉTODOS: Foram avaliados 96 indivíduos (51 homens do estudo do Rio de Janeiro, de 26 a 35 anos (média 30,09 ± 1,92. Foram obtidos a velocidade de onda de pulso (método Complior, pressão arterial, índice de massa corporal, glicose, perfil lipídico, leptina, insulina, adiponectina e o índice de resistência à insulina HOMA-IR. Os indivíduos foram estratificados em três grupos segundo o tercil da VOP para cada sexo. RESULTADOS: O grupo com maior tercil de VOP mostrou maiores médias de pressão arterial sistólica, pressão arterial diastólica, pressão arterial média, índice de massa corporal, insulina, HOMA-IR e menores médias de adiponectina, além de maiores prevalências de diabetes mellitus/intolerância à glicose e hiperinsulinemia. Houve correlação significativa e positiva da velocidade da onda de pulso com pressão arterial sistólica, pressão arterial diastólica, pressão de pulso e pressão arterial média, índice de massa corporal, e LDL-colesterol e negativa com HDL-colesterol e adiponectina. Em modelo de regressão múltipla, após ajuste do HDL-colesterol, LDL-colesterol e adiponectina para sexo, idade, índice de massa corporal e pressão arterial média, apenas o sexo masculino e a pressão arterial média mantiveram correlação significativa com a velocidade de onda de pulso. CONCLUSÃO: A velocidade de onda de pulso em adultos jovens mostrou relação significativa com variáveis de risco cardiovascular, destacando-se o sexo masculino e a pressão arterial média como importantes variáveis no seu determinismo. Os achados sugerem que a medida da VOP pode ser útil para a

  14. Velocidade da onda de pulso, pressão arterial e adipocitocinas em adultos jovens: estudo do Rio de Janeiro Pulse wave velocity, blood pressure and adipocytokines in young adults: the Rio de Janeiro study

    Directory of Open Access Journals (Sweden)

    Oswaldo Luiz Pizzi

    2013-01-01

    Full Text Available FUNDAMENTO: Dados sobre a avaliação não invasiva vascular e suas relações com variáveis de risco cardiovascular são escassos em jovens. OBJETIVO: Avaliar a relação entre a velocidade de onda de pulso e a pressão arterial,variáveis antropométricas e metabólicas, incluindo as adipocitocinas, em indivíduos adultos jovens. MÉTODOS: Foram avaliados 96 indivíduos (51 homens do estudo do Rio de Janeiro, de 26 a 35 anos (média 30,09 ± 1,92. Foram obtidos a velocidade de onda de pulso (método Complior, pressão arterial, índice de massa corporal, glicose, perfil lipídico, leptina, insulina, adiponectina e o índice de resistência à insulina HOMA-IR. Os indivíduos foram estratificados em três grupos segundo o tercil da VOP para cada sexo. RESULTADOS: O grupo com maior tercil de VOP mostrou maiores médias de pressão arterial sistólica, pressão arterial diastólica, pressão arterial média, índice de massa corporal, insulina, HOMA-IR e menores médias de adiponectina, além de maiores prevalências de diabetes mellitus/intolerância à glicose e hiperinsulinemia. Houve correlação significativa e positiva da velocidade da onda de pulso com pressão arterial sistólica, pressão arterial diastólica, pressão de pulso e pressão arterial média, índice de massa corporal, e LDL-colesterol e negativa com HDL-colesterol e adiponectina. Em modelo de regressão múltipla, após ajuste do HDL-colesterol, LDL-colesterol e adiponectina para sexo, idade, índice de massa corporal e pressão arterial média, apenas o sexo masculino e a pressão arterial média mantiveram correlação significativa com a velocidade de onda de pulso. CONCLUSÃO: A velocidade de onda de pulso em adultos jovens mostrou relação significativa com variáveis de risco cardiovascular, destacando-se o sexo masculino e a pressão arterial média como importantes variáveis no seu determinismo. Os achados sugerem que a medida da VOP pode ser útil para a

  15. Caracterização de frutos e poliembrionia em sementes de 'flying dragon' e de híbridos de porta-enxerto de citros Fruit characterization and seed polyembryony of 'flying dragon' and of hybrids citrus rootstocks

    Directory of Open Access Journals (Sweden)

    Rodrigo Amato Moreira

    2010-06-01

    Full Text Available A diversificação de porta-enxertos é uma realidade no momento atual da citricultura brasileira, devido aos inúmeros problemas fitossanitários que vêm sendo recorrentes. Neste contexto, algumas alternativas já são implementadas, como a utilização de alguns híbridos produzidos a partir do melhoramento convencional e por variedades já consagradas na citricultura. O presente trabalho foi realizado com o objetivo de caracterizar os frutos e avaliar a germinação e a poliembrionia das sementes de híbridos e alguns porta-enxertos convencionais. Para caracterização, foram colhidas, ao acaso, 12 amostras (frutos de cada porta-enxerto. Na avaliação do percentual de germinação, índice de velocidade de germinação e poliembrionia, foi utilizado o esquema fatorial 5 (porta-enxertos: híbridos UFLAD-2, UFLAD-3 e UFLAD-4, citrumeleiro 'Swingle' e o Poncirus trifoliata var. monstrosa 'Flying Dragon' x 2 (com e sem a remoção do tegumento da semente, sendo utilizadas quatro repetições. De acordo com os resultados obtidos, concluiu-se que: O tamanho do fruto não influenciou no rendimento de sementes. A remoção do tegumento acelerou o tempo de germinação das sementes em todos os porta-enxertos e proporcionou maior percentual de germinação. A poliembrionia não afetou o processo de germinação das sementes. Os porta-enxertos UFLAD-2, UFLAD-3, UFLAD-4 e citrumeleiro 'Swingle' apresentam potencial para serem utilizados como porta-enxertos na propagação de algumas variedades cítricas.The diversification of the rootstocks is a reality at the moment of the brazilian citriculture, due many problems that have been recurring. In this context some alternatives are already a reality as the use of some hybrids produced through conventional breeding and varieties already used in citrus. This work was carried out aiming to characterize the fruit and evaluate the germination and the polyembryony of the seed. For characterization were randomly

  16. Qualidade de melões (Cucumis melo L. var. cantalupensis Naud., híbrido Torreon, produzidos em hidroponia e armazenados em embalagens de polietileno Quality of Torreon hybrid melon fruits (Cucumis melo L. var. cantalupensis Naud. grown in hydroponic system and stored in polyethylene packaging

    Directory of Open Access Journals (Sweden)

    Auri Brackmann

    2006-08-01

    Full Text Available Este experimento teve por objetivos avaliar a permeabilidade de filmes de polietileno de diferentes espessuras e densidades ao O2 e ao CO2, a composição gasosa (O2, CO2 e etileno formada no interior das embalagens e a qualidade físico-química de melões (Cucumis melo L. var. cantalupensis Naud., híbrido Torreon, produzidos no sistema hidropônico "Nutrient Film Technique" (NFT e armazenados em embalagens de polietileno. Os tratamentos avaliados foram: (1 armazenamento refrigerado (sem uso de filme; (2 polietileno de baixa densidade (PEBD de 40µm; (3 PEBD de 60µm; (4 PEBD de 90µm; (5 polietileno de média densidade (PEMD de 40µm; (6 PEMD de 60µm. Os frutos permaneceram armazenados durante 25 dias a 3,8±0,2°C e por mais dois dias a 20°C. Os filmes de PEBD de 60 e 90µm e o PEMD de 60µm apresentaram menor permeabilidade ao CO2, mantendo as maiores concentrações de CO2 nas embalagens. O filme de PEBD de 90µm apresentou menor permeabilidade ao O2. A menor concentração de etileno foi obtida com o uso de PEBD de 40µm. O uso de filmes reduziu drasticamente a perda de massa dos frutos, quando comparados aos frutos não embalados. Os frutos acondicionados na embalagem de PEBD de 40µm mantiveram uma maior firmeza da polpa após o período de armazenamento, não diferindo estatisticamente dos frutos armazenados em PEMD de 40µm. Já a incidência de podridões foi significativamente menor nos frutos armazenados em PEMD de 60µm. De modo geral, os filmes avaliados mantêm semelhante a qualidade físico-química de melões híbrido Torreon produzidos hidroponicamente no sistema NFT.This study was carried out to evaluate the permeability to O2 and CO2, and gas composition (O2, CO2 and ethylene inside packages of different thickness and density polyethylene films. Moreover, the physical and chemical quality of Torreon hybrid melon fruit (Cucumis melo L. var. cantalupensis Naud. grown in a Nutrient Film Technique hydroponic system and stored

  17. Go hybrid: EM, crystallography, and beyond.

    Science.gov (United States)

    Lander, Gabriel C; Saibil, Helen R; Nogales, Eva

    2012-10-01

    A mechanistic understanding of the molecular transactions that govern cellular function requires knowledge of the dynamic organization of the macromolecular machines involved in these processes. Structural biologists employ a variety of biophysical methods to study large macromolecular complexes, but no single technique is likely to provide a complete description of the structure-function relationship of all the constituent components. Since structural studies generally only provide snapshots of these dynamic machines as they accomplish their molecular functions, combining data from many methodologies is crucial to our understanding of molecular function.

  18. Produção e qualidade da moranga híbrida em resposta a doses de nitrogênio Yield and quality of hybrid squash (pumpkin in response to nitrogen doses

    Directory of Open Access Journals (Sweden)

    Marinalva W Pedrosa

    2012-06-01

    Full Text Available Foram avaliados os efeitos de doses de N na produção e qualidade da moranga hibrida cv. Tetsukabuto (Takaima F1 em experimento na EPAMIG Centro Oeste, Prudente de Morais (MG, de 25/08 a 03/12/2008. Foram avaliadas cinco doses de nitrogênio (0; 37,5; 75; 150; 300 kg ha-1, na forma de uréia, divididas em quatro aplicações (30% no plantio, 20% aos 20 dias, 30% aos 40 dias e 20% aos 60 dias após a emergência, num delineamento experimental de blocos casualizados com quatro repetições. As doses de N influenciaram significativamente as características avaliadas. O número de frutos aumentou de 2.498 ao ponto de máximo de 6.794 frutos ha-1 com a aplicação de 219 kg ha-1 de N. O diâmetro e a espessura da polpa do fruto aumentaram de 14,97 e 2,33 cm, até atingirem os pontos máximos de 17,74 e 2,80 cm nas doses de 171 e 128 kg ha-1 de N, respectivamente. O teor de sólidos solúveis na polpa de frutos de moranga híbrida aumentou com o aumento das doses de N observando-se com a aplicação de 300 kg ha-1 de N teor de 8ºBrix. A produtividade de frutos foi também influenciada pelas doses de N estimando-se como valor máximo 11,55 t ha-1 de frutos com a aplicação de 300 kg ha-1 de N. A dose estimada de N relativa à máxima eficiência econômica foi obtida com a aplicação de 262 kg ha-1, considerando os preços de R$ 2,41 kg-1 de N e de R$ 560,00 t-1 de moranga.An experiment was carried out at EPAMIG Centro Oeste, Prudente de Morais, Minas Gerais state, Brazil, from August 25 to December 2, 2008, to evaluate the effects of N rates on production and quality of hybrid squash cv. Tetsukabuto (Takaima F1. The treatments were five N rates (0, 37.5, 75, 150, 300 kg ha-1, as urea, split in four applications (30% at planting date, 20% at 20 days, 30% at 40 days and 20% at 60 days after emergence in a randomized complete block design, with four replications. The N rates significantly affected the characteristics evaluated. The number of fruits

  19. Phoxonic Hybrid Superlattice.

    Science.gov (United States)

    Alonso-Redondo, Elena; Huesmann, Hannah; El Boudouti, El-Houssaine; Tremel, Wolfgang; Djafari-Rouhani, Bahram; Butt, Hans-Juergen; Fytas, George

    2015-06-17

    We studied experimentally and theoretically the direction-dependent elastic and electromagnetic wave propagation in a supported film of hybrid PMMA (poly[methyl-methacrylate])-TiO2 superlattice (SL). In the direction normal to the layers, this one-dimensional periodic structure opens propagation band gaps for both hypersonic (GHz) phonons and near-UV photons. The high mismatch of elastic and optical impedance results in a large dual phoxonic band gap. The presence of defects inherent to the spin-coating fabrication technique is sensitively manifested in the band gap region. Utilizing Brillouin light scattering, phonon propagation along the layers was observed to be distinctly different from propagation normal to them and can, under certain conditions (SL thickness and substrate elasticity), reveal the nanomechanical properties of the constituent layers. Besides the first realization of unidirectional phoxonic behavior, hybrid (soft-hard) periodic materials are a promising simple platform for opto-acoustic interactions and applications such as filters and Bragg mirrors.

  20. Variabilidade da espessura da lâmina foliar em duas espécies de Leucaena Benth. (Leguminosae e seus híbridos Variability of the foliar blade thickness in two species of Leucaena Benth. (Leguminosae and their hybrids

    Directory of Open Access Journals (Sweden)

    Paulo Emílio Kaminski

    1999-12-01

    Full Text Available A espessura da lâmina foliar foi analisada em duas espécies tetraplóides (2n=104 de Leucaena, L. leucocephala e L. diversifolia, e em híbridos entre ambas, num total de 25 plantas. Para cada planta, foram realizados cortes de 10 foliólulos. Os híbridos apresentaram valores médios para espessura da lâmina foliar intermediários (116,3 - 148,3µm entre os das espécies parentais (136,1-158,4µm e 169,2- 170,3µm para L.leucocephala e L.diversifolia, respectivamente e uma menor variabilidade individual.The foliar blade thickness was analyzed in two tetraploid (2n=104 species of Leucaena , L. leuccocephala and L. diversifolia and in hybrids between both, in a total of 25 plants. For each plant, 10 leaflets were measured. The hybrids presented intermediate average values of foliar blade (116.3 - 148.3µm in comparison with the parental species values (136.1-158.4µm and 169.2- 170.3µm for L. leucocephala and L. diversifolia, respectively and a smaller invidual variation.

  1. Análise dos traçados de ondas da agregação plaquetária em pacientes com doenças cardiovasculares em uso do ácido acetil salicílico comparados a doadores de sangue Analysis of the waves and aggregation patterns in patients with cardiovascular diseases in using acetylsalicylic acid compared blood donors

    Directory of Open Access Journals (Sweden)

    Patrícia S. M. Bernardi

    2004-12-01

    Full Text Available A agregação plaquetária avalia a função das plaquetas através de diferentes vias de ativação plaquetária in vitro, fornecendo traçados de ondas equivalentes à propriedade física dessa agregação. Sabendo-se que a aspirina acetila irrever­sivelmente a enzima cicloxigenase prevenindo a geração de tromboxana A2, potente ativador da agregação plaquetária, esta droga tem sido analisada há mais de trinta anos na clínica médica em pacientes com doenças cardiovasculares como uma potente droga antitrombótica. Foram nossos objetivos obter traçados de ondas correspondentes às fases da agregação plaquetária para nossa padronização utilizando nosso grupo controle de doadores de sangue e compará-las com nosso grupo estudo, frente a diferentes agentes agonistas em diferentes concentrações: ADP 1µM e 3µM; AA, 0,5mM; ADR, 0,05 mg/mL, 0,025 mg/mL e 0,010 mg/mL. Os grupos analisados foram constituídos por 41 cardíacos e 40 doadores de sangue considerados controle. Dos cardíacos, 33 faziam uso regular do AAS na concentração de 200 mg/dia e oito na concentração de 100 mg/dia, sendo todos considerados hipertensos. A padronização da agregometria estava na dependência do encontro de traçados correspondentes a ondas de agregação, sendo esses obtidos em porcentagem no tempo de cinco minutos estandartizados pelo aparelho utilizado. Comparando os resultados entre os pacientes e o grupo controle, foi possível observar que, na presença dos agentes agregantes ADP 1µM e ADP 3 µM, ADR 0,05 mg/mL, 0,025mg/mL e 0,010 mg/mL, os pacientes apresentaram 1ª onda, mas não 2ª onda. Por sua vez, no caso do AA 0,5 mM não houve o encontro de traçados de ondas.Platelet aggregation illustrates the function of the platelets by different ways of in vitro platelet activation providing wave traces equivalent to the physical proprieties of this aggregation. It is well known that aspirin irreversibly blocks the cyclooxygenase enzyme

  2. Comparison between two alternative approaches for the analysis of polarization evolution of EM waves in a nonuniform, fully anisotropic medium. A magnetized plasma; Paragone tra due metodi alternativi per l'analisi della polarizzazione di onde elettromagnetiche in un plasma magnetizzato

    Energy Technology Data Exchange (ETDEWEB)

    Segre, S. E. [ENEA, Div. Fusione, Centro Ricerche Frascati, Frascati, Rome (Italy)

    2001-07-01

    A comparison is made between two alternative approaches for the analysis of polarization evolution of em waves in a magnetized plasma. The two approaches are the Coupled Wave-Equation Formalism (CWF) and the Stokes Vector Formalism (SVF). After brief descriptions of the two formalisms the correspondence between them is spelled out. The two formalisms are then compared and their relative advantages and limitations are discussed. [Italian] Si fa un confronto tra due metodi alternativi per l'analisi della polarizzazione di onde elettromagnetiche in un plasma magnetizzato. I due metodi sono il formalismo delle equazioni accoppiate per le onde (Coupled Wave-equation Formalism) e il formalismo del vettore di Stokes (Stokes Vector Formalism). Dopo brevi descrizioni dei due formalismi, viene esplicitata la corrispondenza tra essi quindi i due formalismi vengono confrontati e si discutono i loro meriti e limiti relativi.

  3. Statistical Characterization of Electromagnetic Wave Propagation in Mine Environments

    KAUST Repository

    Yucel, Abdulkadir C.

    2013-01-01

    A computational framework for statistically characterizing electromagnetic (EM) wave propagation through mine tunnels and galleries is presented. The framework combines a multi-element probabilistic collocation method with a full-wave fast Fourier transform and fast multipole method accelerated surface integral equation-based EM simulator to statistically characterize fields from wireless transmitters in complex mine environments. 1536-1225 © 2013 IEEE.

