Science.gov

Sample records for energy spectrum adjustment

  1. Adjustable frequency drives save energy

    SciTech Connect

    Lambeth, J. ); Houston, J. )

    1991-05-01

    This article describes the use of an adjustable frequency drive for a water pump in a waste water treatment plant. In addition to reducing energy consumption, maintenance costs were reduced and the efficiency of the plant and the primary clarifier was increased. Variations in water level are reduced by improved control of the pump speed, rather than an on/off response to water level.

  2. Energy spectrum of sputtered uranium

    NASA Technical Reports Server (NTRS)

    Weller, R. A.; Tombrello, T. A.

    1977-01-01

    The fission track technique for detecting uranium 235 was used in conjunction with a mechanical time-of-flight spectrometer to measure the energy spectrum in the region 1 eV to 1 keV of material sputtered from a 93% enriched U-235 foil by 80 keV Ar-40(+) ions. The spectrum was found to exhibit a peak in the region 2-4 eV and to decrease approximately as E to the -1.77 power for E is approximately greater than 100 eV. The design, construction and resolution of the mechanical spectrometer are discussed and comparisons are made between the data and the predictions of the ramdom collision cascade model of sputtering.

  3. Frequency adjustable MEMS vibration energy harvester

    NASA Astrophysics Data System (ADS)

    Podder, P.; Constantinou, P.; Amann, A.; Roy, S.

    2016-10-01

    Ambient mechanical vibrations offer an attractive solution for powering the wireless sensor nodes of the emerging “Internet-of-Things”. However, the wide-ranging variability of the ambient vibration frequencies pose a significant challenge to the efficient transduction of vibration into usable electrical energy. This work reports the development of a MEMS electromagnetic vibration energy harvester where the resonance frequency of the oscillator can be adjusted or tuned to adapt to the ambient vibrational frequency. Micro-fabricated silicon spring and double layer planar micro-coils along with sintered NdFeB micro-magnets are used to construct the electromagnetic transduction mechanism. Furthermore, another NdFeB magnet is adjustably assembled to induce variable magnetic interaction with the transducing magnet, leading to significant change in the spring stiffness and resonance frequency. Finite element analysis and numerical simulations exhibit substantial frequency tuning range (25% of natural resonance frequency) by appropriate adjustment of the repulsive magnetic interaction between the tuning and transducing magnet pair. This demonstrated method of frequency adjustment or tuning have potential applications in other MEMS vibration energy harvesters and micromechanical oscillators.

  4. NREL Spectrum of Clean Energy Innovation (Brochure)

    SciTech Connect

    Not Available

    2011-09-01

    This brochure describes the NREL Spectrum of Clean Energy Innovation, which includes analysis and decision support, fundamental science, market relevant research, systems integration, testing and validation, commercialization and deployment. Through deep technical expertise and an unmatched breadth of capabilities, the National Renewable Energy Laboratory (NREL) leads an integrated approach across the spectrum of renewable energy innovation. From scientific discovery to accelerating market deployment, NREL works in partnership with private industry to drive the transformation of our nation's energy systems. NREL integrates the entire spectrum of innovation, including fundamental science, market relevant research, systems integration, testing and validation, commercialization, and deployment. Our world-class analysis and decision support informs every point on the spectrum. The innovation process at NREL is inter-dependent and iterative. Many scientific breakthroughs begin in our own laboratories, but new ideas and technologies may come to NREL at any point along the innovation spectrum to be validated and refined for commercial use.

  5. Energy adjustment methods applied to alcohol analyses.

    PubMed

    Johansen, Ditte; Andersen, Per K; Overvad, Kim; Jensen, Gorm; Schnohr, Peter; Sørensen, Thorkild I A; Grønbaek, Morten

    2003-01-01

    When alcohol consumption is related to outcome, associations between alcohol type and health outcomes may occur simply because of the ethanol in the beverage type. When one analyzes the consequences of consumption of beer, wine, and spirits, the total alcohol intake must therefore be taken into account. However, owing to the linear dependency between total alcohol intake and the alcohol content of each beverage type, the effects cannot be separated from each other or from the effect of ethanol. In nutritional epidemiology, similar problems regarding intake of macronutrients and total energy intake have been addressed, and four methods have been proposed to solve the problem: energy partition, standard, density, and residual. The aim of this study was to evaluate the usefulness of the energy adjustment methods in alcohol analyses by using coronary heart disease as an example. Data obtained from the Copenhagen City Heart Study were used. The standard and energy partition methods yielded similar results for continuous, and almost similar results for categorical, alcohol variables. The results from the density method differed, but nevertheless were concordant with these. Beer and wine drinkers, in comparison with findings for nondrinkers, had lower risk of coronary heart disease. Except for the case of men drinking beer, the effect seemed to be associated with drinking one drink per week. The standard method derives influence of substituting alcohol types at constant total alcohol intake and complements the estimates of adding consumption of a particular alcohol type to the total intake. For most diseases, the effect of ethanol predominates over that of substances in the beverage type, which makes the density method less relevant in alcohol analyses.

  6. Inclusive photon energy spectrum in B decays

    SciTech Connect

    Greub, C. )

    1992-02-01

    We present a theoretical estimate for the inclusive photon energy spectrum in direct decays of [ital B]-mesons taking into account both the charged current (CC) and flavour changing neutral current (FCNC) processes. It is shown that the various components in the inclusive spectrum can in principle be disentangled. In particular, the high energy part of the photon energy spectrum is dominated by the electromagnetic penguins. Its measurement could provide the first direct determination of the CKM matrix element [vert bar][ital V][sub [ital ts

  7. The energy spectrum in a barotropic atmosphere

    NASA Astrophysics Data System (ADS)

    Kurgansky, M. V.

    2008-03-01

    In a forced-dissipative barotropic model of the atmosphere on a spherical planet, by following mathematical techniques in (Thompson, P. D.: The equilibrium energy spectrum of randomly forced two-dimensional turbulence, Journal of the Atmospheric Sciences, 30, 1593-1598, 1973) but applying them in a novel context of the discrete spectrum on a rotating sphere, the "minus 2" energy spectrum for wavenumbers much greater than a characteristic wavenumber of the baroclinic forcing has been obtained if the forcing is taken in the simplest and most fundamental form. Some observation-based atmospheric kinetic energy spectra, with their slopes lying between "minus 2" and "minus 3" laws, are discussed from the perspective of the deduced "minus 2" energy spectrum.

  8. Energy spectrum control for modulated proton beams

    SciTech Connect

    Hsi, Wen C.; Moyers, Michael F.; Nichiporov, Dmitri; Anferov, Vladimir; Wolanski, Mark; Allgower, Chris E.; Farr, Jonathan B.; Mascia, Anthony E.; Schreuder, Andries N.

    2009-06-15

    In proton therapy delivered with range modulated beams, the energy spectrum of protons entering the delivery nozzle can affect the dose uniformity within the target region and the dose gradient around its periphery. For a cyclotron with a fixed extraction energy, a rangeshifter is used to change the energy but this produces increasing energy spreads for decreasing energies. This study investigated the magnitude of the effects of different energy spreads on dose uniformity and distal edge dose gradient and determined the limits for controlling the incident spectrum. A multilayer Faraday cup (MLFC) was calibrated against depth dose curves measured in water for nonmodulated beams with various incident spectra. Depth dose curves were measured in a water phantom and in a multilayer ionization chamber detector for modulated beams using different incident energy spreads. Some nozzle entrance energy spectra can produce unacceptable dose nonuniformities of up to {+-}21% over the modulated region. For modulated beams and small beam ranges, the width of the distal penumbra can vary by a factor of 2.5. When the energy spread was controlled within the defined limits, the dose nonuniformity was less than {+-}3%. To facilitate understanding of the results, the data were compared to the measured and Monte Carlo calculated data from a variable extraction energy synchrotron which has a narrow spectrum for all energies. Dose uniformity is only maintained within prescription limits when the energy spread is controlled. At low energies, a large spread can be beneficial for extending the energy range at which a single range modulator device can be used. An MLFC can be used as part of a feedback to provide specified energy spreads for different energies.

  9. Energy spectrum control for modulated proton beams

    PubMed Central

    Hsi, Wen C.; Moyers, Michael F.; Nichiporov, Dmitri; Anferov, Vladimir; Wolanski, Mark; Allgower, Chris E.; Farr, Jonathan B.; Mascia, Anthony E.; Schreuder, Andries N.

    2009-01-01

    In proton therapy delivered with range modulated beams, the energy spectrum of protons entering the delivery nozzle can affect the dose uniformity within the target region and the dose gradient around its periphery. For a cyclotron with a fixed extraction energy, a rangeshifter is used to change the energy but this produces increasing energy spreads for decreasing energies. This study investigated the magnitude of the effects of different energy spreads on dose uniformity and distal edge dose gradient and determined the limits for controlling the incident spectrum. A multilayer Faraday cup (MLFC) was calibrated against depth dose curves measured in water for nonmodulated beams with various incident spectra. Depth dose curves were measured in a water phantom and in a multilayer ionization chamber detector for modulated beams using different incident energy spreads. Some nozzle entrance energy spectra can produce unacceptable dose nonuniformities of up to ±21% over the modulated region. For modulated beams and small beam ranges, the width of the distal penumbra can vary by a factor of 2.5. When the energy spread was controlled within the defined limits, the dose nonuniformity was less than ±3%. To facilitate understanding of the results, the data were compared to the measured and Monte Carlo calculated data from a variable extraction energy synchrotron which has a narrow spectrum for all energies. Dose uniformity is only maintained within prescription limits when the energy spread is controlled. At low energies, a large spread can be beneficial for extending the energy range at which a single range modulator device can be used. An MLFC can be used as part of a feedback to provide specified energy spreads for different energies. PMID:19610318

  10. Psychological Adjustment of Siblings of Children with Autism Spectrum Disorder in Hong Kong.

    PubMed

    Chan, J Yn; Lai, K Yc

    2016-12-01

    Findings about the psychological adjustment of siblings of children with autism spectrum disorder have been inconsistent in western literature and little is known among non-western societies. This study explored the psychological adjustment of siblings of children with autism spectrum disorder in Hong Kong. A total of 116 families with siblings of children with autism spectrum disorders co-morbid with learning disability were included in the study. Parents completed questionnaires about sibling emotional and behavioural adjustment, and their own mental well-being, quality of life, and family functioning. Siblings completed a questionnaire on their relationship with the autistic proband. Parent ratings did not reveal any significant negative impact on the emotional and behavioural adjustment of the typically developing siblings of children with autism spectrum disorder, but there were concerns about their peer relationships and weak prosocial behaviours. When cut-off scores were used to screen for risk of mental health problems, a quarter of the siblings warranted further assessment. Parents' quality of life and family functioning were significant predictors of sibling adjustment. In managing children with autism spectrum disorder, it is necessary to bear in mind the adjustment of their siblings, especially their peer relationships and prosocial behaviour. Adopting a holistic approach to address the psychosocial needs of the parents can facilitate sibling adjustment.

  11. Energy spectrum of buoyancy-driven turbulence.

    PubMed

    Kumar, Abhishek; Chatterjee, Anando G; Verma, Mahendra K

    2014-08-01

    Using high-resolution direct numerical simulation and arguments based on the kinetic energy flux Π(u), we demonstrate that, for stably stratified flows, the kinetic energy spectrum E(u)(k)∼k(-11/5), the potential energy spectrum E(θ)(k)∼k(-7/5), and Π(u)(k)∼k(-4/5) are consistent with the Bolgiano-Obukhov scaling. This scaling arises due to the conversion of kinetic energy to the potential energy by buoyancy. For weaker buoyancy, this conversion is weak, hence E(u)(k) follows Kolmogorov's spectrum with a constant energy flux. For Rayleigh-Bénard convection, we show that the energy supply rate by buoyancy is positive, which leads to an increasing Π(u)(k) with k, thus ruling out Bolgiano-Obukhov scaling for the convective turbulence. Our numerical results show that convective turbulence for unit Prandt number exhibits a constant Π(u)(k) and E(u)(k)∼k(-5/3) for a narrow band of wave numbers.

  12. Factors Influencing Adjustment in Siblings of Children with Autism Spectrum Disorders

    ERIC Educational Resources Information Center

    Meyer, Katherine A.; Ingersoll, Brooke; Hambrick, David Z.

    2011-01-01

    Siblings of children with autism spectrum disorders (ASD) may be at an increased risk of adjustment problems. To examine possible predictors of adjustment difficulties in siblings, 70 mothers with at least one child with ASD and one typical child completed surveys of symptom severity in the child with ASD, impact of the child with ASD on the…

  13. Adaptive, full-spectrum solar energy system

    DOEpatents

    Muhs, Jeffrey D.; Earl, Dennis D.

    2003-08-05

    An adaptive full spectrum solar energy system having at least one hybrid solar concentrator, at least one hybrid luminaire, at least one hybrid photobioreactor, and a light distribution system operably connected to each hybrid solar concentrator, each hybrid luminaire, and each hybrid photobioreactor. A lighting control system operates each component.

  14. Energy spectrum of the electroweak Pomeron

    NASA Astrophysics Data System (ADS)

    Bartels, Jochen; Levin, Eugene; Siddikov, Marat

    2016-09-01

    In this paper we study the high energy behavior of electroweak Standard Model for a nonzero Weinberg angle θW . We evaluate the spectrum of the electroweak Pomeron and demonstrate that the leading intercept is given by αe .w .4 ln 2 and does not depend on the mixing angle θW. Due to its very small numerical value, we conclude that the high energy behavior of electroweak theory cannot be discussed without including the QCD Pomeron which, at sufficiently large energies, will dominate.

  15. Determination of neutron energy spectrum at KAMINI shielding experiment location.

    PubMed

    Sen, Sujoy; Bagchi, Subhrojit; Prasad, R R; Venkatasubramanian, D; Mohanakrishnan, P; Keshavamurty, R S; Haridas, Adish; Arul, A John; Puthiyavinayagam, P

    2016-09-01

    The neutron spectrum at KAMINI reactor south beam tube end has been determined using multifoil activation method. This beam tube is being used for characterizing neutron attenuation of novel shield materials. Starting from a computed guess spectrum, the spectrum adjustment/unfolding procedure makes use of minimization of a modified constraint function representing (a) least squared deviations between the measured and calculated reaction rates, (b) a measure of sharp fluctuations in the adjusted spectrum and (c) the square of the deviation of adjusted spectrum from the guess spectrum. The adjusted/unfolded spectrum predicts the reaction rates accurately. The results of this new procedure are compared with those of widely used SAND-II code.

  16. RESIDUAL ENERGY SPECTRUM OF SOLAR WIND TURBULENCE

    SciTech Connect

    Chen, C. H. K.; Bale, S. D.; Salem, C. S.; Maruca, B. A.

    2013-06-20

    It has long been known that the energy in velocity and magnetic field fluctuations in the solar wind is not in equipartition. In this paper, we present an analysis of 5 yr of Wind data at 1 AU to investigate the reason for this. The residual energy (difference between energy in velocity and magnetic field fluctuations) was calculated using both the standard magnetohydrodynamic (MHD) normalization for the magnetic field and a kinetic version, which includes temperature anisotropies and drifts between particle species. It was found that with the kinetic normalization, the fluctuations are closer to equipartition, with a mean normalized residual energy of {sigma}{sub r} = -0.19 and mean Alfven ratio of r{sub A} = 0.71. The spectrum of residual energy, in the kinetic normalization, was found to be steeper than both the velocity and magnetic field spectra, consistent with some recent MHD turbulence predictions and numerical simulations, having a spectral index close to -1.9. The local properties of residual energy and cross helicity were also investigated, showing that globally balanced intervals with small residual energy contain local patches of larger imbalance and larger residual energy at all scales, as expected for nonlinear turbulent interactions.

  17. The energy spectrum for stochastic eddies with gamma distribution

    NASA Astrophysics Data System (ADS)

    Kara, Rukiye; Caglar, Mine

    2012-09-01

    Lundgren (1982) showed that strained spiral vortex model for turbulent fine structure has exponential Kolmogorov energy spectrum form. Caglar (2007) has generalized Cinlar velocity field which defined a similar structure with Lundgren vortex and computed the energy spectrum. In this study, we investigate the energy spectrum of the stochastic velocity field using Gamma distribution for small scale eddies.

  18. Siblings of Youth with Autism Spectrum Disorders: Theoretical Perspectives on Sibling Relationships and Individual Adjustment

    ERIC Educational Resources Information Center

    McHale, Susan M.; Updegraff, Kimberly A.; Feinberg, Mark E.

    2016-01-01

    A burgeoning research literature investigates the sibling relationships of youth with autism spectrum disorder (ASD) and their implications for individual adjustment. Focusing on four relationship domains--behaviors, emotions, cognitions and involvement--and toward advancing this generally atheoretical literature, we review and apply tenets from a…

  19. Siblings of Youth with Autism Spectrum Disorders: Theoretical Perspectives on Sibling Relationships and Individual Adjustment

    ERIC Educational Resources Information Center

    McHale, Susan M.; Updegraff, Kimberly A.; Feinberg, Mark E.

    2016-01-01

    A burgeoning research literature investigates the sibling relationships of youth with autism spectrum disorder (ASD) and their implications for individual adjustment. Focusing on four relationship domains--behaviors, emotions, cognitions and involvement--and toward advancing this generally atheoretical literature, we review and apply tenets from a…

  20. ADAPTIVE FULL-SPECTRUM SOLOR ENERGY SYSTEMS

    SciTech Connect

    Byard D. Wood

    2004-04-01

    This RD&D project is a three year team effort to develop a hybrid solar lighting (HSL) system that transports solar light from a paraboloidal dish concentrator to a luminaire via a large core polymer fiber optic. The luminaire can be a device to distribute sunlight into a space for the production of algae or it can be a device that is a combination of solar lighting and electric lighting. A benchmark prototype system has been developed to evaluate the HSL system. Sunlight is collected using a one-meter paraboloidal concentrator dish with two-axis tracking. A secondary mirror consisting of eight planar-segmented mirrors directs the visible part of the spectrum to eight fibers (receiver) and subsequently to eight luminaires. This results in about 8,200 lumens incident at each fiber tip. Each fiber can illuminate about 16.7 m{sup 2} (180 ft{sup 2}) of office space. The IR spectrum is directed to a thermophotovoltaic (TPV) array to produce electricity. During this reporting period, the project team made advancements in the design of the second generation (Alpha) system. For the Alpha system, the eight individual 12 mm fibers have been replaced with a centralized bundle of 3 mm fibers. The TRNSYS Full-Spectrum Solar Energy System model has been updated and new components have been added. The TPV array and nonimaging device have been tested and progress has been made in the fiber transmission models. A test plan was developed for both the high-lumen tests and the study to determine the non-energy benefits of daylighting. The photobioreactor team also made major advancements in the testing of model scale and bench top lab-scale systems.

  1. Interface Circuit for Vibration Energy Harvesting with Adjustable Bias Voltage

    NASA Astrophysics Data System (ADS)

    Wei, J.; Lefeuvre, E.; Mathias, H.; Costa, F.

    2015-12-01

    This paper presents a new interface circuit for electrostatic vibration energy harvesting with adjustable bias voltage. An electronic switch is used to modify the circuit configuration so that the harvested energy increases the voltage across a biasing capacitor. Decrease of this biasing capacitor voltage occurs naturally due to the circuit imperfections. Such a control of the bias voltage enables to adjust the amount of energy converted by the variable capacitor on each cycle. This feature can be used to optimize the mechanical damping induced by the energy conversion process in order to maximize the harvested power. Another feature of this interface circuit is that it is capable to get high bias voltage whatever the battery voltage with low energy loss.

  2. Probing dark energy using convergence power spectrum and bi-spectrum

    NASA Astrophysics Data System (ADS)

    Dinda, Bikash R.

    2017-09-01

    Weak lensing convergence statistics is a powerful tool to probe dark energy. Dark energy plays an important role to the structure formation and the effects can be detected through the convergence power spectrum, bi-spectrum etc. One of the most promising and simplest dark energy model is the ΛCDM . However, it is worth investigating different dark energy models with evolving equation of state of the dark energy. In this work, detectability of different dark energy models from ΛCDM model has been explored through convergence power spectrum and bi-spectrum.

  3. Spectrum and energy levels of Mo VI

    NASA Astrophysics Data System (ADS)

    Reader, Joseph

    1998-05-01

    We have photographed the spectrum of the Rb-like ion Mo VI from 200 to 5300 Å with a sliding-spark discharge on our 10.7-m normal- and grazing-incidence spectrographs and have observed most of the yrast transitions given by Romanov et al.(N. P. Romanov and A. R. Striganov, Opt. Spectrosc. 27), 8 (1969). from a Penning discharge. We have obtained improved values for all of the energy levels. We confirm the odd levels of Kancerevicius et al.,(A. Kancerevicius et al.), Lithuanian Phys. J. 31, 143 (1991). but have revised a number of the even levels of Edlén et al.(B. Edlén et al.), Phys. Scr. 32, 215 (1985). The ionization energy of Edlén et al.,footnotemark[4] which had been called into question by Kancerevicius et al.footnotemark[3] as a result of their revision of the odd levels,footnotemark[4] is confirmed.

  4. Siblings of Youth with Autism Spectrum Disorders: Theoretical Perspectives on Sibling Relationships and Individual Adjustment

    PubMed Central

    McHale, Susan M.; Updegraff, Kimberly A.; Feinberg, Mark E.

    2015-01-01

    A burgeoning research literature investigates the sibling relationships of youth with Autism Spectrum Disorder (ASD) and their implications for individual adjustment. Focusing on four relationship domains-- behaviors, emotions, cognitions and involvement—and toward advancing this generally atheoretical literature, we review and apply tenets from a range of theoretical perspectives in an effort to illuminate the mechanisms underlying sibling relationship experiences and their adjustment implications. Our review suggests new directions for research to test theoretically-grounded hypotheses about how sibling relationships develop and are linked to individual adjustment. In addition, we consider how identifying underlying bio-psycho-social processes can aid in the development of interventions to promote warm and involved sibling relationships and positive youth development. PMID:26476737

  5. Reference data file for neutron spectrum adjustment and related radiation damage calculations

    SciTech Connect

    Zsolnay, E.M. ); Nolthenius, H.J.; Greenwood, L.R.; Szondi, E.J. )

    1990-08-01

    The REAL-88 interlaboratory exercise organized by IAEA resulted in a neutron metrology file. (NMF-90) comprising problem dependent data for benchmark neutron fields, furthermore, nuclear data and computer programs for neutron spectrum adjustment and radiation damage parameter calculations for the service life assessment of nuclear facilities. Calculation results of some experienced laboratories are also present. This paper describes and analyses the content of the neutron metrology file and outlines the most important problems and tasks to be solved in the field of radiation damage parameter calculations. 14 refs., 2 figs., 1 tab.

  6. The Cosmic Ray All-Particle Energy Spectrum

    NASA Astrophysics Data System (ADS)

    Lee, Jeongin

    1998-07-01

    The cosmic ray all-particle energy spectrum in the energy range from 10 GeV to ~100 TeV is presented here. Data were obtained from the Thin Ionisation Calorimeter (TIC) experiment flown on balloon for 76 hours in August 1994 over northern Canada. TIC was calibrated with a 2.3 TeV gold beam at Brookhaven National Laboratory in 1994 and with a 800 GeV proton beam at Fermi National Accelerator Laboratory in 1997. Extensive Monte Carlo simulations were conducted using GEANT/FLUKA to (1) evaluate the instrument performance including energy calibration and energy resolution, (2) calculate the energy deposited by interacting particles, and (3) reconstruct the cosmic ray all-particle energy spectrum. The derived integral spectral index of the cosmic ray spectrum is γCR=1.68± 0.01 from the measured deposited energy spectrum.

  7. Psychosocial Adjustment and Sibling Relationships in Siblings of Children with Autism Spectrum Disorder: Risk and Protective Factors

    ERIC Educational Resources Information Center

    Walton, Katherine M.; Ingersoll, Brooke R.

    2015-01-01

    This study compared sibling adjustment and relationships in siblings of children with Autism Spectrum Disorder (ASD-Sibs; n = 69) and siblings of children with typical development (TD-Sibs; n = 93). ASD-Sibs and TD-Sibs demonstrated similar emotional/behavioral adjustment. Older male ASD-Sibs were at increased risk for difficulties. Sibling…

  8. Psychosocial Adjustment and Sibling Relationships in Siblings of Children with Autism Spectrum Disorder: Risk and Protective Factors

    ERIC Educational Resources Information Center

    Walton, Katherine M.; Ingersoll, Brooke R.

    2015-01-01

    This study compared sibling adjustment and relationships in siblings of children with Autism Spectrum Disorder (ASD-Sibs; n = 69) and siblings of children with typical development (TD-Sibs; n = 93). ASD-Sibs and TD-Sibs demonstrated similar emotional/behavioral adjustment. Older male ASD-Sibs were at increased risk for difficulties. Sibling…

  9. On muon energy spectrum in muon groups underground

    NASA Technical Reports Server (NTRS)

    Bakatanov, V. N.; Chudakov, A. E.; Novoseltsev, Y. F.; Novoseltseva, M. V.; Stenkin, Y. V.

    1985-01-01

    A method is described which was used to measure muon energy spectrum characteristics in muon groups underground using mu-e decays recording. The Baksan Telescope's experimental data on mu-e decays intensity in muon groups of various multiplicities are analyzed. The experimental data indicating very flat spectrum does not however represent the total spectrum in muon groups. Obviously the muon energy spectrum depends strongly on a distance from the group axis. The core attraction effect makes a significant distortion, making the spectrum flatter. After taking this into account and making corrections for this effect the integral total spectrum index in groups has a very small depencence on muon multiplicity and agrees well with expected one: beta=beta (sub expected) = 1.75.

  10. Turbulent diffusion phase transition is due to singular energy spectrum.

    PubMed

    Wallstrom, T C

    1995-11-21

    The phase transition for turbulent diffusion, reported by Avellaneda and Majda [Avellaneda, M. & Majda, A. J. (1994) Philos. Trans. R. Soc. London A 346, 205-233, and several earlier papers], is traced to a modeling assumption in which the energy spectrum of the turbulent fluid is singularly dependent on the viscosity in the inertial range. Phenomenological models of turbulence and intermittency, by contrast, require that the energy spectrum be independent of the viscosity in the inertial range. When the energy spectrum is assumed to be consistent with the phenomenological models, there is no phase transition for turbulent diffusion.

  11. Turbulent diffusion phase transition is due to singular energy spectrum.

    PubMed Central

    Wallstrom, T C

    1995-01-01

    The phase transition for turbulent diffusion, reported by Avellaneda and Majda [Avellaneda, M. & Majda, A. J. (1994) Philos. Trans. R. Soc. London A 346, 205-233, and several earlier papers], is traced to a modeling assumption in which the energy spectrum of the turbulent fluid is singularly dependent on the viscosity in the inertial range. Phenomenological models of turbulence and intermittency, by contrast, require that the energy spectrum be independent of the viscosity in the inertial range. When the energy spectrum is assumed to be consistent with the phenomenological models, there is no phase transition for turbulent diffusion. Images Fig. 2 PMID:11607590

  12. One particularity of energy-angular secondary electrons spectrum

    NASA Astrophysics Data System (ADS)

    Borisov, S. S.; Zaitsev, S. I.

    2006-05-01

    In this work we discuss the problems of the energy-angular spectrum of backscattered and true secondary electrons simulation using the discrete (DLA) and the continuous (CLA) loss approximations. The presence of an angular spectrum artefact - the deviation from the sinusoidal distribution over the range of 177-18O° from the beam direction is shown.

  13. Energy spectrum of the NCAR-TIGCM lower thermosphere

    NASA Astrophysics Data System (ADS)

    Raskin, R. G.; Bums, A. G.; Killeen, T. L.; Roble, R. G.

    The spatial energy spectrum of the 110-150 km region is evaluated using a base case run of the NCAR-TIGCM. Available potential energy, divergent kinetic energy, and rotational kinetic energy are decomposed into spherical harmonic modes and the relative sizes of the reservoirs are compared to those observed in the lower atmosphere. The lower thermospheric spectrum is dominated by the signals of diurnal and semidiurnal tides, but dissipation occurs within the study region. The total potential energy exceeds the available potential energy by three orders of magnitude, but unlike the tropospheric case, more energy resides as kinetic energy than as available potential energy, a result that is typical of propagating tides. A modified definition of available potential energy appropriate for thermospheric heights is presented.

  14. Trigonal warping in bilayer graphene: Energy versus entanglement spectrum

    NASA Astrophysics Data System (ADS)

    Predin, Sonja; Wenk, Paul; Schliemann, John

    2016-03-01

    We present a mainly analytical study of the entanglement spectrum of Bernal-stacked graphene bilayers in the presence of trigonal warping in the energy spectrum. Upon tracing out one layer, the entanglement spectrum shows qualitative geometric differences to the energy spectrum of a graphene monolayer. However, topological quantities such as Berry-phase-type contributions to Chern numbers agree. The latter analysis involves not only the eigenvalues of the entanglement Hamiltonian but also its eigenvectors. We also discuss the entanglement spectra resulting from tracing out other sublattices. As a technical basis of our analysis, we provide closed analytical expressions for the full eigensystem of bilayer graphene in the entire Brillouin zone with a trigonally warped spectrum.

  15. Explosive Products EOS: Adjustment for detonation speed and energy release

    SciTech Connect

    Menikoff, Ralph

    2014-09-05

    Propagating detonation waves exhibit a curvature effect in which the detonation speed decreases with increasing front curvature. The curvature effect is due to the width of the wave profile. Numerically, the wave profile depends on resolution. With coarse resolution, the wave width is too large and results in a curvature effect that is too large. Consequently, the detonation speed decreases as the cell size is increased. We propose a modification to the products equation of state (EOS) to compensate for the effect of numerical resolution; i.e., to increase the CJ pressure in order that a simulation propagates a detonation wave with a speed that is on average correct. The EOS modification also adjusts the release isentrope to correct the energy release.

  16. Spectrum and energy transfer in steady Burgers turbulence

    NASA Technical Reports Server (NTRS)

    Girimaji, Sharath S.; Zhou, YE

    1995-01-01

    The spectrum, energy transfer, and spectral interactions in steady Burgers turbulence are studied using numerically generated data. The velocity field is initially random and the turbulence is maintained steady by forcing the amplitude of a band of low wavenumbers to be invariant in time, while permitting the phase to change as dictated by the equation. The spectrum, as expected, is very different from that of Navier-Stokes turbulence. It is demonstrated that the far range of the spectrum scales as predicted by Burgers. Despite the difference in their spectra, in matters of the spectral energy transfer and triadic interactions Burgers turbulence is similar to Navier-Stokes turbulence.

  17. High energy limit of single photon channeling radiation spectrum

    NASA Astrophysics Data System (ADS)

    Khokonov, M. Kh.; Efendiev, K. V.

    2006-11-01

    The properties of channeling radiation spectra for above 100 GeV electrons have been studied with account of multiple scattering and radiation cooling. It has been shown, that the shape of a spectrum does not depend neither on energy of electrons, nor on the atomic number of a target when the energy of electrons exceeds ˜1 TeV. The consideration is based on the uniform field approximation (UFA). Simple phenomenological expressions are presented which describe the radiation spectrum with good degree of accuracy. It has been shown, that the radiation length in the high energy limit depends weakly on the energy of incident electrons.

  18. High energy cosmic ray iron spectrum experiment

    NASA Technical Reports Server (NTRS)

    Arens, J. F.; Balasubrahmanyan, V. K.; Ormes, J. F.; Schmidt, W. K. H.; Simon, M.; Spiegelhauer, H.

    1978-01-01

    An instrument containing a gas Cerenkov counter and an iron ionization spectrometer was constructed in order to measure the cosmic-ray iron spectrum to 300 GeV/nucleon. Trajectories of particles were determined by entopistic or position-determining scintillator systems. The geometric factors with and without the gas Cerenkov counter were 0.3 and 0.6 sq m-ster, respectively. The instrument was successfully flown in June 1976 without the spectrometer and in October 1976 with the spectrometer from Palestine, Texas. The June flight yielded 14.5 h of data; the October flight, 25 h.

  19. The High Energy Spectrum of NGC 4151

    NASA Technical Reports Server (NTRS)

    Beckmann, V.; Gehrels, N.; Shrader, C.; Soldi, S.; Lubinski, P.; Zdziarski, A. A.; Petrucci, P.-O.; Malzac, J.

    2005-01-01

    We present first INTEGRAL observations of the type 1.5 Seyfert galaxy NGC 4151. Combining several INTEGRAL observations performed during 2003, totaling approximately 400 ksec of exposure time, allow us to study the spectrum in the 3 - 300 keV range. The measurements presented here reveal an overall spectrum from X-rays up to the soft gamma-rays that can be described by an absorbed (N(sub H) approximately equal to 5 x 10(exp 22) per square centimeter) and non-variable thermal component, plus a Fe Kalpha line, and an exponential cutoff occurs at 110 keV, consistent with earlier claims. The Galactic hydrogen column density in the line of sight is N(sub H), Gal approximately equal to 2.1 x 10 (exp 20) per square centimeter. The time resolved analysis shows little variation of the spectral parameters. The comparison with CGRO/OSSE data shows that the same spectral model can be applied over a time span of 15 years, while the flux varied by a factor of 2. Applying a Compton reflection component improves the model fit to the INTEGRAL data. Nonetheless the data available to date cannot significantly confirm or exclude the existence of reflection, nor is a high iron overabundance in the absorber, as had been previously suggested, clearly detectable.

  20. Passive wide spectrum harmonic filter for adjustable speed drives in oil and gas industry

    NASA Astrophysics Data System (ADS)

    Al Jaafari, Khaled Ali

    Non-linear loads such as variable speed drives constitute the bulky load of oil and gas industry power systems. They are widely used in driving induction and permanent magnet motors for variable speed applications. That is because variable speed drives provide high static and dynamic performance. Moreover, they are known of their high energy efficiency and high motion quality, and high starting torque. However, these non-linear loads are main sources of current and voltage harmonics and lower the quality of electric power system. In fact, it is the six-pulse and twelve-pulse diode and thyristor rectifiers that spoil the AC power line with the dominant harmonics (5th, 7th, 11th). They provide DC voltage to the inverter of the variable speed drives. Typical problems that arise from these harmonics are Harmonic resonances', harmonic losses, interference with electronic equipment, and line voltage distortion at the Point of Common Coupling (PCC). Thus, it is necessary to find efficient, reliable, and economical harmonic filters. The passive filters have definite advantage over active filters in terms of components count, cost and reliability. Reliability and maintenance is a serious issue in drilling rigs which are located in offshore and onshore with extreme operating conditions. Passive filters are tuned to eliminate a certain frequency and therefore there is a need to equip the system with more than one passive filter to eliminate all unwanted frequencies. An alternative solution is Wide Spectrum Harmonic passive filter. The wide spectrum harmonic filters are becoming increasingly popular in these applications and found to overcome some of the limitations of conventional tuned passive filter. The most important feature of wide spectrum harmonic passive filters is that only one capacitor is required to filter a wide range of harmonics. Wide spectrum filter is essentially a low-pass filter for the harmonic at fundamental frequency. It can also be considered as a

  1. On the Linearly-Balanced Kinetic Energy Spectrum

    NASA Technical Reports Server (NTRS)

    Lu, Huei,-Iin; Robertson, F. R.

    1999-01-01

    It is well known that the earth's atmospheric motion can generally be characterized by the two dimensional quasi-geostrophic approximation, in which the constraints on global integrals of kinetic energy, entrophy and potential vorticity play very important roles in redistributing the wave energy among different scales of motion. Assuming the hypothesis of Kolmogrov's local isotropy, derived a -3 power law of the equilibrium two-dimensional kinetic energy spectrum that entails constant vorticity and zero energy flows from the energy-containing wave number up to the viscous cutoff. In his three dimensional quasi-geostrophic theory, showed that the spectrum function of the vertical scale turbulence - expressible in terms of the available potential energy - possesses the same power law as the two dimensional kinetic energy spectrum. As the slope of kinetic energy spectrum in the inertial range is theoretically related to the predictability of the synoptic scales (Lorenz, 1969), many general circulation models includes a horizontal diffusion to provide reasonable kinetic energy spectra, although the actual power law exhibited in the atmospheric general circulation is controversial. Note that in either the atmospheric modeling or the observational analyses, the proper choice of wave number Index to represent the turbulence scale Is the degree of the Legendre polynomial.

  2. On the Linearly-Balanced Kinetic Energy Spectrum

    NASA Technical Reports Server (NTRS)

    Lu, Huei,-Iin; Robertson, F. R.

    1999-01-01

    It is well known that the earth's atmospheric motion can generally be characterized by the two dimensional quasi-geostrophic approximation, in which the constraints on global integrals of kinetic energy, entrophy and potential vorticity play very important roles in redistributing the wave energy among different scales of motion. Assuming the hypothesis of Kolmogrov's local isotropy, derived a -3 power law of the equilibrium two-dimensional kinetic energy spectrum that entails constant vorticity and zero energy flows from the energy-containing wave number up to the viscous cutoff. In his three dimensional quasi-geostrophic theory, showed that the spectrum function of the vertical scale turbulence - expressible in terms of the available potential energy - possesses the same power law as the two dimensional kinetic energy spectrum. As the slope of kinetic energy spectrum in the inertial range is theoretically related to the predictability of the synoptic scales (Lorenz, 1969), many general circulation models includes a horizontal diffusion to provide reasonable kinetic energy spectra, although the actual power law exhibited in the atmospheric general circulation is controversial. Note that in either the atmospheric modeling or the observational analyses, the proper choice of wave number Index to represent the turbulence scale Is the degree of the Legendre polynomial.

  3. Energy spectrum of the bound polaron

    NASA Astrophysics Data System (ADS)

    Adamowski, Janusz

    1985-08-01

    An eigenvalue problem for an electron interacting with a Coulomb center and a field of LO phonons is solved by a method of optimized canonical transformation. This method can be applied to arbitrary values of the electron-phonon coupling constant α. The energy eigenvalues for the 1s through 4f states have been calculated as function of α and of the ratio R of the donor rydberg mee4/2ħ2ɛ20 to the LO-phonon energy ħω. These values are the upper bounds to the energy E1s of the ground state as well to all the energy levels of the excited states lying below E1s+ħω. In a broad range of α and R, the present upper bounds are lower than previous variational results for the states 1s, 2s, and 2p. The energy levels for the 3s-4f states have been calculated for the first time by variational means. The calculated energy eigenvalues Enl lie always below the corresponding hydrogenlike levels, i.e., Enl/ħω<=-α-R/n2, where n and l are the principal and angular momentum quantum numbers, respectively. For all values of α and R, the following sequence of the energy levels for a given n has been obtained: Enl<=Enl' if l>l'. In particular, it leads to the positive Lamb shift E2s-E2p. The model of the bound polaron has been applied to the description of shallow donor spectra. The calculated values agree rather well with the measured 1s-2p transition energies for CdTe and ZnSe, and 1s-2s transition energies for CdS. For AgBr, AgCl, and CdF2 the upper bounds for the 1s level are too low, but the 2p-3p energy differences agree well with the experimental data. It means that the short-range donor potential neglected in the polaron model is repulsive for the considered impurities in the ionic crystals.

  4. Energy Spectrum of Nonthermal Electrons Accelerated at a Plane Shock

    NASA Astrophysics Data System (ADS)

    Kang, Hyesung

    2011-04-01

    We calculate the energy spectra of cosmic ray (CR) protons and electrons at a plane shock with quasi-parallel magnetic fields,using time-dependent, diffusive shock acceleration (DSA) simulations,including energy losses via synchrotron emission and Inverse Compton (IC) scattering. A thermal leakage injection model and a Bohm type diffusion coefficient are adopted. The electron spectrum at the shock becomes steady after the DSA energy gains balance the synchrotron/IC losses, and it cuts off at the equilibrium momentum p_{eq}.In the postshock region the cutoff momentum of the electron spectrum decreases with the distance from the shock due to the energy losses and the thickness of the spatial distribution of electrons scales as p^{-1}. Thus the slope of the downstream integrated spectrum steepens by one power of p for p_{br}spectrum exhibit a concave curvature and deviate from the canonical test-particle power-law, and the upstream integrated electron spectrum could dominate over the downstream integrated spectrum near the cutoff momentum. Thus the spectral shape near the cutoff of X-ray synchrotron emission could reveal a signature of nonlinear DSA.

  5. NREL Spectrum of Clean Energy Innovation: Issue 3 (Book)

    SciTech Connect

    Not Available

    2012-11-01

    This quarterly magazine is dedicated to stepping beyond the technical journals to reveal NREL's vital work in a real-world context for our stakeholders. Continuum provides insights into the latest and most impactful clean energy innovations, while spotlighting those talented researchers and unique facilities that make it all happen. This edition focuses on the NREL Spectrum of Clean Energy Innovation.

  6. Hadron intensity and energy spectrum at 4380 m above level

    NASA Technical Reports Server (NTRS)

    Cananov, S. D.; Chadranyan, E. K.; Khizanishvili, L. A.; Ladaria, N. K.; Roinishvili, N. N.

    1985-01-01

    The flux value of hadrons with E (sup gamma) h or = 5 TeV, where E (sup gamma) h or = is the energy transferred into electromagnetic component is presented. It is shown that the energy spectrum slope beta of hadrons with E h or = 20 TeV is equal to 1.9.

  7. Energy spectrum of a Langevin oscillator

    NASA Astrophysics Data System (ADS)

    Mishin, Y.; Hickman, J.

    2016-12-01

    We derive analytical solutions for the autocorrelation and cross-correlation functions of the kinetic, potential, and total energy of a Langevin oscillator. These functions are presented in both the time and frequency domains and validated by independent numerical simulations. The results are applied to address the long-standing issue of temperature fluctuations in canonical systems.

  8. Energy spectrum analysis - A model of echolocation processing. [in animals

    NASA Technical Reports Server (NTRS)

    Johnson, R. A.; Titlebaum, E. L.

    1976-01-01

    The paper proposes a frequency domain approach based on energy spectrum analysis of the combination of a signal and its echoes as the processing mechanism for the echolocation process used by bats and other animals. The mechanism is a generalized wide-band one and can account for the large diversity of wide-band signals used for orientation. The coherency in the spectrum of the signal-echo combination is shown to be equivalent to correlation.

  9. Energy spectrum analysis - A model of echolocation processing. [in animals

    NASA Technical Reports Server (NTRS)

    Johnson, R. A.; Titlebaum, E. L.

    1976-01-01

    The paper proposes a frequency domain approach based on energy spectrum analysis of the combination of a signal and its echoes as the processing mechanism for the echolocation process used by bats and other animals. The mechanism is a generalized wide-band one and can account for the large diversity of wide-band signals used for orientation. The coherency in the spectrum of the signal-echo combination is shown to be equivalent to correlation.

  10. Energy spectrum of black holes: A new view

    NASA Astrophysics Data System (ADS)

    Majhi, Abhishek

    2017-01-01

    Energy of a black hole is usually quantized by invoking some area quantization scheme after expressing the energy in terms of the horizon area. However, in this approach one has to quantize the local and asymptotic energy of the black hole separately and the two results do not manifest any physical correspondence with each other. Here, as opposed to this practice, we find the unique energy spectrum of black holes by adopting a top-down approach. The physical links among the underlying quantum theory, statistical mechanics and thermodynamics of the black hole horizon play the central role in determining the energy spectrum. The energy spectrum that we obtain explicitly reveals the correspondence between asymptotic and local observations through the presence of the surface gravity of the horizon as a parameter in the spectrum, rather than being expressed as a function of area and consequently getting quantized in the usual approach. Thus, our result presents a new view as far as black hole energy quantization is concerned. The calculations are performed using the quantum geometric description of black hole horizons as laid down by loop quantum gravity.

  11. On the interpretation of the geomagnetic energy spectrum

    USGS Publications Warehouse

    Benton, E.R.; Alldredge, L.R.

    1987-01-01

    Two recent high-degree magnetic energy spectra, based mostly on MAGSAT data, are compared and found to agree very well out to order and degree n = 15, but the spectrum remains somewhat uncertain for higher degrees. The hypothesis that a primary break in the slope of the spectrum, plotted semi-logarithmically, is due to a transition from dominance by core sources to dominance by crustal magnetization is tested. Simple arrays of dipoles and current loops are found whose combined fields fit the spectrum. Two distinctly different ranges of source depth are found to be adequate. Because one range is shallow and the other deep, the hypothesis is supported. ?? 1987.

  12. Spectrum of energy depositions in the Auger Water Cherenkov Detector

    NASA Astrophysics Data System (ADS)

    Salazar, Humberto

    1999-08-01

    The measured spectrum of energy depositions in a Water Cherenkov Detector (WCD) prototype for the Pierre Auger Observatory is presented. A WCD (area 10 m2 )is located in the Puebla University campus at a depth of 800 g/cm2 (2200 m above sea level). Differential and integral spectra in a wide energy deposition range (0.5 - 150 of vertical equivalent muons) are presented. The problem of the WCD "self calibration" procedure (by rate of the muon events) is discussed. The characteristic change of the slopes of the differential spectrum at the transition from single muon signals to EAS signals is also discussed. The measured energy deposition spectrum at extreme signals is used to estimate the linearity of the response of the WCD PMTs. Key words: Auger array, water Cherenkov detector, extensive air showers

  13. ENERGY SPECTRUM AND CHEMICAL COMPOSITION OF ULTRAHIGH ENERGY COSMIC RAYS FROM SEMI-RELATIVISTIC HYPERNOVAE

    SciTech Connect

    Liu Ruoyu; Wang Xiangyu

    2012-02-10

    It has been suggested that hypernova remnants, with a substantial amount of energy in semi-relativistic ejecta, can accelerate intermediate mass or heavy nuclei to ultrahigh energies and provide a sufficient amount of energy in cosmic rays to account for the observed flux. We here calculate the expected energy spectrum and chemical composition of ultrahigh energy cosmic rays from such semi-relativistic hypernovae. With a chemical composition equal to that of the hypernova ejecta and a flat or hard spectrum for cosmic rays at the sources, the spectrum and composition of the propagated cosmic rays observed at the Earth can be compatible with the measurements by the Pierre Auger Observatory.

  14. Relations between Executive Functions, Social Impairment, and Friendship Quality on Adjustment among High Functioning Youth with Autism Spectrum Disorder

    ERIC Educational Resources Information Center

    Lieb, Rebecca W.; Bohnert, Amy M.

    2017-01-01

    High functioning adolescents with Autism Spectrum Disorder (ASD) often have adjustment difficulties, specifically loneliness and depression. To better understand contributing factors, the current study evaluated associations between several Executive Function (EF) domains, social impairment, and friendship quality on depressive symptoms and…

  15. Energy Spectrum in the Dissipation Range of Fluid Turbulence

    NASA Technical Reports Server (NTRS)

    Martinez, D. O.; Chen, S.; Doolen, G. D.; Kraichnan, R. H.; Wang, L.-P.; Zhou, Y.

    1996-01-01

    High resolution, direct numerical simulations of the three-dimensional incompressible Navier-Stokes equations are carried out to study the energy spectrum in the dissipation range. An energy spectrum of the form A(k/k( sub d))(sup alpha) exp[- betak/k(sub d) is confirmed. The possible values of the parameters alpha and beta, as well as their dependence on Revnolds numbers and length scales, are investigated, showing good agreement with recent theoretical predictions. A "bottleneck'-type effect is reported at k/k(sub d) approximately 4, exhibiting a possible transition from near-dissipation to far- dissipation.

  16. Parameterizations of Pion Energy Spectrum in Nucleon-Nucleon Collisions

    NASA Technical Reports Server (NTRS)

    Cucinotta, Franics A.; Wilson, John W.; Norbury, John W.

    1998-01-01

    The effects of pion (PI) production are expected to play an important role in radiation exposures in the upper atmosphere or on the Martian surface. Nuclear databases for describing pion production are developed for radiation transport codes to support these studies. We analyze the secondary energy spectrum of pions produced in nucleon-nucleon (NN) collisions in the relativistic one-pion exchange model. Parametric formulas of the isospin cross sections for one-pion production channels are discussed and are used to renormalize the model spectrum. Energy spectra for the deuteron related channels (NN yields dPi) are also described.

  17. High Energy Atmospheric Neutrino Fluxes From a Realistic Primary Spectrum

    NASA Astrophysics Data System (ADS)

    Campos Penha, Felipe; Dembinski, Hans; Gaisser, Thomas K.; Tilav, Serap

    2016-03-01

    Atmospheric neutrino fluxes depend on the energy spectrum of primary nucleons entering the top of the atmosphere. Before the advent of AMANDA and the IceCube Neutrino Observatory, measurements of the neutrino fluxes were generally below ~ 1TeV , a regime in which a simple energy power law sufficed to describe the primary spectrum. Now, IceCube's muon neutrino data extends beyond 1PeV , including a combination of neutrinos from astrophysical sources with background from atmospheric neutrinos. At such high energies, the steepening at the knee of the primary spectrum must be accounted for. Here, we describe a semi-analytical approach for calculating the atmospheric differential neutrino fluxes at high energies. The input is a realistic primary spectrum consisting of 4 populations with distinct energy cutoffs, each with up to 7 representative nuclei, where the parameters were extracted from a global fit. We show the effect of each component on the atmospheric neutrino spectra, above 10TeV . The resulting features follow directly from recent air shower measurements included in the fit. Felipe Campos Penha gratefully acknowledges financial support from CAPES (Processo BEX 5348/14-5), CNPq (Processo 142180/2012-2), and the Bartol Research Institute.

  18. Examination of energy spectrum acquisition method using shielded radiopharmaceutical syringes.

    PubMed

    Uto, Tomoyuki

    2009-09-20

    I previously reported on a spectrum sampling method with shielded syringes before use, although the report included only data obtained using technetium-99m. In this study, we sampled the energy spectrum in a similar manner using thallium-201, iodine-123, and gallium-67. In spectrum sampling, a radioisotopic source in a cylindrical shield is located midway between two opposed gamma-camera detectors equipped with collimators. An unshielded syringe before use emits excessive radiation and makes count rates too high to obtain accurate photopeak values. With a shielded syringe, we can sample the spectrum of radiation leaked from the needle side of the syringe and the unshielded part of its plunger side. Consequently, the detectors are exposed to lower-dose gamma rays and probably offer count rates appropriate to measure accurate photopeak values. The study results show the general validity of spectrum sampling and photopeak acquisition in our method. However, a syringe should be located accurately perpendicular to each detector; otherwise, gamma rays did not reach the detectors in some cases, resulting in measurement failures. In addition, when low-energy collimators are used for sampling from (123)I sources, photopeak values depend on penetration. More accurate measurements require the use of high-energy collimators.

  19. Energy Spectrum of Cosmic-Ray Electrons at TeV Energies

    SciTech Connect

    Aharonian, F.; Akhperjanian, A. G.; Sahakian, V.; Barres de Almeida, U.; Chadwick, P. M.; Cheesebrough, A.; Dickinson, H. J.; Hadjichristidis, C.; Keogh, D.; McComb, T. J. L.; Nolan, S. J.; Orford, K. J.; Osborne, J. L.; Rayner, S. M.; Rulten, C. B.; Spangler, D.; Ward, M.; Bazer-Bachi, A. R.; Borrel, V.; Olive, J-F.

    2008-12-31

    The very large collection area of ground-based {gamma}-ray telescopes gives them a substantial advantage over balloon or satellite based instruments in the detection of very-high-energy (>600 GeV) cosmic-ray electrons. Here we present the electron spectrum derived from data taken with the High Energy Stereoscopic System (H.E.S.S.) of imaging atmospheric Cherenkov telescopes. In this measurement, the first of this type, we are able to extend the measurement of the electron spectrum beyond the range accessible to direct measurements. We find evidence for a substantial steepening in the energy spectrum above 600 GeV compared to lower energies.

  20. Energy spectrum of cosmic-ray electrons at TeV energies.

    PubMed

    Aharonian, F; Akhperjanian, A G; Barres de Almeida, U; Bazer-Bachi, A R; Becherini, Y; Behera, B; Benbow, W; Bernlöhr, K; Boisson, C; Bochow, A; Borrel, V; Braun, I; Brion, E; Brucker, J; Brun, P; Brucker, R; Bulik, T; Büsching, I; Boutelier, T; Carrigan, S; Chadwick, P M; Charbonnier, A; Chaves, R C G; Cheesebrough, A; Chounet, L M; Clapson, A C; Coignet, G; Costamante, L; Dalton, M; Degrange, B; Deil, C; Dickinson, H J; Djannati-Ataï, A; Domainko, W; Drury, L O'C; Dubois, F; Dubus, G; Dyks, J; Dyrda, M; Egberts, K; Emmanoulopoulos, D; Espigat, P; Farnier, C; Feinstein, F; Fiasson, A; Fontaine, G; Füsling, M; Gabici, S; Gallant, Y A; Gérard, L; Giebels, B; Glicenstein, J F; Glück, B; Goret, P; Hadjichristidis, C; Hauser, D; Hauser, M; Heinz, S; Heinzelmann, G; Henri, G; Hermann, G; Hinton, J A; Hoffmann, A; Hofmann, W; Holleran, M; Hoppe, S; Horns, D; Jacholkowska, A; de Jager, O C; Jung, I; Katarzyński, K; Kaufmann, S; Kendziorra, E; Kerschhaggl, M; Khangulyan, D; Khélifi, B; Keogh, D; Komin, Nu; Kosack, K; Lamanna, G; Lenain, J P; Lohse, T; Marandon, V; Martin, J M; Martineau-Huynh, O; Marcowith, A; Maurin, D; McComb, T J L; Medina, C; Moderski, R; Moulin, E; Naumann-Godo, M; de Naurois, M; Nedbal, D; Nekrassov, D; Niemiec, J; Nolan, S J; Ohm, S; Olive, J F; de Oña Wilhelmi, E; Orford, K J; Osborne, J L; Ostrowski, M; Panter, M; Pedaletti, G; Pelletier, G; Petrucci, P O; Pita, S; Pühlhofer, G; Punch, M; Quirrenbach, A; Raubenheimer, B C; Raue, M; Rayner, S M; Renaud, M; Rieger, F; Ripken, J; Rob, L; Rosier-Lees, S; Rowell, G; Rudak, B; Rulten, C B; Ruppel, J; Sahakian, V; Santangelo, A; Schlickeiser, R; Schöck, F M; Schröder, R; Schwanke, U; Schwarzburg, S; Schwemmer, S; Shalchi, A; Skilton, J L; Sol, H; Spangler, D; Stawarz, Ł; Steenkamp, R; Stegmann, C; Superina, G; Tam, P H; Tavernet, J P; Terrier, R; Tibolla, O; van Eldik, C; Vasileiadis, G; Venter, C; Vialle, J P; Vincent, P; Vivier, M; Völk, H J; Volpe, F; Wagner, S J; Ward, M; Zdziarski, A A; Zech, A

    2008-12-31

    The very large collection area of ground-based gamma-ray telescopes gives them a substantial advantage over balloon or satellite based instruments in the detection of very-high-energy (>600 GeV) cosmic-ray electrons. Here we present the electron spectrum derived from data taken with the High Energy Stereoscopic System (H.E.S.S.) of imaging atmospheric Cherenkov telescopes. In this measurement, the first of this type, we are able to extend the measurement of the electron spectrum beyond the range accessible to direct measurements. We find evidence for a substantial steepening in the energy spectrum above 600 GeV compared to lower energies.

  1. High energy primary electron spectrum observed by the emulsion chamber

    NASA Technical Reports Server (NTRS)

    Nishimura, J.; Fujii, M.; Aizu, H.; Hiraiwa, N.; Taira, T.; Kobayashi, T.; Niu, K.; Koss, T. A.; Lord, J. J.; Golden, R. L.

    1978-01-01

    A detector of the emulsion chamber type is used to measure the energy spectrum of cosmic-ray electrons. Two large emulsion chambers, each having an area of 40 by 50 sq cm, are exposed for about 25.5 hr at an average pressure altitude of 3.9 mbar. About 500 high-energy cascades (no less than about 600 GeV) are detected by searching for dark spots on the X-ray films. A power-law energy dependence formula is derived for the spectrum of primary cosmic-ray electrons in the energy region over 100 GeV. The results are in good agreement with the transition curves obtained previously by theoretical and Monte Carlo calculations.

  2. Limiting energy spectrum of a saturated radiation belt

    NASA Technical Reports Server (NTRS)

    Schulz, Michael; Davidson, Gerald T.

    1988-01-01

    The condition for magnetospheric wave growth in the presence of anisotropic charged particle distributions is used to extend the Kennel-Petschek theory that traditionally imposes an upper bound on the integral flux of charged particles at energies above a certain threshold to provide a limit on the differential flux at any energy above this threshold. A closed-form expression is derived for the limiting energy spectrum consistent with marginal occurrence of a magnetospheric maser at all wave frequencies below a certain fraction of the electron or proton gyrofrequency. The bounded integral can be recast in such a way that repeated differentiations with respect to v(parallel) actually generate a closed expression for the limiting form of the velocity space distribution, and thus for the limiting energy spectrum of the corresponding particles, whenever the anisotropy parameter is an integer.

  3. Energy Transport in Quantum Systems with Discrete Spectrum

    NASA Astrophysics Data System (ADS)

    Levin, George; Jones, Wesley; Walczak, Kamil; Yerkes, Kirk

    2012-02-01

    Energy transport in quantum system driven by stochastic perturbations is examined. One of the goals of this study is to determine how the Landauer channels can be defined in a system with discrete energy spectrum. A model describes a particle trapped in a confining potential and subjected to a stochastic perturbation localized off-center of the potential well. The perturbation pumps energy into the system which results in non-zero average energy flux between different regions of the confining potential. The energy flux can be defined in terms of quantum advection modes, where each mode is associated with an off-diagonal element of the density matrix and carries a finite, quantized amount of energy per unit of the probability flux. Statistical correlations between different modes and the net energy flux will be discussed.

  4. Monte Carlo Estimate to Improve Photon Energy Spectrum Reconstruction

    NASA Astrophysics Data System (ADS)

    Sawchuk, S.

    Improvements to planning radiation treatment for cancer patients and quality control of medical linear accelerators (linacs) can be achieved with the explicit knowledge of the photon energy spectrum. Monte Carlo (MC) simulations of linac treatment heads and experimental attenuation analysis are among the most popular ways of obtaining these spectra. Attenuation methods which combine measurements under narrow beam geometry and the associated calculation techniques to reconstruct the spectrum from the acquired data are very practical in a clinical setting and they can also serve to validate MC simulations. A novel reconstruction method [1] which has been modified [2] utilizes a Simpson's rule (SR) to approximate and discretize (1)

  5. Anisotropy and the knee of the energy spectrum

    NASA Technical Reports Server (NTRS)

    Clay, R. W.

    1985-01-01

    The measured cosmic ray energy spectrum exhibits clear structure (the knee) at approx 3 x 10 to the 15th power eV (sea level shower size approx 3 x 10 to the 5th power particles). Additionally, at energies in this general region, there occur apparent changes in shower development such that the observed characteristics of showers at this energy appear different to those characteristics observed at somewhat higher energies. At energies just below this region, the cosmic ray anisotropy amplitude apparently begins a progressive increase with energy. The latter effect does not clearly fit with the first two since there appears to be no significant change exactly at the knee. However, the phase of the first harmonic of the anisotropy appears to show a substantial change just where the energy spectrum shows structure and in the middle of the shower development changes. The first harmonic phase appears to change from approx. 18 hours R.A. to approx. 5 hours R.A. as the energy of observation moves through the knee. In this paper the latter change is examined in some detail by taking into account information contained in the second harmonic of the anisotropy.

  6. Spectrum tailoring of the neutron energy spectrum in the context of delayed neutron detection

    SciTech Connect

    Koehler, William E; Tobin, Steve J; Sandoval, Nathan P; Fensin, Mike L

    2010-01-01

    For the purpose of measuring plutonium mass in spent fuel, a delayed neutron instrument is of particular interest since, if properly designed, the delayed neutron signal from {sup 235}U is significantly stronger than the signature from {sup 239}Pu or {sup 241}Pu. A key factor in properly designing a delayed neutron instrument is to minimize the fission of {sup 238}U. This minimization is achieved by keeping the interrogating neutron spectrum below {approx} 1 MeV. In the context of spent fuel measurements it is desirable to use a 14 MeV (deuterium and tritium) neutron generator for economic reasons. Spectrum tailoring is the term used to describe the inclusion of material between the 14 MeV neutrons and the interrogated object that lower the neutron energy through nuclear reactions and moderation. This report quantifies the utility of different material combination for spectrum tailoring.

  7. Automatic methods for the adjustment of faceted solar-energy concentrators and heliostats

    NASA Astrophysics Data System (ADS)

    Zakhidov, R. A.; Khakimov, R. A.; Abdurakhmanov, A. A.; Sizov, Iu. M.; Baranov, V. K.

    An automatic adjustment technique is described which makes possible a considerable simplification of the operation of solar-energy installations. Diagrams of devices for the automatic adjustment of the facets of a composite concentrator and of a plane heliostat are presented. An error analysis shows that the accuracy of the adjustment method is 4-5 arcmin.

  8. The Spatial Energy Spectrum of Magnetic Fields in Our Galaxy

    NASA Astrophysics Data System (ADS)

    Han, J. L.; Ferriere, K.; Manchester, R. N.

    2004-08-01

    Interstellar magnetic fields exist over a broad range of spatial scales, extending from large Galactic scales (~10 kpc) down to very small dissipative scales (<<1 pc). In this paper, we use a set of 490 pulsars distributed over roughly one-third of the Galactic disk out to a radius R~=10 kpc (assuming Rsolar=8.5 kpc) and combine their observed rotation and dispersion measures with their estimated distances to derive the spatial energy spectrum of the Galactic interstellar magnetic field over the scale range 0.5-15 kpc. We obtain a nearly flat spectrum, with a one-dimensional power-law index α=-0.37+/-0.10 for EB(k)=Ckα and an rms field strength of approximately 6 μG over the relevant scales. Our study complements the derivation of the magnetic energy spectrum over the scale range 0.03-100 pc by Minter & Spangler, showing that the magnetic spectrum becomes flatter at larger scales. This observational result is discussed in the framework of current theoretical and numerical models.

  9. Development of a continuous broad-energy-spectrum electron source

    NASA Technical Reports Server (NTRS)

    Adamo, R. C.; Nanevicz, J. E.

    1985-01-01

    The development of a practical prototype, large-area, continuous-spectrum, multienergy electron source to simulate the lower energy (approx = 1 to 30 keV) portion of the geosynchronous orbit electron environment was investigated. The results of future materials-charging tests using this multienergy source should significantly improve the understanding of actual in-orbit charging processes and should help to resolve some of the descrepancies between predicted and observed spacecraft materials performance.

  10. Exact ultra cold neutrons' energy spectrum in gravitational quantum mechanics

    NASA Astrophysics Data System (ADS)

    Pedram, Pouria

    2013-10-01

    We find exact energy eigenvalues and eigenfunctions of the quantum bouncer in the presence of the minimal length uncertainty and the maximal momentum. This form of Generalized (Gravitational) Uncertainty Principle (GUP) agrees with various theories of quantum gravity and predicts a minimal length uncertainty proportional to and a maximal momentum proportional to , where β is the deformation parameter. We also find the semiclassical energy spectrum and discuss the effects of this GUP on the transition rate of the ultra cold neutrons in gravitational spectrometers. Then, based on Nesvizhevsky's famous experiment, we obtain an upper bound on the dimensionless GUP parameter.

  11. XTE Proposal #20102--"SS 433's High Energy Spectrum"

    NASA Technical Reports Server (NTRS)

    Band, David L.; Blanco, P.; Rothschild, R.; Kawai, N.; Kotani, T.; Oka, T.; Wagner, R. M.; Hjellming, R.; Rupen, M.; Brinkmann, W.

    1999-01-01

    We observed the jet-producing compact binary system SS 433 with RXTE during three multiwavelength campaigns, the first in conjunction with ASCA observations, the second simultaneous with a VLA-VLBA-MERLIN campaign, and the third associated with a Nobeyama millimeter-band campaign. All these campaigns included optical observations. Occurring at different jet precession and binary phases, the observations also monitored the system during a radio flare. The data provide SS 433's X-ray spectrum over more than an energy decade, and track the spectral variations as the X-ray source was partially eclipsed. The continuum can be modeled as a power law with an exponential cutoff, which can be detected to approximately 50 keV. Strong line emission is evident in the 5-10 keV range which can be modeled as a broad line whose energy is precession independent and a narrow line whose energy does vary with jet precession phase; this line model is clearly an over simplification since the PCA does not have sufficient energy resolution to detect the lines ASCA observed. The eclipses are deeper at high energy and at jet precession phases when the jets are more inclined towards and away from us. A large radio flare occurred between two sets of X-ray monitoring observations; an X-ray observation at the peak of the flare found a softer spectrum with a flux approximately 1/3 that of the quiescent level.

  12. Model-based x-ray energy spectrum estimation algorithm from CT scanning data with spectrum filter

    NASA Astrophysics Data System (ADS)

    Li, Lei; Wang, Lin-Yuan; Yan, Bin

    2016-10-01

    With the development of technology, the traditional X-ray CT can't meet the modern medical and industry needs for component distinguish and identification. This is due to the inconsistency of X-ray imaging system and reconstruction algorithm. In the current CT systems, X-ray spectrum produced by X-ray source is continuous in energy range determined by tube voltage and energy filter, and the attenuation coefficient of object is varied with the X-ray energy. So the distribution of X-ray energy spectrum plays an important role for beam-hardening correction, dual energy CT image reconstruction or dose calculation. However, due to high ill-condition and ill-posed feature of system equations of transmission measurement data, statistical fluctuations of X ray quantum and noise pollution, it is very hard to get stable and accurate spectrum estimation using existing methods. In this paper, a model-based X-ray energy spectrum estimation method from CT scanning data with energy spectrum filter is proposed. First, transmission measurement data were accurately acquired by CT scan and measurement using phantoms with different energy spectrum filter. Second, a physical meaningful X-ray tube spectrum model was established with weighted gaussian functions and priori information such as continuity of bremsstrahlung and specificity of characteristic emission and estimation information of average attenuation coefficient. The parameter in model was optimized to get the best estimation result for filtered spectrum. Finally, the original energy spectrum was reconstructed from filtered spectrum estimation with filter priori information. Experimental results demonstrate that the stability and accuracy of X ray energy spectrum estimation using the proposed method are improved significantly.

  13. Sharp knee phenomenon of primary cosmic ray energy spectrum

    NASA Astrophysics Data System (ADS)

    Ter-Antonyan, Samvel

    2014-06-01

    Primary energy spectral models are tested in the energy range of 1-200 PeV using standardized extensive air shower responses from BASJE-MAS, Tibet, GAMMA and KASCADE scintillation shower arrays. Results point toward the two-component origin of observed cosmic ray energy spectra in the knee region consisting of a pulsar component superimposed upon rigidity-dependent power law diffuse Galactic flux. The two-component energy spectral model accounts for both the sharp knee shower spectral phenomenon and observed irregularity of all-particle energy spectrum in the region of 50-100 PeV. Alternatively, tested multipopulation primary energy spectra predicted by nonlinear diffusive shock acceleration models describe observed shower spectra in the knee region provided that the cutoff magnetic rigidities of accelerating particles are 6±0.3 and 45±2 PV for the first two populations, respectively. Both tested spectral models confirm the predominant H-He primary nuclei origin of observed shower spectral knee. The parameters of tested energy spectra are evaluated using solutions of the inverse problem on the basis of the corresponding parameterizations of energy spectra for primary H, He, O-like and Fe-like nuclei, standardized shower size spectral responses in the 550-1085 g/cm2 atmospheric slant depth range and near vertical muon truncated size spectra detected by the GAMMA array.

  14. Energy spectrum of sputtered uranium - A new technique

    NASA Technical Reports Server (NTRS)

    Weller, R. A.; Tombrello, T. A.

    1978-01-01

    The fission track technique for detecting U-235 has been used in conjunction with a mechanical time-of-flight spectrometer in order to measure the energy spectrum in the region 1 eV to 1 keV of material sputtered from a 93% enriched U-235 foil by 80 keV Ar-40(+) ions. The spectrum was found to exhibit a peak in the region 2-4 eV and to decrease approximately as E exp -1.77 for E not less than 100 eV. The design, construction and resolution of the mechanical spectrometer are discussed and comparisons are made between the data and the predictions of the random collision cascade model of sputtering.

  15. Search for the end of the cosmic ray energy spectrum

    SciTech Connect

    Linsley, John

    1998-06-15

    The title I was asked to speak about expresses an idea that occurred rather recently in the history of cosmic ray studies. I argue that the idea of a possible end of the cosmic ray energy spectrum came into being after a sequence of three rapid advances in knowledge which I describe, calling them 'breakthroughs'. I suggest that the present workshop be regarded as a step toward a fourth breakthrough. I argue that this may occur through application of the Space Airwatch concept--the earth atmosphere as target and signal generator--as embodied in the NASA OWL project.

  16. Psychosocial Adjustment and Sibling Relationships in Siblings of Children with Autism Spectrum Disorder: Risk and Protective Factors.

    PubMed

    Walton, Katherine M; Ingersoll, Brooke R

    2015-09-01

    This study compared sibling adjustment and relationships in siblings of children with Autism Spectrum Disorder (ASD-Sibs; n = 69) and siblings of children with typical development (TD-Sibs; n = 93). ASD-Sibs and TD-Sibs demonstrated similar emotional/behavioral adjustment. Older male ASD-Sibs were at increased risk for difficulties. Sibling relationships of ASD-Sibs involved less aggression, less involvement, and more avoidance than those of TD-Sibs. Partial support for a diathesis-stress conceptualization of sibling difficulties was found for ASD-Sibs. For TD-Sibs, broader autism phenotype (BAP) was related to psychosocial difficulties regardless of family stressors. For ASD-Sibs, BAP was related to difficulties only when family stressors were present. This suggests that having a sibling with ASD may be a protective factor that attenuates the negative impact of sibling BAP.

  17. Low energy photon mimic of the tritium beta decay energy spectrum

    NASA Astrophysics Data System (ADS)

    Malabre-O'Sullivan, Neville

    Tritium is a radioactive hydrogen isotope that is typically produced via neutron interaction with heavy water (D2O), producing tritiated water (DTO). As a result of this, tritium accounts for roughly a third of all occupational exposures at a CANDU type nuclear power plant. This identifies a need to study the biological effects associated with tritium (and low energy electrons in general). However, there are complications regarding the dosimetry of tritium, as well as difficulties in handling and using tritium for the purposes of biophysics experiments. To avoid these difficulties, an experiment has been proposed using photons to mimic the beta decay energy spectrum of tritium. This would allow simulation of the radiation properties of tritium, so that a surrogate photon source can be used for biophysics experiments. Through experimental and computational means, this work has explored the use of characteristic x-rays of various materials to modify the output spectrum of an x-ray source, such that it mimics the tritium beta decay spectrum. Additionally, the resultant primary electron spectrum generated in water from an x-ray source was simulated. The results from this research have indicated that the use of characteristic x-rays is not a viable method for simulating a tritium source. Also, the primary electron spectrum generated in water shows some promise for simulating tritium exposure, however further work must be done to investigate the slowing down electron spectrum. Keywords: Tritium, MCNP, low energy electrons, biophysics, characteristic x-rays.

  18. Energy spectrum of oscillations in generalized Sagdeev potential

    NASA Astrophysics Data System (ADS)

    Akbari-Moghanjoughi, M.

    2017-07-01

    In this paper, the full energy spectrum of nonlinear oscillations, known as the cnoidal waves, is studied in the framework of small-amplitude Korteweg de Vries and modified Korteweg de Vries (mKdV) theories based on the pseudoparticle motion in Helmholtz and Duffing potentials by employing the newly introduced pseudoenergy concept. The pseudoenergy dependence of various cnoidal oscillation parameters is then studied, and it is shown that superposition of cnoidal waves leads to familiar beating and Lissajous profiles. One of the most important aspects of the nonlinear oscillation is found to be the frequency dependence of the oscillation amplitude which mainly characterizes the nature of oscillations. It is shown that the developed method can be used to study the spectrum of oscillations and shock waves in the fully nonlinear Sagdeev pseudopotential and to directly calculate many dynamic parameters of the given nonlinear system. Current research may be helpful in understanding of basic excitations and interaction of nonlinear oscillation in various hydrodynamic systems including plasmas. It is also shown that nonlinear excitations in a hydrodynamic fluid can be effectively investigated by close inspection of shock waves which contain the full nonlinear spectrum of dynamical systems.

  19. Network characteristics, perceived social support, and psychological adjustment in mothers of children with autism spectrum disorder.

    PubMed

    Benson, Paul R

    2012-12-01

    This study examined the characteristics of the support networks of 106 mothers of children with ASD and their relationship to perceived social support, depressed mood, and subjective well-being. Using structural equation modeling, two competing sets of hypotheses were assessed: (1) that network characteristics would impact psychological adjustment directly, and (2) that network effects on adjustment would be indirect, mediated by perceived social support. Results primarily lent support to the latter hypotheses, with measures of network structure (network size) and function (proportion of network members providing emotional support) predicting increased levels of perceived social support which, in turn, predicted decreased depressed mood and increased well-being. Results also indicated that increased interpersonal strain in the maternal network was directly and indirectly associated with increased maternal depression, while being indirectly linked to reduced well-being. Study limitations and implications are discussed.

  20. Cosmic-ray positron energy spectrum measured by PAMELA.

    PubMed

    Adriani, O; Barbarino, G C; Bazilevskaya, G A; Bellotti, R; Bianco, A; Boezio, M; Bogomolov, E A; Bongi, M; Bonvicini, V; Bottai, S; Bruno, A; Cafagna, F; Campana, D; Carbone, R; Carlson, P; Casolino, M; Castellini, G; De Donato, C; De Santis, C; De Simone, N; Di Felice, V; Formato, V; Galper, A M; Karelin, A V; Koldashov, S V; Koldobskiy, S A; Krutkov, S Y; Kvashnin, A N; Leonov, A; Malakhov, V; Marcelli, L; Martucci, M; Mayorov, A G; Menn, W; Mergé, M; Mikhailov, V V; Mocchiutti, E; Monaco, A; Mori, N; Munini, R; Osteria, G; Palma, F; Papini, P; Pearce, M; Picozza, P; Pizzolotto, C; Ricci, M; Ricciarini, S B; Rossetto, L; Sarkar, R; Scotti, V; Simon, M; Sparvoli, R; Spillantini, P; Stochaj, S J; Stockton, J C; Stozhkov, Y I; Vacchi, A; Vannuccini, E; Vasilyev, G I; Voronov, S A; Yurkin, Y T; Zampa, G; Zampa, N; Zverev, V G

    2013-08-23

    Precision measurements of the positron component in the cosmic radiation provide important information about the propagation of cosmic rays and the nature of particle sources in our Galaxy. The satellite-borne experiment PAMELA has been used to make a new measurement of the cosmic-ray positron flux and fraction that extends previously published measurements up to 300 GeV in kinetic energy. The combined measurements of the cosmic-ray positron energy spectrum and fraction provide a unique tool to constrain interpretation models. During the recent solar minimum activity period from July 2006 to December 2009, approximately 24,500 positrons were observed. The results cannot be easily reconciled with purely secondary production, and additional sources of either astrophysical or exotic origin may be required.

  1. The energy spectrum and the optical absorption spectrum of C{sub 60} fullerene within the Hubbard model

    SciTech Connect

    Silant’ev, A. V.

    2015-10-15

    Anticommutator Green’s functions and the energy spectrum of C{sub 60} fullerene are calculated in the approximation of static fluctuations within the Hubbard model. On the basis of this spectrum, an interpretation is proposed for the experimentally observed optical absorption bands of C{sub 60} fullerene. The parameters of C{sub 60} fullerene that characterize it within the Hubbard model are calculated by the optical absorption spectrum.

  2. Sensitivity of EAS measurements to the energy spectrum of muons

    NASA Astrophysics Data System (ADS)

    Espadanal, J.; Cazon, L.; Conceição, R.

