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Sample records for multiband nonthermal radiative

  1. MULTIBAND NONTHERMAL RADIATIVE PROPERTIES OF HESS J1813-178

    SciTech Connect

    Fang Jun; Zhang Li

    2010-07-20

    The source HESS J1813-178 was detected in a survey of the inner Galaxy in TeV {gamma}-rays, and a composite supernova remnant (SNR) G12.8-0.0 was identified in the radio band to be associated with it. The pulsar wind nebula (PWN) embedded in the SNR is powered by an energetic pulsar PSR J1813-1749, which was recently discovered. Whether the TeV {gamma}-rays originate from the SNR shell or the PWN is currently uncertain. We theoretically investigate the multiwavelength nonthermal radiation from the composite SNR G12.8-0.0. The emission from the particles accelerated in the SNR shell is calculated by applying a semianalytical method to the nonlinear diffusive shock acceleration mechanism. In the model, the magnetic field is self-generated via resonant streaming instability, and the dynamical reaction of the field on the shock is taken into account. Based on a model which couples the dynamical and radiative evolution of a PWN in a non-radiative SNR, the dynamics and the multiband emission of the PWN are investigated. The particles are injected with the spectrum of a relativistic Maxwellian plus a power-law high-energy tail with an index of -2.5. Our results indicate that the radio emission from the shell can be reproduced well as synchrotron radiation of the electrons accelerated by the SNR shock; with an interstellar medium number density of 1.4 cm{sup -3} for the remnant, the {gamma}-ray emission from the SNR shell is insignificant and the observed X-rays and very high energy (VHE) {gamma}-rays from the source are consistent with the emission produced by electrons/positrons injected in the PWN via synchrotron radiation and inverse Compton scattering, respectively; the resulting {gamma}-ray flux for the shell is comparable to the detected one, only with a relatively larger density of about 2.8 cm{sup -3}. The VHE {gamma}-rays of HESS J1813-178 can be naturally explained to mainly originate from the nebula, although the contribution of the SNR shell becomes

  2. MULTIBAND NONTHERMAL EMISSION FROM THREE TeV SHELL-TYPE SUPERNOVA REMNANTS

    SciTech Connect

    Fang Jun; Tang Yunyong; Zhang Li

    2011-04-10

    Nonthermal radiative properties of three TeV shell-type supernova remnants (SNRs) RX J1713.7-3946, RX J0852.0-4622, and RCW 86, argued to be expanding into low-density hot bubbles created by the wind of the massive progenitor stars, are investigated based on a semi-analytical solution to diffusive acceleration at nonlinear shocks. In the model, a free-escape boundary upstream of the shock is used to mimic the escape of cosmic rays from the SNR, with the dynamic reaction of the self-generated magnetic field via resonant streaming instability on the shock taken into account. Origins of the {gamma}-rays from the three remnants are studied with appropriate parameters, and consistent results with the multiband observed fluxes are obtained within the nonlinear diffusive shock acceleration regime. The order of the resulting downstream magnetic field strength for the three SNRs is between 60 and 100 {mu}G, and the observed TeV {gamma}-rays are mainly produced via the decay of neutral {pi} mesons produced from the hadronic collisions.

  3. Non-thermal WIMPs as dark radiation

    SciTech Connect

    Queiroz, Farinaldo S.

    2014-06-24

    It has been thought that only light species could behave as radiation and account for the dark radiation observed recently by Planck, WMAP9, South Pole and ATACAMA telescopes. In this work we will show GeV scale WIMPs can plausibly account for the dark radiation as well. Heavy WIMPs might mimic the effect of a half neutrino species if some fraction of them are produced non-thermally after their thermal freeze-out. In addition, we will show how BBN, CMB and Structure Formation bounds might be circumvented.

  4. Nonthermal Radiation Processes in Interplanetary Plasmas

    NASA Astrophysics Data System (ADS)

    Chian, A. C. L.

    1990-11-01

    RESUMEN. En la interacci6n de haces de electrones energeticos con plasmas interplanetarios, se excitan ondas intensas de Langmuir debido a inestabilidad del haz de plasma. Las ondas Langmuir a su vez interaccio nan con fluctuaciones de densidad de baja frecuencia para producir radiaciones. Si la longitud de las ondas de Langmujr exceden las condicio nes del umbral, se puede efectuar la conversi5n de modo no lineal a on- das electromagneticas a traves de inestabilidades parametricas. As se puede excitar en un plasma inestabilidades parametricas electromagneticas impulsadas por ondas intensas de Langmuir: (1) inestabilidades de decaimiento/fusi5n electromagnetica impulsadas por una bomba de Lang- muir que viaja; (2) inestabilidades dobles electromagneticas de decai- miento/fusi5n impulsadas por dos bombas de Langrnuir directamente opues- tas; y (3) inestabilidades de dos corrientes oscilatorias electromagne- ticas impulsadas por dos bombas de Langmuir de corrientes contrarias. Se concluye que las inestabilidades parametricas electromagneticas in- ducidas por las ondas de Langmuir son las fuentes posibles de radiacio- nes no termicas en plasmas interplanetarios. ABSTRACT: Nonthermal radio emissions near the local electron plasma frequency have been detected in various regions of interplanetary plasmas: solar wind, upstream of planetary bow shock, and heliopause. Energetic electron beams accelerated by solar flares, planetary bow shocks, and the terminal shock of heliosphere provide the energy source for these radio emissions. Thus, it is expected that similar nonthermal radiation processes may be responsible for the generation of these radio emissions. As energetic electron beams interact with interplanetary plasmas, intense Langmuir waves are excited due to a beam-plasma instability. The Langmuir waves then interact with low-frequency density fluctuations to produce radiations near the local electron plasma frequency. If Langmuir waves are of sufficiently large

  5. Magnetic fields and nonthermal electromagnetic radiation of stars

    NASA Astrophysics Data System (ADS)

    Kryvdyk, Volodymyr

    2016-07-01

    The results of the astrophysical observations of the magnetic fields and the nonthermal electromagnetic radiation of stars and the mechanisms generation of the nonthermal electromagnetic radiation from the magnetized stars of different spectral classes on the different stages their evolution are present. Results of observations allow to calculate the plasma parameters and the magnetic fields in areas around magnetized stars where is generated given radiation and their change during stellar evolution.

  6. Detection of nonthermal continuum radiation in Saturn's magnetosphere

    SciTech Connect

    Kuth, W.S.; Scarf, F.L.; Sullivan, J.D.; Gurnett, D.A.

    1982-08-01

    A detailed analysis of high resolution wideband data from the Voyager 1 and 2 plasma wave receivers has revealed the presence of heretofore undiscovered nonthermal continuum radiation trapped within the Saturnian magnetosphere. The discovery of Saturnian trapped continuum radiation fills a disturbing void in the Saturnian radio spectrum. On the basis of observations at both the Earth and Jupiter it was expected that continuum radiation should be a pervasive signature of planetary magnetospheres in general. Special processing of the Voyager 1 plasma wave data at Saturn has now confirmed the existence of weak emissions that have a spectrum characteristic of trapped continuum radiation. Similar radiation was also detected by Voyager 2; however, in this case it is not certain that Saturn was the only source. Considerable evidence exists which suggests that Saturn may have been immersed in the Jovian tail during the Voyager 2 encounter, so that Jupiter may provide an additional source of the continuum radiation detected by Voyager 2.

  7. Nonthermal Particle Acceleration and Radiation in Relativistic Magnetic Reconnection

    NASA Astrophysics Data System (ADS)

    Werner, Gregory

    2015-11-01

    Many spectacular and violent phenomena in the high-energy universe exhibit nonthermal radiation spectra, from which we infer power-law energy distributions of the radiating particles. Relativistic magnetic reconnection, recognized as a leading mechanism of nonthermal particle acceleration, can efficiently transfer magnetic energy to energetic particles. We present a comprehensive particle-in-cell study of particle acceleration in 2D relativistic reconnection in both electron-ion and pair plasmas without guide field. We map out the power-law index α and the high-energy cutoff of the electron energy spectrum as functions of three key parameters: the system size (and initial layer length) L, the ambient plasma magnetization σ, and the ion/electron mass ratio (from 1 to 1836). We identify the transition between small- and large-system regimes: for small L, the system size affects the slope and extent of the high-energy spectrum, while for large enough L, α and the cutoff energy are independent of L. We compare high energy particle spectra and radiative (synchrotron and inverse Compton) signatures of the electrons, for pair and electron-ion reconnection. The latter cases maintain highly relativistic electrons, but include a range of different magnetizations yielding sub- to highly-relativistic ions. Finally, we show how nonthermal acceleration and radiative signatures alter when the radiation back-reaction becomes important. These results have important implications for assessing the promise and the limitations of relativistic reconnection as an astrophysically-important particle acceleration mechanism. This work is funded by NSF, DOE, and NASA.

  8. A 3-D multiband closure for radiation and neutron transfer moment models

    SciTech Connect

    Ripoll, J.-F. Wray, A.A.

    2008-02-01

    We derive a 3D multi-band moment model and its associated closure for radiation and neutron transfer. The new closure is analytical and nonlinear but very simple. Its derivation is based on the maximum entropy closure and assumes a Wien shape for the intensity when used in the Eddington tensor. In the multi-band approach, the opacity is re-arranged (binned) according to the opacity value. The multi-band model propagates identically all photons/neutrons having the same opacity. This has been found to be a good approximation on average since the transport is mostly determined by the opacities and less by the frequencies. This same concept is used to derive the closure. We prove on two complex test atmospheres (the solar atmosphere and an artificial atmosphere) that the closure we have derived has good accuracy. All approximations made in deriving the model have been carefully numerically checked and quantified.

  9. Quantum nonthermal radiation of nonstationary rotating de Sitter cosmological model

    NASA Astrophysics Data System (ADS)

    Meitei, Irom Ablu; Singh, T. Ibungochouba; Singh, K. Yugindro

    2014-08-01

    Using the Hamilton-Jacobi method a study of quantum nonthermal radiation of nonstationary rotating de Sitter cosmological model is carried out. It is shown that there exist seas of positive and negative energy states in the vicinity of the cosmological event horizon and there also exists a forbidden energy gap between the two seas. The forbidden energy gap vanishes on the surface of the cosmological event horizon so that the positive and negative energy levels overlap. The width of the forbidden energy gap and the energy of the particle at the cosmological event horizon are found to depend on the cosmological constant, the rotation parameter, positions of the particle and the cosmological event horizon, angular momentum of the particle, evaporation rate and shape of the cosmological event horizon. The tunneling probability of the emitted particles constituting Hawking radiation is also deduced for stationary nonrotating de Sitter cosmological model and the standard Hawking temperature is recovered.

  10. Parallel LC circuit model for multi-band absorption and preliminary design of radiative cooling.

    PubMed

    Feng, Rui; Qiu, Jun; Liu, Linhua; Ding, Weiqiang; Chen, Lixue

    2014-12-15

    We perform a comprehensive analysis of multi-band absorption by exciting magnetic polaritons in the infrared region. According to the independent properties of the magnetic polaritons, we propose a parallel inductance and capacitance(PLC) circuit model to explain and predict the multi-band resonant absorption peaks, which is fully validated by using the multi-sized structure with identical dielectric spacing layer and the multilayer structure with the same strip width. More importantly, we present the application of the PLC circuit model to preliminarily design a radiative cooling structure realized by merging several close peaks together. This omnidirectional and polarization insensitive structure is a good candidate for radiative cooling application. PMID:25607485

  11. Multi-band near-field radiative heat transfer between two anisotropic fishnet metamaterials

    NASA Astrophysics Data System (ADS)

    Bai, Yang; Jiang, Yongyuan; Liu, Linhua

    2015-06-01

    We study the near-field radiative heat transfer between two metal-insulator-metal sandwiched-like fishnet metamaterials (FMMs) by fluctuation electrodynamics. Results show that multi-band heat flux between the fishnet metamaterials is achieved, which is attributed to the thermally excited surface modes within the FMM. Apart from the electric response mode of the near-field heat flux, magnetic modes are also existed, which are related with the excitations of the surface plasmon polaritons (SPPs) propagating on the outer surface of metal (external SPPs) and along the inner metal-dielectric interface (internal SPPs). Moreover, we show that the electromagnetic parameters of this anisotropic fishnet metamaterial depend on the angles θ of the incident light when heating the fishnet metamaterial, and thus the overall effect of the anisotropic FMM parameters is considered to predict the near-field radiative heat transfer. Different external-SPPs and internal-SPPs modes are excited at different frequencies which is attributed to the anisotropic electromagnetic response of FMM, which open new frequency channels of the near-field radiative heat transfer. This kind of anisotropic metamaterial should assist in thermal management in nanoscale.

  12. Non-thermal continuous and modulated electromagnetic radiation fields effects on sleep EEG of rats.

    PubMed

    Mohammed, Haitham S; Fahmy, Heba M; Radwan, Nasr M; Elsayed, Anwar A

    2013-03-01

    In the present study, the alteration in the sleep EEG in rats due to chronic exposure to low-level non-thermal electromagnetic radiation was investigated. Two types of radiation fields were used; 900 MHz unmodulated wave and 900 MHz modulated at 8 and 16 Hz waves. Animals has exposed to radiation fields for 1 month (1 h/day). EEG power spectral analyses of exposed and control animals during slow wave sleep (SWS) and rapid eye movement sleep (REM sleep) revealed that the REM sleep is more susceptible to modulated radiofrequency radiation fields (RFR) than the SWS. The latency of REM sleep increased due to radiation exposure indicating a change in the ultradian rhythm of normal sleep cycles. The cumulative and irreversible effect of radiation exposure was proposed and the interaction of the extremely low frequency radiation with the similar EEG frequencies was suggested. PMID:25685416

  13. Hawking radiation in the ghost condensate is nonthermal

    SciTech Connect

    Feldstein, Brian

    2008-09-15

    We consider a Schwarzschild black hole immersed in a ghost condensate background. It is shown that the Hawking radiation in the quanta of small perturbations around this background is highly suppressed - in particular, it is not given by a thermal spectrum. This result is in accord with observations that such black holes can be used to violate the generalized second law of thermodynamics, and thus cannot have a standard entropy/area relation.

  14. Nonthermal WIMPs as ``dark radiation'' in light of ATACAMA, SPT, WMAP9, and Planck

    NASA Astrophysics Data System (ADS)

    Kelso, Chris; Profumo, Stefano; Queiroz, Farinaldo S.

    2013-07-01

    The Planck and WMAP9 satellites, as well as the ATACAMA and South Pole telescopes, have recently presented results on the angular power spectrum of the comic microwave background. Data tentatively point to the existence of an extra radiation component in the early Universe. Here, we show that this extra component can be mimicked by ordinary weakly interacting massive particle dark matter particles whose majority is cold, but with a small fraction being nonthermally produced in a relativistic state. We present a few example theories where this scenario is explicitly realized and explore the relevant parameter space consistent with big bang nucleosynthesis, cosmic microwave background, and structure formation bounds.

  15. Dynamics of ultrashort pulsed laser radiation induced non-thermal ablation of graphite

    NASA Astrophysics Data System (ADS)

    Reininghaus, M.; Kalupka, C.; Faley, O.; Holtum, T.; Finger, J.; Stampfer, C.

    2014-12-01

    We report on the dependence of a laser radiation induced ablation process of graphite on the applied pulse duration of ultrashort pulsed laser radiation smaller than 4 ps. The emerging so-called non-thermal ablation process of graphite has been confirmed to be capable to physically separate ultrathin graphitic layers from the surface of pristine graphite bulk crystal. This allows the deposition of ablated graphitic flakes on a substrate in the vicinity of the target. The observed ablation threshold determined at different pulse durations shows a modulation, which we ascribe to lattice motions along the c axis that are theoretically predicted to induce the non-thermal ablation process. In a simple approach, the ablation threshold can be described as a function of the energy penetration depth and the absorption of the applied ultrashort pulsed laser radiation. Based on the analysis of the pulse duration dependence of those two determining factors and the assumption of an invariant ablation process, we are able to reproduce the pulse duration dependence of the ablation threshold. Furthermore, the observed pulse duration dependences confirm the assumption of a fast material specific response of graphite target subsequent to optical excitation within the first 2 ps.

  16. Nonthermal radiative transfer of oxygen 98.9 nm ultraviolet emission: Solving an old mystery

    NASA Astrophysics Data System (ADS)

    Hubert, B.; Gérard, J.-C.; Shematovich, V. I.; Bisikalo, D. V.; Chakrabarti, S.; Gladstone, G. R.

    2015-12-01

    Sounding rocket measurements conducted in 1988 under high solar activity conditions revealed that the intensity of thermospheric OI emissions at 98.9 nm presents an anomalous vertical profile, showing exospheric intensities much higher than expected from radiative transfer model results, which included the known sources of excited oxygen. All attempts based on modeling of the photochemical processes and radiative transfer were unable to account for the higher than predicted brightnesses. More recently, the SOHO-Solar Ultraviolet Measurements of Emitted Radiation instrument measured the UV solar flux at high-spectral resolution, revealing the importance of a significant additional source of oxygen emission at 98.9 nm that had not been accounted for before. In this study, we simulate the radiative transfer of the OI-98.9 nm multiplet, including the photochemical sources of excited oxygen, the resonant scattering of solar photons, and the effects of nonthermal atoms, i.e., a population of fast-moving oxygen atoms in excess of the Maxwellian distribution. Including resonance scattering of the 98.9 nm solar multiplet, we find good agreement with the previous sounding rocket observation. The inclusion of a nonthermal oxygen population with a consistent increase of the total density produces a larger intensity at high altitude that apparently better accounts for the observation, but such a correction cannot be demonstrated given the uncertainties of the observations. A good agreement between model and sounding rocket observation is also found with the triplet at 130.4 nm. We further investigate the radiative transfer of the OI-98.9 nm multiplet and the oxygen emissions at 130.4 and 135.6 nm using observations from the STP78-1 satellite. We find a less satisfying agreement between the model and the STP78-1 data that can be accounted for by scaling the modeled intensity within a range acceptable given the uncertainties on the STP78-1 absolute calibration.

  17. Non-thermal effects of 94 GHz radiation on bacterial metabolism

    NASA Astrophysics Data System (ADS)

    Raitt, Brittany J.

    Bacillus subtilis, Escherichia coli, Staphylococcus aureus, and Klebsiella pneumoniae were used to investigate the non-thermal effects of terahertz (THz) radiation exposure on bacterial cells. The THz source used was a 94 GHz (0.94 THz) Millitech Gunn Diode Oscillator with a power density of 1.3 mW/cm2. The cultures were placed in the middle sixty wells of two 96-well microplates, one serving as the experimental plate and one serving as a control. The experimental plate was placed on the radiation source for either two, eighteen, or twenty-four hours and the metabolism of the cells was measured in a spectrophotometer using the tetrazolium dye XTT. The results showed no consistent significant differences in either the growth rates or the metabolism of any of the bacterial species at this frequency and power density.

  18. Radio frequency radiation causes no nonthermal damage in enzymes and living cells.

    PubMed

    Fortune, Jennifer A; Wu, Bae-Ian; Klibanov, Alexander M

    2010-01-01

    The ability of radio frequency radiation (RFR) to exert irreversible nonthermal (i.e., not caused by accompanying heat) effects on biologics has been widely debated due to a relative paucity of comprehensive critical details in published reports dealing with this issue. In this study, we used rigorous control over experimental conditions to determine whether continuous RFR nonthermally affects commercially important enzymes and live bacterial and human cells using three most commonly used frequencies in current RF identification technology, namely 2.45 GHz, 915 MHz, and 13.56 MHz. Diverse biological samples were exposed to RFR under deliberately harsh conditions to increase the likelihood of observing such effects should they exist. Enzymatic activities of horseradish peroxidase and β-galactosidase in aqueous solution exhibited no statistically discernable consequences of even very intense RFR. Likewise, with putative thermal effects excluded, the viabilities of bacteria (both gram-positive and gram-negative) and of human cells were not detectably compromised by such an RFR exposure. PMID:20572294

  19. NONTHERMAL RADIATION FROM SUPERNOVA REMNANTS: EFFECTS OF MAGNETIC FIELD AMPLIFICATION AND PARTICLE ESCAPE

    SciTech Connect

    Kang, Hyesung; Jones, T. W.; Edmon, Paul P. E-mail: twj@msi.umn.edu

    2013-11-01

    We explore nonlinear effects of wave-particle interactions on the diffusive shock acceleration (DSA) process in Type Ia-like supernova remnant (SNR) blast waves by implementing phenomenological models for magnetic field amplification (MFA), Alfvénic drift, and particle escape in time-dependent numerical simulations of nonlinear DSA. For typical SNR parameters, the cosmic-ray (CR) protons can be accelerated to PeV energies only if the region of amplified field ahead of the shock is extensive enough to contain the diffusion lengths of the particles of interest. Even with the help of Alfvénic drift, it remains somewhat challenging to construct a nonlinear DSA model for SNRs in which of the order of 10% of the supernova explosion energy is converted into CR energy and the magnetic field is amplified by a factor of 10 or so in the shock precursor, while, at the same time, the energy spectrum of PeV protons is steeper than E {sup –2}. To explore the influence of these physical effects on observed SNR emission, we also compute the resulting radio-to-gamma-ray spectra. Nonthermal emission spectra, especially in X-ray and gamma-ray bands, depend on the time-dependent evolution of the CR injection process, MFA, and particle escape, as well as the shock dynamic evolution. This result comes from the fact that the high-energy end of the CR spectrum is composed of particles that are injected in the very early stages of the blast wave evolution. Thus, it is crucial to better understand the plasma wave-particle interactions associated with collisionless shocks in detailed modeling of nonthermal radiation from SNRs.

  20. Hawking non-thermal and thermal radiations of Schwarzschild anti-de Sitter black hole by Hamilton-Jacobi method

    NASA Astrophysics Data System (ADS)

    Rahman, M. Atiqur; Hossain, M. Ilias

    2013-06-01

    The massive particles tunneling method has been used to investigate the Hawking non-thermal and purely thermal radiations of Schwarzschild Anti-de Sitter (SAdS) black hole. Considering the spacetime background to be dynamical, incorporate the self-gravitation effect of the emitted particles the imaginary part of the action has been derived from Hamilton-Jacobi equation. Using the conservation laws of energy and angular momentum we have showed that the non-thermal and purely thermal tunneling rates are related to the change of Bekenstein-Hawking entropy and the derived emission spectrum deviates from the pure thermal spectrum. The result obtained for SAdS black hole is also in accordance with Parikh and Wilczek's opinion and gives a correction to the Hawking radiation of SAdS black hole.

  1. NONTHERMAL RADIATION OF YOUNG SUPERNOVA REMNANTS: THE CASE OF RX J1713.7-3946

    SciTech Connect

    Zirakashvili, V. N.; Aharonian, F. A.

    2010-01-10

    A new numerical code, designed for the detailed numerical treatment of nonlinear diffusive shock acceleration, is used for the modeling of particle acceleration and radiation in young supernova remnants (SNRs). The model is based on spherically symmetric hydrodynamic equations complemented with transport equations for relativistic particles. For the first time, the acceleration of electrons and protons by both forward and reverse shocks is studied through detailed numerical calculations. We model the energy spectra and spatial distributions of nonthermal emission of the young SNR RX J1713.7-3946 and compare the calculations with the spectral and morphological properties of this object obtained in broad energy band from radio to very high-energy gamma rays. We discuss the advantages and shortcomings of the so-called hadronic and leptonic models, which assume that the observed TeV gamma-ray emission is produced by accelerated protons and electrons, respectively. We discuss also a 'composite' scenario when the gamma-ray flux from the main parts of the shell has inverse Compton origin, but with a non-negligible contribution of hadronic origin from dense clouds interacting with the shell.

  2. Theory-Agnostic Constraints on Black-Hole Dipole Radiation with Multiband Gravitational-Wave Astrophysics

    NASA Astrophysics Data System (ADS)

    Barausse, Enrico; Yunes, Nicolás; Chamberlain, Katie

    2016-06-01

    The aLIGO detection of the black-hole binary GW150914 opens a new era for probing extreme gravity. Many gravity theories predict the emission of dipole gravitational radiation by binaries. This is excluded to high accuracy in binary pulsars, but entire classes of theories predict this effect predominantly (or only) in binaries involving black holes. Joint observations of GW150914-like systems by aLIGO and eLISA will improve bounds on dipole emission from black-hole binaries by 6 orders of magnitude relative to current constraints, provided that eLISA is not dramatically descoped.

  3. Theory-Agnostic Constraints on Black-Hole Dipole Radiation with Multiband Gravitational-Wave Astrophysics.

    PubMed

    Barausse, Enrico; Yunes, Nicolás; Chamberlain, Katie

    2016-06-17

    The aLIGO detection of the black-hole binary GW150914 opens a new era for probing extreme gravity. Many gravity theories predict the emission of dipole gravitational radiation by binaries. This is excluded to high accuracy in binary pulsars, but entire classes of theories predict this effect predominantly (or only) in binaries involving black holes. Joint observations of GW150914-like systems by aLIGO and eLISA will improve bounds on dipole emission from black-hole binaries by 6 orders of magnitude relative to current constraints, provided that eLISA is not dramatically descoped. PMID:27367380

  4. Time delays in the nonthermal radiation of solar flares according to observations of the CORONAS-F satellite

    NASA Astrophysics Data System (ADS)

    Tsap, Yu. T.; Stepanov, A. V.; Kashapova, L. K.; Myagkova, I. N.; Bogomolov, A. V.; Kopylova, Yu. G.; Goldvarg, T. B.

    2016-07-01

    In 2001-2003, the X-ray and microwave observations of ten solar flares of M- and X-classes were carried out by the CORONAS-F orbital station, the RSTN Sun service, and Nobeyama radio polarimeters. Based on these observations, a correlation analysis of time profiles of nonthermal radiation was performed. On average, hard X-ray radiation outstrips the microwave radiation in 9 events, i.e., time delays are positive. The appearance of negative delays is associated with effective scattering of accelerated electrons in pitch angles, where the length of the free path of a particle is less than the half-length of a flare loop. The additional indications are obtained in favor of the need to account for the effect of magnetic mirrors on the dynamics of energetic particles in the coronal arches.

  5. Non-thermal Radiation from Collisions of Compact Objects with Intermediate-scale Jets in Active Galaxies

    NASA Astrophysics Data System (ADS)

    Bednarek, W.; Banasiński, P.

    2015-07-01

    Massive black holes in active galaxies are immersed in huge concentrations of late-type stars in the galactic bulges and also early-type massive stars in the nuclear stellar clusters, which are additionally surrounded by quasi-spherical halos on a scale of several kpc that contain from a few hundred up to several thousand globular clusters (GCs). It is expected that significant numbers of red giant stars, massive stars, and also GCs can move through the jet expelled from the central engine of the active galaxy. We consider collisions of stars from the galactic bulge, nuclear cluster, and GCs with the jet plasma. As a result of such collisions, multiple shocks are expected to appear in the jet around these compact objects. Therefore, the plasma in the kpc-scale jet can be significantly disturbed. We show that particles can be accelerated on these shocks up to multi-TeV energies. TeV leptons emit synchrotron radiation, extending up to X-ray energies, and also comptonize radiation produced in a stellar cluster and also the microwave background radiation to TeV γ-ray energies. We show that such non-thermal radiation is likely to be detectable from the intermediate-scale jets of nearby active galaxies for a reasonable number of stars and GCs immersed within the jet. As an example, we calculate the expected non-thermal emission in X-ray and gamma-ray energies from the nearby radio galaxy Cen A, from which steady gamma-ray emission with a complex spectrum has recently been reported by Fermi and the HESS Observatories.

  6. The quantum nonthermal radiation and horizon surface gravity of an arbitrarily accelerating black hole with electric charge and magnetic charge

    NASA Astrophysics Data System (ADS)

    Xie, Zhi-Kun; Pan, Wei-Zhen; Yang, Xue-Jun

    2013-03-01

    Using a new tortoise coordinate transformation, we discuss the quantum nonthermal radiation characteristics near an event horizon by studying the Hamilton-Jacobi equation of a scalar particle in curved space-time, and obtain the event horizon surface gravity and the Hawking temperature on that event horizon. The results show that there is a crossing of particle energy near the event horizon. We derive the maximum overlap of the positive and negative energy levels. It is also found that the Hawking temperature of a black hole depends not only on the time, but also on the angle. There is a problem of dimension in the usual tortoise coordinate, so the present results obtained by using a correct-dimension new tortoise coordinate transformation may be more reasonable.

  7. Hawking effect and quantum nonthermal radiation of an arbitrarily accelerating charged black hole using a new tortoise coordinate transformation

    NASA Astrophysics Data System (ADS)

    Pan, Wei-Zhen; Yang, Xue-Jun; Xie, Zhi-Kun

    2011-04-01

    Using a new tortoise coordinate transformation, this paper investigates the Hawking effect from an arbitrarily accelerating charged black hole by the improved Damour—Ruffini method. After the tortoise coordinate transformation, the Klein—Gordon equation can be written as the standard form at the event horizon. Then extending the outgoing wave from outside to inside of the horizon analytically, the surface gravity and Hawking temperature can be obtained automatically. It is found that the Hawking temperatures of different points on the surface are different. The quantum nonthermal radiation characteristics of a black hole near the event horizon is also discussed by studying the Hamilton—Jacobi equation in curved spacetime and the maximum overlap of the positive and negative energy levels near the event horizon is given. There is a dimensional problem in the standard tortoise coordinate and the present results may be more reasonable.

  8. Rapid temporal evolution of radiation from non-thermal electrons in solar flares

    NASA Technical Reports Server (NTRS)

    Lu, Edward T.; Petrosian, Vahe

    1987-01-01

    Solutions of the time dependent Fokker-Planck equation was found for accelerated electrons undergoing Coulomb collisions in a magnetized, fully ionized plasma. An exact solution was found for arbitrary pitch angle and energy distribution in a uniform background plasma. Then, for an inhomogeneous plasma, a solution was found for particles with small pitch angles. These solutions were used to calculate the temporal evolution of bremsstrahlung x-rays from short bursts of nonthermal electron beams, and these spectra were compared with observed high time resolution spectra of short timescale solar hard x-ray bursts. It is shown that the observed softening in time of the spectra rules out a homogeneous background and therefore the possibility of electrons being confined to the corona either because of converging magnetic field or high densities. The inhomogeneous solution was also applied to a model with constant coronal density and exponentially rising chromospheric density. The spectra are shown to be consistent with that produced by a collimated beam of electrons accelerated in the corona with certain given conditions. These conditions could be violated if large pitch angle electrons are present.

  9. Hawking non-thermal and thermal radiations of Reissner Nordström anti-de Sitter black hole by Hamilton-Jacobi method

    NASA Astrophysics Data System (ADS)

    Ilias Hossain, M.; Atiqur Rahman, M.

    2013-09-01

    We have investigated Hawking non-thermal and purely thermal Radiations of Reissner Nordström anti-de Sitter (RNAdS) black hole by massive particles tunneling method. The spacetime background has taken as dynamical, incorporate the self-gravitation effect of the emitted particles the imaginary part of the action has derived from Hamilton-Jacobi equation. We have supposed that energy and angular momentum are conserved and have shown that the non-thermal and thermal tunneling rates are related to the change of Bekenstein-Hawking entropy and the derived emission spectrum deviates from the pure thermal spectrum. The results for RNAdS black hole is also in the same manner with Parikh and Wilczek's opinion and explored the new result for Hawking radiation of RNAdS black hole.

  10. Multiband radiometer for field research

    NASA Technical Reports Server (NTRS)

    Robinson, B. F.; Bauer, M. E.; Dewitt, D. P.; Silva, L. F.; Vanderbilt, V. C.

    1979-01-01

    A multiband radiometer for field research with 8 bands between 0.4 and 12.5 micrometers is described. The data acquisition system will record the results from the radiometer, a precision radiation thermometer, and ancillary sources. The radiometer and data handling systems will be adaptable to helicopter, truck, to tripod platforms; the system will also be suitable for portable hand-held operation. The general characteristics of this system are that it will be (1) inexpensive to acquire, maintain, and operate, (2) simple to calibrate, (3) complete with data handling hardware and software, and (4) well-documented for use by researchers.

  11. Non-thermal effects of terahertz radiation on gene expression in mouse stem cells

    PubMed Central

    Alexandrov, Boian S.; Rasmussen, Kim Ø.; Bishop, Alan R.; Usheva, Anny; Alexandrov, Ludmil B.; Chong, Shou; Dagon, Yossi; Booshehri, Layla G.; Mielke, Charles H.; Phipps, M. Lisa; Martinez, Jennifer S.; Chen, Hou-Tong; Rodriguez, George

    2011-01-01

    Abstract In recent years, terahertz radiation sources are increasingly being exploited in military and civil applications. However, only a few studies have so far been conducted to examine the biological effects associated with terahertz radiation. In this study, we evaluated the cellular response of mesenchymal mouse stem cells exposed to THz radiation. We apply low-power radiation from both a pulsed broad-band (centered at 10 THz) source and from a CW laser (2.52 THz) source. Modeling, empirical characterization, and monitoring techniques were applied to minimize the impact of radiation-induced increases in temperature. qRT-PCR was used to evaluate changes in the transcriptional activity of selected hyperthermic genes. We found that temperature increases were minimal, and that the differential expression of the investigated heat shock proteins (HSP105, HSP90, and CPR) was unaffected, while the expression of certain other genes (Adiponectin, GLUT4, and PPARG) showed clear effects of the THz irradiation after prolonged, broad-band exposure. PMID:21991556

  12. Terahertz radiation induces non-thermal structural changes associated with Fröhlich condensation in a protein crystal

    PubMed Central

    Lundholm, Ida V.; Rodilla, Helena; Wahlgren, Weixiao Y.; Duelli, Annette; Bourenkov, Gleb; Vukusic, Josip; Friedman, Ran; Stake, Jan; Schneider, Thomas; Katona, Gergely

    2015-01-01

    Whether long-range quantum coherent states could exist in biological systems, and beyond low-temperature regimes where quantum physics is known to be applicable, has been the subject to debate for decades. It was proposed by Fröhlich that vibrational modes within protein molecules can order and condense into a lowest-frequency vibrational mode in a process similar to Bose-Einstein condensation, and thus that macroscopic coherence could potentially be observed in biological systems. Despite the prediction of these so-called Fröhlich condensates almost five decades ago, experimental evidence thereof has been lacking. Here, we present the first experimental observation of Fröhlich condensation in a protein structure. To that end, and to overcome the challenges associated with probing low-frequency molecular vibrations in proteins (which has hampered understanding of their role in proteins' function), we combined terahertz techniques with a highly sensitive X-ray crystallographic method to visualize low-frequency vibrational modes in the protein structure of hen-egg white lysozyme. We found that 0.4 THz electromagnetic radiation induces non-thermal changes in electron density. In particular, we observed a local increase of electron density in a long α-helix motif consistent with a subtle longitudinal compression of the helix. These observed electron density changes occur at a low absorption rate indicating that thermalization of terahertz photons happens on a micro- to milli-second time scale, which is much slower than the expected nanosecond time scale due to damping of delocalized low frequency vibrations. Our analyses show that the micro- to milli-second lifetime of the vibration can only be explained by Fröhlich condensation, a phenomenon predicted almost half a century ago, yet never experimentally confirmed. PMID:26798828

  13. Spectral evolution of non-thermal electron distributions in intense radiation fields

    NASA Astrophysics Data System (ADS)

    Manolakou, K.; Horns, D.; Kirk, J. G.

    2007-11-01

    Context: Models of many astrophysical gamma-ray sources assume they contain a homogeneous distribution of electrons that are injected as a power law in energy and evolve by interacting with radiation fields, magnetic fields, and particles in the source and by escaping. This problem is particularly complicated if the radiation fields have higher energy density than the magnetic field and are sufficiently energetic that inverse Compton scattering is not limited to the Thomson regime. Aims: We present a simple, time-dependent, semi-analytical solution to the electron kinetic equation that treats both continuous and impulsive injection, cooling via synchrotron and inverse Compton radiation (taking Klein-Nishina effects into account), and energy-dependent particle escape. We used this solution to calculate the temporal evolution of the multi-wavelength spectrum of systems where energetic electrons cool in intense photon fields. Methods: The kinetic equation for an arbitrary, time-dependent source function is solved by the method of Laplace transformations. Using an approximate expression for the energy-loss rate that takes synchrotron and inverse Compton losses into account, including Klein-Nishina effects for scattering off an isotropic photon field with either a power-law or black-body distribution, we find explicit expressions for the cooling time and escape probability of individual electrons. This enables the full, time-dependent solution to be reduced to a single quadrature. From the electron distribution, we then construct the time-dependent, multi-wavelength emission spectrum. Results: We compare our solutions with several limiting cases and discuss the general appearance and temporal behaviour of spectral features (i.e., cooling breaks, bumps, etc.). As a specific example, we model the broad-band energy spectrum of the open stellar association Westerlund-2 at different times of its evolution, and compare it with observations. The model calculation matches the

  14. Nonthermal Radiation of Young Supernova Remnants: The Case of CAS A

    NASA Astrophysics Data System (ADS)

    Zirakashvili, V. N.; Aharonian, F. A.; Yang, R.; Oña-Wilhelmi, E.; Tuffs, R. J.

    2014-04-01

    The processes responsible for the broadband radiation of the young supernova remnant Cas A are explored by using a new code that is designed for a detailed treatment of the diffusive shock acceleration of particles in the nonlinear regime. The model is based on spherically symmetric hydrodynamic equations complemented with transport equations for relativistic particles. Electrons, protons, and the oxygen ions accelerated by forward and reverse shocks are included in the numerical calculations. We show that the available multi-wavelength observations in the radio, X-ray, and gamma-ray bands can be best explained by invoking particle acceleration by both forward and reversed shocks. Although the TeV gamma-ray observations can be interpreted by interactions of both accelerated electrons and protons/ions, the measurements by Fermi Large Area Telescope at energies below 1 GeV give a tentative preference to the hadronic origin of gamma-rays. Then, the acceleration efficiency in this source, despite the previous claims, should be very high; 25% of the explosion energy (or approximately 3 × 1050 erg) should already be converted to cosmic rays, mainly by the forward shock. At the same time, the model calculations do not provide extension of the maximum energy of accelerated protons beyond 100 TeV. In this model, the acceleration of electrons is dominated by the reverse shock; the required 1048 erg can be achieved under the assumption that the injection of electrons (positrons) is supported by the radioactive decay of 44Ti.

  15. Nonthermal radiation of young supernova remnants: The case of Cas A

    SciTech Connect

    Zirakashvili, V. N.; Aharonian, F. A.; Yang, R.; Oña-Wilhelmi, E.; Tuffs, R. J.

    2014-04-20

    The processes responsible for the broadband radiation of the young supernova remnant Cas A are explored by using a new code that is designed for a detailed treatment of the diffusive shock acceleration of particles in the nonlinear regime. The model is based on spherically symmetric hydrodynamic equations complemented with transport equations for relativistic particles. Electrons, protons, and the oxygen ions accelerated by forward and reverse shocks are included in the numerical calculations. We show that the available multi-wavelength observations in the radio, X-ray, and gamma-ray bands can be best explained by invoking particle acceleration by both forward and reversed shocks. Although the TeV gamma-ray observations can be interpreted by interactions of both accelerated electrons and protons/ions, the measurements by Fermi Large Area Telescope at energies below 1 GeV give a tentative preference to the hadronic origin of gamma-rays. Then, the acceleration efficiency in this source, despite the previous claims, should be very high; 25% of the explosion energy (or approximately 3 × 10{sup 50} erg) should already be converted to cosmic rays, mainly by the forward shock. At the same time, the model calculations do not provide extension of the maximum energy of accelerated protons beyond 100 TeV. In this model, the acceleration of electrons is dominated by the reverse shock; the required 10{sup 48} erg can be achieved under the assumption that the injection of electrons (positrons) is supported by the radioactive decay of {sup 44}Ti.

  16. X-class Solar Flare Energy Partition into Radiative, Non-Thermal Acceleration of Electrons and Peak Thermal Plasma Components - Methodology and Results

    NASA Astrophysics Data System (ADS)

    Moore, Christopher S.; Chamberlin, Phillip; Dennis, Brian R.; Hock, Rachel

    2015-08-01

    Solar flares are among the most energetic processes in the solar system. X-class flares are the largest and can convert up to 1033 ergs of magnetic energy into the acceleration of charged particles and the heating of plasma. They are often accompanied by coronal mass ejections (CMEs). We discuss the methodology and results of the energy partition into three main components: (1) radiative energy, (2) non-thermal acceleration of electrons, and (3) the peak thermal energy content, for a subset of the largest eruptive events from Solar Cycle 23, as derived from satellite observations and empirical models. The bolometric energy content is on the order of 1031 - 1032 ergs and is extracted from Total Solar Irradiance (TSI) measurements by the Total Irradiance Monitor (TIM) onboard the SOlar Radiation and Climate Experiment (SORCE). The Vacuum Ultraviolet (VUV) contribution of the total radiative output is obtained by implementing the Flare Irradiance Spectral Model (FISM). Furthermore, we partition the radiative release into impulsive and gradual phases. X-ray spectra from the Ramaty High Energy Solar Spectroscopic Imager (RHESSI) are used to deduce the energy in the non-thermal accelerated electrons, generally found to be 1031 -1032 ergs, and the peak thermal energy content of around 1030 - 1031 ergs. Aside from the CME kinetic energy, these three components contain a substantial amount of the initial available magnetic energy.

  17. Risk Analysis for Nonthermal process interventions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Over the last few years a number of nonthermal process interventions including ionizing radiation and ultraviolet light, high pressure processing, pulsed-electric and radiofrequency electric fields, microwave and infrared technologies, bacteriophages, etc. have been approved by regulatory agencies, ...

  18. Multi-band gap and new solar cell options workshop

    NASA Technical Reports Server (NTRS)

    Hutchby, J.; Timmons, M.; Olson, J. M.

    1993-01-01

    Discussions of the multi-band gap (MBG) and new solar cell options workshop are presented. Topics discussed include: greater than 2 terminal cells; radiation damage preventing development of MBG cells for space; lattice matching; measurement of true performance; future of II-VI materials in MBG devices; and quaternaries.

  19. Changes in the spectral composition of animal-brain electrical activity under the influence of nonthermal millimeter-wave radiation on acupuncture points

    NASA Astrophysics Data System (ADS)

    Khramov, R. N.; Vorob'ev, V. V.

    1994-01-01

    The frequency spectra (0 26 Hz) of electrograms (EG) of the preoptic region of the hypothalamus were studied in chronic experiments on nine awake rabbits under the influence of nonthermal millimeter-band (55 75 GHz) electromagnetic fields on various acupuncture points: I) the auricular “heart” point (after F. G. Portnov); II) the cranial acupoint (TR-20; the “hypothalamus” point after R. Voll); and III) the “longevity” acupoint (E-36). Irradiation of point I was accompanied by significant suppression of hypothalamic electrical activity at 5 and 16 Hz and enhancement at 7 8, 12, and 26 Hz. Irradiation of point II had similar but less-prominent effects at 7 8 and 12 Hz. Minimal EG changes were observed with exposure of point III. The probabilities of significant changes in EG spectra for irradiation of points I, II, and III were, respectively, 31%, 21%, and 5% (p<0.05, U-criterion). These results suggest that acupuncture points I and II are more sensitive to millimeter-band radiation than is point III. The presence of individual characteristics of the effects and their change after stress to sign inversion were shown in rat experiments in which the acupuncture points were irradiated.

  20. Heating and ionization of stellar chromospheres by nonthermal proton beams: Implications for impulsive phase, redshifted Lyman-alpha radiation in stellar flares

    NASA Technical Reports Server (NTRS)

    Brosius, Jeffrey W.; Robinson, Richard D.; Maran, Stephen P.

    1995-01-01

    We investigate the physical basis for the timescale of impulsive-phase, redshifted Lyman-alpha emission in stellar flares on the assumption that it is determined by energy losses in a nonthermal proton beam that is penetrating the chromosphere from above. The temporal evolution of ionization and heating in representative model chromospheres subjected to such beams is calculated. The treatment of 'stopping' of beam protons takes into account their interactions with (1) electrons bound in neutral hydrogen, (2) nuclei of neutral hydrogen, (3) free electrons, and (4) ambient thermal protons. We find that, for constant incident beam flux, the system attains an equilibrium with the beam energy input to the chromosphere balanced by radiative losses. In equilibrium, the beam penetration depth is constant, and erosion of the chromosphere ceases. If the redshifted, impulsive-phase stellar flare Lyman-alpha emission is produced by downstreaming hydrogen formed through charge exchange between beam protons and ambient hydrogen, then the emission should end when the beam no longer reaches neutral hydrogen. The durations of representative emission events calculated on this assumption range from 0.1 to 14 s. The stronger the beam, the shorter the timescale over which the redshifted Lyman-alpha emission can be observed.

  1. Changes in the spectral composition of animal-brain electrical activity under the influence of nonthermal millimeter-wave radiation on acupuncture points

    SciTech Connect

    Khramov, R.N.; Vorob`ev, V.V.

    1994-07-01

    The frequency spectra (0-26 Hz) of electrograms (EG) of the preoptic region of the hypothalamus were studied in chronic experiments on nine awake rabbits under the influence of nonthermal millimeter-bank (55-75 GHz) electromagnetic fields on various acupuncture points: (I) the auricular {open_quotes}heart{close_quotes} point (after F. G. Portnov); (II) the cranial acupoint (TR-20; the {open_quotes}hypothalamus{close_quotes} point after R. Voll); and (III) the {open_quotes}longevity{close_quotes} acupoint (E-36). Irradiation of point I was accompanied by significant suppression of hypothalamic electrical activity at 5 and 16 Hz and enhancement at 7-8, 12, and 26 Hz. Irradiation of point II, and III were, respectively, 31%, 21%, and 5% (p < 0.05, U-criterion). These results suggest that acupuncture points I and II are more sensitive to millimeter-band radiation than is point III. The presence of individual characteristics of the effects and their change after stress to sign inversion were shown in rat experiments in which the acupuncture points were irradiated.

  2. Signatures of nonthermal melting.

    PubMed

    Zier, Tobias; Zijlstra, Eeuwe S; Kalitsov, Alan; Theodonis, Ioannis; Garcia, Martin E

    2015-09-01

    Intense ultrashort laser pulses can melt crystals in less than a picosecond but, in spite of over thirty years of active research, for many materials it is not known to what extent thermal and nonthermal microscopic processes cause this ultrafast phenomenon. Here, we perform ab-initio molecular-dynamics simulations of silicon on a laser-excited potential-energy surface, exclusively revealing nonthermal signatures of laser-induced melting. From our simulated atomic trajectories, we compute the decay of five structure factors and the time-dependent structure function. We demonstrate how these quantities provide criteria to distinguish predominantly nonthermal from thermal melting. PMID:26798822

  3. Signatures of nonthermal melting

    PubMed Central

    Zier, Tobias; Zijlstra, Eeuwe S.; Kalitsov, Alan; Theodonis, Ioannis; Garcia, Martin E.

    2015-01-01

    Intense ultrashort laser pulses can melt crystals in less than a picosecond but, in spite of over thirty years of active research, for many materials it is not known to what extent thermal and nonthermal microscopic processes cause this ultrafast phenomenon. Here, we perform ab-initio molecular-dynamics simulations of silicon on a laser-excited potential-energy surface, exclusively revealing nonthermal signatures of laser-induced melting. From our simulated atomic trajectories, we compute the decay of five structure factors and the time-dependent structure function. We demonstrate how these quantities provide criteria to distinguish predominantly nonthermal from thermal melting. PMID:26798822

  4. The non-thermal superbubble in IC 10: the generation of cosmic ray electrons caught in the act

    NASA Astrophysics Data System (ADS)

    Heesen, Volker; Brinks, Elias; Krause, Martin G. H.; Harwood, Jeremy J.; Rau, Urvashi; Rupen, Michael P.; Hunter, Deidre A.; Chyży, Krzysztof T.; Kitchener, Ged

    2015-02-01

    Superbubbles are crucial for stellar feedback, with supposedly high (of the order of 10 per cent) thermalization rates. We combined multiband radio continuum observations from the Very Large Array (VLA) with Effelsberg data to study the non-thermal superbubble (NSB) in IC 10, a starburst dwarf irregular galaxy in the Local Group. Thermal emission was subtracted using a combination of Balmer Hα and VLA 32 GHz continuum maps. The bubble's non-thermal spectrum between 1.5 and 8.8 GHz displays curvature and can be well fitted with a standard model of an ageing cosmic ray electron population. With a derived equipartition magnetic field strength of 44 ± 8 μG, and measuring the radiation energy density from Spitzer MIPS maps as 5 ± 1 × 10-11 erg cm-3, we determine, based on the spectral curvature, a spectral age of the bubble of 1.0 ± 0.3 Myr. Analysis of the LITTLE THINGS H I data cube shows an expanding H I hole with 100 pc diameter and a dynamical age 3.8 ± 0.3 Myr, centred to within 16 pc on IC 10 X-1, a massive stellar mass black hole (M > 23 M⊙). The results are consistent with the expected evolution for a superbubble with a few massive stars, where a very energetic event like a Type Ic supernova/hypernova has taken place about 1 Myr ago. We discuss alternatives to this interpretation.

  5. Comparison of the thermal and nonthermal radiation characteristics of Jupiter at 6, 11, and 21 cm with model calculations

    NASA Technical Reports Server (NTRS)

    De Pater, I.; Kenderdine, S.; Dickel, J. R.

    1982-01-01

    Four different data sets on Jupiter, one at 6, one at 11, and two at 21 cm, are compared to each other and with the synchrotron radiation model of the magnetosphere developed by de Pater (1981). The model agrees with all these data sets, and hence was used to derive and interpret the characteristics of the thermal radiation component at all three wavelengths. The disk temperatures are 233 + or - 17, 280 + or - 20, and 340 + or - 26 K at 6, 11, and 21 cm, respectively. A comparison of the data with atmospheric model calculations strongly suggests that the disk is uniform at 6 and 11 cm near the center of the disk, where mu is greater than 0.6-0.7. This may indicate a nonuniform distribution of ammonia at layers at and above the visible cloud layers.

  6. Nonthermal cosmic neutrino background

    NASA Astrophysics Data System (ADS)

    Chen, Mu-Chun; Ratz, Michael; Trautner, Andreas

    2015-12-01

    We point out that, for Dirac neutrinos, in addition to the standard thermal cosmic neutrino background (C ν B ), there could also exist a nonthermal neutrino background with comparable number density. As the right-handed components are essentially decoupled from the thermal bath of standard model particles, relic neutrinos with a nonthermal distribution may exist until today. The relic density of the nonthermal (nt) background can be constrained by the usual observational bounds on the effective number of massless degrees of freedom Neff and can be as large as nν nt≲0.5 nγ. In particular, Neff can be larger than 3.046 in the absence of any exotic states. Nonthermal relic neutrinos constitute an irreducible contribution to the detection of the C ν B and, hence, may be discovered by future experiments such as PTOLEMY. We also present a scenario of chaotic inflation in which a nonthermal background can naturally be generated by inflationary preheating. The nonthermal relic neutrinos, thus, may constitute a novel window into the very early Universe.

  7. Entwurfskonzept einer Car2Car-Multiband-Dachantenne

    NASA Astrophysics Data System (ADS)

    Wang, Y.; Reit, M.; Mathis, W.

    2012-09-01

    Due to the vastly increasing use of wireless services in the car, such as WiFi, Car2Car and LTE, the requirements on bandwidth and radiation pattern of the roof antenna systems become more challenging. In this work, a design concept for multi-band roof antenna systems is presented. We aim to get a higher bandwidth and an almost circular radiation pattern on the horizontal plane. Moreover, the antenna length is considered in order to fulfill the requirements set by construction ECE-regulations (ECE, 2010). The applicability of the design concept is not limited to multi-band roof antennas, it can also be used for a general wideband antenna design. For illustration of this concept, a multi-band roof antenna with a bandwidth of 780 MHz to 5.9 GHz and a near circular radiation pattern with an average gain of G = 3 dBi (at 5.9 GHz) on the horizontal plane is designed. The simulation and measurement results are presented.

  8. Nonthermal 'WIMP miracle'

    SciTech Connect

    Acharya, Bobby Samir; Kane, Gordon; Watson, Scott; Kumar, Piyush

    2009-10-15

    Light scalar fields with only gravitational strength couplings are typically present in UV complete theories of physics beyond the standard model. In the early universe it is natural for these fields to dominate the energy density, and their subsequent decay - if prior to big bang nucleosynthesis - will typically yield some dark matter particles in their decay products. In this paper we make the observation that a Nonthermal 'WIMP Miracle' may result: that is, in the simplest solution to the cosmological moduli problem, nonthermally produced WIMPs can naturally account for the observed dark matter relic density.

  9. The normalised difference vegetation index obtained from agrometeorological standard radiation sensors: A comparison with ground-based multiband spectroradiometer measurements during the phenological development of an oat canopy.

    PubMed

    Wittich, Klaus-Peter; Kraft, Martin

    2008-01-01

    Following the methodology of K. F. Huemmrich and colleagues [Huemmrich et al. (1999) J Geophys Res 104:27,935-27,944], agrometeorological standard radiation sensors, i.e. two photosynthetically active radiation sensors and an albedometer, were used to measure the broadband visible and optical-infrared reflectance of an oat plot during its whole growth period. From these reflectance data - recorded as 15-min averages and pooled to daily means - the seasonal cycle of the normalised difference vegetation index (NDVI) was calculated. In addition, a ground-based multi-channel spectroradiometer was used as a reference to estimate narrowband "green" and "red" NDVIs at weekly intervals near noon. The narrowband "green" NDVI was shown to be consistent with the simultaneous broadband 15-min NDVI. This shows that the configuration of agrometeorological radiation sensors is suitable to adequately track phenological crop dynamics. PMID:17576603

  10. Nonthermal Supermassive Dark Matter

    NASA Technical Reports Server (NTRS)

    Chung, Daniel J. H.; Kolb, Edward W.; Riotto, Antonio

    1999-01-01

    We discuss several cosmological production mechanisms for nonthermal supermassive dark matter and argue that dark matter may he elementary particles of mass much greater than the weak scale. Searches for dark matter should ma be limited to weakly interacting particles with mass of the order of the weak scale, but should extend into the supermassive range as well.

  11. Non-thermal AGN models

    SciTech Connect

    Band, D.L.

    1986-12-01

    The infrared, optical and x-ray continua from radio quiet active galactic nuclei (AGN) are explained by a compact non-thermal source surrounding a thermal ultraviolet emitter, presumably the accretion disk around a supermassive black hole. The ultraviolet source is observed as the ''big blue bump.'' The flat (..cap alpha.. approx. = .7) hard x-ray spectrum results from the scattering of thermal ultraviolet photons by the flat, low energy end of an electron distribution ''broken'' by Compton losses; the infrared through soft x-ray continuum is the synchrotron radiation of the steep, high energy end of the electron distribution. Quantitative fits to specific AGN result in models which satisfy the variability constraints but require electron (re)acceleration throughout the source. 11 refs., 1 fig.

  12. Nonthermal Radio Emission and the HR Diagram

    NASA Technical Reports Server (NTRS)

    Gibson, D. M.

    1985-01-01

    Perhaps the most reliable indicator of non-radiative heating/momentum in a stellar atmosphere is the presence of nonthermal radio emission. To date, 77 normal stellar objects have been detected and identified as nonthermal sources. These stellar objects are tabulated herein. It is apparent that non-thermal radio emission is not ubiquitous across the HR diagram. This is clearly the case for the single stars; it is not as clear for the binaries unless the radio emission is associated with their late-type components. Choosing to make this association, the single stars and the late-type components are plotted together. The following picture emerges: (1) there are four locations on the HR diagram where non-thermal radio stars are found; (2) the peak incoherent 5 GHz luminosities show a suprisingly small range for stars within each class; (3) the fraction of stellar energy that escapes as radio emission can be estimated by comparing the integrated maximum radio luminosity to the bolometric luminosity; (4) there are no apparent differences in L sub R between binaries with two cool components, binaries with one hot and one cool component, and single stars for classes C and D; and (5) The late-type stars (classes B, C, and D) are located in parts of the HR diagram where there is reason to suspect that the surfaces of the stars are being braked with respect to their interiors.

  13. Multiband radar for homeland security

    NASA Astrophysics Data System (ADS)

    Tahim, Raghbir S.; Foshee, James; Chang, Kai

    2004-09-01

    Radar systems, which can operate in a variety of frequency bands, could provide significant flexibility in the operation of future Battle-space Management and Air Defense Systems (BMADS). Phased array antennas, which support high pulse rates and power, are well suited for surveillance, tracking and identifying the targets. These phased array antennas with the multiplicity of elements in phased array could provide accurate beam pointing, very rapid changes in beam location, and multiple beams, including algorithms for null steering for unwanted signals. No single radar band possesses characteristics that provide optimum performance. For example, L and S-bands are typically considered the best frequency ranges for acquisition and X-band is best for tracking. For many of the current phased array antennas the circuit components are narrow-band and therefore are not suitable for multi-band radar design. In addition, the cost, size, power dissipation, the weight, and, in general, the complexity has limited the development of multi-band phased array antenna systems. The system bandwidth of antenna array employing high loss phase shifters for beam steering also becomes limited due to the dispersion loss from the beam steering. As a result phased array radar design can result in a very large, complex, expensive, narrow band and less efficient system. This paper describes an alternative design approach in the design of wide-band phased array radar system based on multi-octave band antenna elements; and wide-band low loss phase shifters, switching circuits and T/R modules.

  14. Spectroscopy and nonthermal processes

    NASA Technical Reports Server (NTRS)

    Querci, Monique

    1987-01-01

    Stellar spectra are analyzed to determine nonthermal processes for cool stars. A shock wave crossing model is supported by a study of the behavior of absorption and emission spectra. The shock waves are attributed to atmospheric kinetics. Circumstellar spectral lines are studied for information about gaseous circumstellar layers. The description of stellar envelopes is carried on through circumstellar dust. Characteristic properties of polarization in the dust are described in the case of specific stars, emphasizing narrowband observations in Mira, semiregular, and supergiant stars. Finally, the direct approach to measuring the angular diameters of stars and mapping the distribution of circumstellar dust and gas by lunar occultation or interferometry is discussed, using two prototype stars, an M supergiant and a dusty carbon star.

  15. Non-thermal Plasma and Oxidative Stress

    NASA Astrophysics Data System (ADS)

    Toyokuni, Shinya

    2015-09-01

    Thermal plasmas and lasers have been used in medicine to cut and ablate tissues and for coagulation. Non-equilibrium atmospheric pressure plasma (NEAPP; non-thermal plasma) is a recently developed, non-thermal technique with possible biomedical applications. Although NEAPP reportedly generates reactive oxygen/nitrogen species, electrons, positive ions, and ultraviolet radiation, few research projects have been conducted to merge this technique with conventional free radical biology. Recently, Prof. Masaru Hori's group (Plasma Nanotechnology Research Center, Nagoya University) developed a NEAPP device with high electron density. Here electron spin resonance revealed hydroxyl radicals as a major product. To merge non-thermal plasma biology with the preexisting free radical biology, we evaluated lipid peroxidation and DNA modifications in various in vitro and ex vivo experiments. Conjugated dienes increased after exposure to linoleic and alfa-linolenic acids. An increase in 2-thiobarbituric acid-reactive substances was also increased after exposure to phosphatidylcholine, liposomes or liver homogenate. Direct exposure to rat liver in medium produced immunohistochemical evidence of 4-hydroxy-2-nonenal- and acrolein-modified proteins. Exposure to plasmid DNA induced dose-dependent single/double strand breaks and increased the amounts of 8-hydroxy-2'-deoxyguanosine and cyclobutane pyrimidine dimers. These results indicate that oxidative biomolecular damage by NEAPP is dose-dependent and thus can be controlled in a site-specific manner. Simultaneous oxidative and UV-specific DNA damage may be useful in cancer treatment. Other recent advancements in the related studies of non-thermal plasma in Nagoya University Graduate School of Medicine will also be discussed.

  16. Fast pulse nonthermal plasma reactor

    DOEpatents

    Rosocha, Louis A.

    2005-06-14

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

  17. Quantum structures for multiband photon detection

    NASA Astrophysics Data System (ADS)

    Perera, A. G. U.

    2005-09-01

    The work describes multiband photon detectors based on semiconductor micro- and nano-structures. The devices considered include quantum dot, homojunction, and heterojunction structures. In the quantum dot structures, transitions are from one state to another, while free carrier absorption and internal photoemission play the dominant role in homo or heterojunction detectors. Quantum Dots-in-a-Well (DWELL) detectors can tailor the response wavelength by varying the size of the well. A tunneling Quantum Dot Infrared Photodetector (T-QDIP) could operate at room temperature by blocking the dark current except in the case of resonance. Photoexcited carriers are selectively collected from InGaAs quantum dots by resonant tunneling, while the dark current is blocked by AlGaAs/InGaAs tunneling barriers placed in the structure. A two-color infrared detector with photoresponse peaks at ~6 and ~17 μm at room temperature will be discussed. A Homojunction or HEterojunction Interfacial Workfunction Internal Photoemission (HIWIP or HEIWIP) infrared detector, formed by a doped emitter layer, and an intrinsic layer acting as the barrier followed by another highly doped contact layer, can detect near infrared (NIR) photons due to interband transitions and mid/far infrared (MIR/FIR) radiation due to intraband transitions. The threshold wavelength of the interband response depends on the band gap of the barrier material, and the MIR/FIR response due to intraband transitions can be tailored by adjusting the band offset between the emitter and the barrier. GaAs/AlGaAs will provide NIR and MIR/FIR dual band response, and with GaN/AlGaN structures the detection capability can be extended into the ultraviolet region. These detectors are useful in numerous applications such as environmental monitoring, medical diagnosis, battlefield-imaging, space astronomy applications, mine detection, and remote-sensing.

  18. LARSPEC spectroradiometer-multiband radiometer data formats

    NASA Technical Reports Server (NTRS)

    Biehl, L. L.

    1982-01-01

    The data base software system, LARSPEC, is discussed and the data base format for agronomic, meteorological, spectroradiometer, and multiband radiometer data is described. In addition, the contents and formats of each record of data and the wavelength tables are listed and the codes used for some of the parameters are described.

  19. Hexagonal and Pentagonal Fractal Multiband Antennas

    NASA Technical Reports Server (NTRS)

    Tang, Philip W.; Wahid, Parveen

    2005-01-01

    Multiband dipole antennas based on hexagonal and pentagonal fractals have been analyzed by computational simulations and functionally demonstrated in experiments on prototypes. These antennas are capable of multiband or wide-band operation because they are subdivided into progressively smaller substructures that resonate at progressively higher frequencies by virtue of their smaller dimensions. The novelty of the present antennas lies in their specific hexagonal and pentagonal fractal configurations and the resonant frequencies associated with them. These antennas are potentially applicable to a variety of multiband and wide-band commercial wireless-communication products operating at different frequencies, including personal digital assistants, cellular telephones, pagers, satellite radios, Global Positioning System receivers, and products that combine two or more of the aforementioned functions. Perhaps the best-known prior multiband antenna based on fractal geometry is the Sierpinski triangle antenna (also known as the Sierpinski gasket), shown in the top part of the figure. In this antenna, the scale length at each iteration of the fractal is half the scale length of the preceding iteration, yielding successive resonant frequencies related by a ratio of about 2. The middle and bottom parts of the figure depict the first three iterations of the hexagonal and pentagonal fractals along with typical dipole-antenna configuration based on the second iteration. Successive resonant frequencies of the hexagonal fractal antenna have been found to be related by a ratio of about 3, and those of the pentagonal fractal antenna by a ratio of about 2.59.

  20. Development and validation of nonthermal and advanced thermal food safety intervention technologies

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Alternative nonthermal and thermal food safety interventions are gaining acceptance by the food processing industry and consumers. These technologies include high pressure processing, ultraviolet and pulsed light, ionizing radiation, pulsed and radiofrequency electric fields, cold atmospheric plasm...

  1. Multi-Band Miniaturized Patch Antennas for a Compact, Shielded Microwave Breast Imaging Array

    PubMed Central

    Aguilar, Suzette M.; Al-Joumayly, Mudar A.; Burfeindt, Matthew J.; Behdad, Nader; Hagness, Susan C.

    2014-01-01

    We present a comprehensive study of a class of multi-band miniaturized patch antennas designed for use in a 3D enclosed sensor array for microwave breast imaging. Miniaturization and multi-band operation are achieved by loading the antenna with non-radiating slots at strategic locations along the patch. This results in symmetric radiation patterns and similar radiation characteristics at all frequencies of operation. Prototypes were fabricated and tested in a biocompatible immersion medium. Excellent agreement was obtained between simulations and measurements. The trade-off between miniaturization and radiation efficiency within this class of patch antennas is explored via a numerical analysis of the effects of the location and number of slots, as well as the thickness and permittivity of the dielectric substrate, on the resonant frequencies and gain. Additionally, we compare 3D quantitative microwave breast imaging performance achieved with two different enclosed arrays of slot-loaded miniaturized patch antennas. Simulated array measurements were obtained for a 3D anatomically realistic numerical breast phantom. The reconstructed breast images generated from miniaturized patch array data suggest that, for the realistic noise power levels assumed in this study, the variations in gain observed across this class of multi-band patch antennas do not significantly impact the overall image quality. We conclude that these miniaturized antennas are promising candidates as compact array elements for shielded, multi-frequency microwave breast imaging systems. PMID:25392561

  2. Multi-Band Miniaturized Patch Antennas for a Compact, Shielded Microwave Breast Imaging Array.

    PubMed

    Aguilar, Suzette M; Al-Joumayly, Mudar A; Burfeindt, Matthew J; Behdad, Nader; Hagness, Susan C

    2013-12-18

    We present a comprehensive study of a class of multi-band miniaturized patch antennas designed for use in a 3D enclosed sensor array for microwave breast imaging. Miniaturization and multi-band operation are achieved by loading the antenna with non-radiating slots at strategic locations along the patch. This results in symmetric radiation patterns and similar radiation characteristics at all frequencies of operation. Prototypes were fabricated and tested in a biocompatible immersion medium. Excellent agreement was obtained between simulations and measurements. The trade-off between miniaturization and radiation efficiency within this class of patch antennas is explored via a numerical analysis of the effects of the location and number of slots, as well as the thickness and permittivity of the dielectric substrate, on the resonant frequencies and gain. Additionally, we compare 3D quantitative microwave breast imaging performance achieved with two different enclosed arrays of slot-loaded miniaturized patch antennas. Simulated array measurements were obtained for a 3D anatomically realistic numerical breast phantom. The reconstructed breast images generated from miniaturized patch array data suggest that, for the realistic noise power levels assumed in this study, the variations in gain observed across this class of multi-band patch antennas do not significantly impact the overall image quality. We conclude that these miniaturized antennas are promising candidates as compact array elements for shielded, multi-frequency microwave breast imaging systems. PMID:25392561

  3. Multiband Photonic Phased-Array Antenna

    NASA Technical Reports Server (NTRS)

    Tang, Suning

    2015-01-01

    A multiband phased-array antenna (PAA) can reduce the number of antennas on shipboard platforms while offering significantly improved performance. Crystal Research, Inc., has developed a multiband photonic antenna that is based on a high-speed, optical, true-time-delay beamformer. It is capable of simultaneously steering multiple independent radio frequency (RF) beams in less than 1,000 nanoseconds. This high steering speed is 3 orders of magnitude faster than any existing optical beamformer. Unlike other approaches, this technology uses a single controlling device per operation band, eliminating the need for massive optical switches, laser diodes, and fiber Bragg gratings. More importantly, only one beamformer is needed for all antenna elements.

  4. Multiband stereometamaterial-based polarization spectral filter

    NASA Astrophysics Data System (ADS)

    Shi, J. H.; Ma, H. F.; Jiang, W. X.; Cui, T. J.