  4. Commercial quality of different corn hybrids as a function of grain moisture content during the harvest Qualidade comercial de diferentes híbridos de milho em função do teor de água nos grãos durante a colheita

    Directory of Open Access Journals (Sweden)

    Luiz Fernando Pricinotto

    2012-06-01

    Full Text Available The objective this work was evaluate the commercial quality of grains of differents commercial corn hybrids as a function of grain moisture content during the harvest. The work was conducted in Astorga – PR, during the autumn/winter harvest of 2007 and the summer harvest of 2007/2008, evaluated three hybrids for harvest. The corn grain samples were collected in five distinguished periods and also in five replications, being underwent to moisture content determination at an oven heated to 103 ± 1 ºC for 72 h. The samples were passed through metal sieves of circular sieve of 4.76 mm in diameter and then the waste is manually separated portions of the impurities, broken grain and grain damaged by insects. The data were submitted to analyses of variance and regression under a arrangement completely randomized design, The percentages of impurities were higher in crop moisture content higher. While the percentage of broken grains were lower, regardless of the hybrid and the trial period. The percentage of grain damaged by insects raised linearly with the reduction of moisture in corn grains, in all hybrids and in two evaluation periods. The moisture content between 22.0% and 26.0% (w.b. proportionated the best quality of the corn grain, considered this humitidy band as the best moment to harvest grains. O objetivo deste trabalho foi avaliar a qualidade comercial dos grãos de diferentes híbridos comerciais de milho em função do teor de água nos mesmos durante a colheita. O trabalho foi conduzido em Astorga – PR, durante o período da safrinha de 2007 e da safra de verão de 2007/2008, sendo três híbridos avaliados em cada período. As amostras de grãos foram colhidas em cinco épocas distintas com cinco repetições e submetidas à determinação do teor de água pelo método da estufa a 103 ± 1 ºC por 72 h. Posteriormente, as amostras foram passadas por peneiras metálicas de crivo circular de 4,76 mm de diâmetro e, em seguida, os res

  5. Lente de contato de material híbrido em pacientes com ceratocone e astigmatismo miópico composto Hybrid material contact lens in keratoconus and myopic astigmatism patients

    Directory of Open Access Journals (Sweden)

    Fernando Leal

    2007-03-01

    óculos, exceto para a freqüência B (3 cpg, maior nos usuários de óculos. As aberrações de alta ordem analisadas apresentaram diminuição estatisticamente significante, quando comparados os pacientes sem e com uso de lentes de contato, com exceção da aberração esférica e do coma. CONCLUSÃO: A lente de contato de material híbrido, quando utilizada por portadores de ceratocone e astigmatismo miópico composto, propiciaram desempenho visual e conforto satisfatórios, em níveis que não diferiram, das lentes de contato rígidas-gás-permeáveis nos dois grupos de pacientes.PURPOSE: To evaluate comfort and visual performance in relation to two different used contact lens types: hybrid material (HM and rigid-gas-permeable (RGP, in patients with regular myopic astigmatism and with keratoconus. METHODS: A randomized, double masked, prospective study of 22 patients with the diagnosis of myopic astigmatism (8 with myopic astigmatism and 14 with keratoconus was conducted. Fifteen patients were female and 7 were male, and mean age was: 32.13 ± 8.12 years. In one of the eyes a rigid-gas-permeable contact lens was adapted (DK 30, and in the other a hybrid material contact lens was adapted (DK 23. All patients were submitted to the following tests: measurement of comfort level by means of the analogical visual scale, tear break-up time, best corrected visual acuity with the Bailey-Lovie scale adapted for 4 meters, functional acuity contrast test (FACT and wavefront analysis. RESULTS: In relation to comfort, there was no association with the evaluated contact lens type (p=0.350. There was a variation in comfort level during the first 7 days. The visual acuity increased between the 7th and the 15th day of adaptation. Visual acuity stabilized right after this period. The visual acuity did not show differences in relation to the studied lens type. It was verified that there was no difference in the tear break-up time (p=0.989 in relation to the studied lenses type and

  6. Hybrid Metaheuristics

    CERN Document Server

    2013-01-01

    The main goal of this book is to provide a state of the art of hybrid metaheuristics. The book provides a complete background that enables readers to design and implement hybrid metaheuristics to solve complex optimization problems (continuous/discrete, mono-objective/multi-objective, optimization under uncertainty) in a diverse range of application domains. Readers learn to solve large scale problems quickly and efficiently combining metaheuristics with complementary metaheuristics, mathematical programming, constraint programming and machine learning. Numerous real-world examples of problems and solutions demonstrate how hybrid metaheuristics are applied in such fields as networks, logistics and transportation, bio-medical, engineering design, scheduling.

  7. Perfil hormonal de Progesterona durante o ciclo Estral em novilhas Nelore confinadas com Diferentes Ondas de Crescimento Folicular Plasma Progesterone Level during the Estrous Cycle in Nelore Heifers Confined with Two, Three and Four Waves of Follicular Growth

    Directory of Open Access Journals (Sweden)

    Luciene Lomas Santiago

    2001-12-01

    Full Text Available Efetuaram-se coletas diárias de sangue, de 16 novilhas Nelore confinadas, para análise de progesterona plasmática pelo método de radioimunoensaio (RIA. Os dias analisados para progesterona foram o dia zero (estro e a cada três dias até o dia -1 e o dia zero. Os animais foram divididos em dois grupos: 1 com ciclo estral de 21 dias aproximadamente (novilhas que apresentaram duas e três ondas de crescimento folicular e 2 com ciclo estral superior a 25 dias (novilhas com quatro ondas de crescimento folicular. As concentrações médias de progesterona plasmática dos animais durante o ciclo estral diferiram entre os dois grupos, sendo superiores (4,27 ng/mL para os ciclos de maior duração. A concentração média de progesterona no ciclo de aproximadamente 21 dias foi de 2,54 ng/mL. Os resultados sugerem que as novilhas que apresentam maior duração do ciclo estral necessitam de tempo adicional para que seus folículos cheguem ao estádio pré-ovulatório, havendo, dessa maneira, prolongamento e aumento da secreção de progesterona.Blood were collected daily from 16 Nelore heifers confined, for radioimmunoassay (RIA.analyses of progesterone The plasma progesterone assay were at day zero (estrus and at each three days until the -1 and the day zero.again The animals were divided in two groups: 1 with regular estrous cycle of 21 days (heifers with two and three follicular growth waves and 2 with prolonged estrous cycle, greater than 25 days (heifers with four follicular growth waves. The mean plasma progesterone level from the animals during the estrous cycle differed between the two groups, being greater (4,27 ng/mL for the extended cycles.(above 25 days; 4,27 ng/mL than for the regular estrous cycle (21 days; 2,54 ng/mL. Results suggest that those heifers which showed an extended estrous cycles, needs an additional time for the follicles to each the pre-ovulatory stadium, resulting in prolonged and increased progesterone secretion.

  8. Classificação Macroscópica, identificação da microbiota fúngica e produção de aflatoxinas em híbridos de milho Macroscopic classification, identification of fungal microbiota and aflatoxins production in corn hybrids

    Directory of Open Access Journals (Sweden)

    Paulo Dilkin

    2000-03-01

    Full Text Available Com o objetivo de medir o potencial de resistência de 5 diferentes híbridos de milho, logo após a colheita, ao crescimento de fungos e produção de aflatoxinas (AFs, foram avaliados os seguintes parâmetros: 1 aspecto macroscópico dos grãos, sendo os grãos de cada híbrido classificados como íntegros, danificados por insetos (DI ou danificados por fungos (DF; 2 contaminação fúngica dos híbridos; 3 potencial para resistência à produção de AFs, através do cultivo de Aspergillus parasiticus, linhagem NRRL 2999, sobre grãos de cada híbrido estudado; 4 consumo de matéria seca dos híbridos pelo cultivo fúngico. Como resultado, observou-se que 38% do milho de todos os híbridos apresentaram comprometimento macroscópico, sendo 26,7% DI e 11,3% DF. Os híbridos recém-colhidos apresentaram contaminação fúngica por Penicillium sp. (14,3%; Aspergillus sp. (23,6% e Fusarium sp. (57,1%. O potencial de produzir AFs pelos diferentes híbridos em cultivos por 5 e 10 dias apresentou diferença somente com relação à aflatoxina G2 em cultivos por 5 dias. A média de consumo de matéria seca dos híbridos de milho foi de 1,25 e 2,69% submetidos ao cultivo de fungos por períodos de 5 e 10 dias, respectivamente.To determine the resistance of five different recently harvested corn hybrids to fungal growth and aflatoxins (AFs production the following parameters were measured: 1 Macroscopic aspect of the grain and each hybrid classified as whole, damaged by insects (DI or damaged by fungi (DF; 2 Fungal contamination of hybrids 3 Resistance to AFs production, through the culture of Aspergillus parasiticus, NRRL 2999 strain, on each hybrid grain studied and 4 Consumption of dry matter of hybrids by the fungal culture. It was observad that 38% of all corn hybrids had macroscopic damage, being 26.7% DI and 11.3% DF. The recently harvested hybrids showed fungal contamination by Penicillium sp. (14.3%; Aspergillus sp. (23.6% and Fusarium sp. (57

  9. Nitrogen fertilization impact on agronomic traits of maize hybrids released at different decades Impacto da fertilização nitrogenada sobre características agronômicas de híbridos de milho lançados em diferentes décadas

    Directory of Open Access Journals (Sweden)

    Luís Sangoi

    2001-05-01

    Full Text Available Genetic selection of maize hybrids is often conducted using high N rates during the breeding cycle. This procedure may either lead to the release of genotypes that present nitrogen luxury consumption or require a stronger N input to accomplish their yield potential. This work was carried out to evaluate the effects of N rates on grain yield and N use efficiency of hybrids cultivated in different decades in Southern Brazil. The trial was performed in Lages, Santa Catarina State. A split plot design was used. Hybrids Ag 12, Ag 28, Ag 303 and Ag 9012, released during the 60's, 70's, 80's and 90's, respectively, were evaluated in the main plots. Nitrogen rates equivalent to 0, 50, 100 and 200 kg ha-1 were side-dressed in the split-plots when each hybrid had six fully expanded leaves. Modern-day hybrid Ag 9012 had higher grain yield than hybrids of earlier eras, regardless of N rates. Under high doses of N, the older hybrids Ag 12 and Ag 28 took up more N and presented higher values of shoot dry matter at flowering than Ag 9012. Nonetheless, they set less grains per ear which contributed to decrease their grain yield and N use efficiency.Novos híbridos de milho são normalmente desenvolvidos utilizando-se altas doses de N durante o ciclo de seleção. Isto pode favorecer o lançamento de genótipos que apresentem consumo de luxo de N ou requeiram altas doses deste nutriente para expressarem o seu potencial produtivo. Este trabalho foi conduzido para avaliar os efeitos de doses de N sobre o rendimento de grãos e eficiência de uso do N de híbridos cultivados em diferentes épocas no sul do Brasil. O ensaio foi conduzido em Lages, Santa Catarina. Os híbridos Ag 12, Ag 28, Ag 303 e Ag 9012, lançados comercialmente nas décadas de 60, 70, 80 e 90, respectivamente, foram avaliados na parcela principal. Doses de N de 0, 50, 100 e 200 kg ha-1 foram aplicadas em cobertura nas subparcelas. O híbrido moderno Ag 9012 expressou maior rendimento de gr

  10. Hybrid intermediaries

    OpenAIRE

    Cetorelli, Nicola

    2014-01-01

    I introduce the concept of hybrid intermediaries: financial conglomerates that control a multiplicity of entity types active in the "assembly line" process of modern financial intermediation, a system that has become known as shadow banking. The complex bank holding companies of today are the best example of hybrid intermediaries, but I argue that financial firms from the "nonbank" space can just as easily evolve into conglomerates with similar organizational structure, thus acquiring the cap...

  11. Hybrid composites

    CSIR Research Space (South Africa)

    Jacob John, Maya

    2009-04-01

    Full Text Available effect was observed for the elongation at break of the hybrid composites. The impact strength of the hybrid composites increased with the addition of glass fibres. The tensile and impact properties of thermoplastic natural rubber reinforced short... panels made from conventional structural materials. Figure 3 illustrates the performance of cellular biocomposite panels against conventional systems used for building and residential construction, namely a pre- cast pre-stressed hollow core concrete...

  12. Controle genético e tolerância ao estresse de calor em populações híbridas e em cultivares de trigo Genetic control and tolerance to the heat stress in wheat hybrid population and cultivars

    Directory of Open Access Journals (Sweden)

    Moacil Alves de Souza

    2001-10-01

    Full Text Available O objetivo deste trabalho foi obter informações sobre o controle genético da produtividade de grãos de trigo sob condições de estresse de calor, o grau de tolerância ao estresse de calor de algumas cultivares e linhagens e a identificação de populações segregantes promissoras para a obtenção de linhagens adaptadas às condições da região central do Brasil. Foram avaliados 13 parentais e 40 populações provenientes de um dialelo parcial, nas gerações F1 e F2 em condições de campo, em Lavras e Patos de Minas, MG, com as semeaduras feitas no verão (fevereiro e no inverno (maio. Houve diferença de tolerância ao calor entre os parentais e entre as populações híbridas quanto ao caráter produção de grãos, e ambos os efeitos aditivos e não-aditivos foram importantes no controle genético deste caráter na presença ou ausência de calor. Apesar da ocorrência de interações populações x épocas de semeadura, a alta repetibilidade dos efeitos da capacidade geral de combinação permite inferir a possibilidade de acelerar os programas de melhoramento na região, efetuando-se a seleção tanto na época de verão quanto no inverno.The objective of this work was to get information about the genetic control of the grain yield under heat stress conditions, the tolerance of cultivar and the identification of promising segregation populations for selections of lines adapted to the conditions of the central region of Brazil. Thirteen parents and 40 populations in F1 and F2 generations derived by partial diallel crosses were evaluated. The experiments were conducted under field conditions in Lavras and Patos de Minas, MG, Brazil, sowing the seeds in the summertime (February and in the winter (May. There was difference of heat tolerance among parents and hybrid populations for grain yield character, and both additive and non-additive effects were important in the genetic control of grain yield character in the presence or absence

  13. Electromagnetic Waves

    DEFF Research Database (Denmark)

    This book is dedicated to various aspects of electromagnetic wave theory and its applications in science and technology. The covered topics include the fundamental physics of electromagnetic waves, theory of electromagnetic wave propagation and scattering, methods of computational analysis...

  14. Dry matter production and partitioning of maize hybrids and dwarf unes at four plant populations Produção e distribuição de matéria seca de híbridos e linhagens anãs de milho em quatro populações

    Directory of Open Access Journals (Sweden)

    Luis Sangoi

    1997-03-01

    Full Text Available This experiment was conducted in Ames, Iowa, USA, to compare dry matter accumulation patterns of maize genotypes contrasting in height and leafiness, and to test whether reduction in plant height an leaf number through the use of dwarfing genes or earliness can improve grain dry matter allocation. Five plant genotypes were tested: a full season hybrid adapted to central lowa (NK 4525, a short season hybrid adapted to northern Minnesota (C1070, and three dwarf lines (156-A, 302-E and I17- A. The dwarves contained, respectively, the homozygous, independent, recessive dwarfing genes d3, d1 and br2. Each genotype was sown at four plant populations: 25, 50, 75 and 100.000 plants. ha-1. Hybrids had the greatest rates of decrease in total biomass and grain dry matter per plant when population was increased, though they also had larger absolute values of these variables at any given density. Hybrids produced more grain dry matter per unit of leaf area, and a higher harvest index, regardless the plant population used. Reduction in plant height or leaf number did not improve maize efficiency in producing and partitioning dry matter to the grain.Este experimento foi conduzido em Ames, Iowa, Estados Unidos, tendo como objetivos comparar os padrões de produção e distribuição de matéria seca de genótipos de milho contrastantes quanto a estatura e número de folhas, e verificar se a redução nestas características, mediante a utilização de genes para nanismo ou cultivares precoces, pode aumentar a eficiência da planta em alocar matéria seca para a produção de grãos. Cinco genótipos foram testados: um híbrido de ciclo normal adaptado à região central de lowa (NK 4525, um híbrido de ciclo precoce adaptado à região norte do estado de Minnesota (C 1070, e três linhagens anãs (156-A, 302-E and 117-A, contendo os genes recessivos de nanismo d3, d1 and br2, respectivamente Cada genótipo foi semeado em quatro populações, equivalentes a 25

  15. Roll waves numerical simulation in closed channels

    OpenAIRE

    2013-01-01

    Resumo: Utilizando um método numérico especializado em problemas hiperbólicos chamado Riemann Solver, é feito um estudo para avaliar o processo de evolução de roll waves em canais fechados. Todo o estudo se baseia em fenômenos de propagação de ondas hiperbólicas do tipo ondas de gravidade. Foi utilizado um modelo unidimensional para representar a dinâmica das roll waves. Inicialmente foi feita uma análise das velocidades características envolvidas, a qual indicou, para o arranjo estratificado...

  16. Meiotic behavior in Panicum maximum Jacq. (Poaceae: Panicoideae: Paniceae): hybrids and their genitors = Comportamento meiótico em Panicum maximum Jacq. (Poaceae: Panicoideae: Paniceae): híbridos e seus progenitores

    OpenAIRE

    Cleide Pessim; Maria Suely Pagliarini; Liana Jank; Alice Maria de Souza Kaneshima; Andréa Beatriz Mendes Bonato

    2010-01-01

    Panicum maximum Jacq. is one of the most cultivated grasses in the world. The intraspecific hybridization breeding program underway at Embrapa Beef Cattle aims at combining several agronomic characteristics in a single plant with high seed production. Four intraspecific hybrids originated from the cross between sexual tetraploid female plants with apomictic tetraploid male plants, including the genitors, were cytologically evaluated in the meiotic process throughout conventional methodology. ...

  17. Online energy management for hybrid electric vehicles

    NARCIS (Netherlands)

    Kessels, J.T.B.A.; Koot, M.W.T.; Bosch, P.P.J. van den; Kok, D.B.

    2008-01-01

    Hybrid electric vehicles (HEVs) are equipped with multiple power sources for improving the efficiency and performance of their power supply system. An energy management (EM) strategy is needed to optimize the internal power flows and satisfy the driver's power demand. To achieve maximum fuel profits

  18. Online energy management for hybrid electric vehicles

    NARCIS (Netherlands)

    Kessels, J.T.B.A.; Koot, M.W.T.; Bosch, P.P.J. van den; Kok, D.B.

    2008-01-01

    Hybrid electric vehicles (HEVs) are equipped with multiple power sources for improving the efficiency and performance of their power supply system. An energy management (EM) strategy is needed to optimize the internal power flows and satisfy the driver's power demand. To achieve maximum fuel profits

  19. PROPAGATION OF ELECTROMAGNETIC WAVE IN THE THREE PHASES SOIL MEDIA

    Institute of Scientific and Technical Information of China (English)

    陈云敏; 边学成; 陈仁朋; 梁志刚

    2003-01-01

    The fundamental parameters such as dielectric permittivity and magnetic permeability are required to solve the propagation of electromagnetic wave (EM Wave) in the soil. Based on Maxwell equations, the equivalent model is proposed to calculate the dielectric permittivity of mixed soil. The results of calculation fit. the test data well and will provide solid foundation for the application of EM wave in the soil moisture testing, CT analyzing of soil and the inspecting of geoenvironment.

  20. Avaliação da silagem de diferentes híbridos de milho (Zea mays, L. por meio do desempenho de bezerros confinados em fase de crescimento Evaluation of silages of different corn hybrids (Zea mays, L. by feedlot performance of calves, during the growing phase

    Directory of Open Access Journals (Sweden)

    Joilmaro Rodrigo Pereira Rosa

    2004-08-01

    Full Text Available Objetivou-se avaliar, por meio do desempenho animal, silagens de três híbridos de milho (Zea mays, L.: Agroceres AG-5011, Braskalb XL-344 e Cargill C-806. Foram utilizados 27 machos, não-castrados, mestiços Nelore x Charolês, com idade média de 10 meses e peso médio inicial de 252 kg, confinados durante 84 dias, subdivididos em quatro períodos de 21 dias. As silagens dos híbridos testados corresponderam a 70% da matéria seca ofertada. Não houve interação do híbrido de milho testado com o período de avaliação em confinamento, para os parâmetros estudados. A dieta que incluiu a silagem do híbrido AG-5011 resultou em maior consumo voluntário médio diário de matéria seca, expresso por 100 kg de peso vivo e tamanho metabólico, e maior consumo médio diário de fibra em detergente ácido, expresso nas diferentes formas, em relação aos híbridos XL-344 e C-806, que, por sua vez, foram semelhantes entre si. As dietas que incluíram silagens dos híbridos AG-5011, XL-344 e C-806 apresentaram semelhanças quanto ao consumo voluntário de matéria seca, expresso em kg/animal/dia (6,73; 6,05; e 6,19, consumo médio diário de FDN, em kg/dia (3,054; 2,837; e 2,836, e energia digestível, expressa nas diferentes formas, ganho de peso médio diário, em kg/dia (1,283; 1,219; e 1,249, ganho em estado corporal, conversão alimentar (5,26; 4,98; e 4,97 e eficiência energética (14,02; 13,68; e 13,21. Os três híbridos são indicados como materiais genéticos de muito boa qualidade para produção de silagem, promovendo ganhos de peso diário superior a 1,2 kg/animal/dia, quando utilizados em dietas com relação volumoso:concentrado de 70:30.The objective of the experiment was to evaluate, through feedlot performance of calves, three corn hybrids (Zea mays, L.: Agroceres AG-5011, Braskalb XL-344 and Cargill C-806. For the evaluation, 27 Nellore x Charolais non-castrated crossbred males with average age of 10 months and average initial

  1. ENERGY MANAGEMENT STRATEGY FOR PARALLEL HYBRID ELECTRIC VEHICLES

    Institute of Scientific and Technical Information of China (English)

    Pu Jinhuan; Yin Chengliang; ZhangJianwu

    2005-01-01

    Energy management strategy (EMS) is the core of the real-time control algorithm of the hybrid electric vehicle (HEV). A novel EMS using the logic threshold approach with incorporation of a stand-by optimization algorithm is proposed. The aim of it is to minimize the engine fuel consumption and maintain the battery state of charge (SOC) in its operation range, while satisfying the vehicle performance and drivability requirements. The hybrid powertrain bench test is carried out to collect data of the engine, motor and battery pack, which are used in the EMS to control the powertrain. Computer simulation model of the HEV is established in the MATLAB/Simulink environment according to the bench test results. Simulation results are presented for behaviors of the engine, motor and battery. The proposed EMS is implemented for a real parallel hybrid car control system and validated by vehicle field tests.

