WorldWideScience

Sample records for energetic electron activity

  1. Relevance of southward magnetic fields in the neutral sheet to anisotropic distribution of energetic electrons and substorm activity

    International Nuclear Information System (INIS)

    Lui, A.T.Y.; Meng, C.

    1979-01-01

    The implications of southward magnetic fields at the magnetotail neutral sheet to the development of streaming anisotropy of energetic electrons and magnetospheric substorm activity are examined. Magnetic field and energetic particle measurements from the Imp 6 spacecraft, the AE index, and global auroral images from DMSP spacecraft are utilized in this study. Criteria are developed to identify events of southward magnetic fields at the neutral sheet which imply the presence of X-type magnetic neutral lines. Several features of the observations suggest that the southward magnetic fields and the implied X-type neutral lines are associated with magnetic bubbles in the neutral sheet region. It is found that the signatures of magnetic bubbles are sometimes detected in association with tailward streaming and flux enhancement of energetic electrons (47 keV< E<350keV). A cigar-shaped anisotropy in the energetic electron distribution is frequently but not always observed before the onset of tailward streaming of energetic electrons. The tailward streaming is magnetic field-aligned and occurs in the form of bursts, suggestic electrons. The tailward streaming is magnetic field-aligned and occurs in the form of bursts, suggesting that the generating process is activated somewhat quasi-periodically and is not in a steady state. Signatures of magnetic bubbles are also detected without any substantial enhancement or detectable tailward streaming of energetic electrons. By comparing Imp 6 observations with the AW index and global auroral images from DMSP spacecraft. It is found that signatures of magnetic bubbles in the neutral sheet are observed during substorms as well as during quiet geomagnetic conditions, indicating that magnetic bubbles are intrinsic features of the neutral sheet in the magnetotail regardless of substorm activity

  2. Active interrogation using energetic protons

    International Nuclear Information System (INIS)

    Morris, Christopher L.; Chung, Kiwhan; Greene, Steven J.; Hogan, Gary E.; Makela, Mark; Mariam, Fesseha; Milner, Edward C.; Murray, Matthew; Saunders, Alexander; Spaulding, Randy; Wang, Zhehui; Waters, Laurie; Wysocki, Frederick

    2010-01-01

    Energetic proton beams provide an attractive alternative when compared to electromagnetic and neutron beams for active interrogation of nuclear threats because they have large fission cross sections, long mean free paths and high penetration, and they can be manipulated with magnetic optics. We have measured time-dependent cross sections and neutron yields for delayed neutrons and gamma rays using 800 MeV and 4 GeV proton beams with a set of bare and shielded targets. The results show significant signals from both unshielded and shielded nuclear materials. Measurements of neutron energies yield suggest a signature unique to fissile material. Results are presented in this paper.

  3. The source of multi spectral energy of solar energetic electron

    Energy Technology Data Exchange (ETDEWEB)

    Herdiwijaya, Dhani [Astronomy Division and Bosscha Observatory, Faculty Mathematics and Natural Sciences, Intitute Technology of Bandung, Ganesha 10, Bandung, Indonesia 40132 dhani@as.itb.ac.id (Indonesia)

    2015-04-16

    We study the solar energetic electron distribution obtained from ACE and GOES satellites which have different altitudes and electron spectral energy during the year 1997 to 2011. The electron spectral energies were 0.038–0.315 MeV from EPAM instrument onboard ACE satellite and >2 MeV from GOES satellite. We found that the low electron energy has no correlation with high energy. In spite of we have corrected to the altitude differences. It implied that they originated from time dependent events with different sources and physical processes at the solar atmosphere. The sources of multi spectral energetic electron were related to flare and CME phenomena. However, we also found that high energetic electron comes from coronal hole.

  4. Structural, energetic and electronic properties of intercalated boron ...

    Indian Academy of Sciences (India)

    2National Institute for R&D of Isotopic and Molecular Technologies, Cluj-Napoca 400 293, Romania. MS received 8 November 2010; revised 28 March 2012. Abstract. The effects of chirality and the intercalation of transitional metal atoms inside single walled BN nano- tubes on structural, energetic and electronic properties ...

  5. Electron energetics in the expanding solar wind via Helios observations

    Czech Academy of Sciences Publication Activity Database

    Štverák, Štěpán; Trávníček, Pavel M.; Hellinger, Petr

    2015-01-01

    Roč. 120, č. 10 (2015), s. 8177-8193 ISSN 2169-9380 R&D Projects: GA ČR GAP209/12/2041; GA ČR GA15-17490S Institutional support: RVO:67985815 Keywords : solar wind * electrons energetics * transport processes Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 3.318, year: 2015

  6. On energetic prerequisites of attracting electrons

    Energy Technology Data Exchange (ETDEWEB)

    Sundholm, Dage [Department of Chemistry, POB 55 (A.I. Virtanens plats 1), FIN-00014 University of Helsinki (Finland)

    2014-06-21

    The internal reorganization energy and the zero-point vibrational energy (ZPE) of fractionally charged molecules embedded in molecular materials are discussed. The theory for isolated open quantum systems is taken as the starting point. It is shown that for isolated molecules the internal reorganization-energy function and its slope, i.e., the chemical potential of an open molecular system are monotonically decreasing functions with respect to increasing amount of negative excess charge (q) in the range of q = [0, 1]. Calculations of the ZPE for fractionally charged molecules show that the ZPE may have a minimum for fractional occupation. The calculations show that the internal reorganization energy and changes in the ZPE are of the same order of magnitude with different behavior as a function of the excess charge. The sum of the contributions might favor molecules with fractional occupation of the molecular units and partial delocalization of the excess electrons in solid-state materials also when considering Coulomb repulsion between the excess electrons. The fractional electrons are then coherently distributed on many molecules of the solid-state material forming a condensate of attracting electrons, which is crucial for the superconducting state.

  7. On energetic prerequisites of attracting electrons

    Science.gov (United States)

    Sundholm, Dage

    2014-06-01

    The internal reorganization energy and the zero-point vibrational energy (ZPE) of fractionally charged molecules embedded in molecular materials are discussed. The theory for isolated open quantum systems is taken as the starting point. It is shown that for isolated molecules the internal reorganization-energy function and its slope, i.e., the chemical potential of an open molecular system are monotonically decreasing functions with respect to increasing amount of negative excess charge (q) in the range of q = [0, 1]. Calculations of the ZPE for fractionally charged molecules show that the ZPE may have a minimum for fractional occupation. The calculations show that the internal reorganization energy and changes in the ZPE are of the same order of magnitude with different behavior as a function of the excess charge. The sum of the contributions might favor molecules with fractional occupation of the molecular units and partial delocalization of the excess electrons in solid-state materials also when considering Coulomb repulsion between the excess electrons. The fractional electrons are then coherently distributed on many molecules of the solid-state material forming a condensate of attracting electrons, which is crucial for the superconducting state.

  8. On energetic prerequisites of attracting electrons

    International Nuclear Information System (INIS)

    Sundholm, Dage

    2014-01-01

    The internal reorganization energy and the zero-point vibrational energy (ZPE) of fractionally charged molecules embedded in molecular materials are discussed. The theory for isolated open quantum systems is taken as the starting point. It is shown that for isolated molecules the internal reorganization-energy function and its slope, i.e., the chemical potential of an open molecular system are monotonically decreasing functions with respect to increasing amount of negative excess charge (q) in the range of q = [0, 1]. Calculations of the ZPE for fractionally charged molecules show that the ZPE may have a minimum for fractional occupation. The calculations show that the internal reorganization energy and changes in the ZPE are of the same order of magnitude with different behavior as a function of the excess charge. The sum of the contributions might favor molecules with fractional occupation of the molecular units and partial delocalization of the excess electrons in solid-state materials also when considering Coulomb repulsion between the excess electrons. The fractional electrons are then coherently distributed on many molecules of the solid-state material forming a condensate of attracting electrons, which is crucial for the superconducting state

  9. Transport of energetic electrons in a fully ionized hydrogen plasma

    International Nuclear Information System (INIS)

    Bai, T.

    1982-01-01

    In order to study the behavior of energetic electrons in astrophysical plasmas, I derive relationships among the Coulomb energy loss, travel distance, and pitch angle deflection due to Coulomb collisions, which hold when the Coulomb energy loss is only a small fraction of the initial energy. By using these relationships, I develop a Monte Carlo method of calculating how the pitch angle and spatial distributions of the energetic electrons change in a uniformly magnetized plasma as these electrons lose energy by Coulomb collisions, including a scheme to include the effects of the nonuniformity of the ambient magnetic field. The resulting computational framework provides an efficient and flexible system for incroporating the effects of Coulomb collisions in realistic geometries. This method is applied to a beam of monoenergetic electrons released along the magnetic field lines. Implications of the present results and future applications of this Monte Carlo method are discussed. Subject headings: hydromagnetics: plasmas: Sun: flares

  10. Pulsations of Energetic Electron Pulsations In Association With Substorm Onset

    Science.gov (United States)

    Åsnes, A.; Stadsnes, J.; Bjordal, J.; Østgaard, N.; Haaland, S.; Rosenberg, T. J.; Detrick, D. L.

    The Polar Ionospheric X-ray Imaging Experiment (PIXIE) is giving detailed images of the energetic electron precipitation when the POLAR satellite is near perigee over the Antarctica. In this area the PIXIE images have a spatial resolution of the order of 100 km, and a temporal resolution of 10 s can be obtained. In this paper we present the results of a study focusing on the onset and expansion of a substorm occuring on July 24, 1998. In this event we observe strong modulations of the energetic electron precipitation with period around 1 minute following substorm onset. The pulsations were restricted to a narrow magnetic local time sector in the pre-midnight region, about 0.5 hours wide, and showed movement towards higher latitudes and earlier lo- cal times. The event will be discussed in context of measurements from ground sta- tions and satellites in geosynchronous orbit. Precipitation of energetic electrons will be compared with VLF/ELF ground measurements. Features in the energetic elec- tron precipitation will be mapped to the magnetospheric equatorial plane by field line tracing.

  11. Transition to H-mode by energetic electrons

    International Nuclear Information System (INIS)

    Itoh, Kimitaka; Itoh, Sanae.

    1992-07-01

    Effect of the electron loss due to the toroidal ripple on an H-mode transition is studied. When energetic electrons exist in tokamaks, e.g., in the case of the current drive by lower hybrid (LH) waves, the edge electric field can show the bifurcation to the more positive value. In this state, both the electron loss and ion loss (such as loss cone loss) are reduced. The criterion for the transition is derived. Comparison with H-mode in JT-60 LH plasma shows a qualitative agreement. (author)

  12. Dual scattering foil design for poly-energetic electron beams

    International Nuclear Information System (INIS)

    Kainz, K K; Antolak, J A; Almond, P R; Bloch, C D; Hogstrom, K R

    2005-01-01

    The laser wakefield acceleration (LWFA) mechanism can accelerate electrons to energies within the 6-20 MeV range desired for therapy application. However, the energy spectrum of LWFA-generated electrons is broad, on the order of tens of MeV. Using existing laser technology, the therapeutic beam might require a significant energy spread to achieve clinically acceptable dose rates. The purpose of this work was to test the assumption that a scattering foil system designed for a mono-energetic beam would be suitable for a poly-energetic beam with a significant energy spread. Dual scattering foil systems were designed for mono-energetic beams using an existing analytical formalism based on Gaussian multiple-Coulomb scattering theory. The design criterion was to create a flat beam that would be suitable for fields up to 25 x 25 cm 2 at 100 cm from the primary scattering foil. Radial planar fluence profiles for poly-energetic beams with energy spreads ranging from 0.5 MeV to 6.5 MeV were calculated using two methods: (a) analytically by summing beam profiles for a range of mono-energetic beams through the scattering foil system, and (b) by Monte Carlo using the EGS/BEAM code. The analytic calculations facilitated fine adjustments to the foil design, and the Monte Carlo calculations enabled us to verify the results of the analytic calculation and to determine the phase-space characteristics of the broadened beam. Results showed that the flatness of the scattered beam is fairly insensitive to the width of the input energy spectrum. Also, results showed that dose calculated by the analytical and Monte Carlo methods agreed very well in the central portion of the beam. Outside the useable field area, the differences between the analytical and Monte Carlo results were small but significant, possibly due to the small angle approximation. However, these did not affect the conclusion that a scattering foil system designed for a mono-energetic beam will be suitable for a poly-energetic

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

    Science.gov (United States)

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

    2018-06-01

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

  14. A new numerical technique to design satellite energetic electron detectors

    CERN Document Server

    Tuszewski, M G; Ingraham, J C

    2002-01-01

    Energetic charged particles trapped in the magnetosphere are routinely detected by satellite instruments. However, it is generally difficult to extract quantitative energy and angular information from such measurements because the interaction of energetic electrons with matter is rather complex. Beam calibrations and Monte-Carlo (MC) simulations are often used to evaluate a flight instrument once it is built. However, rules of thumb and past experience are common tools to design the instrument in the first place. Hence, we have developed a simple numerical procedure, based on analytical probabilities, suitable for instrumental design and evaluation. In addition to the geometrical response, the contributions of surface backscattering, edge penetration, and bremsstrahlung radiation are estimated. The new results are benchmarked against MC calculations for a simple test case. Complicated effects, such as the contribution of the satellite to the instrumental response, can be estimated with the new formalism.

  15. Energy transport by energetic electrons released during solar flares. I - Thermal versus nonthermal processes

    Science.gov (United States)

    Winglee, R. M.; Dulk, G. A.; Pritchett, P. L.

    1988-01-01

    The propagation of energetic electrons through a flaring flux tube is studied in an attempt to determine how the energy of the electrons is deposited in the flux tube. One-dimensional electrostatic particle simulations are used in the present investigation. As the energetic electrons propagate into the system, a return current of ambient plasma electrons and some of the energetic electrons is drawn into the energetic electron source. It is found that, as the ambient temperature relative to the ion temperature increases above about 3, the heated return-current electrons can excite ion-sound waves.

  16. Energetics and dynamics of excess electrons in simple fluids

    International Nuclear Information System (INIS)

    Space, B.

    1992-01-01

    Excess electronic dynamical and equilibrium properties are modeled in both polarizable and nonpolarizable noble gas fluids. Explicit dynamical calculations are carried out for excess electrons in fluid helium, where excess electronic eigenstates are localized. Energetics and dynamics are considered for fluids which span the entire range of polarizability present in the rare gases. Excess electronic eigenstates and eigenvalues are calculated for fluids of helium, argon and xenon. Both equilibrium and dynamical information is obtained from the calculation of these wavefunctions. A surface hopping trajectory method for studying nonadiabatic excess electronic relaxation in condensed systems is used to explore the nonadiabatic relaxation after photoexciting an equilibrated excess electron in dense fluid helium. The different types on nonadiabatic phenomena which are important in excess electronic relaxation are surveyed. The same surface hopping trajectory method is also used to study the rapid nonadiabatic relaxation after an excess electron is injected into unperturbed fluid helium. Several distinctively different relaxation processes, characterized by their relative importance at different times during the relaxation to a localized equilibrium state, are detailed. Though the dynamical properties of excess electrons under the conditions considered here have never been studied before, the behavior is remarkably similar to that observed in both experimental and theoretical studies of electron hydration dynamics, indicating that the processes described may be very general relaxation mechanisms for localization and trapping in fluids. Additionally, ground state energies of an excess electron, e 0 , are computed as a function of solvent density using model electron-atom pseudopotentials in fluid helium, argon, and xenon. The nonuniqueness of the pseudopotential description of electron-molecule interactions is demonstrated

  17. Long-lasting injection of solar energetic electrons into the heliosphere

    Science.gov (United States)

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

    2018-05-01

    Context. The main sources of solar energetic particle (SEP) events are solar flares and shocks driven by coronal mass ejections (CMEs). While it is generally accepted that energetic protons can be accelerated by shocks, whether or not these shocks can also efficiently accelerate solar energetic electrons is still debated. In this study we present observations of the extremely widespread SEP event of 26 Dec 2013 To the knowledge of the authors, this is the widest longitudinal SEP distribution ever observed together with unusually long-lasting energetic electron anisotropies at all observer positions. Further striking features of the event are long-lasting SEP intensity increases, two distinct SEP components with the second component mainly consisting of high-energy particles, a complex associated coronal activity including a pronounced signature of a shock in radio type-II observations, and the interaction of two CMEs early in the event. Aims: The observations require a prolonged injection scenario not only for protons but also for electrons. We therefore analyze the data comprehensively to characterize the possible role of the shock for the electron event. Methods: Remote-sensing observations of the complex solar activity are combined with in situ measurements of the particle event. We also apply a graduated cylindrical shell (GCS) model to the coronagraph observations of the two associated CMEs to analyze their interaction. Results: We find that the shock alone is likely not responsible for this extremely wide SEP event. Therefore we propose a scenario of trapped energetic particles inside the CME-CME interaction region which undergo further acceleration due to the shock propagating through this region, stochastic acceleration, or ongoing reconnection processes inside the interaction region. The origin of the second component of the SEP event is likely caused by a sudden opening of the particle trap.

  18. Effects of energetic electrons on the electrodynamics in the ionosphere

    Directory of Open Access Journals (Sweden)

    A. Aksnes

    2004-01-01

    Full Text Available From the observations by the PIXIE and UVI cameras on board the Polar satellite, we derive global maps of the precipitating electron energy spectra from less than 1keV to 100keV. Based on the electron spectra, we generate instantaneous global maps of Hall and Pedersen conductances. The UVI camera provides good coverage of the lower electron energies contributing most to the Pedersen conductance, while PIXIE captures the high energy component of the precipitating electrons affecting the Hall conductance. By characterizing the energetic electrons from some tens of keV and up to about 100keV using PIXIE X-ray measurements, we will, in most cases, calculate a larger electron flux at higher energies than estimated from a simple extrapolation of derived electron spectra from UVI alone. Instantaneous global conductance maps derived with and without inclusion of PIXIE data have been implemented in the Assimilative Mapping of Ionospheric Electrodynamics (AMIE procedure, to study the effects of energetic electrons on electrodynamical parameters in the ionosphere. We find that the improved electron spectral characterization using PIXIE data most often results in a larger Hall conductance and a smaller inferred electric field. In some localized regions the increase in the Hall conductance can exceed 100%. On the contrary, the Pedersen conductance remains more or less unaffected by the inclusion of the PIXIE data. The calculated polar cap potential drop may decrease more than 10%, resulting in a reduction of the estimated Joule heating integrated over the Northern Hemisphere by up to 20%. Locally, Joule heating may decrease more than 50% in some regions. We also find that the calculated energy flux by precipitating electrons increases around 5% when including the PIXIE data. Combined with the reduction of Joule heating, this results in a decrease in the ratio between Joule heating and energy flux, sometimes exceeding 25%. An investigation of the relationship

  19. Non-Local Diffusion of Energetic Electrons during Solar Flares

    Science.gov (United States)

    Bian, N. H.; Emslie, G.; Kontar, E.

    2017-12-01

    The transport of the energy contained in suprathermal electrons in solar flares plays a key role in our understanding of many aspects of flare physics, from the spatial distributions of hard X-ray emission and energy deposition in the ambient atmosphere to global energetics. Historically the transport of these particles has been largely treated through a deterministic approach, in which first-order secular energy loss to electrons in the ambient target is treated as the dominant effect, with second-order diffusive terms (in both energy and angle) generally being either treated as a small correction or even neglected. Here, we critically analyze this approach, and we show that spatial diffusion through pitch-angle scattering necessarily plays a very significant role in the transport of electrons. We further show that a satisfactory treatment of the diffusion process requires consideration of non-local effects, so that the electron flux depends not just on the local gradient of the electron distribution function but on the value of this gradient within an extended region encompassing a significant fraction of a mean free path. Our analysis applies generally to pitch-angle scattering by a variety of mechanisms, from Coulomb collisions to turbulent scattering. We further show that the spatial transport of electrons along the magnetic field of a flaring loop can be modeled as a Continuous Time Random Walk with velocity-dependent probability distribution functions of jump sizes and occurrences, both of which can be expressed in terms of the scattering mean free path.

  20. Statistical analysis of MMS observations of energetic electron escape observed at/beyond the dayside magnetopause

    Science.gov (United States)

    Cohen, Ian J.; Mauk, Barry H.; Anderson, Brian J.; Westlake, Joseph H.; Sibeck, David G.; Turner, Drew L.; Fennell, Joseph F.; Blake, J. Bern; Jaynes, Allison N.; Leonard, Trevor W.; Baker, Daniel N.; Spence, Harlan E.; Reeves, Geoff D.; Giles, Barbara J.; Strangeway, Robert J.; Torbert, Roy B.; Burch, James L.

    2017-09-01

    Observations from the Energetic Particle Detector (EPD) instrument suite aboard the Magnetospheric Multiscale (MMS) spacecraft show that energetic (greater than tens of keV) magnetospheric particle escape into the magnetosheath occurs commonly across the dayside. This includes the surprisingly frequent observation of magnetospheric electrons in the duskside magnetosheath, an unexpected result given assumptions regarding magnetic drift shadowing. The 238 events identified in the 40 keV electron energy channel during the first MMS dayside season that exhibit strongly anisotropic pitch angle distributions indicating monohemispheric field-aligned streaming away from the magnetopause. A review of the extremely rich literature of energetic electron observations beyond the magnetopause is provided to place these new observations into historical context. Despite the extensive history of such research, these new observations provide a more comprehensive data set that includes unprecedented magnetic local time (MLT) coverage of the dayside equatorial magnetopause/magnetosheath. These data clearly highlight the common escape of energetic electrons along magnetic field lines concluded to have been reconnected across the magnetopause. While these streaming escape events agree with prior studies which show strong correlation with geomagnetic activity (suggesting a magnetotail source) and occur most frequently during periods of southward IMF, the high number of duskside events is unexpected and previously unobserved. Although the lowest electron energy channel was the focus of this study, the events reported here exhibit pitch angle anisotropies indicative of streaming up to 200 keV, which could represent the magnetopause loss of >1 MeV electrons from the outer radiation belt.

  1. Statistical analysis of MMS observations of energetic electron escape observed at/beyond the dayside magnetopause

    International Nuclear Information System (INIS)

    Cohen, Ian J.; Mauk, Barry H.; Anderson, Brian J.; Westlake, Joseph H.; Sibeck, David G.

    2017-01-01

    Here, observations from the Energetic Particle Detector (EPD) instrument suite aboard the Magnetospheric Multiscale (MMS) spacecraft show that energetic (greater than tens of keV) magnetospheric particle escape into the magnetosheath occurs commonly across the dayside. This includes the surprisingly frequent observation of magnetospheric electrons in the duskside magnetosheath, an unexpected result given assumptions regarding magnetic drift shadowing. The 238 events identified in the 40 keV electron energy channel during the first MMS dayside season that exhibit strongly anisotropic pitch angle distributions indicating monohemispheric field-aligned streaming away from the magnetopause. A review of the extremely rich literature of energetic electron observations beyond the magnetopause is provided to place these new observations into historical context. Despite the extensive history of such research, these new observations provide a more comprehensive data set that includes unprecedented magnetic local time (MLT) coverage of the dayside equatorial magnetopause/magnetosheath. These data clearly highlight the common escape of energetic electrons along magnetic field lines concluded to have been reconnected across the magnetopause. While these streaming escape events agree with prior studies which show strong correlation with geomagnetic activity (suggesting a magnetotail source) and occur most frequently during periods of southward IMF, the high number of duskside events is unexpected and previously unobserved. Although the lowest electron energy channel was the focus of this study, the events reported here exhibit pitch angle anisotropies indicative of streaming up to 200 keV, which could represent the magnetopause loss of >1 MeV electrons from the outer radiation belt.

  2. Effect of energetic electrons on combustion of premixed burner flame

    Science.gov (United States)

    Sasaki, Koichi

    2011-10-01

    In many studies of plasma-assisted combustion, authors superpose discharges onto flames to control combustion reactions. This work is motivated by more fundamental point of view. The standpoint of this work is that flames themselves are already plasmas. We irradiated microwave power onto premixed burner flame with the intention of heating electrons in it. The microwave power was limited below the threshold for a discharge. We obtained the enhancement of burning velocity by the irradiation of the microwave power, which was understood by the shortening of the flame length. At the same time, we observed the increases in the optical emission intensities of OH and CH radicals. Despite the increases in the optical emission intensities, the optical emission spectra of OH and CH were not affected by the microwave irradiation, indicating that the enhancement of the burning velocity was not attributed to the increase in the gas temperature. On the other hand, we observed significant increase in the optical emission intensity of the second positive system of molecular nitrogen, which is a clear evidence for electron heating in the premixed burner flame. Therefore, it is considered that the enhancement of the burning velocity is obtained by nonequilibrium combustion chemistry which is driven by energetic electrons. By irradiating pulsed microwave power, we examined the time constants for the increases and decreases in the optical emission intensities of N2, OH, CH, and continuum radiation.

  3. Aerosol particle charger and an SO2 reactor using energetic electrons

    International Nuclear Information System (INIS)

    Davis, R.H.

    1984-01-01

    Two properties of energetic electrons in gas, their high specific ionization and their production of radicals and other chemically active specie, have promising applications to the cleanup of flue gas from coal combustion. The copious ionization has been used in a test particle charger to electrically charge 1 and 3 μm particles for subsequent removal by electrostatic precipitation. Particle charge greater than 5 times the theoretical ionic charging value for 1 μm particles have been observed in a bi-electrode electron beam precharger in which the beam energy is matched with the electrode spacing. In another test device, pulsed streamer coronas have been used to release and to energize electrons which promote gas phase chemical reactions and remote sulfur dioxide from humid air with high efficiency. The energized electrons produce oxidant radicals and chemically active specie which convert the SO 2 into sulfuric acid mist. While reported separately here, the two applications of energetic electrons may be amenable to combination in an integrated system for the combined treatment of flue gas

  4. Pitch Angle Scattering of Energetic Electrons by Plasmaspheric Hiss Emissions

    Science.gov (United States)

    Tobita, M.; Omura, Y.; Summers, D.

    2017-12-01

    We study scattering of energetic electrons in pitch angles and kinetic energies through their resonance with plasmaspheric hiss emissions consisting of many coherent discrete whistler-mode wave packets with rising and falling frequencies [1,2,3]. Using test particle simulations, we evaluate the efficiency of scattering, which depends on the inhomogeneity ratio S of whistler mode wave-particle interaction [4]. The value of S is determined by the wave amplitude, frequency sweep rate, and the gradient of the background magnetic field. We first modulate those parameters and observe variations of pitch angles and kinetic energies of electrons with a single wave under various S values so as to obtain basic understanding. We then include many waves into the system to simulate plasmaspheric hiss emissions. As the wave packets propagate away from the magnetic equator, the nonlinear trapping potential at the resonance velocity is deformed, making a channel of gyrophase for untrapped electrons to cross the resonance velocity, and causing modulations in their pitch angles and kinetic energies. We find efficient scattering of pitch angles and kinetic energies because of coherent nonlinear wave-particle interaction, resulting in electron precipitations into the polar atmosphere. We compare the results with the bounce averaged pitch angle diffusion coefficient based on quasi-linear theory, and show that the nonlinear wave model with many coherent packets can cause scattering of resonant electrons much faster than the quasi-linear diffusion process. [1] Summers, D., Omura, Y., Nakamura, S., and C. A. Kletzing (2014), Fine structure of plasmaspheric hiss, J. Geophys. Res., 119, 9134-9149. [2] Omura, Y., Y. Miyashita, M. Yoshikawa, D. Summers, M. Hikishima, Y. Ebihara, and Y. Kubota (2015), Formation process of relativistic electron flux through interaction with chorus emissions in the Earth's inner magnetosphere, J. Geophys. Res. Space Physics, 120, 9545-9562. [3] Nakamura, S., Y

  5. Energetic electron precipitation characteristics observed from Antarctica during a flux dropout event

    Science.gov (United States)

    Clilverd, Mark A.; Cobbett, Neil; Rodger, Craig J.; Brundell, James B.; Denton, Michael H.; Hartley, David P.; Rodriguez, Juan V.; Danskin, Donald; Raita, Tero; Spanswick, Emma L.

    2013-11-01

    from two autonomous VLF radio receiver systems installed in a remote region of the Antarctic in 2012 is used to take advantage of the juxtaposition of the L = 4.6 contour, and the Hawaii-Halley, Antarctica, great circle path as it passes over thick Antarctic ice shelf. The ice sheet conductivity leads to high sensitivity to changing D region conditions, and the quasi constant L shell highlights outer radiation belt processes. The ground-based instruments observed several energetic electron precipitation events over a moderately active 24 h period, during which the outer radiation belt electron flux declined at most energies and subsequently recovered. Combining the ground-based data with low and geosynchronous orbiting satellite observations on 27 February 2012, different driving mechanisms were observed for three precipitation events with clear signatures in phase space density and electron anisotropy. Comparison between flux measurements made by Polar-orbiting Operational Environmental Satellites (POES) in low Earth orbit and by the Antarctic instrumentation provides evidence of different cases of weak and strong diffusion into the bounce loss cone, helping to understand the physical mechanisms controlling the precipitation of energetic electrons into the atmosphere. Strong diffusion events occurred as the bounce loss cone. Two events had a factor of about 3 to 10 times more >30 keV flux than was reported by POES, more consistent with strong diffusion conditions.

  6. Energetic electron injections and dipolarization events in Mercury's magnetotail: Substorm dynamics

    Science.gov (United States)

    Dewey, R. M.; Slavin, J. A.; Raines, J. M.; Imber, S.; Baker, D. N.; Lawrence, D. J.

    2017-12-01

    Despite its small size, Mercury's terrestrial-like magnetosphere experiences brief, yet intense, substorm intervals characterized by features similar to at Earth: loading/unloading of the tail lobes with open magnetic flux, dipolarization of the magnetic field at the inner edge of the plasma sheet, and, the focus of this presentation, energetic electron injection. We use the Gamma-Ray Spectrometer's high-time resolution (10 ms) energetic electron measurements to determine the relationship between substorm activity and energetic electron injections coincident with dipolarization fronts in the magnetotail. These dipolarizations were detected on the basis of their rapid ( 2 s) increase in the northward component of the tail magnetic field (ΔBz 30 nT), which typically persists for 10 s. We estimate the typical flow channel to be 0.15 RM, planetary convection speed of 750 km/s, cross-tail potential drop of 7 kV, and flux transport of 0.08 MWb for each dipolarization event, suggesting multiple simultaneous and sequential dipolarizations are required to unload the >1 MWb of magnetic flux typically returned to the dayside magnetosphere during a substorm interval. Indeed, while we observe most dipolarization-injections to be isolated or in small chains of events (i.e., 1-3 events), intervals of sawtooth-like injections with >20 sequential events are also present. The typical separation between dipolarization-injection events is 10 s. Magnetotail dipolarization, in addition to being a powerful source of electron acceleration, also plays a significant role in the substorm process at Mercury.

  7. Measurement of energetic radiation caused by thunderstorm activities by a sounding balloon and ground observation

    Science.gov (United States)

    Torii, T.

    2015-12-01

    Energetic radiation caused by thunderstorm activity is observed at various places, such as the ground, high mountain areas, and artificial satellites. In order to investigate the radiation source and its energy distribution, we measured energetic radiation by a sounding balloon, and the ground observation. On the measurement inside/above the thundercloud, we conducted a sounding observation using a radiosonde mounted two GM tubes (for gamma-rays, and for beta/gamma-rays), in addition to meteorological instruments. The balloon passed through a region of strong echoes in a thundercloud shown by radar image, at which time an increase in counting rate of the GM tube about 2 orders of magnitude occurred at the altitude from 5 km to 7.5 km. Furthermore, the counting rate of two GM tubes indicated the tendency different depending on movement of a balloon. This result suggests that the ratio for the gamma-rays (energetic photons) of the beta-rays (energetic electrons) varies according to the place in the thundercloud. Furthermore, we carried out a ground observation of the energetic gamma rays during winter thunderstorm at a coastal area facing the Sea of Japan. Two types of the energetic radiation have been observed at this time. We report the outline of these measurements and analysis in the session of the AGU meeting.

  8. Energetic Ion and Electron Irradiation of the Icy Galilean Satellites

    Science.gov (United States)

    Cooper, John F.; Johnson, Robert E.; Mauk, Barry H.; Garrett, Henry B.; Gehrels, Neil

    2001-01-01

    Galileo Orbiter measurements of energetic ions (20 keV to 100 MeV) and electrons (20-700 keV) in Jupiter's magnetosphere are used, in conjunction with the JPL electron model (less than 40 MeV), to compute irradiation effects in the surface layers of Europa, Ganymede, and Callisto. Significant elemental modifications are produced on unshielded surfaces to approximately centimeter depths in times of less than or equal to 10(exp 6) years, whereas micrometer depths on Europa are fully processed in approximately 10 years. Most observations of surface composition are limited to optical depths of approximately 1 mm, which are indirect contact with the space environment. Incident flux modeling includes Stormer deflection by the Ganymede dipole magnetic field, likely variable over that satellite's irradiation history. Delivered energy flux of approximately 8 x 10(exp 10) keV/square cm-s at Europa is comparable to total internal heat flux in the same units from tidal and radiogenic sources, while exceeding that for solar UV energies (greater than 6 eV) relevant to ice chemistry. Particle energy fluxes to Ganymede's equator and Callisto are similar at approximately 2-3 x 10(exp 8) keV/square cm-s with 5 x 10(exp 9) at Ganymede's polar cap, the latter being comparable to radiogenic energy input. Rates of change in optical reflectance and molecular composition on Europa, and on Ganymede's polar cap, are strongly driven by energy from irradiation, even in relatively young regions. Irradiation of nonice materials can produce SO2 and CO2, detected on Callisto and Europa, and simple to complex hydrocarbons. Iogenic neutral atoms and meteoroids deliver negligible energy approximately 10(exp 4-5) keV/square cm-s but impacts of the latter are important for burial or removal of irradiation products. Downward transport of radiation produced oxidants and hydrocarbons could deliver significant chemical energy into the satellite interiors for astrobiological evolution in putative sub

  9. Sunward-propagating Solar Energetic Electrons inside Multiple Interplanetary Flux Ropes

    Energy Technology Data Exchange (ETDEWEB)

    Gómez-Herrero, Raúl; Hidalgo, Miguel A.; Carcaboso, Fernando; Blanco, Juan J. [Dpto. de Física y Matemáticas, Universidad de Alcalá, E-28871 Alcalá de Henares, Madrid (Spain); Dresing, Nina; Klassen, Andreas; Heber, Bernd [Institut für Experimentelle und Angewandte Physik, University of Kiel, D-24118, Kiel (Germany); Temmer, Manuela; Veronig, Astrid [Institute of Physics/Kanzelhöhe Observatory, University of Graz, A-8010 Graz (Austria); Bučík, Radoslav [Institut für Astrophysik, Georg-August-Universität Göttingen, D-37077, Göttingen (Germany); Lario, David, E-mail: raul.gomezh@uah.es [The Johns Hopkins University, Applied Physics Laboratory, Laurel, MD 20723 (United States)

    2017-05-10

    On 2013 December 2 and 3, the SEPT and STE instruments on board STEREO-A observed two solar energetic electron events with unusual sunward-directed fluxes. Both events occurred during a time interval showing typical signatures of interplanetary coronal mass ejections (ICMEs). The electron timing and anisotropies, combined with extreme-ultraviolet solar imaging and radio wave spectral observations, are used to confirm the solar origin and the injection times of the energetic electrons. The solar source of the ICME is investigated using remote-sensing observations and a three-dimensional reconstruction technique. In situ plasma and magnetic field data combined with energetic electron observations and a flux-rope model are used to determine the ICME magnetic topology and the interplanetary electron propagation path from the Sun to 1 au. Two consecutive flux ropes crossed the STEREO-A location and each electron event occurred inside a different flux rope. In both cases, the electrons traveled from the solar source to 1 au along the longest legs of the flux ropes still connected to the Sun. During the December 2 event, energetic electrons propagated along the magnetic field, while during the December 3 event they were propagating against the field. As found by previous studies, the energetic electron propagation times are consistent with a low number of field line rotations N < 5 of the flux rope between the Sun and 1 au. The flux rope model used in this work suggests an even lower number of rotations.

  10. Markets, prices and regulation in energetic activities

    International Nuclear Information System (INIS)

    Percebois, Jacques

    2015-09-01

    The author first outlines some fundamental characteristics of the different energy world markets (oil, natural gas, coal, electricity). He outlines their availability, locations, and different main geographical areas. Then, he discusses the relationships between costs and prices in which intervene external costs, taxes, feed-in tariffs, national regulations, incentives for consumers. He discusses the issue of regulation of some energy activities, i.e. how State may or may not intervene on the markets, how competition may influence the market, how activities can thus be divided (production, transport, distribution) with implications and consequences for prices. He finally outlines concerns about the future financing of investments required to face tomorrow's needs

  11. Monitoring of the solar activity and solar energetic particles

    International Nuclear Information System (INIS)

    Akioka, Maki; Kubo, Yuki; Nagatsuma, Tsutomu; Ohtaka, Kazuhiro

    2009-01-01

    Solar activity is the source of various space weather phenomena in geospace and deep space. Solar X-ray radiation in flare, energetic particles, coronal mass ejection (CME) can cause various kind of disturbance near earth space. Therefore, detailed monitoring of the solar activity and its propagation in the interplanetary space is essential task for space weather. For example, solar energetic particle which sometimes affect spacecraft operation and manned space flight, is considered to be produced by solar flares and travelling shockwave caused by flares and CME. The research and development of monitoring technique and system for various solar activity has been an important topic of space weather forecast program in NICT. In this article, we will introduce the real time data acquisitions of STEREO and optical and radio observations of the Sun at Hiraiso Solar Observatory. (author)

  12. Low altitude observations of the energetic electrons in the outer radiation belt during isolated substorms

    International Nuclear Information System (INIS)

    Varga, L.; Venkatesan, D.; Johns Hopkins Univ., Laurel, MD; Meng, C.I.

    1985-01-01

    The low energy (1-20 keV) detector registering particles onboard the polar-orbiting low altitude (approx. 850 km) DMSP-F2 and -F3 satellites also records high energy electrons penetrating the detector walls. Thus the dynamics of this electron population at L=3.5 can be studied during isolated periods of magnetospheric substorms identified by the indices of auroral electrojet (AE), geomagnetic (Ksub(p)) and ring current (Dsub(st)). Temporal changes in the electron flux during the substorms are observed to be an additional contribution riding over the top of the pre-storm (or geomagnetically quiet-time) electron population; the duration of the interval of intensity variations is observed to be about the same as that of the enhancement of the AE index. This indicates the temporal response of the outer radiation belt to the substorm activity, since the observation was made in the ''horns'' of the outer radiation belt. The observed enhanced radiation at low altitude may associate with the instantaneous increase and/or dumping of the outer radiation belt energetic electrons during each isolated substorm activity. (author)

  13. MESSENGER observations of transient bursts of energetic electrons in Mercury's magnetosphere.

    Science.gov (United States)

    Ho, George C; Krimigis, Stamatios M; Gold, Robert E; Baker, Daniel N; Slavin, James A; Anderson, Brian J; Korth, Haje; Starr, Richard D; Lawrence, David J; McNutt, Ralph L; Solomon, Sean C

    2011-09-30

    The MESSENGER spacecraft began detecting energetic electrons with energies greater than 30 kilo-electron volts (keV) shortly after its insertion into orbit about Mercury. In contrast, no energetic protons were observed. The energetic electrons arrive as bursts lasting from seconds to hours and are most intense close to the planet, distributed in latitude from the equator to the north pole, and present at most local times. Energies can exceed 200 keV but often exhibit cutoffs near 100 keV. Angular distributions of the electrons about the magnetic field suggest that they do not execute complete drift paths around the planet. This set of characteristics demonstrates that Mercury's weak magnetic field does not support Van Allen-type radiation belts, unlike all other planets in the solar system with internal magnetic fields.

  14. Energetic electron precipitation in weak to moderate corotating interaction region-driven storms

    Science.gov (United States)

    Ødegaard, Linn-Kristine Glesnes; Tyssøy, Hilde Nesse; Søraas, Finn; Stadsnes, Johan; Sandanger, Marit Irene

    2017-03-01

    High-energy electron precipitation from the radiation belts can penetrate deep into the mesosphere and increase the production rate of NOx and HOx, which in turn will reduce ozone in catalytic processes. The mechanisms for acceleration and loss of electrons in the radiation belts are not fully understood, and most of the measurements of the precipitating flux into the atmosphere have been insufficient for estimating the loss cone flux. In the present study the electron flux measured by the NOAA POES Medium Energy Proton and Electron Detectors 0° and 90° detectors is combined together with theory of pitch angle diffusion by wave-particle interaction to quantify the electron flux lost below 120 km altitude. Using this method, 41 weak and moderate geomagnetic storms caused by corotating interaction regions during 2006-2010 are studied. The dependence of the energetic electron precipitation fluxes upon solar wind parameters and geomagnetic indices is investigated. Nine storms give increased precipitation of >˜750 keV electrons. Nineteen storms increase the precipitation of >˜300 keV electrons, but not the >˜750 keV population. Thirteen storms either do not change or deplete the fluxes at those energies. Storms that have an increase in the flux of electrons with energy >˜300 keV are characterized by an elevated solar wind velocity for a longer period compared to the storms that do not. Storms with increased precipitation of >˜750 keV flux are distinguished by higher-energy input from the solar wind quantified by the ɛ parameter and corresponding higher geomagnetic activity.

  15. The quiet time structure of energetic (35--560 keV) radiation belt electrons

    International Nuclear Information System (INIS)

    Lyons, L.R.; Williams, D.J.

    1975-01-01

    Detailed Explorer 45 equatorial observations of the quiet time structure of radiation belt electrons (35--560 keV) for 1.7approximately-less-thanLapproximately-less-than5.2 are presented. Throughout the slot region and outer regions of the plasmasphere the observed pitch angle distributions are found to agree with those expected from resonant interactions with the plasmaspheric whistler mode wave band. Coulomb collisions become the dominant loss mechanism within the inner zone. The overall two-zone structure of the observed radial profiles is found to agree with the equilibrium structure expected to result from a balance between pitch angle scattering losses and radial diffusion from an average outer zone source. This agreement suggests that the dominant quiet time source and loss mechanisms have been identified and evaluated for energetic radiation belt electrons within the plasmasphere. In the outer regions of the plasmasphere (Lapprox.5) the equilibrium structure is observed to be modified by daily flux variations associated with changes in the level of magnetic activity that occur even during relatively quiet times. Within the inner region of the plasmasphere (Lapproximately-less-than3.5), electron fluxes are decoupled from these magnetic activity variations by the long time scales (>10 days) required for pitch angle and radial diffusion. Consequently, fluxes of these electrons are observed to remain nearly constant at equilibrium levels throughout the quiet periods examined

  16. Energetic Electron Acceleration and Injection During Dipolarization Events in Mercury's Magnetotail

    Science.gov (United States)

    Dewey, Ryan M.; Slavin, James A.; Raines, Jim M.; Baker, Daniel N.; Lawrence, David J.

    2017-12-01

    Energetic particle bursts associated with dipolarization events within Mercury's magnetosphere were first observed by Mariner 10. The events appear analogous to particle injections accompanying dipolarization events at Earth. The Energetic Particle Spectrometer (3 s resolution) aboard MESSENGER determined the particle bursts are composed entirely of electrons with energies ≳ 300 keV. Here we use the Gamma-Ray Spectrometer high-time-resolution (10 ms) energetic electron measurements to examine the relationship between energetic electron injections and magnetic field dipolarization in Mercury's magnetotail. Between March 2013 and April 2015, we identify 2,976 electron burst events within Mercury's magnetotail, 538 of which are closely associated with dipolarization events. These dipolarizations are detected on the basis of their rapid ( 2 s) increase in the northward component of the tail magnetic field (ΔBz 30 nT), which typically persists for 10 s. Similar to those at Earth, we find that these dipolarizations appear to be low-entropy, depleted flux tubes convecting planetward following the collapse of the inner magnetotail. We find that electrons experience brief, yet intense, betatron and Fermi acceleration during these dipolarizations, reaching energies 130 keV and contributing to nightside precipitation. Thermal protons experience only modest betatron acceleration. While only 25% of energetic electron events in Mercury's magnetotail are directly associated with dipolarization, the remaining events are consistent with the Near-Mercury Neutral Line model of magnetotail injection and eastward drift about Mercury, finding that electrons may participate in Shabansky-like closed drifts about the planet. Magnetotail dipolarization may be the dominant source of energetic electron acceleration in Mercury's magnetosphere.

  17. Energetic Electron Acceleration, Injection, and Transport in Mercury's Magnetosphere

    Science.gov (United States)

    Dewey, R. M.; Slavin, J. A.; Raines, J. M.; Baker, D. N.; Lawrence, D. J.

    2018-05-01

    Electrons are accelerated in Mercury’s magnetotail by dipolarization events, flux ropes, and magnetic reconnection directly. Following energization, these electrons are injected close to Mercury where they drift eastward in Shabansky-like orbits.

  18. Dependence of Energetic Electron Precipitation on the Geomagnetic Index Kp and Electron Energy

    Directory of Open Access Journals (Sweden)

    Mi-Young Park

    2013-12-01

    Full Text Available It has long been known that the magnetospheric particles can precipitate into the atmosphere of the Earth. In this paper we examine such precipitation of energetic electrons using the data obtained from low-altitude polar orbiting satellite observations. We analyze the precipitating electron flux data for many periods selected from a total of 84 storm events identified for 2001-2012. The analysis includes the dependence of precipitation on the Kp index and the electron energy, for which we use three energies E1 > 30 keV, E2 > 100 keV, E3 > 300 keV. We find that the precipitation is best correlated with Kp after a time delay of < 3 hours. Most importantly, the correlation with Kp is notably tighter for lower energy than for higher energy in the sense that the lower energy precipitation flux increases more rapidly with Kp than does the higher energy precipitation flux. Based on this we suggest that the Kp index reflects excitation of a wave that is responsible for scattering of preferably lower energy electrons. The role of waves of other types should become increasingly important for higher energy, for which we suggest to rely on other indicators than Kp if one can identify such an indicator.

  19. A positive correlation between energetic electron butterfly distributions and magnetosonic waves in the radiation belt slot region

    International Nuclear Information System (INIS)

    Yang, Chang; Su, Z.; Xiao, F.; Zheng, H.

    2017-01-01

    Energetic (hundreds of keV) electrons in the radiation belt slot region have been found to exhibit the butterfly pitch angle distributions. Resonant interactions with magnetosonic and whistler-mode waves are two potential mechanisms for the formation of these peculiar distributions. Here we perform a statistical study of energetic electron pitch angle distribution characteristics measured by Van Allen Probes in the slot region during a three-year period from May 2013 to May 2016. Our results show that electron butterfly distributions are closely related to magnetosonic waves rather than to whistlermode waves. Both electron butterfly distributions and magnetosonic waves occur more frequently at the geomagnetically active times than at the quiet times. In a statistical sense, more distinct butterfly distributions usually correspond to magnetosonic waves with larger amplitudes and vice versa. The averaged magnetosonic wave amplitude is less than 5 pT in the case of normal and flat-top distributions with a butterfly index BI = 1 but reaches ~ 35–95 pT in the case of distinct butterfly distributions with BI > 1:3. For magnetosonic waves with amplitudes > 50 pT, the occurrence rate of butterfly distribution is above 80%. Our study suggests that energetic electron butterfly distributions in the slot region are primarily caused by magnetosonic waves.

  20. Electrons with continuous energy distribution from energetic heavy ion collisions

    International Nuclear Information System (INIS)

    Berenyi, D.

    1984-01-01

    The properties and origin of continuous electron spectrum emitted in high energy heavy ion collisions are reviewed. The basic processes causing the characteristic regions of the continuous spectrum are described. The contribution of electrons ejected from the target and from the projectile are investigated in detail in the cases of light and heavy projectiles. The recently recognized mechanisms, electron-capture-to-continuum (ECC) and electron-loss-to-continuum (ELC), leading to a cusp in forward direction, and their theoretical interpretations are discussed. The importance of data from ion-atom collisions in the field of atomic physics and in applications are briefly summarized. (D.Gy)

  1. ONSETS AND SPECTRA OF IMPULSIVE SOLAR ENERGETIC ELECTRON EVENTS OBSERVED NEAR THE EARTH

    International Nuclear Information System (INIS)

    Kontar, Eduard P.; Reid, Hamish A. S.

    2009-01-01

    Impulsive solar energetic electrons are often observed in the interplanetary space near the Earth and have an attractive diagnostic potential for poorly understood solar flare acceleration processes. We investigate the transport of solar flare energetic electrons in the heliospheric plasma to understand the role of transport to the observed onset and spectral properties of the impulsive solar electron events. The propagation of energetic electrons in solar wind plasma is simulated from the acceleration region at the Sun to the Earth, taking into account self-consistent generation and absorption of electrostatic electron plasma (Langmuir) waves, effects of nonuniform plasma, collisions, and Landau damping. The simulations suggest that the beam-driven plasma turbulence and the effects of solar wind density inhomogeneity play a crucial role and lead to the appearance of (1) a spectral break for a single power-law injected electron spectrum, with the spectrum flatter below the break, (2) apparent early onset of low-energy electron injection, and (3) the apparent late maximum of low-energy electron injection. We show that the observed onsets, spectral flattening at low energies, and formation of a break energy at tens of keV is the direct manifestation of wave-particle interactions in nonuniform plasma of a single accelerated electron population with an initial power-law spectrum.

  2. Test particle modeling of wave-induced energetic electron precipitation

    International Nuclear Information System (INIS)

    Chang, H.C.; Inan, U.S.

    1985-01-01

    A test particle computer model of the precipitation of radiation belt electrons is extended to compute the dynamic energy spectrum of transient electron fluxes induced by short-duration VLF wave packets traveling along the geomagnetic field lines. The model is adapted to estimate the count rate and associated spectrum of precipitated electrons that would be observed by satellite-based particle detectors with given geometric factor and orientation with respect to the magnetic field. A constant-frequency wave pulse and a lightning-induced whistler wave packet are used as examples of the stimulating wave signals. The effects of asymmetry of particle mirror heights in the two hemispheres and the atmospheric backscatter of loss cone particles on the computed precipitated fluxes are discussed

  3. ENERGETIC PHOTON AND ELECTRON INTERACTIONS WITH POSITIVE IONS

    Energy Technology Data Exchange (ETDEWEB)

    Phaneuf, Ronald A. [UNR

    2013-07-01

    The objective of this research is a deeper understanding of the complex multi-electron interactions that govern inelastic processes involving positive ions in plasma environments, such as those occurring in stellar cares and atmospheres, x-ray lasers, thermonuclear fusion reactors and materials-processing discharges. In addition to precision data on ionic structure and transition probabilities, high resolution quantitative measurements of ionization test the theoretical methods that provide critical input to computer codes used for plasma modeling and photon opacity calculations. Steadily increasing computational power and a corresponding emphasis on simulations gives heightened relevance to precise and accurate benchmark data. Photons provide a highly selective probe of the internal electronic structure of atomic and molecular systems, and a powerful means to better understand more complex electron-ion interactions.

  4. The electron-furfural scattering dynamics for 63 energetically open electronic states

    International Nuclear Information System (INIS)

    Costa, Romarly F. da; Varella, Márcio T. do N; Bettega, Márcio H. F.; Neves, Rafael F. C.; Lopes, Maria Cristina A.; Blanco, Francisco; García, Gustavo; Jones, Darryl B.

    2016-01-01

    We report on integral-, momentum transfer- and differential cross sections for elastic and electronically inelastic electron collisions with furfural (C 5 H 4 O 2 ). The calculations were performed with two different theoretical methodologies, the Schwinger multichannel method with pseudopotentials (SMCPP) and the independent atom method with screening corrected additivity rule (IAM-SCAR) that now incorporates a further interference (I) term. The SMCPP with N energetically open electronic states (N open ) at either the static-exchange (N open  ch-SE) or the static-exchange-plus-polarisation (N open  ch-SEP) approximation was employed to calculate the scattering amplitudes at impact energies lying between 5 eV and 50 eV, using a channel coupling scheme that ranges from the 1ch-SEP up to the 63ch-SE level of approximation depending on the energy considered. For elastic scattering, we found very good overall agreement at higher energies among our SMCPP cross sections, our IAM-SCAR+I cross sections and the experimental data for furan (a molecule that differs from furfural only by the substitution of a hydrogen atom in furan with an aldehyde functional group). This is a good indication that our elastic cross sections are converged with respect to the multichannel coupling effect for most of the investigated intermediate energies. However, although the present application represents the most sophisticated calculation performed with the SMCPP method thus far, the inelastic cross sections, even for the low lying energy states, are still not completely converged for intermediate and higher energies. We discuss possible reasons leading to this discrepancy and point out what further steps need to be undertaken in order to improve the agreement between the calculated and measured cross sections.

  5. The electron-furfural scattering dynamics for 63 energetically open electronic states

    Science.gov (United States)

    da Costa, Romarly F.; do N. Varella, Márcio T.; Bettega, Márcio H. F.; Neves, Rafael F. C.; Lopes, Maria Cristina A.; Blanco, Francisco; García, Gustavo; Jones, Darryl B.; Brunger, Michael J.; Lima, Marco A. P.

    2016-03-01

    We report on integral-, momentum transfer- and differential cross sections for elastic and electronically inelastic electron collisions with furfural (C5H4O2). The calculations were performed with two different theoretical methodologies, the Schwinger multichannel method with pseudopotentials (SMCPP) and the independent atom method with screening corrected additivity rule (IAM-SCAR) that now incorporates a further interference (I) term. The SMCPP with N energetically open electronic states (Nopen) at either the static-exchange (Nopen ch-SE) or the static-exchange-plus-polarisation (Nopen ch-SEP) approximation was employed to calculate the scattering amplitudes at impact energies lying between 5 eV and 50 eV, using a channel coupling scheme that ranges from the 1ch-SEP up to the 63ch-SE level of approximation depending on the energy considered. For elastic scattering, we found very good overall agreement at higher energies among our SMCPP cross sections, our IAM-SCAR+I cross sections and the experimental data for furan (a molecule that differs from furfural only by the substitution of a hydrogen atom in furan with an aldehyde functional group). This is a good indication that our elastic cross sections are converged with respect to the multichannel coupling effect for most of the investigated intermediate energies. However, although the present application represents the most sophisticated calculation performed with the SMCPP method thus far, the inelastic cross sections, even for the low lying energy states, are still not completely converged for intermediate and higher energies. We discuss possible reasons leading to this discrepancy and point out what further steps need to be undertaken in order to improve the agreement between the calculated and measured cross sections.

  6. The electron-furfural scattering dynamics for 63 energetically open electronic states

    Energy Technology Data Exchange (ETDEWEB)

    Costa, Romarly F. da [Instituto de Física “Gleb Wataghin,” Universidade Estadual de Campinas, Campinas, São Paulo 13083-859 (Brazil); Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, Santo André, São Paulo 09210-580 (Brazil); Varella, Márcio T. do N [Instituto de Física, Universidade de São Paulo, CP 66318, São Paulo, São Paulo 05315-970 (Brazil); Bettega, Márcio H. F. [Departamento de Física, Universidade Federal do Paraná, CP 19044, Curitiba, Paraná 81531-990 (Brazil); Neves, Rafael F. C. [Instituto Federal do Sul de Minas Gerais, Campus Poços de Caldas, Minas Gerais (Brazil); Departamento de Física, Universidade Federal de Juiz de Fora, Juiz de Fora, MG 36036-900 (Brazil); Lopes, Maria Cristina A. [Departamento de Física, Universidade Federal de Juiz de Fora, Juiz de Fora, MG 36036-900 (Brazil); Blanco, Francisco [Departamento de Física Atómica, Molecular y Nuclear, Universidad Complutense de Madrid, Madrid E-28040 (Spain); García, Gustavo [Instituto de Física Fundamental, CSIC, Serrano 113-bis, 28006 Madrid (Spain); Jones, Darryl B. [School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide, South Australia 5001 (Australia); and others

    2016-03-28

    We report on integral-, momentum transfer- and differential cross sections for elastic and electronically inelastic electron collisions with furfural (C{sub 5}H{sub 4}O{sub 2}). The calculations were performed with two different theoretical methodologies, the Schwinger multichannel method with pseudopotentials (SMCPP) and the independent atom method with screening corrected additivity rule (IAM-SCAR) that now incorporates a further interference (I) term. The SMCPP with N energetically open electronic states (N{sub open}) at either the static-exchange (N{sub open} ch-SE) or the static-exchange-plus-polarisation (N{sub open} ch-SEP) approximation was employed to calculate the scattering amplitudes at impact energies lying between 5 eV and 50 eV, using a channel coupling scheme that ranges from the 1ch-SEP up to the 63ch-SE level of approximation depending on the energy considered. For elastic scattering, we found very good overall agreement at higher energies among our SMCPP cross sections, our IAM-SCAR+I cross sections and the experimental data for furan (a molecule that differs from furfural only by the substitution of a hydrogen atom in furan with an aldehyde functional group). This is a good indication that our elastic cross sections are converged with respect to the multichannel coupling effect for most of the investigated intermediate energies. However, although the present application represents the most sophisticated calculation performed with the SMCPP method thus far, the inelastic cross sections, even for the low lying energy states, are still not completely converged for intermediate and higher energies. We discuss possible reasons leading to this discrepancy and point out what further steps need to be undertaken in order to improve the agreement between the calculated and measured cross sections.

  7. Energetic electron anisotropies in the magnetotail - Identification of open and closed field lines

    Science.gov (United States)

    Baker, D. N.; Stone, E. C.

    1976-01-01

    Unidirectional anisotropies in the energetic electron fluxes (E greater than or equal to about 200 keV) have been observed in the earth's magnetotail with the Caltech Electron/Isotope Spectrometer on IMP-8. The anisotropies occur during periods of enhanced fluxes and provide essential information on the topology (open or closed) of the magnetotail field lines which are associated with recently identified acceleration regions.

  8. Energetic electrons in the inner belt in 1968

    Energy Technology Data Exchange (ETDEWEB)

    West, Jr, H I; Buck, R M [California Univ., Livermore (USA). Lawrence Livermore Lab.

    1976-07-01

    Pitch-angle data were obtained by the Lawrence Livermore Laboratory's scanning, magnetic electron spectrometer on OGO 5 during its traversals of the inner belt in 1968. Data from the five lowest-energy channels 79 to 822 keV, were analyzed. The inner-belt electron injection following two storm periods was observed; the first was the mild storm of 11 June and the second the more intense storms of 31 October and 1 November. Comparisons with other data indicate that only a small Starfish residual (at > 1 MeV) still remained in the heart of the inner belt; hence, the results are indicative of the normal inner belt. The data are discussed in terms of current ideas regarding the source and loss of particles in the inner belt.

  9. Energetic electron precipitation in the aurora as determined by x-ray imaging

    International Nuclear Information System (INIS)

    Werden, S.C.

    1988-01-01

    This work examines two aspects of energetic-particle dynamics in the Earth's magnetosphere through the use of an x-ray imager flown from a stratospheric balloon in the auroral zone. The design and theory of this instrument is completely described, including the technique of image formation using an on-board microprocessor and a statistical analysis of the imaging process. Day-side energetic-electron precipitation is examined in the context of global energy dissipation during the substorm process. It is found that the relationship between events on the night side and the day side are considerably more complex that can be modeled with just a simple picture of drifting particles that induced instabilities, wave growth, and pitch-angle diffusion into the loss cone. The driving force for precipitation is probably not the presence of the energetic electrons (>30 keV) alone, but is influenced either by local effects or the less energetic component. The presence of small-scale structure, including gradients and complex motions in the precipitation region in the morning sector, suggests a local process influencing the rate of electron precipitation. The spatial and temporal evolution of a classic 5-15 second pulsating aurora during the post-breakup phase is also examined with the x-ray imager

  10. Statistical studies of energetic electrons in the outer radiation belt

    Energy Technology Data Exchange (ETDEWEB)

    Johnstone, A.D.; Rodgers, D.J.; Jones, G.H. E-mail: g.h.jones@ic.ac.uk

    1999-10-01

    The medium electron A (MEA) instrument aboard the CRRES spacecraft provided data on terrestrial radiation belt electrons in the energy range from 153 to 1582 keV, during 1990-91. These data have previously been used to produce an empirical model of the radiation belts from L=1.1 to 8.9, ordered according to 17 energy bands, 18 pitch angle bins, and 5 Kp ranges. Empirical models such as this are very valuable, but are prone to statistical fluctuations and gaps in coverage. In this study, in order to smooth the data and make it more easy to interpolate within data gaps, the pitch angle distribution at each energy in the model was fitted with a Bessel function. This provided a way to characterize the pitch angle in terms of only two parameters for each energy. It was not possible to model fluxes reliably within the loss cone because of poor statistics. The fitted distributions give an indication of the way in which pitch angle diffusion varies in the outer radiation belts. The two parameters of the Bessel function were found to vary systematically with L value, energy and Kp. Through the fitting of a simple function to these systematic variations, the number of parameters required to describe the model could be reduced drastically.

  11. Electron-Ion Intensity Dropouts in Gradual Solar Energetic Particle Events during Solar Cycle 23

    Science.gov (United States)

    Tan, Lun C.

    2017-09-01

    Since the field-line mixing model of Giacalone et al. suggests that ion dropouts cannot happen in the “gradual” solar energetic particle (SEP) event because of the large size of the particle source region in the event, the observational evidence of ion dropouts in the gradual SEP event should challenge the model. We have searched for the presence of ion dropouts in the gradual SEP event during solar cycle 23. From 10 SEP events the synchronized occurrence of ion and electron dropouts is identified in 12 periods. Our main observational facts, including the mean width of electron-ion dropout periods being consistent with the solar wind correlation scale, during the dropout period the dominance of the slab turbulence component and the enhanced turbulence power parallel to the mean magnetic field, and the ion gyroradius dependence of the edge steepness in dropout periods, are all in support of the solar wind turbulence origin of dropout events. Also, our observation indicates that a wide longitude distribution of SEP events could be due to the increase of slab turbulence fraction with the increased longitude distance from the flare-associated active region.

  12. A coordinated two-satellite study of energetic electron precipitation events

    International Nuclear Information System (INIS)

    Imhof, W.L.; Nakano, G.H.; Gaines, E.E.; Reagan, J.B.

    1975-01-01

    A new technique for studying the spatial/temporal variations of energetic electron precipitation events is investigated. Data are presented in which precipitating electrons were measured simultaneously on two coordinated polar-orbiting satellites and the bremsstrahlung produced by the electrons precipitating into the atmosphere was observed from one of the satellites. Two electron spectrometers measuring the intensities and energy spectra of electrons of >130 keV were located on the oriented satellite 1971-089A (altitude, approx. =800 km), whereas a single similar spectrometer measuring electrons of >160 keV was located on the spinning low-altitude (approx.750 km) satellite 1972-076B. The X rays of >50 keV were measured with a 50-cm 3 germanium spectrometer placed on the 1972-076B satellite. With the coordinated data a study is made of events in which large fluctuations were observed in the precipitating energetic electron intensities. In the examples presented the satellite X ray data alone demonstrate that the spatially integrated electron influx was constant in time, and when the X ray data are combined with the direct electron measurements from the two satellites, the resulting data suggest that the major features in the flux profiles were primarily spatial in nature. The combination of X ray and electron measurements from two satellites is shown to provide an important method for studying and attempting to resolve spatial and temporal effects

  13. Locating the most energetic electrons in Cassiopeia A

    DEFF Research Database (Denmark)

    Grefenstette, Brian W.; Reynolds, Stephen P.; Harrison, Fiona A.

    2015-01-01

    We present deep (>2.4 Ms) observations of the Cassiopeia A supernova remnant with NuSTAR, which operates in the 3-79 keV bandpass and is the first instrument capable of spatially resolving the remnant above 15 keV. We find that the emission is not entirely dominated by the forward shock nor...... that of the radio emission nor that of the low energy (15 keV emission an open mystery. Even at the forward shock front we find less steepening of the spectrum than expected from an exponentially cut off electron distribution with a single cutoff energy. Finally, we find that the GeV emission is not associated...

  14. Energetic particles detected by the Electron Reflectometer instrument on the Mars Global Surveyor, 1999-2006

    DEFF Research Database (Denmark)

    Delory, Gregory T.; Luhmann, Janet G.; Brain, David

    2012-01-01

    events at Mars associated with solar flares and coronal mass ejections, which includes the identification of interplanetary shocks. MGS observations of energetic particles at varying geometries between the Earth and Mars that include shocks produced by halo, limb, and backsided events provide a unique......We report the observation of galactic cosmic rays and solar energetic particles by the Electron Reflectometer instrument aboard the Mars Global Surveyor (MGS) spacecraft from May of 1999 to the mission conclusion in November 2006. Originally designed to detect low-energy electrons, the Electron...... recorded high energy galactic cosmic rays with similar to 45% efficiency. Comparisons of this data to galactic cosmic ray proton fluxes obtained from the Advanced Composition Explorer yield agreement to within 10% and reveal the expected solar cycle modulation as well as shorter timescale variations. Solar...

  15. Streaming energetic electrons in earth's magnetotail - Evidence for substorm-associated magnetic reconnection

    Science.gov (United States)

    Bieber, J. W.; Stone, E. C.

    1980-01-01

    This letter reports the results of a systematic study of streaming greater than 200 keV electrons observed in the magnetotail with the Caltech Electron/Isotope Spectrometers aboard IMP-7 and IMP-8. A clear statistical association of streaming events with southward magnetic fields, often of steep inclination, and with substorms as evidenced by the AE index is demonstrated. These results support the interpretation that streaming energetic electrons are indicative of substorm-associated magnetic reconnection in the near-earth plasma sheet.

  16. Plasma behavior during energetic electron streaming events: Further evidence for substorm-associated magnetic reconnection

    International Nuclear Information System (INIS)

    Bieber, J.W.; Stone, E.C.; Hones, E.W. Jr.; Baker, D.N.; Bame, S.J.

    1982-01-01

    A recent study showed that streaming energetic (>200 keV) electrons in Earth's magnetotail are statistically associated with southward magnetic fields and with enhancements of the AE index. It is shown here that the streaming electrons characteristically are preceded by aapprox.15 minute period of tailward plasma flow and followed by a dropout of the plasma sheet, thus demonstrating a clear statistical association between substorms and the classical signatures of magnetic reconnection and plasmoid formation. Additionally, a brief upward surge of mean electron energy preceded plasma dropout in several of the events studied, providing direct evidence of localized, reconnection-associated heating processes

  17. Inner Radiation Belt Representation of the Energetic Electron Environment: Model and Data Synthesis Using the Salammbo Radiation Belt Transport Code and Los Alamos Geosynchronous and GPS Energetic Particle Data

    Science.gov (United States)

    Friedel, R. H. W.; Bourdarie, S.; Fennell, J.; Kanekal, S.; Cayton, T. E.

    2004-01-01

    The highly energetic electron environment in the inner magnetosphere (GEO inward) has received a lot of research attention in resent years, as the dynamics of relativistic electron acceleration and transport are not yet fully understood. These electrons can cause deep dielectric charging in any space hardware in the MEO to GEO region. We use a new and novel approach to obtain a global representation of the inner magnetospheric energetic electron environment, which can reproduce the absolute environment (flux) for any spacecraft orbit in that region to within a factor of 2 for the energy range of 100 KeV to 5 MeV electrons, for any levels of magnetospheric activity. We combine the extensive set of inner magnetospheric energetic electron observations available at Los Alamos with the physics based Salammbo transport code, using the data assimilation technique of "nudging". This in effect input in-situ data into the code and allows the diffusion mechanisms in the code to interpolate the data into regions and times of no data availability. We present here details of the methods used, both in the data assimilation process and in the necessary inter-calibration of the input data used. We will present sample runs of the model/data code and compare the results to test spacecraft data not used in the data assimilation process.

  18. Understanding the Driver of Energetic Electron Precipitation Using Coordinated Multi-Satellite Measurements

    Science.gov (United States)

    Capannolo, L.; Li, W.; Ma, Q.

    2017-12-01

    Electron precipitation into the upper atmosphere is one of the important loss mechanisms in the Earth's inner magnetosphere. Various magnetospheric plasma waves (i.e., chorus, plasmaspheric hiss, electromagnetic ion cyclotron waves, etc.) play an important role in scattering energetic electrons into the loss cone, thus enhance ionization in the upper atmosphere and affect ring current and radiation belt dynamics. The present study evaluates conjunction events where low-earth-orbiting satellites (twin AeroCube-6) and near-equatorial satellites (twin Van Allen Probes) are located roughly along the same magnetic field line. By analyzing electron flux variation at various energies (> 35 keV) measured by AeroCube-6 and wave and electron measurements by Van Allen Probes, together with quasilinear diffusion theory and modeling, we determine the physical process of driving the observed energetic electron precipitation for the identified electron precipitation events. Moreover, the twin AeroCube-6 also helps us understand the spatiotemporal effect and constrain the coherent size of each electron precipitation event.

  19. Stopping powers of energetic electrons penetrating condensed matter-theory and application

    International Nuclear Information System (INIS)

    Tan Zhenyu; Xia Yueyuan

    2004-01-01

    In this review article, the motivation of studying inelastic energy loss for energetic electrons penetrating through matter and the corresponding technological importance have been outlined. The theoretical development and method for the calculation of stopping powers are described. The stopping power data tables for a group of polymers and bioorganic compounds are presented, and the application aspects of the stopping power data are briefly discussed. (authors)

  20. Analysis of detached recombining plasmas by collisonal-radiative model with energetic electron component

    International Nuclear Information System (INIS)

    Ohno, N.; Motoyama, M.; Takamura, S.