    2017-01-01

    We have studied how the energy spectrum of muons at production affects some of the most common measurements related to muons in extensive air shower studies, namely, the number of muons at the ground, the slope of the lateral distribution of muons, the apparent muon production depth, and the arrival time delay of muons at ground. We found that by changing the energy spectrum by an amount consistent with the difference between current models (namely EPOS-LHC and QGSJET-II.04), the muon surface density at ground increases 5% at 20° zenith angle and 17% at 60° zenith angle. This effect introduces a zenith angle dependence on the reconstructed number of muons which might be experimentally observed. The maximum of the muon production depth distribution at 40° increases ∼ 10 g/cm2 and ∼ 0 g/cm2 at 60°, which, from pure geometrical considerations, increases the arrival time delay of muons. There is an extra contribution to the delay due to the subluminal velocities of muons of the order of ∼ 3 ns at all zenith angles. Finally, changes introduced in the logarithmic slope of the lateral density function are less than 2%.

  3. Measurement of neutron energy spectrum at the radial channel No. 4 of the Dalat reactor.

    PubMed

    Son, Pham Ngoc; Tan, Vuong Huu

    2016-01-01

    Several compositions of neutron filters have been installed at the channel No. 4 of the Dalat research reactor to produce quasi-monoenergetic neutron beams. However, this neutron facility has been proposed to enhance the quality of the experimental instruments, and to characterize the neutron spectrum parameters for new filtered neutron beams of 2 keV, 24 keV, 59 keV and 133 keV. In order to meet the demand of neutron spectrum information for calculation and design of filtered neutron facilities at the Dalat nuclear research reactor (DNRR), the experimental determinations of neutron flux and energy spectrum, up to 8 MeV, has been performed at the inner entrance of the horizontal channel No. 4 from the core of DNRR. The Westcott neutron fluxes as well as the α-parameter that represents the deviation of epithermal neutron distribution from the 1/E law were measured by applying the cadmium ratio and the multi-foils activation methods. The fast neutron spectrum was measured based on the iterative adjustment procedure with threshold reactions. A set of pure metal thin foils with the diameter of 1.27 cm and thickness of 0.125 mm were used as threshold detectors to measure the integrated fluxes, and a calculation procedure on iterative adjustment was implemented to derive the differential neutron energy spectrum from the integrated values. The neutron fluxes and spectrum parameters were characterized with the measured values of 4.80 × 10(9), 1.98 × 10(7), 5.06 × 10(8) cm(-2) s(-1) and 0.0448 for the thermal, epithermal, fast neutron fluxes and the α-shape factor, respectively. The present result has been significantly applied to the input data for the Monte Carlo simulations in the developments of filtered mono-energetic neutron beam facility at the institute.

  4. DSM-5 PTSD and posttraumatic stress spectrum in Italian emergency personnel: correlations with work and social adjustment

    PubMed Central

    Carmassi, Claudia; Gesi, Camilla; Simoncini, Marly; Favilla, Luca; Massimetti, Gabriele; Olivieri, Maria Cristina; Conversano, Ciro; Santini, Massimo; Dell’Osso, Liliana

    2016-01-01

    The Diagnostic and Statistical Manual of Mental Disorders Fifth Edition (DSM-5) has recently recognized a particular risk for posttraumatic stress disorder (PTSD) among first responders (criterion A4), acknowledging emergency units as stressful places of employment. Little data is yet available on DSM-5 among emergency health operators. The aim of this study was to assess DSM-5 symptomatological PTSD and posttraumatic stress spectrum, as well as their impact on work and social functioning, in the emergency staff of a major university hospital in Italy. One hundred and ten subjects (doctors, nurses, and health-care assistants) were recruited at the Emergency Unit of the Azienda Ospedaliero-Universitaria Pisana (Italy) and assessed by the Trauma and Loss Spectrum-Self Report (TALS-SR) and Work and Social Adjustment Scale (WSAS). A 15.7% DSM-5 symptomatological PTSD prevalence rate was found. Nongraduated persons reported significantly higher TALS-SR Domain IV (reaction to loss or traumatic events) scores and a significantly higher proportion of individuals presenting at least one maladaptive behavior (TALS-SR Domain VII), with respect to graduate ones. Women reported significantly higher WSAS scores. Significant correlations emerged between PTSD symptoms and WSAS total scores among health-care assistants, nongraduates and women. Our results showed emergency workers to be at risk for posttraumatic stress spectrum and related work and social impairment, particularly among women and nongraduated subjects. PMID:26937192

  5. Feeling Good, Feeling Bad: Influences of Maternal Perceptions of the Child and Marital Adjustment on Well-Being in Mothers of Children with an Autism Spectrum Disorder

    ERIC Educational Resources Information Center

    Lickenbrock, Diane M.; Ekas, Naomi V.; Whitman, Thomas L.

    2011-01-01

    Mothers of children with an autism spectrum disorder (n = 49) participated in a 30-day diary study which examined associations between mothers' positive and negative perceptions of their children, marital adjustment, and maternal well-being. Hierarchical linear modeling results revealed that marital adjustment mediated associations between…

  6. Energy spectrum of thermal counterflow turbulence in superfluid helium-4

    NASA Astrophysics Data System (ADS)

    Gao, J.; Varga, E.; Guo, W.; Vinen, W. F.

    2017-09-01

    Recent preliminary experiments [A. Marakov et al., Phys. Rev. B 91, 094503 (2015)., 10.1103/PhysRevB.91.094503] using triplet-state He2 excimer molecules as tracers of the motion of the normal fluid have shown that, in thermal counterflow turbulence in superfluid 4He, small-scale turbulence in the superfluid component is accompanied, above a critical heat flux, by partially coupled large-scale turbulence in both fluids, with an energy spectrum proportional to k-m, where m is greater than the Kolmogorov value of 5/3. Here we report the results of a more detailed study of this spectrum over a range of temperatures and heat fluxes using the same experimental technique. We show that the exponent m varies systematically with heat flux but is always greater than 5/3. We interpret this as arising from the steady counterflow, which causes large-scale eddies in the two fluids to be pulled in opposite directions, giving rise to dissipation by mutual friction at all wave numbers, mutual friction tending also to oppose the effect of the counterflow. Comparison of the experimental results with a simple theory suggests that this process may be more complicated than we might have hoped, but experiments covering a wider range of heat fluxes, which are technically very difficult, will probably be required before we can arrive at a convincing theory.

  7. Spectrum of Quantized Energy for a Lengthening Pendulum

    SciTech Connect

    Choi, Jeong Ryeol; Song, Ji Nny; Hong, Seong Ju

    2010-09-30

    We considered a quantum system of simple pendulum whose length of string is increasing at a steady rate. Since the string length is represented as a time function, this system is described by a time-dependent Hamiltonian. The invariant operator method is very useful in solving the quantum solutions of time-dependent Hamiltonian systems like this. The invariant operator of the system is represented in terms of the lowering operator a(t) and the raising operator a{sup {dagger}}(t). The Schroedinger solutions {psi}{sub n}({theta}, t) whose spectrum is discrete are obtained by means of the invariant operator. The expectation value of the Hamiltonian in the {psi}{sub n}({theta}, t) state is the same as the quantum energy. At first, we considered only {theta}{sup 2} term in the Hamiltonian in order to evaluate the quantized energy. The numerical study for quantum energy correction is also made by considering the angle variable not only up to {theta}{sup 4} term but also up to {theta}{sup 6} term in the Hamiltonian, using the perturbation theory.

  8. Possible dark energy imprints in the gravitational wave spectrum of mixed neutron-dark-energy stars

    SciTech Connect

    Yazadjiev, Stoytcho S.; Doneva, Daniela D. E-mail: daniela.doneva@uni-tuebingen.de

    2012-03-01

    In the present paper we study the oscillation spectrum of neutron stars containing both ordinary matter and dark energy in different proportions. Within the model we consider, the equilibrium configurations are numerically constructed and the results show that the properties of the mixed neuron-dark-energy star can differ significantly when the amount of dark energy in the stars is varied. The oscillations of the mixed neuron-dark-energy stars are studied in the Cowling approximation. As a result we find that the frequencies of the fundamental mode and the higher overtones are strongly affected by the dark energy content. This can be used in the future to detect the presence of dark energy in the neutron stars and to constrain the dark-energy models.

  9. Primary cosmic ray energy spectrum in terms of the GAMMA muon data

    NASA Astrophysics Data System (ADS)

    Garyaka, A. P.; Martirosov, R. M.; Ter-Antonyan, S. V.; Erlykin, A. D.; Nikolskaya, N. M.; Gallant, Y. A.; Jones, L. W.; Procureur, J.

    2009-12-01

    The energy spectrum of the primary cosmic rays is obtained by conversion from the truncated muon size spectrum of EAS studied with the GAMMA array. The previously observed dependence of E on Nμtr at various zenith angles is used. It is shown that the present spectrum has the same structure (“bump”) as the spectrum determined by another independent multi-parametric energy estimation method confirming that the “bump” structure is not produced by uncertainties in our methods.

  10. Effects of energy spectrum on dose distribution calculations for high energy electron beams.

    PubMed

    Toutaoui, Abdelkader; Khelassi-Toutaoui, Nadia; Brahimi, Zakia; Chami, Ahmed Chafik

    2009-01-01

    In an early work we have demonstrated the possibility of using Monte Carlo generated pencil beams for 3D electron beam dose calculations. However, in this model the electron beam was considered as monoenergetic and the effects of the energy spectrum were taken into account by correction factors, derived from measuring central-axis depth dose curves. In the present model, the electron beam is considered as polyenergetic and the pencil beam distribution of a clinical electron beam, of a given nominal energy, is represented as a linear combination of Monte Carlo monoenergetic pencil beams. The coefficients of the linear combination describe the energy spectrum of the clinical electron beam, and are chosen to provide the best-fit between the calculated and measured central axis depth dose, in water. The energy spectrum is determined by the constrained least square method. The angular distribution of the clinical electron beam is determined by in-air penumbra measurements. The predictions of this algorithm agree very well with the measurements in the region near the surface, and the discrepancies between the measured and calculated dose distributions, behind 3D heterogeneities, are reduced to less than 10%. We have demonstrated a new algorithm for 3D electron beam dose calculations, which takes into account the energy spectra. Results indicate that the use of this algorithm leads to a better modeling of dose distributions downstream, from complex heterogeneities.

  11. Effects of energy spectrum on dose distribution calculations for high energy electron beams

    PubMed Central

    Toutaoui, Abdelkader; Khelassi-Toutaoui, Nadia; Brahimi, Zakia; Chami, Ahmed Chafik

    2009-01-01

    In an early work we have demonstrated the possibility of using Monte Carlo generated pencil beams for 3D electron beam dose calculations. However, in this model the electron beam was considered as monoenergetic and the effects of the energy spectrum were taken into account by correction factors, derived from measuring central-axis depth dose curves. In the present model, the electron beam is considered as polyenergetic and the pencil beam distribution of a clinical electron beam, of a given nominal energy, is represented as a linear combination of Monte Carlo monoenergetic pencil beams. The coefficients of the linear combination describe the energy spectrum of the clinical electron beam, and are chosen to provide the best-fit between the calculated and measured central axis depth dose, in water. The energy spectrum is determined by the constrained least square method. The angular distribution of the clinical electron beam is determined by in-air penumbra measurements. The predictions of this algorithm agree very well with the measurements in the region near the surface, and the discrepancies between the measured and calculated dose distributions, behind 3D heterogeneities, are reduced to less than 10%. We have demonstrated a new algorithm for 3D electron beam dose calculations, which takes into account the energy spectra. Results indicate that the use of this algorithm leads to a better modeling of dose distributions downstream, from complex heterogeneities. PMID:20126560

  12. Ultra high energy events in ECHOS series and primary energy spectrum

    NASA Technical Reports Server (NTRS)

    Capdevielle, J. N.; Iwai, J.; Ogata, T.

    1985-01-01

    The compilation of ultra high energy jets suggests at present the existence of a bump in primary energy spectrum (with the standard concept of high energy collisions). The pseudo-rapidity distribution exhibits some typical anomalies, more than the (P sub t) behavior, which are (may be) the fingerprints of quark gluon plasma transition. The next results of Emulsion Chamber on Supersonic (ECHOS) will be in both cases determinant to confirm those tendancies, as well as an important effort of the cosmic ray community to develop in that sense a flying emulsion chamber experiment.

  13. 77 FR 24192 - Energy Spectrum, Inc. and Riverbay Corporation v. New York Independent System Operator; Notice of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-23

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Energy Spectrum, Inc. and Riverbay Corporation v. New York Independent... Commission (Commission), 18 CFR 385.206, Energy Spectrum, Inc. and Riverbay Corporation...

  14. An all-particle primary energy spectrum in the 3 200 PeV energy range

    NASA Astrophysics Data System (ADS)

    Garyaka, A. P.; Martirosov, R. M.; Ter-Antonyan, S. V.; Erlykin, A. D.; Nikolskaya, N. M.; Gallant, Y. A.; Jones, L. W.; Procureur, J.

    2008-11-01

    We present an all-particle primary cosmic-ray energy spectrum in the 3 × 106-2 × 108 GeV energy range obtained by a multi-parametric event-by-event evaluation of the primary energy. The results are obtained on the basis of an expanded EAS data set detected at mountain level (700 g cm-2) by the GAMMA experiment. The energy evaluation method has been developed using the EAS simulation with the SIBYLL interaction model taking into account the response of GAMMA detectors and reconstruction uncertainties of EAS parameters. Nearly unbiased (<5%) energy estimations regardless of a primary nuclear mass with an accuracy of about 15-10% in the 3 × 106-2 × 108 GeV energy range respectively are attained. An irregularity ('bump') in the spectrum is observed at primary energies of ~7.4 × 107 GeV. This bump exceeds a smooth power-law fit to the data by about 4 standard deviations. By not rejecting the stochastic nature of the bump completely, we examined the systematic uncertainties of our methods and conclude that they cannot be responsible for the observed feature.

  15. Chandra High-Energy Transmission Grating Spectrum of AE Aquarii

    NASA Astrophysics Data System (ADS)

    Mauche, Christopher W.

    2009-11-01

    The nova-like cataclysmic binary AE Aqr, which is currently understood to be a former supersoft X-ray binary and current magnetic propeller, was observed for over two binary orbits (78 ks) in 2005 August with the High-Energy Transmission Grating (HETG) on board the Chandra X-ray Observatory. The long, uninterrupted Chandra observation provides a wealth of details concerning the X-ray emission of AE Aqr, many of which are new and unique to the HETG. First, the X-ray spectrum is that of an optically thin multi-temperature thermal plasma; the X-ray emission lines are broad, with widths that increase with the line energy from σ ≈ 1 eV (510 km s-1) for O VIII to σ ≈ 5.5 eV (820 km s-1) for Si XIV; the X-ray spectrum is reasonably well fit by a plasma model with a Gaussian emission measure distribution that peaks at log T(K) = 7.16, has a width σ = 0.48, an Fe abundance equal to 0.44 times solar, and other metal (primarily Ne, Mg, and Si) abundances equal to 0.76 times solar; and for a distance d = 100 pc, the total emission measure EM = 8.0 × 1053 cm-3 and the 0.5-10 keV luminosity L X = 1.1 × 1031 erg s-1. Second, based on the f/(i + r) flux ratios of the forbidden (f), intercombination (i), and recombination (r) lines of the Heα triplets of N VI, O VII, and Ne IX measured by Itoh et al. in the XMM-Newton Reflection Grating Spectrometer spectrum and those of O VII, Ne IX, Mg XI, and Si XIII in the Chandra HETG spectrum, either the electron density of the plasma increases with temperature by over three orders of magnitude, from n e ≈ 6 × 1010 cm-3 for N VI [log T(K) ≈ 6] to n e ≈ 1 × 1014 cm-3 for Si XIII [log T(K) ≈ 7], and/or the plasma is significantly affected by photoexcitation. Third, the radial velocity of the X-ray emission lines varies on the white dwarf spin phase, with two oscillations per spin cycle and an amplitude K ≈ 160 km s-1. These results appear to be inconsistent with the recent models of Itoh et al., Ikhsanov, and Venter

  16. Simulation-based coefficients for adjusting climate impact on energy consumption of commercial buildings

    SciTech Connect

    Wang, Na; Makhmalbaf, Atefe; Srivastava, Viraj; Hathaway, John E.

    2016-11-23

    This paper presents a new technique for and the results of normalizing building energy consumption to enable a fair comparison among various types of buildings located near different weather stations across the U.S. The method was developed for the U.S. Building Energy Asset Score, a whole-building energy efficiency rating system focusing on building envelope, mechanical systems, and lighting systems. The Asset Score is calculated based on simulated energy use under standard operating conditions. Existing weather normalization methods such as those based on heating and cooling degrees days are not robust enough to adjust all climatic factors such as humidity and solar radiation. In this work, over 1000 sets of climate coefficients were developed to separately adjust building heating, cooling, and fan energy use at each weather station in the United States. This paper also presents a robust, standardized weather station mapping based on climate similarity rather than choosing the closest weather station. This proposed simulated-based climate adjustment was validated through testing on several hundreds of thousands of modeled buildings. Results indicated the developed climate coefficients can isolate and adjust for the impacts of local climate for asset rating.

  17. Energy spectrum measured by the telescope array surface detector

    NASA Astrophysics Data System (ADS)

    Ivanov, Dmitri

    2012-05-01

    Two conflicting measurements of the ultra high energy cosmic ray (UHECR) flux have been reported by the Akeno Giant Air Shower Array (AGASA) and the High Resolution Fly's Eye (HiRes) experiments. HiRes observes a ˜5sigma suppression at E = 1019.75 eV, which is in agreement with the prediction of Greisen-Zatsepin-Kuz'min (GZK) theory. AGASA, in contrast, sees the flux extended well beyond E = 1020 eV with no visible break, suggesting that the flux is limited only by the rate at which the sources can produce the UHECR and not by interaction of energetic particles with the cosmic microwave background, thus challenging the relativistic invariance principle. In response to this discrepancy, a new experiment named the Telescope Array (TA) has been deployed, which combines the detection elements used separately by HiRes and AGASA. We describe the TA surface detector (SD) analysis using a technique new to the field, which consists of a detailed Monte-Carlo (MC) simulation of the SD response to the natural cosmic rays, validating the MC by comparing its distributions with the data, and calculation of the SD aperture from the MC. We will also describe our reconstruction procedure, based solely upon the data, and its application to both data and the MC. Finally, we will describe the energy spectrum resulting from this analysis, which is found to be in excellent agreement with the HiRes result, and as such, is the first confirmation of the GZK effect by a ground array of scintillation counters.

  18. Charging energy spectrum of black phosphorus quantum dots

    NASA Astrophysics Data System (ADS)

    Lino, M. A.; de Sousa, J. S.; da Costa, D. R.; Chaves, A.; Pereira, J. M.; Farias, G. A.

    2017-08-01

    We present a theoretical study of the charging effects in single and double layer black phosphorus quantum dots (BPQDs) with lateral sizes of 2 nm and 3 nm. We demonstrate that the charging of BPQDs are able to store up to an N max electron (that depends on the lateral size and number of layers in the QD), after which structural instabilities arises. For example, 3 nm wide hydrogen-passivated single layer BPQDs can hold a maximum of 16 electrons, and an additional electron causes the expelling of hydrogen atoms from the QD borders. We also calculated the addition energy (E A ) spectrum. For single-layer QDs with 2 and 3 nm lateral sizes, the average E A is around 0.4 eV and 0.3 eV, respectively. For double layer QDs with the same sizes, the average E A is around 0.25 eV and 0.2 eV, respectively.

  19. Simulation of energy absorption spectrum in NaI crystal detector for multiple gamma energy using Monte Carlo method

    SciTech Connect

    Wirawan, Rahadi; Waris, Abdul; Djamal, Mitra; Handayani, Gunawan

    2015-04-16

    The spectrum of gamma energy absorption in the NaI crystal (scintillation detector) is the interaction result of gamma photon with NaI crystal, and it’s associated with the photon gamma energy incoming to the detector. Through a simulation approach, we can perform an early observation of gamma energy absorption spectrum in a scintillator crystal detector (NaI) before the experiment conducted. In this paper, we present a simulation model result of gamma energy absorption spectrum for energy 100-700 keV (i.e. 297 keV, 400 keV and 662 keV). This simulation developed based on the concept of photon beam point source distribution and photon cross section interaction with the Monte Carlo method. Our computational code has been successfully predicting the multiple energy peaks absorption spectrum, which derived from multiple photon energy sources.

  20. Chandra High Energy Transmission Grating Spectrum of AE Aquarii

    NASA Astrophysics Data System (ADS)

    Mauche, Christopher W.

    2010-03-01

    The nova-like cataclysmic binary AE Aqr was observed for over two binary orbits in 2005 August with the High-Energy Transmission Grating onboard the Chandra X-ray Observatory. The resulting spectrum is reasonably well fit by an optically thin multi-temperature thermal plasma model with a Gaussian emission measure distribution that peaks at log T (K)=7.16, has a width sigma=0.4, an Fe abundance equal to 0.44 times solar, other metal abundances equal to 0.76 times solar, an emission measure EM=8.0x1053 cm-3, and a 0.5-10 keV X-ray luminosity LX=1.1x1031 erg s-1. Based on the f/(i+r) flux ratios of the He alpha triplets of N VI, O VII, Ne IX, Mg XI, and Si XIII in the XMM-Newton RGS and Chandra HETG spectra, we find that either the electron density of the plasma increases with temperature by over three orders of magnitude, from ne 6x1010 cm-3 for N VI to ne 1x1014 cm-3 for Si XIII, and/or the plasma is significantly affected by photoexcitation. The radial velocity of the X-ray emission lines varies on the white dwarf spin phase, with two oscillations per spin cycle and an amplitude K 160 km s-1 . These results appear to be inconsistent with the recent models of Itoh et al., Ikhsanov, and Venter & Meintjes of an extended, low-density source of X-rays in AE Aqr, but instead support earlier models in which the dominant source of X-rays is of high density and/or in close proximity to the white dwarf. Support for this work was provided by NASA through Chandra Award Number GO5-6020X issued by the Chandra X-ray Observatory Center, which is operated by the Smithsonian Astrophysical Observatory for and on behalf of NASA under contract NAS8-03060. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  1. On the low energy end of the QCD spectrum

    NASA Astrophysics Data System (ADS)

    Leutwyler, H.

    2009-01-01

    The experimental results on the K and K3π decays, those on pionic atoms and recent work on the lattice confirm the predictions obtained on the basis of χPT. As a result, the energy gap of QCD is now understood very well and there is no doubt that the expansion in powers of the two lightest quark masses does represent a very useful tool for the analysis of the low energy structure. Concerning the expansion in powers of m, however, the current situation leaves much to be desired. While some of the lattice results indicate, for instance, that the violations of the Okubo-Iizuka-Zweig rule in the quark condensate and in the decay constants are rather modest, others point in the opposite direction. In view of the remarkable progress being made with the numerical simulation of light quarks, I am confident that the dust will settle soon, so that the effective coupling constants that govern the dependence of the various quantities of physical interest on m can reliably be determined, to next-to-next-to-leading order of the chiral expansion. The range of validity of χPT can be extended by means of dispersive methods. The properties of the physical states occurring in the spectrum of QCD below KK¯ threshold can reliably be investigated on this basis. In particular, as shown only rather recently, general principles of quantum field theory lead to an exact formula that expresses the mass and width of resonances in terms of observable quantities. The formula removes the ambiguities inherent in the analytic continuation from the real axis into the complex plane, which plagued previous determinations of the pole positions of broad resonances. The application to the ππ partial wave amplitude with I=ℓ=0 shows that there is a resonance in this channel, at M-i/2Γ≃441-i272 MeV: the lowest resonance of QCD carries the quantum numbers of the vacuum.

  2. A New Formula for Energy Spectrum of Sputtered Atoms Due to Low-Energy Light Ions

    NASA Astrophysics Data System (ADS)

    Kenmotsu, Takahiro; Yamamura, Yasunori; Ono, Tadayoshi; Kawamura, Takaichi

    A new formula has been derived to describe the energy spectrum of sputtered atoms from a target material bombarded by light ions. We assume that sputtered atoms bombarded by low-energy light ions are mainly primary knock-on atoms which are created by large-angle backscattered light ions. The escape processes of recoil atoms are estimated on the basis of the Falcone-Sigmund model. The new formula has the dependence on the incident energy of a projectile. We have compared the new formula with simulation results calculated with ACAT code for a Fe target material bombarded by 50eV, 100eV and 500eV D+ ions. Good agreements are found for 50eV and 100eV D+ ions.

  3. Revisiting the hardening of the cosmic ray energy spectrum at TeV energies

    NASA Astrophysics Data System (ADS)

    Thoudam, Satyendra; Hörandel, Jörg R.

    2013-11-01

    Measurements of cosmic rays by experiments such as ATIC, CREAM and PAMELA indicate a hardening of the cosmic ray energy spectrum at TeV energies. In our recent work, we showed that the hardening can be due to the effect of nearby supernova remnants. We showed it for the case of protons and helium nuclei. In this paper, we present an improved and more detailed version of our previous work, and extend our study to heavier cosmic ray species such as boron, carbon, oxygen and iron nuclei. Unlike our previous study, the present work involves a detailed calculation of the background cosmic rays and follows a consistent treatment of cosmic ray source parameters between the background and the nearby components. Moreover, we also present a detailed comparison of our results on the secondary-to-primary ratios, secondary spectra and the diffuse gamma-ray spectrum with the results expected from other existing models, which can be checked by future measurements at high energies.

  4. Very heavy solar cosmic rays: energy spectrum and implications for lunar erosion.

    PubMed

    Fleischer, R L; Hart, H R; Comstock, G M

    1971-03-26

    The energy spectrum of solar cosmic-ray particles of the iron group has been determined for the first time over the energy range from 1 to 100 million electron volts per nucleon by the use of glass removed from the Surveyor 3 spacecraft. The difference between the observed (energy)(-3) spectrum and the limiting spectrum derived previously from tracks in lunar rocks gives an erosion rate of 0 to 2 angstroms per year. High-energy fission of lead, induced by galactic cosmicray protons and alpha particles, has also been observed.

  5. Energy spectrum of interplanetary magnetic flux ropes and its connection with solar activity

    NASA Astrophysics Data System (ADS)

    Wu, D. J.; Feng, H. Q.; Chao, J. K.

    2008-03-01

    Context: Recent observations of the solar wind show that interplanetary magnetic flux ropes (IMFRs) have a continuous scale-distribution from small-scale flux ropes to large-scale magnetic clouds. Aims: In this work, we investigate the energy spectrum of IMFRs and its possible connection with solar activity. Methods: In consideration of the detectable probability of an IMFR to be proportional to its diameter, the actual energy spectrum of IMFRs can be obtained from the observed spectrum based on spacecraft observations in the solar wind. Results: It is found that IMFRs have a negative power-law spectrum with an index α = 1.36±0.03, which is similar to that of solar flares, and is probably representative of interplanetary energy spectrum of coronal mass ejections (CMEs), that is, the energy spectrum of interplanetary CMEs (ICMEs). This indicates that the energy distribution of CMEs has a similar negative power-law spectrum. In particular, there are numerous small-scale CMEs in the solar corona, and their interplanetary consequences may be directly detected in situ by spacecraft in the solar wind as small-scale IMFRs, although they are too weak to appear clearly in current coronagraph observations. Conclusions: The presence of small-scale CMEs, especially the energy spectrum of CMEs is potentially important for understanding both the solar magneto-atmosphere and CMEs.

  6. Solar and internal gain adjustments in calculation of energy conservation savings

    NASA Astrophysics Data System (ADS)

    Christensen, C.; Wortman, D.

    1983-07-01

    Heating degree days are often used as a climatic measure in building energy calculations. To account for the effects of solar and internal gains, degree days at a lower base temperature are sometimes used, or the number of degree days is adjusted downward by a degree-day correction factor. A theoretical derivation which demonstrates that ASHRAE (American Society of Heating, Refrigerating, and Air-Conditioning Engineers) C sub d factors are not the appropriate correction factors for calculation of energy savings from envelope conservation measures is presented. The results of this derivation can be used to develop new correlation factors appropriate for savings calculations.

  7. Spectrum and ionization rate of low-energy Galactic cosmic rays

    NASA Astrophysics Data System (ADS)

    Nath, Biman B.; Gupta, Nayantara; Biermann, Peter L.

    2012-09-01

    We consider the rate of ionization of diffuse and molecular clouds in the interstellar medium by Galactic cosmic rays (GCRs) in order to constrain its low-energy spectrum. We extrapolate the GCR spectrum obtained from PAMELA at high energies (≥200 GeV nucleon-1) and a recently derived GCR proton flux at 1-200 GeV from observations of gamma-rays from molecular clouds, and find that the observed average Galactic ionization rate can be reconciled with this GCR spectrum if there is a low-energy cut-off for protons at 10-100 MeV. We also identify the flattening below a few GeV as being due to (a) decrease of the diffusion coefficient and dominance of convective loss at low energy and (b) the expected break in energy spectrum for a constant spectral index in momentum. We show that the inferred CR proton spectrum of ? for Ekin≤ few GeV is consistent with a power-law spectrum in momentum p-2.45± 0.4, which we identify as the spectrum at source. Diffusion loss at higher energies then introduces a steepening by E-α with α˜ 1/3, making it consistent with high-energy measurements.

  8. Segmentation-free x-ray energy spectrum estimation for computed tomography using dual-energy material decomposition.

    PubMed

    Zhao, Wei; Xing, Lei; Zhang, Qiude; Xie, Qingguo; Niu, Tianye

    2017-04-01

    An x-ray energy spectrum plays an essential role in computed tomography (CT) imaging and related tasks. Because of the high photon flux of clinical CT scanners, most of the spectrum estimation methods are indirect and usually suffer from various limitations. In this study, we aim to provide a segmentation-free, indirect transmission measurement-based energy spectrum estimation method using dual-energy material decomposition. The general principle of this method is to minimize the quadratic error between the polychromatic forward projection and the raw projection to calibrate a set of unknown weights, which are used to express the unknown spectrum together with a set of model spectra. The polychromatic forward projection is performed using material-specific images, which are obtained using dual-energy material decomposition. The algorithm was evaluated using numerical simulations, experimental phantom data, and realistic patient data. The results show that the estimated spectrum matches the reference spectrum quite well and the method is robust. Extensive studies suggest that the method provides an accurate estimate of the CT spectrum without dedicated physical phantom and prolonged workflow. This paper may be attractive for CT dose calculation, artifacts reduction, polychromatic image reconstruction, and other spectrum-involved CT applications.

  9. Interfacial free energy adjustable phase field crystal model for homogeneous nucleation.

    PubMed

    Guo, Can; Wang, Jincheng; Wang, Zhijun; Li, Junjie; Guo, Yaolin; Huang, Yunhao

    2016-05-18

    To describe the homogeneous nucleation process, an interfacial free energy adjustable phase-field crystal model (IPFC) was proposed by reconstructing the energy functional of the original phase field crystal (PFC) methodology. Compared with the original PFC model, the additional interface term in the IPFC model effectively can adjust the magnitude of the interfacial free energy, but does not affect the equilibrium phase diagram and the interfacial energy anisotropy. The IPFC model overcame the limitation that the interfacial free energy of the original PFC model is much less than the theoretical results. Using the IPFC model, we investigated some basic issues in homogeneous nucleation. From the viewpoint of simulation, we proceeded with an in situ observation of the process of cluster fluctuation and obtained quite similar snapshots to colloidal crystallization experiments. We also counted the size distribution of crystal-like clusters and the nucleation rate. Our simulations show that the size distribution is independent of the evolution time, and the nucleation rate remains constant after a period of relaxation, which are consistent with experimental observations. The linear relation between logarithmic nucleation rate and reciprocal driving force also conforms to the steady state nucleation theory.

  10. Energy Spectrum of Ultra High Energy Cosmic Ray Showers Using Hybrid Analysis from Telescope Array

    NASA Astrophysics Data System (ADS)

    Allen, Monica; Abu-Zayyad, Tareq; Stokes, Benjamin

    2011-10-01

    The Telescope Array studies ultra high energy cosmic rays using a hybrid detector. Fluorescence telescopes measure the longitudinal development of the extensive air shower generated by a primary cosmic ray particle, while scintillator detectors measure the lateral distribution of secondary particles that hit the ground. The Middle Drum (MD) fluorescence telescope consists of 14 refurbished telescopes from the High Resolution Fly's Eye experiment (HiRes), providing a direct link back to the HiRes experiment and data. Using the scintillator detector data in conjunction with the MD data improves the geometrical reconstruction of the showers significantly, and hence, provides a more accurate reconstruction of the energy of the primary particle. The method for determining the spectrum will be described. The event selection and reconstruction process, along with the Monte Carlo simulation used for calculating the detector aperture and exposure will also be discussed. Detector resolutions and comparisons between Monte Carlo and data distributions of key variables that contribute to the aperture will be shown to validate the simulation. Finally, the resulting hybrid spectrum obtained from the Middle Drum fluorescence detector will be presented.

  11. Thermal compression waves. 2: Mass adjustment and vertical transfer of the total energy

    NASA Astrophysics Data System (ADS)

    Nicholls, Melville E.; Pielke, Roger A.

    1994-01-01

    A fully compressible model is used to simulate the mass adjustment that occurs in response to a prescribed heat source. Results illustrate the role that thermal compression waves have in this process. The vertical mass transport associated with compression waves decreases rapidly with height. Most of the mass transport occurs in the horizontal, with the vertical structure of the disturbance similar to that of a Lamb wave. The vertical transfer of total energy in a thermally driven mixed layer is also examined. It is shown that the upward transport of total energy is accomplished by a compression effect rather than by the exchange of warm and cold air by buoyant thermals. Model results are analyzed to determine budgets of total energy, mass and entropy. It is demonstrated that buoyant thermals are predominantly responsible for a transfer of entropy, rather than total energy. In the light of these results the notion of 'heat transport' in a fluid is discussed.

  12. Low-energy break in the spectrum of Galactic cosmic rays.

    PubMed

    Neronov, A; Semikoz, D V; Taylor, A M

    2012-02-03

    Measurements of the low-energy spectrum of Galactic cosmic rays (GCRs) by detectors on or near Earth are affected by solar modulation. To overcome this difficulty, we consider nearby molecular clouds as GCR detectors outside the Solar System. Using γ-ray observations of the clouds by the Fermi telescope, we derive the spectrum of GCRs in the clouds from the observed γ-ray emission spectrum. We find that the GCR spectrum has a low-energy break with the spectral slope hardening by ΔΓ=1.1±0.3 at an energy of E=9±3  GeV. Detection of a low-energy break enables a measurement of GCR energy density in the interstellar space U=0.9±0.3  eV/cm{3}.

  13. Measuring the Cosmic Ray Energy Spectrum and Composition with IceCube

    NASA Astrophysics Data System (ADS)

    Ruzybayev, B.

    We report a measurement of the all-particle cosmic ray energy spectrum with IceCube. The results of two different techniques are discussed. The first result is a measurement of the all-particle cosmic ray energy spectrum in the energy range from 1.58 PeV to 1.26 EeV using the IceTop air shower array, which is the surface component of the IceCube Neutrino Observatory at the South Pole. The second result is a measurement of both cosmic ray energy spectrum and composition using neural network techniques and the full IceCube as a 3-dimensional cosmic ray detector. The measured energy spectrum exhibits clear deviations from a single power law above the knee around 4 PeV and below 1 EeV.

  14. Weight-adjusted resting energy expenditure is not constant in critically ill patients.

    PubMed

    Zauner, Alexandra; Schneeweiss, Bruno; Kneidinger, Nikolaus; Lindner, Gregor; Zauner, Christian

    2006-03-01

    In critically ill patients, energy requirements are frequently calculated as a multiple of total body weight presuming a linear relationship between total body weight and resting energy expenditure (REE); however, it is doubtful if this estimation of energy needs should be applied to all patients, particularly to overweight patients, since adipose tissue has a low contribution to REE. This study was undertaken to test the hypothesis that REE adjusted for total body weight decreases with increasing body mass index in critically ill patients. Additionally, measured REE was compared with three predictive equations. Clinical study in a university hospital intensive care unit. One hundred critically ill patients admitted to the intensive care unit. Patients were included into four groups according to their body mass index (normal weight, pre-obese, obese, and morbidly obese). Measured REE was assessed using indirect calorimetry. Energy needs were calculated using the basal metabolic rate, the Consensus Statement of the American College of Chest Physicians (REEacs), and 25[Symbol: see text]kcal/kg of ideal body weight (REEibw). Adjusted REE was 24.8 +/- 5.5 kcal/kg in normal weight, 22.0 +/- 3.7 kcal/kg in pre-obese, 20.4 +/- 2.6 kcal/kg in obese, and 16.3 +/- 2.3 kcal/kg in morbidly obese patients (p < 0.01). Basal metabolic rate underestimated measured REE in normal weight and pre-obese patients. REEacs and REEibw over- and underestimated measured REE in overweight patients, respectively. Predictive equations were not able to estimate measured REE adequately in all the patients. Adjusted REE decreased with increasing body mass index; thus, a body mass index group-specific adaptation for the estimation of energy needs should be applied.

  15. Energy spectrum of cascades generated by muons in Baksan underground scintillation telescope

    NASA Technical Reports Server (NTRS)

    Bakatanov, V. N.; Chudakov, A. E.; Novoseltsev, Y. F.; Novoseltseva, M. V.; Achkasov, V. M.; Semenov, A. M.; Stenkin, Y. V.

    1985-01-01

    Spectrum of cascades generated by cosmic ray muons underground is presented. The mean zenith angle of the muon arrival is theta=35 deg the depth approx. 1000 hg/sq cm. In cascades energy range 700 GeV the measured spectrum is in agreement with the sea-level integral muon spectrum index gamma=3.0. Some decrease of this exponent has been found in the range 4000 Gev.

  16. Height-Adjustable Desks: Energy Expenditure, Liking, and Preference of Sitting and Standing.

    PubMed

    Roemmich, James N

    2016-10-01

    Breaking periods of sitting with standing may prevent chronic diseases and increase energy expenditure (EE). Sit-to-stand height adjustable desks may promote workplace standing, but workers have to be willing to stand for portions of the workday. For studies 1 and 2, EE was measured during word processing while sitting in a chair and while standing. Subjects scored their liking of each posture and time they would be willing to work in each posture during an 8-hour workday. Study 2 included an intervention of replacing subjects' sitting desks with a height adjustable desk. Liking of and willingness to work in each posture were measured before and after the 12-month intervention. EE was 7.5 kcal/h greater when standing than when sitting. Subjects liked sitting more than standing in study 1. In study 2, liking of postures did not differ or change across 12 months use of height adjustable desks. Perceived willingness to stand decreased from 4.5 h/d at baseline to 3.4 h/d after 12 months. Standing rather than sitting increased EE by 7.5 kcal/h. Use of a height adjustable desk for 12 months did not alter the hedonic value of standing or sitting, which is promising for long-term increases in standing.

  17. Sewerage force adjustment technology for energy conservation in vacuum sanitation systems

    NASA Astrophysics Data System (ADS)

    Guo, Zhonghua; Li, Xiaoning; Kagawa, Toshiharu

    2013-03-01

    The vacuum sanitation is the safe and sound disposal approach of human excreta under the specific environments like flights, high speed trains and submarines. However, the propulsive force of current systems is not adjustable and the energy consumption does not adapt to the real time sewerage requirement. Therefore, it is important to study the sewerage force adjustment to improve the energy efficiency. This paper proposes an energy conservation design in vacuum sanitation systems with pneumatic ejector circuits. The sewerage force is controlled by changing the systematic vacuum degree according to the amount of the excreta. In particular, the amount of the excreta is tested by liquid level sensor and mass sensor. According to the amount of the excreta, the relationship between the excreta amount and the sewerage force is studied to provide proper propulsive force. In the other aspect, to provide variable vacuum degrees for different sanitation requirements, the suction and discharge system is designed with pneumatic vacuum ejector. On the basis of the static flow-rate characteristics and the vacuum generation model, the pressure response in the ejector circuit is studied by using the static flow rate characteristics of the ejector and air status equation. The relationship is obtained between supplied compressed air and systematic vacuum degree. When the compressed air is supplied to the ejector continuously, the systematic vacuum degree increases until the vacuum degree reaches the extreme value. Therefore, the variable systematic vacuum degree is obtained by controlling the compressed air supply of the ejector. To verify the effect of energy conservation, experiments are carried out in the artificial excreta collection, and the variable vacuum-degree design saves more than 30% of the energy supply. The energy conservation is realized effectively in the new vacuum sanitation systems with good application prospect. The proposed technology provides technological

  18. The high energy X-ray spectrum of the Crab Nebula observed from OSO 8

    NASA Technical Reports Server (NTRS)

    Dolan, J. F.; Crannell, L. J.; Dennis, B. R.; Orwig, L. E.; Maurer, G. S.; Frost, K. J.

    1977-01-01

    The X-ray spectrum of the Crab Nebula was measured with the scintillation spectrometer on board the OSO-8 satellite. The total emission of the X-ray source shows no long term variability. The spectrum itself can be described by a single power law out to energies of at least 500 keV.

  19. Energy spectrum analysis of blast waves based on an improved Hilbert-Huang transform

    NASA Astrophysics Data System (ADS)

    Li, L.; Wang, F.; Shang, F.; Jia, Y.; Zhao, C.; Kong, D.

    2017-05-01

    Using the improved Hilbert-Huang transform (HHT), this paper investigates the problems of analysis and interpretation of the energy spectrum of a blast wave. It has been previously established that the energy spectrum is an effective feature by which to characterize a blast wave. In fact, the higher the energy spectra in a frequency band of a blast wave, the greater the damage to a target in the same frequency band. However, most current research focuses on analyzing wave signals in the time domain or frequency domain rather than considering the energy spectrum. We propose here an improved HHT method combined with a wavelet packet to extract the energy spectrum feature of a blast wave. When applying the HHT, the signal is first roughly decomposed into a series of intrinsic mode functions (IMFs) by empirical mode decomposition. The wavelet packet method is then performed on each IMF to eliminate noise on the energy spectrum. Second, a coefficient is introduced to remove unrelated IMFs. The energy of each instantaneous frequency can be derived through the Hilbert transform. The energy spectrum can then be obtained by adding up all the components after the wavelet packet filters and screens them through a coefficient to obtain the effective IMFs. The effectiveness of the proposed method is demonstrated by 12 groups of experimental data, and an energy attenuation model is established based on the experimental data. The improved HHT is a precise method for blast wave signal analysis. For other shock wave signals from blasting experiments, an energy frequency time distribution and energy spectrum can also be obtained through this method, allowing for more practical applications.

  20. Interface circuit with adjustable bias voltage enabling maximum power point tracking of capacitive energy harvesting devices

    NASA Astrophysics Data System (ADS)

    Wei, J.; Lefeuvre, E.; Mathias, H.; Costa, F.

    2016-12-01

    The operation analysis of a new interface circuit for electrostatic vibration energy harvesting with adjustable bias voltage is carried out in this paper. Two configurations determined by the open or closed states of an electronic switch are examined. The increase of the voltage across a biasing capacitor, occurring when the switch is open, is proved theoretically and experimentally. With the decrease of this biasing voltage which occurs naturally when the switch is closed due to imperfections of the circuit, the bias voltage can be maintained close to a target value by appropriate ON and OFF control of the switch. As the energy converted by the variable capacitor on each cycle depends on the bias voltage, this energy can be therefore accurately controlled. This feature opens up promising perspectives for optimization the power harvested by electrostatic devices. Simulation results with and without electromechanical coupling effect are presented. In experimental tests, a simple switch control enabling to stabilize the bias voltage is described.

  1. On the massless gap'' adjustment of detected energy for passive material in front of a calorimeter

    SciTech Connect

    Trost, H.J.

    1992-01-31

    I have designed a correction scheme for energy losses in passive material in front of a calorimeter based on the massless gap'' idea. I use a flexible geometry model of a calorimeter design for SDC outside of a solenoidal coil made of aluminium cylinders of adjustable thickness. The signal from the first radiation length of active calorimetry is scaled dependent on the incoming and observed energies of the shower. A reasonable recovery of the resolution of an unobstructed calorimeter is achieved using correction factors that depend only upon the total thickness of passive material. Thus a useful correction may be built into the hardware by increasing the amount of scintillator in the first radiation length of the active calorimeter. The distribution of correction factors determined event-by-event indicate that an additional dependence on the observed signal in the massless gap and total incident energy is clearly present.

  2. On the ``massless gap`` adjustment of detected energy for passive material in front of a calorimeter

    SciTech Connect

    Trost, H.J.

    1992-01-31

    I have designed a correction scheme for energy losses in passive material in front of a calorimeter based on the ``massless gap`` idea. I use a flexible geometry model of a calorimeter design for SDC outside of a solenoidal coil made of aluminium cylinders of adjustable thickness. The signal from the first radiation length of active calorimetry is scaled dependent on the incoming and observed energies of the shower. A reasonable recovery of the resolution of an unobstructed calorimeter is achieved using correction factors that depend only upon the total thickness of passive material. Thus a useful correction may be built into the hardware by increasing the amount of scintillator in the first radiation length of the active calorimeter. The distribution of correction factors determined event-by-event indicate that an additional dependence on the observed signal in the massless gap and total incident energy is clearly present.

  3. Enhancement of high-energy cosmic-ray spectrum by type-II supernovae

    NASA Technical Reports Server (NTRS)

    Takahashi, Y.; Miyaji, S.; Parnell, T. A.; Weisskopf, M. C.; Hayashi, T.

    1986-01-01

    The cosmic-ray spectrum has an intensity enhancement in the energy range 10 to the 14th to 10 to the 16th eV per nucleus. Recent observations of heavy cosmic rays in this energy range indicate that the Ca/Fe ratio may be as large as 10 times the solar value. It is suggested that pulsars in type-II supernova remnants are the origin of this component of the cosmic-ray spectrum.

  4. Energy spectrum of isomer no. 3 of C82 fullerene of C 2 symmetry

    NASA Astrophysics Data System (ADS)

    Kareev, I. E.; Bubnov, V. P.; Kotov, A. I.; Lobanov, B. V.; Murzashev, A. I.; Rumyantsev, I. A.

    2017-01-01

    The energy spectrum of C82 fullerene (isomer no. 3 of C 2 symmetry) is calculated within the Hubbard model in the approximation of static fluctuations. Based on the energy spectrum, optical absorption spectra of this isomer in neutral and anionic states with one, two, three, and four additional electrons are simulated. The calculated optical spectra in neutral and monoanionic states are compared with known experimental spectra.

  5. Energy spectrum and transport in narrow HgTe quantum wells

    SciTech Connect

    Germanenko, A. V.; Minkov, G. M.; Rut, O. E.; Sherstobitov, A. A.; Dvoretsky, S. A.; Mikhailov, N. N.

    2015-01-15

    The results of an experimental study of the transport phenomena and the hole energy spectrum of two-dimensional systems in the quantum well of HgTe zero-gap semiconductor with normal arrangement of quantum-confinement subbands are presented. An analysis of the experimental data allows us to reconstruct the carrier energy spectrum near the hole subband extrema. The results are interpreted using the standard kP model.

  6. Design and kinetic analysis of piezoelectric energy harvesters with self-adjusting resonant frequency

    NASA Astrophysics Data System (ADS)

    Yu-Jen, Wang; Tsung-Yi, Chuang; Jui-Hsin, Yu

    2017-09-01

    Vibration-based energy harvesters have been developed as power sources for wireless sensor networks. Because the vibration frequency of the environment is varied with surrounding conditions, how to design an adaptive energy harvester is a practical topic. This paper proposes a design for a piezoelectric energy harvester possessing the ability to self-adjust its resonant frequency in rotational environments. The effective length of a trapezoidal cantilever is extended by centrifugal force from a rotating wheel to vary its area moment of inertia. The analytical solution for the natural frequency of the piezoelectric energy harvester was derived from the parameter design process, which could specify a structure approaching resonance at any wheel rotating frequency. The kinetic equation and electrical damping induced by power generation were derived from a Lagrange method and a mechanical-electrical coupling model, respectively. An energy harvester with adequate parameters can generate power at a wide range of car speeds. The output power of an experimental prototype composed of piezoelectric thin films and connected to a 3.3 MΩ external resistor was approximately 70-140 μW at wheel speeds ranging from 200 to 700 RPM. These results demonstrate that the proposed piezoelectric energy harvester can be applied as a power source for the wireless tire pressure monitoring sensor.

  7. Spectrum-Based Calibration Method for Energy Discriminating CZT Detectors Using Commercial X-Ray Generators

    NASA Astrophysics Data System (ADS)

    Xing, Xiaoman; Xu, Pin; Chen, Shi; Yuan, Gang; Mo, Jingqing; Sun, Mingshan

    2017-05-01

    Cadmium zinc telluride array detectors are known to have large pixel-to-pixel heterogeneity, which is undesirable in spectral computed tomography, and is hard to be theoretically modeled. To get better image quality and reduce the ring artifact, spectral calibration has to be done for each pixel to get uniform energy responses. Traditionally, multiple radionuclides with known characteristic emission peaks are used to calibrate the detectors. Heterogeneity of pixel responses can be compensated by electronically adjusting the gain and offset. This method is straightforward and simple, but radionuclides may not be readily available to many laboratories. In this paper, we present a method to calibrate the spectral response of each pixel with the broad spectrum features of commercial X-ray generators. For our system, the spectral response was empirically assumed to be Gaussian. A simple recursive fitting method was used to identify the intrinsic amplification and offset properties of each pixel. Gain and offset calibration were done accordingly. This method is robust, accurate, and fast, which is potentially applicable to other detectors with adaption.

  8. Energy spectrum transfer equations of solar wind turbulence

    NASA Technical Reports Server (NTRS)

    Tu, C.-Y.

    1995-01-01

    The recent studies of transfer equations for solar wind magnetohydrodynamic (MHD) turbulence are reviewed with emphasis on the comparison with the statistical observational results. Helios and Voyager missions provide an opportunity to study the the radial evolution of the power spectrum. the cross-helicity the Alfven ratio and the minimum variance direction. Spectrum transfer equations are considered as a tool to explore the nature of this radial evolution of the fluctuations. The transfer equations are derived from incompressible MHD equations. Generally one needs to make assumptions about the nature of the fluctuations and the nature of the turbulent non-linear interactions to obtain numerical results which can be compared with the observations. Some special model results for several simple cases SUCH as for structures or strong mixing. for Alfven waves with weak turbulent interactions. and for a superposition of structures and Alfven waves. are discussed. The difference between the various approaches to derive and handle the transfer equations are also addressed. Finally some theoretical description of the compressible fluctuations are also briefly reviewed.

  9. Energy spectrum transfer equations of solar wind turbulence

    NASA Technical Reports Server (NTRS)

    Tu, C.-Y.

    1995-01-01

    The recent studies of transfer equations for solar wind magnetohydrodynamic (MHD) turbulence are reviewed with emphasis on the comparison with the statistical observational results. Helios and Voyager missions provide an opportunity to study the the radial evolution of the power spectrum. the cross-helicity the Alfven ratio and the minimum variance direction. Spectrum transfer equations are considered as a tool to explore the nature of this radial evolution of the fluctuations. The transfer equations are derived from incompressible MHD equations. Generally one needs to make assumptions about the nature of the fluctuations and the nature of the turbulent non-linear interactions to obtain numerical results which can be compared with the observations. Some special model results for several simple cases SUCH as for structures or strong mixing. for Alfven waves with weak turbulent interactions. and for a superposition of structures and Alfven waves. are discussed. The difference between the various approaches to derive and handle the transfer equations are also addressed. Finally some theoretical description of the compressible fluctuations are also briefly reviewed.

  10. Energy spectrum of ultra-high energy cosmic rays observed with the Telescope Array using a hybrid technique

    NASA Astrophysics Data System (ADS)

    Abu-Zayyad, T.; Aida, R.; Allen, M.; Anderson, R.; Azuma, R.; Barcikowski, E.; Belz, J. W.; Bergman, D. R.; Blake, S. A.; Cady, R.; Cheon, B. G.; Chiba, J.; Chikawa, M.; Cho, E. J.; Cho, W. R.; Fujii, H.; Fujii, T.; Fukuda, T.; Fukushima, M.; Hanlon, W.; Hayashi, K.; Hayashi, Y.; Hayashida, N.; Hibino, K.; Hiyama, K.; Honda, K.; Iguchi, T.; Ikeda, D.; Ikuta, K.; Inoue, N.; Ishii, T.; Ishimori, R.; Ito, H.; Ivanov, D.; Iwamoto, S.; Jui, C. C. H.; Kadota, K.; Kakimoto, F.; Kalashev, O.; Kanbe, T.; Kasahara, K.; Kawai, H.; Kawakami, S.; Kawana, S.; Kido, E.; Kim, H. B.; Kim, H. K.; Kim, J. H.; Kim, J. H.; Kitamoto, K.; Kitamura, S.; Kitamura, Y.; Kobayashi, K.; Kobayashi, Y.; Kondo, Y.; Kuramoto, K.; Kuzmin, V.; Kwon, Y. J.; Lan, J.; Lim, S. I.; Lundquist, J. P.; Machida, S.; Martens, K.; Matsuda, T.; Matsuura, T.; Matsuyama, T.; Matthews, J. N.; Minamino, M.; Miyata, K.; Murano, Y.; Myers, I.; Nagasawa, K.; Nagataki, S.; Nakamura, T.; Nam, S. W.; Nonaka, T.; Ogio, S.; Ohnishi, M.; Ohoka, H.; Oki, K.; Oku, D.; Okuda, T.; Ono, M.; Oshima, A.; Ozawa, S.; Park, I. H.; Pshirkov, M. S.; Rodriguez, D. C.; Roh, S. Y.; Rubtsov, G.; Ryu, D.; Sagawa, H.; Sakurai, N.; Sampson, A. L.; Scott, L. M.; Shah, P. D.; Shibata, F.; Shibata, T.; Shimodaira, H.; Shin, B. K.; Shin, J. I.; Shirahama, T.; Smith, J. D.; Sokolsky, P.; Springer, R. W.; Stokes, B. T.; Stratton, S. R.; Stroman, T.; Suzuki, S.; Takahashi, Y.; Takeda, M.; Taketa, A.; Takita, M.; Tameda, Y.; Tanaka, H.; Tanaka, K.; Tanaka, M.; Thomas, S. B.; Thomson, G. B.; Tinyakov, P.; Tkachev, I.; Tokuno, H.; Tomida, T.; Troitsky, S.; Tsunesada, Y.; Tsutsumi, K.; Tsuyuguchi, Y.; Uchihori, Y.; Udo, S.; Ukai, H.; Urban, F.; Vasiloff, G.; Wada, Y.; Wong, T.; Yamakawa, Y.; Yamane, R.; Yamaoka, H.; Yamazaki, K.; Yang, J.; Yoneda, Y.; Yoshida, S.; Yoshii, H.; Zhou, X.; Zollinger, R.; Zundel, Z.

    2015-02-01

    We measure the spectrum of cosmic rays with energies greater than 1018.2 eV with the fluorescence detectors (FDs) and the surface detectors (SDs) of the Telescope Array Experiment using the data taken in our first 2.3-year observation from May 27, 2008 to September 7, 2010. A hybrid air shower reconstruction technique is employed to improve accuracies in determination of arrival directions and primary energies of cosmic rays using both FD and SD data. The energy spectrum presented here is in agreement with our previously published spectra and the HiRes results.

  11. Influence of the Richtmyer-Meshkov instability on the kinetic energy spectrum.

    SciTech Connect

    Weber, Christopher R.

    2010-09-01

    The fluctuating kinetic energy spectrum in the region near the Richtmyer-Meshkov instability (RMI) is experimentally investigated using particle image velocimetry (PIV). The velocity field is measured at a high spatial resolution in the light gas to observe the effects of turbulence production and dissipation. It is found that the RMI acts as a source of turbulence production near the unstable interface, where energy is transferred from the scales of the perturbation to smaller scales until dissipation. The interface also has an effect on the kinetic energy spectrum farther away by means of the distorted reflected shock wave. The energy spectrum far from the interface initially has a higher energy content than that of similar experiments with a flat interface. These differences are quick to disappear as dissipation dominates the flow far from the interface.

  12. Recent results of the energy spectrum and mass composition from Telescope Array Fluorescence Detector

    NASA Astrophysics Data System (ADS)

    Ikeda, Daisuke

    2013-02-01

    The Telescope Array experiment is the largest hybrid detector to observe Ultra-High Energy Cosmic Rays in the northern hemisphere. The observation started in November 2007 for Fluorescence Detector (FD) and in March 2008 for Surface Detectors (SD). Here, we present the preliminary results of the energy spectrum and mass composition of the UHECRs measured by the FD and hybrid technique from the Telescope Array three year observations. The energy spectrum measured by the Middle Drum FD station, which is the refurbished HiRes-I detector is consistent with the results from HiRes. The energy spectrum with the two newly constructed FDs and SD is also in good agreement with the result from HiRes, especially for the energy scale. The mass composition study with the slant depth of the maximum shower development (Xmax) is obtained by using the stereo and hybrid analysis. The result of the mass composition is consistent with the proton prediction.

  13. Fine structure of all-particle energy spectrum in the knee region

    NASA Astrophysics Data System (ADS)

    Garyaka, A.; Martirosov, R.; Ter-Antonyan, S.; Babayan, H.; Erlykin, A.; Gallant, Y.; Jones, L.; Kempa, J.; Nikolskaya, N.; Pattison, B.; Procureur, J.; Sokhoyan, S.; Vardanyan, H.

    2013-02-01

    All-particle energy spectrum in the knee region obtained from extensive air shower (EAS) measurements (GAMMA experiment, 700 g/cm2, Armenia) is presented. Energies of primary particles in the range of 106-108 GeV were evaluated on the basis of observed shower parameters Nch,Nμ, s, θ and corresponding parameterisation of CORSIKA simulated database for SIBYLL interaction model. All shower detection and reconstruction uncertainties were included in the simulated showers for four kinds (H, He, O, Fe) of primary nuclei. The reliability of observed all-particle energy spectrum is investigated from viewpoint of methodical errors and statistical fluctuations. Observed fine structure of all-particle energy spectrum can be interpreted by the rigidity-dependent steepening Galactic diffuse nuclei flux and an additional iron component in the region of 70-80 PeV primary energies most likely originated from nearby pulsars.

  14. Particle Energy Spectrum, Revisited from a Counting Statistics Perspective

    SciTech Connect

    2012-07-28

    In nuclear science, gamma and neutron spectra are counted energy by energy, and then particle by particle. Until recently, few studies have been performed on how exactly those energy spectra are counted, or how those counts are correlated. Because of lack of investigation, cross section covariance and correlation matrices are usually estimated using perturbation method. We will discuss a statistical counting scheme that shall mimic the gamma and neutron counting process used in nuclear science. From this counting scheme, the cross section covariance and correlation can be statistically derived.

  15. Adjustable Nonlinear Mechanism System for Wideband Energy Harvesting in Rotational Circumstances

    NASA Astrophysics Data System (ADS)

    Zhang, Y.; Nakano, K.; Zheng, R.; Cartmell, M. P.

    2016-09-01

    Nonlinear energy harvesters have already been exhibited to draw energy from ambient vibration owing to their particular dynamic characteristics, and are feasible to desirable responses for broadband excitations of bistable and monostable systems. This study proposes an energy harvester for rotational applications, in which a cantilever beam pasted piezoelectric film and magnets with the same polarity are comprised as a nonlinear vibrating system. As the rotationally angular velocity gradually increases, the tensile stress to the cantilever beam is also self-adjusted with the increscent centrifugal force, causing the potential barriers of bistable type become shallow, so that the cantilever beam has the ability to maintain the high energy orbit motion from bistable hardening type to monostable hardening behavior. From the implemented results, the valid bandwidth of angular frequency can be improved from 26 rad/s - 132 rad/s to 15 rad/s - 215 rad/s, under the case of the effect of centrifugal force on nonlinear vibrating behavior. It demonstrates that the centrifugal force can significantly promote the performance of nonlinear energy harvesters.

  16. Segmentation-free x-ray energy spectrum estimation for computed tomography

    NASA Astrophysics Data System (ADS)

    Zhao, Wei; Zhang, Qiude; Niu, Tianye

    2016-03-01

    X-ray energy spectrum plays an essential role in imaging and related tasks. Due to the high photon flux of clinical CT scanners, most of the spectrum estimation methods are indirect and are usually suffered from various limitations. The recently proposed indirect transmission measurement-based method requires at least the segmentation of one material, which is insufficient for CT images of highly noisy and with artifacts. To combat for the bottleneck of spectrum estimation using segmented CT images, in this study, we develop a segmentation-free indirect transmission measurement based energy spectrum estimation method using dual-energy material decomposition. The general principle of the method is to compare polychromatic forward projection with raw projection to calibrate a set of unknown weights which are used to express the unknown spectrum together with a set of model spectra. After applying dual-energy material decomposition using high-and low-energy raw projection data, polychromatic forward projection is conducted on material-specific images. The unknown weights are then iteratively updated to minimize the difference between the raw projection and estimated projection. Both numerical simulations and experimental head phantom are used to evaluate the proposed method. The results indicate that the method provides accurate estimate of the spectrum and it may be attractive for dose calculations, artifacts correction and other clinical applications.

  17. Excitation energy dependent Raman spectrum of MoSe2

    PubMed Central

    Nam, Dahyun; Lee, Jae-Ung; Cheong, Hyeonsik

    2015-01-01

    Raman investigation of MoSe2 was carried out with eight different excitation energies. Seven peaks, including E1g, A1g, E2g1, and A2u2 peaks are observed in the range of 100–400 cm−1. The phonon modes are assigned by comparing the peak positions with theoretical calculations. The intensities of the peaks are enhanced at different excitation energies through resonance with different optical transitions. The A1g mode is enhanced at 1.58 and 3.82 eV, which are near the A exciton energy and the band-to-band transition between higher energy bands, respectively. The E2g1 mode is strongly enhanced with respect to the A1g mode for the 2.71- and 2.81-eV excitations, which are close to the C exciton energy. The different enhancements of the A1g and E2g1 modes are explained in terms of the symmetries of the exciton states and the exciton-phonon coupling. Other smaller peaks including E1g and A2u2 are forbidden but appear due to the resonance effect near optical transition energies. PMID:26601614

  18. Evolving Concepts on Adjusting Human Resting Energy Expenditure Measurements for Body Size

    PubMed Central

    Heymsfield, Steven B.; Thomas, Diana; Bosy-Westphal, Anja; Shen, Wei; Peterson, Courtney M.; Müller, Manfred J.

    2012-01-01

    Establishing if an adult’s resting energy expenditure (REE) is high or low for their body size is a pervasive question in nutrition research. Early workers applied body mass and height as size measures and formulated the Surface Law and Kleiber’s Law, although each has limitations when adjusting REE. Body composition methods introduced during the mid-twentieth century provided a new opportunity to identify metabolically homogeneous “active” compartments. These compartments all show improved correlations with REE estimates over body mass-height approaches, but collectively share a common limitation: REE-body composition ratios are not “constant” but vary across men and women and with race, age, and body size. The now-accepted alternative to ratio-based norms is to adjust for predictors by applying regression models to calculate “residuals” that establish if a REE is relatively high or low. The distinguishing feature of statistical REE-body composition models is a “non-zero” intercept of unknown origin. The recent introduction of imaging methods has allowed development of physiological tissue-organ based REE prediction models. Herein we apply these imaging methods to provide a mechanistic explanation, supported by experimental data, for the non-zero intercept phenomenon and in that context propose future research directions for establishing between subject differences in relative energy metabolism. PMID:22863371

  19. Evolving concepts on adjusting human resting energy expenditure measurements for body size.

    PubMed

    Heymsfield, S B; Thomas, D; Bosy-Westphal, A; Shen, W; Peterson, C M; Müller, M J

    2012-11-01

    Establishing if an adult's resting energy expenditure (REE) is high or low for their body size is a pervasive question in nutrition research. Early workers applied body mass and height as size measures and formulated the Surface Law and Kleiber's Law, although each has limitations when adjusting REE. Body composition methods introduced during the mid-20th century provided a new opportunity to identify metabolically homogeneous 'active' compartments. These compartments all show improved correlations with REE estimates over body mass-height approaches, but collectively share a common limitation: REE-body composition ratios are not 'constant' but vary across men and women and with race, age and body size. The now-accepted alternative to ratio-based norms is to adjust for predictors by applying regression models to calculate 'residuals' that establish if an REE is relatively high or low. The distinguishing feature of statistical REE-body composition models is a 'non-zero' intercept of unknown origin. The recent introduction of imaging methods has allowed development of physiological tissue-organ-based REE prediction models. Herein, we apply these imaging methods to provide a mechanistic explanation, supported by experimental data, for the non-zero intercept phenomenon and, in that context, propose future research directions for establishing between-subject differences in relative energy metabolism.

  20. An elliptically-polarizing undulator with phase adjustable energy and polarization

    NASA Astrophysics Data System (ADS)

    Lidia, Steve; Carr, Roger

    1994-08-01

    We present a planar helical undulator designed to produce elliptically-polarized light. Helical magnetic fields may be produced by a variety of undulators with four parallel cassettes of magnets. In our design, all cassettes are mounted in two planes on slides so that they may be moved parallel to the electron beam. This allows us to produce X-rays of left- or right-handed elliptical or circular polarization as well as horizontal or vertical linear polarization. In model calculations, we have found that by sliding the top pair of rows with respect to the bottom pair, or the left pair with respect to the right pair, we retain the polarization setting but change the magnetic field strength, and hence the X-ray energy. This allows us to select both energy and polarization by independent phase adjustments alone, without changing the gap between the rows. Such a design may be simpler to construct than an adjustable-gap machine. We present calculations that model its operation and its effects on an electron beam.

  1. Molecular frame Auger electron energy spectrum from N2

    NASA Astrophysics Data System (ADS)

    Cryan, J. P.; Glownia, J. M.; Andreasson, J.; Belkacem, A.; Berrah, N.; Blaga, C. I.; Bostedt, C.; Bozek, J.; Cherepkov, N. A.; DiMauro, L. F.; Fang, L.; Gessner, O.; Gühr, M.; Hajdu, J.; Hertlein, M. P.; Hoener, M.; Kornilov, O.; Marangos, J. P.; March, A. M.; McFarland, B. K.; Merdji, H.; Messerschmidt, M.; Petrović, V. S.; Raman, C.; Ray, D.; Reis, D. A.; Semenov, S. K.; Trigo, M.; White, J. L.; White, W.; Young, L.; Bucksbaum, P. H.; Coffee, R. N.

    2012-03-01

    Here we present the first angle-resolved, non-resonant (normal) Auger spectra for impulsively aligned nitrogen molecules. We have measured the angular pattern of Auger electron emission following K-shell photoionization by 1.1 keV photons from the Linac Coherent Light Source (LCLS). Using strong-field-induced molecular alignment to make molecular frame measurements is equally effective for both repulsive and quasi-bound final states. The capability to resolve Auger emission angular distributions in the molecular frame of reference provides a new tool for spectral assignments in congested Auger electron spectra that takes advantage of the symmetries of the final diction states. Based on our experimental results and theoretical predictions, we propose the assignment of the spectral features in the Auger electron spectrum.

  2. Band reject filtration of the excitation spectrum at energy dispersive X-ray spectroscopy of weak signals

    NASA Astrophysics Data System (ADS)

    Tur'yanskii, A. G.; Gizha, S. S.; Senkov, V. M.; Pirshin, I. V.; Stanishevskii, Ya. M.

    2016-09-01

    The possibility of the efficient band reject filtration of the continuous X-ray excitation spectrum in the energy range E ≥ 8 keV is demonstrated. This makes it possible to strongly increase the sensitivity of energy dispersive X-ray spectroscopy at detecting of weak fluorescence lines. Spectral rejection is implemented by transmitting a primary beam through highly oriented pyrolytic graphite with given structural parameters. Diffraction extinction in pyrolytic graphite ensures the possibility of reducing the intensity by more than 20 dB and rejecting the spectral band with a width of 1 keV. The reduction of statistical fluctuations of the background of elastically scattered radiation is achieved when the bottom of the formed spectral valley is adjusted to the analyzed fluorescence line. The proposed scheme of band reject filtration also allows the suppression of intense characteristic lines in the primary and scattered radiation spectra.

  3. Effect of directional distribution on non-linear energy transfer in wind wave spectrum

    NASA Astrophysics Data System (ADS)

    Lavrenov, I.; Krogstad, H.

    2003-04-01

    Different directional distribution is investigated from the point of view a non-linear energy transfer in wind wave spectrum. In order to produce a numerical simulation of the non-linear interaction in wind wave spectrum a method of numerical integration of the highest accuracy is used. It is shown that the value of non-linear energy transfer is very sensitive to details of frequency-angular approximation of wave spectrum. The non-linear energy transfer is non-zero in wide frequency - angular range, depending on spectrum angular distribution. The calculation results reveal the presence of non-linear energy transfer to spectral components, which propagation is opposite to wind direction for a wide spectrum angular distribution. It should be noted that neither the discrete interaction approximation (DIA) used in the WAM model (Komen et al., 1994), no diffusive approximation of the non-linear transfer (Pushkarev and Zakharov, 1999) are able not to produce this effect. Numerical results show that the bi-model angular distribution, obtained by Hwang et al. (2000) in field experiments, can be generated by the non-linear energy transfer, sending energy in side direction. Present study has been supported by the INTAS-99-666, INTAS-01-25, INTAS-01-234, INTAS-01-2156, RFBR- 01- 05-64846 Grants.

  4. [Application of the racial algorithm in energy dispersive X-ray fluorescence overlapped spectrum analysis].

    PubMed

    Zeng, Guo-Qiang; Luo, Yao-Yao; Ge, Liang-Quan; Zhang, Qing-Xian; Gu, Yi; Cheng, Feng

    2014-02-01

    In the energy dispersive X-ray fluorescence spectrum analysis, scintillation detector such as NaI (Tl) detector usually has a low energy resolution at around 8%. The low energy resolution causes problems in spectral data analysis especially in the high background and low counts condition, it is very limited to strip the overlapped spectrum, and the more overlapping the peaks are, the more difficult to peel the peaks, and the qualitative and quantitative analysis can't be carried out because we can't recognize the peak address and peak area. Based on genetic algorithm and immune algorithm, we build a new racial algorithm which uses the Euclidean distance as the judgment of evolution, the maximum relative error as the iterative criterion to be put into overlapped spectrum analysis, then we use the Gaussian function to simulate different overlapping degrees of the spectrum, and the racial algorithm is used in overlapped peak separation and full spectrum simulation, the peak address deviation is in +/- 3 channels, the peak area deviation is no more than 5%, and it is proven that this method has a good effect in energy dispersive X-ray fluorescence overlapped spectrum analysis.

  5. Observation of energy spectrum of electron albedo in low latitude region at Hyderabad, India

    NASA Technical Reports Server (NTRS)

    Verma, S. D.; Bhatnagar, S. P.

    1985-01-01

    The preliminary results are presented of the measurement of the energy spectrum of low energy (5-24 MeV) albedo electrons, moving upward as well as downwards, at about 37 km (-4 mb) altitude, over Hyderabad, India, in low latitude region. The flux and energy spectrum was observed by a bi-directional, multidetector charged particle telescope which was flown in a high altitude balloon on 8th December 1984. Results based on a quick look data acquisition and analysis system are presented here.

  6. Primary electron spectrometer, 18:63 UE: Electrostatic analyzer description and energy spectrum determination

    NASA Technical Reports Server (NTRS)

    Pongratz, M. B.

    1973-01-01

    The primary electron spectrometer used to detect auroral electrons on sounding rocket 18:63 UE is described. The spectrometer used exponentially decaying positive and negative voltages applied to spherical deflection plates for energy analysis. A method for determining the analyzer response which does not require the assumptions that the ratio of plate separation to mean radius, the entrance or the exit apertures are small is described. By comparison with experiment it is shown that the effect of neither entrance nor exit collimation can be ignored. The experimental and calculated values of the limiting orbits agree well. A non-iterative technique of unfolding the electron differential energy spectrum is described. This method does not require the usual assumption of a flat or histogram-type energy spectrum. The unfolded spectra using both this technique and one which assumes a flat spectrum are compared to actual input spectra. This technique is especially useful in analyzing peaked auroral electron energy spectra.

  7. Impact of energy density on liking for sweet beverages and caloric-adjustment conditioning in children.

    PubMed

    Remy, Eloïse; Divert, Camille; Rousselot, Juliette; Brondel, Laurent; Issanchou, Sylvie; Nicklaus, Sophie

    2014-10-01

    The contribution of sweet beverages to weight gain in children is controversial; the impact of these beverages on caloric adjustment needs clarification. We studied the influence of energy-density (ED) conditioning on the liking for sweet beverages and caloric adjustment after their consumption in children. We used a within-subject design. Forty-four 8-11-y-old children were exposed to the following 2 distinctly flavored, sweetened beverages: a high-energy (HE) version (150 kcal) and a no-energy (NE) version (0 kcal). During a 4-wk initial conditioning period, children were exposed either 2 or 7 times to each beverage. After a 3-wk stability period (without exposure), children were exposed 3 times to both beverages with a reversed association between the ED and flavor (4-wk reversed-conditioning period). Flavor liking and food intake during meals after the consumption of each beverage were assessed before and after each period. After the initial conditioning, the liking for both beverages increased (P < 0.001). After the stability period, the liking for the HE flavor was higher than for the NE flavor (P = 0.024). After the reversed conditioning, the liking for the flavor initially paired with the HE beverage tended to remain higher than for the NE flavor (P = 0.089). Initially, energy intakes during the meal did not differ after the consumption of NE or HE beverages. After the initial conditioning and up until the end of the reversed conditioning, energy intakes were lower after the HE beverage than after the NE beverage regardless of the beverage flavor (eg, after reversal; caloric compensation score: 29%). The number of exposures did not influence liking or energy intake. After the association between a flavor and ED and reversal of this association, liking may be first guided by ED and then the flavor firstly associated with ED, whereas the partial caloric compensation may consistently be guided by ED. This trial was registered at clinicaltrials.gov as NCT

  8. Electron energy spectrum in circularly polarized laser irradiated overdense plasma

    SciTech Connect

    Liu, C. S.; Tripathi, V. K.; Shao, Xi; Kumar, Pawan

    2014-10-15

    A circularly polarized laser normally impinged on an overdense plasma thin foil target is shown to accelerate the electrons in the skin layer towards the rear, converting the quiver energy into streaming energy exactly if one ignores the space charge field. The energy distribution of electrons is close to Maxwellian with an upper cutoff ε{sub max}=mc{sup 2}[(1+a{sub 0}{sup 2}){sup 1/2}−1], where a{sub 0}{sup 2}=(1+(2ω{sup 2}/ω{sub p}{sup 2})|a{sub in}|{sup 2}){sup 2}−1, |a{sub in}| is the normalized amplitude of the incident laser of frequency ω, and ω{sub p} is the plasma frequency. The energetic electrons create an electrostatic sheath at the rear and cause target normal sheath acceleration of protons. The energy gain by the accelerated ions is of the order of ε{sub max}.

  9. Energy spectrum transfer equations of solar wind turbulence

    SciTech Connect

    Tu, C.-Y.; Marsch, E.

    1996-07-20

    Recent studies of transfer equations for solar wind MHD turbulence are reviewed. Emphasis is placed on the comparison of theoretical with observational results. The Helios, Voyager and Ulysses missions provide opportunities to study the radial evolution of the power spectra, cross-helicity, Alfven ratio and minimum variance direction. Spectrum tranfer equations are a tool to explore theoretically the radial evolution of the fluctuations. The transfer equations are derived from the incompressible MHD equations. Generally, one needs to make assumptions about the nature of the fluctuations and their turbulent interactions, in order to derive models from which numerical results that can be compared with the observations are obtained. Results for special simple models, which involve only structures and assume strong mixing, or consider Alfven waves with weak turbulent interactions, or a superposition of outward Alfven waves with convected structures, are briefly discussed. The differences between various approaches for deriving and approximating the general transfer equations are elucidated. The references in this short review are not complete. An exhaustive list of papers can be found in the recent review of Tu and Marsch [1995a]. A related discussion may be also found in a detailed review by Goldstein et al. [1995a].