  2. EMS – Elektron Musik Studion in Stockholm

    DEFF Research Database (Denmark)

    Groth, Sanne Krogh

    2016-01-01

    In 1964 the electronic music studio EMS, Stockholm opened as a conventional analogue studio. The primary intension with the institution was to build the world’s most advanced hybrid studio and to conduct an international research program into sound and sound perception. With financial support from...

  3. Ponderomotive Acceleration by Relativistic Waves

    CERN Document Server

    Lau, Calvin; Yeh, Po-Chun; Luk, Onnie; McClenaghan, Joseph; Ebisuzaki, Toshikazu; Tajima, Toshiki

    2014-01-01

    In the extreme high intensity regime of electromagnetic (EM) waves in plasma, the acceleration process is found to be dominated by the ponderomotive acceleration (PA). While the wakefields driven by the ponderomotive force of the relativistic intensity EM waves are important, they may be overtaken by the PA itself in the extreme high intensity regime when the dimensionless vector potential $a_0$ of the EM waves far exceeds unity. The energy gain by this regime (in 1D) is shown to be (approximately) proportional to $a_0^2$. Before reaching this extreme regime, the coexistence of the PA and the wakefield acceleration (WA) is observed where the wave structures driven by the wakefields show the phenomenon of multiple and folded wave-breakings. Investigated are various signatures of the acceleration processes such as the dependence on the mass ratio for the energy gain as well as the energy spectral features. The relevance to high energy cosmic ray acceleration and to the relativistic laser acceleration is conside...

  4. Composição química, digestibilidade e cinética de degradação ruminal das silagens de híbridos de girassol em diferentes épocas de semeadura Effects of sowing dates on chemical composition, digestibility and ruminal degradation kinetics of silages from sunflower hybrids

    Directory of Open Access Journals (Sweden)

    Renius Mello

    2006-08-01

    Full Text Available Objetivou-se estimar o valor nutritivo das silagens de quatro híbridos de girassol - Rumbosol-91 (forrageiro, M-734 (duplo-propósito, C-11 (duplo-propósito e BRS-191 (granífero - semeados em três épocas: outubro (antecipada, novembro (normal e dezembro (tardia - por meio de análises químicas, da digestibilidade e da cinética de degradação ruminal. O delineamento experimental foi em blocos ao acaso, com arranjo fatorial 4 x 3 (quatro híbridos x três épocas de semeadura e três repetições. Os teores de MS variaram de 23,2 a 43,0%; o pH, de 4,0 a 5,1; e o N-NH3%/NT, de 5,3 a 16,8%. Os teores de CZ oscilaram de 6,8 a 8,8% e aumentaram da semeadura em outubro para dezembro. O Rumbosol-91 apresentou teores menores de EE e maiores de N na parede celular, de N indisponível e de carboidratos totais (CHOT. Os teores de PB aumentaram e os de CHOT diminuíram de outubro para dezembro. A semeadura de novembro e o C-11 apresentaram menores teores de FDN, FDNcp e FDA. O C-11 semeado em novembro apresentou menor teor de LDA. A semeadura de outubro e o Rumbosol-91 tiveram maior proporção de LDA%/FDN. O Rumbosol-91 apresentou maior DIVMS e DIVFDN. A semeadura de novembro e os híbridos C-11 e M-734 apresentaram maior teor de NDT. O desaparecimento da MS pode ser representado por um único perfil de degradação. A proporção de FDN indegradável (I aumentou da semeadura em outubro para dezembro, com maiores valores para o BRS-191 semeado em dezembro. A extensão (Vf1 e a taxa (k1 de degradação da fração solúvel de rápida digestão diminuíram da semeadura em outubro para dezembro, com maiores valores para o Rumbosol-91 semeado em outubro. A relação entre análise química, digestibilidade, NDT e cinética de degradação ruminal foi melhor para os híbridos M-734 e C-11 semeados em novembro.The objective of this trial was to estimate chemical composition, digestibility and ruminal degradation kinetics of silages from four sunflower

  5. Rendimento de grãos de híbridos de milho em duas densidades de plantas com e sem a retirada dos perfilhos Grain yield of maize hybrids at two plant densities with and without tillers removal

    OpenAIRE

    Luís Sangoi; Amauri Schmitt; Alexandre Saldanha; Ciro Franco Fiorentin; Anderson José Pletsch; Jefferson Vieria; Maxciel Alcimar Gattelli

    2009-01-01

    O milho não possui um mecanismo efetivo de compensação de espaços vazios na lavoura. Desse modo, híbridos perfilhadores podem ser mais eficientes no aproveitamento dos recursos ambientais, principalmente sob baixas populações de plantas. Este trabalho foi conduzido com o objetivo de avaliar o desempenho agronômico de híbridos de milho cultivados em duas densidades de plantas, com e sem a presença de perfilhos. O ensaio foi implantado em Lages, Santa Catarina, nos anos agrícolas de 2005/2006 e...

  6. Nonlinear wave interactions in quantum magnetoplasmas

    CERN Document Server

    Shukla, P K; Marklund, M; Stenflo, L

    2006-01-01

    Nonlinear interactions involving electrostatic upper-hybrid (UH), ion-cyclotron (IC), lower-hybrid (LH), and Alfven waves in quantum magnetoplasmas are considered. For this purpose, the quantum hydrodynamical equations are used to derive the governing equations for nonlinearly coupled UH, IC, LH, and Alfven waves. The equations are then Fourier analyzed to obtain nonlinear dispersion relations, which admit both decay and modulational instabilities of the UH waves at quantum scales. The growth rates of the instabilities are presented. They can be useful in applications of our work to diagnostics in laboratory and astrophysical settings.

  7. Avaliação de cinco híbridos de milho (Zea mays, L. em diferentes estádios de maturação: 1. Produtividade, características morfológicas e correlações Evaluation of five corn hybrids (Zea mays, L. at different maturity stages: 1. Productivity, morphologic traits and correlations

    Directory of Open Access Journals (Sweden)

    Juliano Ricardo Fontanini Beleze

    2003-06-01

    Full Text Available Este trabalho foi conduzido para se avaliarem produtividade e as características morfológicas de cinco híbridos de milho Pioneer: superprecoce P32R21, os precoces P30R07, P3041, P30F33 e o semiprecoce P30F80, em cinco estádios de maturação. O delineamento utilizado foi de blocos ao acaso, com cinco tratamentos e quatro repetições. A colheita das amostras dos híbridos de milho foi adotada estimando-se cinco estádios de maturidade da planta: 30, 34, 38, 42 e 46% de matéria seca. Por ocasião da colheita, no primeiro estádio de maturação, foram tomados alguns parâmetros para avaliação, como altura da planta, altura inserção de espiga, peso da planta, diâmetro de colmo e número médio de espigas. Para cada estádio de maturação, procedeu-se à separação de colmo + bainha, lâmina foliar, grão, sabugo e palha. Os híbridos superprecoce P32R21 e o precoce P3041 apresentaram maiores peso, diâmetro de colmo e altura de planta. As produções de matéria seca (MS, massa verde, grãos, lâmina foliar e colmo + bainha, expressas em toneladas/ha, diferiram entre os híbridos avaliados e houve efeito de dias pós-plantio (DPP. O aumento na produção de MS verificado com o avanço do estádio de maturidade dos híbridos foi correlacionado positivamente com o aumento da produção de grãos (R² = 64,3%. A produção de MS correlacionou-se positivamente com a percentagem de espiga (R² = 56,0% e negativamente (R² = -56,7% com a percentagem de colmo + bainha (em relação a planta inteira.This study was conducted to evaluate productivity and morphologic traits of five hybrids of Pioneer corn: P32R21, P30R07, P3041, P30F33 and P30F80 at different maturity stages. The treatments were used in plots of 7 x 8 m in a randomized block design, with four replicates. The samples collected, of corn hybrid, were adopted trying to estimate phases of maturity of the plant (30, 34, 38, 42 and 46% of dry matter [DM]. In the first maturation stage

  8. Seleção de híbridos diplóides (AA de bananeira com base em três índices não paramétricos Selection of (AA diploid banana hybrids using three non-parametric indices

    Directory of Open Access Journals (Sweden)

    Lauro Saraiva Lessa

    2010-01-01

    Full Text Available Objetivou-se selecionar híbridos diplóides (AA de bananeira com base em três índices não paramétricos, a fim de orientar a seleção e aumentar o aproveitamento da variabilidade existente no Banco de Germoplasma de Bananeira da Embrapa Mandioca e Fruticultura Tropical. Foram avaliados 11 híbridos, no delineamento de blocos ao acaso, com quatro repetições. As parcelas constituíram-se de seis plantas, espaçadas de 2,5 m x 2,5 m, tendo na bordadura plantas da cultivar Pacovan. Tomaram-se dados dos seguintes caracteres: altura da planta, diâmetro do pseudocaule, número de filhos na floração, número de folhas na floração, ciclo da planta do plantio à emissão do cacho, presença de pólen, número de pencas, número de frutos, comprimento do fruto e resistência à Sigatoka-amarela. As médias desses 10 caracteres foram empregadas no cálculo dos índices multiplicativos, de soma de classificação e da distância genótipo-ideótipo. Os dois híbridos de melhor desempenho geral, o SH3263 e o 1318-01, foram classificados, respectivamente, em primeiro e segundo lugares pelos índices multiplicativos e de soma de classificação, enquanto o índice da distância genótipo-ideótipo os classificou em primeiro e quarto lugares respectivamente. Embora os três índices tenham demonstrado uma boa correspondência entre o desempenho geral dos híbridos e a sua classificação, os índices multiplicativo e de soma de classificação propiciaram classificação mais adequada desses híbridos.The objective of the present study was to select diploids (AA hybrids of banana based on three non-parametric indices as to guide the selection and increase the use of the variability present in the Banana Germplasm Bank of Embrapa Cassava and Tropical Fruits. Eleven hybrids were evaluated in random blocks with four replicates. The plots consisted of six plants spaced 2.5 m x 2.5 m whereas the border rows were from the Pacovan cultivar. The following

  9. The problem of the use the hybrid and photovoltaic systems in insular zones with climatic siversity in Madeira; A problematica da utilizacao de sistemas fotovoltaicos e hibridos em zonas insulares de diversidade climatica-ILHA da Madeira

    Energy Technology Data Exchange (ETDEWEB)

    Magro, J. C. E.

    2004-07-01

    Project PAUER contemplates the evaluation and utilization of renewable energy in insular zones with climatic diversity, situated on the Archipelago of Madeira. The project has three main areas of intervention: prospecting and evaluating energetic resources; creation of data bases of climatic data for application in energetic studies and other areas; the installation of twenty autonomous photovoltaic or hybrid systems in isolated localities. This communication presents some data from meteorological observations made up until the present date, following appropriate statistical analysis. Characteristics of some installed photovoltaic and hybrid systems as well as some of the principal problems encountered in the field are also given. (Author)

  10. Surface spin-electron acoustic waves in magnetically ordered metals

    CERN Document Server

    Andreev, Pavel A

    2015-01-01

    Degenerate plasmas with motionless ions show existence of three surface waves: the Langmuir wave, the electromagnetic wave, and the zeroth sound. Applying the separated spin evolution quantum hydrodynamics to half-space plasma we demonstrate the existence of the surface spin-electron acoustic wave (SSEAW). We study dispersion of the SSEAW. We show that there is hybridization between the surface Langmuir wave and the SSEAW at rather small spin polarization. In the hybridization area the dispersion branches are located close to each other. In this area there is a strong interaction between these waves leading to the energy exchange. Consequently, generating the Langmuir waves with the frequencies close to hybridization area we can generate the SSEAWs. Thus, we report a method of creation of the SEAWs.

  11. Wind-solar-battery hybrid system for electricity generation in remote areas. An alternative for conventional rural grid extension; Sistema hibrido eolico-solar-bateria para geracao de energia eletrica em locais remotos. Uma alternativa a extensao da rede convencional em meios rurais

    Energy Technology Data Exchange (ETDEWEB)

    Costa, Alexandre Carlos A.; Feitosa, Everaldo A.N. [Pernambuco Univ., Recife, PE (Brazil). Centro de Tecnologia e Geociencias. Centro Brasileiro de Energia Eolica

    1999-07-01

    This paper presents a hybrid system (installed at test area of the Brazilian Center for Eolian Energy - CBEE) consisting of wind turbine, photovoltaic panels and a battery bank, with a large reliability. This system is presented as an alternative to the extension of the conventional electric power distribution network through the Brazilian northeast area communities. Simulations of the system are presented, by using the HYBRID2 computer code, developed by the Massachusetts University jointly with researchers from the CBEE. A preliminary economic analysis is conducted by comparing the hybrid system parameters with parameters of the conventional electric power distribution network.

  12. Occurrence of Listeria monocytogenes in silages assessed by fluorescent in situ hybridization Ocorrência de Listeria monocytogenes em silagens avaliadas por meio da hibridação in situ fluorescente

    Directory of Open Access Journals (Sweden)

    M. Oliveira

    2008-02-01

    Full Text Available Avaliou-se a qualidade microbiológica da silagem produzida em Portugal e otimizaram-se alguns aspectos relacionados com a eficácia de detecção de Listeria monocytogenes mediante protocolo baseado na técnica de hibridação in situ fluorescente (FISH para detecção directa desse microrganismo em amostras de silagens. O protocolo foi aplicado a 74 amostras, em simultâneo com o método bacteriológico convencional. Este último permitiu a detecção de L. monocytogenes em 11 silos (15%. Por meio do protocolo FISH, observou-se que 22 silos (29,7% se encontravam contaminados. O método FISH apresentou precisão (77,0%, especificidade (92,5% e sensibilidade (72,7% elevadas, sendo adequado para a análise microbiológica presuntiva de silagens, uma vez que é um método rápido, fácl de realizar, sensível, reprodutível e pouco dispendioso.

  13. Consórcio sorgo-soja. I. Produção de forragem de cultivares de soja e híbridos de sorgo, consorciadas na linha, em dois sistemas de corte Sorghum-soybean intercropping. I. Production of forage of sorghum hybrids and soybean cultivars, intercropped on the line, in two cutting systems

    Directory of Open Access Journals (Sweden)

    Alessandro Guerra da Silva

    2000-12-01

    Full Text Available Visando selecionar cultivares de sorgo e soja de melhor rendimento forrageiro no consórcio, foi conduzido, em 1996/97, um ensaio no Departamento de Agricultura no Campus da Universidade Federal de Lavras, em Lavras, MG, em um Latossolo Roxo distrófico. O delineamento experimental utilizado foi o de blocos casualizados em esquema fatorial 2x4x4+4 com três repetições, sendo constituído por dois sistemas de corte (um único corte, rente ao solo, de ambas as culturas no estádio R5 da soja e um sistema de dois cortes: o primeiro feito aos 60 dias após a emergência a 30cm do solo e o segundo, após a rebrota das plantas, rente ao solo, na mesma época do corte do primeiro sistema, quatro cultivares de soja (CAC-1, Doko RC, UFV-16 e UFV-17 e quatro híbridos de sorgo forrageiro (AG 2002, AG 2006, BR 601 e CMSXS 756, e mais os quatros cultivares de sorgo em monocultivo. Os diferentes sistemas de corte alteraram significativamente os rendimentos de massa verde, matéria seca e proteína bruta total. A utilização do consórcio proporcionou maior rendimento de proteína bruta total, quando comparado ao monocultivo, sendo que as combinações UFV-16 x AG 2002 e CAC-1 x AG 2006 foram as de maior destaque para o sistema de um corte. No sistema de dois cortes, sobressaíram-se Doko RC x AG 2006 e BR 601 e Doko RC x BR 601. Em condição de monocultivo e consórcio, o híbrido de sorgo que proporcionou maior rendimento de massa verde, matéria seca e proteína bruta total foi o AG 2002.Aiming to select sorghum and soybean cultivars of best forage yield in the intercropping on the line, a trial was conducted in 1996/1997, at the Department of Agriculture on the campus of the Universidade Federal de Lavras, in Lavras, MG, Brazil, on a Distrophic Red Dusky Latosol. The experimental design utilized was that of randomized blocks in factorial scheme 2x4x4+4 with three replications, being made up of two cutting systems (a single cutting, close-cut to the

  14. Comparação das técnicas de captura de híbridos e PCR para a detecção de HPV em amostras clínicas Comparison of hybrid capture and PCR for HPV detection in clinical samples

    Directory of Open Access Journals (Sweden)

    Adriana Dalpicolli Rodrigues

    2009-12-01

    Full Text Available INTRODUÇÃO E OBJETIVOS: São conhecidos mais de 100 tipos de papilomavírus humano (HPV, dos quais 30 têm sido reportados em infecções anogenitais. A infecção tem importância clínica, pois alguns tipos virais estão associados a lesões que podem progredir para o câncer cervical. Sabe-se que os métodos moleculares são muito importantes para o diagnóstico dessa infecção. O objetivo do estudo é comparar a detecção de HPV de alto risco pelo método de captura híbrida 2 (CH2 com a detecção do vírus pela reação em cadeia da polimerase convencional (PCRc e em tempo real (PCR-TR. METODOLOGIA: Foram analisadas 56 amostras ectocervicais por CH2 e, após, por PCRc e PCR-TR. RESULTADOS: Ambas, PCRc e PCR-TR, apresentaram alta concordância entre si (95,1%, enquanto a comparação entre as PCRs e a CH2 mostrou concordância razoável entre os resultados (PCRc = 90,2% e PCR-TR = 87,8%. DISCUSSÃO E CONCLUSÃO: A CH é aceita para a detecção do HPV, entretanto pode ser menos sensível em comparação com as técnicas de PCR. A PCR-TR tem a vantagem sobre a PCRc em termos de velocidade, sendo também um pouco mais sensível. Devido à alta sensibilidade e à rapidez, os métodos de PCR poderiam ser usados para a triagem de HPV em amostras ectocervicais.INTRODUCTION AND OBJECTIVE: More than 100 types of human papillomaviruses (HPV are known, of which 30 have been reported in anogenital infections. The infection has clinical importance, inasmuch as some viral types are associated with lesions that can progress to cervical cancer. Molecular methods are considered an important tool for the diagnosis of this infection. The objective of this study was to compare the detection of high risk HPV using hybrid capture 2 with HPV detection by conventional and real time PCR. METHODOLOGY: 56 ectocervical samples were analyzed by hybrid capture and after that by conventional and real time PCR. RESULTS: Both PCR and RT-PCR showed a high degree of