    2001-01-01

    Investigation of plasma detachment is still one of the most important subjects in the edge plasma of magnetically confined fusion devices. It was found that volumetric plasma recombination plays an essential role on reduction of particle flux in detached plasmas. The volumetric plasma recombination process has been confirmed in several diverted tokamaks and linear simulators by observing line emission from highly excited states due to three-body recombination process and continuum emission due to radiative recombination process. Electron temperature and density in the detached plasma were also evaluated from analysis of the light emission. To determine the electron temperature, the line emission spectrum is analyzed to calculate the population densities of excited levels. The population distribution among the highly excited states follows the Saha-Boltzmann distribution very closely. This implies that those states are in local thermal equilibrium (LTE) condition with free electrons in plasma so that the electron temperature can be obtained by using method of Boltzmann plot. Another method to determine the electron temperature is to compare the observed continuum spectrum with the theoretically calculated one. In our experiments using the linear diverter simulator, however, there is a clear difference for two evaluated values. One of the possible reasons is thought to be that there is a small amount of energetic electrons existing in detached recombining region. In order to evaluate the electron temperature more preciously, we need to investigate the influence of the energetic electrons on the evaluation of bulk electron temperature in a detached plasma. Collisonal-radiative (GR) model has been utilized for analyzing the light emission intensities from plasma. However, Maxwellian electron distribution function is usually assumed in the CR model. In this paper, we report a quantitative analysis of the line emission spectrum in the detached recombining plasmas by

  1. Prediction of electronically nonadiabatic decomposition mechanisms of isolated gas phase nitrogen-rich energetic salt: Guanidium-triazolate

    Energy Technology Data Exchange (ETDEWEB)

    Ghosh, Jayanta; Bhattacharya, Atanu, E-mail: atanub@ipc.iisc.ernet.in

    2016-01-13

    Highlights: • Decomposition mechanisms of model energetic salt, guanidium triazolate, are explored. • Decomposition pathways are electronically nonadiabatic. • CASPT2, CASMP2 and CASSCF methodologies are employed. • N{sub 2} and NH{sub 3} are predicted to be the most possible initial decomposition products. - Abstract: Electronically nonadiabatic decomposition pathways of guanidium triazolate are explored theoretically. Nonadiabatically coupled potential energy surfaces are explored at the complete active space self-consistent field (CASSCF) level of theory. For better estimation of energies complete active space second order perturbation theories (CASPT2 and CASMP2) are also employed. Density functional theory (DFT) with B3LYP functional and MP2 level of theory are used to explore subsequent ground state decomposition pathways. In comparison with all possible stable decomposition products (such as, N{sub 2}, NH{sub 3}, HNC, HCN, NH{sub 2}CN and CH{sub 3}NC), only NH{sub 3} (with NH{sub 2}CN) and N{sub 2} are predicted to be energetically most accessible initial decomposition products. Furthermore, different conical intersections between the S{sub 1} and S{sub 0} surfaces, which are computed at the CASSCF(14,10)/6-31G(d) level of theory, are found to play an essential role in the excited state deactivation process of guanidium triazolate. This is the first report on the electronically nonadiabatic decomposition mechanisms of isolated guanidium triazolate salt.

  2. Multipoint Observations of Energetic Particle Injections and Substorm Activity During a Conjunction Between Magnetospheric Multiscale (MMS) and Van Allen Probes

    Science.gov (United States)

    Turner, D. L.; Fennell, J. F.; Blake, J. B.; Claudepierre, S. G.; Clemmons, J. H.; Jaynes, A. N.; Leonard, T.; Baker, D. N.; Cohen, I. J.; Gkioulidou, M.; Ukhorskiy, A. Y.; Mauk, B. H.; Gabrielse, C.; Angelopoulos, V.; Strangeway, R. J.; Kletzing, C. A.; Le Contel, O.; Spence, H. E.; Torbert, R. B.; Burch, J. L.; Reeves, G. D.

    2017-11-01

    This study examines multipoint observations during a conjunction between Magnetospheric Multiscale (MMS) and Van Allen Probes on 7 April 2016 in which a series of energetic particle injections occurred. With complementary data from Time History of Events and Macroscale Interactions during Substorms, Geotail, and Los Alamos National Laboratory spacecraft in geosynchronous orbit (16 spacecraft in total), we develop new insights on the nature of energetic particle injections associated with substorm activity. Despite this case involving only weak substorm activity (maximum AE energy wave activity is also established from Van Allen Probes and MMS. Drift mapping using a simplified magnetic field model provides estimates of the dispersionless injection boundary locations as a function of universal time, magnetic local time, and L shell. The analysis reveals that at least five electron injections, which were localized in magnetic local time, preceded a larger injection of both electrons and ions across nearly the entire nightside of the magnetosphere near geosynchronous orbit. The larger ion and electron injection did not penetrate to L < 6.6, but several of the smaller electron injections penetrated to L < 6.6. Due to the discrepancy between the number, penetration depth, and complexity of electron versus ion injections, this event presents challenges to the current conceptual models of energetic particle injections.

  3. Energetics of small electron acceleration episodes in the solar corona from radio noise storm observations

    Science.gov (United States)

    James, Tomin; Subramanian, Prasad

    2018-05-01

    Observations of radio noise storms can act as sensitive probes of nonthermal electrons produced in small acceleration events in the solar corona. We use data from noise storm episodes observed jointly by the Giant Metrewave Radio Telescope (GMRT) and the Nancay Radioheliograph (NRH) to study characteristics of the nonthermal electrons involved in the emission. We find that the electrons carry 1021 to 1024 erg/s, and that the energy contained in the electrons producing a representative noise storm burst ranges from 1020 to 1023 ergs. These results are a direct probe of the energetics involved in ubiquitous, small-scale electron acceleration episodes in the corona, and could be relevant to a nanoflare-like scenario for coronal heating.

  4. Measurement of electron emission due to energetic ion bombardment in plasma source ion implantation

    Science.gov (United States)

    Shamim, M. M.; Scheuer, J. T.; Fetherston, R. P.; Conrad, J. R.

    1991-11-01

    An experimental procedure has been developed to measure electron emission due to energetic ion bombardment during plasma source ion implantation. Spherical targets of copper, stainless steel, graphite, titanium alloy, and aluminum alloy were biased negatively to 20, 30, and 40 kV in argon and nitrogen plasmas. A Langmuir probe was used to detect the propagating sheath edge and a Rogowski transformer was used to measure the current to the target. The measurements of electron emission coefficients compare well with those measured under similar conditions.

  5. Ground-based Observations and Atmospheric Modelling of Energetic Electron Precipitation Effects on Antarctic Mesospheric Chemistry

    Science.gov (United States)

    Newnham, D.; Clilverd, M. A.; Horne, R. B.; Rodger, C. J.; Seppälä, A.; Verronen, P. T.; Andersson, M. E.; Marsh, D. R.; Hendrickx, K.; Megner, L. S.; Kovacs, T.; Feng, W.; Plane, J. M. C.

    2016-12-01

    The effect of energetic electron precipitation (EEP) on the seasonal and diurnal abundances of nitric oxide (NO) and ozone in the Antarctic middle atmosphere during March 2013 to July 2014 is investigated. Geomagnetic storm activity during this period, close to solar maximum, was driven primarily by impulsive coronal mass ejections. Near-continuous ground-based atmospheric measurements have been made by a passive millimetre-wave radiometer deployed at Halley station (75°37'S, 26°14'W, L = 4.6), Antarctica. This location is directly under the region of radiation-belt EEP, at the extremity of magnetospheric substorm-driven EEP, and deep within the polar vortex during Austral winter. Superposed epoch analyses of the ground based data, together with NO observations made by the Solar Occultation For Ice Experiment (SOFIE) onboard the Aeronomy of Ice in the Mesosphere (AIM) satellite, show enhanced mesospheric NO following moderate geomagnetic storms (Dst ≤ -50 nT). Measurements by co-located 30 MHz riometers indicate simultaneous increases in ionisation at 75-90 km directly above Halley when Kp index ≥ 4. Direct NO production by EEP in the upper mesosphere, versus downward transport of NO from the lower thermosphere, is evaluated using a new version of the Whole Atmosphere Community Climate Model incorporating the full Sodankylä Ion Neutral Chemistry Model (WACCM SIC). Model ionization rates are derived from the Polar orbiting Operational Environmental Satellites (POES) second generation Space Environment Monitor (SEM 2) Medium Energy Proton and Electron Detector instrument (MEPED). The model data are compared with observations to quantify the impact of EEP on stratospheric and mesospheric odd nitrogen (NOx), odd hydrogen (HOx), and ozone.

  6. Density and temperature of energetic electrons in the Earth's magnetotail derived from high-latitude GPS observations during the declining phase of the solar cycle

    Directory of Open Access Journals (Sweden)

    M. H. Denton

    2011-10-01

    Full Text Available Single relativistic-Maxwellian fits are made to high-latitude GPS-satellite observations of energetic electrons for the period January 2006–November 2010; a constellation of 12 GPS space vehicles provides the observations. The derived fit parameters (for energies ~0.1–1.0 MeV, in combination with field-line mapping on the nightside of the magnetosphere, provide a survey of the energetic electron density and temperature distribution in the magnetotail between McIlwain L-values of L=6 and L=22. Analysis reveals the characteristics of the density-temperature distribution of energetic electrons and its variation as a function of solar wind speed and the Kp index. The density-temperature characteristics of the magnetotail energetic electrons are very similar to those found in the outer electron radiation belt as measured at geosynchronous orbit. The energetic electron density in the magnetotail is much greater during increased geomagnetic activity and during fast solar wind. The total electron density in the magnetotail is found to be strongly correlated with solar wind speed and is at least a factor of two greater for high-speed solar wind (VSW=500–1000 km s−1 compared to low-speed solar wind (VSW=100–400 km s−1. These results have important implications for understanding (a how the solar wind may modulate entry into the magnetosphere during fast and slow solar wind, and (b if the magnetotail is a source or a sink for the outer electron radiation belt.

  7. Contributions of Glycogen to Astrocytic Energetics during Brain Activation

    Science.gov (United States)

    Dienel, Gerald A.; Cruz, Nancy F.

    2014-01-01

    Glycogen is the major store of glucose in brain and is mainly in astrocytes. Brain glycogen levels in unstimulated, carefully-handled rats are 10-12 mol/g, and assuming that astrocytes account for half the brain mass, astrocytic glycogen content is twice as high. Glycogen turnover is slow under basal conditions, but it is mobilized during activation. There is no net increase in incorporation of label from glucose during activation, whereas label release from pre-labeled glycogen exceeds net glycogen consumption, which increases during stronger stimuli. Because glycogen level is restored by non-oxidative metabolism, astrocytes can influence the global ratio of oxygen to glucose utilization. Compensatory increases in utilization of blood glucose during inhibition of glycogen phosphorylase are large and approximate glycogenolysis rates during sensory stimulation. In contrast, glycogenolysis rates during hypoglycemia are low due to continued glucose delivery and oxidation of endogenous substrates; rates that preserve neuronal function in the absence of glucose are also low, probably due to metabolite oxidation. Modeling studies predict that glycogenolysis maintains a high level of glucose-6-phosphate in astrocytes to maintain feedback inhibition of hexokinase, thereby diverting glucose for use by neurons. The fate of glycogen carbon in vivo is not known, but lactate efflux from brain best accounts for the major metabolic characteristics during activation of living brain. Substantial shuttling coupled with oxidation of glycogen-derived lactate is inconsistent with available evidence. Glycogen has important roles in astrocytic energetics, including glucose sparing, control of extracellular K+ level, oxidative stress management, and memory consolidation; it is a multi-functional compound. PMID:24515302

  8. Contributions of glycogen to astrocytic energetics during brain activation.

    Science.gov (United States)

    Dienel, Gerald A; Cruz, Nancy F

    2015-02-01

    Glycogen is the major store of glucose in brain and is mainly in astrocytes. Brain glycogen levels in unstimulated, carefully-handled rats are 10-12 μmol/g, and assuming that astrocytes account for half the brain mass, astrocytic glycogen content is twice as high. Glycogen turnover is slow under basal conditions, but it is mobilized during activation. There is no net increase in incorporation of label from glucose during activation, whereas label release from pre-labeled glycogen exceeds net glycogen consumption, which increases during stronger stimuli. Because glycogen level is restored by non-oxidative metabolism, astrocytes can influence the global ratio of oxygen to glucose utilization. Compensatory increases in utilization of blood glucose during inhibition of glycogen phosphorylase are large and approximate glycogenolysis rates during sensory stimulation. In contrast, glycogenolysis rates during hypoglycemia are low due to continued glucose delivery and oxidation of endogenous substrates; rates that preserve neuronal function in the absence of glucose are also low, probably due to metabolite oxidation. Modeling studies predict that glycogenolysis maintains a high level of glucose-6-phosphate in astrocytes to maintain feedback inhibition of hexokinase, thereby diverting glucose for use by neurons. The fate of glycogen carbon in vivo is not known, but lactate efflux from brain best accounts for the major metabolic characteristics during activation of living brain. Substantial shuttling coupled with oxidation of glycogen-derived lactate is inconsistent with available evidence. Glycogen has important roles in astrocytic energetics, including glucose sparing, control of extracellular K(+) level, oxidative stress management, and memory consolidation; it is a multi-functional compound.

  9. Electron Energetics in the Martian Dayside Ionosphere: Model Comparisons with MAVEN Data

    Science.gov (United States)

    Sakai, Shotaro; Andersson, Laila; Cravens, Thomas E.; Mitchell, David L.; Mazelle, Christian; Rahmati, Ali; Fowler, Christopher M.; Bougher, Stephen W.; Thiemann, Edward M. B.; Epavier, Francis G.; hide

    2016-01-01

    This paper presents a study of the energetics of the dayside ionosphere of Mars using models and data from several instruments on board the Mars Atmosphere and Volatile EvolutioN spacecraft. In particular, calculated photoelectron fluxes are compared with suprathermal electron fluxes measured by the Solar Wind Electron Analyzer, and calculated electron temperatures are compared with temperatures measured by the Langmuir Probe and Waves experiment. The major heat source for the thermal electrons is Coulomb heating from the suprathermal electron population, and cooling due to collisional rotational and vibrational CO2 dominates the energy loss. The models used in this study were largely able to reproduce the observed high topside ionosphere electron temperatures (e.g., 3000 K at 300 km altitude) without using a topside heat flux when magnetic field topologies consistent with the measured magnetic field were adopted. Magnetic topology affects both suprathermal electron transport and thermal electron heat conduction. The effects of using two different solar irradiance models were also investigated. In particular, photoelectron fluxes and electron temperatures found using the Heliospheric Environment Solar Spectrum Radiation irradiance were higher than those with the Flare Irradiance Spectrum Model-Mars. The electron temperature is shown to affect the O2(+) dissociative recombination rate coefficient, which in turn affects photochemical escape of oxygen from Mars.

  10. Intense energetic electron flux enhancements in Mercury's magnetosphere: An integrated view with high-resolution observations from MESSENGER.

    Science.gov (United States)

    Baker, Daniel N; Dewey, Ryan M; Lawrence, David J; Goldsten, John O; Peplowski, Patrick N; Korth, Haje; Slavin, James A; Krimigis, Stamatios M; Anderson, Brian J; Ho, George C; McNutt, Ralph L; Raines, Jim M; Schriver, David; Solomon, Sean C

    2016-03-01

    The MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) mission to Mercury has provided a wealth of new data about energetic particle phenomena. With observations from MESSENGER's Energetic Particle Spectrometer, as well as data arising from energetic electrons recorded by the X-Ray Spectrometer and Gamma-Ray and Neutron Spectrometer (GRNS) instruments, recent work greatly extends our record of the acceleration, transport, and loss of energetic electrons at Mercury. The combined data sets include measurements from a few keV up to several hundred keV in electron kinetic energy and have permitted relatively good spatial and temporal resolution for many events. We focus here on the detailed nature of energetic electron bursts measured by the GRNS system, and we place these events in the context of solar wind and magnetospheric forcing at Mercury. Our examination of data at high temporal resolution (10 ms) during the period March 2013 through October 2014 supports strongly the view that energetic electrons are accelerated in the near-tail region of Mercury's magnetosphere and are subsequently "injected" onto closed magnetic field lines on the planetary nightside. The electrons populate the plasma sheet and drift rapidly eastward toward the dawn and prenoon sectors, at times executing multiple complete drifts around the planet to form "quasi-trapped" populations.

  11. Coaxial Mono-Energetic Gamma Generator for Active Interrogation

    International Nuclear Information System (INIS)

    Ludewigt, Bernhard A.; Antolak, A.J.; Henestroza, E.; Leitner, M.; Leung, K.-N.; Waldron, W.; Wilde, S.; Kwan, J.W.

    2008-01-01

    Compact mono-energetic photon sources are sought for active interrogation systems to detect shielded special nuclear materials in, for example, cargo containers, trucks and other vehicles. A prototype gamma interrogation source has been designed and built that utilizes the 11B(p,gamma)12C reaction to produce 12 MeV gamma-rays which are near the peak of the photofission cross section. In particular, the 11B(p,gamma)12C resonance at 163 kV allows the production of gammas at low proton acceleration voltages, thus keeping the design of a gamma generator comparatively small and simple. A coaxial design has been adopted with a toroidal-shaped plasma chamber surrounding a cylindrical gamma production target. The plasma discharge is driven by a 2 MHz rf-power supply (capable up to 50 kW) using a circular rf-antenna. Permanent magnets embedded in the walls of the plasma chamber generate a multi-cusp field that confines the plasma and allows higher plasma densities and lower gas pressures. About 100 proton beamlets are extracted through a slotted plasma electrode towards the target at the center of the device that is at a negative 180 kV. The target consists of LaB6 tiles that are brazed to a water-cooled cylindrical structure. The generator is designed to operate at 500 Hz with 20 mu s long pulses, and a 1percent duty factor by pulsing the ion source rf-power. A first-generation coaxial gamma source has been built for low duty factor experiments and testing.

  12. Impulse approximation treatment of electron-electron excitation and ionization in energetic ion-atom collisions

    International Nuclear Information System (INIS)

    Zouros, T.J.M.; Lee, D.H.; Sanders, J.M.; Richard, P.

    1993-01-01

    The effect of electron-electron interactions between projectile and target electrons observed in recent measurements of projectile K-shell excitation and ionization using 0 projectile Auger electron spectroscopy are analysed within the framework of the impulse approximation (IA). The IA formulation is seen to give a good account of the threshold behavior of both ionization and excitation, while providing a remarkably simple intuitive picture of such electron-electron interactions in ion-atom collisions in general. Thus, the applicability of the IA treatment is extended to cover most known processes involving such interactions including resonance transfer excitation, binary encounter electron production, electron-electron excitation and ionization. (orig.)

  13. Reconstruction of energetic electron spectra in the upper atmosphere: balloon observations of auroral X-rays coordinated with measurements from the EISCAT radar

    International Nuclear Information System (INIS)

    Olafsson, K.J.

    1990-08-01

    Energetic electron precipitation in the auroral zone has been studied using coordinated auroral X-ray measurements from balloons, altitude profiles of the ionospheric electron density measured by the EISCAT radar above the balloons, and cosmic noise absorption data from the Scandinavian riometer network. The data were obtained during the Coordinated EISCAT and Balloon Observations (CEBO) campaign in August 1984. The energy spectral variations of both the X-ray fluxes and the primary precipitating electrons were examined for two precipitation events in the morning sector. As far as reasonably can be concluded from observations of magnetic activity in the auroral zone, and from the temporal development of the energy spectra, the two precipitation events can be interpreted in the frame of present models of energetic electron precipitation on the mordning side of the auroral zone. 96 refs., 70 figs., 11 tabs

  14. Propagation of energetic electrons in the solar corona observed with LOFAR

    Science.gov (United States)

    Breitling, F.

    2017-06-01

    This work reports about new high-resolution imaging and spectroscopic observations of solar type III radio bursts at low radio frequencies in the range from 30 to 80 MHz. Solar type III radio bursts are understood as result of the beam-plasma interaction of electron beams in the corona. The Sun provides a unique opportunity to study these plasma processes of an active star. Its activity appears in eruptive events like flares, coronal mass ejections and radio bursts which are all accompanied by enhanced radio emission. Therefore solar radio emission carries important information about plasma processes associated with the Sun's activity. Moreover, the Sun's atmosphere is a unique plasma laboratory with plasma processes under conditions not found in terrestrial laboratories. Because of the Sun's proximity to Earth, it can be studied in greater detail than any other star but new knowledge about the Sun can be transfer to them. This "solar stellar connection" is important for the understanding of processes on other stars. The novel radio interferometer LOFAR provides imaging and spectroscopic capabilities to study these processes at low frequencies. Here it was used for solar observations. LOFAR, the characteristics of its solar data and the processing and analysis of the latter with the Solar Imaging Pipeline and Solar Data Center are described. The Solar Imaging Pipeline is the central software that allows using LOFAR for solar observations. So its development was necessary for the analysis of solar LOFAR data and realized here. Moreover a new density model with heat conduction and Alfvén waves was developed that provides the distance of radio bursts to the Sun from dynamic radio spectra. Its application to the dynamic spectrum of a type III burst observed on March 16, 2016 by LOFAR shows a nonuniform radial propagation velocity of the radio emission. The analysis of an imaging observation of type III bursts on June 23, 2012 resolves a burst as bright, compact region

  15. Satellite observations of energetic electron precipitation during the 1979 solar eclipse and comparisons with rocket measurements

    Science.gov (United States)

    Gaines, E. E.; Imhof, W. L.; Voss, H. D.; Reagan, J. B.

    1983-07-01

    During the solar eclipse of 26 February 1979, the P78-1 satellite passed near Red Lake, Ontario, at an altitude of about 600 km. On two consecutive orbits spanning the time of total eclipse, energetic electrons were measured with two silicon solid state detector spectrometers having excellent energy and angular resolution. Significant fluxes of precipitating electrons were observed near the path of totality. Comparisons of flux intensities and energy spectra with those measured from a Nike Orion and two Nike Tomahawk rockets launched near Red Lake before and during total eclipse give good agreement and indicate that the electron precipitation was relatively uniform for more than an hour and over a broad geographical area.

  16. Satellite observations of energetic electron precipitation during the 1979 solar eclipse and comparisons with rocket measurements

    International Nuclear Information System (INIS)

    Gaines, E.E.; Imhof, W.L.; Voss, H.D.; Reagan, J.B.

    1983-01-01

    During the solar eclipse of 26 February 1979, the P78-1 satellite passed near Red Lake, Ontario, at an altitude of approx. 600 km. On two consecutive orbits spanning the time of total eclipse, energetic electrons were measured with two silicon solid state detector spectrometers having excellent energy and angular resolution. Significant fluxes of precipitating electrons were observed near the path of totality. Comparisons of flux intensities and energy spectra with those measured from a Nike Orion and two Nike Tomahawk rockets launched near Red Lake before and during total eclipse give good agreement and indicate that the electron precipitation was relatively uniform for more than an hour and over a broad geographical area. (author)

  17. Energetic Electron Acceleration Observed by MMS in the Vicinity of an X-Line Crossing

    Science.gov (United States)

    Jaynes, A. N.; Turner, D. L.; Wilder, F. D.; Osmane, A.; Baker, D. N.; Blake, J. B.; Fennell, J. F.; Cohen, I. J.; Mauk, B. H.; Reeves, G. D.; hide

    2016-01-01

    During the first months of observations, the Magnetospheric Multiscale Fly's Eye Energetic Particle Spectrometer instrument has observed several instances of electron acceleration up to greater than 100 keV while in the vicinity of the dayside reconnection region. While particle acceleration associated with magnetic reconnection has been seen to occur up to these energies in the tail region, it had not yet been reported at the magnetopause. This study reports on observations of electron acceleration up to hundreds of keV that were recorded on 19 September 2015 around 1000 UT, in the midst of an X-line crossing. In the region surrounding the X-line, whistler-mode and broadband electrostatic waves were observed simultaneously with the appearance of highly energetic electrons which exhibited significant energization in the perpendicular direction. The mechanisms by which particles may be accelerated via reconnection-related processes are intrinsic to understanding particle dynamics among a wide range of spatial scales and plasma environments.

  18. Behaviour of superconductivity energetic characteristics in electron-doped cuprates. A simple model

    International Nuclear Information System (INIS)

    Kristoffel, N.; Rubin, P.

    2008-01-01

    A simple model to describe the energetic phase diagram of electron-doped cuprate superconductor is developed. Interband pairing operates between the UHB and the defect states created by doping and supplied by both extincting HB-s. Two defect subbands correspond to the (π,0) and (π/2,π/2) momentum regions. Extended doping quenches the bare normal state gaps (pseudogaps). Maximal transition temperature corresponds to overlapping bands ensemble intersected by the chemical potential. Illustrative results for T c , pseudo- and superconducting gaps are calculated on the whole doping scale. Major characteristic features on the phase diagram are reproduced. Anticipated manifestation of gaps doping dynamics is discussed

  19. Deflection type energy analyser for energetic electron beams in a beam-plasma system

    International Nuclear Information System (INIS)

    Michel, J.A.; Hogge, J.P.

    1988-11-01

    An energy analyser for the study of electron beam distribution functions in unmagnetized plasmas is described. This analyser is designed to avoid large electric fields which are created in multi-grid analysers and to measure directly the beam distribution function without differentiation. As an example of an application we present results on the propagation of an energetic beam (E b : 2.0 keV) in a plasma (n o : 1.10 10 cm -3 , T e : 1.4 eV) (author) 7 figs., 10 refs

  20. High-resolution transmission electron microscopy and energetics of flattened carbon nonoshells

    International Nuclear Information System (INIS)

    Bourgeois, L.N.; Bursill, L.A.

    1998-01-01

    When examined under a high-resolution transmission electron microscope, carbon soot produced alongside buckytubes in an arc-discharge is found to contain a small percentage of flattened carbon shells. These objects are shown to be small graphite flakes which eliminated their dangling bonds by terminating their edges with highly curved junctions. Ideal models for these structures are presented, and their energy estimated. The calculations show that the establishment of highly curved junctions is energetically favourable for a graphite flake in an inert atmosphere. Flattened shells also appear more stable than their 'inflated' counterparts (fullerene 'onions' and buckytubes) when the shell dimensions obey specific criteria.(authors)

  1. Two distinct energetic electron populations of different origin in the Earth's magnetotail: a Cluster case study

    Directory of Open Access Journals (Sweden)

    I. I. Vogiatzis

    2006-08-01

    Full Text Available Energetic electrons (E≥30 keV travelling along and perpendicular to the magnetic field lines have been observed in the magnetotail at L~17:00 and 22:00 MLT during the recovery phase of a storm-time substorm on 7 October 2002. Three-dimensional electron distributions of the full unit sphere obtained from the IES/RAPID sensor system demonstrated a rather complicated and random behavior of the energetic electrons. Occasionally these electrons were appearing to travel parallel, perpendicular, or in both directions, relative to the magnetic field direction, forming in this way bi-directional, perpendicular-peaked, and mixed distributions. The electron enhancements occurred while the Cluster spacecraft were on closed field lines in the central plasma sheet approaching the neutral sheet from the northern tail lobe. Magnetic field and energetic particle measurements have been used from geosynchronous and Cluster satellites, in order to describe the general context of the event and then give a possible interpretation regarding the occurrence of the electron anisotropies observed by the IES/RAPID spectrometer on board Cluster. According to geosynchronous measurements an electron dispersionless ejection is very well correlated with a dipolar re-configuration of the magnetic field. The latter fact supports the idea that electrons and, in general, particle ejections at geosynchronous altitude are directly related to electric fields arising from field dipolarization caused by current disruption. Also, having as a main objective the understanding of the way 3-D electron distributions are formed, we have analyzed electron energy spectra along and perpendicular to the magnetic field direction, demonstrating the fact that the electron population consists of two distinct components acting independently and in a random manner relative to each other. This leads to the conclusion that these two electron populations along and perpendicular to the field are

  2. Aromaticity and stability going in opposite directions: An energetic, structural, magnetic and electronic study of aminopyrimidines

    International Nuclear Information System (INIS)

    Ribeiro da Silva, Manuel A.V.; Galvão, Tiago L.P.; Rocha, Inês M.; Santos, Ana Filipa L.O.M.

    2012-01-01

    Highlights: ► Δ f H m o (cr) of 2,4-diaminopyrimidine and 2,4,6-triaminopyrimidine were obtained by combustion calorimetry. ► Sublimation thermodynamics of the compounds was studied by Knudsen effusion technique. ► Ab initio computational calculations were performed for mono-, di- and triaminopyrimidine isomers. ► Molecular energetics were correlated with several criteria of aromaticity. ► The influence of intramolecular hydrogen bonds was explored. - Abstract: The relation between molecular energetics and aromaticity was investigated for the interaction between the amino functional group and the nitrogen atoms of the pyridine and pyrimidine rings, using experimental thermodynamic techniques and computational geometries, enthalpies, chemical shifts, atomic charges and the Quantum Theory of Atoms in Molecules. 2,4-diaminopyrimidine and 2,4,6-triaminopyrimidine were studied by static bomb combustion calorimetry and Knudsen effusion technique. The derived gaseous-phase enthalpies of formation together with the enthalpies of formation of the three isomers of aminopyridine reported in the literature, were compared with the calculated computationally ones and extended to other diamino- and triaminopyrimidine isomers using the MP2/6-311++G(d,p) level of theory. The results were analyzed in terms of enthalpy of interaction between substituents and, due to the absence of meaningful stereochemical hindrance, strong inductive effects, or intramolecular hydrogen bonds according to QTAIM results, the resonance electron delocalization plays an almost exclusive role in the very exothermic enthalpies obtained. Therefore, this enthalpy of interaction was used as an experimental energetic measure of resonance effects and analyzed in terms of aromaticity. It was found that more conjugation between substituents means less aromaticity according to the magnetic (NICS) and electronic (Shannon) criteria, but more aromaticity according to the geometric (HOMA) criterion.

  3. Winter nightime ion temperatures and energetic electrons from 0go 6 plasma measurements

    International Nuclear Information System (INIS)

    Sanatani, S.; Breig, E.L.

    1981-01-01

    This paper presents and discusses ion temperature and suprathermal electron flux data acquired with the retarding potential analyzer on board the ogo 6 satellite when it was in solar eclipse. Attention is directed to measurements in the 400- to 800-km height interval between midnight and predawn in the northern winter nonpolar ionosphere. Statistical analysis of data recorded during a 1-month time span permits a decoupling of horizontal and altitude effects. A distinct longitudinal variation is observed for ion temperature above 500 km, with a significant relative enhancement over the western North Altantic Altitude distributions of ion temperature are compatible with Millstone Hill profiles within the common region of this enhancement. Large fluxes of energetic electrons are observed and extend to mush lower geomagnetic latitudes in the same longitude sector. Both a direct correlation in magnitude and a strong similarity in spatial extent are demonstrated for these ion temperature and electron flux data. The location of the limiting low-altitude boundary for observation of the electron fluxes is variable, dependent on local time and season as well as longitude. Variations in this boundary are found to be consistent with a calculated conjugate solar zenith angle of 99 0 +- 2 0 describing photoproduction of energetic electrons in the southern hemisphere. The ogo 6 data are considered to be indicative of an energy source originating in the sunlit summer hemisphere and providing heat via transport of photoelectrons to a broad but preferential segment of the winter nighttime mid-latitude ionosphere. Ions at other longitudes are without access to this energy source and cool to near the neutral temperature at heights to above 800 km inthe predawn hours

  4. Analysis of the Variation of Energetic Electron Flux with Respect to Longitude and Distance Normal to the Magnetic Equatorial Plane for Galileo Energetic Particle Detector Data

    Science.gov (United States)

    Swimm, R.; Garrett, H. B.; Jun, I.; Evans, R. W.

    2004-12-01

    In this study we examine ten-minute omni-directional averages of energetic electron data measured by the Galileo spacecraft Energetic Particle Detector (EPD). Count rates from electron channels B1, DC2, and DC3 are evaluated using a power law model to yield estimates of the differential electron fluxes from 1 MeV to 11 MeV at distances from the planet Jupiter from 8 to 28 Jupiter radii. Whereas the orbit of the Galileo spacecraft remained close to the rotational equatorial plane of Jupiter, the approximately 11 degree tilt of the magnetic axis of Jupiter relative to its rotational axis allowed the EPD instrument to sample high energy electrons at limited distances normal to the magnetic equatorial plane. We present a Fourier analysis of the semi-diurnal variation of electron radiation with longitude. We also develop a model of the electron flux with respect to distance normal to the magnetic equatorial plane as a function of the distance from Jupiter.

  5. Long-lasting solar energetic electron injection during the 26 Dec 2013 widespread SEP event

    Science.gov (United States)

    Dresing, N.; Klassen, A.; Temmer, M.; Gomez-Herrero, R.; Heber, B.; Veronig, A.

    2017-12-01

    The solar energetic particle (SEP) event on 26 Dec 2013 was detected all around the Sun by the two STEREO spacecraft and close-to-Earth observers. While the two STEREOs were separated by 59 degrees and situated at the front side of the associated large coronal event, it was a backside-event for Earth. Nevertheless, significant and long-lasting solar energetic electron anisotropies together with long rise times were observed at all three viewpoints, pointing to an extended electron injection. Although the CME-driven shock appears to account for the SEP event at a first glance a more detailed view reveals a more complex scenario: A CME-CME interaction takes place during the very early phase of the SEP event. Furthermore, four hours after the onset of the event, a second component is measured at all three viewpoints on top of the first SEP increase, mainly consisting of high energy particles. We find that the CME-driven shock alone can hardly account for the observed SEP event in total but a trapping scenario together with ongoing particle acceleration is more likely.

  6. Fluxes of energetic protons and electrons measured on board the Oersted satellite

    Directory of Open Access Journals (Sweden)

    J. Cabrera

    2005-11-01

    Full Text Available The Charged Particle Detector (CPD on board the Oersted satellite (649 km perigee, 865 km apogee and 96.48° inclination currently measures energetic protons and electrons. The measured peak fluxes of E>1 MeV electrons are found to confirm the predictions of AE8-MAX, though they occur at a geographical position relatively shifted in the SAA. The fluxes of protons are one order of magnitude higher than the predictions of AP8-MAX in the energy range 20-500 MeV. This huge discrepancy between AP8 and recent measurements in LEO was already noticed and modelled in SAMPEX/PSB97 and TPM-1 models. Nevertheless some other LEO measurements such as PROBA and CORONA-F result in flux values in good agreement with AP8 within a factor 2. The anisotropy of the low-altitude proton flux, combined with measurement performed on board three-axis stabilised satellites, has been suspected to be one possible source of the important discrepancies observed by different missions. In this paper, we evaluate the effect of anisotropy on flux measurements conducted using the CPD instruments. On the basis of the available data, we confirm the inaccuracy of AP8 at LEO and suggest methods to improve the analysis of data in future flux measurements of energetic protons at low altitudes.

  7. Solar cyclic behavior of trapped energetic electrons in Earth's inner radiation belt

    Science.gov (United States)

    Abel, Bob; Thorne, Richard M.

    1994-10-01

    Magnetic electron spectrometer data from six satellites (OV3-3, OV1-14, OGO 5, S3-2, S3-3, and CRRES) have been used to study long-term (1966-1991) behavior of trapped energetic electrons in the inner radiation belt. Comparison of the observed energy spectra at L equal to or greater than 1.35 for different phases of the solar cycle reveals a clear trend toward enhanced fluxes during periods of solar maximum for energies below a few hundred keV; we suggest that this is caused by an increase in the rate of inward radial diffusion from a source at higher L. In contrast, for L less than 1.30, where atmospheric collisions become increasingly important, the electron flux is reduced during solar maximum; we attribute this to the expected increase in upper atmospheric densities. The electron flux above 1 MeV exhibits a systematic decay beyond 1979 to values well below the current NASA AE-8 model. This indicates that the natural background of high-energy electrons has previously been overestimated due to the long lasting presence of electrons produced by nuclear detonations in the upper atmosphere in the late 1950s and early 1960s.

  8. MMS FEEPS Energetic Electron Microinjection Observations During 2015 Through October 2017

    Science.gov (United States)

    Fennell, J. F.; Turner, D. L.; Lemon, C.; Kavosi, S.; Spence, H. E.; Jaynes, A. N.; Blake, J. B.; Clemmons, J. H.; Baker, D. N.; Mauk, B.; Burch, J. L.; Cohen, I. J.

    2017-12-01

    During MMS traversals of the midnight to dusk local time regions energetic electron data showed many clusters of electron injections we call microinjections because of their short duration signatures. These microinjections of 50-400 keV electrons have energy dispersion signatures indicating that they gradient and curvature drifted from earlier local times. Multiple clusters of microinjection occurred during these traversals. We show detailed results from some microinjections taken with burst mode data. These high temporal resolution data showed that the electrons in the microinjections were trapped and had bidirectional field-aligned angular distributions. Drift calculations constrained by the observed electron dispersion times indicate the electrons had drifted from near the magnetopause hours earlier in local time. They were not observed in the midnight through pre-noon regions in 2015-2016. The 2015-2016 observations were limited to altitudes of 9 to 12 Re because the MMS apogee was 12 Re then. In March 2017, the MMS apogee was raised to 25 Re and we will show how these later microinjection observations compare to the earlier ones. These injection clusters are a new phenomenon in this region of the magnetosphere and with the higher orbit we will observe how close to the magnetopause they exist and possibly traverse the source regions. We will provide statistics on the occurrence of the injections and discuss possible sources and implications.

  9. DROPOUT OF DIRECTIONAL ELECTRON INTENSITIES IN LARGE SOLAR ENERGETIC PARTICLE EVENTS

    Energy Technology Data Exchange (ETDEWEB)

    Tan, Lun C. [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); Reames, Donald V., E-mail: ltan@umd.edu [Institute for Physical Science and Technology, University of Maryland, College Park, MD 20742 (United States)

    2016-01-10

    In the “gradual” solar energetic particle (SEP) event during solar cycle 23 we have observed the dispersionless modulation (“dropout”) in directional intensities of nonrelativistic electrons. The average duration of dropout periods is ∼0.8 hr, which is consistent with the correlation scale of solar wind turbulence. During the dropout period electrons could display scatter-free transport in an intermittent way. Also, we have observed a decrease in the anisotropic index of incident electrons with increasing electron energy (E{sub e}), while the index of scattered/reflected electrons is nearly independent of E{sub e}. We hence perform an observational examination of the correlation between the anisotropic index of low-energy scattered/reflected electrons and the signature of the locally measured solar wind turbulence in the dissipation range, which is responsible for resonant scattering of nonrelativistic electrons. Since during the dropout period the slab turbulence fraction is dominant (0.8 ± 0.1), we pay close attention to the effect of slab fraction on the correlation examined. Our observation is consistent with the simulation result that in the dominance of the slab turbulence component there should exist a dispatched structure of magnetic flux tubes, along which electrons could be transported in a scatter-free manner. Since a similar phenomenon is exhibited in the “impulsive” SEP event, electron dropout should be a transport effect. Therefore, being different from most ion dropout events, which are due to a compact flare source, the dropout of directional electron intensities should be caused by the change of turbulence status in the solar wind.

  10. DROPOUT OF DIRECTIONAL ELECTRON INTENSITIES IN LARGE SOLAR ENERGETIC PARTICLE EVENTS

    International Nuclear Information System (INIS)

    Tan, Lun C.; Reames, Donald V.

    2016-01-01

    In the “gradual” solar energetic particle (SEP) event during solar cycle 23 we have observed the dispersionless modulation (“dropout”) in directional intensities of nonrelativistic electrons. The average duration of dropout periods is ∼0.8 hr, which is consistent with the correlation scale of solar wind turbulence. During the dropout period electrons could display scatter-free transport in an intermittent way. Also, we have observed a decrease in the anisotropic index of incident electrons with increasing electron energy (E e ), while the index of scattered/reflected electrons is nearly independent of E e . We hence perform an observational examination of the correlation between the anisotropic index of low-energy scattered/reflected electrons and the signature of the locally measured solar wind turbulence in the dissipation range, which is responsible for resonant scattering of nonrelativistic electrons. Since during the dropout period the slab turbulence fraction is dominant (0.8 ± 0.1), we pay close attention to the effect of slab fraction on the correlation examined. Our observation is consistent with the simulation result that in the dominance of the slab turbulence component there should exist a dispatched structure of magnetic flux tubes, along which electrons could be transported in a scatter-free manner. Since a similar phenomenon is exhibited in the “impulsive” SEP event, electron dropout should be a transport effect. Therefore, being different from most ion dropout events, which are due to a compact flare source, the dropout of directional electron intensities should be caused by the change of turbulence status in the solar wind

  11. Effect of energetic electrons on dust charging in hot cathode filament discharge

    Science.gov (United States)

    Kakati, B.; Kausik, S. S.; Saikia, B. K.; Bandyopadhyay, M.

    2011-03-01

    The effect of energetic electrons on dust charging for different types of dust is studied in hydrogen plasma. The hydrogen plasma is produced by hot cathode filament discharge method in a dusty plasma device. A full line cusped magnetic field cage is used to confine the plasma elements. To study the plasma parameters for various discharge conditions, a cylindrical Langmuir probe having 0.15 mm diameter and 10.0 mm length is used. An electronically controlled dust dropper is used to drop the dust particles into the plasma. For different discharge conditions, the dust current is measured using a Faraday cup connected to an electrometer. The effect of secondary emission as well as discharge voltage on charging of dust grains in hydrogen plasma is studied with different dust.

  12. Effect of energetic electrons on dust charging in hot cathode filament discharge

    International Nuclear Information System (INIS)

    Kakati, B.; Kausik, S. S.; Saikia, B. K.; Bandyopadhyay, M.

    2011-01-01

    The effect of energetic electrons on dust charging for different types of dust is studied in hydrogen plasma. The hydrogen plasma is produced by hot cathode filament discharge method in a dusty plasma device. A full line cusped magnetic field cage is used to confine the plasma elements. To study the plasma parameters for various discharge conditions, a cylindrical Langmuir probe having 0.15 mm diameter and 10.0 mm length is used. An electronically controlled dust dropper is used to drop the dust particles into the plasma. For different discharge conditions, the dust current is measured using a Faraday cup connected to an electrometer. The effect of secondary emission as well as discharge voltage on charging of dust grains in hydrogen plasma is studied with different dust.

  13. An Energetic Electron Flux Dropout Due to Magnetopause Shadowing on 1 June 2013

    Science.gov (United States)

    Kang, Suk-Bin; Fok, Mei-Ching; Komar, Colin; Glocer, Alex; Li, Wen; Buzulukova, Natalia

    2018-02-01

    We examine the mechanisms responsible for the dropout of energetic electron flux during 31 May to 1 June 2013 using Van Allen Probe (Radiation Belt Storm Probes (RBSP)) electron flux data and simulations with the Comprehensive Inner Magnetosphere-Ionosphere (CIMI) model. During the storm main phase, L-shells at RBSP locations are greater than 8, which are connected to open drift shells. Consequently, diminished electron fluxes were observed over a wide range of energies. The combination of drift shell splitting, magnetopause shadowing, and drift loss all results in butterfly electron pitch angle distributions (PADs) at the nightside. During storm sudden commencement, RBSP observations display electron butterfly PADs over a wide range of energies. However, it is difficult to determine whether there are butterfly PADs during the storm main phase since the maximum observable equatorial pitch angle from RBSP is not larger than 40° during this period. To investigate the causes of the dropout, the CIMI model is used as a global 4-D kinetic inner magnetosphere model. The CIMI model reproduces the dropout with very similar timing and flux levels and PADs along the RBSP trajectory for 593 keV. Furthermore, the CIMI simulation shows butterfly PADs for 593 keV during the storm main phase. Based on comparison of observations and simulations, we suggest that the dropout during this event mainly results from magnetopause shadowing.

  14. Observations of field-aligned energetic electron and ion distributions near the magnetopause at geosynchronous orbit

    International Nuclear Information System (INIS)

    Korth, A.; Kremser, G.; Daly, P.W.; Amata, E.

    1982-01-01

    On August 28, 1978, the dayside magnetopause crossed the geosynchronous satellite GEOS 2 several times during a geomagnetically disturbed period, and clear signatures of the interconnection of field lines through the magnetopause were observed. The MPAE particle spectrometer provided high time resolution observations of the distribution of energetic electrons (E>22 keV) and ions (E>27 keV). Magnetometer data were used to determine the location of GEOS 2 relative to the magnetopause. The pitch angle distributions of ions and electrons were found to be strongly asymmetric with respect to 90 0 , and the asymmetries have been interpreted in terms of field-aligned particle streaming. Evidence is provided for the first time for electron streaming inside the magnetopause which continues for many bounce periods. It is concluded that magnetospheric field lines opened, at least for brief time intervals, as a consequence of interconnection with magnetosheath field lines. Comparisons of electron spectra provide evidence that the streaming electrons observed in the magnetosheath originate in the magnetosphere

  15. Reconstruction of energetic electron spectra in the upper atmosphere: balloon observations of auroral X-rays coordinated with measurements from the Eiscat radar

    International Nuclear Information System (INIS)

    Olafsson, K.J.

    1990-01-01

    Energetic electron precipitation in the auroral zone has been studied using coordinated auroral X-ray measurements from balloons, altitude profiles of the ionospheric electron density measured by the EISCAT radar above the balloons, and cosmic noise absorption data from the Scandinavian riometer network. The data were obtained during the coordinated EISCAT and balloon observation campaign in August 1984. A method by which an estimate of the energy spectrum of precipitating energetic electrons can be obtained from balloon measurements of bremsstrahlung X-rays is described. The energy spectral variation of both the X-ray fluxes and the primary precipitating electrons were examined for two precipitation events in the morning sector. As far as reasonably can be concluded from observations of magnetic activity in the auroral zone, and from the temporal development of the energy spectra, the two precipitation events can be interpreted in the frame of present models of energetic electron precipitation on the morning side of the auroral zone. 96 refs

  16. Quantitative study of substorm-associated VLF phase anomalies and precipitating energetic electrons on November 13, 1979

    International Nuclear Information System (INIS)

    Kikuchi, T.; Evans, D.S.

    1983-01-01

    The phase anomalies associated with substorms are observed on VLF signals propagating on transauroral paths (transmitters at OMEGA-ALDRA (13.6 kHz), GBR (16.0 kHz), and OMEGA--NORTH DAKOTA (13.6 kHz)) which were continually received at Inubo, Japan, during the events on November 13, 1979. Detailed comparisons are made between these phase anomalies and geomagnetic bays, and quantitative relations are obtained with precipitating energetic electrons (E>30, E>100, and E>300 keV) detected on board the TIROS-N and NOAA 6 satellites. It is concluded that two types of VLF phase anomalies exist which, in turn, are associated with two phases in the history of energetic electron precipitation into the atmosphere. The first type of phase anomaly is associated with direct injection of energetic electrons into the outer magnetosphere and atmosphere which, in turn, is completely correlated in time with development of the auroral electrojet current system. The second type arises from energetic electrons which subsequently precipitate from a trapped electron population and has a delayed onset and prolonged duration. An excellent quantitative correlation is obtained between the logarithm of the electron flux and the magnitude of the phase anomaly on the OMEGA-ALDRA signal. From the local time characteristics of this quantitative relation it is deduced that the electrons with E>300 keV are the main source of D region ionization responsible for the VLF phase anomaly

  17. InP and InAs nanowires hetero- and homojunctions: energetic stability and electronic properties.

    Science.gov (United States)

    Dionízio Moreira, M; Venezuela, P; Miwa, R H

    2010-07-16

    We performed an ab initio total energy investigation, within the density functional theory, of the energetic stability and the electronic properties of hydrogenated InAs/InP nanowire (NW) heterojunctions, as well as InAs and InP homojunctions composed of different structural arrangements, zinc-blend (zb) and wurtzite (w). For InAs/InP NW heterojunctions our results indicate that w and zb NW heterojunctions are quite similar, energetically, for thin NWs. We also examined the robustness of the abrupt interface through an atomic swap at the InAs/InP interface. Our results support the formation of abrupt (non-abrupt) interfaces in w (zb) InAs/InP heterojunctions. Concerning InAs/InP NW-SLs, our results indicate a type-I band alignment, with the energy barrier at the InP layers, in accordance with experimental works. For InAs or InP zb/w homojunctions, we also found a type-I band alignment for thin NWs, however, on increasing the NW diameter both InAs and InP homojunctions exhibit a type-II band alignment.

  18. InP and InAs nanowires hetero- and homojunctions: energetic stability and electronic properties

    International Nuclear Information System (INIS)

    Dionizio Moreira, M; Venezuela, P; Miwa, R H

    2010-01-01

    We performed an ab initio total energy investigation, within the density functional theory, of the energetic stability and the electronic properties of hydrogenated InAs/InP nanowire (NW) heterojunctions, as well as InAs and InP homojunctions composed of different structural arrangements, zinc-blend (zb) and wurtzite (w). For InAs/InP NW heterojunctions our results indicate that w and zb NW heterojunctions are quite similar, energetically, for thin NWs. We also examined the robustness of the abrupt interface through an atomic As↔P swap at the InAs/InP interface. Our results support the formation of abrupt (non-abrupt) interfaces in w (zb) InAs/InP heterojunctions. Concerning InAs/InP NW-SLs, our results indicate a type-I band alignment, with the energy barrier at the InP layers, in accordance with experimental works. For InAs or InP zb/w homojunctions, we also found a type-I band alignment for thin NWs, however, on increasing the NW diameter both InAs and InP homojunctions exhibit a type-II band alignment.

  19. Computational Model of D-Region Ion Production Caused by Energetic Electron Precipitations Based on General Monte Carlo Transport Calculations

    Science.gov (United States)

    Kouznetsov, A.; Cully, C. M.

    2017-12-01

    During enhanced magnetic activities, large ejections of energetic electrons from radiation belts are deposited in the upper polar atmosphere where they play important roles in its physical and chemical processes, including VLF signals subionospheric propagation. Electron deposition can affect D-Region ionization, which are estimated based on ionization rates derived from energy depositions. We present a model of D-region ion production caused by an arbitrary (in energy and pitch angle) distribution of fast (10 keV - 1 MeV) electrons. The model relies on a set of pre-calculated results obtained using a general Monte Carlo approach with the latest version of the MCNP6 (Monte Carlo N-Particle) code for the explicit electron tracking in magnetic fields. By expressing those results using the ionization yield functions, the pre-calculated results are extended to cover arbitrary magnetic field inclinations and atmospheric density profiles, allowing ionization rate altitude profile computations in the range of 20 and 200 km at any geographic point of interest and date/time by adopting results from an external atmospheric density model (e.g. NRLMSISE-00). The pre-calculated MCNP6 results are stored in a CDF (Common Data Format) file, and IDL routines library is written to provide an end-user interface to the model.

  20. Formation, Energetics, and Electronic Properties of Graphene Monolayer and Bilayer Doped with Heteroatoms

    Directory of Open Access Journals (Sweden)

    Yoshitaka Fujimoto

    2015-01-01

    Full Text Available Doping with heteroatoms is one of the most effective methods to tailor the electronic properties of carbon nanomaterials such as graphene and carbon nanotubes, and such nanomaterials doped with heteroatom dopants might therefore provide not only new physical and chemical properties but also novel nanoelectronics/optoelectronics device applications. The boron and nitrogen are neighboring elements to carbon in the periodic table, and they are considered to be good dopants for carbon nanomaterials. We here review the recent work of boron and nitrogen doping effects into graphene monolayer as well as bilayer on the basis of the first-principles electronic structure calculations in the framework of the density-functional theory. We show the energetics and the electronic properties of boron and nitrogen defects in graphene monolayer and bilayer. As for the nitrogen doping, we further discuss the stabilities, the growth processes, and the electronic properties associated with the plausible nitrogen defect formation in graphene which is suggested by experimental observations.

  1. Average energetic ion flux variations associated with geomagnetic activity from EPIC/STICS on Geotail

    Science.gov (United States)

    Christon, S. P.; Gloeckler, G.; Eastman, T. E.; McEntire, R. W.; Roelef, E. C.; Lui, A. T. Y.; Williams, D. J.; Frank, L. A.; Paterson, W. R.; Kokubun, S.; hide

    1996-01-01

    The magnetotail ion flux measurements from the Geotail spacecraft are analyzed both with and without the application of selection criteria that identify the plasma regime in which an observation is obtained. The different results are compared with each other. The initial results on the changes of energetic ion flux and composition correlated to average substorm activity in different magnetotail plasma regimes are discussed. The energetic ions are measured using the energetic particles and ion composition (EPIC) experiment and the suprathermal ion composition spectrometer (STICS). The plasma, wave and field instruments of the Geotail satellite were used to identify the principle magnetotail plasma regimes of plasma sheet, lobe, and magnetospheric boundary layer, as well as the magnetosheath and solar wind. Energetic O and H ions were observed in all the plasma regimes.

  2. Radio wave dissipation in turbulent auroral plasma during the precipitation of energetic electrons

    International Nuclear Information System (INIS)

    Mishin, E.V.; Luk'ianova, L.N.; Makarenko, S.F.; Atamaniuk, B.M.

    1992-01-01

    The results of the theoretical analysis of anomalous (collisionless) radio wave absorption in the turbulent auroral ionosphere during the intrusion of energetic electrons (i.e., in aurorae) are presented. The implications of the plasma turbulent layer (PTL) theory are used. It is shown that the dissipation of radio waves with frequencies much higher than the plasma frequency is caused by the nonlinear (combined) scattering in turbulent plasma of the PTL. In the auroral electrojet layer the principal dissipative process for the radio waves with frequencies close to the plasma frequency is O-Z transformation on the field-aligned, small-scale density fluctuations. The typical dissipation decrements are estimated. 26 refs

  3. The Role of Diffusion in the Transport of Energetic Electrons during Solar Flares

    Energy Technology Data Exchange (ETDEWEB)

    Bian, Nicolas H.; Kontar, Eduard P. [School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, Scotland (United Kingdom); Emslie, A. Gordon, E-mail: nicolas.bian@glasgow.gla.ac.uk, E-mail: emslieg@wku.edu [Department of Physics and Astronomy, Western Kentucky University, Bowling Green, KY 42101 (United States)

    2017-02-01

    The transport of the energy contained in suprathermal electrons in solar flares plays a key role in our understanding of many aspects of flare physics, from the spatial distributions of hard X-ray emission and energy deposition in the ambient atmosphere to global energetics. Historically the transport of these particles has been largely treated through a deterministic approach, in which first-order secular energy loss to electrons in the ambient target is treated as the dominant effect, with second-order diffusive terms (in both energy and angle) generally being either treated as a small correction or even neglected. Here, we critically analyze this approach, and we show that spatial diffusion through pitch-angle scattering necessarily plays a very significant role in the transport of electrons. We further show that a satisfactory treatment of the diffusion process requires consideration of non-local effects, so that the electron flux depends not just on the local gradient of the electron distribution function but on the value of this gradient within an extended region encompassing a significant fraction of a mean free path. Our analysis applies generally to pitch-angle scattering by a variety of mechanisms, from Coulomb collisions to turbulent scattering. We further show that the spatial transport of electrons along the magnetic field of a flaring loop can be modeled rather effectively as a Continuous Time Random Walk with velocity-dependent probability distribution functions of jump sizes and occurrences, both of which can be expressed in terms of the scattering mean free path.

  4. Altered expression of mitochondrial electron transport chain proteins and improved myocardial energetic state during late ischemic preconditioning

    NARCIS (Netherlands)

    J.A. Cabrera (Jesús); E.A. Ziemba (Elizabeth); L.H. Colbert (Lisa); L.B. Anderson (Lorraine); W.J. Sluiter (Wim); D.J.G.M. Duncker (Dirk); T.A. Butterick (Tammy); J. Sikora (Joseph); H.B. Ward (Herbert B.); R.F. Kelly (Rosemary); E.O. McFalls (Edward)

    2012-01-01

    textabstractAltered expression of mitochondrial electron transport proteins has been shown in early preconditioned myocardial tissue. We wished to determine whether these alterations persist in the Second Window of Protection (SWOP) and if so, whether a favorable energetic state is facilitated

  5. An Analysis of Conjugate Ground-based and Space-based Measurements of Energetic Electrons during Substorms

    Science.gov (United States)

    Sivadas, N.; Semeter, J. L.

    2015-12-01

    Substorms within the Earth's magnetosphere release energy in the form of energetic charged particles and several kinds of waves within the plasma. Depending on their strength, satellite-based navigation and communication systems are adversely affected by the energetic charged particles. Like many other natural phenomena, substorms can have a severe economic impact on a technology-driven society such as ours. Though energization of charged particles is known to occur in the magnetosphere during substorms, the source of this population and its relation to traditional acceleration region dynamics, are not completely understood. Combining measurements of energetic charged particles within the plasmasheet and that of charged particles precipitated in to the ionosphere will provide a better understanding of the role of processes that accelerate these charged particles. In the current work, we present energetic electron flux measured indirectly using data from ground-based Incoherent Scatter Radar and that measured directly at the plasmasheet by the THEMIS spacecraft. Instances of low-altitude-precipitation observed from ground suggest electrons of energy greater than 300 keV, possibly arising from particle injection events during substorms at the magnetically conjugate locations in the plasmasheet. The differences and similarities in the measurements at the plasmasheet and the ionosphere indicate the role different processes play in influencing the journey of these energetic particles form the magnetosphere to the ionosphere. Our observations suggest that there is a lot more to be understood of the link between magnetotail dynamics and energetic electron precipitation during substorms. Understanding this may open up novel and potentially invaluable ways of diagnosing the magnetosphere from the ground.

  6. Energetic electron precipitation and VLF phase disturbances at middle latitudes following the magnetic storm of December 6, 1971

    International Nuclear Information System (INIS)

    Larsen, T.R.; Potemra, T.A.; Imhof, W.L.; Reagan, J.B.

    1977-01-01

    Enhanced fluxes of electrons precipitating over middle latitudes (L approx. 3--4) were detected by the polar-orbiting satellite 1971-089A following a period of magnetic activity starting on December 16, 1971. The electron fluxes measured in 256 differential channels between 130 and 2800 keV have been coordinated with phase observations of VLF radio waves propagating in the earth-ionosphere waveguide. The VLF paths in question, NLK (near Seattle, Washington) and GBR (at Rugby, England) to APL (near Washington, D. C.), cover approx. =120 0 in longitude and range from L approx. 2.5 to L approx. 4.0 in invariant latitude. These paths showed marked daytime and nighttime phase advances from 1650 UT on December 17 (in excess of 10 μs during maximum disturbance). The phase values did not return to prestorm levels before December 22--23. The unusual presence of these daytime VLF disturbances is offered as evidence for the widespread precipitation at low L shell vales of nearly relativistic electrons (E/sub e/> approx.200 keV) which would be required to penetrate below approx.70-km altitude to affect the daytime VLF transmissions. Wave guide mode calculations using D region electron density profiles deduced from the satellite particle data predict phase advances which agree reasonably well with the observed values. It is concluded that the observed long-lived VLF phase disturbances can be explained by excess D region ionization caused by energetic electrons precipitating from the earth's radiation belt following their injection deep into the magnetosphere during the magnetic storm

  7. MULTI-SPACECRAFT OBSERVATIONS AND TRANSPORT MODELING OF ENERGETIC ELECTRONS FOR A SERIES OF SOLAR PARTICLE EVENTS IN AUGUST 2010

    Energy Technology Data Exchange (ETDEWEB)

    Dröge, W.; Kartavykh, Y. Y. [Institut für Theoretische Physik und Astrophysik, Universität Würzburg, D-97074 Würzburg (Germany); Dresing, N.; Klassen, A. [Institut für Experimentelle und Angewandte Physik, Universität Kiel, D-24118 Kiel (Germany)

    2016-08-01

    During 2010 August a series of solar particle events was observed by the two STEREO spacecraft as well as near-Earth spacecraft. The events, occurring on August 7, 14, and 18, originated from active regions 11093 and 11099. We combine in situ and remote-sensing observations with predictions from our model of three-dimensional anisotropic particle propagation in order to investigate the physical processes that caused the large angular spreads of energetic electrons during these events. In particular, we address the effects of the lateral transport of the electrons in the solar corona that is due to diffusion perpendicular to the average magnetic field in the interplanetary medium. We also study the influence of two coronal mass ejections and associated shock waves on the electron propagation, and a possible time variation of the transport conditions during the above period. For the August 18 event we also utilize electron observations from the MESSENGER spacecraft at a distance of 0.31 au from the Sun for an attempt to separate between radial and longitudinal dependencies in the transport process. Our modelings show that the parallel and perpendicular diffusion mean free paths of electrons can vary significantly not only as a function of the radial distance, but also of the heliospheric longitude. Normalized to a distance of 1 au, we derive values of λ {sub ∥} in the range of 0.15–0.6 au, and values of λ {sub ⊥} in the range of 0.005–0.01 au. We discuss how our results relate to various theoretical models for perpendicular diffusion, and whether there might be a functional relationship between the perpendicular and the parallel mean free path.

  8. X-ray spectroscopic technique for energetic electron transport studies in short-pulse laser/plasma interactions

    Energy Technology Data Exchange (ETDEWEB)

    Tutt, T.E.

    1994-12-01

    When a solid target is irradiated by a laser beam, the material is locally heated to a high temperature and a plasma forms. The interaction of the laser with plasma can produce energetic electrons. By observing the behavior of these {open_quotes}hot{close_quotes} electrons, we hope to obtain a better understanding of Laser/Plasma Interactions. In this work we employ a layered-fluorescer technique to study the transport, and therefore the energetics, of the electrons. The plasma forms on a thin foil of metallic Pd which is bonded to thin layer of metallic Sn. Electrons formed from the plasma penetrate first the Pd and then the Sn. In both layers the energetic electrons promote inner (K) shell ionization of the metallic atoms which leads to the emission of characteristic K{sub {alpha}} x-rays of the fluorescers. By recording the x-ray spectrum emitted by the two foils, we can estimate the energy-dependent range of the electrons and their numbers.

  9. Energetic ions and electrons and their acceleration processes in the magnetotail

    International Nuclear Information System (INIS)

    Scholer, M.

    1984-01-01

    Observations of energetic particle fluxes in the geomagnetic tail show that these particles exhibit a bursty appearance on all time scales. Often, however, the bursty appearance is merely due to multiple entries and exits of the spacecraft into and out of the plasma sheet which always contains varying fluxes of energetic particles. Observations of the suprathermal and high-energy component of the plasma sheet are discussed, and observations are presented of energetic particle bursts in the plasma sheet proper, which may be due to a locally ongoing acceleration process. Also discussed are energetic particle phenomena occurring near the edge of the plasma sheet, either during thinning or during recovery. Some recent results from the ISEE 3 deep tail mission bearing on energetic particle acceleration are presented, and the present status of the theory of particle acceleration within the magnetotail is briefly reviewed. 40 references

  10. The Effects of Solar Wind Dynamic Pressure Changes on the Substorm Auroras and Energetic Electron Injections on 24 August 2005

    Science.gov (United States)

    Li, L. Y.; Wang, Z. Q.

    2018-01-01

    After the passage of an interplanetary (IP) shock at 06:13 UT on 24 August 2005, the enhancement (>6 nPa) of solar wind dynamic pressure and the southward turning of interplanetary magnetic field (IMF) cause the earthward movement of dayside magnetopause and the drift loss of energetic particles near geosynchronous orbit. The persistent electron drift loss makes the geosynchronous satellites cannot observe the substorm electron injection phenomenon during the two substorm expansion phases (06:57-07:39 UT) on that day. Behind the IP shock, the fluctuations ( 0.5-3 nPa) of solar wind dynamic pressure not only alter the dayside auroral brightness but also cause the entire auroral oval to swing in the day-night direction. However, there is no Pi2 pulsation in the nightside auroral oval during the substorm growth phase from 06:13 to 06:57 UT. During the subsequent two substorm expansion phases, the substorm expansion activities cause the nightside aurora oval brightening from substorm onset site to higher latitudes, and meanwhile, the enhancement (decline) of solar wind dynamic pressure makes the nightside auroral oval move toward the magnetic equator (the magnetic pole). These observations demonstrate that solar wind dynamic pressure changes and substorm expansion activities can jointly control the luminosity and location of the nightside auroral oval when the internal and external disturbances occur simultaneously. During the impact of a strong IP shock, the earthward movement of dayside magnetopause probably causes the disappearance of the substorm electron injections near geosynchronous orbit.

  11. The Magnetic Local Time Distribution of Energetic Electrons in the Radiation Belt Region

    Science.gov (United States)

    Allison, H. J.

    2017-12-01

    Using fourteen years of electron flux data from the National Oceanic and Atmospheric Administration Polar Operational Environmental Satellites (POES), a statistical study of the magnetic local time (MLT) distribution of the electron population is performed across a range of activity levels, defined by AE, AE*, Kp, solar wind velocity (Vsw), and VswBz. Three electron energies (>30, >100, and >300 keV) are considered. Dawn-dusk flux asymmetries larger than order of magnitude were observed for >30 and >100 keV electrons. For >300 keV electrons, dawn-dusk asymmetries were primarily due to a decrease in the average dusk-side flux beyond L* ˜ 4.5 that arose with increasing activity. For the >30 keV population, substorm injections enhance the dawn-side flux, which may not reach the dusk-side as the electrons can be on open drift paths and lost to the magnetopause. The asymmetries in the >300 keV population are attributed to the combination of magnetopause shadowing and >300 keV electron injections by large electric fields. We suggest that 3D radiation belt models could set the minimum energy boundary (Emin) to 30 keV or above at L* ˜6 during periods of low activity. However, for more moderate conditions, Emin should be larger than 100 keV and, for very extreme activities, ˜300 keV. Our observations show the extent that in-situ electron flux readings may vary during active periods due to the MLT of the satellite and highlight the importance of 4D radiation belt models to fully understand radiation belt processes.

  12. The energetic conditions determining the active dissolution of carbon steel during electrocoagulation in sulfate media

    International Nuclear Information System (INIS)

    Gerónimo-López, Carlos; Vazquez-Arenas, Jorge; Picquart, Michel; González, Ignacio

    2014-01-01

    This study aims to investigate the active dissolution of carbon steel under rotating conditions, necessary for continuous dosing of metal cation in electrocoagulation. A reaction mechanism is proposed for its dissolution in 0.1, 0.3 and 0.5 M Na 2 SO 4 , using electrochemical and chemical techniques (Raman, SEM). A continuous dissolution region was obtained from the potentiodynamic study, as a result of the competition between the rate of electrochemical reactions and the rate at which energetic conditions are imposed on the electrode. On the other hand, the dissolution of carbon steel underwent active, transition and passivation regions in potentiostatic and galvanostatic techniques, which respectively shifted to higher current densities and more positive potentials as the electrolyte concentration (Na 2 SO 4 ) was increased. In general, the increase of Na 2 SO 4 concentration promotes the iron dissolution and tightens the active region. The results revealed that the Na 2 SO 4 concentration, the Fe(II)/Fe(III) interface concentration, and the time of perturbation influence the occurrence and evolution of the Green Rust Sulphate (NaFe 6 II Fe 3 III (OH) 18 (SO 4 ) 2 ) intermediary, a precursor which hinders electrocoagulation through passive film formation. Scanning Electronic Microscopy and Raman spectroscopy showed that in the active dissolution region, the films grown potentiostatically are porous and contain α-FeOOH, δ-FeOOH, and Fe 3 O 4 as the dominant species. In the transition region, these films become less porous and include α-FeOOH, Fe 3 O 4 , α-Fe 2 O 3 , γ-Fe 2 O 3 , while γ-FeOOH was identified in the passive region

  13. Magneto-Hydrodynamic Activity and Energetic Particles - Application to Beta Alfven Eigenmodes

    International Nuclear Information System (INIS)

    Nguyen, Ch.

    2009-12-01

    The goal of magnetic fusion research is to extract the power released by fusion reactions and carried by the product of these reactions, liberated at energies of the order of a few MeV. The feasibility of fusion energy production relies on our ability to confine these energetic particles, while keeping the thermonuclear plasma in safe operating conditions. For that purpose, it is necessary to understand and find ways to control the interaction between energetic particles and the thermonuclear plasma. Reaching these two goals is the general motivation for this work. More specifically, our focus is on one type of instability, the Beta Alfven Eigenmode (BAE), which can be driven by energetic particles and impact on the confinement of both energetic and thermal particles. In this work, we study the characteristics of BAEs analytically and derive its dispersion relation and structure. Next, we analyze the linear stability of the mode in the presence of energetic particles. First, a purely linear description is used, which makes possible to get an analytical linear criterion for BAE destabilization in the presence of energetic particles. This criterion is compared with experiments conducted in the Tore-Supra tokamak. Secondly, because the linear analysis reveals some features of the BAE stability which are subject to a strong nonlinear modification, the question is raised of the possibility of a sub-critical activity of the mode. We propose a simple scenario which makes possible the existence of meta-stable modes, verified analytically and numerically. Such a scenario is found to be relevant to the physics and scales characterizing BAEs. (author)

  14. GLUT4 Mobilization Supports Energetic Demands of Active Synapses.

    Science.gov (United States)

    Ashrafi, Ghazaleh; Wu, Zhuhao; Farrell, Ryan J; Ryan, Timothy A

    2017-02-08

    The brain is highly sensitive to proper fuel availability as evidenced by the rapid decline in neuronal function during ischemic attacks and acute severe hypoglycemia. We previously showed that sustained presynaptic function requires activity-driven glycolysis. Here, we provide strong evidence that during action potential (AP) firing, nerve terminals rely on the glucose transporter GLUT4 as a glycolytic regulatory system to meet the activity-driven increase in energy demands. Activity at synapses triggers insertion of GLUT4 into the axonal plasma membrane driven by activation of the metabolic sensor AMP kinase. Furthermore, we show that genetic ablation of GLUT4 leads to an arrest of synaptic vesicle recycling during sustained AP firing, similar to what is observed during acute glucose deprivation. The reliance on this biochemical regulatory system for "exercising" synapses is reminiscent of that occurring in exercising muscle to sustain cellular function and identifies nerve terminals as critical sites of proper metabolic control. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. Refined energetic ordering for sulphate-water (n = 3-6) clusters using high-level electronic structure calculations

    Science.gov (United States)

    Lambrecht, Daniel S.; McCaslin, Laura; Xantheas, Sotiris S.; Epifanovsky, Evgeny; Head-Gordon, Martin

    2012-10-01

    This work reports refinements of the energetic ordering of the known low-energy structures of sulphate-water clusters ? (n = 3-6) using high-level electronic structure methods. Coupled cluster singles and doubles with perturbative triples (CCSD(T)) is used in combination with an estimate of basis set effects up to the complete basis set limit using second-order Møller-Plesset theory. Harmonic zero-point energy (ZPE), included at the B3LYP/6-311 + + G(3df,3pd) level, was found to have a significant effect on the energetic ordering. In fact, we show that the energetic ordering is a result of a delicate balance between the electronic and vibrational energies. Limitations of the ZPE calculations, both due to electronic structure errors, and use of the harmonic approximation, probably constitute the largest remaining errors. Due to the often small energy differences between cluster isomers, and the significant role of ZPE, deuteration can alter the relative energies of low-lying structures, and, when it is applied in conjunction with calculated harmonic ZPEs, even alters the global minimum for n = 5. Experiments on deuterated clusters, as well as more sophisticated vibrational calculations, may therefore be quite interesting.

  16. The Role of Localized Compressional Ultra-low Frequency Waves in Energetic Electron Precipitation

    Science.gov (United States)

    Rae, I. Jonathan; Murphy, Kyle R.; Watt, Clare E. J.; Halford, Alexa J.; Mann, Ian R.; Ozeke, Louis G.; Sibeck, David G.; Clilverd, Mark A.; Rodger, Craig J.; Degeling, Alex W.; Forsyth, Colin; Singer, Howard J.

    2018-03-01

    Typically, ultra-low frequency (ULF) waves have historically been invoked for radial diffusive transport leading to acceleration and loss of outer radiation belt electrons. At higher frequencies, very low frequency waves are generally thought to provide a mechanism for localized acceleration and loss through precipitation into the ionosphere of radiation belt electrons. In this study we present a new mechanism for electron loss through precipitation into the ionosphere due to a direct modulation of the loss cone via localized compressional ULF waves. We present a case study of compressional wave activity in tandem with riometer and balloon-borne electron precipitation across keV-MeV energies to demonstrate that the experimental measurements can be explained by our new enhanced loss cone mechanism. Observational evidence is presented demonstrating that modulation of the equatorial loss cone can occur via localized compressional wave activity, which greatly exceeds the change in pitch angle through conservation of the first and second adiabatic invariants. The precipitation response can be a complex interplay between electron energy, the localization of the waves, the shape of the phase space density profile at low pitch angles, ionospheric decay time scales, and the time dependence of the electron source; we show that two pivotal components not usually considered are localized ULF wave fields and ionospheric decay time scales. We conclude that enhanced precipitation driven by compressional ULF wave modulation of the loss cone is a viable candidate for direct precipitation of radiation belt electrons without any additional requirement for gyroresonant wave-particle interaction. Additional mechanisms would be complementary and additive in providing means to precipitate electrons from the radiation belts during storm times.