  10. All-particle cosmic ray energy spectrum measured with 26 IceTop stations

    NASA Astrophysics Data System (ADS)

    Abbasi, R.; Abdou, Y.; Abu-Zayyad, T.; Ackermann, M.; Adams, J.; Aguilar, J. A.; Ahlers, M.; Altmann, D.; Andeen, K.; Auffenberg, J.; Bai, X.; Baker, M.; Barwick, S. W.; Baum, V.; Bay, R.; Bazo Alba, J. L.; Beattie, K.; Beatty, J. J.; Bechet, S.; Becker, J. K.; Becker, K.-H.; Bell, M.; Benabderrahmane, M. L.; BenZvi, S.; Berdermann, J.; Berghaus, P.; Berley, D.; Bernardini, E.; Bertrand, D.; Besson, D. Z.; Bindig, D.; Bissok, M.; Blaufuss, E.; Blumenthal, J.; Boersma, D. J.; Bohm, C.; Bose, D.; Böser, S.; Botner, O.; Brayeur, L.; Brown, A. M.; Buitink, S.; Caballero-Mora, K. S.; Carson, M.; Casier, M.; Chirkin, D.; Christy, B.; Clevermann, F.; Cohen, S.; Cowen, D. F.; Cruz Silva, A. H.; D'Agostino, M. V.; Danninger, M.; Daughhetee, J.; Davis, J. C.; De Clercq, C.; Degner, T.; Descamps, F.; Desiati, P.; de Vries-Uiterweerd, G.; DeYoung, T.; Díaz-Vélez, J. C.; Dreyer, J.; Dumm, J. P.; Dunkman, M.; Eisch, J.; Ellsworth, R. W.; Engdegård, O.; Euler, S.; Evenson, P. A.; Fadiran, O.; Fazely, A. R.; Fedynitch, A.; Feintzeig, J.; Feusels, T.; Filimonov, K.; Finley, C.; Fischer-Wasels, T.; Flis, S.; Franckowiak, A.; Franke, R.; Gaisser, T. K.; Gallagher, J.; Gerhardt, L.; Gladstone, L.; Glüsenkamp, T.; Goldschmidt, A.; Goodman, J. A.; Góra, D.; Grant, D.; Groß, A.; Grullon, S.; Gurtner, M.; Ha, C.; Haj Ismail, A.; Hallgren, A.; Halzen, F.; Han, K.; Hanson, K.; Heereman, D.; Heimann, P.; Heinen, D.; Helbing, K.; Hellauer, R.; Hickford, S.; Hill, G. C.; Hoffman, K. D.; Hoffmann, B.; Homeier, A.; Hoshina, K.; Huelsnitz, W.; Hulth, P. O.; Hultqvist, K.; Hussain, S.; Ishihara, A.; Jacobi, E.; Jacobsen, J.; Japaridze, G. S.; Johansson, H.; Kappes, A.; Karg, T.; Karle, A.; Kiryluk, J.; Kislat, F.; Klein, S. R.; Klepser, S.; Köhne, J.-H.; Kohnen, G.; Kolanoski, H.; Köpke, L.; Kopper, S.; Koskinen, D. J.; Kowalski, M.; Krasberg, M.; Kroll, G.; Kunnen, J.; Kurahashi, N.; Kuwabara, T.; Labare, M.; Laihem, K.; Landsman, H.; Larson, M. J.; Lauer, R.; Lünemann, J.; Madsen, J.; Maruyama, R.; Mase, K.; Matis, H. S.; Meagher, K.; Merck, M.; Mészáros, P.; Meures, T.; Miarecki, S.; Middell, E.; Milke, N.; Miller, J.; Montaruli, T.; Morse, R.; Movit, S. M.; Nahnhauer, R.; Nam, J. W.; Naumann, U.; Nowicki, S. C.; Nygren, D. R.; Odrowski, S.; Olivas, A.; Olivo, M.; O'Murchadha, A.; Panknin, S.; Paul, L.; Pérez de los Heros, C.; Pieloth, D.; Posselt, J.; Price, P. B.; Przybylski, G. T.; Rawlins, K.; Redl, P.; Resconi, E.; Rhode, W.; Ribordy, M.; Richman, M.; Riedel, B.; Rodrigues, J. P.; Rothmaier, F.; Rott, C.; Ruhe, T.; Rutledge, D.; Ruzybayev, B.; Ryckbosch, D.; Sander, H.-G.; Santander, M.; Sarkar, S.; Schatto, K.; Scheel, M.; Schmidt, T.; Schöneberg, S.; Schönwald, A.; Schukraft, A.; Schulte, L.; Schultes, A.; Schulz, O.; Schunck, M.; Seckel, D.; Semburg, B.; Seo, S. H.; Sestayo, Y.; Seunarine, S.; Silvestri, A.; Smith, M. W. E.; Spiczak, G. M.; Spiering, C.; Stamatikos, M.; Stanev, T.; Stezelberger, T.; Stokstad, R. G.; Stößl, A.; Strahler, E. A.; Ström, R.; Stüer, M.; Sullivan, G. W.; Taavola, H.; Taboada, I.; Tamburro, A.; Ter-Antonyan, S.; Tilav, S.; Toale, P. A.; Toscano, S.; Tosi, D.; van Eijndhoven, N.; Van Overloop, A.; van Santen, J.; Vehring, M.; Voge, M.; Walck, C.; Waldenmaier, T.; Wallraff, M.; Walter, M.; Wasserman, R.; Weaver, Ch.; Wendt, C.; Westerhoff, S.; Whitehorn, N.; Wiebe, K.; Wiebusch, C. H.; Williams, D. R.; Wischnewski, R.; Wissing, H.; Wolf, M.; Wood, T. R.; Woschnagg, K.; Xu, C.; Xu, D. L.; Xu, X. W.; Yanez, J. P.; Yodh, G.; Yoshida, S.; Zarzhitsky, P.; Zoll, M.

    2013-04-01

    We report on a measurement of the cosmic ray energy spectrum with the IceTop air shower array, the surface component of the IceCube Neutrino Observatory at the South Pole. The data used in this analysis were taken between June and October, 2007, with 26 surface stations operational at that time, corresponding to about one third of the final array. The fiducial area used in this analysis was 0.122 km2. The analysis investigated the energy spectrum from 1 to 100 PeV measured for three different zenith angle ranges between 0° and 46°. Because of the isotropy of cosmic rays in this energy range the spectra from all zenith angle intervals have to agree. The cosmic-ray energy spectrum was determined under different assumptions on the primary mass composition. Good agreement of spectra in the three zenith angle ranges was found for the assumption of pure proton and a simple two-component model. For zenith angles θ < 30°, where the mass dependence is smallest, the knee in the cosmic ray energy spectrum was observed at about 4 PeV, with a spectral index above the knee of about -3.1. Moreover, an indication of a flattening of the spectrum above 22 PeV was observed.

  11. A New Method of Prompt Fission Neutron Energy Spectrum Unfolding

    SciTech Connect

    Zeynalova, O. V.; Zeynalov, Sh.; Hambsch, F.-J.; Oberstedt, S.

    2010-11-25

    The prompt neutron emission in spontaneous fission of {sup 252}Cf has been investigated applying digital signal electronics along with associated digital signal processing algorithms. The goal was to find out the reasons of a long time existing discrepancy between theoretical calculations and the measurements of prompt fission neutron (PFN) emission dependence on the total kinetic energy (TKE) of fission fragments (FF). On the one hand the {sup 252}Cf(sf) reaction is one of the main references for nuclear data, on the other hand the understanding of PFN emission mechanism is very important for nuclear fission theory. Using a twin Frisch-grid ionization chamber for fission fragment (FF) detection and a NE213-equivalent neutron detector in total about 10{sup 7} fission fragment-neutron coincidences have been registered. Fission fragment kinetic energy, mass and angular distribution, neutron time-of-flight and pulse shape have been investigated using a 12 bit waveform digitizer. The signal waveforms have been analyzed using digital signal processing algorithms. For the first time the dependence of the number of emitted neutrons as a function of total kinetic energy (TKE) of the fragments is in very good agreement with theoretical calculations in the range of TKE from 140-220 MeV.

  12. A New Method of Prompt Fission Neutron Energy Spectrum Unfolding

    NASA Astrophysics Data System (ADS)

    Zeynalova, O. V.; Zeynalov, Sh.; Hambsch, F.-J.; Oberstedt, S.

    2010-11-01

    The prompt neutron emission in spontaneous fission of 252Cf has been investigated applying digital signal electronics along with associated digital signal processing algorithms. The goal was to find out the reasons of a long time existing discrepancy between theoretical calculations and the measurements of prompt fission neutron (PFN) emission dependence on the total kinetic energy (TKE) of fission fragments (FF). On the one hand the 252Cf (sf) reaction is one of the main references for nuclear data, on the other hand the understanding of PFN emission mechanism is very important for nuclear fission theory. Using a twin Frisch-grid ionization chamber for fission fragment (FF) detection and a NE213-equivalent neutron detector in total about 107 fission fragment-neutron coincidences have been registered. Fission fragment kinetic energy, mass and angular distribution, neutron time-of-flight and pulse shape have been investigated using a 12 bit waveform digitizer. The signal waveforms have been analyzed using digital signal processing algorithms. For the first time the dependence of the number of emitted neutrons as a function of total kinetic energy (TKE) of the fragments is in very good agreement with theoretical calculations in the range of TKE from 140-220 MeV.

  13. Ultra high energy cosmic ray energy spectrum and composition using hybrid analysis with telescope array

    NASA Astrophysics Data System (ADS)

    Allen, Monica Gene

    Cosmic radiation was discovered in 1912. This year, the 100 th anniversary of the discovery, marks not only the major progress that has been made in understanding these particles, but also the remaining questions about them. Questions about their sources, acceleration mechanisms, propagation and composition are still unanswered. There are only two experiments currently running that have the ability to study cosmic rays in the Ultra High Energy (E > 1018.0 eV) regime. The Telescope Array studies Ultra High Energy Cosmic Rays (UHECRs) using a hybrid detector. Fluorescence telescopes measure the longitudinal development of the extensive air shower generated by a primary cosmic ray particle, while scintillator detectors measure the lateral distribution of secondary particles that hit the ground. The Middle Drum (MD) fluorescence telescope consists of 14 refurbished telescopes from the High Resolution Fly's Eye (HiRes) experiment, providing a direct link back to the HiRes experiment and data. The surface array is comprised of 507 Scintillator Detectors (SD) of a similar design as was used by the Akeno Giant Air Shower Array (AGASA), providing a link to that experiment as well. Studying TA hybrid events (events observed by both the FD and SD), makes the analysis presented in this work the lynchpin that connects the HiRes experiment to the AGASA experiment. This uniquely allows for a direct comparison between the two detection types and allows us to answer questions about the differences in the energy spectrum measurements shown by the two previous experiments. Furthermore, the hybrid analysis improves the geometrical reconstruction of the showers significantly. This provides a more accurate measurement of the energy of the primary particle and makes it possible to make an accurate prediction regarding the chemical composition of the cosmic ray particle. Historically, only the HiRes experiment and the Pierre Auger Observatory (PAO) have made significant composition

  14. Anisotropic decay of the energy spectrum in two-dimensional dense granular flows

    NASA Astrophysics Data System (ADS)

    Saitoh, Kuniyasu; Mizuno, Hideyuki

    2017-07-01

    We study anisotropic collective motions of two-dimensional granular particles under simple shear deformations. Employing molecular-dynamics simulations of large system sizes, we find that anisotropic fluidized bands develop in the system yielding under quasistatic deformations, where the spectrum of nonaffine velocities, which is associated with the energy spectrum for turbulent flows, exhibits a quadrupole structure. To explain theoretically the anisotropic spectrum, we derive hydrodynamic modes from a continuum model of dense granular materials, where we find that fluidized bands are caused by long-lived hydrodynamic fluctuations characterized by compressibility.

  15. PROBING THE INFLATON: SMALL-SCALE POWER SPECTRUM CONSTRAINTS FROM MEASUREMENTS OF THE COSMIC MICROWAVE BACKGROUND ENERGY SPECTRUM

    SciTech Connect

    Chluba, Jens; Erickcek, Adrienne L.; Ben-Dayan, Ido

    2012-10-20

    In the early universe, energy stored in small-scale density perturbations is quickly dissipated by Silk damping, a process that inevitably generates {mu}- and y-type spectral distortions of the cosmic microwave background (CMB). These spectral distortions depend on the shape and amplitude of the primordial power spectrum at wavenumbers k {approx}< 10{sup 4} Mpc{sup -1}. Here, we study constraints on the primordial power spectrum derived from COBE/FIRAS and forecasted for PIXIE. We show that measurements of {mu} and y impose strong bounds on the integrated small-scale power, and we demonstrate how to compute these constraints using k-space window functions that account for the effects of thermalization and dissipation physics. We show that COBE/FIRAS places a robust upper limit on the amplitude of the small-scale power spectrum. This limit is about three orders of magnitude stronger than the one derived from primordial black holes in the same scale range. Furthermore, this limit could be improved by another three orders of magnitude with PIXIE, potentially opening up a new window to early universe physics. To illustrate the power of these constraints, we consider several generic models for the small-scale power spectrum predicted by different inflation scenarios, including running-mass inflation models and inflation scenarios with episodes of particle production. PIXIE could place very tight constraints on these scenarios, potentially even ruling out running-mass inflation models if no distortion is detected. We also show that inflation models with sub-Planckian field excursion that generate detectable tensor perturbations should simultaneously produce a large CMB spectral distortion, a link that could potentially be established with PIXIE.

  16. Energy spectrum of argon ions emitted from Filippov type Sahand plasma focus

    NASA Astrophysics Data System (ADS)

    Mohammadnejad, M.; Pestehe, S. J.; Mohammadi, M. A.

    2013-07-01

    The energy and flux of the argon ions produced in Sahand plasma focus have been measured by employing a well-designed Faraday cup. The secondary electron emission effects on the ion signals are simulated and the dimensions of Faraday cup are optimized to minimize these effects. The measured ion energy spectrum is corrected for the ion energy loss and charge exchange in the background gas. The effects of the capacitor bank voltage and working gas pressure on the ion energy spectrum are also investigated. It has been shown that the emitted ion number per energy increases as the capacitor bank voltage increases. Decreasing the working gas pressure leads to the increase in the number of emitted ion per energy.

  17. Energy spectrum of argon ions emitted from Filippov type Sahand plasma focus.

    PubMed

    Mohammadnejad, M; Pestehe, S J; Mohammadi, M A

    2013-07-01

    The energy and flux of the argon ions produced in Sahand plasma focus have been measured by employing a well-designed Faraday cup. The secondary electron emission effects on the ion signals are simulated and the dimensions of Faraday cup are optimized to minimize these effects. The measured ion energy spectrum is corrected for the ion energy loss and charge exchange in the background gas. The effects of the capacitor bank voltage and working gas pressure on the ion energy spectrum are also investigated. It has been shown that the emitted ion number per energy increases as the capacitor bank voltage increases. Decreasing the working gas pressure leads to the increase in the number of emitted ion per energy.

  18. Energy spectrum of argon ions emitted from Filippov type Sahand plasma focus

    SciTech Connect

    Mohammadnejad, M.; Pestehe, S. J.; Mohammadi, M. A.

    2013-07-15

    The energy and flux of the argon ions produced in Sahand plasma focus have been measured by employing a well-designed Faraday cup. The secondary electron emission effects on the ion signals are simulated and the dimensions of Faraday cup are optimized to minimize these effects. The measured ion energy spectrum is corrected for the ion energy loss and charge exchange in the background gas. The effects of the capacitor bank voltage and working gas pressure on the ion energy spectrum are also investigated. It has been shown that the emitted ion number per energy increases as the capacitor bank voltage increases. Decreasing the working gas pressure leads to the increase in the number of emitted ion per energy.

  19. Adjusted and unadjusted energy usage rates both determine body fat and plasma leptin in male Fischer 344 rats.

    PubMed

    Greenberg, J A; Rahman, S; Saint-Preux, S; Owen, D R; Boozer, C N

    1999-10-01

    Previous studies of the relationship between plasma leptin and energy usage have yielded contradictory findings. The present study was therefore conducted to clearly distinguish and measure the energy usage rate and the energy usage rate adjusted for a surrogate of metabolically active tissue mass. We investigated the simultaneous relationships between these two measures of energy usage, leptin, and body fat in 21-month-old adult male Fischer 344 rats on three different long-term dietary regimens: (1) continuous ad libitum feeding (Ad-lib); (2) ad libitum feeding until early adulthood, and then continuous 60% caloric restriction (CR); and (3) ad libitum feeding until early adulthood, then 60% caloric restriction until 16 months, and then ad libitum feeding for 5 months (CR/Ad-lib). Two versions of the daily usage rate were measured: daily dietary caloric intake (DCI), and daily energy expenditure (EE) based on indirect calorimetry. Two versions of the metabolically active tissue mass were also measured: fat-free mass (FFM), and the sum of the weight of the heart, brain, liver, and kidneys. Energy usage rates were adjusted for these measures of metabolically active tissue mass to yield measures of the energy metabolic rate. Correlation, regression, and path analyses showed that both the energy usage rate and adjusted energy usage rate played important independent roles in determining body fat and plasma leptin, but only after multivariate techniques were used to account for the simultaneous interactions between variables. Increases in the energy usage rate were associated with increases in body fat and the adjusted energy usage rate. Increases in the adjusted energy usage rate were associated with decreases in body fat and plasma leptin. These findings suggest that differences in subjects adjusted energy usage rate could explain some of the apparently contradictory findings concerning the relationship between energy usage and plasma leptin in previously published

  20. Quantum harmonic oscillator: an elementary derivation of the energy spectrum

    NASA Astrophysics Data System (ADS)

    Borghi, Riccardo

    2017-03-01

    An elementary treatment of the quantum harmonic oscillator is proposed. No previous knowledge of linear differential equation theory or Fourier analysis are required, but rather only a few basics of elementary calculus. The pivotal role in our analysis is played by the sole particle localization constraint, which implies square integrability of stationary-state wavefunctions. The oscillator ground-state characterization is then achieved in a way that could be grasped, in principle, even by first-year undergraduates. A very elementary approach to build up and to characterize all higher-level energy eigenstates completes our analysis.

  1. Energy spectrum and optical transitions in C80 fullerene isomers

    NASA Astrophysics Data System (ADS)

    Lobanov, B. V.; Murzashev, A. I.

    2013-04-01

    The energy spectra of all isomers of the C80 fullerene have been calculated in terms of the Schubin-Wonsowskii-Hubbard model. On this basis, their optical absorption spectra have also been calculated. The optical absorption spectra calculated for the endohedral Ca@C80, Ba@C80, and Sr@C80 fullerenes with the I h symmetry agree well with the experimental data. This circumstance allows us to conclude that the optical absorption spectra of other isomers (for which experimental data are unavailable) obtained in this work can be used for their identification.

  2. Psychological Adjustment and Sibling Relationships in Siblings of Children with Autism Spectrum Disorders: Environmental Stressors and the Broad Autism Phenotype

    ERIC Educational Resources Information Center

    Petalas, Michael A.; Hastings, Richard P.; Nash, Susie; Hall, Louise M.; Joannidi, Helen; Dowey, Alan

    2012-01-01

    Research with siblings of children with Autism Spectrum Disorders (ASD) suggests that they may be at increased risk for behavioural and emotional problems and relatively poor sibling relationships. This study investigated a diathesis-stress model, whereby the presence of Broad Autism Phenotype features in the typically developing siblings might…

  3. Psychological Adjustment and Sibling Relationships in Siblings of Children with Autism Spectrum Disorders: Environmental Stressors and the Broad Autism Phenotype

    ERIC Educational Resources Information Center

    Petalas, Michael A.; Hastings, Richard P.; Nash, Susie; Hall, Louise M.; Joannidi, Helen; Dowey, Alan

    2012-01-01

    Research with siblings of children with Autism Spectrum Disorders (ASD) suggests that they may be at increased risk for behavioural and emotional problems and relatively poor sibling relationships. This study investigated a diathesis-stress model, whereby the presence of Broad Autism Phenotype features in the typically developing siblings might…

  4. Less-energy-dense diets of low-income women in California are associated with higher energy-adjusted diet costs

    USDA-ARS?s Scientific Manuscript database

    Low-energy-density diets have been shown to be associated with higher diet quality and with better health outcomes. However, such diets have also been associated with higher diet costs. This study examined the impact of dietary energy density on energy-adjusted diet costs among a sample of low-incom...

  5. Joint Resource Allocation of Spectrum Sensing and Energy Harvesting in an Energy-Harvesting-Based Cognitive Sensor Network.

    PubMed

    Liu, Xin; Lu, Weidang; Ye, Liang; Li, Feng; Zou, Deyue

    2017-03-16

    The cognitive sensor (CS) can transmit data to the control center in the same spectrum that is licensed to the primary user (PU) when the absence of the PU is detected by spectrum sensing. However, the battery energy of the CS is limited due to its small size, deployment in atrocious environments and long-term working. In this paper, an energy-harvesting-based CS is described, which senses the PU together with collecting the radio frequency energy to supply data transmission. In order to improve the transmission performance of the CS, we have proposed the joint resource allocation of spectrum sensing and energy harvesting in the cases of a single energy-harvesting-based CS and an energy-harvesting-based cognitive sensor network (CSN), respectively. Based on the proposed frame structure, we have formulated the resource allocation as a class of joint optimization problems, which seek to maximize the transmission rate of the CS by jointly optimizing sensing time, harvesting time and the numbers of sensing nodes and harvesting nodes. Using the half searching method and the alternating direction optimization, we have achieved the sub-optimal solution by converting the joint optimization problem into several convex sub-optimization problems. The simulation results have indicated the predominance of the proposed energy-harvesting-based CS and CSN models.

  6. Joint Resource Allocation of Spectrum Sensing and Energy Harvesting in an Energy-Harvesting-Based Cognitive Sensor Network

    PubMed Central

    Liu, Xin; Lu, Weidang; Ye, Liang; Li, Feng; Zou, Deyue

    2017-01-01

    The cognitive sensor (CS) can transmit data to the control center in the same spectrum that is licensed to the primary user (PU) when the absence of the PU is detected by spectrum sensing. However, the battery energy of the CS is limited due to its small size, deployment in atrocious environments and long-term working. In this paper, an energy-harvesting-based CS is described, which senses the PU together with collecting the radio frequency energy to supply data transmission. In order to improve the transmission performance of the CS, we have proposed the joint resource allocation of spectrum sensing and energy harvesting in the cases of a single energy-harvesting-based CS and an energy-harvesting-based cognitive sensor network (CSN), respectively. Based on the proposed frame structure, we have formulated the resource allocation as a class of joint optimization problems, which seek to maximize the transmission rate of the CS by jointly optimizing sensing time, harvesting time and the numbers of sensing nodes and harvesting nodes. Using the half searching method and the alternating direction optimization, we have achieved the sub-optimal solution by converting the joint optimization problem into several convex sub-optimization problems. The simulation results have indicated the predominance of the proposed energy-harvesting-based CS and CSN models. PMID:28300763

  7. Measurement of electron-positron spectrum in high-energy cosmic rays in the PAMELA experiment

    NASA Astrophysics Data System (ADS)

    Karelin, A. V.; Adriani, O.; Barbarino, G. C.; Bazilevskaya, G. A.; Bellotti, R.; Boezio, M.; Bogomolov, E. A.; Bongi, M.; Bonvicini, V.; Bottai, S.; Bruno, A.; Cafagna, F.; Campana, D.; Carbone, R.; Carlson, P.; Casolino, M.; Castellini, G.; De Donato, C.; De Santis, C.; De Simone, N.; Di Felice, V.; Formato, V.; Galper, A. M.; Koldashov, S. V.; Koldobskiy, S. A.; Krutkov, S. Y.; Kvashnin, A. N.; Leonov, A. A.; Mayorov, A. G.; Malakhov, V. V.; Marcelli, L.; Martucci, M.; Menn, W.; Merge, M.; Mikhailov, V. V.; Mocchiutti, E.; Monaco, A.; Mori, N.; Munini, R.; Osteria, G.; Palma, F.; Panico, B.; Papini, P.; Pearce, M.; Picozza, P.; Ricci, M.; Ricciarini, S. B.; Sarkar, R.; Scotti, V.; Rossetto, L.; Simon, M.; Sparvoli, R.; Spillantini, P.; Vacchi, A.; Vannuccini, E.; Vasilyev, G. I.; Voronov, S. A.; Yurkin, Y. T.; Zampa, G.; Zampa, N.

    2015-08-01

    At present the existing data on the cosmic ray electron energy spectra in the high energy range are fragmented, and the situation is exacerbated by their small number. In the satellite PAMELA experiment measurements at high energies are carried out by the calorimeter. The experimental data accumulated for more than 8 years of measurements, with the information of the calorimeter, the neutron detector and the scintillation counters made it possible to obtain the total spectrum of high-energy electrons and positrons in energy range 0.3-3 TeV.

  8. Buying less and wasting less food. Changes in household food energy purchases, energy intakes and energy density between 2007 and 2012 with and without adjustment for food waste.

    PubMed

    Whybrow, Stephen; Horgan, Graham W; Macdiarmid, Jennie I

    2017-05-01

    Consumers in the UK responded to the rapid increases in food prices between 2007 and 2009 partly by reducing the amount of food energy bought. Household food and drink waste has also decreased since 2007. The present study explored the combined effects of reductions in food purchases and waste on estimated food energy intakes and dietary energy density. The amount of food energy purchased per adult equivalent was calculated from Kantar Worldpanel household food and drink purchase data for 2007 and 2012. Food energy intakes were estimated by adjusting purchase data for food and drink waste, using waste factors specific to the two years and scaled for household size. Scotland. Households in Scotland (n 2657 in 2007; n 2841 in 2012). The amount of food energy purchased decreased between 2007 and 2012, from 8·6 to 8·2 MJ/adult equivalent per d (P<0·001). After accounting for the decrease in food waste, estimated food energy intake was not significantly different (7·3 and 7·2 MJ/adult equivalent per d for 2007 and 2012, respectively; P=0·186). Energy density of foods purchased increased slightly from 700 to 706 kJ/100 g (P=0·010). While consumers in Scotland reduced the amount of food energy that they purchased between 2007 and 2012, this was balanced by reductions in household food and drink waste over the same time, resulting in no significant change in net estimated energy intake of foods brought into the home.

  9. Energy spectrum of cosmic-ray iron nucleus observed with emulsion chamber

    NASA Technical Reports Server (NTRS)

    Sato, Y.; Shimada, E.; Ohta, I.; Tasaka, S.; Tanaka, S.; Sugimoto, H.; Taira, K.; Tateyama, N.

    1985-01-01

    Energy spectrum of cosmic-ray Fe-nucleus has been measured from 4 GeV per nucleon to beyond 100 GeV per nucleon. The data were obtained using emulsion chambers on a balloon from Sanriku, Japan. The energies were estimated by the opening angle method after calibrated using 1.88 GeV per nucleon Fe collisions. The spectrum of Fe is approximately E-2.5 in the range from 10 to 200 GeV per nucleon. This result is in good agreement with those of other experiments.

  10. Determination of energy spectrum parameters for two-dimensional carriers from the quantum oscillation beating pattern

    NASA Astrophysics Data System (ADS)

    Dorozhkin, S. I.

    1990-02-01

    Recent experimental results of Das et al. and of Luo et al. on the Shubnikov-de Haas oscillation beatings in two-dimensional electron systems (2D ES) are quantitatively described in terms of a model based on the energy spectrum of a 2D ES with strong spin-orbit coupling. Values of the energy spectrum parameters, including the g factor, are obtained for two-dimensional electrons in InxGa1-xAs/In0.52Al0.48As (x~=0.6) heterostructures.

  11. Energy spectrum and critical exponents of the free parafermion Z N spin chain

    NASA Astrophysics Data System (ADS)

    Alcaraz, Francisco C.; Batchelor, Murray T.; Liu, Zi-Zhong

    2017-04-01

    Results are given for the ground state energy and excitation spectrum of a simple N-state Z N spin chain described by free parafermions. The model is non-Hermitian for N≥slant 3 with a real ground state energy and a complex excitation spectrum. Although having a simpler Hamiltonian than the superintegrable chiral Potts model, the model is seen to share some properties with it, e.g. the specific heat exponent α =1-2/N and the anisotropic correlation length exponents {ν\\parallel}=1 and {ν\\bot}=2/N .

  12. Energy spectrum of extragalactic gamma-ray sources

    NASA Technical Reports Server (NTRS)

    Protheroe, R. J.

    1985-01-01

    The result of Monte Carlo electron photon cascade calculations for propagation of gamma rays through regions of extragalactic space containing no magnetic field are given. These calculations then provide upper limits to the expected flux from extragalactic sources. Since gamma rays in the 10 to the 14th power eV to 10 to the 17th power eV energy range are of interest, interactions of electrons and photons with the 3 K microwave background radiation are considered. To obtain an upper limit to the expected gamma ray flux from sources, the intergalactic field is assumed to be so low that it can be ignored. Interactions with photons of the near-infrared background radiation are not considered here although these will have important implications for gamma rays below 10 to the 14th power eV if the near infrared background radiation is universal. Interaction lengths of electrons and photons in the microwave background radiation at a temperature of 2.96 K were calculated and are given.

  13. All-Particle Cosmic Ray Energy Spectrum Measured with 26 Icetop Stations

    NASA Technical Reports Server (NTRS)

    Abbasi, R.; Abdou, Y.; Abu-Zayyad, T.; Ackermann, M.; Adams, J.; Aguilar, J. A.; Ahlers, M.; Altmann, D.; Andeen, K.; Auffenberg, J.; Bai, X.; Baker, M.; Barwick, S. W.; Baum, V.; Bay, R.; Bazo Alba, J. L.; Beattie, K.; Beatty, J. J.; Bechet, S.; Becker, J. K.; Becker, K.-H; Bell, M.; Benabderrahmane, M. L.; BenZvi, S.; Stamatikos, M.

    2013-01-01

    We report on a measurement of the cosmic ray energy spectrum with the IceTop air shower array, thesurface component of the IceCube Neutrino Observatory at the South Pole. The data used in this analysiswere taken between June and October, 2007, with 26 surface stations operational at that time, corresponding to about one third of the final array. The fiducial area used in this analysis was 0.122 square kilometers.The analysis investigated the energy spectrum from 1 to 100 PeV measured for three different zenithangle ranges between 0 and 46. Because of the isotropy of cosmic rays in this energy range the spectrafrom all zenith angle intervals have to agree. The cosmic-ray energy spectrum was determined under differentassumptions on the primary mass composition. Good agreement of spectra in the three zenithangle ranges was found for the assumption of pure proton and a simple two-component model. Forzenith angles theta less than 30 deg., where the mass dependence is smallest, the knee in the cosmic ray energy spectrumwas observed at about 4 PeV, with a spectral index above the knee of about -3.1. Moreover, an indicationof a flattening of the spectrum above 22 PeV was observed.

  14. Scaling-law for the energy dependence of anatomic power spectrum in dedicated breast CT

    SciTech Connect

    Vedantham, Srinivasan; Shi, Linxi; Glick, Stephen J.; Karellas, Andrew

    2013-01-15

    Purpose: To determine the x-ray photon energy dependence of the anatomic power spectrum of the breast when imaged with dedicated breast computed tomography (CT). Methods: A theoretical framework for scaling the empirically determined anatomic power spectrum at one x-ray photon energy to that at any given x-ray photon energy when imaged with dedicated breast CT was developed. Theory predicted that when the anatomic power spectrum is fitted with a power curve of the form k f{sup -{beta}}, where k and {beta} are fit coefficients and f is spatial frequency, the exponent {beta} would be independent of x-ray photon energy (E), and the amplitude k scales with the square of the difference in energy-dependent linear attenuation coefficients of fibroglandular and adipose tissues. Twenty mastectomy specimens based numerical phantoms that were previously imaged with a benchtop flat-panel cone-beam CT system were converted to 3D distribution of glandular weight fraction (f{sub g}) and were used to verify the theoretical findings. The 3D power spectrum was computed in terms of f{sub g} and after converting to linear attenuation coefficients at monoenergetic x-ray photon energies of 20-80 keV in 5 keV intervals. The 1D power spectra along the axes were extracted and fitted with a power curve of the form k f{sup -{beta}}. The energy dependence of k and {beta} were analyzed. Results: For the 20 mastectomy specimen based numerical phantoms used in the study, the exponent {beta} was found to be in the range of 2.34-2.42, depending on the axis of measurement. Numerical simulations agreed with the theoretical predictions that for a power-law anatomic spectrum of the form k f{sup -{beta}}, {beta} was independent of E and k(E) =k{sub 1}[{mu}{sub g}(E) -{mu}{sub a}(E)]{sup 2}, where k{sub 1} is a constant, and {mu}{sub g}(E) and {mu}{sub a}(E) represent the energy-dependent linear attenuation coefficients of fibroglandular and adipose tissues, respectively. Conclusions: Numerical

  15. Holographic lens spectrum splitting photovoltaic system for increased diffuse collection and annual energy yield

    NASA Astrophysics Data System (ADS)

    Vorndran, Shelby D.; Wu, Yuechen; Ayala, Silvana; Kostuk, Raymond K.

    2015-09-01

    Concentrating and spectrum splitting photovoltaic (PV) modules have a limited acceptance angle and thus suffer from optical loss under off-axis illumination. This loss manifests itself as a substantial reduction in energy yield in locations where a significant portion of insulation is diffuse. In this work, a spectrum splitting PV system is designed to efficiently collect and convert light in a range of illumination conditions. The system uses a holographic lens to concentrate shortwavelength light onto a smaller, more expensive indium gallium phosphide (InGaP) PV cell. The high efficiency PV cell near the axis is surrounded with silicon (Si), a less expensive material that collects a broader portion of the solar spectrum. Under direct illumination, the device achieves increased conversion efficiency from spectrum splitting. Under diffuse illumination, the device collects light with efficiency comparable to a flat-panel Si module. Design of the holographic lens is discussed. Optical efficiency and power output of the module under a range of illumination conditions from direct to diffuse are simulated with non-sequential raytracing software. Using direct and diffuse Typical Metrological Year (TMY3) irradiance measurements, annual energy yield of the module is calculated for several installation sites. Energy yield of the spectrum splitting module is compared to that of a full flat-panel Si reference module.

  16. Spectrum measurement with the Telescope Array Low Energy Extension (TALE) fluorescence detector

    NASA Astrophysics Data System (ADS)

    Zundel, Zachary James

    The Telescope Array (TA) experiment is the largest Ultra High Energy cosmic ray observatory in the northern hemisphere and is designed to be sensitive to cosmic ray air showers above 1018eV. Despite the substantial measurements made by TA and AUGER (the largest cosmic ray observatory in the southern hemisphere), there remains uncertainty about whether the highest energy cosmic rays are galactic or extragalactic in origin. Locating features in the cosmic ray energy spectrum below 1018eV that indicate a transition from galactic to extragalactic sources would clarify the interpretation of measurements made at the highest energies. The Telescope Array Low Energy Extension (TALE) is designed to extend the energy threshold of the TA observatory down to 1016.5eV in order to make such measurements. This dissertation details the construction, calibration, and operation of the TALE flu- orescence detector. A measurement of the flux of cosmic rays in the energy range of 1016.5 -- 1018.5eV is made using the monocular data set taken between September 2013 and January 2014. The TALE fluorescence detector observes evidence for a softening of the cosmic spectrum at 1017.25+/-0.5eV. The evidence of a change in the spectrum motivates continued study of 1016.5 -- 1018.5eV cosmic rays.

  17. Energy-efficient routing, modulation and spectrum allocation in elastic optical networks

    NASA Astrophysics Data System (ADS)

    Tan, Yanxia; Gu, Rentao; Ji, Yuefeng

    2017-07-01

    With tremendous growth in bandwidth demand, energy consumption problem in elastic optical networks (EONs) becomes a hot topic with wide concern. The sliceable bandwidth-variable transponder in EON, which can transmit/receive multiple optical flows, was recently proposed to improve a transponder's flexibility and save energy. In this paper, energy-efficient routing, modulation and spectrum allocation (EE-RMSA) in EONs with sliceable bandwidth-variable transponder is studied. To decrease the energy consumption, we develop a Mixed Integer Linear Programming (MILP) model with corresponding EE-RMSA algorithm for EONs. The MILP model jointly considers the modulation format and optical grooming in the process of routing and spectrum allocation with the objective of minimizing the energy consumption. With the help of genetic operators, the EE-RMSA algorithm iteratively optimizes the feasible routing path, modulation format and spectrum resources solutions by explore the whole search space. In order to save energy, the optical-layer grooming strategy is designed to transmit the lightpath requests. Finally, simulation results verify that the proposed scheme is able to reduce the energy consumption of the network while maintaining the blocking probability (BP) performance compare with the existing First-Fit-KSP algorithm, Iterative Flipping algorithm and EAMGSP algorithm especially in large network topology. Our results also demonstrate that the proposed EE-RMSA algorithm achieves almost the same performance as MILP on an 8-node network.

  18. Seasonal adjustment of energy budget in a large wild mammal, the Przewalski horse (Equus ferus przewalskii) II. Energy expenditure.

    PubMed

    Arnold, Walter; Ruf, Thomas; Kuntz, Regina

    2006-11-01

    Many large mammals show pronounced seasonal fluctuations of metabolic rate (MR). It has been argued, based on studies in ruminants, that this variation merely results from different levels of locomotor activity (LA), and heat increment of feeding (HI). However, a recent study in red deer (Cervus elaphus) identified a previously unknown mechanism in ungulates--nocturnal hypometabolism--that contributed significantly to reduced energy expenditure, mainly during late winter. The relative contribution of these different mechanisms to seasonal adjustments of MR is still unknown, however. Therefore, in the study presented here we quantified for the first time the independent contribution of thermoregulation, LA and HI to heart rate (f(H)) as a measure of MR in a free-roaming large ungulate, the Przewalski horse or Takhi (Equus ferus przewalskii Poljakow). f(H) varied periodically throughout the year with a twofold increase from a mean of 44 beats min(-1) during December and January to a spring peak of 89 beats min(-1) at the beginning of May. LA increased from 23% per day during December and January to a mean level of 53% per day during May, and declined again thereafter. Daily mean subcutaneous body temperature (T(s)) declined continuously during winter and reached a nadir at the beginning of April (annual range was 5.8 degrees C), well after the annual low of air temperature and LA. Lower T(s) during winter contributed considerably to the reduction in f(H). In addition to thermoregulation, f(H) was affected by reproduction, LA, HI and unexplained seasonal variation, presumably reflecting to some degree changes in organ mass. The observed phase relations of seasonal changes indicate that energy expenditure was not a consequence of energy uptake but is under endogenous control, preparing the organism well in advance of seasonal energetic demands.

  19. An Energy-Efficient Game-Theory-Based Spectrum Decision Scheme for Cognitive Radio Sensor Networks.

    PubMed

    Salim, Shelly; Moh, Sangman

    2016-06-30

    A cognitive radio sensor network (CRSN) is a wireless sensor network in which sensor nodes are equipped with cognitive radio. In this paper, we propose an energy-efficient game-theory-based spectrum decision (EGSD) scheme for CRSNs to prolong the network lifetime. Note that energy efficiency is the most important design consideration in CRSNs because it determines the network lifetime. The central part of the EGSD scheme consists of two spectrum selection algorithms: random selection and game-theory-based selection. The EGSD scheme also includes a clustering algorithm, spectrum characterization with a Markov chain, and cluster member coordination. Our performance study shows that EGSD outperforms the existing popular framework in terms of network lifetime and coordination overhead.

  20. An Energy-Efficient Game-Theory-Based Spectrum Decision Scheme for Cognitive Radio Sensor Networks

    PubMed Central

    Salim, Shelly; Moh, Sangman

    2016-01-01

    A cognitive radio sensor network (CRSN) is a wireless sensor network in which sensor nodes are equipped with cognitive radio. In this paper, we propose an energy-efficient game-theory-based spectrum decision (EGSD) scheme for CRSNs to prolong the network lifetime. Note that energy efficiency is the most important design consideration in CRSNs because it determines the network lifetime. The central part of the EGSD scheme consists of two spectrum selection algorithms: random selection and game-theory-based selection. The EGSD scheme also includes a clustering algorithm, spectrum characterization with a Markov chain, and cluster member coordination. Our performance study shows that EGSD outperforms the existing popular framework in terms of network lifetime and coordination overhead. PMID:27376290

  1. A new neutron energy spectrum unfolding code using a two steps genetic algorithm

    NASA Astrophysics Data System (ADS)

    Shahabinejad, H.; Hosseini, S. A.; Sohrabpour, M.

    2016-03-01

    A new neutron spectrum unfolding code TGASU (Two-steps Genetic Algorithm Spectrum Unfolding) has been developed to unfold the neutron spectrum from a pulse height distribution which was calculated using the MCNPX-ESUT computational Monte Carlo code. To perform the unfolding process, the response matrices were generated using the MCNPX-ESUT computational code. Both one step (common GA) and two steps GAs have been implemented to unfold the neutron spectra. According to the obtained results, the new two steps GA code results has shown closer match in all energy regions and particularly in the high energy regions. The results of the TGASU code have been compared with those of the standard spectra, LSQR method and GAMCD code. The results of the TGASU code have been demonstrated to be more accurate than that of the existing computational codes for both under-determined and over-determined problems.

  2. Spectrum sensing algorithm based on autocorrelation energy in cognitive radio networks

    NASA Astrophysics Data System (ADS)

    Ren, Shengwei; Zhang, Li; Zhang, Shibing

    2016-10-01

    Cognitive radio networks have wide applications in the smart home, personal communications and other wireless communication. Spectrum sensing is the main challenge in cognitive radios. This paper proposes a new spectrum sensing algorithm which is based on the autocorrelation energy of signal received. By taking the autocorrelation energy of the received signal as the statistics of spectrum sensing, the effect of the channel noise on the detection performance is reduced. Simulation results show that the algorithm is effective and performs well in low signal-to-noise ratio. Compared with the maximum generalized eigenvalue detection (MGED) algorithm, function of covariance matrix based detection (FMD) algorithm and autocorrelation-based detection (AD) algorithm, the proposed algorithm has 2 11 dB advantage.

  3. Balloon measurements of the energy spectrum of cosmic electrons between 1 and 25 GeV.

    NASA Technical Reports Server (NTRS)

    Earl, J. A.; Neely, D. E.; Rygg, T. A.

    1972-01-01

    During three balloon flights made in 1966 and 1967, cosmic electrons were investigated with the aid of a hodoscope detector that provided extensive and detailed information on each cosmic-ray event triggering the apparatus. Similar information obtained during calibration exposures to protons and pions as well as to electrons was used to provide identification of cosmic electrons and to determine their energies. Differential primary electron intensities measured in the range from 1 to 25 GeV were substantially larger than some earlier measurements. In conjunction with existing measurements at energies above 100 GeV, this finding indicates that the energy spectrum of cosmic electrons is steeper than that of cosmic-ray nuclei and consequently suggests that Compton/synchrotron energy loss plays a significant role in shaping the electron spectrum.

  4. Prompt neutron fission spectrum mean energies for the fissile nuclides and /sup 252/Cf

    SciTech Connect

    Holden, N.E.

    1985-01-01

    The international standard for a neutron spectrum is that produced from the spontaneous fission of /sup 252/Cf, while the thermal neutron induced fission neutron spectra for the four fissile nuclides, /sup 233/U, /sup 235/U, /sup 239/Pu, and /sup 241/Pu are of interest from the standpoint of nuclear reactors. The average neutron energies of these spectra are tabulated. The individual measurements are recorded with the neutron energy range measured, the method of detection as well as the average neutron energy for each author. Also tabulated are the measurements of the ratio of mean energies for pairs of fission neutron spectra. 75 refs., 9 tabs. (LEW)

  5. Energy Spectrum and Composition of Ultra High Energy Cosmic Ray Showers Using Hybrid Analysis from Telescope Array

    NASA Astrophysics Data System (ADS)

    Jui, Charles; Allen, Monica; Abu-Zayyad, Tareq; Stokes, Benjamin; Ivanov, Dmitri

    2013-04-01

    The Telescope Array (TA) consists of 38 fluorescence telescopes spread over three detector sites. The three sites at located the periphery of a surface array of 507 scintillation counters, covering 700 square km, with a spacing of 1.2 km. TA is designed to study the energy spectrum, composition, and arrival direction anisotropy of ultrahigh energy cosmic rays (UHECR). A unique feature of TA is that one of three fluorescence detector (FD) sites, Middle Drum (MD), is instrumented with 14 refurbished telescopes from the High Resolution Fly's Eye (HiRes) experiment. This commonality provides TA with a direct link back to the HiRes experiment and data. Using the scintillator detector data in conjunction with the MD data improves the geometrical reconstruction and hence provides a more accurate reconstruction of the energy of the primary particle and shower profile. The Middle Drum hybrid spectrum composition results will be presented.

  6. Anisotropy and nonuniversality in scaling laws of the large-scale energy spectrum in rotating turbulence.

    PubMed

    Sen, Amrik; Mininni, Pablo D; Rosenberg, Duane; Pouquet, Annick

    2012-09-01

    Rapidly rotating turbulent flow is characterized by the emergence of columnar structures that are representative of quasi-two-dimensional behavior of the flow. It is known that when energy is injected into the fluid at an intermediate scale Lf, it cascades towards smaller as well as larger scales. In this paper we analyze the flow in the inverse cascade range at a small but fixed Rossby number, Rof≈0.05. Several numerical simulations with helical and nonhelical forcing functions are considered in periodic boxes with unit aspect ratio. In order to resolve the inverse cascade range with reasonably large Reynolds number, the analysis is based on large eddy simulations which include the effect of helicity on eddy viscosity and eddy noise. Thus, we model the small scales and resolve explicitly the large scales. We show that the large-scale energy spectrum has at least two solutions: one that is consistent with Kolmogorov-Kraichnan-Batchelor-Leith phenomenology for the inverse cascade of energy in two-dimensional (2D) turbulence with a ∼k⊥-5/3 scaling, and the other that corresponds to a steeper ∼k⊥-3 spectrum in which the three-dimensional (3D) modes release a substantial fraction of their energy per unit time to the 2D modes. The spectrum that emerges depends on the anisotropy of the forcing function, the former solution prevailing for forcings in which more energy is injected into the 2D modes while the latter prevails for isotropic forcing. In the case of anisotropic forcing, whence the energy goes from the 2D to the 3D modes at low wave numbers, large-scale shear is created, resulting in a time scale τsh, associated with shear, thereby producing a ∼k-1 spectrum for the total energy with the horizontal energy of the 2D modes still following a ∼k⊥-5/3 scaling.

  7. Size distribution and energy spectrum in the mixed state induced by Rayleigh-Taylor instability.

    PubMed

    Hazak, G; Elbaz, Y; Gardner, J H; Velikovich, A L; Schmitt, A J; Zalesak, S T

    2006-04-01

    A study--based on simulations and experiments as well as analytical derivations--of the internal structure of the fragmented ("mixed") state induced by the Rayleigh-Taylor instability at the interface between two fluids is presented. The distribution of sizes and the energy spectrum in the fragmented state are derived from the symmetries exhibited by the data and by dimensional analysis.

  8. Contribution of tilt boundaries to the total energy spectrum of grain boundaries in polycrystals

    NASA Astrophysics Data System (ADS)

    Straumal, B. B.; Protsenko, P. V.; Straumal, A. B.; Rodin, A. O.; Kucheev, Yu. O.; Gusak, A. M.; Murashov, V. A.

    2013-01-01

    By measuring temperatures T w for the transition from the incomplete to complete wetting of grain boundaries in poly- and bicrystals, the width of the spectrum of tilt grain boundaries and their contribution to the total energy spectrum of grain boundaries in polycrystals have been experimentally estimated. It has been shown that the tilt grain boundaries correspond to a rather narrow (only 5-10%) portion in the total energy spectrum of grain boundaries in polycrystals. In metals with a low stacking fault energy (copper, tin, zinc), the tilt grain boundaries belong to 10-20% of the grain boundaries with the highest transition temperatures T w (hence, with low energies). In a metal with a high stacking fault energy (aluminum), the values of T w for the tilt grain boundaries lie nearly in the middle between the minimum ( T w,min) and maximum ( T w,max) transition temperatures from the incomplete to complete wetting of grain boundaries. This means that grain boundaries with the structure corresponding to a lower energy than that of the symmetric twin boundaries (or stacking faults) can exist in aluminum.

  9. The effect of stochastic re-acceleration on the energy spectrum of shock-accelerated protons

    SciTech Connect

    Afanasiev, Alexandr; Vainio, Rami; Kocharov, Leon

    2014-07-20

    The energy spectra of particles in gradual solar energetic particle (SEP) events do not always have a power-law form attributed to the diffusive shock acceleration mechanism. In particular, the observed spectra in major SEP events can take the form of a broken (double) power law. In this paper, we study the effect of a process that can modify the power-law spectral form produced by the diffusive shock acceleration: the stochastic re-acceleration of energetic protons by enhanced Alfvénic turbulence in the downstream region of a shock wave. There are arguments suggesting that this process can be important when the shock propagates in the corona. We consider a coronal magnetic loop traversed by a shock and perform Monte Carlo simulations of interactions of shock-accelerated protons with Alfvén waves in the loop. The wave-particle interactions are treated self-consistently, so the finiteness of the available turbulent energy is taken into account. The initial energy spectrum of particles is taken to be a power law. The simulations reveal that the stochastic re-acceleration leads either to the formation of a spectrum that is described in a wide energy range by a power law (although the resulting power-law index is different from the initial one) or to a broken power-law spectrum. The resulting spectral form is determined by the ratio of the energy density of shock-accelerated protons to the wave energy density in the shock's downstream region.

  10. Determination of the Spectral Index in the Fission Spectrum Energy Regime

    SciTech Connect

    Lee, Amy Sarah

    2016-05-16

    Neutron reaction cross sections play a vital role in tracking the production and destruction of isotopes exposed to neutron fluence. They are central to the process of reconciling the initial and final atom inventories. Measurements of irradiated samples by radiochemical methods in tangent with an algorithm are used to evaluate the fluence a sample is exposed to over the course of the irradiation. This algorithm is the Isotope Production Code (IPC) created and used by the radiochemistry data assessment team at Los Alamos National Laboratory (LANL). An integral result is calculated by varying the total neutron fluence seen by a sample. A sample, irradiated in a critical assembly, will be exposed to a unique neutron flux defined by the neutron source and distance of the sample from the source. Neutron cross sections utilized are a function of the hardness of the neutron spectrum at the location of irradiation. A spectral index is used an indicator of the hardness of the neutron spectrum. Cross sections fit forms applied in IPC are collapsed from a LANL 30-group energy structure. Several decades of research and development have been performed to formalize the current IPC cross section library. Basis of the current fission spectrum neutron reaction cross section library is rooted in critical assembly experiments performed from the 1950’s through the early 1970’s at LANL. The focus of this report is development of the spectral index used an indicator of the hardness of the neutron spectrum in the fission spectrum energy regime.

  11. A two-stage spectrum sensing scheme based on energy detection and a novel multitaper method

    NASA Astrophysics Data System (ADS)

    Qi, Pei-Han; Li, Zan; Si, Jiang-Bo; Xiong, Tian-Yi

    2015-04-01

    Wideband spectrum sensing has drawn much attention in recent years since it provides more opportunities to the secondary users. However, wideband spectrum sensing requires a long time and a complex mechanism at the sensing terminal. A two-stage wideband spectrum sensing scheme is considered to proceed spectrum sensing with low time consumption and high performance to tackle this predicament. In this scheme, a novel multitaper spectrum sensing (MSS) method is proposed to mitigate the poor performance of energy detection (ED) in the low signal-to-noise ratio (SNR) region. The closed-form expression of the decision threshold is derived based on the Neyman-Pearson criterion and the probability of detection in the Rayleigh fading channel is analyzed. An optimization problem is formulated to maximize the probability of detection of the proposed two-stage scheme and the average sensing time of the two-stage scheme is analyzed. Numerical results validate the efficiency of MSS and show that the two-stage spectrum sensing scheme enjoys higher performance in the low SNR region and lower time cost in the high SNR region than the single-stage scheme. Project supported by the National Natural Science Foundation of China (Grant No. 61301179), the China Postdoctoral Science Foundation (Grant No. 2014M550479), and the Doctorial Programs Foundation of the Ministry of Education, China (Grant No. 20110203110011).

  12. Study of the energy spectrum of primary cosmic rays: EAS size fluctuations at a fixed primary energy

    NASA Technical Reports Server (NTRS)

    Allev, N.; Alimov, T.; Kakhharov, N.; Khakimov, K.; Rakhimova, N.; Tashpulatov, R.; Khristiansen, G. B.

    1985-01-01

    During the initial period of the Samarkand EAS array operations the showers were selected on the basis of charged-particle flux density, and during the subsequent periods the showers were selected on the basis of Cerenkov light flux density. This procedure made it possible to measure the shower energy, to estimate the EAS size fluctuations at a fixed primary energy, and to experimentally obtain the scaling factor K(Ne, Eo) from the EAS size spectrum to the primary energy spectrum. Six scintillators of area S = 2 sq m each were added to the array. The fluctuations of EAS sizes in the showers of fixed primary energies and the scaling factors K(Ne, Eo) were inferred from the data obtained. The showers with zenith angles 30 deg were selected. The EAS axis positions were inferred from the amplitude data of the scintillators. The primary energy Eo was determined by the method of least squares for the known EAS axis position using the data of the Cerenkov detector located at 80 to 150 m EAS axis. It is shown that the Cerenkov light flux fluctuations at 100 m from EAS axis, q sub 100, do not exceed 10% at a fixed EAS energy, so the parameter q sub 100 may be used to estimate the EAS-generating primary particle-energy.

  13. Broadband source spectrum, seismic energy, and stress drop of the 1989 Macquarie Ridge earthquake

    SciTech Connect

    Houston, H. )

    1990-06-01

    The author computes the broadband source spectrum at periods from 1 to 50 seconds using teleseismic P body waves of the May 23, 1989 Macquarie Ridge earthquake (M{sub W} = 8.1) recorded by the GDSN, GEOSCOPE, and IDA networks. The average source spectrum is obtained by windowing, tapering, and Fourier-transforming P waves, removing from the spectra the effects of attenuation, geometrical spreading, and radiation pattern, and averaging logarithmically over the stations. The source spectrum for the strike-slip Macquarie Ridge earthquake is higher than an average source spectrum of seven recent large earthquakes (scaled to be comparable to a M{sub W} = 8.1 earthquake) by a factor of 2 to 3 at periods of 1 to 20 seconds. These other earthquakes were underthrusting events in subduction zones. Using Haskell's formulation assuming a point source with no directivity, she estimates the seismically radiated energy from the source spectrum by integrating the square of the source spectrum in velocity and scaling the result. The seismic energy thus estimated for the Macquarie Ridge earthquake is 3 to 8 {times} 10{sup 23} ergs. An Orowan stress drop can be obtained from the seismic energy and moment. The Orowan stress drop for the Macquarie Ridge earthquake is about 20 to 50 bars, much higher than similarly determined stress drops of other recent large earthquakes. There is a correlation between the Orowan stress drops and time since the last earthquake of comparable or larger magnitude for seven recent large earthquakes. This correlation suggests that a healing process operates that may control the mechanical strength of the fault and is important on time scales of tens to hundreds of years.

  14. The research of hyperspectral image EBCOT lossless compression coding technology based on inter-spectrum adjustable parameter matrix reversible transform and intra-frame IDWT

    NASA Astrophysics Data System (ADS)

    Xie, Cheng-jun; Wei, Ying; Bi, Xin-wen; Li, Hui-zhu

    2009-10-01

    This paper presents a new reversible transform of inter-spectrum adjustable parameter matrix, which has better redundancy elimination effect by adjusting magnitude parameter λ and shift parameter δ to adjust transform matrix. Intraframe redundancy is eliminated by integer discrete wavelet transform (IDWT).These two kinds of transforms are all completed entirely by addition and shift, whose fast operation speed makes hardware implementation easier. After interspectrum and intra-frame transform, the hyper-spectral image is coded by improved EBCOT algorithm. Using hyper-spectral images Canal shot by AVIRIS of American JPL laboratory as test images, the experimental results show that in lossless image compression applications the method proposed in this paper is much better than the research results of MST, NIMST, a research team of Chinese Academy of Sciences, DPCMARJ, WinZip and JPEG-LS. The condition in which λ=7 and δ=3 in this paper, on the average the compression ratio using this algorithm increases by 11%, 15%, 18%, 31%, 36%, 38% and 43% respectively compared to the above algorithms. From the foregoing it follows that the algorithm presented in this paper is a very good hyper-spectral image lossless compression coding algorithm.

  15. Mars Energy Spectrum studies from Assimilated MCS data using the UK MGCM

    NASA Astrophysics Data System (ADS)

    Valeanu, Alexandru; Read, Peter; Wang, Yixiong; Lewis, Stephen; Montabone, Luca; Tabataba-Vakili, Fachreddin

    2015-04-01

    Introduction The energy spectrum (ES) analysis is a renowned tool for understanding the driving mechanisms behind atmospheric turbulence (Lindborg, 1998). We aim to investigate whether energy and enstrophy inertial ranges exist in the kinetic energy spectrum (KES), and to quantify the corresponding cascades (with their ranges), and relationship with the atmospheric forcing and energy dissipation scales. The calculation of the ES from observational data is known to be highly non-trivial due to the lack of global coverage in space and time. Gage and Nastrom (1984) were the first to overcome this problem for Earth but this has not so far been attempted for Mars. Our approach is to take the sparse observational data and assimilate it using a global numerical model. We present preliminary results using the Mars Climate Sounder (MCS) retrievals and the LMD-UK Mars GCM (MGCM). This was pioneered by Lewis and Read (1999). Methodology The equations we used to calculate the Eddy and Zonal Mean kinetic energies are derived from total KES formula presented in Lindborg and Augier (2013). Hence, adding the two spectra together, we obtain the full KES spectrum as presented in their paper. For the Available Potential Energy Spectrum (APES), we have used a preliminary simplified version of the approach presented in Lindborg and Augier (2013). The Energy Spectra To date we have assimilated the MCS data at the resolution of T31 (triangular truncation), hence the ES only spans up to total wavenumber 31. This encompasses a portion of the energy inertial range, which might be expected to manifest the -3 exponential law by analogy with the Earth (Gage & Nastrom, 1984). Features: - velocities and corresponding KEs are higher with increasing height compared to Earth, - "-3" slope is restricted to ~30 km altitude, suggesting an early departure from the enstrophy inertial range, - boundary layer velocities are similar to Earth References 1. Gage and Nastrom, A Climatology of Atmospheric

  16. Lorentz Invariance Violation and the Observed Spectrum of Ultrahigh Energy Cosmic Rays

    NASA Technical Reports Server (NTRS)

    Scully, S. T.; Stecker, F. W.

    2009-01-01

    There has been much interest in possible violations of Lorentz invariance, particularly motivated by quantum gravity theories. It has been suggested that a small amount of Lorentz invariance violation (LIV) could turn of photomeson interactions of ultrahigh energy cosmic rays (UHECRs) with photons of the cosmic background radiation and thereby eliminate the resulting sharp steepening in the spectrum of the highest energy CRs predicted by Greisen Zatsepin and Kuzmin (GZK). Recent measurements of the UHECR spectrum reported by the HiRes and Auger collaborations, however, indicate the presence of the GZK effect. We present the results of a detailed calculation of the modification of the UHECR spectrum caused by LIV using the formalism of Coleman and Glashow. We then compare these results with the experimental UHECR data from Auger and HiRes. Based on these data, we find a best fit amount of LIV of 4.5+1:5 ..4:5 x 10(exp -23),consistent with an upper limit of 6 x 10(exp -23). This possible amount of LIV can lead to a recovery of the cosmic ray spectrum at higher energies than presently observed. Such an LIV recovery effect can be tested observationally using future detectors.

  17. Using the energy spectrum measured by DAMA/LIBRA to probe light dark matter

    SciTech Connect

    Chang, Spencer; Weiner, Neal; Pierce, Aaron

    2009-06-01

    A weakly interacting massive particle (WIMP) weighing only a few GeV has been invoked as an explanation for the signal from the DAMA/LIBRA experiment. We show that the data from DAMA/LIBRA are now powerful enough to strongly constrain the properties of any putative WIMP. Accounting for the detailed recoil spectrum, a light WIMP with a Maxwellian velocity distribution and a spin-independent interaction cannot account for the data. Even neglecting the spectrum, significant parameter space is excluded by a limit that can be derived from the DAMA unmodulated signal at low energies. Appreciable modification to the astrophysics or particle physics can open light mass windows.

  18. Spectrum and energy levels of five-times ionized zirconium (Zr VI)

    NASA Astrophysics Data System (ADS)

    Reader, Joseph; Lindsay, Mark D.

    2016-02-01

    We carried out a new analysis of the spectrum of five-times-ionized zirconium Zr VI. For this we used sliding-spark discharges together with normal- and grazing-incidence spectrographs to observe the spectrum from 160 to 2000 Å. These observations showed that the analysis of this spectrum by Khan et al (1985 Phys. Scr. 31 837) contained a significant number of incorrect energy levels. We have now classified ˜420 lines as transitions between 23 even-parity levels 73 odd-parity levels. The 4s24p5, 4s4p6, 4s24p44d, 5s, 5d, 6s configurations are now complete, although a few levels of 4s24p45d are tentative. We determined Ritz-type wavelengths for ˜135 lines from the optimized energy levels. The uncertainties range from 0.0003 to 0.0020 Å. Hartree-Fock calculations and least-squares fits of the energy parameters to the observed levels were used to interpret the observed configurations. Oscillator strengths for all classified lines were calculated with the fitted parameters. The results are compared with values for the level energies, percentage compositions, and transition probabilities from recent ab initio theoretical calculations. The ionization energy was revised to 777 380 ± 300 cm-1 (96.38 ± 0.04 eV).

  19. Measurements of the spectrum and energy dependence of X-ray transition radiation

    NASA Technical Reports Server (NTRS)

    Cherry, M. L.

    1978-01-01

    The results of experiments designed to test the theory of X-ray transition radiation and to verify the predicted dependence of the characteristic features of the radiation on the radiator dimensions are presented. The X-ray frequency spectrum produced by 5- to 9-GeV electrons over the range 4 to 30 keV was measured with a calibrated single-crystal Bragg spectrometer, and at frequencies up to 100 keV with an NaI scintillator. The interference pattern in the spectrum and the hardening of the radiation with increasing foil thickness are clearly observed. The energy dependence of the total transition-radiation intensity was studied using a radiator with large dimensions designed to yield energy-dependent signals at very high particle energies, up to E/mc-squared approximately equal to 100,000. The results are in good agreement with the theoretical predictions.

  20. Integration of Semiconducting Sulfides for Full-Spectrum Solar Energy Absorption and Efficient Charge Separation.

    PubMed

    Zhuang, Tao-Tao; Liu, Yan; Li, Yi; Zhao, Yuan; Wu, Liang; Jiang, Jun; Yu, Shu-Hong

    2016-05-23

    The full harvest of solar energy by semiconductors requires a material that simultaneously absorbs across the whole solar spectrum and collects photogenerated electrons and holes separately. The stepwise integration of three semiconducting sulfides, namely ZnS, CdS, and Cu2-x S, into a single nanocrystal, led to a unique ternary multi-node sheath ZnS-CdS-Cu2-x S heteronanorod for full-spectrum solar energy absorption. Localized surface plasmon resonance (LSPR) in the nonstoichiometric copper sulfide nanostructures enables effective NIR absorption. More significantly, the construction of pn heterojunctions between Cu2-x S and CdS leads to staggered gaps, as confirmed by first-principles simulations. This band alignment causes effective electron-hole separation in the ternary system and hence enables efficient solar energy conversion. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Material grain size characterization method based on energy attenuation coefficient spectrum and support vector regression.

    PubMed

    Li, Min; Zhou, Tong; Song, Yanan

    2016-07-01

    A grain size characterization method based on energy attenuation coefficient spectrum and support vector regression (SVR) is proposed. First, the spectra of the first and second back-wall echoes are cut into several frequency bands to calculate the energy attenuation coefficient spectrum. Second, the frequency band that is sensitive to grain size variation is determined. Finally, a statistical model between the energy attenuation coefficient in the sensitive frequency band and average grain size is established through SVR. Experimental verification is conducted on austenitic stainless steel. The average relative error of the predicted grain size is 5.65%, which is better than that of conventional methods. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. Energy spectrum of cosmic ray protons and helium nuclei measured by the ARGO-YBJ experiment

    NASA Astrophysics Data System (ADS)

    Mari, S. M.; Montini, P.

    2014-04-01

    The ARGO-YBJ experiment is a full-coverage air shower detector operating at the Yangbajing International Cosmic Ray Observatory (Tibet, PR China, 4300 m a.s.l.). The detector was in stable data taking in its full configuration from November 2007 to February 2013. More than 5 ×1011 events have been collected and reconstructed. Due to its characteristics (full-coverage, high segmentation, high altitude operation) the ARGO-YBJ experiment is able to investigate the cosmic ray energy spectrum in a wide energy range and offer the possibility of measuring the cosmic ray light component spectrum down to the TeV region, where direct balloon-borne measurements are available. In this work we present the measurement of the proton and helium spectra in the energy range 1-300 TeV by using a large data sample collected between January 2008 and December 2011.

  3. The energy spectrum of 662 keV photons in a water equivalent phantom

    NASA Astrophysics Data System (ADS)

    Akar Tarim, U.; Gurler, O.; Ozmutlu, E. N.; Yalcin, S.; Gundogdu, O.; Sharaf, J. M.; Bradley, D. A.

    2012-07-01

    Investigation is made on the energy spectrum of photons originating from interactions of 662 keV primary gamma-ray photons emitted by a point source positioned at the centre of a water equivalent solid phantom of dimensions 19 cm×19 cm×24 cm. Peaks resulting from total energy loss (photopeak) and multiple and back scattering have been observed using a 51 mm×51 mm NaI(Tl) detector; good agreement being found between the measured and simulated response functions. The energy spectrum of the gamma photons obtained through the Monte Carlo simulation reveals local maxima at about 100 keV and 210 keV, being also observed in the experimental response function. Such spectra can be used as a method of testing the water equivalence of solid phantom media before their use for dosimetry measurements.

  4. The Cosmic Ray Energy Spectrum and Related Measurements with the Pierre Auger Observatory

    SciTech Connect

    Abraham, : J.; Abreu, P.; Aglietta, M.; Aguirre, C.; Ahn, E.J.; Allard, D.; Allekotte, I.; Allen, J.; Alvarez-Muniz, J.; Ambrosio, M.; Anchordoqui, L.

    2009-06-01

    These are presentations to be presented at the 31st International Cosmic Ray Conference, in Lodz, Poland during July 2009. It consists of the following presentations: (1) Measurement of the cosmic ray energy spectrum above 10{sup 18} eV with the Pierre Auger Observatory; (2) The cosmic ray flux observed at zenith angles larger than 60 degrees with the Pierre Auger Observatory; (3) Energy calibration of data recorded with the surface detectors of the Pierre Auger Observatory; (4) Exposure of the Hybrid Detector of The Pierre Auger Observatory; and (5) Energy scale derived from Fluorescence Telescopes using Cherenkov Light and Shower Universality.

  5. Contribution from individual nearby sources to the spectrum of high-energy cosmic-ray electrons

    NASA Astrophysics Data System (ADS)

    Sedrati, R.; Attallah, R.

    2014-04-01

    In the last few years, very important data on high-energy cosmic-ray electrons and positrons from high-precision space-born and ground-based experiments have attracted a great deal of interest. These particles represent a unique probe for studying local comic-ray accelerators because they lose energy very rapidly. These energy losses reduce the lifetime so drastically that high-energy cosmic-ray electrons can attain the Earth only from rather local astrophysical sources. This work aims at calculating, by means of Monte Carlo simulation, the contribution from some known nearby astrophysical sources to the cosmic-ray electron/positron spectra at high energy (≥ 10 GeV). The background to the electron energy spectrum from distant sources is determined with the help of the GALPROP code. The obtained numerical results are compared with a set of experimental data.

  6. Characterizing a Neutron Energy Spectrum Using a "Forward Edge" Neutron Time-of-Flight Spectroscopy Technique

    DTIC Science & Technology

    2005-03-01

    energy spectrum of monoenergetic neutron source [9:562]..............................................27 16. Example data set...is valid only when the absorber is composed of one material and the incident neutrons are monoenergetic . In the case where the absorber consists of...source due to its creation from monoenergetic neutrons . Figure 15: Proton recoil energy spectrum of monoenergetic neutron source [9:562

  7. Numerical Experiments on the Detailed Energy Conversion and Spectrum Studies in a Corona Current Sheet

    NASA Astrophysics Data System (ADS)

    Ni, Lei; Lin, Jun; Mei, Zhixing; Li, Yan

    2015-10-01

    In this paper, we study the energy conversion and spectra in a corona current sheet (CS) by 2.5 dimensional MHD numerical simulations. Numerical results show that many Petschek-like fine structures with slow-mode shocks mediated by plasmoid instabilities develop during the magnetic reconnection process. The termination shocks can also be formed above the primary magnetic island and at the head of secondary islands. These shocks play important roles in generating thermal energy in a corona CS. For a numerical simulation with initial conditions close to the solar corona environment, the ratio of the generated thermal energy to the total dissipated magnetic energy is around 1/5 before secondary islands appear. After secondary islands appear, the generated thermal energy starts to increase sharply and this ratio can reach a value of about 3/5. In an environment with a relatively lower plasma density and plasma β, the plasma can be heated to a much higher temperature. After secondary islands appear, the one-dimensional energy spectra along the CS do not behave as a simple power law and the spectrum index increases with the wave number. The average spectrum index for the magnetic energy spectrum along the CS is about 1.8. The two-dimensional spectra intuitively show that part of the high energy is cascaded to large kx and ky space after secondary islands appear. The plasmoid distribution function calculated from numerical simulations behaves as a power law closer to f(\\psi )˜ {\\psi }-1 in the intermediate ψ regime. By using {η }{eff}={v}{inflow}\\cdot L, the effective magnetic diffusivity is estimated to be about 1011 ˜ 1012 m2 s-1.

  8. Dosimetric effects of energy spectrum uncertainties in radiation therapy with laser-driven particle beams.

    PubMed

    Schell, S; Wilkens, J J

    2012-03-07

    Laser-driven particle acceleration is a potentially cost-efficient and compact new technology that might replace synchrotrons or cyclotrons for future proton or heavy-ion radiation therapy. Since the energy spectrum of laser-accelerated particles is rather wide, compared to the monoenergetic beams of conventional machines, studies have proposed the usage of broader spectra for the treatment of at least certain parts of the target volume to make the process more efficient. The thereby introduced additional uncertainty in the applied energy spectrum is analysed in this note. It is shown that the uncertainty can be categorized into a change of the total number of particles, and a change in the energy distribution of the particles. The former one can be monitored by a simple fluence detector and cancels for a high number of statistically fluctuating shots. The latter one, the redistribution of a fixed number of particles to different energy bins in the window of transmitted energies of the energy selection system, only introduces smaller changes to the resulting depth dose curve. Therefore, it might not be necessary to monitor this uncertainty for all applied shots. These findings might enable an easier uncertainty management for particle therapy with broad energy spectra.

  9. Diffuse gamma radiation. [intensity, energy spectrum and spatial distribution from SAS 2 observations

    NASA Technical Reports Server (NTRS)

    Fichtel, C. E.; Simpson, G. A.; Thompson, D. J.

    1978-01-01

    Results are reported for an investigation of the intensity, energy spectrum, and spatial distribution of the diffuse gamma radiation detected by SAS 2 away from the galactic plane in the energy range above 35 MeV. The gamma-ray data are compared with relevant data obtained at other wavelengths, including 21-cm emission, radio continuum radiation, and the limited UV and radio information on local molecular hydrogen. It is found that there are two quite distinct components to the diffuse radiation, one of which shows a good correlation with the galactic matter distribution and continuum radiation, while the other has a much steeper energy spectrum and appears to be isotropic at least on a coarse scale. The galactic component is interpreted in terms of its implications for both local and more distant regions of the Galaxy. The apparently isotropic radiation is discussed partly with regard to the constraints placed on possible models by the steep energy spectrum, the observed intensity, and an upper limit on the anisotropy.

  10. Screening and comparison of polychromatic and monochromatic image reconstruction of abdominal arterial energy spectrum CT.

    PubMed

    Wang, X P; Wang, B; Hou, P; Li, R; Gao, J B

    2017-01-01

    We screened the suitable image reconstruction to observe the abdominal artery and compare the quality between the polychromatic and the monochromatic reconstruction images of the abdominal artery spectrum CT. Eighty patients underwent Gemstone CT energy spectrum imaging to obtain an abdominal artery polychromatic image (140 kVp) and a monochromatic image from 40 ~ 140 keV. The CT value of region of interest (ROI) was measured on the polychromatic image and the single energy image. The signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of the abdominal aorta and hepatic artery were determined. The images in each group underwent image quality subjective scoring by three experienced radiologists using a blinded method. Finally, comprehensive comparisons and image quality subjective scorings were performed on the CT, SNR, and CNR values of the abdominal aorta. The obtained data were statistically analyzed by SPSS 19.0 software. When the keV value was reduced, the CT value of the abdominal artery gradually increased, and the image noise also changed. The comprehensive comparisons and subjective scorings were finalized for each single energy image based on the abdominal artery image quality objective indicators (CT value, SNR, and CNR). Results revealed that the abdominal artery image quality in the 50 ~ 60 keV monochromatic group was better compared to the polychromatic group. Furthermore, onochromatic imaging had different impacts on the abdominal aorta and hepatic artery image qualities. In different types of abdominal arterial reconstruction images obtained using abdominal energy spectrum CT conventional enhanced scanning, the image quality of the 50 ~ 60keV monochromatic reconstruction was higher when compared with the polychromatic reconstruction. Thus, it is recommended to apply the conventional reconstruction for abdominal artery energy spectrum CT scanning.

  11. Evidence for Spatial Variation in the High-Energy Spectrum of the Galactic Center Excess

    NASA Astrophysics Data System (ADS)

    Kwa, Anna; Horiuchi, Shunsaku; Kaplinghat, Manoj

    2017-01-01

    Fermi Large Area Telescope observations towards the Milky Way center have revealed a spatially extended source of gamma rays in excess of the modeled astrophysical backgrounds. Possible explanations for this `galactic center excess' include weakly-interacting massive particle dark matter annihilations, unresolved milllisecond pulsars, and cosmic-ray outbursts from the galactic center. I will discuss an analysis comparing the spatial morphology and spectrum of the excess signal in the innermost few degrees of the galactic center versus the outlying sky regions. We find that the excess spectrum above 10 GeV is spatially varying: the spectrum extends above these energies outside of 5° in galactocentric radius, but cuts off sharply by 10 GeV in the innermost few degrees. If interpreted as a real feature of the excess, this radial variation in the spectrum has important implications for both astrophysical and dark matter interpretations of the galactic center excess. Single-component dark matter annihilation models face challenges in reproducing this variation; on the other hand, a population of unresolved millisecond pulsars contributing both prompt and secondary inverse Compton emission may be able to explain the spectrum as well as its spatial dependency. Supported by NSF GRFP Grant No. DGE-1321846.

  12. Neutron energy spectrum influence on irradiation hardening and microstructural development of tungsten

    DOE PAGES

    Fukuda, Makoto; Kiran Kumar, N. A. P.; Koyanagi, Takaaki; ...