    2012-07-01

    We propose a kind of stereometamaterial composed of periodic structures with twisted asymmetrical split-ring (ASR) resonators. The proposed stereometamaterial has intrinsic chirality and can be used as a multiband polarization spectral filter. Full-wave simulation and experimental results demonstrate that the stereometamaterial with the twist angle of φ=90∘ exhibits three ripple-free cross-polarization transmission peaks at normal incidence of plane waves. The cross-polarization transmission bands are centered at the maxima of circular dichroism, accompanied by pairs of pure circular birefringence points. In physics, the near-field electric and magnetic coupling of orthogonal ASR molecules in parallel planes contributes to the conversion of two orthogonal linear polarizations. The transmission of the proposed multiband polarization spectral filter can be engineered via the mutual twist angle and asymmetry of the ASRs and the thickness of the dielectric spacer layer and also be tuned via the angle of incidence.

  5. Multiband signal reconstruction for random equivalent sampling

    NASA Astrophysics Data System (ADS)

    Zhao, Y. J.; Liu, C. J.

    2014-10-01

    The random equivalent sampling (RES) is a sampling approach that can be applied to capture high speed repetitive signals with a sampling rate that is much lower than the Nyquist rate. However, the uneven random distribution of the time interval between the excitation pulse and the signal degrades the signal reconstruction performance. For sparse multiband signal sampling, the compressed sensing (CS) based signal reconstruction algorithm can tease out the band supports with overwhelming probability and reduce the impact of uneven random distribution in RES. In this paper, the mathematical model of RES behavior is constructed in the frequency domain. Based on the constructed mathematical model, the band supports of signal can be determined. Experimental results demonstrate that, for a signal with unknown sparse multiband, the proposed CS-based signal reconstruction algorithm is feasible, and the CS reconstruction algorithm outperforms the traditional RES signal reconstruction method.

  6. Multiband signal reconstruction for random equivalent sampling.

    PubMed

    Zhao, Y J; Liu, C J

    2014-10-01

    The random equivalent sampling (RES) is a sampling approach that can be applied to capture high speed repetitive signals with a sampling rate that is much lower than the Nyquist rate. However, the uneven random distribution of the time interval between the excitation pulse and the signal degrades the signal reconstruction performance. For sparse multiband signal sampling, the compressed sensing (CS) based signal reconstruction algorithm can tease out the band supports with overwhelming probability and reduce the impact of uneven random distribution in RES. In this paper, the mathematical model of RES behavior is constructed in the frequency domain. Based on the constructed mathematical model, the band supports of signal can be determined. Experimental results demonstrate that, for a signal with unknown sparse multiband, the proposed CS-based signal reconstruction algorithm is feasible, and the CS reconstruction algorithm outperforms the traditional RES signal reconstruction method. PMID:25362458

  7. Non-contact multiband method for emissivity measurement

    NASA Astrophysics Data System (ADS)

    Mazikowski, Adam; Chrzanowski, Krzysztof

    2003-04-01

    During the last decade an increasing interest in passive multiband systems for temperature measurement was noted and quite a few such systems have been developed. However, recent studies showed that multiband systems are capable of producing accurate results of non-contact temperature measurement only in limited number of applications and that multiband systems will not become a real rival for single band systems in temperature measurement applications. Available literature about passive multiband systems concentrated exclusively on the problem of temperature measurements with these systems in situation when these systems can be used for non-contact emissivity measurements too. A model of a passive multiband system for non-contact emissivity measurement has been developed in this paper. Simulations carried out using this model showed that it is possible to achieve reasonable accuracy of emissivity measurements with passive multiband systems and these systems can be considered as an attractive solution for emissivity measurements in industrial conditions.

  8. Periodograms for Multiband Astronomical Time Series

    NASA Astrophysics Data System (ADS)

    VanderPlas, Jacob T.; Iv´, Željko

    2015-10-01

    This paper introduces the multiband periodogram, a general extension of the well-known Lomb-Scargle approach for detecting periodic signals in time-domain data. In addition to advantages of the Lomb-Scargle method such as treatment of non-uniform sampling and heteroscedastic errors, the multiband periodogram significantly improves period finding for randomly sampled multiband light curves (e.g., Pan-STARRS, DES, and LSST). The light curves in each band are modeled as arbitrary truncated Fourier series, with the period and phase shared across all bands. The key aspect is the use of Tikhonov regularization which drives most of the variability into the so-called base model common to all bands, while fits for individual bands describe residuals relative to the base model and typically require lower-order Fourier series. This decrease in the effective model complexity is the main reason for improved performance. After a pedagogical development of the formalism of least-squares spectral analysis, which motivates the essential features of the multiband model, we use simulated light curves and randomly subsampled SDSS Stripe 82 data to demonstrate the superiority of this method compared to other methods from the literature and find that this method will be able to efficiently determine the correct period in the majority of LSST’s bright RR Lyrae stars with as little as six months of LSST data, a vast improvement over the years of data reported to be required by previous studies. A Python implementation of this method, along with code to fully reproduce the results reported here, is available on GitHub.

  9. Passband switchable microwave photonic multiband filter.

    PubMed

    Ge, Jia; Fok, Mable P

    2015-01-01

    A reconfigurable microwave photonic (MWP) multiband filter with selectable and switchable passbands is proposed and experimentally demonstrated, with a maximum of 12 simultaneous passbands evenly distributed from 0 to 10 GHz. The scheme is based on the generation of tunable optical comb lines using a two-stage Lyot loop filter, such that various filter tap spacings and spectral combinations are obtained for the configuration of the MWP filter. Through polarization state adjustment inside the Lyot loop filter, an optical frequency comb with 12 different comb spacings is achieved, which corresponds to a MWP filter with 12 selectable passbands. Center frequencies of the filter passbands are switchable, while the number of simultaneous passbands is tunable from 1 to 12. Furthermore, the MWP multiband filter can either work as an all-block, single-band or multiband filter with various passband combinations, which provide exceptional operation flexibility. All the passbands have over 30 dB sidelobe suppression and 3-dB bandwidth of 200 MHz, providing good filter selectivity. PMID:26521693

  10. Passband switchable microwave photonic multiband filter

    NASA Astrophysics Data System (ADS)

    Ge, Jia; Fok, Mable P.

    2015-11-01

    A reconfigurable microwave photonic (MWP) multiband filter with selectable and switchable passbands is proposed and experimentally demonstrated, with a maximum of 12 simultaneous passbands evenly distributed from 0 to 10 GHz. The scheme is based on the generation of tunable optical comb lines using a two-stage Lyot loop filter, such that various filter tap spacings and spectral combinations are obtained for the configuration of the MWP filter. Through polarization state adjustment inside the Lyot loop filter, an optical frequency comb with 12 different comb spacings is achieved, which corresponds to a MWP filter with 12 selectable passbands. Center frequencies of the filter passbands are switchable, while the number of simultaneous passbands is tunable from 1 to 12. Furthermore, the MWP multiband filter can either work as an all-block, single-band or multiband filter with various passband combinations, which provide exceptional operation flexibility. All the passbands have over 30 dB sidelobe suppression and 3-dB bandwidth of 200 MHz, providing good filter selectivity.

  11. Passband switchable microwave photonic multiband filter

    PubMed Central

    Ge, Jia; Fok, Mable P.

    2015-01-01

    A reconfigurable microwave photonic (MWP) multiband filter with selectable and switchable passbands is proposed and experimentally demonstrated, with a maximum of 12 simultaneous passbands evenly distributed from 0 to 10 GHz. The scheme is based on the generation of tunable optical comb lines using a two-stage Lyot loop filter, such that various filter tap spacings and spectral combinations are obtained for the configuration of the MWP filter. Through polarization state adjustment inside the Lyot loop filter, an optical frequency comb with 12 different comb spacings is achieved, which corresponds to a MWP filter with 12 selectable passbands. Center frequencies of the filter passbands are switchable, while the number of simultaneous passbands is tunable from 1 to 12. Furthermore, the MWP multiband filter can either work as an all-block, single-band or multiband filter with various passband combinations, which provide exceptional operation flexibility. All the passbands have over 30 dB sidelobe suppression and 3-dB bandwidth of 200 MHz, providing good filter selectivity. PMID:26521693

  12. Periodograms for multiband astronomical time series

    NASA Astrophysics Data System (ADS)

    Ivezic, Z.; VanderPlas, J. T.

    2016-05-01

    We summarize the multiband periodogram, a general extension of the well-known Lomb-Scargle approach for detecting periodic signals in time- domain data developed by VanderPlas & Ivezic (2015). A Python implementation of this method is available on GitHub. The multiband periodogram significantly improves period finding for randomly sampled multiband light curves (e.g., Pan-STARRS, DES, and LSST), and can treat non-uniform sampling and heteroscedastic errors. The light curves in each band are modeled as arbitrary truncated Fourier series, with the period and phase shared across all bands. The key aspect is the use of Tikhonov regularization which drives most of the variability into the so-called base model common to all bands, while fits for individual bands describe residuals relative to the base model and typically require lower-order Fourier series. We use simulated light curves and randomly subsampled SDSS Stripe 82 data to demonstrate the superiority of this method compared to other methods from the literature, and find that this method will be able to efficiently determine the correct period in the majority of LSST's bright RR Lyrae stars with as little as six months of LSST data.

  13. Tomographic diagnostics of nonthermal plasmas

    NASA Astrophysics Data System (ADS)

    Denisova, Natalia

    2009-10-01

    In the previous work [1], we discussed a ``technology'' of tomographic method and relations between the tomographic diagnostics in thermal (equilibrium) and nonthermal (nonequilibrium) plasma sources. The conclusion has been made that tomographic reconstruction in thermal plasma sources is the standard procedure at present, which can provide much useful information on the plasma structure and its evolution in time, while the tomographic reconstruction of nonthermal plasma has a great potential at making a contribution to understanding the fundamental problem of substance behavior in strongly nonequilibrium conditions. Using medical terminology, one could say, that tomographic diagnostics of the equilibrium plasma sources studies their ``anatomic'' structure, while reconstruction of the nonequilibrium plasma is similar to the ``physiological'' examination: it is directed to study the physical mechanisms and processes. The present work is focused on nonthermal plasma research. The tomographic diagnostics is directed to study spatial structures formed in the gas discharge plasmas under the influence of electrical and gravitational fields. The ways of plasma ``self-organization'' in changing and extreme conditions are analyzed. The analysis has been made using some examples from our practical tomographic diagnostics of nonthermal plasma sources, such as low-pressure capacitive and inductive discharges. [0pt] [1] Denisova N. Plasma diagnostics using computed tomography method // IEEE Trans. Plasma Sci. 2009 37 4 502.

  14. Nonthermal processing technologies for food

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Looking forward into the future of food science/technology/engineering, in the emerging area of nonthermal processing of foods, is definitely an adventure. It is open-ended and full of uncertainties. Lessons learned from the past should always serve as a good basis for envisioning the future of this...

  15. Integrated nonthermal treatment system study

    SciTech Connect

    Biagi, C.; Bahar, D.; Teheranian, B.; Vetromile, J.; Quapp, W.J.; Bechtold, T.; Brown, B.; Schwinkendorf, W.; Swartz, G.

    1997-01-01

    This report presents the results of a study of nonthermal treatment technologies. The study consisted of a systematic assessment of five nonthermal treatment alternatives. The treatment alternatives consist of widely varying technologies for safely destroying the hazardous organic components, reducing the volume, and preparing for final disposal of the contact-handled mixed low-level waste (MLLW) currently stored in the US Department of Energy complex. The alternatives considered were innovative nonthermal treatments for organic liquids and sludges, process residue, soil and debris. Vacuum desorption or various washing approaches are considered for treatment of soil, residue and debris. Organic destruction methods include mediated electrochemical oxidation, catalytic wet oxidation, and acid digestion. Other methods studied included stabilization technologies and mercury separation of treatment residues. This study is a companion to the integrated thermal treatment study which examined 19 alternatives for thermal treatment of MLLW waste. The quantities and physical and chemical compositions of the input waste are based on the inventory database developed by the US Department of Energy. The Integrated Nonthermal Treatment Systems (INTS) systems were evaluated using the same waste input (2,927 pounds per hour) as the Integrated Thermal Treatment Systems (ITTS). 48 refs., 68 figs., 37 tabs.

  16. Vitamin D synthesis measured with a multiband filter radiometer in Río Gallegos, Argentina

    NASA Astrophysics Data System (ADS)

    Orte, Facundo; Wolfram, Elian; Salvador, Jacobo; D'Elia, Raúl; Bulnes, Daniela; Leme, N. Paes; Quel, Eduardo

    2013-05-01

    Vitamin D plays an important role in human health. Vitamin D production from the sun is affected by UVB solar radiation. This paper presents a simple method for retrieving vitamin D-weighted UV by using a multiband filter radiometer GUV-541 installed at the Atmospheric Observatory of Southern Patagonia (OAPA) (51 ° 33' S, 69° 19' W), Río Gallegos. The methodology used combines irradiance measurements from a multiband filter radiometer with spectral irradiance modeled by the SOS radiative transfer code (developed by Lille University of Science and Technology (USTL)). The spectrum modeled is weighted with vitamin D action spectra published by the International Commission on Illumination (CIE), which describes the relative effectiveness of different wavelengths in the generation of this particular biological response. This method is validated using the vitamin D-weighted UV derived from a Brewer MKIII spectrophotometer (SN 124) belonging to the National Institute for Spatial Research (INPE), Brazil, which is able to measure solar spectra between 290 and 325nm. The method presents a good correlation between the two independent instruments. This procedure increases the instrumental capabilities of the multiband filter radiometer. Moreover, it evaluates the annual variation of vitamin D-weighted UV doses from exposure to ultraviolet radiation. These values are likely to be lower than suitable levels of vitamin D during winter and part of spring and autumn at these latitudes.

  17. A thermal/nonthermal approach to solar flares

    NASA Technical Reports Server (NTRS)

    Benka, Stephen G.

    1991-01-01

    An approach for modeling solar flare high-energy emissions is developed in which both thermal and nonthermal particles coexist and contribute to the radiation. The thermal/nonthermal distribution function is interpreted physically by postulating the existence of DC sheets in the flare region. The currents then provide both primary plasma heating through Joule dissipation, and runaway electron acceleration. The physics of runaway acceleration is discussed. Several methods are presented for obtaining approximations to the thermal/nonthermal distribution function, both within the current sheets and outside of them. Theoretical hard x ray spectra are calculated, allowing for thermal bremsstrahlung from the heated plasma electrons impinging on the chromosphere. A simple model for hard x ray images of two-ribbon flares is presented. Theoretical microwave gyrosynchrotron spectra are calculated and analyzed, uncovering important new effects caused by the interplay of thermal and nonthermal particles. The theoretical spectra are compared with observed high resolution spectra of solar flares, and excellent agreement is found, in both hard x rays and microwaves. The future detailed application of this approach to solar flares is discussed, as are possible refinements to this theory.

  18. Multibanded parametric processing (Invited Paper)

    NASA Astrophysics Data System (ADS)

    Radic, Stojan

    2005-05-01

    The ability to coherently generate and process arbitrary waveforms over wide frequency range is recognized as the core technology required for spectral dominance. Low observable (LO) radar technologies are expected to radically change the nature of tracking, acquisition and targeting in future combat environments. While passive LO designs drastically reduce backscatter radar cross section (RCS), they inherently compromise the performance of the airframe: a minimal RCS solution is not necessarily the optimal aerodynamic geometry. Recent demonstrations unify both LO and wide flight envelope. However, the approach dictates very high per-unit cost and is unlikely to lead to mass production seen in the past. In contrast, active LO techniques do not compromise aerodynamic properties, while still drastically reducing RCS. Unfortunately, active LO is expected to proliferate in the near term: it is cost-effective and can be used to qualitatively improve capability of the existing air forces by retrofitting not only the manned fleet, but also the existing missile ordnance. Airframes in service are simply upgraded by portable (100kg or less) units reducing the RCS section by more than two orders of magnitude. Unlike passive LO that can be countered by receiver spatial diversity, active LO reduces both backscattered and refracted radiation, requiring spectral, rather than spatially diverse countermeasures.

  19. Evaluation of multiband photography for rock discrimination

    NASA Technical Reports Server (NTRS)

    Raines, G. L.

    1974-01-01

    An evaluation is presented of the multiband photography concept that tonal differences between rock formations on aerial photography can be improved through the selection of the appropriate bands. The concept involves: (1) acquiring band reference data for the rocks being considered; (2) selecting the best combination of bands to discriminate the rocks using these reference data; (3) acquiring aerial photography using these selected bands; and (4) extracting the desired geologic information in an optimum manner. The test site geology and rock reflectance are discussed in detail. The evaluation found that the differences in contrast ratios are not statistically significant, and the spectral information in different bands is not advantageous.

  20. MIPS - The Multiband Imaging Photometer for SIRTF

    NASA Technical Reports Server (NTRS)

    Rieke, G. H.; Lada, C.; Lebofsky, M.; Low, F.; Strittmatter, P.; Young, E.; Beichman, C.; Gautier, T. N.; Mould, J.; Werner, M.

    1986-01-01

    The Multiband Imaging Photometer System (MIPS) for SIRTF is to be designed to reach as closely as possible the fundamental sensitivity and angular resolution limits for SIRTF over the 3 to 700 microns spectral region. It will use high performance photoconductive detectors from 3 to 200 microns with integrating JFET amplifiers. From 200 to 700 microns, the MIPS will use a bolometer cooled by an adiabatic demagnetization refrigerator. Over much of its operating range, the MIPS will make possible observations at and beyond the conventional Rayleigh diffraction limit of angular resolution.

  1. Development of a Multiband Passive Scanning Imager

    NASA Astrophysics Data System (ADS)

    Tong, Jinchao; Huang, Zhingming; Hou, Yun; Zhang, Leibo; Zhou, Wei; Huang, Jingguo; Chu, Junhao

    2013-04-01

    A passive scanning imaging system that can operate at multiband spectra covering infrared, THz, and MMW regions has been developed. A high-quality optical system, which consists of a scanning swing planar mirror and a concave mirror, is used to be compatible in different frequency ranges. An elliptical aperture is opened at the center of the swing mirror to allow the focused light to pass through. Four types of detectors that contain two homemade bolometric detectors are used to distinguish images that range from infrared to millimeter waves. Our results demonstrate that the reflection-type imaging system performs well and exhibits compatibility to operate at different frequencies.

  2. Thermal and Nonthermal Electron-ion Bremsstrahlung Spectrum from High-Temperature Plasmas

    NASA Technical Reports Server (NTRS)

    Jung, Young-Dae

    1994-01-01

    Electron-ion bremsstrahlung radiation from high-temperature plasmas is investigated. The first- and second-order Coulomb corrections in the nonrelativistic bremsstrahlung radiation power are obtained by the Elwert-Sommerfeld factor. In this paper, two cases of the electron distributions, the thermal and nonthermal power-law distributions, are considered. The inclusion of Coulomb corrections is necessary in deducing correctly the electron distribution function from radiation data. These results provide the correct information of electron distributions in high-temperature plasmas, such as in inertial confinement fusion plasmas and in the astrophysical hot thermal and nonthermal x-ray sources.

  3. Nonthermal dark matter in mirage mediation

    SciTech Connect

    Nagai, Minoru; Nakayama, Kazunori

    2007-12-15

    In mirage-mediation models there exists a modulus field whose mass is O(1000) TeV and its late decay may significantly change the standard thermal relic scenario of the dark matter. We study nonthermal production of the dark matter directly from the modulus decay, and find that for some parameter regions nonthermally produced neutralinos can become the dark matter.

  4. Giant paramagnetic Meissner effect in multiband superconductors.

    PubMed

    da Silva, R M; Milošević, M V; Shanenko, A A; Peeters, F M; Aguiar, J Albino

    2015-01-01

    Superconductors, ideally diamagnetic when in the Meissner state, can also exhibit paramagnetic behavior due to trapped magnetic flux. In the absence of pinning such paramagnetic response is weak, and ceases with increasing sample thickness. Here we show that in multiband superconductors paramagnetic response can be observed even in slab geometries, and can be far larger than any previous estimate - even multiply larger than the diamagnetic Meissner response for the same applied magnetic field. We link the appearance of this giant paramagnetic response to the broad crossover between conventional Type-I and Type-II superconductors, where Abrikosov vortices interact non-monotonically and multibody effects become important, causing unique flux configurations and their locking in the presence of surfaces. PMID:26244936

  5. Giant paramagnetic Meissner effect in multiband superconductors

    PubMed Central

    da Silva, R. M.; Milošević, M. V.; Shanenko, A. A.; Peeters, F. M.; Aguiar, J. Albino

    2015-01-01

    Superconductors, ideally diamagnetic when in the Meissner state, can also exhibit paramagnetic behavior due to trapped magnetic flux. In the absence of pinning such paramagnetic response is weak, and ceases with increasing sample thickness. Here we show that in multiband superconductors paramagnetic response can be observed even in slab geometries, and can be far larger than any previous estimate - even multiply larger than the diamagnetic Meissner response for the same applied magnetic field. We link the appearance of this giant paramagnetic response to the broad crossover between conventional Type-I and Type-II superconductors, where Abrikosov vortices interact non-monotonically and multibody effects become important, causing unique flux configurations and their locking in the presence of surfaces. PMID:26244936

  6. Giant paramagnetic Meissner effect in multiband superconductors

    NASA Astrophysics Data System (ADS)

    da Silva, R. M.; Milošević, M. V.; Shanenko, A. A.; Peeters, F. M.; Aguiar, J. Albino

    2015-08-01

    Superconductors, ideally diamagnetic when in the Meissner state, can also exhibit paramagnetic behavior due to trapped magnetic flux. In the absence of pinning such paramagnetic response is weak, and ceases with increasing sample thickness. Here we show that in multiband superconductors paramagnetic response can be observed even in slab geometries, and can be far larger than any previous estimate - even multiply larger than the diamagnetic Meissner response for the same applied magnetic field. We link the appearance of this giant paramagnetic response to the broad crossover between conventional Type-I and Type-II superconductors, where Abrikosov vortices interact non-monotonically and multibody effects become important, causing unique flux configurations and their locking in the presence of surfaces.

  7. Time reversal acoustic communication for multiband transmission.

    PubMed

    Song, Aijun; Badiey, Mohsen

    2012-04-01

    In this letter, multiband acoustic communication is proposed to access a relatively wide frequency band. The entire frequency band is divided into multiple separated sub-bands, each of which is several kilohertz in width. Time reversal decision feedback equalizers are used to compensate for inter-symbol interference at each sub-band. The communication scheme was demonstrated in a shallow water acoustic experiment conducted in Kauai, Hawaii during the summer of 2011. Using quadrature phase-shift keying signaling at four sub-bands over the frequency band of 10-32 kHz, a data rate of 32 k bits/s was achieved over a 3 km communication range. PMID:22502482

  8. An evaluation of multiband photography for rock discrimination

    NASA Technical Reports Server (NTRS)

    Raines, G. L.; Lee, K.

    1974-01-01

    The ability of multiband photography to discriminate sedimentary rocks is investigated. Measurements showed that there is a large natural variation in the band reflectance of rock formations and that the differences in the contrast ratios for different Wratten filters is small, making it statistically impossible to select a set of best bands from in situ reflectance measurements. It is concluded that the designed multiband photography concept is not a practical method for improving sedimentary-rock discrimination capabilities.

  9. Compact multi-band (VIS/IR) zoom imager for high resolution long range surveillance

    NASA Astrophysics Data System (ADS)

    Bodkin, Andrew; Sheinis, Andrew; McCann, James

    2005-05-01

    The objective of this project is to seamlessly integrate multiple spectral-band focal plane detector arrays into a single multi-band imaging sensor. The resulting product can be applied to a telescope or a microscope, as simply as changing a lens on a camera. The video stream output provides a set of co-registered digital images from a multiple of spectral bands spanning the Visible, NIR, MWIR and LWIR radiation regions (.4um to 14um). These images have a format that is suitable both for direct observation by a human operator and as a data feed for Automated Target Recognition (ATR) algorithms.

  10. Modeling nonthermal emission from stellar bow shocks

    NASA Astrophysics Data System (ADS)

    Pereira, V.; López-Santiago, J.; Miceli, M.; Bonito, R.; de Castro, E.

    2016-04-01

    Context. Runaway O- and early B-type stars passing through the interstellar medium at supersonic velocities and characterized by strong stellar winds may produce bow shocks that can serve as particle acceleration sites. Previous theoretical models predict the production of high-energy photons by nonthermal radiative processes, but their efficiency is still debated. Aims: We aim to test and explain the possibility of emission from the bow shocks formed by runaway stars traveling through the interstellar medium by using previous theoretical models. Methods: We applied our model to AE Aurigae, the first reported star with an X-ray detected bow shock, to BD+43 3654, in which the observations failed in detecting high-energy emission, and to the transition phase of a supergiant star in the late stages of its life. Results: From our analysis, we confirm that the X-ray emission from the bow shock produced by AE Aurigae can be explained by inverse Compton processes involving the infrared photons of the heated dust. We also predict low high-energy flux emission from the bow shock produced by BD+43 3654, and the possibility of high-energy emission from the bow shock formed by a supergiant star during the transition phase from blue to red supergiant. Conclusions: Bow shocks formed by different types of runaway stars are revealed as a new possible source of high-energy photons in our neighborhood.

  11. Multiband CMOS sensor simplify FPA design

    NASA Astrophysics Data System (ADS)

    Wang, Weng Lyang B.; Ling, Jer

    2015-10-01

    Push broom multi-band Focal Plane Array (FPA) design needs to consider optics, image sensor, electronic, mechanic as well as thermal. Conventional FPA use two or several CCD device as an image sensor. The CCD image sensor requires several high speed, high voltage and high current clock drivers as well as analog video processors to support their operation. Signal needs to digitize using external sample / hold and digitized circuit. These support circuits are bulky, consume a lot of power, must be shielded and placed in close to the CCD to minimize the introduction of unwanted noise. The CCD also needs to consider how to dissipate power. The end result is a very complicated FPA and hard to make due to more weighs and draws more power requiring complex heat transfer mechanisms. In this paper, we integrate microelectronic technology and multi-layer soft / hard Printed Circuit Board (PCB) technology to design electronic portion. Since its simplicity and integration, the optics, mechanic, structure and thermal design will become very simple. The whole FPA assembly and dis-assembly reduced to a few days. A multi-band CMOS Sensor (dedicated as C468) was used for this design. The CMOS Sensor, allow for the incorporation of clock drivers, timing generators, signal processing and digitization onto the same Integrated Circuit (IC) as the image sensor arrays. This keeps noise to a minimum while providing high functionality at reasonable power levels. The C468 is a first Multiple System-On-Chip (MSOC) IC. This device used our proprietary wafer butting technology and MSOC technology to combine five long sensor arrays into a size of 120 mm x 23.2 mm and 155 mm x 60 mm for chip and package, respectively. The device composed of one Panchromatic (PAN) and four different Multi- Spectral (MS) sensors. Due to its integration on the electronic design, a lot of room is clear for the thermal design. The optical and mechanical design is become very straight forward. The flight model FPA

  12. MIPS - The Multiband Imaging Photometer for SIRTF. [Multiband Imaging Photometer for SIRTF

    NASA Technical Reports Server (NTRS)

    Rieke, G. H.; Lada, C.; Lebofsky, M.; Low, F.; Strittmatter, P.; Young, E.; Arens, J.; Beichman, C.; Gautier, T. N.; Werner, M.

    1986-01-01

    The Multiband Imaging Photometer for SIRTF (MIPS) is to be designed to reach as closely as possible the fundamental sensitivity and angular resolution limits for SIRTF over the 3 to 700 micron spectral region. It will use high performance photoconductive detectors from 3 to 200 micron with integrating JFET amplifiers. From 200 to 700 microns, the MIPS will use a bolometer cooled by an adiabatic demagnetization refrigerator. Over much of its operating range, the MIPS will make possible observations at and beyond the conventional Rayleigh diffraction limit of angular resolution.

  13. Design of a multiband terahertz perfect absorber

    NASA Astrophysics Data System (ADS)

    Dan, Hu; Hong-yan, Wang; Zhen-jie, Tang; Xi-wei, Zhang; Lin, Ju; Hua-ying, Wang

    2016-03-01

    A thin-flexible multiband terahertz metamaterial absorber (MA) has been investigated. Each unit cell of the MA consists of a simple metal structure, which includes the top metal resonator ring and the bottom metallic ground plane, separated by a thin-flexible dielectric spacer. Finite-difference time domain simulation indicates that this MA can achieve over 99% absorption at frequencies of 1.50 THz, 3.33 THz, and 5.40 THz by properly assembling the sandwiched structure. However, because of its asymmetric structure, the MA is polarization-sensitive and can tune the absorptivity of the second absorption peak by changing the incident polarization angle. The effect of the error of the structural parameters on the absorption efficiency is also carefully analyzed in detail to guide the fabrication. Moreover, the proposed MA exhibits high refractive-index sensing sensitivity, which has potential applications in multi-wavelength sensing in the terahertz region. Project supported by the National Natural Science Foundation of China (Grant No. 11504006), the Key Scientific Research Project of Higher Education of Henan Province, China (Grant No. 15A140002), and the Science and Technology Planning Project of Henan Province, China (Grant No. 142300410366).

  14. Non-thermal radio emission from Saturn

    NASA Technical Reports Server (NTRS)

    Warwick, J. W.

    1978-01-01

    Direct, strong evidence for non-thermal radio emission from Saturn exists in the hectometric data observed by Imp 6. The planet has been tentatively identified as a decametric source, but the most sensitive and most recent data fail to confirm this. At metric or decimetric wavelengths Saturn has no non-thermal emission like Jupiter's synchrotron sources. Finally, a comparative study of Earth and Jupiter radio emissions suggests lightning discharges.

  15. Nonthermal X-ray Microflares

    NASA Astrophysics Data System (ADS)

    Christe, S.; Rauscher, E.; Krucker, S.; Lin, R. P.

    2004-12-01

    The Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) provides unique sensitivity in the 3-15 keV energy range, with an effective area ˜100 times larger than similar past instruments. Along with its high spectral resolution (1 keV) RHESSI is uniquely suited to study small events. Microflares have been observed by Benz & Grigis (2002) and Krucker et al. (2002) to have anomalously steep spectra ( spectral index between -5 and -8) extending down to ˜ 7 keV. Thermal emission is found to dominate below ˜ 7 keV. In many other respects, microflares show properties similar to larger flares. We present single event studies of different types of x-ray microflares. RHESSI observations during quiet times (04-May 10-14; GOES level low B class) reveal a set 5 microflares (>=A Class). These microflares show power law spectra (spectral index of ˜4-8) with little or no thermal emission in the 3- ˜7 keV energy range above the nonthermal part of the spectrum. Other microflares in the same GOES class range, however, have been found which show extremely hard spectra with emission up to 50 keV (power law index ˜2). At lower energies, emission is dominated by a hot thermal component (20 MK). This work was supported by NASA contract NAS5-98033.

  16. Optically addressed multiband photodetector for infrared imaging applications

    NASA Astrophysics Data System (ADS)

    Cellek, O. O.; Zhang, Y.-H.

    2012-01-01

    Multiband infrared focal plane arrays (FPAs) with small pixel pitch have increased device processing complexity since they often need more than two terminals per pixel for readouts. Simpler FPAs are enabled by our newly demonstrated optically-addressed two-terminal multiband photodetector architecture. For long-wavelength infrared (LWIR) and midwavelength infrared (MWIR) imaging applications, the use of quantum well infrared photodetectors (QWIP) has been investigated. The results show that the utilization of unipolar QWIPs with bipolar near infrared (NIR) devices is feasible with this new optical-addressing scheme. Potential device performance is analyzed with an equivalent AC circuit model. Proposed design maximizes fill factor and enables small pixel-pitch FPA with single indium-bump per pixel for NIR/MWIR/LWIR multiband detection capability.

  17. Phenomenology of passive multi-band submillimeter-wave imagery

    NASA Astrophysics Data System (ADS)

    Enestam, Sissi; Kajatkari, Perttu; Kivimäki, Olli; Leivo, Mikko M.; Rautiainen, Anssi; Tamminen, Aleksi A.; Luukanen, Arttu R.

    2016-05-01

    In 2015, Asqella Oy commercialized a passive multi-band submillimeter-wave camera system intended for use in walk-by personnel security screening applications. In this paper we study the imagery acquired with the prototype of the ARGON passive multi-band submm-wave video camera. To challenge the system and test its limits, imagery has been obtained in various environments with varying background surface temperatures, with people of different body types, with different clothing materials and numbers of layers of clothing and with objects of different materials. In addition to the phenomenological study, we discuss the detection statistics of the system, evaluated by running blind trials with human operators. While significant improvements have been made particularly in the software side since the beginning of the testing, the obtained imagery enables a comprehensive evaluation of the capabilities and challenges of the multiband submillimeter-wave imaging system.

  18. Functional multi-band THz meta-foils

    PubMed Central

    Wu, Jianfeng; Moser, Herbert O.; Xu, Su; Jian, Linke; Banas, Agnieszka; Banas, Krzysztof; Chen, Hongsheng; Bettiol, Andrew A.; Breese, Mark B. H.

    2013-01-01

    In this paper, we present the first experimental demonstration of double- and triple-band negative refraction index meta-foils in the terahertz (THz) region. Multi-band meta-foils constructed by multi-cell S-string resonators in a single structure exhibit simultaneously negative permittivity and negative permeability responses at multiple frequencies. The phenomena are confirmed by numerical simulations and Fourier transform infrared spectroscopy measurements. The flexible, freestanding multi-band meta-foils provide a promising candidate for the development of multi-frequency THz materials and devices. PMID:24346309

  19. Combining hydrodynamic modeling with nonthermal test particle tracking to improve flare simulations

    NASA Astrophysics Data System (ADS)

    Winter, Henry Degraffenried, III

    Solar flares remain a subject of intense study in the solar physics community. These huge releases of energy on the Sun have direct consequences for humans on Earth and in space. The processes that impart tremendous amounts of energy are not well understood. In order to test theoretical models of flare formation and evolution, state of the art, numerical codes must be created that can accurately simulate the wide range of electromagnetic radiation emitted by flares. A direct comparison of simulated radiation to increasingly detailed observations will allow scientists to test the validity of theoretical models. To accomplish this task, numerical codes were developed that can simulate both the thermal and nonthermal components of a flaring plasma, their interactions, and their emissions. The HYLOOP code combines a hydrodynamic equation solver with a nonthermal particle tracking code in order to simulate the thermal and nonthermal aspects of a flare. A solar flare was simulated using this new code with a static atmosphere and with a dynamic atmosphere, to illustrate the importance of considering hydrodynamic effects on nonthermal beam evolution. The importance of density gradients in the evolution of nonthermal electron beams was investigated by studying their effects in isolation. The importance of the initial pitch-angle cosine distribution to flare dynamics was investigated. Emission in XRT filters were calculated and analyzed to see if there were soft X-ray signatures that could give clues to the nonthermal particle distributions. Finally the HXR source motions that appeared in the simulations were compared to real observations of this phenomena.

  20. Analysis on the electromagnetic scattering properties of crops at multi-band

    NASA Astrophysics Data System (ADS)

    Wu, Tao; Wu, Zhensen; Liu, Xiaoyi

    2014-12-01

    The vector radiative transfer (VRT) theory for active microwave remote sensing and Rayleigh-Gans approximation (GRG) are applied in the study, and an iterative algorithm is used to solve the RT equations, thus we obtain the zeroorder and first-order equation for numerical results. The Michigan Microwave Canopy Scattering (MIMICS) model is simplified to adapt to the crop model, by analyzing body-surface bistatic scattering and backscattering properties between a layer of soybean or wheat consisting of stems and leaves and different underlying soil surface at multi-band (i.e. P, L, S, X, Ku-band), we obtain microwave scattering mechanisms of crop components and the effect of underlying ground on total crop scattering. Stem and leaf are regard as a needle and a circular disk, respectively. The final results are compared with some literature data to verify our calculating method, numerical results show multi-band crop microwave scattering properties differ from scattering angle, azimuth angle and moisture of vegetation and soil, which offer the part needed information for the design of future bistatic radar systems for crop sensing applications.

  1. Multiband photometry of PSNJ14102342-4318437 with OAUNI

    NASA Astrophysics Data System (ADS)

    Pereyra, A.; Cori, W.; Ricra, J.; Zevallos, M.; Tello, J.

    2016-01-01

    We report multiband photometry of Type Ib SN PSNJ14102342-4318437 (ATel #8415, ATel #8434, ATel #8437, ATel #8504) on 2016-01-10 (UT) gathered with the OAUNI 51cm telescope (Pereyra et al. 2015; arXiv:1512.03104) at Huancayo Observatory, Peru.

  2. Multi-Band Polarimetry of Lunar Regolith Materials in Laboratory

    NASA Astrophysics Data System (ADS)

    Kim, I. H.; Jeong, M. S.; Sim, C. K.; Baek, K. H.; Kim, S. S.

    2015-11-01

    To understand the polarization characteristics of the lunar regolith, we have carried out multi-band (U, B, V, and R) polarimetric measurements. Powders of SiO2, Fe2O3, Al2O3, CaO that are found in the lunar regolith and JSC-1A were considered.

  3. Magnetars: recent discoveries and synergies with multi-band facilities

    NASA Astrophysics Data System (ADS)

    Rea, N.

    2016-06-01

    In this talk I will review the recent discoveries and theoretical advances in the field of highly magnetized neutron stars (aka magnetars). I will focus on the large impact that XMM-Newton has in our understanding of these extreme sources. Furthermore, I will shortly review on the multi-band emission of magnetars and on the potential synergies with other facilities.

  4. Quantum waveguide theory of the Josephson effect in multiband superconductors

    NASA Astrophysics Data System (ADS)

    Nappi, C.; Romeo, F.; Sarnelli, E.; Citro, R.

    2015-12-01

    We formulate a quantum waveguide theory of the Josephson effect in multiband superconductors, with special emphasis on iron-based materials. By generalizing the boundary conditions of the scattering problem, we first determine the Andreev levels spectrum and then derive an explicit expression for the Josephson current which generalizes the formula of the single-band case. In deriving the results, we provide a second quantization field theory, allowing us to evaluate the current-phase relation and the Josephson current fluctuations in multiband systems. We present results for two different order parameter symmetries, namely s± and s++, which are relevant in multiband systems. The obtained results show that the s± symmetry can support π states which are absent in the s++ case. We also argue that there is a certain fragility of the Josephson current against phase fluctuations in the s++ case. The temperature dependence of the Josephson critical current is also analyzed and we find, for both the order parameter symmetries, remarkable violations of the Ambegaokar-Baratoff relation. The results are relevant in view of possible experiments aimed at investigating the order parameter symmetry of multiband superconductors using mesoscopic Josephson junctions.

  5. Modulation of whistler waves in nonthermal plasmas

    SciTech Connect

    Rios, L. A.; Galvao, R. M. O.

    2011-02-15

    The modulation of whistler waves in nonthermal plasmas is investigated. The dynamics of the magnetized plasma is described by the fluid equations and the electron velocity distribution function is modeled via a nonthermal {kappa} distribution. A multiscale perturbation analysis based on the Krylov-Bogoliubov-Mitropolsky method is carried out and the nonlinear Schroedinger equation governing the modulation of the high-frequency whistler is obtained. The effect of the superthermal electrons on the stability of the wave envelope and soliton formation is discussed and a comparison with previous results is presented.

  6. Nonthermal Components in the Large Scale Structure

    NASA Astrophysics Data System (ADS)

    Miniati, Francesco

    2004-12-01

    I address the issue of nonthermal processes in the large scale structure of the universe. After reviewing the properties of cosmic shocks and their role as particle accelerators, I discuss the main observational results, from radio to γ-ray and describe the processes that are thought be responsible for the observed nonthermal emissions. Finally, I emphasize the important role of γ-ray astronomy for the progress in the field. Non detections at these photon energies have already allowed us important conclusions. Future observations will tell us more about the physics of the intracluster medium, shocks dissipation and CR acceleration.

  7. Nonthermal WIMPs and primordial black holes

    NASA Astrophysics Data System (ADS)

    Georg, Julian; Şengör, Gizem; Watson, Scott

    2016-06-01

    Nonthermal histories for the early universe have received notable attention as they are a rich source of phenomenology, while also being well motivated by top-down approaches to beyond the Standard Model physics. The early (pre-big bang nucleosynthesis) matter phase in these models leads to enhanced growth of density perturbations on sub-Hubble scales. Here, we consider whether primordial black hole formation associated with the enhanced growth is in conflict with existing observations. Such constraints depend on the tilt of the primordial power spectrum, and we find that nonthermal histories are tightly constrained in the case of a significantly blue spectrum. Alternatively, if dark matter is taken to be of nonthermal origin, we can restrict the primordial power spectrum on scales inaccessible to cosmic microwave background and large scale structure observations. We establish constraints for a wide range of scalar masses (reheat temperatures) with the most stringent bounds resulting from the formation of 1015 g black holes. These black holes would be evaporating today and are constrained by FERMI observations. We also consider whether the breakdown of the coherence of the scalar oscillations on subhorizon scales can lead to a Jean's pressure preventing black hole formation and relaxing our constraints. Our main conclusion is that primordial black hole constraints, combined with existing constraints on nonthermal weakly interacting massive particles, favor a primordial spectrum closer to scale invariance or a red tilted spectrum.

  8. Enhanced integrated nonthermal treatment system study

    SciTech Connect

    Biagi, C.; Schwinkendorf, B.; Teheranian, B.

    1997-02-01

    The purpose of the Enhanced Nonthermal Treatment Systems (ENTS) study is to evaluate alternative configurations of one of the five systems evaluated in the Integrated Nonthermal Treatment Systems (INTS) study. Five alternative configurations are evaluated. Each is designed to enhance the final waste form performance by replacing grout with improved stabilization technologies, or to improve system performance by improving the destruction efficiency for organic contaminants. AU enhanced systems are alternative configurations of System NT-5, which has the following characteristics: Nonthermal System NT-5: (1) catalytic wet oxidation (CWO) to treat organic material including organic liquids, sludges, and soft (or combustible) debris, (2) thermal desorption of inorganic sludge and process residue, (3) washing of soil and inorganic debris with treatment by CWO of removed organic material, (4) metal decontamination by abrasive blasting, (5) stabilization of treated sludge, soil, debris, and untreated debris with entrained contamination in grout, and (6) stabilization of inorganic sludge, salts and secondary waste in polymer. System NT-5 was chosen because it was designed to treat combustible debris thereby minimizing the final waste form volume, and because it uses grout for primary stabilization. The enhanced nonthermal systems were studied to determine the cost and performance impact of replacing grout (a commonly used stabilization agent in the DOE complex) with improved waste stabilization methods such as vitrification and polymer.

  9. Mechanisms of interaction of non-thermal plasma with living cells

    NASA Astrophysics Data System (ADS)

    Kalghatgi, Sameer Ulhas

    independent, suggesting that non-thermal plasma may induce formation of bulky lesions unlike ionizing radiation (IR) or H2O2 which primarily produce DNA double strand breaks. Moreover, it is found that the pathway by which plasma generated oxidative stress is transferred across cellular membranes does not involve lipid peroxidation by-products, although lipid peroxidation does occur.

  10. Distinct magnetic signatures of fractional vortex configurations in multiband superconductors

    SciTech Connect

    Silva, R. M. da; Domínguez, D.; Aguiar, J. Albino

    2014-12-08

    Vortices carrying fractions of a flux quantum are predicted to exist in multiband superconductors, where vortex core can split between multiple band-specific components of the superconducting condensate. Using the two-component Ginzburg-Landau model, we examine such vortex configurations in a two-band superconducting slab in parallel magnetic field. The fractional vortices appear due to the band-selective vortex penetration caused by different thresholds for vortex entry within each band-condensate, and stabilize near the edges of the sample. We show that the resulting fractional vortex configurations leave distinct fingerprints in the static measurements of the magnetization, as well as in ac dynamic measurements of the magnetic susceptibility, both of which can be readily used for the detection of these fascinating vortex states in several existing multiband superconductors.

  11. A Matrix Pencil Algorithm Based Multiband Iterative Fusion Imaging Method

    PubMed Central

    Zou, Yong Qiang; Gao, Xun Zhang; Li, Xiang; Liu, Yong Xiang

    2016-01-01

    Multiband signal fusion technique is a practicable and efficient way to improve the range resolution of ISAR image. The classical fusion method estimates the poles of each subband signal by the root-MUSIC method, and some good results were get in several experiments. However, this method is fragile in noise for the proper poles could not easy to get in low signal to noise ratio (SNR). In order to eliminate the influence of noise, this paper propose a matrix pencil algorithm based method to estimate the multiband signal poles. And to deal with mutual incoherent between subband signals, the incoherent parameters (ICP) are predicted through the relation of corresponding poles of each subband. Then, an iterative algorithm which aimed to minimize the 2-norm of signal difference is introduced to reduce signal fusion error. Applications to simulate dada verify that the proposed method get better fusion results at low SNR. PMID:26781194

  12. Ginzburg-Landau theory for multiband superconductors: Microscopic derivation

    NASA Astrophysics Data System (ADS)

    Orlova, N. V.; Shanenko, A. A.; Milošević, M. V.; Peeters, F. M.; Vagov, A. V.; Axt, V. M.

    2013-04-01

    A procedure to derive the Ginzburg-Landau (GL) theory from the multiband BCS Hamiltonian is developed in a general case with an arbitrary number of bands and arbitrary interaction matrix. It combines the standard Gor'kov truncation and a subsequent reconstruction in order to match accuracies of the obtained terms. This reconstruction recovers the phenomenological GL theory as obtained from the Landau model of phase transitions but offers explicit microscopic expressions for the relevant parameters. Detailed calculations are presented for a three-band system treated as a prototype multiband superconductor. It is demonstrated that the symmetry in the coupling matrix may lead to the chiral ground state with the phase frustration, typical for systems with broken time-reversal symmetry.

  13. A Matrix Pencil Algorithm Based Multiband Iterative Fusion Imaging Method

    NASA Astrophysics Data System (ADS)

    Zou, Yong Qiang; Gao, Xun Zhang; Li, Xiang; Liu, Yong Xiang

    2016-01-01

    Multiband signal fusion technique is a practicable and efficient way to improve the range resolution of ISAR image. The classical fusion method estimates the poles of each subband signal by the root-MUSIC method, and some good results were get in several experiments. However, this method is fragile in noise for the proper poles could not easy to get in low signal to noise ratio (SNR). In order to eliminate the influence of noise, this paper propose a matrix pencil algorithm based method to estimate the multiband signal poles. And to deal with mutual incoherent between subband signals, the incoherent parameters (ICP) are predicted through the relation of corresponding poles of each subband. Then, an iterative algorithm which aimed to minimize the 2-norm of signal difference is introduced to reduce signal fusion error. Applications to simulate dada verify that the proposed method get better fusion results at low SNR.

  14. Superconductivity between standard types: Multiband versus single-band materials

    NASA Astrophysics Data System (ADS)

    Vagov, A.; Shanenko, A. A.; Milošević, M. V.; Axt, V. M.; Vinokur, V. M.; Aguiar, J. Albino; Peeters, F. M.

    2016-05-01

    In the nearest vicinity of the critical temperature, types I and II of conventional single-band superconductors interchange at the Ginzburg-Landau parameter κ =1 /√{2 } . At lower temperatures this point unfolds into a narrow but finite interval of κ 's, shaping an intertype (transitional) domain in the (κ ,T ) plane. In the present work, based on the extended Ginzburg-Landau formalism, we show that the same picture of the two standard types with the transitional domain in between applies also to multiband superconductors. However, the intertype domain notably widens in the presence of multiple bands and can become extremely large when the system has a significant disparity between the band parameters. It is concluded that many multiband superconductors, such as recently discovered borides and iron-based materials, can belong to the intertype regime.

  15. A multiband perfect absorber based on hyperbolic metamaterials

    PubMed Central

    Sreekanth, Kandammathe Valiyaveedu; ElKabbash, Mohamed; Alapan, Yunus; Rashed, Alireza R.; Gurkan, Umut A.; Strangi, Giuseppe

    2016-01-01

    In recent years, considerable research efforts have been focused on near-perfect and perfect light absorption using metamaterials spanning frequency ranges from microwaves to visible frequencies. This relatively young field is currently facing many challenges that hampers its possible practical applications. In this paper, we present grating coupled-hyperbolic metamaterials (GC-HMM) as multiband perfect absorber that can offer extremely high flexibility in engineering the properties of electromagnetic absorption. The fabricated GC-HMMs exhibit several highly desirable features for technological applications such as polarization independence, wide angle range, broad- and narrow- band modes, multiband perfect and near perfect absorption in the visible to near-IR and mid-IR spectral range. In addition, we report a direct application of the presented system as an absorption based plasmonic sensor with a record figure of merit for this class of sensors. PMID:27188789

  16. A Matrix Pencil Algorithm Based Multiband Iterative Fusion Imaging Method.

    PubMed

    Zou, Yong Qiang; Gao, Xun Zhang; Li, Xiang; Liu, Yong Xiang

    2016-01-01

    Multiband signal fusion technique is a practicable and efficient way to improve the range resolution of ISAR image. The classical fusion method estimates the poles of each subband signal by the root-MUSIC method, and some good results were get in several experiments. However, this method is fragile in noise for the proper poles could not easy to get in low signal to noise ratio (SNR). In order to eliminate the influence of noise, this paper propose a matrix pencil algorithm based method to estimate the multiband signal poles. And to deal with mutual incoherent between subband signals, the incoherent parameters (ICP) are predicted through the relation of corresponding poles of each subband. Then, an iterative algorithm which aimed to minimize the 2-norm of signal difference is introduced to reduce signal fusion error. Applications to simulate dada verify that the proposed method get better fusion results at low SNR. PMID:26781194

  17. A multiband perfect absorber based on hyperbolic metamaterials.

    PubMed

    Sreekanth, Kandammathe Valiyaveedu; ElKabbash, Mohamed; Alapan, Yunus; Rashed, Alireza R; Gurkan, Umut A; Strangi, Giuseppe

    2016-01-01

    In recent years, considerable research efforts have been focused on near-perfect and perfect light absorption using metamaterials spanning frequency ranges from microwaves to visible frequencies. This relatively young field is currently facing many challenges that hampers its possible practical applications. In this paper, we present grating coupled-hyperbolic metamaterials (GC-HMM) as multiband perfect absorber that can offer extremely high flexibility in engineering the properties of electromagnetic absorption. The fabricated GC-HMMs exhibit several highly desirable features for technological applications such as polarization independence, wide angle range, broad- and narrow- band modes, multiband perfect and near perfect absorption in the visible to near-IR and mid-IR spectral range. In addition, we report a direct application of the presented system as an absorption based plasmonic sensor with a record figure of merit for this class of sensors. PMID:27188789

  18. A multiband perfect absorber based on hyperbolic metamaterials

    NASA Astrophysics Data System (ADS)

    Sreekanth, Kandammathe Valiyaveedu; Elkabbash, Mohamed; Alapan, Yunus; Rashed, Alireza R.; Gurkan, Umut A.; Strangi, Giuseppe

    2016-05-01

    In recent years, considerable research efforts have been focused on near-perfect and perfect light absorption using metamaterials spanning frequency ranges from microwaves to visible frequencies. This relatively young field is currently facing many challenges that hampers its possible practical applications. In this paper, we present grating coupled-hyperbolic metamaterials (GC-HMM) as multiband perfect absorber that can offer extremely high flexibility in engineering the properties of electromagnetic absorption. The fabricated GC-HMMs exhibit several highly desirable features for technological applications such as polarization independence, wide angle range, broad- and narrow- band modes, multiband perfect and near perfect absorption in the visible to near-IR and mid-IR spectral range. In addition, we report a direct application of the presented system as an absorption based plasmonic sensor with a record figure of merit for this class of sensors.

  19. Multi-band terahertz active device with complementary metamaterial

    SciTech Connect

    Qiao, Shen; Zhang, Yaxin Sun, Linlin; Sun, Han; Xu, Gaiqi; Zhao, Yuncheng; Yang, Ziqiang; Liang, Shixiong

    2015-09-28

    We describe a multi-band terahertz-active device using a composite structure made of complementary metamaterial and doped silicon that can be dynamically controlled. This special complementary metamaterial exhibits three resonances that produce three pass-bands. The pass-bands can be uniformly manipulated by exploiting the photoinduced characteristics of the doped silicon. Simulations were performed to analyze the magnetic field and surface current distributions. The simulation results agree well with experimental results obtained from terahertz time-domain spectroscopy. Using an 808-nm-wavelength laser beam, a modulation depth of up to 80% was obtained. In numerical simulations, we used a conductivity mode to characterize photoinduction. The development of multi-band terahertz-active devices has many potential applications, for example, in filters, modulators, switches, and sensors.

  20. Homogenization limit for a multiband effective mass model in heterostructures

    SciTech Connect

    Morandi, O.

    2014-06-15

    We study the homogenization limit of a multiband model that describes the quantum mechanical motion of an electron in a quasi-periodic crystal. In this approach, the distance among the atoms that constitute the material (lattice parameter) is considered a small quantity. Our model include the description of materials with variable chemical composition, intergrowth compounds, and heterostructures. We derive the effective multiband evolution system in the framework of the kp approach. We study the well posedness of the mathematical problem. We compare the effective mass model with the standard kp models for uniform and non-uniforms crystals. We show that in the limit of vanishing lattice parameter, the particle density obtained by the effective mass model, converges to the exact probability density of the particle.

  1. LAMBDAR: Lambda Adaptive Multi-Band Deblending Algorithm in R

    NASA Astrophysics Data System (ADS)

    Wright, Angus H.

    2016-04-01

    LAMBDAR measures galaxy fluxes from an arbitrary FITS image, covering an arbitrary photometric wave-band, when provided all parameters needed to construct galactic apertures at the required locations for multi-band matched aperture galactic photometry. Through sophisticated matched aperture photometry, the package develops robust Spectral Energy Distributions (SEDs) and accurately establishes the physical properties of galactic objects. LAMBDAR was based on a package detailed in Bourne et al. (2012) that determined galactic fluxes in low resolution Herschel images.

  2. Multiband RF pulses with improved performance via convex optimization

    NASA Astrophysics Data System (ADS)

    Shang, Hong; Larson, Peder E. Z.; Kerr, Adam; Reed, Galen; Sukumar, Subramaniam; Elkhaled, Adam; Gordon, Jeremy W.; Ohliger, Michael A.; Pauly, John M.; Lustig, Michael; Vigneron, Daniel B.

    2016-01-01

    Selective RF pulses are commonly designed with the desired profile as a low pass filter frequency response. However, for many MRI and NMR applications, the spectrum is sparse with signals existing at a few discrete resonant frequencies. By specifying a multiband profile and releasing the constraint on "don't-care" regions, the RF pulse performance can be improved to enable a shorter duration, sharper transition, or lower peak B1 amplitude. In this project, a framework for designing multiband RF pulses with improved performance was developed based on the Shinnar-Le Roux (SLR) algorithm and convex optimization. It can create several types of RF pulses with multiband magnitude profiles, arbitrary phase profiles and generalized flip angles. The advantage of this framework with a convex optimization approach is the flexible trade-off of different pulse characteristics. Designs for specialized selective RF pulses for balanced SSFP hyperpolarized (HP) 13C MRI, a dualband saturation RF pulse for 1H MR spectroscopy, and a pre-saturation pulse for HP 13C study were developed and tested.

  3. Multiband RF pulses with improved performance via convex optimization.

    PubMed

    Shang, Hong; Larson, Peder E Z; Kerr, Adam; Reed, Galen; Sukumar, Subramaniam; Elkhaled, Adam; Gordon, Jeremy W; Ohliger, Michael A; Pauly, John M; Lustig, Michael; Vigneron, Daniel B

    2016-01-01

    Selective RF pulses are commonly designed with the desired profile as a low pass filter frequency response. However, for many MRI and NMR applications, the spectrum is sparse with signals existing at a few discrete resonant frequencies. By specifying a multiband profile and releasing the constraint on "don't-care" regions, the RF pulse performance can be improved to enable a shorter duration, sharper transition, or lower peak B1 amplitude. In this project, a framework for designing multiband RF pulses with improved performance was developed based on the Shinnar-Le Roux (SLR) algorithm and convex optimization. It can create several types of RF pulses with multiband magnitude profiles, arbitrary phase profiles and generalized flip angles. The advantage of this framework with a convex optimization approach is the flexible trade-off of different pulse characteristics. Designs for specialized selective RF pulses for balanced SSFP hyperpolarized (HP) (13)C MRI, a dualband saturation RF pulse for (1)H MR spectroscopy, and a pre-saturation pulse for HP (13)C study were developed and tested. PMID:26754063

  4. The Effect of a Nonthermal Tail on the Sunyaev-Zeldovich Effect in Clusters of Galaxies.

    PubMed

    Blasi; Olinto; Stebbins

    2000-06-01

    We study the spectral distortions of the cosmic microwave background radiation induced by the effect in clusters of galaxies when the target electrons have a modified Maxwell-Boltzmann distribution with a high-energy nonthermal tail. Bremsstrahlung radiation from this type of electron distribution may explain the suprathermal X-ray emission observed in some clusters such as the Coma Cluster and A2199 and serve as an alternative to the classical but problematic inverse Compton scattering interpretation. We show that the Sunyaev-Zeldovich effect can be used as a powerful tool to probe the electron distribution in clusters of galaxies and discriminate among these different interpretations of the X-ray excess. The existence of a nonthermal tail can have important consequences for cluster-based estimators of cosmological parameters. PMID:10835301

  5. Sneutrino hybrid inflation and nonthermal leptogenesis

    SciTech Connect

    Antusch, Stefan; Baumann, Jochen P.; Domcke, Valerie F.; Kostka, Philipp M. E-mail: jbaumann@mppmu.mpg.de E-mail: kostka@mppmu.mpg.de

    2010-10-01

    In sneutrino hybrid inflation the superpartner of one of the right-handed neutrinos involved in the seesaw mechanism plays the role of the inflaton field. It obtains its large mass after the ''waterfall'' phase transition which ends hybrid inflation. After this phase transition the oscillations of the sneutrino inflaton field may dominate the universe and efficiently produce the baryon asymmetry of the universe via nonthermal leptogenesis. We investigate the conditions under which inflation, with primordial perturbations in accordance with the latest WMAP results, as well as successful nonthermal leptogenesis can be realized simultaneously within the sneutrino hybrid inflation scenario. We point out which requirements successful inflation and leptogenesis impose on the seesaw parameters, i.e. on the Yukawa couplings and the mass of the right-handed (s)neutrino, and derive the predictions for the CMB observables in terms of the right-handed (s)neutrino mass and the other relevant model parameters.

  6. Bacterial decontamination using ambient pressure nonthermal discharges

    SciTech Connect

    Birmingham, J.G.; Hammerstrom, D.J.

    2000-02-01

    Atmospheric pressure nonthermal plasmas can efficiently deactivate bacteria in gases, liquids, and on surfaces, as well as can decompose hazardous chemicals. This paper focuses on the changes to bacterial spores and toxic biochemical compounds, such as mycotoxins, after their treatment in ambient pressure discharges. The ability of nonthermal plasmas to decompose toxic chemicals and deactivate hazardous biological materials has been applied to sterilizing medical instruments, ozonating water, and purifying air. In addition, the fast lysis of bacterial spores and other cells has led us to include plasma devices within pathogen detection instruments, where nucleic acids must be accessed. Decontaminating chemical and biological warfare materials from large, high value targets such as building surfaces, after a terrorist attack, are especially challenging. A large area plasma decontamination technology is described.

  7. Quantum nonthermal effect of the Vaidya-Bonner-de Sitter black hole

    NASA Astrophysics Data System (ADS)

    Pan, Wei-Zhen; Yang, Xue-Jun; Yu, Guo-Xiang

    2014-02-01

    Using the Hamilton-Jacobi equation of a scalar particle in the curve space-time and a correct-dimension new tortoise coordinate transformation, the quantum nonthermal radiation of the Vaidya-Bonner-de Sitter black hole is investigated. The energy condition for the occurrence of the Starobinsky-Unruh process is obtained. The event horizon surface gravity and the Hawking temperature on the event horizon are also given.

  8. Model for fluctuating inflaton coupling: sneutrino induced adiabatic perturbations and nonthermal leptogenesis.

    PubMed

    Mazumdar, Anupam

    2004-06-18

    We discuss a unique possibility of generating adiabatic density perturbations and leptogenesis from the spatial fluctuations of the inflaton decay rate. The key assumption is that the initial isocurvature perturbations are created in the right-handed sneutrino sector during inflation which is then converted into adiabatic perturbations when the inflaton decays. We discuss distinct imprints on the cosmic microwave background radiation, which can distinguish nonthermal versus thermal leptogenesis. PMID:15245073

  9. Nonthermal gravitino production in tribrid inflation

    NASA Astrophysics Data System (ADS)

    Antusch, Stefan; Dutta, Koushik

    2015-10-01

    We investigate nonthermal gravitino production after tribrid inflation in supergravity, which is a variant of supersymmetric hybrid inflation where three fields are involved in the inflationary model and where the inflaton field resides in the matter sector of the theory. In contrast to conventional supersymmetric hybrid inflation, where nonthermal gravitino production imposes severe constraints on the inflationary model, we find that the "nonthermal gravitino problem" is generically absent in models of tribrid inflation, mainly due to two effects: (i) With the inflaton in tribrid inflation (after inflation) being lighter than the waterfall field, the latter has a second decay channel with a much larger rate than for the decay into gravitinos. This reduces the branching ratio for the decay of the waterfall field into gravitinos. (ii) The inflaton generically decays later than the waterfall field, and it does not produce gravitinos when it decays. This leads to a dilution of the gravitino population from the decays of the waterfall field. The combination of both effects generically leads to a strongly reduced gravitino production in tribrid inflation.

  10. Multiband design boosts resolution of imaging radar

    NASA Astrophysics Data System (ADS)

    Parnell, William C.

    1988-09-01

    The design of a coherent high-resolution polarization-agile mapping and target-identification radar operating at 35, 95, and 140 GHz is described in detail and illustrated with circuit diagrams and graphs of antenna radiation patterns; lists of system components with their model numbers and manufacturers are also provided. The radar is intended for use on a target-range tower or in other remote locations and employs interchangeable front-end modules to achieve the dual-band operation required for development of real-time multispectral target-recognition algorithms.

  11. Fuel injector utilizing non-thermal plasma activation

    SciTech Connect

    Coates, Don M.; Rosocha, Louis A.

    2009-12-01

    A non-thermal plasma assisted combustion fuel injector that uses an inner and outer electrode to create an electric field from a high voltage power supply. A dielectric material is operatively disposed between the two electrodes to prevent arcing and to promote the formation of a non-thermal plasma. A fuel injector, which converts a liquid fuel into a dispersed mist, vapor, or aerosolized fuel, injects into the non-thermal plasma generating energetic electrons and other highly reactive chemical species.

  12. Gain enhancement of a multiband resonator using defected ground surface on epoxy woven glass material.

    PubMed

    Alam, Md Shahidul; Islam, Mohammad Tariqul; Arshad, Haslina

    2014-01-01

    A multiband microstrip resonator is proposed in this study which is realized through a rectangular radiator with embedded symmetrical rectangular slots in it and a defected ground surface. The study is presented with detailed parametric analyses to understand the effect of various design parameters. The design and analyses are performed using the FIT based full-wave electromagnetic simulator CST microwave studio suite. With selected parameter values, the resonator showed a peak gain of 5.85 dBi at 5.2 GHz, 6.2 dBi at 8.3 GHz, 3.9 dBi at 9.5 GHz, 5.9 dBi at 12.2 GHz, and 4.7 dBi at 14.6 GHz. Meanwhile, the main lobe magnitude and the 3 dB angular beam width are 6.2 dBi and 86°, 5.9 dBi and 53.7°, 8.5 dBi and 43.9°, 8.6 dBi and 42.1°, and 4.7 dBi and 30.1°, respectively, at the resonant frequencies. The overall resonator has a compact dimension of 0.52λ  × 0.52λ  × 0.027λ at the lower resonant frequency. For practical validation, a lab prototype was built on a 1.6 mm thick epoxide woven glass fabric dielectric material which is measured using a vector network analyzer and within an anechoic chamber. The comparison between the simulated and measured results showed a very good understanding, which implies the practical suitability of the proposed multiband resonator design. PMID:24883354

  13. Radio frequency electromagnetic field compliance assessment of multi-band and MIMO equipped radio base stations.

    PubMed

    Thors, Björn; Thielens, Arno; Fridén, Jonas; Colombi, Davide; Törnevik, Christer; Vermeeren, Günter; Martens, Luc; Joseph, Wout

    2014-05-01

    In this paper, different methods for practical numerical radio frequency exposure compliance assessments of radio base station products were investigated. Both multi-band base station antennas and antennas designed for multiple input multiple output (MIMO) transmission schemes were considered. For the multi-band case, various standardized assessment methods were evaluated in terms of resulting compliance distance with respect to the reference levels and basic restrictions of the International Commission on Non-Ionizing Radiation Protection. Both single frequency and multiple frequency (cumulative) compliance distances were determined using numerical simulations for a mobile communication base station antenna transmitting in four frequency bands between 800 and 2600 MHz. The assessments were conducted in terms of root-mean-squared electromagnetic fields, whole-body averaged specific absorption rate (SAR) and peak 10 g averaged SAR. In general, assessments based on peak field strengths were found to be less computationally intensive, but lead to larger compliance distances than spatial averaging of electromagnetic fields used in combination with localized SAR assessments. For adult exposure, the results indicated that even shorter compliance distances were obtained by using assessments based on localized and whole-body SAR. Numerical simulations, using base station products employing MIMO transmission schemes, were performed as well and were in agreement with reference measurements. The applicability of various field combination methods for correlated exposure was investigated, and best estimate methods were proposed. Our results showed that field combining methods generally considered as conservative could be used to efficiently assess compliance boundary dimensions of single- and dual-polarized multicolumn base station antennas with only minor increases in compliance distances. PMID:24523232

  14. Gain Enhancement of a Multiband Resonator Using Defected Ground Surface on Epoxy Woven Glass Material

    PubMed Central

    Islam, Mohammad Tariqul; Arshad, Haslina

    2014-01-01

    A multiband microstrip resonator is proposed in this study which is realized through a rectangular radiator with embedded symmetrical rectangular slots in it and a defected ground surface. The study is presented with detailed parametric analyses to understand the effect of various design parameters. The design and analyses are performed using the FIT based full-wave electromagnetic simulator CST microwave studio suite. With selected parameter values, the resonator showed a peak gain of 5.85 dBi at 5.2 GHz, 6.2 dBi at 8.3 GHz, 3.9 dBi at 9.5 GHz, 5.9 dBi at 12.2 GHz, and 4.7 dBi at 14.6 GHz. Meanwhile, the main lobe magnitude and the 3 dB angular beam width are 6.2 dBi and 86°, 5.9 dBi and 53.7°, 8.5 dBi and 43.9°, 8.6 dBi and 42.1°, and 4.7 dBi and 30.1°, respectively, at the resonant frequencies. The overall resonator has a compact dimension of 0.52λ  × 0.52λ  × 0.027λ at the lower resonant frequency. For practical validation, a lab prototype was built on a 1.6 mm thick epoxide woven glass fabric dielectric material which is measured using a vector network analyzer and within an anechoic chamber. The comparison between the simulated and measured results showed a very good understanding, which implies the practical suitability of the proposed multiband resonator design. PMID:24883354

  15. Multiband effects on the superconductivity in doped C[sub 60

    SciTech Connect

    Choi, H. ); Rice, M.J. )

    1994-03-01

    We consider multiband effects on the superconductivity in the alkali-doped fullerenes. It is shown that the multiband superconducting gap is reduced to the well-known Bardeen-Cooper-Schrieffer expression due to a cyclic symmetry in the orientationally ordered phases, thereby justifying many previous works assuming single-band [ital s]-wave pairing without considering several conduction bands explicitly.