  17. The role of localised Ultra-Low Frequency waves in energetic electron precipitation

    Science.gov (United States)

    Rae, J.; Murphy, K. R.; Watt, C.; Mann, I. R.; Ozeke, L.; Halford, A. J.; Sibeck, D. G.; Clilverd, M. A.; Rodger, C. J.; Degeling, A. W.; Singer, H. J.

    2016-12-01

    Electromagnetic waves play pivotal roles in radiation belt dynamics through a variety of different means. Typically, Ultra-Low Frequency (ULF) waves have historically been invoked for radial diffusive transport leading to both acceleration and loss of outer radiation belt electrons. Very-Low Frequency (VLF) and Extremely-Low Frequency (ELF) waves are generally thought to provide a mechanism for localized acceleration and loss through precipitation into the ionosphere. In this study we present a new mechanism for electron loss through precipitation into the ionosphere due to direct modulation of the loss cone via localized compressional ULF waves. Observational evidence is presented demonstrating that modulation of the equatorial loss cone can occur via localized compressional wave activity. We then perform statistical computations of the probability distribution to determine how likely a given magnetic perturbation would produce a given percentage change in the bounce loss-cone (BLC). We discuss the ramifications of the action of coherent, localized compressional ULF waves on drifting electron populations; their precipitation response can be a complex interplay between electron energy, the shape of the phase space density profile at pitch angles close to the loss cone, ionospheric decay timescales, and the time-dependence of the electron source. We present a case study of compressional wave activity in tandem with riometer and balloon-borne electron precipitation across keV-MeV energies to demonstrate that the experimental measurements can be explained by our new enhanced loss cone mechanism. We determine that the two pivotal components not usually considered are localized ULF wave fields and ionospheric decay timescales. We conclude that ULF wave modulation of the loss cone is a viable candidate for direct precipitation of radiation belt electrons without any additional requirement for gyroresonant wave-particle interaction. Additional mechanisms would be

  18. Possibilities of 50 years experience application of design activity of 'Energoprojekt-Warsaw' for nuclear energetics in future

    International Nuclear Information System (INIS)

    Roguska, M.; Grzebula, K.; Patrycy, A.

    2000-01-01

    The 50 year experience in design activity for energetics can be profitable for Polish nuclear energetics in the future. Especially previous works on nuclear power plant localization, design of nuclear technique objects and system of quality assurance certified (ISO 9001-1994) can give the solid base for design of future nuclear power plant in Poland when needed

  19. Energetic materials research and development activities at Sandia National Laboratories supported under DP-10 programs

    Energy Technology Data Exchange (ETDEWEB)

    Ratzel, A.C. III

    1998-09-01

    This report provides summary descriptions of Energetic Materials (EM) Research and Development activities performed at Sandia National Laboratories and funded through the Department of Energy DP-10 Program Office in FY97 and FY98. The work falls under three major focus areas: EM Chemistry, EM Characterization, and EM Phenomenological Model Development. The research supports the Sandia component mission and also Sandia's overall role as safety steward for the DOE Nuclear Weapons Complex.

  20. A population of highly energetic transient events in the centres of active galaxies

    Science.gov (United States)

    Kankare, E.; Kotak, R.; Mattila, S.; Lundqvist, P.; Ward, M. J.; Fraser, M.; Lawrence, A.; Smartt, S. J.; Meikle, W. P. S.; Bruce, A.; Harmanen, J.; Hutton, S. J.; Inserra, C.; Kangas, T.; Pastorello, A.; Reynolds, T.; Romero-Cañizales, C.; Smith, K. W.; Valenti, S.; Chambers, K. C.; Hodapp, K. W.; Huber, M. E.; Kaiser, N.; Kudritzki, R.-P.; Magnier, E. A.; Tonry, J. L.; Wainscoat, R. J.; Waters, C.

    2017-12-01

    Recent all-sky surveys have led to the discovery of new types of transients. These include stars disrupted by the central supermassive black hole, and supernovae that are 10-100 times more energetic than typical ones. However, the nature of even more energetic transients that apparently occur in the innermost regions of their host galaxies is hotly debated1-3. Here we report the discovery of the most energetic of these to date: PS1-10adi, with a total radiated energy of 2.3 × 1052 erg. The slow evolution of its light curve and persistently narrow spectral lines over ˜ 3 yr are inconsistent with known types of recurring black hole variability. The observed properties imply powering by shock interaction between expanding material and large quantities of surrounding dense matter. Plausible sources of this expanding material are a star that has been tidally disrupted by the central black hole, or a supernova. Both could satisfy the energy budget. For the former, we would be forced to invoke a new and hitherto unseen variant of a tidally disrupted star, while a supernova origin relies principally on environmental effects resulting from its nuclear location. Remarkably, we also discover that PS1-10adi is not an isolated case. We therefore surmise that this new population of transients has previously been overlooked due to incorrect association with underlying central black hole activity.

  1. A theoretical study of molecular structure, optical properties and bond activation of energetic compound FOX-7 under intense electric fields

    Science.gov (United States)

    Tao, Zhiqiang; Wang, Xin; Wei, Yuan; Lv, Li; Wu, Deyin; Yang, Mingli

    2017-02-01

    Molecular structure, vibrational and electronic absorption spectra, chemical reactivity of energetic compound FOX-7, one of the most widely used explosives, were studied computationally in presence of an electrostatic field of 0.01-0.05 a.u. The Csbnd N bond, which usually triggers the decomposition of FOX-7, is shortened/elongated under a parallel/antiparallel field. The Csbnd N bond activation energy varies with the external electric field, decreasing remarkably with the field strength in regardless of the field direction. This is attributed to two aspects: the bond weakening by the field parallel to the Csbnd N bond and the stabilization effect on the transition-state structure by the field antiparallel to the bond. The variations in the structure and property of FOX-7 under the electric fields were further analyzed with its distributional polarizability, which is dependent on the charge transfer characteristics through the Csbnd N bond.

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

    Directory of Open Access Journals (Sweden)

    T. Sarris

    2006-10-01

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

  3. ITER Plasma at Electron Cyclotron Frequency Domain: Stimulated Raman Scattering off Gould-Trivelpiece Modes and Generation of Suprathermal Electrons and Energetic Ions

    Science.gov (United States)

    Stefan, V. Alexander

    2011-04-01

    Stimulated Raman scattering in the electron cyclotron frequency range of the X-Mode and O-Mode driver with the ITER plasma leads to the ``tail heating'' via the generation of suprathermal electrons and energetic ions. The scattering off Trivelpiece-Gould (T-G) modes is studied for the gyrotron frequency of 170GHz; X-Mode and O-Mode power of 24 MW CW; on-axis B-field of 10T. The synergy between the two-plasmon decay and Raman scattering is analyzed in reference to the bulk plasma heating. Supported in part by Nikola TESLA Labs, La Jolla, CA

  4. Electronic excitation of Ti atoms sputtered by energetic Ar+ and He+ from clean and monolayer oxygen covered surfaces

    International Nuclear Information System (INIS)

    Pellin, M.J.; Gruen, D.M.; Young, C.E.; Wiggins, M.D.; Argonne National Lab., IL

    1983-01-01

    Electronic excitation of Ti atoms ejected during energetic ion bombardment (Ar + , He + ) of well characterized clean and oxygen covered polycrystalline Ti metal surfaces has been determined. For states with 0 to 2 eV and 3 to 5.5 eV of electronic energy, static mode laser fluorescence spectroscopy (LFS) and static mode spontaneous fluorescence spectroscopy (SFS) were used respectively. These experiments which were carried out in a UHV ( -10 Torr) system equipped with an Auger spectrometer provide measurements of the correlation between oxygen coverage (0 to 3 monolayers) and the excited state distribution of sputtered Ti atoms. The experimentally determined electronic partition function of Ti atoms does not show an exponential dependence on energy (E) above the ground state but rather an E -2 or E -3 power law dependence. (orig.)

  5. On the interactions between energetic electrons and lightning whistler waves observed at high L-shells on Van Allen Probes

    Science.gov (United States)

    Zheng, H.; Holzworth, R. H., II; Brundell, J. B.; Hospodarsky, G. B.; Jacobson, A. R.; Fennell, J. F.; Li, J.

    2017-12-01

    Lightning produces strong broadband radio waves, called "sferics", which propagate in the Earth-ionosphere waveguide and are detected thousands of kilometers away from their source. Global real-time detection of lightning strokes including their time, location and energy, is conducted with the World Wide Lightning Location Network (WWLLN). In the ionosphere, these sferics couple into very low frequency (VLF) whistler waves which propagate obliquely to the Earth's magnetic field. A good match has previously been shown between WWLLN sferics and Van Allen Probes lightning whistler waves. It is well known that lightning whistler waves can modify the distribution of energetic electrons in the Van Allen belts by pitch angle scattering into the loss cone, especially at low L-Shells (referred to as LEP - Lightning-induced Electron Precipitation). It is an open question whether lightning whistler waves play an important role at high L-shells. The possible interactions between energetic electrons and lightning whistler waves at high L-shells are considered to be weak in the past. However, lightning is copious, and weak pitch angle scattering into the drift or bounce loss cone would have a significant influence on the radiation belt populations. In this work, we will analyze the continuous burst mode EMFISIS data from September 2012 to 2016, to find out lightning whistler waves above L = 3. Based on that, MAGEIS data are used to study the related possible wave-particle interactions. In this talk, both case study and statistical analysis results will be presented.

  6. Initial mechanisms for the decomposition of electronically excited energetic materials: 1,5′-BT, 5,5′-BT, and AzTT

    International Nuclear Information System (INIS)

    Yuan, Bing; Yu, Zijun; Bernstein, Elliot R.

    2015-01-01

    Decomposition of nitrogen-rich energetic materials 1,5′-BT, 5,5′-BT, and AzTT (1,5′-Bistetrazole, 5,5′-Bistetrazole, and 5-(5-azido-(1 or 4)H-1,2,4-triazol-3-yl)tetrazole, respectively), following electronic state excitation, is investigated both experimentally and theoretically. The N 2 molecule is observed as an initial decomposition product from the three materials, subsequent to UV excitation, with a cold rotational temperature (<30 K). Initial decomposition mechanisms for these three electronically excited materials are explored at the complete active space self-consistent field (CASSCF) level. Potential energy surface calculations at the CASSCF(12,8)/6-31G(d) level illustrate that conical intersections play an essential role in the decomposition mechanism. Electronically excited S 1 molecules can non-adiabatically relax to their ground electronic states through (S 1 /S 0 ) CI conical intersections. 1,5′-BT and 5,5′-BT materials have several (S 1 /S 0 ) CI conical intersections between S 1 and S 0 states, related to different tetrazole ring opening positions, all of which lead to N 2 product formation. The N 2 product for AzTT is formed primarily by N–N bond rupture of the –N 3 group. The observed rotational energy distributions for the N 2 products are consistent with the final structures of the respective transition states for each molecule on its S 0 potential energy surface. The theoretically derived vibrational temperature of the N 2 product is high, which is similar to that found for energetic salts and molecules studied previously

  7. First Observations of a Foreshock Bubble at Earth: Implications for Magnetospheric Activity and Energetic Particle Acceleration

    Science.gov (United States)

    Turner, D. L.; Omidi, N.; Sibeck, D. G.; Angelopoulos, V.

    2011-01-01

    Earth?s foreshock, which is the quasi-parallel region upstream of the bow shock, is a unique plasma region capable of generating several kinds of large-scale phenomena, each of which can impact the magnetosphere resulting in global effects. Interestingly, such phenomena have also been observed at planetary foreshocks throughout our solar system. Recently, a new type of foreshock phenomena has been predicted: foreshock bubbles, which are large-scale disruptions of both the foreshock and incident solar wind plasmas that can result in global magnetospheric disturbances. Here we present unprecedented, multi-point observations of foreshock bubbles at Earth using a combination of spacecraft and ground observations primarily from the Time History of Events and Macroscale Interactions during Substorms (THEMIS) mission, and we include detailed analysis of the events? global effects on the magnetosphere and the energetic ions and electrons accelerated by them, potentially by a combination of first and second order Fermi and shock drift acceleration processes. This new phenomena should play a role in energetic particle acceleration at collisionless, quasi-parallel shocks throughout the Universe.

  8. Energetic cost of active branchial ventilation in the sharksucker, Echeneis naucrates

    DEFF Research Database (Denmark)

    Steffensen, J F; Lomholt, J P

    1983-01-01

    active to ram gill ventilation were from 10-50 cm s-1, depending on the size of the fish. 3. Oxygen consumption increased between 3.7 and 5.7% when the fish shifted from ram gill ventilation to active branchial pumping. 4. When water velocity was increased beyond the threshold for ram gill ventilation......1. Sharksuckers use active branchial ventilation when swimming or at rest in stationary water. When attached to a moving object or when placed in a water current, they shift to ram gill ventilation as water velocity exceeds a certain threshold. 2. Water velocities required for the transition from......, no further increase in oxygen consumption was observed. 5. It is concluded that the energetic cost of active ventilation in sharksuckers is lower than has previously been reported for fish in general....

  9. Energetic Assessment of the Nonexercise Activities under Free-Living Conditions

    Directory of Open Access Journals (Sweden)

    Shijie Sun

    2016-01-01

    Full Text Available Nonexercise activities (NAs are common types of physical activity in daily life and critical component in energy expenditure. However, energetic assessment of NA, particularly in free-living subjects, is a technical challenge. In this study, mechanical modeling and portable device were used to evaluate five common types of NA in daily life: sit to stand, lie to sit, bowing while standing, squat, and right leg over left. A human indirect calorimeter was used to measure the activity energy expenditure of NA. Mechanical work and mechanical efficiency of NA were calculated for mechanical modeling. Thirty-two male subjects were recruited for the study (20 subjects for the development of models and 12 subjects for evaluation of models. The average (mean ± SD mechanical work of 5 NAs was 2.31 ± 0.50, 2.88 ± 0.57, 1.75 ± 0.55, 3.96 ± 1.25, and 1.25 ± 0.51 J/kg·m, respectively. The mean mechanical efficiencies of those activities were 22.0 ± 3.3%, 26.5 ± 5.1%, 19.8 ± 3.7%, 24.0 ± 5.5%, and 26.3 ± 5.5%. The activity energy expenditure estimated by the models was not significantly different from the measurements by the calorimeter (p>0.05 with accuracies of 102.2 ± 20.7%, 103.7 ± 25.8%, 105.6 ± 14.6%, 101.1 ± 28.0%, and 95.8 ± 20.7%, respectively, for those activities. These findings suggest that the mechanical models combined with a portable device can provide an alternative method for the energetic analysis of nonexercise activities under free-living condition.

  10. Energetic Assessment of the Nonexercise Activities under Free-Living Conditions.

    Science.gov (United States)

    Sun, Shijie; Tang, Qiang; Quan, Haiying; Lu, Qi; Sun, Ming; Zhang, Kuan

    2016-01-01

    Nonexercise activities (NAs) are common types of physical activity in daily life and critical component in energy expenditure. However, energetic assessment of NA, particularly in free-living subjects, is a technical challenge. In this study, mechanical modeling and portable device were used to evaluate five common types of NA in daily life: sit to stand, lie to sit, bowing while standing, squat, and right leg over left. A human indirect calorimeter was used to measure the activity energy expenditure of NA. Mechanical work and mechanical efficiency of NA were calculated for mechanical modeling. Thirty-two male subjects were recruited for the study (20 subjects for the development of models and 12 subjects for evaluation of models). The average (mean ± SD) mechanical work of 5 NAs was 2.31 ± 0.50, 2.88 ± 0.57, 1.75 ± 0.55, 3.96 ± 1.25, and 1.25 ± 0.51 J/kg·m, respectively. The mean mechanical efficiencies of those activities were 22.0 ± 3.3%, 26.5 ± 5.1%, 19.8 ± 3.7%, 24.0 ± 5.5%, and 26.3 ± 5.5%. The activity energy expenditure estimated by the models was not significantly different from the measurements by the calorimeter (p > 0.05) with accuracies of 102.2 ± 20.7%, 103.7 ± 25.8%, 105.6 ± 14.6%, 101.1 ± 28.0%, and 95.8 ± 20.7%, respectively, for those activities. These findings suggest that the mechanical models combined with a portable device can provide an alternative method for the energetic analysis of nonexercise activities under free-living condition.

  11. Auroral energy input from energetic electrons and Joule heating at Chatanika

    International Nuclear Information System (INIS)

    Wickwar, V.B.; Baron, M.J.; Sears, R.D.

    1975-01-01

    With the incoherent scatter radar at Chatanika, Alaska, a wide variety of measurements can be made related to the ionosphere, magnetosphere, and neutral atmosphere. A significant parameter is the amount of energy transferred from the magnetosphere into the ionosphere and neutral atmosphere during periods of auroral activity. In this report a procedure is examined whereby the incident energy flux of auroral electrons is ascertained from radar measurements. As part of the process radar-determined fluxes are compared with those ascertained from simultaneous photometric observations at 4278 A. The fluxes obtained by both techniques had similar magnitudes and time variations. If it is assumed that the largest uncertainty in the radar/photometer comparison is the effective recombination coefficient, then that coefficient can also be deduced. A value 3times10 -7 cm 3 /s at about 105 km is found, which is in good agreement with other recent determinations during active auroral conditions. This technique is combined with one to ascertain the Joule heating to determine the energy input from the magnetosphere to the ionosphere in a region localized above the radar on March 22, 1973, in the midnight sector. The energy input is continuous at a significant level, i.e., greater than the 3 ergs/cm 2 that could be delivered by the sun, were it overhead. Moreover, at times, each of these inputs became as great as 30 ergs/cm 2 s

  12. Rocket measurements of X-rays and energetic electrons through an auroral arc

    International Nuclear Information System (INIS)

    Aarsnes, K.; Stadsnes, J.; Soeraas, F.

    1976-01-01

    Preliminary results from rocket measurements on auroral electron precipitation are discussed as far as the spatial structure and time and space variations in the primary electron fluxes are concerned. The analysis demonstrates that there was a good overall correspondence between the X-ray and electron data. By using a well collimated X-ray detector on a spinning rocket, it was possible to get additional information on the overall electron precipitation pattern

  13. Energetic Systems

    Data.gov (United States)

    Federal Laboratory Consortium — The Energetic Systems Division provides full-spectrum energetic engineering services (project management, design, analysis, production support, in-service support,...

  14. Plasma and energetic electron flux variations in the Mercury 1 C event: Evidence for a magnetospheric boundary layer

    International Nuclear Information System (INIS)

    Christon, S.P.

    1989-01-01

    Near the outbound magnetopause crossing during the first encounter of Mariner 10 with the planet Mercury on March 29, 1974, large intensity, ∼ 6 s quasi-periodic variations in the intensity-time profile of the charged particle experiment's electron counting rate appeared as a series of peaks and valleys. The peaks have previously been interpreted as quasi-periodic burst sequences of mildly relativistic electrons, caused in one case by episodic ∼ 6-s magnetotail substorm reconnection events and in another case by multiple encounters with a substorm energized electron population drifting around Mercury with an ∼ 6 s drift period. In this paper, the authors offer a new and fundamentally different interpretation of the Mariner 10 energetic electron, plasma electron, and magnetic field data near the outbound magnetopause at Mercury 1. They show that magnetosheath-like boundary layer plasma was observed up to ∼ 360 km planetward of the dawn magnetopause crossing as sensed by the magnetometer. They show that observations of substorm enhanced > 35 keV electron flux (that previously interpreted as > 175 keV electrons) associated with the hot tenuous plasma sheet population were interleaved with ∼ 6 s period observations of a cold dense boundary layer plasma associated with a much lower > 35 keV electron flux. They argue that the ∼ 6 s temporal signature is due to variation of the thickness and/or position of the boundary layer plasma population. This explanation of the ∼ 6-s variations, based upon the analysis of the coincident responses of the magnetic field experiment and two independent charged particle instruments (at their highest temporal resolutions), finds a direct analogue in observations of Earth's magnetospheric boundary layer, although the time scales are significantly shorter at Mercury

  15. Resonant scattering of energetic electrons in the plasmasphere by monotonic whistler-mode waves artificially generated by ionospheric modification

    Directory of Open Access Journals (Sweden)

    S. S. Chang

    2014-05-01

    Full Text Available Modulated high-frequency (HF heating of the ionosphere provides a feasible means of artificially generating extremely low-frequency (ELF/very low-frequency (VLF whistler waves, which can leak into the inner magnetosphere and contribute to resonant interactions with high-energy electrons in the plasmasphere. By ray tracing the magnetospheric propagation of ELF/VLF emissions artificially generated at low-invariant latitudes, we evaluate the relativistic electron resonant energies along the ray paths and show that propagating artificial ELF/VLF waves can resonate with electrons from ~ 100 keV to ~ 10 MeV. We further implement test particle simulations to investigate the effects of resonant scattering of energetic electrons due to triggered monotonic/single-frequency ELF/VLF waves. The results indicate that within the period of a resonance timescale, changes in electron pitch angle and kinetic energy are stochastic, and the overall effect is cumulative, that is, the changes averaged over all test electrons increase monotonically with time. The localized rates of wave-induced pitch-angle scattering and momentum diffusion in the plasmasphere are analyzed in detail for artificially generated ELF/VLF whistlers with an observable in situ amplitude of ~ 10 pT. While the local momentum diffusion of relativistic electrons is small, with a rate of −7 s−1, the local pitch-angle scattering can be intense near the loss cone with a rate of ~ 10−4 s−1. Our investigation further supports the feasibility of artificial triggering of ELF/VLF whistler waves for removal of high-energy electrons at lower L shells within the plasmasphere. Moreover, our test particle simulation results show quantitatively good agreement with quasi-linear diffusion coefficients, confirming the applicability of both methods to evaluate the resonant diffusion effect of artificial generated ELF/VLF whistlers.

  16. Transport of energetic electrons in a magnetically expanding helicon double layer plasma

    International Nuclear Information System (INIS)

    Takahashi, Kazunori; Charles, Christine; Boswell, Rod; Cox, Wes; Hatakeyama, Rikizo

    2009-01-01

    Peripheral magnetic field lines extending from the plasma source into the diffusion chamber are found to separate two regions of Maxwellian electron energy probability functions: the central, ion-beam containing region with an electron temperature of 5 eV, and region near the chamber walls with electrons at 3 eV. Along the peripheral field lines a bi-Maxwellian population with a hot tail at 9 eV is shown to both originate from electrons in the source traveling downstream across the double layer and correspond to a local maximum in ion and electron densities.

  17. On the morphology of energetic (>= 30 keV) electron precipitation at the onset of negative magnetic bays

    International Nuclear Information System (INIS)

    Pytte, T.; Trefall, H.; Kremser, G.; Tanskanen, P.; Riedler, W.

    1976-01-01

    Recordings of Bremsstrahlung X-rays supported by recordings of cosmic noise absorption have been used to study in detail energetic (>= 30 keV) electron precipitation events occurring near local midnight at the onset of the expansion phase of magnetospheric substorms. This type of precipitation occurs during the first 5 to 10 min after bay onset and can usually be distinguished from the subsequent bay-associated precipitation by its characteristic time structure, variation in energy spectrum, and higher intensities. During this same interval, the poleward border of the precipitation region moves rapidly towards higher latitudes with speeds of typically 1 to 2 km/s, whereas the equatorward border seems to move slowly towards lower latitudes. The northward expansion starts just poleward of the lowest latitudes reached during the slow equatorward motion of the preceding growth-phase precipitation. The previous narrow precipitation region may thus expand to as much as 10 0 of invariant latitude within a few minutes. Within the expanding region there are additional intrinsic temporal variations. As the flux of precipitating electrons tends to be most intense and most energetic near the poleward border, recordings made northward of the latitude where the poleward motion started tend to give the appearance of an impulsive precipiation event. The bay-onset precipiation starts abruptly at the onset of Pi 2 magnetic pulsations. Associated with these pulsations there are modulations of the flux of precipitating electrons. An intensified westward electrojet appears to have its center in the equatorward part of the precipitation region. The results are discussed and a mechanism is proposed. (author)

  18. The influence of preformed plasma on the surface-guided lateral transport of energetic electrons in ultraintense short laser–foil interactions

    International Nuclear Information System (INIS)

    Yuan, X H; Zheng, J; Liu, J L; Fang, Y; Sheng, Z M; Carroll, D C; Gray, R J; Brenner, C M; Coury, M; Tresca, O; Neely, D; McKenna, P; Chen, L M; Li, Y T; Zielbauer, B; Kühl, T

    2014-01-01

    The lateral transport patterns of energetic electrons in thin foil targets irradiated with relativistically intense, picosecond laser pulses with different peak-to-pedestal intensity contrast ratios are reported. For ‘low contrast’ pulses, a large current of energetic electrons is found to be transported along the target front surface, due to the formation of strong quasi-static electric and magnetic fields. This is distinctly different from the case with ‘high contrast’ pulses, where energetic electrons are spatially confined. Although this lateral transport reduces the efficiency of the laser energy coupling into ion and radiation production in the region of the laser focus, it can play an important role in directing energy transport in advanced fast ignition schemes involving hollow cone targets and also in heating the target (to generate states of warm dense matter) in regions far from the drive laser focus. (paper)

  19. Comparison between POES energetic electron precipitation observations and riometer absorptions: Implications for determining true precipitation fluxes

    Science.gov (United States)

    Rodger, Craig J.; Kavanagh, Andrew J.; Clilverd, Mark A.; Marple, Steve R.

    2013-12-01

    electron precipitation (EEP) impacts the chemistry of the middle atmosphere with growing evidence of coupling to surface temperatures at high latitudes. To better understand this link, it is essential to have realistic observations to properly characterize precipitation and which can be incorporated into chemistry-climate models. The Polar-orbiting Operational Environmental Satellite (POES) detectors measure precipitating particles but only integral fluxes and only in a fraction of the bounce loss cone. Ground-based riometers respond to precipitation from the whole bounce loss cone; they measure the cosmic radio noise absorption (CNA), a qualitative proxy with scant direct information on the energy flux of EEP. POES observations should have a direct relationship with ΔCNA and comparing the two will clarify their utility in studies of atmospheric change. We determined ionospheric changes produced by the EEP measured by the POES spacecraft in ~250 overpasses of an imaging riometer in northern Finland. The ΔCNA modeled from the POES data is 10-15 times less than the observed ΔCNA when the >30 keV flux is reported as ground-based measurements. The discrepancy occurs mostly during periods of low geomagnetic activity, and we contend that weak diffusion is dominating the pitch angle scattering into the bounce loss cone at these times. A correction to the calculation using measurements of the trapped flux considerably reduces the discrepancy and provides further support to our hypothesis that weak diffusion leads to underestimates of the EEP.

  20. Time integrated x-ray measurments of the very energetic electron end loss profile in TMX-U

    International Nuclear Information System (INIS)

    Osher, J.E.; Fabyan, J.

    1984-01-01

    The time-integrated 2-D profile of the thick-target bremsstrahlung produced by energetic end loss electrons has been measured during ECRH operation of TMX-U. Sheets of x-ray film and/or arrays of thermoluminescent dosimeters were placed on the outside of the end tank end wall to measure the relative spatial x-ray profile, with locally added filters of Pb to determine the effective mean x-ray energy. The purpose of this simple survey diagnostic was to allow deduction of the gross features of the ECRH region. The electron source functions needed to fit the x-ray data were modeled for various anchor cell radial distributions mapped along magnetic field lines to the elliptical plasma potential control plates or the Al end walls. The data are generally consistent with (1) major ECR heating in the central 25-cm-diam core, (2) a mean ECRH electron loss energy of 420 keV, and (3) an ECRH coupling efficiency to these hot electrons of greater than or equal to 10%

  1. Void formation in pure aluminium irradiated with high-energetic electron beams and gamma-quanta

    DEFF Research Database (Denmark)

    Gan, V. V.; Ozhigou, L. S.; Yamnitsky, V. A.

    1983-01-01

    The spatial distribution of displaced atoms and helium atoms and also the spectra of damaging energies of primary displaced atoms in a thick aluminium target irradiated with electrons of 225 MeV energy were calculated. Pure aluminium (99.9999%) irradiated up to 0.04 dose was studied by electron...

  2. Energetics of bacterial photosynthesis.

    Science.gov (United States)

    Lebard, David N; Matyushov, Dmitry V

    2009-09-10

    We report the results of extensive numerical simulations and theoretical calculations of electronic transitions in the reaction center of Rhodobacter sphaeroides photosynthetic bacterium. The energetics and kinetics of five electronic transitions related to the kinetic scheme of primary charge separation have been analyzed and compared to experimental observations. Nonergodic formulation of the reaction kinetics is required for the calculation of the rates due to a severe breakdown of the system ergodicity on the time scale of primary charge separation, with the consequent inapplicability of the standard canonical prescription to calculate the activation barrier. Common to all reactions studied is a significant excess of the charge-transfer reorganization energy from the width of the energy gap fluctuations over that from the Stokes shift of the transition. This property of the hydrated proteins, breaking the linear response of the thermal bath, allows the reaction center to significantly reduce the reaction free energy of near-activationless electron hops and thus raise the overall energetic efficiency of the biological charge-transfer chain. The increase of the rate of primary charge separation with cooling is explained in terms of the temperature variation of induction solvation, which dominates the average donor-acceptor energy gap for all electronic transitions in the reaction center. It is also suggested that the experimentally observed break in the Arrhenius slope of the primary recombination rate, occurring near the temperature of the dynamical transition in proteins, can be traced back to a significant drop of the solvent reorganization energy close to that temperature.

  3. Chemical kinetics and relaxation of non-equilibrium air plasma generated by energetic photon and electron beams

    International Nuclear Information System (INIS)

    Maulois, Melissa; Ribière, Maxime; Eichwald, Olivier; Yousfi, Mohammed; Azaïs, Bruno

    2016-01-01

    The comprehension of electromagnetic perturbations of electronic devices, due to air plasma-induced electromagnetic field, requires a thorough study on air plasma. In the aim to understand the phenomena at the origin of the formation of non-equilibrium air plasma, we simulate, using a volume average chemical kinetics model (0D model), the time evolution of a non-equilibrium air plasma generated by an energetic X-ray flash. The simulation is undertaken in synthetic air (80% N_2 and 20% O_2) at ambient temperature and atmospheric pressure. When the X-ray flash crosses the gas, non-relativistic Compton electrons (low energy) and a relativistic Compton electron beam (high energy) are simultaneously generated and interact with the gas. The considered chemical kinetics scheme involves 26 influent species (electrons, positive ions, negative ions, and neutral atoms and molecules in their ground or metastable excited states) reacting following 164 selected reactions. The kinetics model describing the plasma chemistry was coupled to the conservation equation of the electron mean energy, in order to calculate at each time step of the non-equilibrium plasma evolution, the coefficients of reactions involving electrons while the energy of the heavy species (positive and negative ions and neutral atoms and molecules) is assumed remaining close to ambient temperature. It has been shown that it is the relativistic Compton electron beam directly created by the X-ray flash which is mainly responsible for the non-equilibrium plasma formation. Indeed, the low energy electrons (i.e., the non-relativistic ones) directly ejected from molecules by Compton collisions contribute to less than 1% on the creation of electrons in the plasma. In our simulation conditions, a non-equilibrium plasma with a low electron mean energy close to 1 eV and a concentration of charged species close to 10"1"3" cm"−"3 is formed a few nanoseconds after the peak of X-ray flash intensity. 200 ns after the

  4. Emission of low-energetic electrons in collisions of heavy ions with solid targets

    International Nuclear Information System (INIS)

    Lineva, Natallia

    2008-07-01

    At the UNILAC accelerator, we have initiated a project with the objective to investigate lowenergy electrons, emitted from solid, electrically conductive targets after the impact of swift light and heavy ions. For this purposes, we have installed, optimized, and put into operation an electrostatic toroidal electron spectrometer. First, investigations of electrons, emitted from solid-state targets after the bombardment with a monochromatic electron beam from an electron gun, has been carried out. The proposed method combines the results of the measurements with the results of dedicated Monte Carlo simulations. The method has been elaborated in a case study for carbon targets. The findings have been instrumental for the interpretation of our measurements of electrons emitted in collisions of swift ions with the same carbon targets. Our investigations focused on following ion beams: protons and (H + 3 )-molecules of the same energy, as well as on carbon ions with two different energies. Thin carbon, nickel, argon and gold foils has been used as targets. Electrons in the energy range between 50 eV and 1 keV have been investigated. The measured electron distributions, both integral as well as differential with respect to the polar angle, have been compared to simple standard theories for gases as well as to the results of TRAX simulations, the latter being based on data from gaseous targets. Dedicated TRAX simulations have been performed only for the carbon targets, applying the method mentioned above. Within our experimental uncertainties, we observe a good agreement of the measured and TRAX simulated data. That leads us to the conclusion that - as a first order approximation - the electron emission pattern from ion-atom collisions in solid-state targets and the one from single collisions in gases are similar. (orig.)

  5. Energetic electron measurements in the edge of a reversed-field pinch

    International Nuclear Information System (INIS)

    Ingraham, J.C.; Ellis, R.F.; Downing, J.N.; Munson, C.P.; Weber, P.G.; Wurden, G.A.

    1990-01-01

    The edge plasma of the ZT-40M [Fusion Technol. 8, 1571 (1985)] reversed-field pinch has been studied using a combination of three different plasma probes: a double-swept Langmuir probe, an electrostatic energy analyzer, and a calorimeter--Langmuir probe. The edge plasma has been measured both with and without a movable graphite tile limiter present nearby in the plasma. Without a limiter a fast nonthermal tail of electrons (T congruent 350 eV) is detected in the edge plasma with nearly unidirectional flow along B and having a density between 2% and 10% of the cold edge plasma (T congruent 20 eV). The toroidal sense of this fast electron flow is against the force of the applied electric field. A large power flux along B is measured flowing in the same direction as the fast electrons and is apparently carried by the fast electrons. With the limiter present the fast electrons are still detected in the plasma, but are strongly attenuated in the shadow of the limiter. The measured scrape-off lengths for both the fast electrons and the cold plasma indicate cross-field transport at the rate of, or less than, Bohm diffusion. Estimates indicate that the fast electrons could carry the reversed-field pinch current density at the edge and, from the measured transverse diffusion rates, could also account for the electron energy loss channel in ZT-40 M. The long mean-free-path kinetic nature of these fast electrons suggests that a kinetic process, rather than a magnetohydrodynamic process that is based upon a local Ohm's law formulation, is responsible for their generation

  6. Calculation of effective atomic number and electron density of essential biomolecules for electron, proton, alpha particle and multi-energetic photon interactions

    Science.gov (United States)

    Kurudirek, Murat; Onaran, Tayfur

    2015-07-01

    Effective atomic numbers (Zeff) and electron densities (Ne) of some essential biomolecules have been calculated for total electron interaction, total proton interaction and total alpha particle interaction using an interpolation method in the energy region 10 keV-1 GeV. Also, the spectrum weighted Zeff for multi-energetic photons has been calculated using Auto-Zeff program. Biomolecules consist of fatty acids, amino acids, carbohydrates and basic nucleotides of DNA and RNA. Variations of Zeff and Ne with kinetic energy of ionizing charged particles and effective photon energies of heterogeneous sources have been studied for the given materials. Significant variations in Zeff and Ne have been observed through the entire energy region for electron, proton and alpha particle interactions. Non-uniform variation has been observed for protons and alpha particles in low and intermediate energy regions, respectively. The maximum values of Zeff have found to be in higher energies for total electron interaction whereas maximum values have found to be in relatively low energies for total proton and total alpha particle interactions. When it comes to the multi-energetic photon sources, it has to be noted that the highest Zeff values were found at low energy region where photoelectric absorption is the pre-dominant interaction process. The lowest values of Zeff have been shown in biomolecules such as stearic acid, leucine, mannitol and thymine, which have highest H content in their groups. Variation in Ne seems to be more or less the same with the variation in Zeff for the given materials as expected.

  7. Effect of Trapped Energetic Ions on MHD Activity in Spherical Tori

    International Nuclear Information System (INIS)

    White, R.B.; Kolesnichenko, Ya.I.; Lutsenko, V.V.; Marchenko, V.S.

    2002-01-01

    It is shown that the increase of beta (the ratio of plasma pressure to the magnetic field pressure) may change the character of the influence of trapped energetic ions on MHD stability in spherical tori. Namely, the energetic ions, which stabilize MHD modes (such as the ideal-kink mode, collisionless tearing mode, and semi-collisional tearing mode) at low beta, have a destabilizing influence at high beta unless the radial distribution of the energetic ions is very peaked

  8. Simulation and modeling of whistler-mode wave growth through cyclotron resonance with energetic electrons in the magnetosphere

    International Nuclear Information System (INIS)

    Carlson, C.R.

    1987-01-01

    New models and simulations of wave growth experienced by electromagnetic waves propagating through the magnetosphere in the whistler mode are presented. For these waves, which have frequencies below the electron gyro and plasma frequencies, the magnetospheric plasma acts like a natural amplifier often amplifying the waves by ∼ 30 dB. The mechanism for growth is cyclotron resonance between the circularly polarized waves and the gyrating energetic electrons which make up the Van Allen radiation belts. The main emphasis is to simulate single-frequency wave pulses, in the 2-6 kHz range, that have been injected into the magnetosphere, near L ∼ 4, by the Stanford transmitting facility at Siple station, Antarctica. However, the results can also be applied to naturally occurring signals, signals from other transmitters, non-CW signals, and signals in other parts of the magnetosphere not probed by the Siple Station transmitter. Results show the importance of the transient aspects in the wave-growth process. The wave growth established as the wave propagates toward the equator, is given a spatially advancing wave phase structure by the geomagnetic inhomogeneity. Through the feedback of this radiation upon other electrons, conditions are set up that results in the linearly increasing output frequency with time

  9. High-resolution energetic particle measurements at 6.6 R/sub E/ 1. Electron micropulsations

    International Nuclear Information System (INIS)

    Higbie, P.R.; Belian, R.D.; Baker, D.N.

    1978-01-01

    The three papers dealing with data from satellites 1976--059A which we present in this issue represent the first publication of data from the new series of charged particle analyzer (CPA) instruments designed to measure energetic particle fluxes at geosynchronous altitudes. This first report presents new results on electron micropulsation phenomena and includes a concise description of the instrument. We often observe highly periodic modulations which persist for times as long as 2 hours in the spin-averaged counting rate data. These flux oscillations occur most frequently in the 30- to 300-keV electron data but are occasionally seen in higher-energy electron or low-energy proton data. The pitch angle distributions of the observed modulated fluxes may be either 'cigar-shaped' or 'pancake-shaped.' Oscillations at different energies are in phase, although the gross counting rate may be changing in an energy-time dispersive manner. The occurrence distribution of these modulations in local time suggests that they are related to Pc 5 geomagnetic micropulsations observed at ground stations

  10. Distribution characteristics of energetic electron according to data of Interkosmos-17 satellite

    International Nuclear Information System (INIS)

    Martynov, A.I.; Makhmutov, V.S.; Petrov, V.M.; Shurshakov, V.A.

    1990-01-01

    Distributions of quasi-captured and precipitating electrons with E=10-70 keV within L=3-15 by local time and local pitch-angle for different conditions of magnetic perturbation are studied using measurement data from Interkosmos-17 satellite (polar circular orbit, h∼500 km). Dependence of electron flows on local time obtained for K p >1 is close to corresponding dependence from AE-4 model, and level of magnetosphere perturbation affects character of this dependence. Electron distributions by invariant latitude in the Earth polar cap are calculated at different levels of geomagnetic perturbation; electron flows during strong magnetic perturbations (K p >4) increase by ∼2 times, in this case, space heterogeneity of their distribution is intensified

  11. Monitoring of energetic characteristics of electron beams during formation of high-power pulsed bremsstrahlung

    International Nuclear Information System (INIS)

    Ivaschenko, D.M.; Mordasov, N.G.; Chlenov, A.M.

    2005-01-01

    A method and a device for monitoring the dynamic and integrated characteristics of high-power electron and bremsstrahlung beams of the pulse accelerators are proposed. The transfer functions for various types of a target in operating conditions of the pulse accelerator UIN-10 are presented. Possibilities if the integrated diagnostics of acceleration rate of the electron beams with simultaneous testing of the bremsstrahlung parameters as a local field point beyond the converting target are shown [ru

  12. THE POSSIBLE ROLE OF CORONAL STREAMERS AS MAGNETICALLY CLOSED STRUCTURES IN SHOCK-INDUCED ENERGETIC ELECTRONS AND METRIC TYPE II RADIO BURSTS

    Energy Technology Data Exchange (ETDEWEB)

    Kong, Xiangliang; Chen, Yao; Feng, Shiwei; Wang, Bing; Du, Guohui [Shandong Provincial Key Laboratory of Optical Astronomy and Solar-Terrestrial Environment, and Institute of Space Sciences, Shandong University, Weihai, Shandong 264209 (China); Guo, Fan [Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Li, Gang, E-mail: yaochen@sdu.edu.cn [Department of Space Science and CSPAR, University of Alabama in Huntsville, Huntsville, AL 35899 (United States)

    2015-01-10

    Two solar type II radio bursts, separated by ∼24 hr in time, are examined together. Both events are associated with coronal mass ejections (CMEs) erupting from the same active region (NOAA 11176) beneath a well-observed helmet streamer. We find that the type II emissions in both events ended once the CME/shock fronts passed the white-light streamer tip, which is presumably the magnetic cusp of the streamer. This leads us to conjecture that the closed magnetic arcades of the streamer may play a role in electron acceleration and type II excitation at coronal shocks. To examine such a conjecture, we conduct a test-particle simulation for electron dynamics within a large-scale partially closed streamer magnetic configuration swept by a coronal shock. We find that the closed field lines play the role of an electron trap via which the electrons are sent back to the shock front multiple times and therefore accelerated to high energies by the shock. Electrons with an initial energy of 300 eV can be accelerated to tens of keV concentrating at the loop apex close to the shock front with a counter-streaming distribution at most locations. These electrons are energetic enough to excite Langmuir waves and radio bursts. Considering the fact that most solar eruptions originate from closed field regions, we suggest that the scenario may be important for the generation of more metric type IIs. This study also provides an explanation of the general ending frequencies of metric type IIs at or above 20-30 MHz and the disconnection issue between metric and interplanetary type IIs.

  13. Measurements of the stability of energetic electron beams in the ionosphere

    International Nuclear Information System (INIS)

    Duprat, G.R.J.; Whalen, B.A.; McNamara, A.G.; Bernstein, W.

    1983-01-01

    A Nike Black Brant V rocket was launched from the Chruchill Research Range (Manitoba) on December 3, 1979, into a bright east-west oriented auroral arc. The rocket payload consisted of two separable sections, each containing its own telemetry and a full set of wave and charged particle detectors. An electron gun, carried in the main payload, produced a pulsed electron beam with energies of 1.9, 4, and 8 keV at 1, 10, and approximately 100 mA in a programmed format. Charged particle observations from the flight are used to define the spatial distribution of perturbed volume surrounding the accelerator during gun firing. The radial dimensions of the perturbation were found to scale with the primary electron beam gyroradius and current and were also dependent on the beam injection angle. On magnetic field lines near the gun, the induced return electron energy spectrum is characterized by a monotonically decreasing intensity with increasing energy out to the approximate beam energy. At increasing distances across field lines the energy spectrum takes on a monoenergetic appearance peaked near the beam energy. All beam-induced electron fluxes frop rapidly to background at the edge of the perturbed volume. The intense flux of low-energy electrons observed on field lines near the rocket are shown to be accelerated ambients, whereas the particles at or near the beam energy and at large radial distances are presumably beam primaries. The ambient thermal ion plasma was not measurably affected by the beam while the local electron temperature increased during gun pulses. Results from this flight are compared with the corresponding observations made in a large vacuum tank simulation, and it is concluded that certain features in the data are consistent with the beam-plasma instability observed in the laboratory

  14. Energetic electron propagation in the decay phase of non-thermal flare emission

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Jing; Yan, Yihua [Key Laboratory of Solar Activities, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China); Tsap, Yuri T., E-mail: huangj@nao.cas.cn [Crimean Astrophysical Observatory of Kyiv National Taras Shevchenko University, 98409 Crimea, Nauchny (Ukraine)

    2014-06-01

    On the basis of the trap-plus-precipitation model, the peculiarities of non-thermal emission in the decay phase of solar flares have been considered. The calculation formulas for the escape rate of trapped electrons into the loss cone in terms of time profiles of hard X-ray (HXR) and microwave (MW) emission have been obtained. It has been found that the evolution of the spectral indices of non-thermal emission depend on the regimes of the pitch angle diffusion of trapped particles into the loss cone. The properties of non-thermal electrons related to the HXR and MW emission of the solar flare on 2004 November 3 are studied with Nobeyama Radioheliograph, Nobeyama Radio Polarimeters, RHESSI, and Geostationary Operational Environmental Satellite observations. The spectral indices of non-thermal electrons related to MW and HXR emission remained constant or decreased, while the MW escape rate as distinguished from that of the HXRs increased. This may be associated with different diffusion regimes of trapped electrons into the loss cone. New arguments in favor of an important role of the superstrong diffusion for high-energy electrons in flare coronal loops have been obtained.

  15. Heating of energetic electrons and ELMO ring formation in symmetric mirror facility

    International Nuclear Information System (INIS)

    Quon, B.H.; Dandl, R.A.; Lazar, N.H.; Wuerker, R.F.

    1982-01-01

    The spatial structure of the high beta, hot-electron ECH plasma, (ELMO Ring), has been studied by using a Hall probe array diagnostic system which measures the diamagnetic field of the hot electron plasma in a large number of spatial locations. The steady state pressure profile obtained using a two-gaussian geometric model that best fits the measurements is found to peak at the mirror midplane near the vacuum field second harmonic resonant point. The radial width of the ring is typically 4 to 7 cm, and the axial length extends significantly beyond the second harmonic resonance zone of the total magnetic field. The radial thickness and the Ring beta are increased by multiple frequency ECH. The electron ring is observed to evolve from a sloshing-like turning point distribution which was observed in the early times following a microwave turnon, demonstrating stochastic processes involved in ELMO Ring formation

  16. Defect production and annihilation in metals through electronic excitation by energetic heavy ion bombardment

    Energy Technology Data Exchange (ETDEWEB)

    Iwase, Akihiro [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1997-03-01

    Defect production, radiation annealing and defect recovery are studied in Ni and Cu irradiated with low-energy ({approx}1-MeV) and high-energy ({approx}100-MeV) ions. Irradiation of Ni with {approx}100-MeV ions causes an anomalous reduction, or even a complete disappearance of the stage-I recovery. This result shows that the energy transferred from excited electrons to lattice atoms through the electron-lattice interaction contributes to the annihilation of the stage-I interstitials. This effect is also observed in Ni as a large radiation annealing during 100-MeV heavy ion irradiation. On the other hand, in Cu thin foils, we find the defect production process strongly associated with electron excitation, where the defect production cross section is nearly proportional to S{sub e}{sup 2}. (author)

  17. Energetic electron processes fluorescence effects for structured nanoparticles X-ray analysis and nuclear medicine applications

    Energy Technology Data Exchange (ETDEWEB)

    Taborda, A.; Desbrée, A. [Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-HOM/SDI/LEDI, BP-17, 31, Avenue de la Division Leclerc, 92262 Fontenay-aux-Roses (France); Carvalho, A. [IEQUALTECS, Lda, Rua Dr. Francisco Sá Carneiro, 36, 2500-065 S. Gregório CLD (Portugal); Chaves, P.C. [C" 2TN, Campus Tecnológico e Nuclear, Instituto Superior Técnico, Universidade de Lisboa, EN10 km 139.7, 2685-066 Bobadela LRS (Portugal); Reis, M.A., E-mail: mareis@ctn.tecnico.ulisboa.pt [IEQUALTECS, Lda, Rua Dr. Francisco Sá Carneiro, 36, 2500-065 S. Gregório CLD (Portugal); C" 2TN, Campus Tecnológico e Nuclear, Instituto Superior Técnico, Universidade de Lisboa, EN10 km 139.7, 2685-066 Bobadela LRS (Portugal)

    2016-08-15

    Superparamagnetic iron oxide (SPIO) nanoparticles are widely used as contrast agents for nuclear magnetic resonance imaging (MRI), and can be modified for improved imaging or to become tissue-specific or even protein-specific. The knowledge of their detailed elemental composition characterisation and potential use in nuclear medicine applications, is, therefore, an important issue. X-ray fluorescence techniques such as particle induced X-ray emission (PIXE) or X-ray fluorescence spectrometry (XRF), can be used for elemental characterisation even in problematic situations where very little sample volume is available. Still, the fluorescence coefficient of Fe is such that, during the decay of the inner-shell ionised atomic structure, keV Auger electrons are produced in excess to X-rays. Since cross-sections for ionisation induced by keV electrons, for low atomic number atoms, are of the order of 10{sup 3} barn, care should be taken to account for possible fluorescence effects caused by Auger electrons, which may lead to the wrong quantification of elements having atomic number lower than the atomic number of Fe. Furthermore, the same electron processes will occur in iron oxide nanoparticles containing {sup 57}Co, which may be used for nuclear medicine therapy purposes. In the present work, simple approximation algorithms are proposed for the quantitative description of radiative and non-radiative processes associated with Auger electrons cascades. The effects on analytical processes and nuclear medicine applications are quantified for the case of iron oxide nanoparticles, by calculating both electron fluorescence emissions and energy deposition on cell tissues where the nanoparticles may be embedded.

  18. The effect of energetic electron precipitation on the nitric oxide density in the lower thermosphere

    International Nuclear Information System (INIS)

    Saetre, Camilla

    2006-12-01

    The objective of this thesis has been the study of the chemical effects of the electron precipitation in the upper atmosphere, and mainly the increase of thermospheric nitric oxide (NO). NO plays an important role in the temperature balance for the mesosphere and thermosphere.In this project auroral electron precipitation data, derived from the Polar Ionospheric X-ray Imaging Experiment (PIXIE) and the Ultraviolet Imager (UVI) on board the Polar satellite, have been used together with NO density measurements from the Student Nitric Oxide Explorer (SNOE)

  19. Effects of antidiuretic hormone on kinetic and energetic determinants of active sodium transport in frog skin.

    Science.gov (United States)

    Lau, Y T; Lang, M A; Essig, A

    1981-10-02

    The effects of antidiuretic hormone (ADH) on the rate of transepithelial active Na transport JaNa and the rate of suprabasal O2 consumption of Jsbr were studied in paired hemiskins of frog. Within some 30 min following administration of ADH both JaNa and Jsbr increased to near-maximal levels and then remained stable for at least an hour. On symmetric perturbation of the transepithelial electrical potential delta psi at 6-min intervals, the dependence of JaNa and Jsbr on delta psi was near-linear, both in control and experimental hemi-skins. The stability and near-linearity of the system permitted systematic analysis of the parameters of linear non-equilibrium thermodynamic (NET) and electrical equivalent circuit (EC) formulations. ADH (100 mU/ml) stimulated two of the three NET phenomenological L coefficients, as well as A, the affinity (negative Gibbs free energy) of a metabolic reaction driving transport. Observations at partially depressed levels of transport indicated that the effects of kinetic and energetic factors are to some extent discrete. EC analysis showed stimulation of the amiloride-sensitive conductance Ka, but not of the apparent electromitive force of Na transport 'ENa'. Similar effects were produced by 10 mU/ml of ADH or by 10 mM dibutyryl cyclic AMP, although less marked effects on the L coefficients were noted with the lower concentration of hormone. It is suggested that, in contrast to EC analysis, the NET formulation distinguishes between kinetic and energetic determinants of transport, supporting a dual mechanism of action of ADH.

  20. Time dependent degradation of energetic electrons in gaseous and condensed media

    International Nuclear Information System (INIS)

    Dillon, M.; Kimura, M.

    1987-01-01

    A transport equation formulated by Spencer and Fano has been used to calculate initial yields of products formed by electron interactions under conditions of steady state irradiation. Since experimental observation of initial yields may now be possible it is desirable to generalize the treatment of Spencer and Fano to include transient effects explicitly. 6 refs., 2 figs

  1. Analysis of trends between solar wind velocity and energetic electron fluxes at geostationary orbit using the reverse arrangement test

    Science.gov (United States)

    Aryan, Homayon; Boynton, Richard J.; Walker, Simon N.

    2013-02-01

    A correlation between solar wind velocity (VSW) and energetic electron fluxes (EEF) at the geosynchronous orbit was first identified more than 30 years ago. However, recent studies have shown that the relation between VSW and EEF is considerably more complex than was previously suggested. The application of process identification technique to the evolution of electron fluxes in the range 1.8 - 3.5 MeV has also revealed peculiarities in the relation between VSW and EEF at the geosynchronous orbit. It has been revealed that for a constant solar wind density, EEF increase with VSW until a saturation velocity is reached. Beyond the saturation velocity, an increase in VSW is statistically not accompanied with EEF enhancement. The present study is devoted to the investigation of saturation velocity and its dependency upon solar wind density using the reverse arrangement test. In general, the results indicate that saturation velocity increases as solar wind density decreases. This implies that solar wind density plays an important role in defining the relationship between VSW and EEF at the geosynchronous orbit.

  2. Relation between textural and energetic parameters of activated carbon monoliths from coconut shells

    International Nuclear Information System (INIS)

    Vargas, Diana Paola; Giraldo, Liliana; Moreno, Juan C.

    2009-01-01

    Structural characteristics and the energetic parameters of five monoliths of activated carbon were compared. The samples were obtained from coconut shells by means of chemical activation using different concentrations of phosphoric acid. The samples are characterized by means of physical adsorption of N 2 at 77K, CO 2 at 273K, and immersion calorimetry in benzene. From the data obtained the volumes of micropore, mesopore, narrow micro porosity and energy parameters of immersion enthalpy were calculated. Also were calculated, K of the Langmuir model and characteristic energies, Eo, of the Dubinin-Radushkevich model. The experimental results show that the activation with phosphoric acid develops micro porosity, giving a micropore volume between 0,36 and 0,45 cm 3 g-1, area BET between 975 and 1320 m 2 g-1 and immersion enthalpy between 112,9 and 147,7 Jg-1. It was found that for higher BET area, there is a greater immersion enthalpy in benzene, lower characteristic energy and smaller value of K.

  3. Energetic Constraints on H-2-Dependent Terminal Electron Accepting Processes in Anoxic Environments

    DEFF Research Database (Denmark)

    Heimann, Axel Colin; Jakobsen, Rasmus; Blodau, C.

    2010-01-01

    and sulfate reduction are under direct thermodynamic control in soils and sediments and generally approach theoretical minimum energy thresholds. If H-2 concentrations are lowered by thermodynamically more potent TEAPs, these processes are inhibited. This principle is also valid for TEAPS providing more free......Microbially mediated terminal electron accepting processes (TEAPs) to a large extent control the fate of redox reactive elements and associated reactions in anoxic soils, sediments, and aquifers. This review focuses on thermodynamic controls and regulation of H-2-dependent TEAPs, case studies...... illustrating this concept and the quantitative description of thermodynamic controls in modeling. Other electron transfer processes are considered where appropriate. The work reviewed shows that thermodynamics and microbial kinetics are connected near thermodynamic equilibrium. Free energy thresholds...

  4. Research Update: The electronic structure of hybrid perovskite layers and their energetic alignment in devices

    Directory of Open Access Journals (Sweden)

    Selina Olthof

    2016-09-01

    Full Text Available In recent years, the interest in hybrid organic–inorganic perovskites has increased at a rapid pace due to their tremendous success in the field of thin film solar cells. This area closely ties together fundamental solid state research and device application, as it is necessary to understand the basic material properties to optimize the performances and open up new areas of application. In this regard, the energy levels and their respective alignment with adjacent charge transport layers play a crucial role. Currently, we are lacking a detailed understanding about the electronic structure and are struggling to understand what influences the alignment, how it varies, or how it can be intentionally modified. This research update aims at giving an overview over recent results regarding measurements of the electronic structure of hybrid perovskites using photoelectron spectroscopy to summarize the present status.

  5. Energetic electrons at Uranus: Bimodal diffusion in a satellite limited radiation belt

    International Nuclear Information System (INIS)

    Selesnick, R.S.; Stone, E.C.

    1991-01-01

    The Voyager 2 cosmic ray experiment observed intense electron fluxes in the middle magnetosphere of Uranus. High counting rates in several of the solid-state detectors precluded in the normal multiple coincidence analysis used for cosmic ray observations, and the authors have therefore performed laboratory measurements of the single-detector response to electrons. These calibrations allow a deconvolution from the counting rate data of the electron energy spectrum between energies of about 0.7 and 2.5 MeV. They present model fits to the differential intensity spectra from observations between L values of 6 and 15. The spectra are well represented by power laws in kinetic energy with spectral indices between 5 and 7. The phase space density at fixed values of the first two adiabatic invariants generally increases with L, indicative of an external source. However, there are also local minima associated with the satellites Ariel and Umbriel, indicating either a local source or an effective source due to nonconservation of the first two adiabatic invariants. For electrons which mirror at the highest magnetic latitudes, the local minimum associated with Ariel is radically displaced from the minimum L of that satellite by ∼0.5. The latitude variation of the satellite absorption efficiency predicts that if satellite losses are replenished primarily by radial diffusion there should be an increasing pitch angle anisotropy with decreasing L. The uniformity in the observed anisotropy outside the absorption regions then suggests that it is maintained by pitch angle diffusion. The effective source due to pitch angle diffusion is insufficient to cause the phase space density minimum associated with Ariel. Model solutions of the simultaneous radial and pitch angle diffusion equation show that the displacement of the high-latitude Ariel signature is also consistent with a larger effective source

  6. An empirical determination of the production efficiency for auroral 6300 AA emmission by energetic electrons

    International Nuclear Information System (INIS)

    Winningham, J.D.; Bunn, F.E.; Thirkettle, F.W.; Shepherd, G.G.

    1979-06-01

    Auroral data from the Soft Particle Spectrometer and the Red Line Photometer on the ISIS-2 spacecraft have been selected to form an electron energy flux and optical auroral emission data base. The energy fluxes are stored as integrated fluxes over four energy bands, and the corresponding stored optical emission rates are corrected for airglow and for albedo. Because of the variety of electron energy spectra represented in the data base it was possible to perform a regression analysis that yielded the production efficiency for the production of emission for each of the four bands. While the results of this analysis are interesting to compare with theoretical predictions of 6300 AA excitation processes, these statistical results are not as precise as the comparisons of individual experiments where all parameters, such as the atmospheric composition and temperature profiles are measured. The significance of this approach is that it permits a multiparameter description of an electron energy spectrum, and its relationship to a specific optical emission, by purely empirical means. This is particularly useful in the interpretation of ISIS-2 data from the instruments which provided the results, but should find further application in optical-particle auroral studies. (author)

  7. The distribution of infered energetic electron loss with respect to plasmapause location: BARREL results.

    Science.gov (United States)

    Halford, A. J.; Malaspina, D.; Sibeck, D. G.

    2017-12-01

    One of the long outstanding challenges of understanding the inner magnetosphere is accurately describing radiation belt dynamics. This enterprise can seem daunting as many have stated: "if you've seen one storm you've seen one storm". And although much progress has been made over the last half century since the discovery of the radiation belts, there is still ongoing debate about the relative importance of different loss and source mechanisms. Here we will consider one part of radiation belt dynamics, the loss of electrons ( 30 keV to MeV) to the upper atmosphere and endeavor to identify the relative importance of the different loss mechanisms. As demonstrated in often used cartoon diagrams, and previous studies, many radiation belt loss mechanisms such as chorus, hiss, and EMIC waves are thought to have specific MLT and L dependencies as well as dependence on geomagnetic conditions. Many of these loss mechanisms are identifiable through the energies and time scales in which they precipitate electrons. Thus we expect that the observed electron precipiation should follow similar MLT and L patterns as what caused the loss and not show something completely unexpected such as Atlantis rising out of the Columbia River. Here we will examine the location and geomagnetic conditions under which the Balloon Array for Relativistic Radiation Belt Electron Loss (BARREL) inferred radiation belt electron precipitation. The BARREL mission consisted of 4 campaigns, two in Antarctica and 2 in Sweden, for a total of 55 launches. The flights conducted in Antarctica took advantage of the circumpolar winds allowing for the payloads to cross a range of L-values from L > 2.5 onto open field lines, while the Swedish campaigns were held during turn around where the balloons stayed near L = 5.8. We will present the distribution of precipitation with respect to L and MLT as well as with respect to the boundary of the plasmapause as new work has shown that this boundary clearly separates

  8. Gas adsorption, energetics and electronic properties of boron- and nitrogen-doped bilayer graphenes

    Energy Technology Data Exchange (ETDEWEB)

    Fujimoto, Yoshitaka, E-mail: fujimoto@stat.phys.titech.ac.jp [Department of Physics, Tokyo Institute of Technology, Oh-okayama, Meguro-ku, Tokyo 152-8551 (Japan); Saito, Susumu [Department of Physics, Tokyo Institute of Technology, Oh-okayama, Meguro-ku, Tokyo 152-8551 (Japan); International Research Center for Nanoscience and Quantum Physics, Tokyo Institute of Technology, 2-12-1 Oh-okayama, Meguro-ku, Tokyo 152-8551 (Japan); Materials Research Center for Element Strategy, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8503 (Japan)

    2016-10-20

    We study stabilities and electronic properties of several environmental polluting or toxic gas molecules (CO, CO{sub 2}, NO, and NO{sub 2}) adsorbed on B and N atoms in bilayer graphene using first-principles electronic-structure calculations. We find that NO and NO{sub 2} molecules can be bound chemically on B-doped bilayer graphene with large adsorption energies, while CO and CO{sub 2} molecules are not adsorbed chemically on B-doped one. In the case of the N-doped graphene, all four gases do not bind with chemical bonds but adsorb rather physically with small adsorption energies at long distances between gases and graphene. The adsorptions of NO and NO{sub 2} molecules on B-doped bilayer graphene induce the acceptor states above the Fermi energy, and we also find that the charge transfer takes place when the NO and the NO{sub 2} molecules are adsorbed. Thereby, the B-doped bilayer graphene is expected to be useful for NO and NO{sub 2} gas sensor materials.

  9. Theoretical insights into the energetics and electronic properties of MPt{sub 12} (M = Fe, Co, Ni, Cu, and Pd) nanoparticles supported by N-doped defective graphene

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Qing [Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing, 100875 (China); Tian, Yu [College of Chemistry and Chemical Engineering, Harbin Normal University, Harbin, 150025 (China); Chen, Guangju, E-mail: gjchen@bnu.edu.cn [Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing, 100875 (China); Zhao, Jingxiang, E-mail: xjz_hmily@163.com [College of Chemistry and Chemical Engineering, Harbin Normal University, Harbin, 150025 (China)

    2017-03-01

    Highlights: • We studied the deposition of several Pt-based alloy NPs on N-doped defective graphene. • The N-doped graphene can provide anchoring site for Pt-based NPs. • The electronic properties of Pt-based NPs have been greatly modified. • The catalytic properties of Pt-based NPs can be enhanced. - Abstract: Enhancing the catalytic activity and decreasing the usage of Pt catalysts has been a major target in widening their applications for developing proton-exchange membrane fuel cells. In this work, the adsorption energetics, structural features, and electronic properties of several MPt{sub 12} (M = Fe, Co, Ni, Cu, and Pd) nanoparticles (NPs) deposited on N-doped defective graphene were systemically explored by means of comprehensive density functional theory (DFT) computations. The computations revealed that the defective N-doped graphene substrate can provide anchoring site for these Pt-based alloying NPs due to their strong hybridization with the sp{sup 2} dangling bonds at the defect sites of substrate. Especially, these deposited MPt{sub 12} NPs exhibit reduced magnetic moment and their average d-band centers are shifted away from the Fermi level, as compared with the freestanding NPs, leading to the reduction of the adsorption energies of the O species. Thus, the defective N-doped graphene substrate not only enhances the stability of the deposited MPt{sub 12} NPs, but also endows them higher catalytic performance for the oxygen reduction reaction.

  10. Energetics of intrinsic point defects in uranium dioxide from electronic-structure calculations

    International Nuclear Information System (INIS)

    Nerikar, Pankaj; Watanabe, Taku; Tulenko, James S.; Phillpot, Simon R.; Sinnott, Susan B.

    2009-01-01

    The stability range of intrinsic point defects in uranium dioxide is determined as a function of temperature, oxygen partial pressure, and non-stoichiometry. The computational approach integrates high accuracy ab initio electronic-structure calculations and thermodynamic analysis supported by experimental data. In particular, the density functional theory calculations are performed at the level of the spin polarized, generalized gradient approximation and includes the Hubbard U term; as a result they predict the correct anti-ferromagnetic insulating ground state of uranium oxide. The thermodynamic calculations enable the effects of system temperature and partial pressure of oxygen on defect formation energy to be determined. The predicted equilibrium properties and defect formation energies for neutral defect complexes match trends in the experimental literature quite well. In contrast, the predicted values for charged complexes are lower than the measured values. The calculations predict that the formation of oxygen interstitials becomes increasingly difficult as higher temperatures and reducing conditions are approached

  11. Energetic, structural and electronic properties of metal vacancies in strained AlN/GaN interfaces.

    Science.gov (United States)

    Kioseoglou, J; Pontikis, V; Komninou, Ph; Pavloudis, Th; Chen, J; Karakostas, Th

    2015-04-01

    AlN/GaN heterostructures have been studied using density-functional pseudopotential calculations yielding the formation energies of metal vacancies under the influence of local interfacial strains, the associated charge distribution and the energies of vacancy-induced electronic states. Interfaces are built normal to the polar direction of the wurtzite structure by joining two single crystals of AlN and GaN that are a few atomic layers thick; thus, periodic boundary conditions generate two distinct heterophase interfaces. We show that the formation energy of vacancies is a function of their distance from the interfaces: the vacancy-interface interaction is found repulsive or attractive, depending on the type of the interface. When the interaction is attractive, the vacancy formation energy decreases with increasing the associated electric charge, and hence the equilibrium vacancy concentration at the interface is greater. This finding can reveal the well-known morphological differences existing between the two types of investigated interfaces. Moreover, we found that the electric charge is strongly localized around the Ga vacancy, while in the case of Al vacancies is almost uniformly distributed throughout the AlN/GaN heterostructure. Crucially, for the applications of heterostructures, metal vacancies introduce deep states in the calculated bandgap at energy levels from 0.5 to 1 eV above the valence band maximum (VBM). It is, therefore, predicted that vacancies could initiate 'green luminescence' i.e. light emission in the energy range of 2.5 eV stemming from electronic transitions between these extra levels, and the conduction band, or energy levels, due to shallow donors.

  12. Probing the chemistry, electronic structure and redox energetics in pentavalent organometallic actinide complexes

    Energy Technology Data Exchange (ETDEWEB)

    Graves, Christopher R [Los Alamos National Laboratory; Vaughn, Anthony E [Los Alamos National Laboratory; Morris, David E [Los Alamos National Laboratory; Kiplinger, Jaqueline L [Los Alamos National Laboratory

    2008-01-01

    Complexes of the early actinides (Th-Pu) have gained considerable prominence in organometallic chemistry as they have been shown to undergo chemistries not observed with their transition- or lanthanide metal counterparts. Further, while bonding in f-element complexes has historically been considered to be ionic, the issue of covalence remains a subject of debate in the area of actinide science, and studies aimed at elucidating key bonding interactions with 5f-orbitals continue to garner attention. Towards this end, our interests have focused on the role that metal oxidation state plays in the structure, reactivity and spectral properties of organouranium complexes. We report our progress in the synthesis of substituted U{sup V}-imido complexes using various routes: (1) Direct oxidation of U{sup IV}-imido complexes with copper(I) salts; (2) Salt metathesis with U{sup V}-imido halides; (3) Protonolysis and insertion of an U{sup V}-imido alkyl or aryl complex with H-N{double_bond}CPh{sub 2} or N{triple_bond}C-Ph, respectively, to form a U{sup V}-imido ketimide complex. Further, we report and compare the crystallographic, electrochemical, spectroscopic and magnetic characterization of the pentavalent uranium (C{sub 5}Me{sub 5}){sub 2}U({double_bond}N-Ar)(Y) series (Y = OTf, SPh, C{triple_bond}C-Ph, NPh{sub 2}, OPh, N{double_bond}CPh{sub 2}) to further interrogate the molecular, electronic, and magnetic structures of this new class of uranium complexes.

  13. Intensity increase of energetic electrons in the outer radiation belt of the Earth in July 1972 according to data of the ''Prognoz-2'' artificial Earth satellite

    International Nuclear Information System (INIS)

    Blyudov, V.A.; Volodichev, N.N.; Nechaev, O.Yu.; Savenko, I.A.; Saraeva, M.A.; Shavrin, P.I.

    1979-01-01

    Carried out is the investigation of the 6-10 MeV electrons in the outer radiation belt of the Earth at the ''Prognoz-2'' artificial Earth satellite along the trajectory of the satellite motion according to the Mac Ilvain parameter L. With the help of a ternary coincidance telescope in Juny 1972, the formationand decay of the belt of energetic electrons with the maximum intensity in the L=3.7 region was recorded. The maximum fluxer of this belt electrons are estimated. It is supposed that the event recorded is the consequence of the magnetospherical disturbance that occured on 18.4.1972

  14. LARGE SOLAR ENERGETIC PARTICLE EVENTS ASSOCIATED WITH FILAMENT ERUPTIONS OUTSIDE ACTIVE REGIONS

    Energy Technology Data Exchange (ETDEWEB)

    Gopalswamy, N.; Mäkelä, P.; Akiyama, S.; Yashiro, S.; Xie, H.; Thakur, N. [Solar Physics Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Kahler, S. W., E-mail: nat.gopalswamy@nasa.gov [Air Force Research Laboratory, Albuquerque, NM 87117 (United States)

    2015-06-10

    We report on four large filament eruptions (FEs) from solar cycles 23 and 24 that were associated with large solar energetic particle (SEP) events and interplanetary type II radio bursts. The post-eruption arcades corresponded mostly to C-class soft X-ray enhancements, but an M1.0 flare was associated with one event. However, the associated coronal mass ejections (CMEs) were fast (speeds ∼ 1000 km s{sup −1}) and appeared as halo CMEs in the coronagraph field of view. The interplanetary type II radio bursts occurred over a wide wavelength range, indicating the existence of strong shocks throughout the inner heliosphere. No metric type II bursts were present in three events, indicating that the shocks formed beyond 2–3 Rs. In one case, there was a metric type II burst with low starting frequency, indicating a shock formation height of ∼2 Rs. The FE-associated SEP events did have softer spectra (spectral index >4) in the 10–100 MeV range, but there were other low-intensity SEP events with spectral indices ≥4. Some of these events are likely FE-SEP events, but were not classified as such in the literature because they occurred close to active regions. Some were definitely associated with large active region flares, but the shock formation height was large. We definitely find a diminished role for flares and complex type III burst durations in these large SEP events. Fast CMEs and shock formation at larger distances from the Sun seem to be the primary characteristics of the FE-associated SEP events.