    2016-07-02

    We performed a neutron irradiation to single crystal pure tungsten in the mixed spectrum High Flux Isotope Reactor (HFIR). In order to investigate the influences of neutron energy spectrum, the microstructure and irradiation hardening were compared with previous data obtained from the irradiation campaigns in the mixed spectrum Japan Material Testing Reactor (JMTR) and the sodium-cooled fast reactor Joyo. The irradiation temperatures were in the range of ~90–~800 °C and fast neutron fluences were 0.02–9.00 × 1025 n/m2 (E > 0.1 MeV). Post irradiation evaluation included Vickers hardness measurements and transmission electron microscopy. Moreover, the hardness and microstructure changes exhibitedmore » a clear dependence on the neutron energy spectrum. The hardness appeared to increase with increasing thermal neutron flux when fast fluence exceeds 1 × 1025 n/m2 (E > 0.1 MeV). Finally, irradiation induced precipitates considered to be χ- and σ-phases were observed in samples irradiated to >1 × 1025 n/m2 (E > 0.1 MeV), which were pronounced at high dose and due to the very high thermal neutron flux of HFIR. Although the irradiation hardening mainly caused by defects clusters in a low dose regime, the transmutation-induced precipitation appeared to impose additional significant hardening of the tungsten.« less

  13. Neutron energy spectrum influence on irradiation hardening and microstructural development of tungsten

    NASA Astrophysics Data System (ADS)

    Fukuda, Makoto; Kiran Kumar, N. A. P.; Koyanagi, Takaaki; Garrison, Lauren M.; Snead, Lance L.; Katoh, Yutai; Hasegawa, Akira

    2016-10-01

    Neutron irradiation to single crystal pure tungsten was performed in the mixed spectrum High Flux Isotope Reactor (HFIR). To investigate the influences of neutron energy spectrum, the microstructure and irradiation hardening were compared with previous data obtained from the irradiation campaigns in the mixed spectrum Japan Material Testing Reactor (JMTR) and the sodium-cooled fast reactor Joyo. The irradiation temperatures were in the range of ∼90-∼800 °C and fast neutron fluences were 0.02-9.00 × 1025 n/m2 (E > 0.1 MeV). Post irradiation evaluation included Vickers hardness measurements and transmission electron microscopy. The hardness and microstructure changes exhibited a clear dependence on the neutron energy spectrum. The hardness appeared to increase with increasing thermal neutron flux when fast fluence exceeds 1 × 1025 n/m2 (E > 0.1 MeV). Irradiation induced precipitates considered to be χ- and σ-phases were observed in samples irradiated to >1 × 1025 n/m2 (E > 0.1 MeV), which were pronounced at high dose and due to the very high thermal neutron flux of HFIR. Although the irradiation hardening mainly caused by defects clusters in a low dose regime, the transmutation-induced precipitation appeared to impose additional significant hardening of the tungsten.

  14. Neutron energy spectrum influence on irradiation hardening and microstructural development of tungsten

    SciTech Connect

    Fukuda, Makoto; Kiran Kumar, N. A. P.; Koyanagi, Takaaki; Garrison, Lauren M.; Snead, Lance L.; Katoh, Yutai; Hasegawa, Akira

    2016-07-02

    We performed a neutron irradiation to single crystal pure tungsten in the mixed spectrum High Flux Isotope Reactor (HFIR). In order to investigate the influences of neutron energy spectrum, the microstructure and irradiation hardening were compared with previous data obtained from the irradiation campaigns in the mixed spectrum Japan Material Testing Reactor (JMTR) and the sodium-cooled fast reactor Joyo. The irradiation temperatures were in the range of ~90–~800 °C and fast neutron fluences were 0.02–9.00 × 1025 n/m2 (E > 0.1 MeV). Post irradiation evaluation included Vickers hardness measurements and transmission electron microscopy. Moreover, the hardness and microstructure changes exhibited a clear dependence on the neutron energy spectrum. The hardness appeared to increase with increasing thermal neutron flux when fast fluence exceeds 1 × 1025 n/m2 (E > 0.1 MeV). Finally, irradiation induced precipitates considered to be χ- and σ-phases were observed in samples irradiated to >1 × 1025 n/m2 (E > 0.1 MeV), which were pronounced at high dose and due to the very high thermal neutron flux of HFIR. Although the irradiation hardening mainly caused by defects clusters in a low dose regime, the transmutation-induced precipitation appeared to impose additional significant hardening of the tungsten.

  15. Neutron energy spectrum influence on irradiation hardening and microstructural development of tungsten

    SciTech Connect

    Fukuda, Makoto; Kiran Kumar, N. A. P.; Koyanagi, Takaaki; Garrison, Lauren M.; Snead, Lance L.; Katoh, Yutai; Hasegawa, Akira

    2016-07-02

    We performed a neutron irradiation to single crystal pure tungsten in the mixed spectrum High Flux Isotope Reactor (HFIR). In order to investigate the influences of neutron energy spectrum, the microstructure and irradiation hardening were compared with previous data obtained from the irradiation campaigns in the mixed spectrum Japan Material Testing Reactor (JMTR) and the sodium-cooled fast reactor Joyo. The irradiation temperatures were in the range of ~90–~800 °C and fast neutron fluences were 0.02–9.00 × 1025 n/m2 (E > 0.1 MeV). Post irradiation evaluation included Vickers hardness measurements and transmission electron microscopy. Moreover, the hardness and microstructure changes exhibited a clear dependence on the neutron energy spectrum. The hardness appeared to increase with increasing thermal neutron flux when fast fluence exceeds 1 × 1025 n/m2 (E > 0.1 MeV). Finally, irradiation induced precipitates considered to be χ- and σ-phases were observed in samples irradiated to >1 × 1025 n/m2 (E > 0.1 MeV), which were pronounced at high dose and due to the very high thermal neutron flux of HFIR. Although the irradiation hardening mainly caused by defects clusters in a low dose regime, the transmutation-induced precipitation appeared to impose additional significant hardening of the tungsten.

  16. The knee in the cosmic ray energy spectrum from the simultaneous EAS charged particles and muon density spectra

    NASA Astrophysics Data System (ADS)

    Bijay, Biplab; Banik, Prabir; Bhadra, Arunava

    2016-09-01

    In this work we examine with the help of Monte Carlo simulation whether a consistent primary energy spectrum of cosmic rays emerges from both the experimentally observed total charged particles and muon size spectra of cosmic ray extensive air showers considering primary composition may or may not change beyond the knee of the energy spectrum. It is found that EAS-TOP observations consistently infer a knee in the primary energy spectrum provided the primary is pure unchanging iron whereas no consistent primary spectrum emerges from simultaneous use of the KASCADE observed total charged particle and muon spectra. However, it is also found that when primary composition changes across the knee the estimation of spectral index of total charged particle spectrum is quite tricky, depends on the choice of selection of points near the knee in the size spectrum.

  17. The self-energies and bosonic spectrum of high Tc cuprate from laser-based ARPES

    NASA Astrophysics Data System (ADS)

    Bok, Jin Mo; Bae, Jong Ju; Choi, Han-Yong; Yu, Li; Zhou, X. J.; Varma, Chandra M.

    While phonon mediated conventional superconductors are revealed by comparing tunneling and neutron scattering experiment, high Tc cuprate which has d-wave symmetry is still in debate. Laser-based AREPS can provide both momentum and energy dependence of spectral function that enables self-energy extraction using one particle Green's function. It is well known that anisotropy of electronic structure and d-wave superconducting gap on ARPES experiments. We analyzed high resolution APRES data of under and overdoped Bi2212 and extracted both normal and pairing self-energy. Here we report the extracted normal and pairing self-energy in supercondcuting state. Also we obtained bosonic spectrum from both self-energies by performing maximum entropy method. Implications of these results for understanding the superconductivity mechanism will be discussed.

  18. Cosmic ray energy spectrum around the knee obtained by the Tibet Experiment and future prospects

    NASA Astrophysics Data System (ADS)

    Katayose, Yusaku

    The measurement of the energy spectrum and the chemical composition of cosmic rays at the 'Knee' energy region have been made in the Tibet-AS experiment since 1990. The 1st phase of the Tibet hybrid experiment(1996-1999) consisted of Tibet II air-shower array(AS), Emulsion Chamber(EC) and burst detector(BD). The EC was used to detect high energy-gamma-families of the energy greater than 20 TeV at the core of ASs of which more than 80% are induced by light nuclei like protons or helium. Due to the high spatial resolution of the EC, proton and helium events were separated from others and we obtained the energy spectrum of each of them using 177 family events. We also obtained all-particle energy spectrum of primary cosmic rays in a wide range from 1014 eV to 1017 eV by the Tibet-III air-shower array. The size spectrum exhibits a sharp knee at a corresponding primary energy around 4 PeV. These results strongly indicated that the fraction of the light component to the all particle spectrum is decreasing around the knee.The observation of the AS core has been continued with upgraded Tibet III array and burst detectors without using X-ray films, which still works as the selector for the air showers induced by light component (pHe). This second phase experiment shows that the dominance of the heavy elements at the knee reported by the first phase experiment is confirmed with higher statistics by one order.Our results suggest that the main component at the knee is heavy elements (heavier than helium) because of the low intensities of observed proton and helium fluxes, whose summed flux are less than 30% of all particles. A new air-shower-core detector(YAC) will be added to the Tibet AS array to explicitly measure the heavy elements around the knee and beyond. In this paper, the results of composition study with the Tibet experiment are summarized and the prospects for the next phase experiment are described.

  19. Magnetic diffusion effects on the ultra-high energy cosmic ray spectrum and composition

    SciTech Connect

    Mollerach, Silvia; Roulet, Esteban E-mail: roulet@cab.cnea.gov.ar

    2013-10-01

    We discuss the effects of diffusion of high energy cosmic rays in turbulent extra-galactic magnetic fields. We find an approximate expression for the low energy suppression of the spectrum of the different mass components (with charge Z) in the case in which this suppression happens at energies below ∼ Z EeV, so that energy losses are dominated by the adiabatic ones. The low energy suppression appears when cosmic rays from the closest sources take a time comparable to the age of the Universe to reach the Earth. This occurs for energies E < Z EeV (B/nG)√(l{sub c}/Mpc)(d{sub s}/70Mpc) in terms of the magnetic field RMS strength B, its coherence length l{sub c} and the typical separation between sources d{sub s}. We apply this to scenarios in which the sources produce a mixed composition and have a relatively low maximum rigidity (E{sub max} ∼ (2–10)Z EeV), finding that diffusion has a significant effect on the resulting spectrum, the average mass and on its spread, in particular reducing this last one. For reasonable values of B and l{sub c} these effects can help to reproduce the composition trends observed by the Auger Collaboration for source spectra compatible with Fermi acceleration.

  20. Microstructural evolution of pure tungsten neutron irradiated with a mixed energy spectrum

    NASA Astrophysics Data System (ADS)

    Koyanagi, Takaaki; Kumar, N. A. P. Kiran; Hwang, Taehyun; Garrison, Lauren M.; Hu, Xunxiang; Snead, Lance L.; Katoh, Yutai

    2017-07-01

    Microstructures of single-crystal bulk tungsten (W) and polycrystalline W foil with a strong grain texture were investigated using transmission electron microscopy following neutron irradiation at ∼90-800 °C to 0.03-4.6 displacements per atom (dpa) in the High Flux Isotope Reactor with a mixed energy spectrum. The dominant irradiation defects were dislocation loops and small clusters at ∼90 °C. Additional voids were formed in W irradiated at above 460 °C. Voids and precipitates involving transmutation rhenium and osmium were the dominant defects at more than ∼1 dpa. We found a new phenomenon of microstructural evolution in irradiated polycrystalline W: Re- and Os-rich precipitation along grain boundaries. Comparison of results between this study and previous studies using different irradiation facilities revealed that the microstructural evolution of pure W is highly dependent on the neutron energy spectrum in addition to the irradiation temperature and dose.

  1. A quantum algorithm for obtaining the energy spectrum of a physical system without guessing its eigenstates.

    PubMed

    Wang, Hefeng

    2014-08-14

    We present a quantum algorithm that provides a general approach for obtaining the energy spectrum of a physical system without making a guess on its eigenstates. In this algorithm, a probe qubit is coupled to a quantum register R which consists of one ancilla qubit and an n-qubit register that represents the system. R is prepared in a general reference state, and a general excitation operator that acts on R is constructed. The probe exhibits a dynamical response only when it is resonant with a transition from the reference state to an excited state of R which contains the eigenstates of the system. By varying the probe's frequency, the energy spectrum and the eigenstates of the system can be obtained.

  2. Laser-stimulated modification of the impurity energy spectrum of gallium selenide intercalated with cobalt

    SciTech Connect

    Grygorchak, I. I. Pelekhovych, A. I.; Volynskaya, N. V.

    2008-04-15

    The effect of laser radiation on the impurity energy spectrum of intercalated structures is studied by the example of {sub 0.015}GaSe. By the variations in frequency dependences of resistivity measured normally to the layers of the obtained structure and by the transformation of the Nyquist diagrams consisting of two connected in series parallel R -parallel C units, a conclusion is made on the laser-stimulated compensation of the intercalant. The obtained values of the real part of permittivity are characteristic of doped semiconductors or their alloys in the radio-frequency range. The experimental results showed that the pulsed laser irradiation is an effective method to affect the energy impurity spectrum of intercalated compounds.

  3. 18 CFR 381.304 - Review of Department of Energy denial of adjustment.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... adjustment request under subpart J of the Commission's Rules of Practice and Procedure, 18 CFR part 385... Federal Register citations affecting § 381.304, see the List of CFR Sections Affected, which appears...

  4. The GCR All-Particle Spectrum in the 0.1-100 TeV Energy Range

    NASA Astrophysics Data System (ADS)

    Tolstaya, Ekaterina D.; Grigorov, N. L.

    2003-07-01

    The results of direct measurements of the all particle spectra by five different instruments on satellites and balloons are considered. It is shown, that is the representatio as the flux multiplied by energy to the power of 2.6 the all-particle spectrum shows a 'step'. The parameters of this 'step' and its origin are analyzed. Historically it has so happ ened that the all-particle spectrum obtained as the sum individual components, the energy range 1 < E < (5 - 10) TeV in the proton spectrum is not covered by direct measurements. Usually this energy interval in the all-particle spectrum is filled via interp olation, which is bases on the assumption that the proton spectrum is similar to the spectrum of nuclei. This spectrum is usually considered to be the all-particle GCR spectrum Io (E ) [1]. Direct information on the all-particle spectrum in the energy range from 1 to 10 TeV can be obtained using direct measurements of the of the all-particle spectrum by electronic instruments. For the first time such information was obtained in 1972 as a result of the all-particle spectrum measurements by the SEZ-14 instrument on the 'Proton1,2,3' satellites and the SEZ-15 instrument on the 'Proton-4' satellite [2,3]. These measurements revealed an anomaly in the all-particle spectrum in the 1-10 TeV energy range. In 1997 the spectrum was measured again by the TIC instrument [4]. The TIC instrument measured the energy release of all-particles arriving from arbitrary directions. As it was shown by the authors in [4,5] the energy release spectrum revealed the same anomaly in the all-particle spectrum, previously observed in the measurements made on 'Proton' satellites [2]. The results of the measurements made by the TIC, SEZ-14 and SEZ-15 are shown in Fig.1. The solid line in Fig.1 shows the function Φ(E ), which gives a good approximation of the experimental all-particle spectrum at a =0.4 TeV. Φ(E ) = E 2.6 Io (E ) (E /a)3 0.11 } + 0.130m-2s-1 sr -1 T eV 1.6 (1) {1 + 0.37 = [1

  5. The hybrid energy spectrum of Telescope Array's Middle Drum Detector and surface array

    NASA Astrophysics Data System (ADS)

    Abbasi, R. U.; Abe, M.; Abu-Zayyad, T.; Allen, M. G.; Anderson, R.; Azuma, R.; Barcikowski, E.; Belz, J. W.; Bergman, D. R.; Blake, S. A.; Cady, R.; Chae, M. J.; Cheon, B. G.; Chiba, J.; Chikawa, M.; Cho, W. R.; Fujii, T.; Fukushima, M.; Goto, T.; Hanlon, W.; Hayashi, Y.; Hayashida, N.; Hibino, K.; Honda, K.; Ikeda, D.; Inoue, N.; Ishii, T.; Ishimori, R.; Ito, H.; Ivanov, D.; Jui, C. C. H.; Kadota, K.; Kakimoto, F.; Kalashev, O.; Kasahara, K.; Kawai, H.; Kawakami, S.; Kawana, S.; Kawata, K.; Kido, E.; Kim, H. B.; Kim, J. H.; Kim, J. H.; Kitamura, S.; Kitamura, Y.; Kuzmin, V.; Kwon, Y. J.; Lan, J.; Lim, S. I.; Lundquist, J. P.; Machida, K.; Martens, K.; Matsuda, T.; Matsuyama, T.; Matthews, J. N.; Minamino, M.; Mukai, K.; Myers, I.; Nagasawa, K.; Nagataki, S.; Nakamura, T.; Nonaka, T.; Nozato, A.; Ogio, S.; Ogura, J.; Ohnishi, M.; Ohoka, H.; Oki, K.; Okuda, T.; Ono, M.; Oshima, A.; Ozawa, S.; Park, I. H.; Pshirkov, M. S.; Rodriguez, D. C.; Rubtsov, G.; Ryu, D.; Sagawa, H.; Sakurai, N.; Sampson, A. L.; Scott, L. M.; Shah, P. D.; Shibata, F.; Shibata, T.; Shimodaira, H.; Shin, B. K.; Shin, H. S.; Smith, J. D.; Sokolsky, P.; Springer, R. W.; Stokes, B. T.; Stratton, S. R.; Stroman, T. A.; Suzawa, T.; Takamura, M.; Takeda, M.; Takeishi, R.; Taketa, A.; Takita, M.; Tameda, Y.; Tanaka, H.; Tanaka, K.; Tanaka, M.; Thomas, S. B.; Thomson, G. B.; Tinyakov, P.; Tkachev, I.; Tokuno, H.; Tomida, T.; Troitsky, S.; Tsunesada, Y.; Tsutsumi, K.; Uchihori, Y.; Udo, S.; Urban, F.; Vasiloff, G.; Wong, T.; Yamane, R.; Yamaoka, H.; Yamazaki, K.; Yang, J.; Yashiro, K.; Yoneda, Y.; Yoshida, S.; Yoshii, H.; Zollinger, R.; Zundel, Z.

    2015-08-01

    The Telescope Array experiment studies ultra high energy cosmic rays using a hybrid detector. Fluorescence telescopes measure the longitudinal development of the extensive air shower generated when a primary cosmic ray particle interacts with the atmosphere. Meanwhile, scintillator detectors measure the lateral distribution of secondary shower particles that hit the ground. The Middle Drum (MD) fluorescence telescope station consists of 14 telescopes from the High Resolution Fly's Eye (HiRes) experiment, providing a direct link back to the HiRes measurements. Using the scintillator detector data in conjunction with the telescope data improves the geometrical reconstruction of the showers significantly, and hence, provides a more accurate reconstruction of the energy of the primary particle. The Middle Drum hybrid spectrum is presented and compared to that measured by the Middle Drum station in monocular mode. Further, the hybrid data establishes a link between the Middle Drum data and the surface array. A comparison between the Middle Drum hybrid energy spectrum and scintillator Surface Detector (SD) spectrum is also shown.

  6. The Spectrum of Ultrahigh Energy Cosmic Rays and Constraints on Lorentz Invariance Violation

    NASA Technical Reports Server (NTRS)

    Stecker, F. W.

    2008-01-01

    There has been much interest in possible violations of Lorentz invariance, particularly motivated by quantum gravity theories. It has been suggested that a small amount of Lorentz invariance violation (LIV) could turn off photomeson interactions of ultrahigh energy cosmic rays (UHECRs) with photons of the cosmic background radiation and thereby eliminate the resulting sharp steepening in the spectrum of the highest energy CRs predicted by Greisen Zatsepin and Kuzmin (GZK). Recent measurements of the UHECR spectrum reported by the HiRes and Auger collaborations, however, indicate the presence of the GZK effect. We present the results of a detailed calculation of the modification of the UHECR spectrum caused by LIV using the formalism of Coleman and Glashow. We then use a chi-squared analysis to compare our results with the experimental UHECR data and thereby place limits on the amount of LIV. We also discuss how a small amount of LIV that is consistent with the experimental data can still lead to a recovery of the cosmic ray flux at higher energies than presently observed.

  7. Peculiarities of the electron energy spectrum in the Coulomb field of a superheavy nucleus

    NASA Astrophysics Data System (ADS)

    Voronov, B. L.; Gitman, D. M.; Levin, A. D.; Ferreira, R.

    2016-05-01

    We consider the peculiarities of the electron energy spectrum in the Coulomb field of a superheavy nucleus and discuss the long history of an incorrect interpretation of this problem in the case of a pointlike nucleus and its current correct solution. We consider the spectral problem in the case of a regularized Coulomb potential. For some special regularizations, we derive an exact equation for the point spectrum in the energy interval (-m,m) and find some of its solutions numerically. We also derive an exact equation for charges yielding bound states with the energy E = -m; some call them supercritical charges. We show the existence of an infinite number of such charges. Their existence does not mean that the oneparticle relativistic quantum mechanics based on the Dirac Hamiltonian with the Coulomb field of such charges is mathematically inconsistent, although it is physically unacceptable because the spectrum of the Hamiltonian is unbounded from below. The question of constructing a consistent nonperturbative second-quantized theory remains open, and the consequences of the existence of supercritical charges from the standpoint of the possibility of constructing such a theory also remain unclear.

  8. Observations of low-energy /0.3- to 1.8-MeV/ differential spectrums of trapped protons.

    NASA Technical Reports Server (NTRS)

    Venkatesan, D.; Krimigis, S. M.

    1971-01-01

    Measurements of differential energy spectrums of trapped protons obtained from several passes during the period January to November 1969 using the polar orbiting, low-altitude Injun 5 satellite equipped with a special solid-state detector proton-electron telescope are presented. Results reveal the existence of a quasi-persistent peak in the differential energy spectrum in the McIlwain shell parameter (L) range 2 to 2.6 and in the energy range of approximately 0.32 to 0.72 MeV. The fact that the shape of the spectrum is stable for several days or can change with time scales as small as 4 hours suggests an impulsive acceleration mechanism deep in the radiation belts. Other features of the spectrum show that if the spectrum is represented by an exponential form in energy, the dependence of the spectral parameter is in general agreement with diffusion theory over the L range of approximately 2 to 4.

  9. VERIFICATION OF THE INL/COMBINE7 NEUTRON ENERGY SPECTRUM CODE

    SciTech Connect

    Barry D. Ganapol; Woo Y. Yoon; David W. Nigg

    2008-09-01

    We construct semi-analytic benchmarks for the neutron slowing down equations in the thermal, resonance and fast energy regimes through mathematical embedding. The method features a fictitious time-dependent slowing down equations solved via Taylor series expansion over discrete “time” intervals. Two classes of benchmarks are considered- the first treats methods of solution and the second the multigroup approximation itself. We present several meaningful benchmark methods comparisons with the COMBINE7 energy spectrum code and a simple demonstration of convergence of the multigroup approximation.

  10. A statistical iterative reconstruction framework for dual energy computed tomography without knowing tube spectrum

    NASA Astrophysics Data System (ADS)

    Chang, Shaojie; Mou, Xuanqin

    2016-09-01

    Dual energy computed tomography (DECT) has significant impacts on material characterization, bone mineral density inspection, nondestructive evaluation and so on. In spite of great progress has been made recently on reconstruction algorithms for DECT, there still exist two main problems: 1) For polyenergetic X-ray source, the tube spectrum needed in reconstruction is not always available. 2) The reconstructed image of DECT is very sensitive to noise which demands special noise suppression strategy in reconstruction algorithm design. In this paper, we propose a novel method for DECT reconstruction that reconstructs tube spectrum from projection data and suppresses image noise by introducing l1-norm based regularization into statistical reconstruction for polychromatic DECT. The contribution of this work is twofold. 1) A three parameters model is devised to represent spectrum of ployenergetic X-ray source. And the parameters can be estimated from projection data by solving an optimization problem. 2) With the estimated tube spectrum, we propose a computation framework of l1-norm regularization based statistical iterative reconstruction for polychromatic DECT. Simulation experiments with two phantoms were conducted to evaluate the proposed method. Experimental results demonstrate the accuracy and robustness of the spectrum model in terms of that comparable reconstruction image quality can be achieved with the estimated and ideal spectrum, and validate that the proposed method works with attractive performance in terms of accuracy of reconstructed image. The root mean square error (RMSE) between the reconstructed image and the ground truth image are 7.648 × 10-4 and 2.687 x 10-4 for the two phantoms, respectively.

  11. Measurements of the energy spectrum of electrons emanating from solid materials irradiated by a picosecond laser

    SciTech Connect

    Di Stefano, C. A.; Kuranz, C. C.; Seely, J. F.; Thomas, A. G. R.; Drake, R. P.; Keiter, P. A.; Williams, G. J.; Park, J.; Chen, H.; MacDonald, M. J.; Rasmus, A. M.; Wan, W. C.; Pereira, N. R.; Joglekar, A. S.; McKelvey, A.; Zhao, Z.; Klein, S. R.; Kemp, G. E.; Jarrott, L. C.; Krauland, C. M.; Peebles, J.; Westover, B.

    2015-04-01

    Here, we present the results of experiments observing the properties of the electron stream generated laterally when a laser irradiates a metal. We also found that the directionality of the electrons is dependent upon their energies, with the higher-energy tail of the spectrum ( 1MeV and higher) being more narrowly focused. This behavior is likely due to the coupling of the electrons to the electric field of the laser. We performed these experiments by using the Titan laser to irradiate a metal wire, creating the electron stream of interest. These electrons propagate to nearby spectator wires of differing metals, causing them to fluoresce at their characteristic K-shell energies. This fluorescence is recorded by a crystal spectrometer. By varying the distances between the wires, we are able to probe the divergence of the electron stream, while by varying the medium through which the electrons propagate (and hence the energy-dependence of electron attenuation), we are able to probe the energy spectrum of the stream.

  12. THE COSMIC-RAY ENERGY SPECTRUM OBSERVED WITH THE SURFACE DETECTOR OF THE TELESCOPE ARRAY EXPERIMENT

    SciTech Connect

    Abu-Zayyad, T.; Allen, M.; Anderson, R.; Barcikowski, E.; Belz, J. W.; Bergman, D. R.; Blake, S. A.; Cady, R.; Hanlon, W.; Aida, R.; Azuma, R.; Fukuda, T.; Cheon, B. G.; Cho, E. J.; Chiba, J.; Chikawa, M.; Cho, W. R.; Fujii, H.; Fujii, T.; Fukushima, M.; and others

    2013-05-01

    The Telescope Array (TA) collaboration has measured the energy spectrum of ultra-high energy cosmic rays (UHECRs) with primary energies above 1.6 Multiplication-Sign 10{sup 18} eV. This measurement is based upon four years of observation by the surface detector component of TA. The spectrum shows a dip at an energy of 4.6 Multiplication-Sign 10{sup 18} eV and a steepening at 5.4 Multiplication-Sign 10{sup 19} eV which is consistent with the expectation from the GZK cutoff. We present the results of a technique, new to the analysis of UHECR surface detector data, that involves generating a complete simulation of UHECRs striking the TA surface detector. The procedure starts with shower simulations using the CORSIKA Monte Carlo program where we have solved the problems caused by use of the ''thinning'' approximation. This simulation method allows us to make an accurate calculation of the acceptance of the detector for the energies concerned.

  13. Measurements of the energy spectrum of electrons emanating from solid materials irradiated by a picosecond laser

    DOE PAGES

    Di Stefano, C. A.; Kuranz, C. C.; Seely, J. F.; ...

    2015-04-01

    Here, we present the results of experiments observing the properties of the electron stream generated laterally when a laser irradiates a metal. We also found that the directionality of the electrons is dependent upon their energies, with the higher-energy tail of the spectrum ( 1MeV and higher) being more narrowly focused. This behavior is likely due to the coupling of the electrons to the electric field of the laser. We performed these experiments by using the Titan laser to irradiate a metal wire, creating the electron stream of interest. These electrons propagate to nearby spectator wires of differing metals, causingmore » them to fluoresce at their characteristic K-shell energies. This fluorescence is recorded by a crystal spectrometer. By varying the distances between the wires, we are able to probe the divergence of the electron stream, while by varying the medium through which the electrons propagate (and hence the energy-dependence of electron attenuation), we are able to probe the energy spectrum of the stream.« less

  14. Family function, Parenting Style and Broader Autism Phenotype as Predicting Factors of Psychological Adjustment in Typically Developing Siblings of Children with Autism Spectrum Disorders.

    PubMed

    Mohammadi, Mohammadreza; Zarafshan, Hadi

    2014-04-01

    Siblings of children with autism are at a greater risk of experiencing behavioral and social problems. Previous researches had focused on environmental variables such as family history of autism spectrum disorders (ASDs), behavior problems in the child with an ASD, parental mental health problems, stressful life events and "broader autism phenotype" (BAP), while variables like parenting style and family function that are shown to influence children's behavioral and psychosocial adjustment are overlooked. The aim of the present study was to reveal how parenting style and family function as well as BAP effect psychological adjustment of siblings of children with autism. The Participants included 65 parents who had one child with an Autism Spectrum Disorder and one typically developing child. Of the children with ASDs, 40 were boys and 25 were girls; and they were diagnosed with ASDs by a psychiatrist based on DSM-IV-TR criteria and Autism Diagnostic Interview-Revised (ADI-R). The Persian versions of the six scales were used to collect data from the families. Pearson's correlation test and regression analysis were used to determine which variables were related to the psychological adjustment of sibling of children with ASDs and which variables predicted it better. Significant relationships were found between Strengths and Difficulties Questionnaire (SDQ) total difficulties, prosocial behaviors and ASDs symptoms severity, parenting styles and some aspects of family function. In addition, siblings who had more BAP characteristics had more behavior problems and less prosocial behavior. Behavioral problems increased and prosocial behavior decreased with permissive parenting style. Besides, both of authoritarian and authoritative parenting styles led to a decrease in behavioral problems and an increase in prosocial behaviors. Our findings revealed that some aspects of family function (affective responsiveness, roles, problem solving and behavior control) were significantly

  15. Use of inverse time, adjustable instantaneous pickup circuit breakers for short circuit and ground fault protection of energy efficient motors

    SciTech Connect

    Heath, D.W.; Bradfield, H.L.

    1995-12-31

    Many energy efficient low voltage motors exhibit first half cycle instantaneous inrush current values greater than the National Electrical Code`s 13 times motor full load amperes maximum permissible setting for instantaneous trip circuit breakers. The alternate use of an inverse time circuit breaker could lead to inadequate protection if the breaker does not have adjustable instantaneous settings. Recent innovations in digital solid state trip unit technology have made available an inverse time, adjustable instantaneous trip circuit breaker in 15A to 150A ratings. This allows the instantaneous pickup to be adjusted to a value slightly above motor inrush so that low level faults will be cleared instantaneously while avoiding nuisance tripping at startup. Applications, settings and comparisons are discussed.

  16. An approach to an accurate determination of the energy spectrum of high-energy electron beams using magnetic spectrometry

    NASA Astrophysics Data System (ADS)

    Renner, F.; Schwab, A.; Kapsch, R.-P.; Makowski, Ch; Jannek, D.

    2014-03-01

    At the national metrology institute of Germany, the Physikalisch-Technische Bundesanstalt, a research accelerator for dosimetry in radiation therapy has been installed. Magnetic spectrometry is used to determine the spectrum of high-energy electrons generated by this accelerator. Regarding the intended experiments at the accelerator, a high accuracy for the energy determination of the electron beam is required. For this purpose, an experimental setup is used that has a number of additional devices assembled around the spectrometer to determine geometric characteristics of the electron beam, which influence the energy analysis. For the analysis of the acquired data, a software was developed which meets specific needs. One important aspect is that the software is based on an algorithm for energy determination which considers the measured magnetic flux density of the spectrometer and geometric details of the beam and the spectrometer. The software also meets the demand that it can be used to estimate the uncertainty assigned to the energy. This paper covers the experimental and analytical background of magnetic spectrometry at the high-energy beamline of PTB's research accelerator. A comparison of results calculated with the specific algorithm for energy determination which was developed for this experimental setup and with well-known algorithms is given to show the advantage of the specific method. Results of measurements and their analysis with the algorithm are presented as well.

  17. The spectrum of cosmic electron with energies between 6 and 100 GeV

    NASA Technical Reports Server (NTRS)

    Meegan, C. A.; Earl, J. A.

    1974-01-01

    This experiment was carried out during three balloon flights which provided a total exposure of 3500 + or - 60 sq m sec sterad at an average depth of 4.8 g/sq cm The detector, in which the development of cascade showers in a 33.7 rl absorber was sampled by 10 scintillation counters and 216 Geiger-Muller tubes, was calibrated at the Cornell Electron Synchrotron, the separation of cosmic electrons from the nuclear background was confirmed by extensive analysis of data from the flights, from the calibration and from ground level exposure. The spectral intensity of primary cosmic ray electrons were found in particles/sq m sec sterad GeV. Similarly, the ground level spectrum of secondary cosmic ray electrons was also found. The steepness of the spectrum of cosmic electrons relative to that of nuclei implies one of the following conclusions: either the injection spectrum of electrons is steeper than that of nuclei, or the electron spectrum has been steepened by Compton/synchrotron losses in the energy range covered by the experiment.

  18. Advantages of Real-Time Spectrum Analyzers in High-Energy Physics Applications

    NASA Astrophysics Data System (ADS)

    Parker, Louis

    2004-11-01

    Typically, particles are injected into the ring at low energy levels and then "ramped up" to higher levels. During ramping, it is important that the horizontal and vertical tune frequencies do not shift, lest they hit upon a resonant combination that causes beam instability or sudden total loss of ring beam current (beam blow up). Beam instabilities can be caused by a number of factors. Non-linearities and/or different response times of independent controls such as beam position monitor (BPM) cables and circuits, magnets for guidance and focusing of the beam, Klystrons or Tetrodes (which provide power to RF cavities that transmit energy to the beam), and vacuum pumps and monitors can all cause beam instabilities. Vibrations and lack of proper shielding are other factors. The challenge for operators and researchers is to correctly identify the factors causing beam instabilities and blow up so that costly accelerator time is not interrupted and experimental results are not compromised. The instrument often used to identify problems in particle accelerator applications is the spectrum analyzer. This paper will discuss the advantages of real time spectrum analyzers (RSA) versus swept frequency spectrum analyzers in HEP applications. The main focus will be on monitoring beam position and stability, especially during ramp-up. Also covered will be use of RSA for chromaticity measurements, Phase Locked Loop (PLL) diagnostics, and vibration analysis.

  19. A multiple-time-scale turbulence model based on variable partitioning of turbulent kinetic energy spectrum

    NASA Technical Reports Server (NTRS)

    Kim, S.-W.; Chen, C.-P.

    1987-01-01

    A multiple-time-scale turbulence model of a single point closure and a simplified split-spectrum method is presented. In the model, the effect of the ratio of the production rate to the dissipation rate on eddy viscosity is modeled by use of the multiple-time-scales and a variable partitioning of the turbulent kinetic energy spectrum. The concept of a variable partitioning of the turbulent kinetic energy spectrum and the rest of the model details are based on the previously reported algebraic stress turbulence model. Example problems considered include: a fully developed channel flow, a plane jet exhausting into a moving stream, a wall jet flow, and a weakly coupled wake-boundary layer interaction flow. The computational results compared favorably with those obtained by using the algebraic stress turbulence model as well as experimental data. The present turbulence model, as well as the algebraic stress turbulence model, yielded significantly improved computational results for the complex turbulent boundary layer flows, such as the wall jet flow and the wake boundary layer interaction flow, compared with available computational results obtained by using the standard kappa-epsilon turbulence model.

  20. Weak turbulant theory estimation for non-linear energy, wave action and momentum fluxes in wind wave spectrum

    NASA Astrophysics Data System (ADS)

    Lavrenov, I.

    2003-04-01

    Direct numerical simulations of the Hasselmann kinetic equation for gravity waves in water surface confirms basic predictions of the weak-turbulent theory. Three different stages can be defined in the wave spectrum evolution.. At the first stage the spectrum unstable growth is observed within the range of the external force input. High frequency spectrum development is observed at the second stage of spectrum evolution. The frequency spectrum is becoming larger within high frequency range and a spectral growth is penetrated to a larger frequency range. After that the spectrum remains almost constant at high frequency range. In both isotropic and non-isotropic cases the spectra are found out to be close to the Zakharov-Filonenko spectrum pow(w,-4) not only in the universal range, but in the range of wave energy input. Formation of this asymptotic spectrum happens explosively. The third stage of spectrum evolution is revealed for a larger time period. It is characterized by a slow spectrum evolution into a low frequency range. The spectrum value becomes larger penetrating to a smaller frequency range with decreasing speed in accordance with experimental data. In low frequency range a power spectrum is revealed for both isotropic and non-isotropic cases with the spectra close to the Zakharov-Zaslavskii spectrum pow(w,-11/3). Main energy flux is directed to the high frequency range. Its value makes up 77 per cent of total value of wave energy input coming from external source. Main wave action flux is directed to low frequency range. Its relative value is equal to 75 per cents of total wave action flux input. 25 per cents of wave action is directed to high frequency range. Almost all wave momentum (up to 98 per cents) is directed to high frequency range. The investigations are supported by the Grants: RFBR 01-05-64846, and INTAS-(99)-666, INTAS - (01)-234, INTAS-(01)-2156.

  1. Monocular measurement of the ultra-high energy cosmic ray spectrum

    NASA Astrophysics Data System (ADS)

    Shah, Priti Dhanesh

    The Telescope Array Project was designed to observe cosmic rays with energies greater than 1018 eV. Its goals are to study the physics of cosmic rays by measuring their anisotropy, composition, and energy spectrum. This work makes a monocular measurement of the ultra high energy cosmic ray spectrum and analyzes the physics produced from that spectrum. The flux of cosmic rays observed on Earth follows a power law over 12 decades in energy and 32 decades in flux. At the highest energies, the spectrum has detailed structure. Studying these features can tell us about the astrophysics of the production and propagation of cosmic rays. First, it can tell us about the sources of cosmic rays such as they capable of producing a power law spectrum and the maximum energy of cosmic rays that they can produce. Second, the acceleration mechanisms that can boost cosmic rays to ultra high energies can be studied. Third, the spectral features themselves can tell us about their possible cause for formation. For example, the ankle feature in the ultra high energy regime can tell us if it is the galactic-extragalactic transition or if it is due to e+e- pair production. Fourth, the energy losses that cosmic rays incur can tell us about their physical interactions during propagation. Studying the physics of the cosmic ray spectrum in the ultra high energy regime with data from the Telescope Array Project is the goal of this analysis. The Telescope Array Project consists of three fluorescence detectors overlooking an array of 507 scintillation surface detectors. Due to their extremely low flux at these energies, cosmic rays can only be observed indirectly via an extensive air shower produced when they collide with the nucleus of an atom in the Earth's atmosphere. These charged secondary particles produce fluorescence light. The array of surface detectors observes the lateral footprint of the extensive air shower when it reaches the ground. The fluorescence detectors observe the

  2. The energy spectrum of ultra-high-energy cosmic rays measured by the Telescope Array FADC fluorescence detectors in monocular mode

    NASA Astrophysics Data System (ADS)

    Abu-Zayyad, T.; Aida, R.; Allen, M.; Anderson, R.; Azuma, R.; Barcikowski, E.; Belz, J. W.; Bergman, D. R.; Blake, S. A.; Cady, R.; Cheon, B. G.; Chiba, J.; Chikawa, M.; Cho, E. J.; Cho, W. R.; Fujii, H.; Fujii, T.; Fukuda, T.; Fukushima, M.; Hanlon, W.; Hayashi, K.; Hayashi, Y.; Hayashida, N.; Hibino, K.; Hiyama, K.; Honda, K.; Iguchi, T.; Ikeda, D.; Ikuta, K.; Inoue, N.; Ishii, T.; Ishimori, R.; Ito, H.; Ivanov, D.; Iwamoto, S.; Jui, C. C. H.; Kadota, K.; Kakimoto, F.; Kalashev, O.; Kanbe, T.; Kasahara, K.; Kawai, H.; Kawakami, S.; Kawana, S.; Kido, E.; Kim, H. B.; Kim, H. K.; Kim, J. H.; Kim, J. H.; Kitamoto, K.; Kitamura, S.; Kitamura, Y.; Kobayashi, K.; Kobayashi, Y.; Kondo, Y.; Kuramoto, K.; Kuzmin, V.; Kwon, Y. J.; Lan, J.; Lim, S. I.; Lundquist, J. P.; Machida, S.; Martens, K.; Matsuda, T.; Matsuura, T.; Matsuyama, T.; Matthews, J. N.; Myers, I.; Minamino, M.; Miyata, K.; Murano, Y.; Nagataki, S.; Nakamura, T.; Nam, S. W.; Nonaka, T.; Ogio, S.; Ogura, J.; Ohnishi, M.; Ohoka, H.; Oki, K.; Oku, D.; Okuda, T.; Ono, M.; Oshima, A.; Ozawa, S.; Park, I. H.; Pshirkov, M. S.; Rodriguez, D. C.; Roh, S. Y.; Rubtsov, G.; Ryu, D.; Sagawa, H.; Sakurai, N.; Sampson, A. L.; Scott, L. M.; Shah, P. D.; Shibata, F.; Shibata, T.; Shimodaira, H.; Shin, B. K.; Shin, J. I.; Shirahama, T.; Smith, J. D.; Sokolsky, P.; Sonley, T. J.; Springer, R. W.; Stokes, B. T.; Stratton, S. R.; Stroman, T. A.; Suzuki, S.; Takahashi, Y.; Takeda, M.; Taketa, A.; Takita, M.; Tameda, Y.; Tanaka, H.; Tanaka, K.; Tanaka, M.; Thomas, S. B.; Thomson, G. B.; Tinyakov, P.; Tkachev, I.; Tokuno, H.; Tomida, T.; Troitsky, S.; Tsunesada, Y.; Tsutsumi, K.; Tsuyuguchi, Y.; Uchihori, Y.; Udo, S.; Ukai, H.; Vasiloff, G.; Wada, Y.; Wong, T.; Yamakawa, Y.; Yamane, R.; Yamaoka, H.; Yamazaki, K.; Yang, J.; Yoneda, Y.; Yoshida, S.; Yoshii, H.; Zollinger, R.; Zundel, Z.

    2013-08-01

    We present a measurement of the energy spectrum of ultra-high-energy cosmic rays performed by the Telescope Array experiment using monocular observations from its two new FADC-based fluorescence detectors. After a short description of the experiment, we describe the data analysis and event reconstruction procedures. Since the aperture of the experiment must be calculated by Monte Carlo simulation, we describe this calculation and the comparisons of simulated and real data used to verify the validity of the aperture calculation. Finally, we present the energy spectrum calculated from the merged monocular data sets of the two FADC-based detectors, and also the combination of this merged spectrum with an independent, previously published monocular spectrum measurement performed by Telescope Array's third fluorescence detector [T. Abu-Zayyad et al., The energy spectrum of Telescope Array's middle drum detector and the direct comparison to the high resolution fly's eye experiment, Astroparticle Physics 39 (2012) 109-119, http://dx.doi.org/10.1016/j.astropartphys.2012.05.012, Available from: ]. This combined spectrum corroborates the recently published Telescope Array surface detector spectrum [T. Abu-Zayyad, et al., The cosmic-ray energy spectrum observed with the surface detector of the Telescope Array experiment, ApJ 768 (2013) L1, http://dx.doi.org/10.1088/2041-8205/768/1/L1, Available from: ] with independent systematic uncertainties.

  3. Reconstruction of the Primary Energy Spectrum from Fluorescence Telescope Data of the Pierre Auger Observatory

    NASA Astrophysics Data System (ADS)

    Geenen, H.

    2007-07-01

    The Pierre Auger Observatory is the largest extensive air-shower (EAS) experiment in operation. It is still being constructed, and the final configuration will have detectors at the two sites Argentina and USA observing both celestial hemispheres. The aim of the experiment is to determine the energy, composition and origin of ultra-high energy cosmic-rays (UHECR) using two complementary detection techniques. The detector at the southern site presently contains more than 1400 (Jul. 2007) water-Cherenkov detectors at ground level (870 gcm^-2). Completion of the 3000 km^2 large detector array is expected by the end of 2007 with finally more than 1600 tanks. The atmosphere above the site is observed by 24 fluorescence telescopes located in four buildings at the boundary of the array. During clear moon-less nights, this configuration permits hybrid measurement of both longitudinal development of an EAS and lateral particle density at ground. All fluorescence telescopes are fully operational since February 2007. The aim of this work is to reconstruct the cosmic ray energy spectrum between a few 10^17 eV up to 10^20 eV. This would provide an overlap to spectral results from other experiments at lower energies. The hybrid detection provides an accurate geometry determination and thereby a good energy resolution. However, the energy threshold is limited to the threshold of the surface array: larger than a few 10^18 eV. The advantage of FD-monocular events (FD-mono) is a lower energy threshold in the aimed 10^17 eV regime. In addition, the present FD-mono exposure is about 1.5 times larger than the hybrid one. However, the energy resolution of FD-mono events is worse compared to hybrid, and the detector acceptance is strongly energy dependent. Therefore, the determination of the energy spectrum requires an unfolding procedure, which considers both the limited acceptance and the limited resolution. In this analysis the FD-mono data are reconstructed. The reconstruction

  4. Measurement of the Solar Neutrino Energy Spectrum Using Neutrino-Electron Scattering

    SciTech Connect

    Fukuda, Y.; Hayakawa, T.; Ichihara, E.; Inoue, K.; Ishihara, K.; Ishino, H.; Itow, Y.; Kajita, T.; Kameda, J.; Kasuga, S.; Kobayashi, K.; Kobayashi, Y.; Koshio, Y.; Miura, M.; Nakahata, M.; Nakayama, S.; Okada, A.; Okumura, K.; Sakurai, N.; Shiozawa, M.; Suzuki, Y.; Takeuchi, Y.; .Totsuka, Y.; Yamada, S.; Earl, M.; Habig, A.; Kearns, E.; Messier, M.D.; Scholberg, K.; Stone, J.L.; Sulak, L.R.; Walter, C.; Goldhaber, M.; Barszczak, T.; Casper, D.; Gajewski, W.; Halverson, P.G.; Hsu, J.; Kropp, W.R.; Price, L.R.; Reines, F.; Smy, M.; Sobel, H.W.; Vagins, M.R.; Haines, T.J.; Kielczewska, D.; Ganezer, K.S.; Keig, W.E.; Ellsworth, R.W.; Tasaka, S.; Flanagan, J.W.; Kibayashi, A.; Learned, J.G.; Matsuno, S.; Stenger, V.J.; Takemori, D.; Ishii, T.; Kanzaki, J.; Kobayashi, T.; Mine, S.; Nakamura, K.; Nishikawa, K.; Oyama, Y.; Sakai, A.; Sakuda, M.; Sasaki, O.; Echigo, S.; Kohama, M.; Suzuki, A.T.; Haines, T.J.; and others

    1999-03-01

    A measurement of the energy spectrum of recoil electrons from solar neutrino scattering in the Super-Kamiokande detector is presented. The results shown here were obtained from 504 days of data taken between 31 May 1996 and 25 March 1998. The shape of the measured spectrum is compared with the expectation for solar {sup 8}B neutrinos. The comparison takes into account both kinematic and detector related effects in the measurement process. The spectral shape comparison between the observation and the expectation gives a {chi}{sup 2} of 25.3 with 15 degrees of freedom, corresponding to a 4.6{percent} confidence level. {copyright} {ital 1999} {ital The American Physical Society}

  5. Height-adjustable desks: Energy expenditure, liking, and preference of sitting and standing

    USDA-ARS?s Scientific Manuscript database

    Background: Sedentary occupations likely promote weight gain. Standing may be a passive means of increasing energy expenditure throughout the workday. The purpose was to determine the energy expenditure and liking of word processing while sitting and standing. Methods: Energy expenditure was measu...

  6. Energy spectrum of medium energy gamma-rays from the galactic center region. [experimental design

    NASA Technical Reports Server (NTRS)

    Palmeira, R. A. R.; Ramanujarao, K.; Dutra, S. L. G.; Bertsch, D. L.; Kniffen, D. A.; Morris, D. J.

    1978-01-01

    A balloon-borne magnetic core digitized spark chamber with two assemblies of spark-chambers above and below the scintillation counters was used to measure the medium energy gamma ray flux from the galactic center region. Gamma ray calculations are based on the multiple scattering of the pair electrons in 15 aluminum plates interleaved in the spark chamber modules. Counting rates determined during ascent and at ceiling indicate the presence of diffuse component in this energy range. Preliminary results give an integral flux between 15 and 70 MeV compared to the differential points in other results.

  7. The degree of misreporting of the energy-adjusted intake of protein, potassium, and sodium does not differ among under-, acceptable, and over-reporters of energy intake.

    PubMed

    Murakami, Kentaro; Sasaki, Satoshi; Uenishi, Kazuhiro

    2012-10-01

    It is unclear whether misreporting of nutrient intakes differs according to energy reporting status. We examined misreporting of dietary protein, potassium, and sodium in under-, acceptable, and over-reporters of energy intake. Our hypothesis was that degree of misreporting of these three nutrients differs among under-, acceptable, and over-reporters. Participants were 1043 Japanese women aged 18 to 22 years. Self-reported dietary intake was obtained using a diet history questionnaire. Under-, acceptable, and over-reporters of energy intake were identified based on the ratio of self-reported energy intake to estimated energy requirement (<0.70 [17.2%], 0.70-1.30 [78.1%], and >1.30 [4.7%], respectively). Misreporting of dietary protein, potassium, and sodium was assessed against the corresponding biomarker-based estimate derived from 24-hour urinary excretion. On average, the degree of misreporting of intake of energy and the three nutrients varied considerably. Absolute intake (amount per day) of the three nutrients was under-reported in under-reporters of energy intake and over-reported in over-reporters compared with acceptable reporters. However, mainly because of high correlations between the ratio of self-reported energy intake to estimated energy requirement and the ratio of self-reported to biomarker-based estimates of absolute intake of three nutrients (Pearson correlation coefficient: 0.64 for protein, 0.51 for potassium, and 0.37 for sodium), the degree of misreporting of the energy-adjusted intake of these nutrients based on the density method did not differ across categories of energy reporting status. In conclusion, these findings may lend support to the usefulness of adjustment for energy misreporting and the futility of merely excluding energy misreporters from analysis.

  8. Modulation of the Galactic Low-energy Proton Spectrum in the Inner Heliosphere

    NASA Astrophysics Data System (ADS)

    Kecskeméty, K.; Logachev, Yu. I.; Zeldovich, M. A.; Kóta, J.

    2011-09-01

    We study the energy spectra of 0.3-100 MeV protons and find that, at the lower part of the galactic particle spectrum, they are significantly steeper than the J(E) ~ E spectrum predicted by analytical approximations, such as the force-field model of modulation. We select a series of low-flux periods, and approximate the spectral form by J(E) = AE -γ + CE ν, where the two terms describe solar/heliospheric and galactic components, respectively. By determining the best fit parameters to energy spectra, correlations are sought with solar activity indices and between the parameters themselves. In the majority of cases, ν turns out to be between 1.2 and 1.4, with an average of 1.32 ± 0.12, significantly greater than the commonly expected ν = 1 predicted by the force-field approximation. In modulation theories ν > 1 corresponds to a negative Compton-Getting factor, which poses a challenge. Such an inversion may occur if the radial diffusion coefficient κrr < rV (where r is heliocentric distance and V solar wind speed), in which case a large fraction of the 10-100 MeV protons reaching 1 AU would have been cooled down within 1 AU and subsequently convected outward by the solar wind. We also find that the position of the intensity minimum of the proton spectrum dividing the solar and galactic populations shifts toward higher values with increasing solar activity. Correlations obtained with solar activity indicate that the slope of the solar/heliospheric spectrum is practically independent of solar activity. Observations are compared with numerical solutions of the modulation equation adopting simple spherical models. Possible interpretations are discussed.

  9. Wind cannot be Directed but Sails can be Adjusted for Malaysian Renewable Energy Progress

    NASA Astrophysics Data System (ADS)

    Palanichamy, C.; Nasir, Meseret; Veeramani, S.

    2015-04-01

    Wind energy has been the promising energy technology since 1980s in terms of percentage of yearly growth of installed capacity. However the progress of wind energy has not been evenly distributed around the world. Particularly, in South East Asian countries like Malaysia and Singapore, though the Governments are keen on promoting wind energy technology, it is not well practiced due to the low wind speeds. Owing to the recent advancements in wind turbine designs, even Malaysia is well suited for wind energy by proper choice of wind turbines. As evidence, this paper presents successful wind turbines with simulated study outcomes to encourage wind power developments in Malaysia.

  10. Classification of vibrational resonances in the energy spectrum of the formaldehyde molecule and Katz's branch points

    NASA Astrophysics Data System (ADS)

    Bykov, A. D.; Duchko, A. N.

    2016-05-01

    The Rayleigh-Schrödinger perturbation theory of high orders and the algebraic Padé-Hermite approximants are used to determine the singular points of a vibrational energy function of the formaldehyde molecule dependent on a complex perturbation parameter as on the argument. It is shown that the Fermi, Darling-Dennison, and other higher-order vibrational resonances are related to Katz's points—common branch points on the complex plane of the energy of two vibrational states. Analysis of Katz's points that connect different vibrational states allows one to reveal essential resonance perturbations, to introduce an additional classification for them, and to determine the polyad structure of an energy spectrum.

  11. Measurement of the top-quark mass from the b jet energy spectrum

    NASA Astrophysics Data System (ADS)

    Guerrero, Daniel; Compact Muon Solenoid (CMS) Collaboration

    2016-03-01

    A first measurement of the top-quark mass using only two body decay kinematics is presented. Based on a recent theoretical proposal, the mass extraction is carried out using the peak position of the energy distribution of b jets produced from top-quark decays. This analysis is performed selecting top-antitop events with electron-muon final states in proton-proton collision data at √{ s} = 8TeV with the CMS detector, corresponding to an integrated luminosity of 19.7 fb-1 . The energy peak position is obtained by fitting the observed energy spectrum. Consequently, this observable is calibrated using simulated events, and translated to a top-quark mass estimation using relativistic kinematics. The measurement yields a value of mt = 172 . 29 +/- 1 . 17 (stat .) +/- 2 . 66 (syst .) GeV .

  12. Energy Spectrum and Composition of Ultra High Energy Cosmic Ray Showers Using Hybrid Analysis from Telescope Array

    NASA Astrophysics Data System (ADS)

    Allen, Monica; Abu-Zayyad, Tareq; Stokes, Benjamin T.

    2012-10-01

    The Telescope Array studies ultra high energy cosmic rays using a hybrid detector. Fluorescence telescopes measure the longitudinal development of the extensive air shower generated by a primary cosmic ray particle, while scintillator detectors measure the lateral distribution of secondary particles that hit the ground. The Middle Drum (MD) fluorescence telescope consists of 14 refurbished telescopes from the High Resolution Fly's Eye experiment (HiRes), providing a direct link back to the HiRes experiment and data. Using the scintillator detector data in conjunction with the MD data improves the geometrical reconstruction of the showers significantly, and hence, provides a more accurate reconstruction of the energy of the primary particle. The Middle Drum hybrid spectrum will be presented. In addition, a MD hybrid composition study was also performed, and results will be shown.

  13. Spectrum splitting using multi-layer dielectric meta-surfaces for efficient solar energy harvesting

    NASA Astrophysics Data System (ADS)

    Yao, Yuhan; Liu, He; Wu, Wei

    2014-06-01

    We designed a high-efficiency dispersive mirror based on multi-layer dielectric meta-surfaces. By replacing the secondary mirror of a dome solar concentrator with this dispersive mirror, the solar concentrator can be converted into a spectrum-splitting photovoltaic system with higher energy harvesting efficiency and potentially lower cost. The meta-surfaces are consisted of high-index contrast gratings (HCG). The structures and parameters of the dispersive mirror (i.e. stacked HCG) are optimized based on finite-difference time-domain and rigorous coupled-wave analysis method. Our numerical study shows that the dispersive mirror can direct light with different wavelengths into different angles in the entire solar spectrum, maintaining very low energy loss. Our approach will not only improve the energy harvesting efficiency, but also lower the cost by using single junction cells instead of multi-layer tandem solar cells. Moreover, this approach has the minimal disruption to the existing solar concentrator infrastructures.

  14. Bounds on the solar antineutrino total flux and energy spectrum from the SK experiment

    NASA Astrophysics Data System (ADS)

    Torrente-Lujan, E.

    2000-11-01

    A search for inverse beta decay electron antineutrinos has been carried out using the 825 days sample of solar data obtained at SK. The absence of a significant signal, that is, contributions to the total SK background and their angular variations has set upper bounds on (a) the absolute flux of solar antineutrinos originated from 8B neutrinos Φν¯(8B)<=1.8×105 cm-2s-1 which is equivalent to an averaged conversion probability bound of /P<3.5% (SSM-BP98 model) and (b) their differential energy spectrum, the conversion probability is smaller than 8% for all Ee,vis>6.5 MeV going down the 5% level above Ee,vis~10 MeV. It is shown that an antineutrino flux would have the net effect of enhancing the SK signal at hep neutrino energies. The magnitude of this enhancement would highly depend on the, otherwise rather uncertain at this moment, steepness of the solar neutrino spectrum at these energies.

  15. The H(3) (+) rovibrational spectrum revisited with a global electronic potential energy surface.

    PubMed

    Velilla, Luis; Lepetit, Bruno; Aguado, Alfredo; Beswick, J Alberto; Paniagua, Miguel

    2008-08-28

    In this paper, we have computed the rovibrational spectrum of the H(3) (+) molecule using a new global potential energy surface, invariant under all permutations of the nuclei, that includes the long range electrostatic interactions analytically. The energy levels are obtained by a variational calculation using hyperspherical coordinates. From the comparison with available experimental results for low lying levels, we conclude that our accuracy is of the order of 0.1 cm(-1) for states localized in the vicinity of equilateral triangular configurations of the nuclei, and changes to the order of 1 cm(-1) when the system is distorted away from equilateral configurations. Full rovibrational spectra up to the H(+)+H(2) dissociation energy limit have been computed. The statistical properties of this spectrum (nearest neighbor distribution and spectral rigidity) show the quantum signature of classical chaos and are consistent with random matrix theory. On the other hand, the correlation function, even when convoluted with a smoothing function, exhibits oscillations which are not described by random matrix theory. We discuss a possible similarity between these oscillations and the ones observed experimentally.

  16. The energy spectrum of X-rays from rocket-triggered lightning

    NASA Astrophysics Data System (ADS)

    Arabshahi, S.; Dwyer, J. R.; Cramer, E. S.; Grove, J. E.; Gwon, C.; Hill, J. D.; Jordan, D. M.; Lucia, R. J.; Vodopiyanov, I. B.; Uman, M. A.; Rassoul, H. K.

    2015-10-01

    Although the production of X-rays from natural and rocket-triggered lightning leaders have been studied in detail over the last 10 years, the energy spectrum of the X-rays has never been well measured because the X-rays are emitted in very short but intense bursts that result in pulse pileup in the detectors. The energy spectrum is important because it provides information about the source mechanism for producing the energetic runaway electrons and about the electric fields that they traverse. We have recently developed and operated the first spectrometer for the energetic radiation from lightning. The instrument is part of the Atmospheric Radiation Imagery and Spectroscopy (ARIS) project and will be referred to as ARIS-S (ARIS Spectrometer). It consists of seven 3'' NaI(Tl)/photomultiplier tube scintillation detectors with different thicknesses of attenuators, ranging from no attenuator to more than 1'' of lead placed over the detector (all the detectors are in a 1/8'' thick aluminum box). Using X-ray pulses preceding 48 return strokes in 8 rocket-triggered lightnings, we found that the spectrum of X-rays from leaders is too soft to be consistent with Relativistic Runaway Electron Avalanche. It has a power law dependence on the energies of the photons, and the power index, λ, is between 2.5 and 3.5. We present the details of the design of the instrument and the results of the analysis of the lightning data acquired during the summer of 2012.

  17. Effect of photon energy spectrum on dosimetric parameters of brachytherapy sources

    PubMed Central

    Ghorbani, Mahdi; Davenport, David

    2016-01-01

    Abstract Aim The aim of this study is to quantify the influence of the photon energy spectrum of brachytherapy sources on task group No. 43 (TG-43) dosimetric parameters. Background Different photon spectra are used for a specific radionuclide in Monte Carlo simulations of brachytherapy sources. Materials and methods MCNPX code was used to simulate 125I, 103Pd, 169Yb, and 192Ir brachytherapy sources. Air kerma strength per activity, dose rate constant, radial dose function, and two dimensional (2D) anisotropy functions were calculated and isodose curves were plotted for three different photon energy spectra. The references for photon energy spectra were: published papers, Lawrence Berkeley National Laboratory (LBNL), and National Nuclear Data Center (NNDC). The data calculated by these photon energy spectra were compared. Results Dose rate constant values showed a maximum difference of 24.07% for 103Pd source with different photon energy spectra. Radial dose function values based on different spectra were relatively the same. 2D anisotropy function values showed minor differences in most of distances and angles. There was not any detectable difference between the isodose contours. Conclusions Dosimetric parameters obtained with different photon spectra were relatively the same, however it is suggested that more accurate and updated photon energy spectra be used in Monte Carlo simulations. This would allow for calculation of reliable dosimetric data for source modeling and calculation in brachytherapy treatment planning systems. PMID:27247558

  18. Fractal Energy Spectrum of a Polariton Gas in a Fibonacci Quasiperiodic Potential

    NASA Astrophysics Data System (ADS)

    Tanese, D.; Gurevich, E.; Baboux, F.; Jacqmin, T.; Lemaètre, A.; Galopin, E.; Sagnes, I.; Amo, A.; Bloch, J.; Akkermans, E.

    2014-04-01

    We report on the study of a polariton gas confined in a quasiperiodic one-dimensional cavity, described by a Fibonacci sequence. Imaging the polariton modes both in real and reciprocal space, we observe features characteristic of their fractal energy spectrum such as the opening of minigaps obeying the gap labeling theorem and log-periodic oscillations of the integrated density of states. These observations are accurately reproduced solving an effective 1D Schrödinger equation, illustrating the potential of cavity polaritons as a quantum simulator in complex topological geometries.

  19. Fractal energy spectrum of a polariton gas in a Fibonacci quasiperiodic potential.

    PubMed

    Tanese, D; Gurevich, E; Baboux, F; Jacqmin, T; Lemaître, A; Galopin, E; Sagnes, I; Amo, A; Bloch, J; Akkermans, E

    2014-04-11

    We report on the study of a polariton gas confined in a quasiperiodic one-dimensional cavity, described by a Fibonacci sequence. Imaging the polariton modes both in real and reciprocal space, we observe features characteristic of their fractal energy spectrum such as the opening of minigaps obeying the gap labeling theorem and log-periodic oscillations of the integrated density of states. These observations are accurately reproduced solving an effective 1D Schrödinger equation, illustrating the potential of cavity polaritons as a quantum simulator in complex topological geometries.

  20. COMPREHENSIVE OBSERVATIONS OF THE ULTRAVIOLET SPECTRUM AND IMPROVED ENERGY LEVELS FOR SINGLY IONIZED CHROMIUM (Cr II)

    SciTech Connect

    Sansonetti, Craig J.; Nave, Gillian; Reader, Joseph; Kerber, Florian

    2012-10-15

    We report new observations of the spectrum of singly ionized chromium (Cr II) in the region 1142-3954 A. The spectra were recorded with the National Institute of Standards and Technology 10.7 m normal-incidence vacuum spectrograph and FT700 vacuum ultraviolet Fourier transform spectrometer. More than 3600 lines are classified as transitions among 283 even and 368 odd levels. The new spectral data are used to re-optimize the energy levels, reducing their uncertainties by a typical factor of 20.

  1. Comprehensive Observations of the Ultraviolet Spectrum and Improved Energy Levels for Singly Ionized Chromium (Cr II)

    NASA Astrophysics Data System (ADS)

    Sansonetti, Craig J.; Nave, Gillian; Reader, Joseph; Kerber, Florian

    2012-10-01

    We report new observations of the spectrum of singly ionized chromium (Cr II) in the region 1142-3954 Å. The spectra were recorded with the National Institute of Standards and Technology 10.7 m normal-incidence vacuum spectrograph and FT700 vacuum ultraviolet Fourier transform spectrometer. More than 3600 lines are classified as transitions among 283 even and 368 odd levels. The new spectral data are used to re-optimize the energy levels, reducing their uncertainties by a typical factor of 20.

  2. Quantum control of isomerization by robust navigation in the energy spectrum

    NASA Astrophysics Data System (ADS)

    Murgida, G. E.; Arranz, F. J.; Borondo, F.

    2015-12-01

    In this paper, we present a detailed study on the application of the quantum control technique of navigation in the energy spectrum to chemical isomerization processes, namely, CN-Li⇆ Li-CN. This technique is based on the controlled time variation of a Hamiltonian parameter, an external uniform electric field in our case. The main result of our work establishes that the navigation involved in the method is robust, in the sense that quite sizable deviations from a pre-established control parameter time profile can be introduced and still get good final results. This is specially relevant thinking of a experimental implementation of the method.

  3. Quantum control of isomerization by robust navigation in the energy spectrum

    SciTech Connect

    Murgida, G. E.; Arranz, F. J.; Borondo, F.

    2015-12-07

    In this paper, we present a detailed study on the application of the quantum control technique of navigation in the energy spectrum to chemical isomerization processes, namely, CN–Li⇆ Li–CN. This technique is based on the controlled time variation of a Hamiltonian parameter, an external uniform electric field in our case. The main result of our work establishes that the navigation involved in the method is robust, in the sense that quite sizable deviations from a pre-established control parameter time profile can be introduced and still get good final results. This is specially relevant thinking of a experimental implementation of the method.

  4. Comparative characteristics of electron energy spectrum in PIG and arc type discharge plasmas

    NASA Technical Reports Server (NTRS)

    Romanyuk, L. I.; Suavilnyy, N. Y.

    1978-01-01

    The electron distribution functions relative to the velocity component directed along the magnetic field are compared for PIG and arc type discharges. The identity of these functions for the plasma region pierced by the primary electron beam and their difference in the peripheral part of the discharge are shown. It is concluded that the electron distribution function in the PIG type discharge is formed during one transit of the primary electron through the discharge gap. The mechanisms of electron energy spectrum formation in both the axis region and the peripheral region of the discharge are discussed.

  5. Very high energy gamma-rays from flat spectrum radio quasars

    NASA Astrophysics Data System (ADS)

    Lindfors, Elina

    2015-03-01

    The detection of Flat Spectrum Radio Quasars (FSRQs) in the Very High Energy (VHE, E>100 GeV) range is challenging, mainly because of their steep soft spectra and distance. Nevertheless four FSRQs are now known to be VHE emitters. The detection of the VHE γ-rays has challenged the emission models of these sources. The sources are also found to exhibit very different behavior. I will give an overview of what is known about the VHE emission of these sources and about the multiwavelength signatures that are connected to the VHE gamma-ray emission.

  6. Spectrum and energy levels of quadruply-ionized molybdenum (Mo V)

    NASA Astrophysics Data System (ADS)

    Reader, Joseph; Tauheed, Ahmad

    2015-07-01

    The spectrum of quadruply-ionized molybdenum Mo V was observed from 200 to 4700 Å with sliding spark discharges on 10.7 m normal- and grazing-incidence spectrographs. The existing analyses of this spectrum (Tauheed et al 1985 Phys. Scr. 31 369; Cabeza et al 1986 Phys. Scr. 34 223) were extended to include the 5s2, 5p2, 5s5d, 5s6s, 4d5f, and 4d5g configurations as well as the missing 3H6 level of 4d4f and about 75 levels of the core-excited configuration 4p54d3. The values of the 4d5d 1S0, 5s5p 1P1, and 4d6p 3P0 levels were revised. There are now about 900 lines classified as transitions between 66 even parity and 191 odd parity energy levels. Of these, about 600 lines and 130 levels are new. From the optimized energy level values, Ritz-type wavelengths were determined for about 380 lines, with uncertainties varying from 0.0003 to 0.002 Å. The observed configurations were theoretically interpreted by means of Hartree-Fock calculations and least-squares fits of the energy parameters to the observed levels. The fitted parameters were used to calculate oscillator strengths for all classified lines. A few unclassified lines and undesignated levels are also given. An improved value for the ionization energy was obtained by combining the observed energy of the 4d5g configuration with an ab initio calculation of its term value. The adopted value is 438 900 ± 150 cm-1 (54.417 ± 0.019 eV).

  7. A study of radio frequency spectrum emitted by high energy air showers with LOFAR

    NASA Astrophysics Data System (ADS)

    Rossetto, Laura; Bonardi, Antonio; Buitink, Stijn; Corstanje, Arthur; Enriquez, J. Emilio; Falcke, Heino; Hörandel, Jörg R.; Mitra, Pragati; Mulrey, Katie; Nelles, Anna; Rachen, Jörg P.; Schellart, Pim; Scholten, Olaf; Thoudam, Satyendra; Trinh, Gia; ter Veen, Sander; Winchen, Tobias

    2017-03-01

    The high number density of radio antennas at the LOFAR core in Northern Netherlands allows to detect radio signals emitted by cosmic ray induced air showers, and to characterize the geometry of the observed cascade in a detailed way. We present here a study of the radio frequency spectrum in the 30 - 80 MHz regime, and its correlation with some geometrical parameters of the extensive air shower. An important goal of this study is to find a correlation between the frequency spectrum and the primary particle type. Preliminary results on how the frequency spectrum changes as function of distance to the shower axis, and as function of primary particles mass composition are shown. The final aim of this study is to find a method to infer information of primary cosmic rays in an independent way from the well-established fluorescence and surface detector techniques, in view of affirming the radio detection technique as reliable method for the study of high energy cosmic rays.

  8. Dual energy CT via fast kVp switching spectrum estimation

    NASA Astrophysics Data System (ADS)

    Xu, Dan; Langan, David A.; Wu, Xiaoye; Pack, Jed D.; Benson, Thomas M.; Tkaczky, J. Eric; Schmitz, Andrea M.

    2009-02-01

    Recently there has been significant interest in dual energy CT imaging with several acquisition methods being actively pursued. Here we investigate fast kVp switching where the kVp alternates between low and high kVp every view. Fast kVp switching enables fine temporal registration, helical and axial acquisitions, and full field of view. It also presents several processing challenges. The rise and fall of the kVp, which occurs during the view integration period, is not instantaneous and complicates the measurement of the effective spectrum for low and high kVp views. Further, if the detector digital acquisition system (DAS) and generator clocks are not fully synchronous, jitter is introduced in the kVp waveform relative to the view period. In this paper we develop a method for estimation of the resulting spectrum for low and high kVp views. The method utilizes static kVp acquisitions of air with a small bowtie filter as a basis set. A fast kVp acquisition of air with a small bowtie filter is performed and the effective kVp is estimated as a linear combination of the basis vectors. The effectiveness of this method is demonstrated through the reconstruction of a water phantom acquired with a fast kVp acquisition. The impact of jitter due to the generator and detector DAS clocks is explored via simulation. The error is measured relative to spectrum variation and material decomposition accuracy.

  9. Excitation energy-dependent nature of Raman scattering spectrum in GaInNAs/GaAs quantum well structures.

    PubMed

    Erol, Ayse; Akalin, Elif; Sarcan, Fahrettin; Donmez, Omer; Akyuz, Sevim; Arikan, Cetin M; Puustinen, Janne; Guina, Mircea

    2012-11-28

    The excitation energy-dependent nature of Raman scattering spectrum, vibration, electronic or both, has been studied using different excitation sources on as-grown and annealed n- and p-type modulation-doped Ga1 - xInxNyAs1 - y/GaAs quantum well structures. The samples were grown by molecular beam technique with different N concentrations (y = 0%, 0.9%, 1.2%, 1.7%) at the same In concentration of 32%. Micro-Raman measurements have been carried out using 532 and 758 nm lines of diode lasers, and the 1064 nm line of the Nd-YAG laser has been used for Fourier transform-Raman scattering measurements. Raman scattering measurements with different excitation sources have revealed that the excitation energy is the decisive mechanism on the nature of the Raman scattering spectrum. When the excitation energy is close to the electronic band gap energy of any constituent semiconductor materials in the sample, electronic transition dominates the spectrum, leading to a very broad peak. In the condition that the excitation energy is much higher than the band gap energy, only vibrational modes contribute to the Raman scattering spectrum of the samples. Line shapes of the Raman scattering spectrum with the 785 and 1064 nm lines of lasers have been observed to be very broad peaks, whose absolute peak energy values are in good agreement with the ones obtained from photoluminescence measurements. On the other hand, Raman scattering spectrum with the 532 nm line has exhibited only vibrational modes. As a complementary tool of Raman scattering measurements with the excitation source of 532 nm, which shows weak vibrational transitions, attenuated total reflectance infrared spectroscopy has been also carried out. The results exhibited that the nature of the Raman scattering spectrum is strongly excitation energy-dependent, and with suitable excitation energy, electronic and/or vibrational transitions can be investigated.

  10. Hydromorphological adjustments and re-adjustments of low energy rivers in a sub-urban catchment following historical engineering and recent urbanization

    NASA Astrophysics Data System (ADS)

    Jugie, Marion; Gob, Frédéric; Slawson, Deborah; Le-Coeur, Charles

    2014-05-01

    The EU Water Framework Directive (WFD, October 2000) mandated that the Member States of the European Union achieve the general objective of protection of aquatic ecology by 2015. European rivers and streams have to attain "good ecological status" through the preservation and restoration of aquatic environments. Member will have to ensure environmental continuity through "the adequate distribution of fish species and transport of sediments". In France, more than 61,000 transverse structures - mill dams, weirs, diversion gates - have been identified on rivers as being obstacles to ecological and sedimentary continuity. Because of their historical occupation by societies, rivers flowing in the Paris area have long been anthropized and artificialized. River courses, channel shape, sediment transport and hydrological regime modifications have tremendously transformed the hydrosystems surrounding the city of Paris. The Merantaise's catchment is one of this low energy river watershed, near Paris, that have been modified by historical engineering, especially during medieval-modern times and by the building of the Versailles Castle (XVIIth century). The hydraulic infrastructures are still there and impact the hydromorphogical conditions of the river (incision, lateral erosion, …). In addition to these ancient pressures a rapid and massive urbanization of the suburban areas has applied a new type of constraint to the hydrosystems in recent decades. This undermines the balance that was established following ancient engineering and disturbs the current functioning of the valley. These new types of land occupation have significantly altered the ecological circumstances and transformed the hydrological responses of rivers. In this study, we therefore seek to understand these processes of successive adjustments (ancient and recent) of a small river from the urban margins of the Orge watershed (to the south of Paris). We use a multi-scalar spatial and temporal approach to

  11. Multimode stretched spiral vortex and nonequilibrium energy spectrum in homogeneous shear flow turbulence

    NASA Astrophysics Data System (ADS)

    Horiuti, Kiyosi; Ozawa, Tetsuya

    2011-03-01

    The stretched spiral vortex [T. S. Lundgren, "Strained spiral vortex model for turbulent structures," Phys. Fluids 25, 2193 (1982)] is identified in turbulence in homogeneous shear flow and the spectral properties of this flow are studied using direct-numerical simulation data. The effects of mean shear on the genesis, growth, and annihilation processes of the spiral vortex are elucidated, and the role of the spiral vortex in the generation of turbulence is shown. As in homogeneous isotropic turbulence [K. Horiuti and T. Fujisawa, "The multi mode stretched spiral vortex in homogeneous isotropic turbulence," J. Fluid Mech. 595, 341 (2008)], multimodes of the spiral vortex are extracted. Two symmetric modes of configurations with regard to the vorticity alignment along the vortex tube in the core region and dual vortex sheets spiraling around the tube are often educed. One of the two symmetric modes is created by a conventional rolling-up of a single spanwise shear layer. Another one is created by the convergence of the recirculating flow or streamwise roll [F. Waleffe, "Homotopy of exact coherent structures in plane shear flows," Phys. Fluids 15, 1517 (2003)] caused by the upward and downward motions associated with the streaks. The vortex tube is formed by axial straining and lowering of pressure in the recirculating region. The spanwise shear layers are entrained by the tube and they form spiral turns. The latter symmetric mode tends to be transformed into the former mode with lapse of time due to the action of the pressure Hessian term. The power law in the inertial subrange energy spectrum is studied. The base steady spectrum fits the equilibrium Kolmogorov -5/3 spectrum, to which a nonequilibrium component induced by the fluctuation of the dissipation rate ɛ is added. This component is extracted using the conditional sampling on ɛ, and it is shown that it fits the -7/3 power in accordance with the statistical theory. The correlation between these spectra and

  12. Neutron dosimetry, moderated energy spectrum, and neutron capture therapy for californium-252 medical sources

    NASA Astrophysics Data System (ADS)

    Rivard, Mark Joseph

    Examination of neutron dosimetry for 252Cf has been conducted using calculative and experimental means. Monte Carlo N-Particle (MCNP) transport code was used in a distributed computing environment as a parallel virtual machine (PVM) to determine the absorbed neutron dose and neutron energy spectrum from 252Cf in a variety of clinically relevant materials. Herein, a Maxwellian spectrum was used to model the 252Cf neutron emissions within these materials. 252Cf mixed-field dosimetry of Applicator Tube (AT) type sources was measured using 1.0 and 0.05 cm3 tissue-equivalent ion chambers and a miniature GM counter. A dosimetry protocol was formulated similar that of ICRU 45. The 252Cf AT neutron dosimetry was determined in the cylindrical coordinate system formalism recommended by the AAPM Task Group 43. These results demonstrated the overwhelming dependence of dosimetry on the source geometry factor as there was no significant neutron attenuation within the source or encapsulation. Gold foils and TLDs were used to measure the thermal flux in the vicinity of 252Cf AT sources to compare with the results calculated using MCNP. As the fast neutron energy spectrum did not markedly changed at increasing distances from the AT source, neutron dosimetry results obtained with paired ion chambers using fixed sensitivity factors agreed well with MCNP results and those in the literature. Calculations of moderated 252Cf neutron energy spectrum with various loadings of 10B and 157Gd were performed, in addition to analysis of neutron capture therapy dosimetry with these isotopes. Radiological concerns such as personnel exposure and shielding of 252Cf emissions were examined. Feasibility of a high specific-activity 252Cf HDR source was investigated through radiochemical and metallurgical studies using stand-ins such as Tb, Gd and 249Cf. Issues such as capsule burst strength due to helium production for a variety of proposed HDR sources were addressed. A recommended 252Cf source

  13. Exclusive Measurements of the b to s gamma Transition Rate and Photon Energy Spectrum

    SciTech Connect

    Lees, J.P.; Poireau, V.; Tisserand, V.; Garra Tico, J.; Grauges, E.; Palano, A.; Eigen, G.; Stugu, B.; Brown, David Nathan; Kerth, L.T.; Kolomensky, Yu.G.; Lynch, G.; Koch, H.; Schroeder, T.; Asgeirsson, D.J.; Hearty, C.; Mattison, T.S.; McKenna, J.A.; Khan, A.; Blinov, V.E.; Buzykaev, A.R.; /more authors..