  16. Low-Cost Dielectric Substrate for Designing Low Profile Multiband Monopole Microstrip Antenna

    PubMed Central

    Ahsan, M. R.; Islam, M. T.; Habib Ullah, M.; Arshad, H.; Mansor, M. F.

    2014-01-01

    This paper proposes a small sized, low-cost multiband monopole antenna which can cover the WiMAX bands and C-band. The proposed antenna of 20 × 20 mm2 radiating patch is printed on cost effective 1.6 mm thick fiberglass polymer resin dielectric material substrate and fed by 4 mm long microstrip line. The finite element method based, full wave electromagnetic simulator HFSS is efficiently utilized for designing and analyzing the proposed antenna and the antenna parameters are measured in a standard far-field anechoic chamber. The experimental results show that the prototype of the antenna has achieved operating bandwidths (voltage stand wave ratio (VSWR) less than 2) 360 MHz (2.53–2.89 GHz) and 440 MHz (3.47–3.91 GHz) for WiMAX and 1550 MHz (6.28–7.83 GHz) for C-band. The simulated and measured results for VSWR, radiation patterns, and gain are well matched. Nearly omnidirectional radiation patterns are achieved and the peak gains are of 3.62 dBi, 3.67 dBi, and 5.7 dBi at 2.66 GHz, 3.65 GHz, and 6.58 GHz, respectively. PMID:25136648

  17. Low-cost dielectric substrate for designing low profile multiband monopole microstrip antenna.

    PubMed

    Ahsan, M R; Islam, M T; Habib Ullah, M; Arshad, H; Mansor, M F

    2014-01-01

    This paper proposes a small sized, low-cost multiband monopole antenna which can cover the WiMAX bands and C-band. The proposed antenna of 20 × 20 mm(2) radiating patch is printed on cost effective 1.6 mm thick fiberglass polymer resin dielectric material substrate and fed by 4 mm long microstrip line. The finite element method based, full wave electromagnetic simulator HFSS is efficiently utilized for designing and analyzing the proposed antenna and the antenna parameters are measured in a standard far-field anechoic chamber. The experimental results show that the prototype of the antenna has achieved operating bandwidths (voltage stand wave ratio (VSWR) less than 2) 360 MHz (2.53-2.89 GHz) and 440 MHz (3.47-3.91 GHz) for WiMAX and 1550 MHz (6.28-7.83 GHz) for C-band. The simulated and measured results for VSWR, radiation patterns, and gain are well matched. Nearly omnidirectional radiation patterns are achieved and the peak gains are of 3.62 dBi, 3.67 dBi, and 5.7 dBi at 2.66 GHz, 3.65 GHz, and 6.58 GHz, respectively. PMID:25136648

  18. Hot Flow Model for Low Luminosity AGNs and Black Hole Binaries: the Role and Origin of Non-thermal Electrons

    NASA Astrophysics Data System (ADS)

    Niedzwiecki, Andrzej; Xie, Fu-Guo; Stepnik, Agnieszka

    2014-08-01

    Optically thin, two-temperature accretion flows are widely considered as a relevant accretion mode below ~0.01 LEdd in AGNs as well as in X-ray binaries. We study spectral formation in such flows using a refined model with a fully general relativistic description of both the radiative (leptonic and hadronic) and hydrodynamic processes, and with an exact treatment of global Comptonization. We point out that basic properties of two-temperature flows determine the relative strengths of the synchrotron radiation of thermal electrons and non-thermal electrons from charged-pion decay, in a manner consistent with observations. In AGNs, the non-thermal synchrotron dominates the seed photon input down to ~10-5 LEdd and it allows to explain the X-ray spectral index-Eddington ratio relation as well as the cut-off energies measured in the best-studied AGNs; the (standard) model with the thermal synchrotron being the main source of seed photons does not agree with these observations. For stellar-mass black holes, non-thermal electrons from hadronic processes become important only above ~0.01 LEdd (and may be relevant for the non-thermal tails observed in luminous hard states of Cyg X-1 and GX 339-4) and we find that the thermal synchrotron provides a sufficient seed photon flux to explain observations of black hole transients below ~0.01 LEdd. We also note that non-thermal acceleration processes in hot flows are constrained by comparisons of the predicted gamma-ray fluxes (from neutral pion decay) with Fermi-LAT upper limits. For NGC 4151, it limits the energy content in the non-thermal component of proton distribution to at most 1 per cent.

  19. Material classification based on multi-band polarimetric images fusion

    NASA Astrophysics Data System (ADS)

    Zhao, Yongqiang; Pan, Quan; Zhang, Hongcai

    2006-05-01

    Polarization imparted by surface reflections contains unique and discriminatory signatures which may augment spectral target-detection techniques. With the development of multi-band polarization imaging technology, it is becoming more and more important on how to integrate polarimetric, spatial and spectral information to improve target discrimination. In this study, investigations were performed on combining multi-band polarimetric images through false color mapping and wavelet integrated image fusion method. The objective of this effort was to extend the investigation of the use of polarized light to target detection and material classification. As there is great variation in polarization in and between each of the bandpasses, and this variation is comparable to the magnitude of the variation intensity. At the same time, the contrast in polarization is greater than for intensity, and that polarization contrast increases as intensity contrast decreases. It is also pointed out that chromaticity can be used to make targets stand out more clearly against background, and material can be divided into conductor and nonconductor through polarization information. So, through false color mapping, the difference part of polarimetric information between each of the bandpasses and common part of polarimetric information in each of the bandpasses are combined, in the resulting image the conductor and nonconductor are assigned different color. Then panchromatic polarimetric images are fused with resulting image through wavelet decomposition, the final fused image have more detail information and more easy identification. This study demonstrated, using digital image data collected by imaging spectropolarimeter, multi-band imaging polarimetry is likely to provide an advantage in target detection and material classification.

  20. Design of multiband metamaterial absorber based on artificial magnetic conductor

    NASA Astrophysics Data System (ADS)

    Dang, Kezheng; He, Zijian; Li, Zhigang; Miao, Lei; Liu, Hao

    2015-10-01

    We present a general method to design multiband absorber by replacing the ground plane in a conventional metamaterial absorber with an artificial magnetic conductor. Due to its unique property of in-phase reflection at some specific frequency, the artificial magnetic conductor is used to introduce new absorption in the operation band. Meanwhile, out of the in-phase reflection band, the original absorbing capability of the absorber is reserved. To demonstrate it, we design a metamaterial absorber comprising three layers which are grids patterned resistive frequency selective surface, dielectric layer and the ground plane respectively. With an appropriate design, the absorber performs an absorbing peak at about 10 GHz. Then, we utilize a single band artificial magnetic conductor at 6.25 GHz and a dual-band one at 6.27 GHz and 8.17 GHz, which are both lossy and comprised of patches array varying in periodic size with a thickness of 0.6 mm, to replace the ground plane in the metamaterial absorber separately. The reflectivity of these multiband absorbers are simulated, and experiments are carried out later. Experimental results agree well with the simulations. All results verified that the method presented at the beginning is effective. The results show that additional absorptions exist at the frequencies where microwaves are nearly reflected in phase on the artificial magnetic conductor. Meanwhile the original absorbing capability of the metamaterial absorber has been preserved mostly. Based on the artificial magnetic conductor, the multiband absorber performs better with an increasing absorption bandwidth from 8.5 GHz to 10 GHz compared to the metamaterial absorber.

  1. BOREAS TE-6 Multiband Vegetation Imager Data

    NASA Technical Reports Server (NTRS)

    Hall, Forrest G. (Editor); Curd, Shelaine (Editor); Kucharik, Christopher J.

    2000-01-01

    The BOREAS TE-6 team collected data in support of its efforts to examine the influence of vegetation and climate on the major carbon fluxes in boreal tree species. A newly developed ground-based canopy imaging system called an MVI was tested and used by the BOREAS TE-06 team to collect measurements of the canopy crap fraction (sky fraction), canopy gap-size distribution (size and frequency of gaps between foliage in canopy), branch architecture, and leaf angle distribution (fraction of leaf area in specific leaf inclination classes assuming azimuthal symmetry). Measurements of the canopy gap-size distribution are used to derive canopy clumping indices that can be used to adjust indirect LAI measurements made in nonrandom forests. These clumping factors will also help to describe the radiation penetration in clumped canopies more accurately by allowing for simple adjustments to Beer's law. Measurements of the above quantities were obtained at BOREAS NSA-OJP site in IFC-2 in 1994, at the SSA-OA in July 1995, and at the SSA-OBS and SSA-OA sites in IFC-2 in 1996. Modeling studies were also performed to further validate MVI measurements and to gain a more complete understanding of boreal forest canopy architecture. By using MVI measurements and Monte Carlo simulations, clumping indices as a function of zenith angle were derived for the three main boreal species studied during BOREAS. The analyzed data are stored in tabular ASCII files. The data files are available on a CD-ROM (see document number 20010000884), or from the Oak Ridge National Laboratory (ORNL) Distrobuted Activity Archive Center (DAAC).

  2. Approach to nonparametric cooperative multiband segmentation with adaptive threshold.

    PubMed

    Sebari, Imane; He, Dong-Chen

    2009-07-10

    We present a new nonparametric cooperative approach to multiband image segmentation. It is based on cooperation between region-growing segmentation and edge segmentation. This approach requires no input data other than the images to be processed. It uses a spectral homogeneity criterion whose threshold is determined automatically. The threshold is adaptive and varies depending on the objects to be segmented. Applying this new approach to very high resolution satellite imagery has yielded satisfactory results. The approach demonstrated its performance on images of varied complexity and was able to detect objects of great spatial and spectral heterogeneity. PMID:19593349

  3. Engineering the Electronic Band Structure for Multiband Solar Cells

    SciTech Connect

    Lopez, N.; Reichertz, L.A.; Yu, K.M.; Campman, K.; Walukiewicz, W.

    2010-07-12

    Using the unique features of the electronic band structure of GaNxAs1-x alloys, we have designed, fabricated and tested a multiband photovoltaic device. The device demonstrates an optical activity of three energy bands that absorb, and convert into electrical current, the crucial part of the solar spectrum. The performance of the device and measurements of electroluminescence, quantum efficiency and photomodulated reflectivity are analyzed in terms of the Band Anticrossing model of the electronic structure of highly mismatched alloys. The results demonstrate the feasibility of using highly mismatched alloys to engineer the semiconductor energy band structure for specific device applications.

  4. Tunable multiband metasurfaces by moiré nanosphere lithography

    NASA Astrophysics Data System (ADS)

    Wu, Zilong; Chen, Kai; Menz, Ryan; Nagao, Tadaaki; Zheng, Yuebing

    2015-12-01

    Moiré nanosphere lithography (MNSL), which features the relative in-plane rotation between two layers of self-assembled monodisperse nanospheres as masks, provides a cost-effective approach for creating moiré patterns on generic substrates. In this work, we experimentally and numerically investigate a series of moiré metasurfaces by MNSL. Due to the variety of gradient plasmonic nanostructures in arrays, single moiré metasurfaces can support multiple localized surface plasmon (LSP) modes with a wide range of resonant wavelengths from ~600 nm to ~4200 nm. We analyze the origin of the LSP modes based on the optical spectra and near-field electromagnetic distributions. In addition, we fabricate and analyze the metasurfaces with high-density nanogap structures. These nanogap structures support plasmonic gap modes with significant field enhancements. With their tunable multiband optical responses from visible to near-infrared to mid-infrared regimes, these moiré metasurfaces are applicable for ultrabroadband absorbers, multiband surface-enhanced infrared and Raman spectroscopy, and broadband single-molecule spectroscopy.Moiré nanosphere lithography (MNSL), which features the relative in-plane rotation between two layers of self-assembled monodisperse nanospheres as masks, provides a cost-effective approach for creating moiré patterns on generic substrates. In this work, we experimentally and numerically investigate a series of moiré metasurfaces by MNSL. Due to the variety of gradient plasmonic nanostructures in arrays, single moiré metasurfaces can support multiple localized surface plasmon (LSP) modes with a wide range of resonant wavelengths from ~600 nm to ~4200 nm. We analyze the origin of the LSP modes based on the optical spectra and near-field electromagnetic distributions. In addition, we fabricate and analyze the metasurfaces with high-density nanogap structures. These nanogap structures support plasmonic gap modes with significant field enhancements

  5. Precision limits of the twin-beam multiband URSULA

    NASA Technical Reports Server (NTRS)

    Debiase, G. A.; Paterno, L.; Fedel, B.; Santagati, G.; Ventura, R.

    1988-01-01

    URSULA is a multiband astronomical photoelectric photometer which minimizes errors introduced by the presence of the atmosphere. It operates with two identical channels, one for the star to be measured and the other for a reference star. After a technical description of the present version of the apparatus, some measurements of stellar sources of different brightness, and in different atmospheric conditions are presented. These measurements, based on observations made with the 91 cm Cassegrain telescope of the Catania Astrophysical Observatory, are used to check the photometer accuracy and compare its performance with that of standard photometers.

  6. Conversion of sunflower multiband radiometer polarization measurements to polarization parameters

    NASA Technical Reports Server (NTRS)

    Biehl, Larry L.

    1995-01-01

    The data processing analysis and conversion of polarization measurements to polarization parameters from the Sunflower multiband radiometer is presented in this final report. Included is: (1) the actual data analysis; (2) the comparison of the averaging techniques and the percent polarization derived from the original and averaged I, Q, U parameters; (3) the polarizer angles used in conversion; (4) the Matlab files; (5) the relative ground size, field of view location, and view zenith angles, and (6) the summary of all the sky data for all dates.

  7. Nonthermal Radio Emission from Hot Star Winds: Its Origin and Physical Implications

    NASA Technical Reports Server (NTRS)

    Chen, Wan; White, Richard L.

    1994-01-01

    Nonthermal radio emission has been observed from some of the most luminous hot star winds. It is understood to be synchrotron radiation of the relativistic electrons in the winds. To understand how the electrons are accelerated to such high energies and to correctly explain the observed radio flux and spectra require an exhaustive investigation of all the relevant physical processes involved and possibly point to a complex wind structure. In this paper we discuss the logical path toward a comprehensive model of the nonthermal radio emission from hot star winds. Based on the available observational data and fundamental theoretical considerations, we found that the only physically viable and self-consistent scenario is: the nonthermal radio emission is synchrotron radiation of relativistic electrons (left right harpoon) the electrons are accelerated by shocks via the first-order Fermi mechanism (left right harpoon) the acceleration has to be in situ in the radio emitting region (left right harpoon) the shocks formed at the base of the winds have to propagate to beyond the radio photosphere.

  8. Nonthermal radio emission from hot star winds: Its origin and physical implications

    NASA Technical Reports Server (NTRS)

    Chen, Wan; White, Richard L.

    1994-01-01

    Nonthermal radio emission has been observed from some of the most luminous hot star winds. It is understood to be synchrotron radiation of the relativistic electrons in the winds. To understand how the electrons are accelerated to such high energies and to correctly explain the observed radio flux and spectra require an exhaustive investigation of all the relevant physical processes involved and possibly point to a complex wind structure. In this paper we discuss the logical path toward a comprehensive model of the nonthermal radio emission from hot star winds. Based on the available observational data and fundamental theoretical considerations, we found that the only physically viable and self-consistent scenario is: the nonthermal radio emission is synchrotron radiation of relativistic electrons the electrons are accelerated by shocks via the first-order Fermi mechanism the acceleration has to be in situ in the radio emitting region and the shocks formed at the base of the winds have to propagate to beyond the radio photosphere.

  9. Non-thermal Hard X-Ray Emission from Coma and Several Abell Clusters

    SciTech Connect

    Correa, C

    2004-02-05

    We report results of hard X-Ray observations of the clusters Coma, Abell 496, Abell754, Abell 1060, Abell 1367, Abell2256 and Abell3558 using RXTE data from the NASA HEASARC public archive. Specifically we searched for clusters with hard x-ray emission that can be fitted by a power law because this would indicate that the cluster is a source of non-thermal emission. We are assuming the emission mechanism proposed by Vahk Petrosian where the inter cluster space contains clouds of relativistic electrons that by themselves create a magnetic field and emit radio synchrotron radiation. These relativistic electrons Inverse-Compton scatter Microwave Background photons up to hard x-ray energies. The clusters that were found to be sources of non-thermal hard x-rays are Coma, Abell496, Abell754 and Abell 1060.

  10. A Self-Calibrating Multi-Band Region Growing Approach to Segmentation of Single and Multi-Band Images

    SciTech Connect

    Paglieroni, D W

    2002-12-20

    Image segmentation transforms pixel-level information from raw images to a higher level of abstraction in which related pixels are grouped into disjoint spatial regions. Such regions typically correspond to natural or man-made objects or structures, natural variations in land cover, etc. For many image interpretation tasks (such as land use assessment, automatic target cueing, defining relationships between objects, etc.), segmentation can be an important early step. Remotely sensed images (e.g., multi-spectral and hyperspectral images) often contain many spectral bands (i.e., multiple layers of 2D images). Multi-band images are important because they contain more information than single-band images. Objects or natural variations that are readily apparent in certain spectral bands may be invisible in 2D broadband images. In this paper, the classical region growing approach to image segmentation is generalized from single to multi-band images. While it is widely recognized that the quality of image segmentation is affected by which segmentation algorithm is used, this paper shows that algorithm parameter values can have an even more profound effect. A novel self-calibration framework is developed for automatically selecting parameter values that produce segmentations that most closely resemble a calibration edge map (derived separately using a simple edge detector). Although the framework is generic in the sense that it can imbed any core segmentation algorithm, this paper only demonstrates self-calibration with multi-band region growing. The framework is applied to a variety of AVIRIS image blocks at different spectral resolutions, in an effort to assess the impact of spectral resolution on segmentation quality. The image segmentations are assessed quantitatively, and it is shown that segmentation quality does not generally appear to be highly correlated with spectral resolution.

  11. Nonthermal Quantum Channels as a Thermodynamical Resource.

    PubMed

    Navascués, Miguel; García-Pintos, Luis Pedro

    2015-07-01

    Quantum thermodynamics can be understood as a resource theory, whereby thermal states are free and the only allowed operations are unitary transformations commuting with the total Hamiltonian of the system. Previous literature on the subject has just focused on transformations between different state resources, overlooking the fact that quantum operations which do not commute with the total energy also constitute a potentially valuable resource. In this Letter, given a number of nonthermal quantum channels, we study the problem of how to integrate them in a thermal engine so as to distill a maximum amount of work. We find that, in the limit of asymptotically many uses of each channel, the distillable work is an additive function of the considered channels, computable for both finite dimensional quantum operations and bosonic channels. We apply our results to bound the amount of distillable work due to the natural nonthermal processes postulated in the Ghirardi-Rimini-Weber (GRW) collapse model. We find that, although GRW theory predicts the possibility of extracting work from the vacuum at no cost, the power which a collapse engine could, in principle, generate is extremely low. PMID:26182086

  12. Intracranial nonthermal irreversible electroporation: in vivo analysis.

    PubMed

    Garcia, Paulo A; Rossmeisl, John H; Neal, Robert E; Ellis, Thomas L; Olson, John D; Henao-Guerrero, Natalia; Robertson, John; Davalos, Rafael V

    2010-07-01

    Nonthermal irreversible electroporation (NTIRE) is a new minimally invasive technique to treat cancer. It is unique because of its nonthermal mechanism of tumor ablation. Intracranial NTIRE procedures involve placing electrodes into the targeted area of the brain and delivering a series of short but intense electric pulses. The electric pulses induce irreversible structural changes in cell membranes, leading to cell death. We correlated NTIRE lesion volumes in normal brain tissue with electric field distributions from comprehensive numerical models. The electrical conductivity of brain tissue was extrapolated from the measured in vivo data and the numerical models. Using this, we present results on the electric field threshold necessary to induce NTIRE lesions (495-510 V/cm) in canine brain tissue using 90 50-mus pulses at 4 Hz. Furthermore, this preliminary study provides some of the necessary numerical tools for using NTIRE as a brain cancer treatment. We also computed the electrical conductivity of brain tissue from the in vivo data (0.12-0.30 S/m) and provide guidelines for treatment planning and execution. Knowledge of the dynamic electrical conductivity of the tissue and electric field that correlates to lesion volume is crucial to ensure predictable complete NTIRE treatment while minimizing damage to surrounding healthy tissue. PMID:20668843

  13. Nonthermal dark matter models and signals

    NASA Astrophysics Data System (ADS)

    Okada, Hiroshi; Orikasa, Yuta; Toma, Takashi

    2016-03-01

    Many experiments exploring weakly interacting massive particles (WIMPs) such as direct, indirect and collider searches have been carried out until now. However, a clear signal of a WIMP has not been found yet and it makes us to suspect that WIMPs are questionable as a dark matter candidate. Taking into account this situation, we propose two models in which dark matter relic density is produced by decay of a metastable particle. In the first model, the metastable particle is a feebly interacting massive particle, which is the so-called FIMP, produced by freeze-in mechanism in the early universe. In the second model, the decaying particle is thermally produced the same as the usual WIMP. However decay of the particle into dark matter is led by a higher dimensional operator. As a phenomenologically interesting feature of nonthermal dark matter discussed in this paper, a strong sharp gamma-ray emission as an indirect detection signal occurs due to internal bremsstrahlung, although some parameter space has already been ruled out by this process. Moreover combining other experimental and theoretical constraints such as dark matter relic density, big bang nucleosynthesis, collider, gamma-rays and perturbativity of couplings, we discuss the two nonthermal DM models.

  14. Nonthermal Quantum Channels as a Thermodynamical Resource

    NASA Astrophysics Data System (ADS)

    Navascués, Miguel; García-Pintos, Luis Pedro

    2015-07-01

    Quantum thermodynamics can be understood as a resource theory, whereby thermal states are free and the only allowed operations are unitary transformations commuting with the total Hamiltonian of the system. Previous literature on the subject has just focused on transformations between different state resources, overlooking the fact that quantum operations which do not commute with the total energy also constitute a potentially valuable resource. In this Letter, given a number of nonthermal quantum channels, we study the problem of how to integrate them in a thermal engine so as to distill a maximum amount of work. We find that, in the limit of asymptotically many uses of each channel, the distillable work is an additive function of the considered channels, computable for both finite dimensional quantum operations and bosonic channels. We apply our results to bound the amount of distillable work due to the natural nonthermal processes postulated in the Ghirardi-Rimini-Weber (GRW) collapse model. We find that, although GRW theory predicts the possibility of extracting work from the vacuum at no cost, the power which a collapse engine could, in principle, generate is extremely low.

  15. Effective multiband Hamiltonian for InAs in wurtzite phase

    NASA Astrophysics Data System (ADS)

    Faria Junior, Paulo E.; Campos, Tiago; Bastos, Carlos M. O.; Sipahi, Guilherme M.; Gmitra, Martin; Fabian, Jaroslav

    Recent advances in nanostructure growth techniques allowed the synthesis of new III-V compounds with wurtzite crystal structure. Although ab initio band structures for these new wurtzite materials can be found in the literature, we still lack multiband models and parameter sets that can be simply used to investigate, for instance, quantum confinement effects. In this study, we calculated the ab initio band structure of bulk InAs wurtzite and developed a multiband k.p Hamiltonian to describe the energy bands around the energy gap. In order to correctly describe the spin splitting effects we included the k-dependent spin-orbit term, often neglected in literature. We showed that our model is very robust to describe the important features of the band structure and also the spin splittings with great agreement to the ab initio values. CNPq (149904/2013­-4 and 88887.110814/2015-00), CAPES PVE (88881.068174/2014-01), DFG SFB 689 and FAPESP (2012/05618-0).

  16. 3D Display Using Conjugated Multiband Bandpass Filters

    NASA Technical Reports Server (NTRS)

    Bae, Youngsam; White, Victor E.; Shcheglov, Kirill

    2012-01-01

    Stereoscopic display techniques are based on the principle of displaying two views, with a slightly different perspective, in such a way that the left eye views only by the left eye, and the right eye views only by the right eye. However, one of the major challenges in optical devices is crosstalk between the two channels. Crosstalk is due to the optical devices not completely blocking the wrong-side image, so the left eye sees a little bit of the right image and the right eye sees a little bit of the left image. This results in eyestrain and headaches. A pair of interference filters worn as an optical device can solve the problem. The device consists of a pair of multiband bandpass filters that are conjugated. The term "conjugated" describes the passband regions of one filter not overlapping with those of the other, but the regions are interdigitated. Along with the glasses, a 3D display produces colors composed of primary colors (basis for producing colors) having the spectral bands the same as the passbands of the filters. More specifically, the primary colors producing one viewpoint will be made up of the passbands of one filter, and those of the other viewpoint will be made up of the passbands of the conjugated filter. Thus, the primary colors of one filter would be seen by the eye that has the matching multiband filter. The inherent characteristic of the interference filter will allow little or no transmission of the wrong side of the stereoscopic images.

  17. Quantum funneling in blended multi-band gap core/shell colloidal quantum dot solar cells

    SciTech Connect

    Neo, Darren C. J.; Assender, Hazel E.; Watt, Andrew A. R.; Stranks, Samuel D.; Eperon, Giles E.; Snaith, Henry J.

    2015-09-07

    Multi-band gap heterojunction solar cells fabricated from a blend of 1.2 eV and 1.4 eV PbS colloidal quantum dots (CQDs) show poor device performance due to non-radiative recombination. To overcome this, a CdS shell is epitaxially formed around the PbS core using cation exchange. From steady state and transient photoluminescence measurements, we understand the nature of charge transfer between these quantum dots. Photoluminescence decay lifetimes are much longer in the PbS/CdS core/shell blend compared to PbS only, explained by a reduction in non-radiative recombination resulting from CdS surface passivation. PbS/CdS heterojunction devices sustain a higher open-circuit voltage and lower reverse saturation current as compared to PbS-only devices, implying lower recombination rates. Further device performance enhancement is attained by modifying the composition profile of the CQD species in the absorbing layer resulting in a three dimensional quantum cascade structure.

  18. The simulation and analysis of infrared target multi-band characteristics

    NASA Astrophysics Data System (ADS)

    Cui, Lanfang; Zhou, Jinmei

    2014-09-01

    The infrared characteristic simulation of the target is the basis of true and false infrared target recognition. With the development of stealth technology, imaging features of the decoy in the detector are more and more close to the real target, so it is not easy to distinguish between the target and decoy by using information acquired from single-band infrared detector. Based on this, in the paper infrared imaging properties of the target in a number of bands are simulated and analyzed, followed by fusing the characteristic differences of multiple bands between true and false target for classification and recognition. First of all, we construct the geometrical model of target and decoy in a simple background, and then the model of infrared radiation is built. What is more, in accordance with laws of infrared radiation and other relevant laws, the characteristics of target and decoy under the condition of different bands are analyzed. Experimental results show that the proposed multi-band target simulation and analysis method can effectively identify the target and decoy in the same field of view.

  19. Motion of 3-6 keV Nonthermal Sources Along the Legs of a Flare Loop

    NASA Technical Reports Server (NTRS)

    Sui, Linhui; Holman, Gordon D.; Dennis, Brian R.

    2007-01-01

    Observations of nonthermal X-ray sources me critical to studying electron acceleration and transport in solar flares. Strong thermal emission radiated from the preheated plasma before the flare impulsive phase often makes it difficult to detect low-energy X-ray sources that are produced by relatively low-energy nonthermal electrons. Knowledge of the distribution of these low-energy nonthermal electrons is particularly important in determining the total nonthermal electron energy in solar flares. We report on an 'early impulsive flare' in which impulsive hard X-ray emission was seen early in the flare before the soft X-ray emission had risen significantly, indicating limited plasma pre-heating. Early in the flare, RHESSI < 25 keV images show coronal sources that moved first downward and then upwards along the legs of a flare loop. In particular, the 3-6 keV source appeared as a single coronal source at the start of the flare, and then it involved into two coronal sources moving down along the two legs of the loop. After nearly reaching the two footpoints at the hard X-ray peak, the two sources moved back up to the looptop again. RHESSI images and light curves all indicate that nonthermal emission dominated at energies as low as 3-6 keV. We suggest that the evolution of both the spectral index and the low-energy cutoff of the injected electron distribution could result in the accelerated electrons reaching a lower altitude along the legs of the dense flare loop and hence result in the observed downward and upward motions of the nonthermal sources.

  20. MgB2: Novel properties due to multibands

    NASA Astrophysics Data System (ADS)

    Blumberg, Girsh

    2008-03-01

    About 40 years ago A.J. Leggett proposed a new collective mode arising from cross-tunneling of Cooper pairs residing on different Fermi surfaces of a multiband superconductor: Leggett's collective mode is caused by a counter flow of the interacting superfluids leading to small fluctuations of the relative phase of the condensates while the total electron density is locally conserved.ootnotetextA.J. Leggett, Progr. Theor. Phys. 36, 901 (1966). Here we present direct spectroscopic observation of the Leggett's excitation in the MgB2 superconductor containig two pairs of Fermi surfaces resulting from π- and σ-bands. Electronic Raman scattering studies have revealed three distinct superconducting (SC) features: (i) a clean threshold of Raman intensity at 4.6 meV consistent with the π-band SC gap; (ii) the SC pair breaking coherence peak at 13.5 meV consistent with excitations above the σ-band gap; and (iii) the SC collective mode at 9.4 meV which we assign to an excitation first discussed by Leggett.ootnotetextG. Blumberg et al., Phys. Rev. Lett. 99 (2007); arXiv:0710.2803http://arxiv.org/pdf/0710.2803. Our calculation of the Raman response function for MgB2 superconductor based on multiband interaction matrices by first principle computations show good agreement with spectroscopic observations. The temperature and field dependencies for all three features (i) -- (iii) have been established;ootnotetextG. Blumberg et al., Physica (Amsterdam) 456C, 75 (2007). the effects of magnetic field on the pair cross-tunneling in multiband system will be discussed. In addition, anharmonicity and superconductivity-induced self-energy effects for the E2g boron stretching phonon have been studied.ootnotetextA. Mialitsin et al., Phys. Rev. B 75, 020509(R) (2007). We show that anharmonic two-phonon decay is mainly responsible for the unusually large linewidth of the E2g mode. We observe 2.5% hardening of the E2g phonon frequency upon cooling into the SC state and estimate the

  1. Electronic correlation effects in multi-band systems

    NASA Astrophysics Data System (ADS)

    Song, Kok Wee

    The recent dominant trends in condensed matter physics research can be roughly summarized into three newly discovered materials: topological insulators, graphene, and iron-based superconductors. All these materials exhibit many intriguing properties which are fundamentally related to their electronic band structure. Therefore, this lead to many intense investigations on multi-band electronic system to explore new physics. The physics of multi-band electronic structure is fascinating in several aspects. Without many-body effects, because of the gauge freedom of Bloch states, topological insulators can give rise a robust metallic behavior at its boundaries. In graphene, the touching between conduction and valence band at Fermi level yields a new criticality class which exhibit many unconventional electronic properties, especially its quasi-relativistic behavior. Turning to the many-body effects, for instance, the iron-based superconductors can sustain an superconducting ground state despite of no attractive interactions in the system. Therefore, a deeper understanding for the conventional notions in condensed matter physics has put forward by many of these experimental observations. In this thesis, the many-body effects in multi-band systems are the main focus, especially the study of graphene and iron-based superconductors which can be compared to experiments. These theoretical studies intend to understand how the underlying electronic bands degree of freedom can give rise to Fermi-liquid instabilities, and how these effects can be related to intriguing physical properties. We first study the electrons correlation effects in bilayer graphene by a renormalization group technique. In this study, we build a microscopic model of bilayer graphene from a tight-binding approach. In our finding, the peculiar Fermi surface configuration leads to critical behavior which is beyond the Fermi-liquid paradigm. Furthermore, due to the electron-electron interactions between

  2. Nonthermal galactic emission below 10 MHz

    NASA Technical Reports Server (NTRS)

    Novaco, J. C.; Brown, L. W.

    1977-01-01

    The Radio Astronomy Explorer-2 (RAE-2) satellite has provided new measurements of the nonthermal galactic radio emission at frequencies below 10 MHz. Measurements of the emission spectra are presented for the center, anticenter, north polar, and south polar directions at 22 frequencies between 0.25 and 9.18 MHz. Survey maps of the spatial distribution of the observed low frequency galactic emission at 1.31, 2.20, 3.93, 4.70, 6.55, and 9.18 MHz are presented. The observations were obtained with the 229-meter traveling-wave V-antenna on this lunar orbiting spacecraft. The improved frequency coverage offers additional insights into structure of the local galactic neighborhood.

  3. Modelling of Nonthermal Microwave Emission from Twisted Magnetic Loops

    NASA Astrophysics Data System (ADS)

    Sharykin, I. N.; Kuznetsov, A. A.

    2016-05-01

    Microwave gyrosynchrotron radio emission generated by nonthermal electrons in twisted magnetic loops is modelled using the recently developed simulation tool GX Simulator. We consider isotropic and anisotropic pitch-angle distributions. The main scope of the work is to understand the impact of a twisted magnetic field topology on radio emission maps. We have found that nonthermal electrons inside twisted magnetic loops produce gyrosynchrotron radio emission with a particular polarisation distribution. The polarisation sign inversion line is inclined relatively to the axis of the loop. The radio emission source is more compact in the case of a less twisted loop, assuming an anisotropic pitch-angle distribution of nonthermal electrons.

  4. Modelling of Nonthermal Microwave Emission from Twisted Magnetic Loops

    NASA Astrophysics Data System (ADS)

    Sharykin, I. N.; Kuznetsov, A. A.

    2016-06-01

    Microwave gyrosynchrotron radio emission generated by nonthermal electrons in twisted magnetic loops is modelled using the recently developed simulation tool GX Simulator. We consider isotropic and anisotropic pitch-angle distributions. The main scope of the work is to understand the impact of a twisted magnetic field topology on radio emission maps. We have found that nonthermal electrons inside twisted magnetic loops produce gyrosynchrotron radio emission with a particular polarisation distribution. The polarisation sign inversion line is inclined relatively to the axis of the loop. The radio emission source is more compact in the case of a less twisted loop, assuming an anisotropic pitch-angle distribution of nonthermal electrons.

  5. Optically addressed near and long-wave infrared multiband photodetectors

    NASA Astrophysics Data System (ADS)

    Cellek, O. O.; Reno, J. L.; Zhang, Y.-H.

    2012-06-01

    Optically addressed dual-band photodetector incorporating of a 0.82 μm cut-off wavelength near-infrared (NIR) AlGaAs/GaAs p-i-n photodetector and a 8.2 μm peak wavelength long-wave infrared (LWIR) AlGaAs/GaAs quantum well infrared photodetector on GaAs substrate is fabricated and characterized. Switching between NIR and LWIR bands is demonstrated by using external light bias. The dual-band photodetector gives 65% quantum efficiency in NIR band and specific detectivity of 2 × 109cm Hz1/2/W in LWIR band at 68 K. Spectral crosstalk is better than 25 dB. These devices enable the use of only a single indium-bump per pixel for multiband image sensor arrays to have maximum fill factor.

  6. Traffic placement policies for a multi-band network

    NASA Technical Reports Server (NTRS)

    Maly, Kurt J.; Foudriat, E. C.; Game, David; Mukkamala, R.; Overstreet, C. Michael

    1990-01-01

    Recently protocols were introduced that enable the integration of synchronous traffic (voice or video) and asynchronous traffic (data) and extend the size of local area networks without loss in speed or capacity. One of these is DRAMA, a multiband protocol based on broadband technology. It provides dynamic allocation of bandwidth among clusters of nodes in the total network. A number of traffic placement policies for such networks are proposed and evaluated. Metrics used for performance evaluation include average network access delay, degree of fairness of access among the nodes, and network throughput. The feasibility of the DRAMA protocol is established through simulation studies. DRAMA provides effective integration of synchronous and asychronous traffic due to its ability to separate traffic types. Under the suggested traffic placement policies, the DRAMA protocol is shown to handle diverse loads, mixes of traffic types, and numbers of nodes, as well as modifications to the network structure and momentary traffic overloads.

  7. Atmospheric pressure nonthermal plasmas for bacterial biofilm prevention and eradication.

    PubMed

    Ermolaeva, Svetlana A; Sysolyatina, Elena V; Gintsburg, Alexander L

    2015-01-01

    Biofilms are three-dimensional structures formed by surface-attached microorganisms and their extracellular products. Biofilms formed by pathogenic microorganisms play an important role in human diseases. Higher resistance to antimicrobial agents and changes in microbial physiology make treating biofilm infections very complex. Atmospheric pressure nonthermal plasmas (NTPs) are a novel and powerful tool for antimicrobial treatment. The microbicidal activity of NTPs has an unspecific character due to the synergetic actions of bioactive components of the plasma torch, including charged particles, reactive species, and UV radiation. This review focuses on specific traits of biofilms, their role in human diseases, and those effects of NTP that are helpful for treating biofilm infections. The authors discuss NTP-based strategies for biofilm control, such as surface modifications to prevent bacterial adhesion, killing bacteria in biofilms, and biofilm destruction with NTPs. The unspecific character of microbicidal activity, proven polymer modification and destruction abilities, low toxicity for human tissues and absence of long-living toxic compounds make NTPs a very promising tool for biofilm prevention and control. PMID:25869456

  8. Multiband superconductivity in Lu3Os4Ge13

    NASA Astrophysics Data System (ADS)

    Prakash, Om; Thamizhavel, A.; Ramakrishnan, S.

    2015-11-01

    Intermetallic R3T4X13 series consist of a cage-like structure and have attracted attention due to their unconventional electronic ground states. In this work, we report the normal and superconducting state properties of a high-quality single crystal of Lu3Os4Ge13. Lu3Os4Ge13 belongs to the above-mentioned series and crystallizes in a cubic crystal structure with the space group {\\text{}}{Pm}\\bar{3}n. Using electrical transport, magnetization and heat capacity measurements, we show that Lu3Os4Ge13 is a type-II multi-band superconductor (T c = 3.1 K) with unusual superconducting properties. The analysis of the low-temperature heat capacity data suggests that Lu3Os4Ge13 is a moderately coupled multi-band BCS superconductor with two gaps (2{{Δ }}/{k}B{T}c=3.68+/- 0.04\\\\&\\0.34+/- 0.02) in the superconducting state. The dc-magnetization (M-H) shows a large reversible region in the superconducting state similar to the vortex liquid phase observed in high-T c superconductors. The value of the Ginzburg number G i suggests that the thermal fluctuations, though small compared to those in high-T c cuprates, may play an important role in the unpinning of the vortices in this compound. The electronic band structure calculations show that three bands cross the Fermi level and constitute a complex Fermi surface in Lu3Os4Ge13.

  9. DUST DESTRUCTION IN A NON-RADIATIVE SHOCK IN THE CYGNUS LOOP SUPERNOVA REMNANT

    SciTech Connect

    Sankrit, Ravi; Gaetz, Terrance J.; Raymond, John C.; Blair, William P.; Ghavamian, Parviz; Long, Knox S.

    2010-04-01

    We present 24 {mu}m and 70 {mu}m images of a non-radiative shock in the Cygnus Loop supernova remnant, obtained with the Multiband Imaging Photometer for Spitzer on board the Spitzer Space Telescope. The post-shock region is resolved in these images. The ratio of the 70 {mu}m to the 24 {mu}m flux rises from about 14 at a distance 0.'1 behind the shock front to about 22 in a zone 0.'75 further downstream, as grains are destroyed in the hot plasma. Models of dust emission and destruction using post-shock electron temperatures between 0.15 keV and 0.30 keV and post-shock densities, n{sub H}{approx} 2.0 cm{sup -3}, predict flux ratios that match the observations. Non-thermal sputtering (i.e., sputtering due to bulk motion of the grains relative to the gas) contributes significantly to the dust destruction under these shock conditions. From the model calculations, we infer that about 35% by mass of the grains are destroyed over a 0.14 pc region behind the shock front.

  10. An evaluation of multiband photography for rock discrimination. [sedimentary rocks of Front Range, Colorado

    NASA Technical Reports Server (NTRS)

    Lee, K. (Principal Investigator); Raines, G. L.

    1974-01-01

    The author has identified the following significant results. With the advent of ERTS and Skylab satellites, multiband imagery and photography have become readily available to geologists. The ability of multiband photography to discriminate sedimentary rocks was examined. More than 8600 in situ measurements of band reflectance of the sedimentary rocks of the Front Range, Colorado, were acquired. Statistical analysis of these measurements showed that: (1) measurements from one site can be used at another site 100 miles away; (2) there is basically only one spectral reflectance curve for these rocks, with constant amplitude differences between the curves; and (3) the natural variation is so large that at least 150 measurements per formation are required to select best filters. These conclusions are supported by subjective tests with aerial multiband photography. The designed multiband photography concept for rock discrimination is not a practical method of improving sedimentary rock discrimination capabilities.

  11. Tomographic analysis of the nonthermal x-ray bursts during disruption instability in the T-10 tokamak

    NASA Astrophysics Data System (ADS)

    Savrukhin, P. V.; Ermolaeva, A. I.; Shestakov, E. A.; Khramenkov, A. V.

    2014-10-01

    Non-thermal x-ray radiation (Eγ up to 150 keV) is measured in the T-10 tokamaks during disruption instability using two sets of CdTe detectors (10 vertical and 7 horizontal view detectors). Special narrow cupper tubes collimators with lead screening and CdTe detectors integrated with amplifiers inside metallic containers provides enhanced spatial resolution of the system (r ˜ 3 cm) and assures protection from the parasitic hard x-ray (Eγ up to 1.5 MeV) and electromagnetic loads during disruption. Spatial localization of the nonthermal x-ray emissivity is reconstructed using tomographic Cormack technique with SVD matrix inversion. Analysis indicated appearance of an intensive non-thermal x-ray bursts during initial stage of the disruptions at high density. The bursts are characterized by repetitive spikes (2-3 kHz) of the x-ray emissivity from the plasma core area. Analysis indicated that the spikes can be connected with acceleration of the non-thermal electrons in enhanced longitudinal electric fields induced during energy quench at the disruption instability.

  12. Tomographic analysis of the nonthermal x-ray bursts during disruption instability in the T-10 tokamak

    SciTech Connect

    Savrukhin, P. V.; Ermolaeva, A. I.; Shestakov, E. A.; Khramenkov, A. V.

    2014-10-01

    Non-thermal x-ray radiation (E{sub γ} up to 150 keV) is measured in the T-10 tokamaks during disruption instability using two sets of CdTe detectors (10 vertical and 7 horizontal view detectors). Special narrow cupper tubes collimators with lead screening and CdTe detectors integrated with amplifiers inside metallic containers provides enhanced spatial resolution of the system (r ~ 3 cm) and assures protection from the parasitic hard x-ray (E{sub γ} up to 1.5 MeV) and electromagnetic loads during disruption. Spatial localization of the nonthermal x-ray emissivity is reconstructed using tomographic Cormack technique with SVD matrix inversion. Analysis indicated appearance of an intensive non-thermal x-ray bursts during initial stage of the disruptions at high density. The bursts are characterized by repetitive spikes (2–3 kHz) of the x-ray emissivity from the plasma core area. Analysis indicated that the spikes can be connected with acceleration of the non-thermal electrons in enhanced longitudinal electric fields induced during energy quench at the disruption instability.

  13. Non-thermal processes during the 'build-up' phase of solar flares and in absence of flares

    NASA Technical Reports Server (NTRS)

    Kane, S. R.; Pick, M.

    1976-01-01

    Hard X-ray and radio observations indicate production of non-thermal electrons as a common phenomenon of the active sun. A preliminary analysis of three hard X-ray bursts observed with the OGO-5 satellite and radio observations indicate that non-thermal particles are present in the flare region prior to the impulsive (flash) phase and also during the gradual rise and fall (GRF) bursts which are usually explained in terms of purely 'thermal' radiation. The principal difference between the non-thermal electrons observed before the flash phase and during the flash phase appears to be in their total number rather than in the hardness of their energy spectrum. Basic characteristics of the two acceleration processes are probably similar although the total energy converted into non-thermal electrons is considerably larger in the flash phase. Transient absorbing H-alpha features and filament activations are discussed in terms of their ability to produce energetic particle events and magnetic energy release.

  14. Tomographic analysis of the nonthermal x-ray bursts during disruption instability in the T-10 tokamak.

    PubMed

    Savrukhin, P V; Ermolaeva, A I; Shestakov, E A; Khramenkov, A V

    2014-10-01

    Non-thermal x-ray radiation (Eγ up to 150 keV) is measured in the T-10 tokamaks during disruption instability using two sets of CdTe detectors (10 vertical and 7 horizontal view detectors). Special narrow cupper tubes collimators with lead screening and CdTe detectors integrated with amplifiers inside metallic containers provides enhanced spatial resolution of the system (r ∼ 3 cm) and assures protection from the parasitic hard x-ray (Eγ up to 1.5 MeV) and electromagnetic loads during disruption. Spatial localization of the nonthermal x-ray emissivity is reconstructed using tomographic Cormack technique with SVD matrix inversion. Analysis indicated appearance of an intensive non-thermal x-ray bursts during initial stage of the disruptions at high density. The bursts are characterized by repetitive spikes (2-3 kHz) of the x-ray emissivity from the plasma core area. Analysis indicated that the spikes can be connected with acceleration of the non-thermal electrons in enhanced longitudinal electric fields induced during energy quench at the disruption instability. PMID:25362394

  15. Structure of proton centers and associated nonthermal bursts at microwave frequencies

    NASA Technical Reports Server (NTRS)

    Enome, S.; Tanaka, H.

    1973-01-01

    A very broad band of electromagnetic radiation is emitted during solar flares, especially at the explosive phase. The existence of a large variety of plasmas with various densities and a wide range of temperatures or energies is proposed as the initiating agent. The manner in which the plasmas are heated and accelerated to subrelativistic and relativistic energies is discussed. Observational evidence on the characteristics of active regions which produced proton flares and on the structure of the associated nonthermal microwave bursts of the sun is presented. The behavior of subrelativistic electrons on the sun is described.

  16. PROBING SHOCK PROPERTIES WITH NONTHERMAL X-RAY FILAMENTS IN CAS A

    SciTech Connect

    Araya, Miguel; Lomiashvili, David; Chang, Chulhoon; Lyutikov, Maxim; Cui Wei E-mail: dlomiash@purdue.ed E-mail: lyutikov@purdue.ed

    2010-05-01

    Thin nonthermal X-ray filaments are often seen in young supernova remnants. We used data from the 1 Ms Chandra observation of Cassiopeia A to study spectral properties of some of the filaments in this remnant. For all the cases that we examined, the X-ray spectrum across the filaments hardens, at about 10% level, going outward, while observed filament widths depend only weakly on the photon energy. Using a model that includes radiative cooling, advection, and diffusion of accelerated particles behind the shock, we estimated the magnetic field, turbulence level, and shock obliquity.

  17. Design of a planar multiband Sierpinski E-shaped carpet antenna with CPW fed for multi standard wireless terminals

    NASA Astrophysics Data System (ADS)

    Sahu, K. Satyabrat; Panda, Asit K.

    2013-01-01

    In this paper Sierpinski E-Carpet antenna based on the implementation of fractal technique is proposed for multiband applications in 2-10 GHz band. There appeared 5 resonant frequencies at 2.35 GHz, 3.5 GHz, 5.503 GHz, 7.248GHz, and 8.79GHz for 2nd iteration. From the return loss plot it is seen that antenna achieved the IEEE Bluetooth/WLAN (2.4-2.484 GHz), WiMAX (3.4-3.69 GHz) and WIFI (5.1-5.825 GHz) frequency band with -10dB return loss. Also nearly omni-directional radiation pattern is observed. A prototype of the design is successfully implemented with close agreement between measurement and simulation result.

  18. Preradiation studies for non-thermal Z-pinch wire load experiments on Saturn

    SciTech Connect

    Sanford, T.W.L.; Humphreys, D.R.; Poukey, J.W.; Marder, B.M.; Halbleib, J.A.; Crow, J.T.; Spielman, R.B.; Mock, R.C.

    1994-06-01

    The implosion dynamics of compact wire arrays on Saturn are explored as a function of wire mass m, wire length {ell}, wire radii R, and radial power-flow feed geometry using the ZORK code. Electron losses and the likelihood of arcing in the radial feed adjacent the wire load are analyzed using the TWOQUICK and CYLTRAN codes. The physical characteristics of the implosion and subsequent thermal radiation production are estimated using the LASNEX code in one dimension. These analyses show that compact tungsten wire arrays with parameters suggested by D. Mosher and with a 21-nH vacuum feed geometry satisfy the empirical scaling criterion I/(M/{ell}) {approximately} 2 MA/(mg/cm) of Mosher for optimizing non-thermal radiation from z pinches, generate low electron losses in the radial feeds, and generate electric fields at the insulator stack below the Charlie Martin flashover limit thereby permitting full power to be delivered to the load. Under such conditions, peak currents of {approximately}5 MA can be delivered to wire loads {approximately}20 ns before the driving voltage reverses at the insulator stack, potentially allowing the m = 0 instability to develop with the subsequent emission of non-thermal radiation as predicted by the Mosher model.

  19. Comment on "Non-thermal mechanism of weak microwave fields influence on neurons" [J. Appl. Phys. 114, 104701 (2013)

    NASA Astrophysics Data System (ADS)

    Pekker, M.; Shneider, M. N.

    2016-02-01

    This comment is directly related to previously published work [M. N. Shneider and M. Pekker, J. Appl. Phys. 114, 104701 (2013)], in which we outlined the effect of a non-thermal mechanism of microwave radiation on the activity of neural tissue. In this note, we provide more realistic estimates of the longitudinal sound velocity in the lipid membranes and the corresponding estimates of the microwave resonance frequencies.

  20. Observations of nonthermal radiation from late-type stars

    SciTech Connect

    Bookbinder, J.A.

    1985-01-01

    Statistical properties of the x-ray and radioemission from the coronae of a sample of late-type stars were studied. The sample consisted of a large, nearly volume-limited, population of K and M dwarfs. From the analyses, conclusions are drawn regarding stellar dynamos, evolution of low-mass binary systems, and the nature of the coronal heating mechanism in low-mass stars. Statistical behavior of the x-ray emission from the complete Einstein survey 243 late-type stars within 25 pc is first examined, focusing on the stellar age and color dependences. Optically selected, nearly volume limited subsamples reasonably free of known biases are used to show that, relative to the young disk stars, old disk stars have levels of coronal emission almost an order of magnitude smaller. There is also a steady, but small, decrease of coronal activity with decreasing mass. A subset of these stars present in the x-ray survey was selected for observations of radio wavelengths. Combined with previously reported radio observations of M dwarfs and the x-ray data, it is shown that these observations can provide a new characterization of the coronal activity of late-type stars.

  1. Electron Cyclotron Emission from Nonthermal Distributions

    NASA Astrophysics Data System (ADS)

    Harvey, R. W.; Coda, S.; Taylor, G.; Austin, M. E.; Prater, R.

    2005-10-01

    The GENRAY ray tracing code incorporates a solution of the RF energy transport equation (emission and absorption along WKB rays) including the effects of nonthermal electron distribution functions. Distributions are from self-consistent RF solutions of the bounce-averaged Fokker-Planck equation using the CQL3D 2V-1R code. We present computed spectra for two experimental situations: (1) EBW emission from electron distributions in NSTX due to future EBWCD experiments. In this case, the calculated transport of the EBW emission from overdense (omega/pe > omega/ce) NSTX plasma to the plasma edge accounts for the effects of BXO mode conversion whereby EBW waves transform to X-mode, then O-mode near the omega/pe=1 surface; and (2) EC emission in present low density DIII-D ECH experiments. A 27 keV central ECE temperature is calculated, in close agreement with the experimental value, for a plasma with 6.5 keV Thomson scattering temperature. Acknowledgment: USDOE Grants DE-AC03-99ER54463 and DE-FG03-02ER54684, and CRPP-EPFL.

  2. Nonthermal Atmospheric Plasmas in Dental Restoration.

    PubMed

    Liu, Y; Liu, Q; Yu, Q S; Wang, Y

    2016-05-01

    It is well known that the service life of contemporary composite restoration is unsatisfactory, and longevity of dentin bonding is one of the major culprits. Bonding is essentially a hybridization process in which dental substrate and adhesive resin interact with each other through an exchange process. Thus, the longevity of dentin bonding can only be improved with enhanced qualities in substrate, adhesive resin, and their interaction within the hybridization zone. This review aims to collect and summarize recent advances in utilizing nonthermal atmospheric plasmas (NTAPs)-a novel technology that delivers highly reactive species in a gaseous medium at or below physiologic temperature-to improve the durability of dentin bonding by addressing these 3 issues simultaneously. Overall, NTAP has demonstrated efficacies in improving a number of critical properties for dentin bonding, including deactivation of oral pathogens, modification of surface chemistry/properties, resin polymerization, improvement in adhesive-dentin interactions, and establishment of auxiliary bonding mechanism. While a few preliminary studies have indicated the benefit of NTAP to bond strength and stability, additional researches are warranted to employ knowledge acquired so far and to evaluate these properties in a systematic way. PMID:26848068

  3. Nonthermal dark matter from cosmic strings

    SciTech Connect

    Cui Yanou; Morrissey, David E.

    2009-04-15

    Cosmic strings can be created in the early universe during symmetry-breaking phase transitions, such as might arise if the gauge structure of the standard model is extended by additional U(1) factors at high energies. Cosmic strings presented in the early universe form a network of long horizon-length segments, as well as a population of closed string loops. The closed loops are unstable against decay, and can be a source of nonthermal particle production. In this work we compute the density of weakly-interacting massive particle dark matter formed by the decay of gauge theory cosmic string loops derived from a network of long strings in the scaling regime or under the influence of frictional forces. We find that for symmetry-breaking scales larger than 10{sup 10} GeV, this mechanism has the potential to account for the observed relic density of dark matter. For symmetry-breaking scales lower than this, the density of dark matter created by loop decays from a scaling string network lies below the observed value. In particular, the cosmic strings originating from a U(1) gauge symmetry broken near the electroweak scale, that could lead to a massive Z{sup '} gauge boson observable at the LHC, produces a negligibly small dark matter relic density by this mechanism.

  4. Nonthermal Processes in the ISM and ICM

    NASA Astrophysics Data System (ADS)

    Peng Oh, Siang

    The ISM and ICM are both multiphase plasmas where non-thermal components in the form of B-fields, cosmic rays and turbulence play a critical role in numerous physical processes. For instance, B-fields result in anisotropic heat and momentum transport, cosmic-rays heat and pressurize the gas, and turbulence transport heat, metals and (in the ISM) is critical for seeding star formation. This proposal leverages overlap in physical scenarios in the ISM and ICM to fuel progress. We will: (i) study cosmic-ray heating in a multi-phase gas, which can potentially affect heating high above the galactic plane and the survival of cold clumps in a cosmic-ray driven galactic wind; (ii) simulate the abundance and spectral characteristics of fossil and secondary cosmic ray electrons which generate giant radio halos once re-accelerated; (iii) study hydrogen Lyman-alpha scattering in a turbulent, optically thick medium with a finite velocity correlation length, and build models to interpret observations of high-redshift galaxies; (iv) run MHD simulations of the interaction between turbulence and shocks in cluster radio relics, and implications for the geometry and amplification of postshock magnetic fields.

  5. Evolution of streamer groups in nonthermal plasma

    SciTech Connect

    Okubo, M.

    2015-12-15

    Nonthermal plasmas (NTPs) induced by atmospheric nanosecond pulsed corona discharge have been studied for controlling pollution from combustors, such as boilers, incinerators, and diesel engines. In high-speed short-width high-voltage pulsed corona discharge-induced plasmas, primary streamer evolution is followed by secondary streamer evolution. Though this phenomenon is known experimentally, the details of the structures of the streamers and their evolution mechanisms have not been fully clarified. In this letter, we perform quasi two-dimensional numerical analysis of nonequilibrium NTP induced by a nanosecond positive pulsed corona discharge. The continuum fluid equations for two-temperature nonequilibrium NTP are used as governing equations. In this study, 197 gas phase reactions for 25 chemical species and 21 surface reactions on the inner glass wall surface are considered in an air plasma under atmospheric pressure. The simulated behavior of the streamer groups agrees with experimental observations. Soon after the voltage increases on the reactor, primary streamers are formed, which may transit the complete gap, disappearing near the peak voltage. Next, second streamers appear, disappearing at the end of the applied voltage pulse. The streamer wavelength and the distance between the streamers in the axial direction are determined. Moreover, ozone generation is shown to be more significant in the secondary streamer. This simulation will allow better predictions for nanosecond positive pulsed plasma systems.

  6. Evolution of streamer groups in nonthermal plasma

    NASA Astrophysics Data System (ADS)

    Okubo, M.

    2015-12-01

    Nonthermal plasmas (NTPs) induced by atmospheric nanosecond pulsed corona discharge have been studied for controlling pollution from combustors, such as boilers, incinerators, and diesel engines. In high-speed short-width high-voltage pulsed corona discharge-induced plasmas, primary streamer evolution is followed by secondary streamer evolution. Though this phenomenon is known experimentally, the details of the structures of the streamers and their evolution mechanisms have not been fully clarified. In this letter, we perform quasi two-dimensional numerical analysis of nonequilibrium NTP induced by a nanosecond positive pulsed corona discharge. The continuum fluid equations for two-temperature nonequilibrium NTP are used as governing equations. In this study, 197 gas phase reactions for 25 chemical species and 21 surface reactions on the inner glass wall surface are considered in an air plasma under atmospheric pressure. The simulated behavior of the streamer groups agrees with experimental observations. Soon after the voltage increases on the reactor, primary streamers are formed, which may transit the complete gap, disappearing near the peak voltage. Next, second streamers appear, disappearing at the end of the applied voltage pulse. The streamer wavelength and the distance between the streamers in the axial direction are determined. Moreover, ozone generation is shown to be more significant in the secondary streamer. This simulation will allow better predictions for nanosecond positive pulsed plasma systems.

  7. Nonthermal-plasma-mediated animal cell death

    NASA Astrophysics Data System (ADS)

    Kim, Wanil; Woo, Kyung-Chul; Kim, Gyoo-Cheon; Kim, Kyong-Tai

    2011-01-01

    Animal cell death comprising necrosis and apoptosis occurred in a well-regulated manner upon specific stimuli. The physiological meanings and detailed molecular mechanisms of cell death have been continuously investigated over several decades. Necrotic cell death has typical morphological changes, such as cell swelling and cell lysis followed by DNA degradation, whereas apoptosis shows blebbing formation and regular DNA fragmentation. Cell death is usually adopted to terminate cancer cells in vivo. The current strategies against tumour are based on the induction of cell death by adopting various methods, including radiotherapy and chemotherapeutics. Among these, radiotherapy is the most frequently used treatment method, but it still has obvious limitations. Recent studies have suggested that the use of nonthermal air plasma can be a prominent method for inducing cancer cell death. Plasma-irradiated cells showed the loss of genomic integrity, mitochondrial dysfunction, plasma membrane damage, etc. Tumour elimination with plasma irradiation is an emerging concept in cancer therapy and can be accelerated by targeting certain tumour-specific proteins with gold nanoparticles. Here, some recent developments are described so that the mechanisms related to plasma-mediated cell death and its perspectives in cancer treatment can be understood.

  8. Silicon drift detector based X-ray spectroscopy diagnostic system for the study of non-thermal electrons at Aditya tokamak.

    PubMed

    Purohit, S; Joisa, Y S; Raval, J V; Ghosh, J; Tanna, R; Shukla, B K; Bhatt, S B

    2014-11-01

    Silicon drift detector based X-ray spectrometer diagnostic was developed to study the non-thermal electron for Aditya tokamak plasma. The diagnostic was mounted on a radial mid plane port at the Aditya. The objective of diagnostic includes the estimation of the non-thermal electron temperature for the ohmically heated plasma. Bi-Maxwellian plasma model was adopted for the temperature estimation. Along with that the study of high Z impurity line radiation from the ECR pre-ionization experiments was also aimed. The performance and first experimental results from the new X-ray spectrometer system are presented. PMID:25430326

  9. Silicon drift detector based X-ray spectroscopy diagnostic system for the study of non-thermal electrons at Aditya tokamak

    SciTech Connect

    Purohit, S. Joisa, Y. S.; Raval, J. V.; Ghosh, J.; Tanna, R.; Shukla, B. K.; Bhatt, S. B.

    2014-11-15

    Silicon drift detector based X-ray spectrometer diagnostic was developed to study the non-thermal electron for Aditya tokamak plasma. The diagnostic was mounted on a radial mid plane port at the Aditya. The objective of diagnostic includes the estimation of the non-thermal electron temperature for the ohmically heated plasma. Bi-Maxwellian plasma model was adopted for the temperature estimation. Along with that the study of high Z impurity line radiation from the ECR pre-ionization experiments was also aimed. The performance and first experimental results from the new X-ray spectrometer system are presented.

  10. A multiband flexible terahertz metamaterial with curvature sensing functionality

    NASA Astrophysics Data System (ADS)

    Zhao, Xiaoqing; Yang, Bin; Liu, Jingquan; Pitchappa, Prakash; Hasan, Dihan; Pei Ho, Chong; Yang, Chunsheng; Lee, Chengkuo

    2016-07-01

    In this paper, we present a multiband flexible metamaterial in which one resonance acts as a strain sensor, while the others remain unchanged with bending strain, which might occur due to wrapping around an irregular curved surface. From both experiment and simulation, four transmission dips were observed at around 0.51, 1.34, 1.72 and 1.81 THz, respectively. The results indicated that the resonance dips in the flexible metamaterial arose from the different orders of dipole resonance mode. In the experiment, the frequency shift and amplitude modulation of the transmission at the first resonance increased linearly with the increase of the relative length change Δl/L and changed as an exponential function of the applied bending strain. In addition, the first resonance frequency of the horizontal dipole blue shifted by 6.4 GHz, or about 1.29%, while the relative intensity change of 31.95% in the transmission was achieved when the strain was 2.79‰. This study promises applications in curvature sensing and other controllable metamaterial-based devices.

  11. Interleaved numerical renormalization group as an efficient multiband impurity solver

    NASA Astrophysics Data System (ADS)

    Stadler, K. M.; Mitchell, A. K.; von Delft, J.; Weichselbaum, A.

    2016-06-01

    Quantum impurity problems can be solved using the numerical renormalization group (NRG), which involves discretizing the free conduction electron system and mapping to a "Wilson chain." It was shown recently that Wilson chains for different electronic species can be interleaved by use of a modified discretization, dramatically increasing the numerical efficiency of the RG scheme [Phys. Rev. B 89, 121105(R) (2014), 10.1103/PhysRevB.89.121105]. Here we systematically examine the accuracy and efficiency of the "interleaved" NRG (iNRG) method in the context of the single impurity Anderson model, the two-channel Kondo model, and a three-channel Anderson-Hund model. The performance of iNRG is explicitly compared with "standard" NRG (sNRG): when the average number of states kept per iteration is the same in both calculations, the accuracy of iNRG is equivalent to that of sNRG but the computational costs are significantly lower in iNRG when the same symmetries are exploited. Although iNRG weakly breaks SU(N ) channel symmetry (if present), both accuracy and numerical cost are entirely competitive with sNRG exploiting full symmetries. iNRG is therefore shown to be a viable and technically simple alternative to sNRG for high-symmetry models. Moreover, iNRG can be used to solve a range of lower-symmetry multiband problems that are inaccessible to sNRG.

  12. Effects of Non-Thermal Plasma on Mammalian Cells

    PubMed Central

    Kalghatgi, Sameer; Kelly, Crystal M.; Cerchar, Ekaterina; Torabi, Behzad; Alekseev, Oleg; Fridman, Alexander; Friedman, Gary; Azizkhan-Clifford, Jane

    2011-01-01

    Thermal plasmas and lasers have been widely used in medicine to cut, ablate and cauterize tissues through heating; in contrast, non-thermal plasma produces no heat, so its effects can be selective. In order to exploit the potential for clinical applications, including wound healing, sterilization, blood coagulation, and cancer treatment, a mechanistic understanding of the interaction of non-thermal plasma with living tissues is required. Using mammalian cells in culture, it is shown here that non-thermal plasma created by dielectric barrier discharge (DBD) has dose-dependent effects that range from increasing cell proliferation to inducing apoptosis. It is also shown that these effects are primarily due to formation of intracellular reactive oxygen species (ROS). We have utilized γ-H2AX to detect DNA damage induced by non-thermal plasma and found that it is initiated by production of active neutral species that most likely induce formation of organic peroxides in cell medium. Phosphorylation of H2AX following non-thermal plasma treatment is ATR dependent and ATM independent, suggesting that plasma treatment may lead to replication arrest or formation of single-stranded DNA breaks; however, plasma does not lead to formation of bulky adducts/thymine dimers. PMID:21283714

  13. Multiband terahertz quasi-optical balanced hot-electron mixers based on dual-polarization sinuous antennas

    NASA Astrophysics Data System (ADS)

    Jiang, Zhenguo; Rahman, Syed M.; Ruggiero, Steven T.; Fay, Patrick; Liu, Lei

    2014-05-01

    Receivers based on superconducting Hot-Electron Bolometers (HEBs) are widely used for terahertz (THz) sensing owing to their advantages of high sensitivity, low noise, and low LO power requirement. Balanced HEB mixers are superior to single-element ones since the thermal noise and AM noise from the LO injection can be effectively suppressed. Although a 1.3 THz balanced waveguide HEB mixer has been reported, waveguide mixer configurations offer relatively narrow RF bandwidths. We report on the development, fabrication and characterization of a THz quasioptical balanced superconducting HEB mixer utilizing a dual-polarization sinuous antenna that can potentially achieve both multiband operation and ultra-high sensitivity. In the balanced mixer configuration, a lens-coupled four-arm sinuous antenna was designed for operation from 0.2-1.0 THz with a nearly frequency-independent embedding impedance of ~106 Ω. Two identical superconducting niobium HEB devices have been integrated at the antenna feedpoints, connecting each opposing pair of antenna arms to form a balanced mixer configuration. An air-bridge was also fabricated to separate the two mixer branches. The HEB devices were fabricated from 10 nm thick niobium film sputtered on semi-insulating silicon substrates. Each HEB device has dimensions of 80 nm × 240 nm (3 squares) for approaching a resistance of 105 Ω for impedance matching. Mixer properties including antenna radiation patterns, broadband operation and polarization isolation have been characterized. Finally, in order to achieve multiband mixer operation, electronically reconfigurable THz quasi-optical mesh filters are needed. Frequency-tunable antenna elements using Schottky varactor diodes suitable for the above applications have been designed, simulated and demonstrated at Gband (140-220 GHz) showing 50 GHz tuning range.

  14. Multiband optical variability of the blazar S5 0716+714 in outburst state during 2014-2015

    NASA Astrophysics Data System (ADS)

    Agarwal, Aditi; Gupta, Alok C.; Bachev, R.; Strigachev, A.; Semkov, E.; Wiita, Paul J.; Fan, J. H.; Pandey, U. S.; Boeva, S.; Spassov, B.

    2016-01-01

    We analysed the multiband optical behaviour of the BL Lacertae object, S5 0716+714, during its outburst state from 2014 November to 2015 March. We took data on 23 nights at three observatories, one in India and two in Bulgaria, making quasi-simultaneous observations in B, V, R, and I bands. We measured multiband optical fluxes, colour, and spectral variations for this blazar on intraday and short time-scales. The source was in a flaring state during the period analysed and displayed intense variability in all wavelengths. R-band magnitude of 11.6 was attained by the target on 2015 January 18, which is the brightest value ever recorded for S5 0716+714. The discrete correlation function method yielded good correlation between the bands with no measurable time lags, implying that radiation in these bands originate from the same region and by the same mechanism. We also used the structure function technique to look for characteristic time-scales in the light curves. During the times of rapid variability, no evidence for the source to display spectral changes with magnitude was found on either of the time-scales. The amplitude of variations tends to increase with increasing frequency with a maximum of ˜22 per cent seen during flaring states in B band. A mild trend of larger variability amplitude as the source brightens was also found. We found the duty cycle of our source during the analysed period to be ˜90 per cent. We also investigated the optical spectral energy distribution of S5 0716+714 using B, V, R, and I data points for 21 nights. We briefly discuss physical mechanisms most likely responsible for its flux and spectral variations.