  15. Active learners in sustainable electronics and it

    DEFF Research Database (Denmark)

    Schultz, Ole

    This poster-presentation is about active learning in a course sustainable wireless electronics and it. Active learning understood as practical lab-exercises and a team chosen project.......This poster-presentation is about active learning in a course sustainable wireless electronics and it. Active learning understood as practical lab-exercises and a team chosen project....

  16. The energetics of relativistic jets in active galactic nuclei with various kinetic powers

    Science.gov (United States)

    Musoke, Gibwa Rebecca; Young, Andrew; Molnar, Sandor; Birkinshaw, Mark

    2018-01-01

    Numerical simulations are an important tool in understanding the physical processes behind relativistic jets in active galactic nuclei. In such simulations different combinations of intrinsic jet parameters can be used to obtain the same jet kinetic powers. We present a numerical investigation of the effects of varying the jet power on the dynamic and energetic characteristics of the jets for two kinetic power regimes; in the first regime we change the jet density whilst maintaining a fixed velocity, in the second the jet density is held constant while the velocity is varied. We conduct 2D axisymmetric hydrodynamic simulations of bipolar jets propagating through an isothermal cluster atmosphere using the FLASH MHD code in pure hydrodynamics mode. The jets are simulated with kinetic powers ranging between 1045 and 1046 erg/s and internal Mach numbers ranging from 5.6 to 21.5.As the jets begin to propagate into the intracluster medium (ICM), the injected jet energy is converted into the thermal, kinetic and gravitational potential energy components of the jet cocoon and ICM. We explore the temporal evolution of the partitioning of the injected jet energy into the cocoon and the ICM and quantify the importance of entrainment process on the energy partitioning. We investigate the fraction of injected energy transferred to the thermal energy component of the jet-ICM system in the context of heating the cluster environments, noting that the jets simulated display peak thermalisation efficiencies of least 65% and a marked dependence on the jet density. We compare the efficiencies of the energy partitioning between the cocoon and ICM for the two kinetic power regimes and discuss the resulting efficiency-power scaling relations of each regime.

  17. A first principles study of energetics and electronic structural responses of uranium-based coordination polymers to Np incorporation

    International Nuclear Information System (INIS)

    Saha, Saumitra; Becker, Udo

    2018-01-01

    Recently developed coordination polymers (CPs) and metal organic frameworks (MOFs) may find applications in areas such as catalysis, hydrogen storage, and heavy metal immobilization. Research on the potential application of actinide-based CPs (An-CP/MOFs) is not as advanced as transition metal-based MOFs. In order to modify their structures necessary for optimizing thermodynamic and electronic properties, here, we described how a specific topology of a particular actinide-based CP or MOF responds to the incorporation of other actinides considering their diverse coordination chemistry associated with the multiple valence states and charge-balancing mechanisms. In this study, we apply a recently developed DFT-based method to determine the relative stability of transuranium incorporated CPs in comparison to their uranium counterpart considering both solid and aqueous state sources and sinks to understand the mechanism and energetics of charge-balanced Np 5+ incorporation into three uranium-based CPs. The calculated Np 5+ + H + incorporation energies for these CPs range from 0.33 to 0.52 eV, depending on the organic linker, when using the solid oxide Np source Np 2 O 5 and U sink UO 3 . Incorporation energies of these CPs using aqueous sources and sinks increase to 2.85-3.14 eV. The thermodynamic and structural analysis in this study aides in determining, why certain MOF topologies and ligands are selective for some actinides and not for others. This means that once this method is extended across a variety of CPs with their respective linker molecules and different actinides, it can be used to identify certain CPs with certain organic ligands being specific for certain actinides. This information can be used to construct CPs for actinide separation. This is the first determination of the electronic structure (band structure, density of states) of these uranium- and transuranium-based CPs which may eventually lead to design CPs with certain optical or catalytic

  18. A first principles study of energetics and electronic structural responses of uranium-based coordination polymers to Np incorporation

    Energy Technology Data Exchange (ETDEWEB)

    Saha, Saumitra [Melbourne Univ., VIC (Australia). Australian Research Council Centre of Excellence for Advanced Molecular Imaging; Becker, Udo [Michigan Univ., Ann Arbor, MI (United States). Dept. of Earth and Environmental Sciences

    2018-04-01

    Recently developed coordination polymers (CPs) and metal organic frameworks (MOFs) may find applications in areas such as catalysis, hydrogen storage, and heavy metal immobilization. Research on the potential application of actinide-based CPs (An-CP/MOFs) is not as advanced as transition metal-based MOFs. In order to modify their structures necessary for optimizing thermodynamic and electronic properties, here, we described how a specific topology of a particular actinide-based CP or MOF responds to the incorporation of other actinides considering their diverse coordination chemistry associated with the multiple valence states and charge-balancing mechanisms. In this study, we apply a recently developed DFT-based method to determine the relative stability of transuranium incorporated CPs in comparison to their uranium counterpart considering both solid and aqueous state sources and sinks to understand the mechanism and energetics of charge-balanced Np{sup 5+} incorporation into three uranium-based CPs. The calculated Np{sup 5+} + H{sup +} incorporation energies for these CPs range from 0.33 to 0.52 eV, depending on the organic linker, when using the solid oxide Np source Np{sub 2}O{sub 5} and U sink UO{sub 3}. Incorporation energies of these CPs using aqueous sources and sinks increase to 2.85-3.14 eV. The thermodynamic and structural analysis in this study aides in determining, why certain MOF topologies and ligands are selective for some actinides and not for others. This means that once this method is extended across a variety of CPs with their respective linker molecules and different actinides, it can be used to identify certain CPs with certain organic ligands being specific for certain actinides. This information can be used to construct CPs for actinide separation. This is the first determination of the electronic structure (band structure, density of states) of these uranium- and transuranium-based CPs which may eventually lead to design CPs with certain

  19. Energetic performance is improved by specific activation of K+ fluxes through K(Ca) channels in heart mitochondria

    DEFF Research Database (Denmark)

    Aon, Miguel A; Cortassa, Sonia; Wei, An-Chi

    2009-01-01

    Mitochondrial volume regulation depends on K+ movement across the inner membrane and a mitochondrial Ca2+-dependent K+ channel (mitoK(Ca)) reportedly contributes to mitochondrial K+ uniporter activity. Here we utilize a novel K(Ca) channel activator, NS11021, to examine the role of mito...... similar nonspecific (toxin-insensitive) effects at high concentrations. The results indicate that activating K+ flux through mitoK(Ca) mediates a beneficial effect on energetics that depends on mitochondrial swelling with maintained DeltaPsi(m)....

  20. Energetic basis of catalytic activity of layered nanophase calcium manganese oxides for water oxidation.

    Science.gov (United States)

    Birkner, Nancy; Nayeri, Sara; Pashaei, Babak; Najafpour, Mohammad Mahdi; Casey, William H; Navrotsky, Alexandra

    2013-05-28

    Previous measurements show that calcium manganese oxide nanoparticles are better water oxidation catalysts than binary manganese oxides (Mn3O4, Mn2O3, and MnO2). The probable reasons for such enhancement involve a combination of factors: The calcium manganese oxide materials have a layered structure with considerable thermodynamic stability and a high surface area, their low surface energy suggests relatively loose binding of H2O on the internal and external surfaces, and they possess mixed-valent manganese with internal oxidation enthalpy independent of the Mn(3+)/Mn(4+) ratio and much smaller in magnitude than the Mn2O3-MnO2 couple. These factors enhance catalytic ability by providing easy access for solutes and water to active sites and facile electron transfer between manganese in different oxidation states.

  1. The nonlinear gyroresonance interaction between energetic electrons and coherent VLF waves propagating at an arbitrary angle with respect to the earth's magnetic field

    Science.gov (United States)

    Bell, T. F.

    1984-01-01

    A theory is presented of the nonlinear gyroresonance interaction that takes place in the magnetosphere between energetic electrons and coherent VLF waves propagating in the whistler mode at an arbitrary angle psi with respect to the earth's magnetic field B-sub-0. Particularly examined is the phase trapping (PT) mechanism believed to be responsible for the generation of VLF emissions. It is concluded that near the magnetic equatorial plane gradients of psi may play a very important part in the PT process for nonducted waves. Predictions of a higher threshold value for PT for nonducted waves generally agree with experimental data concerning VLF emission triggering by nonducted waves.

  2. Hydroxycinnamic acids used as external acceptors of electrons: an energetic advantage for strictly heterofermentative lactic acid bacteria.

    Science.gov (United States)

    Filannino, Pasquale; Gobbetti, Marco; De Angelis, Maria; Di Cagno, Raffaella

    2014-12-01

    The metabolism of hydroxycinnamic acids by strictly heterofermentative lactic acid bacteria (19 strains) was investigated as a potential alternative energy route. Lactobacillus curvatus PE5 was the most tolerant to hydroxycinnamic acids, followed by strains of Weissella spp., Lactobacillus brevis, Lactobacillus fermentum, and Leuconostoc mesenteroides, for which the MIC values were the same. The highest sensitivity was found for Lactobacillus rossiae strains. During growth in MRS broth, lactic acid bacteria reduced caffeic, p-coumaric, and ferulic acids into dihydrocaffeic, phloretic, and dihydroferulic acids, respectively, or decarboxylated hydroxycinnamic acids into the corresponding vinyl derivatives and then reduced the latter compounds to ethyl compounds. Reductase activities mainly emerged, and the activities of selected strains were further investigated in chemically defined basal medium (CDM) under anaerobic conditions. The end products of carbon metabolism were quantified, as were the levels of intracellular ATP and the NAD(+)/NADH ratio. Electron and carbon balances and theoretical ATP/glucose yields were also estimated. When CDM was supplemented with hydroxycinnamic acids, the synthesis of ethanol decreased and the concentration of acetic acid increased. The levels of these metabolites reflected on the alcohol dehydrogenase and acetate kinase activities. Overall, some biochemical traits distinguished the common metabolism of strictly heterofermentative strains: main reductase activity toward hydroxycinnamic acids, a shift from alcohol dehydrogenase to acetate kinase activities, an increase in the NAD(+)/NADH ratio, and the accumulation of supplementary intracellular ATP. Taken together, the above-described metabolic responses suggest that strictly heterofermentative lactic acid bacteria mainly use hydroxycinnamic acids as external acceptors of electrons. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

  3. Fast-ion response to energetic-particle-driven MHD activity in Heliotron J

    Energy Technology Data Exchange (ETDEWEB)

    Kobayashi, S.; Yamamoto, S.; Mizuuchi, T.; Nagasaki, K.; Okada, H.; Minami, T.; Hanatani, K.; Konoshima, S.; Ohshima, S.; Toushi, K.; Sano, F. [Institute of Advanced Energy, Kyoto University, Gokasho, Uji (Japan); Nagaoka, K.; Suzuki, Y.; Takeiri, Y.; Yokoyama, M. [National Institute for Fusion Science, Toki, Gifu (Japan); Murakami, S. [Graduate School of Engineering, Kyoto University, Kyoto (Japan); Lee, H.Y.; Nakamura, Y.; Hosaka, K. [Graduate School of Energy Science, Kyoto University, Gokasho, Uji (Japan)

    2010-08-15

    In Heliotron J, low magnetic shear configuration, instabilities with frequency chirping in the frequency range of Alfven eigenmodes have been observed in tangentially injected neutral beam plasmas. These modes are induced by energetic-particle driven magnetohydrodynamic (MHD) instabilities such as global Alfven eigenmode or energetic particle mode. A hybrid directional Langmuir probe system has been installed into Heliotron J to investigate the response of fast-ion fluxes to the MHD modes. A high coherent response of the ion flux to the bursting modes has been observed not only by the co-directed probe but also by the counter-directed one. A linear correlation between the response of the co-directed ion flux and the mode amplitude has been found. The radial profile of the response of the co-directed ions has decreased with the minor radius and has not been obtained significantly outside last closed flux surface. These results indicate that the fast-ion response is due to a resonant convective oscillation. The ion flux response of the counter-directed probe has appeared in the growth phase of the mode burst. Its phase relation is different from that of co-directed one and magnetic probe located at the Heliotron J vacuum vessel. Two candidates of the detected ion flux of the counter-directed probe have been discussed. (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  4. The role of astrocytic glycogen in supporting the energetics of neuronal activity.

    Science.gov (United States)

    Dinuzzo, Mauro; Mangia, Silvia; Maraviglia, Bruno; Giove, Federico

    2012-11-01

    Energy homeostasis in the brain is maintained by oxidative metabolism of glucose, primarily to fulfil the energy demand associated with ionic movements in neurons and astrocytes. In this contribution we review the experimental evidence that grounds a specific role of glycogen metabolism in supporting the functional energetic needs of astrocytes during the removal of extracellular potassium. Based on theoretical considerations, we further discuss the hypothesis that the mobilization of glycogen in astrocytes serves the purpose to enhance the availability of glucose for neuronal glycolytic and oxidative metabolism at the onset of stimulation. Finally, we provide an evolutionary perspective for explaining the selection of glycogen as carbohydrate reserve in the energy-sensing machinery of cell metabolism.

  5. Electronic charge transfer in cobalt doped fullerene thin films and effect of energetic ion impacts by x-ray absorption spectroscopy

    International Nuclear Information System (INIS)

    Thakur, P.; Kumar, Amit; Gautam, S.; Chae, K.H.

    2011-01-01

    We report on the electronic charge transfer in cobalt doped fullerene thin films by means of near-edge x-ray-absorption fine structure (NEXAFS) spectroscopy measurement. Co-doped fullerene films were prepared by co-deposition technique and subjected to energetic ion irradiation (120 MeV Au) for possibly alignment or interconnect of randomly distributed metal particles. Polarization dependent NEXAFS spectra revealed the alignment of Co and C atoms along the irradiated ionic path. The structural changes in Co-doped as-deposited and ion irradiated fullerene films were investigated by means of Raman spectroscopy measurements. Downshift of pentagonal pinch mode A g (2) in Raman spectroscopy indicated the electronic charge transfer from Co atom to fullerene molecules, which is further confirmed by NEXAFS at C K-edge for Co-doped fullerene films.

  6. A pulsed, mono-energetic and angular-selective UV photo-electron source for the commissioning of the KATRIN experiment

    Energy Technology Data Exchange (ETDEWEB)

    Behrens, J. [Institut fuer Kernphysik, WWU Muenster, Muenster (Germany); Karlsruhe Institute of Technology, IEKP, Eggenstein-Leopoldshafen (Germany); Ranitzsch, P.C.O.; Hannen, V.; Ortjohann, H.W.; Rest, O.; Winzen, D.; Zacher, M.; Weinheimer, C. [Institut fuer Kernphysik, WWU Muenster, Muenster (Germany); Beck, M. [Institut fuer Kernphysik, WWU Muenster, Muenster (Germany); Johannes-Gutenberg Universitaet, Institut fuer Physik, Mainz (Germany); Beglarian, A. [Karlsruhe Institute of Technology, IPE, Eggenstein-Leopoldshafen (Germany); Erhard, M.; Groh, S.; Kraus, M. [IEKP, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen (Germany); Schloesser, K.; Thuemmler, T. [Karlsruhe Institute of Technology, IKP, Karlsruhe (Germany); Valerius, K. [Institut fuer Kernphysik, WWU Muenster, Muenster (Germany); Karlsruhe Institute of Technology, IKP, Karlsruhe (Germany); Wierman, K.; Wilkerson, J.F. [University of North Carolina, Department of Physics and Astronomy, Chapel Hill, NC (United States)

    2017-06-15

    The KATRIN experiment aims to determine the neutrino mass scale with a sensitivity of 200 meV/c{sup 2} (90% C.L.) by a precision measurement of the shape of the tritium β-spectrum in the endpoint region. The energy analysis of the decay electrons is achieved by a MAC-E filter spectrometer. To determine the transmission properties of the KATRIN main spectrometer, a mono-energetic and angular-selective electron source has been developed. In preparation for the second commissioning phase of the main spectrometer, a measurement phase was carried out at the KATRIN monitor spectrometer where the device was operated in a MAC-E filter setup for testing. The results of these measurements are compared with simulations using the particle-tracking software ''Kassiopeia'', which was developed in the KATRIN collaboration over recent years. (orig.)

  7. Energetic map

    International Nuclear Information System (INIS)

    2012-01-01

    This report explains the energetic map of Uruguay as well as the different systems that delimits political frontiers in the region. The electrical system importance is due to the electricity, oil and derived , natural gas, potential study, biofuels, wind and solar energy

  8. Energetics of Ortho-7 (oxime drug translocation through the active-site gorge of tabun conjugated acetylcholinesterase.

    Directory of Open Access Journals (Sweden)

    Vivek Sinha

    Full Text Available Oxime drugs translocate through the 20 Å active-site gorge of acetylcholinesterase in order to liberate the enzyme from organophosphorus compounds' (such as tabun conjugation. Here we report bidirectional steered molecular dynamics simulations of oxime drug (Ortho-7 translocation through the gorge of tabun intoxicated enzyme, in which time dependent external forces accelerate the translocation event. The simulations reveal the participation of drug-enzyme hydrogen bonding, hydrophobic interactions and water bridges between them. Employing nonequilibrium theorems that recovers the free energy from irreversible work done, we reconstruct potential of mean force along the translocation pathway such that the desired quantity represents an unperturbed system. The potential locates the binding sites and barriers for the drug to translocate inside the gorge. Configurational entropic contribution of the protein-drug binding entity and the role of solvent translational mobility in the binding energetics is further assessed.

  9. Bi-layer structure of counterstreaming energetic electron fluxes: a diagnostic tool of the acceleration mechanism in the Earth's magnetotail

    Directory of Open Access Journals (Sweden)

    D. V. Sarafopoulos

    2010-02-01

    Full Text Available For the first time we identify a bi-layer structure of energetic electron fluxes in the Earth's magnetotail and establish (using datasets mainly obtained by the Geotail Energetic Particles and Ion Composition (EPIC/ICS instrument that it actually provides strong evidence for a purely spatial structure. Each bi-layer event is composed of two distinct layers with counterstreaming energetic electron fluxes, parallel and antiparallel to the local ambient magnetic field lines; in particular, the tailward directed fluxes always occur in a region adjacent to the lobes. Adopting the X-line as a standard reconnection model, we determine the occurrence of bi-layer events relatively to the neutral point, in the substorm frame; four (out of the shown seven events are observed earthward and three tailward, a result implying that four events probably occurred with the substorm's local recovery phase. We discuss the bi-layer events in terms of the X-line model; they add more constraints for any candidate electron acceleration mechanism. It should be stressed that until this time, none proposed electron acceleration mechanism has discussed or predicted these layered structures with all their properties. Then we discuss the bi-layer events in terms of the much promising "akis model", as introduced by Sarafopoulos (2008. The akis magnetic field topology is embedded in a thinned plasma sheet and is potentially causing charge separation. We assume that as the Rc curvature radius of the magnetic field line tends to become equal to the ion gyroradius rg, then the ions become non-adiabatic. At the limit Rc=rg the demagnetization process is also under way and the frozen-in magnetic field condition is violated by strong wave turbulence; hence, the ion particles in this geometry are stochastically scattered. In addition, ion diffusion probably takes place across the magnetic field, since an

  10. Flare energetics

    Science.gov (United States)

    Wu, S. T.; Dejager, C.; Dennis, B. R.; Hudson, H. S.; Simnett, G. M.; Strong, K. T.; Bentley, R. D.; Bornmann, P. L.; Bruner, M. E.; Cargill, P. J.

    1986-01-01

    In this investigation of flare energetics, researchers sought to establish a comprehensive and self-consistent picture of the sources and transport of energy within a flare. To achieve this goal, they chose five flares in 1980 that were well observed with instruments on the Solar Maximum Mission, and with other space-borne and ground-based instruments. The events were chosen to represent various types of flares. Details of the observations available for them and the corresponding physical parameters derived from these data are presented. The flares were studied from two perspectives, the impulsive and gradual phases, and then the results were compared to obtain the overall picture of the energics of these flares. The role that modeling can play in estimating the total energy of a flare when the observationally determined parameters are used as the input to a numerical model is discussed. Finally, a critique of the current understanding of flare energetics and the methods used to determine various energetics terms is outlined, and possible future directions of research in this area are suggested.

  11. INVERSE ELECTRON TRANSFER IN PEROXYOXALATE CHEMIEXCITATION USING EASILY REDUCIBLE ACTIVATORS

    NARCIS (Netherlands)

    Bartoloni, Fernando Heering; Monteiro Leite Ciscato, Luiz Francisco; Augusto, Felipe Alberto; Baader, Wilhelm Josef

    2010-01-01

    INVERSE ELECTRON TRANSFER IN PEROXYOXALATE CHEMIEXCITATION USING EASILY REDUCIBLE ACTIVATORS. Chemiluminescence properties of the peroxyoxalate reaction in the presence of activators bearing electron withdrawing substituents were studied, to evaluate the possible occurrence of an inverse electron

  12. Excitation of high-frequency electromagnetic waves by energetic electrons with a loss cone distribution in a field-aligned potential drop

    Science.gov (United States)

    Fung, Shing F.; Vinas, Adolfo F.

    1994-01-01

    The electron cyclotron maser instability (CMI) driven by momentum space anisotropy (df/dp (sub perpendicular) greater than 0) has been invoked to explain many aspects, such as the modes of propagation, harmonic emissions, and the source characteristics of the auroral kilometric radiation (AKR). Recent satellite observations of AKR sources indicate that the source regions are often imbedded within the auroral acceleration region characterized by the presence of a field-aligned potential drop. In this paper we investigate the excitation of the fundamental extraordinary mode radiation due to the accelerated electrons. The momentum space distribution of these energetic electrons is modeled by a realistic upward loss cone as modified by the presence of a parallel potential drop below the observation point. On the basis of linear growth rate calculations we present the emission characteristics, such as the frequency spectrum and the emission angular distribution as functions of the plasma parameters. We will discuss the implication of our results on the generation of the AKR from the edges of the auroral density cavities.

  13. Interaction of silicene with β-Si3N4(0001)/Si(111) substrate; energetics and electronic properties

    International Nuclear Information System (INIS)

    Filippone, Francesco

    2014-01-01

    The free-standing, quasi-2D layer of Si is known as silicene, in analogy with graphene. Much effort is devoted in the study of silicene, since, similarly to graphene, it shows a very high electron mobility. The interaction of silicene with a hybrid substrate, β-Si 3 N 4 (0001)/Si(111), exposing the β-Si 3 N 4 (0001) surface, has been studied by means of Density Functional calculations, with van der Waals interactions included. Once deepened the most important structural and electronic features of the hybrid substrate, we demonstrated that an electron transfer occurs from the substrate to the silicene layer. In turn, such an electron transfer can be modulated by the doping of the substrate. The β-Si 3 N 4 /silicene interaction appears to be strong enough to ensure adequate adsorption stability. It is also shown that electronic states of substrate and adsorbate still remain decoupled, paving the way for the exploitation of the peculiar electron mobility properties of the silicene layer. A detailed analysis in both direct and reciprocal space is reported. (paper)

  14. Amine oxidase from lentil seedlings: energetic domains and effect of temperature on activity.

    Science.gov (United States)

    Moosavi-Nejad, S Z; Rezaei-Tavirani, M; Padiglia, A; Floris, G; Moosavi-Movahedi, A A

    2001-07-01

    Copper/TPQ amine oxidases from mammalian and plant sources have shown many differences in substrate specificity and molecular properties. In this work the activity of lentil seedling amine oxidase was followed at various temperatures in 100 mM potassium phosphate buffer, pH 7, using benzylamine as substrate. The discontinuous Arrhenius plot of lentil amine oxidase showed two distinct phases with a jump between them. Thermal denaturation of the enzyme, using differential scanning calorimetry under the same experimental conditions, showed a transition at the same temperature ranges in the absence of substrate, indicating the occurrence of conformational changes, with an enthalpy change of about 175.9 kJ/mole. The temperature-induced changes of the activity of lentil amine oxidase are compared with those of bovine serum amine oxidase (taken from the literature).

  15. The AFIS experiment: Detecting low energetic antiprotons in a low earth orbit, using an active target detector

    Energy Technology Data Exchange (ETDEWEB)

    Poeschl, Thomas; Gaisbauer, Dominic; Greenwald, Daniel; Hahn, Alexander; Hauptmann, Philipp; Konorov, Igor; Meng, Lingxin; Paul, Stephan [Physics Department E18, Technische Universitaet Muenchen (Germany); Losekamm, Martin [Physics Department E18, Technische Universitaet Muenchen (Germany); Institute of Astronautics, Technische Universitaet Muenchen (Germany); Renker, Dieter [Physics Department E17, Technische Universitaet Muenchen (Germany)

    2014-07-01

    Since the first observation of geomagnetically trapped antiprotons by the PAMELA experiment and the new results on the positron excess by the AMS-02 experiment, the creation and transport of antimatter in the Earth's upper atmosphere attracts more and more attention both at theoretical and experimental side. For this reason the AFIS experiment was initiated to measure the flux of low energetic antiprotons in the South Atlantic Anomaly (SAA). We developed an active target detector made from scintillating fibers connected to silicon photomultipliers which allows to detect antiprotons in the energy interval of about 30 MeV-100 MeV. The stopping curve of incoming antiprotons (Bragg peak) and the signal of outgoing pions created from the annihilation, are used for particle identification as well as triggering. We plan to implement this detector on a 3 unit cubesat satellite in the framework the 'Move2Warp' mission, which is carried out as a student project by the Technische Universitaet Muenchen.

  16. Study and modeling of the most energetic Active Galactic Nuclei with the Fermi satellite

    International Nuclear Information System (INIS)

    Sanchez, D.

    2010-06-01

    The Fermi satellite was launched in June 2008. The onboard LAT detector is dedicated to the study of galactic and extra-galactic gamma sources with an energy comprised between 200 MeV and 300 GeV. 1451 sources have been detected in less than 11 months. This document is divided into 6 chapters: 1) gamma astronomy, 2) the Fermi satellite, 3) the active galactic nuclei (NAG), 4) the observation of several blazars (PKS-2155-304 and PG-1553+113) and its simulation, 5) the observation of PKS-2155-304 with both RXTE and Fermi, and 6) conclusion

  17. Hydrodynamics-based functional forms of activity metabolism: a case for the power-law polynomial function in animal swimming energetics.

    Science.gov (United States)

    Papadopoulos, Anthony

    2009-01-01

    The first-degree power-law polynomial function is frequently used to describe activity metabolism for steady swimming animals. This function has been used in hydrodynamics-based metabolic studies to evaluate important parameters of energetic costs, such as the standard metabolic rate and the drag power indices. In theory, however, the power-law polynomial function of any degree greater than one can be used to describe activity metabolism for steady swimming animals. In fact, activity metabolism has been described by the conventional exponential function and the cubic polynomial function, although only the power-law polynomial function models drag power since it conforms to hydrodynamic laws. Consequently, the first-degree power-law polynomial function yields incorrect parameter values of energetic costs if activity metabolism is governed by the power-law polynomial function of any degree greater than one. This issue is important in bioenergetics because correct comparisons of energetic costs among different steady swimming animals cannot be made unless the degree of the power-law polynomial function derives from activity metabolism. In other words, a hydrodynamics-based functional form of activity metabolism is a power-law polynomial function of any degree greater than or equal to one. Therefore, the degree of the power-law polynomial function should be treated as a parameter, not as a constant. This new treatment not only conforms to hydrodynamic laws, but also ensures correct comparisons of energetic costs among different steady swimming animals. Furthermore, the exponential power-law function, which is a new hydrodynamics-based functional form of activity metabolism, is a special case of the power-law polynomial function. Hence, the link between the hydrodynamics of steady swimming and the exponential-based metabolic model is defined.

  18. Hydrodynamics-based functional forms of activity metabolism: a case for the power-law polynomial function in animal swimming energetics.

    Directory of Open Access Journals (Sweden)

    Anthony Papadopoulos

    Full Text Available The first-degree power-law polynomial function is frequently used to describe activity metabolism for steady swimming animals. This function has been used in hydrodynamics-based metabolic studies to evaluate important parameters of energetic costs, such as the standard metabolic rate and the drag power indices. In theory, however, the power-law polynomial function of any degree greater than one can be used to describe activity metabolism for steady swimming animals. In fact, activity metabolism has been described by the conventional exponential function and the cubic polynomial function, although only the power-law polynomial function models drag power since it conforms to hydrodynamic laws. Consequently, the first-degree power-law polynomial function yields incorrect parameter values of energetic costs if activity metabolism is governed by the power-law polynomial function of any degree greater than one. This issue is important in bioenergetics because correct comparisons of energetic costs among different steady swimming animals cannot be made unless the degree of the power-law polynomial function derives from activity metabolism. In other words, a hydrodynamics-based functional form of activity metabolism is a power-law polynomial function of any degree greater than or equal to one. Therefore, the degree of the power-law polynomial function should be treated as a parameter, not as a constant. This new treatment not only conforms to hydrodynamic laws, but also ensures correct comparisons of energetic costs among different steady swimming animals. Furthermore, the exponential power-law function, which is a new hydrodynamics-based functional form of activity metabolism, is a special case of the power-law polynomial function. Hence, the link between the hydrodynamics of steady swimming and the exponential-based metabolic model is defined.

  19. Active pixel sensor array with electronic shuttering

    Science.gov (United States)

    Fossum, Eric R. (Inventor)

    2002-01-01

    An active pixel cell includes electronic shuttering capability. The cell can be shuttered to prevent additional charge accumulation. One mode transfers the current charge to a storage node that is blocked against accumulation of optical radiation. The charge is sampled from a floating node. Since the charge is stored, the node can be sampled at the beginning and the end of every cycle. Another aspect allows charge to spill out of the well whenever the charge amount gets higher than some amount, thereby providing anti blooming.

  20. Ab initio configuration interaction study on the energetics and electronic structure of the 1-52Σ+ and 1-32Π states of CS+

    International Nuclear Information System (INIS)

    Honjou, Nobumitsu

    2006-01-01

    The energetics and electronic structure of the 1-5 2 Σ + and 1-3 2 Π states of CS + at and around the equilibrium internuclear distance R e for the CS X 1 Σ + state are studied by carrying out ab initio configuration interaction (CI) calculations. The spectroscopic constants of T e , ω e , and R e for the 1-4 2 Σ + , 1 2 Π, and 3 2 Π states are evaluated from the CI potential energy curves (PECs). The avoided crossing between the 2-3 2 Σ + PECs causes the 3 2 Σ + minimum and explains the observed high intensities for the photoionization from the CS X 1 Σ + state to both the 2-3 2 Σ + states. The avoided crossing between the 3-4 2 Σ + PECs produces the 3 2 Σ + maximum and 4 2 Σ + well minimum. The avoided crossing between the 2-3 2 Π PECs results in the 3 2 Π minimum and a small minimum spacing (0.14 eV) between the PECs

  1. Energetic and electronic computation of the two-hydrogen atom donation process in catecholic and non-catecholic anthocyanidins.

    Science.gov (United States)

    Ali, Hussein M; Ali, Isra H

    2018-03-15

    Antioxidant activity of anthocyanidins is greatly affected by the 3-hydroxyl group and/or a catecholic moiety. The two-hydrogen atom donation process is frequently used to explain the high antioxidant activity of polyphenolic compounds leading to the formation of stable diketones e.g. 1,2-quinones. Thermodynamic parameters, HOMO and spin density were computed to identify the favoured path, either through the 3-hydroxyl group or through the catecholic moiety in a series of catecholic and non-catecholic 3-oxy- (and deoxy)-anthocyanidins. DFT calculations showed that the donation process in non-catecholic anthocyanidins depended on the substituents on ring B. Anthocyanidins with 3',5'-diOMe groups showed donation through 3,4'-OH or, otherwise, through 3,5-OH groups. Catecholic 3-oxyanthocyanidins, on the other hand, showed donation through the 3,4'-OH path rather than the catecholic path (4',3'-path). The 3,4'-path was favoured by the formation of planar 3-radicals in the first step and the stabilization of 4'-radicals in the second step by H-bonding with the 3'-OH group. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Active electronic personal dosemeter in interventional radiology

    International Nuclear Information System (INIS)

    Prlic, I.; Suric Mihic, M.; Vucic, Z.

    2008-01-01

    A recently developed active electronic personal dosemeter (AEPD) was utilised in order to measure the levels and the structure of occupational exposure to scattered X-ray radiation of medical staff who performed percutaneous revascularisation therapy that involves interventional radiology (IR) on the pelvis and upper leg arteries. The AEPDs, placed on the operators' and assistants' chests, that is, above the protective apron, continuously measured and recorded the received doses and, as a novelty, dose rates as a function of time, thus yielding a unique record of occupational doses and dose rates pattern at the working place. This paper presents and discusses one typical daily pattern in which seven percutaneous interventions were performed. (authors)

  3. Parametric excitation of very low frequency (VLF) electromagnetic whistler waves and interaction with energetic electrons in radiation belt

    Science.gov (United States)

    Sotnikov, V.; Kim, T.; Caplinger, J.; Main, D.; Mishin, E.; Gershenzon, N.; Genoni, T.; Paraschiv, I.; Rose, D.

    2018-04-01

    The concept of a parametric antenna in ionospheric plasma is analyzed. Such antennas are capable of exciting electromagnetic radiation fields, specifically the creation of whistler waves generated at the very low frequency (VLF) range, which are also capable of propagating large distances away from the source region. The mechanism of whistler wave generation is considered a parametric interaction of quasi-electrostatic whistler waves (also known as low oblique resonance (LOR) oscillations) excited by a conventional loop antenna. The interaction of LOR waves with quasi-neutral density perturbations in the near field of an antenna gives rise to electromagnetic whistler waves on combination frequencies. It is shown in this work that the amplitude of these waves can considerably exceed the amplitude of whistler waves directly excited by a loop. Additionally, particle-in-cell simulations, which demonstrate the excitation and spatial structure of VLF waves excited by a loop antenna, are presented. Possible applications including the wave-particle interactions to mitigate performance anomalies of low Earth orbit satellites, active space experiments, communication via VLF waves, and modification experiments in the ionosphere will be discussed.

  4. Assessment of energetic costs of AhR activation by β-naphthoflavone in rainbow trout (Oncorhynchus mykiss) hepatocytes using metabolic flux analysis

    International Nuclear Information System (INIS)

    Nault, Rance; Abdul-Fattah, Hiba; Mironov, Gleb G.; Berezovski, Maxim V.; Moon, Thomas W.

    2013-01-01

    Exposure to environmental contaminants such as activators of the aryl hydrocarbon receptor (AhR) leads to the induction of defense and detoxification mechanisms. While these mechanisms allow organisms to metabolize and excrete at least some of these environmental contaminants, it has been proposed that these mechanisms lead to significant energetic challenges. This study tests the hypothesis that activation of the AhR by the model agonist β-naphthoflavone (βNF) results in increased energetic costs in rainbow trout (Oncorhynchus mykiss) hepatocytes. To address this hypothesis, we employed traditional biochemical approaches to examine energy allocation and metabolism including the adenylate energy charge (AEC), protein synthesis rates, Na + /K + -ATPase activity, and enzyme activities. Moreover, we have used for the first time in a fish cell preparation, metabolic flux analysis (MFA) an in silico approach for the estimation of intracellular metabolic fluxes. Exposure of trout hepatocytes to 1 μM βNF for 48 h did not alter hepatocyte AEC, protein synthesis, or Na + /K + -ATPase activity but did lead to sparing of glycogen reserves and changes in activities of alanine aminotransferase and citrate synthase suggesting altered metabolism. Conversely, MFA did not identify altered metabolic fluxes, although we do show that the dynamic metabolism of isolated trout hepatocytes poses a significant challenge for this type of approach which should be considered in future studies. - Highlights: • Energetic costs of AhR activation by βNF was examined in rainbow trout hepatocytes. • Metabolic flux analysis was performed on a fish cell preparation for the first time. • Exposure to βNF led to sparing of glycogen reserves and altered enzyme activities. • Adenylate energy charge was maintained despite temporal changes in metabolism

  5. Assessment of energetic costs of AhR activation by β-naphthoflavone in rainbow trout (Oncorhynchus mykiss) hepatocytes using metabolic flux analysis

    Energy Technology Data Exchange (ETDEWEB)

    Nault, Rance, E-mail: naultran@msu.edu [Ottawa-Carleton Institute of Biology, Department of Biology and Centre for Advanced Research in Environmental Genomics, University of Ottawa, Ottawa, Ontario, K1N 6N5 (Canada); Abdul-Fattah, Hiba [Ottawa-Carleton Institute of Biology, Department of Biology and Centre for Advanced Research in Environmental Genomics, University of Ottawa, Ottawa, Ontario, K1N 6N5 (Canada); Mironov, Gleb G.; Berezovski, Maxim V. [Ottawa-Carleton Institute of Biology, Department of Biology and Centre for Advanced Research in Environmental Genomics, University of Ottawa, Ottawa, Ontario, K1N 6N5 (Canada); Department of Chemistry, University of Ottawa, Ottawa, Ontario, K1N 6N5 (Canada); Moon, Thomas W. [Ottawa-Carleton Institute of Biology, Department of Biology and Centre for Advanced Research in Environmental Genomics, University of Ottawa, Ottawa, Ontario, K1N 6N5 (Canada)

    2013-08-15

    Exposure to environmental contaminants such as activators of the aryl hydrocarbon receptor (AhR) leads to the induction of defense and detoxification mechanisms. While these mechanisms allow organisms to metabolize and excrete at least some of these environmental contaminants, it has been proposed that these mechanisms lead to significant energetic challenges. This study tests the hypothesis that activation of the AhR by the model agonist β-naphthoflavone (βNF) results in increased energetic costs in rainbow trout (Oncorhynchus mykiss) hepatocytes. To address this hypothesis, we employed traditional biochemical approaches to examine energy allocation and metabolism including the adenylate energy charge (AEC), protein synthesis rates, Na{sup +}/K{sup +}-ATPase activity, and enzyme activities. Moreover, we have used for the first time in a fish cell preparation, metabolic flux analysis (MFA) an in silico approach for the estimation of intracellular metabolic fluxes. Exposure of trout hepatocytes to 1 μM βNF for 48 h did not alter hepatocyte AEC, protein synthesis, or Na{sup +}/K{sup +}-ATPase activity but did lead to sparing of glycogen reserves and changes in activities of alanine aminotransferase and citrate synthase suggesting altered metabolism. Conversely, MFA did not identify altered metabolic fluxes, although we do show that the dynamic metabolism of isolated trout hepatocytes poses a significant challenge for this type of approach which should be considered in future studies. - Highlights: • Energetic costs of AhR activation by βNF was examined in rainbow trout hepatocytes. • Metabolic flux analysis was performed on a fish cell preparation for the first time. • Exposure to βNF led to sparing of glycogen reserves and altered enzyme activities. • Adenylate energy charge was maintained despite temporal changes in metabolism.

  6. Toxicology Study No. S.0024589d 15, Human Cell Line Activation Test of the Novel Energetic, 3,4 -Dinitropyrazole (DNP)

    Science.gov (United States)

    2016-04-01

    Assay 1 0.259 0.278 Assay 2 0.299 6.3 CD54 and CD86 expression in response to DNP exposure of THP -1 cells Three independent tests were...2 Toxicology Study No. S.0024589d-15, April 2016 Toxicology Directorate Human Cell Line Activation Test of the Novel Energetic 3,4...report. 17-05-2016 Technical Report March 2016-April 2016 Toxicology Study No. S.0024589d-15 Human Cell Line Activation Test of the Novel

  7. A comparison of climatological subseasonal variations in the wintertime storm track activity between the North Pacific and Atlantic: local energetics and moisture effect

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sun-Seon; Ha, Kyung-Ja [Pusan National University, Division of Earth Environmental System, Busan (Korea, Republic of); Lee, June-Yi; Wang, Bin; Jin, Fei-Fei [University of Hawaii, School of Ocean and Earth Science and Technology, Honolulu, HI (United States); Lee, Woo-Jin [Korea Meteorological Administration, Seoul (Korea, Republic of)

    2011-12-15

    Distinct differences of the storm track-jet relationship over the North Pacific and North Atlantic are investigated in terms of barotropic and baroclinic energetics using NCEP-2 reanalysis data for the period of 1979-2008. From fall to midwinter the Pacific storm track (PST) activity weakens following the southward shift of the Pacific jet, whereas the Atlantic storm track (AST) activity remains steady in position and intensifies regardless of the slight southward shift of the Atlantic jet. This study is devoted to seeking for the factors that can contribute to this conspicuous difference between the two storm tracks on climatological subseasonal variation by analyzing eddy properties and local energetics. Different eddy properties over the two oceans lead to different contribution of barotropic energy conversion to the initiation of storm tracks. In the North Atlantic, meridionally elongated eddies gain kinetic energy efficiently from stretching deformation of the mean flow in the jet entrance. On the other hand, the term associated with shearing deformation is important for the initiation of PST. Analysis of baroclinic energetics reveals that the intensification of the AST activity in midwinter is mainly attributed to coincidence between location of maximum poleward and upward eddy heat fluxes and that of the largest meridional temperature gradient over slight upstream of the AST. The relatively large amount of precipitable water and meridional eddy moisture flux along baroclinic energy conversion axis likely provides a more favorable environment for baroclinic eddy growth over the North Atlantic than over the North Pacific. In the meantime, the midwinter minimum of the PST activity is attributable to the southward shift of the Pacific jet stream that leads to discrepancy between core region of poleward and upward heat fluxes and that of meridional thermal gradient. Weakening of eddy-mean flow interaction due to eddy shape and reduction of moist effect are also

  8. Human Cell Line Activation Test of the Novel Energetics Methyl Trinitropryrazol (MTNP) and 1,3-Dimethylhexahydropyrimidine (DHP)

    Science.gov (United States)

    2017-11-01

    costs, conserve physical resources, and sustain the health of those potentially exposed. The U.S. Army RDECOM, ETAP has been dedicated to finding...trinitropryrazol (MTNP) and 1,3-dimethylhexahydropyrimidine (DHP) Prepared by: Emily Reinke, Ph.D. Health Effects Division Toxicology...the Novel Energetics methyl trinitropyrazol (MTNP) and 1,3-dimethylhexahydropyrimidine (DHP) Emily N. Reinke, Ph.D. Army Public Health Center

  9. Solar energetic particle flux enhancement as a predictor of geomagnetic activity in a neural network-based model

    Czech Academy of Sciences Publication Activity Database

    Valach, F.; Revallo, M.; Bochníček, Josef; Hejda, Pavel

    2009-01-01

    Roč. 7, April (2009), S04004/1-S04004/7 ISSN 1542-7390 R&D Projects: GA AV ČR(CZ) IAA300120608; GA AV ČR 1QS300120506 Institutional research plan: CEZ:AV0Z30120515 Keywords : neural networks * coronal mass ejections * energetic particles * flares * radio emissions * magnetic storms Subject RIV: DE - Earth Magnetism, Geodesy, Geography Impact factor: 1.845, year: 2009

  10. Energetic Particles: From Sun to Heliosphere - and vice versa

    Science.gov (United States)

    Wimmer-Schweingruber, R. F.; Rodriguez-Pacheco, J.; Boden, S.; Boettcher, S. I.; Cernuda, I.; Dresing, N.; Drews, C.; Droege, W.; Espinosa Lara, F.; Gomez-Herrero, R.; Heber, B.; Ho, G. C.; Klassen, A.; Kulkarni, S. R.; Mann, G. J.; Martin-Garcia, C.; Mason, G. M.; Panitzsch, L.; Prieto, M.; Sanchez, S.; Terasa, C.; Eldrum, S.

    2017-12-01

    Energetic particles in the heliosphere can be measured at their elevated energetic status after three processes: injection, acceleration, and transport. Suprathermal seed particles have speeds well above the fast magnetosonic speed in the solar wind frame of reference and can vary from location to location and within the solar activity cycle. Acceleration sites include reconnecting current sheets in solar flares or magnetspheric boundaries, shocks in the solar corona, heliosphere and a planetary obstacles, as well as planetary magnetospheres. Once accelerated, particles are transported from the acceleration site into and through the heliosphere. Thus, by investigating properties of energetic particles such as their composition, energy spectra, pitch-angle distribution, etc. one can attempt to distinguish their origin or injection and acceleration site. This in turn allows us to better understand transport effects whose underlying microphysics is also a key ingredient in the acceleration of particles. In this presentation we will present some clear examples which link energetic particles from their observing site to their source locations. These include Jupiter electrons, singly-charged He ions from CIRs, and 3He from solar flares. We will compare these examples with the measurement capabilities of the Energetic Particle Detector (EPD) on Solar Orbiter and consider implications for the key science goal of Solar Orbiter and Solar Proble Plus - How the Sun creates and controls the heliosphere.

  11. Field-Lines-Threaded Model for: (1) the Low Solar Corona; (2) Electrons in the Transition Region; and (3) Solar Energetic Particle Acceleration and Transport

    Science.gov (United States)

    Sokolov, I.; van der Holst, B.; Jin, M.; Gombosi, T. I.; Taktakishvili, A.; Khazanov, G. V.

    2013-12-01

    In numerical simulations of the solar corona, both for the ambient state and especially for dynamical processes the most computational resources are spent for maintaining the numerical solution in the Low Solar Corona and in the transition region, where the temperature gradients are very sharp and the magnetic field has a complicated topology. The degraded computational efficiency is caused by the need in a highest resolution as well as the use of the fully three-dimensional implicit solver for electron heat conduction. On the other hand, the physical nature of the processes involved is rather simple (which still does not facilitate the numerical methods) as long as the heat fluxes as well as slow plasma motional velocities are aligned with the magnetic field. The Alfven wave turbulence, which is often believed to be the main driver of the solar wind and the main source of the coronal heating, is characterized by the Poynting flux of the waves, which is also aligned with the magnetic field. Therefore, the plasma state in any point of the three-dimensional grid in the Low Solar Corona can be found by solving a set of one-dimensional equations for the magnetic field line ('thread'), which passes through this point and connects it to the chromosphere and to the global Solar Corona. In the present paper we describe an innovative computational technology based upon the use of the magnetic-field-line-threads to find the local solution. We present the development of the AWSoM code of the University of Michigan with the field-lines-threaded Low Solar Corona. In the transition region, where the essentially kinetic description of the electron energy fluxes is required, we solve the Fokker-Plank equation on the system of threads, to achieve the physically consistent description of chromosphere evaporation. The third application for the field-lines-treaded model is the Solar Energetic Particle (SEP) acceleration and transport. Being the natural extension of the Field

  12. Musical Tasks and Energetic Arousal.

    Science.gov (United States)

    Lim, Hayoung A; Watson, Angela L

    2018-03-08

    Music is widely recognized as a motivating stimulus. Investigators have examined the use of music to improve a variety of motivation-related outcomes; however, these studies have focused primarily on passive music listening rather than active participation in musical activities. To examine the influence of participation in musical tasks and unique participant characteristics on energetic arousal. We used a one-way Welch's ANOVA to examine the influence of musical participation (i.e., a non-musical control and four different musical task conditions) upon energetic arousal. In addition, ancillary analyses of participant characteristics including personality, age, gender, sleep, musical training, caffeine, nicotine, and alcohol revealed their possible influence upon pretest and posttest energetic arousal scores. Musical participation yielded a significant relationship with energetic arousal, F(4, 55.62) = 44.38, p = .000, estimated ω2 = 0.60. Games-Howell post hoc pairwise comparisons revealed statistically significant differences between five conditions. Descriptive statistics revealed expected differences between introverts' and extraverts' energetic arousal scores at the pretest, F(1, 115) = 6.80, p = .010, partial η2= .06; however, mean differences failed to reach significance at the posttest following musical task participation. No other measured participant characteristics yielded meaningful results. Passive tasks (i.e., listening to a story or song) were related to decreased energetic arousal, while active musical tasks (i.e., singing, rhythm tapping, and keyboard playing) were related to increased energetic arousal. Musical task participation appeared to have a differential effect for individuals with certain personality traits (i.e., extroverts and introverts).

  13. The physical chemistry of coordinated aqua-, ammine-, and mixed-ligand Co2+ complexes: DFT studies on the structure, energetics, and topological properties of the electron density.

    Science.gov (United States)

    Varadwaj, Pradeep R; Marques, Helder M

    2010-03-07

    Spin-unrestricted DFT-X3LYP/6-311++G(d,p) calculations have been performed on a series of complexes of the form [Co(H(2)O)(6-n)(NH(3))(n)](2+) (n = 0-6) to examine their equilibrium gas-phase structures, energetics, and electronic properties in their quartet electronic ground states. In all cases Co(2+) in the energy-minimised structures is in a pseudo-octahedral environment. The calculations overestimate the Co-O and Co-N bond lengths by 0.04 and 0.08 A, respectively, compared to the crystallographically observed mean values. There is a very small Jahn-Teller distortion in the structure of [Co(H(2)O)(6)](2+) which is in contrast to the very marked distortions observed in most (but not all) structures of this cation that have been observed experimentally. The successive replacement of ligated H(2)O by NH(3) leads to an increase in complex stability by 6 +/- 1 kcal mol(-1) per additional NH(3) ligand. Calculations using UB3LYP give stabilisation energies of the complexes about 5 kcal mol(-1) smaller and metal-ligand bond lengths about 0.005 A longer than the X3LYP values since the X3LYP level accounts for the London dispersion energy contribution to the overall stabilisation energy whilst it is largely missing at the B3LYP level. From a natural population analysis (NPA) it is shown that the formation of these complexes is accompanied by ligand-to-metal charge transfer the extent of which increases with the number of NH(3) ligands in the coordination sphere of Co(2+). From an examination of the topological properties of the electron charge density using Bader's quantum theory of atoms in molecules it is shown that the electron density rho(c) at the Co-O bond critical points is generally smaller than that at the Co-N bond critical points. Hence Co-O bonds are weaker than Co-N bonds in these complexes and the stability increases as NH(3) replaces H(2)O in the metal's coordination sphere. Several indicators, including the sign and magnitude of the Laplacian of the

  14. Energetics Conditioning Facility

    Data.gov (United States)

    Federal Laboratory Consortium — The Energetics Conditioning Facility is used for long term and short term aging studies of energetic materials. The facility has 10 conditioning chambers of which 2...

  15. Active Pixel Sensors for electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Denes, P. [Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States)], E-mail: pdenes@lbl.gov; Bussat, J.-M. [Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Lee, Z.; Radmillovic, V. [National Center for Electron Microscopy, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States)

    2007-09-01

    The technology used for monolithic CMOS imagers, popular for cell phone cameras and other photographic applications, has been explored for charged particle tracking by the high-energy physics community for several years. This technology also lends itself to certain imaging detector applications in electron microscopy. We have been developing such detectors for several years at Lawrence Berkeley National Laboratory, and we and others have shown that this technology can offer excellent point-spread function, direct detection and high readout speed. In this paper, we describe some of the design constraints peculiar to electron microscopy and summarize where such detectors could play a useful role.

  16. Electron-beam-induced-current and active secondary-electron voltage-contrast with aberration-corrected electron probes

    Energy Technology Data Exchange (ETDEWEB)

    Han, Myung-Geun, E-mail: mghan@bnl.gov [Condensed Matter Physics & Materials Science, Brookhaven National Laboratory, Upton, NY 11973 (United States); Garlow, Joseph A. [Condensed Matter Physics & Materials Science, Brookhaven National Laboratory, Upton, NY 11973 (United States); Materials Science and Engineering Department, Stony Brook University, Stony Brook, NY 11794 (United States); Marshall, Matthew S.J.; Tiano, Amanda L. [Department of Chemistry, Stony Brook University, Stony Brook, NY 11974 (United States); Wong, Stanislaus S. [Condensed Matter Physics & Materials Science, Brookhaven National Laboratory, Upton, NY 11973 (United States); Department of Chemistry, Stony Brook University, Stony Brook, NY 11974 (United States); Cheong, Sang-Wook [Department of Physics and Astronomy, Rutgers Center for Emergent Materials, Rutgers University, Piscataway, NJ 08854 (United States); Walker, Frederick J.; Ahn, Charles H. [Department of Applied Physics and Center for Research on Interface Structures and Phenomena, Yale University, New Haven, CT 06520 (United States); Department of Mechanical Engineering and Materials Science, Yale University, New Haven, CT 06520 (United States); Zhu, Yimei [Condensed Matter Physics & Materials Science, Brookhaven National Laboratory, Upton, NY 11973 (United States)

    2017-05-15

    Highlights: • Electron-beam-induced-current (EBIC) and active secondary-electron voltage-contrast (SE-VC) are demonstrated in STEM mode combined with in situ electrical biasing in a TEM. • Electrostatic potential maps in ferroelectric thin films, multiferroic nanowires, and single crystals obtained by off-axis electron holography were compared with EBIC and SE-VC data. • Simultaneous EBIC and active SE-VC performed with atomic resolution STEM are demonstrated. - Abstract: The ability to map out electrostatic potentials in materials is critical for the development and the design of nanoscale electronic and spintronic devices in modern industry. Electron holography has been an important tool for revealing electric and magnetic field distributions in microelectronics and magnetic-based memory devices, however, its utility is hindered by several practical constraints, such as charging artifacts and limitations in sensitivity and in field of view. In this article, we report electron-beam-induced-current (EBIC) and secondary-electron voltage-contrast (SE-VC) with an aberration-corrected electron probe in a transmission electron microscope (TEM), as complementary techniques to electron holography, to measure electric fields and surface potentials, respectively. These two techniques were applied to ferroelectric thin films, multiferroic nanowires, and single crystals. Electrostatic potential maps obtained by off-axis electron holography were compared with EBIC and SE-VC to show that these techniques can be used as a complementary approach to validate quantitative results obtained from electron holography analysis.

  17. Electron Correlation Models for Optical Activity

    DEFF Research Database (Denmark)

    Höhn, E. G.; O. E. Weigang, Jr.

    1968-01-01

    A two-system no-overlap model for rotatory strength is developed for electric-dipole forbidden as well as allowed transitions. General equations which allow for full utilization of symmetry in the chromophore and in the environment are obtained. The electron correlation terms are developed in full...

  18. Location and dynamical peculiarities of auroral arcs during activations of different intensity

    International Nuclear Information System (INIS)

    Kozelova, T.V.; Pudovkin, M.I.; Kornilova, T.A.

    1991-01-01

    It is shown that the location of a flare arc with respect to the precipitation area of energetic electrons is one of substorm characteristics. Severe substorms begin with activization inside this area. The explosive phase of a weak substorm beginning outside the energetic electron precipitation area involves a series of activizations, in which every next activization mainly lies at the lower latitude

  19. Measurement of neutron energy spectra for Eg=23.1 and 26.6 MeV mono-energetic photon induced reaction on natC using laser electron photon beam at NewSUBARU

    Science.gov (United States)

    Itoga, Toshiro; Nakashima, Hiroshi; Sanami, Toshiya; Namito, Yoshihito; Kirihara, Yoichi; Miyamoto, Shuji; Takemoto, Akinori; Yamaguchi, Masashi; Asano, Yoshihiro

    2017-09-01

    Photo-neutron energy spectra for Eg=23.1 and 26.6 MeV mono-energetic photons on natC were measured using laser Compton scattering facility at NewSUBARU BL01. The photon energy spectra were evaluated through measurements and simulations with collimator sizes and arrangements for the laser electron photon. The neutron energy spectra for the natC(g,xn) reaction were measured at 60 degrees in horizontal and 90 degrees in horizontal and vertical with respect to incident photon. The spectra show almost isotropic angular distribution and flat energy distribution from detection threshold to upper limit defined by reaction Q-value.

  20. Computational study of the activity, dynamics, energetics and conformations of insulin analogues using molecular dynamics simulations: Application to hyperinsulinemia and the critical residue B26

    Directory of Open Access Journals (Sweden)

    Anastasios Papaioannou

    2017-09-01

    Full Text Available Due to the increasing prevalence of diabetes, finding therapeutic analogues for insulin has become an urgent issue. While many experimental studies have been performed towards this end, they have limited scope to examine all aspects of the effect of a mutation. Computational studies can help to overcome these limitations, however, relatively few studies that focus on insulin analogues have been performed to date. Here, we present a comprehensive computational study of insulin analogues—three mutant insulins that have been identified with hyperinsulinemia and three mutations on the critical B26 residue that exhibit similar binding affinity to the insulin receptor—using molecular dynamics simulations with the aim of predicting how mutations of insulin affect its activity, dynamics, energetics and conformations. The time evolution of the conformers is studied in long simulations. The probability density function and potential of mean force calculations are performed on each insulin analogue to unravel the effect of mutations on the dynamics and energetics of insulin activation. Our conformational study can decrypt the key features and molecular mechanisms that are responsible for an enhanced or reduced activity of an insulin analogue. We find two key results: 1 hyperinsulinemia may be due to the drastically reduced activity (and binding affinity of the mutant insulins. 2 Y26BS and Y26BE are promising therapeutic candidates for insulin as they are more active than WT-insulin. The analysis in this work can be readily applied to any set of mutations on insulin to guide development of more effective therapeutic analogues.

  1. Structural complexities in the active layers of organic electronics.

    Science.gov (United States)

    Lee, Stephanie S; Loo, Yueh-Lin

    2010-01-01

    The field of organic electronics has progressed rapidly in recent years. However, understanding the direct structure-function relationships between the morphology in electrically active layers and the performance of devices composed of these materials has proven difficult. The morphology of active layers in organic electronics is inherently complex, with heterogeneities existing across multiple length scales, from subnanometer to micron and millimeter range. A major challenge still facing the organic electronics community is understanding how the morphology across all of the length scales in active layers collectively determines the device performance of organic electronics. In this review we highlight experiments that have contributed to the elucidation of structure-function relationships in organic electronics and also point to areas in which knowledge of such relationships is still lacking. Such knowledge will lead to the ability to select active materials on the basis of their inherent properties for the fabrication of devices with prespecified characteristics.

  2. Nb and Ta layer doping effects on the interfacial energetics and electronic properties of LaAlO3/SrTiO3 heterostructure: first-principles analysis.

    Science.gov (United States)

    Nazir, Safdar; Behtash, Maziar; Cheng, Jianli; Luo, Jian; Yang, Kesong

    2016-01-28

    The two-dimensional electron gas (2DEG) formed at the n-type (LaO)(+1)/(TiO2)(0) interface in the polar/nonpolar LaAlO3/SrTiO3 (LAO/STO) heterostructure (HS) has emerged as a prominent research area because of its great potential for nanoelectronic applications. Due to its practical implementation in devices, desired physical properties such as high charge carrier density and mobility are vital. In this respect, 4d and 5d transition metal doping near the interfacial region is expected to tailor electronic properties of the LAO/STO HS system effectively. Herein, we studied Nb and Ta-doping effects on the energetics, electronic structure, interfacial charge carrier density, magnetic moment, and the charge confinements of the 2DEG at the n-type (LaO)(+1)/(TiO2)(0) interface of LAO/STO HS using first-principles density functional theory calculations. We found that the substitutional doping of Nb(Ta) at Ti [Nb(Ta)@Ti] and Al [Nb(Ta)@Al] sites is energetically more favorable than that at La [Nb(Ta)@La] and Sr [Nb(Ta)@Sr] sites, and under appropriate thermodynamic conditions, the changes in the interfacial energy of HS systems upon Nb(Ta)@Ti and Nb(Ta)@Al doping are negative, implying that the formation of these structures is energetically favored. Our calculations also showed that Nb(Ta)@Ti and Nb(Ta)@Al doping significantly improve the interfacial charge carrier density with respect to that of the undoped system, which is because the Nb(Ta) dopant introduces excess free electrons into the system, and these free electrons reside mainly on the Nb(Ta) ions and interfacial Ti ions. Hence, along with the Ti 3d orbitals, the Nb 4d and Ta 5d orbitals also contribute to the interfacial metallic states; accordingly, the magnetic moments on the interfacial Ti ions increase significantly. As expected, the Nb@Al and Ta@Al doped LAO/STO HS systems show higher interfacial charge carrier density than the undoped and other doped systems. In contrast, Nb@Ti and Ta@Ti doped systems may

  3. Source Characterization Model (SCM): A Predictive Capability for the Source Terms of Residual Energetic Materials from Burning and/or Detonation Activities

    National Research Council Canada - National Science Library

    Brown, Robert C; Kolb, Charles E; Conant, John A; Zhang, John; Dussault, David M; Rush, Tamera L; Conway, Brooke E; Morris, James W; Touma, Joe

    2004-01-01

    .... Detonation of energetic materials produces a wide range of air and surface pollutants, including carbon monoxide, nitrogen oxides, volatile organic compounds, acid gases, and particulate matter...

  4. Quality control of the documentation process in electronic economic activities

    Directory of Open Access Journals (Sweden)

    Krutova A.S.

    2017-06-01

    Full Text Available It is proved that the main tool that will provide adequate information resources e economic activities of social and economic relations are documenting quality control processes as the basis of global information space. Directions problems as formation evaluation information resources in the process of documentation, namely development tools assess the efficiency of the system components – qualitative assessment; development of mathematical modeling tools – quantitative evaluation. A qualitative assessment of electronic documentation of economic activity through exercise performance, efficiency of communication; document management efficiency; effectiveness of flow control operations; relationship management effectiveness. The concept of quality control process documents electronically economic activity to components which include: the level of workflow; forms adequacy of information; consumer quality documents; quality attributes; type of income data; condition monitoring systems; organizational level process documentation; attributes of quality, performance quality consumer; type of management system; type of income data; condition monitoring systems. Grounded components of the control system electronic document subjects of economic activity. Detected components IT-audit management system economic activity: compliance audit; audit of internal control; detailed multilevel analysis; corporate risk assessment methodology. The stages and methods of processing electronic transactions economic activity during condition monitoring of electronic economic activity.

  5. 76 FR 9024 - Agency Information Collection Activities; Proposed Collection; Comment Request; Electronic...

    Science.gov (United States)

    2011-02-16

    ...] Agency Information Collection Activities; Proposed Collection; Comment Request; Electronic Records; Electronic Signatures AGENCY: Food and Drug Administration, HHS. ACTION: Notice. SUMMARY: The Food and Drug... relating to FDA's electronic records and electronic signatures. DATES: Submit either electronic or written...

  6. Energetic charged particles above thunderclouds

    International Nuclear Information System (INIS)

    Fullekrug, Martin; Diver, Declan; Pincon, Jean-Louis; Renard, Jean-Baptiste; Phelps, Alan D.R.; Bourdon, Anne; Helling, Christiane; Blanc, Elisabeth; Honary, Farideh; Kosch, Mike; Harrison, Giles; Sauvaud, Jean-Andre; Lester, Mark; Rycroft, Michael; Kosch, Mike; Horne, Richard B.; Soula, Serge; Gaffet, Stephane

    2013-01-01

    The French government has committed to launch the satellite TARANIS to study transient coupling processes between the Earth's atmosphere and near-Earth space. The prime objective of TARANIS is to detect energetic charged particles and hard radiation emanating from thunderclouds. The British Nobel prize winner C. T. R. Wilson predicted lightning discharges from the top of thunderclouds into space almost a century ago. However, new experiments have only recently confirmed energetic discharge processes which transfer energy from the top of thunderclouds into the upper atmosphere and near-Earth space; they are now denoted as transient luminous events, terrestrial gamma-ray flashes and relativistic electron beams. This meeting report builds on the current state of scientific knowledge on the physics of plasmas in the laboratory and naturally occurring plasmas in the Earth's atmosphere to propose areas of future research. The report specifically reflects presentations delivered by the members of a novel Franco-British collaboration during a meeting at the French Embassy in London held in November 2011. The scientific subjects of the report tackle ionization processes leading to electrical discharge processes, observations of transient luminous events, electromagnetic emissions, energetic charged particles and their impact on the Earth's atmosphere. The importance of future research in this area for science and society, and towards spacecraft protection, is emphasized. (authors)

  7. Pilot experiment on utilization of vegetable biomass in Umbria. Part 2. Anaerobic digestion of the wastes coming from the maintenance activity of the lake Trasimeno and the working of energetic cultures

    International Nuclear Information System (INIS)

    Poletti, A.; Selvaggi, R.; Poletti, L.

    2000-01-01

    In this work the energetic exploitation has been assessed of the vegetable biomasses available in the region Umbria, derived both from the maintenance operation of Lake Trasimeno and energetic cultures. Biomethanation experiments have been carried out both on laboratory scale, by preparing anaerobic digestion tests in batch and in continuous, and on pilot scale, through the use of a 2000 litres digest or. Throughout the experiment the main chemical and physical process parameters have been monitored and the process efficiency assessed. The experimental values, measured for the anaerobic digestion process, have shown that both types of biomass can be very good substrated for the production of biogas. Their energetic re-use, when considering the broad and complex problems posed by breeding wastes disposal, could positively contribute to a rational sustainability scheme of the activities operating in the territory [it

  8. Structural energetics of noble metals

    International Nuclear Information System (INIS)

    Mujibur Rahman, S.M.

    1982-06-01

    Structural energetics of the noble metals, namely Cu, Ag, and Au are investigated by employing a single-parameter pseudopotential. The calculations show that the lowest energy for all of these metals corresponds to FCC - their observed crystal structure. The one-electron contribution to the free energy is found to dominate the structural prediction for these metals. The present investigation strongly emphasizes that the effects due to band hybridization and core-core exchange play a significant role on the structural stability of the noble metals. (author)

  9. Large enhancement of highly energetic electrons in the outer radiation belt and its transport into the inner radiation belt inferred from MDS-1 satellite observations

    Science.gov (United States)

    Obara, T.; Matsumoto, H.

    2016-03-01

    We have examined a large increase of relativistic electrons in the outer radiation belt and its penetration into the inner radiation belt over slot region using the MDS-1 satellite observations. Result of analyses demonstrates that a large increase took place in the spring and autumn seasons, and we have newly confirmed that the penetration of outer belt electrons to the inner radiation zone took place during the big magnetic storms by examining a pitch angle distribution of the penetrating electrons.

  10. A constitutively activating mutation alters the dynamics and energetics of a key conformational change in a ligand-free G protein-coupled receptor.

    Science.gov (United States)

    Tsukamoto, Hisao; Farrens, David L

    2013-09-27

    G protein-coupled receptors (GPCRs) undergo dynamic transitions between active and inactive conformations. Usually, these conversions are triggered when the receptor detects an external signal, but some so-called constitutively activating mutations, or CAMs, induce a GPCR to bind and activate G proteins in the absence of external stimulation, in ways still not fully understood. Here, we investigated how a CAM alters the structure of a GPCR and the dynamics involved as the receptor transitions between different conformations. Our approach used site-directed fluorescence labeling (SDFL) spectroscopy to compare opsin, the ligand-free form of the GPCR rhodopsin, with opsin containing the CAM M257Y, focusing specifically on key movements that occur in the sixth transmembrane helix (TM6) during GPCR activation. The site-directed fluorescence labeling data indicate opsin is constrained to an inactive conformation both in detergent micelles and lipid membranes, but when it contains the M257Y CAM, opsin is more dynamic and can interact with a G protein mimetic. Further study of these receptors using tryptophan-induced quenching (TrIQ) methods indicates that in detergent, the CAM significantly increases the population of receptors in the active state, but not in lipids. Subsequent Arrhenius analysis of the TrIQ data suggests that, both in detergent and lipids, the CAM lowers the energy barrier for TM6 movement, a key transition required for conversion between the inactive and active conformations. Together, these data suggest that the lowered energy barrier is a primary effect of the CAM on the receptor dynamics and energetics.

  11. Energetic certification in Europe

    International Nuclear Information System (INIS)

    1998-01-01

    At community level the problem of energy quality control in a building was introduced by EEC recommendation n. 93/76 in 1993. In this item are reported some notes on energetic certification in European countries [it

  12. Energetics Laboratory Facilities

    Data.gov (United States)

    Federal Laboratory Consortium — These energetic materials laboratories are equipped with explosion proof hoods with blow out walls for added safety, that are certified for safe handling of primary...

  13. Measurement of neutron energy spectra for Eg=23.1 and 26.6 MeV mono-energetic photon induced reaction on natC using laser electron photon beam at NewSUBARU

    Directory of Open Access Journals (Sweden)

    Itoga Toshiro

    2017-01-01

    Full Text Available Photo-neutron energy spectra for Eg=23.1 and 26.6 MeV mono-energetic photons on natC were measured using laser Compton scattering facility at NewSUBARU BL01. The photon energy spectra were evaluated through measurements and simulations with collimator sizes and arrangements for the laser electron photon. The neutron energy spectra for the natC(g,xn reaction were measured at 60 degrees in horizontal and 90 degrees in horizontal and vertical with respect to incident photon. The spectra show almost isotropic angular distribution and flat energy distribution from detection threshold to upper limit defined by reaction Q-value.

  14. Patient activation and use of an electronic patient portal.

    Science.gov (United States)

    Ancker, Jessica S; Osorio, Snezana N; Cheriff, Adam; Cole, Curtis L; Silver, Michael; Kaushal, Rainu

    2015-01-01

    Electronic patient portals give patients access to personal medical data, potentially creating opportunities to improve knowledge, self-efficacy, and engagement in healthcare. The combination of knowledge, self-efficacy, and engagement has been termed activation. Our objective was to assess the relationship between patient activation and outpatient use of a patient portal. Survey. A telephone survey was conducted with 180 patients who had been given access to a portal, 113 of whom used it and 67 of whom did not. The validated patient activation measure (PAM) was administered along with questions about demographics and behaviors. Portal users were no different from nonusers in patient activation. Portal users did have higher education level and more frequent Internet use, and were more likely to have precisely 2 prescription medications than to have more or fewer. Patients who chose to use an electronic patient portal were not more highly activated than nonusers, although they were more educated and more likely to be Internet users.

  15. Activity coefficients of electrons and holes in semiconductors

    International Nuclear Information System (INIS)

    Orazem, M.E.; Newman, J.