    2012-08-30

    We use 429 fb{sup -1} of e{sup +}e{sup -} collision data collected at the {Upsilon}(4S) resonance with the BABAR detector to measure the radiative transition rate of b {yields} s{gamma} with a sum of 38 exclusive final states. The inclusive branching fraction with a minimum photon energy of 1.9 GeV is found to be {Beta}({bar B} {yields} Xs{gamma}) = (3.29 {+-} 0.19 {+-} 0.48) x 10{sup -4} where the first uncertainty is statistical and the second is systematic. We also measure the first and second moments of the photon energy spectrum and extract the best fit values for the heavy-quark parameters, m{sub b} and {mu}{sub {pi}}{sup 2}, in the kinetic and shape function models.

  14. The spectrum of galactic electrons with energies between 10 and 900 GeV

    NASA Technical Reports Server (NTRS)

    Mueller, D.; Meyer, P.

    1973-01-01

    A cosmic-ray electron detector has been exposed during 1970 in three high-altitude balloon flights from Palestine, Texas. The data analysis is based on results from accelerator calibrations with electrons and pions at SLAC. Discrimination against a contamination of the electron data due to interacting protons has been achieved by statistical methods. The resulting differential energy spectrum of cosmic-ray electrons can be well described by a single power law with spectral index 2.66 plus or minus 0.1 up to energies around 250 GeV. Within the experimental uncertainty, no change in this spectral slope up to almost 1000 GeV can be detected. Some implications of these results are discussed.

  15. Analysis of the Zeeman effect on the energy spectrum in graphenes

    SciTech Connect

    Feng, Sze-Shiang; Mochena, Mogus

    2011-08-15

    An analysis of the Zeeman effect with a strong external magnetic field on the energy spectrum in graphene is presented. In general, the Hamiltonian of graphene in applied electric and magnetic fields is not of SO(1, 2) invariance even in the nearest-neighbor approximation because of the Zeeman coupling. But an approximate SO(1, 2) invariance can be obtained when the applied magnetic field is very strong. This approximate invariance can be used to relate the energy structure of graphene in the presence of both electric and magnetic fields to that when there is only magnetic field. Therefore, it can help explain the recently found quantum Hall conductance (4q{sup 2}/h)L for L = 0.1.

  16. The neutron dose and energy spectrum outside a 20-MV accelerator treatment room.

    PubMed

    Muller-Runkel, R; Ovadia, J; Culbert, H; Cooke, R H; Dolecek, E H

    1986-01-01

    A maze design is discussed for a Therac 20 linear accelerator (manufactured by Atomic Energy of Canada, Ltd.) which reduces the flux of neutrons at the door to permissible levels in controlled areas. The L-shaped design allows for a relatively light door at the end of the maze, consisting of 5.08-cm (2-in.) borated polyethylene and 2-mm lead. A comparison is made between the neutron dose equivalent (DE) calculated by various methods and the DE measured with a variety of portable neutron survey meters. In addition, the neutron energy spectrum outside the maze at 1 m from the door, measured with a polyethylene multisphere LiI system, is reported.

  17. Neutron dose and energy spectrum outside a 20-MV accelerator treatment room

    SciTech Connect

    Muller-Runkel, R.; Ovadia, J.; Culbert, H.; Cooke, R.H.; Dolecek, E.H.

    1986-09-01

    A maze design is discussed for a Therac 20 linear accelerator (manufactured by Atomic Energy of Canada, Ltd.) which reduces the flux of neutrons at the door to permissible levels in controlled areas. The L-shaped design allows for a relatively light door at the end of the maze, consisting of 5.08-cm (2-in.) borated polyethylene and 2-mm lead. A comparison is made between the neutron dose equivalent (DE) calculated by various methods and the DE measured with a variety of portable neutron survey meters. In addition, the neutron energy spectrum outside the maze at 1 m from the door, measured with a polyethylene multisphere LiI system, is reported.

  18. Vertical transition energies vs. absorption maxima: illustration with the UV absorption spectrum of ethylene.

    PubMed

    Lasorne, Benjamin; Jornet-Somoza, Joaquim; Meyer, Hans-Dieter; Lauvergnat, David; Robb, Michael A; Gatti, Fabien

    2014-02-05

    We revisit the validity of making a direct comparison between measured absorption maxima and computed vertical transition energies within 0.1 eV to calibrate an excited-state level of theory. This is illustrated on the UV absorption spectrum of ethylene for which the usual experimental values of 7.66 eV (V←N) and 7.11 eV (R(3s)←N) cannot be compared directly to the results of electronic structure calculations for two very different reasons. After validation of our level of theory against experimental data, a new experimental reference of 7.28 eV is suggested for benchmarking the Rydberg state, and the often-cited average transition energy (7.80 eV) is confirmed as a safer estimate for the valence state.

  19. Energy spectrum and effective mass of carriers in the InSe/GaSe superlattice

    NASA Astrophysics Data System (ADS)

    Gashimzade, F. M.; Mustafaev, N. B.

    1995-03-01

    Within an effective mass approximation the energy spectrum and mass of carriers in the InSe/GaSe superlattice have been calculated. The superlattice belongs to type II: electrons are primarily confined to the InSe layers whereas the holes are mosfly confined to the GaSe layers. The characteristic feature of electronic structure of the superlattice is the existence of minibands of light carriers at the θ point of the Brillouin zone and minibands of heavy carriers at the M point. The dependence of the miniband structure on thickness of layers has been computed. It is shown that the minibands of light and heavy carriers compete with one another in energy. A general conclusion is made concerning the influence of the competition between the minibands on optic and kinetic properties of the superlattice.

  20. Possible Interpretations of the High Energy Cosmic Ray Electron Spectrum Measured with the Fermi Space Telescope

    SciTech Connect

    Grasso, D.; Profumo, S.; Strong, A.W.; Baldini, L.; Bellazzini, R.; Bloom, E.D.; Bregeon, J.; Di Bernardo, G.; Gaggero, D.; Giglietto, N.; Kamae, T.; Latronico, L.; Longo, F.; Mazziotta, M.N.; Moiseev, A.A.; Morselli, A.; Ormes, J.F.; Pesce-Rollins, M.; Pohl, M.; Razzano, M.; Sgro, C.; /INFN, Pisa /INFN, Pisa /NASA, Ames

    2012-04-25

    The Fermi Large Area Telescope has provided the measurement of the high energy (20 GeV to 1 TeV) cosmic ray electrons and positrons spectrum with unprecedented accuracy. This measurement represents a unique probe for studying the origin and diffusive propagation of cosmic rays as well as for looking for possible evidences of Dark Matter. In this contribution we focus mainly on astrophysical sources of cosmic ray electrons and positrons which include the standard primary and secondary diffuse galactic contribution, as well as nearby point-sources which are expected to contribute more significantly to higher energies. In this framework, we discuss possible interpretations of Fermi results in relation with other recent experimental data on energetic electrons and positrons (specifically the most recent ones reported by PAMELA, ATIC, PPB-BETS and H.E.S.S.).

  1. Evaluation of the beta energy spectrum from a distributed uranium mill tailings source

    SciTech Connect

    Reif, R.H.; Martz, D.E.; Carlson, D.S.; Turner, J.B. )

    1993-10-01

    The beta energy spectra from uranium mill tailings, 90Sr with different absorber thicknesses, and a uranium metal slab were measured and compared to select an appropriate beta source for calibrating a personal dosimeter to measure shallow dose equivalent when exposed to uranium mill tailings. The measured beta energy spectrum from the 90Sr source, with a 111 mg cm-2 cover thickness, was selected as a possible calibration source for a personnel dosimeter. The dose equivalent rate to the skin at 1 cm from a distributed tailings source of infinite thickness, with a 226Ra activity of 56 Bq g-1 (1.5 x 10(3) pCi g-1), was measured to be 0.024 mSv h-1 (2.4 mrem h-1).

  2. Evaluation of the beta energy spectrum from a distributed uranium mill tailings source.

    PubMed

    Reif, R H; Martz, D E; Carlson, D S; Turner, J B

    1993-10-01

    The beta energy spectra from uranium mill tailings, 90Sr with different absorber thicknesses, and a uranium metal slab were measured and compared to select an appropriate beta source for calibrating a personal dosimeter to measure shallow dose equivalent when exposed to uranium mill tailings. The measured beta energy spectrum from the 90Sr source, with a 111 mg cm-2 cover thickness, was selected as a possible calibration source for a personnel dosimeter. The dose equivalent rate to the skin at 1 cm from a distributed tailings source of infinite thickness, with a 226Ra activity of 56 Bq g-1 (1.5 x 10(3) pCi g-1), was measured to be 0.024 mSv h-1 (2.4 mrem h-1).

  3. Ion energy spectrum of expanding laser-plasma with limited mass

    SciTech Connect

    Murakami, M.; Kang, Y.-G.; Nishihara, K.; Fujioka, S.; Nishimura, H.

    2005-06-15

    A simple analytical model is presented for hydrodynamic expansion of laser-produced plasma with a limited mass, which expands quasi-isothermally during laser irradiation and quasiadiabatically after turning off the laser. During the isothermal expansion, the masses undergo entire disintegration under a relatively long laser pulse, while the ions are being kept accelerated. This physical picture significantly contrasts with that described by the orthodox self-similar solution for a semi-infinite planar rarefaction wave. The two successive expansions, i.e., isothermal expansion followed by adiabatic expansion, are described, respectively, by different self-similar solutions, which are found to be connected smoothly with each other in time and space. The ion energy spectrum obtained by the model reproduces well experimental results obtained under different geometrical conditions. The maximum ion kinetic energy is also estimated in terms of the laser and target parameters.

  4. Exclusive measurements of b→sγ transition rate and photon energy spectrum

    NASA Astrophysics Data System (ADS)

    Lees, J. P.; Poireau, V.; Tisserand, V.; Garra Tico, J.; Grauges, E.; Palano, A.; Eigen, G.; Stugu, B.; Brown, D. N.; Kerth, L. T.; Kolomensky, Yu. G.; Lynch, G.; Koch, H.; Schroeder, T.; Asgeirsson, D. J.; Hearty, C.; Mattison, T. S.; McKenna, J. A.; Khan, A.; Blinov, V. E.; Buzykaev, A. R.; Druzhinin, V. P.; Golubev, V. B.; Kravchenko, E. A.; Onuchin, A. P.; Serednyakov, S. I.; Skovpen, Yu. I.; Solodov, E. P.; Todyshev, K. Yu.; Yushkov, A. N.; Bondioli, M.; Kirkby, D.; Lankford, A. J.; Mandelkern, M.; Atmacan, H.; Gary, J. W.; Liu, F.; Long, O.; Vitug, G. M.; Campagnari, C.; Hong, T. M.; Kovalskyi, D.; Richman, J. D.; West, C. A.; Eisner, A. M.; Kroseberg, J.; Lockman, W. S.; Martinez, A. J.; Schumm, B. A.; Seiden, A.; Chao, D. S.; Cheng, C. H.; Doll, D. A.; Echenard, B.; Flood, K. T.; Hitlin, D. G.; Ongmongkolkul, P.; Porter, F. C.; Rakitin, A. Y.; Andreassen, R.; Huard, Z.; Meadows, B. T.; Sokoloff, M. D.; Sun, L.; Bloom, P. C.; Ford, W. T.; Gaz, A.; Nauenberg, U.; Smith, J. G.; Wagner, S. R.; Ayad, R.; Toki, W. H.; Spaan, B.; Schubert, K. R.; Schwierz, R.; Bernard, D.; Verderi, M.; Clark, P. J.; Playfer, S.; Bettoni, D.; Bozzi, C.; Calabrese, R.; Cibinetto, G.; Fioravanti, E.; Garzia, I.; Luppi, E.; Munerato, M.; Negrini, M.; Piemontese, L.; Santoro, V.; Baldini-Ferroli, R.; Calcaterra, A.; de Sangro, R.; Finocchiaro, G.; Patteri, P.; Peruzzi, I. M.; Piccolo, M.; Rama, M.; Zallo, A.; Contri, R.; Guido, E.; Lo Vetere, M.; Monge, M. R.; Passaggio, S.; Patrignani, C.; Robutti, E.; Bhuyan, B.; Prasad, V.; Lee, C. L.; Morii, M.; Edwards, A. J.; Adametz, A.; Uwer, U.; Lacker, H. M.; Lueck, T.; Dauncey, P. D.; Behera, P. K.; Mallik, U.; Chen, C.; Cochran, J.; Meyer, W. T.; Prell, S.; Rubin, A. E.; Gritsan, A. V.; Guo, Z. J.; Arnaud, N.; Davier, M.; Derkach, D.; Grosdidier, G.; Le Diberder, F.; Lutz, A. M.; Malaescu, B.; Roudeau, P.; Schune, M. H.; Stocchi, A.; Wormser, G.; Lange, D. J.; Wright, D. M.; Chavez, C. A.; Coleman, J. P.; Fry, J. R.; Gabathuler, E.; Hutchcroft, D. E.; Payne, D. J.; Touramanis, C.; Bevan, A. J.; Di Lodovico, F.; Sacco, R.; Sigamani, M.; Cowan, G.; Brown, D. N.; Davis, C. L.; Denig, A. G.; Fritsch, M.; Gradl, W.; Griessinger, K.; Hafner, A.; Prencipe, E.; Bailey, D.; Barlow, R. J.; Jackson, G.; Lafferty, G. D.; Behn, E.; Cenci, R.; Hamilton, B.; Jawahery, A.; Roberts, D. A.; Dallapiccola, C.; Cowan, R.; Dujmic, D.; Sciolla, G.; Cheaib, R.; Lindemann, D.; Patel, P. M.; Robertson, S. H.; Biassoni, P.; Neri, N.; Palombo, F.; Stracka, S.; Cremaldi, L.; Godang, R.; Kroeger, R.; Sonnek, P.; Summers, D. J.; Nguyen, X.; Simard, M.; Taras, P.; De Nardo, G.; Monorchio, D.; Onorato, G.; Sciacca, C.; Martinelli, M.; Raven, G.; Jessop, C. P.; LoSecco, J. M.; Wang, W. F.; Honscheid, K.; Kass, R.; Brau, J.; Frey, R.; Sinev, N. B.; Strom, D.; Torrence, E.; Feltresi, E.; Gagliardi, N.; Margoni, M.; Morandin, M.; Posocco, M.; Rotondo, M.; Simi, G.; Simonetto, F.; Stroili, R.; Akar, S.; Ben-Haim, E.; Bomben, M.; Bonneaud, G. R.; Briand, H.; Calderini, G.; Chauveau, J.; Hamon, O.; Leruste, Ph.; Marchiori, G.; Ocariz, J.; Sitt, S.; Biasini, M.; Manoni, E.; Pacetti, S.; Rossi, A.; Angelini, C.; Batignani, G.; Bettarini, S.; Carpinelli, M.; Casarosa, G.; Cervelli, A.; Forti, F.; Giorgi, M. A.; Lusiani, A.; Oberhof, B.; Paoloni, E.; Perez, A.; Rizzo, G.; Walsh, J. J.; Lopes Pegna, D.; Olsen, J.; Smith, A. J. S.; Telnov, A. V.; Anulli, F.; Faccini, R.; Ferrarotto, F.; Ferroni, F.; Gaspero, M.; Li Gioi, L.; Mazzoni, M. A.; Piredda, G.; Bünger, C.; Grünberg, O.; Hartmann, T.; Leddig, T.; Schröder, H.; Voss, C.; Waldi, R.; Adye, T.; Olaiya, E. O.; Wilson, F. F.; Emery, S.; Hamel de Monchenault, G.; Vasseur, G.; Yèche, Ch.; Aston, D.; Bard, D. J.; Bartoldus, R.; Cartaro, C.; Convery, M. R.; Dorfan, J.; Dubois-Felsmann, G. P.; Dunwoodie, W.; Ebert, M.; Field, R. C.; Franco Sevilla, M.; Fulsom, B. G.; Gabareen, A. M.; Graham, M. T.; Grenier, P.; Hast, C.; Innes, W. R.; Kelsey, M. H.; Kim, P.; Kocian, M. L.; Leith, D. W. G. S.; Lewis, P.; Lindquist, B.; Luitz, S.; Luth, V.; Lynch, H. L.; MacFarlane, D. B.; Muller, D. R.; Neal, H.; Nelson, S.; Perl, M.; Pulliam, T.; Ratcliff, B. N.; Roodman, A.; Salnikov, A. A.; Schindler, R. H.; Snyder, A.; Su, D.; Sullivan, M. K.; Va'vra, J.; Wagner, A. P.; Wisniewski, W. J.; Wittgen, M.; Wright, D. H.; Wulsin, H. W.; Young, C. C.; Ziegler, V.; Park, W.; Purohit, M. V.; White, R. M.; Wilson, J. R.; Randle-Conde, A.; Sekula, S. J.; Bellis, M.; Benitez, J. F.; Burchat, P. R.; Miyashita, T. S.; Alam, M. S.; Ernst, J. A.; Gorodeisky, R.; Guttman, N.; Peimer, D. R.; Soffer, A.; Lund, P.; Spanier, S. M.; Eckmann, R.; Ritchie, J. L.; Ruland, A. M.; Schwitters, R. F.; Wray, B. C.; Izen, J. M.; Lou, X. C.; Bianchi, F.; Gamba, D.; Lanceri, L.; Vitale, L.; Martinez-Vidal, F.; Oyanguren, A.; Ahmed, H.; Albert, J.; Banerjee, Sw.; Bernlochner, F. U.; Choi, H. H. F.; King, G. J.; Kowalewski, R.; Lewczuk, M. J.; Nugent, I. M.; Roney, J. M.; Sobie, R. J.; Tasneem, N.; Gershon, T. J.; Harrison, P. F.; Latham, T. E.; Puccio, E. M. T.; Band, H. R.; Dasu, S.; Pan, Y.; Prepost, R.; Wu, S. L.

    2012-09-01

    We use 429fb-1 of e+e- collision data collected at the Υ(4S) resonance with the BABAR detector to measure the radiative transition rate of b→sγ with a sum of 38 exclusive final states. The inclusive branching fraction with a minimum photon energy of 1.9 GeV is found to be B(B¯→Xsγ)=(3.29±0.19±0.48)×10-4 where the first uncertainty is statistical and the second is systematic. We also measure the first and second moments of the photon energy spectrum and extract the best-fit values for the heavy-quark parameters, mb and μπ2, in the kinetic and shape function models.

  5. The All Particle Cosmic-Ray Energy Spectrum Measured with HAWC

    NASA Astrophysics Data System (ADS)

    Hampel-Arias, Zigfried; HAWC Collaboration

    2016-03-01

    We present results of a measurement of the all-particle cosmic-ray energy spectrum above 10 TeV with the High-Altitude Water Cherenkov (HAWC) Observatory. HAWC is a ground based air shower array deployed on the slopes of Volcán Sierra Negra in the state of Puebla, México. It comprises 300 large light-tight water tanks covering an area of 20,000 square meters. Each tank is instrumented with four photomultipliers to detect particles from extensive air showers produced by gamma rays and cosmic rays upon entering the Earth's atmosphere. HAWC is optimized for the detection of gamma-ray induced air showers, yet the background flux of hadronic air showers is four orders of magnitude greater, allowing for a detailed study of the cosmic-ray flux in the TeV energy range. The primary cosmic-ray energy is determined with a maximum likelihood approach using the particle density as a function of distance to the shower core. Introducing quality cuts to isolate events with shower cores landing on the array, the reconstructed energy distribution is unfolded iteratively. We will report on the energy resolution of the technique and the results of the unfolding.

  6. The seismic spectrum, radiated energy, and the Savage and Wood inequality for complex earthquakes

    NASA Astrophysics Data System (ADS)

    Smith, Kenneth D.; Brune, James N.; Priestley, Keith F.

    1991-03-01

    We have integrated velocity squared spectra in order to determine the seismic energy radiated during fault rupture. The high frequency spectral fall-off and the shape of the spectrum at the corner frequency are critical to the energy calculation. High frequency spectral fall-offs of ω-2 beyond the corner frequency, in a Brune (1970) source model, return radiated energies approximately equal to that of an Orowan (1960) type fault failure, where the final stress level is equal to the dynamic frictional stress. Any spectra with an extended intermediate slope of ω-1 would therefore result in higher radiated energies. Savage and Wood (1971) proposed a model in which the final stress level was less than the dynamic stress level and that this was the result of "overshoot". They based their model on the observation that the ratio of twice the apparent stress to the stress drop was typically around 0.3. We show that for such a ratio to exist high frequency spectral fall-offs of ≈ ω-3 would be required. Composite spectra have been constructed for several moderate to large earthquakes, these spectra have been compared to that predicted by the Haskell (1966) model and velocity squared spectra have been integrated to determine the radiated energy. In all cases this ratio, twice the apparent stress to the stress drop, is greater than or equal to one, violating the Savage and Wood (1971) inequality, and provides evidence against "overshoot" as a source model.

  7. The deep space galactic cosmic ray lineal energy spectrum at solar minimum

    NASA Astrophysics Data System (ADS)

    Case, A. W.; Kasper, J. C.; Spence, H. E.; Zeitlin, C. J.; Looper, M. D.; Golightly, M. J.; Schwadron, N. A.; Townsend, L. W.; Mazur, J. E.; Blake, J. B.; Iwata, Y.

    2013-06-01

    The Cosmic Ray Telescope for the Effects of Radiation (CRaTER) instrument is an energetic particle telescope on board the Lunar Reconnaissance Orbiter spacecraft. CRaTER measures energetic charged particles that have sufficient energy to penetrate the outer shielding of the instrument (about 12 MeV/nucleon). Galactic cosmic rays (GCR) with these energies are the primary radiation concern for spacecraft and astronauts outside of the Earth's magnetosphere during times of minimal solar activity. These particles can easily penetrate typical shielding and damage electronics, causing increased electronics failure rates and single event upsets. When this radiation impacts biological cells, it causes an increased risk of cancer. The CRaTER instrument was built to characterize the radiation dose and lineal energy with unprecedented time and energy resolution and was fortuitously flown during a period of time that coincided with the highest GCR fluxes in the modern space age. We report here this worst-case GCR lineal energy spectrum. Observations are made behind a thin aluminum window and different thicknesses of tissue-equivalent plastic. These measurements provide important observational data points to compare with current model predictions of the dose deposited by energetic particles within a tissue-like material.

  8. Variability in fluence and spectrum of high-energy photon bursts produced by lightning leaders

    NASA Astrophysics Data System (ADS)

    Celestin, Sebastien; Xu, Wei; Pasko, Victor P.

    2015-12-01

    In this paper, we model the production and acceleration of thermal runaway electrons during negative corona flash stages of stepping lightning leaders and the corresponding terrestrial gamma ray flashes (TGFs) or negative cloud-to-ground (-CG) lightning-produced X-ray bursts in a unified fashion. We show how the source photon spectrum and fluence depend on the potential drop formed in the lightning leader tip region during corona flash and how the X-ray burst spectrum progressively converges toward typical TGF spectrum as the potential drop increases. Additionally, we show that the number of streamers produced in a negative corona flash, the source electron energy distribution function, the corresponding number of photons, and the photon energy distribution and transport through the atmosphere up to low-orbit satellite altitudes exhibit a very strong dependence on this potential drop. This leads to a threshold effect causing X-rays produced by leaders with potentials lower than those producing typical TGFs extremely unlikely to be detected by low-orbit satellites. Moreover, from the number of photons in X-ray bursts produced by -CGs estimated from ground observations, we show that the proportionality between the number of thermal runaway electrons and the square of the potential drop in the leader tip region during negative corona flash proposed earlier leads to typical photon fluences on the order of 1 ph/cm2 at an altitude of 500 km and a radial distance of 200 km for intracloud lightning discharges producing 300 MV potential drops, which is consistent with observations of TGF fluences and spectra from satellites.

  9. Dependence of the non-linear mass power spectrum on the equationof state of dark energy

    NASA Astrophysics Data System (ADS)

    McDonald, Patrick; Trac, Hy; Contaldi, Carlo

    2006-02-01

    We present N-body simulation calculations of the dependence of the power spectrum of non-linear cosmological mass density fluctuations on the equation of state of the dark energy, w=p/ρ. At fixed linear theory power, increasing w leads to an increase in non-linear power, with the effect increasing with k. By k= 10hMpc-1, a model with w=-0.75 has ~12 per cent more power than a standard cosmological constant model (w=-1), while a model with w=-0.5 has ~33 per cent extra power (at z= 0). The size of the effect increases with increasing dark energy fraction, and to a lesser extent increasing power spectrum normalization, but is insensitive to the power spectrum shape (the numbers above are for Ωm= 0.281 and σ8= 0.897). A code quantifying the non-linear effect of varying w, as a function of k, z and other cosmological parameters, which should be accurate to a few per cent for k<~ 10hMpc-1 for models that fit the current observations, is available at http://www.cita.utoronto.ca/~pmcdonal/code.html. This paper also serves as an example of a detailed exploration of the numerical convergence properties of ratios of power spectra for different models, which can be useful because some kinds of numerical error cancel in a ratio. When precision calculations based on numerical simulations are needed for many different models, efficiency may be gained by breaking the problem into a calculation of the absolute prediction at a central point, and calculations of the relative change in the prediction with model parameters.

  10. Combined Pre-Distortion and Censoring for Bandwidth-Efficient and Energy-Efficient Fusion of Spectrum Sensing Information

    PubMed Central

    Aquino, Guilherme Pedro; Guimarães, Dayan Adionel; Mendes, Luciano Leonel; Pimenta, Tales Cleber

    2017-01-01

    This paper describes a novel scheme for the fusion of spectrum sensing information in cooperative spectrum sensing for cognitive radio applications. The scheme combines a spectrum-efficient, pre-distortion-based fusion strategy with an energy-efficient censoring-based fusion strategy to achieve the combined effect of reduction in bandwidth and power consumption during the transmissions of the local decisions to the fusion center. Expressions for computing the key performance metrics of the spectrum sensing of the proposed scheme are derived and validated by means of computer simulations. An extensive analysis of the overall energy efficiency is made, along with comparisons with reference strategies proposed in the literature. It is demonstrated that the proposed fusion scheme can outperform the energy efficiency attained by these reference strategies. Moreover, it attains approximately the same global decision performance of the best among these strategies. PMID:28327517

  11. Measurement of the energy spectrum of cosmic rays above 1018 eV using the Pierre Auger Observatory

    NASA Astrophysics Data System (ADS)

    Abraham, J.; Abreu, P.; Aglietta, M.; Ahn, E. J.; Allard, D.; Allen, J.; Alvarez-Muñiz, J.; Ambrosio, M.; Anchordoqui, L.; Andringa, S.; Antičić, T.; Anzalone, A.; Aramo, C.; Arganda, E.; Arisaka, K.; Arqueros, F.; Asorey, H.; Assis, P.; Aublin, J.; Ave, M.; Avila, G.; Bäcker, T.; Badagnani, D.; Balzer, M.; Barber, K. B.; Barbosa, A. F.; Barroso, S. L. C.; Baughman, B.; Bauleo, P.; Beatty, J. J.; Becker, B. R.; Becker, K. H.; Bellétoile, A.; Bellido, J. A.; Benzvi, S.; Berat, C.; Bergmann, T.; Bertou, X.; Biermann, P. L.; Billoir, P.; Blanch-Bigas, O.; Blanco, F.; Blanco, M.; Bleve, C.; Blümer, H.; Boháčová, M.; Boncioli, D.; Bonifazi, C.; Bonino, R.; Borodai, N.; Brack, J.; Brogueira, P.; Brown, W. C.; Bruijn, R.; Buchholz, P.; Bueno, A.; Burton, R. E.; Busca, N. G.; Caballero-Mora, K. S.; Caramete, L.; Caruso, R.; Castellina, A.; Catalano, O.; Cataldi, G.; Cazon, L.; Cester, R.; Chauvin, J.; Chiavassa, A.; Chinellato, J. A.; Chou, A.; Chudoba, J.; Clay, R. W.; Colombo, E.; Coluccia, M. R.; Conceição, R.; Contreras, F.; Cook, H.; Cooper, M. J.; Coppens, J.; Cordier, A.; Cotti, U.; Coutu, S.; Covault, C. E.; Creusot, A.; Criss, A.; Cronin, J.; Curutiu, A.; Dagoret-Campagne, S.; Dallier, R.; Daumiller, K.; Dawson, B. R.; de Almeida, R. M.; de Domenico, M.; de Donato, C.; de Jong, S. J.; de La Vega, G.; de Mello Junior, W. J. M.; de Mello Neto, J. R. T.; de Mitri, I.; de Souza, V.; de Vries, K. D.; Decerprit, G.; Del Peral, L.; Deligny, O.; Della Selva, A.; Delle Fratte, C.; Dembinski, H.; di Giulio, C.; Diaz, J. C.; Díaz Castro, M. L.; Diep, P. N.; Dobrigkeit, C.; D'Olivo, J. C.; Dong, P. N.; Dorofeev, A.; Dos Anjos, J. C.; Dova, M. T.; D'Urso, D.; Dutan, I.; Duvernois, M. A.; Ebr, J.; Engel, R.; Erdmann, M.; Escobar, C. O.; Etchegoyen, A.; Facal San Luis, P.; Falcke, H.; Farrar, G.; Fauth, A. C.; Fazzini, N.; Ferrero, A.; Fick, B.; Filevich, A.; Filipčič, A.; Fleck, I.; Fliescher, S.; Fracchiolla, C. E.; Fraenkel, E. D.; Fröhlich, U.; Fulgione, W.; Gamarra, R. F.; Gambetta, S.; García, B.; García Gámez, D.; Garcia-Pinto, D.; Garrido, X.; Gelmini, G.; Gemmeke, H.; Ghia, P. L.; Giaccari, U.; Giller, M.; Glass, H.; Goggin, L. M.; Gold, M. S.; Golup, G.; Gomez Albarracin, F.; Gómez Berisso, M.; Gonçalves, P.; Gonzalez, D.; Gonzalez, J. G.; Góra, D.; Gorgi, A.; Gouffon, P.; Gozzini, S. R.; Grashorn, E.; Grebe, S.; Grigat, M.; Grillo, A. F.; Guardincerri, Y.; Guarino, F.; Guedes, G. P.; Hague, J. D.; Halenka, V.; Hansen, P.; Harari, D.; Harmsma, S.; Harton, J. L.; Haungs, A.; Hebbeker, T.; Heck, D.; Herve, A. E.; Hojvat, C.; Holmes, V. C.; Homola, P.; Hörandel, J. R.; Horneffer, A.; Hrabovský, M.; Huege, T.; Hussain, M.; Iarlori, M.; Insolia, A.; Ionita, F.; Italiano, A.; Jiraskova, S.; Kadija, K.; Kaducak, M.; Kampert, K. H.; Karova, T.; Kasper, P.; Kégl, B.; Keilhauer, B.; Keivani, A.; Kelley, J.; Kemp, E.; Kieckhafer, R. M.; Klages, H. O.; Kleifges, M.; Kleinfeller, J.; Knapik, R.; Knapp, J.; Koang, D.-H.; Krieger, A.; Krömer, O.; Kruppke-Hansen, D.; Kuehn, F.; Kuempel, D.; Kulbartz, K.; Kunka, N.; Kusenko, A.; La Rosa, G.; Lachaud, C.; Lago, B. L.; Lautridou, P.; Leão, M. S. A. B.; Lebrun, D.; Lebrun, P.; Lee, J.; Leigui de Oliveira, M. A.; Lemiere, A.; Letessier-Selvon, A.; Lhenry-Yvon, I.; López, R.; Lopez Agüera, A.; Louedec, K.; Lozano Bahilo, J.; Lucero, A.; Ludwig, M.; Lyberis, H.; Maccarone, M. C.; Macolino, C.; Maldera, S.; Mandat, D.; Mantsch, P.; Mariazzi, A. G.; Marin, V.; Maris, I. C.; Marquez Falcon, H. R.; Marsella, G.; Martello, D.; Martínez Bravo, O.; Mathes, H. J.; Matthews, J.; Matthews, J. A. J.; Matthiae, G.; Maurizio, D.; Mazur, P. O.; McEwen, M.; Medina-Tanco, G.; Melissas, M.; Melo, D.; Menichetti, E.; Menshikov, A.; Meurer, C.; Mičanović, S.; Micheletti, M. I.; Miller, W.; Miramonti, L.; Mollerach, S.; Monasor, M.; Monnier Ragaigne, D.; Montanet, F.; Morales, B.; Morello, C.; Moreno, E.; Moreno, J. C.; Morris, C.; Mostafá, M.; Mueller, S.; Muller, M. A.; Mussa, R.; Navarra, G.; Navarro, J. L.; Navas, S.; Necesal, P.; Nellen, L.; Nhung, P. T.; Nierstenhoefer, N.; Nitz, D.; Nosek, D.; Nožka, L.; Nyklicek, M.; Oehlschläger, J.; Olinto, A.; Oliva, P.; Olmos-Gilbaja, V. M.; Ortiz, M.; Pacheco, N.; Pakk Selmi-Dei, D.; Palatka, M.; Pallotta, J.; Palmieri, N.; Parente, G.; Parizot, E.; Parlati, S.; Parra, A.; Parrisius, J.; Parsons, R. D.; Pastor, S.; Paul, T.; Pavlidou, V.; Payet, K.; Pech, M.; Pȩkala, J.; Pelayo, R.; Pepe, I. M.; Perrone, L.; Pesce, R.; Petermann, E.; Petrera, S.; Petrinca, P.; Petrolini, A.; Petrov, Y.; Petrovic, J.; Pfendner, C.; Piegaia, R.; Pierog, T.; Pimenta, M.; Pirronello, V.; Platino, M.; Ponce, V. H.; Pontz, M.; Privitera, P.; Prouza, M.; Quel, E. J.; Rautenberg, J.; Ravel, O.; Ravignani, D.; Redondo, A.; Revenu, B.; Rezende, F. A. S.; Ridky, J.; Riggi, S.; Risse, M.; Ristori, P.; Rivière, C.; Rizi, V.; Robledo, C.; Rodriguez, G.; Rodriguez Martino, J.; Rodriguez Rojo, J.; Rodriguez-Cabo, I.; Rodríguez-Frías, M. D.; Ros, G.; Rosado, J.; Rossler, T.; Roth, M.; Rouillé-D'Orfeuil, B.; Roulet, E.; Rovero, A. C.; Salamida, F.; Salazar, H.; Salina, G.; Sánchez, F.; Santander, M.; Santo, C. E.; Santos, E.; Santos, E. M.; Sarazin, F.; Sarkar, S.; Sato, R.; Scharf, N.; Scherini, V.; Schieler, H.; Schiffer, P.; Schmidt, A.; Schmidt, F.; Schmidt, T.; Scholten, O.; Schoorlemmer, H.; Schovancova, J.; Schovánek, P.; Schroeder, F.; Schulte, S.; Schüssler, F.; Schuster, D.; Sciutto, S. J.; Scuderi, M.; Segreto, A.; Semikoz, D.; Settimo, M.; Shellard, R. C.; Sidelnik, I.; Siffert, B. B.; Sigl, G.; Śmiałkowski, A.; Šmída, R.; Snow, G. R.; Sommers, P.; Sorokin, J.; Spinka, H.; Squartini, R.; Stasielak, J.; Stephan, M.; Strazzeri, E.; Stutz, A.; Suarez, F.; Suomijärvi, T.; Supanitsky, A. D.; Šuša, T.; Sutherland, M. S.; Swain, J.; Szadkowski, Z.; Tamashiro, A.; Tamburro, A.; Tapia, A.; Tarutina, T.; Taşcău, O.; Tcaciuc, R.; Tcherniakhovski, D.; Tegolo, D.; Thao, N. T.; Thomas, D.; Tiffenberg, J.; Timmermans, C.; Tkaczyk, W.; Todero Peixoto, C. J.; Tomé, B.; Tonachini, A.; Travnicek, P.; Tridapalli, D. B.; Tristram, G.; Trovato, E.; Tueros, M.; Ulrich, R.; Unger, M.; Urban, M.; Valdés Galicia, J. F.; Valiño, I.; Valore, L.; van den Berg, A. M.; Vázquez, J. R.; Vázquez, R. A.; Veberič, D.; Venters, T.; Verzi, V.; Videla, M.; Villaseñor, L.; Vorobiov, S.; Voyvodic, L.; Wahlberg, H.; Wahrlich, P.; Wainberg, O.; Warner, D.; Watson, A. A.; Westerhoff, S.; Whelan, B. J.; Wieczorek, G.; Wiencke, L.; Wilczyńska, B.; Wilczyński, H.; Williams, C.; Winchen, T.; Winnick, M. G.; Wundheiler, B.; Yamamoto, T.; Younk, P.; Yuan, G.; Yushkov, A.; Zas, E.; Zavrtanik, D.; Zavrtanik, M.; Zaw, I.; Zepeda, A.; Ziolkowski, M.; Pierre Auger Collaboration

    2010-03-01

    We report a measurement of the flux of cosmic rays with unprecedented precision and statistics using the Pierre Auger Observatory. Based on fluorescence observations in coincidence with at least one surface detector we derive a spectrum for energies above 1018 eV. We also update the previously published energy spectrum obtained with the surface detector array. The two spectra are combined addressing the systematic uncertainties and, in particular, the influence of the energy resolution on the spectral shape. The spectrum can be described by a broken power law E- with index γ=3.3 below the ankle which is measured at log(E/eV)=18.6. Above the ankle the spectrum is described by a power law with index 2.6 followed by a flux suppression, above about log(E/eV)=19.5, detected with high statistical significance.

  12. Combined Pre-Distortion and Censoring for Bandwidth-Efficient and Energy-Efficient Fusion of Spectrum Sensing Information.

    PubMed

    Aquino, Guilherme Pedro; Guimarães, Dayan Adionel; Mendes, Luciano Leonel; Pimenta, Tales Cleber

    2017-03-22

    This paper describes a novel scheme for the fusion of spectrum sensing information in cooperative spectrum sensing for cognitive radio applications. The scheme combines a spectrum-efficient, pre-distortion-based fusion strategy with an energy-efficient censoring-based fusion strategy to achieve the combined effect of reduction in bandwidth and power consumption during the transmissions of the local decisions to the fusion center. Expressions for computing the key performance metrics of the spectrum sensing of the proposed scheme are derived and validated by means of computer simulations. An extensive analysis of the overall energy efficiency is made, along with comparisons with reference strategies proposed in the literature. It is demonstrated that the proposed fusion scheme can outperform the energy efficiency attained by these reference strategies. Moreover, it attains approximately the same global decision performance of the best among these strategies.

  13. Neutron energy spectrum from 120 GeV protons on a thick copper target

    SciTech Connect

    Shigyo, Nobuhiro; Sanami, Toshiya; Kajimoto, Tsuyoshi; Iwamoto, Yosuke; Hagiwara, Masayuki; Saito, Kiwamu; Ishibashi, Kenji; Nakashima, Hiroshi; Sakamoto, Yukio; Lee, Hee-Seock; Ramberg, Erik; /Fermilab

    2010-08-01

    Neutron energy spectrum from 120 GeV protons on a thick copper target was measured at the Meson Test Beam Facility (MTBF) at Fermi National Accelerator Laboratory. The data allows for evaluation of neutron production process implemented in theoretical simulation codes. It also helps exploring the reasons for some disagreement between calculation results and shielding benchmark data taken at high energy accelerator facilities, since it is evaluated separately from neutron transport. The experiment was carried out using a 120 GeV proton beam of 3E5 protons/spill. Since the spill duration was 4 seconds, protoninduced events were counted pulse by pulse. The intensity was maintained using diffusers and collimators installed in the beam line to MTBF. The protons hit a copper block target the size of which is 5cm x 5cm x 60 cm long. The neutrons produced in the target were measured using NE213 liquid scintillator detectors, placed about 5.5 m away from the target at 30{sup o} and 5 m 90{sup o} with respect to the proton beam axis. The neutron energy was determined by time-of-flight technique using timing difference between the NE213 and a plastic scintillator located just before the target. Neutron detection efficiency of NE213 was determined on basis of experimental data from the high energy neutron beam line at Los Alamos National Laboratory. The neutron spectrum was compared with the results of multiparticle transport codes to validate the implemented theoretical models. The apparatus would be applied to future measurements to obtain a systematic data set for secondary particle production on various target materials.

  14. The High-Energy RXTE X-Ray Spectrum of RX J0852.0-4622

    NASA Astrophysics Data System (ADS)

    Allen, G. E.; Markwardt, C. B.; Petre, R.

    1999-04-01

    A new shell-type supernova remnant, RX J0852.0-4622, was recently discovered in the direction of the Vela remnant. While the Vela remnant dominates the low-energy (ROSAT) X-ray image of this region, the ring of RX J0852.0-4622 is clearly observable at energies > 1.3 keV. This new remnant and the Cas A remnant are the only two sources that have been detected to emit 1.156 MeV gamma rays from the decay of (44) Ti. The presence of (44) Ti, which has a half-life of ~ 90 yr, and the strength of the (44) Ti-line flux indicate that RX J0852.0-4622 is both young ( ~ 600--1100 yr) and close to Earth ( ~ 100--300 pc). Except for the Local Bubble, this remnant may be the closest of the known supernova remnants. A series of scans with the instruments on the RXTE satellite indicate that both the RX J0852.0-4622 and Vela remnants are sources of high-energy X-ray emission. We present the count-rate scan profile and a 3--12 keV RXTE spectrum, which includes emission from both remnants. Although it is difficult to distinguish the RXTE X-ray spectrum of one remnant from the other, spectral models suggest that RX J0852.0-4622 exhibits no evidence of Fe-K--line emission. We discuss whether the high-energy X-ray continuum of this remnant is thermal or non-thermal and review the implications of the results.

  15. Microstructural evolution of pure tungsten neutron irradiated with a mixed energy spectrum

    DOE PAGES

    Koyanagi, Takaaki; Kumar, N. A. P. Kiran; Hwang, Taehyun; ...

    2017-04-13

    Here, microstructures of single-crystal bulk tungsten (W) and polycrystalline W foil with a strong grain texture were investigated using transmission electron microscopy following neutron irradiation at ~90–800 °C to 0.03–4.6 displacements per atom (dpa) in the High Flux Isotope Reactor with a mixed energy spectrum. The dominant irradiation defects were dislocation loops and small clusters at ~90 °C. Additional voids were formed in W irradiated at above 460 °C. Voids and precipitates involving transmutation rhenium and osmium were the dominant defects at more than ~1 dpa. We found a new phenomenon of microstructural evolution in irradiated polycrystalline W: Re- andmore » Os-rich precipitation along grain boundaries. Comparison of results between this study and previous studies using different irradiation facilities revealed that the microstructural evolution of pure W is highly dependent on the neutron energy spectrum in addition to the irradiation temperature and dose.« less

  16. The search for a Hamiltonian whose energy spectrum coincides with the Riemann zeta zeroes

    NASA Astrophysics Data System (ADS)

    Aschheim, Raymond; Perelman, Carlos Castro; Irwin, Klee

    Inspired by the Hilbert-Polya proposal to prove the Riemann Hypothesis we have studied the Schroedinger QM equation involving a highly nontrivial potential, and whose self-adjoint Hamiltonian operator has for its energy spectrum one which approaches the imaginary parts of the zeta zeroes only in the asymptotic (very large N) region. The ordinates λn are the positive imaginary parts of the nontrivial zeta zeroes in the critical line :sn = 1 2 + iλn. The latter results are consistent with the validity of the Bohr-Sommerfeld semi-classical quantization condition. It is shown how one may modify the parameters which define the potential, and fine tune its values, such that the energy spectrum of the (modified) Hamiltonian matches not only the first two zeroes but the other consecutive zeroes. The highly nontrivial functional form of the potential is found via the Bohr-Sommerfeld quantization formula using the full-fledged Riemann-von Mangoldt counting formula (without any truncations) for the number N(E) of zeroes in the critical strip with imaginary part greater than 0 and less than or equal to E.

  17. Energy spectrum and arrival direction of primary cosmic rays of energy above 10 to the 18th power eV

    NASA Technical Reports Server (NTRS)

    Teshima, M.; Nagano, M.; Hayashida, N.; He, C. X.; Honda, M.; Ishikawa, F.; Kamata, K.; Matsubara, Y.; Mori, M.; Ohoka, H.

    1985-01-01

    The observation of ultra high energy cosmic rays with 20 sq km array has started at Akeno. The preliminary results on energy spectrum and arrival direction of energies above 10 to the 18th eV are prsented with data accumulated for four years with the 1 sq km array, for two years with the 4 sq km array and for a half year with the new array. The energy spectrum is consistent with the previous experiments showing the flattening above 10 to the 18.5 eV.

  18. Energy spectrum and mass composition of primary cosmic radiation in the region above the knee from the GAMMA experiment

    NASA Astrophysics Data System (ADS)

    Martirosov, Romen

    The energy spectrum of the primary cosmic radiation in the energy range 1 - 100 PeV and the extensive air shower (EAS) characteristics obtained on the basis of the expanded data bank of the GAMMA experiment (Mt. Aragats, Armenia) are presented. With increased statistics we confirm our previous results on the energy spectrum. The spectral index above the knee is about -3.1, but at energies beyond 20 PeV a flattening of the spectrum is observed. The existence of the 'bump' at about 70 PeV is confirmed with a significance of more than 4{\\sigma}. In the energy range of 10 - 100 PeV the shower age becomes energy independent and we observe a direct proportionality of the EAS size to the primary energy. This suggests an approximately constant depth of the EAS maximum in this energy range. This is evidence in favour of an increasing average mass of primary particles at energies above 20 PeV. The additional source scenario, which is a possible explanation of the 'bump' in the spectrum, also leads to the conclusion of increasing mass of the primary cosmic rays. A comparison with the data of other experiments is presented.

  19. Threshold conditions, energy spectrum and bands generated by locally periodic Dirac comb potentials

    NASA Astrophysics Data System (ADS)

    Dharani, M.; Shastry, C. S.

    2016-01-01

    We derive expressions for polynomials governing the threshold conditions for different types of locally periodic Dirac comb potentials comprising of attractive and combination of attractive and repulsive delta potential terms confined symmetrically inside a one dimensional box of fixed length. The roots of these polynomials specify the conditions on the potential parameters in order to generate threshold energy bound states. The mathematical and numerical methods used by us were first formulated in our earlier works and it is also very briefly summarized in this paper. We report a number of mathematical results pertaining to the threshold conditions and these are useful in controlling the number of negative energy states as desired. We further demonstrate the correlation between the distribution of roots of these polynomials and negative energy eigenvalues. Using these results as basis, we investigate the energy bands in the positive energy spectrum for the above specified Dirac comb potentials and also for the corresponding repulsive case. In the case of attractive Dirac comb the base energy of the each band excluding the first band coincides with specific eigenvalue of the confining box whereas in the repulsive case it coincides with the band top. We deduce systematic correlation between band gaps, band spreads and box eigenvalues and explain the physical reason for the vanishing of band pattern at higher energies. In the case of Dirac comb comprising of orderly arranged attractive and repulsive delta potentials, specific box eigenvalues occur in the middle of each band excluding the first band. From our study we find that by controlling the number and strength parameters of delta terms in the Dirac comb and the size of confining box it is possible to generate desired types of band formations. We believe the results from our systematic analysis are useful and relevant in the study of various one dimensional systems of physical interest in areas like nanoscience.

  20. Fat or lean: adjustment of endogenous energy stores to predictable and unpredictable changes in allostatic load

    USGS Publications Warehouse

    Schultner, Jannik; Kitaysky, Alexander S.; Welcker, Jorg; Hatch, Scott

    2013-01-01

    6. Overall, results of this study support the ‘lean and fit’ hypothesis. We conclude that increased energy stores may not necessarily reflect better environmental conditions experienced by individuals or predict their higher fitness. A major advantage of adopting a lean physique when environmental conditions allow may be the avoidance of additional energetic costs for moving a heavy body. In breeding seabirds, this advantage may be more important during chick-rearing. In the focal species, the secretion of glucocorticoids might be involved in regulation of energy stores within a life history stage but does not appear to mediate an adaptive shift in energy stores between the incubating and chick-rearing stages of reproduction.

  1. RELATIONSHIP BETWEEN THE SHELL-AVERAGED ENERGY SPECTRUM AND THE FREQUENCY SPECTRUM MEASURED BY A SINGLE SPACECRAFT IN THE SOLAR WIND

    SciTech Connect

    Podesta, J. J.

    2009-05-10

    The relationship between the shell-averaged energy spectrum E(k) and the frequency spectrum P(f) measured by a single spacecraft is needed in studies of solar wind turbulence to allow comparisons between theory and experiment. This relationship is derived for a three-dimensional (scalar) wavevector spectrum of the power-law form that is either isotropic or cylindrically symmetric about the mean magnetic field. In the latter case, it is assumed that the power-law exponents in directions parallel and perpendicular to the mean magnetic field are the same, an assumption that allows the analysis to be performed analytically. The results show that the effects of anisotropy are small when the angle {theta} {sub BV} between the solar wind velocity and the mean magnetic field is between approximately 35 deg. and 90 deg. The largest effects occur near 0 deg. where a significant correction factor is needed compared to the isotropic case due to the lower energy in the k {sub ||} direction compared to the k {sub perpendicular} direction. For solar wind spectra with an unknown degree of anisotropy, measurements of E(k) obtained when 35 deg. {<=} {theta} {sub BV} {<=} 90 deg. should be reasonably accurate for most purposes since even if the spectrum is assumed to be isotropic and no corrections are made for spectral anisotropy, the resulting errors are typically less than 10% or 20%.

  2. Measuring the low energy solar neutrino spectrum with the LENS experiment

    NASA Astrophysics Data System (ADS)

    Tayloe, Rex

    2008-10-01

    The Low-Energy Neutrino Spectroscopy (LENS) experiment is designed for a precision measurement in real time of the fluxes of low energy solar neutrinos (pp, ^7Be, pep, and CNO, comprising > 99 % of the solar neutrino energy) via charged-current capture on Indium-115 (with threshold of 114 keV). LENS will allow a comparison of the neutrino and photon luminosities of the sun that will test the basic assumptions of solar astrophysics and the overall validity of the MSW-LMA neutrino model. The individual flux results will improve limits on θ12 and the pp spectrum can directly probe the temperature profile of fusion energy production. A detector technology, utilizing a novel optical segmentation method with indium-loaded liquid scintillator has been developed. A modest 1 m^3 prototype (miniLENS), in development for installation in the Kimballton Underground Research Facility (KURF), will demonstrate experimental feasibility and will allow for optimization for a 200 ton, full-scale LENS experiment.

  3. Novel characteristics of energy spectrum for 3D Dirac oscillator analyzed via Lorentz covariant deformed algebra.

    PubMed

    Betrouche, Malika; Maamache, Mustapha; Choi, Jeong Ryeol

    2013-11-14

    We investigate the Lorentz-covariant deformed algebra for Dirac oscillator problem, which is a generalization of Kempf deformed algebra in 3 + 1 dimension of space-time, where Lorentz symmetry are preserved. The energy spectrum of the system is analyzed by taking advantage of the corresponding wave functions with explicit spin state. We obtained entirely new results from our development based on Kempf algebra in comparison to the studies carried out with the non-Lorentz-covariant deformed one. A novel result of this research is that the quantized relativistic energy of the system in the presence of minimal length cannot grow indefinitely as quantum number n increases, but converges to a finite value, where c is the speed of light and β is a parameter that determines the scale of noncommutativity in space. If we consider the fact that the energy levels of ordinary oscillator is equally spaced, which leads to monotonic growth of quantized energy with the increment of n, this result is very interesting. The physical meaning of this consequence is discussed in detail.

  4. Novel characteristics of energy spectrum for 3D Dirac oscillator analyzed via Lorentz covariant deformed algebra

    PubMed Central

    Betrouche, Malika; Maamache, Mustapha; Choi, Jeong Ryeol

    2013-01-01

    We investigate the Lorentz-covariant deformed algebra for Dirac oscillator problem, which is a generalization of Kempf deformed algebra in 3 + 1 dimension of space-time, where Lorentz symmetry are preserved. The energy spectrum of the system is analyzed by taking advantage of the corresponding wave functions with explicit spin state. We obtained entirely new results from our development based on Kempf algebra in comparison to the studies carried out with the non-Lorentz-covariant deformed one. A novel result of this research is that the quantized relativistic energy of the system in the presence of minimal length cannot grow indefinitely as quantum number n increases, but converges to a finite value, where c is the speed of light and β is a parameter that determines the scale of noncommutativity in space. If we consider the fact that the energy levels of ordinary oscillator is equally spaced, which leads to monotonic growth of quantized energy with the increment of n, this result is very interesting. The physical meaning of this consequence is discussed in detail. PMID:24225900

  5. The influence of adjustment for energy misreporting on relations of cake and cookie intake with cardiometabolic disease risk factors.

    PubMed

    Gottschald, M; Knüppel, S; Boeing, H; Buijsse, B

    2016-11-01

    Previous cohort studies elucidated unexpected inverse relations of cake and cookie (CC) consumption with chronic disease risk. We assessed CC intake in relation to cardiometabolic disease risk factors in a well-phenotyped population with emphasis on misreporting as the potential driving force behind inverse relations. In a cross-sectional EPIC-Potsdam sub-study individual usual CC intake was modeled by combining 24 h recall and food frequency questionnaire data. Cardiometabolic risk factors were anthropometry, blood lipids, blood pressure (BP), physical activity and fitness. Analysis of covariance models adjusted for (i) age/education/lifestyle and (ii) additionally for energy misreporting (ratio of energy intake over energy expenditure) were used to compute mean values of risk factors for quartiles of CC intake. Adjustment for misreporting had considerable impact on relations of CC intake. Initial inverse links with anthropometry were reversed to direct associations. Misreporting adjustment also nullified inverse relations with triglycerides and with total cholesterol in women. Negligible associations with high density lipoprotein cholesterol turned inverse (men: cross-quartile difference (ΔQ4-Q1)=-1.7 mg/dl; women: ΔQ4-Q1=-3.6 mg/dl), so did fitness (men: ΔQ4-Q1=-1.2 ml/kg/min; women: ΔQ4-Q1=-0.9 ml/kg/min). Direct relations with total/low density lipoprotein cholesterol in men were not changed by misreporting (ΔQ4-Q1 max. 7.5 or 11.3 mg/dl). Reduced BP was observed in females with increased CC intake; only systolic BP remained relevant after misreporting adjustment (ΔQ4-Q1=-4.6 mmHg). The strong impact of energy misreporting on relations of CC intake with risk factors emphasizes a careful analysis and interpretation of nutritional data. We showed that apparent favorable relations of CC intake changed with a different model specification, highlighting proper modeling considerations when analyzing diet-disease relations.

  6. Misreporting of energy and micronutrient intake estimated by food records and 24 hour recalls, control and adjustment methods in practice.

    PubMed

    Poslusna, Kamila; Ruprich, Jiri; de Vries, Jeanne H M; Jakubikova, Marie; van't Veer, Pieter

    2009-07-01

    In order to assess nutritional adequacy, valid estimates of nutrient intake are required. One of the main errors in dietary assessment is misreporting. The objective was to review the extent, nature and determinants of misreporting in dietary assessment, how this affects reported intakes of micronutrients and how this is identified and measured, and to identify the best ways of dealing with misreporting when interpreting results. A systematic literature search was conducted for studies of misreporting of dietary intake in adults by 24 hour recalls or by estimated or weighed food records, published up to March 2008. Thirty-seven relevant studies were identified. Possible causes of misreporting were identified. Methods most used to identify misreporting were the Goldberg cut-off (46 % studies) and the doubly labelled water technique (24 % studies). The magnitude of misreporting of energy intake was similar in all three dietary assessment methods. The percentage of under-reporters was about 30 % and energy intake was underestimated by approximately 15 %. Seven papers presented usable data for micronutrient intake. Absolute intakes of Fe, Ca and vitamin C (the three micronutrients addressed in all papers) were on average 30 % lower in low-energy reporters (LER) than that in non-LER and, although results were not consistent, there was a tendency for micronutrient density to be higher in LER. Excluding underreporters or using energy adjustment methods for micronutrient intakes is discussed. Residual method of energy adjustment seems to be a good tool for practice to decrease an influence of misreporting when interpreting results of studies based on food records and 24 hour recalls.

  7. A Theoretical Study of the Runaway Electron Energy Spectrum Inside the High Field Regions of Thunderclouds

    NASA Astrophysics Data System (ADS)

    Cramer, E. S.; Dwyer, J. R.; Arabshahi, S.; Liu, N.; Vodopiyanov, I. B.; Rassoul, H.

    2013-12-01

    Runaway electrons are produced in Earth's atmosphere when the particles rate of energy gain from an externally applied electric field exceeds the rate of energy loss it experiences from various interactions in air. In this presentation, we theoretically study the creation, propagation, and properties of runaway electrons during the avalanche process. Specifically, we use analytical and numerical models to study the runaway electron energy spectrum, and predict its shape and dependence on the electric field strength and air density. We also develop simple relationships between avalanche variables, including the electron avalanche length, radiation length, and minimum runaway electron kinetic energy. In order to guide the calculations presented here, a Monte Carlo simulation code is used, which was created by Dr. Joseph Dwyer at Florida Institute of Technology. The simulation includes all the relevant physics involved in propagating an energetic electron through air under the influence of an electric field. One motivation for this project is to express the results of the Monte Carlo simulation analytically, giving a better perspective on the nature of the avalanche region inside thunderclouds. Although the kinetic theory for runaway electrons has been studied previously (e.g., Roussel-Dupre et al. [1994], and Gurevich et al. [1992]), the equations derived are quite complex. Here, we present a simplified transport equation based on the classical continuity equation in phase space, and develop the proper form for describing the acceleration/deceleration and collisional processes that runaway electrons experience while propagating through air. Analytical results of the steady state distribution are possible with the help of several mathematical techniques, simplifications and assumptions. In particular, we find that when the bremsstrahlung energy losses are included, the high energy portion of the electron distribution is greatly affected. Finally, a numerical solution

  8. Measurement of the Transverse Energy Spectrum in Proton-Nucleon Collisions.

    NASA Astrophysics Data System (ADS)

    Bettoni, Diego

    We describe a measurement of the transverse energy spectrum in proton-nucleon interactions carried out at the CERN SPS using the HELIOS spectrometer. The measurement is of particular interest in that it is performed in a rapidity region away from central rapidity, where experimental data is scarce. In this rapidity region very interesting physics is anticipated and the measurement of the proton -nucleon collisions is essential as a basis to understand the more complicated proton-nucleus and nucleus-nucleus interactions. Both these topics are part of the experimental programme of HELIOS. The measurement was done using a deuterium target enclosed in an iron tube. The contribution to the transverse energy spectrum from the p-Fe events is discriminated against by reconstructing the primary interaction vertex using drift chamber information. The measured spectrum is corrected via Monte Carlo to deconvolute the effect of reinteractions. We also report, in the first part of the thesis, on the author's contribution to the development of the high-resolution drift chambers employed in the HELIOS detector. High spatial resolution and multi-track resolving power are achieved with the use of a cool gas, such that the electron characteristic energy is close to the thermal limit: this implies a small diffusion coefficient and a consequently good positional accuracy. Of vital importance are the low value of the drift velocity, the fast, differentiating electronics and a careful shaping of the electric field configuration to improve the isochrony of the drift collection. We report on the design and tests of drift chamber prototypes built along the above lines, with which a spatial accuracy of 0.06 mm and a double track resolution of 0.6 mm were measured. We also describe the final drift chamber system and its operation in HELIOS, and we point out the great care with which all systematic effects must be kept under control. The author's personal contribution to this work has been the

  9. Turbulence in the solar wind: what controls the slope of the energy spectrum?

    NASA Astrophysics Data System (ADS)

    Verdini, Andrea; Grappin, Roland

    2016-04-01

    The spectrum of solar wind fluctuations is well described by a power law with an average spectral index -5/3 for periods between a few hours and a few minutes. However, the spectral index varies with stream speed and with the correlation of velocity and magnetic field fluctuations (Alfvénicity): the spectrum is softer in fast and Alfvénic streams. Roughly, this variation can be understood in term of the turbulent age of fluctuations at a given scale: the faster is the wind or the stronger is the correlation than the younger is the turbulence. Since the coronal spectrum is supposed to be rather flat (at least in the fast solar wind), smaller spectral indices correspond to less evolved spectra. According to this interpretation, one would expect spectral slope to change with distance as the turbulence ages, while observations report fairly stable spectral slopes. In order to quantify the effect of wind speed and Alfvénicity on the spectral slope, we ran a series of numerical simulations of MHD turbulence in the framework of the Expanding Box Model (EBM). In EBM we can vary the expansion rate and the initial correlation of fluctuations so as to investigate the existence of a threshold value for each parameter or for a combination of the two that could explain the observed variation and stability of the spectral index. We present preliminary results that indicate that the expansion rate does control the spectral index of energy when the Alfvénicity is high.

  10. Analytic spectrum of relic gravitational waves modified by neutrino free streaming and dark energy

    SciTech Connect

    Miao, H. X.; Zhang, Y.

    2007-05-15

    We include the effect of neutrino free streaming into the spectrum of relic gravitational waves (RGWs) in the currently accelerating universe. For the realistic case of a varying fractional neutrino energy density and a nonvanishing derivative of the mode function at the neutrino decoupling, the integro-differential equation of RGWs is solved by a perturbation method for the period from the neutrino decoupling to the matter-dominant stage. Incorporating it into the analytic solution of RGWs for the whole history of expansion of the universe, the analytic solution of RGWs is obtained, evolving from inflation up to the current acceleration. The resulting spectrum of RGWs covers the whole range of frequency (10{sup -19}-10{sup 10}) Hz and improves the previous results. It is found that neutrino free streaming causes a reduction of the spectral amplitude by {approx}20% in the range (10{sup -16}-10{sup -10}) Hz, and leaves the other portion of the spectrum almost unchanged. This agrees with the earlier numerical calculations. Examination is made on the difference between the accelerating and nonaccelerating models, and our analysis shows that the ratio of the spectral amplitude in the accelerating {lambda}CDM model over that in the CDM model is {approx}0.7, and within the various accelerating models of {omega}{sub {lambda}}>{omega}{sub m} the spectral amplitude is proportional to {omega}{sub m}/{omega}{sub {lambda}} for the whole range of frequency. Comparison with LIGO S5 run sensitivity shows that RGWs are not yet detectable by the present LIGO, and in the future LISA may be able to detect RGWs in some inflationary models.

  11. Chandra Low Energy Transmission Grating Spectrum of SS Cygni in Outburst

    NASA Astrophysics Data System (ADS)

    Mauche, Christopher W.

    2004-07-01

    We have fitted the Chandra Low Energy Transmission Grating (LETG) spectrum of SS Cygni in outburst with a single-temperature blackbody suffering the photoelectric opacity of a neutral column density and the scattering opacity of an outflowing wind. We find that this simple model is capable of reproducing the essential features of the observed spectrum with the blackbody temperature Tbl~250+/-50 kK, hydrogen column density NH~5.0+2.9-1.5×1019cm-2, fractional emitting area f~5.6+60-4.5×10-3, boundary layer luminosity Lbl~5+18-3×1033ergss-1, wind velocity v~2500kms-1, wind mass-loss rate Mw~1.1×1016gs-1, and arbitrary values of the wind ionization fractions of 20 ions of O, Ne, Mg, Si, S, and Fe. Given that in outburst the accretion disk luminosity Ldisk~1×1035ergss-1, Lbl/Ldisk~0.05+0.18-0.03, which can be explained if the white dwarf (or an equatorial belt thereon) is rotating with an angular velocity Ωwd~0.7+0.1-0.2 Hz, hence Vrotsini~2300kms-1. This paper is dedicated to the memory and accomplishments of my colleague and friend Janet Akyüz Mattei, who died on 2004 March 22 after a long battle with acute myelogenous leukemia. Her passing is a great loss to the astronomical community, both amateur and professional.

  12. Estimates of the DT Fusion Gamma Spectrum Using an Energy Thresholding Gas Cherenkov Detector

    NASA Astrophysics Data System (ADS)

    Horsfield, Colin; Rubery, Michael; Hans, Herrmann; Mack, Joseph; Young, Carl; Caldwell, Steven; Scott, Evans; Sedillo, Thomas; Kim, Yongho; Hale, Gerry; Shah, Rahul; Kirk, Miller; Wolfgang, Stoefll

    2011-10-01

    In addition to alphas and neutrons, the DT fusion reaction also produces gamma rays from the intermediate excited 5He nucleus with a small branching ratio 10E-5 gamma/n. The very small branching ratio of the gamma-rays are mitigated by the very large yields that are expected on NIF (10E+19). The excited 5He can produce gamma-rays by decay to the ground state, emitting a 16.75 MeV gamma-ray (width 0.5 MeV), or to a broad first excited state emitting a 12 MeV gamma ray (width 5 MeV). Knowledge of the relative gamma-ray BR of these two states, from which we infer the DT gamma ray spectrum, is important to making absolutely calibrated measurements on a variety of experiments. We have carried out an energy thresh-holding experiment for DT ICF implosions on the Omega laser using a Gas Cherenkov Detector, and compared the relative intensities at various thresholds with theoretical gamma spectra folded with detector response as calculated by ACCEPT and GEANT4 codes. We present recent results from this experiment, our estimate of the precision of the DT fusion gamma spectrum and the implications for the future determination of the DT gamma/n BR.

  13. Scaling of heat flux and energy spectrum for very large Prandtl number convection.

    PubMed

    Pandey, Ambrish; Verma, Mahendra K; Mishra, Pankaj K

    2014-02-01

    Under the limit of infinite Prandtl number, we derive analytical expressions for the large-scale quantities, e.g., Péclet number Pe, Nusselt number Nu, and rms value of the temperature fluctuations θ(rms). We complement the analytical work with direct numerical simulations, and show that Nu ∼ Ra(γ) with γ ≈ (0.30-0.32), Pe ∼ Ra(η) with η ≈ (0.57-0.61), and θ(rms) ∼ const. The Nusselt number is observed to be an intricate function of Pe, θ(rms), and a correlation function between the vertical velocity and temperature. Using the scaling of large-scale fields, we show that the energy spectrum E(u)(k) ∼ k(-13/3), which is in a very good agreement with our numerical results. The entropy spectrum E(θ)(k), however, exhibits dual branches consisting of k(-2) and k(0) spectra; the k(-2) branch corresponds to the Fourier modes θ[over ̂](0,0,2n), which are approximately -1/(2 nπ). The scaling relations for Prandtl number beyond 10(2) match with those for infinite Prandtl number.

  14. Less-energy-dense diets of low-income women in California are associated with higher energy-adjusted diet costs.

    PubMed

    Townsend, Marilyn S; Aaron, Grant J; Monsivais, Pablo; Keim, Nancy L; Drewnowski, Adam

    2009-04-01

    US-based studies are needed to estimate the relation, if any, between diet quality and estimated diet costs. We hypothesized that lower cost diets among low-income women in California would be energy dense but nutrient poor. Energy and nutrient intakes for 112 women aged 18-45 y living in California were obtained with a food-frequency instrument. Dietary energy density (in MJ/kg or kcal/g) and energy-adjusted diet costs (in $/10 MJ or $/2000 kcal) were calculated with local food prices. Tertile splits of energy density and energy cost were analyzed with one-factor analysis of variance. Mean daily energy intake excluding all beverages was 7.1 MJ (1699 kcal), and mean dietary energy density was 6.5 kJ/kg (1.54 kcal/g). Lower dietary energy density was associated with significantly higher intakes of dietary fiber (P = 0.004), vitamin A (P < 0.001), and vitamin C (P < 0.001) and with significantly lower intakes of total fat (P = 0.003) and saturated fat (P < 0.001). Higher diet cost was associated with significantly lower dietary energy density (P < 0.001), total fat (P = 0.024), and saturated fat (P = 0.025) and with significantly higher intakes of vitamins A (P = 0.003) and C (P < 0.001). Each additional dollar in estimated diet costs was associated with a drop in energy density of 0.94 MJ/kg (0.225 kcal/g). The finding that higher quality diets were more costly for these low-income women has implications for the food assistance and education programs of the US Department of Agriculture. Policy interventions may be required to allow low-income families in the United States to improve the quality of their diets given their food budget constraints.

  15. Energy spectrum of cascade showers induced by cosmic ray muons in the range from 50 GeV to 5 TeV

    NASA Technical Reports Server (NTRS)

    Ashitkov, V. D.; Kirina, T. M.; Klimakov, A. P.; Kokoulin, R. P.; Petrukhin, A. A.; Yumatov, V. I.

    1985-01-01

    The energy spectrum of cascade showers induced by electromagnetic interactions of high energy muons of horizontal cosmic ray flux in iron absorber was measured. The total observation time exceeded 22,000 hours. Both the energy spectrum and angular distributions of cascade showers are fairly described in terms of the usual muon generation processes, with a single power index of the parent meson spectrum over the muon energy range from 150 GeV to 5 TeV.

  16. Effects of live weight adjusted feeding strategy on plasma indicators of energy balance in Holstein cows managed for extended lactation.

    PubMed

    Gaillard, C; Vestergaard, M; Weisbjerg, M R; Sehested, J

    2016-04-01

    In early lactation, most of the dairy cows are in negative energy balance; the extent and duration depend in part on the feeding strategy. Previous studies showed an increased lactation milk yield by use of a live weight (LW) adjusted feeding strategy with a high energy diet before and a reduced energy diet after LW nadir compared with a standard diet throughout lactation. The objective of the present study was to examine how such an individualized feeding strategy affects plasma indicators of energy status. It was hypothesized that an energy-enriched diet until LW nadir will reduce the severity of the negative energy balance, and that the reduction in diet energy concentration from LW nadir will extend the negative energy balance period further. Sixty-two Holstein cows (30% first parity) were managed for 16 months extended lactation and randomly allocated to one of two feeding strategies at calving. Two partially mixed rations were used, one with a high energy density (HD) and a 50 : 50 forage : concentrate ratio, and one with a lower energy density (LD, control diet) and a 60 : 40 forage : concentrate ratio. Half of the cows were offered the HD diet until they reached at least 42 days in milk and a LW gain⩾0 kg/day based on a 5-days LW average, and were then shifted to the LD diet (strategy HD-LD). The other half of the cows were offered the LD diet throughout lactation (control strategy LD-LD). Weekly blood samples were drawn for analysis of plasma metabolites and hormones. Before the shift in diet, the HD-LD cows had higher glucose and lower beta-hydroxybutyrate and non-esterified fatty acids (NEFA) concentrations than the LD-LD cows. After the shift until 36 weeks after calving, plasma NEFA was higher in HD-LD than LD-LD cows. Insulin and insulin-like growth factor-1 were not affected by the feeding strategy. To conclude, in early lactation, the energy-enriched diet reduced the negative energy balance. Plasma NEFA was higher in HD-LD than LD-LD cows from

  17. Energy spectrum of a 2D Dirac oscillator in the presence of a constant magnetic field and an antidot potential

    NASA Astrophysics Data System (ADS)

    Akcay, Huseyin; Sever, Ramazan

    2016-07-01

    We investigate the energy spectrum and the corresponding eigenfunctions of a 2D Dirac oscillator confined by an antidot potential in the presence of a magnetic field and Aharonov-Bohm flux field. Analytical solutions are obtained and compared with the results of the Schrödinger equation found in the literature. Further, the dependence of the spectrum on the magnetic quantum number and on the repulsive potential is discussed.

  18. Spread Spectrum Based Energy Efficient Collaborative Communication in Wireless Sensor Networks.

    PubMed

    Ghani, Anwar; Naqvi, Husnain; Sher, Muhammad; Khan, Muazzam Ali; Khan, Imran; Irshad, Azeem

    2016-01-01

    Wireless sensor networks consist of resource limited devices. Most crucial of these resources is battery life, as in most applications like battle field or volcanic area monitoring, it is often impossible to replace or recharge the power source. This article presents an energy efficient collaborative communication system based on spread spectrum to achieve energy efficiency as well as immunity against jamming, natural interference, noise suppression and universal frequency reuse. Performance of the proposed system is evaluated using the received signal power, bit error rate (BER) and energy consumption. The results show a direct proportionality between the power gain and the number of collaborative nodes as well as BER and signal-to-noise ratio (Eb/N0). The analytical and simulation results of the proposed system are compared with SISO system. The comparison reveals that SISO perform better than collaborative communication in case of small distances whereas collaborative communication performs better than SISO in case of long distances. On the basis of these results it is safe to conclude that collaborative communication in wireless sensor networks using wideband systems improves the life time of nodes in the networks thereby prolonging the network's life time.

  19. High time resolution electron measurement by Fast Electron energy Spectrum Analyzer (FESA)

    SciTech Connect

    Saito, Yoshifumi; Fujimoto, Masaki; Maezawa, Kiyoshi; Shinohara, Iku; Tsuda, Yuichi; Sasaki, Shintaro; Kojima, Hirotsugu

    2009-06-16

    We have newly developed an electron energy analyzer FESA (Fast Electron energy Spectrum Analyzer) for a future magnetospheric satellite mission SCOPE. The SCOPE mission is designed in order that observational studies from the cross-scale coupling viewpoint are enabled. One of the key observations necessary for the SCOPE mission is high-time resolution electron measurement. Eight FESAs on a spinning spacecraft are capable of measuring three dimensional electron distribution function with time resolution of 8 msec. FESA consists of two electrostatic analyzers that are composed of three nested hemispherical deflectors. Single FESA functions as four top-hat type electrostatic analyzers that can measure electrons with four different energies simultaneously. By measuring the characteristics of the test model FESA, we proved the validity of the design concept of FESA. Based on the measured characteristics, we designed FESA optimized for the SCOPE mission. This optimized analyzer has good enough performance to measure three dimensional electron distribution functions around the magnetic reconnection region in the Earth's magnetotail.