  15. Multi-band Eilenberger Theory of Superconductivity: Systematic Low-Energy Projection

    NASA Astrophysics Data System (ADS)

    Nagai, Yuki; Nakamura, Hiroki

    2016-07-01

    We propose the general multi-band quasiclassical Eilenberger theory of superconductivity to describe quasiparticle excitations in inhomogeneous systems. With the use of low-energy projection matrix, the M-band quasiclassical Eilenberger equations are systematically obtained from N-band Gor'kov equations. Here M is the internal degrees of freedom in the bands crossing the Fermi energy and N is the degree of freedom in a model. Our framework naturally includes inter-band off-diagonal elements of Green's functions, which have usually been neglected in previous multi-band quasiclassical frameworks. The resultant multi-band Eilenberger and Andreev equations are similar to the single-band ones, except for multi-band effects. The multi-band effects can exhibit the non-locality and the anisotropy in the mapped systems. Our framework can be applied to an arbitrary Hamiltonian (e.g., a tight-binding Hamiltonian derived by the first-principle calculation). As examples, we use our framework in various kinds of systems, such as noncentrosymmetric superconductor CePt3Si, three-orbital model for Sr2RuO4, heavy fermion CeCoIn5/YbCoIn5 superlattice, a topological superconductor with the strong spin-orbit coupling CuxBi2Se3, and a surface system on a topological insulator.

  16. Noncommutative information is revealed from Hawking radiation as tunneling

    NASA Astrophysics Data System (ADS)

    Zhang, Baocheng; Cai, Qing-yu; Zhan, Ming-sheng; You, Li

    2011-04-01

    We revisit the tunneling process from a Schwarzschild black hole in the noncommutative spacetime and obtain the nonthermal tunneling probability. In such nonthermal spectrum, the correlations are discovered, which can carry the information about the noncommutativity. Thus this enlightens a way to find the noncommutative information in the Hawking radiation. The entropy is also shown to be conserved in the whole radiation process, which implies that the unitarity is held even for the Hawking radiation from noncommutative black holes.

  17. Synthesis of vitamin D and erythemal irradiance obtained with a multiband filter radiometer and annual variation analysis in Río Gallegos, Argentina

    NASA Astrophysics Data System (ADS)

    Orte, P. F.; Wolfram, E. A.; Salvador, J.; D'Elia, R.; Paes Leme, N.; Quel, E. J.

    2011-01-01

    In this paper we examined the annual variability of the erythemal solar radiation (a health risk) and the solar irradiance for synthesis of vitamin D (a health benefit) in Río Gallegos, Argentina. We use ultraviolet radiation measurements made by a multiband filter radiometer GUV-541 and a Brewer spectrophotometer located at CEILAP-RG Station (CITEFA-CONICET) (51° 33' S, 69° 19' W). These measurements are weighted with action spectra published by the CIE (International Commission on Illumination). An action spectrum describes the relative effectiveness of different wavelengths in the generation of a particular biological response. The analyzed data correspond to September 2008-December 2009 period. The methodology used to obtain the erythemal irradiance and synthesis of vitamin D values combines irradiance measurements of a multiband filter radiometer with modeled values (output of radiative transfer model) and measurements of a Brewer spectrophotometer. This procedure increases the instrumental capabilities of this instrument. The synthesis of vitamin D and erythema are affected by UVB solar radiation. Therefore, its effect is strongly dependent of the stratospheric ozone amount, which undergoes large variations in the Río Gallegos city due to ozone hole passage and its influence on these sub-polar latitudes. We observed that could exist cases of sunburn for reasonable exposure in abnormal situations of low total ozone column, resulting in high levels of ultraviolet radiation. Furthermore, the synthesis of vitamin D through exposure to ultraviolet radiation would be lower than the appropriate values to the majority of the year for these latitudes. Therefore it is important to evaluate the annual variation of these quantities realizing seasonal balance between this health risk and this health benefit.

  18. Non-thermal Aftertreatment of Particulates

    SciTech Connect

    Thomas, S.E.

    2000-08-20

    Modern diesel passenger vehicles employing common rail, high speed direct injection engines are capable of matching the drivability of gasoline powered vehicles with the additional benefit of providing high torque at low engine speed [1]. The diesel engine also offers considerable fuel economy and CO2 emissions advantages. However, future emissions standards [2,3] present a significant challenge for the diesel engine, as its lean exhaust precludes the use of aftertreatment strategies employing 3- way catalytic converters, which operate under stoichiometric conditions. In recent years significant developments by diesel engine manufacturers have greatly reduced emissions of both particulates (PM) and oxides of nitrogen (NOx) [4,5]. However to achieve compliance with future legislative limits it has been suggested that an integrated approach involving a combination of engine modifications and aftertreatment technology [1] will be required. A relatively new approach to exhaust aftertreatment is the application of non-thermal plasma (NTP) or plasma catalyst hybrid systems. These have the potential for treatment of both NOx and PM emissions [6- 8]. The primary focus of recent plasma aftertreatment studies [9-12] has concentrated on the removal of NOx. It has been shown that by combining plasmas with catalysts it is possible to chemically reduce NOx. The most common approach is to use a 2- stage system relying upon the plasma oxidation of hydrocarbons to promote NO to NO2 conversion as a precursor to NO2 reduction over a catalyst. However, relatively little work has yet been published on the oxidation of PM by plasma [ 8,13]. Previous investigations [8] have reported that a suitably designed NTP reactor containing a packing material designed to filter and retain PM can effect the oxidation of PM in diesel exhausts at low temperatures. It has been suggested that the retained PM competes with hydrocarbons for O, and possibly OH, radicals. This is an important consideration

  19. A model for the non-thermal emission of the very massive colliding-wind binary HD 93129A

    NASA Astrophysics Data System (ADS)

    del Palacio, Santiago; Bosch-Ramon, Valentí; Romero, Gustavo E.; Benaglia, Paula

    2016-06-01

    Context. Recently, the colliding-wind region of the binary stellar system HD 93129A was resolved for the first time using Very Large Baseline Interferometry. This system, one of the most massive known binaries in our Galaxy, presents non-thermal emission in the radio band, which can be used to infer the physical conditions in the system, and make predictions for the high-energy band. Aims: We intend to constrain some of the unknown parameters of HD 93129A through modeling the non-thermal emitter. We also aim to analyse the detectability of this source in hard X-rays and γ-rays. Finally, we want to predict how the non-thermal emission will evolve in the future, when the stars approach periastron. Methods: A broadband radiative model for the wind-collision region (WCR) has been developed taking into account the evolution of the accelerated particles streaming along the shocked region, the emission by different radiative processes, and the attenuation of the emission propagating through the local matter and radiation fields. We reproduce the available radio data, and make predictions of the emission in hard X-rays and γ-rays under different assumptions. Results: From the analysis of the radio emission, we find that the binary HD 93129A is more likely to have a low inclination and a high eccentricity, with the more massive star being currently closer to the observer. The minimum energy of the non-thermal electrons seems to be between ~20-100 MeV, depending on the intensity of the magnetic field in the WCR. The latter can be in the range ~20-1500 mG. Conclusions: Our model is able to reproduce the observed radio emission, and predicts that the non-thermal radiation from HD 93129A will increase in the near future. With instruments such as NuSTAR, Fermi, and CTA, it will be possible to constrain the relativistic particle content of the source, and other parameters such as the magnetic field strength in the WCR which, in turn, can be used to obtain upper-limits of the

  20. ON THE ROLE AND ORIGIN OF NONTHERMAL ELECTRONS IN HOT ACCRETION FLOWS

    SciTech Connect

    Niedźwiecki, Andrzej; Stȩpnik, Agnieszka

    2015-02-01

    We study the X-ray spectra of tenuous, two-temperature accretion flows using a model involving an exact, Monte Carlo computation of the global Comptonization effect as well as a general relativistic description of both the flow structure and radiative processes. In our previous work, we found that in flows surrounding supermassive black holes, thermal synchrotron radiation is not capable of providing a sufficient seed photon flux to explain the X-ray spectral indices as well as the cut-off energies measured in several best-studied active galactic nuclei (AGNs). In this work, we complete the model by including seed photons provided by nonthermal synchrotron radiation and we find that it allows us to reconcile the hot flow model with the AGN data. We take into account two possible sources of nonthermal electrons. First, we consider e {sup ±} produced by charged-pion decay, which should always be present in the innermost part of a two-temperature flow due to proton-proton interactions. We find that for a weak heating of thermal electrons (small δ) the synchrotron emission of pion-decay e {sup ±} is much stronger than the thermal synchrotron emission in the considered range of bolometric luminosities, L ∼ (10{sup –4}-10{sup –2}) L {sub Edd}. The small-δ model including hadronic effects, in general, agrees with the AGN data, except for the case of a slowly rotating black hole and a thermal distribution of protons. For large δ, the pion-decay e {sup ±} have a negligible effect and, in this model, we consider nonthermal electrons produced by direct acceleration. We find an approximate agreement with the AGN data for the fraction of the heating power of electrons, which is used for the nonthermal acceleration η ∼ 0.1. However, for constant η and δ, the model predicts a positive correlation of the X-ray spectral index with the Eddington ratio, and hence a fine tuning of η and/or δ with the accretion rate is required to explain the negative correlation

  1. On the Role and Origin of Nonthermal Electrons in Hot Accretion Flows

    NASA Astrophysics Data System (ADS)

    Niedźwiecki, Andrzej; Stȩpnik, Agnieszka; Xie, Fu-Guo

    2015-02-01

    We study the X-ray spectra of tenuous, two-temperature accretion flows using a model involving an exact, Monte Carlo computation of the global Comptonization effect as well as a general relativistic description of both the flow structure and radiative processes. In our previous work, we found that in flows surrounding supermassive black holes, thermal synchrotron radiation is not capable of providing a sufficient seed photon flux to explain the X-ray spectral indices as well as the cut-off energies measured in several best-studied active galactic nuclei (AGNs). In this work, we complete the model by including seed photons provided by nonthermal synchrotron radiation and we find that it allows us to reconcile the hot flow model with the AGN data. We take into account two possible sources of nonthermal electrons. First, we consider e ± produced by charged-pion decay, which should always be present in the innermost part of a two-temperature flow due to proton-proton interactions. We find that for a weak heating of thermal electrons (small δ) the synchrotron emission of pion-decay e ± is much stronger than the thermal synchrotron emission in the considered range of bolometric luminosities, L ~ (10-4-10-2) L Edd. The small-δ model including hadronic effects, in general, agrees with the AGN data, except for the case of a slowly rotating black hole and a thermal distribution of protons. For large δ, the pion-decay e ± have a negligible effect and, in this model, we consider nonthermal electrons produced by direct acceleration. We find an approximate agreement with the AGN data for the fraction of the heating power of electrons, which is used for the nonthermal acceleration η ~ 0.1. However, for constant η and δ, the model predicts a positive correlation of the X-ray spectral index with the Eddington ratio, and hence a fine tuning of η and/or δ with the accretion rate is required to explain the negative correlation observed at low luminosities. We note a

  2. The Hayabusa Spacecraft Asteroid Multi-band Imaging Camera (AMICA)

    NASA Astrophysics Data System (ADS)

    Ishiguro, Masateru; Nakamura, Ryosuke; Tholen, David J.; Hirata, Naru; Demura, Hirohide; Nemoto, Etsuko; Nakamura, Akiko M.; Higuchi, Yuta; Sogame, Akito; Yamamoto, Aya; Kitazato, Kohei; Yokota, Yasuhiro; Kubota, Takashi; Hashimoto, Tatsuaki; Saito, Jun

    2010-06-01

    The Hayabusa Spacecraft Asteroid Multi-band Imaging Camera (AMICA) has acquired more than 1400 multispectral and high-resolution images of its target asteroid, 25143 Itokawa, since late August 2005. In this paper, we summarize the design and performance of AMICA. In addition, we describe the calibration methods, assumptions, and models, based on measurements. Major calibration steps include corrections for linearity and modeling and subtraction of bias, dark current, read-out smear, and pixel-to-pixel responsivity variations. AMICA v-band data were calibrated to radiance using in-flight stellar observations. The other band data were calibrated to reflectance by comparing them to ground-based observations to avoid the uncertainty of the solar irradiation in those bands. We found that the AMICA signal was linear with respect to the input signal to an accuracy of ≪1% when the signal level was <3800 DN. We verified that the absolute radiance calibration of the AMICA v-band (0.55 μm) was accurate to 4% or less, the accuracy of the disk-integrated spectra with respect to the AMICA v-band was about 1%, and the pixel-to-pixel responsivity (flat-field) variation was 3% or less. The uncertainty in background zero level was 5 DN. From wide-band observations of star clusters, we found that the AMICA optics have an effective focal length of 120.80 ± 0.03 mm, yielding a field-of-view (FOV) of 5.83° × 5.69°. The resulting geometric distortion model was accurate to within a third of a pixel. We demonstrated an image-restoration technique using the point-spread functions of stars, and confirmed that the technique functions well in all loss-less images. An artifact not corrected by this calibration is scattered light associated with bright disks in the FOV.

  3. Effects of Instantaneous Multiband Dynamic Compression on Speech Intelligibility

    NASA Astrophysics Data System (ADS)

    Herzke, Tobias; Hohmann, Volker

    2005-12-01

    The recruitment phenomenon, that is, the reduced dynamic range between threshold and uncomfortable level, is attributed to the loss of instantaneous dynamic compression on the basilar membrane. Despite this, hearing aids commonly use slow-acting dynamic compression for its compensation, because this was found to be the most successful strategy in terms of speech quality and intelligibility rehabilitation. Former attempts to use fast-acting compression gave ambiguous results, raising the question as to whether auditory-based recruitment compensation by instantaneous compression is in principle applicable in hearing aids. This study thus investigates instantaneous multiband dynamic compression based on an auditory filterbank. Instantaneous envelope compression is performed in each frequency band of a gammatone filterbank, which provides a combination of time and frequency resolution comparable to the normal healthy cochlea. The gain characteristics used for dynamic compression are deduced from categorical loudness scaling. In speech intelligibility tests, the instantaneous dynamic compression scheme was compared against a linear amplification scheme, which used the same filterbank for frequency analysis, but employed constant gain factors that restored the sound level for medium perceived loudness in each frequency band. In subjective comparisons, five of nine subjects preferred the linear amplification scheme and would not accept the instantaneous dynamic compression in hearing aids. Four of nine subjects did not perceive any quality differences. A sentence intelligibility test in noise (Oldenburg sentence test) showed little to no negative effects of the instantaneous dynamic compression, compared to linear amplification. A word intelligibility test in quiet (one-syllable rhyme test) showed that the subjects benefit from the larger amplification at low levels provided by instantaneous dynamic compression. Further analysis showed that the increase in intelligibility

  4. Direct/indirect detection signatures of nonthermally produced dark matter

    SciTech Connect

    Nagai, Minoru; Nakayama, Kazunori

    2008-09-15

    We study direct and indirect detection possibilities of neutralino dark matter produced nonthermally by, e.g., the decay of long-lived particles, as is easily implemented in the case of anomaly or mirage-mediation models. In this scenario, large self-annihilation cross sections are required to account for the present dark matter abundance, and it leads to significant enhancement of the gamma-ray signature from the galactic center and the positron flux from the dark matter annihilation. It is found that GLAST and PAMELA will find the signal or give tight constraints on such nonthermal production scenarios of neutralino dark matter.

  5. Atmospheric pressure non-thermal plasma: Sources and applications

    NASA Astrophysics Data System (ADS)

    Napartovich, A. P.

    2008-07-01

    Non-thermal plasma at atmospheric pressure is an inherently unstable object. Nature of discharge plasma instabilities and conditions for observation of uniform non-thermal plasma at atmospheric pressure in different environments will be discussed. Various discharge techniques have been developed, which could support uniform non-thermal plasma with parameters varied in a wide range. Time limitation by plasma instabilities can be overcome by shortening pulse length or by restriction of plasma plug residence time with a fast gas flow. Discharge instabilities leading to formation of filaments or sparks are provoked by a positive feedback between the electric field and plasma density, while the counteracting process is plasma and thermal diffusion. With gas pressure growth the size of plasma fluctuation, which could be stabilized by diffusion, diminishes. As a result, to have long lived uniform plasma one should miniaturize discharge. There exist a number of active methods to organize negative feedback between the electric field and plasma density in order to suppress or, at least, delay the instability. Among them are ballast resistors in combination with electrode sectioning, reactive ballast, electronic feedback, and dielectric barrier across the electric current. The last methods are relevant for ac discharges. In the lecture an overview will be given of different discharge techniques scalable in pressure up to one atmosphere. The interest in this topic is dictated by a potential economic benefit from numerous non-thermal plasma technologies. The spectrum of non-thermal plasma applications is continuously broadening. An incomplete list of known applications includes: plasma-assisted chemical vapor deposition, etching, polymerization, gas-phase synthesis, protective coating deposition, toxic and harmful gas decomposition, destruction of warfare agents, electromagnetic wave shielding, polymer surface modifications, gas laser excitation, odor control, plasma assisted

  6. RXTE Observations of M87: Investigating the Nonthermal Continuum

    NASA Technical Reports Server (NTRS)

    Reynolds, Christopher S.

    2001-01-01

    This is the final report for NASA grant, awarded for the RXTE Cycle 3 Guest Observer Program, "Investigating the nonthermal continuum".It supported analysis of RXTE observations of the nearby giant elliptical galaxy M87 with the RXTE satellite. The main aim of these observations was to search for non-thermal emission from the core of M87 and the famous jet. This grant also partially funded supporting theoretical work. The observational campaign was performed in December 1997 and January 1998. The results of our detailed analysis were submitted to the Astrophysical Journal in November 1998, and accepted for publication in March 1999. The paper was published in August 1999.

  7. Triangle orientation discrimination performance model for a multiband IR imaging system with human vision

    NASA Astrophysics Data System (ADS)

    Liu, Xin; Wang, Xiaorui; Zhang, Jianqi; Bai, Honggang

    2011-08-01

    In support of multiband imaging system performance forecasting, an equation-based triangle orientation discrimination (TOD) model is developed. Specifically, with the characteristic of the test pattern related to spectrum, the mathematical equations for predicting the TOD threshold of the system with distributed fusion architecture in the IR spectrum band are derived based on human vision with the ``k/N'' fusion rule, with emphasis on the impacts of fusion on the threshold. Furthermore, a figure of merit Q related to the TOD calculation results is introduced to analyze the relation of the discrimination performance of multiband imaging system to the size and the spectral difference of test pattern. The preliminary validation with the experiment results suggests that our proposed model can provide a reasonable prediction of the performance for a multiband imaging system.

  8. Multiband array detection and location of seismic sources recorded by dense seismic networks

    NASA Astrophysics Data System (ADS)

    Poiata, Natalia; Satriano, Claudio; Vilotte, Jean-Pierre; Bernard, Pascal; Obara, Kazushige

    2016-06-01

    We present a new methodology for detection and space-time location of seismic sources based on multiscale, frequency-selective coherence of the wave field recorded by dense large-scale seismic networks and local antennas. The method is designed to enhance coherence of the signal statistical features across the array of sensors and consists of three steps: signal processing, space-time imaging, and detection and location. The first step provides, for each station, a simplified representation of seismic signal by extracting multiscale non-stationary statistical characteristics, through multiband higher-order statistics or envelopes. This signal processing scheme is designed to account for a priori unknown transients, potentially associated with a variety of sources (e.g. earthquakes, tremors), and to prepare data for a better performance in posterior steps. Following space-time imaging is carried through 3-D spatial mapping and summation of station-pair time-delay estimate functions. This step produces time-series of 3-D spatial images representing the likelihood that each pixel makes part of a source. Detection and location is performed in the final step by extracting the local maxima from the 3-D spatial images. We demonstrate the efficiency of the method in detecting and locating seismic sources associated with low signal-to-noise ratio on an example of the aftershock earthquake records from local stations of International Maule Aftershock Deployment in Central Chile. The performance and potential of the method to detect, locate and characterize the energy release associated with possibly mixed seismic radiation from earthquakes and low-frequency tectonic tremors is further tested on continuous data from southwestern Japan.

  9. Multi-band array detection and location of seismic sources recorded by dense seismic networks

    NASA Astrophysics Data System (ADS)

    Poiata, Natalia; Satriano, Claudio; Vilotte, Jean-Pierre; Bernard, Pascal; Obara, Kazushige

    2016-02-01

    We present a new methodology for detection and space-time location of seismic sources based on multi-scale, frequency-selective coherence of the wave field recorded by dense large-scale seismic networks and local antennas. The method is designed to enhance coherence of the signal statistical features across the array of sensors and consists of three steps: signal processing, space-time imaging, and detection and location. The first step provides, for each station, a simplified representation of seismic signal by extracting multi-scale non-stationary statistical characteristics, through multi-band higher-order statistics or envelopes. This signal processing scheme is designed to account for a priori unknown transients, potentially associated with a variety of sources (e.g., earthquakes, tremors), and to prepare data for a better performance in posterior steps. Following space-time imaging is carried through 3D spatial mapping and summation of station-pair time-delay estimate functions. This step produces time series of 3D spatial images representing the likelihood that each pixel makes part of a source. Detection and location is performed in the final step by extracting the local maxima from the 3D spatial images. We demonstrate the efficiency of the method in detecting and locating seismic sources associated with low signal-to-noise ratio on an example of the aftershock earthquake records from local stations of International Maule Aftershock Deployment in Central Chile. The performance and potential of the method to detect, locate and characterize the energy release associated with possibly mixed seismic radiation from earthquakes and low-frequency tectonic tremors is further tested on continuous data from southwestern Japan.

  10. Origin of multi-band emission from the microquasar Cygnus X-1

    SciTech Connect

    Zhang, Jianfu; Lu, Jufu; Xu, Bing

    2014-06-20

    We study the origin of non-thermal emissions from the Galactic black hole X-ray binary Cygnus X-1, which is a confirmed high-mass microquasar. By analogy with the methods used in studies of active galactic nuclei, we propose a two-dimensional, time-dependent radiation model from the microquasar Cygnus X-1. In this model, the evolution equation for relativistic electrons in a conical jet are numerically solved by including escape, adiabatic, and various radiative losses. The radiative processes involved are synchrotron emission, its self-Compton scattering, and inverse Compton scatterings of an accretion disk and its surrounding stellar companion. This model also includes an electromagnetic cascade process of an anisotropic γ-γ interaction. We study the spectral properties of electron evolution and its emission spectral characteristic at different heights of the emission region located in the jet. We find that radio data from Cygnus X-1 are reproduced by the synchrotron emission, the Fermi Large Area Telescope measurements by the synchrotron emission and Comptonization of photons of the stellar companion, and the TeV band emission fluxes by the Comptonization of the stellar photons. Our results show the following. (1) The radio emission region extends from the binary system scales to the termination of the jet. (2) The GeV band emissions should originate from the distance close to the binary system scales. (3) The TeV band emissions could be inside the binary system, and these emissions could be probed by the upcoming Cherenkov Telescope Array. (4) The MeV tail emissions, which produce a strongly linearly polarized signal, are emitted inside the binary system. The location of the emissions is very close to the inner region of the jet.

  11. Magnetic behavior of dirty multiband superconductors near the upper critical field

    NASA Astrophysics Data System (ADS)

    Silaev, Mikhail

    2016-06-01

    Magnetic properties of dirty multiband superconductors near the upper critical field are studied. The parameter κ2 characterizing magnetization slope is shown to have a significant temperature variation which is quite sensitive to the pairing interactions and relative strengths of intraband impurity scattering. In contrast to single-band superconductors the increase of κ2 at low temperatures can be arbitrarily large determined by the ratio of maximal and minimal diffusion coefficients in different bands. Temperature dependencies of κ2(T ) in two-band MgB2 and iron-based superconductors are shown to be much more sensitive to the multiband effects than the upper critical field Hc 2(T ) .

  12. Investigation of nonthermal particle effects on ionization dynamics in high current density ion beam transport experiments

    NASA Astrophysics Data System (ADS)

    Chung, H. K.; MacFarlane, J. J.; Wang, P.; Moses, G. A.; Bailey, J. E.; Olson, C. L.; Welch, D. R.

    1997-01-01

    Light ion inertial fusion experiments require the presence of a moderate density background gas in the transport region to provide charge and current neutralization for a high current density ion beam. In this article, we investigate the effects of nonthermal particles such as beam ions or non-Maxwellian electron distributions on the ionization dynamics of the background gas. In particular, we focus on the case of Li beams being transported in an argon gas. Nonthermal particles as well as thermal electrons are included in time-dependent collisional-radiative calculations to determine time-dependent atomic level populations and charge state distributions in a beam-produced plasma. We also briefly discuss the effects of beam ions and energetic electrons on the visible and vacuum ultraviolet (VUV) spectral regions. It is found that the mean charge state of the gas, and hence the electron density, is significantly increased by collisions with energetic particles. This higher ionization significantly impacts the VUV spectral region, where numerous resonance lines occur. On the other hand, the visible spectrum tends to be less affected because the closely spaced excited states are populated by lower energy thermal electrons.

  13. Evaluation of thermal and non-thermal effects of UHF RFID exposure on biological drugs.

    PubMed

    Calcagnini, Giovanni; Censi, Federica; Maffia, Michele; Mainetti, Luca; Mattei, Eugenio; Patrono, Luigi; Urso, Emanuela

    2012-11-01

    The Radio Frequency Identification (RFID) technology promises to improve several processes in the healthcare scenario, especially those related to traceability of people and things. Unfortunately, there are still some barriers limiting the large-scale deployment of these innovative technologies in the healthcare field. Among these, the evaluation of potential thermal and non-thermal effects due to the exposure of biopharmaceutical products to electromagnetic fields is very challenging, but still slightly investigated. This paper aims to setup a controlled RF exposure environment, in order to reproduce a worst-case exposure of pharmaceutical products to the electromagnetic fields generated by the UHF RFID devices placed along the supply chain. Radiated powers several times higher than recommended by current normative limits were applied (10 W and 20 W). The electric field strength at the exposed sample location, used in tests, was as high as 100 V/m. Non-thermal effects were evaluated by chromatography techniques and in vitro assays. The results obtained for a particular case study, the ActrapidTM human insulin preparation, showed temperature increases lower than 0.5 °C and no significant changes in the structure and performance of the considered drug. PMID:22717524

  14. Constraints on the non-thermal emission from η Carinae's blast wave of 1843

    NASA Astrophysics Data System (ADS)

    Skilton, J. L.; Domainko, W.; Hinton, J. A.; Jones, D. I.; Ohm, S.; Urquhart, J. S.

    2012-03-01

    Non-thermal hard X-ray and high-energy (HE; 1 MeV < E < 100 GeV) γ-ray emission in the direction of η Carinae has been recently detected using the INTEGRAL, AGILE and Fermi satellites. This emission has been interpreted either in the framework of particle acceleration in the colliding wind region between the two massive stars or in the very fast moving blast wave which originates in the historical 1843 "great eruption". Archival Chandra data has been reanalysed to search for signatures of particle acceleration in η Carinae's blast wave. No shell-like structure could be detected in hard X-rays and a limit has been placed on the non-thermal X-ray emission from the shell. The time dependence of the target radiation field of the Homunculus is used to develop a single zone model for the blast wave. Attempting to reconcile the X-ray limit with the HE γ-ray emission using this model leads to a very hard electron injection spectrum dN/dE ∝ E - Γ with Γ < 1.8, harder than the canonical value expected from diffusive shock acceleration.

  15. Nonthermal processing technologies as food safety intervention processes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Foods should provide sensorial satisfaction and nutrition to people. Yet, foodborne pathogens cause significant illness and lose of life to human kind every year. A processing intervention step may be necessary prior to the consumption to ensure the safety of foods. Nonthermal processing technologi...

  16. FEASIBILITY ANALYSIS REPORT FOR HYBRID NON-THERMAL PLASMA REACTORS

    EPA Science Inventory

    The purpose of SERDP project CP-1038 is to evaluate and develop non-thermal plasma (NTP) reactor technology for DoD air emissions control applications. The primary focus is on oxides of nitrogen (NOx) and a secondary focus on hazardous air pollutants (HAPs), especially volatile o...

  17. Effect of Non-Thermal Processing on Peanut Allergens.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Peanut allergy is on the rise, and the reason is still unclear. Previously, roasting by thermal method has been shown to increase the allergenic potency of peanuts. In this study, we determined if non-thermal methods, such as, pulsed electric fields (PEF) and pulsed UV lights (PUV) affect peanut all...

  18. NONTHERMAL PLASMA (NTP) AS A NOVEL FOOD PROCESSING TECHNOLOGY

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Modern food processing requires tools to ensure the safety of foods by effectively sanitizing without compromising food quality. This has led to an increased interest in nonthermal processing for meat, poultry and dairy products, produce and beverages. Plasma (an energetic ionized gas) is widely use...

  19. Are the nonthermal technologies cost effective and environmentally friendly

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The main goal of the application of nonthermal technologies such as pulsed electric fields (PEF) and high pressure processing (HPP) is to produce safe, fresher and more nutritious food. However, despite extensive microbiological data available, cost analysis and environmental impact studies of these...

  20. Cold Plasma as a nonthermal food processing technology

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Contamination of fresh and fresh-cut fruits and vegetables by foodborne pathogens has prompted research into novel interventions. Cold plasma is a nonthermal food processing technology which uses energetic, reactive gases to inactivate contaminating microbes. This flexible sanitizing method uses ele...

  1. Application of a non-thermal plasma to combustion enhancement.

    SciTech Connect

    Rosocha, L. A.; Kim, Y.; Stange, Sabine

    2004-01-01

    As a primary objective, researchers in Los Alamos National Laboratory's P-24 Plasma Physics group are aiming to minimize U.S. energy dependency on foreign resources through experiments incorporating a plasma assisted combustion unit. Under this broad category, researchers seek to increase efficiency and reduce NO{sub x}/SO{sub x} and unburned hydrocarbon emissions in IC-engines, gas-turbine engines, and burner units. To date, the existing lean burn operations, consisting of higher air to fuel ratio, have successfully operated in a regime where reduced NO{sub x}/SO{sub x} emissions are expected and have also shown increased combustion efficiency (less unburned hydrocarbon) for propane. By incorporating a lean burn operation assisted by a non-thermal plasma (NTP) reactor, the fracturing of hydrocarbons can occur with increased power (combustion, efficiency, and stability). Non-thermal plasma units produce energetic electrons, but avoid the high gas and ion temperatures involved in thermal plasmas. One non-thermal plasma method, known as silent discharge, allows free radicals to act in propagating combustion reactions, as well as intermediaries in hydrocarbon fracturing. Using non-thermal plasma units, researchers have developed a fuel activation/conversion system capable of decreasing pollutants while increasing fuel efficiency, providing a path toward future U.S. energy independence.

  2. Combined effects of laser and non-thermal electron beams on hydrodynamics and shock formation in the Shock Ignition scheme

    NASA Astrophysics Data System (ADS)

    Nicolai, Ph.; Feugeas, J. L.; Touati, M.; Breil, J.; Dubroca, B.; Nguyen-Buy, T.; Ribeyre, X.; Tikhonchuk, V.; Gus'kov, S.

    2014-10-01

    An issue to be addressed in Inertial Confinement Fusion (ICF) is the detailed description of the kinetic transport of relativistic or non-thermal electrons generated by laser within the time and space scales of the imploded target hydrodynamics. We have developed at CELIA the model M1, a fast and reduced kinetic model for relativistic electron transport. The latter has been implemented into the 2D radiation hydrodynamic code CHIC. In the framework of the Shock Ignition (SI) scheme, it has been shown in simplified conditions that the energy transferred by the non-thermal electrons from the corona to the compressed shell of an ICF target could be an important mechanism for the creation of ablation pressure. Nevertheless, in realistic configurations, taking the density profile and the electron energy spectrum into account, the target has to be carefully designed to avoid deleterious effects on compression efficiency. In addition, the electron energy deposition may modify the laser-driven shock formation and its propagation through the target. The non-thermal electron effects on the shock propagation will be analyzed in a realistic configuration.

  3. Ultrahigh Efficiency Multiband Solar Cells Final Report forDirector's Innovation Initiative Project DII-2005-1221

    SciTech Connect

    Ager III, Joel W.; Walukiewicz, W.; Yu, Kin Man

    2006-03-29

    The unique properties of the semiconductor ZnTeO were explored and developed to make multiband solar cells. Like a multijunction cell, multiband solar cells use different energy gaps to convert the majority of the solar spectrum to electrical current while minimizing losses due to heating. Unlike a multijunction cell, this is accomplished within a single material in a multiband cell. ZnTe{sub 1-x}O{sub x} films with x up to 2% were synthesized and shown to have the requisite unique band structure (2 conduction bands) for multiband function. Prototype solar cells based on an n-type ZnTe{sub 1-x}O{sub x} multiband top layer and a p-type ZnTe substrate were fabricated. Contacts to the cell and the series resistance of the substrate were identified as challenges for good electrical performance. Both photovoltage and small photocurrents were demonstrated under AMO illumination. A second semiconductor system, GaN{sub x}As{sub 1-y-x}P{sub y}, was shown to have multiband function. This alloy system may have the greatest potential to realize the promise of high efficiency multiband solar cells because of the relatively advanced technology base that exists for the manufacturing of III-V-alloy-based IC and opto-electronic devices (including multijunction solar cells).

  4. Cataracts and avionic radiations.

    PubMed Central

    Zaret, M M; Snyder, W Z

    1977-01-01

    Nine cases of hertzian radiation cataracts are reported among personnel working in operational aviation environments, where they were irradiated repeatedly at subliminal non-thermal field intensities. The resultant ocular pathology evolved insidiously and slowly over a period of years in a similar way to other forms of radiational injury. By the time of consultation examination, all had progressed to a relatively late state, exhibiting not only capsular cataract but also vesiculation and opacification of the proximal subcapsular lens substance. In addition to the ocular dangers of chronic exposure to nonionising radiation reference is made to the nonthermal effect or the radiation effect per se, as this could relate to general health--for example, as a possible previously unsuspected aetiological or contributory factor in many other disease processes. Images PMID:871464

  5. Test-retest reliability of white matter structural brain networks: a multiband diffusion MRI study

    PubMed Central

    Zhao, Tengda; Duan, Fei; Liao, Xuhong; Dai, Zhengjia; Cao, Miao; He, Yong; Shu, Ni

    2015-01-01

    The multiband EPI sequence has been developed for the human connectome project to accelerate MRI data acquisition. However, no study has yet investigated the test-retest (TRT) reliability of the graph metrics of white matter (WM) structural brain networks constructed from this new sequence. Here, we employed a multiband diffusion MRI (dMRI) dataset with repeated scanning sessions and constructed both low- and high-resolution WM networks by volume- and surface-based parcellation methods. The reproducibility of network metrics and its dependence on type of construction procedures was assessed by the intra-class correlation coefficient (ICC). We observed conserved topological architecture of WM structural networks constructed from the multiband dMRI data as previous findings from conventional dMRI. For the global network properties, the first order metrics were more reliable than second order metrics. Between two parcellation methods, networks with volume-based parcellation showed better reliability than surface-based parcellation, especially for the global metrics. Between different resolutions, the high-resolution network exhibited higher TRT performance than the low-resolution in terms of the global metrics with a large effect size, whereas the low-resolution performs better in terms of local (region and connection) properties with a relatively low effect size. Moreover, we identified that the association and primary cortices showed higher reproducibility than the paralimbic/limbic regions. The important hub regions and rich-club connections are more reliable than the non-hub regions and connections. Finally, we found WM networks from the multiband dMRI showed higher reproducibility compared with those from the conventional dMRI. Together, our results demonstrated the fair to good reliability of the WM structural brain networks from the multiband EPI sequence, suggesting its potential utility for exploring individual differences and for clinical applications. PMID

  6. Relativistic magnetosonic shock waves in synchrotron sources - Shock structure and nonthermal acceleration of positrons

    NASA Technical Reports Server (NTRS)

    Hoshino, Masahiro; Arons, Jonathan; Gallant, Yves A.; Langdon, A. B.

    1992-01-01

    The theoretical properties of relativistic, transverse, magnetosonic collisionless shock waves in electron-positron-heavy ion plasmas of relevance to astrophysical sources of synchrotron radiation are investigated. Both 1D electromagnetic particle-in-cell simulations and quasi-linear theory are used to examine the spatial and kinetic structure of these nonlinear flows. A new process of shock acceleration of nonthermal positrons, in which the gyrating reflected heavy ions dissipate their energy in the form of collectively emitted, left-handed magnetosonic waves which are resonantly absorbed by the positrons immediately behind the ion reflection region, is described. Applications of the results to the termination shocks of pulsar winds and to the termination shocks of jets emanating from the AGN are outlined.

  7. Characterizing canopy nonrandomness with a multiband vegetation imager (MVI)

    NASA Astrophysics Data System (ADS)

    Kucharik, C. J.; Norman, J. M.; Murdock, L. M.; Gower, S. T.

    1997-12-01

    A new method for measuring plant canopy nonrandomness and other architectural components has been developed using a 16 bit (65535 gray scale levels) charged-coupled device (CCD) camera that captures images of plant canopies in two wavelength bands. This complete system is referred to as a multiband vegetation imager (MVI). The use of two wavelength bands (visible (VIS) 400-620 nm and near infrared (NIR) 720-950 nm) permits identification of sunlit and shaded foliage, sunlit and shaded branch area, clouds, and blue sky based on the camera's resolution, and the varying spectral properties that scene components have in the two wavelength bands. This approach is different from other canopy imaging methods (such as fish-eye photography) because it emphasizes measuring the fraction of an image occupied by various scene components (branches, shaded leaves, sunlit leaves) under different sky conditions rather than simply the canopy gap fraction under uniform sky conditions. The MVI has been used during the Boreal Ecosystem-Atmosphere Study (BOREAS) in aspen (Populus tremuloides) and balsam poplar (Populus balsamifera) to estimate architectural characteristics of each canopy. The leaf area index (LAI), sunlit LAI, and degree of nonrandomness within a canopy are architectural properties that have been measured with the MVI. Using a crown-based Monte Carlo model for nonrandom canopies, nonrandomness factors are calculated from MVI data using two approaches (gap fraction and gap-size distribution theories) to correct total and sunlit LAI estimates from indirect methods that assume random foliage distributions. Canopy nonrandomness factors obtained from analyzing the gap-size distribution in a Monte Carlo model are shown to be a function of path length (angle) through the canopy (Ωe(θ)); thus we suggest that LAI-2000 indirect measurements of LAI be adjusted with the value of Ωe(θ) at θ=35° because this is the mean angle at which the canopy gap fraction is measured by the

  8. A fluid-particle hybrid framework for the PLUTO code: applications to non-thermal emission in jets.

    NASA Astrophysics Data System (ADS)

    Vaidya, B.; Mignone, A.; Bodo, G.; Massaglia, S.

    2016-05-01

    We present an implementation of a fully parallel hybrid framework for the evolution of Lagrangian particles coupled to a MHD fluid for the PLUTO code. For the applications of interest, particles represent ensembles of electrons whose spectral energy distribution is governed by a kinetic transport equation that takes into account different physical processes such as diffusive shock acceleration, synchrotron emission and adiabatic expansion. An application to model non-thermal emission from extragalactic jets shows the effectiveness and strength of the approach in describing not only the dynamics but also the radiation properties of jets and, in general, of high-energy astrophysical plasma environments.

  9. Non-thermal irreversible electroporation for deep intracranial disorders.

    PubMed

    Garcia, Paulo A; Neal, Robert E; Rossmeisl, John H; Davalos, Rafael V

    2010-01-01

    Non-thermal irreversible electroporation (N-TIRE) is a new minimally invasive technique to kill undesirable tissue. We build on our previous intracranial studies in order to evaluate the possibility of using N-TIRE for deep intracranial disorders. In this manuscript we describe a minimally invasive computed tomography (CT) guided N-TIRE procedure in white matter. In addition, we report the electric field threshold needed for white matter ablation (630 - 875 V/cm) using four sets of twenty 50 µs pulses at a voltage-to-distance ratio of 1000 V/cm. We also confirm the non-thermal aspect of the technique with real time temperature data measured at the electrode-tissue interface. PMID:21095962

  10. CO2 reduction using adsorption followed by nonthermal plasma treatment

    NASA Astrophysics Data System (ADS)

    Nakajima, Kenji; Takahashi, Kazuya; Tanaka, Masanari; Kuroki, Tomoyuki; Okubo, Masaaki

    2015-10-01

    Carbon dioxide (CO2) is one of the main substances linked to global warming, and its emission should be reduced. In this study, a CO2 reduction treatment using an adsorbent and a nonthermal plasma flow is investigated. This treatment comprises a physical adsorption process and nitrogen (N2) plasma reduction process. In the physical adsorption process, CO2 is adsorbed by the adsorbent. In the N2 plasma reduction process, the adsorbed CO2 is reduced to CO by a nonthermal plasma flow that is generated by a plasma reactor with a circulating N2 plasma flow. The generated CO can be reused as a fuel. We estimate this experimental results by calculating conversion efficiency of CO2 to CO. In the N2 plasma reduction process, the CO concentration reaches approximately 1%, regardless of the number of experiments, and conversion efficiency reaches at most 5.3%.

  11. Process modeling for the Integrated Nonthermal Treatment System (INTS) study

    SciTech Connect

    Brown, B.W.

    1997-04-01

    This report describes the process modeling done in support of the Integrated Nonthermal Treatment System (INTS) study. This study was performed to supplement the Integrated Thermal Treatment System (ITTS) study and comprises five conceptual treatment systems that treat DOE contract-handled mixed low-level wastes (MLLW) at temperatures of less than 350{degrees}F. ASPEN PLUS, a chemical process simulator, was used to model the systems. Nonthermal treatment systems were developed as part of the INTS study and include sufficient processing steps to treat the entire inventory of MLLW. The final result of the modeling is a process flowsheet with a detailed mass and energy balance. In contrast to the ITTS study, which modeled only the main treatment system, the INTS study modeled each of the various processing steps with ASPEN PLUS, release 9.1-1. Trace constituents, such as radionuclides and minor pollutant species, were not included in the calculations.

  12. Nonthermal and suprathermal distributions as a consequence of superstatistics

    NASA Astrophysics Data System (ADS)

    Ourabah, Kamel; Ait Gougam, Leila; Tribeche, Mouloud

    2015-01-01

    We propose to put the well-known nonthermal and suprathermal empirical distributions, used in plasma physics, onto a more rigorous foundation. Their use is frequently criticized because of a lack of formal derivation and physical explanation. A connection between these non-Maxwellian distributions and the Beck-Cohen superstatistics is suggested. They are perceived as a consequence of typical temperature fluctuations. We show that the suprathermal distribution is generated by the Γ distribution of the inverse temperature, in the same way as the Tsallis q statistics. The nonthermal distribution also follows from the χ2 distribution, with a small variance. Our contribution provides a possible physical meaning for these ad hoc distributions.

  13. On nonthermal processes in the core of the Sun

    SciTech Connect

    Voronchev, V. T.

    2015-06-15

    Nonthermal nuclear processes in the core of the Sun that are induced by fast particles appearing as nonthermalized products of exothermic reactions are discussed. Among other things, properties of 8.7-MeV alpha particles originating from the reaction p + {sup 7}Li → 2α are studied, and their effect on the balance of the processes p + {sup 17}O ai α + {sup 14}N, which close the CNO-II cycle, is determined. It is shown that the effective temperature of fast alpha particles is approximately 1000 times as high as the temperature of the plasma in the Sun’s core and that, under some specific conditions, the rate of the reverse reaction α + {sup 14}N → p + {sup 17}O may be one to two orders of magnitude higher than the rate of the forward reaction p + {sup 17}O → α + {sup 14}N.

  14. Auroral electrostatic solitons and supersolitons in a magnetized nonthermal plasma

    SciTech Connect

    Rufai, O. R.

    2015-05-15

    Exploiting the spacecraft measurements in the auroral region, finite amplitude nonlinear low frequency electrostatic solitons and supersolitons in a magnetized plasma consisting of cold ions fluid, Boltzmann protons, and nonthermal hot electrons are studied by applying a pseudo-potential technique. The localized solution of the nonlinear structures is obtained through the charge neutrality condition. Further numerical investigation shows the existence of supersoliton solutions at supersonic Mach numbers regime. The amplitude of ion-acoustic structures decreased with an increase in nonthermal electrons and ion density ratio. For the plasma parameters relevant to the auroral zone of the Earth's magnetosphere, the electric field amplitude of supersolitons is found to be about 9 mV/m, which is in agreement with satellite observations.

  15. Modeling the interaction between convection and nonthermal ion outflows

    NASA Astrophysics Data System (ADS)

    Varney, R. H.; Wiltberger, M.; Lotko, W.

    2015-03-01

    Initial demonstrations of an ionosphere/polar wind model including a phenomenological treatment of transverse heating by wave particle interactions (WPIs) are presented. Tests with fixed WPI parameters in a designated heating region on the dayside with time-varying convection show that the parameters of the resulting nonthermal ion outflow are strongly coupled to the convection. The hemispheric outflow rate is positively correlated with the convection speed with a time delay related to the travel time to the upper boundary. Increases in convection increase the thermal plasma access to the heating region, both by increasing the upflow associated with frictional heating and by increasing the horizontal transport. The average parallel velocities and energies of the escaping nonthermal ions are anticorrelated with the convection speed due to the finite dwell time in the heating region. The computationally efficient model can be readily coupled into global geospace modeling frameworks in the future.

  16. Review of the integrated thermal and nonthermal treatment system studies

    SciTech Connect

    1996-10-01

    This report contains a review and evaluation of three systems analysis studies performed by LITCO on integrated thermal treatment systems and integrated nonthermal treatment systems for the remediation of mixed low-level waste stored throughout the US Department of Energy weapons complex. The review was performed by an independent team of nine researchers from the Energy and Environmental Research Center, Science Applications International Corporation, the Waste Policy Institute, and Virginia Tech. The purpose of this review was to (1) determine whether the assumptions of the studies were adequate to produce an unbiased review of both thermal and nonthermal systems, (2) to identify the critical areas of the studies that would benefit from further investigation, and (3) to develop a standard template that could be used in future studies to assure a sound application of systems engineering.

  17. Non-thermal plasma for exhaust gases treatment

    NASA Astrophysics Data System (ADS)

    Alva R., Elvia; Pacheco P., Marquidia; Gómez B., Fernando; Pacheco P., Joel; Colín C., Arturo; Sánchez-Mendieta, Víctor; Valdivia B., Ricardo; Santana D., Alfredo; Huertas C., José; Frías P., Hilda

    2015-09-01

    This article describes a study on a non-thermal plasma device to treat exhaust gases in an internal combustion engine. Several tests using a plasma device to treat exhaust gases are conducted on a Honda GX200-196 cm3 engine at different rotational speeds. A plasma reactor could be efficient in degrading nitrogen oxides and particulate matter. Monoxide and carbon dioxide treatment is minimal. However, achieving 1%-3% degradation may be interesting to reduce the emission of greenhouse gases.

  18. Non-thermal emission in astrophysical environments: From pulsars to supernova remnants

    NASA Astrophysics Data System (ADS)

    Lomiashvili, David

    The study of electromagnetic radiation from distant astrophysical objects provides essential data in understanding physics of these sources. In particular, non-thermal radiation provides great insight into the properties of local environments, particle populations, and emission mechanisms, knowledge which otherwise would remain untapped. Throughout the projects conducted for this dissertation, we modeled certain aspects of observed non-thermal emission from three classes of sources: radio pulsars, pulsar wind nebulae, and supernova remnants. Orbital variation in the double pulsar system PSR J0737-3039A/B can be used to probe the details of the magnetospheric structure of pulsar B. Strongly magnetized wind from pulsar A distorts the magnetosphere of pulsar B in a way similar to the solar wind's distortion of the Earth's magnetosphere. Using the two complimentary models of pulsar B's magnetosphere, adapted from the Earth's magnetosphere models by Dungey and Tsyganenko, we determine the precise location of the coherent radio emission generation region in pulsar B's magnetosphere. This analysis is complemented by modeling the observed evolution of the pulse profiles of B due to geodetic precession. The emission region is located at about 3750 stellar radii and has a horseshoe-like shape centered on the polar magnetic field lines. The best fit angular parameters of the emission region indicate that radio emission is generated on the field lines which, according to the theoretical models, originate close to the poles and carry the maximum current. When considered together, not only do the results of the two models converge, they can explain why the modulation of B's radio emission at A's period is observed only within a certain orbital phase region. We discuss the implications of these results for pulsar magnetospheric models and mechanisms of coherent radio emission generation. We also developed a spatially-resolved, analytic model for the high-energy non-thermal

  19. Non-thermal plasma mills bacteria: Scanning electron microscopy observations

    NASA Astrophysics Data System (ADS)

    Lunov, O.; Churpita, O.; Zablotskii, V.; Deyneka, I. G.; Meshkovskii, I. K.; Jäger, A.; Syková, E.; Kubinová, Š.; Dejneka, A.

    2015-02-01

    Non-thermal plasmas hold great promise for a variety of biomedical applications. To ensure safe clinical application of plasma, a rigorous analysis of plasma-induced effects on cell functions is required. Yet mechanisms of bacteria deactivation by non-thermal plasma remain largely unknown. We therefore analyzed the influence of low-temperature atmospheric plasma on Gram-positive and Gram-negative bacteria. Using scanning electron microscopy, we demonstrate that both Gram-positive and Gram-negative bacteria strains in a minute were completely destroyed by helium plasma. In contrast, mesenchymal stem cells (MSCs) were not affected by the same treatment. Furthermore, histopathological analysis of hematoxylin and eosin-stained rat skin sections from plasma-treated animals did not reveal any abnormalities in comparison to control ones. We discuss possible physical mechanisms leading to the shred of bacteria under non-thermal plasma irradiation. Our findings disclose how helium plasma destroys bacteria and demonstrates the safe use of plasma treatment for MSCs and skin cells, highlighting the favorability of plasma applications for chronic wound therapy.

  20. Toward a Philosophy and Theory of Volumetric Nonthermal Processing.

    PubMed

    Sastry, Sudhir K

    2016-06-01

    Nonthermal processes for food preservation have been under intensive investigation for about the past quarter century, with varying degrees of success. We focus this discussion on two volumetrically acting nonthermal processes, high pressure processing (HPP) and pulsed electric fields (PEF), with emphasis on scientific understanding of each, and the research questions that need to be addressed for each to be more successful in the future. We discuss the character or "philosophy" of food preservation, with a question about the nature of the kill step(s), and the sensing challenges that need to be addressed. For HPP, key questions and needs center around whether its nonthermal effectiveness can be increased by increased pressures or pulsing, the theoretical treatment of rates of reaction as influenced by pressure, the assumption of uniform pressure distribution, and the need for (and difficulties involved in) in-situ measurement. For PEF, the questions include the rationale for pulsing, difficulties involved in continuous flow treatment chambers, the difference between electroporation theory and experimental observations, and the difficulties involved in in-situ measurement and monitoring of electric field distribution. PMID:27149642

  1. A nonthermal superbubble in the irregular galaxy IC 10

    NASA Technical Reports Server (NTRS)

    Yang, Hui; Skillman, Evan D.

    1993-01-01

    We present synthesis radio continuum observations of the nearby irregular galaxy IC 10. These observations, at 6, 20, and 49 cm, allow us to measure the flux and spectral index of a number of resolved sources in IC 10. While most of these are easily identified as thermal emission from H II regions and a few are nonthermal background sources, one extended, nonthermal source appears to be a superbubble in IC 10. Its large size (about 250 pc) implies that it is most likely the product of several supernovae. Comparisons of these radio observations with Halpha, H I, and optical imaging observations reveal that the large nonthermal superbubble is associated with a region of star formation containing two of the most luminous H II regions and the most massive H I cloud in IC 10. We tentatively identify a stellar cluster with two Wolf-Rayet stars in the center of the superbubble. We propose that this superbubble in IC 10 represents a bridge between the giant H II regions and the H I shells and supershells observed in our Galaxy and external galaxies.

  2. Non-thermal plasma mills bacteria: Scanning electron microscopy observations

    SciTech Connect

    Lunov, O. Churpita, O.; Zablotskii, V.; Jäger, A.; Dejneka, A.; Deyneka, I. G.; Meshkovskii, I. K.; Syková, E.; Kubinová, Š.

    2015-02-02

    Non-thermal plasmas hold great promise for a variety of biomedical applications. To ensure safe clinical application of plasma, a rigorous analysis of plasma-induced effects on cell functions is required. Yet mechanisms of bacteria deactivation by non-thermal plasma remain largely unknown. We therefore analyzed the influence of low-temperature atmospheric plasma on Gram-positive and Gram-negative bacteria. Using scanning electron microscopy, we demonstrate that both Gram-positive and Gram-negative bacteria strains in a minute were completely destroyed by helium plasma. In contrast, mesenchymal stem cells (MSCs) were not affected by the same treatment. Furthermore, histopathological analysis of hematoxylin and eosin–stained rat skin sections from plasma–treated animals did not reveal any abnormalities in comparison to control ones. We discuss possible physical mechanisms leading to the shred of bacteria under non-thermal plasma irradiation. Our findings disclose how helium plasma destroys bacteria and demonstrates the safe use of plasma treatment for MSCs and skin cells, highlighting the favorability of plasma applications for chronic wound therapy.

  3. Energetic consequences of thermal and nonthermal food processing.

    PubMed

    Carmody, Rachel N; Weintraub, Gil S; Wrangham, Richard W

    2011-11-29

    Processing food extensively by thermal and nonthermal techniques is a unique and universal human practice. Food processing increases palatability and edibility and has been argued to increase energy gain. Although energy gain is a well-known effect from cooking starch-rich foods, the idea that cooking meat increases energy gain has never been tested. Moreover, the relative energetic advantages of cooking and nonthermal processing have not been assessed, whether for meat or starch-rich foods. Here, we describe a system for characterizing the energetic effects of cooking and nonthermal food processing. Using mice as a model, we show that cooking substantially increases the energy gained from meat, leading to elevations in body mass that are not attributable to differences in food intake or activity levels. The positive energetic effects of cooking were found to be superior to the effects of pounding in both meat and starch-rich tubers, a conclusion further supported by food preferences in fasted animals. Our results indicate significant contributions from cooking to both modern and ancestral human energy budgets. They also illuminate a weakness in current food labeling practices, which systematically overestimate the caloric potential of poorly processed foods. PMID:22065771

  4. Energetic consequences of thermal and nonthermal food processing

    PubMed Central

    Carmody, Rachel N.; Weintraub, Gil S.; Wrangham, Richard W.

    2011-01-01

    Processing food extensively by thermal and nonthermal techniques is a unique and universal human practice. Food processing increases palatability and edibility and has been argued to increase energy gain. Although energy gain is a well-known effect from cooking starch-rich foods, the idea that cooking meat increases energy gain has never been tested. Moreover, the relative energetic advantages of cooking and nonthermal processing have not been assessed, whether for meat or starch-rich foods. Here, we describe a system for characterizing the energetic effects of cooking and nonthermal food processing. Using mice as a model, we show that cooking substantially increases the energy gained from meat, leading to elevations in body mass that are not attributable to differences in food intake or activity levels. The positive energetic effects of cooking were found to be superior to the effects of pounding in both meat and starch-rich tubers, a conclusion further supported by food preferences in fasted animals. Our results indicate significant contributions from cooking to both modern and ancestral human energy budgets. They also illuminate a weakness in current food labeling practices, which systematically overestimate the caloric potential of poorly processed foods. PMID:22065771

  5. Tripled Readout Slices in Multi Time-Point pCASL Using Multiband Look-Locker EPI

    PubMed Central

    Zhang, Ke; Yun, Seong Dae; Shah, N. Jon

    2015-01-01

    Multi time-point pseudo-continuous arterial spin labelling (pCASL) with a Look-Locker EPI readout can sample the signal curve of blood kinetics at multiple time points after the labelling pulse. However, due to signal relaxation of labelled blood, the number of readout slices is limited. The aim of this study is to employ a multiband excitation technique to triple the number of readout slices in multi time-point pCASL. The multiband technique, along with 2-fold in-plane parallel imaging, was incorporated into the Look-Locker EPI for the multi time-point sampling of blood kinetic behaviour following the pCASL labelling scheme. The performance evaluation of the multiband and the single-band techniques were performed on four healthy subjects using a 32-channel head RF coil at 3T. Quantitative perfusion maps were analysed using a combination of labelling with and without flow suppression gradients. The perfusion maps provided by the multiband accelerated multi time-point pCASL were in good agreement with the conventional single-band technique. Multiband acceleration caused SNR loss but offered quantitative perfusion maps in 6.23 min with 18 slices compared with 6 slices within the same time period for the single-band method. As conclusion, the multiband technique can successfully triple the number of readout slices while achieving comparable perfusion data in the same measurement time as the conventional single-band readout. PMID:26544715

  6. Non-thermal Dupree diffusivity and shielding effects on atomic collisions in astrophysical turbulent plasmas

    NASA Astrophysics Data System (ADS)

    Lee, Myoung-Jae; Jung, Young-Dae

    2016-02-01

    The influence of non-thermal Dupree turbulence and the plasma shielding on the electron-ion collision is investigated in astrophysical non-thermal Lorentzian turbulent plasmas. The second-order eikonal analysis and the effective interaction potential including the Lorentzian far-field term are employed to obtain the eikonal scattering phase shift and the eikonal collision cross section as functions of the diffusion coefficient, impact parameter, collision energy, Debye length and spectral index of the astrophysical Lorentzian plasma. It is shown that the non-thermal effect suppresses the eikonal scattering phase shift. However, it enhances the eikonal collision cross section in astrophysical non-thermal turbulent plasmas. The effect of non-thermal turbulence on the eikonal atomic collision cross section is weakened with increasing collision energy. The variation of the atomic cross section due to the non-thermal Dupree turbulence is also discussed.

  7. Cylindrical and spherical ion acoustic waves in a plasma with nonthermal electrons and warm ions

    SciTech Connect

    Sahu, Biswajit; Roychoudhury, Rajkumar

    2005-05-15

    Using the reductive perturbation technique, nonlinear cylindrical and spherical Korteweg-de Vries (KdV) and modified KdV equations are derived for ion acoustic waves in an unmagnetized plasma consisting of warm adiabatic ions and nonthermal electrons. The effects of nonthermally distributed electrons on cylindrical and spherical ion acoustic waves are investigated. It is found that the nonthermality has a very significant effect on the nature of ion acoustic waves.

  8. Miniaturized Multi-Band Antenna via Element Collocation

    SciTech Connect

    Martin, R. P.

    2012-04-19

    Although much research has been performed on a driven element parasitically loaded by another element shorted to ground for dual frequency operation, the novel concept of two or more coplanar-driven elements in close proximity designed for multiple frequency operation has not been represented in the literature. Since each higher frequency antenna is built into the lower frequency elements, the largest element controls the structure’s total size. Furthermore, by using the self-resonant frequency inherent in reactive elements due to device packaging, the aperture of each antenna, due to a low insertion loss path at the frequency of the larger element, will include that of all smaller radiators. This configuration provides a large standing wave ratio at the shorter wavelengths via several series capacitive-inductive connections. Therefore, each antenna element provides the required surface area for the frequency of operation while being isolated from the larger radiators. For this study, a dual 2.45/5.8 GHz microstrip patch encompasses a small surface area of 9 square inches and provides circularly polarized electromagnetic radiation in excess of 6 dBi. This concept can be extrapolated to include additional radiators or may be scaled to other frequencies of interest.

  9. Effective Ginzburg-Landau free energy functional for multi-band isotropic superconductors

    NASA Astrophysics Data System (ADS)

    Grigorishin, Konstantin V.

    2016-04-01

    It has been shown that interband mixing of gradients of two order parameters (drag effect) in an isotropic bulk two-band superconductor plays important role - such a quantity of the intergradients coupling exists that the two-band superconductor is characterized with a single coherence length and a single Ginzburg-Landau (GL) parameter. Other quantities or neglecting of the drag effect lead to existence of two coherence lengths and dynamical instability due to violation of the phase relations between the order parameters. Thus so-called type-1.5 superconductors are impossible. An approximate method for solving of set of GL equations for a multi-band superconductor has been developed: using the result about the drag effect it has been shown that the free-energy functional for a multi-band superconductor can be reduced to the GL functional for an effective single-band superconductor.

  10. Comparison of multi-band period-luminosity relations for classical Cepheids in the Magellanic Clouds

    NASA Astrophysics Data System (ADS)

    Ngeow, Chow-Choong; Kanbur, Shashi M.

    2016-07-01

    The period-luminosity (PL) relation for classical fundamental mode Cepheids (hereafter Cepheids) is an important astrophysical tool in distance scale applications. Because of this, we initiated a program to derive multi-band PL relations with Cepheids in the Large and Small Magellanic Cloud (hereafter LMC and SMC, respectively), as there are ∼⃒ 103 Cepheids found in these two nearby galaxies. When compared the slopes of the multi-band PL relations for Cepheids in the LMC and SMC, we found that these PL slopes agree with each others except in the V and J band. We also found an excellent agreement of the PL slopes in Wesenheit function, hence we calibrated the Period-Wesenheit (PW) relation by combining the data from both Clouds, together with an accurate LMC distance based on measurement from late-type eclipsing binaries. Our calibrated Wesenheit function is MW = — 3.314 log(P) — 2.601.

  11. Evaluation of nine-frame enhanced multiband photography San Andreas fault zone, Carrizo Plain, California

    NASA Technical Reports Server (NTRS)

    Wallace, R. E.

    1969-01-01

    Nine-frame multiband aerial photography of a sample area 4500 feet on a side was processed to enhance spectral contrasts. The area concerned is in the Carrizo Plain, 45 miles west of Bakersfield, California, in sec. 29, T 31 S., R. 21 E., as shown on the Panorama Hills quadrangle topographic map published by the U. S. Geological Survey. The accompany illustrations include an index map showing the location of the Carrizo Plain area; a geologic map of the area based on field studies and examination of black and white aerial photographs; an enhanced multiband aerial photograph; an Aero Ektachrome photograph; black and white aerial photographs; and infrared image in the 8-13 micron band.

  12. Tunable multi-band chiral metamaterials based on double-layered asymmetric split ring resonators

    NASA Astrophysics Data System (ADS)

    Jia, Xiuli; Wang, Xiaoou; Meng, Qingxin; Zhou, Zhongxiang

    2016-07-01

    We have numerically demonstrated chiral metamaterials based on double-layered asymmetric Au film with hollow out design of split ring resonators on either side of the polyimide. Multiple electric dipoles and magnetic dipoles resulted from parallel and antiparallel currents between the eight split ring resonators. Multi-band circular dichroism is found in the visible frequency regime by studying the transmission properties. Huge optical activity and the induced multi-band negative refractive index are obtained at resonance by calculating the optical activity and ellipticity of the transmitted E-fields. Chirality parameter and effective refractive index are retrieved to illustrate the tunable optical properties of the metamaterials. The underlying mechanisms for the observed circular dichroism are analyzed. These metamaterials would offer flexible electromagnetic applications in the infrared and visible regime.

  13. Perturbative Approach to the Collective Modes in the TRSB Phase of Multiband Superconductors

    NASA Astrophysics Data System (ADS)

    Koyama, Tomio

    2016-06-01

    We develop a perturbative theory for the collective oscillation modes of the superconducting gaps in the time-reversal-symmetry-breaking (TRSB) phase of multiband superconductors. A perturbative series that has the pole singularity originating from the phase oscillation modes is constructed in general N-band systems with complex superconducting gaps so as to satisfy the Ward-Takahashi identity. We also present the perturbative series that leads to the singularity in the amplitude channel. Numerical results for the spectral functions of both phase and amplitude oscillation modes are given in a three-band case in which the TRSB phase appears. The perturbative series that brings about the Anderson-Higgs mechanism is also clarified in multiband charged superconductors.

  14. Multi-band polarization independent cylindrical metamaterial absorber and sensor application

    NASA Astrophysics Data System (ADS)

    Dincer, Furkan; Karaaslan, Muharrem; Colak, Sule; Tetik, Erkan; Akgol, Oguzhan; Altıntas, Olcay; Sabah, Cumali

    2016-03-01

    A multi-band perfect metamaterial absorber (MA) based on a cylindrical waveguide with polarization independency is numerically presented and investigated in detail. The proposed absorber has a very simple configuration, and it operates at flexible frequency ranges within the microwave frequency regime by simply tuning the dimensions of the structure. The maximum absorption values are obtained as 99.9%, 97.5%, 85.8%, 68.2% and 40.2% at the frequencies of 1.34 GHz, 2.15 GHz, 3.2 GHz, 4.31 GHz and 5.41 GHz, respectively. The numerical studies verify that the proposed model can provide multi-band perfect absorptions at wide polarization and incident angles due to its rotational symmetry feature. We have also realized sensor and parametric study applications in order to show additional features of the suggested model. The suggested MA enables myriad potential applications in medical technologies, sensors and in defense industry etc.

  15. Leggett modes and multiband superconductivity in Sr2RuO4

    NASA Astrophysics Data System (ADS)

    Huang, Wen; Scaffidi, Thomas; Sigrist, Manfred; Kallin, Catherine

    2016-08-01

    Sr2RuO4 is a prototypical multiband superconductor with three bands crossing the Fermi level. These bands exhibit distinct dimensional characteristics, with one quasi-2D γ band and two quasi-1D α and β bands. This leads to the expectation that the superconductivity on the γ band may be only weakly Josephson-coupled to that on the other two bands. Based on an explicit microscopic weak coupling calculation appropriate for Sr2RuO4 , we study the collective Leggett modes associated with the relative phase oscillations between the bands and show that a relatively soft Leggett mode exists due to the comparatively weaker interband Josephson coupling. These calculations also provide insight into why the superconducting gap magnitudes may be comparable on all three bands, despite the noticeable differences between the γ and α /β bands. The analyses can be readily applied to other multiband superconductors.

  16. EAM-based multiband OFDM systems incorporating PAPR reduction and SSII cancellation

    NASA Astrophysics Data System (ADS)

    Yang, Pengfei; Shi, Hu; Chen, Xue

    2016-04-01

    Multiband orthogonal frequency division multiplexing (OFDM) subcarrier allocation is a good scheme to fully utilize the available bandwidth under the restriction of dispersion- and chirp-induced power fading in electro-absorption modulator (EAM)-based intensity-modulation-direct-detection (IMDD) OFDM system. In this paper, a modified Tone Reservation (TR) technique combined with subcarrier interleaving is proposed to reduce high peak to average power ratio (PAPR) while minimizing the penalty of subcarrier-to-subcarrier intermixing interference. In the experiment, by incorporating of these two techniques, the receiver sensitivity is improved by about 1.8 dB when a 20 Gbps OFDM signal transmitted along 100 km long single mode fiber in an EAM-based multiband IMDD-OFDM system.

  17. A multiband THz bandpass filter based on multiple-resonance excitation of a composite metamaterial

    NASA Astrophysics Data System (ADS)

    Chen, Xu; Fan, Wen-Hui

    2015-05-01

    We present a systematic numerical study on a metal-dielectric-metal (MDM) sandwich structure for multiple resonance transmission in terahertz (THz) region. The designed structure consists of periodic square close ring array on both side of a flexible dielectric substrate, exhibits a multiband transmission, with low average insertion loss, steep skirts and high out-of-band rejection. In addition, due to its rotationally symmetric structure, this filter is polarization-insensitive for normal incidence of the electromagnetic waves, keeping highly transmission at a wide range of incident angles for transverse electric waves and transverse magnetic waves. The metamaterial structure can be utilized as a desirable multiband filter with many practical applications, especially for THz communication, spectroscopic detection and phase imaging.