    1984-01-01

    Dilute-solution transport equations with constant activity coefficients are commonly used to model semiconductors. These equations are consistent with a Boltzmann distribution and are invalid in regions where the species concentration is close to the respective site concentration. A more rigorous treatment of transport in a semiconductor requires activity coefficients which are functions of concentration. Expressions are presented for activity coefficients of electrons and holes in semiconductors for which conduction- and valence-band energy levels are given by the respective bandedge energy levels. These activity coefficients are functions of concentration and are thermodynamically consistent. The use of activity coefficients in macroscopic transport relationships allows a description of electron transport in a manner consistent with the Fermi-Dirac distribution

  16. Safer energetic materials by a nanotechnological approach

    Science.gov (United States)

    Siegert, Benny; Comet, Marc; Spitzer, Denis

    2011-09-01

    Energetic materials - explosives, thermites, populsive powders - are used in a variety of military and civilian applications. Their mechanical and electrostatic sensitivity is high in many cases, which can lead to accidents during handling and transport. These considerations limit the practical use of some energetic materials despite their good performance. For industrial applications, safety is one of the main criteria for selecting energetic materials. The sensitivity has been regarded as an intrinsic property of a substance for a long time. However, in recent years, several approaches to lower the sensitivity of a given substance, using nanotechnology and materials engineering, have been described. This feature article gives an overview over ways to prepare energetic (nano-)materials with a lower sensitivity.Energetic materials - explosives, thermites, populsive powders - are used in a variety of military and civilian applications. Their mechanical and electrostatic sensitivity is high in many cases, which can lead to accidents during handling and transport. These considerations limit the practical use of some energetic materials despite their good performance. For industrial applications, safety is one of the main criteria for selecting energetic materials. The sensitivity has been regarded as an intrinsic property of a substance for a long time. However, in recent years, several approaches to lower the sensitivity of a given substance, using nanotechnology and materials engineering, have been described. This feature article gives an overview over ways to prepare energetic (nano-)materials with a lower sensitivity. Electronic supplementary information (ESI) available: Experimental details for the preparation of the V2O5@CNF/Al nanothermite; X-ray diffractogram of the V2O5@CNF/Al combustion residue; installation instructions and source code for the nt-timeline program. See DOI: 10.1039/c1nr10292c

  17. Energetic solar particles

    International Nuclear Information System (INIS)

    Biswas, M.

    1975-01-01

    In this review, some of the important aspects of energetic solar particles and their relation to solar physics are discussed. The major aspects of solar cosmic ray studies currently under investigation are identified and attention is focussed on the problems of the physical processes in the sun which may be responsible for these phenomena. The studies of the composition and energy spectra of solar cosmic ray nuclei are related to the basic problem of particle acceleration process in sun and to the composition of elements in solar atmosphere. The composition of higher energy (>20 MeV/amu) multiply charged nuclei of He, C, N, O, Ne, Mg, Si and Fe give information on the abundance of elements in the solar atmosphere. At lower energies (approximately 1-10 MeV/amu), the abundances of these elements show enhancements relative to solar abundances and these enhancements are believed to be due to particle acceleration mechanisms operative in the sun which are not fully understood at present. Studies of the relative abundances of H 2 , H 3 and He 3 isotopes and Li, Be, B nuclei in the solar cosmic rays can also be studied. The question of the relationship of the accelerated particles in the sun to the optical flare phenomena is discussed. Further studies of different aspects of these phenomena may give important clues to a wide ranging phenomena in the active sun. The observational methods employed for these studies are mentioned. (A.K.)

  18. The energetic state of mitochondria modulates complex III biogenesis through the ATP-dependent activity of Bcs1.

    Science.gov (United States)

    Ostojić, Jelena; Panozzo, Cristina; Lasserre, Jean-Paul; Nouet, Cécile; Courtin, Florence; Blancard, Corinne; di Rago, Jean-Paul; Dujardin, Geneviève

    2013-10-01

    Our understanding of the mechanisms involved in mitochondrial biogenesis has continuously expanded during the last decades, yet little is known about how they are modulated to optimize the functioning of mitochondria. Here, we show that mutations in the ATP binding domain of Bcs1, a chaperone involved in the assembly of complex III, can be rescued by mutations that decrease the ATP hydrolytic activity of the ATP synthase. Our results reveal a Bcs1-mediated control loop in which the biogenesis of complex III is modulated by the energy-transducing activity of mitochondria. Although ATP is well known as a regulator of a number of cellular activities, we show here that ATP can be also used to modulate the biogenesis of an enzyme by controlling a specific chaperone involved in its assembly. Our study further highlights the intramitochondrial adenine nucleotide pool as a potential target for the treatment of Bcs1-based disorders. Copyright © 2013 Elsevier Inc. All rights reserved.

  19. Emission of low-energetic electrons in collisions of heavy ions with solid targets; Emission niederenergetischer Elektronen in Stoessen von schweren Ionen mit Festkoerpertargets

    Energy Technology Data Exchange (ETDEWEB)

    Lineva, Natallia

    2008-07-15

    At the UNILAC accelerator, we have initiated a project with the objective to investigate lowenergy electrons, emitted from solid, electrically conductive targets after the impact of swift light and heavy ions. For this purposes, we have installed, optimized, and put into operation an electrostatic toroidal electron spectrometer. First, investigations of electrons, emitted from solid-state targets after the bombardment with a monochromatic electron beam from an electron gun, has been carried out. The proposed method combines the results of the measurements with the results of dedicated Monte Carlo simulations. The method has been elaborated in a case study for carbon targets. The findings have been instrumental for the interpretation of our measurements of electrons emitted in collisions of swift ions with the same carbon targets. Our investigations focused on following ion beams: protons and (H{sup +}{sub 3})-molecules of the same energy, as well as on carbon ions with two different energies. Thin carbon, nickel, argon and gold foils has been used as targets. Electrons in the energy range between 50 eV and 1 keV have been investigated. The measured electron distributions, both integral as well as differential with respect to the polar angle, have been compared to simple standard theories for gases as well as to the results of TRAX simulations, the latter being based on data from gaseous targets. Dedicated TRAX simulations have been performed only for the carbon targets, applying the method mentioned above. Within our experimental uncertainties, we observe a good agreement of the measured and TRAX simulated data. That leads us to the conclusion that - as a first order approximation - the electron emission pattern from ion-atom collisions in solid-state targets and the one from single collisions in gases are similar. (orig.)

  20. Segregation and redistribution of end-of-process energetic materials

    International Nuclear Information System (INIS)

    McCabe, R.A.; Cummins, B.; Gonzalez, M.A.

    1993-03-01

    A system recovering then recycling or reusing end-of-process energetic materials has been developed at the Lawrence Livermore National Laboratory (LLNL). The system promotes separating energetic materials with high potential for reuse or recycling from those that have no further value. A feature of the system is a computerized electronic bulletin board for advertising the availability of surplus and recovered energetic materials and process chemicals to LLNL researchers, and for posting energetic materials, ''want ads.'' The system was developed and implemented to promote waste minimization and pollution prevention at LLNL

  1. Electron beam injection during active experiments. I - Electromagnetic wave emissions

    Science.gov (United States)

    Winglee, R. M.; Kellogg, P. J.

    1990-01-01

    The wave emissions produced in Echo 7 experiment by active injections of electron beams were investigated to determine the properties of the electromagnetic and electrostatic fields for both the field-aligned and cross-field injection in such experiments and to evaluate the sources of free energy and relative efficiencies for the generation of the VLF and HF emissions. It is shown that, for typical beam energies in active experiments, electromagnetic effects do not substantially change the bulk properties of the beam, spacecraft charging, and plasma particle acceleration. Through simulations, beam-generated whistlers; fundamental z-mode and harmonic x-mode radiation; and electrostatic electron-cyclotron, upper-hybrid, Langmuir, and lower-hybrid waves were identified. The characteristics of the observed wave spectra were found to be sensitive to both the ratio of the electron plasma frequency to the cyclotron frequency and the angle of injection relative to the magnetic field.

  2. Soft Active Materials for Actuation, Sensing, and Electronics

    OpenAIRE

    Kramer, Rebecca Krone

    2012-01-01

    Future generations of robots, electronics, and assistive medical devices will include systems that are soft and elastically deformable, allowing them to adapt their morphology in unstructured environments. This will require soft active materials for actuation, circuitry, and sensing of deformation and contact pressure. The emerging field of soft robotics utilizes these soft active materials to mimic the inherent compliance of natural soft-bodied systems. As the elasticity of robot components ...

  3. Protecting patients’ electronic health records using enhanced active bundles

    NARCIS (Netherlands)

    Salih, R.M.; Lilien, L.T.; Ben Othmane, L.; Arriaga, R.; Matic, A.

    2012-01-01

    We propose a solution that provides protection for patients' electronic health/medical records disseminated among different authorized healthcare information systems. The solution is known as Active Bundles using a Trusted Third Party (ABTTP). It is based on the use of trusted third parties, and the

  4. Regeneration of used activated carbon by electron beam irradiation

    International Nuclear Information System (INIS)

    Arai, H.; Hosono, M.; Zhu, G.; Miyata, T.

    1992-01-01

    The adsorbing power of granular activated carbons which adsorbed sodium laurylsulfate were most effectively recovered by irradiation of high energy electron beams in nitrogen stream, and the carbon was hardly lost by irradiation. The regeneration was induced mainly by microscopic heating of adsorption sites. Regeneration was also confirmed by adsorption endotherms. Regeneration cost was tentatively evaluated. (author)

  5. A unified view of energetic efficiency in active drag reduction, thrust generation and self-propulsion through a loss coefficient with some applications

    Science.gov (United States)

    Arakeri, Jaywant H.; Shukla, Ratnesh K.

    2013-08-01

    An analysis of the energy budget for the general case of a body translating in a stationary fluid under the action of an external force is used to define a power loss coefficient. This universal definition of power loss coefficient gives a measure of the energy lost in the wake of the translating body and, in general, is applicable to a variety of flow configurations including active drag reduction, self-propulsion and thrust generation. The utility of the power loss coefficient is demonstrated on a model bluff body flow problem concerning a two-dimensional elliptical cylinder in a uniform cross-flow. The upper and lower boundaries of the elliptic cylinder undergo continuous motion due to a prescribed reflectionally symmetric constant tangential surface velocity. It is shown that a decrease in drag resulting from an increase in the strength of tangential surface velocity leads to an initial reduction and eventual rise in the power loss coefficient. A maximum in energetic efficiency is attained for a drag reducing tangential surface velocity which minimizes the power loss coefficient. The effect of the tangential surface velocity on drag reduction and self-propulsion of both bluff and streamlined bodies is explored through a variation in the thickness ratio (ratio of the minor and major axes) of the elliptical cylinders.

  6. Resonance zones and quasi-linear diffusion coefficients for radiation belt energetic electron interaction with oblique chorus waves in the Dungey magnetosphere

    International Nuclear Information System (INIS)

    Shi Run; Ni, Binbin; Gu Xudong; Zhao Zhengyu; Zhou Chen

    2012-01-01

    The resonance regions for resonant interactions of radiation belt electrons with obliquely propagating whistler-mode chorus waves are investigated in detail in the Dungey magnetic fields that are parameterized by the intensity of uniform southward interplanetary magnetic field (IMF) Bz or, equivalently, by the values of D=(M/B z,0 ) 1/3 (where M is the magnetic moment of the dipole and B z,0 is the uniform southward IMF normal to the dipole’s equatorial plane). Adoption of background magnetic field model can considerably modify the determination of resonance regions. Compared to the results for the case of D = 50 (very close to the dipole field), the latitudinal coverage of resonance regions for 200 keV electrons interacting with chorus waves tends to become narrower for smaller D-values, regardless of equatorial pitch angle, resonance harmonics, and wave normal angle. In contrast, resonance regions for 1 MeV electrons tend to have very similar spatial lengths along the field line for various Dungey magnetic field models but cover different magnetic field intervals, indicative of a strong dependence on electron energy. For any given magnetic field line, the resonance regions where chorus-electron resonant interactions can take place rely closely on equatorial pitch angle, resonance harmonics, and kinetic energy. The resonance regions tend to cover broader latitudinal ranges for smaller equatorial pitch angles, higher resonance harmonics, and lower electron energies, consistent with the results in Ni and Summers [Phys. Plasmas 17, 042902, 042903 (2010)]. Calculations of quasi-linear bounce-averaged diffusion coefficients for radiation belt electrons due to nightside chorus waves indicate that the resultant scattering rates differ from using different Dungey magnetic field models, demonstrating a strong dependence of wave-induced electron scattering effect on the adoption of magnetic field model. Our results suggest that resonant wave-particle interaction processes

  7. Nighttime ionization by energetic particles at Wallops Island in the altitude region 120 to 200 km

    International Nuclear Information System (INIS)

    Voss, H.D.; Smith, L.G.

    1979-01-01

    Five Nike Apache rockets, each including an energetic particle spectrometer and an electron density-electron temperature experiment, have been launched from Wallops Island (L=2.6) near midnight under varying geomagnetic conditions. On the most recent of these (5 January 1978) an additional spectrometer with a broom magnet, and a 391.4 nm photometer were flown. The data from this flight indicate that the energetic particle flux consists predominantly of protons, neutral hydrogen and possibly other energetic nuclei. The energy spectrum becomes much softer and the flux more intense with increasing Kp for 10 0 indicating that the majority of particles are near their mirroring altitude. Ionization rates are calculated based on the measured energy spectrum and mirror height distribution. The resulting ionization rate profile is found to be nearly constant with altitude in the region 120 to 200 km. The measured energetic particle flux and calculated ionization rate from the five flights are found to vary with magnetic activity (based on the Kp and Dst indexes) in the same way as the independently derived ionization rates deduced from the electron density profile

  8. Nighttime ionization by energetic particles at Wallops Island in the altitude region 120 to 200 km

    Science.gov (United States)

    Voss, H. D.; Smith, L. G.

    1979-01-01

    Five Nike Apache rockets, each including an energetic particle spectrometer and an electron density-electron temperature experiment, have been launched from Wallops Island (L = 2.6) near midnight under varying geomagnetic conditions. On the most recent of these (5 January 1978) an additional spectrometer with a broom magnet, and a 391.4 nm photometer were flown. The data from this flight indicate that the energetic particle flux consists predominantly of protons, neutral hydrogen and possibly other energetic nuclei. The energy spectrum becomes much softer and the flux more intense with increasing Kp for 10-100 keV. The pitch angle distribution at 180 km is asymmetrical with a peak at 90 deg indicating that the majority of particles are near their mirroring altitude. Ionization rates are calculated based on the measured energy spectrum and mirror height distribution. The resulting ionization rate profile is found to be nearly constant with altitude in the region 120 to 200 km. The measured energetic particle flux and calculated ionization rate from the five flights are found to vary with magnetic activity (based on the Kp and Dst indexes) in the same way as the independently derived ionization rates deduced from the electron density profile.

  9. 15-year-activity of Electron Linear Accelerator Laboratory

    International Nuclear Information System (INIS)

    Karolczak, S.

    1999-01-01

    The purchase of the Russian Electron Linear Accelerator ELU-6E by Institute of Radiation Technique of Lodz Technical University in 1978 started the activity of the ELA Laboratory. The accelerator itself and many additional scientific equipment designed and built during past 15 years have became the basic investigation tool for the ITR now. The most important measuring systems based on electron beam as irradiation source are: pulse radiolysis system with detection in IR, UV and visible region of the spectra, radiation induced conductometry, Faraday chamber and computerized data acquisition and processing system

  10. The relationship between ionospheric temperature, electron density and solar activity

    International Nuclear Information System (INIS)

    McDonald, J.N.; Williams, P.J.S.

    1980-01-01

    In studying the F-region of the ionosphere several authors have concluded that the difference between the electron temperature Tsub(e) and the ion temperature Tsub(i) is related to the electron density N. It was later noted that solar activity (S) was involved and an empirical relationship of the following form was established: Tsub(e)-Tsub(i) = A-BN+CS. The present paper extends this work using day-time data over a four year period. The results are given and discussed. A modified form of the empirical relation is proposed. (U.K.)

  11. Agricultural management legacy affects microbial energetics, resource utilization and active bacterial community membership during 13C-glucose consumption

    Science.gov (United States)

    Helgason, B. L.; Levy-Booth, D.; Arcand, M. M.

    2017-12-01

    Over the long-term, differences in soil management can result in fundamental changes in biogeochemical cycling. The Alternative Cropping Systems (ACS) Study at Scott, SK, Canada (est. 1994) compares organic (ORG) vs. conventionally (CON) managed crop rotations in a loamy Typic Borall. Nitrogen (N) and phosphorus (P) deficiency in the ORG systems have limited crop growth and thus plant carbon (C) inputs for over two decades, ultimately resulting in a C deficiency which has further altered biogeochemical cycling. We conducted a short-term microcosm experiment using 13C-glucose stable isotope probing (SIP) of DNA to test whether ORG soils have greater microbial C use efficiency due to long term resource limitation. Glucose-utilizing populations were dominated by Proteobacteria and Actinobacteria, with differing species-level identities and physiological capacities between CON and ORG systems. Of the 13C-utilizing taxa, relative abundance of Proteobacteria was greater in CON while Actinobacteria (and notably Firmicutes) were more dominant in ORG soils. Using isothermal calorimetry, we measured a thermodynamic efficiency (ηeff) of 0.68, which was not significantly different between soils indicating that the metabolic cost of glucose utilization was similar in CON and ORG soils. In spite of this, differential abundance analysis of 13C-labelled OTUs revealed that ORG soils had distinct active bacterial populations that were positively correlated with ηeff, ηsoil (glucose energy retained in soil) and primed soil organic matter (pSOM). In contrast, differentially abundant OTUs in the CON soils were negatively correlated with measures of thermodynamic efficiency but positively correlated with glucose-derived heat and CO2 production as well as NO3- and PO4- availability. ORG bacterial communities may co-metabolize other resources (N and P) from SOM to meet their metabolic requirements during glucose utilization, while the active bacteria in the CON soils could access these

  12. Photoactive energetic materials

    Science.gov (United States)

    Chavez, David E.; Hanson, Susan Kloek; Scharff, Robert Jason; Veauthier, Jacqueline Marie; Myers, Thomas Winfield

    2018-02-27

    Energetic materials that are photoactive or believed to be photoactive may include a conventional explosive (e.g. PETN, nitroglycerine) derivatized with an energetic UV-absorbing and/or VIS-absorbing chromophore such as 1,2,4,5-tetrazine or 1,3,5-triazine. Absorption of laser light having a suitably chosen wavelength may result in photodissociation, decomposition, and explosive release of energy. These materials may be used as ligands to form complexes. Coordination compounds include such complexes with counterions. Some having the formula M(L).sub.n.sup.2+ were synthesized, wherein M is a transition metal and L is a ligand and n is 2 or 3. These may be photoactive upon exposure to a laser light beam having an appropriate wavelength of UV light, near-IR and/or visible light. Photoactive materials also include coordination compounds bearing non-energetic ligands; in this case, the counterion may be an oxidant such as perchlorate.

  13. Theoretical and experimental investigations of the damage and activation of pure iron under irradiation with energetic light ions

    International Nuclear Information System (INIS)

    Daum, E.

    1996-10-01

    In this report the applicability of light ion simulation irradiations with respect to the displacement damage under fusion neutron irradiation is investigated by theoretical and experimental activities. The production of primary knock-on atoms (PKA) and the displacement of lattice atoms (DPA) under proton and α-particle irradiation is considered in pure iron. The main focus is put on the effect of the non-elastic processes which are characterized by nuclear reactions and taken into account quantitatively for the first time. The profiles of the non-elastic PKA spectra can be characterized by the excitation functions of the corresponding nuclear reactions and by the mean recoil ranges of the residue nuclides. In this framework the excitation functions of proton- and α-particle-induced nuclear reactions leading to the long-lived nuclides from 57 Ni to 47 Sc are measured. The short-lived nuclides 53 Fe g , 53 Fe m , 52 Mn m and 52 V are investigated for the first time. The mean recoil ranges of the non-elastic PKA are experimentally determined by the same method. Based on theoretical calculations with nuclear and range models, non-elastic PKA spectra are obtained for all open reaction channels. (orig./WL)

  14. Study of energetic electrons in the outer radiation-belt regions using data obtained by the LLL spectrometer on OGO-5 in 1968

    International Nuclear Information System (INIS)

    West, H.I. Jr.; Buck, R.M.; Davidson, G.

    1979-01-01

    An account is given of measurements of electrons made by the LLL magnetic electron spectrometer (60 to 3000 keV in seven differential energy channels) on the Ogo-5 satellite in the earth's outer-belt regions during 1968 and early 1969. The data were analyzed specifically to determine pitch-angle diffusion lifetimes as a function of energy in the L-range 2 to 5. As a part of this effort, the general dynamics of these regions were studied in terms of the time-dependent energy spectra, and pitch-angle distributions for the seven energy groups were obtained as a function of L with representative values presented for L = 2.5 to 6. The pitch-angle-diffusion results were used to analyze the dynamics of the electrons injected following the intense storms on October 31 and November 1, 1968, in terms of radial diffusion; the derived diffusion coefficients provide a quite reasonable picture of electron transport in the radiation belts. Both the radial- and pitch-angle-diffusion results are compared with earlier results. 53 references

  15. Radiational and energetic characteristics of diatomic molecules (data base)

    International Nuclear Information System (INIS)

    Kuznetsova, L.A.; Pazyuk, E.A.; Stolyarov, A.V.

    1993-01-01

    Data base on radiational and energetic characteristics of diatomic molecules was created. The base consists of two parts: reference system and recommended data system. The reference system contains the information about studies of radiational and energetic parameters of more than 1500 electronic states and 1700 electron transfers for ∼ 350 diatomic molecules and their ions. The base bibliography includes ∼ 3000 publications. 11 refs., 1 figs

  16. High-resolution energetic particle measurements at 6.6R/sub E/ 3. Low-energy electron anisotropies and short-term substorm predictions

    International Nuclear Information System (INIS)

    Baker, D.N.; Higbie, P.R.; Hones, E.W. Jr.; Belian, R.D.

    1978-01-01

    Multiple detectors giving nearly complete 4π coverage of particle pitch angle distributions have provided high resolution measurements (in energy and time) of 30- to 300-keV electrons. Data from a spacecraft (1976-059A) in geostationary orbit show a remarkably consistent sequence of variations of the electron anisotropy before and during magnetospheric substorms. For periods typically 1--2 hours prior to the onset of substorms, electron distributions, peaked along the direction of the local magnetic field, are observed in the premidnight sector. These cigarlike anisotropies are accompanied by a local taillike magnetic field which may develop further during the event. At substorm onset an abrupt transition usually occurs from the cigar-shaped distributions to pancake-shaped distributions. This anisotropy sequence may be due to the buildup and subsequent release of stresses in the magnetotail; the cigar phase may also be due to associated processes at the dayside magnetopause causing a loss of 90 0 pitch angle particles. The present observations, based on approx.100 events, appear to provide a predictive tool for assessing the probability of occurrence of a substorm

  17. Markets, jobs, and energetic challenge of activities related to renewable energies and to energy efficiency. Situation in 2007-2008. Perspectives for 2009

    International Nuclear Information System (INIS)

    2009-10-01

    This study proposes an annual evolution survey of markets and jobs related to the development of renewable energies and to the improvement of energy efficiency in the housing and transport sectors. Markets are related to wind energy, thermal and photovoltaic energy, heat pumps, wood, bio-diesel, bio-ethanol, biogas, waste energetic valorization, geothermal energy, and hydro-energy. Energy efficiency improvements in the housing sector are related to energetic improvement of existing dwellings, condensing boilers, energetically performing household electrical appliances, and compact fluorescent lamps. In the transport sector, energy efficiency improvements concern rail transports and tramways as well as individual vehicles. New markets are identified and discussed: research and development for renewable energies, energy consultancy and diagnosis, energy efficiency in the office building sector and in the industrial sector

  18. Polarized electrons and the origin of optical activity

    International Nuclear Information System (INIS)

    Bonner, W.A.; Dort, M.A. Van; Yearian, M.R.; Zeman, H.D.; Li, G.C.; Stanford Univ., Calif.

    1976-01-01

    The history of experiments bearing on the origin of optical acitivity in nature by parity non-conservation during the β-decay of radioactive isotopes is briefly reviewed. Following this, we present a more detailed description of our recent published and unpublished data and calculations regarding the generation of optical activity in DL-leucine by means of artificially produced longitudinally polarized electrons from a linear accelerator

  19. Forecast of nuclear energetics

    Energy Technology Data Exchange (ETDEWEB)

    Sikora, W

    1976-01-01

    The forecast concerning the development of nuclear energetics is presented. Some information on economics of nuclear power plants is given. The nuclear fuel reserves are estimated on the background of power resources of the world. The safety and environment protection problems are mentioned.

  20. Artemisinin inhibits chloroplast electron transport activity: mode of action.

    Directory of Open Access Journals (Sweden)

    Adyasha Bharati

    Full Text Available Artemisinin, a secondary metabolite produced in Artemisia plant species, besides having antimalarial properties is also phytotoxic. Although, the phytotoxic activity of the compound has been long recognized, no information is available on the mechanism of action of the compound on photosynthetic activity of the plant. In this report, we have evaluated the effect of artemisinin on photoelectron transport activity of chloroplast thylakoid membrane. The inhibitory effect of the compound, under in vitro condition, was pronounced in loosely and fully coupled thylakoids; being strong in the former. The extent of inhibition was drastically reduced in the presence of uncouplers like ammonium chloride or gramicidin; a characteristic feature described for energy transfer inhibitors. The compound, on the other hand, when applied to plants (in vivo, behaved as a potent inhibitor of photosynthetic electron transport. The major site of its action was identified to be the Q(B; the secondary quinone moiety of photosystemII complex. Analysis of photoreduction kinetics of para-benzoquinone and duroquinone suggest that the inhibition leads to formation of low pool of plastoquinol, which becomes limiting for electron flow through photosystemI. Further it was ascertained that the in vivo inhibitory effect appeared as a consequence of the formation of an unidentified artemisinin-metabolite rather than by the interaction of the compound per se. The putative metabolite of artemisinin is highly reactive in instituting the inhibition of photosynthetic electron flow eventually reducing the plant growth.

  1. Calculation of the energetics of chemical reactions

    Energy Technology Data Exchange (ETDEWEB)

    Dunning, T.H. Jr.; Harding, L.B.; Shepard, R.L.; Harrison, R.J.

    1988-01-01

    To calculate the energetics of chemical reactions we must solve the electronic Schroedinger equation for the molecular conformations of importance for the reactive encounter. Substantial changes occur in the electronic structure of a molecular system as the reaction progresses from reactants through the transition state to products. To describe these changes, our approach includes the following three elements: the use of multiconfiguration self-consistent field wave functions to provide a consistent zero-order description of the electronic structure of the reactants, transition state, and products; the use of configuration interaction techniques to describe electron correlation effects needed to provide quantitative predictions of the reaction energetics; and the use of large, optimized basis sets to provide the flexibility needed to describe the variations in the electronic distributions. With this approach we are able to study reactions involving as many as 5--6 atoms with errors of just a few kcal/mol in the predicted reaction energetics. Predictions to chemical accuracy, i.e., to 1 kcal/mol or less, are not yet feasible, although continuing improvements in both the theoretical methodology and computer technology suggest that this will soon be possible, at least for reactions involving small polyatomic species. 4 figs.

  2. Propagation of Energetic Electrons from the Corona into Interplanetary Space and Type III Radio Emission. Planetary Radio Emissions| PLANETARY RADIO EMISSIONS VII 7|

    OpenAIRE

    Vocks, C.; Breitling, F.; Mann, G.

    2011-01-01

    During solar flares a large amount of electrons with energies greater than 20 keV is generated with a production rate of typically 1036 s-1. A part of them is able to propagate along open magnetic field lines through the corona into interplanetary space. During their travel they emit radio radiation which is observed as type III radio bursts in the frequency range from 100 MHz down to 10 kHz by the WAVES radio spectrometer aboard the spacecraft WIND, for instance. From the drift rates of thes...

  3. An experimental study of the role of autoionizing states of H2 (D2) in the production of energetic protons (deuterons) by electron impact

    International Nuclear Information System (INIS)

    Landau, M.

    1982-06-01

    The autoionizing state study seemed interesting to be taken up again in energy ranges corresponding to formation thresholds, a device well adapted to this range was available concerning electron measurements. Among other things, the overlapping autoionizing states have been displayed; proton kinetic energy distribution appropriate to each state at its formation threshold have been got. The whole of these results represents a proton (and D + ) production mechanism study contribution via autoionizing states. The theory used to describe autoionization cross-section calculations are recalled. Experimental results are presented, discussed, compared to experimental results and theoretical predictions [fr

  4. Rocket measurements of energetic particles in the midlatitude precipitation zone

    Science.gov (United States)

    Voss, H. D.; Smith, L. G.; Braswell, F. M.

    1980-01-01

    Measurements of energetic ion and electron properties as a function of altitude in the midlatitude zone of nighttime energetic particle precipitation are reported. The measurements of particle fluxes, energy spectra and pitch angle distributions were obtained by a Langmuir probe, six energetic particle spectrometers and an electrostatic analyzer on board a Nike Apache rocket launched near the center of the midlatitude zone during disturbed conditions. It is found that the incident flux was primarily absorbed rather than backscattered, and consists of mainly energetic hydrogen together with some helium and a small energetic electron component. Observed differential energy spectra of protons having an exponential energy spectrum, and pitch angle distributions at various altitudes indicate that the energetic particle flux decreases rapidly for pitch angles less than 70 deg. An energetic particle energy flux of 0.002 ergs/sq cm per sec is calculated which indicates the significance of energetic particles as a primary nighttime ionization source for altitudes between 120 and 200 km in the midlatitude precipitation zone.

  5. Active pixel sensor array as a detector for electron microscopy.

    Science.gov (United States)

    Milazzo, Anna-Clare; Leblanc, Philippe; Duttweiler, Fred; Jin, Liang; Bouwer, James C; Peltier, Steve; Ellisman, Mark; Bieser, Fred; Matis, Howard S; Wieman, Howard; Denes, Peter; Kleinfelder, Stuart; Xuong, Nguyen-Huu

    2005-09-01

    A new high-resolution recording device for transmission electron microscopy (TEM) is urgently needed. Neither film nor CCD cameras are systems that allow for efficient 3-D high-resolution particle reconstruction. We tested an active pixel sensor (APS) array as a replacement device at 200, 300, and 400 keV using a JEOL JEM-2000 FX II and a JEM-4000 EX electron microscope. For this experiment, we used an APS prototype with an area of 64 x 64 pixels of 20 microm x 20 microm pixel pitch. Single-electron events were measured by using very low beam intensity. The histogram of the incident electron energy deposited in the sensor shows a Landau distribution at low energies, as well as unexpected events at higher absorbed energies. After careful study, we concluded that backscattering in the silicon substrate and re-entering the sensitive epitaxial layer a second time with much lower speed caused the unexpected events. Exhaustive simulation experiments confirmed the existence of these back-scattered electrons. For the APS to be usable, the back-scattered electron events must be eliminated, perhaps by thinning the substrate to less than 30 microm. By using experimental data taken with an APS chip with a standard silicon substrate (300 microm) and adjusting the results to take into account the effect of a thinned silicon substrate (30 microm), we found an estimate of the signal-to-noise ratio for a back-thinned detector in the energy range of 200-400 keV was about 10:1 and an estimate for the spatial resolution was about 10 microm.

  6. Selective downregulation of mitochondrial electron transport chain activity and increased oxidative stress in human atrial fibrillation.

    Science.gov (United States)

    Emelyanova, Larisa; Ashary, Zain; Cosic, Milanka; Negmadjanov, Ulugbek; Ross, Gracious; Rizvi, Farhan; Olet, Susan; Kress, David; Sra, Jasbir; Tajik, A Jamil; Holmuhamedov, Ekhson L; Shi, Yang; Jahangir, Arshad

    2016-07-01

    Mitochondria are critical for maintaining normal cardiac function, and a deficit in mitochondrial energetics can lead to the development of the substrate that promotes atrial fibrillation (AF) and its progression. However, the link between mitochondrial dysfunction and AF in humans is still not fully defined. The aim of this study was to elucidate differences in the functional activity of mitochondrial oxidative phosphorylation (OXPHOS) complexes and oxidative stress in right atrial tissue from patients without (non-AF) and with AF (AF) who were undergoing open-heart surgery and were not significantly different for age, sex, major comorbidities, and medications. The overall functional activity of the electron transport chain (ETC), NADH:O2 oxidoreductase activity, was reduced by 30% in atrial tissue from AF compared with non-AF patients. This was predominantly due to a selective reduction in complex I (0.06 ± 0.007 vs. 0.09 ± 0.006 nmol·min(-1)·citrate synthase activity(-1), P = 0.02) and II (0.11 ± 0.012 vs. 0.16 ± 0.012 nmol·min(-1)·citrate synthase activity(-1), P = 0.003) functional activity in AF patients. Conversely, complex V activity was significantly increased in AF patients (0.21 ± 0.027 vs. 0.12 ± 0.01 nmol·min(-1)·citrate synthase activity(-1), P = 0.005). In addition, AF patients exhibited a higher oxidative stress with increased production of mitochondrial superoxide (73 ± 17 vs. 11 ± 2 arbitrary units, P = 0.03) and 4-hydroxynonenal level (77.64 ± 30.2 vs. 9.83 ± 2.83 ng·mg(-1) protein, P = 0.048). Our findings suggest that AF is associated with selective downregulation of ETC activity and increased oxidative stress that can contribute to the progression of the substrate for AF. Copyright © 2016 the American Physiological Society.

  7. Dynamic-energetic balance of agricultural tractors: active systems for the measurement of the power requirements in static tests and under field conditions

    Directory of Open Access Journals (Sweden)

    Daniele Pochi

    2013-09-01

    Full Text Available Modern tractors are characterized by the introduction of devices designed to increase the operative performances of the machines, such as systems for monitoring and controlling various functions (through a massive use of electronics and hydraulics, or deputed to improve the comfort of the driver (paying more attention to ergonomics, air-conditioning, noise and vibration. Such devices need energy to be operated, affecting the energetic balance of the tractor. In this context, the availability of suitable methodologies and instrumental systems could be useful to provide objective, accurate and reliable measurements of the performances of the tractors under different conditions, also considering the power requirements from ancillary services and/or simulating the coupling with operating machines. The tests on the performances of tractors are now made using different methods, including the trial codes issued by the OECD Codes. Beyond their undoubted validity, they fix standard test conditions that often do not adequately represent the operative reality, so that, much remains to investigate on the actual performances provided by the tractors. From this point of view and with reference to fixed point tests, a test bench was developed for the measurement of the power required by various devices, such as transmission and air conditioning. It was used in experimental tests on a tracked tractor and on a wheeled tractor, aimed at validating the test device, measuring the power absorption related to the rotational speed of the organs of propulsion and to the characteristics curves, in order to quantify the power drawn by the transmission and by the air conditioning and assess the residual power for other tractor functions. As to field conditions, a study is being conducted at CRA-ING, within the project PTO (Mi.P.A.A.F., to develop a mobile test bench aimed at evaluating the power required by different operations, such as self displacement, traction, use of

  8. INTERACTION BETWEEN TWO CORONAL MASS EJECTIONS IN THE 2013 MAY 22 LARGE SOLAR ENERGETIC PARTICLE EVENT

    International Nuclear Information System (INIS)

    Ding, Liu-Guan; Xu, Fei; Gu, Bin; Zhang, Ya-Nan; Li, Gang; Jiang, Yong; Le, Gui-Ming; Shen, Cheng-Long; Wang, Yu-Ming; Chen, Yao

    2014-01-01

    We investigate the eruption and interaction of two coronal mass ejections (CMEs) during the large 2013 May 22 solar energetic particle event using multiple spacecraft observations. Two CMEs, having similar propagation directions, were found to erupt from two nearby active regions (ARs), AR11748 and AR11745, at ∼08:48 UT and ∼13:25 UT, respectively. The second CME was faster than the first CME. Using the graduated cylindrical shell model, we reconstructed the propagation of these two CMEs and found that the leading edge of the second CME caught up with the trailing edge of the first CME at a height of ∼6 solar radii. After about two hours, the leading edges of the two CMEs merged at a height of ∼20 solar radii. Type II solar radio bursts showed strong enhancement during this two hour period. Using the velocity dispersion method, we obtained the solar particle release (SPR) time and the path length for energetic electrons. Further assuming that energetic protons propagated along the same interplanetary magnetic field, we also obtained the SPR time for energetic protons, which were close to that of electrons. These release times agreed with the time when the second CME caught up with the trailing edge of the first CME, indicating that the CME-CME interaction (and shock-CME interaction) plays an important role in the process of particle acceleration in this event

  9. Active silicon x-ray for measuring electron temperature

    International Nuclear Information System (INIS)

    Snider, R.T.

    1994-07-01

    Silicon diodes are commonly used for x-ray measurements in the soft x-ray region between a few hundred ev and 20 keV. Recent work by Cho has shown that the charge collecting region in an underbiased silicon detector is the depletion depth plus some contribution from a region near the depleted region due to charge-diffusion. The depletion depth can be fully characterized as a function of the applied bias voltage and is roughly proportional to the squart root of the bias voltage. We propose a technique to exploit this effect to use the silicon within the detector as an actively controlled x-ray filter. With reasonable silicon manufacturing methods, a silicon diode detector can be constructed in which the sensitivity of the collected charge to the impinging photon energy spectrum can be changed dynamically in the visible to above the 20 keV range. This type of detector could be used to measure the electron temperature in, for example, a tokamak plasma by sweeping the applied bias voltage during a plasma discharge. The detector samples different parts of the energy spectrum during the bias sweep, and the data collected contains enough information to determine the electron temperature. Benefits and limitations of this technique will be discussed along with comparisons to similar methods for measuring electron temperature and other applications of an active silicon x-ray filter

  10. Relationship between electronic structure and radioprotective activity of some indazoles

    International Nuclear Information System (INIS)

    Sokolov, Yu.A.

    2000-01-01

    The quantum-chemical study of electronic structure of 29 indasoles with complete optimization of geometry and search of quantitative link between the established characteristics and radioprotective activity (RPA) was carried out through the MNDO method with application of multiple linear and nonlinear regression analysis and the basic component method. The equations of correlation relationship between the RPA and electronic characteristics are presented. 10 indasole structures, the forecasted RPA values whereof (survival rate, %) equal 50% and above, are selected. The statistic significance of the obtained correlation equations and their regression coefficients make it possible to conclude, that the established relationships are not accidental and are prospective for forecasting RPA of other close compounds of the indasole series [ru

  11. Measurement of the activity of electron capturing isotopes

    International Nuclear Information System (INIS)

    Szoerenyi, A.

    1980-01-01

    In order to measure precisely the activity of electron capturing isotopes, an equipment was constructed for the detection the X-photons, the Auger- and the conversing electrons by a high-pressure, gas-flow 4π proportional counter. The proportional counter and the NaI(Tl) scintillation counter are placed in a common lead-shielding, thus, the equipment is suited for the measurement of radioisotopes decaying in coincidence. The structure of the proportional counter and of the pressure-control system are detailed. As an example, the energy spectra of a 109 Cd solution, taken at different pressures, are published. At a pressure of 1.1 MPa the 3 peaks are well separated. The results of an international test, in which the radioactivity of a 57 Co sample was determined, are published, too. (L.E.)

  12. Two nitro derivatives of azabenzo[a]pyrene N-oxide: Electronic properties and their relation to mutagenic activity

    Energy Technology Data Exchange (ETDEWEB)

    Ostojić, Bojana D., E-mail: bostojic@chem.bg.ac.rs; Đorđević, Dragana S.

    2015-03-21

    Highlights: • Molecular properties of nitro isomers of azabenzo[a]pyrene N-oxide are investigated. • Stability, ionization potential, electron affinity, and polarizability are determined. • High quality DFT methods are employed. • Nitroreduction, oxidation, and polarizability are not crucial for mutagenicity. • Dipole moment and electronic charge distribution are important for characterization. - Abstract: The equilibrium geometries, relative energies, IR and Raman spectra, vertical ionization potentials (IP), vertical electron affinities (EA), dipole moments (μ), electronic dipole polarizabilities (α), and molecular electrostatic potentials (MEP) of two species that show very high mutagenicity, 1-nitro-6-azabenzo[a]pyrene N-oxide (1-N-6-ABPO) and 3-nitro-6-azabenzo[a]pyrene N-oxide (3-N-6-ABPO), are investigated by means of Density Functional Theory (DFT) using B3LYP functional with different basis sets. The 3-N-6-ABPO isomer was estimated to be much more mutagenic in Salmonella typhimurium tester strain TA98 (396 000 revertants/nmol) than 1-N-6-ABPO (36 100 revertants/nmol) (Fukuhara et al., 1992). The results show that for both isomers the structural, energetic, and vibrational properties are similar. The orientation of the nitro group with respect to the plane of the aromatic system as well as the nitroreduction and oxidation reaction and polarizability seem not be important for the determination of different mutagenic behavior of these isomers. However, the dipole moment of 3-N-6-ABPO is about 3 times that of 1-N-6-ABPO. The larger dipole moment and the different electronic charge distribution of 3-N-6-ABPO compared to 1-N-6-ABPO imply stronger electrostatic and inductive molecular interactions so that the active site of the enzyme involved in the mutagenic activation can more effectively bind 3-N-6-ABPO compared to 1-N-6-ABPO.

  13. Physics of energetic ions

    International Nuclear Information System (INIS)

    1999-01-01

    Physics knowledge (theory and experiment) in energetic particles relevant to design of a reactor scale tokamak is reviewed, and projections for ITER are provided in this Chapter of the ITER Physics Basis. The review includes single particle effects such as classical alpha particle heating and toroidal field ripple loss, as well as collective instabilities that might be generated in ITER plasmas by energetic alpha particles. The overall conclusion is that fusion alpha particles are expected to provide an efficient plasma heating for ignition and sustained burn in the next step device. The major concern is localized heat loads on the plasma facing components produced by alpha particle loss, which might affect their lifetime in a tokamak reactor. (author)

  14. Manipulating the Energetics and Rates of Electron Transfer in Rhodobacter capsulatus Reaction Centers with Asymmetric Pigment Content

    Energy Technology Data Exchange (ETDEWEB)

    Faries, Kaitlyn M. [Department; Dylla, Nicholas P. [Biosciences Division, Argonne National Laboratory, Lemont, Illinois 60439, United States; Hanson, Deborah K. [Biosciences Division, Argonne National Laboratory, Lemont, Illinois 60439, United States; Holten, Dewey [Department; Laible, Philip D. [Biosciences Division, Argonne National Laboratory, Lemont, Illinois 60439, United States; Kirmaier, Christine [Department

    2017-07-17

    Seemingly redundant parallel pathways for electron transfer (ET), composed of identical sets of cofactors, are a cornerstone feature of photosynthetic reaction centers (RCs) involved in light-energy conversion. In native bacterial RCs, both A and B branches house one bacteriochlorophyll (BChl) and one bacteriopheophytin (BPh), but the A branch is used exclusively. Described herein are the results-obtained for two Rhodobacter capsulatus RCs with an unnaturally high degree of cofactor asymmetry, two BPh on the RC's B side and two BChl on the A side. These pigment changes derive, respectively, from the His(M180)Leu mutation [a BPh ((Phi(B)) replaces the B-side BChl (BB)], and the Leu(M212)His mutation [a BChl (beta(A))) replaces the A-side BPh (H-A)]. Additionally, Tyr(M208)Phe was employed to disfavor ET to the A branch; in one mutant, Val(M131)Glu creates a hydrogen bond to H-B to enhance ET to H-B. In both Phi(B) mutants, the decay kinetics of the excited primary ET donor (P*) resolve three populations with lifetimes of similar to 9 ps (50-60%), similar to 40 ps (10-20%), and similar to 200 ps (20-30%), with P+Phi(-)(B) formed predominantly from the 9 ps fraction. The 50-60% yield of P+Phi(B)- is the highest yet observed for a Phi(B)-containing RC. The results provide insight into factors needed for efficient multistep ET.

  15. Energetic utilization of dietary fiber in pigs

    NARCIS (Netherlands)

    Rijnen, M.M.J.A.

    2003-01-01

    The energetic utilization of fermentable dietary fiber (fDF) of different fiber sources and its relation to physical activity and housing conditions was studied in three experiments. In all experiments the daily intake of digestible nutrients, nitrogen and energy balances, heat production, and

  16. Soft Active Materials for Actuation, Sensing, and Electronics

    Science.gov (United States)

    Kramer, Rebecca Krone

    Future generations of robots, electronics, and assistive medical devices will include systems that are soft and elastically deformable, allowing them to adapt their morphology in unstructured environments. This will require soft active materials for actuation, circuitry, and sensing of deformation and contact pressure. The emerging field of soft robotics utilizes these soft active materials to mimic the inherent compliance of natural soft-bodied systems. As the elasticity of robot components increases, the challenges for functionality revert to basic questions of fabrication, materials, and design - whereas such aspects are far more developed for traditional rigid-bodied systems. This thesis will highlight preliminary materials and designs that address the need for soft actuators and sensors, as well as emerging fabrication techniques for manufacturing stretchable circuits and devices based on liquid-embedded elastomers.

  17. Review and Outlook of China Electronic and IT Industry Footprints in IEC International Standardization Activities

    Institute of Scientific and Technical Information of China (English)

    Hu Jingping

    2006-01-01

    @@ Year 2006 is the year marking the 100th anniversary of the founding of International Electrotechnical Commission (IEC). IEC is mainly engaged in the international standardization for electrical and electronic technology field aiming at promoting international trade and technology cooperation and exchange, improving product and service quality, upgrading productivity and protecting the environment as well as human health and safety. Most countries worldwide adopt standards developed and promulgated by IEC, providing a platform to international trade and technical exchange. China has being a member since 1957. Electronic and IT are the most developed and energetic filed in recent decades. Number of IEC TC/SC specialized in electronic and IT amounts up to 52.

  18. Study on regeneration of activated carbon by means of electron radiation

    International Nuclear Information System (INIS)

    Zhu Guanghua; Arai, H.; Hosono, M.

    1991-01-01

    The results of regeneration of activated carbon adsorbing sodium lauryl sulfate (SLS) by 2 MeV electron radiation, and the dependence of the regeneration rate of activated carbon on the electron current intensity, the temperature of sample and the atmosphere were reported. It is shown that regeneration of activated carbon by electron radiation is full of promise

  19. Modelling of electron transport and of sawtooth activity in tokamaks

    International Nuclear Information System (INIS)

    Angioni, C.

    2001-10-01

    Transport phenomena in tokamak plasmas strongly limit the particle and energy confinement and represent a crucial obstacle to controlled thermonuclear fusion. Within the vast framework of transport studies, three topics have been tackled in the present thesis: first, the computation of neoclassical transport coefficients for general axisymmetric equilibria and arbitrary collisionality regime; second, the analysis of the electron temperature behaviour and transport modelling of plasma discharges in the Tokamak a configuration Variable (TCV); third, the modelling and simulation of the sawtooth activity with different plasma heating conditions. The work dedicated to neoclassical theory has been undertaken in order to first analytically identify a set of equations suited for implementation in existing Fokker-Planck codes. Modifications of these codes enabled us to compute the neoclassical transport coefficients considering different realistic magnetic equilibrium configurations and covering a large range of variation of three key parameters: aspect ratio, collisionality, and effective charge number. A comparison of the numerical results with an analytical limit has permitted the identification of two expressions for the trapped particle fraction, capable of encapsulating the geometrical effects and thus enabling each transport coefficient to be fitted with a single analytical function. This has allowed us to provide simple analytical formulae for all the neoclassical transport coefficients valid for arbitrary aspect ratio and collisionality in general realistic geometry. This work is particularly useful for a correct evaluation of the neoclassical contribution in tokamak scenarios with large bootstrap cur- rent fraction, or improved confinement regimes with low anomalous transport and for the determination of the plasma current density profile, since the plasma conductivity is usually assumed neoclassical. These results have been included in the plasma transport code

  20. Carbon nanostructure formation driven by energetic particles

    International Nuclear Information System (INIS)

    Zhu Zhiyuan; Gong Jinlong; Zhu Dezhang

    2006-01-01

    Carbon nanostructures, especially carbon nanotubes (CNTs), have been envisaged to be the building blocks of a variety of nanoscale devices and materials. The inherent nanometer-size and ability of being either metallic or semiconductive of CNTs lead to their application in nanoelectronics. Excellent mechanical characteristics of CNTs suggest their use as structural reinforcements. However, to fully exploit the potential applications, effective means of tailoring CNT properties must be developed. Irradiation of materials with energetic particles beams (ions and electrons) is a standard and important tool for modifying material properties. Irradiation makes it possible to dope the samples, to create local amorphous region or vice versa, recrystallize the lattice and even drive a phase transition. In this paper, we report our results of (1) phase transfromation from carbon nanotubes to nanocrystalline diamond driven by hydrogen plasma, (2) onion-like nanostructure from carbon nanotubes driven by ion beams of several tens keV, and (3) amorphous carbon nanowire network formation by ion beam irradiation. Structural phase transformation from multiwalled carbon nanotubes to nanocrystalline diamond by hydrogen plasma post-treatment was carried out. Ultrahigh equivalent diamond nucleation density of more than 1011 nuclei/cm 2 was obtained. The diamond formation and growth mechanisms were proposed to be the consequence of the formation of sp3 bonded amorphous carbon clusters. The hydrogen chemisorption on curved graphite network and the energy deposited on CNTs by continuous impingement of activated molecular or atomic hydrogen are responsible for the formation of amorphous carbon matrix. Diamond nucleates and grows in the way similar to that of diamond chemical vapor deposition processes on amorphous carbon films. Furthermore, single crystalline diamond nanorods of 4-8 nm in diameter and up to 200 nm in length have been successfully synthesized by hydrogen plasma post

  1. Changes in mitochondrial electron transport chain activity during insect metamorphosis.

    Science.gov (United States)

    Chamberlin, M E

    2007-02-01

    The midgut of the tobacco hornworm (Manduca sexta) is a highly aerobic tissue that is destroyed by programmed cell death during larval-pupal metamorphosis. The death of the epithelium begins after commitment to pupation, and the oxygen consumption of isolated midgut mitochondria decreases soon after commitment. To assess the role of the electron transport chain in this decline in mitochondrial function, the maximal activities of complexes I-IV of the respiratory chain were measured in isolated midgut mitochondria. Whereas there were no developmental changes in the activity of complex I or III, activities of complexes II and IV [cytochrome c oxidase (COX)] were higher in mitochondria from precommitment than postcommitment larvae. This finding is consistent with a higher rate of succinate oxidation in mitochondria isolated from precommitment larvae and reveals that the metamorphic decline in mitochondrial respiration is due to the targeted destruction or inactivation of specific sites within the mitochondria, rather than the indiscriminate destruction of the organelles. The COX turnover number (e- x s(-1) x cytochrome aa3(-1)) was greater for the enzyme from precommitment than postcommitment larvae, indicating a change in the enzyme structure and/or its lipid environment during the early stages of metamorphosis. The turnover number of COX in the intact mitochondria (in organello COX) was also lower in postcommitment larvae. In addition to changes in the protein or membrane phospholipids, the metamorphic decline in this rate constant may be a result of the observed loss of endogenous cytochrome c.

  2. Energetic cost of communication.

    Science.gov (United States)

    Stoddard, Philip K; Salazar, Vielka L

    2011-01-15

    Communication signals may be energetically expensive or inexpensive to produce, depending on the function of the signal and the competitive nature of the communication system. Males of sexually selected species may produce high-energy advertisement signals, both to enhance detectability and to signal their size and body condition. Accordingly, the proportion of the energy budget allocated to signal production ranges from almost nothing for many signals to somewhere in excess of 50% for acoustic signals in short-lived sexually selected species. Recent data from gymnotiform electric fish reveal mechanisms that regulate energy allocated to sexual advertisement signals through dynamical remodeling of the excitable membranes in the electric organ. Further, males of the short-lived sexually selected species, Brachyhypopomus gauderio, trade off among different metabolic compartments, allocating energy to signal production while reducing energy used in other metabolic functions. Female B. gauderio, by contrast, do not trade off energy between signaling and other functions. To fuel energetically expensive signal production, we expect a continuum of strategies to be adopted by animals of different life history strategies. Future studies should explore the relation between life history and energy allocation trade-offs.

  3. Energetics Manufacturing Technology Center (EMTC)

    Data.gov (United States)

    Federal Laboratory Consortium — The Energetics Manufacturing Technology Center (EMTC), established in 1994 by the Office of Naval Research (ONR) Manufacturing Technology (ManTech) Program, is Navy...

  4. Energetic particles at venus: galileo results.

    Science.gov (United States)

    Williams, D J; McEntire, R W; Krimigis, S M; Roelof, E C; Jaskulek, S; Tossman, B; Wilken, B; Stüdemann, W; Armstrong, T P; Fritz, T A; Lanzerotti, L J; Roederer, J G

    1991-09-27

    At Venus the Energetic Particles Detector (EPD) on the Galileo spacecraft measured the differential energy spectra and angular distributions of ions >22 kiloelectron volts (keV) and electrons > 15 keV in energy. The only time particles were observed by EPD was in a series of episodic events [0546 to 0638 universal time (UT)] near closest approach (0559:03 UT). Angular distributions were highly anisotropic, ordered by the magnetic field, and showed ions arriving from the hemisphere containing Venus and its bow shock. The spectra showed a power law form with intensities observed into the 120- to 280-keV range. Comparisons with model bow shock calculations show that these energetic ions are associated with the venusian foreshock-bow shock region. Shock-drift acceleration in the venusian bow shock seems the most likely process responsible for the observed ions.

  5. Electron localization in water clusters

    International Nuclear Information System (INIS)

    Landman, U.; Barnett, R.N.; Cleveland, C.L.; Jortner, J.

    1987-01-01

    Electron attachment to water clusters was explored by the quantum path integral molecular dynamics method, demonstrating that the energetically favored localization mode involves a surface state of the excess electron, rather than the precursor of the hydrated electron. The cluster size dependence, the energetics and the charge distribution of these novel electron-cluster surface states are explored. 20 refs., 2 figs., 1 tab

  6. GLOBAL ENERGETICS OF SOLAR FLARES. IV. CORONAL MASS EJECTION ENERGETICS

    International Nuclear Information System (INIS)

    Aschwanden, Markus J.

    2016-01-01

    This study entails the fourth part of a global flare energetics project, in which the mass m cme , kinetic energy E kin , and the gravitational potential energy E grav of coronal mass ejections (CMEs) is measured in 399 M and X-class flare events observed during the first 3.5 years of the Solar Dynamics Observatory (SDO) mission, using a new method based on the EUV dimming effect. EUV dimming is modeled in terms of a radial adiabatic expansion process, which is fitted to the observed evolution of the total emission measure of the CME source region. The model derives the evolution of the mean electron density, the emission measure, the bulk plasma expansion velocity, the mass, and the energy in the CME source region. The EUV dimming method is truly complementary to the Thomson scattering method in white light, which probes the CME evolution in the heliosphere at r ≳ 2 R ⊙ , while the EUV dimming method tracks the CME launch in the corona. We compare the CME parameters obtained in white light with the LASCO/C2 coronagraph with those obtained from EUV dimming with the Atmospheric Imaging Assembly onboard the SDO for all identical events in both data sets. We investigate correlations between CME parameters, the relative timing with flare parameters, frequency occurrence distributions, and the energy partition between magnetic, thermal, nonthermal, and CME energies. CME energies are found to be systematically lower than the dissipated magnetic energies, which is consistent with a magnetic origin of CMEs.

  7. Electron beam injection during active experiments. 1. Electromagnetic wave emissions

    International Nuclear Information System (INIS)

    Winglee, R.M.; Kellogg, P.J.

    1990-01-01

    During the active injection of an electron beam, a broad spectrum of waves is generated. In this paper examples of spectra from the recent Echo 7 experiment are presented. These results show that the characteristics of the emissions can change substantially with altitude. Two-dimensional (three velocity) relativistic electromagnetic particle simulations are used to investigate the changes in the plasma conditions required to account for the observed spectral variations. It is shown that many of these variations can be accounted for by assuming that the ratio of the electron plasma frequency ω pe to cyclotron frequency Ω e is less than unity at the lower altitudes of about 200 km and near or above unity at apogee of about 300 km. In the former case, whistlers with a cutoff at ω pe , lower hybrid and plasma waves are driven by the parallel beam energy while electromagnetic fundamental z mode and second harmonic x mode and electrostatic upper hybrid waves are driven by the perpendicular beam energy through the master instability. E x B drifts driven by perpendicular electric fields associated with the beam-plasma interaction can also be important in generating maser emission, particularly for field-aligned injection where there is no intrinsic perpendicular beam energy. The power in the electrostatic waves is a few percent of the beam energy and that in the electromagnetic waves a few tenths of a percent. In the latter case, where ω pe /Ω e increases above unity, emission in the fundamental z mode and second harmonic x mode become suppressed

  8. About Russian nuclear energetic perspectives

    International Nuclear Information System (INIS)

    Laletin, N.I.

    2003-01-01

    My particular view about Russian nuclear energetics perspectives is presented. The nearest and the further perspectives are considered. The arguments are adduced that the most probable scenario of nuclear energetic development is its stabilization in the near future. Fur further development the arguments of supporters and opponents of nuclear energetics are analyzed. Three points of view are considered. The first point of view that there is not alternative for nuclear energetics. My notes are the following ones. a) I express a skeptic opinion about a statement of quick exhaustion of fossil organic fuel recourses and corresponding estimations are presented. b) It is expressed skeptic opinion about the statement that nuclear energetics can have a visual influence on ''steam effect''. c) I agree that nuclear energetics is the most ecological technology for normal work but however we can't disregard possibilities of catastrophic accidents. The second point of view that the use of nuclear energetics can't have the justification. I adduce the arguments contrary to this statement. The third point of view that nuclear energetics is a usual technology and the only criteria for discussions about what dimension and where one ought develop it is total cost of its unit. Expressed an opinion that the deceived for the choose of a way the skill of the estimate correctly and optimized so named the external parts of the unit energy costs for different energy technologies. (author)

  9. Rural energetic development: cuban experience

    International Nuclear Information System (INIS)

    Aguilera Barciela, M.

    1994-01-01

    The development of electro energetic national system in Cuba has been directed to the following objectives: to brake the rural population's exodus toward the cities, electrification of dairy farm, interconnection to the system electro energetic of all the sugar central production, these improves the rural population's conditions life

  10. Economical aspects of nuclear energetics

    International Nuclear Information System (INIS)

    Celinski, Z.

    2000-01-01

    The economical aspects of nuclear power generation in respect to costs of conventional energetics have been discussed in detail. The costs and competitiveness of nuclear power have been considered on the base of worldwide trends taking into account investment and fuel costs as well as 'social' costs being result of impact of different types of energetics on environment, human health etc

  11. Effects of the electron-phonon coupling activation in collision cascades

    Energy Technology Data Exchange (ETDEWEB)

    Zarkadoula, Eva, E-mail: zarkadoulae@ornl.gov [Materials Science & Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Samolyuk, German [Materials Science & Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Weber, William J. [Materials Science & Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Department of Materials Science & Engineering, University of Tennessee, Knoxville, TN 37996 (United States)

    2017-07-15

    Using the two-temperature (2T-MD) model in molecular dynamics simulations, we investigate the condition of switching the electronic stopping term off when the electron-phonon coupling is activated in the damage production due to 50 keV Ni ion cascades in Ni and equiatomic NiFe. Additionally, we investigate the effect of the electron-phonon coupling activation time in the damage production. We find that the switching condition has negligible effect in the produced damage, while the choice of the activation time of the electron-phonon coupling can affect the amount of surviving damage. - Highlights: •The electron-phonon interactions in irradiation affect the energy dissipation. •The resulting damage depends on the electron-phonon interaction activation time. •The electronic stopping acts on the ions before the electron-phonon interactions.

  12. Observations of Energetic Particle Escape at the Magnetopause: Early Results from the MMS Energetic Ion Spectrometer (EIS)

    Science.gov (United States)

    Cohen, I. J.; Mauk, B. H.; Anderson, B. J.; Westlake, J. H.; Sibeck, David Gary; Giles, Barbara L.; Pollock, C. J.; Turner, D. L.; Fennell, J. F.; Blake, J. B.; hide

    2016-01-01

    Energetic (greater than tens of keV) magnetospheric particle escape into the magnetosheath occurs commonly, irrespective of conditions that engender reconnection and boundary-normal magnetic fields. A signature observed by the Magnetospheric Multiscale (MMS) mission, simultaneous monohemispheric streaming of multiple species (electrons, H+, Hen+), is reported here as unexpectedly common in the dayside, dusk quadrant of the magnetosheath even though that region is thought to be drift-shadowed from energetic electrons. This signature is sometimes part of a pitch angle distribution evolving from symmetric in the magnetosphere, to asymmetric approaching the magnetopause, to monohemispheric streaming in the magnetosheath. While monohemispheric streaming in the magnetosheath may be possible without a boundary-normal magnetic field, the additional pitch angle depletion, particularly of electrons, on the magnetospheric side requires one. Observations of this signature in the dayside dusk sector imply that the static picture of magnetospheric drift-shadowing is inappropriate for energetic particle dynamics in the outer magnetosphere.

  13. Mammalian energetics. Flexible energetics of cheetah hunting strategies provide resistance against kleptoparasitism.

    Science.gov (United States)

    Scantlebury, David M; Mills, Michael G L; Wilson, Rory P; Wilson, John W; Mills, Margaret E J; Durant, Sarah M; Bennett, Nigel C; Bradford, Peter; Marks, Nikki J; Speakman, John R

    2014-10-03

    Population viability is driven by individual survival, which in turn depends on individuals balancing energy budgets. As carnivores may function close to maximum sustained power outputs, decreased food availability or increased activity may render some populations energetically vulnerable. Prey theft may compromise energetic budgets of mesopredators, such as cheetahs and wild dogs, which are susceptible to competition from larger carnivores. We show that daily energy expenditure (DEE) of cheetahs was similar to size-based predictions and positively related to distance traveled. Theft at 25% only requires cheetahs to hunt for an extra 1.1 hour per day, increasing DEE by just 12%. Therefore, not all mesopredators are energetically constrained by direct competition. Other factors that increase DEE, such as those that increase travel, may be more important for population viability. Copyright © 2014, American Association for the Advancement of Science.

  14. Electrical initiation of an energetic nanolaminate film

    Science.gov (United States)

    Tringe, Joseph W.; Gash, Alexander E.; Barbee, Jr., Troy W.

    2010-03-30

    A heating apparatus comprising an energetic nanolaminate film that produces heat when initiated, a power source that provides an electric current, and a control that initiates the energetic nanolaminate film by directing the electric current to the energetic nanolaminate film and joule heating the energetic nanolaminate film to an initiation temperature. Also a method of heating comprising providing an energetic nanolaminate film that produces heat when initiated, and initiating the energetic nanolaminate film by directing an electric current to the energetic nanolaminate film and joule heating the energetic nanolaminate film to an initiation temperature.

  15. Estimating Instantaneous Energetic Cost During Gait Adaptation

    Science.gov (United States)

    2014-08-31

    energetic cost. Its 327   accuracy benefits from a personalized model for each subject, but for some situations, it may suffice to 328   use the...Activity 380   Patterns During Robotic - and Therapist-Assisted Treadmill Walking in Individuals With 381   Incomplete Spinal Cord Injury. Phys Ther 86...of level walking with powered ankle 410   exoskeletons . Journal of Experimental Biology 211: 1402–1413, 2008. 411   25. Schmalz T, Blumentritt S

  16. Light and electron microscope assessment of the lytic activity of ...

    African Journals Online (AJOL)

    The Microcystis cells were exposed to copper, B. mycoides B16 and Triton X-100, in order to ascertain the level of cell membrane damage. The membrane cell damage ... The electron microscopy observations appeared to reveal at least two mechanisms of Microcystis lysis (contact and parasitism). The light and electron ...

  17. Analysis of the energetic sector through the national energetic matrix

    International Nuclear Information System (INIS)

    Garzon Lozano, Enrique

    2007-01-01

    The author shows the results of the national energetic balance 1975-2005, through the energetic matrix of the country, giving an annual growth of 5.1% in this period of offer of primary energy, where the mineral coal participates with 9,6%, the hydraulic energy with 4,8%, natural gas with 4,2%, trash with 2,4% and petroleum with 2,2%, while the firewood fell in 0,5%

  18. Formulation of the energetic spectral distribution of in pile neutron flux (energies greater than a few hundred electron volts) (1963); Formulation des repartitions spectrales energetiques de flux neutroniques en pile (energies superieures a quelques centaines d'electrons-volts) (1963)

    Energy Technology Data Exchange (ETDEWEB)

    Genthon, J P [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1964-07-01

    In the present report an expression is deduced for the spectral distribution of flux of over a few hundred electron volts; it is valid for most cases of thermal neutron reactors. This expression is: {psi}(E) = K [{psi}{sub o}(E) + h {psi}{sub e}(E)] {psi}{sub o}(E) is the so-called 'homogeneous' constituent of the flux; it corresponds approximately to the case of an infinite homogeneous medium; it is of the type: Y(V - E) e{sup (b{radical}}{sup E)}/E + Y(E-V) F E{sup {upsilon}} e{sup -{beta}}{sup E} The parameters V and F are such that {psi}{sub o}(E) and its derivative are continuous at the junction energy V. {psi}{sub e}(E) is the 'heterogeneous' constituent of the flux; it is of the type: E{sup {upsilon}} e{sup -{beta}}{sup E}. The various parameters of {psi}(E) are on the one hand characteristic of the nature of the reactor moderator, and on the other hand determined by a resonant flux measurement and one, or possibly two, measurements using a fast neutron threshold detector. We have been led furthermore to define an expression for the threshold reaction section which is more exact than the conventional transition function. (author) [French] Il est etabli, dans le present rapport, une formulation {psi}(E) des repartitions spectrales de flux au-dessus de quelques centaines d'electron-s volts, valable dans la majeure partie des cas de piles dites a neutrons thermiques. Cette formulation s'exprime: {psi}(E) = K [{psi}{sub o}(E) + h {psi}{sub e}(E)] {psi}{sub o}(E) est la composante dite 'homogene' du flux; elle correspond a peu pres au cas d'un milieu infini homogene; elle est du type: Y(V - E) e{sup (b{radical}}{sup E)}/E + Y(E-V) F E{sup {upsilon}} e{sup -{beta}}{sup E} les parametres V et F sont tels que {psi}{sub o}(E) et sa derivee soient continues a l'energie de jonction V. {psi}{sub e} est la composante dite 'heterogene' du flux ; elle est du type: E{sup {upsilon}} e{sup -{beta}}{sup E}. Les differents parametres de {psi}(E) sont, d'une part

  19. Electron-capture ratios in radio-active decay

    International Nuclear Information System (INIS)

    Pelt, J. van.

    1978-01-01

    A review of the theory of electron capture is given and expressions for the electron-capture ratios derived. Attention is paid to the calculations of exchange and overlap correction factors. The theoretical results are then compared with experimental values on the basis of two recently published compilations. The experimental set-up used in this investigation is described and the analysis of the scintillation spectra discussed. Measurements on 131 Ba, 106 Agsup(m) and 196 Au are described and values derived for the exchange and overlap corrections and for the atomic electron-capture transition energy Qsub(EC). (Auth.)

  20. Energetic policies 2005-2030

    International Nuclear Information System (INIS)

    2008-01-01

    This power point exhibition shows the following topics: energy analysis, production and use, supply and demand, consumption, energy sources, energetic prospective of Uruguay country, medium and long term perspectives.

  1. 76 FR 40454 - Proposed Information Collection (VSO Access to VHA Electronic Health Records) Activity; Comment...

    Science.gov (United States)

    2011-07-08

    ... Access to VHA Electronic Health Records) Activity; Comment Request AGENCY: Veterans Health Administration... Access to VHA Electronic Health Records, VA Form 10- 0400. OMB Control Number: 2900-0710. Type of Review... were granted power of attorney by veterans who have medical information recorded in VHA electronic...

  2. Synchrotron radiation and free electron laser activities in Novosibirsk

    International Nuclear Information System (INIS)

    Korchuganov, V.N.; Kulipanov, G.N.; Mezentsev, N.A.; Oreshkov, A.D.; Panchenko, V.E.; Pindyurin, V.F.; Skrinskij, A.N.; Sheromov, M.A.; Vinokurov, N.A.; Zolotarev, K.V.

    1994-01-01

    The results of studies realized in the Siberian synchrotron radiation centre within the frameworks of wide program of synchrotron radiation and free electron laser research are summarized. The technical information on the VEPP-2M, VEPP-3 and VEPP-4M storage rings used as synchrotron radiation sources is given. 10 refs.; 8 figs.; 12 tabs

  3. Beyond usage: understanding the use of electronic journals on the basis of information activity analysis. Electronic journals, Use studies, Information activity, Scientific communication

    Directory of Open Access Journals (Sweden)

    Annaïg Mahé

    2004-01-01

    Full Text Available In this article, which reports the second part of a two-part study of the use of electronic journals by researchers in two French research institutions, we attempt to explain the integration of the use of electronic journals in the scientists' information habits, going beyond usage analysis. First, we describe how the development of electronic journals use follows a three-phase innovation process - research-development, first uses, and technical acculturation. Then, we attempt to find more significant explanatory factors, and emphasis is placed on the wider context of information activity. Three main information activity types are outlined - marginal, parallel, and integrated. Each of these types corresponds to a particular attitude towards scientific information and to different levels of electronic journal use.

  4. Effective charge of energetic ions in metals

    International Nuclear Information System (INIS)

    Kitagawa, M.; Brandt, W.

    1983-01-01

    The effective charge of energetic ion, as derived from stopping power of metals, is calculated by use of a dielectronic-response function method. The electronic distribution in the ion is described through the variational principle in a statistical approximation. The dependences of effective charge on the ion velocity, atomic number and r/sub s/-value of metal are derived at the low-velocity region. The effective charge becomes larger than the real charge of ion due to the close collisions. We obtain the quasi-universal equation of the fractional effective electron number of ion as a function of the ratio between the ionic size and the minimum distance approach. The comparsion between theoretical and experimental results of the effective charge is performed for the cases of N ion into Au, C and Al. We also discuss the equipartition rule of partially ionized ion at the high-velocity region

  5. Aloe vera in active and passive regions of electronic devices towards a sustainable development

    Science.gov (United States)

    Lim, Zhe Xi; Sreenivasan, Sasidharan; Wong, Yew Hoong; Cheong, Kuan Yew

    2017-07-01

    The increasing awareness towards sustainable development of electronics has driven the search for natural bio-organic materials in place of conventional electronic materials. The concept of using natural bio-organic materials in electronics provides not only an effective solution to address global electronic waste crisis, but also a compelling template for sustainable electronics manufacturing. This paper attempts to provide an overview of using Aloe vera gel as a natural bio-organic material for various electronic applications. Important concepts such as responses of living Aloe vera plant towards electrical stimuli and demonstrations of Aloe vera films as passive and active regions of electronic devices are highlighted in chronological order. The biodegradability and biocompatibility of Aloe vera can bring the world a step closer towards the ultimate goal of sustainable development of electronic devices from "all-natural" materials.

  6. Topology Optimization of an Actively Cooled Electronics Section for Downhole Tools

    DEFF Research Database (Denmark)

    Soprani, Stefano; Klaas Haertel, Jan Hendrik; Lazarov, Boyan Stefanov

    2015-01-01

    Active cooling systems represent a possible solution to the electronics overheating that occurs in wireline downhole tools operating in high temperature oil and gas wells. A Peltier cooler was chosen to maintain the downhole electronics to a tolerable temperature, but its integration into the dow......Active cooling systems represent a possible solution to the electronics overheating that occurs in wireline downhole tools operating in high temperature oil and gas wells. A Peltier cooler was chosen to maintain the downhole electronics to a tolerable temperature, but its integration......, according to the topology optimization results and assembly constraints, and compared to the optimized cases....