  15. Relação entre a composição química e a degradabilidade in situ da matéria seca e da fibra em detergente neutro da fração volumosa de híbridos de milho Correlation between chemical composition and dry matter and neutral detergent fiber in situ degradation of corn hybrids bulky fraction

    Directory of Open Access Journals (Sweden)

    Luís Felipe Prada e Silva

    2000-02-01

    Full Text Available RESUMO - A composição química e a degradação in situ da matéria seca (MS e fibra em detergente neutro (FDN da fração volumosa (haste + folhas de 28 híbridos de milho, em 1996, e 21 híbridos, em 1997, foram estudadas para estabelecer as correlações existentes entre os parâmetros analisados. Dos 21 híbridos de milho selecionados em 1997, 13 fizeram parte do experimento em 1996. O modelo para avaliar a cinética de degradação in situ da MS (Mcdonald, 1981 e o modelo para analisar a cinética de degradação in situ da FDN (Mertens e Loften ,1980 foram usados. Os dados dos dois anos (1996, 1997 foram analisados em separado ou em conjunto. A degradação efetiva da MS da porção volumosa mostrou-se fortemente relacionada com os teores de fibra em detergente ácido (FDA e FDN, mas não com o teor de lignina. Nenhuma análise química se mostrou correlacionada com o tempo de retenção da FDN, ou com as taxas de degradação da fração insolúvel potencialmente degradável da MS ou da FDN. O teor de FDA mostrou-se altamente correlacionado (R²=0,86 com a degradabilidade efetiva da MS, quando os anos foram analisados em conjunto, e pode ser utilizado como indicador da degradação da MS da fração volumosa de híbridos de milho.ABSTRACT - The chemical composition and in situ dry matter (DM and neutral detergent fiber (NDF of bulky fraction (stall and sheets degradation of 28 corn hybrids in 1996, and 21 hybrids, in 1997, were studied to establish the correlation among the analyzed factors. From the 21 hybrids selected in 1997, 13 were part of the experiment in 1996. The model for the evaluation of in situ DM degradation kinetics (McDonald, 1981, and the model to analyze the in situ NDF degradation kinetics (Mertens and Loften, 1980 were used. Data from both 1966 and 1977 years were analyzed separated or as a set. The bulky fraction effective DM degradation was strongly correlated with the acid detergent fiber (ADF and NDF content, but

  16. Nonlinear lower hybrid modeling in tokamak plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Napoli, F.; Schettini, G. [Università Roma Tre, Dipartimento di Ingegneria, Roma (Italy); Castaldo, C.; Cesario, R. [Associazione EURATOM/ENEA sulla Fusione, Centro Ricerche Frascati (Italy)

    2014-02-12

    We present here new results concerning the nonlinear mechanism underlying the observed spectral broadening produced by parametric instabilities occurring at the edge of tokamak plasmas in present day LHCD (lower hybrid current drive) experiments. Low frequency (LF) ion-sound evanescent modes (quasi-modes) are the main parametric decay channel which drives a nonlinear mode coupling of lower hybrid (LH) waves. The spectrum of the LF fluctuations is calculated here considering the beating of the launched LH wave at the radiofrequency (RF) operating line frequency (pump wave) with the noisy background of the RF power generator. This spectrum is calculated in the frame of the kinetic theory, following a perturbative approach. Numerical solutions of the nonlinear LH wave equation show the evolution of the nonlinear mode coupling in condition of a finite depletion of the pump power. The role of the presence of heavy ions in a Deuterium plasma in mitigating the nonlinear effects is analyzed.

  17. Plasma waves

    CERN Document Server

    Swanson, DG

    1989-01-01

    Plasma Waves discusses the basic development and equations for the many aspects of plasma waves. The book is organized into two major parts, examining both linear and nonlinear plasma waves in the eight chapters it encompasses. After briefly discussing the properties and applications of plasma wave, the book goes on examining the wave types in a cold, magnetized plasma and the general forms of the dispersion relation that characterize the waves and label the various types of solutions. Chapters 3 and 4 analyze the acoustic phenomena through the fluid model of plasma and the kinetic effects. Th

  18. HYBRIDIZATION AND CHAMELEONIC JOURNALISM

    Directory of Open Access Journals (Sweden)

    Adriana Schryver Kurtz

    2016-12-01

    Full Text Available O texto aborda a crescente hibridização entre o Jornalismo e demais formatos midiáticos como resultado natural de um processo que já está na própria raiz da comunicação enquanto atividade histórica. A lógica interna e as potencialidades estéticas e discursivas do fenômeno são analisadas a partir das convergências entre jornalismo e cinema. Para tanto, utiliza o falso documentário Zelig (1983, texto fílmico de Woody Allen, híbrido por natureza, postulado como um microcosmo rico em pistas e sugestões para refletir sobre a fusão entre conteúdos informativos e não informativos.   PALAVRAS-CHAVE: Hibridização; Jornalismo; Cinema; Zelig.       ABSTRACT The text discusses the growing hybridization between journalism and other media formats as a natural result of a process that is already in the very root of communication while historical activity. The internal logic and the aesthetic and discursive potential of the phenomenon are analyzed through the convergences between journalism and cinema. Therefore, uses the mockumentary Zelig (1983, filmic text of Woody Allen, hybrid by nature, postulated as a microcosm rich in clues and suggestions to reflect about the merger between informative and uninformative content.      KEYWORDS: Hybridization; Journalism; Cinema; Zelig.     RESUMEN El texto aborda la creciente hibridación entre el periodismo y otros formatos de medios como um resultado natural de un proceso que ya está en la raíz misma de la comunicación mientras actividad histórica. Se analizan la lógica interna y el potencial estético y discursivo del fenómeno a través de las convergencias entre el periodismo y el cine. Para ello, utiliza el falso documental Zelig (1983, texto fílmico de Woody Allen, híbrido en su naturaleza, postulado como un microcosmos rico en pistas y sugerencias para reflexionar sobre la fusión entre contenidos informativos y no informativos.      PALABRAS CLAVE: Hibridaci

  19. Reference Gene Selection in the Desert Plant <em>Eremosparton songoricuem>m>

    Directory of Open Access Journals (Sweden)

    Dao-Yuan Zhang

    2012-06-01

    Full Text Available <em>Eremosparton songoricum em>(Litv. Vass. (<em>E. songoricumem> is a rare and extremely drought-tolerant desert plant that holds promise as a model organism for the identification of genes associated with water deficit stress. Here, we cloned and evaluated the expression of eight candidate reference genes using quantitative real-time reverse transcriptase polymerase chain reactions. The expression of these candidate reference genes was analyzed in a diverse set of 20 samples including various <em>E. songoricumem> plant tissues exposed to multiple environmental stresses. GeNorm analysis indicated that expression stability varied between the reference genes in the different experimental conditions, but the two most stable reference genes were sufficient for normalization in most conditions.<em> EsEFem> and <em>Esα-TUB> were sufficient for various stress conditions, <em>EsEF> and <em>EsACT> were suitable for samples of differing germination stages, and <em>EsGAPDH>and <em>Es>UBQ em>were most stable across multiple adult tissue samples. The <em>Es18Sem> gene was unsuitable as a reference gene in our analysis. In addition, the expression level of the drought-stress related transcription factor <em>EsDREB2em>> em>verified the utility of<em> E. songoricumem> reference genes and indicated that no single gene was adequate for normalization on its own. This is the first systematic report on the selection of reference genes in <em>E. songoricumem>, and these data will facilitate future work on gene expression in this species.

  20. Spheroidal Wave Functions in Electromagnetic Theory

    Science.gov (United States)

    Li, Le-Wei; Kang, Xiao-Kang; Leong, Mook-Seng

    2001-11-01

    The flagship monograph addressing the spheroidal wave function and its pertinence to computational electromagnetics Spheroidal Wave Functions in Electromagnetic Theory presents in detail the theory of spheroidal wave functions, its applications to the analysis of electromagnetic fields in various spheroidal structures, and provides comprehensive programming codes for those computations. The topics covered in this monograph include: Spheroidal coordinates and wave functions Dyadic Green's functions in spheroidal systems EM scattering by a conducting spheroid EM scattering by a coated dielectric spheroid Spheroid antennas SAR distributions in a spheroidal head model The programming codes and their applications are provided online and are written in Mathematica 3.0 or 4.0. Readers can also develop their own codes according to the theory or routine described in the book to find subsequent solutions of complicated structures. Spheroidal Wave Functions in Electromagnetic Theory is a fundamental reference for scientists, engineers, and graduate students practicing modern computational electromagnetics or applied physics.

  1. Dynamic control of asymmetric electromagnetic wave transmission by active chiral metamaterial

    Science.gov (United States)

    Chen, Ke; Feng, Yijun; Cui, Li; Zhao, Junming; Jiang, Tian; Zhu, Bo

    2017-02-01

    The asymmetric transmission of electromagnetic (EM) wave can be fully manipulated by chiral metamaterials, but little can achieve real-time and high efficient tunability due to challenges in practically deployable solutions. Here, we proposed a new scheme for flexibly and dynamically controlling the asymmetric EM wave transmission at microwave frequencies using planar metamaterial of deep subwavelength thickness incorporated with active components of PIN diodes. The asymmetric transmission of linearly polarized EM wave exhibits a high efficiency and a pronounced real-time continuous tunability controlled by the external stimulation of voltage biasing. In addition, the asymmetric transmission effect can be well preserved at large oblique incident angle up to ±70°. The design principle and EM performance are validated by both full wave simulations and experimental measurements. Such dynamically controllable chiral metamaterial may provide robust and flexible approach to manipulate EM wave propagation, as well as to facilitate EM device integration to create diverse functionalities.

  2. Dynamic control of asymmetric electromagnetic wave transmission by active chiral metamaterial

    Science.gov (United States)

    Chen, Ke; Feng, Yijun; Cui, Li; Zhao, Junming; Jiang, Tian; Zhu, Bo

    2017-01-01

    The asymmetric transmission of electromagnetic (EM) wave can be fully manipulated by chiral metamaterials, but little can achieve real-time and high efficient tunability due to challenges in practically deployable solutions. Here, we proposed a new scheme for flexibly and dynamically controlling the asymmetric EM wave transmission at microwave frequencies using planar metamaterial of deep subwavelength thickness incorporated with active components of PIN diodes. The asymmetric transmission of linearly polarized EM wave exhibits a high efficiency and a pronounced real-time continuous tunability controlled by the external stimulation of voltage biasing. In addition, the asymmetric transmission effect can be well preserved at large oblique incident angle up to ±70°. The design principle and EM performance are validated by both full wave simulations and experimental measurements. Such dynamically controllable chiral metamaterial may provide robust and flexible approach to manipulate EM wave propagation, as well as to facilitate EM device integration to create diverse functionalities. PMID:28202903

  3. Dynamic control of asymmetric electromagnetic wave transmission by active chiral metamaterial.

    Science.gov (United States)

    Chen, Ke; Feng, Yijun; Cui, Li; Zhao, Junming; Jiang, Tian; Zhu, Bo

    2017-02-16

    The asymmetric transmission of electromagnetic (EM) wave can be fully manipulated by chiral metamaterials, but little can achieve real-time and high efficient tunability due to challenges in practically deployable solutions. Here, we proposed a new scheme for flexibly and dynamically controlling the asymmetric EM wave transmission at microwave frequencies using planar metamaterial of deep subwavelength thickness incorporated with active components of PIN diodes. The asymmetric transmission of linearly polarized EM wave exhibits a high efficiency and a pronounced real-time continuous tunability controlled by the external stimulation of voltage biasing. In addition, the asymmetric transmission effect can be well preserved at large oblique incident angle up to ±70°. The design principle and EM performance are validated by both full wave simulations and experimental measurements. Such dynamically controllable chiral metamaterial may provide robust and flexible approach to manipulate EM wave propagation, as well as to facilitate EM device integration to create diverse functionalities.

  4. Heat Waves

    Science.gov (United States)

    Heat Waves Dangers we face during periods of very high temperatures include: Heat cramps: These are muscular pains and ... having trouble with the heat. If a heat wave is predicted or happening… - Slow down. Avoid strenuous ...

  5. Wave Star

    DEFF Research Database (Denmark)

    Kramer, Morten; Brorsen, Michael; Frigaard, Peter

    Denne rapport beskriver numeriske beregninger af forskellige flydergeometrier for bølgeenergianlæget Wave Star.......Denne rapport beskriver numeriske beregninger af forskellige flydergeometrier for bølgeenergianlæget Wave Star....

  6. Proposed observations of gravity waves from the early Universe via "Millikan oil drops"

    CERN Document Server

    Chiao, R Y

    2006-01-01

    Pairs of Planck-mass drops of superfluid helium coated by electrons (i.e., ``Millikan oil drops''), when levitated in a superconducting magnetic trap, can be efficient quantum transducers between electromagnetic (EM) and gravitational (GR) radiation. This leads to the possibility of a Hertz-like experiment, in which EM waves are converted at the source into GR waves, and then back-converted at the receiver from GR waves back into EM waves. Detection of the gravity-wave analog of the cosmic microwave background using these drops can discriminate between various theories of the early Universe.

  7. Proposed Observations of Gravitational Waves from the Early Universe via "MILLIKAN Oil DROPS"

    Science.gov (United States)

    Chiao, Raymond Y.

    Pairs of Planck-mass drops of superfluid helium coated by electrons (i.e. "Millikan oil drops"), when levitated in a superconducting magnetic trap, can be efficient quantum transducers between electromagnetic (EM) and gravitational (GR) radiation. This leads to the possibility of a Hertz-like experiment, in which EM waves are converted at the source into GR waves, and then back-converted at the receiver from GR waves into EM waves. Detection of the gravitational-wave analog of the cosmic microwave background using these drops can discriminate between various theories of the early Universe.

  8. Hybrid microelectronic technology

    Science.gov (United States)

    Moran, P.

    Various areas of hybrid microelectronic technology are discussed. The topics addressed include: basic thick film processing, thick film pastes and substrates, add-on components and attachment methods, thin film processing, and design of thick film hybrid circuits. Also considered are: packaging hybrid circuits, automating the production of hybrid circuits, application of hybrid techniques, customer's view of hybrid technology, and quality control and assurance in hybrid circuit production.

  9. Wave Dragon

    DEFF Research Database (Denmark)

    Kofoed, Jens Peter; Frigaard, Peter; Sørensen, H. C.

    1998-01-01

    This paper concerns with the development of the wave energy converter (WEC) Wave Dragon. This WEC is based on the overtopping principle. An overview of the performed research done concerning the Wave Dragon over the past years is given, and the results of one of the more comprehensive studies......, concerning a hydraulic evaluation and optimisation of the geometry of the Wave Dragon, is presented. Furthermore, the plans for the future development projects are sketched....

  10. Estudo da formação de ligações cruzadas por irradiação gama em membranas híbridas de Polissulfona Bisfenol-A e sílica precipitada Study of cross-linking reactions induced by gamma rays in hybrid membranes of Bisphenol-A-Polysulfone and precipitated silica

    Directory of Open Access Journals (Sweden)

    Acácio Antonio M. Furtado Filho

    2011-01-01

    Full Text Available No presente trabalho a polissulfona bisfenol-A (PSU foi sulfonada com o agente de sulfonação trimetil silil cloro sulfônico [(CH33SiSO3Cl], em solução homogênea de dicloroetano. A reação de sulfonação foi confirmada por titulação ácido-base e análises FTIR. As membranas híbridas foram obtidas por vazamento da solução polimérica da polissulfona bisfenol-A sulfonada (SPSU e sílica precipitada Tixosil® 333 em N-N-dimetilacetamida (DMAc, e a formação das ligações cruzadas foi estudada por irradiação. Foram utilizadas doses totais de 5 a 30 kGy de radiação gama, oriunda de uma fonte de 60Co. A absorção de água foi determinada pela variação percentual da massa da membrana seca e hidratada em água deionizada a 40 e 60 °C. A condutividade protônica das membranas na forma ácida foi obtida pela técnica da espectroscopia de impedância ac utilizando um potenciostato/galvanostato. As membranas híbridas reticuladas por irradiação apresentaram condutividade protônica próxima de 10-1 S.cm-1 a 100% RH e 80 °C. O desempenho eletroquímico, as estabilidades térmica e mecânica, e o baixo custo tornam a membrana SPSU híbrida reticulada um possível substituto da membrana Nafion nas células a combustível que usam eletrólito polimérico.In this work the bisphenol-A-polysulfone (PSF was sulfonated using trimethyl silyl chlorosulfonate [(CH33SiSO3Cl] as a mild sulfonating agent in a homogeneous solution of dichloroetane. The sulfonation reaction was confirmed by acid-base titration and FTIR-spectroscopy analysis. The hybrid membranes were obtained by casting the sulfonated bisphenol-A-polysulfone (SPSF and precipitated silica Tixosil® 333 solutions in N-N-dimethylacetamide. Cross-linking in the hybrid membranes was obtained by irradiation, with doses ranging from 5 to 30 kGy using gamma ray from a 60Co source. The water uptake and the swelling of the membranes were estimated by measuring the change in weight between

  11. Second harmonic wave generation from a nonlinear combination of volume wave and overdense plasma in negative permeability space

    Science.gov (United States)

    Iwai, Akinori; Nakamura, Yoshihiro; Sakai, Osamu

    2016-09-01

    We clarify the relation between second harmonic wave (SH wave) and plasma generation in various experimental conditions by detecting properties of propagating electromagnetic waves (EM waves). Plasma has a nonlinear reaction against EM wave, generating harmonic waves which depends on electron density ne. In the case with increased ne, EM wave comes to be prevented from going into plasma with negative permittivity ɛp. Double-split-ring resonators (DSRRs), one of metamaterials, make permeability μD negative. We have shown that EM wave being volume wave can propagate into the combination of overdense plasma and DSRRs because of real negative value refractive index N. In our previous paper, we have confirmed enhanced SH wave (4.9 GHz) generation in the composite with 2.45-GHz input. In this report, we show the dependence of the SH wave emission with plasma generation on plasma parameters and gas conditions of plasma. Furthermore, we show the phase change with N variation of the composite space in the case with various input power as the proof of the negative index state.

  12. Electromagnetic Waves

    DEFF Research Database (Denmark)

    This book is dedicated to various aspects of electromagnetic wave theory and its applications in science and technology. The covered topics include the fundamental physics of electromagnetic waves, theory of electromagnetic wave propagation and scattering, methods of computational analysis......, material characterization, electromagnetic properties of plasma, analysis and applications of periodic structures and waveguide components, etc....

  13. Wave phenomena

    CERN Document Server

    Towne, Dudley H

    1988-01-01

    This excellent undergraduate-level text emphasizes optics and acoustics, covering inductive derivation of the equation for transverse waves on a string, acoustic plane waves, boundary-value problems, polarization, three-dimensional waves and more. With numerous problems (solutions for about half). ""The material is superbly chosen and brilliantly written"" - Physics Today. Problems. Appendices.

  14. Numerical evaluation of external magnetic effect on electromagnetic wave transmission through reentry plasma layer

    Science.gov (United States)

    Zhao, Qing; Bo, Yong; Lei, Mingda; Liu, Shuzhang; Liu, Ying; Liu, Jianwei; Zhao, Yizhe

    2016-11-01

    Numerical study of electromagnetic (EM) wave transmission through the magnetized plasma layer is presented in this paper. The plasma parameters are derived from computational fluid dynamics simulation of the flow field around a blunt body flying at supersonic speed and serve as the background plasma condition in the numerical modeling for EM wave transmission. The EM wave is generated by our newly designed coaxial feed GPS patch antenna. The external magnetic field is applied and assumed to vary linearly as a function of wall distance. The effects of the external applied magnetic field and the plasma parameters on wave transmission are studied, and the results show that EM wave propagation in the non-uniformly magnetized plasma is a matter of impedance matching, and the EM wave transmission can be adjusted only when the proper strength of the magnetic field is applied.