  18. Waveguide transition with vacuum window for multiband dynamic nuclear polarization systems

    NASA Astrophysics Data System (ADS)

    Rybalko, Oleksandr; Bowen, Sean; Zhurbenko, Vitaliy; Ardenkjær-Larsen, Jan Henrik

    2016-05-01

    A low loss waveguide transition section and oversized microwave vacuum window covering several frequency bands (94 GHz, 140 GHz, 188 GHz) is presented. The transition is compact and was optimized for multiband Dynamic Nuclear Polarization (DNP) systems in a full-wave simulator. The window is more broadband than commercially available windows, which are usually optimized for single band operation. It is demonstrated that high-density polyethylene with urethane adhesive can be used as a low loss microwave vacuum window in multiband DNP systems. The overall assembly performance and dimensions are found using full-wave simulations. The practical aspects of the window implementation in the waveguide are discussed. To verify the design and simulation results, the window is tested experimentally at the three frequencies of interest.

  19. Broadband transient absorption study of photoexcitations in lead halide perovskites: Towards a multiband picture

    NASA Astrophysics Data System (ADS)

    Anand, Benoy; Sampat, Siddharth; Danilov, Evgeny O.; Peng, Weina; Rupich, Sara M.; Chabal, Yves J.; Gartstein, Yuri N.; Malko, Anton V.

    2016-04-01

    Ultrafast transient pump-probe measurements of thin CH3NH3PbI3 perovskite films over a wide spectral range from 350 to 800 nm reveal a family of photoinduced bleach (PB) and absorption (PA) features unequivocally pointing to the fundamentally multiband character of the underlying electronic structure. Excitation pump-energy dependent kinetics of three long-lived PB peaks at 1.65, 2.55, and 3.15 eV along with a broad PA band shows the involvement of band-edge thermalized carriers in all transitions and at least four, possibly more, electronic bands. The evolution of the transient signatures is described in terms of the redistribution of the conserved oscillator strength of the whole system. The multiband perspective opens up different directions for understanding and controlling photoexcitations in hybrid perovskites.

  20. Waveguide transition with vacuum window for multiband dynamic nuclear polarization systems.

    PubMed

    Rybalko, Oleksandr; Bowen, Sean; Zhurbenko, Vitaliy; Ardenkjær-Larsen, Jan Henrik

    2016-05-01

    A low loss waveguide transition section and oversized microwave vacuum window covering several frequency bands (94 GHz, 140 GHz, 188 GHz) is presented. The transition is compact and was optimized for multiband Dynamic Nuclear Polarization (DNP) systems in a full-wave simulator. The window is more broadband than commercially available windows, which are usually optimized for single band operation. It is demonstrated that high-density polyethylene with urethane adhesive can be used as a low loss microwave vacuum window in multiband DNP systems. The overall assembly performance and dimensions are found using full-wave simulations. The practical aspects of the window implementation in the waveguide are discussed. To verify the design and simulation results, the window is tested experimentally at the three frequencies of interest. PMID:27250449

  1. Multi-band silicon quantum dots embedded in an amorphous matrix of silicon carbide.

    PubMed

    Chang, Geng-rong; Ma, Fei; Ma, Da-yan; Xu, Ke-wei

    2010-11-19

    Silicon quantum dots embedded in an amorphous matrix of silicon carbide were realized by a magnetron co-sputtering process and post-annealing. X-ray photoelectron spectroscopy, glancing x-ray diffraction, Raman spectroscopy and high-resolution transmission electron microscopy were used to characterize the chemical composition and the microstructural properties. The results show that the sizes and size distribution of silicon quantum dots can be tuned by changing the annealing atmosphere and the atom ratio of silicon and carbon in the matrix. A physicochemical mechanism is proposed to demonstrate this formation process. Photoluminescence measurements indicate a multi-band configuration due to the quantum confinement effect of silicon quantum dots with different sizes. The PL spectra are further widened as a result of the existence of amorphous silicon quantum dots. This multi-band configuration would be extremely advantageous in improving the photoelectric conversion efficiency of photovoltaic solar cells. PMID:20975214

  2. Nonthermal effects of acceleration in the resonance interaction between two uniformly accelerated atoms

    NASA Astrophysics Data System (ADS)

    Rizzuto, Lucia; Lattuca, Margherita; Marino, Jamir; Noto, Antonio; Spagnolo, Salvatore; Zhou, Wenting; Passante, Roberto

    2016-07-01

    We study the resonance interaction between two uniformly accelerated identical atoms, one excited and the other in the ground state, prepared in a correlated (symmetric or antisymmetric) state and interacting with the scalar field or the electromagnetic field in the vacuum state. In this case (resonance interaction), the interatomic interaction is a second-order effect in the atom-field coupling. We separate the contributions of vacuum fluctuations and radiation reaction to the resonance energy shift of the system, and show that only radiation reaction contributes, while Unruh thermal fluctuations do not affect the resonance interaction. We also find that beyond a characteristic length scale related to the atomic acceleration, nonthermal effects in the radiation-reaction contribution change the distance dependence of the resonance interaction. Finally, we find that previously unidentified features appear, compared with the scalar field case, when the interaction with the electromagnetic field is considered, as a consequence of the peculiar nature of the vacuum quantum noise of the electromagnetic field in a relativistically accelerated background.

  3. Multi-band Differential Photometry of the Eclipsing Variable Star NSVS 5750160

    NASA Astrophysics Data System (ADS)

    Berrington, R. C.; Tuhey, E. M.

    2014-12-01

    We present new multi-band differential aperture photometry of the eclipsing variable star NSVS 5750160. The light curves are analyzed with the Wilson-Devinney model to determine best-fit stellar models. Our models show that NSVS 5750160 is consistent with a W-type W Ursae Majoris eclipsing variable star, and require the presence of a spot to fit the observed O’Connell effect. Two different spot models are presented but neither model is conclusive.

  4. Plasma motions and non-thermal line broadening in flaring twisted coronal loops

    NASA Astrophysics Data System (ADS)

    Gordovskyy, M.; Kontar, E. P.; Browning, P. K.

    2016-05-01

    Context. Observation of coronal extreme ultra-violet (EUV) spectral lines sensitive to different temperatures offers an opportunity to evaluate the thermal structure and flows in flaring atmospheres. This, in turn, can be used to estimate the partitioning between the thermal and kinetic energies released in flares. Aims: Our aim is to forward-model large-scale (50-10 000 km) velocity distributions to interpret non-thermal broadening of different spectral EUV lines observed in flares. The developed models allow us to understand the origin of the observed spectral line shifts and broadening, and link these features to particular physical phenomena in flaring atmospheres. Methods: We use ideal magnetohydrodynamics (MHD) to derive unstable twisted magnetic fluxtube configurations in a gravitationally stratified atmosphere. The evolution of these twisted fluxtubes is followed using resistive MHD with anomalous resistivity depending on the local density and temperature. The model also takes thermal conduction and radiative losses in the continuum into account. The model allows us to evaluate average velocities and velocity dispersions, which would be interpreted as non-thermal velocities in observations, at different temperatures for different parts of the models. Results: Our models show qualitative and quantitative agreement with observations. Thus, the line-of-sight (LOS) velocity dispersions demonstrate substantial correlation with the temperature, increasing from about 20-30 km s-1 around 1 MK to about 200-400 km s-1 near 10-20 MK. The average LOS velocities also correlate with velocity dispersions, although they demonstrate a very strong scattering compared to the observations. We also note that near footpoints the velocity dispersions across the magnetic field are systematically lower than those along the field. We conclude that the correlation between the flow velocities, velocity dispersions, and temperatures are likely to indicate that the same heating

  5. Non-Thermal Emission from the massive stellar association Cygnus OB2

    NASA Astrophysics Data System (ADS)

    Fenech, Danielle Marie; Prinja, Raman; Morford, Jack

    2015-08-01

    The Cygnus OB2 association is located in the Galactic Cygnus X region at a distance of 1.4 kpc, making it one of the closest young massive stellar clusters. Cyg OB2 is not only very rich in stellar density but also in its diversity. It is known to contain a rich population of massive stars including almost 2600 OB stars, a large number of binaries (including a collection of some of the most interesting radio emitting colliding-wind binaries), and a considerable number of pre-main sequence stars.We report here on the first results from The Cyg OB2 Radio Survey (COBRaS), which is a UCL-led e-MERLIN legacy project to provide a deep-field radio mapping of the Cygnus OB2 association. The project has been awarded a total allocation of 252 hours at C-band (5GHz) and 42 hours at L-band (1.6GHz) to image the core of the cluster.We discuss in particular the presence of non-thermal radio emission at 20 cm (L-band), and its potential as a highly efficient way to identify binaries via single-epoch observations, particularly for colliding-wind binaries. COBRaS data will provide a powerful tool for establishing binary incidence in Cyg~OB2, specifically in the difficult intermediate-period range (1--100~yr). Knowing the binary frequency over the whole period range is important for population synthesis.Additionally, Weak-lined T Tauri (WTT) stars in Cyg OB2 also emit non-thermal radiation from magnetically active regions. Hence these observations will be used to detect the considerable population of younger stars.Ultimately, we aim to assemble a substantial and uniquely sensitive radio dataset, which will be exploited to address several fundamentally important areas of stellar astrophysics, including mass-loss, binary frequency, stellar cluster dynamics, and triggered star-formation.

  6. A METHOD FOR INDIVIDUAL SOURCE BRIGHTNESS ESTIMATION IN SINGLE- AND MULTI-BAND DATA

    SciTech Connect

    Crawford, T. M.; Switzer, E. R.; Marrone, D. P.; Vieira, J. D.; Holzapfel, W. L.; Reichardt, C. L.

    2010-07-20

    We present a method of reliable extraction of the flux of individual sources from sky maps in the presence of noise and a source population in which number counts are a steeply falling function of flux. The method is an extension of a standard Bayesian procedure in the millimeter/submillimeter literature. As in the standard method, the prior applied to source flux measurements is derived from an estimate of the source counts as a function of flux, dN/dS. The key feature of the new method is that it enables reliable extraction of properties of individual sources, which previous methods in the literature do not. We first present the method for extracting individual source fluxes from data in a single observing band, then we extend the method to multiple bands, including prior information about the spectral behavior of the source population(s). The multi-band estimation technique is particularly relevant for classifying individual sources into populations according to their spectral behavior. We find that proper treatment of the correlated prior information between observing bands is key to avoiding significant biases in estimations of multi-band fluxes and spectral behavior, biases which lead to significant numbers of misclassified sources. We test the single- and multi-band versions of the method using simulated observations with observing parameters similar to that of the South Pole Telescope data used in Vieira et al.

  7. Fractionalizing the vortex lattice in multiband superconductors in the flux flow region

    NASA Astrophysics Data System (ADS)

    Lin, Shi-Zeng

    2014-03-01

    Because of the discovery of MgB2 and iron-based superconductors, multiband superconductors have attracted considerable attention recently. Multiband superconductors are not always straightforward extensions of the single-band counterpart, and novel features may arise. In multiband superconductors, electrons in different bands form distinct superfluid condensates, which are coupled to the same gauge field. Each condensate thus supports vortex excitation with fractional flux quantum. However the energy of a fractional vortex diverges logarithmically in the thermodynamic limit. In the ground state vortices in different bands are bounded and their normal cores are locked together to form a composite vortex with the standard integer quantum flux. It is interesting to ask whether the vortices in different condensates can decouple under certain conditions. In this talk, I will discuss the dissociation of the composite vortex lattice in the flux flow region when the disparity of superfluid density and coherence length between different bands is large. The fractional vortex lattice in different bands move with different velocities after the dissociation transition, and the dissociation transition shows up as an increase of flux flow resistivity. In the dissociated phase, the Shapiro steps are developed when an ac current is superimposed with a dc current. We also propose to stabilize the fractional vortices by periodic pinning arrays. This work was supported by the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering.

  8. Josephson systems based on ballistic point contacts between single-band and multi-band superconductors

    NASA Astrophysics Data System (ADS)

    Yerin, Y. S.; Kiyko, A. S.; Omelyanchouk, A. N.; Il'ichev, E.

    2015-11-01

    The Josephson effect in ballistic point contacts between single-band and multi-band superconductors was investigated. It was found that in the case of Josephson junctions formed by a single-band and an s±-wave two-band superconductor as well as by a single-band and a three-band superconductor the junctions become frustrated, showing the φ-contact properties. Depending on the ground state of a three-band superconductor with time-reversal symmetry breaking, the Josephson junction can have from one to three energy minima, some of which can be locally stable. We also study the behavior of a dc SQUID based on the Josephson junctions between single-band and multi-band superconductors. Some features on the dependences of the critical current and the total magnetic flux on the applied flux of a dc SQUID based on the Josephson point contacts between a single-band superconductor and an s±-wave superconductor, three-band superconductor with broken time-reversal symmetry and three-band superconductor without broken time-reversal symmetry as compared to the conventional dc SQUIDs based on single-band superconductors were found. The results can be used as an experimental tool to detect the existence of multi-band structure and time-reversal symmetry breaking.

  9. Miniaturized Multi-Band Antenna via Element Collocation

    SciTech Connect

    Martin, R P

    2012-06-01

    The resonant frequency of a microstrip patch antenna may be reduced through the addition of slots in the radiating element. Expanding upon this concept in favor of a significant reduction in the tuned width of the radiator, nearly 60% of the antenna metallization is removed, as seen in the top view of the antenna’s radiating element (shown in red, below, left). To facilitate an increase in the gain of the antenna, the radiator is suspended over the ground plane (green) by an air substrate at a height of 0.250" while being mechanically supported by 0.030" thick Rogers RO4003 laminate in the same profile as the element. Although the entire surface of the antenna (red) provides 2.45 GHz operation with insignificant negative effects on performance after material removal, the smaller square microstrip in the middle must be isolated from the additional aperture in order to afford higher frequency operation. A low insertion loss path centered at 2.45 GHz may simultaneously provide considerable attenuation at additional frequencies through the implementation of a series-parallel, resonant reactive path. However, an inductive reactance alone will not permit lower frequency energy to propagate across the intended discontinuity. To mitigate this, a capacitance is introduced in series with the inductor, generating a resonance at 2.45 GHz with minimum forward transmission loss. Four of these reactive pairs are placed between the coplanar elements as shown. Therefore, the aperture of the lower-frequency outer segment includes the smaller radiator while the higher frequency section is isolated from the additional material. In order to avoid cross-polarization losses due to the orientation of a transmitter or receiver in reference to the antenna, circular polarization is realized by a quadrature coupler for each collocated antenna as seen in the bottom view of the antenna (right). To generate electromagnetic radiation concentrically rotating about the direction of propagation

  10. Multi-band Monopole Antennas Loaded with Metamaterial TL

    NASA Astrophysics Data System (ADS)

    Song, Zhi-jie; Liang, Jian-gang

    2015-05-01

    A novel metamaterial transmission line (TL) by loading complementary single Archimedean spiral resonator pair (CSASRP) is investigated and used to design a set of multi-frequency monopole antennas. The particularity is that the CSASRP which features dual-shunt branches in the equivalent circuit model is directly etched in the signal strip. By smartly controlling the element parameters, three antennas are designed and one of them covering UMTS and Bluetooth bands is fabricated and measured. The antenna exhibits impedance matching better than -10 dB and normal monopolar radiation patterns at working bands of 1.9-2.22 and 2.38-2.5 GHz. Moreover, the loaded element also contributes to the radiation, which is the major advantage of this prescription over previous lumped-element loadings. The proposed antenna is also more compact over previous designs.

  11. Multi-band implications of external-IC flares

    NASA Astrophysics Data System (ADS)

    Richter, Stephan; Spanier, Felix

    2015-02-01

    Very fast variability on scales of minutes is regularly observed in Blazars. The assumption that these flares are emerging from the dominant emission zone of the very high energy (VHE) radiation within the jet challenges current acceleration and radiation models. In this work we use a spatially resolved and time dependent synchrotron-self-Compton (SSC) model that includes the full time dependence of Fermi-I acceleration. We use the (apparent) orphan γ -ray flare of Mrk501 during MJD 54952 and test various flare scenarios against the observed data. We find that a rapidly variable external radiation field can reproduce the high energy lightcurve best. However, the effect of the strong inverse Compton (IC) cooling on other bands and the X-ray observations are constraining the parameters to rather extreme ranges. Then again other scenarios would require parameters even more extreme or stronger physical constraints on the rise and decay of the source of the variability which might be in contradiction with constraints derived from the size of the black hole's ergosphere.

  12. Non-thermal plasma for inactivated-vaccine preparation.

    PubMed

    Wang, Guomin; Zhu, Ruihao; Yang, Licong; Wang, Kaile; Zhang, Qian; Su, Xia; Yang, Bing; Zhang, Jue; Fang, Jing

    2016-02-17

    Vaccines are of great importance in controlling the spread of infectious diseases in poultry farming. The safety and efficacy of vaccines are also essential. To explore the feasibility of a novel technology (non-thermal plasma) in inactivated vaccine preparation, an alternating current atmospheric pressure non-thermal plasma (NTP) jet with Ar/O2/N2 as the operating gas was used to inactivate a Newcastle disease virus (NDV, LaSota) strain and H9N2 avian influenza virus (AIV, A/Chicken/Hebei/WD/98) for vaccine preparation. The results showed that complete inactivation could be achieved with 2 min of NTP treatment for both NDV and AIV. Moreover, a proper NTP treatment time is needed for inactivation of a virus without destruction of the antigenic determinants. Compared to traditional formaldehyde-inactivated vaccine, the vaccine made from NDV treated by NTP for 2 min (NTP-2 min-NDV-vaccine) could induce a higher NDV-specific antibody titer in specific pathogen-free (SPF) chickens, and the results of a chicken challenge experiment showed that NTP-2 min-NDV-vaccine could protect SPF chickens from a lethal NDV challenge. Vaccines made from AIV treated by NTP for 2 min (NTP-2 min-AIV-vaccine) also showed a similar AIV-specific antibody titer compared with traditional AIV vaccines prepared using formaldehyde inactivation. Studies of the morphological changes of the virus, chemical analysis of NDV allantoic fluid and optical emission spectrum analysis of NTP suggested that reactive oxygen species and reactive nitrogen species produced by NTP played an important role in the virus inactivation process. All of these results demonstrated that it could be feasible to use non-thermal NTP as an alternative strategy to prepare inactivated vaccines for Newcastle disease and avian influenza. PMID:26529075

  13. Non-thermal Plasma for VOC Treatment in Flue Gases

    NASA Astrophysics Data System (ADS)

    Ikaunieks, Janis; Mezmale, Liga; Zandeckis, Aivars; Pubule, Jelena; Blumberga, Andra; Veidenbergs, Ivars

    2011-01-01

    The paper discusses non-thermal plasmas, their generation and characteristics, formation mechanisms of ozone and the treatment of volatile organic compounds (VOCs). In the experimental part, undecane (C11H24 as model VOCs) was treated with assistance of low temperature plasma at an atmospheric pressure which was generated in the so-called stack reactor. The gas composition was 13% of oxygen in nitrogen with impurities of carbon dioxide, carbon monoxide and undecane. The formation of by-products, as well as the removal efficiency, were investigated.

  14. Effects of nonthermal electrons on plasma expansion into vacuum

    SciTech Connect

    Bennaceur-Doumaz, D. Bara, D.; Benkhelifa, E.; Djebli, M.

    2015-01-28

    The expansion of semi-infinite plasma into vacuum is analyzed with a hydrodynamic model for cold ions assuming electrons modelled by a kappa-type distribution. Similarly to Mora study of a plasma expansion into vacuum [P. Mora, Phys. Rev. Lett. 90, 185002 (2003)], we formulated empirical expressions for the electric field strength, velocity, and position of the ion front in one-dimensional nonrelativistic, collisionless isothermally expanding plasma. Analytic expressions for the maximum ion energy and the spectrum of the accelerated ions in the plasma were derived and discussed to highlight the electron nonthermal effects on enhancing the ion acceleration in plasma expansion into vacuum.

  15. A new system of nonthermal filaments near the Galactic center

    NASA Technical Reports Server (NTRS)

    Bally, John; Yusef-Zadeh, Farhad

    1989-01-01

    The discovery of a new system of bright nonthermal filaments near the Galactic center is reported. This system is located in the interior of the western lobe of the Galactic center lobes and at the edge of a molecular cloud centered at V(LSR) of roughly -140 km/s in a relatively uncluttered field. The cloud has spectral lines about 50 km/s wide in (C-12)O, (C-13)O, and CS and a mass of order 100,000 solar.

  16. Nonthermal atoms in planetary, satellite, and cometary atmospheres

    NASA Astrophysics Data System (ADS)

    Kupperman, David Gerson

    1999-08-01

    The effect of nonthermal atoms is investigated in planetary, satellite, and cometary atmospheres. In the Earth's lower thermosphere, it is demonstrated that nonthermal N(4S) and O(3P) atoms increase the peak NO density, bringing closer model and observational (108 cm-3) densities. However, they are insufficient to remove the total NO deficit and only result in a peak NO density of approximately 3 × 107 cm-3 at 105 km. The loss of nonthermal N(4S) atoms from Titan and Triton are found to be 9 × 1024 and 1.5 × 1024 N atoms s-1, respectively. We find that the observational estimates of Strobel et al. [1992] are consistent with our modeling of escape from Titan. The loss of O atoms from Mars by nonthermal processes is a vital part of understanding the H2O and CO2 budgets in respect to how the Martian atmosphere has evolved. Anderson and Hord [1971] inferred the H escape flux to be approximately 1.8 × 108 cm -2 s-1 from Mariner 6 and 7 ultraviolet data. McElroy et al. [1977] initially calculated an 0 atom escape rate that was approximately half the H escape rate. However, with more sophisticated modeling this result was shown to be an order of magnitude too large [Lammer and Bauer, 1991; Fox, 1993; Luhmann, 1997]. In this work, we demonstrate that the O escape rate due to dissociative recombination of O2 + can be in stoichiometric balance with H escape over a solar cycle. Observations of comet Hale-Bopp reveal a third type of tail consisting of neutral sodium atoms. Using a point source of atomic sodium to model the observed tail, the sodium production is found to be 3.5 × 10 25 atoms s-1. This result suggests that the source of the sodium is either from the nucleus or inner coma. The production rates of water and carbon monoxide near perihelion are found to be 1031 s-1 and 2.7 × 1030 s-1 , respectively. The abundance of observed Na in the tail is inconsistent with cosmic abundances, suggesting that the majority of the sodium is trapped in the comet nucleus or

  17. Radiation

    NASA Video Gallery

    Outside the protective cocoon of Earth's atmosphere, the universe is full of harmful radiation. Astronauts who live and work in space are exposed not only to ultraviolet rays but also to space radi...

  18. Nonthermal inactivation of the norovirus surrogate tulane virus on blueberries using atmospheric cold plasma

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Viruses are currently the leading cause of foodborne outbreaks, most of which are associated with foods consumed raw. Cold plasma (CP) is an emerging novel nonthermal technology that can be used for the surface decontamination of foods. This study investigated CP technology for the nonthermal inacti...

  19. Description of recommended non-thermal mixed waste treatment technologies: Version 1.0

    SciTech Connect

    1995-08-01

    This document contains description of the technologies selected for inclusions in the Integrated Nonthermal Treatment Systems (INTS) Study. The purpose of these descriptions is to provide a more complete description of the INTS technologies. It supplements the summary descriptions of candidate nonthermal technologies that were considered for the INTS.

  20. Effects of nonthermal atmospheric cold plasma on blueberry native microbiota and sensory attributes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Nonthermal processing interventions are important steps in decontaminating and/or preserving fresh fruits, such as blueberries. Cold plasma (CP) is a novel nonthermal technology potentially useful in food processing settings. The objectives of this work were to determine CP reduction of blueberry ba...

  1. Effect Of Grain Size-Distribution And Nonthermal Ion Distribution On Dust Acoustic Solitons

    SciTech Connect

    Annou, K.; Annou, R.

    2005-10-31

    The investigation of the formation of non-linear coherent structures in dusty plasmas taking into account the dust size and non-thermal ion distributions is conducted. Conditions of the existence of solitons in terms of the Mach number, concentration of non-thermal ions, dust charge and the permeability of the grains are evaluated.

  2. Multiple-wavelength analysis of energy release during a solar flare - Thermal and nonthermal electron populations

    NASA Technical Reports Server (NTRS)

    Willson, Robert F.; Lang, Kenneth R.; Klein, Karl-Ludwig; Kerdraon, Alain; Trottet, Gerard

    1990-01-01

    Collaborative solar investigations by Tufts University and the Observatoire de Paris have resulted in simultaneous radio observations with the Very Large Array (VLA) and the Nancay Radioheliograph (NR), comparisons of this radio data with X-ray observations, and theoretical interpretations of the dominant radiation mechanisms during a weak impulsive solar flare observed on May 28, 1988. The VLA has mapped the flaring structures at time intervals of 3.3 s, showing that the preflash and flash-phase components of the impulsive emission originate in spatially separated sources. The 20.7 cm preflash source is ascribed to thermal gyroresonance emission from coronal loops with typical magnetic field strengths of up to 270 G; this emission is associated with heating and exhibits no detectable hard X-ray radiation above 30 keV. The flash-phase 20.7 cm source and the hard X-ray emission are attributed to nonthermal electrons in the coronal and chromospheric portions of a magnetic loop. The combination of imaging observations at 20.7 and 91.6 cm excludes emission from a confined hot plasma during the flash phase.

  3. Non-thermal mechanism of weak microwave fields influence on neurons

    NASA Astrophysics Data System (ADS)

    Shneider, M. N.; Pekker, M.

    2013-09-01

    A non-thermal mechanism of weak microwave field impact on a nerve fiber is proposed. It is shown that in the range of about 30-300 GHz, there are strongly pronounced resonances associated with the excitation of ultrasonic vibrations in the membrane as a result of interaction with electromagnetic radiation. The viscous dissipation limits the resonances and results in their broadening. These forced vibrations create acoustic pressure, which may lead to the redistribution of the protein transmembrane channels, and thus changing the threshold of the action potential excitation in the axons of the neural network. The influence of the electromagnetic microwave radiation on various specific areas of myelin nerve fibers was analyzed: the nodes of Ranvier, and the initial segment—the area between the neuron hillock and the first part of the axon covered with the myelin layer. It was shown that the initial segment is the most sensitive area of the myelined neurons from which the action potential normally starts.

  4. MERCURY OXIDIZATION IN NON-THERMAL PLASMA BARRIER DISCHARGE SYSTEM

    SciTech Connect

    V.K. Mathur

    2003-02-01

    In the past decade, the emission of toxic elements from human activities has become a matter of great public concern. Hg, As, Se and Cd typically volatilize during a combustion process and are not easily caught with conventional air pollution control techniques. In addition, there is no pollution prevention technique available now or likely be available in the foreseeable future that can prevent the emission of these trace elements. These trace elements pose additional scientific challenge as they are present at only ppb levels in large gas streams. Mercury, in particular, has attracted significant attention due to its high volatility, toxicity and potential threat to human health. In the present research work, a non-thermal plasma dielectric barrier discharge technique has been used to oxidize Hg{sup 0}(g) to HgO. The basic premise of this approach is that Hg{sup 0} in vapor form cannot be easily removed in an absorption tower whereas HgO as a particulate is amiable to water scrubbing. The work presented in this report consists of three steps: (1) setting-up of an experimental apparatus to generate mercury vapors at a constant rate and modifying the existing non-thermal plasma reactor system, (2) solving the analytical challenge for measuring mercury vapor concentration at ppb level, and (3) conducting experiments on mercury oxidation under plasma conditions to establish proof of concept.

  5. RXTE Observations M87: Investigating the Non-Thermal Continuum

    NASA Technical Reports Server (NTRS)

    Reynolds, Christopher S.

    2001-01-01

    This is the final report for NASA grant NAG5-7329, awarded for the RXTE Cycle 3 Guest Observer Program, "RXTE Observations of M87: Investigating the nonthermal continuum". This grant totaled $8000 and was spent over 3 years (4/1998-4/2001). It supported analysis of RXTE observations of the nearby giant elliptical galaxy M87 with the RXTE satellite. The main aim of these observations was to search for non-thermal emission from the core of M87 and the famous jet. This grant also partially funded supporting theoretical work. The observational campaign was performed in December 1997 and January 1998, and we were given the final data tape in April 1998. Sebastian Heinz (then a graduated student in our group) and I started to work on the data immediately. The results of our detailed analysis were submitted to the Astrophysical Journal in November 1998, and accepted for publication in March 1999. Tile paper was published in August, 1999. The journal reference is: A RXTE study of N187 and the core of the Virgo cluster, Reynolds C.S.,Heinx S., Fabian A.C., Begelman M.C., 1999, ApJ, 102, 1999. During this first year of the project, this grant supported Mr. Heinz's travel to the Paris Texas Symposium in December 1998, as well as providing funds for necessary maintenance of our computer system.

  6. RXTE Observations M87: Investigating the Non-Thermal Continuum

    NASA Astrophysics Data System (ADS)

    Reynolds, Christopher S.

    2001-01-01

    This is the final report for NASA grant NAG5-7329, awarded for the RXTE Cycle 3 Guest Observer Program, "RXTE Observations of M87: Investigating the nonthermal continuum". This grant totaled 8000 and was spent over 3 years (4/1998-4/2001). It supported analysis of RXTE observations of the nearby giant elliptical galaxy M87 with the RXTE satellite. The main aim of these observations was to search for non-thermal emission from the core of M87 and the famous jet. This grant also partially funded supporting theoretical work. The observational campaign was performed in December 1997 and January 1998, and we were given the final data tape in April 1998. Sebastian Heinz (then a graduated student in our group) and I started to work on the data immediately. The results of our detailed analysis were submitted to the Astrophysical Journal in November 1998, and accepted for publication in March 1999. Tile paper was published in August, 1999. The journal reference is: A RXTE study of N187 and the core of the Virgo cluster, Reynolds C.S.,Heinx S., Fabian A.C., Begelman M.C., 1999, ApJ, 102, 1999. During this first year of the project, this grant supported Mr. Heinz's travel to the Paris Texas Symposium in December 1998, as well as providing funds for necessary maintenance of our computer system.

  7. Effects of Non-thermal Electrons from ECCD on ECE Temperature Measurements for ITER

    NASA Astrophysics Data System (ADS)

    Subhash, P. V.; Pandya, Hitesh Kumar B.; Kumar, Ravinder; Vasu, P.

    2012-09-01

    In tokamaks, the radial temperature profile measured using Electron Cyclotron Emission (ECE) diagnostics are affected by many phenomena like harmonics overlap, relativistic down shifting, presence of non-thermals etc. In this paper we have estimated effects of a small non-thermal electron population on measured temperature profile for ITER-Scenario 2. For ITER like plasma, radial temperature profiles can be obtained from the second harmonic ECE spectrum. It is possible that, higher harmonics produced from the non-thermals can be relativistically downshifted to second harmonics and introduce error in the measured temperature profile. Generally Non-thermals are produced from Electron Cyclotron Resonance heating (ECRH), Electron Cyclotron Current Drive (ECCD) etc. In the present study the non-thermals are assumed to be produced from proposed ECCD, which is being considered for suppressing Neoclassical Tearing Modes (NTM). We have ignored any other source of non-thermals in the present study. All the numerical calculations reported in this paper is performed using NOTEC computer code which is capable of handling non-thermal populations. The locations and spatial extents of non-thermals are taken from previous report on optimization study of the ITER ECRH top launcher. The non-thermals are assumed to be centered around safety points q=1, q=1.5 and q=2, where the ECCD is expected to be used for suppressing the NTMs. The main results of the present study are summarized below. In the first part of the paper we present the results for temperature measurement with out non-thermal populations for the purpose of validation. Secondly the rage of higher harmonic frequencies (due to nonthermals) which possibly reach antenna and induce error in the temperature measurement are identified and the corresponding energies of non-thermal populations are calculated analytically. This calculations are further checked by simulations using NOTEC code. Finally non-thermal populations are

  8. Non-thermal shielding effects on the Compton scattering power in astrophysical plasmas

    NASA Astrophysics Data System (ADS)

    Shin, Dong-Soo; Jung, Young-Dae

    2015-10-01

    The non-thermal shielding effects on the inverse Compton scattering are investigated in astrophysical non-thermal Lorentzian plasmas. The inverse Compton power is obtained by the modified Compton scattering cross section in Lorentzian plasmas with the blackbody photon distribution. The total Compton power is also obtained by the Lorentzan distribution of plasmas. It is found that the influence of non-thermal character of the plasma suppresses the inverse Compton power in astrophysical Lorentzian plasmas. It is also found that the non-thermal effect on the inverse Compton power decreases with an increase of the temperature. In addition, the non-thermal effect on the total Compton power with Lorentzan plasmas increases in low-temperature photons and, however, decreases in intermediate-temperature photons with increasing Debye length. The variation of the total Compton power is also discussed.

  9. Multiband photometry of Comets Kohoutek, Bennett, Bradfield, and Encke

    NASA Technical Reports Server (NTRS)

    Ney, E. P.

    1974-01-01

    Observations of Comets Kohoutek (1973f), Bradfield (1974b), and P/Encke have been made at a number of wavelengths between 0.55 and 18 microns. The silicate feature first observed in Comet Bennett (1969i) seems to be a common characteristic of cometary material. The comas of these comets radiate infrared with an effective temperature higher than the black-body temperature at the given distance from the sun. The albedo of the dust particles is between 0.10 and 0.20. The particles in the coma and tail are small, but the particles in the anti-tail of Comet Kohoutek must be larger than about 10 microns diameter. The observations give an absolute upper limit to the diameter of Comet Kohoutek of 30 km. A consistent interpretation would indicate that Comets Kohoutek and Bradfield have nuclear diameters of 5 to 10 km, that Bennett was several times larger, and that P/Encke is 10 times smaller. The peculiar behavior of Bradfield showed that the coma of a single comet can abruptly change its dust composition.

  10. Clinically feasible NODDI characterization of glioma using multiband EPI at 7 T

    PubMed Central

    Wen, Qiuting; Kelley, Douglas A.C.; Banerjee, Suchandrima; Lupo, Janine M.; Chang, Susan M.; Xu, Duan; Hess, Christopher P.; Nelson, Sarah J.

    2015-01-01

    Recent technological progress in the multiband echo planer imaging (MB EPI) technique enables accelerated MR diffusion weighted imaging (DWI) and allows whole brain, multi-b-value diffusion imaging to be acquired within a clinically feasible time. However, its applications at 7 T have been limited due to B1 field inhomogeneity and increased susceptibility artifact. It is an ongoing debate whether DWI at 7 T can be performed properly in patients, and a systematic SNR comparison for multiband spin-echo EPI between 3 T and 7 T has not been methodically studied. The goal of this study was to use MB EPI at 7 T in order to obtain 90-directional multi-shell DWI within a clinically feasible acquisition time for patients with glioma. This study included an SNR comparison between 3 T and 7 T, and the application of B1 mapping and distortion correction procedures for reducing the impact of variations in B0 and B1. The optimized multiband sequence was applied in 20 patients with glioma to generate both DTI and NODDI maps for comparison of values in tumor and normal appearing white matter (NAWM). Our SNR analysis showed that MB EPI at 7 T was comparable to that at 3 T, and the data quality acquired in patients was clinically acceptable. NODDI maps provided unique contrast within the T2 lesion that was not seen in anatomical images or DTI maps. Such contrast may reflect the complexity of tissue compositions associated with disease progression and treatment effects. The ability to consistently obtain high quality diffusion data at 7 T will contribute towards the implementation of a comprehensive brain MRI examination at ultra-high field. PMID:26509116

  11. The Composition of the Lunar Crust as Revealed by the Study of Impact Basin Rings using the Kaguya Multiband Imager

    NASA Astrophysics Data System (ADS)

    Lemelin, M.; Lucey, P. G.; Gaddis, L. R.; Miljkovic, K.

    2015-12-01

    Impact basins excavate material from below the lunar surface and expose it on their peak rings. Peak rings can thus be used as probes to study the composition of the lunar crust with depth, which can in turn be compared to models of the formation of the lunar crust. Global surveys conducted to find exposures of nearly pure minerals have found rare lithologies such as norites, troctolites, and anorthosites associated with many basins rings [Yamamoto et al., 2010; 2012, Nakamura et al., 2012], but the abundance of these lithologies relative to the rings as a whole was not determined. Taking a comprehensive approach, Cheek et al. [2013] found that every immature exposure in the inner rook ring of the Orientale basin consists of anorthosite, suggesting that a massive layer of anorthosite is present at the Orientale target site. In this study, we take the approach of Cheek et al. [2013] and examine all the immature exposures in the rings of 14 impact basins. We use Multiband Imager (415-1550 nm) data and radiative transfer modeling to quantify the abundance of the four major lunar minerals in the inner ring of these basins, and determine the dominant lithologies exposed by the rings. We identify the inner ring of these basins using GRAIL crustal thickness data, and derived the mineralogy at a spatial resolution of 80 meters per pixel. Our preliminary results indicate that the dominant lithology in the inner ring of 12 of the 14 basins is anorthosite, with modal plagioclase content ranging between 92-94 wt%, suggesting that a massive layer of anorthosite is widespread under the lunar surface. The dominant lithologies in the other two basins are noritic and gabbroic anorthosites. The other lithologies present in the 14 basins will be investigated next, and the depth of excavation of each of these basin rings as well as the crustal thickness at these sites will be used to determine the composition of the crust with depth.

  12. Fiber-optic multiband radiometer for online measurements of near room temperature and emissivity.

    PubMed

    Uman, Igor; Katzir, Abraham

    2006-02-01

    A multiband infrared fiber-optic radiometer was developed for online near room temperature and emissivity measurements. Real time measurements were carried out on gray and selective bodies at near room temperature. The mean accuracy obtained for the body temperature was roughly 1 degrees C and for emissivity was roughly 0.03. The radiometer is capable of performing measurements without prior knowledge of the body emissivity. Incorporation of fiber optics allows one to perform measurements without a clear line of sight between the radiometer and the body. This radiometer will have important applications in biology, electronics, and other areas. PMID:16480197

  13. Isotope effect on electron-phonon interaction in the multiband superconductor MgB2

    NASA Astrophysics Data System (ADS)

    Mou, Daixiang; Manni, Soham; Taufour, Valentin; Wu, Yun; Huang, Lunan; Bud'ko, S. L.; Canfield, P. C.; Kaminski, Adam

    2016-04-01

    We investigate the effect of isotope substitution on the electron-phonon interaction in the multiband superconductor MgB2 using tunable laser-based angle-resolved photoemission spectroscopy. The kink structure around 70 meV in the σ band, which is caused by electron coupling to the E2 g phonon mode, is shifted to higher binding energy by ˜3.5 meV in Mg 10B2 and the shift is not affected by superconducting transition. These results serve as the benchmark for investigations of isotope effects in known, unconventional superconductors and newly discovered superconductors where the origin of pairing is unknown.

  14. Investigation of dust properties within the Ophiuchus region with multi-band observations

    NASA Astrophysics Data System (ADS)

    Lee, D. H.; Jeong, W. S.; Pyo, J.; Seon, K. I.

    2011-05-01

    We present the multi-band images of the Ophiuchus molecular cloud region to investigate the physical properties of dust. Based on the far-ultraviolet (FUV; 1370 - 1670 A) image, observed with the SPEAR imaging spectrograph, we generate a model that gives the properties of the dust grains (such as albedo and asymmetry factor) in the cloud. With the obtained FUV intensity map, we combine the Spitzer MIPS and the Akari FIS observations to produce a dust temperature map and a far-IR (FIR) dust opacity map for further analysis of dust evolution.

  15. Isotope effect on electron-phonon interaction in the multiband superconductor MgB2

    DOE PAGESBeta

    Mou, Daixiang; Manni, Soham; Taufour, Valentin; Wu, Yun; Huang, Lunan; Bud'ko, S. L.; Canfield, P. C.; Kaminski, Adam

    2016-04-07

    We investigate the effect of isotope substitution on the electron-phonon interaction in the multiband superconductor MgB2 using tunable laser-based angle-resolved photoemission spectroscopy. The kink structure around 70 meV in the σ band, which is caused by electron coupling to the E2g phonon mode, is shifted to higher binding energy by ~3.5 meV in Mg10B2 and the shift is not affected by superconducting transition. Furthermore, these results serve as the benchmark for investigations of isotope effects in known, unconventional superconductors and newly discovered superconductors where the origin of pairing is unknown.

  16. PSF homogenization for multi-band photometry from space on extended objects

    NASA Astrophysics Data System (ADS)

    Boucaud, A.; Dole, H.; Abergel, A.; Ayasso, H.; Orieux, F.

    2016-09-01

    We present a fast and robust tool to create PSF matching kernels for multi-band photometric studies. Such kernels are useful for convolving images down to the same PSF prior to computing flux measurements like aperture photometry or spectral fitting. Unlike similar existing methods, we use a Wiener filter to take into account the real shape of the effective PSF, usually very complex for space telescopes. We apply this scheme to Euclid simulated PSF images to demonstrate the efficiency of the algorithm. This tool is publicly available http://www.github.io/aboucaud/pypher.

  17. NIMBUS: A Near-Infrared Multi-Band Ultraprecise Spectroimager for SOFIA

    NASA Technical Reports Server (NTRS)

    McElwain, Michael W.; Mandell, Avi; Woodgate, Bruce E.; Spiegel, David S.; Madhusudhan, Nikku; Amatucci, Edward; Blake, Cullen; Budinoff, Jason; Burgasser, Adam; Burrows, Adam; Clampin, Mark C.; Conroy, Charlie; Deming, L. Drake; Dunham, Edward; Foltz, Roger; Gong, Qian; Knutson, Heather; Muench, Theodore; Murray-Clay, Ruth; Peabody, Hume; Rauscher, Bernard J.; Rinehart, Stephen A.; Villanueva, Geronimo

    2012-01-01

    We present a new and innovative near-infrared multi-band ultraprecise spectroimager (NIMBUS) for SOFIA. This instrument will enable many exciting observations in the new age of precision astronomy. This optical design splits the beam into 8 separate spectral bandpasses, centered around key molecular bands from 1 to 4 microns. Each spectral channel has a wide field of view for simultaneous observations of a reference star that can decorrelate time-variable atmospheric and optical assembly effects, allowing the instrument to achieve ultraprecise photometry for a wide variety of astrophysical sources

  18. Multi-band asymmetric acoustic transmission in a bended waveguide with multiple mechanisms

    NASA Astrophysics Data System (ADS)

    Huang, Yu-lei; Sun, Hong-xiang; Xia, Jian-ping; Yuan, Shou-qi; Ding, Xin-lei

    2016-07-01

    We report the realization of a multi-band device of the asymmetric acoustic transmission by placing a phononic crystal inside a bended waveguide immersed in water, as determined both experimentally and numerically. The asymmetric acoustic transmission exists in three frequency bands below 500 kHz induced by multiple mechanisms. Besides the band gap of the phononic crystal, we also introduce the deaf mode and interaction between the phononic crystal and waveguide. More importantly, this asymmetric transmission can be systematically controlled by mechanically rotating the square rods of the phononic crystal. The device has the advantages of multiple band, broader bandwidth, and adjustable property, showing promising applications in ultrasonic devices.

  19. Non-thermal radio emission from colliding flows in classical nova V1723 Aql

    NASA Astrophysics Data System (ADS)

    Weston, Jennifer H. S.; Sokoloski, J. L.; Metzger, Brian D.; Zheng, Yong; Chomiuk, Laura; Krauss, Miriam I.; Linford, Justin D.; Nelson, Thomas; Mioduszewski, Amy J.; Rupen, Michael P.; Finzell, Tom; Mukai, Koji

    2016-03-01

    The importance of shocks in nova explosions has been highlighted by Fermi's discovery of γ-ray-producing novae. Over three years of multiband Very Large Array radio observations of the 2010 nova V1723 Aql show that shocks between fast and slow flows within the ejecta led to the acceleration of particles and the production of synchrotron radiation. Soon after the start of the eruption, shocks in the ejecta produced an unexpected radio flare, resulting in a multipeaked radio light curve. The emission eventually became consistent with an expanding thermal remnant with mass 2 × 10-4 M⊙ and temperature 104 K. However, during the first two months, the ≳106 K brightness temperature at low frequencies was too high to be due to thermal emission from the small amount of X-ray-producing shock-heated gas. Radio imaging showed structures with velocities of 400 km s-1 (d/6 kpc) in the plane of the sky, perpendicular to a more elongated 1500 km s-1 (d/6 kpc) flow. The morpho-kinematic structure of the ejecta from V1723 Aql appears similar to nova V959 Mon, where collisions between a slow torus and a faster flow collimated the fast flow and gave rise to γ-ray-producing shocks. Optical spectroscopy and X-ray observations of V1723 Aql during the radio flare are consistent with this picture. Our observations support the idea that shocks in novae occur when a fast flow collides with a slow collimating torus. Such shocks could be responsible for hard X-ray emission, γ-ray production, and double-peaked radio light curves from some classical novae.

  20. Nonthermal dark matter and the top polarization at collider

    NASA Astrophysics Data System (ADS)

    Gao, Yu

    2016-06-01

    We discuss the characteristic collider signatures, in particular a highly polarized resonant single-top channel for a minimal color triplet extension to the Standard Model. This extension provides baryogensis and a non-thermal production history of a dark matter candidate. We further discuss the implementation of both completely left and right-handed chiral interaction in the model and the difference in phenomenology between the two scenarios. If the color triplets are isospin singlets, the dark matter candidate mass is 1 GeV and the single-top quarks are strictly right-handed polarized. Alternatively, the isospin-doublet color triplets lead to strictly left-handed single top events and a more extended particle spectrum.

  1. Efficacy of Nonthermal Atmospheric Pressure Plasma for Tooth Bleaching

    PubMed Central

    Nam, Seoul Hee; Lee, Hae June; Hong, Jin Woo; Kim, Gyoo Cheon

    2015-01-01

    The conventional light source used for tooth bleaching has the potential to cause thermal damage, and the actual role of the light source is doubtful. In this study, we evaluated bleaching efficacy, temperature, and morphological safety after tooth bleaching with nonthermal atmospheric pressure plasma. Tooth bleaching combined with plasma had improved efficacy in providing a higher level of brightness. The temperature of the pulp chamber was maintained around 37°C, indicating that the plasma does not cause any thermal damage. The morphological results of tooth bleaching with plasma did not affect mineral composition under scanning electron microscopy (SEM) observations. On the basis of these results, the application of plasma and low concentration of 15% carbamide peroxide (CP) has a high capability for effective tooth bleaching. It can be documented that plasma is a safe energe source, which has no deleterious effects on the tooth surface. PMID:25685843

  2. Neptune's non-thermal radio emissions - Phenomenology and source locations

    NASA Technical Reports Server (NTRS)

    Rabl, Gerald K. F.; Ladreiter, H.-P.; Rucker, Helmut O.; Kaiser, Michael L.

    1992-01-01

    During the inbound and the outbound leg of Voyager 2's encounter with Neptune, the Planetary Radio Astronomy (PRA) experiment aboard the spacecraft detected short radio bursts at frequencies within the range of about 500-1300 kHz, and broad-banded smoothly varying emission patterns within the frequency range from about 40-800 kHz. Both emissions can be described in terms of a period of 16.1 hours determining Neptune's rotation period. Furthermore, just near closest approach, a narrow-banded smoothly varying radio component was observed occurring between 600 and 800 kHz. After giving a brief overview about some general characteristics of Neptune's nonthermal radio emission, the source locations of Neptune's emission components are determined, using an offset tilted dipole model for Neptune's magnetic field. Assuming that the emission originates near the electron gyrofrequency a geometrical beaming model is developed in order to fit the observed emission episodes.

  3. Nonthermal plasma--A tool for decontamination and disinfection.

    PubMed

    Scholtz, Vladimir; Pazlarova, Jarmila; Souskova, Hana; Khun, Josef; Julak, Jaroslav

    2015-11-01

    By definition, the nonthermal plasma (NTP) is partially ionized gas where the energy is stored mostly in the free electrons and the overall temperature remains low. NTP is widely used for many years in various applications such as low-temperature plasma chemistry, removal of gaseous pollutants, in gas-discharge lamps or surface modification. However, during the last ten years, NTP usage expanded to new biological areas of application like plasma microorganisms' inactivation, ready-to-eat food preparation, biofilm degradation or in healthcare, where it seems to be important for the treatment of cancer cells and in the initiation of apoptosis, prion inactivation, prevention of nosocomial infections or in the therapy of infected wounds. These areas are presented and documented in this paper as a review of representative publications. PMID:25595663

  4. Frequency Stratification of the Nonthermal Emission in Blazars

    NASA Technical Reports Server (NTRS)

    Marscher, Alan P.

    2001-01-01

    Research supported by this grant involved theoretical investigations of the multifrequency nonthermal emission from the relativistic jets in blazars, which are quasars and related objects with highly variable brightness. In the initial stage of the project, one-dimensional, conical (i.e., spherical symmetry between the jet axis and surface is assumed) jet models were used to explain the multi-waveband spectra and variability of blazars. The results were applied to two flares observed in the object PKS 2155-304, leading to the conclusion that the distinct differences in the observed characteristics of the two flares can be explained with the same jet model if two different physical parameters (the magnetic field in the first flare and the efficiency of acceleration of electrons to high energies in the second) varied.

  5. Fluctuation theorem in driven nonthermal systems with quenched disorder

    SciTech Connect

    Reichhardt, Charles; Reichhardt, C J; Drocco, J A

    2009-01-01

    We demonstrate that the fluctuation theorem of Evans and Searles can be used to characterize the class of dynamics that arises in nonthermal systems of collectively interacting particles driven over random quenched disorder. By observing the frequency of entropy-destroying trajectories, we show that there are specific dynamical regimes near depinning in which this theorem holds. Hence the fluctuation theorem can be used to characterize a significantly wider class of non-equilibrium systems than previously considered. We discuss how the fluctuation theorem could be tested in specific systems where noisy dynamics appear at the transition from a pinned to a moving phase such as in vortices in type-II superconductors, magnetic domain walls, and dislocation dynamics.

  6. Numerical Simulation of Non-Thermal Food Preservation

    NASA Astrophysics Data System (ADS)

    Rauh, C.; Krauss, J.; Ertunc, Ö.; Delgado, a.

    2010-09-01

    Food preservation is an important process step in food technology regarding product safety and product quality. Novel preservation techniques are currently developed, that aim at improved sensory and nutritional value but comparable safety than in conventional thermal preservation techniques. These novel non-thermal food preservation techniques are based for example on high pressures up to one GPa or pulsed electric fields. in literature studies the high potential of high pressures (HP) and of pulsed electric fields (PEF) is shown due to their high retention of valuable food components as vitamins and flavour and selective inactivation of spoiling enzymes and microorganisms. for the design of preservation processes based on the non-thermal techniques it is crucial to predict the effect of high pressure and pulsed electric fields on the food components and on the spoiling enzymes and microorganisms locally and time-dependent in the treated product. Homogenous process conditions (especially of temperature fields in HP and PEF processing and of electric fields in PEF) are aimed at to avoid the need of over-processing and the connected quality loss and to minimize safety risks due to under-processing. the present contribution presents numerical simulations of thermofluiddynamical phenomena inside of high pressure autoclaves and pulsed electric field treatment chambers. in PEF processing additionally the electric fields are considered. Implementing kinetics of occurring (bio-) chemical reactions in the numerical simulations of the temperature, flow and electric fields enables the evaluation of the process homogeneity and efficiency connected to different process parameters of the preservation techniques. Suggestions to achieve safe and high quality products are concluded out of the numerical results.

  7. RELATIVISTIC RECONNECTION: AN EFFICIENT SOURCE OF NON-THERMAL PARTICLES

    SciTech Connect

    Sironi, Lorenzo; Spitkovsky, Anatoly E-mail: anatoly@astro.princeton.edu

    2014-03-01

    In magnetized astrophysical outflows, the dissipation of field energy into particle energy via magnetic reconnection is often invoked to explain the observed non-thermal signatures. By means of two- and three-dimensional particle-in-cell simulations, we investigate anti-parallel reconnection in magnetically dominated electron-positron plasmas. Our simulations extend to unprecedentedly long temporal and spatial scales, so we can capture the asymptotic state of the system beyond the initial transients, and without any artificial limitation by the boundary conditions. At late times, the reconnection layer is organized into a chain of large magnetic islands connected by thin X-lines. The plasmoid instability further fragments each X-line into a series of smaller islands, separated by X-points. At the X-points, the particles become unmagnetized and they get accelerated along the reconnection electric field. We provide definitive evidence that the late-time particle spectrum integrated over the whole reconnection region is a power law whose slope is harder than –2 for magnetizations σ ≳ 10. Efficient particle acceleration to non-thermal energies is a generic by-product of the long-term evolution of relativistic reconnection in both two and three dimensions. In three dimensions, the drift-kink mode corrugates the reconnection layer at early times, but the long-term evolution is controlled by the plasmoid instability which facilitates efficient particle acceleration, analogous to the two-dimensional physics. Our findings have important implications for the generation of hard photon spectra in pulsar winds and relativistic astrophysical jets.

  8. Weakly nonlinear dust ion-acoustic shock waves in a dusty plasma with nonthermal electrons

    SciTech Connect

    Berbri, Abderrezak; Tribeche, Mouloud

    2009-05-15

    Weakly nonlinear dust ion-acoustic (DIA) shock waves are investigated in a dusty plasma with nonthermal electrons. A modified Korteweg-de Vries equation with a cubic nonlinearity is derived. Due to the net negative dust charge {mu}Z{sub d} and electron nonthermality, the present plasma model can admit compressive and rarefactive weak DIA shock waves. The effect of increasing {mu}Z{sub d} is to lower the critical nonthermal parameter {beta}{sub c} above which only rarefactive DIA shock waves are admitted. Our investigation may help to understand the nonlinear structures observed in the auroral acceleration regions.

  9. Large amplitude double layers in a positively charged dusty plasma with nonthermal electrons

    SciTech Connect

    Djebli, M.; Marif, H.

    2009-06-15

    A pseudopotential approach is used to investigate large amplitude dust-acoustic solitary structures for a plasma composed of positively charged dust, cold electrons, and nonthermal hot electrons. Numerical investigation for an adiabatic situation is conducted to examine the existence region of the wave. The negative potential of the double layers is found to be dependent on nonthermal parameters, Mach number, and electrons temperature. A range of the nonthermal parameters values exists for which two possible double layers for the same plasma mix at different Mach numbers and with significant different amplitudes. The present model is used to investigate localized structures in the lower-altitude Earth's ionosphere.

  10. NATO Advanced Research Workshop on Non-Thermal Plasma Techniques for Pollution Control

    NASA Astrophysics Data System (ADS)

    1992-09-01

    Acid rain, global warming, ozone depletion, and smog are preeminent environmental problems facing the world today. Non-thermal plasma techniques offer an innovative approach to the cost-effective solution of these problems. Many potential applications of non-thermal plasmas to air pollution control have already been demonstrated. On 21-25 Sept. 1992, leading experts from academia, government laboratories, and industry met at Cambridge University, England to discuss laboratory studies and industrial implementation of non-thermal plasmas for the abatement of hazardous gaseous wastes. Papers presented at the workshop are included.

  11. Disk-Corona Model of Active Galactic Nuclei with Nonthermal Pairs

    NASA Technical Reports Server (NTRS)

    Tsuruta, Sachiko; Kellen, Michael

    1995-01-01

    As a promising model for the X-ray emission from radio-quiet quasars and Seyfert 1 nuclei, we present a nonthermal disk-corona model, where soft photons from a disk are Comptonized by the nonthermal electron-positron pairs in a coronal region above the disk. Various characteristics of our model are qualitatively similar to the homogeneous, spherical, nonthermal pair models previously studied, but the important difference is that in our disk-corona model gamma-ray depletion is far more efficient, and, moreover, the gamma-ray annihilation line is much less prominent. Consequently, this model naturally satisfies the observed constraints on active galactic nuclei.

  12. Quantum radiation of general nonstationary black holes

    NASA Astrophysics Data System (ADS)

    Hua, Jia-Chen; Huang, Yong-Chang

    2009-02-01

    Quantum radiation of general nonstationary black holes is investigated by using the method of generalized tortoise-coordinate transformation (GTT). It is shown in general that the temperature and the shape of the event horizon of this kind of black holes depend on time and angle. Further, we find that the chemical potential in the thermal-radiation spectrum is equal to the highest energy of the negative-energy state of particles in nonthermal radiation for general nonstationary black holes.

  13. FIR filters for hardware-based real-time multi-band image blending

    NASA Astrophysics Data System (ADS)

    Popovic, Vladan; Leblebici, Yusuf

    2015-02-01

    Creating panoramic images has become a popular feature in modern smart phones, tablets, and digital cameras. A user can create a 360 degree field-of-view photograph from only several images. Quality of the resulting image is related to the number of source images, their brightness, and the used algorithm for their stitching and blending. One of the algorithms that provides excellent results in terms of background color uniformity and reduction of ghosting artifacts is the multi-band blending. The algorithm relies on decomposition of image into multiple frequency bands using dyadic filter bank. Hence, the results are also highly dependant on the used filter bank. In this paper we analyze performance of the FIR filters used for multi-band blending. We present a set of five filters that showed the best results in both literature and our experiments. The set includes Gaussian filter, biorthogonal wavelets, and custom-designed maximally flat and equiripple FIR filters. The presented results of filter comparison are based on several no-reference metrics for image quality. We conclude that 5/3 biorthogonal wavelet produces the best result in average, especially when its short length is considered. Furthermore, we propose a real-time FPGA implementation of the blending algorithm, using 2D non-separable systolic filtering scheme. Its pipeline architecture does not require hardware multipliers and it is able to achieve very high operating frequencies. The implemented system is able to process 91 fps for 1080p (1920×1080) image resolution.

  14. Identifying detrimental effects for multi-band superconductivity - Application to Sr2RuO4

    NASA Astrophysics Data System (ADS)

    Ramires, Aline; Sigrist, Manfred

    Spin polarization and anti-symmetric spin-orbit coupling are detrimental to Cooper pairing in the spin singlet and spin triplet channel, respectively. These are the well-known features of paramagnetic limiting and selection rules in non-centrosymmetric superconductors. We propose a general scheme to probe the compatibility of arbitrary pairing states with given normal state properties in model systems. This yields a universal criterion which we validate with results based on weak coupling analysis of the stability of different superconducting gaps under time-reversal and inversion symmetry breaking fields. Our criterion does, however, not address directly any aspects concerned with the pairing mechanism. A merit of the criterion is that it can be easily applied to the stability analysis of superconducting states in multi-band systems, to establish gap structures favourable within a given complex band structure. As such it can serve as a tool to identify non-trivial mechanisms to suppress superconductivity under various external influences, in particular, magnetic fields or distortions. We apply our criterion to the multi-band superconductor Sr2RuO4 with the aim to explore possible explanations for the limiting feature observed in the in-plane upper critical field. This work was supported by Dr. Max Rössler, the Walter Haefner Foundation and the ETH Zurich Foundation (AR) and by the Swiss National Science Foundation (MS).

  15. Shape resonances and shell effects in thin-film multiband superconductors

    NASA Astrophysics Data System (ADS)

    Romero-Bermúdez, Aurelio; García-García, Antonio M.

    2014-01-01

    We study analytically the evolution of superconductivity in clean quasi-two-dimensional multiband superconductors as the film thickness enters the nanoscale region by mean-field and semiclassical techniques. Tunneling into the substrate and finite lateral size effects, which are important in experiments, are also considered in our model. As a result, it is possible to investigate the interplay between quantum coherence effects, such as shape resonances and shell effects, with the potential to enhance superconductivity, and the multiband structure and the coupling to the substrate that tend to suppress it. The case of magnesium diboride, which is the conventional superconductor with the highest critical temperature, is discussed in detail. Once the effect of the substrate is considered, we still observe quantum size effects such as the oscillation of the critical temperature with the thickness but without a significant enhancement of superconductivity. In thin films with a sufficiently longer superconducting coherence length, it is, however, possible to increase the critical temperature above the bulk limit by tuning the film thickness or lateral size.

  16. Optical frequency comb based multi-band microwave frequency conversion for satellite applications.

    PubMed

    Yang, Xinwu; Xu, Kun; Yin, Jie; Dai, Yitang; Yin, Feifei; Li, Jianqiang; Lu, Hua; Liu, Tao; Ji, Yuefeng

    2014-01-13

    Based on optical frequency combs (OFC), we propose an efficient and flexible multi-band frequency conversion scheme for satellite repeater applications. The underlying principle is to mix dual coherent OFCs with one of which carrying the input signal. By optically channelizing the mixed OFCs, the converted signal in different bands can be obtained in different channels. Alternatively, the scheme can be configured to generate multi-band local oscillators (LO) for widely distribution. Moreover, the scheme realizes simultaneous inter- and intra-band frequency conversion just in a single structure and needs only three frequency-fixed microwave sources. We carry out a proof of concept experiment in which multiple LOs with 2 GHz, 10 GHz, 18 GHz, and 26 GHz are generated. A C-band signal of 6.1 GHz input to the proposed scheme is successfully converted to 4.1 GHz (C band), 3.9 GHz (C band) and 11.9 GHz (X band), etc. Compared with the back-to-back (B2B) case measured at 0 dBm input power, the proposed scheme shows a 9.3% error vector magnitude (EVM) degradation at each output channel. Furthermore, all channels satisfy the EVM limit in a very wide input power range. PMID:24515046

  17. RRI-GBT MULTI-BAND RECEIVER: MOTIVATION, DESIGN, AND DEVELOPMENT

    SciTech Connect

    Maan, Yogesh; Deshpande, Avinash A.; Chandrashekar, Vinutha; Chennamangalam, Jayanth; Rao, K. B. Raghavendra; Somashekar, R.; Ezhilarasi, M. S.; Sujatha, S.; Kasturi, S.; Sandhya, P.; Duraichelvan, R.; Amiri, Shahram; Aswathappa, H. A.; Sarabagopalan, G.; Ananda, H. M.; Anderson, Gary; Bauserman, Jonah; Beaudet, Carla; Bloss, Marty; Barve, Indrajit V.; and others

    2013-01-15

    We report the design and development of a self-contained multi-band receiver (MBR) system, intended for use with a single large aperture to facilitate sensitive and high time-resolution observations simultaneously in 10 discrete frequency bands sampling a wide spectral span (100-1500 MHz) in a nearly log-periodic fashion. The development of this system was primarily motivated by need for tomographic studies of pulsar polar emission regions. Although the system design is optimized for the primary goal, it is also suited for several other interesting astronomical investigations. The system consists of a dual-polarization multi-band feed (with discrete responses corresponding to the 10 bands pre-selected as relatively radio frequency interference free), a common wide-band radio frequency front-end, and independent back-end receiver chains for the 10 individual sub-bands. The raw voltage time sequences corresponding to 16 MHz bandwidth each for the two linear polarization channels and the 10 bands are recorded at the Nyquist rate simultaneously. We present the preliminary results from the tests and pulsar observations carried out with the Robert C. Byrd Green Bank Telescope using this receiver. The system performance implied by these results and possible improvements are also briefly discussed.

  18. Interaction and multiband effects in the intrinsic spin-Hall effect of an interacting multiorbital metal

    NASA Astrophysics Data System (ADS)

    Arakawa, Naoya

    The spin-Hall effect is a spin-current version of the usual-Hall effect, and its potential for application may be great. For the efficient application utilizing the spin-Hall effect, an understanding of interaction effects may be helpful because the interaction effects sometimes become remarkable in transport phenomena (e.g., fractional-quantum-Hall effect). However, a lot of theoretical studies neglected the interaction effects, and the interaction effects in the spin-Hall effect had been little understood. To improve this situation, I developed a general formalism for the intrinsic spin-Hall effect including the interaction effects and multiband effects by using the linear-response theory with approximations appropriate for an interacting multiorbital metal (see arXiv:1510.03988). In this talk, I explain how the electron-electron interaction modifies the spin-Hall conductivity and show several new and remarkable interactions effects, new mechanisms of the damping dependence and a crossover of the damping dependence in a clean system and a temperature-dependent correction due to the spin-Coulomb drag. I also show guidelines useful for general formulations of other transport phenomena including the interaction effects and multiband effects.

  19. CONSTRAINING GAMMA-RAY BURST EMISSION PHYSICS WITH EXTENSIVE EARLY-TIME, MULTIBAND FOLLOW-UP

    SciTech Connect

    Cucchiara, A.; Cenko, S. B.; Bloom, J. S.; Morgan, A.; Perley, D. A.; Li, W.; Butler, N. R.; Filippenko, A. V.; Melandri, A.; Kobayashi, S.; Smith, R. J.; Mundell, C. G.; Steele, I. A.; Hora, J. L.; Da Silva, R. L.; Prochaska, J. X.; Worseck, G.; Fumagalli, M.; Cobb, B.; and others

    2011-12-20

    Understanding the origin and diversity of emission processes responsible for gamma-ray bursts (GRBs) remains a pressing challenge. While prompt and contemporaneous panchromatic observations have the potential to test predictions of the internal-external shock model, extensive multiband imaging has been conducted for only a few GRBs. We present rich, early-time, multiband data sets for two Swift events, GRB 110205A and GRB 110213A. The former shows optical emission since the early stages of the prompt phase, followed by the steep rising in flux up to {approx}1000 s after the burst (t{sup -{alpha}} with {alpha} = -6.13 {+-} 0.75). We discuss this feature in the context of the reverse-shock scenario and interpret the following single power-law decay as being forward-shock dominated. Polarization measurements, obtained with the RINGO2 instrument mounted on the Liverpool Telescope, also provide hints on the nature of the emitting ejecta. The latter event, instead, displays a very peculiar optical to near-infrared light curve, with two achromatic peaks. In this case, while the first peak is probably due to the onset of the afterglow, we interpret the second peak to be produced by newly injected material, signifying a late-time activity of the central engine.

  20. Generation of multiband chorus by lower band cascade in the Earth's magnetosphere

    NASA Astrophysics Data System (ADS)

    Gao, Xinliang; Lu, Quanming; Bortnik, Jacob; Li, Wen; Chen, Lunjin; Wang, Shui

    2016-03-01

    Chorus waves are intense electromagnetic whistler mode emissions in the magnetosphere, typically falling into two distinct frequency bands: a lower band (0.1-0.5fce) and an upper band (0.5-0.8fce) with a power gap at about 0.5fce. In this letter, with the Time History of Events and Macroscale Interactions during Substorms satellite, we observed two special chorus events, which are called as multiband chorus because upper band chorus is located at harmonics of lower band chorus. We propose a new potential generation mechanism for multiband chorus, which is called as lower band cascade. In this scenario, a density mode with a frequency equal to that of lower band chorus is generated by the ponderomotive effect (inhomogeneity of the electric amplitude) along the wave vector, and then upper band chorus with the frequency twice that of lower band chorus is generated through wave-wave couplings between lower band chorus and the density mode. The mechanism provides a new insight into the evolution of whistler mode chorus in the Earth's magnetosphere.

  1. Multi-Band Received Signal Strength Fingerprinting Based Indoor Location System

    NASA Astrophysics Data System (ADS)

    Sertthin, Chinnapat; Fujii, Takeo; Ohtsuki, Tomoaki; Nakagawa, Masao

    This paper proposes a new multi-band received signal strength (MRSS) fingerprinting based indoor location system, which employs the frequency diversity on the conventional single-band received signal strength (RSS) fingerprinting based indoor location system. In the proposed system, the impacts of frequency diversity on the enhancements of positioning accuracy are analyzed. Effectiveness of the proposed system is proved by experimental approach, which was conducted in non line-of-sight (NLOS) environment under the area of 103m2 at Yagami Campus, Keio University. WLAN access points, which simultaneously transmit dual-band signal of 2.4 and 5.2GHz, are utilized as transmitters. Likewise, a dual-band WLAN receiver is utilized as a receiver. Signal distances calculated by both Manhattan and Euclidean were classified by K-Nearest Neighbor (KNN) classifier to illustrate the performance of the proposed system. The results confirmed that Frequency diversity attributions of multi-band signal provide accuracy improvement over 50% of the conventional single-band.