  7. Adrenaline and reactive oxygen species elicit proteome and energetic metabolism modifications in freshly isolated rat cardiomyocytes

    International Nuclear Information System (INIS)

    Costa, Vera Marisa; Silva, Renata; Tavares, Ludgero Canario; Vitorino, Rui; Amado, Francisco; Carvalho, Felix; Bastos, Maria de Lourdes; Carvalho, Marcia; Carvalho, Rui Albuquerque; Remiao, Fernando

    2009-01-01

    cytosolic NADH/NAD + ratio. Furthermore, an increase in manganese SOD expression and total SOD activity occurred in the ADR group, as the increase in the mitochondrial complexes presumably led to higher 'electron leakage'. The modifications in proteins, enzymes activity, and energetic metabolism were indicative that different pathways are activated by catecholamines and ROS. These alterations altogether determine the I/R and HF specific features and contribute for the initiation or aggravation of those cardiopathologic conditions.

  8. Second School of Nuclear Energetics

    International Nuclear Information System (INIS)

    2009-01-01

    At 3-5 Nov 2009 Institute of Nuclear Energy POLATOM, Association of Polish Electrical Engineers (SEP) and Polish Nuclear Society have organized Second School of Nuclear Energetics. 165 participants have arrived from all Poland and represented both different central institutions (e.g. ministries) and local institutions (e.g. Office of Technical Inspection, The Voivodship Presidential Offices, several societies, consulting firms or energetic enterprises). Students from the Warsaw Technical University and Gdansk Technical University, as well as the PhD students from the Institute of Nuclear Chemistry and Technology (Warsaw) attended the School. 20 invited lectures presented by eminent Polish specialists concerned basic problems of nuclear energetics, nuclear fuel cycle and different problems of the NPP construction in Poland. [pl

  9. The Principle of Energetic Consistency

    Science.gov (United States)

    Cohn, Stephen E.

    2009-01-01

    A basic result in estimation theory is that the minimum variance estimate of the dynamical state, given the observations, is the conditional mean estimate. This result holds independently of the specifics of any dynamical or observation nonlinearity or stochasticity, requiring only that the probability density function of the state, conditioned on the observations, has two moments. For nonlinear dynamics that conserve a total energy, this general result implies the principle of energetic consistency: if the dynamical variables are taken to be the natural energy variables, then the sum of the total energy of the conditional mean and the trace of the conditional covariance matrix (the total variance) is constant between observations. Ensemble Kalman filtering methods are designed to approximate the evolution of the conditional mean and covariance matrix. For them the principle of energetic consistency holds independently of ensemble size, even with covariance localization. However, full Kalman filter experiments with advection dynamics have shown that a small amount of numerical dissipation can cause a large, state-dependent loss of total variance, to the detriment of filter performance. The principle of energetic consistency offers a simple way to test whether this spurious loss of variance limits ensemble filter performance in full-blown applications. The classical second-moment closure (third-moment discard) equations also satisfy the principle of energetic consistency, independently of the rank of the conditional covariance matrix. Low-rank approximation of these equations offers an energetically consistent, computationally viable alternative to ensemble filtering. Current formulations of long-window, weak-constraint, four-dimensional variational methods are designed to approximate the conditional mode rather than the conditional mean. Thus they neglect the nonlinear bias term in the second-moment closure equation for the conditional mean. The principle of

  10. Energetic magnetospheric protons in the plasma depletion layer

    International Nuclear Information System (INIS)

    Fuselier, S.A.

    1992-01-01

    Interplanetary magnetic field draping against the Earth's dayside subsolar magnetopause creates a region of reduced plasma density and increased magnetic field called the plasma depletion layer. In this region, leakage of energetic ions from the Earth's magnetosphere onto magnetic field lines in the plasma depletion layer can be studied without interference from ions accelerated at the Earth's quasi-parallel bow shock. Active Magnetospheric Particle Tracer Experiment/Charge Composition Explorer (AMPTE/CCE) observations for 13 plasma depletion layer events are used to determine the characteristics of energetic protons between a few keV/e and ∼100keV/e leaked from the magnetosphere. Results indicate that the leaked proton distributions resemble those in the magnetosphere except that they have lower densities and temperatures and much higher velocities parallel (or antiparallel) and perpendicular to the magnetic field. Compared to the low-energy magnetosheath proton distributions present in the depletion layer, the leaked energetic proton distributions typically have substantially higher flow velocities along the magnetic field indicate that the leaked energetic proton distributions to contribute to the energetic proton population seen upstream and downstream from the quasi-parallel bow shock. However, their contribution is small compared to the contribution from acceleration of protons at the bow shock because the leaked proton densities are on the order of 10 times smaller than the energetic proton densities typically observed in the vicinity of the quasi-parallel bow shock

  11. Multi-body forces and the energetics of transition metals, alloys, and semiconductors

    International Nuclear Information System (INIS)

    Carlsson, A.E.

    1992-01-01

    Progress over the past year is divided into 3 areas: potential-energy functions for transition-metal aluminides; electronic structure and energetics of complex structures and quasicrystals; and ceramic materials (PdO, PtO)

  12. Kinetic Simulation and Energetic Neutral Atom Imaging of the Magnetosphere

    Science.gov (United States)

    Fok, Mei-Ching H.

    2011-01-01

    Advanced simulation tools and measurement techniques have been developed to study the dynamic magnetosphere and its response to drivers in the solar wind. The Comprehensive Ring Current Model (CRCM) is a kinetic code that solves the 3D distribution in space, energy and pitch-angle information of energetic ions and electrons. Energetic Neutral Atom (ENA) imagers have been carried in past and current satellite missions. Global morphology of energetic ions were revealed by the observed ENA images. We have combined simulation and ENA analysis techniques to study the development of ring current ions during magnetic storms and substorms. We identify the timing and location of particle injection and loss. We examine the evolution of ion energy and pitch-angle distribution during different phases of a storm. In this talk we will discuss the findings from our ring current studies and how our simulation and ENA analysis tools can be applied to the upcoming TRIO-CINAMA mission.

  13. Oxide-cathode activation and surface temperature calculation of electron cooler

    International Nuclear Information System (INIS)

    Li Jie; Yang Xiaodong; Mao Lijun; Li Guohong; Yuan Youjin; Liu Zhanwen; Zhang Junhui; Yang Xiaotian; Ma Xiaoming; Yan Tailai

    2011-01-01

    The pollution on electron gun ceramic insulation of electron cooler restricted the operation of electron cooler at HIRFL-CSR main ring. To cool and accumulate ion beam well, the pollution was cleared and a new oxide-coated cathode was assembled. The processes of cathode replacement,vacuum chamber baking-out, and thermal decomposition of coating binders and alkaline earth metal carbonates, and cathode activation are presented. The electron gun perveance of 10.6 μA/V 1.5 was attained under the heating power of 60 W. The typical surface temperature of oxide-coated cathode that is calculated through grey-body radiation is 1 108 K which shows a comparable result to the experimental measurement 1 078 K. The perveance growth of electron gun during the electron cooler operation is also explained by partial activation of the cathode. (authors)

  14. Study on Effects of Electron Donors on Phosphine Production from Anaerobic Activated Sludge

    Directory of Open Access Journals (Sweden)

    Jianping Cao

    2017-07-01

    Full Text Available The effects of different types and concentrations of electron donors (glucose, starch, methanol and sodium acetate on the formation of phosphine from anaerobic activated sludge that has been domesticated for a prolonged period were studied in small batch experiments. The results show that types and concentrations of electron donor have significant effects on the production of phosphine from anaerobic activated sludge. Among them, glucose was the most favourable electron donor, whereas sodium acetate was the least favourable electron donor for the removal of phosphorus and the production of phosphine. Higher concentrations of electron donors were more favourable for the reduction of phosphate into phosphine, and supplying more than nine times the amount of electron donor as theoretically required for the reduction of phosphate into phosphine was favourable for the production of phosphine.

  15. Energetics of dislocation transformations in hcp metals

    International Nuclear Information System (INIS)

    Wu, Zhaoxuan; Yin, Binglun; Curtin, W.A.

    2016-01-01

    Dislocation core structures of hcp metals are highly complex and differ significantly among the hcp family. Some dislocations undergo unconventional transformations that have significant effects on the material plastic flow. Here, the energetics of dislocation dissociations are analyzed in a general anisotropic linear elastic theory framework for transformations in which changes in the partial Burgers vectors are small. Quantitative analyses on various transformations are made using DFT-computed stacking fault energies and partial Burgers vectors. Specifically, possible transformations of the mixed, edge, and screw 〈c+a〉 and screw 〈a〉 dislocations in 6 hcp metals (Mg, Ti, Zr, Re, Zn, Cd) are studied. Climb dissociation of mixed or edge 〈c+a〉 dislocations to the Basal plane is energetically favorable in all 6 metals and thus only limited by thermal activation. The 〈c+a〉 screw dislocation is energetically preferable on Pyramidal I for Ti, Zr, and Re, and on Pyramidal II for Zn and Cd. In Mg, the energy difference between screw 〈c+a〉 on Pyramidal I and II planes is small, suggesting relatively easy cross-slip. For the screw 〈a〉, Basal dissociation is energetically favorable in Mg, Re, Zn and Cd, while Prism dissociation is strongly favorable in Ti and Zr. Only Ti, Zr and Re show a metastable state for dissociation on the Prism plane, and the energy difference between screw 〈a〉 on the Prism and Pyramidal I planes is relatively small in all systems, suggesting relatively easy cross-slip of 〈a〉 in Ti and Zr. The elastic analysis thus provides a single framework able to capture the controlling energetics for different dissociations and slip systems in hcp metals. When the calculated energy differences are very small, the results point to the need for detailed modeling of the atomistic core structure. Moreover, the analyses rationalize broad experimental observations on dominant slip systems and dislocation behaviours, and provide

  16. Stable aqueous dispersions of optically and electronically active phosphorene.

    Science.gov (United States)

    Kang, Joohoon; Wells, Spencer A; Wood, Joshua D; Lee, Jae-Hyeok; Liu, Xiaolong; Ryder, Christopher R; Zhu, Jian; Guest, Jeffrey R; Husko, Chad A; Hersam, Mark C

    2016-10-18

    Understanding and exploiting the remarkable optical and electronic properties of phosphorene require mass production methods that avoid chemical degradation. Although solution-based strategies have been developed for scalable exfoliation of black phosphorus, these techniques have thus far used anhydrous organic solvents in an effort to minimize exposure to known oxidants, but at the cost of limited exfoliation yield and flake size distribution. Here, we present an alternative phosphorene production method based on surfactant-assisted exfoliation and postprocessing of black phosphorus in deoxygenated water. From comprehensive microscopic and spectroscopic analysis, this approach is shown to yield phosphorene dispersions that are stable, highly concentrated, and comparable to micromechanically exfoliated phosphorene in structure and chemistry. Due to the high exfoliation efficiency of this process, the resulting phosphorene flakes are thinner than anhydrous organic solvent dispersions, thus allowing the observation of layer-dependent photoluminescence down to the monolayer limit. Furthermore, to demonstrate preservation of electronic properties following solution processing, the aqueous-exfoliated phosphorene flakes are used in field-effect transistors with high drive currents and current modulation ratios. Overall, this method enables the isolation and mass production of few-layer phosphorene, which will accelerate ongoing efforts to realize a diverse range of phosphorene-based applications.

  17. CMOS Active Pixel Sensor Star Tracker with Regional Electronic Shutter

    Science.gov (United States)

    Yadid-Pecht, Orly; Pain, Bedabrata; Staller, Craig; Clark, Christopher; Fossum, Eric

    1996-01-01

    The guidance system in a spacecraft determines spacecraft attitude by matching an observed star field to a star catalog....An APS(active pixel sensor)-based system can reduce mass and power consumption and radiation effects compared to a CCD(charge-coupled device)-based system...This paper reports an APS (active pixel sensor) with locally variable times, achieved through individual pixel reset (IPR).

  18. Correlated observations of intensified whistler waves and electron acceleration around the geostationary orbit

    International Nuclear Information System (INIS)

    Xiao Fuliang; He Zhaoguo; Tang Lijun; Zong Qiugang; Wang Chengrui; Su Zhenpeng

    2012-01-01

    We report correlated observations of enhanced whistler waves and energetic electron acceleration collected by multiple satellites specifically near the geostationary orbit during the 7–10 November 2004 superstorms, together with multi-site observations of ULF wave power measured on the ground. Energetic (>0.6 MeV) electron fluxes are found to increase significantly during the recovery phase, reaching a peak value by ∼100 higher than the prestorm level. In particular, such high electron flux corresponds to intensified whistler wave activities but to the weak ULF wave power. This result suggests that wave–particle interaction appears to be more important than inward radial diffusion in acceleration of outer radiation belt energetic electrons in this event, assisting to better understand the acceleration mechanism. (paper)

  19. Textural and electronic characteristics of mechanochemically activated composites with nanosilica and activated carbon

    International Nuclear Information System (INIS)

    Gun’ko, V.M.; Zaulychnyy, Ya.V.; Ilkiv, B.I.; Zarko, V.I.; Nychiporuk, Yu.M.; Pakhlov, E.M.; Ptushinskii, Yu.G.; Leboda, R.; Skubiszewska-Zięba, J.

    2011-01-01

    Nanosilicas (A-50, A-300, A-500)/activated carbon (AC, S BET = 1520 m 2 /g) composites were prepared using short-term (5 min) mechanochemical activation (MCA) of powder mixtures in a microbreaker. Smaller silica nanoparticles of A-500 (average diameter d av = 5.5 nm) can more easily penetrate into broad mesopores and macropores of AC microparticles than larger nanoparticles of A-50 (d av = 52.4 nm) or A-300 (d av = 8.1 nm). After MCA of silica/AC, nanopores of non-broken AC nanoparticles remained accessible for adsorbed N 2 molecules. According to ultra-soft X-ray emission spectra (USXES), MCA of silica/AC caused formation of chemical bonds Si-O-C; however, Si-C and Si-Si bonds were practically not formed. A decrease in intensity of OK α band in respect to CK α band of silica/AC composites with diminishing sizes of silica nanoparticles is due to both changes in the surface structure of particles and penetration of a greater number of silica nanoparticles into broad pores of AC microparticles and restriction of penetration depth of exciting electron beam into the AC particles.

  20. Magnetic nanoparticle imaging using multiple electron paramagnetic resonance activation sequences

    International Nuclear Information System (INIS)

    Coene, A.; Dupré, L.; Crevecoeur, G.

    2015-01-01

    Magnetic nanoparticles play an important role in several biomedical applications such as hyperthermia, drug targeting, and disease detection. To realize an effective working of these applications, the spatial distribution of the particles needs to be accurately known, in a non-invasive way. Electron Paramagnetic Resonance (EPR) is a promising and sensitive measurement technique for recovering these distributions. In the conventional approach, EPR is applied with a homogeneous magnetic field. In this paper, we employ different heterogeneous magnetic fields that allow to stabilize the solution of the associated inverse problem and to obtain localized spatial information. A comparison is made between the two approaches and our novel adaptation shows an average increase in reconstruction quality by 5% and is 12 times more robust towards noise. Furthermore, our approach allows to speed up the EPR measurements while still obtaining reconstructions with an improved accuracy and noise robustness compared to homogeneous EPR

  1. New developments in radiation protection instrumentation via active electronic methods

    International Nuclear Information System (INIS)

    Umbarger, C.J.

    1981-01-01

    New developments in electronics and radiation detectors are improving on real-time data acquisition of radiation exposure and contamination conditions. Recent developments in low power circuit designs, hybrid and integrated circuits, and microcomputers have all contributed to smaller and lighter radiation detection instruments that are, at the same time, more sensitive and provide more information (e.g., radioisotope identification) than previous devices. New developments in radiation detectors, such as cadmium telluride, gas scintillation proportional counters, and imaging counters (both charged particle and photon) promise higher sensitivities and expanded uses over present instruments. These developments are being applied in such areas as health physics, waste management, environmental monitoring, in vivo measurements, and nuclear safeguards

  2. Monte Carlo simulations of the Galileo energetic particle detector

    International Nuclear Information System (INIS)

    Jun, I.; Ratliff, J.M.; Garrett, H.B.; McEntire, R.W.

    2002-01-01

    Monte Carlo radiation transport studies have been performed for the Galileo spacecraft energetic particle detector (EPD) in order to study its response to energetic electrons and protons. Three-dimensional Monte Carlo radiation transport codes, MCNP version 4B (for electrons) and MCNPX version 2.2.3 (for protons), were used throughout the study. The results are presented in the form of 'geometric factors' for the high-energy channels studied in this paper: B1, DC2, and DC3 for electrons and B0, DC0, and DC1 for protons. The geometric factor is the energy-dependent detector response function that relates the incident particle fluxes to instrument count rates. The trend of actual data measured by the EPD was successfully reproduced using the geometric factors obtained in this study

  3. Monte Carlo simulations of the Galileo energetic particle detector

    CERN Document Server

    Jun, I; Garrett, H B; McEntire, R W

    2002-01-01

    Monte Carlo radiation transport studies have been performed for the Galileo spacecraft energetic particle detector (EPD) in order to study its response to energetic electrons and protons. Three-dimensional Monte Carlo radiation transport codes, MCNP version 4B (for electrons) and MCNPX version 2.2.3 (for protons), were used throughout the study. The results are presented in the form of 'geometric factors' for the high-energy channels studied in this paper: B1, DC2, and DC3 for electrons and B0, DC0, and DC1 for protons. The geometric factor is the energy-dependent detector response function that relates the incident particle fluxes to instrument count rates. The trend of actual data measured by the EPD was successfully reproduced using the geometric factors obtained in this study.

  4. Heliospheric Observations of Energetic Particles

    Science.gov (United States)

    Summerlin, Errol J.

    2011-01-01

    Heliospheric observations of energetic particles have shown that, on long time averages, a consistent v^-5 power-law index arises even in the absence of transient events. This implies an ubiquitous acceleration process present in the solar wind that is required to generate these power-law tails and maintain them against adiabatic losses and coulomb-collisions which will cool and thermalize the plasma respectively. Though the details of this acceleration process are being debated within the community, most agree that the energy required for these tails comes from fluctuations in the magnetic field which are damped as the energy is transferred to particles. Given this source for the tail, is it then reasonable to assume that the turbulent LISM should give rise to such a power-law tail as well? IBEX observations clearly show a power-law tail of index approximately -5 in energetic neutral atoms. The simplest explanation for the origins of these ENAs are that they are energetic ions which have charge-exchanged with a neutral atom. However, this would imply that energetic ions possess a v^-5 power-law distribution at keV energies at the source of these ENAs. If the source is presumed to be the LISM, it provides additional options for explaining the, so called, IBEX ribbon. This presentation will discuss some of these options as well as potential mechanisms for the generation of a power-law spectrum in the LISM.

  5. About the wind energetics development

    International Nuclear Information System (INIS)

    Strebkov, D.S.; Kharitonov, V.P.; Murugov, V.P.; Sokol'skij, A.K.

    1996-01-01

    The review of wind power energetics state in USA, Europe, Russia is given. The data of EC on wind power plants production in different periods are presented. The directions of scientific-research works with the purpose of increasing the level of wind power industry of Russia corresponding to economics demands were elaborated. (author). 8 refs., 3 tabs

  6. Introduction to global energetic problems

    International Nuclear Information System (INIS)

    Gicquel, R.

    1992-01-01

    This book gives a view on global energetic problems and proposes a thorough economic analysis on principle aspects taken into account: energy supply, depending energy sources and available technologic channels, relationships between macro-economy and energy demand, new size of energy problems (environmental effects, overcosts of renewable energy sources, necessity of an high technologic development...). 38 refs

  7. Electron Tomography Reveals the Active Phase–Support Interaction in Sulfidic Hydroprocessing Catalysts

    NARCIS (Netherlands)

    Eijsbouts, Sonja; Li, Xuang; Juan-Alcaniz, Jana; van den Oetelaar, Leon C A; Bergwerff, Jaap; Loos, Joachim; Carlsson, Anna; Vogt, E.T.C.

    2017-01-01

    Conventional two-dimensional (2D) transmission electron microscopy of sulfidic hydroprocessing catalysts can be deceiving and give the impression that parts of the support are overloaded with active phase. High-angle annular dark field scanning transmission electron microscopy tomography reveals

  8. Metal-Organic Frameworks as Active Materials in Electronic Sensor Devices.

    Science.gov (United States)

    Campbell, Michael G; Dincă, Mircea

    2017-05-12

    In the past decade, advances in electrically conductive metal-organic frameworks (MOFs) and MOF-based electronic devices have created new opportunities for the development of next-generation sensors. Here we review this rapidly-growing field, with a focus on the different types of device configurations that have allowed for the use of MOFs as active components of electronic sensor devices.

  9. Asymmetric activation of the anterior cerebral cortex in recipients of IRECA: Preliminary evidence for the energetic effects of an intention-based biofield treatment modality on human neurophysiology

    NARCIS (Netherlands)

    Pike, C.; Vernon, D.; Hald, L.A.

    2014-01-01

    Neurophysiologic studies of mindfulness link the health benefits of meditation to activation of the left-anterior cerebral cortex. The similarity and functional importance of intention and attentional stance in meditative and biofield therapeutic practices suggest that modulation of recipient

  10. Surface and interface electronic structure: Three year activity report

    International Nuclear Information System (INIS)

    Kevan, S.D.

    1992-01-01

    The 3-year activity report covers surface structure and phonon anomalies (surface reconstruction on W(001) and Mo(001), adsorbate lateral ordering, surface Fermi contours and phonon anomalies on Pt(111) and Pd(001)), adsorbate vibrational damping, charge transfer in momentum space: W(011)-K, surface states and resonances (relativistic effects ampersand computations, surface resonances)

  11. Promoting direct interspecies electron transfer with activated carbon

    DEFF Research Database (Denmark)

    Liu, Fanghua; Rotaru, Amelia-Elena; Shrestha, Pravin M.

    2012-01-01

    Granular activated carbon (GAC) is added to methanogenic digesters to enhance conversion of wastes to methane, but the mechanism(s) for GAC’s stimulatory effect are poorly understood. GAC has high electrical conductivity and thus it was hypothesized that one mechanism for GAC stimulation...

  12. Energetic consumption levels and human development indexes

    International Nuclear Information System (INIS)

    Boa Nova, Antonio Carlos

    1999-01-01

    The article overviews the energetic consumption levels and human development indexes. The human development indexes are described based on the United Nations Development Programme. A comparison between the energetic consumption levels and human development indexes is also presented

  13. Highly n-Type Titanium Oxide as an Electronically Active Support for Platinum in the Catalytic Oxidation of Carbon Monoxide

    KAUST Repository

    Baker, L. Robert; Hervier, Antoine; Seo, Hyungtak; Kennedy, Griffin; Komvopoulos, Kyriakos; Somorjai, Gabor A.

    2011-01-01

    -support interaction is electronic activation of surface adsorbates by charge carriers. Motivated by the goal of using electronic activation to drive nonthermal chemistry, we investigated the ability of the oxide support to mediate charge transfer. We report

  14. Energetically resolved multiple-fluid equilibria of tokamak plasmas

    International Nuclear Information System (INIS)

    Hole, M J; Dennis, G

    2009-01-01

    In many magnetically confined fusion experiments, a significant fraction of the stored energy of the plasma resides in energetic, or non-thermal, particle populations. Despite this, most equilibrium treatments are based on MHD: a single fluid treatment which assumes a Maxwell-Boltzmann distribution function. Detailed magnetic reconstruction based on this treatment ignore the energetic complexity of the plasma and can result in model-data inconsistencies, such as thermal pressure profiles which are inconsistent with the total stored kinetic energy of the plasma. Alternatively, ad hoc corrections to the pressure profile, such as summing the energetic and thermal pressures, have poor theoretical justification. Motivated by this omission, we generalize ideal MHD one step further: we consider multiple quasi-neutral fluids, each in thermal equilibrium and each thermally insulated from each other-no population mixing occurs. Kinetically, such a model may be able to describe the ion or electron distribution function in regions of velocity phase space with a large number of particles, at the expense of more weakly populated phase space, which may have uncharacteristically high temperature and hence pressure. As magnetic equilibrium effects increase with the increase in pressure, our work constitutes an upper limit to the effect of energetic particles. When implemented into an existing solver, FLOW (Guazzotto et al 2004 Phys. Plasmas 11, 604-14), it becomes possible to qualitatively explore the impact of resolving the energetic populations on plasma equilibrium configurations in realistic geometry. Deploying the modified code, FLOW-M, on a high performance spherical torus configuration, we find that the effect of variations of the pressure, poloidal flow and toroidal flow of the energetic populations is qualitatively similar to variations in the background plasma. We also study the robustness of the equilibrium to uncertainties in the current profile and the energetic

  15. The location of energetic compartments affects energetic communication in cardiomyocytes

    Directory of Open Access Journals (Sweden)

    Rikke eBirkedal

    2014-09-01

    Full Text Available The heart relies on accurate regulation of mitochondrial energy supply to match energy demand. The main regulators are Ca2+ and feedback of ADP and Pi. Regulation via feedback has intrigued for decades. First, the heart exhibits a remarkable metabolic stability. Second, diffusion of ADP and other molecules is restricted specifically in heart and red muscle, where a fast feedback is needed the most. To explain the regulation by feedback, compartmentalization must be taken into account. Experiments and theoretical approaches suggest that cardiomyocyte energetic compartmentalization is elaborate with barriers obstructing diffusion in the cytosol and at the level of the mitochondrial outer membrane (MOM. A recent study suggests the barriers are organized in a lattice with dimensions in agreement with those of intracellular structures. Here, we discuss the possible location of these barriers. The more plausible scenario includes a barrier at the level of MOM. Much research has focused on how the permeability of MOM itself is regulated, and the importance of the creatine kinase system to facilitate energetic communication. We hypothesize that at least part of the diffusion restriction at the MOM level is not by MOM itself, but due to the close physical association between the sarcoplasmic reticulum (SR and mitochondria. This will explain why animals with a disabled creatine kinase system exhibit rather mild phenotype modifications. Mitochondria are hubs of energetics, but also ROS production and signaling. The close association between SR and mitochondria may form a diffusion barrier to ADP added outside a permeabilised cardiomyocyte. But in vivo, it is the structural basis for the mitochondrial-SR coupling that is crucial for the regulation of mitochondrial Ca2+-transients to regulate energetics, and for avoiding Ca2+-overload and irreversible opening of the mitochondrial permeability transition pore.

  16. SIMULATION OF ENERGETIC NEUTRAL ATOMS FROM SOLAR ENERGETIC PARTICLES

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Linghua [Institute of Space Physics and Applied Technology, Peking University, Beijing 100871 (China); Li, Gang [Department of Space Science and CSPAR, University of Alabama in Huntsville, Huntsville, AL 35899 (United States); Shih, Albert Y. [Solar Physics Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD 20770 (United States); Lin, Robert P. [Space Sciences Laboratory, University of California, Berkeley, CA 94720-7450 (United States); Wimmer-Schweingruber, Robert F., E-mail: wanglhwang@gmail.com [Institut fuer Experimentelle und Angewandte Physik, University of Kiel, Leibnizstrasse 11, D-24118 Kiel (Germany)

    2014-10-01

    Energetic neutral atoms (ENAs) provide the only way to observe the acceleration site of coronal-mass-ejection-driven (CME-driven) shock-accelerated solar energetic particles (SEPs). In gradual SEP events, energetic protons can charge exchange with the ambient solar wind or interstellar neutrals to become ENAs. Assuming a CME-driven shock with a constant speed of 1800 km s{sup –1} and compression ratio of 3.5, propagating from 1.5 to 40 R{sub S} , we calculate the accelerated SEPs at 5-5000 keV and the resulting ENAs via various charge-exchange interactions. Taking into account the ENA losses in the interplanetary medium, we obtain the flux-time profiles of these solar ENAs reaching 1 AU. We find that the arriving ENAs at energies above ∼100 keV show a sharply peaked flux-time profile, mainly originating from the shock source below 5 R{sub S} , whereas the ENAs below ∼20 keV have a flat-top time profile, mostly originating from the source beyond 10 R{sub S} . Assuming the accelerated protons are effectively trapped downstream of the shock, we can reproduce the STEREO ENA fluence observations at ∼2-5 MeV/nucleon. We also estimate the flux of ENAs coming from the charge exchange of energetic storm protons, accelerated by the fast CME-driven shock near 1 AU, with interstellar hydrogen and helium. Our results suggest that appropriate instrumentation would be able to detect ENAs from SEPs and to even make ENA images of SEPs at energies above ∼10-20 keV.

  17. Electronically Active Impurities in Colloidal Quantum Dot Solids

    KAUST Repository

    Carey, Graham H.

    2014-11-25

    © 2014 American Chemical Society. Colloidal quantum dot films have seen rapid progress as active materials in photodetection, light emission, and photovoltaics. Their processing from the solution phase makes them an attractive option for these applications due to the expected cost reductions associated with liquid-phase material deposition. Colloidally stable nanoparticles capped using long, insulating aliphatic ligands are used to form semiconducting, insoluble films via a solid-state ligand exchange in which the original ligands are replaced with short bifunctional ligands. Here we show that this ligand exchange can have unintended and undesired side effects: a high molecular weight complex can form, containing both lead oleate and the shorter conductive ligand, and this poorly soluble complex can end up embedded within the colloidal quantum dot (CQD) active layer. We further show that, by adding an acidic treatment during film processing, we can break up and wash away these complexes, producing a higher quality CQD solid. The improved material leads to photovoltaic devices with reduced series resistance and enhanced fill factor relative to controls employing previously reported CQD solids. (Figure Presented).

  18. Electronically Active Impurities in Colloidal Quantum Dot Solids

    KAUST Repository

    Carey, Graham H.; Kramer, Illan J.; Kanjanaboos, Pongsakorn; Moreno-Bautista, Gabriel; Voznyy, Oleksandr; Rollny, Lisa; Tang, Joel A.; Hoogland, Sjoerd; Sargent, Edward H.

    2014-01-01

    © 2014 American Chemical Society. Colloidal quantum dot films have seen rapid progress as active materials in photodetection, light emission, and photovoltaics. Their processing from the solution phase makes them an attractive option for these applications due to the expected cost reductions associated with liquid-phase material deposition. Colloidally stable nanoparticles capped using long, insulating aliphatic ligands are used to form semiconducting, insoluble films via a solid-state ligand exchange in which the original ligands are replaced with short bifunctional ligands. Here we show that this ligand exchange can have unintended and undesired side effects: a high molecular weight complex can form, containing both lead oleate and the shorter conductive ligand, and this poorly soluble complex can end up embedded within the colloidal quantum dot (CQD) active layer. We further show that, by adding an acidic treatment during film processing, we can break up and wash away these complexes, producing a higher quality CQD solid. The improved material leads to photovoltaic devices with reduced series resistance and enhanced fill factor relative to controls employing previously reported CQD solids. (Figure Presented).

  19. Electronics

    Science.gov (United States)

    2001-01-01

    International Acer Incorporated, Hsin Chu, Taiwan Aerospace Industrial Development Corporation, Taichung, Taiwan American Institute of Taiwan, Taipei, Taiwan...Singapore and Malaysia .5 - 4 - The largest market for semiconductor products is the high technology consumer electronics industry that consumes up...Singapore, and Malaysia . A new semiconductor facility costs around $3 billion to build and takes about two years to become operational

  20. Solar Energetic Particle Studies with PAMELA

    Science.gov (United States)

    Bravar, U.; Christian, E. R.; deNolfo, Georgia; Ryan, J. M.; Stochaj, S.

    2011-01-01

    The origin of the high-energy solar energetic particles (SEPs) may conceivably be found in composition signatures that reflect the elemental abundances of the low corona and chromosphere vs. the high corona and solar wind. The presence of secondaries, such as neutrons and positrons, could indicate a low coronal origin of these particles. Velocity dispersion of different species and over a wide energy range can be used to determine energetic particle release times at the Sun. Together with multi-wavelength imaging, in- situ observations of a variety of species, and coverage over a wide energy range provide a critical tool in identifying the origin of SEPs, understanding the evolution of these events within the context of solar active regions, and constraining the acceleration mechanisms at play. The Payload for Antimatter Matter Exploration and Light-nuclei Astrophysics (PAMELA)instrument, successfully launched in 2006 and expected to remain operational until at least the beginning of 2012, measures energetic particles in the same energy range as ground-based neutron monitors, and lower energies as well. It thus bridges the gap between low energy in-situ observations and ground-based Ground Level Enhancements (GLE) observations. It can measure the charge (up to Z=6) and atomic number of the detected particles, and it can identify and measure positrons and detect neutrons-an unprecedented array of data channels that we can bring to bear on the origin of high-energy SEPs. We present prelimiary results on the for the 2006 December 13 solar flare and GLE and the 2011 March 21 solar flare, both registering proton and helium enhancements in PAMELA. Together with multi- spacecraft contextual data and modeling, we discuss the PAMELA results in the context of the different acceleration mechanisms at play.

  1. Prompt Loss of Energetic Ions during Early Neutral Beam Injection in the National Spherical Torus Experiment

    International Nuclear Information System (INIS)

    Medley, S.S.; Darrow, D.S.; Liu, D.; Roquemore, A.L.

    2005-01-01

    Early neutral-beam injection is used in the National Spherical Torus Experiment (NSTX) to heat the electrons and slow current penetration which keeps q(0) elevated to avoid deleterious MHD activity and at the same time reduces Ohmic flux consumption, all of which aids long-pulse operation. However, the low plasma current (I p ∼ 0.5 MA) and electron density (n e ∼ 1 x 10 13 cm -3 ) attending early injection lead to elevated orbit and shine through losses. The inherent orbit losses are aggravated by large excursions in the outer gap width during current ramp-up. An investigation of this behavior using various energetic particle diagnostics on NSTX and TRANSP code analysis is presented

  2. Very energetic photons at HERA

    International Nuclear Information System (INIS)

    Bawa, A.C.; Krawczyk, M.

    1991-01-01

    We show that every energetic photons in the backward direction can be produced in deep inelastic Compton scattering at HERA. Assuming a fixed energy of 9 GeV for the initial photons and 820 GeV for the protons a high rate is found for the production of final photons with a transverse momentum equal to 5 GeV/c and energy between 40 GeV and 300 GeV. These energetic photons arise mainly from the scattering of the soft gluonic constituents of the initial photon with quarks from the proton. They are produced in the backward direction in coincidence with a photon beam jet of energy ∝ 9 GeV in the forward direction. (orig.)

  3. The energetic significance of cooking.

    Science.gov (United States)

    Carmody, Rachel N; Wrangham, Richard W

    2009-10-01

    While cooking has long been argued to improve the diet, the nature of the improvement has not been well defined. As a result, the evolutionary significance of cooking has variously been proposed as being substantial or relatively trivial. In this paper, we evaluate the hypothesis that an important and consistent effect of cooking food is a rise in its net energy value. The pathways by which cooking influences net energy value differ for starch, protein, and lipid, and we therefore consider plant and animal foods separately. Evidence of compromised physiological performance among individuals on raw diets supports the hypothesis that cooked diets tend to provide energy. Mechanisms contributing to energy being gained from cooking include increased digestibility of starch and protein, reduced costs of digestion for cooked versus raw meat, and reduced energetic costs of detoxification and defence against pathogens. If cooking consistently improves the energetic value of foods through such mechanisms, its evolutionary impact depends partly on the relative energetic benefits of non-thermal processing methods used prior to cooking. We suggest that if non-thermal processing methods such as pounding were used by Lower Palaeolithic Homo, they likely provided an important increase in energy gain over unprocessed raw diets. However, cooking has critical effects not easily achievable by non-thermal processing, including the relatively complete gelatinisation of starch, efficient denaturing of proteins, and killing of food borne pathogens. This means that however sophisticated the non-thermal processing methods were, cooking would have conferred incremental energetic benefits. While much remains to be discovered, we conclude that the adoption of cooking would have led to an important rise in energy availability. For this reason, we predict that cooking had substantial evolutionary significance.

  4. Electron beam injection during active experiments. 2. Collisional effects

    International Nuclear Information System (INIS)

    Winglee, R.M.

    1990-01-01

    During active beam experiments the presence of high neutral densities at low altitudes and/or during thruster firings has been observed to modify the spacecraft charging and the properties of the beam. Two-dimensional (three velocity) electromagnetic particle simulations with ionizing collisions incorporated are used to investigate the modification of the beam-plasma interaction as the neutral density is increased. It is shown that when the spacecraft is uniformly immersed in a neutral cloud, most of the ionization is produced by direct ionization by the beam and its secondaries, rather than via vehicle-induced or wave-ineuced ionization for the neutral densities considered. This ionization enhances the return current into the spacecraft with the spacecraft potential being reduced well below the beam energy whent he collison period is shorter than the spacecraft charging time. Neutral densities of about 10 11 -10 12 cm -3 are required to produce this reduction in the spacecraft potential for typical ionospheric and beam parameters. At these densities, the beam is able to propagate away from the spacecraft with little distortion except in the case of thruster firings where the beam can be subject to large space-charge oscillations near the boundaries of the neutral cloud. The ionization of neutrals in the beam region also modifies the wave emissions and spatial profile of return currents into the spacecraft, both of which tend to become localized to the beam region in high neutral densities

  5. Electron microscopy studies of activation mechanisms in hydrotreating catalysis

    DEFF Research Database (Denmark)

    Dahl-Petersen, Christian

    The aim of this work is to remedy the limited fundamental insight that exists in terms of the activation and formation of hydrotreating catalysts utilized in industrial oil refining of crude oil. This is done through numerous studies of the conversion of industrially relevant molybdenum oxide...... larger amount of formed MoS2. MoS2 forms in one of two conformations of the two-dimensional atomic structure that is either in an orientation parallel or perpendicular to the nanoparticle surface. Both the initial growth of MoS2 and the subsequent formation of multi-layered structures is addressed....... This shows that initial growth tends to form an apparent bond between the MoO2 surface and the MoS2 edge and that the layer size increases through coalescence. For multi-layered structures, it is found that MoS2 layers grow through a layer-under-layer mechanism, where defects in the outer layers enable...

  6. Defects in the Expression of Chloroplast Proteins Leads to H2O2 Accumulation and Activation of Cyclic Electron Flow around Photosystem I.

    Science.gov (United States)

    Strand, Deserah D; Livingston, Aaron K; Satoh-Cruz, Mio; Koepke, Tyson; Enlow, Heather M; Fisher, Nicholas; Froehlich, John E; Cruz, Jeffrey A; Minhas, Deepika; Hixson, Kim K; Kohzuma, Kaori; Lipton, Mary; Dhingra, Amit; Kramer, David M

    2016-01-01

    We describe a new member of the class of mutants in Arabidopsis exhibiting high rates of cyclic electron flow around photosystem I (CEF), a light-driven process that produces ATP but not NADPH. High cyclic electron flow 2 ( hcef2 ) shows strongly increased CEF activity through the NADPH dehydrogenase complex (NDH), accompanied by increases in thylakoid proton motive force ( pmf ), activation of the photoprotective q E response, and the accumulation of H 2 O 2 . Surprisingly, hcef2 was mapped to a non-sense mutation in the TADA1 (tRNA adenosine deaminase arginine) locus, coding for a plastid targeted tRNA editing enzyme required for efficient codon recognition. Comparison of protein content from representative thylakoid complexes, the cytochrome bf complex, and the ATP synthase, suggests that inefficient translation of hcef2 leads to compromised complex assembly or stability leading to alterations in stoichiometries of major thylakoid complexes as well as their constituent subunits. Altered subunit stoichiometries for photosystem I, ratios and properties of cytochrome bf hemes, and the decay kinetics of the flash-induced thylakoid electric field suggest that these defect lead to accumulation of H 2 O 2 in hcef2 , which we have previously shown leads to activation of NDH-related CEF. We observed similar increases in CEF, as well as increases in H 2 O 2 accumulation, in other translation defective mutants. This suggests that loss of coordination in plastid protein levels lead to imbalances in photosynthetic energy balance that leads to an increase in CEF. These results taken together with a large body of previous observations, support a general model in which processes that lead to imbalances in chloroplast energetics result in the production of H 2 O 2 , which in turn activates CEF. This activation could be from either H 2 O 2 acting as a redox signal, or by a secondary effect from H 2 O 2 inducing a deficit in ATP.

  7. Life cycles of energetic systems

    International Nuclear Information System (INIS)

    Adnot, Jerome; Marchio, Dominique; Riviere, Philippe; Duplessis, B.; Rabl, A.; Glachant, M.; Aggeri, F.; Benoist, A.; Teulon, H.; Daude, J.

    2012-01-01

    This collective publication aims at being a course for students in engineering of energetic systems, i.e. at learning how to decide to accept or discard a project, to select the most efficient system, to select the optimal system, to select the optimal combination of systems, and to classify independent systems. Thus, it presents methods to analyse system life cycle from an energetic, economic and environmental point of view, describes how to develop an approach to the eco-design of an energy consuming product, how to understand the importance of hypotheses behind abundant and often contradicting publicised results, and to be able to criticise or to put in perspective one's own analysis. The first chapters thus recall some aspects of economic calculation, introduce the assessment of investment and exploitation costs of energetic systems, describe how to assess and internalise environmental costs, present the territorial carbon assessment, discuss the use of the life cycle assessment, and address the issue of environmental management at a product scale. The second part proposes various case studies: an optimal fleet of thermal production of electric power, the eco-design of a refrigerator, the economic and environmental assessment of wind farms

  8. Electronic dosimetry and neutron metrology by CMOS active pixel sensor

    International Nuclear Information System (INIS)

    Vanstalle, M.

    2011-01-01

    This work aims at demonstrating the possibility to use active pixel sensors as operational neutron dosemeters. To do so, the sensor that has been used has to be γ-transparent and to be able to detect neutrons on a wide energy range with a high detection efficiency. The response of the device, made of the CMOS sensor MIMOSA-5 and a converter in front of the sensor (polyethylene for fast neutron detection and 10 B for thermal neutron detection), has been compared with Monte Carlo simulations carried out with MCNPX and GEANT4. These codes have been before-hand validated to check they can be used properly for our application. Experiments to characterize the sensor have been performed at IPHC and at IRSN/LMDN (Cadarache). The results of the sensor irradiation to photon sources and mixed field ( 241 AmBe source) show the γ-transparency of the sensor by applying an appropriate threshold on the deposited energy (around 100 keV). The associated detection efficiency is satisfactory with a value of 10 -3 , in good agreement with MCNPX and GEANT4. Other features of the device have been tested with the same source, like the angular response. The last part of this work deals with the detection of thermal neutrons (eV-neutrons). Assays have been done in Cadarache (IRSN) with a 252 Cf source moderated with heavy water (with and without cadmium shell). Results asserted a very high detection efficiency (up to 6*10 -3 for a pure 10 B converter) in good agreement with GEANT4. (author)

  9. Nuclear energetics as environmentally affable source - present and and future

    International Nuclear Information System (INIS)

    Suchomel, J.

    2002-01-01

    In this paper the situation in nuclear energetics in the world in 2000 year is presented. Climatic changes initiated by burning of the fossil fuels an influence of nuclear energetics are discussed. Author informs that European Union and U.S.A. supports developing of nuclear energetics. Nuclear phobia from radiation risk of some inhabitants is compared with risks of other man activities. Possibilities of the electricity production by alternative sources are compared. Liability of the Slovak Republic for decommissioning of two reactor of the V-1 Jaslovske Bohunice NPP in 2006 and 2008, which is compared with the Program of safety improvement of these reactors are discussed. Author and Slovak Nuclear Society accept gladly the suggestion of government of the Slovak Republic that they reassess this liability. The best alternative for decommissioned Jaslovske Bohunice NPP will be the completion of the 3 rd and 4 th blocks of the Mochovce NPP

  10. THEMIS Observations of the Magnetopause Electron Diffusion Region: Large Amplitude Waves and Heated Electrons

    Science.gov (United States)

    Tang, Xiangwei; Cattell, Cynthia; Dombeck, John; Dai, Lei; Wilson, Lynn B. III; Breneman, Aaron; Hupack, Adam

    2013-01-01

    We present the first observations of large amplitude waves in a well-defined electron diffusion region based on the criteria described by Scudder et al at the subsolar magnetopause using data from one Time History of Events and Macroscale Interactions during Substorms (THEMIS) satellite. These waves identified as whistler mode waves, electrostatic solitary waves, lower hybrid waves, and electrostatic electron cyclotron waves, are observed in the same 12 s waveform capture and in association with signatures of active magnetic reconnection. The large amplitude waves in the electron diffusion region are coincident with abrupt increases in electron parallel temperature suggesting strong wave heating. The whistler mode waves, which are at the electron scale and which enable us to probe electron dynamics in the diffusion region were analyzed in detail. The energetic electrons (approx. 30 keV) within the electron diffusion region have anisotropic distributions with T(sub e(right angle))/T(sub e(parallel)) > 1 that may provide the free energy for the whistler mode waves. The energetic anisotropic electrons may be produced during the reconnection process. The whistler mode waves propagate away from the center of the "X-line" along magnetic field lines, suggesting that the electron diffusion region is a possible source region of the whistler mode waves.

  11. Energetics of charged metal clusters containing vacancies

    Science.gov (United States)

    Pogosov, Valentin V.; Reva, Vitalii I.

    2018-01-01

    We study theoretically large metal clusters containing vacancies. We propose an approach, which combines the Kohn-Sham results for monovacancy in a bulk of metal and analytical expansions in small parameters cv (relative concentration of vacancies) and RN,v -1, RN ,v being cluster radii. We obtain expressions of the ionization potential and electron affinity in the form of corrections to electron work function, which require only the characteristics of 3D defect-free metal. The Kohn-Sham method is used to calculate the electron profiles, ionization potential, electron affinity, electrical capacitance; dissociation, cohesion, and monovacancy-formation energies of the small perfect clusters NaN, MgN, AlN (N ≤ 270) and the clusters containing a monovacancy (N ≥ 12) in the stabilized-jellium model. The quantum-sized dependences for monovacancy-formation energies are calculated for the Schottky scenario and the "bubble blowing" scenario, and their asymptotic behavior is also determined. It is shown that the asymptotical behaviors of size dependences for these two mechanisms differ from each other and weakly depend on the number of atoms in the cluster. The contribution of monovacancy to energetics of charged clusters and the size dependences of their characteristics and asymptotics are discussed. It is shown that the difference between the characteristics for the neutral and charged clusters is entirely determined by size dependences of ionization potential and electron affinity. Obtained analytical dependences may be useful for the analysis of the results of photoionization experiments and for the estimation of the size dependences of the vacancy concentration including the vicinity of the melting point.

  12. Activity of flavonoids through λ sub max and electron cross-section

    International Nuclear Information System (INIS)

    Murthy, V.R.; Sreenivasulu, M.

    1997-01-01

    Flavonoids are widespread groups of natural constituents and present in the drugs in the form of mono or diglycosides. Being physiologically active, flavonoids are important in the field of pharmacological and clinical applications. Not many physical properties of flavonoids have been studied so far excepting UV and NMR studies. This paper deals with the evaluation of electron ionization cross section through λ sub max, a parameter available from UV studies. Electron ionization cross section was primarily conceived to be of use in radiation chemical data, mass spectroscopic and thermodynamic studies. But later attempts to correlate electron ionization cross-section with structural and related parameters prompted the authors to derive an explicit expression relating λ sub max and electron ionization cross-section (Q). The application of this method to correlate Q through λ sub max and interpret the results in terms of chemical activity are discussed

  13. Energetics of dislocation nucleation under a nanoindenter

    International Nuclear Information System (INIS)

    Zhang Chuanli; Xu Guanshui

    2005-01-01

    We present an analysis of dislocation nucleation under an idealized nanoindenter based on the variational boundary integral formulation of the Peierls-Nabarro dislocation model. By solving the embryonic dislocation profiles, corresponding to the relative displacements between the two adjacent atomic layers along the slip plane, we have determined the critical conditions for athermal dislocation nucleation as well as the activation energies required to thermally activate embryonic dislocations from their stable to unstable saddle point configurations. The effect of the size of the indenter on the energetics of dislocation nucleation is quantitatively characterized. The result is compared with a simplified analysis based on the application of the Rice model for dislocation nucleation at a crack tip

  14. Energetics of dislocation nucleation under a nanoindenter

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Chuanli [College of Mechanical Engineering, Yangtze University, Jingzhou, Hubei 434023 (China); Department of Mechanical Engineering, University of California, Riverside, CA 92521 (United States); Xu Guanshui [Department of Mechanical Engineering, University of California, Riverside, CA 92521 (United States)]. E-mail: guanshui.xu@ucr.edu

    2005-07-25

    We present an analysis of dislocation nucleation under an idealized nanoindenter based on the variational boundary integral formulation of the Peierls-Nabarro dislocation model. By solving the embryonic dislocation profiles, corresponding to the relative displacements between the two adjacent atomic layers along the slip plane, we have determined the critical conditions for athermal dislocation nucleation as well as the activation energies required to thermally activate embryonic dislocations from their stable to unstable saddle point configurations. The effect of the size of the indenter on the energetics of dislocation nucleation is quantitatively characterized. The result is compared with a simplified analysis based on the application of the Rice model for dislocation nucleation at a crack tip.

  15. Electron transfer activation of a second water channel for proton transport in [FeFe]-hydrogenase

    Energy Technology Data Exchange (ETDEWEB)

    Sode, Olaseni; Voth, Gregory A., E-mail: gavoth@uchicago.edu [Department of Chemistry, James Franck Institute, Institute for Biophysical Dynamics, Computation Institute, The University of Chicago, Chicago, Illinois 60637, USA and Computing, Environment and Life Sciences, Argonne National Laboratory, Argonne, Illinois 60439 (United States)

    2014-12-14

    Hydrogenase enzymes are important because they can reversibly catalyze the production of molecular hydrogen. Proton transport mechanisms have been previously studied in residue pathways that lead to the active site of the enzyme via residues Cys299 and Ser319. The importance of this pathway and these residues has been previously exhibited through site-specific mutations, which were shown to interrupt the enzyme activity. It has been shown recently that a separate water channel (WC2) is coupled with electron transport to the active site of the [FeFe]-hydrogenase. The water-mediated proton transport mechanisms of the enzyme in different electronic states have been studied using the multistate empirical valence bond reactive molecular dynamics method, in order to understand any role WC2 may have in facilitating the residue pathway in bringing an additional proton to the enzyme active site. In a single electronic state A{sup 2−}, a water wire was formed through which protons can be transported with a low free energy barrier. The remaining electronic states were shown, however, to be highly unfavorable to proton transport in WC2. A double amino acid substitution is predicted to obstruct proton transport in electronic state A{sup 2-} by closing a cavity that could otherwise fill with water near the proximal Fe of the active site.

  16. Electron transfer activation of a second water channel for proton transport in [FeFe]-hydrogenase

    International Nuclear Information System (INIS)

    Sode, Olaseni; Voth, Gregory A.

    2014-01-01

    Hydrogenase enzymes are important because they can reversibly catalyze the production of molecular hydrogen. Proton transport mechanisms have been previously studied in residue pathways that lead to the active site of the enzyme via residues Cys299 and Ser319. The importance of this pathway and these residues has been previously exhibited through site-specific mutations, which were shown to interrupt the enzyme activity. It has been shown recently that a separate water channel (WC2) is coupled with electron transport to the active site of the [FeFe]-hydrogenase. The water-mediated proton transport mechanisms of the enzyme in different electronic states have been studied using the multistate empirical valence bond reactive molecular dynamics method, in order to understand any role WC2 may have in facilitating the residue pathway in bringing an additional proton to the enzyme active site. In a single electronic state A 2− , a water wire was formed through which protons can be transported with a low free energy barrier. The remaining electronic states were shown, however, to be highly unfavorable to proton transport in WC2. A double amino acid substitution is predicted to obstruct proton transport in electronic state A 2- by closing a cavity that could otherwise fill with water near the proximal Fe of the active site

  17. Special section containing papers presented at the 13th IAEA Technical Meeting on Energetic Particles in Magnetic Confinement Systems (Beijing, China, 17-20 September 2013) Special section containing papers presented at the 13th IAEA Technical Meeting on Energetic Particles in Magnetic Confinement Systems (Beijing, China, 17-20 September 2013)

    Science.gov (United States)

    Lin, Z.

    2014-10-01

    , abstracts of all papers, and slides of oral presentations are available at the conference website:www.phy.pku.edu.cn/fsc/w18419.jsp As a measure of the breadth in current research activities, a wide range of topics in energetic particle physics were covered in the meeting program, including dynamics of various Alfvén eigenmodes and energetic particle modes, energetic particle transport, energetic particle effects on magnetohydrodynamic (MHD) modes, runaway electrons, and diagnostics of energetic particles and neutrons. Energetic particle experiments were reported on tokamaks, stellarators, spherical tori, reversed field pinches, and linear devices. Most of the papers have direct comparisons between experimental data and simulation results, a very healthy trend in the research of energetic particle physics. As an indication for the depth in current research activities and possible future directions in energetic particle physics, some exciting progress reported at the meeting is highlighted here. The 3D fields of resonant magnetic perturbations (RMP) for controlling edge localized modes (ELM) are found to drive significant ripple loss of fast ions in DIII-D and ASDEX-U experiments. Similar loss is predicted for ITER RMP fields in the vacuum approximation. Fortunately, plasma response to RMP fields is found by the simulation to reduce the loss of fast ions and α-particles to a benign level. These results call for more accurate measurements and more reliable modeling of the plasma response to RMP fields in existing tokamak experiments and in future ITER experiments. Interesting progress on energetic particle transport by Alfvén eigenmodes was made in reduced 1D models based on the critical gradients model, in which energetic particle pressure gradients are relaxed to the local threshold of Alfvén eigenmode stability. Some experimental support for the critical gradient model was reported in DIII-D off-axis neutral beam injection (NBI) experiments, in which the fast

  18. A comparison of energetic ions in the plasma depletion layer and the quasi-parallel magnetosheath

    Science.gov (United States)

    Fuselier, Stephen A.

    1994-01-01

    Energetic ion spectra measured by the Active Magnetospheric Particle Tracer Explorers/Charge Composition Explorer (AMPTE/CCE) downstream from the Earth's quasi-parallel bow shock (in the quasi-parallel magnetosheath) and in the plasma depletion layer are compared. In the latter region, energetic ions are from a single source, leakage of magnetospheric ions across the magnetopause and into the plasma depletion layer. In the former region, both the magnetospheric source and shock acceleration of the thermal solar wind population at the quasi-parallel shock can contribute to the energetic ion spectra. The relative strengths of these two energetic ion sources are determined through the comparison of spectra from the two regions. It is found that magnetospheric leakage can provide an upper limit of 35% of the total energetic H(+) population in the quasi-parallel magnetosheath near the magnetopause in the energy range from approximately 10 to approximately 80 keV/e and substantially less than this limit for the energetic He(2+) population. The rest of the energetic H(+) population and nearly all of the energetic He(2+) population are accelerated out of the thermal solar wind population through shock acceleration processes. By comparing the energetic and thermal He(2+) and H(+) populations in the quasi-parallel magnetosheath, it is found that the quasi-parallel bow shock is 2 to 3 times more efficient at accelerating He(2+) than H(+). This result is consistent with previous estimates from shock acceleration theory and simulati ons.

  19. Relationship between Antifungal Activity against Candida albicans and Electron Parameters of Selected N-Heterocyclic Thioamides

    Science.gov (United States)

    Stachowicz, Jadwiga; Krajewska-Kułak, Elżbieta; Łukaszuk, Cecylia; Niewiadomy, A.

    2014-01-01

    Due to the increasing demand for new pharmaceuticals showing biological activity against pathogenic microorganisms, there is increasing search for new compounds with predicted biological activity. Variously substituted thioamide derivatives with 1.3 and 1.2 ring of thiazole and 1,3,4-thiadiazole, as well as pyrazole were assessed for their activity against Candida albicans. Activity of majority of tested thioamides was larger as compared with that of the reference drugs. The electron parameters of obtained N-heterocyclic thioamides were determined and dependencies on their biological activity against Candida albicans were studied. The best electron compliance of produced bindings with the activity against Candida albicans was observed for the derivatives containing 1,3,4-thiadiazole ring. PMID:25284926

  20. Cathodoluminescence-activated nanoimaging: noninvasive near-field optical microscopy in an electron microscope.

    Science.gov (United States)

    Bischak, Connor G; Hetherington, Craig L; Wang, Zhe; Precht, Jake T; Kaz, David M; Schlom, Darrell G; Ginsberg, Naomi S

    2015-05-13

    We demonstrate a new nanoimaging platform in which optical excitations generated by a low-energy electron beam in an ultrathin scintillator are used as a noninvasive, near-field optical scanning probe of an underlying sample. We obtain optical images of Al nanostructures with 46 nm resolution and validate the noninvasiveness of this approach by imaging a conjugated polymer film otherwise incompatible with electron microscopy due to electron-induced damage. The high resolution, speed, and noninvasiveness of this "cathodoluminescence-activated" platform also show promise for super-resolution bioimaging.

  1. Defects in the Expression of Chloroplast Proteins Leads to H2O2 Accumulation and Activation of Cyclic Electron Flow around Photosystem I

    Energy Technology Data Exchange (ETDEWEB)

    Strand, Deserah D.; Livingston, Aaron K.; Satoh-Cruz, Mio; Koepke, Tyson; Enlow, Heather M.; Fisher, Nicholas; Froehlich, John E.; Cruz, Jeffrey A.; Minhas, Deepika; Hixson, Kim K.; Kohzuma, Kaori; Lipton, Mary; Dhingra, Amit; Kramer, David M.

    2017-01-13

    We describe a new member of the class of mutants in Arabidopsis exhibiting high rates of cyclic electron flow around photosystem I (CEF), a light-driven process that produces ATP but not NADPH. High cyclic electron flow 2 (hcef2) shows strongly increased CEF activity through the NADPH dehydrogenase complex (NDH), accompanied by increases in thylakoid proton motive force (pmf), activation of the photoprotective qE response, and the accumulation of H2O2 . Surprisingly, hcef2 was mapped to a nonsense mutation in the TADA1 (tRNA adenosine deaminase arginine) locus, coding for a plastid targeted tRNA editing enzyme required for efficient codon recognition. Comparison of protein content from representative thylakoid complexes, the cytochrome bf complex and the ATP synthase, suggests that inefficient translation of hcef2 leads to compromised complex assembly or stability leading to alterations in stoichiometries of major thylakoid complexes as well as their constituent subunits. Altered subunit stoichiometries for photosystem I, ratios and properties of cytochrome bf hemes, and the decay kinetics of the flash induced thylakoid electric field suggest that these defect lead to accumulation of H2O2 in hcef2, which we have previously shown leads to activation of NDHrelated CEF. We observed similar increases in CEF and H2O2 accumulation in other translation defective mutants, suggesting that loss of coordination in plastid protein levels lead to imbalances in the photosynthetic energy balance that leads to increased CEF. These results, together with a large body of previous observations, support a general model in which processes that imbalances in chloroplast energetics result in the production of H2O2 , which activates CEF, either as a redox signal or by inducing deficits in ATP levels.

  2. Los Alamos energetic particle sensor systems at geostationary orbit

    International Nuclear Information System (INIS)

    Baker, D.N.; Aiello, W.; Asbridge, J.R.; Belian, R.D.; Higbie, P.R.; Klebesadel, R.W.; Laros, J.G.; Tech, E.R.

    1985-01-01

    The Los Alamos National Laboratory has provided energetic particle sensors for a variety of spacecraft at the geostationary orbit (36,000 km altitude). The sensor system called the Charged Particle Analyzer (CPA) consists of four separate subsystems. The LoE and HiE subsystems measure electrons in the energy ranges 30 to 300 keV and 200 to 2000 keV, respectively. The LoP and HiP subsystems measure ions in the ranges 100 to 600 keV and 0.40 to 150 MeV, respectively. A separate sensor system called the spectrometer for energetic electrons (SEE) measures very high-energy electrons (2 to 15 MeV) using advanced scintillator design. In this paper we describe the relationship of operational anomalies and spacecraft upsets to the directly measured energetic particle environments at 6.6 R/sub E/. We also compare and contrast the CPA and SEE instrument design characteristics with the next generation of Los Alamos instruments to be flown at geostationary altitudes

  3. Electron-topological investigation of the structure-antitumor activity relationship of thiosemicarbazone derivatives.

    Science.gov (United States)

    Dimoglo, A S; Chumakov, Y M; Dobrova, B N; Saracoglu, M

    1997-04-01

    In the frameworks of the electron-topological method (ETM) the structure-antitumor activity relationship was investigated for a series of thiosemicarbazone derivatives. The series included 70 compounds. Conformational analysis and quantum-chemical calculations were carried out for each compound. The revealed activity feature showed a satisfactory description of the class of active compounds according to two different parameters P and alpha estimating the probabilities of the feature realization in the class of active compounds (they are equal to 0.94 and 0.86, correspondingly). The results of testing demonstrated the high ability of ETM in predicting the activity investigated.

  4. Correlation between biological activity and electron transferring of bovine liver catalase: Osmolytes effects

    International Nuclear Information System (INIS)

    Tehrani, H. Sepasi; Moosavi-Movahedi, A.A.; Ghourchian, H.

    2013-01-01

    Highlights: • Proline increases ET in Bovine Liver Catalase (BLC) whereas histidine decreases it. • Proline also increased the biological activity, whereas histidine decreased it. • Electron transferring and biological activity for BLC are directly correlated. • Proline causes favorable ET for BLC shown by positive E 1/2 (E°′) and negative ΔG. • Histidine makes ET unfavorable for BLC, manifested by E 1/2 (E°′) 0. -- Abstract: Catalase is a crucial antioxidant enzyme that protects life against detrimental effects of H 2 O 2 by disproportionating it into water and molecular oxygen. Effect of proline as a compatible and histidine as a non compatible osmolyte on the electron transferring and midpoint potential of catalase has been investigated. Proline increases the midpoint potential (ΔE m > 0), therefore causing the ΔG ET to be less positive and making the electron transfer reaction more facile whereas histidine decreases the E m (ΔE m ET , thereby rendering the electron transfer reaction less efficient. These results indicate the inhibitory effect of histidine evident by a −37% decrease in the cathodic peak current compared to 16% increase in the case of proline indicative of activation. The insight paves the tedious way towards our ultimate goal of elucidating a correlation between biological activity and electron transferring

  5. Effect of electron-beam irradiation on the antioxidant activity of extracts from Citrus unshiu pomaces

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jong-Wan [Department of Food Science and Biotechnology, Kyungnam University, Masan 631-701 (Korea, Republic of); Lee, Byung Cheol [Laboratory for Quantum Optics, Korea Atomic Energy Research Institute, Daejeon 305-600 (Korea, Republic of); Lee, Jong-Hwa [School of Bioresource Sciences, Andong National University, Andong 760-749 (Korea, Republic of); Nam, Ki-Chang [Chemistry and Biotechnology Examinations Bureau, Korean Intellectual Property Office, Daejeon 302-701 (Korea, Republic of); Lee, Seung-Cheol [Department of Food Science and Biotechnology, Kyungnam University, Masan 631-701 (Korea, Republic of)], E-mail: sclee@kyungnam.ac.kr

    2008-01-15

    After electron-beam irradiation of citrus pomaces (CP), the total phenolic content (TPC), radical scavenging activity (RSA), and reducing power (RP) were evaluated. When CP were irradiated at 37.9 kGy; the TPC, RSA and RP of water extract of CP increased from 6543.2 to 7405.4 {mu}M, 37.6% to 52.9%, and 0.64 to 0.90, respectively, compared with the non-irradiated control. The results indicate that the electron-beam irradiation can be an efficient process for increasing the antioxidant activity of CP.

  6. Energetics of the built environment

    Energy Technology Data Exchange (ETDEWEB)

    Yeang, K

    1974-07-01

    Energetics, the study of energy transformations within ecosystems, provide a useful framework for examining the relationships between the built environment (a manmade ecosystem) and the natural environment. Values are provided for using energy indices in modeling, comparing design alternatives, improving designed systems, conserving nonrenewable resources, comparing impacts, and studying energy utilization patterns as a whole. The accounting of the energy cost of a proposed project would provide additional criteria for evaluating the impact of human developments on the natural environment. (3 diagrams, 12 tables)

  7. Energetic particles in the heliosphere

    CERN Document Server

    Simnett, George M

    2017-01-01

    This monograph traces the development of our understanding of how and where energetic particles are accelerated in the heliosphere and how they may reach the Earth. Detailed data sets are presented which address these topics. The bulk of the observations are from spacecraft in or near the ecliptic plane. It is timely to present this subject now that Voyager-1 has entered the true interstellar medium. Since it seems unlikely that there will be a follow-on to the Voyager programme any time soon, the data we already have regarding the outer heliosphere are not going to be enhanced for at least 40 years.

  8. Thermal-spectrum recriticality energetics

    International Nuclear Information System (INIS)

    Schwinkendorf, K.N.

    1993-12-01

    Large computer codes have been created in the past to predict the energy release in hypothetical core disruptive accidents (CDA), postulated to occur in liquid metal reactors (LMR). These codes, such as SIMMER, are highly specific to LMR designs. More recent attention has focused on thermal-spectrum criticality accidents, such as for fuel storage basins and waste tanks containing fissile material. This paper resents results from recent one-dimensional kinetics simulations, performed for a recriticality accident in a thermal spectrum. Reactivity insertion rates generally are smaller than in LMR CDAs, and the energetics generally are more benign. Parametric variation of input was performed, including reactivity insertion and initial temperature

  9. Structural, energetic and electrical properties of boron nitride nanotubes interacting with DMMP chemical agent

    Energy Technology Data Exchange (ETDEWEB)

    Ganji, M. Darvish, E-mail: ganji_md@yahoo.com [Nanotechnology Research Institute, Faculty of Chemical Engineering, Babol Noshirvani University of Technology, Babol (Iran, Islamic Republic of); Gholian, M.; Mohammadzadeh, S. [Department of Chemistry, Qaemshahr Branch, Islamic Azad University, Qaemshahr (Iran, Islamic Republic of)

    2014-09-30

    Highlights: • ab initio DFT calculations were used for interaction of DMMP with BNNTs. • Full structural optimization was performed for several possible active sites. • Electronic structure of the energetically favorable complexes was analyzed. • The stability of the most stable complex was evaluated at ambient condition. • First-principles calculations showed that DMMP is strongly bound to the small diameter BNNTs. - Abstract: The adsorption of DMMP as an intoxicating chemical warfare agent onto the boron nitride nanotube has been investigated by using density functional theory calculations. Several active sites were considered for both interacting systems and full structural optimization was performed to accurately find the energetically favorable state. It is found that DMMP molecule prefers to be adsorbed strongly on the top site above the B atom of a (5, 0) BNNT with a binding energy of about −103.24 kJ mol{sup −1} and an O–B binding distance of 1.641 Å. We have performed a comparative investigation of BNNTs with different diameters and the results indicate that the DMMP adsorption ability for the side wall of the tubes significantly decreases for higher diameters BNNTs. Furthermore, the adsorption properties of DMMP molecule onto the BNNT have been investigated using the ab initio MD simulation at room temperature. Our result showed that BNNTs facilitates the DMMP detection at ambient conditions for practical applications.

  10. Localization of xanthine oxidoreductase activity using the tissue protectant polyvinyl alcohol and final electron acceptor Tetranitro BT

    NARCIS (Netherlands)

    Kooij, A.; Frederiks, W. M.; Gossrau, R.; van Noorden, C. J.

    1991-01-01

    We have detected xanthine oxidoreductase activity in unfixed cryostat sections of rat and chicken liver, rat duodenum, and bovine mammary gland using the tissue protectant polyvinyl alcohol, the electron carrier 1-methoxyphenazine methosulfate, the final electron acceptor Tetranitro BT, and

  11. Adherence to active play and electronic media guidelines in preschool children: gender and parental education considerations.

    Science.gov (United States)

    Loprinzi, Paul D; Schary, David P; Cardinal, Bradley J

    2013-01-01

    The primary purpose of the present study was to examine adherence to current active play and electronic media use guidelines in a sample of US preschool-aged children and to examine whether differences occurred across gender and parental education. 164 parents completed an on-line survey to estimate preschool children's active play and sedentary behaviors. For weekdays, 50% of the sample met the active play guideline with this increasing to 65% during the weekend. With respect to electronic media use, 90% of the sample met guidelines during the week, with the percentage meeting guidelines dropping to 78% during the weekend. A greater percentage of preschool children from high parental education families (83.4 ± 3.3) met electronic media use guidelines on the weekends, compared to preschool children from low parental education families (59.4 ± 8.1) (p = 0.002). Our findings indicate that a substantial portion of preschool children are not meeting active play guidelines and that adherence to active play and electronic media use guidelines may be influenced by parental education.

  12. Charge transfer dynamics from adsorbates to surfaces with single active electron and configuration interaction based approaches

    Energy Technology Data Exchange (ETDEWEB)

    Ramakrishnan, Raghunathan, E-mail: r.ramakrishnan@unibas.ch [Institute of Physical Chemistry, National Center for Computational Design and Discovery of Novel Materials (MARVEL), Department of Chemistry, University of Basel, Klingelbergstrasse 80, CH-4056 Basel (Switzerland); Nest, Mathias [Theoretische Chemie, Technische Universität München, Lichtenbergstr. 4, 85747 Garching (Germany)

    2015-01-13

    Highlights: • We model electron dynamics across cyano alkanethiolates attached to gold cluster. • We present electron transfer time scales from TD-DFT and TD-CI based simulations. • Both DFT and CI methods qualitatively predict the trend in time scales. • TD-CI predicts the experimental relative time scale very accurately. - Abstract: We employ wavepacket simulations based on many-body time-dependent configuration interaction (TD-CI), and single active electron theories, to predict the ultrafast molecule/metal electron transfer time scales, in cyano alkanethiolates bonded to model gold clusters. The initial states represent two excited states where a valence electron is promoted to one of the two virtual π{sup ∗} molecular orbitals localized on the cyanide fragment. The ratio of the two time scales indicate the efficiency of one charge transfer channel over the other. In both our one-and many-electron simulations, this ratio agree qualitatively with each other as well as with the previously reported experimental time scales (Blobner et al., 2012), measured for a macroscopic metal surface. We study the effect of cluster size and the description of electron correlation on the charge transfer process.

  13. Constitutive NADPH-dependent electron transferase activity of the Nox4 dehydrogenase domain.

    Science.gov (United States)

    Nisimoto, Yukio; Jackson, Heather M; Ogawa, Hisamitsu; Kawahara, Tsukasa; Lambeth, J David

    2010-03-23

    NADPH oxidase 4 (Nox4) is constitutively active, while Nox2 requires the cytosolic regulatory subunits p47(phox) and p67(phox) and activated Rac with activation by phorbol 12-myristate 13-acetate (PMA). This study was undertaken to identify the domain on Nox4 that confers constitutive activity. Lysates from Nox4-expressing cells exhibited constitutive NADPH- but not NADH-dependent hydrogen peroxide production with a K(m) for NADPH of 55 +/- 10 microM. The concentration of Nox4 in cell lysates was estimated using Western blotting and allowed calculation of a turnover of approximately 200 mol of H(2)O(2) min(-1) (mol of Nox4)(-1). A chimeric protein (Nox2/4) consisting of the Nox2 transmembrane (TM) domain and the Nox4 dehydrogenase (DH) domain showed H(2)O(2) production in the absence of cytosolic regulatory subunits. In contrast, chimera Nox4/2, consisting of the Nox4 TM and Nox2 DH domains, exhibited PMA-dependent activation that required coexpression of regulatory subunits. Nox DH domains from several Nox isoforms were purified and evaluated for their electron transferase activities. Nox1 DH, Nox2 DH, and Nox5 DH domains exhibited barely detectable activities toward artificial electron acceptors, while the Nox4 DH domain exhibited significant rates of reduction of cytochrome c (160 min(-1), largely superoxide dismutase-independent), ferricyanide (470 min(-1)), and other electron acceptors (artificial dyes and cytochrome b(5)). Rates were similar to those observed for H(2)O(2) production by the Nox4 holoenzyme in cell lysates. The activity required added FAD and was seen with NADPH but not NADH. These results indicate that the Nox4 DH domain exists in an intrinsically activated state and that electron transfer from NADPH to FAD is likely to be rate-limiting in the NADPH-dependent reduction of oxygen by holo-Nox4.