  15. Renal and urinary findings in 20 patients with Williams-Beuren syndrome diagnosed by fluorescence in situ hybridization (FISH Achados renais e urinários em 20 pacientes com síndrome de Williams-Beuren diagnosticados pelo teste de hibridização in situ por fluoresceína (FISH

    Directory of Open Access Journals (Sweden)

    Sofia Mizuho Miura Sugayama

    2004-01-01

    Full Text Available PURPOSE: Williams-Beuren syndrome is a rare multiple anomalies/mental retardation syndrome caused by deletion of contiguous genes at chromosome region 7q11.23. The aim of this work was to determine the frequency and the types of renal and urinary tract anomalies in 20 patients with Williams-Beuren syndrome. METHODS: The fluorescence in situ hybridization test using a LSI Williams syndrome region DNA probe was performed for all 20 patients to confirm the diagnosis of Williams-Beuren syndrome. A prospective study was performed in order to investigate renal and urinary aspects using laboratory assays to check renal function, ultrasonography of the kidneys and urinary tract, voiding cystourethrogram and urodynamics. RESULTS: Deletion of the elastin gene (positive fluorescence in situ hybridization test was found in 17 out of 20 patients. Renal alterations were diagnosed in 5 of 17 (29% the patients with the deletion and in 1 of 3 patients without the deletion. Fourteen patients with the deletion presented dysfunctional voiding. Arterial hypertension was diagnosed in 3 patients with deletions and 1 of these presented bilateral stenosis of the renal arteries. CONCLUSIONS: Due to the high incidence of renal and urinary abnormalities in Williams-Beuren syndrome, performing a systematic laboratory and sonographic evaluation of the patients is recommended.OBJETIVO: A síndrome de Williams-Beuren é uma rara síndrome de deleção de genes contíguos que cursa com múltiplas anomalias congênitas, deficiência mental e anomalias renais e urinárias. O objetivo deste trabalho foi determinar a freqüência e os tipos de anomalias renais e urinárias em 20 pacientes com síndrome de Williams-Beuren diagnosticados pelo teste de hibridização in situ por fluorescência. MÉTODOS: Estudou-se prospectivamente os aspectos renais e urinários através de avaliação laboratorial da função renal, ultrassonografia de rins e vias urinárias, uretrocistografia

  16. Parâmetros dendrométricos e correlações com propriedades tecnológicas em um híbrido clonal de Eucalyptus urophylla x Eucalyptus grandis Dendrometric parameters and correlations with technological properties in a clonal hybrid of Eucalyptus urophylla x Eucalyptus grandis

    Directory of Open Access Journals (Sweden)

    Fabricio Gomes Gonçalves

    2010-10-01

    Full Text Available A qualidade da madeira aparentemente está associada às características dendrométricas, que por sua vez são influenciadas pelas condições de crescimento. Os objetivos deste estudo foram a caracterização dendrométrica e a realização de correlações de Pearson entre alguns parâmetros tecnológicos da madeira do híbrido clonal de Eucalyptus urophylla x Eucalyptus grandis sob três estratos silviculturais. Os dados dendrométricos foram analisados mediante a análise de regressão. Os resultados mostraram que o híbrido apresenta comportamento similar ao das demais madeiras da mesma espécie que cresceram em outras regiões, destacando-se a espessura do alburno no E1 (talhadia simples, 70 meses e com um desbaste, com pouca variação ao longo do fuste. Todas as árvores apresentaram, em geral, baixa conicidade ao longo do fuste e baixo volume de casca entre os estratos. Na correlação de Pearson foram avaliados entre si nove parâmetros dendrométricos, sete físicos e três mecânicos, longitudinalmente em seções de 3 m e na posição medula-casca nas duas primeiras toras. Os coeficientes encontrados demonstram haver fortes correlações entre as propriedades, destacando-se a densidade básica em relação às demais características e o coeficiente de anisotropia, ambas importantes no processo de desdobro e secagem da madeira. Não houve correlações significativas nas contrações lineares e volumétricas ao longo do comprimento do fuste. A variação radial mostrou boas correlações entre todas as propriedades mecânicas avaliadas nas duas primeiras toras. Em contrapartida, as propriedades físicas avaliadas na posição radial não apresentaram correlações significativas.Wood quality is apparently associated with the dendrometric characteristics that are influenced by growth conditions. The aim of this study was the dendrometric characterization and realization of Pearson Correlations among some technological parameters in

  17. Resistência do cafeeiro a nematóides: I - Testes em progênies e híbridos, para Meloidogyne exigua Coffee breeding for resistance to Meloidogyne exigua: I - Screening test using arabica progenies and interespecific hybrids

    Directory of Open Access Journals (Sweden)

    L. C. Fazuoli

    1977-01-01

    Full Text Available Procurou-se identificar fontes de resistência ao nematóide Meloidogyne exígua em cafeeiros derivados de híbridos interespecíficos e em progênies de café arábica oriundas da Etiópia, em experimentos estabelecidos em duas localidades. A infestação foi feita por dois processos usados com freqüência nesse tipo de trabalho. As avaliações do grau de ataque foram feitas quatro e 12 meses após a infestação, em Campinas e Ribeirão Preto, respectivamente, adotando-se escala variando de zero, para ausência de galhas, a cinco pontos para grande intensidade de ataque. Verificou-se que a leitura feita aos quatro meses é tão eficiente quanto aos 12 meses, indicando a possibilidade de abreviar consideravelmente a duração dessas avaliações. Notou-se, no experimento de Ribeirão Preto, uma redução de aproximadamente 8% no crescimento das mudas infestadas e verificou-se, também, uma redução de 11,5% e 12% nos pesos verde e seco das plantas, devido ao ataque do nematóide. De 1.692 plantas examinadas nos dois experimentos, selecionaram-se 106 (6,3%, caracterizadas pela ausência de galhas. As populações derivadas dos híbridos entre Coffea arabica e C. canephora revelaram-se mais promissoras, contribuindo com maior número de plantas resistentes. As plantas do experimento instalado em Campinas foram inoculadas também com a raça II de Hemileia vastatrix para o estudo da resistência conjunta aos dois patógenos. Essas seleções, em número de 38, representam valioso material para o programa de melhoramento do cafeeiro.Two coffee screening tests were undertaken in order to find out sources of resistance to the nematode M. exigua. Arabica progenies from Ethiopia origin and advanced popu-lations derived from interspecific crosses (Coffea arabica x C. canephora and C. arabica x C. dewevrei were evaluated. A five point scale (0 point to the roots without galls and 5 points to severely attacked roots was used for determination of the

  18. Surface wave modelling and simulation for wave tanks and coastal areas

    OpenAIRE

    Groesen, van, E.; Bunnik, T.; Andonowati

    2011-01-01

    For testing ships and offshore structures in hydrodynamic laboratories, the sea and ocean states should be represented as realistic as possible in the wave tanks in which the scaled experiments are executed. To support efficient testing, accurate software that determines and translates the required wave maker motion into the downstream waves is very helpful. This paper describes an efficient hybrid spatial-spectral code that can deal with simulations above flat and varying bottom. The accurac...

  19. Synthesis, Crystal Structure and Luminescent Property of Cd (II Complex with <em>N-Benzenesulphonyl-L>-leucine

    Directory of Open Access Journals (Sweden)

    Xishi Tai

    2012-09-01

    Full Text Available A new trinuclear Cd (II complex [Cd3(L6(2,2-bipyridine3] [L =<em> Nem>-phenylsulfonyl-L>-leucinato] has been synthesized and characterized by elemental analysis, IR and X-ray single crystal diffraction analysis. The results show that the complex belongs to the orthorhombic, space group<em> Pem>212121 with<em> aem> = 16.877(3 Å, <em>b> em>= 22.875(5 Å, <em>c em>= 29.495(6 Å, <em>α> em>= <emem>= <emem>= 90°, <em>V> em>= 11387(4 Å3, <em>Z> em>= 4, <em>Dc>= 1.416 μg·m−3, <emem>= 0.737 mm−1, <em>F> em>(000 = 4992, and final <em>R>1 = 0.0390, <em>ωR>2 = 0.0989. The complex comprises two seven-coordinated Cd (II atoms, with a N2O5 distorted pengonal bipyramidal coordination environment and a six-coordinated Cd (II atom, with a N2O4 distorted octahedral coordination environment. The molecules form one dimensional chain structure by the interaction of bridged carboxylato groups, hydrogen bonds and p-p interaction of 2,2-bipyridine. The luminescent properties of the Cd (II complex and <em>N-Benzenesulphonyl-L>-leucine in solid and in CH3OH solution also have been investigated.

  20. HETEROSE EM ARROZ IRRIGADO HETEROSIS IN IRRIGATED RICE

    Directory of Open Access Journals (Sweden)

    Elcio Perpétuo Guimarães

    2007-09-01

    Full Text Available

    Com o objetivo de medir a magnitude da heterose, heterobeltiose e heterose padrão para oito características em híbridos de arroz (<em>Oryza> <em>sativa> L. irrigado, foram avaliados 19 híbridos resultantes de cruzamentos entre duas linhagens A e 17 linhagens restauradoras, em experimentos conduzidos em Goianira (GO, no delineamento de blocos ao acaso com três repetições. Observou-se a existência de variabilidade genética entre as restauradoras para a produtividade de grãos. Todos os híbridos apresentaram heterose positiva para produtividade de grãos e os de maiores valores tiveram heterose positiva para diferentes componentes de produtividade, indicando que, para esta característica, a heterose é o resultado da interação de heteroses dos componentes de produtividade. Para perfilhos e panículas por metro quadrado, os valores positivos e negativos foram semelhantes em números e magnitude nos três tipos de heterose. O comprimento das panículas e a massa de 100 grãos foram as variáveis que mais contribuíram para a heterose em produtividade de grãos. Todos os híbridos foram mais precoces que os genitores. A heterose para altura de plantas não alterou significativamente o porte dos híbridos porque todos os genitores eram baixos. A hibridação, mesmo entre cultivares do grupo Indica, aumentou a esterilidade de grãos.

    PALAVRAS-CHAVE: <em>Oryza> <em>sativa>; arroz híbrido; produtividade de grãos; componentes de rendimento.

    The objective of this study was to evaluate heterosis, heterobeltiosis and standard heterosis for eight characteristics of irrigated rice (<em>Oryza> <em>sativa> L. hybrids derivated from crosses among two A lines and 17 restorers lines. Field trials were conducted in Goinira, Goiás, Brazil. The experimental

  1. EMS磁悬浮列车的零电流型永磁电磁混合磁铁设计技术研究%Design of Zero-Power Hybrid Magnet with Permanent Magnets and Electromagnets in EMS Maglev Vehicles

    Institute of Scientific and Technical Information of China (English)

    李云钢; 张晓; 程虎; 刘恒坤

    2011-01-01

    针对EMS磁悬浮列车的零电流型永磁电磁混合磁铁,研究其永磁体和电磁线圈结构参数的设计方法.永磁体安装在磁轭部位,其截面积不受磁极面积的限制,研究得出永磁体的厚度与其截面积的约束关系,并给出永磁重量最小化的设计方法.根据最大平衡安匝数要求,研究得出相对于纯电磁铁,混合磁铁的电磁线圈匝数可减半.由于混合磁铁的可控性能低于纯电磁铁,基于可控性要求,给出修正永磁体的结构参数的方法.最后给出一个实例,将1t负载悬浮在8mm间隙内,所需永磁体仅为6.4 kg.%To design the zero-power hybrid magnet with permanent magnets and electromagnets for EMS maglev vehicles, the structural parameters of its permanent magnets and electromagnets were researched on. The permanent magnet was located at die middte of the yoke, which made its sectional area independent from the area of the pole. The restriction between the thickness and the area of the permanent magnet was presented, and the method of designing the permanent magnet with minimum mass was given. According to the requirements of the maximum balance ampere-turn, it was concluded that the ampere-turn of the hybrid magnet can be reduced to half of that of the pure electromagnet. It was shown that the controllability of the hybrid magnet is always weaker than that of the pure electromagnet, and then a revision of the design for the permanent magnet was proposed based on the requirement of the controllability. Finally, a design example of the hybrid magnet was presented with 11 load suspending at 8 mm, and the mass of the permanent magnet was only 6.4 kg.

  2. Hybrid Gear

    Science.gov (United States)

    Handschuh, Robert F. (Inventor); Roberts, Gary D. (Inventor)

    2016-01-01

    A hybrid gear consisting of metallic outer rim with gear teeth and metallic hub in combination with a composite lay up between the shaft interface (hub) and gear tooth rim is described. The composite lay-up lightens the gear member while having similar torque carrying capability and it attenuates the impact loading driven noise/vibration that is typical in gear systems. The gear has the same operational capability with respect to shaft speed, torque, and temperature as an all-metallic gear as used in aerospace gear design.

  3. Hybrid Qualifications

    DEFF Research Database (Denmark)

    has turned out as a major focus of European education and training policies and certainly is a crucial principle underlying the European Qualifications Framework (EQF). In this context, «hybrid qualifications» (HQ) may be seen as an interesting approach to tackle these challenges as they serve «two...... masters», i.e. by producing skills for the labour market and enabling individuals to progress more or less directly to higher education. The specific focus of this book is placed on conditions, structures and processes which help to combine VET with qualifications leading into higher education...

  4. Tropical Cyclogenesis in a Tropical Wave Critical Layer: Easterly Waves

    Science.gov (United States)

    Dunkerton, T. J.; Montgomery, M. T.; Wang, Z.

    2009-01-01

    The development of tropical depressions within tropical waves over the Atlantic and eastern Pacific is usually preceded by a "surface low along the wave" as if to suggest a hybrid wave-vortex structure in which flow streamlines not only undulate with the waves, but form a closed circulation in the lower troposphere surrounding the low. This structure, equatorward of the easterly jet axis, is identified herein as the familiar critical layer of waves in shear flow, a flow configuration which arguably provides the simplest conceptual framework for tropical cyclogenesis resulting from tropical waves, their interaction with the mean flow, and with diabatic processes associated with deep moist convection. The recirculating Kelvin cat's eye within the critical layer represents a sweet spot for tropical cyclogenesis in which a proto-vortex may form and grow within its parent wave. A common location for storm development is given by the intersection of the wave's critical latitude and trough axis at the center of the cat's eye, with analyzed vorticity centroid nearby. The wave and vortex live together for a time, and initially propagate at approximately the same speed. In most cases this coupled propagation continues for a few days after a tropical depression is identified. For easterly waves, as the name suggests, the propagation is westward. It is shown that in order to visualize optimally the associated Lagrangian motions, one should view the flow streamlines, or stream function, in a frame of reference translating horizontally with the phase propagation of the parent wave. In this co-moving frame, streamlines are approximately equivalent to particle trajectories. The closed circulation is quasi-stationary, and a dividing streamline separates air within the cat's eye from air outside.

  5. Key Aspects of Wave Energy

    DEFF Research Database (Denmark)

    Margheritini, Lucia; Nørgaard, Jørgen Harck

    2012-01-01

    Diversification of renewable energy sources is fundamental to ensure sustainability. In this contest, wave energy can provide a substantial contribution as soon as the sector breaks into the market. In order to accelerate shift from a technology to a market focus and reduce technical and non...... be used as a breakwater therefore providing a solid structure for harbor protection; the Wave Star can be used as a base for offshore wind and photovoltaic installation in the middle of the sea, realizing an hybrid renewable energy platform. It is the authors´ believe that taking wave energy devices......-technical risks, it is critical to provide comprehensive and reliable information on the technologies without neglecting attractive advantages. It is possible to underline a different key of lecture of wave energy performance by considering efficiency and power production as well as device versatility...

  6. Nonlinear spatial mode imaging of hybrid photonic crystal fibers

    DEFF Research Database (Denmark)

    Petersen, Sidsel Rübner; Alkeskjold, Thomas Tanggaard; Laurila, Marko;

    2013-01-01

    Degenerate spontaneous four wave mixing is studied for the rst time in a large mode area hybrid photonic crystal ber, where light con nement is achieved by combined index- and bandgap guiding. Four wave mixing products are generated on the edges of the bandgaps, which is veri ed by numerical...

  7. Propagation of Electromagnetic Waves in Extremely Dense Media

    CERN Document Server

    Masood, Samina

    2016-01-01

    We study the propagation of electromagnetic (EM) waves in extremely dense exotic systems with very unique properties. These EM waves develop a longitudinal component due to its interaction with the medium. Renormalization scheme of QED is used to understand the propagation of EM waves in both longitudinal and transverse directions. The propagation of EM waves in a quantum statistically treatable medium affects the properties of the medium itself. The electric permittivity and the magnetic permeability of the medium are modified and influence the related behavior of the medium. All the electromagnetic properties of a medium become a function of temperature and chemical potential of the medium. We study in detail the modifications of electric permittivity and magnetic permeability and other related properties of a medium in the superdense stellar objects.

  8. Intuitionistic hybrid logic

    DEFF Research Database (Denmark)

    Braüner, Torben

    2011-01-01

    Intuitionistic hybrid logic is hybrid modal logic over an intuitionistic logic basis instead of a classical logical basis. In this short paper we introduce intuitionistic hybrid logic and we give a survey of work in the area.......Intuitionistic hybrid logic is hybrid modal logic over an intuitionistic logic basis instead of a classical logical basis. In this short paper we introduce intuitionistic hybrid logic and we give a survey of work in the area....

  9. Continuity Controlled Hybrid Automata

    OpenAIRE

    Bergstra, J. A.; Middelburg, C.A.

    2004-01-01

    We investigate the connections between the process algebra for hybrid systems of Bergstra and Middelburg and the formalism of hybrid automata of Henzinger et al. We give interpretations of hybrid automata in the process algebra for hybrid systems and compare them with the standard interpretation of hybrid automata as timed transition systems. We also relate the synchronized product operator on hybrid automata to the parallel composition operator of the process algebra. It turns out that the f...