  2. Atomically flat superconducting nanofilms: multiband properties and mean-field theory

    NASA Astrophysics Data System (ADS)

    Shanenko, A. A.; Aguiar, J. Albino; Vagov, A.; Croitoru, M. D.; Milošević, M. V.

    2015-05-01

    Recent progress in materials synthesis enabled fabrication of superconducting atomically flat single-crystalline metallic nanofilms with thicknesses down to a few monolayers. Interest in such nano-thin systems is attracted by the dimensional 3D-2D crossover in their coherent properties which occurs with decreasing the film thickness. The first fundamental aspect of this crossover is dictated by the Mermin-Wagner-Hohenberg theorem and concerns frustration of the long-range order due to superconductive fluctuations and the possibility to track its impact with an unprecedented level of control. The second important aspect is related to the Fabri-Pérot modes of the electronic motion strongly bound in the direction perpendicular to the nanofilm. The formation of such modes results in a pronounced multiband structure that changes with the nanofilm thickness and affects both the mean-field behavior and superconductive fluctuations. Though the subject is very rich in physics, it is scarcely investigated to date. The main obstacle is that there are no manageable models to study a complex magnetic response in this case. Full microscopic consideration is rather time consuming, if practicable at all, while the standard Ginzburg-Landau theory is not applicable. In the present work we review the main achievements in the subject to date, and construct and justify an efficient multiband mean-field formalism which allows for numerical and even analytical treatment of nano-thin superconductors in applied magnetic fields.

  3. Constraining Kepler Eclipsing Binary Properties with Time-Series and Multi-band Photometry

    NASA Astrophysics Data System (ADS)

    Windemuth, Diana; Agol, Eric

    2015-01-01

    We perform simultaneous fits to time-series (Kepler) and multi-band (SDSS griz + 2MASS JHKs) photometry to constrain stellar and orbital parameters of eclipsing binaries (EBs) from the Kepler Eclipsing Binary Catalogue. We infer the stellar parameters by comparing Padova stellar evolution models to the extinction-corrected multi-band photometric data, and use the results as inputs to a Keplerian orbit model for the lightcurves. This method yields a self-consistent analysis and jointly constrains properties of both stars (orbital elements e, ω, i, tpe, p + stellar parameters rA, rB, mA, mB, fB/fA, [Fe/H], age, and quadratic limb darkening coefficients uA1, uA2, uB1, uB2). We apply our coupled time-series photometry and SED model to a sub-sample of detached EBs with p = 10 - 40 d, to minimize the influence of tidal or Doppler effects. The results of this analysis will feed into our circumbinary planet search, wherein we apply barycentric corrections to the Kepler EB lightcurves to look for signals due to planetary companions.

  4. Thermal and Nonthermal Signatures of the Unruh Effect in Casimir-Polder Forces

    NASA Astrophysics Data System (ADS)

    Marino, Jamir; Noto, Antonio; Passante, Roberto

    2014-07-01

    We show that Casimir-Polder forces between two relativistic uniformly accelerated atoms exhibit a transition from the short distance thermal-like behavior predicted by the Unruh effect to a long distance nonthermal behavior, associated with the breakdown of a local inertial description of the system. This phenomenology extends the Unruh thermal response detected by a single accelerated observer to an accelerated spatially extended system of two particles, and we identify the characteristic length scale for this crossover with the inverse of the proper acceleration of the two atoms. Our results are derived separating at fourth order in perturbation theory the contributions of vacuum fluctuations and radiation reaction field to the Casimir-Polder interaction between two atoms moving in two generic stationary trajectories separated by a constant distance and linearly coupled to a scalar field. The field can be assumed in its vacuum state or at finite temperature, resulting in a general method for the computation of Casimir-Polder forces in stationary regimes.

  5. Non-thermal Nanoelectroablation of UV-induced Murine Melanomas Stimulates an Immune Response

    PubMed Central

    Nuccitelli, Richard; Tran, Kevin; Lui, Kaying; Huynh, Joanne; Athos, Brian; Kreis, Mark; Nuccitelli, Pamela; De Fabo, Edward C.

    2013-01-01

    Summary Non-thermal nanoelectroablation therapy completely ablates UV-induced murine melanomas. C57/BL6-HGF/SF transgenic mice were exposed to UV radiation as pups and began to develop visible melanomas 5–6 months later. We have treated 27 of these melanomas in 14 mice with nanosecond pulsed electric field (nsPEF) therapy delivering 2000 electric pulses each 100 ns long and 30 kV/cm at a rate of 5–7 pulses per second. All nanoelectroablated melanoma tumors began to shrink within a day after treatment and gradually disappeared over a period of 12–29 days. Pyknosis of nuclei was evident within 1 h of nsPEF treatment, and DNA fragmentation as detected by TUNEL staining was evident by 6 h after nsPEF treatment. In a melanoma allograft system, nsPEF treatment was superior to tumor excision at accelerating secondary tumor rejection in immune-competent mice, suggesting enhanced stimulation of a protective immune response by nsPEF-treated melanomas. This is supported by the presence of CD4+-T cells within treated tumors as well as within untreated tumors located in mice with other melanomas that had been treated with nanoelectroablation at least 19 days earlier. PMID:22686288

  6. EVIDENCE OF NON-THERMAL X-RAY EMISSION FROM HH 80

    SciTech Connect

    López-Santiago, J.; Peri, C. S.; Benaglia, P.; Bonito, R.; Miceli, M.; Albacete-Colombo, J. F.; De Castro, E.

    2013-10-20

    Protostellar jets appear at all stages of star formation when the accretion process is still at work. Jets travel at velocities of hundreds of km s{sup –1}, creating strong shocks when interacting with the interstellar medium. Several cases of jets have been detected in X-rays, typically showing soft emission. For the first time, we report evidence of hard X-ray emission possibly related to non-thermal processes not explained by previous models of the post-shock emission predicted in the jet/ambient interaction scenario. HH 80 is located at the south head of the jet associated with the massive protostar IRAS 18162-2048. It shows soft and hard X-ray emission in regions that are spatially separated, with the soft X-ray emission region situated behind the region of hard X-ray emission. We propose a scenario for HH 80 where soft X-ray emission is associated with thermal processes from the interaction of the jet with denser ambient matter and hard X-ray emission is produced by synchrotron radiation at the front shock.

  7. The impact of non-thermal electrons on resolved black hole accretion disk images

    NASA Astrophysics Data System (ADS)

    Mao, Shengkai; Dexter, Jason; Quataert, Eliot

    2015-01-01

    Recent developments in radio astronomy (in particular, the Event Horizon Telescope) allow us for the first time to resolve length scales around the Milky Way's Sgr A* comparable to the event horizon radius. These observations are opening up new opportunities to study strong gravity and accretion physics in the vicinity of a supermassive black hole. However, the processes governing black hole accretion are not well understood. In particular, the electron thermodynamics in black hole accretion disks remain mysterious, and current models vary significantly from each other. The impact of these differences between current electron thermodynamics models on results obtained from EHT images is not well understood. Thus, in this work, we explore the effects of non-thermal electrons on black hole images and radio spectra in the context of both semi-analytic and numerical models of accretion flows. Using general relativistic ray-tracing and radiative transfer code, we simulate images of the accretion disk around Sgr A* and compare our simulations to observed radio data. We estimate the range of electron energy distribution functions permissible by the data. In so doing, we also explore the range and variety of black hole images obtained by varying the distribution function.

  8. Acceleration of relativistic electrons by magnetohydrodynamic turbulence: Implications for non-thermal emission from black hole accretion disks

    SciTech Connect

    Lynn, Jacob W.; Quataert, Eliot; Chandran, Benjamin D. G.; Parrish, Ian J.

    2014-08-10

    We use analytic estimates and numerical simulations of test particles interacting with magnetohydrodynamic (MHD) turbulence to show that subsonic MHD turbulence produces efficient second-order Fermi acceleration of relativistic particles. This acceleration is not well described by standard quasi-linear theory but is a consequence of resonance broadening of wave-particle interactions in MHD turbulence. We provide momentum diffusion coefficients that can be used for astrophysical and heliospheric applications and discuss the implications of our results for accretion flows onto black holes. In particular, we show that particle acceleration by subsonic turbulence in radiatively inefficient accretion flows can produce a non-thermal tail in the electron distribution function that is likely important for modeling and interpreting the emission from low-luminosity systems such as Sgr A* and M87.

  9. A comprehensive study of channel estimation for WBAN-based healthcare systems: feasibility of using multiband UWB.

    PubMed

    Islam, S M Riazul; Kwak, Kyung Sup

    2012-06-01

    Wireless personal area network (WPAN) is an emerging in wireless technology for short range indoor and outdoor communication applications. A more specific category of WPAN is the wireless body area network (WBAN) used for health monitoring. On the other hand, multiband orthogonal frequency division multiplexing (MB-OFDM) ultra-wideband (UWB) comes with a number of desirable features at the physical layer for wireless communications, for example, very high data rate. One big challenge in adoption of multiband UWB in WBAN is the fact that channel estimation becomes difficult under the constraint of extremely low transmission power. Moreover, the heterogeneous environment of WBAN causes a dense multipath wireless channel. Therefore, effective channel estimation is required in the receiver of WBAN-based healthcare system that uses multiband UWB. In this paper, we first outline the MB-OFDM UWB system. Then, we present an overview of channel estimation techniques proposed/investigated for multiband UWB communications with emphasis on their strengths and weaknesses. Useful suggestions are given to overcome the weaknesses so that these methods can be particularly useful for WBAN channels. Also, we analyze the comparative performances of the techniques using computer simulation in order to find the energy-efficient channel estimation methods for WBAN-based healthcare systems. PMID:21046206

  10. Tracking the energetics of the non-thermal disc-corona-jet in the very high state GX 339 - 4

    NASA Astrophysics Data System (ADS)

    Kubota, A.; Done, C.

    2016-06-01

    The dramatic hard-soft spectral transition in black hole binaries is important as it is associated with the collapse of the jet and with the strongest low-frequency quasi-periodic oscillations (QPOs). These transition spectra (intermediate and very high state: VHS) are complex, with soft but distinctly non-thermal Comptonization which merges smoothly into the disc emission. Here we develop a physical model for the accretion flow which can accommodate all these features, with an outer standard disc, which can make a transition to an energetically coupled disc-corona region, and make a further transition to a hot inner flow which can be radiatively inefficient if required. The code explicitly uses fully relativistic emissivity (Novikov-Thorne), and all Comptonization is calculated with a hybrid (thermal and non-thermal) electron distribution. We fit this to a VHS spectrum from GX 339 - 4. We show that the complex continuum curvature produced by a hybrid electron distribution is enough to remove the strong constraint on black hole spin derived from reflection using simpler Comptonization models. More fundamentally, we show that the VHS cannot be fit with the same Novikov-Thorne emissivity which can fit the disc-dominated spectrum but instead requires that the inner flow is somewhat radiatively inefficient. This is consistent with an accretion powered jet, but simultaneous radio data show that the jet has already collapsed at the time of our data. Instead, it could point to truncation of the inner flow at radii larger than the innermost stable circular orbit, as predicted by the Lense-Thirring QPO models.

  11. Cancer therapy using non-thermal atmospheric pressure plasma with ultra-high electron density

    SciTech Connect

    Tanaka, Hiromasa; Mizuno, Masaaki; Toyokuni, Shinya; Maruyama, Shoichi; Kodera, Yasuhiro; Terasaki, Hiroko; Adachi, Tetsuo; Kato, Masashi; Kikkawa, Fumitaka; Hori, Masaru

    2015-12-15

    Cancer therapy using non-thermal atmospheric pressure plasma is a big challenge in plasma medicine. Reactive species generated from plasma are key factors for treating cancer cells, and thus, non-thermal atmospheric pressure plasma with high electron density has been developed and applied for cancer treatment. Various cancer cell lines have been treated with plasma, and non-thermal atmospheric plasma clearly has anti-tumor effects. Recent innovative studies suggest that plasma can both directly and indirectly affect cells and tissues, and this observation has widened the range of applications. Thus, cancer therapy using non-thermal atmospheric pressure plasma is promising. Animal experiments and understanding the mode of action are essential for clinical application in the future. A new academic field that combines plasma science, the biology of free radicals, and systems biology will be established.

  12. Cancer therapy using non-thermal atmospheric pressure plasma with ultra-high electron density

    NASA Astrophysics Data System (ADS)

    Tanaka, Hiromasa; Mizuno, Masaaki; Toyokuni, Shinya; Maruyama, Shoichi; Kodera, Yasuhiro; Terasaki, Hiroko; Adachi, Tetsuo; Kato, Masashi; Kikkawa, Fumitaka; Hori, Masaru

    2015-12-01

    Cancer therapy using non-thermal atmospheric pressure plasma is a big challenge in plasma medicine. Reactive species generated from plasma are key factors for treating cancer cells, and thus, non-thermal atmospheric pressure plasma with high electron density has been developed and applied for cancer treatment. Various cancer cell lines have been treated with plasma, and non-thermal atmospheric plasma clearly has anti-tumor effects. Recent innovative studies suggest that plasma can both directly and indirectly affect cells and tissues, and this observation has widened the range of applications. Thus, cancer therapy using non-thermal atmospheric pressure plasma is promising. Animal experiments and understanding the mode of action are essential for clinical application in the future. A new academic field that combines plasma science, the biology of free radicals, and systems biology will be established.

  13. Cell death induced by ozone and various non-thermal plasmas: therapeutic perspectives and limitations

    PubMed Central

    Lunov, Oleg; Zablotskii, Vitalii; Churpita, Olexander; Chánová, Eliška; Syková, Eva; Dejneka, Alexandr; Kubinová, Šárka

    2014-01-01

    Non-thermal plasma has been recognized as a promising tool across a vast variety of biomedical applications, with the potential to create novel therapeutic methods. However, the understanding of the molecular mechanisms behind non-thermal plasma cellular effects remains a significant challenge. In this study, we show how two types of different non-thermal plasmas induce cell death in mammalian cell cultures via the formation of multiple intracellular reactive oxygen/nitrogen species. Our results showed a discrepancy in the superoxide accumulation and lysosomal activity in response to air and helium plasma, suggesting that triggered signalling cascades might be grossly different between different plasmas. In addition, the effects of ozone, a considerable component of non-thermal plasma, have been simultaneously evaluated and have revealed much faster and higher cytotoxic effects. Our findings offer novel insight into plasma-induced cellular responses, and provide a basis for better controlled biomedical applications. PMID:25410636

  14. Observation of Nonthermal Emission from the Supernova Remnant IC443 with RXTE

    NASA Technical Reports Server (NTRS)

    Sturner, S. J.; Keohane, J. W.; Reimer, O.

    2002-01-01

    In this paper we present analysis of X-ray spectra from the supernova remnant IC443 obtained using the PCA on RXTE. The spectra in the 3 - 20 keV band are well fit by a two-component model consisting of thermal and nonthermal components. We compare these results with recent results of other X-ray missions and discuss the need for a cut-off in the nonthermal spectrum. Recent Chandra and XMM-Newton observations suggest that much of the nonthermal emission from IC443 can be attributed to a pulsar wind nebula. We present the results of our search for periodic emission in the RXTE PCA data. We then discuss the origin o f the nonthermal component and its possible association with the unidentified EGRET source.

  15. Low dust charging rate induced weakly dissipative dust acoustic solitary waves: Role of nonthermal ions

    SciTech Connect

    Chaudhuri, Tushar Kanti; Khan, Manoranjan; Gupta, M. R.; Ghosh, Samiran

    2007-10-15

    The effects of low dust charging rate compared to the dust oscillation frequency and nonthermal ions on small but finite amplitude nonlinear dust acoustic wave have been investigated. It is seen that because of the low dust charging rate, the nonlinear wave exhibits weakly dissipative solitary wave that is governed by a modified form of the Korteweg-de Vries equation. The solitary wave possesses both rarefactive and compressive soliton solution depending on the values of ion nonthermality parameter a. An analytical solution reveals that because of the simultaneous effects of low dust charging rate and nonthermal ions, the wave amplitude may grow exponentially with time if the ion nonthermality parameter (a) exceeds a critical value provided the ion-electron temperature ratio ({sigma}{sub i}) is less than 0.11.

  16. Cell death induced by ozone and various non-thermal plasmas: therapeutic perspectives and limitations

    NASA Astrophysics Data System (ADS)

    Lunov, Oleg; Zablotskii, Vitalii; Churpita, Olexander; Chánová, Eliška; Syková, Eva; Dejneka, Alexandr; Kubinová, Šárka

    2014-11-01

    Non-thermal plasma has been recognized as a promising tool across a vast variety of biomedical applications, with the potential to create novel therapeutic methods. However, the understanding of the molecular mechanisms behind non-thermal plasma cellular effects remains a significant challenge. In this study, we show how two types of different non-thermal plasmas induce cell death in mammalian cell cultures via the formation of multiple intracellular reactive oxygen/nitrogen species. Our results showed a discrepancy in the superoxide accumulation and lysosomal activity in response to air and helium plasma, suggesting that triggered signalling cascades might be grossly different between different plasmas. In addition, the effects of ozone, a considerable component of non-thermal plasma, have been simultaneously evaluated and have revealed much faster and higher cytotoxic effects. Our findings offer novel insight into plasma-induced cellular responses, and provide a basis for better controlled biomedical applications.

  17. Planck-scale nonthermal correlations in a noncommutative geometry inspired Vaidya black hole

    NASA Astrophysics Data System (ADS)

    Mehdipour, S. Hamid

    2012-05-01

    Using the noncommutative geometry inspired Vaidya metric obtained in terms of coordinate coherent states and also utilizing the generalized uncertainty principle (GUP), we show that the nonthermal nature of the Hawking spectrum leads to Planck-scale nonthermal correlations between emitted modes of evaporation. Our analysis thus exhibits that owing to self-gravitational effects plus noncommutativity and GUP influences, information can emerge in the form of Planck-scale correlated emissions from the black hole.

  18. Nonlinear localized dust acoustic waves in a charge varying dusty plasma with nonthermal ions

    SciTech Connect

    Tribeche, Mouloud; Amour, Rabia

    2007-10-15

    A numerical investigation is presented to show the existence, formation, and possible realization of large-amplitude dust acoustic (DA) solitary waves in a charge varying dusty plasma with nonthermal ions. These nonlinear localized structures are self-consistent solutions of the collisionless Vlasov equation with a population of fast particles. The spatial patterns of the variable charge DA solitary wave are significantly modified by the nonthermal effects. The results complement and provide new insights into previously published results on this problem.

  19. Dust-ion-acoustic solitary structure with opposite polarity ions and non-thermal electrons

    NASA Astrophysics Data System (ADS)

    Haider, M. M.

    2016-02-01

    The propagation of dust-ion-acoustic solitary waves in magnetized plasmas containing opposite polarity ions, opposite polarity dusts and non-thermal electrons has been studied. The fluid equations in the system are reduced to a Korteweg-de Vries equation in the limit of small amplitude perturbation. The effect of non-thermal electrons and the opposite polarity of ions and dusts in the solitary waves are presented graphically and numerically.

  20. Integrated continuum-atomistic modeling of nonthermal ablation of gold nanofilms by femtosecond lasers

    NASA Astrophysics Data System (ADS)

    Gan, Yong; Chen, J. K.

    2009-05-01

    Ultrafast nonthermal ablation of gold nanofilms is studied using a combined two-temperature model and molecular dynamics method. The results show that for thinner films the tensile stress is directly reversed from the initially generated compressive stress. For thicker films, on the other hand, the tensile stress wave is reflected from the irradiated surface. The key driving force for ultrafast nonthermal material ablation is conventional thermal stress, instead of the hot electron blast force.

  1. Simulating three-dimensional nonthermal high-energy photon emission in colliding-wind binaries

    SciTech Connect

    Reitberger, K.; Kissmann, R.; Reimer, A.; Reimer, O.

    2014-07-01

    Massive stars in binary systems have long been regarded as potential sources of high-energy γ rays. The emission is principally thought to arise in the region where the stellar winds collide and accelerate relativistic particles which subsequently emit γ rays. On the basis of a three-dimensional distribution function of high-energy particles in the wind collision region—as obtained by a numerical hydrodynamics and particle transport model—we present the computation of the three-dimensional nonthermal photon emission for a given line of sight. Anisotropic inverse Compton emission is modeled using the target radiation field of both stars. Photons from relativistic bremsstrahlung and neutral pion decay are computed on the basis of local wind plasma densities. We also consider photon-photon opacity effects due to the dense radiation fields of the stars. Results are shown for different stellar separations of a given binary system comprising of a B star and a Wolf-Rayet star. The influence of orbital orientation with respect to the line of sight is also studied by using different orbital viewing angles. For the chosen electron-proton injection ratio of 10{sup –2}, we present the ensuing photon emission in terms of two-dimensional projections maps, spectral energy distributions, and integrated photon flux values in various energy bands. Here, we find a transition from hadron-dominated to lepton-dominated high-energy emission with increasing stellar separations. In addition, we confirm findings from previous analytic modeling that the spectral energy distribution varies significantly with orbital orientation.

  2. Analytical model for non-thermal pressure in galaxy clusters - II. Comparison with cosmological hydrodynamics simulation

    NASA Astrophysics Data System (ADS)

    Shi, Xun; Komatsu, Eiichiro; Nelson, Kaylea; Nagai, Daisuke

    2015-03-01

    Turbulent gas motion inside galaxy clusters provides a non-negligible non-thermal pressure support to the intracluster gas. If not corrected, it leads to a systematic bias in the estimation of cluster masses from X-ray and Sunyaev-Zel'dovich (SZ) observations assuming hydrostatic equilibrium, and affects interpretation of measurements of the SZ power spectrum and observations of cluster outskirts from ongoing and upcoming large cluster surveys. Recently, Shi & Komatsu developed an analytical model for predicting the radius, mass, and redshift dependence of the non-thermal pressure contributed by the kinetic random motions of intracluster gas sourced by the cluster mass growth. In this paper, we compare the predictions of this analytical model to a state-of-the-art cosmological hydrodynamics simulation. As different mass growth histories result in different non-thermal pressure, we perform the comparison on 65 simulated galaxy clusters on a cluster-by-cluster basis. We find an excellent agreement between the modelled and simulated non-thermal pressure profiles. Our results open up the possibility of using the analytical model to correct the systematic bias in the mass estimation of galaxy clusters. We also discuss tests of the physical picture underlying the evolution of intracluster non-thermal gas motions, as well as a way to further improve the analytical modelling, which may help achieve a unified understanding of non-thermal phenomena in galaxy clusters.

  3. Hydrodynamic simulation of non-thermal pressure profiles of galaxy clusters

    SciTech Connect

    Nelson, Kaylea; Nagai, Daisuke; Lau, Erwin T.

    2014-09-01

    Cosmological constraints from X-ray and microwave observations of galaxy clusters are subjected to systematic uncertainties. Non-thermal pressure support due to internal gas motions in galaxy clusters is one of the major sources of astrophysical uncertainties. Using a mass-limited sample of galaxy clusters from a high-resolution hydrodynamical cosmological simulation, we characterize the non-thermal pressure fraction profile and study its dependence on redshift, mass, and mass accretion rate. We find that the non-thermal pressure fraction profile is universal across redshift when galaxy cluster radii are defined with respect to the mean matter density of the universe instead of the commonly used critical density. We also find that the non-thermal pressure is predominantly radial, and the gas velocity anisotropy profile exhibits strong universality when galaxy cluster radii are defined with respect to the mean matter density of the universe. However, we find that the non-thermal pressure fraction is strongly dependent on the mass accretion rate of the galaxy cluster. We provide fitting formulae for the universal non-thermal pressure fraction and velocity anisotropy profiles of gas in galaxy clusters, which should be useful in modeling astrophysical uncertainties pertinent to using galaxy clusters as cosmological probes.

  4. Optimization of Non-Thermal Plasma Treatment in an In Vivo Model Organism

    PubMed Central

    Lee, Amanda; Lin, Abraham; Shah, Kajol; Singh, Harpreet; Miller, Vandana; Gururaja Rao, Shubha

    2016-01-01

    Non-thermal plasma is increasingly being recognized for a wide range of medical and biological applications. However, the effect of non-thermal plasma on physiological functions is not well characterized in in vivo model systems. Here we use a genetically amenable, widely used model system, Drosophila melanogaster, to develop an in vivo system, and investigate the role of non-thermal plasma in blood cell differentiation. Although the blood system in Drosophila is primitive, it is an efficient system with three types of hemocytes, functioning during different developmental stages and environmental stimuli. Blood cell differentiation in Drosophila plays an essential role in tissue modeling during embryogenesis, morphogenesis and also in innate immunity. In this study, we optimized distance and frequency for a direct non-thermal plasma application, and standardized doses to treat larvae and adult flies so that there is no effect on the viability, fertility or locomotion of the organism. We discovered that at optimal distance, time and frequency, application of plasma induced blood cell differentiation in the Drosophila larval lymph gland. We articulate that the augmented differentiation could be due to an increase in the levels of reactive oxygen species (ROS) upon non-thermal plasma application. Our studies open avenues to use Drosophila as a model system in plasma medicine to study various genetic disorders and biological processes where non-thermal plasma has a possible therapeutic application. PMID:27505063

  5. Calibrated Landsat ETM+ nonthermal-band image mosaics of Afghanistan

    USGS Publications Warehouse

    Davis, Philip A.

    2006-01-01

    In 2005, the U.S. Agency for International Development and the U.S. Trade and Development Agency contracted with the U.S. Geological Survey to perform assessments of the natural resources within Afghanistan. The assessments concentrate on the resources that are related to the economic development of that country. Therefore, assessments were initiated in oil and gas, coal, mineral resources, water resources, and earthquake hazards. All of these assessments require geologic, structural, and topographic information throughout the country at a finer scale and better accuracy than that provided by the existing maps, which were published in the 1970s by the Russians and Germans. The very rugged terrain in Afghanistan, the large scale of these assessments, and the terrorist threat in Afghanistan indicated that the best approach to provide the preliminary assessments was to use remotely sensed, satellite image data, although this may also apply to subsequent phases of the assessments. Therefore, the first step in the assessment process was to produce satellite image mosaics of Afghanistan that would be useful for these assessments. This report discusses the production and characteristics of the fundamental satellite image databases produced for these assessments, which are calibrated image mosaics of all six Landsat nonthermal (reflected) bands.

  6. Non-thermal discharge processing of gaseous pollutants

    SciTech Connect

    Vogtlin, G.; Penetrante, B.; Wallman, H.

    1993-08-27

    The electrical discharge techniques, called non-thermal, utilize high voltage breakdown of gases using short pulses of one to a few hundred nanoseconds. These short pulses between metal electrodes generate energetic electrons without appreciable thermal heating of the gas. The energetic electrons collide with gas molecules to form radicals. The radicals then react with pollutants to form harmless compounds. Our experimental device uses a wire in a pipe geometry. The wire is driven by a 40 kilovolt pulse 100 nanoseconds long. Gas is circulated in a loop through the pipe geometry in a closed system. This system permits the introduction of various gas combinations prior to testing. The recirculated gas can be heated to determine the effect on the electrical discharge, and chemical reactions. The efficiency of pollutant removal is the key to applications. We have been able to significantly improve the efficiency of NO removal by the addition of hydrocarbons. Nitric oxide has been removed with an energy cost of 15 ev per NO molecule. We believe the hydrocarbon additive serves by recycling the hydroxyl radicals during the oxidation and reduction of NO. The implementation of this process will depend largely on how much additives, electrical power consumption, and final NO{sub x} concentration are acceptable for a particular application.

  7. Nitrogen oxides and methane treatment by non-thermal plasma

    NASA Astrophysics Data System (ADS)

    Alva, E.; Pacheco, M.; Colín, A.; Sánchez, V.; Pacheco, J.; Valdivia, R.; Soria, G.

    2015-03-01

    Non thermal plasma was used to treat nitrogen oxides (NOx) and methane (CH4), since they are important constituents of hydrocarbon combustion emissions processes and, both gases, play a key role in the formation of tropospheric ozone. These gases are involved in environmental problems like acid rain and some diseases such as bronchitis and pneumonia. In the case of methane is widely known its importance in the global climate change, and currently accounts for 30% of global warming. There is a growing concern for methane leaks, associated with a rapid expansion of unconventional oil and gas extraction techniques as well as a large-scale methane release from Arctic because of ice melting and the subsequent methane production of decaying organic matter. Therefore, methane mitigation is a key to avoid dangerous levels of global warming. The research, here reported, deals about the generation of non-thermal plasma with a double dielectric barrier (2DBD) at atmospheric pressure with alternating current (AC) for NOx and CH4 treatment. The degradation efficiencies and their respective power consumption for different reactor configurations (cylindrical and planar) are also reported. Qualitative and quantitative analysis of gases degradation are reported before and after treatment with cold plasma. Experimental and theoretical results are compared obtaining good removal efficiencies, superior to 90% and to 20% respectively for NOx and CH4.

  8. Nonthermal Argon Plasma Generator and Some Potential Applications

    NASA Astrophysics Data System (ADS)

    Bunoiu, M.; Jugunaru, I.; Bica, I.; Balasoiu, M.

    2015-12-01

    A laboratory - made nonthermal plasma generator is presented. It has a diameter of 0.020 m and length of 0.155 m and contains two electrodes. The first electrode is a 2% Th-W alloy, 0.002 m in diameter bar, centred inside the generator's body by means of a four channel teflon piece; the other three channels, 0.003 m in diameter, are used for Ar supply. The second electrode is a nozzle of 0.002 m - 0.008 m diameter and 0.005m length. A ~500 kV/m electric field is generated between the two electrodes by a high frequency source (13.56 MHz ±5%), equipped with a OT-1000 (Tungsram) power triode. For Ar flows ranging from 0.00008 m3/s to 0.00056 m3/s, a plasma jet of length not exceeding 0.015 m and temperature below 315 K is obtained. Anthurium andraeanumis sample , blood matrix, human hair and textile fibers may be introduced in the plasma jet. For time periods of 30 s and 60 s, various effects like, cell detexturization, fast blood coagulation or textile fiber or hair cleaning and smoothing are obtained. These effects are presented and discussed in the paper.

  9. Inactivation of human pathogenic dermatophytes by non-thermal plasma.

    PubMed

    Scholtz, Vladimír; Soušková, Hana; Hubka, Vit; Švarcová, Michaela; Julák, Jaroslav

    2015-12-01

    Non-thermal plasma (NTP) was tested as an in vitro deactivation method on four human pathogenic dermatophytes belonging to all ecological groups including anthropophilic Trichophyton rubrum and Trichophyton interdigitale, zoophilic Arthroderma benhamiae, and geophilic Microsporum gypseum. The identification of all strains was confirmed by sequencing of ITS rDNA region (internal transcribed spacer region of ribosomal DNA). Dermatophyte spores were suspended in water or inoculated on agar plates and exposed to NTP generated by a positive or negative corona discharge, or cometary discharge. After 15 min of exposure to NTP a significant decrease in the number of surviving spores in water suspensions was observed in all species. Complete spore inactivation and thus decontamination was observed in anthropophilic species after 25 min of exposure. Similarly, a significant decrease in the number of surviving spores was observed after 10-15 min of exposure to NTP on the surface of agar plates with full inhibition after 25 min in all tested species except of M. gypseum. Although the sensitivity of dermatophytes to the action of NTP appears to be lower than that of bacteria and yeast, our results suggest that NTP has the potential to be used as an alternative treatment strategy for dermatophytosis and could be useful for surface decontamination in clinical practice. PMID:26427826

  10. Determination of mercury by furnace atomic nonthermal excitation spectrometry

    NASA Astrophysics Data System (ADS)

    Dittrich, K.; Franz, T.; Wennrich, R.

    1994-12-01

    The determination of Hg using different variants of the Furnace Atomic Nonthermal Excitation Spectrometry (FANES) is described. In the direct analysis of micro volumes of solutions, the results could be improved by working with chemical modifiers for the stabilization of Hg during the thermal pretreatment. The best results were obtained using Ir and Pd as modifiers, with absolute detection limits of 4 and 12 pg, respectively. The determination of mercury in sample volumes up to 10 ml could be achieved by coupling a cold vapour generation system and an amalgam attachment to the FANES source. A detection limit of 22 ng/l was obtained with this technique. The best results were obtained by using the cold vapour generation technique and in situ enrichment of Hg onto the modified inner surface of the graphite tube of the FANES source. Using Ir for permanent impregnation of the tube a detection limit of 0.0009 μ;g/l was found. The influence of hydride forming elements on the determination of mercury by the technique of vapour generation and in situ enrichment was studied. A reduction of the concentration of NaBH 4 to 0.002% m/v made it possible to determine traces of mercury in presence of a high excess of hydride forming elements without any depression of the Hg emission intensity. The results were validated using standard reference materials.

  11. Non-thermal plasma for air and water remediation.

    PubMed

    Hashim, Siti Aiasah; Samsudin, Farah Nadia Dayana Binti; Wong, Chiow San; Abu Bakar, Khomsaton; Yap, Seong Ling; Mohd Zin, Mohd Faiz

    2016-09-01

    A modular typed dielectric barrier discharge (DBD) device is designed and tested for air and water remediation. The module is made of a number of DBD tubes that can be arranged in series or parallel. Each of the DBD tubes comprises inner electrode enclosed with dielectric barrier and arranged as such to provide a gap for the passage of gases. Non-thermal plasma generated in the gap effectively creates gaseous chemical reactions. Its efficacy in the remediation of gas stream containing high NOx, similar to diesel emission and wastewater containing latex, are presented. A six tubes DBD module has successfully removed more than 80% of nitric oxide from the gas stream. In another arrangement, oxygen was fed into a two tubes DBD to generate ozone for treatment of wastewater. Samples of wastewater were collected from a treatment pond of a rubber vulcanization pilot plant. The water pollution load was evaluated by the chemical oxygen demand (COD) and biological oxygen demand (BOD5) values. Preliminary results showed some improvement (about 13%) on the COD after treatment and at the same time had increased the BOD5 by 42%. This results in higher BOD5/COD ratio after ozonation which indicate better biodegradability of the wastewater. PMID:27056469

  12. Multiband Te p Based Superconductivity of Ta4Pd3Te16

    DOE PAGESBeta

    Singh, David J.

    2014-10-06

    We recently discovered that Ta4Pd3Te16 is a superconductor that has been suggested to be an unconventional superconductor near magnetism. Here, we report electronic structure calculations showing that despite the layered crystal structure the material is an anisotropic three-dimensional (3D) metal. The Fermi surface contains prominent one-dimensional (1D) and two-dimensional (2D) features, including nested 1D sheets, a 2D cylindrical section, and a 3D sheet. Moreover, the electronic states that make up the Fermi surface are mostly derived from Te p states with small Ta d and Pd d contributions. This places the compound far from magnetic instabilities. The results are discussedmore » in terms of multiband superconductivity.« less

  13. Multi-bands photoconductive response in AlGaN/GaN multiple quantum wells

    SciTech Connect

    Chen, G.; Rong, X.; Xu, F. J.; Tang, N.; Wang, X. Q. Shen, B.; Fu, K.; Zhang, B. S.; Hashimoto, H.; Yoshikawa, A.; Ge, W. K.

    2014-04-28

    Based on the optical transitions among the quantum-confined electronic states in the conduction band, we have fabricated multi-bands AlGaN/GaN quantum well infrared photodetectors. Crack-free AlGaN/GaN multiple quantum wells (MQWs) with atomically sharp interfaces have been achieved by inserting an AlN interlayer, which releases most of the tensile strain in the MQWs grown on the GaN underlayer. With significant reduction of dark current by using thick AlGaN barriers, photoconductive responses are demonstrated due to intersubband transition in multiple regions with center wavelengths of 1.3, 2.3, and 4 μm, which shows potential applications on near infrared detection.

  14. Comparison of Tunneling in Fe-based Superconductors with Multi-band MgB2

    NASA Astrophysics Data System (ADS)

    Zasadzinski, John; Iavarone, Maria

    MgB2 is an s-wave, phonon coupled, multiband superconductor that exhibits novel tunneling spectra including a subtle dip feature due to quasiparticle transfer between bands. Since this feature mimics the above-gap spectral dip feature observed in Fe-based superconductors, typically attributed to a strong coupling boson, it is worthwhile to consider whether quasiparticle transfer is relevant. We first show that the dip in MgB2 appears in the π-band, DOS (Δ = 2.4 meV) and is due to quasiparticle transfer to the σ-band with Δ = 7.2 meV. Reviewing the spectral dip in Fe-based superconductors, including new data on FeSe crystals, there are inconsistencies with quasiparticle transfer as the origin. The conclusion is that the spectral dip is more likely due to a boson, the resonance spin excitation, as found in cuprate superconductors.

  15. Simplified radio-over-fiber transport systems with a low-cost multiband light source.

    PubMed

    Chang, Ching-Hung; Peng, Peng-Chun; Lu, Hai-Han; Shih, Chine-Liang; Chen, Hwan-Wen

    2010-12-01

    In this Letter, low-cost radio-over-fiber (ROF) transport systems are proposed and experimentally demonstrated. By utilizing a laser diode (LD) and a local oscillator (LO) to generate coherent multiband optical carriers, as well as a self-composed wavelength selector to separate every two carriers for different ROF transport systems, no any other dedicated LD or electrical frequency upconverting circuit/process is needed in the central station (CS). Compared with current ROF systems, the required numbers of LDs, LOs, and mixers in a CS are significantly reduced. Reducing the number of components not only can simplify the network structure but can also reduce the volume and complexity of the relative logistics. To demonstrate the practice of the proposed ROF transport systems, clear eye diagrams and error-free transmission performance are experimentally presented. PMID:21124599

  16. Bose-Hubbard model with random impurities: Multiband and nonlinear hopping effects

    NASA Astrophysics Data System (ADS)

    Stasińska, Julia; Łacki, Mateusz; Dutta, Omjyoti; Zakrzewski, Jakub; Lewenstein, Maciej

    2014-12-01

    We investigate the phase diagrams of theoretical models describing bosonic atoms in a lattice in the presence of randomly localized impurities. By including multiband and nonlinear hopping effects we enrich the standard model containing only the chemical-potential disorder with the site-dependent hopping term. We compare the extension of the MI and the BG phase in both models using a combination of the local mean-field method and a Hartree-Fock-like procedure, as well as the Gutzwiller-ansatz approach. We show analytical argument for the presence of triple points in the phase diagram of the model with chemical-potential disorder. These triple points, however, cease to exist after the addition of the hopping disorder.

  17. Study of multiband disordered systems using the typical medium dynamical cluster approximation

    DOE PAGESBeta

    Zhang, Yi; Terletska, Hanna; Moore, C.; Ekuma, Chinedu; Tam, Ka-Ming; Berlijn, Tom; Ku, Wei; Moreno, Juana; Jarrell, Mark

    2015-11-06

    We generalize the typical medium dynamical cluster approximation to multiband disordered systems. Using our extended formalism, we perform a systematic study of the nonlocal correlation effects induced by disorder on the density of states and the mobility edge of the three-dimensional two-band Anderson model. We include interband and intraband hopping and an intraband disorder potential. Our results are consistent with those obtained by the transfer matrix and the kernel polynomial methods. We also apply the method to KxFe2-ySe2 with Fe vacancies. Despite the strong vacancy disorder and anisotropy, we find the material is not an Anderson insulator. Moreover our resultsmore » demonstrate the application of the typical medium dynamical cluster approximation method to study Anderson localization in real materials.« less

  18. Study of multiband disordered systems using the typical medium dynamical cluster approximation

    SciTech Connect

    Zhang, Yi; Terletska, Hanna; Moore, C.; Ekuma, Chinedu; Tam, Ka-Ming; Berlijn, Tom; Ku, Wei; Moreno, Juana; Jarrell, Mark

    2015-11-06

    We generalize the typical medium dynamical cluster approximation to multiband disordered systems. Using our extended formalism, we perform a systematic study of the nonlocal correlation effects induced by disorder on the density of states and the mobility edge of the three-dimensional two-band Anderson model. We include interband and intraband hopping and an intraband disorder potential. Our results are consistent with those obtained by the transfer matrix and the kernel polynomial methods. We also apply the method to KxFe2-ySe2 with Fe vacancies. Despite the strong vacancy disorder and anisotropy, we find the material is not an Anderson insulator. Moreover our results demonstrate the application of the typical medium dynamical cluster approximation method to study Anderson localization in real materials.

  19. Spectral and energy parameters of multiband barrier-discharge KrBr excilamps

    SciTech Connect

    Avdeev, S M; Erofeev, M V; Skakun, V S; Sosnin, E A; Suslov, A I; Tarasenko, V F; Schitz, D V

    2008-07-31

    The spectral and energy characteristics of multiband barrier-discharge coaxial KrBr excilamps are studied experimentally at pressures from a few tens of Torr to 0.4 atm. It is shown that an increase in the Br{sub 2} concentration reduces the emission intensity of KrBr* molecules with respect to the emission intensity of Br{sub 2}* molecules and reduces the total emission power of the excilamp. This can be explained by the nonradiative decay of exciplex KrBr* molecules caused by their quenching by molecular bromine. The emission power and efficiency in the Kr:Br{sub 2} = 400:1 mixture at a pressure of {approx}230 Torr and a discharge gap of 8.5 mm were 4.8 W and 2.4%, respectively. (laser applications and other topics in quantum electronics)

  20. Geometric simulation analysis of multi-band mosaic imaging from the same orbit by agile satellites

    NASA Astrophysics Data System (ADS)

    Xu, Yue; Chen, Jinwei; Chen, Yueting; Xu, Zhihai; Feng, Huajun; Li, Qi

    2015-08-01

    This paper establishes a geometric model of multi-band mosaic imaging from the same orbit by agile satellites, and introduces a self-write simulation software. Geometric parameters of each band are calculated based on the attitude control ability of the satellite and the mission requirements. Considering the different ground resolution and the imaging angle of each band, two new concepts, Gradient Entropy and Structure Similarity Parameter are presented. These two values are used to evaluate the change of image quality caused by agility, and help to estimate the effect of the mission. By building the geometric model and calculating the agile information with the program, we propose a new approach of forward analysis of agile imaging, which helps users evaluate the image degradation.

  1. Improving accuracy using subpixel smoothing for multiband effective-mass Hamiltonians of semiconductor nanostructures

    NASA Astrophysics Data System (ADS)

    Hsieh, Chi-Ti; Hsieh, Tung-Han; Chang, Shu-Wei

    2016-04-01

    We develop schemes of subpixel smoothing for the multiband Luttinger-Kohn and Burt-Foreman Hamiltonians of semiconductor nanostructures. With proper procedures of parameter averages at abrupt interfaces, computational errors of envelope functions due to the discontinuity of heterostructures are significantly reduced. Two smoothing approaches are presented. One is based on eliminations of the first-order perturbation in energy, and the other is an application of the Hellmann-Feynman theorem. Using the finite-difference method, we find that while the procedure of perturbation theory seems to be more robust than that of Hellmann-Feynman theorem, the errors of both schemes are (considerably) lower than that without smoothing or with direct but unjustified averages of untransformed parameters. The proposed approaches may enhance numerical accuracies and reduce computational cost for the modeling of nanostructures.

  2. A multiband radiometer and data acquisition system for remote sensing field research

    NASA Technical Reports Server (NTRS)

    Bauer, M. E. (Principal Investigator); Robinson, B. F.; Dewitt, D. P.; Silva, L. F.; Vanderbilt, V. C.

    1981-01-01

    Specifications are described for a recently developed prototype multispectral data acquisition system which consists of multiband radiometer with 8 bands between 0.4 and 12.5 micrometers and a data recording module to record data from the radometer and ancillary sources. The systems is adaptable to helicopter, truck, or tripod platforms, as well as hand-held operation. The general characteristics are: (1) comparatively inexpensive to acquire, maintain and operate; (2) simple to operate and calibrate; (3) complete with data hardware and software; and (4) well documented for use by researchers. The instrument system is to be commercially available and can be utilized by many researchers to obtain large numbers of accurate, calibrated spectral measurements. It can be a key element in improving and advancing the capability for field research in remote sensing.

  3. Multi-band metamaterial absorber based on the arrangement of donut-type resonators.

    PubMed

    Park, Jin Woo; Tuong, Pham Van; Rhee, Joo Yull; Kim, Ki Won; Jang, Won Ho; Choi, Eun Ha; Chen, Liang Yao; Lee, YoungPak

    2013-04-22

    We propose multi-band metamaterial absorbers at microwave frequencies. The design, the analysis, the fabrication, and the measurement of the absorbers working in multiple bands are presented. The numerical simulations and the experiments in the microwave anechoic chamber were performed. The metamaterial absorbers consist of an delicate arrangement of donut-shape resonators with different sizes and a metallic background plane, separated by a dielectric. The near-perfect absorptions of dual, triple and quad peaks are persistent with polarization independence, and the effect of angle of incidence for both TE and TM modes was also elucidated. It was also found that the multiple-reflection theory was not suitable for explaining the absorption mechanism of our investigated structures. The results of this study are promising for the practical applications. PMID:23609678

  4. Cross-correlation and image alignment for multi-band IR sensors

    NASA Astrophysics Data System (ADS)

    Lu, Thomas; Chao, Tien-Hsin; Chen, Kang (Frank); Luong, Andrew; Dewees, Mallory; Yan, Xinyi; Chow, Edward; Torres, Gilbert

    2016-04-01

    We present the development of a cross-correlation algorithm for correlating objects in the long wave, mid wave and short wave Infrared sensor arrays. The goal is to align the images in the multisensor suite by correlating multiple key features in the images. Due to the wavelength differences, the object appears very differently in the sensor images even the sensors focus on the same object. In order to perform accurate correlation of the same object in the multi-band images, we perform image processing on the images so that the features of the object become similar to each other. Fourier domain band pass filters are used to enhance the images. Mexican Hat and Gaussian Derivative Wavelets are used to further enhance the features of the object. A Python based QT graphical user interface has been implemented to carry out the process. We show reliable results of the cross-correlation of the objects in multiple band videos.

  5. Strong interaction between electrons and collective excitations in the multiband superconductor MgB2

    DOE PAGESBeta

    Mou, Daixiang; Jiang, Rui; Taufour, Valentin; Flint, Rebecca; Bud'ko, S. L.; Canfield, P. C.; Wen, J. S.; Xu, Z. J.; Gu, Genda; Kaminski, Adam

    2015-04-08

    We use a tunable laser angle-resolved photoemission spectroscopy to study the electronic properties of the prototypical multiband BCS superconductor MgB2. Our data reveal a strong renormalization of the dispersion (kink) at ~65meV, which is caused by the coupling of electrons to the E2g phonon mode. In contrast to cuprates, the 65 meV kink in MgB2 does not change significantly across Tc. More interestingly, we observe strong coupling to a second, lower energy collective mode at a binding energy of 10 meV. As a result, this excitation vanishes above Tc and is likely a signature of the elusive Leggett mode.

  6. Star formation in M33 from HST multi-band imaging

    NASA Astrophysics Data System (ADS)

    Tolea, A.; Bianchi, L.

    2004-12-01

    We present results from an on-going study of stellar populations in the Local Group Galaxy M33. By comparing the multi-band photometry to model colors, we derive effective temperature and luminosity of the stellar objects, and information on the extinction by dust, in 27 fields sampling different environments across the galaxy. Two methods are used and the results compared. The stellar physical parameters are used to characterize the stellar populations in the observed fields which include several OB associations. We also reveal several massive star candidates. For more information and preprints, see http://dolomiti.pha.jhu.edu The work was supported by NASA grants HST-GO-9127 and NAG5-9219.

  7. Digital signal processing (DSP) applications for multiband loudness correction digital hearing aids and cochlear implants.

    PubMed

    Dillier, N; Frölich, T; Kompis, M; Bögli, H; Lai, W K

    1993-01-01

    Single-chip digital signal processors (DSPs) allow the flexible implementation of a large variety of speech analysis, synthesis, and processing algorithms for the hearing impaired. A series of experiments was carried out to optimize parameters of the adaptive beamformer noise reduction algorithm and to evaluate its performance in realistic environments with normal-hearing and hearing-impaired subjects. An experimental DSP system has been used to implement a multiband loudness correction (MLC) algorithm for a digital hearing aid. Speech tests in quiet and noise with 13 users of conventional hearing aids demonstrated significant improvements in discrimination scores with the MLC algorithm. Various speech coding strategies for cochlear implants were implemented in real time on a DSP laboratory speech processor. Improved speech discrimination performance was achieved with high-rate stimulation. Hybrid strategies incorporating speech feature detectors and complex decision algorithms are currently being investigated. PMID:8263833

  8. First-order phase transition and tricritical point in multiband U (1 ) London superconductors

    NASA Astrophysics Data System (ADS)

    Sellin, Karl A. H.; Babaev, Egor

    2016-02-01

    The order of the superconducting phase transition is a classical problem. Single-component type-2 superconductors exhibit a continuous "inverted-X Y " phase transition, as was first demonstrated for U (1 ) lattice London superconductors by a celebrated duality mapping with subsequent backing by numerical simulations. Here we study this problem in multiband U (1 ) London superconductors and find evidence that by contrast the model has a tricritical point. The superconducting phase transition becomes first order when the Josephson length is sufficiently large compared to the magnetic field penetration length. We present evidence that the fluctuation-induced dipolar interaction between vortex loops makes the phase transition discontinuous. We discuss that this mechanism is also relevant for the phase transitions in multicomponent gauge theories with higher broken symmetry.

  9. Performance evaluation and calibration of a modular multiband radiometer for remote sensing field research

    NASA Technical Reports Server (NTRS)

    Robinson, B. F.; Buckley, R. E.; Burgess, J. A. (Principal Investigator)

    1982-01-01

    A multiband radiometer suitable for operation from helicopter, small plane, truck, or tripod platforms was developed. The standard unit is equipped with the seven thematic mapper spectral bands with an added band from 1.5 to 1.30 microns; however, up to eight user specified bands from 0.4 to 15 microns may be installed under clean field conditions. Results of prototype tests of the spectral responsivity of the detectors, the transmittance of the optical filters as a function of wavelength, the fields of view, and the system linearity, temperature stability, noise performance, and dynamic range were evaluated. Minor modifications were made to the instrument and the results of final testing are reported.

  10. Multi-Band Multi-Tone Tunable Millimeter-Wave Frequency Synthesizer For Satellite Beacon Transmitter

    NASA Technical Reports Server (NTRS)

    Simons, Rainee N.; Wintucky, Edwin G.

    2016-01-01

    This paper presents the design and test results of a multi-band multi-tone tunable millimeter-wave frequency synthesizer, based on a solid-state frequency comb generator. The intended application of the synthesizer is in a satellite beacon transmitter for radio wave propagation studies at K-band (18 to 26.5 GHz), Q-band (37 to 42 GHz), and E-band (71 to 76 GHz). In addition, the architecture for a compact beacon transmitter, which includes the multi-tone synthesizer, polarizer, horn antenna, and power/control electronics, has been investigated for a notional space-to-ground radio wave propagation experiment payload on a small satellite. The above studies would enable the design of robust high throughput multi-Gbps data rate future space-to-ground satellite communication links.

  11. Short term and multi-band variability of the active nucleus of IC310

    NASA Astrophysics Data System (ADS)

    Eisenacher, Dorit; Colin, Pierre; Lombardi, Saverio; Sitarek, Julian; Zandanel, Fabio; MAGIC Collaboration; Paneque, David; Fermi-LAT Collaboration; Dauser, Thomas; Krauß, Felicia; Wilbert, Sven; Kadler, Matthias; Schulz, Robert; Wilms, Joern; Bach, Uwe; Ros, Eduardo

    2012-12-01

    The MAGIC Telescopes detected the active galaxy IC 310 at very high energies (VHE, >100 GeV) during observations of the Perseus cluster in 2009 and 2010. This source had originally been classified as a head-tail radio galaxy. By contrast, recent high-resolution radio images obtained with the VLBA reveal the blazar-like structure of IC 310 on parsec scales. This object is also investigated in terms of its variability at X-ray and gamma-ray energies. Studies of the multi-band flux variability at different time periods are presented. The spectral evolution seems to be different in the VHE gamma-ray and X-ray bands.

  12. Evaluation of Multiband EPI Acquisitions for Resting State fMRI.

    PubMed

    Preibisch, Christine; Castrillón G, J Gabriel; Bührer, Martin; Riedl, Valentin

    2015-01-01

    Functional magnetic resonance imaging (fMRI) and particularly resting state fMRI (rs-fMRI) is widely used to investigate resting state brain networks (RSNs) on the systems level. Echo planar imaging (EPI) is the state-of-the-art imaging technique for most fMRI studies. Therefore, improvements of EPI might lead to increased sensitivity for a large amount of studies performed every day. A number of developments to shorten acquisition time have been recently proposed and the multiband technique, allowing the simultaneous acquisition of multiple slices yielding an equivalent reduction of measurement time, is the most promising among them. While the prospect to significantly reduce acquisition time by means of high multiband acceleration factors (M) appears tempting, signal quality parameters and the sensitivity to detect common RSNs with increasing M-factor have only been partially investigated up to now. In this study, we therefore acquired rs-fMRI data from 20 healthy volunteers to systematically investigate signal characteristics and sensitivity for brain network activity in datasets with increasing M-factor, M = 2 - 4. Combined with an inplane, sensitivity encoding (SENSE), acceleration factor, S = 2, we applied a maximal acceleration factor of 8 (S2×M4). Our results suggest that an M-factor of 2 (total acceleration of 4) only causes negligible SNR decrease but reveals common RSN with increased sensitivity and stability. Further M-factor increase produced random artifacts as revealed by signal quality measures that may affect interpretation of RSNs under common scanning conditions. Given appropriate hardware, a mb-EPI sequence with a total acceleration of 4 significantly reduces overall scanning time and clearly increases sensitivity to detect common RSNs. Together, our results suggest mb-EPI at moderate acceleration factors as a novel standard for fMRI that might increase our understanding of network dynamics in healthy and diseased brains. PMID:26375666

  13. MULTIBAND OPTICAL OBSERVATION OF THE P/2010 A2 DUST TAIL

    SciTech Connect

    Kim, Junhan; Ishiguro, Masateru; Hanayama, Hidekazu; Hasegawa, Sunao; Usui, Fumihiko; Sarugaku, Yuki; Yanagisawa, Kenshi; Watanabe, Jun-ichi; Yoshida, Michitoshi

    2012-02-10

    An inner main-belt asteroid, P/2010 A2, was discovered on 2010 January 6. Based on its orbital elements, it is considered that the asteroid belongs to the Flora collisional family, where S-type asteroids are common, while showing a comet-like dust tail. Although analysis of images taken by the Hubble Space Telescope and Rosetta spacecraft suggested that the dust tail resulted from a recent head-on collision between asteroids, an alternative idea of ice sublimation was suggested based on the morphological fitting of ground-based images. Here, we report a multiband observation of P/2010 A2 made on 2010 January with a 105 cm telescope at the Ishigakijima Astronomical Observatory. Three broadband filters, g', R{sub c} , and I{sub c} , were employed for the observation. The unique multiband data reveal that the reflectance spectrum of the P/2010 A2 dust tail resembles that of an Sq-type asteroid or that of ordinary chondrites rather than that of an S-type asteroid. Due to the large error of the measurement, the reflectance spectrum also resembles the spectra of C-type asteroids, even though C-type asteroids are uncommon in the Flora family. The reflectances relative to the g' band (470 nm) are 1.096 {+-} 0.046 at the R{sub c} band (650 nm) and 1.131 {+-} 0.061 at the I{sub c} band (800 nm). We hypothesize that the parent body of P/2010 A2 was originally S-type but was then shattered upon collision into scattering fresh chondritic particles from the interior, thus forming the dust tail.

  14. Evaluation of Multiband EPI Acquisitions for Resting State fMRI

    PubMed Central

    Bührer, Martin; Riedl, Valentin

    2015-01-01

    Functional magnetic resonance imaging (fMRI) and particularly resting state fMRI (rs-fMRI) is widely used to investigate resting state brain networks (RSNs) on the systems level. Echo planar imaging (EPI) is the state-of-the-art imaging technique for most fMRI studies. Therefore, improvements of EPI might lead to increased sensitivity for a large amount of studies performed every day. A number of developments to shorten acquisition time have been recently proposed and the multiband technique, allowing the simultaneous acquisition of multiple slices yielding an equivalent reduction of measurement time, is the most promising among them. While the prospect to significantly reduce acquisition time by means of high multiband acceleration factors (M) appears tempting, signal quality parameters and the sensitivity to detect common RSNs with increasing M-factor have only been partially investigated up to now. In this study, we therefore acquired rs-fMRI data from 20 healthy volunteers to systematically investigate signal characteristics and sensitivity for brain network activity in datasets with increasing M-factor, M = 2 − 4. Combined with an inplane, sensitivity encoding (SENSE), acceleration factor, S = 2, we applied a maximal acceleration factor of 8 (S2×M4). Our results suggest that an M-factor of 2 (total acceleration of 4) only causes negligible SNR decrease but reveals common RSN with increased sensitivity and stability. Further M-factor increase produced random artifacts as revealed by signal quality measures that may affect interpretation of RSNs under common scanning conditions. Given appropriate hardware, a mb-EPI sequence with a total acceleration of 4 significantly reduces overall scanning time and clearly increases sensitivity to detect common RSNs. Together, our results suggest mb-EPI at moderate acceleration factors as a novel standard for fMRI that might increase our understanding of network dynamics in healthy and diseased brains. PMID:26375666

  15. Variation of sodium on Mercury with solar radiation pressure

    NASA Technical Reports Server (NTRS)

    Potter, A. E.; Morgan, T. H.

    1987-01-01

    It has been suggested that nonthermal Na atoms with velocities in excess of 2.1 km/sec in the Mercury atmosphere can be accelerated off the planet by solar radiation pressure; Na abundance may accordingly be expected to decrease with increasing radiation pressure. While this is confirmed by the present measurements, high resolution line profile measurements on Na emission indicate that very little, if any, of the Na is nonthermal, while the bulk is at a temperature approaching that of the planetary surface. Attention is given to explanations for the observed variation.

  16. The behavior of beams of relativistic non-thermal electrons under the influence of collisions and synchrotron losses

    NASA Technical Reports Server (NTRS)

    Mctiernan, James M.; Petrosian, Vahe

    1989-01-01

    For many astrophysical situations, such as in solar flares or cosmic gamma-ray bursts, continuum gamma rays with energies up to hundreds of MeV were observed, and can be interpreted to be due to bremsstrahlung radiation by relativistic electrons. The region of acceleration for these particles is not necessarily the same as the region in which the radiation is produced, and the effects of the transport of the electrons must be included in the general problem. Hence it is necessary to solve the kinetic equation for relativistic electrons, including all the interactions and loss mechanisms relevant at such energies. The resulting kinetic equation for non-thermal electrons, including the effects of Coulomb collisions and losses due to synchrotron emission, was solved analytically in some simple limiting cases, and numerically for the general cases including constant and varying background plasma density and magnetic field. New approximate analytic solutions are presented for collision dominated cases, for small pitch angles and all energies, synchrotron dominated cases, both steady-state and time dependent, for all pitch angles and energies, and for cases when both synchrotron and collisional energy losses are important, but for relativistic electrons. These analytic solutions are compared to the full numerical results in the proper limits. These results will be useful for calculation of spectra and angular distribution of the radiation (x rays, gamma-rays, and microwaves) emitted via synchrotron or bremsstrahlung processes by the electrons. These properties and their relevance to observations will be observed in subsequent papers.

  17. Lunar central peak mineralogy and iron content using the Kaguya Multiband Imager: Reassessment of the compositional structure of the lunar crust

    NASA Astrophysics Data System (ADS)

    Lemelin, Myriam; Lucey, Paul G.; Song, Eugenie; Taylor, G. Jeffrey

    2015-05-01

    Ryder and Wood (1977) suggested that the lunar crust becomes more mafic with depth because the impact melts associated with the large Imbrium and Serenitatis basins are more mafic than the surface composition of the Moon. In this study, we reexamine the hypothesis that the crust becomes more mafic with depth; we analyze the composition of crater central peaks by using recent remote sensing data and combining the best practices of previous studies. We compute the mineralogy for 34 central peaks using (1) nine-band visible and near-infrared data from the Kaguya Multiband Imager, (2) an improved version of Hapke's radiative transfer model validated with spectra of lunar soils with well-known modal mineralogy, and (3) new crustal thickness models from the Gravity Recovery and Interior Laboratory data to examine the variation in composition with depth. We find that there is no increase in mafic mineral abundances with proximity to the crust/mantle boundary or with depth from the current lunar surface and, therefore, that the crust does not become more mafic with depth. We find that anorthosite with very low mafic abundance ("purest anorthosite" or PAN) is a minority constituent in these peaks, and there is no clear evidence of a distinct PAN-rich layer in the middle crust as previously proposed. The composition of most of the central peaks we analyze is more mafic than classically defined anorthosites with an average noritic anorthosite composition similar to that of the lunar surface.

  18. Intrinsic Josephson junctions in the iron-based multi-band superconductor (V2Sr4O6)Fe2As2

    NASA Astrophysics Data System (ADS)

    Moll, Philip J. W.; Zhu, Xiyu; Cheng, Peng; Wen, Hai-Hu; Batlogg, Bertram

    2014-09-01

    In layered superconductors, Josephson junctions may be formed within the unit cell as a result of sufficiently low inter-layer coupling. These intrinsic Josephson junction (iJJ) systems have attracted considerable interest for their application potential in quantum computing as well as efficient sources of THz radiation, closing the famous `THz gap'. So far, iJJ have been demonstrated in single-band, copper-based high-Tc superconductors, mainly in Bi-Sr-Ca-Cu-O (refs , , ). Here we report clear experimental evidence for iJJ behaviour in the iron-based superconductor (V2Sr4O6)Fe2As2. The intrinsic junctions are identified by periodic oscillations of the flux-flow voltage on increasing a well-aligned in-plane magnetic field. The periodicity is explained by commensurability effects between the Josephson vortex lattice and the crystal structure, which is a hallmark signature of Josephson vortices confined into iJJ stacks. This finding adds the pnictide (V2Sr4O6)Fe2As2 to the copper-based iJJ materials of interest for Josephson junction applications. In particular, novel devices based on multi-band Josephson coupling may be realized.

  19. Monitoring System for Atmospheric Water Vapor with a Ground-Based Multi-Band Radiometer: Meteorological Application of Radio Astronomy Technologies

    NASA Astrophysics Data System (ADS)

    Nagasaki, T.; Araki, K.; Ishimoto, H.; Kominami, K.; Tajima, O.

    2016-08-01

    High-resolution estimation of thermodynamic properties in the atmosphere can help to predict and mitigate meteorological disasters, such as local heavy rainfall and tornadic storms. For the purposes of short-term forecasting and nowcasting of severe storms, we propose a novel ground-based measurement system, which observes the intensity of atmospheric radiation in the microwave range. Our multi-band receiver system is designed to identify a rapid increase in water vapor before clouds are generated. At frequencies between 20 and 30 GHz, our system simultaneously measures water vapor as a broad absorption peak at 22 GHz as well as cloud liquid water. Another band at 50-60 GHz provides supplementary information from oxygen radiation to give vertical profiles of physical temperature. For the construction of this cold receiver system, novel technologies originally developed for observations of cosmic microwave background radiation were applied. The input atmospheric signal is amplified by a cold low-noise amplifier maintained below 10 K, while the spectrum of this amplified signal is measured using a signal analyzer under ambient conditions. The cryostat also contains a cold black body at 40 K to act as a calibration signal. This calibration signal is transported to each of the receivers via a wire grid. We can select either the atmospheric signal or the calibration signal by changing the orientation of this wire. Each receiver can be calibrated using this setup. Our system is designed to be compact (<1 m3), with low power consumption (˜ 1.5 kW). Therefore, it is easy to deploy on top of high buildings, mountains, and ship decks.

  20. Monitoring System for Atmospheric Water Vapor with a Ground-Based Multi-Band Radiometer: Meteorological Application of Radio Astronomy Technologies

    NASA Astrophysics Data System (ADS)

    Nagasaki, T.; Araki, K.; Ishimoto, H.; Kominami, K.; Tajima, O.

    2015-12-01

    High-resolution estimation of thermodynamic properties in the atmosphere can help to predict and mitigate meteorological disasters, such as local heavy rainfall and tornadic storms. For the purposes of short-term forecasting and nowcasting of severe storms, we propose a novel ground-based measurement system, which observes the intensity of atmospheric radiation in the microwave range. Our multi-band receiver system is designed to identify a rapid increase in water vapor before clouds are generated. At frequencies between 20 and 30 GHz, our system simultaneously measures water vapor as a broad absorption peak at 22 GHz as well as cloud liquid water. Another band at 50-60 GHz provides supplementary information from oxygen radiation to give vertical profiles of physical temperature. For the construction of this cold receiver system, novel technologies originally developed for observations of cosmic microwave background radiation were applied. The input atmospheric signal is amplified by a cold low-noise amplifier maintained below 10 K, while the spectrum of this amplified signal is measured using a signal analyzer under ambient conditions. The cryostat also contains a cold black body at 40 K to act as a calibration signal. This calibration signal is transported to each of the receivers via a wire grid. We can select either the atmospheric signal or the calibration signal by changing the orientation of this wire. Each receiver can be calibrated using this setup. Our system is designed to be compact (< 1 m3 ), with low power consumption (˜ 1.5 kW). Therefore, it is easy to deploy on top of high buildings, mountains, and ship decks.

  1. Observing the Non-Thermal Universe with the Highest Energy Photons

    NASA Astrophysics Data System (ADS)

    Dingus, Brenda L.; HAWC, VERITAS, CTA

    2016-01-01

    Astrophysical sources of relativistic particles radiate gamma rays to such high energies that they can be detected from the ground. The existence of high energy gamma rays implies that even higher energy particles are being accelerated placing strong constraints on these non-thermal accelerators. Within our galaxy, TeV gamma rays have been detected from supernova remnants, pulsar wind nebula, x-ray binaries and some yet to be identified sources in the Galactic plane. In addition, these gamma rays have sufficient energy to be attenuated by the interaction with infrared photons producing an electron-positron pair. Thus the spectrum of gamma rays can also constrain the infrared photon density, which for distant extragalactic sources is a direct probe of cosmology. The known extragalactic TeV sources are primarily the blazer class of active galactic nuclei. And TeV gamma rays might even be produced by annihilating dark matter.The US currently supports two ground-based gamma-ray observatories—HAWC and VERITAS—and NSF is developing a prototype for the international Cherenkov Telescope Array (CTA) observatory. The HAWC (High Altitude Water Cherenkov) observatory just began operation of the full detector in March 2015 and with its wide field of view scans ~2/3 of the sky each day for TeV sources. VERITAS (Very EneRgetic Imaging Telescope Array System) is an array of four imaging atmospheric Cherenkov telescopes that follows individual sources to produce lightcurves and spectra from 85 GeV to > 30 TeV. The combination of both a survey and pointed observatory is very complementary with a broad scientific reach that includes the study of extragalactic and Galactic objects as well as the search for astrophysical signatures of dark matter and the measurement of cosmic rays. I will present the current view of the TeV sky and the latest results from HAWC and VERITAS as well as plans for CTA.

  2. Lecture on Thermal Radiation

    NASA Technical Reports Server (NTRS)

    Dennis, Brian R.