  14. Direct observation of children's preferences and activity levels during interactive and online electronic games.

    Science.gov (United States)

    Sit, Cindy H P; Lam, Jessica W K; McKenzie, Thomas L

    2010-07-01

    Interactive electronic games have recently been popularized and are believed to help promote children's physical activity (PA). The purpose of the study was to examine preferences and PA levels during interactive and online electronic games among overweight and nonoverweight boys and girls. Using a modification of the SOFIT, we systematically observed 70 Hong Kong Chinese children (35 boys, 35 girls; 50 nonoverweight, 20 overweight), age 9 to 12 years, during 2 60-minute recreation sessions and recorded their game mode choices and PA levels. During Session One children could play either an interactive or an online electronic bowling game and during Session Two they could play an interactive or an online electronic running game. Children chose to play the games during 94% of session time and split this time between interactive (52%) and online (48%) versions. They engaged in significantly more moderate-to-vigorous physical activity (MVPA) during interactive games than their online electronic versions (70% vs. 2% of game time). Boys and nonoverweight children expended relatively more energy during the interactive games than girls and overweight children, respectively. New-generation interactive games can facilitate physical activity in children, and given the opportunity children may select them over sedentary versions.

  15. Forces and energetics of intermittent swimming

    Science.gov (United States)

    Floryan, Daniel; Van Buren, Tyler; Smits, Alexander J.

    2017-08-01

    Experiments are reported on intermittent swimming motions. Water tunnel experiments on a nominally two-dimensional pitching foil show that the mean thrust and power scale linearly with the duty cycle, from a value of 0.2 all the way up to continuous motions, indicating that individual bursts of activity in intermittent motions are independent of each other. This conclusion is corroborated by particle image velocimetry (PIV) flow visualizations, which show that the main vortical structures in the wake do not change with duty cycle. The experimental data also demonstrate that intermittent motions are generally energetically advantageous over continuous motions. When metabolic energy losses are taken into account, this conclusion is maintained for metabolic power fractions less than 1.

  16. Energetic Techniques For Planetary Defense

    Science.gov (United States)

    Barbee, B.; Bambacus, M.; Bruck Syal, M.; Greenaugh, K. C.; Leung, R. Y.; Plesko, C. S.

    2017-12-01

    Near-Earth Objects (NEOs) are asteroids and comets whose heliocentric orbits tend to approach or cross Earth's heliocentric orbit. NEOs of various sizes periodically collide with Earth, and efforts are currently underway to discover, track, and characterize NEOs so that those on Earth-impacting trajectories are discovered far enough in advance that we would have opportunities to deflect or destroy them prior to Earth impact, if warranted. We will describe current efforts by the National Aeronautics and Space Administration (NASA) and the National Nuclear Security Administration (NNSA) to assess options for energetic methods of deflecting or destroying hazardous NEOs. These methods include kinetic impactors, which are spacecraft designed to collide with an NEO and thereby alter the NEO's trajectory, and nuclear engineering devices, which are used to rapidly vaporize a layer of NEO surface material. Depending on the amount of energy imparted, this can result in either deflection of the NEO via alteration of its trajectory, or robust disruption of the NEO and dispersal of the remaining fragments. We have studied the efficacies and limitations of these techniques in simulations, and have combined the techniques with corresponding spacecraft designs and mission designs. From those results we have generalized planetary defense mission design strategies and drawn conclusions that are applicable to a range of plausible scenarios. We will present and summarize our research efforts to date, and describe approaches to carrying out planetary defense missions with energetic NEO deflection or disruption techniques.

  17. On energetics of hydrocarbon chemical reactions by ionizing irradiation

    International Nuclear Information System (INIS)

    Zaykin, Yu.A.; Zaykina, R.F.; Mirkin, G.

    2002-01-01

    Complete text of publication follows. The present global energy crisis requires the industry to look for technologies that are more effective and, particularly, less energy consuming. The hydrocarbon processing technology based on the electron radiation-induced thermal chemical conversion has a great potential. Comparing the presently predominant thermocatalytic processing, it is much more energy efficient, because chemical conversions go at a minimal processing temperature and pressure. To compare energy consumption by electron irradiation with thermal and thermocatalytic technologies of hydrocarbon processing one must see major differences between them. While traditional thermocatalytic processes are equilibrium and their energetics can be evaluated based on principles of classic thermodynamics, HEET processing is non-equilibrium and this evaluation approach is not valid for it. However, a theoretical description of radiation-chemical conversion using reaction rate constants determined in thermally equilibrium systems is approximately adequate to radiation processes by substituting equilibrium concentrations of reacting particles as their non-equilibrium concentrations under irradiation. In particular, description of radical reactions initiated by radiation requires substitution of thermally equilibrium radical concentration by much higher concentration defined by the dynamic equilibrium of radical radiation generation and their recombination. The paper presents the comparative analysis of energy consumption in different stages of hydrocarbon processing using classic thermal cracking by heating versus radiation induced cracking. It is shown that in the most energy-consuming stage of processing - the chain reaction initiation necessary for concentration of active radicals, irradiation processing has the great advantage compared to thermal cracking by heating and allows cutting down the total energy consumption by approximately 40%

  18. Site selection of active damper for stabilizing power electronics based power distribution system

    DEFF Research Database (Denmark)

    Yoon, Changwoo; Wang, Xiongfei; Bak, Claus Leth

    2015-01-01

    electronics based power device, which provides an adjustable damping capability to the power system where the voltage harmonic instability is measured. It can stabilize by adjusting the equivalent node impedance with its plug and play feature. This feature gives many degrees of freedom of its installation......Stability in the nowadays distribution power system is endangered by interaction problems that may arise from newly added power-electronics based power devices. Recently, a new concept to deal with this higher frequency instability, the active damper, has been proposed. The active damper is a power...... point when the system has many nodes. Therefore, this paper addresses the proper placement of an active damper in an unstable small-scale power distribution system. A time-domain model of the Cigre benchmark low-vltage network is used as a test field. The result shows the active damper location...

  19. Effect of Electronic Messaging on Physical Activity Participation among Older Adults

    OpenAIRE

    Antoine Parker, Chantrell; Ellis, Rebecca

    2016-01-01

    The purpose of this study was to determine if electronic messaging would increase min of aerobic physical activity (PA) among older adults. Participants were active older adults (n = 28; M age = 60 years, SD = 5.99, and range = 51?74 years). Using an incomplete within-subjects crossover design, participants were randomly assigned to begin the 4-week study receiving the treatment condition (a morning and evening text message) or the control condition (an evening text message). Participants sel...

  20. Electronic Nose Technology to Measure Soil Microbial Activity and Classify Soil Metabolic Status

    OpenAIRE

    Fabrizio De Cesare; Elena Di Mattia; Simone Pantalei; Emiliano Zampetti; Vittorio Vinciguerra; Antonella Macagnano

    2011-01-01

    The electronic nose (E-nose) is a sensing technology that has been widely used to monitor environments in the last decade. In the present study, the capability of an E-nose, in combination with biochemical and microbiological techniques, of both detecting the microbial activity and estimating the metabolic status of soil ecosystems, was tested by measuring on one side respiration, enzyme activities and growth of bacteria in natural but simplified soil ecosystems over 23 days of incubation thr...

  1. Effect of electron beam-irradiation to b-glucan on its immunomodulating and antitumor activity

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Yeon Hwan; Lee, Jung Lim; Yoo, Yung Choon [Konyand Univ., Daejeon (Korea, Republic of); Kim, Jae Hoon; Lee, Ju Woon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2010-07-01

    In this study, in order investigated the effect of electron beam irradiation to b-glucan on its biological activities, we compared immunomodulating and antitumor activity between non-irradiated and electron beam-irradiated b-glucan. EB-glucan was irradiated by electron beam with 10, 30 and 50 kGy. Treatment with EB-glucan resulted in a slight increase of the proliferation of ConA-stimulated splenocytes, and the strongest activity was seen in 50 kGy-treated EB-glucan. EB-glucan teated with 50 kGy also showed increased secretion of cytokines such as IL-2 IFN-{gamma} and IL-6 from ConA-stimulated splenocytes. The activity of EB-glucan to enhance the proliferation of splenocytes and cytokine secretion from ConA-stimulated splenocytes was higher than that of NI-glucan. Furthermore, EB-glucan treated with 50 kGy showed higher activity to activate RAW 264.7 macrophages, comparing with that of NI-glucan. In experiments of antitumor activity, EB-glucan treated with 50 kGy prior to tumor inoculation inhibited an experimental lung metastasis produced by B16-BL6 melanoma cells in mice. But NI-glucan did show no effect. In addition, EB-glucan treated with 50 kGy induced a decrease a decrease of tumor growth in tumor-bearing mice. Collectivelt, these results indicates that electron beam irradiation {beta}-glucan leads its biological functions to enhance immunomodulating and antitumor activity.

  2. Effect of electron beam-irradiation to b-glucan on its immunomodulating and antitumor activity

    International Nuclear Information System (INIS)

    Jung, Yeon Hwan; Lee, Jung Lim; Yoo, Yung Choon; Kim, Jae Hoon; Lee, Ju Woon

    2010-01-01

    In this study, in order investigated the effect of electron beam irradiation to b-glucan on its biological activities, we compared immunomodulating and antitumor activity between non-irradiated and electron beam-irradiated b-glucan. EB-glucan was irradiated by electron beam with 10, 30 and 50 kGy. Treatment with EB-glucan resulted in a slight increase of the proliferation of ConA-stimulated splenocytes, and the strongest activity was seen in 50 kGy-treated EB-glucan. EB-glucan teated with 50 kGy also showed increased secretion of cytokines such as IL-2 IFN-γ and IL-6 from ConA-stimulated splenocytes. The activity of EB-glucan to enhance the proliferation of splenocytes and cytokine secretion from ConA-stimulated splenocytes was higher than that of NI-glucan. Furthermore, EB-glucan treated with 50 kGy showed higher activity to activate RAW 264.7 macrophages, comparing with that of NI-glucan. In experiments of antitumor activity, EB-glucan treated with 50 kGy prior to tumor inoculation inhibited an experimental lung metastasis produced by B16-BL6 melanoma cells in mice. But NI-glucan did show no effect. In addition, EB-glucan treated with 50 kGy induced a decrease a decrease of tumor growth in tumor-bearing mice. Collectivelt, these results indicates that electron beam irradiation β-glucan leads its biological functions to enhance immunomodulating and antitumor activity

  3. 12 CFR 7.5003 - Composite authority to engage in electronic activities.

    Science.gov (United States)

    2010-01-01

    ... 12 Banks and Banking 1 2010-01-01 2010-01-01 false Composite authority to engage in electronic activities. 7.5003 Section 7.5003 Banks and Banking COMPTROLLER OF THE CURRENCY, DEPARTMENT OF THE TREASURY... itself part of or incidental to the business of banking or is otherwise permissible under Federal law. ...

  4. Active Cooling and Thermal Management of a Downhole Tool Electronics Section

    DEFF Research Database (Denmark)

    Soprani, Stefano; Engelbrecht, Kurt; Just Nørgaard, Anders

    2015-01-01

    combines active and passive cooling techniques, aiming at an efficient thermal management, preserving the tool compactness and avoiding the use of moving parts. Thermoelectric coolers were used to transfer the dissipated heat from the temperature-sensitive electronics to the external environment. Thermal...... contact resistances were minimized and thermally insulating foam protected the refrigerated microenvironment from the hot surroundings....

  5. Single-active-electron potentials for molecules in intense laser fields

    DEFF Research Database (Denmark)

    Abu-Samha, Mahmoud; Madsen, Lars Bojer

    2010-01-01

    Single-active-electron potentials are computed for selected molecules, and molecular wave functions with the correct asymptotic behavior are produced. Asymptotic expansion coefficients are extracted from the wave functions and used to compute alignment-dependent ionization yields from molecular...

  6. Observation of energetic particle mode by using microwave reflectometer

    International Nuclear Information System (INIS)

    Tokuzawa, T.; Kawahata, K.; Sakakibara, S.; Toi, K.; Osakabe, M.; Yamamoto, S.

    2006-01-01

    Two heterodyne reflectometer systems are utilized for the fluctuation measurement in the Large Helical Device (LHD). By using the extraordinary polarized wave, we can measure the corresponding value to the combined fluctuation with the electron density and the magnetic field in the plasma core region even if the radial electron density profile is flat. E-band system has three channels of fixed frequencies of 78, 72, 65 GHz. The system is very convenient to observe magnetohydrodynamics (MHD) phenomena such as energetic particle driven Alfven eigenmodes, even if the system works as an interferometer mode. The detailed behaviour of the energetic particle mode is studied when low-n MHD burst is occurred. It seems to be caused that the spatial distribution of high energy particle is changed by such a MHD-burst. Also to know the radial distribution of MHD mode, frequency swept R-band reflectometer is applied for the first time. It seems to be successfully detected the energetic particle mode and toroidal Alfven eigenmode. (author)

  7. THE ENVIRONMENT AND DISTRIBUTION OF EMITTING ELECTRONS AS A FUNCTION OF SOURCE ACTIVITY IN MARKARIAN 421

    International Nuclear Information System (INIS)

    Mankuzhiyil, Nijil; Ansoldi, Stefano; Persic, Massimo; Tavecchio, Fabrizio

    2011-01-01

    For the high-frequency-peaked BL Lac object Mrk 421, we study the variation of the spectral energy distribution (SED) as a function of source activity, from quiescent to active. We use a fully automatized χ 2 -minimization procedure, instead of the 'eyeball' procedure more commonly used in the literature, to model nine SED data sets with a one-zone synchrotron self-Compton (SSC) model and examine how the model parameters vary with source activity. The latter issue can finally be addressed now, because simultaneous broadband SEDs (spanning from optical to very high energy photon) have finally become available. Our results suggest that in Mrk 421 the magnetic field (B) decreases with source activity, whereas the electron spectrum's break energy (γ br ) and the Doppler factor (δ) increase-the other SSC parameters turn out to be uncorrelated with source activity. In the SSC framework, these results are interpreted in a picture where the synchrotron power and peak frequency remain constant with varying source activity, through a combination of decreasing magnetic field and increasing number density of γ ≤ γ br electrons: since this leads to an increased electron-photon scattering efficiency, the resulting Compton power increases, and so does the total (= synchrotron plus Compton) emission.

  8. Abundances, Ionization States, Temperatures, and FIP in Solar Energetic Particles

    Science.gov (United States)

    Reames, Donald V.

    2018-04-01

    The relative abundances of chemical elements and isotopes have been our most effective tool in identifying and understanding the physical processes that control populations of energetic particles. The early surprise in solar energetic particles (SEPs) was 1000-fold enhancements in {}3He/{}4He from resonant wave-particle interactions in the small "impulsive" SEP events that emit electron beams that produce type III radio bursts. Further studies found enhancements in Fe/O, then extreme enhancements in element abundances that increase with mass-to-charge ratio A/Q, rising by a factor of 1000 from He to Au or Pb arising in magnetic reconnection regions on open field lines in solar jets. In contrast, in the largest SEP events, the "gradual" events, acceleration occurs at shock waves driven out from the Sun by fast, wide coronal mass ejections (CMEs). Averaging many events provides a measure of solar coronal abundances, but A/Q-dependent scattering during transport causes variations with time; thus if Fe scatters less than O, Fe/O is enhanced early and depleted later. To complicate matters, shock waves often reaccelerate impulsive suprathermal ions left over or trapped above active regions that have spawned many impulsive events. Direct measurements of ionization states Q show coronal temperatures of 1-2 MK for most gradual events, but impulsive events often show stripping by matter traversal after acceleration. Direct measurements of Q are difficult and often unavailable. Since both impulsive and gradual SEP events have abundance enhancements that vary as powers of A/Q, we can use abundances to deduce the probable Q-values and the source plasma temperatures during acceleration, ≈3 MK for impulsive SEPs. This new technique also allows multiple spacecraft to measure temperature variations across the face of a shock wave, measurements otherwise unavailable and provides a new understanding of abundance variations in the element He. Comparing coronal abundances from SEPs

  9. Energetic materials and methods of tailoring electrostatic discharge sensitivity of energetic materials

    Energy Technology Data Exchange (ETDEWEB)

    Daniels, Michael A.; Heaps, Ronald J.; Wallace, Ronald S.; Pantoya, Michelle L.; Collins, Eric S.

    2016-11-01

    An energetic material comprising an elemental fuel, an oxidizer or other element, and a carbon nanofiller or carbon fiber rods, where the carbon nanofiller or carbon fiber rods are substantially homogeneously dispersed in the energetic material. Methods of tailoring the electrostatic discharge sensitivity of an energetic material are also disclosed.

  10. Exploring the Role of Persulfate in the Activation Process: Radical Precursor Versus Electron Acceptor.

    Science.gov (United States)

    Yun, Eun-Tae; Yoo, Ha-Young; Bae, Hyokwan; Kim, Hyoung-Il; Lee, Jaesang

    2017-09-05

    This study elucidates the mechanism behind persulfate activation by exploring the role of various oxyanions (e.g., peroxymonosulfate, periodate, and peracetate) in two activation systems utilizing iron nanoparticle (nFe 0 ) as the reducing agent and single-wall carbon nanotubes (CNTs) as electron transfer mediators. Since the tested oxyanions serve as both electron acceptors and radical precursors in most cases, oxidative degradation of organics was achievable through one-electron reduction of oxyanions on nFe 0 (leading to radical-induced oxidation) and electron transfer mediation from organics to oxyanions on CNTs (leading to oxidative decomposition involving no radical formation). A distinction between degradative reaction mechanisms of the nFe 0 /oxyanion and CNT/oxyanion systems was made in terms of the oxyanion consumption efficacy, radical scavenging effect, and EPR spectral analysis. Statistical study of substrate-specificity and product distribution implied that the reaction route induced on nFe 0 varies depending on the oxyanion (i.e., oxyanion-derived radical), whereas the similar reaction pathway initiates organic oxidation in the CNT/oxyanion system irrespective of the oxyanion type. Chronoamperometric measurements further confirmed electron transfer from organics to oxyanions in the presence of CNTs, which was not observed when applying nFe 0 instead.

  11. Acceleration and propagation of energetic particles in the solar corona: from RHESSI data analysing to the preparation of the STIX tool operations on Solar Orbiter

    International Nuclear Information System (INIS)

    Musset, S.

    2016-01-01

    The Sun is an active star and one manifestation of its activity is the production of solar flares. It is currently admitted that solar flares are caused by the release of magnetic energy during the process of magnetic reconnection in the solar upper atmosphere, the solar corona. During these flares, a large fraction of the magnetic energy is transferred to the acceleration of particles (electrons and ions). However, the details of particle acceleration during flares are still not completely understood. Several scenarios and models have been developed to explain particle acceleration. In some of them, electric fields, produced at the location of current sheets, which can be fragmented or collapsing, and which are preferentially located on quasi-separatrix layers (QSLs), are accelerating particles. To investigate a possible link between energetic particles and direct electric fields produced at current sheet locations, we looked for a correlation between X-ray emission from energetic electrons and electric currents which can be measured at the photospheric level. We used the Reuven Ramaty High Energy Solar Spectrometric Imager (RHESSI) data to produce spectra and images of the X-ray emissions during GOES X-class flares, and spectro polarimetric data from the Helio seismic and Magnetic Imager (HMI) onboard the Solar Dynamics Observatory (SDO) to calculate the vertical current densities from the reconstructed 3D vector magnetic field. A correlation between the coronal X-ray emissions (tracing the energetic electrons near the acceleration site) and the strong current ribbons at the photospheric level (tracing the coronal current sheet) was found in the five studied X-class flares. Moreover, thanks to the 12-minute time cadence of SDO/HMI, we could study for the first time the time evolution of electric currents : in several flares, a change in the current intensity, occurring during the flare peak, was found to be spatially correlated with X-ray emission sites. These

  12. Prescribing of Electronic Activity Monitors in Cardiometabolic Diseases: Qualitative Interview-Based Study.

    Science.gov (United States)

    Bellicha, Alice; Macé, Sandrine; Oppert, Jean-Michel

    2017-09-23

    The prevalence of noncommunicable diseases, including those such as type 2 diabetes, obesity, dyslipidemia, and hypertension, so-called cardiometabolic diseases, is high and is increasing worldwide. Strong evidence supports the role of physical activity in management of these diseases. There is general consensus that mHealth technology, including electronic activity monitors, can potentially increase physical activity in patients, but their use in clinical settings remains limited. Practitioners' requirements when prescribing electronic activity monitors have been poorly described. The aims of this qualitative study were (1) to explore how specialist physicians prescribe electronic activity monitors to patients presenting with cardiometabolic conditions, and (2) to better understand their motivation for and barriers to prescribing such monitors. We conducted qualitative semistructured interviews in March to May 2016 with 11 senior physicians from a public university hospital in France with expertise in management of cardiometabolic diseases (type 1 and type 2 diabetes, obesity, hypertension, and dyslipidemia). Interviews lasted 45 to 60 minutes and were audiotaped, transcribed verbatim, and analyzed using directed content analysis. We report our findings following the Consolidated Criteria for Reporting Qualitative Research (COREQ) checklist. Most physicians we interviewed had never prescribed electronic activity monitors, whereas they frequently prescribed blood glucose or blood pressure self-monitoring devices. Reasons for nonprescription included lack of interest in the data collected, lack of evidence for data accuracy, concern about work overload possibly resulting from automatic data transfer, and risk of patients becoming addicted to data. Physicians expected future marketing of easy-to-use monitors that will accurately measure physical activity duration and intensity and provide understandable motivating feedback. Features of electronic activity monitors

  13. Quasi-Linear Evolution of Trapped Electron Fluxes Under the Influence of Realistic Whistler-Mode Waves

    Science.gov (United States)

    Agapitov, O. V.; Mourenas, D.; Artemyev, A.; Krasnoselskikh, V.

    2014-12-01

    The evolution of fluxes of energetic trapped electrons as a function of geomagnetic activity is investigated using brand new statistical models of chorus waves derived from Cluster observations in the radiation belts. The new wave models provide the distributions of wave power and wave-normal angle with latitude as a function of either Dst or Kp indices. Lifetimes and energization of energetic electrons are examined, as well as the relevant uncertainties related to some of the wave models implicit assumptions.From the presented results, different implications concerning the characterization of relativistic flux enhancements and losses are provided.

  14. Energetic evolution of cellular Transportomes

    DEFF Research Database (Denmark)

    Darbani, Behrooz; Kell, Douglas B.; Borodina, Irina

    2018-01-01

    of the transition from prokaryotes to eukaryotes. The transportome analysis also indicated seven bacterial species, including Neorickettsia risticii and Neorickettsia sennetsu, as likely origins of the mitochondrion in eukaryotes, based on the phylogenetically restricted presence therein of clear homologues......) than in primitive eukaryotes (13%), algae and plants (10%) and in fungi and animals (5–6%). This decrease is compensated by an increased occurrence of secondary transporters and ion channels. The share of ion channels is particularly high in animals (ca. 30% of the transportome) and algae and plants...... of modern mitochondrial solute carriers. Conclusions: The results indicate that the transportomes of eukaryotes evolved strongly towards a higher energetic efficiency, as ATP-dependent transporters diminished and secondary transporters and ion channels proliferated. These changes have likely been important...

  15. Cosmic Ray Energetics and Mass

    CERN Multimedia

    Baylon cardiel, J L; Wallace, K C; Anderson, T B; Copley, M

    The cosmic-ray energetics and mass (CREAM) investigation is designed to measure cosmic-ray composition to the supernova energy scale of 10$^{15}$ eV in a series of ultra long duration balloon (ULDB) flights. The first flight is planned to be launched from Antarctica in December 2004. The goal is to observe cosmic-ray spectral features and/or abundance changes that might signify a limit to supernova acceleration. The particle ($\\{Z}$) measurements will be made with a timing-based charge detector and a pixelated silicon charge detector to minimize the effect of backscatter from the calorimeter. The particle energy measurements will be made with a transition radiation detector (TRD) for $\\{Z}$ > 3 and a sampling tungsten/scintillator calorimeter for $\\{Z}$ $\\geq$1 particles, allowing inflight cross calibration of the two detectors. The status of the payload construction and flight preparation are reported in this paper.

  16. Energetic model of metal hardening

    Directory of Open Access Journals (Sweden)

    Ignatova O.N.

    2011-01-01

    Full Text Available Based on Bailey hypothesis on the link between strain hardening and elastic lattice defect energy this paper suggests a shear strength energetic model that takes into consideration plastic strain intensity and rate as well as softening related to temperature annealing and dislocation annihilation. Metal strain hardening was demonstrated to be determined only by elastic strain energy related to the energy of accumulated defects. It is anticipated that accumulation of the elastic energy of defects is governed by plastic work. The suggested model has a reasonable agreement with the available experimental data for copper up to P = 70 GPa , for aluminum up to P = 10 GPa and for tantalum up to P = 20 GPa.

  17. Comparative effects of exposure to high-energy electrons and gamma radiation on active avoidance behaviour

    International Nuclear Information System (INIS)

    Hunt, W.A.

    1983-01-01

    The effect of two types of ionizing radiation was examined on active avoidance behaviour. Male Sprague-Dawley rats were trained to avoid footshock by jumping onto a retractable ledge. When irradiated with high-energy electrons or gamma photons, their performance was degraded in a dose-dependent manner. However, electrons were 1.6 times as effective as gamma photons with ED50s of 62 and 102 Gy, respectively. All animals recovered within 24 min for all doses used. The data suggest that different types of ionizing radiation may not be equivalent when assessing their effect on behaviour. (author)

  18. Electron transport in solid targets and in the active mixture of a CO2 laser amplifier

    Science.gov (United States)

    Galkowski, A.

    The paper examines the use of the NIKE code for the Monte Carlo computation of the deposited energy profile and other characteristics of the absorption process of an electron beam in a solid target and the spatial distribution of primary ionization in the active mixture of a CO2 laser amplifier. The problem is considered in connection with the generation of intense electron beams and the acceleration of thin metal foils, as well as in connection with the electric discharge pumping of a CO2 laser amplifier.

  19. Continuous engineering of nano-cocrystals for medical and energetic applications

    Science.gov (United States)

    Spitzer, D.; Risse, B.; Schnell, F.; Pichot, V.; Klaumünzer, M.; Schaefer, M. R.

    2014-10-01

    Cocrystals, solid mixtures of different molecules on molecular scale, are supposed to be tailor made materials with improved employability compared to their pristine individual components in domains such as medicine and explosives. In medicine, cocrystals are obtained by crystallization of active pharmaceutical ingredients with precisely chosen coformers to design medicaments that demonstrate enhanced stability, high solubility, and therefore high bioavailability and optimized drug up-take. Nanoscaling may further advance these characteristica compared to their micronsized counterparts - because of a larger surface to volume ratio of nanoparticles. In the field of energetic materials, cocrystals offer the opportunity to design smart explosives, combining high reactivity with significantly reduced sensitivity, nowadays essential for a safe manipulation and handling. Furthermore, cocrystals are used in ferroelectrics, non-linear material response and electronic organics. However, state of the art batch processes produce low volume of cocrystals of variable quality and only have produced micronsized cocrystals so far, no nano-cocrystals. Here we demonstrate the continuous preparation of pharmaceutical and energetic micro- and nano-cocrystals using the Spray Flash Evaporation process. Our laboratory scale pilot plant continuously prepared up to 8 grams per hour of Caffeine/Oxalic acid 2:1, Caffeine/Glutaric acid 1:1, TNT/CL-20 1:1 and HMX/Cl-20 1:2 nano- and submicronsized cocrystals.

  20. Surface characterization of activated chalcopyrite particles via the FLSmidth ROL process. Part 1: Electron microscope investigations

    DEFF Research Database (Denmark)

    Karcz, Adam Paul; Damø, Anne Juul; Illerup, Jytte Boll

    Because of its unique semiconductor properties, the world’s most abundant copper mineral (chalcopyrite) is refractory with respect to atmospheric leaching using traditional ferric sulfate lixiviants. A novel approach to address this issue – conducted at FLSmidth – utilizes a mechanochemical Rapid...... of copper(II) to dope the semiconductor lattice and thereby "activate" the chalcopyrite, thereby reducing leach times below 2 hours (>98% recovery). Because the activation plays a major role in accelerating the leaching step, it is critical to understand the nature of this intermediate and its part...... in the ROL process. The current work presents results from electron microscope investigations of surface-activated particles....

  1. Ecological problems of thermonuclear energetics. Review

    Energy Technology Data Exchange (ETDEWEB)

    Sivintsev, Yu V

    1980-01-01

    A review of preliminary quantitative estimates of radiation hazard of thermonuclear reactors is presented. Main attention is given to three aspects: nonradiation effect on environment, radionuclide blow-ups at normal operation and emergency situations with their consequences. The given data testify to great radiological advantages of thermonuclear energetics as compared with the modern nuclear energetics with thermal and prospective fast reactors.

  2. Energetic proton generation in ultra-intense laser-solid interactions

    International Nuclear Information System (INIS)

    Wilks, S.C.; Langdon, A.B.; Cowan, T.E.; Roth, M.; Singh, M.; Hatchett, S.; Key, M. H.; Pennington, D.; MacKinnon, A.; Snavely, R.A.

    2001-01-01

    An explanation for the energetic ions observed in the PetaWatt experiments is presented. In solid target experiments with focused intensities exceeding 10 20 W/cm 2 , high-energy electron generation, hard bremsstrahlung, and energetic protons have been observed on the backside of the target. In this report, an attempt is made to explain the physical process present that will explain the presence of these energetic protons, as well as explain the number, energy, and angular spread of the protons observed in experiment. In particular, we hypothesize that hot electrons produced on the front of the target are sent through to the back off the target, where they ionize the hydrogen layer there. These ions are then accelerated by the hot electron cloud, to tens of MeV energies in distances of order tens of μm, whereupon they end up being detected in the radiographic and spectrographic detectors

  3. Energetic prediction on the stability of A2Mg12Si7, A2Mg4Si3, and AMgSi in the A2Si–Mg2Si system (A = Ca, Sr and Ba) and their calculated electronic structures

    International Nuclear Information System (INIS)

    Imai, Yoji; Mori, Yoshihisa; Nakamura, Shigeyuki; Takarabe, Ken-ichi

    2014-01-01

    Highlights: • Formation energies of A 2 Mg 4 Si 3 , A 2 Mg 12 Si 7 , and AMgSi (A = Ca,Sr,Ba) were calculated. • All AMgSi are quite stable compared to mixture of A 2 Si and Mg 2 Si. • Ba 2 Mg 4 Si 3 and Sr 2 Mg 4 Si 3 are predicted to be stable, but Ca 2 Mg 4 Si 3 is not. • Ca 2 Mg 12 Si 7 and Sr 2 Mg 12 Si 7 are energetically unstable. • Stability of Ba 2 Mg 12 Si 7 is a tender subject. -- Abstract: In order to evaluate the relative stability of A 2 Mg 4 Si 3 , A 2 Mg 12 Si 7 , and AMgSi (A = Ca, Sr, and Ba) in the A 2 Si–Mg 2 Si system, electronic energy changes in the formation of these compounds were calculated using a density-functional theory with the Perdew–Wang generalized gradient approximations. It was found that (1) AMgSi’s are quite stable compared to equi-molar mixture of A 2 Si and Mg 2 Si, (2) Ba 2 Mg 4 Si 3 and Sr 2 Mg 4 Si 3 are also stable, (3) Ca 2 Mg 4 Si 3 and Ca 2 Mg 12 Si 7 are less stable than the mixture of CaMgSi and Mg 2 Si, and (4) Stability of Ba 2 Mg 12 Si 7 is a tender subject and Sr 2 Mg 12 Si 7 is energetically unstable compared to the mixture of Sr 2 Mg 4 Si 3 (or, SrMgSi) and Mg 2 Si. The presence of Sr 2 Mg 12 Si 7 may be due to the vibrational and/or configurational entropy, which are not treated in the present study. From the calculated electronic densities of state, complex compounds of SrMgSi and Mg 2 Si have both p-type and n-type character, depending on the ratio of SrMgSi and Mg 2 Si in that compound

  4. Comparison of experimental slant electron content and IRI model for moderate solar activity conditions

    International Nuclear Information System (INIS)

    Cabrera, M.A.; Ezquer, R.G.; Mosert, M.; Jadur, C.A.

    2002-01-01

    The International Reference Ionosphere model only gives the vertical electron content (VTEC). In this paper the slant electron content (SEC) for the ATS 6 satellite - Palehua (21.4 deg. N, 201.9 deg. E) radio signal path for a middle solar activity year is calculated. To this end, IRI model is used to obtain the electron density at different points of the signal path. Equinoxes and solstices are considered. Measurements obtained with Faraday rotation technique at Palehua are compared with the modelled values. Although overestimation was observed for night hours, the results show good SEC predictions for several hours at period of maximum ionisation, suggesting that would be possible to model the STEC using IRI. (author)

  5. Sawtooth activity of the ion cloud in an electron-beam ion trap

    International Nuclear Information System (INIS)

    Radtke, R.; Biedermann, C.

    2003-01-01

    The dynamics of an ensemble of highly charged Ar and Ba ions in an electron-beam ion trap (EBIT) was studied by recording time-resolved x-ray spectra emitted from trapped ions. Sawtoothlike signatures manifest in the spectra for a variety of EBIT operating conditions indicating a sudden collapse of the ion inventory in the trap. The collapse occurs on a time scale of approximately 100 ms and the evolution of the sawteeth is very sensitive to parameters such as electron-beam current and axial trap depth. Analysis of the measurements is based on a time-dependent calculation of the trapping process showing that sawtooth activity is caused by the feedback between the low-Z argon and high-Z barium ions. This unexpected behavior demonstrates the importance of nonlinear effects in electron-beam traps containing more than a single ion species

  6. Apparatus and method for extracting power from energetic ions produced in nuclear fusion

    Science.gov (United States)

    Fisch, Nathaniel J.; Rax, Jean M.

    1994-01-01

    An apparatus and method of extracting power from energetic ions produced by nuclear fusion in a toroidal plasma to enhance respectively the toroidal plasma current and fusion reactivity. By injecting waves of predetermined frequency and phase traveling substantially in a selected poloidal direction within the plasma, the energetic ions become diffused in energy and space such that the energetic ions lose energy and amplify the waves. The amplified waves are further adapted to travel substantially in a selected toroidal direction to increase preferentially the energy of electrons traveling in one toroidal direction which, in turn, enhances or generates a toroidal plasma current. In an further adaptation, the amplified waves can be made to preferentially increase the energy of fuel ions within the plasma to enhance the fusion reactivity of the fuel ions. The described direct, or in situ, conversion of the energetic ion energy provides an efficient and economical means of delivering power to a fusion reactor.

  7. Surface-Plasmon-Driven Hot Electron Photochemistry.

    Science.gov (United States)

    Zhang, Yuchao; He, Shuai; Guo, Wenxiao; Hu, Yue; Huang, Jiawei; Mulcahy, Justin R; Wei, Wei David

    2017-11-30

    Visible-light-driven photochemistry has continued to attract heightened interest due to its capacity to efficiently harvest solar energy and its potential to solve the global energy crisis. Plasmonic nanostructures boast broadly tunable optical properties coupled with catalytically active surfaces that offer a unique opportunity for solar photochemistry. Resonant optical excitation of surface plasmons produces energetic hot electrons that can be collected to facilitate chemical reactions. This review sums up recent theoretical and experimental approaches for understanding the underlying photophysical processes in hot electron generation and discusses various electron-transfer models on both plasmonic metal nanostructures and plasmonic metal/semiconductor heterostructures. Following that are highlights of recent examples of plasmon-driven hot electron photochemical reactions within the context of both cases. The review concludes with a discussion about the remaining challenges in the field and future opportunities for addressing the low reaction efficiencies in hot-electron-induced photochemistry.

  8. Behavior change techniques implemented in electronic lifestyle activity monitors: a systematic content analysis.

    Science.gov (United States)

    Lyons, Elizabeth J; Lewis, Zakkoyya H; Mayrsohn, Brian G; Rowland, Jennifer L

    2014-08-15

    Electronic activity monitors (such as those manufactured by Fitbit, Jawbone, and Nike) improve on standard pedometers by providing automated feedback and interactive behavior change tools via mobile device or personal computer. These monitors are commercially popular and show promise for use in public health interventions. However, little is known about the content of their feedback applications and how individual monitors may differ from one another. The purpose of this study was to describe the behavior change techniques implemented in commercially available electronic activity monitors. Electronic activity monitors (N=13) were systematically identified and tested by 3 trained coders for at least 1 week each. All monitors measured lifestyle physical activity and provided feedback via an app (computer or mobile). Coding was based on a hierarchical list of 93 behavior change techniques. Further coding of potentially effective techniques and adherence to theory-based recommendations were based on findings from meta-analyses and meta-regressions in the research literature. All monitors provided tools for self-monitoring, feedback, and environmental change by definition. The next most prevalent techniques (13 out of 13 monitors) were goal-setting and emphasizing discrepancy between current and goal behavior. Review of behavioral goals, social support, social comparison, prompts/cues, rewards, and a focus on past success were found in more than half of the systems. The monitors included a range of 5-10 of 14 total techniques identified from the research literature as potentially effective. Most of the monitors included goal-setting, self-monitoring, and feedback content that closely matched recommendations from social cognitive theory. Electronic activity monitors contain a wide range of behavior change techniques typically used in clinical behavioral interventions. Thus, the monitors may represent a medium by which these interventions could be translated for

  9. Are associations between electronic media use and BMI different across levels of physical activity?

    DEFF Research Database (Denmark)

    Melkevik, Ole; Haug, Ellen; Rasmussen, Mette

    2015-01-01

    and girls who did not comply with physical activity guidelines. Among physically active adolescents, EM was found to be significantly associated with BMI or odds for overweight among girls, but not among boys. CONCLUSION: While the usage of EM appear to be inconsequential for BMI and the risk of overweight...... among physically active boys, we find evidence indicating that EM use is associated with BMI and risk for overweight among girls, including those who report complying with MVPA guidelines.......BACKGROUND: The use of electronic media has been found to be a risk factor for higher BMI and for being overweight. Physical activity has been found to be associated with lower BMI and lower risk for being overweight. Little is known about whether the associations between physical activity...

  10. Electronic screens in children's bedrooms and adiposity, physical activity and sleep: do the number and type of electronic devices matter?

    Science.gov (United States)

    Chaput, Jean-Philippe; Leduc, Geneviève; Boyer, Charles; Bélanger, Priscilla; LeBlanc, Allana G; Borghese, Michael M; Tremblay, Mark S

    2014-07-11

    To examine whether the number and type of electronic screens available in children's bedrooms matter in their relationship to adiposity, physical activity and sleep. A cross-sectional study was conducted involving 502 children aged 9-11 years from Ottawa, Ontario. The presence (yes/no) of a television (TV), computer or video game system in the child's bedroom was reported by the parents. Percentage body fat was measured using bioelectrical impedance. An accelerometer was worn over seven days to assess moderate-to-vigorous physical activity (MVPA), total sedentary time, sleep duration and sleep efficiency. Screen time was self-reported by the child. After adjustment for age, sex, ethnicity, annual household income and highest level of parental education, children with 2-3 screens in their bedroom had a significantly higher percentage of body fat than children with no screen in their bedroom. However, while children with 2-3 screens in their bedroom engaged in more screen time overall than those with no screen, total sedentary time and MVPA were not significantly different. Sleep duration was not related to the number of screens in the bedroom, but sleep efficiency was significantly lower in children with at least 2 screens in the bedroom. Finally, children having only a TV in their bedroom had significantly higher adiposity than those having no screen at all. In contrast, the presence of a computer in children's bedrooms was not associated with higher adiposity than that of children with no screen. A higher number of screens in a child's bedroom was associated with higher adiposity, more total screen time and lower sleep efficiency. Having a TV in the bedroom appears to be the type of screen presence associated with higher levels of adiposity. Given the popularity of screens among children, these findings are increasingly relevant to health promotion strategies.

  11. Top-down Fabrication and Enhanced Active Area Electronic Characteristics of Amorphous Oxide Nanoribbons for Flexible Electronics.

    Science.gov (United States)

    Jang, Hyun-June; Joong Lee, Ki; Jo, Kwang-Won; Katz, Howard E; Cho, Won-Ju; Shin, Yong-Beom

    2017-07-18

    Inorganic amorphous oxide semiconductor (AOS) materials such as amorphous InGaZnO (a-IGZO) possess mechanical flexibility and outstanding electrical properties, and have generated great interest for use in flexible and transparent electronic devices. In the past, however, AOS devices required higher activation energies, and hence higher processing temperatures, than organic ones to neutralize defects. It is well known that one-dimensional nanowires tend to have better carrier mobility and mechanical strength along with fewer defects than the corresponding two-dimensional films, but until now it has been difficult, costly, and impractical to fabricate such nanowires in proper alignments by either "bottom-up" growth techniques or by "top-down" e-beam lithography. Here we show a top-down, cost-effective, and scalable approach for the fabrication of parallel, laterally oriented AOS nanoribbons based on lift-off and nano-imprinting. High mobility (132 cm 2 /Vs), electrical stability, and transparency are obtained in a-IGZO nanoribbons, compared to the planar films of the same a-IGZO semiconductor.

  12. ENERGETIC FERMI/LAT GRB 100414A: ENERGETIC AND CORRELATIONS

    International Nuclear Information System (INIS)

    Urata, Yuji; Tsai, Patrick P.; Huang, Kuiyun; Yamaoka, Kazutaka; Tashiro, Makoto S.

    2012-01-01

    This study presents multi-wavelength observational results for energetic GRB 100414A with GeV photons. The prompt spectral fitting using Suzaku/WAM data yielded spectral peak energies of E src peak of 1458.7 +132.6 –106.6 keV and E iso of 34.5 +2.0 –1.8 × 10 52 erg with z = 1.368. The optical afterglow light curves between 3 and 7 days were effectively fitted according to a simple power law with a temporal index of α = –2.6 ± 0.1. The joint light curve with earlier Swift/UVOT observations yields a temporal break at 2.3 ± 0.2 days. This was the first Fermi/LAT detected event that demonstrated the clear temporal break in the optical afterglow. The jet opening angle derived from this temporal break was 5. 0 8, consistent with those of other well-observed long gamma-ray bursts (GRBs). The multi-wavelength analyses in this study showed that GRB 100414A follows E src peak -E iso and E src peak -E γ correlations. The late afterglow revealed a flatter evolution with significant excesses at 27.2 days. The most straightforward explanation for the excess is that GRB 100414A was accompanied by a contemporaneous supernova. The model light curve based on other GRB-SN events is marginally consistent with that of the observed light curve.

  13. University of Rochester, Laboratory for Laser Energetics

    Science.gov (United States)

    1987-01-01

    In FY86 the Laboratory has produced a list of accomplishments in which it takes pride. LLE has met every laser-fusion program milestone to date in a program of research for direct-drive ultraviolet laser fusion originally formulated in 1981. LLE scientists authored or co-authored 135 scientific papers during 1985 to 1986. The collaborative experiments with NRL, LANL, and LLNL have led to a number of important ICF results. The cryogenic target system developed by KMS Fusion for LLE will be used in future high-density experiments on OMEGA to demonstrate the compression of thermonuclear fuel to 100 to 200 times that of solid (20 to 40 g/cm) in a test of the direct-drive concept, as noted in the National Academy of Sciences' report. The excellence of the advanced technology efforts at LLE is illustrated by the establishment of the Ultrafast Science Center by the Department of Defense through the Air Force Office of Scientific Research. Research in the Center will concentrate on bridging the gap between high-speed electronics and ultrafast optics by providing education, research, and development in areas critical to future communications and high-speed computer systems. The Laboratory for Laser Energetics continues its pioneering work on the interaction of intense radiation with matter. This includes inertial-fusion and advanced optical and optical electronics research; training people in the technology and applications of high-power, short-pulse lasers; and interacting with the scientific community, business, industry, and government to promote the growth of laser technology.

  14. Electronic interactions decreasing the activation barrier for the hydrogen electro-oxidation reaction

    International Nuclear Information System (INIS)

    Santos, Elizabeth; Schmickler, Wolfgang

    2008-01-01

    A unified model for electrochemical electron transfer reactions which explicitly accounts for the electronic structure of the electrode recently proposed by us is applied to the hydrogen oxidation reaction at different metal electrocatalysts. We focus on the changes produced in the transition state (saddle point) as a consequence of the interactions with d-bands. We discuss different empirical correlations between properties of the metal and catalytic activity proposed in the past. We show which role is played by the band structure of the different metals and its interaction with the molecule for decreasing the activation barrier. Finally, we demonstrate why some metals are better electrocatalysts for the hydrogen electro-oxidation reaction than others

  15. Fast wave current drive on ITER in the presence of energetic alphas

    International Nuclear Information System (INIS)

    Mau, T.K.

    1989-01-01

    The impact of energetic alpha particle wave absorption on the range of frequencies for efficient fast wave current drive in an ITER-like fusion reactor core is investigated. The energetic alpha damping decrement is calculated, using an exact slowing down distribution function, and compared to electron and fuel ion damping over a wide range of frequencies. A combination of strong alpha damping and edge electron absorption in the higher ion harmonic regime limits efficient core fast wave current drive to the lower harmonics (1=2.3). However, high frequency fast waves may be employed to generate current in the outer plasma region. 11 refs., 7 figs

  16. Latitudinal variation of the topside electron temperature at different levels of solar activity

    Czech Academy of Sciences Publication Activity Database

    Truhlík, Vladimír; Bilitza, D.; Třísková, Ludmila

    2009-01-01

    Roč. 44, č. 6 (2009), s. 693-700 ISSN 0273-1177 R&D Projects: GA AV ČR IAA300420603 Grant - others: NASA (US) NNH06CD17C Institutional research plan: CEZ:AV0Z30420517 Keywords : Electron temperature * Solar activity variation * Latitudinal dependence Subject RIV: DG - Athmosphere Sciences, Meteorology Impact factor: 1.079, year: 2009

  17. Effect of electron-ion treatment on fermentative activity of food yeasts

    International Nuclear Information System (INIS)

    Sergeev, I.N.; Ostapenkov, A.M.

    1988-01-01

    Investigation into effect of electron-ion treatment (EIT) on fermentative activity (FA) of Sacch cerevisial type yeasts of 12 breed was conducted. It is shown that even within the limits of one and the same type different treatment regimes are meded. This is obviously connected with physiologic peculiarities of different yeast breeds. Therefore an individual optimal treatment regime should be determined in each particular case during EIT of different breeds

  18. An electronic implementation for Liao's chaotic delayed neuron model with non-monotonous activation function

    International Nuclear Information System (INIS)

    Duan Shukai; Liao Xiaofeng

    2007-01-01

    A new chaotic delayed neuron model with non-monotonously increasing transfer function, called as chaotic Liao's delayed neuron model, was recently reported and analyzed. An electronic implementation of this model is described in detail. At the same time, some methods in circuit design, especially for circuit with time delayed unit and non-monotonously increasing activation unit, are also considered carefully. We find that the dynamical behaviors of the designed circuits are closely similar to the results predicted by numerical experiments

  19. Electronic states of carbon alloy catalysts and nitrogen substituent effects on catalytic activity

    Science.gov (United States)

    Hata, Tomoyuki; Ushiyama, Hiroshi; Yamashita, Koichi

    2013-03-01

    In recent years, Carbon Alloy Catalysts (CACs) are attracting attention as a candidate for non-platinum-based cathode catalysts in fuel cells. Oxygen reduction reactions at the cathode are divided into two elementary processes, electron transfer and oxygen adsorption. The electron transfer reaction is the rate-determining, and by comparison of energy levels, catalytic activity can be evaluated quantitatively. On the other hand, to begin with, adsorption mechanism is obscure. The purpose of this study is to understand the effect of nitrogen substitution and oxygen adsorption mechanism, by first-principle electronic structure calculations for nitrogen substituted models. To reproduce the elementary processes of oxygen adsorption, we assumed that the initial structures are formed based on the Pauling model, a CACs model and nitrogen substituted CACs models in which various points are replaced with nitrogen. When we try to focus only on the DOS peaks of oxygen, in some substituted model that has high adsorption activity, a characteristic partial occupancy state was found. We conclude that this state will affect the adsorption activity, and discuss on why partially occupied states appear with simplification by using an orbital correlation diagram.

  20. SU-F-T-656: Monte Carlo Study On Air Activation Around a Medical Electron Linac

    International Nuclear Information System (INIS)

    Horst, F; Fehrenbacher, G; Zink, K

    2016-01-01

    Purpose: In high energy photon therapy, several radiation protection issues result from photonuclear reactions. The activation of air - directly by photonuclear reactions as well as indirectly by capture of photoneutrons generated inside the linac head - is a major point of concern for the medical staff. The purpose of this study was to estimate the annual effective dose to medical workers due to activated air around a medical high energy electron linac by means of Monte Carlo simulations. Methods: The treatment head of a Varian Clinac in 18 MV-X mode as well as the surrounding concrete bunker were modeled and the radiation transport was simulated using the Monte Carlo code FLUKA, starting from the primary electron striking the bremsstrahlung target. The activation yields in air from photo-disintegration of O-16 and N-14 nuclei as well as from neutron capture on Ar-40 nuclei were obtained from the simulations. The activation build-up, radioactive decay and air ventilation were studied using a mathematical model. The annual effective dose to workers was estimated by using published isotope specific conversion factors. Results: The oxygen and nitrogen activation yields were in contrast to the argon activation yield found to be field size dependent. The impact of the treatment room ventilation on the different air activation products was investigated and quantified. An estimate with very conservative assumptions gave an annual effective dose to workers of < 1 mSv/a. Conclusion: From the results of this study it can be concluded that the contribution of air activation to the radiation exposure to medical workers should be negligible in modern photon therapy, especially when it is compared to the dose due to prompt neutrons and the activation of heavy solid materials such as the jaws and the collimators inside the linac head.

  1. SU-F-T-656: Monte Carlo Study On Air Activation Around a Medical Electron Linac

    Energy Technology Data Exchange (ETDEWEB)

    Horst, F [Institute of Medical Physics and Radiation Protection, University of Applied Sciences, Giessen (Germany); GSI Helmholtz Centre for Heavy Ion Research, Darmstadt (Germany); Fehrenbacher, G [GSI Helmholtz Centre for Heavy Ion Research, Darmstadt (Germany); Zink, K [Institute of Medical Physics and Radiation Protection, University of Applied Sciences, Giessen (Germany); University Hospital Giessen-Marburg, Marburg (Germany)

    2016-06-15

    Purpose: In high energy photon therapy, several radiation protection issues result from photonuclear reactions. The activation of air - directly by photonuclear reactions as well as indirectly by capture of photoneutrons generated inside the linac head - is a major point of concern for the medical staff. The purpose of this study was to estimate the annual effective dose to medical workers due to activated air around a medical high energy electron linac by means of Monte Carlo simulations. Methods: The treatment head of a Varian Clinac in 18 MV-X mode as well as the surrounding concrete bunker were modeled and the radiation transport was simulated using the Monte Carlo code FLUKA, starting from the primary electron striking the bremsstrahlung target. The activation yields in air from photo-disintegration of O-16 and N-14 nuclei as well as from neutron capture on Ar-40 nuclei were obtained from the simulations. The activation build-up, radioactive decay and air ventilation were studied using a mathematical model. The annual effective dose to workers was estimated by using published isotope specific conversion factors. Results: The oxygen and nitrogen activation yields were in contrast to the argon activation yield found to be field size dependent. The impact of the treatment room ventilation on the different air activation products was investigated and quantified. An estimate with very conservative assumptions gave an annual effective dose to workers of < 1 mSv/a. Conclusion: From the results of this study it can be concluded that the contribution of air activation to the radiation exposure to medical workers should be negligible in modern photon therapy, especially when it is compared to the dose due to prompt neutrons and the activation of heavy solid materials such as the jaws and the collimators inside the linac head.

  2. Nanostructured energetic materials derived from sol-gel chemistry

    International Nuclear Information System (INIS)

    Simpson, R L; Tillotson, T M; Hrubesh, L W; Gash, A E

    2000-01-01

    Initiation and detonation properties are dramatically affected by an energetic material's microstructural properties. Sol-gel chemistry allows intimacy of mixing to be controlled and dramatically improved over existing methodologies. One material goal is to create very high power energetic materials which also have high energy densities. Using sol-gel chemistry we have made a nanostructured composite energetic material. Here a solid skeleton of fuel, based on resorcinol-formaldehyde, has nanocrystalline ammonium perchlorate, the oxidizer, trapped within its pores. At optimum stoichiometry it has approximately the energy density of HMX. Transmission electron microscopy indicated no ammonium perchlorate crystallites larger than 20 nm while near-edge soft x-ray absorption microscopy showed that nitrogen was uniformly distributed, at least on the scale of less than 80 nm. Small-angle neutron scattering studies were conducted on the material. Those results were consistent with historical ones for this class of nanostructured materials. The average skeletal primary particle size was on the order of 2.7 nm, while the nanocomposite showed the growth of small 1 nm size crystals of ammonium perchlorate with some clustering to form particles greater than 10 nm

  3. The problem of large samples. An activation analysis study of electronic waste material

    International Nuclear Information System (INIS)

    Segebade, C.; Goerner, W.; Bode, P.

    2007-01-01

    Large-volume instrumental photon activation analysis (IPAA) was used for the investigation of shredded electronic waste material. Sample masses from 1 to 150 grams were analyzed to obtain an estimate of the minimum sample size to be taken to achieve a representativeness of the results which is satisfactory for a defined investigation task. Furthermore, the influence of irradiation and measurement parameters upon the quality of the analytical results were studied. Finally, the analytical data obtained from IPAA and instrumental neutron activation analysis (INAA), both carried out in a large-volume mode, were compared. Only parts of the values were found in satisfactory agreement. (author)

  4. Four-electron transfer tandem tetracyanoquinodimethane for cathode-active material in lithium secondary battery

    Science.gov (United States)

    Kurimoto, Naoya; Omoda, Ryo; Mizumo, Tomonobu; Ito, Seitaro; Aihara, Yuichi; Itoh, Takahito

    2018-02-01

    Quinoid compounds are important candidates of organic active materials for lithium-ion batteries. However, its high solubility to organic electrolyte solutions and low redox potential are known as their major drawbacks. To circumvent these issues, we have designed and synthesized a tandem-tetracyanoquinonedimethane type cathode-active material, 11,11,12,12,13,13,14,14-octacyano-1,4,5,8-anthradiquinotetramethane (OCNAQ), that has four redox sites per molecule, high redox potential and suppressed solubility to electrolyte solution. Synthesized OCNAQ has been found to have two-step redox reactions by cyclic voltammetry, and each step consists of two-electron reactions. During charge-discharge tests using selected organic cathode-active materials with a lithium metal anode, the cell voltages obtained from OCNAQ are higher than those for 11,11-dicyanoanthraquinone methide (AQM) as expected, due to the strong electron-withdrawing effect of the cyano groups. Unfortunately, even with the use of the organic active material, the issue of dissolution to the electrolyte solution cannot be suppressed completely; however, appropriate choice of the electrolyte solutions, glyme-based electrolyte solutions in this study, give considerable improvement of the cycle retention (98% and 56% at 10 and 100 cycles at 0.5C, respectively). The specific capacity and energy density obtained in this study are 206 mAh g-1 and 554 mWh g-1 with respect to the cathode active material.

  5. Experimental study on the secondary emission (atomic and molecular ions, aggregates, electrons) induced by the bombardment of surfaces by means of energetic heavy ions (∼ MeV/u). Effects of the charge state of the projectiles

    International Nuclear Information System (INIS)

    Monart, B.

    1988-05-01

    The ionic and electronic emissions, induced by the sputtering of solid targets (organic and inorganic) with 1 MeV/u projectiles. The time-of-flight spectrometry is applied to the secondary emission analysis. The projectile velocity, the angle of attack (between the beam and the target), and the projectile's incident charge state, are taken into account. It is shown that the secondary emission depends on the charge of the incident ion and on the charge state changement in the material's bulk. A model, applying the theoretical calculations concerning the charge in the material's bulk, is proposed. The existence of an interaction depth, for the incident ion and the material, which depends on the secondary ions type and on the incident ion charge, is suggested. The calculated depth is about 200 angstroms for the aggregates ejected from a CsI target, sputtered with 14 Kr 18+ . The H + yield (coming from ∼ 10 angstroms) is used as a projectile charge probe, at the material surface. The experimental method allows, for the first time, the obtention of the equilibrium charge state in the condensed matter. The same method is applied to determine the non-equilibrium charges in the bulk of thin materials. The results show that, after leaving the material, the projectile presents a post-ionization state [fr

  6. Optimization of some eco-energetic systems

    International Nuclear Information System (INIS)

    Purica, I.; Pavelescu, M.; Stoica, M.

    1976-01-01

    An optimization problem of two eco-energetic systems is described. The first one is close to the actual eco-energetic system in Romania, while the second is a new one, based on nuclear energy as primary source and hydrogen energy as secondary source. The optimization problem solved is to find the optimal structure of the systems so that the objective functions adopted, namely unitary energy cost C and total pollution P, to be minimum at the same time. The problem can be modelated with a bimatrix cooperative mathematical game without side payments. We demonstrate the superiority of the new eco-energetic system. (author)

  7. Wakefields generated by electron beams passing through a waveguide loaded with a slightly dispersive active medium

    Directory of Open Access Journals (Sweden)

    Andrey V. Tyukhtin

    2007-05-01

    Full Text Available The wakefields of a relativistic electron beam passing through a waveguide loaded with an active medium with weak resonant dispersion are considered. For the calculations in this paper, the parameters of the medium are those of a solution of fullerene (C_{60} in a nematic liquid crystal that exhibits activity in the X-band. It is shown that several of the TM accelerating modes can be amplified for the geometries under consideration; structures in which higher order modes are amplified exhibit essential advantages as PASERs. In particular, the amplification of the highest mode occurs in a structure loaded with a rather thick active medium layer that maximizes the energy stored by the active medium.

  8. Detailed characteristics of radiation belt electrons revealed by CSSWE/REPTile measurements: Geomagnetic activity response and precipitation observation

    Science.gov (United States)

    Zhang, K.; Li, X.; Schiller, Q.; Gerhardt, D.; Zhao, H.; Millan, R.

    2017-08-01

    Earth's outer radiation belt electrons are highly dynamic. We study the detailed characteristics of relativistic electrons in the outer belt using measurements from the Colorado Student Space Weather Experiment (CSSWE) mission, a low Earth orbit (LEO) CubeSat, which traverses the radiation belt four times in one orbit ( 1.5 h) and has the advantage of measuring the dynamic activities of the electrons including their rapid precipitation. We focus on the measured electron response to geomagnetic activity for different energies to show that there are abundant sub-MeV electrons in the inner belt and slot region. These electrons are further enhanced during active times, while there is a lack of >1.63 MeV electrons in these regions. We also show that the variation of measured electron flux at LEO is strongly dependent on the local magnetic field strength, which is far from a dipole approximation. Moreover, a specific precipitation band, which happened on 19 January 2013, is investigated based on the conjunctive measurement of CSSWE, the Balloon Array for Radiation belt Relativistic Electron Losses, and one of the Polar Operational Environmental Satellites. In this precipitation band event, the net loss of the 0.58-1.63 MeV electrons (L = 3.5-6) is estimated to account for 6.8% of the total electron content.

  9. ENERGETIC FERMI/LAT GRB 100414A: ENERGETIC AND CORRELATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Urata, Yuji; Tsai, Patrick P. [Institute of Astronomy, National Central University, Chung-Li 32054, Taiwan (China); Huang, Kuiyun [Academia Sinica Institute of Astronomy and Astrophysics, Taipei 106, Taiwan (China); Yamaoka, Kazutaka [Department of Physics and Mathematics, Aoyama Gakuin University, 5-10-1, Fuchinobe, Sayamihara 229-8558 (Japan); Tashiro, Makoto S., E-mail: urata@astro.ncu.edu.tw [Department of Physics, Saitama University, Shimo-Okubo, Saitama 338-8570 (Japan)

    2012-03-20

    This study presents multi-wavelength observational results for energetic GRB 100414A with GeV photons. The prompt spectral fitting using Suzaku/WAM data yielded spectral peak energies of E{sup src}{sub peak} of 1458.7{sup +132.6}{sub -106.6} keV and E{sub iso} of 34.5{sup +2.0}{sub -1.8} Multiplication-Sign 10{sup 52} erg with z = 1.368. The optical afterglow light curves between 3 and 7 days were effectively fitted according to a simple power law with a temporal index of {alpha} = -2.6 {+-} 0.1. The joint light curve with earlier Swift/UVOT observations yields a temporal break at 2.3 {+-} 0.2 days. This was the first Fermi/LAT detected event that demonstrated the clear temporal break in the optical afterglow. The jet opening angle derived from this temporal break was 5.{sup 0}8, consistent with those of other well-observed long gamma-ray bursts (GRBs). The multi-wavelength analyses in this study showed that GRB 100414A follows E{sup src}{sub peak}-E{sub iso} and E{sup src}{sub peak}-E{sub {gamma}} correlations. The late afterglow revealed a flatter evolution with significant excesses at 27.2 days. The most straightforward explanation for the excess is that GRB 100414A was accompanied by a contemporaneous supernova. The model light curve based on other GRB-SN events is marginally consistent with that of the observed light curve.

  10. Energetic Nitrogen Ions within the Inner Magnetosphere of Saturn

    Science.gov (United States)

    Sittler, E. C.; Johnson, R. E.; Richardson, J. D.; Jurac, S.; Moore, M.; Cooper, J. F.; Mauk, B. H.; Smith, H. T.; Michael, M.; Paranicus, C.; Armstrong, T. P.; Tsurutani, B.; Connerney, J. E. P.

    2003-05-01

    Titan's interaction with Saturn's magnetosphere will result in the energetic ejection of atomic nitrogen atoms into Saturn's magnetosphere due to dissociation of N2 by electrons, ions, and UV photons. The ejection of N atoms into Saturn's magnetosphere will form a nitrogen torus around Saturn with mean density of about 4 atoms/cm3 with source strength of 4.5x1025 atoms/sec. These nitrogen atoms are ionized by photoionization, electron impact ionization and charge exchange reactions producing an N+ torus of 1-4 keV suprathermal ions centered on Titan's orbital position. We will show Voyager plasma observations that demonstrate presence of a suprathermal ion component within Saturn's outer magnetosphere. The Voyager LECP data also reported the presence of inward diffusing energetic ions from the outer magnetosphere of Saturn, which could have an N+ contribution. If so, when one conserves the first and second adiabatic invariant the N+ ions will have energies in excess of 100 keV at Dione's L shell and greater than 400 keV at Enceladus' L shell. Energetic charged particle radial diffusion coefficients are also used to constrain the model results. But, one must also consider the solar wind as another important source of keV ions, in the form of protons and alpha particles, for Saturn's outer magnetosphere. Initial estimates indicate that a solar wind source could dominate in the outer magnetosphere, but various required parameters for this estimate are highly uncertain and will have to await Cassini results for confirmation. We show that satellite sweeping and charged particle precipitation within the middle and outer magnetosphere will tend to enrich N+ ions relative to protons within Saturn's inner magnetosphere as they diffuse radially inward for radial diffusion coefficients that do not violate observations. Charge exchange reactions within the inner magnetosphere can be an important loss mechanism for O+ ions, but to a lesser degree for N+ ions. Initial LECP

  11. Energetic radiation produced during rocket-triggered lightning.

    Science.gov (United States)

    Dwyer, Joseph R; Uman, Martin A; Rassoul, Hamid K; Al-Dayeh, Maher; Caraway, Lee; Jerauld, Jason; Rakov, Vladimir A; Jordan, Douglas M; Rambo, Keith J; Corbin, Vincent; Wright, Brian

    2003-01-31

    Using a NaI(Tl) scintillation detector designed to operate in electrically noisy environments, we observed intense bursts of energetic radiation (> 10 kiloelectron volts) during the dart leader phase of rocket-triggered lightning, just before and possibly at the very start of 31 out of the 37 return strokes measured. The bursts had typical durations of less than 100 microseconds and deposited many tens of megaelectron volts into the detector. These results provide strong evidence that the production of runaway electrons is an important process during lightning.

  12. Studies of energetic ion confinement during fishbone events in PDX

    International Nuclear Information System (INIS)

    Strachan, J.D.; Grek, B.; Heidbrink, W.; Johnson, D.; Kaye, S.; Kugel, H.; LeBlanc, B.; McGuire, K.

    1984-11-01

    The 2.5-MeV neutron emission from the beam-target d(d,n,) 3 He fusion reaction has been examined for all PDX deuterium plasmas which were heated by deuterium neutral beams. The magnitude of the emission was found to scale classically and increase with T/sub e//sup 3/2/ as expected when electron drag is the primary energy degradation mechanism. The time evolution of the neutron emission through fishbone events was measured and used to determine the confinement properties of the energetic beam ions. Many of the experimental results are predicted by the Mode Particle Pumping theory

  13. Effect of electron beam irradiation on conidial germination activity and pathogenicity of Botrytis cinerea

    International Nuclear Information System (INIS)

    Zhang Ting; Qiao Yongjin; Chen Zhaoliang

    2011-01-01

    Conidia of Botrytis cinerea were irradiated by electron beam at 0.5, 1.0, 2.0 and 3.0 kGy. The influence of electron beam on the activities of conidial germination and pathogenicity at the temperatures of 5 ℃ and 25 ℃ were tested, respectively. The results showed that the electron beam could inhibit germination of conidia and the length of germ tube of Botrytis cinerea, and delay the germination time. It could also decrease the pathogenicity obviously and higher irradiation dose showed stronger effects. Compared with control, the complete germination time of conidia extended to 5 and 9 d at the cultivate temperatures of 25 ℃ and 5 ℃, after 2 kGy of irradiation, and the germination rate was reduced 46.57% and 33.68%, respectively. The inhibition rates of germ tube were 25.12% and 74.29% when cultured 24 h. The pathogenicity of Botrytis cinerea to strawberry was reduced significantly. After 2.0 kGy irradiation and cultivate at 25 ℃ for 2 d, the disease index was 4.17 and it decreased to 15.28 after cultivation of 5 ℃ for 15 d. Electron beam treatment could inhibit the spore germination and germ tube elongation of Botrytis cinerea significantly, delayed the germination time, and reduced its pathogenicity, the higher the dose, the effect was more obvious. (authors)

  14. Electronic Structure Control of Tungsten Oxide Activated by Ni for Ultrahigh-Performance Supercapacitors.

    Science.gov (United States)

    Meng, Tian; Kou, Zongkui; Amiinu, Ibrahim Saana; Hong, Xufeng; Li, Qingwei; Tang, Yongfu; Zhao, Yufeng; Liu, Shaojun; Mai, Liqiang; Mu, Shichun

    2018-04-17

    Tuning the electron structure is of vital importance for designing high active electrode materials. Here, for boosting the capacitive performance of tungsten oxide, an atomic scale engineering approach to optimize the electronic structure of tungsten oxide by Ni doping is reported. Density functional theory calculations disclose that through Ni doping, the density of state at Fermi level for tungsten oxide can be enhanced, thus promoting its electron transfer. When used as electrode of supercapacitors, the obtained Ni-doped tungsten oxide with 4.21 at% Ni exhibits an ultrahigh mass-specific capacitance of 557 F g -1 at the current density of 1 A g -1 and preferable durability in a long-term cycle test. To the best of knowledge, this is the highest supercapacitor performance reported so far in tungsten oxide and its composites. The present strategy demonstrates the validity of the electronic structure control in tungsten oxide via introducing Ni atoms for pseudocapacitors, which can be extended to other related fields as well. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Effects of Home Access to Active Videogames on Child Self-Esteem, Enjoyment of Physical Activity, and Anxiety Related to Electronic Games: Results from a Randomized Controlled Trial.

    Science.gov (United States)

    Abbott, Rebecca A; Smith, Anne J; Howie, Erin K; Pollock, Clare; Straker, Leon

    2014-08-01

    Active-input videogames could provide a useful conduit for increasing physical activity by improving a child's self-confidence, physical activity enjoyment, and reducing anxiety. Therefore this study evaluated the impact of (a) the removal of home access to traditional electronic games or (b) their replacement with active-input videogames, on child self-perception, enjoyment of physical activity, and electronic game use anxiety. This was a crossover, randomized controlled trial, conducted over a 6-month period in participants' family homes in metropolitan Perth, Australia, from 2007 to 2010. Children 10-12 years old were recruited through school and community media. Of 210 children who were eligible, 74 met inclusion criteria, and 8 withdrew, leaving 66 children (33 girls) for analysis. A counterbalanced randomized order of three conditions sustained for 8 weeks each: No home access to electronic games, home access to traditional electronic games, and home access to active-input electronic games. Perception of self-esteem (Harter's Self Perception Profile for Children), enjoyment of physical activity (Physical Activity Enjoyment Scale questionnaire), and anxiety toward electronic game use (modified Loyd and Gressard Computer Anxiety Subscale) were assessed. Compared with home access to traditional electronic games, neither removal of all electronic games nor replacement with active-input games resulted in any significant change to child self-esteem, enjoyment of physical activity, or anxiety related to electronic games. Although active-input videogames have been shown to be enjoyable in the short term, their ability to impact on psychological outcomes is yet to be established.

  16. Conductance and activation energy for electron transport in series and parallel intramolecular circuits.

    Science.gov (United States)

    Hsu, Liang-Yan; Wu, Ning; Rabitz, Herschel

    2016-11-30

    We investigate electron transport through series and parallel intramolecular circuits in the framework of the multi-level Redfield theory. Based on the assumption of weak monomer-bath couplings, the simulations depict the length and temperature dependence in six types of intramolecular circuits. In the tunneling regime, we find that the intramolecular circuit rule is only valid in the weak monomer coupling limit. In the thermally activated hopping regime, for circuits based on two different molecular units M a and M b with distinct activation energies E act,a > E act,b , the activation energies of M a and M b in series are nearly the same as E act,a while those in parallel are nearly the same as E act,b . This study gives a comprehensive description of electron transport through intramolecular circuits from tunneling to thermally activated hopping. We hope that this work can motivate additional studies to design intramolecular circuits based on different types of building blocks, and to explore the corresponding circuit laws and the length and temperature dependence of conductance.