  10. Crescimento e estado nutricional de abóbora híbrida em função de adubação orgânica e mineral Nutritional state of hybrid squash as a function of organic compost and mineral fertilizer

    Directory of Open Access Journals (Sweden)

    Natan F. Silva

    1999-11-01

    Full Text Available Foi conduzido um ensaio em estufa com cobertura plástica, em Viçosa, MG, com finalidade de avaliar a resposta da abóbora híbrida, cv. Tetsukabuto, a cinco doses (0, 25, 50, 100 e 150 g.dm-3 de composto orgânico produzido com resíduos de suínos e bagaço de cana em três níveis (0, 1 e 2 de adubação mineral (AM. No nível 1 da adubação mineral foram adicionados, em mg.dm-3 de substrato, os elementos: 150 de P; 50 de N; 75 de K; 20 de S; 58,5 de Ca; 14 de Mg; 0,5 de B; 0,5 de Cu; 1 de Zn e 0,1 de Mo. No nível 2 adicionou-se o dobro das doses dos nutrientes aplicadas no nível 1. O experimento foi em fatorial 5 x 3, e os tratamentos distribuídos em blocos ao acaso com quatro repetições. Cada parcela foi constituída por um vaso contendo 10 dm³ de substrato, com uma planta cada. Após 36 dias da semeadura, o composto orgânico e o adubo mineral propiciaram aumentos da área foliar, da matéria seca da parte aérea das plantas e aumentos dos teores de P, K e S e redução dos teores de N, Mg, e Ca na matéria seca do limbo foliar.An experiment was carried out in a plastic greenhouse, in Viçosa, Minas Gerais, Brazil, to evaluate the response of hybrid squash cv. Tetsukabuto to five rates (0, 25, 50, 100, and 150 g/dm³ of organic compost combined with three levels (0, 1 and 2 of mineral fertilizer. At level 1 of mineral fertilizer the following nutrients were added in mg per dm³ of substrate: 150 of P; 50 of N; 75 of K; 20 of S; 58.5 of Ca; 14 of Mg; 0.5 of B; 0.5 of Cu; 1 of Zn and 0.1 of Mo. At level 2, a double of the quantities applied at level 1 were added. The experiment was laid out as a 5 x 3 factorial arrangement, and the treatments randomly distributed in blocks, with four repetitions. Each sample comprised a pot containing 10 dm³ of substrate and a single plant. Thirty six days after planting the organic compost and mineral fertilizer resulted in increases in leaf area, dry weight of aerial parts, and P, K and S content

  11. Fusion of protoplasts with irradiated micro protoplasts as a tool for radiation hybrid panel in citrus;Fusao de protoplastos com microprotoplastos irradiados como ferramenta para painel hibrido de radiacao em citros

    Energy Technology Data Exchange (ETDEWEB)

    Bona, Claudine Maria de, E-mail: debona@iapar.b [Instituto Agronomico do Parana (IAPAR), Curitiba, PR (Brazil). Centro Administrativo do Governo do Estado; Stelly, David, E-mail: stelly@tamu.ed [Texas A and M University (Tamu), College Station, TX (United States). Dept. of Soil and Crop Sciences; Miller Junior, J. Creighton, E-mail: jcmillerjr@tamu.ed [Texas A and M University (Tamu), College Station, TX (United States). Dept. of Horticultural Sciences; Louzada, Eliezer Silva, E-mail: elouzada@ag.tamu.ed [Texas A and M University, (Tamuk), Weslaco, TX (United States)

    2009-12-15

    The objective of this work was to combine asymmetric somatic hybridization (donor-recipient fusion or gamma fusion) to microprotoplast-mediated chromosome transfer, as a tool to be used for chromosome mapping in Citrus. Swinglea glutinosa micro protoplasts were irradiated either with 50, 70, 100 or 200 gamma rays and fused to cv. Ruby Red grapefruit or Murcott tangor protoplasts. Cell colonies were successfully formed and AFLP analyses confirmed presence of S. glutinosa in both 'Murcott' tangor and 'Ruby Red' grapefruit genomes. (author)

  12. Produção de membranas híbridas zirconizadas de SPEEK/Copolissilsesquioxano para aplicação em células a combustível do tipo PEM Production of Zirconized SPEEK/Copolysilsesquioxane hybrid membranes for application in Proton Exchange Membrane fuel cells

    Directory of Open Access Journals (Sweden)

    Kelen R. Aguiar

    2012-01-01

    Full Text Available Membranas baseadas em poli(aril éter cetona sulfonada mostraram ser bastante promissoras para aplicação em células a combustível com membrana trocadora de prótons (PEMFC. O poli(éter-éter-cetona sulfonado (SPEEK, com elevado grau de sulfonação (GS, apresenta alta condutividade de prótons, mas sofre perda de funcionalidade e condutividade em temperaturas altas e umidades baixas. O desenvolvimento de membranas híbridas é uma das possibilidades para melhorar o desempenho destes materiais. Neste trabalho foram preparadas membranas híbridas zirconizadas de SPEEK/copolissilsesquioxano fosfonado (CF por casting, a partir de SPEEK com GS entre 60% e 70% e soluções de cloreto de zirconila (ZrOCl2 1, 5, ou 10% (m/m. As membranas foram caracterizadas por espectroscopia na região do infravermelho (FTIR, difratometria de raios-X (DRX, análise termogravimétrica (TG, calorimetria exploratória diferencial (DSC, condutividade de prótons (σ e microscopia eletrônica de varredura (MEV. A análise por energia dispersiva (EDS confirmou a presença de Zr em domínios esféricos dispersos homogeneamente pelas membranas, enquanto análises de DRX mostraram que os produtos da zirconização são amorfos. Ensaios de impedância eletroquímica indicam aumento da condutividade protônica com a adição de CF e 1 ou 5% de ZrOCl2.Membranes based on sulfonated poly(aryl ether ketone are known to be very promising materials for Proton Exchange Membrane Fuel Cells (PEMFC. Sulfonated poly(ether-ether-ketone (SPEEK, with high sulfonation degrees (SD, present high proton conductivity. However, they lose functionality and conductivity at high temperatures and low humidity. To enhance the performance of these materials, hybrid membranes have gained considerable attention. In this work, zirconized SPEEK/phosphonated copolysilsesquioxane (CF hybrid membranes were prepared by casting, from SPEEK (60% < SD < 70% and 1, 5, or 10 wt. (% zirconyl chloride solutions

  13. <em>α>-Glucosidase Inhibitory Constituents from <em>Acanthopanax senticosusem> Harm Leaves

    Directory of Open Access Journals (Sweden)

    Hai-Xue Kuang

    2012-05-01

    Full Text Available A new triterpene glycoside, 3-<em>O-[(α>-L-rhamnopyranosyl(1→2]-[<em>β>-D-glucuronopyranosyl-6-<em>O>-methyl ester]-olean-12-ene-28-olic acid (1 and a new indole alkaloid, 5-methoxy-2-oxoindolin-3-acetic acid methyl ester (5 were isolated from the leaves of <em>Acanthopanax senticosusem> Harms along with six known compounds. The structures of the new compounds were determined by means of 2D-NMR experiments and chemical methods. All the isolated compounds were evaluated for their glycosidase inhibition activities and compound 6 showed significant <em>α>-glucosidase inhibition activity.

  14. Making waves

    Science.gov (United States)

    Kruse, Karsten

    2017-01-01

    Traveling waves propagating along surfaces play an important role for intracellular organization. Such waves can appear spontaneously in reaction-diffusion systems, but only few general criteria for their existence are known. Analyzing the dynamics of the Min proteins in Escherichia coli, Levine and Kessler (2016 New J. Phys. 18 122001) now identified a new mechanism for the emergence of traveling waves that relies on conservation laws. From their analysis one can expect traveling waves to be a generic feature of systems made of proteins that have a cytoplasmic and a membrane-bound state.

  15. Janus Waves

    OpenAIRE

    2016-01-01

    We show the existence of a family of waves that share a common interesting property affecting the way they propagate and focus. These waves are a superposition of twin waves, which are conjugate to each other under inversion of the propagation direction. In analogy to holography, these twin "real" and "virtual" waves are related respectively to the converging and the diverging part of the beam and can be clearly visualized in real space at two distinct foci under the action of a focusing lens...

  16. Hybrid Verification by Exploiting the Environment

    Science.gov (United States)

    1994-07-01

    Lecture Notes in Computer Science Vol. 600, Springer-Verlag, 1992. [2] R. Alur, C. Courcoubetis, T.A. Henzinger, and...and H. Rischel, editors, Hybrid Systems, pages 209-229. Lecture Notes in Computer Science Vol. 736, Springer-Verlag, 1993. [3] H. Barringer, R. Kuiper...pages 36-59. Lecture Notes in Computer Science Vol. 736, Springer-Verlag, 1993. [6] E.M. Clarke, D.E. Long, and K.L. McMillan. Compositional

  17. Studies and mechanical properties of a new type of 'hybrid' ceramic block for buildings in structural masonry; Estudos e propriedades mecanicas de um novo tipo de bloco ceramico 'hibrido' para edificacoes em alvenarias estruturais

    Energy Technology Data Exchange (ETDEWEB)

    Camara, Cassio Freire; Gomes, Uilame Umbelino, E-mail: cfcamara@infra.ufrn.br, E-mail: umbelino@dfte.ufrn.br [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil). Programa de Pos-Graduacao em Ciencias e Engenharia de Materiais

    2012-07-01

    This paper presents the development of a hybrid ceramic block to the use of resides in the buildings executed with structural masonry. This work seeking new materials and / or products with the purpose of increasing the compressive strength of the ceramic blocks, without neglecting other properties (water absorption and linear shrinkage). After the obtained material (clay powder and crushed), the packaging (in percentages ranging from 0%, 5%, 10% and 15% substitution of crushed clay powder), the identification and measuring (weights and lengths) of the bodies of the test piece, was performed on the approach characterized by fluorescence, mineralogy and SEM of these materials as well as the characterization (SEM) of ceramic blocks after the sintering (temperature of the 900 deg C, 1000 deg C, and 1100 deg C rate with heating tax of 5{sup o}C/minute and soak for 1 hour). Then the samples were subjected to the tests (compressive strength and water absorption) and the respective calculated linear shrinkage. After conducting the analysis of the results of these tests (according to the criteria and parameters required by the ABNT NBR 15270) was found that the 'hybrid' block with the addition of 10% crushed powder obtained the best results, increasing the compressive strength at 16 % without compromising the other parameters required by the Standard. (author)

  18. Multiresolution wavelet-ANN model for significant wave height forecasting.

    Digital Repository Service at National Institute of Oceanography (India)

    Deka, P.C.; Mandal, S.; Prahlada, R.

    Hybrid wavelet artificial neural network (WLNN) has been applied in the present study to forecast significant wave heights (Hs). Here Discrete Wavelet Transformation is used to preprocess the time series data (Hs) prior to Artificial Neural Network...

  19. Statistical characterization of wave propagation in mine environments

    KAUST Repository

    Bakir, Onur

    2012-07-01

    A computational framework for statistically characterizing electromagnetic (EM) wave propagation through mine tunnels and galleries is presented. The framework combines a multi-element probabilistic collocation (ME-PC) method with a novel domain-decomposition (DD) integral equation-based EM simulator to obtain statistics of electric fields due to wireless transmitters in realistic mine environments. © 2012 IEEE.

  20. Hybridized tetraquarks

    Directory of Open Access Journals (Sweden)

    A. Esposito

    2016-07-01

    Full Text Available We propose a new interpretation of the neutral and charged X,Z exotic hadron resonances. Hybridized-tetraquarks are neither purely compact tetraquark states nor bound or loosely bound molecules but rather a manifestation of the interplay between the two. While meson molecules need a negative or zero binding energy, its counterpart for h-tetraquarks is required to be positive. The formation mechanism of this new class of hadrons is inspired by that of Feshbach metastable states in atomic physics. The recent claim of an exotic resonance in the Bs0π± channel by the D0 Collaboration and the negative result presented subsequently by the LHCb Collaboration are understood in this scheme, together with a considerable portion of available data on X,Z particles. Considerations on a state with the same quantum numbers as the X(5568 are also made.

  1. Hybridized Tetraquarks

    CERN Document Server

    Esposito, A.; Polosa, A.D.

    2016-01-01

    We propose a new interpretation of the neutral and charged X, Z exotic hadron resonances. Hybridized-tetraquarks are neither purely compact tetraquark states nor bound or loosely bound molecules. The latter would require a negative or zero binding energy whose counterpart in h-tetraquarks is a positive quantity. The formation mechanism of this new class of hadrons is inspired by that of Feshbach metastable states in atomic physics. The recent claim of an exotic resonance in the Bs pi+- channel by the D0 collaboration and the negative result presented subsequently by the LHCb collaboration are understood in this scheme, together with a considerable portion of available data on X, Z particles. Considerations on a state with the same quantum numbers as the X(5568) are also made.

  2. Two Photon Couplings of Hybrid Mesons

    CERN Document Server

    Page, P R

    1996-01-01

    A new formalism is developed for the two photon production of hybrid mesons via intermediate hadronic decays. In an adiabatic and non--relativistic context with spin 1 pair creation we obtain the first absolute estimates of unmixed hybrid production strengths to be small (0.03 - 3 eV) in relation to experimental meson widths (0.1 - 5 keV). Within this context, two photon collisions therefore strongly discriminate between hybrid and conventional meson wave function components at BaBar, Cleo II, LEP2 and LHC, filtering out non--gluonic components. Decay widths of unmixed hybrids are tiny. The formalism also induces conventional meson two photon widths roughly in agreement with experiment.

  3. Atom-Light Hybrid Interferometer.

    Science.gov (United States)

    Chen, Bing; Qiu, Cheng; Chen, Shuying; Guo, Jinxian; Chen, L Q; Ou, Z Y; Zhang, Weiping

    2015-07-24

    A new type of hybrid atom-light interferometer is demonstrated with atomic Raman amplification processes replacing the beam splitting elements in a traditional interferometer. This nonconventional interferometer involves correlated optical and atomic waves in the two arms. The correlation between atoms and light developed with the Raman process makes this interferometer different from conventional interferometers with linear beam splitters. It is observed that the high-contrast interference fringes are sensitive to the optical phase via a path change as well as the atomic phase via a magnetic field change. This new atom-light correlated hybrid interferometer is a sensitive probe of the atomic internal state and should find wide applications in precision measurement and quantum control with atoms and photons.

  4. Effect of wave localization on plasma instabilities

    Energy Technology Data Exchange (ETDEWEB)

    Levedahl, W.K.

    1987-01-01

    The Anderson model of wave localization in random media is invoked to study the effect of solar-wind density turbulence on plasma processes associated with the solar type-III radio burst. ISEE-3 satellite data indicate that a possible model for the type-III process is the parametric decay of Langmuir waves excited by solar-flare electron streams into daughter electromagnetic and ion-acoustic waves. The threshold for this instability, however, is much higher than observed Langmuir-wave levels because of rapid wave convection of the transverse electromagnetic daughter wave in the case where the solar wind is assumed homogeneous. Langmuir and transverse waves near critical density satisfy the Ioffe-Riegel criteria for wave localization in the solar wind with observed density fluctuations {approximately}1%. Computer simulations using a linearized hybrid code show that an electron beam will excite localized Langmuir waves in a plasma with density turbulence. An action-principle approach is used to develop a theory of nonlinear wave processes when waves are localized. A theory of resonant particles diffusion by localized waves is developed to explain the saturation of the beam-plasma instability.

  5. Optically induced interaction of magnetic moments in hybrid metamaterials.

    Science.gov (United States)

    Miroshnichenko, Andrey E; Luk'yanchuk, Boris; Maier, Stefan A; Kivshar, Yuri S

    2012-01-24

    We propose a novel type of hybrid metal-dielectric structures composed of silicon nanoparticles and split-ring resonators for advanced control of optically induced magnetic response. We reveal that a hybrid "metamolecule" may exhibit a strong distance-dependent magnetic interaction that may flip the magnetization orientation and support "antiferromagnetic" ordering in a hybrid metamaterial created by a periodic lattice of such metamolecules. The propagation of magnetization waves in the hybrid structures opens new ways for manipulating artificial "antiferromagnetic" ordering at high frequencies. © 2011 American Chemical Society

  6. Speed of Gravitational Waves from Strongly Lensed Gravitational Waves and Electromagnetic Signals

    Science.gov (United States)

    Fan, Xi-Long; Liao, Kai; Biesiada, Marek; Piórkowska-Kurpas, Aleksandra; Zhu, Zong-Hong

    2017-03-01

    We propose a new model-independent measurement strategy for the propagation speed of gravitational waves (GWs) based on strongly lensed GWs and their electromagnetic (EM) counterparts. This can be done in two ways: by comparing arrival times of GWs and their EM counterparts and by comparing the time delays between images seen in GWs and their EM counterparts. The lensed GW-EM event is perhaps the best way to identify an EM counterpart. Conceptually, this method does not rely on any specific theory of massive gravitons or modified gravity. Its differential setting (i.e., measuring the difference between time delays in GW and EM domains) makes it robust against lens modeling details (photons and GWs travel in the same lensing potential) and against internal time delays between GW and EM emission acts. It requires, however, that the theory of gravity is metric and predicts gravitational lensing similar to general relativity. We expect that such a test will become possible in the era of third-generation gravitational-wave detectors, when about 10 lensed GW events would be observed each year. The power of this method is mainly limited by the timing accuracy of the EM counterpart, which for kilonovae is around 1 04 s . This uncertainty can be suppressed by a factor of ˜1 010, if strongly lensed transients of much shorter duration associated with the GW event can be identified. Candidates for such short transients include short γ -ray bursts and fast radio bursts.

  7. Wave Dragon

    DEFF Research Database (Denmark)

    Tedd, James; Kofoed, Jens Peter; Friis-Madsen, Erik

    2008-01-01

    Since March 2003 a prototype of Wave Dragon has been tested in an inland sea in Denmark. This has been a great success with all subsystems tested and improved through working in an offshore environment. The project has proved the Wave Dragon device and has enabled the next stage, a production sized...

  8. Wave Dragon

    DEFF Research Database (Denmark)

    Tedd, James; Kofoed, Jens Peter; Friis-Madsen, Erik;

    2008-01-01

    Since March 2003 a prototype of Wave Dragon has been tested in an inland sea in Denmark. This has been a great success with all subsystems tested and improved through working in an offshore environment. The project has proved the Wave Dragon device and has enabled the next stage, a production sized...

  9. Wave Star

    DEFF Research Database (Denmark)

    Kramer, Morten; Brorsen, Michael; Frigaard, Peter

    Nærværende rapport beskriver numeriske beregninger af den hydrodynamiske interaktion mellem 5 flydere i bølgeenergianlægget Wave Star.......Nærværende rapport beskriver numeriske beregninger af den hydrodynamiske interaktion mellem 5 flydere i bølgeenergianlægget Wave Star....

  10. Wave Solutions

    CERN Document Server

    Christov, Ivan C

    2012-01-01

    In classical continuum physics, a wave is a mechanical disturbance. Whether the disturbance is stationary or traveling and whether it is caused by the motion of atoms and molecules or the vibration of a lattice structure, a wave can be understood as a specific type of solution of an appropriate mathematical equation modeling the underlying physics. Typical models consist of partial differential equations that exhibit certain general properties, e.g., hyperbolicity. This, in turn, leads to the possibility of wave solutions. Various analytical techniques (integral transforms, complex variables, reduction to ordinary differential equations, etc.) are available to find wave solutions of linear partial differential equations. Furthermore, linear hyperbolic equations with higher-order derivatives provide the mathematical underpinning of the phenomenon of dispersion, i.e., the dependence of a wave's phase speed on its wavenumber. For systems of nonlinear first-order hyperbolic equations, there also exists a general ...

  11. Dinâmica floral e abortamento de flores em híbridos de canola e mostarda castanha Floral dynamics and flower abortion in hybrids of canola and Indian mustard

    Directory of Open Access Journals (Sweden)

    Rafael Battisti

    2013-02-01

    Full Text Available O objetivo deste trabalho foi avaliar a dinâmica floral e determinar o índice de abortamento de flores de híbridos de canola (Brassica napus e de mostarda castanha (Brassica juncea, bem como determinar suas relações com as condições meteorológicas do Sul do Brasil. Durante a floração, dez híbridos de canola e dois de mostarda foram avaliados a cada três dias quanto ao número de flores abertas, de síliquas e de flores abortadas. O número acumulado e relativo de flores foi usado para avaliação da dinâmica floral. A relação desses números com a soma térmica acumulada durante a floração foi determinada por meio de modelo logístico. A partir dos coeficientes desse modelo, identificaram-se grupos de genótipos com diferentes taxas de emissão de flores. O abortamento de flores entre híbridos variou de 10,53 a 45,96% e correlacionou-se com a temperatura e a demanda evaporativa da atmosfera. Genótipos com maiores tempos térmicos entre o período de máxima emissão de flores e o final da floração geralmente apresentam maiores percentagens de abortamento de flores. O ajuste dos dados de emissão de flores aos de soma térmica do período da floração, por meio de modelo logístico, permite simular a dinâmica floral de híbridos de canola e mostarda castanha.The objective of this work was to evaluate the floral dynamics and to determine the index of flower abortion in canola (Brassica napus and Indian mustard (Brassica juncea hybrids, as well as to determine their relation with meteorological conditions of southern Brazil. During flowering, ten hybrids of canola and two of Indian mustard were evaluated every three days as to the number of open flowers, pods, and aborted flowers. The cumulative and the relative number of flowers were used to evaluate floral dynamics. The relation of these numbers with the accumulated thermal sum during flowering was determined with a logistic model. Groups of genotypes with different

  12. Strong Decays of Hybrid Mesons from the Heavy Quark Expansion of QCD

    CERN Document Server

    Page, P R

    1998-01-01

    We calculate the strong decays of hybrid mesons to conventional mesons for all the lowest lying J^PC hybrids of flavour uu, dd, ss, cc and bb. A decay operator developed from the heavy quark expansion of quantum chromodynamics is employed. We show that the selection rule that hybrid mesons do not decay to identical S-wave mesons, found in other models, is preserved. We predict decays of charmonium hybrids, discuss decays of J^PC=1^-+ exotic isovector hybrids of various masses, and interpret the \\pi(1800) as a hybrid meson.