    2006-01-01

    This lecture will cover solar thermal radiation, particularly as it relates to the high energy solar processes that are the subject of this summer school. After a general review of thermal radiation from the Sun and a discussion of basic definitions, the various emission and absorption mechanisms will be described including black-body emission, bremsstrahlung, free-bound, and atomic line emissions of all kinds. The bulk of the time will be spent discussing the observational characteristics of thermal flare plasma and what can be learned about the flare energy release process from observations of the thermal radiation at all wavelengths. Information that has been learned about the morphology, temperature distribution, and composition of the flare plasma will be presented. The energetics of the thermal flare plasma will be discussed in relation to the nonthermal energy of the particles accelerated during the flare. This includes the total energy, the radiated and conductive cooling processes, and the total irradiated energy.

  3. Mitochondria-Mediated Anticancer Effects of Non-Thermal Atmospheric Plasma

    PubMed Central

    Zhunussova, Aigul; Vitol, Elina A.; Polyak, Boris; Tuleukhanov, Sultan; Brooks, Ari D.; Sensenig, Richard; Friedman, Gary; Orynbayeva, Zulfiya

    2016-01-01

    Non-thermal atmospheric pressure plasma has attracted great interest due to its multiple potential biomedical applications with cancer treatment being among the most urgent. To realize the clinical potential of non-thermal plasma, the exact cellular and molecular mechanisms of plasma effects must be understood. This work aimed at studying the prostate cancer specific mechanisms of non-thermal plasma effects on energy metabolism as a central regulator of cell homeostasis and proliferation. It was found that cancer cells with higher metabolic rate initially are more resistant to plasma treated phosphate-buffered saline (PBS) since the respiratory and calcium sensitive signaling systems were not responsive to plasma exposure. However, dramatic decline of cancer oxidative phosphorylation developed over time resulted in significant progression of cell lethality. The normal prostate cells with low metabolic activity immediately responded to plasma treated PBS by suppression of respiratory functions and sustained elevation of cytosolic calcium. However, over time the normal cells start recovering their mitochondria functions, proliferate and restore the cell population. We found that the non-thermal plasma induced increase in intracellular ROS is of primarily non-mitochondrial origin. The discriminate non-thermal plasma effects hold a promise for clinical cancer intervention. PMID:27270230

  4. Non-thermal Dupree diffusivity and shielding effects on atomic collisions in Lorentzian turbulent plasmas

    NASA Astrophysics Data System (ADS)

    Lee, Myoung-Jae; Jung, Young-Dae

    2016-05-01

    The influence of non-thermal Dupree turbulence and the plasma shielding on the electron-ion collision is investigated in Lorentzian turbulent plasmas. The second-order eikonal analysis and the effective interaction potential including the Lorentzian far-field term are employed to obtain the eikonal scattering phase shift and the eikonal collision cross section as functions of the diffusion coefficient, impact parameter, collision energy, Debye length and spectral index of the astrophysical Lorentzian plasma. It is shown that the non-thermal effect suppresses the eikonal scattering phase shift. However, it enhances the eikonal collision cross section in astrophysical non-thermal turbulent plasmas. The effect of non-thermal turbulence on the eikonal atomic collision cross section is weakened with increasing collision energy. The variation of the atomic cross section due to the non-thermal Dupree turbulence is also discussed. This research was supported by Nuclear Fusion Research Program through NRF funded by the Ministry of Science, ICT & Future Planning (Grant No. 2015M1A7A1A01002786).

  5. Enhanced vibrational spectroscopy, intracellular refractive indexing for label-free biosensing and bioimaging by multiband plasmonic-antenna array.

    PubMed

    Chen, Cheng-Kuang; Chang, Ming-Hsuan; Wu, Hsieh-Ting; Lee, Yao-Chang; Yen, Ta-Jen

    2014-10-15

    In this study, we report a multiband plasmonic-antenna array that bridges optical biosensing and intracellular bioimaging without requiring a labeling process or coupler. First, a compact plasmonic-antenna array is designed exhibiting a bandwidth of several octaves for use in both multi-band plasmonic resonance-enhanced vibrational spectroscopy and refractive index probing. Second, a single-element plasmonic antenna can be used as a multifunctional sensing pixel that enables mapping the distribution of targets in thin films and biological specimens by enhancing the signals of vibrational signatures and sensing the refractive index contrast. Finally, using the fabricated plasmonic-antenna array yielded reliable intracellular observation was demonstrated from the vibrational signatures and intracellular refractive index contrast requiring neither labeling nor a coupler. These unique features enable the plasmonic-antenna array to function in a label-free manner, facilitating bio-sensing and imaging development. PMID:24836017

  6. Over 210 Gb/s PDM multiband DDO-OFDM LR-PON downstream with simple self-polarization diversity.

    PubMed

    Chen, You-Wei; Yan, Jhih-Heng; Wang, Yu-Mao; Chang, Mu-Fan; Peng, Wei-Ren; Feng, Kai-Ming

    2015-07-13

    A simple polarization division multiplexed (PDM) multiband direct-detection optical orthogonal frequency division multiplexing (DDO-OFDM) long reach passive optical network (LR-PON) with net data rate over 210 Gb/s on single wavelength channel is proposed and experimentally demonstrated with self-polarization diversity technique. The proposed self-polarization diversity function is realized at a powered remote node with all passive components to achieve cost-effectiveness and simultaneously double both the channel capacity and subscriber numbers. Meanwhile, this architecture retains the simplicity of direct-detection single receiver-end without any hardware or software modification at the optical network units. The measured power penalty of the proposed PDM multiband DDO-OFDM LR-PON is 0.8 dB over 100 km transmission with respect to that of the ordinary single polarization scheme at a specified forward error correction threshold. PMID:26191911

  7. Momentum dependence of the superconducting gap and in-gap states in MgB2 multiband superconductor

    DOE PAGESBeta

    Mou, Daixiang; Jiang, Rui; Taufour, Valentin; Bud'ko, S. L.; Canfield, P. C.; Kaminski, Adam

    2015-06-29

    We use tunable laser-based angle-resolved photoemission spectroscopy to study the electronic structure of the multiband superconductor MgB2. These results form the baseline for detailed studies of superconductivity in multiband systems. We find that the magnitude of the superconducting gap on both σ bands follows a BCS-like variation with temperature with Δ0 ~ 7meV. Furthermore, the value of the gap is isotropic within experimental uncertainty and in agreement with a pure s-wave pairing symmetry. We observe in-gap states confined to kF of the σ band that occur at some locations of the sample surface. As a result, the energy of thismore » excitation, ~ 3 meV, was found to be somewhat larger than the previously reported gap on π Fermi sheet and therefore we cannot exclude the possibility of interband scattering as its origin.« less

  8. Design of a 0.18 μm CMOS multi-band compatible low power GNSS receiver RF frontend

    NASA Astrophysics Data System (ADS)

    Bing, Li; Yiqi, Zhuang; Qiang, Long; Zhao, Jin; Zhenrong, Li; Gang, Jin

    2011-03-01

    This paper presents the design and implementation of a fully integrated multi-band RF receiver frontend for GNSS applications on L-band. A single RF signal channel with a low-IF architecture is adopted for multi-band operation on the RF section, which mainly consists of a low noise amplifier (LNA), a down-converter, polyphase filters and summing circuits. An improved cascode source degenerated LNA with a multi-band shared off-chip matching network and band switches is implemented in the first amplifying stage. Also, a re-designed wideband double balance mixer is implemented in the down conversion stage, which provides better gain, noise figure and linearity performances. Using a TSMC 0.18 μm 1P4M RF CMOS process, a compact 1.27 GHz/1.575 GHz dual-band GNSS frontend is realized in the proposed low-IF topology. The measurements exhibit the gains of 45 dB and 43 dB, and noise figures are controlled at 3.35 dB and 3.9 dB of the two frequency bands, respectively. The frontend model consumes about 11.8-13.5 mA current on a 1.8 V power supply. The core occupies 1.91 × 0.53 mm2 while the total die area with ESD is 2.45 × 2.36 mm2.

  9. Nodal structure of the order parameters in multiband and nonsymmorphic superconductors: iron-based superconductors as a case study

    NASA Astrophysics Data System (ADS)

    Kharitonov, Maxim; Kotliar, Gabriel

    2014-03-01

    We generalize the group-theoretical method of determining the symmetry-enforced nodes of superconducting order parameters to materials with multiple active electron bands and nonsymmorphic space groups. We apply this procedure in detail to the 11/111/1111 families of iron-based superconductors, which feature both of these properties. We arrive at a general conclusion that in a generic scenario of ``multiband superconductivity'', when Cooper pairing between various electron bands is allowed, an order parameter of any symmetry can be nodeless in the whole Brillouin zone: the nodes that would be present in a single-band scenario can be completely lifted in a multiband scenario. However, such regime requires interband pairing and certain energetic conditions must be met for this to occur. When combined with the information about the band structure from experiments or numerics, our method provides concrete guidelines for deducing the symmetry of the order parameters realized in real multiband superconductors; implications for iron-based superconductors are discussed.

  10. Multi-band morpho-Spectral Component Analysis Deblending Tool (MuSCADeT): Deblending colourful objects

    NASA Astrophysics Data System (ADS)

    Joseph, R.; Courbin, F.; Starck, J.-L.

    2016-05-01

    We introduce a new algorithm for colour separation and deblending of multi-band astronomical images called MuSCADeT which is based on Morpho-spectral Component Analysis of multi-band images. The MuSCADeT algorithm takes advantage of the sparsity of astronomical objects in morphological dictionaries such as wavelets and their differences in spectral energy distribution (SED) across multi-band observations. This allows us to devise a model independent and automated approach to separate objects with different colours. We show with simulations that we are able to separate highly blended objects and that our algorithm is robust against SED variations of objects across the field of view. To confront our algorithm with real data, we use HST images of the strong lensing galaxy cluster MACS J1149+2223 and we show that MuSCADeT performs better than traditional profile-fitting techniques in deblending the foreground lensing galaxies from background lensed galaxies. Although the main driver for our work is the deblending of strong gravitational lenses, our method is fit to be used for any purpose related to deblending of objects in astronomical images. An example of such an application is the separation of the red and blue stellar populations of a spiral galaxy in the galaxy cluster Abell 2744. We provide a python package along with all simulations and routines used in this paper to contribute to reproducible research efforts. Codes can be found at http://lastro.epfl.ch/page-126973.html

  11. Ion Streaming Instabilities in Pair Ion Plasma and Localized Structure with Non-Thermal Electrons

    NASA Astrophysics Data System (ADS)

    Nasir Khattak, M.; Mushtaq, A.; Qamar, A.

    2015-12-01

    Pair ion plasma with a fraction of non-thermal electrons is considered. We investigate the effects of the streaming motion of ions on linear and nonlinear properties of unmagnetized, collisionless plasma by using the fluid model. A dispersion relation is derived, and the growth rate of streaming instabilities with effect of streaming motion of ions and non-thermal electrons is calculated. A qausi-potential approach is adopted to study the characteristics of ion acoustic solitons. An energy integral equation involving Sagdeev potential is derived during this process. The presence of the streaming term in the energy integral equation affects the structure of the solitary waves significantly along with non-thermal electrons. Possible application of the work to the space and laboratory plasmas are highlighted.

  12. Hydrogen and deuterium loss from the terrestrial atmosphere - A quantitative assessment of nonthermal escape fluxes

    NASA Technical Reports Server (NTRS)

    Yung, Yuk L.; Wen, Jun-Shan; Moses, Julianne I.; Landry, Bridget M.; Allen, Mark; Hsu, Kuang-Jung

    1989-01-01

    A comprehensive one-dimensional photochemical model extending from the middle atmosphere (50 km) to the exobase (432 km) has been used to study the escape of hydrogen and deuterium from the earth's atmosphere. The model incorporates recent advances in chemical kinetics as well as atmospheric observations by satellites, especially the Atmosphere Explorer C satellite. The results suggest that the escape fluxes of both H and D are limited by the upward transport of total hydrogen and total deuterium at the homopause. About one fourth of total hydrogen escape is thermal, the rest being nonthermal. It is shown that escape of D is nonthermal and that charge exchange and polar wind are important mechanisms for the nonthermal escape of H and D.

  13. The Advantages of Non-Thermal Plasma for Detonation Initiation Compared with Spark Plug

    NASA Astrophysics Data System (ADS)

    Zheng, Dianfeng

    2016-02-01

    In this paper, the characteristics of detonation combustion ignited by AC-driven non-thermal plasma and spark plug in air/acetylene mixture have been compared in a double-tube experiment system. The two tubes had the same structure, and their closed ends were installed with a plasma generator and a spark plug, respectively. The propagation characteristics of the flame were measured by pressure sensors and ion probes. The experiment results show that, compared with a spark plug, the non-thermal plasma obviously broadened the range of equivalence ratio when the detonation wave could develop successfully, it also heightened the pressure value of detonation wave. Meanwhile, the detonation wave development time and the entire flame propagation time were reduced by half. All of these advantages benefited from the larger ignition volume when a non-thermal plasma was applied. supported by National Natural Science Foundation of China (No. 51176001)

  14. Role of nonthermal electrons on dust ion acoustic double layer with variable dust charge

    NASA Astrophysics Data System (ADS)

    Borah, Prathana; Gogoi, Deepshikha; Das, Nilakshi

    2016-01-01

    The presence of nonthermal electron may play an important role in the formation of nonlinear structures in plasma. On the other hand, fluctuation of dust charge is an important and unique feature of complex plasma and it gives rise to a dissipative effect in the system leading to the formation of nonlinear structures due to the balance between nonlinearity and dissipation. In this paper, the propagation of nonlinear dust ion acoustic (DIA) wave in unmagnetized collisionless dusty plasma consisting of ions, nonthermal electrons and dust grains with variable negative charge has been investigated using the Sagdeev potential method. The existence domain of rarefactive double layer (DL) in the DIA wave has been investigated for the range of plasma parameters. The real potential has been obtained by numerically solving the Poisson equation and dust charging equation. It is observed that the presence of nonthermal electrons strengthens the DIA DL.

  15. Nonthermal Inactivation of Cronobacter sakazakii in Infant Formula Milk: A Review.

    PubMed

    Pina-Pérez, M C; Rodrigo, D; Martínez, A

    2016-07-26

    Up-to-date, nonthermal technologies and combinations of them, in accordance with the "hurdle technology" concept, are being applied by different research groups in response to calls by the International Food and Human Health Organizations (ESPGHAN, 2004; FAO/WHO, 2006, 2008) for alternatives to thermal control of Cronobacter sakazakii in reconstituted powdered infant formula milk. This review highlights (i) current knowledge on the application of nonthermal technologies to control C. sakazakii in infant formula milk and (ii) the importance of the application of nonthermal technologies for the control of C. sakazakii as part of the development of strategies in the context of improving food safety and quality of this product. PMID:25603362

  16. Effect of electron nonthermality on nonlinear electrostatic solitary waves in a charge varying dusty plasma

    SciTech Connect

    Tribeche, Mouloud; Boumezoued, Ghania

    2008-05-15

    The effect of nonthermal electrons with excess of fast energetic electrons on large amplitude electrostatic solitary waves is investigated in a charge varying dusty plasma. The correct nonthermal electron charging is investigated based on the orbit-motion-limited approach. It is found that the nonlinear localized potential structure shrinks when the electrons deviate from isothermality. The dust particles are locally expelled and pushed out the region of the soliton localization as the electrons evolve far away from their thermodynamic equilibrium. Under certain conditions, the dust charge fluctuation may provide an alternate physical mechanism causing anomalous dissipation, the strength of which becomes important and may prevail over that of dispersion as the value of the electron nonthermal parameter {alpha} increases.

  17. Dust-acoustic shock waves in a magnetized non-thermal dusty plasma

    NASA Astrophysics Data System (ADS)

    Shahmansouri, M.; Mamun, A. A.; Mamun

    2014-08-01

    A theoretical investigation is carried out to study the basic properties of dust-acoustic (DA) shock waves propagating in a magnetized non-thermal dusty plasma (containing cold viscous dust fluid, non-thermal ions, and non-thermal electrons). The reductive perturbation method is used to derive the Korteweg-de Vries-Burgers equation. It is found that the basic properties of DA shock waves are significantly modified by the combined effects of dust fluid viscosity, external magnetic field, and obliqueness (angle between external magnetic field and DA wave propagation direction). It is shown that the dust fluid viscosity acts as a source of dissipation, and is responsible for the formation of DA shock structures in the dusty plasma system under consideration. The implications of our results in some space and laboratory plasma situations are briefly discussed.

  18. Effect of nonthermality fraction on dust acoustic growth rate in inhomogeneous viscous dusty plasmas

    NASA Astrophysics Data System (ADS)

    El-Shewy, E. K.; El-Wakil, S. A.; El-Hanbaly, A. M.; Sallah, M.; Darweesh, H. F.

    2015-04-01

    The properties of linear dust acoustic (DA) waves in inhomogeneous viscous dusty plasmas with non-thermal electrons and ions have been investigated. A linear dispersion relation is obtained with the non-adiabatic dust charge fluctuation and fraction of nonthermality of electron-ion. The dependence of frequency and the damping rate of waves on the nonthermality fraction and dust kinematic viscosity coefficient are discussed. To study the dust acoustic shock waves, KdV-Burgers (KdV-B) equation for homogeneous dissipative dusty plasma has been considered and solved by means of tanh method. The obtained solution is a particular combination of a solitary wave with a Burgers shock wave. The present results are useful in the context of space plasma.

  19. Digital Switching CMOS Power Amplifier for Multiband and Multimode Handset Applications

    NASA Astrophysics Data System (ADS)

    Nakatani, Toshifumi

    This thesis is directed towards the development of a digitally-assisted radio frequency power amplifier (RF PA) which is one of the potential solutions to realize a multiband and multimode transmitter with high efficiency for handset applications. To improve efficiency and linearity in multiple conditions, PA circuits and digital signal processing (DSP) algorithms are co-designed. In the dissertation, a proposed architecture employs a current-mode class-D (CMCD) configuration for high efficiency, and a polar modulation scheme driven by digital inputs. Detail design, fabrication and experimental results are given for circuit implementation and DSP of this architecture. First, a multiband watt-class complementary metal-oxide-semiconductor (CMOS) PA is demonstrated using 0.15 um CMOS integrated circuits (ICs), off-chip inductor and balun. To obtain high breakdown voltage, stacked field effect transistors (FETs) are used. The CMCD PA is tuned by band-switching capacitors, operating in the 0.7-1.8 GHz frequency band. The overall efficiencies of 27.1 / 25.6 % are achieved at 30.2 / 28.9 dBm CW output powers and 0.85 / 1.75 GHz carrier frequencies, respectively. Next, to achieve wide output power dynamic range, an architecture consisting of small segmented unti-cells is introduced into the PA, where multiple three-state unit-cells are used and the state of each unit-cell is controlled to provide a specific output power. The overall dynamic ranges are expanded to approximately 90 dB and 85 dB at and 0.85 / 1.75 GHz, respectively. The dissertation then presents digital modulation algorithms. The digital compensation techniques are developed to maintain linearity of an envelope modulator of the polar transmitter. A new digital pulse width modulation algorithm is also shown to partially suppress spurious signals associated with the digital input envelope signal. When wideband code-division multiple access (WCDMA) modulation is implemented, spur suppression of 9-10 dB is

  20. Cluster Merger Shock Constraints on Particle Acceleration and Nonthermal Pressure in the Intracluster Medium

    NASA Astrophysics Data System (ADS)

    Nakar, Ehud; Milosavljević, Miloš; Nagai, Daisuke

    2008-03-01

    X-ray observations of galaxy cluster merger shocks can be used to constrain nonthermal processes in the intracluster medium (ICM). The presence of nonthermal pressure components in the ICM, as well as the shock acceleration of particles and their escape, all affect shock jump conditions in distinct ways. Therefore, these processes can be constrained using X-ray surface brightness and temperature maps of merger shock fronts. Here we use these observations to place constraints on particle acceleration efficiency in intermediate Mach number (\\mathstrutM} ≈ 2 - 3) shocks and explore the potential to constrain the contribution of nonthermal components (e.g., cosmic rays, magnetic field, and turbulence) to ICM pressure in cluster outskirts. We model the hydrodynamic jump conditions in merger shocks discovered in the galaxy clusters A520 (\\mathstrutM} ≈ 2) and 1E 0657-56 (\\mathstrutM} ≈ 3) using a multifluid model comprising a thermal plasma, a nonthermal plasma, and a magnetic field. Based on the published X-ray spectroscopic data alone, we find that the fractional contribution of cosmic rays accelerated in these shocks is lesssim10% of the shock downstream pressure. Current observations do not constrain the fractional contribution of nonthermal components to the pressure of the undisturbed shock upstream. Future X-ray observations, however, have the potential to either detect particle acceleration in these shocks through its effect on the shock dynamics, or place a lower limit on the nonthermal pressure contributions in the undisturbed ICM. We briefly discuss implications for models of particle acceleration in collisionless shocks and the estimates of galaxy cluster masses derived from X-ray and Sunyaev-Zel'dovich effect observations.

  1. Thermal and Nonthermal X-Rays from the Large Magellanic Cloud Superbubble 30 Doradus C

    NASA Astrophysics Data System (ADS)

    Bamba, Aya; Ueno, Masaru; Nakajima, Hiroshi; Koyama, Katsuji

    2004-02-01

    We report on the discovery of thermal and nonthermal X-rays from the shells of the superbubble (SB) 30 Dor C in the LMC. The X-ray morphology is a nearly circular shell with a radius of ~40 pc, which is bright on the northern and western sides. The spectra of the shells differ from region to region. The southern shell shows clear emission lines and is well fitted with a model of a thin thermal plasma (kT=0.21 keV) in nonequilibrium ionization plus a power-law component. This thermal plasma is located inside of the Hα emission, which is the outer edge of the shell of the SB. The northern and western sides of the SB are dim in Hα emission but are bright in nonthermal (power-law) X-rays with a photon index of 2.1-2.9. The nonthermal X-ray shell traces the outer boundary of the radio shell. These features of thin thermal and nonthermal X-rays are similar to those of SN 1006, a prototype of a synchrotron X-ray shell, but the nonthermal component of 30 Dor C is about 10 times brighter than that of SN 1006. 30 Dor C is the first candidate of an extragalactic SB, in which energetic electrons are accelerating in the shell. The age is much older than that of SN 1006, and hence the particle acceleration time in this SB may be longer than those in normal shell-like supernova remnants. We found pointlike sources associated with some of the tight star clusters. The X-ray luminosity and spectrum are consistent with those of young clusters of massive stars. Pointlike sources with nonthermal spectra are also found in the SB. These may be background objects (active galactic nuclei) or stellar remnants (neutron stars or black holes).

  2. THE SWIFT BURST ALERT TELESCOPE PERSPECTIVE ON NON-THERMAL EMISSION IN HIFLUGCS GALAXY CLUSTERS

    SciTech Connect

    Wik, Daniel R.; Baumgartner, Wayne H.; Tueller, Jack; Okajima, Takashi; Zhang Yuying; Mushotzky, Richard F.; Clarke, Tracy E.

    2012-03-20

    The search for diffuse non-thermal, inverse Compton (IC) emission from galaxy clusters at hard X-ray energies has been underway for many years, with most detections being either of low significance or controversial. In this work, we investigate 14-195 keV spectra from the Swift Burst Alert Telescope (BAT) all-sky survey for evidence of non-thermal excess emission above the exponentially decreasing tail of thermal emission in the flux-limited HIFLUGCS sample. To account for the thermal contribution at BAT energies, XMM-Newton EPIC spectra are extracted from coincident spatial regions so that both thermal and non-thermal spectral components can be determined simultaneously. We find marginally significant IC components in six clusters, though after closer inspection and consideration of systematic errors we are unable to claim a clear detection in any of them. The spectra of all clusters are also summed to enhance a cumulative non-thermal signal not quite detectable in individual clusters. After constructing a model based on single-temperature fits to the XMM-Newton data alone, we see no significant excess emission above that predicted by the thermal model determined at soft energies. This result also holds for the summed spectra of various subgroups, except for the subsample of clusters with diffuse radio emission. For clusters hosting a diffuse radio halo, a relic, or a mini-halo, non-thermal emission is initially detected at the {approx}5{sigma} confidence level-driven by clusters with mini-halos-but modeling and systematic uncertainties ultimately degrade this significance. In individual clusters, the non-thermal pressure of relativistic electrons is limited to {approx}< 10% of the thermal electron pressure, with stricter limits for the more massive clusters, indicating that these electrons are likely not dynamically important in the central regions of clusters.

  3. Modeling of non-thermal plasma in flammable gas mixtures

    NASA Astrophysics Data System (ADS)

    Napartovich, A. P.; Kochetov, I. V.; Leonov, S. B.

    2008-07-01

    An idea of using plasma-assisted methods of fuel ignition is based on non-equilibrium generation of chemically active species that speed up the combustion process. It is believed that gain in energy consumed for combustion acceleration by plasmas is due to the non-equilibrium nature of discharge plasma, which allows radicals to be produced in an above-equilibrium amount. Evidently, the size of the effect is strongly dependent on the initial temperature, pressure, and composition of the mixture. Of particular interest is comparison between thermal ignition of a fuel-air mixture and non-thermal plasma initiation of the combustion. Mechanisms of thermal ignition in various fuel-air mixtures have been studied for years, and a number of different mechanisms are known providing an agreement with experiments at various conditions. The problem is -- how to conform thermal chemistry approach to essentially non-equilibrium plasma description. The electric discharge produces much above-equilibrium amounts of chemically active species: atoms, radicals and ions. The point is that despite excess concentrations of a number of species, total concentration of these species is far below concentrations of the initial gas mixture. Therefore, rate coefficients for reactions of these discharge produced species with other gas mixture components are well known quantities controlled by the translational temperature, which can be calculated from the energy balance equation taking into account numerous processes initiated by plasma. A numerical model was developed combining traditional approach of thermal combustion chemistry with advanced description of the plasma kinetics based on solution of electron Boltzmann equation. This approach allows us to describe self-consistently strongly non-equilibrium electric discharge in chemically unstable (ignited) gas. Equations of pseudo-one-dimensional gas dynamics were solved in parallel with a system of thermal chemistry equations, kinetic equations

  4. Thermal and Nonthermal Processes on Single Crystal Transition Metal Surfaces

    NASA Astrophysics Data System (ADS)

    Guo, Xingcai

    This dissertation contains three parts. Part I, "Fundamentals", provides concise description of concepts, detailed accounts of historic studies, and extensive reviews of current activities. Chapter 1 deals with thermal processes (adsorption and desorption), and Chapter 2 with nonthermal processes induced by electrons and by photons. Part II, "Experimental" (Chapter 3), describes the ultrahigh vacuum apparatus, surface science techniques, and procedures for single crystal preparation and gas exposure. Part III, "Results", is a collection of ten selected publications in refereed journals. Each chapter is self-contained. Thermal desorption of CO from Pd(111) (Chapter 4) has been studied by temperature programmed desorption. It is demonstrated that the effective desorption kinetic parameters extracted from desorption spectra are correlated with the adlayer structures and dependent on the sizes of ordered domains--a nonequilibrium effect. Site exchange of CO (Chapter 5) and site retention of O_2 (Chapter 6) on Pt(112) during thermal desorption are observed with isotope labeled adsorption on specific sites--steps or terraces. The adsorption and desorption kinetics of O _2 are compared on Pt(111) and Pt(112) surfaces (Chapter 7). The mechanisms of adsorption and the effect of well-defined defects are elucidated. O_2 adsorbed on Pd(111) is studied with thermal activation (Chapter 8), electron impact (Chapter 9), and photon irradiation (Chapter 10 -12). Various thermal processes are delineated with isotopic mixing experiments. Electron-induced conversion, dissociation, and desorption processes are observed. Cross sections (10^{-17} cm^2 ) and their electron energy dependences (0-500 eV) are measured. A resonance-enhanced desorption of atomic oxygen from Pd(111) is found at ~10 eV. Photon-induced conversion, dissociation, and desorption processes are observed. Cross sections (10^ {-19} cm^2) and photon energy dependence (1.4-5.4 eV) are extracted. Possible mechanisms are

  5. Refined scenario of standard Big Bang nucleosynthesis allowing for nonthermal nuclear reactions in the primordial plasma

    SciTech Connect

    Voronchev, Victor T.; Nakao, Yasuyuki; Nakamura, Makoto; Tsukida, Kazuki

    2012-11-12

    The standard scenario of big bang nucleosynthesis (BBN) is generalized to take into account nonthermal nuclear reactions in the primordial plasma. These reactions are naturally triggered in the BBN epoch by fast particles generated in various exoergic processes. It is found that, although such particles can appreciably enhance the rates of some individual reactions, their influence on the whole process of element production is not significant. The nonthermal corrections to element abundances are obtained to be 0.1% ({sup 3}H), -0.03% ({sup 7}Li), and 0.34 %-0.63% (CNO group).

  6. On the operation of machines powered by quantum non-thermal baths

    NASA Astrophysics Data System (ADS)

    Niedenzu, Wolfgang; Gelbwaser-Klimovsky, David; Kofman, Abraham G.; Kurizki, Gershon

    2016-08-01

    Diverse models of engines energised by quantum-coherent, hence non-thermal, baths allow the engine efficiency to transgress the standard thermodynamic Carnot bound. These transgressions call for an elucidation of the underlying mechanisms. Here we show that non-thermal baths may impart not only heat, but also mechanical work to a machine. The Carnot bound is inapplicable to such a hybrid machine. Intriguingly, it may exhibit dual action, concurrently as engine and refrigerator, with up to 100% efficiency. We conclude that even though a machine powered by a quantum bath may exhibit an unconventional performance, it still abides by the traditional principles of thermodynamics.

  7. DNA damage and mitochondria dysfunction in cell apoptosis induced by nonthermal air plasma

    SciTech Connect

    Kim, G. J.; Lee, J. K.; Kim, W.; Kim, K. T.

    2010-01-11

    Nonthermal plasma is known to induce animal cell death but the mechanism is not yet clear. Here, cellular and biochemical regulation of cell apoptosis is demonstrated for plasma treated cells. Surface type nonthermal air plasma triggered apoptosis of B16F10 mouse melanoma cancer cells causing DNA damage and mitochondria dysfunction. Plasma treatment activated caspase-3, apoptosis executioner. The plasma treated cells also accumulated gamma-H2A.X, marker for DNA double strand breaks, and p53 tumor suppressor gene as a response to DNA damage. Interestingly, cytochrome C was released from mitochondria and its membrane potential was changed significantly.

  8. Reactive oxygen species controllable non-thermal helium plasmas for evaluation of plasmid DNA strand breaks

    NASA Astrophysics Data System (ADS)

    Young Kim, Jae; Lee, Dong-Hoon; Ballato, John; Cao, Weiguo; Kim, Sung-O.

    2012-11-01

    Non-thermal, oxygen-rich helium plasmas were investigated to achieve an enhanced reactive oxygen species concentration at low voltage driving conditions. A non-thermal plasma device was fabricated based on a theta-shaped tube, and its potential was investigated for use in topological alteration of plasmid DNA. The optical emission spectra of the plasma showed that the oxygen flow affected the plasma properties, even though an oxygen plasma was not produced. The plasmid DNA strand breaks became more significant with the addition of oxygen flow to the helium in a single hollow, theta-shaped tube with other experimental conditions being unchanged.

  9. Shock wave in magnetized dusty plasmas with dust charging and nonthermal ion effects

    SciTech Connect

    Zhang Liping; Xue Jukui

    2005-04-15

    The effects of the external magnetized field, nonadiabatic dust charge fluctuation, and nonthermally distributed ions on three-dimensional dust acoustic shock wave in dusty plasmas have been investigated. By using the reductive perturbation method, a Korteweg-de Vries (KdV) Burger equation governing the dust acoustic shock wave is derived. The results of numerical integrations of KdV Burger equation show that the external magnetized field, nonthermally distributed ions, and nonadiabatic dust charge fluctuation have strong influence on the shock structures.

  10. Compressive and rarefactive dressed solitons in plasma with nonthermal electrons and positrons

    NASA Astrophysics Data System (ADS)

    Abdelwahed, H. G.; El-Shewy, E. K.; Zahran, M. A.; Elwakil, S. A.

    2016-02-01

    The study of dressed solitary ion waves in a collisionless unmagnetized plasma composed warm fluid of ion, nonthermal distributed positrons and electrons are discussed. Concerning nonlinear ion acoustic waves, a reductive perturbation method is applied to obtain the KdV equation in terms of first order potential. Our results exemplify that, if soliton amplitude enlarged, the shape of the wave sidetrack from KdV equation. In order to improve the soliton shape, the perturbed KdV equation is suggest. In particular, the effects of nonthermal positrons and ionic temperature on the electrostatic dressed rarefactive and compressive soliton structures are discussed.

  11. Electrostatic solitary wave and double layer in a plasma with heavy ions and nonthermally distributed electrons

    SciTech Connect

    Choi, C.-R.; Min, K.-W.; Woo, M.-H.; Ryu, C.-M.

    2010-09-15

    The existence condition for bump and dip type, as well as double layer (DL), solutions of electrostatic solitary waves (ESWs) in a nonthermal electron plasma with heavy ions is investigated by a pseudopotential method. It is found that the nonthermality of electrons determines the existence of the DL solution and that the amplitude of ESWs is enhanced by the density of heavy ions. When the heavy ion density is beyond a certain critical value, ESWs and DLs cannot exist. It is also found that both the lower and upper critical Mach numbers are reduced by the presence of heavy ions.

  12. Nonlinear features of electrostatic waves in a plasma with nonthermal-Tsallis distributed electrons

    NASA Astrophysics Data System (ADS)

    Dutta, Debjit; Sahu, Biswajit

    2016-06-01

    Linear and nonlinear properties of electrostatic waves are investigated in an unmagnetized multicomponent plasma system consisting of cold and hot electrons obeying nonthermal-Tsallis distribution and warm ions using the Sagdeev pseudopotential technique. It is found that such a plasma supports soliton, supersoliton, and double layer structures. Also, the present plasma system supports the coexistence of arbitrary amplitude compressive and rarefactive solitons in a certain region of parameter space. Furthermore, numerical results reveal that the nonthermal-Tsallis distribution of electrons may affect the spatial profiles as well as the nature of the electrostatic nonlinear structures.

  13. DNA damage and mitochondria dysfunction in cell apoptosis induced by nonthermal air plasma

    NASA Astrophysics Data System (ADS)

    Kim, G. J.; Kim, W.; Kim, K. T.; Lee, J. K.

    2010-01-01

    Nonthermal plasma is known to induce animal cell death but the mechanism is not yet clear. Here, cellular and biochemical regulation of cell apoptosis is demonstrated for plasma treated cells. Surface type nonthermal air plasma triggered apoptosis of B16F10 mouse melanoma cancer cells causing DNA damage and mitochondria dysfunction. Plasma treatment activated caspase-3, apoptosis executioner. The plasma treated cells also accumulated gamma-H2A.X, marker for DNA double strand breaks, and p53 tumor suppressor gene as a response to DNA damage. Interestingly, cytochrome C was released from mitochondria and its membrane potential was changed significantly.

  14. Instability of nonplanar modulated dust acoustic wave packets in a strongly coupled nonthermal dusty plasma

    SciTech Connect

    El-Labany, S. K. Zedan, N. A.; El-Taibany, W. F. E-mail: eltaibany@du.edu.eg

    2015-07-15

    Cylindrical and spherical amplitude modulations of dust acoustic (DA) solitary wave envelopes in a strongly coupled dusty plasma containing nonthermal distributed ions are studied. Employing a reductive perturbation technique, a modified nonlinear Schrödinger equation including the geometrical effect is derived. The influences of nonthermal ions, polarization force, and the geometries on the modulational instability conditions are analyzed and the possible rogue wave structures are discussed in detail. It is found that the spherical DA waves are more structurally stable to perturbations than the cylindrical ones. Possible applications of these theoretical findings are briefly discussed.

  15. Multiband tissue classification for ultrasonic transmission tomography using spectral profile detection

    NASA Astrophysics Data System (ADS)

    Jeong, Jeong-Won; Kim, Tae-Seong; Shin, Dae-Chul; Do, Synho; Marmarelis, Vasilis Z.

    2004-04-01

    Recently it was shown that soft tissue can be differentiated with spectral unmixing and detection methods that utilize multi-band information obtained from a High-Resolution Ultrasonic Transmission Tomography (HUTT) system. In this study, we focus on tissue differentiation using the spectral target detection method based on Constrained Energy Minimization (CEM). We have developed a new tissue differentiation method called "CEM filter bank". Statistical inference on the output of each CEM filter of a filter bank is used to make a decision based on the maximum statistical significance rather than the magnitude of each CEM filter output. We validate this method through 3-D inter/intra-phantom soft tissue classification where target profiles obtained from an arbitrary single slice are used for differentiation in multiple tomographic slices. Also spectral coherence between target and object profiles of an identical tissue at different slices and phantoms is evaluated by conventional cross-correlation analysis. The performance of the proposed classifier is assessed using Receiver Operating Characteristic (ROC) analysis. Finally we apply our method to classify tiny structures inside a beef kidney such as Styrofoam balls (~1mm), chicken tissue (~5mm), and vessel-duct structures.

  16. A SiGe BiCMOS multi-band tuner for mobile TV applications

    NASA Astrophysics Data System (ADS)

    Xueqing, Hu; Zheng, Gong; Jinxin, Zhao; Lei, Wang; Peng, Yu; Yin, Shi

    2012-04-01

    This paper presents the circuit design and measured performance of a multi-band tuner for mobile TV applications. The tuner RFIC is composed of a wideband front-end, an analog baseband, a full integrated fractional-N synthesizer and an I2C digital interface. To meet the stringent adjacent channel rejection (ACR) requirements of mobile TV standards while keeping low power consumption and low cost, direct conversion architecture with a local AGC scheme is adopted in this design. Eighth-order elliptic active-RC filters with large stop band attenuation and a sharp transition band are chosen as the channel select filter to further improve the ACR preference. The chip is fabricated in a 0.35-μm SiGe BiCMOS technology and occupies a silicon area of 5.5 mm2. It draws 50 mA current from a 3.0 V power supply. In CMMB application, it achieves a sensitivity of -97 dBm with 1/2 coding QPSK signal input and over 40 dB ACR.

  17. Monitoring the pollution of river Ganga by tanneries using the multiband ground truth radiometer

    NASA Astrophysics Data System (ADS)

    Tripathi, Nitin Kumar; Venkobachar, C.; Singh, Ramesh Kumar; Singh, Shiv Pal

    The feasibility of utilising the multiband ground truth radiometer (MGTR) for monitoring the pollution of the river Ganga by tanneries at Kanpur, India is explored. Parameters targeted in the study were Secchi depth (a measure of turbidity), turbidity, tannin concentration and chemical oxygen demand (COD). MGTR offers reflectance in 11 bands within the spectral range of 0.45 to 0.90 μm. The reflectance data has been utilised to develop empirical relationships with Secchi depth, turbidity and tannin concentration. The spectral reflectance data does not directly indicate the measure of the COD. However, an empirical relationship between tannin concentration and COD has been established which allows an indirect measurement of the COD. The conventional environmental engineering laboratory approach for determination of the above parameters is time consuming, expensive and slow. This results in serious constraints in monitoring pollution parameters at frequent intervals for a large number of sampling points. The outcome of the study shows the viability of MGTR as a means of quick, repetitive and handy remote sensing for monitoring pollution caused by tanneries in narrow surface streams.

  18. ICI mitigation in concurrent multi-band receiver due to the phase noise and IQ imbalance

    NASA Astrophysics Data System (ADS)

    Lee, Hui-Kyu; Ryu, Heung-Gyoon

    2012-06-01

    For the next generation long-term evolution (LTE) advanced mobile communication system, 100 MHz bandwidth and 1 Gbit/s data speed are needed. However, there is not enough and wide vacant frequency band. Therefore, spectrum aggregation method has been studied to extend available frequency bands. Frequency synthesiser and power amplifier of transceiver should cover this wide bandwidth. The phase noise and In-phase and quadrature (IQ) imbalance would increase, which would be a serious problem in this transceiver. Also, signal-to-noise ratio becomes degraded because of nonlinearity and the quantisation noises of the Analog-to-digital conversion (ADC) in the receiver. Uplink of LTE-advanced uses Aggregated DFT-spread (NxDFT-S) orthogonal frequency division multiplexing (OFDM) signals. Since the effect of the phase noise and IQ imbalance are more serious in the multi-band Discrete Fourier transform (DFT)-spreading OFDM system, we like to analyse the effect of inter-carrier interference in frequency domain of receiver and the degradation of bit error rate (BER) performance. Also, by the channel response in frequency domain of the uplink system, we separate phase noise and IQ imbalance effect. Finally, we like to propose a compensation method that estimates the channel exactly and removes IQ imbalance and phase noise. Simulation result shows that the proposed method achieves the 2 dB performance gain of BER = 10-4.

  19. Multi-band Polarimetry of the Lunar Surface. I. Global Properties

    NASA Astrophysics Data System (ADS)

    Jeong, Minsup; Kim, Sungsoo S.; Garrick-Bethell, Ian; Park, So-Myoung; Sim, Chae Kyung; Jin, Ho; Min, Kyoung Wook; Choi, Young-Jun

    2015-11-01

    We have conducted multi-band (U, B, V, R, and I) polarimetric observations of the whole near-side of the Moon for phase angles between 22° and 121° with a spatial resolution of 1.1 km. A median grain size (< d> ) map of the near-side regolith of the Moon has been constructed using our polarimetry. We find that < d> is a monotonically increasing function of selenographic latitude β < d> at | β | ≃ 60^\\circ is estimated to be up to 40% larger than that at the equator. At the same latitude, < d> is larger in the maria than in the highlands, confirming the initial findings of Shkuratov et al. The former is thought to be a result of reduced space weathering effects at high latitudes, where the flux of weathering agents such as micrometeoroids and solar wind particles is smaller. The latter probably indicates that the regolith material in the maria is more resistant to comminution by space weathering than is the material in the highlands. We also find that three photometric or polarimetric maturity indices—optical maturity, < d> , and the color ratio of parallel-component polarization ({C}\\parallel )—have different sensitivities on young small craters and rays of large craters. We present possible causes of these different sensitivities.

  20. Compact multi-band fluorescent microscope with an electrically tunable lens for autofocusing

    PubMed Central

    Wang, Zhaojun; Lei, Ming; Yao, Baoli; Cai, Yanan; Liang, Yansheng; Yang, Yanlong; Yang, Xibin; Li, Hui; Xiong, Daxi

    2015-01-01

    Autofocusing is a routine technique in redressing focus drift that occurs in time-lapse microscopic image acquisition. To date, most automatic microscopes are designed on the distance detection scheme to fulfill the autofocusing operation, which may suffer from the low contrast of the reflected signal due to the refractive index mismatch at the water/glass interface. To achieve high autofocusing speed with minimal motion artifacts, we developed a compact multi-band fluorescent microscope with an electrically tunable lens (ETL) device for autofocusing. A modified searching algorithm based on equidistant scanning and curve fitting is proposed, which no longer requires a single-peak focus curve and then efficiently restrains the impact of external disturbance. This technique enables us to achieve an autofocusing time of down to 170 ms and the reproductivity of over 97%. The imaging head of the microscope has dimensions of 12 cm × 12 cm × 6 cm. This portable instrument can easily fit inside standard incubators for real-time imaging of living specimens. PMID:26601001

  1. Achieving a multi-band metamaterial perfect absorber via a hexagonal ring dielectric resonator

    NASA Astrophysics Data System (ADS)

    Li, Li-Yang; Wang, Jun; Du, Hong-Liang; Wang, Jia-Fu; Qu, Shao-Bo

    2015-06-01

    A multi-band absorber composed of high-permittivity hexagonal ring dielectric resonators and a metallic ground plate is designed in the microwave band. Near-unity absorptions around 9.785 GHz, 11.525 GHz, and 12.37 GHz are observed for this metamaterial absorber. The dielectric hexagonal ring resonator is made of microwave ceramics with high permittivity and low loss. The mechanism for the near-unity absorption is investigated via the dielectric resonator theory. It is found that the absorption results from electric and magnetic resonances where enhanced electromagnetic fields are excited inside the dielectric resonator. In addition, the resonance modes of the hexagonal resonator are similar to those of standard rectangle resonators and can be used for analyzing hexagonal absorbers. Our work provides a new research method as well as a solid foundation for designing and analyzing dielectric metamaterial absorbers with complex shapes. Project supported by the National Natural Science Foundation of China (Grant Nos. 61331005, 11204378, 11274389, 11304393, and 61302023), the Aviation Science Foundation of China (Grant Nos. 20132796018 and 20123196015), the Natural Science Foundation for Post-Doctoral Scientists of China (Grant Nos. 2013M532131 and 2013M532221), the Natural Science Foundation of Shaanxi Province, China (Grant No. 2013JM6005), and the Special Funds for Authors of Annual Excellent Doctoral Degree Dissertations of China (Grant No. 201242).

  2. Multiband optical-NIR variability of blazars on diverse time-scales

    NASA Astrophysics Data System (ADS)

    Agarwal, Aditi; Gupta, Alok C.; Bachev, R.; Strigachev, A.; Semkov, E.; Wiita, Paul J.; Böttcher, M.; Boeva, S.; Gaur, H.; Gu, M. F.; Peneva, S.; Ibryamov, S.; Pandey, U. S.

    2015-08-01

    To search for optical variability on a wide range of time-scales, we have carried out photometric monitoring of two flat spectrum radio quasars, 3C 454.3 and 3C 279, plus one BL Lac, S5 0716+714, all of which have been exhibiting remarkably high activity and pronounced variability at all wavelengths. CCD magnitudes in B, V, R, and I passbands were determined for ˜7000 new optical observations from 114 nights made during 2011-2014, with an average length of ˜4 h each, at seven optical telescopes: four in Bulgaria, one in Greece, and two in India. We measured multiband optical flux and colour variations on diverse time-scales. Discrete correlation functions were computed among B, V, R, and I observations, to search for any time delays. We found weak correlations in some cases with no significant time lags. The structure function method was used to estimate any characteristic time-scales of variability. We also investigated the spectral energy distribution of the three blazars using B, V, R, I, J, and K passband data. We found that the sources almost always follow a bluer-when-brighter trend. We discuss possible physical causes of the observed spectral variability.

  3. Multiband infrared plume simulator for HWIL testing of the tactical FLIR pod modification

    NASA Astrophysics Data System (ADS)

    Thomas, Matthew C.; Pritchett, Donald G.; Ellis, Thomas A.

    1998-07-01

    A multi-band infrared plume simulator (MIPS) system capable of projecting light from three spectrally separate, dynamic infrared (IR) sources has been developed by the Defense Special Weapons Agency (DSWA) and Mission Research Corporation (MRC). The purpose of this system is to provide long-wave IR (LWIR) movies of bomb explosions for a forward looking IR (FLIR), and high power pulses of medium-wave IR (MWIR) light to simulate the radiance intensity from the plumes in two bands for a non-imaging radiometer. The FLIR and two-color radiometer are detectors in the new Tactical FLIR Pod Modification (TFPM). The LWIR movies are generated with a DSWA Nuclear Optical Dynamic Display System (NODDS) 512 X 512 suspended membrane emitter array. The MWIR plume signatures are generated with two lead-salt laser diodes. The emitter array supplies the 8 micrometer to 12 micrometer, time-varying images with peak apparent temperatures of about 350 K. The two laser diodes, one emitting at 4.6 micrometer and the other at 3.8 micrometer, supply the higher power signals to simulate greater than 1000 K plumes for the two-color radiometer. The design of the MIPS is based on the design of the TFPM and the TFPM is based on the results from the Dipole Pride test series, so this paper will review the Dipole Pride results and the TFPM specifications in addition to examining the operation of the MIPS.

  4. Al/SiOx/Al single and multiband metamaterial absorbers for terahertz sensor applications

    NASA Astrophysics Data System (ADS)

    Kearney, Brian; Alves, Fabio; Grbovic, Dragoslav; Karunasiri, Gamani

    2013-01-01

    To increase the sensitivity of uncooled thermal sensors in the terahertz (THz) spectral range (1 to 10 THz), we investigated thin metamaterial layers exhibiting resonant absorption in this region. These metamaterial films are comprised of periodic arrays of aluminum (Al) squares and an Al ground plane separated by a thin silicon-rich silicon oxide (SiOx) dielectric film. These standard MEMS materials are also suitable for fabrication of bi-material and microbolometer thermal sensors. Using SiOx instead of SiO2 reduced the residual stress of the metamaterial film. Finite element simulations were performed to establish the design criteria for very thin films with high absorption and spectral tunability. Single-band structures with varying SiOx thicknesses, square size, and periodicity were fabricated and found to absorb nearly 100% at the designed frequencies between three and eight THz. Multiband absorbing structures were fabricated with two or three distinct peaks or a single-broad absorption band. Experimental results indicate that is possible to design very efficient thin THz absorbing films to match specific applications.

  5. The image registration of multi-band images by geometrical optics

    NASA Astrophysics Data System (ADS)

    Yan, Yung-Jhe; Chiang, Hou-Chi; Tsai, Yu-Hsiang; Huang, Ting-Wei; Mang, Ou-Yang

    2015-09-01

    The image fusion is combination of two or more images into one image. The fusion of multi-band spectral images has been in many applications, such as thermal system, remote sensing, medical treatment, etc. Images are taken with the different imaging sensors. If the sensors take images through the different optical paths in the same time, it will be in the different positions. The task of the image registration will be more difficult. Because the images are in the different field of views (F.O.V.), the different resolutions and the different view angles. It is important to build the relationship of the viewpoints in one image to the other image. In this paper, we focus on the problem of image registration for two non-pinhole sensors. The affine transformation between the 2-D image and the 3-D real world can be derived from the geometrical optics of the sensors. In the other word, the geometrical affine transformation function of two images are derived from the intrinsic and extrinsic parameters of two sensors. According to the affine transformation function, the overlap of the F.O.V. in two images can be calculated and resample two images in the same resolution. Finally, we construct the image registration model by the mapping function. It merges images for different imaging sensors. And, imaging sensors absorb different wavebands of electromagnetic spectrum at the different position in the same time.

  6. Soft tissue differentiation using multiband signatures of high resolution ultrasonic transmission tomography.

    PubMed

    Jeong, Jeong-Won; Kim, Tae-Seong; Shin, Dae C; Do, Synho; Singh, Manbir; Marmarelis, Vasilis Z

    2005-03-01

    In this paper, we are interested in soft tissue differentiation by multiband images obtained from the High-Resolution Ultrasonic Transmission Tomography (HUTT) system using a spectral target detection method based on constrained energy minimization (CEM). We have developed a new tissue differentiation method (called "CEM filter bank") consisting of multiple CEM filters specially designed for detecting multiple types of tissues. Statistical inference on the output of the CEM filter bank is used to make a decision based on the maximum statistical significance rather than the magnitude of each CEM filter output. We test and validate this method through three-dimensional interphantom/intraphantom soft tissue classification where target profiles obtained from an arbitrary single slice are used for differentiation over multiple other tomographic slices. The performance of the proposed classifier is assessed using receiver operating characteristic analysis. We also apply our method to classify tiny structures inside a bovine kidney and sheep kidneys. Using the proposed method we can detect physical objects and biological tissues such as styrofoam balls, chicken tissue, calyces, and vessel-duct successfully. PMID:15754990

  7. Beyond the standard model of Ginzburg-Landau theory: multiband superconductors

    NASA Astrophysics Data System (ADS)

    Wilson, Brendan J.; Das, Mukunda P.

    2014-08-01

    The recently discovered multiband superconductors have created a new class of novel superconductors. In these materials multiple superconducting gaps arise due to the formation of Cooper pairs on different sheets of the Fermi surfaces. An important feature of these superconductors is the interband couplings, which not only change the individual gap properties, but also create new collective modes. Here we investigate the effect of the interband couplings in the Ginzburg-Landau theory. We produce a general τ(2n + 1)/2 expansion (τ = 1 - T/Tc) and show that this expansion has unexpected behaviour for n ⩾ 2. This point emphasises the weaker validity of the GL theory for lower temperatures and gives credence to the existence of hidden criticality near the critical temperature of the uncoupled subdominant band. We apply this theory to a range of material parameters fitted to experimental measurements and find that for some cases the theory performs very well at all temperatures, but for other materials the range of applicability can be very limited.

  8. Metallic Ferromagnetism Supported by a Single Band in a Multi-band Hubbard Model

    NASA Astrophysics Data System (ADS)

    Tanaka, Akinori; Tasaki, Hal

    2016-06-01

    We construct a multi-band Hubbard model on the lattice obtained by "decorating" a closely packed d-dimensional lattice {M} (such as the triangular lattice) where d≥ 2. We take the limits in which the Coulomb interaction and the band gap become infinitely large. Then there remains only a single band with finite energy, on which electrons are supported. Let the electron number be N_{e}=|{M}|-N_{h}, where |{M}| corresponds to the electron number which makes the lowest (finite energy) band half-filled, and N_{h} is the number of "holes". It is expected that the model exhibits metallic ferromagnetism if N_{h}/|{M}| is nonvanishing but sufficiently small. We prove that the ground states exhibit saturated ferromagnetism if N_{h}≤ ( {const.})|{M}|^{2/(d+2)}, and exhibit (not necessarily saturated) ferromagnetism if N_{h}≤ ( {const.})|{M}|^{(d+1)/(d+2)}. This may be regarded as a rigorous example of metallic ferromagnetism provided that the system size |{M}| is not too large.

  9. Aerosol and Surface Parameter Retrievals for a Multi-Angle, Multiband Spectrometer

    NASA Technical Reports Server (NTRS)

    Broderick, Daniel

    2012-01-01

    This software retrieves the surface and atmosphere parameters of multi-angle, multiband spectra. The synthetic spectra are generated by applying the modified Rahman-Pinty-Verstraete Bidirectional Reflectance Distribution Function (BRDF) model, and a single-scattering dominated atmosphere model to surface reflectance data from Multiangle Imaging SpectroRadiometer (MISR). The aerosol physical model uses a single scattering approximation using Rayleigh scattering molecules, and Henyey-Greenstein aerosols. The surface and atmosphere parameters of the models are retrieved using the Lavenberg-Marquardt algorithm. The software can retrieve the surface and atmosphere parameters with two different scales. The surface parameters are retrieved pixel-by-pixel while the atmosphere parameters are retrieved for a group of pixels where the same atmosphere model parameters are applied. This two-scale approach allows one to select the natural scale of the atmosphere properties relative to surface properties. The software also takes advantage of an intelligent initial condition given by the solution of the neighbor pixels.

  10. Exposure assessment in front of a multi-band base station antenna.

    PubMed

    Kos, Bor; Valič, Blaž; Kotnik, Tadej; Gajšek, Peter

    2011-04-01

    This study investigates occupational exposure to electromagnetic fields in front of a multi-band base station antenna for mobile communications at 900, 1800, and 2100 MHz. Finite-difference time-domain method was used to first validate the antenna model against measurement results published in the literature and then investigate the specific absorption rate (SAR) in two heterogeneous, anatomically correct human models (Virtual Family male and female) at distances from 10 to 1000 mm. Special attention was given to simultaneous exposure to fields of three different frequencies, their interaction and the additivity of SAR resulting from each frequency. The results show that the highest frequency--2100 MHz--results in the highest spatial-peak SAR averaged over 10 g of tissue, while the whole-body SAR is similar at all three frequencies. At distances > 200 mm from the antenna, the whole-body SAR is a more limiting factor for compliance to exposure guidelines, while at shorter distances the spatial-peak SAR may be more limiting. For the evaluation of combined exposure, a simple summation of spatial-peak SAR maxima at each frequency gives a good estimation for combined exposure, which was also found to depend on the distribution of transmitting power between the different frequency bands. PMID:21365667

  11. Optimization of data coils in a multiband wireless link for neuroprosthetic implantable devices.

    PubMed

    Uei-Ming Jow; Ghovanloo, M

    2010-10-01

    We have presented the design methodology along with detailed simulation and measurement results for optimizing a multiband transcutaneous wireless link for high-performance implantable neuroprosthetic devices. We have utilized three individual carrier signals and coil/antenna pairs for power transmission, forward data transmission from outside into the body, and back telemetry in the opposite direction. Power is transmitted at 13.56 MHz through a pair of printed spiral coils (PSCs) facing each other. Two different designs have been evaluated for forward data coils, both of which help to minimize power carrier interference in the received data carrier. One is a pair of perpendicular coils that are wound across the diameter of the power PSCs. The other design is a pair of planar figure-8 coils that are in the same plane as the power PSCs. We have compared the robustness of each design against horizontal misalignments and rotations in different directions. Simulation and measurements are also conducted on a miniature spiral antenna, designed to operate with impulse-radio ultra-wideband (IR-UWB) circuitry for back telemetry. PMID:21918679

  12. Compact multi-band fluorescent microscope with an electrically tunable lens for autofocusing.

    PubMed

    Wang, Zhaojun; Lei, Ming; Yao, Baoli; Cai, Yanan; Liang, Yansheng; Yang, Yanlong; Yang, Xibin; Li, Hui; Xiong, Daxi

    2015-11-01

    Autofocusing is a routine technique in redressing focus drift that occurs in time-lapse microscopic image acquisition. To date, most automatic microscopes are designed on the distance detection scheme to fulfill the autofocusing operation, which may suffer from the low contrast of the reflected signal due to the refractive index mismatch at the water/glass interface. To achieve high autofocusing speed with minimal motion artifacts, we developed a compact multi-band fluorescent microscope with an electrically tunable lens (ETL) device for autofocusing. A modified searching algorithm based on equidistant scanning and curve fitting is proposed, which no longer requires a single-peak focus curve and then efficiently restrains the impact of external disturbance. This technique enables us to achieve an autofocusing time of down to 170 ms and the reproductivity of over 97%. The imaging head of the microscope has dimensions of 12 cm × 12 cm × 6 cm. This portable instrument can easily fit inside standard incubators for real-time imaging of living specimens. PMID:26601001

  13. Multi-mode multi-band power amplifier module with high low-power efficiency

    NASA Astrophysics Data System (ADS)

    Xuguang, Zhang; Jie, Jin

    2015-10-01

    Increasingly, mobile communications standards require high power efficiency and low currents in the low power mode. This paper proposes a fully-integrated multi-mode and multi-band power amplifier module (PAM) to meet these requirements. A dual-path PAM is designed for high-power mode (HPM), medium-power mode (MPM), and low-power mode (LPM) operations without any series switches for different mode selection. Good performance and significant current saving can be achieved by using an optimized load impedance design for each power mode. The PAM is tapeout with the InGaP/GaAs heterojunction bipolar transistor (HBT) process and the 0.18-μm complementary metal-oxide semiconductor (CMOS) process. The test results show that the PAM achieves a very low quiescent current of 3 mA in LPM. Meanwhile, across the 1.7-2.0 GHz frequency, the PAM performs well. In HPM, the output power is 28 dBm with at least 39.4% PAE and -40 dBc adjacent channel leakage ratio 1 (ACLR1). In MPM, the output power is 17 dBm, with at least 21.3% PAE and -43 dBc ACLR1. In LPM, the output power is 8 dBm, with at least 18.2% PAE and -40 dBc ACLR1. Project supported by the National Natural Science Foundation of China (No. 61201244).

  14. Independent polarization and multi-band THz absorber base on Jerusalem cross

    NASA Astrophysics Data System (ADS)

    Arezoomand, Afsaneh Saee; Zarrabi, Ferdows B.; Heydari, Samaneh; Gandji, Navid P.

    2015-10-01

    In this paper, we present the design and simulation of a single and multi-band perfect metamaterial absorber (MA) in the THz region base on Jerusalem cross (JC) and metamaterial load in unit cells. The structures consist of dual metallic layers for allowing near-perfect absorption with absorption peak of more than 99%. In this novel design, four-different shape of Jerusalem cross is presented and by adding L, U and W shape loaded to first structure, we tried to achieve a dual-band absorber. In addition, by good implementation of these loaded, we are able to control the absorption resonance at second resonance at 0.9, 0.7 and 0.85 THz respectively. In the other hand, we achieved a semi stable designing at first resonance between 0.53 and 0.58 THz. The proposed absorber has broadband polarization angle. The surface current modeled and proved the broadband polarization angle at prototype MA. The LC resonance of the metamaterial for Jerusalem cross and modified structures are extracting from equivalent circuit. As a result, proposed MA is useful for THz medical imaging and communication systems and the dual-band absorber has applications in many scientific and technological areas.

  15. An effect of the ionospheric Alfvén resonator on multiband Pc1 pulsations

    NASA Astrophysics Data System (ADS)

    Prikner, K.; Mursula, K.; Kangas, J.; Kerttula, R.; Feygin, F.

    2004-02-01

    . On 2 December 1999, the magnetometer stations in northern Finland registered structured Pc1 activity simultaneously in three distinct frequency bands. Using simultaneous EISCAT radar measurements of the high-latitude ionosphere, we have studied the ionospheric resonator properties during this multiband Pc1 event. The frequencies of the three structured Pc1 bands were found to closely correspond to the second, third and fourth harmonic of the calculated fundamental frequency of the ionospheric Alfvén resonator (IAR). In addition, those frequencies of the three pearl bands that were closest to the exact IAR harmonics were found to have the strongest intensities. The results demonstrate that the resonator can have an important role on ground-based Pc1 activity over a notably large frequency range, favoring transmission of waves with frequencies close to the resonator's eigenfrequencies. Since the frequencies of all three bands correspond to the maximum rather than the minimum of the transmission coefficient, the traditional bouncing wave packet model needs to be revised.

  16. Multiband optical variability of three TeV blazars on diverse time-scales

    NASA Astrophysics Data System (ADS)

    Gupta, Alok C.; Agarwal, A.; Bhagwan, J.; Strigachev, A.; Bachev, R.; Semkov, E.; Gaur, H.; Damljanovic, G.; Vince, O.; Wiita, Paul J.

    2016-05-01

    We present our optical photometric observations of three TeV blazars, PKS 1510-089, PG 1553+113, and Mrk 501, taken using two telescopes in India, one in Bulgaria, one in Greece, and one in Serbia during 2012-2014. These observations covered a total of 95 nights with a total of 202 B filter frames, 247 images in V band, 817 in R band while 229 images were taken in the I filter. This work is focused on multiband flux and colour variability studies of these blazars on diverse time-scales which are useful in understanding the emission mechanisms. We studied the variability characteristics of above three blazars and found all to be active over our entire observational campaigns. We also searched for any correlation between the brightness of the sources and their colour indices. During the times of variability, no significant evidence for the sources to display spectral changes correlated with magnitude was found on time-scales of a few months. We briefly discuss the possible physical mechanisms most likely responsible for the observed flux variability.

  17. Independent peer review panel report on the integrated nonthermal treatment systems study and the comparison of integrated thermal and integrated nonthermal treatment systems for mixed low level waste

    SciTech Connect

    1996-08-01

    The US Department of Energy`s (DOE) Office of Environmental Management (EM) Office of Science and Technology (OST) has conducted studies of integrated thermal treatment systems and integrated nonthermal treatment systems (INTS) for treating contact handled, alpha and non-alpha mixed low level radioactive waste (MLLW). The MLLW in the DOE complex consists of a wide variety of organic and inorganic solids and liquids contaminated with radioactive substances. Treatment systems are needed to destroy organic material and stabilize residues prior to land disposal. In May 1996 the Deputy Assistant Secretary for OST appointed an Independent Peer Review Panel to: (1) review and comment on the INTS Study; (2) make recommendations on the most promising thermal and nonthermal treatment systems; (3) make recommendations on research and development necessary to prove the performance of nonthermal and thermal technologies; and (4) review and comment on the preliminary draft of the ITTS/INTS Comparison Report. This report presents the primary conclusions and recommendations based on the review of the INTS study and the comparison report. System selection, overviews, comparisons, cost estimations and sensitivity analyses, and recommended R and D engineering needs are then described and discussed.

  18. Generation of ordinary mode electromagnetic radiation near the upper hybrid frequency in the magnetosphere

    NASA Technical Reports Server (NTRS)

    Ashour-Abdalla, M.; Okuda, H.

    1984-01-01

    It is shown by means of plasma numerical simulations that long-wavelength ordinary mode electromagnetic radiation can be generated from short-wavelength electrostatic waves near the upper hybrid resonance frequency in an inhomogeneous plasma. A possible relation of this process to nonthermal continuum radiation in the magnetosphere is discussed.

  19. Non-thermal Plasma Activates Human Keratinocytes by Stimulation of Antioxidant and Phase II Pathways

    PubMed Central

    Schmidt, Anke; Dietrich, Stephan; Steuer, Anna; Weltmann, Klaus-Dieter; von Woedtke, Thomas; Masur, Kai; Wende, Kristian

    2015-01-01

    Non-thermal atmospheric pressure plasma provides a novel therapeutic opportunity to control redox-based processes, e.g. wound healing, cancer, and inflammatory diseases. By spatial and time-resolved delivery of reactive oxygen and nitrogen species, it allows stimulation or inhibition of cellular processes in biological systems. Our data show that both gene and protein expression is highly affected by non-thermal plasma. Nuclear factor erythroid-related factor 2 (NRF2) and phase II enzyme pathway components were found to act as key controllers orchestrating the cellular response in keratinocytes. Additionally, glutathione metabolism, which is a marker for NRF2-related signaling events, was affected. Among the most robustly increased genes and proteins, heme oxygenase 1, NADPH-quinone oxidoreductase 1, and growth factors were found. The roles of NRF2 targets, investigated by siRNA silencing, revealed that NRF2 acts as an important switch for sensing oxidative stress events. Moreover, the influence of non-thermal plasma on the NRF2 pathway prepares cells against exogenic noxae and increases their resilience against oxidative species. Via paracrine mechanisms, distant cells benefit from cell-cell communication. The finding that non-thermal plasma triggers hormesis-like processes in keratinocytes facilitates the understanding of plasma-tissue interaction and its clinical application. PMID:25589789

  20. Food irradiation and nonthermal food processing: an overview for food science professionals

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Irradiation is a nonthermal process that has been shown to inactivate human pathogens from meats, seafood and produce. Irradiation treatment at 1.0 kGy can reduce the surface populations of E. coli O157:H7 on leafy vegetables by 4 logs (99.99%), without significantly impacting the product’s visual a...

  1. Mediation of the solar wind termination shock by non-thermal ions.

    PubMed

    Decker, R B; Krimigis, S M; Roelof, E C; Hill, M E; Armstrong, T P; Gloeckler, G; Hamilton, D C; Lanzerotti, L J

    2008-07-01

    Broad regions on both sides of the solar wind termination shock are populated by high intensities of non-thermal ions and electrons. The pre-shock particles in the solar wind have been measured by the spacecraft Voyager 1 (refs 1-5) and Voyager 2 (refs 3, 6). The post-shock particles in the heliosheath have also been measured by Voyager 1 (refs 3-5). It was not clear, however, what effect these particles might have on the physics of the shock transition until Voyager 2 crossed the shock on 31 August-1 September 2007 (refs 7-9). Unlike Voyager 1, Voyager 2 is making plasma measurements. Data from the plasma and magnetic field instruments on Voyager 2 indicate that non-thermal ion distributions probably have key roles in mediating dynamical processes at the termination shock and in the heliosheath. Here we report that intensities of low-energy ions measured by Voyager 2 produce non-thermal partial ion pressures in the heliosheath that are comparable to (or exceed) both the thermal plasma pressures and the scalar magnetic field pressures. We conclude that these ions are the >0.028 MeV portion of the non-thermal ion distribution that determines the termination shock structure and the acceleration of which extracts a large fraction of bulk-flow kinetic energy from the incident solar wind. PMID:18596801

  2. Non-thermal emission from the interaction of extragalactic jets with stars

    NASA Astrophysics Data System (ADS)

    Vieyro, Florencia; Bosch-Ramon, Valenti; Torres-Albà, Núria

    2016-07-01

    The central regions of galaxies are rich environments, often full with stars and medium inhomogeneities. For galaxies hosting active galactic nuclei, the interaction of a relativistic jet with these objects can lead to the formation of shocks, where particles can be accelerated up to relativistic energies. Recent numerical simulations show that the effective surface of the shock induced by the obstacle is higher than the obstacle section, increasing the available non-thermal energy. In this work, we analyze the non-thermal processes in these shocks. First, we make a detailed characterization of the stellar population in the central region of the galaxy, taking into account the evolution of stars with different masses. This allows us to obtain good estimates of the non-thermal energy. Then, we study the transport of relativistic electron accelerated in the shocks, and compute the gamma-ray emission. The interaction of relativistic jets with ambient objects, such as stars and clouds, can contribute significantly to the non-thermal emission from these sources.