  20. Equilibrium energy spectrum of point vortex motion with remarks on ensemble choice and ergodicity

    NASA Astrophysics Data System (ADS)

    Esler, J. G.

    2017-01-01

    The dynamics and statistical mechanics of N chaotically evolving point vortices in the doubly periodic domain are revisited. The selection of the correct microcanonical ensemble for the system is first investigated. The numerical results of Weiss and McWilliams [Phys. Fluids A 3, 835 (1991), 10.1063/1.858014], who argued that the point vortex system with N =6 is nonergodic because of an apparent discrepancy between ensemble averages and dynamical time averages, are shown to be due to an incorrect ensemble definition. When the correct microcanonical ensemble is sampled, accounting for the vortex momentum constraint, time averages obtained from direct numerical simulation agree with ensemble averages within the sampling error of each calculation, i.e., there is no numerical evidence for nonergodicity. Further, in the N →∞ limit it is shown that the vortex momentum no longer constrains the long-time dynamics and therefore that the correct microcanonical ensemble for statistical mechanics is that associated with the entire constant energy hypersurface in phase space. Next, a recently developed technique is used to generate an explicit formula for the density of states function for the system, including for arbitrary distributions of vortex circulations. Exact formulas for the equilibrium energy spectrum, and for the probability density function of the energy in each Fourier mode, are then obtained. Results are compared with a series of direct numerical simulations with N =50 and excellent agreement is found, confirming the relevance of the results for interpretation of quantum and classical two-dimensional turbulence.

  1. Spread Spectrum Based Energy Efficient Collaborative Communication in Wireless Sensor Networks

    PubMed Central

    2016-01-01

    Wireless sensor networks consist of resource limited devices. Most crucial of these resources is battery life, as in most applications like battle field or volcanic area monitoring, it is often impossible to replace or recharge the power source. This article presents an energy efficient collaborative communication system based on spread spectrum to achieve energy efficiency as well as immunity against jamming, natural interference, noise suppression and universal frequency reuse. Performance of the proposed system is evaluated using the received signal power, bit error rate (BER) and energy consumption. The results show a direct proportionality between the power gain and the number of collaborative nodes as well as BER and signal-to-noise ratio (Eb/N0). The analytical and simulation results of the proposed system are compared with SISO system. The comparison reveals that SISO perform better than collaborative communication in case of small distances whereas collaborative communication performs better than SISO in case of long distances. On the basis of these results it is safe to conclude that collaborative communication in wireless sensor networks using wideband systems improves the life time of nodes in the networks thereby prolonging the network’s life time. PMID:27447489

  2. LDEF (Prelaunch), M0002-01 : Trapped-Proton Energy Spectrum Determination, Tray G12

    NASA Technical Reports Server (NTRS)

    1984-01-01

    The prelaunch photograph was taken in SAEF II at KSC prior to installation of the integrated tray on the LDEF. The Trapped Proton Energy Spectrum Determination Experiment is one of four (4) experiments located in a three (3) inch deep LDEF end center tray. Additional Trapped Proton Energy Experiments are located in peripheral LDEF integrated experiment trays in the D03 and D09 tray locations. The identifica tion plate on the lower right corner of the experiment mounting plate identifies the experiments location and orientation in the experiment tray. The Trapped Proton Energy experiment, located in the upper left quadrant of the integrated tray, consist of a primary experiment and three (3) sub experiments mounted on an aluminum mount ing plate. The primary experiment components include six (6) stacks of CR-39 passive detectors in individual aluminum housings and an aluminum mounting structure, configured to provide the desired exposure for the detector stacks. The secondary experiments consist of the Neutron and Proton Activation experiment that expose metal samples to the ambient flux throughout the mis sion, the Microsphere Dosimetry experiment housed in a cylindrical aluminum container and the Flux Measurement by Ion Trapping experiment consisting of a variety of sample materials that are exposed to the space environment for the total mission. The exterior surfaces of the mounting plate, the experiment housings and the support structure are coated with IITRI S13G-LO white paint.The experiment is assembled using non-magnetic stainless steel fasteners and safety wire.

  3. Absolutely continuous energy bands in the electronic spectrum of quasiperiodic ladder networks

    NASA Astrophysics Data System (ADS)

    Pal, Biplab; Chakrabarti, Arunava

    2014-06-01

    The energy spectra of quasi-one-dimensional quasiperiodic ladder networks are analyzed within a tight binding description. In particular, we show that if a selected set of sites in each strand of a ladder is tunnel-coupled to quantum dots attached from a side, absolutely continuous subbands can be generated in the spectrum if one tunes the dot potential and the dot-strand coupling appropriately. Typical cases with two and three strand Fibonacci ladders in the off-diagonal model are discussed in details. We also discuss the possibility of re-entrant insulator-metal transition for a general n-strand ladder network when n becomes large. The observations remain valid even in the case of a disordered ladder network with the same constituents. The results are analytically exact.

  4. Study of the primary cosmic ray composition around the knee of the energy spectrum

    NASA Astrophysics Data System (ADS)

    Aglietta, M.; Alessandro, B.; Antonioli, P.; Arneodo, F.; Bergamasco, L.; Bertaina, M.; Fauth, A. Campos; Castagnoli, C.; Castellina, A.; Cattadori, C.; Chiavassa, A.; Cini, G.; D'Ettorre Piazzoli, B.; Di Sciascio, G.; Fulgione, W.; Galeotti, P.; Ghia, P. L.; Iacovacci, M.; Mannocchi, G.; Melagrana, C.; Morello, C.; Navarra, G.; Riccati, L.; Saavedra, O.; Trinchero, G. C.; Vallania, P.; Vernetto, S.; Ahlen, S.; Ambrosio, M.; Antolini, R.; Auriemma, G.; Baker, R.; Baldini, A.; Barbarino, G. C.; Barish, B. C.; Battistoni, G.; Bellotti, R.; Bemporad, C.; Bernardini, P.; Bilokon, H.; Bisi, V.; Bloise, C.; Bower, C.; Bussino, S.; Cafagna, F.; Calicchio, M.; Campana, D.; Carboni, M.; Cecchini, S.; Cei, F.; Chiarella, V.; Cormack, R.; Corona, A.; Coutu, S.; DeCataldo, G.; Dekhissi, H.; DeMarzo, C.; De Mitri, M.; De Vincenzi, M.; Di Credico, A.; Diehl, E.; Erriquez, O.; Favuzzi, C.; Ficenec, D.; Forti, C.; Fusco, P.; Giacomelli, G.; Giannini, G.; Giglietto, N.; Goretti, M.; Grassi, M.; Green, P.; Grillo, A.; Guarino, F.; Guarnaccia, P.; Gustavino, C.; Habig, A.; Hanson, K.; Heinz, R.; Hong, J. T.; Iarocci, E.; Katsavounidis, E.; Kearns, E.; Klein, S.; Kyriazopoulou, S.; Lamanna, E.; Lane, C.; Levin, D. S.; Lipari, P.; Liu, G.; Liu, R.; Longo, M. J.; Lu, Y.; Ludlam, G.; Mancarella, G.; Mandrioli, G.; Margiotta-Neri, A.; Marin, A.; Marini, A.; Martello, D.; Chiesa, A. Marzari; Matteuzzi, P.; Mazziotta, M. N.; Michael, D. G.; Mikheyev, S.; Miller, L.; Mittelbrun, M.; Monacelli, P.; Montaruli, T.; Monteno, M.; Mufson, S.; Musser, J.; Nicoló, D.; Nolty, R.; Nutter, S.; Okada, C.; Osteria, G.; Palamara, O.; Parlati, S.; Patera, V.; Patrizii, L.; Pavesi, B.; Pazzi, R.; Peck, C. W.; Petrakis, J.; Petrera, S.; Pignatano, N. D.; Pistilli, P.; Rainó, A.; Reynoldson, J.; Ronga, F.; Sanzani, G.; Sanzgiri, A.; Sartogo, F.; Satriano, C.; Satta, L.; Scapparone, E.; Scholberg, K.; Sciubba, A.; Lugaresi, P. Serra; Severi, M.; Sitta, M.; Spinelli, P.; Spinetti, M.; Spurio, M.; Steele, J.; Steinberg, R.; Stone, J. L.; Sulak, L. R.; Surdo, A.; Tarlé, G.; Togo, V.; Valente, V.; Walter, C. W.; Webb, R.; Worstell, W.

    1994-10-01

    A study of the primary cosmic ray composition in the energy range 5ṡ10 14-5ṡ10 15 eV is performed through the analysis of the deep underground muons and of the e.m. component of Extensive Air Showers detected in coincidence by the MACRO and EAS-TOP experiments at the Gran Sasso Laboratory. We conclude that: a) pure proton and Iron primary beams are excluded by the experimental data; b) a fraction of nuclei heavier than Helium is necessary to explain the experimental data both below and above the knee; c) a mixed composition, obtained a priori from extrapolations of the spectra directly measured below 100 TeV, yields a reasonable account of the observations up to the knee of the primary spectrum.

  5. Polynomial potentials determined from the energy spectrum and transition dipole moments that give the largest hyperpolarizabilities

    NASA Astrophysics Data System (ADS)

    Dawson, Nathan J.; Kuzyk, Mark G.

    2016-12-01

    We attempt to get a polynomial solution to the inverse problem, that is, to determine the form of the mechanical Hamiltonian when given the energy spectrum and transition dipole moment matrix. Our approach is to determine the potential in the form of a polynomial by finding an approximate solution to the inverse problem, then to determine the hyperpolarizability for that system's Hamiltonian. We find that the largest hyperpolarizabilities approach the apparent limit of previous potential optimization studies, but we do not find real potentials for the parameter values necessary to exceed this apparent limit. We also explore half potentials with positive exponent, which cannot be expressed as a polynomial except for integer powers. This yields a simple closed potential with only one parameter that scans nearly the full range of the intrinsic hyperpolarizability. The limiting case of vanishing exponent yields the largest intrinsic hyperpolarizability.

  6. A method of dopant electron energy spectrum parameterization for calculation of single-electron nanodevices

    NASA Astrophysics Data System (ADS)

    Shorokhov, V. V.

    2017-05-01

    Solitary dopants in semiconductors and dielectrics that possess stable electron structures and interesting physical properties may be used as building blocks of quantum computers and sensor systems that operate based on new physical principles. This study proposes a phenomenological method of parameterization for a single-particle energy spectrum of dopant valence electrons in crystalline semiconductors and dielectrics that takes electron-electron interactions into account. It is proposed to take electron-electron interactions in the framework of the outer electron shell model into account. The proposed method is applied to construct the procedure for the determination of the effective dopant outer shell capacity and the method for calculation of the tunneling current in a single-electron device with one or several active dopants-charge centers.

  7. High-energy x-ray backlighter spectrum measurements using calibrated image plates

    SciTech Connect

    Maddox, B.R.; Park, H.S.; Remington, B.A.; Izumi, N.; Chen, S.; Chen, C.; Kimminau, G.; Ali, Z.; Haugh, M.J.; Ma, Q.

    2012-10-10

    The x-ray spectrum between 18 and 88 keV generated by a petawatt laser driven x-ray backlighter target was measured using a 12-channel differential filter pair spectrometer. The spectrometer consists of a series of filter pairs on a Ta mask coupled with an x-ray sensitive image plate. A calibration of Fuji{trademark} MS and SR image plates was conducted using a tungsten anode x-ray source and the resulting calibration applied to the design of the Ross pair spectrometer. Additionally, the fade rate and resolution of the image plate system were measured for quantitative radiographic applications. The conversion efficiency of laser energy into silver K{alpha} x rays from a petawatt laser target was measured using the differential filter pair spectrometer and compared to measurements using a single photon counting charge coupled device.

  8. The Energy Spectrum of X-Rays from Rocket-triggered Lightning

    NASA Astrophysics Data System (ADS)

    Arabshahi, S.; Cramer, E. S.; Dwyer, J. R.; Grove, J.; Gwon, C.; Hill, J. D.; Jordan, D. M.; Lucia, R. J.; Rassoul, H. K.; Uman, M. A.

    2012-12-01

    Although the production of x-rays from natural and rocket-triggered lightning leaders has been studied in detail over the last ten years, the energy spectrum of the x-rays has never been well measured because the x-rays are emitted in very short but intense bursts that result in pulse pile-up in the detectors. The energy spectrum is important because it provides information about the source mechanism for producing the energetic runaway electrons and about the electric fields that they traversed. We have recently developed and operated the first spectrometer for the energetic radiation from lightning during the spring of 2012. The instrument is part of the Atmospheric Radiation Imagery and Spectroscopy (ARIS) project and will be referred to as "ARIS-S" (ARIS Spectrometer). The instrument consisted of seven 3" NaI(Tl)/photomultiplier tube (PMT) scintillation detectors with different layers of shielding, ranging from 1/8" of Al to more than 1" thickness of lead. Great care was taken to reduce spurious signals from the electrically noisy environment near lightning. The spectrometer was located about 27 meters horizontally from the rocket launcher at the International Center for Lightning Research and Testing (ICLRT). We will present the details of the design of the instrument and the results of analyzing the lightning data acquired during the summer 2012. This work was supported in part by DARPA grant HR0011-1-10-1-0061. Portions of this work were performed at NRL under sponsorship of the Office of Naval Research.

  9. THE {gamma}-RAY SPECTRUM OF GEMINGA AND THE INVERSE COMPTON MODEL OF PULSAR HIGH-ENERGY EMISSION

    SciTech Connect

    Lyutikov, Maxim

    2012-09-20

    We reanalyze the Fermi spectra of the Geminga and Vela pulsars. We find that the spectrum of Geminga above the break is well approximated by a simple power law without the exponential cutoff, making Geminga's spectrum similar to that of Crab. Vela's broadband {gamma}-ray spectrum is equally well fit with both the exponential cutoff and the double power-law shapes. In the broadband double power-law fits, for a typical Fermi spectrum of a bright {gamma}-ray pulsar, most of the errors accumulate due to the arbitrary parameterization of the spectral roll-off. In addition, a power law with an exponential cutoff gives an acceptable fit for the underlying double power-law spectrum for a very broad range of parameters, making such fitting procedures insensitive to the underlying Fermi photon spectrum. Our results have important implications for the mechanism of pulsar high-energy emission. A number of observed properties of {gamma}-ray pulsars-i.e., the broken power-law spectra without exponential cutoffs and stretching in the case of Crab beyond the maximal curvature limit, spectral breaks close to or exceeding the maximal breaks due to curvature emission, patterns of the relative intensities of the leading and trailing pulses in the Crab repeated in the X-ray and {gamma}-ray regions, presence of profile peaks at lower energies aligned with {gamma}-ray peaks-all point to the inverse Compton origin of the high-energy emission from majority of pulsars.

  10. Energy and air emissions embodied in China-U.S. trade: eastbound assessment using adjusted bilateral trade data.

    PubMed

    Xu, Ming; Allenby, Braden; Chen, Weiqiang

    2009-05-01

    It is critical to understand environmental impacts embodied in the bilateral trade between China and the United States, given the political, economic, and geographical importance of the two countries and the fact that few studies have investigated this before. This article studies the environmental impacts, particularly energy consumption and air emissions, embodied in the eastbound (from China to the U.S.) trade from 2002 to 2007 using an environmental input-output analysis technique and the adjusted bilateral trade data. In general,trade volume increased until the panic of 2008, and shifting trade patterns cause fluctuating embodied energy and air emissions in trade in China. Results show that embodied energy ranges from 7 to 11 exajoule (EJ) and takes about 12-17% of China's energy consumption. Embodied CO2 ranges between 400 and 800 Mt and represents about 8-12% of China's CO2 emissions. SO2 and NOx embodied in the eastbound trade generally grow over this period, from 4.2 to 6.3 Mt and from 1.4 to 2.9 Mt and account for 10-15% and 8-12% of China's total emissions, respectively.

  11. Energy spectrum and flux of 3- to 20-Mev neutrons and 1- to 10-Mev gamma rays in the atmosphere

    NASA Technical Reports Server (NTRS)

    Klumpar, D. M.; Lockwood, J. A.; Saint Onge, R. N.; Friling, L. A.

    1973-01-01

    An experiment is described which was designed to measure the neutron and gamma ray energy spectrums and fluxes in the energy intervals 3 to 20 MeV and 1 to 10 MeV, respectively. In addition, from the 3 to 20-MeV proton recoil spectrums it is possible to infer the shape of the neutron energy spectrum from 20 to 50 MeV. The detecting system utilized a separate charged particle rejection scheme and a two-parameter display system for the output from the pulse shape discrimination which separated gamma rays from neutrons (n). Two long-duration flights were made with this detector in 1970 at Palestine, Tex. (P sub c = 4.6 Gv) and at Ft. Churchill, Canada (P sub c = 0.3 Gv).

  12. Long-term channel adjustment and geomorphic feature creation by vegetation in a lowland, low energy river

    NASA Astrophysics Data System (ADS)

    Grabowski, Robert; Gurnell, Angela

    2016-04-01

    Physical habitat restoration is increasingly being used to improve the ecological status of rivers. This is particularly true for lowland streams which are perceived to lack sufficient energy to create new features or to flush out fine sediment derived from agricultural and urban sources. However, this study has found that even in low-energy, base-flow dominated chalk streams, physical habitat improvement can happen naturally without direct human intervention. Furthermore this positive change is achieved by components of the river that are often regarded as management problems: in-stream macrophytes (i.e. weed), riparian trees, woody debris, and most importantly fine sediment. This project investigated the long-term changes in channel planform for the River Frome (Dorset, UK) over the last 120 years and the role of aquatic and riparian vegetation in driving this change. Agricultural census data, historical maps, recent aerial images and field observations were analysed within a process-based, hierarchical framework for hydromorphological assessment, developed in the EU FP7 REFORM project, to investigate the source and timing of fine sediment production in the catchment, to quantify the reach-scale geomorphic response, and to identify vegetation-related bedforms that could be responsible for the adjustment. The analysis reveals that the channel has narrowed and become more sinuous in the last 50-60 years. The timing of this planform adjustment correlates with substantial changes in land use and agricultural practices (post-World War II) that are known to increase soil erosion and sediment connectivity. The field observations and recent aerial images suggest that the increased delivery of fine sediment to the channel has been translated into geomorphic adjustment and diversification though the interactions between vegetation, water flow and sediment. Emergent aquatic macrophytes are retaining fine sediment, leading to the development of submerged shelves that aggrade

  13. Scenario analysis of carbon emissions' anti-driving effect on Qingdao's energy structure adjustment with an optimization model, Part II: Energy system planning and management.

    PubMed

    Wu, C B; Huang, G H; Liu, Z P; Zhen, J L; Yin, J G

    2017-03-01

    In this study, an inexact multistage stochastic mixed-integer programming (IMSMP) method was developed for supporting regional-scale energy system planning (EPS) associated with multiple uncertainties presented as discrete intervals, probability distributions and their combinations. An IMSMP-based energy system planning (IMSMP-ESP) model was formulated for Qingdao to demonstrate its applicability. Solutions which can provide optimal patterns of energy resources generation, conversion, transmission, allocation and facility capacity expansion schemes have been obtained. The results can help local decision makers generate cost-effective energy system management schemes and gain a comprehensive tradeoff between economic objectives and environmental requirements. Moreover, taking the CO2 emissions scenarios mentioned in Part I into consideration, the anti-driving effect of carbon emissions on energy structure adjustment was studied based on the developed model and scenario analysis. Several suggestions can be concluded from the results: (a) to ensure the smooth realization of low-carbon and sustainable development, appropriate price control and fiscal subsidy on high-cost energy resources should be considered by the decision-makers; (b) compared with coal, natural gas utilization should be strongly encouraged in order to insure that Qingdao could reach the carbon discharges peak value in 2020; (c) to guarantee Qingdao's power supply security in the future, the construction of new power plants should be emphasised instead of enhancing the transmission capacity of grid infrastructure.

  14. Evolution of and High-Energy Emission from GHz-Peaked Spectrum Sources

    NASA Astrophysics Data System (ADS)

    Stawarz, Ł.; Ostorero, L.; Begelman, M. C.; Moderski, R.; Kataoka, J.; Wagner, S.

    2008-06-01

    Here we discuss evolution and broadband emission of compact (energy losses, as well as radiative cooling. This allows us to discuss the broadband lobe emission of young radio sources. In particular, we argue that the observed spectral turnover in the radio synchrotron spectra of these objects cannot originate from the synchrotron self-absorption process but is most likely due to free-free absorption effects connected with neutral clouds of interstellar medium engulfed by the expanding lobes and photoionized by active centers. We also find a relatively strong and complex high-energy emission component produced by inverse Compton upscattering of various surrounding photon fields by the lobes' electrons. We argue that such high-energy radiation is strong enough to account for several observed properties of GHz-peaked spectrum (GPS) radio galaxies at UV and X-ray frequencies. In addition, this emission is expected to extend up to GeV (or possibly even TeV) photon energies and can thus be probed by several modern γ-ray instruments. In particular, we suggest that GPS radio galaxies should constitute a relatively numerous class of extragalactic sources detected by GLAST.

  15. On the Evolution of and High-Energy Emission from GHz-Peaked-Spectrum Sources

    SciTech Connect

    Stawarz, L.; Ostorero, L.; Begelman, M.C.; Moderski, R.; Kataoka, J.; Wagner, S.

    2007-12-18

    Here we discuss evolution and broad-band emission of compact (< kpc) lobes in young radio sources. We propose a simple dynamical description for these objects, consisting of a relativistic jet propagating into a uniform gaseous medium in the central parts of an elliptical host. In the framework of the proposed model, we follow the evolution of ultrarelativistic electrons injected from a terminal hotspot of a jet to expanding lobes, taking into account their adiabatic energy losses as well as radiative cooling. This allows us to discuss the broad-band lobe emission of young radio sources. In particular, we argue that the observed spectral turnover in the radio synchrotron spectra of these objects cannot originate from the synchrotron self-absorption process but is most likely due to free-free absorption effects connected with neutral clouds of interstellar medium engulfed by the expanding lobes and photoionized by active centers. We also find a relatively strong and complex high-energy emission component produced by inverse-Compton up-scattering of various surrounding photon fields by the lobes electrons. We argue that such high energy radiation is strong enough to account for several observed properties of GHz-peaked-spectrum (GPS) radio galaxies at UV and X-ray frequencies. In addition, this emission is expected to extend up to GeV (or possibly even TeV) photon energies and can thus be probed by several modern {gamma}-ray instruments. In particular, we suggest that GPS radio galaxies should constitute a relatively numerous class of extragalactic sources detected by GLAST.

  16. On the cross-helicity dependence of the energy spectrum in magnetohydrodynamic turbulence

    SciTech Connect

    Podesta, J. J.

    2011-01-15

    Phenomenological theories of strong incompressible magnetohydrodynamic (MHD) turbulence derived by Goldreich and Sridhar (GS) in 1995 and by Boldyrev in 2006 are only applicable to turbulence with vanishing cross-helicity. In this study, these two theories are generalized to treat turbulence with nonvanishing cross-helicity in such a way that the relation (w{sup +}/w{sup -}){sup 2}=({epsilon}{sup +}/{epsilon}{sup -}){sup 2} observed in numerical simulations is satisfied. The average energy (second order structure function) in the generalized GS theory is E(r{sub perpendicular})={phi}{sub 1}({sigma}{sub c})({epsilon}r{sub perpendicular}){sup 2/3} and that in the generalized Boldyrev theory is E(r{sub perpendicular})={phi}{sub 2}({sigma}{sub c})(v{sub A{epsilon}}r{sub perpendicular}){sup 1/2}, where the function {phi}({sigma}{sub c}) describes the dependence on the normalized cross-helicity {sigma}{sub c}. The form of the function {phi}({sigma}{sub c}) is derived through a renormalization of the variable {sigma}{sub c} that yields a one parameter family of solutions. The theory derived by Lithwick, Goldreich, and Sridhar (LGS) in 2007 is a special case of the generalized GS theory derived here; however, other generalizations of the GS theory are obtained that have a different cross-helicity dependence than the LGS theory. This new class of solutions and similar generalizations of Boldyrev's theory are investigated to see how the energy cascade rate {epsilon} changes as a function of {sigma}{sub c} when the energy at a given scale is held fixed. The generalization of Boldyrev's theory derived here is applicable to homogeneous MHD turbulence in the solar wind, for example, and can be used to obtain the turbulent dissipation rate {epsilon} from measurements of the energy spectrum and the normalized cross-helicity.

  17. Potential energy surface crossings and the mechanistic spectrum for intramolecular electron transfer in organic radical cations.

    PubMed

    Blancafort, L; Jolibois, F; Olivucci, M; Robb, M A

    2001-01-31

    The structure of the potential energy surface for the intramolecular electron transfer (IET) of four different model radical cations has been determined by using reaction path mapping and conical intersection optimization at the ab initio CASSCF level of theory. We show that, remarkably, the calculated paths reside in regions of the ground-state energy surface whose structure can be understood in terms of the position and properties of a surface crossing between the ground and the first excited state of the reactant. Thus, in the norbornadiene radical cation and in an analogue compound formed by two cyclopentene units linked by a norbornyl bridge, IET proceeds along direct-overlap and super-exchange concerted paths, respectively, that are located far from a sloped conical intersection point and in a region where the excited-state and ground-state surfaces are well separated. A second potential energy surface structure has been documented for 1,2-diamino ethane radical cation and features two parallel concerted (direct) and stepwise (chemical) paths. In this case a peaked conical intersection is located between the two paths. Finally, a third type of energy surface is documented for the bismethyleneadamantane radical cation and occurs when there is, effectively, a seam of intersection points (not a conical intersection) which separates the reactant and product regions. Since the reaction path cannot avoid the intersection, IET can only occur nonadiabatically. These IET paths indicate that quite different IET mechanisms may operate in radical cations, revealing an unexpectedly enriched and flexible mechanistic spectrum. We show that the origin of each path can be analyzed and understood in terms of the one-dimensional Marcus-Hush model.

  18. The Energy Spectrum of Atmospheric Neutrinos between 2 and 200 TeV with the AMANDA-II Detector

    SciTech Connect

    IceCube Collaboration; Abbasi, R.

    2010-05-11

    The muon and anti-muon neutrino energy spectrum is determined from 2000-2003 AMANDA telescope data using regularised unfolding. This is the first measurement of atmospheric neutrinos in the energy range 2-200 TeV. The result is compared to different atmospheric neutrino models and it is compatible with the atmospheric neutrinos from pion and kaon decays. No significant contribution from charm hadron decays or extraterrestrial neutrinos is detected. The capabilities to improve the measurement of the neutrino spectrum with the successor experiment IceCube are discussed.

  19. Spectrum bandwidth narrowing of Thomson scattering X-rays with energy chirped electron beams from laser wakefield acceleration

    SciTech Connect

    Xu, Tong; Chen, Min Li, Fei-Yu; Yu, Lu-Le; Sheng, Zheng-Ming; Zhang, Jie

    2014-01-06

    We study incoherent Thomson scattering between an ultrashort laser pulse and an electron beam accelerated from a laser wakefield. The energy chirp effects of the accelerated electron beam on the final radiation spectrum bandwidth are investigated. It is found that the scattered X-ray radiation has the minimum spectrum width and highest intensity as electrons are accelerated up to around the dephasing point. Furthermore, it is proposed that the electron acceleration process inside the wakefield can be studied by use of 90° Thomson scattering. The dephasing position and beam energy chirp can be deduced from the intensity and bandwidth of the scattered radiation.

  20. The energy spectrum of atmospheric neutrinos between 2 and 200 TeV with the AMANDA-II detector

    NASA Astrophysics Data System (ADS)

    Abbasi, R.; Abdou, Y.; Abu-Zayyad, T.; Adams, J.; Aguilar, J. A.; Ahlers, M.; Andeen, K.; Auffenberg, J.; Bai, X.; Baker, M.; Barwick, S. W.; Bay, R.; Bazo Alba, J. L.; Beattie, K.; Beatty, J. J.; Bechet, S.; Becker, J. K.; Becker, K.-H.; Benabderrahmane, M. L.; Berdermann, J.; Berghaus, P.; Berley, D.; Bernardini, E.; Bertrand, D.; Besson, D. Z.; Bissok, M.; Blaufuss, E.; Boersma, D. J.; Bohm, C.; Böser, S.; Botner, O.; Bradley, L.; Braun, J.; Buitink, S.; Carson, M.; Chirkin, D.; Christy, B.; Clem, J.; Clevermann, F.; Cohen, S.; Colnard, C.; Cowen, D. F.; D'Agostino, M. V.; Danninger, M.; De Clercq, C.; Demirörs, L.; Depaepe, O.; Descamps, F.; Desiati, P.; de Vries-Uiterweerd, G.; DeYoung, T.; Díaz-Vélez, J. C.; Dreyer, J.; Dumm, J. P.; Duvoort, M. R.; Ehrlich, R.; Eisch, J.; Ellsworth, R. W.; Engdegård, O.; Euler, S.; Evenson, P. A.; Fadiran, O.; Fazely, A. R.; Fedynitch, A.; Feusels, T.; Filimonov, K.; Finley, C.; Foerster, M. M.; Fox, B. D.; Franckowiak, A.; Franke, R.; Gaisser, T. K.; Gallagher, J.; Ganugapati, R.; Geisler, M.; Gerhardt, L.; Gladstone, L.; Glüsenkamp, T.; Goldschmidt, A.; Goodman, J. A.; Grant, D.; Griesel, T.; Groß, A.; Grullon, S.; Gunasingha, R. M.; Gurtner, M.; Ha, C.; Hallgren, A.; Halzen, F.; Han, K.; Hanson, K.; Helbing, K.; Herquet, P.; Hickford, S.; Hill, G. C.; Hoffman, K. D.; Homeier, A.; Hoshina, K.; Hubert, D.; Huelsnitz, W.; Hülß, J.-P.; Hulth, P. O.; Hultqvist, K.; Hussain, S.; Imlay, R. L.; Ishihara, A.; Jacobsen, J.; Japaridze, G. S.; Johansson, H.; Joseph, J. M.; Kampert, K.-H.; Kappes, A.; Karg, T.; Karle, A.; Kelley, J. L.; Kemming, N.; Kenny, P.; Kiryluk, J.; Kislat, F.; Klein, S. R.; Knops, S.; Köhne, J.-H.; Kohnen, G.; Kolanoski, H.; Köpke, L.; Koskinen, D. J.; Kowalski, M.; Kowarik, T.; Krasberg, M.; Krings, T.; Kroll, G.; Kuehn, K.; Kuwabara, T.; Labare, M.; Lafebre, S.; Laihem, K.; Landsman, H.; Lauer, R.; Lehmann, R.; Lennarz, D.; Lünemann, J.; Madsen, J.; Majumdar, P.; Maruyama, R.; Mase, K.; Matis, H. S.; Matusik, M.; Meagher, K.; Merck, M.; Mészáros, P.; Meures, T.; Middell, E.; Milke, N.; Montaruli, T.; Morse, R.; Movit, S. M.; Münich, K.; Nahnhauer, R.; Nam, J. W.; Naumann, U.; Nießen, P.; Nygren, D. R.; Odrowski, S.; Olivas, A.; Olivo, M.; Ono, M.; Panknin, S.; Paul, L.; Pérez de los Heros, C.; Petrovic, J.; Piegsa, A.; Pieloth, D.; Porrata, R.; Posselt, J.; Price, P. B.; Prikockis, M.; Przybylski, G. T.; Rawlins, K.; Redl, P.; Resconi, E.; Rhode, W.; Ribordy, M.; Rizzo, A.; Rodrigues, J. P.; Roth, P.; Rothmaier, F.; Rott, C.; Roucelle, C.; Ruhe, T.; Rutledge, D.; Ruzybayev, B.; Ryckbosch, D.; Sander, H.-G.; Sarkar, S.; Schatto, K.; Schlenstedt, S.; Schmidt, T.; Schneider, D.; Schukraft, A.; Schultes, A.; Schulz, O.; Schunck, M.; Seckel, D.; Semburg, B.; Seo, S. H.; Sestayo, Y.; Seunarine, S.; Silvestri, A.; Slipak, A.; Spiczak, G. M.; Spiering, C.; Stamatikos, M.; Stanev, T.; Stephens, G.; Stezelberger, T.; Stokstad, R. G.; Stoyanov, S.; Strahler, E. A.; Straszheim, T.; Sullivan, G. W.; Swillens, Q.; Taboada, I.; Tamburro, A.; Tarasova, O.; Tepe, A.; Ter-Antonyan, S.; Tilav, S.; Toale, P. A.; Tosi, D.; Turčan, D.; van Eijndhoven, N.; Vandenbroucke, J.; Van Overloop, A.; van Santen, J.; Voigt, B.; Walck, C.; Waldenmaier, T.; Wallraff, M.; Walter, M.; Wendt, C.; Westerhoff, S.; Whitehorn, N.; Wiebe, K.; Wiebusch, C. H.; Wikström, G.; Williams, D. R.; Wischnewski, R.; Wissing, H.; Woschnagg, K.; Xu, C.; Xu, X. W.; Yodh, G.; Yoshida, S.; Zarzhitsky, P.

    2010-08-01

    The muon and anti-muon neutrino energy spectrum is determined from 2000-2003 AMANDA telescope data using regularised unfolding. This is the first measurement of atmospheric neutrinos in the energy range 2-200 TeV. The result is compared to different atmospheric neutrino models and it is compatible with the atmospheric neutrinos from pion and kaon decays. No significant contribution from charm hadron decays or extraterrestrial neutrinos is detected. The capabilities to improve the measurement of the neutrino spectrum with the successor experiment IceCube are discussed.

  1. The Energy Spectrum of Energetic Particles Downstream of Turbulent Collisionless Shocks

    NASA Astrophysics Data System (ADS)

    Giacalone, Joe; Neugebauer, Marcia

    2008-01-01

    Using simple analytic considerations, numerical simulations, and data analysis, we discuss the physics of charged-particle acceleration by turbulent, rippled, collisionless shocks. The standard theory of diffusive shock acceleration predicts that the energetic-particle energy spectrum, in the region of shocked plasma, is a function of the plasma density jump. But because of the interaction of the shock with plasma turbulence, the jump in plasma density varies in time and from place to place on the shock front. Here we show that for reasonable parameters, the shape of the energetic-particle energy spectra downstream of any given shock is nearly independent of location along the shock front, even though the density jump varies. This is because energetic particles are mobile and sample many turbulent fluctuations during their acceleration. This result holds for shocks having smaller scale ripples than the large-scale radius of curvature (Dc) of the shock. Thus, it applies to the interpretation of spacecraft observations of traveling interplanetary shocks provided the spacecraft separation is less than Dc. This result is confirmed with simple analytic considerations and numerical simulations that solve the combined magnetohydrodynamic equations for a plasma and energetic test particles using the well-known Parker transport equation. This conclusion is further supported by our analysis of ACE and Geotail observations of a few interplanetary shocks.

  2. Energy spectrum in high-resolution direct numerical simulations of turbulence

    NASA Astrophysics Data System (ADS)

    Ishihara, Takashi; Morishita, Koji; Yokokawa, Mitsuo; Uno, Atsuya; Kaneda, Yukio

    2016-12-01

    A study is made about the energy spectrum E (k ) of turbulence on the basis of high-resolution direct numerical simulations (DNSs) of forced incompressible turbulence in a periodic box using a Fourier spectral method with the number of grid points and the Taylor scale Reynolds number Rλ up to 12 2883 and approximately 2300, respectively. The DNS data show that there is a wave-number range (approximately 5 ×10-3 2 /3k-5 /3] =c (kL ) m , where <ɛ > is the mean energy dissipation rate per unit mass; L is the integral length scale; and m ≈-0.12 . The coefficient c is independent of k , but has a Rλ dependence, such as c =C Rλζ , where C ≈0.9 and ζ ≈0.14 .

  3. Nonlinear optical conductivity resulting from the local energy spectrum at the M point in graphene

    NASA Astrophysics Data System (ADS)

    Liu, Zheng; Zhang, Chao; Cao, J. C.

    2017-07-01

    Based on the tight-binding model we construct a nonlinear Hamiltonian to describe the effective electric system around the M point for the single layer graphene. The local energy spectrum at the M point is approximated by the perfect hyperbolic geometry, and the modification by the screening effect from the substrate is taken into account. With the method based on the concept of the Floquet states and quasienergies (FSQ) we investigate the third order nonlinear conductivity σ3(ω ) ,σ3(3 ω ) for the different frequency ranges, respectively, in which only the π -π* bands are involved. A positive cusplike peak arises at ℏ ω =ɛgap(M) /3 for σ3(3 ω ) which originates from the three-photon processes. Also, there is a peak at ɛgap(M) /2 for σ3(ω ) resulting from two-photon-resonant processes. The analysis of the pole processes indicates that a self-energy-like term transition process plays a role in the nonlinear optical response, and the different transition processes interact with each other during the response to the external field. These interactions can be influenced by the polarization of the external field.

  4. Obscured flat spectrum radio active galactic nuclei as sources of high-energy neutrinos

    NASA Astrophysics Data System (ADS)

    Maggi, G.; Buitink, S.; Correa, P.; de Vries, K. D.; Gentile, G.; Tavares, J. León; Scholten, O.; van Eijndhoven, N.; Vereecken, M.; Winchen, T.

    2016-11-01

    Active galactic nuclei (AGN) are believed to be one of the main source candidates for the high-energy (TeV-PeV) cosmic neutrino flux recently discovered by the IceCube neutrino observatory. Nevertheless, several correlation studies between AGN and the cosmic neutrinos detected by IceCube show no significance. Therefore, in this article we consider a specific subclass of AGN for which an increased neutrino production is expected. This subclass contains AGN for which their high-energy jet is pointing toward Earth. Furthermore, we impose the condition that the jet is obscured by gas or dust surrounding the AGN. A method is presented to determine the total column density of the obscuring medium, which is probed by determining the relative x-ray attenuation with respect to the radio flux as obtained from the AGN spectrum. The total column density allows us to probe the interaction of the jet with the surrounding matter, which leads to additional neutrino production. Finally, starting from two different source catalogs, this method is applied to specify a sample of low redshift radio galaxies for which an increased neutrino production is expected.

  5. The Spectrum of Thorium from 250 nm to 5500 nm: Ritz Wavelengths and Optimized Energy Levels

    NASA Astrophysics Data System (ADS)

    Redman, Stephen L.; Nave, Gillian; Sansonetti, Craig J.

    2014-03-01

    We have made precise observations of a thorium-argon hollow cathode lamp emission spectrum in the region between 350 nm and 1175 nm using a high-resolution Fourier transform spectrometer. Our measurements are combined with results from seven previously published thorium line lists to re-optimize the energy levels of neutral, singly, and doubly ionized thorium (Th I, Th II, and Th III). Using the optimized level values, we calculate accurate Ritz wavelengths for 19, 874 thorium lines between 250 nm and 5500 nm (40, 000 cm-1 to 1800 cm-1). We have also found 102 new thorium energy levels. A systematic analysis of previous measurements in light of our new results allows us to identify and propose corrections for systematic errors in Palmer & Engleman and typographical errors and incorrect classifications in Kerber et al. We also found a large scatter with respect to the thorium line list of Lovis & Pepe. We anticipate that our Ritz wavelengths will lead to improved measurement accuracy for current and future spectrographs that make use of thorium-argon or thorium-neon lamps as calibration standards.

  6. Estimation of a photon energy spectrum for a computed tomography scanner.

    PubMed

    Ruth, C; Joseph, P M

    1997-05-01

    Estimated photon energy spectra are derived from transmission measurements using aluminium, copper, and sodium iodide absorbers. Two spectral models are proposed. One is based on a previously published model that analyzes the electron's penetration into the anode, and the production and attenuation of bremsstrahlung photons. The second model does not include details regarding the underlying physics, but treats the spectrum as a sum of delta functions. A nonlinear regularization method is used to overcome ill conditioning in the second model. Both models fit the transmission data to an accuracy of 0.30%, which is consistent with the experimental error. A quantitative comparison of the models is made by calculating the average and variance (over the derived energy spectra) of several relevant mass attenuation coefficients. The maximum variation in the average and variance was 1.5% and 3.2%, respectively, indicating that the spectra exhibit similar attenuation and beam hardening properties. The spectra were tested with a simulation that predicts scanner CT numbers for phantom measurements consisting of dilutions of sodium iodide in a water equivalent background. The agreement between simulation and experiment ranged from 1.5% at 220 HU to 4.4% at 1700 HU.

  7. Probe measurements of electron energy spectrum in Helium/air micro-plasma at atmospheric pressure

    NASA Astrophysics Data System (ADS)

    Demidov, V. I.; Adams, S. F.; Miles, J. A.; Koepke, M. E.; Kurlyandskaya, I. P.; Hensley, A. L.; Tolson, B. A.

    2016-09-01

    It is experimentally demonstrated that a wall probe may be a useful instrument for interpretation of electron energy spectrum in a micro-plasma with a nonlocal electron distribution function at atmospheric pressure. Two micro-plasma devices were fabricated with three layers of molybdenum metal foils with thickness of 0.1 mm separated by two sheets of mica insulation with thickness of 0.11 mm. In one device a hole with the diameter of 0.2 mm formed a cylindrical discharge cavity that passed through the entire five layers. In the second device the hole has the diameter of 0.065 mm. In both devices the inner molybdenum layer formed a wall probe, while the outer layers of molybdenum served as the hollow cathode and anode. The discharge was open into air with flow of helium gas. It is found that the wall probe I-V trace is sensitive to the presence of helium metastable atoms. The first derivative of the probe current with respect to the probe potential shows peaks revealing fast electrons at specific energies arising due to plasma chemical reactions. The devices may be applicable for developing analytical sensors for extreme environments, including high radiation and vibration levels and high temperatures. This work was performed while VID held a NRC Research Associateship Award at AFRL.

  8. THE SPECTRUM OF THORIUM FROM 250 nm TO 5500 nm: RITZ WAVELENGTHS AND OPTIMIZED ENERGY LEVELS

    SciTech Connect

    Redman, Stephen L.; Nave, Gillian; Sansonetti, Craig J.

    2014-03-01

    We have made precise observations of a thorium-argon hollow cathode lamp emission spectrum in the region between 350 nm and 1175 nm using a high-resolution Fourier transform spectrometer. Our measurements are combined with results from seven previously published thorium line lists to re-optimize the energy levels of neutral, singly, and doubly ionized thorium (Th I, Th II, and Th III). Using the optimized level values, we calculate accurate Ritz wavelengths for 19, 874 thorium lines between 250 nm and 5500 nm (40, 000 cm{sup –1} to 1800 cm{sup –1}). We have also found 102 new thorium energy levels. A systematic analysis of previous measurements in light of our new results allows us to identify and propose corrections for systematic errors in Palmer and Engleman and typographical errors and incorrect classifications in Kerber et al. We also found a large scatter with respect to the thorium line list of Lovis and Pepe. We anticipate that our Ritz wavelengths will lead to improved measurement accuracy for current and future spectrographs that make use of thorium-argon or thorium-neon lamps as calibration standards.

  9. Spectrum and anisotropy of cosmic rays at TeV-PeV-energies and contribution of nearby sources

    NASA Astrophysics Data System (ADS)

    Sveshnikova, L. G.; Strelnikova, O. N.; Ptuskin, V. S.

    2013-12-01

    The role of nearby galactic sources, the supernova remnants, in formation of observed energy spectrum and large-scale anisotropy of high-energy cosmic rays is studied. The list of these sources is made up based on radio, X-ray and gamma-ray catalogues. The distant sources are treated statistically as ensemble of sources with random positions and ages. The source spectra are defined based on the modern theory of cosmic ray acceleration in supernova remnants while the propagation of cosmic rays in the interstellar medium is described in the frameworks of galactic diffusion model. Calculations of dipole component of anisotropy are made to reproduce the experimental procedure of "two-dimensional" anisotropy measurements. The energy dependence of particle escape time in the process of acceleration in supernova remnants and the arm structure of sources defining the significant features of anisotropy are also taken into account. The essential new trait of the model is a decreasing number of core collapse SNRs being able to accelerate cosmic rays up to the given energy, that leads to steeper total cosmic ray source spectrum in comparison with the individual source spectrum. We explained simultaneously the new cosmic ray data on the fine structure of all particle spectrum around the knee and the amplitude and direction of the dipole component of anisotropy in the wide energy range 1 TeV-1 EeV. Suggested assumptions do not look exotic, and they confirm the modern understanding of cosmic ray origin.

  10. Valence band energy spectrum of HgTe quantum wells with an inverted band structure

    NASA Astrophysics Data System (ADS)

    Minkov, G. M.; Aleshkin, V. Ya.; Rut, O. E.; Sherstobitov, A. A.; Germanenko, A. V.; Dvoretski, S. A.; Mikhailov, N. N.

    2017-07-01

    The energy spectrum of the valence band in HgTe /CdxHg1 -xTe quantum wells of a width (8 -20 ) nm has been studied experimentally by magnetotransport effects and theoretically in the framework of a four-band k P method. Comparison of the Hall density with the density found from a period of the Shubnikov-de Haas (SdH) oscillations clearly shows that the degeneracy of states of the top of the valence band is equal to 2 at the hole density p <5.5 ×1011cm-2 . Such degeneracy does not agree with the calculations of the spectrum performed within the framework of the four-band k P method for symmetric quantum wells. These calculations show that the top of the valence band consists of four spin-degenerate extremes located at k ≠0 (valleys) which gives the total degeneracy K =8 . It is shown that taking into account the "mixing of states" at the interfaces leads to the removal of the spin degeneracy that reduces the degeneracy to K =4 . Accounting for any additional asymmetry, for example, due to the difference in the mixing parameters at the interfaces, the different broadening of the boundaries of the well, etc., leads to reduction of the valleys degeneracy, making K =2 . It is noteworthy that for our case twofold degeneracy occurs due to degeneracy of two single-spin valleys. The hole effective mass (mh) determined from analysis of the temperature dependence of the amplitude of the SdH oscillations shows that mh is equal to (0.25 ±0.02 ) m0 and weakly increases with the hole density. Such a value of mh and its dependence on the hole density are in a good agreement with the calculated effective mass.

  11. Spallation Neutron Energy Spectrum Determination with Yttrium as a Threshold Detector on U/Pb-assembly ``Energy plus Transmutation''

    NASA Astrophysics Data System (ADS)

    Kilim, S.; Bielewicz, M.; Strugalska-Gola, E.; Szuta, M.; Wojciechowski, A.; Krivopustov, M. I.; Kovalenko, A. D.; Adam, I.; Krasa, A.; Majerle, M.; Wagner, V.

    Results of two experiments with Yttrium-89 samples on U/Pb-assembly “Energy plus Transmutation” [1] are presented. The assembly is a lead cylindrical target (8.4 cm diameter, 45.6 cm length) with natural uranium blanket (206.4 kg). The lead target was irradiated with JINR Dubna NUCLOTRON with 1.60 and 2.52 GeV deuteron beam. The final purpose of the experiments was to measure neutron field inside the assembly. Yttrium-89 activation detectors were located throughout the entire U/Pb-assembly. Irradiated sample gamma activity was measured with HPGe spectrometer. The gamma spectra were analyzed and the net peak areas were calculated using the DEIMOS program [2]. After short presentation of the activation results neutron spectrum determination method is proposed and its results presented. Assuming reaction model through compound nucleus and using some mathematical tricks Yttrium isotope “k ” production rate discrete formula I_k = Nintlimits_{E_{thr,k} }^infty {φ left( E right)σ _k left( {E,E_{thr} } right)} dE was transformed into Volterra's integral equation of the first kind and then solved. The method and its applicability still to be discussed. The results as the preliminary ones are for illustrative purpose only.

  12. Spallation Neutron Energy Spectrum Determination with Yttrium as a Threshold Detector on U/Pb-assembly "Energy plus Transmutation"

    NASA Astrophysics Data System (ADS)

    Kilim, S.; Bielewicz, M.; Strugalska-Gola, E.; Szuta, M.; Wojciechowski, A.; Krivopustov, M. I.; Kovalenko, A. D.; Adam, I.; Krasa, A.; Majerle, M.; Wagner, V.

    Results of two experiments with Yttrium-89 samples on U/Pb-assembly "Energy plus Transmutation" [1] are presented. The assembly is a lead cylindrical target (8.4 cm diameter, 45.6 cm length) with natural uranium blanket (206.4 kg). The lead target was irradiated with JINR Dubna NUCLOTRON with 1.60 and 2.52 GeV deuteron beam. The final purpose of the experiments was to measure neutron field inside the assembly. Yttrium-89 activation detectors were located throughout the entire U/Pb-assembly. Irradiated sample gamma activity was measured with HPGe spectrometer. The gamma spectra were analyzed and the net peak areas were calculated using the DEIMOS program [2]. After short presentation of the activation results neutron spectrum determination method is proposed and its results presented. Assuming reaction model through compound nucleus and using some mathematical tricks Yttrium isotope "k " production rate discrete formula I_k = Nintlimits_{E_{thr,k} }^infty {φ left( E right)σ _k left( {E,E_{thr} } right)} dE was transformed into Volterra's integral equation of the first kind and then solved. The method and its applicability still to be discussed. The results as the preliminary ones are for illustrative purpose only.

  13. Variations in energy metabolism along the pericardium meridian and its relationship with visceral function adjustments during electroacupuncture.

    PubMed

    Zheng, Shu-Xia; Pan, Xiao-Hua; Xu, Jin-Sen; Xiu, Chun-Ying; Dong, Ya-Qin; Zhu, Xiaoxiang

    2014-08-30

    Electroacupuncture (EA) is a traditional Chinese medicine treatment guided by meridian theory. As it gradually gains more worldwide acceptance, a clarification of its mechanisms is extremely urgent. We observed variations in transcutaneous oxygen pressure/carbon dioxide pressure (tcpO2/tcpCO2) and microcirculation blood perfusion units (BPU) along the pericardium meridian, and cardiac function during EA at Neiguan (PC6) to explore variations in energy metabolism and its relationship with visceral function adjustments during EA. Twenty-two healthy volunteers participated in this study. Three channel laser Doppler flowmetry and tcpO2/tcpCO2 detection systems were used to detect tcpO2/tcpCO2 and microcirculation BPU along the pericardium meridian. A hemodynamic monitor was used to detect cardiac function. In the normal state, the microcirculatory BPU along the pericardium meridian were significantly higher than that of their bilateral corresponding control points (p < 0.05). During EA at PC6, the values of the microcirculatory BPU along the pericardium meridian did not vary, and few increased. In the normal state, the values of tcpO2 along the pericardium meridian were significantly higher than those of their bilateral corresponding control points (p < 0.05). In addition, the values of tcpCO2 along the pericardium meridian were lower than those of their bilateral corresponding control points. In comparison with the normal state, EA could decrease tcpO2 along the meridian significantly (p < 0.05) and increase tcpCO2. During EA at PC6 in healthy volunteers treated by artificial acute mild hypoxia, cardiac output and cardiac index (p < 0.05) decreased and systemic vascular resistance increased significantly (p < 0.05). In the normal state, the values of microcirculatory BPU and tcpO2 along the pericardium meridian were both higher than those of their bilateral corresponding control points. Energy metabolism was vigorous along the meridian. During EA

  14. The sup 252 Cf(sf) neutron spectrum in the 5- to 20-MeV energy range

    SciTech Connect

    Marten, H.; Richter, D.; Seeliger, D. ); Fromm, W.D. ); Bottger, R.; Klein, H. )

    1990-11-01

    This paper reports on the {sup 252}Cf neutron spectrum measured at high energies with a miniature ionization chamber and two different NE-213 neutron detectors. The gamma-ray background and the main cosmic background caused by muons were suppressed by applying efficient pulse-shape discrimination. On the basis of two-dimensional spectroscopy of the neutron time-of-flight and scintillation pulse height, the sliding bias method is used to minimize experimental uncertainties. The experimental data, corrected for several systematic influences, confirm earlier results that show negative deviations from a reference Maxwellian distribution with a 1.42-MeV spectrum temperature for neutron energies above 6 MeV. Experimental results of this work are compared with various statistical model approaches to the {sup 252}Cf(sf) neutron spectrum.

  15. Magnetotransport in double quantum well with inverted energy spectrum: HgTe/CdHgTe

    NASA Astrophysics Data System (ADS)

    Yakunin, M. V.; Suslov, A. V.; Popov, M. R.; Novik, E. G.; Dvoretsky, S. A.; Mikhailov, N. N.

    2016-02-01

    We present an experimental study of the double-quantum-well (DQW) system made of two-dimensional layers with inverted energy band spectrum: HgTe. The magnetotransport reveals a considerably larger overlap of the conduction and valence subbands than in known HgTe single quantum wells (QW), which may be regulated here by an applied gate voltage Vg. This large overlap manifests itself in a much higher critical field Bc separating the range above it with a plain behavior of the Hall magnetoresistance ρx y(B ) , where the quantum peculiarities shift linearly with Vg, and the range below with a complicated behavior. In the latter case, specific structures in ρx y(B ) are formed like a double-N -shaped ρx y(B ) , reentrant sign-alternating quantum Hall effect with transitions into a zero-filling-factor state, etc., which are clearly manifested here due to better magnetic quantization at high fields, as compared to the features seen earlier in a single HgTe QW. The coexisting electrons and holes were found in the whole investigated range of positive and negative Vg as revealed (i) from fits to the low-field N -shaped ρx y(B ) , (ii) from the Fourier analysis of oscillations in ρx x(B ) , and (iii) from a specific behavior of ρx y(B ) at high positive Vg. A peculiar feature here is that the found electron density n remains almost constant in the whole range of investigated Vg while the hole density p drops down from the value a factor of 6 larger than n at extreme negative Vg to almost zero at extreme positive Vg passing through the charge-neutrality point. We show that this difference between n and p stems from an order of magnitude larger density of states for holes in the lateral valence subband maxima than for electrons in the conduction subband minimum. We analyze our observations on the basis of a calculated picture of magnetic levels in a DQW and suggest that their specificity is due to (i) a nonmonotonic course of the valence subband magnetic levels and an

  16. Energy spectrum of cosmic protons and helium nuclei by a hybrid measurement at 4300 m a.s.l.

    NASA Astrophysics Data System (ADS)

    Bartoli, B.; Bernardini, P.; J. Bi, X.; Bolognino, I.; Branchini, P.; Budano, A.; K. Calabrese Melcarne, A.; Camarri, P.; Cao, Z.; Cardarelli, R.; Catalanotti, S.; Z. Chen, S.; L. Chen, T.; Creti, P.; W. Cui, S.; Z. Dai, B.; D'Amone, A.; Danzengluobu; I. De, Mitri; B. D'Ettorre, Piazzoli; T. Di, Girolamo; G. Di, Sciascio; F. Feng, C.; Zhaoyang, Feng; Zhenyong, Feng; B. Gou, Q.; Q. Guo, Y.; H. He, H.; Haibing, Hu; Hongbo, Hu; Iacovacci, M.; Iuppa, R.; Y. Jia, H.; Labaciren; J. Li, H.; Liguori, G.; C., Liu; J., Liu; Y. Liu, M.; H., Lu; L. Ma, L.; H. Ma, X.; Mancarella, G.; M. Mari, S.; Marsella, G.; Martello, D.; Mastroianni, S.; Montini, P.; C. Ning, C.; Panareo, M.; Panico, B.; Perrone, L.; Pistilli, P.; Ruggieri, F.; Salvini, P.; Santonico, R.; N. Sbano, S.; R. Shen, P.; D. Sheng, X.; Shi, F.; Surdo, A.; H. Tan, Y.; Vallania, P.; Vernetto, S.; Vigorito, C.; H., Wang; Y. Wu, C.; R. Wu, H.; Xue, L.; Y. Yang, Q.; C. Yang, X.; G. Yao, Z.; F. Yuan, A.; Zha, M.; M. Zhang, H.; Zhang, L.; Y. Zhang, X.; Zhang, Y.; Zhao, J.; Zhaxiciren; Zhaxisangzhu; X. Zhou, X.; R. Zhu, F.; Q. Zhu, Q.; Zizzi, G.; X. Bai, Y.; J. Chen, M.; Y., Chen; H. Feng, S.; Gao, B.; H. Gu, M.; Hou, C.; X. Li, X.; J., Liu; L. Liu, J.; X., Wang; Xiao, G.; K. Zhang, B.; S. Zhang, S.; B., Zhou; Zuo, X.

    2014-04-01

    The energy spectrum of cosmic Hydrogen and Helium nuclei has been measured below the so-called “knee” by using a hybrid experiment with a wide field-of-view Cherenkov telescope and the Resistive Plate Chamber (RPC) array of the ARGO-YBJ experiment at 4300 m above sea level. The Hydrogen and Helium nuclei have been well separated from other cosmic ray components by using a multi-parameter technique. A highly uniform energy resolution of about 25% is achieved throughout the whole energy range (100-700 TeV). The observed energy spectrum is compatible with a single power law with index γ=-2.63±0.06.

  17. Balloon measurements of the energy spectrum of cosmic electrons between 1 GeV and 25 GeV

    NASA Technical Reports Server (NTRS)

    Earl, J. A.; Neely, D. E.; Rygg, T. A.

    1971-01-01

    During three balloon flights made in 1966 and 1967, cosmic electrons were investigated with the aid of a hodoscope detector which provided extensive and detailed information on each cosmic ray event triggering the apparatus. Similar information obtained during calibration exposures to protons and pions as well as to electrons was used to provide identification of cosmic electrons and to determine their energies. Differential primary electron intensities measured in the range from 1 GeV to 25 GeV were substantially larger than some earlier measurements. Taken in conjunction with existing measurements at energies above 100 GeV, this indicates that the energy spectrum of cosmic electrons is steeper than that of cosmic-ray nuclei and, consequently, suggests that Compton/synchrotron energy loss plays a significant role in shaping the electron spectrum.

  18. Multiconfiguration Dirac-Hartree-Fock Adjusted Energy-Consistent Pseudopotential for Uranium: Spin-Orbit Configuration Interaction and Fock-Space Coupled-Cluster Study of U4+ and U5+

    NASA Astrophysics Data System (ADS)

    Weigand, Anna; Cao, Xiaoyan; Vallet, Valérie; Flament, Jean-Pierre; Dolg, Michael

    2009-07-01

    In order to assess the accuracy of a recently adjusted relativistic energy-consistent small-core pseudopotential for uranium, the U5+ (5f1 subconfiguration) spin-orbit splitting as well as the fine structure of the U4+ (5f2 subconfiguration) spectrum have been calculated. The pseudopotential has been adjusted to four-component all-electron data, i.e., at the multiconfiguration Dirac-Hartree-Fock level using the Dirac-Coulomb Hamiltonian with a Fermi nucleus charge distribution and perturbatively including the Breit interaction. Its performance in a dressed effective Hamiltonian spin-orbit configuration interaction framework is compared to that of an older scalar-relativistic Wood-Boring adjusted pseudopotential, supplemented by a valence spin-orbit term, as well as to all-electron calculations using the Douglas-Kroll-Hess Hamiltonian. Electron correlation is accounted for by the multireference configuration interaction method with and without the Davidson correction and with different frozen-orbital spaces. Our best calculations show satisfactory agreement with experimental data; i.e., the mean absolute (relative) deviations amount to 183 (2.4%) and 948 cm-1 (5.1%) for the U5+ and the U4+ fine-structure energy levels, respectively. Even better agreement, comparable to the one for rigorous highly correlated four-component all-electron data, is obtained in intermediate Hamiltonian Fock-space coupled-cluster calculations applying the new pseudopotential.

  19. On the effect of an error in a standard D2O-moderated 252Cf energy spectrum.

    PubMed

    Cummings, F M

    2009-12-01

    There appears to be an error in the neutron fluence for neutrons with energies between 9 and 10 MeV for the tabulated D2O-moderated Cf source in ISO 8529-1. If the referenced spectrum is used as tabulated, the error contributes a total error to neutron dose values from this source of approximately 3%.

  20. Energy Spectrum of the Recurrent Variation of Galactic Cosmic Rays During the Solar Minimum of Cycles 23/24

    NASA Astrophysics Data System (ADS)

    Gil, Agnieszka; Alania, Michael V.

    2016-08-01

    The Sun during the recent epoch of solar activity operated in a different way than during the last 60 years, being less active. We study temporal changes of the energy spectrum of the first three harmonics of the 27-day variation of the galactic cosmic rays (GCR) intensity during the unusual, recent solar minimum, between Solar Cycles 23 and 24 (SC 23/24) and compare with four previous minima. We show that the energy spectrum of the amplitudes of the recurrent variation of the GCR intensity is hard in the maximum epochs and is soft in the minimum epochs during Solar Cycles 20 - 24, but with peculiarities during the Solar Minimum 23/24. In particular, while the energy/rigidity spectrum of the amplitudes of the first harmonic of the recurrent variation of the GCR intensity behaves practically the same as for previous epochs, the energy/rigidity spectrum of the amplitudes of the second and the third harmonics demonstrates a pronounced softening. We attribute this phenomenon to the decrease of the extension of the heliosphere caused by the decrease of the solar-wind dynamic pressure during the unusual Solar Minimum 23/24.

  1. Measurement of the Crab Nebula spectrum over three decades in energy with the MAGIC telescopes

    NASA Astrophysics Data System (ADS)

    Aleksić, J.; Ansoldi, S.; Antonelli, L. A.; Antoranz, P.; Babic, A.; Bangale, P.; Barrio, J. A.; Becerra González, J.; Bednarek, W.; Bernardini, E.; Biasuzzi, B.; Biland, A.; Blanch, O.; Bonnefoy, S.; Bonnoli, G.; Borracci, F.; Bretz, T.; Carmona, E.; Carosi, A.; Colin, P.; Colombo, E.; Contreras, J. L.; Cortina, J.; Covino, S.; Da Vela, P.; Dazzi, F.; De Angelis, A.; De Caneva, G.; De Lotto, B.; de Oña Wilhelmi, E.; Delgado Mendez, C.; Doert, M.; Dominis Prester, D.; Dorner, D.; Doro, M.; Einecke, S.; Eisenacher, D.; Elsaesser, D.; Fonseca, M. V.; Font, L.; Frantzen, K.; Fruck, C.; Galindo, D.; García López, R. J.; Garczarczyk, M.; Garrido Terrats, D.; Gaug, M.; Godinović, N.; González Muñoz, A.; Gozzini, S. R.; Hadasch, D.; Hanabata, Y.; Hayashida, M.; Herrera, J.; Hildebrand, D.; Hose, J.; Hrupec, D.; Idec, W.; Kadenius, V.; Kellermann, H.; Kodani, K.; Konno, Y.; Krause, J.; Kubo, H.; Kushida, J.; La Barbera, A.; Lelas, D.; Lewandowska, N.; Lindfors, E.; Lombardi, S.; López, M.; López-Coto, R.; López-Oramas, A.; Lorenz, E.; Lozano, I.; Makariev, M.; Mallot, K.; Maneva, G.; Mankuzhiyil, N.; Mannheim, K.; Maraschi, L.; Marcote, B.; Mariotti, M.; Martínez, M.; Mazin, D.; Menzel, U.; Miranda, J. M.; Mirzoyan, R.; Moralejo, A.; Munar-Adrover, P.; Nakajima, D.; Niedzwiecki, A.; Nilsson, K.; Nishijima, K.; Noda, K.; Nowak, N.; Orito, R.; Overkemping, A.; Paiano, S.; Palatiello, M.; Paneque, D.; Paoletti, R.; Paredes, J. M.; Paredes-Fortuny, X.; Persic, M.; Prada Moroni, P. G.; Prandini, E.; Preziuso, S.; Puljak, I.; Reinthal, R.; Rhode, W.; Ribó, M.; Rico, J.; Rodriguez Garcia, J.; Rügamer, S.; Saggion, A.; Saito, T.; Saito, K.; Satalecka, K.; Scalzotto, V.; Scapin, V.; Schultz, C.; Schweizer, T.; Shore, S. N.; Sillanpää, A.; Sitarek, J.; Snidaric, I.; Sobczynska, D.; Spanier, F.; Stamatescu, V.; Stamerra, A.; Steinbring, T.; Storz, J.; Strzys, M.; Takalo, L.; Takami, H.; Tavecchio, F.; Temnikov, P.; Terzić, T.; Tescaro, D.; Teshima, M.; Thaele, J.; Tibolla, O.; Torres, D. F.; Toyama, T.; Treves, A.; Uellenbeck, M.; Vogler, P.; Wagner, R. M.; Zanin, R.; Horns, D.; Martín, J.; Meyer, M.

    2015-03-01

    The MAGIC stereoscopic system collected 69 hours of Crab Nebula data between October 2009 and April 2011. Analysis of this data sample using the latest improvements in the MAGIC stereoscopic software provided an unprecedented precision of spectral and night-by-night light curve determination at gamma rays. We derived a differential spectrum with a single instrument from 50 GeV up to almost 30 TeV with 5 bins per energy decade. At low energies, MAGIC results, combined with Fermi-LAT data, show a flat and broad Inverse Compton peak. The overall fit to the data between 1 GeV and 30 TeV is not well described by a log-parabola function. We find that a modified log-parabola function with an exponent of 2.5 instead of 2 provides a good description of the data (χred2 = 35 / 26). Using systematic uncertainties of the MAGIC and Fermi-LAT measurements we determine the position of the Inverse Compton peak to be at (53 ±3stat +31syst -13syst) GeV, which is the most precise estimation up to date and is dominated by the systematic effects. There is no hint of the integral flux variability on daily scales at energies above 300 GeV when systematic uncertainties are included in the flux measurement. We consider three state-of-the-art theoretical models to describe the overall spectral energy distribution of the Crab Nebula. The constant B-field model cannot satisfactorily reproduce the VHE spectral measurements presented in this work, having particular difficulty reproducing the broadness of the observed IC peak. Most probably this implies that the assumption of the homogeneity of the magnetic field inside the nebula is incorrect. On the other hand, the time-dependent 1D spectral model provides a good fit of the new VHE results when considering a 80 μG magnetic field. However, it fails to match the data when including the morphology of the nebula at lower wavelengths.

  2. Weibull thermodynamics: Subexponential decay in the energy spectrum of cosmic-ray nuclei

    NASA Astrophysics Data System (ADS)

    Tomaschitz, Roman

    2017-10-01

    The spectral number density of cosmic-ray nuclei is shown to be a multiply broken power law with subexponential spectral cutoff. To this end, a spectral fit is performed to data sets covering the 1GeV - 1011GeV interval of the all-particle cosmic-ray spectrum. The flux points of the ultra-high energy spectral tail measured with the Telescope Array indicate a Weibull cutoff exp(-(E /(kB T)) σ) and permit a precise determination of the cutoff temperature kB T =(2 . 5 ± 0 . 1) × 1010 GeV and the spectral index σ = 0 . 66 ± 0 . 02. Based on the spectral number density inferred from the least-squares fit, the thermodynamics of this stationary non-equilibrium system, a multi-component mixture of relativistic nuclei, is developed. The derivative of entropy with respect to internal energy defines the effective temperature of the nuclei, S,U = 1 /Teff ,kBTeff ≈ 16 . 1 GeV, and the functional dependence between the cutoff temperature in the Weibull exponential and the effective gas temperature is determined. The equipartition ratio is found to be U /(NkBTeff) ≈ 0 . 30. The isochoric and isobaric heat capacities of the nuclear gas are calculated, as well as the isothermal and adiabatic compressibilities and the isobaric expansion coefficient, and it is shown that this non-equilibrated relativistic gas mixture satisfies the thermodynamic inequalities 0

  3. An extended formula for the energy spectrum of sputtered atoms from a material irradiated by light ions

    NASA Astrophysics Data System (ADS)

    Ono, T.; Aoki, Y.; Kawamura, T.; Kenmotsu, T.; Yamamura, Y.

    2005-03-01

    We extend a formula proposed by Kenmotsu et al. (hereafter Paper I), which fits with the energy spectrum of atoms sputtered from a heavy material hit by low-energy light ions (H +, D +, T +, He +) by taking into account an inelastic energy loss neglected in Paper I. We assume that primary knock-on atoms produced by ions backscattered at large angles do not lose energy while penetrating the material up to the surface, instead of the energy-loss model used in Paper I. The extended formula is expressed in terms of a normalized energy-distribution function and is compared with the data calculated with the ACAT code for 50 eV, 100 eV and 1 keV D + ions impinging on a Fe target. Our formula fits well with the data in a wide range of incident energy.

  4. A statistical adjustment approach for climate projections of snow conditions in mountain regions using energy balance land surface models

    NASA Astrophysics Data System (ADS)

    Verfaillie, Deborah; Déqué, Michel; Morin, Samuel; Lafaysse, Matthieu

    2017-04-01

    Projections of future climate change have been increasingly called for lately, as the reality of climate change has been gradually accepted and societies and governments have started to plan upcoming mitigation and adaptation policies. In mountain regions such as the Alps or the Pyrenees, where winter tourism and hydropower production are large contributors to the regional revenue, particular attention is brought to current and future snow availability. The question of the vulnerability of mountain ecosystems as well as the occurrence of climate-related hazards such as avalanches and debris-flows is also under consideration. In order to generate projections of snow conditions, however, downscaling global climate models (GCMs) by using regional climate models (RCMs) is not sufficient to capture the fine-scale processes and thresholds at play. In particular, the altitudinal resolution matters, since the phase of precipitation is mainly controlled by the temperature which is altitude-dependent. Simulations from GCMs and RCMs moreover suffer from biases compared to local observations, due to their rather coarse spatial and altitudinal resolution, and often provide outputs at too coarse time resolution to drive impact models. RCM simulations must therefore be adjusted using empirical-statistical downscaling and error correction methods, before they can be used to drive specific models such as energy balance land surface models. In this study, time series of hourly temperature, precipitation, wind speed, humidity, and short- and longwave radiation were generated over the Pyrenees and the French Alps for the period 1950-2100, by using a new approach (named ADAMONT for ADjustment of RCM outputs to MOuNTain regions) based on quantile mapping applied to daily data, followed by time disaggregation accounting for weather patterns selection. We first introduce a thorough evaluation of the method using using model runs from the ALADIN RCM driven by a global reanalysis over the

  5. [Absorption spectrum study of HeLa cells treated with vacuum and low-energy ions implantation].

    PubMed

    Zhang, Feng-Qiu; Zhao, Yuan-Li; Ge, Xiang-Hong; Liu, Wei; Zhang, Guang-Shui; Qin, Guang-Yong

    2009-08-01

    Mineral oil was selected to protect HeLa cells from water evaporation during low-energy ions implantation in the present paper. Then, HeLa cells having been treated with vacuum and low-energy N+ ions implantation were used to collect ultraviolet absorption spectrum by spectrophotometer. Analytical results indicated that HeLa cells had some characteristic absorption peaks near 202 and 260 nm, respectively. And then the study also found: (1) The spectral intensity increased with the vacuum treatment time. In addition, the effect of vacuum on cellular spectrum was greater than that of mineral oil. (2) The influence of low energy N+ ions on absorption spectrum was far more than that of vacuum. (3) The spectral intensity increased with the implantation dose. According to these results, the effect of low-energy N+ ions implantation and vacuum on tumorous cells (HeLa cells), especially on the molecular configuration and component of tumorous cells (HeLa cells) was discussed. In a word, this study provides a basis for further research on the functionary mechanism of low-energy ions implantation on biomaterial.

  6. Parametrized energy spectrum of cosmic-ray protons with kinetic energies down to 1 GeV

    NASA Technical Reports Server (NTRS)

    Tan, L. C.

    1985-01-01

    A new estimation of the interstellar proton spectrum is made in which the source term of primary protons is taken from shock acceleration theory and the cosmic ray propagation calculation is based on a proposed nonuniform galactic disk model.

  7. Two-dimensional angular energy spectrum of electrons accelerated by the ultra-short relativistic laser pulse

    SciTech Connect

    Borovskiy, A. V.; Galkin, A. L.; Kalashnikov, M. P.

    2015-04-15

    The new method of calculating energy spectra of accelerated electrons, based on the parameterization by their initial coordinates, is proposed. The energy spectra of electrons accelerated by Gaussian ultra-short relativistic laser pulse at a selected angle to the axis of the optical system focusing the laser pulse in a low density gas are theoretically calculated. The two-peak structure of the electron energy spectrum is obtained. Discussed are the reasons for its appearance as well as an applicability of other models of the laser field.

  8. Application of the BINS superheated drop detector spectrometer to the {sup 9}Be(p,xn) neutron energy spectrum determination

    SciTech Connect

    Di Fulvio, A.; Ciolini, R.; Mirzajani, N.; Romei, C.; D'Errico, F.; Bedogni, R.; Esposito, J.; Zafiropoulos, D.; Colautti, P.

    2013-07-18

    In the framework of TRASCO-BNCT project, a Bubble Interactive Neutron Spectrometer (BINS) device was applied to the characterization of the angle-and energy-differential neutron spectra generated by the {sup 9}Be(p,xn)reaction. The BINS spectrometer uses two superheated emulsion detectors, sequentially operated at different temperatures and thus provides a series of six sharp threshold responses, covering the 0.1-10 MeV neutron energy range. Spectrum unfolding of the data was performed by means of MAXED code. The obtained angle, energy-differential spectra were compared with those measured with a Bonner sphere spectrometer, a silicon telescope spectrometer and literature data.

  9. The energy spectrum of cosmic ray electrons, 5-150 MeV in late 1978 and early 1979

    NASA Technical Reports Server (NTRS)

    Evenson, P.; Meyer, P.; Nandkumar, R.

    1980-01-01

    The University of Chicago cosmic ray electron detector was launched aboard the ISEE-3 spacecraft on August 12, 1978. The energy spectrum of electrons measured in 1978 is nearly identical to that measured in 1968 by OGO-5. During the period of our investigation we observe quiet time increases in the electron flux which are of Jovian origin. These increases are restricted to energies below about 25 MeV but appear to have an energy dependence that peaks around 15 MeV.

  10. An energy adjustable linearly polarized passively Q-switched bulk laser with a wedged diffusion-bonded Nd:YAG/Cr⁴⁺:YAG crystal.

    PubMed

    Cho, C Y; Cheng, H P; Chang, Y C; Tang, C Y; Chen, Y F

    2015-03-23

    An energy adjustable passively Q-switched laser is demonstrated with a composite Nd:YAG/Cr⁴⁺:YAG crystal by applying a wedged interface inside the crystal. The theoretical model of the monolithic laser resonator is explored to show the energy adjustable feature with different initial transmissions of the saturable absorber at the horizontal axis. By adjusting the pump beam location across the Nd:YAG crystal, the output pulse energy can be flexibly changed from 10.9 μJ to 17.6 μJ while maintaining the same output efficiency. The polarization state of the laser output is found to be along with the polarization of the C-mount pump diode. Finally, the behavior of the multi-transverse-mode oscillation is also discussed for eliminating the instability of the pulse train.

  11. Measurement of turbulent spatial structure and kinetic energy spectrum by exact temporal-to-spatial mapping

    NASA Astrophysics Data System (ADS)

    Buchhave, Preben; Velte, Clara M.