  13. Estimativas de herdabilidade e correlações quanto à produção de grãos e outras características agronômicas em populações de trigo Variance, heritability and correlations in wheat hybrid populations for grain yield and other agronomic characteristics

    Directory of Open Access Journals (Sweden)

    CARLOS EDUARDO DE OLIVEIRA CAMARGO

    2000-02-01

    Full Text Available Objetivou-se estimar os valores da variância, da heterose e heterobeltiose, e da herdabilidade em sentido restrito quanto a altura da planta de trigo (Triticum aestivum L., comprimento da espiga, comprimento do internódio da raque e produção de grãos, e quanto às correlações de ambiente, fenotípicas e genéticas, entre essas características. Foram também estimados os graus de dominância em relação a todas as características, com exceção da produção de grãos. O experimento foi instalado em telado, no Núcleo Experimental de Campinas, empregando cruzamentos entre a cultivar IAC-227 (P1, de porte alto, e quatro linhagens mexicanas, de porte baixo: CMH 78.390/ CMH 77A. 917// CMH 79.215 (P2, CMH 79.959/2* CNO 79 (P3, CMH 79.481/ CMH 77A. 917 (P4 e CMH 80A. 747 (P5. Os valores da herdabilidade em sentido restrito, referente a altura da planta (0,608-0,861, comprimento da espiga (0,406-0,667, comprimento do internódio da raque (0,545-0,781 e produção de grãos (0,421-0,550 indicaram que grande parte da variabilidade genética verificada nas populações híbridas quanto a essas características foi causada por genes com ação aditiva. As correlações fenotípicas entre altura da planta e produção de grãos e entre comprimento da espiga e comprimento do internódio da raque foram positivas e significativas em todos os cruzamentos considerados, o que mostra haver associação entre esses caracteres; portanto, os resultados obtidos sugerem que o estudo de grandes populações F2 seria de interesse para assegurar maior freqüência de recombinantes desejáveis, originando plantas semi-anãs com elevado potencial produtivo.The objective of the present work was to estimate the variance, heterosis and heterobeltiosis, and the narrow-sense heritability values for grain yield , spike length, rachis internode length and height of wheat plants (Triticum aestivum L., as well as the environmental, phenotypic and genetic correlations

  14. Tenacidade à fratura translaminar dinâmica de um laminado híbrido metal-fibra para uso em elevadas temperaturas Translaminar dynamic fracture toughness of a hybrid fiber-metal laminate devised to high-temperature applications

    Directory of Open Access Journals (Sweden)

    José R. Tarpani

    2010-01-01

    Full Text Available A tenacidade à fratura translaminar dinâmica do laminado híbrido metal-fibra titânio-grafite com matriz termoplástica foi determinada sob as velocidades de impacto de 2,25 e 5,52 m/s, no intervalo de temperaturas de -196 a +180 °C, e comparada à de laminados compósitos convencionais de fibras de carbono e resina epóxi. Constatou-se que o laminado híbrido exibe uma tenacidade à iniciação da fratura inferior à dos compósitos tradicionais com fibras na forma de fita unidirecional, porém superior à dos laminados convencionais com fibras na forma de tecido bidirecional. Os ensaios de impacto revelaram que, comparativamente ao desempenho mecânico dos laminados carbono-epóxi, o emprego do laminado híbrido metal-fibra se justifica mais pela sua resistência à propagação do que à iniciação da fratura dinâmica.The translaminar dynamic fracture toughness of titanium-graphite hybrid fiber-metal laminate with thermoplastic matrix has been determined at the impact velocities of 2.25 and 5.52 m/s, within the temperature range from -196 to +180 ºC, and compared to that of conventional carbon-epoxy composite laminates. The hybrid laminate exhibits lower initiation fracture toughness than traditional unidirectional tape composites though it is tougher than conventional woven fabric laminates. Impact tests revealed that, if compared to the mechanical performance of conventional carbon-epoxy laminates, the fiber-metal laminate application must rely on its resistance to dynamic fracture propagation rather than on fracture initiation.

  15. Electromagnetic waves and electron anisotropies downstream of supercritical interplanetary shocks

    CERN Document Server

    Wilson, L B; Szabo, A; Breneman, A; Cattell, C A; Goetz, K; Kellogg, P J; Kersten, K; Kasper, J C; Maruca, B A; Pulupa, M

    2012-01-01

    We present waveform observations of electromagnetic lower hybrid and whistler waves with f_ci 1.01. Thus, the whistler mode waves appear to be driven by a heat flux instability and cause perpendicular heating of the halo electrons. The lower hybrid waves show a much weaker correlation between \\partialB and normalized heat flux magnitude and are often observed near magnetic field gradients. A third type of event shows fluctuations consistent with a mixture of both lower hybrid and whistler mode waves. These results suggest that whistler waves may indeed be regulating the electron heat flux and the halo temperature anisotropy, which is important for theories and simulations of electron distribution evolution from the sun to the earth.

  16. Continuity Controlled Hybrid Automata

    NARCIS (Netherlands)

    Bergstra, J.A.; Middelburg, C.A.

    2004-01-01

    We investigate the connections between the process algebra for hybrid systems of Bergstra and Middelburg and the formalism of hybrid automata of Henzinger et al. We give interpretations of hybrid automata in the process algebra for hybrid systems and compare them with the standard interpretation of

  17. Continuity controlled Hybrid Automata

    NARCIS (Netherlands)

    Bergstra, J.A.; Middelburg, C.A.

    2008-01-01

    We investigate the connections between the process algebra for hybrid systems of Bergstra and Middelburg and the formalism of hybrid automata of Henzinger et al. We give interpretations of hybrid automata in the process algebra for hybrid systems and compare them with the standard interpretation of

  18. Dynamic square superlattice of Faraday waves

    Science.gov (United States)

    Kahouadji, Lyes; Chergui, Jalel; Juric, Damir; Shin, Seungwon; Tuckerman, Laurette

    2014-11-01

    Faraday waves are computed in a 3D container using BLUE, a code based on a hybrid Front-Tracking/Level-set algorithm for Lagrangian tracking of arbitrarily deformable phase interfaces. A new dynamic superlattice pattern is described which consists of a set of square waves arranged in a two-by-two array. The corners of this array are connected by a bridge whose position oscillates in time between the two diagonals.

  19. Three New Myrsinol Diterpenes from <em>Euphorbia proliferaem> and Their Neuroprotective Activities

    Directory of Open Access Journals (Sweden)

    Yuanqiang Guo

    2012-08-01

    Full Text Available Three new myrsinol diterpenes were isolated from the roots of<em> em>>Euphorbia proliferaem>. Their structures were elucidated as 2<em>α-O>-isobutyryl-3<em>β>,5<em>α>,7<em>β>,10,15<em>β-penta-O>-acetyl-14<em>α-O>-benzoyl-10,18-dihydromyrsinol (1, 2<em>α-O>-isobutyryl-3<em>β-O>-propion-yl-5<em>α>,7<em>β>,10,15<em>β-tetra-O>-acetyl-10,18-dihydromyrsinol (2, and 2<em>α>,14<em>α-di-O>-benzoyl-3<em>β>,5<em>α>,7<em>β>,10,15<em>β-penta-O>-acetyl-10,18-dihydromyrsinol (3 on the basis of spectroscopic data analyses (IR, ESI-MS, HR-ESI-MS, and 1D and 2D NMR. Their neuroprotective activities were evaluated and compounds 1 and 2 showed neuroprotective effects against MPP+-induced neuronal cell death in SH-SY5Y cells.

  20. Avaliação de cinco híbridos de milho (Zea mays, L. em diferentes estádios de maturação: 3. Composição químico-bromatológica Evaluation of five corn hybrids (Zea mays, L. at different maturity stages: 3. Chemical-bromatology composition

    Directory of Open Access Journals (Sweden)

    Lúcia Maria Zeoula

    2003-06-01

    Full Text Available O objetivo do presente estudo foi avaliar cinco híbridos de milho (Zea mays L. Pioneer: superprecoce P32R21, os precoces P30R07, P3041 e P30F33 e o semiprecoce P30F80, quanto à composição química, em diferentes estádios de maturação. O delineamento utilizado foi de blocos ao acaso, com cinco tratamentos e quatro repetições. A colheita das amostras dos híbridos de milho foi adotada estimando-se os cinco estádios de maturação da planta: 30, 34, 38, 42 e 46% de matéria seca (MS. Para cada estádio de maturação, procedeu-se à separação de colmo + bainha, lâmina foliar e do grão para posteriores analises químicas. Da fração grão, foram determinados os teores de nitrogênio total e de amido, nos cinco estádios de maturação. Nas frações de lâmina foliar e colmo + bainha, foram determinados os teores de fibra em detergente ácido (FDA, fibra em detergente neutro (FDN, lignina, nitrogênio insolúvel em detergente ácido (NIDA e nitrogênio total. Para os parâmetros avaliados observou-se diferença entre os híbridos de milho e efeito de dias pós-plantio. Com o avanço do estádio de maturação, observou-se que houve ligeira redução nos teores de proteína bruta (PB e os teores de amido praticamente não variaram no grão. Para a fração lâmina foliar, verificou-se que, com o aumento nos teores de matéria seca da planta, houve queda nos teores de PB e NIDA, ao contrário da fração colmo + bainha, cujos teores aumentaram. Os teores de FDN, FDA e lignina na lâmina foliar aumentaram, porém esses nutrientes na fração colmo + bainha dos híbridos de milho, praticamente, não variaram com o avanço do estádio de maturação.The objective of this study was evaluate, of the chemical composition of five corn (Zea mays L. hybrids Pioneer: P32R21, P30R07, P3041, P30F33 and P30F80, at different maturity stages. The treatments were used in plots of 7 x 8 m in a randomized block design, with four replicates. The samples

  1. Waves, damped wave and observation

    CERN Document Server

    Phung, Kim Dang

    2009-01-01

    We consider the wave equation in a bounded domain (eventually convex). Two kinds of inequality are described when occurs trapped ray. Applications to control theory are given. First, we link such kind of estimate with the damped wave equation and its decay rate. Next, we describe the design of an approximate control function by an iterative time reversal method.

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

    Science.gov (United States)

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

    2016-12-01

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

  3. Gravity waves

    Science.gov (United States)

    Fritts, David

    1987-02-01

    Gravity waves contributed to the establishment of the thermal structure, small scale (80 to 100 km) fluctuations in velocity (50 to 80 m/sec) and density (20 to 30%, 0 to peak). Dominant gravity wave spectrum in the middle atmosphere: x-scale, less than 100 km; z-scale, greater than 10 km; t-scale, less than 2 hr. Theorists are beginning to understand middle atmosphere motions. There are two classes: Planetary waves and equatorial motions, gravity waves and tidal motions. The former give rise to variability at large scales, which may alter apparent mean structure. Effects include density and velocity fluctuations, induced mean motions, and stratospheric warmings which lead to the breakup of the polar vortex and cooling of the mesosphere. On this scale are also equatorial quasi-biennial and semi-annual oscillations. Gravity wave and tidal motions produce large rms fluctuations in density and velocity. The magnitude of the density fluctuations compared to the mean density is of the order of the vertical wavelength, which grows with height. Relative density fluctuations are less than, or of the order of 30% below the mesopause. Such motions may cause significant and variable convection, and wind shear. There is a strong seasonal variation in gravity wave amplitude. Additional observations are needed to address and quantify mean and fluctuation statistics of both density and mean velocity, variability of the mean and fluctuations, and to identify dominant gravity wave scales and sources as well as causes of variability, both temporal and geographic.

  4. Computational and theoretical study of the wave-particle interaction of protons and waves

    Energy Technology Data Exchange (ETDEWEB)

    Moya, P.S.; Munoz, V. [Chile Univ., Santiago (Chile). Dept. de Fisica; Vinas, A.F. [NASA Goddard Space Flight Center, Greenbelt, MD (United States). Heliophysics Science Div.; Valdivia, J.A. [Chile Univ., Santiago (Chile). Dept. de Fisica; Centro para el Desarrollo de la Nanociencia y Nanotecnologia, CEDENNA (Chile); CEIBA complejidad, Bogota (Colombia)

    2012-11-01

    We study the wave-particle interaction and the evolution of electromagnetic waves propagating through a plasma composed of electrons and protons, using two approaches. First, a quasilinear kinetic theory has been developed to study the energy transfer between waves and particles, with the subsequent acceleration and heating of protons. Second, a one-dimensional hybrid numerical simulation has been performed, with and without including an expanding-box model that emulates the spherical expansion of the solar wind, to investigate the fully nonlinear evolution of this wave-particle interaction. Numerical results of both approaches show that there is an anisotropic evolution of proton temperature. (orig.)

  5. Effect of age of a sorghum-sudangrass hybrid on its allelopathic action Efeito da idade de um híbrido de sorgo com capim-sudão em sua ação alelopática

    Directory of Open Access Journals (Sweden)

    G. Marchi

    2008-01-01

    Full Text Available Hybrids of Sorghum sudanensis (sudangrass and Sorghum bicolor genotypes can produce high amounts of biomass, sorgoleone (a long chain hydroquinone, and other phytotoxic substances. Shoots and roots of a sorghum-sudangrass hybrid (cv. Trudan 8 were collected 10, 20, 30, 40, and 50 days after emergence. Four concentrations of aqueous extracts from the shoots and roots (0, 0.4, 2, and 10 g L-1, w/v were used to treat seeds of lettuce (Lactuca sativa, tomato (Lycopersicum sculentum, purslane (Portulaca oleracea, and pigweed (Amaranthus retroflexus. Seed germination of lettuce, tomato, and pigweed was inhibited by extracts from sorghum-sudangrass shoots at 10 g L-1 when made from sorghum-sudangrass plants 20 days or less in age. Seed germination of purslane was not inhibited by any sorghum-sudangrass extract. Growth of the four species evaluated were systematically inhibited when treated with 10 g L-1 extracts from sorghum-sudangrass shoots harvested up to 10 days after emergence.Os capins híbridos obtidos pelo cruzamento entre Sorghum sudanensis (capim-sudão e genótipos de Sorghum bicolor possuem alto potencial para produção de biomassa e para controle de plantas daninhas pela produção de substâncias fitotóxicas, como o sorgoleone (uma hidroquinona de cadeia longa. Sementes de alface (Lactuca sativa, tomate (Lycopersicum sculentum, beldroega (Portulaca oleracea e caruru (Amaranthus retroflexus foram submetidas a tratamentos com extratos aquosos da parte aérea e das raízes do híbrido de sorgo com capim-sudão, cv. Trudan 8, colhido em cinco diferentes estádios de crescimento (10, 20, 30, 40 e 50 dias após a emergência. Os extratos foram preparados em quatro concentrações (0, 0,4, 2 e 10 g L-1, p/v e aplicados em quatro repetições. Após os tratamentos, a germinação e o comprimento de plântulas das espécies foram avaliados. A germinação de sementes de tomate, caruru e alface foi inibida pelos extratos da parte aérea das

  6. PEMFC Optimization Strategy with Auxiliary Power Source in Fuel Cell Hybrid Vehicle

    Directory of Open Access Journals (Sweden)

    Tinton Dwi Atmaja

    2012-02-01

    Full Text Available Page HeaderOpen Journal SystemsJournal HelpUser You are logged in as...aulia My Journals My Profile Log Out Log Out as UserNotifications View (27 new ManageJournal Content SearchBrowse By Issue By Author By Title Other JournalsFont SizeMake font size smaller Make font size default Make font size largerInformation For Readers For Authors For LibrariansKeywords CBPNN Displacement FLC LQG/LTR Mixed PMA Ventilation bottom shear stress direct multiple shooting effective fuzzy logic geoelectrical method hourly irregular wave missile trajectory panoramic image predator-prey systems seawater intrusion segmentation structure development pattern terminal bunt manoeuvre Home About User Home Search Current Archives ##Editorial Board##Home > Vol 23, No 1 (2012 > AtmajaPEMFC Optimization Strategy with Auxiliary Power Source in Fuel Cell Hybrid VehicleTinton Dwi Atmaja, Amin AminAbstractone of the present-day implementation of fuel cell is acting as main power source in Fuel Cell Hybrid Vehicle (FCHV. This paper proposes some strategies to optimize the performance of Polymer Electrolyte Membrane Fuel Cell (PEMFC implanted with auxiliary power source to construct a proper FCHV hybridization. The strategies consist of the most updated optimization method determined from three point of view i.e. Energy Storage System (ESS, hybridization topology and control system analysis. The goal of these strategies is to achieve an optimum hybridization with long lifetime, low cost, high efficiency, and hydrogen consumption rate improvement. The energy storage system strategy considers battery, supercapacitor, and high-speed flywheel as the most promising alternative auxiliary power source. The hybridization topology strategy analyzes the using of multiple storage devices injected with electronic components to bear a higher fuel economy and cost saving. The control system strategy employs nonlinear control system to optimize the ripple factor of the voltage and the current

  7. Wave Dragon

    DEFF Research Database (Denmark)

    Tedd, James; Kofoed, Jens Peter; Knapp, W.

    2006-01-01

    Wave Dragon is a floating wave energy converter working by extracting energy principally by means of overtopping of waves into a reservoir. A 1:4.5 scale prototype has been sea tested for 20 months. This paper presents results from testing, experiences gained and developments made during...... this extended period. The prototype is highly instrumented. The overtopping characteristic and the power produced are presented here. This has enabled comparison between the prototype and earlier results from both laboratory model and computer simulation. This gives the optimal operating point and the expected...

  8. Transmission of electromagnetic waves through sub-wavelength channels

    DEFF Research Database (Denmark)

    Zhang, Jingjing; Luo, Yu; Mortensen, Asger

    2010-01-01

    We propose a method of tunneling electromagnetic (EM) waves through a channel with sub-wavelength cross section. By filling the channel with high-ε isotropic material and implementing two matching layers with uniaxial metamterial substrates, the guided waves can go through the narrow channel...

  9. The effects of age on visual perception of sine-wave gratings at low luminance / Os efeitos da idade na percepção visual de grades senoidais em luminância baixa

    Directory of Open Access Journals (Sweden)

    Natanael Antonio dos Santos

    2006-01-01

    Full Text Available The aim of this work was to investigate the contrast sensitivity function for sine-wave gratings in the range between 0.25-2 cpd in young and older adults (20-23, 30-39, 40-49, 50-59, 60-69 years old using low luminance. All subjects were free from identifiable ocular disease and had normal acuity. We measured the contrast thresholds for 30 participants (six volunteers in each age using the psychophysical forced-choice staircase method. In this method the volunteers had to choose the stimulus containing a test frequency at low contrast (e.g., a sine-wave grating, or another neutral stimulus at mean luminance (0.7 cd/m2. The results showed significant changes of CSF for sine-wave gratings at 1 and 2 cpd for the adults 50-59 and 60-69 years old compared to the adults of 20-23 years old. These results suggest age-related changes in the CSF for sine-wave grating at low luminance levels.