  3. AN OUTLOOK OF NONTHERMAL PROCESSING TECHNOLOGIES AS FOOD SAFETY INTERVENTION STRATEGIES

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Foods should provide sensorial satisfaction and nutrition to people. Yet, foodborne pathogens cause significant illness and lose of life to human kind every year. A processing intervention step may be necessary prior to the consumption to ensure the safety of foods. Nonthermal processing technologi...

  4. A Study of Nonthermal X-Ray and Radio Emission from the O Star 9 Sgr

    NASA Technical Reports Server (NTRS)

    Waldron, Wayne L.; Corcoran, Michael F.; Drake, Stephen A.

    1999-01-01

    The observed X-ray and highly variable nonthermal radio emission from OB stars has eluded explanation for more than 18 years. The most favorable model of X-ray production in these stars (shocks) predicts both nonthermal radio and X-ray emission. The nonthermal X-ray emission should occur above 2 keV and the variability of this X-ray component should also be comparable to the observed radio variability. To test this scenario, we proposed an ASC/VLA monitoring program to observe the OB star, 9 Sgr, a well known nonthermal, variable radio source and a strong X-ray source. We requested 625 ks ASCA observations with a temporal spacing of approximately 4 days which corresponds to the time required for a density disturbance to propagate to the 6 cm radio free-free photosphere. The X-ray observations were coordinated with 5 multi-wavelength VLA observations. These observations represent the first systematic attempt to investigate the relationship between the X-ray and radio emission in OB stars.

  5. Experimental evidence of nonthermal acceleration of relativistic electrons by an intensive laser pulse

    SciTech Connect

    Kuramitsu, Y.; Sakawa, Y.; Takeda, K.; Tampo, M.; Takabe, H.; Nakanii, N.; Kondo, K.; Tsuji, K.; Kimura, K.; Fukumochi, S.; Kashihara, M.; Tanimoto, T.; Nakamura, H.; Ishikura, T.; Kodama, R.; Mima, K.; Tanaka, K. A.; Mori, Y.; Miura, E.; Kitagawa, Y.

    2011-02-15

    Nonthermal acceleration of relativistic electrons is investigated with an intensive laser pulse. An energy distribution function of energetic particles in the universe or cosmic rays is well represented by a power-law spectrum, therefore, nonthermal acceleration is essential to understand the origin of cosmic rays. A possible candidate for the origin of cosmic rays is wakefield acceleration at relativistic astrophysical perpendicular shocks. The wakefield is considered to be excited by large-amplitude precursor light waves in the upstream of the shocks. Substituting an intensive laser pulse for the large amplitude light waves, we performed a model experiment of the shock environments in a laboratory plasma. An intensive laser pulse was propagated in a plasma tube created by imploding a hollow polystyrene cylinder, as the large amplitude light waves propagated in the upstream plasma at an astrophysical shock. Nonthermal electrons were generated, and the energy distribution functions of the electrons have a power-law component with an index of {approx}2. We described the detailed procedures to obtain the nonthermal components from data obtained by an electron spectrometer.

  6. Energetic electron propagation in the decay phase of non-thermal flare emission

    SciTech Connect

    Huang, Jing; Yan, Yihua; Tsap, Yuri T.

    2014-06-01

    On the basis of the trap-plus-precipitation model, the peculiarities of non-thermal emission in the decay phase of solar flares have been considered. The calculation formulas for the escape rate of trapped electrons into the loss cone in terms of time profiles of hard X-ray (HXR) and microwave (MW) emission have been obtained. It has been found that the evolution of the spectral indices of non-thermal emission depend on the regimes of the pitch angle diffusion of trapped particles into the loss cone. The properties of non-thermal electrons related to the HXR and MW emission of the solar flare on 2004 November 3 are studied with Nobeyama Radioheliograph, Nobeyama Radio Polarimeters, RHESSI, and Geostationary Operational Environmental Satellite observations. The spectral indices of non-thermal electrons related to MW and HXR emission remained constant or decreased, while the MW escape rate as distinguished from that of the HXRs increased. This may be associated with different diffusion regimes of trapped electrons into the loss cone. New arguments in favor of an important role of the superstrong diffusion for high-energy electrons in flare coronal loops have been obtained.

  7. The role of non-thermal factors in the control of skin blood flow during exercise.

    PubMed

    Nielsen, B

    1986-01-01

    Arguments in favor of the importance of non-thermal factors in the control of skin circulation are presented. Such factors include exercise, posture, water and electrolyte balance, state of training, and acclimatization. The first three factors probably elicit their effects via high- and low-pressure baroreceptors, while the mechanisms involved for the remainder are unknown. PMID:3529655

  8. Experimental evidence of nonthermal acceleration of relativistic electrons by an intensive laser pulse.

    PubMed

    Kuramitsu, Y; Nakanii, N; Kondo, K; Sakawa, Y; Mori, Y; Miura, E; Tsuji, K; Kimura, K; Fukumochi, S; Kashihara, M; Tanimoto, T; Nakamura, H; Ishikura, T; Takeda, K; Tampo, M; Kodama, R; Kitagawa, Y; Mima, K; Tanaka, K A; Hoshino, M; Takabe, H

    2011-02-01

    Nonthermal acceleration of relativistic electrons is investigated with an intensive laser pulse. An energy distribution function of energetic particles in the universe or cosmic rays is well represented by a power-law spectrum, therefore, nonthermal acceleration is essential to understand the origin of cosmic rays. A possible candidate for the origin of cosmic rays is wakefield acceleration at relativistic astrophysical perpendicular shocks. The wakefield is considered to be excited by large-amplitude precursor light waves in the upstream of the shocks. Substituting an intensive laser pulse for the large amplitude light waves, we performed a model experiment of the shock environments in a laboratory plasma. An intensive laser pulse was propagated in a plasma tube created by imploding a hollow polystyrene cylinder, as the large amplitude light waves propagated in the upstream plasma at an astrophysical shock. Nonthermal electrons were generated, and the energy distribution functions of the electrons have a power-law component with an index of ~2. We described the detailed procedures to obtain the nonthermal components from data obtained by an electron spectrometer. PMID:21405912

  9. Irradiation as a non-thermal process for beverages, juices and fluid foods

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Irradiation is a nonthermal process that can effectively inactivate human pathogens in a variety of foods. A successful commercial application of this technology to fluid foods such as juices and beverages must balance the antimicrobial effects of the treatment with potential negative effects on sen...

  10. Nonthermal plasma system for extending shelf life of raw broiler breast fillets

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A nonthermal dielectric barrier discharge (DBD) plasma system was developed and enhanced to treat broiler breast fillets (BBF) in order to improve the microbial quality of the meat. The system consisted of a high-voltage source and two parallel, round-aluminum electrodes separated by three semi-rig...

  11. Non-thermal plasmas as gas-phase advanced oxidation processes

    SciTech Connect

    Rosocha, L.A.

    1997-08-01

    Non-thermal plasmas are useful for generating reactive species (free radicals) in a gas stream. Because radical attack reaction rate constants are very large for many chemical species, entrained pollutants are readily decomposed by radicals. Such plasmas can generate both oxidative and reductive radicals; therefore, they show promise for treating a wide variety of pollutants.

  12. Cold plasma - a non-thermal processing technology to inactivate human pathogens on foods

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cold plasma is a novel non-thermal food processing technology, suitable for application to fresh and fresh-cut fruits and vegetables. Reductions of 3-5 logs have been achieved against human pathogens such as Salmonella and E. coli O157:H7 on fresh produce and against phytopathogens and spoilage orga...

  13. TURBULENCE IN THE SUPERMODEL: MASS RECONSTRUCTION WITH NONTHERMAL PRESSURE FOR A1835

    SciTech Connect

    Fusco-Femiano, R.; Lapi, A.

    2013-07-10

    The total mass derived from X-ray emission is biased low in a large number of clusters when compared with the mass estimated via strong and weak lensing. Suzaku and Chandra observations out to the virial radius report in several relaxed clusters' steep temperature gradients that on assuming pure thermal hydrostatic equilibrium (HE) imply an unphysically decreasing mass profile. Moreover, the gas mass fraction appears to be inconsistent with the cosmic value measured from the cosmic microwave background. Such findings can be interpreted as evidence for an additional nonthermal pressure in the outskirts of these clusters. This nonthermal component may be due to turbulence stirred by residual bulk motions of extragalactic gas infalling into the cluster. Here, we present a SuperModel analysis of A1835 observed by Chandra out to the virial radius. The SuperModel formalism can include in the equilibrium a nonthermal component whose level and distribution are derived imposing that the gas mass fraction (f{sub gas}) equals the cosmic value at the virial radius. Including such a nonthermal component, we reconstruct from X-rays an increasing mass profile consistent with the HE also in the cluster outskirts and in agreement at the virial boundary with the weak-lensing value. The increasing f{sub gas} profile confirms that the baryons are not missing but located at the cluster outskirts.

  14. FIRST REPORT ON NON-THERMAL PLASMA REACTOR SCALING CRITERIA AND OPTIMIZATION MODELS

    EPA Science Inventory

    The purpose of SERDP project CP-1038 is to evaluate and develop non-thermal plasma (NTP) reactor technology for DoD air emissions control applications. The primary focus is on oxides of nitrogen (NOx) and a secondary focus on hazardous air pollutants (HAPs), especially volatile o...

  15. Behavioral modeling and digital compensation of nonlinearity in DFB lasers for multi-band directly modulated radio-over-fiber systems

    NASA Astrophysics Data System (ADS)

    Li, Jianqiang; Yin, Chunjing; Chen, Hao; Yin, Feifei; Dai, Yitang; Xu, Kun

    2014-11-01

    The envisioned C-RAN concept in wireless communication sector replies on distributed antenna systems (DAS) which consist of a central unit (CU), multiple remote antenna units (RAUs) and the fronthaul links between them. As the legacy and emerging wireless communication standards will coexist for a long time, the fronthaul links are preferred to carry multi-band multi-standard wireless signals. Directly-modulated radio-over-fiber (ROF) links can serve as a lowcost option to make fronthaul connections conveying multi-band wireless signals. However, directly-modulated radioover- fiber (ROF) systems often suffer from inherent nonlinearities from directly-modulated lasers. Unlike ROF systems working at the single-band mode, the modulation nonlinearities in multi-band ROF systems can result in both in-band and cross-band nonlinear distortions. In order to address this issue, we have recently investigated the multi-band nonlinear behavior of directly-modulated DFB lasers based on multi-dimensional memory polynomial model. Based on this model, an efficient multi-dimensional baseband digital predistortion technique was developed and experimentally demonstrated for linearization of multi-band directly-modulated ROF systems.

  16. The effects of non-thermal plasmas on selected mammalian cells

    NASA Astrophysics Data System (ADS)

    Leduc, Mathieu

    Non-thermal plasma surface modifications have become indispensable processing steps in various industry and research sectors. Applications range from semiconductor processing to biotechnology and recently, plasma medicine. Non-thermal plasma sources have the advantage that a number of electron-driven chemical reactions can be produced while maintaining the gas (heavy species) temperature low, thus enabling the treatment of temperature-sensitive surfaces such as polymers, tissues and live cells. In the fields of biology and medicine, non-thermal plasmas have been primarily used for the deposition or modification of biocompatible polymers and for sterilization. Recently, non-thermal plasmas have been used to treat tissues and cells. A new field of research has emerged, Plasma Medicine, which studies the effects of non-thermal plasmas on cells and tissues for clinical applications. The Atmospheric Pressure Glow Discharge torch (APGD-t), a non-thermal plasma source, built in our laboratory was used to study the effects of non-thermal plasmas on mammalian cells. In its first application, we indirectly used the APGD-t to deposit a plasma-polymer on a glass surface and studied its effects on cultured cells. It was shown that the cells grew preferentially on the plasma-polymer, and their proliferation rate increased. The second application of the APGD-t was to further investigate previous observations of cell permeabilization obtained by plasma treatments and to apply non-thermal plasmas to cell transfection. It was demonstrated that the APGD-t is able to locally transfect adherent cells. We estimated the diameter of the pores created to be below 10 nm and that the pores remain open for less than 5 seconds. However, while investigating the mechanisms involved in cell transfection we observed that the use of higher gas flows in the negative controls (using the APGD-t but with the plasma turned off) also resulted in cell transfection. To further study this phenomena, we

  17. Slightly thermal springs and non-thermal springs at Mount Shasta, California: Chemistry and recharge elevations

    USGS Publications Warehouse

    Nathenson, M.; Thompson, J.M.; White, L.D.

    2003-01-01

    Temperature measurements, isotopic contents, and dissolved constituents are presented for springs at Mount Shasta to understand slightly thermal springs in the Shasta Valley based on the characteristics of non-thermal springs. Non-thermal springs on Mount Shasta are generally cooler than mean annual air temperatures for their elevation. The specific conductance of non-thermal springs increases linearly with discharge temperature. Springs at higher and intermediate elevations on Mount Shasta have fairly limited circulation paths, whereas low-elevation springs have longer paths because of their higher-elevation recharge. Springs in the Shasta Valley are warmer than air temperatures for their elevation and contain significant amounts of chloride and sulfate, constituents often associated with volcanic hydrothermal systems. Data for the Shasta Valley springs generally define mixing trends for dissolved constituents and temperature. The isotopic composition of the Shasta Valley springs indicates that water fell as precipitation at a higher elevation than any of the non-thermal springs. It is possible that the Shasta Valley springs include a component of the outflow from a proposed 210??C hydrothermal system that boils to supply steam for the summit acid-sulfate spring. In order to categorize springs such as those in the Shasta Valley, we introduce the term slightly thermal springs for springs that do not meet the numerical criterion of 10??C above air temperature for thermal springs but have temperatures greater than non-thermal springs in the area and usually also have dissolved constituents normally found in thermal waters. ?? 2002 Elsevier Science B.V. All rights reserved.

  18. Slightly thermal springs and non-thermal springs at Mount Shasta, California: Chemistry and recharge elevations

    NASA Astrophysics Data System (ADS)

    Nathenson, M.; Thompson, J. M.; White, L. D.

    2003-02-01

    Temperature measurements, isotopic contents, and dissolved constituents are presented for springs at Mount Shasta to understand slightly thermal springs in the Shasta Valley based on the characteristics of non-thermal springs. Non-thermal springs on Mount Shasta are generally cooler than mean annual air temperatures for their elevation. The specific conductance of non-thermal springs increases linearly with discharge temperature. Springs at higher and intermediate elevations on Mount Shasta have fairly limited circulation paths, whereas low-elevation springs have longer paths because of their higher-elevation recharge. Springs in the Shasta Valley are warmer than air temperatures for their elevation and contain significant amounts of chloride and sulfate, constituents often associated with volcanic hydrothermal systems. Data for the Shasta Valley springs generally define mixing trends for dissolved constituents and temperature. The isotopic composition of the Shasta Valley springs indicates that water fell as precipitation at a higher elevation than any of the non-thermal springs. It is possible that the Shasta Valley springs include a component of the outflow from a proposed 210°C hydrothermal system that boils to supply steam for the summit acid-sulfate spring. In order to categorize springs such as those in the Shasta Valley, we introduce the term slightly thermal springs for springs that do not meet the numerical criterion of 10°C above air temperature for thermal springs but have temperatures greater than non-thermal springs in the area and usually also have dissolved constituents normally found in thermal waters.

  19. Multi-Zone Modeling of Nonthermal Radiation from Pulsar Wind Nebulae

    NASA Astrophysics Data System (ADS)

    Van Etten, Adam; Romani, R. W.

    2012-01-01

    Many pulsar wind nebulae (PWN) are spatially resolved in the radio, X-ray, and even very high energy (VHE) wavebands, and thereby provide an excellent laboratory to study not only pulsar winds and dynamics, but also shock processes, the ambient medium, magnetic feld evolution, and particle transport. Single-zone spectral energy distribution (SED) models have long been used to study the global properties of PWN, but to fully take advantage of high resolution data one must move beyond these simple models. I describe 3-D time-dependent PWN spectral energy distribution modeling, with particular emphasis on the spatial variations within the large and bright PWN associated with PSR J1826-1334, HESS J1825-137. Within this PWN, the gamma-ray spectral index is observed to soften with increasing distance from the pulsar, likely the result of cooling losses as electrons traverse the nebula. The large size and high nebular energy budget imply a relatively rapid initial pulsar spin period of 13±7 ms and an age of 40±9 kyr. The relative fluxes of each VHE zone can be explained by advective particle transport with a radially decreasing velocity profile with v(r) r(-0.5). The evolution of the cooling break requires an evolving magnetic field which also decreases radially from the pulsar, B(r,t) r(-0.7)Edot(t)(0.5). Detection of 10 TeV flux 80 pc from the pulsar requires rapid diffusion of high energy particles with κesc≈90(R/10 pc)2(E/100 TeV)(-1)year, contrary to the common assumption of toroidal magnetic fields with strong magnetic confinement. The model predicts a rather uniform Fermi LAT surface brightness out to 1 degree from the pulsar, in good agreement with the recently discovered LAT source centered 0.5 degree southwest of PSR J1826-1334 with extension 0.6±0.1 degree. The growing number of sources with spatially resolved X-ray and VHE measurements (e.g. Vela-X, HESS J1303-631) are prime targets for such multi-zone modeling.

  20. Measuring the beaming angle of GRB 030329 by fitting the rebrightenings in its multiband afterglow

    NASA Astrophysics Data System (ADS)

    Deng, Wei; Huang, Yong-Feng; Kong, Si-Wei

    2010-11-01

    Multiple rebrightenings have been observed in the multiband afterglow of GRB 030329. In particular, a marked and quick rebrightening occurred at about t ~ 1.2 × 105 s. Energy injection from late and slow shells seems to be the best interpretation for these rebrightenings. Usually it is assumed that the energy is injected into the whole external shock. However, in the case of GRB 030329, the rebrightenings are so quick that the usual consideration fails to give a satisfactory fit to the observed light curves. Actually, since these late/slow shells freely coast in the wake of the external shock, they should be cold and may not expand laterally. The energy injection then should only occur at the central region of the external shock. Considering this effect, we numerically re-fit the quick rebrightenings observed in GRB 030329. By doing this, we were able to derive the beaming angle of the energy injection process. Our result, with a relative residual of only 5% - 10% during the major rebrightening, is better than any previous modeling. The derived energy injection angle is about 0.035. We assume that these late shells are ejected by the central engine via the same mechanism as those early shells that produce the prompt gamma-ray burst. The main difference is that their velocities are much slower, so that they catch up with the external shock relatively late and are manifested as the observed quick rebrightenings. If this were true, then the derived energy injection angle can give a good measure of the beaming angle of the prompt γ-ray emission. Our study may hopefully provide a novel method to measure the beaming angle of gamma-ray bursts.

  1. Optical fabrication and metrology for a visible through thermal infrared multi-band imaging system

    SciTech Connect

    Magner, J.; Henson, T.

    1998-04-01

    The optical fabrication, metrology, and system wavefront testing of an off-axis three mirror anastigmatic telescope will be presented. The telescope is part of a multi-band imaging system which includes a single mechanically cooled focal plane with 15 spectral bands covering a wavelength range from 0.45 microns to 10.7 microns and an on board calibration subsystem. The imaging system is to be operated in a low earth orbit in a pushbroom scanning mode. The telescope has a 36 cm aperture, a 1.38 degree cross track by 1.82 degree along-track field of view (FOV), near diffraction limited performance in the visible, and strictly diffraction limited performance from 1.3 microns to 10.7 microns. The primary and the tertiary mirrors are general aspheres which have undergone 80% lightweighting. The secondary mirror is a hyperbola. The primary mirror was extremely difficult to fabricate and test due to its large departure from sphericity, fast f-number, and large off axis distance. The tertiary mirror has a small departure from sphericity and is only slightly off-axis, but it has a very fast f-number also. The surface wavefront measurements for the three mirrors after final figuring and lightweighting are 0.048 waves rms {at}0.6328 microns for the primary mirror and 0.025 waves rms {at}0.6328 microns for the secondary and tertiary mirrors. The telescope wavefront requirement at the center of the along-track FOV is 0.178 waves rms {at}0.6328 microns and at the edge of the along-track FOV is 0.677 waves rms {at} 0.6328 microns.

  2. Mass accretion rates from multiband photometry in the Carina Nebula: the case of Trumpler 14

    NASA Astrophysics Data System (ADS)

    Beccari, G.; De Marchi, G.; Panagia, N.; Valenti, E.; Carraro, G.; Romaniello, M.; Zoccali, M.; Weidner, C.

    2015-01-01

    Context. We present a study of the mass accretion rates of pre-main sequence (PMS) stars in the cluster Trumpler 14 (Tr 14) in the Carina Nebula. Using optical multiband photometry we were able to identify 356 PMS stars showing Hα excess emission with equivalent width EW(Hα) > 20 Å. We interpret this observational feature as an indication that these objects are still actively accreting gas from their circumstellar medium. From a comparison of the HR diagram with PMS evolutionary models we derive ages and masses of the PMS stars. We find that most of the PMS objects are younger than 10 Myr with a median age of ~3 Myr. Surprisingly, we also find that ~20% of the mass accreting objects are older than 10 Myr. For each PMS star in Trumpler 14 we determine the mass accretion rate (Ṁacc) and discuss its dependence on mass and age. We finally combine the optical photometry with near-IR observations to build the spectral energy distribution (SED) for each PMS star in Tr 14. The analysis of the SEDs suggests the presence of transitional discs in which a large amount of gas is still present and sustains accretion onto the PMS object at ages older than 10 Myr. Our results, discussed in light of recent recent discoveries with Herschel of transitional discs containing a massive gas component around the relatively old PMS stars TW Hydrae, 49 Ceti, and HD 95086, support a new scenario n which old and evolved debris discs still host a significant amount of gas. Aims: Methods: Results:

  3. Multiband Spitzer phase curves of three highly-irradiated hot Jupiters

    NASA Astrophysics Data System (ADS)

    Wong, Ian

    2016-01-01

    Recent improvements in the capabilities of space- and ground-based telescopes as well as data reduction techniques have enabled us to characterize the atmospheres of exoplanets in exquisite detail, revealing a diverse range of properties. Phase curve observations, which track the variation in the infrared brightness of a planet throughout its orbit, allow us to create a full longitudinal temperature profile of the planet. In conjunction with model-generated light curves, these data are invaluable for constraining fundamental properties of the atmosphere, including the efficiency of heat transport from the day side to the night side, the spatial distribution of clouds, and the presence of chemical gradients between the two hemispheres. A comparison of the day-night thermal flux differences for the 11 planets with previously-published phase curve observations suggests that the most highly-irradiated planets tend to have systematically less efficient day-night heat recirculation. To further study this trend, we have obtained multiband infrared phase curves for three additional highly-irradiated planets - WASP-14b, WASP-19b, and HAT-P-7b. By combining observations spanning multiple wavelengths, we are able to probe different depths in their atmospheres and to construct low-resolution day side and night side emission spectra, which can reveal differences in atmospheric composition between the day and night sides. These planets cover a wide range of orbital eccentricities and host star temperature. In addition, we supplement our analysis of HAT-P-7b with an optical Kepler phase curve. We compare the results of our analysis with a suite of atmospheric models to infer various properties of these atmospheres. We also place our results in the wider context of other planets with published thermal phase curves in order to assess the interplay between irradiation, atmospheric chemistry, and orbital characteristics in driving atmospheric dynamics.

  4. Interplay of charge density wave and multiband superconductivity in 2H-PdxTaSe2

    PubMed Central

    Bhoi, D.; Khim, S.; Nam, W.; Lee, B. S.; Kim, Chanhee; Jeon, B.-G.; Min, B. H.; Park, S.; Kim, Kee Hoon

    2016-01-01

    2H-TaSe2 has been one of unique transition metal dichalcogenides exhibiting several phase transitions due to a delicate balance among competing electronic ground states. An unusual metallic state at high-T is sequentially followed by an incommensurate charge density wave (ICDW) state at ≈122 K and a commensurate charge density wave (CCDW) state at ≈90 K, and superconductivity at TC ~ 0.14 K. Upon systematic intercalation of Pd ions into TaSe2, we find that CCDW order is destabilized more rapidly than ICDW to indicate a hidden quantum phase transition point at x ~ 0.09–0.10. Moreover, TC shows a dramatic enhancement up to 3.3 K at x = 0.08, ~24 times of TC in 2H-TaSe2, in proportional to the density of states N(EF). Investigations of upper critical fields Hc2 in single crystals reveal evidences of multiband superconductivity as temperature-dependent anisotropy factor γH = , quasi-linear increase of , and an upward, positive-curvature in near TC. Furthermore, analysis of temperature-dependent electronic specific heat corroborates the presence of multiple superconducting gaps. Based on above findings and electronic phase diagram vs x, we propose that the increase of N(EF) and effective electron-phonon coupling in the vicinity of CDW quantum phase transition should be a key to the large enhancement of TC in PdxTaSe2. PMID:27045426

  5. Model calculations of Raman responses for multiband iron-based superconductors

    NASA Astrophysics Data System (ADS)

    Sauer, Christoph

    In this thesis I compute Raman responses for a free electron band structure model based on ARPES measurements on multiband iron-based superconductors. First a constant and then a k-dependent superconducting gap is used. Applying an effective mass approximation leaves A 1g and B2 g as the only nonvanishing symmetry channels. In the latter only one band contributes and a square root singularity is observed for a constant gap. The k-dependent gap leads to a threshold- log-singularity structure. The unscreened A 1g channel shows the same features but all bands contribute and sum up. The screened single band A1g response vanishes for both gaps. Two band responses with the same constant gap are perfectly screened with identical Raman vertices, unscreened with opposite signs and equal mass ratios and partially screened in all other cases. With two different constant gaps the singularities are removed and a dome-like shape appears except for the vanishing case of equal vertices. The n-band response consists of a sum of two band terms normalized by all n bands and the singularities corresponding to all uniquely present gap values are removed. With the k-dependent gap the singularities are removed and a dome-like shape appears in all combinations of two band responses and in the response for all bands. The dome in the response for all bands shows a flat continuum in between a threshold and a sharp peak produced by the two band terms containing bands of opposite signs.

  6. Interplay of charge density wave and multiband superconductivity in 2H-PdxTaSe2.

    PubMed

    Bhoi, D; Khim, S; Nam, W; Lee, B S; Kim, Chanhee; Jeon, B-G; Min, B H; Park, S; Kim, Kee Hoon

    2016-01-01

    2H-TaSe2 has been one of unique transition metal dichalcogenides exhibiting several phase transitions due to a delicate balance among competing electronic ground states. An unusual metallic state at high-T is sequentially followed by an incommensurate charge density wave (ICDW) state at ≈122 K and a commensurate charge density wave (CCDW) state at ≈90 K, and superconductivity at TC ~ 0.14 K. Upon systematic intercalation of Pd ions into TaSe2, we find that CCDW order is destabilized more rapidly than ICDW to indicate a hidden quantum phase transition point at x ~ 0.09-0.10. Moreover, TC shows a dramatic enhancement up to 3.3 K at x = 0.08, ~24 times of TC in 2H-TaSe2, in proportional to the density of states N(EF). Investigations of upper critical fields Hc2 in single crystals reveal evidences of multiband superconductivity as temperature-dependent anisotropy factor γH = , quasi-linear increase of , and an upward, positive-curvature in near TC. Furthermore, analysis of temperature-dependent electronic specific heat corroborates the presence of multiple superconducting gaps. Based on above findings and electronic phase diagram vs x, we propose that the increase of N(EF) and effective electron-phonon coupling in the vicinity of CDW quantum phase transition should be a key to the large enhancement of TC in PdxTaSe2. PMID:27045426

  7. Long-term Multi-band Photometric Monitoring of Blazar S5 0716+714

    NASA Astrophysics Data System (ADS)

    Dai, Ben-zhong; Zeng, Wei; Jiang, Ze-jun; Fan, Zhong-hui; Hu, Wen; Zhang, Peng-fei; Yang, Qing-yun; Yan, Da-hai; Wang, Dan; Zhang, Li

    2015-06-01

    We present long-term optical multi-band photometric monitoring of blazar S5 0716+714, from 2004 January 11 to 2012 November 4, with high temporal resolution of approximately 15 minutes in the BVRI bands. The source was in an active state during the whole monitoring campaign, showing intraday variability in 11 of 72 days. The average magnitudes in each band were B = 14.398, V = 13.821, R = 13.255, and I = 12.885. The overall variability amplitudes were {Δ }B=1\\buildrel{{m}}\\over{.}834, {Δ }V=2\\buildrel{{m}}\\over{.}167, {Δ }R=2\\buildrel{{m}}\\over{.}148, and {Δ }I=1\\buildrel{{m}}\\over{.}912. The structure function showed that typical timescales for intraday variability were between approximately 2 and 7.5 hr. The intraday variability amplitudes were from a few percent to approximately 30%. We found typical variation rates of approximately 0.05 mag hr-1 in both the rising and falling phases, with a minimal variability timescale of 130 minutes. A 10 day period short-term variability was observed simultaneously in the BVRI bands. The discrete correlation function suggests that there is significant correlated variability between the B- and I-band light curves. However, no significant time lags were detected. The spectral behaviors in the different variability episodes were studied, and our observations show bluer-when-brighter behavior on long, short, and intraday timescales for the blazar S5 0716+714. The variability and relevant spectral trends can be explained by the shock-in-jet scenario.

  8. Vetting Kepler planet candidates in the sub-Jovian desert with multiband photometry

    NASA Astrophysics Data System (ADS)

    Colón, Knicole D.; Morehead, Robert C.; Ford, Eric B.

    2015-09-01

    We present new multiband transit photometry of three small (Rp ≲ 6 R⊕), short-period (P ≲ 6 d) Kepler planet candidates acquired with the Gran Telescopio Canarias. These observations supplement the results presented in Colón & Ford and Colón, Ford & Morehead, where we used multicolour transit photometry of five Kepler planet candidates to search for wavelength-dependent transit depths and either validate planet candidates or identify eclipsing binary false positives within our sample. In those previous studies, we provided evidence that three targets were false positives and two targets were planets. Here, we present observations that provide evidence supporting a planetary nature for Kepler Object of Interest (KOI) 439.01 and KOI 732.01, and we find that KOI 531.01, a 6 R⊕ planet candidate around an M dwarf, is likely a false positive. We also present a discussion of the purported `sub-Jovian desert' in the orbital period-planet radius plane, which cannot be easily explained by observational bias. Both KOI 439.01 and KOI 732.01 are likely planets located within the so-called desert and should be investigated with further follow-up observations. As only ˜30 of the ˜3600 currently active Kepler planet candidates are located within the sub-Jovian desert, it will be interesting to see if these candidates also survive the vetting process and fill in the gap in the period-radius plane. Confirming planets in this regime will be important for understanding planetary migration and evolution processes, and we urge additional follow-up observations of these planet candidates to confirm their nature.

  9. Multi-band, multi-epoch observations of the transiting warm Jupiter WASP-80b

    SciTech Connect

    Fukui, Akihiko; Kuroda, Daisuke; Kawashima, Yui; Ikoma, Masahiro; Kurosaki, Kenji; Narita, Norio; Nishiyama, Shogo; Takahashi, Yasuhiro H.; Nagayama, Shogo; Onitsuka, Masahiro; Baba, Haruka; Ryu, Tsuguru; Ita, Yoshifusa; Onozato, Hiroki; Hirano, Teruyuki; Kawauchi, Kiyoe; Hori, Yasunori; Nagayama, Takahiro; Tamura, Motohide; Kawai, Nobuyuki; and others

    2014-08-01

    WASP-80b is a warm Jupiter transiting a bright late-K/early-M dwarf, providing a good opportunity to extend the atmospheric study of hot Jupiters toward the lower temperature regime. We report multi-band, multi-epoch transit observations of WASP-80b by using three ground-based telescopes covering from optical (g', R{sub c}, and I{sub c} bands) to near-infrared (NIR; J, H, and K{sub s} bands) wavelengths. We observe 5 primary transits, each in 3 or 4 different bands simultaneously, obtaining 17 independent transit light curves. Combining them with results from previous works, we find that the observed transmission spectrum is largely consistent with both a solar abundance and thick cloud atmospheric models at a 1.7σ discrepancy level. On the other hand, we find a marginal spectral rise in the optical region compared to the NIR region at the 2.9σ level, which possibly indicates the existence of haze in the atmosphere. We simulate theoretical transmission spectra for a solar abundance but hazy atmosphere, finding that a model with equilibrium temperature of 600 K can explain the observed data well, having a discrepancy level of 1.0σ. We also search for transit timing variations, but find no timing excess larger than 50 s from a linear ephemeris. In addition, we conduct 43 day long photometric monitoring of the host star in the optical bands, finding no significant variation in the stellar brightness. Combined with the fact that no spot-crossing event is observed in the five transits, our results confirm previous findings that the host star appears quiet for spot activities, despite the indications of strong chromospheric activities.

  10. A NEW MULTI-BAND RADIAL VELOCITY TECHNIQUE FOR DETECTING EXOPLANETS AROUND ACTIVE STARS

    SciTech Connect

    Ma Bo; Ge Jian E-mail: jge@astrto.ufl.edu

    2012-05-10

    The radial velocity (RV) technique is one of the most efficient ways of detecting exoplanets. However, large RV jitters induced by starspots on an active star can inhibit detection of any exoplanet present or even lead to a false positive detection. This paper presents a new multi-band RV technique capable of substantially reducing starspot-induced RV jitters from stellar RV measurements to allow efficient and accurate extraction of RV signals caused by exoplanets. It takes full advantage of the correlation of RV jitters at different spectral bands and the independence of exoplanet signals at the corresponding bands. Simulations with a single-spot model and a multi-spot model have been conducted to investigate the RV jitter reduction capability of this method. The results show that this method can reduce the RV jitter amplitude by at least an order of magnitude, allowing detection of weaker exoplanet signals without significantly increasing RV observation time and cadence. This method can greatly reduce the observation time required to detect Earth-like planets around solar type stars with {approx}0.1 m s{sup -1} long term Doppler precision if spot-induced jitter is the dominant astrophysical noise source for RV measurements. This method can work efficiently for RV jitter removal if: (1) all the spots on a target star have approximately the same temperature during RV observations; (2) the RV jitter amplitude changes with wavelength, i.e., the RV jitter amplitude ratio, {alpha}, between two different spectral bands is not close to one; (3) the spot-induced RV jitter dominates the RV measurement error.

  11. Multi-band algorithms for the estimation of chlorophyll concentration in the Chesapeake Bay

    NASA Astrophysics Data System (ADS)

    Gilerson, Alexander; Ondrusek, Michael; Tzortziou, Maria; Foster, Robert; El-Habashi, Ahmed; Tiwari, Surya Prakash; Ahmed, Sam

    2015-10-01

    Standard blue-green ratio algorithms do not usually work well in turbid productive waters because of the contamination of the blue and green bands by CDOM absorption and scattering by non-algal particles. One of the alternative approaches is based on the two- or three band ratio algorithms in the red/NIR part of the spectrum, which require 665, 708, 753 nm bands (or similar) and which work well in various waters all over the world. The critical 708 nm band for these algorithms is not available on MODIS and VIIRS sensors, which limits applications of this approach. We report on another approach where a combination of the 745nm band with blue-green-red bands was the basis for the new algorithms. A multi-band algorithm which includes ratios Rrs(488)/Rrs(551)and Rrs(671)/Rrs(745) and two band algorithm based on Rrs671/Rrs745 ratio were developed with the main focus on the Chesapeake Bay (USA) waters. These algorithms were tested on the specially developed synthetic datasets, well representing the main relationships between water parameters in the Bay taken from the NASA NOMAD database and available literature, on the field data collected by our group during a 2013 campaign in the Bay, as well as NASA SeaBASS data from the other group and on matchups between satellite imagery and water parameters measured by the Chesapeake Bay program. Our results demonstrate that the coefficient of determination can be as high as R2 > 0.90 for the new algorithms in comparison with R2 = 0.6 for the standard OC3V algorithm on the same field dataset. Substantial improvement was also achieved by applying a similar approach (inclusion of Rrs(667)/Rrs(753) ratio) for MODIS matchups. Results for VIIRS are not yet conclusive.

  12. Interplay of charge density wave and multiband superconductivity in 2H-PdxTaSe2

    NASA Astrophysics Data System (ADS)

    Bhoi, D.; Khim, S.; Nam, W.; Lee, B. S.; Kim, Chanhee; Jeon, B.-G.; Min, B. H.; Park, S.; Kim, Kee Hoon

    2016-04-01

    2H-TaSe2 has been one of unique transition metal dichalcogenides exhibiting several phase transitions due to a delicate balance among competing electronic ground states. An unusual metallic state at high-T is sequentially followed by an incommensurate charge density wave (ICDW) state at ≈122 K and a commensurate charge density wave (CCDW) state at ≈90 K, and superconductivity at TC ~ 0.14 K. Upon systematic intercalation of Pd ions into TaSe2, we find that CCDW order is destabilized more rapidly than ICDW to indicate a hidden quantum phase transition point at x ~ 0.09–0.10. Moreover, TC shows a dramatic enhancement up to 3.3 K at x = 0.08, ~24 times of TC in 2H-TaSe2, in proportional to the density of states N(EF). Investigations of upper critical fields Hc2 in single crystals reveal evidences of multiband superconductivity as temperature-dependent anisotropy factor γH = , quasi-linear increase of , and an upward, positive-curvature in near TC. Furthermore, analysis of temperature-dependent electronic specific heat corroborates the presence of multiple superconducting gaps. Based on above findings and electronic phase diagram vs x, we propose that the increase of N(EF) and effective electron-phonon coupling in the vicinity of CDW quantum phase transition should be a key to the large enhancement of TC in PdxTaSe2.

  13. Analysis of multi-band pyrometry for emissivity and temperature measurements of gray surfaces at ambient temperature

    NASA Astrophysics Data System (ADS)

    Araújo, António

    2016-05-01

    A multi-band pyrometry model is developed to evaluate the potential of measuring temperature and emissivity of assumably gray target surfaces at 300 K. Twelve wavelength bands between 2 and 60 μm are selected to define the spectral characteristics of the pyrometers. The pyrometers are surrounded by an enclosure with known background temperature. Multi-band pyrometry modeling results in an overdetermined system of equations, in which the solution for temperature and emissivity is obtained through an optimization procedure that minimizes the sum of the squared residuals of each system equation. The Monte Carlo technique is applied to estimate the uncertainties of temperature and emissivity, resulting from the propagation of the uncertainties of the pyrometers. Maximum reduction in temperature uncertainty is obtained from dual-band to tri-band systems, a small reduction is obtained from tri-band to quad-band, with a negligible reduction above quad-band systems (a reduction between 6.5% and 12.9% is obtained from dual-band to quad-band systems). However, increasing the number of bands does not always reduce uncertainty, and uncertainty reduction depends on the specific band arrangement, indicating the importance of choosing the most appropriate multi-band spectral arrangement if uncertainty is to be reduced. A reduction in emissivity uncertainty is achieved when the number of spectral bands is increased (a reduction between 6.3% and 12.1% is obtained from dual-band to penta-band systems). Besides, emissivity uncertainty increases for pyrometers with high wavelength spectral arrangements. Temperature and emissivity uncertainties are strongly dependent on the difference between target and background temperatures: uncertainties are low when the background temperature is far from the target temperature, tending to very high values as the background temperature approaches the target temperature.

  14. A Multi-Band Analytical Algorithm for Deriving Absorption and Backscattering Coefficients from Remote-Sensing Reflectance of Optically Deep Waters

    NASA Technical Reports Server (NTRS)

    Lee, Zhong-Ping; Carder, Kendall L.

    2001-01-01

    A multi-band analytical (MBA) algorithm is developed to retrieve absorption and backscattering coefficients for optically deep waters, which can be applied to data from past and current satellite sensors, as well as data from hyperspectral sensors. This MBA algorithm applies a remote-sensing reflectance model derived from the Radiative Transfer Equation, and values of absorption and backscattering coefficients are analytically calculated from values of remote-sensing reflectance. There are only limited empirical relationships involved in the algorithm, which implies that this MBA algorithm could be applied to a wide dynamic range of waters. Applying the algorithm to a simulated non-"Case 1" data set, which has no relation to the development of the algorithm, the percentage error for the total absorption coefficient at 440 nm a (sub 440) is approximately 12% for a range of 0.012 - 2.1 per meter (approximately 6% for a (sub 440) less than approximately 0.3 per meter), while a traditional band-ratio approach returns a percentage error of approximately 30%. Applying it to a field data set ranging from 0.025 to 2.0 per meter, the result for a (sub 440) is very close to that using a full spectrum optimization technique (9.6% difference). Compared to the optimization approach, the MBA algorithm cuts the computation time dramatically with only a small sacrifice in accuracy, making it suitable for processing large data sets such as satellite images. Significant improvements over empirical algorithms have also been achieved in retrieving the optical properties of optically deep waters.

  15. Dust acoustic solitons in a charge varying dusty plasma in the presence of ion nonthermality and background nonextensivity

    SciTech Connect

    Benzekka, Moufida; Tribeche, Mouloud

    2013-08-15

    Dust acoustic (DA) solitons are addressed in a charge varying dusty plasma in the presence of ion nonthermality and background nonextensivity. A physically meaningful nonthermal nonextensive ion distribution is outlined. The correct non-Maxwellian ion charging current is derived based on the orbit-limited motion theory. Under grain-current balance, the variable dust charge is expressed in terms of the Lambert function. It is found that nonthermality and its nonextensive nature may act concurrently and influence the restoring force and hence the soliton profile. Due to the flexibility provided by the nonextensive parameter, we think that our model should provide a better fit of the space observations.

  16. Unrepeatered field transmission of 2 Tbit/s multi-banded coherent WDM over 124 km of installed SMF.

    PubMed

    Frascella, Paola; Mac Suibhne, Naoise; Gunning, Fatima C Garcia; Ibrahim, Selwan K; Gunning, Paul; Ellis, Andrew D

    2010-11-22

    In this paper we report field transmission of a 2 Tbit/s multi-banded Coherent WDM signal over BT Ireland's installed SMF, using EDFA amplification only, with mixed Ethernet (with FEC) and PRBS payloads. To the best of our knowledge, the results obtained represent the highest total capacity transmitted over installed SMF with orthogonal subcarriers. BERs below 10(-5) and no frame-loss were recorded for all 49 subcarriers. Extended BER measurements over several hours showed fluctuations that can be attributed to PMD and to dynamic effects associated with clock instabilities. PMID:21164822

  17. Energetic secondary electrons and the nonthermal galactic radio background - A probe of the magnetic field in interstellar clouds

    NASA Technical Reports Server (NTRS)

    Marscher, A. P.; Brown, R. L.

    1978-01-01

    A previous analysis of the manifestations of charged-pion-decay secondary electrons in interstellar cloud material is extended to include those contributions to the Galactic radio and soft gamma-ray backgrounds that are directly attributable to energetic secondaries. The equilibrium distribution of secondary electrons in dense interstellar clouds is calculated, synchrotron emissivity from isolated interstellar clouds is examined, and it is shown how the value of the magnetic field in these clouds may be determined by observing the radio emission in their directions. The contribution that such clouds make to the integrated radio background is evaluated, and the Galactic distribution of bremsstrahlung gamma rays that arise from interactions of secondary electrons with thermal material in dense clouds is computed. The results indicate that a magnetic field of no more than 80 microgauss is characteristic of dense clouds and that the integrated synchrotron radiation from secondary electrons in interstellar clouds will contribute a significant fraction of the nonthermal brightness along the Galactic equator even if the mean cloud field is as low as 35 microgauss.

  18. EDITORIAL: Non-thermal plasma-assisted fuel conversion for green chemistry Non-thermal plasma-assisted fuel conversion for green chemistry

    NASA Astrophysics Data System (ADS)

    Nozaki, Tomohiro; Gutsol, Alexander

    2011-07-01

    This special issue is based on the symposium on Non-thermal Plasma Assisted Fuel Conversion for Green Chemistry, a part of the 240th ACS National Meeting & Exposition held in Boston, MA, USA, 22-26 August 2010. Historically, the Division of Fuel Chemistry of the American Chemical Society (ACS) has featured three plasma-related symposia since 2000, and has launched special issues in Catalysis Today on three occasions: 'Catalyst Preparation using Plasma Technologies', Fall Meeting, Washington DC, USA, 2000. Special issue in Catalysis Today 72 (3-4) with 12 peer-reviewed articles. 'Plasma Technology and Catalysis', Spring Meeting, New Orleans, LA, USA, 2003. Special issue in Catalysis Today 89 (1-2) with more than 30 peer-reviewed articles. 'Utilization of Greenhouse Gases II' (partly focused on plasma-related technologies), Spring Meeting, Anaheim, CA, USA, 2004. Special issue in Catalysis Today 98 (4) with 25 peer-reviewed articles. This time, selected presentations are published in this Journal of Physics D: Applied Physics special issue. An industrial material and energy conversion technology platform is established on thermochemical processes including various catalytic reactions. Existing industry-scale technology is already well established; nevertheless, further improvement in energy efficiency and material saving has been continuously demanded. Drastic reduction of CO2 emission is also drawing keen attention with increasing recognition of energy and environmental issues. Green chemistry is a rapidly growing research field, and frequently highlights renewable bioenergy, bioprocesses, solar photocatalysis of water splitting, and regeneration of CO2 into useful chemicals. We would also like to emphasize 'plasma catalysis' of hydrocarbon resources as an important part of the innovative next-generation green technologies. The peculiarity of non-thermal plasma is that it can generate reactive species almost independently of reaction temperature. Plasma

  19. Numerical study of electronic structure under uniform magnetic field and quantized Hall conductance for multi-band tight-binding models

    NASA Astrophysics Data System (ADS)

    Arai, Masao; Hatsugai, Yasuhiro

    2011-12-01

    The electronic structure of periodic lattice under uniform magnetic field was studied numerically for multi-band tight-binding models with non-orthogonal basis sets. When magnetic translational symmetry is fully taken into account, computational time can be greatly reduced. Quantized Hall conductance was evaluated by robust multi-band formulation of Chern number. We found that calculated quantized Hall conductance coincides with the semi-classical results. Discontinuous jumps of Hall conductance occur at van-Hove singularities and correspond to mod q ambiguity of the Diophantine equation of Chern number.

  20. Quantum radiation of Maxwell’s electromagnetic field in nonstationary Kerr-de Sitter black hole

    NASA Astrophysics Data System (ADS)

    Ibungochouba Singh, T.; Ablu Meitei, I.; Yugindro Singh, K.

    2016-03-01

    Quantum radiation properties of nonstationary Kerr-de Sitter (KdS) black hole is investigated using the method of generalized tortoise coordinate transformation. The locations of horizons and the temperature of the thermal radiation as well as the maximum energy of the nonthermal radiation are derived. It is found that the surface gravity and the Hawking temperature depend on both time and different angles. An extra coupling effect is obtained in the thermal radiation spectrum of Maxwell’s electromagnetic field equations which is absent in the thermal radiation spectrum of scalar particles. Further, the chemical potential derived from the thermal radiation spectrum of scalar particle has been found to be equal to the highest energy of the negative energy state of the scalar particle in the nonthermal radiation for KdS black hole. It is also shown that the generalized tortoise coordinate transformation produces a constant term in the expression of the surface gravity and Hawking temperature.

  1. Effects of nonthermal ions and polarization force on dust-acoustic waves in a density-varying dusty plasma.

    PubMed

    Asaduzzaman, M; Mamun, A A

    2012-07-01

    A rigorous theoretical investigation has been made of the effects of nonthermal ions and polarization force (which arises due to the dust density inhomogeneity) on the propagation of dust-acoustic (DA) waves in a density-varying unmagnetized dusty plasma (consisting of nonthermal ions, Maxwellian electrons, and negatively charged mobile dust) by the normal mode analysis. It has been shown that the dispersion properties of the DA waves are significantly modified by the presence of nonthermal ions and polarization force. It has been also found that the phase speed of the DA waves, as well as the dust density perturbation, increases (decreases) with the increase of nonthermal ions (polarization force), and that the potential associated with the DA waves decreases with the increase of the equilibrium dust number density. The implications of our results in the specific situation of space environments (dust-ion plasma situation) are also briefly discussed. PMID:23005552

  2. Detecteur multibandes libs a base de reseaux holographiques epais: Conception optomecanique et gestion de l'innovation

    NASA Astrophysics Data System (ADS)

    Gagnon, Daniel

    Detection of sulfur by optical emission spectroscopy generally presents difficulties because the strongest lines are in the vacuum ultraviolet and therefore are readily absorbed by oxygen molecules in air. A novel concept for a low cost and efficient system to detect sulfur using near infrared lines by Laser-Induced Breakdown Spectroscopy is proposed in this thesis. The concept proposes to use customized thick holographic gratings, also referred as Volume Bragg Grating, for spectral filtering of the plasma light, and built-in custom electronics that amplify and integrate photodiodes output signals. In this work, the optomechanical design, manufacturing and trials of a multiband sensor's prototype is reviewed. Preliminary results has been presented at NASLIBS 2011 and showed a limit of detection comparable to that of a conventional high-end system. An article describing the concept and results has been published in a special issue of the Applied Optics journal. To turn this newly patented concept into commercial success, the management of the innovation has been performed by proposing strategic and tactic alliances for commercialisation purposes applied to strategic business positioning structured along the 3 axis Technology -- Product -- Market. Open innovation is here acting as the paradigm to efficiently reach the market. Discussion relative to strategic and tactic alliance is actually taking place for deployment of the LIBS multiband sensor in the mining industry.

  3. Multiband d -p model and self-doping in the electronic structure of Ba2IrO4

    NASA Astrophysics Data System (ADS)

    Rościszewski, Krzysztof; Oleś, Andrzej M.

    2016-02-01

    We introduce and investigate the multiband d -p model describing a IrO4 layer (such as realized in Ba2IrO4 ) where all 34 orbitals per unit cell are partly occupied, i.e., t2 g and eg orbitals at iridium and 2 p orbitals at oxygen ions. The model takes into account anisotropic iridium-oxygen d -p and oxygen-oxygen p -p hopping processes, crystal-field splittings, spin-orbit coupling, and the on-site Coulomb interactions, both at iridium and at oxygen ions. We show that the predictions based on assumed idealized ionic configuration (with n0=5 +4 ×6 =29 electrons per IrO4 unit) do not explain well the independent ab initio data and the experimental data for Ba2IrO4 . Instead we find that the total electron density in the d -p states is smaller, n =29 -x 0 ). When we fix x =1 , the predictions for the d -p model become more realistic and weakly insulating antiferromagnetic ground state with the moments lying within IrO2 planes along (110) direction is found, in agreement with experiment and ab initio data. We also show that (i) holes delocalize over the oxygen orbitals and the electron density at iridium ions is enhanced; hence (ii) their eg orbitals are occupied by more than one electron and have to be included in the multiband d -p model describing iridates.

  4. A multi-band spectral subtraction-based algorithm for real-time noise cancellation applied to gunshot acoustics

    NASA Astrophysics Data System (ADS)

    Ramos, António L. L.; Holm, Sverre; Gudvangen, Sigmund; Otterlei, Ragnvald

    2013-06-01

    Acoustical sniper positioning is based on the detection and direction-of-arrival estimation of the shockwave and the muzzle blast acoustical signals. In real-life situations, the detection and direction-of-arrival estimation processes is usually performed under the influence of background noise sources, e.g., vehicles noise, and might result in non-negligible inaccuracies than can affect the system performance and reliability negatively, specially when detecting the muzzle sound under long range distance and absorbing terrains. This paper introduces a multi-band spectral subtraction based algorithm for real-time noise reduction, applied to gunshot acoustical signals. The ballistic shockwave and the muzzle blast signals exhibit distinct frequency contents that are affected differently by additive noise. In most real situations, the noise component is colored and a multi-band spectral subtraction approach for noise reduction contributes to reducing the presence of artifacts in denoised signals. The proposed algorithm is tested using a dataset generated by combining signals from real gunshots and real vehicle noise. The noise component was generated using a steel tracked military tank running on asphalt and includes, therefore, the sound from the vehicle engine, which varies slightly in frequency over time according to the engine's rpm, and the sound from the steel tracks as the vehicle moves.

  5. Dichotomy between the Hole and Electron Behavior in Multiband Superconductor FeSe Probed by Ultrahigh Magnetic Fields.

    PubMed

    Watson, M D; Yamashita, T; Kasahara, S; Knafo, W; Nardone, M; Béard, J; Hardy, F; McCollam, A; Narayanan, A; Blake, S F; Wolf, T; Haghighirad, A A; Meingast, C; Schofield, A J; Löhneysen, H v; Matsuda, Y; Coldea, A I; Shibauchi, T

    2015-07-10

    Magnetoresistivity ρ(xx) and Hall resistivity ρ(xy) in ultrahigh magnetic fields up to 88 T are measured down to 0.15 K to clarify the multiband electronic structure in high-quality single crystals of superconducting FeSe. At low temperatures and high fields we observe quantum oscillations in both resistivity and the Hall effect, confirming the multiband Fermi surface with small volumes. We propose a novel approach to identify from magnetotransport measurements the sign of the charge carriers corresponding to a particular cyclotron orbit in a compensated metal. The observed significant differences in the relative amplitudes of the quantum oscillations between the ρ(xx) and ρ(xy) components, together with the positive sign of the high-field ρ(xy), reveal that the largest pocket should correspond to the hole band. The low-field magnetotransport data in the normal state suggest that, in addition to one hole and one almost compensated electron band, the orthorhombic phase of FeSe exhibits an additional tiny electron pocket with a high mobility. PMID:26207500

  6. Nonthermal and geometric effects on the symmetric and anti-symmetric surface waves in a Lorentzian dusty plasma slab

    SciTech Connect

    Lee, Myoung-Jae; Jung, Young-Dae

    2015-02-15

    The nonthermal and geometric effects on the propagation of the surface dust acoustic waves are investigated in a Lorentzian dusty plasma slab. The symmetric and anti-symmetric dispersion modes of the dust acoustic waves are obtained by the plasma dielectric function with the spectral reflection conditions the slab geometry. The variation of the nonthermal and geometric effects on the symmetric and the anti-symmetric modes of the surface plasma waves is also discussed.

  7. Modulation instability of ion acoustic waves, solitons, and their interactions in nonthermal electron-positron-ion plasmas

    SciTech Connect

    Zhang Jiefang; Wang Yueyue; Wu Lei

    2009-06-15

    The propagation of ion acoustic waves in plasmas composed of ions, positrons, and nonthermally distributed electrons is investigated. By means of the reduction perturbation technique, a nonlinear Schroedinger equation is derived and the modulation instability of ion acoustic wave is analyzed, where the nonthermal parameter is found to be of significant importance. Furthermore, analytical expressions for the bright and dark solitons are obtained, and the interaction of multiple solitons is discussed.

  8. Gravity as main driver of non-thermal motions in massive star forming regions

    NASA Astrophysics Data System (ADS)

    Traficante, A.; Fuller, G. A.; Smith, R.; Billot, N.; Duarte-Cabral, A.; Peretto, N.; Molinari, S.; Pineda, J. E.

    2016-05-01

    The origin of the observed non-thermal motions in massive star forming regions is still unclear. These motions can originate from local turbulence or from self-gravity and the two scenarios lead to two different star formation mechanisms. The recent findings of Heyer et al. ([5]) have supported self-gravity as main driver of the non-thermal motions, although without a clear interpretation of the results. In this contribution we introduce a new formalism to describe the relation between gravity and kinetic motion in massive star formation. We show that the Heyer findings are a particular result of this description and have a direct physical interpretation. We applied this formalism to different surveys of massive star forming regions covering all spatial scales from giant molecular clouds down to massive cores, including new data from massive candidate starless clumps. The results presented in this contribution strongly support a chaotic, gravitationally driven global collapse scenario as massive star formation mechanism.

  9. Non-thermal x-ray emission from wire array z-pinches

    SciTech Connect

    Ampleford, David; Hansen, Stephanie B.; Jennings, Christopher Ashley; Webb, Timothy Jay; Harper-Slaboszewicz, V.; Loisel, Guillaume Pascal; Flanagan, Timothy McGuire; Bell, Kate Suzanne; Jones, Brent M.; McPherson, Leroy A.; Rochau, Gregory A.; Chittenden, Jeremy P.; Sherlock, Mark; Appelbe, Brian; Giuliani, John; Ouart, Nicholas; Seely, John

    2015-12-01

    We report on experiments demonstrating the transition from thermally-dominated K-shell line emission to non-thermal, hot-electron-driven inner-shell emission for z pinch plasmas on the Z machine. While x-ray yields from thermal K-shell emission decrease rapidly with increasing atomic number Z, we find that non-thermal emission persists with favorable Z scaling, dominating over thermal emission for Z=42 and higher (hn ≥ 17keV). Initial experiments with Mo (Z=42) and Ag (Z=47) have produced kJ-level emission in the 17-keV and 22-keV Kα lines respectively. We will discuss the electron beam properties that could excite these non - thermal lines. We also report on experiments that have attempted to control non - thermal K - shell line emission by modifying the wire array or load hardware setup.

  10. Observation of nonthermal energy distributions during the impulsive phase of solar flares

    NASA Technical Reports Server (NTRS)

    Seely, J. F.; Feldman, U.; Doschek, G. A.

    1987-01-01

    The Fe XXV resonance line and dielectronic satellite intensities have been measured as functions of time for several flares recorded by the Naval Research Laboratory crystal spectrometer (SOLFLEX) flown on the US Air Force P78-I spacecraft. The intensity ratios of the Fe XXV resonance line, the Fe XXIV n = 2 satellite line j, and the Fe XXIV n = 3 satellite line d13 indicate that nonthermal electron energy distributions occur during the impulsive phase of the flares. For the electron energies at which the j and d13 satellites are formed (4.7 and 5.8 keV, respectively), the electron energy distributions during the impulsive phase are observed to have a bump or to be nearly flat. For all of the flares that were studied, hard X-ray bursts occurred near the time of the nonthermal distributions observed in the SOLFLEX data.

  11. Compressive and rarefactive solitary waves in nonthermal two-component plasmas

    SciTech Connect

    Verheest, Frank; Hellberg, Manfred A.

    2010-10-15

    Using a Sagdeev pseudopotential formalism where nonlinear structures are stationary in a comoving frame, large ion-acoustic solitary waves and double layers have been studied in plasmas with positive ions and nonthermal electrons. The velocity range of positive, compressive solitary waves is limited by the ion density reaching infinite compression, whereas negative, rarefactive solitary waves and double layers can exist when the electron nonthermality exceeds a certain minimum. There are even regions of coexistence, the limits of which can be elucidated by considering the properties of the special Sagdeev pseudopotential at the acoustic speed. In particular, when the compositional parameters and Mach numbers admit only compressive or rarefactive solitary structures, these have to be superacoustic, their amplitude vanishing at the acoustic speed. When both compressive and rarefactive modes can occur, one of them is Korteweg-de Vries (KdV)-like, the other having a non-KdV character, with a finite amplitude at the acoustic speed.

  12. Solitary waves and rogue waves in a plasma with nonthermal electrons featuring Tsallis distribution

    NASA Astrophysics Data System (ADS)

    Wang, Yue-Yue; Li, Ji-Tao; Dai, Chao-Qing; Chen, Xin-Fen; Zhang, Jie-Fang

    2013-11-01

    In this Letter, we discuss the electron acoustic (EA) waves in plasmas, which consist of nonthermal hot electrons featuring the Tsallis distribution, and obtain the corresponding governing equation, that is, a nonlinear Schrödinger (NLS) equation. By means of Modulation Instability (MI) analysis of the EA waves, it is found that both electron acoustic solitary wave and rogue wave can exist in such plasmas. Basing on the Darboux transformation method, we derive the analytical expressions of nonlinear solutions of NLS equations, such as single/double solitary wave solutions and single/double rogue wave solutions. The existential regions and amplitude of solitary wave solutions and the rogue wave solutions are influenced by the nonextensive parameter q and nonthermal parameter α. Moreover, the interaction of solitary wave and how to postpone the excitation of rogue wave are also studied.

  13. Propagation of nonlinear coherent structures in a collisional magnetoplasma with nonthermal electrons and finite ion temperature

    SciTech Connect

    Masood, W.; Rizvi, H.; Imtiaz, N.

    2012-01-15

    Nonlinear electrostatic waves in dissipative magnetized electron-ion (e-i) plasmas are investigated employing the two fluid model. In this regard, Zakharov Kuznetsov Burgers (ZKB) equation is derived using the small amplitude perturbation expansion method. It is observed that the nonthermal electron population, obliqueness, ion thermal effects, and kinematic viscosity significantly alter the structure of obliquely propagating nonlinear ion acoustic shock waves in dissipative e-i magnetoplasmas. It is observed that the system can admit both compressive and rarefactive shocks. The condition for the formation of both types of shocks is also given. The present study may be useful to understand the nonlinear propagation characteristics of electrostatic shock structures in space environments where the nonthermal electrons have been observed by various satellite missions such as Voyager and Freja.

  14. Study of non-thermal plasma jet with dielectric barrier configuration in nitrogen and argon

    NASA Astrophysics Data System (ADS)

    Choo, C. Y.; Chin, O. H.

    2014-03-01

    Dielectric barrier discharge (DBD) is advantageous in generating non-thermal plasma at atmospheric pressure, as it avoids transition to thermal arc and dispenses with costly vacuum system. It has found useful applications in treating heat-sensitive materials such as plastics and living tissue. In this work, the discharge formed between the Pyrex glass layer and the ground electrode is extruded through a nozzle to form the non-thermal plasma jet. The DBD characteristics were investigated in terms of charge transferred and mean power dissipated per cycle when operated in nitrogen and argon at various flow rates and applied voltages. These characteristics were then correlated to the dimension of the plasma jet. The mean power dissipated in the DBD was below 7 W giving an efficiency of 17 %. The length of the plasma jet was greatly limited to below 1 cm due to the configuration of the DBD system and nozzle.

  15. Nonthermally Dominated Electron Acceleration during Magnetic Reconnection in a Low-beta Plasma

    SciTech Connect

    Li, Xiaocan

    2015-07-21

    This work was motivated by electron acceleration during solar flares. After some introductory remarks on proposed particle acceleration mechanisms and questions needing answers, dynamic simulations and simulation results are presented including energy spectra and the formation of the power law distribution. In summary, magnetic reconnection is highly efficient at converting the free magnetic energy stored in a magnetic shear and accelerating electrons to nonthermal energies in low-β regime. The nonthermal electrons have a dominant fraction and form power-law energy spectra with spectral index p ~ 1 in low-β regime. Electrons are preferentially accelerated along the curvature drift direction along the electric field induced by the reconnection outflow. The results can be applied to explain the observations of electron acceleration during solar flares.

  16. Effect of non-thermal atmospheric pressure plasma jet on human breast cancer cells

    NASA Astrophysics Data System (ADS)

    Mirpour, Shahriar; Nikkhah, Maryam; Pirouzmand, Somaye; Ghomi, Hamid Reza

    2012-10-01

    Nowadays, Non-thermal plasma enjoy a wide range of applications in biomedical fields such as Sterilization, Wound healing, Cancer treatment and etc. The aim of this paper is to study the effect of non-thermal atmospheric pressure plasma jet on breast cancer (MCF-7) cells. In this regard the effect of plasma on death of the cancer cells are explored experimentally. The plasma in this discharge is created by pulsed dc high voltage power supply with repetition rate of several tens of kilohertz which led to the inductively coupled plasma. The pure helium gas were used for formation of the plasma jet. MTT assay were used for quantification of death cells. The results showed that the cells death rate increase with plasma exposure time. This study confirm that plasma jet have significant effect on treatment of human breast cancer cells.

  17. Nonthermal electron-positron pairs and cold matter in the central engines of active galactic nuclei

    NASA Technical Reports Server (NTRS)

    Zdziarski, Andrzej A.

    1992-01-01

    The nonthermal e(+/-) pair model of the central engine of active galactic nuclei (AGNs) is discussed. The model assumes that nonthermal e(+/-) pairs are accelerated to highly relativistic energies in a compact region close to the central black hole and in the vicinity of some cold matter. The model has a small number of free parameters and explains a large body of AGN observations from EUV to soft gamma-rays. In particular, the model explains the existence of the UV bump, the soft X-rays excess, the canonical hard X-ray power law, the spectral hardening above about 10 keV, and some of the variability patterns in the soft and hard X-rays. In addition, the model explains the spectral steepening above about 50 keV seen in NGC 4151.

  18. Spherical ion acoustic waves in pair ion plasmas with nonthermal electrons

    NASA Astrophysics Data System (ADS)

    Selim, M. M.

    2016-04-01

    Propagation of nonplanar ion acoustic waves in a plasma composed of negative and positive ions and nonthermally distributed electrons is investigated using reductive perturbation theory. The spherical Kadomtsev-Petviashvili (SKP) equation which describes the dynamics of the nonlinear spherical ion acoustic waves is derived. It is found that compressive and rarefactive ion-acoustic solitary wave characteristics significantly depend on the density and mass ratios of the positive to negative ions, the nonthermal electron parameter, and the geometry factor. The possible regions for the existence of spherical ion acoustic waves are defined precisely for typical parameters of (H+, O2 -) and (H+, H-) plasmas in the D and F-regions of the Earth's ionosphere, as well as for laboratory plasma (Ar+, F-).

  19. Electrostatic solitary structures in dusty plasmas with nonthermal and superthermal electrons

    SciTech Connect

    Aoutou, Kamel; Tribeche, Mouloud; Zerguini, Taha Houssine

    2008-01-15

    A theoretical model is presented to show the existence, formation, and possible realization of arbitrary amplitude solitary potentials in a dusty plasma with both nonthermal and superthermal electrons. A physically meaningful {kappa}-like electron distribution function is outlined. It is shown that due to electron superthermality, the present dusty plasma model can support subsonic as well as supersonic electrostatic solitary waves involving cusped potential humps. Interestingly, one finds that the effect of increasing the spectral index {kappa} is to reduce and restrict the domain of allowable dust Mach numbers. An increase of the nonthermal parameter {alpha} would lead to a shift of this domain and a drastic restriction of the spectral index regime in which compressive and rarefactive solitons can coexist. Our results may provide an explanation for the strong spiky waveforms observed in auroral electric fields measurements by Viking and Fast.

  20. Non-thermal leptogenesis in a simple 5D SO(10) GUT

    SciTech Connect

    Fukuyama, Takeshi; Okada, Nobuchika E-mail: okadan@ua.edu

    2010-09-01

    We discuss non-thermal leptogenesis in the scheme of 5D orbifold SO(10) GUT with the smooth hybrid inflation. With unambiguously determined Dirac Yukawa couplings and an assumption for the neutrino mixing matrix of the tri-bimaximal from, we analyze baryon asymmetry of the universe via non-thermal leptogenesis in two typical cases for the light neutrino mass spectrum, the normal and inverted hierarchical cases. The resultant baryon asymmetry is obtained as a function of the lightest mass eigenvalue of the light neutrinos, and we find that a suitable amount of baryon asymmetry of the universe can be produced in the normal hierarchical case, while in the inverted hierarchical case the baryon asymmetry is too small to be consistent with the observation.