    2017-08-01

    We present a method for converting a time record of turbulent velocity measured at a point in a flow to a spatial velocity record consisting of consecutive convection elements. The spatial record allows computation of dynamic statistical moments such as turbulent kinetic wavenumber spectra and spatial structure functions in a way that completely bypasses the need for Taylor's hypothesis. The spatial statistics agree with the classical counterparts, such as the total kinetic energy spectrum, at least for spatial extents up to the Taylor microscale. The requirements for applying the method are access to the instantaneous velocity magnitude, in addition to the desired flow quantity, and a high temporal resolution in comparison to the relevant time scales of the flow. We map, without distortion and bias, notoriously difficult developing turbulent high intensity flows using three main aspects that distinguish these measurements from previous work in the field: (1) The measurements are conducted using laser Doppler anemometry and are therefore not contaminated by directional ambiguity (in contrast to, e.g., frequently employed hot-wire anemometers); (2) the measurement data are extracted using a correctly and transparently functioning processor and are analysed using methods derived from first principles to provide unbiased estimates of the velocity statistics; (3) the exact mapping proposed herein has been applied to the high turbulence intensity flows investigated to avoid the significant distortions caused by Taylor's hypothesis. The method is first confirmed to produce the correct statistics using computer simulations and later applied to measurements in some of the most difficult regions of a round turbulent jet—the non-equilibrium developing region and the outermost parts of the developed jet. The proposed mapping is successfully validated using corresponding directly measured spatial statistics in the fully developed jet, even in the difficult outer regions of

  12. Investigation on the energy spectrums of electrons in atmospheric pressure argon plasma jets and their dependences on the applied voltage

    NASA Astrophysics Data System (ADS)

    Chen, Xinxian; Tan, Zhenyu; Liu, Yadi; Li, Xiaotong; Pan, Jie; Wang, Xiaolong

    2017-08-01

    This work presents a systematical investigation on the spatiotemporal evolution of the energy spectrum of electrons in atmospheric pressure argon plasma jets and its dependence on the applied voltage. The investigations are carried out by means of the numerical simulation based on a particle-in-cell Monte-Carlo collision model. The characteristics of the spatiotemporal evolution of the energy spectrum of electrons (ESE) in the discharge space have been presented, and especially the mechanisms of inducing these characteristics have also been revealed. The present work shows the following conclusions. In the evolution of ESE, there is a characteristic time under each applied voltage. Before the characteristic time, the peak value of ESE decreases, the peak position shifts toward high energy, and the distribution of ESE becomes wider and wider, but the reverse is true after the characteristic time. The formation of these characteristics can be mainly attributed to the transport of electrons toward a low electric field as well as a balance between the energy gained from the electric field including the effect of space charges and the energy loss due to inelastic collisions in the process of electron transport. The characteristic time decreases with the applied voltage. In addition, the average energy of electrons at the characteristic time can be increased by enhancing the applied voltage. The results presented in this work are of importance for regulating and controlling the energy of electrons in the plasma jets applied to plasma medicine.

  13. An Energy-Efficient Spectrum-Aware Reinforcement Learning-Based Clustering Algorithm for Cognitive Radio Sensor Networks.

    PubMed

    Mustapha, Ibrahim; Mohd Ali, Borhanuddin; Rasid, Mohd Fadlee A; Sali, Aduwati; Mohamad, Hafizal

    2015-08-13

    It is well-known that clustering partitions network into logical groups of nodes in order to achieve energy efficiency and to enhance dynamic channel access in cognitive radio through cooperative sensing. While the topic of energy efficiency has been well investigated in conventional wireless sensor networks, the latter has not been extensively explored. In this paper, we propose a reinforcement learning-based spectrum-aware clustering algorithm that allows a member node to learn the energy and cooperative sensing costs for neighboring clusters to achieve an optimal solution. Each member node selects an optimal cluster that satisfies pairwise constraints, minimizes network energy consumption and enhances channel sensing performance through an exploration technique. We first model the network energy consumption and then determine the optimal number of clusters for the network. The problem of selecting an optimal cluster is formulated as a Markov Decision Process (MDP) in the algorithm and the obtained simulation results show convergence, learning and adaptability of the algorithm to dynamic environment towards achieving an optimal solution. Performance comparisons of our algorithm with the Groupwise Spectrum Aware (GWSA)-based algorithm in terms of Sum of Square Error (SSE), complexity, network energy consumption and probability of detection indicate improved performance from the proposed approach. The results further reveal that an energy savings of 9% and a significant Primary User (PU) detection improvement can be achieved with the proposed approach.

  14. An Energy-Efficient Spectrum-Aware Reinforcement Learning-Based Clustering Algorithm for Cognitive Radio Sensor Networks

    PubMed Central

    Mustapha, Ibrahim; Ali, Borhanuddin Mohd; Rasid, Mohd Fadlee A.; Sali, Aduwati; Mohamad, Hafizal

    2015-01-01

    It is well-known that clustering partitions network into logical groups of nodes in order to achieve energy efficiency and to enhance dynamic channel access in cognitive radio through cooperative sensing. While the topic of energy efficiency has been well investigated in conventional wireless sensor networks, the latter has not been extensively explored. In this paper, we propose a reinforcement learning-based spectrum-aware clustering algorithm that allows a member node to learn the energy and cooperative sensing costs for neighboring clusters to achieve an optimal solution. Each member node selects an optimal cluster that satisfies pairwise constraints, minimizes network energy consumption and enhances channel sensing performance through an exploration technique. We first model the network energy consumption and then determine the optimal number of clusters for the network. The problem of selecting an optimal cluster is formulated as a Markov Decision Process (MDP) in the algorithm and the obtained simulation results show convergence, learning and adaptability of the algorithm to dynamic environment towards achieving an optimal solution. Performance comparisons of our algorithm with the Groupwise Spectrum Aware (GWSA)-based algorithm in terms of Sum of Square Error (SSE), complexity, network energy consumption and probability of detection indicate improved performance from the proposed approach. The results further reveal that an energy savings of 9% and a significant Primary User (PU) detection improvement can be achieved with the proposed approach. PMID:26287191

  15. The energy spectrum of Telescope Array's Middle Drum detector and the direct comparison to the High Resolution Fly's Eye experiment

    NASA Astrophysics Data System (ADS)

    Abu-Zayyad, T.; Aida, R.; Allen, M.; Anderson, R.; Azuma, R.; Barcikowski, E.; Belz, J. W.; Bergman, D. R.; Blake, S. A.; Cady, R.; Cheon, B. G.; Chiba, J.; Chikawa, M.; Cho, E. J.; Cho, W. R.; Fujii, H.; Fujii, T.; Fukuda, T.; Fukushima, M.; Gorbunov, D.; Hanlon, W.; Hayashi, K.; Hayashi, Y.; Hayashida, N.; Hibino, K.; Hiyama, K.; Honda, K.; Iguchi, T.; Ikeda, D.; Ikuta, K.; Inoue, N.; Ishii, T.; Ishimori, R.; Ivanov, D.; Iwamoto, S.; Jui, C. C. H.; Kadota, K.; Kakimoto, F.; Kalashev, O.; Kanbe, T.; Kasahara, K.; Kawai, H.; Kawakami, S.; Kawana, S.; Kido, E.; Kim, H. B.; Kim, H. K.; Kim, J. H.; Kitamoto, K.; Kitamura, S.; Kitamura, Y.; Kobayashi, K.; Kobayashi, Y.; Kondo, Y.; Kuramoto, K.; Kuzmin, V.; Kwon, Y. J.; Lim, S. I.; Machida, S.; Martens, K.; Martineau, J.; Matsuda, T.; Matsuura, T.; Matsuyama, T.; Matthews, J. N.; Myers, I.; Minamino, M.; Miyata, K.; Murano, Y.; Nagataki, S.; Nakamura, T.; Nam, S. W.; Nonaka, T.; Ogio, S.; Ohnishi, M.; Ohoka, H.; Oki, K.; Oku, D.; Okuda, T.; Oshima, A.; Ozawa, S.; Park, I. H.; Pshirkov, M. S.; Rodriguez, D. C.; Roh, S. Y.; Rubtsov, G.; Ryu, D.; Sagawa, H.; Sakurai, N.; Sampson, A. L.; Scott, L. M.; Shah, P. D.; Shibata, F.; Shibata, T.; Shimodaira, H.; Shin, B. K.; Shin, J. I.; Shirahama, T.; Smith, J. D.; Sokolsky, P.; Sonley, T. J.; Springer, R. W.; Stokes, B. T.; Stratton, S. R.; Stroman, T. A.; Suzuki, S.; Takahashi, Y.; Takeda, M.; Taketa, A.; Takita, M.; Tameda, Y.; Tanaka, H.; Tanaka, K.; Tanaka, M.; Thomas, S. B.; Thomson, G. B.; Tinyakov, P.; Tkachev, I.; Tokuno, H.; Tomida, T.; Troitsky, S.; Tsunesada, Y.; Tsutsumi, K.; Tsuyuguchi, Y.; Uchihori, Y.; Udo, S.; Ukai, H.; Vasiloff, G.; Wada, Y.; Wong, T.; Wood, M.; Yamakawa, Y.; Yamane, R.; Yamaoka, H.; Yamazaki, K.; Yang, J.; Yoneda, Y.; Yoshida, S.; Yoshii, H.; Zollinger, R.; Zundel, Z.

    2012-12-01

    The Telescope Array's Middle Drum fluorescence detector was instrumented with telescopes refurbished from the High Resolution Fly's Eye's HiRes-1 site. The data observed by Middle Drum in monocular mode was analyzed via the HiRes-1 profile-constrained geometry reconstruction technique and utilized the same calibration techniques enabling a direct comparison of the energy spectra and energy scales between the two experiments. The spectrum measured using the Middle Drum telescopes is based on a three-year exposure collected between December 16, 2007 and December 16, 2010. The calculated difference between the spectrum of the Middle Drum observations and the published spectrum obtained by the data collected by the HiRes-1 site allows the HiRes-1 energy scale to be transferred to Middle Drum. The HiRes energy scale is applied to the entire Telescope Array by making a comparison between Middle Drum monocular events and hybrid events that triggered both Middle Drum and the Telescope Array's scintillator ground array.

  16. Replacement of Bonner spheres with polyethylene cylinders for the unfolding of an (241)Am-Be neutron energy spectrum.

    PubMed

    Ghal-Eh, N; Kalaei, M; Mohammadi, A; Vega-Carrillo, H R

    2017-10-01

    In this study, a conventional Bonner sphere spectrometer, together with (6)LiI(Eu) inorganic scintillator used as the central detector, was used to obtain the neutron energy spectrum of an (241)Am-Be source. To achieve this, we calculated the response matrices corresponding to eight different sizes of polyethylene spheres for the neutron energies ranging from about 10(-7) to 15MeV in 54 energy groups by using the MCNPX2.6 code, and the (241)Am-Be neutron spectrum was obtained using a modified version of the neutron spectrum unfolding code, AFITBUNKI. In a feasibility study, similar calculations were performed with different sizes of polyethylene cylinders. A comparison between the unfolded spectra of a typical (241)Am-Be neutron source with those of Bonner spheres, cylinders of similar sizes, and standard (241)Am-Be neutron energy spectra shows that the spectrometer with polyethylene cylinders can be used as a potential alternative for conventional Bonner spheres. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Measurement of the neutron energy spectrum on the Godiva IV fast burst assembly for application to neutron dosimetry studies

    SciTech Connect

    Casson, W.H.; Hsu, H.H.; Paternoster, R.R.; Butterfield, K.B.

    1996-06-01

    In June, 1995, Los Alamos National Laboratory hosted the 23rd U.S. Department of Energy sponsored Nuclear Accident Dosimetry Study at the Los Alamos Critical Experiments Facility. The participants tested their facilities accident dosimeters under a variety of neutrons fields produced by the Solution High Energy Burst Assembly (SHEBA) and the Godiva IV fast burst assembly. To provide useful information for the evaluation of the results, the neutron energy Spectrum was determined and the delivered absorbed dose to tissue. The measurement of the neutron energy spectrum on Godiva provides a unique problem in that the burst, which is nearly Gaussian in time, has a full width at half maximum of around 50 microseconds. The neutron spectrum was first determined at low-power while running at delayed critical using a standard set of Bonner spheres. At the same time, the response of a set of TLD dosimeters were measured. After that, measurements were conducted during a burst with another set of TLDs and with sulfur pellets.

  18. Examination of the calorimetric spectrum to determine the neutrino mass in low-energy electron capture decay

    NASA Astrophysics Data System (ADS)

    Robertson, R. G. H.

    2015-03-01

    Background: The standard kinematic method for determining neutrino mass from the β decay of tritium or other isotope is to measure the shape of the electron spectrum near the endpoint. A similar distortion of the "visible energy" remaining after electron capture is caused by neutrino mass. There has been a resurgence of interest in using this method with 163Ho, driven by technological advances in microcalorimetry. Recent theoretical analyses offer reassurance that there are no significant theoretical uncertainties. Purpose: The theoretical analyses consider only single vacancy states in the daughter 163Dy atom. It is necessary to consider configurations with more than one vacancy that can be populated owing to the change in nuclear charge. Method: The shakeup and shake-off theory of Carlson and Nestor is used as a basis for estimating the population of double-vacancy states. Results: A spectrum of satellites associated with each primary vacancy created by electron capture is presented. Conclusions: The theory of the calorimetric spectrum is more complicated than has been described heretofore. There are numerous shakeup and shake-off satellites present across the spectrum, and some may be very near the endpoint. The spectrum shape is presently not understood well enough to permit a sensitive determination of the neutrino mass in this way.

  19. Evidence for variability of the hard X-ray feature in the Hercules X-1 energy spectrum

    NASA Technical Reports Server (NTRS)

    Tueller, J.; Cline, T. L.; Teegarden, B. J.; Paciesas, W. S.; Boclet, D.; Durochoux, P.; Hameury, J. M.; Prantzos, N.; Haymes, R. C.

    1983-01-01

    The hard X-ray spectrum of HER X-1 was measured for the first time with a high resolution (1.4 keV FWHM) germanium spectrometer. The observation was performed near the peak of the on-state in the 35 day cycle and the 1.24 pulsations were observed between the energies of 20 keV and 70 keV. The feature corresponds to an excess of 7.5 sigma over the low energy continuum. Smooth continuum models are poor fits to the entire energy range (chance probabilities of 2 percent or less). The best fit energies are 35 keV for an absorption line and 39 keV for an emission line. These are significantly lower energies than those derived from previous experiments. A direct comparison of our data with the results of the MPI/AIT group shows statistically significant variations which strongly suggest variability in the source.

  20. Scaling Laws of the Two-Electron Sum-Energy Spectrum in Strong-Field Double Ionization.

    PubMed

    Ye, Difa; Li, Min; Fu, Libin; Liu, Jie; Gong, Qihuang; Liu, Yunquan; Ullrich, J

    2015-09-18

    The sum-energy spectrum of two correlated electrons emitted in nonsequential strong-field double ionization (SFDI) of Ar was studied for intensities of 0.3 to 2×10^{14} W/cm^{2}. We find the mean sum energy, the maximum of the distributions as well as the high-energy tail of the scaled (to the ponderomotive energy) spectra increase with decreasing intensity below the recollision threshold (BRT). At higher intensities the spectra collapse into a single distribution. This behavior can be well explained within a semiclassical model providing clear evidence of the importance of multiple recollisions in the BRT regime. Here, ultrafast thermalization between both electrons is found occurring within three optical cycles only and leaving its clear footprint in the sum-energy spectra.

  1. Linearity of the edge states energy spectrum in the 2D topological insulator

    NASA Astrophysics Data System (ADS)

    Entin, M. V.; Mahmoodian, M. M.; Magarill, L. I.

    2017-06-01

    Linearity of the topological insulator edge state spectrum plays a crucial role for various transport phenomena. Previous studies found that this linearity exists near the spectrum crossing point, but did not determine how perfect the linearity is. The purpose of the present study is to answer this question in various edge states models. We examine Volkov and Pankratov (VP) model for the Dirac Hamiltonian and the model BHZ for the Bernevig, Hughes and Zhang (BHZ) Hamiltonian with zero boundary conditions. It is found that both models yield ideally linear edge states. In the BHZ1 model the linearity is conserved up to the spectrum ending points corresponding to the tangency of the edge spectrum with the boundary of 2D states. In contrast, the model BHZ2 with mixed boundary conditions for BHZ Hamiltonian and the 2D tight-binding (TB) model yield weak nonlinearity.

  2. Improvement of energy efficiency via spectrum optimization of excitation sequence for multichannel simultaneously triggered airborne sonar system.

    PubMed

    Meng, Qing-Hao; Yao, Zhen-Jing; Peng, Han-Yang

    2009-12-01

    Both the energy efficiency and correlation characteristics are important in airborne sonar systems to realize multichannel ultrasonic transducers working together. High energy efficiency can increase echo energy and measurement range, and sharp autocorrelation and flat cross correlation can help eliminate cross-talk among multichannel transducers. This paper addresses energy efficiency optimization under the premise that cross-talk between different sonar transducers can be avoided. The nondominated sorting genetic algorithm-II is applied to optimize both the spectrum and correlation characteristics of the excitation sequence. The central idea of the spectrum optimization is to distribute most of the energy of the excitation sequence within the frequency band of the sonar transducer; thus, less energy is filtered out by the transducers. Real experiments show that a sonar system consisting of eight-channel Polaroid 600 series electrostatic transducers excited with 2 ms optimized pulse-position-modulation sequences can work together without cross-talk and can measure distances up to 650 cm with maximal 1% relative error.

  3. Some problems of the theory of quantum statistical systems with an energy spectrum of the fractional-power type

    NASA Astrophysics Data System (ADS)

    Alisultanov, Z. Z.; Meilanov, R. P.

    2012-10-01

    We consider the problem of the effective interaction potential in a quantum many-particle system leading to the fractional-power dispersion law. We show that passing to fractional-order derivatives is equivalent to introducing a pair interparticle potential. We consider the case of a degenerate electron gas. Using the van der Waals equation, we study the equation of state for systems with a fractional-power spectrum. We obtain a relation between the van der Waals constant and the phenomenological parameter α, the fractional-derivative order. We obtain a relation between energy, pressure, and volume for such systems: the coefficient of the thermal energy is a simple function of α. We consider Bose—Einstein condensation in a system with a fractional-power spectrum. The critical condensation temperature for 1 < α < 2 is greater in the case under consideration than in the case of an ideal system, where α = 2.

  4. Beam collimation and energy spectrum compression of laser-accelerated proton beams using solenoid field and RF cavity

    NASA Astrophysics Data System (ADS)

    Teng, J.; Gu, Y. Q.; Zhu, B.; Hong, W.; Zhao, Z. Q.; Zhou, W. M.; Cao, L. F.

    2013-11-01

    This paper presents a new method of laser produced proton beam collimation and spectrum compression using a combination of a solenoid field and a RF cavity. The solenoid collects laser-driven protons efficiently within an angle that is smaller than 12 degrees because it is mounted few millimeters from the target, and collimates protons with energies around 2.3 MeV. The collimated proton beam then passes through a RF cavity to allow compression of the spectrum. Particle-in-cell (PIC) simulations demonstrate the proton beam transport in the solenoid and RF electric fields. Excellent energy compression and collection efficiency of protons are presented. This method for proton beam optimization is suitable for high repetition-rate laser acceleration proton beams, which could be used as an injector for a conventional proton accelerator.

  5. Study of the very high energy gamma-ray spectrum from the Galactic Center and future prospects

    NASA Astrophysics Data System (ADS)

    Belikov, Alexander V.; Moulin, Emmanuel; Silk, Joseph

    2016-11-01

    Ground-based gamma-ray observations of the Galactic Center region have revealed a high energy gamma-ray source spatially coincident with the gravitational centroid of our Galaxy. The pointlike emission detected by HESS exhibits an energy cutoff at about 10 TeV. We identify the parameters of the best fit of the exponential and the superexponential cutoff models to the spectrum of the pointlike source and find that the superexponential one provides a similar quality of fit to the spectrum of the pointlike source as the best-fit exponential cutoff model, while a dark matter interpretation does not provide as good a fit in the whole energy range of the signal. Based on the magnitude of the flux we derive constraints in the plane of the slope of the density profile γ and the critical radius, below which the density is assumed to be constant, rc. Motivated by recent results on the spectrum and morphology from HESS and by the possible observation of a superexponential cutoff, we forecast the observations of superexponential versus exponential cutoffs by the upcoming Cherenkov Telescope Array. We derive a formula for J -factor in the small-angle approximation and propose approximate morphological constraints on the central source.

  6. Proton therapy monitoring by Compton imaging: influence of the large energy spectrum of the prompt-γ radiation.

    PubMed

    Hilaire, Estelle; Sarrut, David; Peyrin, Françoise; Maxim, Voichiţa

    2016-04-21

    In proton therapy, the prompt-γ (PG) radiation produced by the interactions between protons and matter is related to the range of the beam in the patient. Tomographic Compton imaging is currently studied to establish a PG image and verify the treatment. However the quality of the reconstructed images depends on a number of factors such as the volume attenuation, the spatial and energy resolutions of the detectors, incomplete absorptions of high energy photons and noise from other particles reaching the camera. The impact of all these factors was not assessed in details. In this paper we investigate the influence of the PG energy spectrum on the reconstructed images. To this aim, we describe the process from the Monte Carlo simulation of the proton irradiation, through the Compton imaging of the PG distribution, up to the image reconstruction with a statistical MLEM method. We identify specific PG energy windows that are more relevant to detect discrepancies with the treatment plan. We find that for the simulated Compton device, the incomplete absorption of the photons with energy above about 2 MeV prevents the observation of the PG distributions at specific energies. It also leads to blurred images and smooths the distal slope of the 1D PG profiles obtained as projections on the central beam axis. We show that a selection of the events produced by γ photons having deposited almost all their energy in the camera allows to largely improve the images, a result that emphasizes the importance of the choice of the detector. However, this initial-energy-based selection is not accessible in practice. We then propose a method to estimate the range of the PG profile both for specific deposited-energy windows and for the full spectrum emission. The method relies on two parameters. We use a learning approach for their estimation and we show that it allows to detect few millimeter shifts of the PG profiles.

  7. Proton therapy monitoring by Compton imaging: influence of the large energy spectrum of the prompt-γ radiation

    NASA Astrophysics Data System (ADS)

    Hilaire, Estelle; Sarrut, David; Peyrin, Françoise; Maxim, Voichiţa

    2016-04-01

    In proton therapy, the prompt-γ (PG) radiation produced by the interactions between protons and matter is related to the range of the beam in the patient. Tomographic Compton imaging is currently studied to establish a PG image and verify the treatment. However the quality of the reconstructed images depends on a number of factors such as the volume attenuation, the spatial and energy resolutions of the detectors, incomplete absorptions of high energy photons and noise from other particles reaching the camera. The impact of all these factors was not assessed in details. In this paper we investigate the influence of the PG energy spectrum on the reconstructed images. To this aim, we describe the process from the Monte Carlo simulation of the proton irradiation, through the Compton imaging of the PG distribution, up to the image reconstruction with a statistical MLEM method. We identify specific PG energy windows that are more relevant to detect discrepancies with the treatment plan. We find that for the simulated Compton device, the incomplete absorption of the photons with energy above about 2 MeV prevents the observation of the PG distributions at specific energies. It also leads to blurred images and smooths the distal slope of the 1D PG profiles obtained as projections on the central beam axis. We show that a selection of the events produced by γ photons having deposited almost all their energy in the camera allows to largely improve the images, a result that emphasizes the importance of the choice of the detector. However, this initial-energy-based selection is not accessible in practice. We then propose a method to estimate the range of the PG profile both for specific deposited-energy windows and for the full spectrum emission. The method relies on two parameters. We use a learning approach for their estimation and we show that it allows to detect few millimeter shifts of the PG profiles.

  8. The Cosmic Ray p+He energy spectrum in the 3-3000 TeV energy range measured by ARGO-YBJ

    NASA Astrophysics Data System (ADS)

    Mari, S. M.; Montini, P.

    2016-07-01

    The ARGO-YBJ experiment is a full coverage air shower detector operated at the Yangbajing International Cosmic Ray Observatory. The detector has been in stable data taking in its full configuration since November 2007 to February 2013. The high altitude and the high segmentation and spacetime resolution offer the possibility to explore the cosmic ray energy spectrum in a very wide range, from a few TeV up to the PeV region. The high segmentation allows a detailed measurement of the lateral distribution, which can be used in order to discriminate showers produced by light and heavy elements. In this work we present the measurement of the cosmic ray light component spectrum in the energy range 3-3000 TeV. The analysis has been carried out by using a two-dimensional unfolding method based on the Bayes' theorem.

  9. ENERGY-DEPENDENT GAMMA-RAY BURST PULSE WIDTH DUE TO THE CURVATURE EFFECT AND INTRINSIC BAND SPECTRUM

    SciTech Connect

    Peng, Z. Y.; Ma, L.; Zhao, X. H.; Yin, Y.; Bao, Y. Y.

    2012-06-20

    Previous studies have found that the width of the gamma-ray burst (GRB) pulse is energy dependent and that it decreases as a power-law function with increasing photon energy. In this work we have investigated the relation between the energy dependence of the pulse and the so-called Band spectrum by using a sample including 51 well-separated fast rise and exponential decay long-duration GRB pulses observed by BATSE (Burst and Transient Source Experiment on the Compton Gamma Ray Observatory). We first decompose these pulses into rise and decay phases and find that the rise widths and the decay widths also behave as a power-law function with photon energy. Then we investigate statistically the relations between the three power-law indices of the rise, decay, and total width of the pulse (denoted as {delta}{sub r}, {delta}{sub d}, and {delta}{sub w}, respectively) and the three Band spectral parameters, high-energy index ({alpha}), low-energy index ({beta}), and peak energy (E{sub p} ). It is found that (1) {alpha} is strongly correlated with {delta}{sub w} and {delta}{sub d} but seems uncorrelated with {delta}{sub r}; (2) {beta} is weakly correlated with the three power-law indices, and (3) E{sub p} does not show evident correlations with the three power-law indices. We further investigate the origin of {delta}{sub d}-{alpha} and {delta}{sub w}-{alpha}. We show that the curvature effect and the intrinsic Band spectrum could naturally lead to the energy dependence of the GRB pulse width and also the {delta}{sub d}-{alpha} and {delta}{sub w}-{alpha} correlations. Our results hold so long as the shell emitting gamma rays has a curved surface and the intrinsic spectrum is a Band spectrum or broken power law. The strong {delta}{sub d}-{alpha} correlation and inapparent correlations between {delta}{sub r} and the three Band spectral parameters also suggest that the rise and decay phases of the GRB pulses have different origins.

  10. Prominent Soft X-ray Lines of Sr-like Au41+ in Low-energy EBIT Spectrum

    SciTech Connect

    Vilkas, M J; Ishikawa, Y; Trabert, E

    2007-03-27

    Relativistic multireference M{o}ller-Plesset perturbation theory has been employed to calculate with high accuracy the energy levels and transition probabilities of Cu- to Sr-like gold ions. The many-body calculations were carried out to identify the unassigned blended lines in the 35-40 angstroms region of the low-energy EBIT spectrum of the gold ions. Most of the prominent lines in the 35-40 angstroms region were identified as the emission lines in Sr-like gold.

  11. Silver enhanced ratiometric nanosensor based on two adjustable Fluorescence Resonance Energy Transfer modes for quantitative protein sensing.

    PubMed

    Li, Hui; Zhao, Yaju; Chen, Zhu; Xu, Danke

    2017-01-15

    We developed a silver decahedral nanoparticles (Ag10NPs)-enhanced ratiometric Fluorescence Resonance Energy Transfer (FRET) nanosensor based on two adjustable FRET modes. Alexa Fluor 488 (Alexa) and Cyanine3 (Cy3)-aptamer-Black hole quencher-2 (BHQ-2) were bound with Ag10NPs to form the ratiometric FRET nanosensor (Ag-Alexa/Cy3/BHQ-2). Alexa act as donor and Cy3 as acceptor in the FRET mode 1 while Cy3 was donor and BHQ-2 was acceptor in the FRET mode 2. In the absence of platelet-derived growth factor (PDGF-BB), the fluorescence intensity of Alexa was lowest while that of Cy3 was highest. Upon the addition of PDGF-BB, Cy3-aptamer-BHQ-2 binds with PDGF-BB resulting in the change of structure of aptamer. The fluorescence intensity of Alexa increased while that of Cy3 decreased. In addition, the fluorescence intensity ratio of Alexa to Cy3 increased remarkably with PDGF-BB concentration in the range of 0.4-400ng/mL. A good linear response was obtained when the PDGF-BB concentrations were in the range of 3.1-200ng/mL, with the limit of detection at 0.4ng/mL. When compared to sensors without Ag10NPs (Alexa/Cy3/BHQ-2) and one without BHQ-2 (Ag-Alexa/Cy3), the new nanosensor Ag-Alexa/Cy3/BHQ-2 showed remarkable increase in sensitivity.

  12. Cosmic ray charge and energy spectrum measurements using a new large area Cerenkov x dE/dx telescope

    NASA Technical Reports Server (NTRS)

    Webber, W. R.; Kish, J. C.; Schrier, D. A.

    1985-01-01

    In September, 1981, a new 0.5 square meter ster cosmic ray telescope was flown to study the charge composition and energy spectrum of cosmic ray nuclei between 0.3 and 4 GeV/nuc. A high resolution Cerenkov counter, and three dE/dx measuring scintillation counters, including two position scintillators were contained in the telescope used for the charge and energy spectrum measurements. The analysis procedures did not require any large charge or energy dependent corrections, and absolute fluxes could be obtained to an accuracy approximately 5%. The spectral measurements made in 1981, at a time of extreme solar modulation, could be compared with measurements with a similar telescope made by our group in 1977, at a time of minimum modulation and can be used to derive absolute intensity values for the HEAO measurements made in 1979 to 80. Using both data sets precise energy spectra and abundance ratios can be derived over the entire energy range from 0.3 to greater than 15 GeV/nuc.

  13. An analytical model of the effects of pulse pileup on the energy spectrum recorded by energy resolved photon counting x-ray detectors

    PubMed Central

    Taguchi, Katsuyuki; Frey, Eric C.; Wang, Xiaolan; Iwanczyk, Jan S.; Barber, William C.

    2010-01-01

    Purpose: Recently, novel CdTe photon counting x-ray detectors (PCXDs) with energy discrimination capabilities have been developed. When such detectors are operated under a high x-ray flux, however, coincident pulses distort the recorded energy spectrum. These distortions are called pulse pileup effects. It is essential to compensate for these effects on the recorded energy spectrum in order to take full advantage of spectral information PCXDs provide. Such compensation can be achieved by incorporating a pileup model into the image reconstruction process for computed tomography, that is, as a part of the forward imaging process, and iteratively estimating either the imaged object or the line integrals using, e.g., a maximum likelihood approach. The aim of this study was to develop a new analytical pulse pileup model for both peak and tail pileup effects for nonparalyzable detectors. Methods: The model takes into account the following factors: The bipolar shape of the pulse, the distribution function of time intervals between random events, and the input probability density function of photon energies. The authors used Monte Carlo simulations to evaluate the model. Results: The recorded spectra estimated by the model were in an excellent agreement with those obtained by Monte Carlo simulations for various levels of pulse pileup effects. The coefficients of variation (i.e., the root mean square difference divided by the mean of measurements) were 5.3%–10.0% for deadtime losses of 1%–50% with a polychromatic incident x-ray spectrum. Conclusions: The proposed pulse pileup model can predict recorded spectrum with relatively good accuracy. PMID:20879558

  14. Cosmic ray proton plus helium energy spectrum measured by the ARGO-YBJ experiment in the energy range 3-300 TeV

    NASA Astrophysics Data System (ADS)

    Bartoli, B.; Bernardini, P.; Bi, X. J.; Cao, Z.; Catalanotti, S.; Chen, S. Z.; Chen, T. L.; Cui, S. W.; Dai, B. Z.; D'Amone, A.; Danzengluobu, De Mitri, I.; D'Ettorre Piazzoli, B.; Di Girolamo, T.; Di Sciascio, G.; Feng, C. F.; Feng, Zhaoyang; Feng, Zhenyong; Gou, Q. B.; Guo, Y. Q.; He, H. H.; Hu, Haibing; Hu, Hongbo; Iacovacci, M.; Iuppa, R.; Jia, H. Y.; Labaciren, Li, H. J.; Liu, C.; Liu, J.; Liu, M. Y.; Lu, H.; Ma, L. L.; Ma, X. H.; Mancarella, G.; Mari, S. M.; Marsella, G.; Mastroianni, S.; Montini, P.; Ning, C. C.; Perrone, L.; Pistilli, P.; Salvini, P.; Santonico, R.; Settanta, G.; Shen, P. R.; Sheng, X. D.; Shi, F.; Surdo, A.; Tan, Y. H.; Vallania, P.; Vernetto, S.; Vigorito, C.; Wang, H.; Wu, C. Y.; Wu, H. R.; Xue, L.; Yang, Q. Y.; Yang, X. C.; Yao, Z. G.; Yuan, A. F.; Zha, M.; Zhang, H. M.; Zhang, L.; Zhang, X. Y.; Zhang, Y.; Zhao, J.; Zhaxiciren, Zhaxisangzhu, Zhou, X. X.; Zhu, F. R.; Zhu, Q. Q.; ARGO-YBJ Collaboration

    2015-06-01

    The ARGO-YBJ experiment is a full-coverage air shower detector located at the Yangbajing Cosmic Ray Observatory (Tibet, People's Republic of China, 4300 m a.s.l.). The high altitude, combined with the full-coverage technique, allows the detection of extensive air showers in a wide energy range and offer the possibility of measuring the cosmic ray proton plus helium spectrum down to the TeV region, where direct balloon/space-borne measurements are available. The detector has been in stable data taking in its full configuration from November 2007 to February 2013. In this paper the measurement of the cosmic ray proton plus helium energy spectrum is presented in the region 3-300 TeV by analyzing the full collected data sample. The resulting spectral index is γ =-2.64 ±0.01 , the error is dominated by systematic uncertainties. The accurate measurement of the spectrum of light elements with a ground based air shower detector demonstrates the possibility of extending these measurements at larger energies, where galactic cosmic ray sources should run out of power in accelerating light elements.

  15. Single-wave-number representation of nonlinear energy spectrum in elastic-wave turbulence of the Föppl-von Kármán equation: Energy decomposition analysis and energy budget

    NASA Astrophysics Data System (ADS)

    Yokoyama, Naoto; Takaoka, Masanori

    2014-12-01

    A single-wave-number representation of a nonlinear energy spectrum, i.e., a stretching-energy spectrum, is found in elastic-wave turbulence governed by the Föppl-von Kármán (FvK) equation. The representation enables energy decomposition analysis in the wave-number space and analytical expressions of detailed energy budgets in the nonlinear interactions. We numerically solved the FvK equation and observed the following facts. Kinetic energy and bending energy are comparable with each other at large wave numbers as the weak turbulence theory suggests. On the other hand, stretching energy is larger than the bending energy at small wave numbers, i.e., the nonlinearity is relatively strong. The strong correlation between a mode ak and its companion mode a-k is observed at the small wave numbers. The energy is input into the wave field through stretching-energy transfer at the small wave numbers, and dissipated through the quartic part of kinetic-energy transfer at the large wave numbers. Total-energy flux consistent with energy conservation is calculated directly by using the analytical expression of the total-energy transfer, and the forward energy cascade is observed clearly.

  16. Single-wave-number representation of nonlinear energy spectrum in elastic-wave turbulence of the Föppl-von Kármán equation: energy decomposition analysis and energy budget.

    PubMed

    Yokoyama, Naoto; Takaoka, Masanori

    2014-12-01

    A single-wave-number representation of a nonlinear energy spectrum, i.e., a stretching-energy spectrum, is found in elastic-wave turbulence governed by the Föppl-von Kármán (FvK) equation. The representation enables energy decomposition analysis in the wave-number space and analytical expressions of detailed energy budgets in the nonlinear interactions. We numerically solved the FvK equation and observed the following facts. Kinetic energy and bending energy are comparable with each other at large wave numbers as the weak turbulence theory suggests. On the other hand, stretching energy is larger than the bending energy at small wave numbers, i.e., the nonlinearity is relatively strong. The strong correlation between a mode a(k) and its companion mode a(-k) is observed at the small wave numbers. The energy is input into the wave field through stretching-energy transfer at the small wave numbers, and dissipated through the quartic part of kinetic-energy transfer at the large wave numbers. Total-energy flux consistent with energy conservation is calculated directly by using the analytical expression of the total-energy transfer, and the forward energy cascade is observed clearly.

  17. A novel neutron energy spectrum unfolding code using particle swarm optimization

    NASA Astrophysics Data System (ADS)

    Shahabinejad, H.; Sohrabpour, M.

    2017-07-01

    A novel neutron Spectrum Deconvolution using Particle Swarm Optimization (SDPSO) code has been developed to unfold the neutron spectrum from a pulse height distribution and a response matrix. The Particle Swarm Optimization (PSO) imitates the bird flocks social behavior to solve complex optimization problems. The results of the SDPSO code have been compared with those of the standard spectra and recently published Two-steps Genetic Algorithm Spectrum Unfolding (TGASU) code. The TGASU code have been previously compared with the other codes such as MAXED, GRAVEL, FERDOR and GAMCD and shown to be more accurate than the previous codes. The results of the SDPSO code have been demonstrated to match well with those of the TGASU code for both under determined and over-determined problems. In addition the SDPSO has been shown to be nearly two times faster than the TGASU code.

  18. Novel patterns of torsion-inversion-rotation energy levels in the ν11 asymmetric CH-stretch spectrum of methylamine

    NASA Astrophysics Data System (ADS)

    Dawadi, Mahesh B.; Michael Lindsay, C.; Chirokolava, Andrei; Perry, David S.; Xu, Li-Hong

    2013-03-01

    The high-resolution infrared spectrum of methylamine (CH3NH2) has been recorded using slit-jet direct absorption spectroscopy in the ν11 CH-stretch region (2965-3005 cm-1) with a resolution of 0.0025 cm-1. The 621 lines assigned by ground state combination differences represent 27 substates with |K'| ≤ 2 for the A, B, E1, and E2 symmetries. The spectrum of CH3NH2 is complicated by torsion and inversion tunneling connecting six equivalent minima. The upper states K' = 0, ± 1 for E1 and E2 are substantially perturbed by "dark" states. The result in the spectrum is multiplets of 2 or 3 states with mixed bright/dark character. The analysis of the spectrum reveals two qualitative differences in the energy level pattern relative to the vibrational ground state and relative to available data on the lower frequency vibrations (NH2 wag and CN stretch). First at J' = 0, there is a different ordering of the levels connected by torsion-inversion tunneling. Second, the low-J splittings indicative of torsion-rotation coupling are greatly reduced in the ν11 excited state relative to the vibrational ground state for both the E1 and E2 species, suggesting the partial suppression of torsional tunneling in the ν11 CH-stretch excited state.

  19. ADAPTIVE FULL-SPECTRUM SOLAR ENERGY SYSTEMS CROSS-CUTTING R&D ON ADAPTIVE FULL-SPECTRUM SOLAR ENERGY SYSTEMS FOR MORE EFFICIENT AND AFFORDABLE USE OF SOLAR ENERGY IN BUILDINGS AND HYBRID PHOTOBIOREACTORS

    SciTech Connect

    Byard D. Wood; Jeff D. Muhs

    2004-08-01

    This RD&D project is a three year team effort to develop a hybrid solar lighting (HSL) system that transports daylight from a paraboloidal dish concentrator to a luminaire via a bundle of small core or a large core polymer fiber optics. The luminaire can be a device to distribute sunlight into a space for the production of algae or it can be a device that is a combination of daylighting and electric lighting for space/task lighting. In this project, the sunlight is collected using a one-meter paraboloidal concentrator dish with two-axis tracking. For the second generation (alpha) system, the secondary mirror is an ellipsoidal mirror that directs the visible light into a bundle of small-core fibers. The IR spectrum is filtered out to minimize unnecessary heating at the fiber entrance region. This report describes the following investigations of various aspects of the system. Taken as a whole, they confirm significant progress towards the technical feasibility and commercial viability of this technology. (1) TRNSYS Modeling of a Hybrid Lighting System: Building Energy Loads and Chromaticity Analysis; (2) High Lumens Screening Test Setup for Optical Fibers; (3) Photo-Induced Heating in Plastic Optical Fiber Bundles; (4) Low-Cost Primary Mirror Development; (5) Potential Applications for Hybrid Solar Lighting; (6) Photobioreactor Population Experiments and Productivity Measurements; and (7) Development of a Microalgal CO2-Biofixation Photobioreactor.

  20. Cosmic-ray energy spectrum and composition up to the ankle: the case for a second Galactic component

    NASA Astrophysics Data System (ADS)

    Thoudam, S.; Rachen, J. P.; van Vliet, A.; Achterberg, A.; Buitink, S.; Falcke, H.; Hörandel, J. R.

    2016-10-01

    Motivated by the recent high-precision measurements of cosmic rays by several new-generation experiments, we have carried out a detailed study to understand the observed energy spectrum and composition of cosmic rays with energies up to about 1018 eV. Our study shows that a single Galactic component with subsequent energy cut-offs in the individual spectra of different elements, optimised to explain the observed elemental spectra below 1014 eV and the "knee" in the all-particle spectrum, cannot explain the observed all-particle spectrum above 2 × 1016 eV. We discuss two approaches for a second component of Galactic cosmic rays - re-acceleration at a Galactic wind termination shock, and supernova explosions of Wolf-Rayet stars, and show that the latter scenario can explain almost all observed features in the all-particle spectrum and the composition up to 1018 eV, when combined with a canonical extra-galactic spectrum expected from strong radio galaxies or a source population with similar cosmological evolution. In this two-component Galactic model, the knee at 3 × 1015 eV and the "second knee" at 1017 eV in the all-particle spectrum are due to the cut-offs in the first and second components, respectively. We also discuss several variations of the extra-galactic component, from a minimal contribution to scenarios with a significant component below the "ankle" (at 4 × 1018 eV), and find that extra-galactic contributions in excess of regular source evolution are neither indicated nor in conflict with the existing data. We also provide arguments that an extra-galactic contribution is unlikely to dominate at or below the second knee. Our main result is that the second Galactic component predicts a composition of Galactic cosmic rays at and above the second knee that largely consists of helium or a mixture of helium and CNO nuclei, with a weak or essentially vanishing iron fraction, in contrast to most common assumptions. This prediction is in agreement with new

  1. A multiple-time-scale turbulence model based on variable partitioning of the turbulent kinetic energy spectrum

    NASA Technical Reports Server (NTRS)

    Kim, S.-W.; Chen, C.-P.

    1989-01-01

    A multiple-time-scale turbulence model of a single point closure and a simplified split-spectrum method is presented. In the model, the effect of the ratio of the production rate to the dissipation rate on eddy viscosity is modeled by use of the multiple-time-scales and a variable partitioning of the turbulent kinetic energy spectrum. The concept of a variable partitioning of the turbulent kinetic energy spectrum and the rest of the model details are based on the previously reported algebraic stress turbulence model. Example problems considered include: a fully developed channel flow, a plane jet exhausting into a moving stream, a wall jet flow, and a weakly coupled wake-boundary layer interaction flow. The computational results compared favorably with those obtained by using the algebraic stress turbulence model as well as experimental data. The present turbulence model, as well as the algebraic stress turbulence model, yielded significantly improved computational results for the complex turbulent boundary layer flows, such as the wall jet flow and the wake boundary layer interaction flow, compared with available computational results obtained by using the standard kappa-epsilon turbulence model.

  2. A multiple-time-scale turbulence model based on variable partitioning of the turbulent kinetic energy spectrum

    NASA Technical Reports Server (NTRS)

    Kim, S.-W.; Chen, C.-P.

    1989-01-01

    A multiple-time-scale turbulence model of a single point closure and a simplified split-spectrum method is presented. In the model, the effect of the ratio of the production rate to the dissipation rate on eddy viscosity is modeled by use of the multiple-time-scales and a variable partitioning of the turbulent kinetic energy spectrum. The concept of a variable partitioning of the turbulent kinetic energy spectrum and the rest of the model details are based on the previously reported algebraic stress turbulence model. Example problems considered include: a fully developed channel flow, a plane jet exhausting into a moving stream, a wall jet flow, and a weakly coupled wake-boundary layer interaction flow. The computational results compared favorably with those obtained by using the algebraic stress turbulence model as well as experimental data. The present turbulence model, as well as the algebraic stress turbulence model, yielded significantly improved computational results for the complex turbulent boundary layer flows, such as the wall jet flow and the wake boundary layer interaction flow, compared with available computational results obtained by using the standard kappa-epsilon turbulence model.

  3. Distortion in the β-decay spectrum for low electron kinetic energies

    NASA Astrophysics Data System (ADS)

    Eman, B.; Tadić, D.

    1986-06-01

    The observed distortion in the β-decay spectrum of tritium might be reduced by somewhat weaker screening corrections than those used by Simpson. Such weaker corrections seem to be strongly indicated by atomic structure calculations. Other corrections to the Kurie plot are also discussed.

  4. The determination of neutron energy spectrum in reactor core C1 of reactor VR-1 Sparrow

    SciTech Connect

    Vins, M.

    2008-07-15

    This contribution overviews neutron spectrum measurement, which was done on training reactor VR-1 Sparrow with a new nuclear fuel. Former nuclear fuel IRT-3M was changed for current nuclear fuel IRT-4M with lower enrichment of 235U (enrichment was reduced from former 36% to 20%) in terms of Reduced Enrichment for Research and Test Reactors (RERTR) Program. Neutron spectrum measurement was obtained by irradiation of activation foils at the end of pipe of rabit system and consecutive deconvolution of obtained saturated activities. Deconvolution was performed by computer iterative code SAND-II with 620 groups' structure. All gamma measurements were performed on Canberra HPGe. Activation foils were chosen according physical and nuclear parameters from the set of certificated foils. The Resulting differential flux at the end of pipe of rabit system agreed well with typical spectrum of light water reactor. Measurement of neutron spectrum has brought better knowledge about new reactor core C1 and improved methodology of activation measurement. (author)

  5. Energy-Based Analysis of Mechanisms of Earthquake-Induced Landslide Using Hilbert-Huang Transform and Marginal Spectrum

    NASA Astrophysics Data System (ADS)

    Fan, Gang; Zhang, Li-Min; Zhang, Jian-Jing; Ouyang, Fang

    2017-09-01

    Based on the Hilbert-Huang Transform and its marginal spectrum, an energy-based method is proposed to analyse the dynamics of earthquake-induced landslides and a case study is presented to illustrate the proposed method. The results show that the seismic Hilbert energy in the sliding mass of a landslide is larger than that in the sliding bed when subjected to seismic excitations, causing different dynamic responses between the sliding mass and the sliding bed. The seismic Hilbert energy transits from the high-frequency components to the low-frequency components when the seismic waves propagate through the weak zone, causing a nonuniform seismic Hilbert energy distribution in the frequency domain. Shear failure develops first at the crest and toe of the sliding mass due to resonance effects. Meanwhile, the seismic Hilbert energy in the frequency components of 3-5 Hz, which is close to the natural frequency of the slope, is largely dissipated in the initiation and failure processes of the landslide. With the development of dynamic failure, the peak energy transmission ratios in the weak zone decrease gradually. This study offers an energy-based interpretation for the initiation and progression of earthquake-induced landslides with the shattering-sliding failure type.

  6. Development of a "First Principles" Water Potential with Flexible Monomers: Dimer Potential Energy Surface, VRT Spectrum, and Second Virial Coefficient.

    PubMed

    Babin, Volodymyr; Leforestier, Claude; Paesani, Francesco

    2013-12-10

    The development of a "first principles" water potential with flexible monomers (MB-pol) for molecular simulations of water systems from gas to condensed phases is described. MB-pol is built upon the many-body expansion of the intermolecular interactions, and the specific focus of this study is on the two-body term (V2B) representing the full-dimensional intermolecular part of the water dimer potential energy surface. V2B is constructed by fitting 40,000 dimer energies calculated at the CCSD(T)/CBS level of theory and imposing the correct asymptotic behavior at long-range as predicted from "first principles". The comparison of the calculated vibration-rotation tunneling (VRT) spectrum and second virial coefficient with the corresponding experimental results demonstrates the accuracy of the MB-pol dimer potential energy surface.

  7. The Cosmic Ray spectrum in the energy region between 1012 and 1016 eV measured by ARGO-YBJ

    NASA Astrophysics Data System (ADS)

    Montini, Paolo

    2017-03-01

    The ARGO-YBJ experiment has been in full and stable data taking at the Yangbajing cosmic ray observatory (Tibet, P.R. China, 4300 m a.s.l.) for more than five years. The detector has been designed in order to explore the Cosmic Ray (CR) spectrum in an energy range from few TeV up to several PeV. The high segmentation of the detector allows a detailed measurement of the lateral particle distribution which can be exploited on order to identify showers produced by primaries of different mass. The results of the measurement of the all-particle and proton plus helium energy spectra in the energy region between 1012 and 1016 eV are discussed.

  8. The 9Be(d,n) 10B-reaction as intense neutron source with continuous energy spectrum

    NASA Astrophysics Data System (ADS)

    Baumann, F. M.; Domogala, G.; Freiesleben, H.; Paul, H. J.; Puhlvers, S.; Sohlbach, H.

    1986-06-01

    Neutron energy spectra produced by deuterons of 3 to 8 MeV in a thick 9Be-target were measured at various scattering angles. Significant angle dependences were observed. Angular distributions of the most energetic neutrons produced in thin 9Be targets can be described quantitatively in DWBA, which is an indication for a direct reaction mechanism. As a consequence all but 0°-neutrons are polarized to a certain extent. Also presented is the neutron energy spectrum of 7Li(d,n) 8Be at 0° produced in a thick 7Li-target. The potential of these intense 0°-neutron beams with continuous energy distributions is demonstrated by a measurement of the neutron absorption cross section of natural carbon.

  9. Large Eddy Simulations Analysis of the Energy Spectrum Without Mutual Friction in Superfluid 4 He: HVBK Model

    NASA Astrophysics Data System (ADS)

    Bakhtaoui, M.; Merahi, L.

    2017-01-01

    The reliability of the filtered on the Hall-Vinen-Bekarevich-Khalatnikov (HVBK) model without mutual friction force is now investigated via some large eddy simulations of freely decaying isotropic superfluid turbulence. The filtered HVBK model is solved using a fully pseudo-spectral method, which is an extension of the classical Rogallo's method to the two-fluid model. Furthermore, in this paper, we analyze the evolution of various terms constituting the HVBK momentum equations using the balance equation for the energy-spectrum function. Our results are presented in both cases with and without mutual friction force. LES predictions have shown that this mutual friction decreases the energy dissipation of the normal part and the energy transfer is more significant when this force is taken into account.

  10. MULTIMODE quantum calculations of vibrational energies and IR spectrum of the NO{sup +}(H{sub 2}O) cluster using accurate potential energy and dipole moment surfaces

    SciTech Connect

    Homayoon, Zahra

    2014-09-28

    A new, full (nine)-dimensional potential energy surface and dipole moment surface to describe the NO{sup +}(H{sub 2}O) cluster is reported. The PES is based on fitting of roughly 32 000 CCSD(T)-F12/aug-cc-pVTZ electronic energies. The surface is a linear least-squares fit using a permutationally invariant basis with Morse-type variables. The PES is used in a Diffusion Monte Carlo study of the zero-point energy and wavefunction of the NO{sup +}(H{sub 2}O) and NO{sup +}(D{sub 2}O) complexes. Using the calculated ZPE the dissociation energies of the clusters are reported. Vibrational configuration interaction calculations of NO{sup +}(H{sub 2}O) and NO{sup +}(D{sub 2}O) using the MULTIMODE program are performed. The fundamental, a number of overtone, and combination states of the clusters are reported. The IR spectrum of the NO{sup +}(H{sub 2}O) cluster is calculated using 4, 5, 7, and 8 modes VSCF/CI calculations. The anharmonic, coupled vibrational calculations, and IR spectrum show very good agreement with experiment. Mode coupling of the water “antisymmetric” stretching mode with the low-frequency intermolecular modes results in intensity borrowing.

  11. Chiropractic Adjustment

    MedlinePlus

    ... t seek chiropractic adjustment if you have: Severe osteoporosis Numbness, tingling or loss of strength in an ... treated. Chiropractic adjustment can be effective in treating low back pain, although much of the research done shows only ...

  12. High-efficiency solar energy conversion with spectrum splitting prismatic lens (and other configurations)

    NASA Astrophysics Data System (ADS)

    Apostoleris, Harry; Maragliano, Carlo; Chiesa, Matteo; Stefancich, Marco

    2016-09-01

    Optical spectrum splitting systems that divide light between independent solar cells of different band gaps have received increasing attention in recent years as an alternative to expensive multijunction cells for high-efficiency PV. Most research, however, has focused on dichroic filters and other photonic structures that are expensive to manufacture. This has the effect of transferring the cost of the system from the PV cells to the optics. As a low-cost spectrum splitting approach we designed a prismatic lens that simultaneously splits and concentrates light and can be fabricated by injection molding. We present experimental results of a two-cell demonstration system, and calculations for low-cost configurations of commercial solar cells, enabled by the removal of lattice-matching requirements.

  13. A multiple-time-scale turbulence model based on variable partitioning of turbulent kinetic energy spectrum

    NASA Technical Reports Server (NTRS)

    Kim, S.-W.; Chen, C.-P.

    1988-01-01

    The paper presents a multiple-time-scale turbulence model of a single point closure and a simplified split-spectrum method. Consideration is given to a class of turbulent boundary layer flows and of separated and/or swirling elliptic turbulent flows. For the separated and/or swirling turbulent flows, the present turbulence model yielded significantly improved computational results over those obtained with the standard k-epsilon turbulence model.

  14. A multiple-time-scale turbulence model based on variable partitioning of turbulent kinetic energy spectrum

    NASA Technical Reports Server (NTRS)

    Kim, S.-W.; Chen, C.-P.

    1988-01-01

    The paper presents a multiple-time-scale turbulence model of a single point closure and a simplified split-spectrum method. Consideration is given to a class of turbulent boundary layer flows and of separated and/or swirling elliptic turbulent flows. For the separated and/or swirling turbulent flows, the present turbulence model yielded significantly improved computational results over those obtained with the standard k-epsilon turbulence model.

  15. Time-dependent density functional study of the electronic potential energy curves and excitation spectrum of the oxygen molecule.

    PubMed

    Guan, Jingang; Wang, Fan; Ziegler, Tom; Cox, Hazel

    2006-07-28

    Orbital energies, ionization potentials, molecular constants, potential energy curves, and the excitation spectrum of O(2) are calculated using time-dependent density functional theory (TDDFT) with Tamm-Dancoff approximation (TDA). The calculated negative highest occupied molecular orbital energy (-epsilon(HOMO)) is compared with the energy difference ionization potential for five exchange correlation functionals consisting of the local density approximation (LDAxc), gradient corrected Becke exchange plus Perdew correlation (B(88X)+P(86C)), gradient regulated asymptotic correction (GRAC), statistical average of orbital potentials (SAOP), and van Leeuwen and Baerends asymptotically correct potential (LB94). The potential energy curves calculated using TDDFT with the TDA at internuclear distances from 1.0 to 1.8 A are divided into three groups according to the electron configurations. The 1pi(u) (4)1pi(g) (2) electron configuration gives rise to the X (3)Sigma(g) (-), a (1)Delta(g), and b (1)Sigma(g) (+) states; the 1pi(u) (3)1pi(g) (3) electron configuration gives rise to the c (1)Sigma(u) (-), C (3)Delta(u), and A (3)Sigma(u) (+) states; and the B (3)Sigma(u) (-), A (1)Delta(u), and f (1)Sigma(u) (+) states are determined by the mixing of two or more electron configurations. The excitation spectrum of the oxygen molecule, calculated with the aforementioned exchange correlation functionals, shows that the results are quite sensitive to the choice of functional. The LDAxc and the B(88X)+P(86C) functionals produce similar spectroscopic patterns with a single strongly absorbing band positioned at 19.82 and 19.72 eV, respectively, while the asymptotically corrected exchange correlation functionals of the SAOP and the LB94 varieties yield similar excitation spectra where the computed strongly absorbing band is located at 16.09 and 16.42 eV, respectively. However, all of the exchange correlation functionals yield only one strongly absorbing band (oscillator strength

  16. Upgrades of DARWIN, a dose and spectrum monitoring system applicable to various types of radiation over wide energy ranges

    NASA Astrophysics Data System (ADS)

    Sato, Tatsuhiko; Satoh, Daiki; Endo, Akira; Shigyo, Nobuhiro; Watanabe, Fusao; Sakurai, Hiroki; Arai, Yoichi

    2011-05-01

    A dose and spectrum monitoring system applicable to neutrons, photons and muons over wide ranges of energy, designated as DARWIN, has been developed for radiological protection in high-energy accelerator facilities. DARWIN consists of a phoswitch-type scintillation detector, a data-acquisition (DAQ) module for digital waveform analysis, and a personal computer equipped with a graphical-user-interface (GUI) program for controlling the system. The system was recently upgraded by introducing an original DAQ module based on a field programmable gate array, FPGA, and also by adding a function for estimating neutron and photon spectra based on an unfolding technique without requiring any specific scientific background of the user. The performance of the upgraded DARWIN was examined in various radiation fields, including an operational field in J-PARC. The experiments revealed that the dose rates and spectra measured by the upgraded DARWIN are quite reasonable, even in radiation fields with peak structures in terms of both spectrum and time variation. These results clearly demonstrate the usefulness of DARWIN for improving radiation safety in high-energy accelerator facilities.

  17. Solar modulation of the deep space galactic cosmic ray lineal energy spectrum measured by CRaTER, 2009-2014

    NASA Astrophysics Data System (ADS)

    Zeitlin, C.; Case, A. W.; Schwadron, N. A.; Spence, H. E.; Mazur, J. E.; Joyce, C. J.; Looper, M. D.; Jordan, A.; Rios, R. R.; Townsend, L. W.; Kasper, J. C.; Blake, J. B.; Smith, S.; Wilson, J.; Iwata, Y.

    2016-03-01

    The Cosmic Ray Telescope for the Effects of Radiation (CRaTER) is an energetic particle detector flying aboard the Lunar Reconnaissance Orbiter. Since arriving at the Moon in 2009, CRaTER has observed the deep solar minimum of solar cycle 23, the ascending phase of cycle 24, the very weak maximum of cycle 24, and in recent months, what appears to be the start of the descending phase of cycle 24. In earlier work, we presented lineal energy spectra of galactic cosmic rays (GCRs) at solar minimum for different shielding depths. The long period of CRaTER observations allows us to study the evolution of these spectra as a function of solar modulation. As solar modulation increases, the total flux of GCRs decreases, and lower-energy ions are preferentially removed from the spectrum of ions that arrive in the inner heliosphere. These effects lead to modest variations in the lineal energy spectrum as a function of time. GCR fluxes at the 2009/2010 solar minimum were high by historical standards and at solar maximum remained high compared to earlier maxima.

  18. Measurements of the neutron dose and energy spectrum on the International Space Station during expeditions ISS-16 to ISS-21.

    PubMed

    Smith, M B; Akatov, Yu; Andrews, H R; Arkhangelsky, V; Chernykh, I V; Ing, H; Khoshooniy, N; Lewis, B J; Machrafi, R; Nikolaev, I; Romanenko, R Y; Shurshakov, V; Thirsk, R B; Tomi, L

    2013-01-01

    As part of the international Matroshka-R and Radi-N experiments, bubble detectors have been used on board the ISS in order to characterise the neutron dose and the energy spectrum of neutrons. Experiments using bubble dosemeters inside a tissue-equivalent phantom were performed during the ISS-16, ISS-18 and ISS-19 expeditions. During the ISS-20 and ISS-21 missions, the bubble dosemeters were supplemented by a bubble-detector spectrometer, a set of six detectors that was used to determine the neutron energy spectrum at various locations inside the ISS. The temperature-compensated spectrometer set used is the first to be developed specifically for space applications and its development is described in this paper. Results of the dose measurements indicate that the dose received at two different depths inside the phantom is not significantly different, suggesting that bubble detectors worn by a person provide an accurate reading of the dose received inside the body. The energy spectra measured using the spectrometer are in good agreement with previous measurements and do not show a strong dependence on the precise location inside the station. To aid the understanding of the bubble-detector response to charged particles in the space environment, calculations have been performed using a Monte-Carlo code, together with data collected on the ISS. These calculations indicate that charged particles contribute <2% to the bubble count on the ISS, and can therefore be considered as negligible for bubble-detector measurements in space.

  19. Measurement of the energy spectrum of cosmic-ray induced neutrons aboard an ER-2 high-altitude airplane.

    PubMed

    Goldhagen, P; Reginatto, M; Kniss, T; Wilson, J W; Singleterry, R C; Jones, I W; Van Steveninck, W

    2002-01-01

    Crews working on present-day jet aircraft are a large occupationally exposed group with a relatively high average effective dose from galactic cosmic radiation. Crews of future high-speed commercial aircraft flying at higher altitudes would be even more exposed. To help reduce the significant uncertainties in calculations of such exposures, the atmospheric ionizing radiation (AIR) project, an international collaboration of 15 laboratories, made simultaneous radiation measurements with 14 instruments on five flights of a NASA ER-2 high-altitude aircraft. The primary AIR instrument was a highly sensitive extended-energy multisphere neutron spectrometer with lead and steel shells placed within the moderators of two of its 14 detectors to enhance response at high energies. Detector responses were calculated for neutrons and charged hadrons at energies up to 100 GeV using MCNPX. Neutron spectra were unfolded from the measured count rates using the new MAXED code. We have measured the cosmic-ray neutron spectrum (thermal to >10 GeV), total neutron fluence rate, and neutron effective dose and dose equivalent rates and their dependence on altitude and geomagnetic cutoff. The measured cosmic-ray neutron spectra have almost no thermal neutrons, a large "evaporation" peak near 1 MeV and a second broad peak near 100 MeV which contributes about 69% of the neutron effective dose. At high altitude, geomagnetic latitude has very little effect on the shape of the spectrum, but it is the dominant variable affecting neutron fluence rate, which was eight times higher at the northernmost measurement location than it was at the southernmost. The shape of the spectrum varied only slightly with altitude from 21 km down to 12 km (56-201 g cm-2 atmospheric depth), but was significantly different on the ground. In all cases, ambient dose equivalent was greater than effective dose for cosmic-ray neutrons.

  20. Measurement of the cosmic-ray energy spectrum above 1016 eV with the LOFAR Radboud Air Shower Array

    NASA Astrophysics Data System (ADS)

    Thoudam, S.; Buitink, S.; Corstanje, A.; Enriquez, J. E.; Falcke, H.; Hörandel, J. R.; Nelles, A.; Rachen, J. P.; Rossetto, L.; Schellart, P.; Scholten, O.; ter Veen, S.; Trinh, T. N. G.; van Kessel, L.

    2016-01-01

    The energy reconstruction of extensive air showers measured with the LOFAR Radboud Air Shower Array (LORA) is presented in detail. LORA is a particle detector array located in the center of the LOFAR radio telescope in the Netherlands. The aim of this work is to provide an accurate and independent energy measurement for the air showers measured through their radio signal with the LOFAR antennas. The energy reconstruction is performed using a parameterized relation between the measured shower size and the cosmic-ray energy obtained from air shower simulations. In order to illustrate the capabilities of LORA, the all-particle cosmic-ray energy spectrum has been reconstructed, assuming that cosmic rays are composed only of protons or iron nuclei in the energy range between ∼2 × 1016 and 2 × 1018 eV. The results are compatible with literature values and a changing mass composition in the transition region from a Galactic to an extragalactic origin of cosmic rays.

  1. High-energy properties of the high-redshift flat spectrum radio quasar PKS 2149-306

    NASA Astrophysics Data System (ADS)

    D'Ammando, F.; Orienti, M.

    2016-01-01

    We investigate the γ-ray and X-ray properties of the flat spectrum radio quasar PKS 2149-306 at redshift z = 2.345. A strong γ-ray flare from this source was detected by the Large Area Telescope on board the Fermi Gamma-ray Space Telescope satellite in 2013 January, reaching on January 20 a daily peak flux of (301 ± 36) × 10-8 ph cm-2 s-1 in the 0.1-100 GeV energy range. This flux corresponds to an apparent isotropic luminosity of (1.5 ± 0.2) × 1050 erg s-1, comparable to the highest values observed by a blazar so far. During the flare the increase of flux was accompanied by a significant change of the spectral properties. Moreover significant flux variations on a 6-h time-scale were observed, compatible with the light crossing time of the event horizon of the central black hole. The broad-band X-ray spectra of PKS 2149-306 observed by Swift-XRT and NuSTAR are well described by a broken power-law model, with a very hard spectrum (Γ1 ˜ 1) below the break energy, at E break = 2.5-3.0 keV, and Γ2 ˜ 1.4-1.5 above the break energy. The steepening of the spectrum below ˜3 keV may indicate that the soft X-ray emission is produced by the low-energy relativistic electrons. This is in agreement with the small variability amplitude and the lack of spectral changes in that part of the X-ray spectrum observed between the two NuSTAR and Swift joint observations. As for the other high-redshift FSRQ detected by both Fermi-LAT and Swift-BAT, the photon index of PKS 2149-306 in hard X-ray is 1.6 or lower and the average γ-ray luminosity higher than 2 × 1048 erg s-1.

  2. Separation of coexisting dynamical regimes in multistate intermittency based on wavelet spectrum energies in an erbium-doped fiber laser.

    PubMed

    Hramov, Alexander E; Koronovskii, Alexey A; Moskalenko, Olga I; Zhuravlev, Maksim O; Jaimes-Reategui, Rider; Pisarchik, Alexander N

    2016-05-01

    We propose a method for the detection and localization of different types of coexisting oscillatory regimes that alternate with each other leading to multistate intermittency. Our approach is based on consideration of wavelet spectrum energies. The proposed technique is tested in an erbium-doped fiber laser with four coexisting periodic orbits, where external noise induces intermittent switches between the coexisting states. Statistical characteristics of multistate intermittency, such as the mean duration of the phases for every oscillation type, are examined with the help of the developed method. We demonstrate strong advantages of the proposed technique over previously used amplitude methods.

  3. Wide-spectrum energy harvesting out of colored Lévy-like fluctuations, by monostable piezoelectric transducers

    NASA Astrophysics Data System (ADS)

    Deza, J. Ignacio; Deza, Roberto R.; Wio, Horacio S.

    2012-11-01

    This work aims to optimize the overall performance of a model oscillator, as an energy harvester of Lévy-like mesoscopic fluctuations through piezoelectric conversion. As a further step in the description of a realistic harvesting device we consider a monostable Woods-Saxon oscillator, which can interpolate between square well and harmonic-like behaviors. We study the interplay between the potential shape and the noise's spectrum and statistics. The dependence of the power output on the parameters determining those features indicates the directions in which the former can be increased.

  4. High-energy properties of the high-redshift flat spectrum radio quasar PKS 2149-306

    SciTech Connect

    D'Ammando, F.; Orienti, M.

    2015-11-19

    We investigate the γ-ray and X-ray properties of the flat spectrum radio quasar PKS 2149-306 at redshift z = 2.345. A strong γ-ray flare from this source was detected by the Large Area Telescope on board the Fermi Gamma-ray Space Telescope satellite in 2013 January, reaching on January 20 a daily peak flux of (301 ± 36)×10-8 ph cm-2 s-1 in the 0.1–100 GeV energy range. This flux corresponds to an apparent isotropic luminosity of (1.5±0.2)×1050 erg s-1, comparable to the highest values observed by a blazar so far. During the flare the increase of flux was accompanied by a significant change of the spectral properties. Moreover significant flux variations on a 6-h time- scale were observed, compatible with the light crossing time of the event horizon of the central black hole. The broad band X-ray spectra of PKS 2149-306 observed by Swift-XRT and NuSTAR are well described by a broken power-law model, with a very hard spectrum1 ~1) below the break energy, at Ebreak = 2.5–3.0 keV, and Γ2 ~ 1.4–1.5 above the break energy. The steepening of the spectrum below ~3 keV may indicate that the soft X- ray emission is produced by the low-energy relativistic electrons. This is in agreement with the small variability amplitude and the lack of spectral changes in that part of the X-ray spectrum observed between the two NuSTAR and Swift joint observations. As for the other high-redshift FSRQ detected by both Fermi-LAT and Swift-BAT, the photon index of PKS 2149-306 in hard X-ray is 1.6 or lower and the average γ-ray luminosity higher than 2×1048 erg s-1.

  5. High-energy properties of the high-redshift flat spectrum radio quasar PKS 2149-306

    DOE PAGES

    D'Ammando, F.; Orienti, M.

    2015-11-19

    We investigate the γ-ray and X-ray properties of the flat spectrum radio quasar PKS 2149-306 at redshift z = 2.345. A strong γ-ray flare from this source was detected by the Large Area Telescope on board the Fermi Gamma-ray Space Telescope satellite in 2013 January, reaching on January 20 a daily peak flux of (301 ± 36)×10-8 ph cm-2 s-1 in the 0.1–100 GeV energy range. This flux corresponds to an apparent isotropic luminosity of (1.5±0.2)×1050 erg s-1, comparable to the highest values observed by a blazar so far. During the flare the increase of flux was accompanied by amore » significant change of the spectral properties. Moreover significant flux variations on a 6-h time- scale were observed, compatible with the light crossing time of the event horizon of the central black hole. The broad band X-ray spectra of PKS 2149-306 observed by Swift-XRT and NuSTAR are well described by a broken power-law model, with a very hard spectrum (Γ1 ~1) below the break energy, at Ebreak = 2.5–3.0 keV, and Γ2 ~ 1.4–1.5 above the break energy. The steepening of the spectrum below ~3 keV may indicate that the soft X- ray emission is produced by the low-energy relativistic electrons. This is in agreement with the small variability amplitude and the lack of spectral changes in that part of the X-ray spectrum observed between the two NuSTAR and Swift joint observations. As for the other high-redshift FSRQ detected by both Fermi-LAT and Swift-BAT, the photon index of PKS 2149-306 in hard X-ray is 1.6 or lower and the average γ-ray luminosity higher than 2×1048 erg s-1.« less

  6. Autism spectrum disorder, flea and tick medication, and adjustments for exposure misclassification: the CHARGE (CHildhood Autism Risks from Genetics and Environment) case–control study

    PubMed Central

    2014-01-01

    Background The environmental contribution to autism spectrum disorders (ASD) is largely unknown, but household pesticides are receiving increased attention. We examined associations between ASD and maternally-reported use of imidacloprid, a common flea and tick treatment for pets. Methods Bayesian logistic models were used to estimate the association between ASD and imidacloprid and to correct for potential differential exposure misclassification due to recall in a case control study of ASD. Results Our analytic dataset included complete information for 262 typically developing controls and 407 children with ASD. Compared with exposure among controls, the odds of prenatal imidacloprid exposure among children with ASD were slightly higher, with an odds ratio (OR) of 1.3 (95% Credible Interval [CrI] 0.78, 2.2). A susceptibility window analysis yielded higher ORs for exposures during pregnancy than for early life exposures, whereas limiting to frequent users of imidacloprid, the OR increased to 2.0 (95% CI 1.0, 3.9). Conclusions Within plausible estimates of sensitivity and specificity, the association could result from exposure misclassification alone. The association between imidacloprid exposure and ASD warrants further investigation, and this work highlights the need for validation studies regarding prenatal exposures in ASD. PMID:24456651

  7. Measurement of vibrational spectrum of liquid using monochromated scanning transmission electron microscopy-electron energy loss spectroscopy.

    PubMed

    Miyata, Tomohiro; Fukuyama, Mao; Hibara, Akihide; Okunishi, Eiji; Mukai, Masaki; Mizoguchi, Teruyasu

    2014-10-01

    Investigations on the dynamic behavior of molecules in liquids at high spatial resolution are greatly desired because localized regions, such as solid-liquid interfaces or sites of reacting molecules, have assumed increasing importance with respect to improving material performance. In application to liquids, electron energy loss spectroscopy (EELS) observed with transmission electron microscopy (TEM) is a promising analytical technique with the appropriate resolutions. In this study, we obtained EELS spectra from an ionic liquid, 1-ethyl-3-methylimidazolium bis (trifluoromethyl-sulfonyl) imide (C2mim-TFSI), chosen as the sampled liquid, using monochromated scanning TEM (STEM). The molecular vibrational spectrum and the highest occupied molecular orbital (HOMO)-lowest unoccupied molecular orbital (LUMO) gap of the liquid were investigated. The HOMO-LUMO gap measurement coincided with that obtained from the ultraviolet-visible spectrum. A shoulder in the spectrum observed ∼0.4 eV is believed to originate from the molecular vibration. From a separately performed infrared observation and first-principles calculations, we found that this shoulder coincided with the vibrational peak attributed to the C-H stretching vibration of the [C2mim(+)] cation. This study demonstrates that a vibrational peak for a liquid can be observed using monochromated STEM-EELS, and leads one to expect observations of chemical reactions or aids in the analysis of the dynamic behavior of molecules in liquid.

  8. Time-Dependent Spatial Domains of Electrons Accross the Energy Spectrum

    NASA Astrophysics Data System (ADS)

    Reeves, G. D.; Denton, M.; Boyd, A. J.; Turner, D. L.; Claudepierre, S. G.; Fennell, J. F.; Jaynes, A. N.; Kanekal, S. G.; Baker, D. N.; Mauk, B.; Spence, H. E.

    2016-12-01

    Radiation belt electrons in the inner magnetosphere are commonly described by an inner belt population close to the Earth, inside the plasmasphere, and an outer belt population outside the plasmasphere, separated by a "slot region". This picture has influenced much of our interpretation of radiation belt events and has informed much of our understanding of the processes that control radiation belt structure and dynamics. Recent studies with Van Allen Probes, MMS, THEMIS, and other HSO data sets have added much nuance and richness to that simplistic picture. One of the first results from the Van Allen Probes mission [Baker et al., 2013] showed that the outer zone can, at times, consist of two distinct belts (two spatial domains) at some energies while different energies still populate a single belt. Fennell et al., [2015] and Li et al., [2015] showed that, during the Van Allen Probes era there were no inner zone electrons with energies >1 MeV. In addition, Reeves et al., [2016] showed that the spatial extent of the inner zone was strongly energy-dependent with low energies (e.g. 50 keV) extending from L = 1 to 4 but high energies (e.g. 800 keV) extending L = 1 to only L 1.2. At high energies (e.g. >3 MeV) Baker et al., [2014] described an "impenetrable barrier" that restricted outer zone electrons to L >2.8 while Reeves et al., [2016] showed that electrons at lower energies commonly penetrated through the slot region and into the inner zone. Additionally, even when electrons did not penetrate through the slot, lower energies penetrated more deeply with a strikingly linear relationship between log(Energy) and L of the inner edge of the outer belt. Therefore, although the inner edge of the radiation belts may be at the plasmapause for one energy they cannot be co-located at other energies. We will discuss how and why electrons at different energies occupy different spatial domains as well as how and why those domains change in time. Among the features to be

  9. The Determination of the Spectrum Energy on the model of DNA-protein interactions using WKB approximation method

    NASA Astrophysics Data System (ADS)

    Syahroni, Edy; Suparmi, A.; Cari, C.

    2017-01-01

    The spectrum energy’s equation for Killingback potential on the model of DNA and protein interactions was obtained using WKB approximation method. The Killingbeck potential was substituted into the general equation of WKB approximation method to determine the energy. The general equation required the value of critical turning point to complete the form equation. In this research, the general form of Killingbeck potential was causing the equation of critical turning point turn into cube equation. In this case we take the value of critical turning point only with the real value. In mathematical condition, it was satisfied with requirement Discriminant was less than or equal to 0. If D=0, it would give two values of critical turning point and if D<0, it would give three values of critical turning point. In this research we present both of those requirements to complete the general Equation of Energy.

  10. Measurement of the atmospheric muon neutrino energy spectrum with IceCube in the 79- and 86-String configuration

    NASA Astrophysics Data System (ADS)

    Ruhe, T.; Scheriau, F.; Schmitz, M.

    2016-04-01

    IceCube is a neutrino telescope with an instrumented volume of one cubic kilometer. A total of 5160 Digital Optical Modules (DOMs) is deployed on 86 strings forming a three dimensional detector array. Although primarily designed for the detection of neutrinos from astrophysical sources, the detector can be used for spectral measurements of atmospheric neutrinos. These spectral measurements are hindered by a dominant background of atmospheric muons. State-of-the-art techniques from Machine Learning and Data Mining are required to select a high-purity sample of atmospheric neutrino candidates. The energy spectrum of muon neutrinos is obtained from energy-dependent input variables by utilizing regularized unfolding. The results obtained using IceCube in the 79- and 86-string configuration are presented in this paper.

  11. Measurements of High Energy Neutron Spectrum (> 10 MeV) by Using Yttrium Foils in a U/Pb Assembly

    NASA Astrophysics Data System (ADS)

    Bielewicz, M.; Strugalska-Gola, E.; Szuta, M.; Wojciechowski, A.; Kadykov, M.; Tyutyunnikov, S.