  10. Neonatal Phosphate Nutrition Alters <em>in em>Vivo> and <em>in em>Vitro> Satellite Cell Activity in Pigs

    Directory of Open Access Journals (Sweden)

    Chad H. Stahl

    2012-05-01

    Full Text Available Satellite cell activity is necessary for postnatal skeletal muscle growth. Severe phosphate (PO4 deficiency can alter satellite cell activity, however the role of neonatal PO4 nutrition on satellite cell biology remains obscure. Twenty-one piglets (1 day of age, 1.8 ± 0.2 kg BW were pair-fed liquid diets that were either PO4 adequate (0.9% total P, supra-adequate (1.2% total P in PO4 requirement or deficient (0.7% total P in PO4 content for 12 days. Body weight was recorded daily and blood samples collected every 6 days. At day 12, pigs were orally dosed with BrdU and 12 h later, satellite cells were isolated. Satellite cells were also cultured <em>in vitroem> for 7 days to determine if PO4 nutrition alters their ability to proceed through their myogenic lineage. Dietary PO4 deficiency resulted in reduced (<em>P> < 0.05 sera PO4 and parathyroid hormone (PTH concentrations, while supra-adequate dietary PO4 improved (<em>P> < 0.05 feed conversion efficiency as compared to the PO4 adequate group. <em>In vivoem> satellite cell proliferation was reduced (<em>P> < 0.05 among the PO4 deficient pigs, and these cells had altered <em>in vitroem> expression of markers of myogenic progression. Further work to better understand early nutritional programming of satellite cells and the potential benefits of emphasizing early PO4 nutrition for future lean growth potential is warranted.

  11. Ion cyclotron waves at Titan

    Science.gov (United States)

    Russell, C. T.; Wei, H. Y.; Cowee, M. M.; Neubauer, F. M.; Dougherty, M. K.

    2016-03-01

    During the interaction of Titan's thick atmosphere with the ambient plasma, it was expected that ion cyclotron waves would be generated by the free energy of the highly anisotropic velocity distribution of the freshly ionized atmospheric particles created in the interaction. However, ion cyclotron waves are rarely observed near Titan, due to the long growth times of waves associated with the major ion species from Titan's ionosphere, such as CH4+ and N2+. In the over 100 Titan flybys obtained by Cassini to date, there are only two wave events, for just a few minutes during T63 flyby and for tens of minutes during T98 flyby. These waves occur near the gyrofrequencies of proton and singly ionized molecular hydrogen. They are left-handed, elliptically polarized, and propagate nearly parallel to the field lines. Hybrid simulations are performed to understand the wave growth under various conditions in the Titan environment. The simulations using the plasma and field conditions during T63 show that pickup protons with densities ranging from 0.01 cm-3 to 0.02 cm-3 and singly ionized molecular hydrogens with densities ranging from 0.015 cm-3 to 0.25 cm-3 can drive ion cyclotron waves with amplitudes of ~0.02 nT and of ~0.04 nT within appropriate growth times at Titan, respectively. Since the T98 waves were seen farther upstream than the T63 waves, it is possible that the instability was stronger and grew faster on T98 than T63.

  12. Janus Waves

    CERN Document Server

    Papazoglou, Dimitris G; Tzortzakis, Stelios

    2016-01-01

    We show the existence of a family of waves that share a common interesting property affecting the way they propagate and focus. These waves are a superposition of twin waves, which are conjugate to each other under inversion of the propagation direction. In analogy to holography, these twin "real" and "virtual" waves are related respectively to the converging and the diverging part of the beam and can be clearly visualized in real space at two distinct foci under the action of a focusing lens. Analytic formulas for the intensity distribution after focusing are derived, while numerical and experimental demonstrations are given for some of the most interesting members of this family, the accelerating Airy and ring-Airy beams.

  13. Design guidelines of triboelectric nanogenerator for water wave energy harvesters

    Science.gov (United States)

    Ahmed, Abdelsalam; Hassan, Islam; Jiang, Tao; Youssef, Khalid; Liu, Lian; Hedaya, Mohammad; Abu Yazid, Taher; Zu, Jean; Wang, Zhong Lin

    2017-05-01

    Ocean waves are one of the cleanest and most abundant energy sources on earth, and wave energy has the potential for future power generation. Triboelectric nanogenerator (TENG) technology has recently been proposed as a promising technology to harvest wave energy. In this paper, a theoretical study is performed on a duck-shaped TENG wave harvester recently introduced in our work. To enhance the design of the duck-shaped TENG wave harvester, the mechanical and electrical characteristics of the harvester’s overall structure, as well as its inner configuration, are analyzed, respectively, under different wave conditions, to optimize parameters such as duck radius and mass. Furthermore, a comprehensive hybrid 3D model is introduced to quantify the performance of the TENG wave harvester. Finally, the influence of different TENG parameters is validated by comparing the performance of several existing TENG wave harvesters. This study can be applied as a guideline for enhancing the performance of TENG wave energy harvesters.

  14. Design guidelines of triboelectric nanogenerator for water wave energy harvesters

    KAUST Repository

    Ahmed, Abdelsalam

    2017-04-11

    Ocean waves are one of the cleanest and most abundant energy sources on earth, and wave energy has the potential for future power generation. Triboelectric nanogenerator (TENG) technology has recently been proposed as a promising technology to harvest wave energy. In this paper, a theoretical study is performed on a duck-shaped TENG wave harvester recently introduced in our work. To enhance the design of the duck-shaped TENG wave harvester, the mechanical and electrical characteristics of the harvester\\'s overall structure, as well as its inner configuration, are analyzed, respectively, under different wave conditions, to optimize parameters such as duck radius and mass. Furthermore, a comprehensive hybrid 3D model is introduced to quantify the performance of the TENG wave harvester. Finally, the influence of different TENG parameters is validated by comparing the performance of several existing TENG wave harvesters. This study can be applied as a guideline for enhancing the performance of TENG wave energy harvesters.

  15. Coordenação local do Eu(III em híbridos orgânicos/inorgânicos emissores de luz branca Eu(III local coordination in white light emitters organic-inorganic hybrids

    Directory of Open Access Journals (Sweden)

    Luís D. Carlos

    2001-08-01

    Full Text Available Eu3+ luminescence and EXAFS (Extended X-ray Absorption Fine Structure results are presented for organic-inorganic hybrid gel hosts composed of a siliceous network to which small chains of oxyethylene units are covalently grafted by means of urea bridges. Coordination numbers for Eu3+ ions range from 12.8 to 9.7 with increasing Eu3+ concentration while the Eu3+-first neighbours mean distance is found to be constant at 2.48-2.49 Å in the same concentration range. Emission spectra display a broad band in the green/blue spectral region superposed to narrow lines appearing in the yellow/red region in such a way that for the eyes emission appears white. The broad band is assigned to intrinsic NH groups emission and also to electron-hole recombination in the nanosised siliceous domains. The narrow lines are assigned to intra-4f6, 5D0->7F0-4 Eu3+ transitions and from the energy position of the 7F0-4 levels a mean distance could be calculated for the Eu3+-first neighbours. The calculated results are in good agreement with the experimental ones obtained from EXAFS analysis.

  16. Bottleneck Accumulation of Hybrid Magnetoelastic Bosons

    Science.gov (United States)

    Bozhko, Dmytro A.; Clausen, Peter; Melkov, Gennadii A.; L'vov, Victor S.; Pomyalov, Anna; Vasyuchka, Vitaliy I.; Chumak, Andrii V.; Hillebrands, Burkard; Serga, Alexander A.

    2017-06-01

    An ensemble of magnons, quanta of spin waves, can be prepared as a Bose gas of weakly interacting quasiparticles. Furthermore, the thermalization of the overpopulated magnon gas through magnon-magnon scattering processes, which conserve the number of particles, can lead to the formation of a Bose-Einstein condensate at the bottom of a spin-wave spectrum. However, magnon-phonon scattering can significantly modify this scenario and new quasiparticles are formed—magnetoelastic bosons. Our observations of a parametrically populated magnon gas in a single-crystal film of yttrium iron garnet by means of wave-vector-resolved Brillouin light scattering spectroscopy evidence a novel condensation phenomenon: A spontaneous accumulation of hybrid magnetoelastic bosonic quasiparticles at the intersection of the lowest magnon mode and a transversal acoustic wave.

  17. Wave Star

    DEFF Research Database (Denmark)

    Kramer, Morten; Frigaard, Peter

    Nærværende rapport beskriver modelforsøg udført på Aalborg Universitet, Institut for Byggeri og Anlæg med bølgeenergianlæget Wave Star.......Nærværende rapport beskriver modelforsøg udført på Aalborg Universitet, Institut for Byggeri og Anlæg med bølgeenergianlæget Wave Star....

  18. Wave Star

    DEFF Research Database (Denmark)

    Kramer, Morten; Andersen, Thomas Lykke

    Nærværende rapport beskriver modelforsøg udført på Aalborg Universitet, Institut for Vand, Jord og Miljøteknik med bølgeenergianlægget Wave Star.......Nærværende rapport beskriver modelforsøg udført på Aalborg Universitet, Institut for Vand, Jord og Miljøteknik med bølgeenergianlægget Wave Star....

  19. Cluster observations in the magnetosheath - Part 1: Anisotropies of the wave vector distribution of the turbulence at electron scales

    Science.gov (United States)

    Mangeney, A.; Lacombe, C.; Maksimovic, M.; Samsonov, A. A.; Cornilleau-Wehrlin, N.; Harvey, C. C.; Bosqued, J.-M.; Trávníček, P.

    2006-12-01

    We analyse the power spectral density δB2 and δE2 of the magnetic and electric fluctuations measured by Cluster 1 (Rumba) in the magnetosheath during 23 h, on four different days. The frequency range of the STAFF Spectral Analyser (f=8 Hz to 4 kHz) extends from about the lower hybrid frequency, i.e. the electromagnetic (e.m.) range, up to about 10 times the proton plasma frequency, i.e. the electrostatic (e.s.) range. In the e.m. range, we do not consider the whistler waves, which are not always observed, but rather the underlying, more permanent fluctuations. In this e.m. range, δB2 (at 10 Hz) increases strongly while the local angle ΘBV between the magnetic field B and the flow velocity V increases from 0° to 90°. This behaviour, also observed in the solar wind at lower frequencies, is due to the Doppler effect. It can be modelled if we assume that, for the scales ranging from kc/ωpe≃0.3 to 30 (c/ωpe is the electron inertial length), the intensity of the e.m. fluctuations for a wave number k (i) varies like k-ν with ν>≃3, (ii) peaks for wave vectors k perpendicular to B like |sinθkB|µ with µ>≃100. The shape of the observed variations of δB2 with f and with ΘBV implies that the permanent fluctuations, at these scales, statistically do not obey the dispersion relation for fast/whistler waves or for kinetic Alfvén waves: the fluctuations have a vanishing frequency in the plasma frame, i.e. their phase velocity is negligible with respect to V (Taylor hypothesis). The electrostatic waves around 1 kHz behave differently: δE2 is minimum for ΘBV>≃90°. This can be modelled, still with the Doppler effect, if we assume that, for the scales ranging from k λDe>≃0.1 to 1 (λDe is the Debye length), the intensity of the e.s. fluctuations (i) varies like k-ν with ν>≃4, (ii) peaks for k parallel to B like |cosθkB|µ with µ>≃100. These e.s. fluctuations may have a vanishing frequency in the plasma frame, or may be ion acoustic waves. Our

  20. Cluster observations in the magnetosheath – Part 1: Anisotropies of the wave vector distribution of the turbulence at electron scales

    Directory of Open Access Journals (Sweden)

    J.-M. Bosqued

    2006-12-01

    Full Text Available We analyse the power spectral density δB2 and δE2 of the magnetic and electric fluctuations measured by Cluster 1 (Rumba in the magnetosheath during 23 h, on four different days. The frequency range of the STAFF Spectral Analyser (f=8 Hz to 4 kHz extends from about the lower hybrid frequency, i.e. the electromagnetic (e.m. range, up to about 10 times the proton plasma frequency, i.e. the electrostatic (e.s. range. In the e.m. range, we do not consider the whistler waves, which are not always observed, but rather the underlying, more permanent fluctuations. In this e.m. range, δB2 (at 10 Hz increases strongly while the local angle ΘBV between the magnetic field B and the flow velocity V increases from 0° to 90°. This behaviour, also observed in the solar wind at lower frequencies, is due to the Doppler effect. It can be modelled if we assume that, for the scales ranging from kc/ωpe≃0.3 to 30 (c/ωpe is the electron inertial length, the intensity of the e.m. fluctuations for a wave number k (i varies like k−ν with ν>≃3, (ii peaks for wave vectors k perpendicular to B like |sinθkB|µ with µ>≃100. The shape of the observed variations of δB2 with f and with ΘBV implies that the permanent fluctuations, at these scales, statistically do not obey the dispersion relation for fast/whistler waves or for kinetic Alfvén waves: the fluctuations have a vanishing frequency in the plasma frame, i.e. their phase velocity is negligible with respect to V (Taylor hypothesis. The electrostatic waves around 1 kHz behave differently: δE2 is minimum for ΘBV>≃90°. This can be modelled, still with the Doppler effect, if we assume that, for the scales ranging from k λDe>≃0.1 to 1 (λDe is the Debye length, the intensity of the e.s. fluctuations (i varies like k−ν with ν>≃4, (ii peaks for k parallel to B like |cosθkB|µ with µ>≃100. These e.s. fluctuations may have a vanishing frequency in the plasma frame, or may be ion acoustic

  1. Human papillomavirus detection in cervical dysplasias or neoplasias and in condylomata acuminaata by in situ hybridization with biotinylated DNA probes Detecção de papilomavirus humano em displasias ou neoplasias cervicais e em condilomas acuminados por hibridização in situ com sondas de DNA biotiniladas

    OpenAIRE

    Eliane Machado Guimarães; Geraldo Brasileiro Filho; Sérgio Danilo Junho Pena

    1992-01-01

    Specimens from cervical dysplasias or carcinomas and genital condylomata acuminata were retrospectively analysed by in situ hybridization (ISH) with bioti-nylated DNA probes for human papillomavirus (HPV) types 6, 11, 16 and 18. In the control group no case was positive for HPV DNA. In mild/moderate dysplasias, 4 cases (14%) were positive for HPV 6 or 11 and 2 cases (7%), for HPV 16. In the severe dysplasia/in situ carcinoma group, 9 cases (31%) showed presence of DNA of HPV types 16 or 18. S...

  2. Image segmentation by EM-based adaptive pulse coupled neural networks in brain magnetic resonance imaging.

    Science.gov (United States)

    Fu, J C; Chen, C C; Chai, J W; Wong, S T C; Li, I C

    2010-06-01

    We propose an automatic hybrid image segmentation model that integrates the statistical expectation maximization (EM) model and the spatial pulse coupled neural network (PCNN) for brain magnetic resonance imaging (MRI) segmentation. In addition, an adaptive mechanism is developed to fine tune the PCNN parameters. The EM model serves two functions: evaluation of the PCNN image segmentation and adaptive adjustment of the PCNN parameters for optimal segmentation. To evaluate the performance of the adaptive EM-PCNN, we use it to segment MR brain image into gray matter (GM), white matter (WM) and cerebrospinal fluid (CSF). The performance of the adaptive EM-PCNN is compared with that of the non-adaptive EM-PCNN, EM, and Bias Corrected Fuzzy C-Means (BCFCM) algorithms. The result is four sets of boundaries for the GM and the brain parenchyma (GM+WM), the two regions of most interest in medical research and clinical applications. Each set of boundaries is compared with the golden standard to evaluate the segmentation performance. The adaptive EM-PCNN significantly outperforms the non-adaptive EM-PCNN, EM, and BCFCM algorithms in gray mater segmentation. In brain parenchyma segmentation, the adaptive EM-PCNN significantly outperforms the BCFCM only. However, the adaptive EM-PCNN is better than the non-adaptive EM-PCNN and EM on average. We conclude that of the three approaches, the adaptive EM-PCNN yields the best results for gray matter and brain parenchyma segmentation.

  3. Plug-in hybrid electric vehicles in dynamical energy markets

    NARCIS (Netherlands)

    Kessels, J.T.B.A.; Bosch, P.P.J. van den

    2008-01-01

    The plug-in hybrid electric vehicle allows vehicle propulsion from multiple internal power sources. Electric energy from the grid can be utilized by means of the plug-in connection. An on-line energy management (EM) strategy is proposed to minimize the costs for taking energy from each power source.

  4. Plug-in hybrid electric vehicles in dynamical energy markets

    NARCIS (Netherlands)

    Kessels, J.T.B.A.; Bosch, P.P.J. van den

    2008-01-01

    The plug-in hybrid electric vehicle allows vehicle propulsion from multiple internal power sources. Electric energy from the grid can be utilized by means of the plug-in connection. An on-line energy management (EM) strategy is proposed to minimize the costs for taking energy from each power source.

  5. Blast Waves

    CERN Document Server

    Needham, Charles E

    2010-01-01

    The primary purpose of this text is to document many of the lessons that have been learned during the author’s more than forty years in the field of blast and shock. The writing therefore takes on an historical perspective, in some sense, because it follows the author’s experience. The book deals with blast waves propagating in fluids or materials that can be treated as fluids. It begins by distinguishing between blast waves and the more general category of shock waves. It then examines several ways of generating blast waves, considering the propagation of blast waves in one, two and three dimensions as well as through the real atmosphere. One section treats the propagation of shocks in layered gases in a more detailed manner. The book also details the interaction of shock waves with structures in particular reflections, progressing from simple to complex geometries, including planar structures, two-dimensional structures such as ramps or wedges, reflections from heights of burst, and three-dimensional st...

  6. Constituents from <em>Vigna em>vexillata> and Their Anti-Inflammatory Activity

    Directory of Open Access Journals (Sweden)

    Guo-Feng Chen

    2012-08-01

    Full Text Available The seeds of <em>Vigna em>genus are important food resources and there have already been many reports regarding their bioactivities. In our preliminary bioassay, the chloroform layer of methanol extracts of<em> V. vexillata em>demonstrated significant anti-inflammatory bioactivity. Therefore, the present research is aimed to purify and identify the anti-inflammatory principles of <em>V. vexillataem>. One new sterol (1 and two new isoflavones (2,3 were reported from the natural sources for the first time and their chemical structures were determined by the spectroscopic and mass spectrometric analyses. In addition, 37 known compounds were identified by comparison of their physical and spectroscopic data with those reported in the literature. Among the isolates, daidzein (23, abscisic acid (25, and quercetin (40 displayed the most significant inhibition of superoxide anion generation and elastase release.

  7. Fuzzy Energy Management for a Catenary-Battery-Ultracapacitor based Hybrid Tramway

    Science.gov (United States)

    Jibin, Yang; Jiye, Zhang; Pengyun, Song

    2017-05-01

    In this paper, an energy management strategy (EMS) based on fuzzy logic control for a catenary-battery-ultracapacitor powered hybrid modern tramway was presented. The fuzzy logic controller for the catenary zone and catenary-less zone was respectively designed by analyzing the structure and working mode of the hybrid system, then an energy management strategy based on double fuzzy logic control was proposed to enhance the fuel economy. The hybrid modern tramway simulation model was developed based on MATLAB/Simulink environment. The simulation results show that the proposed EMS can satisfy the demand of dynamic performance of the tramway and achieve the power distribution reasonably between the each power source.