  17. Light-Enhanced Antibacterial Activity of Graphene Oxide, Mainly via Accelerated Electron Transfer.

    Science.gov (United States)

    Chong, Yu; Ge, Cuicui; Fang, Ge; Wu, Renfei; Zhang, He; Chai, Zhifang; Chen, Chunying; Yin, Jun-Jie

    2017-09-05

    Before graphene derivatives can be exploited as next-generation antimicrobials, we must understand their behavior under environmental conditions. Here, we demonstrate how exposure to simulated sunlight significantly enhances the antibacterial activity of graphene oxide (GO) and reveal the underlying mechanism. Our measurements of reactive oxygen species (ROS) showed that only singlet oxygen ( 1 O 2 ) is generated by GO exposed to simulated sunlight, which contributes only slightly to the oxidation of antioxidant biomolecules. Unexpectedly, we find the main cause of oxidation is light-induced electron-hole pairs generated on the surface of GO. These light-induced electrons promote the reduction of GO, introducing additional carbon-centered free radicals that may also enhance the antibacterial activities of GO. We conclude that GO-mediated oxidative stress mainly is ROS-independent; simulated sunlight accelerates the transfer of electrons from antioxidant biomolecules to GO, thereby destroying bacterial antioxidant systems and causing the reduction of GO. Our insights will help support the development of graphene for antibacterial applications.

  18. Misfit Strain in Superlattices Controlling the Electron-Lattice Interaction via Micro strain in Active Layers

    International Nuclear Information System (INIS)

    Poccia, N.; Ricci, A.; Bianconi, N.

    2010-01-01

    High-temperature superconductivity (HTS) emerges in quite different electronic materials: cuprates, diborides, and iron-pnictide superconductors. Looking for unity in the diversity we find in all these materials a common lattice architecture: they are practical realizations of heterostructures at atomic limit made of superlattices of metallic active layers intercalated by spacers as predicted in 1993 by one of us. The multilayer architecture is the key feature for the presence of electronic topological transitions where the Fermi surface of one of the subbands changes dimensionality. The superlattice misfit strain η between the active and spacer layers is shown to be a key variable to drive the system to the highest critical temperature Tc that occurs at a particular point of the 3D phase diagram Tc(θ, η) where d is the charge transfer or doping. The plots of Tc as a function of misfit strain at constant charge transfer in cuprates show a first-order quantum critical phase transition where an itinerant striped magnetic phase competes with superconductivity in the proximity of a structural phase transition, that is, associated with an electronic topological transition. The shape resonances in these multi gap superconductors is associated with the maximum Tc.

  19. Hydro energetic inventory study from Chapecozinho river

    International Nuclear Information System (INIS)

    Pimenta, S.C.; Sureck, M.A.A.; Nascimento, P.R.; Kawasaki, M.; Silva Felipe, R. da.

    1990-01-01

    The Hydro energetic Inventory Study in Chapecozinho River Basin, Brazil is described, comparing the proposed results in 1979 with the actual review in 1989. An analysis for solution the socio-economic and environment problems is also presented. (author)

  20. Energetic particle observations at the subsolar magnetopause

    Directory of Open Access Journals (Sweden)

    A. A. Eccles

    Full Text Available The pitch-angle distributions (PAD of energetic particles are examined as the ISEE-1 satellite crosses the Earth’s magnetopause near the subsolar point. The investigation focuses on the possible existence of a particular type of distribution that would be associated with a source of energetic particles in the high-latitude magnetosphere. PADs, demonstrating broad, persistent field-aligned fluxes filling a single hemisphere (upper/northern or lower/southern, were observed just sunward of the magnetopause current layer for an extended period of many minutes. These distributions are a direct prediction of a possible source of energetic particles located in the high altitude dayside cusp and we present five examples in detail of the three-dimensional particle distributions to demonstrate their existence. From these results, other possible causes of such PADs are examined.

    Key words. Magnetospheric physics (energetic particles, precipitating; magnetopause, cusp and boundary layers; magnetospheric configuration and dynamics

  1. Global Positioning System (GPS) Energetic Particle Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Energetic particle data from the CXD and BDD instrument on the GPS constellation are available to the space weather research community. The release of these data...

  2. Modeling Thermal Ignition of Energetic Materials

    National Research Council Canada - National Science Library

    Gerri, Norman J; Berning, Ellen

    2004-01-01

    This report documents an attempt to computationally simulate the mechanics and thermal regimes created when a threat perforates an armor envelope and comes in contact with stowed energetic material...

  3. Organization of the national energetic institutions

    International Nuclear Information System (INIS)

    Waltenberg, D.A.M.

    1983-01-01

    This text broaches, in a critical pourt of view, the organization of national energetic institutions, the need of a law revision, the problem of the rising of tariff and shows the decisions of GC01 [pt

  4. Pitch angle scattering of an energetic magnetized particle by a circularly polarized electromagnetic wave

    International Nuclear Information System (INIS)

    Bellan, P. M.

    2013-01-01

    The interaction between a circularly polarized wave and an energetic gyrating particle is described using a relativistic pseudo-potential that is a function of the frequency mismatch. Analysis of the pseudo-potential provides a means for interpreting numerical results. The pseudo-potential profile depends on the initial mismatch, the normalized wave amplitude, and the initial angle between the wave magnetic field and the particle perpendicular velocity. For zero initial mismatch, the pseudo-potential consists of only one valley, but for finite mismatch, there can be two valleys separated by a hill. A large pitch angle scattering of the energetic electron can occur in the two-valley situation but fast scattering can also occur in a single valley. Examples relevant to magnetospheric whistler waves show that the energetic electron pitch angle can be deflected 5°towards the loss cone when transiting a 10 ms long coherent wave packet having realistic parameters.

  5. Plasma and energetic particle structure upstream of a quasi-parallel interplanetary shock

    Science.gov (United States)

    Kennel, C. F.; Scarf, F. L.; Coroniti, F. V.; Russell, C. T.; Wenzel, K.-P.; Sanderson, T. R.; Van Nes, P.; Smith, E. J.; Tsurutani, B. T.; Scudder, J. D.

    1984-01-01

    ISEE 1, 2 and 3 data from 1978 on interplanetary magnetic fields, shock waves and particle energetics are examined to characterize a quasi-parallel shock. The intense shock studied exhibited a 640 km/sec velocity. The data covered 1-147 keV protons and electrons and ions with energies exceeding 30 keV in regions both upstream and downstream of the shock, and also the magnitudes of ion-acoustic and MHD waves. The energetic particles and MHD waves began being detected 5 hr before the shock. Intense halo electron fluxes appeared ahead of the shock. A closed magnetic field structure was produced with a front end 700 earth radii from the shock. The energetic protons were cut off from the interior of the magnetic bubble, which contained a markedly increased density of 2-6 keV protons as well as the shock itself.

  6. Automatic prediction of rheumatoid arthritis disease activity from the electronic medical records.

    Directory of Open Access Journals (Sweden)

    Chen Lin

    Full Text Available We aimed to mine the data in the Electronic Medical Record to automatically discover patients' Rheumatoid Arthritis disease activity at discrete rheumatology clinic visits. We cast the problem as a document classification task where the feature space includes concepts from the clinical narrative and lab values as stored in the Electronic Medical Record.The Training Set consisted of 2792 clinical notes and associated lab values. Test Set 1 included 1749 clinical notes and associated lab values. Test Set 2 included 344 clinical notes for which there were no associated lab values. The Apache clinical Text Analysis and Knowledge Extraction System was used to analyze the text and transform it into informative features to be combined with relevant lab values.Experiments over a range of machine learning algorithms and features were conducted. The best performing combination was linear kernel Support Vector Machines with Unified Medical Language System Concept Unique Identifier features with feature selection and lab values. The Area Under the Receiver Operating Characteristic Curve (AUC is 0.831 (σ = 0.0317, statistically significant as compared to two baselines (AUC = 0.758, σ = 0.0291. Algorithms demonstrated superior performance on cases clinically defined as extreme categories of disease activity (Remission and High compared to those defined as intermediate categories (Moderate and Low and included laboratory data on inflammatory markers.Automatic Rheumatoid Arthritis disease activity discovery from Electronic Medical Record data is a learnable task approximating human performance. As a result, this approach might have several research applications, such as the identification of patients for genome-wide pharmacogenetic studies that require large sample sizes with precise definitions of disease activity and response to therapies.

  7. Electron-cyclotron-resonant-heated electron distribution functions

    International Nuclear Information System (INIS)

    Matsuda, Y.; Nevins, W.M.; Cohen, R.H.

    1981-01-01

    Recent studies at Lawrence Livermore National Laboratory (LLNL) with a bounce-averaged Fokker-Planck code indicate that the energetic electron tail formed by electron-cyclotron resonant heating (ECRH) at the second harmonic is not Maxwellian. We present the results of our bounce-averaged Fokker-Planck code along with some simple analytic models of hot-electron distribution functions

  8. Nuclear energetics all over the world

    International Nuclear Information System (INIS)

    Wojcik, T.

    2000-01-01

    The actual state and tendencies of nuclear power further development for different world regions have been presented and discussed. The problem of safety of energetic nuclear reactors, radioactive waste management and related problems have been discussed in respect of regulations in different countries. The economical aspects of nuclear energetics in comparison with different fossil fuel power plants exploitation costs has been presented as well. The official state of international organizations (IAEA, WANO, HASA etc.) have been also shown in respect to subject presented

  9. Metagenomic insight into methanogenic reactors promoting direct interspecies electron transfer via granular activated carbon.

    Science.gov (United States)

    Park, Jeong-Hoon; Park, Jong-Hun; Je Seong, Hoon; Sul, Woo Jun; Jin, Kang-Hyun; Park, Hee-Deung

    2018-07-01

    To provide insight into direct interspecies electron transfer via granular activated carbon (GAC), the effect of GAC supplementation on anaerobic digestion was evaluated. Compared to control samples, the GAC supplementation increased the total amount of methane production and its production rate by 31% and 72%, respectively. 16S rDNA sequencing analysis revealed a shift in the archaeal community composition; the Methanosarcina proportion decreased 17%, while the Methanosaeta proportion increased 5.6%. Metagenomic analyses based on shotgun sequencing demonstrated that the abundance of pilA and omcS genes belonging to Geobacter species decreased 69.4% and 29.4%, respectively. Furthermore, the analyses suggested a carbon dioxide reduction pathway rather than an acetate decarboxylation pathway for methane formation. Taken together, these results suggest that GAC improved methane production performance by shifting the microbial community and altering functional genes associated with direct interspecies electron transfer via conductive materials. Copyright © 2018 Elsevier Ltd. All rights reserved.

  10. The minimal energetic requirement of sustained awareness after brain injury

    DEFF Research Database (Denmark)

    Stender, Johan; Mortensen, Kristian Nygaard; Thibaut, Aurore

    2016-01-01

    of glucose has been proposed as an indicator of consciousness [2 and 3]. Likewise, FDG-PET may contribute to the clinical diagnosis of disorders of consciousness (DOCs) [4 and 5]. However, current methods are non-quantitative and have important drawbacks deriving from visually guided assessment of relative...... changes in brain metabolism [4]. We here used FDG-PET to measure resting state brain glucose metabolism in 131 DOC patients to identify objective quantitative metabolic indicators and predictors of awareness. Quantitation of images was performed by normalizing to extracerebral tissue. We show that 42......% of normal cortical activity represents the minimal energetic requirement for the presence of conscious awareness. Overall, the cerebral metabolic rate accounted for the current level, or imminent return, of awareness in 94% of the patient population, suggesting a global energetic threshold effect...

  11. Antimycobacterial and Photosynthetic Electron Transport Inhibiting Activity of Ring-Substituted 4-Arylamino-7-Chloroquinolinium Chlorides

    Directory of Open Access Journals (Sweden)

    Alois Cizek

    2013-09-01

    Full Text Available In this study, a series of twenty-five ring-substituted 4-arylamino-7-chloroquinolinium chlorides were prepared and characterized. The compounds were tested for their activity related to inhibition of photosynthetic electron transport (PET in spinach (Spinacia oleracea L. chloroplasts and also primary in vitro screening of the synthesized compounds was performed against mycobacterial species. 4-[(2-Bromophenylamino]-7-chloroquinolinium chloride showed high biological activity against M. marinum, M. kansasii, M. smegmatis and 7-chloro-4-[(2-methylphenylamino]quinolinium chloride demonstrated noteworthy biological activity against M. smegmatis and M. avium subsp. paratuberculosis. The most effective compounds demonstrated quite low toxicity (LD50 > 20 μmol/L against the human monocytic leukemia THP-1 cell line within preliminary in vitro cytotoxicity screening. The tested compounds were found to inhibit PET in photosystem II. The PET-inhibiting activity expressed by IC50 value of the most active compound 7-chloro-4-[(3-trifluoromethylphenylamino]quinolinium chloride was 27 μmol/L and PET-inhibiting activity of ortho-substituted compounds was significantly lower than this of meta- and para-substituted ones. The structure-activity relationships are discussed for all compounds.

  12. CIRCUMSOLAR ENERGETIC PARTICLE DISTRIBUTION ON 2011 NOVEMBER 3

    Energy Technology Data Exchange (ETDEWEB)

    Gómez-Herrero, R.; Blanco, J.J.; Rodríguez-Pacheco, J. [SRG, Universidad de Alcalá, E-28871 Alcalá de Henares (Spain); Dresing, N.; Klassen, A.; Heber, B.; Banjac, S. [IEAP, Christian-Albrechts-Universität zu Kiel, D-24118 Kiel (Germany); Lario, D. [The Johns Hopkins University, Applied Physics Laboratory, Laurel, MD 20723 (United States); Agueda, N. [Departament d' Astronomia i Meteorologia. Institut de Ciències del Cosmos. Universitat de Barcelona, E-08028 Barcelona (Spain); Malandraki, O. E., E-mail: raul.gomezh@uah.es [IAASARS, National Observatory of Athens, GR-15236 Penteli (Greece)

    2015-01-20

    Late on 2011 November 3, STEREO-A, STEREO-B, MESSENGER, and near-Earth spacecraft observed an energetic particle flux enhancement. Based on the analysis of in situ plasma and particle observations, their correlation with remote sensing observations, and an interplanetary transport model, we conclude that the particle increases observed at multiple locations had a common single-source active region and the energetic particles filled a very broad region around the Sun. The active region was located at the solar backside (as seen from Earth) and was the source of a large flare, a fast and wide coronal mass ejection, and an EIT wave, accompanied by type II and type III radio emission. In contrast to previous solar energetic particle events showing broad longitudinal spread, this event showed clear particle anisotropies at three widely separated observation points at 1 AU, suggesting direct particle injection close to the magnetic footpoint of each spacecraft, lasting for several hours. We discuss these observations and the possible scenarios explaining the extremely broad particle spread for this event.

  13. Low temperature electron beam irradiation effects on the lactate dehydrogenase activity

    International Nuclear Information System (INIS)

    Catana, D.; Hategan, Alina; Oproiu, C.; Popescu, Alina; Hategan, Dora; Morariu, V. V.

    1998-01-01

    The direct and indirect effects of 5 MeV electron beam irradiation in the range 0-400 Gy at 20 deg. C, -3 deg. C and -196 deg. C on the global enzymatic activity of lactate dehydrogenase (LDH) have been studied. Our results showed a monoexponential decrease in the enzymatic activity of irradiated LDH at all irradiation temperatures independently of direct or indirect action of radiation. The temperature gradient used to lower the temperature of the samples to -196 deg. C drastically influences the results. Our data suggest that freeze-thawing in two steps down to -196 deg. C make LDH insensitive to irradiation, while one step freeze-thawing procedure results in a gradual activity loss with increasing dose irradiation. This data can be interpreted in terms of different conformational changes during the particular freeze-thawing process. (authors)

  14. Development of microalgae biomaterials with enhanced antioxidant activity using electron beam

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Younghwa; Park, Hyunjin; Choi, Soojeong; Lee, Jaehwa [Silla Univ., Busan (Korea, Republic of)

    2013-07-01

    By increasing the antioxidant products (e. g. antioxidant enzyme, carotenoid, phycobiliproteins, chlorophyll, lipid phenolic compounds, etc.) in microalgae, it could be useful for industry. In this study, mutants of fresh water microalgae Arthrospira platensis (A. platensis) by high energy electron beam were isolated and characterized. Those selected mutants showed higher growth rate than parental strain. The antioxidant enzyme activity (SOD and POD), flavonoid, phenolic compound and phycocyanin of mutants were increased about 2 times compared to wild type. Moreover, DPPH radical scavenging activity was increased about 20%. Microalgae species with improved growth rate and enhanced active compounds make the commercial process more feasible in industry. Using microalgae mutants with increased antioxidant products, it is useful to develop microalgae biomaterials for neutraceuticals.

  15. Development of microalgae biomaterials with enhanced antioxidant activity using electron beam

    International Nuclear Information System (INIS)

    Kim, Younghwa; Park, Hyunjin; Choi, Soojeong; Lee, Jaehwa

    2013-01-01

    By increasing the antioxidant products (e. g. antioxidant enzyme, carotenoid, phycobiliproteins, chlorophyll, lipid phenolic compounds, etc.) in microalgae, it could be useful for industry. In this study, mutants of fresh water microalgae Arthrospira platensis (A. platensis) by high energy electron beam were isolated and characterized. Those selected mutants showed higher growth rate than parental strain. The antioxidant enzyme activity (SOD and POD), flavonoid, phenolic compound and phycocyanin of mutants were increased about 2 times compared to wild type. Moreover, DPPH radical scavenging activity was increased about 20%. Microalgae species with improved growth rate and enhanced active compounds make the commercial process more feasible in industry. Using microalgae mutants with increased antioxidant products, it is useful to develop microalgae biomaterials for neutraceuticals

  16. Pitch angle distributions of electrons at dipolarization sites during geomagnetic activity: THEMIS observations

    Science.gov (United States)

    Wang, Kaiti; Lin, Ching-Huei; Wang, Lu-Yin; Hada, Tohru; Nishimura, Yukitoshi; Turner, Drew L.; Angelopoulos, Vassilis

    2014-12-01

    Changes in pitch angle distributions of electrons with energies from a few eV to 1 MeV at dipolarization sites in Earth's magnetotail are investigated statistically to determine the extent to which adiabatic acceleration may contribute to these changes. Forty-two dipolarization events from 2008 and 2009 observed by Time History of Events and Macroscale Interactions during Substorms probes covering the inner plasma sheet from 8 RE to 12 RE during geomagnetic activity identified by the AL index are analyzed. The number of observed events with cigar-type distributions (peaks at 0° and 180°) decreases sharply below 1 keV after dipolarization because in many of these events, electron distributions became more isotropized. From above 1 keV to a few tens of keV, however, the observed number of cigar-type events increases after dipolarization and the number of isotropic events decreases. These changes can be related to the ineffectiveness of Fermi acceleration below 1 keV (at those energies, dipolarization time becomes comparable to electron bounce time). Model-calculated pitch angle distributions after dipolarization with the effect of betatron and Fermi acceleration tested indicate that these adiabatic acceleration mechanisms can explain the observed patterns of event number changes over a large range of energies for cigar events and isotropic events. Other factors still need to be considered to assess the observed increase in cigar events around 2 keV. Indeed, preferential directional increase/loss of electron fluxes, which may contribute to the formation of cigar events, was observed. Nonadiabatic processes to accelerate electrons in a parallel direction may also be important for future study.

  17. Structure of Energetic Particle Mediated Shocks Revisited

    International Nuclear Information System (INIS)

    Mostafavi, P.; Zank, G. P.; Webb, G. M.

    2017-01-01

    The structure of collisionless shock waves is often modified by the presence of energetic particles that are not equilibrated with the thermal plasma (such as pickup ions [PUIs] and solar energetic particles [SEPs]). This is relevant to the inner and outer heliosphere and the Very Local Interstellar Medium (VLISM), where observations of shock waves (e.g., in the inner heliosphere) show that both the magnetic field and thermal gas pressure are less than the energetic particle component pressures. Voyager 2 observations revealed that the heliospheric termination shock (HTS) is very broad and mediated by energetic particles. PUIs and SEPs contribute both a collisionless heat flux and a higher-order viscosity. We show that the incorporation of both effects can completely determine the structure of collisionless shocks mediated by energetic ions. Since the reduced form of the PUI-mediated plasma model is structurally identical to the classical cosmic ray two-fluid model, we note that the presence of viscosity, at least formally, eliminates the need for a gas sub-shock in the classical two-fluid model, including in that regime where three are possible. By considering parameters upstream of the HTS, we show that the thermal gas remains relatively cold and the shock is mediated by PUIs. We determine the structure of the weak interstellar shock observed by Voyager 1 . We consider the inclusion of the thermal heat flux and viscosity to address the most general form of an energetic particle-thermal plasma two-fluid model.

  18. Structure of Energetic Particle Mediated Shocks Revisited

    Energy Technology Data Exchange (ETDEWEB)

    Mostafavi, P.; Zank, G. P. [Department of Space Science, University of Alabama in Huntsville, Huntsville, AL 35899 (United States); Webb, G. M. [Center for Space Plasma and Aeronomic Research (CSPAR), University of Alabama in Huntsville, Huntsville, AL 35899 (United States)

    2017-05-20

    The structure of collisionless shock waves is often modified by the presence of energetic particles that are not equilibrated with the thermal plasma (such as pickup ions [PUIs] and solar energetic particles [SEPs]). This is relevant to the inner and outer heliosphere and the Very Local Interstellar Medium (VLISM), where observations of shock waves (e.g., in the inner heliosphere) show that both the magnetic field and thermal gas pressure are less than the energetic particle component pressures. Voyager 2 observations revealed that the heliospheric termination shock (HTS) is very broad and mediated by energetic particles. PUIs and SEPs contribute both a collisionless heat flux and a higher-order viscosity. We show that the incorporation of both effects can completely determine the structure of collisionless shocks mediated by energetic ions. Since the reduced form of the PUI-mediated plasma model is structurally identical to the classical cosmic ray two-fluid model, we note that the presence of viscosity, at least formally, eliminates the need for a gas sub-shock in the classical two-fluid model, including in that regime where three are possible. By considering parameters upstream of the HTS, we show that the thermal gas remains relatively cold and the shock is mediated by PUIs. We determine the structure of the weak interstellar shock observed by Voyager 1 . We consider the inclusion of the thermal heat flux and viscosity to address the most general form of an energetic particle-thermal plasma two-fluid model.

  19. CdWO4 polymorphs: Selective preparation, electronic structures, and photocatalytic activities

    International Nuclear Information System (INIS)

    Yan, Tingjiang; Li, Liping; Tong, Wenming; Zheng, Jing; Wang, Yunjian; Li, Guangshe

    2011-01-01

    This work explored the selective synthesis of polymorphs of CdWO 4 in either tetragonal or monoclinic phase by optimizing the experimental parameters. Systematic characterization indicated that both polymorphs possessed similar spherical morphologies but different structural building blocks. Electronic structures calculations for both polymorphs demonstrated the same constructions of conduction band or valence band, while the conduction band widths of both polymorphs were quite different. Both CdWO 4 polymorphs exhibited good photocatalytic activity for degradation of methyl orange under UV light irradiation. When comparing to some other well-known tungstate oxide materials, the photocatalytic activity was found to follow such a consequence, monoclinic CdWO 4 ∼monoclinic ZnWO 4 >tetragonal CdWO 4 >tetragonal CaWO 4 . The specific photocatalytic activity of monoclinic CdWO 4 was even higher than that of commercial TiO 2 photocatalyst (Degussa P25). The increased activity from the tetragonal CdWO 4 to the monoclinic was consistent with the trend of the decreased symmetry, and this could be explained in terms of the geometric structures and electronic structures for both polymorphs. -- Graphical abstract: Monoclinic CdWO 4 exhibited a much higher photocatalytic activity than the tetragonal form owing to the lower symmetry, more distorted geometric structure, and the dispersive band configuration. Display Omitted Research highlights: → Polymorphs of CdWO 4 in either tetragonal or monoclinic phase were selectively synthesized. → Both polymorphs possessed similar spherical morphologies, while the relevant structural building blocks were different. → Photocatalytic activities of CdWO 4 polymorphs depended strongly on the symmetry, geometric structure, as well as band configuration.

  20. Reactive thermal waves in energetic materials

    Energy Technology Data Exchange (ETDEWEB)

    Hill, Larry G [Los Alamos National Laboratory

    2009-01-01

    Reactive thermal waves (RTWs) arise in several energetic material applications, including self-propagating high-temperature synthesis (SHS), high explosive cookoff, and the detonation of heterogeneous explosives. In this paper I exmaine ideal RTWs, by which I mean that (1) material motion is neglected, (2) the state dependence of reaction is Arrhenius in the temperature, and (3) the reaction rate is modulated by an arbitrary mass-fraction-based reaction progress function. Numerical simulations demonstrate that one's natural intuition, which is based mainly upon experience with inert materials and which leads one to expect diffusion processes to become relatively slow after a short time period, is invalid for high energy, state-sensitive reactive systems. Instead, theory predicts that RTWs can propagate at very high speeds. This result agrees with estimates for detonating heterogeneous explosives, which indicate that RTWs must spread from hot-spot nucleation sites at rates comparable to the detonation speed in order to produce experimentally-observed reaction zone thicknesses. Using dimensionless scaling and further invoking the high activation energy approximation, I obtain an analytic formula for the steady plane RTW speed from numerical calculations. I then compute the RTW speed for real explosives, and discuss aspects of their behavior.

  1. The patients' active role in managing a personal electronic health record: a qualitative analysis.

    Science.gov (United States)

    Baudendistel, Ines; Winkler, Eva; Kamradt, Martina; Brophy, Sarah; Längst, Gerda; Eckrich, Felicitas; Heinze, Oliver; Bergh, Bjoern; Szecsenyi, Joachim; Ose, Dominik

    2015-09-01

    The complexity of illness and cross-sectoral health care pose challenges for patients with colorectal cancer and their families. Within a patient-centered care paradigm, it is vital to give patients the opportunity to play an active role. Prospective users' attitudes regarding the patients' role in the context of a patient-controlled electronic health record (PEPA) were explored. A qualitative study across regional health care settings and health professions was conducted. Overall, 10 focus groups were performed collecting views of 3 user groups: patients with colorectal cancer (n = 12) and representatives from patient support groups (n = 2), physicians (n = 17), and other health care professionals (HCPs) (n = 16). Data were audio- and videotaped, transcribed verbatim and thematically analyzed using qualitative content analysis. The patients' responsibility as a gatekeeper and access manager was at the center of the focus group discussions, although HCPs addressed aspects that would limit patients taking an active role (e.g., illness related issues). Despite expressed concerns, PEPAs possibility to enhance personal responsibility was seen in all user groups. Giving patients an active role in managing a personal electronic health record is an innovative patient-centered approach, although existing restraints have to be recognized. To enhance user adoption and advance PEPAs potential, key user needs have to be addressed.

  2. Chemical bond activation observed with an x-ray laser

    International Nuclear Information System (INIS)

    Beye, Martin; Öberg, Henrik; Xin, Hongliang

    2016-01-01

    The concept of bonding and anti-bonding orbitals is fundamental in chemistry. The population of those orbitals and the energetic difference between the two reflect the strength of the bonding interaction. Weakening the bond is expected to reduce this energetic splitting, but the transient character of bond-activation has so far prohibited direct experimental access. Lastly, we apply time-resolved soft X-ray spectroscopy at a free-electron laser to directly observe the decreased bonding–anti-bonding splitting following bond-activation using an ultra short optical laser pulse.

  3. Electronic structure and photocatalytic activity of wurtzite Cu–Ga–S nanocrystals and their Zn substitution

    KAUST Repository

    Kandiel, Tarek

    2015-03-23

    Stoichiometric and gallium-rich wurtzite Cu-Ga-S ternary nanocrystals were synthesized via a facile solution-based hot injection method using 1-dodecanethiol as a sulfur source. The use of 1-dodecanethiol was found to be essential not only as a sulfur source but also as a structure-directing reagent to form a metastable wurtzite structure. In addition, the substitution of zinc in the wurtzite gallium-rich Cu-Ga-S nanocrystals was also investigated. The obtained nanocrystals were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), diffuse reflectance spectroscopy (DRS), photoluminescence (PL), and inductively coupled plasma atomic emission spectroscopy (ICP-OES). Electronic structures of pristine and the Zn-substituted Cu-Ga-S system were investigated using density functional theory (DFT) with HSE06 exchange-correlation functional. The calculated bandgaps accurately reflect the measured ones. The allowed electronic transitions occur upon the photon absorption from the (Cu + S) band towards the (Ga + S) one. The Zn substitution was found not to contribute to the band edge structure and hence altered the bandgaps only slightly, the direct transition nature remaining unchanged with the Zn substitution. The photocatalytic activities of H2 evolution from an aqueous Na2S/Na2SO3 solution under visible-light illumination on the synthesized nanocrystals were investigated. While the stoichiometric CuGaS2 exhibited negligible activity, the gallium-rich Cu-Ga-S ternary nanocrystals displayed reasonable activity. The optimum Zn substitution in the gallium-rich Cu-Ga-S ternary nanocrystals enhanced the H2 evolution rate, achieving an apparent quantum efficiency of >6% at 400 nm. © 2015 The Royal Society of Chemistry.

  4. Electronic word of mouth on twitter about physical activity in the United States: exploratory infodemiology study.

    Science.gov (United States)

    Zhang, Ni; Campo, Shelly; Janz, Kathleen F; Eckler, Petya; Yang, Jingzhen; Snetselaar, Linda G; Signorini, Alessio

    2013-11-20

    Twitter is a widely used social medium. However, its application in promoting health behaviors is understudied. In order to provide insights into designing health marketing interventions to promote physical activity on Twitter, this exploratory infodemiology study applied both social cognitive theory and the path model of online word of mouth to examine the distribution of different electronic word of mouth (eWOM) characteristics among personal tweets about physical activity in the United States. This study used 113 keywords to retrieve 1 million public tweets about physical activity in the United States posted between January 1 and March 31, 2011. A total of 30,000 tweets were randomly selected and sorted based on numbers generated by a random number generator. Two coders scanned the first 16,100 tweets and yielded 4672 (29.02%) tweets that they both agreed to be about physical activity and were from personal accounts. Finally, 1500 tweets were randomly selected from the 4672 tweets (32.11%) for further coding. After intercoder reliability scores reached satisfactory levels in the pilot coding (100 tweets separate from the final 1500 tweets), 2 coders coded 750 tweets each. Descriptive analyses, Mann-Whitney U tests, and Fisher exact tests were performed. Tweets about physical activity were dominated by neutral sentiments (1270/1500, 84.67%). Providing opinions or information regarding physical activity (1464/1500, 97.60%) and chatting about physical activity (1354/1500, 90.27%) were found to be popular on Twitter. Approximately 60% (905/1500, 60.33%) of the tweets demonstrated users' past or current participation in physical activity or intentions to participate in physical activity. However, social support about physical activity was provided in less than 10% of the tweets (135/1500, 9.00%). Users with fewer people following their tweets (followers) (P=.02) and with fewer accounts that they followed (followings) (P=.04) were more likely to talk positively about

  5. Cannabinoid-Induced Changes in the Activity of Electron Transport Chain Complexes of Brain Mitochondria.

    Science.gov (United States)

    Singh, Namrata; Hroudová, Jana; Fišar, Zdeněk

    2015-08-01

    The aim of this study was to investigate changes in the activity of individual mitochondrial respiratory chain complexes (I, II/III, IV) and citrate synthase induced by pharmacologically different cannabinoids. In vitro effects of selected cannabinoids on mitochondrial enzymes were measured in crude mitochondrial fraction isolated from pig brain. Both cannabinoid receptor agonists, Δ(9)-tetrahydrocannabinol, anandamide, and R-(+)-WIN55,212-2, and antagonist/inverse agonists of cannabinoid receptors, AM251, and cannabidiol were examined in pig brain mitochondria. Different effects of these cannabinoids on mitochondrial respiratory chain complexes and citrate synthase were found. Citrate synthase activity was decreased only by Δ(9)-tetrahydrocannabinol and AM251. Significant increase in the complex I activity was induced by anandamide. At micromolar concentration, all the tested cannabinoids inhibited the activity of electron transport chain complexes II/III and IV. Stimulatory effect of anandamide on activity of complex I may participate on distinct physiological effects of endocannabinoids compared to phytocannabinoids or synthetic cannabinoids. Common inhibitory effect of cannabinoids on activity of complex II/III and IV confirmed a non-receptor-mediated mechanism of cannabinoid action on individual components of system of oxidative phosphorylation.

  6. Impact of accelerated electrons on activating process and foaming potential of sludge

    International Nuclear Information System (INIS)

    Cuba, V.; Pospisil, M.; Mucka, V.; Silber, R.; Jenicek, P.; Dohanyos, M.; Zabranska, J.

    2002-01-01

    Complete text of publication follows. Presently, anaerobic and/or aerobic biological treatment is the cheapest and the most effective method of wastewater and sludge processing. However, due to some non-biodegradable substances present in wastewater and also due to limited capacity of wastewater treatment plants, it is necessary to find effective processes, that would be complementary to existing sludge treatment methods. Beside chemical and physical processes, radiation technology seems to offer improvement of effectivity of biological treatment. The paper describes possibilities of irradiation in activating process. Activated sludge can be affected in all its parameters, including physico chemical properties, such as sedimentation rate, or resulting volume of sludge. For the purpose of this research, laboratory experimental reactors simulating activating process were operated. According to previous results, accelerated electrons were used for irradiation, for e-beam seems to be more expedient than gamma irradiation. Reactor with irradiated sludge has been compared with the one without irradiation. It is shown, that pre-irradiation of sludge can positively affect following process of activation. Beside the activating process, another goal has been pursued. Radiation can strongly affect sludge foaming potential. Biological foaming caused by surfactant microorganisms, represents quite serious problem in many wastewater treatment plants, especially in digesters. It was proved that after irradiation foaming potential of sludge decreases. Pre-irradiation of activated sludge with relatively low doses also results in reduction of number of pathogenic microorganisms, presented in sludge

  7. Study of photo-activated electron transfer reactions in the first excited singlet state by picosecond and nanosecond laser spectroscopy

    International Nuclear Information System (INIS)

    Doizi, Denis

    1983-01-01

    Picosecond laser spectroscopy has been used to study two photo-activated electron transfer reactions: - a bimolecular electron transfer reaction between a sensitizer, DODCI, and an electron acceptor, methylviologen. The two radical ions created with an electron transfer efficiency γ ≅ 0.07 have been identified in picosecond and nanosecond laser absorption spectroscopy by adding selective solutes such as para-benzoquinone (an electron acceptor) or L(+) ascorbic acid (an electron donor). - an intramolecular electron transfer reaction in a triad molecule consisting of a tetra-aryl-porphyrin covalently linked to both a carotenoid and a quinone. The photoinduced charge separation occurs within 30 ps and leads, with a yield of 25 pc, to the formation of a zwitterion whose half-life is 2.5 μs. The experimental results obtained in these two studies show an effective decrease in the recombination rate of the two radical ions created in the encounter pair. (author) [fr

  8. Mapping travelling convection vortex events with respect to energetic particle boundaries

    DEFF Research Database (Denmark)

    Moretto, T.; Yahnin, A.

    1998-01-01

    Thirteen events of high-latitude ionospheric travelling convection vortices during very quiet conditions were identified in the Greenland magnetometer data during 1990 and 1991. The latitudes of the vortex centres for these events are compared to the energetic electron trapping boundaries...

  9. Activating "Invisible" Glue: Using Electron Beam for Enhancement of Interfacial Properties of Graphene-Metal Contact.

    Science.gov (United States)

    Kim, Songkil; Russell, Michael; Kulkarni, Dhaval D; Henry, Mathias; Kim, Steve; Naik, Rajesh R; Voevodin, Andrey A; Jang, Seung Soon; Tsukruk, Vladimir V; Fedorov, Andrei G

    2016-01-26

    Interfacial contact of two-dimensional graphene with three-dimensional metal electrodes is crucial to engineering high-performance graphene-based nanodevices with superior performance. Here, we report on the development of a rapid "nanowelding" method for enhancing properties of interface to graphene buried under metal electrodes using a focused electron beam induced deposition (FEBID). High energy electron irradiation activates two-dimensional graphene structure by generation of structural defects at the interface to metal contacts with subsequent strong bonding via FEBID of an atomically thin graphitic interlayer formed by low energy secondary electron-assisted dissociation of entrapped hydrocarbon contaminants. Comprehensive investigation is conducted to demonstrate formation of the FEBID graphitic interlayer and its impact on contact properties of graphene devices achieved via strong electromechanical coupling at graphene-metal interfaces. Reduction of the device electrical resistance by ∼50% at a Dirac point and by ∼30% at the gate voltage far from the Dirac point is obtained with concurrent improvement in thermomechanical reliability of the contact interface. Importantly, the process is rapid and has an excellent insertion potential into a conventional fabrication workflow of graphene-based nanodevices through single-step postprocessing modification of interfacial properties at the buried heterogeneous contact.

  10. Reverse electron flow-induced ROS production is attenuated by activation of mitochondrial Ca2+-sensitive K+ channels

    NARCIS (Netherlands)

    Heinen, André; Aldakkak, Mohammed; Stowe, David F.; Rhodes, Samhita S.; Riess, Matthias L.; Varadarajan, Srinivasan G.; Camara, Amadou K. S.

    2007-01-01

    Mitochondria generate reactive oxygen species (ROS) dependent on substrate conditions, O(2) concentration, redox state, and activity of the mitochondrial complexes. It is well known that the FADH(2)-linked substrate succinate induces reverse electron flow to complex I of the electron transport chain

  11. Zolpidem, a clinical hypnotic that affects electronic transfer, alters synaptic activity through potential GABA receptors in the nervous system without significant free radical generation.

    Science.gov (United States)

    Kovacic, Peter; Somanathan, Ratnasamy

    2009-01-01

    Zolpidem (trade name Ambien) has attracted much interest as a sleep-inducing agent and also in research. Attention has been centered mainly on receptor binding and electrochemistry in the central nervous system which are briefly addressed herein. A novel integrated approach to mode of action is presented. The pathways to be discussed involve basicity, reduction potential, electrostatics, cell signaling, GABA receptor binding, electron transfer (ET), pharmacodynamics, structure activity relationships (SAR) and side effects. The highly conjugated pyridinium salt formed by protonation of the amidine moiety is proposed to be the active form acting as an ET agent. Extrapolation of reduction potentials for related compounds supports the premise that zolpidem may act as an ET species in vivo. From recent literature reports, electrostatics is believed to play a significant role in drug action. The pyridinium cation displays molecular electrostatic potential which may well play a role energetically or as a bridging mechanism. An SAR analysis points to analogy with other physiologically active xenobiotics, namely benzodiazepines and paraquat in the conjugated iminium category. Inactivity of metabolites indicates that the parent is the active form of zolpidem. Absence of reactive oxygen species and oxidative stress is in line with minor side effects. In contrast, generally, the prior literature contains essentially no discussion of these fundamental biochemical relationships. Pharmacodynamics may play an important role. Concerning behavior at the blood-brain barrier, useful insight can be gained from investigations of the related cationic anesthetics that are structurally related to acetyl choline. Evidently, the neutral form of the drug penetrates the neuronal membrane, with the salt form operating at the receptor. The pathways of zolpidem have several clinical implications since the agent affects sedation, electroencephalographic activity, oxidative metabolites and

  12. Preliminary Breakdown: Physical Mechanisms and Potential for Energetic Emissions

    Science.gov (United States)

    Petersen, D.; Beasley, W. H.

    2014-12-01

    Observations and analysis of the preliminary breakdown phase of virgin negative cloud-to-ground (-CG) lightning strokes will be presented. Of primary interest are the physical processes responsible for the fast electric field "characteristic" pulses that are often observed during this phase. The pulse widths of characteristic pulses are shown to occur as a superposed bimodal distribution, with the short and long modes having characteristic timescales on the order of 1 microsecond and 10 microseconds, respectively. Analysis of these pulses is based on comparison with laboratory observations of long spark discharge processes and with recently acquired high-speed video observations of a single -CG event. It will be argued that the fast electric field bimodal distribution is the result of conventional discharge processes operating in an extensive strong ambient electric field environment. An important related topic will also be discussed, where it will be argued that preliminary breakdown discharges are capable of generating energetic electrons and may therefore seed relativistic electron avalanches that go on to produce pulsed energetic photon emissions.

  13. The Two Sources of Solar Energetic Particles

    Science.gov (United States)

    Reames, Donald V.

    2013-06-01

    Evidence for two different physical mechanisms for acceleration of solar energetic particles (SEPs) arose 50 years ago with radio observations of type III bursts, produced by outward streaming electrons, and type II bursts from coronal and interplanetary shock waves. Since that time we have found that the former are related to "impulsive" SEP events from impulsive flares or jets. Here, resonant stochastic acceleration, related to magnetic reconnection involving open field lines, produces not only electrons but 1000-fold enhancements of 3He/4He and of ( Z>50)/O. Alternatively, in "gradual" SEP events, shock waves, driven out from the Sun by coronal mass ejections (CMEs), more democratically sample ion abundances that are even used to measure the coronal abundances of the elements. Gradual events produce by far the highest SEP intensities near Earth. Sometimes residual impulsive suprathermal ions contribute to the seed population for shock acceleration, complicating the abundance picture, but this process has now been modeled theoretically. Initially, impulsive events define a point source on the Sun, selectively filling few magnetic flux tubes, while gradual events show extensive acceleration that can fill half of the inner heliosphere, beginning when the shock reaches ˜2 solar radii. Shock acceleration occurs as ions are scattered back and forth across the shock by resonant Alfvén waves amplified by the accelerated protons themselves as they stream away. These waves also can produce a streaming-limited maximum SEP intensity and plateau region upstream of the shock. Behind the shock lies the large expanse of the "reservoir", a spatially extensive trapped volume of uniform SEP intensities with invariant energy-spectral shapes where overall intensities decrease with time as the enclosing "magnetic bottle" expands adiabatically. These reservoirs now explain the slow intensity decrease that defines gradual events and was once erroneously attributed solely to slow

  14. Gas-Phase Energetics of Actinide Oxides: An Assessment of Neutral and Cationic Monoxides and Dioxides from Thorium to Curium

    Science.gov (United States)

    Marçalo, Joaquim; Gibson, John K.

    2009-09-01

    An assessment of the gas-phase energetics of neutral and singly and doubly charged cationic actinide monoxides and dioxides of thorium, protactinium, uranium, neptunium, plutonium, americium, and curium is presented. A consistent set of metal-oxygen bond dissociation enthalpies, ionization energies, and enthalpies of formation, including new or revised values, is proposed, mainly based on recent experimental data and on correlations with the electronic energetics of the atoms or cations and with condensed-phase thermochemistry.

  15. The energetics of AGN radiation pressure-driven outflows

    Science.gov (United States)

    Ishibashi, W.; Fabian, A. C.; Maiolino, R.

    2018-05-01

    The increasing observational evidence of galactic outflows is considered as a sign of active galactic nucleus (AGN) feedback in action. However, the physical mechanism responsible for driving the observed outflows remains unclear, and whether it is due to momentum, energy, or radiation is still a matter of debate. The observed outflow energetics, in particular the large measured values of the momentum ratio (\\dot{p}/(L/c) ˜ 10) and energy ratio (\\dot{E}_k/L ˜ 0.05), seems to favour the energy-driving mechanism; and most observational works have focused their comparison with wind energy-driven models. Here, we show that AGN radiation pressure on dust can adequately reproduce the observed outflow energetics (mass outflow rate, momentum flux, and kinetic power), as well as the scalings with luminosity, provided that the effects of radiation trapping are properly taken into account. In particular, we predict a sublinear scaling for the mass outflow rate (\\dot{M} ∝ L^{1/2}) and a superlinear scaling for the kinetic power (\\dot{E}_k ∝ L^{3/2}), in agreement with the observational scaling relations reported in the most recent compilation of AGN outflow data. We conclude that AGN radiative feedback can account for the global outflow energetics, at least equally well as the wind energy-driving mechanism, and therefore both physical models should be considered in the interpretation of future AGN outflow observations.

  16. Electron microscope investigations of activated chalcopyrite particles via the FLSmidth® ROL process

    DEFF Research Database (Denmark)

    Karcz, Adam Paul; Damø, Anne Juul; Illerup, Jytte Boll

    2017-01-01

    Because of its unique semiconductor properties, the world’s most abundant copper mineral, chalcopyrite (CuFeS2), is refractory with respect to atmospheric leaching using traditional acidic ferric sulfate lixiviants. FLSmidth® has developed a novel approach manipulating lattice properties of semi.......1 and 5 mol percent of copper (II) to dope the lattice and thereby “activate” chalcopyrite. Since lattice restructuring can have such a dramatic influence on semiconductor reactivity, the associated physico-chemical phenomena are worth studying. In this regard, we investigate the relationship between...... chemical activation and deformation of the chalcopyrite crystal lattice through the use of electron microscopy. Although the activation process took only an hour and the extent of conversion was on the order of a few mol%, the lattice was found to be strained throughout the particle. This paper draws some...

  17. Smartphone data as an electronic biomarker of illness activity in bipolar disorder

    DEFF Research Database (Denmark)

    Faurholt-Jepsen, Maria; Vinberg, Maj; Frost, Mads

    2015-01-01

    Objectives Objective methods are lacking for continuous monitoring of illness activity in bipolar disorder. Smartphones offer unique opportunities for continuous monitoring and automatic collection of real-time data. The objectives of the paper were to test the hypotheses that (i) daily electronic...... self-monitored data and (ii) automatically generated objective data collected using smartphones correlate with clinical ratings of depressive and manic symptoms in patients with bipolar disorder. Methods Software for smartphones (the MONARCA I system) that collects automatically generated objective......-monitored data (i.e., mood and activity) and scores on the YMRS. Finally, the automatically generated objective data were able to discriminate between affective states. Conclusions Automatically generated objective data and self-monitored data collected using smartphones correlate with clinically rated...

  18. QUANTITATIVE ELECTRONIC STRUCTURE - ACTIVITY RELATIONSHIP OF ANTIMALARIAL COMPOUND OF ARTEMISININ DERIVATIVES USING PRINCIPAL COMPONENT REGRESSION APPROACH

    Directory of Open Access Journals (Sweden)

    Paul Robert Martin Werfette

    2010-06-01

    Full Text Available Analysis of quantitative structure - activity relationship (QSAR for a series of antimalarial compound artemisinin derivatives has been done using principal component regression. The descriptors for QSAR study were representation of electronic structure i.e. atomic net charges of the artemisinin skeleton calculated by AM1 semi-empirical method. The antimalarial activity of the compound was expressed in log 1/IC50 which is an experimental data. The main purpose of the principal component analysis approach is to transform a large data set of atomic net charges to simplify into a data set which known as latent variables. The best QSAR equation to analyze of log 1/IC50 can be obtained from the regression method as a linear function of several latent variables i.e. x1, x2, x3, x4 and x5. The best QSAR model is expressed in the following equation,  (;;   Keywords: QSAR, antimalarial, artemisinin, principal component regression

  19. Integrating nanotubes into microsystems with electron beam lithography and in situ catalytically activated growth

    DEFF Research Database (Denmark)

    Gjerde, Kjetil; Fornés-Mora, Marc; Kjelstrup-Hansen, Jakob

    2006-01-01

    Integration of freestanding wire-like structures such as multi walled carbon nanotubes (MWCNT) into microsystems has many potential applications. Devices such as AFM tips or improved electrodes for conductivity measurements are obvious candidates. Catalytically activated growth opens up the possi......Integration of freestanding wire-like structures such as multi walled carbon nanotubes (MWCNT) into microsystems has many potential applications. Devices such as AFM tips or improved electrodes for conductivity measurements are obvious candidates. Catalytically activated growth opens up...... the possibility of waferscale fabrication of such devices. We combine conventional microfabrication techniques with state of the art electron beam lithography (EBL) to precisely position catalyst nanoparticles with sub 100 nm diameter into the microsystems. In particular, we have explored two main approaches...

  20. Treatment of industrial effluents using electron beam accelerator and adsorption with activated carbon. A comparative study

    International Nuclear Information System (INIS)

    Las Casas, Alexandre

    2004-01-01

    Several methods are used In the pollutant removal from Industrial and domestic wastewater. However when the degradation of toxic organic pollutants, mainly the recalcitrant is objectified, the conventional treatments usually do not meet the desirable performance in the elimination or decrease the impact when the effluent are released to the environment what takes to the research of alternative methods that seek the improvement of the efficiency of the wastewater treatment systems jointly employees or separately. This work presents a study of degradation/removal of pollutants organic compounds comparing two methods using radiation from industrial electron beam and granular activated carbon (GAC). The removal efficiency of the pollutants was evaluated and it was verified that the efficiency of adsorption with activated carbon is similar to the radiation method. The obtained results allowed to evaluated the relative costs of these methods. (author)

  1. Association between electronic equipment in the bedroom and sedentary lifestyle, physical activity, and body mass index of children

    Directory of Open Access Journals (Sweden)

    Gerson Luis de Moraes Ferrari

    2015-11-01

    Conclusion: Electronic equipment in the children's bedroom can negatively affect moderate‐to‐vigorous physical activity and body mass index regardless of gender, school, and annual family income, which can contribute to physical inactivity and childhood obesity.

  2. Energetic Particles at High Latitudes of the Heliosphere

    International Nuclear Information System (INIS)

    Zhang Ming

    2004-01-01

    Ulysses has by now made two complete out-of-ecliptic orbits around the sun. The first encounter of the solar poles occurred in 1994-1995, when the sun was near the minimum of its activity cycle, while the second one was in 2000-2001, when the sun was at solar maximum. To our surprise, energetic particles of all origins at high latitude are not much different from those we observe near the ecliptic for at least these two phases of solar cycle. The latitude gradients of galactic and anomalous cosmic rays are positive but small at the 1994-1995 solar minimum and almost zero at the 2000-2001 solar maximum, while temporal solar cycle variation dominates their flux variation at all latitudes. Solar energetic particles from all large gradual events can be seen at both Ulysses and Earth no matter how large their spatial separations from the solar event are, and the particle flux often reaches a uniform level in the entire inner heliosphere within a few days after event onset and remains so throughout the decay phase that can sometimes last over a month. Energetic particles accelerated by low-latitude CIRs can appear at high latitudes, far beyond the latitudinal range of CIRs. All these observations suggest that latitudinal transport of energetic particles is quite easy. In addition, because the average magnetic field is radial at the pole, The Ulysses observations indicate that parallel diffusion and drift in the radial direction need to be reduced at the poles relative to their equatorial values. To achieve such behaviors of particle transport, the heliospheric magnetic field needs a significant latitudinal component at the poles. A non-zero latitudinal magnetic field component can be produced by latitudinal motion of the magnetic field line in solar corona, which can be in form of either random walk suggested by Jokipii or large scale systematic motion suggested by Fisk

  3. Solar energetic particles: observational studies and magnetohydrodynamic simulation

    International Nuclear Information System (INIS)

    Masson, S.

    2010-10-01

    Solar activity manifests itself through highly dynamical events, such as flares and coronal mass ejections, which result in energy release by magnetic reconnection. This thesis focuses on two manifestations of this energy release: solar energetic particles and dynamics of magnetic reconnection. The first part of my work consists in the detailed temporal analysis of several electromagnetic signatures, produced by energetic particles in the solar atmosphere, with respect to the energetic particle flux at Earth. Using multi-instrument observations, I highlighted that particles can be accelerated by the flare to relativistic energies during a specific episode of acceleration in the impulsive phase. This showed that particles traveled a longer path length than the theoretical length generally assumed. Using in-situ measurements of magnetic field and plasma, I identified the interplanetary magnetic field for 10 particle events, and performing a velocity dispersion analysis I obtained the interplanetary length traveled by particles. I showed that the magnetic structure of the interplanetary medium play a crucial role in the association of the particle flux at Earth and the acceleration signatures of particles at the Sun. The second part of my work focuses on the dynamics of magnetic reconnection. Observationally, the best evidence for magnetic reconnection is the appearance of brightnesses at the solar surface. Performing the first data-driven 3 dimensional magneto-hydrodynamic (MHD) simulation of an observed event, I discovered that the evolution of brightnesses can be explained by the succession of two different reconnection regimes, induced by a new topological association where null-point separatrix lines are embedded in quasi-separatrix layers. This new topological association induces a change of field line connectivity, but also a continuous reconnection process, leading to an apparent slipping motion of reconnected field lines. From a MHD simulation I showed that

  4. Detection of actinides with an electron accelerator by active photoneutron interrogation measurements

    International Nuclear Information System (INIS)

    Sari, A.; Carrel, F.; Gmar, M.; Laine, F.; Normand, S.; Lyoussi, A.

    2012-01-01

    The solution for management of a nuclear waste package is chosen according to its radiological characteristics. One of the most important of these features is the α-activity which is due to actinides ( 235 U, 238 U, 239 Pu, etc.) If non-destructive passive methods are not sufficient to quantify the latter, non-destructive active methods based on the fission process represent a solution of interest. First, these methods consist in irradiating a package in order to induce fission reactions on the actinides, and then, to detect the prompt and delayed particles which are emitted following these reactions. Our aim is to conduct neutron interrogation measurements on nuclear waste packages using an electron accelerator as a photoneutron generator. One of the main interests of this approach is that the intensity of the neutron flux can be one or two orders of magnitude higher than the one delivered by a deuterium-tritium generator. With the objective of improving nuclear waste characterization, the development of this method could enable the integration of three complementary techniques on a single measurement cell (active neutron interrogation, active photon interrogation, and high-energy imaging). In this paper, simulation and experimental results are presented. A simulation study using MCNPX has been conducted in order to determine the characteristics of the photoneutron flux emitted by the electron accelerator of the SAPHIR facility owned by CEA LIST. Energy spectra, angular distribution and intensity of the photoneutron flux have been obtained. A photoneutron interrogation measurement cell based on this accelerator has been built and assessed by carrying out measurements on uranium samples. Delayed gamma-ray spectra have been acquired and enabled to confirm the experimental feasibility of our method. (authors)

  5. Electronic bypass of spinal lesions: activation of lower motor neurons directly driven by cortical neural signals.

    Science.gov (United States)

    Li, Yan; Alam, Monzurul; Guo, Shanshan; Ting, K H; He, Jufang

    2014-07-03

    Lower motor neurons in the spinal cord lose supraspinal inputs after complete spinal cord injury, leading to a loss of volitional control below the injury site. Extensive locomotor training with spinal cord stimulation can restore locomotion function after spinal cord injury in humans and animals. However, this locomotion is non-voluntary, meaning that subjects cannot control stimulation via their natural "intent". A recent study demonstrated an advanced system that triggers a stimulator using forelimb stepping electromyographic patterns to restore quadrupedal walking in rats with spinal cord transection. However, this indirect source of "intent" may mean that other non-stepping forelimb activities may false-trigger the spinal stimulator and thus produce unwanted hindlimb movements. We hypothesized that there are distinguishable neural activities in the primary motor cortex during treadmill walking, even after low-thoracic spinal transection in adult guinea pigs. We developed an electronic spinal bridge, called "Motolink", which detects these neural patterns and triggers a "spinal" stimulator for hindlimb movement. This hardware can be head-mounted or carried in a backpack. Neural data were processed in real-time and transmitted to a computer for analysis by an embedded processor. Off-line neural spike analysis was conducted to calculate and preset the spike threshold for "Motolink" hardware. We identified correlated activities of primary motor cortex neurons during treadmill walking of guinea pigs with spinal cord transection. These neural activities were used to predict the kinematic states of the animals. The appropriate selection of spike threshold value enabled the "Motolink" system to detect the neural "intent" of walking, which triggered electrical stimulation of the spinal cord and induced stepping-like hindlimb movements. We present a direct cortical "intent"-driven electronic spinal bridge to restore hindlimb locomotion after complete spinal cord injury.

  6. The potential for the exploration of activity patterns in the urban landscape with GPS-positioning and electronic activity diaries

    DEFF Research Database (Denmark)

    Hovgesen, Henrik Harder; Nielsen, Thomas Alexander Sick; Lassen, Claus

    2005-01-01

    rythms affects the different parts of the city. GPS-based tracking has previously mainly been used to track vehicle movements, fx. in transportation surveys. The use of personal devices makes it foremost possible to place the individual respondents use of urban space in its context of transport routes......, other locations visited and the individuals total time budget. In the cross-disciplinary research project Space – Time – Flows currently being started at Aalborg University, the GPS/electronic diary technology is intended as a means to disclosure the imprint of information and communication technologies...... on the use of urban space. The core of the work will be an equal treatment of activities in the virtual as well as the physical world. Substitution effects between the virtual and the physical world will be in focus, together with differences between the spatio-temporal patterns of groups with different...

  7. Tuning the Electronic Structure of Titanium Oxide Support to Enhance the Electrochemical Activity of Platinum Nanoparticles

    KAUST Repository

    Shi, Feifei

    2013-09-11

    Two times higher activity and three times higher stability in methanol oxidation reaction, a 0.12 V negative shift of the CO oxidation peak potential, and a 0.07 V positive shift of the oxygen reaction potential compared to Pt nanoparticles on pristine TiO2 support were achieved by tuning the electronic structure of the titanium oxide support of Pt nanoparticle catalysts. This was accomplished by adding oxygen vacancies or doping with fluorine. Experimental trends are interpreted in the context of an electronic structure model, showing an improvement in electrochemical activity when the Fermi level of the support material in Pt/TiOx systems is close to the Pt Fermi level and the redox potential of the reaction. The present approach provides guidance for the selection of the support material of Pt/TiOx systems and may be applied to other metal-oxide support materials, thus having direct implications in the design and optimization of fuel cell catalyst supports. © 2013 American Chemical Society.

  8. Electronics department progress report. Basic and applied research activity 1975-1977

    International Nuclear Information System (INIS)

    1978-10-01

    The electronics department at Risoe National Laboratory, Denmark, comprises about 80 people and is made up of essentially two main divisions. One deals with the provision of instrumentation and measurement expertise for the different groups at Risoe who conduct basic research or technological R and D. This division employs a group of scientific electronics consultants, a production group, a maintenance facility and a central instrument pool for the complete site. The other division, whose work is reported here, is engaged in both basic and applied research in topics and areas of direct interest to the department itself. These involve the development and evaluation of methods, for example, in the field of plant reliability and safety as well as in a group engaged in nuclear geophysical activities - including mineral prospecting in Greenland. Another team is working with man-machine problems in highly automated systems and the associated needs for computer support in connection with proper job allocation and design. Finally, a group is active in the field of applied laser physics. The time period covered is 1975-1977. (author/BP)

  9. Effect of Electronic Messaging on Physical Activity Participation among Older Adults

    Directory of Open Access Journals (Sweden)

    Chantrell Antoine Parker

    2016-01-01

    Full Text Available The purpose of this study was to determine if electronic messaging would increase min of aerobic physical activity (PA among older adults. Participants were active older adults (n=28; M age = 60 years, SD = 5.99, and range = 51–74 years. Using an incomplete within-subjects crossover design, participants were randomly assigned to begin the 4-week study receiving the treatment condition (a morning and evening text message or the control condition (an evening text message. Participants self-reported min of completed aerobic PA by cell phone text. The 1-way within-subjects ANOVA showed significant group differences (p<0.05. Specifically, when participants were in the treatment condition, they reported significantly greater average weekly min of aerobic PA (M = 96.88 min, SD = 62.9 compared to when they completed the control condition (M = 71.68 min, SD = 40.98. Electronic messaging delivered via cell phones was effective at increasing min of aerobic PA among older adults.

  10. One size fits all electronics for insole-based activity monitoring.

    Science.gov (United States)

    Hegde, Nagaraj; Bries, Matthew; Melanson, Edward; Sazonov, Edward

    2017-07-01

    Footwear based wearable sensors are becoming prominent in many areas of monitoring health and wellness, such as gait and activity monitoring. In our previous research we introduced an insole based wearable system SmartStep, which is completely integrated in a socially acceptable package. From a manufacturing perspective, SmartStep's electronics had to be custom made for each shoe size, greatly complicating the manufacturing process. In this work we explore the possibility of making a universal electronics platform for SmartStep - SmartStep 3.0, which can be used in the most common insole sizes without modifications. A pilot human subject experiments were run to compare the accuracy between the one-size fits all (SmartStep 3.0) and custom size SmartStep 2.0. A total of ~10 hours of data was collected in the pilot study involving three participants performing different activities of daily living while wearing SmartStep 2.0 and SmartStep 3.0. Leave one out cross validation resulted in a 98.5% average accuracy from SmartStep 2.0, while SmartStep 3.0 resulted in 98.3% accuracy, suggesting that the SmartStep 3.0 can be as accurate as SmartStep 2.0, while fitting most common shoe sizes.

  11. Balancing the Hydrogen Evolution Reaction, Surface Energetics, and Stability of Metallic MoS2 Nanosheets via Covalent Functionalization.

    Science.gov (United States)

    Benson, Eric E; Zhang, Hanyu; Schuman, Samuel A; Nanayakkara, Sanjini U; Bronstein, Noah D; Ferrere, Suzanne; Blackburn, Jeffrey L; Miller, Elisa M

    2018-01-10

    We modify the fundamental electronic properties of metallic (1T phase) nanosheets of molybdenum disulfide (MoS 2 ) through covalent chemical functionalization, and thereby directly influence the kinetics of the hydrogen evolution reaction (HER), surface energetics, and stability. Chemically exfoliated, metallic MoS 2 nanosheets are functionalized with organic phenyl rings containing electron donating or withdrawing groups. We find that MoS 2 functionalized with the most electron donating functional group (p-(CH 3 CH 2 ) 2 NPh-MoS 2 ) is the most efficient catalyst for HER in this series, with initial activity that is slightly worse compared to the pristine metallic phase of MoS 2 . The p-(CH 3 CH 2 ) 2 NPh-MoS 2 is more stable than unfunctionalized metallic MoS 2 and outperforms unfunctionalized metallic MoS 2 for continuous H 2 evolution within 10 min under the same conditions. With regards to the entire studied series, the overpotential and Tafel slope for catalytic HER are both directly correlated with the electron donating strength of the functional group. The results are consistent with a mechanism involving ground-state electron donation or withdrawal to/from the MoS 2 nanosheets, which modifies the electron transfer kinetics and catalytic activity of the MoS 2 nanosheet. The functional groups preserve the metallic nature of the MoS 2 nanosheets, inhibiting conversion to the thermodynamically stable semiconducting state (2H) when mildly annealed in a nitrogen atmosphere. We propose that the electron density and, therefore, reactivity of the MoS 2 nanosheets are controlled by the attached functional groups. Functionalizing nanosheets of MoS 2 and other transition metal dichalcogenides provides a synthetic chemical route for controlling the electronic properties and stability within the traditionally thermally unstable metallic state.

  12. Charge equilibrium processes of energetic incident ions and their range

    International Nuclear Information System (INIS)

    Kawagoshi, Hiroshi; Karashima, Shosuke; Watanabe, Tsutomu.

    1984-01-01

    The charge state of energetic ions passing through a certain matter is varied by charge-exchange processes. A rate equation for charge fraction is given by using electron loss and capture cross sections in collision with a target atom under idealized condition. We solved the rate equation of the charge-exchange process of a single electron in a form of linear coupled differential equation. Our calcuiation for the range of ion were carried out for He, Ne and Ar ions passing through an atomic hydrogen gas target. We discuss the charge states of the projectile in relation to a local charge balance consituting a state of charge equilibrium in the target. (author)

  13. Structure and energetics of nanotwins in cubic boron nitrides

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Shijian, E-mail: sjzheng@imr.ac.cn, E-mail: zrf@buaa.edu.cn; Ma, Xiuliang [Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Zhang, Ruifeng, E-mail: sjzheng@imr.ac.cn, E-mail: zrf@buaa.edu.cn [School of Materials Science and Engineering, and International Research Institute for Multidisciplinary Science, Beihang University, Beijing 100191 (China); Huang, Rong [Key Laboratory of Polar Materials and Devices, Ministry of Education, East China Normal University, Shanghai 200062 (China); Taniguchi, Takashi [National Institute for Materials Science, Tsukuba, Ibaraki 305-0044 (Japan); Ikuhara, Yuichi [Nanostructures Research Laboratory, Japan Fine Ceramics Center, Nagoya 456-8587 (Japan); Institute of Engineering Innovation, The University of Tokyo, Tokyo 113-8656 (Japan); Beyerlein, Irene J. [Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

    2016-08-22

    Recently, nanotwinned cubic boron nitrides (NT c-BN) have demonstrated extraordinary leaps in hardness. However, an understanding of the underlying mechanisms that enable nanotwins to give orders of magnitude increases in material hardness is still lacking. Here, using transmission electron microscopy, we report that the defect density of twin boundaries depends on nanotwin thickness, becoming defect-free, and hence more stable, as it decreases below 5 nm. Using ab initio density functional theory calculations, we reveal that the Shockley partials, which may dominate plastic deformation in c-BNs, show a high energetic barrier. We also report that the c-BN twin boundary has an asymmetrically charged electronic structure that would resist migration of the twin boundary under stress. These results provide important insight into possible nanotwin hardening mechanisms in c-BN, as well as how to design these nanostructured materials to reach their full potential in hardness and strength.

  14. Van Allen Probes Measurements of Energetic Particle Deep Penetration Into the Low L Region (L Storm on 8 April 2016

    Science.gov (United States)

    Zhao, H.; Baker, D. N.; Califf, S.; Li, X.; Jaynes, A. N.; Leonard, T.; Kanekal, S. G.; Blake, J. B.; Fennell, J. F.; Claudepierre, S. G.; Turner, D. L.; Reeves, G. D.; Spence, H. E.

    2017-12-01

    Using measurements from the Van Allen Probes, a penetration event of tens to hundreds of keV electrons and tens of keV protons into the low L shells (L electric field represented by the Volland-Stern model or a uniform dawn-dusk electric field model based on the electric field measurements. It suggests that the underlying physical mechanism responsible for energetic electron deep penetration, which is very important for fully understanding energetic electron dynamics in the low L shells, should be MLT localized.

  15. Structural, energetic and electronic properties of intercalated boron

    Indian Academy of Sciences (India)

    Author Affiliations. S Rada1 M Rada2 E Culea1. Department of Physics & Chemistry, Technical University of Cluj-Napoca, Cluj-Napoca 400 020, Romania; National Institute for R&D of Isotopic and Molecular Technologies, Cluj-Napoca 400 293, Romania ...

  16. Electron energetics in the expanding solar wind via Helios observations

    Czech Academy of Sciences Publication Activity Database

    Štverák, Štěpán; Trávníček, Pavel M.; Hellinger, Petr

    2015-01-01

    Roč. 120, č. 10 (2015), s. 8177-8193 ISSN 2169-9380 Institutional support: RVO:68378289 Keywords : solar wind plasma * plasma energization * transport processes Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 3.318, year: 2015 http://onlinelibrary.wiley.com/doi/10.1002/2015JA021368/abstract

  17. Seventh meeting of the ITER physics expert group on energetic particles, heating and steady state operations

    International Nuclear Information System (INIS)

    Gormezano, C.

    1999-01-01

    The seventh meeting of the ITER Physics Group on energetic particles, heating and steady state operation was held at CEN/Cadarache from 14 to 18 September 1999. This was the first meeting following the redefinition of the Expert Group structure and it was also the first meeting without participation of US physicists. The main topics covered were: 1. Energetic Particles, 2. Ion Cyclotron Resonance Heating, 3. Lower Hybrid Current Drive, 4. Electron Cyclotron Resonance Heating and Current Drive, 5. Neutral Beam Injection, 6. Steady-State Aspects

  18. EUV-driven ionospheres and electron transport on extrasolar giant planets orbiting active stars

    Science.gov (United States)

    Chadney, J. M.; Galand, M.; Koskinen, T. T.; Miller, S.; Sanz-Forcada, J.; Unruh, Y. C.; Yelle, R. V.

    2016-03-01

    The composition and structure of the upper atmospheres of extrasolar giant planets (EGPs) are affected by the high-energy spectrum of their host stars from soft X-rays to the extreme ultraviolet (EUV). This emission depends on the activity level of the star, which is primarily determined by its age. In this study, we focus upon EGPs orbiting K- and M-dwarf stars of different ages - ɛ Eridani, AD Leonis, AU Microscopii - and the Sun. X-ray and EUV (XUV) spectra for these stars are constructed using a coronal model. These spectra are used to drive both a thermospheric model and an ionospheric model, providing densities of neutral and ion species. Ionisation - as a result of stellar radiation deposition - is included through photo-ionisation and electron-impact processes. The former is calculated by solving the Lambert-Beer law, while the latter is calculated from a supra-thermal electron transport model. We find that EGP ionospheres at all orbital distances considered (0.1-1 AU) and around all stars selected are dominated by the long-lived H+ ion. In addition, planets with upper atmospheres where H2 is not substantially dissociated (at large orbital distances) have a layer in which H3+ is the major ion at the base of the ionosphere. For fast-rotating planets, densities of short-lived H3+ undergo significant diurnal variations, with the maximum value being driven by the stellar X-ray flux. In contrast, densities of longer-lived H+ show very little day/night variability and the magnitude is driven by the level of stellar EUV flux. The H3+ peak in EGPs with upper atmospheres where H2 is dissociated (orbiting close to their star) under strong stellar illumination is pushed to altitudes below the homopause, where this ion is likely to be destroyed through reactions with heavy species (e.g. hydrocarbons, water). The inclusion of secondary ionisation processes produces significantly enhanced ion and electron densities at altitudes below the main EUV ionisation peak, as

  19. Adsorption and photocatalytic activity of electron-irradiated polystyrene nanosphere multi-layer film

    International Nuclear Information System (INIS)

    Cho, Sung Oh; Yoo, Seung Hwa; Kim, Jea Joon; Kum, Jong Min

    2012-01-01

    production from water, after the first report of poly(p-phenylene) (PPP) in 1990. Both of these work shows enhanced activity by incorporating a co-catalyst. However, to date, there is no reported literature about single material organic photocatalyst for removal of organic pollutant from water. In this paper, we present a novel low-cost, metal-free organic photocatalyst that consists of only carbon and hydrogen fabricated by electron-beam irradiation on polymer nanospheres. Characterization results and adsorption-photocatalytic activities are shown of electron-irradiated polystyrene (PS) nanospheres

  20. Energetic particle pressure in intense ESP events

    Science.gov (United States)

    Lario, D.; Decker, R. B.; Roelof, E. C.; Viñas, A.-F.

    2015-09-01

    We study three intense energetic storm particle (ESP) events in which the energetic particle pressure PEP exceeded both the pressure of the background thermal plasma Pth and the pressure of the magnetic field PB. The region upstream of the interplanetary shocks associated with these events was characterized by a depression of the magnetic field strength coincident with the increase of the energetic particle intensities and, when plasma measurements were available, a depleted solar wind density. The general feature of cosmic-ray mediated shocks such as the deceleration of the upstream background medium into which the shock propagates is generally observed. However, for those shocks where plasma parameters are available, pressure balance is not maintained either upstream of or across the shock, which may result from the fact that PEP is not included in the calculation of the shock parameters.