    2014-05-01

    Study of deep subcritical electronuclear systems and radioactive waste transmutation using relativistic beams were performed. This work is a preliminary step toward the study of the physical properties of Accelerator Driven Systems, in which a deeply subcritical active core is irradiated by a pulsed beam of relativistic ions. The long-range goal of the project is to study the capabilities of such systems with a hard neutron spectrum, for transmutation of radioactive nuclear wastes. Two experimental assemblies, “Energy plus Transmutation” (2006-2009) and “Quinta” (2011-), were irradiated by 1 to 6 GeV deuteron beams using the JINR NUCLOTRON accelerator. The main difference between the two experimental setups is the spallation target - lead or natural uranium. We attempt to obtain neutron energy spectra inside the volume of these assemblies using threshold reactions in natural yttrium (89Y) foils. Some results from three different experiments are presented.

  12. Broad energy range neutron spectroscopy using a liquid scintillator and a proportional counter: Application to a neutron spectrum similar to that from an improvised nuclear device

    NASA Astrophysics Data System (ADS)

    Xu, Yanping; Randers-Pehrson, Gerhard; Marino, Stephen A.; Garty, Guy; Harken, Andrew; Brenner, David J.

    2015-09-01

    A novel neutron irradiation facility at the Radiological Research Accelerator Facility (RARAF) has been developed to mimic the neutron radiation from an Improvised Nuclear Device (IND) at relevant distances (e.g. 1.5 km) from the epicenter. The neutron spectrum of this IND-like neutron irradiator was designed according to estimations of the Hiroshima neutron spectrum at 1.5 km. It is significantly different from a standard reactor fission spectrum, because the spectrum changes as the neutrons are transported through air, and it is dominated by neutron energies from 100 keV up to 9 MeV. To verify such wide energy range neutron spectrum, detailed here is the development of a combined spectroscopy system. Both a liquid scintillator detector and a gas proportional counter were used for the recoil spectra measurements, with the individual response functions estimated from a series of Monte Carlo simulations. These normalized individual response functions were formed into a single response matrix for the unfolding process. Several accelerator-based quasi-monoenergetic neutron source spectra were measured and unfolded to test this spectroscopy system. These reference neutrons were produced from two reactions: T(p,n)3He and D(d,n)3He, generating neutron energies in the range between 0.2 and 8 MeV. The unfolded quasi-monoenergetic neutron spectra indicated that the detection system can provide good neutron spectroscopy results in this energy range. A broad-energy neutron spectrum from the 9Be(d,n) reaction using a 5 MeV deuteron beam, measured at 60 degrees to the incident beam was measured and unfolded with the evaluated response matrix. The unfolded broad neutron spectrum is comparable with published time-of-flight results. Finally, the pair of detectors were used to measure the neutron spectrum generated at the RARAF IND-like neutron facility and a comparison is made to the neutron spectrum of Hiroshima.

  13. Broad Energy Range Neutron Spectroscopy using a Liquid Scintillator and a Proportional Counter: Application to a Neutron Spectrum Similar to that from an Improvised Nuclear Device

    PubMed Central

    Randers-Pehrson, Gerhard; Marino, Stephen A.; Garty, Guy; Harken, Andrew; Brenner, David J.

    2015-01-01

    A novel neutron irradiation facility at the Radiological Research Accelerator Facility (RARAF) has been developed to mimic the neutron radiation from an Improvised Nuclear Device (IND) at relevant distances (e.g. 1.5 km) from the epicenter. The neutron spectrum of this IND-like neutron irradiator was designed according to estimations of the Hiroshima neutron spectrum at 1.5 km. It is significantly different from a standard reactor fission spectrum, because the spectrum changes as the neutrons are transported through air, and it is dominated by neutron energies from 100 keV up to 9 MeV. To verify such wide energy range neutron spectrum, detailed here is the development of a combined spectroscopy system. Both a liquid scintillator detector and a gas proportional counter were used for the recoil spectra measurements, with the individual response functions estimated from a series of Monte Carlo simulations. These normalized individual response functions were formed into a single response matrix for the unfolding process. Several accelerator-based quasi-monoenergetic neutron source spectra were measured and unfolded to test this spectroscopy system. These reference neutrons were produced from two reactions: T(p,n)3He and D(d,n)3He, generating neutron energies in the range between 0.2 and 8 MeV. The unfolded quasi-monoenergetic neutron spectra indicated that the detection system can provide good neutron spectroscopy results in this energy range. A broad-energy neutron spectrum from the 9Be(d,n) reaction using a 5 MeV deuteron beam, measured at 60 degrees to the incident beam was measured and unfolded with the evaluated response matrix. The unfolded broad neutron spectrum is comparable with published time-of-flight results. Finally, the pair of detectors were used to measure the neutron spectrum generated at the RARAF IND-like neutron facility and a comparison is made to the neutron spectrum of Hiroshima. PMID:26273118

  14. Broad Energy Range Neutron Spectroscopy using a Liquid Scintillator and a Proportional Counter: Application to a Neutron Spectrum Similar to that from an Improvised Nuclear Device.

    PubMed

    Xu, Yanping; Randers-Pehrson, Gerhard; Marino, Stephen A; Garty, Guy; Harken, Andrew; Brenner, David J

    2015-09-11

    A novel neutron irradiation facility at the Radiological Research Accelerator Facility (RARAF) has been developed to mimic the neutron radiation from an Improvised Nuclear Device (IND) at relevant distances (e.g. 1.5 km) from the epicenter. The neutron spectrum of this IND-like neutron irradiator was designed according to estimations of the Hiroshima neutron spectrum at 1.5 km. It is significantly different from a standard reactor fission spectrum, because the spectrum changes as the neutrons are transported through air, and it is dominated by neutron energies from 100 keV up to 9 MeV. To verify such wide energy range neutron spectrum, detailed here is the development of a combined spectroscopy system. Both a liquid scintillator detector and a gas proportional counter were used for the recoil spectra measurements, with the individual response functions estimated from a series of Monte Carlo simulations. These normalized individual response functions were formed into a single response matrix for the unfolding process. Several accelerator-based quasi-monoenergetic neutron source spectra were measured and unfolded to test this spectroscopy system. These reference neutrons were produced from two reactions: T(p,n)(3)He and D(d,n)(3)He, generating neutron energies in the range between 0.2 and 8 MeV. The unfolded quasi-monoenergetic neutron spectra indicated that the detection system can provide good neutron spectroscopy results in this energy range. A broad-energy neutron spectrum from the (9)Be(d,n) reaction using a 5 MeV deuteron beam, measured at 60 degrees to the incident beam was measured and unfolded with the evaluated response matrix. The unfolded broad neutron spectrum is comparable with published time-of-flight results. Finally, the pair of detectors were used to measure the neutron spectrum generated at the RARAF IND-like neutron facility and a comparison is made to the neutron spectrum of Hiroshima.

  15. Evidence for variability of the hard X-ray feature in the Hercules X-1 energy spectrum

    NASA Technical Reports Server (NTRS)

    Tueller, J.; Cline, T. L.; Teegarden, B. J.; Paciesas, W. S.; Boclet, D.; Durouchoux, PH.; Hameury, J. M.; Prantzos, N.; Haymes, R. C.

    1984-01-01

    The hard X-ray spectrum of HER X-1 was measured for the first time with a high resolution (1.4 keV FWHM) germanium spectrometer. The observation was performed near the peak of the on-state in the 35 day cycle and the 1.24 pulsations were observed between the energies of 20 keV and 70 keV. The feature corresponds to an excess of 7.5 sigma over the low energy continuum. Smooth continuum models are poor fits to the entire energy range (chance probabilities of 2 percent or less). The best fit energies are 35 keV for an absorption line and 39 keV for an emission line. These are significantly lower energies than those derived from previous experiments. A direct comparison of the data with the results of the MPI/AIT group shows statistically significant variations which strongly suggest variability in the source. Previously announced in STAR as N83-37036

  16. Time-resolved energy spectrum measurement of a linear induction accelerator with the magnetic analyzer

    NASA Astrophysics Data System (ADS)

    Wang, Yuan; Jiang, Xiao-Guo; Yang, Guo-Jun; Chen, Si-Fu; Zhang, Zhuo; Wei, Tao; Li, Jin

    2015-01-01

    We recently set up a time-resolved optical beam diagnostic system. Using this system, we measured the high current electron beam energy in the accelerator under construction. This paper introduces the principle of the diagnostic system, describes the setup, and shows the results. A bending beam line was designed using an existing magnetic analyzer with a 300 mm-bending radius and a 60° bending angle at hard-edge approximation. Calculations show that the magnitude of the beam energy is about 18 MeV, and the energy spread is within 2%. Our results agree well with the initial estimates deduced from the diode voltage approach.

  17. Ion acceleration with a narrow energy spectrum by nanosecond laser-irradiation of solid target

    SciTech Connect

    Altana, C.; Lanzalone, G.; Mascali, D.; Cirrone, G. A. P.; Schillaci, F.; Tudisco, S.; Muoio, A.

    2016-02-15

    In laser-driven plasma, ion acceleration of aluminum with the production of a quasi-monoenergetic beam has occurred. A useful device to analyze the ions is the Thomson parabolas spectrometer, a well-known diagnostic that is able to obtain information on charge-to-mass ratio and energy distribution of the charged particles. At the LENS (Laser Energy for Nuclear Science) laboratory of INFN-LNS in Catania, experimental measures were carried out; the features of LENS are: Q-switched Nd:YAG laser with 2 J laser energy, 1064 nm fundamental wavelengths, and 6 ns pulse duration.

  18. Particle reflection and its energy spectrum from solid surfaces with adsorbate atoms

    NASA Astrophysics Data System (ADS)

    Yamamura, Y.

    1988-06-01

    Using the ACAT and ACOCT codes, the particle reflection coefficients and energy spectra reflected from solid surfaces covered with adsorbated atoms have been calculated in the low-energy region. It is found that the particle reflection coefficients of low energy ions are much reduced due to the collision between an incoming ion and an adsorbate atom, especially for M1 > M3 ( M1 and M3 being the atomic masses of an ion and an adsorbate atom, respectively), and the surface peak from a substrate atom becomes strongly suppressed as the coverage increases.

  19. Laser diagnostics of the energy spectrum of Rydberg states of the lithium-7 atom

    SciTech Connect

    Zelener, B. B. Saakyan, S. A.; Sautenkov, V. A.; Manykin, E. A.; Zelener, B. V.; Fortov, V. E.

    2015-12-15

    The spectra of excited lithium-7 atoms prepared in a magneto-optical trap are studied using a UV laser. The laser diagnostics of the energy of Rydberg atoms is developed based on measurements of the change in resonance fluorescence intensity of ultracold atoms as the exciting UV radiation frequency passes through the Rydberg transition frequency. The energies of various nS configurations are obtained in a broad range of the principal quantum number n from 38 to 165. The values of the quantum defect and ionization energy obtained in experiments and predicted theoretically are discussed.

  20. HESS J1427-608: An Unusual Hard, Unbroken Gamma-Ray Spectrum in a Very Wide Energy Range

    NASA Astrophysics Data System (ADS)

    Guo, Xiao-Lei; Xin, Yu-Liang; Liao, Neng-Hui; Yuan, Qiang; Gao, Wei-Hong; He, Hao-Ning; Fan, Yi-Zhong; Liu, Si-Ming

    2017-01-01

    We report the detection of a GeV γ-ray source that spatially overlaps and is thus very likely associated with the unidentified very high energy (VHE) γ-ray source HESS J1427‑608 with the Pass 8 data recorded by the Fermi Large Area Telescope. The photon spectrum of this source is best described by a power law with an index of 1.85 ± 0.17 in the energy range of 3–500 GeV, and the measured flux connects smoothly with that of HESS J1427‑608 at a few hundred gigaelectronvolts. This source shows no significant extension and time variation. The broadband GeV to TeV emission over four decades of energies can be well fitted by a single power-law function with an index of 2.0, without obvious indication of spectral cutoff toward high energies. Such a result implies that HESS J1427‑608 may be a PeV particle accelerator. We discuss the possible nature of HESS J1427‑608 according to the multiwavelength spectral fittings. Given the relatively large errors, either a leptonic or a hadronic model can explain the multiwavelength data from radio to VHE γ-rays. The inferred magnetic field strength is a few micro-Gauss, which is smaller than the typical values of supernova remnants (SNRs) and is consistent with some pulsar wind nebulae (PWNe). On the other hand, the flat γ-ray spectrum is slightly different from typical PWNe but is similar to that of some known SNRs.

  1. Electrons in a relativistic-intensity laser field: generation of zeptosecond electromagnetic pulses and energy spectrum of the accelerated electrons

    SciTech Connect

    Andreev, A A; Galkin, A L; Kalashnikov, M P; Korobkin, V V; Romanovsky, Mikhail Yu; Shiryaev, O B

    2011-08-31

    We study the motion of an electron and emission of electromagnetic waves by an electron in the field of a relativistically intense laser pulse. The dynamics of the electron is described by the Newton equation with the Lorentz force in the right-hand side. It is shown that the electrons may be ejected from the interaction region with high energy. The energy spectrum of these electrons and the technique of using the spectrum to assess the maximal intensity in the focus are analysed. It is found that electromagnetic radiation of an electron moving in an intense laser field occurs within a small angle around the direction of the electron trajectory tangent. The tangent quickly changes its direction in space; therefore, electromagnetic radiation of the electron in the far-field zone in a certain direction in the vicinity of the tangent is a short pulse with a duration as short as zeptoseconds. The calculation of the temporary and spectral distribution of the radiation field is carried out. (superintense laser fields)

  2. Quasi-energy spectrum and dynamical localizations of two charged particles in a one-dimensional lattice system

    NASA Astrophysics Data System (ADS)

    Wang, Zhi-Gang; Suqing, Duan; Zhao, Xian-Geng

    2006-04-01

    The quasi-energy spectrum of two charged particles in a one-dimensional lattice system driven by an external field are theoretically studied with the help of numerical calculations. It is found that the quasi-energy spectrum splits into two regions. In the gourd-shaped region the Floquet states mainly contain the Wannier states |l,m> (l≠m), which describe the two particles occupy the different sites. The (avoid) crossing points in this region are corresponding to the dynamical localizations of the two particles which initially occupy on different sites when the distance between the initial sites is large. These conditions of dynamical localization are the same as that in single particle system. In the other region (electron electron or electron hole pair region), the Floquet states mainly contain the Wannier states |l,l>, which describe the two particles simultaneously occupy the lth site. The (avoid) crossing points in this region are corresponding to the dynamical localizations of the two particles happening which initially occupy on same site.

  3. Fault feature extraction of planet gear in wind turbine gearbox based on spectral kurtosis and time wavelet energy spectrum

    NASA Astrophysics Data System (ADS)

    Kong, Yun; Wang, Tianyang; Li, Zheng; Chu, Fulei

    2017-09-01

    Planetary transmission plays a vital role in wind turbine drivetrains, and its fault diagnosis has been an important and challenging issue. Owing to the complicated and coupled vibration source, time-variant vibration transfer path, and heavy background noise masking effect, the vibration signal of planet gear in wind turbine gearboxes exhibits several unique characteristics: Complex frequency components, low signal-to-noise ratio, and weak fault feature. In this sense, the periodic impulsive components induced by a localized defect are hard to extract, and the fault detection of planet gear in wind turbines remains to be a challenging research work. Aiming to extract the fault feature of planet gear effectively, we propose a novel feature extraction method based on spectral kurtosis and time wavelet energy spectrum (SK-TWES) in the paper. Firstly, the spectral kurtosis (SK) and kurtogram of raw vibration signals are computed and exploited to select the optimal filtering parameter for the subsequent band-pass filtering. Then, the band-pass filtering is applied to extrude periodic transient impulses using the optimal frequency band in which the corresponding SK value is maximal. Finally, the time wavelet energy spectrum analysis is performed on the filtered signal, selecting Morlet wavelet as the mother wavelet which possesses a high similarity to the impulsive components. The experimental signals collected from the wind turbine gearbox test rig demonstrate that the proposed method is effective at the feature extraction and fault diagnosis for the planet gear with a localized defect.

  4. Fault feature extraction of planet gear in wind turbine gearbox based on spectral kurtosis and time wavelet energy spectrum

    NASA Astrophysics Data System (ADS)

    Kong, Yun; Wang, Tianyang; Li, Zheng; Chu, Fulei

    2017-01-01

    Planetary transmission plays a vital role in wind turbine drivetrains, and its fault diagnosis has been an important and challenging issue. Owing to the complicated and coupled vibration source, time-variant vibration transfer path, and heavy background noise masking effect, the vibration signal of planet gear in wind turbine gearboxes exhibits several unique characteristics: Complex frequency components, low signal-to-noise ratio, and weak fault feature. In this sense, the periodic impulsive components induced by a localized defect are hard to extract, and the fault detection of planet gear in wind turbines remains to be a challenging research work. Aiming to extract the fault feature of planet gear effectively, we propose a novel feature extraction method based on spectral kurtosis and time wavelet energy spectrum (SK-TWES) in the paper. Firstly, the spectral kurtosis (SK) and kurtogram of raw vibration signals are computed and exploited to select the optimal filtering parameter for the subsequent band-pass filtering. Then, the band-pass filtering is applied to extrude periodic transient impulses using the optimal frequency band in which the corresponding SK value is maximal. Finally, the time wavelet energy spectrum analysis is performed on the filtered signal, selecting Morlet wavelet as the mother wavelet which possesses a high similarity to the impulsive components. The experimental signals collected from the wind turbine gearbox test rig demonstrate that the proposed method is effective at the feature extraction and fault diagnosis for the planet gear with a localized defect.

  5. Off-axis holographic lens spectrum-splitting photovoltaic system for direct and diffuse solar energy conversion.

    PubMed

    Vorndran, Shelby D; Chrysler, Benjamin; Wheelwright, Brian; Angel, Roger; Holman, Zachary; Kostuk, Raymond

    2016-09-20

    This paper describes a high-efficiency, spectrum-splitting photovoltaic module that uses an off-axis volume holographic lens to focus and disperse incident solar illumination to a rectangular shaped high-bandgap indium gallium phosphide cell surrounded by strips of silicon cells. The holographic lens design allows efficient collection of both direct and diffuse illumination to maximize energy yield. We modeled the volume diffraction characteristics using rigorous coupled-wave analysis, and simulated system performance using nonsequential ray tracing and PV cell data from the literature. Under AM 1.5 illumination conditions the simulated module obtained a 30.6% conversion efficiency. This efficiency is a 19.7% relative improvement compared to the more efficient cell in the system (silicon). The module was also simulated under a typical meteorological year of direct and diffuse irradiance in Tucson, Arizona, and Seattle, Washington. Compared to a flat panel silicon module, the holographic spectrum splitting module obtained a relative improvement in energy yield of 17.1% in Tucson and 14.0% in Seattle. An experimental proof-of-concept volume holographic lens was also fabricated in dichromated gelatin to verify the main characteristics of the system. The lens obtained an average first-order diffraction efficiency of 85.4% across the aperture at 532 nm.

  6. First Results on the High Energy Cosmic Ray Electron Spectrum from Fermi Lat

    NASA Technical Reports Server (NTRS)

    Moiseev, Alexander

    2009-01-01

    This viewgraph presentation addresses energy reconstruction, electron-hadron separation, validation of Monte Carlo with flight data and an assessment of systematic errors from the Fermi Large Area Telescope.

  7. Energy spectrum of corona impulses generated from insulated wires under high a.c. voltages

    NASA Technical Reports Server (NTRS)

    Doreswamy, C. V.; Padiyar, K. R.; Crowell, C. S.

    1978-01-01

    This paper suggests methods for calculating spectral energy densities of corona impulses generated from insulated conductors. The calculation is based on the data obtained from the measurement of corona pulse waveforms, repetition rates and relevant statistical properties of corona impulses.

  8. Reflection electron energy loss spectrum of single layer graphene measured on a graphite substrate

    NASA Astrophysics Data System (ADS)

    Werner, Wolfgang S. M.; Bellissimo, Alessandra; Leber, Roland; Ashraf, Afshan; Segui, Silvina

    2015-05-01

    Reflection electron energy loss spectra (REELS) have been measured on a highly oriented pyrolytic graphite (HOPG) sample. Two spectra were measured for different energies, 1600 eV, being more sensitive to the bulk and 500 eV being more sensitive to the surface. The energy loss distributions for a single surface and bulk excitation were extracted from the two spectra using a simple decomposition procedure. These single scattering loss distributions correspond to electron trajectories with significantly different penetration depths and agree with energy loss spectra measured on free standing single layer graphene and multilayer graphene (i.e. graphite). This result implies that for a layered electron gas (LEG) material, the number of layers which responds in a correlated fashion to an external perturbation is determined by the depth range penetrated by the external perturbation, and not by the number of layers actually present in the specimen.

  9. The Number of High-Energy Bands in the Photoelectron Spectrum of Alkanes

    NASA Astrophysics Data System (ADS)

    Merris, Russell; Gutman, Ivan

    2000-12-01

    It was observed that within the Bieri-Dill-Heilbronner-Schmelzer model for the calculation of the ion-ization energies of alkanes CnH2n+2, there are exactly n C2s -electron energy levels lying below the degenerate α-ß manifold. We now show that, indeed, this regularity is obeyed by practically all alkane species. Exceptions do exist, but they must possess a (chemically infeasible) group of more than six mutually connected quaternary carbon atoms.

  10. Strain-engineered artificial atom as a broad-spectrum solar energy funnel

    NASA Astrophysics Data System (ADS)

    Feng, Ji; Qian, Xiaofeng; Huang, Cheng-Wei; Li, Ju

    2012-12-01

    An optoelectronic material with a spatially varying bandgap that is tunable is highly desirable for use in photovoltaics, photocatalysis and photodetection. Elastic strain has the potential to be used to achieve rapid and reversible tuning of the bandgap. However, as a result of plasticity or fracture, conventional materials cannot sustain a high enough elastic strain to create sufficient changes in their physical properties. Recently, an emergent class of materials--named `ultrastrength materials'--have been shown to avoid inelastic relaxation up to a significant fraction of their ideal strength. Here, we illustrate theoretically and computationally that elastic strain is a viable agent for creating a continuously varying bandgap profile in an initially homogeneous, atomically thin membrane. We propose that a photovoltaic device made from a strain-engineered MoS2 monolayer will capture a broad range of the solar spectrum and concentrate excitons or charge carriers.

  11. Sensitivity of YAC to measure the light-component spectrum of primary cosmic rays at the ‘knee’ energies

    NASA Astrophysics Data System (ADS)

    Zhai, L. M.; Huang, J.; Chen, D.; Shibata, M.; Katayose, Y.; Zhang, Ying; Liu, J. S.; Chen, Xu; Hu, X. B.; Lin, Y. H.

    2015-04-01

    A new air-shower core-detector array (YAC: Yangbajing air-shower Core-detector array) has been developed to measure the primary cosmic-ray composition at the ‘knee’ energies in Tibet, China, focusing mainly on the light components. The prototype experiment (YAC-I) consisting of 16 detectors has been constructed and operated at Yangbajing (4300 m a.s.l.) in Tibet since May 2009. YAC-I is installed in the Tibet-III AS array and operates together. In this paper, we performed a Monte Carlo simulation to check the sensitivity of the YAC-I+Tibet-III array to the cosmic-ray light component of cosmic rays around the knee energies, taking account of the observation conditions of the actual YAC-I+Tibet-III array. The selection of light component from others was made by use of an artificial neural network. The simulation shows that the light-component spectrum estimated by our methods can well reproduce the input ones within 10% error, and there will be about 30% systematic errors mostly induced by the primary and interaction models used. It is found that the full-scale YAC and the Tibet-III array is powerful to study the cosmic-ray composition, in particular, to obtain the energy spectra of protons and helium nuclei around the knee energies.

  12. The threshold photoelectron spectrum of cyanovinylacetylene leads to an upward revision of the ionization energy

    NASA Astrophysics Data System (ADS)

    Holzmeier, Fabian; Lang, Melanie; Fischer, Ingo; Hemberger, Patrick

    2015-10-01

    Cyanovinylacetylene C5H3N was investigated by threshold photoelectron spectroscopy. The ionization energy (IE) was determined to be 10.04 eV. This value constitutes an upward revision of the earlier value of 9.33 eV. For both stereoisomers (trans and cis) computations predict very similar IEs and spectra. At 11.08 eV and 11.17 eV excited cationic states are observed. For the precursor 3-bromopyridine an IE of 9.34 eV was obtained. The appearance energy AE0K (3-bromopyridine, 3-pyridyl+) was determined to be 11.71 eV and a bond dissociation energy of the Csbnd Br bond in the 3-bromopyridine cation of 229 kJ mol-1 was derived.

  13. Energy spectrum inverse problem of q-deformed harmonic oscillator and entanglement of composite bosons

    NASA Astrophysics Data System (ADS)

    Sang, Nguyen Anh; Thu Thuy, Do Thi; Loan, Nguyen Thi Ha; Lan, Nguyen Tri; Viet, Nguyen Ai

    2017-06-01

    Using the simple deformed three-level model (D3L model) proposed in our early work, we study the entanglement problem of composite bosons. Consider three first energy levels are known, we can get two energy separations, and can define the level deformation parameter δ. Using connection between q-deformed harmonic oscillator and Morse-like anharmonic potential, the deform parameter q also can be derived explicitly. Like the Einstein’s theory of special relativity, we introduce the observer e˙ects: out side observer (looking from outside the studying system) and inside observer (looking inside the studying system). Corresponding to those observers, the outside entanglement entropy and inside entanglement entropy will be defined.. Like the case of Foucault pendulum in the problem of Earth rotation, our deformation energy level investigation might be useful in prediction the environment e˙ect outside a confined box.

  14. Evidence for mirror dark matter from the CDMS low energy electron recoil spectrum

    SciTech Connect

    Foot, R.

    2009-11-01

    We point out that mirror dark matter predicts low-energy (E{sub R} < or approx. 2 keV) electron recoils from mirror electron scattering as well as nuclear recoils from mirror ion scattering. The former effect is examined and applied to the recently released low-energy electron recoil data from the CDMS Collaboration. We speculate that the sharp rise in electron recoils seen in CDMS below 2 keV might be due to mirror electron scattering and show that the parameters suggested by the data are roughly consistent with the mirror dark matter explanation of the annual modulation signal observed in the DAMA/Libra and DAMA/NaI experiments. Thus, the CDMS data offer tentative evidence supporting the mirror dark matter explanation of the DAMA experiments, which can be more rigorously checked by future low-energy electron recoil measurements.

  15. High-energy gamma-ray emission from solar flares: Constraining the accelerated proton spectrum

    NASA Technical Reports Server (NTRS)

    Alexander, David; Dunphy, Philip P.; Mackinnon, Alexander L.

    1994-01-01

    Using a multi-component model to describe the gamma-ray emission, we investigate the flares of December 16, 1988 and March 6, 1989 which exhibited unambiguous evidence of neutral pion decay. The observations are then combined with theoretical calculations of pion production to constrain the accelerated proton spectra. The detection of pi(sup 0) emission alone can indicate much about the energy distribution and spectral variation of the protons accelerated to pion producing energies. Here both the intensity and detailed spectral shape of the Doppler-broadened pi(sup 0) decay feature are used to determine the spectral form of the accelerated proton energy distribution. The Doppler width of this gamma-ray emission provides a unique diagnostic of the spectral shape at high energies, independent of any normalisation. To our knowledge, this is the first time that this diagnostic has been used to constrain the proton spectra. The form of the energetic proton distribution is found to be severely limited by the observed intensity and Doppler width of the pi(sup 0) decay emission, demonstrating effectively the diagnostic capabilities of the pi(sup 0) decay gamma-rays. The spectral index derived from the gamma-ray intensity is found to be much harder than that derived from the Doppler width. To reconcile this apparent discrepancy we investigate the effects of introducing a high-energy cut-off in the accelerated proton distribution. With cut-off energies of around 0.5-0.8 GeV and relatively hard spectra, the observed intensities and broadening can be reproduced with a single energetic proton distribution above the pion production threshold.

  16. Initial concept for forecasting the flux and energy spectrum of energetic particles using ground-level cosmic ray observations

    NASA Astrophysics Data System (ADS)

    Dorman, Lev; Zukerman, Igor

    We describe the principles and operation of automated programs ``FEP-Research-1st Alert'', ``FEP-Research-2nd Alert'', and ``FEP-Research-3rd Alert''. The program ``FEP-Research-lst Alert'' gives preliminary determinations of the energy spectrum and flux at the beginning of an event on the basis of 1-minute data of total neutron intensity and intensities of different multiplicities in the neutron monitor (NM) at the Emilio Segre' Observatory (2025m above sea level, Rc = 10.8 GV) as well as available 1-minute on-line data in the near future of Cosmic Ray Observatories which collaborate with the Israel Cosmic Ray Center (Rome, Haleakala, Climax, Oulu, Moscow, Apatity, Mexico, Aragaz and others). Using well-known coupling functions for neutron monitors we have derived functions that relate the spectral index of flare energetic particles (FEP) to observations of multiplicities. We also derived important functions using ratios of FEP observations from the different cosmic ray monitors mentioned above. All these functions are approximated analytically with good accuracy and can be used for automatic realtime determination of the energy spectrum and fluxes of FEP. Using approximate values of the diffusion coefficient for the current level of solar activity as a function of particle energy, the program ``FEP-Research-1st Alert'' determines very roughly the expected level of radiation in space after (1)/(2), 1, (3)/(2) and 2 hours. If this level is expected to be dangerous for satellites and spacecrafts, the program ``FEP- Research-1st Alert'' sends preliminary 1st Alert. More accurate forecasts are given after 5-10 minutes by the program ``FEP-Research-2nd Alert'', and after 10-20 minutes program by the ``FEP-Research-3rd Alert'' using information on the diffusion coefficient obtained from on-line FEP ground data.

  17. Wavelengths, Transition Probabilities, and Energy Levels for the Spectrum of Neutral Strontium (Sr I)

    NASA Astrophysics Data System (ADS)

    Sansonetti, J. E.; Nave, G.

    2010-09-01

    Following a critical review of spectroscopic data for neutral strontium (Z=38), the energy levels, with designations and uncertainties, have been tabulated. Wavelengths with classifications, intensities, and transition probabilities have also been reviewed. In addition, the 5s S1/22, 4d D3/22, and 4d D5/22 ionization energies have been listed. A summary of the current state of measurements of the SrI 5s2 S01-5s5p P0∘3, F =9/2 atomic clock transition, and other isotopic observations has also been included.

  18. CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES: Theoretical Calculation of Energy Spectrum of YGG:Cr3+ and Thermal Shifts of Its R-Lines

    NASA Astrophysics Data System (ADS)

    Yang, Kuo; Zhang, Ji-Ping

    2009-05-01

    With the strong-field scheme and trigonal bases, the complete d3 energy matrix in a trigonally distorted cubic-field has been constructed. By diagonalizing this matrix, the energy spectrum of YGG:Cr3+ at normal pressure and low temperature has been calculated. The g factor of the ground-state has been evaluated in terms of the energy spectrum. At the same time, by using the wavefunctions obtained from diagonalizing the complete d3 energy matrix and Thermal Shifts theory, we calculate the thermal shifts of the sharp lines of YGG:Cr3+ and determine the relevant parameters. The calculated results are all in good agreement with the optical-spectrum and EPR experimental data. It is demonstrated that the obtained wavefunctions and the values of parameters are reasonable.

  19. Morphology effects of self-assembled quantum dots on the energy spectrum of magneto-excitons

    NASA Astrophysics Data System (ADS)

    Villamil, Pablo; Sierra Ortega, José

    2014-02-01

    In this paper we analyze the changes experienced by the energy spectra of a confined exciton in type II semiconductor quantum dots, considering the quantum dot as a possible functional part that, in the future devices, can be applied in spintronics, optoelectronics, and quantum information technologies. We studied the lowest energy states of an exciton (X) confined in type II InP/GaInP self-assembled quantum dot (SAQDs), with axial symmetry in the presence of a uniformly applied magnetic field in the growth direction. In our model, it is considered that the electron is located within the point of InP and the hole is in the GaInP barrier. The solution of the Schrödinger equation for this system is obtained by a variational separation process of variables in the adiabatic approximation limit and within the effective mass approximation. We study the energy levels associated with the electron and the hole, and the energy of the exciton. Due to the axial symmetry of the problem the z component of the total orbital angular momentum, Lz=le+lh, is preserved and the exciton states are classified according to the values of this component. Quantum dots have a finite and variable thickness, with the purpose of analyzing the effects related to the variation of the morphology and the presence of a wet layer.

  20. Solar Atmospheric Magnetic Energy Coupling: Broad Plasma Conditions and Spectrum Regimes

    NASA Astrophysics Data System (ADS)

    Orange, N. Brice; Chesny, David L.; Gendre, Bruce; Morris, David C.; Oluseyi, Hakeem M.

    2016-12-01

    Solar variability investigations that include magnetic energy coupling are paramount to solving many key solar/stellar physics problems, particularly for understanding the temporal variability of magnetic energy redistribution and heating processes. Using three years of observations from the Solar Dynamics Observatory’s Atmospheric Imaging Assembly and Heliosemic Magnetic Imager, we measured radiative and magnetic fluxes from gross features and at full-disk scales, respectively. Magnetic energy coupling analyses support radiative flux descriptions via the plasma heating connectivity of dominant (magnetic) and diffuse components, specifically of the predominantly closed-field corona. Our work shows that this relationship favors an energetic redistribution efficiency across large temperature gradients, and potentially sheds light on the long-standing issue of diffuse unresolved low corona emission. The close connection between magnetic energy redistribution and plasma conditions revealed by this work lends significant insight into the field of stellar physics, as we have provided possible means for probing distant sources in currently limited and/or undetectable radiation distributions.

  1. The ultraviolet spectrum and continuum energy distribution of the bright quasar H1821 + 643

    NASA Technical Reports Server (NTRS)

    Kolman, Michiel; Halpern, Jules P.; Shrader, Chris R.; Filippenko, Alexei V.

    1991-01-01

    The first UV observations of the bright QSO H1821 + 643 are reported. With V = 14.2 mag and z = 0.297, H1821 + 643 is the second brightest object in the sky at z above 0.1. The IUE data are combined with new optical spectroscopy, and existing IR and X-ray data, to reveal a strong optical/UV 'big bump', which continues past the Lyman limit in the rest frame of the QSO. A possible turnover at the high-frequency side of the UV continuum constrains fits of a thin accretion disk model to a large black hole mass and high accretion rate, but a small disk size. The shape of the UV continuum was found to be variable, with a hardening of the spectrum when the source was brighter. Because of its location, only 3 deg from the ecliptic pole, H1821 + 643 will be an important object for simultaneous UV and soft X-ray monitoring to test for a common origin of the UV bump and soft X-ray excess.

  2. The expected high-energy to ultra-high-energy gamma-ray spectrum of the Crab Nebula

    NASA Technical Reports Server (NTRS)

    De Jager, O. C.; Harding, A. K.

    1992-01-01

    The inverse Compton scattering model for the unpulsed TeV emission from the Crab Nebula is reexamined using the magnetic field distribution derived from MHD flow models of the nebula. It is shown that the observed flux can be explained if the average nebular field is indeed about 0.0003, as is predicted by the spectral break between radio and optical. The brightness distribution of the TeV gamma-ray signal is expected to extend out to about 1.5 arcmin from the pulsar. The present estimates predict a steady flux of unpulsed ultrahigh-energy gamma-rays due to the inverse Compton scattering of soft photons by shock-accelerated electrons and/or positrons in the vicinity of the shock.

  3. The expected high-energy to ultra-high-energy gamma-ray spectrum of the Crab Nebula

    NASA Technical Reports Server (NTRS)

    De Jager, O. C.; Harding, A. K.

    1992-01-01

    The inverse Compton scattering model for the unpulsed TeV emission from the Crab Nebula is reexamined using the magnetic field distribution derived from MHD flow models of the nebula. It is shown that the observed flux can be explained if the average nebular field is indeed about 0.0003, as is predicted by the spectral break between radio and optical. The brightness distribution of the TeV gamma-ray signal is expected to extend out to about 1.5 arcmin from the pulsar. The present estimates predict a steady flux of unpulsed ultrahigh-energy gamma-rays due to the inverse Compton scattering of soft photons by shock-accelerated electrons and/or positrons in the vicinity of the shock.

  4. High energy pulses generation with giant spectrum bandwidth and submegahertz repetition rate from a passively mode-locked Yb-doped fiber laser in all normal dispersion cavity

    NASA Astrophysics Data System (ADS)

    Lin, J.-H.; Wang, D.; Lin, K.-H.

    2011-01-01

    Robust passively mode-locked pulse generation with low pulse repetition rate and giant spectrum bandwidth in an all-fiber, all-normal-dispersion ytterbium-doped fiber laser has been experimentally demonstrated using nonlinear polarization evolution technique. The highest pulse energy over 20 nJ with spectrum bandwidth over 50 nm can be experimentally obtained at 175 mW pump power. The mode-locked pulses reveal broadened 3-dB pulsewidth about several nanosecond and widened pedestal in time trace that is resulted from enormous dispersion in laser cavity and gain dynamics. At certain mode-locking state, a spectrum gap around 1056 nm are observed between the three and four energy levels of Yb-doped fiber laser. By properly rotating the polarization controller, the gap can be eliminated due to four-wave mixing to produce more flattened spectrum output.

  5. Evaluation using m.c.n.p. code of the bremsstrahlung energy spectrum produced by interactions between structural materials and accelerated electrons

    NASA Astrophysics Data System (ADS)

    Calderaro, Elio

    2004-09-01

    In order to design the biological shield of industrial accelerator plants, it is needed to have a good knowledge of the bremsstrahlung energy spectrum and the intensity of the bremsstrahlung produced by electron interactions with both products (usually water equivalent) and structural materials such as concrete, iron, aluminium. Using the MCNP code, a normalized bremsstrahlung energy spectrum was obtained for materials with average atomic number lower than or equal to 13 and irradiated with 5 and 10 Mev electrons, respectively; multiplying the spectrum by suitable coefficients, it was possible to obtain the real spectrum for materials such as water, concrete, aluminium and iron. The MCNP results have been obtained with relative error less than 2%.

  6. Development of a Low Energy Particle Electron Spectrum Analyzer (LEP-ESA) onboard the ICI-2 sounding rocket

    NASA Astrophysics Data System (ADS)

    Harada, M.; Saito, Y.; Yokota, S.; Saito, M.; Asamura, K.; Kasahara, S.

    2008-12-01

    Strong HF radar backscatter echoes are well-known characteristics of the polar cusp region by the ground- based observation of HF radar in the polar ionosphere. The gradient drift instability is regarded as a dominant mode for producing backscatter targets. According to Moen et al. [2002], decameter scale measurement that cannot be achieved by ground-based and satellite observations is required to understand the generation mechanism. Norwegian sounding rocket experiment ICI-2(Investigation of Cusp Irregularities) is proposed in order to single out the mechanism(s) running cusp ionospheric plasma unstable and facilitate backscatter targets for HF radars. The ICI-2 rocket will be launched into cusp ionosphere from Svalbard, Norway in Nov/Dec 2008. We are responsible for developing a low energy particle electron spectrum analyzer (LEP-ESA) that is one of the science payloads onboard the ICI-2 sounding rocket. LEP-ESA covers the energy range between 10eV and 10keV. We designed LEP-ESA to achieve high spatial resolution of ~10m/energy spectrum (16 energy steps). We have confirmed the performance of LEP-ESA by experiments as well as numerical simulations. In order to realize the high spatial resolution, high time resolution is required. For the purpose of high time resolution measurement of low energy electrons we have newly developed an electron detector that consists of Z-stack MCPs (Micro Channel Pates) and 64-channel multi-anode. An ASIC (Application Specific Integrated Circuit) with 64-channel fast preamplifiers and counters are installed on the backside of the anode. Since the detected electrons are independently counted by 64 separated anodes, multi-anode can achieve the higher time resolution than any other position sensitive anodes. One of the most severe problems in using a multi- anode is the size of the required electronics that becomes unacceptably large for the sounding rocket / satellite instrument when the number of the channels is large. By using the

  7. Energy spectrum of D{sup 0} centre in a spherical Gaussian quantum dot

    SciTech Connect

    Boda, Aalu Chatterjee, Ashok

    2015-05-15

    The properties of a neutral hydrogenic donor (D{sup 0}) centres have been studied for a GaAs semiconductor quantum dot with the Gaussian confinement potential. The energy levels of the ground state (n = 1) and the excited states of both the first excited (n = 2) and second excited (n = 3) configurations have been calculated by variational method. It has been shown that the excited states of the (D{sup 0}) centre in quantum dot are bound for sufficiently strong confinement potential. The conditions of binding for the ground state as well as excited states have been determined as functions of the potential strength and quantum dot radius. The ground state electron energy is compared with those available in the literature.

  8. [Vascular architectonics of eye and orbital space in color reflection of doppler spectrum energy].

    PubMed

    Kharlap, S I

    1999-01-01

    Super-sharp gray scale image and highly sensitive digital wide-band Doppler, three-dimensional visualization of vessels in the pulsed energy Doppler mode were used in examination of the posterior segment of the eye, optic nerve, and orbital space. Twelve healthy volunteers (24 eyes) aged 25-45 years were examined. The architectonics of the optic disk and the blood filling of the arterial Zinn-Haller circle, reticular platelet, choroid, posterior long and posterior short ciliary arteries were studied. Vascular architectonics of the retrobulbar space was studied by the three-dimensional reconstruction in the energy Doppler mode and the borders of the vascular plexus round the optic nerve were defined.

  9. The High Energy X-ray Spectrum of 4U1700-37 Observed from OSO-8

    NASA Technical Reports Server (NTRS)

    Dolan, J. F.; Coe, M. J.; Crannell, C. J.; Dennis, B. R.; Frost, K. J.; Maurer, G. S.; Orwig, L. E.

    1979-01-01

    The most intense hard X-ray source in the confused region in Scorpius is identified as 4U1700-37. The 3.4-day modulation is seen above 20 keV with the intensity during eclipse being consistent with zero flux. The photon-number spectrum from 20 to 150 keV is well represented by a single power law with a photo-number spectral index of -2.77 + or - 0.35 or by a thermal bremsstrahlung spectrum with kT = 27 96.8-min X-ray modulation previously reported at lower energies. Despite the difficulties in reconciling both the lack of periodic modulation in the emitted X-radiation and the orbital dynamics of the system with theories of the evolution and physical properties of neutron stars, the observed properties of 4U1700-37 are all consistent with the source being a spherically accreting neutron star rather than a black hole.

  10. Detecting single atoms of calcium and iron in biological structures by electron energy-loss spectrum-imaging.

    PubMed

    Leapman, R D

    2003-04-01

    As techniques for electron energy-loss spectroscopy (EELS) reach a higher degree of optimization, experimental detection limits for analysing biological structures are approaching values predicted by the physics of the electron scattering. Theory indicates that it should be possible to detect a single atom of certain elements like calcium and iron contained in a macromolecular assembly using a finely focused probe in the scanning transmission electron microscope (STEM). To test this prediction, EELS elemental maps have been recorded with the spectrum-imaging technique in a VG Microscopes HB501 STEM coupled to a Gatan Enfina spectrometer, which is equipped with an efficient charge-coupled device (CCD) array detector. By recording spectrum-images of haemoglobin adsorbed onto a thin carbon film, it is shown that the four heme groups in a single molecule can be detected with a signal-to-noise ratio of approximately 10 : 1. Other measurements demonstrate that calcium adsorbed onto a thin carbon film can be imaged at single atom sensitivity with a signal-to-noise ratio of approximately 5 : 1. Despite radiation damage due to the necessarily high electron dose, it is anticipated that mapping single atoms of metals and other bound elements will find useful applications in characterizing large protein assemblies.

  11. [Energy dispersive spectrum analysis of surface compositions of selective laser melting cobalt-chromium alloy fabricated by different processing parameters].

    PubMed

    Qian, Liang; Zeng, Li; Wei, Bin; Gong, Yao

    2015-06-01

    To fabricate selective laser melting cobalt-chromium alloy samples by different processing parameters, and to analyze the changes of energy dispersive spectrum(EDS) on their surface. Nine groups were set up by orthogonal experimental design according to different laser powers,scanning speeds and powder feeding rates(laser power:2500-3000 W, scanning speed: 5-15 mm/s, powder feeding rate: 3-6 r/min). Three cylinder specimens(10 mm in diameter and 3 mm in thickness) were fabricated in each group through Rofin DL 035Q laser cladding system using cobalt-chromium alloy powders which were developed independently by our group.Their surface compositions were then measured by EDS analysis. Results of EDS analysis of the 9 groups fabricated by different processing parameters(Co:62.98%-67.13%,Cr:25.56%-28.50%,Si:0.49%-1.23%) were obtained. They were similar to the compositions of cobalt-chromium alloy used in dental practice. According to EDS results, the surface compositions of the selective laser melting cobalt-chromium alloy samples are stable and controllable, which help us gain a preliminary sight into the range of SLM processing parameters. Supported by "973" Program (2012CB910401) and Research Fund of Science and Technology Committee of Shanghai Municipality (12441903001 and 13140902701).

  12. Components Makeover Gives Concentrating Solar Power a Boost (Fact Sheet), The Spectrum of Clean Energy Innovation

    SciTech Connect

    Not Available

    2010-12-01

    Parabolic trough technology is the most mature of the various concentrating solar power (CSP) options. But scientists at the National Renewable Energy Laboratory (NREL) continue to make advances on trough systems through innovative research on various components in industrial partnerships with Acciona Solar Power, SkyFuel, Schott Solar, and others. The results are leading to improved system efficiencies and lower costs for CSP plants.

  13. Advanced Condenser Boosts Geothermal Power Plant Output (Fact Sheet), The Spectrum of Clean Energy Innovation

    SciTech Connect

    Not Available

    2010-12-01

    When power production at The Geysers geothermal power complex began to falter, the National Renewable Energy Laboratory (NREL) stepped in, developing advanced condensing technology that dramatically boosted production efficiency - and making a major contribution to the effective use of geothermal power. NREL developed advanced direct-contact condenser (ADCC) technology to condense spent steam more effectively, improving power production efficiency in Unit 11 by 5%.

  14. Weighing the evidence: energy determinations across the spectrum of kidney disease.

    PubMed

    Byham-Gray, Laura D

    2006-01-01

    Evidence based guidelines for medical nutrition therapy (MNT) in chronic kidney disease (CKD) recommend a range of caloric levels, dependent on age and level of kidney function. Recent literature has explored whether current research findings still support these earlier conclusions, and if new energy determinations for CKD are warranted. This review will take a brief look at the history of the controversy, examine the research evidence at the time of practice guideline development, investigate emerging research, and discuss implications for additional scientific inquiry.

  15. Eigenvalue spectrum of the independent-fermion kinetic-energy kernel

    SciTech Connect

    Joubert, D.

    1996-09-01

    The constrained minimization independent-fermion kinetic-energy kernel, {delta}{sup 2}{ital T}{sub {ital s}}[{rho}]/{delta}{rho}({bold r}){delta}{rho}({bold r}{sup {prime}}), has a zero mode for all {rho}({bold r}), while it is non-negative for {rho}({bold r}) noninteracting {ital v} representable. {copyright} {ital 1996 The American Physical Society.}

  16. Coarse-scaling adjustment of fine-group neutron spectra for epithermal neutron beams in BNCT using multiple activation detectors

    NASA Astrophysics Data System (ADS)

    Liu, Yuan-Hao; Nievaart, Sander; Tsai, Pi-En; Liu, Hong-Ming; Moss, Ray; Jiang, Shiang-Huei

    2009-01-01

    In order to provide an improved and reliable neutron source description for treatment planning in boron neutron capture therapy (BNCT), a spectrum adjustment procedure named coarse-scaling adjustment has been developed and applied to the neutron spectrum measurements of both the Tsing Hua Open-pool Reactor (THOR) epithermal neutron beam in Taiwan and the High Flux Reactor (HFR) in The Netherlands, using multiple activation detectors. The coarse-scaling adjustment utilizes a similar idea as the well-known two-foil method, which adjusts the thermal and epithermal neutron fluxes according to the Maxwellian distribution for thermal neutrons and 1/ E distribution over the epithermal neutron energy region. The coarse-scaling adjustment can effectively suppress the number of oscillations appearing in the adjusted spectrum and provide better smoothness. This paper also presents a sophisticated 9-step process utilizing twice the coarse-scaling adjustment which can adjust a given coarse-group spectrum into a fine-group structure, i.e. 640 groups, with satisfactory continuity and excellently matched reaction rates between measurements and calculation. The spectrum adjustment algorithm applied in this study is the same as the well-known SAND-II.

  17. Application of K-Space Energy Spectrum Analysis for Inherent and Dynamic B0 Mapping and Deblurring in Spiral Imaging

    PubMed Central

    Truong, Trong-Kha; Chen, Nan-kuei; Song, Allen W.

    2010-01-01

    Spiral imaging is vulnerable to spatial and temporal variations of the static magnetic field (B0) caused by susceptibility effects, eddy currents, chemical shifts, subject motion, physiological noise, and system instabilities, resulting in image blurring. Here, a novel off-resonance correction method is proposed to address these issues. A k-space energy spectrum analysis (KESA) algorithm is first applied to inherently and dynamically generate a B0 map from the k-space data at each time point, without requiring any additional data acquisition, pulse sequence modification, or phase unwrapping. A simulated phase evolution rewinding (SPHERE) algorithm and an automatic residual deblurring algorithm are then used to correct for the blurring caused by both spatial and temporal B0 variations, resulting in a high spatial and temporal fidelity. This method is validated against conventional B0 mapping and deblurring methods and its advantages for dynamic MRI applications are demonstrated in functional MRI studies. PMID:20564589

  18. Energy Spectrum Measurements of Cosmic-Ray Hydrogen and Helium Isotopes with the BESS-Polar II Instrument

    NASA Astrophysics Data System (ADS)

    Picot-Clemente, Nicolas

    2014-03-01

    The Balloon-Borne Experiment with a Superconducting Spectrometer (BESS-Polar II) flew successfully over Antarctica during 24.5 days in December 2007 through January 2008 during a period of minimum solar activity. The long duration of the flight, and the good stability of the detectors, improved by a factor of 5 the number of cosmic-ray events previously recorded with BESS-Polar I, reaching about 4.7 billion collected particles. Energy spectrum of cosmic-ray hydrogen and helium isotopes have been measured with the instrument from 0.2 to about 1.5 GeV/n, with unprecedented accuracy. These new flux and ratio measurements provide important information to better understand the propagation history of cosmic rays in the Galaxy. The results obtained with the BESS-Polar II instrument will be presented and compared with different propagation models.

  19. On the high energy cut-off in the gamma-ray spectrum from Cygnus X-3

    NASA Astrophysics Data System (ADS)

    Stephens, S. A.; Verma, R. P.

    The effect of magnetic pair production on the high energy gamma-rays from Cygnus X-3 is examined, while traversing the field associated with the radio emitting region of this source. It is shown that such a process would result in a sharp steepening of the gamma-ray spectrum beyond about 10 to the 15th eV. Using the observed spectral steepening, a field strength of 0.7 gauss in the region about 10 to the 14th cms is derived, where most of the observed radio emission takes place. The observed light curve shows only one significant peak at a phase of about 0.2 from the X-ray minimum. This could result from the magnetic bending of the charged particles from the pulsar before interacting with the enshrouded matter. It is predicted that the relative contribution of steady flux would increase beyond 10 to the 16th eV.

  20. Precision analysis of electron energy spectrum and angular distribution of neutron β- decay with polarized neutron and electron

    NASA Astrophysics Data System (ADS)

    Ivanov, A. N.; Höllwieser, R.; Troitskaya, N. I.; Wellenzohn, M.; Berdnikov, Ya. A.

    2017-05-01

    We give a precision analysis of the correlation coefficients of the electron energy spectrum and angular distribution of the β- decay and radiative β- decay of the neutron with polarized neutron and electron to order 10-3. The calculation of correlation coefficients is carried out within the standard model, with contributions of order 10-3 caused by the weak magnetism and proton recoil taken to next-to-leading order in the large proton mass expansion, and with radiative corrections of order α /π ˜10-3 calculated to leading order in the large proton mass expansion. The obtained results can be used for the planning of experiments on the search for contributions of order 10-4 of interactions beyond the standard model.

  1. The energy spectrum of cosmic rays above 1017.2 eV measured by the fluorescence detectors of the Telescope Array experiment in seven years

    NASA Astrophysics Data System (ADS)

    Abbasi, R. U.; Abe, M.; Abu-Zayyad, T.; Allen, M.; Azuma, R.; Barcikowski, E.; Belz, J. W.; Bergman, D. R.; Blake, S. A.; Cady, R.; Cheon, B. G.; Chiba, J.; Chikawa, M.; Cho, W. R.; Fujii, T.; Fukushima, M.; Goto, T.; Hanlon, W.; Hayashi, Y.; Hayashida, N.; Hibino, K.; Honda, K.; Ikeda, D.; Inoue, N.; Ishii, T.; Ishimori, R.; Ito, H.; Ivanov, D.; Jui, C. C. H.; Kadota, K.; Kakimoto, F.; Kalashev, O.; Kasahara, K.; Kawai, H.; Kawakami, S.; Kawana, S.; Kawata, K.; Kido, E.; Kim, H. B.; Kim, J. H.; Kim, J. H.; Kitamura, S.; Kitamura, Y.; Kuzmin, V.; Kwon, Y. J.; Lan, J.; Lundquist, J. P.; Machida, K.; Martens, K.; Matsuda, T.; Matsuyama, T.; Matthews, J. N.; Minamino, M.; Mukai, Y.; Myers, I.; Nagasawa, K.; Nagataki, S.; Nakamura, T.; Nonaka, T.; Nozato, A.; Ogio, S.; Ogura, J.; Ohnishi, M.; Ohoka, H.; Oki, K.; Okuda, T.; Ono, M.; Oshima, A.; Ozawa, S.; Park, I. H.; Pshirkov, M. S.; Rodriguez, D. C.; Rubtsov, G.; Ryu, D.; Sagawa, H.; Sakurai, N.; Scott, L. M.; Shah, P. D.; Shibata, F.; Shibata, T.; Shimodaira, H.; Shin, B. K.; Shin, H. S.; Smith, J. D.; Sokolsky, P.; Springer, R. W.; Stokes, B. T.; Stratton, S. R.; Stroman, T. A.; Suzawa, T.; Takamura, M.; Takeda, M.; Takeishi, R.; Taketa, A.; Takita, M.; Tameda, Y.; Tanaka, H.; Tanaka, K.; Tanaka, M.; Thomas, S. B.; Thomson, G. B.; Tinyakov, P.; Tkachev, I.; Tokuno, H.; Tomida, T.; Troitsky, S.; Tsunesada, Y.; Tsutsumi, K.; Uchihori, Y.; Udo, S.; Urban, F.; Vasiloff, G.; Wong, T.; Yamane, R.; Yamaoka, H.; Yamazaki, K.; Yang, J.; Yashiro, K.; Yoneda, Y.; Yoshida, S.; Yoshii, H.; Zollinger, R.; Zundel, Z.

    2016-07-01

    The Telescope Array (TA) experiment is the largest detector to observe ultra-high-energy cosmic rays in the northern hemisphere. The fluorescence detectors at two stations of TA are newly constructed and have now completed seven years of steady operation. One advantage of monocular analysis of the fluorescence detectors is a lower energy threshold for cosmic rays than that of other techniques like stereoscopic observations or coincidences with the surface detector array, allowing the measurement of an energy spectrum covering three orders of magnitude in energy. Analyzing data collected during those seven years, we report the energy spectrum of cosmic rays covering a broad range of energies above 1017.2eV measured by the fluorescence detectors and a comparison with previously published results.

  2. Application of k-space energy spectrum analysis to susceptibility field mapping and distortion correction in gradient-echo EPI.

    PubMed

    Chen, Nan-kuei; Oshio, Koichi; Panych, Lawrence P

    2006-06-01

    Echo-planar imaging (EPI) is widely used in functional MRI studies. It is well known that EPI quality is usually degraded by geometric distortions, when there exist susceptibility field inhomogeneities. EPI distortions may be corrected if the field maps are available. It is possible to estimate the susceptibility field gradients from the phase reconstruction of a single-TE EPI image, after a successful phase-unwrapping procedure. However, in regions affected by pronounced field gradients, the phase-unwrapping of a single-TE image may fail, and therefore the estimated field maps may be incorrect. It has been reported that the field inhomogeneity may be calculated more reliably from T2*-weighted images corresponding to multiple TEs. However, the multi-TE MRI field mapping increases the scan time. Furthermore, the measured field maps may be invalid if the subject's position changes during dynamic scans. To overcome the limitations in conventional field mapping approaches, a novel k-space energy spectrum analysis algorithm is developed, which quantifies the spatially dependent echo-shifting effect and the susceptibility field gradients directly from the k-space data of single-TE gradient-echo EPI. Using the k-space energy spectrum analysis, susceptibility field gradients can be reliably measured without phase-unwrapping, and EPI distortions can be corrected without extra field mapping scans or pulse sequence modification. The reported technique can be used to retrospectively improve the image quality of the previously acquired EPI and functional MRI data, provided that the complex-domain k-space data are still available.

  3. Ensemble fluctuations of the cosmic ray energy spectrum and the intergalactic magnetic field

    NASA Astrophysics Data System (ADS)

    Supanitsky, A. D.; Medina-Tanco, G.

    2015-06-01

    The origin of the most energetic cosmic ray particles is one of the most important open problems in astrophysics. Despite a big experimental effort done in the past years, the sources of these very energetic particles remain unidentified. Therefore, their distribution on the Universe and even their space density are still unknown. It has been shown that different spatial configurations of the sources lead to different energy spectra and composition profiles (in the case of sources injecting heavy nuclei) at Earth. These ensemble fluctuations are more important at the highest energies, because only nearby sources, which are necessarily few, can contribute to the flux observed at Earth. This is due to the interaction of the cosmic rays with the low energy photons of the radiation field, present in the intergalactic medium, during propagation. It is believed that the intergalactic medium is permeated by a turbulent magnetic field. Although at present it is still unknown, there are several constraints for its intensity and coherence length obtained from different observational techniques. Charged cosmic rays are affected by the intergalactic magnetic field because of the bending of their trajectories during propagation through the intergalactic medium. In this work, the influence of the intergalactic magnetic field on the ensemble fluctuations is studied. Sources injecting only protons and only iron nuclei are considered. The ensemble fluctuations are studied for different values of the density of sources compatible with the constraints recently obtained from cosmic ray data. Also, the possible detection of the ensemble fluctuations in the context of the future JEM-EUSO mission is discussed.

  4. ELECTROMAGNETISM, OPTICS, ACOUSTICS, HEAT TRANSFER, CLASSICAL MECHANICS, AND FLUID DYNAMICS: Influence of a Single Frequency Electromagnetic Wave on Energy Spectrum of Nonpolariton System in a Kerr Nonlinear Blackbody

    NASA Astrophysics Data System (ADS)

    Zeng, Qi-Jun; Cheng, Ze

    2010-06-01

    In a Kerr nonlinear blackbody, bare photons with opposite wave vectors and helicities are bound into pairs and unpaired photons are transformed into a different kind of quasiparticle, the nonpolariton. The present paper investigates the influence of a single frequency electromagnetic wave on the energy spectrum of the nonpolariton system. We find that the wave can lead to an energy shift of nonpolaritons. Moreover, we calculate the first-order energy shift on certain conditions.

  5. Calculating the energy spectrum of complex low-dimensional heterostructures in the electric field.

    PubMed

    Khonina, Svetlana N; Volotovsky, Sergey G; Kharitonov, Sergey I; Kazanskiy, Nikolay L

    2013-01-01

    An algorithm for solving the steady-state Schrödinger equation for a complex piecewise-constant potential in the presence of the E-field is developed and implemented. The algorithm is based on the consecutive matching of solutions given by the Airy functions at the band boundaries with the matrix rank increasing by no more than two orders, which enables the characteristic solution to be obtained in the convenient form for search of the roots. The algorithm developed allows valid solutions to be obtained for the electric field magnitudes larger than the ground-state energy level, that is, when the perturbation method is not suitable.

  6. Measuring the energy spectrum of primary cosmic rays with the Yakutsk EAS array

    NASA Technical Reports Server (NTRS)

    Khristiansen, G. B.

    1986-01-01

    The Yakutsk Extensive Air Showers (EAS) array was designed for detecting the showers generated by the 10 to the 47th power to 10 to the 20th power eV primary cosmic rays and consists of numerous electron, muon, and Cerenkov light detectors arranged on a 20 sq km area terrain. The array is featured by the feasibility to detect the EAS-produced Cerenkov light, hence, as will be shown, to find the mean energy of the primary particles generating an ensemble of EAS of given size. Date collected is discussed.

  7. Effects of inverse degree on electronic structure and electron energy-loss spectrum in zinc ferrites

    NASA Astrophysics Data System (ADS)

    Sun, D.; Wang, M. X.; Zhang, Z. H.; Tao, H. L.; He, M.; Song, B.; Li, Q.

    2015-12-01

    First-principles calculations were performed to study the effects of inverse degree in zinc ferrite on electronic structure and properties. The electron energy-loss near-edge fine structure (ELNES) were simulated, and the splitting of peak and intensities of the oxygen K-edges can be used to identify the inversion of zinc ferrite. More Fe3+ transferring from the octahedral sites to the tetrahedral sites lead to the changing of the ligand shells surrounding the absorbing atom, accounting for the observed changing in ELNES. The standard criterion for determining the reversal extent of the cations in zinc ferrite by ELNES was given.

  8. Spectrum sensitivity, energy yield, and revenue prediction of PV and CPV modules

    SciTech Connect

    Kinsey, Geoffrey S.

    2015-09-28

    Impact on module performance of spectral irradiance variation has been determined for III-V multijunctions compared against the four most common flat-plate module types (cadmium telluride, multicrystalline silicon, copper indium gallium selenide, and monocrystalline silicon. Hour-by-hour representative spectra were generated using atmospheric variables for Albuquerque, New Mexico, USA. Convolution with published values for external quantum efficiency gave the predicted current output. When combined with specifications of commercial PV modules, energy yield and revenue were predicted. This approach provides a means for optimizing PV module design based on various site-specific temporal variables.

  9. Transition from geostrophic turbulence to inertia–gravity waves in the atmospheric energy spectrum

    PubMed Central

    Callies, Jörn; Ferrari, Raffaele; Bühler, Oliver

    2014-01-01

    Midlatitude fluctuations of the atmospheric winds on scales of thousands of kilometers, the most energetic of such fluctuations, are strongly constrained by the Earth’s rotation and the atmosphere’s stratification. As a result of these constraints, the flow is quasi-2D and energy is trapped at large scales—nonlinear turbulent interactions transfer energy to larger scales, but not to smaller scales. Aircraft observations of wind and temperature near the tropopause indicate that fluctuations at horizontal scales smaller than about 500 km are more energetic than expected from these quasi-2D dynamics. We present an analysis of the observations that indicates that these smaller-scale motions are due to approximately linear inertia–gravity waves, contrary to recent claims that these scales are strongly turbulent. Specifically, the aircraft velocity and temperature measurements are separated into two components: one due to the quasi-2D dynamics and one due to linear inertia–gravity waves. Quasi-2D dynamics dominate at scales larger than 500 km; inertia–gravity waves dominate at scales smaller than 500 km. PMID:25404349

  10. Transition from geostrophic turbulence to inertia-gravity waves in the atmospheric energy spectrum.

    PubMed

    Callies, Jörn; Ferrari, Raffaele; Bühler, Oliver

    2014-12-02

    Midlatitude fluctuations of the atmospheric winds on scales of thousands of kilometers, the most energetic of such fluctuations, are strongly constrained by the Earth's rotation and the atmosphere's stratification. As a result of these constraints, the flow is quasi-2D and energy is trapped at large scales—nonlinear turbulent interactions transfer energy to larger scales, but not to smaller scales. Aircraft observations of wind and temperature near the tropopause indicate that fluctuations at horizontal scales smaller than about 500 km are more energetic than expected from these quasi-2D dynamics. We present an analysis of the observations that indicates that these smaller-scale motions are due to approximately linear inertia-gravity waves, contrary to recent claims that these scales are strongly turbulent. Specifically, the aircraft velocity and temperature measurements are separated into two components: one due to the quasi-2D dynamics and one due to linear inertia-gravity waves. Quasi-2D dynamics dominate at scales larger than 500 km; inertia-gravity waves dominate at scales smaller than 500 km.

  11. Electron energy loss spectrum of graphane from first-principles calculations.

    PubMed

    Nejati, H; Dadsetani, M

    2014-12-01

    In this study, the energy loss near edge structure (ELNES) of carbon atoms in chair and tricycle conformers of hydrogenated graphene, namely 'graphane', has been calculated in the density functional theory using FP-LAPW method, and then, it has been compared with that of graphite and graphene. Using ELNES from chair conformer, the carbon K-edge was found to have a few main features including electron transition from 1s orbital of carbon atom to π*, σ*, and a hybridization of these two states. The first feature in tricycle conformer, however, has contributions of both π* and σ* states. The comparison of ELNES and the unoccupied density of states in each structure also justifies this. The energy difference between π* and σ* features of graphane conformers was decreased relative to it in graphite and graphene. Since the inclusion of core-holes and super-cells is essential for accurate reproduction of features in graphite and graphene, it may be essential as well for the ELNES spectra of graphane conformers. Copyright © 2014 Elsevier Ltd. All rights reserved.

  12. Supernova-Driven Interstellar Medium Simulations: Turbulent Pressure Distribution and Kinetic Energy Spectrum

    NASA Astrophysics Data System (ADS)

    Joung, M. K. R.; Mac Low, M.-M.

    2005-12-01

    We construct three-dimensional models of stratified interstellar medium stirred by discrete supernova explosions, including vertical gravitational field and parameterized heating and cooling, with sufficient spatial resolution to follow detailed gas dynamics using a grid-based adaptive mesh refinement code, Flash. The models reproduce observed characteristics of the Galaxy such as the galactic fountain and cold dense clouds in the galactic disk. We find: (1) Kinetic energy is distributed over a broad range of lengths, but 90% of the total kinetic energy is contained in wavelengths shortward of 150 pc; (2) Turbulent velocity dispersion is inversely proportional to the square root of the local density, making the turbulent pressure nearly constant; (3) The global gas structure depends sensitively on the assumed background diffuse heating rate. We discuss how these high-resolution models can be used as a subgrid model for supernova feedback in global simulations of galaxies. MKRJ was supported by an AMNH Graduate Student Fellowship. M-MML acknowledges support by NSF Career grant AST99-85392, and NSF grants AST03-07793, AST03-07854. The software used in this work was in part developed by the DOE-supported ASCI/Alliance Center for Astrophysical Thermonuclear Flashes at the University of Chicago. Computations were performed at the Pittsburgh Supercomputing Center supported by the NSF.

  13. Optimal quasifree approximation: Reconstructing the spectrum from ground-state energies

    NASA Astrophysics Data System (ADS)

    Campos Venuti, Lorenzo

    2011-07-01

    The sequence of ground-state energy density at finite size, eL, provides much more information than usually believed. Having at our disposal eL for short lattice sizes, we show how to reconstruct an approximate quasiparticle dispersion for any interacting model. The accuracy of this method relies on the best possible quasifree approximation to the model, consistent with the observed values of the energy eL. We also provide a simple criterion to assess whether such a quasifree approximation is valid. As a side effect, our method is able to assess whether the nature of the quasiparticles is fermionic or bosonic together with the effective boundary conditions of the model. When applied to the spin-1/2 Heisenberg model, the method produces a band of Fermi quasiparticles very close to the exact one of des Cloizeaux and Pearson. The method is further tested on a spin-1/2 Heisenberg model with explicit dimerization and on a spin-1 chain with single-ion anisotropy. A connection with the Riemann hypothesis is also pointed out.

  14. Factor demand in Swedish manufacturing industry with special reference to the demand for energy. Instantaneous adjustment models; some results

    NASA Astrophysics Data System (ADS)

    Sjoeholm, K. R.

    1981-02-01

    The dual approach to the theory of production is used to estimate factor demand functions of the Swedish manufacturing industry. Two approximations of the cost function, the translog and the generalized Leontief models, are used. The price elasticities of the factor demand do not seem to depend on the choice of model. This is at least true as to the sign pattern and as to the inputs capital, labor, total energy and other materials. Total energy is separated into solid fuels, gasoline, fuel oil, electricity and a residual. Fuel oil and electricity are found to be substitutes by both models. Capital and energy are shown to be substitutes. This implies that Swedish industry will save more energy if the capital cost can be reduced. Both models are, in the best versions, able to detect an inappropriate variable. The assumption of perfect competition on the product market, is shown to be inadequate by both models. When this assumption is relaxed, the normal substitution pattern among the inputs is resumed.

  15. High-Resolution Rotational Spectrum, Dunham Coefficients, and Potential Energy Function of NaCl.

    PubMed

    Cabezas, C; Cernicharo, J; Quintana-Lacaci, G; Peña, I; Agundez, M; Prieto, L Velilla; Castro-Carrizo, A; Zuñiga, J; Bastida, A; Alonso, J L; Requena, A

    2016-07-13

    We report laboratory spectroscopy for the first time of the J = 1-0 and J = 2-1 lines of Na(35)Cl and Na(37)Cl in several vibrational states. The hyperfine structure has been resolved in both transitions for all vibrational levels, which permit us to predict with high accuracy the hyperfine splitting of the rotational transitions of the two isotopologues at higher frequencies. The new data have been merged with all previous works at microwave, millimeter, and infrared wavelengths and fitted to a series of mass-independent Dunham parameters and to a potential energy function. The obtained parameters have been used to compute a new dipole moment function, from which the dipole moment for infrared transitions up to Δv = 8 has been derived. Frequency and intensity predictions are provided for all rovibrational transitions up to J = 150 and v = 8, from which the ALMA data of evolved stars can be modeled and interpreted.

  16. High-resolution Rotational Spectrum, Dunham Coefficients, and Potential Energy Function of NaCl

    NASA Astrophysics Data System (ADS)

    Cabezas, C.; Cernicharo, J.; Quintana-Lacaci, G.; Peña, I.; Agundez, M.; Velilla Prieto, L.; Castro-Carrizo, A.; Zuñiga, J.; Bastida, A.; Alonso, J. L.; Requena, A.

    2016-07-01

    We report laboratory spectroscopy for the first time of the J = 1-0 and J = 2-1 lines of Na35Cl and Na37Cl in several vibrational states. The hyperfine structure has been resolved in both transitions for all vibrational levels, which permit us to predict with high accuracy the hyperfine splitting of the rotational transitions of the two isotopologues at higher frequencies. The new data have been merged with all previous works at microwave, millimeter, and infrared wavelengths and fitted to a series of mass-independent Dunham parameters and to a potential energy function. The obtained parameters have been used to compute a new dipole moment function, from which the dipole moment for infrared transitions up to Δv = 8 has been derived. Frequency and intensity predictions are provided for all rovibrational transitions up to J = 150 and v = 8, from which the ALMA data of evolved stars can be modeled and interpreted.

  17. High-Resolution Rotational Spectrum, Dunham Coefficients, and Potential Energy Function of NaCl

    PubMed Central

    Cabezas, C.; Cernicharo, J.; Quintana-Lacaci, G.; Peña, I.; Agundez, M.; Prieto, L. Velilla; Castro-Carrizo, A.; Zuñiga, J.; Bastida, A.; Alonso, J. L.; Requena, A.

    2016-01-01

    We report laboratory spectroscopy for the first time of the J = 1–0 and J = 2–1 lines of Na35Cl and Na37Cl in several vibrational states. The hyperfine structure has been resolved in both transitions for all vibrational levels, which permit us to predict with high accuracy the hyperfine splitting of the rotational transitions of the two isotopologues at higher frequencies. The new data have been merged with all previous works at microwave, millimeter, and infrared wavelengths and fitted to a series of mass-independent Dunham parameters and to a potential energy function. The obtained parameters have been used to compute a new dipole moment function, from which the dipole moment for infrared transitions up to Δv = 8 has been derived. Frequency and intensity predictions are provided for all rovibrational transitions up to J = 150 and v = 8, from which the ALMA data of evolved stars can be modeled and interpreted. PMID:27733778

  18. A Method for Determining the High Energy Photon Spectrum of a Pulsed Plasma Source.

    DTIC Science & Technology

    1984-03-01

    SCHOOL OF ENOX .. UNCLRSSIF[ED C N DERSON MAR 84 AFIT/GNE/PH/84M- 1 F/0 18/4 EEEEohmhmhhEEE sfffffflllllflm|hh|h|hE|hEEK I EE|hh|h|hE|hh I...fllfllfllfllfllfll|f EEEEEE|h|hhhhE 4! S \\/ 1111 1 ’ 2.8 12.5 lil 1.0 l 112. 11111125 DI .. 111. -. ~~~~~~- T9 u.-~ ~ - j - - T -eOF S F -- F. (-,-’ OCDI 18 p...E ECT r OCT 1 I986 -.. Approved for public release; distributed unlimited. ., AFIT/GNE/PH/84M- 1 A METHOD FOR DETERMI4lIN THE HIGH ENERGY PHOTON

  19. Bio-hybrid integrated system for wide-spectrum solar energy harvesting

    SciTech Connect

    Martin, Kathleen; Erdman, Matthew; Quintana, Hope; Shelnutt, John; Nogan, John; Swartzentruber, B.; Martinez, Julio; Lavrova, Olga; Busani, Tito

    2014-03-07

    An integrated hybrid photovoltaic-thermoelectric system has been developed using multiple layers of organic photosensitizers on inorganic semiconductors in order to efficiently convert UV-visible and IR energy into electricity. The hot anode of n-type ZnO nanowires was fabricated using a thermal process on pre-seeded layer and results to be crystalline with a transmittance up to 92 % and a bandgap of 3.32 eV. The visible-UV light-active organic layer was deposited between the anode and cathode at room temperature using a layer-by-layer deposition onto ITO and ZnO and Bi2Te3 nanowires from aqueous solution. The organic layer, a cooperative binary ionic (CBI) solid is composed of oppositely charged porphyrin metal (Zn(II) and Sn(IV)(OH–)2) derivatives that are separately water soluble, but when combined form a virtually insoluble solid. The electron donor/acceptor properties (energy levels, band gaps) of the solid can be controlled by the choice of metals and the nature of the peripheral substituent groups of the porphyrin ring. The highly thermoelectric structure, which acts as a cold cathode, is composed of p-type Bi2Te3 nanowires with a thermoelectric efficiency (ZT) between ~0.7 to 1, values that are twice that expected for bulk Bi2Te3. Lastly, efficiency of the integrated device, was found to be 35 at 0.2 suns illumination and thermoelectric properties are enhanced by the charge transfer between the CBI and the Bi2Te3 is presented in terms of photo- and thermogenerated current and advantages of the low cost fabrication process is discussed.

  20. Bio-hybrid integrated system for wide-spectrum solar energy harvesting

    DOE PAGES

    Martin, Kathleen; Erdman, Matthew; Quintana, Hope; ...

    2014-03-07

    An integrated hybrid photovoltaic-thermoelectric system has been developed using multiple layers of organic photosensitizers on inorganic semiconductors in order to efficiently convert UV-visible and IR energy into electricity. The hot anode of n-type ZnO nanowires was fabricated using a thermal process on pre-seeded layer and results to be crystalline with a transmittance up to 92 % and a bandgap of 3.32 eV. The visible-UV light-active organic layer was deposited between the anode and cathode at room temperature using a layer-by-layer deposition onto ITO and ZnO and Bi2Te3 nanowires from aqueous solution. The organic layer, a cooperative binary ionic (CBI) solidmore » is composed of oppositely charged porphyrin metal (Zn(II) and Sn(IV)(OH–)2) derivatives that are separately water soluble, but when combined form a virtually insoluble solid. The electron donor/acceptor properties (energy levels, band gaps) of the solid can be controlled by the choice of metals and the nature of the peripheral substituent groups of the porphyrin ring. The highly thermoelectric structure, which acts as a cold cathode, is composed of p-type Bi2Te3 nanowires with a thermoelectric efficiency (ZT) between ~0.7 to 1, values that are twice that expected for bulk Bi2Te3. Lastly, efficiency of the integrated device, was found to be 35 at 0.2 suns illumination and thermoelectric properties are enhanced by the charge transfer between the CBI and the Bi2Te3 is presented in terms of photo- and thermogenerated current and advantages of the low cost fabrication process is discussed.« less